Academic literature on the topic 'Non Cartan dynamics'
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Journal articles on the topic "Non Cartan dynamics"
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Bondarenko, Sergey. "Dynamical Signature: Complex Manifolds, Gauge Fields and Non-Flat Tangent Space." Universe 8, no. 10 (September 22, 2022): 497. http://dx.doi.org/10.3390/universe8100497.
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Theoretical possibilities of models of gravity with dynamical signature are discussed. The different scenarios of the signature change are proposed in the framework of Einstein-Cartan gravity. We consider, subsequently, the dynamical signature in the model of the complex manifold with complex coordinates and complex metrics are introduced, a complexification of the manifold and coordinates through new gauge fields, an additional gauge symmetry for the Einstein-Cartan vierbein fields, and non-flat tangent space for the metric in the Einstein-Cartan gravity. A new small parameter, which characterizes a degree of the deviation of the signature from the background one, is introduced in all models. The zero value of this parameter corresponds to the signature of an initial background metric. In turn, in the models with gauge fields present, this parameter represents a coupling constant of the gauge symmetry group. The mechanism of metric determination through induced gauge fields with defined signatures in the corresponding models is considered. The ways of the signature change through the gauge field dynamics are reviewed, and the consequences and applications of the proposed ideas are discussed as well.
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Rubin, Jacques. "Applications of a Particular Four-Dimensional Projective Geometry to Galactic Dynamics." Galaxies 6, no. 3 (August 3, 2018): 83. http://dx.doi.org/10.3390/galaxies6030083.
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Relativistic localizing systems that extend relativistic positioning systems show that pseudo-Riemannian space-time geometry is somehow encompassed in a particular four-dimensional projective geometry. The resulting geometric structure is then that of a generalized Cartan space (also called Cartan connection space) with projective connection. The result is that locally non-linear actions of projective groups via homographies systematically induce the existence of a particular space-time foliation independent of any space-time dynamics or solutions of Einstein’s equations for example. In this article, we present the consequences of these projective group actions and this foliation. In particular, it is shown that the particular geometric structure due to this foliation is similar from a certain point of view to that of a black hole but not necessarily based on the existence of singularities. We also present a modified Newton’s laws invariant with respect to the homographic transformations induced by this projective geometry. Consequences on galactic dynamics are discussed and fits of galactic rotational velocity curves based on these modifications which are independent of any Modified Newtonian Dynamics (MOND) or dark matter theories are presented.
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Agop, Maricel, Tudor-Cristian Petrescu, Dumitru Filipeanu, Claudia Elena Grigoraș-Ichim, Ana Iolanda Voda, Andrei Zala, Lucian Dobreci, Constantin Baciu, and Decebal Vasincu. "Toward Complex Systems Dynamics through Flow Regimes of Multifractal Fluids." Symmetry 13, no. 5 (April 27, 2021): 754. http://dx.doi.org/10.3390/sym13050754.
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In the framework of the Multifractal Theory of Motion, which is expressed by means of the multifractal hydrodynamic model, complex system dynamics are explained through uniform and non-uniform flow regimes of multifractal fluids. Thus, in the case of the uniform flow regime of the multifractal fluid, the dynamics’ description is “supported” only by the differentiable component of the velocity field, the non-differentiable component being null. In the case of the non-uniform flow regime of the multifractal fluid, the dynamics’ description is “supported” by both components of the velocity field, their ratio specifying correlations through homographic transformations. Since these transformations imply metric geometries explained, for example, by means of Killing–Cartan metrics of the SL(2R)-type algebra, of the set of 2 × 2 matrices with real elements, and because these metrics can be “produced” as Cayleyan metrics of absolute geometries, the dynamics’ description is reducible, based on a minimal principle, to harmonic mappings from the usual space to the hyperbolic space. Such a conjecture highlights not only various scenarios of dynamics’ evolution but also the types of interactions “responsible” for these scenarios. Since these types of interactions become fundamental in the self-structuring processes of polymeric-type materials, finally, the theoretical model is calibrated based on the author’s empirical data, which refer to controlled drug release applications.
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Kasem, Ammar, and Shaaban Khalil. "Gauge-field-induced torsion and cosmic inflation." International Journal of Modern Physics A 36, no. 21 (July 30, 2021): 2150161. http://dx.doi.org/10.1142/s0217751x2150161x.
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In this paper, inflation in the framework of Einstein–Cartan theory is revisited. Einstein–Cartan theory is a natural extension of the General Relativity with nonvanishing torsion. The connection on Riemann–Cartan space–time is only compatible with the cosmological principal for a particular form of torsion. We also show this form to be compatible with gauge invariance principle for non-Abelian and Abelian gauge fields under a certain deviced coupling procedure. We adopt an Abelian gauge field in the form of “cosmic triad”. The dynamical field equations are obtained and shown to sustain cosmic inflation with a large number of e-folds. We emphasize that at the end of inflation, torsion vanishes and the theory of Einstein–Cartan reduces to the General Relativity with the usual FRW geometry.
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Podrigalo, Mikhail, Volodymyr Peregon, Oleksandr Boboshko, Dmitrij Bogdan, and Oleksandr Koriak. "Kinematics of Hooke’s Joint." Vehicle and electronics. Innovative technologies, no. 21 (July 2, 2022): 48–56. http://dx.doi.org/10.30977/veit.2022.21.0.09.
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Problem. An analysis of the literature has shown that some issues of the kinematics and dynamics of the Hooke’s joint are not fully covered. In particular, this applies to the determination of the kinematic characteristics of the relative movements of the links in the movable joints of the crosspieces and cardan yokes, as well as the acceleration of the crosspiece in the study of the hinge. These kinematic characteristics are the basis for dynamic analysis of the cardan transmission; they are used at research of operation of the bearings of a cardan joint cross; they are necessary to determine the energy expended to overcome the forces of friction in these kinematic pairs; they form the basis for evaluating transmission efficiency. Goal. The goal of this work is to determine the kinematic characteristics of the cross in its absolute and relative motions. Methodology. The research is based on the graphical and analytical method of kinematic analysis of spherical motion of a rigid body. At the initial stage, the calculated dependences for determining the angular velocity of the cross in its absolute and relative motions were obtained. The relative angles of rotation of the links in the movable joints of the crosspiece and cardan yokes were determined by integrating the corresponding differential equations. To determine the angular acceleration of the crosspiece, the theorem on the addition of angular accelerations of a rigid body rotating around two non-parallel axes was used. Results. The study of the kinematics of the cardan joint made it possible to identify and eliminate ambiguities in determining the relative angular velocities of the elements of the kinematic pairs of the cross and cardan yokes. Functional dependences for determination of angular acceleration of a crosspiece in absolute and relative movements, and also relative angles of rotation of links in kinematic pairs of a crosspiece and cardan yokes were received. It was shown that the angular acceleration of the crosspiece is a periodic function of the angle of rotation of the input link. During the operation of the hinge, the crosspiece creates insignificant periodic dynamic loads, which should be taken into account in accurate calculations of high-speed cardan transmissions. Practical value. The work is devoted to the study of the kinematics of the asynchronous hinge, which is the foundation for its dynamic analysis and ultimately aimed at improving the output performance of the cardan transmission. The research method combines mathematical calculations with simplicity and clarity of graphic constructions, which contributes to a deeper understanding of the kinematic features of a hinge of uneven angular velocities. The obtained results can be used in the design and study of motor-transmission units, which include the Hooke’s joint.
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Šuk, Jaroslav, Kateřina Hamouzová, Jana Hajšlová, and Miroslav Jursík. "Dynamics of herbicides degradation in carrot (Daucus carota L.) roots and leaves." Plant, Soil and Environment 67, No. 6 (May 21, 2021): 353–59. http://dx.doi.org/10.17221/46/2021-pse.
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This research had two main aims. First, to analyse the degradation dynamics of herbicides commonly used in carrot (aclonifen, clomazone, flufenacet, linuron, metribuzin, pendimethalin, S-metolachlor). Second, to compare the amount of herbicide residues with the maximum residue level and with requirements of non-residual production. The field experiments were conducted in 2012–2016. All tested herbicides resulted in relatively low concentrations of residues in carrot roots (up to 10 µg/kg) when the recommended withdrawal period was followed between application and harvest. The concentration of S-metolachlor in carrot roots exceeded the maximal residual limit (MRL) if the application was carried out four days before harvest. The measured values of other tested herbicide residues in carrot roots did not exceed the MRL in any of the tested samples. Pre-emergent use of clomazone, linuron and flufenacet could be recommended for non-residue carrot production. Post-emergent use of metribuzin can be used for non-residue carrot production if the interval between application and harvest is at least 80 days. Concentrations of herbicide residues in carrot leaves were many times higher than in roots. All tested herbicides can be applied for safe carrot production if applicators adhere to the requirements for use.
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DE BERREDO-PEIXOTO, GUILHERME, and EMANUEL ANTONIO DE FREITAS. "ON THE COSMOLOGICAL EFFECTS OF THE WEYSSENHOFF SPINNING FLUID IN THE EINSTEIN-CARTAN FRAMEWORK." International Journal of Modern Physics A 24, no. 08n09 (April 10, 2009): 1652–55. http://dx.doi.org/10.1142/s0217751x09045170.
