Full Breakup Research Articles

Characterization and mapping of continental breakup and seafloor spreading initiation: The example of the northern rifted margin of the South China Sea

AbstractMapping ocean‐continent transitions (OCTs) separating equivocal continental and oceanic crusts is fundamental to investigate breakup processes and define the age and location of initial seafloor spreading. However, proposed limits of OCTs are rarely consistent, do not use uniform criteria, and result in conflicting interpretations as shown for the case of the northern South China Sea (SCS). We review original datasets including reflection and refraction seismic sections, drilling and potential field data with the aim to develop a ‘drilling‐constrained integrated geological‐geophysical’ approach to define the OCT along the northern SCS, understand the breakup process, and to compare the OCT in the SCS with those at Atlantic type rifted margins. The result shows a narrow, 5–15 km wide OCT. It separates a segmented margin that rifted a former arc in the west and a forearc in the east, both facing a Penrose oceanic crust that thins from the west towards the east. Seafloor spreading may have first nucleated at two centres during magnetic anomaly C11 in the NE and central subbasins, which then locally propagated both W and E to break through salients and produce full breakup at 29 Ma (anomaly C10r). Breakup at the SCS shows many differences to Atlantic type margins, in part due to inheritance but also due to rift/spreading‐related parameters such as strain/spreading rates.

Fragmentation of heated droplets of coal-water slurries containing petrochemicals

This research presents experimental findings on the fragmentation of droplets of coal-water slurries containing petrochemicals heated on a substrate (300–600 °C), in an air flow (450–550 °C), and in a tubular muffle furnace (500–700 °C). The fuels were composed of water, coal, coal processing waste (filter cakes), used industrial turbine oil, sawdust, nut shells, and stabilizers (neonol, starch, and tween). Before ignition, heated droplets behaved in three possible ways: gradual shrinking due to moisture evaporation; significant surface deformation when subjected to heating and droplet breakup with large fragments separating from it; full breakup of a droplet into small fragments. We recorded the droplet breakup delay times and integral characteristics of secondary fragments (number, size, and surface area) in comparison with the same parameters of the initial droplet. We also established the impact of a set of factors (temperature, heating scheme, and component composition of droplets) on the above characteristics. Approximations were obtained for the dependences established to be used for mathematical modeling. Finally, the findings were compared with the earlier established characteristics of similar processes studied in experiments with emulsion droplets and two-component immiscible droplets containing liquid combustible and noncombustible components.

Accelerating Taylor bubbles within circular capillary channels: Break-up mechanisms and regimes

In the present paper, an enhanced Volume of Fluid model is applied for the conduction of parametric numerical simulations, to investigate break-up phenomena of accelerating, elongated, vapour bubbles, within circular mini-channels. The effect of fundamental controlling parameters in the resulting break-up characteristics is investigated. Four different series of parametric numerical simulations of isolated vapour bubbles within mini-channels are performed, examining the effects of the imposed pressure difference between the inlet and the outlet of the channel, the surface tension, the effect of the applied heat flux as well as the initial liquid film thickness between the bubbles and the channel, on the developed vapour/liquid interface dynamics. The overall dimensionless number ranges examined are 6.76 < We < 1474.7, 0.007 < Ca < 0.14, 694 < Re < 12541 and by introducing a modified Froude number in order to account for the flow acceleration, 1 < Fr* < 21.86. These dimensionless number ranges are selected in order to overlap with experimental observations in zero-gravity Pulsating Heat Pipe experiments that constitute the motivation for the present numerical investigation. The proposed simulation results identify three prevailing regimes. A “full break-up” regime, a “partial break-up” regime and a “no break-up” regime. The entrainment of liquid droplets at the trailing edge of the vapour slugs is in most cases responsible for their subsequent “full break-up”, into a leading and a trailing bubble, as it is identified from the numerical simulations. Moreover, the applied heat flux does not influence the resulting break-up regimes. Finally, these identified break-up regimes, are grouped together into a well-defined flow map with respect to the We and Fr* numbers.

