Spreading Of Plume Research Articles

A modelling investigation of solute transport in permeable porous media containing a discrete preferential flow feature

Preferential flow features (PFFs, e.g. fractures and faults) are common features in rocks that otherwise have significant matrix permeability. Despite this, few studies have explored the influence of a PFF on the distribution of solute plumes in permeable rock formations, and the current understanding of PFF effects on solute plumes is based almost entirely on low-permeability rock matrices. This research uses numerical modelling to examine solute plumes that pass through a PFF in permeable rock, to explore the PFF's influence on plume migration. The study adopts intentionally simplified arrangements involving steady-state solute plumes in idealised, moderate-to-high-permeability rock aquifers containing a single PFF. A range of matrix-PFF permeability ratios (4.9×10−6–2.5×10−2), typical of fractured sedimentary aquifers, is considered. The results indicate that for conditions representative of high-to-moderate-permeability sedimentary rock matrices containing a medium-sized fracture, the effect of the PFF on solute plume displacement and spreading can be considerable. For example, plumes are between 1.3 and 19 times wider than in associated porous media only scenarios, and medium-sized PFFs in moderately permeable matrices can reduce the maximum solute concentration by up to 104 times. Plume displacement and spreading is lower in aquifers of higher matrix-PFF permeability ratios, and where solute plumes are more dispersed at the point of intersection with the PFF. Asymmetry in the plume caused by the passage through the PFF is more pronounced for more dispersive plumes. The current study demonstrates that PFFs most likely govern solute plume characteristics in typical permeable matrices, given that a single PFF of aperture representing a medium-sized fracture (i.e. 5.0×10−4m) produces the equivalent spreading effects of 0.22–7.88m of plume movement through the permeable matrix.

Project Sagebrush: Revisiting the Value of the Horizontal Plume Spread Parameter σy

AbstractThe first phase of an atmospheric tracer experiment program, designated Project Sagebrush, was conducted at the Idaho National Laboratory in October 2013. The purpose was to reevaluate the results of classical field experiments in short-range plume dispersion (e.g., Project Prairie Grass) using the newer technologies that are available for measuring both turbulence levels and tracer concentrations. All releases were conducted during the daytime with atmospheric conditions ranging from neutral to unstable. The key finding was that the values of the horizontal plume spread parameter σy tended to be larger, by up to a factor of ~2, than those measured in many previous field studies. The discrepancies tended to increase with downwind distance. The values of the ratio σy/σθ, where σθ is the standard deviation of the horizontal wind direction, also trend near the upper limit or above the range of values determined in earlier studies. There was also evidence to suggest that the value of σy began to be independent of σθ for σθ greater than 18°. It was also found that the commonly accepted range of values for σθ in different stability conditions might be limiting, at best, and might possibly be unrealistically low, especially at night in low wind speeds. The results raise questions about the commonly accepted magnitudes of σy derived from older studies. These values are used in the parameterization and validation of both older stability-class dispersion models as well as newer models that are based on Taylor’s equation and modern PBL theory.

Looking ahead: What’s on the horizon for drones?

As researchers envisage new ways to use drones as flying laboratories, others are tinkering with their robotic insides, trying to make them smaller, faster, and safer. Many drone engineers are intent on designing flying robots to be more autonomous so that they can perform tasks without a pilot. Imagine, for example, drones capable of quickly mapping collapsed buildings to help search-and-rescue personnel find trapped victims or identify looming threats such as a fire or gas leak, says Vijay Kumar, who is developing this technology at the University of Pennsylvania. Others are working to improve communication between drones so that swarms of these flying machines can accomplish tasks that a single unmanned aerial vehicle could not achieve alone. Researchers could, for instance, deploy a flock of flying sensors to track the edges of a suspicious airborne plume spreading across the sky in real time, says Kam K. Leang, director of the

Can We Predict How Volcanic Ash Disperses After an Eruption?

Researchers investigate what factors influence how particles from a plume spread following a volcanic eruption.

