Academic literature on the topic 'NMRP'
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Journal articles on the topic "NMRP"
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Zhang, Zhang, Shigeho Takarada, and Sabee Molloi. "Quantification of coronary microvascular resistance using angiographic images for volumetric blood flow measurement: in vivo validation." American Journal of Physiology-Heart and Circulatory Physiology 300, no. 6 (June 2011): H2096—H2104. http://dx.doi.org/10.1152/ajpheart.01123.2010.
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Structural coronary microcirculation abnormalities are important prognostic determinants in clinical settings. However, an assessment of microvascular resistance (MR) requires a velocity wire. A first-pass distribution analysis technique to measure volumetric blood flow has been previously validated. The aim of this study was the in vivo validation of the MR measurement technique using first-pass distribution analysis. Twelve anesthetized swine were instrumented with a transit-time ultrasound flow probe on the proximal segment of the left anterior descending coronary artery (LAD). Microspheres were injected into the LAD to create a model of microvascular dysfunction. Adenosine (400 μg·kg−1·min−1) was used to produce maximum hyperemia. A region of interest in the LAD arterial bed was drawn to generate time-density curves using angiographic images. Volumetric blood flow measurements (Qa) were made using a time-density curve and the assumption that blood was momentarily replaced with contrast agent during the injection. Blood flow from the flow probe (Qp), coronary pressure (Pa), and right atrium pressure (Pv) were continuously recorded. Flow probe-based normalized MR (NMRp) and angiography-based normalized MR (NMRa) were calculated using Qp and Qa, respectively. In 258 measurements, Qa showed a strong correlation with the gold standard Qp (Qa = 0.90 Qp + 6.6 ml/min, r2 = 0.91, P < 0.0001). NMRa correlated linearly with NMRp (NMRa = 0.90 NMRp + 0.02 mmHg·ml−1·min−1, r2 = 0.91, P < 0.0001). Additionally, the Bland-Altman analysis showed a close agreement between NMRa and NMRp. In conclusion, a technique based on angiographic image data for quantifying NMR was validated using a swine model. This study provides a method to measure NMR without using a velocity wire, which can potentially be used to evaluate microvascular conditions during coronary arteriography.
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Gurung, DB, BR Pandey, SR Upadhyay, B. Pokhrel, and JB Kshetri. "Heterosis and yield potentialities of promising maize hybrids suitable for Terai and inner Terai environments of Nepal." Agronomy Journal of Nepal 1 (February 3, 2013): 67–73. http://dx.doi.org/10.3126/ajn.v1i0.7544.
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Heterosis has made a dramatic impact on the developing of breeding methods and high yields in many field crops during the 20th century. In general, heterosis is greatest in cross pollinated compared to self pollinated crops and thus widely exploited for hybrid cultivar development. Standard heterosis is one of the most important parameters in commercialization of maize hybrids. A new hybrid must be superior to the standard hybrids in terms of grain yield and other economic traits. We have analyzed four coordinated varietal trials of hybrids, 3 of which were conducted at NMRP, Rampur and another was tested at NMRP, Rampur and at ARS, Belachapi, Janakpur from 2006 to 2008 in order to determine the standard heterosis of the promising hybrids. The objective of this study was to evaluate hybrids under different production domains and to select superior hybrids for commercialization. Standard heterosis was calculated based on the best check hybrids and Indian commercial hybrids. The hybrids showed significant differences for grain yields and days to silking in all the trials. Standard heterosis of the tested hybrids ranged from - 39.4 to 47.8%. Most of the hybrids showed positive standard heterosis for grain yield. Hybrids namely; RML- 4/NML-2, RML-6/RML-8, NML-1/RML-8 in 2006 and RML-57/RL-174, NML-1/RML-6 and RL-197/NML-2 in 2008 had more than15% standard heterosis for grain yield evaluated at NMRP, Rampur. Hybrid between RML- 4/NML-2 had only shown positive standard heterosis in 2007 at NMRP, Rampur. RML-4/NML-2, NML-1/RL-17 and RL-111/RL-189 were superior hybrids, which had >15% standard heterosis across NMRP, Rampur and at ARS, Belachapi, Janakpur in 2008. Seed production aspect of these selected hybrids should be studied to develop a complete package of practices for F1 hybrid seed production. DOI: http://dx.doi.org/10.3126/ajn.v1i0.7544 Agronomy Journal of Nepal (Agron JN) Vol. 1: 2010 pp.67-73
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Song, Pengfei, Rong Guo, Wei Ma, Liyan Wang, Fangfang Ma, and Rongmin Wang. "Synthesis of CO2-based polycarbonate-g-polystyrene copolymers via NMRP." Chemical Communications 56, no. 66 (2020): 9493–96. http://dx.doi.org/10.1039/d0cc03665j.
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Zhang, Yan, Yufei Bian, Hui Niu, Yurong Wang, and Yang Li. "Synthesis of colorant-modified polystyrene copolymers with tailored structures for toner applications." RSC Advances 6, no. 106 (2016): 104407–15. http://dx.doi.org/10.1039/c6ra19607a.
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Charnock, Greig. "Competitiveness and Critique: The Value of a New-Materialist Research Project." Historical Materialism 16, no. 2 (2008): 117–41. http://dx.doi.org/10.1163/156920608x276305.
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AbstractFollowing Marcus Taylor's critique of Paul Cammack's 'new materialism', this paper proposes a New-Materialist Research Project (NMRP) borne out of a synthesis of the insights of both open Marxism and Cammack's project. The rationale for this lies in the conviction that a more 'applied' focus upon specific forms of contemporary class practice can aid open Marxism to move beyond general and abstract critique, thereby making an original and critical contribution to our understanding of the contemporary management of global capitalism. While the proposed NMRP refutes the problematic theorisation of relative autonomy in Cammack's original proposal, it is argued that a more rigorously theorised NMRP can extend negative critique to the current activities of international regulative agencies. By focusing on the activities of such agencies – beginning with their discursive operations – it is possible to discern how contemporary forms of ideology operate in a retroactive manner, obfuscating and distorting the contradictions being played out across the world market; and also how such agencies are seeking to exercise unprecedented levels of intervention and control in the management of individual national 'capitalisms', and under the rubric of promoting 'competitiveness'.
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POPESCU, Cristina, Mihai BAILA, Cristina DAIA, Ioana ANDONE, Daniel SERBAN, Cristian RADUCANU, Mihaela MANESCU, and Gelu ONOSE. "Neuro-muscular rehabilitation approach with favorable results in a case of a tetraplegia after a cervical ganglioneuroma – case presentation." Balneo Research Journal, Vol.11, no.4 (December 5, 2020): 530–32. http://dx.doi.org/10.12680/balneo.2020.395.
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This is the case of a 52-year-old male patient with tetraplegia and muscle respiratory failure, due to an extradural compressive cervical ganglioneuroma (C1-C2), with a history of neurological symptoms for 3 years. The tumor was completely surgically removed and the patient followed a neuro-muscular rehabilitation program (NMRP) for 4 months, consisting of rehabilitation nursing, physical and occupational therapy. At the end of NMRP the patient’s achievements were: unilateral supported walking, partial autonomous daily living functioning, the improvement of quality of life and facilitation of social and professional participation. Keywords: ganglioneuroma, spinal cord tumor, neuro-muscular rehabilitation program, non-traumatic spinal cord injury, spinal cord compression,
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Hong, Linxiang, Junpo He, Yougen Chen, and Toyoji Kakuchi. "Synthesis of ABB′ and ABC star copolymers via a combination of NMRP and ROP reactions." Polymer Chemistry 7, no. 21 (2016): 3599–607. http://dx.doi.org/10.1039/c6py00401f.