Conditions and characteristics of droplets breakup for industrial waste-derived fuel suspensions ignited in high-temperature air

This research is focused on the ignition and combustion mechanisms and characteristics of single droplets of seven different composite liquid fuels, based on wet coal processing waste (fine coal + 50 wt% of water) with 40 wt% of vegetable oils (castor, rapeseed) and used petroleum-based oils (lubricants – motor, compressor, and turbine oils; working fluid – hydraulic oil; insulating fluid – transformer oil). The combustion of waste-derived fuel suspensions is initiated by introducing single droplets into heated motionless air with a temperature of 700–1,000 °C. Threshold conditions (component composition, concentration of combustible liquid, and temperature) were detected, for which micro-explosions during the induction period resulted in the full breakup of droplets, combustion of products (vapors and fine particles) and their subsequent rapid burnout. A high-speed video recording system is used to establish consistent patterns of physical and chemical processes, as well as ignition and combustion characteristics (ignition delay times, burnout time, velocity of breakup products, and size of their burnout area) for a group of fuels under the conditions of droplet breakup. A hypothesis about how the composition of the component affects the breakup of droplets during ignition was formulated based on the results of analyzing the properties (initial boiling point and evaporation rates of oils, their surface tension and surface free energy, as well as wettability of dry coal processing waste) of separate fuel components.

Optimizing Aerosolization Using Computational Fluid Dynamics in a Pediatric Air-Jet Dry Powder Inhaler.

The objective of this study was to optimize the performance of a high-efficiency pediatric inhaler, referred to as the pediatric air-jet DPI, using computational fluid dynamics (CFD) simulations with supporting experimental analysis of aerosol formation. The pediatric air-jet DPI forms an internal flow pathway consisting of an inlet jet of high-speed air, capsule chamber containing a powder formulation, and outlet orifice. Instead of simulating full breakup of the powder bed to an aerosol in this complex flow system, which is computationally expensive, flow-field-based dispersion parameters were sought that correlated with experimentally determined aerosolization metrics. For the pediatric air-jet DPI configuration that was considered, mass median aerodynamic diameter (MMAD) directly correlated with input turbulent kinetic energy normalized by actuation pressure and flow kinetic energy. Emitted dose (ED) correlated best with input flow rate multiplied by the ratio of capillary diameters. Based on these dispersion parameters, an automated CFD process was used over multiple iterations of over 100 designs to identify optimal inlet and outlet capillary diameters, which affected system performance in complex and unexpected ways. Experimental verification of the optimized designs indicated an MMAD < 1.6μm and an ED > 90% of loaded dose. While extrathoracic depositional loss will be determined in future studies, at an operating flow rate of 15L/min, it is expected that pediatric mouth-throat or even nose-throat aerosol deposition fractions will be below 10% and potentially less than 5% representing a significant improvement in the delivery efficiency of dry powder pharmaceutical aerosols to children.

Energy evolution of channel coupling for the system Li6+Ni64 at near-barrier energies

