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Sample records for air parcel model

  1. Air parcel random walk and droplet spectra broadening in clouds.

    PubMed

    Turitsyn, K S

    2003-06-01

    We study the effect of turbulent flow on the droplet growth in a cloud during the condensation phase. Using the air parcel model, we describe analytically how the size distribution of droplets evolves at the different stages of parcel movement. We show that turbulent random walk superimposed on an accelerated ascent of the parcel makes the relative width of droplet distribution to grow initially as t(1/2) and then decay as t(-3/2).

  2. New particle-dependent parameterizations of heterogeneous freezing processes: sensitivity studies of convective clouds with an air parcel model

    NASA Astrophysics Data System (ADS)

    Diehl, K.; Mitra, S. K.

    2015-11-01

    Based on the outcome of laboratory results, new particle-dependent parameterizations of heterogeneous freezing were derived and used to improve and extend a two-dimensional spectral microphysics scheme. They include (1) a particle-type-dependent parameterization of immersion freezing using the numbers of active sites per mass, (2) a particle-type and size-resolved parameterization of contact freezing, and (3) a particle-type-dependent description of deposition freezing. The modified microphysical scheme was embedded in an adiabatic air parcel model with entrainment. Sensitivity studies were performed to simulate convective situations and to investigate the impact of ice nuclei concentrations and types on ice formation. As a central diagnostic parameter, the ice water fraction (IWF) was selected, which is the relation of the ice water content to the total amount of water in the condensed form. The following parameters were varied: initial aerosol particle number size distributions, types of ice nucleating particles, final temperature, and the fractions of potential ice nucleating particles. Single and coupled freezing processes were investigated. The results show that immersion freezing seems to be the most efficient process. Contact freezing is constrained by the collision kernel between supercooled drops and potential ice nucleating particles. The importance of deposition freezing lies in secondary ice formation; i.e., small ice particles produced by deposition nucleation trigger the freezing of supercooled drops by collisions. Thus, a broader ice particle spectrum is generated than that by immersion and contact freezing. During coupled immersion-contact and contact-deposition freezing no competition was observed, and both processes contribute to cloud ice formation but do not impede each other. As already suggested in the literature, mineral dust particles seem to be the most important ice nucleating particles. Biological particles are probably not involved in

  3. Mathematical Model of Evolution of Brain Parcellation.

    PubMed

    Ferrante, Daniel D; Wei, Yi; Koulakov, Alexei A

    2016-01-01

    We study the distribution of brain and cortical area sizes [parcellation units (PUs)] obtained for three species: mouse, macaque, and human. We find that the distribution of PU sizes is close to lognormal. We propose the mathematical model of evolution of brain parcellation based on iterative fragmentation and specialization. In this model, each existing PU has a probability to be split that depends on PU size only. This model suggests that the same evolutionary process may have led to brain parcellation in these three species. Within our model, region-to-region (macro) connectivity is given by the outer product form. We show that most experimental data on non-zero macaque cortex macroscopic-level connections can be explained by the outer product power-law form suggested by our model (62% for area V1). We propose a multiplicative Hebbian learning rule for the macroconnectome that could yield the correct scaling of connection strengths between areas. We thus propose an evolutionary model that may have contributed to both brain parcellation and mesoscopic level connectivity in mammals. PMID:27378859

  4. Mathematical Model of Evolution of Brain Parcellation

    PubMed Central

    Ferrante, Daniel D.; Wei, Yi; Koulakov, Alexei A.

    2016-01-01

    We study the distribution of brain and cortical area sizes [parcellation units (PUs)] obtained for three species: mouse, macaque, and human. We find that the distribution of PU sizes is close to lognormal. We propose the mathematical model of evolution of brain parcellation based on iterative fragmentation and specialization. In this model, each existing PU has a probability to be split that depends on PU size only. This model suggests that the same evolutionary process may have led to brain parcellation in these three species. Within our model, region-to-region (macro) connectivity is given by the outer product form. We show that most experimental data on non-zero macaque cortex macroscopic-level connections can be explained by the outer product power-law form suggested by our model (62% for area V1). We propose a multiplicative Hebbian learning rule for the macroconnectome that could yield the correct scaling of connection strengths between areas. We thus propose an evolutionary model that may have contributed to both brain parcellation and mesoscopic level connectivity in mammals. PMID:27378859

  5. Cirrus Parcel Model Comparison Project. Phase 1

    NASA Technical Reports Server (NTRS)

    Lin, Ruei-Fong; Starr, David O'C.; DeMott, Paul J.; Cotton, Richard; Jensen, Eric; Sassen, Kenneth

    2000-01-01

    The Cirrus Parcel Model Comparison (CPMC) is a project of the GEWEX Cloud System Study Working Group on Cirrus Cloud Systems (GCSS WG2). The primary goal of this project is to identify cirrus model sensitivities to the state of our knowledge of nucleation and microphysics. Furthermore, the common ground of the findings may provide guidelines for models with simpler cirrus microphysics modules. We focus on the nucleation regimes of the warm (parcel starting at -40 C and 340 hPa) and cold (-60 C and 170 hPa) cases studied in the GCSS WG2 Idealized Cirrus Model Comparison Project. Nucleation and ice crystal growth were forced through an externally imposed rate of lift and consequent adiabatic cooling. The background haze particles are assumed to be lognormally-distributed H2SO4 particles. Only the homogeneous nucleation mode is allowed to form ice crystals in the HN-ONLY runs; all nucleation modes are switched on in the ALL-MODE runs. Participants were asked to run the HN-lambda-fixed runs by setting lambda = 2 (lambda is further discussed in section 2) or tailoring the nucleation rate calculation in agreement with lambda = 2 (exp 1). The depth of parcel lift (800 m) was set to assure that parcels underwent complete transition through the nucleation regime to a stage of approximate equilibrium between ice mass growth and vapor supplied by the specified updrafts.

  6. GCSS Cirrus Parcel Model Comparison Project

    NASA Technical Reports Server (NTRS)

    Lin, Ruei-Fong; Starr, David OC.; DeMott, Paul J.; Cotton, Richard; Jensen, Eric; Sassen, Kenneth; Einaudi, Franco (Technical Monitor)

    2000-01-01

    assumptions that can only be justified by further laboratory data. Consequently, it is not yet clear if the two approaches can be made consistent. Large haze particles may deviate considerably from equilibrium size in moderate to strong updrafts (20-100 cm/s) at -60 C when the commonly invoked equilibrium assumption is lifted. The resulting difference in particle-size-dependent solution concentration of haze particles may significantly affect the ice nucleation rate during the initial nucleation interval. The uptake rate for water vapor excess by ice crystals is another key component regulating the total number of nucleated ice crystals. This rate, the product of ice number concentration and ice crystal diffusional growth rate, which is sensitive to the deposition coefficient when ice particles are small, partially controls the peak nucleation rate achieved in an air parcel and the duration of the active nucleation time period. The effects of heterogeneous nucleation are most pronounced in weak updraft situations. Vapor competition by the nucleated (heterogeneous) ice crystals limits the achieved ice supersaturation and thus suppresses the contribution of homogeneous nucleation. Correspondingly, ice crystal number density is markedly reduced. Definitive laboratory and atmospheric benchmark data are needed for the heterogeneous nucleation process. Inter-model differences are correspondingly greater than in the case of the homogeneous nucleation process acting alone.

  7. Evolution of chemically processed air parcels in the lower stratosphere

    NASA Technical Reports Server (NTRS)

    Stolarski, Richard S.; Douglass, Anne R.; Schoeberl, Mark R.

    1994-01-01

    Aircraft, ground-based, and satellite measurements indicate large concentrations of ClO in the lower stratosphere in and near the polar vortex. The amount of local ozone depletion caused by these large ClO concentrations will depend on the relative rates of ozone loss and ClO recovery. ClO recovery occurs when NO(x), from HNO3 photolysis, reacts with ClO to form ClONO2. We show that air parcels with large amounts of ClO will experience a subsequent ozone depletion that depends on the solar zenith angle. When the solar zenith angle is large in the middle of winter, the recovery of the ClO concentration in the parcel is slow relative to ozone depletion. In the spring, when the solar zenith angle is smaller, the ClO recovery is much faster. After ClO recovery, the chlorine chemistry has not returned to normal. The ClO has been converted to ClONO2. ClO production from further encounters with PSCs will be limited by the heterogeneous reaction of ClONO2 with water. Large ozone depletions, of the type seen in the Antarctic, occur only if there is significant irreversible denitrification in the air parcel.

  8. Air parcel trajectory dispersion near the tropical tropopause

    NASA Astrophysics Data System (ADS)

    Bergman, John W.; Jensen, Eric J.; Pfister, Leonhard; Bui, Thaopaul V.

    2016-04-01

    Dispersion of backward air parcel trajectories that are initially tightly grouped near the tropical tropopause is examined using three ensemble approaches: "RANWIND," in which different ensemble members use identical resolved wind fluctuations but different realizations of stochastic, multifractal simulations of unresolved winds; "PERTLOC," in which members use identical resolved wind fields but initial locations are perturbed 2° in latitude and longitude; and a multimodel ensemble ("MULTIMODEL") that uses identical initial conditions but different resolved wind fields and/or trajectory formulations. Comparisons among the approaches distinguish, to some degree, physical dispersion from that due to data uncertainty and the impacts of unresolved wind fluctuations from those of resolved variability. Dispersion rates are robust properties of trajectories near the tropical tropopause. Horizontal dispersion rates are typically ~3°/d, which is large enough to spread parcels throughout the tropics within typical tropical tropopause layer transport times (30-60 days) and underscores the importance of averaging large collections of trajectories to obtain reliable parcel source and pathway distributions. Vertical dispersion rates away from convection are ~2-3 hPa/d. Dispersion is primarily carried out by the resolved flow, and the RANWIND approach provides a plausible representation of actual trajectory dispersion rates, while PERTLOC provides a reasonable and inexpensive alternative to RANWIND. In contrast, dispersion from the MULTIMODEL calculations is important because it reflects systematic differences in resolved wind fields from different reanalysis data sets.

  9. Uncertainty and dispersion in air parcel trajectories near the tropical tropopause

    NASA Astrophysics Data System (ADS)

    Bergman, John; Jensen, Eric; Pfister, Leonhard; Bui, Thoapaul

    2016-04-01

    The Tropical Tropopause Layer (TTL) is important as the gateway to the stratosphere for chemical constituents produced at the Earth's surface. As such, understanding the processes that transport air through the upper tropical troposphere is important for a number of current scientific issues such as the impact of stratospheric water vapor on the global radiative budget and the depletion of ozone by both anthropogenically- and naturally-produced halocarbons. Compared to the lower troposphere, transport in the TTL is relatively unaffected by turbulent motion. Consequently, Lagrangian particle models are thought to provide reasonable estimates of parcel pathways through the TTL. However, there are complications that make trajectory analyses difficult to interpret; uncertainty in the wind data used to drive these calculations and trajectory dispersion being among the most important. These issues are examined using ensembles of backward air parcel trajectories that are initially tightly grouped near the tropical tropopause using three approaches: A Monte Carlo ensemble, in which different members use identical resolved wind fluctuations but different realizations of stochastic, multi-fractal simulations of unresolved winds, perturbed initial location ensembles, in which members use identical resolved wind fields but initial locations are displaced 2° in latitude and longitude, and a multi-model ensemble that uses identical initial conditions but different resolved wind fields and/or trajectory formulations. Comparisons among the approaches distinguish, to some degree, physical dispersion from that due to data uncertainty and the impact of unresolved wind fluctuations from that of resolved variability.

  10. The Cirrus Parcel Model Comparison Project. Phase 1

    NASA Technical Reports Server (NTRS)

    Lin, Ruei-Fong; Starr, D.; DeMott, P.; Cotten, R.; Jensen, E.; Sassen, K.

    2000-01-01

    The cirrus Parcel Model Comparison Project involves the systematic comparison of current models of ice crystal nucleation and growth for specified, typical, cirrus cloud environments. In Phase 1 of the project reported here, simulated cirrus cloud microphysical properties are compared for situations of "warm" (-40 C) and "cold" (-60 C) cirrus subject to updrafts of 4, 20 and 100 centimeters per second, respectively. Five models are participating in the project. These models employ explicit microphysical schemes wherein the size distribution of each class of particles (aerosols and ice crystals) is resolved into bins. Simulations are made including both homogeneous and heterogeneous ice nucleation mechanisms. A single initial aerosol population of sulfuric acid particles is prescribed for all simulations. To isolate the treatment of the homogeneous freezing (of haze drops) nucleation process, the heterogeneous nucleation mechanism is disabled for a second parallel set of simulations. Qualitative agreement is found amongst the models for the homogeneous-nucleation-only simulations, e.g., the number density of nucleated ice crystals increases with the strength of the prescribed updraft. However, non-negligible quantitative differences are found. Systematic bias exists between results of a model based on a modified classical theory approach and models using an effective freezing temperature approach to the treatment of nucleation. Each approach is constrained by critical freezing data from laboratory studies. This information is necessary, but not sufficient, to construct consistent formulae for the two approaches. Large haze particles may deviate considerably from equilibrium size in moderate to strong updrafts (20-100 centimeters per second) at -60 C when the commonly invoked equilibrium assumption is lifted. The resulting difference in particle-size-dependent solution concentration of haze particles may significantly affect the ice nucleation rate during the initial

  11. Use of Item Parceling in Structural Equation Modeling with Missing Data

    ERIC Educational Resources Information Center

    Orcan, Fatih

    2013-01-01

    Parceling is referred to as a procedure for computing sums or average scores across multiple items. Parcels instead of individual items are then used as indicators of latent factors in the structural equation modeling analysis (Bandalos 2002, 2008; Little et al., 2002; Yang, Nay, & Hoyle, 2010). Item parceling may be applied to alleviate some…

  12. In situ observations of dehydrated air parcels advected horizontally in the Tropical Tropopause Layer of the western Pacific

    NASA Astrophysics Data System (ADS)

    Hasebe, F.; Fujiwara, M.; Nishi, N.; Shiotani, M.; Vömel, H.; Oltmans, S.; Takashima, H.; Saraspriya, S.; Komala, N.; Inai, Y.

    2007-02-01

    Water vapor observations by chilled-mirror hygrometers were conducted at Bandung, Indonesia (6.90° S, 107.60° E) and Tarawa, Kiribati (1.35° N, 172.91° E) in December 2003 to examine the efficiency of dehydration during horizontal advection in the tropical tropopause layer (TTL). Trajectory analyses based on bundles of isentropic trajectories suggest that the modification of air parcels' identity due to irreversible mixing by the branching-out and merging-in of nearby trajectories is found to be an important factor, in addition to the routes air parcels follow, for interpreting the water vapor concentrations observed by chilled-mirror frostpoint hygrometers in the TTL. Clear correspondence between the observed water vapor concentration and the estimated temperature history of air parcels is found showing that drier air parcels were exposed to lower temperatures than were more humid ones during advection. Although the number of observations is quite limited, the water content in the observed air parcels on many occasions was more than that expected from the minimum saturation mixing ratio during horizontal advection prior to sonde observations.

  13. DESCRIPTION OF ATMOSPHERIC TRANSPORT PROCESSES IN EULERIAN AIR QUALITY MODELS

    EPA Science Inventory

    Key differences among many types of air quality models are the way atmospheric advection and turbulent diffusion processes are treated. Gaussian models use analytical solutions of the advection-diffusion equations. Lagrangian models use a hypothetical air parcel concept effecti...

  14. Model-Based Analysis of Electric Drive Options for Medium-Duty Parcel Delivery Vehicles: Preprint

    SciTech Connect

    Barnitt, R. A.; Brooker, A. D.; Ramroth, L.

    2010-12-01

    Medium-duty vehicles are used in a broad array of fleet applications, including parcel delivery. These vehicles are excellent candidates for electric drive applications due to their transient-intensive duty cycles, operation in densely populated areas, and relatively high fuel consumption and emissions. The National Renewable Energy Laboratory (NREL) conducted a robust assessment of parcel delivery routes and completed a model-based techno-economic analysis of hybrid electric vehicle (HEV) and plug-in hybrid electric vehicle configurations. First, NREL characterized parcel delivery vehicle usage patterns, most notably daily distance driven and drive cycle intensity. Second, drive-cycle analysis results framed the selection of drive cycles used to test a parcel delivery HEV on a chassis dynamometer. Next, measured fuel consumption results were used to validate simulated fuel consumption values derived from a dynamic model of the parcel delivery vehicle. Finally, NREL swept a matrix of 120 component size, usage, and cost combinations to assess impacts on fuel consumption and vehicle cost. The results illustrated the dependency of component sizing on drive-cycle intensity and daily distance driven and may allow parcel delivery fleets to match the most appropriate electric drive vehicle to their fleet usage profile.

  15. Why item parcels are (almost) never appropriate: two wrongs do not make a right--camouflaging misspecification with item parcels in CFA models.

    PubMed

    Marsh, Herbert W; Lüdtke, Oliver; Nagengast, Benjamin; Morin, Alexandre J S; Von Davier, Matthias

    2013-09-01

    The present investigation has a dual focus: to evaluate problematic practice in the use of item parcels and to suggest exploratory structural equation models (ESEMs) as a viable alternative to the traditional independent clusters confirmatory factor analysis (ICM-CFA) model (with no cross-loadings, subsidiary factors, or correlated uniquenesses). Typically, it is ill-advised to (a) use item parcels when ICM-CFA models do not fit the data, and (b) retain ICM-CFA models when items cross-load on multiple factors. However, the combined use of (a) and (b) is widespread and often provides such misleadingly good fit indexes that applied researchers might believe that misspecification problems are resolved--that 2 wrongs really do make a right. Taking a pragmatist perspective, in 4 studies we demonstrate with responses to the Rosenberg Self-Esteem Inventory (Rosenberg, 1965), Big Five personality factors, and simulated data that even small cross-loadings seriously distort relations among ICM-CFA constructs or even decisions on the number of factors; although obvious in item-level analyses, this is camouflaged by the use of parcels. ESEMs provide a viable alternative to ICM-CFAs and a test for the appropriateness of parcels. The use of parcels with an ICM-CFA model is most justifiable when the fit of both ICM-CFA and ESEM models is acceptable and equally good, and when substantively important interpretations are similar. However, if the ESEM model fits the data better than the ICM-CFA model, then the use of parcels with an ICM-CFA model typically is ill-advised--particularly in studies that are also interested in scale development, latent means, and measurement invariance.

  16. Identifying functional subdivisions in the human brain using meta-analytic activation modeling-based parcellation.

    PubMed

    Yang, Yong; Fan, Lingzhong; Chu, Congying; Zhuo, Junjie; Wang, Jiaojian; Fox, Peter T; Eickhoff, Simon B; Jiang, Tianzi

    2016-01-01

    Parcellation of the human brain into fine-grained units by grouping voxels into distinct clusters has been an effective approach for delineating specific brain regions and their subregions. Published neuroimaging studies employing coordinate-based meta-analyses have shown that the activation foci and their corresponding behavioral categories may contain useful information about the anatomical-functional organization of brain regions. Inspired by these developments, we proposed a new parcellation scheme called meta-analytic activation modeling-based parcellation (MAMP) that uses meta-analytically obtained information. The raw meta data, including the experiments and the reported activation coordinates related to a brain region of interest, were acquired from the Brainmap database. Using this data, we first obtained the "modeled activation" pattern by modeling the voxel-wise activation probability given spatial uncertainty for each experiment that featured at least one focus within the region of interest. Then, we processed these "modeled activation" patterns across the experiments with a K-means clustering algorithm to group the voxels into different subregions. In order to verify the reliability of the method, we employed our method to parcellate the amygdala and the left Brodmann area 44 (BA44). The parcellation results were quite consistent with previous cytoarchitectonic and in vivo neuroimaging findings. Therefore, the MAMP proposed in the current study could be a useful complement to other methods for uncovering the functional organization of the human brain.

  17. 76 FR 77856 - International Mail Price Change for Inbound Air Parcel Post

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-12-14

    ... service bonus eligibility and submission of annual inflation information from the Consumer Price Index for... may qualify for percentage ``bonuses'' to their base rate based upon their provision of certain value... International Bureau publishes an annual notice establishing the postal administration's parcel rates for...

  18. Predictive Capabilities of a Relaxation Model for Parcel-Based Granular Flow Simulations

    NASA Astrophysics Data System (ADS)

    Radl, Stefan; Sundaresan, Sankaran

    2011-11-01

    Parcel-based methods have a great potential to reduce the computational cost of particle simulations for dense flows. Here we investigate a relaxation model, similar to that of Bhatnagar-Gross-Krook (BGK), when applied to such a parcel-based simulation method. Specifically, we have chosen the simulation methodology initially proposed by Patankar and Joseph, and combined it with the relaxation model published by O'Rourke and Snider. We show that a relaxation model is key to correctly predicting macroscopic flow features, e.g., the scattering pattern of a granular jet impinging on a flat surface, studied experimentally by Cheng et al.. Simple shear flow simulations reveal that calculation of the locally-averaged velocity is a critical ingredient to correctly predict streaming and collisional stresses. SR acknowledges the support of the Austrian Science Foundation through the Erwin-Schroedinger fellowship J-3072.

  19. Variability in Parameter Estimates and Model Fit across Repeated Allocations of Items to Parcels

    ERIC Educational Resources Information Center

    Sterba, Sonya K.; MacCallum, Robert C.

    2010-01-01

    Different random or purposive allocations of items to parcels within a single sample are thought not to alter structural parameter estimates as long as items are unidimensional and congeneric. If, additionally, numbers of items per parcel and parcels per factor are held fixed across allocations, different allocations of items to parcels within a…

  20. Improving stable isotope-based reconstructions of Sierra Nevada paleotopography using insights from regional air parcel trajectories

    NASA Astrophysics Data System (ADS)

    Lechler, A.; Galewsky, J.

    2012-12-01

    The geodynamic evolution of the Sierra Nevada Mountains of the western US remains subject to debate due to the lack of consensus on the Cenozoic paleoelevation history of the range. The majority of recent studies attempting to quantify the surface uplift history of the Sierra Nevada rely on stable isotope paleoaltimetry methods that often implicitly assume that atmospheric flow interactions with topography can be simply modeled as a Rayleigh distillation process in which air mass trajectories ascend and rainout heavy isotopologues of water (18O and D) across topographic barriers relatively unimpeded. Accordingly, stable isotope paleoaltimetry studies commonly target leeward side paleo-meteoric water proxies to constrain paleotopography of the windward barrier. We present a modern (1979 - 2010) air parcel trajectory analysis using the Hybrid Single Particle Lagrangian Integrated Trajectory (HYSPLIT) model that shows that the fundamental assumptions of stable isotope paleoaltimetry are often violated in the Sierra Nevada region. Trajectory analysis indicates that westerly air masses are frequently orographically blocked by and redirected around the higher elevations (> 2.5 km) of the Sierra Nevada. As a result, trajectories reaching the Sierran lee commonly travel around, rather than over, the highest range elevations. These blocking and redirection effects are particularly pronounced for leeward sites that are distal (> 150 km) from the Sierran crest but are also evident in trajectory patterns for both windward and proximal leeward locations in the northern Sierra Nevada. In addition, trajectory patterns indicate that much of the Sierran lee receives a non-negligible proportion of annual precipitation from summer storm systems sourced in the subtropical Pacific Ocean and Gulf of California that have little to no interaction with Sierran topography. This trajectory analysis highlights the complexity of orographic precipitation patterns and processes in the Sierra

  1. Cirrus Parcel Model Comparison Project. Phase 1; The Critical Components to Simulate Cirrus Initiation Explicitly

    NASA Technical Reports Server (NTRS)

    Lin, Ruei-Fong; Starr, David OC; DeMott, Paul J.; Cotton, Richard; Sassen, Kenneth; Jensen, Eric; Einaudi, Franco (Technical Monitor)

    2001-01-01

    clear if the two approaches can be made consistent. Large haze particles may deviate considerably from equilibrium size in moderate to strong updrafts (20-100 centimeters per second) at -60 C when the commonly invoked equilibrium assumption is lifted. The resulting difference in particle-size- dependent solution concentration of haze particles may significantly affect the ice particle formation rate during the initial nucleation interval. The uptake rate for water vapor excess by ice crystals is another key component regulating the total number of nucleated ice crystals. This rate, the product of particle number concentration and ice crystal diffusional growth rate, which is particularly sensitive to the deposition coefficient when ice particles are small, modulates the peak particle formation rate achieved in an air parcel and the duration of the active nucleation time period. The effects of heterogeneous nucleation are most pronounced in weak updraft situations. Vapor competition by the heterogeneously nucleated ice crystals may limit the achieved ice supersaturation and thus suppresses the contribution of homogeneous nucleation. Correspondingly, ice crystal number density is markedly reduced. Definitive laboratory and atmospheric benchmark data are needed for the heterogeneous nucleation process. Inter-model differences are correspondingly greater than in the case of the homogeneous nucleation process acting alone.

  2. Green infrastructure retrofits on residential parcels: Ecohydrologic modeling for stormwater design

    NASA Astrophysics Data System (ADS)

    Miles, B.; Band, L. E.

    2014-12-01

    To meet water quality goals stormwater utilities and not-for-profit watershed organizations in the U.S. are working with citizens to design and implement green infrastructure on residential land. Green infrastructure, as an alternative and complement to traditional (grey) stormwater infrastructure, has the potential to contribute to multiple ecosystem benefits including stormwater volume reduction, carbon sequestration, urban heat island mitigation, and to provide amenities to residents. However, in small (1-10-km2) medium-density urban watersheds with heterogeneous land cover it is unclear whether stormwater retrofits on residential parcels significantly contributes to reduce stormwater volume at the watershed scale. In this paper, we seek to improve understanding of how small-scale redistribution of water at the parcel scale as part of green infrastructure implementation affects urban water budgets and stormwater volume across spatial scales. As study sites we use two medium-density headwater watersheds in Baltimore, MD and Durham, NC. We develop ecohydrology modeling experiments to evaluate the effectiveness of redirecting residential rooftop runoff to un-altered pervious surfaces and to engineered rain gardens to reduce stormwater runoff. As baselines for these experiments, we performed field surveys of residential rooftop hydrologic connectivity to adjacent impervious surfaces, and found low rates of connectivity. Through simulations of pervasive adoption of downspout disconnection to un-altered pervious areas or to rain garden stormwater control measures (SCM) in these catchments, we find that most parcel-scale changes in stormwater fate are attenuated at larger spatial scales and that neither SCM alone is likely to provide significant changes in streamflow at the watershed scale.

  3. Three Approaches to Using Lengthy Ordinal Scales in Structural Equation Models: Parceling, Latent Scoring, and Shortening Scales

    ERIC Educational Resources Information Center

    Yang, Chongming; Nay, Sandra; Hoyle, Rick H.

    2010-01-01

    Lengthy scales or testlets pose certain challenges for structural equation modeling (SEM) if all the items are included as indicators of a latent construct. Three general approaches to modeling lengthy scales in SEM (parceling, latent scoring, and shortening) have been reviewed and evaluated. A hypothetical population model is simulated containing…

  4. Three Approaches to Using Lengthy Ordinal Scales in Structural Equation Models: Parceling, Latent Scoring, and Shortening Scales

    PubMed Central

    Yang, Chongming; Nay, Sandra; Hoyle, Rick H.

    2009-01-01

    Lengthy scales or testlets pose certain challenges for structural equation modeling (SEM) if all the items are included as indicators of a latent construct. Three general approaches (parceling, latent scoring, and shortening) to modeling lengthy scales in SEM were reviewed and evaluated. A hypothetical population model was simulated containing two exogenous constructs with 14 indicators each and an endogenous construct with four indicators. The simulation generated data sets with varying numbers of response options, two types of distributions, factor loadings ranging from low to high, and sample sizes ranging from small to moderate. The population model was varied to incorporate one of the following: (1) single parcels, (2) various parcels as indicators of two exogenous constructs, (3) latent scores as observed exogenous variables, and (4) four and six of individual items as indicators of two exogenous constructs. The dependent variables evaluated were biases in the covariance and partial covariance population parameters. Biases in these parameters were found to be minimal under the following conditions: (1) when parcels of indicators of five response options were used as indicators of two latent exogenous constructs; (2) when latent scores were used as observed variables at sample sizes above 100 and with indicators that were relatively less skewed in the case of dichotomous indicators; and (3) when four or six individual items with high or diverse factor loadings were used as indicators of two exogenous constructs. These findings provided guidelines for resolving the inconsistency of findings from applying various approaches to empirical data. PMID:20514149

  5. Data model for the collaboration between land administration systems and agricultural land parcel identification systems.

    PubMed

    Inan, Halil Ibrahim; Sagris, Valentina; Devos, Wim; Milenov, Pavel; van Oosterom, Peter; Zevenbergen, Jaap

    2010-12-01

    The Common Agricultural Policy (CAP) of the European Union (EU) has dramatically changed after 1992, and from then on the CAP focused on the management of direct income subsidies instead of production-based subsidies. For this focus, Member States (MS) are expected to establish Integrated Administration and Control System (IACS), including a Land Parcel Identification System (LPIS) as the spatial part of IACS. Different MS have chosen different solutions for their LPIS. Currently, some MS based their IACS/LPIS on data from their Land Administration Systems (LAS), and many others use purpose built special systems for their IACS/LPIS. The issue with these different IACS/LPIS is that they do not have standardized structures; rather, each represents a unique design in each MS, both in the case of LAS based or special systems. In this study, we aim at designing a core data model for those IACS/LPIS based on LAS. For this purpose, we make use of the ongoing standardization initiatives for LAS (Land Administration Domain Model: LADM) and IACS/LPIS (LPIS Core Model: LCM). The data model we propose in this study implies the collaboration between LADM and LCM and includes some extensions. Some basic issues with the collaboration model are discussed within this study: registration of farmers, land use rights and farming limitations, geometry/topology, temporal data management etc. For further explanation of the model structure, sample instance level diagrams illustrating some typical situations are also included.

  6. The Use of Compensated Aerological No-Lift Balloons to Determine Relatively Long-Term Dry-Air Parcel Trajectories.

    NASA Astrophysics Data System (ADS)

    Terliuc, Benjamin; Asculai, Ephraim; Doron, Eli

    1983-10-01

    A method to compensate the loss of buoyancy due to gas leakage from aerological no-lift balloons is presented. The method is implemented by means of a double vessel device that supplies a constant liquid outflow at constant temperature. It is shown that the average buoyancy loss rate dependence on temperature is almost perfectly matched by the outflow rate dependence on temperature when soya-bean oil is used. The device is simple, inexpensive and can be easily manufactured using standard laboratory equipment.A simple and safe method to carry no-lift systems to prefixed levels is also presented. It is based on a single 30 g pilot balloon provided with a gas leakage nozzle, inflated with H2 to a calibrated initial free-lift. The balloon is totally emptied at the required level, and remains suspended from the no-lift system.The whole system can be easily prepared under field conditions to be used in long travel-time studies of dry-air parcel trajectories in the atmosphere.An example of the use of the improved method over complex terrain is presented. A no-lift system provided with a 1680 MHz radiosonde transmitter, was tracked by two RD-65 radio-theodolites, to investigate the effects of the topographic structure of the Lake Kinneret (Sea of Galilee) area on the Mediterranean sea breeze summer regime. The system was tracked for at least one hour, following a trajectory with severe vertical variations. This increases our confidence in the ability to track much longer trajectories, if required.

  7. Hydraulic Hybrid and Conventional Parcel Delivery Vehicles' Measured Laboratory Fuel Economy on Targeted Drive Cycles

    SciTech Connect

    Lammert, M. P.; Burton, J.; Sindler, P.; Duran, A.

    2014-10-01

    This research project compares laboratory-measured fuel economy of a medium-duty diesel powered hydraulic hybrid vehicle drivetrain to both a conventional diesel drivetrain and a conventional gasoline drivetrain in a typical commercial parcel delivery application. Vehicles in this study included a model year 2012 Freightliner P100H hybrid compared to a 2012 conventional gasoline P100 and a 2012 conventional diesel parcel delivery van of similar specifications. Drive cycle analysis of 484 days of hybrid parcel delivery van commercial operation from multiple vehicles was used to select three standard laboratory drive cycles as well as to create a custom representative cycle. These four cycles encompass and bracket the range of real world in-use data observed in Baltimore United Parcel Service operations. The NY Composite cycle, the City Suburban Heavy Vehicle Cycle cycle, and the California Air Resources Board Heavy Heavy-Duty Diesel Truck (HHDDT) cycle as well as a custom Baltimore parcel delivery cycle were tested at the National Renewable Energy Laboratory's Renewable Fuels and Lubricants Laboratory. Fuel consumption was measured and analyzed for all three vehicles. Vehicle laboratory results are compared on the basis of fuel economy. The hydraulic hybrid parcel delivery van demonstrated 19%-52% better fuel economy than the conventional diesel parcel delivery van and 30%-56% better fuel economy than the conventional gasoline parcel delivery van on cycles other than the highway-oriented HHDDT cycle.

  8. Parcellating connectivity in spatial maps.

    PubMed

    Baldassano, Christopher; Beck, Diane M; Fei-Fei, Li

    2015-01-01

    A common goal in biological sciences is to model a complex web of connections using a small number of interacting units. We present a general approach for dividing up elements in a spatial map based on their connectivity properties, allowing for the discovery of local regions underlying large-scale connectivity matrices. Our method is specifically designed to respect spatial layout and identify locally-connected clusters, corresponding to plausible coherent units such as strings of adjacent DNA base pairs, subregions of the brain, animal communities, or geographic ecosystems. Instead of using approximate greedy clustering, our nonparametric Bayesian model infers a precise parcellation using collapsed Gibbs sampling. We utilize an infinite clustering prior that intrinsically incorporates spatial constraints, allowing the model to search directly in the space of spatially-coherent parcellations. After showing results on synthetic datasets, we apply our method to both functional and structural connectivity data from the human brain. We find that our parcellation is substantially more effective than previous approaches at summarizing the brain's connectivity structure using a small number of clusters, produces better generalization to individual subject data, and reveals functional parcels related to known retinotopic maps in visual cortex. Additionally, we demonstrate the generality of our method by applying the same model to human migration data within the United States. This analysis reveals that migration behavior is generally influenced by state borders, but also identifies regional communities which cut across state lines. Our parcellation approach has a wide range of potential applications in understanding the spatial structure of complex biological networks.

  9. The Origin of Stratospheric Air

    NASA Astrophysics Data System (ADS)

    Schoeberl, M. R.; Dessler, A. E.; Wang, T.

    2012-12-01

    The domain-filling, forward trajectory calculation model developed by Schoeberl and Dessler [2011] is used to investigate the origin of air that enters the stratosphere, and the origin of the driest and wettest air parcels. We compare results from NASA's MERRA, NCEP's CFSR, and ECMWF's ERAi reanalyses in a non-convection simulation. The stratospheric air parcel origin is related to but distinct from the location of final dehydration zones. Final dehydration zones control stratospheric water vapor, but stratospheric air origin tells about the origin of non-water soluble constituents such as HCN or CO. The models broadly agree that stratospheric air parcel origins follow the ITCZ in winter with maxima over the tropical west Pacific and South America. The origins are more broadly dispersed in summer. Somewhat surprisingly, the seasonal cycle for the origins is small with most of the air parcels entering the stratosphere from 360K originate in non-DJF months. The origin of the wettest and driest parcels shows that the driest parcels (1-3 ppmv) originate in the tropical West Pacific while the wettest (6-10 ppmv) parcels originate in the East Pacific/ Central America.

  10. AIR Model Preflight Analysis

    NASA Technical Reports Server (NTRS)

    Tai, H.; Wilson, J. W.; Maiden, D. L.

    2003-01-01

    The atmospheric ionizing radiation (AIR) ER-2 preflight analysis, one of the first attempts to obtain a relatively complete measurement set of the high-altitude radiation level environment, is described in this paper. The primary thrust is to characterize the atmospheric radiation and to define dose levels at high-altitude flight. A secondary thrust is to develop and validate dosimetric techniques and monitoring devices for protecting aircrews. With a few chosen routes, we can measure the experimental results and validate the AIR model predictions. Eventually, as more measurements are made, we gain more understanding about the hazardous radiation environment and acquire more confidence in the prediction models.

  11. Optimal combination of multiple cortical surface parcellations

    NASA Astrophysics Data System (ADS)

    Hu, Xintao; Guo, Lei; Li, Gang; Li, Kaiming; Liu, Tianming

    2010-03-01

    A variety of methodologies have been developed for the parcellation of human cortical surface into sulcal or gyral regions due to its importance in structural and functional mapping of the human brain. However, characterizing the performance of surface parcellation methods and the estimation of ground truth of segmentation are still open problems. In this paper, we present an algorithm for simultaneous truth and performance estimation of various approaches for human cortical surface parcellation. The probabilistic true segmentation is estimated as a weighted combination of the segmentations resulted from multiple methods. Afterward, an Expectation-Maximization (EM) algorithm is used to optimize the weighting depending on the estimated performance level of each method. Furthermore, a spatial homogeneity constraint modeled by the Hidden Markov Random Field (HMRF) theory is incorporated to refine the estimated true segmentation into a spatially homogenous decision. The proposed method has been evaluated using both synthetic and real data. The experimental results demonstrate the validity of the method proposed in this paper. Also, it has been used to generate reference sulci regions to perform a comparison study of three methods for cortical surface parcellation.

  12. Air modeling: Air dispersion models; regulatory applications and technological advances

    SciTech Connect

    Miller, M.; Liles, R.

    1995-09-01

    Air dispersion models are a useful and practical tool for both industry and regulatory agencies. They serve as tools for engineering, permitting, and regulations development. Their cost effectiveness and ease of implementation compared to ambient monitoring is perhaps their most-appealing trait. Based on the current momentum within the U.S. EPA to develop better models and contain regulatory burdens on industry, it is likely that air dispersion modeling will be a major player in future air regulatory initiatives.

  13. The harmonised data model for assessing Land Parcel Identification Systems compliance with requirements of direct aid and agri-environmental schemes of the CAP.

    PubMed

    Sagris, Valentina; Wojda, Piotr; Milenov, Pavel; Devos, Wim

    2013-03-30

    The EU Common Agricultural Policy (CAP) subsidies to farmers are administered through dedicated information systems, a part of which is the GIS-based Land Parcel Identification System (LPIS). The requirement to map and record land eligible for payments has led to a situation where the agricultural administrations have acquired a large amount of geographic data. As the geospatial community of data producers, custodians and users has grown during the last decades, so has the need to assess the quality and consistency of the LPIS towards the EU regulations on the CAP as well as for cross compliance with environmental legislation. In view of this, a LPIS Conceptual Model (LCM) is presented in this paper in order to address harmonisation and data quality needs. The ISO 19100 series standards on geoinformatics were used for LCM development, including an UML modelling approach and the handling of the quality of geographical information. This paper describes the core elements of the LCM and their integration with data supporting management of agri-environment schemes. Later, the paper shows how the LCM is used for conformity and quality checks of the member states' LPIS system; an Abstract Test Suite (ATS) for mapping the LCM model against existing system implementations was developed and tested in collaboration with several member states. PMID:23391811

  14. The harmonised data model for assessing Land Parcel Identification Systems compliance with requirements of direct aid and agri-environmental schemes of the CAP.

    PubMed

    Sagris, Valentina; Wojda, Piotr; Milenov, Pavel; Devos, Wim

    2013-03-30

    The EU Common Agricultural Policy (CAP) subsidies to farmers are administered through dedicated information systems, a part of which is the GIS-based Land Parcel Identification System (LPIS). The requirement to map and record land eligible for payments has led to a situation where the agricultural administrations have acquired a large amount of geographic data. As the geospatial community of data producers, custodians and users has grown during the last decades, so has the need to assess the quality and consistency of the LPIS towards the EU regulations on the CAP as well as for cross compliance with environmental legislation. In view of this, a LPIS Conceptual Model (LCM) is presented in this paper in order to address harmonisation and data quality needs. The ISO 19100 series standards on geoinformatics were used for LCM development, including an UML modelling approach and the handling of the quality of geographical information. This paper describes the core elements of the LCM and their integration with data supporting management of agri-environment schemes. Later, the paper shows how the LCM is used for conformity and quality checks of the member states' LPIS system; an Abstract Test Suite (ATS) for mapping the LCM model against existing system implementations was developed and tested in collaboration with several member states.

  15. INEEL AIR MODELING PROTOCOL ext

    SciTech Connect

    C. S. Staley; M. L. Abbott; P. D. Ritter

    2004-12-01

    Various laws stemming from the Clean Air Act of 1970 and the Clean Air Act amendments of 1990 require air emissions modeling. Modeling is used to ensure that air emissions from new projects and from modifications to existing facilities do not exceed certain standards. For radionuclides, any new airborne release must be modeled to show that downwind receptors do not receive exposures exceeding the dose limits and to determine the requirements for emissions monitoring. For criteria and toxic pollutants, emissions usually must first exceed threshold values before modeling of downwind concentrations is required. This document was prepared to provide guidance for performing environmental compliance-driven air modeling of emissions from Idaho National Engineering and Environmental Laboratory facilities. This document assumes that the user has experience in air modeling and dose and risk assessment. It is not intended to be a "cookbook," nor should all recommendations herein be construed as requirements. However, there are certain procedures that are required by law, and these are pointed out. It is also important to understand that air emissions modeling is a constantly evolving process. This document should, therefore, be reviewed periodically and revised as needed. The document is divided into two parts. Part A is the protocol for radiological assessments, and Part B is for nonradiological assessments. This document is an update of and supersedes document INEEL/INT-98-00236, Rev. 0, INEEL Air Modeling Protocol. This updated document incorporates changes in some of the rules, procedures, and air modeling codes that have occurred since the protocol was first published in 1998.

  16. Unsupervised fetal cortical surface parcellation

    NASA Astrophysics Data System (ADS)

    Dahdouh, Sonia; Limperopoulos, Catherine

    2016-03-01

    At the core of many neuro-imaging studies, atlas-based brain parcellations are used for example to study normal brain evolution across the lifespan. These atlases rely on the assumption that the same anatomical features are present on all subjects to be studied and that these features are stable enough to allow meaningful comparisons between different brain surfaces and structures These methods, however, often fail when applied to fetal MRI data, due to the lack of consistent anatomical features present across gestation. This paper presents a novel surface-based fetal cortical parcellation framework which attempts to circumvent the lack of consistent anatomical features by proposing a brain parcellation scheme that is based solely on learned geometrical features. A mesh signature incorporating both extrinsic and intrinsic geometrical features is proposed and used in a clustering scheme to define a parcellation of the fetal brain. This parcellation is then learned using a Random Forest (RF) based learning approach and then further refined in an alpha-expansion graph-cut scheme. Based on the votes obtained by the RF inference procedure, a probability map is computed and used as a data term in the graph-cut procedure. The smoothness term is defined by learning a transition matrix based on the dihedral angles of the faces. Qualitative and quantitative results on a cohort of both healthy and high-risk fetuses are presented. Both visual and quantitative assessments show good results demonstrating a reliable method for fetal brain data and the possibility of obtaining a parcellation of the fetal cortical surfaces using only geometrical features.

  17. A GIS-based shape index for land parcels

    NASA Astrophysics Data System (ADS)

    Demetriou, Demetris; Stillwell, John; See, Linda

    2013-08-01

    Shape analysis is of interest in many fields of spatial science and planning including land management in rural areas. In particular, evaluating the shape of existing land parcels is critical when implementing rural development schemes such as land consolidation. However, existing land parcel shape indices have major deficiencies: completely different shapes of parcels may have the same index value or similar parcel shapes may have different index scores. Thus, there is a clear requirement for a more accurate and reliable measurement method. This paper therefore presents a new parcel shape index (PSI) which integrates a geographical information system (GIS) with a multi-attribute decision-making (MADM) method. It involves the amalgamated outcome of six geometric measures represented by value functions involving a mathematical representation of judgements by experts that compare each geometric measure with that of an optimum parcel shape defined for land consolidation projects. The optimum shape has a PSI value of 1 while the worst shape has a value close to 0. The shape measures used in the model include length of sides, acute angles, reflex angles, boundary points, compactness and regularity. The paper uses data for two case study areas in Cyprus to demonstrate the superiority of the new PSI over three existing shape indices employed in other studies. The methodology utilized here can be implemented in other disciplines dealing with the assessment of objects that can be compared to an optimum.

  18. 78 FR 63521 - Product Change-Parcel Select & Parcel Return Service Negotiated Service Agreement

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-10-24

    ... From the Federal Register Online via the Government Publishing Office POSTAL SERVICE Product Change--Parcel Select & Parcel Return Service Negotiated Service Agreement AGENCY: Postal Service TM... Parcel Select & Parcel Return Service Contract 5 to Competitive Product List. Documents are available...

  19. The Origins of Air Parcels Uplifted in a Two Dimensional Gravity Wave in the Tropical Upper Troposphere During the NASA Stratosphere Troposphere Exchange Project (STEP)

    NASA Technical Reports Server (NTRS)

    Selkirk, Henry B.; Pfister, Leonhard; Chan, K. Roland; Kritz, Mark; Kelly, Ken

    1989-01-01

    During January and February 1987, as part of the Stratosphere-Troposphere Exchange Project, the NASA ER-2 made 11 flights from Darwin, Australia to investigate dehydration mechanisms in the vicinity of the tropical tropopause. After the monsoon onset in the second week of January, steady easterly flow of 15-25 ms (exp -1) was established in the upper troposphere and lower stratosphere over northern Australia and adjacent seas. Penetrating into this regime were elements of the monsoon convection such as overshooting convective turrets and extensive anvils including cyclone cloud shields. In cases of the latter, the resulting flow obstructions tended to produce mesoscale gravity waves. In several instances the ER- 2 meteorological and trace constituent measurements provide a detailed description of the structure of these gravity waves. Among these was STEP Flight 6, 22-23 January. It is of particular interest to STEP because of the close proximity of ice-laden and dehydrated air on the same isentropic surfaces. Convective events inject large amounts of ice into the upper troposphere and lower stratosphere which may not be completely removed by local precipitation processes. In the present instance, a gravity wave for removed from the source region appears to induce relativity rapid upward motion in the ice-laden air and subsequent dessication. Potential mechanisms for such a localized removal process are under investigation.

  20. Integrating biomass, sulphate and sea-salt aerosol responses into a microphysical chemical parcel model: implications for climate studies.

    PubMed

    Ghosh, S; Smith, M H; Rap, A

    2007-11-15

    Aerosols are known to influence significantly the radiative budget of the Earth. Although the direct effect (whereby aerosols scatter and absorb solar and thermal infrared radiation) has a large perturbing influence on the radiation budget, the indirect effect (whereby aerosols modify the microphysical and hence the radiative properties and amounts of clouds) poses a greater challenge to climate modellers. This is because aerosols undergo chemical and physical changes while in the atmosphere, notably within clouds, and are removed largely by precipitation. The way in which aerosols are processed by clouds depends on the type, abundance and the mixing state of the aerosols concerned. A parametrization with sulphate and sea-salt aerosol has been successfully integrated within the Hadley Centre general circulation model (GCM). The results of this combined parametrization indicate a significantly reduced role, compared with previous estimates, for sulphate aerosol in cloud droplet nucleation and, consequently, in indirect radiative forcing. However, in this bicomponent system, the cloud droplet number concentration, N(d) (a crucial parameter that is used in GCMs for radiative transfer calculations), is a smoothly varying function of the sulphate aerosol loading. Apart from sea-salt and sulphate aerosol particles, biomass aerosol particles are also present widely in the troposphere. We find that biomass smoke can significantly perturb the activation and growth of both sulphate and sea-salt particles. For a fixed salt loading, N(d) increases linearly with modest increases in sulphate and smoke masses, but significant nonlinearities are observed at higher non-sea-salt mass loadings. This non-intuitive N(d) variation poses a fresh challenge to climate modellers.

  1. Air-quality-model update

    SciTech Connect

    Penner, J.E.; Walton, J.J.

    1982-01-15

    The Livermore Regional Air Quality Model (LIRAQ) has been updated and improved. This report describes the changes that have been made in chemistry, species treatment, and boundary conditions. The results of smog chamber simulations that were used to verify the chemistry as well as simulations of the entire air quality model for two prototype days in the Bay Area are reported. The results for the prototype day simulations are preliminary due to the need for improvement in meteorology fields, but they show the dependence and sensitivity of high hour ozone to changes in selected boundary and initial conditions.

  2. Hybrid regional air pollution models

    SciTech Connect

    Drake, R.L.

    1980-03-01

    This discussion deals with a family of air quality models for predicting and analyzing the fine particulate loading in the atmosphere, for assessing the extent and degree of visibility impairment, and for determining the potential of pollutants for increasing the acidity of soils and water. The major horizontal scales of interest are from 400km to 2000km; and the time scales may vary from several hours, to days, weeks, and a few months or years, depending on the EPA regulations being addressed. First the role air quality models play in the general family of atmospheric simulation models is described. Then, the characteristics of a well-designed, comprehensive air quality model are discussed. Following this, the specific objectives of this workshop are outlined, and their modeling implications are summarized. There are significant modeling differences produced by the choice of the coordinate system, whether it be the fixed Eulerian system, the moving Lagrangian system, or some hybrid of the two. These three systems are briefly discussed, and a list of hybrid models that are currently in use are given. Finally, the PNL regional transport model is outlined and a number of research needs are listed.

  3. Air Conditioner Compressor Performance Model

    SciTech Connect

    Lu, Ning; Xie, YuLong; Huang, Zhenyu

    2008-09-05

    During the past three years, the Western Electricity Coordinating Council (WECC) Load Modeling Task Force (LMTF) has led the effort to develop the new modeling approach. As part of this effort, the Bonneville Power Administration (BPA), Southern California Edison (SCE), and Electric Power Research Institute (EPRI) Solutions tested 27 residential air-conditioning units to assess their response to delayed voltage recovery transients. After completing these tests, different modeling approaches were proposed, among them a performance modeling approach that proved to be one of the three favored for its simplicity and ability to recreate different SVR events satisfactorily. Funded by the California Energy Commission (CEC) under its load modeling project, researchers at Pacific Northwest National Laboratory (PNNL) led the follow-on task to analyze the motor testing data to derive the parameters needed to develop a performance models for the single-phase air-conditioning (SPAC) unit. To derive the performance model, PNNL researchers first used the motor voltage and frequency ramping test data to obtain the real (P) and reactive (Q) power versus voltage (V) and frequency (f) curves. Then, curve fitting was used to develop the P-V, Q-V, P-f, and Q-f relationships for motor running and stalling states. The resulting performance model ignores the dynamic response of the air-conditioning motor. Because the inertia of the air-conditioning motor is very small (H<0.05), the motor reaches from one steady state to another in a few cycles. So, the performance model is a fair representation of the motor behaviors in both running and stalling states.

  4. Automatic parcellation of longitudinal cortical surfaces

    NASA Astrophysics Data System (ADS)

    Alassaf, Manal H.; Hahn, James K.

    2015-03-01

    We present a novel automatic method to parcellate the cortical surfaces of the neonatal brain longitudinal atlas at different stages of development. A labeled brain atlas of newborn at 41 weeks gestational age (GA) is used to propagate labels of anatomical regions of interest to an unlabeled spatio-temporal atlas, which provides a dynamic model of brain development at each week between 28-44 GA weeks. First, labels from the cortical volume of the labeled newborn brain are propagated to an age-matched cortical surface from the spatio-temporal atlas. Then, labels are propagated across the cortical surfaces of each week of the spatio-temporal atlas by registering successive cortical surfaces using a novel approach and an energy optimization function. This procedure incorporates local and global, spatial and temporal information when assigning the labels to each surface. The result is a complete parcellation of 17 neonatal brain surfaces of the spatio-temporal atlas with similar points per labels distributions across weeks.

  5. Uncertainty in Air Quality Modeling.

    NASA Astrophysics Data System (ADS)

    Fox, Douglas G.

    1984-01-01

    Under the direction of the AMS Steering Committee for the EPA Cooperative Agreement on Air Quality Modeling, a small group of scientists convened to consider the question of uncertainty in air quality modeling. Because the group was particularly concerned with the regulatory use of models, its discussion focused on modeling tall stack, point source emissions.The group agreed that air quality model results should be viewed as containing both reducible error and inherent uncertainty. Reducible error results from improper or inadequate meteorological and air quality data inputs, and from inadequacies in the models. Inherent uncertainty results from the basic stochastic nature of the turbulent atmospheric motions that are responsible for transport and diffusion of released materials. Modelers should acknowledge that all their predictions to date contain some associated uncertainty and strive also to quantify uncertainty.How can the uncertainty be quantified? There was no consensus from the group as to precisely how uncertainty should be calculated. One subgroup, which addressed statistical procedures, suggested that uncertainty information could be obtained from comparisons of observations and predictions. Following recommendations from a previous AMS workshop on performance evaluation (Fox. 1981), the subgroup suggested construction of probability distribution functions from the differences between observations and predictions. Further, they recommended that relatively new computer-intensive statistical procedures be considered to improve the quality of uncertainty estimates for the extreme value statistics of interest in regulatory applications.A second subgroup, which addressed the basic nature of uncertainty in a stochastic system, also recommended that uncertainty be quantified by consideration of the differences between observations and predictions. They suggested that the average of the difference squared was appropriate to isolate the inherent uncertainty that

  6. 77 FR 28409 - Product Change-Parcel Select & Parcel Return Service Negotiated Service Agreement

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-05-14

    ... From the Federal Register Online via the Government Publishing Office POSTAL SERVICE Product Change--Parcel Select & Parcel Return Service Negotiated Service Agreement AGENCY: Postal Service\\TM... Postal Regulatory Commission a Request of the United States Postal Service to Add Parcel Select &...

  7. 77 FR 37078 - Product Change-Parcel Select and Parcel Return Service Negotiated Service Agreement

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-06-20

    ... From the Federal Register Online via the Government Publishing Office POSTAL SERVICE Product Change--Parcel Select and Parcel Return Service Negotiated Service Agreement AGENCY: Postal Service TM... Postal Regulatory Commission a Request of the United States Postal Service to Add Parcel Select &...

  8. Air pollution modeling and its application III

    SciTech Connect

    De Wispelaere, C.

    1984-01-01

    This book focuses on the Lagrangian modeling of air pollution. Modeling cooling tower and power plant plumes, modeling the dispersion of heavy gases, remote sensing as a tool for air pollution modeling, dispersion modeling including photochemistry, and the evaluation of model performances in practical applications are discussed. Specific topics considered include dispersion in the convective boundary layer, the application of personal computers to Lagrangian modeling, the dynamic interaction of cooling tower and stack plumes, the diffusion of heavy gases, correlation spectrometry as a tool for mesoscale air pollution modeling, Doppler acoustic sounding, tetroon flights, photochemical air quality simulation modeling, acid deposition of photochemical oxidation products, atmospheric diffusion modeling, applications of an integral plume rise model, and the estimation of diffuse hydrocarbon leakages from petrochemical factories. This volume constitutes the proceedings of the Thirteenth International Technical Meeting on Air Pollution Modeling and Its Application held in France in 1982.

  9. Accounting for Parcel-Allocation Variability in Practice: Combining Sources of Uncertainty and Choosing the Number of Allocations.

    PubMed

    Sterba, Sonya K; Rights, Jason D

    2016-01-01

    Item parceling remains widely used under conditions that can lead to parcel-allocation variability in results. Hence, researchers may be interested in quantifying and accounting for parcel-allocation variability within sample. To do so in practice, three key issues need to be addressed. First, how can we combine sources of uncertainty arising from sampling variability and parcel-allocation variability when drawing inferences about parameters in structural equation models? Second, on what basis can we choose the number of repeated item-to-parcel allocations within sample? Third, how can we diagnose and report proportions of total variability per estimate arising due to parcel-allocation variability versus sampling variability? This article addresses these three methodological issues. Developments are illustrated using simulated and empirical examples, and software for implementing them is provided.

  10. 76 FR 16460 - Parcel Select Price and Classification Changes

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-03-23

    ... Parcel Select Price and Classification Changes AGENCY: Postal Regulatory Commission. ACTION: Notice... changes affecting Parcel Select. The Postal Service seeks to implement new prices for Parcel Select for... implement new prices for Parcel Select for forwarding and return to sender. The fee would be the...

  11. Proposed sale of Parcel A2 of the Oak Ridge Reservation to the City of Oak Ridge, Tennessee

    SciTech Connect

    Not Available

    1992-09-01

    Parcel A encompasses two tracts of land owned by the US Department of Energy (DOE) on the Oak Ridge Reservation (ORR). The disposal of land was recommended by a General Services Administration 1981 land utilization survey. On June 21, 1988, 21.3 ha (52.7 acres) of land, Parcel A1, were transferred to the City of Oak Ridge. Parcel Al has since been transferred to the private sector for residential development. The City of Oak Ridge has requested acquisition of Parcel A2 for residential and industrial development. The purpose of the proposed action is to transfer Parcel A2 to the City of Oak Ridge for residential and industrial development. The need for the proposed action is for DOE to respond to the General Services Administration directive to dispose of Parcel A2 and to respond to the request by the City of Oak Ridge for its acquisition and development. The proposed sale of Parcel A2 would have no environmental impacts; however, the subsequent development by the City would affect the existing environment. It is the potential effects of the City's development of Parcel A2 that are addressed by this environmental assessment (EA). Areas of concern include land use, air quality, hydrology and water quality, wetlands and floodplains, ecological resources, and socioeconomic resources.

  12. Proposed sale of Parcel A2 of the Oak Ridge Reservation to the City of Oak Ridge, Tennessee. Environmental asssessment

    SciTech Connect

    Not Available

    1992-09-01

    Parcel A encompasses two tracts of land owned by the US Department of Energy (DOE) on the Oak Ridge Reservation (ORR). The disposal of land was recommended by a General Services Administration 1981 land utilization survey. On June 21, 1988, 21.3 ha (52.7 acres) of land, Parcel A1, were transferred to the City of Oak Ridge. Parcel Al has since been transferred to the private sector for residential development. The City of Oak Ridge has requested acquisition of Parcel A2 for residential and industrial development. The purpose of the proposed action is to transfer Parcel A2 to the City of Oak Ridge for residential and industrial development. The need for the proposed action is for DOE to respond to the General Services Administration directive to dispose of Parcel A2 and to respond to the request by the City of Oak Ridge for its acquisition and development. The proposed sale of Parcel A2 would have no environmental impacts; however, the subsequent development by the City would affect the existing environment. It is the potential effects of the City`s development of Parcel A2 that are addressed by this environmental assessment (EA). Areas of concern include land use, air quality, hydrology and water quality, wetlands and floodplains, ecological resources, and socioeconomic resources.

  13. MarsAtlas: A cortical parcellation atlas for functional mapping.

    PubMed

    Auzias, Guillaume; Coulon, Olivier; Brovelli, Andrea

    2016-04-01

    An open question in neuroimaging is how to develop anatomical brain atlases for the analysis of functional data. Here, we present a cortical parcellation model based on macroanatomical information and test its validity on visuomotor-related cortical functional networks. The parcellation model is based on a recently developed cortical parameterization method (Auzias et al., [2013]: IEEE Trans Med Imaging 32:873-887), called HIP-HOP. This method exploits a set of primary and secondary sulci to create an orthogonal coordinate system on the cortical surface. A natural parcellation scheme arises from the axes of the HIP-HOP model running along the fundus of selected sulci. The resulting parcellation scheme, called MarsAtlas, complies with dorsoventral/rostrocaudal direction fields and allows inter-subject matching. To test it for functional mapping, we analyzed a MEG dataset collected from human participants performing an arbitrary visuomotor mapping task. Single-trial high-gamma activity, HGA (60-120 Hz), was estimated using spectral analysis and beamforming techniques at cortical areas arising from a Talairach atlas (i.e., Brodmann areas) and MarsAtlas. Using both atlases, we confirmed that visuomotor associations involve an increase in HGA over the sensorimotor and fronto-parietal network, in addition to medial prefrontal areas. However, MarsAtlas provided: (1) crucial functional information along both the dorsolateral and rostrocaudal direction; (2) an increase in statistical significance. To conclude, our results suggest that the MarsAtlas is a valid anatomical atlas for functional mapping, and represents a potential anatomical framework for integration of functional data arising from multiple techniques such as MEG, intracranial EEG and fMRI. PMID:26813563

  14. Physical modeling of air flow during air sparging remediation.

    PubMed

    Hu, Liming; Wu, Xiaofeng; Liu, Yan; Meegoda, Jay N; Gao, Shengyan

    2010-05-15

    Air sparging (AS) is one of the most efficient techniques for remediating saturated soils and groundwater contaminated with volatile organic compounds. A series of physical modeling tests for different sizes of porous media under varied injection pressure were conducted to investigate the effect of particle size and air injection pressure on size and shape of the zone of influence (ZOI). The test results show that ZOI can be expressed by two components: the horizontal expansion due to pneumatic fracture or preferential intrusion around the injection point and the angle of ZOI which is the angle between the vertical line and the boundary of ZOI. There exists a limited angle of ZOI for each type of porous media. The measured minimum and maximum air injection pressures in 1g tests are compared with corresponding theoretical values, and it is found that the measured minimum injection pressure is slightly lower than the theoretical value, while the measured maximum injection pressure is much higher than the theoretical maximum injection pressure. Centrifugal test results confirmed nonapplicability of theoretical maximum injection pressure to air sparging design. All of the above provide valuable information for design and theoretical modeling of air sparging for groundwater remediation.

  15. Simulation model air-to-air plate heat exchanger

    SciTech Connect

    Wetter, Michael

    1999-01-01

    A simple simulation model of an air-to-air plate heat exchanger is presented. The model belongs to a collection of simulation models that allows the eflcient computer simulation of heating, ventilation, and air-conditioning (HVAC) systems. The main emphasis of the models is to shorten computation time and to use only input data that are known in the design process of an HVAC system. The target of the models is to describe the behavior of HVAC components in the part-load operation mode, which is becoming increasingly important in energy eficient HVAC systems. The models are intended to be used for yearly energy calculations or load calculations with time steps of about 10 minutes or larger. Short- time dynamic effects, which are of interest for different aspects of control theory, are neglected. The part-load behavior is expressed in terms of the nominal condition and the dimensionless variation of the heat transfer with change of mass flow and temperature. The effectiveness- NTU relations are used to parametrize the convective heat transfer at nominal conditions and to compute the part-load condition. If the heat transfer coefficients on the two exchanger sides are not equal (i. e. due to partial bypassing of air), their ratio can be easily calculated and set as a parameter. The model is static and uses explicit equations only. The explicit model formulation ensures short computation time and numerical stability, which allows using the model with sophisticated engineering methods like automatic system optimization. This paper fully outlines the algorithm description and its simplifications. It is not tailored for any particular simulation program to ensure easy implementation in any simulation program.

  16. FORMAL UNCERTAINTY ANALYSIS OF A LAGRANGIAN PHOTOCHEMICAL AIR POLLUTION MODEL. (R824792)

    EPA Science Inventory

    This study applied Monte Carlo analysis with Latin
    hypercube sampling to evaluate the effects of uncertainty
    in air parcel trajectory paths, emissions, rate constants,
    deposition affinities, mixing heights, and atmospheric stability
    on predictions from a vertically...

  17. The Brain Atlas Concordance Problem: Quantitative Comparison of Anatomical Parcellations

    PubMed Central

    Bohland, Jason W.; Bokil, Hemant; Allen, Cara B.; Mitra, Partha P.

    2009-01-01

    Many neuroscientific reports reference discrete macro-anatomical regions of the brain which were delineated according to a brain atlas or parcellation protocol. Currently, however, no widely accepted standards exist for partitioning the cortex and subcortical structures, or for assigning labels to the resulting regions, and many procedures are being actively used. Previous attempts to reconcile neuroanatomical nomenclatures have been largely qualitative, focusing on the development of thesauri or simple semantic mappings between terms. Here we take a fundamentally different approach, discounting the names of regions and instead comparing their definitions as spatial entities in an effort to provide more precise quantitative mappings between anatomical entities as defined by different atlases. We develop an analytical framework for studying this brain atlas concordance problem, and apply these methods in a comparison of eight diverse labeling methods used by the neuroimaging community. These analyses result in conditional probabilities that enable mapping between regions across atlases, which also form the input to graph-based methods for extracting higher-order relationships between sets of regions and to procedures for assessing the global similarity between different parcellations of the same brain. At a global scale, the overall results demonstrate a considerable lack of concordance between available parcellation schemes, falling within chance levels for some atlas pairs. At a finer level, this study reveals spatial relationships between sets of defined regions that are not obviously apparent; these are of high potential interest to researchers faced with the challenge of comparing results that were based on these different anatomical models, particularly when coordinate-based data are not available. The complexity of the spatial overlap patterns revealed points to problems for attempts to reconcile anatomical parcellations and nomenclatures using strictly

  18. COMMUNITY SCALE AIR TOXICS MODELING WITH CMAQ

    EPA Science Inventory

    Consideration and movement for an urban air toxics control strategy is toward a community, exposure and risk-based modeling approach, with emphasis on assessments of areas that experience high air toxic concentration levels, the so-called "hot spots". This strategy will requir...

