Science.gov

Sample records for farm simulation presentation

  1. Adding Complex Terrain and Stable Atmospheric Condition Capability to the Simulator for On/Offshore Wind Farm Applications (SOWFA) (Presentation)

    SciTech Connect

    Churchfield, M. J.

    2013-06-01

    This presentation describes changes made to NREL's OpenFOAM-based wind plant aerodynamics solver so that it can compute the stably stratified atmospheric boundary layer and flow over terrain. Background about the flow solver, the Simulator for Off/Onshore Wind Farm Applications (SOWFA) is given, followed by details of the stable stratification/complex terrain modifications to SOWFA, along with some preliminary results calculations of a stable atmospheric boundary layer and flow over a simple set of hills.

  2. A CFD framework for offshore and onshore wind farm simulation

    NASA Astrophysics Data System (ADS)

    Avila, Matias; Gargallo-Peiró, Abel; Folch, Arnau

    2017-05-01

    We present a wind simulation framework for offshore and onshore wind farms. The simulation framework involves an automatic hybrid high-quality mesh generation process, a pre-processing to impose initial and boundary conditions, and a solver for the Reynolds Averaged Navier-Stokes (RANS) equations with two different turbulence models, a modified standard k-ɛ model and a realizable k-ɛ model in which we included the Coriolis effects. Wind turbines are modeled as actuator discs. The wind farm simulation framework has been implemented in Alya, an in-house High Performance Computing (HPC) multi-physics finite element parallel solver. An application example is shown for an onshore wind farm composed of 165 turbines.

  3. A survey of modelling methods for high-fidelity wind farm simulations using large eddy simulation.

    PubMed

    Breton, S-P; Sumner, J; Sørensen, J N; Hansen, K S; Sarmast, S; Ivanell, S

    2017-04-13

    Large eddy simulations (LES) of wind farms have the capability to provide valuable and detailed information about the dynamics of wind turbine wakes. For this reason, their use within the wind energy research community is on the rise, spurring the development of new models and methods. This review surveys the most common schemes available to model the rotor, atmospheric conditions and terrain effects within current state-of-the-art LES codes, of which an overview is provided. A summary of the experimental research data available for validation of LES codes within the context of single and multiple wake situations is also supplied. Some typical results for wind turbine and wind farm flows are presented to illustrate best practices for carrying out high-fidelity LES of wind farms under various atmospheric and terrain conditions.This article is part of the themed issue 'Wind energy in complex terrains'.

  4. Statistics of LES Simulations of Large Wind Farms

    NASA Astrophysics Data System (ADS)

    Juhl Andersen, Søren; Nørkær Sørensen, Jens; Mikkelsen, Robert; Ivanell, Stefan

    2016-09-01

    Numerous large eddy simulations are performed of large wind farms using the actuator line method, which has been fully coupled to the aero-elastic code, Flex5. The higher order moments of the flow field inside large wind farms is examined in order to determine a representative reference velocity. The statistical moments appear to collapse and hence the turbulence inside large wind farms can potentially be scaled accordingly. The thrust coefficient is estimated by two different reference velocities and the generic CT expression by Frandsen. A reference velocity derived from the power production is shown to give very good agreement and furthermore enables the very good estimation of the thrust force using only the steady CT -curve, even for very short time samples. Finally, the effective turbulence inside large wind farms and the equivalent loads are examined.

  5. Simulation and optimal control of wind-farm boundary layers

    NASA Astrophysics Data System (ADS)

    Meyers, Johan; Goit, Jay

    2014-05-01

    In large wind farms, the effect of turbine wakes, and their interaction leads to a reduction in farm efficiency, with power generated by turbines in a farm being lower than that of a lone-standing turbine by up to 50%. In very large wind farms or `deep arrays', this efficiency loss is related to interaction of the wind farms with the planetary boundary layer, leading to lower wind speeds at turbine level. Moreover, for these cases it has been demonstrated both in simulations and wind-tunnel experiments that the wind-farm energy extraction is dominated by the vertical turbulent transport of kinetic energy from higher regions in the boundary layer towards the turbine level. In the current study, we investigate the use of optimal control techniques combined with Large-Eddy Simulations (LES) of wind-farm boundary layer interaction for the increase of total energy extraction in very large `infinite' wind farms. We consider the individual wind turbines as flow actuators, whose energy extraction can be dynamically regulated in time so as to optimally influence the turbulent flow field, maximizing the wind farm power. For the simulation of wind-farm boundary layers we use large-eddy simulations in combination with actuator-disk and actuator-line representations of wind turbines. Simulations are performed in our in-house pseudo-spectral code SP-Wind that combines Fourier-spectral discretization in horizontal directions with a fourth-order finite-volume approach in the vertical direction. For the optimal control study, we consider the dynamic control of turbine-thrust coefficients in an actuator-disk model. They represent the effect of turbine blades that can actively pitch in time, changing the lift- and drag coefficients of the turbine blades. Optimal model-predictive control (or optimal receding horizon control) is used, where the model simply consists of the full LES equations, and the time horizon is approximately 280 seconds. The optimization is performed using a

  6. Simulation of a 7.7 MW onshore wind farm with the Actuator Line Model

    NASA Astrophysics Data System (ADS)

    Guggeri, A.; Draper, M.; Usera, G.

    2017-05-01

    Recently, the Actuator Line Model (ALM) has been evaluated with coarser resolution and larger time steps than what is generally recommended, taking into account an atmospheric sheared and turbulent inflow condition. The aim of the present paper is to continue these studies, assessing the capability of the ALM to represent the wind turbines’ interactions in an onshore wind farm. The ‘Libertad’ wind farm, which consists of four 1.9MW Vestas V100 wind turbines, was simulated considering different wind directions, and the results were compared with the wind farm SCADA data, finding good agreement between them. A sensitivity analysis was performed to evaluate the influence of the spatial resolution, finding acceptable agreement, although some differences were found. It is believed that these differences are due to the characteristics of the different Atmospheric Boundary Layer (ABL) simulations taken as inflow condition (precursor simulations).

  7. Simulations of an Offshore Wind Farm Using Large-Eddy Simulation and a Torque-Controlled Actuator Disc Model

    NASA Astrophysics Data System (ADS)

    Creech, Angus; Früh, Wolf-Gerrit; Maguire, A. Eoghan

    2015-05-01

    We present here a computational fluid dynamics (CFD) simulation of Lillgrund offshore wind farm, which is located in the Øresund Strait between Sweden and Denmark. The simulation combines a dynamic representation of wind turbines embedded within a large-eddy simulation CFD solver and uses hr-adaptive meshing to increase or decrease mesh resolution where required. This allows the resolution of both large-scale flow structures around the wind farm, and the local flow conditions at individual turbines; consequently, the response of each turbine to local conditions can be modelled, as well as the resulting evolution of the turbine wakes. This paper provides a detailed description of the turbine model which simulates the interaction between the wind, the turbine rotors, and the turbine generators by calculating the forces on the rotor, the body forces on the air, and instantaneous power output. This model was used to investigate a selection of key wind speeds and directions, investigating cases where a row of turbines would be fully aligned with the wind or at specific angles to the wind. Results shown here include presentations of the spin-up of turbines, the observation of eddies moving through the turbine array, meandering turbine wakes, and an extensive wind farm wake several kilometres in length. The key measurement available for cross-validation with operational wind farm data is the power output from the individual turbines, where the effect of unsteady turbine wakes on the performance of downstream turbines was a main point of interest. The results from the simulations were compared to the performance measurements from the real wind farm to provide a firm quantitative validation of this methodology. Having achieved good agreement between the model results and actual wind farm measurements, the potential of the methodology to provide a tool for further investigations of engineering and atmospheric science problems is outlined.

  8. Simulation of an offshore wind farm using fluid power for centralized electricity generation

    NASA Astrophysics Data System (ADS)

    Jarquin-Laguna, A.

    2016-09-01

    A centralized approach for electricity generation within a wind farm is explored through the use of fluid power technology. This concept considers a new way of generation, collection and transmission of wind energy inside a wind farm, in which electrical conversion does not occur during any intermediate conversion step before the energy has reached the offshore central platform. A numerical model was developed to capture the relevant physics from the dynamic interaction between different turbines coupled to a common hydraulic network and controller. This paper presents two examples of the time-domain simulation results for an hypothetical hydraulic wind farm subject to turbulent wind conditions. The performance and operational parameters of individual turbines are compared with those of a reference wind farm with conventional technology turbines, using the same wind farm layout and environmental conditions. For the presented case study, results indicate that the individual wind turbines are able to operate within operational limits with the current pressure control concept. Despite the stochastic turbulent wind input and wake effects, the hydraulic wind farm is able to produce electricity with reasonable performance in both below and above rated conditions.

  9. Simulation and analysis of conjunctive use with MODFLOW's farm process.

    PubMed

    Hanson, R T; Schmid, W; Faunt, C C; Lockwood, B

    2010-01-01

    The extension of MODFLOW onto the landscape with the Farm Process (MF-FMP) facilitates fully coupled simulation of the use and movement of water from precipitation, streamflow and runoff, groundwater flow, and consumption by natural and agricultural vegetation throughout the hydrologic system at all times. This allows for more complete analysis of conjunctive use water-resource systems than previously possible with MODFLOW by combining relevant aspects of the landscape with the groundwater and surface water components. This analysis is accomplished using distributed cell-by-cell supply-constrained and demand-driven components across the landscape within "water-balance subregions" comprised of one or more model cells that can represent a single farm, a group of farms, or other hydrologic or geopolitical entities. Simulation of micro-agriculture in the Pajaro Valley and macro-agriculture in the Central Valley are used to demonstrate the utility of MF-FMP. For Pajaro Valley, the simulation of an aquifer storage and recovery system and related coastal water distribution system to supplant coastal pumpage was analyzed subject to climate variations and additional supplemental sources such as local runoff. For the Central Valley, analysis of conjunctive use from different hydrologic settings of northern and southern subregions shows how and when precipitation, surface water, and groundwater are important to conjunctive use. The examples show that through MF-FMP's ability to simulate natural and anthropogenic components of the hydrologic cycle, the distribution and dynamics of supply and demand can be analyzed, understood, and managed. This analysis of conjunctive use would be difficult without embedding them in the simulation and are difficult to estimate a priori.

  10. Simulation and analysis of conjunctive use with MODFLOW's farm process

    USGS Publications Warehouse

    Hanson, R.T.; Schmid, W.; Faunt, C.C.; Lockwood, B.

    2010-01-01

    The extension of MODFLOW onto the landscape with the Farm Process (MF-FMP) facilitates fully coupled simulation of the use and movement of water from precipitation, streamflow and runoff, groundwater flow, and consumption by natural and agricultural vegetation throughout the hydrologic system at all times. This allows for more complete analysis of conjunctive use water-resource systems than previously possible with MODFLOW by combining relevant aspects of the landscape with the groundwater and surface water components. This analysis is accomplished using distributed cell-by-cell supply-constrained and demand-driven components across the landscape within " water-balance subregions" comprised of one or more model cells that can represent a single farm, a group of farms, or other hydrologic or geopolitical entities. Simulation of micro-agriculture in the Pajaro Valley and macro-agriculture in the Central Valley are used to demonstrate the utility of MF-FMP. For Pajaro Valley, the simulation of an aquifer storage and recovery system and related coastal water distribution system to supplant coastal pumpage was analyzed subject to climate variations and additional supplemental sources such as local runoff. For the Central Valley, analysis of conjunctive use from different hydrologic settings of northern and southern subregions shows how and when precipitation, surface water, and groundwater are important to conjunctive use. The examples show that through MF-FMP's ability to simulate natural and anthropogenic components of the hydrologic cycle, the distribution and dynamics of supply and demand can be analyzed, understood, and managed. This analysis of conjunctive use would be difficult without embedding them in the simulation and are difficult to estimate a priori. Journal compilation ?? 2010 National Ground Water Association. No claim to original US government works.

  11. Linearized simulation of flow over wind farms and complex terrains.

    PubMed

    Segalini, Antonio

    2017-04-13

    The flow over complex terrains and wind farms is estimated here by numerically solving the linearized Navier-Stokes equations. The equations are linearized around the unperturbed incoming wind profile, here assumed logarithmic. The Boussinesq approximation is used to model the Reynolds stress with a prescribed turbulent eddy viscosity profile. Without requiring the boundary-layer approximation, two new linear equations are obtained for the vertical velocity and the wall-normal vorticity, with a reduction in the computational cost by a factor of 8 when compared with a primitive-variables formulation. The presence of terrain elevation is introduced as a vertical coordinate shift, while forestry or wind turbines are included as body forces, without any assumption about the wake structure for the turbines. The model is first validated against some available experiments and simulations, and then a simulation of a wind farm over a Gaussian hill is performed. The speed-up effect of the hill is clearly beneficial in terms of the available momentum upstream of the crest, while downstream of it the opposite can be said as the turbines face a decreased wind speed. Also, the presence of the hill introduces an additional spanwise velocity component that may also affect the turbines' operations. The linear superposition of the flow over the hill and the flow over the farm alone provided a first estimation of the wind speed along the farm, with discrepancies of the same order of magnitude for the spanwise velocity. Finally, the possibility of using a parabolic set of equations to obtain the turbulent kinetic energy after the linearized model is investigated with promising results.This article is part of the themed issue 'Wind energy in complex terrains'.

  12. Linearized simulation of flow over wind farms and complex terrains

    NASA Astrophysics Data System (ADS)

    Segalini, Antonio

    2017-03-01

    The flow over complex terrains and wind farms is estimated here by numerically solving the linearized Navier-Stokes equations. The equations are linearized around the unperturbed incoming wind profile, here assumed logarithmic. The Boussinesq approximation is used to model the Reynolds stress with a prescribed turbulent eddy viscosity profile. Without requiring the boundary-layer approximation, two new linear equations are obtained for the vertical velocity and the wall-normal vorticity, with a reduction in the computational cost by a factor of 8 when compared with a primitive-variables formulation. The presence of terrain elevation is introduced as a vertical coordinate shift, while forestry or wind turbines are included as body forces, without any assumption about the wake structure for the turbines. The model is first validated against some available experiments and simulations, and then a simulation of a wind farm over a Gaussian hill is performed. The speed-up effect of the hill is clearly beneficial in terms of the available momentum upstream of the crest, while downstream of it the opposite can be said as the turbines face a decreased wind speed. Also, the presence of the hill introduces an additional spanwise velocity component that may also affect the turbines' operations. The linear superposition of the flow over the hill and the flow over the farm alone provided a first estimation of the wind speed along the farm, with discrepancies of the same order of magnitude for the spanwise velocity. Finally, the possibility of using a parabolic set of equations to obtain the turbulent kinetic energy after the linearized model is investigated with promising results. This article is part of the themed issue 'Wind energy in complex terrains'.

  13. Modeling and simulation of offshore wind farm O&M processes

    SciTech Connect

    Joschko, Philip; Widok, Andi H.; Appel, Susanne; Greiner, Saskia; Albers, Henning; Page, Bernd

    2015-04-15

    This paper describes a holistic approach to operation and maintenance (O&M) processes in the domain of offshore wind farm power generation. The acquisition and process visualization is followed by a risk analysis of all relevant processes. Hereafter, a tool was designed, which is able to model the defined processes in a BPMN 2.0 notation, as well as connect and simulate them. Furthermore, the notation was enriched with new elements, representing other relevant factors that were, to date, only displayable with much higher effort. In that regard a variety of more complex situations were integrated, such as for example new process interactions depending on different weather influences, in which case a stochastic weather generator was combined with the business simulation or other wind farm aspects important to the smooth running of the offshore wind farms. In addition, the choices for different methodologies, such as the simulation framework or the business process notation will be presented and elaborated depending on the impact they had on the development of the approach and the software solution. - Highlights: • Analysis of operation and maintenance processes of offshore wind farms • Process modeling with BPMN 2.0 • Domain-specific simulation tool.

  14. Simulation of wake effects between two wind farms

    NASA Astrophysics Data System (ADS)

    Hansen, K. S.; Réthoré, P.-E.; Palma, J.; Hevia, B. G.; Prospathopoulos, J.; Peña, A.; Ott, S.; Schepers, G.; Palomares, A.; van der Laan, M. P.; Volker, P.

    2015-06-01

    SCADA data, recorded on the downstream wind farm, has been used to identify flow cases with visible clustering effects. The inflow condition is derived from a partly undisturbed wind turbine, due to lack of mast measurements. The SCADA data analysis concludes that centre of the deficit for the downstream wind farm with disturbed inflow has a distinct visible maximum deficit zone located only 5-10D downstream from the entrance. This zone, representing 20-30% speed reduction, increases and moves downstream for increasing cluster effect and is not visible outside a flow sector of 20-30°. The eight flow models represented in this benchmark include both RANS models, mesoscale models and engineering models. The flow cases, identified according to the wind speed level and inflow sector, have been simulated and validated with the SCADA results. The model validation concludes that all models more or less are able to predict the location and size of the deficit zone inside the downwind wind farm.

  15. Impact simulation of shrimp farm effluent on BOD-DO in Setiu River

    NASA Astrophysics Data System (ADS)

    Chong, Michael Sueng Lock; Teh, Su Yean; Koh, Hock Lye

    2017-08-01

    Release of effluent from intensive aquaculture farms into a river can pollute the receiving river and exert negative impacts on the aquatic ecosystem. In this paper, we simulate the effects of effluent released from a marine shrimp aquaculture farm into Sg Setiu, focusing on two critical water quality parameters i.e. DO (dissolved oxygen) and BOD (biochemical oxygen demand). DO is an important constituent in a river in sustaining water quality, with levels of DO below 5 mg/L deemed undesirable. DO levels can be depressed by the presence of BOD and other organics that consume DO. Water quality simulations in conjunction with management of effluent treatment can suggest mitigation measures for reducing the adverse environmental impact. For this purpose, an in-house two-dimensional water quality simulation model codenamed TUNA-WQ will be used for these simulations. TUNA-WQ has been undergoing regular updates and improvements to broaden the applicability and to improve the robustness. Here, the model is calibrated and verified for simulation of DO and BOD dynamics in Setiu River (Sg Setiu). TUNA-WQ simulated DO and BOD in Setiu River due to the discharge from a marine shrimp aquaculture farm will be presented.

  16. Simulating forage crop production in a northern climate with the Integrated Farm System Model

    USDA-ARS?s Scientific Manuscript database

    Whole-farm simulation models are useful tools for evaluating the effect of management practices and climate variability on the agro-environmental and economic performance of farms. A few process-based farm-scale models have been developed, but none have been evaluated in a northern region with a sho...

  17. Wind-farm simulation over moderately complex terrain

    NASA Astrophysics Data System (ADS)

    Segalini, Antonio; Castellani, Francesco

    2017-05-01

    A comparison between three independent software to estimate the power production and the flow field in a wind farm is conducted, validating them against SCADA (Supervisory, Control And Data Acquisition) data. The three software were ORFEUS, WindSim and WAsP: ORFEUS and WAsP are linearised solvers, while WindSim is fully nonlinear. A wake model (namely a prescribed velocity deficit associated to the turbines) is used by WAsP, while ORFEUS and WindSim use the actuator-disc method to account for the turbines presence. The comparison indicates that ORFEUS and WAsP perform slightly better than WindSim in the assessment of the polar efficiency. The wakes simulated with ORFEUS appear more persistent than the ones of WindSim, which uses a two-equation closure model for the turbulence effects.

  18. Simulation and Study of Power Quality Issues in a Fixed Speed Wind Farm Substation

    PubMed Central

    Magesh, T.; Chellamuthu, C.

    2015-01-01

    Power quality issues associated with the fixed speed wind farm substation located at Coimbatore district are investigated as the wind generators are tripping frequently. The investigations are carried out using two power quality analyzers, Fluke 435 and Dranetz PX5.8, with one of them connected at group control breaker of the 110 kV feeder and the other at the selected 0.69 kV generator busbar during the period of maximum power generation. From the analysis of the recorded data it is found that sag, swell, and transients are the major events which are responsible for the tripping of the generators. In the present study, simulation models for wind, turbine, shaft, pitch mechanism, induction generator, and grid are developed using DIgSILENT. Using the turbine characteristics, a two-dimensional lookup table is designed to generate a reference pitch angle necessary to simulate the power curve of the passive stall controlled wind turbine. Various scenarios and their effects on the performance of the wind farm are studied and validated with the recorded data and waveforms. The simulation model will be useful for the designers for planning and development of the wind farm before implementation. PMID:25950016

  19. Simulation and study of power quality issues in a fixed speed wind farm substation.

    PubMed

    Magesh, T; Chellamuthu, C

    2015-01-01

    Power quality issues associated with the fixed speed wind farm substation located at Coimbatore district are investigated as the wind generators are tripping frequently. The investigations are carried out using two power quality analyzers, Fluke 435 and Dranetz PX5.8, with one of them connected at group control breaker of the 110 kV feeder and the other at the selected 0.69 kV generator busbar during the period of maximum power generation. From the analysis of the recorded data it is found that sag, swell, and transients are the major events which are responsible for the tripping of the generators. In the present study, simulation models for wind, turbine, shaft, pitch mechanism, induction generator, and grid are developed using DIgSILENT. Using the turbine characteristics, a two-dimensional lookup table is designed to generate a reference pitch angle necessary to simulate the power curve of the passive stall controlled wind turbine. Various scenarios and their effects on the performance of the wind farm are studied and validated with the recorded data and waveforms. The simulation model will be useful for the designers for planning and development of the wind farm before implementation.

  20. Spatial structure of kinetic energy spectra in LES simulations of flow in an offshore wind farm

    NASA Astrophysics Data System (ADS)

    Fruh, Wolf-Gerrit; Creech, Angus

    2017-04-01

    The evolution of wind turbine and wind farm wakes was investigated numerically for the case of Lillgrund wind farm consisting of a tightly packed array of 48 turbines. The simulations for a number of wind directions at a free wind speed of just under the rated wind speed in a neutrally stable atmosphere were carried out using Large-Eddy Simulations with the adaptive Finite-Element CFD solver Fluidity. The results were interpolated from the irregularly spaced mesh nodes onto a regular grid with comparable spatial resolution at horizontal slices at various heights. To investigate the development of the wake as the flow evolves through the array, spectra of the kinetic energy in sections perpendicular to the wind directions within the wake and to the sides of the array were calculated. This paper will present the key features and spectral slopes of the flow as a function of downstream distance from the front turbine through and beyond the array. The main focus will be on the modification of the spectra as the flow crosses a row of turbines followed by its decay in the run-up to the next row, but we will also present to wake decay of the wind farm wake downstream of the array.

  1. Effects of stored feed cropping systems and farm size on the profitability of Maine organic dairy farm simulations.

    PubMed

    Hoshide, A K; Halloran, J M; Kersbergen, R J; Griffin, T S; DeFauw, S L; LaGasse, B J; Jain, S

    2011-11-01

    United States organic dairy production has increased to meet the growing demand for organic milk. Despite higher prices received for milk, organic dairy farmers have come under increasing financial stress due to increases in concentrated feed prices over the past few years, which can make up one-third of variable costs. Market demand for milk has also leveled in the last year, resulting in some downward pressure on prices paid to dairy farmers. Organic dairy farmers in the Northeast United States have experimented with growing different forage and grain crops to maximize on-farm production of protein and energy to improve profitability. Three representative organic feed systems were simulated using the integrated farm system model for farms with 30, 120, and 220 milk cows. Increasing intensity of equipment use was represented by organic dairy farms growing only perennial sod (low) to those with corn-based forage systems, which purchase supplemental grain (medium) or which produce and feed soybeans (high). The relative profitability of these 3 organic feed systems was strongly dependent on dairy farm size. From results, we suggest smaller organic dairy farms can be more profitable with perennial sod-based rather than corn-based forage systems due to lower fixed costs from using only equipment associated with perennial forage harvest and storage. The largest farm size was more profitable using a corn-based system due to greater economies of scale for growing soybeans, corn grain, winter cereals, and corn silages. At an intermediate farm size of 120 cows, corn-based forage systems were more profitable if perennial sod was not harvested at optimum quality, corn was grown on better soils, or if milk yield was 10% higher. Delayed harvest decreased the protein and energy content of perennial sod crops, requiring more purchased grain to balance the ration and resulting in lower profits. Corn-based systems were less affected by lower perennial forage quality, as corn silage

  2. Large eddy simulation of unsteady wind farm behavior using advanced actuator disk models

    NASA Astrophysics Data System (ADS)

    Moens, Maud; Duponcheel, Matthieu; Winckelmans, Gregoire; Chatelain, Philippe

    2014-11-01

    The present project aims at improving the level of fidelity of unsteady wind farm scale simulations through an effort on the representation and the modeling of the rotors. The chosen tool for the simulations is a Fourth Order Finite Difference code, developed at Universite catholique de Louvain; this solver implements Large Eddy Simulation (LES) approaches. The wind turbines are modeled as advanced actuator disks: these disks are coupled with the Blade Element Momentum method (BEM method) and also take into account the turbine dynamics and controller. A special effort is made here to reproduce the specific wake behaviors. Wake decay and expansion are indeed initially governed by vortex instabilities. This is an information that cannot be obtained from the BEM calculations. We thus aim at achieving this by matching the large scales of the actuator disk flow to high fidelity wake simulations produced using a Vortex Particle-Mesh method. It is obtained by adding a controlled excitation at the disk. We apply this tool to the investigation of atmospheric turbulence effects on the power production and on the wake behavior at a wind farm level. A turbulent velocity field is then used as inflow boundary condition for the simulations. We gratefully acknowledge the support of GDF Suez for the fellowship of Mrs Maud Moens.

  3. Farm simulation can help adapt dairy production systems to climate change

    USDA-ARS?s Scientific Manuscript database

    Climate change is affecting the production of feed on dairy farms. Warming climates also affect the performance of dairy cattle and the interactions between feed production and animal performance. Process level simulation of dairy production systems provides a tool for whole-farm evaluation of the e...

  4. Numerical simulations of flow fields through conventionally controlled wind turbines & wind farms

    NASA Astrophysics Data System (ADS)

    Emre Yilmaz, Ali; Meyers, Johan

    2014-06-01

    In the current study, an Actuator-Line Model (ALM) is implemented in our in-house pseudo-spectral LES solver SP-WIND, including a turbine controller. Below rated wind speed, turbines are controlled by a standard-torque-controller aiming at maximum power extraction from the wind. Above rated wind speed, the extracted power is limited by a blade pitch controller which is based on a proportional-integral type control algorithm. This model is used to perform a series of single turbine and wind farm simulations using the NREL 5MW turbine. First of all, we focus on below-rated wind speed, and investigate the effect of the farm layout on the controller calibration curves. These calibration curves are expressed in terms of nondimensional torque and rotational speed, using the mean turbine-disk velocity as reference. We show that this normalization leads to calibration curves that are independent of wind speed, but the calibration curves do depend on the farm layout, in particular for tightly spaced farms. Compared to turbines in a lone-standing set-up, turbines in a farm experience a different wind distribution over the rotor due to the farm boundary-layer interaction. We demonstrate this for fully developed wind-farm boundary layers with aligned turbine arrangements at different spacings (5D, 7D, 9D). Further we also compare calibration curves obtained from full farm simulations with calibration curves that can be obtained at a much lower cost using a minimal flow unit.