Background: Different theoretical models have been used to understand the effects of coupling of direct reaction channels on reaction observables in recent years. However, very few attempts have been made to check the consistency of the model calculations in terms of comparing different experimental observables with the model predictions.Purpose: In the present work, coupled channel calculations are performed with transfer and breakup coupling for collision of the weakly bound stable projectile $^{6}\mathrm{Li}$ with the medium-mass target $^{64}\mathrm{Ni}$ at near-barrier energies. The main goal is to find the consistency of the model calculation in simultaneous reproduction of reaction observables like the elastic angular distributions, back-angle elastic excitation function, and fusion excitation function to find the effective energy regions of dominance of these couplings.Method: Both coupled reaction channel (CRC) and continuum discretized coupled channel (CDCC) calculations are performed using the code fresco. Transfer coupling is included through the CRC formalism. The CDCC scheme is used for breakup coupling and to distinguish the effect of resonant and nonresonant couplings.Results: In the case of the CRC calculation, the full coupling including inelastic scattering, $1n$ stripping, and $1p$ stripping gives the best description of the experimental data and particularly reproduces the data in the subbarrier energy region. It is observed that the $1p$-transfer channel has a larger impact on reaction observables compared to $1n$ transfer. On the other hand, for breakup nonresonant breakup has the dominant effect on the reaction observables, although resonant breakup has a larger cross section. The full breakup coupling reproduces the elastic scattering angular distributions and excitation function in the above-barrier region. But the scheme overpredicts these observables in the subbarrier region.Conclusion: CRC and CDCC calculations are complementary to each other. The energy dependencies of the relevant couplings for the $^{6}\mathrm{Li}+^{64}\mathrm{Ni}$ system around the barrier show that inelastic and transfer coupling are important at energies below the Coulomb barrier but continuum coupling is dominant in the above-barrier energy region.

Decarbonation in an intracratonic setting: Insight from petrological‐thermomechanical modeling

AbstractCratons form the stable core roots of the continental crust. Despite long‐term stability, cratons have failed in the past. Cratonic destruction (e.g., North Atlantic Craton) due to chemical rejuvenation at the base of the lithosphere remains poorly constrained numerically. We use 2‐D petrological‐thermomechanical models to assess cratonic rifting characteristics and mantle CO2 degassing in the presence of a carbonated subcontinental lithospheric mantle (SCLM). We test two tectonothermal SCLM compositions: Archon (depleted) and Tecton (fertilized) using 2 CO2 wt % in the bulk composition to represent a metasomatized SCLM. We parameterize cratonic breakup via extensional duration (7–12 Ma; full breakup), tectonothermal age, TMoho (300–600°C), and crustal rheology. The two compositions with metasomatized SCLMs share similar rifting features and decarbonation trends during initial extension. However, we show long‐term (&gt;67 Ma) stability differences due to lithospheric density contrasts between SCLM compositions. The Tecton model shows convective removal and thinning of the metasomatized SCLM during failed rifting. The Archon composition remained stable, highlighting the primary role for SCLM density even when metasomatized at its base. In the short‐term, three failed rifting characteristics emerge: failed rifting without decarbonation, failed rifting with decarbonation, and semifailed rifting with dry asthenospheric melting and decarbonation. Decarbonation trends were greatest in the failed rifts, reaching peak fluxes of 94 × 104 kg m−3. Increased TMoho did not alter the effects of rifting or decarbonation. Lastly, we show mantle regions where decarbonation, mantle melting in the presence of carbonate, and preservation of carbonated mantle occur during rifting.

Two-phase Cretaceous–Paleocene rifting in the Taranaki Basin region, New Zealand; implications for Gondwana break-up

The break-up of Gondwana resulted in extension of New Zealand continental crust during the Cretaceous–Paleocene. Offshore the geometry and rift history are well imaged by new regional mapping of a large seismic reflection dataset, tied to wells, used here to document the Cretaceous–Paleocene ( c . 105 – 55 Ma) evolution of the greater Taranaki Basin region. Two temporally distinct phases of rifting have been recognized in the region, and record Gondwana break-up. The first (Zealandia rift phase) produced half-grabens trending NW to WNW during the mid-Cretaceous ( c . 105 – 83 Ma). These rift basins predate, and are parallel to, Tasman Sea spreading centres. They record distributed stretching of northern Zealandia prior to the onset of seafloor spreading in the Tasman Sea. A short period ( c . 83 – 80 Ma) of uplift and erosion followed, possibly representing a break-up unconformity, with erosion in southern Taranaki Basin and deposition of the ‘Taranaki Delta’ sequence in Deepwater Taranaki. The second, West Coast–Taranaki rift phase produced north- to NE-trending extensional half-grabens in the shelfal Taranaki Basin during the latest Cretaceous–Paleocene ( c . 80 – 55 Ma). This rift was narrow (&lt;150 km wide), orthogonal to Zealandia phase rifting, affected mainly western Zealandia and did not progress to full break-up. Supplementary material: A full set of eight palaeogeographical maps as well as expanded versions of the seismic figures, with both uninterpreted and interpreted versions, are available at https://doi.org/10.6084/m9.figshare.c.3772175

