Bibliografias temáticas / Extraction des sources

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Literatura científica selecionada sobre o tema "Extraction des sources"

Autor: Grafiati

Publicado: 21 de dezembro de 2024

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Artigos de revistas sobre o assunto "Extraction des sources"

Rosales-Garcia, Teresa, Cristian Jimenez-Martinez e Gloria Davila-Ortiz. "Squalene Extraction: Biological Sources and Extraction Methods". International Journal of Environment, Agriculture and Biotechnology 2, n.º 4 (2017): 1662–70. http://dx.doi.org/10.22161/ijeab/2.4.26.

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Tan, Yew Ai, e Ainte Kuntom. "Hydrocarbons m Crude Palm Kernel Oil". Journal of AOAC INTERNATIONAL 77, n.º 1 (1 de janeiro de 1994): 67–73. http://dx.doi.org/10.1093/jaoac/77.1.67.

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Abstract The sources of hydrocarbons in crude palm kernel oil were investigated by a series of laboratory-controlled oil extractions of kernels of varying quality. Site examinations of palm kernel-crushing plants were also conducted to determine possible sources of hydrocarbon contamination of palm kernels throughout the process of kernel extraction. Parallel to these studies, a random survey of crude palm kernel oil (CPKO) produced by different kernel crushers was also carried out to determine the range of hydrocarbon concentrations in locally produced CPKO. This study showed that hydrocarbons can be picked up from sources such as glassware, extracting apparatus, and plastic containers and stoppers. Extraction of oil from low-quality kernels that were both moldy and rancid, broken kernels, and kernels plus added shells also resulted in a higher hydrocarbon level in the final CPKO. Overheating and cooking of the kernels before extraction also contributed to the overall hydrocarbon content. The random survey of hydrocarbon level showed a range of 0.6–7.1 ppm.

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Jovanovic, Aleksandra, Predrag Petrovic, Verica Ðordjevic, Gordana Zdunic, Katarina Savikin e Branko Bugarski. "Polyphenols extraction from plant sources". Lekovite sirovine, n.º 37 (2017): 45–49. http://dx.doi.org/10.5937/leksir1737045j.

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Kuber, B. Ramya, D. Sravya e I. Theja. "INNOVATIVE EMERGING TECHNOLOGIES FOR EXTRACTION OF PHYTOCHEMICALS FROM NATURAL SOURCES". International Journal on Biological Sciences 13, n.º 02 (2022): 120–26. http://dx.doi.org/10.53390/ijbs.v13i2.4.

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Due to their established health benefits, phytochemicals such as phenolics, carotenoids, sterols, and alkaloids are becoming more and more popular. However, some of these phytochemicals may not be amenable to typical extraction techniques. Examples of innovative methods include supercritical fluid extraction (SFE), microwave extraction (MWE), pulsed electric field (PEF), highpressure processing (HPP), and ultrasonic extraction (UE), and ohmic heating (OH). Supercritical fluid extraction is one of the methods that is most often researched and has already found commercial use for number of products. The most used supercritical fluid for agricultural products is carbon dioxide. Additionally growing, and already having commercial uses, is microwave extraction. By using electromagnetic radiation to quickly and uniformly heat the matrix, this technique produces extractions with high quantities of phytochemicals and few impurities. Despite current interest in pulsed electric fields, which have several benefits over thermal treatments, their usage is still limited to a small number of industrial units. Ohmic heating occurs when alternating current is sent through the matrix, heat is produced bysample's electrical resistance discharging. Low-frequency electrical energy is demonstrated to promote the extraction of phytochemicals since it dissipates into heat quickly and uniformly. High-pressure processing has potential to improve diffusion, increase mass transfer and cell permeability, and maintain food quality. HPP reduces negative effects of heat while greatly enhancing texture. HPP employs high pressures and moderate temperatures in comparison to traditional extraction techniques. With the employment of a combination of cutting-edge technologies that will enable the production of high-quality phytochemicals with little degradation, future of phytochemical extraction is undoubtedly brigh

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DA, Bansode. "Exploring Diverse Techniques for Phytochemical Extraction from Plant Sources A Comprehensive Review". International Journal of Pharmacognosy & Chinese Medicine 8, n.º 1 (28 de fevereiro de 2024): 1–11. http://dx.doi.org/10.23880/ipcm-16000266.

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The extraction of bioactive compounds from plant materials is imperative within the pharmaceutical industry. The standardization of extraction procedures is directed at the elimination of undesirable constituents, facilitating the isolation of the most enriched bioactive fraction from herbs. This refined fraction, obtained through the application of diverse solvent systems, is designed to optimize therapeutic potential. Phytochemicals derived from various plant components function as direct sources of medicinal agents, providing a comprehensive characterization of the myriad secondary metabolic compounds inherent in plants. The extraction of bioactive compounds, coupled with their quantitative and qualitative evaluation, assumes significance in the identification of novel biomolecules applicable to the pharmaceutical and agrochemical sectors. This review predominantly concentrates on analytical methodologies, incorporating extraction methods and the analysis of bioactive compounds in plant extracts through diverse techniques. Prominent progress in modern green extraction methods, such as supercritical fluid, ultrasound, accelerated solvent, microwave, and enzyme-assisted extraction, is gaining recognition. The critical assessment of extraction conditions in this review elucidates both conventional solvent-based and robust modern and green extraction techniques. Numerous methods have been devised to extract phytochemicals with efficiency, ensuring high quality, purity, and cost-effectiveness while minimizing environmental impact. Molecular hydrogen (H2) has emerged as a promising catalyst for enhancing phytochemical extraction from plant materials, presenting an innovative avenue for improving extraction efficiency

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Xiong, Yuecheng, Jingwen Zhou, Pengyi Lu, Jinwen Yin, Yunhao Wang e Zhanxi Fan. "Electrochemical lithium extraction from aqueous sources". Matter 5, n.º 6 (junho de 2022): 1760–91. http://dx.doi.org/10.1016/j.matt.2022.04.034.

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Tedmori, Sara, Thomas W. Jackson e Dino Bouchlaghem. "Locating knowledge sources through keyphrase extraction". Knowledge and Process Management 13, n.º 2 (2006): 100–107. http://dx.doi.org/10.1002/kpm.250.

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Sultana, Hujaifa, Abhinab Chetia, Abhigyan Saikia e Nekibul Jaman Khan. "An Updated Review on Extraction, Isolation, and Identification of Bioactive Compounds from Plant Extracts". Scholars Academic Journal of Pharmacy 12, n.º 07 (3 de julho de 2023): 154–71. http://dx.doi.org/10.36347/sajp.2023.v12i07.001.

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Plant extracts have long been used for their medicinal qualities and as sources of bioactive chemicals. In recent years, there has been a surge in interest in investigating the possibilities of plant extracts in a variety of disciplines, including medicine, cosmetics, and food. This abstract presents an up-to-date assessment of methods for extracting, isolating, and identifying bioactive chemicals from plant extracts, highlighting advances and problems in this field. The first stage in acquiring bioactive chemicals from plant sources is extraction. Maceration, infusion, decoction, solvent extraction, supercritical fluid extraction, and microwave-assisted extraction are among the extraction procedures used. These approaches strive to extract the target molecules as efficiently as possible while keeping their chemical integrity and bioactivity.

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Susa, Francesca, e Roberto Pisano. "Advances in Ascorbic Acid (Vitamin C) Manufacturing: Green Extraction Techniques from Natural Sources". Processes 11, n.º 11 (6 de novembro de 2023): 3167. http://dx.doi.org/10.3390/pr11113167.

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Ascorbic acid (AA), or vitamin C, is one of the most important vitamins consumed through the diet due to its critical role in many biological processes. Although the human body cannot synthesize it, AA is essential in maintaining healthy bodily structure, acting as a cofactor of many enzymes involved in collagen synthesis and an efficient immune system. At the same time, AA is used in the cosmetic field for its antioxidant and antipigmentary properties, in the food industry as additive, and in chemical synthesis as reducing agent. AA can be chemically synthesized, produced by the oxidative fermentation of bacteria, or extracted from natural sources. This review addresses the most recent developments in its manufacture, including techniques for extracting vitamin C from plants, fruits, vegetables, algae, and leaves, and focusing on the most commonly used green methods, i.e., ultrasound-assisted extraction, microwave-assisted extraction, pressurized liquid extraction, and supercritical fluid extraction. These methods are based on mild extraction conditions, environmentally friendly solvents, low time, cost, and energy consumption. In contrast, their extraction yields are comparable to or even higher than those of conventional methods.