Impact of a flood event on the zooplankton of an estuarine lake

ABSTRACTShallow coastal lakes are prone to large fluctuations in physico-chemical variables such as salinity and turbidity. This is now escalating in response to global change. A flood event in March 2014 resulted in a silt plume spreading through part of Lake St Lucia (South Africa). To determine the impact of this event on zooplankton, the Narrows region of St Lucia was sampled on a monthly basis from March to September 2014. For comparative purposes, data from samples collected prior to the flood event were included in the analyses. Analysis of similarity (ANOSIM) revealed dissimilarities in zooplankton community structure among the sampling occasions. The March 2014–May 2014 period was characterized by the highest abundance of freshwater species. Conversely, the abundance of the resident St Lucia copepods Acartiella natalensis and Oithona brevicornis was lowest during this time, and highest in September 2014. The other dominant copepod Pseudodiaptomus stuhlmanni prevailed in March 2014, but declined markedly in April. As of September 2014, P. stuhlmanni had yet to regain its pre-flood densities. The BIOENV procedure, which relates biological and environmental data, revealed that turbidity, salinity and dissolved oxygen were responsible for the observed changes in zooplankton community structure during the study period. Careful management of turbidity and salinity is stressed, as both factors are major drivers of the biota of St Lucia and similar systems worldwide.

Influence of Physicochemical Factors on Biodiesel Retention in Clayey Residual Soil

AbstractSoil can naturally attenuate contamination, depending on its interaction with contaminants. Soils can delay the spread of the contaminant plume and even reduce the bioavailability of the contaminant because of their contaminant retention capacity. The retention capacity may be influenced by several physicochemical factors of both the soil and the contaminant. The aim of this study was to assess the retention capacity of a clayey, basaltic residual soil to an organic contaminant (soybean biodiesel) under different variable conditions, such as moisture content, void ratio, and presence or absence of biostimulation nutrients, specifically nitrogen (N), phosphorus (P), and potassium (K). Experiments were conducted using 100-g samples of dry soil under different void ratios (1.14, 1.24, and 1.34) and different moisture contents (15, 25, and 35%). Two series of experiments were conducted: one in the absence of nutrients and another in the presence of nutrients. The soil samples were initially sterilized...

Analysis on the Influence of Fire Overhangs on the Window to Exterior Wall Vertical Fire Plume Spreading under External Wind

The blocked performance of the fire canopy to vertical fire plume spread was studied by 1/2 scale building external facade flame experiment and FDS numerical simulation, and the blocked performance of the fire canopy to vertical fire plume spread was studied under external wind by FDS. The results showed that when the extending length of the fire canopy reached 0.6 m, it could block the vertical spread of openings overflow fire plume effectively; when the wind speed reached 3 m/s, the height of windowsill walls reached 0.4 m, the fire canopy could still block vertical fire plume spread.

Vertical segregation of age-0 and age-1+ polar cod (Boreogadus saida) over the annual cycle in the Canadian Beaufort Sea

The offshore marine ecosystem of the Canadian Beaufort Sea faces the double pressure of climate change and industrialization. Polar cod (Boreogadus saida) is a pivotal forage species in this ecosystem, accounting for 95 % of the pelagic fish assemblage. Its vertical distribution over the annual cycle remains poorly documented. Hydroacoustic records from 2006 to 2012 were analysed to test the hypothesis that age-0 polar cod segregate vertically from larger congeners. Trawls and ichthyoplankton nets validated the acoustic signal. Fish length, weight, and biomass were estimated from new regressions of target strength and weight on standard length. Polar cod were vertically segregated by size in all months, with small age-0 juveniles in the epipelagic (<100 m) layer and larger age-1+ deeper in the water column. From December to March, the biomass of age-1+ peaked in a mesopelagic layer between 200 and 400 m. With increasing irradiance from April to July, the mesopelagic layer deepened and extended to 600 m. Starting in July, age-0 polar cod formed an epipelagic scattering layer that persisted until November. From September onward, age-0 left the epipelagic layer to join small age-1+ in the upper mesopelagic layer. Low biomass in the mesopelagic layer from February to September likely resulted from large polar cod settling on the seafloor to avoid diving marine mammals. Longer ice-free seasons, warmer sea-surface temperatures, or an oil spill at the surface would likely impact epipelagic age-0, while mesopelagic age-1+ would be vulnerable to an eventual oil plume spreading over and above the seafloor.

Equivalent Porous Media (EPM) Simulation of Groundwater Hydraulics and Contaminant Transport in Karst Aquifers.