  19. NASA/Air Force Cost Model: NAFCOM

    NASA Technical Reports Server (NTRS)

    Winn, Sharon D.; Hamcher, John W. (Technical Monitor)

    2002-01-01

    The NASA/Air Force Cost Model (NAFCOM) is a parametric estimating tool for space hardware. It is based on historical NASA and Air Force space projects and is primarily used in the very early phases of a development project. NAFCOM can be used at the subsystem or component levels.

  20. Air Tightness of US Homes: Model Development

    SciTech Connect

    Sherman, Max H.

    2006-05-01

    Air tightness is an important property of building envelopes. It is a key factor in determining infiltration and related wall-performance properties such as indoor air quality, maintainability and moisture balance. Air leakage in U.S. houses consumes roughly 1/3 of the HVAC energy but provides most of the ventilation used to control IAQ. The Lawrence Berkeley National Laboratory has been gathering residential air leakage data from many sources and now has a database of more than 100,000 raw measurements. This paper uses that database to develop a model for estimating air leakage as a function of climate, building age, floor area, building height, floor type, energy-efficiency and low-income designations. The model developed can be used to estimate the leakage distribution of populations of houses.

  1. Census parcels cropping system classification from multitemporal remote imagery: a proposed universal methodology.

    PubMed

    García-Torres, Luis; Caballero-Novella, Juan J; Gómez-Candón, David; Peña, José Manuel

    2015-01-01

    A procedure named CROPCLASS was developed to semi-automate census parcel crop assessment in any agricultural area using multitemporal remote images. For each area, CROPCLASS consists of a) a definition of census parcels through vector files in all of the images; b) the extraction of spectral bands (SB) and key vegetation index (VI) average values for each parcel and image; c) the conformation of a matrix data (MD) of the extracted information; d) the classification of MD decision trees (DT) and Structured Query Language (SQL) crop predictive model definition also based on preliminary land-use ground-truth work in a reduced number of parcels; and e) the implementation of predictive models to classify unidentified parcels land uses. The software named CROPCLASS-2.0 was developed to semi-automatically perform the described procedure in an economically feasible manner. The CROPCLASS methodology was validated using seven GeoEye-1 satellite images that were taken over the LaVentilla area (Southern Spain) from April to October 2010 at 3- to 4-week intervals. The studied region was visited every 3 weeks, identifying 12 crops and others land uses in 311 parcels. The DT training models for each cropping system were assessed at a 95% to 100% overall accuracy (OA) for each crop within its corresponding cropping systems. The DT training models that were used to directly identify the individual crops were assessed with 80.7% OA, with a user accuracy of approximately 80% or higher for most crops. Generally, the DT model accuracy was similar using the seven images that were taken at approximately one-month intervals or a set of three images that were taken during early spring, summer and autumn, or set of two images that were taken at about 2 to 3 months interval. The classification of the unidentified parcels for the individual crops was achieved with an OA of 79.5%. PMID:25689830

  2. Census Parcels Cropping System Classification from Multitemporal Remote Imagery: A Proposed Universal Methodology

    PubMed Central

    García-Torres, Luis; Caballero-Novella, Juan J.; Gómez-Candón, David; Peña, José Manuel

    2015-01-01

    A procedure named CROPCLASS was developed to semi-automate census parcel crop assessment in any agricultural area using multitemporal remote images. For each area, CROPCLASS consists of a) a definition of census parcels through vector files in all of the images; b) the extraction of spectral bands (SB) and key vegetation index (VI) average values for each parcel and image; c) the conformation of a matrix data (MD) of the extracted information; d) the classification of MD decision trees (DT) and Structured Query Language (SQL) crop predictive model definition also based on preliminary land-use ground-truth work in a reduced number of parcels; and e) the implementation of predictive models to classify unidentified parcels land uses. The software named CROPCLASS-2.0 was developed to semi-automatically perform the described procedure in an economically feasible manner. The CROPCLASS methodology was validated using seven GeoEye-1 satellite images that were taken over the LaVentilla area (Southern Spain) from April to October 2010 at 3- to 4-week intervals. The studied region was visited every 3 weeks, identifying 12 crops and others land uses in 311 parcels. The DT training models for each cropping system were assessed at a 95% to 100% overall accuracy (OA) for each crop within its corresponding cropping systems. The DT training models that were used to directly identify the individual crops were assessed with 80.7% OA, with a user accuracy of approximately 80% or higher for most crops. Generally, the DT model accuracy was similar using the seven images that were taken at approximately one-month intervals or a set of three images that were taken during early spring, summer and autumn, or set of two images that were taken at about 2 to 3 months interval. The classification of the unidentified parcels for the individual crops was achieved with an OA of 79.5%. PMID:25689830

  3. INDOOR AIR QUALITY MODELING (CHAPTER 58)

    EPA Science Inventory

    The chapter discussses indoor air quality (IAQ) modeling. Such modeling provides a way to investigate many IAQ problems without the expense of large field experiments. Where experiments are planned, IAQ models can be used to help design experiments by providing information on exp...

  4. 7 CFR 318.13-15 - Parcel post inspection.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... 7 Agriculture 5 2014-01-01 2014-01-01 false Parcel post inspection. 318.13-15 Section 318.13-15... From Hawaii and the Territories § 318.13-15 Parcel post inspection. Inspectors are authorized to inspect, with the cooperation of the U.S. Postal Service, parcel post packages placed in the mails...

  5. Modeling upper tropospheric and lower stratospheric water vapor anomalies

    NASA Astrophysics Data System (ADS)

    Schoeberl, M. R.; Dessler, A. E.; Wang, T.

    2013-04-01

    The domain-filling, forward trajectory calculation model developed by Schoeberl and Dessler (2011) is used to further investigate processes that produce upper tropospheric and lower stratospheric water vapor anomalies. We examine the pathways parcels take from the base of the tropical tropopause layer (TTL) to the lower stratosphere. Most parcels found in the lower stratosphere arise from East Asia, the Tropical West Pacific (TWP) and the Central/South America. The belt of TTL parcel origins is very wide compared to the final dehydration zones near the top of the TTL. This is due to the convergence of rising air as a result of the stronger diabatic heating near the tropopause relative to levels above and below. The observed water vapor anomalies - both wet and dry - correspond to regions where parcels have minimal displacement from their initialization. These minimum displacement regions include the winter TWP and the Asian and American monsoons. To better understand the stratospheric water vapor concentration we introduce the water vapor spectrum and investigate the source of the wettest and driest components of the spectrum. We find that the driest air parcels that originate below the TWP, moving upward to dehydrate in the TWP cold upper troposphere. The wettest air parcels originate at the edges of the TWP as well as the summer American and Asian monsoons. The wet air parcels are important since they skew the mean stratospheric water vapor distribution toward higher values. Both TWP cold temperatures that produce dry parcels as well as extra-TWP processes that control the wet parcels determine stratospheric water vapor.

  6. Modeling upper tropospheric and lower stratospheric water vapor anomalies

    NASA Astrophysics Data System (ADS)

    Schoeberl, M. R.; Dessler, A. E.; Wang, T.

    2013-08-01

    The domain-filling, forward trajectory calculation model developed by Schoeberl and Dessler (2011) is used to further investigate processes that produce upper tropospheric and lower stratospheric water vapor anomalies. We examine the pathways parcels take from the base of the tropical tropopause layer (TTL) to the lower stratosphere. Most parcels found in the lower stratosphere arise from East Asia, the Tropical West Pacific (TWP) and Central/South America. The belt of TTL parcel origins is very wide compared to the final dehydration zones near the top of the TTL. This is due to the convergence of rising air due to the stronger diabatic heating near the tropopause relative to levels above and below. The observed water vapor anomalies - both wet and dry - correspond to regions where parcels have minimal displacement from their initialization. These minimum displacement regions include the winter TWP and the Asian and American monsoons. To better understand the stratospheric water vapor concentration we introduce the water vapor spectrum and investigate the source of the wettest and driest components of the spectrum. We find that the driest air parcels originate below the TWP, moving upward to dehydrate in the TWP cold upper troposphere. The wettest air parcels originate at the edges of the TWP as well as in the summer American and Asian monsoons. The wet air parcels are important since they skew the mean stratospheric water vapor distribution toward higher values. Both TWP cold temperatures that produce dry parcels as well as extra-TWP processes that control the wet parcels determine stratospheric water vapor.

  7. Modeling monthly mean air temperature for Brazil

    NASA Astrophysics Data System (ADS)

    Alvares, Clayton Alcarde; Stape, José Luiz; Sentelhas, Paulo Cesar; de Moraes Gonçalves, José Leonardo

    2013-08-01

    Air temperature is one of the main weather variables influencing agriculture around the world. Its availability, however, is a concern, mainly in Brazil where the weather stations are more concentrated on the coastal regions of the country. Therefore, the present study had as an objective to develop models for estimating monthly and annual mean air temperature for the Brazilian territory using multiple regression and geographic information system techniques. Temperature data from 2,400 stations distributed across the Brazilian territory were used, 1,800 to develop the equations and 600 for validating them, as well as their geographical coordinates and altitude as independent variables for the models. A total of 39 models were developed, relating the dependent variables maximum, mean, and minimum air temperatures (monthly and annual) to the independent variables latitude, longitude, altitude, and their combinations. All regression models were statistically significant ( α ≤ 0.01). The monthly and annual temperature models presented determination coefficients between 0.54 and 0.96. We obtained an overall spatial correlation higher than 0.9 between the models proposed and the 16 major models already published for some Brazilian regions, considering a total of 3.67 × 108 pixels evaluated. Our national temperature models are recommended to predict air temperature in all Brazilian territories.

  8. Subject-specific functional parcellation via Prior Based Eigenanatomy

    PubMed Central

    Dhillon, Paramveer S.; Wolk, David A.; Das, Sandhitsu R.; Ungar, Lyle H.; Gee, James C.; Avants, Brian B.

    2015-01-01

    We present a new framework for prior-constrained sparse decomposition of matrices derived from the neuroimaging data and apply this method to functional network analysis of a clinically relevant population. Matrix decomposition methods are powerful dimensionality reduction tools that have found widespread use in neuroimaging. However, the unconstrained nature of these totally data-driven techniques makes it difficult to interpret the results in a domain where network-specific hypotheses may exist. We propose a novel approach, Prior Based Eigenanatomy (p-Eigen), which seeks to identify a data-driven matrix decomposition but at the same time constrains the individual components by spatial anatomical priors (probabilistic ROIs). We formulate our novel solution in terms of prior-constrained ℓ1 penalized (sparse) principal component analysis. p-Eigen starts with a common functional parcellation for all the subjects and refines it with subject-specific information. This enables modeling of the inter-subject variability in the functional parcel boundaries and allows us to construct subject specific networks with reduced sensitivity to ROI placement. We show that while still maintaining correspondence across subjects, p-Eigen extracts biologically-relevant and patient-specific functional parcels that facilitate hypothesis-driven network analysis. We construct Default Mode Network (DMN) connectivity graphs using p-Eigen refined ROIs and use them in a classification paradigm. Our results show that the functional connectivity graphs derived from p-Eigen significantly aid classification of Mild Cognitive Impairment (MCI) as well as the prediction of scores in a Delayed Recall memory task when compared to graph metrics derived from 1) standard registration-based seed ROI definitions, 2) totally data driven ROIs 3) a model based on standard demographics plus hippocampal volume as covariates and 4) Ward Clustering based data driven ROIs. In summary, p-Eigen incarnates a new

  9. Uncertainty in Regional Air Quality Modeling

    NASA Astrophysics Data System (ADS)

    Digar, Antara

    Effective pollution mitigation is the key to successful air quality management. Although states invest millions of dollars to predict future air quality, the regulatory modeling and analysis process to inform pollution control strategy remains uncertain. Traditionally deterministic ‘bright-line’ tests are applied to evaluate the sufficiency of a control strategy to attain an air quality standard. A critical part of regulatory attainment demonstration is the prediction of future pollutant levels using photochemical air quality models. However, because models are uncertain, they yield a false sense of precision that pollutant response to emission controls is perfectly known and may eventually mislead the selection of control policies. These uncertainties in turn affect the health impact assessment of air pollution control strategies. This thesis explores beyond the conventional practice of deterministic attainment demonstration and presents novel approaches to yield probabilistic representations of pollutant response to emission controls by accounting for uncertainties in regional air quality planning. Computationally-efficient methods are developed and validated to characterize uncertainty in the prediction of secondary pollutant (ozone and particulate matter) sensitivities to precursor emissions in the presence of uncertainties in model assumptions and input parameters. We also introduce impact factors that enable identification of model inputs and scenarios that strongly influence pollutant concentrations and sensitivity to precursor emissions. We demonstrate how these probabilistic approaches could be applied to determine the likelihood that any control measure will yield regulatory attainment, or could be extended to evaluate probabilistic health benefits of emission controls, considering uncertainties in both air quality models and epidemiological concentration-response relationships. Finally, ground-level observations for pollutant (ozone) and precursor

  10. Simulation and modeling for military air operations

    NASA Astrophysics Data System (ADS)

    Kreichauf, Ruth D.; Bedros, Saad; Ateskan, Yusuf; Hespanha, Joao; Kizilocak, Hakan

    2001-09-01

    The Joint Forces Air Component Commander (JFACC) in military air operations controls the allocation of resources (wings, squadrons, air defense systems, AWACS) to different geographical locations in the theater of operations. The JFACC mission is to define a sequence of tasks for the aerospace systems at each location, and providing feedback control for the execution of these tasks in the presence of uncertainties and a hostile enemy. Honeywell Labs has been developing an innovative method for control of military air operations. The novel model predictive control (MPC) method extends the models and optimization algorithms utilized in traditional model predictive control systems. The enhancements include a tasking controller and, in a joint effort with USC, a probabilistic threat/survival map indicating high threat regions for aircraft and suggesting optimal routes to avoid these regions. A simulation/modeling environment using object-oriented methodologies has been developed to serve as an aide to demonstrate the value of MPC and facilitate its development. The simulation/modeling environment is based on an open architecture that enables the integration, evaluation, and implementation of different control approaches. The simulation offers a graphical user interface displaying the battlefield, the control performance, and a probability map displaying high threat regions. This paper describes the features of the different control approaches and their integration into the simulation environment.

  11. Moving from pixels to parcels: Modeling agricultural scenarios in the northern Great Plains using a hybrid raster- and vector-based approach

    NASA Astrophysics Data System (ADS)

    Sohl, T.; Wika, S.; Dornbierer, J.; Sayler, K. L.; Quenzer, R.

    2015-12-01

    Policy and economic driving forces have resulted in a higher demand for biofuel feedstocks in recent years, resulting in substantial increases in cultivated cropland in the northern Great Plains. A cellulosic-based biofuel industry could potentially further impact the region, with grassland and marginal agricultural land converted to perennial grasses or other feedstocks. Scenarios of projected land-use change are needed to enable regional stakeholders to plan for the potential consequences of expanded agricultural activity. Land-use models used to produce spatially explicit scenarios are typically raster-based and are poor at representing ownership units on which land-use change is based. This work describes a hybrid raster/vector-based modeling approach for modeling scenarios of agricultural change in the northern Great Plains. Regional scenarios of agricultural change from 2012 to 2050 were constructed, based partly on the U.S. Department of Energy's Billion Ton Update. Land-use data built from the 2012 Cropland Data Layer and the 2011 National Land Cover Database was used to establish initial conditions. Field boundaries from the U.S. Department of Agriculture's Common Land Unit dataset were used to establish ownership units. A modified version of the U.S. Geological Survey's Forecasting Scenarios of land-use (FORE-SCE) model was used to ingest vector-based field boundaries to facilitate the modeling of a farmer's choice of land use for a given year, while patch-based raster methodologies were used to represent expansion of urban/developed lands and other land use conversions. All modeled data were merged to a common raster dataset representing annual land use from 2012 to 2050. The hybrid modeling approach enabled the use of traditional, raster-based methods while integrating vector-based data to represent agricultural fields and other ownership-based units upon which land-use decisions are typically made.

  12. The cold air drainage model KLAM_21

    NASA Astrophysics Data System (ADS)

    Kossmann, M.

    2010-09-01

    A brief description of the physics and numerical techniques of the cold air drainage model KLAM_21 is presented. The model has been developed by the Deutscher Wetterdienst (Sievers, 2005) for simulations of nocturnal airflow in hilly and mountainous terrain under dry fair weather conditions. The model has been widely used as an environmental consultancy tool. Typical model applications include frost protection (cold air ponding) and air quality (nocturnal ventilation). The single-layer model calculates the depth and the mean wind of a surface based stable layer that evolves from a neutrally stratified atmosphere during nighttime. The prediction of the velocity and direction of the cold air drainage is based on vertically averaged momentum tendency equations. Temporal changes in the total heat deficit in the cold air layer are calculated from a prescribed local heat loss rate (describing turbulent and radiative cooling) and advection (donor-cell algorithm). The depth of the cold air layer (depth of the surface based temperature inversion) is calculated diagnostically from the total heat loss deficit. The model is initialised with neutral stratification at sunset (onset time of nocturnal cooling). Optionally, effects of an ambient (regional) wind and/or the dispersion of a passive tracer can be simulated. Integration over time is carried out on a regular Arakawa C grid using dynamically calculated time steps. Spatial gradients are discretised using centred differential quotients. The standard size of the computational domains can reach up to 1500 x 1500 grid cells. Grid resolutions usually range between 10 m and 500 m. High resolution simulation can be limited to a nested inner grid domain, while the courser outer domain is covering the entire airshed of interest. A friendly user interface allows easy setup, control, and evaluation of model simulations. Some selected examples of KLAM_21 applications are shown to illustrate the features and capabilities of the model

  13. Air freight demand models: An overview

    NASA Technical Reports Server (NTRS)

    Dajani, J. S.; Bernstein, G. W.

    1978-01-01

    A survey is presented of some of the approaches which have been considered in freight demand estimation. The few existing continuous time computer simulations of aviation systems are reviewed, with a view toward the assessment of this approach as a tool for structuring air freight studies and for relating the different components of the air freight system. The variety of available data types and sources, without which the calibration, validation and the testing of both modal split and simulation models would be impossible are also reviewed.

  14. AIR QUALITY MODELING OF AMMONIA: A REGIONAL MODELING PERSPECTIVE

    EPA Science Inventory

    The talk will address the status of modeling of ammonia from a regional modeling perspective, yet the observations and comments should have general applicability. The air quality modeling system components that are central to modeling ammonia will be noted and a perspective on ...

  15. A Lagrangian Physical-Biological Model to Study Water Parcels Associated with Algal Blooms from Southern California Bight to Todos Santos Bay.

    NASA Astrophysics Data System (ADS)

    Vivas Téllez, I. E.; Rivas, D.

    2015-12-01

    Lagrangian ocean circulation and biological dynamics are numerically studied in Todos Santos Bay during the spring of 2007. This period is particularly interesting after an intense toxic algal bloom occurred in April 2007 in this area, which was associated with the wind-driven upwelling in the region. High resolution, numerical model simulations were carried out to study dynamical features along of the Southern California Bight (SCB), the coast of the northern Baja California (BC), and the interior of Todos Santos Bay (TSB). These simulations are used in a three-dimensional Lagrangian (particle tracking) analysis which provides information about the origin and distribution of the waters present in the Bay during the occurrence of the toxic bloom. After the selection of trajectories of particles showing coherent patterns, a Nitrate-Phytoplankton-Zooplankton-Detritus (NPZD) lower trophic model is implemented to study the influence of the environmental conditions that occur during the particle advection, solving the NPZD equations at every time-varying position of the advected particles. The model is also modified for phytoplankton growth as a function of the environmental temperature to somehow emulate the life cycle of Pseudo-nitzschia. The analysis of the trajectories shows that particles mainly come from two regions: from the north, in the southern portion of SCB and from regions west of the TSB. Knowing the regional circulation patterns and their phytoplankton dynamics can help to understand and even predict the origin and destination of the harmful algal blooms that occur in TSB and its surroundings.

  16. Photochemical trajectory modelling studies of the 1987 Antarctic spring vortex

    NASA Technical Reports Server (NTRS)

    Austin, J.; Jones, R. L.; Mckenna, D. S.

    1988-01-01

    Simulations of Antarctic ozone photochemistry performed using a photochemical model integrated along air parcel trajectories are described. This type of model has a major advantage at high latitudes of being able to simulate correctly the complex interaction between photolysis and temperature fields, which, because of the polar night cannot be represented accurately in a zonally averaged framework. Isentropic air parcel trajectories were computed using Meteorological Office global model analyses and forecast fields from positions along the ER-2 flight paths during the Airborne Antarctic Ozone Experiment in Austral Spring 1987. A photochemical model is integrated along these trajectories using the aircraft observations to initialize constituent concentrations. The model includes additional reactions of the ClO dimer and also bromine reactions, which are thought to play a significant role in Antarctica. The model also includes heterogeneous reactions which are invoked when the air parcel passes through a polar stratospheric cloud (PSC). The existence of a PSC is determined throughout the course of the model integration from the parcel temperature and the saturated vapour pressure of water over an assumed H2O/HNO3 mixture. The air parcel temperature is used to determine the saturated vapor pressure of HNO3 over the same mixture. Mixing ratios which exceed saturation result in condensation of the excess in the model and hence lead to a reduction of the amount of gas phase NO2 available for chemical reaction.

  17. A simple parcel method for prediction of cumulus onset and area-averaged cloud amount over heterogeneous land surfaces

    NASA Technical Reports Server (NTRS)

    Wetzel, Peter J.

    1990-01-01

    A set of PBL data selected from the Wangara experiment is used to examine the relationship between cumulus amount and the calculated relative humidity of rising parcels. The Wilde et al. (1985) method is compared to two explicit parcel methods. It is shown that predictions using parcel methods, in which surface air is lifted to its equilibrium level while being diluted by a defined amount of mixed layer air, are superior for cloud amount, especially during periods of rapid cloud onset when the mean boundary layer top is swiftly rising through a near-neutral layer. Pending independent verification, it appears that an rms error in instantaneous cloud amount of + or - 10 percent may be achievable.

  18. Gyral parcellation of cortical surfaces via coupled flow field tracking

    NASA Astrophysics Data System (ADS)

    Li, Gang; Guo, Lei; Li, Kaiming; Nie, Jingxin; Liu, Tianming

    2010-03-01

    This paper presents a novel method for parcellation of the cortical surface of human brain into gyral based regions via coupled flow field tracking. The proposed method consists of two major steps. First, the cortical surface is automatically parcellated into sulcal based regions using several procedures: estimating principal curvatures and principal directions; applying the hidden Markov random field and the Expectation-Maximization (HMRF-EM) framework for sulcal region segmentation based on the maximum principal curvature; diffusing the maximum principal direction field in order to propagate reliable and informative principal directions at gyral crests and sulcal bottoms to other flat cortical regions with noisy principal directions by minimization of an energy function; tracking the flow field towards sulcal bottoms to parcellate the cortical surfaces into sulcal basins. The sulcal parcellation provides a very good initialization for the following steps of gyral parcellation on cortical surfaces. Second, based on the sulcal parcellation results, the cortical surface is further parcellated into gyral based regions using the following procedures: extracting gyral crest segments; dilating gyral crest segments; inverting the principal direction flow field and tracking the flow field towards gyral crests in order to partition the cortical surface into a collection of gyral patches; merging gyral patches to obtain gyral parcellation of the cortical surface. The proposed algorithm pipeline is applied to nine randomly selected cortical surfaces of normal brains and promising results are obtained. The accuracy of the semi-automatic gyral parcellation is comparable to that labeled manually by experts.

  19. AIR INGRESS ANALYSIS: COMPUTATIONAL FLUID DYNAMIC MODELS

    SciTech Connect

    Chang H. Oh; Eung S. Kim; Richard Schultz; Hans Gougar; David Petti; Hyung S. Kang

    2010-08-01

    The Idaho National Laboratory (INL), under the auspices of the U.S. Department of Energy, is performing research and development that focuses on key phenomena important during potential scenarios that may occur in very high temperature reactors (VHTRs). Phenomena Identification and Ranking Studies to date have ranked an air ingress event, following on the heels of a VHTR depressurization, as important with regard to core safety. Consequently, the development of advanced air ingress-related models and verification and validation data are a very high priority. Following a loss of coolant and system depressurization incident, air will enter the core of the High Temperature Gas Cooled Reactor through the break, possibly causing oxidation of the in-the core and reflector graphite structure. Simple core and plant models indicate that, under certain circumstances, the oxidation may proceed at an elevated rate with additional heat generated from the oxidation reaction itself. Under postulated conditions of fluid flow and temperature, excessive degradation of the lower plenum graphite can lead to a loss of structural support. Excessive oxidation of core graphite can also lead to the release of fission products into the confinement, which could be detrimental to a reactor safety. Computational fluid dynamic model developed in this study will improve our understanding of this phenomenon. This paper presents two-dimensional and three-dimensional CFD results for the quantitative assessment of the air ingress phenomena. A portion of results of the density-driven stratified flow in the inlet pipe will be compared with results of the experimental results.

  20. Shape-based multifeature brain parcellation

    NASA Astrophysics Data System (ADS)

    Nadeem, Saad; Kaufman, Arie

    2016-03-01

    We present a novel approach to parcellate - delineate the anatomical feature (folds, gyri, sulci) boundaries - the brain cortex. Our approach is based on extracting the 3D brain cortical surface mesh from magnetic resonance (MR) images, computing the shape measures (area, mean curvature, geodesic, and travel depths) for this mesh, and delineating the anatomical feature boundaries using these measures. We use angle-area preserving mapping of the cortical surface mesh to a simpler topology (disk or rectangle) to aid in the visualization and delineation of these boundaries. Contrary to commonly used generic 2D brain image atlas-based approaches, we use 3D surface mesh data extracted from a given brain MR imaging data and its specific shape measures for the parcellation. Our method does not require any non-linear registration of a given brain dataset to a generic atlas and hence, does away with the structure similarity assumption critical to the atlas-based approaches. We evaluate our approach using Mindboggle manually labeled brain datasets and achieve the following accuracies: 72.4% for gyri, 78.5% for major sulci, and 98.4% for folds. These results warrant further investigation of this approach as an alternative or as an initialization to the atlas-based approaches.

  1. Manual MRI parcellation of the frontal lobe.

    PubMed

    Ranta, Marin E; Crocetti, Deana; Clauss, Jacqueline A; Kraut, Michael A; Mostofsky, Stewart H; Kaufmann, Walter E

    2009-05-15

    The ability to examine associations between neuropsychiatric conditions and functionally relevant frontal lobe sub-regions is a fundamental goal in neuropsychiatry, but methods for identifying frontal sub-regions in MR (magnetic resonance) images are not well established. Prior published techniques have principally defined gyral regions that do not necessarily correspond to known functional divisions. We present a method in which sulcal-gyral landmarks are used to manually delimit functionally relevant regions within the frontal lobe: primary motor cortex, anterior cingulate, deep white matter, premotor cortex regions (supplementary motor complex (SMC), frontal eye field and lateral premotor cortex) and prefrontal cortex (PFC) regions (medial PFC, dorsolateral PFC (DLPFC), inferior PFC, lateral orbitofrontal cortex (OFC) and medial OFC). Feasibility was tested by applying the protocol to brain MR data from 15 boys with attention-deficit/hyperactivity disorder (ADHD) and 15 typically developing controls, 8-12 years old. Intra- and inter-rater intraclass correlation coefficients were calculated using parcellation volumes from a subset of that group. Inter-rater results for the 22 hemisphere specific sub-regions ranged from 0.724 to 0.997, with all but seven values above 0.9. Boys with ADHD showed significantly smaller left hemisphere SMC and DLPFC volumes after normalization for total cerebral volume. These findings support the method as a reliable and valid technique for parcellating the frontal lobe into functionally relevant sub-regions.

  2. Manual MRI parcellation of the frontal lobe

    PubMed Central

    Richardson, Marin E.; Crocetti, Deana; Clauss, Jacqueline A.; Kraut, Michael A.; Mostofsky, Stewart H.; Kaufmann, Walter E.

    2009-01-01

    The ability to examine associations between neuropsychiatric conditions and functionally relevant frontal lobe sub-regions is a fundamental goal in neuropsychiatry, but methods for identifying frontal sub-regions in MR (magnetic resonance) images are not well established. Prior published techniques have principally defined gyral regions that do not necessarily correspond to known functional divisions. We present a method in which sulcal-gyral landmarks are used to manually delimit functionally relevant regions within the frontal lobe: primary motor cortex, anterior cingulate, deep white matter, premotor cortex regions (supplementary motor complex (SMC), frontal eye field and lateral premotor cortex) and prefrontal cortex (PFC) regions (medial PFC, dorsolateral PFC (DLPFC), inferior PFC, lateral orbitofrontal cortex (OFC) and medial OFC). Feasibility was tested by applying the protocol to brain MR data from 15 boys with ADHD and 15 typically developing controls, 8–12 years old. Intra- and inter-rater intraclass correlation coefficients were calculated using parcellation volumes from a subset of that group. Inter-rater results for the 22 hemisphere specific sub-regions ranged from 0.724 to 0.997, with all but six values above 0.9. Boys with ADHD showed significantly smaller left hemisphere SMC and DLPFC volumes after normalization for total cerebral volume. These findings support the method as a reliable and valid technique for parcellating the frontal lobe into functionally relevant subregions. PMID:19324532

  3. QUANTIFYING SUBGRID POLLUTANT VARIABILITY IN EULERIAN AIR QUALITY MODELS

    EPA Science Inventory

    In order to properly assess human risk due to exposure to hazardous air pollutants or air toxics, detailed information is needed on the location and magnitude of ambient air toxic concentrations. Regional scale Eulerian air quality models are typically limited to relatively coar...

  4. Air Pollution Data for Model Evaluation and Application

    EPA Science Inventory

    One objective of designing an air pollution monitoring network is to obtain data for evaluating air quality models that are used in the air quality management process and scientific discovery.1.2 A common use is to relate emissions to air quality, including assessing ...

  5. 75 FR 52378 - Transfer of Commercial Standard Mail Parcels to Competitive Product List

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-08-25

    ... Commission to transfer commercial Standard Mail Parcels from the Mail Classification Schedule's Market... to transfer commercial Standard Mail Parcels from the Mail Classification Schedule's Market Dominant... Commercial Standard Mail Parcels to Competitive Product List AGENCY: Postal Service. TM ACTION:...

  6. 7 CFR 1955.140 - Sale in parcels.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... 7 Agriculture 14 2011-01-01 2011-01-01 false Sale in parcels. 1955.140 Section 1955.140...) PROGRAM REGULATIONS (CONTINUED) PROPERTY MANAGEMENT Disposal of Inventory Property General § 1955.140 Sale... Programs property, may be offered for sale as a whole or subdivided into parcels as determined by the...

  7. 19. John and James Dobson Carpet Mills, West parcel, topographical ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    19. John and James Dobson Carpet Mills, West parcel, topographical plan, 1986. Barton and Martin, Engineers. 'Topographical Plan for Dobson Mills.' Prepared for Rouse Urban Housing, Inc., Philadelphia, Pennsylvania, 1986. - John & James Dobson Carpet Mill (West Parcel), 4041-4055 Ridge Avenue, Philadelphia, Philadelphia County, PA

  8. 12. John and James Dobson Carpet Mill, West Parcel, site ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    12. John and James Dobson Carpet Mill, West Parcel, site plan-upper right, and surrounding environs, 1884. Hopkins, Griffith Morgan. City Atlas of Philadelphia by Wards, 7 vols., Philadelphia, Pennsylvania: G. M. Hopkins and Co., 1884, Plate 9. - John & James Dobson Carpet Mill (West Parcel), 4041-4055 Ridge Avenue, Philadelphia, Philadelphia County, PA

  9. 48 CFR 242.1404-1 - Parcel post eligible shipments.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 48 Federal Acquisition Regulations System 3 2010-10-01 2010-10-01 false Parcel post eligible shipments. 242.1404-1 Section 242.1404-1 Federal Acquisition Regulations System DEFENSE ACQUISITION... Traffic and Transportation Management 242.1404-1 Parcel post eligible shipments. (b)(1) See DoD...

  10. 48 CFR 242.1404-1 - Parcel post eligible shipments.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 48 Federal Acquisition Regulations System 3 2011-10-01 2011-10-01 false Parcel post eligible shipments. 242.1404-1 Section 242.1404-1 Federal Acquisition Regulations System DEFENSE ACQUISITION... Traffic and Transportation Management 242.1404-1 Parcel post eligible shipments. (b)(1) See DoD...

  11. On the Origin of Polar Vortex Air

    NASA Technical Reports Server (NTRS)

    Rosenfield, J. E.; Schoeberl, M. R.; Einaudi, Franco (Technical Monitor)

    2001-01-01

    The existence of the multi-year HALOE CH4 data set, together with some comparisons of forward with back trajectory calculations which we have carried out, has motivated us to reexamine the question of polar vortex descent. Three-dimensional diabatic trajectory calculations have been carried out for the seven month fall to spring period in both the northern hemisphere (NH) and southern hemisphere (SH) polar stratosphere for the years 1992-1999. These computations are compared to fixed descent computations where the parcels were fixed at their latitude-longitude locations and allowed to descend without circulating. The forward trajectory computed descent is always less than the fixed descent due to horizontal parcel motions and variations in heating rates with latitude and longitude. Although the forward calculations estimate the maximum amount of descent that can occur, they do not necessarily indicate the actual origin of springtime vortex air. This is because more equator-ward air can be entrained within the vortex during its formation. To examine the origin of the springtime vortex air, the trajectory model was run backward for seven months from spring to fall. The back trajectories show a complex distribution of parcels in which one population originates in the upper stratosphere and mesosphere and experiences considerable descent in the polar regions, while the remaining parcels originate at lower altitudes of the middle and lower stratosphere and are mixed into the polar regions during vortex formation without experiencing as much vertical transport. The amount of descent experienced by the first population shows little variability from year to year, while the computed descent and mixing of the remaining parcels show considerable interannual variability due to the varying polar meteorology. Because of this complex parcel distribution it is not meaningful to speak of a net amount of descent experienced over the entire winter period. Since the back trajectories

  12. Parcellating Cortical Functional Networks in Individuals

    PubMed Central

    Wang, Danhong; Buckner, Randy L.; Fox, Michael D.; Holt, Daphne J.; Holmes, Avram J.; Stoecklein, Sophia; Langs, Georg; Pan, Ruiqi; Qian, Tianyi; Li, Kuncheng; Baker, Justin T.; Stufflebeam, Steven M.; Wang, Kai; Wang, Xiaomin; Hong, Bo; Liu, Hesheng

    2015-01-01

    The capacity to identify the unique functional architecture of an individual’s brain is a critical step towards personalized medicine and understanding the neural basis of variations in human cognition and behavior. Here, we developed a novel cortical parcellation approach to accurately map functional organization at the individual level using resting-state fMRI. A population-based functional atlas and a map of inter-individual variability were employed to guide the iterative search for functional networks in individual subjects. Functional networks mapped by this approach were highly reproducible within subjects and effectively captured the variability across subjects, including individual differences in brain lateralization. The algorithm performed well across different subject populations and data types including task fMRI data. The approach was then validated by invasive cortical stimulation mapping in surgical patients, suggesting great potential for use in clinical applications. PMID:26551545

  13. Advanced air revitalization system modeling and testing

    NASA Technical Reports Server (NTRS)

    Dall-Baumann, Liese; Jeng, Frank; Christian, Steve; Edeer, Marybeth; Lin, Chin

    1990-01-01

    To support manned lunar and Martian exploration, an extensive evaluation of air revitalization subsystems (ARS) is being conducted. The major operations under study include carbon dioxide removal and reduction; oxygen and nitrogen production, storage, and distribution; humidity and temperature control; and trace contaminant control. A comprehensive analysis program based on a generalized block flow model was developed to facilitate the evaluation of various processes and their interaction. ASPEN PLUS was used in modelling carbon dioxide removal and reduction. Several life support test stands were developed to test new and existing technologies for their potential applicability in space. The goal was to identify processes which use compact, lightweight equipment and maximize the recovery of oxygen and water. The carbon dioxide removal test stands include solid amine/vacuum desorption (SAVD), regenerative silver oxide chemisorption, and electrochemical carbon dioxide concentration (EDC). Membrane-based carbon dioxide removal and humidity control, catalytic reduction of carbon dioxide, and catalytic oxidation of trace contaminants were also investigated.

  14. Automated MRI parcellation of the frontal lobe

    PubMed Central

    Ranta, Marin E.; Chen, Min; Crocetti, Deana; Prince, Jerry L.; Subramaniam, Krish; Fischl, Bruce; Kaufmann, Walter E.; Mostofsky, Stewart H.

    2014-01-01

    Examination of associations between specific disorders and physical properties of functionally relevant frontal lobe sub-regions is a fundamental goal in neuropsychiatry. Here we present and evaluate automated methods of frontal lobe parcellation with the programs FreeSurfer(FS) and TOADS-CRUISE(T-C), based on the manual method described in Ranta et al. (2009) in which sulcal-gyral landmarks were used to manually delimit functionally relevant regions within the frontal lobe: i.e., primary motor cortex, anterior cingulate, deep white matter, premotor cortex regions (supplementary motor complex, frontal eye field and lateral premotor cortex) and prefrontal cortex (PFC) regions (medial PFC, dorsolateral PFC, inferior PFC, lateral orbitofrontal cortex (OFC) and medial OFC). Dice's coefficient, a measure of overlap, and percent volume difference were used to measure the reliability between manual and automated delineations for each frontal lobe region. For FS, mean Dice's coefficient for all regions was 0.75 and percent volume difference was 21.2%. For T-C the mean Dice's coefficient was 0.77 and the mean percent volume difference for all regions was 20.2%. These results, along with a high degree of agreement between the two automated methods (mean Dice's coefficient = 0.81, percent volume difference = 12.4%) and a proof-of-principle group difference analysis that highlights the consistency and sensitivity of the automated methods, indicate that the automated methods are valid techniques for parcellation of the frontal lobe into functionally relevant sub-regions. Thus, the methodology has the potential to increase efficiency, statistical power and reproducibility for population analyses of neuropsychiatric disorders with hypothesized frontal lobe contributions. PMID:23897577

  15. CONCENTRATIONS OF TOXIC AIR POLLUTANTS IN THE U.S. SIMULATED BY AN AIR QUALITY MODEL

    EPA Science Inventory

    As part of the US National Air Toxics Assessment, we have applied the Community Multiscale Air Quality Model, CMAQ, to study the concentrations of twenty gas-phase, toxic, hazardous air pollutants (HAPs) in the atmosphere over the continental United States. We modified the Carbo...

  16. Exposure Modeling of Residential Air Exchange Rates for NEXUS Participants

    EPA Science Inventory

    Due to cost and participant burden of personal measurements, air pollution health studies often estimate exposures using local ambient air monitors. Since outdoor levels do not necessarily reflect personal exposures, we developed the Exposure Model for Individuals (EMI) to improv...

  17. Prediction Models are Basis for Rational Air Quality Control

    ERIC Educational Resources Information Center

    Daniels, Anders; Bach, Wilfrid

    1973-01-01

    An air quality control scheme employing meteorological diffusion, time averaging and frequency, and cost-benefit models is discussed. The methods outlined provide a constant feedback system for air quality control. Flow charts and maps are included. (BL)

  18. Exposure Modeling of Residential Air Exchange Rates for NEXUS Participants.

    EPA Science Inventory

    Due to cost and participant burden of personal measurements, air pollution health studies often estimate exposures using local ambient air monitors. Since outdoor levels do not necessarily reflect personal exposures, we developed the Exposure Model for Individuals (EMI) to improv...

  19. AIR QUALITY MODELING OF PM AND AIR TOXICS AT NEIGHBORHOOD SCALES

    EPA Science Inventory

    The current interest in fine particles and toxics pollutants provide an impetus for extending air quality modeling capability towards improving exposure modeling and assessments. Human exposure models require information on concentration derived from interpolation of observati...

  20. AIR QUALITY MODELING FOR THE TWENTY-FIRST CENTURY

    EPA Science Inventory

    This presentation describes recent and evolving advances in the science of numerical air quality simulation modeling. Emphasis is placed on new developments in particulate matter modeling and atmospheric chemistry, diagnostic modeling tools, and integrated modeling systems. New...

  1. Critique of the equivalent air altitude model.

    PubMed

    Conkin, Johnny; Wessel, James H

    2008-10-01

    The adverse effects of hypoxic hypoxia include acute mountain sickness (AMS), high altitude pulmonary edema, and high altitude cerebral edema. It has long been assumed that those manifestations are directly related to reduction in the inspired partial pressure of oxygen (P(I)O2). This assumption underlies the equivalent air altitude (EAA) model, which holds that combinations of barometric pressure (P(B)) and inspired fraction of O2 (F(I)O2) that produce the same P(I)O2 will result in identical physiological responses. However, a growing body of evidence seems to indicate that different combinations of P(B) and P(I)O2 may produce different responses to the same P(I)O2. To investigate this question with respect to AMS, we conducted a search of the literature using the terms hypobaric hypoxia, normobaric hypoxia, and hypobaric normoxia. The results suggest that the EAA model provides only an approximate description of isohypoxia, and that P(B) has an independent effect on hypoxia and AMS. A historical report from 1956 and 15 reports from 1983 to 2005 compare the same hypoxic P(I)O2 at different P(B) with respect to the development of hypoxia and AMS. These data provide evidence for an independent effect of P(B) on hypoxia and AMS, and thereby invalidate EAA as an ideal model of isohypoxia. Refinement of the EAA model is needed, in particular for applications to high altitude where supplemental O2 is inadequate to prevent hypoxic hypoxia. Adjustment through probabilistic statistical modeling to match the current limited experimental observations is one approach to a better isohypoxic model. PMID:18856188

  2. Modeling of an air-backed diaphragm in dynamic pressure sensors: Effects of the air cavity

    NASA Astrophysics Data System (ADS)

    Liu, Haijun; Olson, Douglas A.; Yu, Miao

    2014-12-01

    As the key structure of most dynamic pressure sensors, a diaphragm backed by an air cavity plays a critical role in the determination of sensor performance metrics. In this paper, we investigate the influence of air cavity length on the sensitivity and bandwidth. A continuum mechanics model neglecting the air viscous effect is first developed to capture the structural-acoustic coupling between a clamped circular diaphragm and a cylindrical backing air cavity. To facilitate sensor design, close-form approximations are obtained to calculate the static sensitivity and the fundamental natural frequency of the air-backed diaphragm. Parametric studies based on this analytical model show that the air cavity can change both the effective mass and the effective stiffness of the diaphragm. One new finding is that the natural frequency of the air-backed diaphragm behaves differently in three different cavity length ranges. In particular, due to the mass effect of the air cavity being dominant, it is shown for the first time that the natural frequency decreases when the cavity length decreases below a critical value in the short cavity range. Furthermore, a finite element method (FEM) model is developed to validate the continuum mechanics model and to study the damping effect of the air cavity. These results provide important design guidelines for dynamic pressure sensors with air-backed diaphragms.

  3. Evaluating NOx emission inventories for regulatory air quality modeling using satellite and air quality model data

    NASA Astrophysics Data System (ADS)

    Kemball-Cook, Susan; Yarwood, Greg; Johnson, Jeremiah; Dornblaser, Bright; Estes, Mark

    2015-09-01

    The purpose of this study was to assess the accuracy of NOx emissions in the Texas Commission on Environmental Quality's (TCEQ) State Implementation Plan (SIP) modeling inventories of the southeastern U.S. We used retrieved satellite tropospheric NO2 columns from the Ozone Monitoring Instrument (OMI) together with NO2 columns from the Comprehensive Air Quality Model with Extensions (CAMx) to make top-down NOx emissions estimates using the mass balance method. Two different top-down NOx emissions estimates were developed using the KNMI DOMINO v2.0 and NASA SP2 retrievals of OMI NO2 columns. Differences in the top-down NOx emissions estimates made with these two operational products derived from the same OMI radiance data were sufficiently large that they could not be used to constrain the TCEQ NOx emissions in the southeast. The fact that the two available operational NO2 column retrievals give such different top-down NOx emissions results is important because these retrievals are increasingly being used to diagnose air quality problems and to inform efforts to solve them. These results reflect the fact that NO2 column retrievals are a blend of measurements and modeled data and should be used with caution in analyses that will inform policy development. This study illustrates both benefits and challenges of using satellite NO2 data for air quality management applications. Comparison with OMI NO2 columns pointed the way toward improvements in the CAMx simulation of the upper troposphere, but further refinement of both regional air quality models and the NO2 column retrievals is needed before the mass balance and other emission inversion methods can be used to successfully constrain NOx emission inventories used in U.S. regulatory modeling.

  4. Impact of inherent meteorology uncertainty on air quality model predictions

    EPA Science Inventory

    It is well established that there are a number of different classifications and sources of uncertainties in environmental modeling systems. Air quality models rely on two key inputs, namely, meteorology and emissions. When using air quality models for decision making, it is impor...

  5. Good manufacturing practice for modelling air pollution: Quality criteria for computer models to calculate air pollution

    NASA Astrophysics Data System (ADS)

    Dekker, C. M.; Sliggers, C. J.

    To spur on quality assurance for models that calculate air pollution, quality criteria for such models have been formulated. By satisfying these criteria the developers of these models and producers of the software packages in this field can assure and account for the quality of their products. In this way critics and users of such (computer) models can gain a clear understanding of the quality of the model. Quality criteria have been formulated for the development of mathematical models, for their programming—including user-friendliness, and for the after-sales service, which is part of the distribution of such software packages. The criteria have been introduced into national and international frameworks to obtain standardization.

  6. Air

    MedlinePlus

    ... do to protect yourself from dirty air . Indoor air pollution and outdoor air pollution Air can be polluted indoors and it can ... this chart to see what things cause indoor air pollution and what things cause outdoor air pollution! Indoor ...

  7. A survey of air flow models for multizone structures

    SciTech Connect

    Feustel, H.E.; Dieris, J.

    1991-03-01

    Air flow models are used to simulate the rates of incoming and outgoing air flows for a building with known leakage under given weather and shielding conditions. Additional information about the flow paths and air-mass flows inside the building can only by using multizone air flow models. In order to obtain more information on multizone air flow models, a literature review was performed in 1984. A second literature review and a questionnaire survey performed in 1989, revealed the existence of 50 multizone air flow models, all developed since 1966, two of which are still under development. All these programs use similar flow equations for crack flow but differ in the versatility to describe the full range of flow phenomena and the algorithm provided for solving the set of nonlinear equations. This literature review was found that newer models are able to describe and simulate the ventilation systems and interrelation of mechanical and natural ventilation. 27 refs., 2 figs., 1 tab.

  8. Hydraulic Hybrid Parcel Delivery Truck Deployment, Testing & Demonstration

    SciTech Connect

    Gallo, Jean-Baptiste

    2014-03-07

    Although hydraulic hybrid systems have shown promise over the last few years, commercial deployment of these systems has primarily been limited to Class 8 refuse trucks. In 2005, the Hybrid Truck Users Forum initiated the Parcel Delivery Working Group including the largest parcel delivery fleets in North America. The goal of the working group was to evaluate and accelerate commercialization of hydraulic hybrid technology for parcel delivery vehicles. FedEx Ground, Purolator and United Parcel Service (UPS) took delivery of the world’s first commercially available hydraulic hybrid parcel delivery trucks in early 2012. The vehicle chassis includes a Parker Hannifin hydraulic hybrid drive system, integrated and assembled by Freightliner Custom Chassis Corp., with a body installed by Morgan Olson. With funding from the U.S. Department of Energy, CALSTART and its project partners assessed the performance, reliability, maintainability and fleet acceptance of three pre-production Class 6 hydraulic hybrid parcel delivery vehicles using information and data from in-use data collection and on-road testing. This document reports on the deployment of these vehicles operated by FedEx Ground, Purolator and UPS. The results presented provide a comprehensive overview of the performance of commercial hydraulic hybrid vehicles in parcel delivery applications. This project also informs fleets and manufacturers on the overall performance of hydraulic hybrid vehicles, provides insights on how the technology can be both improved and more effectively used. The key findings and recommendations of this project fall into four major categories: -Performance, -Fleet deployment, -Maintenance, -Business case. Hydraulic hybrid technology is relatively new to the market, as commercial vehicles have been introduced only in the past few years in refuse and parcel delivery applications. Successful demonstration could pave the way for additional purchases of hydraulic hybrid vehicles throughout the

  9. Joint Spectral Decomposition for the Parcellation of the Human Cerebral Cortex Using Resting-State fMRI.

    PubMed

    Arslan, Salim; Parisot, Sarah; Rueckert, Daniel

    2015-01-01

    Identification of functional connections within the human brain has gained a lot of attention due to its potential to reveal neural mechanisms. In a whole-brain connectivity analysis, a critical stage is the computation of a set of network nodes that can effectively represent cortical regions. To address this problem, we present a robust cerebral cortex parcellation method based on spectral graph theory and resting-state fMRI correlations that generates reliable parcellations at the single-subject level and across multiple subjects. Our method models the cortical surface in each hemisphere as a mesh graph represented in the spectral domain with its eigenvectors. We connect cortices of different subjects with each other based on the similarity of their connectivity profiles and construct a multi-layer graph, which effectively captures the fundamental properties of the whole group as well as preserves individual subject characteristics. Spectral decomposition of this joint graph is used to cluster each cortical vertex into a subregion in order to obtain whole-brain parcellations. Using rs-fMRI data collected from 40 healthy subjects, we show that our proposed algorithm computes highly reproducible parcellations across different groups of subjects and at varying levels of detail with an average Dice score of 0.78, achieving up to 9% better reproducibility compared to existing approaches. We also report that our group-wise parcellations are functionally more consistent, thus, can be reliably used to represent the population in network analyses.

  10. AIR TOXICS MODELING RESEARCH PROGRAM: AN OVERVIEW

    EPA Science Inventory

    This product is a Microsoft Powerpoint slide presentation which was given at the joint EPA Region 3 - Mid-Atlantic Regional Air Management Association (MARAMA) Air Toxic Summit in Philadelphia, Pennsylvania held from October 18, 2005 through October 20, 2005. The slide presentat...

  11. VALMET: a valley air pollution model. Final report. Revision 1

    SciTech Connect

    Whiteman, C.D.; Allwine, K.J.

    1985-04-01

    An air quality model is described for predicting air pollution concentrations in deep mountain valleys arising from nocturnal down-valley transport and diffusion of an elevated pollutant plume, and the fumigation of the plume on the valley floor and sidewalls after sunrise. Included is a technical description of the model, a discussion of the model's applications, the required model inputs, sample calculations and model outputs, and a full listing of the FORTRAN computer program. 55 refs., 27 figs., 6 tabs.

  12. What is Air? A Standard Model for Combustion Simulations

    SciTech Connect

    Cloutman, L D

    2001-08-01

    Most combustion devices utilize air as the oxidizer. Thus, reactive flow simulations of these devices require the specification of the composition of air as part of the physicochemical input. A mixture of only oxygen and nitrogen often is used, although in reality air is a more complex mixture of somewhat variable composition. We summarize some useful parameters describing a standard model of dry air. Then we consider modifications to include water vapor for creating the desired level of humidity. The ''minor'' constituents of air, especially argon and water vapor, can affect the composition by as much as about 5 percent in the mole fractions.

  13. 77 FR 4808 - Conference on Air Quality Modeling

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-01-31

    ... AGENCY Conference on Air Quality Modeling AGENCY: U.S. Environmental Protection Agency (EPA). ACTION: Notice of conference. SUMMARY: The EPA will be hosting the Tenth Conference on Air Quality Modeling on...; suggest alternatives and substitute language for your requested changes. Describe any assumptions...

  14. THE ATMOSPHERIC MODEL EVALUATION TOOL (AMET); AIR QUALITY MODULE

    EPA Science Inventory

    This presentation reviews the development of the Atmospheric Model Evaluation Tool (AMET) air quality module. The AMET tool is being developed to aid in the model evaluation. This presentation focuses on the air quality evaluation portion of AMET. Presented are examples of the...

  15. DEVELOPMENT AND ANALYSIS OF AIR QUALITY MODELING SIMULATIONS FOR HAZARDOUS AIR POLLUTANTS

    EPA Science Inventory

    The concentrations of five hazardous air pollutants were simulated using the Community Multi Scale Air Quality (CMAQ) modeling system. Annual simulations were performed over the continental United States for the entire year of 2001 to support human exposure estimates. Results a...

  16. The contrast model method for the thermodynamical calculation of air-air wet heat exchanger

    NASA Astrophysics Data System (ADS)

    Yuan, Xiugan; Mei, Fang

    1989-02-01

    The 'contrast model' method thermodynamic calculation of air-air crossflow wet heat exchangers with initial air condensation is presented. Contrast-model equations are derived from the actual heat exchanger equations as well as imaginary ones; it is then possible to proceed to a proof that the enthalpy efficiency of the contrast model equations is similar to the temperature efficiency of the dry heat exchanger. Conditions are noted under which it becomes possible to unify thermodynamic calculations for wet and dry heat exchangers.

  17. Bayesian Analysis of a Reduced-Form Air Quality Model

    EPA Science Inventory

    Numerical air quality models are being used for assessing emission control strategies for improving ambient pollution levels across the globe. This paper applies probabilistic modeling to evaluate the effectiveness of emission reduction scenarios aimed at lowering ground-level oz...

  18. INTERCOMPARISON OF ALTERNATIVE VEGETATION DATABASES FOR REGIONAL AIR QUALITY MODELING

    EPA Science Inventory

    Vegetation cover data are used to characterize several regional air quality modeling processes, including the calculation of heat, moisture, and momentum fluxes with the Mesoscale Meteorological Model (MM5) and the estimate of biogenic volatile organic compound and nitric oxide...

  19. Multi-Contrast Multi-Atlas Parcellation of Diffusion Tensor Imaging of the Human Brain

    PubMed Central

    Tang, Xiaoying; Yoshida, Shoko; Hsu, John; Huisman, Thierry A. G. M.; Faria, Andreia V.; Oishi, Kenichi; Kutten, Kwame; Poretti, Andrea; Li, Yue; Miller, Michael I.; Mori, Susumu

    2014-01-01

    In this paper, we propose a novel method for parcellating the human brain into 193 anatomical structures based on diffusion tensor images (DTIs). This was accomplished in the setting of multi-contrast diffeomorphic likelihood fusion using multiple DTI atlases. DTI images are modeled as high dimensional fields, with each voxel exhibiting a vector valued feature comprising of mean diffusivity (MD), fractional anisotropy (FA), and fiber angle. For each structure, the probability distribution of each element in the feature vector is modeled as a mixture of Gaussians, the parameters of which are estimated from the labeled atlases. The structure-specific feature vector is then used to parcellate the test image. For each atlas, a likelihood is iteratively computed based on the structure-specific vector feature. The likelihoods from multiple atlases are then fused. The updating and fusing of the likelihoods is achieved based on the expectation-maximization (EM) algorithm for maximum a posteriori (MAP) estimation problems. We first demonstrate the performance of the algorithm by examining the parcellation accuracy of 18 structures from 25 subjects with a varying degree of structural abnormality. Dice values ranging 0.8–0.9 were obtained. In addition, strong correlation was found between the volume size of the automated and the manual parcellation. Then, we present scan-rescan reproducibility based on another dataset of 16 DTI images – an average of 3.73%, 1.91%, and 1.79% for volume, mean FA, and mean MD respectively. Finally, the range of anatomical variability in the normal population was quantified for each structure. PMID:24809486

  20. Intercomparisons of AIRS Observations with MERRA Reanalysis and Climate Models

    NASA Astrophysics Data System (ADS)

    Hearty, T. J.; Vollmer, B.; Theobald, M.; Savtchenko, A. K.; Ding, F.; Esfandiari, A. E.; Ostrenga, D.; Bosilovich, M. G.; Fetzer, E.; Tian, B.; Fishbein, E.; Manning, E.; Yue, Q.

    2012-12-01

    We perform intercomparisons among AIRS (Atmospheric Infrared Sounder) observations, MERRA (Modern-Era Retrospective Analysis for Research and Applications) reanalysis, and CMIP5 models. One of the greatest challenges of using satellite observations from Low Earth Orbit (LEO) to evaluate climate models is to account for differences in the sampling. Climate models are sampled on a regular grid with equal increments in time and space while LEO satellite observations are not. Since AIRS is an infrared instrument its sampling is also affected by clouds. Version 6 of the AIRS processing algorithm will have improved accuracy and increased sampling over the Version 5 algorithm. We compare AIRS and MERRA data with identical sampling to assess how well the satellite observations and reanalysis Water Vapor, Temperature, and Clouds agree when they have the same sampling. Since Version 6 of the AIRS processing algorithms also have improved sampling we use MERRA sampled like AIRS to estimate the improvement in the sampling bias between AIRS Version 5 and Version 6 Results. While the uncertainties in the current generation of climate models are larger than the sampling uncertainties, as the models improve more careful intercomparisons will be necessary. Therefore we compare the differences between AIRS observations and CMIP5 Climate Models to assess the significance of the sampling uncertainties.

  1. Modelling of air pressure effects in casting moulds

    NASA Astrophysics Data System (ADS)

    Attar, E.; Homayonifar, P.; Babaei, R.; Asgari, K.; Davami, P.

    2005-09-01

    In the casting process, as a mould is filled with molten metal, air escapes through the vents. Air pressure in the mould cavity has serious effects upon the filling behaviour such as surface profile of the molten metal and filling time. In this project a computational model was developed for calculation of air pressure during the mould filling. A 3D single phase code based on the SOLA-VOF algorithm was used for the prediction of the fluid flow. The ideal gas assumption, conservation of mass equation and Bernoulli law were used for the calculation of air pressure. A new algorithm was developed to interpolate air pressure on the surface cells. The creation of air pressure was correlated with the sizes of the vents and their locations. An experimental test was designed to verify the modelling results. Comparison between the experimental data and simulation results has shown a good agreement.

  2. Modeling, Monitoring and Fault Diagnosis of Spacecraft Air Contaminants

    NASA Technical Reports Server (NTRS)

    Ramirez, W. Fred; Skliar, Mikhail; Narayan, Anand; Morgenthaler, George W.; Smith, Gerald J.

    1996-01-01

    Progress and results in the development of an integrated air quality modeling, monitoring, fault detection, and isolation system are presented. The focus was on development of distributed models of the air contaminants transport, the study of air quality monitoring techniques based on the model of transport process and on-line contaminant concentration measurements, and sensor placement. Different approaches to the modeling of spacecraft air contamination are discussed, and a three-dimensional distributed parameter air contaminant dispersion model applicable to both laminar and turbulent transport is proposed. A two-dimensional approximation of a full scale transport model is also proposed based on the spatial averaging of the three dimensional model over the least important space coordinate. A computer implementation of the transport model is considered and a detailed development of two- and three-dimensional models illustrated by contaminant transport simulation results is presented. The use of a well established Kalman filtering approach is suggested as a method for generating on-line contaminant concentration estimates based on both real time measurements and the model of contaminant transport process. It is shown that high computational requirements of the traditional Kalman filter can render difficult its real-time implementation for high-dimensional transport model and a novel implicit Kalman filtering algorithm is proposed which is shown to lead to an order of magnitude faster computer implementation in the case of air quality monitoring.

  3. Impact of the resolution of brain parcels on connectome-wide association studies in fMRI.

    PubMed

    Bellec, Pierre; Benhajali, Yassine; Carbonell, Felix; Dansereau, Christian; Albouy, Geneviève; Pelland, Maxime; Craddock, Cameron; Collignon, Oliver; Doyon, Julien; Stip, Emmanuel; Orban, Pierre

    2015-12-01

    A recent trend in functional magnetic resonance imaging is to test for association of clinical disorders with every possible connection between selected brain parcels. We investigated the impact of the resolution of functional brain parcels, ranging from large-scale networks to local regions, on a mass univariate general linear model (GLM) of connectomes. For each resolution taken independently, the Benjamini-Hochberg procedure controlled the false-discovery rate (FDR) at nominal level on realistic simulations. However, the FDR for tests pooled across all resolutions could be inflated compared to the FDR within resolution. This inflation was severe in the presence of no or weak effects, but became negligible for strong effects. We thus developed an omnibus test to establish the overall presence of true discoveries across all resolutions. Although not a guarantee to control the FDR across resolutions, the omnibus test may be used for descriptive analysis of the impact of resolution on a GLM analysis, in complement to a primary analysis at a predefined single resolution. On three real datasets with significant omnibus test (schizophrenia, congenital blindness, motor practice), markedly higher rate of discovery were obtained at low resolutions, below 50, in line with simulations showing increase in sensitivity at such resolutions. This increase in discovery rate came at the cost of a lower ability to localize effects, as low resolution parcels merged many different brain regions together. However, with 30 or more parcels, the statistical effect maps were biologically plausible and very consistent across resolutions. These results show that resolution is a key parameter for GLM-connectome analysis with FDR control, and that a functional brain parcellation with 30 to 50 parcels may lead to an accurate summary of full connectome effects with good sensitivity in many situations.

  4. Eight Year Climatologies from Observational (AIRS) and Model (MERRA) Data

    NASA Technical Reports Server (NTRS)

    Hearty, Thomas; Savtchenko, Andrey; Won, Young-In; Theobalk, Mike; Vollmer, Bruce; Manning, Evan; Smith, Peter; Ostrenga, Dana; Leptoukh, Greg

    2010-01-01

    We examine climatologies derived from eight years of temperature, water vapor, cloud, and trace gas observations made by the Atmospheric Infrared Sounder (AIRS) instrument flying on the Aqua satellite and compare them to similar climatologies constructed with data from a global assimilation model, the Modern Era Retrospective-Analysis for Research and Applications (MERRA). We use the AIRS climatologies to examine anomalies and trends in the AIRS data record. Since sampling can be an issue for infrared satellites in low earth orbit, we also use the MERRA data to examine the AIRS sampling biases. By sampling the MERRA data at the AIRS space-time locations both with and without the AIRS quality control we estimate the sampling bias of the AIRS climatology and the atmospheric conditions where AIRS has a lower sampling rate. While the AIRS temperature and water vapor sampling biases are small at low latitudes, they can be more than a few degrees in temperature or 10 percent in water vapor at higher latitudes. The largest sampling biases are over desert. The AIRS and MERRA data are available from the Goddard Earth Sciences Data and Information Services Center (GES DISC). The AIRS climatologies we used are available for analysis with the GIOVANNI data exploration tool. (see, http://disc.gsfc.nasa.gov).

  5. Earthquake Hazard Class Mapping by Parcel in Las Vegas Valley

    NASA Astrophysics Data System (ADS)

    Pancha, A.; Pullammanappallil, S.; Louie, J. N.; Hellmer, W. K.

    2011-12-01

    Clark County, Nevada completed the very first effort in the United States to map earthquake hazard class systematically through an entire urban area. The map is used in development and disaster response planning, in addition to its direct use for building code implementation and enforcement. The County contracted with the Nevada System of Higher Education to classify about 500 square miles including urban Las Vegas Valley, and exurban areas considered for future development. The Parcel Map includes over 10,000 surface-wave array measurements accomplished over three years using Optim's SeisOpt° ReMi measurement and processing techniques adapted for large scale data. These array measurements classify individual parcels on the NEHRP hazard scale. Parallel "blind" tests were conducted at 93 randomly selected sites. The rms difference between the Vs30 values yielded by the blind data and analyses and the Parcel Map analyses is 4.92%. Only six of the blind-test sites showed a difference with a magnitude greater than 10%. We describe a "C+" Class for sites with Class B average velocities but soft surface soil. The measured Parcel Map shows a clearly definable C+ to C boundary on the west side of the Valley. The C to D boundary is much more complex. Using the parcel map in computing shaking in the Valley for scenario earthquakes is crucial for obtaining realistic predictions of ground motions.

