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  • 04.08. Volcanology  (7)
  • Analytical Chemistry and Spectroscopy  (3)
  • autonomous platform; DATE/TIME; EuroSea; Improving and Integrating European Ocean Observing and Forecasting Systems for Sustainable use of the Oceans; netCDF file; netCDF file (File Size); SAILDRONE; SAILDRONE Gen6 Explorer USV; SD_1079-track  (3)
  • elliptic functions  (3)
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  • 1
    Digitale Medien
    Digitale Medien
    Stochastic averaging using elliptic functions to study nonlinear stochastic systems (1993)
    Springer
    Nonlinear dynamics 4 (1993), S. 373-387 
    Details
    ISSN: 1573-269X
    Schlagwort(e): Stochastic averaging ; nonlinear systems ; elliptic functions ; probability density
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Mathematik
    Notizen: Abstract In this paper, a new scheme of stochastic averaging using elliptic functions is presented that approximates nonlinear dynamical systems with strong cubic nonlinearities in the presence of noise by a set of Itô differential equations. This is an extension of some recent results presented in deterministic dynamical systems. The second order nonlinear differential equation that is examined in this work can be expressed as % MathType!MTEF!2!1!+-% feaafiart1ev1aaatCvAUfeBSjuyZL2yd9gzLbvyNv2CaerbuLwBLn% hiov2DGi1BTfMBaeXatLxBI9gBaerbd9wDYLwzYbItLDharqqtubsr% 4rNCHbGeaGqiVu0Je9sqqrpepC0xbbL8F4rqqrFfpeea0xe9Lq-Jc9% vqaqpepm0xbba9pwe9Q8fs0-yqaqpepae9pg0FirpepeKkFr0xfr-x% fr-xb9adbaqaaeGaciGaaiaabeqaamaabaabaaGcbaWexLMBb50ujb% qeguuDJXwAKbacfiGaf8hEaGNbamaacqGHRaWkcaWGJbadcaaIXaGc% cqWF4baEcqGHRaWkcaWGJbadcaaIZaGccqWF4baEdaahaaWcbeqaai% aaiodaaaGccqGHRaWkcqaH1oqzcaWGMbGaaiikaiab-Hha4jaacYca% cqWFGaaicuWF4baEgaGaaiaacMcacqGHRaWkcqaH1oqzdaahaaWcbe% qaaiaaigdacaGGVaGaaGOmaaaaruWrL9MCNLwyaGGbcOGaa43zaiaa% cIcacqWF4baEcaGGSaGae8hiaaIaf8hEaGNbaiaacaGGSaGae8hiaa% IaeqOVdGNaaeikaiaadshacaqGPaGaaiykaiabg2da9iaaicdaaaa!645D!\[\ddot x + c1x + c3x^3 + \varepsilon f(x, \dot x) + \varepsilon ^{1/2} g(x, \dot x, \xi {\text{(}}t{\text{)}}) = 0\] where c 1 and c 3 are given constants, ξ(t) is stationary stochastic process with zero mean and ε≪1 is a small parameter. This method involves the laborious manipulation of Jacobian elliptic functions such as cn, dn and sn rather than the usual trigonometric functions. The use of a symbolic language such as Mathematica reduces the computational effort and allows us to express the results in a convenient form. The resulting equations are Markov approximations of amplitude and phase involving integrals of elliptic functions. Finally, this method was applied to study some standard second order systems.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00120672
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  • 2
    Digitale Medien
    Digitale Medien
    The Method of Averaging for Euler's Equations of Rigid Body Motion (1997)
    Springer
    Nonlinear dynamics 14 (1997), S. 295-308 
    Details
    ISSN: 1573-269X
    Schlagwort(e): Spacecraft attitude motion ; method of averaging ; elliptic functions
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Mathematik
    Notizen: Abstract We formulate the method of averaging for perturbations of Euler's equations of rotational motion. Euler's equations are three strongly nonlinear coupled differential equations that can be viewed as a three dimensional oscillator. The method of averaging is used to determine the long-term influence of perturbation terms on the motion by averaging about the nominal rigid body motion. The treatment is applicable to a large class of motions including precession with large nutation – it is not restricted to small motions about simple spins or nearly axi-symmetric bodies. Three examples are shown that demonstrate the accuracy of the method's predictions.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1023/A:1008215327247
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  • 3
    Digitale Medien
    Digitale Medien
    Chaos in a system with a periodically disappearing separatrix (1990)
    Springer