Karst aquifers have a high degree of heterogeneity and anisotropy in their geologic and hydrogeologic properties which makes predicting their behavior difficult. This paper evaluates the application of the Equivalent Porous Media (EPM) approach to simulate groundwater hydraulics and contaminant transport in karst aquifers using an example from the North Coast limestone aquifer system in Puerto Rico. The goal is to evaluate if the EPM approach, which approximates the karst features with a conceptualized, equivalent continuous medium, is feasible for an actual project, based on available data and the study scale and purpose. Existing National Oceanic Atmospheric Administration (NOAA) data and previous hydrogeological U. S. Geological Survey (USGS) studies were used to define the model input parameters. Hydraulic conductivity and specific yield were estimated using measured groundwater heads over the study area and further calibrated against continuous water level data of three USGS observation wells. The water-table fluctuation results indicate that the model can practically reflect the steady-state groundwater hydraulics (normalized RMSE of 12.4%) and long-term variability (normalized RMSE of 3.0%) at regional and intermediate scales and can be applied to predict future water table behavior under different hydrogeological conditions. The application of the EPM approach to simulate transport is limited because it does not directly consider possible irregular conduit flow pathways. However, the results from the present study suggest that the EPM approach is capable to reproduce the spreading of a TCE plume at intermediate scales with sufficient accuracy (normalized RMSE of 8.45%) for groundwater resources management and the planning of contamination mitigation strategies.

Relationships between environmental features, distribution and abundance of the Argentine anchovy, Engraulis anchoita, on the South West Atlantic Continental Shelf

Marine fisheries in Brazil follow a similar trend as the rest of the world, with reduced catches of most stocks. Although extensive, the Brazilian coast is poorly assessed, and marine fishery resources are not properly managed. Small pelagic fishes are secondary consumers, which feed on zooplankton and serve as foraging species for large, carnivorous fishes. The anchovy (Engraulis anchoita) is an abundant, small pelagic fish found in abundance in Brazilian waters as it migrates along the Brazilian, Uruguayan and Argentine shelves. In 2010, five acoustic assessment cruises were conducted to estimate anchovy biomass in the southernmost part of the Brazilian coast. Hydroacoustic data were obtained using a SIMRAD EK 500 echo sounder along parallel transects. CTD (conductivity temperature depth) casts and mid-water trawl hauls were used to collect environmental and biological data. Anchovy biomass was estimated using NASC values, the fish target strength by size and the dimension of the surveyed area. For each survey, a GLM binomial was fitted to anchovy presence and the following explanatory variables: surface salinity and temperature, bottom salinity and temperature, and depth. Anchovy biomass ranged between 73,000 (June) and 814,000 (August) tons. We observed a mean temperature decrease of ∼3°C during the June and August surveys. This sharp environmental change was followed by a distinct increase in adult anchovy biomass from the first to the second survey. Fitted GLM models indicated that the bottom layers of cold, saline water had a positive effect on anchovy presence in August but not in June. Furthermore, during the August survey, a sharp change in the surface layer waters was observed on the Southern Brazilian Shelf, as the result of a low-salinity water inflow to this area. This phenomena was due to the Patos Lagoon runoff and also to the coastal winds over the Argentine Shelf, which forces the northward spreading of the Plate River plume to lower latitudes. This inflow increases primary productivity and, subsequently, the occurrence of fishes within the area.

Estimation of point source fugitive emission rates from a single sensor time series: A conditionally-sampled Gaussian plume reconstruction

Emerging mobile fugitive emissions detection and measurement approaches require robust inverse source algorithms to be effective. Two Gaussian plume inverse approaches are described for estimating emission rates from ground-level point sources observed from remote vantage points. The techniques were tested using data from 41 controlled methane release experiments (14 studies) and further investigated using 7 field studies executed downwind of oil and gas well pads in Wyoming. Analyzed measurements were acquired from stationary observation locations 18–106 m downwind of the emission sources. From the fluctuating wind direction, the lateral plume geometry is reconstructed using a derived relationship between the wind direction and crosswind plume position. The crosswind plume spread is determined with both modeled and reconstructed Gaussian plume approaches and estimates of source emission rates are found through inversion. The source emission rates were compared to a simple point source Gaussian emission estimation approach that is part of Draft EPA Method OTM 33A. Compared to the known release rates, the modeled, reconstructed, and point source Gaussian controlled release results yield average percent errors of −5%, -2%, and 6% with standard deviations of 29%, 25%, and 37%, respectively. Compared to each other, the three methods agree within 30% for 78% of all 48 observations (41 CR and 7 Wyoming).