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Song, Wenguang, Jian Huang, Cheng Hang, Chenyan Liu, Xuepu Wang, and Guowei Wang. "Synthesis of thermally cleavable multisegmented polystyrene by an atom transfer nitroxide radical polymerization (ATNRP) mechanism." Polymer Chemistry 6, no. 46 (2015): 8060–70. http://dx.doi.org/10.1039/c5py01493j.
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Based on the common features of well-defined NRC reaction, ATRP and NMRP mechanisms, an atom transfer nitroxide radical polymerization (ATNRP) mechanism was presented, and further used to construct multisegmented PSm embedded with multiple alkoxyamine linkages.
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Jaymand, Mehdi. "Synthesis and Characterization of Conductive Polyaniline-Modified Polymers via Nitroxide Mediated Radical Polymerization." Polymer Korea 34, no. 6 (November 30, 2010): 553–59. http://dx.doi.org/10.7317/pk.2010.34.6.553.
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Bhandari, Ghanashyam, Shiva Kumar Jha, Yagya Prasad Giri, Hira Kaji Manandhar, Pramod Kumar Jha, Nabaraj Devkota, Praseed Thapa, and Resham Bahadur Thapa. "Performance evaluation of locally developed black light trap for maize insects monitoring in Chitwan, Nepal." Journal of Maize Research and Development 3, no. 1 (January 5, 2018): 98–107. http://dx.doi.org/10.3126/jmrd.v3i1.18926.
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Till today, the light traps in Nepal are found using with traditional type, which have not being recognized internationally. These light traps were of low efficiency for trapping insects as compared to black light trap (BLT). The black light tube (F10T8/BL) was used in newly constructed trap at National Maize Research Program (NMRP), Rampur, Chitwan, Nepal. Both traps were installed at the maize experimental field at NMRP during February to October, 2017. Data on insect numbers were recorded once in a week from dusk to down in two different days to minimize the light effects of each others. The total number of insects trapped in BLT was 2804 as compared to 868 in traditional light trap (TLT). Among the insect orders, Coleopterans were mostly trapped in BLT followed by Lepidopteron and Hemipterans. The results showed that the trapping efficiency of BLT was three fold higher than that of TLT. Therefore, black light trap was highly effective monitoring tool and its field applications are expected to be commercialized.
Dissertations / Theses on the topic "NMRP"
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Shooter, Andrew James. "Living free radical polymerisation." Thesis, University of Warwick, 1997. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.263817.
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Mougnier, Sébastien-Jun. "Copolymères semi-conducteurs à architectures variées : de l'ingénierie macromoléculaire à l'électronique organique." Thesis, Bordeaux 1, 2012. http://www.theses.fr/2012BOR14675/document.
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A une époque où les technologies nouvelles fleurissent chaque jour, un domaine particulier se détache : l’électronique organique. Par son utilité et sa facilité de mise en œuvre, l’électronique organique affiche de grandes promesses pour l’avenir. Dans le but d’améliorer le procédé de fabrication et la durée de vie de ces dispositifs, le travail de cette thèse s'est focalisé sur la synthèse de copolymères à architectures variées à base de poly(3-hexylthiophène) (P3HT). Après avoir exposé les problématiques et objectifs de la thèse dans une première partie, la synthèse de différents précurseurs P3HT est décrite. Ces matériaux représentent la base des travaux présentés dans cet ouvrage. Dans un premier temps, l'optimisation de la synthèse des copolymères à blocs rigide-flexible a été réalisée en suivant une stratégie adaptée pour une application en électronique organique. La conception de nouveaux matériaux semi-conducteurs à architectures ramifiées est traitée par la suite. Enfin, le dernier chapitre porte sur l'intégration d’un copolymère, le P3HT-b-Poly(4vinylpyridine), en cellule photovoltaïque organique en tant qu'additif de la couche active. Cette approche s’avère être particulièrement puissante, permettant notamment de diminuer le temps et le coût énergétique de la mise en œuvre de ces cellules en s’affranchissant d’une étape clé de la fabrication, le recuitAt a time when new technologies emerge every day, a specific domain stands out: the organic electronic. Through its low cost processing or even its utility, the organic electronic constitutes a very promising future.In order to improve the fabrication process and the lifetime of the devices, the work of this thesis was focused on the synthesis of copolymers with various architectures based on poly(3-hexylthiophene) (P3HT). After a first part where main issues and objectives are presented, the synthesis of different P3HT-based precursors is described in a part which could be considered as the heart of these works. Starting with appropriated precursors, the optimization of rod-coil diblock copolymer synthesis was performed following a strategy designed specifically for organic electronic application. Moreover, the precursors were used for the conception of new semi-conducting materials with a variety of architectures, such as graft and star copolymers. Finally, the last part deals with the integration of the P3HT-b-Poly(4-vinylpyridine) copolymer into organic solar cell as an additive of the active layer. This approach turns out to be powerful, especially allowing decreasing the time and the energy cost by avoiding the key step of the fabrication process of those devices, the annealing step
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Gonçalves, Maria Cecilia. "Estudo experimental da polimerização via radical livre controlada em presença de radicais nitroxido (NMRP)." [s.n.], 2006. http://repositorio.unicamp.br/jspui/handle/REPOSIP/266346.
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Orientador: Liliane Maria Ferrareso LonaDissertação (mestrado) - Universidade Estadual de Campinas. Faculdade de Engenharia Quimica
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Resumo: A polimerização via radical livre controlada mediante radicais nitróxido (NMRP) tem recebido cada vez mais atenção como uma técnica para produção de polímeros com estrutura altamente controlada. Distribuições de pesos moleculares estreitas são obtidas, com polidispersidades baixas. Neste trabalho, será estudado o processo NMRP, no qual ocorre a adição de um radical nitróxido estável, como o 2,2,6,6-tetrametil-l-piperidinoxil (TEMPO) para capturar o radical em crescimento. Embora o processo NMRP de ao polímero características controladas (polidipersidades baixas e pesos moleculares que aumentam linearmente com a conversão), ainda existe um desafio nos processos controlados, por apresentarem baixas velocidades de reação. O objetivo principal deste trabalho está focado num estudo experimental do processo NMRP visando aumentar a velocidade de reação sem perder as características principais do processo. O efeito de dois iniciadores BPO (peróxido de benzoíla) e TBEC (tert-butilperóxido-2-etilhexil carbonato) foi analisado. Observou-se que o TBEC (iniciador com constante de decomposição baixa) foi capaz de aumentar significativamente a taxa de polimerização do processo NMRP, quando comparado ao BPO, pois conversões mais altas foram obtidas, num mesmo tempo de reação, mantendo a característica controlada do sistema. O uso do TBEC apresenta uma vantagem frente ao BPO em processos controlados, não somente porque reduz o tempo de reação, mas também porque concentrações menores de iniciador e controlador foram usadas, obtendo uma taxa de reação ainda maior, o que reduz o custo operacional. Para as condições estudadas, comprovou-se experimentalmente que a taxa de reação é inversamente proporcional à concentração inicial de TEMPO, para uma mesma concentração de iniciador. A análise dos resultados através da aplicação da técnica de planejamento de experimento auxiliou numa melhor compreensão do sistema e na obtenção de condições ótimas de operação para se obter baixas polidispersidades e baixos tempos de polimerização
Abstract: NMRP process (Nitroxide Mediated Radical Polymerization) has received increasing attention as a technique for production polymers with highly controlled structures, narrow molecular weight distribution (MWD) and polydispersity index dose to 1.0. In this work 2,2,6,6-tetramethyl-l-piperidinoxyl (TEMPO) is used as the stable radical to reversibly terminate the growing polymer chain. Polymerizations were performed in ampoules, using TBEC (tert-butylperoxy-2-ethylhexyl carbonate) and BPO (benzoyl peroxide) as initiators. With the purpose of enhancing the reaction rate for NMRP process maintaining the controlled and living characteristics of the polymer synthesized (low polidispersity and molecular weights increasing linearly with conversion) an experimental study was done to evaluate the effect of two different initiators (BPO and TBEC). It was observed that TBEC (initiator with low decomposition rate) was able to enhance significant1y the polymerization rate compared to BPO, keeping the living and controlled characteristics of the system. The results show that TBEC seems to be a promising initiator that make the NMRP process more efficient, not only because it reduces the polymerization time, but also because it allows smaller amounts of controller and initiator to be used. For the operational conditions studied, experimental results with TBEC exposed that the polymerization rate in inversely proportional to the initial concentration of TEMPO, for the same amount of initiator. Using a statistical planning, it was possible to obtain a better understanding of the system and to search for operating conditions that bring low polydispersity and low reaction rates. Finally, the results are expected to have significant benefits for controlled polymerization on an industrial setting
Mestrado
Desenvolvimento de Processos Químicos
Mestre em Engenharia Química
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Fleischmann, Sven. "Alkinhaltige Blockcopolymere und ihre Modifizierung mittels 1,3-dipolarer Cycloaddition." Doctoral thesis, München Verl. Dr. Hut, 2008. http://d-nb.info/991285212/04.