Study of the effects of nuclear and Coulomb interactions in the breakup of 19C on 208Pb

A detailed partial wave analysis of the breakup of 19C on 208Pb at 67 MeV/A is performed to investigate the effects of the nuclear and Coulomb breakups. It is first shown that the breakup cross sections are dominated by p-waves, but all the outgoing neutrons are not necessarily in the p-waves. The contributions of the other partial waves are important and account for the normalization of the breakup cross section. The nuclear contribution is not negligible for angles below and in fact both nuclear and Coulomb breakups contribute equally between and . The incoherent difference of the full (coherent sum of nuclear and Coulomb breakups) and nuclear breakup cross sections agree with the data for low excitation energies. However, the full breakup cross section alone describes well the data for high excitation energies. We found that the small nuclear contribution does not directly imply small nuclear–Coulomb interferences, which was generally found to be destructive regardless whether the continuum–continuum couplings are included or not.

Breakup and reunion from a psychoanalytic perspective

This article examines from a Kleinian psychoanalytic perspective the implications of a band’s breakup and reunion on fandom. The impact and meaning of these processes for a fan’s internal world are explored using applied object relations theory. The vicissitudes of unconscious phantasies regarding internal objects and their meaning are traced from a band’s formation via the full breakup to the potential and actual reunion. Freud’s ‘Mourning and Melancholia’ serves as a basis to understand a fan’s response to the loss of an idealized object. Processes of projection and a gradual psychic integration that are characteristic of a shift from a paranoid-schizoid to a depressive position in Kleinian terms are explored in the case of Take That’s band history alongside possible psychic defences that are employed by a fan in response to a boy group’s breakup. Focusing on Kleinian theory, this article introduces the meaning of band reunions and how these relate to psychoanalytic notions of reparation and unconscious guilt.

The sedimentary, magmatic and tectonic evolution of the southwestern South China Sea revealed by seismic stratigraphic analysis

The southwestern South China Sea represents an area of continental crust frozen immediately before the onset of seafloor spreading. Here we compile a grid of multichannel seismic reflection data to characterize the continent-ocean transition just prior to full break-up. We identify a major continental block separated from the shelf margin by a basin of hyperextended crust. Oligocene-Early Miocene rifting was followed by mild compression and inversion prior to 16 Ma, probably linked to collision between the Dangerous Grounds, a continental block to the east of the study area, and Borneo. The timing of inversion supports models of seafloor spreading continuing until around 16 Ma, rather than becoming inactive at 20 Ma. The off-shelf banks experienced uplift prior to 16 Ma in an area, which had previously been a depocenter. The off-shelf banks continued to extend after this time when the rest of the region is in a phase of thermal subsidence. Post-rift magmatism is seen in the form of scattered seamounts (~5–10 km across) within or on the edge of the deeper basins, and are dated as Late Miocene and Pliocene. They are not clearly linked to any phase of tectonic activity. Further inversion of the off-shelf banks occurred in the Pliocene resulting in a major unconformity despite the lack of brittle faulting of that age. We speculate that this is part of a wider pattern of scattered magmatism throughout the South China Sea at this time. Prograding clinoforms are seen to build out from the shelf edge in the south of the study area during the Pliocene, after 5.3 Ma, and then more towards the north and east during the Pleistocene. At the same time a trough south of the off-shelf banks is filled with >1.35 km of mostly Pleistocene sediment. While we expect the bulk of the sediment to come from the Mekong River, we also suggest additional sediment supply from Borneo and the Malay Peninsula via the Molengraaff River and its predecessors.

