Literatura académica sobre el tema "FEM non lineare"
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Artículos de revistas sobre el tema "FEM non lineare"
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Tecusan, Remus y Konrad Zilch. "Sicherheitsaspekte bei nicht-linearen FEM Berechnungen/Safety aspects in non-linear FEM calculations". Bauingenieur 92, n.º 12 (2017): 518–27. http://dx.doi.org/10.37544/0005-6650-2017-12-34.
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Das semiprobabilistische Sicherheitskonzept mit Teilsicherheitsbeiwerten, welches der Nachweisführung in den aktuell gültigen Normen zu Grunde liegt, ist für lineare Schnittgrößenermittlung und Querschnittsbemessung gut geeignet. Bei nicht-linearen Finite-Elemente-Berechnungen lässt sich das wirkliche Tragverhalten eines konkreten Bauwerks oder Versuchs mit Materialparameter auf Mittelwertniveau am realistischsten simulieren. Deshalb ist es noch unklar, ob sich das Sicherheitskonzept mit Teilsicherheitsbeiwerten ohne Weiteres auf nicht-lineare Finite-Elemente-Berechnungen übertragen lässt. Durch den Einsatz von Bemessungswerten für Materialparameter in einer nicht-linearen Finite-Elemente-Berechnungen kann das Tragverhalten (Rissbildung, Umlagerungseffekte) eines Bauwerks oder Bauteils nicht wirklichkeitsnah abgebildet werden. Für nicht-lineare Finite-Elemente-Berechnungen gibt es eine Reihe von Sicherheitskonzepten, die mehr oder minder hohe Sicherheitsniveaus aufweisen. Dabei spielen die Eingangswerte einer nicht-linearen Finite-Elemente-Berechnung eine wesentliche Rolle für das erzielte Bemessungsniveau. Dazu muss noch beachtet werden, dass bei den angewendeten Sicherheitskonzepten alle Unsicherheiten durch entsprechende Sicherheitsfaktoren erfasst und abgedeckt werden.
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Annasiwaththa, Buddhika y Koichi Oka. "B206 Initial design and FEM analysis of a non-contact power transfer method for magnetically levitated linear slider". Proceedings of the Symposium on the Motion and Vibration Control 2015.14 (2015): 297–301. http://dx.doi.org/10.1299/jsmemovic.2015.14.297.
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Sin, F. S., D. Schroeder y J. Barbič. "Vega: Non-Linear FEM Deformable Object Simulator". Computer Graphics Forum 32, n.º 1 (23 de noviembre de 2012): 36–48. http://dx.doi.org/10.1111/j.1467-8659.2012.03230.x.
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Alotto, P., A. Castagnini, P. Girdinio y M. Nervi. "Adaptive FEM in 3D non‐linear magnetostatics". COMPEL - The international journal for computation and mathematics in electrical and electronic engineering 19, n.º 1 (marzo de 2000): 39–48. http://dx.doi.org/10.1108/03321640010302780.
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Kim, Jung-Ho, Chi-Joong Kim, Cheon-Seok Cha y Ji-Hoon Kim. "Recalculation Research of Material properties for CFRP FEM Non-linear Analysis". Journal of manufacturing engineering & technology 21, n.º 4 (15 de agosto de 2012): 608–12. http://dx.doi.org/10.7735/ksmte.2012.21.4.608.
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Chekhov, V. V. "Tensor-based matrices in geometrically non-linear FEM". International Journal for Numerical Methods in Engineering 63, n.º 15 (2005): 2086–101. http://dx.doi.org/10.1002/nme.1343.
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Honda, Riki, Hisakazu Sakai y Sumio Sawada. "Non-iterative time integration scheme for non-linear dynamic FEM analysis". Earthquake Engineering & Structural Dynamics 33, n.º 1 (19 de diciembre de 2003): 111–32. http://dx.doi.org/10.1002/eqe.341.
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NAGAI, Gakuji y Hideki GOTOH. "Non-linear Elastic Constitutive Law for Magneto-strictive FEM". Proceedings of The Computational Mechanics Conference 2014.27 (2014): 407–8. http://dx.doi.org/10.1299/jsmecmd.2014.27.407.
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Pecník, Miroslav, Viktor Borzovič y Kamil Laco. "Non-Linear FEM Analysis of Integral Bridges Transition Area". Solid State Phenomena 259 (mayo de 2017): 152–57. http://dx.doi.org/10.4028/www.scientific.net/ssp.259.152.
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The transition area of bridges is non-homogeneous solid, which consists of soil embankment, transition slab and roadway layers. These transition area elements consist of various materials with different properties. Besides the imposed loads, behavior of these areas is significantly affected by uneven settlement between the bridge abutment and soil embankment. In case of integral bridges horizontal movements of a bridge caused mostly by temperature and ongoing rheological phenomena in concrete have to be taken into account. This leads to abutment deformation in combination with time dependent soil consolidation it results in varying earth pressure over the bridges lifetime together with cyclic horizontal movements of the pavement resulting in its cracks and excessive deformations. In this paper, comparison of different approaches to finite element analysis of transition areas is presented. First analysis was performed using area elements to represent the bridge structure, and volume elements to represent embankment, while second analysis was performed in more conservative way using spring based method proposed by Křížek[3], as representation of the surrounding soil. Results obtained via both methods are compared with each other as well as with data obtained from experimental measurment of a transition area conducted in Switzerland [1].
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De Luca, V. y A. Della Chiesa. "A Creep Non-Linear FEM Analysis of Glulam Timber". Mechanics of Advanced Materials and Structures 20, n.º 6 (junio de 2013): 489–96. http://dx.doi.org/10.1080/15376494.2011.627643.
Texto completoTesis sobre el tema "FEM non lineare"
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Ulfberg, Adrian. "Probabilistic non-linear finite element analysis of concrete buttress dams". Thesis, Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, 2019. http://urn.kb.se/resolve?urn=urn:nbn:se:ltu:diva-72701.
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Assessment of concrete buttress dams today consists of using analytical methods to investigate the stability in different failure modes. However, they simplify the problem at hand and neglect certain important features linked to geometry and thus not truthfully appraise the structures real stability. This could be economically costly in assessments of both existing dam structures as this would eventually lead to unwarranted rehabilitation. The same can be said for dams under design. Kalhovd dam is a concrete buttress dam that has recently undergone assessment where certain sections proved unstable in either failure mode. This study focused specifically on a buttress, numbered 49, of said dam which was deemed in the assessment to be unstable in the overturning and sliding failure mode. The methodology used was to assess and compare stability for different methods of calculation, meaning analytical versus numerical analysis. The numerical analysis was performed with two-dimensional finite element analyses in a commercial FEM-software called ATENA which focuses on reinforced concrete structures. The numerical models made, were then probabilistically analysed by randomizing various material parameters to see their effect on stability. Some FEA models discarded the conventional way of modelling loads, as required by standards, to more realistically portray load actions on dams based on historical measurement. Results from this study showed dissimilarity of stability for buttress 49 depending on which method of analysis was performed. Analytical methods proved to yield the most conservative results and concluded the structure unsafe, while including an accurate representation of the geometry in FEA models improved the stability such that it can be considered stable against load actions stated in guidelines. Furthermore, material parameters randomized in the probabilistic analysis substantiated that various concrete variables had relatively little effect on structural overall strength in the most common failure modes.
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Marchionni, Elianires. "Valutazione del rischio sismico di un edificio strategico destinato a sede della di.coma.c di Parma". Master's thesis, Alma Mater Studiorum - Università di Bologna, 2021.
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Una delle principali prerogative nell’ambito della protezione civile è lo studio e l’analisi del rischio sismico. Non è possibile prevedere tali eventi né tanto meno evitare che si verifichino, tutto ciò che si può fare e garantire una sicurezza adeguata e ridurre considerevolmente il fattore di rischio.
La pianificazione dell’emergenza rappresenta una delle strategie principali per mitigare gli effetti di un evento sismico.
Il seguente lavoro svolge un analisi in ambito lineare dinamico e in ambito statico non lineare valutando le zone di criticità e gli indici di rischio sismico di un edificio intelaiato in c.a.
la modellazione dell'edificio ha previsto un analisi storico-critica dell'opera al fine di garantire un fattore di confidenza ed un livello di dettaglio tali da permettere un riscontro significativo sulle valutazioni desunte. L’edificio è stato progettato utilizzando come normativa di riferimento il Decreto del Ministro dei lavori Pubblici 16 gennaio 1996 “Norme tecniche per le costruzioni in zone sismiche”, assumendo come parametri di progetto un grado di sismicità S = 9 e un coefficiente di protezione sismica I = 1.4 (valido per le opere la cui resistenza al sisma è di importanza primaria per le necessità della protezione civile). Come precedentemente anticipato, l’edificio è già stato analizzato e sviluppato con un modello agli elementi finiti, la sua capacità sismica è stata valutata in ambito elastico lineare tramite un’analisi modale con spettro di risposta sia normativo proposto dalle NTC2008 che con spettro di risposta sismico locale realizzato ad hoc per l’edificio.
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Teklemariam, Daniel Mekonnen y Bennie Hamunzala. "Design of Thick Concrete Beams : Using Non-Linear FEM". Thesis, KTH, Bro- och stålbyggnad, 2016. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-189141.