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The effects of non-Riemannian structures in Cosmology have been studied long ago and are still a relevant subject of investigation. In the seventies, it was discovered that singularity avoidance and early accelerated expansion can be induced by torsion in the Einstein-Cartan theory. In this framework, torsion is not dynamical and is completely expressed by means of the spin sources. Thus, in order to study the effects of torsion in the Einstein-Cartan theory, one has to introduce matter with spin. In principle, this can be done in several ways. In this work we consider the cosmological evolution of the universe in the presence of a constant isotropic and homogeneous axial current and the Weyssenhoff spinning fluid. We analyse possible solutions of this model, with and without the spinning fluid.
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DAS, SUMIT R., AVINASH DHAR, GAUTAM MANDAL, and SPENTA R. WADIA. "BOSONIZATION OF NON-RELATIVISTIC FERMIONS AND W-INFINITY ALGEBRA." Modern Physics Letters A 07, no. 01 (January 10, 1992): 71–83. http://dx.doi.org/10.1142/s021773239200344x.
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We discuss the bosonization of non-relativistic fermions in one-space dimension in terms of bilocal operators which are naturally related to the generators of W-infinity algebra. The resulting system is analogous to the problem of a spin in a magnetic field for the group W-infinity. The new dynamical variables turn out to be W-infinity group elements valued in the coset W-infinity/H where H is a Cartan subalgebra. A classical action with an H gauge invariance is presented. This action is three-dimensional. It turns out to be similar to the action that describes the color degrees of freedom of a Yang–Mills particle in a fixed external field. We also discuss the relation of this action with the one recently arrived at in the Euclidean continuation of the theory using different coordinates.
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Tomchina, Olga P. "Control of vibrational field in an elastic vibration unit with DC motors and time-varying observer." Cybernetics and Physics, Volume 10, 2021, Number 4 (December 31, 2021): 277–86. http://dx.doi.org/10.35470/2226-4116-2021-10-4-277-286.
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In the paper the problem of feedback control of vibrational fields in a vibration unit is analyzed taking into account the influence of the elasticity of cardan shafts, the drive dynamics, saturation for control torques. In addition, the synthesized rotor synchronization control algorithm uses the estimates of a non-stationary observer, which makes it possible to implement it practically on a two-rotor vibration unit SV-2. The performance of the closed loop mechatronic systems is examined by simulation for the model of the two-rotor vibration unit SV-2.
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Fang, Yong, and Patrick Foulon. "On Finsler manifolds of negative flag curvature." Journal of Topology and Analysis 07, no. 03 (May 15, 2015): 483–504. http://dx.doi.org/10.1142/s1793525315500181.
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One of the key differences between Finsler metrics and Riemannian metrics is the non-reversibility, i.e. given two points p and q, the Finsler distance d(p, q) is not necessarily equal to d(q, p). In this paper, we build the main tools to investigate the non-reversibility in the context of large-scale geometry of uniform Finsler Cartan–Hadamard manifolds. In the second part of this paper, we use the large-scale geometry to prove the following dynamical theorem: Let φ be the geodesic flow of a closed negatively curved Finsler manifold. If its Anosov splitting is C2, then its cohomological pressure is equal to its Liouville metric entropy. This result generalizes a previous Riemannian result of U. Hamenstädt.
Dissertations / Theses on the topic "Non Cartan dynamics"
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Terna, Stefano. "Strong Coupling Analysis of D=2 and D=4 Maximally Supersymmetric YM Theories." Doctoral thesis, SISSA, 2000. http://hdl.handle.net/20.500.11767/4330.
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Cannon, James J. "Non-equilibrium molecular dynamics simulations of flow through carbon nanotubes." Thesis, University of Surrey, 2009. http://epubs.surrey.ac.uk/843548/.
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With increasing pressure on resources, filtration plays a key role in the lives of everyone on this planet. This can, for example, be in terms of desalination to obtain clean drinking water, hydrocarbon separation for gasoline production, or gas separation to meet stringent environmental regulations. In the design of membranes for applications such as these, fast transport of atoms combined with high selectivity is desired, and aligned carbon nanotube membranes show great promise in this respect. In order to design and tailor nanotube-membranes for optimum performance in specific applications, an understanding of the fundamental non-equilibrium flow properties through nanotubes is crucial. The aim of the research described in this thesis is to study these fundamental properties in a systematic fashion, in order to gain a better understanding of the potential that carbon nanotubes have for use in filtration and separation technologies. This research presents a new non-equilibrium molecular dynamics simulation written by this author, capable of reproducing and analysing long-time-scale non-equilibrium flow through carbon structures. Counter-intuitive flow dynamics as well as enhanced flux are demonstrated, and the reasons behind such phenomena are explained. The ability to manipulate the flow on the nano-scale through mechanical means is limited, and this research shows the potential role that nanotubes can play in manipulating the flow and inducing usual flow phenomena. The flow of point-particles is contrasted with that of diatomic molecules, and the level down to which macro-scale laws apply are discussed. Finally, the role of charge on the flow is also highlighted by considering the entry of water into nanotubes. By making these studies, a much greater insight into the potential role of nanotubes in filtration and separation applications is obtained. This research demonstrates that nanotube- membranes have great potential to help overcome the challenges facing the world, today as well as in the future.
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Martin, Willis. "Simulation study of non-covalent hybridization of carbon nanotubes by single-stranded DNA in water." Thesis, Boston College, 2010. http://hdl.handle.net/2345/1169.
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Thesis advisor: Goran KrilovSolubilization and separation is an important step in utilizing both the unique mechanical and electrical properties of carbon nanotubes (CNTs). Due to different possible chiralities of CNTs, which can have drastically different electrochemical properties, it is also necessary to have a method of separation that will distinguish between these different species. Recent discovery of single-stranded DNA (ssDNA) absorption onto CNTs have shown high affinity towards forming soluble hybrids in polar solvents. The interactions between the ssDNA and CNTs as well as the geometry of the hybrid structure are not well understood. In order to study these phenomena we have implemented multiple all-atom replica exchange simulations. Simulations are carried out in an aqueous environment and vary in single-stranded decamer composition as well as nanotube chirality. The oligonucleotides readily adsorb onto the carbon nanotube surface and immediately following begin a slow structural rearrangement. Dependent upon both oligonucleotide composition and nanotube chirality, the ssDNA is found to form several unique backbone geometries as defined by both local and global order parameters. In contrast to the multiple geometries the backbone may form to, the nucleotide bases are found to organize themselves into either parallel or anti-parallel conformation with a high degree of orientational order. Binding appears to be mainly driven by π-stacking interactions between DNA bases onto the carbon nanotube surface, equilibrium of the structures is also controlled by a complex mixture of forces including DNA conformational strain and solvent interactions. The result of this is the free energy landscape is found to have multiple minima occupied at room temperature which are separated by high energy barriers
Thesis (MS) — Boston College, 2010
Submitted to: Boston College. Graduate School of Arts and Sciences
Discipline: Chemistry
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Evteev, Alexander V., Elena V. Levchenko, Irina V. Belova, and Graeme E. Murch. "Molecular dynamics study of carbon diffusion in cementite." Universitätsbibliothek Leipzig, 2016. http://nbn-resolving.de/urn:nbn:de:bsz:15-qucosa-193325.
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Steele, Brad. "Non-equilibrium melting and sublimation of graphene simulated with two interatomic potentials." Scholar Commons, 2013. http://scholarcommons.usf.edu/etd/4586.
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The mechanisms of the sublimation of graphene at zero pressure and the condensation of carbon vapor is investigated by molecular dynamics (MD) simulations. The interatomic interactions are described by the Reactive Empirical Bond Order potential (REBO). It is found that graphene sublimates at a temperature of 5,200 K. At the onset of sublimation, defects that contain several pentagons and heptagons are formed, that are shown to evolve from double vacancies and stone wales defects. These defects consisting of pentagons and heptagons act as nucleation sites for the gaseous phase. The influence of the interatomic interactions on the sublimation process are also investigated by comparing the results using the REBO potential with the Screened Environment Dependent (SED)-REBO potential. Two-dimensional MD simulations are also performed, and it is found that graphene melts at a much higher temperature and forms many more point defects than in three dimensions. It is also observed that carbon chains make up the two-dimensional molten state.
The isothermal equation of state of gaseous and liquid carbon, as well as the coexistence of the two phases is calculated at 6,000 K and up to a few GPa. The analysis shows that the material that forms immediately following the phase transformation in graphene is actually a coexistence of liquid and gaseous phases, but it is primarily two-fold coordinated, so it is mostly a gas, hence the identification of the phase transformation as sublimation. The coexistence pressure for liquid and gaseous carbon is found using the Maxwell Construction to be 0.0365 GPa at 6,000 K. It was previously believed that carbon vapor consists exclusively of carbon chains. We find that under compression, at a pressure lower than the coexistence pressure, carbon vapor develops a small amount (6 %) of sp2 bonds indicating a slight non-chain bonding character. The diffusion coefficient of this dense gas is calculated to be in between that of the liquid and gaseous phases.
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Onyestyák, György, Zsolt Ötvös, Imre Kiricsi, and Lovat V. C. Rees. "The sorption dynamics of C 3 hydrocarbons over carbon nanotubes." Universitätsbibliothek Leipzig, 2016. http://nbn-resolving.de/urn:nbn:de:bsz:15-qucosa-194893.