Understanding the carbon dioxide sequestration in low‐permeability saline aquifers in the Ordos Basin with numerical simulations

AbstractA carbon dioxide (CO2) capture and storage demonstration project was started in 2010 by injecting around 100 000 tonnes of super‐critical CO2 per annum into a set of very low‐permeability sandstone at depths of more than 1600 m in the northeastern Ordos Basin, China. Based on the site‐specific geology and the observational data, a numerical injection model was developed in order to understand the hydrodynamic behavior of CO2 in the subsurface for evaluating reservoir performance. The results show that the model reasonably described the spreading of the CO2 plume. The Triassic Liujiagou sandstone aquifer is the most favorable storage formation for CO2 sequestration at the site of interest. After three years of injection of CO2, the maximum lateral migration distance of CO2 plume is about 550 m and the pressure build‐up is about 13 MPa in the Liujiagou formation for the actual injection simulation. The major storage layer is at depths of 1690–1699 m, which contributes around 80% of injectivity of the entire reservoir system. The leakage of CO2 into the geological seals is negligible (&lt;0.1%) over the entire simulation period. Regardless of the relatively good fit during the calibration period, the model overestimated the pressures associated with the injection thereafter. © 2015 Society of Chemical Industry and John Wiley &amp; Sons, Ltd

Experimental study on growth and spread of dispersed particle-laden plume in a linearly stratified environment

We present results of laboratory experiments conducted to study the evolution, growth, and spreading rate of a dispersed particle-laden plume produced by a constant inflow into a density varying environment. Particles having mean size, \(d_p=100\ \upmu \)m, density \(\rho _p=2500 \ {\text{ kg/m}}^3\), volume fraction, \(\phi _v =\) 0–0.7 % , were injected along with the lighter buoyant fluid into a linearly stratified medium. It was observed that a particle-laden plume intruding at the neutral density layer is characterized by four spreading regimes: (i) radial momentum flux balanced by the inertia force; (ii) inertia buoyancy regime; (iii) fluid-particle inertia regime, and (iv) viscous buoyancy regime. Regimes (i), (ii), and (iv) are similar to that of a single-phase plume, for which \(\phi _v = 0\,\%\). The maximum height, \(Z_m\), for \(\phi _v > 0\,\%\) was observed to be consistently lower than the single-phase case. An empirical parameterization was developed for the maximum height for particle-laden case, and was found to be in very good agreement with the experimental data. In the inertia buoyancy regime, the radial spread of the plume, \(R_f\), for \(\phi _v > 0\,\%\), advanced in time as \(R_f \propto t^{0.68 \pm 0.02}\) which is slower compared to the single-phase plume that propagates at \(R_f \propto t^{0.74 \pm 0.02}\). Due to the presence of particles, ‘particle fall out’ effect occurs, which along with the formation of a secondary umbrella region inhibits the spreading rate and results in slower propagation of the particle-laden plume. The effect of particles on spreading height of plume, \(Z_s\), and thickness of the plume, \(h_p\), were also studied, and these results were compared with the single-phase case. Overall from these experiments, it was found that the evolution, growth, and spread of dispersed particle-laden plume is very different from that of the single-phase plume, and presence of low concentration of particles (\( \phi _v < 1\,\%\)) could have significant effects on the plume dynamics.

Numerical and experimental study of horizontal round turbulent forced plume in a static homogeneous environment

This paper investigates a numerical and experimental study about horizontal round turbulent forced plume injected into a static homogeneous environment. Helium–air plume is an example of non-Boussinesq forced plume in which a low-density binary gas mixture is injected into a high density ambient of air. Since the domain temperature is assumed to be constant, the density of the mixture is a function of the concentration only. Numerical model is based on the finite volume method and reports on an application of standard k–e model for steady flow with densimetric Froude numbers of 30–300 and Reynolds numbers of 2000–6000. The basic features of the model are: the conservation of mass, momentum and concentration. The boundaries of plume body, the centerline trajectory, the radius plume and the centerline mixture density are determined. It is found that the plume spreading and behavior depend on the ratio between buoyancy flux and momentum, i.e. Froude number. Laboratory experiments have been conducted for photographic observations of plumes trajectories for different mixture (helium–air) densities with different velocities and injection nozzle diameters. Numerical results are described and compared with the experiments and good agreement has been achieved.