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Lu, Meng-Shan, Long-Li Lai e Yung-Pin Tsai. "COMPARISON OF OPTIMUM CONDITIONS WHEN EXTRACTING PHAS FROM DIFFERENT WASTE SLUDGE SOURCES". Journal of Environmental Engineering and Landscape Management 26, n.º 3 (9 de outubro de 2018): 190–94. http://dx.doi.org/10.3846/16486897.2017.1411271.

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Biological wastewater treatment plants produce great amounts of sludge daily. It is a very big loading (cost) for treating the waste sludge. Polyhydroxyalkanoates are a family of polyhydroxyesters. The technologies of extracting PHAs from wasted sewage sludges of municipal wastewater, fermentation industry and husbandry were developed in the study. In the NaOCl/SDS extraction technology, the concentration of NaOCl and liquid-solid ratio are two essential factors directly influencing extraction efficiency. The experimental results verified under the optimal conditions for extracting PHAs, the content of recovered PHAs was 44.2±0.89 mgPHA/gVSS and the purity of recovered PHAs was >99.5 wt% for the waste sludge from municipal wastewater treatment plants. For fermentation industry sludge, under the adequate extraction conditions for PHAs recovery, the content and purity of recovered PHAs were 18.8±0.66 mgPHA/gVSS and 50.6±6.83 wt%, respectively. For husbandry sludge, the content and purity of recovered PHAs were 33.7±0.16 mgPHA/gVSS and 76.7±5.2 wt%, respectively.

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Mais fontes

Teses / dissertações sobre o assunto "Extraction des sources"

González-Valentín, Karen M. (Karen Mercedes) 1978. "Extraction of variation sources due to layout practices". Thesis, Massachusetts Institute of Technology, 2002. http://hdl.handle.net/1721.1/87206.

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Thesis (S.M.)--Massachusetts Institute of Technology, Dept. of Electrical Engineering and Computer Science, 2002.
Includes bibliographical references (p. 97).
by Karen M. González-Valentín.
S.M.

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Yankova-Doseva, Milena. "TERMS - Text Extraction from Redundant and Multiple Sources". Thesis, University of Sheffield, 2010. http://etheses.whiterose.ac.uk/933/.

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In this work we present our approach to the identity resolution problem: discovering references to one and the same object that come from different sources. Solving this problem is important for a number of different communities (e.g. Database, NLP and Semantic Web) that process heterogeneous data where variations of the same objects are referenced in different formats (e.g. textual documents, web pages, database records, ontologies etc.). Identity resolution aims at creating a single view into the data where different facts are interlinked and incompleteness is remedied. We propose a four-step approach that starts with schema alignment of incoming data sources. As a second step - candidate selection - we discard those entities that are totally different from those that they are compared to. Next the main evidence for identity of two entities comes from applying similarity measures comparing their attribute values. The last step in the identity resolution process is data fusion or merging entities found to be identical into a single object. The principal novel contribution of our solution is the use of a rich semantic knowledge representation that allows for flexible and unified interpretation during the resolution process. Thus we are not restricted in the type of information that can be processed (although we have focussed our work on problems relating to information extracted from text). We report the implementation of these four steps in an IDentity Resolution Framework (IDRF) and their application to two use-cases. We propose a rule based approach for customisation in each step and introduce logical operators and their interpretation during the process. Our final evaluation shows that this approach facilitates high accuracy in resolving identity.

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Leouffre, Marc. "Extraction de sources d'électromyogrammes et évaluation des tensions musculaires". Thesis, Grenoble, 2014. http://www.theses.fr/2014GRENT009/document.

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L'évaluation des tensions musculaires chez l'Homme dans les sciences du mouvement et les études posturales présente un grand intérêt pour le sport, la santé ou encore l'ergonomie. La biomécanique s'intéresse tout particulièrement à ces problèmes utilise la cinématique inverse pour recalculer, à partir de mesures physiques externes, les tensions musculaires internes. Le verrou scientifique principal de cette technique est la redondance musculaire, propre au vivant. En effet les actionneurs (muscles) sont plus nombreux que les degrés de liberté à contrôler. Les problèmes de cinématique inverse sont sous-déterminés, ils présentent plus d'inconnues que d'équations, et nécessitent l'usage de procédures d'optimisation. Dans ce contexte l'usage de l'électromyographie (EMG), signal électro-physiologique mesurable à la surface de la peau et témoin de l'activité musculaire, peut donner une idée de l'activité des muscles sous-jacents. La connaissance de l'activité des muscles permettrait d'introduire de l'information supplémentaire dans cette méthodologie inverse afin d'améliorer l'estimation des tensions musculaires réelles au cours de mouvements ou dans une posture donnée. De plus certaines applications ne permettent pas ou peu l'enregistrement de forces ou positions articulaires externes qui nécessitent un appareillage conséquent et rendent difficile l'étude de situations de la vie courante. L'électromyographie est dans un tel contexte une mesure non-invasive et peu encombrante, facilement réalisable. Elle a cependant elle aussi ses propres verrous scientifiques. L'EMG de surface sur de petits muscles très rapprochés comme les nombreux muscles des avant-bras peut être sujette à ce qui est communément appelé « cross-talk » ; la contamination croisée des voies. Ce cross-talk est le résultat de la propagation des signaux musculaires sur plusieurs voies simultanément, si bien qu'il est compliqué d'associer l'activité d'un muscle à une unique voie EMG. Le traitement numérique du signal dispose d'outils permettant, dans certaines conditions, de retrouver des sources inconnues mélangées sur plusieurs capteurs. Ainsi la séparation de sources peut être utilisée sur des signaux EMG afin de retrouver de meilleures estimations des signaux sources reflétant plus fidèlement l'activité de muscles sans l'effet du cross-talk. Ce travail de thèse montre dans un premier temps l'intérêt de l'EMG dans l'étude de l'utilisation d'un prototype d'interface homme-machine novateur. L'EMG permet en particulier de mettre en évidence la présence forte de cocontraction musculaire permettant de stabiliser les articulations pour permettre un contrôle précis du dispositif. En outre des perspectives d'analyse plus fines seraient envisageables en utilisant des techniques de séparation de sources performantes en électromyographie. Dans un second temps l'accent est mis sur l'étude des conditions expérimentales précises permettant l'utilisation des techniques de séparation de sources en contexte linéaire instantané en électromyographie de surface. L'hypothèse d'instantanéité du mélange des sources en particulier est étudiée et sa validité est vérifiée sur des signaux réels. Enfin une solution d'amélioration de la robustesse de la séparation de sources à l'hypothèse de l'instantanéité est proposée. Celle-ci repose sur la factorisation en matrices non-négatives (NMF) des enveloppes des signaux EMG
Evaluation of muscle tensions in movement and gait sciences is of great interest in the fields of sports, health or ergonomics. Biomechanics in particular has been looking forward to solving these problems and developed the use of inverse kinematics to compute internal muscle tensions from external physical measures. Muscular redundancy remains however a complex issue, there are more muscles than degrees of freedom and thus more unknown variables which makes inverse kinematics an under-determined problem needing optimization techniques to be solved. In this context using electromyography (EMG), an electro-physiological signal that can be measured on the skin surface, gives an idea of underlying muscle activities. Knowing muscle activities could be additional information to feed the optimization procedures with and could help improving accuracy of estimated muscle tensions during real gestures or gait situation. There are even situations in which measuring external physical variables like forces, positions or accelerations is not feasible because it might require equipment incompatible with the object of the study. It is often the case in ergonomics when equipping the object of the study with sensors is either too expensive or physically too cumbersome. In such cases EMG can become very handy as a non-invasive measure that does not require the environment to be equipped with other sensors. EMG however has its own limits, surface EMG on small and closely located muscles like muscles of the forearm can be subject to “cross-talk”. Cross-talk is the cross contamination of several sensors it is the result of signal propagation of more than one muscle on one sensor. In presence of cross-talk it is not possible to associate an EMG sensor with a given muscle. There are signal processing techniques dealing with this kind of problem. Source separation techniques allow estimation of unknown sources from several sensors recording mixtures of these sources. Applying source separation techniques on EMG can provide EMG source estimations reflecting individual muscle activities without the effect of cross-talk. First the benefits of using surface EMG during an ergonomics study of an innovative human-computer interface are shown. EMG pointed out a relatively high level of muscle co-contraction that can be explained by the need to stabilize the joints for a more accurate control of the device. It seems legitimate to think that using source separation techniques would provide signals that better represent single muscle activities and these would improve the quality of this study. Then the precise experimental conditions for linear instantaneous source separation techniques to work are studied. Validity of the instantaneity hypothesis in particular is tested on real surface EMG signals and its strong dependency on relative sensor locations is shown. Finally a method to improve robustness of linear instantaneous source separation versus instantaneity hypothesis is proposed. This method relies on non-negative matrix factorization of EMG signal envelopes