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Carbon nanotubes obtained by the catalytic vapor deposition (CVD) method were purified by various procedures to obtain samples in pure and well-defined forms. The frequency response (FR) technique was employed to determine the sorption dynamics of C3-hydrocarbons in these samples. Two parallel sorption processes were found, characterized by different sorption capacities and time constants and were assigned to sorption on the convex and concave surfaces of the carbon tubes, respectively. Over a carbon nanotube sample at low coverage the mass transport is little influenced by the different chemical nature of the various C3 hydrocarbons. However the dynamic sorption
properties of carbon nanotube preparations were shown to be strongly affected by the absence or presence of surface functional groups on the outer and inner surfaces of the tube walls. Different rate-determining mechanisms were observed for the samples functionalized to different extents.
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Onyestyák, György, Zsolt Ötvös, Jozsef Valyon, Imre Kiricsi, and Lovat V. C. Rees. "The sorption dynamics of C 3 hydrocarbons over carbon nanotubes." Universitätsbibliothek Leipzig, 2016. http://nbn-resolving.de/urn:nbn:de:bsz:15-qucosa-196636.
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Tognolini, S. "TRACKING THE INTERFACE STATES DYNAMICS AT CARBON-BASED NANOSTRUCTURES ON METAL BY NON-LINEAR PHOTOEMISSION SPECTROSCOPY." Doctoral thesis, Università degli Studi di Milano, 2016. http://hdl.handle.net/2434/362868.
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After single-layer graphene isolation in 2004, the scientific community has concentrated its efforts in the investigation of single-atom thin materials, due to their unique electronic properties, not shown by their bulk counterpart. Among this promising class of materials, two-dimensional carbon-based nanostructures have encountered a growing interest in nanotechnology, due to the huge variety of potential applications in which they are involved, from optoelectronics and photonics to energy generation, storage and solar cells. For the industrial realization of these devices a comprehensive understanding of the interaction between 2D carbon nanostructures and metallic substrates is necessary. An excellent tool to accomplish this aim is represented by the study of the electronic properties and dynamics of the states localized at the carbon nanostructures/metal interfacial region, being extremely sensitive to any modification at the surface. The investigation of these unoccupied electronic states has been accomplished applying femtosecond, high intensity laser pulses in the near-UV ranges to photoemission techniques.
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Cavalli, D. "CARBON AND NITROGEN DYNAMICS IN SOILS AFTER REPEATED MANURE APPLICATIONS: MEASUREMENTS AND MECHANISTIC SIMULATIONS." Doctoral thesis, Università degli Studi di Milano, 2011. http://hdl.handle.net/2434/152898.
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The first part of this Ph. D. Thesis (Chapters 1 and 2) is relative to the calibration of a soil organic matter simulation model (the CN-SIM model) by applying it to an experimental data-set, using two different methodologies, in order to verify its conceptual structure and obtaining parameters to describe the partitioning of C and N within the manures. Based on the optimization results, it emerged that the low model performance could be attributed to the lack of some processes involving mineral nitrogen transformations into the soil. In order to better understand the nitrogen dynamics following manure application to the soil, an incubation experiment was build up. In the experiment, two different manures were applied to two soils of different texture, and, in order to estimate the contribution of manure recalcitrant fractions to the mineralization dynamics of C and N in the soil (residual effect of added manure carbon and nitrogen), each manure was applied four times on the same soil (Chapter 3). In the incubation experiment were included measurements of non-exchangeable ammonium, with the aim of better understand if the lower recoveries of added manure ammonium, often found on the clay soils, were due to microbial biomass immobilization or ammonium clay-fixation. Measurements obtained in the incubation experiment were the used to perform a preliminary modification of the CN-SIM model to take into account the ammonium fixation and release processes (Charter 4).
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Kreier, Daniel. "Ultrafast single-electron diffraction at 100 keV and investigation of carbon-nanotube dynamics." Diss., Ludwig-Maximilians-Universität München, 2015. http://nbn-resolving.de/urn:nbn:de:bvb:19-183901.
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Time-resolved electron diffraction is a powerful tool to observe ultrafast structural dynamics in materials and molecules with atomic spatial as well as temporal resolution. Due to Coulomb repulsion, however, the use of only single-electrons or few-electrons per pulse is inevitable to reach the shortest pulse durations. Electrons have rather high scattering cross sections and thus experiments in transmission require ultrathin samples in the nanometer-range, making sample preparation very challenging. Up to now, ultrafast single-electron diffraction was only demonstrated at an electron energy of 30 keV; these measurements were performed in our group at the “UED1-beamline”.
This work introduces our second-generation beamline, “UED2”, where the electron
acceleration voltage is upgraded from 30 to 100 kV, which allows the investigation of significantly thicker samples. This is decisively widening the range of complex materials that can be studied. In the experiment, electron pulses are generated by a two-photon photoemission process and the long-term stability of the source is shown. The samples can be placed in transmission as well as grazing-incidence geometry. To achieve phase-matching between the optical and electron
pulses, tilted optical pulses can be applied. We figured out that to avoid temporal distortions in tilted pulses, a geometry must be chosen in which the propagation direction of the tilted pulses is perpendicular to the grating’s surface. Furthermore, temporal distortions for ultrashort electron pulses caused by misaligned magnetic lenses are examined. It is found that a displacement or tilt of the lens causes significant temporal aberrations on a femtosecond time scale and pulse-lengthening is only minimized if the beam travels precisely on the symmetry axis. An experimental procedure detailed here for aligning lens-position and -tilt reduces the aberrations to less than one femtosecond.
For the “UED2-beamline”, a new laboratory was established and a first time-resolved electron diffraction experiment at this beamline performed. Anisotropic ultrafast atomic motion in carbon-nanotubes was observed, revealing the nature of the system’s chemical bonds, which vary from relatively weak van der Waals to strong covalent interactions.
In summary, it is thus shown that ultrafast electron diffraction at 100 keV with single/few electrons per pulse is an excellent method to study ultrafast atomic-scale dynamics even in complex solid samples with the highest possible resolution in space and time.Zeitaufgelöste Elektronenbeugung ist ein mächtiges Werkzeug, um ultraschnelle strukturelle Dynamik in Materialien und Molekülen sowohl mit atomarer räumlicher als auch zeitlicher Auflösung zu beobachten. Wegen der Coulombabstoßung ist allerdings die Verwendung von nur einem Elektron, oder wenigen Elektronen, pro Puls notwendig, um die kürzesten Pulsdauern zu erreichen. Elektronen haben recht hohe Streuquerschnitte und deshalb braucht man für Experimente in Transmission sehr dünne Proben, die nur wenige Nanometer dick sind; dies verursacht große Schwierigkeiten bei der Probenherstellung. Bisher wurden ultraschnelle Einzel-Elektronen-Beugungsexperimente nur bei einer Elektronenenergie von 30 keV gezeigt; diese Messungen wurden in unserer Gruppe an der „UED1-Beamline“ durchgeführt. Diese Arbeit stellt unsere Zweite-Generation-Beamline, „UED2“, vor. Die Beschleunigungsspannung der Elektronen wurde hierbei von 30 auf 100 kV erhöht, was die Untersuchung signifikant dickerer Proben ermöglicht. Im Experiment werden Elektronenpulse durch einen Zweiphotonen-Photoprozess erzeugt und die langfristige Stabilität der Quelle wird gezeigt. Die Proben kann man sowohl in Transmission als auch im streifenden Elektronen-Einfall (grazing-incidence) platzieren und um Phase-Matching zwischen den optischen und Elektronenpulsen zu erreichen, können verkippte optische Pulse verwendet werden. Um zeitliche Verzerrungen (Distorsionen) in den verkippten Pulsen zu vermeiden, muss die Geometrie für deren Erzeugung so gewählt werden, dass die Ausbreitungsrichtung der verkippten Pulse senkrecht zur Gitteroberfläche ist. Dass und wie dies möglich ist, wird hier gezeigt. Außerdem werden zeitliche Distorsionen in ultrakurzen Elektronenpulsen, die durch schlecht justierte Magnetlinsen verursacht werden, untersucht. Es zeigt sich, dass eine Verschiebung oder Verkippung der Magnetlinse zu signifikanten zeitlichen Aberrationen im Femtosekundenbereich führt und diese Pulsverlängerungen nur minimiert werden können, wenn der Strahl genau auf der Symmetrieachse der Linse liegt. Ein hier experimentell gezeigtes Verfahren zum Ausrichten von Linsen-Position und Neigung verringert die Aberrationen auf weniger als eine Femtosekunde. Für die „UED2-Beamline“ wurde ein neues Labor eingerichtet und ein erstes zeitaufgelöstes Elektronenbeugungs-Experiment an dieser Beamline durchgeführt. Eine anisotrope Bewegung der Atome in Kohlenstoff-Nanoröhrchen wurde beobachtet, welche die Natur der chemischen Bindungen in diesem System widerspiegelt, die zwischen relativen schwachen van der Waals und starken kovalenten Wechselwirkungen variiert. Insgesamt ist damit gezeigt, dass ultraschnelle zeitaufgelöste Elektronenbeugung bei 100 keV mit einzelnen/wenigen Elektronen pro Puls eine hervorragende Methode darstellt, ultraschnelle atomare Dynamik auch in komplexen Festkörperproben mit höchstmöglicher Auflösung in Raum und Zeit untersuchen zu können.