    Nonlinear dynamics 1 (1990), S. 401-420 
    Details
    ISSN: 1573-269X
    Schlagwort(e): Chaos ; perturbation methods ; elliptic functions ; differential equations
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Mathematik
    Notizen: Abstract We investigate the system $$\ddot x - x\cos \varepsilon 1 + x^3 = 0$$ in which ε≪1 by using averaging and elliptie functions. It is shown that this system is applicable to the dynamics of the familiar rotating-plane pendulum. The slow foreing permits us to envision an ‘instantancous phase portrait’ in the $$x - \dot x$$ phase plane which exhibits a center at the origin when cos ε1≤0 and a saddle and associated double homoclinic loop separatrix when cos ɛ 1 〉 0. The chaos in this problem is related to the question of on which side (left (=L) or right (=R)) of the reappearing double homoclinic loop separatrix a motion finds itself. We show that the sequence of L's and R's exhibits sensitive dependence on initial conditions by using a simplified model which assumes that motions cross the instantancous separatrix instantancously. We also present an improved model which ‘patches’ a separatrix boundary layer onto the averaging model. The predictions of both models are compared with the results of numerical integration.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF01893171
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  • 4
    Digitale Medien
    Digitale Medien
    Negative-ion fast atom bombardment mass spectrometry in the characterization of deoxyfluorinated sugars (1994)
    Chichester : Wiley-Blackwell
    Biological Mass Spectrometry 29 (1994), S. 553-555 
    Details
    ISSN: 0030-493X
    Schlagwort(e): Chemistry ; Analytical Chemistry and Spectroscopy
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Notizen: Negative-ion fast atom bombardment mass spectrometry and metastable ion studies were applied to the characterization of three isomeric fluorine-containing sugars. Peculiar fragmentation processes were evidenced for each isomer, enabling their differentiation. Comparison with the behaviour of a non-fluorinated analogue allowed investigation of the role of fluorine in the decomposition processes of these compounds.
    Zusätzliches Material: 2 Tab.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/oms.1210291007
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  • 5
    Digitale Medien
    Digitale Medien
    13C NMR investigation of some hetero-ring substituted 2- and 4-quinolone systems (1981)
    Chichester : Wiley-Blackwell
    Organic Magnetic Resonance 17 (1981), S. 242-245 
    Details
    ISSN: 0030-4921
    Schlagwort(e): Chemistry ; Analytical Chemistry and Spectroscopy
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Notizen: A series of 2- and 4-quinolones substituted in the hetero-ring have been evaluated using 13C NMR techniques. Substituent effects are discussed as an aid to evaluation of potential tautomerization in the 2-quinolone systems. The observed substituent shifts for systems having a hydroxy function at the 4-position in the 2-quinolones can be explained without implementing the tautomerism to a 4-quinolone.
    Zusätzliches Material: 5 Tab.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/mrc.1270170404
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  • 6
    Digitale Medien
    Digitale Medien
    Fast atom bombardment mass spectrometry of new polydentate schiff bases. 2. The case of mono- and bisaldimines containing pyridine groups (1994)
    Chichester : Wiley-Blackwell
    Biological Mass Spectrometry 29 (1994), S. 566-570 
    Details
    ISSN: 0030-493X
    Schlagwort(e): Chemistry ; Analytical Chemistry and Spectroscopy
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Notizen: The mass spectrometric behaviour of seven polydentate Schiff bases derived from the condensation of formyl or diformyl precursors (2,3-dihydroxy- or 2,5-dihydroxy-benzaldehyde, 3-metoxy- or 3-ethoxy-salicylaldehyde, 3-formyl-salicyclic acid, 4-methoxy- or 4-chloro-2,6-diformylphenol) with 2-aminomethylpyridine have been investigated by fast atom bombardment mass spectrometry and metastable ion studies.