Leachate transport through advection-diffusion and linear sorption in saturated land

A long-term large-scale variably-saturated subsurface numerical solution of flow and transport are conducted and presented as a simple and fast computational method. Therefore, it is appropriate to develop such a simplified model that focus on the main processes operating at the pertinent time and space scales, based on the error introduced by the simpler model which is acceptable and also was compared to the uncertainties associated with the spatial and temporal variation of boundary conditions. To assess leachate transport as contamination potential it requires calculation of drainage water volume and contamination concentration. A practical, quantitative pollution transfer assessment tool can be developed to enable technical service providers and other practitioners to estimate potential pollution transfer and design best management practices for land waste management pollution systems in order to estimate and control pollution transport to soil and groundwater. The objective of this paper is to describe governing numerical equation and solution algorithm of pollution transport mechanisms and also essential factors which are included in developing relatively simple and practical tools to quantify pollution loss, advection, diffusion and sorption in pollution transport into the groundwater at landfill sites. The paper presents the development of a two-dimensional numerical model that can be used for quantifying groundwater inputs and associated contaminant discharge from a landfill into the affected aquifer. The presented computing results reveal that the proposed model can be used for the simulation of contaminant transport in aquifers in any scale. This numerical solution is established on finite difference, finite-volume solution advection-diffusion linear sorption with first order decay equation. To show the capability of proposed model, the results of a case study are presented in the paper as simulating leachate transport at a 2000 ton/day landfill facility assesses leachate migration away from the landfill in order to control associated environmental impacts, particularly on groundwater wells gradient of the site. Leachate discharge from landfills is the main route for release of the organic and inorganic contaminants through subsurface, commonly encountered in the refuse. Leachate quantity and potential percolation into the subsurface are estimated by the proposed model. A comprehensive sensitivity analysis to leachate transport control parameters was also conducted. Sensitivity analysis suggest that changes in source strength, aquifer hydraulic conductivity, and dispersivity have the most significant impact on model output indicating that these parameters should be carefully selected when similar modeling studies are performed. The sensitivity of the model to variations in input parameters results in two opposing patterns of contaminant concentration. While higher groundwater velocities increase the speed of plume spread it also increases the dilution ratio and hence decrease the concentration.

The Spreading of a Buoyant Plume Beneath a Landfast Ice Cover

AbstractIdealized numerical simulations using the Regional Ocean Modeling System demonstrate the effects of an immobile landfast ice cover that is frictionally coupled to an underice buoyant plume established by river discharge. The discharge rapidly increases and decreases over a 30-day period and has a maximum of 6000 m3 s−1. This study examined the response to a landfast ice cover of 26-km width and one that encompasses the entire shelf width. The model setting mimics spring conditions on the Alaskan Beaufort Sea (ABS) shelf. In comparison with the ice-free case subject to the same discharge scenario, underice plumes are broader and deeper, and the downwave freshwater flux is substantially decreased and delayed. Multiple anticyclonic bulges form in the ice-free case, but only a single, large bulge forms when ice is present. These differences are because of the frictional coupling between the ice and plume, which results in an Ekman-like underice boundary layer, a subsurface velocity maximum, and frictional shears that enhance vertical mixing and entrainment. For a partially ice-covered shelf, the plume spreads across the ice edge to form a swift, buoyant, ice-edge jet, whose width accords with the scale of Yankovsky and Chapman for a surface-advected plume. For a fully ice-covered shelf, the buoyant water spreads 60 km offshore over a 30-day period. For a steady discharge of 6000 m3 s−1 and a completely ice-covered shelf, the plume spreads offshore at a rate of ~1.5 km day−1 and extends ~95 km offshore after 60 days.

