Academic literature on the topic 'Growth from solution'
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Journal articles on the topic "Growth from solution"
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Miyake, Hideto, Hiroyuki Ohtake, and Koichi Sugiyama. "Solution growth of CuInSe2 from CuSe solutions." Journal of Crystal Growth 156, no. 4 (1995): 404–9. http://dx.doi.org/10.1016/0022-0248(95)00280-4.
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Iurchenko, A. N. "Growth peculiarities of doped lithium dihydrogen phosphate single crystals from nonstoichiometric solution." Functional materials 24, no. 2 (2017): 005–236. http://dx.doi.org/10.15407/fm24.02.226.
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Saito, Yukio. "Physics of Crystal Growth IV: Crystal Growth from the Solution." Materia Japan 49, no. 10 (2010): 471–76. http://dx.doi.org/10.2320/materia.49.471.
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Burlakov, Victor M., and Alain Goriely. "Ligand-Assisted Growth of Nanowires from Solution." Applied Sciences 11, no. 16 (2021): 7641. http://dx.doi.org/10.3390/app11167641.
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We consider the development of ligand-assisted growth processes for generating shape-anisotropic nanomaterials. Using statistical mechanics, we analyze the conditions under which ligand-assisted growth of shape-anisotropic crystalline nanomaterials from solution can take place. Depending on ligand-facet interaction energy and crystal facet area, molecular ligands can form compact layers on some facets leaving other facets free. The growth process is then restricted to free facets and may result in significant anisotropy in crystal shape. Our study uncovers the conditions for ligand-assisted growth of nanoplatelets and nanowires from isotropic or anisotropic seed nanocrystals of cuboid shape. We show that in contrast to nanoplatelets, ligand-assisted growth of nanowires requires certain anisotropy in the ligand-facet interaction energy.
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Piana, Stefano, Manijeh Reyhani, and Julian D. Gale. "Simulating micrometre-scale crystal growth from solution." Nature 438, no. 7064 (2005): 70–73. http://dx.doi.org/10.1038/nature04173.
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Tarasevich, Yu Yu. "Computer simulation of crystal growth from solution." Technical Physics 46, no. 5 (2001): 627–29. http://dx.doi.org/10.1134/1.1372959.
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Dougherty, A., and J. P. Gollub. "Steady-state dendritic growth ofNH4Br from solution." Physical Review A 38, no. 6 (1988): 3043–53. http://dx.doi.org/10.1103/physreva.38.3043.
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Kurakevych, Oleksandr O. "Restricted growth of solid phase from solution." Materials Chemistry and Physics 105, no. 2-3 (2007): 401–7. http://dx.doi.org/10.1016/j.matchemphys.2007.05.006.
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Tracy, S. L., C. J. P. François, and H. M. Jennings. "The growth of calcite spherulites from solution." Journal of Crystal Growth 193, no. 3 (1998): 374–81. http://dx.doi.org/10.1016/s0022-0248(98)00520-x.
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Tracy, S. L., D. A. Williams, and H. M. Jennings. "The growth of calcite spherulites from solution." Journal of Crystal Growth 193, no. 3 (1998): 382–88. http://dx.doi.org/10.1016/s0022-0248(98)00521-1.
Full textDissertations / Theses on the topic "Growth from solution"
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Nerowski, Alexander. "Electrochemical Metal Nanowire Growth From Solution." Doctoral thesis, Saechsische Landesbibliothek- Staats- und Universitaetsbibliothek Dresden, 2013. http://nbn-resolving.de/urn:nbn:de:bsz:14-qucosa-118937.
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The aim of this work is to make electrochemical metal nanowire growth a competitive method, being up to par with more standardized procedures, like e.g. lithography. This includes on the one hand the production of nanowires as reliable and reproducible parts, potentially suited for nanoelectronic circuit design. Therefore, this work presents a systematic investigation of the causes of nanowire branching, the necessary conditions to achieve straight growth and the parameters affecting the diameter of the wires. The growth of ultrathin (down to 15 nm), straight and unbranched platinum nanowires assembly is demonstrated. On the other hand, it is the objective to go beyond purely electronic applications. An examination of the crystallography of the wires reveals nanoclusters inside the wire with a common crystallographic orientation. The versatility of the wires is illustrated by implementing them into an impedimetric sensor capable of the detection of single nanoscaled objects, such as bacteria<br>Die Zielstellung der vorliegenden Arbeit ist es, die elektrochemische Herstellung von metallischen Nanodrähten zu einer wettbewerbsfähigen Methode zu machen, die sich mit standardisierten Prozessen, wie z. B. der Lithographie messen kann. Dies beinhält auf der einen Seite die Produktion der Nanodrähte als zuverlässige und reproduzierbare Bauteile, die im nanoelektrischen Schaltungsdesign Verwendung finden können. Daher befasst sich diese Arbeit mit einer systematischen Untersuchung der Ursachen für die Verzweigung von Nanodrähten, den notwendigen Bedingungen um gerades Wachstum zu erlangen und mit den Parametern, die Einfluss auf den Durchmesser der Drähte haben. Der Wuchs von sehr dünnen (bis zu 15 nm), geraden und unverzweigten Nanodrähten aus Platin wird gezeigt. Auf der anderen Seite ist es erklärtes Ziel, über rein elektronische Anwendungen hinaus zu gehen. Eine Untersuchung der Kristallographie der Nanodrähte zeigt, dass die Drähte aus Nanopartikeln bestehen, die eine gemeinsame kristallographische Orientierung aufweisen. Die Vielseitigkeit der Drähte wird anhand einer Sensoranwendung gezeigt, mit der es möglich ist, einzelne nanoskalige Objekte (wie z. B. Bakterien) zu detektieren
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Bordui, Peter Frank. "Crystal growth of KTiOPO₄ from high-temperature solution." Thesis, Massachusetts Institute of Technology, 1987. http://hdl.handle.net/1721.1/14962.
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Thesis (Ph. D.)--Massachusetts Institute of Technology, Dept. of Materials Science and Engineering, 1987.<br>MICROFICHE COPY AVAILABLE IN ARCHIVES AND SCIENCE.<br>Vita.<br>Bibliography: leaves 117-119.<br>by Peter Frank Bordui.<br>Ph.D.
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Hodgen, Stephanie Lynne. "Investigation of crystal growth from solution using atomic force microscopy." Thesis, University of Strathclyde, 2005. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.416199.
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Sullivan, Rachel. "Molecules, clusters and crystals : the crystallisation of p-aminobenzoic acid from solution." Thesis, University of Manchester, 2015. https://www.research.manchester.ac.uk/portal/en/theses/molecules-clusters-and-crystals-the-crystallisation-of-paminobenzoic-acid-from-solution(ec826e71-782f-4bb0-9dc2-48cf94a7c941).html.
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Nucleation is a key step in the crystallisation process, where a new crystalline solid phase is created from a supersaturated solution. The applications of crystallisation as a purification and separation technique span many industries, yet still no definitive molecular mechanism for nucleation exists. This PhD is part of a critical mass research project involving researchers from both the Universities of Manchester and Leeds. The aim is to reveal the relationship between structural components of the nucleation transition state, solution phase molecular self-assembly and nano cluster formation, through to critically sized crystalline nuclei which then grow to crystals. All work has been carried out on a small organic molecule, p-aminobenzoic acid (PABA). This PhD has delivered successful characterisation of PABA in the solid and solution state, along with a detailed understanding of its nucleation kinetics and growth rates from a range of solvents. PABA has two enantiotropically related polymorphs, α and β, with the former constructed of carboxylic acid dimers and the latter of a hydrogen bonded tetramer network linking alternate acid and amine functionalities. New determinations of the crystal structures of both forms were submitted to the CCDC with Ref codes of AMBNAC07 and 08 for α and β PABA respectively. A detailed morphological study on both forms of PABA employing modelling and experimental methods has revealed the effect of solvent on the growth habit. In all polar solvents, α PABA displays a more important or slower growing (002) face than the calculated morphology implies. In water, β PABA has a much smaller (101 ̅) face in comparison to β PABA grown from alcohols. Crystallisation experiments demonstrate a clear solvent effect on the appearance of the two polymorphs. From organic solvents only α PABA is obtained, from water both α and β PABA are crystallised. A database search (CCDC) suggests that water may play an important role in the stabilisation of the nucleation transition state for both α and β PABA. This is not possible in organic solvents. Detailed nucleation and crystal growth kinetics have been measured for α PABA at 20°C in water, acetonitrile, ethyl acetate and 2-propanol. A clear solvent trend was observed in both the derived rates of molecular attachment and crystal growth. These were fastest in water, followed by acetonitrile, then ethyl acetate and finally slowest, in 2-propanol. This can be explained by the solvation of the carboxylic acid functional group, where 2-propanol is deemed the most effective solvator of building units in solution and on a crystal surface. This conclusion is supported by the solution FTIR spectroscopy, which clearly confirms strong solvation.