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Dumitrescu, Stefan Daniel. "L' extraction d'information des sources de données non structurées et semi-structurées". Toulouse 3, 2011. http://thesesups.ups-tlse.fr/1555/.

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L'objectif de la thèse: Dans le contexte des dépôts de connaissances de grandes dimensions récemment apparues, on exige l'investigation de nouvelles méthodes innovatrices pour résoudre certains problèmes dans le domaine de l'Extraction de l'Information (EI), tout comme dans d'autres sous-domaines apparentés. La thèse débute par un tour d'ensemble dans le domaine de l'Extraction de l'Information, tout en se concentrant sur le problème de l'identification des entités dans des textes en langage naturel. Cela constitue une démarche nécessaire pour tout système EI. L'apparition des dépôts de connaissances de grandes dimensions permet le traitement des sous-problèmes de désambigüisation au Niveau du Sens (WSD) et La Reconnaissance des Entités dénommées (NER) d'une manière unifiée. Le premier système implémenté dans cette thèse identifie les entités (les noms communs et les noms propres) dans un texte libre et les associe à des entités dans une ontologie, pratiquement, tout en les désambigüisant. Un deuxième système implémenté, inspiré par l'information sémantique contenue dans les ontologies, essaie, également, l'utilisation d'une nouvelle méthode pour la solution du problème classique de classement de texte, obtenant de bons résultats
Thesis objective: In the context of recently developed large scale knowledge sources (general ontologies), investigate possible new approaches to major areas of Information Extraction (IE) and related fields. The thesis overviews the field of Information Extraction and focuses on the task of entity recognition in natural language texts, a required step for any IE system. Given the availability of large knowledge resources in the form of semantic graphs, an approach that treats the sub-tasks of Word Sense Disambiguation and Named Entity Recognition in a unified manner is possible. The first implemented system using this approach recognizes entities (words, both common and proper nouns) from free text and assigns them ontological classes, effectively disambiguating them. A second implemented system, inspired by the semantic information contained in the ontologies, also attempts a new approach to the classic problem of text classification, showing good results

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Horton, Bryan. "Rotational motion of pendula systems for wave energy extraction". Thesis, Available from the University of Aberdeen Library and Historic Collections Digital Resources, 2009. http://digitool.abdn.ac.uk:80/webclient/DeliveryManager?application=DIGITOOL-3&owner=resourcediscovery&custom_att_2=simple_viewer&pid=25873.

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Ferreira, Lage Sandra. "The neurotoxin β-N-methylamino-L-alanine (BMAA) : Sources, bioaccumulation and extraction procedures". Doctoral thesis, Stockholms universitet, Institutionen för ekologi, miljö och botanik, 2016. http://urn.kb.se/resolve?urn=urn:nbn:se:su:diva-132142.

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β-methylamino-L-alanine (BMAA) is a neurotoxin linked to neurodegeneration, which is manifested in the devastating human diseases amyotrophic lateral sclerosis, Alzheimer’s and Parkinson’s disease. This neurotoxin is known to be produced by almost all tested species within the cyanobacterial phylum including free living as well as the symbiotic strains. The global distribution of the BMAA producers ranges from a terrestrial ecosystem on the Island of Guam in the Pacific Ocean to an aquatic ecosystem in Northern Europe, the Baltic Sea, where annually massive surface blooms occur. BMAA had been shown to accumulate in the Baltic Sea food web, with highest levels in the bottom dwelling fish-species as well as in mollusks. One of the aims of this thesis was to test the bottom-dwelling bioaccumulation hypothesis by using a larger number of samples allowing a statistical evaluation. Hence, a large set of fish individuals from the lake Finjasjön, were caught and the BMAA concentrations in different tissues were related to the season of catching, fish gender, total weight and species. The results reveal that fish total weight and fish species were positively correlated with BMAA concentration in the fish brain. Therefore, significantly higher concentrations of BMAA in the brain were detected in plankti-benthivorous fish species and heavier (potentially older) individuals. Another goal was to investigate the potential production of BMAA by other phytoplankton organisms. Therefore, diatom cultures were investigated and confirmed to produce BMAA, even in higher concentrations than cyanobacteria. All diatom cultures studied during this thesis work were show to contain BMAA, as well as one dinoflagellate species. This might imply that the environmental spread of BMAA in aquatic ecosystems is even higher than previously thought. Earlier reports on the concentration of BMAA in different organisms have shown highly variable results and the methods used for quantification have been intensively discussed in the scientific community. In the most recent studies, liquid chromatography-tandem mass spectrometry (LC-MS/MS) has become the instrument of choice, due to its high sensitivity and selectivity. Even so, different studies show quite variable concentrations of BMAA. In this thesis, three of the most common BMAA extraction protocols were evaluated in order to find out if the extraction could be one of the sources of variability. It was found that the method involving precipitation of proteins using trichloroacetic acid gave the best performance, complying with all in-house validation criteria. However, extractions of diatom and cyanobacteria cultures with this validated method and quantified using LC-MS/MS still resulted in variable BMAA concentrations, which suggest that also biological reasons contribute to the discrepancies. The current knowledge on the environmental factors that can induce or reduce BMAA production is still limited. In cyanobacteria, production of BMAA was earlier shown to be negative correlated with nitrogen availability – both in laboratory cultures as well as in natural populations. Based on this observation, it was suggested that in unicellular non-diazotrophic cyanobacteria, BMAA might take part in nitrogen metabolism. In order to find out if BMAA has a similar role in diatoms, BMAA was added to two diatom species in culture, in concentrations corresponding to those earlier found in the diatoms. The results suggest that BMAA might induce a nitrogen starvation signal in diatoms, as was earlier observed in cyanobacteria. However, diatoms recover shortly by the extracellular presence of excreted ammonia. Thus, also in diatoms, BMAA might be involved in the nitrogen balance in the cell.

At the time of the doctoral defense, the following paper was unpublished and had a status as follows: Paper 4: Manuscript.

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Xu, Xu. "Nonlinear dynamics of parametric pendulum for wave energy extraction". Thesis, University of Aberdeen, 2005. http://digitool.abdn.ac.uk:80/webclient/DeliveryManager?pid=189414.

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A new concept, extracting energy from sea waves by parametric pendulor, has been explored in this project. It is based on the conversion of vertical oscillations to rotational motion by means of a parametrically-excited pendulor, i.e. a pendulum operating in rotational mode. The main advantage of this concept lies in a direct conversion from vertical oscillations to rotations of the pendulum pivot. This thesis, firstly, reviewed a number of well established linear and nonlinear theories of sea waves and Airy’s sea wave model has been used in the modelling of the sea waves and a parametric pendulum excited by sea waves. The third or fifth order Stokes’s models can be potentially implemented in the future studies. The equation of motion obtained for a parametric pendulum excited by sea waves has the same form as for a simple parametrically-excited pendulum. Then, to deepen the fundamental understanding, an extensive theoretical analysis has been conducted on a parametrically-excited pendulum by using both numerical and analytical methods. The numerical investigations focused on the bifurcation scenarios and resonance structures, particularly, for the rotational motions. Analytical analysis of the system has been performed by applying the perturbation techniques. The approximate solutions, resonance boundary and existing boundary of rotations have been obtained with a good correspondence to numerical results. The experimental study has been carried out by exploring oscillations, rotations and chaotic motions of the pendulum.