A spin-isospin-dependent 3N scattering formalism in a 3D Faddeev scheme

We introduce a spin-isospin-dependent three-dimensional approach for the formulation of the three-nucleon scattering. The Faddeev equation is expressed in terms of vector Jacobi momenta and spin-isospin quantum numbers of each nucleon. Our formalism is based on connecting the transition amplitude T to momentum-helicity representations of the two-body t -matrix and the deuteron wave function. Finally, the expressions for nucleon-deuteron elastic scattering and full breakup process amplitudes are presented.

Excitation of two-neutron-halo nuclei in a continuum

Reactions induced by collisions of beams of unstable nuclei with nuclear targets are studied. Kinematically full breakup reactions are considered. A microscopic four-body model of the breakup of two-neutron-halo nuclei is formulated with allowance for special features of their structure. The model relies on the distorted-wave method and creates a basis for the spectroscopy of the continuous spectrum via a consistent analysis of various correlation cross sections.

One-photon two-electron processes in helium: Unity and diversity

The ab initio H R M -SOW method has established itself as the ideally fit tool to explore the three-body dynamics of the helium atom close to its full break-up threshold. Accordingly, it is used here to perform a “numerical experiment” designed to enlighten the relations between the various competing processes which may occur in the vicinity of the double ionization threshold, be it double excitation, excitation–ionization, or double ionization. More precisely, double ionization and ionization–excitation cross-sections are produced at 100 meV above the double ionization threshold. The latter, obtained up to as high a level as n = 50 , are in addition analyzed in terms of spherical and parabolic partial waves in the photo-electron frame. Based on these extensive data, we establish a continuity relation between ionization–excitation and double ionization appropriate to the near threshold region, confirm previous qualitative predictions regarding the dominant angular momentum achieved in these near threshold excitation processes, evidence the relation between ionized-excited and doubly excited states, and promote the partial parabolic ionization–excitation cross-sections as the optimal observation channels of doubly excited states.

Combined BIMA and OVRO Observations of Comet C/1999 S4 (LINEAR)

We present results from an observing campaign of the molecular content of the coma of comet C/1999 S4 (LINEAR) carried out jointly with the millimeter arrays of the Berkeley-Illinois-Maryland Association (BIMA) and the Owens Valley Radio Observatory (OVRO). Using the BIMA array in autocorrelation (single-dish) mode, we detected weak HCN J = 1–0 emission from comet C/1999 S4 (LINEAR) at 14 ± 4 mK km s^(-1) averaged over the 143 beam. The 3 days over which emission was detected, 2000 July 21.9–24.2, immediately precede the reported full breakup of the nucleus of this comet. During this same period, we find an upper limit for HCN J = 1–0 of 144 mJy beam^(-1) km s^(-1) (203 mK km s^(-1)) in the 9 × 12 synthesized beam of combined observations of BIMA and OVRO in cross-correlation (imaging) mode. Together with reported values of HCN J = 1–0 emission in the 28 IRAM 30 m beam, our data probe the spatial distribution of the HCN emission from radii of 1300 to 19,000 km. Using literature results of HCN excitation in cometary comae, we find that the relative line fluxes in the 12 × 9, 28, and 143 beams are consistent with expectations for a nuclear source of HCN and expansion of the volatile gases and evaporating icy grains following a Haser model.