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Ghani, Fatemeh. "Nucleation and growth of unsubstituted metal phthalocyanine films from solution on planar substrates." Phd thesis, Universität Potsdam, 2012. http://opus.kobv.de/ubp/volltexte/2013/6469/.
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Organic solar cells (OSC) are interesting as low cost alternative to conventional solar cells. Unsubstituted Metal-phthalocyanines (Pc) are excellent electron donating molecules for heterojunction OSC. Usually organic solar cells with Pcs are produced by vapor deposition, although solution based deposition (like spin casting) is cheaper and offers more possibilities to control the structure of the film. With solution based deposition several parameters (like temperature, solvent and etc.) affect the self-organized structure formation via nucleation and growth. The reason why vapor deposition is typically used is the poor solubility of the metal-phthalocyanines in most common solvents. Furthermore the process of nucleation and growth of Pc aggregates from solution is not well understood. For preparation of Pc films from solution, it is necessary to find the appropriate solvents, assess the solution deposition techniques, such as dip coating, and spin casting. It is necessary to understand the nucleation and growth process for aggregation/precipitation and to use this knowledge to produce nanostructures appropriate for OSC. This is important because the nanostructure of the films determines their performance.
In this thesis, optical absorption and the stability of 8 different unsubstituted metal Pc’s were studied quantitatively in 28 different solvents. Among the several solution based deposited thin films produced based on this study, copper phthalocyanine (CuPc) dissolved in trifluoroacetic acid (TFA) is chosen as a model system for an in-depth study. CuPc has sufficient solubility and stability in TFA and upon solution processing forms appropriate structures for OSCs. CuPc molecules aggregate into layers of nanoribbons with a thickness of ~ 1 nm and an adjustable width and length. The morphology and the number of deposited layers in the thin films are controlled by different parameters, like temperature and solution concentration. Material properties of CuPc deposited from TFA are studied in detail via x-ray diffraction, UV-Vis and FT-IR spectroscopy. Atomic force microscopy was used to study the morphology of the dried film.
The mechanism of the formation of CuPc nanoribbons from spin casted CuPc/TFA solution in ambient temperature is investigated and explained. The parameters (e.g. solution concentration profile) governing nucleation and growth are calculated based on the spin casting theory of a binary mixture of a nonvolatile solute and evaporative solvent. Based on this and intermolecular interactions between CuPc and substrate a nucleation and growth model is developed explaining the aggregation of CuPc in a supersaturated TFA solution.
Finally, a solution processed thin film of CuPc is applied as a donor layer in a functioning bilayer heterojunction OSC and the influence of the structure on OSC performance is studied.<br>In den vergangenen Jahren wurden kosteneffiziente nasschemische Beschichtungsverfahren für die Herstellung organischer Dünnfilme für verschiedene opto-elektronische Anwendungen entdeckt und weiterentwickelt. Unter anderem wurden Phthalocyanin-Moleküle in photoaktiven Schichten für die Herstellung von Solarzellen intensiv erforscht. Aufgrund der kleinen bzw. unbekannten Löslichkeit wurden Phthalocyanin-Schichten durch Aufdampfverfahren im Vakuum hergestellt. Des Weiteren wurde die Löslichkeit durch chemische Synthese erhöht, was aber die Eigenschaften von Pc beeinträchtigte. In dieser Arbeit wurde die Löslichkeit, optische Absorption und Stabilität von 8 verschiedenen unsubstituierten Metall-Phthalocyaninen in 28 verschiedenen Lösungsmitteln quantitativ gemessen. Wegen ausreichender Löslichkeit, Stabilität und Anwendbarkeit in organischen Solarzellen wurde Kupferphthalocyanin (CuPc) in Trifluoressigsäure (TFA) für weitere Untersuchungen ausgewählt.
Durch die Rotationsbeschichtung von CuPc aus TFA Lösung wurde ein dünner Film aus der verdampfenden Lösung auf dem Substrat platziert. Nach dem Verdampfen des Lösungsmittels, die Nanobändern aus CuPc bedecken das Substrat. Die Nanobänder haben eine Dicke von etwa ~ 1 nm (typische Dimension eines CuPc-Molekül) und variierender Breite und Länge, je nach Menge des Materials. Solche Nanobändern können durch Rotationsbeschichtung oder auch durch andere Nassbeschichtungsverfahren, wie Tauchbeschichtung, erzeugt werden. Ähnliche Fibrillen-Strukturen entstehen durch Nassbeschichtung von anderen Metall-Phthalocyaninen, wie Eisen- und Magnesium-Phthalocyanin, aus TFA-Lösung sowie auf anderen Substraten, wie Glas oder Indium Zinnoxid.
Materialeigenschaften von aufgebrachten CuPc aus TFA Lösung und CuPc in der Lösung wurden ausführlich mit Röntgenbeugung, Spektroskopie- und Mikroskopie Methoden untersucht. Es wird gezeigt, dass die Nanobänder nicht in der Lösung, sondern durch Verdampfen des Lösungsmittels und der Übersättigung der Lösung entstehen. Die Rasterkraftmikroskopie wurde dazu verwendet, um die Morphologie des getrockneten Films bei unterschiedlicher Konzentration zu studieren.
Der Mechanismus der Entstehung der Nanobändern wurde im Detail studiert. Gemäß der Keimbildung und Wachstumstheorie wurde die Entstehung der CuPc Nanobänder aus einer übersättigt Lösung diskutiert. Die Form der Nanobändern wurde unter Berücksichtigung der Wechselwirkung zwischen den Molekülen und dem Substrat diskutiert.
Die nassverarbeitete CuPc-Dünnschicht wurde als Donorschicht in organischen Doppelschicht Solarzellen mit C60-Molekül, als Akzeptor eingesetzt. Die Effizienz der Energieumwandlung einer solchen Zelle wurde entsprechend den Schichtdicken der CuPc Schicht untersucht.
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Soler, Bru Laia. "Liquid-assisted ultrafast growth of superconducting films derived from chemical solutions." Doctoral thesis, Universitat Autònoma de Barcelona, 2019. http://hdl.handle.net/10803/667208.
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L'ús generalitzat de superconductors d'alta temperatura (HTS) en aplicacions a gran escala està, en part, encara limitat per l’elevat cost de fabricació de cintes recobertes (CCs). Amb la intenció d'aconseguir un avanç important per assolir un major rendiment, en aquesta tesi hem desenvolupat una tècnica innovadora que combina els beneficis de Deposició de Solucions Químiques (CSD) a baix cost amb les altes velocitats del creixement cristal·lí a partir de fases líquides. Es basa en la formació d'un líquid transitori derivat de solucions de carboxilats, aprofitant els obstacles cinètics per la cristal·lització de la fase d'equilibri.
En aquesta tesi doctoral, primer expliquem els fonaments del procés que condueix a la cristal·lització de YBa2Cu3O7-δ assistida per un líquid transitori; i després portem a terme una investigació detallada sobre aquesta tècnica. El "proof-of-principle" de la viabilitat d'aquesta nova aproximació es va aconseguir amb la disponibilitat dels forns tipus RTA que permeten rampes fins a 80ºC/s.
Les reaccions implicades en el procés s'observen amb mesures in situ i de microscòpia, entre altres. Primer, la piròlisi resultant de la barreja de propionats de Ba, Cu i Y a baixes temperatures (500ºC) és observada amb espectroscòpia in situ d’infraroig. A continuació, s’utilitza difracció de rajos-X amb llum de sincrotró per revelar les reaccions que tenen lloc per convertir el BaCO3, CuO i Y2O3 en la fase final, així com analitzar la nucleació i el creixement del YBa2Cu3O7-δ des del líquid transitori (TLAG).
Per dur a terme el procés, el pas de deposició es realitza amb mètodes d'impressió d'injecció de tinta o revestiment per rotació. Les característiques de les solucions s'han adaptat a la tècnica de deposició i es correlacionen amb la morfologia de la capa resultant.
A continuació s'han investigat diversos paràmetres per controlar la velocitat de la reacció limitant per l'eliminació del carbonat de bari amb l’objectiu d’evitar la retenció de carboni a les capes gruixudes epitaxials.
Posteriorment, s'estableixen els conceptes bàsics per a la comprensió dels mecanismes de nucleació i creixement del YBCO a partir de TLAG. Amb l'objectiu d'obtenir capes epitaxials de YBCO orientades en l’eix-c, es presenten diverses estratègies per controlar la força de cristal·lització. Els paràmetres rellevants són: la composició de la solució, la pressió d'oxigen, les rampes d’escalfament i les temperatures de creixement. Finalment, les condicions de cristal·lització es correlacionen amb les microestructures i propietats superconductores de les capes resultants.
Es presenten dos camins diferents per dur a terme el creixement mitjançant la formació de líquid. Un és a través d’un augment de temperatura a pressió d'oxígen constant (ruta-Temperatura). L’altre procés consisteix en dos passos (ruta-pO2). Per aquest últim, l'eliminació de BaCO3 es desvincula del creixement de YBCO mitjançant un salt en pO2.