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The experimental studies performed on the behaviour of very thick concrete beams subjected to static loads have revealed that the shear mechanisms play an important role in the overall response and failure behaviour. The aim of this thesis is to recommend suitable design methods for thick concrete beams subjected to off-centre static concentrated load according Eurocode 2 by using non-linear finite element analysis (NLFEA). To achieve this task, Abaqus/Explicit has been used by employing constitutive material models to capture the material non-linearity and stiffness degradation of concrete. Concrete damaged plasticity model and perfect plasticity model has been used for concrete and steel respectively. Three dilation angles (30º, 38º and 45º) and fracture energy from FIB 1990 (76 N/m) and FIB 2010 (142 N/m) has been used to investigate their influence on the finite element model. The dilation angle of 38º and FIB 2010 fracture energy was adopted as the suitable choice that reasonably matched with the experimental results. In verifying and calibrating the finite element model, the experimental results of the thick reinforced concrete beam conducted by the American Concrete Institute have been used. Three design approaches in the ultimate and serviceability limit state according to Eurocode 2 recommendations have been used namely; the beam method, strut and tie method and shell element method. Using the reinforcement detailing of the hand calculations of beam method and strut and tie method and linear finite element analysis of shell element method, non-linear finite element models have been pre-processed and analysed in Abaqus/Explicit. During the post-processing, the results have been interpreted and compared between the three design methods. The results under consideration are hand-calculated load at 0.3 mm crack width, FE-load at 0.3 mm crack width, amount of reinforcement and FE-failure load. The comparison of the results between the three design approaches (beam method, strut and tie method and shell element method) indicates that strut and tie method is better design approach, because it is relatively economic with regards to the quantity of reinforcement bars, has the higher load capacity and has a higher load at crack width of 0.3 mm crack width.De experimentella studier som utförts på tjocka betongbalkar som utsätts för statisk last har visat att skjuvning spelar en viktig roll i brottmekanismen. Syftet med detta examensarbete är att rekommendera lämpliga dimensioneringsmetoder för tjock betongbalkar utsatt for statisk koncentrerad last enligt Eurokod 2 med hjälp av ickelinjära finita element metod. Abaqus/Explicit användes genom att utnyttja konstitutiva materialmodeller för att fånga materialens icke-linjäritet och minskad styvhet. Tre dilatationsvinklar (30°, 38° och 45°) och två brottenergi från FIB 1990 (76 N/m) och FIB 2010 (142 N/m) tillämpas för att kontrollera deras inverkan på FE-modellerna. Dilatationsvinkel med 38° och FIB 2010 med högre brottenergi valdes i de icke-linjära finita elementanalyserna. Kontroll av FE-modellerna är baserad på ”American Concret Institutes” experimentella resultat på de tjocka betongbalkarna. Handberäkningar av tjocka betongbalkar har utförts i brott- och bruksgränstillstånd med tre dimensioneringsmetoder i Eurokod 2 nämligen balk metoden, fackverksmetoden och linjära-FE skalelementmetoden. Jämförelse har gjorts för de olika dimensioneringsmetoderna, genom att använda de armeringsdetaljer av handberäkningar i de verifierade och kalibrerade icke linjära FE-modellerna i Abaqus/Explicit. Resultaten i fråga är last för 0.3 mm handberäknad sprikvidd, FE-last för 0.3 mm sprikvidd, armeringsmängd och FE-brottlast. Jämförelse av resultaten mellan de tre dimensioneringsmetoder (balkmetod, fackverksmetod och skalelementmetod) visar att fackverksmetod är bättre design metod, eftersom det är relativt ekonomiskt med avseende på armeringsmängd, har högre lastkapacitet och last på 0.3 mm sprickvidd.
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Glänzel, Janine. "Kurzvorstellung der 3D-FEM Software SPC-PM3AdH-XX". Universitätsbibliothek Chemnitz, 2009. http://nbn-resolving.de/urn:nbn:de:bsz:ch1-200900211.
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In diesem Preprint wird die Weiterentwicklung der 3D-FEM Software SPC-PM3Adh-XX kurz vorgestellt. Die Einleitung beschreibt schematisch den Ablauf des Programms und sechs Programmversionen. Weiterhin werden die allgemeinen Bedienungsanleitungen und die Funktionalität der einzelnen Versionen aufgeführt. Im letzten Abschnitt, dem Anhang, werden kurz das Standardfile und das Radiale Basisfunktionen-Datenfile erklärt.
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Teich, Martin. "Non-linear THz spectroscopy in semiconductor quantum structures". Doctoral thesis, Saechsische Landesbibliothek- Staats- und Universitaetsbibliothek Dresden, 2014. http://nbn-resolving.de/urn:nbn:de:bsz:14-qucosa-154595.
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In this thesis the strong coupling of excitons with intense THz radiation in GaAs/AlGaAs and InGaAs/GaAs multi-quantum wells (MQW) and the strong coupling of electrons to phonons in InAs/GaAs quantum dots (QD) are investigated. Experimental studies in the field of non-linear terahertz (THz) spectroscopy were carried out using the narrowband THz emission of a free-electron laser (FEL). In the first part intra-excitonic transitions are pumped with intense THz radiation.
The THz-pump–near-infrared(NIR)-probe experiments are analysed focusing on the behaviour of the Autler-Townes (AT) splittings with increasing THz field strength. Furthermore measurements of the temperature dependence up to room temperature are discussed. With the help of a microscopic theory the contribution of higher lying intra-excitonic states to the lineshape and splitting of the heavy-hole absorption line is analysed at low temperatures. The second part is about the lifetime and dephasing time of polarons in InAs/GaAs QDs that was measured for inter-sublevel excitation in the THz spectral region (below the Reststrahlen band). Single electrons inside QDs strongly interact with phonons and form quasi-particles called polarons. The temperature dependence of the dephasing behavior and the contribution of pure dephasing is discussed.
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Lee, Chun Hung. "Non-Linear Contact Analysis of Meshing Gears". DigitalCommons@CalPoly, 2009. https://digitalcommons.calpoly.edu/theses/236.
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Gear transmission systems are considered one of the critical aspects of vibration analysis, and it contains various potential faults such as misalignment, cracks, and noise. Therefore, it requires vibration monitoring to ensure the system is operating properly. Case mounted accelerometers are frequently used to monitor frequencies in a system. However, it is not a simple task to identify and interpret the acceleration data since there are many gear mesh frequencies present. One of the approaches utilized by researchers to perform gear diagnostic is Finite Element Modeling. This study focuses on stiffness cycle and meshing stiffness of non-linear quasi-static finite element modeling. The comparisons of meshing stiffness will concentrate on the type of elements, the integration methods, the meshing quality, plane stress and plane strain analysis, sensitivity of model tolerance, and crack modeling. The results show that the FEA approach is extremely sensitive to tolerance, mesh density, and element choice. Also, the results indicate that a complete sensitivity and convergence studies should be carried out for a satisfactory stiffness match.
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Zhou, Zhengming. "Non-linear elastic modelling of coupled deformation, heat, air and moisture transfer in unsaturated soil". Thesis, Cardiff University, 1996. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.360637.
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Pablos, Rabano Alejandro. "Modeling of a PMSynRel stator with concentrated windings using FEM and non-linear reluctance networks". Thesis, KTH, Elektrisk energiomvandling, 2013. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-124543.
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Permanent magnets synchronous reluctance (PMSynRel) motors are attractive due to their high torque density and because a lower quantity of permanent magnets is necessary in comparison with other permanent magnet machines. This thesis deals with the analysis of PMSynRel machines using a finite element method (FEM) and reluctance networks. First, a PMSynRel machine model is built in order to carry out simulations using a finite element method package. The effect of different design parameters such as the combination of the number of poles and slots, the number of flux barriers or the number of magnets can be studied since the implementation provides the possibility to change those variables. Next, a reluctance networks model, aimed to enable lower computation times than corresponding finite element models, is implemented for analysing the flux density distributions along the air gap of the machine disregarding the magnetic influence of the rotor. Finally, the results are compared with FEM simulations. It is concluded that the agreement reached is satisfactory in most of the cases analysed.
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Dichev, Kiril. "Performanceanalyse und -optimierung der Gleichungslösung eines bestehenden Strukturmechanik-FEM-Programms für den Tunnelbau". Stuttgart : Universitätsbibliothek der Universität Stuttgart, 2006. http://nbn-resolving.de/urn:nbn:de:bsz:93-opus-27002.
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Polidori, Andrea. "Analisi numerica non lineare di un nodo trave colonna in conglomerato cementizio". Master's thesis, Alma Mater Studiorum - Università di Bologna, 2011. http://amslaurea.unibo.it/2623/.
Texto completoLibros sobre el tema "FEM non lineare"
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Yamin, Dang y Zhang Chuanyin, eds. Fei xian xing da di ce liang xin hao xiao bo fen xi li lun yu fang fa: Wavelet analysis theories and methods for non-linear geodetic signals. Beijing Shi: Ce hui chu ban she, 2011.