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Albezzawy, Muhammad Nabil Mustafa. "Advanced signal processing methods for source identification using references". Electronic Thesis or Diss., Lyon, INSA, 2024. http://www.theses.fr/2024ISAL0074.

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Les techniques de référence à rang réduit sont couramment employées pour résoudre les problèmes d’extraction de source et de resynchronisation de champs physiques, lorsque le nombre de références dépasse celui des sources incohérentes. Dans ce cas, la matrice croisée-spectrale devient mal conditionnée, rendant la solution des moindres carrés invalide. Bien que la décomposition en valeurs singulières tronquée (DVST) soit utilisée pour résoudre ce problème, elle n'est valable que pour un bruit scalaire sur les références. De plus, il est difficile de définir un seuil de troncature lorsque les valeurs singulières diminuent progressivement. Cette thèse propose une solution nommée technique de référence maximale-coherent (RMC), basée sur la recherche d’un ensemble de références virtuelles maximales correlées avec les mesures de champ. Cette technique est optimale, surtout en présence d’un bruit corrélé sur la référence. Cependant, elle nécessite également une troncature des valeurs propres, exigeant la connaissance ou l’estimation préalable du nombre de sources incohérentes, un problème inverse mal posé et peu étudié. La thèse présente trois méthodes d’énumération de sources applicables à toutes les techniques de référence : un test du rapport de vraisemblance contre le modèle saturé, une technique de bootstrap paramétrique et une approche de validation croisée. Une étude comparative basée sur des données numériques et expérimentales montre deux résultats importants. D'abord, le nombre de fenêtres spectrales utilisées affecte grandement la performance des trois méthodes, qui se comportent différemment selon ce nombre. Ensuite, le bootstrap paramétrique s’avère être la meilleure méthode en termes de précision et de robustesse par rapport au nombre de fenêtres utilisées. Enfin, la technique RMC accompagnée de bootstrap a été utilisée pour l’extraction de source et la resynchronisation de données réelles provenant d’expériences en laboratoire et d’un moteur électrique, fournissant de meilleurs résultats que la solution des moindres carrés et la DVST dans les mêmes conditions
Rank-reduced reference/coherence techniques based on the use of references, i.e. fixed sensors, are widely used to solve the two equivalent problems of source extraction and resynchronization encountered during remote sensing of physical fields, when the number of references surpasses the number of incoherent sources. In such case, the cross-spectral matrix (CSM) becomes ill-conditioned, resulting in the invalidity of the least squares LS solution. Although the truncated singular value decomposition (TSVD) was successfully applied in the literature to solve this problem, its validity is limited only to the case of scalar noise on the references. It is also very difficult to define a threshold, for truncation, when the singular values are gradually decreasing. This thesis proposes a solution based on finding a set of virtual references that is maximally correlated with the field measurements, named the maximally-coherent reference (MCR) Technique. This solution is optimal, especially, in the case of correlated noise on the reference, where TSVD fails. However the technique also includes an eigenvalue truncation step, similar to the one required for the TSVD, which necessitates a priori knowledge or the estimation of the number of incoherent sources, i.e. source enumeration, which is an ill-posed inverse problem, insufficiently investigated in the literature within the framework of reference techniques. In this thesis, after providing a unified formalism for all the reference techniques in the literature, three alternative source enumeration methods, applicable to all the reference techniques, were presented namely; a direct likelihood ratio test (LRT) against the saturated model, a parametric bootstrap technique and a cross-validation approach. A comparative study is performed among the three methods, based on simulated numerical data, real sound experimental data, and real electrical motor data. The results showed two important outcomes. The first is that the number of snapshots (spectral windows), used in the spectral analysis, greatly affects the performance of the three methods, and that, they behave differently for the same number of used snapshots. The second is that parametric bootstrapping turned out to be the best method in terms of both estimation accuracy and robustness with regard to the used number of snapshots. Finally, the MCR technique accompanied with bootstrapping was employed for source extraction and resynchronization of real data from laboratory experiments, and an e-motor, and it returned better results than the LS solution and the TSVD when employed for the same purpose

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Syed, Ali Asgher. "Hole extraction layer/perovskite interfacial modification for high performing inverted planar perovskite solar cells". HKBU Institutional Repository, 2018. https://repository.hkbu.edu.hk/etd_oa/553.

