Mapping Of Dynamics Research Articles

Nanoscale spatial mapping of charge carrier dynamics in perovskite solar cells

Abstract Charge carrier dynamics and behaviors are key parameters and need to be mapped at the nanoscale in order to search for correct materials for high-performance solar cells. Unfortunately, currently, there are no existing tools or capabilities that can simultaneously map charge carrier dynamics at nanometer range in solar cells. Here we use a Transient Photo-response AFM (TP-AFM) to map for the first time apparent carrier recombination lifetime (τr), transport time (τt) and diffusion length (LD) in hybrid perovskites solar cells. These spatially resolved parameters reveal substantial variations at grain boundaries (GBs) of perovskites. Improved τr, τt and LD at GBs broaden the performance of these state-of-the-art mixed cation perovskites. Detail analysis of these parameters allow us to conclude that reduced density of trap states and recombination in mixed cation perovskites at GBs and its surrounding locations (extending to several nanometers into the grain interior) implies less ion migration. This first of its kind experimental realization of nanoscale mapping of charge carrier dynamics in photovoltaic materials can be used for applications in other optoelectronic devices.

Cartographic Methods of the Research of the Rural Settlement System in Volgograd Region

The article presents the methodology of cartographic support of economic and geographical research of rural territories in Volgograd region. The methodological basis of the article is the theoretical foundations of classical economic geography and applied directions of geoinformation mapping. The authors consider the stages of the study, including: identification of mapped indicators; formation of an information base; compilation of thematic maps for each indicator; compilation of an integrated assessment card for a set of indicators. The following are proposed as the main mapped indicators: the number of rural population in 2010, % by 1969; density of the rural population in 2010, people / km2; grouping of rural settlements by population, people; grouping of rural settlements by extrapolation tendency; conditions of the temporary transport accessibility of Volgograd; conditions of the temporary transport accessibility of the district center; natural fertility of agricultural lands in bonitet points. When constructing thematic maps, methods for classifying numerical fields are used, based on the calculation of the standard deviation: for maps of population dynamics, population density, and soil quality of agricultural land. Isoline mapping is used in the construction of maps of temporary transport accessibility, where the main methods of mapping are isochrones. To conduct a comprehensive assessment of the favorable resource potential of rural areas, the method of applying thematic maps is used, i.e. overlay operations. The methodology proposed by the authors as a whole allows the formation of an information database that includes information on the dynamics of the rural population in Volgograd region for individual villages, individual rural settlements, the density of the rural population in rural settlements, the conditions of transport accessibility of rural settlements, and the natural fertility of agricultural land in rural settlements, on the differences in resource potential in rural settlements.

Researching the economic dynamics of high technology products

Subject. The article addresses the issue of adequate representation of economic dynamics. It considers the need to take into account internal nonlinear processes being an important factor and additional mechanism for managing the economic dynamics. Objectives. The purpose is to rationalize a transition to a new probabilistic mapping of economic dynamics based on modern methods of nonlinear dynamics, which enables to establish the relationship between internal nonlinear processes and macroeconomic indicators of the economic system. Methods. We employ a systems analysis of stages of State-run programs formation, a probabilistic approach to representing the economic dynamics on the basis of fundamental concepts and methods of nonlinear dynamics. Results. We analyzed the cycles of government program formation for developing the high-tech products, established the identity of the main stages of economic and nonlinear dynamics. We also designed a methodology for studying the economic dynamics, which rests on the use of nonlinear dynamics methods. Modeling the processes of economic dynamics made it possible to determine the causes of its sensitivity to initial conditions and exponential divergence of its trajectory at initial stages of government programs formation. The paper presents methods to choose the optimal model of economic dynamics when substantiating and drafting the said programs. Conclusions. The findings can be used to improve methodological tools for managing the creation of high-tech products when elaborating long-term technological programs, to reduce risk inherent in their implementation, to determine methods and ways for sustainable innovative and technological development of the country.

Hi-D: nanoscale mapping of nuclear dynamics in single living cells

Bulk chromatin motion has not been analyzed at high resolution. We present Hi-D, a method to quantitatively map dynamics of chromatin and abundant nuclear proteins for every pixel simultaneously over the entire nucleus from fluorescence image series. Hi-D combines reconstruction of chromatin motion and classification of local diffusion processes by Bayesian inference. We show that DNA dynamics in the nuclear interior are spatially partitioned into 0.3–3-μm domains in a mosaic-like pattern, uncoupled from chromatin compaction. This pattern was remodeled in response to transcriptional activity. Hi-D can be applied to any dense and bulk structures opening new perspectives towards understanding motion of nuclear molecules.