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Sieczkowska, Barbara. "Functional polymer layers with protected amines." Doctoral thesis, Saechsische Landesbibliothek- Staats- und Universitaetsbibliothek Dresden, 2009. http://nbn-resolving.de/urn:nbn:de:bsz:14-ds-1244668077080-12212.
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This work refers to the area of bio-nanotechnology and concerns the selective immobilization of DNA or other bio-template on microstructured gold contacts and which then permit a coordinated cooperation of several of these nanotemplate, e.g., within a microreactor. The immobilization of such nano-objects should be realized through functional thin polymer films which provide binding groups. Thus, the main aim of this work was the development of polymeric materials for thin functional films which permit to deposit on different substrates a wide variation of functional elements or metal structures and to achieve a pattern formation using optical grid methods. In order to realize this concept it was necessary to design and develop a polymer system based on suitable photolabile units and in addition having anchoring groups which attach on specific substrates like gold. In this terpolymer concept was aimed for which consists of three components with particular functions in suitable molar ratios, which allow the tune the properties of the materials, and provide: amino photolabile protected groups for the photolithographic creation of patterned areas with free amino groups, which are available for further modifications like attachment of colloids, metallization or attachment of DNA strands; disulfide derivative anchor groups providing anchoring capacity for gold surface and spacer groups for adjusting the film quality. These multifunctional terpolymers should be synthesised by free radical polymerisation of suitable monomers. Although these techniques are successful, they are limited by their complexity, rigorous synthetic demands, as well as incompatibility with many functional termolabile and highly reactive functionalities. To overcome these difficulties a polymerisation technique based on “living” free radical polymerisation has been used in this work. A highly efficient polymer-analogous modification allows to introduce the functionalities after the polymer construction reaction. The production of suitable prepolymers [poly(styrene-r-4-propargyl-oxystyrene)] was carried out with the help of a controlled synthesis methodology “nitroxide mediate radical polymerization" followed by polymer analogous reaction using one of the most efficient click reactions, the Cu(I) catalyzed Huisgen 1,3-dipolar cycloaddition between terminal acetylenes and azides to attach further functionalities through the formation of a stable 1,4-disubstituted 1,2,3-triazol ring . The combination of nitroxide mediated radical polymerization (NMRP) and click chemistry was used to produce well-defined random copolymer. It could already be shown that also block copolymers can be prepared which give the chance to combine nanostructure formation in block copolymers with special functionality. Thus, the special properties of these functional polymers like the capability for photopatterning and anchoring onto gold substrates make them very interesting for nanotechnology applicationsDiese Arbeit bezieht sich auf das Gebiet der Bionanotechnologie und betrifft ein neuartiges Verfahren zur selektiven Immobilisierung der DNA oder anderer Biomoleküle auf mikrostrukturierten Goldkontakten, welche dann ein koordiniertes Zusammenwirken von einzelnen Nanomolekülen ermöglichen, z.B. in einem Mikroreaktor. Die Immobilisierung solcher Nanoobjekte soll durch dünne Funktionsschichten realisiert werden, die die Anbindungsgruppen liefern. Folglich war das Hauptziel dieser Arbeit die Entwicklung von Polymermaterialien für dünne Funktionsschichten, die die Aufbringung einer großen Vielzahl von Funktionselementen oder metallischen Strukturen auf verschiedenen Substraten gestatten und die Strukturierung durch den Einsatz von lithographischen Methoden ermöglichen. Um dieses Konzept zu realisieren, war es notwendig, ein Polymersystem zu gestalten und zu entwickeln, welches auf geeignete photolabile Einheiten basiert und zusätzlich Ankergruppen hat, die mit spezifischen Substraten wie Gold verbunden ist. Dieses Terpolymerkonzept wurde gezielt aus drei Komponenten mit speziellen Funktionen in entsprechenden molaren Verhältnissen gebildet, die eine Abstimmung der Materialeigenschaften ermöglicht und folgendes bereitstellt: photolabile geschützte Aminogruppen für die photolitographische Strukturerzeugung mit freien Aminogruppen, welche für weitere Modifikationen verfügbar sind wie das Anhängen von Kolloiden, die Metallisierung oder Anfügung von DNA-Strängen; disulfide Derivate für die kovalente Anbindung auf der Goldoberfläche und Spacer-Gruppe für Verbesserung der Schichtenbildung. Diese multifunktionalen Terpolymere sollen durch eine freie radikalische Polymerisation von entsprechenden Monomeren synthetisiert werden. Obwohl diese Techniken erfolgreich sind, sind sie eingeschränkt durch ihre Komplexität, den strengen synthetischen Anforderungen, sowie der Inkompatibilität mit vielen funktionalen thermolabilen und hochreaktiven Funktionalitäten. Um diese Schwierigkeiten zu überwinden wurde eine Polymerisationstechnik für diese Arbeit genutzt, die auf der „lebenden“ freien radikalischen Polymerisation basiert. Eine hoch effiziente polymeranaloge Modifizierung erlaubt die Einführung von Funktionalitäten nach der Polymeraufbaureaktion. Die Herstellung von entsprechenden Präpolymeren Poly(Styrol-r-4-Propargyl-oxystyrol) wurde mittels einer kontrollierten Synthesemethodik „Nitroxid-mediated controled radical polymerisation“ (NMRP) durchgeführt, gefolgt von der Polymeranalogreaktion, die eine der effizientesten Click-Reaktion - die Cu(I) katalysierte 1,3-dipolar Cycloaddition von terminalen Alkinen an Aziden nach Huisgen nutzt, um weiter Funktionalitäten durch die Bildung eines stabilen 1,4-disubstituierten-[1,2,3]-Triazolringes anzufügen. Die Kombination von NMRP und Click-Chemie wurde zur Herstellung eines exakt definierten Random Copolymers genutzt. Es konnte bereits gezeigt werden, dass auch Blockcopolymere geschaffen werden können, die eine Möglichkeit zur Kombination von Nanostrukturformationen in Blockcopolymeren mit speziellen Funktionaltäten bieten. Folglich sind die speziellen Eigenschaften dieser Funktionalpolymere wie die Fähigkeit zur Photostrukturierung und Verankerung auf Goldsubstraten für nanotechnologische Anwendungen sehr interessant
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Nogueira, Telma Regina. "Investigação experimental da copolimerização de estireno divinilbenzeno (DVB) via radical livre controlada por radicais nitroxido (NMRP)." [s.n.], 2008. http://repositorio.unicamp.br/jspui/handle/REPOSIP/267631.