  6. Urban Air Quality Modelling with AURORA: Prague and Bratislava

    NASA Astrophysics Data System (ADS)

    Veldeman, N.; Viaene, P.; De Ridder, K.; Peelaerts, W.; Lauwaet, D.; Muhammad, N.; Blyth, L.

    2012-04-01

    The European Commission, in its strategy to protect the health of the European citizens, states that in order to assess the impact of air pollution on public health, information on long-term exposure to air pollution should be available. Currently, indicators of air quality are often being generated using measured pollutant concentrations. While air quality monitoring stations data provide accurate time series information at specific locations, air quality models have the advantage of being able to assess the spatial variability of air quality (for different resolutions) and predict air quality in the future based on different scenarios. When running such air quality models at a high spatial and temporal resolution, one can simulate the actual situation as closely as possible, allowing for a detailed assessment of the risk of exposure to citizens from different pollutants. AURORA (Air quality modelling in Urban Regions using an Optimal Resolution Approach), a prognostic 3-dimensional Eulerian chemistry-transport model, is designed to simulate urban- to regional-scale atmospheric pollutant concentration and exposure fields. The AURORA model also allows to calculate the impact of changes in land use (e.g. planting of trees) or of emission reduction scenario's on air quality. AURORA is currently being applied within the ESA atmospheric GMES service, PASODOBLE (http://www.myair-eu.org), that delivers information on air quality, greenhouse gases, stratospheric ozone, … At present there are two operational AURORA services within PASODOBLE. Within the "Air quality forecast service" VITO delivers daily air quality forecasts for Belgium at a resolution of 5 km and for the major Belgian cities: Brussels, Ghent, Antwerp, Liege and Charleroi. Furthermore forecast services are provided for Prague, Czech Republic and Bratislava, Slovakia, both at a resolution of 1 km. The "Urban/regional air quality assessment service" provides urban- and regional-scale maps (hourly resolution

  7. Improving Air-Conditioner and Heat Pump Modeling

    SciTech Connect

    Winkler, Jon

    2012-03-02

    This presentation describes a new approach to modeling residential air conditioners and heat pumps, which allows users to model systems by specifying only the more readily-available SEER/EER/HSPF-type metrics. Manufacturer data was used to generate full sets of model inputs for over 450 heat pumps and air conditioners. A sensitivity analysis identified which inputs can be safely defaulted “behind-the-scenes” without negatively impacting the reliability of energy simulations.

  8. Improving Air-Conditioner and Heat Pump Modeling (Presentation)

    SciTech Connect

    Winkler, J.

    2012-03-01

    A new approach to modeling residential air conditioners and heat pumps allows users to model systems by specifying only the more readily-available SEER/EER/HSPF-type metrics. Manufacturer data was used to generate full sets of model inputs for over 450 heat pumps and air conditioners. A sensitivity analysis identified which inputs can be safely defaulted 'behind-the-scenes' without negatively impacting the reliability of energy simulations.

  9. Using geometrical, textural, and contextual information of land parcels for classification of detailed urban land use

    USGS Publications Warehouse

    Wu, S.-S.; Qiu, X.; Usery, E.L.; Wang, L.

    2009-01-01

    Detailed urban land use data are important to government officials, researchers, and businesspeople for a variety of purposes. This article presents an approach to classifying detailed urban land use based on geometrical, textural, and contextual information of land parcels. An area of 6 by 14 km in Austin, Texas, with land parcel boundaries delineated by the Travis Central Appraisal District of Travis County, Texas, is tested for the approach. We derive fifty parcel attributes from relevant geographic information system (GIS) and remote sensing data and use them to discriminate among nine urban land uses: single family, multifamily, commercial, office, industrial, civic, open space, transportation, and undeveloped. Half of the 33,025 parcels in the study area are used as training data for land use classification and the other half are used as testing data for accuracy assessment. The best result with a decision tree classification algorithm has an overall accuracy of 96 percent and a kappa coefficient of 0.78, and two naive, baseline models based on the majority rule and the spatial autocorrelation rule have overall accuracy of 89 percent and 79 percent, respectively. The algorithm is relatively good at classifying single-family, multifamily, commercial, open space, and undeveloped land uses and relatively poor at classifying office, industrial, civic, and transportation land uses. The most important attributes for land use classification are the geometrical attributes, particularly those related to building areas. Next are the contextual attributes, particularly those relevant to the spatial relationship between buildings, then the textural attributes, particularly the semivariance texture statistic from 0.61-m resolution images.

  10. Recent Advances in WRF Modeling for Air Quality Applications

    EPA Science Inventory

    The USEPA uses WRF in conjunction with the Community Multiscale Air Quality (CMAQ) for air quality regulation and research. Over the years we have added physics options and geophysical datasets to the WRF system to enhance model capabilities especially for extended retrospective...

  11. Dispersion modeling of selected PAHs in urban air: A new approach combining dispersion model with GIS and passive air sampling

    NASA Astrophysics Data System (ADS)

    Sáňka, Ondřej; Melymuk, Lisa; Čupr, Pavel; Dvorská, Alice; Klánová, Jana

    2014-10-01

    This study introduces a new combined air concentration measurement and modeling approach that we propose can be useful in medium and long term air quality assessment. A dispersion study was carried out for four high molecular weight polycyclic aromatic hydrocarbons (PAHs) in an urban area with industrial, traffic and domestic heating sources. A geographic information system (GIS) was used both for processing of input data as well as visualization of the modeling results. The outcomes of the dispersion model were compared to the results of passive air sampling (PAS). Despite discrepancies between measured and modeled concentrations, an approach combining the two techniques is promising for future air quality assessment. Differences between measured and modeled concentrations, in particular when measured values exceed the modeled concentrations, are indicative of undocumented, sporadic pollutant sources. Thus, these differences can also be useful for assessing and refining emission inventories.

  12. Semi-automatic parcellation of the corpus striatum

    NASA Astrophysics Data System (ADS)

    Al-Hakim, Ramsey; Nain, Delphine; Levitt, James; Shenton, Martha; Tannenbaum, Allen

    2007-03-01

    The striatum is the input component of the basal ganglia from the cerebral cortex. It includes the caudate, putamen, and nucleus accumbens. Thus, the striatum is an important component in limbic frontal-subcortical circuitry and is believed to be relevant both for reward-guided behaviors and for the expression of psychosis. The dorsal striatum is composed of the caudate and putamen, both of which are further subdivided into pre- and post-commissural components. The ventral striatum (VS) is primarily composed of the nucleus accumbens. The striatum can be functionally divided into three broad regions: 1) a limbic; 2) a cognitive and 3) a sensor-motor region. The approximate corresponding anatomic subregions for these 3 functional regions are: 1) the VS; 2) the pre/post-commissural caudate and the pre-commissural putamen and 3) the post-commissural putamen. We believe assessing these subregions, separately, in disorders with limbic and cognitive impairment such as schizophrenia may yield more informative group differences in comparison with normal controls than prior parcellation strategies of the striatum such as assessing the caudate and putamen. The manual parcellation of the striatum into these subregions is currently defined using certain landmark points and geometric rules. Since identification of these areas is important to clinical research, a reliable and fast parcellation technique is required. Currently, only full manual parcellation using editing software is available; however, this technique is extremely time intensive. Previous work has shown successful application of heuristic rules into a semi-automatic platform1. We present here a semi-automatic algorithm which implements the rules currently used for manual parcellation of the striatum, but requires minimal user input and significantly reduces the time required for parcellation.

  13. A Physically Based Model for Air-Lift Pumping

    NASA Astrophysics Data System (ADS)

    FrançOis, Odile; Gilmore, Tyler; Pinto, Michael J.; Gorelick, Steven M.

    1996-08-01

    A predictive, physically based model for pumping water from a well using air injection (air-lift pumping) was developed for the range of flow rates that we explored in a series of laboratory experiments. The goal was to determine the air flow rate required to pump a specific flow rate of water in a given well, designed for in-well air stripping of volatile organic compounds from an aquifer. The model was validated against original laboratory data as well as data from the literature. A laboratory air-lift system was constructed that consisted of a 70-foot-long (21-m-long) pipe, 5.5 inches (14 cm) inside diameter, in which an air line of 1.3 inches (3.3 cm) outside diameter was placed with its bottom at different elevations above the base of the long pipe. Experiments were conducted for different levels of submergence, with water-pumping rates ranging from 5 to 70 gallons/min (0.32-4.4 L/s), and air flow ranging from 7 to 38 standard cubic feet/min (0.2-1.1 m3 STP/min). The theoretical approach adopted in the model was based on an analysis of the system as a one-dimensional two-phase flow problem. The expression for the pressure gradient includes inertial energy terms, friction, and gas expansion versus elevation. Data analysis revealed that application of the usual drift-flux model to estimate the air void fraction is not adequate for the observed flow patterns: either slug or churn flow. We propose a modified drift-flux model that accurately predicts air-lift pumping requirements for a range of conditions representative of in-well air-stripping operations.

  14. Modeling air quality over China: Results from the Panda project

    NASA Astrophysics Data System (ADS)

    Katinka Petersen, Anna; Bouarar, Idir; Brasseur, Guy; Granier, Claire; Xie, Ying; Wang, Lili; Wang, Xuemei

    2015-04-01

    China faces strong air pollution problems related to rapid economic development in the past decade and increasing demand for energy. Air quality monitoring stations often report high levels of particle matter and ozone all over the country. Knowing its long-term health impacts, air pollution became then a pressing problem not only in China but also in other Asian countries. The PANDA project is a result of cooperation between scientists from Europe and China who joined their efforts for a better understanding of the processes controlling air pollution in China, improve methods for monitoring air quality and elaborate indicators in support of European and Chinese policies. A modeling system of air pollution is being setup within the PANDA project and include advanced global (MACC, EMEP) and regional (WRF-Chem, EMEP) meteorological and chemical models to analyze and monitor air quality in China. The poster describes the accomplishments obtained within the first year of the project. Model simulations for January and July 2010 are evaluated with satellite measurements (SCIAMACHY NO2 and MOPITT CO) and in-situ data (O3, CO, NOx, PM10 and PM2.5) observed at several surface stations in China. Using the WRF-Chem model, we investigate the sensitivity of the model performance to emissions (MACCity, HTAPv2), horizontal resolution (60km, 20km) and choice of initial and boundary conditions.

  15. A FEDERATED PARTNERSHIP FOR URBAN METEOROLOGICAL AND AIR QUALITY MODELING

    EPA Science Inventory

    Recently, applications of urban meteorological and air quality models have been performed at resolutions on the order of km grid sizes. This necessitated development and incorporation of high resolution landcover data and additional boundary layer parameters that serve to descri...

  16. Incorporating principal component analysis into air quality model evaluation

    EPA Science Inventory

    The efficacy of standard air quality model evaluation techniques is becoming compromised as the simulation periods continue to lengthen in response to ever increasing computing capacity. Accordingly, the purpose of this paper is to demonstrate a statistical approach called Princi...

  17. Control of asthma triggers in indoor air with air cleaners: a modeling analysis

    PubMed Central

    Myatt, Theodore A; Minegishi, Taeko; Allen, Joseph G; MacIntosh, David L

    2008-01-01

    Background Reducing exposure to environmental agents indoors shown to increase asthma symptoms or lead to asthma exacerbations is an important component of a strategy to manage asthma for individuals. Numerous investigations have demonstrated that portable air cleaning devices can reduce concentrations of asthma triggers in indoor air; however, their benefits for breathing problems have not always been reproducible. The potential exposure benefits of whole house high efficiency in-duct air cleaners for sensitive subpopulations have yet to be evaluated. Methods We used an indoor air quality modeling system (CONTAM) developed by NIST to examine peak and time-integrated concentrations of common asthma triggers present in indoor air over a year as a function of natural ventilation, portable air cleaners, and forced air ventilation equipped with conventional and high efficiency filtration systems. Emission rates for asthma triggers were based on experimental studies published in the scientific literature. Results Forced air systems with high efficiency filtration were found to provide the best control of asthma triggers: 30–55% lower cat allergen levels, 90–99% lower risk of respiratory infection through the inhalation route of exposure, 90–98% lower environmental tobacco smoke (ETS) levels, and 50–75% lower fungal spore levels than the other ventilation/filtration systems considered. These results indicate that the use of high efficiency in-duct air cleaners provide an effective means of controlling allergen levels not only in a single room, like a portable air cleaner, but the whole house. Conclusion These findings are useful for evaluating potential benefits of high efficiency in-duct filtration systems for controlling exposure to asthma triggers indoors and for the design of trials of environmental interventions intended to evaluate their utility in practice. PMID:18684328

  18. Validation of a novel air toxic risk model with air monitoring.

    PubMed

    Pratt, Gregory C; Dymond, Mary; Ellickson, Kristie; Thé, Jesse

    2012-01-01

    Three modeling systems were used to estimate human health risks from air pollution: two versions of MNRiskS (for Minnesota Risk Screening), and the USEPA National Air Toxics Assessment (NATA). MNRiskS is a unique cumulative risk modeling system used to assess risks from multiple air toxics, sources, and pathways on a local to a state-wide scale. In addition, ambient outdoor air monitoring data were available for estimation of risks and comparison with the modeled estimates of air concentrations. Highest air concentrations and estimated risks were generally found in the Minneapolis-St. Paul metropolitan area and lowest risks in undeveloped rural areas. Emissions from mobile and area (nonpoint) sources created greater estimated risks than emissions from point sources. Highest cancer risks were via ingestion pathway exposures to dioxins and related compounds. Diesel particles, acrolein, and formaldehyde created the highest estimated inhalation health impacts. Model-estimated air concentrations were generally highest for NATA and lowest for the AERMOD version of MNRiskS. This validation study showed reasonable agreement between available measurements and model predictions, although results varied among pollutants, and predictions were often lower than measurements. The results increased confidence in identifying pollutants, pathways, geographic areas, sources, and receptors of potential concern, and thus provide a basis for informing pollution reduction strategies and focusing efforts on specific pollutants (diesel particles, acrolein, and formaldehyde), geographic areas (urban centers), and source categories (nonpoint sources). The results heighten concerns about risks from food chain exposures to dioxins and PAHs. Risk estimates were sensitive to variations in methodologies for treating emissions, dispersion, deposition, exposure, and toxicity.

  19. Modeling of hydrogen-air diffusion flame

    NASA Technical Reports Server (NTRS)

    Isaac, K. M.

    1989-01-01

    An analytical and computational study of opposed jet diffusion flame for the purpose of understanding the effects of contaminants in the reactants and thermal diffusion of light species on extinction and reignition of diffusion flames is in progress. The methodologies that have been attempted so far are described. Results using a simple, one-step reaction for the hydrogen-air counterflow diffusion flame are presented. These results show the correct trends in the profiles of chemical species and temperature. The extinction limit can be clearly seen in the plot of temperature vs. Damkohler number.

  20. Scale Issues in Air Quality Modeling

    EPA Science Inventory

    This presentation reviews past model evaluation studies investigating the impact of horizontal grid spacing on model performance. It also presents several examples of using a spectral decomposition technique to separate the forcings from processes operating on different time scal...

  1. 76 FR 11297 - New Regional Ground Service for Parcels

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-03-01

    ...: The Commission is noticing a recently-filed Postal Service notice of rate and classification changes affecting Parcel Select. The changes involve a new offering identified as Regional Ground service. This notice informs the public of the filing, addresses preliminary procedural matters, and invites...

  2. United Parcel Service Evaluates Hybrid Electric Delivery Vans (Fact Sheet)

    SciTech Connect

    Not Available

    2010-02-01

    This fact sheet describes how the National Renewable Energy Laboratory's Fleet Test and Evaluation team evaluated the 12-month, in-service performance of six Class 4 hybrid electric delivery vans - fueled by regular diesel - and six comparable conventional diesel vans operated by the United Parcel Service.

  3. View of structures at rear of parcel with 12' scale ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    View of structures at rear of parcel with 12' scale (in tenths). From right: edge of Round House, Pencil house, Shell House, edge of School House. Heart Shrine made from mortared car headlights at frame left. Camera facing east. - Grandma Prisbrey's Bottle Village, 4595 Cochran Street, Simi Valley, Ventura County, CA

  4. 7 CFR 318.13-15 - Parcel post inspection.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... 7 Agriculture 5 2011-01-01 2011-01-01 false Parcel post inspection. 318.13-15 Section 318.13-15 Agriculture Regulations of the Department of Agriculture (Continued) ANIMAL AND PLANT HEALTH INSPECTION SERVICE, DEPARTMENT OF AGRICULTURE STATE OF HAWAII AND TERRITORIES QUARANTINE NOTICES Regulated...

  5. 7 CFR 318.13-15 - Parcel post inspection.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 7 Agriculture 5 2010-01-01 2010-01-01 false Parcel post inspection. 318.13-15 Section 318.13-15 Agriculture Regulations of the Department of Agriculture (Continued) ANIMAL AND PLANT HEALTH INSPECTION SERVICE, DEPARTMENT OF AGRICULTURE STATE OF HAWAII AND TERRITORIES QUARANTINE NOTICES Regulated...

  6. Center of parcel with picture tube wall along walkway. Leaning ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    Center of parcel with picture tube wall along walkway. Leaning Tower of Bottle Village at frame right; oblique view of Rumpus Room, remnants of Little Hut destroyed by Northridge earthquake at frame left. Camera facing northeast. - Grandma Prisbrey's Bottle Village, 4595 Cochran Street, Simi Valley, Ventura County, CA

  7. 7 CFR 318.13-15 - Parcel post inspection.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... 7 Agriculture 5 2012-01-01 2012-01-01 false Parcel post inspection. 318.13-15 Section 318.13-15 Agriculture Regulations of the Department of Agriculture (Continued) ANIMAL AND PLANT HEALTH INSPECTION... subpart, to examine any such products that are found for insect infestation, and to notify the...

  8. A multi-modal parcellation of human cerebral cortex.

    PubMed

    Glasser, Matthew F; Coalson, Timothy S; Robinson, Emma C; Hacker, Carl D; Harwell, John; Yacoub, Essa; Ugurbil, Kamil; Andersson, Jesper; Beckmann, Christian F; Jenkinson, Mark; Smith, Stephen M; Van Essen, David C

    2016-08-11

    Understanding the amazingly complex human cerebral cortex requires a map (or parcellation) of its major subdivisions, known as cortical areas. Making an accurate areal map has been a century-old objective in neuroscience. Using multi-modal magnetic resonance images from the Human Connectome Project (HCP) and an objective semi-automated neuroanatomical approach, we delineated 180 areas per hemisphere bounded by sharp changes in cortical architecture, function, connectivity, and/or topography in a precisely aligned group average of 210 healthy young adults. We characterized 97 new areas and 83 areas previously reported using post-mortem microscopy or other specialized study-specific approaches. To enable automated delineation and identification of these areas in new HCP subjects and in future studies, we trained a machine-learning classifier to recognize the multi-modal 'fingerprint' of each cortical area. This classifier detected the presence of 96.6% of the cortical areas in new subjects, replicated the group parcellation, and could correctly locate areas in individuals with atypical parcellations. The freely available parcellation and classifier will enable substantially improved neuroanatomical precision for studies of the structural and functional organization of human cerebral cortex and its variation across individuals and in development, aging, and disease. PMID:27437579

  9. Air Leakage of U.S. Homes: Model Prediction

    SciTech Connect

    Sherman, Max H.; McWilliams, Jennifer A.

    2007-01-01

    Air tightness is an important property of building envelopes. It is a key factor in determining infiltration and related wall-performance properties such as indoor air quality, maintainability and moisture balance. Air leakage in U.S. houses consumes roughly 1/3 of the HVAC energy but provides most of the ventilation used to control IAQ. The Lawrence Berkeley National Laboratory has been gathering residential air leakage data from many sources and now has a database of more than 100,000 raw measurements. This paper uses a model developed from that database in conjunction with US Census Bureau data for estimating air leakage as a function of location throughout the US.

  10. A diagnostic model for studying daytime urban air quality trends

    NASA Technical Reports Server (NTRS)

    Brewer, D. A.; Remsberg, E. E.; Woodbury, G. E.

    1981-01-01

    A single cell Eulerian photochemical air quality simulation model was developed and validated for selected days of the 1976 St. Louis Regional Air Pollution Study (RAPS) data sets; parameterizations of variables in the model and validation studies using the model are discussed. Good agreement was obtained between measured and modeled concentrations of NO, CO, and NO2 for all days simulated. The maximum concentration of O3 was also predicted well. Predicted species concentrations were relatively insensitive to small variations in CO and NOx emissions and to the concentrations of species which are entrained as the mixed layer rises.

  11. The Impact of the Parcel-Level Land Architecture on Land Surface Temperature in the Phoenix Metropolitan Area

    NASA Astrophysics Data System (ADS)

    LI, X.; Ouyang, Y.; Turner, B. L., II; Harlan, S.; Brazel, A.

    2014-12-01

    The relationship between land surface temperature (LST) and characteristics of the urban land system has received increasing attention in urban heat island research, especially for desert cities. The relationship between the land composition and LST has been widely studied. Such researches generally employ medium or coarser spatial resolution remotely sensed data and primarily focuses on the effects of one land cover type on the LST. In this study, we explore the effects of land system architecture - composition and configuration of different land-cover classes - on LST in the central Arizona-Phoenix metropolitan area at a fine-scale resolution, focused on the composition and configuration of single family residential parcels. A 1 m resolution land-cover map is used to calculate landscape metrics at the parcel level, and 6.8 m resolution data from the MODIS/ASTER are employed to retrieve LST. We introduce the socio-economic factors at neighborhood level as explanatory variables to help control for potential neighborhood effects. Multiple linear regression models examine the effects of landscape configuration on LST at the parcel scale, controlling for the effects of landscape composition and neighborhood characteristics. Results show that the configuration of parcels affects LST, revealing significant variable relationships between that architecture and LST at nighttime and daytime, and the role of the neighborhood effects on the outcomes.

  12. Impact of inherent meteorology uncertainty on air quality model predictions

    NASA Astrophysics Data System (ADS)

    Gilliam, Robert C.; Hogrefe, Christian; Godowitch, James M.; Napelenok, Sergey; Mathur, Rohit; Rao, S. Trivikrama

    2015-12-01

    It is well established that there are a number of different classifications and sources of uncertainties in environmental modeling systems. Air quality models rely on two key inputs, namely, meteorology and emissions. When using air quality models for decision making, it is important to understand how uncertainties in these inputs affect the simulated concentrations. Ensembles are one method to explore how uncertainty in meteorology affects air pollution concentrations. Most studies explore this uncertainty by running different meteorological models or the same model with different physics options and in some cases combinations of different meteorological and air quality models. While these have been shown to be useful techniques in some cases, we present a technique that leverages the initial condition perturbations of a weather forecast ensemble, namely, the Short-Range Ensemble Forecast system to drive the four-dimensional data assimilation in the Weather Research and Forecasting (WRF)-Community Multiscale Air Quality (CMAQ) model with a key focus being the response of ozone chemistry and transport. Results confirm that a sizable spread in WRF solutions, including common weather variables of temperature, wind, boundary layer depth, clouds, and radiation, can cause a relatively large range of ozone-mixing ratios. Pollutant transport can be altered by hundreds of kilometers over several days. Ozone-mixing ratios of the ensemble can vary as much as 10-20 ppb or 20-30% in areas that typically have higher pollution levels.

  13. The ASAC Air Carrier Investment Model (Third Generation)

    NASA Technical Reports Server (NTRS)

    Wingrove, Earl R., III; Gaier, Eric M.; Santmire, Tara E.

    1998-01-01

    To meet its objective of assisting the U.S. aviation industry with the technological challenges of the future, NASA must identify research areas that have the greatest potential for improving the operation of the air transportation system. To accomplish this, NASA is building an Aviation System Analysis Capability (ASAC). The ASAC differs from previous NASA modeling efforts in that the economic behavior of buyers and sellers in the air transportation and aviation industries is central to its conception. To link the economics of flight with the technology of flight, ASAC requires a parametrically based model with extensions that link airline operations and investments in aircraft with aircraft characteristics. This model also must provide a mechanism for incorporating air travel demand and profitability factors into the airlines' investment decisions. Finally, the model must be flexible and capable of being incorporated into a wide-ranging suite of economic and technical models flat are envisioned for ASAC.

  14. 76 FR 17784 - Forwarding and Return Service for Parcel Select Mailpieces

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-03-31

    ... 111 Forwarding and Return Service for Parcel Select Mailpieces AGENCY: Postal Service TM . ACTION... Parcel Select mailpieces and to eliminate the option to request discontinuance of forwarding. The Postal Service also implements a new price for Parcel Select forwards and returns; those pieces will now pay...

  15. 15 CFR 740.12 - Gift parcels and humanitarian donations (GFT).

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ...—(i) Item limitations—(A) Prohibited items. (1) For Cuba no items listed on the Commerce Control List... in gift parcels. (iii) Frequency. (A) Except for gift parcels of food to Cuba, not more than one gift... frequency limit on gift parcels of food to Cuba. (C) Parties seeking authorization to exceed the...

  16. A new model for investigating the mortality effects of multiple air pollutants in air pollution mortality time-series studies.

    PubMed

    Roberts, Steven

    2006-03-01

    Because the U.S. Environmental Protection Agency regulates air pollutants independently, the majority of time-series studies on air pollution and mortality have focused on estimating the adverse health effects of a single pollutant. However, due to the sometimes high correlation between air pollutants, the results from studies that focus on a single air pollutant can be difficult to interpret. In addition, the high correlation between air pollutants can produce problems of interpretation for the standard method of investigating the adverse health effects due to multiple air pollutants. The standard method involves simultaneously including the multiple air pollutants in a single statistical model. Because of this, the development of new models to concurrently estimate the adverse health effects of multiple air pollutants has recently been identified as an important area of future research. In this article, a new model for disentangling the joint effects of multiple air pollutants in air pollution mortality time-series studies is introduced. This new model uses the time-series data to assign each air pollutant a weight that indicates the pollutant's contribution to the air pollution mixture that affects mortality and to estimate the effect of this air pollution mixture on mortality. This model offers an improvement in statistical estimation precision over the standard method. It also avoids problems of interpretation that can occur if the standard method is used. This new model is then illustrated by applying it to time-series data from two U.S. counties.

  17. The ASAC Air Carrier Investment Model (Second Generation)

    NASA Technical Reports Server (NTRS)

    Wingrove, Earl R., III; Johnson, Jesse P.; Sickles, Robin C.; Good, David H.

    1997-01-01

    To meet its objective of assisting the U.S. aviation industry with the technological challenges of the future, NASA must identify research areas that have the greatest potential for improving the operation of the air transportation system. To accomplish this, NASA is building an Aviation System Analysis Capability (ASAC). The ASAC differs from previous NASA modeling efforts in that the economic behavior of buyers and sellers in the air transportation and aviation industries is central to its conception. To link the economics of flight with the technology of flight, ASAC requires a parametrically based mode with extensions that link airline operations and investments in aircraft with aircraft characteristics. This model also must provide a mechanism for incorporating air travel demand and profitability factors into the airlines' investment decisions. Finally, the model must be flexible and capable of being incorporated into a wide-ranging suite of economic and technical models that are envisioned for ASAC. We describe a second-generation Air Carrier Investment Model that meets these requirements. The enhanced model incorporates econometric results from the supply and demand curves faced by U.S.-scheduled passenger air carriers. It uses detailed information about their fleets in 1995 to make predictions about future aircraft purchases. It enables analysts with the ability to project revenue passenger-miles flown, airline industry employment, airline operating profit margins, numbers and types of aircraft in the fleet, and changes in aircraft manufacturing employment under various user-defined scenarios.

  18. Air-quality modelling in the Lake Baikal region.

    PubMed

    Van de Vel, Karen; Mensink, Clemens; De Ridder, Koen; Deutsch, Felix; Maes, Joachim; Vliegen, Jo; Aloyan, Artash; Yermakov, Alexander; Arutyunyan, Vardan; Khodzher, Tamara; Mijling, Bas

    2010-06-01

    In this paper, we assess the status of the air quality in the Lake Baikal region which is strongly influenced by the presence of anthropogenic pollution sources. We combined the local data, with global databases, remote sensing imagery and modelling tools. This approach allows to inventorise the air-polluting sources and to quantify the air-quality concentration levels in the Lake Baikal region to a reasonable level, despite the fact that local data are scarcely available. In the simulations, we focus on the month of July 2003, as for this period, validation data are available for a number of ground-based measurement stations within the Lake Baikal region.

  19. Air Quality Modeling in Support of the Near-Road Exposures and Effects of Urban Air Pollutants Study (NEXUS)

    EPA Science Inventory

    A major challenge in traffic-related air pollution exposure studies is the lack of information regarding pollutant exposure characterization. Air quality modeling can provide spatially and temporally varying exposure estimates for examining relationships between traffic-related a...

  20. Meteorological and air pollution modeling for an urban airport

    NASA Technical Reports Server (NTRS)

    Swan, P. R.; Lee, I. Y.

    1980-01-01

    Results are presented of numerical experiments modeling meteorology, multiple pollutant sources, and nonlinear photochemical reactions for the case of an airport in a large urban area with complex terrain. A planetary boundary-layer model which predicts the mixing depth and generates wind, moisture, and temperature fields was used; it utilizes only surface and synoptic boundary conditions as input data. A version of the Hecht-Seinfeld-Dodge chemical kinetics model is integrated with a new, rapid numerical technique; both the San Francisco Bay Area Air Quality Management District source inventory and the San Jose Airport aircraft inventory are utilized. The air quality model results are presented in contour plots; the combined results illustrate that the highly nonlinear interactions which are present require that the chemistry and meteorology be considered simultaneously to make a valid assessment of the effects of individual sources on regional air quality.

  1. Analytical model for contaminant mass removal by air sparging

    SciTech Connect

    Rabideau, A.J.; Blayden, J.M.

    1998-12-31

    An analytical model was developed to predict the removal of volatile organic compounds (VOCs) from ground water by air sparging (AS). The model treats the air sparging zone as a completely mixed reactor subject to the removal of dissolved contaminants by volatilization, advection, and first-order decay. Nonequilibrium desorption is approximated as a first-order mass transfer process. The model reproduces the tailing and rebound behavior often observed at AS sites, and would normally require the estimation of three site-specific parameters. Dimensional analysis demonstrates that predicting tailing can be interpreted in terms of kinetic desorption or diffusion of aqueous phase contaminants into discrete air channels. Related work is ongoing to test the model against field data.

  2. AN INDOOR AIR QUALITY MODEL FOR PARTICULATE MATTER

    EPA Science Inventory

    Thye paper discusses an indoor air quality (IAQ) model for particulate matter (PM). The standard for PM < 2.5 micrometers in aerodynamic diameter (PM 2.5) proposed by the U.S. EPA has produced considerable interest in indoor exposures to PM. IAQ models provide a useful tool for...

  3. Air Quality Modeling of Traffic-related Air Pollutants for the NEXUS Study

    EPA Science Inventory

    The paper presents the results of the model applications to estimate exposure metrics in support of an epidemiologic study in Detroit, Michigan. A major challenge in traffic-related air pollution exposure studies is the lack of information regarding pollutant exposure characteriz...

  4. Assessing The Policy Relevance of Regional Air Quality Models

    NASA Astrophysics Data System (ADS)

    Holloway, T.

    This work presents a framework for discussing the policy relevance of models, and regional air quality models in particular. We define four criteria: 1) The scientific status of the model; 2) Its ability to address primary environmental concerns; 3) The position of modeled environmental issues on the political agenda; and 4) The role of scientific input into the policy process. This framework is applied to current work simulating the transport of nitric acid in Asia with the ATMOS-N model, to past studies on air pollution transport in Europe with the EMEP model, and to future applications of the United States Environmental Protection Agency (US EPA) Models-3. The Lagrangian EMEP model provided critical input to the development of the 1994 Oslo and 1999 Gothenburg Protocols to the Convention on Long-Range Transbound- ary Air Pollution, as well as to the development of EU directives, via its role as a component of the RAINS integrated assessment model. Our work simulating reactive nitrogen in Asia follows the European example in part, with the choice of ATMOS-N, a regional Lagrangian model to calculate source-receptor relationships for the RAINS- Asia integrated assessment model. However, given differences between ATMOS-N and the EMEP model, as well as differences between the scientific and political cli- mates facing Europe ten years ago and Asia today, the role of these two models in the policy process is very different. We characterize the different aspects of policy relevance between these models using our framework, and consider how the current generation US EPA air quality model compares, in light of its Eulerian structure, dif- ferent objectives, and the policy context of the US.

  5. Spatial air pollution modelling for a West-African town.

    PubMed

    Gebreab, Sirak Zenebe; Vienneau, Danielle; Feigenwinter, Christian; Bâ, Hâmpaté; Cissé, Guéladio; Tsai, Ming-Yi

    2015-01-01

    Land use regression (LUR) modelling is a common approach used in European and Northern American epidemiological studies to assess urban and traffic related air pollution exposures. Studies applying LUR in Africa are lacking. A need exists to understand if this approach holds for an African setting, where urban features, pollutant exposures and data availability differ considerably from other continents. We developed a parsimonious regression model based on 48-hour nitrogen dioxide (NO2) concentrations measured at 40 sites in Kaédi, a medium sized West-African town, and variables generated in a geographic information system (GIS). Road variables and settlement land use characteristics were found to be important predictors of 48-hour NO2 concentration in the model. About 68% of concentration variability in the town was explained by the model. The model was internally validated by leave-one-out cross-validation and it was found to perform moderately well. Furthermore, its parameters were robust to sampling variation. We applied the model at 100 m pixels to create a map describing the broad spatial pattern of NO2 across Kaédi. In this research, we demonstrated the potential for LUR as a valid, cost-effective approach for air pollution modelling and mapping in an African town. If the methodology were to be adopted by environmental and public health authorities in these regions, it could provide a quick assessment of the local air pollution burden and potentially support air pollution policies and guidelines. PMID:26618306

  6. An updated model for millimeter wave propagation in moist air

    NASA Astrophysics Data System (ADS)

    Liebe, H. J.

    1985-10-01

    A practical atmospheric Millimeter-Wave Propagation Model is formulated that predicts attenuation, delay, and noise properties of moist air for frequencies up to 1000 GHz. Input variables are height distributions (0-30 km) of pressure, temperature, humidity, and suspended droplet concentration along an anticipated radio path. Spectroscopic data consists of more than 450 parameters describing local O2 and H2O absorption lines complemented by continuum spectra for dry air, water vapor, and hydrosols. For a model limited to frequencies below GHz, the number of spectroscopic parameters can be reduced to less than 200. Recent laboratory measurements at 138 GHz absolute attenuation rates for simulated air with water vapor pressures up to saturation allow the formulation of an improved, though empirical water vapor continuum. Model predictions are compared with selected (2.5-430 GHz) data from both laboratory and field experiments. In general, good agreement is obtained.

  7. Mathematical model of an air-filled alpha stirling refrigerator

    NASA Astrophysics Data System (ADS)

    McFarlane, Patrick; Semperlotti, Fabio; Sen, Mihir

    2013-10-01

    This work develops a mathematical model for an alpha Stirling refrigerator with air as the working fluid and will be useful in optimizing the mechanical design of these machines. Two pistons cyclically compress and expand air while moving sinusoidally in separate chambers connected by a regenerator, thus creating a temperature difference across the system. A complete non-linear mathematical model of the machine, including air thermodynamics, and heat transfer from the walls, as well as heat transfer and fluid resistance in the regenerator, is developed. Non-dimensional groups are derived, and the mathematical model is numerically solved. The heat transfer and work are found for both chambers, and the coefficient of performance of each chamber is calculated. Important design parameters are varied and their effect on refrigerator performance determined. This sensitivity analysis, which shows what the significant parameters are, is a useful tool for the design of practical Stirling refrigeration systems.

  8. Period adding cascades: experiment and modeling in air bubbling.

    PubMed

    Pereira, Felipe Augusto Cardoso; Colli, Eduardo; Sartorelli, José Carlos

    2012-03-01

    Period adding cascades have been observed experimentally/numerically in the dynamics of neurons and pancreatic cells, lasers, electric circuits, chemical reactions, oceanic internal waves, and also in air bubbling. We show that the period adding cascades appearing in bubbling from a nozzle submerged in a viscous liquid can be reproduced by a simple model, based on some hydrodynamical principles, dealing with the time evolution of two variables, bubble position and pressure of the air chamber, through a system of differential equations with a rule of detachment based on force balance. The model further reduces to an iterating one-dimensional map giving the pressures at the detachments, where time between bubbles come out as an observable of the dynamics. The model has not only good agreement with experimental data, but is also able to predict the influence of the main parameters involved, like the length of the hose connecting the air supplier with the needle, the needle radius and the needle length.

  9. Joint space-time geostatistical model for air quality surveillance

    NASA Astrophysics Data System (ADS)

    Russo, A.; Soares, A.; Pereira, M. J.

    2009-04-01

    Air pollution and peoples' generalized concern about air quality are, nowadays, considered to be a global problem. Although the introduction of rigid air pollution regulations has reduced pollution from industry and power stations, the growing number of cars on the road poses a new pollution problem. Considering the characteristics of the atmospheric circulation and also the residence times of certain pollutants in the atmosphere, a generalized and growing interest on air quality issues led to research intensification and publication of several articles with quite different levels of scientific depth. As most natural phenomena, air quality can be seen as a space-time process, where space-time relationships have usually quite different characteristics and levels of uncertainty. As a result, the simultaneous integration of space and time is not an easy task to perform. This problem is overcome by a variety of methodologies. The use of stochastic models and neural networks to characterize space-time dispersion of air quality is becoming a common practice. The main objective of this work is to produce an air quality model which allows forecasting critical concentration episodes of a certain pollutant by means of a hybrid approach, based on the combined use of neural network models and stochastic simulations. A stochastic simulation of the spatial component with a space-time trend model is proposed to characterize critical situations, taking into account data from the past and a space-time trend from the recent past. To identify near future critical episodes, predicted values from neural networks are used at each monitoring station. In this paper, we describe the design of a hybrid forecasting tool for ambient NO2 concentrations in Lisbon, Portugal.

  10. Modeling urban air pollution with optimized hierarchical fuzzy inference system.

    PubMed

    Tashayo, Behnam; Alimohammadi, Abbas

    2016-10-01

    Environmental exposure assessments (EEA) and epidemiological studies require urban air pollution models with appropriate spatial and temporal resolutions. Uncertain available data and inflexible models can limit air pollution modeling techniques, particularly in under developing countries. This paper develops a hierarchical fuzzy inference system (HFIS) to model air pollution under different land use, transportation, and meteorological conditions. To improve performance, the system treats the issue as a large-scale and high-dimensional problem and develops the proposed model using a three-step approach. In the first step, a geospatial information system (GIS) and probabilistic methods are used to preprocess the data. In the second step, a hierarchical structure is generated based on the problem. In the third step, the accuracy and complexity of the model are simultaneously optimized with a multiple objective particle swarm optimization (MOPSO) algorithm. We examine the capabilities of the proposed model for predicting daily and annual mean PM2.5 and NO2 and compare the accuracy of the results with representative models from existing literature. The benefits provided by the model features, including probabilistic preprocessing, multi-objective optimization, and hierarchical structure, are precisely evaluated by comparing five different consecutive models in terms of accuracy and complexity criteria. Fivefold cross validation is used to assess the performance of the generated models. The respective average RMSEs and coefficients of determination (R (2)) for the test datasets using proposed model are as follows: daily PM2.5 = (8.13, 0.78), annual mean PM2.5 = (4.96, 0.80), daily NO2 = (5.63, 0.79), and annual mean NO2 = (2.89, 0.83). The obtained results demonstrate that the developed hierarchical fuzzy inference system can be utilized for modeling air pollution in EEA and epidemiological studies.

  11. AQA - Air Quality model for Austria - Evaluation and Developments

    NASA Astrophysics Data System (ADS)

    Hirtl, M.; Krüger, B. C.; Baumann-Stanzer, K.; Skomorowski, P.

    2009-04-01

    The regional weather forecast model ALADIN of the Central Institute for Meteorology and Geodynamics (ZAMG) is used in combination with the chemical transport model CAMx (www.camx.com) to conduct forecasts of gaseous and particulate air pollution over Europe. The forecasts which are done in cooperation with the University of Natural Resources and Applied Life Sciences in Vienna (BOKU) are supported by the regional governments since 2005 with the main interest on the prediction of tropospheric ozone. The daily ozone forecasts are evaluated for the summer 2008 with the observations of about 150 air quality stations in Austria. In 2008 the emission-model SMOKE was integrated into the modelling system to calculate the biogenic emissions. The anthropogenic emissions are based on the newest EMEP data set as well as on regional inventories for the core domain. The performance of SMOKE is shown for a summer period in 2007. In the frame of the COST-action 728 „Enhancing mesoscale meteorological modelling capabilities for air pollution and dispersion applications", multi-model ensembles are used to conduct an international model evaluation. The model calculations of meteorological- and concentration fields are compared to measurements on the ensemble platform at the Joint Research Centre (JRC) in Ispra. The results for 2 episodes in 2006 show the performance of the different models as well as of the model ensemble.

  12. Air Quality Model System For The Vienna/bratislava Region

    NASA Astrophysics Data System (ADS)

    Krüger, B. C.; Schmittner, W.; Kromp-Kolb, H.

    A model system has been build up, consisting of the mesoscale meteorological fore- cast model MM5 and the chemical air-quality model CAMx. The coarse grid covers central Europe. By nesting, a spatial resolution of 3 km is reached for the core area, which includes the cities of Vienna (Austria) and Bratislava (Slovakia). In a first approach, the model system has been applied to a 6-day period in Febru- ary 1997, which was characterized by stagnant meteorological conditions. During this episode, primary pollutants like CO and NO2 have been compared with ambient mea- surements for the validation of the new model system. In the future it is foreseen to improve the spatial resolution, to apply the model system also for ozone and particulates, and to utilize it for a short-time forecast of air-quality parameters.

  13. Modeling the Environmental Impact of Air Traffic Operations

    NASA Technical Reports Server (NTRS)

    Chen, Neil

    2011-01-01

    There is increased interest to understand and mitigate the impacts of air traffic on the climate, since greenhouse gases, nitrogen oxides, and contrails generated by air traffic can have adverse impacts on the climate. The models described in this presentation are useful for quantifying these impacts and for studying alternative environmentally aware operational concepts. These models have been developed by leveraging and building upon existing simulation and optimization techniques developed for the design of efficient traffic flow management strategies. Specific enhancements to the existing simulation and optimization techniques include new models that simulate aircraft fuel flow, emissions and contrails. To ensure that these new models are beneficial to the larger climate research community, the outputs of these new models are compatible with existing global climate modeling tools like the FAA's Aviation Environmental Design Tool.

  14. Modeling of membrane processes for air revitalization and water recovery

    NASA Technical Reports Server (NTRS)

    Lange, Kevin E.; Foerg, Sandra L.; Dall-Bauman, Liese A.

    1992-01-01

    Gas-separation and reverse-osmosis membrane models are being developed in conjunction with membrane testing at NASA JSC. The completed gas-separation membrane model extracts effective component permeabilities from multicomponent test data, and predicts the effects of flow configuration, operating conditions, and membrane dimensions on module performance. Variable feed- and permeate-side pressures are considered. The model has been applied to test data for hollow-fiber membrane modules with simulated cabin-air feeds. Results are presented for a membrane designed for air drying applications. Extracted permeabilities are used to predict the effect of operating conditions on water enrichment in the permeate. A first-order reverse-osmosis model has been applied to test data for spiral wound membrane modules with a simulated hygiene water feed. The model estimates an effective local component rejection coefficient under pseudosteady-state conditions. Results are used to define requirements for a detailed reverse-osmosis model.

  15. Mathematical models for predicting indoor air quality from smoking activity.

    PubMed Central

    Ott, W R

    1999-01-01

    Much progress has been made over four decades in developing, testing, and evaluating the performance of mathematical models for predicting pollutant concentrations from smoking in indoor settings. Although largely overlooked by the regulatory community, these models provide regulators and risk assessors with practical tools for quantitatively estimating the exposure level that people receive indoors for a given level of smoking activity. This article reviews the development of the mass balance model and its application to predicting indoor pollutant concentrations from cigarette smoke and derives the time-averaged version of the model from the basic laws of conservation of mass. A simple table is provided of computed respirable particulate concentrations for any indoor location for which the active smoking count, volume, and concentration decay rate (deposition rate combined with air exchange rate) are known. Using the indoor ventilatory air exchange rate causes slightly higher indoor concentrations and therefore errs on the side of protecting health, since it excludes particle deposition effects, whereas using the observed particle decay rate gives a more accurate prediction of indoor concentrations. This table permits easy comparisons of indoor concentrations with air quality guidelines and indoor standards for different combinations of active smoking counts and air exchange rates. The published literature on mathematical models of environmental tobacco smoke also is reviewed and indicates that these models generally give good agreement between predicted concentrations and actual indoor measurements. PMID:10350523

  16. Mathematical model of one-man air revitalization system

    NASA Technical Reports Server (NTRS)

    1976-01-01

    A mathematical model was developed for simulating the steady state performance in electrochemical CO2 concentrators which utilize (NMe4)2 CO3 (aq.) electrolyte. This electrolyte, which accommodates a wide range of air relative humidity, is most suitable for one-man air revitalization systems. The model is based on the solution of coupled nonlinear ordinary differential equations derived from mass transport and rate equations for the processes which take place in the cell. The boundary conditions are obtained by solving the mass and energy transport equations. A shooting method is used to solve the differential equations.

  17. Modeling Air Stripping of Ammonia in an Agitated Vessel

    SciTech Connect

    Kofi, Adu-Wusu; Martino, Christopher J.; Wilmarth, William R.; Bennett, William M.; Peters, Robert s.

    2005-11-29

    A model has been developed to predict the rate of removal of ammonia (NH{sub 3}) from solution in a sparged agitated vessel. The model is first-order with respect to liquid-phase concentration of NH{sub 3}. The rate constant for the first-order equation is a function of parameters related to the vessel/impeller characteristics, the air/liquid properties as well as the process conditions. However, the vessel/impeller characteristics, the air/liquid properties, and the process conditions reduce the rate constant dependence to only three parameters, namely, the air sparge rate, the liquid volume or batch size, and the Henry's law constant of NH{sub 3} for the liquid or solution. Thus, the rate of removal is not mass-transfer limited. High air sparge rates, high temperatures, and low liquid volumes or batch sizes increase the rate of removal of NH{sub 3} from solution. The Henry's law constant effect is somewhat reflected in the temperature since Henry's law constant increases with increasing temperature. Data obtained from actual air stripping operation agree fairly well with the model predictions.

  18. Economic damages of ozone air pollution to crops using combined air quality and GIS modelling

    NASA Astrophysics Data System (ADS)

    Vlachokostas, Ch.; Nastis, S. A.; Achillas, Ch.; Kalogeropoulos, K.; Karmiris, I.; Moussiopoulos, N.; Chourdakis, E.; Banias, G.; Limperi, N.

    2010-09-01

    This study aims at presenting a combined air quality and GIS modelling methodological approach in order to estimate crop damages from photochemical air pollution, depict their spatial resolution and assess the order of magnitude regarding the corresponding economic damages. The analysis is conducted within the Greater Thessaloniki Area, Greece, a Mediterranean territory which is characterised by high levels of photochemical air pollution and considerable agricultural activity. Ozone concentration fields for 2002 and for specific emission reduction scenarios for the year 2010 were estimated with the Ozone Fine Structure model in the area under consideration. Total economic damage to crops turns out to be significant and estimated to be approximately 43 M€ for the reference year. Production of cotton presents the highest economic loss, which is over 16 M€, followed by table tomato (9 M€), rice (4.2 M€), wheat (4 M€) and oilseed rape (2.8 M€) cultivations. Losses are not spread uniformly among farmers and the major losses occur in areas with valuable ozone-sensitive crops. The results are very useful for highlighting the magnitude of the total economic impacts of photochemical air pollution to the area's agricultural sector and can potentially be used for comparison with studies worldwide. Furthermore, spatial analysis of the economic damage could be of importance for governmental authorities and decision makers since it provides an indicative insight, especially if the economic instruments such as financial incentives or state subsidies to farmers are considered.

  19. Modelled air pollution levels versus EC air quality legislation - results from high resolution simulation.

    PubMed

    Chervenkov, Hristo

    2013-12-01

    An appropriate method for evaluating the air quality of a certain area is to contrast the actual air pollution levels to the critical ones, prescribed in the legislative standards. The application of numerical simulation models for assessing the real air quality status is allowed by the legislation of the European Community (EC). This approach is preferable, especially when the area of interest is relatively big and/or the network of measurement stations is sparse, and the available observational data are scarce, respectively. Such method is very efficient for similar assessment studies due to continuous spatio-temporal coverage of the obtained results. In the study the values of the concentration of the harmful substances sulphur dioxide, (SO2), nitrogen dioxide (NO2), particulate matter - coarse (PM10) and fine (PM2.5) fraction, ozone (O3), carbon monoxide (CO) and ammonia (NH3) in the surface layer obtained from modelling simulations with resolution 10 km on hourly bases are taken to calculate the necessary statistical quantities which are used for comparison with the corresponding critical levels, prescribed in the EC directives. For part of them (PM2.5, CO and NH3) this is done for first time with such resolution. The computational grid covers Bulgaria entirely and some surrounding territories and the calculations are made for every year in the period 1991-2000. The averaged over the whole time slice results can be treated as representative for the air quality situation of the last decade of the former century.

  20. Likelihood of achieving air quality targets under model uncertainties.

    PubMed

    Digar, Antara; Cohan, Daniel S; Cox, Dennis D; Kim, Byeong-Uk; Boylan, James W

    2011-01-01

    Regulatory attainment demonstrations in the United States typically apply a bright-line test to predict whether a control strategy is sufficient to attain an air quality standard. Photochemical models are the best tools available to project future pollutant levels and are a critical part of regulatory attainment demonstrations. However, because photochemical models are uncertain and future meteorology is unknowable, future pollutant levels cannot be predicted perfectly and attainment cannot be guaranteed. This paper introduces a computationally efficient methodology for estimating the likelihood that an emission control strategy will achieve an air quality objective in light of uncertainties in photochemical model input parameters (e.g., uncertain emission and reaction rates, deposition velocities, and boundary conditions). The method incorporates Monte Carlo simulations of a reduced form model representing pollutant-precursor response under parametric uncertainty to probabilistically predict the improvement in air quality due to emission control. The method is applied to recent 8-h ozone attainment modeling for Atlanta, Georgia, to assess the likelihood that additional controls would achieve fixed (well-defined) or flexible (due to meteorological variability and uncertain emission trends) targets of air pollution reduction. The results show that in certain instances ranking of the predicted effectiveness of control strategies may differ between probabilistic and deterministic analyses. PMID:21138291

  1. Likelihood of achieving air quality targets under model uncertainties.

    PubMed

    Digar, Antara; Cohan, Daniel S; Cox, Dennis D; Kim, Byeong-Uk; Boylan, James W

    2011-01-01

    Regulatory attainment demonstrations in the United States typically apply a bright-line test to predict whether a control strategy is sufficient to attain an air quality standard. Photochemical models are the best tools available to project future pollutant levels and are a critical part of regulatory attainment demonstrations. However, because photochemical models are uncertain and future meteorology is unknowable, future pollutant levels cannot be predicted perfectly and attainment cannot be guaranteed. This paper introduces a computationally efficient methodology for estimating the likelihood that an emission control strategy will achieve an air quality objective in light of uncertainties in photochemical model input parameters (e.g., uncertain emission and reaction rates, deposition velocities, and boundary conditions). The method incorporates Monte Carlo simulations of a reduced form model representing pollutant-precursor response under parametric uncertainty to probabilistically predict the improvement in air quality due to emission control. The method is applied to recent 8-h ozone attainment modeling for Atlanta, Georgia, to assess the likelihood that additional controls would achieve fixed (well-defined) or flexible (due to meteorological variability and uncertain emission trends) targets of air pollution reduction. The results show that in certain instances ranking of the predicted effectiveness of control strategies may differ between probabilistic and deterministic analyses.

  2. Functional connectivity based parcellation of the human medial temporal lobe.

    PubMed

    Wang, Shao-Fang; Ritchey, Maureen; Libby, Laura A; Ranganath, Charan

    2016-10-01

    Regional differences in large-scale connectivity have been proposed to underlie functional specialization along the anterior-posterior axis of the medial temporal lobe (MTL), including the hippocampus (HC) and the parahippocampal gyrus (PHG). However, it is unknown whether functional connectivity (FC) can be used reliably to parcellate the human MTL. The current study aimed to differentiate subregions of the HC and the PHG based on patterns of whole-brain intrinsic FC. FC maps were calculated for each slice along the longitudinal axis of the PHG and the HC. A hierarchical clustering algorithm was then applied to these data in order to group slices according to the similarity of their connectivity patterns. Surprisingly, three discrete clusters were identified in the PHG. Two clusters corresponded to the parahippocampal cortex (PHC) and the perirhinal cortex (PRC), and these regions showed preferential connectivity with previously described posterior-medial and anterior-temporal networks, respectively. The third cluster corresponded to an anterior PRC region previously described as area 36d, and this region exhibited preferential connectivity with auditory cortical areas and with a network involved in visceral processing. The three PHG clusters showed different profiles of activation during a memory-encoding task, demonstrating that the FC-based parcellation identified functionally dissociable sub-regions of the PHG. In the hippocampus, no sub-regions were identified via the parcellation procedure. These results indicate that connectivity-based methods can be used to parcellate functional regions within the MTL, and they suggest that studies of memory and high-level cognition need to differentiate between PHC, posterior PRC, and anterior PRC.

  3. Meteorological Processes Affecting Air Quality – Research and Model Development Needs

    EPA Science Inventory

    Meteorology modeling is an important component of air quality modeling systems that defines the physical and dynamical environment for atmospheric chemistry. The meteorology models used for air quality applications are based on numerical weather prediction models that were devel...

  4. European Air Quality and Climate Change: a numerical modeling study

    NASA Astrophysics Data System (ADS)

    Lacressonniere, G.

    2011-12-01

    In the context of climate change, the evolution of air quality in Europe is a challenging scientific question, despite the political measures taken to limit and reduce anthropogenic emissions. Heat waves, changes in transport pathways or synoptic patterns, increase of emissions in other areas in the world, or for instance possible increase of biogenic emissions or changes in deposition and land use may affect adversely future Air Quality levels in Europe. In the context of a project co-funded by the French environment agency ADEME, a numerical modeling study has begun relying on the tools used by Météo-France for its contribution to the 5th IPCC assessment report, to GMES atmospheric services (MACC FP7 project) and to the French national operational Air Quality platform Prév'Air (http://www.prevair.org). In particular, the MOCAGE 3-D chemical transport model (CTM) is used with a configuration comprising a global (2°) and a European domain (0.2°), allowing representation of both long-range transport of pollutants and European Air Quality at relevant resolutions and with a two-ways coupling. MOCAGE includes 47 layers from the surface to 5hPa. The first step of this project was to assess the impact of meteorological forcings, either analyses ("best" meteorology available for the recent past) or climate runs for the current atmosphere, on air quality hindcasts with MOCAGE over Europe. For these climate runs, we rely on Météo-France Earth-System model CNRM-CM, and particularly the ARPEGE-climate general circulation model for the atmosphere. By studying several key variables for Air Quality (surface and low troposphere concentrations of ozone, nitrogen oxides, volatile organic compounds, radicals, PM,...), we investigated the indicators that are robust, through averages over several years, (monthly averages, frequency of exceedances, AOTs, ...) for a given climate when using climatological forcings instead of analyses, which constitutes the reference. Both

  5. Modeling, Monitoring and Fault Diagnosis of Spacecraft Air Contaminants

    NASA Technical Reports Server (NTRS)

    Ramirez, W. Fred; Skliar, Mikhail; Narayan, Anand; Morgenthaler, George W.; Smith, Gerald J.

    1998-01-01

    Control of air contaminants is a crucial factor in the safety considerations of crewed space flight. Indoor air quality needs to be closely monitored during long range missions such as a Mars mission, and also on large complex space structures such as the International Space Station. This work mainly pertains to the detection and simulation of air contaminants in the space station, though much of the work is easily extended to buildings, and issues of ventilation systems. Here we propose a method with which to track the presence of contaminants using an accurate physical model, and also develop a robust procedure that would raise alarms when certain tolerance levels are exceeded. A part of this research concerns the modeling of air flow inside a spacecraft, and the consequent dispersal pattern of contaminants. Our objective is to also monitor the contaminants on-line, so we develop a state estimation procedure that makes use of the measurements from a sensor system and determines an optimal estimate of the contamination in the system as a function of time and space. The real-time optimal estimates in turn are used to detect faults in the system and also offer diagnoses as to their sources. This work is concerned with the monitoring of air contaminants aboard future generation spacecraft and seeks to satisfy NASA's requirements as outlined in their Strategic Plan document (Technology Development Requirements, 1996).

  6. Modeling Airborne Beryllium Concentrations From Open Air Dynamic Testing

    NASA Astrophysics Data System (ADS)

    Becker, N. M.

    2003-12-01

    A heightened awareness of airborne beryllium contamination from industrial activities was reestablished during the late 1980's and early 1990's when it became recognized that Chronic Beryllium Disease (CBD) had not been eradicated, and that the Occupational Health and Safety Administration standards for occupational air exposure to beryllium may not be sufficiently protective. This was in response to the observed CBD increase in multiple industrial settings where beryllium was manufactured and/or machined, thus producing beryllium particulates which are then available for redistribution by airborne transport. Sampling and modeling design activities were expanded at Los Alamos National Laboratory in New Mexico to evaluate potential airborne beryllium exposure to workers who might be exposed during dynamic testing activities associated with nuclear weapons Stockpile Stewardship. Herein is presented the results of multiple types of collected air measurements that were designed to characterize the production and dispersion of beryllium used in components whose performance is evaluated during high explosive detonation at open air firing sites. Data from fallout, high volume air, medium volume air, adhesive film, particle size impactor, and fine-particulate counting techniques will be presented, integrated, and applied in dispersion modeling to assess potential onsite and offsite personal exposures resulting from dynamic testing activities involving beryllium.

  7. Validation of a 3-D hemispheric nested air pollution model

    NASA Astrophysics Data System (ADS)

    Frohn, L. M.; Christensen, J. H.; Brandt, J.; Geels, C.; Hansen, K. M.

    2003-07-01

    Several air pollution transport models have been developed at the National Environmental Research Institute in Denmark over the last decade (DREAM, DEHM, ACDEP and DEOM). A new 3-D nested Eulerian transport-chemistry model: REGIonal high resolutioN Air pollution model (REGINA) is based on modules and parameterisations from these models as well as new methods. The model covers the majority of the Northern Hemisphere with currently one nest implemented. The horizontal resolution in the mother domain is 150 km × 150 km, and the nesting factor is three. A chemical scheme (originally 51 species) has been extended with a detailed description of the ammonia chemistry and implemented in the model. The mesoscale numerical weather prediction model MM5v2 is used as meteorological driver for the model. The concentrations of air pollutants, such as sulphur and nitrogen in various forms, have been calculated, applying zero nesting and one nest. The model setup is currently being validated by comparing calculated values of concentrations to measurements from approximately 100 stations included in the European Monitoring and Evalutation Programme (EMEP). The present paper describes the physical processes and parameterisations of the model together with the modifications of the chemical scheme. Validation of the model calculations by comparison to EMEP measurements for a summer and a winter month is shown and discussed. Furthermore, results from a sensitivity study of the model performance with respect to resolution in emission and meteorology input data is presented. Finally the future prospects of the model are discussed. The overall validation shows that the model performs well with respect to correlation for both monthly and daily mean values.

  8. Scale Issues in Air Quality Modeling Policy Support

    EPA Science Inventory

    This study examines the issues relating to the use of regional photochemical air quality models for evaluating their performance in reproducing the spatio-temporal features embedded in the observations and for designing emission control strategies needed to achieve compliance wit...

  9. AQMEII: A New International Initiative on Air Quality Model Evaluation

    EPA Science Inventory

    We provide a conceptual view of the process of evaluating regional-scale three-dimensional numerical photochemical air quality modeling system, based on an examination of existing approached to the evaluation of such systems as they are currently used in a variety of application....

  10. The analysis of a generic air-to-air missile simulation model

    NASA Technical Reports Server (NTRS)

    Kaplan, Joseph A.; Chappell, Alan R.; Mcmanus, John W.

    1994-01-01

    A generic missile model was developed to evaluate the benefits of using a dynamic missile fly-out simulation system versus a static missile launch envelope system for air-to-air combat simulation. This paper examines the performance of a launch envelope model and a missile fly-out model. The launch envelope model bases its probability of killing the target aircraft on the target aircraft's position at the launch time of the weapon. The benefits gained from a launch envelope model are the simplicity of implementation and the minimal computational overhead required. A missile fly-out model takes into account the physical characteristics of the missile as it simulates the guidance, propulsion, and movement of the missile. The missile's probability of kill is based on the missile miss distance (or the minimum distance between the missile and the target aircraft). The problems associated with this method of modeling are a larger computational overhead, the additional complexity required to determine the missile miss distance, and the additional complexity of determining the reason(s) the missile missed the target. This paper evaluates the two methods and compares the results of running each method on a comprehensive set of test conditions.

  11. InMAP: a new model for air pollution interventions

    NASA Astrophysics Data System (ADS)

    Tessum, C. W.; Hill, J. D.; Marshall, J. D.

    2015-10-01

    Mechanistic air pollution models are essential tools in air quality management. Widespread use of such models is hindered, however, by the extensive expertise or computational resources needed to run most models. Here, we present InMAP (Intervention Model for Air Pollution), which offers an alternative to comprehensive air quality models for estimating the air pollution health impacts of emission reductions and other potential interventions. InMAP estimates annual-average changes in primary and secondary fine particle (PM2.5) concentrations - the air pollution outcome generally causing the largest monetized health damages - attributable to annual changes in precursor emissions. InMAP leverages pre-processed physical and chemical information from the output of a state-of-the-science chemical transport model (WRF-Chem) within an Eulerian modeling framework, to perform simulations that are several orders of magnitude less computationally intensive than comprehensive model simulations. InMAP uses a variable resolution grid that focuses on human exposures by employing higher spatial resolution in urban areas and lower spatial resolution in rural and remote locations and in the upper atmosphere; and by directly calculating steady-state, annual average concentrations. In comparisons run here, InMAP recreates WRF-Chem predictions of changes in total PM2.5 concentrations with population-weighted mean fractional error (MFE) and bias (MFB) < 10 % and population-weighted R2 ~ 0.99. Among individual PM2.5 species, the best predictive performance is for primary PM2.5 (MFE: 16 %; MFB: 13 %) and the worst predictive performance is for particulate nitrate (MFE: 119 %; MFB: 106 %). Potential uses of InMAP include studying exposure, health, and environmental justice impacts of potential shifts in emissions for annual-average PM2.5. Features planned for future model releases include a larger spatial domain, more temporal information, and the ability to predict ground-level ozone (O3

  12. Modeling air pollution in the Tracking and Analysis Framework (TAF)

    SciTech Connect

    Shannon, J.D.

    1998-12-31

    The Tracking and Analysis Framework (TAF) is a set of interactive computer models for integrated assessment of the Acid Rain Provisions (Title IV) of the 1990 Clean Air Act Amendments. TAF is designed to execute in minutes on a personal computer, thereby making it feasible for a researcher or policy analyst to examine quickly the effects of alternate modeling assumptions or policy scenarios. Because the development of TAF involves researchers in many different disciplines, TAF has been given a modular structure. In most cases, the modules contain reduced-form models that are based on more complete models exercised off-line. The structure of TAF as of December 1996 is shown. Both the Atmospheric Pathways Module produce estimates for regional air pollution variables.