Predicting biomass dynamics at the national extent from digital aerial photogrammetry

The demand for precise mapping and monitoring of forest resources, such as above ground biomass (AGB), has increased rapidly. National accounting and monitoring of AGB requires regularly updated information based on consistent methods. While remote sensing technologies such as airborne laser scanning (ALS) and digital aerial photogrammetry (DAP) have been shown to deliver the necessary 3D spatial data for AGB mapping, the capacity of repeat acquisition, remotely sensed, vegetation structure data for AGB monitoring has received less attention. Here, we use vegetation height models (VHMs) derived from repeat acquisition DAP data (with ALS terrain correction) to map and monitor woody AGB dynamics across Switzerland over 35 years (1983-2017 inclusive), using a linear least-squares regression approach. We demonstrate a consistent relationship between canopy height derived from DAP and field-based NFI measures of woody AGB across four inventory periods. Over the environmentally heterogeneous area of Switzerland, our models have a comparable predictive performance (R2 = 0.54) to previous work predicting AGB based on ALS metrics. Pearson correlation coefficients between measured and predicted changes in woody AGB over time increased with shorter time gaps (< 2 years) between image capture and field-based measurements, ranging between 0.76 and 0.34. A close temporal match between field surveys and remote sensing data acquisition is thus key to reliable mapping and monitoring of AGB dynamics, especially in areas where forest management and natural disturbances trigger relatively fast canopy dynamics. We show that VHMs derived from repeat DAP capture constitute a cost effective and reliable approach to map and monitor changes in woody AGB at a national extent and can provide an important information source for national carbon accounting and monitoring of ecosystem service provisioning.

Coexistent multiple-stability of a fractional-order delayed memristive Chua’s system based on describing function

In this paper, in order to analyze the coexistent multiple-stability of system, a fractional-order memristive Chua’s circuit with time delay is proposed, which is composed of a passive flux-controlled memristor and a negative conductance as a parallel combination. First, the Chua’s circuit can be considered as a nonlinear feedback system consisting of a nonlinear block and a linear block with low-pass properties. In the complex plane, the nonlinear element of the system can be approximated by a variable gain called a describing function. Second, compared with conventional computation, the describing function can accurately predict the hidden dynamics, fixed points, periodic orbits, unstable behaviors of the system. By using this method, the full mapping of the system dynamics in parameter spaces is presented, and the coexistent multiple-stability of the system is investigated in detail. Third, using bifurcation diagram, phase diagram, time domain diagram and power spectrum diagram, the dynamical behaviors of the system under different system parameters and initial values are discussed. Finally, based on Adams–Bashforth–Moulton (ABM) method, the correctness of theoretical analysis is verified by numerical simulation, which shows that the fractional-order delayed memristive Chua’s system has complex coexistent multiple-stability.

Spatiotemporal tracking of carbon emissions and uptake using time series analysis of Landsat data: A spatially explicit carbon bookkeeping model

Reducing terrestrial carbon emissions to the atmosphere requires accurate measuring, reporting and verification of land surface activities that emit or sequester carbon. Many carbon accounting practices in use today provide only regionally aggregated estimates and neglect the spatial variation of pre-disturbance forest conditions and post-disturbance land cover dynamics. Here, we present a spatially explicit carbon bookkeeping model that utilizes a high-resolution map of aboveground biomass and land cover dynamics derived from time series analysis of Landsat data. The model produces estimates of carbon emissions/uptake with model uncertainty at Landsat resolution. In a case study of the Colombian Amazon, an area of 47 million ha, the model estimated total emissions of 3.97 ± 0.71 Tg C yr−1 and uptake by regenerating forests of 1.11 ± 0.23 Tg C yr−1 2001–2015, with an additional 45.1 ± 7.99 Tg of carbon remaining in the form of woody products, decomposing slash and charcoal at the end of 2015 (estimates provided with ±95% confidence intervals). Total emissions attributed to the study period (including carbon not yet released) is 6.97 ± 1.24 Tg C yr−1. The presented model is based on recent technological advancements in the field of remote sensing to achieve spatially explicit modeling of carbon emissions and uptake associated with land surface changes and post-disturbance landscapes that is compliant with international reporting criteria.

Изменение температуры воздуха в Крыму

The article presents the results of spatial and temporal dynamics research of the air temperature fields on the territory of the Crimean Peninsula due to the change of circulation epochs and periods of the Northern Hemisphere. Average multiannual maps of air temperature on the Crimean Peninsula for each circulating epoch and period were obtained, as well as maps of temperature fields dynamics at their change. Based on the obtained analysis of the maps it was found out that change in air temperature occurred not synchronously, but had its own characteristics in different regions of the Crimean Peninsula, which is explained by the influence of local factors. Zones characterized by constant maximum air temperatures in all considered periods have been recorded. It was found that during the instrumental observations on the Crimean Peninsula the warming occurred by 1 °C. This warming was occurring during the last circulation period.