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Orientador: Liliane Maria Ferrareso LonaDissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Engenharia Quimica
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Resumo: Polimerização via radical livre controlada, também conhecida como "pseudoliving radical polymerization" tem recebido cada vez mais atenção como uma técnica para produção de polímeros com micro estrutura altamente controlada. Em particular, distribuições de pesos moleculares estreitas são obtidas, com polidispersidade muito próxima de um. Rotas convencionais para polímeros como estes têm sido polimerizações iônicas, no entanto, elas são extremamente sensíveis a impurezas e ao tipo de solvente. Processos de polimerização via radical livre, que são muito mais versáteis e robustos a impurezas, para a produção de polímeros com estruturas controladas via processo "controlado" ou "pseudo-living", têm se tornado uma importante alternativa. Como desvantagem do processo controlado aponta-se a baixa velocidade de reação quando comparada à polimerização convencional. A maioria dos trabalhos publicados sobre polimerização controlada via radicais nitróxido é feita considerando o estudo da homopolimerização de estireno. Neste projeto de pesquisa, é investigada, em nível experimental, a co-polimerização de estireno e divinilbenzeno (DVB) via polimerização controlada por nitróxidos (NMRP) usando 2,2,6,6- tetrametil-1-piperidinoxil (TEMPO) como controlador e tert-butilperóxido-2-etilhexil carbonato (TBEC) como iniciador. O DVB funciona como gerador de ramificações na cadeia polimérica, melhorando as propriedades do estireno como resistência a solvente e ao impacto. O TBEC foi utilizado em substituição a iniciadores mais convencionais como o 2,2-azo-bis-iso-butironitrila (AIBN) e peróxido de benzoíla (BPO), com o objetivo de acelerar a velocidade de reação, tentando manter o sistema controlado. Todos os experimentos foram feitos em ampolas. Para um melhor entendimento deste sistema, muitos experimentos foram realizados a diferentes temperaturas, concentrações de divinilbenzeno, concentrações de iniciador e razões molares entre as concentrações de controlador e iniciador. A conversão do monômero foi obtida por gravimetria e o polímero foi caracterizado através de Cromatografia de Permeação em Gel (GPC). Foi demonstrado que o TBEC foi capaz de aumentar a velocidade de reação em relação ao BPO e, em algumas condições operacionais utilizadas, polidispersidades próximas da unidade foram obtidas.
Abstract: Living free radical polymerization, also known as "pseudo-living radical polymerization" has received more and more attention as a technique for the production of polymers with micro structure highly controlled (narrow molecular weights distributions and polydispersity index close to one). Conventional routes to obtain polymer like this have been ionic polymerizations, however, they are extremely sensitive to impurities and solvents. Free radical polymerizations, which are more versatile and robust to impurities, for the production of polymers with controlled structures by "controlled" or "pseudo-living" process, have become an important alternative. As a disadvantage of the controlled process can be pointed the low reaction rate when compared to the conventional process. Most of the published papers about nitroxide mediated living free radical polymerization consider the homopolymerization of styrene as case study. In this research, the co-polymerization of styrene and divinylbenzene (DVB) by living free radical polymerization (NMRP) is investigated in experimental level. The stable radical used was 2,2,6,6-tetramethyl-1-piperidinoxyl (TEMPO). The initiators used in this work were tertbutylperoxy- 2-ethylhexyl carbonate (TBEC) and benzoyl peroxide (BPO). DVB acts as a branching generator, improving the properties of the styrene as the solvent and impact resistance. TBEC was used in substitution to conventional initiators as 2, 2-Azo-bisisobutyronitrile (AIBN) and BPO, with the aim of accelerating the reaction rate, trying to keep a controlled/living system. All the experiments were performed in ampoules. To better understand this system, many experiments were performed at different temperatures, divinylbenzene concentrations, initiator concentrations and molar ratios between controller and initiator. Conversion was obtained by gravimetric method and the polymer was characterized by Gel Permeation Chromatograph (GPC). It was observed that, at certain operating conditions, the TBEC initiator was able to produce copolymers with polydispersity close to unity in a much faster velocity when compared to BPO.
Mestrado
Processos Quimicos
Mestre em Engenharia Química
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Thiessen, Wladimir. "Polymere und Nanopartikel - Verfahren für die Chemische Nanotechnologie." Doctoral thesis, Saechsische Landesbibliothek- Staats- und Universitaetsbibliothek Dresden, 2011. http://nbn-resolving.de/urn:nbn:de:bsz:14-qucosa-65374.
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In der vorliegenden Arbeit soll das weit gefächerte Thema der chemischen Nanotechnologie um neue Resultate bereichert werden. Im Einzelnen handelt es sich um neue Synthesemethoden für magnetische Nanorods (Nanoteilchen mit länglicher Form) und Nanoshells (oxidische Nanokristalle mit einer Hülle aus Edelmetall), ein Verfahren zur Modifizierung diverser Oberflächen mit heterogenen Polymerbürsten durch kontrollierte binäre radikalische Polymerisation, neuartige Copolymere zur Stabilisierung und Funktionalisierung von Nanopartikeln und Herstellung von amphiphilen Nanopartikeln durch Oberflächenbehandlung mit Niotensiden. Es sollen ferner die möglichen Anwendungen diskutiert werden. Die Abb. 1 illustriert die Zusammenhänge der bearbeiteten Thematik.
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Galhardo, Eduardo 1982. "Viabilização da polimerização mediada por nitróxidos (NMRP) em emulsão por meio da variação de parâmetros de processos." [s.n.], 2013. http://repositorio.unicamp.br/jspui/handle/REPOSIP/266601.