    Zusätzliches Material: 2 Tab.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/oms.1210291010
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  • 7
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    Effusion Rate Evolution During Small‐Volume Basaltic Eruptions: Insights From Numerical Modeling (2020)
    Wiley Agu
    Details
    Publikationsdatum: 2020-10-16
    Beschreibung: The temporal evolution of effusion rate is the main controlling factor of lava spreading and emplacement conditions. Therefore, it represents the most relevant parameter for characterizing the dynamics of effusive eruptions and thus for assessing the volcanic hazard associated with this type of volcanism. Since the effusion rate curves can provide important insights into the properties of the magma feeding system, several efforts have been performed for their classification and interpretation. Here, a recently published numerical model is employed for studying the effects of magma source and feeding dike properties on the main characteristics (e.g., duration, erupted mass, and effusion rate trend) of small‐volume effusive eruptions, in the absence of syn‐eruptive magma injection from deeper storages. We show that the total erupted mass is mainly controlled by magma reservoir conditions (i.e., dimensions and overpressure) prior to the eruption, whereas conduit processes along with reservoir properties can significantly affect mean effusion rate, and thus, they dramatically influence eruption duration. Simulations reproduce a wide variety of effusion rate trends, whose occurrence is controlled by the complex competition between conduit enlargement and overpressure decrease due to magma withdrawal. These effusion rate curves were classified in four groups, which were associated with the different types described in the literature. Results agree with the traditional explanation of effusion rate curves and provide new insights for interpreting them, highlighting the importance of magma reservoir size, initial overpressure, and initial width of the feeding dike in controlling the nature of the resulting effusion rate curve.
    Beschreibung: Published
    Beschreibung: e2019JB01930
    Beschreibung: 5V. Processi eruttivi e post-eruttivi
    Beschreibung: JCR Journal
    Schlagwort(e): effusive eruption ; basaltic eruptions ; numerical modeling ; 04.08. Volcanology
    Repository-Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
    Materialart: article
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  • 8
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    The effects of environmental parameters on diffuse degassing at Stromboli volcano: Insights from joint monitoring of soil CO2 flux and radon activity (2019)
    Elsevier
    Details
    Publikationsdatum: 2021-06-30
    Beschreibung: Soil CO2 flux and 222Rn activity measurements may positively contribute to the geochemicalmonitoring of active volcanoes. The influence of several environmental parameters on the gas signals has been substantially demonstrated. Therefore, the implementation of tools capable of removing (or minimising) the contribution of the atmospheric effects from the acquired time series is a challenge in volcano surveillance. Here, we present 4 years-long continuousmonitoring (fromApril 2007 to September 2011) of radon activity and soil CO2 flux collected on the NE flank of Stromboli volcano. Both gases record higher emissions during fall–winter (up to 2700 Bq * m−3 for radon and 750 g m−2 day−1 for CO2) than during spring–summer seasons. Short-time variations on 222Rn activity aremodulated by changes in soil humidity (rainfall), and changes in soil CO2 flux that may be ascribed to variations in wind speed and direction. The spectral analyses reveal diurnal and semi-diurnal cycles on both gases, outlining that atmospheric variations are capable to modify the gas release rate fromthe soil. The long-termsoil CO2 flux shows a slow decreasing trend, not visible in 222Rn activity, suggesting a possible difference in the source depth of the of the gases, CO2 being deeper and likely related to degassing at depth of the magma batch involved in the February–April 2007 effusive eruption. To minimise the effect of the environmental parameters on the 222Rn concentrations and soil CO2 fluxes, two different statistical treatments were applied: the Multiple Linear Regression (MLR) and the Principal Component Regression (PCR). These approaches allow to quantify theweight of each environmental factor on the two gas species and showa strong influence of some parameters on the gas transfer processes through soils. The residual values of radon and CO2 flux, i.e. the values obtained after correction for the environmental influence, were then compared with the eruptive episodes that occurred at Stromboli during the analysed time span (2007–2011) but no clear correlations emerge between soil gas release and volcanic activity. This is probably due to i) the distal location of the monitoring stations with respect to the active craters and to ii) the fact that during the investigated period no major eruptive phenomena (paroxysmal explosion, flank eruption) occurred. Comparison of MLR and PCR methods in time-series analysis indicates thatMLR can bemore easily applied to real time data processing in monitoring of open conduit active volcanoes (like Stromboli) where the transition to an eruptive phase may occur in relatively short times.