Cal abordar diversos reptes en funció de la ruta. Alguns d’ells són: la reactivitat del líquid amb els substrats degut a la seva naturalesa altament corrosiva, o una mullabilitat inadequada.
Finalment, hem tingut èxit en obtenir pel·lícules fines de YBCO epitaxials d’entre 90-500 nm amb propietats superconductores molt elevades (Tc 90-92K, Jc fins a 5MA/cm2 a 77K), i velocitats de creixement fins a 100 nm/s, augmentat així en un factor 100 la velocitat de creixement de la metodologia de CSD convencional. Aquesta metodologia podria ser traslladada a altres materials.<br>The widespread use of High Temperature Superconductors (HTS) into large scale applications is, in part, still limited by the high costs of coated conductors manufacturing. Aiming for a breakthrough to achieve high throughput, in this thesis we have developed a novel technique that combines the low cost benefits of Chemical Solution Deposition (CSD) with the very high growth rates of crystallization from liquid phases. It relies on the formation of a transient liquid derived from carboxylate solutions, taking advantage of the kinetic hindrances on crystallization to reach the equilibrium phase.
In this dissertation, we first explain the basics of the process that leads to YBa2Cu3O7-δ crystallization assisted by a transient liquid and then we elaborate on the results of our investigation about this technique. The “proof-of-principle” of this new approximation viability has been achieved with the use of rapid thermal annealing furnaces, allowing heating rates up to 80ºC/s.
The reactions involved in the process are observed with in situ measurements and microscopic analyses, among others. First, the pyrolysis of the Ba, Cu and Y propionates mixture at low temperatures (500ºC) is observed with in situ infrared spectroscopy. Then, time resolved X-ray diffraction with synchrotron light is used to reveal the reaction paths to convert the resulting BaCO3, CuO and Y2O3 to the final phase, as well as nucleation and growth of the YBa2Cu3O7-δ film from the transient liquid.
To do so, the deposition step is performed with spin coating or Ink Jet printing methodologies. The solutions characteristics have been adapted to the deposition technique and correlated to the resulting film morphology.
Then, several parameters have been investigated to control the rate limiting BaCO3, elimination reaction in order to avoid carbon retention in the final thick epitaxial films.
Afterwards, the basic concepts for understanding the nucleation and growth mechanisms of YBCO with TLAG are set. With the aim of obtaining c-axis epitaxial YBa2Cu3O7-δ films, several strategies are presented to control the driving force for crystallization. The relevant parameters are solution composition, oxygen pressure, heating ramps and growth temperatures. Finally, the crystallization conditions are correlated to the resulting films microstructure and superconducting performances.
Two different paths are presented to reach TLAG. A direct temperature raise at constant oxygen pressure (Temperature-route), or a two step process (pO2-route). For the latter, BaCO3 elimination is disentangled from YBa2Cu3O7-δ growth by a jump on pO2.
Additionally, several challenges needed to be addressed depending on the route: liquid reactivity with the substrates due to its highly corrosive nature or improper wettability, are some of them.
Finally, we have succeeded in obtaining highly epitaxial YBCO thin films of 90-500nm with very high superconducting performances (Tc 90-92K, Jc up to 5MA/cm2 at self-field and 77K), at growth rates up to 100nm/s, increased by a factor 100 from those reported with conventional CSD. This methodology could be applied to other materials.
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Nerowski, Alexander [Verfasser], Gianaurelio [Akademischer Betreuer] Cuniberti, and Dominique [Akademischer Betreuer] Vuillaume. "Electrochemical Metal Nanowire Growth From Solution / Alexander Nerowski. Gutachter: Gianaurelio Cuniberti ; Dominique Vuillaume. Betreuer: Gianaurelio Cuniberti." Dresden : Saechsische Landesbibliothek- Staats- und Universitaetsbibliothek Dresden, 2013. http://d-nb.info/1068153377/34.
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Davey, Roger J. "The nucleation and growth of crystals from solution - molecular self assembly, materials science and process technology." Thesis, University of Manchester, 2010. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.525976.
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Queraltó, López Albert. "Growth of functional oxide heterostructures from chemical solutions using advanced processing methodologies." Doctoral thesis, Universitat Autònoma de Barcelona, 2015. http://hdl.handle.net/10803/286006.
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En aquesta tesi doctoral, hem explorat innovadores tècniques de processat basades en el dipòsit de solucions químiques per tal de produir heteroestructures d’òxids, mitjançant processos d’autoassemblatge i autoorganització. Essencialment, s’ha dut a terme una profunda investigació dels mecanismes termodinàmics i cinètics involucrats en la nucleació i cristal·lització de diferents heteroestructures d’òxids (nanoilles i capes primes) amb materials com CeO2, LaNiO3, Ba0.8Sr0.2TiO3 i La0.7Sr0.3MnO3 sobre substrats monocristal·lins (Y2O3:ZrO2, LaAlO3, SrTiO3) i tecnològics com silici o cintes metàl·liques recoberts amb capes d’òxids.
Tractaments tèrmics usant rampes d’escalfament ràpides (∼20 ºC/s) han permès separar la nucleació del creixement. En primer lloc, hem reportat que es possible aconseguir cristal·litzar, fins i tot epitaxialment, a baixes temperatures (<500 ºC). També hem determinat el paper que juguen diferents paràmetres de processat (temperatura, rampa d’escalfament i atmosfera), i el tipus i orientació del substrat en les velocitats de nucleació i creixement, com també en la morfologia final del sistema. Anàlisis termodinàmics indiquen que la tensió creada entre capa i substrat té una contribució important en la nucleació i creixement. A més, s’ha pogut veure que la situació de tensió del sistema està altament influenciada per les diferències en l’expansió tèrmica soferta entre capa i substrat.
També hem demostrat que el creixement dels grans segueix un comportament auto-limitat està en gran mesura influenciat per un procés de difusió atòmica activat tèrmicament. Curiosament, la transformació des de material policristal·lí a epitaxial segueix el mateix comportament, i està impulsat per una reducció en les frontes de gra policristal·lines. Les velocitats de creixement del procés (0.01-0.1 nm/s) depenen en gran mesura de com ràpid el material epitaxial creix respecte el policristal·lí. En aquest sentit, hem pogut calcular que els coeficients de difusió atòmica epitaxials són un ordre de magnitud més grans que els policristal·lins, 10-19 i 10-20 m2/s respectivament. S’ha determinat que el gruix de la capa pot influenciar negativament en la velocitat de creixement epitaxial, dificultant la obtenció de capes epitaxials a gruixos grans.
En la mateixa línea, hem implementat i utilizat una metodologia innovadora com és la irradiació làser en condicions atmosfèriques per al creixement d’heteroestructures d’òxids, com a alternativa als tractaments tèrmics. La influència dels mecanismes tèrmics fotoinduïts s’ha avaluat mitjançant simulacions numèriques, usant els paràmetres òptics i termofísics dels diferents materials. Així doncs, hem demostrat la capacitat d’assolir la descomposició de capes metal·lorgàniques precursores, en particular propionats de Ce-Zr, amb temps de processat significativament inferiors i amb resultats equivalents als tractaments tèrmics convencionals. El disseny de patrons micromètrics ha estat possible gràcies al confinament espacial del feix làser. Altrament, també s’ha aconseguit la cristal·lització epitaxial de capes d’òxids sobre substrats monocristal·lins i tecnològics després d’una optimització en les condicions experimentals (fluència, nombre de polsos, temperatura del substrat, etc). S’ha observat que aquest creixement epitaxial és significativament més ràpid comparat amb els tractaments tèrmics (poques mil·lèsimes de segon comparat amb desenes de minuts). La raó d’aquest creixement tant ràpid s’ha atribuït principalment a les temperatures més elevades assolides amb els tractaments làser que tenen una influència rellevant en la difusió atòmica. Tanmateix, hem proposat que altres fenòmens com els grans gradients tèrmics dins les capes (1010 ºC/m), com també efectes fotoquímics derivats del trencament directe dels enllaços químics pels fotons làser poden tenir també una contribució important. Finalment, hem vist que les propietats funcionals de les capes crescudes amb làser són bastant similars a aquelles obtingudes amb tractaments tèrmics.
Les diferents metodologies de creixement combinades amb tècniques de caracterització avançades (microscòpies de força atòmica i electròniques, difracció de raig X, espectroscòpies infraroja-visible-ultravioleta, el·lipsometria) han permès aquest detallat estudi i una millor comprensió dels mecanismes de nucleació i creixement de heteroestructures d’òxids a partir del dipòsit de solucions químiques. Les metodologies i anàlisis desenvolupats han estat fonamentals per al desenvolupament d’aquesta tesi i el seu ús pot ésser traslladat a altres sistemes.<br>In this thesis, we have explored innovative processing methodologies based on the deposition of chemical solutions to produce oxide heterostructures through self-assembling and self-organization processes. Essentially, we performed an in-depth investigation of the thermodynamic and kinetic mechanisms involved in nucleation and crystallization of different oxide heterostructures (nanoislands and thin-films) involving doped-CeO2, LaNiO3, Ba0.8Sr0.2TiO3 and La0.7Sr0.3MnO3 on single crystals (Y2O3:ZrO2 (YSZ), LaAlO3, SrTiO3) and technical substrates like silicon wafers or oxide-buffered stainless steel metallic tapes.