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Philippe, Blanchard, Dias J. P. 1944- y Stubbe J. 1959-, eds. New methods and results in non-linear field equations: Proceedings of a conference held at the University of Bielefeld, Fed. Rep. of Germany, 7-10 July 1987. Berlin: Springer-Verlag, 1989.
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Dias, J. P. y Philippe Blanchard. New Methods and Results in Non-Linear Field Equations: Proc of a Conference Held at the University of Bielefeld, Fed. Rep. of Germany, 7-10 July 198 (Lecture Notes in Physics). Springer, 1990.
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Walker, James C. G. Numerical Adventures with Geochemical Cycles. Oxford University Press, 1991. http://dx.doi.org/10.1093/oso/9780195045208.001.0001.
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The dynamic, evolving Earth, and the mathematical representation of its geochemical changes are the subject of this timely, helpful handbook. Global warming, changes in the ocean, and the effects of fossil fuel combustion are just a few of the phenomena that make the development of geochemical models critical. But what computational methods will help to accurately carry out this task? This new text teaches the methodology of computational simulation of environmental change. The author presents interesting applications of his methods to describe the response of the ocean and atmosphere to the infusion of pollutants, the effect of evaporation on seawater composition, climate change, and many other aspects of the Earth's evolving ecosystem. He also presents simple approaches for solving non-linear systems, calculating isotope ratios, and dealing with chains of identical reservoirs. With creative programs that can be executed on any personal computer, Walker offers earth scientists the techniques necessary to address the key problems in their field.
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Drach, Alexis y Youssef Cassis, eds. Financial Deregulation. Oxford University Press, 2021. http://dx.doi.org/10.1093/oso/9780198856955.001.0001.
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A wave of liberalization swept the end of the twentieth century. From the 1970s and 1980s onwards, most developed countries have passed various measures to liberalize and ‘modernize’ the financial markets. Each country had its agenda, but most of them have experienced, to a different extent, a change in regulatory regime. This change, often labelled deregulation and associated with the advent of neoliberalism, was sharply contrasting with the previous era, the Bretton Woods system, which has sometimes been portrayed as an era of ‘financial repression’. On the other hand, a quick glance at financial regulation today, at the amount of paper it produces, at its complexity, at the number of people involved, and at the resources invested in it, is enough to say that, somehow, there is more regulation today than ever before. In the new system, financial regulation has taken unprecedented importance. As more archival material is becoming available, a better understanding of the fundamental changes in the regulatory environment towards the end of the twentieth century is now possible. What kind of change exactly was deregulation? Did competition between financial regulators lead to a ‘race to the bottom’ in regulation? Is deregulation responsible for the recurring financial crises which seem to have characterized the international financial system since the 1980s? The movement towards a more liberal regulatory regime was neither linear nor simple. This book—a collection of chapters studying deregulation in various countries and contexts—examines the national and international pathways of deregulation by providing an in-depth analysis of a short but crucial period in a few major countries.
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Pritchett, Lant, Kunal Sen y Eric Werker, eds. Deals and Development. Oxford University Press, 2017. http://dx.doi.org/10.1093/oso/9780198801641.001.0001.
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When are developing countries able to initiate periods of rapid growth and why have so few of these countries been able to sustain growth over decades? Deals and Development: The Political Dynamics of Growth Episodes seeks to answer these questions and many more through a novel conceptual framework built from a political economy of business–government relations. Economic growth for most developing countries is not a linear process. Growth instead proceeds in booms and busts, yet most frameworks for thinking about economic growth are built on the faulty assumption that a country’s economic performance is largely stable. Deals and Development explains how growth episodes emerge and when growth, once ignited, is maintained for a sustained period. It applies its new framework to examining the growth of countries across a range of institutional and political contexts in Africa and Asia, using the examples of Bangladesh, Cambodia, India, Malaysia, Thailand, Ghana, Liberia, Malawi, Rwanda, and Uganda. Through these country analyses it demonstrates the explanatory power of its framework and the importance of feedback cycles in which economic trends interact with political behaviour to either sustain or terminate a growth episode. Offering a lens through which to analyse complex scenarios and unwieldy amounts of information, this book provides actionable levers of intervention to bring around reform and improve a country’s chance at achieving transformative economic growth.
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Tibaldi, Stefano y Franco Molteni. Atmospheric Blocking in Observation and Models. Oxford University Press, 2018. http://dx.doi.org/10.1093/acrefore/9780190228620.013.611.
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The atmospheric circulation in the mid-latitudes of both hemispheres is usually dominated by westerly winds and by planetary-scale and shorter-scale synoptic waves, moving mostly from west to east. A remarkable and frequent exception to this “usual” behavior is atmospheric blocking. Blocking occurs when the usual zonal flow is hindered by the establishment of a large-amplitude, quasi-stationary, high-pressure meridional circulation structure which “blocks” the flow of the westerlies and the progression of the atmospheric waves and disturbances embedded in them. Such blocking structures can have lifetimes varying from a few days to several weeks in the most extreme cases. Their presence can strongly affect the weather of large portions of the mid-latitudes, leading to the establishment of anomalous meteorological conditions. These can take the form of strong precipitation episodes or persistent anticyclonic regimes, leading in turn to floods, extreme cold spells, heat waves, or short-lived droughts. Even air quality can be strongly influenced by the establishment of atmospheric blocking, with episodes of high concentrations of low-level ozone in summer and of particulate matter and other air pollutants in winter, particularly in highly populated urban areas.Atmospheric blocking has the tendency to occur more often in winter and in certain longitudinal quadrants, notably the Euro-Atlantic and the Pacific sectors of the Northern Hemisphere. In the Southern Hemisphere, blocking episodes are generally less frequent, and the longitudinal localization is less pronounced than in the Northern Hemisphere.Blocking has aroused the interest of atmospheric scientists since the middle of the last century, with the pioneering observational works of Berggren, Bolin, Rossby, and Rex, and has become the subject of innumerable observational and theoretical studies. The purpose of such studies was originally to find a commonly accepted structural and phenomenological definition of atmospheric blocking. The investigations went on to study blocking climatology in terms of the geographical distribution of its frequency of occurrence and the associated seasonal and inter-annual variability. Well into the second half of the 20th century, a large number of theoretical dynamic works on blocking formation and maintenance started appearing in the literature. Such theoretical studies explored a wide range of possible dynamic mechanisms, including large-amplitude planetary-scale wave dynamics, including Rossby wave breaking, multiple equilibria circulation regimes, large-scale forcing of anticyclones by synoptic-scale eddies, finite-amplitude non-linear instability theory, and influence of sea surface temperature anomalies, to name but a few. However, to date no unique theoretical model of atmospheric blocking has been formulated that can account for all of its observational characteristics.When numerical, global short- and medium-range weather predictions started being produced operationally, and with the establishment, in the late 1970s and early 1980s, of the European Centre for Medium-Range Weather Forecasts, it quickly became of relevance to assess the capability of numerical models to predict blocking with the correct space-time characteristics (e.g., location, time of onset, life span, and decay). Early studies showed that models had difficulties in correctly representing blocking as well as in connection with their large systematic (mean) errors.Despite enormous improvements in the ability of numerical models to represent atmospheric dynamics, blocking remains a challenge for global weather prediction and climate simulation models. Such modeling deficiencies have negative consequences not only for our ability to represent the observed climate but also for the possibility of producing high-quality seasonal-to-decadal predictions. For such predictions, representing the correct space-time statistics of blocking occurrence is, especially for certain geographical areas, extremely important.
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Frew, Anthony. Air pollution. Editado por Patrick Davey y David Sprigings. Oxford University Press, 2018. http://dx.doi.org/10.1093/med/9780199568741.003.0341.