Mesoscale ionospheric electrodynamics observed with the MIRACLE network: 1. Analysis of a pseudobreakup spiral

A short‐lived auroral spiral is observed on February 3, 1999, around 2204 UT, using the Multi‐Instrument Array for Ionosphere‐Magnetosphere Coupling Studies (MIRACLE) network of ground‐based instruments in Fennoscandia, which consists of magnetometers, coherent scatter radars, and all‐sky cameras. Four minutes later, after this spiral has subsided, the auroral bulge of a fully developed substorm that has set on earlier over Russia intrudes into the MIRACLE field of view from the east. Hence the auroral spiral precedes the substorm spatially (i.e., it is located westward of the substorm bulge) rather than temporarily. Since this spiral is associated with a localized and short‐lived substorm‐type auroral development, we interpret it as a “pseudobreakup spiral,” which is subsequently covered by the intruding auroral bulge, during the decaying phase of the pseudobreakup activity. In contrast to growth phase pseudobreakups that occur temporally before a full breakup, this pseudobreakup is observed spatially ahead (westward) of an already evolving substorm bulge. Our instantaneous spatial analysis of the distributions of ionospheric electrodynamic parameters associated with this spiral shows that all key features are similar to the ionospheric electrodynamics of the westward traveling surge: sharp decrease of conductance toward the west, from Hall conductance values up to 30 S in the spiral to less than 2 S west of it, a cluster of upward field‐aligned currents (FACs) in the spiral area with magnitudes up to 5 A km−2, and anticlockwise spiraling horizontal currents around it. The upward FACs, diverging at least 100 kA of current in total, are fed to a large extent by a “pseudosubstorm electrojet” carried by westward flowing Hall currents. No signs of local current closure by downward FACs from the immediate vicinity of the spiral are found. Our results are inconsistent with the earlier conjecture that insufficient ionospheric conductance would prevent the pseudobreakup to evolve to a full breakup. Since the solar wind data do not provide clear evidence for being a driver of the pseudobreakup‐breakup sequence, the driver has to be an internal magnetospheric one.

Inclusive electron scattering on 3H and 3He with full inclusion of final state interactions.

Inclusive electron scattering data on $^{3}\mathrm{He}$ and $^{3}\mathrm{H}$ are analyzed under full treatment of the final state interactions (FSI) using realistic nucleon-nucleon forces. The data are well described. We use two different methods, one where we calculate the pd and ppn breakup contributions separately and another one which is related to the optical theorem for Compton scattering. Both rely on precise solutions of Faddeev-like equations and agree perfectly. The importance of FSI and the inclusion of total isospin T=3/2 for the full breakup of $^{3}\mathrm{He}$ is demonstrated. We also comment on the Coulomb sum rule and the extraction of the proton-proton correlation function.

The unitarity relations for the four-body scattering amplitude

A formal derivation of the general unitarity relation for the four-particle transition operator is given by generalizing the three-body formalism of Karlson and Zeiger to the four-body case. From this operator relation the on-shell unitarity relations for the amplitudes that describe elastic/rearrangement, partial breakup, and full breakup scattering processes are obtained.

A multi-cluster, n-particle generalization of the three-particle faddeev wavefunction equations

Recent work applying certain forms of many-body scattering theory to problems such as molecular potential energy surfaces and equations for nonequilibrium statistical mechanics indicates that a formulation of the theory based directly on multi-cluster, n-particle, wave function components could be of some utility. Such a formulation is derived in this paper using techniques from the Baer-Kouri-Levin-Tobocman and Bencze-Redish-Sloan-Polyzou theories of multi-particle scattering. It is based on components corresponding to the various multi-cluster partitions of an n-particle scattering system and is a generalization of the three-body Faddeev wave function formalism, to which it reduces when n = 3. Except for the full breakup partition, which does not enter the equations, the new components are defined for all possible m-cluster partitions of the n-particles, 2 ≤ m ≤ n − 1. The sum of all the components yields the solution to the Schrödinger equation for scattering and either the Schrödinger equation solution or an easily identified spurious solution in the case of bound states. Both the two-cluster components and two-cluster transition operators are shown to be solutions of equations involving quantities carrying only two-cluster partition labels. Discussions of the Born term and a multiple scattering representation for the non-rearrangement transition operator and the inclusion of distortion operators in the formalism are also included.