  5. X-Ray Detector Simulations - Oral Presentation

    SciTech Connect

    Tina, Adrienne

    2015-08-20

    The free-electron laser at LCLS produces X-Rays that are used in several facilities. This light source is so bright and quick that we are capable of producing movies of objects like proteins. But making these movies would not be possible without a device that can detect the X-Rays and produce images. We need X-Ray cameras. The challenges LCLS faces include the X-Rays’ high repetition rate of 120 Hz, short pulses that can reach 200 femto-seconds, and extreme peak brightness. We need detectors that are compatible with this light source, but before they can be used in the facilities, they must first be characterized. My project was to do just that, by making a computer simulation program. My presentation discusses the individual detectors I simulated, the details of my program, and how my project will help determine which detector is most useful for a specific experiment.

  6. Challenges in simulating coastal effects on an offshore wind farm

    NASA Astrophysics Data System (ADS)

    van der Laan, M. P.; Peña, A.; Volker, P.; Hansen, K. S.; Sørensen, N. N.; Ott, S.; Hasager, C. B.

    2017-05-01

    The effect of a coastline on an offshore wind farm is investigated with a Reynolds-averaged Navier-Stokes (RANS) model. The trends of the RANS model compare relatively well with results from a mesoscale model and measurements of wind turbine power. In addition, challenges of modeling a large domain in RANS are discussed.

  7. New parsimonious simulation methods and tools to assess future food and environmental security of farm populations

    PubMed Central

    Antle, John M.; Stoorvogel, Jetse J.; Valdivia, Roberto O.

    2014-01-01

    This article presents conceptual and empirical foundations for new parsimonious simulation models that are being used to assess future food and environmental security of farm populations. The conceptual framework integrates key features of the biophysical and economic processes on which the farming systems are based. The approach represents a methodological advance by coupling important behavioural processes, for example, self-selection in adaptive responses to technological and environmental change, with aggregate processes, such as changes in market supply and demand conditions or environmental conditions as climate. Suitable biophysical and economic data are a critical limiting factor in modelling these complex systems, particularly for the characterization of out-of-sample counterfactuals in ex ante analyses. Parsimonious, population-based simulation methods are described that exploit available observational, experimental, modelled and expert data. The analysis makes use of a new scenario design concept called representative agricultural pathways. A case study illustrates how these methods can be used to assess food and environmental security. The concluding section addresses generalizations of parametric forms and linkages of regional models to global models. PMID:24535388

  8. Simulations of Vertical Axis Wind Turbine Farms in the Atmospheric Boundary Layer

    NASA Astrophysics Data System (ADS)

    Hezaveh, Seyed Hossein; Bou-Zeid, Elie; Lohry, Mark; Martinelli, Luigi

    2014-11-01

    Wind power is an abundant and clean source of energy that is increasingly being tapped to reduce the environmental footprint of anthropogenic activities. The vertical axis wind turbine (VAWT) technology is now being revisited due to some important advantages over horizontal axis wind turbines (HAWTS) that are particularly important for farms deployed offshore or in complex terrain. In this talk, we will present the implementation and testing of an actuator line model (ALM) for VAWTs in a large eddy simulation (LES) code for the atmospheric boundary layer, with the aim of optimizing large VAWT wind farm configurations. The force coefficients needed for the ALM are here obtained from blade resolving RANS simulations of individual turbines for each configuration. Comparison to various experimental results show that the model can very successfully reproduce observed wake characteristic. The influence of VAWT design parameters such as solidity, height to radius ratio, and tip speed ratio (TSR) on these wake characteristics, particularly the velocity deficit profile, is then investigated.

  9. Large-Eddy Simulation of Waked Turbines in a Scaled Wind Farm Facility

    NASA Astrophysics Data System (ADS)

    Wang, J.; McLean, D.; Campagnolo, F.; Yu, T.; Bottasso, C. L.

    2017-05-01

    The aim of this paper is to present the numerical simulation of waked scaled wind turbines operating in a boundary layer wind tunnel. The simulation uses a LES-lifting-line numerical model. An immersed boundary method in conjunction with an adequate wall model is used to represent the effects of both the wind turbine nacelle and tower, which are shown to have a considerable effect on the wake behavior. Multi-airfoil data calibrated at different Reynolds numbers are used to account for the lift and drag characteristics at the low and varying Reynolds conditions encountered in the experiments. The present study focuses on low turbulence inflow conditions and inflow non-uniformity due to wind tunnel characteristics, while higher turbulence conditions are considered in a separate study. The numerical model is validated by using experimental data obtained during test campaigns conducted with the scaled wind farm facility. The simulation and experimental results are compared in terms of power capture, rotor thrust, downstream velocity profiles and turbulence intensity.

  10. Atmospheric stability effects on wind farm performance using large-eddy simulation

    NASA Astrophysics Data System (ADS)

    Archer, C. L.; Ghaisas, N.; Xie, S.

    2014-12-01

    Atmospheric stability has been recently found to have significant impacts on wind farm performance, especially since offshore and onshore wind farms are known to operate often under non-neutral conditions. Recent field observations have revealed that changes in stability are accompanied by changes in wind speed, direction, and turbulent kinetic energy (TKE). In order to isolate the effects of stability, large-eddy simulations (LES) are performed under neutral, stable, and unstable conditions, keeping the wind speed and direction unchanged at a fixed height. The Lillgrund wind farm, comprising of 48 turbines, is studied in this research with the Simulator for Offshore/Onshore Wind Farm Applications (SOWFA) developed by the National Renewable Energy Laboratory. Unlike most previous numerical simulations, this study does not impose periodic boundary conditions and therefore is ideal for evaluating the effects of stability in large, but finite, wind farms. Changes in power generation, velocity deficit, rate of wake recovery, TKE, and surface temperature are quantified as a function of atmospheric stability. The sensitivity of these results to wind direction is also discussed.

  11. Shifted periodic boundary conditions for large-eddy simulation of wind farms

    NASA Astrophysics Data System (ADS)

    Munters, Wim; Meneveau, Charles; Meyers, Johan

    2015-11-01

    In wall-bounded turbulent flow simulations, periodic boundary conditions combined with insufficiently long domains lead to persistent spanwise locking of large-scale turbulent structures. In the context of wind-farm large-eddy simulations, this effect induces artificial spanwise inhomogeneities in the time-averaged local wind conditions as seen by the wind turbines, leading to spurious differences in power prediction between otherwise equivalent columns of wind turbines in a wind farm (a column is defined here as a set of turbines parallel to the mean flow direction). We propose a shifted periodic boundary condition that eliminates this effect without the need for excessive streamwise domain lengths. Instead of straightforwardly reintroducing the velocity from the outlet plane back at the inlet, as in classic periodic boundary conditions, this plane is first shifted in the spanwise direction by a predefined and constant distance. The method is tested based on a set of direct numerical simulations of a turbulent channel flow, and large-eddy simulations of a high Reynolds number rough-wall half-channel flow. Finally, we apply the method in a precursor simulation, generating inlet conditions for a spatially developing wind-farm boundary layer. WM and JM are supported by the ERC (ActiveWindFarms, grant no: 306471). CM acknowledges support by the NSF (grant IIA-1243482, the WINDINSPIRE project).

  12. Multitasking simulation: Present application and future directions.

    PubMed

    Adams, Traci Nicole; Rho, Jason C

    2017-02-01

    The Accreditation Council for Graduate Medical Education lists multi-tasking as a core competency in several medical specialties due to increasing demands on providers to manage the care of multiple patients simultaneously. Trainees often learn multitasking on the job without any formal curriculum, leading to high error rates. Multitasking simulation training has demonstrated success in reducing error rates among trainees. Studies of multitasking simulation demonstrate that this type of simulation is feasible, does not hinder the acquisition of procedural skill, and leads to better performance during subsequent periods of multitasking. Although some healthcare agencies have discouraged multitasking due to higher error rates among multitasking providers, it cannot be eliminated entirely in settings such as the emergency department in which providers care for more than one patient simultaneously. Simulation can help trainees to identify situations in which multitasking is inappropriate, while preparing them for situations in which multitasking is inevitable.

  13. Surface Operations Simulator and Scheduler (SOSS) Presentation

    NASA Technical Reports Server (NTRS)

    Zhu, Zhifan

    2016-01-01

    NASA - KAIA (Korea Agency for Infrastructure Technology Advancement) - KARI (Korea Aerospace Research Institute) collaboration surface air traffic management research has been ongoing since May 2015. In the first year collaboration, NASA's SOSS software has been transferred to KAIA and KARI teams to provide fast time simulation capability. Incheon International Airport model has been developed for SOSS.

  14. NASA Center for Climate Simulation (NCCS) Presentation

    NASA Technical Reports Server (NTRS)

    Webster, William P.

    2012-01-01

    The NASA Center for Climate Simulation (NCCS) offers integrated supercomputing, visualization, and data interaction technologies to enhance NASA's weather and climate prediction capabilities. It serves hundreds of users at NASA Goddard Space Flight Center, as well as other NASA centers, laboratories, and universities across the US. Over the past year, NCCS has continued expanding its data-centric computing environment to meet the increasingly data-intensive challenges of climate science. We doubled our Discover supercomputer's peak performance to more than 800 teraflops by adding 7,680 Intel Xeon Sandy Bridge processor-cores and most recently 240 Intel Xeon Phi Many Integrated Core (MIG) co-processors. A supercomputing-class analysis system named Dali gives users rapid access to their data on Discover and high-performance software including the Ultra-scale Visualization Climate Data Analysis Tools (UV-CDAT), with interfaces from user desktops and a 17- by 6-foot visualization wall. NCCS also is exploring highly efficient climate data services and management with a new MapReduce/Hadoop cluster while augmenting its data distribution to the science community. Using NCCS resources, NASA completed its modeling contributions to the Intergovernmental Panel on Climate Change (IPCG) Fifth Assessment Report this summer as part of the ongoing Coupled Modellntercomparison Project Phase 5 (CMIP5). Ensembles of simulations run on Discover reached back to the year 1000 to test model accuracy and projected climate change through the year 2300 based on four different scenarios of greenhouse gases, aerosols, and land use. The data resulting from several thousand IPCC/CMIP5 simulations, as well as a variety of other simulation, reanalysis, and observationdatasets, are available to scientists and decision makers through an enhanced NCCS Earth System Grid Federation Gateway. Worldwide downloads have totaled over 110 terabytes of data.

  15. Data-driven RANS for simulations of large wind farms

    NASA Astrophysics Data System (ADS)

    Iungo, G. V.; Viola, F.; Ciri, U.; Rotea, M. A.; Leonardi, S.

    2015-06-01

    In the wind energy industry there is a growing need for real-time predictions of wind turbine wake flows in order to optimize power plant control and inhibit detrimental wake interactions. To this aim, a data-driven RANS approach is proposed in order to achieve very low computational costs and adequate accuracy through the data assimilation procedure. The RANS simulations are implemented with a classical Boussinesq hypothesis and a mixing length turbulence closure model, which is calibrated through the available data. High-fidelity LES simulations of a utility-scale wind turbine operating with different tip speed ratios are used as database. It is shown that the mixing length model for the RANS simulations can be calibrated accurately through the Reynolds stress of the axial and radial velocity components, and the gradient of the axial velocity in the radial direction. It is found that the mixing length is roughly invariant in the very near wake, then it increases linearly with the downstream distance in the diffusive region. The variation rate of the mixing length in the downstream direction is proposed as a criterion to detect the transition between near wake and transition region of a wind turbine wake. Finally, RANS simulations were performed with the calibrated mixing length model, and a good agreement with the LES simulations is observed.

  16. Simulation of Intra- or transboundary surface-water-rights hierarchies using the farm process for MODFLOW-2000

    USGS Publications Warehouse

    Schmid, W.; Hanson, R.T.

    2007-01-01

    Water-rights driven surface-water allocations for irrigated agriculture can be simulated using the farm process for MODFLOW-2000. This paper describes and develops a model, which simulates routed surface-water deliveries to farms limited by streamflow, equal-appropriation allotments, or a ranked prior-appropriation system. Simulated diversions account for deliveries to all farms along a canal according to their water-rights ranking and for conveyance losses and gains. Simulated minimum streamflow requirements on diversions help guarantee supplies to senior farms located on downstream diverting canals. Prior appropriation can be applied to individual farms or to groups of farms modeled as "virtual farms" representing irrigation districts, irrigated regions in transboundary settings, or natural vegetation habitats. The integrated approach of jointly simulating canal diversions, surface-water deliveries subject to water-rights constraints, and groundwater allocations is verified on numerical experiments based on a realistic, but hypothetical, system of ranked virtual farms. Results are discussed in light of transboundary water appropriation and demonstrate the approach's suitability for simulating effects of water-rights hierarchies represented by international treaties, interstate stream compacts, intrastate water rights, or ecological requirements. ?? 2007 ASCE.

  17. Large-eddy simulations of wind farm production and long distance wakes

    NASA Astrophysics Data System (ADS)

    Eriksson, O.; Nilsson, K.; Breton, S.-P.; Ivanell, S.

    2015-06-01

    The future development of offshore wind power will include many wind farms built in the same areas. It is known that wind farms produce long distance wakes, which means that we will see more occasions of farm to farm interaction, namely one wind farm operating in the wake of another wind farm. This study investigates how to perform accurate power predictions on large wind farms and how to assess the long distance wakes generated by these farms. The focus of this paper is the production's and wake's sensitivity to the extension of the grid as well as the turbulence when using Large-eddy simulations (LES) with pregenerated Mann turbulence. The aim is to determine an optimal grid which minimizes blockage effects and ensures constant resolution in the entire wake region at the lowest computational cost. The simulations are first performed in the absence of wind turbines in order to assess how the atmospheric turbulence and wind profile are evolving downstream (up to 12,000 m behind the position where the turbulence is imposed). In the second step, 10 turbines are added in the domain (using an actuator disc method) and their production is analyzed alongside the mean velocities in the domain. The blockage effects are tested using grids with different vertical extents. An equidistant region is used in order to ensure high resolution in the wake region. The importance of covering the entire wake structure inside the equidistant region is analyzed by decreasing the size of this region. In this step, the importance of the lateral size of the Mann turbulence box is also analyzed. In the results it can be seen that the flow is acceptably preserved through the empty domain if a larger turbulence box is used. The relative production is increased (due to blockage effects) for the last turbines using a smaller vertical domain, increased for a lower or narrower equidistant region (due to the smearing of the wake in the stretched area) and decreased when using a smaller turbulence

  18. A beef herd model for simulating feed intake, animal performance, and manure excretion in farm systems.

    PubMed

    Rotz, C A; Buckmaster, D R; Comerford, J W

    2005-01-01

    A beef herd submodel was created for integration with other farm components to form a whole-farm model capable of simulating a wide range of beef production systems. This herd submodel determined the best available feed or feed mix to meet the fiber, energy, and protein requirements for each of up to six animal groups on the farm. The groups comprised any combination of cows, nursing calves, young heifers, yearling heifers, stockers, and finishing cattle. Protein, energy, and mineral requirements were determined for each group using the Cornell Net Carbohydrate and Protein System, Level 1. Diets were formulated to meet these requirements with available feeds, and the resulting feed intake, growth, and manure DM and nutrient (N, P, and K) excretions were predicted. Required feed characteristics included CP, ruminally degradable protein, acid detergent insoluble protein, NDF, P, and K concentrations. Feed intake was predicted by considering energy intake, potentially limited by fill, and exceeding a minimum roughage requirement. Fill and roughage limits were functions of feed NDF concentrations adjusted to consider particle size distribution and the relative rate of ruminal digestibility or the physical effectiveness of the fiber. The herd submodel was verified to predict feed intakes, nutrient requirements, diets, and manure excretions similar to those recommended or measured for beef animals. Incorporation of the beef herd submodel with other farm components, including crop growth (alfalfa, grass, corn, small grain, and soybean), harvest, storage, feeding, grazing, and manure handling, provided the Integrated Farm System Model. This comprehensive farm-simulation model is a useful research and teaching tool for evaluating and comparing the long-term performance, economics, and environmental impact of beef, dairy, and crop production systems.

  19. Simulation based study of the effect of ocean waves on floating wind farm

    NASA Astrophysics Data System (ADS)

    Yang, Di; Meneveau, Charles; Shen, Lian

    2012-11-01

    A hybrid numerical capability is developed for the simulation of floating wind farm offshore, in which large-eddy simulation is performed for wind turbulence, and a potential flow based method is used for the simulation of ocean wavefield. The wind and wave simulations are coupled through a two-way feedback scheme. The effect of wind turbines on the wind field is represented by an actuator disk model. A variety of fully-developed and fetch-limited wind-sea conditions are considered in the study. The simulation results indicate that the offshore wind farm obtains a higher wind power extraction rate under the fully-developed wind-sea condition compared with the fetch-limited condition. This higher extraction rate is caused by the faster propagating waves and the lower sea-surface resistance on the wind when the wind-seas are fully developed. Such wave effect becomes more prominent when the turbine density of the wind farm increases. DY and LS acknowledge the support of NSF-CBET-1133700. CM acknowledges the support of NSF-CBET-1133800 and NSF-AGS-1045189.

  20. Wind power forecasting for a real onshore wind farm on complex terrain using WRF high resolution simulations.

    NASA Astrophysics Data System (ADS)

    Ángel Prósper Fernández, Miguel; Casal, Carlos Otero; Canoura Fernández, Felipe; Miguez-Macho, Gonzalo

    2017-04-01

    Regional meteorological models are becoming a generalized tool for forecasting wind resource, due to their capacity to simulate local flow dynamics impacting wind farm production. This study focuses on the production forecast and validation of a real onshore wind farm using high horizontal and vertical resolution WRF (Weather Research and Forecasting) model simulations. The wind farm is located in Galicia, in the northwest of Spain, in a complex terrain region with high wind resource. Utilizing the Fitch scheme, specific for wind farms, a period of one year is simulated with a daily operational forecasting set-up. Power and wind predictions are obtained and compared with real data provided by the management company. Results show that WRF is able to yield good wind power operational predictions for this kind of wind farms, due to a good representation of the planetary boundary layer behaviour of the region and the good performance of the Fitch scheme under these conditions.

  1. Simulating the Distribution of Individual Livestock Farms and Their Populations in the United States: An Example Using Domestic Swine (Sus scrofa domesticus) Farms.

    PubMed

    Burdett, Christopher L; Kraus, Brian R; Garza, Sarah J; Miller, Ryan S; Bjork, Kathe E

    2015-01-01

    Livestock distribution in the United States (U.S.) can only be mapped at a county-level or worse resolution. We developed a spatial microsimulation model called the Farm Location and Agricultural Production Simulator (FLAPS) that simulated the distribution and populations of individual livestock farms throughout the conterminous U.S. Using domestic pigs (Sus scrofa domesticus) as an example species, we customized iterative proportional-fitting algorithms for the hierarchical structure of the U.S. Census of Agriculture and imputed unpublished state- or county-level livestock population totals that were redacted to ensure confidentiality. We used a weighted sampling design to collect data on the presence and absence of farms and used them to develop a national-scale distribution model that predicted the distribution of individual farms at a 100 m resolution. We implemented microsimulation algorithms that simulated the populations and locations of individual farms using output from our imputed Census of Agriculture dataset and distribution model. Approximately 19% of county-level pig population totals were unpublished in the 2012 Census of Agriculture and needed to be imputed. Using aerial photography, we confirmed the presence or absence of livestock farms at 10,238 locations and found livestock farms were correlated with open areas, cropland, and roads, and also areas with cooler temperatures and gentler topography. The distribution of swine farms was highly variable, but cross-validation of our distribution model produced an area under the receiver-operating characteristics curve value of 0.78, which indicated good predictive performance. Verification analyses showed FLAPS accurately imputed and simulated Census of Agriculture data based on absolute percent difference values of < 0.01% at the state-to-national scale, 3.26% for the county-to-state scale, and 0.03% for the individual farm-to-county scale. Our output data have many applications for risk management of

  2. Simulating the Distribution of Individual Livestock Farms and Their Populations in the United States: An Example Using Domestic Swine (Sus scrofa domesticus) Farms

    PubMed Central

    Garza, Sarah J.; Miller, Ryan S.

    2015-01-01

    Livestock distribution in the United States (U.S.) can only be mapped at a county-level or worse resolution. We developed a spatial microsimulation model called the Farm Location and Agricultural Production Simulator (FLAPS) that simulated the distribution and populations of individual livestock farms throughout the conterminous U.S. Using domestic pigs (Sus scrofa domesticus) as an example species, we customized iterative proportional-fitting algorithms for the hierarchical structure of the U.S. Census of Agriculture and imputed unpublished state- or county-level livestock population totals that were redacted to ensure confidentiality. We used a weighted sampling design to collect data on the presence and absence of farms and used them to develop a national-scale distribution model that predicted the distribution of individual farms at a 100 m resolution. We implemented microsimulation algorithms that simulated the populations and locations of individual farms using output from our imputed Census of Agriculture dataset and distribution model. Approximately 19% of county-level pig population totals were unpublished in the 2012 Census of Agriculture and needed to be imputed. Using aerial photography, we confirmed the presence or absence of livestock farms at 10,238 locations and found livestock farms were correlated with open areas, cropland, and roads, and also areas with cooler temperatures and gentler topography. The distribution of swine farms was highly variable, but cross-validation of our distribution model produced an area under the receiver-operating characteristics curve value of 0.78, which indicated good predictive performance. Verification analyses showed FLAPS accurately imputed and simulated Census of Agriculture data based on absolute percent difference values of < 0.01% at the state-to-national scale, 3.26% for the county-to-state scale, and 0.03% for the individual farm-to-county scale. Our output data have many applications for risk management of

  3. Multiscale aeroelastic simulations of large wind farms in the atmospheric boundary layer

    NASA Astrophysics Data System (ADS)

    Vitsas, Athanasios; Meyers, Johan

    2016-09-01

    In large wind farms, the turbulence induced by each turbine results in high overall turbulence levels that can be detrimental for downstream wind turbine components. In the current study, we scrutinize structural loads and dynamics, and their correlation to turbulent flow structures by conducting aeroelastic simulations in wind farms. To this end, a pseudospectral large-eddy simulation solver is coupled with a multibody dynamics module in a multiscale framework. The multirate approach leads us naturally to the development of an aeroelastic actuator sector model that represents the wind turbine forces on the flow. This makes it computationally feasible to simulate long time horizons of the two-way coupled aeroelastic system. Hence, it allows us to look at the interaction of the turbine structure with the turbulent boundary layer and the wakes of multiple turbine arrays, and to get estimates of damage equivalent loads and structural loading statistics, as longer time series are available. Results are shown for two typical wind farm layouts, i.e. aligned and staggered, for above-rated flow regimes.

  4. Interactive computer simulation of dairy farm systems as a method for making energy management decisions

    SciTech Connect

    Hewett, E.J. III

    1983-01-01

    To facilitate management decisions an analytical model was developed to predict energy and labor requirements and costs for milking and feed handling systems. The Dairy Farm Simulation Model was based on detailed time and motion studies, and energy audits of 21 dairy farms in Michigan. Data included labor hours and energy consumption per month for each operation required for milking and feed handling and charges based on Detroit Edison electrical rate schedules. The result of optimizing the electrical rate charges for simulated milking systems is indicated by the Time-of-Day Rate Schedule which provides the lowest cost to farm operators willing to adjust milking times. Simulation of mobile and stationary feeding systems for six herd sizes includes calculations of capital investment and operating costs in addition to labor and energy cost. Results indicate that mobile systems required a lower investment cost while stationary systems realize lower energy costs. Labor requirements per cow decreased as herd size increased for mobile systems, but remained the same for stationary systems regardless of herd size. The energy required to operate each system, based on the number of oil barrel equivalents, indicates the stationary system required less energy for herd sizes up to and including 150 cows, while mobile systems indicate a lower energy requirement for herd sizes greater than 150 cows. In general, no single system emerged as the best, rather it depended on the operator's personal preference.

  5. Simple Exhibits, Effective Learning: Presenting the United Farm Workers' Experience on the World Wide Web.

    ERIC Educational Resources Information Center

    Golodner, Daniel

    2002-01-01

    Describes the design of an online exhibit about the history of the United Farm Workers union that was created on the World Wide Web by the Walter P. Reuther Library/Archives of Labor and Urban History. Discusses Web design, hypertext links, and ease of navigation. (Author/LRW)

  6. Farm Living.

    ERIC Educational Resources Information Center

    Marcoux, Mary F.

    1990-01-01

    Described are activities using ants. Ant hunting, a list of books on the topic, information, and ant farming are included. The procedures for assembling and maintenance of an ant farm are presented. (KR)

  7. Regional climate model simulations indicate limited climatic impacts by operational and planned European wind farms

    NASA Astrophysics Data System (ADS)

    Vautard, Robert; Thais, Françoise; Tobin, Isabelle; Bréon, François-Marie; de Lavergne, Jean-Guy Devezeaux; Colette, Augustin; Yiou, Pascal; Ruti, Paolo Michele

    2014-02-01

    The rapid development of wind energy has raised concerns about environmental impacts. Temperature changes are found in the vicinity of wind farms and previous simulations have suggested that large-scale wind farms could alter regional climate. However, assessments of the effects of realistic wind power development scenarios at the scale of a continent are missing. Here we simulate the impacts of current and near-future wind energy production according to European Union energy and climate policies. We use a regional climate model describing the interactions between turbines and the atmosphere, and find limited impacts. A statistically significant signal is only found in winter, with changes within ±0.3 °C and within 0-5% for precipitation. It results from the combination of local wind farm effects and changes due to a weak, but robust, anticyclonic-induced circulation over Europe. However, the impacts remain much weaker than the natural climate interannual variability and changes expected from greenhouse gas emissions.

  8. Regional climate model simulations indicate limited climatic impacts by operational and planned European wind farms.

    PubMed

    Vautard, Robert; Thais, Françoise; Tobin, Isabelle; Bréon, François-Marie; Devezeaux de Lavergne, Jean-Guy; Colette, Augustin; Yiou, Pascal; Ruti, Paolo Michele

    2014-01-01

    The rapid development of wind energy has raised concerns about environmental impacts. Temperature changes are found in the vicinity of wind farms and previous simulations have suggested that large-scale wind farms could alter regional climate. However, assessments of the effects of realistic wind power development scenarios at the scale of a continent are missing. Here we simulate the impacts of current and near-future wind energy production according to European Union energy and climate policies. We use a regional climate model describing the interactions between turbines and the atmosphere, and find limited impacts. A statistically significant signal is only found in winter, with changes within ±0.3 °C and within 0-5% for precipitation. It results from the combination of local wind farm effects and changes due to a weak, but robust, anticyclonic-induced circulation over Europe. However, the impacts remain much weaker than the natural climate interannual variability and changes expected from greenhouse gas emissions.