Predictive mapping of the spatio-temporal dynamics of ecosystems with multidirectional trends in climatic humidification in subarid conditions

Predictive mapping of the spatio-temporal dynamics of ecosystems with multidirectional trends in climatic humidification in subarid conditions

Maps of flame dynamics for premixed lean hydrogen-air combustion in a heated microchannel

In the present work, flame dynamics are extracted for combustion of premixed lean hydrogen-air in a heated microchannel using numerical simulation. In this simulation, Navier-Stokes equations along with energy and species conservation equations are considered by formulation of low Mach number and with consideration of detail chemical kinetics. Regarding different conditions, three dynamics are observed in the microchannel which are periodic repetitive ignition-extinction, steady symmetric flame, and steady asymmetric flame. The effects of different parameters such as inlet velocity, equivalence ratio, and channel width are investigated on the flame dynamics. The periodic repetitive ignition-extinction dynamics is observed at low velocities close to the lower flammability limit. Upon increasing the inlet velocity and creating a balance between the reaction time and fluid residence time in the channel, a steady symmetric flame is shown in the channel. In this situation, the maximum temperature and mass fraction of species are located on the symmetry line of the channel. Then by increasing the inlet velocity in a specific channel, the flame moves toward downstream at the symmetry line of the channel and it will be stretch near the walls. Hence, the surface of the flame front is susceptible to instability and becomes unstable due to the flow perturbations. The maps of flame dynamics in the small scales are presented for the hydrogen-air mixture based on three parameters, inlet velocity, and equivalence ratio and channel width in the microchannel. The obtained results show that by increasing the equivalence ratio, channel width, and inlet velocity, the steady symmetric dynamics is eliminated, replaced by a steady asymmetric dynamics.

The importance of physiological, structural and trait responses to drought stress in driving spatial and temporal variation in GPP across Amazon forests

Abstract. The capacity of Amazon forests to sequester carbon is threatened by climate-change-induced shifts in precipitation patterns. However, the relative importance of plant physiology, ecosystem structure and trait composition responses in determining variation in gross primary productivity (GPP) remain largely unquantified and vary among models. We evaluate the relative importance of key climate constraints to GPP, comparing direct plant physiological responses to water availability and indirect structural and trait responses (via changes to leaf area index (LAI), roots and photosynthetic capacity). To separate these factors we combined the soil–plant–atmosphere model with forcing and observational data from seven intensively studied forest plots along an Amazon drought stress gradient. We also used machine learning to evaluate the relative importance of individual climate factors across sites. Our model experiments showed that variation in LAI was the principal driver of differences in GPP across the gradient, accounting for 33 % of observed variation. Differences in photosynthetic capacity (Vcmax and Jmax) accounted for 21 % of variance, and climate (which included physiological responses) accounted for 16 %. Sensitivity to differences in climate was highest where a shallow rooting depth was coupled with a high LAI. On sub-annual timescales, the relative importance of LAI in driving GPP increased with drought stress (R2=0.72), coincident with the decreased importance of solar radiation (R2=0.90). Given the role of LAI in driving GPP across Amazon forests, improved mapping of canopy dynamics is critical, opportunities for which are offered by new satellite-based remote sensing missions such as GEDI, Sentinel and FLEX.

Plasmonic Lenses for Tunable Ultrafast Electron Emitters at the Nanoscale

Simultaneous spatio-temporal confinement of energetic electron pulses to femtosecond and nanometer scales is a topic of great interest in the scientific community, given the potential impact of such development on a wide spectrum of scientific and industrial applications. For example, in ultrafast electron scattering, nanoscale probes would enable accurate maps of structural dynamics in materials with nanoscale heterogeneity, thereby understanding the role of boundaries and defects on macroscopic properties. On the other hand, advances in this field are mostly limited by the electron source brightness and size. We present the design, fabrication, and optical characterization of bullseye plasmonic lenses for next-generation ultrafast electron sources. Using electromagnetic simulations, we examine how the interplay between light-plasmon coupling, plasmon propagation, dispersion, and resonance governs the properties of the photoemitted electron pulse. We also illustrate how the pulse duration and strength can be tuned by geometric design, and predict sub-10 fs pulses with nanoscale diameter can be achieved. We then fabricated lenses in gold films and characterized their plasmonic properties with cathodoluminescence spectromicroscopy, demonstrating suitable plasmonic behavior for ultrafast, nanoscale photoemission.