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Any public debate about air pollution starts with the premise that air pollution cannot be good for you, so we should have less of it. However, it is much more difficult to determine how much is dangerous, and even more difficult to decide how much we are willing to pay for improvements in measured air pollution. Recent UK estimates suggest that fine particulate pollution causes about 6500 deaths per year, although it is not clear how many years of life are lost as a result. Some deaths may just be brought forward by a few days or weeks, while others may be truly premature. Globally, household pollution from cooking fuels may cause up to two million premature deaths per year in the developing world. The hazards of black smoke air pollution have been known since antiquity. The first descriptions of deaths caused by air pollution are those recorded after the eruption of Vesuvius in ad 79. In modern times, the infamous smogs of the early twentieth century in Belgium and London were clearly shown to trigger deaths in people with chronic bronchitis and heart disease. In mechanistic terms, black smoke and sulphur dioxide generated from industrial processes and domestic coal burning cause airway inflammation, exacerbation of chronic bronchitis, and consequent heart failure. Epidemiological analysis has confirmed that the deaths included both those who were likely to have died soon anyway and those who might well have survived for months or years if the pollution event had not occurred. Clean air legislation has dramatically reduced the levels of these traditional pollutants in the West, although these pollutants are still important in China, and smoke from solid cooking fuel continues to take a heavy toll amongst women in less developed parts of the world. New forms of air pollution have emerged, principally due to the increase in motor vehicle traffic since the 1950s. The combination of fine particulates and ground-level ozone causes ‘summer smogs’ which intensify over cities during summer periods of high barometric pressure. In Los Angeles and Mexico City, ozone concentrations commonly reach levels which are associated with adverse respiratory effects in normal and asthmatic subjects. Ozone directly affects the airways, causing reduced inspiratory capacity. This effect is more marked in patients with asthma and is clinically important, since epidemiological studies have found linear associations between ozone concentrations and admission rates for asthma and related respiratory diseases. Ozone induces an acute neutrophilic inflammatory response in both human and animal airways, together with release of chemokines (e.g. interleukin 8 and growth-related oncogene-alpha). Nitrogen oxides have less direct effect on human airways, but they increase the response to allergen challenge in patients with atopic asthma. Nitrogen oxide exposure also increases the risk of becoming ill after exposure to influenza. Alveolar macrophages are less able to inactivate influenza viruses and this leads to an increased probability of infection after experimental exposure to influenza. In the last two decades, major concerns have been raised about the effects of fine particulates. An association between fine particulate levels and cardiovascular and respiratory mortality and morbidity was first reported in 1993 and has since been confirmed in several other countries. Globally, about 90% of airborne particles are formed naturally, from sea spray, dust storms, volcanoes, and burning grass and forests. Human activity accounts for about 10% of aerosols (in terms of mass). This comes from transport, power stations, and various industrial processes. Diesel exhaust is the principal source of fine particulate pollution in Europe, while sea spray is the principal source in California, and agricultural activity is a major contributor in inland areas of the US. Dust storms are important sources in the Sahara, the Middle East, and parts of China. The mechanism of adverse health effects remains unclear but, unlike the case for ozone and nitrogen oxides, there is no safe threshold for the health effects of particulates. Since the 1990s, tax measures aimed at reducing greenhouse gas emissions have led to a rapid rise in the proportion of new cars with diesel engines. In the UK, this rose from 4% in 1990 to one-third of new cars in 2004 while, in France, over half of new vehicles have diesel engines. Diesel exhaust particles may increase the risk of sensitization to airborne allergens and cause airways inflammation both in vitro and in vivo. Extensive epidemiological work has confirmed that there is an association between increased exposure to environmental fine particulates and death from cardiovascular causes. Various mechanisms have been proposed: cardiac rhythm disturbance seems the most likely at present. It has also been proposed that high numbers of ultrafine particles may cause alveolar inflammation which then exacerbates preexisting cardiac and pulmonary disease. In support of this hypothesis, the metal content of ultrafine particles induces oxidative stress when alveolar macrophages are exposed to particles in vitro. While this is a plausible mechanism, in epidemiological studies it is difficult to separate the effects of ultrafine particles from those of other traffic-related pollutants.
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Marques, Marcia Alessandra Arantes, ed. Estudos Avançados em Ciências Agrárias. Bookerfield Editora, 2022. http://dx.doi.org/10.53268/bkf22040700.
Texto completoResumen
Esta obra tem por objetivo apresentar produções acadêmicas que possuem em comum a grande área Ciências Agrárias. Permeando por este vasto tema, nas próximas páginas serão apresentados trabalhos que abordam sobre Ciência e Tecnologia de Alimentos, Engenharia Agrícola, bem como na Ciência Animal. Desta forma, para melhor direcionar o fluxo da leitura, o livro está dividido em capítulos, nos quais os primeiros apresentados abordam o tema “Ciência e Tecnologia em Alimentos” e apresenta trabalhos desenvolvidos com ênfase em controle de qualidade, aproveitamento de subprodutos e planejamento experimental. Acredito que o controle de qualidade de alimentos e o aproveitamento de subprodutos são temas de grande relevância para nosso país e desta forma, nós como professores e pesquisadores, devemos, por meio da ciência sempre trazer novas pesquisas a fim de preencher lacunas no conhecimento e apresentar novas possibilidades e soluções para o melhor aproveitamento e utilização dos alimentos. Na sequência, são apresentados trabalhos desenvolvidos na temática de produção e caracterização de forrageiras de cereais de inverno, predição da produtividade da cultura da soja por meio da aplicação de modelos de regressão linear, bem como relatar um estudo casos de onfalite em bezerros. Neste sentido, os trabalhos aqui apresentados, alinham-se a estas demandas e trazem novas analises que condizem com as necessidades emergentes da nossa sociedade. Profª. Drª. Heloisa Gabriel Falcão. Instituto Federal de Educação (IFG) – Campus Inhumas O crescimento da economia e da taxa de urbanização de alguns países, especialmente da Ásia, resultou em significativas mudanças no estilo de vida das populações neles residentes, com incrementos no consumo de bens duráveis, energia e alimentos. Além disso, estima-se que a população mundial ultrapassará 8,5 bilhões de pessoas até 2030 e que a maior porção desse crescimento demográfico ocorrerá na China, Índia e Indonésia. Esse contexto representa um desafio para a segurança alimentar e energética mundial, uma vez que, se as tendências atuais forem mantidas, a área agrícola deverá aumentar em cerca de 42 milhões hectares até 2027. Contudo, a limitação de terras agricultáveis permitirá um crescimento de apenas 10% em escala mundial, sendo que, quase metade disso se dará no Brasil e na Argentina. Assim, a América do Sul será a mais importante fonte de expansão agrícola do mundo. Com abundantes recursos naturais e grande potencial de desenvolvimento agropecuário, a América do Sul configura importante elemento estratégico para melhorar a segurança alimentar global. Em particular, o setor agropecuário brasileiro é reconhecido internacionalmente pela elevada inserção no mercado globalizado, com destaque para produção de carne de frango, açúcar, suco de laranja, fumo, café e soja... produtos do agronegócio brasileiro que são campeões no ranking de exportações do mercado global. Outros produtos agropecuários brasileiros que merecem grande destaque por configurarem entre as primeiras posições no ranking mundial de produção e exportação são: carne bovina, óleo de soja, farelo de soja, milho e leite bovino. A pandemia de Covid-19 impactou negativamente a economia mundial em razão das necessidades sanitárias e de distanciamento social. Ainda assim, mesmo em momentos de maiores restrições de circulação e transportes, vários segmentos agropecuários do Brasil experimentaram expressiva elevação na produção e vendas nacionais e internacionais. Isso ocorreu em razão das políticas preventivas de vários países no sentido de garantir a segurança alimentar de suas populações, restringindo as exportações e aumentando as importações de alimentos para ampliar suas reservas estratégicas. Essas políticas preventivas não foram adotadas pelo Brasil e, devido ao desmonte dos estoques reguladores e da redução substancial dos recursos destinados a agricultura familiar desde 2017, o mercado interno foi drasticamente afetado pelas exportações record de 2020 e 2021. A redução da quantidade de milho, soja e carnes, principalmente bovina, no mercado interno promoveu expressivo aumento dos preços num momento onde houve aumento de desemprego e queda de renda das classes menos abastadas da população brasileira. O Brasil, que já tinha voltado ao mapa da fome em 2018, sofreu um aumento de 14% no número de domicílios com algum tipo de insegurança alimentar entre 2018 e 2020. Estima-se que mais de 55% da população brasileira sofreu de insegurança alimentar entre 2020 e 2021, conforme dados da rede Penssan e da Organização das Nações Unidas. Nesse contexto, apesar