  9. Electromagnetic Simulation of the Near-Field Distribution around a Wind Farm

    DOE PAGES

    Yang, Shang-Te; Ling, Hao

    2013-01-01

    An efficienmore » t approach to compute the near-field distribution around and within a wind farm under plane wave excitation is proposed. To make the problem computationally tractable, several simplifying assumptions are made based on the geometry problem. By comparing the approximations against full-wave simulations at 500 MHz, it is shown that the assumptions do not introduce significant errors into the resulting near-field distribution. The near fields around a 3 × 3 wind farm are computed using the developed methodology at 150 MHz, 500 MHz, and 3 GHz. Both the multipath interference patterns and the forward shadows are predicted by the proposed method.« less

  10. Simulant Development for Hanford Tank Farms Double Valve Isolation (DVI) Valves Testing

    SciTech Connect

    Wells, Beric E.

    2012-12-21

    Leakage testing of a representative sample of the safety-significant isolation valves for Double Valve Isolation (DVI) in an environment that simulates the abrasive characteristics of the Hanford Tank Farms Waste Transfer System during waste feed delivery to the Waste Treatment and Immobilization Plant (WTP) is to be conducted. The testing will consist of periodic leak performed on the DVI valves after prescribed numbers of valve cycles (open and close) in a simulated environment representative of the abrasive properties of the waste and the Waste Transfer System. The valve operations include exposure to cycling conditions that include gravity drain and flush operation following slurry transfer. The simulant test will establish the performance characteristics and verify compliance with the Documented Safety Analysis. Proper simulant development is essential to ensure that the critical process streams characteristics are represented, National Research Council report “Advice on the Department of Energy's Cleanup Technology Roadmap: Gaps and Bridges”

  11. Field Test Design Simulations of Pore-Water Extraction for the SX Tank Farm

    SciTech Connect

    Truex, Michael J.; Oostrom, Martinus

    2013-09-01

    A proof of principle test of pore water extraction is being performed by Washington River Protection Solutions for the U.S. Department of Energy, Office of River Protection. This test is being conducted to meet the requirements of Hanford Federal Facility Agreement and Consent Order (HFFACO) (Ecology et al. 1989) Milestone M 045-20, and is described in RPP-PLAN-53808, 200 West Area Tank Farms Interim Measures Investigation Work Plan. To support design of this test, numerical simulations were conducted to help define equipment and operational parameters. The modeling effort builds from information collected in laboratory studies and from field characterization information collected at the test site near the Hanford Site 241-SX Tank Farm. Numerical simulations were used to evaluate pore-water extraction performance as a function of the test site properties and for the type of extraction well configuration that can be constructed using the direct-push installation technique. Output of simulations included rates of water and soil-gas production as a function of operational conditions for use in supporting field equipment design. The simulations also investigated the impact of subsurface heterogeneities in sediment properties and moisture distribution on pore-water extraction performance. Phenomena near the extraction well were also investigated because of their importance for pore-water extraction performance.

  12. Extreme rainfall in Serbia, May 2014, simulation using WRF NMM and RainFARM: DRIHM project

    NASA Astrophysics Data System (ADS)

    Dekić, Ljiljana; Mihalović, Ana; Dimitrijević, Vladimir; Rebora, Nicola; Parodi, Antonio

    2015-04-01

    Extreme rainfall in Serbia, May 2014, simulation using WRF NMM and RainFARM: DRIHM project Ljiljana Dekić (1), Ana Mihalović (1), Vladimir Dimitrijević (1), Nicola Rebora (2), Antonio Parodi (2) (1)Republic HydroMeteorological Service of Serbia, Belgrade, Serbia, (2)CIMA Research Foundation, Savona, Italy In May 2014 Balkan region was affected with the continuous heavy rainfall, the heaviest in 120 years of recording observation, causing extensive flooding. Serbia suffered human casualties, huge infrastructure and industrial destruction and agricultural damage. Cyclone development and trajectory was very well predicted by RHMSS operational WRF NMM numerical model but extreme precipitation was not possible to predict with sufficient precision. Simulation of extreme rainfall situations using different numerical weather prediction models can indicate weakness of the model and point out importance of specified physical approach and parameterization schemes. The FP7 Distributed Research Infrastructure for Hydro-Meteorology DRIHM project gives a framework for using different models in forecasting extreme weather events. One of the DRIHM component is Rainfall Filtered Autoregressive Model RainFARM for stochastic rainfall downscaling. Objective of the DRIHM project was developing of standards and conversion of the data for seamless use of meteorological and hydrological models in flood prediction. This paper describes numerical tests and results of WRF NMM nonhydrostatic model and RainFARM downscaling applied on WRF NMM outputs. Different physics options in WRF NMM and their influence on precipitation amount were investigated. RainFARM was applied on every physical option with downscaling from 4km to 500m and 100m horizontal resolution and 100 ensemble members. We analyzed locations on the catchments in Serbia where flooding was the strongest and the most destructive. Statistical evaluation of ensemble output gives new insight into the sub scale precipitation

  13. High-resolution computational algorithms for simulating offshore wind turbines and farms: Model development and validation

    SciTech Connect

    Calderer, Antoni; Yang, Xiaolei; Angelidis, Dionysios; Feist, Chris; Guala, Michele; Ruehl, Kelley; Guo, Xin; Boomsma, Aaron; Shen, Lian; Sotiropoulos, Fotis

    2015-10-30

    The present project involves the development of modeling and analysis design tools for assessing offshore wind turbine technologies. The computational tools developed herein are able to resolve the effects of the coupled interaction of atmospheric turbulence and ocean waves on aerodynamic performance and structural stability and reliability of offshore wind turbines and farms. Laboratory scale experiments have been carried out to derive data sets for validating the computational models.

  14. Simulation of Conjunctive Agricultural Water Use with the new FARM package for MODFLOW-2000

    NASA Astrophysics Data System (ADS)

    Schmidt, W.; Hanson, R. T.; Maddock, T.

    2004-12-01

    A new Farm Package (FMP) was developed for the U.S. Geological Survey's groundwater modeling program, MODFLOW-2000 (MF2K), to estimate irrigation water allocations from conjunctively used surface and ground water. The FMP package dynamically integrates irrigation water demand, surface and ground-water supply, and return flow from excess irrigation. Routed surface-water delivery is optional, but can be simulated by coupling the FMP package with the Streamflow Routing Package (SFR1). Applying MF2K with the FMP and SFR1 packages facilitates estimating the allocation of surface and ground-water to farms for simulations of historical calibration or future projections directly within MF2K. These simulations also can be useful for assessing water rights issues and operational decisions as well as for non-drought versus drought supply and demand strategies. Estimates of historic pumpage may be particularly useful where well pumpage has not been recorded, such as agivulture in the southwestern United States. Estimates of future pumpage may be facilitated through the use of climate-model predictions to generate forecasts of potential water supply and demand for irrigation. Legal questions such as adjudications and appropriative water rights also could be assessed with simulations that use the FMP package in areas where there is a history of land use but no direct or complete record of water use. Operational decision in irrigation management depends on the ability to estimate conjunctively used surface-water and groundwater allocations just prior to or during the growing season. Conjunctive management of surface and ground-water is especially needed for periods when the proposed water supply is thought to be insufficient to meet the water demand. Simulations with the FMP package offer several choices of drought policy scenarios, such as acreage optimization that facilitates assessing an economically optimal conjunctive management. The FMP package maintains a dual mass balance

  15. Coupling dairy manure storage with injection to improve nitrogen management: whole-farm simulation using the integrated farm system Model

    USDA-ARS?s Scientific Manuscript database

    Application of livestock manure to farm soils represents a priority nutrient management concern in the Chesapeake Bay Watershed. Historically strong emphasis has been placed on adding manure storage to dairy operations, and, there has been recognition that manure application methods can be improved....

  16. Farm simulation: a tool for evaluating the mitigation of greenhouse gas emissions and the adaptation of dairy production to climate change

    USDA-ARS?s Scientific Manuscript database

    Process-level modeling at the farm scale provides a tool for evaluating both strategies for mitigating greenhouse gas emissions and strategies for adapting to climate change. The Integrated Farm System Model (IFSM) simulates representative crop, beef or dairy farms over many years of weather to pred...

  17. Automated Comparison of Building Energy Simulation Engines (Presentation)

    SciTech Connect

    Polly, B.; Horowitz, S.; Booten, B.; Kruis, N.; Christensen, C.

    2012-08-01

    This presentation describes the BEopt comparative test suite, which is a tool that facilitates the automated comparison of building energy simulation engines. It also demonstrates how the test suite is improving the accuracy of building energy simulation programs. Building energy simulation programs inform energy efficient design for new homes and energy efficient upgrades for existing homes. Stakeholders rely on accurate predictions from simulation programs. Previous research indicates that software tends to over-predict energy usage for poorly-insulated leaky homes. NREL is identifying, investigating, and resolving software inaccuracy issues. Comparative software testing is one method of many that NREL uses to identify potential software issues.

  18. Simulating the evolution of glyphosate resistance in grains farming in northern Australia

    PubMed Central

    Thornby, David F.; Walker, Steve R.

    2009-01-01

    Background and Aims The evolution of resistance to herbicides is a substantial problem in contemporary agriculture. Solutions to this problem generally consist of the use of practices to control the resistant population once it evolves, and/or to institute preventative measures before populations become resistant. Herbicide resistance evolves in populations over years or decades, so predicting the effectiveness of preventative strategies in particular relies on computational modelling approaches. While models of herbicide resistance already exist, none deals with the complex regional variability in the northern Australian sub-tropical grains farming region. For this reason, a new computer model was developed. Methods The model consists of an age- and stage-structured population model of weeds, with an existing crop model used to simulate plant growth and competition, and extensions to the crop model added to simulate seed bank ecology and population genetics factors. Using awnless barnyard grass (Echinochloa colona) as a test case, the model was used to investigate the likely rate of evolution under conditions expected to produce high selection pressure. Key Results Simulating continuous summer fallows with glyphosate used as the only means of weed control resulted in predicted resistant weed populations after approx. 15 years. Validation of the model against the paddock history for the first real-world glyphosate-resistant awnless barnyard grass population shows that the model predicted resistance evolution to within a few years of the real situation. Conclusions This validation work shows that empirical validation of herbicide resistance models is problematic. However, the model simulates the complexities of sub-tropical grains farming in Australia well, and can be used to investigate, generate and improve glyphosate resistance prevention strategies. PMID:19567415

  19. Simulating the evolution of glyphosate resistance in grains farming in northern Australia.

    PubMed

    Thornby, David F; Walker, Steve R

    2009-09-01

    The evolution of resistance to herbicides is a substantial problem in contemporary agriculture. Solutions to this problem generally consist of the use of practices to control the resistant population once it evolves, and/or to institute preventative measures before populations become resistant. Herbicide resistance evolves in populations over years or decades, so predicting the effectiveness of preventative strategies in particular relies on computational modelling approaches. While models of herbicide resistance already exist, none deals with the complex regional variability in the northern Australian sub-tropical grains farming region. For this reason, a new computer model was developed. The model consists of an age- and stage-structured population model of weeds, with an existing crop model used to simulate plant growth and competition, and extensions to the crop model added to simulate seed bank ecology and population genetics factors. Using awnless barnyard grass (Echinochloa colona) as a test case, the model was used to investigate the likely rate of evolution under conditions expected to produce high selection pressure. Simulating continuous summer fallows with glyphosate used as the only means of weed control resulted in predicted resistant weed populations after approx. 15 years. Validation of the model against the paddock history for the first real-world glyphosate-resistant awnless barnyard grass population shows that the model predicted resistance evolution to within a few years of the real situation. This validation work shows that empirical validation of herbicide resistance models is problematic. However, the model simulates the complexities of sub-tropical grains farming in Australia well, and can be used to investigate, generate and improve glyphosate resistance prevention strategies.

  20. Anisotropy stress invariants of a large eddy simulation during a diurnal cycle for very large wind farms

    NASA Astrophysics Data System (ADS)

    Cal, Raúl; Ali, Naseem; Hamilton, Nicholas; Cortina, Gerard; Calaf, Marc

    2016-11-01

    Reynolds stress invariants of the turbulent flow within large wind farms under different atmospheric flow stratification (stable, unstable and neutral); cases without turbines is also evaluated. Lumley triangle and barycentric map are used to quantify the anisotropic stress tensor within the wind farm and atmospheric boundary layer. Dependent on the thermal stratification, the unstable and neutral cases of the wind farm and no wind farm display the minimum second invariant in contrast to the stable case that shows the maximum invariants. Scaled color is used to present the invariant as a function of domain height. The unstable stratification approaches the isotropy limit at high layers of the domain and the stable stratification leads the turbulence flow to be one component flow. The principle eigenvalues are also shown, where they show its effects on the vicinity of the swept area of the rotor. Finally, spheroid visualization is pursued to understand and interpret the realizable turbulence flow within the wind farm and atmospheric boundary layer.

  1. Understanding the Impacts of Soil, Climate, and Farming Practices on Soil Organic Carbon Sequestration: A Simulation Study in Australia.

    PubMed

    Godde, Cécile M; Thorburn, Peter J; Biggs, Jody S; Meier, Elizabeth A

    2016-01-01

    Carbon sequestration in agricultural soils has the capacity to mitigate greenhouse gas emissions, as well as to improve soil biological, physical, and chemical properties. The review of literature pertaining to soil organic carbon (SOC) dynamics within Australian grain farming systems does not enable us to conclude on the best farming practices to increase or maintain SOC for a specific combination of soil and climate. This study aimed to further explore the complex interactions of soil, climate, and farming practices on SOC. We undertook a modeling study with the Agricultural Production Systems sIMulator modeling framework, by combining contrasting Australian soils, climates, and farming practices (crop rotations, and management within rotations, such as fertilization, tillage, and residue management) in a factorial design. This design resulted in the transposition of contrasting soils and climates in our simulations, giving soil-climate combinations that do not occur in the study area to help provide insights into the importance of the climate constraints on SOC. We statistically analyzed the model's outputs to determinate the relative contributions of soil parameters, climate, and farming practices on SOC. The initial SOC content had the largest impact on the value of SOC, followed by the climate and the fertilization practices. These factors explained 66, 18, and 15% of SOC variations, respectively, after 80 years of constant farming practices in the simulation. Tillage and stubble management had the lowest impacts on SOC. This study highlighted the possible negative impact on SOC of a chickpea phase in a wheat-chickpea rotation and the potential positive impact of a cover crop in a sub-tropical climate (QLD, Australia) on SOC. It also showed the complexities in managing to achieve increased SOC, while simultaneously aiming to minimize nitrous oxide (N2O) emissions and nitrate leaching in farming systems. The transposition of contrasting soils and climates in

  2. Understanding the Impacts of Soil, Climate, and Farming Practices on Soil Organic Carbon Sequestration: A Simulation Study in Australia

    PubMed Central

    Godde, Cécile M.; Thorburn, Peter J.; Biggs, Jody S.; Meier, Elizabeth A.

    2016-01-01

    Carbon sequestration in agricultural soils has the capacity to mitigate greenhouse gas emissions, as well as to improve soil biological, physical, and chemical properties. The review of literature pertaining to soil organic carbon (SOC) dynamics within Australian grain farming systems does not enable us to conclude on the best farming practices to increase or maintain SOC for a specific combination of soil and climate. This study aimed to further explore the complex interactions of soil, climate, and farming practices on SOC. We undertook a modeling study with the Agricultural Production Systems sIMulator modeling framework, by combining contrasting Australian soils, climates, and farming practices (crop rotations, and management within rotations, such as fertilization, tillage, and residue management) in a factorial design. This design resulted in the transposition of contrasting soils and climates in our simulations, giving soil–climate combinations that do not occur in the study area to help provide insights into the importance of the climate constraints on SOC. We statistically analyzed the model’s outputs to determinate the relative contributions of soil parameters, climate, and farming practices on SOC. The initial SOC content had the largest impact on the value of SOC, followed by the climate and the fertilization practices. These factors explained 66, 18, and 15% of SOC variations, respectively, after 80 years of constant farming practices in the simulation. Tillage and stubble management had the lowest impacts on SOC. This study highlighted the possible negative impact on SOC of a chickpea phase in a wheat–chickpea rotation and the potential positive impact of a cover crop in a sub-tropical climate (QLD, Australia) on SOC. It also showed the complexities in managing to achieve increased SOC, while simultaneously aiming to minimize nitrous oxide (N2O) emissions and nitrate leaching in farming systems. The transposition of contrasting soils and

  3. Development of an advanced actuator disk model for Large-Eddy Simulation of wind farms

    NASA Astrophysics Data System (ADS)

    Moens, Maud; Duponcheel, Matthieu; Winckelmans, Gregoire; Chatelain, Philippe

    2015-11-01

    This work aims at improving the fidelity of the wind turbine modelling for Large-Eddy Simulation (LES) of wind farms, in order to accurately predict the loads, the production, and the wake dynamics. In those simulations, the wind turbines are accounted for through actuator disks. i.e. a body-force term acting over the regularised disk swept by the rotor. These forces are computed using the Blade Element theory to estimate the normal and tangential components (based on the local simulated flow and the blade characteristics). The local velocities are modified using the Glauert tip-loss factor in order to account for the finite number of blades; the computation of this correction is here improved thanks to a local estimation of the effective upstream velocity at every point of the disk. These advanced actuator disks are implemented in a 4th order finite difference LES solver and are compared to a classical Blade Element Momentum method and to high fidelity wake simulations performed using a Vortex Particle-Mesh method in uniform and turbulent flows.

  4. Investigations and mathematical simulation on decentralized anaerobic treatment of agricultural substrate from livestock farming.

    PubMed

    Wichern, M; Lübken, M; Horn, H; Schlattmann, M; Gronauer, A

    2008-01-01

    Anaerobic processes are widely used for treatment of both municipal and industrial wastewater as well as agricultural substrates. In contrast to the aerobic methods, they are frequently more cost-efficient, they have a lower surplus sludge production, and the reactors can be run with higher volumetric loads and thus smaller volumes. In the paper presented both experimental data and the application of the Anaerobic Digestion Model No. 1 for agricultural substrate from livestock farming will be described. A 3,500 L reactor with mesophilic operation and loaded with cattle manure was examined with respect to its COD degradation, gas production, and gas composition. Results revealed a reduction of 30-35% COD and a biogas production of 287 L(Biogas)/kg(VS) when operated with a specific loading rate of 3.6 kg(VS)/(m(3).d).After calibration of the ADM 1, which was based predominantly on the acetate uptake rate (k(ac.m)=3.6 g/(g.d)), the disintegration constant (k(Dis)=0.05 d(-1)) and the exact determination of the influent COD fractions contained in the agricultural substrate, it was possible to simulate the measured data of the plant in excellent quality. For future application of the ADM 1 as part of control strategies a sensitivity analysis was carried out. The analysis based on the SVM slope technique has been done to identify highly sensitive biochemical parameters. These are, amongst others, the acetate uptake rate, the disintegration constant, the biomass decay rates and the half saturation constant for ammonia inhibition. Sensitivity analysis of the inflow COD fractions (proteins, carbohydrates, lipids and inert) showed the necessity of detailed measurements for the prediction of the gas flow and composition as well as for prognosis of inhibitions in the anaerobic process. For cattle manure especially the fractions of inert material and carbohydrates should be observed carefully. Due to the high content of NH(4)-N in manure the protein fraction is not as sensitive

  5. Presenting simulation results in a nested loop plot.

    PubMed

    Rücker, Gerta; Schwarzer, Guido

    2014-12-12

    Statisticians investigate new methods in simulations to evaluate their properties for future real data applications. Results are often presented in a number of figures, e.g., Trellis plots. We had conducted a simulation study on six statistical methods for estimating the treatment effect in binary outcome meta-analyses, where selection bias (e.g., publication bias) was suspected because of apparent funnel plot asymmetry. We varied five simulation parameters: true treatment effect, extent of selection, event proportion in control group, heterogeneity parameter, and number of studies in meta-analysis. In combination, this yielded a total number of 768 scenarios. To present all results using Trellis plots, 12 figures were needed. Choosing bias as criterion of interest, we present a 'nested loop plot', a diagram type that aims to have all simulation results in one plot. The idea was to bring all scenarios into a lexicographical order and arrange them consecutively on the horizontal axis of a plot, whereas the treatment effect estimate is presented on the vertical axis. The plot illustrates how parameters simultaneously influenced the estimate. It can be combined with a Trellis plot in a so-called hybrid plot. Nested loop plots may also be applied to other criteria such as the variance of estimation. The nested loop plot, similar to a time series graph, summarizes all information about the results of a simulation study with respect to a chosen criterion in one picture and provides a suitable alternative or an addition to Trellis plots.

  6. EVALUATION OF AP-FARM SIMULANT COMPOSITION FOR ROTARY MICROFILTER TESTING

    SciTech Connect

    HUBER HJ

    2011-09-19

    This document identifies the feed composition of a Hanford AP tank farm simulant for rotary microfiltration testing. The composition is based on an Hanford Tank Waste Operations Simulator (HTWOS) model run in combination with Tank Waste Information Network (TWINS) data and mineralogical studies of actual waste solids. The feed simulant is intended to be used in test runs at SRNL. The simulant will be prepared in two parts: (1) A supernate, composed of water-soluble salts and (2) The undissolved (actually, undissolvable) solids. Test slurries with distinct solids concentrations (e.g., 0.5, 5 and 10 wt%) are then prepared as needed. The base for the composition of supernate and solids is the modeled feed sequence for a deployment scenario of the Supplemental Pretreatment units within AP-farm. These units comprise a filtration part, the RMF, and a Cesium-removal part, a Small Column Ion Exchange. The primary use of this simulant is for filtration testing - however, in case that it is also used for ion-exchange tests, the amount of Cs-137 that would need to be added is available in Table 1 and Attachment 3. A modified model run (MMR-049) of the Hanford Tank Waste Operations Simulator (HTWOS) system plan 6 case 3 was performed to identify the feed sequence. Case 3 assumed supplemental treatment besides the low activity waste (LAW) melter with supplemental pretreatment supporting the pretreatment facility. The MMR did not cap the duration of supplemental pretreatment to 15 months, but rather used it throughout the entire treatment mission as an add-on option to the pretreatment facility at the Waste Treatment and Immobilization Plant (WTP). Tank 241-AP-105 (AP-105) was chosen as the feed tank to the filtration unit. Other parameters included a fixed minimum of 0.5 wt% solids in the feed and a maximum Na-concentration of 5M in the supernate. The solids rejection from the filtration unit was set to 99.99% and the maximum allowed amount of solids within tank AP-105 was set

  7. 2005 Closure Assessments for WMA-C Tank Farms: Numerical Simulations

    SciTech Connect

    Freedman, Vicky L; Zhang, Z F; Waichler, Scott R; Wurstner, Signe K

    2005-09-20

    In support of CH2M HILL Hanford Group, Inc.'s (CHG) closure of the Hanford Site Single-Shell Tank (SST) Waste Management Area (WMA) tank farms, numerical simulations of flow and solute transport were executed to investigate different potential contaminant source scenarios that may pose long-term risks to groundwater from the closure of the C Tank Farm. These simulations were based on the initial assessment effort (Zhang et al., 2003), but implemented a revised approach that examined a range of key parameters and multiple base cases. Four different potential source types were identified to represent the four base cases, and included past leaks, diffusion releases from residual wastes, leaks during retrieval, and ancillary equipment sources. Using a two-dimensional cross section through the C Tank Farm (Tanks C-103–C-112) and a unit release from Tank C-112, two solutes (uranium-238 (U-238) and technetium-99 (Tc 99)) were transported through the problem domain. To evaluate the effect of sorption on contaminant transport, seven different sorption coefficients were simulated for U 238. Apart from differences in source releases, all four base cases utilized the same median parameter values to describe flow and contaminant transport at the WMA C. Forty-six additional cases were also run that examined individual transport responses to the upper and lower limits of the median parameter values implemented in the base case systems. For the conservative solute, Tc-99, results amongst the base cases showed that the simulations investigating past leaks demonstrated the highest peak concentrations and the earliest arrival times (48 years) due to the proximity of the plume to the water table and the high recharge rate before surface barriers were installed. Simulations investigating leaks during retrieval predicted peak concentrations ~60 times smaller than the past leak cases, and corresponding arrival times that occurred ~70 years later. The diffusion release base case

  8. "A New Life in the Countryside Awaits": Interactive Lessons in the Rural Utopia in "Farming" Simulation Games

    ERIC Educational Resources Information Center

    Cole, Matthew; Stewart, Kate

    2017-01-01

    This paper critically analyses the legitimation of exploitative human-nonhuman animal relations in online "farming" simulation games, especially the game Hay Day. The analysis contributes to a wider project of critical analyses of popular culture representations of nonhuman animals. The paper argues that legitimation is effected in Hay…

  9. Stochastic Parameter Development for PORFLOW Simulations of the Hanford AX Tank Farm

    SciTech Connect

    Ho, C.K.; Baca, R.G.; Conrad, S.H.; Smith, G.A.; Shyr, L.; Wheeler, T.A.

    1999-01-01

    Parameters have been identified that can be modeled stochastically using PORFLOW and Latin Hypercube Sampling (LHS). These parameters include hydrologic and transport properties in the vadose and saturated zones, as well as source-term parameters and infiltration rates. A number of resources were used to define the parameter distributions, primarily those provided in the Retrieval Performance Evaluation Report (Jacobs, 1998). A linear rank regression was performed on the vadose-zone hydrologic parameters given in Khaleel and Freeman (1995) to determine if correlations existed between pairs of parameters. No strong correlations were found among the vadose-zone hydrologic parameters, and it was recommended that these parameters be sampled independently until future data or analyses reveal a strong correlation or functional relationship between parameters. Other distributions for source-term parameters, infiltration rates, and saturated-zone parameters that are required to stochastically analyze the performance of the AX Tank Farm using LHS/PORFLOW were adapted from distributions and values reported in Jacobs (1998) and other literature sources. Discussions pertaining to the geologic conceptualization, vadose-zone modeling, and saturated-zone modeling of the AX Tank Farm are also presented.

  10. Mechanisms of gas generation from simulated SY tank farm wastes: FY 1995 progress report

    SciTech Connect

    Barefield, E.K.; Boatright, D.; Deshpande, A.; Doctorovich, F.; Liotta, C.L.; Neumann, H.M.; Seymore, S.

    1996-07-01

    The objective of this work is to develop a better understanding of the mechanism of formation of flammable gases in the thermal decomposition of metal complexants such as HEDTA and sodium glycolate in simulated SY tank farm waste mixtures. This report summarizes the results of work done at the Georgia Institute of Technology in fiscal year 1995. Topics discussed are (1) long-term studies of the decomposition of HEDTA in simulated waste mixtures under an argon atmosphere at 90 and 120{degrees}C, including time profiles for disappearance of HEDTA and appearance of products and the quantitative analysis of the kinetic behavior; (2) considerations of hydroxylamine as an intermediate in the production of nitrogen containing gases by HEDTA decomposition; (3) some thoughts on the revision of the global mechanism for thermal decomposition of HEDTA under argon; (4) preliminary long-term studies of the decomposition of HEDTA in simulated waste under an oxygen atmosphere at 120{degrees}C; (5) estimation of the amount of NH{sub 3} in the gas phase above HEDTA reaction mixtures; and (6) further, examination of the interaction of aluminum with nitrite ion using {sup 27}Al NMR spectroscopy. Section 2 of this report describes the work conducted over the last three years at GIT. Section 3 contains a discussion of the kinetic behavior of HEDTA under argon; Section 4 discusses the role of hydroxylamine. Thermal decomposition of HEDTA to ED3A is the subject of Section 5, and decomposition of HEDTA in simulated waste mixtures under oxygen is covered in Section 6. In Section 7 we estimate ammonia in the gas phase; the role of aluminum is discussed in Section 8.

