General purpose airborne simulator - Conceptual design report

General purpose airborne simulator with capabilities for model controlled and response feedback types of variable stability operatio

A Correlation Between Changes in Solar Luminosity and Differential Radius Measurements

Solar luminosity variations occurring during solar cycle 21 can be attributed in large part to the presence of sunspots and faculae. Nevertheless, there remains a residual portion of the luminosity variation distinctly unaccounted for by these phenomena of solar activity. At the Santa Catalina Laboratory for Experimental Relativity by Astrometry (SCLERA), observations of the solar limb are capable of detecting changes in the solar limb darkening function by monitoring a quantity known as the differential radius. These observations are utilized in such a way that the effects of solar activity are minimized in order to reveal the more fundamental structure of the photosphere. The results of observations made during solar cycle 21 at various solar latitudes indicate that a measurable change did occur in the global photospheric limb darkening function. It is proposed that the residual luminosity change is associated in part with this change in limb darkening

Development of a general purpose airborne simulator

Variable stability system development for General Purpose Airborne Simulator /GPAS

Kinetic modeling of Secondary Organic Aerosol formation: effects of particle- and gas-phase reactions of semivolatile products

The distinguishing mechanism of formation of secondary organic aerosol (SOA) is the partitioning of semivolatile hydrocarbon oxidation products between the gas and aerosol phases. While SOA formation is typically described in terms of partitioning only, the rate of formation and ultimate yield of SOA can also depend on the kinetics of both gas- and aerosol-phase processes. We present a general equilibrium/kinetic model of SOA formation that provides a framework for evaluating the extent to which the controlling mechanisms of SOA formation can be inferred from laboratory chamber data. With this model we examine the effect on SOA formation of gas-phase oxidation of first-generation products to either more or less volatile species, of particle-phase reaction (both first- and second-order kinetics), of the rate of parent hydrocarbon oxidation, and of the extent of reaction of the parent hydrocarbon. The effect of pre-existing organic aerosol mass on SOA yield, an issue of direct relevance to the translation of laboratory data to atmospheric applications, is examined. The importance of direct chemical measurements of gas- and particle-phase species is underscored in identifying SOA formation mechanisms

Polarization dependence of x-ray absorption spectra in Na_xCoO_2

In order to shed light on the electronic structure of Na_xCoO_2, and motivated by recent Co L-edge X-ray absorption spectra (XAS) experiments with polarized light, we calculate the electronic spectrum of a CoO_6 cluster including all interactions between 3d orbitals. We obtain the ground state for two electronic occupations in the cluster that correspond nominally to all O in the O^{-2} oxidation state, and Co^{+3} or Co^{+4}. Then, all excited states obtained by promotion of a Co 2p electron to a 3d electron, and the corresponding matrix elements are calculated. A fit of the observed experimental spectra is good and points out a large Co-O covalency and cubic crystal field effects, that result in low spin Co 3d configurations. Our results indicate that the effective hopping between different Co atoms plays a major role in determining the symmetry of the ground state in the lattice. Remaining quantitative discrepancies with the XAS experiments are expected to come from composition effects of itineracy in the ground and excited states.Comment: 10 pages, 4 figure

Transformations to achieve the Sustainable Development Goals Includes the SDG Index and Dashboards. Sustainable Development Report 2019