  13. Intrinsic functional connectivity pattern-based brain parcellation using normalized cut

    NASA Astrophysics Data System (ADS)

    Cheng, Hewei; Song, Dandan; Wu, Hong; Fan, Yong

    2012-02-01

    In imaging data based brain network analysis, a necessary precursor for constructing meaningful brain networks is to identify functionally homogeneous regions of interest (ROIs) for defining network nodes. For parcellating the brain based on resting state fMRI data, normalized cut is one widely used clustering algorithm which groups voxels according to the similarity of functional signals. Due to low signal to noise ratio (SNR) of resting state fMRI signals, spatial constraint is often applied to functional similarity measures to generate smooth parcellation. However, improper spatial constraint might alter the intrinsic functional connectivity pattern, thus yielding biased parcellation results. To achieve reliable and least biased parcellation of the brain, we propose an optimization method for the spatial constraint to functional similarity measures in normalized cut based brain parcellation. Particularly, we first identify the space of all possible spatial constraints that are able to generate smooth parcellation, then find the spatial constraint that leads to the brain parcellation least biased from the intrinsic function pattern based parcellation, measured by the minimal Ncut value calculated based on the functional similarity measure of original functional signals. The proposed method has been applied to the parcellation of medial superior frontal cortex for 20 subjects based on their resting state fMRI data. The experiment results indicate that our method can generate meaningful parcellation results, consistent with existing functional anatomy knowledge.

  14. Modeling population exposures to outdoor sources of hazardous air pollutants.

    PubMed

    Ozkaynak, Halûk; Palma, Ted; Touma, Jawad S; Thurman, James

    2008-01-01

    Accurate assessment of human exposures is an important part of environmental health effects research. However, most air pollution epidemiology studies rely upon imperfect surrogates of personal exposures, such as information based on available central-site outdoor concentration monitoring or modeling data. In this paper, we examine the limitations of using outdoor concentration predictions instead of modeled personal exposures for over 30 gaseous and particulate hazardous air pollutants (HAPs) in the US. The analysis uses the results from an air quality dispersion model (the ASPEN or Assessment System for Population Exposure Nationwide model) and an inhalation exposure model (the HAPEM or Hazardous Air Pollutant Exposure Model, Version 5), applied by the US. Environmental protection Agency during the 1999 National Air Toxic Assessment (NATA) in the US. Our results show that the total predicted chronic exposure concentrations of outdoor HAPs from all sources are lower than the modeled ambient concentrations by about 20% on average for most gaseous HAPs and by about 60% on average for most particulate HAPs (mainly, due to the exclusion of indoor sources from our modeling analysis and lower infiltration of particles indoors). On the other hand, the HAPEM/ASPEN concentration ratio averages for onroad mobile source exposures were found to be greater than 1 (around 1.20) for most mobile-source related HAPs (e.g. 1, 3-butadiene, acetaldehyde, benzene, formaldehyde) reflecting the importance of near-roadway and commuting environments on personal exposures to HAPs. The distribution of the ratios of personal to ambient concentrations was found to be skewed for a number of the VOCs and reactive HAPs associated with major source emissions, indicating the importance of personal mobility factors. We conclude that the increase in personal exposures from the corresponding predicted ambient levels tends to occur near locations where there are either major emission sources of HAPs

  15. Air pollution dispersion models for human exposure predictions in London.

    PubMed

    Beevers, Sean D; Kitwiroon, Nutthida; Williams, Martin L; Kelly, Frank J; Ross Anderson, H; Carslaw, David C

    2013-01-01

    The London household survey has shown that people travel and are exposed to air pollutants differently. This argues for human exposure to be based upon space-time-activity data and spatio-temporal air quality predictions. For the latter, we have demonstrated the role that dispersion models can play by using two complimentary models, KCLurban, which gives source apportionment information, and Community Multi-scale Air Quality Model (CMAQ)-urban, which predicts hourly air quality. The KCLurban model is in close agreement with observations of NO(X), NO(2) and particulate matter (PM)(10/2.5), having a small normalised mean bias (-6% to 4%) and a large Index of Agreement (0.71-0.88). The temporal trends of NO(X) from the CMAQ-urban model are also in reasonable agreement with observations. Spatially, NO(2) predictions show that within 10's of metres of major roads, concentrations can range from approximately 10-20 p.p.b. up to 70 p.p.b. and that for PM(10/2.5) central London roadside concentrations are approximately double the suburban background concentrations. Exposure to different PM sources is important and we predict that brake wear-related PM(10) concentrations are approximately eight times greater near major roads than at suburban background locations. Temporally, we have shown that average NO(X) concentrations close to roads can range by a factor of approximately six between the early morning minimum and morning rush hour maximum periods. These results present strong arguments for the hybrid exposure model under development at King's and, in future, for in-building models and a model for the London Underground.

  16. Modeling of air pollution from the power plant ash dumps

    NASA Astrophysics Data System (ADS)

    Aleksic, Nenad M.; Balać, Nedeljko

    A simple model of air pollution from power plant ash dumps is presented, with emission rates calculated from the Bagnold formula and transport simulated by the ATDL type model. Moisture effects are accounted for by assumption that there is no pollution on rain days. Annual mean daily sedimentation rates, calculated for the area around the 'Nikola Tesla' power plants near Belgrade for 1987, show reasonably good agreement with observations.

  17. Air-water analogy and the study of hydraulic models

    NASA Technical Reports Server (NTRS)

    Supino, Giulio

    1953-01-01

    The author first sets forth some observations about the theory of models. Then he established certain general criteria for the construction of dynamically similar models in water and in air, through reference to the perfect fluid equations and to the ones pertaining to viscous flow. It is, in addition, pointed out that there are more cases in which the analogy is possible than is commonly supposed.

  18. Bystanders, parcelling, and an absence of trust in the grooming interactions of wild male chimpanzees.

    PubMed

    Kaburu, Stefano S K; Newton-Fisher, Nicholas E

    2016-01-01

    The evolution of cooperation remains a central issue in socio-biology with the fundamental problem of how individuals minimize the risks of being short-changed ('cheated') should their behavioural investment in another not be returned. Economic decisions that individuals make during interactions may depend upon the presence of potential partners nearby, which offers co operators a temptation to defect from the current partner. The parcelling model posits that donors subdivide services into parcels to force cooperation, and that this is contingent on opportunities for defection; that is, the presence of bystanders. Here we test this model and the effect of bystander presence using grooming interactions of wild chimpanzees. We found that with more bystanders, initiators gave less grooming at the beginning of the bout and were more likely to abandon a grooming bout, while bouts were less likely to be reciprocated. We also found that the groomer's initial investment was not higher among frequent groomers or stronger reciprocators, suggesting that contrary to current assumptions, grooming decisions are not based on trust, or bonds, within dyads. Our work highlights the importance of considering immediate social context and the influence of bystanders for understanding the evolution of the behavioural strategies that produce cooperation. PMID:26856371

  19. Bystanders, parcelling, and an absence of trust in the grooming interactions of wild male chimpanzees

    PubMed Central

    Kaburu, Stefano S. K.; Newton-Fisher, Nicholas E.

    2016-01-01

    The evolution of cooperation remains a central issue in socio-biology with the fundamental problem of how individuals minimize the risks of being short-changed (‘cheated’) should their behavioural investment in another not be returned. Economic decisions that individuals make during interactions may depend upon the presence of potential partners nearby, which offers co operators a temptation to defect from the current partner. The parcelling model posits that donors subdivide services into parcels to force cooperation, and that this is contingent on opportunities for defection; that is, the presence of bystanders. Here we test this model and the effect of bystander presence using grooming interactions of wild chimpanzees. We found that with more bystanders, initiators gave less grooming at the beginning of the bout and were more likely to abandon a grooming bout, while bouts were less likely to be reciprocated. We also found that the groomer’s initial investment was not higher among frequent groomers or stronger reciprocators, suggesting that contrary to current assumptions, grooming decisions are not based on trust, or bonds, within dyads. Our work highlights the importance of considering immediate social context and the influence of bystanders for understanding the evolution of the behavioural strategies that produce cooperation. PMID:26856371

  20. Model-based parameterisation of a hydrocyclone air-core

    PubMed

    Podd; Schlaberg; Hoyle

    2000-03-01

    An important metric for the accurate control of a hydrocyclone is the diameter of its air-core. Ultrasonic data from a 16-transducer, 1.5 MHz pulse-echo tomographic system are analysed to determine the variation of the air-core diameter with various operating conditions. The back-projection image reconstruction method is not accurate enough for this task. Sub-millimetre accuracy is obtained, however, by applying a combination of signal processing and model-based reconstruction, using the fact that there is a small variation in the air-core boundary position. The findings correspond well to the results obtained from X-ray and electrical resistance modalities.

  1. MODELS-3 COMMUNITY MULTISCALE AIR QUALITY (CMAQ) MODEL AEROSOL COMPONENT 1: MODEL DESCRIPTION

    EPA Science Inventory

    The aerosol component of the Community Multiscale Air Quality (CMAQ) model is designed to be an efficient and economical depiction of aerosol dynamics in the atmosphere. The approach taken represents the particle size distribution as the superposition of three lognormal subdis...

  2. Urban compaction or dispersion? An air quality modelling study

    NASA Astrophysics Data System (ADS)

    Martins, Helena

    2012-07-01

    Urban sprawl is altering the landscape, with current trends pointing to further changes in land use that will, in turn, lead to changes in population, energy consumption, atmospheric emissions and air quality. Urban planners have debated on the most sustainable urban structure, with arguments in favour and against urban compaction and dispersion. However, it is clear that other areas of expertise have to be involved. Urban air quality and human exposure to atmospheric pollutants as indicators of urban sustainability can contribute to the discussion, namely through the study of the relation between urban structure and air quality. This paper addresses the issue by analysing the impacts of alternative urban growth patterns on the air quality of Porto urban region in Portugal, through a 1-year simulation with the MM5-CAMx modelling system. This region has been experiencing one of the highest European rates of urban sprawl, and at the same time presents a poor air quality. As part of the modelling system setup, a sensitivity study was conducted regarding different land use datasets and spatial distribution of emissions. Two urban development scenarios were defined, SPRAWL and COMPACT, together with their new land use and emission datasets; then meteorological and air quality simulations were performed. Results reveal that SPRAWL land use changes resulted in an average temperature increase of 0.4 °C, with local increases reaching as high as 1.5 °C. SPRAWL results also show an aggravation of PM10 annual average values and an increase in the exceedances to the daily limit value. For ozone, differences between scenarios were smaller, with SPRAWL presenting larger concentration differences than COMPACT. Finally, despite the higher concentrations found in SPRAWL, population exposure to the pollutants is higher for COMPACT because more inhabitants are found in areas of highest concentration levels.

  3. Developing Mental Models about Air Using Inquiry-Based Instruction with Kindergartners

    ERIC Educational Resources Information Center

    Van Hook, Stephen; Huziak, Tracy; Nowak, Katherine

    2005-01-01

    This study examines the development of mental models of air by kindergarten students after completing a series of hands-on, inquiry-based science lessons. The lessons focused on two properties of air: (1) that air takes up space and (2) that it is made of particles ("balls of air"). The students were interviewed about their ideas of air and about…

  4. Impacts of contaminant storage on indoor air quality: Model development

    SciTech Connect

    Sherman, Max H.; Hult, Erin L.

    2013-02-26

    A first-order, lumped capacitance model is used to describe the buffering of airborne chemical species by building materials and furnishings in the indoor environment. The model is applied to describe the interaction between formaldehyde in building materials and the concentration of the species in the indoor air. Storage buffering can decrease the effect of ventilation on the indoor concentration, compared to the inverse dependence of indoor concentration on the air exchange rate that is consistent with a constant emission rate source. If the exposure time of an occupant is long relative to the time scale of depletion of the compound from the storage medium, however, the total exposure will depend inversely on the air exchange rate. This lumped capacitance model is also applied to moisture buffering in the indoor environment, which occurs over much shorter depletion timescales of the order of days. This model provides a framework to interpret the impact of storage buffering on time-varying concentrations of chemical species and resulting occupant exposure. Pseudo-steady state behavior is validated using field measurements. Model behavior over longer times is consistent with formaldehyde and moisture concentration measurements in previous studies.

  5. Impact of High Resolution Land-Use Data in Meteorology and Air Quality Modeling Systems

    EPA Science Inventory

    Accurate land use information is important in meteorology for land surface exchanges, in emission modeling for emission spatial allocation, and in air quality modeling for chemical surface fluxes. Currently, meteorology, emission, and air quality models often use outdated USGS Gl...

  6. Review of Air Exchange Rate Models for Air Pollution Exposure Assessments

    EPA Science Inventory

    A critical aspect of air pollution exposure assessments is estimation of the air exchange rate (AER) for various buildings, where people spend their time. The AER, which is rate the exchange of indoor air with outdoor air, is an important determinant for entry of outdoor air pol...

  7. Aviation System Analysis Capability Air Carrier Investment Model-Cargo

    NASA Technical Reports Server (NTRS)

    Johnson, Jesse; Santmire, Tara

    1999-01-01

    The purpose of the Aviation System Analysis Capability (ASAC) Air Cargo Investment Model-Cargo (ACIMC), is to examine the economic effects of technology investment on the air cargo market, particularly the market for new cargo aircraft. To do so, we have built an econometrically based model designed to operate like the ACIM. Two main drivers account for virtually all of the demand: the growth rate of the Gross Domestic Product (GDP) and changes in the fare yield (which is a proxy of the price charged or fare). These differences arise from a combination of the nature of air cargo demand and the peculiarities of the air cargo market. The net effect of these two factors are that sales of new cargo aircraft are much less sensitive to either increases in GDP or changes in the costs of labor, capital, fuel, materials, and energy associated with the production of new cargo aircraft than the sales of new passenger aircraft. This in conjunction with the relatively small size of the cargo aircraft market means technology improvements to the cargo aircraft will do relatively very little to spur increased sales of new cargo aircraft.

  8. Approaching Expert Results Using a Hierarchical Cerebellum Parcellation Protocol for Multiple Inexpert Human Raters

    PubMed Central

    Bogovic, John A.; Jedynak, Bruno; Rigg, Rachel; Du, Annie; Landman, Bennett A.; Prince, Jerry L.; Ying, Sarah H.

    2012-01-01

    Volumetric measurements obtained from image parcellation have been instrumental in uncovering structure-function relationships. However, anatomical study of the cerebellum is a challenging task. Because of its complex structure, expert human raters have been necessary for reliable and accurate segmentation and parcellation. Such delineations are time-consuming and prohibitively expensive for large studies. Therefore, we present a three-part cerebellar parcellation system that utilizes multiple inexpert human raters that can efficiently and expediently produce results nearly on par with those of experts. This system includes a hierarchical delineation protocol, a rapid verification and evaluation process, and statistical fusion of the inexpert rater parcellations. The quality of the raters’ and fused parcellations was established by examining their Dice similarity coefficient, region of interest (ROI) volumes, and the intraclass correlation coefficient of region volume. The intra-rater ICC was found to be 0.93 at the finest level of parcellation. PMID:22975160

  9. New Methods for Air Quality Model Evaluation with Satellite Data

    NASA Astrophysics Data System (ADS)

    Holloway, T.; Harkey, M.

    2015-12-01

    Despite major advances in the ability of satellites to detect gases and aerosols in the atmosphere, there remains significant, untapped potential to apply space-based data to air quality regulatory applications. Here, we showcase research findings geared toward increasing the relevance of satellite data to support operational air quality management, focused on model evaluation. Particular emphasis is given to nitrogen dioxide (NO2) and formaldehyde (HCHO) from the Ozone Monitoring Instrument aboard the NASA Aura satellite, and evaluation of simulations from the EPA Community Multiscale Air Quality (CMAQ) model. This work is part of the NASA Air Quality Applied Sciences Team (AQAST), and is motivated by ongoing dialog with state and federal air quality management agencies. We present the response of satellite-derived NO2 to meteorological conditions, satellite-derived HCHO:NO2 ratios as an indicator of ozone production regime, and the ability of models to capture these sensitivities over the continental U.S. In the case of NO2-weather sensitivities, we find boundary layer height, wind speed, temperature, and relative humidity to be the most important variables in determining near-surface NO2 variability. CMAQ agreed with relationships observed in satellite data, as well as in ground-based data, over most regions. However, we find that the southwest U.S. is a problem area for CMAQ, where modeled NO2 responses to insolation, boundary layer height, and other variables are at odds with the observations. Our analyses utilize a software developed by our team, the Wisconsin Horizontal Interpolation Program for Satellites (WHIPS): a free, open-source program designed to make satellite-derived air quality data more usable. WHIPS interpolates level 2 satellite retrievals onto a user-defined fixed grid, in effect creating custom-gridded level 3 satellite product. Currently, WHIPS can process the following data products: OMI NO2 (NASA retrieval); OMI NO2 (KNMI retrieval); OMI

  10. Connectivity-based whole brain dual parcellation by group ICA reveals tract structures and decreased connectivity in schizophrenia.

    PubMed

    Wu, Lei; Calhoun, Vince D; Jung, Rex E; Caprihan, Arvind

    2015-11-01

    Mapping brain connectivity based on neuroimaging data is a promising new tool for understanding brain structure and function. In this methods paper, we demonstrate that group independent component analysis (GICA) can be used to perform a dual parcellation of the brain based on its connectivity matrix (cmICA). This dual parcellation consists of a set of spatially independent source maps, and a corresponding set of paired dual maps that define the connectivity of each source map to the brain. These dual maps are called the connectivity profiles of the source maps. Traditional analysis of connectivity matrices has been used previously for brain parcellation, but the present method provides additional information on the connectivity of these segmented regions. In this paper, the whole brain structural connectivity matrices were calculated on a 5 mm(3) voxel scale from diffusion imaging data based on the probabilistic tractography method. The effect of the choice of the number of components (30 and 100) and their stability were examined. This method generated a set of spatially independent components that are consistent with the canonical brain tracts provided by previous anatomic descriptions, with the high order model yielding finer segmentations. The corpus-callosum example shows how this method leads to a robust parcellation of a brain structure based on its connectivity properties. We applied cmICA to study structural connectivity differences between a group of schizophrenia subjects and healthy controls. The connectivity profiles at both model orders showed similar regions with reduced connectivity in schizophrenia patients. These regions included forceps major, right inferior fronto-occipital fasciculus, uncinate fasciculus, thalamic radiation, and corticospinal tract. This paper provides a novel unsupervised data-driven framework that summarizes the information in a large global connectivity matrix and tests for brain connectivity differences. It has the

  11. POPULATION EXPOSURE AND DOSE MODEL FOR AIR TOXICS: A BENZENE CASE STUDY

    EPA Science Inventory

    The EPA's National Exposure Research Laboratory (NERL) is developing a human exposure and dose model called the Stochastic Human Exposure and Dose Simulation model for Air Toxics (SHEDS-AirToxics) to characterize population exposure to air toxics in support of the National Air ...

  12. Mathematical modeling of a primary zinc/air battery

    SciTech Connect

    Mao, Z.; White, R.E. )

    1992-04-01

    This paper reports on the mathematical model developed by Sunu and Bennion that has been extended to include the separator, precipitation of both solid ZnO and K{sub 2}Zn(OH){sub 4}, and the air electrode, and has been used to investigate the behavior of a primary Zn-Air battery with respect to battery design features. Predictions obtained from the model indicate that anode material utilization is predominantly limited by depletion of the concentration of hydroxide ions. The effect of electrode thickness on anode material utilization is insignificant, whereas material loading per unit volume has a great effect on anode material utilization; a higher loading lowers both the anode material utilization and delivered capacity. Use of a thick separator will increase the anode material utilization, but may reduce the cell voltage.

  13. Mathematical modeling of a primary zinc/air battery

    NASA Astrophysics Data System (ADS)

    Mao, Z.; White, R. E.

    1992-04-01

    The mathematical model developed by Sunu and Bennion has been extended to include the separator, precipitation of both solid ZnO and K2Zn(OH)4, and the air electrode, and has been used to investigate the behavior of a primary Zn-Air battery with respect to battery design features. Predictions obtained from the model indicate that anode material utilization is predominantly limited by depletion of the concentration of hydroxide ions. The effect of electrode thickness on anode material utilization is insignificant, whereas material loading per unit volume has a great effect on anode material utilization; a higher loading lowers both the anode material utilization and delivered capacity. Use of a thick separator will increase the anode material utilization, but may reduce the cell voltage.

  14. Mathematical modeling of a primary zinc/air battery

    NASA Technical Reports Server (NTRS)

    Mao, Z.; White, R. E.

    1992-01-01

    The mathematical model developed by Sunu and Bennion has been extended to include the separator, precipitation of both solid ZnO and K2Zn(OH)4, and the air electrode, and has been used to investigate the behavior of a primary Zn-Air battery with respect to battery design features. Predictions obtained from the model indicate that anode material utilization is predominantly limited by depletion of the concentration of hydroxide ions. The effect of electrode thickness on anode material utilization is insignificant, whereas material loading per unit volume has a great effect on anode material utilization; a higher loading lowers both the anode material utilization and delivered capacity. Use of a thick separator will increase the anode material utilization, but may reduce the cell voltage.

  15. Co-activation based parcellation of the human frontal pole.

    PubMed

    Ray, K L; Zald, D H; Bludau, S; Riedel, M C; Bzdok, D; Yanes, J; Falcone, K E; Amunts, K; Fox, P T; Eickhoff, S B; Laird, A R

    2015-12-01

    Historically, the human frontal pole (FP) has been considered as a single architectonic area. Brodmann's area 10 is located in the frontal lobe with known contributions in the execution of various higher order cognitive processes. However, recent cytoarchitectural studies of the FP in humans have shown that this portion of cortex contains two distinct cytoarchitectonic regions. Since architectonic differences are accompanied by differential connectivity and functions, the frontal pole qualifies as a candidate region for exploratory parcellation into functionally discrete sub-regions. We investigated whether this functional heterogeneity is reflected in distinct segregations within cytoarchitectonically defined FP-areas using meta-analytic co-activation based parcellation (CBP). The CBP method examined the co-activation patterns of all voxels within the FP as reported in functional neuroimaging studies archived in the BrainMap database. Voxels within the FP were subsequently clustered into sub-regions based on the similarity of their respective meta-analytically derived co-activation maps. Performing this CBP analysis on the FP via k-means clustering produced a distinct 3-cluster parcellation for each hemisphere corresponding to previously identified cytoarchitectural differences. Post-hoc functional characterization of clusters via BrainMap metadata revealed that lateral regions of the FP mapped to memory and emotion domains, while the dorso- and ventromedial clusters were associated broadly with emotion and social cognition processes. Furthermore, the dorsomedial regions contain an emphasis on theory of mind and affective related paradigms whereas ventromedial regions couple with reward tasks. Results from this study support previous segregations of the FP and provide meta-analytic contributions to the ongoing discussion of elucidating functional architecture within human FP. PMID:26254112

  16. Comparison of stationary and personal air sampling with an air dispersion model for children's ambient exposure to manganese.

    PubMed

    Fulk, Florence; Haynes, Erin N; Hilbert, Timothy J; Brown, David; Petersen, Dan; Reponen, Tiina

    2016-09-01

    Manganese (Mn) is ubiquitous in the environment and essential for normal growth and development, yet excessive exposure can lead to impairments in neurological function. This study modeled ambient Mn concentrations as an alternative to stationary and personal air sampling to assess exposure for children enrolled in the Communities Actively Researching Exposure Study in Marietta, OH. Ambient air Mn concentration values were modeled using US Environmental Protection Agency's Air Dispersion Model AERMOD based on emissions from the ferromanganese refinery located in Marietta. Modeled Mn concentrations were compared with Mn concentrations from a nearby stationary air monitor. The Index of Agreement for modeled versus monitored data was 0.34 (48 h levels) and 0.79 (monthly levels). Fractional bias was 0.026 for 48 h levels and -0.019 for monthly levels. The ratio of modeled ambient air Mn to measured ambient air Mn at the annual time scale was 0.94. Modeled values were also time matched to personal air samples for 19 children. The modeled values explained a greater degree of variability in personal exposures compared with time-weighted distance from the emission source. Based on these results modeled Mn concentrations provided a suitable approach for assessing airborne Mn exposure in this cohort. PMID:27168393

  17. Comparison of stationary and personal air sampling with an air dispersion model for children's ambient exposure to manganese.

    PubMed

    Fulk, Florence; Haynes, Erin N; Hilbert, Timothy J; Brown, David; Petersen, Dan; Reponen, Tiina

    2016-09-01

    Manganese (Mn) is ubiquitous in the environment and essential for normal growth and development, yet excessive exposure can lead to impairments in neurological function. This study modeled ambient Mn concentrations as an alternative to stationary and personal air sampling to assess exposure for children enrolled in the Communities Actively Researching Exposure Study in Marietta, OH. Ambient air Mn concentration values were modeled using US Environmental Protection Agency's Air Dispersion Model AERMOD based on emissions from the ferromanganese refinery located in Marietta. Modeled Mn concentrations were compared with Mn concentrations from a nearby stationary air monitor. The Index of Agreement for modeled versus monitored data was 0.34 (48 h levels) and 0.79 (monthly levels). Fractional bias was 0.026 for 48 h levels and -0.019 for monthly levels. The ratio of modeled ambient air Mn to measured ambient air Mn at the annual time scale was 0.94. Modeled values were also time matched to personal air samples for 19 children. The modeled values explained a greater degree of variability in personal exposures compared with time-weighted distance from the emission source. Based on these results modeled Mn concentrations provided a suitable approach for assessing airborne Mn exposure in this cohort.

  18. Using natural beta emission for detecting concealed tobacco in parcels

    NASA Astrophysics Data System (ADS)

    Myers, Jeremy; Hussein, Esam M. A.

    2007-10-01

    It is suspected that postal systems are used for the illegal shipment of tobacco products to circumvent taxation and excise payments. This paper demonstrates that beta-particle emission from the potassium-40 contained in tobacco can be used to passively detect its presence in paperboard postal parcels. The same concept can be utilized for the detection of marijuana, whose leaves are also rich in 40K. The combination of high beta activity and a low weight is a good indicator of the presence of these two contraband materials.

  19. Oblique along path toward structures at rear of parcel. Original ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    Oblique along path toward structures at rear of parcel. Original skinny mosaic path along edge of structures was altered (delineation can be seen in concrete) path was widened with a newer mosaic to make access to the site safer. Structures (from right) edge of Round House (with "Spring Garden"), Pencil house, Shell House, School House, wood lattice is attached to chain-link fence along north (rear) property line. These structures were all damaged by the 1994 Northridge earthquake. Camera facing northeast. - Grandma Prisbrey's Bottle Village, 4595 Cochran Street, Simi Valley, Ventura County, CA

  20. Space-Time Fusion Under Error in Computer Model Output: An Application to Modeling Air Quality

    EPA Science Inventory

    In the last two decades a considerable amount of research effort has been devoted to modeling air quality with public health objectives. These objectives include regulatory activities such as setting standards along with assessing the relationship between exposure to air pollutan...

  1. Simulation model finned water-air-coil withoutcondensation

    SciTech Connect

    Wetter, Michael

    1999-01-01

    A simple simulation model of a finned water-to- air coil without condensation is presented. The model belongs to a collection of simulation models that allows eficient computer simulation of heating, ventilation, and air-conditioning (HVAC) systems. The main emphasis of the models is short computation time and use of input data that are known in the design process of an HVAC system. The target of the models is to describe the behavior of HVAC components in the part load operation mode, which is becoming increasingly important for energy efficient HVAC systems. The models are intended to be used for yearly energy calculation or load calculation with time steps of about 10 minutes or larger. Short-time dynamic effects, which are of interest for different aspects of control performance, are neglected. The part load behavior of the coil is expressed in terms of the nominal condition and the dimensionless variation of the heat transfer with change of mass flow and temperature on the water side and the air side. The effectiveness- NTU relations are used to parametrize the convective heat transfer at nominal conditions and to compute the part load conditions. Geometrical data for the coil are not required, The calculation of the convective heat transfer coefficients at nominal conditions is based on the ratio of the air side heat transfer coefficients multiplied by the fin eficiency and divided by the water side heat transfer coefficient. In this approach, the only geometrical information required are the cross section areas, which are needed to calculate the~uid velocities. The formulas for estimating this ratio are presented. For simplicity the model ignores condensation. The model is static and uses only explicit equations. The explicit formulation ensures short computation time and numerical stability. This allows using the model with sophisticated engineering methods such as automatic system optimization. The paper fully outlines the algorithm description and its

  2. The air quality forecast in Beijing with Community Multi-scale Air Quality Modeling (CMAQ) System: model evaluation and improvement

    NASA Astrophysics Data System (ADS)

    Wu, Q.

    2013-12-01

    The MM5-SMOKE-CMAQ model system, which is developed by the United States Environmental Protection Agency(U.S. EPA) as the Models-3 system, has been used for the daily air quality forecast in the Beijing Municipal Environmental Monitoring Center(Beijing MEMC), as a part of the Ensemble Air Quality Forecast System for Beijing(EMS-Beijing) since the Olympic Games year 2008. In this study, we collect the daily forecast results of the CMAQ model in the whole year 2010 for the model evaluation. The results show that the model play a good model performance in most days but underestimate obviously in some air pollution episode. A typical air pollution episode from 11st - 20th January 2010 was chosen, which the air pollution index(API) of particulate matter (PM10) observed by Beijing MEMC reaches to 180 while the prediction of PM10-API is about 100. Taking in account all stations in Beijing, including urban and suburban stations, three numerical methods are used for model improvement: firstly, enhance the inner domain with 4km grids, the coverage from only Beijing to the area including its surrounding cities; secondly, update the Beijing stationary area emission inventory, from statistical county-level to village-town level, that would provide more detail spatial informance for area emissions; thirdly, add some industrial points emission in Beijing's surrounding cities, the latter two are both the improvement of emission. As the result, the peak of the nine national standard stations averaged PM10-API, which is simulated by CMAQ as daily hindcast PM10-API, reach to 160 and much near to the observation. The new results show better model performance, which the correlation coefficent is 0.93 in national standard stations average and 0.84 in all stations, the relative error is 15.7% in national standard stations averaged and 27% in all stations. The time series of 9 national standard in Beijing urban The scatter diagram of all stations in Beijing, the red is the forecast and

  3. Long-range transport modeling of air pollution episodes.

    PubMed

    de Leeuw, F A; Leyssius, H J

    1989-02-01

    The air quality network in the Netherlands is based on a regular grid with an interstation distance of 30 to 40 km. In or close to source areas, a higher station density is realized. Atmospheric transport models form an intrinsic part of the air quality monitoring system. The models are constructed in such a way that only routinely available meteorological input data are needed. The models are applied for interpretation and generalization of the measurements in terms of contributions of source categories. In scenario studies, the potential effect of abatement strategies is explored. The output of the models consists of concentration and deposition fields of NOx, NO2, SO2, sulfate, and nitrate on the scale of the Netherlands or on the scale of northwestern Europe. In the present version the models are not directly suitable to estimate exposures to acidic aerosols; however, in combination with limited aerosol measurements, the model predictions can be used to provide information on the spatial and temporal distribution of acidic aerosols as needed for exposure assessment.

  4. Transboundary air pollution in Asia: Model development and policy implications

    NASA Astrophysics Data System (ADS)

    Holloway, Tracey

    2001-12-01

    This work investigates transboundary air pollution in Asia through atmospheric modeling and public policy analysis. As an example of models actively shaping environmental policy, the Convention on Long-Range Transboundary Air Pollution in Europe (LRTAP) is selected as a case study. The LRTAP Convention is the only mulit- lateral air pollution agreement to date, and results from the RAINS integrated assessment model were heavily used to calculate nationally differentiated emission ceilings. Atmospheric chemistry and transport are included in RAINS through the use of transfer coefficients (or ``source-receptor relationships'') relating pollutant transfer among European nations. Following past work with ATMOS to simulate sulfur species in Asia, here ATMOS is developed to include odd-nitrogen. Fitting with the linear structure of ATMOS and the emphasis on computational efficiency, a simplified chemical scheme developed for use in the NOAA Geophysical Fluid Dynamics Laboratory Global Chemical Transport Model (GFDL GCTM) is adopted. The method solves for the interconversions between NOx, HNO3, and PAN based on five reaction rates stored in look-up tables. ATMOS is used to calculate source-receptor relationships for Asia. Significant exchange of NOy occurs among China, North and South Korea, and Japan. On an annual average basis, China contributes 18% to Japan's total nitrate deposition, 46% to North Korea, and 26% to South Korea. Nitrate deposition is an important component of acidification (along with sulfate deposition), contributing 30-50% to the acid burden over most of Japan, and more than 50% to acid deposition in southeast Asia, where biomass burning emits high levels of NOx. In evaluating the policy-relevance of results from the ATMOS model, four factors are taken into account: the uncertainty and limitations of ATMOS, the environmental concerns facing Asia, the current status of the scientific community in relation to regional air pollution in the region, and

  5. Time-based collision risk modeling for air traffic management

    NASA Astrophysics Data System (ADS)

    Bell, Alan E.

    Since the emergence of commercial aviation in the early part of last century, economic forces have driven a steadily increasing demand for air transportation. Increasing density of aircraft operating in a finite volume of airspace is accompanied by a corresponding increase in the risk of collision, and in response to a growing number of incidents and accidents involving collisions between aircraft, governments worldwide have developed air traffic control systems and procedures to mitigate this risk. The objective of any collision risk management system is to project conflicts and provide operators with sufficient opportunity to recognize potential collisions and take necessary actions to avoid them. It is therefore the assertion of this research that the currency of collision risk management is time. Future Air Traffic Management Systems are being designed around the foundational principle of four dimensional trajectory based operations, a method that replaces legacy first-come, first-served sequencing priorities with time-based reservations throughout the airspace system. This research will demonstrate that if aircraft are to be sequenced in four dimensions, they must also be separated in four dimensions. In order to separate aircraft in four dimensions, time must emerge as the primary tool by which air traffic is managed. A functional relationship exists between the time-based performance of aircraft, the interval between aircraft scheduled to cross some three dimensional point in space, and the risk of collision. This research models that relationship and presents two key findings. First, a method is developed by which the ability of an aircraft to meet a required time of arrival may be expressed as a robust standard for both industry and operations. Second, a method by which airspace system capacity may be increased while maintaining an acceptable level of collision risk is presented and demonstrated for the purpose of formulating recommendations for procedures

  6. Methodology for Modeling the Microbial Contamination of Air Filters

    PubMed Central

    Joe, Yun Haeng; Yoon, Ki Young; Hwang, Jungho

    2014-01-01

    In this paper, we propose a theoretical model to simulate microbial growth on contaminated air filters and entrainment of bioaerosols from the filters to an indoor environment. Air filter filtration and antimicrobial efficiencies, and effects of dust particles on these efficiencies, were evaluated. The number of bioaerosols downstream of the filter could be characterized according to three phases: initial, transitional, and stationary. In the initial phase, the number was determined by filtration efficiency, the concentration of dust particles entering the filter, and the flow rate. During the transitional phase, the number of bioaerosols gradually increased up to the stationary phase, at which point no further increase was observed. The antimicrobial efficiency and flow rate were the dominant parameters affecting the number of bioaerosols downstream of the filter in the transitional and stationary phase, respectively. It was found that the nutrient fraction of dust particles entering the filter caused a significant change in the number of bioaerosols in both the transitional and stationary phases. The proposed model would be a solution for predicting the air filter life cycle in terms of microbiological activity by simulating the microbial contamination of the filter. PMID:24523908

  7. Updraft Model for Development of Autonomous Soaring Uninhabited Air Vehicles

    NASA Technical Reports Server (NTRS)

    Allen, Michael J.

    2006-01-01

    Large birds and glider pilots commonly use updrafts caused by convection in the lower atmosphere to extend flight duration, increase cross-country speed, improve range, or simply to conserve energy. Uninhabited air vehicles may also have the ability to exploit updrafts to improve performance. An updraft model was developed at NASA Dryden Flight Research Center (Edwards, California) to investigate the use of convective lift for uninhabited air vehicles in desert regions. Balloon and surface measurements obtained at the National Oceanic and Atmospheric Administration Surface Radiation station (Desert Rock, Nevada) enabled the model development. The data were used to create a statistical representation of the convective velocity scale, w*, and the convective mixing-layer thickness, zi. These parameters were then used to determine updraft size, vertical velocity profile, spacing, and maximum height. This paper gives a complete description of the updraft model and its derivation. Computer code for running the model is also given in conjunction with a check case for model verification.

  8. Cerebellar Functional Parcellation Using Sparse Dictionary Learning Clustering.

    PubMed

    Wang, Changqing; Kipping, Judy; Bao, Chenglong; Ji, Hui; Qiu, Anqi

    2016-01-01

    The human cerebellum has recently been discovered to contribute to cognition and emotion beyond the planning and execution of movement, suggesting its functional heterogeneity. We aimed to identify the functional parcellation of the cerebellum using information from resting-state functional magnetic resonance imaging (rs-fMRI). For this, we introduced a new data-driven decomposition-based functional parcellation algorithm, called Sparse Dictionary Learning Clustering (SDLC). SDLC integrates dictionary learning, sparse representation of rs-fMRI, and k-means clustering into one optimization problem. The dictionary is comprised of an over-complete set of time course signals, with which a sparse representation of rs-fMRI signals can be constructed. Cerebellar functional regions were then identified using k-means clustering based on the sparse representation of rs-fMRI signals. We solved SDLC using a multi-block hybrid proximal alternating method that guarantees strong convergence. We evaluated the reliability of SDLC and benchmarked its classification accuracy against other clustering techniques using simulated data. We then demonstrated that SDLC can identify biologically reasonable functional regions of the cerebellum as estimated by their cerebello-cortical functional connectivity. We further provided new insights into the cerebello-cortical functional organization in children.

  9. Cerebellar Functional Parcellation Using Sparse Dictionary Learning Clustering

    PubMed Central

    Wang, Changqing; Kipping, Judy; Bao, Chenglong; Ji, Hui; Qiu, Anqi

    2016-01-01

    The human cerebellum has recently been discovered to contribute to cognition and emotion beyond the planning and execution of movement, suggesting its functional heterogeneity. We aimed to identify the functional parcellation of the cerebellum using information from resting-state functional magnetic resonance imaging (rs-fMRI). For this, we introduced a new data-driven decomposition-based functional parcellation algorithm, called Sparse Dictionary Learning Clustering (SDLC). SDLC integrates dictionary learning, sparse representation of rs-fMRI, and k-means clustering into one optimization problem. The dictionary is comprised of an over-complete set of time course signals, with which a sparse representation of rs-fMRI signals can be constructed. Cerebellar functional regions were then identified using k-means clustering based on the sparse representation of rs-fMRI signals. We solved SDLC using a multi-block hybrid proximal alternating method that guarantees strong convergence. We evaluated the reliability of SDLC and benchmarked its classification accuracy against other clustering techniques using simulated data. We then demonstrated that SDLC can identify biologically reasonable functional regions of the cerebellum as estimated by their cerebello-cortical functional connectivity. We further provided new insights into the cerebello-cortical functional organization in children. PMID:27199650

  10. Estimating Lightning NOx Emissions for Regional Air Quality Modeling

    NASA Astrophysics Data System (ADS)

    Holloway, T.; Scotty, E.; Harkey, M.

    2014-12-01

    Lightning emissions have long been recognized as an important source of nitrogen oxides (NOx) on a global scale, and an essential emission component for global atmospheric chemistry models. However, only in recent years have regional air quality models incorporated lightning NOx emissions into simulations. The growth in regional modeling of lightning emissions has been driven in part by comparisons with satellite-derived estimates of column NO2, especially from the Ozone Monitoring Instrument (OMI) aboard the Aura satellite. We present and evaluate a lightning inventory for the EPA Community Multiscale Air Quality (CMAQ) model. Our approach follows Koo et al. [2010] in the approach to spatially and temporally allocating a given total value based on cloud-top height and convective precipitation. However, we consider alternate total NOx emission values (which translate into alternate lightning emission factors) based on a review of the literature and performance evaluation against OMI NO2 for July 2007 conditions over the U.S. and parts of Canada and Mexico. The vertical distribution of lightning emissions follow a bimodal distribution from Allen et al. [2012] calculated over 27 vertical model layers. Total lightning NO emissions for July 2007 show the highest above-land emissions in Florida, southeastern Texas and southern Louisiana. Although agreement with OMI NO2 across the domain varied significantly depending on lightning NOx assumptions, agreement among the simulations at ground-based NO2 monitors from the EPA Air Quality System database showed no meaningful sensitivity to lightning NOx. Emissions are compared with prior studies, which find similar distribution patterns, but a wide range of calculated magnitudes.

  11. ONE ATMOSPHERE MODELING FOR AIR QUALITY: BUILDING PARTNERSHIPS THAT TRANSITION RESEARCH INTO APPLICATIONS

    EPA Science Inventory

    The Community Miultiscale Air Quality (CMAQ) modeling system is a "one atmosphere" chemical transport model that simulates the transport and fate of air pollutants from urban to continental scales and from daily to annual time intervals.

  12. ADDRESSING HUMAN EXPOSURES TO AIR POLLUTANTS AROUND BUILDINGS IN URBAN AREAS WITH COMPUTATIONAL FLUID DYNAMICS MODELS

    EPA Science Inventory

    This paper discusses the status and application of Computational Fluid Dynamics (CFD) models to address challenges for modeling human exposures to air pollutants around urban building microenvironments. There are challenges for more detailed understanding of air pollutant sour...

  13. Off-site air monitoring following methyl bromide chamber and building fumigations and evaluation of the ISCST air dispersion model

    SciTech Connect

    Barry, T.; Swgawa, R.; Wofford, P.

    1995-12-31

    The Department of Pesticide Regulation`s preliminary risk characterization of methyl bromide indicated an inadequate margin of safety for several exposure scenarios. Characterization of the air concentrations associated with common methyl bromide use patterns was necessary to determine specific scenarios that result in an unacceptable margin of safety. Field monitoring data were used in conjunction with the Industrial Source Complex, Short Tenn (ISCST) air dispersion model to characterize air concentrations associated with various types of methyl bromide applications. Chamber and building fumigations were monitored and modelled. For each fumigation the emission rates, chamber or building specifications and on-site meteorological data were input into the ISCST model. The model predicted concentrations were compared to measured air concentrations. The concentrations predicted by the ISCST model reflect both the pattern and magnitude of the measured concentrations. Required buffer zones were calculated using the ISCST output.

  14. A simple model for calculating air pollution within street canyons

    NASA Astrophysics Data System (ADS)

    Venegas, Laura E.; Mazzeo, Nicolás A.; Dezzutti, Mariana C.

    2014-04-01

    This paper introduces the Semi-Empirical Urban Street (SEUS) model. SEUS is a simple mathematical model based on the scaling of air pollution concentration inside street canyons employing the emission rate, the width of the canyon, the dispersive velocity scale and the background concentration. Dispersive velocity scale depends on turbulent motions related to wind and traffic. The parameterisations of these turbulent motions include two dimensionless empirical parameters. Functional forms of these parameters have been obtained from full scale data measured in street canyons at four European cities. The sensitivity of SEUS model is studied analytically. Results show that relative errors in the evaluation of the two dimensionless empirical parameters have less influence on model uncertainties than uncertainties in other input variables. The model estimates NO2 concentrations using a simple photochemistry scheme. SEUS is applied to estimate NOx and NO2 hourly concentrations in an irregular and busy street canyon in the city of Buenos Aires. The statistical evaluation of results shows that there is a good agreement between estimated and observed hourly concentrations (e.g. fractional bias are -10.3% for NOx and +7.8% for NO2). The agreement between the estimated and observed values has also been analysed in terms of its dependence on wind speed and direction. The model shows a better performance for wind speeds >2 m s-1 than for lower wind speeds and for leeward situations than for others. No significant discrepancies have been found between the results of the proposed model and that of a widely used operational dispersion model (OSPM), both using the same input information.

  15. Modelling of dynamic targeting in the Air Operations Centre

    NASA Astrophysics Data System (ADS)

    Lo, Edward H. S.; Au, T. Andrew

    2007-12-01

    Air Operations Centres (AOCs) are high stress multitask environments for planning and executing of theatre-wide airpower. Operators have multiple responsibilities to ensure that the orchestration of air assets is coordinated to maximum effect. AOCs utilise a dynamic targeting process to immediately prosecute time-sensitive targets. For this process to work effectively, a timely decision must be made regarding the appropriate course of action before the action is enabled. A targeting solution is typically developed using a number of inter-related processes in the kill chain - the Find, Fix, Track, Target, Engage, and Assess (F2T2EA) model. The success of making a right decision about dynamic targeting is ultimately limited by the cognitive and cooperative skills of the team prosecuting the mission and their associated workload. This paper presents a model of human interaction and tasks within the dynamic targeting sequence. The complex network of tasks executed by the team can be analysed by undertaking simulation of the model to identify possible information-processing bottlenecks and overloads. The model was subjected to various tests to generate typical outcomes, operator utilisation, duration as well as rates of output in the dynamic targeting process. This capability will allow for future "what-if" evaluations of numerous concepts for team formation or task reallocation, complementing live exercises and experiments.

  16. Urban scale air quality modelling using detailed traffic emissions estimates

    NASA Astrophysics Data System (ADS)

    Borrego, C.; Amorim, J. H.; Tchepel, O.; Dias, D.; Rafael, S.; Sá, E.; Pimentel, C.; Fontes, T.; Fernandes, P.; Pereira, S. R.; Bandeira, J. M.; Coelho, M. C.

    2016-04-01

    The atmospheric dispersion of NOx and PM10 was simulated with a second generation Gaussian model over a medium-size south-European city. Microscopic traffic models calibrated with GPS data were used to derive typical driving cycles for each road link, while instantaneous emissions were estimated applying a combined Vehicle Specific Power/Co-operative Programme for Monitoring and Evaluation of the Long-range Transmission of Air Pollutants in Europe (VSP/EMEP) methodology. Site-specific background concentrations were estimated using time series analysis and a low-pass filter applied to local observations. Air quality modelling results are compared against measurements at two locations for a 1 week period. 78% of the results are within a factor of two of the observations for 1-h average concentrations, increasing to 94% for daily averages. Correlation significantly improves when background is added, with an average of 0.89 for the 24 h record. The results highlight the potential of detailed traffic and instantaneous exhaust emissions estimates, together with filtered urban background, to provide accurate input data to Gaussian models applied at the urban scale.

  17. A statistical model for characterizing common air pollutants in air-conditioned offices

    NASA Astrophysics Data System (ADS)

    Wong, L. T.; Mui, K. W.; Hui, P. S.

    Maintaining acceptable indoor air quality (IAQ) for a healthy environment is of primary concern, policymakers have developed different strategies to address the performance of it based on proper assessment methodologies and monitoring plans. It could be cost prohibitive to sample all toxic pollutants in a building. In search of a more manageable number of parameters for cost-effective IAQ assessment, this study investigated the probable correlations among the 12 indoor environmental parameters listed in the IAQ certification scheme of the Hong Kong Environment Protection Department (HKEPD) in 422 Hong Kong offices. These 12 parameters consists of nine indoor air pollutants: carbon dioxide (CO 2), carbon monoxide (CO), respirable suspended particulates (RSP), nitrogen dioxide (NO 2), ozone (O 3), formaldehyde (HCHO), total volatile organic compounds (TVOC), radon (Rn), airborne bacteria count (ABC); and three thermal comfort parameters: temperature ( T), relative humidity (RH) and air velocity ( V). The relative importance of the correlations derived, from largest to smallest loadings, was ABC, Rn, CO, RH, RSP, CO 2, TVOC, O 3, T, V, NO 2 and HCHO. Together with the mathematical expressions derived, an alternative sampling protocol for IAQ assessment with the three 'most representative and independent' parameters namely RSP, CO 2 and TVOC measured in an office environment was proposed. The model validity was verified with on site measurements from 43 other offices in Hong Kong. The measured CO 2, RSP and TVOC concentrations were used to predict the probable levels of the other nine parameters and good agreement was found between the predictions and measurements. This simplified protocol provides an easy tool for performing IAQ monitoring in workplaces and will be useful for determining appropriate mitigation measures to finally honor the certification scheme in a cost-effective way.

  18. Evaluation of the Community Multiscale Air Quality model version 5.1

    EPA Science Inventory

    The Community Multiscale Air Quality model is a state-of-the-science air quality model that simulates the emission, transport and fate of numerous air pollutants, including ozone and particulate matter. The Atmospheric Modeling and Analysis Division (AMAD) of the U.S. Environment...

  19. A review and evaluation of intraurban air pollution exposure models.

    PubMed

    Jerrett, Michael; Arain, Altaf; Kanaroglou, Pavlos; Beckerman, Bernardo; Potoglou, Dimitri; Sahsuvaroglu, Talar; Morrison, Jason; Giovis, Chris

    2005-03-01

    The development of models to assess air pollution exposures within cities for assignment to subjects in health studies has been identified as a priority area for future research. This paper reviews models for assessing intraurban exposure under six classes, including: (i) proximity-based assessments, (ii) statistical interpolation, (iii) land use regression models, (iv) line dispersion models, (v) integrated emission-meteorological models, and (vi) hybrid models combining personal or household exposure monitoring with one of the preceding methods. We enrich this review of the modelling procedures and results with applied examples from Hamilton, Canada. In addition, we qualitatively evaluate the models based on key criteria important to health effects assessment research. Hybrid models appear well suited to overcoming the problem of achieving population representative samples while understanding the role of exposure variation at the individual level. Remote sensing and activity-space analysis will complement refinements in pre-existing methods, and with expected advances, the field of exposure assessment may help to reduce scientific uncertainties that now impede policy intervention aimed at protecting public health.

  20. Prediction of Indoor Air Exposure from Outdoor Air Quality Using an Artificial Neural Network Model for Inner City Commercial Buildings.

    PubMed

    Challoner, Avril; Pilla, Francesco; Gill, Laurence

    2015-12-01

    NO₂ and particulate matter are the air pollutants of most concern in Ireland, with possible links to the higher respiratory and cardiovascular mortality and morbidity rates found in the country compared to the rest of Europe. Currently, air quality limits in Europe only cover outdoor environments yet the quality of indoor air is an essential determinant of a person's well-being, especially since the average person spends more than 90% of their time indoors. The modelling conducted in this research aims to provide a framework for epidemiological studies by the use of publically available data from fixed outdoor monitoring stations to predict indoor air quality more accurately. Predictions are made using two modelling techniques, the Personal-exposure Activity Location Model (PALM), to predict outdoor air quality at a particular building, and Artificial Neural Networks, to model the indoor/outdoor relationship of the building. This joint approach has been used to predict indoor air concentrations for three inner city commercial buildings in Dublin, where parallel indoor and outdoor diurnal monitoring had been carried out on site. This modelling methodology has been shown to provide reasonable predictions of average NO₂ indoor air quality compared to the monitored data, but did not perform well in the prediction of indoor PM2.5 concentrations. Hence, this approach could be used to determine NO₂ exposures more rigorously of those who work and/or live in the city centre, which can then be linked to potential health impacts.

  1. Prediction of Indoor Air Exposure from Outdoor Air Quality Using an Artificial Neural Network Model for Inner City Commercial Buildings

    PubMed Central

    Challoner, Avril; Pilla, Francesco; Gill, Laurence

    2015-01-01

    NO2 and particulate matter are the air pollutants of most concern in Ireland, with possible links to the higher respiratory and cardiovascular mortality and morbidity rates found in the country compared to the rest of Europe. Currently, air quality limits in Europe only cover outdoor environments yet the quality of indoor air is an essential determinant of a person’s well-being, especially since the average person spends more than 90% of their time indoors. The modelling conducted in this research aims to provide a framework for epidemiological studies by the use of publically available data from fixed outdoor monitoring stations to predict indoor air quality more accurately. Predictions are made using two modelling techniques, the Personal-exposure Activity Location Model (PALM), to predict outdoor air quality at a particular building, and Artificial Neural Networks, to model the indoor/outdoor relationship of the building. This joint approach has been used to predict indoor air concentrations for three inner city commercial buildings in Dublin, where parallel indoor and outdoor diurnal monitoring had been carried out on site. This modelling methodology has been shown to provide reasonable predictions of average NO2 indoor air quality compared to the monitored data, but did not perform well in the prediction of indoor PM2.5 concentrations. Hence, this approach could be used to determine NO2 exposures more rigorously of those who work and/or live in the city centre, which can then be linked to potential health impacts. PMID:26633448

  2. Prediction of Indoor Air Exposure from Outdoor Air Quality Using an Artificial Neural Network Model for Inner City Commercial Buildings.

    PubMed

    Challoner, Avril; Pilla, Francesco; Gill, Laurence

    2015-12-01

    NO₂ and particulate matter are the air pollutants of most concern in Ireland, with possible links to the higher respiratory and cardiovascular mortality and morbidity rates found in the country compared to the rest of Europe. Currently, air quality limits in Europe only cover outdoor environments yet the quality of indoor air is an essential determinant of a person's well-being, especially since the average person spends more than 90% of their time indoors. The modelling conducted in this research aims to provide a framework for epidemiological studies by the use of publically available data from fixed outdoor monitoring stations to predict indoor air quality more accurately. Predictions are made using two modelling techniques, the Personal-exposure Activity Location Model (PALM), to predict outdoor air quality at a particular building, and Artificial Neural Networks, to model the indoor/outdoor relationship of the building. This joint approach has been used to predict indoor air concentrations for three inner city commercial buildings in Dublin, where parallel indoor and outdoor diurnal monitoring had been carried out on site. This modelling methodology has been shown to provide reasonable predictions of average NO₂ indoor air quality compared to the monitored data, but did not perform well in the prediction of indoor PM2.5 concentrations. Hence, this approach could be used to determine NO₂ exposures more rigorously of those who work and/or live in the city centre, which can then be linked to potential health impacts. PMID:26633448

  3. Evaluation of Observation-Fused Regional Air Quality Model Results for Population Air Pollution Exposure Estimation

    PubMed Central

    Chen, Gang; Li, Jingyi; Ying, Qi; Sherman, Seth; Perkins, Neil; Rajeshwari, Sundaram; Mendola, Pauline

    2014-01-01

    In this study, Community Multiscale Air Quality (CMAQ) model was applied to predict ambient gaseous and particulate concentrations during 2001 to 2010 in 15 hospital referral regions (HRRs) using a 36-km horizontal resolution domain. An inverse distance weighting based method was applied to produce exposure estimates based on observation-fused regional pollutant concentration fields using the differences between observations and predictions at grid cells where air quality monitors were located. Although the raw CMAQ model is capable of producing satisfying results for O3 and PM2.5 based on EPA guidelines, using the observation data fusing technique to correct CMAQ predictions leads to significant improvement of model performance for all gaseous and particulate pollutants. Regional average concentrations were calculated using five different methods: 1) inverse distance weighting of observation data alone, 2) raw CMAQ results, 3) observation-fused CMAQ results, 4) population-averaged raw CMAQ results and 5) population-averaged fused CMAQ results. It shows that while O3 (as well as NOx) monitoring networks in the HRR regions are dense enough to provide consistent regional average exposure estimation based on monitoring data alone, PM2.5 observation sites (as well as monitors for CO, SO2, PM10 and PM2.5 components) are usually sparse and the difference between the average concentrations estimated by the inverse distance interpolated observations, raw CMAQ and fused CMAQ results can be significantly different. Population-weighted average should be used to account spatial variation in pollutant concentration and population density. Using raw CMAQ results or observations alone might lead to significant biases in health outcome analyses. PMID:24747248

  4. 39 CFR 320.7 - Suspension for advertisements accompanying parcels or periodicals.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 39 Postal Service 1 2010-07-01 2010-07-01 false Suspension for advertisements accompanying parcels... advertisements accompanying parcels or periodicals. (a) The operation of 39 U.S.C. 601(a) (1) through (6) and § 310.2(b) (1) through (6) of this chapter is suspended on all post routes for advertisements...

  5. 78 FR 56248 - Product Change-Parcel Select Negotiated Service Agreement

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-09-12

    ... From the Federal Register Online via the Government Publishing Office POSTAL SERVICE Product Change--Parcel Select Negotiated Service Agreement AGENCY: Postal Service TM . ACTION: Notice. SUMMARY... the Postal Regulatory Commission a Request of the United States Postal Service to Add Parcel...

  6. 77 FR 66193 - Product Change-Parcel Select Negotiated Service Agreement

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-11-02

    ... From the Federal Register Online via the Government Publishing Office POSTAL SERVICE Product Change--Parcel Select Negotiated Service Agreement AGENCY: Postal Service TM . ACTION: Notice. SUMMARY... the Postal Regulatory Commission a Request of the United States Postal Service To Add Parcel...

  7. 77 FR 42780 - Product Change-Parcel Select Negotiated Service Agreement

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-07-20

    ... From the Federal Register Online via the Government Publishing Office POSTAL SERVICE Product Change--Parcel Select Negotiated Service Agreement AGENCY: Postal Service\\TM\\. ACTION: Notice. SUMMARY... Regulatory Commission a Request of the United States Postal Service to Add Parcel Select Contract 4...

  8. 77 FR 42780 - Product Change-Parcel Select Negotiated Service Agreement

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-07-20

    ... From the Federal Register Online via the Government Publishing Office POSTAL SERVICE Product Change--Parcel Select Negotiated Service Agreement AGENCY: Postal Service TM . ACTION: Notice. SUMMARY... Regulatory Commission a Request of the United States Postal Service to Add Parcel Select Contract 5...

  9. 77 FR 42780 - Product Change-Parcel Select Negotiated Service Agreement

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-07-20

    ... From the Federal Register Online via the Government Publishing Office POSTAL SERVICE Product Change--Parcel Select Negotiated Service Agreement AGENCY: Postal Service\\TM\\. ACTION: Notice. SUMMARY... Regulatory Commission a Request of the United States Postal Service to Add Parcel Select Contract 3...

  10. 77 FR 28410 - Product Change-Parcel Select Negotiated Service Agreement

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-05-14

    ... From the Federal Register Online via the Government Publishing Office POSTAL SERVICE Product Change--Parcel Select Negotiated Service Agreement AGENCY: Postal Service\\TM\\. ACTION: Notice. SUMMARY... Commission a Request of the United States Postal Service to Add Parcel Select Contract 1 to...

  11. 76 FR 2930 - Product Change-Parcel Select Negotiated Service Agreement

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-01-18

    ... From the Federal Register Online via the Government Publishing Office POSTAL SERVICE Product Change--Parcel Select Negotiated Service Agreement AGENCY: Postal Service TM . ACTION: Notice. SUMMARY... ] Commission a Request of the United States Postal Service to Add Parcel Select Contract 1 to...

  12. 77 FR 43561 - Proposed Eligibility Criteria for Bound Printed Matter Parcels

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-07-25

    ... 111 Proposed Eligibility Criteria for Bound Printed Matter Parcels AGENCY: Postal Service TM . ACTION... criterion for eligibility of Bound Printed Matter (BPM) parcels by adding a physical density threshold for... matter, weighing no more than 15 pounds and requiring postage payment by permit imprint. BPM is...

  13. Semi-supervised clustering for parcellating brain regions based on resting state fMRI data

    NASA Astrophysics Data System (ADS)

    Cheng, Hewei; Fan, Yong

    2014-03-01

    Many unsupervised clustering techniques have been adopted for parcellating brain regions of interest into functionally homogeneous subregions based on resting state fMRI data. However, the unsupervised clustering techniques are not able to take advantage of exiting knowledge of the functional neuroanatomy readily available from studies of cytoarchitectonic parcellation or meta-analysis of the literature. In this study, we propose a semi-supervised clustering method for parcellating amygdala into functionally homogeneous subregions based on resting state fMRI data. Particularly, the semi-supervised clustering is implemented under the framework of graph partitioning, and adopts prior information and spatial consistent constraints to obtain a spatially contiguous parcellation result. The graph partitioning problem is solved using an efficient algorithm similar to the well-known weighted kernel k-means algorithm. Our method has been validated for parcellating amygdala into 3 subregions based on resting state fMRI data of 28 subjects. The experiment results have demonstrated that the proposed method is more robust than unsupervised clustering and able to parcellate amygdala into centromedial, laterobasal, and superficial parts with improved functionally homogeneity compared with the cytoarchitectonic parcellation result. The validity of the parcellation results is also supported by distinctive functional and structural connectivity patterns of the subregions and high consistency between coactivation patterns derived from a meta-analysis and functional connectivity patterns of corresponding subregions.

  14. Collisional radiative coarse-grain model for ionization in air

    NASA Astrophysics Data System (ADS)

    Panesi, Marco; Lani, Andrea

    2013-05-01

    We present a reduced kinetic mechanism for the modeling of the behavior of the electronic states of the atomic species in air mixtures. The model is built by lumping the electronically excited states of the atomic species and by performing Maxwell-Boltzmann averages of the rate constants describing the elementary kinetic processes of the individual states within each group. The necessary reaction rate coefficients are taken from the model compiled by Bultel et al. ["Collisional-radiative model in air for earth re-entry problems," Phys. Plasmas 13, 043502 (2006), 10.1063/1.2194827]. The reduced number of pseudo-states considered leads to a significant reduction of the computational cost, thus enabling the application of the state of the art collisional radiative models to bi-dimensional and three-dimensional problems. The internal states of the molecular species are assumed to be in equilibrium. The rotational energy mode is assumed to quickly equilibrate with the translational energy mode at the kinetic temperature of the heavy species as opposed to the electronic and the vibrational modes, assumed to be in Maxwell-Boltzmann equilibrium at a common temperature TV. In a first step we validate the model by using simple zero- and one-dimensional test cases for which the full kinetic mechanism can be run efficiently. Finally, the reduced kinetic model is used to analyze the strong non-equilibrium flow surrounding the FIRE II flight experiment during the early part of its re-entry trajectory. It is found that the reduced kinetic mechanism is capable of reproducing the ionizational non-equilibrium phenomena, responsible for the drastic reduction of the radiative heat loads on the space capsules during the re-entry phase.

  15. Improving ammonia emissions in air quality modelling for France

    NASA Astrophysics Data System (ADS)

    Hamaoui-Laguel, Lynda; Meleux, Frédérik; Beekmann, Matthias; Bessagnet, Bertrand; Génermont, Sophie; Cellier, Pierre; Létinois, Laurent

    2014-08-01

    We have implemented a new module to improve the representation of ammonia emissions from agricultural activities in France with the objective to evaluate the impact of such emissions on the formation of particulate matter modelled with the air quality model CHIMERE. A novel method has been set up for the part of ammonia emissions originating from mineral fertilizer spreading. They are calculated using the one dimensional 1D mechanistic model “VOLT'AIR” which has been coupled with data on agricultural practices, meteorology and soil properties obtained at high spatial resolution (cantonal level). These emissions display high spatiotemporal variations depending on soil pH, rates and dates of fertilization and meteorological variables, especially soil temperature. The emissions from other agricultural sources (animal housing, manure storage and organic manure spreading) are calculated using the national spatialised inventory (INS) recently developed in France. The comparison of the total ammonia emissions estimated with the new approach VOLT'AIR_INS with the standard emissions provided by EMEP (European Monitoring and Evaluation Programme) used currently in the CHIMERE model shows significant differences in the spatiotemporal distributions. The implementation of new ammonia emissions in the CHIMERE model has a limited impact on ammonium nitrate aerosol concentrations which only increase at most by 10% on the average for the considered spring period but this impact can be more significant for specific pollution episodes. The comparison of modelled PM10 (particulate matter with aerodynamic diameter smaller than 10 μm) and ammonium nitrate aerosol with observations shows that the use of the new ammonia emission method slightly improves the spatiotemporal correlation in certain regions and reduces the negative bias on average by 1 μg m-3. The formation of ammonium nitrate aerosol depends not only on ammonia concentrations but also on nitric acid availability, which

  16. Air assisted lamellar keratectomy for the corneal haze model.

    PubMed

    Kim, Soohyun; Park, Young Woo; Lee, Euiri; Park, Sang Wan; Park, Sungwon; Kim, Jong Whi; Seong, Je Kyung; Seo, Kangmoon

    2015-01-01

    To standardize the corneal haze model in the resection depth and size for efficient corneal haze development, air assisted lamellar keratectomy was performed. The ex vivo porcine corneas were categorized into four groups depending on the trephined depth: 250 µm (G1), 375 µm (G2), 500 µm(G3) and 750 µm (G4). The stroma was equally ablated at the five measurement sites in all groups. Significant differences were observed between the trephined corneal depths for resection and ablated corneal thickness in G1 (p < 0.001). No significant differences were observed between the trephined corneal depth for resection and the ablated corneal thickness in G2, G3, and G4. The resection percentage was similar in all groups after microscopic imaging of corneal sections. Air assisted lamellar keratectomy (AK) and conventional keratectomy (CK) method were applied to six beagles, after which development of corneal haze was evaluated weekly until postoperative day 28. The occurrence of corneal haze in the AK group was significantly higher than that in the CK group beginning 14 days after surgery. Alpha-smooth muscle actin expression was significantly higher in the AK group (p < 0.001) than the CK group. Air assisted lamellar keratectomy was used to achieve the desired corneal thickness after resection and produce sufficient corneal haze.