  11. The master student presenter: Peer teaching in the simulation laboratory.

    PubMed

    Kurtz, Christine P; Lemley, Constance S; Alverson, Elise M

    2010-01-01

    The professional nurse needs to be able demonstrate the roles of teacher, manager, lifelong learner, research consumer, and provider of care. A teaching strategy that fosters the integration of these roles by the student is the Master Student Presenter (MSP) assignment, whereby students teach peers a fundamental skill in the simulation laboratory setting. The objectives of this assignment are for students to: (a) synthesize current literature to establish an evidence-based practice, (b) deliver an oral presentation, (c) demonstrate a skill to fellow students, and (d) evaluate peers on skill performance. Using the MSP assignment in the simulation laboratory contributes to the process of integrating these roles, which students build upon throughout their nursing education.

  12. Modelling growth variability in longline mussel farms as a function of stocking density and farm design

    NASA Astrophysics Data System (ADS)

    Rosland, Rune; Bacher, Cédric; Strand, Øivind; Aure, Jan; Strohmeier, Tore

    2011-11-01

    Mussels ( Mytilus edulis) are commonly cultivated on artificial structures like rafts, poles or longlines to facilitate farming operations. Farm structures and dense mussel populations may result in water flow reduction and seston depletion and thus reduced individual mussel growth and spatial growth variability inside a farm. One of the challenges in mussel farming is thus to scale and configure farms in order to optimise total mussel production and individual mussel quality under different environmental regimes. Here we present a spatially resolved model for simulation of flow reduction, seston depletion and individual mussel growth inside a longline farm based on information about farm configuration (spacing between longlines, farm length and stocking density) and background environmental conditions (current speed, seston concentration and temperature). The model simulations are forced by environmental data from two fjords in south-western Norway and the farm configurations are defined within operational ranges. The simulations demonstrate spatial growth patterns at longlines under environmental settings and farm configurations where flow reduction and seston depletion have significant impacts on individual mussel growth. Longline spacing has a strong impact on the spatial distribution of individual growth, and the spacing is characterised by a threshold value. Below the threshold growth reduction and spatial growth variability increase rapidly as a consequence of reduced water flow and seston supply rate, but increased filtration due to higher mussel densities also contributes to the growth reduction. The spacing threshold is moderated by other farm configuration factors and environmental conditions. Comparisons with seston depletion reported from other farm sites show that the model simulations are within observed ranges. A demonstration is provided on how the model can guide farm configuration with the aim of optimising total farm biomass and individual

  13. A Descriptive Study of Farm-Related Injuries Presenting to Emergency Departments in North Carolina: 2008-2012.

    PubMed

    Allen, Daniel Landon; Kearney, Gregory D; Higgins, Sheila

    2015-01-01

    Farming is among the most dangerous industries for fatal and nonfatal injuries. A comprehensive agricultural injury surveillance system is absent in North Carolina (NC), and data sets traditionally used to provide estimates of nonfatal farm injuries surveillance in the United States are relatively incomplete. In the absence of a comprehensive farm injury surveillance system, individual local administrative data sources can provide a useful profile of the epidemiology of injuries in a population. The objective of this study was to use emergency department data to help describe the burden of farm-related injuries in NC and explore its usefulness in conducting work-related injury surveillance. Emergency department data from the North Carolina Disease Event Tracking and Epidemiologic Collection Tool (NC DETECT) was utilized to identify farm injury cases. The study sample included all farm injury cases for the period of 2008-2012 that contained International Classification of Diseases, Ninth Revision, Clinical Modification (ICD-9-CM) E code 919.0 (agricultural machinery) or 849.1 (place of occurrence = farm; this E code excludes farm house and home premises of farm). Results indicated that an average of 459 cases of farm injury occurred annually from 2008 to 2012, with no significant change between years. Among the patients, 79.7% were male, 74.7% were between 18 and 64 years old, and 28.1% had no form of insurance coverage. Injuries were more heavily concentrated in the Piedmont and Coastal Plains regions (41.3% and 42.2%, respectively). Of farm-coded incidents, 73.2% were given injury- or poisoning-related primary diagnosis codes, and of these, the most frequent specific codes were related to open wounds of upper limbs (16.2%), contusions (12.0%), and sprains and strains (9.3%). Some significant relationships between diagnoses and sex, region, and age are also identified. Injuries occurring on a farm have been well documented and constitute a significant public health

  14. Report on the Oak Ridge sewage sludge land-farming experience. Part 1. Data presentation

    SciTech Connect

    Oakes, T.W.; Braunstein, H.M.; Daniels, K.L.; Ohnesorge, W.F.; Kitchings, J.T.; Alexander, W.A.

    1984-08-01

    Disposal of sludge from the City of Oak Ridge's sewage treatment facility on a 65-acre site on the Department of Energy's Oak Ridge Reservation was initiated in November 1983. On March 22, 1984, DOE and the City determined that the sludge contained radioactive materials. Application of sludge on the Reservation was suspended on March 25 and a comprehensive survey and sampling plan was instituted to radiologically characterize the disposal site. By April 1, a radiation walkover survey had been completed on the site and samples of air, water, and soil had been collected to be analyzed for the presence of radionuclides. The mean air dose rate, one meter above the ground surface, was found to be 13 ..mu..R/h with a range from about 8 ..mu..R/h, which is the usual background level in the area, to 21 ..mu..R/h. Concentrations of Cs-137 and Co-60, the principle contaminants in the soil, were essentially below the analytical detection limits in the air and water. About 350 soil samples were collected by extracting cores to a depth of 12 to 15 inches according to a systematic random sampling design. Each core was separated into three sections; the top 3 inches, a middle section, and the bottom 3 inches to represent layers on the site. The majority of the radioactivity was determined to be in the upper 3 inches of soil. A statistical treatment of the analytical results provided an estimate of the total activity at the site, the vertical distribution of the gamma activity, and the areal distribution of the primary radionuclides. A total of 170 mCi of activity was estimated as present in the top 3-inch layer of the 65-acre site, 69% of which was contributed by Co-60 and Cs-137, 23% by U-234 and Sr-90, and 8% by other minor radionuclides. 4 references, 12 figures, 43 tables.

  15. Biological exhaust air treatment systems as a potential microbial risk for farm animals assessed with a computer simulation.

    PubMed

    Seedorf, Jens

    2013-09-01

    Livestock operations are under increasing pressure to fulfil minimum environmental requirements and avoid polluting the atmosphere. In regions with high farm animal densities, new farm buildings receive building permission only when biological exhaust air treatment systems (BEATS) are in place, such as biofilters. However, it is currently unknown whether BEATS can harbour pathogens such as zoonotic agents, which are potentially emitted via the purified gas. Because BEATS are located very close to the livestock building, it is assumed that BEATS-related microorganisms are aerially transported to farm animals via the inlet system of the ventilation system. To support this hypothesis, a computer simulation was applied to calculate the wind field around a facility consisting of a virtual livestock house and an adjacent biofilter. Under the chosen wind conditions (speed and direction), it can be shown that turbulences and eddies may occur in the near surrounding of a livestock building with an adjacent biofilter. Consequently, this might cause the entry of the released biofilter's purified gas into the barn, including possible microorganisms within this purified gas. If field investigations verify the results of the simulations, counter-measures must be taken to ensure biosecurity on farms with BEATS. © 2013 Society of Chemical Industry.

  16. SIMULATION OF CARBON DIOXIDE EMISSIONS FROM DAIRY FARMS TO ASSESS GREENHOUSE GAS REDUCTION STRATEGIES

    USDA-ARS?s Scientific Manuscript database

    Farming practices can have a large impact on the soil carbon cycle and the resulting net emission of greenhouse gases including carbon dioxide (CO**2), methane and nitrous oxide. Primary sources of CO**2 emission on dairy farms are soil, plant, and animal respiration with smaller contributions from ...

  17. SIMULATION OF NITROUS OXIDE EMISSIONS FROM DAIRY FARMS TO ASSESS GREENHOUSE GAS REDUCTION STRATEGIES

    USDA-ARS?s Scientific Manuscript database

    Farming practices can have a large impact on the net emission of greenhouse gases including carbon dioxide, methane, and nitrous oxide (N**2O). The primary sources of N**2O from dairy farms are nitrification and denitrification processes in soil, with smaller contributions from manure storage and ba...

  18. Pituitary apoplexy presenting as diabetic ketoacidosis: A great simulator?

    PubMed

    Camara-Lemarroy, Carlos R; Infante-Valenzuela, Adrian; Rodriguez-Velver, Karla; Rodriguez-Gutierrez, Rene; Villareal-Velazquez, Hector J

    2016-01-01

    Pituitary apoplexy is a life-threatening illness due to acute infarction of the pituitary gland. The most common symptoms associated with pituitary apoplexy are headache, nausea, vomiting, visual impairment, hypopituitarism, and altered mental status. Diabetic ketoacidosis is a common acute complication of diabetes mellitus and is itself associated with similar symptoms. We present the case of a 38 year old woman, who presented with altered mental status and biochemical alterations suggestive of diabetic ketoacidosis who was found to have a pituitary apoplexy. The low frequency of this condition coupled with an acute and usually dramatic presentation that includes non-specific symptoms makes it a diagnostic challenge. Pituitary apoplexy can simulate a wide range of neurological conditions.

  19. Factitious Disorder Presenting with Attempted Simulation of Fournier's Gangrene.

    PubMed

    Tseng, Joseph; Poullos, Peter

    2016-09-01

    Fournier's gangrene is a severe polymicrobial necrotizing fasciitis of the perineal, genital, or perianal regions. The classic presentation is severe pain and swelling with systemic signs. Crepitus and cutaneous necrosis are often seen. Characteristic CT findings include subcutaneous gas and inflammatory stranding. Unless treated aggressively, patients can rapidly become septic and die. Factitious Disorder is the falsification of one's own of medical or psychological signs and symptoms. Many deceptive methods have been described, from falsely reporting physical or psychological symptoms, to manipulating lab tests, or even injecting or ingesting foreign substances in order to induce illness. We present a case of a 35-year-old man with factitious disorder who attempted to simulate Fournier's gangrene by injecting his scrotum with air and fluid. We will review the clinical presentation and diagnosis of Factitious Disorder, as well as Fournier's gangrene.

  20. Simulation of Long-Term Carbon and Nitrogen Dynamics in Grassland-Based Dairy Farming Systems to Evaluate Mitigation Strategies for Nutrient Losses

    PubMed Central

    Shah, Ghulam Abbas; Groot, Jeroen C.J.; Shah, Ghulam Mustafa; Lantinga, Egbert A.

    2013-01-01

    Many measures have been proposed to mitigate gaseous emissions and other nutrient losses from agroecosystems, which can have large detrimental effects for the quality of soils, water and air, and contribute to eutrophication and global warming. Due to complexities in farm management, biological interactions and emission measurements, most experiments focus on analysis of short-term effects of isolated mitigation practices. Here we present a model that allows simulating long-term effects at the whole-farm level of combined measures related to grassland management, animal housing and manure handling after excretion, during storage and after field application. The model describes the dynamics of pools of organic carbon and nitrogen (N), and of inorganic N, as affected by farm management in grassland-based dairy systems. We assessed the long-term effects of delayed grass mowing, housing type (cubicle and sloping floor barns, resulting in production of slurry and solid cattle manure, respectively), manure additives, contrasting manure storage methods and irrigation after application of covered manure. Simulations demonstrated that individually applied practices often result in compensatory loss pathways. For instance, methods to reduce ammonia emissions during storage like roofing or covering of manure led to larger losses through ammonia volatilization, nitrate leaching or denitrification after application, unless extra measures like irrigation were used. A strategy of combined management practices of delayed mowing and fertilization with solid cattle manure that is treated with zeolite, stored under an impermeable sheet and irrigated after application was effective to increase soil carbon stocks, increase feed self-sufficiency and reduce losses by ammonia volatilization and soil N losses. Although long-term datasets (>25 years) of farm nutrient dynamics and loss flows are not available to validate the model, the model is firmly based on knowledge of processes and

  1. Simulation of Long-Term Carbon and Nitrogen Dynamics in Grassland-Based Dairy Farming Systems to Evaluate Mitigation Strategies for Nutrient Losses.

    PubMed

    Shah, Ghulam Abbas; Groot, Jeroen C J; Shah, Ghulam Mustafa; Lantinga, Egbert A

    2013-01-01

    Many measures have been proposed to mitigate gaseous emissions and other nutrient losses from agroecosystems, which can have large detrimental effects for the quality of soils, water and air, and contribute to eutrophication and global warming. Due to complexities in farm management, biological interactions and emission measurements, most experiments focus on analysis of short-term effects of isolated mitigation practices. Here we present a model that allows simulating long-term effects at the whole-farm level of combined measures related to grassland management, animal housing and manure handling after excretion, during storage and after field application. The model describes the dynamics of pools of organic carbon and nitrogen (N), and of inorganic N, as affected by farm management in grassland-based dairy systems. We assessed the long-term effects of delayed grass mowing, housing type (cubicle and sloping floor barns, resulting in production of slurry and solid cattle manure, respectively), manure additives, contrasting manure storage methods and irrigation after application of covered manure. Simulations demonstrated that individually applied practices often result in compensatory loss pathways. For instance, methods to reduce ammonia emissions during storage like roofing or covering of manure led to larger losses through ammonia volatilization, nitrate leaching or denitrification after application, unless extra measures like irrigation were used. A strategy of combined management practices of delayed mowing and fertilization with solid cattle manure that is treated with zeolite, stored under an impermeable sheet and irrigated after application was effective to increase soil carbon stocks, increase feed self-sufficiency and reduce losses by ammonia volatilization and soil N losses. Although long-term datasets (>25 years) of farm nutrient dynamics and loss flows are not available to validate the model, the model is firmly based on knowledge of processes and

  2. Simulation of between-farm transmission of porcine reproductive and respiratory syndrome virus in Ontario, Canada using the North American Animal Disease Spread Model.

    PubMed

    Thakur, Krishna K; Revie, Crawford W; Hurnik, Daniel; Poljak, Zvonimir; Sanchez, Javier

    2015-03-01

    Porcine reproductive and respiratory syndrome (PRRS), a viral disease of swine, has major economic impacts on the swine industry. The North American Animal Disease Spread Model (NAADSM) is a spatial, stochastic, farm level state-transition modeling framework originally developed to simulate highly contagious and foreign livestock diseases. The objectives of this study were to develop a model to simulate between-farm spread of a homologous strain of PRRS virus in Ontario swine farms via direct (animal movement) and indirect (sharing of trucks between farms) contacts using the NAADSM and to compare the patterns and extent of outbreak under different simulated conditions. A total of 2552 swine farms in Ontario province were allocated to each census division of Ontario and geo-locations of the farms were randomly generated within the agriculture land of each Census Division. Contact rates among different production types were obtained using pig movement information from four regions in Canada. A total of 24 scenarios were developed involving various direct (movement of infected animals) and indirect (pig transportation trucks) contact parameters in combination with alternating the production type of the farm in which the infection was seeded. Outbreaks were simulated for one year with 1000 replications. The median number of farms infected, proportion of farms with multiple outbreaks and time to reach the peak epidemic were used to compare the size, progression and extent of outbreaks. Scenarios involving spread only by direct contact between farms resulted in outbreaks where the median percentage of infected farms ranged from 31.5 to 37% of all farms. In scenarios with both direct and indirect contact, the median percentage of infected farms increased to a range from 41.6 to 48.6%. Furthermore, scenarios with both direct and indirect contact resulted in a 44% increase in median epidemic size when compared to the direct contact scenarios. Incorporation of both animal

  3. Publication of Abstracts Presented at an International Healthcare Simulation Conference.

    PubMed

    Cheng, Adam; Lin, Yiqun; Smith, Jeremy; Wan, Brandi; Belanger, Claudia; Hui, Joshua

    2017-08-01

    We aimed to determine the publication rate for abstracts presented at the International Meeting for Simulation in Healthcare (IMSH) and the time between abstract presentation and publication. We also aimed to describe the study features influencing subsequent publication and the relationship between these features and journal impact factors (IFs). All types of accepted abstracts from the 2012 and 2013 IMSH were reviewed. We extracted the following data from each abstract in duplicate: presentation format, subject, type of scholarship, research method, study design, outcome measure, number of institutions in authorship group, and number of study sites. PubMed and Google Scholar were searched (January 1, 2012 to August 1, 2016) using the names of the first, second, and last author for comparison with abstracts. Journal of publication and IF were recorded. Data were summarized with descriptive statistics. Bivariate and multivariate analysis was performed to explore the association between publication status and other variables. Of 541 abstracts, 22% (119/541) were published with a median time to publication of 16 months (interquartile range = 8.525), ranging from 0 to 43 months. The study characteristics associated with a greater likelihood of publication were the following: research-type abstract, quantitative studies, randomized trials, studies with patient or healthcare-related outcomes, multiple institutions represented in authorship group, and multicenter studies. Studies with multiple institutions in authorship group and multicenter studies were published in higher IF journals (P < 0.05). The publication rate of 22% for abstracts presented at IMSH is low, indicative of the relatively new nature of simulation-based research in healthcare.

  4. Application of a large-eddy simulation model to the analysis of flow conditions in offshore wind farms

    NASA Astrophysics Data System (ADS)

    Steinfeld, Gerald; Tambke, Jens; Peinke, Joachim; Heinemann, Detlev

    2010-05-01

    obtained at the offshore test site by data that is obtained from large-eddy simulations (LES) using the LES model PALM with actuator disk and actuator line approaches. The LES approach that shall be validated against the results of the measurements allows us to obtain flow data with a spatial and temporal resolution that cannot be reached in field experiments. Moreover, comprehensive parameter studies can easily be carried out with the LES model just by changing its initial and boundary conditions, such as thermal stratification or large-scale pressure gradient. PALM allows the application of turbulent inflow as well as cyclic lateral boundary conditions. Thus, it can be used to study the flow behind a single wind turbine, the flow within and behind a wind farm that has a limited horizontal extension as well as the flow within a wind farm of unlimited extension. Carrying out the simulations on the HLRN (North German Alliance for Supercomputing) supercomputer with about 25000 CPUs allows us to use a very high resolution of 1 m, while the horizontal extension of the model domain reaches several square kilometres. Thus, PALM seems to be a promising tool to study the turbulent flow in offshore wind farms with their giant numbers and dimensions of wind turbines. The goal of this conference contribution is to point out the great potential of the LES method for the systematic analysis of wind turbine and wind farm wake flows. Results of the wake flow behind a single wind turbine validated with prior numerical results and measurements as well as behind a scale model of the "alpha ventus" test site will be shown.

  5. Proper orthogonal decomposition of a large eddy simulation during a diurnal cycle for very large wind farms

    NASA Astrophysics Data System (ADS)

    Ali, Naseem; Cortina, Gerard; Hamilton, Nicholas; Calaf, Marc; Cal, Raúl

    2016-11-01

    The structure of the turbulent flow within large wind farms under different atmospheric flow stratification (stable, unstable and neutral) and compares it to the case when there are no turbines present. Spectral analysis is further applied to the corresponding proper orthogonal modes to identify the characteristic wavenumber and be able to relate it to the actual wind farm structure and wake-to-wake interactions. The variation in the number of needed modes between the different cases decreases with increasing value of cumulative energy, which confirms that the major difference between the different study cases resides at the largest turbulent kinetic energy containing scales of each case. The POD modes show the stratification impact of the flow structure and distinguish the flow layers. The spectral analysis displays the domain size and the distance between the rotors as distinctive scales within the wind farm.

  6. Large-Eddy Simulation of Atmospheric Boundary-Layer Flow Through a Wind Farm Sited on Topography

    NASA Astrophysics Data System (ADS)

    Shamsoddin, Sina; Porté-Agel, Fernando

    2016-11-01

    Large-eddy simulation (LES) has recently been well validated and applied in the context of wind turbines over flat terrain; however, to date its accuracy has not been tested systematically in the case of turbine-wake flows over topography. Here, we investigate the wake flow in a wind farm situated on hilly terrain using LES for a case where wind-tunnel experimental data are available. To this end, first boundary-layer flow is simulated over a two-dimensional hill in order to characterize the spatial distribution of the mean velocity and the turbulence statistics. A flow simulation is then performed through a wind farm consisting of five horizontal-axis wind turbines sited over the same hill in an aligned layout. The resulting flow characteristics are compared with the former case, i.e., without wind turbines. To assess the validity of the simulations, the results are compared with the wind-tunnel measurements. It is found that LES can reproduce the flow field effectively, and, specifically, the speed-up over the hilltop and the velocity deficit and turbulence intensity enhancement induced by the turbines are well captured by the simulations. Besides, the vertical profiles of the mean velocity and turbulence intensity at different streamwise positions match well those for the experiment. In addition, another numerical experiment is carried out to show how higher (and more realistic) thrust coefficients of the turbines lead to stronger wakes and, at the same time, higher turbulence intensities.

  7. Large-Eddy Simulation of Atmospheric Boundary-Layer Flow Through a Wind Farm Sited on Topography

    NASA Astrophysics Data System (ADS)

    Shamsoddin, Sina; Porté-Agel, Fernando

    2017-04-01

    Large-eddy simulation (LES) has recently been well validated and applied in the context of wind turbines over flat terrain; however, to date its accuracy has not been tested systematically in the case of turbine-wake flows over topography. Here, we investigate the wake flow in a wind farm situated on hilly terrain using LES for a case where wind-tunnel experimental data are available. To this end, first boundary-layer flow is simulated over a two-dimensional hill in order to characterize the spatial distribution of the mean velocity and the turbulence statistics. A flow simulation is then performed through a wind farm consisting of five horizontal-axis wind turbines sited over the same hill in an aligned layout. The resulting flow characteristics are compared with the former case, i.e., without wind turbines. To assess the validity of the simulations, the results are compared with the wind-tunnel measurements. It is found that LES can reproduce the flow field effectively, and, specifically, the speed-up over the hilltop and the velocity deficit and turbulence intensity enhancement induced by the turbines are well captured by the simulations. Besides, the vertical profiles of the mean velocity and turbulence intensity at different streamwise positions match well those for the experiment. In addition, another numerical experiment is carried out to show how higher (and more realistic) thrust coefficients of the turbines lead to stronger wakes and, at the same time, higher turbulence intensities.

  8. Large-eddy simulation of the diurnal variation of wake flows in a finite-size wind farm

    NASA Astrophysics Data System (ADS)

    Abkar, Mahdi; Sharifi, Ahmad; Porté-Agel, Fernando

    2015-06-01

    In this study, large-eddy simulation (LES) is used to study the evolution of the wind-turbine wakes and their effects on power losses inside an idealized finite-size wind farm in the course of a full diurnal cycle. In the LES, turbulent subgrid-scale stresses are modeled using tuning-free Lagrangian scale-dependent dynamic models, while the turbine-induced forces are parameterized using a dynamic actuator disk model with rotation. The simulation results show a strong effect of atmospheric stability on the wind farm wakes and associated power losses. During the night, the relatively low turbulence intensity of the ambient ABL flow results in a relatively slow rate of entrainment of momentum into the wake and, consequently, a slow wake recovery. In contrast, during the day the positive buoyancy flux and associated turbulence production lead to a relatively high turbulence level in the background ABL flow, which enhances turbulent mixing and wake recovery. As a result, the averaged power deficit in the wind farm is found to increase with increasing thermal stability. In particular for that day, the averaged power deficit increased from 28% under the most convective condition to about 57% under the most stable condition.

  9. Optimizing farm landscape by two decision-support tools for present and future: A case study in a mountainous farm of Taiwan

    NASA Astrophysics Data System (ADS)

    Chou, S.; Lin, Y.

    2013-12-01

    Rapid expansion of agricultural land-use has been identified as the main factor degrading biodiversity. Many studies have indicated that habitat quality and connectivity for multiple species can be preserved by applying the systematic conservation planning and software programs for spatial conservation prioritizations are usually used by planners to solve conservation problems for present and future. However, each conservation software program uses different algorithms and may not be suitable or efficient for all case studies. Therefore, in this study we compared the performance of two commonly used decision-support tools, Marxan and Zonation, on identifying priority areas as reserve region for 16 bird species in the mountain area of Taiwan. The priority areas are considered as the results of the tradeoff between bird presence (biological factor) and agricultural products (economic factor). Marxan uses the minimum set approach to identify priority areas for meeting specific targets while Zonation uses the maximum coverage approach to identify priority areas given a fixed budget. Therefore, we design the scenario with the most comparable setting, which selects target-based planning as the removal rule and boundary length penalty option in zonation. The landscape composition and configuration of the simulated priority areas were further evaluated by using landscape metrics and their similarity were examined by using Spearman's rank tests. The results showed that Marxan performed more efficiently while Zonation generated the priority areas in better connectivity. As the selection of conservation programs depends on users objectives and needs for present and future, this study provides useful information on determining suitable and efficient decision-support tools for future bird conservation. Conservation maps for Zonation based on different BLP parameter. The conservation value for Zonation is based on the hierarchical solution output. (a)BLP =1000 (b)BLP =3000 (c

  10. Flow adjustment inside large finite-size wind farms approaching the infinite wind farm regime

    NASA Astrophysics Data System (ADS)

    Wu, Ka Ling; Porté-Agel, Fernando

    2017-04-01

    Due to the increasing number and the growing size of wind farms, the distance among them continues to decrease. Thus, it is necessary to understand how these large finite-size wind farms and their wakes could interfere the atmospheric boundary layer (ABL) dynamics and adjacent wind farms. Fully-developed flow inside wind farms has been extensively studied through numerical simulations of infinite wind farms. The transportation of momentum and energy is only vertical and the advection of them is neglected in these infinite wind farms. However, less attention has been paid to examine the length of wind farms required to reach such asymptotic regime and the ABL dynamics in the leading and trailing edges of the large finite-size wind farms. Large eddy simulations are performed in this study to investigate the flow adjustment inside large finite-size wind farms in conventionally-neutral boundary layer with the effect of Coriolis force and free-atmosphere stratification from 1 to 5 K/km. For the large finite-size wind farms considered in the present work, when the potential temperature lapse rate is 5 K/km, the wind farms exceed the height of the ABL by two orders of magnitude for the incoming flow inside the farms to approach the fully-developed regime. An entrance fetch of approximately 40 times of the ABL height is also required for such flow adjustment. At the fully-developed flow regime of the large finite-size wind farms, the flow characteristics match those of infinite wind farms even though they have different adjustment length scales. The role of advection at the entrance and exit regions of the large finite-size wind farms is also examined. The interaction between the internal boundary layer developed above the large finite-size wind farms and the ABL under different potential temperature lapse rates are compared. It is shown that the potential temperature lapse rate plays a role in whether the flow inside the large finite-size wind farms adjusts to the fully

  11. ON-FARM PRETREATMENT TECHNOLOGIES FOR IMPROVING ENZYMATIC DIGESTIBILITY OF CELLULOSE AND HEMICELLULOSE PRESENT IN PERENNIAL GRASS

    USDA-ARS?s Scientific Manuscript database

    This research investigated the ability of on-farm pretreatments with acid, alkali, ozone, or novel enzymes to improve enzymatic degradability of cellulose and hemicelluloses in biomass at the biorefinery. Two perennial grasses, switchgrass (Panicum virgatum) and reed canarygrass (Phalaris arundinace...