Network Analysis of Substituted Bullvalenes.

Substituted bullvalenes are dynamic shape-shifting molecules that exist within complex reaction networks. Herein, we report the synthesis of di- and trisubstituted bullvalenes and investigate their dynamic properties. Trisubstituted bullvalenes share a common major isomer which shows kinetic metastability. A survey of the thermodynamic and kinetic landscapes through computational analysis together with kinetic simulation provides a map of the internal dynamics of these systems.

Performance-based spatial monitoring. An interpretative model for long-term shrinking medium-small Italian towns

The paper illustrates a GIS-based methodology to identify, among medium-small Italian towns, shrinking clusters characterised by homogeneous shrinking patterns in a 25-year-time frame. This methodology main goal is to act as a preliminary cognitive tool to which urban policies may refer to, providing support in the related decision-making process and encouraging an efficient management of social, economic and environmental resources in small deprived contexts.The definition of the methodology foresees the following three main steps: 1) The mapping of demographic decline dynamics in a 25-year-time frame. 2) The identification of performance-based indicators which are involved in population loss in medium-small Italian towns. 3) The setting up of a performance-based interpretative scheme for classifying medium-small Italian towns in clusters having similar decline patterns. This contribution finally suggests a possible further application of the illustrated methodology as an urban planning efficiency monitoring tool, highlighting the main unsustainable trends connected to urban sprawl and to the continuous decrease in urban densities.

In-situ full-field mapping of melt flow dynamics in laser metal additive manufacturing

Melt flow plays a critical role in laser metal additive manufacturing, yet the melt flow behavior within the melt pool has never been explicitly presented. Here, we report in-situ characterization of melt-flow dynamics in every location of the entire melt pool in laser metal additive manufacturing by populous and uniformly dispersed micro-tracers through in-situ high-resolution synchrotron x-ray imaging. The location-specific flow patterns in different regions of the melt pool are revealed and quantified under both conduction-mode and depression-mode melting. The physical processes at different locations in the melt pool are identified. The full-field melt-flow mapping approach reported here opens the way to study the detailed melt-flow dynamics under real additive manufacturing conditions. The results obtained provide crucial insights into laser additive manufacturing processes and are critical for developing reliable high-fidelity computational models.

Local electromagnetic properties and hysteresis losses in uniformly and non-uniformly wound superconducting racetrack coils

A noteworthy physical dependence of the hysteresis losses with the axial winding misalignment of superconducting racetrack coils made with commercial second generation high temperature superconducting (2G-HTS) tapes is reported. A comprehensive study on the influence of the turn-to-turn misalignment factor on the local electromagnetic properties of individual turns is presented by considering six different coil arrangements and ten amplitudes for the applied alternating transport current, Ia, together with an experimentally determined function for the magneto-angular anisotropy properties of the critical current density, Jc(B,θ), across the superconducting tape. It has been found that for moderate to low applied currents Ia≤0.6Ic0, with Ic0 the self-field critical current of individual tapes, the resulting hysteretic losses under extreme winding deformations can lead to an increase in the energy losses of up to 25% the losses generated by a perfectly wound coil. High-level meshing considerations have been applied in order to get a realistic account of the local and global electromagnetic properties of racetrack coils, including a mapping of the flux front dynamics with well defined zones for the occurrence of magnetization currents, transport currents, and flux-free cores, which simultaneously has enabled an adequate resolution for determining the experimental conditions when turn-to-turn misalignments of the order of 20–100 μm in a 20 turns 4mm wide racetrack coil can lead not only to the increment of the AC losses but also to its reduction. In this sense, we have shown that for transport current amplitudes Ia&amp;gt;0.7Ic0, a slight reduction in the hysteresis losses can be achieved as a consequence of the winding displacement, which is at the same time connected with the size reduction of the flux-free core at the coil central turns. Our findings can be used as a practical benchmark to determine the relative losses for any 2G-HTS racetrack coil application, unveiling the physical fingerprints that possible coil winding misalignments could infer.

Minimal dynamical systems model of the Northern Hemisphere jet stream via embedding of climate data

Abstract. We derive a minimal dynamical systems model for the Northern Hemisphere midlatitude jet dynamics by embedding atmospheric data and by investigating its properties (bifurcation structure, stability, local dimensions) for different atmospheric flow regimes. The derivation is a three-step process: first, we obtain a 1-D description of the midlatitude jet stream by computing the position of the jet at each longitude using ERA-Interim. Next, we use the embedding procedure to derive a map of the local jet position dynamics. Finally, we introduce the coupling and stochastic effects deriving from both atmospheric turbulence and topographic disturbances to the jet. We then analyze the dynamical properties of the model in different regimes: one that gives the closest representation of the properties extracted from real data; one featuring a stronger jet (strong coupling); one featuring a weaker jet (weak coupling); and one with modified topography. Our model, notwithstanding its simplicity, provides an instructive description of the dynamical properties of the atmospheric jet.