  17. Air assisted lamellar keratectomy for the corneal haze model

    PubMed Central

    Kim, Soohyun; Park, Young Woo; Lee, Euiri; Park, Sang Wan; Park, Sungwon; Kim, Jong Whi; Seong, Je Kyung

    2015-01-01

    To standardize the corneal haze model in the resection depth and size for efficient corneal haze development, air assisted lamellar keratectomy was performed. The ex vivo porcine corneas were categorized into four groups depending on the trephined depth: 250 µm (G1), 375 µm (G2), 500 µm (G3) and 750 µm (G4). The stroma was equally ablated at the five measurement sites in all groups. Significant differences were observed between the trephined corneal depths for resection and ablated corneal thickness in G1 (p < 0.001). No significant differences were observed between the trephined corneal depth for resection and the ablated corneal thickness in G2, G3, and G4. The resection percentage was similar in all groups after microscopic imaging of corneal sections. Air assisted lamellar keratectomy (AK) and conventional keratectomy (CK) method were applied to six beagles, after which development of corneal haze was evaluated weekly until postoperative day 28. The occurrence of corneal haze in the AK group was significantly higher than that in the CK group beginning 14 days after surgery. Alpha-smooth muscle actin expression was significantly higher in the AK group (p < 0.001) than the CK group. Air assisted lamellar keratectomy was used to achieve the desired corneal thickness after resection and produce sufficient corneal haze. PMID:25797296

  18. Evaluation of air pollution modelling tools as environmental engineering courseware.

    PubMed

    Souto González, J A; Bello Bugallo, P M; Casares Long, J J

    2004-01-01

    The study of phenomena related to the dispersion of pollutants usually takes advantage of the use of mathematical models based on the description of the different processes involved. This educational approach is especially important in air pollution dispersion, when the processes follow a non-linear behaviour so it is difficult to understand the relationships between inputs and outputs, and in a 3D context where it becomes hard to analyze alphanumeric results. In this work, three different software tools, as computer solvers for typical air pollution dispersion phenomena, are presented. Each software tool developed to be implemented on PCs, follows approaches that represent three generations of programming languages (Fortran 77, VisualBasic and Java), applied over three different environments: MS-DOS, MS-Windows and the world wide web. The software tools were tested by students of environmental engineering (undergraduate) and chemical engineering (postgraduate), in order to evaluate the ability of these software tools to improve both theoretical and practical knowledge of the air pollution dispersion problem, and the impact of the different environment in the learning process in terms of content, ease of use and visualization of results. PMID:15193095

  19. A NEW COMBINED LOCAL AND NON-LOCAL PBL MODEL FOR METEOROLOGY AND AIR QUALITY MODELING

    EPA Science Inventory

    A new version of the Asymmetric Convective Model (ACM) has been developed to describe sub-grid vertical turbulent transport in both meteorology models and air quality models. The new version (ACM2) combines the non-local convective mixing of the original ACM with local eddy diff...

  20. Space-Time Analysis of the Air Quality Model Evaluation International Initiative (AQMEII) Phase 1 Air Quality Simulations

    EPA Science Inventory

    This study presents an evaluation of summertime daily maximum ozone concentrations over North America (NA) and Europe (EU) using the database generated during Phase 1 of the Air Quality Model Evaluation International Initiative (AQMEII). The analysis focuses on identifying tempor...

  1. Assimilation of Satellite Data in Regional Air Quality Models

    NASA Technical Reports Server (NTRS)

    Mcnider, Richard T.; Norris, William B.; Casey, Daniel; Pleim, Jonathan E.; Roselle, Shawn J.; Lapenta, William M.

    1997-01-01

    In terms of important uncertainty in regional-scale air-pollution models, probably no other aspect ranks any higher than the current ability to specify clouds and soil moisture on the regional scale. Because clouds in models are highly parameterized, the ability of models to predict the correct spatial and radiative characteristics is highly suspect and subject to large error. The poor representation of cloud fields from point measurements at National Weather Services stations and the almost total absence of surface moisture availability observations has made assimilation of these variables difficult to impossible. Yet, the correct inclusion of clouds and surface moisture are of first-order importance in regional-scale photochemistry.

  2. Modeling and Analysis of Aluminum/Air Fuel Cell

    NASA Astrophysics Data System (ADS)

    Leon, Armando J.

    The technical and scientific challenges to provide reliable sources energy for US and global economy are enormous tasks, and especially so when combined with strategic and recent economic concerns of the last five years. It is clear that as part of the mix of energy sources necessary to deal with these challenges, fuel cells technology will play critical or even a central role. The US Department of Energy, as well as a number of the national laboratories and academic institutions have been aware of the importance such technology for some time. Recently, car manufacturers, transportation experts, and even utilities are paying attention to this vital source of energy for the future. In this thesis, a review of the main fuel cell technologies is presented with the focus on the modeling, and control of one particular and promising fuel cell technology, aluminum air fuel cells. The basic principles of this fuel cell technology are presented. A major part of the study consists of a description of the electrochemistry of the process, modeling, and simulations of aluminum air FC using Matlab Simulink(TM). The controller design of the proposed model is also presented. In sequel, a power management unit is designed and analyzed as an alternative source of power. Thus, the system commutes between the fuel cell output and the alternative power source in order to fulfill a changing power load demand. Finally, a cost analysis and assessment of this technology for portable devices, conclusions and future recommendations are presented.

  3. NASA Air Force Cost Model (NAFCOM): Capabilities and Results

    NASA Technical Reports Server (NTRS)

    McAfee, Julie; Culver, George; Naderi, Mahmoud

    2011-01-01

    NAFCOM is a parametric estimating tool for space hardware. Uses cost estimating relationships (CERs) which correlate historical costs to mission characteristics to predict new project costs. It is based on historical NASA and Air Force space projects. It is intended to be used in the very early phases of a development project. NAFCOM can be used at the subsystem or component levels and estimates development and production costs. NAFCOM is applicable to various types of missions (crewed spacecraft, uncrewed spacecraft, and launch vehicles). There are two versions of the model: a government version that is restricted and a contractor releasable version.

  4. Air pollution modifies floral scent trails

    NASA Astrophysics Data System (ADS)

    McFrederick, Quinn S.; Kathilankal, James C.; Fuentes, Jose D.

    Floral hydrocarbons provide essential signals to attract pollinators. As soon as they are emitted to the atmosphere, however, hydrocarbons are destroyed by chemical reactions involving pollutants such as ozone. It is therefore likely that increased air pollution interferes with pollinator attracting hydrocarbon signals. To test this hypothesis, a Lagrangian diffusion model was used to determine the position of air parcels away from hydrocarbon sources and to estimate the rate of chemical destruction of hydrocarbons as air parcels moved across the landscape. The hydrocarbon compounds linalool, β-myrcene, and β-ocimene were chosen because they are known to be common scents released from flowers. The suppressed ambient abundances of volatile organic compounds were determined in response to increased regional levels of ozone, hydroxyl, and nitrate radicals. The results indicate that the documented increases in air pollution concentrations, from pre-industrial to present times, can lead to reductions in volatile compound concentrations insects detect as they pollinate flowers. For highly reactive volatiles the maximum downwind distance from the source at which pollinators can detect the scents may have changed from kilometers during pre-industrial times to <200 m during the more polluted conditions of present times. The increased destruction of floral signals in polluted air masses may have important implications for both pollinators and signaling plants. When patches of flowers are further apart than the visual range of pollinators, such as in fragmented landscapes, the loss of scent signals may mean that pollinators spend more time searching for patches and less time foraging. This decrease in pollinator foraging efficiency will simultaneously decrease the pollinator's reproductive output and the amount of pollen flow in flowering plants.

  5. Robust brain parcellation using sparse representation on resting-state fMRI.

    PubMed

    Zhang, Yu; Caspers, Svenja; Fan, Lingzhong; Fan, Yong; Song, Ming; Liu, Cirong; Mo, Yin; Roski, Christian; Eickhoff, Simon; Amunts, Katrin; Jiang, Tianzi

    2015-11-01

    Resting-state fMRI (rs-fMRI) has been widely used to segregate the brain into individual modules based on the presence of distinct connectivity patterns. Many parcellation methods have been proposed for brain parcellation using rs-fMRI, but their results have been somewhat inconsistent, potentially due to various types of noise. In this study, we provide a robust parcellation method for rs-fMRI-based brain parcellation, which constructs a sparse similarity graph based on the sparse representation coefficients of each seed voxel and then uses spectral clustering to identify distinct modules. Both the local time-varying BOLD signals and whole-brain connectivity patterns may be used as features and yield similar parcellation results. The robustness of our method was tested on both simulated and real rs-fMRI datasets. In particular, on simulated rs-fMRI data, sparse representation achieved good performance across different noise levels, including high accuracy of parcellation and high robustness to noise. On real rs-fMRI data, stable parcellation of the medial frontal cortex (MFC) and parietal operculum (OP) were achieved on three different datasets, with high reproducibility within each dataset and high consistency across these results. Besides, the parcellation of MFC was little influenced by the degrees of spatial smoothing. Furthermore, the consistent parcellation of OP was also well corresponding to cytoarchitectonic subdivisions and known somatotopic organizations. Our results demonstrate a new promising approach to robust brain parcellation using resting-state fMRI by sparse representation.

  6. Analysis of air pollution from swine production by using air dispersion model and GIS in Quebec.

    PubMed

    Sarr, Joachim H; Goïta, Kalifa; Desmarais, Camille

    2010-01-01

    Swine production, the second most important contributor to Quebec's agricultural revenue, faces many problems. Intensive piggeries, with up to 599 animal units, are used to raise finishing pigs for slaughter. Among the great number of gaseous species emitted to the atmospheric environment from livestock buildings and manure storage units is NH3, which is one of the most important and most offensive with respect to human health. Under appropriate meteorological and topographical conditions, gaseous contaminants can spread and cause a public nuisance--up to a 1-km radius around the farm. To mitigate these effects, the Quebec Government adopted regulations that set minimum buffer distances to be observed by any expansion of an existing or new pig farm. The objectives of this study were (i) to assess the efficiency of the current buffer distance prescriptions in Quebec in mitigating effects of air pollution from swine units and (ii) to identify potential areas for establishing pig farm operations that will not be offensive to people. The air dispersion American Meteorological Society/Environmental Protection Agency Regulatory Model (AERMOD) with receptors distributed at 1.6 km around each source was used first, followed by a spatial geographic information system (GIS) model. Results from the dispersion model showed that the highest hourly concentration with a 99.5% compliance frequency for a single farm was 3078.1 microg/m3 and exceeded the NH3 odor criterion hourly standard set by the Quebec Government at 183.4 microg/m3. Thus, for public safety, densely populated areas like housing developments must be located >1300 m from a pig farm. This distance is in the range of setback distances (723 to 1447 m) obtained by using abacuses defined in the L'Erable Regional County Municipality. That is why we can say the current rules established by the Quebec Government, if rigorously applied, can prevent odor nuisance, due to NH3 emission, from swine farms. In the spatial model

  7. Modeling Air Traffic Management Technologies with a Queuing Network Model of the National Airspace System

    NASA Technical Reports Server (NTRS)

    Long, Dou; Lee, David; Johnson, Jesse; Gaier, Eric; Kostiuk, Peter

    1999-01-01

    This report describes an integrated model of air traffic management (ATM) tools under development in two National Aeronautics and Space Administration (NASA) programs -Terminal Area Productivity (TAP) and Advanced Air Transport Technologies (AATT). The model is made by adjusting parameters of LMINET, a queuing network model of the National Airspace System (NAS), which the Logistics Management Institute (LMI) developed for NASA. Operating LMINET with models of various combinations of TAP and AATT will give quantitative information about the effects of the tools on operations of the NAS. The costs of delays under different scenarios are calculated. An extension of Air Carrier Investment Model (ACIM) under ASAC developed by the Institute for NASA maps the technologies' impacts on NASA operations into cross-comparable benefits estimates for technologies and sets of technologies.

  8. Performance criteria to evaluate air quality modeling applications

    NASA Astrophysics Data System (ADS)

    Thunis, P.; Pederzoli, A.; Pernigotti, D.

    2012-11-01

    A set of statistical indicators fit for air quality model evaluation is selected based on experience and literature: The Root Mean Square Error (RMSE), the bias, the Standard Deviation (SD) and the correlation coefficient (R). Among these the RMSE is proposed as the key one for the description of the model skill. Model Performance Criteria (MPC) to investigate whether model results are 'good enough' for a given application are calculated based on the observation uncertainty (U). The basic concept is to allow for model results a similar margin of tolerance (in terms of uncertainty) as for observations. U is pollutant, concentration level and station dependent, therefore the proposed MPC are normalized by U. Some composite diagrams are adapted or introduced to visualize model performance in terms of the proposed MPC and are illustrated in a real modeling application. The Target diagram, used to visualize the RMSE, is adapted with a new normalization on its axis, while complementary diagrams are proposed. In this first application the dependence of U on concentrations level is ignored, and an assumption on the pollutant dependent relative error is made. The advantages of this new approach are finally described.

  9. Model-based estimation of changes in air temperature seasonality

    NASA Astrophysics Data System (ADS)

    Barbosa, Susana; Trigo, Ricardo

    2010-05-01

    Seasonality is a ubiquitous feature in climate time series. Climate change is expected to involve not only changes in the mean of climate parameters but also changes in the characteristics of the corresponding seasonal cycle. Therefore the identification and quantification of changes in seasonality is a highly relevant topic in climate analysis, particularly in a global warming context. However, the analysis of seasonality is far from a trivial task. A key challenge is the discrimination between long-term changes in the mean and long-term changes in the seasonal pattern itself, which requires the use of appropriate statistical approaches in order to be able to distinguish between overall trends in the mean and trends in the seasons. Model based approaches are particularly suitable for the analysis of seasonality, enabling to assess uncertainties in the amplitude and phase of seasonal patterns within a well defined statistical framework. This work addresses the changes in the seasonality of air temperature over the 20th century. The analysed data are global air temperature values close to surface (2m above ground) and mid-troposphere (500 hPa geopotential height) from the recently developed 20th century reanalysis. This new 3-D Reanalysis dataset is available since 1891, considerably extending all other Reanalyses currently in use (e.g. NCAR, ECWMF), and was obtained with the Ensemble Filter (Compo et al., 2006) by assimilation of pressure observations into a state-of-the-art atmospheric general circulation model that includes the radiative effects of historical time-varying CO2 concentrations, volcanic aerosol emissions and solar output variations. A modeling approach based on autoregression (Barbosa et al, 2008; Barbosa, 2009) is applied within a Bayesian framework for the estimation of a time varying seasonal pattern and further quantification of changes in the amplitude and phase of air temperature over the 20th century. Barbosa, SM, Silva, ME, Fernandes, MJ

  10. An optimization model for the US Air-Traffic System

    NASA Technical Reports Server (NTRS)

    Mulvey, J. M.

    1986-01-01

    A systematic approach for monitoring U.S. air traffic was developed in the context of system-wide planning and control. Towards this end, a network optimization model with nonlinear objectives was chosen as the central element in the planning/control system. The network representation was selected because: (1) it provides a comprehensive structure for depicting essential aspects of the air traffic system, (2) it can be solved efficiently for large scale problems, and (3) the design can be easily communicated to non-technical users through computer graphics. Briefly, the network planning models consider the flow of traffic through a graph as the basic structure. Nodes depict locations and time periods for either individual planes or for aggregated groups of airplanes. Arcs define variables as actual airplanes flying through space or as delays across time periods. As such, a special case of the network can be used to model the so called flow control problem. Due to the large number of interacting variables and the difficulty in subdividing the problem into relatively independent subproblems, an integrated model was designed which will depict the entire high level (above 29000 feet) jet route system for the 48 contiguous states in the U.S. As a first step in demonstrating the concept's feasibility a nonlinear risk/cost model was developed for the Indianapolis Airspace. The nonlinear network program --NLPNETG-- was employed in solving the resulting test cases. This optimization program uses the Truncated-Newton method (quadratic approximation) for determining the search direction at each iteration in the nonlinear algorithm. It was shown that aircraft could be re-routed in an optimal fashion whenever traffic congestion increased beyond an acceptable level, as measured by the nonlinear risk function.

  11. SMI-32 parcellates the visual cortical areas of the marmoset.

    PubMed

    Baldauf, Zsolt B

    The distribution pattern of SMI-32-immunoreactivity (SMI-32-ir) of neuronal elements was examined in the visual cortical areas of marmoset monkey. Layer IV of the primary visual cortex (V1) and layers III and V of the extrastriate areas showed the most abundant SMI-32-ir. The different areal and laminar distribution of SMI-32-ir allowed the distinction between various extrastriate areas and determined their exact anatomical boundaries in the New World monkey, Callithrix penicillata. It is shown here that the parcellating nature of SMI-32 described earlier in the visual cortical areas of other mammals - including Old World monkeys - is also present in the marmoset. Furthermore, a comparison became possible between the chemoanatomical organization of New World and Old World primates' visual cortical areas.

  12. Air quality modeling of selected aromatic and non-aromatic air toxics in the Houston urban and industrial airshed

    NASA Astrophysics Data System (ADS)

    Coarfa, Violeta Florentina

    2007-12-01

    Air toxics, also called hazardous air pollutants (HAPs), pose a serious threat to human health and the environment. Their study is important in the Houston area, where point sources, mostly located along the Ship Channel, mobile and area sources contribute to large emissions of such toxic pollutants. Previous studies carried out in this area found dangerous levels of different HAPs in the atmosphere. This thesis presents several studies that were performed for the aromatic and non-aromatic air toxics in the HGA. For these studies we developed several tools: (1) a refined chemical mechanism, which explicitly represents 18 aromatic air toxics that were lumped under two model species by the previous version, based on their reactivity with the hydroxyl radical; (2) an engineering version of an existing air toxics photochemical model that enables us to perform much faster long-term simulations compared to the original model, that leads to a 8--9 times improvement in the running time across different computing platforms; (3) a combined emission inventory based on the available emission databases. Using the developed tools, we quantified the mobile source impact on a few selected air toxics, and analyzed the temporal and spatial variation of selected aromatic and non-aromatic air toxics in a few regions within the Houston area; these regions were characterized by different emissions and environmental conditions.

  13. Future Air Traffic Growth and Schedule Model User's Guide

    NASA Technical Reports Server (NTRS)

    Kimmel, William M. (Technical Monitor); Smith, Jeremy C.; Dollyhigh, Samuel M.

    2004-01-01

    The Future Air Traffic Growth and Schedule Model was developed as an implementation of the Fratar algorithm to project future traffic flow between airports in a system and of then scheduling the additional flights to reflect current passenger time-of-travel preferences. The methodology produces an unconstrained future schedule from a current (or baseline) schedule and the airport operations growth rates. As an example of the use of the model, future schedules are projected for 2010 and 2022 for all flights arriving at, departing from, or flying between all continental United States airports that had commercial scheduled service for May 17, 2002. Inter-continental US traffic and airports are included and the traffic is also grown with the Fratar methodology to account for their arrivals and departures to the continental US airports. Input data sets derived from the Official Airline Guide (OAG) data and FAA Terminal Area Forecast (TAF) are included in the examples of the computer code execution.

  14. Future Air Traffic Growth and Schedule Model, Supplement

    NASA Technical Reports Server (NTRS)

    Kimmel, William M. (Technical Monitor); Smith, Jeremy C.; Dollyhigh, Samuel M.

    2004-01-01

    The Future Air Traffic Growth and Schedule Model was developed as an implementation of the Fratar algorithm to project future traffic flow between airports in a system and of then scheduling the additional flights to reflect current passenger time-of-travel preferences. The methodology produces an unconstrained future schedule from a current (or baseline) schedule and the airport operations growth rates. As an example of the use of the model, future schedules are projected for 2010 and 2022 for all flights arriving at, departing from, or flying between all continental United States airports that had commercial scheduled service for May 17, 2002. Inter-continental US traffic and airports are included and the traffic is also grown with the Fratar methodology to account for their arrivals and departures to the continental US airports. Input data sets derived from the Official Airline Guide (OAG) data and FAA Terminal Area Forecast (TAF) are included in the examples of the computer code execution.

  15. Validation of two air quality models for Indian mining conditions.

    PubMed

    Chaulya, S K; Ahmad, M; Singh, R S; Bandopadhyay, L K; Bondyopadhay, C; Mondal, G C

    2003-02-01

    All major mining activity particularly opencast mining contributes to the problem of suspended particulate matter (SPM) directly or indirectly. Therefore, assessment and prediction are required to prevent and minimize the deterioration of SPM due to various opencast mining operations. Determination of emission rate of SPM for these activities and validation of air quality models are the first and foremost concern. In view of the above, the study was taken up for determination of emission rate for SPM to calculate emission rate of various opencast mining activities and validation of commonly used two air quality models for Indian mining conditions. To achieve the objectives, eight coal and three iron ore mining sites were selected to generate site specific emission data by considering type of mining, method of working, geographical location, accessibility and above all resource availability. The study covers various mining activities and locations including drilling, overburden loading and unloading, coal/mineral loading and unloading, coal handling or screening plant, exposed overburden dump, stock yard, workshop, exposed pit surface, transport road and haul road. Validation of the study was carried out through Fugitive Dust Model (FDM) and Point, Area and Line sources model (PAL2) by assigning the measured emission rate for each mining activity, meteorological data and other details of the respective mine as an input to the models. Both the models were run separately for the same set of input data for each mine to get the predicted SPM concentration at three receptor locations for each mine. The receptor locations were selected such a way that at the same places the actual filed measurement were carried out for SPM concentration. Statistical analysis was carried out to assess the performance of the models based on a set measured and predicted SPM concentration data. The value of coefficient of correlation for PAL2 and FDM was calculated to be 0.990-0.994 and 0

  16. THE EMERGENCE OF NUMERICAL AIR QUALITY FORCASTING MODELS AND THEIR APPLICATIONS

    EPA Science Inventory

    In recent years the U.S. and other nations have begun programs for short-term local through regional air quality forecasting based upon numerical three-dimensional air quality grid models. These numerical air quality forecast (NAQF) models and systems have been developed and test...

  17. THE EMERGENCE OF NUMERICAL AIR QUALITY FORECASTING MODELS AND THEIR APPLICATION

    EPA Science Inventory

    In recent years the U.S. and other nations have begun programs for short-term local through regional air quality forecasting based upon numerical three-dimensional air quality grid models. These numerical air quality forecast (NAQF) models and systems have been developed and test...

  18. Application of SIM-air modeling tools to assess air quality in Indian cities

    NASA Astrophysics Data System (ADS)

    Guttikunda, Sarath K.; Jawahar, Puja

    2012-12-01

    A prerequisite to an air quality management plan for a city is some idea of the main sources of pollution and their contributions for a city. This paper presents the results of an application of the SIM-air modeling tool in six Indian cities - Pune, Chennai, Indore, Ahmedabad, Surat, and Rajkot. Using existing and publicly available data, we put together a baseline of multi-pollutant emissions for each of the cities and then calculate concentrations, health impacts, and model alternative scenarios for 2020. The measured annual PM10 (particulate matter with aerodynamic diameter less than 10 micron meter) concentrations in μg m-3 averaged 94.7 ± 45.4 in Pune, 73.1 ± 33.7 in Chennai, 118.8 ± 44.3 in Indore, 94.0 ± 20.4 in Ahmedabad, 89.4 ± 12.1 in Surat, and 105.0 ± 25.6 in Rajkot, all exceeding the annual standard of 60 μg m-3. The PM10 inventory in tons/year for the year 2010 of 38,400 in Pune, 50,200 in Chennai, 18,600 in Indore, 31,900 in Ahmedabad, 20,000 in Surat, and 14,000 in Rajkot, is further spatially segregated into 1 km grids and includes all known sources such as transport, road dust, residential, power plants, industries (including the brick kilns), waste burning, and diesel generator sets. We use the ATMoS chemical transport model to validate the emissions inventory and estimate an annual premature mortality due to particulate pollution of 15,200 for the year 2010 for the six cities. Of the estimated 21,400 premature deaths in the six cities in 2020, we estimate that implementation of the six interventions in the transport and brick kiln sectors, can potentially save 5870 lives (27%) annually and result in an annual reduction of 16.8 million tons of carbon dioxide emissions in the six cities.

  19. PREFACE SPECIAL ISSUE ON MODEL EVALUATION: EVALUATION OF URBAN AND REGIONAL EULERIAN AIR QUALITY MODELS

    EPA Science Inventory

    The "Preface to the Special Edition on Model Evaluation: Evaluation of Urban and Regional Eulerian Air Quality Models" is a brief introduction to the papers included in a special issue of Atmospheric Environment. The Preface provides a background for the papers, which have thei...

  20. AIR QUALITY MODELING AT NEIGHBORHOOD SCALES TO IMPROVE HUMAN EXPOSURE ASSESSMENT

    EPA Science Inventory

    Air quality modeling is an integral component of risk assessment and of subsequent development of effective and efficient management of air quality. Urban areas introduce of fresh sources of pollutants into regional background producing significant spatial variability of the co...

  1. Atmospheric Modelling for Air Quality Study over the complex Himalayas

    NASA Astrophysics Data System (ADS)

    Surapipith, Vanisa; Panday, Arnico; Mukherji, Aditi; Banmali Pradhan, Bidya; Blumer, Sandro

    2014-05-01

    An Atmospheric Modelling System has been set up at International Centre for Integrated Mountain Development (ICIMOD) for the assessment of Air Quality across the Himalaya mountain ranges. The Weather Research and Forecasting (WRF) model version 3.5 has been implemented over the regional domain, stretching across 4995 x 4455 km2 centred at Ichhyakamana , the ICIMOD newly setting-up mountain-peak station (1860 m) in central Nepal, and covering terrains from sea-level to the Everest (8848 m). Simulation is carried out for the winter time period, i.e. December 2012 to February 2013, when there was an intensive field campaign SusKat, where at least 7 super stations were collecting meteorology and chemical parameters on various sites. The very complex terrain requires a high horizontal resolution (1 × 1 km2), which is achieved by nesting the domain of interest, e.g. Kathmandu Valley, into 3 coarser ones (27, 9, 3 km resolution). Model validation is performed against the field data as well as satellite data, and the challenge of capturing the necessary atmospheric processes is discussed, before moving forward with the fully coupled chemistry module (WRF-Chem), having local and regional emission databases as input. The effort aims at finding a better understanding of the atmospheric processes and air quality impact on the mountain population, as well as the impact of the long-range transport, particularly of Black Carbon aerosol deposition, to the radiative budget over the Himalayan glaciers. The higher rate of snowcap melting, and shrinkage of permafrost as noticed by glaciologists is a concern. Better prediction will supply crucial information to form the proper mitigation and adaptation strategies for saving people lives across the Himalayas in the changing climate.

  2. Regional Air Toxics Modeling in California's San Francisco Bay Area

    NASA Astrophysics Data System (ADS)

    Martien, P. T.; Tanrikulu, S.; Tran, C.; Fairley, D.; Jia, Y.; Fanai, A.; Reid, S.; Yarwood, G.; Emery, C.

    2011-12-01

    Regional toxics modeling conducted for California's San Francisco Bay Area (SFBA) estimated potential cancer risk from diesel particulate matter (DPM) and four key reactive toxic gaseous pollutants (1,3-butadiene, benzene, formaldehyde, and acetaldehyde). Concentrations of other non-cancerous gaseous toxic air contaminants, including acrolein, were also generated. In this study, meteorological fields generated from July and December periods in 2000 and emissions from 2005 provided inputs to a three-dimensional air quality model at high spatial resolution (1x1 km^2 grid), from which a baseline set of annual risk values was estimated. Simulated risk maps show highest annual average DPM concentrations and cancer risks were located near and downwind of major freeways and near the Port of Oakland, a major container port in the area. Population weighted risks, using 2000 census data, were found to be highest in highly urbanized areas adjacent to significant DPM sources. For summer, the ratio of mean measured elemental carbon to mean modeled DPM was 0.78, conforming roughly to expectations. But for winter the ratio is 1.13, suggesting other sources of elemental carbon, such as wood smoke, are important. Simulated annual estimates for benzene and 1-3, butadiene compared well to measured annual estimates. Simulated acrolein and formaldehyde significantly under-predicted observed values. Simulations repeated using projected 2015 toxic emissions predicted that potential cancer risk dropped significantly in all areas throughout the SFBA. Emissions estimates for 2015 included the State of California's recently adopted on-road truck rule. Emission estimates of DPM are projected to drop about 70% between 2005 and 2015 in the SFBA, with a commensurate reduction in potential cancer risks. However, due to projected shifts in population during this period, with urban densification close to DPM sources outpacing emission reductions, there are some areas where population-weighted risks

  3. The balance model of oxygen enrichment of atmospheric air

    NASA Astrophysics Data System (ADS)

    Popov, Alexander

    2013-04-01

    The study of turnover of carbon and oxygen is an important line of scientific investigation. This line takes on special significance in conditions of soil degradation, which leads to the excess content of carbon dioxide and, as result, decrease of oxygen in the atmosphere. The aim of this article is a statement the balance model of oxygen enrichment of atmospheric air (ratio O/C) depending on consumption and assimilation by plants of dissolved organic matter (DOM) and the value of the oxidation-reduction potential (Eh). Basis of model was the following: green vascular plants are facultative heterotrophic organisms with symbiotic digestion and nutrition. According to the trophology viewpoint, the plant consumption of organic compounds broadens greatly a notion about the plant nutrition and ways of its regulation. In particular, beside the main known cycle of carbon: plant - litter - humus - carbon dioxide - plant, there is the second carbon cycle (turnover of organic compounds): plant - litter - humus - DOM - plant. The biogeochemical meaning of consumption of organic compounds by plants is that plants build the structural and functional blocks of biological macromolecules in their bodies. It provides receiving of a certain "energy payoff" by plants, which leads to increase of plant biomass by both an inclusion of allochthonous organic molecules in plant tissues, and positive effect of organic compounds on plant metabolic processes. One more of powerful ecological consequence of a heterotrophic nutrition of green plants is oxygen enrichment of atmospheric air. As the organic molecules in the second biological cycle of carbon are built in plants without considerable chemical change, the atmospheric air is enriched on that amount of oxygen, which would be required on oxidation of the organic molecules absorbed by plants, in result. It was accepted that: plant-soil system was climax, the plant community was grassy, initial contents of carbon in phytomass was accepted

  4. Modelling of air pollution on a military airfield

    NASA Astrophysics Data System (ADS)

    Brzozowski, Krzysztof; Kotlarz, Wojciech

    The paper presents a numerical study of exhaust emission and pollutant dispersion of carbon monoxide on a military airfield. Investigations have been carried out for typical conditions of aircraft usage in the Polish Air Force Academy in Dęblin. Two different types of aircraft have been taken into account. One of them is an MI-2 helicopter, the second is a TS-11 plane. Both are used in military pilot education in Poland. Exhaust emission of CO from those aircrafts has been obtained in an experiment carried out on an engine test stand. CO concentrations have been calculated for different meteorological conditions (averaged from 5 years observations) and selected conditions of aircraft use. The finite volume method has been used to discretise the equation describing the process of pollutant dispersion. In addition, the two-cycle decomposition method has been employed to solve the set of ordinary differential equations of the first order obtained after discretisation of the advection-diffusion equation. A meteorological pre-processor, based on relationships resulting from the Monin-Obukhov theory, is used to define eddy diffusivity and the profile of air speed in the lower layer of the atmosphere. In the paper, the computer model and calculated average concentration of CO in the Dęblin airfield during typical flights are presented. The goal of the computational analysis is to predict CO pollution level in the workplace of aircraft service personnel.

  5. Numerical models for afterburning of TNT detonation products in air

    NASA Astrophysics Data System (ADS)

    Donahue, L.; Zhang, F.; Ripley, R. C.

    2013-11-01

    Afterburning occurs when fuel-rich explosive detonation products react with oxygen in the surrounding atmosphere. This energy release can further contribute to the air blast, resulting in a more severe explosion hazard particularly in confined scenarios. The primary objective of this study was to investigate the influence of the products equation of state (EOS) on the prediction of the efficiency of trinitrotoluene (TNT) afterburning and the times of arrival of reverberating shock waves in a closed chamber. A new EOS is proposed, denoted the Afterburning (AB) EOS. This EOS employs the JWL EOS in the high pressure regime, transitioning to a Variable-Gamma (VG) EOS at lower pressures. Simulations of three TNT charges suspended in a explosion chamber were performed. When compared to numerical results using existing methods, it was determined that the Afterburning EOS delays the shock arrival times giving better agreement with the experimental measurements in the early to mid time. In the late time, the Afterburning EOS roughly halved the error between the experimental measurements and results obtained using existing methods. Use of the Afterburning EOS for products with the Variable-Gamma EOS for the surrounding air further significantly improved results, both in the transient solution and the quasi-static pressure. This final combination of EOS and mixture model is recommended for future studies involving afterburning explosives, particularly those in partial and full confinement.

  6. Air Quality Modeling of Ozone Radical Precursors in Houston

    NASA Astrophysics Data System (ADS)

    Rappenglueck, B.; Czader, B.; Li, X.

    2013-05-01

    The Houston-Galveston area has one of the highest ozone concentrations in the U.S., often exceeding the U.S. National Ambient Air Quality Standard for ozone. Photochemical modeling of ozone formation in the Houston area generally underestimates the concentrations of free radical precursors contributing to ozone formation. Here we present modeling results using the Weather Research Forecast - Community Multiscale Air Quality (WRF-CMAQ) modeling system for the Houston-Galveston area. Meteorological parameters predicted by WRF are well simulated most of the time, including planetary boundary layer heights. Air quality simulations for the Houston-Galveston-Brazoria area using the combined WRF-SMOKE-CMAQ system showed overall good results for ozone and many other trace gases. HONO morning peaks are no longer underpredicted, on some occasions they are slightly overpredicted, which can be linked to NO2 overprediction. However, CMAQ mispredicts other trace gases like HO2, H2O2 and CH3OOH concentrations. The WRF-SMOKE-CMAQ system was also used to elucidate the relative importance of various photolysis processes as radical sources in the Houston atmosphere. Morning HOx formation is dominated by HONO while ozone contributes the most during midday. HONO contribution to HOx formation is more pronounced at the surface layer where most of it is formed. On the other hand, radical production from ozone is more important at elevated levels where higher concentrations of ozone are observed. Formaldehyde contributes up to 40% and also peaks during mid-day, but on days when high morning concentrations of formaldehyde are observed its contribution to HOx in the morning exceeds that of ozone. Photolysis of H2O2 is a minor contributor to radical levels. The process analysis tool available in CMAQ was utilized to analyze photochemical processes leading to ozone production and chemical transformations along trajectories linking a site at the Houston Ship Channel and the University of

  7. Atmospheric Boundary Layer Modeling for Combined Meteorology and Air Quality Systems

    EPA Science Inventory

    Atmospheric Eulerian grid models for mesoscale and larger applications require sub-grid models for turbulent vertical exchange processes, particularly within the Planetary Boundary Layer (PSL). In combined meteorology and air quality modeling systems consistent PSL modeling of wi...

  8. Air Pollution Exposure Model for Individuals (EMI) in Health Studies

    EPA Science Inventory

    In health studies, traffic-related air pollution is associated with adverse respiratory effects. Due to cost and participant burden of personal measurements, health studies often estimate exposures using local ambient air monitors. Since outdoor levels do not necessarily reflect ...

  9. Equivalent Air Spring Suspension Model for Quarter-Passive Model of Passenger Vehicles

    PubMed Central

    Abid, Haider J.; Chen, Jie; Nassar, Ameen A.

    2015-01-01

    This paper investigates the GENSIS air spring suspension system equivalence to a passive suspension system. The SIMULINK simulation together with the OptiY optimization is used to obtain the air spring suspension model equivalent to passive suspension system, where the car body response difference from both systems with the same road profile inputs is used as the objective function for optimization (OptiY program). The parameters of air spring system such as initial pressure, volume of bag, length of surge pipe, diameter of surge pipe, and volume of reservoir are obtained from optimization. The simulation results show that the air spring suspension equivalent system can produce responses very close to the passive suspension system. PMID:27351020

  10. Equivalent Air Spring Suspension Model for Quarter-Passive Model of Passenger Vehicles.

    PubMed

    Abid, Haider J; Chen, Jie; Nassar, Ameen A

    2015-01-01

    This paper investigates the GENSIS air spring suspension system equivalence to a passive suspension system. The SIMULINK simulation together with the OptiY optimization is used to obtain the air spring suspension model equivalent to passive suspension system, where the car body response difference from both systems with the same road profile inputs is used as the objective function for optimization (OptiY program). The parameters of air spring system such as initial pressure, volume of bag, length of surge pipe, diameter of surge pipe, and volume of reservoir are obtained from optimization. The simulation results show that the air spring suspension equivalent system can produce responses very close to the passive suspension system.

  11. RESOLVING NEIGHBORHOOD-SCALE AIR TOXICS MODELING: A CASE STUDY IN WILMINGTON, CALIFORNIA

    EPA Science Inventory

    Air quality modeling is useful for characterizing exposures to air pollutants. While models typically provide results on regional scales, there is a need for refined modeling approaches capable of resolving concentrations on the scale of tens of meters, across modeling domains 1...

  12. Air Conditioning Stall Phenomenon Testing, Model Development, and Simulation

    SciTech Connect

    Irminger, Philip; Rizy, D Tom; Li, Huijuan; Smith, Travis; Rice, C Keith; Li, Fangxing; Adhikari, Sarina

    2012-01-01

    Electric distribution systems are experiencing power quality issues of extended reduced voltage due to fault-induced delayed voltage recovery (FIDVR). FIDVR occurs in part because modern air conditioner (A/C) and heat pump compressor motors are much more susceptible to stalling during a voltage sag or dip such as a sub-transmission fault. They are more susceptible than older A/C compressor motors due to the low inertia of these newer and more energy efficient motors. There is a concern that these local reduced voltage events on the distribution system will become more frequent and prevalent and will combine over larger areas and challenge transmission system voltage and ultimately power grid reliability. The Distributed Energy Communications and Controls (DECC) Laboratory at Oak Ridge National Laboratory (ORNL) has been employed to (1) test, (2) characterize and (3) model the A/C stall phenomenon.

  13. Air-Flow Simulation in Realistic Models of the Trachea

    SciTech Connect

    Deschamps, T; Schwartz, P; Trebotich, D

    2004-12-09

    In this article we present preliminary results from a new technique for flow simulation in realistic anatomical airways. The airways are extracted by means of Level-Sets methods that accurately model the complex and varying surfaces of anatomical objects. The surfaces obtained are defined at the sub-pixel level where they intersect the Cartesian grid of the image domain. It is therefore straightforward to construct embedded boundary representations of these objects on the same grid, for which recent work has enabled discretization of the Navier- Stokes equations for incompressible fluids. While most classical techniques require construction of a structured mesh that approximates the surface in order to extrapolate a 3D finite-element gridding of the whole volume, our method directly simulates the air-flow inside the extracted surface without losing any complicated details and without building additional grids.

  14. Hybrid Air Quality Modeling Approach for use in the Hear-road Exposures to Urban air pollutant Study(NEXUS)

    EPA Science Inventory

    The paper presents a hybrid air quality modeling approach and its application in NEXUS in order to provide spatial and temporally varying exposure estimates and identification of the mobile source contribution to the total pollutant exposure. Model-based exposure metrics, associa...

  15. Modelling air quality in street canyons: a review

    NASA Astrophysics Data System (ADS)

    Vardoulakis, Sotiris; Fisher, Bernard E. A.; Pericleous, Koulis; Gonzalez-Flesca, Norbert

    High pollution levels have been often observed in urban street canyons due to the increased traffic emissions and reduced natural ventilation. Microscale dispersion models with different levels of complexity may be used to assess urban air quality and support decision-making for pollution control strategies and traffic planning. Mathematical models calculate pollutant concentrations by solving either analytically a simplified set of parametric equations or numerically a set of differential equations that describe in detail wind flow and pollutant dispersion. Street canyon models, which might also include simplified photochemistry and particle deposition-resuspension algorithms, are often nested within larger-scale urban dispersion codes. Reduced-scale physical models in wind tunnels may also be used for investigating atmospheric processes within urban canyons and validating mathematical models. A range of monitoring techniques is used to measure pollutant concentrations in urban streets. Point measurement methods (continuous monitoring, passive and active pre-concentration sampling, grab sampling) are available for gaseous pollutants. A number of sampling techniques (mainly based on filtration and impaction) can be used to obtain mass concentration, size distribution and chemical composition of particles. A combination of different sampling/monitoring techniques is often adopted in experimental studies. Relatively simple mathematical models have usually been used in association with field measurements to obtain and interpret time series of pollutant concentrations at a limited number of receptor locations in street canyons. On the other hand, advanced numerical codes have often been applied in combination with wind tunnel and/or field data to simulate small-scale dispersion within the urban canopy.

  16. Microwave landing system modeling with application to air traffic control

    NASA Technical Reports Server (NTRS)

    Poulose, M. M.

    1991-01-01

    Compared to the current instrument landing system, the microwave landing system (MLS), which is in the advanced stage of implementation, can potentially provide significant fuel and time savings as well as more flexibility in approach and landing functions. However, the expanded coverage and increased accuracy requirements of the MLS make it more susceptible to the features of the site in which it is located. An analytical approach is presented for evaluating the multipath effects of scatterers that are commonly found in airport environments. The approach combines a multiplane model with a ray-tracing technique and a formulation for estimating the electromagnetic fields caused by the antenna array in the presence of scatterers. The model is applied to several airport scenarios. The reduced computational burden enables the scattering effects on MLS position information to be evaluated in near real time. Evaluation in near real time would permit the incorporation of the modeling scheme into air traffic control automation; it would adaptively delineate zones of reduced accuracy within the MLS coverage volume, and help establish safe approach and takeoff trajectories in the presence of uneven terrain and other scatterers.

  17. Comparisons of Air Radiation Model with Shock Tube Measurements

    NASA Technical Reports Server (NTRS)

    Bose, Deepak; McCorkle, Evan; Bogdanoff, David W.; Allen, Gary A., Jr.

    2009-01-01

    This paper presents an assessment of the predictive capability of shock layer radiation model appropriate for NASA s Orion Crew Exploration Vehicle lunar return entry. A detailed set of spectrally resolved radiation intensity comparisons are made with recently conducted tests in the Electric Arc Shock Tube (EAST) facility at NASA Ames Research Center. The spectral range spanned from vacuum ultraviolet wavelength of 115 nm to infrared wavelength of 1400 nm. The analysis is done for 9.5-10.5 km/s shock passing through room temperature synthetic air at 0.2, 0.3 and 0.7 Torr. The comparisons between model and measurements show discrepancies in the level of background continuum radiation and intensities of atomic lines. Impurities in the EAST facility in the form of carbon bearing species are also modeled to estimate the level of contaminants and their impact on the comparisons. The discrepancies, although large is some cases, exhibit order and consistency. A set of tests and analyses improvements are proposed as forward work plan in order to confirm or reject various proposed reasons for the observed discrepancies.

  18. Modeling exposure close to air pollution sources in naturally ventilated residences: association of turbulent diffusion coefficient with air change rate.

    PubMed

    Cheng, Kai-Chung; Acevedo-Bolton, Viviana; Jiang, Ruo-Ting; Klepeis, Neil E; Ott, Wayne R; Fringer, Oliver B; Hildemann, Lynn M

    2011-05-01

    For modeling exposure close to an indoor air pollution source, an isotropic turbulent diffusion coefficient is used to represent the average spread of emissions. However, its magnitude indoors has been difficult to assess experimentally due to limitations in the number of monitors available. We used 30-37 real-time monitors to simultaneously measure CO at different angles and distances from a continuous indoor point source. For 11 experiments involving two houses, with natural ventilation conditions ranging from <0.2 to >5 air changes per h, an eddy diffusion model was used to estimate the turbulent diffusion coefficients, which ranged from 0.001 to 0.013 m² s⁻¹. The model reproduced observed concentrations with reasonable accuracy over radial distances of 0.25-5.0 m. The air change rate, as measured using a SF₆ tracer gas release, showed a significant positive linear correlation with the air mixing rate, defined as the turbulent diffusion coefficient divided by a squared length scale representing the room size. The ability to estimate the indoor turbulent diffusion coefficient using two readily measurable parameters (air change rate and room dimensions) is useful for accurately modeling exposures in close proximity to an indoor pollution source.

  19. Rigid-plug elastic-water model for transient pipe flow with entrapped air pocket

    SciTech Connect

    Zhou, Ling; Liu, Prof. Deyou; Karney, Professor Byran W.; Zhang, Qin Fen; OU, CHANGQI

    2011-01-01

    Pressure transients in a rapidly filling pipe with an entrapped air pocket are investigated analytically. A rigid-plug elastic water model is developed by applying elastic water hammer to the majority of the water column while applying rigid water analysis to a small portion near the air-water interface, which avoids effectively the interpolation error of previous approaches. Moreover, another two simplified models are introduced respectively based on constant water length and by neglecting water elasticity. Verification of the three models is confirmed by experimental results. Calculations show that the simplification of constant water length is feasible for small air pockets. The complete rigid water model is appropriate for cases with large initial air volume. The rigid-plug elastic model can predict all the essential features for the entire range of initial air fraction considered in this study, and it is the effective model for analysis of pressure transients of entrapped air.

  20. CMAQ MODELING FOR AIR TOXICS AT FINE SCALES: A PROTOTYPE STUDY

    EPA Science Inventory

    Toxic air pollutants (TAPs) or hazardous air pollutants (HAPs) exhibit considerable spatial and temporal variability across urban areas. Therefore, the ability of chemical transport models (CTMs), e.g. Community Multi-scale Air Quality (CMAQ), to reproduce the spatial and tempor...

  1. 76 FR 23749 - Intelligent Mail Package Barcode (IMpb) Implementation for Commercial Parcels

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-04-28

    ... 111 Intelligent Mail Package Barcode (IMpb) Implementation for Commercial Parcels AGENCY: Postal... currently enhancing its operational capability to allow for the scanning of Intelligent Mail package barcodes (IMpb) and other extra services barcodes via automated processing equipment and Intelligent...

  2. 133. PARCEL HANDLING SPACE OF POST OFFICE BUILDING, LEVEL 72.5, ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    133. PARCEL HANDLING SPACE OF POST OFFICE BUILDING, LEVEL 72.5, NORTH OF TRUCKING PASSAGE MAIL TRANSPORT AREA, VIEW TO NORTHWEST - Terminal Tower Building, Cleveland Union Terminal, 50 Public Square, Cleveland, Cuyahoga County, OH

  3. Connectivity-based parcellation of the human frontal polar cortex.

    PubMed

    Moayedi, Massieh; Salomons, Tim V; Dunlop, Katharine A M; Downar, Jonathan; Davis, Karen D

    2015-09-01

    The frontal pole corresponds to Brodmann area (BA) 10, the largest single architectonic area in the human frontal lobe. Generally, BA10 is thought to contain two or three subregions that subserve broad functions such as multitasking, social cognition, attention, and episodic memory. However, there is a substantial debate about the functional and structural heterogeneity of this large frontal region. Previous connectivity-based parcellation studies have identified two or three subregions in the human frontal pole. Here, we used diffusion tensor imaging to assess structural connectivity of BA10 in 35 healthy subjects and delineated subregions based on this connectivity. This allowed us to determine the correspondence of structurally based subregions with the scheme previously defined functionally. Three subregions could be defined in each subject. However, these three subregions were not spatially consistent between subjects. Therefore, we accepted a solution with two subregions that encompassed the lateral and medial frontal pole. We then examined resting-state functional connectivity of the two subregions and found significant differences between their connectivities. The medial cluster was connected to nodes of the default-mode network, which is implicated in internally focused, self-related thought, and social cognition. The lateral cluster was connected to nodes of the executive control network, associated with directed attention and working memory. These findings support the concept that there are two major anatomical subregions of the frontal pole related to differences in functional connectivity.

  4. Intracellular parcel service: current issues in intracellular membrane trafficking.

    PubMed

    Herrmann, Johannes M; Spang, Anne

    2015-01-01

    Eukaryotic cells contain a multitude of membrane structures that are connected through a highly dynamic and complex exchange of their constituents. The vibrant instability of these structures challenges the classical view of defined, static compartments that are connected by different types of vesicles. Despite this astonishing complexity, proteins and lipids are accurately transported into the different intracellular membrane systems. Over the past few decades many factors have been identified that either mediate or regulate intracellular membrane trafficking. Like in a modern parcel sorting system of a logistics center, the cargo typically passes through several sequential sorting stations until it finally reaches the location that is specified by its individual address label. While each membrane system employs specific sets of factors, the transport processes typically operate on common principles. With the advent of genome- and proteome-wide screens, the availability of mutant collections, exciting new developments in microscope technology and sophisticated methods to study their dynamics, the future promises a broad and comprehensive picture of the processes by which eukaryotic cells sort their proteins.

  5. Tractography-based Parcellation of the Human Middle Temporal Gyrus

    PubMed Central

    Xu, Jinping; Wang, Jiaojian; Fan, Lingzhong; Li, Hai; Zhang, Wen; Hu, Qingmao; Jiang, Tianzi

    2015-01-01

    The middle temporal gyrus (MTG) participates in a variety of functions, suggesting the existence of distinct functional subregions. In order to further delineate the functions of this brain area, we parcellated the MTG based on its distinct anatomical connectivity profiles and identified four distinct subregions, including the anterior (aMTG), middle (mMTG), posterior (pMTG), and sulcus (sMTG). Both the anatomical connectivity patterns and the resting-state functional connectivity patterns revealed distinct connectivity profiles for each subregion. The aMTG was primarily involved in the default mode network, sound recognition, and semantic retrieval. The mMTG was predominantly involved in the semantic memory and semantic control networks. The pMTG seems to be a part of the traditional sensory language area. The sMTG appears to be associated with decoding gaze direction and intelligible speech. Interestingly, the functional connectivity with Brodmann’s Area (BA) 40, BA 44, and BA 45 gradually increased from the anterior to the posterior MTG, a finding which indicated functional topographical organization as well as implying that language processing is functionally segregated in the MTG. These proposed subdivisions of the MTG and its functions contribute to understanding the complex functions of the MTG at the subregional level. PMID:26689815

  6. Calculation of Per Parcel Probability for Dud Bombs in Germany

    NASA Astrophysics Data System (ADS)

    Tavakkoli Sabour, S. M.; Agarius, J.; Sadidi, J.

    2014-10-01

    Unexploded aerial Bombs, also known as duds or unfused bombs, of the bombardments in the past wars remain explosive for decades after the war under the earth's surface threatening the civil activities especially if dredging works are involved. Interpretation of the aerial photos taken shortly after bombardments has been proven to be useful for finding the duds. Unfortunately, the reliability of this method is limited by some factors. The chance of finding a dud on an aerial photo depends strongly on the photography system, the size of the bomb and the landcover. On the other hand, exploded bombs are considerably better detectable on aerial photos and confidently represent the extent and density of a bombardment. Considering an empirical quota of unfused bombs, the expected number of duds can be calculated by the number of exploded bombs. This can help to have a better calculation of cost-risk ratio and to classify the areas for clearance. This article is about a method for calculation of a per parcel probability of dud bombs according to the distribution and density of exploded bombs. No similar work has been reported in this field by other authors.

  7. Development and Evaluation of Land-Use Regression Models Using Modeled Air Quality Concentrations

    EPA Science Inventory

    Abstract Land-use regression (LUR) models have emerged as a preferred methodology for estimating individual exposure to ambient air pollution in epidemiologic studies in absence of subject-specific measurements. Although there is a growing literature focused on LUR evaluation, fu...

  8. Dynamic Model of the BIO-Plex Air Revitalization System

    NASA Technical Reports Server (NTRS)

    Finn, Cory; Meyers, Karen; Duffield, Bruce; Luna, Bernadette (Technical Monitor)

    2000-01-01

    The BIO-Plex facility will need to support a variety of life support system designs and operation strategies. These systems will be tested and evaluated in the BIO-Plex facility. An important goal of the life support program is to identify designs that best meet all size and performance constraints for a variety of possible future missions. Integrated human testing is a necessary step in reaching this goal. System modeling and analysis will also play an important role in this endeavor. Currently, simulation studies are being used to estimate air revitalization buffer and storage requirements in order to develop the infrastructure requirements of the BIO-Plex facility. Simulation studies are also being used to verify that the envisioned operation strategy will be able to meet all performance criteria. In this paper, a simulation study is presented for a nominal BIO-Plex scenario with a high-level of crop growth. A general description of the dynamic mass flow model is provided, along with some simulation results. The paper also discusses sizing and operations issues and describes plans for future simulation studies.

  9. APPLICATION OF FINE SCALE AIR TOXICS MODELING WITH CMAQ TO HAPEM5

    EPA Science Inventory

    This paper provides a preliminary demonstration of the EPA neighborhood scale modeling paradigm for air toxics by linking concentration from the Community Multiscale Air Quality (CMAQ) modeling system to the fifth version of the Hazardous Pollutant Exposure Model (HAPEM5). For t...

  10. FINE SCALE AIR QUALITY MODELING USING DISPERSION AND CMAQ MODELING APPROACHES: AN EXAMPLE APPLICATION IN WILMINGTON, DE

    EPA Science Inventory

    Characterization of spatial variability of air pollutants in an urban setting at fine scales is critical for improved air toxics exposure assessments, for model evaluation studies and also for air quality regulatory applications. For this study, we investigate an approach that su...

  11. Improving reliability of subject-level resting-state fMRI parcellation with shrinkage estimators.

    PubMed

    Mejia, Amanda F; Nebel, Mary Beth; Shou, Haochang; Crainiceanu, Ciprian M; Pekar, James J; Mostofsky, Stewart; Caffo, Brian; Lindquist, Martin A

    2015-05-15

    A recent interest in resting state functional magnetic resonance imaging (rsfMRI) lies in subdividing the human brain into anatomically and functionally distinct regions of interest. For example, brain parcellation is often a necessary step for defining the network nodes used in connectivity studies. While inference has traditionally been performed on group-level data, there is a growing interest in parcellating single subject data. However, this is difficult due to the inherent low signal-to-noise ratio of rsfMRI data, combined with typically short scan lengths. A large number of brain parcellation approaches employ clustering, which begins with a measure of similarity or distance between voxels. The goal of this work is to improve the reproducibility of single-subject parcellation using shrinkage-based estimators of such measures, allowing the noisy subject-specific estimator to "borrow strength" in a principled manner from a larger population of subjects. We present several empirical Bayes shrinkage estimators and outline methods for shrinkage when multiple scans are not available for each subject. We perform shrinkage on raw inter-voxel correlation estimates and use both raw and shrinkage estimates to produce parcellations by performing clustering on the voxels. While we employ a standard spectral clustering approach, our proposed method is agnostic to the choice of clustering method and can be used as a pre-processing step for any clustering algorithm. Using two datasets - a simulated dataset where the true parcellation is known and is subject-specific and a test-retest dataset consisting of two 7-minute resting-state fMRI scans from 20 subjects - we show that parcellations produced from shrinkage correlation estimates have higher reliability and validity than those produced from raw correlation estimates. Application to test-retest data shows that using shrinkage estimators increases the reproducibility of subject-specific parcellations of the motor cortex by

  12. Improving Reliability of Subject-Level Resting-State fMRI Parcellation with Shrinkage Estimators

    PubMed Central

    Mejia, Amanda F.; Nebel, Mary Beth; Shou, Haochang; Crainiceanu, Ciprian M.; Pekar, James J.; Mostofsky, Stewart; Caffo, Brian; Lindquist, Martin A.

    2015-01-01

    A recent interest in resting state functional magnetic resonance imaging (rsfMRI) lies in subdividing the human brain into anatomically and functionally distinct regions of interest. For example, brain parcellation is often a necessary step for defining the network nodes used in connectivity studies. While inference has traditionally been performed on group-level data, there is a growing interest in parcellating single subject data. However, this is difficult due to the inherent low signal-to-noise ratio of rsfMRI data, combined with typically short scan lengths. A large number of brain parcellation approaches employ clustering, which begins with a measure of similarity or distance between voxels. The goal of this work is to improve the reproducibility of single-subject parcellation using shrinkage-based estimators of such measures, allowing the noisy subject-specific estimator to “borrow strength” in a principled manner from a larger population of subjects. We present several empirical Bayes shrinkage estimators and outline methods for shrinkage when multiple scans are not available for each subject. We perform shrinkage on raw inter-voxel correlation estimates and use both raw and shrinkage estimates to produce parcellations by performing clustering on the voxels. While we employ a standard spectral clustering approach, our proposed method is agnostic to the choice of clustering method and can be used as a pre-processing step for any clustering algorithm. Using two datasets – a simulated dataset where the true parcellation is known and is subject-specific and a test-retest dataset consisting of two 7-minute resting-state fMRI scans from 20 subjects – we show that parcellations produced from shrinkage correlation estimates have higher reliability and validity than those produced from raw correlation estimates. Application to test-retest data shows that using shrinkage estimators increases the reproducibility of subject-specific parcellations of the motor

  13. Improving reliability of subject-level resting-state fMRI parcellation with shrinkage estimators.

    PubMed

    Mejia, Amanda F; Nebel, Mary Beth; Shou, Haochang; Crainiceanu, Ciprian M; Pekar, James J; Mostofsky, Stewart; Caffo, Brian; Lindquist, Martin A

    2015-05-15

    A recent interest in resting state functional magnetic resonance imaging (rsfMRI) lies in subdividing the human brain into anatomically and functionally distinct regions of interest. For example, brain parcellation is often a necessary step for defining the network nodes used in connectivity studies. While inference has traditionally been performed on group-level data, there is a growing interest in parcellating single subject data. However, this is difficult due to the inherent low signal-to-noise ratio of rsfMRI data, combined with typically short scan lengths. A large number of brain parcellation approaches employ clustering, which begins with a measure of similarity or distance between voxels. The goal of this work is to improve the reproducibility of single-subject parcellation using shrinkage-based estimators of such measures, allowing the noisy subject-specific estimator to "borrow strength" in a principled manner from a larger population of subjects. We present several empirical Bayes shrinkage estimators and outline methods for shrinkage when multiple scans are not available for each subject. We perform shrinkage on raw inter-voxel correlation estimates and use both raw and shrinkage estimates to produce parcellations by performing clustering on the voxels. While we employ a standard spectral clustering approach, our proposed method is agnostic to the choice of clustering method and can be used as a pre-processing step for any clustering algorithm. Using two datasets - a simulated dataset where the true parcellation is known and is subject-specific and a test-retest dataset consisting of two 7-minute resting-state fMRI scans from 20 subjects - we show that parcellations produced from shrinkage correlation estimates have higher reliability and validity than those produced from raw correlation estimates. Application to test-retest data shows that using shrinkage estimators increases the reproducibility of subject-specific parcellations of the motor cortex by

  14. A Flexible Spatio-Temporal Model for Air Pollution with Spatial and Spatio-Temporal Covariates

    PubMed Central

    Lindström, Johan; Szpiro, Adam A; Sampson, Paul D; Oron, Assaf P; Richards, Mark; Larson, Tim V; Sheppard, Lianne

    2013-01-01

    The development of models that provide accurate spatio-temporal predictions of ambient air pollution at small spatial scales is of great importance for the assessment of potential health effects of air pollution. Here we present a spatio-temporal framework that predicts ambient air pollution by combining data from several different monitoring networks and deterministic air pollution model(s) with geographic information system (GIS) covariates. The model presented in this paper has been implemented in an R package, SpatioTemporal, available on CRAN. The model is used by the EPA funded Multi-Ethnic Study of Atherosclerosis and Air Pollution (MESA Air) to produce estimates of ambient air pollution; MESA Air uses the estimates to investigate the relationship between chronic exposure to air pollution and cardiovascular disease. In this paper we use the model to predict long-term average concentrations of NOx in the Los Angeles area during a ten year period. Predictions are based on measurements from the EPA Air Quality System, MESA Air specific monitoring, and output from a source dispersion model for traffic related air pollution (Caline3QHCR). Accuracy in predicting long-term average concentrations is evaluated using an elaborate cross-validation setup that accounts for a sparse spatio-temporal sampling pattern in the data, and adjusts for temporal effects. The predictive ability of the model is good with cross-validated R2 of approximately 0.7 at subject sites. Replacing four geographic covariate indicators of traffic density with the Caline3QHCR dispersion model output resulted in very similar prediction accuracy from a more parsimonious and more interpretable model. Adding traffic-related geographic covariates to the model that included Caline3QHCR did not further improve the prediction accuracy. PMID:25264424

  15. Trajectory modeling of emissions from lower stratospheric aircraft

    NASA Astrophysics Data System (ADS)

    Sparling, Lynn C.; Schoeberl, Mark R.; Douglass, Anne R.; Weaver, Clark J.; Newman, Paul A.; Lait, Leslie R.

    1995-01-01

    A series of isentropic trajectory calculations has been performed for emissions by stratospheric aircraft moving across the northern midlatitude oceanic flight corridors. Emission of exhaust is simulated by the daily initialization of air parcels along a flight path on the 500 K isentropic surface. Parcels are tracked during the first three weeks of each January from 1980 to 1994 in order to determine the interannual variability in the spatial distribution of the exhaust and the likelihood of exposure to cold temperatures. Few parcels emitted along these flight paths at this time of year were found to have experienced nitric acid trihydrate (NAT) formation temperatures, except for the particularly cold Januarys 1986, 1987, and 1992. We also find that large zonal fluctuations in the distribution of the emissions are typical for this time of year and are strongly dependent on flight path. An extended 6-month (January-June) run in which parcels were released daily along the New York-London route shows that emissions in the flight corridor increase at a time-averaged rate which is nearly twice the rate at which the zonal average increases. In addition, local fluctuations of pollutant density can be several times higher than the zonal average and can persist for several weeks. A study of seasonal variability also shows a rapid buildup of emissions during the summer months. These elevated emission levels must be considered in the interpretation of environmental impact assessments based on two-dimensional transport models.

  16. Trajectory modeling of emissions from lower stratospheric aircraft

    SciTech Connect

    Sparling, L.C.; Lait, L.R.; Weaver, C.J.

    1995-01-20

    A series of isentropic trajectory calculations has been performed for emissions by stratospheric aircraft moving across the northern midlatitude oceanic flight corridors. Emission of exhaust is simulated by the daily initialization of air parcels along a flight path on the 500 K isentropic surface. Parcels are tracked during the first three weeks of each January from 1980 to 1994 in order to determine the interannual variability in the spatial distribution of the exhaust and the liklihood of exposure to cold temperatures. Few parcels emitted along these flights paths at this time of year were found to have experienced nitric acid trihydrate (NAT) formation temperatures, except for the particularly cold Januarys 1986, 1987, and 1992. The authors also find that large zonal fluctuations in the distribution of the emissions are typical for this time of year and are strongly dependent on flight path. An extended 6-month (January-June) run in which parcels were released daily along the New York-London route shows that emissions in the flight corridor increase at a time-averaged rate which is nearly twice the rate at which the zonal average increases. In addition, local fluctuations of pollutant density can be several times higher than the zonal average and can persist for several weeks. A study of seasonal variability also shows a rapid buildup of emissions during the summer months. These elevated emission levels must be considered in the interpretation of environmental impact assessments based on two-dimensional transport models. 31 refs., 16 figs.