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Orientador: Liliane Maria Ferrareso LonaTese (doutorado) - Universidade Estadual de Campinas, Faculdade de Engenharia Química
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Resumo: A polimerização via radical livre controlada, também conhecida como "Living Free Radical Polymerization" (LFRP) tem recebido cada vez mais atenção como uma técnica para produção de polímeros com cadeias monodispersas. Em particular, distribuições de massas moleculares estreitas são obtidas, com polidispersidade muito próxima de um. Rotas convencionais para polimerizações como esta têm sido as iônicas, no entanto, elas são extremamente sensíveis a impurezas e tipo de solvente. Desta forma, processos de polimerização via radical livre, que são muito mais versáteis e robustos a impurezas, para a produção de polímeros com estruturas controladas via processo "controlado", tem se tornado uma importante alternativa. Neste projeto de pesquisa, foi feito um estudo em nível experimental para investigar a polimerização controlada mediada por nitróxidos (NMRP, do inglês, Nitroxide Mediate Radical Polymerization), utilizando-se a polimerização em emulsão. Esse tipo de polimerização apresenta alta versatilidade industrial e também um ganho ambiental, já que um solvente orgânico é, nesse caso, substituído por água. Um dos desafios enfrentados em processar a polimerização NMRP em emulsão foi à manutenção da água em seu estado líquido, já que o processo NMRP, utilizando-se TEMPO (2, 2, 6,6-tetrametil-1-piperidinoxil) como controlador, somente se dá a uma temperatura maior que 100ºC, o que exigiu a pressurização do sistema. As quantidades de surfactante (SDS) foram alteradas de forma sistemática: 5,00 7,50 e 10,00 g. Percebeu-se que, usando 5,00g de SDS, menores polidispersidades e massas moleculares foram alcançadas, o que prova uma relação entre esses parâmetros e o número de partículas nucleadas. A relação monômero/água (v/v) também foi alterada, a saber: 0,33, 0,55, 0,70 e 0,75. Percebeu-se que a relação 0,75 forneceu as menores polidispersidades e as maiores massas moleculares. Um estudo teórico realizado com o Software Gaussian 3.0 mostrou os valores da entalpia para a espécie alquociamina dormente e para a reação global
Abstract: Controlled radicalar polymerization, known also by Living Free Radical Polymerization, has received every time more attention as being a technique for production of polymer with highly controlled microstructure. Particularly, narrow molecular weight distributions are reached, with polydispersity very close to one. Conventional routes for polymerizations like this has been the ionic, however, it is extremely sensitive to impurities and kind of solvent. This way, processes of polymerization via free radical, which are much more versatile and robust to impurities for the polymer production with controlled structures via "controlled process", has been an important alternative. In this work Nitroxide Mediated Radical Polymerization (NMRP) using TEMPO (2,2,6,6-tetrametyl-1-piperidinoxyl) as controller and emulsion polymerization was investigated. Conventional emulsion polymerization presents high industrial versatility, due to range of monomers that can be applied, and also an environmentally advantage, because an organic solvent is replaced by water. One of the challenges faced was keeping the water in liquid physical state, because the maximum efficiency of the process occurs at a temperature higher than 115ºC, what demanded the pressurization of the system. The quantities of surfactant (SDS) were systematically changed: 5.00, 7.50 and 10.00 g, respectively. It was perceived that using 5.00 g of SDS, lower values of polydispersity and molecular weight were obtained, what ensures a relation between such parameters and the number of nucleated particles. The relation monomer/water (v/v) was also changed, namely: 0.33, 0.55, 0.70 and 0.75. It was noticed that the relation 0.75 provided the lowest polydispersities and the highest molecular weights. The theoretical study performed with the Software Gaussian 3.0 showed the enthalpy values for the dormant alkoxyamine specie and for the global reaction
Doutorado
Desenvolvimento de Processos Químicos
Doutor em Engenharia Química
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Simms, Ryan W. "Living/controlled Polymerization Conducted in Aqueous Based Systems." Thesis, Kingston, Ont. : [s.n.], 2007. http://hdl.handle.net/1974/700.
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Dias, Rafael Silva. "Investigação experimental e computacional da polimerização via radical livre controlada em presença de radicais nitroxido (NMRP) utilizando-se iniciadores difuncionais." [s.n.], 2008. http://repositorio.unicamp.br/jspui/handle/REPOSIP/266460.
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Orientador: Liliane Maria Ferrareso LonaTese (doutorado) - Universidade Estadual de Campinas, Faculdade de Engenharia Quimica
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Resumo: Polimerização via radical livre controlada, ou Living Free Radical Polymerization (LFRP) tem recebido cada vez mais atenção como uma técnica para produção de polímeros com micro estrutura altamente controlada. Em particular, distribuições de pesos moleculares estreitas são obtidas, com polidispersidade próxima de um. Rotas usuais para obtenção de polímeros como estes têm sido polimerizações iônicas, mas elas são extremamente sensíveis a impurezas. Dentre os processos controlados, a polimerização mediada por nitróxidos (Nitroxide-Mediated Radical Polymerization-NMRP) permite a introdução de funcionalidades químicas na cadeia polimérica e apresenta como vantagens a possibilidade de polimerizações em meio aquoso, síntese de materiais híbridos, copolímeros, além de ser a rota química com menor impacto no meio-ambiente. Contudo, um dos desafios a ser enfrentado na LFRP, inclusive na NMRP, é o aumento da velocidade de reação, uma vez que as polimerizações controladas são muito mais lentas em função da existência de uma etapa de equilíbrio intrínseca. Na busca de maiores produtividades, utilizam-se temperaturas de operação ou concentração de iniciadores monofuncionais elevadas que, por conseqüência, geram polímeros com pesos moleculares mais baixos. Nos processos de polimerização convencional, o uso de iniciadores difuncionais permite o aumento da produtividade sem alterações ou mesmo com um aumento dos pesos moleculares. Sendo assim, nesta tese, foi feito um estudo experimental (polimerização em ampolas) e de simulação (desenvolvimento de modelos determinísticos e empíricos) para investigar a NMRP, no sentido de tentar reduzir o tempo gasto na polimerização, através do uso de iniciadores difuncionais. Particularmente, foram avaliadas as massas moleculares e a polidispersidade do poliestireno sintetizado usando o TEMPO (2,2,6,6, tetrametil-1-piperidinoxil) como controlador através de uma comparação com iniciadores monofuncionais (BPO e TBEC). Através de um planejamento de experimentos, determinou-se a influência da concentração do iniciador difuncional L531, da razão controlador/iniciador, e da temperatura na conversão, nos pesos moleculares e na polidispersidade e chegou-se a um modelo empírico. Foi proposto um mecanismo de reação com a derivação de equações de balanço de massa e de momentos para um reator batelada. Fez-se um bom ajuste do modelo com a estimativa de alguns parâmetros. Finalmente, desenvolveu-se uma análise de sensibilidade (dinâmica) dos parâmetros do modelo. Ambos os resultados experimentais e de simulação mostraram que foi possível obter um aumento na conversão aliado a um incremento nas massas moleculares ao se usar o iniciador difuncional L531 em relação ao monofuncionais, sendo mantido o processo controlado. Esta abordagem é inédita, pois não foi encontrado na literatura aberta nenhum tipo de polimerização radicalar controlada por nitróxidos que faça uso de iniciadores com funcionalidade superior a um.
Abstract: Controlled/Living Free Radical Polymerization (LFRP) is one of the most important techniques for production of polymeric materials with good control of the microstructure (e.g., narrow molecular weight distributions). Such properties can also be achieved via ionic polymerizations, but being a free radical polymerization process, LFRP is much less sensitive to impurities and solvents. The Nitroxide-Mediated Radical Polymerization (NMRP), as well as other LFRP processes, provides end functional polymers, and recently it has shown advantages related to polymerization in aqueous media, synthesis of hybrid materials, block copolymers, and environmental issues. However, one challenge that still must be overcome in LFRP, as well as in NMRP process, is to increase slow polymerization rates experienced due to the establishment of an intrinsic equilibrium. In order to achieve higher productivities, higher reaction temperatures or higher (monofunctional) initiator concentrations are usually used, but as a result, polymers with lower molecular weight are produced. It is well known that the use of di-functional initiators provides an enhancement of the reaction rate of conventional free radical polymerization with either no change or even an increase in molecular weight averages. Therefore, in this thesis, it was taken an experimental (polymerization in ampoules) and computational (deterministic and empirical methods) investigation of the effect of di-functional initiators on nitroxide-mediated radical polymerization with the purpose of enhancing the reaction rate. Particularly, the molecular weight development (number average molecular weight and polydispersity) of polystyrene synthesized by using TEMPO (2,2,6,6-tetramethyl-1-piperidinoxyl) as controller was evaluated by making a comparison with polymerizations using mono-functional initiators (BPO and TBEC). From the use of a design of experiments, the influence of the L531 initiator concentration, the TEMPO/initiator ratio, and the temperature on the reaction rate, molecular weights and polidispersity were determined, and an empirical model was generated. A kinetic mechanism has been proposed, from which mass balance and moment equations were derived for a batch reactor. The model was well adjusted to the experimental data with the estimation of some parameters. Lastly, a dynamic sensitivity analysis of the parameters was developed. It was shown both in experimental and simulation results that in the case of the bi-functional initiator L531, the reaction rate and molecular weights were increased when comparing to the performance of the mono-functional initiators keeping the livingness of the system. To the best of our knowledge, this is the first report of TEMPO-mediated polymerization of styrene using difunctional initiators.