Rapid Thermal Annealing (RTA) furnaces were successfully employed to separate nucleation and coarsening through the use of very fast heating ramps (∼20 ºC/s). First of all, we reported that crystallization and even epitaxial growth can be achieved at very low temperatures (<500 ºC). We also determined the role of the different processing parameters (temperature, heating ramp and atmosphere), substrate type and orientation on nucleation and growth rates of nanoislands and films, and the final morphology. Thermodynamic analyses indicated that strain has an important contribution in nucleation, as well as the final morphology of the system. The strain state of the different heterostructures was found to strongly depend on thermal expansion coefficients of film and substrate.
We also demonstrated that grain coarsening follows a self-limited behavior, and it is highly influenced by a thermally-activated atomic diffusion. Interestingly, we also determined that the transformation from random to epitaxially-oriented material follows the same growth behavior, and it is driven by the reduction of polycrystalline grain boundaries. The growth rate of the process (0.01-0.1 nm/s) highly depends on how fast the epitaxial material grows as compared to the coarsening of polycrystalline grains. We calculated that the epitaxial atomic diffusion coefficients are one order of magnitude larger than polycrystalline coefficients, 10-19 and 10-20 m2/s, respectively. Additionally, we determined that the epitaxial growth rate depends on precursor layer thickness, and this might be a drawback for reaching high epitaxial thick films.
A very new strategy such as Pulsed Laser Annealing at atmospheric conditions has been implemented and employed as an alternative to thermal treatments for the growth of oxide heterostructures. The influence of photo-induced thermal mechanisms has been evaluated through numerical simulations, employing optical and thermo-physical properties of different materials. We have demonstrated the capability to achieve decomposition of CSD precursor films with shorter processing times than in thermal treatments with equivalent results, particularly for the case of Ce-Zr propionates. The spatially-confined nature of the laser beam has also permitted to design micrometric patterned structures. Epitaxial crystallization of oxide films has also been achieved on single crystal and technical substrates after optimization of experimental conditions (fluence, number of pulses, substrate temperature, etc). A significantly faster epitaxial growth compared to thermal treatments has been achieved, i.e. few milliseconds vs tens of minutes. This rapid growth is mostly caused by the higher temperatures developed by laser annealing and influencing atomic diffusion. Additionally, we proposed that other mechanisms should be considered such as temperature gradients developed inside films (1010 ºC/m), as well as photochemical effects caused by direct bond dissociation by the laser photons. The functional properties of laser-grown films have been evaluated and compared with equivalent samples produced using thermal treatments, showing quite similar results.
The different growth methodologies employed combined with advanced characterization techniques (atomic force and scanning transmission electron microscopies, advanced x-ray diffraction measurements, infrared-visible-ultraviolet spectroscopies, ellipsometry) allowed me to perform the profound study undertaken and provided us with a better understanding of nucleation and growth mechanisms of oxide heterostructures from chemical solution deposition. The methodologies and analyses developed have been fundamental for the development of this thesis and their application can be made extensive to other systems.
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Ghani, Fatemeh [Verfasser], and HELMUTH [Akademischer Betreuer] MOEHWALD. "Nucleation and growth of unsubstituted metal phthalocyanine films from solution on planar substrates / Fatemeh Ghani. Betreuer: Helmuth Möhwald." Potsdam : Universitätsbibliothek der Universität Potsdam, 2013. http://d-nb.info/1033036617/34.
Full textBooks on the topic "Growth from solution"
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Enqvist, Yuko. Comprehensive study of crystal growth from solution. Lappeenranta University of Technology, 2004.
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1952-, Myerson Allan S., and United States. National Aeronautics and Space Administration., eds. Concentration dependence of solution shear viscosity and solute mass diffusivity in crystal growth from solutions. National Aeronautics and Space Administration, 1995.
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Abraham, Jay. The sticking point solution: 9 ways to move your business from stagnation to stunning growth in tough economic times. Vanguard Press, 2009.
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Abraham, Jay. The sticking point solution: 9 ways to move your business from stagnation to stunning growth in tough economic times. Vanguard Press, 2009.
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Brian, Lent, ed. Single crystal growth of semiconductors from metallic solutions. Elsevier, 2007.
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United States. National Aeronautics and Space Administration., ed. Annual technical report (period, January 1, 1993 till December 31, 1993) on direct observation of crystal growth from solution using optical investigation of a growing crystal face: Submitted to Lewis Research Center, National Aeronautics and Space Administration ... National Aeronautics and Space Administration, 1994.
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United States. National Aeronautics and Space Administration., ed. Annual technical report (period, January 1, 1993 till December 31, 1993) on direct observation of crystal growth from solution using optical investigation of a growing crystal face: Submitted to Lewis Research Center, National Aeronautics and Space Administration ... National Aeronautics and Space Administration, 1994.
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Mothers & Others for a Livable Planet, Inc., ed. The way we grow: Good-sense solutions for protecting our families from pesticides in food. Berkley Books, 1993.
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Eurybiades, Busenberg, and Geological Survey (U.S.), eds. Data on the crystal growth of calcite from calcium bicarbonate solutions at 34p0sC and CO2 partial pressures of 0.101, 0.0156 and 0.00102 atmospheres. U.S. Dept. of the Interior, U.S. Geological Survey, 1999.
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Eurybiades, Busenberg, and Geological Survey (U.S.), eds. Data on the crystal growth of calcite from calcium bicarbonate solutions at 34⁰C and CO2 partial pressures of 0.101, 0.0156 and 0.00102 atmospheres. U.S. Dept. of the Interior, U.S. Geological Survey, 1999.
Find full textBook chapters on the topic "Growth from solution"
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Chernov, A. A., L. N. Rashkovich, I. L. Smol’skii, Yu G. Kuznetsov, A. A. Mkrtchyan, and A. I. Malkin. "Growth of KDP-Group Crystals from Solution." In Growth of Crystals. Springer US, 1988. http://dx.doi.org/10.1007/978-1-4615-7125-4_4.
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Punin, Yu O. "Formation of Autodeformation Defects in Crystal Growth from Solution." In Growth of Crystals. Springer US, 1987. http://dx.doi.org/10.1007/978-1-4615-7122-3_11.
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Regel’, L. L. "Microgravity Growth of Crystals from Aqueous Solution." In Materials Processing in Space. Springer US, 1990. http://dx.doi.org/10.1007/978-1-4684-1683-1_5.
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Potapenko, S. Yu. "Morphological Instability and Inclusion Formation During Crystal Growth from a Flowing Solution." In Growth of Crystals. Springer US, 2002. http://dx.doi.org/10.1007/978-1-4615-0537-2_10.
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Eid, Jessica, Jean Louis Santailler, Bernard Ferrand, et al. "Growth of Cubic Silicon Carbide Crystals from Solution." In Silicon Carbide and Related Materials 2005. Trans Tech Publications Ltd., 2006. http://dx.doi.org/10.4028/0-87849-425-1.123.
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Aggarwal, Mohan D., Ashok K. Batra, Ravindra B. Lal, Benjamin G. Penn, and Donald O. Frazier. "Bulk Single Crystals Grown from Solution on Earth and in Microgravity." In Springer Handbook of Crystal Growth. Springer Berlin Heidelberg, 2010. http://dx.doi.org/10.1007/978-3-540-74761-1_17.
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Magid, L. J., R. Triolo, E. Caponetti, and J. S. Johnson. "Small-Angle Neutron Scattering from Aqueous Solutions of C12E6 and C12E8: Critical Fluctuations and Micellar Growth." In Surfactants in Solution. Springer US, 1986. http://dx.doi.org/10.1007/978-1-4613-1831-6_11.
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Suzuki, Kenji, Kazuhiko Kusunoki, Nobuyoshi Yashiro, Nobuhiro Okada, Kazuhito Kamei, and Akihiro Yauchi. "Solution Growth of Single Crystalline 6H-SiC from Si-Ti-C Ternary Solution." In Innovation in Ceramic Science and Engineering. Trans Tech Publications Ltd., 2007. http://dx.doi.org/10.4028/0-87849-454-5.89.
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Bedarida, F. "Crystal Growth from Transparent Solution - Two Methods to Study Crystal Growth and Hydrodynamics of the Solution at a Time." In Crystal Growth in Science and Technology. Springer US, 1989. http://dx.doi.org/10.1007/978-1-4613-0549-1_12.
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Grzegory, I., M. Boćkowski, and S. Porowski. "GaN Bulk Substrates Grown under Pressure from Solution in Gallium." In Bulk Crystal Growth of Electronic, Optical & Optoelectronic Materials. John Wiley & Sons, Ltd, 2010. http://dx.doi.org/10.1002/9780470012086.ch6.