ASSESSMENT OF LANDSLIDE-INDUCED MORPHOLOGY CHANGES USING AN OBJECT-BASED IMAGE ANALYSIS APPROACH: A CASE STUDY OF HÍTARDALUR, ICELAND

Abstract. On July 7, 2018, a large landslide occurred at the eastern slope of the Fagraskógarfjall Mountain in Hítardalur valley in West Iceland. The landslide dammed the river, led to the formation of a lake and, consequently, to a change in the river course. The main focus of this research is to develop a knowledge-based expert system using an object-based image analysis (OBIA) approach for identifying morphology changes caused by the Hítardalur landslide. We use synthetic aperture radar (SAR) and optical remote sensing data, in particular from Sentinel-1/2 for detection of the landslide and its effects on the river system. We extracted and classified the landslide area, the landslide-dammed lake, other lakes and the river course using intensity information from S1 and spectral information from S2 in the object-based framework. Future research will focus on further developing this approach to support mapping and monitoring of the spatio-temporal dynamics of surface morphology in an object-based framework by combining SAR and optical data. The results can reveal details on the applicability of different remote sensing data for the spatio-temporal investigation of landslides, landslide-induced river course changes and lake formation and lead to a better understanding of the impact of large landslides on river systems.

Probing the Spatial Heterogeneity of Carrier Relaxation Dynamics in CH3NH3PbI3 Perovskite Thin Films with Femtosecond Time‐Resolved Nonlinear Optical Microscopy

AbstractThe spatial heterogeneity of carrier dynamics in polycrystalline metal halide perovskite (MHP) thin films has a strong influence on photovoltaic device performance; however, the underlying cause is not yet clearly understood. Here, the sub‐micrometer scale mapping of charge carrier dynamics in CH3NH3PbI3 thin films using time‐resolved nonlinear optical microscopy, specifically transient absorption microscopy (TAM) with sub‐picosecond (ps) and time‐resolved photoluminescence (PL) microscopy with nanosecond temporal resolution is reported. To study the influence of physical morphology on charge carrier dynamics, MHP thin films having granular‐ and fibrous structures are investigated. On both types of films, spatial regions with short‐lived transient gain signals (fast nonradiative relaxation within ≈1 ps) typically show slower charge recombination via radiative relaxation, which is attributed to the presence of additional energy states near the band edge. In addition, fibrous films show longer PL lifetimes. Interestingly, the functional contrast shown in TAM images exhibits fundamental differences from the structural contrast shown in scanning electron microscopy images, implying that the variation of trap density in the bulk contributes to the observed spatial heterogeneity in carrier dynamics.

Semiquantitative Proteomics Enables Mapping of Murine Neutrophil Dynamics following Lethal Influenza Virus Infection.

Neutrophils are rapidly deployed innate immune cells, and excessive recruitment is causally associated with influenza-induced pathologic conditions. Despite this, the complete set of influenza lethality-associated neutrophil effector proteins is currently unknown. Whether the expression of these proteins is predetermined during bone marrow (BM) neutrophil maturation or further modulated by tissue compartment transitions has also not been comprehensively characterized at a proteome-wide scale. In this study, we used high-resolution mass spectrometry to map how the proteomes of murine neutrophils change comparatively across BM, blood, and the alveolar airspaces to deploy an influenza lethality-associated response. Following lethal influenza infection, mature neutrophils undergo two infection-dependent and one context-independent compartmental transitions. Translation of type I IFN-stimulated genes is first elevated in the BM, preceding the context-independent downregulation of ribosomal proteins observed in blood neutrophils. Following alveolar airspace infiltration, the bronchoalveolar lavage (BAL) neutrophil proteome is further characterized by a limited increase in type I IFN-stimulated and metal-sequestering proteins as well as a decrease in degranulation-associated proteins. An influenza-selective and dose-dependent increase in antiviral and lipid metabolism-associated proteins was also observed in BAL neutrophils, indicative of a modest capacity for pathogen response tuning. Altogether, our study provides new and comprehensive evidence that the BAL neutrophil proteome is shaped by BM neutrophil maturation as well as subsequent compartmental transitions following lethal influenza infection.