das reduções dramáticas no volume de recursos públicos destinados a produção cientifica no Brasil, tornou-se ainda mais imprescindível a produção de pesquisas e a disseminação do conhecimento resultante delas. Composto por sete capítulos que apresentam pesquisas relevantes, esse livro pretende contribuir com subsídios significativos para o enfrentamento desse imenso desafio que se apresenta, ainda mais intenso nesses tempos de pós-Covid-19, que é elevar a eficiência da produção agropecuária a fim de garantir melhores condições de segurança alimentar para a população brasileira. O primeiro capítulo apresenta uma proposta de utilização da farinha de okara para o enriquecimento do hamburguer de carne bovina. Um dos produtos mais conhecidos do processamento da soja é o leite de soja ou extrato aquoso de soja. Ele é obtido a partir da lavagem, maceração, aquecimento e filtração dos grãos de soja. O okara é o subproduto solido do processo de filtração que separa o leite de soja. Aproximadamente, 250 g de farinha de okara são obtidos a partir do processamento de cada quilo de soja. Trata-se de um alimento altamente nutritivo, fonte de isoflavonas, antioxidantes, fibras solúveis e insolúveis que, além de auxiliar na redução de colesterol e triglicerídeos, previne a ação carcinogênica do bolo fecal. Os capítulos 2 e 3 apresentam um estudo que desenvolveu e avaliou as características químicas, físicas e funcionais de biscoitos, tipo cookie, com substituição parcial de farinha de trigo por farinha de gérmen de milho. Essa proposta se mostra extremamente relevante do ponto de vista econômico e nutricional. Uma vez que o advento do conflito bélico entre Rússia e Ucrânia tende a reduzir a oferta de trigo no mercado global e elevar seus preços. O Brasil é o segundo maior produtor de milho do planeta e apenas o 21º produtor de trigo. O resultado disso é que o Brasil importa cerca de 50% do trigo consumido no mercado interno. Além disso, o aumento da prevalência de pessoas com sensibilidade ao glúten, apontado pela pesquisa nacional de saúde do IBGE em 2017, torna esse tipo de experimento, muito relevante para o aumento de alternativas alimentares para esse público. O capítulo 4 compreende um estudo que identificou os agentes causadores de mastite em vacas leiteiras. Além disso, avaliou a relação entre a sua ocorrência de mastite e a qualidade do leite. A mastite é uma reação inflamatória da glândula mamária, geralmente associada à presença de microrganismos, que reduz a qualidade do leite e seus derivados, bem como a segurança do consumidor em razão de alterações na composição físico-química e sensorial dos produtos. Trata-se de uma pesquisa de grande relevância, uma vez que a retomada das exportações de leite para a China em 2021 tende a reduzir a oferta no mercado interno. Ainda sem as exportações para a China, o Brasil vendeu cerca de 29 milhões de toneladas de leite para Argélia, Venezuela, Estados Unidos, Argentina e Uruguai em 2021. Isso explica parte da pressão inflacionaria sobre o produto desde o início das medidas de contenção da Covid-19. Nesse contexto, contribuições que auxiliem na melhoria da qualidade e aumento da produtividade são salutares. O capitulo 5 nos relata um experimento que analisou as características químicas e bromatológicas de forragens de cereais de inverno em duas alturas de corte do solo e os benefícios da manutenção da cobertura vegetal na forma de matéria seca. Cereais de inverno, como centeio, trigo, triticale, cevada e aveia, além de produzirem grãos utilizados na alimentação humana, podem servir de alimento para aves, suínos, bovinos de corte, ovinos e, principalmente, vacas leiteiras. Na região Sul do Brasil, durante o inverno, não é incomum que grande parte de áreas agrícolas e máquinas fiquem ociosas. Dessa forma, a produção de cereais de inverno para forragear os rebanhos e para formar reservas para épocas de escassez parece ser uma estratégia viável para melhorar a constância da produtividade animal, gerando renda e diluindo os custos fixos da propriedade rural. Ademais, a manutenção de matéria seca no solo contribui para a redução de custos por meio da conservação da fertilidade do solo e redução da perda de carbono e necessidade de insumos. O sexto capítulo trata da utilização de técnicas de sensoriamento remoto para estimar a produtividade da cultura da soja, com a utilização de imagens de satélite. São apresentados modelos de regressão múltipla para prever a produtividade a partir de índices de vegetação (NDVI, SAVI, NDWI e EVI2). Ainda que pesquisas oficiais com as do IBGE e CONAB estimem a produtividade da soja com relativa precisão em escala estadual, elas são baseadas em abordagens qualitativas com grupos focais. Assim, o desenvolvimento de novas técnicas para o acompanhamento das culturas em escala microrregional pode contribuir para a redução de custos e maior precisão nas pesquisas oficiais. Além disso, os produtores e operadores do agronegócio podem fazer uso de insumos específicos para o planejamento da cultura e tomada de decisões. O capitulo 7, último desse livro, relata um estudo de 30 casos de onfalite em bezerros, dos quais 15 animais foram tratados conservadoramente e 15 submetidos ao tratamento cirúrgico. A onfalite constitui uma infecção dos remanescentes umbilicais cuja evolução pode resultar em óbito do animal ou comprometer o crescimento e rentabilidade do sistema produtivo desse. Os escassos estudos epidemiológicos brasileiros, a respeito dessa afecção umbilical, relatam que entre 21% e 45% dos bezerros neonatos desenvolverão algum nível dessa infecção e desses, entre 5,5% e 10% irão a óbito. Os resultados do estudo descrito nesse capítulo são extremamente relevantes para que criadores, zootecnistas e médicos veterinários tenham maios evidencias na tomada de decisão a respeito dos procedimentos a serem adotadas diante de tal situação. João Francisco Severo Santos. Doutor em Ciências do Ambiente – UFT. Analista de Pesquisas Agropecuárias - IBGE
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Jovic, Sebastián Miguel. Geología y metalogénesis de las mineralizaciones polimetálicas del área El Tranquilo (Cerro León), sector central del Macizo del Deseado, provincia de Santa Cruz. Editorial de la Universidad Nacional de La Plata (EDULP), 2010. http://dx.doi.org/10.35537/10915/4346.
Texto completoResumen
La presente investigación tiene como eje principal el estudio detallado de las mineralizaciones y la geología de un área del Macizo del Deseado con características geológicas y metalogénicas únicas. La elección del área del El Tranquilo o también conocido como “anticlinal” El Tranquilo, como zona de estudio, se ha basado en el reducido conocimiento y la presencia características atípicas en las mineralizaciones y la escasa representación, en el Macizo del Deseado, de las rocas y unidades geológicas aflorantes. La investigación ha sido realizada en tres etapas: una primera con recopilación de antecedentes y trabajo de campo, una segunda analítica con trabajos de laboratorio y una tercera etapa interpretativa. Se realizó el procesado de imágenes satelitales (TM, SPOT, IKONOS) y se ejecutaron mapeos geológico-estructurales de detalle y semidetalle (con elaboración de una cartografía digital), descripción de testigos de sondeos (gran parte de los 30.000 metros de las perforaciones ejecutadas en la propiedad minera), se realizaron estudios petrográficos, calcográficos, de rayos X, determinaciones geoquímicas, estudios de inclusiones fluidas, de microscopía electrónica, microsonda electrónica, determinaciones geocronológicas y análisis de isótopos estables e inestables. Además se participó de otros trabajos complementarios realizados durante las distintas etapas de exploración minera, tales como geoquímica de suelos, muestras de trincheras y relevamientos magnetométricos y geoeléctricos terrestres y la interpretación, para la zona de trabajo, de estudios previos de magnetometría aérea y líneas sísmicas. El área del “anticlinal” El Tranquilo, está caracterizada por la presencia de rocas y unidades geológicas con escasa representación en el Macizo del Deseado, y representa una “ventana geológica” que permite el estudio del intervalo Triásico superior - Jurásico inferior, períodos que se encuentran poco expuestos en esta provincia geológica. La secuencia estratigráfica de este sector se inicia con las sedimentitas continentales, areniscas a areniscas conglomerádicas con intercalaciones de pelitas, del Grupo El Tranquilo, del Triásico medio a superior (Jalfin y Herbst 1995). Por encima, se presentan las rocas volcaniclásticas de la Formación Roca Blanca (Herbst, 1965), del Jurásico inferior. Esta es la litología más desarrollada en el área y está compuesta por tufitas, areniscas y sabulitas ricas en componentes volcánicos. Intruyendo a las sedimentitas continentales y a las tufitas, se disponen rocas básicas a intermedias del Jurásico inferior, que se presentan como filones capa de diabasa en el sector este del área y como pórfidos andesíticos de formas subcirculares en el sector noroeste, de la Formación Cerro León (Panza, 1995 y de Barrio et al., 1999). En los sectores norte y noreste del área afloran volcánitas del Jurásico medio a superior, basaltos y andesitas de la Formación Bajo Pobre, y en el sector sudoriental pequeños asomos de ignimbritas riolíticas del Grupo Bahía Laura (Panza, 1995). Estas unidades se encuentran parcialmente cubiertas por el Basalto Las Mercedes del Cretácico superior y el Basalto Cerro del Doce correspondiente al Eoceno (Panza, 1982) y finalizan esta secuencia sedimentos modernos, aluviales, coluviales y de bajos. En la presente investigación se determinó la presencia de niveles ignimbríticos ácidos y coladas basálticas intercaladas en las tufitas de la Formación Roca Blanca. A partir de las edades obtenidas, relaciones estratigráficas y composición se desvincula a los intrusivos dioríticos de la Formación Cerro León y se los asocia con el magmátismo de la Formación La Leona (Jurásico inferior). Los basaltos aflorantes en el área presentan características de basaltos continentales que se corresponden a los primeros indicios del magmatismo sinextensional jurásico