Full textConference papers on the topic "Growth from solution"
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Gao, Jie, and David J. Quesnel. "Stress Corrosion Cracking of Sensitized AA5083 in NaCl Solution." In CORROSION 2011. NACE International, 2011. https://doi.org/10.5006/c2011-11284.
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Abstract In this study, commercial AA5083 aluminum alloy was sensitized at 175oC in order to create a two-phase microstructure that is highly susceptible to stress corrosion cracking (SCC). To characterize the SCC behavior of these sensitized AA5083 alloy in NaCl solution, open circuit continuous immersion SCC tests were conducted on pre-cracked double cantilever beam (DCB) specimens with an initial stress intensity factor (KI) of 15 ksiin (16.5 MPam) in NaCl solutions with five different concentrations, i.e. 0.01, 0.1, 0.6, 1, and 3 mol/L. Three SCC characteristics, incubation time, initial crack growth rate, and total crack growth, were found strongly dependent on solution concentration: incubation time decreased with increasing NaCl concentration, while both initial crack growth rate and total crack growth increased with solution concentration. A linear relationship between initial crack growth rate and NaCl concentration, as well as between total crack growth and NaCl concentration, was also found on specimens sensitized for 10 days (240 hours). Since the growth of cracks under fixed loading line displacement decreases the applied K, the arrest of cracks that limits the total crack growth may be interpreted as a concentration dependent threshold stress intensity, KISCC. Fracture surfaces produced by SCC in NaCl solutions with different concentrations and on different values of K, when investigated by scanning electron microscopy, all demonstrated intergranular cracking with similar characteristics. Discussion centers on relative contributions to SCC from mechanical driving forces and chemical driving forces.
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Amjad, Zahid. "Seeded Growth of Calcium-Containing Scale Forming Minerals in the Presence of Inhibitors." In CORROSION 1988. NACE International, 1988. https://doi.org/10.5006/c1988-88421.
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Abstract The conventional seeded growth technique has been used to study the influence of solution pH in the range 2.8 to 8.8 on the crystal growth of calcium sulfate dihydrate (CaSO4∙2H2O, gypsum) from stable supersaturated solutions in the presence of polyacrylic acids. Results indicate that at a constant solution pH, crystal growth of gypsum in the presence of polyacrylic acid is preceeded by an initial slow growth reaction, hereafter called induction period, following which crystal growth of gypsum proceeds with a rate close to that in pure solution. Kinetic data collected as a function of solution pH in the range 2.8 to 8.6 suggest that solution pH has a marked effect on the induction period. The observed dependence of induction period on solution pH may be explained in terms of the degree of ionization of polyacrylic acid. The influence of commonly encountered scales as nucleators for gypsum growth has also been investigated using the conventional seeded growth technique. Kinetic data of this study indicate that CaCO3 is an effective nucleator. Results on the influence of several products on the CaCO3 induced gypsum crystal growth show marked dependence on product composition. In the case of calcium phosphate crystal growth, the constant composition technique has been used to study the influence of crystal growth inhibitors. A simple Langmuir adsorption model has been proposed to account for the marked inhibitory influence exhibited by an acrylic acid-based copolymer.
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Huggins-Gonzalez, Angeire S., Ramgopal Thodla, Feng Gui, Bostjan Bezensek, and Brian Chambers. "Effect of Loading Profile and Sour Environment on Cracking Behavior of C110." In CONFERENCE 2023. AMPP, 2023. https://doi.org/10.5006/c2023-19401.
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Abstract Crack initiation and propagation in sour environments have been studied as part of understanding sulfide stress cracking mechanism. This research evaluated crack growth rate of two heats of C110 under different loading modes and exposed to two different solutions with different buffer capacities (NACE Solution B and C). There was no effect of decreasing K profile on the crack growth rate behavior in either environment on either heat. The Kth estimated from DCB tests for heat I in solution C were consistent with the values measured using the constant K test method. However, in solution B, stable cracking was observed under constant K conditions at K values lower than the Kth measured in the DCB tests. The difference in the crack growth rate behavior between solution B and solution C is likely associated with the different buffer capacities of the two solutions. Solution B is a more stable buffer (acetic acid/sodium acetate) and hence is likely to support significantly higher metal dissolution rates by supporting higher cathodic current densities on the crack flanks.
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Liu, Sue, and Digby D. Macdonald. "Fracture of AISI 4340 Steel in Concentrated Sodium Hydroxide Solution." In CORROSION 2001. NACE International, 2001. https://doi.org/10.5006/c2001-01236.
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Abstract Fracture of AISI 4340 steel in concentrated sodium hydroxide solution has been monitored by measuring the coupling current that flows between the crack and the external surfaces. The results clearly demonstrate that positive current flows from the crack to the external cathodes (through the solution) during crack growth of AISI 4340 steel in concentrated (6 to 12 M) sodium hydroxide solution at 70 °C. The (electron) coupling current contains periodic noise that is attributed to fracture events occurring at the crack front, with the amplitude of the noise and the mean current increasing with crack growth rate. The characteristic shape of the individual transients in the noise at lower SCC crack growth rate is rapid drop followed by slow recovery. The form of the noise in the coupling current during SCC at high NaOH concentration (8 M and 12 M) is attributed to overlap of many cracks propagating simultaneously through micro fracture events along grain boundaries. The discrete events are postulated to be hydrogen induced, and the mechanism of caustic cracking of AISI 4340 steel is considered to be hydrogen embrittlement along grain boundaries. Measurement of the electrochemical noise is shown to be capable of detecting and distinguishing between uniform corrosion and stress corrosion cracking in the steel/NaOH system.
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Amjad, Z., and W. F. Masler. "The Inhibition of Calcium Sulfate Dihydrate Crystal Growth by Polyacrylates and the Influence of Molecular Weight." In CORROSION 1985. NACE International, 1985. https://doi.org/10.5006/c1985-85357.
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Abstract A seeded growth method has been used to study the influence of low molecular weight (MW 710-12,800) polyacrylates on the crystallization of calcium sulfate di hydrate from stable supersaturated solution at temperature ranging from 30-50°C. The results. indicate that the crystallization in the presence of polyacrylates is preceded by an induction period following which crystal growth of CaSO4·2H2O proceeds with a rate close to that in pure supersaturated solution. Temperature changes, polyacrylate concentration, and polymer molecular weight greatly affect the duration of the induction period. The optimum effectiveness as determined by induction period duration occurs with a polyacrylate having a molecular weight (Mw) of 2,100. The observed induction periods for the growth of CaSO4·2H2O in the presence of polyacrylates strongly suggest that the polymer is incorporated into the crystal lattice as the crystal grows.
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Andresen, Peter L., and Lisa M. Young. "Crack Tip Microsampling & Growth Rate Measurements in Low Alloy Steel in High Temperature Water." In CORROSION 1995. NACE International, 1995. https://doi.org/10.5006/c1995-95156.
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Abstract The importance of dissolution of MnS inclusions in environmentally assisted cracking (EAC) of pressure vessel steels in high temperature water is well recognized. However, no direct measurement of the crack tip chemistry that develops during EAC has ever been performed, and only estimates exist for the dissolution rate of MnS and the resulting sulfur levels in the crack. In this manuscript, microsampling of the crack tip solution in A533B low alloy steel (0.013% S) exposed to constant and cyclic loading in 288°C water under various test conditions has been used to obtain direct measurements of the crack tip sulfur concentration, while simultaneously monitoring crack length. A reversing direct current potential drop method was used to continuously monitor crack length. Ion chromatography (IC) and inductively coupled plasma (ICP) were used to measure dissolved sulfur species in the microsampled solutions. Most experiments involved varying the corrosion potential (from = 0.12 to ≈ −0.5 Vshe) by changing the dissolved oxygen concentration between 10 ppm and 0 ppm (nitrogen deaerated) in high purity water. At 10 ppm oxygen, high crack growth rates were observed and the microsampled solutions contained between 1 and 2 ppm sulfur, about 10 times higher than at 0 ppm oxygen, where crack growth rates were low. Measurements of the room temperature solutions showed that most sulfur was present as sulfate, although in the high temperature deaerated water in the crack, MnS undoubtedly dissolves to form HS− and H2S. Decreasing the loading frequency from 10−4 to 10−5 Hz also lowered both the crack growth rate and the crack tip sulfur concentration. Very high microsampling rates effectively flushed the crack tip chemistry, decreasing the crack tip sulfur content and crack growth rate. This research provides a technique for directly determining the effects of MnS inclusion dissolution, corrosion potential, (bulk) solution impurities, solution flow rate, and loading conditions on crack tip chemistry and, in turn, on crack growth rate and thus can contribute significantly to the fundamental understanding of EAC.
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Bogdanov, R. I., A. I. Marshakov, and V. E. Ignatenko. "Hydrogen Peroxide Effect on Crack Growth Rate in X70 Pipeline Steel in Weak Acid Solution." In CORROSION 2016. NACE International, 2016. https://doi.org/10.5006/c2016-07470.