  12. Serotypes of Salmonella enterica Present in the Internal Organs of Mice Caught On-farm From 1995 – 1998.

    USDA-ARS?s Scientific Manuscript database

    : Salmonella enterica is a persistent and pervasive pathogen that impacts the safety of the food supply, especially in regards to poultry and poultry products. The house mouse Mus musculus is a recognized risk factor for introduction on-farm. More information is needed about Salmonella serotypes tha...

  13. Mathematical formulation and numerical simulation of bird flu infection process within a poultry farm

    NASA Astrophysics Data System (ADS)

    Putri, Arrival Rince; Nova, Tertia Delia; Watanabe, M.

    2016-02-01

    Bird flu infection processes within a poultry farm are formulated mathematically. A spatial effect is taken into account for the virus concentration with a diffusive term. An infection process is represented in terms of a traveling wave solutions. For a small removal rate, a singular perturbation analysis lead to existence of traveling wave solutions, that correspond to progressive infection in one direction.

  14. Farm simulation can help adapt dairy production systems to climate change

    USDA-ARS?s Scientific Manuscript database

    Climate change is projected to affect many aspects of dairy production including growing season length, crop growth processes, harvest timing and losses, heat stress on cattle, nutrient emissions and losses, and ultimately farm profitability. Recent historical weather and future climate projections ...

  15. SD simulation study on degraded farmland policy on farming-pastoral area under the constrains of water resources–Taking Tongliao City of Inner Mongolia as example

    NASA Astrophysics Data System (ADS)

    Xu, D. P.; Zhao, B.; Li, T. S.; Zhu, J. W.; Yu, M. M.

    2017-08-01

    Water resources are the primary factor in restricting the sustainable development of farming-pastoral regions. To support the sustainable development of water resources, whether or not the land uses patterns of farming-pastoral areas is a reasonably important issue. This paper takes Tongliao city as example for the purpose of sustainably developing the farming-pastoral area in the north. Several scientific preductions and evaluations were conducted to study the farming-pastoral landuse pattern, which is the key problem that effects sustainable development of farming-pastoral areas. The paper then proposes that 1:7 landuse pattern is suitable for the sustainable development of farming-pastotal area. Based on the analysis of the research findings on sustainable development of farming-pastoral area, the paper established a suitability evaluation indicators system of degraded farmland policies in Tongliao city, and used an Analytical Hierarchy Process (AHP) method to determine the weight to run system dynamic (SD) model. The simulation results were then obtained on social economic ecological development in Tongliao city under different degraded farmland policies, and used the comprehensive evaluation model to optimize the results. It is concluded that stabilizing the policy of degraded farmland policy is the preferential policy in Tongliao, which provides useful theoretical research for the sustainable development of farming-pastoral area.

  16. CgWind: A high-order accurate simulation tool for wind turbines and wind farms

    SciTech Connect

    Chand, K K; Henshaw, W D; Lundquist, K A; Singer, M A

    2010-02-22

    CgWind is a high-fidelity large eddy simulation (LES) tool designed to meet the modeling needs of wind turbine and wind park engineers. This tool combines several advanced computational technologies in order to model accurately the complex and dynamic nature of wind energy applications. The composite grid approach provides high-quality structured grids for the efficient implementation of high-order accurate discretizations of the incompressible Navier-Stokes equations. Composite grids also provide a natural mechanism for modeling bodies in relative motion and complex geometry. Advanced algorithms such as matrix-free multigrid, compact discretizations and approximate factorization will allow CgWind to perform highly resolved calculations efficiently on a wide class of computing resources. Also in development are nonlinear LES subgrid-scale models required to simulate the many interacting scales present in large wind turbine applications. This paper outlines our approach, the current status of CgWind and future development plans.

  17. Non-hazardous pesticide concentrations in surface waters: An integrated approach simulating application thresholds and resulting farm income effects.

    PubMed

    Bannwarth, M A; Grovermann, C; Schreinemachers, P; Ingwersen, J; Lamers, M; Berger, T; Streck, T

    2016-01-01

    Pesticide application rates are high and increasing in upland agricultural systems in Thailand producing vegetables, fruits and ornamental crops, leading to the pollution of stream water with pesticide residues. The objective of this study was to determine the maximum per hectare application rates of two widely used pesticides that would achieve non-hazardous pesticide concentrations in the stream water and to evaluate how farm household incomes would be affected if farmers complied with these restricted application rates. For this purpose we perform an integrated modeling approach of a hydrological solute transport model (the Soil and Water Assessment Tool, SWAT) and an agent-based farm decision model (Mathematical Programming-based Multi-Agent Systems, MPMAS). SWAT was used to simulate the pesticide fate and behavior. The model was calibrated to a 77 km(2) watershed in northern Thailand. The results show that to stay under a pre-defined eco-toxicological threshold, the current average application of chlorothalonil (0.80 kg/ha) and cypermethrin (0.53 kg/ha) would have to be reduced by 80% and 99%, respectively. The income effect of such reductions was simulated using MPMAS. The results suggest that if farm households complied with the application thresholds then their income would reduce by 17.3% in the case of chlorothalonil and by 38.3% in the case of cypermethrin. Less drastic income effects can be expected if methods of integrated pest management were more widely available. The novelty of this study is to combine two models from distinctive disciplines to evaluate pesticide reduction scenarios based on real-world data from a single study site.

  18. Physical Properties Models for Simulation of Processes to Treat INEEL Tank Farm Waste: Thermodynamic Equilibrium

    SciTech Connect

    Nichols, Todd Travis; Taylor, Dean Dalton

    2002-07-01

    A status is presented of the development during FY2002 of a database for physical properties models for the simulation of the treatment of Sodium-Bearing Waste (SBW) at the Idaho National Engineering and Environmental Laboratory. An activity coefficient model is needed for concentrated, aqueous, multi-electrolyte solutions that can be used by process design practitioners. Reasonable first-order estimates of activity coefficients in the relevant media are needed rather than an incremental improvement in theoretical approaches which are not usable by practitioners. A comparison of the Electrolyte Non-Random Two-Liquid (ENRTL) and Pitzer ion-interaction models for the thermodynamic representation of SBW is presented. It is concluded that Pitzer's model is superior to ENRTL in modeling treatment processes for SBW. The applicability of the Pitzer treatment to high concentrations of pertinent species and to the determination of solubilities and chemical equilibria is addressed. Alternate values of Pitzer parameters for HCl, H2SO4, and HNO3 are proposed, applicable up to 16m, and 12m, respectively. Partial validation of the implementation of Pitzer's treatment within the commercial process simulator ASPEN Plus was performed.

  19. Physical Properties Models for Simulation of Processes to Treat INEEL Tank Farm Waste: Thermodynamic Equilibrium

    SciTech Connect

    Nichols, T.T.; Taylor, D.D.

    2002-07-18

    A status is presented of the development during FY2002 of a database for physical properties models for the simulation of the treatment of Sodium-Bearing Waste (SBW) at the Idaho National Engineering and Environmental Laboratory. An activity coefficient model is needed for concentrated, aqueous, multi-electrolyte solutions that can be used by process design practitioners. Reasonable first-order estimates of activity coefficients in the relevant media are needed rather than an incremental improvement in theoretical approaches which are not usable by practitioners. A comparison of the Electrolyte Non-Random Two-Liquid (ENRTL) and Pitzer ion-interaction models for the thermodynamic representation of SBW is presented. It is concluded that Pitzer's model is superior to ENRTL in modeling treatment processes for SBW. The applicability of the Pitzer treatment to high concentrations of pertinent species and to the determination of solubilities and chemical equilibria is addressed. Alternate values of Pitzer parameters for HCl, H2SO4, and HNO3 are proposed, applicable up to 16m, and 12m, respectively. Partial validation of the implementation of Pitzer's treatment within the commercial process simulator ASPEN Plus was performed.

  20. Assessment of weather downtime for the construction of offshore wind farm by using wind and wave simulations

    NASA Astrophysics Data System (ADS)

    Kikuchi, Yuka; Ishihara, Takeshi

    2016-09-01

    In this study, numerical simulations for winds and waves were carried out using WRF and WW3 and the predicted wind speed, wave height and wave period were validated with measurement. Annual average values of absolute monthly error of wind speed, wave height and wave period were 4.30%, 12.3% and 7.8%. The prediction accuracy were improved by bias modification in the region of low wave height and short wave period. Predicted seasonal frequency distributions showed good agreement with measurements. The criteria of experienced construction methods were investigated at Choshi and Kitakyushu wind farm and the sensitivity of environmental conditions on weather downtime were clarified. At Choshi, the weather downtime was predicted by using wind and wave simulations and showed good agreement with the actual weather downtime.

  1. Market Design Simulations with Variable Energy Resources (VERs) (Presentation)

    SciTech Connect

    Ela, E.

    2011-06-01

    Presented at the FERC Technical Conference, 29 June 2011, Washington, D.C. This presentation describes NREL research regarding variable generation resources, operating reserves, unit commitment, economic dispatch, and introduces a new and novel modeling tool called 'FESTIV.'

  2. Modeling turbine wakes and power losses within the Horns Rev offshore wind farm using large-eddy simulation

    NASA Astrophysics Data System (ADS)

    Wu, Yu-Ting; Porte-Agel, Fernando

    2013-04-01

    A recently-developed large-eddy simulations (LES) framework is implemented to predict multiple wake flows and the associated power losses within the Horns Rev offshore wind farm under near-neutral stability conditions. A tuning-free Lagrangian scale-dependent dynamic subgrid-scale (SGS) model is used for the parametrization of the SGS stresses. The turbine-generated power outputs and the turbine-induced forces (e.g., thrust, lift, drag) are parameterized using two models: (a) the traditional actuator-disk model without rotation (ADM-NR), which uses the 1D momentum theory to relate the power output and the thrust force with a representative velocity over the rotor (e.g., the disk-averaged velocity); and (b) the actuator-disk model with rotation (ADM-R), which adopts blade element theory to calculate the lift and drag forces (that produce thrust, rotor shaft torque, and power) based on the local blade and flow characteristics. In general, the predicted power outputs obtained using the ADM-R are in good agreement with observed power data from the Horns Rev wind farm. The ADM-NR tends to underestimate the power output. A similar under-prediction is obtained using industry-standard wind-farm models such as the Wind Atlas Analysis and Application Program (WAsP). Simulations using different inflow conditions show that the mean wind direction has a strong effect on the spatial distributions of the time-averaged velocity and the turbulence intensity within the farm. These, in turn, affect the power output and the fatigue loads on the turbines. When the prevailing wind direction is parallel to the turbine rows (i.e., a full wake condition), the velocity deficit and the power losses are largest, and the turbulence intensity levels are highest and have a symmetric pattern (dual-peak at hub height) on both sides of the turbine wakes. A detailed analysis of the turbulence kinetic energy budget in the full wake condition shows an important effect of the increased turbulence level

  3. A Three-Dimensional Virtual Simulator for Aircraft Flyover Presentation

    NASA Technical Reports Server (NTRS)

    Rizzi, Stephen A.; Sullivan, Brenda M.; Sandridge, Christopher A.

    2003-01-01

    This paper presents a system developed at NASA Langley Research Center to render aircraft flyovers in a virtual reality environment. The present system uses monaural recordings of actual aircraft flyover noise and presents these binaurally using head tracking information. The three-dimensional audio is simultaneously rendered with a visual presentation using a head-mounted display (HMD). The final system will use flyover noise synthesized using data from various analytical and empirical modeling systems. This will permit presentation of flyover noise from candidate low-noise flight operations to subjects for psychoacoustical evaluation.

  4. 2004 Initial Assessments for the T and TX TY Tank Farm Field Investigation Report (FIR): Numerical Simulations

    SciTech Connect

    Zhang, Z. F.; Freedman, Vicky L.; Waichler, Scott R.

    2004-09-24

    In support of CH2M HILL Hanford Group, Inc.’s (CHG) preparation of a Field Investigative Report (FIR) for the Hanford Site Single-Shell Tank Waste Management Area (WMA) T and TX-TY, a suite of numerical simulations of flow and solute transport was executed using the STOMP code to predict the performance of surface barriers for reducing long-term risks from potential groundwater contamination at the T and TX-TY WMA. The scope and parametric data for these simulations were defined by a modeling data package provided by CHG. This report documents the simulation involving 2-D cross sections through the T Tank and the TX-TY Tank Farm. Eight cases were carried out for the cross sections to simulate the effects of interim barrier, water line leak, inventory distribution, and surface recharge on water flow and the transport of long-lived radionuclides (i.e., technecium-99 and uranium) and chemicals (i.e., nitrate and chromium For simulations with barriers, it is assumed that an interim barrier is in place by the year 2010. It was also assumed that, for all simulations, as part of tank farm closure, a closure barrier was in place by the year 2040. The modeling considers the estimated inventories of contaminants within the vadose zone and calculates the associated risk. It assumes that no tanks will leak in the future. Initial conditions for contaminant concentration are provided as part of inventory estimates for uranium, technetium-99, nitrate, and chromium. For moisture flow modeling, Neumann boundary conditions are prescribed at the surface with the flux equal to the recharge rate estimate. For transport modeling, a zero flux boundary is prescribed at the surface for uranium, technetium-99, nitrate, and chromium. The western and eastern boundaries are assigned no-flux boundaries for both flow and transport. The water table boundary is prescribed by water table elevations and the unconfined aquifer hydraulic gradient. No-flux boundaries are used for the lower boundary

  5. Do colours affect 'normal' behaviour of laboratory and farm animals? Instantaneous change of behaviour by presentation of red in the Peach-F.

    PubMed

    Mebes, H D

    1979-06-01

    In spite of genetic and environmental standardisation in farm and laboratory animal science, a considerable amount of variation in the results of comparable experiments remains. This presumably depends upon the individual variability within a species, and upon differences of various species in their specific demands to the environment in captivity. Due to a discovery in the Southwest-African lovebird species Agapornis roseicollis, used as a conventional laboratory animal in bioacoustic research, the phenomenon of instantaneous fear expressed in a number of different displays in connection with the presence or presentation of red objects is described and compared to earlier observations of instantaneous phobias, aggressions, and preferences towards colours, in other bird species. Consequently it is suggested that investigation of the chromatophobe and chromatophile behaviour of typical laboratory and farm animals be undertaken to ensure the adequate design of lodging and experimental environments.

  6. Coupling the Weather Research and Forecasting (WRF) model and Large Eddy Simulations with Actuator Disk Model: predictions of wind farm power production

    NASA Astrophysics Data System (ADS)

    Garcia Cartagena, Edgardo Javier; Santoni, Christian; Ciri, Umberto; Iungo, Giacomo Valerio; Leonardi, Stefano

    2015-11-01

    A large-scale wind farm operating under realistic atmospheric conditions is studied by coupling a meso-scale and micro-scale models. For this purpose, the Weather Research and Forecasting model (WRF) is coupled with an in-house LES solver for wind farms. The code is based on a finite difference scheme, with a Runge-Kutta, fractional step and the Actuator Disk Model. The WRF model has been configured using seven one-way nested domains where the child domain has a mesh size one third of its parent domain. A horizontal resolution of 70 m is used in the innermost domain. A section from the smallest and finest nested domain, 7.5 diameters upwind of the wind farm is used as inlet boundary condition for the LES code. The wind farm consists in six-turbines aligned with the mean wind direction and streamwise spacing of 10 rotor diameters, (D), and 2.75D in the spanwise direction. Three simulations were performed by varying the velocity fluctuations at the inlet: random perturbations, precursor simulation, and recycling perturbation method. Results are compared with a simulation on the same wind farm with an ideal uniform wind speed to assess the importance of the time varying incoming wind velocity. Numerical simulations were performed at TACC (Grant CTS070066). This work was supported by NSF, (Grant IIA-1243482 WINDINSPIRE).

  7. Steady-State Simulation of Steam Reforming of INEEL Tank Farm Waste

    SciTech Connect

    Nichols, T.T.; Taylor, D.D.; Wood, R.A.; Barnes, C.M.

    2002-08-15

    A steady-state model of the Sodium-Bearing Waste steam reforming process at the Idaho National Engineering and Environmental Laboratory has been performed using the commercial ASPEN Plus process simulator. The preliminary process configuration and its representation in ASPEN are described. As assessment of the capability of the model to mechanistically predict product stream compositions was made, and fidelity gaps and opportunities for model enhancement were identified, resulting in the following conclusions: (1) Appreciable benefit is derived from using an activity coefficient model for electrolyte solution thermodynamics rather than assuming ideality (unity assumed for all activity coefficients). The concentrations of fifteen percent of the species present in the primary output stream were changed by more than 50%, relative to Electrolyte NRTL, when ideality was assumed; (2) The current baseline model provides a good start for estimating mass balances and performing integrated process optimization because it contains several key species, uses a mechanistic electrolyte thermodynamic model, and is based on a reasonable process configuration; and (3) Appreciable improvement to model fidelity can be realized by expanding the species list and the list of chemical and phase transformations. A path forward is proposed focusing on the use of an improved electrolyte thermodynamic property method, addition of chemical and phase transformations for key species currently absent from the model, and the combination of RGibbs and Flash blocks to simulate simultaneous phase and chemical equilibria in the off-gas treatment train.

  8. Steady-State Simulation of Steam Reforming of INEEL Tank Farm Waste

    SciTech Connect

    Nichols, Todd Travis; Taylor, Dean Dalton; Wood, Richard Arthur; Barnes, Charles Marshall

    2002-08-01

    A steady-state model of the Sodium-Bearing Waste steam reforming process at the Idaho National Engineering and Environmental Laboratory has been performed using the commercial ASPEN Plus process simulator. The preliminary process configuration and its representation in ASPEN are described. As assessment of the capability of the model to mechanistically predict product stream compositions was made, and fidelity gaps and opportunities for model enhancement were identified, resulting in the following conclusions: 1) Appreciable benefit is derived from using an activity coefficient model for electrolyte solution thermodynamics rather than assuming ideality (unity assumed for all activity coefficients). The concentrations of fifteen percent of the species present in the primary output stream were changed by more than 50%, relative to Electrolyte NRTL, when ideality was assumed; 2) The current baseline model provides a good start for estimating mass balances and performing integrated process optimization because it contains several key species, uses a mechanistic electrolyte thermodynamic model, and is based on a reasonable process configuration; and 3) Appreciable improvement to model fidelity can be realized by expanding the species list and the list of chemical and phase transformations. A path forward is proposed focusing on the use of an improved electrolyte thermodynamic property method, addition of chemical and phase transformations for key species currently absent from the model, and the combination of RGibbs and Flash blocks to simulate simultaneous phase and chemical equilibria in the off-gas treatment train.

  9. Simulated impacts of climate change on current farming locations of striped catfish (Pangasianodon hypophthalmus; Sauvage) in the Mekong Delta, Vietnam.

    PubMed

    Nguyen, Anh L; Dang, Vinh H; Bosma, Roel H; Verreth, Johan A J; Leemans, Rik; De Silva, Sena S

    2014-12-01

    In Vietnam, culturing striped catfish makes an important contribution to the Mekong Delta's economy. Water level rise during rainy season and salt intrusion during dry season affect the water exchange and quality for this culture. Sea level rise as a consequence of climate change will worsen these influences. In this study, water level rise and salt water intrusion for three sea level rise (SLR) scenarios (i.e., +30, +50, and +75 cm) were simulated. The results showed that at SLR +50, the 3-m-flood level would spread downstream and threaten farms located in AnGiang, DongThap and CanTho provinces. Rising salinity levels for SLR +75 would reduce the window appropriate for the culture in SocTrang and BenTre provinces, and in TienGiang's coastal districts. Next to increasing dikes to reduce the impacts, the most tenable and least disruptive option to the farming community would be to shift to a salinity tolerant strain of catfish.

  10. Design and simulation on the morphing composite propeller (Conference Presentation)

    NASA Astrophysics Data System (ADS)

    Chen, Fanlong; Li, Qinyu; Liu, Liwu; Lan, Xin; Liu, Yanju; Leng, Jinsong

    2017-04-01

    As one of the most crucial part of the unmanned underwater vehicle (UUV), the composite propeller plays an important role on the UUV's performance. As the composite propeller behaves excellent properties in hydroelastic facet and acoustic suppression, it attracts increasing attentions all over the globe. This paper goes a step further based on this idea, and comes up with a novel concept of "morphing composite propeller" (MCP) to improve the performance of the conventional composite propeller (CCP) to anticipate the improved propeller can perform better to propel the UUV. Based on the new concept, a novel MCP is designed. Each blade of the propeller is assembled with an active rotatable flap (ARF) to change the blade's local camber with flap rotation. Then the transmission mechanism (TM) has been designed and housed in the propeller blade to push the ARF. With the ARF rotating, the UUV can be propelled by different thrusts under certain rotation velocities of the propeller. Based on the design, the Fluent is exploited to analyze the fluid dynamics around the propeller. Finally, based on the design and hydrodynamic analysis, the structural response for the novel morphing composite propeller is calculated. The propeller blade is simplified and layered with composite materials. And the structure response of an MCP is obtained with various rotation angle under the hydrodynamic pressure. This simulation can instruct the design and fabrication techniques of the MCP.

  11. Carbocyanines in an RNA environment: experiment meets simulation (Conference Presentation)

    NASA Astrophysics Data System (ADS)

    Boerner, Richard; Steffen, Fabio; Sigel, Roland K. O.

    2016-02-01

    The popularity of carbocyanine dyes in single molecule spectroscopy of nucleic acids is unbroken [1]. Studying the dynamics of large RNA constructs and the binding kinetics such as the exon/intron binding side interaction of the group II intron in S. Cerevisiae [2,3] have motivated a thorough photophysical characterization of the FRET pair Cy3/Cy5 in context of nucleic acids and RNA in particular. We show that Mg2+ as a mediator of RNA-dye interactions enhances the cyanine fluorescence lifetime. The increasing window for depolarization as monitored by time-resolved anisotropy further revealed a dynamic equilibrium between free tumbling and stacking on the RNA backbone, with the stacked conformation preventing photoisomerization [4]. Tracking fluorophore mobility covalently bound to the RNA on an atomistic level by means of molecular dynamics [5] allow to disentangle different types of dye-dye and dye-RNA interactions. Our hybrid approach combining time-correlated single photon counting and computer simulations will benefit the interpretation of absolute distance measurement by smFRET. [1] M.Levitus and S.Ranjit, Q. Rev. Biophys 2011, 44, 123-151. [2] D.Kowerko, S.L.B.König, M.Skilandat, D.Kruschel, M.C.A.S.Hadzic, L.Cardo, R.K.O.Sigel, PNAS 2015, 112, 3403-3408. [3] M. Khier, D. Kowerko, F. Steffen, R. Börner and R.K.O.Sigel, in preparation. [4] F.Steffen, R.K.O. Sigel, R.Börner, in preparation. [5] R.Best, H. Hofmann, D. Nettels, B. Schuler, Biophys J 2015, 11,2721-2731.

  12. Biodegradation of creosote and pentachlorophenol using simulated land farming techniques. Master`s thesis

    SciTech Connect

    Hodge, T.D.

    1995-10-01

    The objective of this project was to evaluate five land farming treatments, to determine which would best remediate creosote and pentachlorophenol contamination at and around a wood preservation treatment facility, and to determine the feasibility of applying such a treatment. These treatments were: (i) addition of water, (ii) addition of white rot fungus (Phanaerochete chrysosponum) and water, (iii) addition of an inoculum of bacterial isolates and water, (iv) addition of a soil inoculum from a previously remediated facility and water, and (v) addition of sodium nitrate and water. The soil that was investigated came from a facility in Camilla, Georgia. This site had been used to impregnate a variety of wood products with creosote and (PCP). The soil was so highly contaminated that only a minimal number of microorganisms could be cultured from the samples that were on hand. It is likely that those organisms which were viable evolved some ability to metabolize these pollutants.

  13. Sinonasal Globular Amyloidosis Simulating Malignancy: A Rare Presentation.

    PubMed

    Kumar, Binay; Pant, Bhawna; Kumar, Vikrant; Negi, Meghna

    2016-09-01

    Primary localized amyloidosis in the head and neck region is a rare entity. The most commonly involved organ is larynx. Primary amyloidosis localized to the sinonasal tract is extremely rare. We report one such case along with a brief review of the associated literature. The aim of reporting this case is to emphasize the fact that sometimes nasal amyloidosis can also present with signs and symptoms of nasal and nasopharyngeal malignancy. The definitive diagnosis in such cases depends upon histopathology and further confirmed by immunohistochemistry. A 55-year old male presented with recurrent episodes of nasal bleed, bilateral nasal obstruction, and bilateral hearing loss from last 7 years. On clinical examination a mass was found in the nasal cavity on both sides reaching up to the nasopharynx. Contrast enhanced CT scan revealed that the mass was extending up to the skull base and destroying bony landmarks of the nasal cavity and paranasal sinuses. Mass was proved to be amyloidosis after histopathological examination. It showed multiple blotches of globular submucosal deposit of amyloid, on staining with Congo red. Immunohistochemistry confirmed AL amyloidosis with expression of mixed kappa and lambda light chain immunoglobulin (κ > λ). No evidence of systemic amyloidosis was found after proper work up. It was managed by conservative surgery.

  14. Turbulence and entrainment length scales in large wind farms

    NASA Astrophysics Data System (ADS)

    Andersen, Søren J.; Sørensen, Jens N.; Mikkelsen, Robert F.

    2017-03-01

    A number of large wind farms are modelled using large eddy simulations to elucidate the entrainment process. A reference simulation without turbines and three farm simulations with different degrees of imposed atmospheric turbulence are presented. The entrainment process is assessed using proper orthogonal decomposition, which is employed to detect the largest and most energetic coherent turbulent structures. The dominant length scales responsible for the entrainment process are shown to grow further into the wind farm, but to be limited in extent by the streamwise turbine spacing, which could be taken into account when developing farm layouts. The self-organized motion or large coherent structures also yield high correlations between the power productions of consecutive turbines, which can be exploited through dynamic farm control. This article is part of the themed issue 'Wind energy in complex terrains'.