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Organo-metallic halide perovskite solar cells (PSCs) are considered as a promising alternative photovoltaic technology due to the advantages of low-cost solution fabrication capability and high power conversion efficiency (PCE). PSCs can be made using a conventional (n-i-p) structure and an inverted (p-i-n) configuration. PCE of the conventional p-i-n type PSCs is slightly higher than that of the inverted n-i-p type PSCs. However, the TiO2 electron transporting layer adopted in the conventional PSCs is formed at a high sintering temperature of >450 °C. The TiO2 electron transporting layer limits the application of conventional PSCs using flexible substrates that are not compatible with the high processing temperature. The hole extraction layer (HEL) in the inverted p-i-n type PSCs can be prepared by low-temperature solution fabrication processes, which can be adopted for achieving high performance large area flexible solar cells at a low cost. Inverted PSCs with a PCE range from 10 to 20% have been reported over the past few years. In comparison with the progresses of other photovoltaic technologies, the rapid enhancement in PCE of the PSCs offers an attractive option for commercial viability. The aim of this PhD project is to study the origin of the improvement in the performance of solution-processable inverted PSCs. The surface morphological and electronic properties of the HEL are crucial for the growth of the perovskite active layer and hence the performance of the inverted PSCs. Enhancement in short circuit current density (Jsc), reduced loss in open circuit voltage (Voc), improvement in cha Organo-metallic halide perovskite solar cells (PSCs) are considered as a promising alternative photovoltaic technology due to the advantages of low-cost solution fabrication capability and high power conversion efficiency (PCE). PSCs can be made using a conventional (n-i-p) structure and an inverted (p-i-n) configuration. PCE of the conventional p-i-n type PSCs is slightly higher than that of the inverted n-i-p type PSCs. However, the TiO2 electron transporting layer adopted in the conventional PSCs is formed at a high sintering temperature of >450 °C. The TiO2 electron transporting layer limits the application of conventional PSCs using flexible substrates that are not compatible with the high processing temperature. The hole extraction layer (HEL) in the inverted p-i-n type PSCs can be prepared by low-temperature solution fabrication processes, which can be adopted for achieving high performance large area flexible solar cells at a low cost. Inverted PSCs with a PCE range from 10 to 20% have been reported over the past few years. In comparison with the progresses of other photovoltaic technologies, the rapid enhancement in PCE of the PSCs offers an attractive option for commercial viability. The aim of this PhD project is to study the origin of the improvement in the performance of solution-processable inverted PSCs. The surface morphological and electronic properties of the HEL are crucial for the growth of the perovskite active layer and hence the performance of the inverted PSCs. Enhancement in short circuit current density (Jsc), reduced loss in open circuit voltage (Voc), improvement in charge collection efficiency (ηcc) through suppression of charge recombination were investigated systematically via controlled growth of the perovskite active layer in solution-processed inverted PSCs. Poly (3,4-ethylenedioxythiophene): poly (4-styrenesulfonate) (PEDOT:PSS) is one of the widely used solution processable conductive materials for hole transporting in different optoelectronic devices. PEDOT:PSS HEL also is a perfect electron blocking layer due to its high LUMO level. However, it has been reported that PEDOT:PSS HEL is related to the deterioration in the stability of PSCs due to its acidic and hygroscopic nature. Modification of PEDOT:PSS using solvent additives or incorporating metallic oxide nanoparticles for improving the processability and the performance of the inverted PSCs were reported. This work has been focused primary on realizing the controlled growth of perovskite active layer via HEL/perovskite interfacial modification using sodium citrate-treated PEDOT:PSS HEL and WO3-PEDOT:PSS composite HEL. Apart from investigating the properties of the modified PEDOT:PSS HELs, the purpose of the work is to improve the understanding of the effect of modified HEL on the growth of the perovskite layer, revealing the charge recombination processes under different operation conditions, analyzing change extraction probability, and thereby improving the overall performance of the PSCs. PCE of >11.30% was achieved for PSCs with a sodium citrate-modified PEDOT:PSS HEL, which is >20% higher than that of a structurally identical control device having a pristine PEDOT:PSS HEL (9.16%). The incident photon to current efficiency (IPCE) and light intensity-dependent J-V measurements reveal that the use of the sodium citrate-modified PEDOT:PSS HEL helps to boost the performance of the inverted PSCs in two ways: (1) it improves the processability of perovskite active layer on HEL, and (2) it enables to enhance the charge extraction efficiency at the HEL/perovskite interface. The suppression of charge recombination in the PSCs with a modified HEL also was examined using photocurrent-effective voltage (Jph-Veff) and transient photocurrent (TPC) measurements. Morphological and structural properties of the perovskite layers were investigated using the scanning electron microscope (SEM) and X-ray diffraction (XRD) measurements. The results reveal that high quality perovskite active layer on the modified HEL was attained forming complete perovskite phase. The surface electronic properties of the modified PEDOT:PSS and pristine PEDOT:PSS layers were studied using X-ray photoelectron spectroscopy (XPS) and ultraviolet photoelectron spectroscopy (UPS) measurements. XPS results reveal that treatment of sodium citrate partially removes the PSS unit in the PEDOT:PSS, resulting in an increase in the ratio of PEDOT to PSS from 0.197 for a treated PEDOT:PSS HEL to that of 0.108 for the pristine PEDOT:PSS HEL. UPS measurements also show that there is an observable reduction in the work function of the modified HEL, implying that sodium citrate-modified PEDOT:PSS HEL possesses an improved electron blocking capability, which is beneficial for efficient operation of the inverted PSCs.;The performance enhancement in MAPbI3-based PSCs with a tungsten oxide (WO3)-PEDOT:PSS composite HEL also was analyzed. The uniform composite WO3-PEDOT:PSS HEL was formed on indium tin oxide (ITO) surface by solution fabrication process. The morphological and surface electronic properties of WO3-PEDOT:PSS composite film were examined using AFM, XPS, UPS and Raman Spectroscopy. SEM images reveal that the perovskite films grown on the composite HEL had a full coverage without observable pin holes. XRD results show clearly that no residual of lead iodide phase was observed, suggesting a complete perovskite phase was obtained for the perovskite active layer grown on the composite HEL. The volume ratio of WO3 to PEDOT:PSS of 1:0.25 was optimized for achieving enhanced current density and Voc in the PSCs. It is demonstrated clearly that the use of the WO3-PEDOT:PSS composite HEL helps to improve the charge collection probability through suppression of the charge recombination at the MAPbI3/composite HEL interface. The charge extraction efficiency at the perovskite/PEDOT:PSS and perovskite/composite HEL interfaces were investigated by analyzing the PL quenching efficiency of the MAPbI3 active layer. It is shown that the PL efficiency quenching at the MAPbI3/composite HEL samples is one order of magnitude higher than that measured for the perovskite/pristine PEDOT:PSS sample, suggesting an enhanced hole extraction probability at the MAPbI3/composite HEL interface. The combined effects of improved perovskite crystal growth and enhanced charge extraction capabilities result in the inverted PSCs with a PCE of 12.65%, which is 22% higher than that of a structurally identical control device (10.39%). The use of the WO3-PEDOT:PSS composite HEL also benefits the efficient operation of the PSCs, demonstrated in the stability test, as compared to that of the control cell under the same aging conditions. With the progresses made in improving the performance of MAPbI3-based PSCs, the research was extended to study the performance of efficient PSCs with mixed halide of MA0.7FA0.3Pb (I0.9Br0.1)3. The effect of the annealing temperature on the growth of the mixed MA0.7FA0.3Pb (I0.9Br0.1)3 perovskite active layer was analyzed. It was found that the optimal growth of the mixed perovskite active layer occurred at an annealing temperature of 100°C. UPS results reveal that the ionization potential of 5.76 eV measured for the mixed cation perovskite is lower than that of MAPbI3-based single cation perovskite layer (5.85 eV), while the corresponding electron affinity of the mixed perovskite was 4.28 eV and that for the MAPbI3 layer was 4.18 eV, respectively. The changes in the bandgap and the energy levels of the MA0.7FA0.3Pb (I0.9Br0.1)3 and MAPbI3 active layers were examined using UV-vis absorption spectroscopy and UPS measurements. Compared to the MAPbI3-based control cell, a 23% increase in Jsc, a 15% increase in Voc and an overall 25% increase in PCE for the MA0.7FA0.3Pb (I0.9Br0.1)3 were achieved as compared to that of the MAPbI3-based PSCs. An obvious improvement in charge collection efficiency in MA0.7FA0.3Pb (I0.9Br0.1)3-based PSCs operated at different Veff was clearly manifested by the light intensity dependent J-V characteristic measurements. PL quenching efficiency also shows the charge transfer between MA0.7FA0.3Pb (I0.9Br0.1)3 and PEDOT:PSS HEL is one order of magnitude higher as compare to that in the MAPbI3-based PSCs, suggesting the formation of improved interfacial properties at the MA0.7FA0.3Pb (I0.9Br0.1)3/HEL interface. The impact of incorporating mixed MA0.7FA0.3Pb (I0.9Br0.1)3 perovskite active layer on PCE and the stability of the PSCs was further studied using a combination of TPC measurement and aging test. The stability of MA0.7FA0.3Pb (I0.9Br0.1)3- and MAPbI3-based PSCs with respect to the aging time was monitored for a period of >2 months. The MA0.7FA0.3Pb (I0.9Br0.1)3-based PSCs are more stable compared to the MAPbI3-based PSCs aged under the same conditions. The aging test supports the findings made with the TPC and light intensity dependent J-V measurements. It shows that the improved interfacial quality at the perovskite/HEL and the enhanced charge extraction capability are favorable for efficient and stable operation of MA0.7FA0.3Pb (I0.9Br0.1)3-based PSCs.

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Zaman, Tauhid R. "Information extraction with network centralities : finding rumor sources, measuring influence, and learning community structure". Thesis, Massachusetts Institute of Technology, 2011. http://hdl.handle.net/1721.1/70410.

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Thesis (Ph. D.)--Massachusetts Institute of Technology, Dept. of Electrical Engineering and Computer Science, 2011.
Cataloged from PDF version of thesis.
Includes bibliographical references (p. 193-197).
Network centrality is a function that takes a network graph as input and assigns a score to each node. In this thesis, we investigate the potential of network centralities for addressing inference questions arising in the context of large-scale networked data. These questions are particularly challenging because they require algorithms which are extremely fast and simple so as to be scalable, while at the same time they must perform well. It is this tension between scalability and performance that this thesis aims to resolve by using appropriate network centralities. Specifically, we solve three important network inference problems using network centrality: finding rumor sources, measuring influence, and learning community structure. We develop a new network centrality called rumor centrality to find rumor sources in networks. We give a linear time algorithm for calculating rumor centrality, demonstrating its practicality for large networks. Rumor centrality is proven to be an exact maximum likelihood rumor source estimator for random regular graphs (under an appropriate probabilistic rumor spreading model). For a wide class of networks and rumor spreading models, we prove that it is an accurate estimator. To establish the universality of rumor centrality as a source estimator, we utilize techniques from the classical theory of generalized Polya's urns and branching processes. Next we use rumor centrality to measure influence in Twitter. We develop an influence score based on rumor centrality which can be calculated in linear time. To justify the use of rumor centrality as the influence score, we use it to develop a new network growth model called topological network growth. We find that this model accurately reproduces two important features observed empirically in Twitter retweet networks: a power-law degree distribution and a superstar node with very high degree. Using these results, we argue that rumor centrality is correctly quantifying the influence of users on Twitter. These scores form the basis of a dynamic influence tracking engine called Trumor which allows one to measure the influence of users in Twitter or more generally in any networked data. Finally we investigate learning the community structure of a network. Using arguments based on social interactions, we determine that the network centrality known as degree centrality can be used to detect communities. We use this to develop the leader-follower algorithm (LFA) which can learn the overlapping community structure in networks. The LFA runtime is linear in the network size. It is also non-parametric, in the sense that it can learn both the number and size of communities naturally from the network structure without requiring any input parameters. We prove that it is very robust and learns accurate community structure for a broad class of networks. We find that the LFA does a better job of learning community structure on real social and biological networks than more common algorithms such as spectral clustering.
by Tauhid R. Zaman.
Ph.D.