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Abstract It is known that stress corrosion cracking (SCC) of pipeline steels appear in anaerobic soils, which is probably related to activity of sulphate-reducing bacteria and formation of hydrogen sulphide. Oxygen and other oxidants direct influence on crack growth in pipeline steels data are few and controversial. This work describes the results of corrosion - mechanical tests on beam specimens under static stress. Specimens were made from X70 steel grade. Electrochemical measurements were carried out in a Devanathan – Stachurski cell using foil mild steel membranes. The citrate buffer solution (pH 5.5) was background electrolyte. Hydrogen peroxide (H2O2), model additive of oxidative type, was injected into background electrolyte. It was found that the presence of Н2О2 in a relatively small concentration (5 mM) results in the deceleration of the crack growth. With an increase in concentration of hydrogen peroxide, the crack growth rate increases. The phenomenon is explained by the effect of hydrogen peroxide on the penetration rate of hydrogen into the metal, which in turn determines the dissolution rate of iron.
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De Turris, Antonio, Matilde de Romero, Tesfaalem G. Haile, Sankara Papavinasam, and W. Douglas. "Correlation between the Growth of a Mixed Culture of Sulphate-Reducing Bacteria Isolated from Produced Water and the Corrosion of Carbon Steel." In CORROSION 2012. NACE International, 2012. https://doi.org/10.5006/c2012-01126.
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Abstract In this work the corrosion of carbon steel exposed to a mixed culture of sulphate-reducing bacteria (SRB) isolated from a Venezuelan industry crude oil field was investigated. The optimum conditions for SRB growth were established and growth curves for 1 v% and 10 v% of inoculum in synthetic produced water (SPW) were constructed. Changes in solution pH, iron content, sulphide concentration, and sulphate concentration were measured. The growth of sessile and planktonic mixed culture of SRB was found to correlate with corrosion rate and corrosion morphology.
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Cooper, K. R., R. G. Kelly, and E. L. Colvin. "The Correlation between Crack Chemistry and Crack Growth Behavior of 7xxx Series Aluminum Alloys: A Comparison of Field and Laboratory Tests." In CORROSION 1999. NACE International, 1999. https://doi.org/10.5006/c1999-99153.
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Abstract The crack growth kinetics and solution chemistry developed within environment-assisted cracks (EAC) grown in laboratory tests and long-term field exposures of high-strength Al-Zn-Mg-Cu alloys were assessed. For both test programs, peak-aged (T651) material exhibited crack growth kinetics 103 to 104 times that of overaged (T7X51). Laboratory crack growth studies in aqueous CrO42-/Cl- environments demonstrated the characteristic enhanced resistance of overaged Al-Zn-Mg-Cu alloys to intergranular EAC crack propagation relative to peak-aged tempers. The laboratory environment is suitable for alloy development and mechanistic studies of environment-assisted cracking in these alloys. Cracks within fracture specimens exposed to an industrial atmosphere contained predominately chloride and sulfate with minor amounts of nitrate, nitrite and organic acids. The dominant cations found were aluminum, zinc and magnesium dissolved from the alloy in addition to sodium and potassium from the external atmosphere. Environment-assisted crack growth behavior during atmospheric exposure was not correlated to the crack chemistry. The crack solution of field-exposed specimens was similar for peak-aged and overaged material, attaining a pH of 3 to 3.8. The crack solution of these specimens was probably dominated by crevice corrosion. In contrast to the atmospheric tests, the low corrosiveness of the laboratory environment facilitated differentiation of peak-aged and overaged crack chemistry. Whereas peak-aged material developed an acidic, concentrated Al-salt solution at the crack tip, overaged material showed little alteration of the crack environment from that of the external solution.
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Morris, Kevin. "“All Fouled Up” – An Innovative Solution." In SSPC 2015 Greencoat. SSPC, 2015. https://doi.org/10.5006/s2015-00040.
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Abstract Within the Wastewater Treatment process the growth of soft fouling materials (algae) create problems such as Total Suspended Solids issues, false BOD readings, clogged pumps and reduced flow rates through the weirs of clarifiers. Furthermore, dead or dying algae can cause additional odor concerns. This phenomenon has cost municipalities and tax payer’s untold amounts of money due to the required maintenance dollars spent to correct this problem. This paper will present the readers with a view of some of the previous methods used to correct this problem and the effects caused by these methods. It will also discuss how the transfer of technology from another market segment is providing the industry with a solution that presents no side effects that will have to be addressed in the future and the thought process and testing that lead to this coating technology being considered as a potential solution. Finally the author will tie the paper into a case study where silicone foul release coatings have been used to remediate the issues with soft fouling on a clarifier launder trough in a large municipality in the U.S.
Reports on the topic "Growth from solution"
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Watson, Mark, Martyn Wilmott, and Brian Erno. GRI-96-0452_2 Stress Corrosion Cracking Under Field Simulated Conditions II. Pipeline Research Council International, Inc. (PRCI), 1997. http://dx.doi.org/10.55274/r0011974.
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The pH of solutions found under disbonded polyethylene tape coatings in the field is generally in the range of 6.5 to 7.5. Electrochemically determining corrosion rates for pipeline steels exposed to neutral pH solutions in this pH range indicate that corrosion rates are too low to account for the observed crack growth rates from field excavation programs. This suggests that for the SCC process to be based on a simple dissolution mechanism then the pH at the crack tip would have to be lower than the bulk solution pH. A computer model was developed to determine solution chemistry changes within an SCC crack under anaerobic conditions as a function of time The numerical simulation model showed that the pH at a crack tip is lower by at least one pH unit than the trapped electrolyte outside the crack. A second thermodynamic model was used to show that under appropriate conditions dilute groundwater can be converted to a concentrated carl ornately bicarbonate solution. High temperatures were not required to concentrate on this solution. The concentration of this electrolyte under coal tar or asphalt coatings can occur by a cyclical process in which groundwater levels fluctuate and in tum influence the ability of cathodic protection to reach the steel surface. The high pH is generated by effective cathodic protection and the carbonate concentration is developed by absorption of CO2 from soil gases.
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Ármás, Julianna, Ferenc Németh, and Anna Orosz. Non-papers on border changes in the Western Balkans: promise of an easy solution or a hazardous game? Külügyi és Külgazdasági Intézet, 2021. http://dx.doi.org/10.47683/kkielemzesek.ke-2021.43.
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The idea of redrawing borders in the Western Balkans is a frequently discussed topic. Beside a lack of support and feasibility making the implementation of such plans impracticable, the idea also has negative implications. While border changes would significantly hinder the economic growth, inter-ethnic relations, and EU integration of the region, the real issues that the Western Balkans face would not be solved, either. This paper presents the main problems regarding the idea of redrawing borders from local, regional, and global perspectives.
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Donehower, Gretchen. Gender and the Total Work of Older Workers in Asia. Asian Development Bank, 2023. http://dx.doi.org/10.22617/wps230213-2.
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In Asia, aging countries with slow population growth worry about a lack of workers in the future and see older people’s labor as a potential solution. However, this leaves out the work that many older people already do: unpaid care work. Drawing on data from Bangladesh, India, Mongolia, and Thailand, estimates in this paper show that older people, especially older women, are doing a great deal of work caring for others. Policymakers should take this unpaid care work into account when designing policy around older people’s market labor.
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Hadley, Isabel. PR164-205102-R01 Application of Probabilistic Fracture Mechanics to Engineering Critical Assessment. Pipeline Research Council International, Inc. (PRCI), 2021. http://dx.doi.org/10.55274/r0012093.
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This report summarizes the results of a series of deterministic and probabilistic fracture and fatigue calculations carried out in order to: ? Demonstrate that ProCW correctly implements probabilistic ECA, eg by comparing selected deterministic and probabilistic calculations, ? Show the effect of the choice of K-solution on the fatigue life and POF of pipes containing a circumferential flaw, ? Implement a two-stage probabilistic model of fatigue crack growth, in both air and marine environments, ? Consider the effects of modelling the fatigue crack growth threshold probabilistically, ? Demonstrate the use of ProCW for a representative riser geometry and a complex loading spectrum, ? For the same riser geometry/loading scenario, compare the POF implied by the use of design fatigue safety factors given in DNVGL-ST-F101 [2], DNVGL-RP-F204 [3] and DNVGL-RP-F201 [4] with the POF calculated directly from probabilistic calculations. There is a related webinar.
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Walmsley, Terrie. Long Run Simulations With GTAP: Illustrative Results from APEC Trade Liberalisation. GTAP Technical Paper, 2000. http://dx.doi.org/10.21642/gtap.tp09.
