Historical forest biomass dynamics modelled with Landsat spectral trajectories

Acknowledgements National Forest Inventory data are available online, provided by Ministerio de Agricultura, Alimentación y Medio Ambiente (España). Landsat images are available online, provided by the USGS.Peer reviewedPostprin

Laboratory Measurements Of White Dwarf Photospheric Spectral Lines: H Beta

We spectroscopically measure multiple hydrogen Balmer line profiles from laboratory plasmas to investigate the theoretical line profiles used in white dwarf (WD) atmosphere models. X-ray radiation produced at the Z Pulsed Power Facility at Sandia National Laboratories initiates plasma formation in a hydrogen-filled gas cell, replicating WD photospheric conditions. Here we present time-resolved measurements of H beta and fit this line using different theoretical line profiles to diagnose electron density, n(e), and n = 2 level population, n2. Aided by synthetic tests, we characterize the validity of our diagnostic method for this experimental platform. During a single experiment, we infer a continuous range of electron densities increasing from n(e) similar to 4 to similar to 30 x 10(16) cm(-3) throughout a 120-ns evolution of our plasma. Also, we observe n(2) to be initially elevated with respect to local thermodynamic equilibrium (LTE); it then equilibrates within similar to 55 ns to become consistent with LTE. This supports our electrontemperature determination of T-e similar to 1.3 eV (similar to 15,000 K) after this time. At n(e) greater than or similar to 10(17) cm(-3), we find that computer-simulation-based line-profile calculations provide better fits (lower reduced chi(2)) than the line profiles currently used in the WD astronomy community. The inferred conditions, however, are in good quantitative agreement. This work establishes an experimental foundation for the future investigation of relative shapes and strengths between different hydrogen Balmer lines.Laboratory Directed Research and Development programUnited States Department of Energy DE-AC04-94AL85000, DE-SC0010623National Science Foundation DGE-1110007Astronom

Design and fabrication of chemically robust three-dimensional microfluidic valves

A current problem in microfluidics is that poly(dimethylsiloxane) (PDMS), used to fabricate many microfluidic devices, is not compatible with most organic solvents. Fluorinated compounds are more chemically robust than PDMS but, historically, it has been nearly impossible to construct valves out of them by multilayer soft lithography (MSL) due to the difficulty of bonding layers made of non-stick fluoropolymers necessary to create traditional microfluidic valves. With our new three-dimensional (3D) valve design we can fabricate microfluidic devices from fluorinated compounds in a single monolithic layer that is resistant to most organic solvents with minimal swelling. This paper describes the design and development of 3D microfluidic valves by molding of a perfluoropolyether, termed Sifel, onto printed wax molds. The fabrication of Sifel-based microfluidic devices using this technique has great potential in chemical synthesis and analysis

Quantitative Decoding of Interactions in Tunable Nanomagnet Arrays Using First Order Reversal Curves

To develop a full understanding of interactions in nanomagnet arrays is a persistent challenge, critically impacting their technological acceptance. This paper reports the experimental, numerical and analytical investigation of interactions in arrays of Co nanoellipses using the first-order reversal curve (FORC) technique. A mean-field analysis has revealed the physical mechanisms giving rise to all of the observed features: a shift of the non-interacting FORC-ridge at the low-H$_c$ end off the local coercivity H$_c$ axis; a stretch of the FORC-ridge at the high-H$_c$ end without shifting it off the H$_c$ axis; and a formation of a tilted edge connected to the ridge at the low-H$_c$ end. Changing from flat to Gaussian coercivity distribution produces a negative feature, bends the ridge, and broadens the edge. Finally, nearest neighbor interactions segment the FORC-ridge. These results demonstrate that the FORC approach provides a comprehensive framework to qualitatively and quantitatively decode interactions in nanomagnet arrays.Comment: 19 pages, 4 figures. 9 page supplemental material including 3 figure