Books on the topic "Non Cartan dynamics"
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Let's Talk about Constitutions. International Institute for Democracy and Electoral Assistance, 2021. http://dx.doi.org/10.31752/idea.2021.73.
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Let’s talk about constitutions! is designed to present difficult constitutional concepts to non-specialist and young audiences in an entertaining and informative way. It has been developed to promote young people’s understanding of constitutional issues and thereby empower and inspire youth to play a full and meaningful part in their own constitution-building process. With dynamic images, relatable characters and simple language, Let’s talk about constitutions! illustrates key concepts to answer the questions: what is a constitution and why is it important? The cartoon is an educational tool that can be enjoyed by youth and adults alike, whether integrated into youth centre curricula or non-governmental organizations civic education campaigns. The booklet is designed primarily for Myanmar and the characters and scripts are tailored to this context. The information shared in the cartoon, however, is relevant for people interested in learning and teaching about constitutions all around the world.
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Lally, Jagjeet. India and the Silk Roads. Oxford University Press, 2021. http://dx.doi.org/10.1093/oso/9780197581070.001.0001.
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India and the Silk Roads is a global history of a continental interior, the first to comprehensively examine the textual and material traces of India’s caravan trade with central Asia. But what was the fate of these overland connections in the ages of sail and steam? This book brings the world of caravan trade to life—a world of merchants, mercenaries, pastoralists and pilgrims, but also of kings, bureaucrats and their subjects in the countryside and towns. Their livelihoods did not become obsolete with the advent of ‘modern’ technologies and the consequent emergence of new global networks. Terrestrial routes remained critically important, not only handling flows of goods and money, but also fostering networks of trade in credit, secret intelligence and fighting power. With the waning of the Mughal Empire during the eighteenth century, new Indian kingdoms and their rulers came to the fore, drawing their power and prosperity from resources brought by caravan trade. The encroachment of British and Russian imperialism into this commercial arena in the nineteenth century gave new significance to some people and flows, while steadily undermining others. By showing how no single ruler could control the nebulous yet durable networks of this trading world, which had its own internal dynamics even as it evolved in step with global transformations, this book forces us to rethink the history of globalisation and re-evaluate our fixation with empires and states as the building blocks of historical analysis.
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Knox-Hayes, Janelle. Carbon Markets: Resource Governance and Sustainable Valuation. Edited by Gordon L. Clark, Maryann P. Feldman, Meric S. Gertler, and Dariusz Wójcik. Oxford University Press, 2018. http://dx.doi.org/10.1093/oxfordhb/9780198755609.013.31.
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Carbon markets open several important avenues of inquiry into resource governance designed to address problems like climate change. The discipline of economic geography is well situated to add insight. This chapter examines the underlying assumptions behind market-based governance, particularly the emphasis on controlling greenhouse gases through pricing. The pricing of externalities alone does not guarantee the material changes in energy use now in the future that are required to combat climate change. A new framework for consideration of the spatial and temporal dynamics of value is proposed. A renewed focus on use value and its spatial characteristics could lend considerable insight to the understanding of industry, market creation, and resource governance. For example, entraining the temporal production of instruments of exchange to their sources of production and creating property rights to manage natural resources as service stocks rather than commodities could better generate external value.
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Christoforidis, Michael, and Elizabeth Kertesz. Carmen and the Staging of Spain. Oxford University Press, 2018. http://dx.doi.org/10.1093/oso/9780195384567.001.0001.
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Carmen and the Staging of Spain explores the Belle Époque fascination with Spanish entertainment that refashioned Bizet’s opera and gave rise to an international “Carmen industry.” Authors Michael Christoforidis and Elizabeth Kertesz challenge the notion of Carmen as an unchanging exotic construct, tracing the ways in which performers and productions responded to evolving fashions for Spanish style from its 1875 premiere to 1915. Focusing on selected realizations of the opera in Paris, London, and New York, Christoforidis and Kertesz explore the cycles of influence between the opera and its parodies; adaptations in spoken drama, ballet and film; and the panorama of flamenco, Spanish dance, and musical entertainments. Their findings also uncover Carmen's dynamic interaction with issues of Hispanic identity against the backdrop of Spain's changing international fortunes. The Spanish response to this now most-Spanish of operas is illuminated by its early reception in Madrid and Barcelona, adaptations to local theatrical genres, and impact on Spanish composers of the time. A series of Spanish Carmens, from opera singers Elena Sanz and Maria Gay to the infamous music-hall star La Belle Otero, had a crucial influence on the interpretation of the title role. Their stories provide a fresh context for the book's reappraisal of leading Carmens of the era, including Emma Calvé and Geraldine Farrar.
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Taylor, Peter, Geoff O'Brien, and Phil O'Keefe. Cities Demanding the Earth. Policy Press, 2020. http://dx.doi.org/10.1332/policypress/9781529210477.001.0001.
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Current climate change policy is necessary but insufficient. This is because the basic modus operandi – presenting scientific evidence to states for them to take action - misrepresents the complex process of anthropogenic climate change. The ‘anthropo’ bit is neglected in a misconceived supply-side (carbon) interpretation. The key question is, why is there so much demand for this carbon in the first place? This book introduces a demand-side interpretation bringing cities to the fore as central players in both generating climate changes and for finding solutions. Jane Jacobs’ urban analysis is combined with William F. Ruddiman’s historical tracing of greenhouse gases to provide a new understanding and narrative of anthropogenic climate change. The conclusion is that we are locked into a path to terminal consumption, which is accelerating as a consequence of Chinese urban growth, historically unprecedented in its sheer scale. To counter this we need to harness the power of cities in new ways, to steer urban demand away from its current destructive path. This is nothing less than re-inventing the city: not mitigation (the resilient city, necessary but not sufficient), not adaptation (sustainable city, also necessary but not sufficient) but stewardship, a process of dynamic stability creating the posterity city in sync with nature.
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Kayizzi-Mugerwa, Steve. Uganda’s nascent oil sector: Revenue generation, investor-stakeholder alignment, and public policy. UNU-WIDER, 2020. http://dx.doi.org/10.35188/unu-wider/2020/932-7.
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This paper discusses the political economy of oil in Uganda since the announcement of its discovery in 2006. It focuses on the dynamics of oil revenue generation (pre-commercial production) and expenditure, investor-stakeholder contestation (i.e. between bureaucrats, investors/oil companies, and domestic stakeholders), and the role of public policy. Although the Government has created several institutional and regulatory frameworks to manage oil-related revenues and ensure that oil contributes to structural transformation, Uganda is already experiencing many of the stylized facts associated with natural resource exploitation, including macroeconomic instability, rent dissipation, and, more broadly, threats of adverse impact on the environment and on local livelihoods in the oil regions. Besides these, Uganda, and similarly endowed African countries, face the economic challenges related to the global shift in recent decades towards a low-carbon development paradigm and the threatening prospect of oil investments becoming ‘stranded assets’. The latter issues are not yet part of the policy conversation in Uganda.
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Coss, Peter. The Aristocracy in England and Tuscany, 1000 - 1250. Oxford University Press, 2019. http://dx.doi.org/10.1093/oso/9780198846963.001.0001.
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Part I of this book is an in-depth examination of the characteristics of the Tuscan aristocracy across the first two and a half centuries of the second millennium, as studied by Italian historians and others working within the Italian tradition: their origins, interests, strategies for survival and exercise of power; the structure and the several levels of aristocracy and how these interrelated; the internal dynamics and perceptions that governed aristocratic life; and the relationship to non-aristocratic sectors of society. It will look at how aristocratic society changed across this period and how far changes were internally generated as opposed to responses from external stimuli. The relationship between the aristocracy and public authority will also be examined. Part II of the book deals with England. The aim here is not a comparative study but to bring insights drawn from Tuscan history and Tuscan historiography into play in understanding the evolution of English society from around the year 1000 to around 1250. This part of the book draws on the breadth of English historiography but is also guided by the Italian experience. The book challenges the interpretative framework within which much English history of this period tends to be written—that is to say the grand narrative which revolves around Magna Carta and English exceptionalism—and seeks to avoid dangers of teleology, of idealism, and of essentialism. By offering a study of the aristocracy across a wide time-frame and with themes drawn from Italian historiography, I hope to obviate these tendencies and to appreciate the aristocracy firmly within its own contexts.
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Humphreys, John, and Sally Little, eds. Challenges in Estuarine and Coastal Science. Pelagic Publishing, 2022. http://dx.doi.org/10.53061/bdix4458.
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Estuarine and coastal waters are acknowledged centres for anthropogenic impacts. Superimposed on the complex natural interactions between land, rivers and sea are the myriad consequences of human activity – a spectrum ranging from locally polluting effluents to some of the severest consequences of global climate change. For practitioners, academics and students in the field of coastal science and policy, this book examines and exemplifies current and future challenges: from upper estuaries to open coasts and adjacent seas; from tropical to temperate latitudes; from Europe to Australia. This authoritative volume marks the 50th anniversary of the Estuarine and Coastal Sciences Association, and contains a prologue by founding member Professor Richard Barnes and a short history of the Association. Individual chapters then address coastal erosion and deposition; open shores to estuaries and deltas; marine plastics; coastal squeeze and habitat loss; tidal freshwaters – saline incursion and estuarine squeeze; restoration management using remote data collection; carbon storage; species distribution and non-natives; shorebirds; Modelling environmental change; physical processes such as sediments and modelling; sea level rise and estuarine tidal dynamics; estuaries as fish nurseries; policy versus reality in coastal conservation; developments in Estuarine, coastal and marine management.