  15. Turbulence and entrainment length scales in large wind farms.

    PubMed

    Andersen, Søren J; Sørensen, Jens N; Mikkelsen, Robert F

    2017-04-13

    A number of large wind farms are modelled using large eddy simulations to elucidate the entrainment process. A reference simulation without turbines and three farm simulations with different degrees of imposed atmospheric turbulence are presented. The entrainment process is assessed using proper orthogonal decomposition, which is employed to detect the largest and most energetic coherent turbulent structures. The dominant length scales responsible for the entrainment process are shown to grow further into the wind farm, but to be limited in extent by the streamwise turbine spacing, which could be taken into account when developing farm layouts. The self-organized motion or large coherent structures also yield high correlations between the power productions of consecutive turbines, which can be exploited through dynamic farm control.This article is part of the themed issue 'Wind energy in complex terrains'.

  16. Flight simulators. Part 1: Present situation and trends. Part 2: Implications for training

    NASA Technical Reports Server (NTRS)

    Hass, D.; Volk, W.

    1977-01-01

    The present situation and developments in the technology of flight simulators based on digital computers are evaluated from the standpoint of training airline flight crews. Areas covered are minicomputers and their advantages in terms of cost, space and time savings, software data packets, motion simulation, visual simulation and instructor aids. The division of training time between aircraft and simulator training and the possible advantages from increased use of simulators are evaluated.

  17. The Subsistence Agriculture Game: A Simulation of Farming. Instructional Activities Series IA/S-17.

    ERIC Educational Resources Information Center

    Martinson, Tom; Harnapp, Vern

    This activity is one of a series of 17 teacher-developed instructional activities for geography at the secondary-grade level described in SO 009 140. Through a simulation, students develop an understanding of subsistence agriculture in Central America and how it is influenced by cultural and physical factors. During four 50-minute class periods,…

  18. Full vector (3-D) inflow simulation in natural and wind farm environments using an expanded version of the SNLWIND (Veers) turbulence code

    SciTech Connect

    Kelley, N.D.

    1992-11-01

    We have recently expanded the numerical turbulence simulation (SNLWIND) developed by Veers [1] to include all three components of the turbulent wind vector. We have also configured the code to simulate the characteristics of turbulent wind fields upwind and downwind of a large wind farm, as well as over uniform, flat terrain. Veers`s original method only simulates the longitudinal component of the wind in neutral flow. This paper overviews the development of spectral distribution, spatial coherence, and cross correlation models used to expired the SNLWIND code to include the three components of the turbulent wind over a range of atmospheric stabilities. These models are based on extensive measurements of the turbulence characteristics immediately upwind and downwind of a large wind farm in San Gorgonio Pass, California.

  19. A computer simulation study to evaluate resistance development with a derquantel-abamectin combination on UK sheep farms.

    PubMed

    Learmount, J; Taylor, M A; Bartram, D J

    2012-06-08

    UK guidelines for the sustainable control of parasites in sheep (SCOPS) aim to delay further development of anthelmintic drug resistance. This study describes a computer model evaluation of resistance development with a novel oral formulation of derquantel-abamectin, to inform recommendations for use. Two different farm management scenarios, based on UK field data, were modelled to simulate low refugia (non SCOPS) or high refugia (SCOPS) worm populations. The effect on resistance allele frequencies and field efficacy of several treatment scenarios using the novel active derquantel (DQL), a spiroindole (SI), as either a single or multiple active formulation with abamectin (ABA), a macrocyclic lactone (ML), under the two farm management systems was evaluated. The initial resistance allele frequency for DQL was set at 0.0001, assuming that resistance in the UK is low, and for ML at 0.165 or 0.8, assuming that resistant nematode populations exist in the UK. DQL resistance reached a level at which a reduction in field efficacy might be detected (resistance allele frequency 0.25) by year 16 when used sequentially, and by year 31 when used in annual rotation (ABA) with SCOPS management inputs, and by year 5 (sequential) and by year 10 (annual rotation) with non SCOPS management inputs. ML resistance reached a level at which a reduction in ABA field efficacy might be detected (resistance allele frequency 0.25) by year 4 when used sequentially, and by year 8 when used in annual rotation with DQL and SCOPS management inputs, and by year 1 (sequential) and by year 2 (annual rotation) with non SCOPS management inputs. No detectable reduction in field efficacy was observed for DQL-ABA after 40 years of use with SCOPS management inputs for simulations using an initial ML resistance allele frequency of 0.165 and 0.8. A detectable reduction in field efficacy was observed for DQL-ABA by year 32 (initial ML resistance allele frequency=0.165) and by year 6 (initial ML resistance

  20. Space-time modelling of the spread of salmon lice between and within Norwegian marine salmon farms.

    PubMed

    Aldrin, Magne; Storvik, Bård; Kristoffersen, Anja Bråthen; Jansen, Peder Andreas

    2013-01-01

    Parasitic salmon lice are potentially harmful to salmonid hosts and farm produced lice pose a threat to wild salmonids. To control salmon lice infections in Norwegian salmonid farming, numbers of lice are regularly counted and lice abundance is reported from all salmonid farms every month. We have developed a stochastic space-time model where monthly lice abundance is modelled simultaneously for all farms. The set of farms is regarded as a network where the degree of contact between farms depends on their seaway distance. The expected lice abundance at each farm is modelled as a function of i) lice abundance in previous months at the same farm, ii) at neighbourhood farms, and iii) other, unspecified sources. In addition, the model includes explanatory variables such as seawater temperature and farm-numbers of fish. The model gives insight into factors that affect salmon lice abundance and contributing sources of infection. New findings in this study were that 66% of the expected salmon lice abundance was attributed to infection within farms, 28% was attributed to infection from neighbourhood farms and 6% to non-specified sources of infection. Furthermore, we present the relative risk of infection between neighbourhood farms as a function of seaway distance, which can be viewed as a between farm transmission kernel for salmon lice. The present modelling framework lays the foundation for development of future scenario simulation tools for examining the spread and abundance of salmon lice on farmed salmonids under different control regimes.

  1. Space-Time Modelling of the Spread of Salmon Lice between and within Norwegian Marine Salmon Farms

    PubMed Central

    Aldrin, Magne; Storvik, Bård; Kristoffersen, Anja Bråthen; Jansen, Peder Andreas

    2013-01-01

    Parasitic salmon lice are potentially harmful to salmonid hosts and farm produced lice pose a threat to wild salmonids. To control salmon lice infections in Norwegian salmonid farming, numbers of lice are regularly counted and lice abundance is reported from all salmonid farms every month. We have developed a stochastic space-time model where monthly lice abundance is modelled simultaneously for all farms. The set of farms is regarded as a network where the degree of contact between farms depends on their seaway distance. The expected lice abundance at each farm is modelled as a function of i) lice abundance in previous months at the same farm, ii) at neighbourhood farms, and iii) other, unspecified sources. In addition, the model includes explanatory variables such as seawater temperature and farm-numbers of fish. The model gives insight into factors that affect salmon lice abundance and contributing sources of infection. New findings in this study were that 66% of the expected salmon lice abundance was attributed to infection within farms, 28% was attributed to infection from neighbourhood farms and 6% to non-specified sources of infection. Furthermore, we present the relative risk of infection between neighbourhood farms as a function of seaway distance, which can be viewed as a between farm transmission kernel for salmon lice. The present modelling framework lays the foundation for development of future scenario simulation tools for examining the spread and abundance of salmon lice on farmed salmonids under different control regimes. PMID:23700455

  2. Simulate what is measured: next steps towards predictive simulations (Conference Presentation)

    NASA Astrophysics Data System (ADS)

    Bussmann, Michael; Kluge, Thomas; Debus, Alexander; Hübl, Axel; Garten, Marco; Zacharias, Malte; Vorberger, Jan; Pausch, Richard; Widera, René; Schramm, Ulrich; Cowan, Thomas E.; Irman, Arie; Zeil, Karl; Kraus, Dominik

    2017-05-01

    Simulations of laser matter interaction at extreme intensities that have predictive power are nowadays in reach when considering codes that make optimum use of high performance compute architectures. Nevertheless, this is mostly true for very specific settings where model parameters are very well known from experiment and the underlying plasma dynamics is governed by Maxwell's equations solely. When including atomic effects, prepulse influences, radiation reaction and other physical phenomena things look different. Not only is it harder to evaluate the sensitivity of the simulation result on the variation of the various model parameters but numerical models are less well tested and their combination can lead to subtle side effects that influence the simulation outcome. We propose to make optimum use of future compute hardware to compute statistical and systematic errors rather than just find the mots optimum set of parameters fitting an experiment. This requires to include experimental uncertainties which is a challenge to current state of the art techniques. Moreover, it demands better comparison to experiments as inclusion of simulating the diagnostic's response becomes important. We strongly advocate the use of open standards for finding interoperability between codes for comparison studies, building complete tool chains for simulating laser matter experiments from start to end.

  3. Simulating nitrogen budgets in complex farming systems using INCA: calibration and scenario analyses for the Kervidy catchment (W. France)

    NASA Astrophysics Data System (ADS)

    Durand, P.

    The integrated nitrogen model INCA (Integrated Nitrogen in Catchments) was used to analyse the nitrogen dynamics in a small rural catchment in Western France. The agrosystem studied is very complex, with: extensive use of different organic fertilisers, a variety of crop rotations, a structural excess of nitrogen (i.e. more animal N produced by the intensive farming than the N requirements of the crops and pastures), and nitrate retention in both hydrological stores and riparian zones. The original model features were adapted here to describe this complexity. The calibration results are satisfactory, although the daily variations in stream nitrate are not simulated in detail. Different climate scenarios, based on observed climate records, were tested; all produced a worsening of the pollution in the short term. Scenarios of alternative agricultural practices (reduced fertilisation and catch crops) were also analysed, suggesting that a reduction by 40% of the fertilisation combined with the introduction of catch crops would be necessary to stop the degradation of water quality.

  4. Effects of Multiple Simulation Presentation among Students of Different Anxiety Levels in the Learning of Probability

    ERIC Educational Resources Information Center

    Fong, Soon Fook; Por, Fei Ping; Tang, Ai Ling

    2012-01-01

    The purpose of this study was to investigate the effects of multiple simulation presentation in interactive multimedia are on the achievement of students with different levels of anxiety in the learning of Probability. The interactive multimedia courseware was developed in two different modes, which were Multiple Simulation Presentation (MSP) and…

  5. Presentation of Fukushima Analyses to U.S. Nuclear Power Plant Simulator Operators and Vendors

    SciTech Connect

    Osborn, Douglas; Kalinich, Donald A.; Cardoni, Jeffrey N

    2015-02-01

    This document provides Sandia National Laboratories’ meeting notes and presentations at the Society for Modeling and Simulation Power Plant Simulator conference in Jacksonville, FL. The conference was held January 26-28, 2015, and SNL was invited by the U.S. nuclear industry to present Fukushima modeling insights and lessons learned.

  6. Adding Complex Terrain and Stable Atmospheric Condition Capability to the OpenFOAM-based Flow Solver of the Simulator for On/Offshore Wind Farm Applications (SOWFA): Preprint

    SciTech Connect

    Churchfield, M. J.; Sang, L.; Moriarty, P. J.

    2013-09-01

    This paper describes changes made to NREL's OpenFOAM-based wind plant aerodynamics solver such that it can compute the stably stratified atmospheric boundary layer and flow over terrain. Background about the flow solver, the Simulator for Off/Onshore Wind Farm Applications (SOWFA) is given, followed by details of the stable stratification/complex terrain modifications to SOWFA, along with somepreliminary results calculations of a stable atmospheric boundary layer and flow over a simply set of hills.

  7. Multi-agent modeling and simulation of farmland use change in the farming-pastoral zone: A case study of Qianjingou Town in Inner Mongolia, China

    NASA Astrophysics Data System (ADS)

    Yan, H.

    2015-12-01

    Farmland is the most basic material conditions for guaranteeing rural livelihoods and national food security, and exploring management strategies that take both of the sustainable rural livelihoods and sustainable farmland use into account has vital significance of theory and practice. Farmland is a complex and self-adaptive system that couples human and natural systems together, and natural factors and social factors that are related to its changing process need to be considered when modeling farmland changing process. This paper takes Qianjingou Town in Inner Mongolia farming-pastoral zone as study area. From the perspective of the relationship between households' livelihoods and farmland use, this study builds the process mechanism of farmland use change based on questionnaires data, and constructs multi-agent simulation model of farmland use change with the help of Eclipse and Repast toolbox. Through simulating the relationship between natural factors (with geographical location) and households' behaviors, this paper systematically simulates households' renting and abandoning farmland behaviors, and truly describes dynamic interactions between households' livelihoods and factors related to farmland use change. These factors include natural factors (net primary productivity, road accessibility, slope and relief amplitude) and social factors (households' family structures, economic development and government policies). In the end, this study scientifically predicts farmland use change trend in the future 30 years. The simulation results show that, the number of abandoned and sublet farmland plots has a gradually increasing trend, the number of non-farm households and pure-outwork households has a remarkable increasing trend, and the number of part-farm households and pure-farm households shows a decreasing trend. Households' livelihoods sustainability in the study area is confronted with increasing pressure, and households' nonfarm employment has an increasing

  8. Teaching Engineering Statistics with Technology, Group Learning, Contextual Projects, Simulation Models and Student Presentations

    ERIC Educational Resources Information Center

    Romeu, Jorge Luis

    2008-01-01

    This article discusses our teaching approach in graduate level Engineering Statistics. It is based on the use of modern technology, learning groups, contextual projects, simulation models, and statistical and simulation software to entice student motivation. The use of technology to facilitate group projects and presentations, and to generate,…

  9. Teaching Engineering Statistics with Technology, Group Learning, Contextual Projects, Simulation Models and Student Presentations

    ERIC Educational Resources Information Center

    Romeu, Jorge Luis

    2008-01-01

    This article discusses our teaching approach in graduate level Engineering Statistics. It is based on the use of modern technology, learning groups, contextual projects, simulation models, and statistical and simulation software to entice student motivation. The use of technology to facilitate group projects and presentations, and to generate,…

  10. Webinar Presentation: Particle-Resolved Simulations for Quantifying Black Carbon Climate Impact and Model Uncertainty

    EPA Pesticide Factsheets

    This presentation, Particle-Resolved Simulations for Quantifying Black Carbon Climate Impact and Model Uncertainty, was given at the STAR Black Carbon 2016 Webinar Series: Changing Chemistry over Time held on Oct. 31, 2016.

  11. Constrictive pericarditis presenting with an outpouching of the right ventricle free wall simulating an aneurysmal dilatation.

    PubMed

    Ocak, I; Turkbey, B; Lacomis, J M

    2011-03-01

    We present a case of constrictive pericarditis resulting in an outpouching of the right ventricular free wall, simulating a right ventricular free wall aneurysm. The present case is, to the best of our knowledge, the first reported right ventricular free wall aneurysm-like outpouching adjacent to surrounding regions of thickened pericardium in a patient with constrictive pericarditis.

  12. Analysis of simulated angiographic procedures: part 1--capture and presentation of audio and video recordings.

    PubMed

    Duncan, James R; Glaiberman, Craig B

    2006-12-01

    To assess different methods of recording angiographic simulations and to determine how such recordings might be used for training and research. Two commercially available high-fidelity angiography simulations, the Mentice Vascular Interventional Simulation Trainer and the Simbionix AngioMentor, were used for data collection. Video and audio records of simulated procedures were created by different methods, including software-based screen capture, video splitters and converters, and external cameras. Recording parameters were varied, and the recordings were transferred to computer workstations for postprocessing and presentation. The information displayed on the simulators' computer screens could be captured by each method. Although screen-capture software provided the highest resolution, workflow considerations favored a hardware-based solution that duplicated the video signal and recorded the data stream(s) at lower resolutions. Additional video and audio recording devices were used to monitor the angiographer's actions during the simulated procedures. The multiple audio and video files were synchronized and composited with personal computers equipped with commercially available video editing software. Depending on the needs of the intended audience, the resulting files could be distributed and displayed at full or reduced resolutions. The capture, editing, presentation, and distribution of synchronized multichannel audio and video recordings holds great promise for angiography training and simulation research. To achieve this potential, technical challenges will need to be met, and content will need to be tailored to suit the needs of trainees and researchers.

  13. Simulating tissue fiberation and polarization properties in solid phantoms (Conference Presentation)

    NASA Astrophysics Data System (ADS)

    Wang, Haili; Shen, Shu Wei; Qu, Yingjie; Sun, Mingzhai Z.; Dong, Erbao; Shao, Peng Fei; Xu, Ronald X.

    2017-03-01

    Polarization of biological tissue reflects birefringent characteristics of tissue components such as collagenous and elastic fibers. Polarimetry imaging techniques have been widely explored for disease diagnosis and therapeutic guidance. However, no traceable standard is available for calibration and validation of the polarimetry devices, partially due to the lack of reliable and stable tissue-simulating phantoms that simulate tissue birefringence properties. We propose a new method to fabricate tissue simulating phantoms that simulate tissue scattering and polarization characteristics. The substrate of the phantoms are made of polydimethylsiloxane (PDMS). The PDMS material is mixed with sucrose to simulate optical rotation characteristics of chiral molecules in tissue. Titanum dioxide (TiO2 ) particles are used to simulate organelle scattering properties of tissue. An electrostatic spinning method produces thin filaments with designated orientation and polarization characteristics to simulate collagen and elastic fiber orientation in biological tissue.By adjusting the concentration of the scattering particles and the arrangements of the fibers, the produced phantoms present different polarization characteristics. The proposed tissue-simulating phantoms can be potentially used to validate and calibrate the polarimetry medical devices.

  14. A Case of Aortopulmonary Window Simulating Common Arterial Trunk Presented at the Age of 13

    SciTech Connect

    Cetin, Ibrahim Ilker; Oruen, Utku Arman; Varan, Birguel; Coskun, Mehmet; Tokel, Kuersad

    2005-05-15

    We have reported a patient with aortopulmonary window (APW) simulating truncus. In classically defined APW, aorta and main pulmonary artery separate again after a distance from the window and form the aortic arch and pulmonary arteries. However, in our case, there was no separation and they formed a very large pouch from which the great vessels originated. Thus, we believe that we have presented the first case of APW simulating truncus, but with two separate semilunar valves.

  15. Grid Integration of Wind Farms

    NASA Astrophysics Data System (ADS)

    Giæver Tande, John Olav

    2003-07-01

    This article gives an overview of grid integration of wind farms with respect to impact on voltage quality and power system stability. The recommended procedure for assessing the impact of wind turbines on voltage quality in distribution grids is presented. The procedure uses the power quality characteristic data of wind turbines to determine the impact on slow voltage variations, flicker, voltage dips and harmonics. The detailed assessment allows for substantially more wind power in distribution grids compared with previously used rule-of-thumb guidelines. Power system stability is a concern in conjunction with large wind farms or very weak grids. Assessment requires the use of power system simulation tools, and wind farm models for inclusion in such tools are presently being developed. A fixed-speed wind turbine model is described. The model may be considered a good starting point for development of more advanced models, hereunder the concept of variable-speed wind turbines with a doubly fed induction generator is briefly explained. The use of dynamic wind farm models as part of power system simulation tools allows for detailed studies and development of innovative grid integration techniques. It is demonstrated that the use of reactive compensation may relax the short-term voltage stability limit and allow integration of significantly more wind power, and that application of automatic generation control technology may be an efficient means to circumvent thermal transmission capacity constraints. The continuous development of analysis tools and technology for cost-effective and secure grid integration is an important aid to ensure the increasing use of wind energy. A key factor for success, however, is the communication of results and gained experience, and in this regard it is hoped that this article may contribute.

  16. WRF-Cordex simulations for Europe: mean and extreme precipitation for present and future climates

    NASA Astrophysics Data System (ADS)

    Cardoso, Rita M.; Soares, Pedro M. M.; Miranda, Pedro M. A.

    2013-04-01

    The Weather Research and Forecast (WRF-ARW) model, version 3.3.1, was used to perform the European domain Cordex simulations, at 50km resolution. A first simulation, forced by ERA-Interim (1989-2009), was carried out to evaluate the models performance to represent the mean and extreme precipitation in present European climate. This evaluation is based in the comparison of WRF results against the ECAD regular gridded dataset of daily precipitation. Results are comparable to recent studies with other models for the European region, at this resolution. For the same domain a control and a future scenario (RCP8.5) simulation was performed to assess the climate change impact on the mean and extreme precipitation. These regional simulations were forced by EC-EARTH model results, and, encompass the periods from 1960-2006 and 2006-2100, respectively.

  17. Pre-industrial to Present Day Chemistry Model Simulations: The Role of Different Forcings

    NASA Astrophysics Data System (ADS)

    Young, P. J.; Lamarque, J.; Kinnison, D. E.; Vitt, F.

    2011-12-01

    We will present the results from several CAM-Chem simulations that span 1850-2010. Simulations where one forcing is fixed at 1850 (or 1930) levels are compared against a "base" simulation, where all the forcings evolve through time. The "fixed" simulations respectively hold (1) methane, (2) all surface/aloft emissions, (3) only aerosol emissions, (4) sea surface temperatures/CO2 (i.e. climate) at their 1850 level, and (5) CFCs at their 1930 level. We will examine the sensitivity of the ozone budget and methane lifetime results under these various scenarios. In particular, we will discuss the potential role of complex interactions in defining the tropospheric ozone burden change. We will make use of those results as a basis for the understanding of the spread in fields from the ongoing Atmospheric Chemistry and Climate Model Intercomparison Project (ACCMIP).

  18. 3D printing of microtube in solid phantom to simulate tissue oxygenation and perfusion (Conference Presentation)

    NASA Astrophysics Data System (ADS)

    Lv, Xiang; Xue, Yue; Wang, Haili; Shen, Shu Wei; Zhou, Ximing; Liu, Guangli; Dong, Erbao; Xu, Ronald X.

    2017-03-01

    Tissue-simulating phantoms with interior vascular network may facilitate traceable calibration and quantitative validation of many medical optical devices. However, a solid phantom that reliably simulates tissue oxygenation and blood perfusion is still not available. This paper presents a new method to fabricate hollow microtubes for blood vessel simulation in solid phantoms. The fabrication process combines ultraviolet (UV) rapid prototyping technique with fluid mechanics of a coaxial jet flow. Polydimethylsiloxane (PDMS) and a UV-curable polymer are mixed at the designated ratio and extruded through a coaxial needle device to produce a coaxial jet flow. The extruded jet flow is quickly photo-polymerized by ultraviolet (UV) light to form vessel-simulating solid structures at different sizes ranging from 700 μm to 1000 μm. Microtube structures with adequate mechanical properties can be fabricated by adjusting material compositions and illumination intensity. Curved, straight and stretched microtubes can be formed by adjusting the extrusion speed of the materials and the speed of the 3D printing platform. To simulate vascular structures in biologic tissue, we embed vessel-simulating microtubes in a gel wax phantom of 10 cm x10 cm x 5 cm at the depth from 1 to 2 mm. Bloods at different oxygenation and hemoglobin concentration levels are circulated through the microtubes at different flow rates in order to simulate different oxygenation and perfusion conditions. The simulated physiologic parameters are detected by a tissue oximeter and a laser speckle blood flow meter respectively and compared with the actual values. Our experiments demonstrate that the proposed 3D printing process is able to produce solid phantoms with simulated vascular networks for potential applications in medical device calibration and drug delivery studies.

  19. Bittersweet Farms.

    ERIC Educational Resources Information Center

    Kay, Bettye Ruth

    1990-01-01

    The article describes Bittersweet Farms, a rural Ohio farm community for autistic adults. The program is based on the rural, extended family community as a model and includes work components (horticulture, animal care, woodworking and carpentry, maintenance, housekeeping, food preparation), recreational activities, community integration, physical…

  20. Bittersweet Farms.

    ERIC Educational Resources Information Center

    Kay, Bettye Ruth

    1990-01-01

    The article describes Bittersweet Farms, a rural Ohio farm community for autistic adults. The program is based on the rural, extended family community as a model and includes work components (horticulture, animal care, woodworking and carpentry, maintenance, housekeeping, food preparation), recreational activities, community integration, physical…

  1. Full 3D opto-electronic simulation tool for nanotextured solar cells (Conference Presentation)

    NASA Astrophysics Data System (ADS)

    Michallon, Jérôme; Collin, Stéphane

    2017-04-01

    Increasing efforts on the photovoltaics research have recently been devoted to material savings, leading to the emergence of new designs based on nanotextured and nanowire-based solar cells. The use of small absorber volumes, light-trapping nanostructures and unconventional carrier collection schemes (radial nanowire junctions, point contacts in planar structures,…) increases the impact of surfaces recombination and induces homogeneity in the photogenerated carrier concentrations. The investigation of their impacts on the device performances need to be addressed using full 3D coupled opto-electrical modeling. In this context, we have developed a new tool for full 3D opto-electrical simulation using the most advanced optical and electrical simulation techniques. We will present an overview of its simulation capabilities and the key issues that have been solved to make it fully operational and reliable. We will provide various examples of opto-electronic simulation of (i) nanostructured solar cells with localized contacts and (ii) nanowire solar cells. We will also show how opto-electronic simulation can be used to simulate light- and electron-beam induced current (LBIC/EBIC) experiments, targeting quantitative analysis of the passivation properties of surfaces.

  2. A multi-physics ensemble of present-day climate regional simulations over the Iberian Peninsula

    NASA Astrophysics Data System (ADS)

    Jerez, Sonia; Montavez, Juan Pedro; Jimenez-Guerrero, Pedro; Gomez-Navarro, Juan Jose; Lorente-Plazas, Raquel; Zorita, Eduardo

    2013-06-01

    This work assesses the influence of the model physics in present-day regional climate simulations. It is based on a multi-phyiscs ensemble of 30-year long MM5 hindcasted simulations performed over a complex and climatically heterogeneous domain as the Iberian Peninsula. The ensemble consists of eight members that results from combining different parametrization schemes for modeling the Planetary Boundary Layer, the cumulus and the microphysics processes. The analysis is made at the seasonal time scale and focuses on mean values and interannual variability of temperature and precipitation. The objectives are (1) to evaluate and characterize differences among the simulations attributable to changes in the physical options of the regional model, and (2) to identify the most suitable parametrization schemes and understand the underlying mechanisms causing that some schemes perform better than others. The results confirm the paramount importance of the model physics, showing that the spread among the various simulations is of comparable magnitude to the spread obtained in similar multi-model ensembles. This suggests that most of the spread obtained in multi-model ensembles could be attributable to the different physical configurations employed in the various models. Second, we obtain that no single ensemble member outperforms the others in every situation. Nevertheless, some particular schemes display a better performance. On the one hand, the non-local MRF PBL scheme reduces the cold bias of the simulations throughout the year compared to the local Eta model. The reason is that the former simulates deeper mixing layers. On the other hand, the Grell parametrization scheme for cumulus produces smaller amount of precipitation in the summer season compared to the more complex Kain-Fritsch scheme by reducing the overestimation in the simulated frequency of the convective precipitation events. Consequently, the interannual variability of precipitation (temperature

  3. The role of packaging size on contamination rates during simulated presentation to a sterile field.

    PubMed

    Trier, Tony; Bello, Nora; Bush, Tamara Reid; Bix, Laura

    2014-01-01

    The objective of this study was to assess the impact of package size on the contact between medical devices and non-sterile surfaces (i.e. the hands of the practitioner and the outside of the package) during aseptic presentation to a simulated sterile field. Rationale for this objective stems from the decades-long problem of hospital-acquired infections. This work approaches the problem from a unique perspective, namely packaging size. Randomized complete block design with subsampling. Research study conducted at professional conferences for surgical technologists and nursing professionals. Ninety-seven healthcare providers, primarily surgical technologists and nurses. Participants were gloved and asked to present the contents of six pouches of three different sizes to a simulated sterile field. The exterior of pouches and gloves of participants were coated with a simulated contaminant prior to each opening trial. After presentation to the simulated sterile field, the presence of the contaminant on package contents was recorded as indicative of contact with non-sterile surfaces and analyzed in a binary fashion using a generalized linear mixed model. Recruited subjects were 26-64 years of age (81 females, 16 males), with 2.5-44 years of professional experience. Results indicated a significant main effect of pouch size on contact rate of package contents (P = 0.0108), whereby larger pouches induced greater rates of contact than smaller pouches (estimates±SEM: 14.7±2.9% vs. 6.0±1.7%, respectively). This study utilized novel methodologies which simulate contamination in aseptic presentation. Results of this work indicate that increased contamination rates are associated with larger pouches when compared to smaller pouches. The results add to a growing body of research which investigate packaging's role in serving as a pathway for product contamination during aseptic presentation. Future work should investigate other packaging design factors (e.g. material

  4. Sea level rise over the Mediterranean: present climate and scenario Simulations

    NASA Astrophysics Data System (ADS)

    Dell'Aquila, A.; Calmanti, S.; Carillo, A.; Rupolo, V.; Ruti, Pm; Sannino, G.; Artale, V.