Spin Asymmetry and Gerasimov-Drell-Hearn Sum Rule for the Deuteron

An explicit evaluation of the spin asymmetry of the deuteron and the associated GDH sum rule is presented which includes photodisintegration, single and double pion and eta production as well. Photodisintegration is treated with a realistic retarded potential and a corresponding meson exchange current. For single pion and eta production the elementary operator from MAID is employed whereas for double pion production an effective Lagrangean approach is used. A large cancellation between the disintegration and the meson production channels yields for the explicit GDH integral a value of 27.31 $\mu$b to be compared to the sum rule value 0.65 $\mu$b.Comment: 4 pages, 5 figures, revtex

Sketch-To-Solution: An Exploration of Viscous CFD with Automatic Grids

Numerical simulation of the Reynolds-averaged NavierStokes (RANS) equations has become a critical tool for the design of aerospace vehicles. However, the issues that affect the grid convergence of three dimensional RANS solutions are not completely understood, as documented in the AIAA Drag Prediction Workshop series. Grid adaption methods have the potential for increasing the automation and discretization error control of RANS solutions to impact the aerospace design and certification process. The realization of the CFD Vision 2030 Study includes automated management of errors and uncertainties of physics-based, predictive modeling that can set the stage for ensuring a vehicle is in compliance with a regulation or specification by using analysis without demonstration in flight test (i.e., certification or qualification by analysis). For example, the Cart3D inviscid analysis package has automated Cartesian cut-cell gridding with output-based error control. Fueled by recent advances in the fields of anisotropic grid adaptation, error estimation, and geometry modeling, a similar work flow is explored for viscous CFD simulations; where a CFD application engineer provides geometry, boundary conditions, and flow parameters, and the sketch-to-solution process yields a CFD simulation through automatic, error-based, grid adaptation

Performance Analysis of FBMC and CP-OFDM in the Presence of Phase Noise

Multi-Carrier (MC) modulation schemes like Or- thogonal Frequency Division Multiplexing (OFDM) are highly sensitive to Phase Noise (PN). In the case of air interfaces operating in higher frequencies, e.g. the range between 6 and 100 GHz frequently called millimeter wave (mmWave), the PN generated by the local oscillators is even more accentuated. Alternative MC systems are being considered for future mmWave wireless communications. In this contribution, we analytically derive expressions for an upper bound for the interference power generated by the PN in OFDM, DFT-Spread-OFDM and Filter Bank Multi-Carrier (FBMC). Then, we evaluate the performance degradation due to that imperfection in terms of coded and uncoded BER

The Vinylguaiacol/Indole or VGI ( Veggie ) Ratio: A Novel Molecular Parameter to Evaluate the Relative Contributions of Terrestrial and Aquatic Organic Matter to Sediments.

The organic matter (OM) fraction of estuarine sediments is often distinctive and thus diagnostically useful in determinations of sedimentary provenance. Among the most fundamental distinctions to be made is that between terrestrial and aquatic OM. To supplement the parameters commonly used for this purpose (e.g., C/N and stable isotope ratios), we proposed the Vinylguaiacol/Indole or VGI ( Veggie ) ratio, defined as [vinylguaiacol / (indole + vinylguaiacol)] using data produced by analytical pyrolysis-gas chromatography/mass spectrometry of dried, homogenized sediment samples. The ratio employs the peak areas of these two compounds on the mass chromatograms of their molecular ions (m/z 150 and 117). Major pyrolysis products of terrestrial plant lignin include a variety of methoxyphenols, notably 4-vinylguaiacol. In contrast, aquatic algae and bacteria characteristically produce distinctive organonitrogen compounds upon pyrolysis, particularly indole, derived from the amino acid tryptophan. The end member VGI ratio value of 1.00 is obtained for reference land plant matter, including the marsh plants Phragmites and Spartina, as well as maple and pine wood. The end member value of 0.00 is obtained for cultured microbes, including Escherichia coli and the cyanobacterium Anacystis. Vinylguaiacol and indole are commonly detected in Recent sediment pyrolyzates. We hypothesized that their relative quantities therein should be proportional to the relative contributions of land plant and microbial OM, respectively. Samples taken from Spartina peat marshes at the mouths of major rivers (Housatonic and Connecticut) entering Long Island Sound, wetlands behind the barrier island at Cape May (NJ), and a Phragmites-dominated tidal marsh along the Hackensack River (NJ) have high (\u3e 0.8) VGI ratio values. Sediments collected within the Newark Bay (NJ) estuary from the lower Passaic and Hackensack Rivers and the Arthur Kill show mixed terrestrial and aquatic OM signatures (VGI from 0.3 to 0.7, generally increasing upstream). Jamaica Bay (NY), behind an Atlantic barrier island and with marsh islands and multiple urbanized tidal creeks, displays a very wide VGI range, affected by proximity to stands of marsh vegetation, bathymetry, and sediment grain size. Sediments from New Haven (CT) harbor show a diminution in VGI values from 0.66 at the mouth of the Quinnipiac River to 0.08 at the entrance to the harbor over a distance of only 4 km, as terrestrial influences wane moving towards open water. Deep water Long Island Sound sediments show a strong predominance of aquatic OM (VGI about 0.05), while nearshore sediments collected 2 km from the mouth of the Housatonic River and in embayments near the Connecticut and Thames River mouths have a greater terrestrial OM component (VGI of 0.15 to 0.23). The results demonstrate a precipitous decrease in the relative amounts of unaltered land plant OM in the offshore direction, but also that a minor fraction persists in deeper water environments