  17. FVCOM model estimate of the location of Air France 447

    NASA Astrophysics Data System (ADS)

    Chen, Changsheng; Limeburner, Richard; Gao, Guoping; Xu, Qichun; Qi, Jianhua; Xue, Pengfei; Lai, Zhigang; Lin, Huichan; Beardsley, Robert; Owens, Breck; Carlson, Barry

    2012-06-01

    On June 1, 2009, Air France AF447 disappeared in the Equatorial Atlantic Ocean en route from Rio de Janeiro, Brazil, to Paris, France. On June 6-19, 2009, bodies and debris from the aircraft were recovered floating in the equatorial ocean. This paper describes efforts on using the global-local nested finite volume community ocean model (FVCOM) to model reversely the tracks of bodies and debris back to the time of the crash and to help searchers locate the cockpit voice and flight data recorders and learn why this tragic accident occurred. To validate the reliability and reality of FVCOM, eight surface drifters were deployed by the French Bureau d'Enquêtes et d'Analyses pour la sécurité de l'aviation civile (BEA) near the last known position in early June 2010 for a period of 3 weeks. These drifter data were used to optimize the spatial and temporal correlation scales of the adaptive sampling data assimilation method of FVCOM. Applying an optimized FVCOM system to assimilate all available drifter- and float-tracking-derived currents in May-June 2009 under three different wind conditions, we reproduced the June 2009 current fields in the area near the LKP and used these fields to reversely track bodies and debris from locations where they were found to the time when the crash occurred. Possible locations for the crashed plane were suggested based on our model results and were made available to the French investigators and the Woods Hole Oceanographic Institution REMUS autonomous underwater vehicle Operations Group who successfully located the aircraft debris field in April 2011 on the seafloor at a depth of 3,900 m.

  18. Modelling future impacts of air pollution using the multi-scale UK Integrated Assessment Model (UKIAM).

    PubMed

    Oxley, Tim; Dore, Anthony J; ApSimon, Helen; Hall, Jane; Kryza, Maciej

    2013-11-01

    Integrated assessment modelling has evolved to support policy development in relation to air pollutants and greenhouse gases by providing integrated simulation tools able to produce quick and realistic representations of emission scenarios and their environmental impacts without the need to re-run complex atmospheric dispersion models. The UK Integrated Assessment Model (UKIAM) has been developed to investigate strategies for reducing UK emissions by bringing together information on projected UK emissions of SO2, NOx, NH3, PM10 and PM2.5, atmospheric dispersion, criteria for protection of ecosystems, urban air quality and human health, and data on potential abatement measures to reduce emissions, which may subsequently be linked to associated analyses of costs and benefits. We describe the multi-scale model structure ranging from continental to roadside, UK emission sources, atmospheric dispersion of emissions, implementation of abatement measures, integration with European-scale modelling, and environmental impacts. The model generates outputs from a national perspective which are used to evaluate alternative strategies in relation to emissions, deposition patterns, air quality metrics and ecosystem critical load exceedance. We present a selection of scenarios in relation to the 2020 Business-As-Usual projections and identify potential further reductions beyond those currently being planned.

  19. Interfacing air pathway models with other media models for impact assessment

    SciTech Connect

    Drake, R.L.

    1980-10-01

    The assessment of the impacts/effects of a coal conversion industry on human health, ecological systems, property and aesthetics requires knowledge about effluent and fugitive emissions, dispersion of pollutants in abiotic media, chemical and physical transformations of pollutants during transport, and pollutant fate passing through biotic pathways. Some of the environmental impacts that result from coal conversion facility effluents are subtle, acute, subacute or chronic effects in humans and other ecosystem members, acute or chronic damage of materials and property, odors, impaired atmospheric visibility, and impacts on local, regional and global weather and climate. This great variety of impacts and effects places great demands on the abiotic and biotic numerical simulators (modelers) in terms of time and space scales, transformation rates, and system structure. This paper primarily addresses the demands placed on the atmospheric analyst. The paper considers the important air pathway processes, the interfacing of air pathway models with other media models, and the classes of air pathway models currently available. In addition, a strong plea is made for interaction and communication between all modeling groups to promote efficient construction of intermedia models that truly interface across pathway boundaries.

  20. Modeling near-road air quality using a computational fluid dynamics model, CFD-VIT-RIT.

    PubMed

    Wang, Y Jason; Zhang, K Max

    2009-10-15

    It is well recognized that dilution is an important mechanism governing the near-road air pollutant concentrations. In this paper, we aim to advance our understanding of turbulent mixing mechanisms on and near roadways using computation fluid dynamics. Turbulent mixing mechanisms can be classified into three categories according to their origins: vehicle-induced turbulence (VIT), road-induced turbulence (RIT), and atmospheric boundary layer turbulence. RIT includes the turbulence generated by road embankment, road surface thermal effects, and roadside structures. Both VIT and RIT are affected by the roadway designs. We incorporate the detailed treatment of VIT and RIT into the CFD (namely CFD-VIT-RIT) and apply the model in simulating the spatial gradients of carbon monoxide near two major highways with different traffic mix and roadway configurations. The modeling results are compared to the field measurements and those from CALINE4 and CFD without considering VIT and RIT. We demonstrate that the incorporation of VIT and RIT considerably improves the modeling predictions, especially on vertical gradients and seasonal variations of carbon monoxide. Our study implies that roadway design can significantly influence the near-road air pollution. Thus we recommend that mitigating near-road air pollution through roadway designs be considered in the air quality and transportation management In addition, thanks to the rigorous representation of turbulent mixing mechanisms, CFD-VIT-RIT can become valuable tools in the roadway designs process.

  1. The Atlanta Urban Heat Island Mitigation and Air Quality Modeling Project: How High-Resoution Remote Sensing Data Can Improve Air Quality Models

    NASA Technical Reports Server (NTRS)

    Quattrochi, Dale A.; Estes, Maurice G., Jr.; Crosson, William L.; Khan, Maudood N.

    2006-01-01

    The Atlanta Urban Heat Island and Air Quality Project had its genesis in Project ATLANTA (ATlanta Land use Analysis: Temperature and Air quality) that began in 1996. Project ATLANTA examined how high-spatial resolution thermal remote sensing data could be used to derive better measurements of the Urban Heat Island effect over Atlanta. We have explored how these thermal remote sensing, as well as other imaged datasets, can be used to better characterize the urban landscape for improved air quality modeling over the Atlanta area. For the air quality modeling project, the National Land Cover Dataset and the local scale Landpro99 dataset at 30m spatial resolutions have been used to derive land use/land cover characteristics for input into the MM5 mesoscale meteorological model that is one of the foundations for the Community Multiscale Air Quality (CMAQ) model to assess how these data can improve output from CMAQ. Additionally, land use changes to 2030 have been predicted using a Spatial Growth Model (SGM). SGM simulates growth around a region using population, employment and travel demand forecasts. Air quality modeling simulations were conducted using both current and future land cover. Meteorological modeling simulations indicate a 0.5 C increase in daily maximum air temperatures by 2030. Air quality modeling simulations show substantial differences in relative contributions of individual atmospheric pollutant constituents as a result of land cover change. Enhanced boundary layer mixing over the city tends to offset the increase in ozone concentration expected due to higher surface temperatures as a result of urbanization.

  2. Air Quality Modeling in Support of the Near-road EXposures and effects of Urban air pollutants Study (NEXUS)

    EPA Science Inventory

    The paper presents the results of the model applications to estimate exposure metrics in support of an epidemiologic study in Detroit, Michigan. The Near-road Exposures to Urban air pollutant Study (NEXUS) design includes determining if children in Detroit, MI with asthma living ...

  3. Comparison of stationary and personal air sampling with an air dispersion model for children’s ambient exposure to manganese

    EPA Science Inventory

    Manganese (Mn) is ubiquitous in the environment and essential for normal growth and development, yet excessive exposure can lead to impairments in neurological function. This study modeled ambient Mn concentrations as an alternative to stationary and personal air sampling to asse...

  4. Existing air sparging model and literature review for the development of an air sparging optimization decision tool

    SciTech Connect

    1995-08-01

    The objectives of this Report are two-fold: (1) to provide overviews of the state-of-the-art and state-of-the-practice with respect to air sparging technology, air sparging models and related or augmentation technologies (e.g., soil vapor extraction); and (2) to provide the basis for the development of the conceptual Decision Tool. The Project Team conducted an exhaustive review of available literature. The complete listing of the documents, numbering several hundred and reviewed as a part of this task, is included in Appendix A. Even with the large amount of material written regarding the development and application of air sparging, there still are significant gaps in the technical community`s understanding of the remediation technology. The results of the literature review are provided in Section 2. In Section 3, an overview of seventeen conceptual, theoretical, mathematical and empirical models is presented. Detailed descriptions of each of the models reviewed is provided in Appendix B. Included in Appendix D is a copy of the questionnaire used to compile information about the models. The remaining sections of the document reflect the analysis and synthesis of the information gleaned during the literature and model reviews. The results of these efforts provide the basis for development of the decision tree and conceptual decision tool for determining applicability and optimization of air sparging. The preliminary decision tree and accompanying information provided in Section 6 describe a three-tiered approach for determining air sparging applicability: comparison with established scenarios; calculation of conceptual design parameters; and the conducting of pilot-scale studies to confirm applicability. The final two sections of this document provide listings of the key success factors which will be used for evaluating the utility of the Decision Tool and descriptions of potential applications for Decision Tool use.

  5. Diagnostic Analysis of Ozone Concentrations Simulated by Two Regional-Scale Air Quality Models

    EPA Science Inventory

    Since the Community Multiscale Air Quality modeling system (CMAQ) and the Weather Research and Forecasting with Chemistry model (WRF/Chem) use different approaches to simulate the interaction of meteorology and chemistry, this study compares the CMAQ and WRF/Chem air quality simu...

  6. The AQMEII Two-Continent Regional Air Quality Model Evaluation Study: Fueling Ideas with Unprecedented Data

    EPA Science Inventory

    Although strong collaborations in the air pollution field have existed among the North American (NA) and European (EU) countries over the past five decades, regional-scale air quality model developments and model performance evaluations have been carried out independently unlike ...

  7. Dynamic Evaluation of a Regional Air Quality Model: Assessing the Emissions-Induced Weekly Ozone Cycle

    EPA Science Inventory

    Air quality models are used to predict changes in pollutant concentrations resulting from envisioned emission control policies. Recognizing the need to assess the credibility of air quality models in a policy-relevant context, we perform a dynamic evaluation of the community Mult...

  8. Air Quality Model Evaluation International Initiative (AQMEII) - Utrecht, Netherlands The May 8, 2012

    EPA Science Inventory

    The 4th workshop of the Air Quality Model Evaluation International Initiative (AQMEII) was held on May 8 in Utrecht, The Netherlands, in conjunction with the NATO/SPS International Technical Meeting on Air Pollution Modeling and Its Application. AQMEII was launched in 2009 as a l...

  9. SIMULATION OF AEROSOL DYNAMICS: A COMPARATIVE REVIEW OF ALGORITHMS USED IN AIR QUALITY MODELS

    EPA Science Inventory

    A comparative review of algorithms currently used in air quality models to simulate aerosol dynamics is presented. This review addresses coagulation, condensational growth, nucleation, and gas/particle mass transfer. Two major approaches are used in air quality models to repres...

  10. Dynamic Evaluation of Long-Term Air Quality Model Simulations Over the Northeastern U.S.

    EPA Science Inventory

    Dynamic model evaluation assesses a modeling system's ability to reproduce changes in air quality induced by changes in meteorology and/or emissions. In this paper, we illustrate various approaches to dynamic mode evaluation utilizing 18 years of air quality simulations perform...

  11. Urban Landscape Characterization Using Remote Sensing Data For Input into Air Quality Modeling

    NASA Technical Reports Server (NTRS)

    Quattrochi, Dale A.; Estes, Maurice G., Jr.; Crosson, William; Khan, Maudood

    2005-01-01

    The urban landscape is inherently complex and this complexity is not adequately captured in air quality models that are used to assess whether urban areas are in attainment of EPA air quality standards, particularly for ground level ozone. This inadequacy of air quality models to sufficiently respond to the heterogeneous nature of the urban landscape can impact how well these models predict ozone pollutant levels over metropolitan areas and ultimately, whether cities exceed EPA ozone air quality standards. We are exploring the utility of high-resolution remote sensing data and urban growth projections as improved inputs to meteorological and air quality models focusing on the Atlanta, Georgia metropolitan area as a case study. The National Land Cover Dataset at 30m resolution is being used as the land use/land cover input and aggregated to the 4km scale for the MM5 mesoscale meteorological model and the Community Multiscale Air Quality (CMAQ) modeling schemes. Use of these data have been found to better characterize low density/suburban development as compared with USGS 1 km land use/land cover data that have traditionally been used in modeling. Air quality prediction for future scenarios to 2030 is being facilitated by land use projections using a spatial growth model. Land use projections were developed using the 2030 Regional Transportation Plan developed by the Atlanta Regional Commission. This allows the State Environmental Protection agency to evaluate how these transportation plans will affect future air quality.

  12. Modelling relationships between lichen bioindicators, air quality and climate on a national scale: results from the UK OPAL air survey.

    PubMed

    Seed, Lindsay; Wolseley, Pat; Gosling, Laura; Davies, Linda; Power, Sally A

    2013-11-01

    Air pollution has many negative effects on the natural environment, from changes in plant growth patterns to loss of ecosystem function. This study uses citizen science to investigate national-scale patterns in the distribution and abundance of selected lichen species on tree trunks and branches, and to relate these to air pollution and climate. Volunteers collected data for nine lichen indicators on 19,334 deciduous trees. Submitted data provided information on species-level patterns, and were used to derive composite lichen indices. Multiple linear regression and ANCOVA were used to model the relationships between lichen response variables on Quercus spp. and pollution, climate and location. The study demonstrated significant relationships between patterns in indicator lichens and levels of N- and S-containing pollutants on trunks and twigs. The derived lichen indices show great potential as a tool to provide information on local, site-specific levels of air quality. PMID:23992684

  13. High-resolution modelling of health impacts from air pollution using the integrated model system EVA

    NASA Astrophysics Data System (ADS)

    Brandt, Jørgen; Andersen, Mikael S.; Bønløkke, Jakob; Christensen, Jesper H.; Geels, Camilla; Hansen, Kaj M.; Jensen, Steen S.; Ketzel, Matthias; Plejdrup, Marlene S.; Sigsgaard, Torben; Silver, Jeremy D.

    2014-05-01

    A high-resolution assessment of health impacts from air pollution and related external cost has been conducted for Denmark using the integrated EVA model system. The EVA system has been further developed by implementing an air quality model with a 1 km x 1 km resolution covering the whole of Denmark. New developments of the integrated model system will be presented as well as results for health impacts and related external costs over several decades. Furthermore, the sensitivity of health impacts to model resolution will be studied. We have developed an integrated model system EVA (Economic Valuation of Air pollution), based on the impact-pathway chain, to assess the health impacts and health-related economic externalities of air pollution resulting from specific emission sources or sectors. The system is used to support policymaking with respect to emission control. In Brandt et al. (2013a; 2013b), the EVA system was used to assess the impacts in Europe and Denmark from the past, present and future total air pollution levels as well as the contribution from the major anthropogenic emission sectors. The EVA system was applied using the hemispheric chemistry-transport model, the Danish Eulerian Hemispheric Model (DEHM), with nesting capability for higher resolution over Europe (50 km x 50 km) and Northern Europe (16.7 km x 16.7 km). In this study an Urban Background Model (UBM) has been further developed to cover the whole of Denmark with a 1 km x 1 km resolution and the model has been implemented as a part of the integrated model system, EVA. The EVA system is based on the impact-pathway methodology. The site-specific emissions will result (via atmospheric transport and chemistry) in a concentration distribution, which together with detailed population data, are used to estimate the population-level exposure. Using exposure-response functions and economic valuations, the exposure is transformed into impacts on human health and related external costs. In this study

  14. Aircraft/Air Traffic Management Functional Analysis Model. Version 2.0; User's Guide

    NASA Technical Reports Server (NTRS)

    Etheridge, Melvin; Plugge, Joana; Retina, Nusrat

    1998-01-01

    The Aircraft/Air Traffic Management Functional Analysis Model, Version 2.0 (FAM 2.0), is a discrete event simulation model designed to support analysis of alternative concepts in air traffic management and control. FAM 2.0 was developed by the Logistics Management Institute (LMI) a National Aeronautics and Space Administration (NASA) contract. This document provides a guide for using the model in analysis. Those interested in making enhancements or modification to the model should consult the companion document, Aircraft/Air Traffic Management Functional Analysis Model, Version 2.0 Technical Description.

  15. MODELING POPULATION EXPOSURES TO OUTDOOR SOURCES OF HAZARDOUS AIR POLLUTANTS

    EPA Science Inventory

    Accurate assessment of human exposures is an important part of environmental health effects research. However, most air pollution epidemiology studies rely upon imperfect surrogates of personal exposures, such as information based on available central-site outdoor concentration ...

  16. Semi-Lagrangian Methods in Air Pollution Models.

    NASA Astrophysics Data System (ADS)

    Buus Hansen, A.; Kaas, E.; Christensen, J. H.; Brandt, J.

    2009-04-01

    Various semi-Lagrangian methods are tested for use in air pollution model- ing. The aim is to find a method fulfilling as many of the desirable properties by Rasch and Williamson (1990) and Machenhauer et al. (2008) as possi- ble. The focus is on accuracy, local mass conservation and computational efficiency. The methods tested are, first, classical semi-Lagrangian cubic interpola- tion, see e.g. Durran (1999), second, semi-Lagrangian cubic cascade inter- polation, by Nair et al. (2002), third, semi-Lagrangian cubic interpolation with the modified interpolation weights, by Kaas (2008), and last, semi- Lagrangian cubic interpolation with a locally mass conserving monotonic filter by Kaas and Nielsen (2008). Semi-Lagrangian (sL) interpolation is a classical method for atmospheric modeling, cascade interpolation is more efficient computationally, modified interpolation weights assure mass conservation and the locally mass con- serving monotonic filter imposes monotonicity. All schemes are tested with advection alone or with advection and chem- istry together under both typical rural and urban conditions using different temporal and spatial resolution. The methods are compared with a current state-of-the-art scheme presently used at the National Environmental Re- search Institute (NERI) in Denmark. The test cases are based either on the traditional slotted cylinder, see e.g. Zerroukat et al. (2002), or the rotating cone, see e.g. Molenkamp (1968) and Crowley (1968), where the schemes' ability to model both steep gradi- ents and slopes are challenged. The tests showed that the locally mass conserving monotonic filter im- proved the results significantly for some of the test cases, however, not for all. It was found that the semi-Lagrangian schemes, in almost every case, were not able to outperform the currently used ASD scheme used in DEHM, see e.g. Frohn et al. (2002). The present study is a part of the research of the Center for Energy, Envi- ronment and Health

  17. Hydrologic evaluation and water-supply considerations for five Paiute Indian land parcels, Millard, Sevier, and Iron counties, southwestern Utah

    USGS Publications Warehouse

    Price, Don; Stephens, D.W.; Conroy, L.S.

    1989-01-01

    The hydrologic resources in and adjacent to five parcels of land held in trust for the Paiute Indian Tribe of Utah were evaluated. The land, located in southwestern Utah, is generally arid and has had only limited use for grazing. The parcels are located near the towns of Cove Fort, Joseph, Koosharem, and Kanarraville. On the basis of available geohydrologic and hydrologic data, water of suitable quality is locally available in the areas of all parcels for domestic, stock, recreation, and limited irrigation use. Developing this water for use on the parcels would potentially involve obtaining water rights, drilling wells, and constructing diversion structures. Surface water apparently is the most favorable source of supply available for the Joseph parcel, and groundwater apparently is the most favorable source of supply available for the other parcels. (USGS)

  18. Development of Gridded Fields of Urban Canopy Parameters for Advanced Urban Meteorological and Air Quality Models

    EPA Science Inventory

    Urban dispersion and air quality simulation models applied at various horizontal scales require different levels of fidelity for specifying the characteristics of the underlying surfaces. As the modeling scales approach the neighborhood level (~1 km horizontal grid spacing), the...

  19. Framland parcels extraction from high-resolution remote sensing images based on the two-stage image classification

    NASA Astrophysics Data System (ADS)

    Liu, Guoying; Song, Xu; Lv, Jing

    2015-12-01

    It is difficult and boring for people to artificially extract farmland parcels from high resolution remote sensing images. Therefore, automatic methods are in the urgent need to release image interpreters from such a work as well as achieve accurate results. In the past years, although many researchers have made attempts to solve this problem by using different techniques and also produced some good results, they still cannot meet the demand of practical applications. In this paper, a farmland extraction method is proposed based on a new technique of two-stage image classification. The first stage aims at producing a map of farmland area by using the supervised iterative conditional mode (ICM), where a novel mixture posterior is proposed based on the tree-structured interpretation of certain complex landscapes, e.g., farmland and building area, and the Markov random field model (MRF) is also used to make use of spatial information between neighboring pixels. The second stage extracts the farmland parcels by using the Meanshift algorithm (MS) based on the hybrid of the original image and the texture image produced by the local binary pattern (LBP) method. We applied our method to a piece of aerial image in the urban area of Taizhou, China. The results show that the proposed method has an ability to produce more accurate results than the MS method.

  20. Assessment and prediction of air quality using fuzzy logic and autoregressive models

    NASA Astrophysics Data System (ADS)

    Carbajal-Hernández, José Juan; Sánchez-Fernández, Luis P.; Carrasco-Ochoa, Jesús A.; Martínez-Trinidad, José Fco.

    2012-12-01

    In recent years, artificial intelligence methods have been used for the treatment of environmental problems. This work, presents two models for assessment and prediction of air quality. First, we develop a new computational model for air quality assessment in order to evaluate toxic compounds that can harm sensitive people in urban areas, affecting their normal activities. In this model we propose to use a Sigma operator to statistically asses air quality parameters using their historical data information and determining their negative impact in air quality based on toxicity limits, frequency average and deviations of toxicological tests. We also introduce a fuzzy inference system to perform parameter classification using a reasoning process and integrating them in an air quality index describing the pollution levels in five stages: excellent, good, regular, bad and danger, respectively. The second model proposed in this work predicts air quality concentrations using an autoregressive model, providing a predicted air quality index based on the fuzzy inference system previously developed. Using data from Mexico City Atmospheric Monitoring System, we perform a comparison among air quality indices developed for environmental agencies and similar models. Our results show that our models are an appropriate tool for assessing site pollution and for providing guidance to improve contingency actions in urban areas.

  1. Smart tetroons for Lagrangian air-mass tracking during ACE 1

    NASA Astrophysics Data System (ADS)

    Businger, Steven; Johnson, Randy; Katzfey, Jack; Siems, Steven; Wang, Qing

    1999-05-01

    A series of "smart" tetroons was released from shipboard during the recent ACE 1 field experiment designed to monitor changes in the sulfur budget in a remote marine boundary layer (MBL) south of Tasmania, Australia. The smart tetroons were designed at NOAA Air Resources Laboratory Field Research Division to provide air parcel tracking information. The adjective smart here refers here to the fact that the buoyancy of the tetroons automatically adjusts through the action of a pump and valves when the tetroon travels vertically outside a range of pressures set prior to tetroon release. The smart tetroon design provides GPS location, barometric pressure, temperature, relative humidity, and tetroon status data via a transponder to the NCAR C-130 research aircraft flying in the vicinity of the tetroons. In this paper we will describe (1) the design and capability of the smart tetroons and their performance during the two Lagrangian experiments conducted during ACE 1, (2) the synoptic context of the Lagrangians, including the origin of the air parcels being tracked, and (3) the results of trajectory predictions derived from the National Center for Environmental Prediction (NCEP) Global Spectral Model (GSM) and Australia's Commonwealth Scientific and Industrial Research Organization (CSIRO) Division of Atmospheric Research (DAR) limited-area model.

  2. Local-Scale Air Quality Modeling in Support of Human Health and Exposure Research (Invited)

    NASA Astrophysics Data System (ADS)

    Isakov, V.

    2010-12-01

    Spatially- and temporally-sparse information on air quality is a key concern for air-pollution-related environmental health studies. Monitor networks are sparse in both space and time, are costly to maintain, and are often designed purposely to avoid detecting highly localized sources. Recent studies have shown that more narrowly defining the geographic domain of the study populations and improvements in the measured/estimated ambient concentrations can lead to stronger associations between air pollution and hospital admissions and mortality records. Traditionally, ambient air quality measurements have been used as a primary input to support human health and exposure research. However, there is increasing evidence that the current ambient monitoring network is not capturing sharp gradients in exposure due to the presence of high concentration levels near, for example, major roadways. Many air pollutants exhibit large concentration gradients near large emitters such as major roadways, factories, ports, etc. To overcome these limitations, researchers are now beginning to use air quality models to support air pollution exposure and health studies. There are many advantages to using air quality models over traditional approaches based on existing ambient measurements alone. First, models can provide spatially- and temporally-resolved concentrations as direct input to exposure and health studies and thus better defining the concentration levels for the population in the geographic domain. Air quality models have a long history of use in air pollution regulations, and supported by regulatory agencies and a large user community. Also, models can provide bidirectional linkages between sources of emissions and ambient concentrations, thus allowing exploration of various mitigation strategies to reduce risk to exposure. In order to provide best estimates of air concentrations to support human health and exposure studies, model estimates should consider local-scale features

  3. On the accuracy of the rate coefficients used in plasma fluid models for breakdown in air

    NASA Astrophysics Data System (ADS)

    Kourtzanidis, Konstantinos; Raja, Laxminarayan L.

    2016-07-01

    The electrical breakdown of air depends on the balance between creation and loss of charged particles. In fluid models, datasets of the rate coefficients used are obtained either from fits to experimental data or by solutions of the Boltzmann equation. Here, we study the accuracy of the commonly used models for ionization and attachment frequencies and their impact on the prediction of the breakdown threshold for air. We show that large errors can occur depending on the model and propose the most accurate dataset available for modeling of air breakdown phenomena.

  4. Modeling subcanopy incoming longwave radiation to seasonal snow using air and tree trunk temperatures

    NASA Astrophysics Data System (ADS)

    Webster, Clare; Rutter, Nick; Zahner, Franziska; Jonas, Tobias

    2016-02-01

    Data collected at three Swiss alpine forested sites over a combined 11 year period were used to evaluate the role of air temperature in modeling subcanopy incoming longwave radiation to the snow surface. Simulated subcanopy incoming longwave radiation is traditionally partitioned into that from the sky and that from the canopy, i.e., a two-part model. Initial uncertainties in predicting longwave radiation using the two-part model resulted from vertical differences in measured air temperature. Above-canopy (35 m) air temperatures were higher than those within (10 m) and below (2 m) canopy throughout four snow seasons (December-April), demonstrating how the forest canopy can act as a cold sink for air. Lowest model root-mean-square error (RMSE) was using above-canopy air temperature. Further investigation of modeling subcanopy longwave radiation using above-canopy air temperature showed underestimations, particularly during periods of high insolation. In order to explicitly account for canopy temperatures in modeling longwave radiation, the two-part model was improved by incorporating a measured trunk view component and trunk temperature. Trunk temperature measurements were up to 25°C higher than locally measured air temperatures. This three-part model reduced the RMSE by up to 7.7 W m-2 from the two-part air temperature model at all sensor positions across the 2014 snowmelt season and performed particularly well during periods of high insolation when errors from the two-part model were up to 40 W m-2. A parameterization predicting tree trunk temperatures using measured air temperature and incoming shortwave radiation demonstrate a simple method that can be applied to provide input to the three-part model across midlatitude coniferous forests.

  5. Geospatial Modeling of Asthma Population in Relation to Air Pollution

    NASA Technical Reports Server (NTRS)

    Kethireddy, Swatantra R.; Tchounwou, Paul B.; Young, John H.; Luvall, Jeffrey C.; Alhamdan, Mohammad

    2013-01-01

    Current observations indicate that asthma is growing every year in the United States, specific reasons for this are not well understood. This study stems from an ongoing research effort to investigate the spatio-temporal behavior of asthma and its relatedness to air pollution. The association between environmental variables such as air quality and asthma related health issues over Mississippi State are investigated using Geographic Information Systems (GIS) tools and applications. Health data concerning asthma obtained from Mississippi State Department of Health (MSDH) for 9-year period of 2003-2011, and data of air pollutant concentrations (PM2.5) collected from USEPA web resources, and are analyzed geospatially to establish the impacts of air quality on human health specifically related to asthma. Disease mapping using geospatial techniques provides valuable insights into the spatial nature, variability, and association of asthma to air pollution. Asthma patient hospitalization data of Mississippi has been analyzed and mapped using quantitative Choropleth techniques in ArcGIS. Patients have been geocoded to their respective zip codes. Potential air pollutant sources of Interstate highways, Industries, and other land use data have been integrated in common geospatial platform to understand their adverse contribution on human health. Existing hospitals and emergency clinics are being injected into analysis to further understand their proximity and easy access to patient locations. At the current level of analysis and understanding, spatial distribution of Asthma is observed in the populations of Zip code regions in gulf coast, along the interstates of south, and in counties of Northeast Mississippi. It is also found that asthma is prevalent in most of the urban population. This GIS based project would be useful to make health risk assessment and provide information support to the administrators and decision makers for establishing satellite clinics in future.

  6. The impact of mixing on Age of Air

    NASA Astrophysics Data System (ADS)

    Garny, Hella; Birner, Thomas; Bönisch, Harald

    2013-04-01

    Transport in the stratosphere is determined both by the mean meridional circulation and two-way mixing. Stratospheric age of air (AoA) is a measure of the integrated effect of all transport processes that affected an air parcel on its way through the stratosphere after crossing the tropopause. Mean AoA is often used to quantify the transport circulation in the stratosphere, namely the Brewer-Dobson Circulation (BDC). Global models project an increase in the mean meridional circulation in a changing climate, and simultaneously a decrease in AoA. However, evidence of changes in mean AoA from observations is weak. To infer from the AoA measurements on changes in the residual circulation, that cannot be measured directly, a better understanding of the relation between AoA and the residual circulation is necessary. Global models provide residual circulation data consistent with AoA, and thus can be used to investigate this relationship. We use trajectories driven only by the residual circulation to derive the hypothetical 'age' that air would have if it was transported only by the residual circulation. This quantity is referred to as 'residual circulation transit time' (RCTT). The difference between AoA and RCTT is then the additional aging of air caused by mixing processes. It is shown that this aging by mixing is positive throughout the lower stratosphere, only in the lowermost stratosphere at high latitudes, air is younger than expected from residual circulation transport only. The processes of the impact of mixing on AoA are further investigated using a simple tropical leaky pipe (TLP) model. The TLP model can explain the general increase of AoA in the lower stratosphere and above by mixing with the recirculation of air parcels. Aging by mixing is dependent both on 1) the mixing strength, that controls the fraction of air that recirculates, and 2) the residual circulation strength, that controls the speed of recirculation. Thus, stronger mixing increases aging by

  7. Mammalian laryngseal air sacs add variability to the vocal tract impedance: Physical and computational modeling

    PubMed Central

    Riede, Tobias; Tokuda, Isao T.; Munger, Jacob B.; Thomson, Scott L.

    2008-01-01

    Cavities branching off the main vocal tract are ubiquitous in nonhumans. Mammalian air sacs exist in human relatives, including all four great apes, but only a substantially reduced version exists in humans. The present paper focuses on acoustical functions of the air sacs. The hypotheses are investigated on whether the air sacs affect amplitude of utterances and∕or position of formants. A multilayer synthetic model of the vocal folds coupled with a vocal tract model was utilized. As an air sac model, four configurations were considered: open and closed uniform tube-like side branches, a rigid cavity, and an inflatable cavity. Results suggest that some air sac configurations can enhance the sound level. Furthermore, an air sac model introduces one or more additional resonance frequencies, shifting formants of the main vocal tract to some extent but not as strongly as previously suggested. In addition, dynamic range of vocalization can be extended by the air sacs. A new finding is also an increased variability of the vocal tract impedance, leading to strong nonlinear source-filter interaction effects. The experiments demonstrated that air-sac-like structures can destabilize the sound source. The results were validated by a transmission line computational model. PMID:18647005

  8. Modeling air quality in main cities of Peninsular Malaysia by using a generalized Pareto model.

    PubMed

    Masseran, Nurulkamal; Razali, Ahmad Mahir; Ibrahim, Kamarulzaman; Latif, Mohd Talib

    2016-01-01

    The air pollution index (API) is an important figure used for measuring the quality of air in the environment. The API is determined based on the highest average value of individual indices for all the variables which include sulfur dioxide (SO2), nitrogen dioxide (NO2), carbon monoxide (CO), ozone (O3), and suspended particulate matter (PM10) at a particular hour. API values that exceed the limit of 100 units indicate an unhealthy status for the exposed environment. This study investigates the risk of occurrences of API values greater than 100 units for eight urban areas in Peninsular Malaysia for the period of January 2004 to December 2014. An extreme value model, known as the generalized Pareto distribution (GPD), has been fitted to the API values found. Based on the fitted model, return period for describing the occurrences of API exceeding 100 in the different cities has been computed as the indicator of risk. The results obtained indicated that most of the urban areas considered have a very small risk of occurrence of the unhealthy events, except for Kuala Lumpur, Malacca, and Klang. However, among these three cities, it is found that Klang has the highest risk. Based on all the results obtained, the air quality standard in urban areas of Peninsular Malaysia falls within healthy limits to human beings.

  9. Modeling air quality in main cities of Peninsular Malaysia by using a generalized Pareto model.

    PubMed

    Masseran, Nurulkamal; Razali, Ahmad Mahir; Ibrahim, Kamarulzaman; Latif, Mohd Talib

    2016-01-01

    The air pollution index (API) is an important figure used for measuring the quality of air in the environment. The API is determined based on the highest average value of individual indices for all the variables which include sulfur dioxide (SO2), nitrogen dioxide (NO2), carbon monoxide (CO), ozone (O3), and suspended particulate matter (PM10) at a particular hour. API values that exceed the limit of 100 units indicate an unhealthy status for the exposed environment. This study investigates the risk of occurrences of API values greater than 100 units for eight urban areas in Peninsular Malaysia for the period of January 2004 to December 2014. An extreme value model, known as the generalized Pareto distribution (GPD), has been fitted to the API values found. Based on the fitted model, return period for describing the occurrences of API exceeding 100 in the different cities has been computed as the indicator of risk. The results obtained indicated that most of the urban areas considered have a very small risk of occurrence of the unhealthy events, except for Kuala Lumpur, Malacca, and Klang. However, among these three cities, it is found that Klang has the highest risk. Based on all the results obtained, the air quality standard in urban areas of Peninsular Malaysia falls within healthy limits to human beings. PMID:26718946

  10. Air traffic simulation in chemistry-climate model EMAC 2.41: AirTraf 1.0

    NASA Astrophysics Data System (ADS)

    Yamashita, Hiroshi; Grewe, Volker; Jöckel, Patrick; Linke, Florian; Schaefer, Martin; Sasaki, Daisuke

    2016-09-01

    Mobility is becoming more and more important to society and hence air transportation is expected to grow further over the next decades. Reducing anthropogenic climate impact from aviation emissions and building a climate-friendly air transportation system are required for a sustainable development of commercial aviation. A climate optimized routing, which avoids climate-sensitive regions by re-routing horizontally and vertically, is an important measure for climate impact reduction. The idea includes a number of different routing strategies (routing options) and shows a great potential for the reduction. To evaluate this, the impact of not only CO2 but also non-CO2 emissions must be considered. CO2 is a long-lived gas, while non-CO2 emissions are short-lived and are inhomogeneously distributed. This study introduces AirTraf (version 1.0) that performs global air traffic simulations, including effects of local weather conditions on the emissions. AirTraf was developed as a new submodel of the ECHAM5/MESSy Atmospheric Chemistry (EMAC) model. Air traffic information comprises Eurocontrol's Base of Aircraft Data (BADA Revision 3.9) and International Civil Aviation Organization (ICAO) engine performance data. Fuel use and emissions are calculated by the total energy model based on the BADA methodology and Deutsches Zentrum für Luft- und Raumfahrt (DLR) fuel flow method. The flight trajectory optimization is performed by a genetic algorithm (GA) with respect to a selected routing option. In the model development phase, benchmark tests were performed for the great circle and flight time routing options. The first test showed that the great circle calculations were accurate to -0.004 %, compared to those calculated by the Movable Type script. The second test showed that the optimal solution found by the algorithm sufficiently converged to the theoretical true-optimal solution. The difference in flight time between the two solutions is less than 0.01 %. The dependence of

  11. MODELING THE IMPACT OF AIR POLLUTION ON GLOBAL CLIMATE CHANGE

    EPA Science Inventory

    Tropospheric ozone (O3) and aerosols have major effects on climate and are the two air pollutants of most concern in the developed world. O3 is a major greenhouse gas (GHG) and light-absorbing aerosols such as black carbon (BC) also contribute to global warm...

  12. Linking Air Quality and Watershed Models for Environmental Assessments: Analysis of the Effects of Model-Specific Precipitation Estimates on Calculated Water Flux

    EPA Science Inventory

    Directly linking air quality and watershed models could provide an effective method for estimating spatially-explicit inputs of atmospheric contaminants to watershed biogeochemical models. However, to adequately link air and watershed models for wet deposition estimates, each mod...

  13. Parcel: Project for the Automatic Restructuring and Concurrent Evaluation of Lisp

    SciTech Connect

    Harrison, W.L. III; Padua, D.A.

    1987-01-01

    Parcel (Project for the Automatic Restructuring and Concurrent Evaluation of Lisp) is an investigation of the problem of compiling Lisp for evaluation on a shared memory multiprocessor. In this paper, we present an overview of the process of compilation in Parcel. This process consists, broadly, of an interprocedural analysis, followed by the function-level restructuring of the lambda expressions composing a program. We discuss both of the phases, and illustrate the steps of restructuring with a few examples. A novel representation for s-expressions is employed in Parcel, to facilitate the parallel creation and access of lists; we review this representation, and discuss its implications for the compilation process. 14 refs., 8 figs.

  14. BUILDING AN ENVIRONMENTAL TRAINING MODEL, MAPCORE - A TRAINING EXERCISE FOR AIR POLLUTION CONTROL.

    ERIC Educational Resources Information Center

    SIEGEL, GILBERT B.; SULLIVAN, DONALD M.

    NEW AIR POLLUTION CONTROL PROGRAMS HAVE RESULTED FROM THE "CLEAN AIR ACT" PASSED BY CONGRESS IN DECEMBER 1963. THE UNIVERSITY OF SOUTHERN CALIFORNIA DEVELOPED A TRAINING MODEL, CALLED "MAPCORE," WHICH PROVIDES A SEMISTRUCTURED ENVIRONMENT, IS PRACTICAL AND REALISTIC IN APPROACH, PROVIDES OPPORTUNITY FOR HIGH CREATIVITY, PROVIDES AN…

  15. (AMD) ANALYSIS OF AIR QUALITY DATA NEAR ROADWAYS USING A DISPERSION MODEL

    EPA Science Inventory

    We used a dispersion model to analyze measurements made during a field study conducted by the U.S. EPA in July-August 2006, to estimate the impact of traffic emissions on air quality at distances of tens of meters from an 8 lane highway located in Raleigh, North Carolina. The air...

  16. AIR QUALITY MODELING AT COARSE-TO-FINE SCALES IN URBAN AREAS

    EPA Science Inventory

    Urban air toxics control strategies are moving towards a community based modeling approach, with an emphasis on assessing those areas that experience high air toxic concentration levels, the so-called "hot spots". This approach will require information that accurately maps and...

  17. APPLICATION AND EVALUATION OF CMAQ IN THE UNITED STATES: AIR QUALITY FORECASTING AND RETROSPECTIVE MODELING

    EPA Science Inventory

    Presentation slides provide background on model evaluation techniques. Also included in the presentation is an operational evaluation of 2001 Community Multiscale Air Quality (CMAQ) annual simulation, and an evaluation of PM2.5 for the CMAQ air quality forecast (AQF) ...

  18. Path Forward for the Air Quality Model Evaluation International Initiative (AQMEII)

    EPA Science Inventory

    This article lays out the objectives for Phase 2 of the Air Quality Model Evaluation International Initiative (AQMEII). The inhalation of air pollutants such as ozone and fine particles has been linked to adverse impacts on human health, and the atmospheric deposition of pollutan...

  19. Micro air vehicle motion tracking and aerodynamic modeling

    NASA Astrophysics Data System (ADS)

    Uhlig, Daniel V.

    Aerodynamic performance of small-scale fixed-wing flight is not well understood, and flight data are needed to gain a better understanding of the aerodynamics of micro air vehicles (MAVs) flying at Reynolds numbers between 10,000 and 30,000. Experimental studies have shown the aerodynamic effects of low Reynolds number flow on wings and airfoils, but the amount of work that has been conducted is not extensive and mostly limited to tests in wind and water tunnels. In addition to wind and water tunnel testing, flight characteristics of aircraft can be gathered through flight testing. The small size and low weight of MAVs prevent the use of conventional on-board instrumentation systems, but motion tracking systems that use off-board triangulation can capture flight trajectories (position and attitude) of MAVs with minimal onboard instrumentation. Because captured motion trajectories include minute noise that depends on the aircraft size, the trajectory results were verified in this work using repeatability tests. From the captured glide trajectories, the aerodynamic characteristics of five unpowered aircraft were determined. Test results for the five MAVs showed the forces and moments acting on the aircraft throughout the test flights. In addition, the airspeed, angle of attack, and sideslip angle were also determined from the trajectories. Results for low angles of attack (less than approximately 20 deg) showed the lift, drag, and moment coefficients during nominal gliding flight. For the lift curve, the results showed a linear curve until stall that was generally less than finite wing predictions. The drag curve was well described by a polar. The moment coefficients during the gliding flights were used to determine longitudinal and lateral stability derivatives. The neutral point, weather-vane stability and the dihedral effect showed some variation with different trim speeds (different angles of attack). In the gliding flights, the aerodynamic characteristics

  20. Implementation of a WRF-CMAQ Air Quality Modeling System in Bogotá, Colombia

    NASA Astrophysics Data System (ADS)

    Nedbor-Gross, R.; Henderson, B. H.; Pachon, J. E.; Davis, J. R.; Baublitz, C. B.; Rincón, A.

    2014-12-01

    Due to a continuous economic growth Bogotá, Colombia has experienced air pollution issues in recent years. The local environmental authority has implemented several strategies to curb air pollution that have resulted in the decrease of PM10 concentrations since 2010. However, more activities are necessary in order to meet international air quality standards in the city. The University of Florida Air Quality and Climate group is collaborating with the Universidad de La Salle to prioritize regulatory strategies for Bogotá using air pollution simulations. To simulate pollution, we developed a modeling platform that combines the Weather Research and Forecasting Model (WRF), local emissions, and the Community Multi-scale Air Quality model (CMAQ). This platform is the first of its kind to be implemented in the megacity of Bogota, Colombia. The presentation will discuss development and evaluation of the air quality modeling system, highlight initial results characterizing photochemical conditions in Bogotá, and characterize air pollution under proposed regulatory strategies. The WRF model has been configured and applied to Bogotá, which resides in a tropical climate with complex mountainous topography. Developing the configuration included incorporation of local topography and land-use data, a physics sensitivity analysis, review, and systematic evaluation. The threshold, however, was set based on synthesis of model performance under less mountainous conditions. We will evaluate the impact that differences in autocorrelation contribute to the non-ideal performance. Air pollution predictions are currently under way. CMAQ has been configured with WRF meteorology, global boundary conditions from GEOS-Chem, and a locally produced emission inventory. Preliminary results from simulations show promising performance of CMAQ in Bogota. Anticipated results include a systematic performance evaluation of ozone and PM10, characterization of photochemical sensitivity, and air

  1. The Oak Ridge Heat Pump Models: I. A Steady-State Computer Design Model of Air-to-Air Heat Pumps

    SciTech Connect

    Fischer, S.K. Rice, C.K.

    1999-12-10

    The ORNL Heat Pump Design Model is a FORTRAN-IV computer program to predict the steady-state performance of conventional, vapor compression, electrically-driven, air-to-air heat pumps in both heating and cooling modes. This model is intended to serve as an analytical design tool for use by heat pump manufacturers, consulting engineers, research institutions, and universities in studies directed toward the improvement of heat pump performance. The Heat Pump Design Model allows the user to specify: system operating conditions, compressor characteristics, refrigerant flow control devices, fin-and-tube heat exchanger parameters, fan and indoor duct characteristics, and any of ten refrigerants. The model will compute: system capacity and COP (or EER), compressor and fan motor power consumptions, coil outlet air dry- and wet-bulb temperatures, air- and refrigerant-side pressure drops, a summary of the refrigerant-side states throughout the cycle, and overall compressor efficiencies and heat exchanger effectiveness. This report provides thorough documentation of how to use and/or modify the model. This is a revision of an earlier report containing miscellaneous corrections and information on availability and distribution of the model--including an interactive version.

  2. Parcellation of Infant Surface Atlas Using Developmental Trajectories of Multidimensional Cortical Attributes

    PubMed Central

    Li, Gang; Wang, Li; Gilmore, John H.; Lin, Weili; Shen, Dinggang

    2016-01-01

    Cortical surface atlases, equipped with anatomically and functionally defined parcellations, are of fundamental importance in neuroimaging studies. Typically, parcellations of surface atlases are derived based on the sulcal-gyral landmarks, which are extremely variable across individuals and poorly matched with microstructural and functional boundaries. Cortical developmental trajectories in infants reflect underlying changes of microstructures, which essentially determines the molecular organization and functional principles of the cortex, thus allowing better definition of developmentally, microstructurally, and functionally distinct regions, compared to conventional sulcal-gyral landmarks. Accordingly, a parcellation of infant cortical surface atlas was proposed, based on the developmental trajectories of cortical thickness in infants, revealing regional patterning of cortical growth. However, cortical anatomy is jointly characterized by biologically-distinct, multidimensional cortical attributes, i.e., cortical thickness, surface area, and local gyrification, each with its distinct genetic underpinning, cellular mechanism, and developmental trajectories. To date, the parcellations based on the development of surface area and local gyrification is still missing. To bridge this critical gap, for the first time, we parcellate an infant cortical surface atlas into distinct regions based solely on developmental trajectories of surface area and local gyrification, respectively. For each cortical attribute, we first nonlinearly fuse the subject-specific similarity matrices of vertices' developmental trajectories of all subjects into a single matrix, which helps better capture common and complementary information of the population than the conventional method of simple averaging of all subjects' matrices. Then, we perform spectral clustering based on this fused matrix. We have applied our method to parcellate an infant surface atlas using the developmental trajectories

  3. [Winter wheat area estimation with MODIS-NDVI time series based on parcel].

    PubMed

    Li, Le; Zhang, Jin-shui; Zhu, Wen-quan; Hu, Tan-gao; Hou, Dong

    2011-05-01

    Several attributes of MODIS (moderate resolution imaging spectrometer) data, especially the short temporal intervals and the global coverage, provide an extremely efficient way to map cropland and monitor its seasonal change. However, the reliability of their measurement results is challenged because of the limited spatial resolution. The parcel data has clear geo-location and obvious boundary information of cropland. Also, the spectral differences and the complexity of mixed pixels are weak in parcels. All of these make that area estimation based on parcels presents more advantage than on pixels. In the present study, winter wheat area estimation based on MODIS-NDVI time series has been performed with the support of cultivated land parcel in Tongzhou, Beijing. In order to extract the regional winter wheat acreage, multiple regression methods were used to simulate the stable regression relationship between MODIS-NDVI time series data and TM samples in parcels. Through this way, the consistency of the extraction results from MODIS and TM can stably reach up to 96% when the amount of samples accounts for 15% of the whole area. The results shows that the use of parcel data can effectively improve the error in recognition results in MODIS-NDVI based multi-series data caused by the low spatial resolution. Therefore, with combination of moderate and low resolution data, the winter wheat area estimation became available in large-scale region which lacks completed medium resolution images or has images covered with clouds. Meanwhile, it carried out the preliminary experiments for other crop area estimation.

  4. Parcellation of the human orbitofrontal cortex based on gray matter volume covariance.

    PubMed

    Liu, Huaigui; Qin, Wen; Qi, Haotian; Jiang, Tianzi; Yu, Chunshui

    2015-02-01

    The human orbitofrontal cortex (OFC) is an enigmatic brain region that cannot be parcellated reliably using diffusional and functional magnetic resonance imaging (fMRI) because there is signal dropout that results from an inherent defect in imaging techniques. We hypothesise that the OFC can be reliably parcellated into subregions based on gray matter volume (GMV) covariance patterns that are derived from artefact-free structural images. A total of 321 healthy young subjects were examined by high-resolution structural MRI. The OFC was parcellated into subregions-based GMV covariance patterns; and then sex and laterality differences in GMV covariance pattern of each OFC subregion were compared. The human OFC was parcellated into the anterior (OFCa), medial (OFCm), posterior (OFCp), intermediate (OFCi), and lateral (OFCl) subregions. This parcellation scheme was validated by the same analyses of the left OFC and the bilateral OFCs in male and female subjects. Both visual observation and quantitative comparisons indicated a unique GMV covariance pattern for each OFC subregion. These OFC subregions mainly covaried with the prefrontal and temporal cortices, cingulate cortex and amygdala. In addition, GMV correlations of most OFC subregions were similar across sex and laterality except for significant laterality difference in the OFCl. The right OFCl had stronger GMV correlation with the right inferior frontal cortex. Using high-resolution structural images, we established a reliable parcellation scheme for the human OFC, which may provide an in vivo guide for subregion-level studies of this region and improve our understanding of the human OFC at subregional levels.

  5. Use of air quality modeling results as exposure estimates in health studies

    NASA Astrophysics Data System (ADS)

    Holmes, H. A.; Ivey, C.; Friberg, M.; Zhai, X.; Balachandran, S.; Hu, Y.; Russell, A. G.; Mulholland, J. A.; Tolbert, P. E.; Sarnat, S. E.

    2013-12-01

    Air pollutant measurements from regulatory monitoring networks are commonly utilized in combination with spatial averaging techniques to develop air quality metrics for use in epidemiologic studies. While these data provide useful indicators for air pollution in a region, their temporal and spatial information are limited. The growing availability of spatially resolved health data sets (i.e., resident and county level patient records) provides an opportunity to develop and apply corresponding spatially resolved air quality metrics as enhanced exposure estimates when investigating the impact of air pollution on health outcomes. Additionally, the measured species concentrations from monitoring networks cannot directly identify specific emission sources or characterize pollutant mixtures. However, these observations in combination with chemical transport models (e.g., CMAQ) and source apportionment methods (e.g., CMB and PMF) can be used to characterize pollutant mixtures, sources and species impacting both individual locations and wider areas. Extensive analysis using a combination of air quality modeling approaches and observations may be beneficial for health studies whose goal is to assess the health impacts of pollutant mixtures, in both spatially resolved and time-series health analyses. As part of the Southeastern Center for Air Pollution and Epidemiology (SCAPE) unique methods have been developed to effectively analyze air pollution and air quality modeling data to better understand how emission sources combine to impact air quality and to provide air quality metrics for use in health assessments. This presentation will discuss the air quality modeling techniques being utilized in SCAPE investigations that are aimed at providing enhanced exposure metrics for use in spatially resolved (state of Georgia) and time-series epidemiologic analyses (St. Louis and Atlanta). To generate spatially resolved daily air quality estimates of species concentrations and source

  6. AIR DISPERSION MODELING AT THE WASTE ISOLATION PILOT PLANT

    SciTech Connect

    Rucker, D.F.

    2000-08-01

    One concern at the Waste Isolation Pilot Plant (WIPP) is the amount of alpha-emitting radionuclides or hazardous chemicals that can become airborne at the facility and reach the Exclusive Use Area boundary as the result of a release from the Waste Handling Building (WHB) or from the underground during waste emplacement operations. The WIPP Safety Analysis Report (SAR), WIPP RCRA Permit, and WIPP Emergency Preparedness Hazards Assessments include air dispersion calculations to address this issue. Meteorological conditions at the WIPP facility will dictate direction, speed, and dilution of a contaminant plume of respirable material due to chronic releases or during an accident. Due to the paucity of meteorological information at the WIPP site prior to September 1996, the Department of Energy (DOE) reports had to rely largely on unqualified climatic data from the site and neighboring Carlsbad, which is situated approximately 40 km (26 miles) to the west of the site. This report examines the validity of the DOE air dispersion calculations using new meteorological data measured and collected at the WIPP site since September 1996. The air dispersion calculations in this report include both chronic and acute releases. Chronic release calculations were conducted with the EPA-approved code, CAP88PC and the calculations showed that in order for a violation of 40 CFR61 (NESHAPS) to occur, approximately 15 mCi/yr of 239Pu would have to be released from the exhaust stack or from the WHB. This is an extremely high value. Hence, it is unlikely that NESHAPS would be violated. A site-specific air dispersion coefficient was evaluated for comparison with that used in acute dose calculations. The calculations presented in Section 3.2 and 3.3 show that one could expect a slightly less dispersive plume (larger air dispersion coefficient) given greater confidence in the meteorological data, i.e. 95% worst case meteorological conditions. Calculations show that dispersion will decrease

  7. Regional/Urban Air Quality Modeling Assessment over China Using the Models-3/CMAQ System

    NASA Astrophysics Data System (ADS)

    Fu, J. S.; Jang, C. C.; Streets, D. G.; Li, Z.; Wang, L.; Zhang, Q.; Woo, J.; Wang, B.

    2004-12-01

    China is the world's most populous country with a fast growing economy that surges in energy comsumption. It has become the second largest energy consumer after the United States although the per capita level is much lower than those found in developed or developing countries. Air pollution has become one of the most important problems of megacities such as Beijing and Shanghai and has serious impacts on public health, causes urban and regional haze. The Models-3/CMAQ modeling application that has been conducted to simulate multi-pollutants in China is presented. The modeling domains cover East Asia (36-kmx36-km) including Japan, South Korea, Korea DPR, Indonesia, Thailand, India and Mongolia, East China (12-kmx12-km) and Beijing/Tianjing, Shanghai (4-kmx4-km). For this study, the Asian emission inventory based on the emission estimates of the year 2000 that supported the NASA TRACE-P program is used. However, the TRACE-P emission inventory was developed for a different purpose such as global modeling. TRACE-P emission inventory may not be practical in urban area. There is no China national emission inventory available. Therefore, TRACE-P emission inventory is used on the East Asia and East China domains. The 8 districts of Beijing and Shanghai local emissions inventory are used to replace TRACE-P in 4-km domains. The meteorological data for the Models-3/CMAQ run are extracted from MM5. The model simulation is performed during the period January 1-20 and July 1-20, 2001 that presented the winter and summer time for China areas. The preliminary model results are shown O3 concentrations are in the range of 80 -120 ppb in the urban area. Lower urban O3 concentrations are shown in Beijing areas, possibly due to underestimation of urban man-made VOC emissions in the TRACE-P inventory and local inventory. High PM2.5 (70ug/m3 in summer and 150ug/m3 in winter) were simulated over metropolitan & downwind areas with significant secondary constituents. More comprehensive

  8. Indoor Air Quality (IAQ) model for windows, risk (version 1.0) (for microcomputers). Model-Simulation

    SciTech Connect

    1995-07-01

    A computer model, called RISK, for calculating individual exposure to indoor air pollutants from sources is presented. The model is designed to calculate exposure due to individual, as opposed to population, activities patterns and source use. The model also provides the capability to calculate risk due to the calculated exposure. RISK is the third in a series of indoor air quality (IAQ) models developed by the Indoor Environment Management Branch of U.S. EPA`s National Risk Management Research Laboratory. The model uses data on source emissions, room-to-room air flows, air exchange with the outdoors, and indoor sinks to predict concentration-time profiles for all rooms. The concentration-time profiles are then combined with individual activity patterns to estimate exposure. Risk is calculated using a risk calculation using a risk calculation framework developed by Naugle and Pierson (1991). The model allows analysis of the effects of air cleaners located in either/or both the central air circulating system or individual rooms on IAQ and exposure. The model allows simulation of a wide range of sources including long term steady state sources, on/off sources, and decaying sources. Several sources are allowed in each room. The model allows the analysis of the effects of sinks and sink re-emissions on IAQ. The results of test house experiments are compared with model predictions. The agreement between predicted concentration-time profiles and the test house data is good.

  9. NEIGHBORHOOD SCALE MODELING OF PM 2.5 AND AIR TOXICS CONCENTRATION DISTRIBUTIONS TO DRIVE HUMAN EXPOSURE MODELS

    EPA Science Inventory

    Air quality (AQ) simulation models provide a basis for implementing the National Ambient Air Quality Standards (NAAQS) and are a tool for performing risk-based assessments and for developing environmental management strategies. Fine particulate matter (PM 2.5), its constituent...

  10. Characterization of ambient air pollution for stochastic health models

    SciTech Connect

    Batterman, S.A.

    1981-08-01

    This research is an analysis of various measures of ambient air pollution useful in cross-sectional epidemiological investigations and rick assessments. The Chestnut Ridge area health effects investigation, which includes a cross-sectional study of respiratory symptoms in young children, is used as a case study. Four large coal-fired electric generating power plants are the dominant pollution sources in this area of western Pennsylvania. The air pollution data base includes four years of sulfur dioxide and five years of total suspended particulate concentrations at seventeen monitors. Some 70 different characterizations of pollution are constructed and tested. These include pollutant concentrations at various percentiles and averaging times, exceedence measures which show the amount of time a specified threshold concentration is exceeded, and several dosage measures which transform non-linear dose-response relationships onto pollutant concentrations.

  11. Constant Entropy Properties for an Approximate Model of Equilibrium Air

    NASA Technical Reports Server (NTRS)

    Hansen, C. Frederick; Hodge, Marion E.

    1961-01-01

    Approximate analytic solutions for properties of equilibrium air up to 15,000 K have been programmed for machine computation. Temperature, compressibility, enthalpy, specific heats, and speed of sound are tabulated as constant entropy functions of temperature. The reciprocal of acoustic impedance and its integral with respect to pressure are also given for the purpose of evaluating the Riemann constants for one-dimensional, isentropic flow.

  12. Modelling and simulation of air-conditioning cycles

    NASA Astrophysics Data System (ADS)

    Rais, Sandi; Kadono, Yoshinori; Murayama, Katsunori; Minakuchi, Kazuya; Takeuchi, Hisae; Hasegawa, Tatsuya

    2016-05-01

    The heat-pump cycle for air conditioning was investigated both numerically and experimentally by evaluating the coefficient of performance (COP) under Japanese Industrial Standard (JIS B 8619:1999) and ANSI/AHRI standard 750-2007 operating conditions. We used two expansion valve coefficients Cv_{(\\varphi )} = 0.12 for standard operating conditions (Case 1) approaching 1.3 MPa at high pressure and 0.2 MPa at low pressure, and Cv_{(\\varphi )} = 0.06 namely poor operating conditions (Case 2). To improve the performance of the air conditioner, we compared the performance for two outside air temperatures, 35 and 40 °C (Case 3). The simulation and experiment comparison resulted the decreasing of the COP for standard operating condition is equal to 14 %, from 3.47 to 2.95 and a decrease of the cooling capacity is equal to 18 %, from 309.72 to 253.53 W. This result was also occurred in poor operating condition which the COP was superior at 35 °C temperature.

  13. MODELS-3 COMMUNITY MULTISCALE AIR QUALITY (CMAQ) MODEL AEROSOL COMPONENT 2. MODEL EVALUATION

    EPA Science Inventory

    Ambient air concentrations of particulate matter (atmospheric suspensions of solid of liquid materials, i.e., aerosols) continue to be a major concern for the U.S. Environmental Protection Agency (EPA). High particulate matter (PM) concentrations are associated not only with adv...

  14. MODELING AIR TOXICS AND PM 2.5 CONCENTRATION FIELDS AS A MEANS FOR FACILITATING HUMAN EXPOSURE ASSESSMENTS

    EPA Science Inventory

    The capability of the US EPA Models-3/Community Multiscale Air Quality (CMAQ) modeling system is extended to provide gridded ambient air quality concentration fields at fine scales. These fields will drive human exposure to air toxics and fine particulate matter (PM2.5) models...

  15. GraSP: Geodesic Graph-based Segmentation With Shape Priors for the Functional Parcellation of the Cortex

    PubMed Central

    Honnorat, N.; Eavani, H.; Satterthwaite, T. D.; Gur, R. E.; Gur, R. C.; Davatzikos, C.

    2014-01-01

    Resting-state functional MRI is a powerful technique for mapping the functional organization of the human brain. However, for many types of connectivity analysis, high-resolution voxelwise analyses are computationally infeasible and dimensionality reduction is typically used to limit the number of network nodes. Most commonly, network nodes are defined using standard anatomic atlases that do not align well with functional neuroanatomy or regions of interest covering a small portion of the cortex. Data-driven parcellation methods seek to overcome such limitations, but existing approaches are highly dependent on initialization procedures and produce spatially fragmented parcels or overly isotropic parcels that are unlikely to be biologically grounded. In this paper, we propose a novel graph-based parcellation method that relies on a discrete Markov Random Field framework. The spatial connectedness of the parcels is explicitly enforced by shape priors. The shape of the parcels is adapted to underlying data through the use of functional geodesic distances. Our method is initialization-free and rapidly segments the cortex in a single optimization. The performance of the method was assessed using a large developmental cohort of more than 850 subjects. Compared to two prevalent parcellation methods, our approach provides superior reproducibility for a similar data fit. Furthermore, compared to other methods, it avoids incoherent parcels. Finally, the method’s utility is demonstrated through its ability to detect strong brain developmental effects that are only weakly observed using other methods. PMID:25462796

  16. 25 CFR 166.303 - Can more than one parcel of Indian land be combined into one permit?

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 25 Indians 1 2010-04-01 2010-04-01 false Can more than one parcel of Indian land be combined into one permit? 166.303 Section 166.303 Indians BUREAU OF INDIAN AFFAIRS, DEPARTMENT OF THE INTERIOR LAND AND WATER GRAZING PERMITS Land and Operations Management § 166.303 Can more than one parcel of...

  17. GraSP: geodesic Graph-based Segmentation with Shape Priors for the functional parcellation of the cortex.

    PubMed

    Honnorat, N; Eavani, H; Satterthwaite, T D; Gur, R E; Gur, R C; Davatzikos, C

    2015-02-01

    Resting-state functional MRI is a powerful technique for mapping the functional organization of the human brain. However, for many types of connectivity analysis, high-resolution voxelwise analyses are computationally infeasible and dimensionality reduction is typically used to limit the number of network nodes. Most commonly, network nodes are defined using standard anatomic atlases that do not align well with functional neuroanatomy or regions of interest covering a small portion of the cortex. Data-driven parcellation methods seek to overcome such limitations, but existing approaches are highly dependent on initialization procedures and produce spatially fragmented parcels or overly isotropic parcels that are unlikely to be biologically grounded. In this paper, we propose a novel graph-based parcellation method that relies on a discrete Markov Random Field framework. The spatial connectedness of the parcels is explicitly enforced by shape priors. The shape of the parcels is adapted to underlying data through the use of functional geodesic distances. Our method is initialization-free and rapidly segments the cortex in a single optimization. The performance of the method was assessed using a large developmental cohort of more than 850 subjects. Compared to two prevalent parcellation methods, our approach provides superior reproducibility for a similar data fit. Furthermore, compared to other methods, it avoids incoherent parcels. Finally, the method's utility is demonstrated through its ability to detect strong brain developmental effects that are only weakly observed using other methods.

  18. AIR QUALITY MODELING OF HAZARDOUS POLLUTANTS: CURRENT STATUS AND FUTURE DIRECTIONS

    EPA Science Inventory

    The paper presents a review of current air toxics modeling applications and discusses possible advanced approaches. Many applications require the ability to predict hot spots from industrial sources or large roadways that are needed for community health and Environmental Justice...

  19. Improved Modeling of Residential Air Conditioners and Heat Pumps for Energy Calculations

    SciTech Connect

    Cutler, D.; Winkler, J.; Kruis, N.; Christensen, C.; Brendemuehl, M.

    2013-01-01

    This report presents improved air conditioner and heat pump modeling methods in the context of whole-building simulation tools, with the goal of enabling more accurate evaluation of cost effective equipment upgrade opportunities and efficiency improvements in residential buildings.

  20. APPLICATION OF BAYESIAN MONTE CARLO ANALYSIS TO A LAGRANGIAN PHOTOCHEMICAL AIR QUALITY MODEL. (R824792)

    EPA Science Inventory

    Uncertainties in ozone concentrations predicted with a Lagrangian photochemical air quality model have been estimated using Bayesian Monte Carlo (BMC) analysis. Bayesian Monte Carlo analysis provides a means of combining subjective "prior" uncertainty estimates developed ...

  1. Modeling U.S. air pollutant emissions and controls in GCAM-USA

    EPA Science Inventory

    We describe extensions to the GCAM-USA modeling framework that facilitate exploration of the co-benefits, tradeoffs and synergies among strategies for addressing climate, air quality, and other environmental goals.