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Masters, Ben. Novel Style. Oxford University Press, 2017. http://dx.doi.org/10.1093/oso/9780198766148.001.0001.
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Re-examining elaborate English stylists from the post-war period to the present day (including Anthony Burgess, Angela Carter, Martin Amis, Zadie Smith, Nicola Barker, and David Mitchell) through a fresh style of ethical criticism that does not over-rely on notions of character and interiority (the terrain of the ‘humanist revival’), and that returns the author to centre-stage (contra the approach of the ‘new ethics’, with its indebtedness to poststructuralism), Novel Style defends the stylistic excesses of writers who were conscious of both writing out of excessive times and of the need for new kinds of artistic response to contemporary ethical pressures. Through its methodology, Novel Style calls for a return to close reading and aesthetic evaluation and recovers its subjects from theoretical quagmires by repositioning them as stylists and ethicists, arguing that the two positions are inextricable. For example, it considers how forms of stylistic excess—ranging from puns and wordplay to long sentences, proliferating imagery, repetitions, idiosyncratic rhythms, multiple levels of narration, and variable points of view—might enact ethically-charged dynamics like curiosity, particularity, complexity, and empathy. As well as being an impassioned defence of literary excess, flamboyance, and close reading, Novel Style asks fundamental questions about how novels think, see, and feel, and how they might change us.
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Clarke, Andrew. Water. Oxford University Press, 2017. http://dx.doi.org/10.1093/oso/9780199551668.003.0005.
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Liquid water is essential for life, and a metabolically active cell is ~70% water. The physical properties of liquid water, and their temperature dependence, are dictated to a significant extent by the properties of hydrogen bonds. From an ecological perspective, the important properties of liquid water include its high latent heats of fusion and vapourisation, its high specific heat, the ionisation, low dynamic viscosity and high surface tension. The solubility in water of oxygen, carbon dioxide and the calcium carbonate used to build skeletons in many invertebrates groups all increase with decreasing temperature. The hydrophobic interaction is important in the formation of cellular membranes and the folding of proteins; its strength increases with temperature, which may be a factor in the cold-denaturation of cellular macromolecules. The cell is extremely crowded with macromolecules. Coupled with the highly structured water close to membranes or protein surfaces and the hydration shells around ions, this means that the behaviour of water in cells is different from that of bulk water. The thermal behaviour of isolated cellular components studied in dilute aqueous buffers many not reflect accurately their behaviour in the intact cell or tissue.
Book chapters on the topic "Non Cartan dynamics"
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Zimmermann, Jörg, and Floyd E. Romesberg. "Carbon–Deuterium Bonds as Non-perturbative Infrared Probes of Protein Dynamics, Electrostatics, Heterogeneity, and Folding." In Protein Dynamics, 101–19. Totowa, NJ: Humana Press, 2013. http://dx.doi.org/10.1007/978-1-62703-658-0_6.
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Olofsson, Pontus, Curtis E. Woodcock, Alessandro Baccini, Richard A. Houghton, Mutlu Ozdogan, Vladimir Gancz, Viorel Blujdea, Paata Torchinava, Aydin Tufekcioglu, and Emin Zeki Baskent. "The Effects of Land Use Change on Terrestrial Carbon Dynamics in the Black Sea Region." In Regional Aspects of Climate-Terrestrial-Hydrologic Interactions in Non-boreal Eastern Europe, 175–82. Dordrecht: Springer Netherlands, 2009. http://dx.doi.org/10.1007/978-90-481-2283-7_19.
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Qi, Jianhui. "Development and Validation of a Riemann Solver in OpenFOAM for Non-ideal Compressible Fluid Dynamics." In Simulation Tools and Methods for Supercritical Carbon Dioxide Radial Inflow Turbine, 129–59. Singapore: Springer Nature Singapore, 2022. http://dx.doi.org/10.1007/978-981-19-2860-4_5.
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Manzoni, Cristian, Alessio Gambetta, Giulio Cerullo, Guglielmo Lanzani, Enzo Menna, Moreno Meneghetti, Sergei Tretiak, et al. "Real time observation of non-linear coherent phonon dynamics in semiconducting single wall carbon nanotubes." In Ultrafast Phenomena XV, 695–97. Berlin, Heidelberg: Springer Berlin Heidelberg, 2007. http://dx.doi.org/10.1007/978-3-540-68781-8_223.
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Husain, Mushahid, and Ayub Khan. "Nanotechnology and Mathematics “Study of Non-linear Dynamic Vibration in Single Walled Carbon Nanotubes (SWNTs)”." In Mathematical Models, Methods and Applications, 137–41. Singapore: Springer Singapore, 2015. http://dx.doi.org/10.1007/978-981-287-973-8_9.
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Petruccelli, Giuseppe, Antti Uusitalo, Aki Grönman, Teemu Turunen-Saaresti, and Marta Zocca. "Design of a Closed-Loop Supercritical Carbon Dioxide Wind Tunnel: Numerical Modelling of Non-equilibrium Condensation in a Converging-Diverging Nozzle." In Proceedings of the 3rd International Seminar on Non-Ideal Compressible Fluid Dynamics for Propulsion and Power, 103–13. Cham: Springer International Publishing, 2021. http://dx.doi.org/10.1007/978-3-030-69306-0_11.
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Carson, Dean B., Doris A. Carson, Per Axelsson, Peter Sköld, and Gabriella Sköld. "Disruptions and Diversions: The Demographic Consequences of Natural Disasters in Sparsely Populated Areas." In The Demography of Disasters, 81–99. Cham: Springer International Publishing, 2020. http://dx.doi.org/10.1007/978-3-030-49920-4_5.
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Abstract The Eight Ds model (Carson and Carson 2014) explains the unique characteristics of human and economic geography for sparsely populated areas (SPAs) as disconnected, discontinuous, diverse, detailed, dynamic, distant, dependent and delicate. According to the model, SPAs are subject to dramatic changes in demographic characteristics that result from both identifiable black swan events and less apparent tipping points in longer-term processes of demographic change (Carson et al. 2011). The conceptual foundations for this assertion are clear. Populations in SPAs can experience large and long-term impacts on the overall demographic structure as a result of decisions by a relatively small number of people. High levels of migration and mobility cause constant shifts in the demographic profile and prime SPAs to adapt to many different demographic states (Carson and Carson 2014). The Northern Territory of Australia, for example, experienced previously unseen waves of pre-retirement aged migrants in the past decade or so (Martel et al. 2013) as evidence of detailed but important changes to past trends. However, while dramatic demographic changes are conceptually possible and occasionally observable, there have been few attempts to examine the conditions under which such changes are likely to occur or not to occur. This is an important question particularly in relation to black swan events such as natural disasters because effective disaster management policy and planning is at least partially dependent on understanding who is affected and in what ways (Bird et al. 2013).
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Rathgeber, Cyrille B. K., Gonzalo Pérez-de-Lis, Laura Fernández-de-Uña, Patrick Fonti, Sergio Rossi, Kerstin Treydte, Arthur Gessler, Annie Deslauriers, Marina V. Fonti, and Stéphane Ponton. "Anatomical, Developmental and Physiological Bases of Tree-Ring Formation in Relation to Environmental Factors." In Stable Isotopes in Tree Rings, 61–99. Cham: Springer International Publishing, 2022. http://dx.doi.org/10.1007/978-3-030-92698-4_3.
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AbstractUnderstanding the process of wood formation and its dynamics over the growing season is fundamental to interpret the isotopic signature of tree rings. Indeed, the isotopic signal recorded in wood does not only depend on the conditions influencing carbon, water, and nitrogen uptake in the leaves and roots, but also on how these elements are translocated to the stem and incorporated into the developing xylem. Depending on environmental conditions, tree developmental stage, and physiological status, wood formation dynamics can vary greatly and produce tree-ring structures carrying specific isotopic signatures. In this chapter, we present the physiological processes involved in wood formation, along with their relationships with anatomical, developmental, and environmental factors, to understand when and how photosynthetic assimilates are progressively incorporated into the forming xylem, creating the final isotopic signature of a tree ring. First, we review current knowledge on the structure and functions of wood. Then we describe the xylogenesis process (how and when the new xylem cells produced by the cambium develop through successive differentiation phases), and its relationships with physiological, developmental, and environmental factors. Finally, we explain the kinetics of xylemcell differentiation and show why the knowledge recently acquired in this field allows us to better understand the isotopic signals in tree rings.
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Siegwolf, Rolf T. W., Martine M. Savard, Thorsten E. E. Grams, and Steve Voelker. "Impact of Increasing CO2, and Air Pollutants (NOx, SO2, O3) on the Stable Isotope Ratios in Tree Rings." In Stable Isotopes in Tree Rings, 675–710. Cham: Springer International Publishing, 2022. http://dx.doi.org/10.1007/978-3-030-92698-4_24.