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In static applied general equilibrium models, the exogenous/endogenous split between variables (or closure) is used to infer the time frame over which the effects of a shock are simulated. This paper introduces a long-run closure for the GTAP model (Hertel and Tsigas, 1997) and uses this closure to simulate and compare the short-run and long-run effects of Asia-Pacific trade liberalisation. The approach explored here incorporates some relatively minor changes to existing GTAP theory in order to define a steady state in which growth rates of all real variables are uniform. Such uniformity must apply in the initial database (as well as in the post-shock solution). So to implement the new long run in GTAP a new initial database must first be created. Details concerning the creation of the new database are given, and results under the new approach are compared with those obtained under the old. The emphasis of this paper is on the development of a long-run closure in which the percentage change form equations of the model and the relationships between the levels variables in the GTAP database are consistent. Further research is required into these types of long-run closures to incorporate changes in ownership of capital to ensure that changes in welfare are adequately modelled. In the results reported here, GDP is not a useful guide to national welfare. The long-run closures introduced here are also compared with another comparative static long-run closure developed for GTAP by Francois, MacDonald and Nordström (1996). Technical Paper Number 9 can be downloaded in PDF format. To print this you will need the Adobe Acrobat Reader. For those interested in replicating the results in this technical paper, an associated zip file can be downloaded. The zip file includes a readme file with detailed instructions.
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Short, Samuel. Alternatives to single-use plastics in food packaging and production. Food Standards Agency, 2023. http://dx.doi.org/10.46756/sci.fsa.taf512.
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This rapid evidence assessment undertaken by RSM UK Consulting LLP (RSM) and Dr Samuel Short (University of Cambridge) aimed to develop an understanding of the alternatives to single-use plastics in food packaging and production in terms of their risks and opportunities, as well as potential future developments. Literature from within and beyond the UK was gathered from academic databases and reports published by government and non-governmental organisations such as environmental charities. Evidence from the literature was supplemented by findings from a workshop with experts in the field from a variety of industries such as academia, manufacturing, and government. Two broad groups of alternatives were established: material/product alternatives (traditional materials, natural fibres, biopolymers synthesised from biomass, biopolymers synthesised from bioderived monomers, biopolymers produced by microorganisms) and, and system/process alternatives (reducing, reusing, and recycling food packaging and, active and intelligent packaging). These alternatives and systems vary considerably in terms of their properties, such as effectiveness as a barrier to moisture or contamination, convenience for consumers, production costs, and potential for commercialisation. Our review also highlighted gaps in the current knowledge, for example in terms of consumer acceptance and carbon footprint at each stage of their life cycle. The capacity to produce bioplastics (i.e. biopolymers that look and feel similar to conventional plastics but are made from natural materials rather than fossil fuels and are biodegradable or compostable) is anticipated to increase globally from 2.1 million tonnes in 2019 to 6.3 million tonnes by 2027. This growth appears to be enabled by increased consumer awareness of environmental issues and existing regulation and legislation encouraging the development and establishment of a circular economy. However, there are barriers that may challenge this growth. These include already established industry regimes, high production cost of novel materials and a lack of waste management guidance. Overall, fossil-based conventional plastics are a very cheap, versatile material compared to the alternatives currently being developed and tested. Because of this, they might remain the preferred industry choice for certain applications, while alternatives continue to be optimised and commercially scaled. To add to this, the reviewed evidence suggests that there is unlikely to be one single solution to the single-use plastics problem. The solution will likely draw on a range of materials and systems depending on food type and context.
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Lahav, Ori, Albert Heber, and David Broday. Elimination of emissions of ammonia and hydrogen sulfide from confined animal and feeding operations (CAFO) using an adsorption/liquid-redox process with biological regeneration. United States Department of Agriculture, 2008. http://dx.doi.org/10.32747/2008.7695589.bard.
Full textAbstract:
The project was originally aimed at investigating and developing new efficient methods for cost effective removal of ammonia (NH₃) and hydrogen sulfide (H₂S) from Concentrated Animal Feeding Operations (CAFO), in particular broiler and laying houses (NH₃) and hog houses (H₂S). In both cases, the principal idea was to design and operate a dedicated air collection system that would be used for the treatment of the gases, and that would work independently from the general ventilation system. The advantages envisaged: (1) if collected at a point close to the source of generation, pollutants would arrive at the treatment system at higher concentrations; (2) the air in the vicinity of the animals would be cleaner, a fact that would promote animal growth rates; and (3) collection efficiency would be improved and adverse environmental impact reduced. For practical reasons, the project was divided in two: one effort concentrated on NH₃₍g₎ removal from chicken houses and another on H₂S₍g₎ removal from hog houses. NH₃₍g₎ removal: a novel approach was developed to reduce ammonia emissions from CAFOs in general, and poultry houses in particular. Air sucked by the dedicated air capturing system from close to the litter was shown to have NH₃₍g₎ concentrations an order of magnitude higher than at the vents of the ventilation system. The NH₃₍g₎ rich waste air was conveyed to an acidic (0<pH<~5) bubble column reactor where NH₃ was converted to NH₄⁺. The reactor operated in batch mode, starting at pH 0 and was switched to a new acidic absorption solution just before NH₃₍g₎ breakthrough occurred, at pH ~5. Experiments with a wide range of NH₃₍g₎ concentrations showed that the absorption efficiency was practically 100% throughout the process as long as the face velocity was below 4 cm/s. The potential advantages of the method include high absorption efficiency, lower NH₃₍g₎ concentrations in the vicinity of the birds, generation of a valuable product and the separation between the ventilation and ammonia treatment systems. A small scale pilot operation conducted for 5 weeks in a broiler house showed the approach to be technically feasible. H₂S₍g₎ removal: The main goal of this part was to develop a specific treatment process for minimizing H₂S₍g₎ emissions from hog houses. The proposed process consists of three units: In the 1ˢᵗ H₂S₍g₎ is absorbed into an acidic (pH<2) ferric iron solution and oxidized by Fe(III) to S⁰ in a bubble column reactor. In parallel, Fe(III) is reduced to Fe(II). In the 2ⁿᵈ unit Fe(II) is bio-oxidized back to Fe(III) by Acidithiobacillus ferrooxidans (AF).In the 3ʳᵈ unit S⁰ is separated from solution in a gravity settler. The work focused on three sub-processes: the kinetics of H₂S absorption into a ferric solution at low pH, the kinetics of Fe²⁺ oxidation by AF and the factors that affect ferric iron precipitation (a main obstacle for a continuous operation of the process) under the operational conditions. H₂S removal efficiency was found higher at a higher Fe(III) concentration and also higher for higher H₂S₍g₎ concentrations and lower flow rates of the treated air. The rate limiting step of the H₂S reactive absorption was found to be the chemical reaction rather than the transition from gas to liquid phase. H₂S₍g₎ removal efficiency of >95% was recorded with Fe(III) concentration of 9 g/L using typical AFO air compositions. The 2ⁿᵈ part of the work focused on kinetics of Fe(II) oxidation by AF. A new lab technique was developed for determining the kinetic equation and kinetic parameters (KS, Kₚ and mₘₐₓ) for the bacteria. The 3ʳᵈ part focused on iron oxide precipitation under the operational conditions. It was found that at lower pH (1.5) jarosite accumulation is slower and that the performance of the AF at this pH was sufficient for successive operation of the proposed process at the H₂S fluxes predicted from AFOs. A laboratory-scale test was carried out at Purdue University on the use of the integrated system for simultaneous hydrogen sulfide removal from a H₂S bubble column filled with ferric sulfate solution and biological regeneration of ferric ions in a packed column immobilized with enriched AFbacteria. Results demonstrated the technical feasibility of the integrated system for H₂S removal and simultaneous biological regeneration of Fe(III) for potential continuous treatment of H₂S released from CAFO. NH₃ and H₂S gradient measurements at egg layer and swine barns were conducted in winter and summer at Purdue. Results showed high potential to concentrate NH₃ and H₂S in hog buildings, and NH₃ in layer houses. H₂S emissions from layer houses were too low for a significant gradient. An NH₃ capturing system was designed and tested in a 100-chicken broiler room. Five bell-type collecting devices were installed over the litter to collect NH₃ emissions. While the air extraction system moved only 10% of the total room ventilation airflow rate, the fraction of total ammonia removed was 18%, because of the higher concentration air taken from near the litter. The system demonstrated the potential to reduce emissions from broiler facilities and to concentrate the NH₃ effluent for use in an emission control system. In summary, the project laid a solid foundation for the implementation of both processes, and also resulted in a significant scientific contribution related to AF kinetic studies and ferrous analytical measurements.
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Uni, Zehava, and Peter Ferket. Enhancement of development of broilers and poults by in ovo feeding. United States Department of Agriculture, 2006. http://dx.doi.org/10.32747/2006.7695878.bard.