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Livros sobre o assunto "Extraction des sources"

Gabizon, Ariel. Deterministic Extraction from Weak Random Sources. Berlin, Heidelberg: Springer Berlin Heidelberg, 2011. http://dx.doi.org/10.1007/978-3-642-14903-0.

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Harbuck, D. D. Gallium and germanium recovery from domestic sources. Washington, D.C: U.S. Dept. of the Interior, Bureau of Mines, 1992.

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Harbuck, D. D. Gallium and germanium recovery from domestic sources. Washington, D.C: U.S. Dept. of the Interior, Bureau of Mines, 1992.

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Ursino, Domenico. Extraction and Exploitation of Intensional Knowledge from Heterogeneous Information Sources. Berlin, Heidelberg: Springer Berlin Heidelberg, 2002. http://dx.doi.org/10.1007/3-540-70735-2.

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Wight, G. J., fl. 1862., ed. Map and guide to the Cariboo gold mines of British Columbia: By Jules H. Féry, C.L.C., with notes, observations, directions, and information, gathered from official and other authentic sources by G.J. Wight, counselor at law. San Francisco: F. Truette, 1987.

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Wight, G. J., fl. 1862., ed. Map and guide to the Cariboo gold mines of British Columbia: By Jules H. Féry, C.L.C., with notes, observations, directions, and information, gathered from official and other authentic sources by C.J. Wight, counselor at law. San Francisco: F. Truette, 1987.

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Société des archives historiques de la région de L'Amiante, ed. 100 ans d'histoire sur les mines d'amiante à travers les archives, 1901-2000. Montréal: Éditions Histoire Québec, 2007.

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Poibeau, Thierry, Horacio Saggion, Jakub Piskorski e Roman Yangarber, eds. Multi-source, Multilingual Information Extraction and Summarization. Berlin, Heidelberg: Springer Berlin Heidelberg, 2013. http://dx.doi.org/10.1007/978-3-642-28569-1.

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1803-1877, Douglas James Sir, Lytton, Edward George Earle Lytton-Bulwer, Baron, 1803-1873., Newcastle, Henry Pelham Fiennes Pelham Clinton, Duke of, 1811-1864., British Columbia. Governor (1858-1864 : Douglas) e Great Britain Colonial Office, eds. Papers relative to the affairs of British Columbia. London: G.E. Eyre and W. Spottiswoode, 2000.

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Wisniak, Jaime. Liquid-liquid equilibrium and extraction: A literature source book. Amsterdam: Elsevier, 1985.

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Capítulos de livros sobre o assunto "Extraction des sources"

Hollinger, Ralph. "Ion Extraction". In The Physics and Technology of Ion Sources, 61–86. Weinheim, FRG: Wiley-VCH Verlag GmbH & Co. KGaA, 2005. http://dx.doi.org/10.1002/3527603956.ch5.

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Singh, Jyotika. "Data Sources and Extraction". In Natural Language Processing in the Real World, 35–68. Boca Raton: Chapman and Hall/CRC, 2023. http://dx.doi.org/10.1201/9781003264774-2.

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Rivet, Bertrand, Leonardo T. Duarte e Christian Jutten. "Blind Extraction of Intermittent Sources". In Latent Variable Analysis and Signal Separation, 402–9. Berlin, Heidelberg: Springer Berlin Heidelberg, 2010. http://dx.doi.org/10.1007/978-3-642-15995-4_50.

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Unbehauen, Jörg, Sebastian Hellmann, Sören Auer e Claus Stadler. "Knowledge Extraction from Structured Sources". In Search Computing, 34–52. Berlin, Heidelberg: Springer Berlin Heidelberg, 2012. http://dx.doi.org/10.1007/978-3-642-34213-4_3.

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Hauser-Davis, Rachel Ann. "Titanium Sources and Extraction Processes". In Titanium, 6–10. Boca Raton: CRC Press, 2024. http://dx.doi.org/10.1201/9781003319245-3.

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Spädtke, Peter. "Computer Simulation of Extraction". In The Physics and Technology of Ion Sources, 41–60. Weinheim, FRG: Wiley-VCH Verlag GmbH & Co. KGaA, 2005. http://dx.doi.org/10.1002/3527603956.ch4.

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Dodis, Yevgeniy, Ariel Elbaz, Roberto Oliveira e Ran Raz. "Improved Randomness Extraction from Two Independent Sources". In Approximation, Randomization, and Combinatorial Optimization. Algorithms and Techniques, 334–44. Berlin, Heidelberg: Springer Berlin Heidelberg, 2004. http://dx.doi.org/10.1007/978-3-540-27821-4_30.

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Malhotra, Hitesh, Aditya Ashri, Rajeev K. Singla e Rupesh K. Gautam. "Eupatilin: Sources, Extraction, Derivatives, and Pharmacological Activity". In Handbook of Dietary Flavonoids, 1–50. Cham: Springer International Publishing, 2023. http://dx.doi.org/10.1007/978-3-030-94753-8_84-1.

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Mahajan, Palak, Parmjit S. Panesar e Manab Bandhu Bera. "Extraction Technology of Bioactive Compounds and Nutraceuticals: Factors Influencing its Extraction and Bioactivity". In Bioactive Compounds and Nutraceuticals from Dairy, Marine, and Nonconventional Sources, 61–100. New York: Apple Academic Press, 2024. http://dx.doi.org/10.1201/9781003452768-3.

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Ludwig, Philipp, Marcus Thiel e Andreas Nürnberger. "Unsupervised Extraction of Conceptual Keyphrases from Abstracts". In Semantic Keyword-Based Search on Structured Data Sources, 37–48. Cham: Springer International Publishing, 2017. http://dx.doi.org/10.1007/978-3-319-53640-8_4.

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Trabalhos de conferências sobre o assunto "Extraction des sources"

Zhao, Bo, Yanlin Deng, Keqiang Wang, Biao Hu, Hao Zhou, Haiyang Wang e Tianming Li. "Investigation on Multi-Port Radial Extraction S-Band Relativistic Magnetron". In 2024 Joint International Vacuum Electronics Conference and International Vacuum Electron Sources Conference (IVEC + IVESC), 1–2. IEEE, 2024. http://dx.doi.org/10.1109/ivecivesc60838.2024.10695001.

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Mourad, Nasser, e James P. Reilly. "Blind extraction of sparse sources". In 2010 IEEE International Conference on Acoustics, Speech and Signal Processing. IEEE, 2010. http://dx.doi.org/10.1109/icassp.2010.5496249.

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Ben-Menahem, Shahar, e David Yu. "A coax ring-sidearm power extraction design". In Pulsed RF sources for linear colliders. AIP, 1995. http://dx.doi.org/10.1063/1.48419.

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Tinschert, K. "Experiments on Beam Extraction from the CAPRICE ECRIS". In ELECTRON CYCLOTRON RESONANCE ION SOURCES: 16th International Workshop on ECR Ion Sources ECRIS'04. AIP, 2005. http://dx.doi.org/10.1063/1.1893411.

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Ghaderi, Foad, Bahador Makkiabadi, John G. McWhirter e Saeid Sanei. "Blind source extraction of cyclostationary sources with common cyclic frequencies". In 2010 IEEE International Conference on Acoustics, Speech and Signal Processing. IEEE, 2010. http://dx.doi.org/10.1109/icassp.2010.5495718.

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Tóth, Szabolcs, Huabao Cao, Mikhail Kalashnikov, vladimir chvykov e Karoly Osvay. "Cascaded Extraction OPCPA - A Highly Efficient Power Amplifier Design". In Compact EUV & X-ray Light Sources. Washington, D.C.: OSA, 2018. http://dx.doi.org/10.1364/euvxray.2018.jt5a.20.