y representan magmas básicos de origen mantélico que alcanzaron la superficie. Se los desvinculan de la Formación Bajo Pobre por ser ligeramente más antiguos al estar intercalados entre las tufitas de la Formación Roca Blanca (Jurásico inferior) y por presentar diferentes características isotópicas y petrogenéticas. Se define así una nueva unidad formacional para estas rocas denominándolas Formación El Piche. Los pórfidos andesíticos de la Formación Cerro León y las andesitas de la Formación Bajo Pobre presentan similitudes geoquímicas, isotópicas, petrogenéticas y edades semejantes, por lo que se interpreta un mismo origen para estas rocas, siendo los pórfidos andesíticos partes de los conductos de emisión de las coladas andesíticas. A diferencia del resto del Macizo del Deseado donde predomina casi por completo deformación con comportamiento netamente frágil, en el área de estudio se reconoció deformación tanto dúctil como frágil en las secuencias triásicas y jurásicas. Los rasgos estructurales más sobresalientes son: un domamiento regional de entre 15 a 20 km de diámetro, definido por Di Persia (1956) como “anticlinal” El Tranquilo, domamientos y plegamientos con dimensiones menores a 1 km localizados dentro de la antiforma regional, un sistema de fracturas radiales asociado al domamiento y la falla El Tranquilo con un sistema de vetas controladas por fallas. Se determinó que el “anticlinal” El Tranquilo, se formó por el emplazamiento de un cuerpo intrusivo no aflorante del orden de 8 a 10 Km de diámetro y profundidad mínima hasta su techo de 1400 m, subyaciendo al Grupo El Tranquilo y a la Formación Roca Blanca, y generando por su intrusión, el domamiento regional y los domamientos y plegamientos con dimensiones menores a 1 km localizados corresponde a una deformación producida por lacolitos o stocks no aflorantes. En el área de estudio se reconocieron gran cantidad de mineralizaciones, las que totalizan ~80 km lineales de vetas, ubicadas principalmente en el sector central del área. Las vetas se concentran hacia el este de la estructura regional, la falla El Tranquilo, son subparalelas a esta estructura y están emplazadas en las tufitas de la Formación Roca Blanca y pelitas y areniscas del Grupo El Tranquilo. Se han discriminado dos tipos distintos de vetas según su composición y expresión superficial, vetas formadas por importantes zonas de oxidación que representan la expresión superficial de vetas de sulfuros, y vetas, brechas hidrotermales, vetillas y stockworks formados principalmente por cuarzo. A partir de las distintas características observadas y datos obtenidos (composición, signatura geoquímica, mineralogía, datos de inclusiones fluidas, isótopos, controles estructurales y litológicos y edades) se ha podido diferenciar dos estilos de mineralización. La mineralización polimetálica que presenta una compleja mineralogía de sulfuros asociada a una signatura geoquímica de In, Cu, Au, As, Sn, W, Bi, Zn, Pb, Ag, Cd y Sb. Las temperaturas y salinidades de los fluidos indican un sistema epitermal para la formación de estas vetas. Su génesis esta vinculada a los cuerpos intrusivos dioríticos reducidos por sedimentos ricos en materia orgánica, concentrando en los fluidos hidrotermales In, Sn, Ag, W, Bi. Se define a esta mineralización como un depósito epitermal vetiforme polimetálico rico en In semejante a los depósitos de Japón y Bolivia. Las características de esta mineralización y la edad Jurásica inferior (193 Ma) confirman la presencia de un nuevo tipo de deposito epitermal que difiere del clásico modelo de baja sulfuración del Macizo del Deseado y que no se encuentra asociado al importante volcanismo bimodal del Jurásico medio a superior (Complejo Bahía Laura), como la mayoría de las mineralizaciones del Macizo del Deseado. Este hecho potencia el hallazgo de otros tipos de depósitos epitermales polimetálicos, asociados a otras rocas y con diferentes asociaciones metalogénicas. La mineralización argentífera está formada por cuarzo, carbonatos y en menor medida sulfuros y sulfosales con una signatura geoquímica de Ag (Au), Pb, Cu y Zn. Las temperaturas y salinidades de los fluidos indican un sistema epitermal para la formación de estas vetas. Su génesis está vinculada al magmatismo intermedio de las Formaciones Cerro León y Bajo Pobre, atribuyéndole una edad Jurásica media (168 Ma). Según sus características esta mineralización puede ser definida como un depósito epitermal de sulfuración intermedia. Esta mineralización también representa una variación en el modelo de baja sulfuración del Macizo del Deseado, pero está genéticamente asociada al volcanismo bimodal del Complejo Bahía Laura (Fm. Bajo Pobre) por lo que podría incluirse dentro de las mineralizaciones de la Provincia auroargéntifera del Deseado.
Capítulos de libros sobre el tema "FEM non lineare"
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Funken, S. A. y E. P. Stephan. "Fast Solvers for Non-Linear FEM-BEM Equations". En IABEM Symposium on Boundary Integral Methods for Nonlinear Problems, 63–68. Dordrecht: Springer Netherlands, 1997. http://dx.doi.org/10.1007/978-94-011-5706-3_10.
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Funken, S. A. y E. P. Stephan. "Fast Solvers for Non-Linear Fem-Bem Equations". En Notes on Numerical Fluid Mechanics (NNFM), 181–86. Wiesbaden: Vieweg+Teubner Verlag, 1997. http://dx.doi.org/10.1007/978-3-322-89565-3_16.
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Sogokon, Andrew, Khalil Ghorbal y Taylor T. Johnson. "Decoupling Abstractions of Non-linear Ordinary Differential Equations". En FM 2016: Formal Methods, 628–44. Cham: Springer International Publishing, 2016. http://dx.doi.org/10.1007/978-3-319-48989-6_38.
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Chróścielewski, J., I. Lubowiecka y W. Pietraszkiewicz. "FEM and Time Stepping Procedures in Non-Linear Dynamics of Flexible Branched Shell Structures". En Theories of Plates and Shells, 21–28. Berlin, Heidelberg: Springer Berlin Heidelberg, 2004. http://dx.doi.org/10.1007/978-3-540-39905-6_3.
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Oñate, Eugenio, Francisco Zárate, Miguel A. Celigueta, José M. González, Juan Miquel, Josep M. Carbonell, Ferran Arrufat, Salvador Latorre y Miquel Santasusana. "Advances in the DEM and Coupled DEM and FEM Techniques in Non Linear Solid Mechanics". En Computational Methods in Applied Sciences, 309–35. Cham: Springer International Publishing, 2017. http://dx.doi.org/10.1007/978-3-319-60885-3_15.
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Heise, Bodo. "Parallel Solvers for coupled FEM-BEM equations with applications to non-linear magnetic field problems". En Notes on Numerical Fluid Mechanics (NNFM), 73–85. Wiesbaden: Vieweg+Teubner Verlag, 1995. http://dx.doi.org/10.1007/978-3-322-86859-6_7.
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Gawarecki, L. y V. Mandrekar. "Non-linear filtering with Gaussian martingale noise: Kalman filter with fBm noise". En Institute of Mathematical Statistics Lecture Notes - Monograph Series, 92–97. Beachwood, Ohio, USA: Institute of Mathematical Statistics, 2004. http://dx.doi.org/10.1214/lnms/1196285382.
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Ventura, Giulio. "Single Domain Quadrature Techniques for Discontinuous and Non-Linear Enrichments in Local Partion of Unity FEM". En IUTAM Symposium on Discretization Methods for Evolving Discontinuities, 343–61. Dordrecht: Springer Netherlands, 2007. http://dx.doi.org/10.1007/978-1-4020-6530-9_20.
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Gierczak, Ewa, Maciej Włodarczyk y Kazimierz Adamiak. "Magnetic Field and Force of Linear Induction Motor Fed From Non-sinusoidal Source". En Electromagnetic Fields in Electrical Engineering, 163–69. Boston, MA: Springer US, 1988. http://dx.doi.org/10.1007/978-1-4613-0721-1_30.
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Takács, P. F., K. V. Høiseth, S. I. Sørensen, T. Kanstad, J. A. Øverli y E. Thorenfeldt. "Non-linear analysis of prestressed concrete beams with a total strain based model: FEM model and full-scale testing". En Finite Elements in Civil Engineering Applications, 201–8. London: CRC Press, 2021. http://dx.doi.org/10.1201/9781003211365-28.
Texto completoActas de conferencias sobre el tema "FEM non lineare"
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AZIZI, M., E. M. DAOUDI, R. EL HANI y A. LAKHOUAJA. "PARALLEL NON LINEAR ELECTROMAGNETIC MODELLING WITH FEM". En Proceedings of the International Conference ParCo99. PUBLISHED BY IMPERIAL COLLEGE PRESS AND DISTRIBUTED BY WORLD SCIENTIFIC PUBLISHING CO., 2000. http://dx.doi.org/10.1142/9781848160170_0007.
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Santra, Robin. "Non-linear FEL science". En 2013 Conference on Lasers & Electro-Optics Europe & International Quantum Electronics Conference CLEO EUROPE/IQEC. IEEE, 2013. http://dx.doi.org/10.1109/cleoe-iqec.2013.6801153.
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Satoh, Naoshi, Tetsuya Sakai y Mamoru Aida. "Non-Linear FEM Analysis of the Trunnion Suspension System". En International Truck & Bus Meeting & Exposition. 400 Commonwealth Drive, Warrendale, PA, United States: SAE International, 1991. http://dx.doi.org/10.4271/912714.
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Xu, W. L. "Stiffness Simulation Using Non-linear FEA". En NUMISHEET 2005: Proceedings of the 6th International Conference and Workshop on Numerical Simulation of 3D Sheet Metal Forming Process. AIP, 2005. http://dx.doi.org/10.1063/1.2011210.
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Lund, Espen, Mladen Jecmenica, Hamid Reza Karimi, Kjell G. Robbersmyr y Ole Melteig. "Energy analysis of a non-linear dynamic impact using FEM". En 2014 11th World Congress on Intelligent Control and Automation (WCICA). IEEE, 2014. http://dx.doi.org/10.1109/wcica.2014.7053760.
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Szeri, Andras Z. "Non-Linear Lubricant Behavior in Concentrated Contacts". En ASME 2001 International Mechanical Engineering Congress and Exposition. American Society of Mechanical Engineers, 2001. http://dx.doi.org/10.1115/imece2001/fed-24919.