Wind forcing controls on river plume spreading on a tropical continental shelf

AbstractThe Berau Continental Shelf is located close to the Equator in the Indonesian Archipelago, hosting a complex of coral reefs along its oceanic edge. The Berau coral reefs have a very high biodiversity, but the area is under serious risk due to river‐derived nutrients and sediments. The region is characterized by weak winds, moderate tides, and almost absent Coriolis forcing. Existing knowledge about river plume behavior in tropical environments is limited. The aim of this paper is to investigate the influence of the subtle physical forcing on the dynamics of the Berau river plume. A three‐dimensional model (ECOMSED) was calibrated with observational data. The model was forced by freshwater input from the Berau river distributaries, tides at the open boundaries, and measured hourly wind. The model reproduces the freshwater dynamics on the shelf adequately and highlights that the river plume spreads symmetrically for river forcing only. Tides cause vertical mixing and suppress the cross‐shelf spreading of the river plume. However, the spreading of the river plume over the shelf is mainly controlled by the weak monsoonal winds, resulting in a seasonal development. During the Southeast Monsoon, the southerly winds push the plume northeastward and cause a stratified water column in the northern part of the continental shelf. Northerly winds during the Northwest Monsoon disperse the plume to the south, promoting a vertically well‐mixed water column. The results can be used to predict the possible impact of land‐use changes in the steadily developing Berau region on coral reef health.

Monitoring the spreading of the Amazon freshwater plume by MODIS, SMOS, Aquarius, and TOPAZ

AbstractA synergistic tool for studying the Amazon River plume dynamics based on a novel algorithm for deriving sea surface salinity (SSS) from MODIS reflectance data together with SSS data from the SMOS and Aquarius satellites and the TOPAZ data assimilation system is proposed. The new algorithm is based on a neural network to relate spectral remote sensing reflectance measured by MODIS with SSS measured by SMOS in the Amazon River plume. The algorithm is validated against independent in situ data and is found to be valid in the range of SSS from 29 to 35 psu, for the period of highest rates of Amazon River discharge with RMSE = 0.79 psu and r2 = 0.84. Monthly SSS fields were reconstructed from the MODIS data for late summers from 2002 to 2012 at a 10 km resolution and compared to surface currents and SSS derived from the TOPAZ reanalysis system. The two data sets reveal striking agreement, suggesting that the TOPAZ system could be used for a detailed study of the Amazon River plume dynamics. Both the position and speed of the North Brazilian Current as well as the spreading of the Amazon River plume are monitored. In particular, a recurrent mechanism was observed for the spreading of the rivers plumes, notably that the fresh water is usually advected toward the Caribbean Sea by the North Brazilian Current but get diverted into the tropical Atlantic when North Brazilian Current Rings are shed.

Small scale monitoring of a bioremediation barrier using miniature electrical resistivity tomography

The aim of this study was to assess, in the laboratory, the efficiency of a barrier of oxygen release compound (ORC) to block and divert a diesel plume migration in a scaled aquifer model using miniature electrical resistivity tomography (ERT) as the monitoring system. Two plumes of contaminant (diesel) were injected in a soil model made of local sand and clay. The diesel plumes migration was imaged and monitored using a miniature resistivity array system that has proved to be accurate in soil resistivity variations in small-scaled models of soil. ERT results reflected the lateral spreading and diversion of the diesel plumes in the unsaturated zone. One of the contaminant plumes was partially blocked by the ORC barrier and a diversion and reorganisation of the diesel in the soil matrix was observed. The technique of time-lapse ERT imaging showed that a dense non-aqueous phase liquid (DNAPL) contaminant like diesel can be monitored through a bioremediation barrier and the technique is well suited to monitor the efficiency of the barrier. Therefore, miniature ERT as a small-scale modelling tool could complement conventional techniques, which require more expensive and intrusive site investigation prior to remediation.

Laser ablation sample transfer for mass spectrometry imaging.

Infrared laser ablation sample transfer (IR-LAST) is a novel ambient sampling technique for mass spectrometry. In this technique, a pulsed mid-IR laser is used to ablate materials that are collected for mass spectrometry analysis; the material can be a solid sample or deposited on a sample target. After collection, the sample can be further separated or analyzed directly by mass spectrometry. For IR-LAST sample transfer tissue imaging using MALDI mass spectrometry, a tissue section is placed on a sample slide and material transferred to a target slide by scanning the tissue sample under a focused laser beam using transmission-mode (back side) IR laser ablation. After transfer, the target slide is analyzed using MALDI imaging. The spatial resolution is approximately 400 μm and limited by the spread of the laser desorption plume. IR-LAST for MALDI imaging provides several new capabilities including ambient sampling, area to spot concentration of ablated material, multiple ablation and analysis from a single section, and direct deposition on matrix-free nanostructured targets.