    Beschreibung: This researchwas partly funded by ItalianMinistry of University and Research (MIUR) and by University of Torino-Fondazione Compagnia di San Paolo. Additional fundswere provided by the Italian “Presidenza del Consiglio dei Ministri–Dipartimento della Protezione Civile (DPC)” through the DEVnet Project (a cooperative program between the Departments of Earth Sciences of the University of Torino and the University of Florence) and through the “Potenziamento Monitoraggio Stromboli” project. Additional funds for improving our computing hardware were provided by Fondazione Cassa di Risparmio di Torino.
    Beschreibung: Published
    Beschreibung: 65-78
    Beschreibung: 4V. Processi pre-eruttivi
    Beschreibung: JCR Journal
    Schlagwort(e): Stromboli volcano ; Continuous geochemical monitoring ; Soil CO2 flux ; Radon activity ; Environmental parameters ; Time series analyses ; 04.08. Volcanology
    Repository-Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
    Materialart: article
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  • 9
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    Modeling lava flow propagation over a flat landscape by using MrLavaLoba: the case of the 2014–2015 eruption at Holuhraun, Iceland (2019)
    Details
    Publikationsdatum: 2020-03-05
    Beschreibung: During the emplacement of the 2014-2015 lava flow in Holuhraun (Iceland) a new code for the simulation of lava flows (MrLavaLoba) was developed and tested. MrLavaLoba is a probabilistic code which derives the area likely to be inundated and the thickness of the final lava deposit. The flow field in Holuhraun progressed through a fairly flat floodplain, and the initial limited availability of topographic data was challenging, forcing us to develop specific modeling strategies. The development of the code, as well as simulation tests, continued after the end of the eruption, and latest results largely benefitted from the availability of improved topographic data. MrLavaLoba simulations of the Holuhraun scenario are compared with detailed observational analyses derived from the literature. The obtained results highlight that small-scale morphological features in the preemplacement topography can strongly influence the propagation of the flow. The distribution of the volume settling throughout the extension of the flow field turned out to be very important, and strongly affects the fit between the simulated and the real extent of the flow field. The performed analysis suggests that an improvement in the code should allow adaptable calibration during the course of the eruption in order to mimic different emplacement styles in different phases.
    Beschreibung: Published
    Beschreibung: VO228
    Beschreibung: 5V. Processi eruttivi e post-eruttivi
    Beschreibung: JCR Journal
    Schlagwort(e): lava flow ; Holuhraun ; 04.08. Volcanology ; 05.01. Computational geophysics
    Repository-Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
    Materialart: article
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  • 10
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    Validation of an integrated satellite-data-driven response to an effusive crisis: the April–May 2018 eruption of Piton de la Fournaise (2020)
    INGV
    Details
    Publikationsdatum: 2020-06-17
    Beschreibung: Satellite‐based surveillance of volcanic hot spots and plumes can be coupled with modeling to allow ensemble‐based approaches to crisis response. We complete benchmark tests on an effusive crisis response protocol aimed at delivering product for use in tracking lava flows. The response involves integration of four models: MIROVA for discharge rate (TADR), the ASTER urgent response protocol for delivery of high‐spatial resolution satellite data, DOWNFLOW for flow path projections, and PyFLOWGO for flow run‐out. We test the protocol using the data feed available during Piton de la Fournaise’s April–May 2018 eruption, with product being delivered to the Observatoire du Piton de la Fournaise via Google Drive. The response was initialized by an alert at 19:50Z on 27 April 2018. Initially DOWNFLOW‐FLOWGO were run using TADRs typical of Piton de la Fournaise, and revealed that flow at 〉120 m 3 /s could reach the island belt road. The first TADR (10– 20 m 3 /s) was available at 09:55Z on 28 April, and gave flow run‐outs of 1180–2510 m. The latency between satellite overpass and TADR provision was 105 minutes, with the model result being posted 15 minutes later. An InSAR image pair was completed six hours after the eruption began, and gave a flow length of 1.8 km; validating the run‐out projection. Thereafter, run‐outs were updated with each new TADR, and checked against flow lengths reported from InSAR and ASTER mapping. In all, 35 TADRs and 15 InSAR image pairs were processed during the 35‐day‐long eruption, and 11 ASTER images were delivered.
    Beschreibung: Published
    Beschreibung: VO230
    Beschreibung: 5V. Processi eruttivi e post-eruttivi
    Beschreibung: JCR Journal
    Schlagwort(e): 04.08. Volcanology
    Repository-Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
    Materialart: article
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