Controlling H3+ Formation From Ethane Using Shaped Ultrafast Laser Pulses

An adaptive learning algorithm coupled with 3D momentum-based feedback is used to identify intense laser pulse shapes that control H3+ formation from ethane. Specifically, we controlled the ratio of D2H+ to D3+ produced from the D3C-CH3 isotopologue of ethane, which selects between trihydrogen cations formed from atoms on one or both sides of ethane. We are able to modify the D2H+:D3+ ratio by a factor of up to three. In addition, two-dimensional scans of linear chirp and third-order dispersion are conducted for a few fourth-order dispersion values while the D2H+ and D3+ production rates are monitored. The optimized pulse is observed to influence the yield, kinetic energy release, and angular distribution of the D2H+ ions while the D3+ ion dynamics remain relatively stable. We subsequently conducted COLTRIMS experiments on C2D6 to complement the velocity map imaging data obtained during the control experiments and measured the branching ratio of two-body double ionization. Two-body D3+ + C2D3+ is the dominant final channel containing D3+ ions, although the three-body D + D3+ + C2D2+ final state is also observed.

Supplemental Material: Quantifying structural controls on submarine channel architecture and kinematics

Figure S1: Location of cross sections through Channel Complex Five; Figure S2: Location of cross-sections taken through Channel Complex Six; Figure S3: (a) The final channel elements of channel complex five (ChC 5) and six (ChC 6) overlain on interval strain rates presented in Pizzi et al. (2020); Table S1: KS test values for channel complex five and six. Critical values based on the two sample sizes (structured (m) and unstructured (n) measurements) and Dmax values for channel complex width, thickness, aspect ratio, and complex-averaged stratigraphic mobility.

Supplemental Material: Quantifying structural controls on submarine channel architecture and kinematics

Figure S1: Location of cross sections through Channel Complex Five; Figure S2: Location of cross-sections taken through Channel Complex Six; Figure S3: (a) The final channel elements of channel complex five (ChC 5) and six (ChC 6) overlain on interval strain rates presented in Pizzi et al. (2020); Table S1: KS test values for channel complex five and six. Critical values based on the two sample sizes (structured (m) and unstructured (n) measurements) and Dmax values for channel complex width, thickness, aspect ratio, and complex-averaged stratigraphic mobility.

Subsurface heterogeneity patterns that emerge from interacting depositional processes

<p>Emergent structures define organizational patterns that spontaneously develop due to interactions between component properties or behaviors of complex dynamic systems, rather than being a simple compilation of the individual parts observed within the system at any one time. Traditional facies models used to predict subsurface lithic variations focus on defining the distribution of depositional environments on Earth’s surface and relating the hierarchy of preserved bedding units to different scales of surficial bedforms. It is increasingly recognized that such static models fail to predict the geometry and character of many types of preserved lithic bodies and discontinuity surfaces unless these observations are placed within the context of the overall evolving system. Numerical depositional process models are presented to show links between evolving depositional patterns and preserved facies patterns within different settings.</p><p>     Channel deposit internal variations tend not to be channel shaped, but rather sweet spots within the deposit resemble a string of beads, each formed as individual channel segments meander. Mouth bar deposits generally do not to have the circular to elliptical shape of a modern channel-mouth bedform, but rather tend to be more elongate fingers cut by a diachronous channel filled as river flows are choked off by loss of gradient during progradation. Although the final channel basal erosion surface appears continuous, timelines cross this surface along the length of the deposit. Deltaic shorelines that look identical at a given time preserve very different deposits when the feeding river avulses at different frequency, a condition that can change within an individual deposit formed alternately during periods of sea level rise and fall. Even major stratigraphic surfaces, like lowstand fluvial incision surfaces and wave-ravined falling stage and transgressive surfaces, are likely to gradually emerge from the migration of localized areas of erosion that were never as extensive at any one time as the preserved surface. Such surfaces may be regionally diachronous, with deposits of the same age locally preserved variably above and below the surface. Understanding emergent lithic bodies and internal heterogeneity patterns are fundamental to understanding how deposition is recorded in the rock record and for facies models used to predict how subsurface fluids move through shallow marine deposits.</p>

Ionization Cross Sections in the Collision between Two Ground State Hydrogen Atoms at Low Energies

The interaction between two ground state hydrogen atoms in a collision was studied using the four-body classical trajectory Monte Carlo method. We present the total cross sections for the dominant channels, namely for the single ionization of the target, the ionization of the projectile, resulting from pure ionization, and also from the electron transfer (capture or loss) processes. We also present cross sections for the complete break of the system, resulting in the final channel for four free particles. The calculations were carried out at low energies, relevant to the interest of fusion research. We present our cross sections in the projectile energy range between 2.0 keV and 100 keV and compare them with previously obtained theoretical and experimental results.

IMPLICATIONS OF PLUME DISCHARGE FOR TIDAL CHANNELS MORPHODYNAMICS: A COUPLED ONSHORE AND OFFSHORE SYSTEM

This contribution investigates the morphodynamic equilibrium of a funnel-shaped, well-mixed tidal channel taking into account the existing dynamical coupling between the tidal channel itself and the related offshore sediment-laden plume. We use a quasi two-dimensional numerical model that resolves the fully nonlinear unsteady shallow water, sediment bed load transport and suspended sediment advection-diffusion equations along with the Exner equation for the bathymetric changes. We close this model by including a dynamic boundary condition at the channel mouth that transfers the offshore plume sediment concentration to the channel dynamics. This model reveals that the offshore plume reduces the timescales to reach equilibrium of the channel and plays a crucial role on shaping it. At equilibrium, the non-plume influence case attains a quasi-linear profile of constant slope in the seaward part. However, the bottom profile in the case that includes the offshore plume tends to increase the concavity of the bottom profile, reducing the final channel mouth depth. Finally, numerical results suggest that the plume characteristics are altered as a consequence of tidal channel evolution.

What Accounts for the Union Member Advantage in Voter Turnout? Evidence from the European Union, 2002-2008

Across countries, union membership and voter turnout are highly correlated. In unadjusted terms, union members maintain a roughly 0.10 to 0.12 point gap in voting propensity over non-members. We motivate empirically and propose a model—with three causal channels—that explains this correlation and then empirically tests for the contribution of each channel to the overall union voting gap. The first channel by which union members are more likely to vote is through the so-called "monopoly-face" of unionism (i.e., unionization increases wages for members and higher incomes are a significant positive determinant of voting). The second is the so-called "social custom" model of unionism, which argues that union co-worker peer pressure creates incentives to vote amongst members for the purpose of having cast a ballot or being seen at the voting poll. The third and final channel is based on the "voice-face" of unionism whereby employees who are (or have been) exposed to the formalities of collective bargaining and union representation at the workplace are also more likely to increase their attachment to structures of democratic governance in society as well. We test to see how much of the raw "union voting premium" is accounted for by these three competing channels, using contemporary data from 29 European countries. We find that all three channels are at work, with voice the dominant effect (half of the overall gap attributed to this channel) and the other two (monopoly and social custom), each accounting for approximately one-fourth of the overall union voting gap.

THEORETICAL STUDY OF THE 11Li β DECAY INTO THE DEUTERON CHANNEL IN A CLUSTER MODEL

The β-decay process of the 11 Li halo nucleus into 9 Li and d is reanalyzed within a three-body model. The 11 Li nucleus is described as a 9 Li +n+n system in hyperspherical coordinates. The transition probability per time and energy units measured in a recent experiment can be reproduced with a broad resonance located around 0.8 MeV and a weak absorption from the 9 Li + d final channel.