Doutorado
Desenvolvimento de Processos Químicos
Doutor em Engenharia Química
Books on the topic "NMRP"
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Kimmich, Rainer. NMR. Berlin, Heidelberg: Springer Berlin Heidelberg, 1997. http://dx.doi.org/10.1007/978-3-642-60582-6.
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author, Haber-Pohlmeier Sabina 1962, and Zia Wasif author, eds. Compact NMR. Berlin: Walter de Gruyter GmbH & Co. KG, 2014.
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Mason, Joan, ed. Multinuclear NMR. Boston, MA: Springer US, 1987. http://dx.doi.org/10.1007/978-1-4613-1783-8.
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Ghose, Ranajeet, ed. Protein NMR. New York, NY: Springer New York, 2018. http://dx.doi.org/10.1007/978-1-4939-7386-6.
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Berliner, Lawrence, ed. Protein NMR. Boston, MA: Springer US, 2015. http://dx.doi.org/10.1007/978-1-4899-7621-5.
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Blümich, Bernhard. Essential NMR. Cham: Springer International Publishing, 2019. http://dx.doi.org/10.1007/978-3-030-10704-8.
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Iwashita, Takashi. NMR rittai kagaku: Tokuron = NMR stereo chemistry. Tōkyō: Kōdansha, 2012.
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Silva Elipe, Maria Victoria. LC-NMR and Other Hyphenated NMR Techniques. Hoboken, NJ, USA: John Wiley & Sons, Inc., 2011. http://dx.doi.org/10.1002/9781118135396.
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Akitt, J. W. NMR and chemistry: Anintroduction to modern NMR spectroscopy. 3rd ed. London: Chapman & Hall, 1992.
Find full textBook chapters on the topic "NMRP"
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Kimmich, Rainer. "Introductory Remarks." In NMR, 3–6. Berlin, Heidelberg: Springer Berlin Heidelberg, 1997. http://dx.doi.org/10.1007/978-3-642-60582-6_1.
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Kimmich, Rainer. "Spin-Relaxation Functions." In NMR, 90–96. Berlin, Heidelberg: Springer Berlin Heidelberg, 1997. http://dx.doi.org/10.1007/978-3-642-60582-6_10.
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Kimmich, Rainer. "Perturbation Theory of Spin Relaxation." In NMR, 97–101. Berlin, Heidelberg: Springer Berlin Heidelberg, 1997. http://dx.doi.org/10.1007/978-3-642-60582-6_11.
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Kimmich, Rainer. "Spin-Lattice Relaxation." In NMR, 102–15. Berlin, Heidelberg: Springer Berlin Heidelberg, 1997. http://dx.doi.org/10.1007/978-3-642-60582-6_12.
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Kimmich, Rainer. "Transverse Relaxation." In NMR, 116–24. Berlin, Heidelberg: Springer Berlin Heidelberg, 1997. http://dx.doi.org/10.1007/978-3-642-60582-6_13.
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Kimmich, Rainer. "Examples of Autocorrelation Functions." In NMR, 125–37. Berlin, Heidelberg: Springer Berlin Heidelberg, 1997. http://dx.doi.org/10.1007/978-3-642-60582-6_14.
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Kimmich, Rainer. "Field-Cycling NMR Relaxometry." In NMR, 138–48. Berlin, Heidelberg: Springer Berlin Heidelberg, 1997. http://dx.doi.org/10.1007/978-3-642-60582-6_15.
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Kimmich, Rainer. "Field-Cycling Relaxometry in Biosystems." In NMR, 149–58. Berlin, Heidelberg: Springer Berlin Heidelberg, 1997. http://dx.doi.org/10.1007/978-3-642-60582-6_16.
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Kimmich, Rainer. "The Dipolar-Correlation Effect." In NMR, 159–74. Berlin, Heidelberg: Springer Berlin Heidelberg, 1997. http://dx.doi.org/10.1007/978-3-642-60582-6_17.
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Kimmich, Rainer. "Survey of NMR Diffusometry." In NMR, 175–78. Berlin, Heidelberg: Springer Berlin Heidelberg, 1997. http://dx.doi.org/10.1007/978-3-642-60582-6_18.
Full textConference papers on the topic "NMRP"
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Gomes, Matheus G. R., Hélio F. dos Santos, and Diego F. S. Paschoal. "Predicting Co-59 NMR Chemical Shit using the NMR-DKH Basis Sets." In VIII Simpósio de Estrutura Eletrônica e Dinâmica Molecular. Universidade de Brasília, 2020. http://dx.doi.org/10.21826/viiiseedmol2020179.
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The cobalt-59 nucleus is an NMR active nucleus with the nuclear spin I = 7/2 and has a natural abundance of 100 %. It is an important nucleus because it has ease of detectable NMR signals both liquid and solid-state. The Co-59 NMR chemical shift range is one of the largest known in NMR spectroscopy, spanning some 18,000 ppm or more. However, Co-59 NMR is an extremely sensitive technique to external factors such as pressure, temperature, and others. Therefore, predicting Co-59 NMR chemical shift might be useful to assist experimentalists in the structural characterization. In the present study, we propose a new NMR-DKH basis set for Co atom to predict NMR chemical shift in Co complexes. Besides, we proposed a computational protocol (Functional DFT/Co basis set/Ligands basis set) for the prediction of the structure and, later, for the prediction of the Co-59 NMR chemical shift using 6 Co complexes as model systems. The results show that the computational protocol (NMR/structure) GIAO-B3LYP/NMR-DKH/IEF-PCM(UFF)//CAM-B3LYP/LANL2DZ/jorge-DZP/IEF-PCM(UFF) presents a mean relative deviation (DRM) of 1.48% for the structure, a mean absolute deviation (MAD) of 101 ppm and a DRM of 1.2% for the Co-59 chemical shift. Finally, the protocol was corrected by a linear regression model giving a MAD and MRD of 57 ppm and 0.7%, respectively.
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Morawitz, Falk. "Multilayered Narration in Electroacoustic Music Composition Using Nuclear Magnetic Resonance Data Sonification and Acousmatic Storytelling." In ICAD 2019: The 25th International Conference on Auditory Display. Newcastle upon Tyne, United Kingdom: Department of Computer and Information Sciences, Northumbria University, 2019. http://dx.doi.org/10.21785/icad2019.052.
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Nuclear magnetic resonance (NMR) spectroscopy is an analytical tool to determine the structure of chemical compounds. Unlike other spectroscopic methods, signals recorded using NMR spectrometers are frequently in a range of zero to 20000 Hz, making direct playback possible. As each type of molecule has, based on its structural features, distinct and predictable features in its NMR spectra, NMR data sonification can be used to create auditory ‘fingerprints’ of molecules. This paper describes the methodology of NMR data sonification of the nuclei nitrogen, phosphorous, and oxygen and analyses the sonification products of DNA and protein NMR data. The paper introduces On the Extinction of a Species, an acousmatic music composition combining NMR data sonification and voice narration. Ideas developed in electroacoustic composition, such as acousmatic storytelling and sound-based narration are presented and investigated for their use in sonification-based creative works.
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Paschoal, Diego F. S., and Joyce H. C. e. Silva. "Relativistic prediction of Pt-195 NMR chemical shift using the NMR- DKH basis sets." In VIII Simpósio de Estrutura Eletrônica e Dinâmica Molecular. Universidade de Brasília, 2020. http://dx.doi.org/10.21826/viiiseedmol2020184.