The Sustainable Development Report 2019 presents an updated SDG Index and Dashboards with a refined assessment of countries’ distance to SDG targets. The report has been successfully audited for the first time by the European Commission Joint Research Centre. New indicators have been included, primarily to refine the indicator selection on agriculture, diets, gender equality and freedom of speech. We have also added more metrics for international spillovers, including on fatal work accidents. A new website and data visualization tools are available (http://sustainabledevelopment.report). Once again, Nordic countries – Denmark, Sweden and Finland – top the SDG Index. Yet, even these countries face major challenges in implementing one or several SDGs. No country is on track for achieving all 17 goals with major performance gaps even in the top countries on SDG 12 (Responsible Consumption and Production), SDG 13 (Climate Action), SDG 14 (Life Below Water) and SDG 15 (Life on Land). Income and wealth inequalities, as well as gaps in health and education outcomes by population groups also remain important policy challenges in developing and developed countries alike. The Sustainable Development Report 2019 generates seven major findings: 1. High-level political commitment to the SDGs is falling short of historic promises In September 2019, heads-of-states and governments will convene for the first time in person at the UN in New York to review progress on their promises made four years after the adoption of the 2030 Agenda. Yet, our in-depth analyses show that many have not taken the critical steps to implement the SDGs. Out of 43 countries surveyed on SDG implementation efforts, including all G20 countries and countries with a population greater than 100 million, 33 countries have endorsed the SDGs in official statements since January 1st, 2018. Yet in only 18 of them do central budget documents mention the SDGs. This gap between rhetoric and action must be closed. 2. The SDGs can be operationalized through six SDG Transformations SDG implementation can be organized along the following Transformations: 1. Education, Gender, and Inequality; 2. Health, Wellbeing, and Demography; 3. Energy Decarbonization and Sustainable Industry; 4. Sustainable Food, Land, Water, Oceans; 5. Sustainable Cities and Communities; and 6. Digital Revolution for Sustainable Development. The transformations respect strong interdependencies across the SDGs and can be operationalized by well-defined parts of governments in collaboration with civil society, business, and other stakeholders. They must be underpinned and guided by the principles of Leave No One Behind and Circularity and Decoupling of resource use from human wellbeing. 3. Trends on climate (SDG 13) and biodiversity (SDG 14 and SDG 15) are alarming On average, countries obtain their worst scores on SDG 13 (Climate Action), SDG 14 (Life Below Water) and SDG 15 (Life on Land). No country obtains a “green rating” (synonym of SDG achieved) on SDG 14 (Life Below Water). Trends on greenhouse gas emissions and, even more so, on threatened species are moving in the wrong direction. These findings are in line with the recent reports from the IPCC and IPBES on climate change mitigation and biodiversity protection, respectively. 4. Sustainable land-use and healthy diets require integrated agriculture, climate and health policy interventions Land use and food production are not meeting people’s needs. Agriculture destroys forests and biodiversity, squanders water and releases one-quarter of global greenhouse-gas emissions. In total, 78% of world nations for which data are available obtain a “red rating” (synonym of major SDG challenge) on sustainable nitrogen management; the highest number of “red” rating across all indicators included in the report. At the same time, one-third of food is wasted, 800 million people remain undernourished, 2 billion are deficient in micronutrients, and obesity is on the rise. New indicators on nations’ trophic level and yield gap closure highlight the depth of the challenge. Transformations towards sustainable landuse and food systems are required to balance efficient and resilient agriculture and forestry with biodiversity conservation and restoration as well as healthy diets

Effective Hamiltonian for transition-metal compounds. Application to Na_xCoO_2

We describe a simple scheme to construct a low-energy effective Hamiltonian H_eff for highly correlated systems containing non-metals like O, P or As (O in what follows) and a transition-metal (M) as the active part in the electronic structure, eliminating the O degrees of freedom from a starting Hamiltonian that contains all M d orbitals and all non-metal p orbitals. We calculate all interaction terms between d electrons originating from Coulomb repulsion, as a function of three parameters (F_0, F_2 and F_4) and write them in a basis of orbitals appropriate for cubic, tetragonal, tetrahedral or hexagonal symmetry around M. The approach is based on solving exactly (numerically if necessary) a MO_n cluster containing the transition-metal atom and its n nearest O atoms (for example a CoO_6 cluster in the case of the cobaltates, or a CuO_n cluster in the case of the cuprates, in which n depends on the number of apical O atoms), and mapping them into many-body states of the same symmetry containing d holes only. We illustrate the procedure for the case of Na_xCoO_2. The resulting H_eff, including a trigonal distortion D, has been studied recently and its electronic structure agrees well with angle-resolved photoemission spectra [A. Bourgeois, A. A. Aligia, and M. J. Rozenberg, Phys. Rev. Lett. 102, 066402 (2009)]. Although H_eff contains only 3d t_2g holes, the highly correlated states that they represent contain an important amount not only of O 2p holes but also of 3d e_g holes. When more holes are added, a significant redistribution of charge takes place. As a consequence of these facts, the resulting values of the effective interactions between t_2g states are smaller than previously assumed, rendering more important the effect of D in obtaining only one sheet around the center of the Brillouin zone for the Fermi surface (without additional pockets).Comment: 11 pages, 1 figure, accepted for publication in Phys.Rev.