The Vinylguaiacol/Indole or VGI ( Veggie ) Ratio: Assessing Relative Contributions of Terrestrial and Aquatic Organic Matter to Sediments

In studies of the organic matter (OM) fraction of marine, estuarine, fluvial, or lacustrine sediments, one of the most fundamental distinctions to be made is that between terrestrial and aquatic OM. To supplement the parameters commonly used for this purpose (e.g., C/N and stable isotope ratios), we proposed the Vinylguaiacol/Indole or VGI ( Veggie ) ratio, defined as [vinylguaiacol / (indole + vinylguaiacol)] using data produced by analytical pyrolysis-gas chromatography/mass spectrometry of dried, homogenized sediment samples [1]. The ratio employs the peak areas of these two compounds on the mass chromatograms of their molecular ions (m/z 150 and 117, respectively). Major pyrolysis products of terrestrial plant lignin include a variety of methoxyphenols, notably 4-vinylguaiacol. In contrast, aquatic algae and bacteria characteristically produce distinctive organonitrogen compounds upon pyrolysis, particularly indole, derived from the amino acid tryptophan. The end member VGI ratio value of 1.00 is nearly obtained for reference land plant matter, such as maple wood (Fig. 1d). The end member value of 0.00 is obtained for cultured microbes, including Escherichia coli (Fig. 1a). Vinylguaiacol and indole are commonly detected in Recent sediment pyrolysates. We hypothesized that their relative quantities therein should be proportional to the contributions of land plant and aquatic OM, respectively [1]. While soil microbes in terrestrial OM would lead to a diminution of VGI values, stable isotope and C/N ratios would likely be similarly perturbed. Systematic variations in VGI ratio values are observed among estuarine sediments from southern New York and New England (USA). Samples taken from Spartina peat marshes at the mouths of major rivers entering Long Island Sound have high (\u3e 0.8) VGI ratio values. Jamaica Bay (New York), behind an Atlantic barrier island and with marsh islands and multiple urbanized tidal creeks, displays a very wide VGI range (Fig. 1b,c), affected by proximity to stands of marsh vegetation, bathymetry, and sediment grain size. Sediments from New Haven (Connecticut) harbour show a diminution in VGI values from 0.66 at the mouth of a river in the innermost harbour to 0.08 at the harbour entrance over a distance of only 4 km, as terrestrial influences wane moving towards open water. In Long Island Sound, deep water sediments show a strong predominance of aquatic OM (VGI about 0.05), while nearshore sediments collected close to the mouths of rivers have a greater terrestrial OM component (VGI of 0.15 to 0.23). The results demonstrate a precipitous decrease in the relative amounts of unaltered land plant OM in the offshore direction, but also that a minor fraction persists in deeper water environments. [1] Micic et al., 2010, Org. Geochem. 41:971-974