Environmental Response in Coupled Energy and Water Cloud Impact Parameters Derived from A-Train Satellite, ERA-Interim and MERRA-2

Understanding the connections between latent heating from precipitation and cloud radiative effects is essential for accurately parameterizing cross-scale links between cloud microphysics and global energy and water cycles in climate models. While commonly examined separately, this study adopts two cloud impact parameters (CIPs), the surface radiative cooling efficiency, Rc, and atmospheric radiative heating efficiency, Rh, that explicitly couple cloud radiative effects and precipitation to characterize how efficiently precipitating cloud systems influence the energy budget and water cycle using A-Train observations and two reanalyses. These CIPs exhibit distinct global distributions that suggest cloud energy and water cycle coupling are highly dependent on cloud regime. The dynamic regime (ω500) controls the sign of Rh, while column water vapor (CWV) appears to be the larger control on the magnitude. The magnitude of Rc is highly coupled to the dynamic regime. Observations show that clouds cool the surface very efficiently per unit rainfall at both low and high sea surface temperature (SST) and CWV, but reanalyses only capture the former. Reanalyses fail to simulate strong Rh and moderate Rc in deep convection environments but produce stronger Rc and Rh than observations in shallow, warm rain systems in marine stratocumulus regions. While reanalyses generate fairly similar climatologies in the frequency of environmental states, the response of Rc and Rh to SST and CWV results in systematic differences in zonal and meridional gradients of cloud atmospheric heating and surface cooling relative to A-Train observations that may have significant implications for global circulations and cloud feedbacks.

Parameter identification of a second-gradient model for the description of pantographic structures in dynamic regime

Pantographic structures are examples of metamaterials with such a microstructure that higher-gradient terms’ role is increased in the mechanical response. In this work, we aim for validating parameters of a reduced-order model for a pantographic structure. Experimental tests are carried out by applying forced oscillation to 3D-printed specimens for a range of frequencies. A second-gradient coarse-grained nonlinear model is utilized for obtaining a homogenized 2D description of the pantographic structure. By inverse analysis and through an automatized optimization algorithm, the parameters of the model are identified for the corresponding pantographic structure. By comparing the displacement plots, the performance of the model and the identified parameters are assessed for dynamic regime. Qualitative and quantitative analyses for different frequency ranges are performed. A good agreement is present far away from the eigenfrequencies. The discrepancies near the eigenfrequencies are a possible indication of the significance of higher-order inertia in the model.

Evolutionary dynamics of a virus in a vaccinated population

The progress of an epidemic in a small closed community is simulated by an agent-based model which allows vaccination and variation. The attributes of the virus are governed by two genetic loci: the P-locus, which determines growth, and the M-locus, which determines immune characteristics. Mutation at either locus modifies the attributes of the virus and leads to evolution through natural selection. For both loci the crucial variable is the potential mutation supply UPot, because evolution is likely to happen when UPot > 1. Mutation at the P-locus causes a limited increase in virulence, which may be affected by vaccine design. Mutation at the M-locus may cause a qualitative shift of dynamic regime from a simple limited epidemic to a perennial endemic disease by giving rise to escape mutants which may themselves mutate. A broad vaccine that remains efficacious despite several mutations at the M-locus prevents this shift and provides protection despite the evolution of the virus. Escape variants may nevertheless arise through recombination after coinfection, and can be suppressed by timely revaccination, using the prevalent strain to design the vaccine.

Resource Management Under Catastrophic Threats

We survey the rapidly growing economic literature on environmental catastrophes and the various approaches developed to address the hovering threats. Various theoretical descriptions of catastrophic occurrences are classified with respect to the uncertain conditions that trigger the events, the postoccurrence dynamic regime, and the form of the inflicted damage. We show that variations in each of these characteristics strongly affect the ensuing optimal response to the threats. The basic setup is then extended in several dimensions, allowing the modeler to consider more realistic formulations of catastrophic scenarios. Recent efforts to incorporate catastrophic events within large-scale numerical schemes to study the global climate change problem are reviewed. The number of publications in this vein increases in tandem with the growing number of disasters reported globally and their scale of damage, reflecting the growing concern that this phenomenon portends environmental collapse. Expected final online publication date for the Annual Review of Resource Economics, Volume 13 is October 2021. Please see http://www.annualreviews.org/page/journal/pubdates for revised estimates.

A Facile Synthesis Route of Hybrid Polyurea-Polyurethane-MWCNTs Nanocomposite Coatings for Ballistic Protection and Experimental Testing in Dynamic Regime

This study describes a simple, practical, inexpensive, improved, and efficient novel method for obtaining polyurea-polyurethane-multiwall carbon nanotubes (MWCNTs) nanocomposites with enhanced mechanical properties, and their experimental testing in a dynamic regime. SEM and micro-CT investigations validated the homogeneity of the nanocomposite films and uniform dispersion of the nanofiller inside the polymeric matrix. The experimental measurements (TGA, DSC, DMA, and tensile tests) revealed improved thermal and mechanical properties of these new materials. To demonstrate that these nanocomposites are suitable for ballistic protection, impact tests were performed on aluminum plates coated with the polyurea-polyurethane MWCNTs nanocomposites, using a Hopkinson bar set-up. The experimental testing in the dynamic regime of the polyurea- polyurethane-coated aluminum plates confirmed that the nanocomposite layers allow the metal plate to maintain its integrity at a maximum force value that is almost 200% higher than for the uncoated metallic specimens.

Instrumental Uncertainty of Conductance Transducers for Maritime Reduced-Scale Models

This paper aims to determine the instrumental measurement uncertainty of conductance transducers for maritime reduced-scale models developed in hydraulic experimental facilities. These transducers are used for the measurements of wave levels and their variations under a dynamic regime (being the measurement principle and method briefly described in the paper). Several metrological characterization methods are also presented, aiming to identify and quantify measurement uncertainty components, namely electrical stability, linearity, reversibility, repeatability, and thermal influence. The obtained results were applied in the evaluation of the transducer instrumental measurement uncertainty.