    2010-09-01

    A regional atmosphere-ocean coupled model (the PROTHEUS system) has been used to estimate sea level rise in the Mediterranean basin. A present climate simulation has been forced by ERA40 covering the period 1958-2001. Another simulation has been forced by the coupled model ECHAM5-MPIOM for the period 1951-2000 and under the scenario SRES A1B for the period 2001-2050. The present climate simulation has been verified in terms of temperature and salinity against observed data, showing good performances both in the mean values and in the variability. Halosteric and thermosteric components have been computed and the total steric sea level has been compared with satellite data. The comparison with altimeter data has been done for the whole Mediterranean and for sub-basins, the capability of the system to reproduce the inter-annual variability of the sea level has been verified. Data from the scenario simulation have been used to evaluate long term trends for the XX and XXI centuries. The modelling tools presented in this work, developed in the framework of CIRCE EU Project RL2 will also contribute to the Med-CORDEX activities.

  5. Adjustment of mean velocity and turbulence due to a finite-size wind farm in a neutral ABL - A LES study

    NASA Astrophysics Data System (ADS)

    Sharma, Varun; Parlange, Marc B.; Calaf, Marc

    2015-11-01

    Large-eddy simulation (LES) has become a well-established tool to simulate and understand the interaction between wind farms and the atmospheric boundary layer (ABL). A popular simulation technique considers wind turbines as actuator disks and simulates `infinite' wind farms due to periodic boundary conditions in the horizontal directions. These simulations have indicated the presence of a fully developed internal boundary layer (IBL) due to `wind farm roughness', which has been shown to have important implications, especially in stratified flow conditions. However, the relationship between the length of the wind farm and the resulting IBL vis-à-vis the asymptotic IBL and its relevance in real-world wind farms is not well understood at present. To address this issue, simulations of wind farms with different horizontal extents are performed in a neutral ABL using an extremely elongated computational domain. Results focus on identifying length scales defining the adjustment of the ABL to a new equilibrium within the wind farm and comparing it to the infinite wind farm case. Furthermore, analyses shall be extended upstream as well as downstream of the wind farm to determine the `impact' region and the `exit' region of the wind farm.

  6. Sea level rise over the Mediterranean: present climate and scenario simulations

    NASA Astrophysics Data System (ADS)

    Carillo, Adriana; Ruti, Paolo Michele; Rupolo, Volfango; Sannino, Gianmaria; Calmanti, Sandro; Dell'Aquila, Alessandro; Artale, Vincenzo

    2010-05-01

    A regional atmosphere-ocean coupled model (the Protheus system) has been used to estimate sea level rise in the Mediterranean basin. A present climate simulation has been forced by ERA40 covering the period 1958-2001. Another simulation has been forced by the coupled model ECHAM5-MPIOM for the period 1951-2000 and under the scenario SRES A1B for the period 2001-2050. The present climate simulation has been verified in terms of temperature and salinity against observed data, showing good performances both in the mean values and in the variability. Halosteric and thermosteric components have been computed and the total steric sea level has been compared with satellite data. The comparison with altimeter data has been done for the whole Mediterranean and for sub-basins, the capability of the system to reproduce the inter-annual variability of the sea level has been verified. Data from the scenario simulation have been used to evaluate long term trends for the XX and XXI centuries.

  7. Farm Animals

    MedlinePlus

    ... the Back of a Horse Chickens in the City Diseases Cat-Scratch Disease E. coli Infection Ringworm ... animals when even when they appear healthy and clean. Although it usually doesn’t make farm animals ...

  8. MELODIE: a whole-farm model to study the dynamics of nutrients in dairy and pig farms with crops.

    PubMed

    Chardon, X; Rigolot, C; Baratte, C; Espagnol, S; Raison, C; Martin-Clouaire, R; Rellier, J-P; Le Gall, A; Dourmad, J Y; Piquemal, B; Leterme, P; Paillat, J M; Delaby, L; Garcia, F; Peyraud, J L; Poupa, J C; Morvan, T; Faverdin, P

    2012-10-01

    In regions of intensive pig and dairy farming, nutrient losses to the environment at farm level are a source of concern for water and air quality. Dynamic models are useful tools to evaluate the effects of production strategies on nutrient flows and losses to the environment. This paper presents the development of a new whole-farm model upscaling dynamic models developed at the field or animal scale. The model, called MELODIE, is based on an original structure with interacting biotechnical and decisional modules. Indeed, it is supported by an ontology of production systems and the associated programming platform DIESE. The biotechnical module simulates the nutrient flows in the different animal, soil and crops and manure sub-models. The decision module relies on an annual optimization of cropping and spreading allocation plans, and on the flexible execution of activity plans for each simulated year. These plans are examined every day by an operational management sub-model and their application is context dependent. As a result, MELODIE dynamically simulates the flows of carbon, nitrogen, phosphorus, copper, zinc and water within the whole farm over the short and long-term considering both the farming system and its adaptation to climatic conditions. Therefore, it is possible to study both the spatial and temporal heterogeneity of the environmental risks, and to test changes of practices and innovative scenarios. This is illustrated with one example of simulation plan on dairy farms to interpret the Nitrogen farm-gate budget indicator. It shows that this indicator is able to reflect small differences in Nitrogen losses between different systems, but it can only be interpreted using a mobile average, not on a yearly basis. This example illustrates how MELODIE could be used to study the dynamic behaviour of the system and the dynamic of nutrient flows. Finally, MELODIE can also be used for comprehensive multi-criterion assessments, and it also constitutes a generic

  9. Present-day Circum-Antarctic Simulations using the POPSICLES Coupled Ice Sheet-Ocean Model

    NASA Astrophysics Data System (ADS)

    Asay-Davis, X.; Martin, D. F.; Price, S. F.; Maltrud, M. E.; Collins, W.

    2014-12-01

    We present POPSICLES simulation results covering the full Antarctic Ice Sheet and the Southern Ocean spanning the period 1990 to 2010. Simulations are performed at 0.1o (~5 km) ocean resolution and with adaptive ice-sheet model resolution as fine as 500 m. We compare time-averaged melt rates below a number of major ice shelves with those reported by Rignot et al. (2013) as well as other recent studies. We also present seasonal variability and decadal trends in submarine melting from several Antarctic regions. Finally, we explore the influence on basal melting and system dynamics resulting from two different choices of climate forcing: a "normal-year" climatology and the CORE v. 2 forcing data (Large and Yeager 2008).POPSICLES couples the POP2x ocean model, a modified version of the Parallel Ocean Program (Smith and Gent, 2002), and the BISICLES ice-sheet model (Cornford et al., 2012). POP2x includes sub-ice-shelf circulation using partial top cells (Losch, 2008) and boundary layer physics following Holland and Jenkins (1999), Jenkins (2001), and Jenkins et al. (2010). Standalone POP2x output compares well with standard ice-ocean test cases (e.g., ISOMIP; Losch, 2008) and other continental-scale simulations and melt-rate observations (Kimura et al., 2013; Rignot et al., 2013). BISICLES makes use of adaptive mesh refinement and a 1st-order accurate momentum balance similar to the L1L2 model of Schoof and Hindmarsh (2009) to accurately model regions of dynamic complexity, such as ice streams, outlet glaciers, and grounding lines. Results of BISICLES simulations have compared favorably to comparable simulations with a Stokes momentum balance in both idealized tests (MISMIP-3D; Pattyn et al., 2013) and realistic configurations (Favier et al. 2014).A companion presentation, "Response of the Antarctic Ice Sheet to ocean forcing using the POPSICLES coupled ice sheet-ocean model" in session C024 covers the ice-sheet response to these melt rates in the coupled simulation

  10. Effects of Training on Recognition of Musical Instruments Presented through Cochlear Implant Simulations

    PubMed Central

    Driscoll, Virginia D.; Oleson, Jacob; Jiang, Dingfeng; Gfeller, Kate

    2009-01-01

    Background The simulation of the CI (cochlear implant) signal presents a degraded representation of each musical instrument, which makes recognition difficult. Purpose To examine the efficiency and effectiveness of three types of training on recognition of musical instruments as presented through simulations of the sounds transmitted through a CI. Research Design Participants were randomly assigned to one of three training conditions: repeated exposure, feedback, and direct instruction. Study Sample Sixty-six adults with normal hearing. Intervention Each participant completed three training sessions per week, over a five-week time period, in which they listened to the CI simulations of eight different musical instruments. Data Collection and Analysis Analyses on percent of instruments identified correctly showed statistically significant differences between recognition accuracy of the three training conditions (p< .01). Results those assigned to the direct instruction group showed the greatest improvement over the five-week training period as well as sustained improvement after training. The feedback group achieved the next highest level of recognition accuracy. The repeated exposure group showed modest improvement during the first three-week time period, but no subsequent improvements. Conclusions These results indicate that different types of training are differentially effective with regard to improving recognition of musical instruments presented through a degraded signal, which has practical implications for the auditory rehabilitation of persons who use cochlear implants. PMID:19927684

  11. ENSO anomalies over the Western United States: present and future patterns in regional climate simulations

    SciTech Connect

    Zhang, Yongxin; Qian, Yun; Duliere, Valerie; Salathe, E.; Leung, Lai-Yung R.

    2012-01-03

    Surface temperature, precipitation, specific humidity and wind anomalies associated with the warm and cold phases of ENSO simulated by WRF and HadRM are examined for the present and future decades. WRF is driven by ECHAM5 and CCSM3, respectively, and HadRM is driven by HadCM3. For the current decades, all simulations show some capability in resolving the observed warm-dry and coolwet teleconnection patterns over the PNW and the Southwest U.S. for warm and cold ENSO. Differences in the regional simulations originate primarily from the respective driving fields. For the future decades, the warm-dry and cool-wet teleconnection patterns in association with ENSO are still represented in ECHAM5-WRF and HadRM. However, there are indications of changes in the ENSO teleconnection patterns for CCSM3-WRF in the future, with wet anomalies dominating in the PNW and the Southwest U.S. for both warm and cold ENSO, in contrast to the canonical patterns of precipitation anomalies. Interaction of anomalous wind flow with local terrain plays a critical role in the generation of anomalous precipitation over the western U.S. Anomalous dry conditions are always associated with anomalous airflow that runs parallel to local mountains and wet conditions with airflow that runs perpendicular to local mountains. Future changes in temperature and precipitation associated with the ENSO events in the regional simulations indicate varying responses depending on the variables examined as well as depending on the phase of ENSO.

  12. Monte-Carlo background simulations of present and future detectors in x-ray astronomy

    NASA Astrophysics Data System (ADS)

    Tenzer, C.; Kendziorra, E.; Santangelo, A.

    2008-07-01

    Reaching a low-level and well understood internal instrumental background is crucial for the scientific performance of an X-ray detector and, therefore, a main objective of the instrument designers. Monte-Carlo simulations of the physics processes and interactions taking place in a space-based X-ray detector as a result of its orbital environment can be applied to explain the measured background of existing missions. They are thus an excellent tool to predict and optimize the background of future observatories. Weak points of a design and the main sources of the background can be identified and methods to reduce them can be implemented and studied within the simulations. Using the Geant4 Monte-Carlo toolkit, we have created a simulation environment for space-based detectors and we present results of such background simulations for XMM-Newton's EPIC pn-CCD camera. The environment is also currently used to estimate and optimize the background of the future instruments Simbol-X and eRosita.

  13. Analysis of Present Day and Future OH and Methane Lifetime in the ACCMIP Simulations

    NASA Technical Reports Server (NTRS)

    Voulgarakis, A.; Naik, V.; Lamarque, J. -F.; Shindell, D. T.; Young, P. J.; Prather, M. J.; Wild, O.; Field, R. D.; Bergmann, D.; Cameron-Smith P.; Cionni, I; Collins, W. J.; Dalsoren, S. B.; Doherty, R. M.; Eyring, V.; Faluvegi, G.; Folberth, G. A.; Horowitz, L. W.; Josse, B.; MacKenzie, I. A.; Nagashima, T.; Plummer, D. A.; Righi, M.; Rumbold, S. T.; Strode, S. A.

    2013-01-01

    Results from simulations performed for the Atmospheric Chemistry and Climate Modeling Intercomparison Project (ACCMIP) are analysed to examine how OH and methane lifetime may change from present day to the future, under different climate and emissions scenarios. Present day (2000) mean tropospheric chemical lifetime derived from the ACCMIP multi-model mean is 9.8+/-1.6 yr (9.3+/-0.9 yr when only including selected models), lower than a recent observationally-based estimate, but with a similar range to previous multi-model estimates. Future model projections are based on the four Representative Concentration Pathways (RCPs), and the results also exhibit a large range. Decreases in global methane lifetime of 4.5 +/- 9.1% are simulated for the scenario with lowest radiative forcing by 2100 (RCP 2.6), while increases of 8.5+/-10.4% are simulated for the scenario with highest radiative forcing (RCP 8.5). In this scenario, the key driver of the evolution of OH and methane lifetime is methane itself, since its concentration more than doubles by 2100 and it consumes much of the OH that exists in the troposphere. Stratospheric ozone recovery, which drives tropospheric OH decreases through photolysis modifications, also plays a partial role. In the other scenarios, where methane changes are less drastic, the interplay between various competing drivers leads to smaller and more diverse OH and methane lifetime responses, which are difficult to attribute. For all scenarios, regional OH changes are even more variable, with the most robust feature being the large decreases over the remote oceans in RCP8.5. Through a regression analysis, we suggest that differences in emissions of non-methane volatile organic compounds and in the simulation of photolysis rates may be the main factors causing the differences in simulated present day OH and methane lifetime. Diversity in predicted changes between present day and future OH was found to be associated more strongly with differences in

  14. The Role of Packaging Size on Contamination Rates during Simulated Presentation to a Sterile Field

    PubMed Central

    Trier, Tony; Bello, Nora; Bush, Tamara Reid; Bix, Laura

    2014-01-01

    Objective The objective of this study was to assess the impact of package size on the contact between medical devices and non-sterile surfaces (i.e. the hands of the practitioner and the outside of the package) during aseptic presentation to a simulated sterile field. Rationale for this objective stems from the decades-long problem of hospital-acquired infections. This work approaches the problem from a unique perspective, namely packaging size. Design Randomized complete block design with subsampling. Setting Research study conducted at professional conferences for surgical technologists and nursing professionals. Participants Ninety-seven healthcare providers, primarily surgical technologists and nurses. Methods Participants were gloved and asked to present the contents of six pouches of three different sizes to a simulated sterile field. The exterior of pouches and gloves of participants were coated with a simulated contaminant prior to each opening trial. After presentation to the simulated sterile field, the presence of the contaminant on package contents was recorded as indicative of contact with non-sterile surfaces and analyzed in a binary fashion using a generalized linear mixed model. Results Recruited subjects were 26–64 years of age (81 females, 16 males), with 2.5–44 years of professional experience. Results indicated a significant main effect of pouch size on contact rate of package contents (P = 0.0108), whereby larger pouches induced greater rates of contact than smaller pouches (estimates±SEM: 14.7±2.9% vs. 6.0±1.7%, respectively). Discussion and Conclusion This study utilized novel methodologies which simulate contamination in aseptic presentation. Results of this work indicate that increased contamination rates are associated with larger pouches when compared to smaller pouches. The results add to a growing body of research which investigate packaging's role in serving as a pathway for product contamination during aseptic presentation

  15. Analysis of Present Day and Future OH and Methane Lifetime in the ACCMIP Simulations

    NASA Technical Reports Server (NTRS)

    Voulgarakis, A.; Naik, V.; Lamarque, J. -F.; Shindell, D. T.; Young, P. J.; Prather, M. J.; Wild, O.; Field, R. D.; Bergmann, D.; Cameron-Smith P.; hide

    2013-01-01

    Results from simulations performed for the Atmospheric Chemistry and Climate Modeling Intercomparison Project (ACCMIP) are analysed to examine how OH and methane lifetime may change from present day to the future, under different climate and emissions scenarios. Present day (2000) mean tropospheric chemical lifetime derived from the ACCMIP multi-model mean is 9.8+/-1.6 yr (9.3+/-0.9 yr when only including selected models), lower than a recent observationally-based estimate, but with a similar range to previous multi-model estimates. Future model projections are based on the four Representative Concentration Pathways (RCPs), and the results also exhibit a large range. Decreases in global methane lifetime of 4.5 +/- 9.1% are simulated for the scenario with lowest radiative forcing by 2100 (RCP 2.6), while increases of 8.5+/-10.4% are simulated for the scenario with highest radiative forcing (RCP 8.5). In this scenario, the key driver of the evolution of OH and methane lifetime is methane itself, since its concentration more than doubles by 2100 and it consumes much of the OH that exists in the troposphere. Stratospheric ozone recovery, which drives tropospheric OH decreases through photolysis modifications, also plays a partial role. In the other scenarios, where methane changes are less drastic, the interplay between various competing drivers leads to smaller and more diverse OH and methane lifetime responses, which are difficult to attribute. For all scenarios, regional OH changes are even more variable, with the most robust feature being the large decreases over the remote oceans in RCP8.5. Through a regression analysis, we suggest that differences in emissions of non-methane volatile organic compounds and in the simulation of photolysis rates may be the main factors causing the differences in simulated present day OH and methane lifetime. Diversity in predicted changes between present day and future OH was found to be associated more strongly with differences in

  16. Smallholder farms as stepping stone corridors for crop-raiding elephant in northern Tanzania: integration of Bayesian expert system and network simulator.

    PubMed

    Pittiglio, Claudia; Skidmore, Andrew K; van Gils, Hein A M J; McCall, Michael K; Prins, Herbert H T

    2014-03-01

    Crop-raiding elephants affect local livelihoods, undermining conservation efforts. Yet, crop-raiding patterns are poorly understood, making prediction and protection difficult. We hypothesized that raiding elephants use corridors between daytime refuges and farmland. Elephant counts, crop-raiding records, household surveys, Bayesian expert system, and least-cost path simulation were used to predict four alternative categories of daily corridors: (1) footpaths, (2) dry river beds, (3) stepping stones along scattered small farms, and (4) trajectories of shortest distance to refuges. The corridor alignments were compared in terms of their minimum cumulative resistance to elephant movement and related to crop-raiding zones quantified by a kernel density function. The "stepping stone" corridors predicted the crop-raiding patterns. Elephant presence was confirmed along these corridors, demonstrating that small farms located between refuges and contiguous farmland increase habitat connectivity for elephant. Our analysis successfully predicted elephant occurrence in farmland where daytime counts failed to detect nocturnal presence. These results have conservation management implications.

  17. Definition of sanitary boundaries to prevent ISAv spread between salmon farms in southern Chile based on numerical simulations of currents

    NASA Astrophysics Data System (ADS)

    Olivares, Gonzalo; Sepúlveda, H. H.; Yannicelli, B.

    2015-06-01

    The infectious Salmon Anemia virus (ISAv) is a pathogen that mainly affects the Atlantic Salmon (Salmo salar). It was detected in Norway in 1984 and in June 2007 appeared in Chile, producing a drop of more than 30% in the country's production level. It is expected that with certain regularity, outbreaks will continue to appear in Chile without the need of reintroducing the virus from foreign countries. We present a numerical study of the influence of winds and tides in the dispersion of lagrangian particles to simulate the transport of ISAv in the Aysen region, in southern Chile. This study combines the use of numerical models of the ocean and atmosphere, lagrangian tracking and biological aspects of ISAv infections. As in previous results, a wider dispersion of ISAv was observed during spring tides. Temporal changes in wind significantly modified the transport of viral particles from an infected center. Under similar forcing conditions, the areas of risk associated to culture sites separated by a few kilometers could be very different. Our main results remark the importance of the use of a detailed knowledge of hydrographic and atmospheric circulation in the definition of boundaries for sanitary management areas. We suggest that a methodology similar to the one presented in this study should be considered to define sanitary strategies to minimize the occurrence of native outbreaks of ISAv.

  18. Using a whole farm model to determine the impacts of mating management on the profitability of pasture-based dairy farms.

    PubMed

    Beukes, P C; Burke, C R; Levy, G; Tiddy, R M

    2010-08-01

    An approach to assessing likely impacts of altering reproductive performance on productivity and profitability in pasture-based dairy farms is described. The basis is the development of a whole farm model (WFM) that simulates the entire farm system and holistically links multiple physical performance factors to profitability. The WFM consists of a framework that links a mechanistic cow model, a pasture model, a crop model, management policies and climate. It simulates individual cows and paddocks, and runs on a day time-step. The WFM was upgraded to include reproductive modeling capability using reference tables and empirical equations describing published relationships between cow factors, physiology and mating management. It predicts reproductive status at any time point for individual cows within a modeled herd. The performance of six commercial pasture-based dairy farms was simulated for the period of 12 months beginning 1 June 2005 (05/06 year) to evaluate the accuracy of the model by comparison with actual outcomes. The model predicted most key performance indicators within an acceptable range of error (residual<10% of observed). The evaluated WFM was then used for the six farms to estimate the profitability of changes in farm "set-up" (farm conditions at the start of the farming year on 1 June) and mating management from 05/06 to 06/07 year. Among the six farms simulated, the 4-week calving rate emerged as an important set-up factor influencing profitability, while reproductive performance during natural bull mating was identified as an area with the greatest opportunity for improvement. The WFM presents utility to explore alternative management strategies to predict likely outcomes to proposed changes to a pasture-based farm system.

  19. Simulation of salinity effects on past, present, and future soil organic carbon stocks.

    PubMed

    Setia, Raj; Smith, Pete; Marschner, Petra; Gottschalk, Pia; Baldock, Jeff; Verma, Vipan; Setia, Deepika; Smith, Jo

    2012-02-07

    Soil organic carbon (SOC) models are used to predict changes in SOC stocks and carbon dioxide (CO(2)) emissions from soils, and have been successfully validated for non-saline soils. However, SOC models have not been developed to simulate SOC turnover in saline soils. Due to the large extent of salt-affected areas in the world, it is important to correctly predict SOC dynamics in salt-affected soils. To close this knowledge gap, we modified the Rothamsted Carbon Model (RothC) to simulate SOC turnover in salt-affected soils, using data from non-salt-affected and salt-affected soils in two agricultural regions in India (120 soils) and in Australia (160 soils). Recently we developed a decomposition rate modifier based on an incubation study of a subset of these soils. In the present study, we introduce a new method to estimate the past losses of SOC due to salinity and show how salinity affects future SOC stocks on a regional scale. Because salinity decreases decomposition rates, simulations using the decomposition rate modifier for salinity suggest an accumulation of SOC. However, if the plant inputs are also adjusted to reflect reduced plant growth under saline conditions, the simulations show a significant loss of soil carbon in the past due to salinization, with a higher average loss of SOC in Australian soils (55 t C ha(-1)) than in Indian soils (31 t C ha(-1)). There was a significant negative correlation (p < 0.05) between SOC loss and osmotic potential. Simulations of future SOC stocks with the decomposition rate modifier and the plant input modifier indicate a greater decrease in SOC in saline than in non-saline soils under future climate. The simulations of past losses of SOC due to salinity were repeated using either measured charcoal-C or the inert organic matter predicted by the Falloon et al. equation to determine how much deviation from the Falloon et al. equation affects the amount of plant inputs generated by the model for the soils used in this study

  20. Field tests and modelling of a wind farm with doubly fed induction generators

    NASA Astrophysics Data System (ADS)

    Meisingset, Magne; Ohnstad, Trond M.; Uhlen, Kjetil; Strand, Leif R.

    2005-07-01

    Havøygavlen is Norway's second wind farm and started operation in 2002. Several new wind farms are currently under planning at various sites along the Norwegian coast. The Norwegian transmission system operator (TSO) Statnett SF and Sintef Energy Research have jointly developed a dynamic simulation model for Havøygavlen in order to analyse the interaction between wind farms and the transmission grid. Full-scale field tests have been conducted to investigate the dynamic behaviour of the wind farm and to verify the model by comparing simulations with measurements. This article presents results from the field tests, model validation work as well as operating experiences for Havøygavlen wind farm. Copyright

  1. Dynamic response improvement of doubly fed induction generator-based wind farm using fuzzy logic controller

    NASA Astrophysics Data System (ADS)

    Hasanien, Hany M.; Al-Ammar, Essam A.

    2012-11-01

    Doubly fed induction generator (DFIG) based wind farm is today the most widely used concept. This paper presents dynamic response enhancement of DFIG based wind farm under remote fault conditions using the fuzzy logic controller. The goal of the work is to improve the dynamic response of DFIG based wind farm during and after the clearance of fault using the proposed controller. The stability of wind farm during and after the clearance of fault is investigated. The effectiveness of the fuzzy logic controller is then compared with that of a PI controller. The validity of the controllers in restoring the wind farms normal operation after the clearance of fault is illustrated by the simulation results which are carried out using MATLAB/SIMULINK. Simulation results are analyzed under different fault conditions.