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AbstractAnthropogenic activities such as industrialization, land use change and intensification of agriculture strongly contribute to changes in the concentrations of atmospheric trace gases. Carbon dioxide (CO2), oxidized N compounds(NOx), sulfur dioxide (SO2) and ozone(O3) have particularly significant impacts on plant physiology. CO2, the substrate for plant photosynthesis, is in the focus of interest as the ambiguous effect of its increasing concentration is controversially discussed. Is its increase beneficial for plants or are plants non-responsive? NOx, a product of combustion and lightning, can have either fertilizing or toxic effects depending on the concentration and form. This is also the case for reduced forms of nitrogen(NHy), which are mostly emitted from agricultural and industrial activities. In combination CO2and N compounds can have a fertilizing effect. SO2 and ground-level O3 are mostly phytotoxic, depending on their concentrations, daily and seasonal exposure dynamics, and tree health condition. Elevated concentrations of both substances arise from industrial combustion processes and car emissions. All of the above-mentioned gaseous compounds affect plant metabolism in their specific ways and to different degrees. This impacts the isotope fractionation leaving specific fingerprints in the C, O, (H) and N isotope ratios of organic matter. In this chapter we will show how the impact of increasing CO2 and air pollutants are reflected in the isotopic ratios of tree rings. Increasing CO2 shows a considerable variation in responses of δ13C and to a minor degree in δ18O. Ozone and SO2 exposure cause an overall increase of the δ13C values in tree rings and a slight decrease in δ18O, mimicking an increase in net photosynthesis (AN) and to a minor degree in stomatal conductance (gs). However, directly measured AN and gs values show the opposite, which does not always correspond with the isotope derived gas exchange data. NO2 concentration as it is found near highly frequented freeways or industrial plants causes an increase of δ13C while δ18O decreases. This indicates an increase in both AN and gs, which corresponds well with directly measured gas exchange data. Thus the air quality situation must be taken in consideration for the interpretation of isotope values in tree rings.
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Arabsolgar, Dena, and Andrea Musumeci. "Cloud-Based Platform for the Circular Value-Chain." In Systemic Circular Economy Solutions for Fiber Reinforced Composites, 271–302. Cham: Springer International Publishing, 2022. http://dx.doi.org/10.1007/978-3-031-22352-5_14.
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AbstractThe FiberEUse IT platform is a tool that enables the exchange of information among stakeholders working into and crossing the glass and carbon fibers value chains. The list of stakeholders had been identified and is listed into the document. The list of users of the platform is also listed into the document, although it is not fixed. During the collection and analysis of the requirements, the circularity of the approach had been in the core focus. This drove to the identification of solutions able to cover all the different and innovative aspects of a Circular Economy Systemic Innovation. New products, new processes, new materials, new connections, quick and unexpected introductions of innovations, methodological approach, end of waste concept, availability of objects for dismantle, not-standardized parameters, are only some of the aspects arisen analysing deeply the requirements. They have all been approached in the platform which is by definition circular, dynamic, expandable and polymorphic. In the FiberEUse project, the validation activities of the IT platform had adopted an agile approach involving demonstrators during the preliminary phases of analysis, and mock-up creation. An internal technical validation had been completed. The methodology had been adopted and main results are reported in Sect. 5.
Conference papers on the topic "Non Cartan dynamics"
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Sopanen, Jussi, Lasse Laurila, and Markus Hirvonen. "Torsion Vibration Analysis of a Cardan Shaft Driven by a Permanent Magnet Electric Motor." In ASME 2005 International Design Engineering Technical Conferences and Computers and Information in Engineering Conference. ASMEDC, 2005. http://dx.doi.org/10.1115/detc2005-84825.
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An analytical model of a double cardan shaft driveline is presented. The model has been derived by using a Lagrangian dynamics formulation and it includes description of the torsion flexibility of the shafts. The cardan shaft model is used in a coupled simulation with a direct torque controlled permanent magnet synchronous motor. Mechanical and electrical non-idealities affecting the dynamics of the driveline are studied. The modeled non-idealities include unequal joint angles, incorrect phasing of the cardan joints and current measurement errors in the supply of the electric motor. The results show that the control system of the electric drive tries to correct the transmission error caused by the mechanical non-idealities. This in turn leads to fluctuating torque and undesirable dynamic loads.
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Cannon, James, and Ortwin Hess. "Non-Equilibrium Studies of Molecular Flow Through Carbon Nanotubes." In ASME 2008 6th International Conference on Nanochannels, Microchannels, and Minichannels. ASMEDC, 2008. http://dx.doi.org/10.1115/icnmm2008-62265.
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Carbon nanotubes are likely to form an integral part of future nano-fluidic devices. In order to realise such devices, an understanding of the dynamics of molecular flow through nanotubes is crucial. We have conducted continuous-flow non-equilibrium molecular dynamics simulations of argon and hydrogen flow through nanotubes, in order to decipher the fundamental driving forces behind the flow dynamics, upon which the motions of more complex molecules are based. We detail the fundamental mechanisms of flow in the nano-confined space of a carbon nanotube, and demonstrate how this knowledge can be utilised to control the flow-rate and even convert from smooth to pulsed flow.
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Frankland, Sarah-Jane, Tozer Bandorawalla, and Thomas Gates. "Calculation of Non-bonded Forces due to Sliding of Bundled Carbon Nanotubes." In 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/10.2514/6.2003-1536.
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West, Stephen T., Charles White, Chris Celestino, Stuart Philpott, and Mark Pankow. "Design and Testing of Deployable Carbon Fiber Booms for CubeSat Non-Gossamer Applications." In 56th AIAA/ASCE/AHS/ASC Structures, Structural Dynamics, and Materials Conference. Reston, Virginia: American Institute of Aeronautics and Astronautics, 2015. http://dx.doi.org/10.2514/6.2015-0206.
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Avila, Antonio F., Viviane C. Munhoz, Aline M. Oliveira, Nathalia C. Menezes, Suchilla G. Leao, and Camila F. Silva. "Non-covalent Functionalization of CNT and Graphene and Its Application to Hybrid Carbon/Epoxy Composites." In 57th AIAA/ASCE/AHS/ASC Structures, Structural Dynamics, and Materials Conference. Reston, Virginia: American Institute of Aeronautics and Astronautics, 2016. http://dx.doi.org/10.2514/6.2016-0154.
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Ziems, K. M., S. Severino, M. Reduzzi, A. Summers, H. W. Sun, Y. H. Chien, J. Biegert, and S. Gräfe. "Ultrafast non-adiabatic relaxation dynamics of furan theoretically addressed for tr-AttoXAFS." In International Conference on Ultrafast Phenomena. Washington, D.C.: Optica Publishing Group, 2022. http://dx.doi.org/10.1364/up.2022.w2b.7.
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We employ a multi-physics approach comprised of on-the-fly surface hopping and various quantum chemical methods to examine the ultrafast relaxation dynamics of furan induced by a strong-field excitation and measured by attosecond carbon K-edge spectroscopy.
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NAKARMI, SUSHAN, VANDANA YADAV, and V. U. UNNIKRISHNAN. "Thermal Conductivity of Carbon Nanotubes Based on Reverse Non-Equilibrium Molecular Dynamics-Size Effect." In American Society for Composites 2017. Lancaster, PA: DEStech Publications, Inc., 2017. http://dx.doi.org/10.12783/asc2017/15340.
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Nakarmi, Sushan, and V. U. Unnikrishnan. "Thermal Transport Properties and Interface Effects of Carbon Nanostructures." In ASME 2017 International Mechanical Engineering Congress and Exposition. American Society of Mechanical Engineers, 2017. http://dx.doi.org/10.1115/imece2017-72475.
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The variations in thermal conductivity of nanocomposites are found to depend not only the intrinsic properties of the fiber and matrix phases but also on the interfacial resistance of the reinforcing phase. As we go down the length scales, the interfacial thermal resistance due to size of the nanoparticle becomes significant. In order to address the effect of size (length and diameter) of nanotube on the thermal transport property of nanotube composites, thermal conductivity of different nanotube samples varying in length and diameter will be estimated first using molecular dynamic (MD) simulations with AIREBO potentials. This will be carried out using the ‘Heat-Bath’ method - non-equilibrium molecular dynamics (NEMD) approach. In the heat bath method, constant amount of heat is added to and removed from the hot and cold regions and the resulting temperature gradient is measured and the thermal conductivity is calculated using the Fourier Law. This will be followed by the study of interfacial thermal resistance of these nanostructures. These intrinsic properties are then used with continuum based mathematical formulations to study the effect of size of the nanoparticle on the overall thermal conductivity of the nanocomposite.
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Kuang, Youdi, and Baoling Huang. "A Non-equilibrium Molecular Dynamics Study of Thermal Transport in Functionalized Carbon Nanotube/Polymer Nanocomposites." In The 15th International Heat Transfer Conference. Connecticut: Begellhouse, 2014. http://dx.doi.org/10.1615/ihtc15.tpp.008835.