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Nuclear magnetic resonance (NMR) spectroscopy has played an important role in the discovery and design of new drugs with antitumor potential and the Pt-195 NMR has a fundamental role since the Pt-195 nucleus is very sensitive to the nature of the ligands in the coordination sphere and the oxidation state of the metal. The theoretical prediction of the Pt-195 NMR chemical shift is an extremely difficult task in which several factors must be taken into accounts, such as basis sets, electronic correlation, solvent, and relativistic effects. In an earlier study, Paschoal et al. developed the NMR-DKH basis sets and a nonrelativistic protocol for predicting the Pt-195 NMR chemical shift. The authors studied a set of 258 Pt(II) complexes and obtained a mean absolute deviation (MAD) of 168 ppm and a mean relative deviation (MRD) of 5%. However, relativistic calculations with the NMR-DKH basis sets have not been performed. Thus, the present work aims to apply the NMR-DKH in predicting the Pt-195 NMR chemical shift including the relativistic effects. The cisplatin was used as a model and its geometry was optimized and characterized as a minimum point on the potential energy surface at the B3LYP/LANL2DZ/def2-SVP/COSMO level. The Pt-195 NMR chemical shift was calculated at the DFT-Functional-DKFull/NMR-DKH/COSMO, where the functionals BP86, PBE, BLYP, PBE0, and B3LYP were tested. All calculations were carried out in NWCHEM 7.0.0 program. From the calculated results, it can be observed that the pure GGA functionals showing a better performance when compared to the hybrid functional. The best result was obtained at the BLYP-DKFull/NMR-DKH/COSMO level, where a DAM and DRM of only 34 ppm and 1.6% was found.
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Shao, Wei, Songhua Chen, Gabor Hursan, and Shouxiang Ma. "Temperature Dependence of NMR Relaxation Time in Carbonate Reservoirs." In SPE Annual Technical Conference and Exhibition. SPE, 2021. http://dx.doi.org/10.2118/206184-ms.
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Abstract NMR-based carbonate interpretation models are commonly calibrated using laboratory ambient core NMR measurements. For applying the core calibrated models to downhole NMR logging interpretation, the difference between the NMR responses measured at ambient and reservoir conditions needs to be evaluated. The temperature dependence of NMR relaxation time in high-quality carbonate reservoirs was investigated, and NMR temperature dependence models were determined using data analytic methods (Hursan et al, 2019). This paper focuses on temperature dependence of NMR relaxation time in low-quality carbonate formations. For more than 95% of the samples investigated, NMR relaxation time shows a positive correlation with temperature. The correlation is similar to that observed in high-quality carbonate rocks but slightly less significant. Temperature dependent correlations for predicting T2GM from a measured temperature to any other temperature are derived from high- and low-quality carbonate rocks independently first, then a unified T2GM correlation is derived including both the high- and low-quality carbonate reservoirs. Predicting T2 distribution from one temperature to other temperatures is achieved using dimension reduction approach involving principal component analysis (PCA) technique. It is found that the T2 distributions at any given temperature for both the high- and low-quality carbonate reservoirs can be predicted robustly from the T2 distributions at the ambient temperature by representing the T2 distributions with principal components (PCs) at the ambient temperature then using these PCs to predict the PCs at a different temperature. The optimal number of PC components depends on the multimodality of the T2 distribution. This work extends the validity range of a data analytic method that quantifies the temperature dependence of carbonate NMR properties. The new NMR temperature model enables the integration of NMR laboratory studies and dowhole measurements for advanced petrophysical analyses in a wide range of carbonate reservoirs.
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Xie, Z. Harry, Thomas Gentzis, and Humberto Carvajal-Ortiz. "MEASURING KEROGEN, SOLID ORGANICS, AND OIL PRODUCTION POTENTIALS OF UNCONVENTIONAL SOURCE ROCKS USING SOLID TYPE 20-MHZ NMR TECHNIQUES." In 2021 SPWLA 62nd Annual Logging Symposium Online. Society of Petrophysicists and Well Log Analysts, 2021. http://dx.doi.org/10.30632/spwla-2021-0094.
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It is well known that the NMR relaxation time T2 is proportional to the molecular mobility of water or hydrocarbons in rocks. In unconventional tight rocks, water and hydrocarbons are trapped in small pores of nanometer sizes, and their molecular mobility is severely restricted, causing the NMR T2 to be much shorter than that of conventional cases where pore sizes are in micrometer ranges. There are demands for advanced NMR techniques to study those solid-like bound hydrocarbons. In the meantime, it is of great interest for petrophysicists and geochemists to understand kerogen models in order to determine thermal maturity and hydrocarbon potential of organic-rich source rocks, and always attractive to have practical techniques that are nondestructive and less time consuming. In this study, a series of NMR 1D and 2D experiments have been performed on various types of source rocks with emphasis on short NMR T2 components, from sub-milliseconds down to a few microseconds, which are associated with kerogen, heavy hydrocarbons, and small hydrocarbon molecules bound in nanopores. The results show that the NMR CPMG pulse sequence used for the T2 data acquisition is (1) not capable of detecting and measuring the very rigid solid component of the T2 shorter than 30 microseconds, which is thought from kerogen, and (2) uncertain for the NMR components with T2 between 30 microseconds and 0.1 ms, which is dependent on the inter-echo spacing time (TE). Instead, the solid echo-pulse sequence was used to acquire the early time NMR signals that represent rigid solid matters, such as kerogen, in rock samples that have short relaxation times of less than 20 microseconds. The NMR solid echo signals were fitted into a composition of a Gaussian plus exponential functions to better describe NMR responses of source rocks with the shortest relaxation time of a few microseconds. The Gaussian component in the NMR signal is the measure of rigid solids associated with kerogen in the source rock. Model rock samples of thermally immature outcrops of the Upper Jurassic Kimmeridge Clay Formation in the UK and the Green River Shale Formation in the USA were used for comparison studies between the low field solid NMR techniques and geochemical analytical methods. The thermal maturities of the samples were artificially altered through the hydrous pyrolysis method at selected temperatures. The comparison results show that the amplitude of the Gaussian component measurement by NMR strongly correlated with the S2 of pyrolysis. The NMR relaxation times of the solid portion are directly proportional to the thermal maturity determined by organic petrography. This study concludes that the nondestructive solid NMR method provides an alternative and rapid way to study solid organic matters. The combined techniques enable us to further study kerogen models and hydrocarbon-generating potentials in organic-rich source rocks.
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Sun, Nan, Tae-Jong Yoon, Hakho Lee, William Andress, Vasiliki Demas, Pablo Prado, Ralph Weissleder, and Donhee Ham. "Palm NMR and one-chip NMR." In 2010 IEEE International Solid- State Circuits Conference - (ISSCC). IEEE, 2010. http://dx.doi.org/10.1109/isscc.2010.5433836.
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Abouzaid, Ahmed, Holger Thern, Mohamed Said, Mohammad ElSaqqa, Mohamed Elbastawesy, and Sherin Ghozlan. "Nuclear Magnetic Resonance Logging While Drilling in Complex Lithology – Solution for a Glauconitic Sandstone Reservoir." In SPE/AAPG Africa Energy and Technology Conference. SPE, 2016. http://dx.doi.org/10.2118/afrc-2579089-ms.