  2. A FRAMEWORK FOR FINE-SCALE COMPUTATIONAL FLUID DYNAMICS AIR QUALITY MODELING AND ANALYSIS

    EPA Science Inventory

    Fine-scale Computational Fluid Dynamics (CFD) simulation of pollutant concentrations within roadway and building microenvironments is feasible using high performance computing. Unlike currently used regulatory air quality models, fine-scale CFD simulations are able to account rig...

  3. Evolution of soot size distribution in premixed ethylene/air and ethylene/benzene/air flames: Experimental and modeling study

    SciTech Connect

    Echavarria, Carlos A.; Sarofim, Adel F.; Lighty, JoAnn S.; D'Anna, Andrea

    2011-01-15

    The effect of benzene concentration in the initial fuel on the evolution of soot size distribution in ethylene/air and ethylene/benzene/air flat flames was characterized by experimental measurements and model predictions of size and number concentration within the flames. Experimentally, a scanning mobility particle sizer was used to allow spatially resolved and online measurements of particle concentration and sizes in the nanometer-size range. The model couples a detailed kinetic scheme with a discrete-sectional approach to follow the transition from gas-phase to nascent particles and their coagulation to larger soot particles. The evolution of soot size distribution (experimental and modeled) in pure ethylene and ethylene flames doped with benzene showed a typical nucleation-sized (since particles do not actually nucleate in the classical sense particle inception is often used in place of nucleation) mode close to the burner surface, and a bimodal behavior at greater height above burner (HAB). However, major features were distinguished between the data sets. The growth of nucleation and agglomeration-sized particles was faster for ethylene/benzene/air flames, evidenced by the earlier presence of bimodality in these flames. The most significant changes in size distribution were attributed to an increase in benzene concentration in the initial fuel. However, these changes were more evident for high temperature flames. In agreement with the experimental data, the model also predicted the decrease of nucleation-sized particles in the postflame region for ethylene flames doped with benzene. This behavior was associated with the decrease of soot precursors after the main oxidation zone of the flames. (author)

  4. Low GWP Refrigerants Modelling Study for a Room Air Conditioner Having Microchannel Heat Exchangers

    SciTech Connect

    Shen, Bo; Bhandari, Mahabir S

    2016-01-01

    Microchannel heat exchangers (MHX) have found great successes in residential and commercial air conditioning applications, being compact heat exchangers, to reduce refrigerant charge and material cost. This investigation aims to extend the application of MHXs in split, room air conditioners (RAC), per fundamental heat exchanger and system modelling. For this paper, microchannel condenser and evaporator models were developed, using a segment-to-segment modelling approach. The microchannel heat exchanger models were integrated to a system design model. The system model is able to predict the performance indices, such as cooling capacity, efficiency, sensible heat ratio, etc. Using the calibrated system and heat exchanger models, we evaluated numerous low GWP (global warming potential) refrigerants. The predicted system performance indices, e.g. cooling efficiency, compressor discharge temperature, and required compressor displacement volume etc., are compared. Suitable replacements for R22 and R-410A for the room air conditioner application are recommended.

  5. A stochastic simulation model to predict future air quality in protected areas

    NASA Astrophysics Data System (ADS)

    Stavros, E.; McKenzie, D.; Larkin, N.; Strand, T.; Lamb, B. K.

    2010-12-01

    It is widely accepted in both scientific and political communities such as the Intergovernmental Panel on Climate Change (IPCC) and the Environmental Protection Agency (EPA), that climate is changing. Previous studies have shown that expected changes in climate will increase the severity of wild fire. It is necessary to assess the impact of global climate change on wildfire and consequent effects on air quality in order to meet existing air quality regulations such as the Regional Haze Rule, which regulates visibility in Class 1 or “pristine areas”, and the National Ambient Air Quality Standards (NAAQS). The challenge in such an assessment lies in not only integrating disciplines (climatology, fire ecology, air chemistry), but also in bridging knowledge across temporal (hourly to decadal) and spatial scales (local to global). In response to this challenge, we are integrating a stochastic model to simulate fire events, the Fire Scenario Builder (FSB), and the BlueSky Modeling Framework, which has a strong record of successfully linking wildfire emissions to air quality. FSB integrates fuel information and meteorological data to estimate regional fire season summary statistics such as total area burned and number of fire starts. The Blue Sky Modeling Framework then simulates total fuel consumption and smoke emissions both in local air sheds and downwind. Emissions are then fed into the Community Multiscale Air Quality (CMAQ) model through Sparse Matrix Operator Kernel Emissions Modeling System (SMOKE). The goal of this research is threefold: 1) to compare emission results from the FSB-Blue Sky integration for current vs. future decades; 2) to assess model uncertainty, by comparing model output to observations, analyzing parameter sensitivity, and verifying the theoretical basis of FSB model structure; and, 3) prepare data files for analysis on air quality.

  6. Choosing the Appropriate Model Resolution for Public-Health-Relevant Air Quality Simulations

    NASA Astrophysics Data System (ADS)

    Holloway, T.; Kinney, P. L.

    2002-05-01

    Atmospheric chemistry models offer a powerful tool for assessing health impacts of air pollution. They may be used to estimate air quality away from monitoring stations, consider future scenarios of energy use or climate change, and examine how individual components of emissions, chemistry, and transport contribute to observed patterns. However, the scales necessary for evaluating health impacts of air pollution are not well-defined. What model resolution is needed to capture variability in ozone or PM concentrations associated with variability in respiratory disease? The current study addresses this question by examining spatial patterns in the correlation of air quality and morbidity data in New York State. Here, we present initial results based on data from New York Statewide Planning and Research Cooperative System (SPARCS) and US EPA Aerometric Information Retrieval System (AIRS). Timeseries correlations between air quality (ozone and PM) and respiratory disease are evaluated on different scales of data aggregation. We examine how correlation depends on the level of spatial averaging and on the timescale over which correlations are considered. These results will inform modeling studies, in part defining what model resolution is appropriate for simulating air quality relevant to public health assessments.

  7. Numerical simulation of air flow in a model of lungs with mouth cavity

    NASA Astrophysics Data System (ADS)

    Elcner, Jakub; Lizal, Frantisek; Jedelsky, Jan; Jicha, Miroslav

    2012-04-01

    The air flow in a realistic geometry of human lung is simulated with computational flow dynamics approach as stationary inspiration. Geometry used for the simulation includes oral cavity, larynx, trachea and bronchial tree up to the seventh generation of branching. Unsteady RANS approach was used for the air flow simulation. Velocities corresponding to 15, 30 and 60 litres/min of flow rate were set as boundary conditions at the inlet to the model. These flow rates are frequently used as a representation of typical human activities. Character of air flow in the model for these different flow rates is discussed with respect to future investigation of particle deposition.

  8. The Use of Regulatory Air Quality Models to Develop Successful Ozone Attainment Strategies

    NASA Astrophysics Data System (ADS)

    Canty, T. P.; Salawitch, R. J.; Dickerson, R. R.; Ring, A.; Goldberg, D. L.; He, H.; Anderson, D. C.; Vinciguerra, T.

    2015-12-01

    The Environmental Protection Agency (EPA) recently proposed lowering the 8-hr ozone standard to between 65-70 ppb. Not all regions of the U.S. are in attainment of the current 75 ppb standard and it is expected that many regions currently in attainment will not meet the future, lower surface ozone standard. Ozone production is a nonlinear function of emissions, biological processes, and weather. Federal and state agencies rely on regulatory air quality models such as the Community Multi-Scale Air Quality (CMAQ) model and Comprehensive Air Quality Model with Extensions (CAMx) to test ozone precursor emission reduction strategies that will bring states into compliance with the National Ambient Air Quality Standards (NAAQS). We will describe various model scenarios that simulate how future limits on emission of ozone precursors (i.e. NOx and VOCs) from sources such as power plants and vehicles will affect air quality. These scenarios are currently being developed by states required to submit a State Implementation Plan to the EPA. Projections from these future case scenarios suggest that strategies intended to control local ozone may also bring upwind states into attainment of the new NAAQS. Ground based, aircraft, and satellite observations are used to ensure that air quality models accurately represent photochemical processes within the troposphere. We will highlight some of the improvements made to the CMAQ and CAMx model framework based on our analysis of NASA observations obtained by the OMI instrument on the Aura satellite and by the DISCOVER-AQ field campaign.

  9. Modeling indoor air pollution of outdoor origin in homes of SAPALDIA subjects in Switzerland.

    PubMed

    Meier, Reto; Schindler, Christian; Eeftens, Marloes; Aguilera, Inmaculada; Ducret-Stich, Regina E; Ineichen, Alex; Davey, Mark; Phuleria, Harish C; Probst-Hensch, Nicole; Tsai, Ming-Yi; Künzli, Nino

    2015-09-01

    Given the shrinking spatial contrasts in outdoor air pollution in Switzerland and the trends toward tightly insulated buildings, the Swiss Cohort Study on Air Pollution and Lung and Heart Diseases in Adults (SAPALDIA) needs to understand to what extent outdoor air pollution remains a determinant for residential indoor exposure. The objectives of this paper are to identify determining factors for indoor air pollution concentrations of particulate matter (PM), ultrafine particles in the size range from 15 to 300nm, black smoke measured as light absorbance of PM (PMabsorbance) and nitrogen dioxide (NO2) and to develop predictive indoor models for SAPALDIA. Multivariable regression models were developed based on indoor and outdoor measurements among homes of selected SAPALDIA participants in three urban (Basel, Geneva, Lugano) and one rural region (Wald ZH) in Switzerland, various home characteristics and reported indoor sources such as cooking. Outdoor levels of air pollutants were important predictors for indoor air pollutants, except for the coarse particle fraction. The fractions of outdoor concentrations infiltrating indoors were between 30% and 66%, the highest one was observed for PMabsorbance. A modifying effect of open windows was found for NO2 and the ultrafine particle number concentration. Cooking was associated with increased particle and NO2 levels. This study shows that outdoor air pollution remains an important determinant of residential indoor air pollution in Switzerland.

  10. Modeling indoor air pollution of outdoor origin in homes of SAPALDIA subjects in Switzerland.

    PubMed

    Meier, Reto; Schindler, Christian; Eeftens, Marloes; Aguilera, Inmaculada; Ducret-Stich, Regina E; Ineichen, Alex; Davey, Mark; Phuleria, Harish C; Probst-Hensch, Nicole; Tsai, Ming-Yi; Künzli, Nino

    2015-09-01

    Given the shrinking spatial contrasts in outdoor air pollution in Switzerland and the trends toward tightly insulated buildings, the Swiss Cohort Study on Air Pollution and Lung and Heart Diseases in Adults (SAPALDIA) needs to understand to what extent outdoor air pollution remains a determinant for residential indoor exposure. The objectives of this paper are to identify determining factors for indoor air pollution concentrations of particulate matter (PM), ultrafine particles in the size range from 15 to 300nm, black smoke measured as light absorbance of PM (PMabsorbance) and nitrogen dioxide (NO2) and to develop predictive indoor models for SAPALDIA. Multivariable regression models were developed based on indoor and outdoor measurements among homes of selected SAPALDIA participants in three urban (Basel, Geneva, Lugano) and one rural region (Wald ZH) in Switzerland, various home characteristics and reported indoor sources such as cooking. Outdoor levels of air pollutants were important predictors for indoor air pollutants, except for the coarse particle fraction. The fractions of outdoor concentrations infiltrating indoors were between 30% and 66%, the highest one was observed for PMabsorbance. A modifying effect of open windows was found for NO2 and the ultrafine particle number concentration. Cooking was associated with increased particle and NO2 levels. This study shows that outdoor air pollution remains an important determinant of residential indoor air pollution in Switzerland. PMID:26070024

  11. Catchment-scale hydrologic implications of parcel-level stormwater management (Ohio USA)

    NASA Astrophysics Data System (ADS)

    Shuster, William; Rhea, Lee

    2013-04-01

    SummaryThe effectiveness of stormwater management strategies is a key issue affecting decision making on urban water resources management, and so proper monitoring and analysis of pilot studies must be addressed before drawing conclusions. We performed a pilot study in the suburban Shepherd Creek watershed located in Cincinnati, Ohio to evaluate the practicality of voluntary incentives for stormwater quantity reduction on privately owned suburban properties. Stream discharge and precipitation were monitored 3 years before and after implementation of the stormwater management treatments. To implement stormwater control measures, we elicited the participation of citizen landowners with two successive reverse-auctions. Auctions were held in spring 2007, and 2008, resulting in the installation of 85 rain gardens and 174 rain barrels. We demonstrated an analytic process of increasing model flexibility to determine hydrologic effectiveness of stormwater management at the sub-catchment level. A significant albeit small proportion of total variance was explained by both the effects of study period (˜69%) and treatment-vs.-control (˜7%). Precipitation-discharge relationships were synthesized in estimated unit hydrographs, which were decomposed and components tested for influence of treatments. Analysis of unit hydrograph parameters showed a weakened correlation between precipitation and discharge, and support the output from the initial model that parcel-level green infrastructure added detention capacity to treatment basins. We conclude that retrofit management of stormwater runoff quantity with green infrastructure in a small suburban catchment can be successfully initiated with novel economic incentive programs, and that these measures can impart a small, but statistically significant decrease in otherwise uncontrolled runoff volume. Given consistent monitoring data and analysis, water resource managers can use our approach as a way to estimate actual effectiveness of

  12. Statistical modeling of urban air temperature distributions under different synoptic conditions

    NASA Astrophysics Data System (ADS)

    Beck, Christoph; Breitner, Susanne; Cyrys, Josef; Hald, Cornelius; Hartz, Uwe; Jacobeit, Jucundus; Richter, Katja; Schneider, Alexandra; Wolf, Kathrin

    2015-04-01

    Within urban areas air temperature may vary distinctly between different locations. These intra-urban air temperature variations partly reach magnitudes that are relevant with respect to human thermal comfort. Therefore and furthermore taking into account potential interrelations with other health related environmental factors (e.g. air quality) it is important to estimate spatial patterns of intra-urban air temperature distributions that may be incorporated into urban planning processes. In this contribution we present an approach to estimate spatial temperature distributions in the urban area of Augsburg (Germany) by means of statistical modeling. At 36 locations in the urban area of Augsburg air temperatures are measured with high temporal resolution (4 min.) since December 2012. These 36 locations represent different typical urban land use characteristics in terms of varying percentage coverages of different land cover categories (e.g. impervious, built-up, vegetated). Percentage coverages of these land cover categories have been extracted from different sources (Open Street Map, European Urban Atlas, Urban Morphological Zones) for regular grids of varying size (50, 100, 200 meter horizonal resolution) for the urban area of Augsburg. It is well known from numerous studies that land use characteristics have a distinct influence on air temperature and as well other climatic variables at a certain location. Therefore air temperatures at the 36 locations are modeled utilizing land use characteristics (percentage coverages of land cover categories) as predictor variables in Stepwise Multiple Regression models and in Random Forest based model approaches. After model evaluation via cross-validation appropriate statistical models are applied to gridded land use data to derive spatial urban air temperature distributions. Varying models are tested and applied for different seasons and times of the day and also for different synoptic conditions (e.g. clear and calm

  13. Recommended direct simulation Monte Carlo collision model parameters for modeling ionized air transport processes

    NASA Astrophysics Data System (ADS)

    Swaminathan-Gopalan, Krishnan; Stephani, Kelly A.

    2016-02-01

    A systematic approach for calibrating the direct simulation Monte Carlo (DSMC) collision model parameters to achieve consistency in the transport processes is presented. The DSMC collision cross section model parameters are calibrated for high temperature atmospheric conditions by matching the collision integrals from DSMC against ab initio based collision integrals that are currently employed in the Langley Aerothermodynamic Upwind Relaxation Algorithm (LAURA) and Data Parallel Line Relaxation (DPLR) high temperature computational fluid dynamics solvers. The DSMC parameter values are computed for the widely used Variable Hard Sphere (VHS) and the Variable Soft Sphere (VSS) models using the collision-specific pairing approach. The recommended best-fit VHS/VSS parameter values are provided over a temperature range of 1000-20 000 K for a thirteen-species ionized air mixture. Use of the VSS model is necessary to achieve consistency in transport processes of ionized gases. The agreement of the VSS model transport properties with the transport properties as determined by the ab initio collision integral fits was found to be within 6% in the entire temperature range, regardless of the composition of the mixture. The recommended model parameter values can be readily applied to any gas mixture involving binary collisional interactions between the chemical species presented for the specified temperature range.

  14. Assessing the ability of mechanistic volatilization models to simulate soil surface conditions: a study with the Volt'Air model.

    PubMed

    Garcia, L; Bedos, C; Génermont, S; Braud, I; Cellier, P

    2011-09-01

    Ammonia and pesticide volatilization in the field is a surface phenomenon involving physical and chemical processes that depend on the soil surface temperature and water content. The water transfer, heat transfer and energy budget sub models of volatilization models are adapted from the most commonly accepted formalisms and parameterizations. They are less detailed than the dedicated models describing water and heat transfers and surface status. The aim of this work was to assess the ability of one of the available mechanistic volatilization models, Volt'Air, to accurately describe the pedo-climatic conditions of a soil surface at the required time and space resolution. The assessment involves: (i) a sensitivity analysis, (ii) an evaluation of Volt'Air outputs in the light of outputs from a reference Soil-Vegetation-Atmosphere Transfer model (SiSPAT) and three experimental datasets, and (iii) the study of three tests based on modifications of SiSPAT to establish the potential impact of the simplifying assumptions used in Volt'Air. The analysis confirmed that a 5 mm surface layer was well suited, and that Volt'Air surface temperature correlated well with the experimental measurements as well as with SiSPAT outputs. In terms of liquid water transfers, Volt'Air was overall consistent with SiSPAT, with discrepancies only during major rainfall events and dry weather conditions. The tests enabled us to identify the main source of the discrepancies between Volt'Air and SiSPAT: the lack of gaseous water transfer description in Volt'Air. They also helped to explain why neither Volt'Air nor SiSPAT was able to represent lower values of surface water content: current classical water retention and hydraulic conductivity models are not yet adapted to cases of very dry conditions. Given the outcomes of this study, we discuss to what extent the volatilization models can be improved and the questions they pose for current research in water transfer modeling and parameterization.

  15. A Novel Biobjective Risk-Based Model for Stochastic Air Traffic Network Flow Optimization Problem

    PubMed Central

    Cai, Kaiquan; Jia, Yaoguang; Zhu, Yanbo; Xiao, Mingming

    2015-01-01

    Network-wide air traffic flow management (ATFM) is an effective way to alleviate demand-capacity imbalances globally and thereafter reduce airspace congestion and flight delays. The conventional ATFM models assume the capacities of airports or airspace sectors are all predetermined. However, the capacity uncertainties due to the dynamics of convective weather may make the deterministic ATFM measures impractical. This paper investigates the stochastic air traffic network flow optimization (SATNFO) problem, which is formulated as a weighted biobjective 0-1 integer programming model. In order to evaluate the effect of capacity uncertainties on ATFM, the operational risk is modeled via probabilistic risk assessment and introduced as an extra objective in SATNFO problem. Computation experiments using real-world air traffic network data associated with simulated weather data show that presented model has far less constraints compared to stochastic model with nonanticipative constraints, which means our proposed model reduces the computation complexity. PMID:26180842

  16. Aircraft/Air Traffic Management Functional Analysis Model: Technical Description. 2.0

    NASA Technical Reports Server (NTRS)

    Etheridge, Melvin; Plugge, Joana; Retina, Nusrat

    1998-01-01

    The Aircraft/Air Traffic Management Functional Analysis Model, Version 2.0 (FAM 2.0), is a discrete event simulation model designed to support analysis of alternative concepts in air traffic management and control. FAM 2.0 was developed by the Logistics Management Institute (LMI) under a National Aeronautics and Space Administration (NASA) contract. This document provides a technical description of FAM 2.0 and its computer files to enable the modeler and programmer to make enhancements or modifications to the model. Those interested in a guide for using the model in analysis should consult the companion document, Aircraft/Air Traffic Management Functional Analysis Model, Version 2.0 Users Manual.

  17. A Novel Biobjective Risk-Based Model for Stochastic Air Traffic Network Flow Optimization Problem.

    PubMed

    Cai, Kaiquan; Jia, Yaoguang; Zhu, Yanbo; Xiao, Mingming

    2015-01-01

    Network-wide air traffic flow management (ATFM) is an effective way to alleviate demand-capacity imbalances globally and thereafter reduce airspace congestion and flight delays. The conventional ATFM models assume the capacities of airports or airspace sectors are all predetermined. However, the capacity uncertainties due to the dynamics of convective weather may make the deterministic ATFM measures impractical. This paper investigates the stochastic air traffic network flow optimization (SATNFO) problem, which is formulated as a weighted biobjective 0-1 integer programming model. In order to evaluate the effect of capacity uncertainties on ATFM, the operational risk is modeled via probabilistic risk assessment and introduced as an extra objective in SATNFO problem. Computation experiments using real-world air traffic network data associated with simulated weather data show that presented model has far less constraints compared to stochastic model with nonanticipative constraints, which means our proposed model reduces the computation complexity. PMID:26180842

  18. The NASA Lightning Nitrogen Oxides Model (LNOM): Application to Air Quality Modeling

    NASA Technical Reports Server (NTRS)

    Koshak, William; Peterson, Harold; Khan, Maudood; Biazar, Arastoo; Wang, Lihua

    2011-01-01

    Recent improvements to the NASA Marshall Space Flight Center Lightning Nitrogen Oxides Model (LNOM) and its application to the Community Multiscale Air Quality (CMAQ) modeling system are discussed. The LNOM analyzes Lightning Mapping Array (LMA) and National Lightning Detection Network(TradeMark)(NLDN) data to estimate the raw (i.e., unmixed and otherwise environmentally unmodified) vertical profile of lightning NO(x) (= NO + NO2). The latest LNOM estimates of lightning channel length distributions, lightning 1-m segment altitude distributions, and the vertical profile of lightning NO(x) are presented. The primary improvement to the LNOM is the inclusion of non-return stroke lightning NOx production due to: (1) hot core stepped and dart leaders, (2) stepped leader corona sheath, K-changes, continuing currents, and M-components. The impact of including LNOM-estimates of lightning NO(x) for an August 2006 run of CMAQ is discussed.

  19. Ridge formation in the lower stratosphere and its influence on ozone transport: A general circulation model study during late January 1992

    SciTech Connect

    Orsolini, Y.; Cariolle, D.; Deque, M.

    1995-06-20

    This article presents the results of observations and simulations applied to the study of an ozone mini-hole observed over Europe during January 1992, during part of the observational phase of the European Arctic Stratospheric Ozone Experiment (EASOE). The authors made use of a general circulation model to simulate the transport of air parcels at different atmospheric altitudes in order to attempt to mimic the commonly observed structures recorded from satellite ozone surveys. The simulation indicates that this hole in part originated with the motion toward the polar regions of an anticyclonic ridge in the lower altitudes of the stratosphere. Motion of air parcels from subtropical regions, and mixing ratios and potential vorticity effects were also simulated.

  20. Fuzzy-GA modeling in air quality assessment.

    PubMed

    Yadav, Jyoti; Kharat, Vilas; Deshpande, Ashok

    2015-04-01

    In this paper, the authors have suggested and implemented the defined soft computing methods in air quality classification with case studies. The first study relates to the application of Fuzzy C mean (FCM) clustering method in estimating pollution status in cities of Maharashtra State, India. In this study, the computation of weighting factor using a new concept of reference group is successfully demonstrated. The authors have also investigated the efficacy of fuzzy set theoretic approach in combination with genetic algorithm in straightway describing air quality in linguistic terms with linguistic degree of certainty attached to each description using Zadeh-Deshpande (ZD) approach. Two metropolitan cities viz., Mumbai in India and New York in the USA are identified for the assessment of the pollution status due to their somewhat similar geographical features. The case studies infer that the fuzzy sets drawn on the basis of expert knowledge base for the criteria pollutants are not much different from those obtained using genetic algorithm. Pollution forecast using various methods including fuzzy time series forms an integral part of the paper.

  1. Models of aire-dependent gene regulation for thymic negative selection.

    PubMed

    Danso-Abeam, Dina; Humblet-Baron, Stephanie; Dooley, James; Liston, Adrian

    2011-01-01

    Mutations in the autoimmune regulator (AIRE) gene lead to autoimmune polyendocrinopathy syndrome type 1 (APS1), characterized by the development of multi-organ autoimmune damage. The mechanism by which defects in AIRE result in autoimmunity has been the subject of intense scrutiny. At the cellular level, the working model explains most of the clinical and immunological characteristics of APS1, with AIRE driving the expression of tissue-restricted antigens (TRAs) in the epithelial cells of the thymic medulla. This TRA expression results in effective negative selection of TRA-reactive thymocytes, preventing autoimmune disease. At the molecular level, the mechanism by which AIRE initiates TRA expression in the thymic medulla remains unclear. Multiple different models for the molecular mechanism have been proposed, ranging from classical transcriptional activity, to random induction of gene expression, to epigenetic tag recognition effect, to altered cell biology. In this review, we evaluate each of these models and discuss their relative strengths and weaknesses.

  2. A FRAMEWORK FOR FINE-SCALE COMPUTATIONAL FLUID DYNAMICS AIR QUALITY MODELING AND ANALYSIS

    EPA Science Inventory

    This paper discusses a framework for fine-scale CFD modeling that may be developed to complement the present Community Multi-scale Air Quality (CMAQ) modeling system which itself is a computational fluid dynamics model. A goal of this presentation is to stimulate discussions on w...

  3. MULTIPOLLUTANT MODEL FOR ESTIMATING THE IMPACT OF POLLUTANTS ON INDOOR AIR QUALITY

    EPA Science Inventory

    The paper discusses a multipollutant model for estimating the impact of pollutant on indoor air quality (IAQ). [NOTE: Most existing IAQ models are not well suited for analysis of the impacts of sources that emit several pollutants into the indoor environment. These models are als...

  4. 9 CFR 325.2 - Parcel post and ferries deemed carriers.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 9 Animals and Animal Products 2 2010-01-01 2010-01-01 false Parcel post and ferries deemed carriers. 325.2 Section 325.2 Animals and Animal Products FOOD SAFETY AND INSPECTION SERVICE, DEPARTMENT OF... to transportation by ferry of any products loaded on a truck or other vehicle, or otherwise moved...

  5. 76 FR 13000 - Transfer of Commercial First-Class Mail Parcels to Competitive Product List

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-03-09

    ... From the Federal Register Online via the Government Publishing Office POSTAL SERVICE Transfer of Commercial First-Class Mail Parcels to Competitive Product List AGENCY: Postal Service.\\TM\\ ACTION: Notice. SUMMARY: The Postal Service hereby provides notice that it has filed a request with the Postal...

  6. Archaeological Survey of 56 Preselected Parcels on the AridLands Ecology Reserve

    SciTech Connect

    J. J. Sharpe.

    1999-04-22

    An archaeological survey of 56 preselected parcels on the Fitzner-Eberhardt Arid Lands Ecology (ALE) Reserve was undertaken in support of compensatory mitigation for the construction of the Environmental Restoration Disposal Facility (ERDF) cells 3 and 4 on the Hanford Site. This report presents the findings of the archaeological survey.

  7. 76 FR 14284 - Domestic Shipping Services Product Launch of Parcel Select Regional Ground

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-03-16

    .... Enter a minimum of 200 pieces or 50 pounds of mail for each mailing. Use the Electronic Verification... (electronic option only), insurance, and Hold For Pickup service. Markings and Mail Preparation The basic...); Standard Mail prepared as Not Flat-Machinable pieces or as machinable or irregular parcels...

  8. Remote Sensing Characterization of the Urban Landscape for Improvement of Air Quality Modeling

    NASA Technical Reports Server (NTRS)

    Quattrochi, Dale A.; Estes, Maurice G., Jr.; Khan, Maudood

    2005-01-01

    The urban landscape is inherently complex and this complexity is not adequately captured in air quality models, particularly the Community Multiscale Air Quality (CMAQ) model that is used to assess whether urban areas are in attainment of EPA air quality standards, primarily for ground level ozone. This inadequacy of the CMAQ model to sufficiently respond to the heterogeneous nature of the urban landscape can impact how well the model predicts ozone pollutant levels over metropolitan areas and ultimately, whether cities exceed EPA ozone air quality standards. We are exploring the utility of high-resolution remote sensing data and urban growth projections as improved inputs to the meteorology component of the CMAQ model focusing on the Atlanta, Georgia metropolitan area as a case study. These growth projections include "business as usual" and "smart growth" scenarios out to 2030. The growth projections illustrate the effects of employing urban heat island mitigation strategies, such as increasing tree canopy and albedo across the Atlanta metro area, in moderating ground-level ozone and air temperature, compared to "business as usual" simulations in which heat island mitigation strategies are not applied. The National Land Cover Dataset at 30m resolution is being used as the land use/land cover input and aggregated to the 4km scale for the MM5 mesoscale meteorological model and the (CMAQ) modeling schemes. Use of these data has been found to better characterize low densityhburban development as compared with USGS 1 km land use/land cover data that have traditionally been used in modeling. Air quality prediction for fiture scenarios to 2030 is being facilitated by land use projections using a spatial growth model. Land use projections were developed using the 2030 Regional Transportation Plan developed by the Atlanta Regional Commission, the regional planning agency for the area. This allows the state Environmental Protection agency to evaluate how these

  9. Control strategies for sub-micrometer particles indoors: model study of air filtration and ventilation.

    PubMed

    Jamriska, M; Morawska, L; Ensor, D S

    2003-06-01

    The effects of air filtration and ventilation on indoor particles were investigated using a single-zone mathematical model. Particle concentration indoors was predicted for several I/O conditions representing scenarios likely to occur in naturally and mechanically ventilated buildings. The effects were studied for static and dynamic conditions in a hypothetical office building. The input parameters were based on real-world data. For conditions with high particle concentrations outdoors, it is recommended to reduce the amount of outdoor air delivered indoors and the necessary reduction level can be quantified by the model simulation. Consideration should also be given to the thermal comfort and minimum outdoor air required for occupants. For conditions dominated by an indoor source, it is recommended to increase the amount of outdoor air delivered indoors and to reduce the amount of return air. Air filtration and ventilation reduce particle concentrations indoors, with the overall effect depending on efficiency, location and the number of filters applied. The assessment of indoor air quality for specific conditions could be easily calculated by the model using user-defined input parameters.

  10. NEW DEVELOPMENTS IN THE COMMUNITY MULTISCALE AIR QUALITY (CMAQ) MODEL

    EPA Science Inventory

    CMAQ model research and development is currently following two tracks at the Atmospheric Modeling Division of the USEPA. Public releases of the community model system for research and policy analysis is continuing on an annual interval with the latest release scheduled for Augus...

  11. Stable isotope composition of waters in the Great Basin, United States 1. Air-mass trajectories

    USGS Publications Warehouse

    Friedman, I.; Harris, J.M.; Smith, G.I.; Johnson, C.A.

    2002-01-01

    Isentropic trajectories, calculated using the NOAA/Climate Monitoring and Diagnostics Laboratory's isentropic transport model, were used to determine air-parcel origins and the influence of air mass trajectories on the isotopic composition of precipitation events that occurred between October 1991 and September 1993 at Cedar City, Utah, and Winnemucca, Nevada. Examination of trajectories that trace the position of air parcels backward in time for 10 days indicated five distinct regions of water vapor origin: (1) Gulf of Alaska and North Pacific, (2) central Pacific, (3) tropical Pacific, (4) Gulf of Mexico, and (5) continental land mass. Deuterium (??D) and oxygen-18 (??18O) analyses were made of precipitation representing 99% of all Cedar City events. Similar analyses were made on precipitation representing 66% of the precipitation falling at Winnemucca during the same period. The average isotopic composition of precipitation derived from each water vapor source was determined. More than half of the precipitation that fell at both sites during the study period originated in the tropical Pacific and traveled northeast to the Great Basin; only a small proportion traversed the Sierra Nevada. The isotopic composition of precipitation is determined by air-mass origin and its track to the collection station, mechanism of droplet formation, reequilibration within clouds, and evaporation during its passage from cloud to ground. The Rayleigh distillation model can explain the changes in isotopic composition of precipitation as an air mass is cooled pseudo-adiabatically during uplift. However, the complicated processes that take place in the rapidly convecting environment of cumulonimbus and other clouds that are common in the Great Basin, especially in summer, require modification of this model because raindrops that form in the lower portion of those clouds undergo isotopic change as they are elevated to upper levels of the clouds from where they eventually drop to the

  12. Constraining Ammonia in Air Quality Models with Remote Sensing Observations and Inverse Modeling

    NASA Astrophysics Data System (ADS)

    Zhu, Liye

    Ammonia is an important species in the atmosphere as it contributes to air pollution, climate change and environmental health. Ammonia emissions are known to be primarily from agricultural sources, however there is persistent uncertainty in the magnitudes and seasonal trends of these sources, as ammonia has not traditionally been routinely monitored. The first detection of boundary layer ammonia from space by the NASA Tropospheric Emissions Spectrometer (TES) satellite has provided an exciting new means of reducing this uncertainty. In this thesis, I explore how forward and inverse modeling can be used with satellite observations to constrain ammonia emissions. Model simulations are used to build and validate the TES ammonia retrieval product. TES retrievals are then used to characterize global ammonia distributions and model estimates. Correlations between ammonia and carbon monoxide, observed simultaneously by TES, provide additional insight into observed and modeled ammonia from biomass burning. Next, through inverse modeling, I show that ammonia emissions are broadly underestimated throughout the U.S., particularly in the West. Optimized model simulations capture the range and variability of in-situ observation in April and October, while estimates in July are biased high. To understand these adjustments, several aspects of the retrieval are considered, such as spatial and temporal sampling biases. These investigations lead to revisions of fundamental aspects of how ammonia emissions are modeled, such as the diurnal variability of livestock ammonia emissions. While this improves comparison to hourly in situ measurements in the SE U.S., ammonia concentrations decrease throughout the globe, up to 17 ppb in India and Southeastern China. Lastly, the bi-directional air-surface exchange of ammonia is implemented for the first time in a global model and its adjoint. Ammonia bi-directional exchange generally increases ammonia gross emissions (10.9%) and surface

  13. Uncertainty characterization and quantification in air pollution models. Application to the CHIMERE model

    NASA Astrophysics Data System (ADS)

    Debry, Edouard; Mallet, Vivien; Garaud, Damien; Malherbe, Laure; Bessagnet, Bertrand; Rouïl, Laurence

    2010-05-01

    Prev'Air is the French operational system for air pollution forecasting. It is developed and maintained by INERIS with financial support from the French Ministry for Environment. On a daily basis it delivers forecasts up to three days ahead for ozone, nitrogene dioxide and particles over France and Europe. Maps of concentration peaks and daily averages are freely available to the general public. More accurate data can be provided to customers and modelers. Prev'Air forecasts are based on the Chemical Transport Model CHIMERE. French authorities rely more and more on this platform to alert the general public in case of high pollution events and to assess the efficiency of regulation measures when such events occur. For example the road speed limit may be reduced in given areas when the ozone level exceeds one regulatory threshold. These operational applications require INERIS to assess the quality of its forecasts and to sensitize end users about the confidence level. Indeed concentrations always remain an approximation of the true concentrations because of the high uncertainty on input data, such as meteorological fields and emissions, because of incomplete or inaccurate representation of physical processes, and because of efficiencies in numerical integration [1]. We would like to present in this communication the uncertainty analysis of the CHIMERE model led in the framework of an INERIS research project aiming, on the one hand, to assess the uncertainty of several deterministic models and, on the other hand, to propose relevant indicators describing air quality forecast and their uncertainty. There exist several methods to assess the uncertainty of one model. Under given assumptions the model may be differentiated into an adjoint model which directly provides the concentrations sensitivity to given parameters. But so far Monte Carlo methods seem to be the most widely and oftenly used [2,3] as they are relatively easy to implement. In this framework one

  14. Critical evaluation and modeling of algal harvesting using dissolved air flotation. DAF Algal Harvesting Modeling

    SciTech Connect

    Zhang, Xuezhi; Hewson, John C.; Amendola, Pasquale; Reynoso, Monica; Sommerfeld, Milton; Chen, Yongsheng; Hu, Qiang

    2014-07-14

    In our study, Chlorella zofingiensis harvesting by dissolved air flotation (DAF) was critically evaluated with regard to algal concentration, culture conditions, type and dosage of coagulants, and recycle ratio. Harvesting efficiency increased with coagulant dosage and leveled off at 81%, 86%, 91%, and 87% when chitosan, Al3+, Fe3+, and cetyl trimethylammonium bromide (CTAB) were used at dosages of 70, 180, 250, and 500 mg g-1, respectively. The DAF efficiency-coagulant dosage relationship changed with algal culture conditions. In evaluating the influence of the initial algal concentration and recycle ratio revealed that, under conditions typical for algal harvesting, we found that it is possible that the number of bubbles is insufficient. A DAF algal harvesting model was developed to explain this observation by introducing mass-based floc size distributions and a bubble limitation into the white water blanket model. Moreover, the model revealed the importance of coagulation to increase floc-bubble collision and attachment, and the preferential interaction of bubbles with larger flocs, which limited the availability of bubbles to the smaller sized flocs. The harvesting efficiencies predicted by the model agree reasonably with experimental data obtained at different Al3+ dosages, algal concentrations, and recycle ratios. Based on this modeling, critical parameters for efficient algal harvesting were identified.

  15. Critical evaluation and modeling of algal harvesting using dissolved air flotation. DAF Algal Harvesting Modeling

    DOE PAGES

    Zhang, Xuezhi; Hewson, John C.; Amendola, Pasquale; Reynoso, Monica; Sommerfeld, Milton; Chen, Yongsheng; Hu, Qiang

    2014-07-14

    In our study, Chlorella zofingiensis harvesting by dissolved air flotation (DAF) was critically evaluated with regard to algal concentration, culture conditions, type and dosage of coagulants, and recycle ratio. Harvesting efficiency increased with coagulant dosage and leveled off at 81%, 86%, 91%, and 87% when chitosan, Al3+, Fe3+, and cetyl trimethylammonium bromide (CTAB) were used at dosages of 70, 180, 250, and 500 mg g-1, respectively. The DAF efficiency-coagulant dosage relationship changed with algal culture conditions. In evaluating the influence of the initial algal concentration and recycle ratio revealed that, under conditions typical for algal harvesting, we found that itmore » is possible that the number of bubbles is insufficient. A DAF algal harvesting model was developed to explain this observation by introducing mass-based floc size distributions and a bubble limitation into the white water blanket model. Moreover, the model revealed the importance of coagulation to increase floc-bubble collision and attachment, and the preferential interaction of bubbles with larger flocs, which limited the availability of bubbles to the smaller sized flocs. The harvesting efficiencies predicted by the model agree reasonably with experimental data obtained at different Al3+ dosages, algal concentrations, and recycle ratios. Based on this modeling, critical parameters for efficient algal harvesting were identified.« less

  16. An Integrated Framework for Modeling Air Carrier Behavior, Policy, and Impacts in the U.S. Air Transportation System

    NASA Technical Reports Server (NTRS)

    Horio, Brant M.; Kumar, Vivek; DeCicco, Anthony H.; Hasan, Shahab; Stouffer, Virginia L.; Smith, Jeremy C.; Guerreiro, Nelson M.

    2015-01-01

    The implementation of the Next Generation Air Transportation System (NextGen) in the United States is an ongoing challenge for policymakers due to the complexity of the air transportation system (ATS) with its broad array of stakeholders and dynamic interdependencies between them. The successful implementation of NextGen has a hard dependency on the active participation of U.S. commercial airlines. To assist policymakers in identifying potential policy designs that facilitate the implementation of NextGen, the National Aeronautics and Space Administration (NASA) and LMI developed a research framework called the Air Transportation System Evolutionary Simulation (ATS-EVOS). This framework integrates large empirical data sets with multiple specialized models to simulate the evolution of the airline response to potential future policies and explore consequential impacts on ATS performance and market dynamics. In the ATS-EVOS configuration presented here, we leverage the Transportation Systems Analysis Model (TSAM), the Airline Evolutionary Simulation (AIRLINE-EVOS), the Airspace Concept Evaluation System (ACES), and the Aviation Environmental Design Tool (AEDT), all of which enable this research to comprehensively represent the complex facets of the ATS and its participants. We validated this baseline configuration of ATS-EVOS against Airline Origin and Destination Survey (DB1B) data and subject matter expert opinion, and we verified the ATS-EVOS framework and agent behavior logic through scenario-based experiments that explored potential implementations of a carbon tax, congestion pricing policy, and the dynamics for equipage of new technology by airlines. These experiments demonstrated ATS-EVOS's capabilities in responding to a wide range of potential NextGen-related policies and utility for decision makers to gain insights for effective policy design.

  17. Multi-scale modeling of urban air pollution: development of a Street-in-Grid model

    NASA Astrophysics Data System (ADS)

    Kim, Youngseob; Wu, You; Seigneur, Christian; Roustan, Yelva

    2016-04-01

    A new multi-scale model of urban air pollution is presented. This model combines a chemical-transport model (CTM) that includes a comprehensive treatment of atmospheric chemistry and transport at spatial scales greater than 1 km and a street-network model that describes the atmospheric concentrations of pollutants in an urban street network. The street-network model is based on the general formulation of the SIRANE model and consists of two main components: a street-canyon component and a street-intersection component. The street-canyon component calculates the mass transfer velocity at the top of the street canyon (roof top) and the mean wind velocity within the street canyon. The estimation of the mass transfer velocity depends on the intensity of the standard deviation of the vertical velocity at roof top. The effect of various formulations of this mass transfer velocity on the pollutant transport at roof-top level is examined. The street-intersection component calculates the mass transfer from a given street to other streets across the intersection. These mass transfer rates among the streets are calculated using the mean wind velocity calculated for each street and are balanced so that the total incoming flow rate is equal to the total outgoing flow rate from the intersection including the flow between the intersection and the overlying atmosphere at roof top. In the default option, the Leighton photostationary cycle among ozone (O3) and nitrogen oxides (NO and NO2) is used to represent the chemical reactions within the street network. However, the influence of volatile organic compounds (VOC) on the pollutant concentrations increases when the nitrogen oxides (NOx) concentrations are low. To account for the possible VOC influence on street-canyon chemistry, the CB05 chemical kinetic mechanism, which includes 35 VOC model species, is implemented in this street-network model. A sensitivity study is conducted to assess the uncertainties associated with the use of

  18. Combining regional- and local-scale air quality models with exposure models for use in environmental health studies.

    PubMed

    Isakov, Vlad; Touma, Jawad S; Burke, Janet; Lobdell, Danelle T; Palma, Ted; Rosenbaum, Arlene; Ozkaynak, Halûk

    2009-04-01

    Population-based human exposure models predict the distribution of personal exposures to pollutants of outdoor origin using a variety of inputs, including air pollution concentrations; human activity patterns, such as the amount of time spent outdoors versus indoors, commuting, walking, and indoors at home; microenvironmental infiltration rates; and pollutant removal rates in indoor environments. Typically, exposure models rely upon ambient air concentration inputs from a sparse network of monitoring stations. Here we present a unique methodology for combining multiple types of air quality models (the Community Multi-Scale Air Quality [CMAQ] chemical transport model added to the AERMOD dispersion model) and linking the resulting hourly concentrations to population exposure models (the Hazardous Air Pollutant Exposure Model [HAPEM] or the Stochastic Human Exposure and Dose Simulation [SHEDS] model) to enhance estimates of air pollution exposures that vary temporally (annual and seasonal) and spatially (at census-block-group resolution) in an urban area. The results indicate that there is a strong spatial gradient in the predicted mean exposure concentrations near roadways and industrial facilities that can vary by almost a factor of 2 across the urban area studied. At the high end of the exposure distribution (95th percentile), exposures are higher in the central district than in the suburbs. This is mostly due to the importance of personal mobility factors whereby individuals living in the central area often move between microenvironments with high concentrations, as opposed to individuals residing at the outskirts of the city. Also, our results indicate 20-30% differences due to commuting patterns and almost a factor of 2 difference because of near-roadway effects. These differences are smaller for the median exposures, indicating the highly variable nature of the reflected ambient concentrations. In conjunction with local data on emission sources

  19. Correlation of full-scale helicopter rotor performance in air with model-scale Freon data

    NASA Technical Reports Server (NTRS)

    Yeager, W. T., Jr.; Mantay, W. R.

    1976-01-01

    An investigation was conducted in a transonic dynamics tunnel to measure the performance of a 1/5 scale model helicopter rotor in a Freon atmosphere. Comparisons were made between these data and full scale data obtained in air. Both the model and full scale tests were conducted at advance ratios between 0.30 and 0.40 and advancing tip Mach numbers between 0.79 and 0.95. Results show that correlation of model scale rotor performance data obtained in Freon with full scale rotor performance data in air is good with regard to data trends. Mach number effects were found to be essentially the same for the model rotor performance data obtained in Freon and the full scale rotor performance data obtained in air. It was determined that Reynolds number effects may be of the same magnitude or smaller than rotor solidity effects or blade elastic modeling in rotor aerodynamic performance testing.

  20. Is it Necessary to Consider Air Flow in Land Surface Models

    NASA Astrophysics Data System (ADS)

    Zeng, Y.; Su, Z.; Wan, L.; Wen, J.

    2011-12-01

    From a subsurface physical point of view, this paper discusses the necessity and feasibility of considering two-phase heat and mass transfer process in land surface models (LSMs). The potential-based equations of coupled mass and heat transport under constant air pressure are adopted as the basis. The proposed model is developed on this basis by considering dry air as a single phase, and including mechanical dispersion in the water vapor and dry air transfer. The adsorbed liquid flux due to thermal gradient is also taken into account. The set of equations for the two-phase heat and mass transfer is formulated fully considering diffusion, advection and dispersion. The advantage of the proposed model over the traditional equation system is discussed. The accuracy of the proposed model is assessed through comparison with analytical work for coupled mass and heat transfer and experimental work for isothermal two-phase flow (moisture/air transfer). Further investigation is carried out to elucidate how the coupled moisture and heat transfer is influenced by adding the air flow, and how the isothermal two-phase flow is affected by considering the heat flow. The importance of including the air flow in the coupled mass and heat transfer is clearly identified. Concerning the two-phase flow, the influence of heat flow is only significant if the air phase plays a significant role in solving the equations of the water phase. Based on a field experiment, the proposed model is compared with the measured soil moisture, temperature and evaporation rate, the results show clearly that it is necessary to consider the air flow mechanism for soil-atmosphere interaction studies.

  1. Daily air quality forecast (gases and aerosols) over Switzerland. Modeling tool description and first results analysis.

    NASA Astrophysics Data System (ADS)

    Couach, O.; Kirchner, F.; Porchet, P.; Balin, I.; Parlange, M.; Balin, D.

    2009-04-01

    Map3D, the acronym for "Mesoscale Air Pollution 3D modelling", was developed at the EFLUM laboratory (EPFL) and received an INNOGRANTS awards in Summer 2007 in order to move from a research phase to a professional product giving daily air quality forecast. It is intended to give an objective base for political decisions addressing the improvement of regional air quality. This tool is a permanent modelling system which provides daily forecast of the local meteorology and the air pollutant (gases and particles) concentrations. Map3D has been successfully developed and calculates each day at the EPFL site a three days air quality forecast over Europe and the Alps with 50 km and 15 km resolution, respectively (see http://map3d.epfl.ch). The Map3D user interface is a web-based application with a PostgreSQL database. It is written in object-oriented PHP5 on a MVC (Model-View-Controller) architecture. Our prediction system is operational since August 2008. A first validation of the calculations for Switzerland is performed for the period of August 2008 - January 2009 comparing the model results for O3, NO2 and particulates with the results of the Nabel measurements stations. The subject of air pollution regimes (NOX/VOC) and specific indicators application with the forecast will be also addressed.

  2. Meteorological Modeling of Wintertime Cold Air Pool Stagnation Episodes in the Uintah and Salt Lake Basins

    NASA Astrophysics Data System (ADS)

    Crosman, E.; Horel, J.; Blaylock, B. K.; Foster, C.

    2014-12-01

    High wintertime ozone concentrations in rural areas associated with oil and gas development and high particulate concentrations in urban areas have become topics of increasing concern in the Western United States, as both primary and secondary pollutants become trapped within stable wintertime boundary layers. While persistent cold air pools that enable such poor wintertime air quality are typically associated with high pressure aloft and light winds, the complex physical processes that contribute to the formation, maintenance, and decay of persistent wintertime temperature inversions are only partially understood. In addition, obtaining sufficiently accurate numerical weather forecasts and meteorological simulations of cold air pools for input into chemical models remains a challenge. This study examines the meteorological processes associated with several wintertime pollution episodes in Utah's Uintah and Salt Lake Basins using numerical Weather Research and Forecasting model simulations and observations collected from the Persistent Cold Air Pool and Uintah Basin Ozone Studies. The temperature, vertical structure, and winds within these cold air pools was found to vary as a function of snow cover, snow albedo, land use, cloud cover, large-scale synoptic flow, and episode duration. We evaluate the sensitivity of key atmospheric features such as stability, planetary boundary layer depth, local wind flow patterns and transport mechanisms to variations in surface forcing, clouds, and synoptic flow. Finally, noted deficiencies in the meteorological models of cold air pools and modifications to the model snow and microphysics treatment that have resulted in improved cold pool simulations will be presented.

  3. Predicting residential air exchange rates from questionnaires and meteorology: model evaluation in central North Carolina.

    PubMed

    Breen, Michael S; Breen, Miyuki; Williams, Ronald W; Schultz, Bradley D

    2010-12-15

    A critical aspect of air pollution exposure models is the estimation of the air exchange rate (AER) of individual homes, where people spend most of their time. The AER, which is the airflow into and out of a building, is a primary mechanism for entry of outdoor air pollutants and removal of indoor source emissions. The mechanistic Lawrence Berkeley Laboratory (LBL) AER model was linked to a leakage area model to predict AER from questionnaires and meteorology. The LBL model was also extended to include natural ventilation (LBLX). Using literature-reported parameter values, AER predictions from LBL and LBLX models were compared to data from 642 daily AER measurements across 31 detached homes in central North Carolina, with corresponding questionnaires and meteorological observations. Data was collected on seven consecutive days during each of four consecutive seasons. For the individual model-predicted and measured AER, the median absolute difference was 43% (0.17 h(-1)) and 40% (0.17 h(-1)) for the LBL and LBLX models, respectively. Additionally, a literature-reported empirical scale factor (SF) AER model was evaluated, which showed a median absolute difference of 50% (0.25 h(-1)). The capability of the LBL, LBLX, and SF models could help reduce the AER uncertainty in air pollution exposure models used to develop exposure metrics for health studies.

  4. Coupled Air-Sea Observations and Modeling for Better Understanding Tropical Cyclone Prediction and Predictability

    NASA Astrophysics Data System (ADS)

    Chen, S. S.

    2014-12-01

    A systematic observational and modeling study is conducted to better understand the physical processes controlling air-sea interaction and their impact on tropical cyclone (TC) prediction and predictability using a fully coupled atmosphere-wave-ocean modeling system developed at the University of Miami and observations from field campaigns. We have developed a unified air-sea interface module that couples multiple atmosphere, wave, and ocean models using the Earth System Modeling Framework (ESMF). It is a physically based and computationally efficient coupling system that is flexible to use in a multi-model system and portable for transition to the next generation research and operational coupled atmosphere-wave-ocean-land models. This standardized coupling framework allows researchers to develop and test air-sea coupling parameterizations and coupled data assimilation, and to better facilitate research-to-operation activities. It also allows for ensemble forecasts that can be used for coupled atmosphere-ocean data assimilation and assessment of uncertainties in coupled model predictions. The coupled modeling system has been evaluated using the coupled air-sea observations (e.g., GPS dropsondes and AXBTs, ocean drifters and floats) collected in recent field campaigns in the Gulf of Mexico and TCs in the Atlantic and Pacific basins. This talk will provide 1) an overview of the unified air-sea interface model, 2) fully coupled atmosphere-wave-ocean model predictions of TCs and evaluation with coupled air-sea observations, and 3) results from high-resolution (1.3 km grid resolution) ensemble experiments using a stochastic kinetic energy backscatter (SKEB) perturbation method to assess the predictability and uncertainty in TC predictions.

  5. Emission inventories and modeling requirements for the development of air quality plans. Application to Madrid (Spain).

    PubMed

    Borge, Rafael; Lumbreras, Julio; Pérez, Javier; de la Paz, David; Vedrenne, Michel; de Andrés, Juan Manuel; Rodríguez, Ma Encarnación

    2014-01-01

    Modeling is an essential tool for the development of atmospheric emission abatement measures and air quality plans. Most often these plans are related to urban environments with high emission density and population exposure. However, air quality modeling in urban areas is a rather challenging task. As environmental standards become more stringent (e.g. European Directive 2008/50/EC), more reliable and sophisticated modeling tools are needed to simulate measures and plans that may effectively tackle air quality exceedances, common in large urban areas across Europe, particularly for NO₂. This also implies that emission inventories must satisfy a number of conditions such as consistency across the spatial scales involved in the analysis, consistency with the emission inventories used for regulatory purposes and versatility to match the requirements of different air quality and emission projection models. This study reports the modeling activities carried out in Madrid (Spain) highlighting the atmospheric emission inventory development and preparation as an illustrative example of the combination of models and data needed to develop a consistent air quality plan at urban level. These included a series of source apportionment studies to define contributions from the international, national, regional and local sources in order to understand to what extent local authorities can enforce meaningful abatement measures. Moreover, source apportionment studies were conducted in order to define contributions from different sectors and to understand the maximum feasible air quality improvement that can be achieved by reducing emissions from those sectors, thus targeting emission reduction policies to the most relevant activities. Finally, an emission scenario reflecting the effect of such policies was developed and the associated air quality was modeled.

  6. Material Properties from Air Puff Corneal Deformation by Numerical Simulations on Model Corneas

    PubMed Central

    Dorronsoro, Carlos; de la Hoz, Andrés; Marcos, Susana

    2016-01-01

    Objective To validate a new method for reconstructing corneal biomechanical properties from air puff corneal deformation images using hydrogel polymer model corneas and porcine corneas. Methods Air puff deformation imaging was performed on model eyes with artificial corneas made out of three different hydrogel materials with three different thicknesses and on porcine eyes, at constant intraocular pressure of 15 mmHg. The cornea air puff deformation was modeled using finite elements, and hyperelastic material parameters were determined through inverse modeling, minimizing the difference between the simulated and the measured central deformation amplitude and central-peripheral deformation ratio parameters. Uniaxial tensile tests were performed on the model cornea materials as well as on corneal strips, and the results were compared to stress-strain simulations assuming the reconstructed material parameters. Results The measured and simulated spatial and temporal profiles of the air puff deformation tests were in good agreement (< 7% average discrepancy). The simulated stress-strain curves of the studied hydrogel corneal materials fitted well the experimental stress-strain curves from uniaxial extensiometry, particularly in the 0–0.4 range. Equivalent Young´s moduli of the reconstructed material properties from air-puff were 0.31, 0.58 and 0.48 MPa for the three polymer materials respectively which differed < 1% from those obtained from extensiometry. The simulations of the same material but different thickness resulted in similar reconstructed material properties. The air-puff reconstructed average equivalent Young´s modulus of the porcine corneas was 1.3 MPa, within 18% of that obtained from extensiometry. Conclusions Air puff corneal deformation imaging with inverse finite element modeling can retrieve material properties of model hydrogel polymer corneas and real corneas, which are in good correspondence with those obtained from uniaxial extensiometry

  7. Inverse modelling of air quality data through a neural network approach

    NASA Astrophysics Data System (ADS)

    Russo, A.; Soares, A.; Trigo, R. M.; Pereira, M. J.

    2009-04-01

    Air quality is usually driven by a complex combination of factors where meteorology, physical obstacles and interaction between pollutants play significant roles. Considering the characteristics of the atmospheric circulation and also the residence times of certain pollutants in the atmosphere, air pollution is, nowadays, considered to be a global problem that affects everyone. As a result, a generalized and growing interest on air quality issues led to research intensification and publication of several articles with quite different levels of scientific depth. The main objective of this work is to produce an air quality model which allows forecasting critical concentration episodes of a certain pollutant by means of neural network modelling. In this paper, we describe the development of a neural network tool to forecast the daily average NO2 concentrations in Lisbon, Portugal, one day ahead. This research is based upon measurements from 22 air quality monitoring stations during the period 2001-2005. The analysis revealed that the most significant variable in predicting NO2 daily concentration is the previous day value of NO2 concentration followed by the 5a.m. NO2 concentration. This approach shows to be very promising for urban air quality characterization, allowing further developments in order to produce an integrated air quality and health surveillance/monitoring system in the area of Lisbon.

  8. Modeling validation and control analysis for controlled temperature and humidity of air conditioning system.

    PubMed

    Lee, Jing-Nang; Lin, Tsung-Min; Chen, Chien-Chih

    2014-01-01

    This study constructs an energy based model of thermal system for controlled temperature and humidity air conditioning system, and introduces the influence of the mass flow rate, heater and humidifier for proposed control criteria to achieve the controlled temperature and humidity of air conditioning system. Then, the reliability of proposed thermal system model is established by both MATLAB dynamic simulation and the literature validation. Finally, the PID control strategy is applied for controlling the air mass flow rate, humidifying capacity, and heating, capacity. The simulation results show that the temperature and humidity are stable at 541 sec, the disturbance of temperature is only 0.14 °C, 0006 kg(w)/kg(da) in steady-state error of humidity ratio, and the error rate is only 7.5%. The results prove that the proposed system is an effective controlled temperature and humidity of an air conditioning system.

  9. Modeling Validation and Control Analysis for Controlled Temperature and Humidity of Air Conditioning System

    PubMed Central

    Lee, Jing-Nang; Lin, Tsung-Min

    2014-01-01

    This study constructs an energy based model of thermal system for controlled temperature and humidity air conditioning system, and introduces the influence of the mass flow rate, heater and humidifier for proposed control criteria to achieve the controlled temperature and humidity of air conditioning system. Then, the reliability of proposed thermal system model is established by both MATLAB dynamic simulation and the literature validation. Finally, the PID control strategy is applied for controlling the air mass flow rate, humidifying capacity, and heating, capacity. The simulation results show that the temperature and humidity are stable at 541 sec, the disturbance of temperature is only 0.14°C, 0006 kgw/kgda in steady-state error of humidity ratio, and the error rate is only 7.5%. The results prove that the proposed system is an effective controlled temperature and humidity of an air conditioning system. PMID:25250390

  10. Photochemical Air Quality Modeling for California By U.S. EPA and Carb

    NASA Astrophysics Data System (ADS)

    Kelly, J.; Cai, C.; Baker, K. R.; Avise, J.; Kaduwela, A. P.

    2014-12-01

    Multiple areas of California have been designated as nonattainment of the National Ambient Air Quality Standards (NAAQS) for ozone and PM2.5 (particulate matter with aerodynamic diameter < 2.5 microns). Air quality modeling plays a key role in developing emission control strategies for attaining the NAAQS in these regions and for estimating the incremental costs and benefits of meeting new NAAQS levels. The complex terrain, meteorology, emissions, and chemistry in California present challenges to such air quality modeling. In this study, we improve understanding of modeling approaches for California by comparing and evaluating predictions of the Community Multiscale Air Quality (CMAQ) model as configured by the California Air Resources Board (CARB) and the U.S. Environmental Protection Agency (EPA). Both simulations were conducted at 4-km horizontal resolution and cover the May-June 2010 period when special study measurements were made. Despite differences in emissions, meteorology, boundary conditions, and chemical mechanisms, the CMAQ predictions by EPA and CARB were generally similar with good model performance for ozone at key monitors. Differences in predictions for PM2.5 components were identified in some locations and attributed to differences in emissions and other platform elements. Our results suggest areas where model development would be beneficial.

  11. The effects of advection solvers on the performance of air quality models

    SciTech Connect

    Tanrikulu, S.; Odman, M.T.

    1996-12-31

    The available numerical solvers for the advection term in the chemical species conservation equation have different properties, and consequently introduce different types of errors. These errors can affect the performance of air quality models and lead to biases in model results. In this study, a large number of advection solvers have been studied and six of them were identified as having potential for use in photochemical models. The identified solvers were evaluated extensively using various numerical tests that are relevant to air quality simulations. Among the solvers evaluated, three of them showed better performance in terms of accuracy and some other characteristics such as conservation of mass and positivity. They are the solvers by Bott, Yuamartino, and Dabdub and Seinfeld. These three solvers were incorporated into the SARMAP Air Quality Model (SAQM) and the August 3-6, 1990 ozone episode in the San Joaquin Valley of California was simulated with each. A model performance analysis was conducted for each simulation using the rich air quality database of the 1990 San Joaquin Valley Air Quality Study. The results of the simulations were compared with each other and the effects of advection solvers on the performance of the model are discussed.

  12. Validation of a CFD model by using 3D sonic anemometers to analyse the air velocity generated by an air-assisted sprayer equipped with two axial fans.

    PubMed

    García-Ramos, F Javier; Malón, Hugo; Aguirre, A Javier; Boné, Antonio; Puyuelo, Javier; Vidal, Mariano

    2015-01-22

    A computational fluid dynamics (CFD) model of the air flow generated by an air-assisted sprayer equipped with two axial fans was developed and validated by practical experiments in the laboratory. The CFD model was developed by considering the total air flow supplied by the sprayer fan to be the main parameter, rather than the outlet air velocity. The model was developed for three air flows corresponding to three fan blade settings and assuming that the sprayer is stationary. Actual measurements of the air velocity near the sprayer were taken using 3D sonic anemometers. The workspace sprayer was divided into three sections, and the air velocity was measured in each section on both sides of the machine at a horizontal distance of 1.5, 2.5, and 3.5 m from the machine, and at heights of 1, 2, 3, and 4 m above the ground The coefficient of determination (R2) between the simulated and measured values was 0.859, which demonstrates a good correlation between the simulated and measured data. Considering the overall data, the air velocity values produced by the CFD model were not significantly different from the measured values.

  13. Validation of a CFD Model by Using 3D Sonic Anemometers to Analyse the Air Velocity Generated by an Air-Assisted Sprayer Equipped with Two Axial Fans

    PubMed Central

    García-Ramos, F. Javier; Malón, Hugo; Aguirre, A. Javier; Boné, Antonio; Puyuelo, Javier; Vidal, Mariano

    2015-01-01

    A computational fluid dynamics (CFD) model of the air flow generated by an air-assisted sprayer equipped with two axial fans was developed and validated by practical experiments in the laboratory. The CFD model was developed by considering the total air flow supplied by the sprayer fan to be the main parameter, rather than the outlet air velocity. The model was developed for three air flows corresponding to three fan blade settings and assuming that the sprayer is stationary. Actual measurements of the air velocity near the sprayer were taken using 3D sonic anemometers. The workspace sprayer was divided into three sections, and the air velocity was measured in each section on both sides of the machine at a horizontal distance of 1.5, 2.5, and 3.5 m from the machine, and at heights of 1, 2, 3, and 4 m above the ground The coefficient of determination (R2) between the simulated and measured values was 0.859, which demonstrates a good correlation between the simulated and measured data. Considering the overall data, the air velocity values produced by the CFD model were not significantly different from the measured values. PMID:25621611

  14. NEW CATEGORICAL METRICS FOR AIR QUALITY MODEL EVALUATION

    EPA Science Inventory

    Traditional categorical metrics used in model evaluations are "clear-cut" measures in that the model's ability to predict an exceedance is defined by a fixed threshold concentration and the metrics are defined by observation-forecast sets that are paired both in space and time. T...

  15. Effects of Humidity Swings on Adsorption Columns for Air Revitalization: Modeling and Experiments

    NASA Technical Reports Server (NTRS)

    LeVan, M. Douglas; Finn, John E.

    1997-01-01

    Air purification systems are necessary to provide clean air in the closed environments aboard spacecraft. Trace contaminants are removed using adsorption. One major factor concerning the removal of trace contaminants is relative humidity. Water can reduce adsorption capacity and, due to constant fluctuations, its presence is difficult to incorporate into adsorption column designs. The purpose of the research was to allow for better design techniques in trace contaminant adsorption systems, especially for feeds with water present. Experiments and mathematical modeling research on effects of humidity swings on adsorption columns for air revitalization were carried out.