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Manzoni, C., A. Gambetta, G. Cerullo, G. Lanzani, E. Menna, and M. Meneghetti. "Real time observation of non-linear coherent phonon dynamics in semiconducting single wall carbon nanotubes." In International Conference on Ultrafast Phenomena. Washington, D.C.: OSA, 2006. http://dx.doi.org/10.1364/up.2006.wd2.
Full textReports on the topic "Non Cartan dynamics"
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Yılmaz, Fatih. Understanding the Dynamics of the Renewable Energy Transition: The Determinants and Future Projections Under Different Scenarios. King Abdullah Petroleum Studies and Research Center, May 2022. http://dx.doi.org/10.30573/ks--2021-dp25.
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The global energy system’s current structure has severe environmental consequences that necessitate an urgent transformation toward more sustainable alternatives. Besides many available mitigation actions, such as enhancing energy efficiency, deploying nuclear energy, switching fuels and adopting carbon capture technologies, renewable energy (RE) has been the most widely applied one in many countries, especially for the power sector. The average country-level share of non-hydroelectric renewable energy (NhRE) in power generation rose sixfold over the last two decades, from less than 1% in 2000 to roughly 6% in 2018. Despite its wide application, significant heterogeneity exists in the RE transition across countries.
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Schmidt, Mark. Dynamics and variability of POC burial in depocenters of the North Sea (Skagerrak), Cruise No. AL561, 2.08.2021 – 13.08.2021, Kiel – Kiel, APOC. GEOMAR Helmholtz Centre for Ocean Research Kiel, 2021. http://dx.doi.org/10.3289/cr_al561.
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The AL561 cruise was conducted in the framework of the project APOC (“Anthropogenic impacts on Particulate Organic Carbon cycling in the North Sea”). This collaborative project between GEOMAR, AWI, HEREON, UHH, and BUND is to understand how particulate organic carbon (POC) cycling contributes to carbon sequestration in the North Sea and how this ecosystem service is compromised and interlinked with global change and a range of human pressures include fisheries (pelagic fisheries, bottom trawling), resource extraction (sand mining), sediment management (dredging and disposal of dredged sediments) and eutrophication. The main aim of the sampling activity during AL561 cruise was to recover undisturbed sediment from high accumulation sites in the Skagerrak/Kattegat and to subsample sediment/porewater at high resolution in order to investigate sedimentation transport processes, origin of sediment/POC and mineralization processes over the last 100- 200 years. Moreover, the actual processes of sedimentation and POC degradation in the water column and benthic layer will be addressed by sampling with CTD and Lander devices. In total 9 hydroacoustic surveys (59 profiles), 4 Gravity Corer, 7 Multicorer, 3 Lander and 4 CTD stations were successfully conducted during the AL561 cruise. - (Alkor-Berichte ; AL561)
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Bar-Tal, Asher, Paul R. Bloom, Pinchas Fine, C. Edward Clapp, Aviva Hadas, Rodney T. Venterea, Dan Zohar, Dong Chen, and Jean-Alex Molina. Effects of soil properties and organic residues management on C sequestration and N losses. United States Department of Agriculture, August 2008. http://dx.doi.org/10.32747/2008.7587729.bard.
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Objectives - The overall objective of this proposal was to explore the effects of soil properties and management practices on C sequestration in soils and off-site losses of N.The specific objectives were: 1. to investigate and to quantify the effects of soil properties on C transformations that follow OW decomposition, C losses by gaseous emission, and its sequestration by organic and mineral components of the soil; 2. to investigate and to quantify the effects of soil properties on organic N mineralization and transformations in soil, its losses by leaching and gaseous emission; 3. to investigate and to quantify the effects of management practices and plants root activity and decomposition on C and N transformations; and 4. to upgrade the models NCSOIL and NCSWAP to include inorganic C and root exudation dynamics. The last objective has not been fulfilled due to difficulties in experimentally quantification of the effects of soil inorganic component on root exudation dynamics. Objective 4 was modified to explore the ability of NCSOIL to simulate organic matter decomposition and N transformations in non- and calcareous soils. Background - Rates of decomposition of organic plant residues or organic manures in soil determine the amount of carbon (C), which is mineralized and released as CO₂ versus the amount of C that is retained in soil organic matter (SOM). Decomposition rates also greatly influence the amount of nitrogen (N) which becomes available for plant uptake, is leached from the soil or lost as gaseous emission, versus that which is retained in SOM. Microbial decomposition of residues in soil is strongly influenced by soil management as well as soil chemical and physical properties and also by plant roots via the processes of mineral N uptake, respiration, exudation and decay.
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Taucher, Jan, and Markus Schartau. Report on parameterizing seasonal response patterns in primary- and net community production to ocean alkalinization. OceanNETs, November 2021. http://dx.doi.org/10.3289/oceannets_d5.2.
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We applied a 1-D plankton ecosystem-biogeochemical model to assess the impacts of ocean alkalinity enhancement (OAE) on seasonal changes in biogeochemistry and plankton dynamics. Depending on deployment scenarios, OAE should theoretically have variable effects on pH and seawater pCO2, which might in turn affect (a) plankton growth conditions and (b) the efficiency of carbon dioxide removal (CDR) via OAE. Thus, a major focus of our work is how different magnitudes and temporal frequencies of OAE might affect seasonal response patterns of net primary productivity (NPP), ecosystem functioning and biogeochemical cycling. With our study we aimed at identifying a parameterization of how magnitude and frequency of OAE affect net growth rates, so that these effects could be employed for Earth System Modell applications. So far we learned that a meaningful response parameterization has to resolve positive and negative anomalies that covary with temporal shifts. As to the intricacy of the response patterns, the derivation of such parameterization is work in progress. However, our study readily provides valuable insights to how OAE can alter plankton dynamics and biogeochemistry. Our modelling study first focuses at a local site where time series data are available (European Station for Time series in the Ocean Canary Islands ESTOC), including measurements of pH, concentrations of total alkalinity, dissolved inorganic carbon (DIC), chlorophyll-a and dissolved inorganic nitrogen (DIN). These observational data were made available by Andres Cianca (personal communication, PLOCAN, Spain), Melchor Gonzalez and Magdalena Santana Casiano (personal communication, Universidad de Las Palmas de Gran Canaria). The choice of this location was underpinned by the fact that the first OAE mesocosm experiment was conducted on the Canary Island Gran Canaria, which will facilitate synthesizing our modelling approach with experimental findings. For our simulations at the ESTOC site in the Subtropical North Atlantic we found distinct, non-linear responses of NPP to different temporal modes of alkalinity deployment. In particular, phytoplankton bloom patterns displayed pronounced temporal phase shifts and changes in their amplitude. Notably, our simulations suggest that OAE can have a slightly stimulating effect on NPP, which is however variable, depending on the magnitude of OAE and the temporal mode of alkalinity addition. Furthermore, we find that increasing alkalinity perturbations can lead to a shift in phytoplankton community composition (towards coccolithophores), which even persists after OAE has stopped. In terms of CDR, we found that a decrease in efficiency with increasing magnitude of alkalinity addition, as well as substantial differences related to the timing of addition. Altogether, our results suggest that annual OAE during the right season (i.e. physical and biological conditions), could be a reasonable compromise in terms of logistical feasibility, efficiency of CDR and side-effects on marine biota. With respect to transferability to global models, the complex, non-linear responses of biological processes to OAE identified in our simulations do not allow for simple parameterizations that can easily adapted. Dedicated future work is required to transfer the observed responses at small spatiotemporal scales to the coarser resolution of global models.
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Cai, Yongxia, Christopher M. Wade, Justin S. Baker, Jason P. H. Jones, Gregory S. Latta, Sara B. Ohrel, Shaun A. Ragnauth, and Jared R. Creason. Implications of alternative land conversion cost specifications on projected afforestation potential in the United States. RTI Press, November 2018. http://dx.doi.org/10.3768/rtipress.2018.op.0057.1811.
Full textAbstract:
The Forestry and Agriculture Sector Optimization Model with Greenhouse Gases (FASOMGHG) has historically relied on regional average costs of land conversion to simulate land use change across cropland, pasture, rangeland, and forestry. This assumption limits the accuracy of the land conversion estimates by not recognizing spatial heterogeneity in land quality and conversion costs. Using data from Nielsen et al. (2014), we obtained the afforestation cost per county, then estimated nonparametric regional marginal cost functions for land converting land to forestry. These afforestation costs were then incorporated into FASOMGHG. Three different assumptions for land moving into the forest sector were run; constant average conversion cost, static rising marginal costs and dynamic rising marginal cost, in order to assess the implications of alternative land conversion cost assumptions on key outcomes, such as projected forest area and cropland use, carbon sequestration, and forest product output.
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Minz, Dror, Eric Nelson, and Yitzhak Hadar. Ecology of seed-colonizing microbial communities: influence of soil and plant factors and implications for rhizosphere microbiology. United States Department of Agriculture, July 2008. http://dx.doi.org/10.32747/2008.7587728.bard.