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Robinson, J. "Data extraction from Web data sources". In Proceedings. 15th International Workshop on Database and Expert Systems Applications, 2004. IEEE, 2004. http://dx.doi.org/10.1109/dexa.2004.1333487.

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Yahaya, Nor, e Rosiza Buang. "Automated Metadata Extraction from Web Sources". In 2006 IEEE/WIC/ACM International Conference on Web Intelligence and Intelligent Agent Technology Workshops. IEEE, 2006. http://dx.doi.org/10.1109/wi-iatw.2006.49.

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Javidi, S., C. Cheong Took, C. Jahanchahi, N. Le Bihan e D. P. Mandic. "Blind extraction of improper quaternion sources". In ICASSP 2011 - 2011 IEEE International Conference on Acoustics, Speech and Signal Processing (ICASSP). IEEE, 2011. http://dx.doi.org/10.1109/icassp.2011.5947156.

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Cavenago, M. "Extraction layer models for negative ion sources". In FIFTH INTERNATIONAL SYMPOSIUM ON NEGATIVE IONS, BEAMS AND SOURCES (NIBS 2016). Author(s), 2017. http://dx.doi.org/10.1063/1.4995712.

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Relatórios de organizações sobre o assunto "Extraction des sources"

Skone, Timothy J. Natural Gas Extraction, Other Venting Point Sources. Office of Scientific and Technical Information (OSTI), janeiro de 2013. http://dx.doi.org/10.2172/1509091.

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Kamperschroer, J. H., L. R. Grisham, R. A. Newman, T. E. O`Connor, T. N. Stevenson, A. von Halle, M. D. Williams e K. E. Wright. Low Z impurity ion extraction from TFTR ion sources. Office of Scientific and Technical Information (OSTI), abril de 1993. http://dx.doi.org/10.2172/10144103.

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Kamperschroer, J. H., L. R. Grisham, R. A. Newman, T. E. O'Connor, T. N. Stevenson, A. von Halle, M. D. Williams e K. E. Wright. Low Z impurity ion extraction from TFTR ion sources. Office of Scientific and Technical Information (OSTI), abril de 1993. http://dx.doi.org/10.2172/6867280.

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Olsen, D. K., R. J. Raridon e J. H. Whealton. Results from a double Vlasov model for negative ion extraction from volume sources. Office of Scientific and Technical Information (OSTI), julho de 1998. http://dx.doi.org/10.2172/638208.

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Leece, A., e C. Jiang. A preliminary techno-economic assessment of lithium extraction from flowback and produced water from unconventional shale and tight hydrocarbon operations in Western Canada. Natural Resources Canada/CMSS/Information Management, 2023. http://dx.doi.org/10.4095/331879.

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In the path towards decarbonization, rechargeable lithium-ion batteries are critical for the widespread adoption of electric vehicles and renewable energy storage systems. To meet the growing demand for this mineral, various sources of lithium are being explored. This study evaluated the technical and economic feasibility of direct lithium extraction (DLE) from flowback and produced waters (FPW) of the Duvernay shale reservoir development near Fox Creek, Alberta and the Montney tight reservoir development in Northeast British Columbia using ion-exchange sorbents. Results indicate that lithium extraction from FPW using DLE technology is a viable option, with fluid pH, temperature, total suspended solids, and organic carbon affecting extraction efficiencies. In the assessment of Duvernay-based FPW fluids processed at a selected centralized facility, approximately 93 tonnes of lithium carbonate, or 105 tonnes of lithium hydroxide monohydrate could be produced annually, based on an average lithium content of 45.1 mg/L and a capacity of approximately 475,000 m3 per year. A discounted cash flow analysis determined the after-tax and royalty internal rate of return of 22% in the production of lithium carbonate (Li2CO3), and 38% in the production of lithium hydroxide monohydrate (LiOH·H2O) from the Duvernay development area. Comparatively, in the assessment of Montney brine fluids processed at a modelled centralized facility, approximately 117 tonnes of lithium carbonate or 134 tonnes of lithium hydroxide monohydrate could be produced annually, based on an average lithium content of 57.7 mg/L and a capacity of approximately 475,000 m3 per year. A discounted cash flow analysis determined the after-tax and royalty internal rate of return of 29% in the production of lithium carbonate and 48% in the production of lithium hydroxide monohydrate from the Dawson Creek Montney development area. These findings demonstrate the economic feasibility of extracting and refining lithium into battery-grade products from a novel source based on forecasted commodity prices and the development of a domestic battery supply chain system. Further investigation of DLE technology, a strategic resource sampling and analysis program, and investigation into the minimum scale of lithium extraction development are recommended.

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Crouch, Rebecca, Jared Smith, Bobbi Stromer, Christian Hubley, Samuel Beal, Guilherme Lotufo, Afrachanna Butler et al. Preparative, extraction, and analytical methods for simultaneous determination of legacy and insensitive munition (IM) constituents in aqueous, soil or sediment, and tissue matrices. Engineer Research and Development Center (U.S.), agosto de 2021. http://dx.doi.org/10.21079/11681/41480.

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No standard method exists for determining levels of insensitive munition (IM) compounds in environmental matrices. This project resulted in new methods of extraction, analytical separation and quantitation of 17 legacy and 7 IM compounds, daughter products of IM, and other munition compounds absent from USEPA Method 8330B. Extraction methods were developed for aqueous (direct-injection and solid-phase extraction [SPE]), soil, sediment, and tissue samples using laboratory-spiked samples. Aqueous methods were tested on 5 water sources, with 23 of 24 compounds recovered within DoD QSM Ver5.2 limits. New solvent extraction (SE) methods enabled recovery of all 24 compounds from 6 soils within QSM limits, and a majority of the 24 compounds were recovered at acceptable levels from 4 tissues types. A modified chromatographic treatment method removed analytical interferences from tissue extracts. Two orthogonal high-performance liquid chromatography-ultraviolet (HPLC-UV) separation methods, along with an HPLC–mass spectrometric (HPLC-MS) method, were developed. Implementing these new methods should reduce labor and supply costs by approximately 50%, requiring a single extraction and sample preparation, and 2 analyses rather than 4. These new methods will support environmental monitoring of IM and facilitate execution of risk-related studies to determine long-term effects of IM compounds.

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AlBakri, Aref, Auswaf Ahsan, Manoj Vengal, KR Ashir, Abdul Majeed e Hanan Siddiq. Antibiotic Prophylaxis before Invasive Dental Procedures for Patients at High-Risk of Infective Endocarditis. INPLASY - International Platform of Registered Systematic Review and Meta-analysis Protocols, julho de 2022. http://dx.doi.org/10.37766/inplasy2022.7.0011.

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Review question / Objective: The aim of the present systematic review and meta-analysis is to determine whether there is a genuine clinical need for Antibiotic Prophylaxis(AP) for the prevention of Infective Endocarditis(IE) in high-risk individuals (particularly those with demonstrable structural heart diseases or valve surgery) undergoing invasive dental procedures. Information sources: PubMed, Science Direct, British Dental Journal and Cochrane Register of Controlled Trials. Search terms used included various combinations of the following subject headings and title or abstract keywords – prophylactic antibiotics, antibiotic prophylaxis, antimicrobial, dentist, extraction, implant, infective endocarditis, or bacterial endocarditis.

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Zio, Enrico, e Nicola Pedroni. Uncertainty characterization in risk analysis for decision-making practice. Fondation pour une culture de sécurité industrielle, maio de 2012. http://dx.doi.org/10.57071/155chr.

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This document provides an overview of sources of uncertainty in probabilistic risk analysis. For each phase of the risk analysis process (system modeling, hazard identification, estimation of the probability and consequences of accident sequences, risk evaluation), the authors describe and classify the types of uncertainty that can arise. The document provides: a description of the risk assessment process, as used in hazardous industries such as nuclear power and offshore oil and gas extraction; a classification of sources of uncertainty (both epistemic and aleatory) and a description of techniques for uncertainty representation; a description of the different steps involved in a Probabilistic Risk Assessment (PRA) or Quantitative Risk Assessment (QRA), and an analysis of the types of uncertainty that can affect each of these steps; annexes giving an overview of a number of tools used during probabilistic risk assessment, including the HAZID technique, fault trees and event tree analysis.