  16. A spatial multicriteria model for determining air pollution at sample locations.

    PubMed

    Réquia Júnior, Weeberb João; Roig, Henrique Llacer; Koutrakis, Petros

    2015-02-01

    Atmospheric pollution in urban centers has been one of the main causes of human illness related to the respiratory and circulatory system. Efficient monitoring of air quality is a source of information for environmental management and public health. This study investigates the spatial patterns of atmospheric pollution using a spatial multicriteria model that helps target locations for air pollution monitoring sites. The main objective was to identify high-priority areas for measuring human exposures to air pollutants as they relate to emission sources. The method proved to be viable and flexible in its application to various areas.

  17. Which model better fits the role of aire in the establishment of self-tolerance: the transcription model or the maturation model?

    PubMed

    Matsumoto, Mitsuru; Nishikawa, Yumiko; Nishijima, Hitoshi; Morimoto, Junko; Matsumoto, Minoru; Mouri, Yasuhiro

    2013-01-01

    The discovery of Aire-dependent transcriptional control of many tissue-restricted self-antigen (TRA) genes in thymic epithelial cells in the medulla (medullary thymic epithelial cells, mTECs) has raised the intriguing question of how the single Aire gene can influence the transcription of such a large number of TRA genes within mTECs. From a mechanistic viewpoint, there are two possible models to explain the function of Aire in this action. In the first model, TRAs are considered to be the direct target genes of Aire's transcriptional activity. In this scenario, the lack of Aire protein within cells would result in the defective TRA gene expression, while the maturation program of mTECs would be unaffected in principle. The second model hypothesizes that Aire is necessary for the maturation program of mTECs. In this case, we assume that the mTEC compartment does not mature normally in the absence of Aire. If acquisition of the properties of TRA gene expression depends on the maturation status of mTECs, a defect of such an Aire-dependent maturation program in Aire-deficient mTECs can also result in impaired TRA gene expression. In this brief review, we will focus on these two contrasting models for the roles of Aire in controlling the expression of TRAs within mTECs.

  18. Vanadium inhalation in a mouse model for the understanding of air-suspended particle systemic repercussion.

    PubMed

    Fortoul, T I; Rodriguez-Lara, V; Gonzalez-Villalva, A; Rojas-Lemus, M; Cano-Gutierrez, G; Ustarroz-Cano, M; Colin-Barenque, L; Montaño, L F; García-Pelez, I; Bizarro-Nevares, P; Lopez-Valdez, N; Falcon-Rodriguez, C I; Jimenez-Martínez, R S; Ruiz-Guerrero, M L; López-Zepeda, L S; Morales-Rivero, A; Muñiz-Rivera-Cambas, A

    2011-01-01

    There is an increased concern about the health effects that air-suspended particles have on human health which have been dissected in animal models. Using CD-1 mouse, we explore the effects that vanadium inhalation produce in different tissues and organs. Our findings support the systemic effects of air pollution. In this paper, we describe our findings in different organs in our conditions and contrast our results with the literature. PMID:21716674

  19. The comfort and satisfaction of air travelers - Basis for a descriptive model

    NASA Technical Reports Server (NTRS)

    Jacobson, I. D.; Martinez, J.

    1974-01-01

    The results of a questionnaire and interview survey are used as a basis for proposing a descriptive model of the comfort and satisfaction of the commercial air traveler. Passenger attitudes toward the present commercial air travel system are examined. Comfort is interpreted as being represented by a four-dimensional composite of commonly encountered environmental variables. Satisfaction is represented as a composite of safety, cost-benefit, luxury, and in-flight activity dimensions.

  20. Vanadium Inhalation in a Mouse Model for the Understanding of Air-Suspended Particle Systemic Repercussion

    PubMed Central

    Fortoul, T. I.; Rodriguez-Lara, V.; Gonzalez-Villalva, A.; Rojas-Lemus, M.; Cano-Gutierrez, G.; Ustarroz-Cano, M.; Colin-Barenque, L.; Montaño, L. F.; García-Pelez, I.; Bizarro-Nevares, P.; Lopez-Valdez, N.; Falcon-Rodriguez, C. I.; Jimenez-Martínez, R. S.; Ruiz-Guerrero, M. L.; López-Zepeda, L. S.; Morales-Rivero, A.; Muñiz-Rivera-Cambas, A.

    2011-01-01

    There is an increased concern about the health effects that air-suspended particles have on human health which have been dissected in animal models. Using CD-1 mouse, we explore the effects that vanadium inhalation produce in different tissues and organs. Our findings support the systemic effects of air pollution. In this paper, we describe our findings in different organs in our conditions and contrast our results with the literature. PMID:21716674

  1. Modeling the ascent of sounding balloons: derivation of the vertical air motion

    NASA Astrophysics Data System (ADS)

    Gallice, A.; Wienhold, F. G.; Hoyle, C. R.; Immler, F.; Peter, T.

    2011-06-01

    A new model to describe the ascent of sounding balloons in the troposphere and lower stratosphere (up to ~30-35 km altitude) is presented. Contrary to previous models, detailed account is taken of both the variation of the drag coefficient with altitude and the heat imbalance between the balloon and the atmosphere. To compensate for the lack of data on the drag coefficient of sounding balloons, a reference curve for the relationship between drag coefficient and Reynolds number is derived from a dataset of flights launched during the Lindenberg Upper Air Methods Intercomparisons (LUAMI) campaign. The transfer of heat from the surrounding air into the balloon is accounted for by solving the radial heat diffusion equation inside the balloon. The potential applications of the model include the forecast of the trajectory of sounding balloons, which can be used to increase the accuracy of the match technique, and the derivation of the air vertical velocity. The latter is obtained by subtracting the ascent rate of the balloon in still air calculated by the model from the actual ascent rate. This technique is shown to provide an approximation for the vertical air motion with an uncertainty error of 0.5 m s-1 in the troposphere and 0.2 m s-1 in the stratosphere. An example of extraction of the air vertical velocity is provided in this paper. We show that the air vertical velocities derived from the balloon soundings in this paper are in general agreement with small-scale atmospheric velocity fluctuations related to gravity waves, mechanical turbulence, or other small-scale air motions measured during the SUCCESS campaign (Subsonic Aircraft: Contrail and Cloud Effects Special Study) in the orographically unperturbed mid-latitude middle troposphere.

  2. Environmental baseline survey report for West Black Oak Ridge, East Black Oak Ridge, McKinney Ridge, West Pine Ridge and parcel 21D in the vicinity of the East Technology Park, Oak Ridge, Tennessee

    SciTech Connect

    King, David A.

    2012-11-29

    This environmental baseline survey (EBS) report documents the baseline environmental conditions of five land parcels located near the U.S. Department of Energy?s (DOE?s) East Tennessee Technology Park (ETTP), including West Black Oak Ridge, East Black Oak Ridge, McKinney Ridge, West Pine Ridge, and Parcel 21d. Preparation of this report included the detailed search of federal government records, title documents, aerial photos that may reflect prior uses, and visual inspections of the property and adjacent properties. Interviews with current employees involved in, or familiar with, operations on the real property were also conducted to identify any areas on the property where hazardous substances and petroleum products, or their derivatives, and acutely hazardous wastes may have been released or disposed. In addition, a search was made of reasonably obtainable federal, state, and local government records of each adjacent facility where there has been a release of any hazardous substance or any petroleum product or their derivatives, including aviation fuel and motor oil, and which is likely to cause or contribute to a release of any hazardous substance or any petroleum product or its derivatives, including aviation fuel or motor oil, on the real property. A radiological survey and soil/sediment sampling was conducted to assess baseline conditions of Parcel 21d that were not addressed by the soils-only no-further-investigation (NFI) reports. Groundwater sampling was also conducted to support a Parcel 21d decision. Based on available data West Black Oak Ridge, East Black Oak Ridge, McKinney Ridge, and West Pine Ridge are not impacted by site operations and are not subject to actions per the Federal Facility Agreement (FFA). This determination is supported by visual inspections, records searches and interviews, groundwater conceptual modeling, approved NFI reports, analytical data, and risk analysis results. Parcel 21d data, however, demonstrate impacts from site

  3. Laryngeal Cuff Force Application Modeling During Air Medical Evacuation Simulation.

    PubMed

    Eisenbrey, David; Eisenbrey, Arthur B; Pettengill, Patrick

    2016-01-01

    Endotracheal tubes are intended to protect the airway and assist with mechanical ventilation in sedated patients. The blood vessels of the tracheal mucosa can be compressed by high tracheal tube cuff pressures (> 30 cm H2O), leading to reduced mucosal blood flow with resulting ischemia and morbidity. Previous research showed a direct correlation between aircraft pressure altitude and the pressure reading from the tracheal cuff, with resulting pressures > 80 cm H2O at 10,000 ft. Standard practice is to periodically remove air from the cuff during ascent based on assumed increased pressure on the adjacent tracheal mucosa. Using a vacuum chamber and a direct reading micropressure sensor in a 22-mm-diameter semirigid tube, we assessed the direct force applied by the tracheal cuff against the laryngeal tube analog. Standard tracheal cuffs showed direct force/pressure relationships when properly inflated to 20 cm H2O but much less than reported in the literature. Current literature reports values of 55 to 150 cm H2O at 5,000 ft, whereas we report 23 to 25 cm H2O. Our data indicate that a properly inflated cuff does not exceed the critical pressure of 30 cm H2O until the altitude exceeds 8,000 ft. Thus, the standard practice of deflating the laryngeal cuff on ascent should be reconsidered because it may be counterproductive to patient safety. PMID:27637439

  4. Tracking hazardous air pollutants from a refinery fire by applying on-line and off-line air monitoring and back trajectory modeling.

    PubMed

    Shie, Ruei-Hao; Chan, Chang-Chuan

    2013-10-15

    The air monitors used by most regulatory authorities are designed to track the daily emissions of conventional pollutants and are not well suited for measuring hazardous air pollutants that are released from accidents such as refinery fires. By applying a wide variety of air-monitoring systems, including on-line Fourier transform infrared spectroscopy, gas chromatography with a flame ionization detector, and off-line gas chromatography-mass spectrometry for measuring hazardous air pollutants during and after a fire at a petrochemical complex in central Taiwan on May 12, 2011, we were able to detect significantly higher levels of combustion-related gaseous and particulate pollutants, refinery-related hydrocarbons, and chlorinated hydrocarbons, such as 1,2-dichloroethane, vinyl chloride monomer, and dichloromethane, inside the complex and 10 km downwind from the fire than those measured during the normal operation periods. Both back trajectories and dispersion models further confirmed that high levels of hazardous air pollutants in the neighboring communities were carried by air mass flown from the 22 plants that were shut down by the fire. This study demonstrates that hazardous air pollutants from industrial accidents can successfully be identified and traced back to their emission sources by applying a timely and comprehensive air-monitoring campaign and back trajectory air flow models. PMID:23912073

  5. AN INDOOR PESTICIDE AIR AND SURFACE CONCENTRATION MODEL

    EPA Science Inventory

    A thorough assessment of human exposure to environmental chemicals requires consideration of all processes in the sequence from source to dose. For assessment of exposure to pesticides following their use indoors, data and models are needed to estimate pesticide concentrations...

  6. SUMMARY REPORT OF AIR QUALITY MODELING RESEARCH ACTIVITIES FOR 2006

    EPA Science Inventory

    Through a Memorandum of Understanding (MOU) and Memorandum of Agreement (MOA) between the Department of Commerce (DOC) and U.S. Environmental Protection Agency (EPA), the Atmospheric Sciences Modeling Division (ASMD) of National Oceanic and Atmospheric Administration's (NOAA's) ...

  7. Model Of Orbital Density Of Air For Computing Drag

    NASA Technical Reports Server (NTRS)

    Lear, W. M.

    1990-01-01

    Simple, Orbital Density Model for Drag Equations program useful for computing effect of drag over one or more orbits. Mathematical model embodied in program incorporates major changes in density due to solar activity and magnetic activity of Earth. Diurnal (day/night) effects on orbit averaged out. Based on Jacchia daily-average density, evaluated at average time of year. Advantages, right ascension and declination of Sun not needed and computation time much reduced. Written in FORTRAN 77.

  8. Modeling of Air Attenuation Effects on Gamma Detection at Altitude

    SciTech Connect

    R. S. Detwiler

    2002-10-01

    This paper focuses on modeling the detection capabilities of NaI sensor systems at high altitudes for ground sources. The modeling was done with the Monte Carlo N-Transport (MCNP) code developed at Los Alamos National Laboratory. The specific systems modeled were the fixed wing and helicopter aircraft sensor systems, assets of the U. S. Department of Energy's National Nuclear Security Administration Nevada Operations Office (NNSA/NV) Aerial Measuring System (AMS). In previous (2001) modeling, Sodium Iodine (NaI) detector responses were simulated for both point and distributed surface sources as a function of gamma energy and altitude. For point sources, photo-peak efficiencies were calculated for a zero radial distance and an offset equal to the altitude. For distributed sources approximating an infinite plane, gross count efficiencies were calculated and normalized to a uniform surface deposition of 1 {micro}Ci/m{sup 2}. To validate the calculations, benchmark measurements were made for simple source-detector configurations. The 2002 continuation of the modeling presented here includes checking models against available data, and modifications to allow more effective and accurate directional biasing of ground point and distributed sources. Fixed-wing data results will be shown for two point sources as a function of altitude.

  9. Air-climate-energy investigations with a state-level Integrated Assessment Model: GCAM-USA

    EPA Science Inventory

    The Global Change Assessment Model (GCAM) is a global integrated assessment model used for exploring future scenarios and examining strategies that address air pollution, climate change, and energy goals.  GCAM includes technology-rich representations of the energy, transportatio...

  10. The Impact of the Developmental Training Model on Staff Development in Air Force Child Development Programs

    ERIC Educational Resources Information Center

    Bird, Candace Maria Edmonds

    2010-01-01

    In an effort to standardize training delivery and to individualize staff development based on observation and reflective practice, the Air Force implemented the Developmental Training Model (DTM) in its Child Development Programs. The goal of the Developmental Training Model is to enhance high quality programs through improvements in the training…

  11. A model to predict the removal of oxygen from air using a zirconia solid electrolyte membrane

    NASA Technical Reports Server (NTRS)

    Marner, W. J.; Suitor, J. W.; Glazer, C. R.

    1988-01-01

    A finite difference mathematical model has been developed to predict the removal of oxygen from air using a zirconia separation cell. The model predicts the electrical and mass transfer processes in circular disk cells with either axial or radial current flow in the electrodes and in tubular cells with axial current flow in the electrodes. Representative results are presented and discussed.

  12. Simulation of population-based commuter exposure to NO₂ using different air pollution models.

    PubMed

    Ragettli, Martina S; Tsai, Ming-Yi; Braun-Fahrländer, Charlotte; de Nazelle, Audrey; Schindler, Christian; Ineichen, Alex; Ducret-Stich, Regina E; Perez, Laura; Probst-Hensch, Nicole; Künzli, Nino; Phuleria, Harish C

    2014-05-12

    We simulated commuter routes and long-term exposure to traffic-related air pollution during commute in a representative population sample in Basel (Switzerland), and evaluated three air pollution models with different spatial resolution for estimating commute exposures to nitrogen dioxide (NO2) as a marker of long-term exposure to traffic-related air pollution. Our approach includes spatially and temporally resolved data on actual commuter routes, travel modes and three air pollution models. Annual mean NO2 commuter exposures were similar between models. However, we found more within-city and within-subject variability in annual mean (±SD) NO2 commuter exposure with a high resolution dispersion model (40 ± 7 µg m(-3), range: 21-61) than with a dispersion model with a lower resolution (39 ± 5 µg m(-3); range: 24-51), and a land use regression model (41 ± 5 µg m(-3); range: 24-54). Highest median cumulative exposures were calculated along motorized transport and bicycle routes, and the lowest for walking. For estimating commuter exposure within a city and being interested also in small-scale variability between roads, a model with a high resolution is recommended. For larger scale epidemiological health assessment studies, models with a coarser spatial resolution are likely sufficient, especially when study areas include suburban and rural areas.

  13. Simulation of Population-Based Commuter Exposure to NO2 Using Different Air Pollution Models

    PubMed Central

    Ragettli, Martina S.; Tsai, Ming-Yi; Braun-Fahrländer, Charlotte; de Nazelle, Audrey; Schindler, Christian; Ineichen, Alex; Ducret-Stich, Regina E.; Perez, Laura; Probst-Hensch, Nicole; Künzli, Nino; Phuleria, Harish C.

    2014-01-01

    We simulated commuter routes and long-term exposure to traffic-related air pollution during commute in a representative population sample in Basel (Switzerland), and evaluated three air pollution models with different spatial resolution for estimating commute exposures to nitrogen dioxide (NO2) as a marker of long-term exposure to traffic-related air pollution. Our approach includes spatially and temporally resolved data on actual commuter routes, travel modes and three air pollution models. Annual mean NO2 commuter exposures were similar between models. However, we found more within-city and within-subject variability in annual mean (±SD) NO2 commuter exposure with a high resolution dispersion model (40 ± 7 µg m−3, range: 21–61) than with a dispersion model with a lower resolution (39 ± 5 µg m−3; range: 24–51), and a land use regression model (41 ± 5 µg m−3; range: 24–54). Highest median cumulative exposures were calculated along motorized transport and bicycle routes, and the lowest for walking. For estimating commuter exposure within a city and being interested also in small-scale variability between roads, a model with a high resolution is recommended. For larger scale epidemiological health assessment studies, models with a coarser spatial resolution are likely sufficient, especially when study areas include suburban and rural areas. PMID:24823664

  14. Verification and uses of the Environmental Protection Agency (EPA) indoor air quality model

    SciTech Connect

    Sparks, L.E.; Tichenor, B.A.; Jackson, M.D.; White, J.B.

    1989-01-01

    The paper describes a set of experiments used to verify an indoor air quality (IAQ) model for estimating the impact of various pollution sources on IAQ in a multiroom building. The model treats each room as a well-mixed chamber that contains pollution sources and sinks. The model allows analysis of the impact of room-to-room air flows, HVAC (heating, ventilating, and air-conditioning) systems, and air cleaners on IAQ. The model is written for personal computers. The experiments were conducted in a test house. Three pollution sources were used: moth crystals, kerosene heaters, and dry cleaned cloths. The model predictions were in good agreement with the experimental data, especially when a sink term was included in the model. The paper gives a brief discussion of the theory on which the model is based. Preliminary data and theory of sources and sinks are also discussed. Examples demonstrating the use of the model to analyze IAQ options and to estimate exposure from a pollutant are included.

  15. Incremental Testing of the Community Multiscale Air Quality (CMAQ) Modeling System Version 4.7

    EPA Science Inventory

    This paper describes the scientific and structural updates to the latest release of the Community Multiscale Air Quality (CMAQ) modeling system version 4.7 (v4.7) and points the reader to additional resources for further details. The model updates were evaluated relative to obse...

  16. 40 CFR Appendix W to Part 51 - Guideline on Air Quality Models

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... quality models in response to regulatory requirements and the expanded requirements for models to cover....0Bibliography 12.0References Appendix A to Appendix W of 40 CFR Part 51—Summaries of Preferred Air Quality... assessing source impact and in evaluating control strategies. i. Appendix W to 40 CFR Part 51...

  17. A modeling framework for characterizing near-road air pollutant concentration at community scales

    EPA Science Inventory

    In this study, we combine information from transportation network, traffic emissions, and dispersion model to develop a framework to inform exposure estimates for traffic-related air pollutants (TRAPs) with a high spatial resolution. A Research LINE source dispersion model (R-LIN...

  18. SYSTEMIC BIOMARKERS AND CARDIAC GENE EXPRESSION PROFILES OF RAT DISEASE MODELS EMPLOYED IN AIR POLLUTION STUDIES

    EPA Science Inventory

    Cardiovascular disease (CVD) models are used for identification of mechanisms of susceptibility to air pollution. We hypothesized that baseline systemic biomarkers and cardiac gene expression in CVD rat models will have influence on their ozone-induced lung inflammation. Male 12-...

  19. The Danish eulerian hemispheric model — a three-dimensional air pollution model used for the arctic

    NASA Astrophysics Data System (ADS)

    Christensen, Jesper Heile

    A three-dimensional Eulerian hemispheric air pollution model, the Danish Eulerian Hemispheric Model (DEHM), is in development at the National Environmental Research Institute (NERI). The model has been used to study long-range transport of air pollution in the Northern Hemisphere. The present version of the model includes long-range transport of sulphur dioxide (SO 2) and particulate sulphate (SC 42-. The chemistry in the model is described by a simple linear oxidation of SO 2 to SO 42-, and the wet deposition of SO 2 and SO 4- is estimated based on the amount of precipitation, which is calculated from the contents of liquid cloud water (see Christensen, Air Pollution Modelling and its Applicatioons, Vol. X, pp. 119-127, Vol. XI, pp. 249-256, Plenum press, New York; 1995, Ph.D. thesis, National Environmental Research Institute, Denmark). The model has been used to study the air pollution in the Arctic. Results from 3 1/2 yr simulation with an analysis of the results is presented: the model results are verified by comparisons, to measurements not only from the Arctic region but also from Europe and Canada. Some examples of episodes in the Arctic including analysis of the meteorological conditions during the episodes are presented. Finally, the model has been used to estimate the contribution from the different source regions on the northern hemisphere to the Arctic sulphur pollution.

  20. Occupant exposure to indoor air pollutants in modern European offices: An integrated modelling approach

    NASA Astrophysics Data System (ADS)

    Terry, Andrew C.; Carslaw, Nicola; Ashmore, Mike; Dimitroulopoulou, Sani; Carslaw, David C.

    2014-01-01

    A new model (INDAIR-CHEM) has been developed by combining a detailed indoor air chemistry model with a physical and probabilistic multi-compartment indoor/outdoor air exposure model. The detailed indoor air chemistry model was used to produce a simplified chemistry scheme for INDAIR-CHEM, which performs well for key indoor air pollutants under a range of conditions when compared to the parent model. INDAIR-CHEM was used to compare indoor pollutant concentrations in naturally ventilated offices in 8 European cities for typical outdoor conditions in summer, with those experienced during the European heat-wave in August 2003 for different air exchange rates. We also investigated the effect of cleaning with limonene based products on the subsequent exposure to secondary reaction products from limonene degradation. Extreme climatic conditions, such as a heat-wave which often leads to poor outdoor air quality, can increase personal exposure to both primary and secondary species indoors. Occupant exposure to indoor air pollutants may also be exacerbated by poor ventilation in offices. Reduced ventilation reduces maximum exposure to ozone, as there is less ingress from outdoors, but allows secondary species to persist indoors for much longer. The balance between these two processes may mean that cumulative exposures for office workers increase as ventilation decreases. Cleaning staff are at lower risk of exposure to secondary oxidation products if they clean before office hours rather than after office hours, since ozone is generally at lower outdoor (and hence indoor) concentrations during the early morning compared to late afternoon. However, from the viewpoint of office workers, reduced exposure would occur if cleaning was performed at the end of the working day.

  1. Air pollution modeling at road sides using the operational street pollution model--a case study in Hanoi, Vietnam.

    PubMed

    Hung, Ngo Tho; Ketzel, Matthias; Jensen, Steen Solvang; Oanh, Nguyen Thi Kim

    2010-11-01

    In many metropolitan areas, traffic is the main source of air pollution. The high concentrations of pollutants in streets have the potential to affect human health. Therefore, estimation of air pollution at the street level is required for health impact assessment. This task has been carried out in many developed countries by a combination of air quality measurements and modeling. This study focuses on how to apply a dispersion model to cities in the developing world, where model input data and data from air quality monitoring stations are limited or of varying quality. This research uses the operational street pollution model (OSPM) developed by the National Environmental Research Institute in Denmark for a case study in Hanoi, the capital of Vietnam. OSPM predictions from five streets were evaluated against air pollution measurements of nitrogen oxides (NO(x)), sulfur dioxide (SO2), carbon monoxide (CO), and benzene (BNZ) that were available from previous studies. Hourly measurements and passive sample measurements collected over 3-week periods were compared with model outputs, applying emission factors from previous studies. In addition, so-called "backward calculations" were performed to adapt the emission factors for Hanoi conditions. The average fleet emission factors estimated can be used for emission calculations at other streets in Hanoi and in other locations in Southeast Asia with similar vehicle types. This study also emphasizes the need to further eliminate uncertainties in input data for the street-scale air pollution modeling in Vietnam, namely by providing reliable emission factors and hourly air pollution measurements of high quality.

  2. Programs Model the Future of Air Traffic Management

    NASA Technical Reports Server (NTRS)

    2010-01-01

    Through Small Business Innovation Research (SBIR) contracts with Ames Research Center, Intelligent Automation Inc., based in Rockville, Maryland, advanced specialized software the company had begun developing with U.S. Department of Defense funding. The agent-based infrastructure now allows NASA's Airspace Concept Evaluation System to explore ways of improving the utilization of the National Airspace System (NAS), providing flexible modeling of every part of the NAS down to individual planes, airports, control centers, and even weather. The software has been licensed to a number of aerospace and robotics customers, and has even been used to model the behavior of crowds.

  3. Air-dispersion modeling and the real world

    SciTech Connect

    Beychok, M.T.

    1996-06-01

    Use of computerized programs to model stack-gas dispersion mathematically has grown immensely in the last 15 years. In most dispersion models, determining ground-level pollutant concentrations beneath an elevated, buoyant plume of dispersing stack gas involves two major steps. First, the height to which the plume rises at a given downward distance from the plume source is calculated. The calculated plume rise is added to the height of the source stack, or emission point, to determine the effective stack height, also called the plume centerline height. Second, ground-level concentrations beneath the plume are predicted using the Gaussian dispersion equation.

  4. Multiscale air quality modeling of the Northeastern United States

    NASA Astrophysics Data System (ADS)

    Kumar, Naresh; Russell, Armistead G.

    The Urban and Regional Multiscale (URM) model has been used to study the ozone problem in the northeastern United States. The model was applied to a multiday ozone episode extending from 2 July 1988 to 8 July 1988. The URM model is particularly suitable for application to the Northeast as there is a dense network of urban centers along with large rural areas, and the model allows the use of variable grid sizes to effectively capture the pollutant dynamics while being computationally efficient. This study particularly concentrates on how spatial grid resolution affects results, particularly in the Northeast Corridor, a string of urban centers extending from Washington D.C. to Boston. Three different grid systems are employed in the model simulations to examine this issue. The most dynamic grid system uses grid sizes varying from 4.625 to 74 km, with the finest grids concentrated in the Northeast Corridor. The uniform grid system uses a uniform grid size of 18.5 km similar to that used in the regional oxidant model (ROM). The intermediate grid system uses grid sizes varying from 4.625 to 18.5 km. When finer grids are used over the urban areas, as in the intermediate and the most dynamic grid systems, the model predicted higher peak ozone concentrations with greater detail. Sensitivity calculations were performed to quantify the effect of various inputs on the predicted ozone. Effects of zeroing the initial conditions persisted until 7 July 1988. When using background levels of species concentrations as initial conditions, the effect lasted only for two days of simulation. Boundary conditions impacted the ozone concentrations near the boundary cells only. Emission inputs were the major factor in producing the large concentrations of ozone predicted in the Northeast Corridor. The URM model was also used to study ozone control strategy issues in the Northeast Corridor. A suite of simulations was performed where anthropogenic NO x and VOC emission levels were reducd

  5. An open-access modeled passenger flow matrix for the global air network in 2010.

    PubMed

    Huang, Zhuojie; Wu, Xiao; Garcia, Andres J; Fik, Timothy J; Tatem, Andrew J

    2013-01-01

    The expanding global air network provides rapid and wide-reaching connections accelerating both domestic and international travel. To understand human movement patterns on the network and their socioeconomic, environmental and epidemiological implications, information on passenger flow is required. However, comprehensive data on global passenger flow remain difficult and expensive to obtain, prompting researchers to rely on scheduled flight seat capacity data or simple models of flow. This study describes the construction of an open-access modeled passenger flow matrix for all airports with a host city-population of more than 100,000 and within two transfers of air travel from various publicly available air travel datasets. Data on network characteristics, city population, and local area GDP amongst others are utilized as covariates in a spatial interaction framework to predict the air transportation flows between airports. Training datasets based on information from various transportation organizations in the United States, Canada and the European Union were assembled. A log-linear model controlling the random effects on origin, destination and the airport hierarchy was then built to predict passenger flows on the network, and compared to the results produced using previously published models. Validation analyses showed that the model presented here produced improved predictive power and accuracy compared to previously published models, yielding the highest successful prediction rate at the global scale. Based on this model, passenger flows between 1,491 airports on 644,406 unique routes were estimated in the prediction dataset. The airport node characteristics and estimated passenger flows are freely available as part of the Vector-Borne Disease Airline Importation Risk (VBD-Air) project at: www.vbd-air.com/data.

  6. Summary Report of Air Quality Modeling Research Activities for 2007

    EPA Science Inventory

    Through a Memorandum of Understanding (MOU) and Memorandum of Agreement (MOA) between the U.S. Department of Commerce (DOC) and the U.S. Environmental Protection Agency (EPA), the Atmospheric Sciences Modeling Division (ASMD) of the National Oceanic and Atmospheric Administration...

  7. Construction of Heart Models Using Simple Air Pumps.

    ERIC Educational Resources Information Center

    Lee, Yeung Chung

    2001-01-01

    Recommends the use of heart models in teaching about the circulatory system. Argues that simulation activities can deepen students' understanding of heart structure, dispel misconceptions of the cardiac cycle, and foster awareness of the importance of maintaining a healthy heart. (DDR)

  8. Testing Theoretical Models of Magnetic Damping Using an Air Track

    ERIC Educational Resources Information Center

    Vidaurre, Ana; Riera, Jaime; Monsoriu, Juan A.; Gimenez, Marcos H.

    2008-01-01

    Magnetic braking is a long-established application of Lenz's law. A rigorous analysis of the laws governing this problem involves solving Maxwell's equations in a time-dependent situation. Approximate models have been developed to describe different experimental results related to this phenomenon. In this paper we present a new method for the…

  9. DEVELOPMENT OF AN AGGREGATION AND EPISODE SELECTION SCHEME TO SUPPORT THE MODELS-3 COMMUNITY MULTISCALE AIR QUALITY MODEL

    EPA Science Inventory

    The development of an episode selection and aggregation approach, designed to support distributional estimation of use with the Models-3 Community Multiscale Air Quality (CMAQ) model, is described. The approach utilized cluster analysis of the 700-hPa east-west and north-south...

  10. Air Quality Model Evaluation International Initiative (AQMEII): Advancing State of the Science in Regional Photochemical Modeling and Its Applications

    EPA Science Inventory

    Although the focus in the 1970s was primarily on urban air pollution models, it is well known that pollution problems such as acid rain, ozone, and fine particulate matter are regional in scope, requiring regional-scale multipollutant models. In North America and Europe, several ...

  11. APPLICATION OF THE MODELS-3 COMMUNITY MULTI-SCALE AIR QUALITY (CMAQ) MODEL SYSTEM TO SOS/NASHVILLE 1999

    EPA Science Inventory

    The Models-3 Community Multi-scale Air Quality (CMAQ) model, first released by the USEPA in 1999 (Byun and Ching. 1999), continues to be developed and evaluated. The principal components of the CMAQ system include a comprehensive emission processor known as the Sparse Matrix O...

  12. Modelling of Carbon Monoxide Air Pollution in Larg Cities by Evaluetion of Spectral LANDSAT8 Images

    NASA Astrophysics Data System (ADS)

    Hamzelo, M.; Gharagozlou, A.; Sadeghian, S.; Baikpour, S. H.; Rajabi, A.

    2015-12-01

    Air pollution in large cities is one of the major problems that resolve and reduce it need multiple applications and environmental management. Of The main sources of this pollution is industrial activities, urban and transport that enter large amounts of contaminants into the air and reduces its quality. With Variety of pollutants and high volume manufacturing, local distribution of manufacturing centers, Testing and measuring emissions is difficult. Substances such as carbon monoxide, sulfur dioxide, and unburned hydrocarbons and lead compounds are substances that cause air pollution and carbon monoxide is most important. Today, data exchange systems, processing, analysis and modeling is of important pillars of management system and air quality control. In this study, using the spectral signature of carbon monoxide gas as the most efficient gas pollution LANDSAT8 images in order that have better spatial resolution than appropriate spectral bands and weather meters،SAM classification algorithm and Geographic Information System (GIS ), spatial distribution of carbon monoxide gas in Tehran over a period of one year from the beginning of 2014 until the beginning of 2015 at 11 map have modeled and then to the model valuation ،created maps were compared with the map provided by the Tehran quality comparison air company. Compare involved plans did with the error matrix and results in 4 types of care; overall, producer, user and kappa coefficient was investigated. Results of average accuracy were about than 80%, which indicates the fit method and data used for modeling.

  13. Regression analysis in modeling of air surface temperature and factors affecting its value in Peninsular Malaysia

    NASA Astrophysics Data System (ADS)

    Rajab, Jasim Mohammed; Jafri, Mohd. Zubir Mat; Lim, Hwee San; Abdullah, Khiruddin

    2012-10-01

    This study encompasses air surface temperature (AST) modeling in the lower atmosphere. Data of four atmosphere pollutant gases (CO, O3, CH4, and H2O) dataset, retrieved from the National Aeronautics and Space Administration Atmospheric Infrared Sounder (AIRS), from 2003 to 2008 was employed to develop a model to predict AST value in the Malaysian peninsula using the multiple regression method. For the entire period, the pollutants were highly correlated (R=0.821) with predicted AST. Comparisons among five stations in 2009 showed close agreement between the predicted AST and the observed AST from AIRS, especially in the southwest monsoon (SWM) season, within 1.3 K, and for in situ data, within 1 to 2 K. The validation results of AST with AST from AIRS showed high correlation coefficient (R=0.845 to 0.918), indicating the model's efficiency and accuracy. Statistical analysis in terms of β showed that H2O (0.565 to 1.746) tended to contribute significantly to high AST values during the northeast monsoon season. Generally, these results clearly indicate the advantage of using the satellite AIRS data and a correlation analysis study to investigate the impact of atmospheric greenhouse gases on AST over the Malaysian peninsula. A model was developed that is capable of retrieving the Malaysian peninsulan AST in all weather conditions, with total uncertainties ranging between 1 and 2 K.

  14. Diagnosis of air quality through observation and modeling of volatile organic compounds (VOCs) as pollution tracers

    NASA Astrophysics Data System (ADS)

    Liu, Wen-Tzu; Hsieh, Hsin-Cheng; Chen, Sheng-Po; Chang, Julius S.; Lin, Neng-Huei; Chang, Chih-Chung; Wang, Jia-Lin

    2012-08-01

    This study used selected ambient volatile organic compounds (VOCs) as pollution tracers to study the effects of meteorology on air quality. A remote coastal site was chosen as a receptor to monitor pollutants transported upwind from urban traffic and industrial sources. Large concentration variability in VOC concentrations was observed at the coastal site due to rapid changes in meteorology, which caused periodic land-sea exchange of air masses. To assure the quality of the on-line measurements, uniform concentrations of chlorofluorocarbon-113 (CFC-113) were exploited as an internal check of the instrument's stability and the resulting data quality. A VOC speciated air quality model was employed to simulate both temporal and spatial distributions of VOC plumes. The model successfully captured the general features of the variations of toluene as a pollution tracer, which suggests that emissions and meteorology were reasonably well simulated in the model. Through validation by observation, the model can display both the temporal and spatial distribution of air pollutants in a dynamic manner. Thus, a more insightful understanding of how local air quality is affected by meteorology can be obtained.

  15. Mexico City air quality research initiative, volume 3, modeling and simulation

    SciTech Connect

    Mauzy, A.

    1994-06-01

    The objective of the modeling and simulation task was to develop, test, and apply an appropriate set of models that could translate emission changes into air quality changes. Specifically, we wanted to develop models that could describe how existing measurements of ozone (O{sub 3}), carbon monoxide (CO), and sulfur dioxide (SO{sub 2}) would be expected to change if their emissions were changed. The modeling must be able to address the effects of difference in weather conditions and changes in land use as well as the effects of changes in emission levels. It must also be able to address the effects of changes in the nature and distribution of the emissions as well as changes in the total emissions. A second objective was to provide an understanding of the conditions that lead to poor air quality in Mexico City. We know in a general sense that Mexico City`s poor air quality is the result of large quantities of emissions in a confined area that is subject to light winds, but we did not know much about many aspects of the problem. For example, is the air quality on a given day primarily the result of emissions on that day...or is there an important carryover from previous nights and days? With a good understanding of the important meteorological circumstances that lead to poor air quality, we learn what it take duce an accurate forecast of impending quality so that we can determine the advisability of emergency measures.

  16. A Multiple Agent Model of Human Performance in Automated Air Traffic Control and Flight Management Operations

    NASA Technical Reports Server (NTRS)

    Corker, Kevin; Pisanich, Gregory; Condon, Gregory W. (Technical Monitor)

    1995-01-01

    A predictive model of human operator performance (flight crew and air traffic control (ATC)) has been developed and applied in order to evaluate the impact of automation developments in flight management and air traffic control. The model is used to predict the performance of a two person flight crew and the ATC operators generating and responding to clearances aided by the Center TRACON Automation System (CTAS). The purpose of the modeling is to support evaluation and design of automated aids for flight management and airspace management and to predict required changes in procedure both air and ground in response to advancing automation in both domains. Additional information is contained in the original extended abstract.

  17. Computer model for air-cooled refrigerant condensers with specified refrigerant circuiting

    SciTech Connect

    Ellison, R.D.; Creswick, F.A.; Fischer, S.K.; Jackson, W.L.

    1981-01-01

    A computer model for an air-cooled refrigerant condensor is presented; the model is intended for use in detailed design analyses or in simulation of the performance of existing heat exchangers that have complex refrigerant circuiting or unusual air-side geometries. The model relies on a tube-by-tube computational approach calculating the thermal and fluid-flow performance of each tube in the heat exchanger individually, using local temperatures and heat transfer coefficients. The refrigerant circuiting must be specified; the joining or branching of parallel circuits is accommodated using appropriate mixing expressions. Air-side heat exchange correlations may be specified so that various surface geometries can be investigated. Results of the analyses of two condensers are compared to experiment.

  18. Estimation of whole lemon mass transfer parameters during hot air drying using different modelling methods

    NASA Astrophysics Data System (ADS)

    Torki-Harchegani, Mehdi; Ghanbarian, Davoud; Sadeghi, Morteza

    2015-08-01

    To design new dryers or improve existing drying equipments, accurate values of mass transfer parameters is of great importance. In this study, an experimental and theoretical investigation of drying whole lemons was carried out. The whole lemons were dried in a convective hot air dryer at different air temperatures (50, 60 and 75 °C) and a constant air velocity (1 m s-1). In theoretical consideration, three moisture transfer models including Dincer and Dost model, Bi- G correlation approach and conventional solution of Fick's second law of diffusion were used to determine moisture transfer parameters and predict dimensionless moisture content curves. The predicted results were then compared with the experimental data and the higher degree of prediction accuracy was achieved by the Dincer and Dost model.

  19. Mapping real-time air pollution health risk for environmental management: Combining mobile and stationary air pollution monitoring with neural network models.

    PubMed

    Adams, Matthew D; Kanaroglou, Pavlos S

    2016-03-01

    Air pollution poses health concerns at the global scale. The challenge of managing air pollution is significant because of the many air pollutants, insufficient funds for monitoring and abatement programs, and political and social challenges in defining policy to limit emissions. Some governments provide citizens with air pollution health risk information to allow them to limit their exposure. However, many regions still have insufficient air pollution monitoring networks to provide real-time mapping. Where available, these risk mapping systems either provide absolute concentration data or the concentrations are used to derive an Air Quality Index, which provides the air pollution risk for a mix of air pollutants with a single value. When risk information is presented as a single value for an entire region it does not inform on the spatial variation within the region. Without an understanding of the local variation residents can only make a partially informed decision when choosing daily activities. The single value is typically provided because of a limited number of active monitoring units in the area. In our work, we overcome this issue by leveraging mobile air pollution monitoring techniques, meteorological information and land use information to map real-time air pollution health risks. We propose an approach that can provide improved health risk information to the public by applying neural network models within a framework that is inspired by land use regression. Mobile air pollution monitoring campaigns were conducted across Hamilton from 2005 to 2013. These mobile air pollution data were modelled with a number of predictor variables that included information on the surrounding land use characteristics, the meteorological conditions, air pollution concentrations from fixed location monitors, and traffic information during the time of collection. Fine particulate matter and nitrogen dioxide were both modelled. During the model fitting process we reserved

  20. Mapping real-time air pollution health risk for environmental management: Combining mobile and stationary air pollution monitoring with neural network models.

    PubMed

    Adams, Matthew D; Kanaroglou, Pavlos S

    2016-03-01

    Air pollution poses health concerns at the global scale. The challenge of managing air pollution is significant because of the many air pollutants, insufficient funds for monitoring and abatement programs, and political and social challenges in defining policy to limit emissions. Some governments provide citizens with air pollution health risk information to allow them to limit their exposure. However, many regions still have insufficient air pollution monitoring networks to provide real-time mapping. Where available, these risk mapping systems either provide absolute concentration data or the concentrations are used to derive an Air Quality Index, which provides the air pollution risk for a mix of air pollutants with a single value. When risk information is presented as a single value for an entire region it does not inform on the spatial variation within the region. Without an understanding of the local variation residents can only make a partially informed decision when choosing daily activities. The single value is typically provided because of a limited number of active monitoring units in the area. In our work, we overcome this issue by leveraging mobile air pollution monitoring techniques, meteorological information and land use information to map real-time air pollution health risks. We propose an approach that can provide improved health risk information to the public by applying neural network models within a framework that is inspired by land use regression. Mobile air pollution monitoring campaigns were conducted across Hamilton from 2005 to 2013. These mobile air pollution data were modelled with a number of predictor variables that included information on the surrounding land use characteristics, the meteorological conditions, air pollution concentrations from fixed location monitors, and traffic information during the time of collection. Fine particulate matter and nitrogen dioxide were both modelled. During the model fitting process we reserved

  1. Impact of air traffic emissions on airport air quality. Multi-scale modeling, test bed and field measurements

    NASA Astrophysics Data System (ADS)

    Ramaroson, R.; Vuillot, F.; Durand, Y.; Courbet, B.; Janin, F.; Copalle, A.; Guin, C.; Paux, E.; Vannier, F.; Talbaut, M.; Weill, M.

    2004-12-01

    Air traffic emissions are playing a significant role in airport air quality. Engine emissions contribute to the ozone and PM formation. There is an emergence of a need to develop advanced numerical tools and airport emission databases for air pollution studies. Field monitoring at airports necessary to support model assessment is still limited in time and space. The French ONERA AIRPUR project has focused on three objectives: emission inventories; dispersion models; field measurements. Results are presented and discussed in this paper. The ground spatial distribution of LTO emissions using realistic aircraft trajectories, aircraft-engine classification by ICAO, fuel flow methodology and diurnal variations of fleet number, is presented and discussed. Exhaust species time evolution is simulated using a chemical-dispersion model. Results show high emissions of NOx during LTO, and a maximum of CO and Hydrocarbons during taxi. Depending on seasons, the NOx lifetime is varying differently; lower concentration is calculated far away from LTO emissions. Longer-lived pollutants such as ozone are formed downstream and require the use of advanced dispersion models. For this reason, two interactive models coupling the micro and the regional scales are developed and used in this work. A 3D CFD model (CEDRE) simulates the flow characteristics around buildings and the dispersion of emissions. CEDRE boundary conditions are provided by the 3D nested dispersion model MEDIUM/MM5, which includes a surface boundary layer chemistry and calculates the concentration of pollutants from the local to the airport vicinities. The CFD results show a tracer accumulation calculated downstream beside terminals, consistent with observations at some mega-airports. Sensibility studies are conducted to highlight the impact of emissions on ozone formation with MEDIUM. Results show that longer-lived species are produced downstream, their concentration depending on NOx, aromatics and VOC released by

  2. Monitoring Air Quality over China: Evaluation of the modeling system of the PANDA project

    NASA Astrophysics Data System (ADS)

    Bouarar, Idir; Katinka Petersen, Anna; Brasseur, Guy; Granier, Claire; Xie, Ying; Wang, Xuemei; Fan, Qi; Wang, Lili

    2015-04-01

    Air pollution has become a pressing problem in Asia and specifically in China due to rapid increase in anthropogenic emissions related to growth of China's economic activity and increasing demand for energy in the past decade. Observed levels of particulate matter and ozone regularly exceed World Health Organization (WHO) air quality guidelines in many parts of the country leading to increased risk of respiratory illnesses and other health problems. The EU-funded project PANDA aims to establish a team of European and Chinese scientists to monitor air pollution over China and elaborate air quality indicators in support of European and Chinese policies. PANDA combines state-of-the-art air pollution modeling with space and surface observations of chemical species to improve methods for monitoring air quality. The modeling system of the PANDA project follows a downscaling approach: global models such as MOZART and MACC system provide initial and boundary conditions to regional WRF-Chem and EMEP simulations over East Asia. WRF-Chem simulations at higher resolution (e.g. 20km) are then performed over a smaller domain covering East China and initial and boundary conditions from this run are used to perform simulations at a finer resolution (e.g. 5km) over specific megacities like Shanghai. Here we present results of model simulations for January and July 2010 performed during the first year of the project. We show an intercomparison of the global (MACC, EMEP) and regional (WRF-Chem) simulations and a comprehensive evaluation with satellite measurements (NO2, CO) and in-situ data (O3, CO, NOx, PM10 and PM2.5) at several surface stations. Using the WRF-Chem model, we demonstrate that model performance is influenced not only by the resolution (e.g. 60km, 20km) but also the emission inventories used (MACCity, HTAPv2), their resolution and diurnal variation, and the choice of initial and boundary conditions (e.g. MOZART, MACC analysis).

  3. Decompression Sickness After Air Break in Prebreathe Described with a Survival Model

    NASA Technical Reports Server (NTRS)

    Conkin, J.; Pilmanis, A. A.

    2010-01-01

    Data from Brooks City-Base show the decompression sickness (DCS) and venous gas emboli (VGE) consequences of air breaks in a resting 100% O2 prebreathe (PB) prior to a hypobaric exposure. METHODS: DCS and VGE survival times from 95 controls for a 60 min PB prior to 2-hr or 4-hr exposures to 4.37 psia are statistically compared to 3 break in PB conditions: a 10 min (n=40), 20 min (n=40), or 60 min break (n=32) 30 min into the PB followed by 30 min of PB. Ascent rate was 1,524 meters / min and all exposures included light exercise and 4 min of VGE monitoring of heart chambers at 16 min intervals. DCS survival time for combined control and air breaks were described with an accelerated log logistic model where exponential N2 washin during air break was described with a 10 min half-time and washout during PB with a 60 min half-time. RESULTS: There was no difference in VGE or DCS survival times among 3 different air breaks, or when air breaks were compared to control VGE times. However, 10, 20, and 60 min air breaks had significantly earlier survival times compared to control DCS times, certainly early in the exposures. CONCLUSION: Air breaks of 10, 20, and 60 min after 30 min of a 60 min PB reduced DCS survival time. The survival model combined discrete comparisons into a global description mechanistically linked to asymmetrical N2 washin and washout kinetics based on inspired pN2. Our unvalidated regression is used to compute additional PB time needed to compensate for an air break in PB within the range of tested conditions.

  4. CMAQ (Community Multi-Scale Air Quality) atmospheric distribution model adaptation to region of Hungary

    NASA Astrophysics Data System (ADS)

    Lázár, Dóra; Weidinger, Tamás

    2016-04-01

    For our days, it has become important to measure and predict the concentration of harmful atmospheric pollutants such as dust, aerosol particles of different size ranges, nitrogen compounds, and ozone. The Department of Meteorology at Eötvös Loránd University has been applying the WRF (Weather Research and Forecasting) model several years ago, which is suitable for weather forecasting tasks and provides input data for various environmental models (e.g. DNDC). By adapting the CMAQ (Community Multi-scale Air Quality) model we have designed a combined ambient air-meteorological model (WRF-CMAQ). In this research it is important to apply different emission databases and a background model describing the initial distribution of the pollutant. We used SMOKE (Sparse Matrix Operator Kernel Emissions) model for construction emission dataset from EMEP (European Monitoring and Evaluation Programme) inventories and GEOS-Chem model for initial and boundary conditions. Our model settings were CMAQ CB05 (Carbon Bond 2005) chemical mechanism with 108 x 108 km, 36 x 36 km and 12 x 12 km grids for regions of Europe, the Carpathian Basin and Hungary respectively. i) The structure of the model system, ii) a case study for Carpathian Basin (an anticyclonic weather situation at 21th September 2012) are presented. iii) Verification of ozone forecast has been provided based on the measurements of background air pollution stations. iv) Effects of model attributes (f.e. transition time, emission dataset, parameterizations) for the ozone forecast in Hungary are also investigated.

  5. Modeling CO2 air dispersion from gas driven lake eruptions

    NASA Astrophysics Data System (ADS)

    Chiodini, Giovanni; Costa, Antonio; Rouwet, Dmitri; Tassi, Franco

    2016-04-01

    The most tragic event of gas driven lake eruption occurred at Lake Nyos (Cameroon) on 21 August 1986, when a dense cloud of CO2 suffocated more than 1700 people and an uncounted number of animals in just one night. The event stimulated a series of researches aimed to understand gas origins, gas release mechanisms and strategies for gas hazard mitigation. Very few studies have been carried out for describing the transport of dense CO2 clouds in the atmosphere. Although from a theoretical point of view, gas dispersion can be fully studied by solving the complete equations system for mass, momentum and energy transport, in actual practice, different simplified models able to describe only specific phases or aspects have to be used. In order to simulate dispersion of a heavy gas and to assess the consequent hazard we used a model based on a shallow layer approach (TWODEE2). This technique which uses depth-averaged variables to describe the flow behavior of dense gas over complex topography represents a good compromise between the complexity of computational fluid dynamic models and the simpler integral models. Recently the model has been applied for simulating CO2 dispersion from natural gas emissions in Central Italy. The results have shown how the dispersion pattern is strongly affected by the intensity of gas release, the topography and the ambient wind speed. Here for the first time we applied TWODEE2 code to simulate the dispersion of the large CO2 clouds released by limnic eruptions. An application concerns the case of the 1986 event at lake Nyos. Some difficulties for the simulations were related to the lack of quantitative information: gas flux estimations are not well constrained, meteorological conditions are only qualitatively known, the digital model of the terrain is of poor quality. Different scenarios were taken into account in order to reproduce the qualitative observations available for such episode. The observations regard mainly the effects of gas on

  6. Advances in Linked Air Quality, Farm Management and Biogeochemistry Models to Address Bidirectional Ammonia Flux in CMAQ

    EPA Science Inventory

    Recent increases in anthropogenic inputs of nitrogen to air, land and water media pose a growing threat to human health and ecosystems. Modeling of air-surface N flux is one area in need of improvement. Implementation of a linked air quality and cropland management system is de...

  7. "Advances in Linked Air Quality, Farm Management and Biogeochemistry Models to Address Bidrectional Ammonia Flux in CMAQ"

    EPA Science Inventory

    Recent increases in anthropogenic inputs of nitrogen to air, land and water media pose a growing threat to human health and ecosystems. Modeling of air-surface N flux is one area in need of improvement. Implementation of a linked air quality and cropland management system is de...

  8. Model-Based Design of Air Traffic Controller-Automation Interaction

    NASA Technical Reports Server (NTRS)

    Romahn, Stephan; Callantine, Todd J.; Palmer, Everett A.; Null, Cynthia H. (Technical Monitor)

    1998-01-01

    A model of controller and automation activities was used to design the controller-automation interactions necessary to implement a new terminal area air traffic management concept. The model was then used to design a controller interface that provides the requisite information and functionality. Using data from a preliminary study, the Crew Activity Tracking System (CATS) was used to help validate the model as a computational tool for describing controller performance.

  9. Model Update of a Micro Air Vehicle (MAV) Flexible Wing Frame with Uncertainty Quantification

    NASA Technical Reports Server (NTRS)

    Reaves, Mercedes C.; Horta, Lucas G.; Waszak, Martin R.; Morgan, Benjamin G.

    2004-01-01

    This paper describes a procedure to update parameters in the finite element model of a Micro Air Vehicle (MAV) to improve displacement predictions under aerodynamics loads. Because of fabrication, materials, and geometric uncertainties, a statistical approach combined with Multidisciplinary Design Optimization (MDO) is used to modify key model parameters. Static test data collected using photogrammetry are used to correlate with model predictions. Results show significant improvements in model predictions after parameters are updated; however, computed probabilities values indicate low confidence in updated values and/or model structure errors. Lessons learned in the areas of wing design, test procedures, modeling approaches with geometric nonlinearities, and uncertainties quantification are all documented.

  10. Towards a forecasting system of air quality for Asia using the WRF-Chem model

    NASA Astrophysics Data System (ADS)

    Katinka Petersen, Anna; Kumar, Rajesh; Brasseur, Guy; Granier, Claire

    2013-04-01

    The degradation of air quality in Asia resulting from the intensification of human activities, and the related impacts on the health of billions of people have become an urgent matter of concern. The World Health Organization states that each year nearly 3.3 million people die worldwide prematurely because of air pollution. The situation is particularly acute in Asia. Improving air quality over the Asian continent has become a major challenge for national, regional and local authorities. A prerequisite for air quality improvement is the development of a reliable monitoring system with surface instrumentation and space platforms as well as an analysis and prediction system based on an advanced chemical-meteorological model. The aim is to use the WRF-Chem model for the prediction of daily air quality for the Asian continent with spatial resolution that will be increased in densely populated areas by grid nesting. The modeling system covers a nearly the entire Asian continent so that transport processes of chemical compounds within the continent are simulated and analyzed. To additionally account for the long-range effects and assess their relative importance against regional emissions, the regional chemical transport modeling system uses information from a global modeling system as boundary conditions. The first steps towards a forecasting system over Asia are to test the model performance over this large model domain and the different emissions inventories available for Asia. In this study, the WRF-Chem model was run for a domain covering 60°E to 150°E, 5°S to 50°N at a resolution of 60 km x 60 km for January 2006 with three alternative emission inventories available for Asia (MACCITY, INTEX-B and REAS). We present an intercomparison of the three different simulations and evaluate the simulations with satellite and in situ observations, with focus on ozone, particulate matter, nitrogen oxides and carbon monoxide. The differences between the simulations using

  11. Artificial intelligence modeling to evaluate field performance of photocatalytic asphalt pavement for ambient air purification.

    PubMed

    Asadi, Somayeh; Hassan, Marwa; Nadiri, Ataallah; Dylla, Heather

    2014-01-01

    In recent years, the application of titanium dioxide (TiO₂) as a photocatalyst in asphalt pavement has received considerable attention for purifying ambient air from traffic-emitted pollutants via photocatalytic processes. In order to control the increasing deterioration of ambient air quality, urgent and proper risk assessment tools are deemed necessary. However, in practice, monitoring all process parameters for various operating conditions is difficult due to the complex and non-linear nature of air pollution-based problems. Therefore, the development of models to predict air pollutant concentrations is very useful because it can provide early warnings to the population and also reduce the number of measuring sites. This study used artificial neural network (ANN) and neuro-fuzzy (NF) models to predict NOx concentration in the air as a function of traffic count (Tr) and climatic conditions including humidity (H), temperature (T), solar radiation (S), and wind speed (W) before and after the application of TiO₂ on the pavement surface. These models are useful for modeling because of their ability to be trained using historical data and because of their capability for modeling highly non-linear relationships. To build these models, data were collected from a field study where an aqueous nano TiO₂ solution was sprayed on a 0.2-mile of asphalt pavement in Baton Rouge, LA. Results of this study showed that the NF model provided a better fitting to NOx measurements than the ANN model in the training, validation, and test steps. Results of a parametric study indicated that traffic level, relative humidity, and solar radiation had the most influence on photocatalytic efficiency.

  12. Semi-analytical modelling of positive corona discharge in air

    NASA Astrophysics Data System (ADS)

    Pontiga, Francisco; Yanallah, Khelifa; Chen, Junhong

    2013-09-01

    Semianalytical approximate solutions of the spatial distribution of electric field and electron and ion densities have been obtained by solving Poisson's equations and the continuity equations for the charged species along the Laplacian field lines. The need to iterate for the correct value of space charge on the corona electrode has been eliminated by using the corona current distribution over the grounded plane derived by Deutsch, which predicts a cos m θ law similar to Warburg's law. Based on the results of the approximated model, a parametric study of the influence of gas pressure, the corona wire radius, and the inter-electrode wire-plate separation has been carried out. Also, the approximate solutions of the electron number density has been combined with a simplified plasma chemistry model in order to compute the ozone density generated by the corona discharge in the presence of a gas flow. This work was supported by the Consejeria de Innovacion, Ciencia y Empresa (Junta de Andalucia) and by the Ministerio de Ciencia e Innovacion, Spain, within the European Regional Development Fund contracts FQM-4983 and FIS2011-25161.

  13. Use of Air Modeling to Reduce Facility Demolition Costs

    SciTech Connect

    Smith, Dennis; Sanford, Peter; Parsons, Duane A.

    2003-02-26

    DOE faces the problem of decommissioning facilities contaminated with plutonium, uranium, and beryllium. The standard process has been to remove the contaminated process equipment from a facility, and then decontaminate the residual radiological and hazardous contamination from the facility structure to an ''unconditional release'' level. The facility would then be taken down as a clean demolition. Several beryllium-contaminated facilities were identified that will be particularly difficult to decontaminate to these release levels. A number of alternative decommissioning approaches were investigated that would require less decontamination, and thus reduced cost and schedule. Initial alternative approaches proposed erection of barriers (i.e. building-size tent structures with ventilation controls) to minimize the release of contamination to the environment. More recently we have investigated methods to control contamination at the structure surfaces before and during demolition, and model the risk posed to the workers, public, and the environment by the small residual material actually dispersed. This approach promises to minimize decontamination by removing only the highest contamination levels, and eliminates the need for erecting large contamination control structures along with the attendant ventilation equipment and administrative controls. The modeling has demonstrated the regulatory acceptability of this approach, and the approach is ready to be discussed with the regulators and the public.

  14. A new guide for commissioning air handling systems: Using a model functional test

    SciTech Connect

    Haasl, Tudi; Sellers, David; Friedman, Hannah; Piette, Mary Ann; Bourassa, Norman; Gillespie, Ken

    2002-05-01

    Functional tests are a set of detailed instructions for building commissioning that demand extensive HVAC system knowledge to write and perform. Understanding the energy use implications and theory behind the test procedures, estimating the costs and benefits of doing a particular test, implementing the tests correctly, and resolving problems require years of field experience. As part of a large research project now underway, a practical guide is being developed that communicates this knowledge. This paper presents the components and intended use of the Functional Testing Guide and Model Functional Test for Air Handling Systems. A series of model functional tests, starting at the outdoor air intake section and proceeding through the air handling unit, distribution system, and terminal equipment and ending at the exhaust air discharge point, are provided for many commonly installed air handling system configurations. The model functional tests contain advice for tailoring the test procedures to specific system configurations, desirable and undesirable testing outcomes, a calculation appendix, references to other resources, and examples of completed test forms. The guide is an educational resource, with background information that clarifies the principles behind testing configurations and results. The functional tests have been selected from an extensive commissioning test protocol library compiled by Pacific Gas and Electric in 2001. The guide also includes a design guideline for the selection of control and monitoring points and a design intent documentation form.

  15. Interim Project Results: United Parcel Service's Second-Generation Hybrid-Electric Delivery Vans (Fact Sheet)

    SciTech Connect

    Not Available

    2012-01-01

    This fact sheet describes the performance evaluation of United Parcel Service's second-generation hybrid-electric delivery vans. The Fleet Test and Evaluation Team at the National Renewable Energy Laboratory (NREL) is evaluating the 18-month, in-service performance of 11 of these vans along with 11 comparable conventional diesel vans operating in Minneapolis, Minnesota. As a complement to the field study, the team recently completed fuel economy and emissions testing at NREL's Renewable Fuels and Lubricants (ReFUEL) laboratory.

  16. Rodent models of cardiopulmonary disease: their potential applicability in studies of air pollutant susceptibility.

    PubMed Central

    Kodavanti, U P; Costa, D L; Bromberg, P A

    1998-01-01

    The mechanisms by which increased mortality and morbidity occur in individuals with preexistent cardiopulmonary disease following acute episodes of air pollution are unknown. Studies involving air pollution effects on animal models of human cardiopulmonary diseases are both infrequent and difficult to interpret. Such models are, however, extensively used in studies of disease pathogenesis. Primarily they comprise those developed by genetic, pharmacologic, or surgical manipulations of the cardiopulmonary system. This review attempts a comprehensive description of rodent cardiopulmonary disease models in the context of their potential application to susceptibility studies of air pollutants regardless of whether the models have been previously used for such studies. The pulmonary disease models include bronchitis, emphysema, asthma/allergy, chronic obstructive pulmonary disease, interstitial fibrosis, and infection. The models of systemic hypertension and congestive heart failure include: those derived by genetics (spontaneously hypertensive, Dahl S. renin transgenic, and other rodent models); congestive heart failure models derived by surgical manipulations; viral myocarditis; and cardiomyopathy induced by adriamycin. The characteristic pathogenic features critical to understanding the susceptibility to inhaled toxicants are described. It is anticipated that this review will provide a ready reference for the selection of appropriate rodent models of cardiopulmonary diseases and identify not only their pathobiologic similarities and/or differences to humans but also their potential usefulness in susceptibility studies. Images Figure 2 PMID:9539009

  17. Model analysis and nonlinear control of air compressors

    NASA Astrophysics Data System (ADS)

    Sari, Gholam-Reza

    For decades, gas turbines have been important, widespread, and reliable devices in the field of power generation, petrochemical industry, and aeronautics. They employ centrifugal and axial compressors which suffer from aerodynamic instabilities, namely, surge and rotating stall. These performance limiting instabilities can cause component stress, lifespan reduction, noise, and vibration. Furthermore, in variable speed axial compressors (VSACs), speed variations affect the system stability and can lead to surge and rotating stall. This limits the rate of speed variations and results in important performance penalties. The present work firstly addresses the bifurcation analysis of VSACs' model to investigate the impact of speed dynamics on the stability of efficient operating points. Here, the rate of speed variations (acceleration rate) is defined as a new parameter of the model and a detailed numerical bifurcation analysis is provided. The results of time-domain simulations not only validate the results of bifurcation analysis, but also broaden our knowledge about the transient response of the model, which is a matter of importance as well. The analysis reveals that speed variations can lead to a fully developed rotating stall as well as the previously reported temporary stall developments. The results show that the developed instabilities depend to a great extent on the acceleration rate. The impact of other key issues such as throttle gain, viscosity factor, initial speed, final speed, and the contribution of stall modes are also explored. From the control point of view, despite reported achievements, robust control design for compression systems remains a challenging problem. In this work, at first, two nonlinear approaches are proposed to tackle the stability problem of constant-speed axial compressors (CSACs). The first approach is a robust passivity-based control and the second one is a second order sliding mode control. The approaches tackle the challenging

  18. Computational neuroanatomy using brain deformations: From brain parcellation to multivariate pattern analysis and machine learning.

    PubMed

    Davatzikos, Christos

    2016-10-01

    The past 20 years have seen a mushrooming growth of the field of computational neuroanatomy. Much of this work has been enabled by the development and refinement of powerful, high-dimensional image warping methods, which have enabled detailed brain parcellation, voxel-based morphometric analyses, and multivariate pattern analyses using machine learning approaches. The evolution of these 3 types of analyses over the years has overcome many challenges. We present the evolution of our work in these 3 directions, which largely follows the evolution of this field. We discuss the progression from single-atlas, single-registration brain parcellation work to current ensemble-based parcellation; from relatively basic mass-univariate t-tests to optimized regional pattern analyses combining deformations and residuals; and from basic application of support vector machines to generative-discriminative formulations of multivariate pattern analyses, and to methods dealing with heterogeneity of neuroanatomical patterns. We conclude with discussion of some of the future directions and challenges. PMID:27514582

  19. Computational neuroanatomy using brain deformations: From brain parcellation to multivariate pattern analysis and machine learning.

    PubMed

    Davatzikos, Christos

    2016-10-01

    The past 20 years have seen a mushrooming growth of the field of computational neuroanatomy. Much of this work ha