Full textAbstract:
Original objectives: Our initial project objectives were to 1) Determine and compare the composition of seed-colonizing microbial communities on seeds, 2) Determine the dynamics of development of microbial communities on seeds, and 3) Determine and compare the composition of seed-colonizing microbial communities with the composition of those in the soil and rhizosphere of the plants. Revisions to objectives: Our initial work on this project was hampered by the presence of native Pythium species in the soils we were using (in the US), preventing us from getting accurate assessments of spermosphere microbial communities. In our initial work, we tried to get around this problem by focusing on water potentials that might reduce damage from native Pythium species. This also prompted some initial investigation of the oomycete communities associated seedlings in this soil. However, for this work to proceed in a way that would allow us to examine seed-colonizing communities on healthy plants, we needed to either physically treat soils or amend soils with composts to suppress damage from Pythium. In the end, we followed the compost amendment line of investigation, which took us away from our initial objectives, but led to interesting work focusing on seed-associated microbial communities and their functional significance to seed-infecting pathogens. Work done in Israel was using suppressive compost amended potting mix throughout the study and did not have such problems. Our work focused on the following objectives: 1) to determine whether different plant species support a microbial induced suppression of Pythium damping-off, 2) to determine whether compost microbes that colonize seeds during early stages of seed germination can adequately explain levels of damping-off suppression observed, 3) to characterize cucumber seed-colonizing microbial communities that give rise to the disease suppressive properties, 4) assess carbon competition between seed-colonizing microbes and Pythium sporangia as a means of explaining Pythium damping-off suppression. Background: Earlier work demonstrated that seed-colonizing microbes might explain Pythium suppression. Yet these seed-colonizing microbial communities have never been characterized and their functional significance to Pythium damping-off suppression is not known. Our work set out to confirm the disease suppressive properties of seed-colonizing microbes, to characterize communities, and begin to determine the mechanisms by which Pythium suppression occurs. Major Conclusions: Compost-induced suppression of Pythium damping-off of cucumber and wheat can be explained by the bacterial consortia colonizing seeds within 8 h of sowing. Suppression on pea was highly variable. Fungi and archaea play no role in disease suppression. Potentially significant bacterial taxa are those with affinities to Firmicutes, Actinobacteria, and Bacteroidetes. Current sequencing efforts are trying to resolve these taxa. Seed colonizing bacteria suppress Pythium by carbon competition, allowing sporangium germination by preventing the development of germ tubes. Presence of Pythium had a strong effect on microbial community on the seed.
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Banin, Amos, Joseph Stucki, and Joel Kostka. Redox Processes in Soils Irrigated with Reclaimed Sewage Effluents: Field Cycles and Basic Mechanism. United States Department of Agriculture, July 2004. http://dx.doi.org/10.32747/2004.7695870.bard.
Full textAbstract:
The overall objectives of the project were: (a) To measure and study in situ the effect of irrigation with reclaimed sewage effluents on redox processes and related chemical dynamics in soil profiles of agricultural fields. (b) To study under controlled conditions the kinetics and equilibrium states of selected processes that affect redox conditions in field soils or that are effected by them. Specifically, these include the effects on heavy metals sorption and desorption, and the effect on pesticide degradation. On the basis of the initial results from the field study, increased effort was devoted to clarifying and quantifying the effects of plants and water regime on the soil's redox potential while the study of heavy metals sorption was limited. The use of reclaimed sewage effluents as agricultural irrigation water is increasing at a significant rate. The relatively high levels of suspended and, especially, dissolved organic matter and nitrogen in effluents may affect the redox regime in field soils irrigated with them. In turn, the changes in redox regime may affect, among other parameters, the organic matter and nitrogen dynamics of the root zone and trace organic decomposition processes. Detailed data of the redox potential regime in field plots is lacking, and the detailed mechanisms of its control are obscure and not quantified. The study established the feasibility of long-term, non-disturbing monitoring of redox potential regime in field soils. This may enable to manage soil redox under conditions of continued inputs of wastewater. The importance of controlling the degree of wastewater treatment, particularly of adding ultrafiltration steps and/or tertiary treatment, may be assessed based on these and similar results. Low redox potential was measured in a field site (Site A, KibutzGivat Brenner), that has been irrigated with effluents for 30 years and was used for 15 years for continuous commercial sod production. A permanently reduced horizon (Time weighted averaged pe= 0.33±3.0) was found in this site at the 15 cm depth throughout the measurement period of 10 months. A drastic cultivation intervention, involving prolonged drying and deep plowing operations may be required to reclaim such soils. Site B, characterized by a loamy texture, irrigated with tap water for about 20 years was oxidized (Time weighted average pe=8.1±1.0) throughout the measurement period. Iron in the solid phases of the Givat Brenner soils is chemically-reduced by irrigation. Reduced Fe in these soils causes a change in reactivity toward the pesticide oxamyl, which has been determined to be both cytotoxic and genotoxic to mammalian cells. Reaction of oxamyl with reduced-Fe clay minerals dramatically decreases its cytotoxicity and genotoxicity to mammalian cells. Some other pesticides are affected in the same manner, whereas others are affected in the opposite direction (become more cyto- and genotoxic). Iron-reducing bacteria (FeRB) are abundant in the Givat Brenner soils. FeRB are capable of coupling the oxidation of small molecular weight carbon compounds (fermentation products) to the respiration of iron under anoxic conditions, such as those that occur under flooded soil conditions. FeRB from these soils utilize a variety of Fe forms, including Fe-containing clay minerals, as the sole electron acceptor. Daily cycles of the soil redox potential were discovered and documented in controlled-conditions lysimeter experiments. In the oxic range (pe=12-8) soil redox potential cycling is attributed to the effect of the daily temperature cycle on the equilibrium constant of the oxygenation reaction of H⁺ to form H₂O, and is observed under both effluent and freshwater irrigation. The presence of plants affects considerably the redox potential regime of soils. Redox potential cycling coupled to the irrigation cycles is observed when the soil becomes anoxic and the redox potential is controlled by the Fe(III)/Fe(II) redox couple. This is particularly seen when plants are grown. Re-oxidation of the soil after soil drying at the end of an irrigation cycle is affected to some degree by the water quality. Surprisingly, the results suggest that under certain conditions recovery is less pronounced in the freshwater irrigated soils.
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Snyder, Victor A., Dani Or, Amos Hadas, and S. Assouline. Characterization of Post-Tillage Soil Fragmentation and Rejoining Affecting Soil Pore Space Evolution and Transport Properties. United States Department of Agriculture, April 2002. http://dx.doi.org/10.32747/2002.7580670.bard.
Full textAbstract:
Tillage modifies soil structure, altering conditions for plant growth and transport processes through the soil. However, the resulting loose structure is unstable and susceptible to collapse due to aggregate fragmentation during wetting and drying cycles, and coalescense of moist aggregates by internal capillary forces and external compactive stresses. Presently, limited understanding of these complex processes often leads to consideration of the soil plow layer as a static porous medium. With the purpose of filling some of this knowledge gap, the objectives of this Project were to: 1) Identify and quantify the major factors causing breakdown of primary soil fragments produced by tillage into smaller secondary fragments; 2) Identify and quantify the. physical processes involved in the coalescence of primary and secondary fragments and surfaces of weakness; 3) Measure temporal changes in pore-size distributions and hydraulic properties of reconstructed aggregate beds as a function of specified initial conditions and wetting/drying events; and 4) Construct a process-based model of post-tillage changes in soil structural and hydraulic properties of the plow layer and validate it against field experiments. A dynamic theory of capillary-driven plastic deformation of adjoining aggregates was developed, where instantaneous rate of change in geometry of aggregates and inter-aggregate pores was related to current geometry of the solid-gas-liquid system and measured soil rheological functions. The theory and supporting data showed that consolidation of aggregate beds is largely an event-driven process, restricted to a fairly narrow range of soil water contents where capillary suction is great enough to generate coalescence but where soil mechanical strength is still low enough to allow plastic deforn1ation of aggregates. The theory was also used to explain effects of transient external loading on compaction of aggregate beds. A stochastic forInalism was developed for modeling soil pore space evolution, based on the Fokker Planck equation (FPE). Analytical solutions for the FPE were developed, with parameters which can be measured empirically or related to the mechanistic aggregate deformation model. Pre-existing results from field experiments were used to illustrate how the FPE formalism can be applied to field data. Fragmentation of soil clods after tillage was observed to be an event-driven (as opposed to continuous) process that occurred only during wetting, and only as clods approached the saturation point. The major mechanism of fragmentation of large aggregates seemed to be differential soil swelling behind the wetting front. Aggregate "explosion" due to air entrapment seemed limited to small aggregates wetted simultaneously over their entire surface. Breakdown of large aggregates from 11 clay soils during successive wetting and drying cycles produced fragment size distributions which differed primarily by a scale factor l (essentially equivalent to the Van Bavel mean weight diameter), so that evolution of fragment size distributions could be modeled in terms of changes in l. For a given number of wetting and drying cycles, l decreased systematically with increasing plasticity index. When air-dry soil clods were slightly weakened by a single wetting event, and then allowed to "age" for six weeks at constant high water content, drop-shatter resistance in aged relative to non-aged clods was found to increase in proportion to plasticity index. This seemed consistent with the rheological model, which predicts faster plastic coalescence around small voids and sharp cracks (with resulting soil strengthening) in soils with low resistance to plastic yield and flow. A new theory of crack growth in "idealized" elastoplastic materials was formulated, with potential application to soil fracture phenomena. The theory was preliminarily (and successfully) tested using carbon steel, a ductile material which closely approximates ideal elastoplastic behavior, and for which the necessary fracture data existed in the literature.