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Abstract Elastohydrodynamic lubrication (EHL) is the name given to hydrodynamic lubrication when it is applied to solid surfaces of low geometric conformity (counterformal contacts) that are capable of, and are subject to, elastic deformation. In bearings relying on EHL principles, the residence time of the fluid is less than 1 ms, the pressures are up to 4 GP, the film is thin, down to 0.1 μm, and shear rates are up to 108 s−1 — under such conditions lubricants exhibit material behavior that is distinctly different from their behavior in bulk at normal temperature and pressure. In fact, without taking into account the viscosity-pressure characteristics of the liquid lubricant and the elastic deformation of the bounding solids, hydrodynamic theory is unable to explain the existence of continuous lubricant films in highly loaded gears and rolling contact bearings.
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LU, CHENG, A. KIET TIEU y ZHENGYI JIANG. "A SIMPLIFICATION OF NON-LINEAR RIGID PLASTIC FEM FOR ROLLING PROCESS". En Proceedings of the Third Australasian Congress on Applied Mechanics. WORLD SCIENTIFIC, 2002. http://dx.doi.org/10.1142/9789812777973_0057.
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Shen, J. y R. L. Kushwaha. "A Non-Linear and Dynamic FEM Software for Machine-Soil System". En International Off-Highway & Powerplant Congress & Exposition. 400 Commonwealth Drive, Warrendale, PA, United States: SAE International, 1994. http://dx.doi.org/10.4271/941743.
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Ledesma-Orozco, E. R., J. A. Diosdado-De la Pen˜a, G. I. Pe´rez–Soto, A. Salazar-Garibay, J. F. Reveles-Arredondo, G. Villalobos-Llamas y P. Dura´n-Rese´ndiz. "Non-Linear Analysis of Energy Absorption Systems Under Impact Loads Through FEM". En ASME 2011 International Mechanical Engineering Congress and Exposition. ASMEDC, 2011. http://dx.doi.org/10.1115/imece2011-64471.
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This paper presents the non-linear simulation of the impact on a structure with different energy absorption systems using finite element models. A comparison of the damage caused to the structure in case of impact without implementing energy absorption system, and implementing energy absorption systems based on bistable structures, polystyrene foam and aluminium foam are shown here in. The results demonstrate the advantages of using energy absorption systems on structures under impact loads.
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Azzouz, M. Salim, Xinyun Guo, Adam Przekop y Chuh Mei. "Comparison of PDE/Galerkin and FEM for Non-linear Aerospace Structure Analyses". En 44th AIAA/ASME/ASCE/AHS/ASC Structures, Structural Dynamics, and Materials Conference. Reston, Virigina: American Institute of Aeronautics and Astronautics, 2003. http://dx.doi.org/10.2514/6.2003-1856.
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Khan, Mahreen. Lessons from Adaptive Programming. Institute of Development Studies, septiembre de 2022. http://dx.doi.org/10.19088/k4d.2022.142.
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The aim of adaptive programming (AP) is to produce adaptive, flexible, iterative, responsive, problem-driven, politically smart, locally led programmes which are effective and efficient and meet donor requirements for accountability. This is a rapid desk review of recent literature on AP including academic and grey sources. Section 2 covers the main challenges and barriers to successful implementation of AP. Key success factors are covered in Section 3. Selecting the appropriate monitoring and evaluation tools such as outcome harvesting or adapted versions of Value for Money to assist in measuring outcomes and embedding learning is key to successful AP, particularly in governance programmes, where results are usually long-term, non-linear and causality can be difficult to specifically trace back to the donor-funded intervention. Section 4 details three case studies from the governance arena as this report was requested to assist in designing adaptive governance programmes. Thus, the State Accountability and Voice Initiative (SAVI) from Nigeria, Chakua Hatua from Tanzania, and Within and Without the State (WWS) from conflict regions are included to show how flexible indicators, donor communication and negotiation, empowering teams and adopting monitoring and evaluation tools assisted in successful AP outcomes in different locations and political contexts. The challenges faced and drawbacks of certain processes were fed into efficient feedback loops fostering cross-communication, adaptation, and modification to ensure procedures and policies were changed accordingly. Sources used are primarily from the previous 5 years, as per K4D norms, unless the work is seminal, such as the ODI Report (2016) Doing Development Differently, which encouraged over 60 countries to sign up for the AP methodology. This review found a substantive body of literature on AP methodology the relative recency of academic attention on AP in the development less evidence is available on case studies of AP in the development sector, as there are not many ongoing projects and even fewer have been completed and results assessed (ICF, 2019). There is also a lack of case studies on how dynamic, empowered, innovative teams successfully apply adaptive programming ideas, particularly providing behavioural insights about such teams (Cooke, 2017) as well as little attention to precipitating and sustaining behaviour change in institutions over the longer term (Power, 2017).
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Varga, Gabriella A., Amichai Arieli, Lawrence D. Muller, Haim Tagari, Israel Bruckental y Yair Aharoni. Effect of Rumen Available Protein, Amimo Acids and Carbohydrates on Microbial Protein Synthesis, Amino Acid Flow and Performance of High Yielding Cows. United States Department of Agriculture, agosto de 1993. http://dx.doi.org/10.32747/1993.7568103.bard.
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The effect of rumen available protein amino acids and carbohydrates on microbial protein synthesis, amino acid flow and performance of high yielding dairy cows was studied. A significant relationship between the effective degradabilities of OM in feedstuffs and the in vivo ruminal OM degradation of diets of dairy cows was found. The in situ method enabled the prediction of ruminal nutrients degradability response to processing of energy and nitragenous supplements. The AA profile of the rumen undegradable protein was modified by the processing method. In a continuous culture study total N and postruminal AA flows, and bacterial efficiency, is maximal at rumen degradable levels of 65% of the CP. Responses to rumen degradable non carbohydrate (NSC) were linear up to at least 27% of DM. Higher CP flow in the abomasum was found for cows fed high ruminally degradable OM and low ruminally degradable CP diet. It appeared that in dairy cows diets, the ratio of rumen degradable OM to rumenally degradable CP should be at least 5:1 in order to maximize postruminal CP flow. The efficiency of microbial CP synthesis was higher for diets supplemented with 33% of rumen undegradable protein, with greater amounts of bacterial AA reaching the abomasum. Increase in ruminal carbohydrate availability by using high moisture corn increased proportions of propionate, postruminal nutrients flow, postruminal starch digestibility, ruminal availability of NSC, uptake of energy substrates by the mammory gland. These modifications resulted with improvement in the utilization of nonessential AA for milk protein synthesis, in higher milk protein yield. Higher postruminal NSC digestibility and higher efficiency of milk protein production were recorded in cows fed extruded corn. Increasing feeding frequency increased flow of N from the rumen to the blood, reduced diurnal variation in ruminal and ammonia, and of plasma urea and improved postruminal NSC and CIP digestibility and total tract digestibilities. Milk and constituent yield increased with more frequent feeding. In a study performed in a commercial dairy herd, changes in energy and nitrogenous substrates level suggested that increasing feeding frequency may improve dietary nitrogen utilization and may shift metabolism toward more glucogenesis. It was concluded that efficiency of milk protein yield in high producing cows might be improved by an optimization of ruminal and post-ruminal supplies of energy and nitrogenous substrates. Such an optimization can be achieved by processing of energy and nitrogenous feedstuffs, and by increasing feeding frequency. In situ data may provide means for elucidation of the optimal processing conditions.
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Salcido, Charles, Patrick Wilson, Justin Tweet, Blake McCan, Clint Boyd y Vincent Santucci. Theodore Roosevelt National Park: Paleontological resource inventory (public version). National Park Service, mayo de 2022. http://dx.doi.org/10.36967/nrr-2293509.
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Theodore Roosevelt National Park (THRO) in western North Dakota was established for its historical connections with President Theodore Roosevelt. It contains not only historical and cultural resources, but abundant natural resources as well. Among these is one of the best geological and paleontological records of the Paleocene Epoch (66 to 56 million years ago) of any park in the National Park System. The Paleocene Epoch is of great scientific interest due to the great mass extinction that occurred at its opening (the Cretaceous–Paleogene extinction event), and the unusual climatic event that began at the end of the epoch (the Paleocene–Eocene Thermal Maximum, an anomalous global temperature spike). It is during the Paleocene that mammals began to diversify and move into the large-bodied niches vacated by dinosaurs. The rocks exposed at THRO preserve the latter part of the Paleocene, when mammals were proliferating and crocodiles were the largest predators. Western North Dakota was warmer and wetter with swampy forests; today these are preserved as the “petrified forests” that are one of THRO’s notable features. Despite abundant fossil resources, THRO has not historically been a scene of significant paleontological exploration. For example, the fossil forests have only had one published scientific description, and that report focused on the associated paleosols (“fossil soils”). The widespread petrified wood of the area has been known since at least the 19th century and was considered significant enough to be a tourist draw in the decades leading up to the establishment of THRO in 1947. Paleontologists occasionally collected and described fossil specimens from the park over the next few decades, but the true extent of paleontological resources was not realized until a joint North Dakota Geological Survey–NPS investigation under John Hoganson and Johnathan Campbell between 1994–1996. This survey uncovered 400 paleontological localities within the park representing a variety of plant, invertebrate, vertebrate, and trace fossils. Limited investigation and occasional collection of noteworthy specimens took place over the next two decades. In 2020, a new two-year initiative to further document the park’s paleontological resources began. This inventory, which was the basis for this report, identified another 158 fossil localities, some yielding taxa not recorded by the previous survey. Additional specimens were collected from the surface, among them a partial skeleton of a choristodere (an extinct aquatic reptile), dental material of two mammal taxa not previously recorded at THRO, and the first bird track found at the park. The inventory also provided an assessment of an area scheduled for ground-disturbing maintenance. This inventory is intended to inform future paleontological resource research, management, protection, and interpretation at THRO. THRO’s bedrock geology is dominated by two Paleocene rock formations: the Bullion Creek Formation and the overlying Sentinel Butte Formation of the Fort Union Group. Weathering of these formations has produced the distinctive banded badlands seen in THRO today. These two formations were deposited under very different conditions than the current conditions of western North Dakota. In the Paleocene, the region was warm and wet, with a landscape dominated by swamps, lakes, and rivers. Great forests now represented by petrified wood grew throughout the area. Freshwater mollusks, fish, amphibians (including giant salamanders), turtles, choristoderes, and crocodilians abounded in the ancient wetlands, while a variety of mammals representing either extinct lineages or the early forebearers of modern groups inhabited the land. There is little representation of the next 56 million years at THRO. The only evidence we have of events in the park for most of these millions of years is isolated Neogene lag deposits and terrace gravel. Quaternary surficial deposits have yielded a few fossils...