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Kingston, A. W., C. Jiang, X. Wang e T. E. Hobbs. Chemical compositions of flowback and produced water from the Duvernay shale and Montney tight reservoir developments in Western Canada: potential for lithium resources from wastewater. Natural Resources Canada/CMSS/Information Management, 2023. http://dx.doi.org/10.4095/331878.

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Increasing global demand for lithium coupled with a need to characterize domestic resources necessitates an expanded assessment for lithium production from unconventional sources. Oilfield brines are known to host elevated lithium concentrations and represent a prime candidate for lithium extraction. The purpose of this report is to expand our knowledge of brine chemistry within the Western Canadian Sedimentary Basin with a focus on the Montney and Duvernay formations. Specifically wells that are undergoing hydrocarbon production stimulated via hydraulic fracturing (HF) are sampled with the eventual goal of assessing the suitability of extracting lithium from flowback and produced wastewater. Two water chemistry datasets are presented, the first consisting of samples derived from numerous wells within the Montney and Duvernay formations, and the second dataset includes time series samples from several wells in the Montney and Duvernay formations illustrating temporal variations in water chemistry following the onset of well re-open and fluid production after HF operations. The maximum measured lithium concentration in the Montney Fm. is 76.8 mg/L with an average of 52.9 mg/L. Maximum measured lithium concentration in the Duvernay Fm. is 78.6 mg/L with an average of 44.9 mg/L. Comparison of Montney and Duvernay sodium-chloride-bromide system with seawater evaporation trends suggests halite dissolution likely played a role in the evolution of brine chemistry. Lithium concentration in brines is positively correlated with potassium concentration and inversely correlated with pH. Water chemistry time series reveal increasing lithium concentrations over time associated with increasing proportions of formation-derived water in produced fluids. Understanding spatial and temporal variations in lithium concentrations is essential for evaluating the resource potential of oilfield brines as well as informing appropriate extraction technologies.

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Poverenov, Elena, Tara McHugh e Victor Rodov. Waste to Worth: Active antimicrobial and health-beneficial food coating from byproducts of mushroom industry. United States Department of Agriculture, janeiro de 2014. http://dx.doi.org/10.32747/2014.7600015.bard.

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Background. In this proposal we suggest developing a common solution for three seemingly unrelated acute problems: (1) improving sustainability of fast-growing mushroom industry producing worldwide millions of tons of underutilized leftovers; (2) alleviating the epidemic of vitamin D deficiency adversely affecting the public health in both countries and in other regions; (3) reducing spoilage of perishable fruit and vegetable products leading to food wastage. Based on our previous experience we propose utilizing appropriately processed mushroom byproducts as a source of two valuable bioactive materials: antimicrobial and wholesome polysaccharide chitosan and health-strengthening nutrient ergocalciferol⁽ᵛⁱᵗᵃᵐⁱⁿ ᴰ2⁾. ᴬᵈᵈⁱᵗⁱᵒⁿᵃˡ ᵇᵉⁿᵉᶠⁱᵗ ᵒᶠ ᵗʰᵉˢᵉ ᵐᵃᵗᵉʳⁱᵃˡˢ ⁱˢ ᵗʰᵉⁱʳ ᵒʳⁱᵍⁱⁿ ᶠʳᵒᵐ ⁿᵒⁿ⁻ᵃⁿⁱᵐᵃˡ ᶠᵒᵒᵈ⁻ᵍʳᵃᵈᵉ source. We proposed using chitosan and vitamin D as ingredients in active edible coatings on two model foods: highly perishable fresh-cut melon and less perishable health bars. Objectives and work program. The general aim of the project is improving storability, safety and health value of foods by developing and applying a novel active edible coating based on utilization of mushroom industry leftovers. The work plan includes the following tasks: (a) optimizing the UV-B treatment of mushroom leftover stalks to enrich them with vitamin D without compromising chitosan quality - Done; (b) developing effective extraction procedures to yield chitosan and vitamin D from the stalks - Done; (c) utilizing LbL approach to prepare fungal chitosan-based edible coatings with optimal properties - Done; (d) enrichment of the coating matrix with fungal vitamin D utilizing molecular encapsulation and nano-encapsulation approaches - Done, it was found that no encapsulation methods are needed to enrich chitosan matrix with vitamin D; (e) testing the performance of the coating for controlling spoilage of fresh cut melons - Done; (f) testing the performance of the coating for nutritional enhancement and quality preservation of heath bars - Done. Achievements. In this study numerous results were achieved. Mushroom waste, leftover stalks, was treated ʷⁱᵗʰ ᵁⱽ⁻ᴮ ˡⁱᵍʰᵗ ᵃⁿᵈ ᵗʳᵉᵃᵗᵐᵉⁿᵗ ⁱⁿᵈᵘᶜᵉˢ ᵃ ᵛᵉʳʸ ʰⁱᵍʰ ᵃᶜᶜᵘᵐᵘˡᵃᵗⁱᵒⁿ ᵒᶠ ᵛⁱᵗᵃᵐⁱⁿ ᴰ2, ᶠᵃʳ ᵉˣᶜᵉᵉᵈⁱⁿᵍ any other dietary vitamin D source. The straightforward vitamin D extraction procedure and ᵃ ˢⁱᵐᵖˡⁱᶠⁱᵉᵈ ᵃⁿᵃˡʸᵗⁱᶜᵃˡ ᵖʳᵒᵗᵒᶜᵒˡ ᶠᵒʳ ᵗⁱᵐᵉ⁻ᵉᶠᶠⁱᶜⁱᵉⁿᵗ ᵈᵉᵗᵉʳᵐⁱⁿᵃᵗⁱᵒⁿ ᵒᶠ ᵗʰᵉ ᵛⁱᵗᵃᵐⁱⁿ ᴰ2 ᶜᵒⁿᵗᵉⁿᵗ suitable for routine product quality control were developed. Concerning the fungal chitosan extraction, new freeze-thawing protocol was developed, tested on three different mushroom sources and compared to the classic protocol. The new protocol resulted in up to 2-fold increase in the obtained chitosan yield, up to 3-fold increase in its deacetylation degree, high whitening index and good antimicrobial activity. The fungal chitosan films enriched with Vitamin D were prepared and compared to the films based on animal origin chitosan demonstrating similar density, porosity and water vapor permeability. Layer-by-layer chitosan-alginate electrostatic deposition was used to coat fruit bars. The coatings helped to preserve the quality and increase the shelf-life of fruit bars, delaying degradation of ascorbic acid and antioxidant capacity loss as well as reducing bar softening. Microbiological analyses also showed a delay in yeast and fungal growth when compared with single layer coatings of fungal or animal chitosan or alginate. Edible coatings were also applied on fresh-cut melons and provided significant improvement of physiological quality (firmness, weight ˡᵒˢˢ⁾, ᵐⁱᶜʳᵒᵇⁱᵃˡ ˢᵃᶠᵉᵗʸ ⁽ᵇᵃᶜᵗᵉʳⁱᵃ, ᵐᵒˡᵈ, ʸᵉᵃˢᵗ⁾, ⁿᵒʳᵐᵃˡ ʳᵉˢᵖⁱʳᵃᵗⁱᵒⁿ ᵖʳᵒᶜᵉˢˢ ⁽Cᴼ2, ᴼ²⁾ ᵃⁿᵈ ᵈⁱᵈ not cause off-flavor (EtOH). It was also found that the performance of edible coating from fungal stalk leftovers does not concede to the chitosan coatings sourced from animal or good quality mushrooms. Implications. The proposal helped attaining triple benefit: valorization of mushroom industry byproducts; improving public health by fortification of food products with vitamin D from natural non-animal source; and reducing food wastage by using shelf- life-extending antimicrobial edible coatings. New observations with scientific impact were found. The program resulted in 5 research papers. Several effective and straightforward procedures that can be adopted by mushroom growers and food industries were developed. BARD Report - Project 4784

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