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ABSTRACT The evaluation of logging data in shaly sand reservoirs can be a challenging task, particularly in the presence of accessory minerals such as glauconite. Accessory minerals affect the measurements of conventional logging tools, thus, introducing large uncertainties for estimated petrophysical properties and reservoir characterization. The application of traditional Gamma Ray and Density-Neutron crossover methods can become unreliable even for the simple objective of differentiating reservoir from non-reservoir zones. This was the situation for many years in the glauconite-rich Upper Bahariya formation, Western Desert, Egypt. Formation evaluation was challenging and the results often questionable. Adding Nuclear Magnetic Resonance (NMR) Logging While Drilling (LWD) data in three wells changed the situation radically. The NMR data unambiguously indicate pay zones and simplify the interpretation for accurate porosity and fluid saturation dramatically. Key to success is NMR total porosity being unaffected by the presence of accessory minerals. NMR moveable fluid directly points to the pay zones in the reservoir, while clay-bound and capillary-bound water volumes reflect variations in rock quality and lithology. Although the NMR total porosity is lithology independent, the presence of glauconite affects the NMR T2 distribution by shifting the water T2 response to shorter T2 times. This requires an adjustment of the T2 cutoff position for separating bound water from movable hydrocarbons. A varying T2 cutoff was computed by comparing NMR bound water to resistivity-based water saturation. The calibrated T2 cutoff exhibits an increase with depth indicating a decreasing amount of glauconite with depth throughout the Upper Bahariya formation. Based on these volumetrics, an improved NMR permeability log was calculated, now accurately delineating variations in rock quality throughout the different pay zones. In addition, viscosity was estimated from the oil NMR signal. The estimated values match the expected values very well and illustrate the potential of NMR to indicate viscosity variations. Many of these results are available today already in real-time by transmitting NMR T2 distributions to surface while drilling. Besides the application for formation evaluation, the data can be used to initiate optimized side-tracking and completion decisions directly after finishing the drilling operations.
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Silva, Glayson Brendown Santos, Romero Coelho Alves, and Valdecir Becker. "Performance de Música em Rede: Colaboração e prática musical à distância." In XXIV Simpósio Brasileiro de Sistemas Multimídia e Web. Sociedade Brasileira de Computação - SBC, 2018. http://dx.doi.org/10.5753/webmedia.2018.4592.
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This theoretical and experimental work provides an introductory view about the universe of network music performance (NMP). Through collaboration between musicians and researchers from the Universidade Federal da Paraíba and the Universidade Federal de Campina Grande, we performed an NMP experiment and from it we verified and analyzed the advantages, disadvantages and artistic and creative possibilities inherent in the use of the NMP ReaNINJAM tool.
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Butterworth, Jeffrey A., Lucy Y. Pao, and Daniel Y. Abramovitch. "Fitting Discrete-Time Models to Frequency Responses for Systems With Transport Delay." In ASME 2011 International Mechanical Engineering Congress and Exposition. ASMEDC, 2011. http://dx.doi.org/10.1115/imece2011-63580.
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Fitting discrete-time models to frequency-response functions without addressing existing transport delay can yield higher-order models including additional non-physical nonminimum-phase (NMP) zeros beyond those that may appear as a result of sampling. These NMP zeros can be attributed to a discrete-time representation of a Pade´ approximation to account for the transport delay [1, 2]. Here, we explore this idea in greater detail and this discussion motivates the main contribution of this paper, the presentation of a procedure for fitting a discrete-time model to experimentally measured frequency response data. The appearance of NMP zeros in a system model can complicate controller design and limits the desired closed-loop performance. This discrete-time model-fitting procedure presents a technique that will help yield a model that reflects the measured frequency-response functions accurately, while minimizing the presence of non-physical NMP zeros. The key benefit being that, with respect to previous model fits, it may be possible to eliminate all NMP zeros in the discrete-time model. In the case of model-inverse-based control design, this will allow the stable inversion of the model without the use of approximation methods to account for NMP zeros.
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Hursan, Gabor, Wei Shao, Ron Balliet, and Yasir Farooq. "Eliminating Diffusion Effects from NMR Logging Data for Enhanced Carbonate Pore Typing." In SPE Annual Technical Conference and Exhibition. SPE, 2021. http://dx.doi.org/10.2118/206233-ms.
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Abstract Transverse relaxation (T2) times measured by multi-frequency, multi-gradient nuclear magnetic resonance (NMR) logging tools are affected by diffusion-induced enhanced relaxation which reduces the sensitivity to pore size in slow-relaxing formations such as macroporous carbonates and complicates the integration with zero-gradient core NMR data. We propose a solution for eliminating the diffusion-related uncertainties using intrinsic T2 distributions, obtained by a new inversion-forward modeling-inversion (IFMI) method, for carbonate pore typing applications. The NMR logs presented in this paper are based on data measured at five frequencies where the static magnetic field gradient varies from 26 to 55 G/cm. The high-quality echo signals are processed using a three-step IFMI differential signal analysis approach which nullifies diffusion effects due to the tool gradient and the potentially present internal gradient caused by paramagnetic minerals in the formation. The resulting diffusion-free intrinsic T2 distribution accentuates fine pore size variations and allows better discernment of micro-, meso-, and macropore systems of complex carbonate reservoirs. Multi-frequency NMR data, acquired in multiple wells, were processed and analyzed in several ways. First, apparent T2 distributions were obtained separately for individual frequencies. Discrepancies between the results of different frequencies clearly indicated that in macro- and mesoporous carbonates the diffusion effect is significant even with TE=0.3ms. This leads a peak broadening observed in the apparent T2 spectrum from conventional NMR processing, where echo trains from different frequencies are averaged in time-domain prior to the inversion. With the IFMI processing, individual-frequency echo trains are first pre-processed using a 2D NMR inversion whose results are used to forward model a diffusion-free echo train without prior assumptions on reservoir fluid diffusivity D. A second inversion, applied on the diffusion-free echo train, yields the intrinsic T2 distribution. The intrinsic T2 distribution has a noticeably higher spectral resolution in carbonate formations where diffusion effect is significant. The intrinsic T2 logs are expected to be more consistent with other gradient-free NMR measurements such as core NMR or LWD NMR data sets.
Reports on the topic "NMRP"
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Czech, Joseph J., and Kenneth J. Plotkin. NMAP 7.0 User's Manual. Fort Belvoir, VA: Defense Technical Information Center, November 1998. http://dx.doi.org/10.21236/ada406645.
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Zilm, K. W. Two dimensional NMR and NMR relaxation studies of coal structure. Office of Scientific and Technical Information (OSTI), May 1992. http://dx.doi.org/10.2172/5062669.
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Zilm, K. W. Two dimensional NMR and NMR relaxation studies of coal structure. Office of Scientific and Technical Information (OSTI), November 1992. http://dx.doi.org/10.2172/6878918.
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Raftery, M. Daniel. Optical pumping and xenon NMR. Office of Scientific and Technical Information (OSTI), November 1991. http://dx.doi.org/10.2172/10138720.
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Petersen, Ane Kofod Petersen. Effekten af budgetnedskæringer i NMR. Nordic Council of Ministers, June 2016. http://dx.doi.org/10.6027/na2016-909.
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Yamamoto, Yoshihisa. Solid-State NMR Quantum Computer. Fort Belvoir, VA: Defense Technical Information Center, September 2005. http://dx.doi.org/10.21236/ada442582.
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Cho, Herman M., and Richard T. Kouzes. PVT Degradation Studies: NMR Analysis. Office of Scientific and Technical Information (OSTI), June 2017. http://dx.doi.org/10.2172/1411933.
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Friedman, Gennady, and Alan Feinerman. Summary of Miniature NMR Development. Office of Scientific and Technical Information (OSTI), December 2000. http://dx.doi.org/10.2172/829904.
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Raftery, M. D. Optical pumping and xenon NMR. Office of Scientific and Technical Information (OSTI), November 1991. http://dx.doi.org/10.2172/6653527.
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T. STEPHENS and A. LABOURIAU. SOLID-STATE NMR - PROGRESS REPORT. Office of Scientific and Technical Information (OSTI), August 2000. http://dx.doi.org/10.2172/768913.
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