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Khan, Mahreen. Public Financial Management and Transitioning out of Aid. Institute of Development Studies, septiembre de 2022. http://dx.doi.org/10.19088/k4d.2022.145.
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This rapid review found an absence of literature focused specifically on measuring the impact of PFM and governance systems in countries that have transitioned from aid, by moving up the income ladder. However, there are a few academic publications and a limited number of studies by multilateral, such as the World Bank, that examine the role of PFM and governance systems in countries that are transitioning or have moved away from aid. However, the importance of public financial management (PFM) and governance systems in development is well established and seen as a pre-requisite for economic growth. To effectively transition from aid, most low-income countries (LICs) need to upgrade their PFM and governance systems to meet the different scale, resources, accountability mechanisms, and capacity-building requirements of a middle-income country (MIC). The absence of the above empirical evidence may be due to the complexity of measuring the impact of PFM reforms as the results are non-linear, difficult to isolate from other policies to establish causality, and manifest in a longer time frame. However, through comparative country studies, the consequences of deficient PFM and governance have been well documented. So impaired budgetary planning, implementation, and reporting, limited fiscal transparency, weak accountability mechanisms, resource leakage, and inefficient service delivery are well recognised as detrimental to economic growth and development. The literature on transitioning countries focuses predominantly on the impact of aid withdrawal on the social sector, where comparative qualitative data is easier to obtain and the effects are usually more immediate, visible, and may even extend to global health outcomes, such as in AIDS prevention programmes. Thus, tracking the progress of donor-assisted social sector programmes is relatively easier than for PFM and governance reforms. The literature is more abundant on the overall lessons of transitions from aid both for country governments and donors. The key lessons underscore the importance of PFM and governance systems and mechanisms to a successful transition up the income ladder: Planning for transition should be strategic, detailed and specifically geared to mitigate against risks, explicitly assessing the best mix of finance options to mitigate the impact of aid reduction/withdrawal on national budgets. The plan must be led by a working group or ministry and have timelines and milestones; Where PFM and governance is weak transition preparation should include strengthening PFM especially economic and fiscal legislation, administration, and implementation; Stakeholders such as donor partners (DPs) and NGOs should participate in the planning process with clear, open, and ongoing communication channels; Political and economic assessments in the planning and mid-term phases as well as long-term monitoring and evaluation should be instituted; Build financial, technical, and management capacity throughout the plan implementation This helpdesk report draws on academic, policy, and grey sources from the previous seven years rather than the usual K4D five-year window, to account for the two-year disruption of COVID-19. As cross-country studies on PFM and governance are scarce, a few older studies are also referenced to ensure a comprehensive response to the query. The report focuses on low-income countries transitioning from aid due to a change in status to lower-middle-income countries.
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Fromm, Hillel, Paul Michael Hasegawa y Aaron Fait. Calcium-regulated Transcription Factors Mediating Carbon Metabolism in Response to Drought. United States Department of Agriculture, junio de 2013. http://dx.doi.org/10.32747/2013.7699847.bard.
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Original objectives: The long-term goal of the proposed research is to elucidate the transcription factors, genes and metabolic networks involved in carbon metabolism and partitioning in response to water deficit. The proposed research focuses on the GTLcalcium/calmodulinbindingTFs and the gene and metabolic networks modulated by these TFs in Arabidopsis thaliana. The specific objectives are as follows. Objective-1 (USA): Physiological analyses of GTL1 loss- and gain-of-function plants under water sufficient and drought stress conditions Objective 2 (USA / Israel-TAU): Characterizion of GTL target genes and bioinformatic analysis of data to eulcidate gene-network topology. Objective-3 (Israel-TAU): Regulation of GTLmediated transcription by Ca²⁺/calmodulin: mechanism and biological significance. Objective-4 (Israel-BGU): Metabolic networks and carbon partitioning in response to drought. Additional direction: In the course of the project we added another direction, which was reported in the 2nd annual report, to elucidate genes controlling drought avoidance. The TAU team has isolated a few unhydrotropic (hyd) mutants and are in the process of mapping these mutations (of hyd13 and hyd15; see last year's report for a description of these mutants under salt stress) in the Arabidopsis genome by map-based cloning and deep sequencing. For this purpose, each hyd mutant was crossed with a wild type plant of the Landsberg ecotype, and at the F2 stage, 500-700 seedlings showing the unhydrotropic phenotype were collected separately and pooled DNA samples were subkected to the Illumina deep sequencing technology. Bioinformatics were used to identify the exact genomic positions of the mutations (based on a comparison of the genomic sequences of the two Arabidopsis thaliana ecotypes (Columbia and Landsberg). Background: To feed the 9 billion people or more, expected to live on Earth by the mid 21st century, the production of high-quality food must increase substantially. Based on a 2009 Declaration of the World Summit on Food Security, a target of 70% more global food production by the year 2050 was marked, an unprecedented food-production growth rate. Importantly, due to the larger areas of low-yielding land globally, low-yielding environments offer the greatest opportunity for substantial increases in global food production. Nowadays, 70% of the global available water is used by agriculture, and 40% of the world food is produced from irrigated soils. Therefore, much needs to be done towards improving the efficiency of water use by plants, accompanied by increased crop yield production under water-limiting conditions. Major conclusions, solutions and achievements: We established that AtGTL1 (Arabidopsis thaliana GT-2 LIKE1) is a focal determinant in water deficit (drought) signaling and tolerance, and water use efficiency (WUE). The GTL1 transcription factor is an upstream regulator of stomatal development as a transrepressor of AtSDD1, which encodes a subtilisin protease that activates a MAP kinase pathway that negatively regulates stomatal lineage and density. GTL1 binds to the core GT3 cis-element in the SDD1 promoter and transrepresses its expression under water-sufficient conditions. GTL1 loss-of-function mutants have reduced stomatal number and transpiration, and enhanced drought tolerance and WUE. In this case, higher WUE under water sufficient conditions occurs without reduction in absolute biomass accumulation or carbon assimilation, indicating that gtl1-mediated effects on stomatal conductance and transpiration do not substantially affect CO₂ uptake. These results are proof-of-concept that fine-tuned regulation of stomatal density can result in drought tolerance and higher WUE with maintenance of yield stability. Implications: Accomplishments during the IS-4243-09R project provide unique tools for continued discovery research to enhance plant drought tolerance and WUE.
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CHARACTERISATION OF THE BEHAVIOUR OF BEAM-TO-COLUMN STEEL JOINTS UP TO FAILURE. The Hong Kong Institute of Steel Construction, septiembre de 2022. http://dx.doi.org/10.18057/ijasc.2022.18.3.5.
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The design of steel joints is currently dealt with in Eurocode 3 through the well-known “component method”. In particular, Part 1-8 of this standard provides guidance on how to apply the method to a wide range of joint configurations allowing to assess the latter’s initial rotational stiffness and resistance. Nonetheless, whenever a global structural plastic analysis is contemplated, provisions of Eurocode 3 are insufficient since no clear guidance on how to determine the ultimate resistance and the ultimate rotation capacity of joints is provided. In this paper, the full-range behaviour of beam-to-column steel joints is investigated using experimental, analytical, and numerical methods. A new analytical approach based on the component method is proposed and validated against five physical experiments. Through additional analytical expressions for the characterisation of basic components of steel joints, the proposed approach extends the applicability of the component method such that strain-hardening and ductility of components are accounted for. The results show a good agreement between the analytical prediction and the experimental results and also highlight specific limitations of the classical component method. Three-dimensional finite element (FE) models are also employed to simulate the behaviour of the tested beam-to-column joints. The results prove the accuracy of numerical models to simulate the non-linear response of steel joints emphasizing, however, the importance of proper modelling assumptions.