Full textAbstract:
The specific objectives of this research were the study of the physical and nutritional properties of the In Ovo Feeding (IOF) solution (i.e. theosmostic properties and the carbohydrate: protein ratio composition). Then, using the optimal solution for determining its effect on hatchability, early nutritional status and intestinal development of broilers and turkey during the last quarter of incubation through to 7 days post-hatch (i.e. pre-post hatch period) by using molecular, biochemical and histological tools. The objective for the last research phase was the determination of the effect of in ovo feeding on growth performance and economically valuable production traits of broiler and turkey flocks reared under practical commercial conditions. The few days before- and- after hatch is a critical period for the development and survival of commercial broilers and turkeys. During this period chicks make the metabolic and physiological transition from egg nutriture (i.e. yolk) to exogenous feed. Late-term embryos and hatchlings may suffer a low glycogen status, especially when oxygen availability to the embryo is limited by low egg conductance or poor incubator ventilation. Much of the glycogen reserve in the late-term chicken embryo is utilized for hatching. Subsequently, the chick must rebuild that glycogen reserve by gluconeogenesis from body protein (mostly from the breast muscle) to support post-hatch thermoregulation and survival until the chicks are able to consume and utilize dietary nutrients. Immediately post-hatch, the chick draws from its limited body reserves and undergoes rapid physical and functional development of the gastrointestinal tract (GIT) in order to digest feed and assimilate nutrients. Because the intestine is the nutrient primary supply organ, the sooner it achieves this functional capacity, the sooner the young bird can utilize dietary nutrients and efficiently grow at its genetic potential and resist infectious and metabolic disease. Feeding the embryo when they consume the amniotic fluid (IOF idea and method) showed accelerated enteric development and elevated capacity to digest nutrients. By injecting a feeding solution into the embryonic amnion, the embryo naturally consume supplemental nutrients orally before hatching. This stimulates intestinal development to start earlier as was exhibited by elevated gene expression of several functional genes (brush border enzymes an transporters , elvated surface area, elevated mucin production . Moreover, supplying supplemental nutrients at a critical developmental stage by this in ovo feeding technology improves the hatchling’s nutritional status. In comparison to controls, administration of 1 ml of in ovo feeding solution, containing dextrin, maltose, sucrose and amino acids, into the amnion of the broiler embryo increased dramatically total liver glycogen in broilers and in turkeys in the pre-hatch period. In addition, an elevated relative breast muscle size (% of broiler BW) was observed in IOF chicks to be 6.5% greater at hatch and 7 days post-hatch in comparison to controls. Experiment have shown that IOF broilers and turkeys increased hatchling weights by 3% to 7% (P<0.05) over non injected controls. These responses depend upon the strain, the breeder hen age and in ovo feed composition. The weight advantage observed during the first week after hatch was found to be sustained at least through 35 days of age. Currently, research is done in order to adopt the knowledge for commercial practice.
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Arumugam, Udayansankar, Mimoun Elboujdaini, Ming Gao, and Ramiro Vanoye. PR-328-133702-R02 F-S Fatigue Testing of Crack-in-Dent with Framework for Life Prediction. Pipeline Research Council International, Inc. (PRCI), 2019. http://dx.doi.org/10.55274/r0011628.
Full textAbstract:
ASME B31.8 states that "Dents that contain stress corrosion cracking or other cracks are injurious to the pipeline" and therefore, requires immediate attention by the Operators. Dent containing crack fields (colonies) are often observed in liquid pipelines. The recently completed PRCI research project MD-1N "Study of the Mechanism for Cracking in Dents in a Crude Oil Pipeline" showed evidence of a mechanism for fatigue cracking. The crack growth rate as a function of stress intensity factor was estimated using the measured spacings of fatigue striations from fracture surfaces based on the assumption that the formation of fatigue striations on a cycle-by-cycle basis. However, due to the lack of full-scale fatigue crack growth data, the success was limited. This gap prompted PRCI to launch a full-scale experimental investigation of crack growth rates of cracks in dents under cyclic pressure load in the simulated groundwater NS4 environment (PRC-328-133702, MD-1Q). The objective of the study was to determine the crack growth rate as a function of stress intensity factor, the number of cycles to failure, and the failure modes of cracks in dents. The test results would be used to evaluate the validity of cycle-by-cycle based assumption for crack growth rate estimation from the measured fatigue-striation-spacing. The investigation was also aimed at establishing a framework for remaining fatigue life prediction of cracks in dents in liquid pipelines. This framework would benefit liquid pipeline Operators to manage better the integrity of dents associated with corrosion fatigue cracking in groundwater. A total of six pipe samples containing cracks in shallow dents excavated from a retired 24-inch diameter liquid transmission pipeline were available and used for the full-scale fatigue tests. The test system developed under the project consisted of four components: (1) a computer-controlled hydraulic pressure cycling system, (2) an environment chamber containing a simulated groundwater NS4 solution mounted on the pipe in around the dent region to provide a simulated field environment condition; (3) real-time crack growth monitoring systems including direct cur-rent potential drop (DCPD), Clip gage and Strain gage; (4) data acquisition system. The cyclic pressure range used in the fatigue tests was 78 to 780 psig (72%SMYS) with R=0.1, which was based on historical operational pressure data and the Rain flow analysis. A constant frequency of 0.0526 Hz was selected for the testing to ensure the frequency requirement for corrosion fatigue is met. The remaining fatigue life of cracks-in-dents and failure modes were evaluated using the full-scale fatigue test results. Further, fatigue crack growth rates were established. Finally, a framework was developed for the life prediction of cracks in shallow dents based on the findings from six full-scale fatigue cyclic tests. This framework will assist liquid pipeline operators to estimate the remaining fatigue life for cracks in shallow dents utilizing inputs from ILI and pipeline's historical operational pressure fluctuation data and to mitigate the threat of cracks in dents in a timely manner. There is a related webinar.
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Koven, William, Gordon Grau, Benny Ron, and Tetsuya Hirano. Improving fry quality, survival and growth in commercially farmed fish by dietary stimulation of thyroid hormone production in premetamorphosing larvae. United States Department of Agriculture, 2004. http://dx.doi.org/10.32747/2004.7695856.bard.
Full textAbstract:
There is a direct correlation between successful metamorphosis from larvae to post-larvae and the quality of the resultant juveniles or fry. Juvenile quality, in turn, is a major factor influencing fish production level and market price. However, following the profound morphological and physiological changes occurring during metamorphosis, the emerging juveniles in some species characteristically demonstrate heterotrophic growth, poor pigmentation, cannibalism and generally poor survival. The white grouper (Epinephelus aeneus) in Israel and the Pacific threadfin (Polydactylussexfilis) in Hawaii are two promising candidates for mariculture that have high market value but a natural fishery that has sharply declined in recent years. Unfortunately, their potential for culture is severely hampered by variable metamorphic success limiting their production. The main objective was to compare the efficacy and economic viability of dietary or environmental iodine on metamorphic success and juvenile quality in the white grouper and the pink snapper which would lead to improved commercial rearing protocols and increased production of these species both in Israel and the US. The Hawaii Institute of Marine Biology encountered problems with the availability of pink snapper brood stock and larvae and changed to Pacific threadfin or moi which is rapidly becoming a premier aquaculture species in Hawaii and throughout the Indo-Pacific. The white grouper brood stock at the National Center for Mariculture was lost as a result of a viral outbreak following the sudden breakdown of the ozone purification system. In addition, the NCM suffered a devastating fire in the fall of 2007 that completely destroyed the hatchery and laboratory facilities although the BARD project samples were saved. Nevertheless, by studying alternate species a number of valuable findings and conclusions that can contribute to improved metamorphosis in commercially valuable marine species resulted from this collaborative effort. The Israeli group found that exposing white grouper larvae to external TH levels synchronized and increased the rate of metamorphosis. This suggested that sub-optimal synthesis of TH may be a major factor causing size heterogeneity in the larval population and high mortality through cannibalism by their larger more metamorphosed cohorts. Two protocols were developed to enrich the larvae with higher levels of the TH precursor, iodine; feeding iodine enriched Artemia or increasing the level of seawater iodine the larvae are exposed to. Results of accumulated iodine in gilthead seabream larvae indicated that the absorption of iodine from the water is markedly more efficient than feeding iodine enriched Artemia nauplii. Samples for TH, which will be analyzed shortly, will be able to determine if another dietary factor is lacking to effectively utilize surplus tissue iodine for TH synthesis. Moreover, these samples will also clarify which approach to enriching larvae with iodine, through the live food or exposure to iodine enriched seawater is the most efficient and cost effective. The American group found that moi larvae reared in ocean water, which possessed substantially higher iodine levels than those found in seawater well water, grew significantly larger, and showed increased survival compared with well water reared larvae. Larvae reared in ocean water also progressed more rapidly through developmental stages than those in low-iodine well seawater. In collaboration with Israeli counterparts, a highly specific and precise radioimmunoassay procedure for thyroid hormones and cortisol was developed. Taken altogether, the combined Hawaiian and Israeli collaborative research suggests that for teleost species of commercial value, adequate levels of environmental iodine are more determinate in metamorphosis than iodine levels in the live zooplankton food provided to the larvae. Insuring sufficiently high enough iodine in the ambient seawater offers a much more economical solution to improved metamorphosis than enriching the live food with costly liposomes incorporating iodine rich oils.