  2. Factitious Disorder Presenting with Attempted Simulation of Fournier’s Gangrene

    PubMed Central

    Tseng, Joseph; Poullos, Peter

    2016-01-01

    Fournier’s gangrene is a severe polymicrobial necrotizing fasciitis of the perineal, genital, or perianal regions. The classic presentation is severe pain and swelling with systemic signs. Crepitus and cutaneous necrosis are often seen. Characteristic CT findings include subcutaneous gas and inflammatory stranding. Unless treated aggressively, patients can rapidly become septic and die. Factitious Disorder is the falsification of one’s own of medical or psychological signs and symptoms. Many deceptive methods have been described, from falsely reporting physical or psychological symptoms, to manipulating lab tests, or even injecting or ingesting foreign substances in order to induce illness. We present a case of a 35-year-old man with factitious disorder who attempted to simulate Fournier’s gangrene by injecting his scrotum with air and fluid. We will review the clinical presentation and diagnosis of Factitious Disorder, as well as Fournier’s gangrene. PMID:27761196

  3. Farmed Atlantic salmon: potential invader in the Pacific Northwest?

    Treesearch

    Jonathan Thompson; Pete Bisson

    2008-01-01

    Commercial farming of Atlantic salmon in marine net-pens has become a booming industry. At present, approximately 130 salmon farms exist along the Pacific coast of North America. Most of these farms are in cold marine bays within British Columbia, where farmed salmon have become the province’s most valuable agricultural export. Each year, thousands of farmed Atlantic...

  4. Farm Simulation: a tool for evaluating the mitigation of greenhouse gas emissions and the adaptation of dairy production to climate change

    USDA-ARS?s Scientific Manuscript database

    Farms both produce greenhouse gas emissions that drive human-induced climate change and are impacted by that climate change. Whole farm and global climate models provide useful tools for studying the benefits and costs of greenhouse gas mitigation and the adaptation of farms to changing climate. The...

  5. Mesoscale Influences of Wind Farms Throughout a Diurnal Cycle

    NASA Astrophysics Data System (ADS)

    Fitch, A. C.; Lundquist, J. K.; Olson, J. B.

    2012-12-01

    Few observations are available to give insight into the interaction between large wind farms and the boundary layer. As wind farm deployment increases, questions are arising on the potential impact on meteorology within and downwind of large wind farms. While large-eddy simulation can provide insight into the detailed interaction between individual turbines and the boundary layer, to date it has been too computationally expensive to simulate wind farms with large numbers of turbines and the resulting wake far downstream. Mesoscale numerical weather prediction models provide the opportunity to investigate the flow in and around large wind farms as a whole, and the resulting impact on meteorology. To this end, we have implemented a wind farm parameterization in the Weather Research and Forecasting (WRF) model, which represents wind turbines by imposing a momentum sink on the mean flow; converting kinetic energy into electricity and turbulent kinetic energy (TKE). The parameterization improves upon previous models, basing the atmospheric drag of turbines on the thrust coefficient of a modern commercial turbine. In addition, the source of TKE varies with wind speed, reflecting the amount of energy extracted from the atmosphere by the turbines that does not produce electrical energy. We simulate a wind farm covering 10x10 km over land, consisting of 100 turbines each of nominal power output of 5 MW. Results will be presented showing how the wake structure varies dramatically over a diurnal cycle characteristic of a region in the Great Plains of the US, where wind farm deployment is planned. At night, a low-level jet forms within the rotor area, which is completely eliminated by energy extraction within the wind farm. The deep stable layer and lack of higher momentum air aloft at this time maximises the wind deficit and the length of the wake. The presentation will discuss the maximum reduction of wind speed within and downwind from the farm, and the wake e

  6. Multimodel ensemble simulations of present and future climates over West Africa: Impacts of vegetation dynamics

    NASA Astrophysics Data System (ADS)

    Erfanian, Amir; Wang, Guiling; Yu, Miao; Anyah, Richard

    2016-09-01

    In this study, we take an ensemble modeling approach using the regional climate model RegCM4.3.4-CLM-CN-DV (RCM) to study the impact of including vegetation dynamics on model performance in simulating present-day climate and on future climate projections over West Africa. The ensemble consists of four global climate models (GCMs) as lateral boundary conditions for the RCM, and simulations with both static and dynamic vegetation are conducted. The results demonstrate substantial sensitivity of the simulated precipitation, evapotranspiration, and soil moisture to vegetation representation. Although including dynamic vegetation in the model eliminates potential inconsistencies between surface climate and the bioclimatic requirements of the prescribed vegetation, it enhances model biases causing climate drift. For present-day climate, the ensemble average generally outperforms individual members due to cancelation of model biases. For future changes, although the original GCMs project contradicting future rainfall trends over West Africa, the RCMs-produced trends are generally consistent. The multimodel ensemble projects significant decreases of rainfall over a major portion of West Africa and significant increases over eastern Sahel and East Africa. Projected future changes of evapotranspiration and soil moisture are consistent with those of precipitation, with significant decreases (increases) for western (eastern) Sahel. Accounting for vegetation-climate interactions has localized but significant impacts on projected future changes of precipitation, with a wet signal over a belt of projected increase of woody vegetation cover; the impact on the projected future changes of evapotranspiration and soil moisture over west and central Africa is much more profound.

  7. Stability analysis of offshore wind farm and marine current farm

    NASA Astrophysics Data System (ADS)

    Shawon, Mohammad Hasanuzzaman

    Renewable energy has been playing an important role to meet power demand and 'Green Energy' market is getting bigger platform all over the world in the last few years. Due to massive increase in the prices of fossil fuels along with global warming issues, energy harvesting from renewable energy sources has received considerable interest, nowadays, where extensive researches are going on to ensure optimum use of renewable sources. In order to meet the increasing demand of electricity and power, integration of renewable energy is getting highest priorities around the world. Wind is one of the most top growing renewable energy resources and wind power market penetration is expected to reach 3.35 percent by 2013 from its present market of about 240 GW. A wind energy system is the most environmental friendly, cost effective and safe among all renewable energy resources available. Another promising form of renewable energy is ocean energy which covers 70 % of the earth. Ocean energy can be tapped from waves, tides and thermal elements. Offshore Wind farm (OWF) has already become very popular for large scale wind power integration with the onshore grid. Recently, marine current farm (MCF) is also showing good potential to become mainstream energy sources and already successfully commissioned in United Kingdom. However, squirrel cage induction generator (SCIG) has the stability problem similar to synchronous generator especially during fault location to restore the electromagnetic torque. Series dynamic braking resistor (SDBR) has been known as a useful mean to stabilize fixed speed wind generator system. On the other hand, doubly fed induction generator (DFIG) has the capability of coupling the control of active and reactive power and to provide necessary reactive power demand during grid fault conditions. Series dynamic braking resistor (SDBR) can also be employed with DFIG to limit the rotor over current. An integration of wind and tidal energy represents a new

  8. Farm Equipment

    NASA Astrophysics Data System (ADS)

    1980-01-01

    In production of tractor and a line of farm vehicles, Deere and Company used a COSMIC computer program called FEATS for Finite Element Analysis of Thermal Stress in computer analysis of diesel engine pistons, connecting rods and rocker arms. Company reports that use of FEATS afforded considerable savings and improved analytical accuracies, process efficiencies and product reliability.

  9. Impact Wind Farms on the Marine Atmospheric Boundary Layer

    NASA Astrophysics Data System (ADS)

    Volker, P.; Capps, S. B.; Huang, H. J.; Sun, F.; Badger, J.; Hahmann, A.

    2012-12-01

    We introduce a new, validated wind farm parametrization (Explicit Wake Parametrization, EWP) which is based on the assumption that the downstream propagation of a single turbine wake can be described by a turbulent diffusion process. Thus, the downstream velocity deficit distribution can be described explicitly. Additionally, it allows us to take into account turbine interactions, making it possible to determine the unresolved turbine hub height velocities. Both the EWP wind farm parametrization and the wind farm scheme available in the Weather Research & Forecasting Model (WRF) have been validated against in situ measurements from Horns Rev I (A large offshore wind farm consisting of 80 2MW turbines situated near the west coast of Denmark). The main quantities of interest are the thrust applied to the flow, a consequence of the energy extracted by the wind turbines which determines mainly the wind farm wake extension (around 50 km for Horns Rev I) and the vertical velocity deficit distribution. Results show that the thrust in the WRF-WF scheme is overestimated inside the wind farm. We noticed that the velocity deficit propagates from the first turbine-containing-grid-cell up to the boundary layer top, which is in contrast to the theoretical expected expansion (confirmed by turbulence resolving models and wind tunnel results). The vertical expansion of the velocity deficit is a consequence of the additional turbulence source term in the WRF-WF scheme. The EWP scheme estimates the total amount of thrust correctly and is also able to follow the reduced thrust downstream since it considers the turbine interaction. From the good agreement with the far wake measurement, we can conclude that the formulation of the sub grid scale vertical extension of the velocity deficit must be correct. We will present results from WRF simulations in which we analyze the atmospheric response within the wake of wind farms resulting from the energy extraction of wind turbines. We place

  10. Simulation of heating by optical absorption in nanoparticle dispersions (Conference Presentation)

    NASA Astrophysics Data System (ADS)

    Olbricht, Benjamin C.

    2017-02-01

    With the proliferation of highly confined, nanophotonic waveguides and laser sources with increasing intensity, the effects of laser heating will begin to greatly impact the materials used in optical applications. In order to better understand the mechanism of laser heating, its timescales, and the dispersion of heat into the material, simulations of nanoparticles in various media are presented. A generic model to describe a variety of nanoparticle shapes and sizes is desirable to describe complex phenomenon. These particles are dispersed into various solids, liquids, or gases depending on the application. To simulate nanoparticles and their interaction with their host material, the Finite Element Method (FEM) is used. Heat transfer following an absorption event is also described by a parabolic partial differential equation, and transient solutions are generated in response to continuous, pulsed, or modulated laser radiation. The simplest physical system described by FEM is that of a broadly-absorbing round-shaped nanoparticle dispersed in viscous host fluid or solid. Many experimental and theoretical studies conveniently describe a very similar system: a carbon "black" nanoparticle suspended in water. This material is well-known to exhibit nonlinear behavior when a laser pulse carrying 0.7 J/cm2 is incident on the material. For this process the FEM simulations agree with experimental results to show that a pulse of this fluence is capable of heating the solvent elements adjacent to the nanoparticle to their boiling point. This creates nonlinear scattering which is empirically observed as a nonlinear decrease in the transmitted power at this input fluence.

  11. INACSL Standards of Best Practice for Simulation: Past, Present, and Future.

    PubMed

    Sittner, Barbara J; Aebersold, Michelle L; Paige, Jane B; Graham, Leslie L M; Schram, Andrea Parsons; Decker, Sharon I; Lioce, Lori

    2015-01-01

    To describe the historical evolution of the International Nursing Association for Clinical Simulation and Learning's (INACSL) Standards of Best Practice: Simulation. The establishment of simulation standards began as a concerted effort by the INACSL Board of Directors in 2010 to provide best practices to design, conduct, and evaluate simulation activities in order to advance the science of simulation as a teaching methodology. A comprehensive review of the evolution of INACSL Standards of Best Practice: Simulation was conducted using journal publications, the INACSL website, INACSL member survey, and reports from members of the INACSL Standards Committee. The initial seven standards, published in 2011, were reviewed and revised in 2013. Two new standards were published in 2015. The standards will continue to evolve as the science of simulation advances. As the use of simulation-based experiences increases, the INACSL Standards of Best Practice: Simulation are foundational to standardizing language, behaviors, and curricular design for facilitators and learners.

  12. Using ISSM to Simulate the LIA to Present Ice Margin Change at Upernavik Glacier, Greenland

    NASA Astrophysics Data System (ADS)

    Haubner, K.; Larour, E. Y.; Box, J.; Schlegel, N.; Larsen, S. H.; Kjeldsen, K. K.; Kjaer, K. H.

    2015-12-01

    The possibility for rapid melting of the Greenland ice sheet ranks among the most serious societal climate threats. This project puts the rate of contemporary climate change-driven Greenland ice mass change in a temporal context, by simulating the Greenland ice sheet margin throughout the Holocene and comparing the results with past ice margin positions (e.g. Andresen et al., 2014; Bjørk et al., 2012) and records of glacier activity based on fjord sediment strata (Andresen et al. 2012). Here we show first steps to achieve this goal and model the evolution of the Upernavik Isstrøm, a set of marine-terminating glaciers in Northwest Greenland, during the 20thcentury, using the Ice Sheet System Model (ISSM) (Larour et. al 2012). The simulation runs from 1900, shortly after the Little Ice Age (LIA), to year 2013, initialized using trimline data marking the former extent of the ice sheet and forced by a surface mass balance reconstruction after Box (2013). We address uncertainties in ice front positions and thickness by comparing our simulation output with present ice margin positions in the area. Finally, we investigate the possibility of simulating historic changes at ice sheet margins with this finite element ice sheet model. Andresen, C. S., Kjeldsen, K. K., Harden, B., Nørgaard-Pedersen, N. and Kjær, K. H. 2014. Outlet glacier dynamics and bathymetry at Upernavik Isstrøm and Upernavik Isfjord, North-West Greenland. GEUS Bulletin 31 Andresen, C. S., Straneo, F., Ribergaard, M. H., Bjørk, A. A., Andersen, T.J., Kuijpers, A., Nørgaard-Pedersen, N., Kjær, K. H., Schjøth, F., Weckström, K. and Ahlstrøm, A. P. 2012: Rapid response of Helheim Glacier in Greenland to climate variability over the past century. Nature Geoscience 5 Bjørk, A. A., Kjær, K. H., Korsgaard, N. J., Khan, A., S., Kjeldsen, K. K., Andresen, C. S., Box, J. E., Larsen, N. K. and Funder, S. 2012. Historical aerial photographs uncover eighty years of ice-climate interaction in southeast

  13. Evaluation of a linear washout for simulator motion cue presentation during landing approach

    NASA Technical Reports Server (NTRS)

    Parrish, R. V.; Martin, D. J., Jr.

    1975-01-01

    The comparison of a fixed-base versus a five-degree-of-freedom motion base simulation of a 737 conventional take-off and landing (CTOL) aircraft performing instrument landing system (ILS) landing approaches was used to evaluate a linear motion washout technique. The fact that the pilots felt that the addition of motion increased the pilot workload and this increase was not reflected in the objective data results, indicates that motion cues, as presented, are not a contributing factor to root-mean-square (rms) performance during the landing approach task. Subjective results from standard maneuvering about straight-and-level flight for specific motion cue evaluation revealed that the longitudinal channels (pitch and surge) possibly the yaw channel produce acceptable motions. The roll cue representation, involving both roll and sway channels, was found to be inadequate for large roll inputs, as used for example, in turn entries.

  14. Information Presentation and Control in a Modern Air Traffic Control Tower Simulator

    NASA Technical Reports Server (NTRS)

    Haines, Richard F.; Doubek, Sharon; Rabin, Boris; Harke, Stanton

    1996-01-01

    The proper presentation and management of information in America's largest and busiest (Level V) air traffic control towers calls for an in-depth understanding of many different human-computer considerations: user interface design for graphical, radar, and text; manual and automated data input hardware; information/display output technology; reconfigurable workstations; workload assessment; and many other related subjects. This paper discusses these subjects in the context of the Surface Development and Test Facility (SDTF) currently under construction at NASA's Ames Research Center, a full scale, multi-manned, air traffic control simulator which will provide the "look and feel" of an actual airport tower cab. Special emphasis will be given to the human-computer interfaces required for the different kinds of information displayed at the various controller and supervisory positions and to the computer-aided design (CAD) and other analytic, computer-based tools used to develop the facility.

  15. Farm accidents in children.

    PubMed

    Cameron, D; Bishop, C; Sibert, J R

    1992-07-04

    To examine the problem of accidental injury to children on farms. Prospective county based study of children presenting to accident and emergency departments over 12 months with injuries sustained in a farm setting and nationwide review of fatal childhood farm accidents over the four years April 1986 to March 1990. Accident and emergency departments in Aberystwyth, Carmarthen, Haverfordwest, and Llanelli and fatal accidents in England, Scotland, and Wales notified to the Health and Safety Executive register. Children aged under 16. Death or injury after farm related accidents. 65 accidents were recorded, including 18 fractures. Nine accidents necessitated admission to hospital for a mean of two (range one to four) days. 13 incidents were related to tractors and other machinery; 24 were due to falls. None of these incidents were reported under the statutory notification scheme. 33 deaths were notified, eight related to tractors and allied machinery and 10 related to falling objects. Although safety is improving, the farm remains a dangerous environment for children. Enforcement of existing safety legislation with significant penalties and targeting of safety education will help reduce accident rates further.

  16. Rigorous simulation of OCT image formation using Maxwell's equations in three dimensions (Conference Presentation)

    NASA Astrophysics Data System (ADS)

    Munro, Peter R. T.; Curatolo, Andrea; Sampson, David D.

    2016-03-01

    Existing models of image formation in optical coherence tomography are based upon the extended Huygens-Fresnel formalism. These models all, to varying degrees, rely on scatterer ensemble averages, rather than deterministic scattering distributions. Whilst the former is sometimes preferable, there are a growing number of applications where the ability to predict image formation based upon deterministic refractive index distributions is of great interest, including, for example, image formation in turbid tissue. A rigorous model based upon three-dimensional solutions of Maxwell's equations offers a number of tantalising opportunities. For example, shedding light on features near or below the resolution of an OCT system and on the impact of phenomena usually described as diffraction, interference and scattering, but which more generally result from light scattering satisfying Maxwell's equations. A rigorous model allows inverse scattering methods to be developed not requiring the first-order Born approximation. Finally, a rigorous model can provide gold standard verification of myriad quantitative techniques currently being developed throughout the field. We have developed the first such model of image formation based upon three-dimensional solutions of Maxwell's equations, which has vastly different properties to models based on two-dimensional solutions. Although we present simulated B-scans, this model is equally applicable to C-scans. This has been made possible by advances in computational techniques and in computational resources routinely available. We will present the main features of our model, comparisons of measured and simulated image formation for phantoms and discuss the future of rigorous modelling in optical coherence tomography research and application.

  17. Multi Dark Lens Simulations: weak lensing light-cones and data base presentation

    NASA Astrophysics Data System (ADS)

    Giocoli, Carlo; Jullo, Eric; Metcalf, R. Benton; de la Torre, Sylvain; Yepes, Gustavo; Prada, Francisco; Comparat, Johan; Göttlober, Stefan; Kyplin, Anatoly; Kneib, Jean-Paul; Petkova, Margarita; Shan, Huan Yuan; Tessore, Nicolas

    2016-09-01

    In this paper we present a large data base of weak lensing light cones constructed using different snapshots from the Big MultiDark simulation (BigMDPL). The ray-tracing through different multiple plane has been performed with the GLAMER code accounting both for single source redshifts and for sources distributed along the cosmic time. This first paper presents weak lensing forecasts and results according to the geometry of the VIPERS-W1 and VIPERS-W4 field of view. Additional fields will be available on our data base and new ones can be run upon request. Our data base also contains some tools for lensing analysis. In this paper we present results for convergence power spectra, one point and high order weak lensing statistics useful for forecasts and for cosmological studies. Covariance matrices have also been computed for the different realizations of the W1 and W4 fields. In addition we compute also galaxy-shear and projected density contrasts for different halo masses at two lens redshift according to the CFHTLS source redshift distribution both using stacking and cross-correlation techniques, finding very good agreement.

  18. Simulating crop yield losses in Switzerland for historical and present Tambora climate scenarios

    NASA Astrophysics Data System (ADS)

    Flückiger, Simon; Brönnimann, Stefan; Holzkämper, Annelie; Fuhrer, Jürg; Krämer, Daniel; Pfister, Christian; Rohr, Christian

    2017-07-01

    Severe climatic anomalies in summer 1816, partly due to the eruption of Tambora in April 1815, contributed to delayed growth and poor harvests of important crops in Central Europe. Coinciding with adverse socio-economic conditions, this event triggered the last subsistence crisis in the western World. Here, we model reductions in potential crop yields for 1816 and 1817 and address the question, what impact a similar climatic anomaly would have today. We reconstructed daily weather for Switzerland for 1816/17 on a 2 km grid using historical observations and an analogue resampling method. These data were used to simulate potential crop yields for potato, grain maize, and winter barley using the CropSyst model calibrated for current crop cultivars. We also simulated yields for the same weather anomalies, but referenced to a present-day baseline temperature. Results show that reduced temperature delayed growth and harvest considerably, and in combination with reduced solar irradiance led to a substantial reduction (20%-50%) in the potential yield of potato in 1816. Effects on winter barley were smaller. Significant reductions were also modelled for 1817 and were mainly due to a cold late spring. Relative reductions for the present-day scenario for the two crops were almost indistinguishable from the historical ones. An even stronger response was found for maize, which was not yet common in 1816/17. Waterlogging, which we assessed using a stress-day approach, likely added to the simulated reductions. The documented, strong east-west gradient in malnutrition across Switzerland in 1817/18 could not be explained by biophysical yield limitations (though excess-water limitation might have contributed), but rather by economic, political and social factors. This highlights the importance of these factors for a societies’ ability to cope with extreme climate events. While the adaptive capacity of today’s society in Switzerland is much greater than in the early 19th century

  19. Modelling Farm Animal Welfare

    PubMed Central

    Collins, Lisa M.; Part, Chérie E.

    2013-01-01

    Simple Summary In this review paper we discuss the different modeling techniques that have been used in animal welfare research to date. We look at what questions they have been used to answer, the advantages and pitfalls of the methods, and how future research can best use these approaches to answer some of the most important upcoming questions in farm animal welfare. Abstract The use of models in the life sciences has greatly expanded in scope and advanced in technique in recent decades. However, the range, type and complexity of models used in farm animal welfare is comparatively poor, despite the great scope for use of modeling in this field of research. In this paper, we review the different modeling approaches used in farm animal welfare science to date, discussing the types of questions they have been used to answer, the merits and problems associated with the method, and possible future applications of each technique. We find that the most frequently published types of model used in farm animal welfare are conceptual and assessment models; two types of model that are frequently (though not exclusively) based on expert opinion. Simulation, optimization, scenario, and systems modeling approaches are rarer in animal welfare, despite being commonly used in other related fields. Finally, common issues such as a lack of quantitative data to parameterize models, and model selection and validation are discussed throughout the review, with possible solutions and alternative approaches suggested. PMID:26487411

  20. Agriculture Education. Farm Machinery.

    ERIC Educational Resources Information Center

    Stuttgart Public Schools, AR.

    This curriculum guide is designed for group instruction of secondary agricultural education students enrolled in one or two semester-long courses in farm machinery. The guide presents units of study in the following areas: (1) small gas engines, (2) job opportunities, (3) tractors, (4) engines, (5) hydraulics, (6) electrical system, (7) combine…

  1. Farming the Sea

    ERIC Educational Resources Information Center

    Morgan, William

    1971-01-01

    Florida has initiated a training program in an entirely new dimension--Sea Farming. Presented is a description of the vocational agriculture program designed to teach propagation, cultivation, harvesting, marketing, and conservation practices related to production of oysters, shrimp, scallops, crabs, and fin fishes. (Editor/GB)

  2. Farming the Sea

    ERIC Educational Resources Information Center

    Morgan, William

    1971-01-01

    Florida has initiated a training program in an entirely new dimension--Sea Farming. Presented is a description of the vocational agriculture program designed to teach propagation, cultivation, harvesting, marketing, and conservation practices related to production of oysters, shrimp, scallops, crabs, and fin fishes. (Editor/GB)

  3. Simulation of present-day precipitation over India using a regional climate model

    NASA Astrophysics Data System (ADS)

    Maurya, Rajesh Kumar Singh; Singh, G. P.

    2016-04-01

    The objective of the present paper is to examine the capability of the regional climate model version 3 (RegCM3) to simulate the annual as well as seasonal precipitation variability over the Indian subcontinent. RegCM3 has been run at 40 km horizontal resolution for the period of 1982-2006 continuously and model results were compared to the observed precipitation datasets of India Meteorological Department (IMD) and CPC Merged Analysis of Precipitation (CMAP). Model evaluation has been done using different statistical methods like mean bias error (MBE), root mean square error, mean percentage error (MPE) and studied the spatial pattern of annual and seasonal variability and trend. Daily precipitation data at 1° × 1° grids of IMD have been used to study observed climatological means (both annual and seasonal), regression trends, interannual and intraseasonal variability over India from 1951 to 2007. The spatial distribution of annual precipitation shows a decreasing trend over west coast of India, central India, hilly region of India and an increasing trend is found over the northwest India, peninsular India and northeast India. The temporal distribution of daily precipitation shows highest rainfall of 18 mm/day in mid July (in composite flood cases only) and 12 mm/day during August (in composite drought cases only). The RegCM3 simulated annual and seasonal precipitation variability is close to the observed IMD and CMAP over all India (AI). During winter and pre-monsoon season, the model has overestimated the mean precipitation while underestimated in summer and post-monsoon season. Overall, annual precipitation showed the deficiency of -22.44 % compared to IMD and -1.41 % compared to CMAP over India. To understand the possible cause of annual and seasonal precipitation biases over India and its six homogeneous regions, the vertical difference (model mines National Centre for Environmental Prediction; NCEP) fields of water vapor mixing ratio (WVMR) and air

  4. Far-infrared and dust properties of present-day galaxies in the EAGLE simulations

    NASA Astrophysics Data System (ADS)

    Camps, Peter; Trayford, James W.; Baes, Maarten; Theuns, Tom; Schaller, Matthieu; Schaye, Joop

    2016-10-01

    The Evolution and Assembly of GaLaxies and their Environments (EAGLE) cosmological simulations reproduce the observed galaxy stellar mass function and many galaxy properties. In this work, we study the dust-related properties of present-day EAGLE galaxies through mock observations in the far-infrared and submm wavelength ranges obtained with the 3D dust radiative transfer code SKIRT. To prepare an EAGLE galaxy for radiative transfer processing, we derive a diffuse dust distribution from the gas particles and we re-sample the star-forming gas particles and the youngest star particles into star-forming regions that are assigned dedicated emission templates. We select a set of redshift-zero EAGLE galaxies that matches the K-band luminosity distribution of the galaxies in the Herschel Reference Survey (HRS), a volume-limited sample of about 300 normal galaxies in the Local Universe. We find overall agreement of the EAGLE dust scaling relations with those observed in the HRS, such as the dust-to-stellar mass ratio versus stellar mass and versus NUV-r colour relations. A discrepancy in the f250/f350 versus f350/f500 submm colour-colour relation implies that part of the simulated dust is insufficiently heated, likely because of limitations in our sub-grid model for star-forming regions. We also investigate the effect of adjusting the metal-to-dust ratio and the covering factor of the photodissociation regions surrounding the star-forming cores. We are able to constrain the important dust-related parameters in our method, informing the calculation of dust attenuation for EAGLE galaxies in the UV and optical domain.

  5. Simulated Impact of Climate Change on Fremont Native American Maize Farming in Utah at the MCA-LIA Transition, ca. 12-14th c. CE

    NASA Astrophysics Data System (ADS)

    Thomson, M. J.; MacDonald, G. M.

    2016-12-01

    We present the results of a computational crop modeling experiment for ancient Fremont Native American Zea mays farming in the Uinta Basin, Utah, at the Medieval Climate Anomaly to Little Ice Age (MCA-LIA) transition, ca. 850-1450 CE. This period coincides with the rapid disappearance of complex Native American cultures from the American Southwest. The crop model (the Environment Policy Impact Calculator, EPIC) was driven by statistically downscaled precipitation, temperature and shortwave radiative flux from the Community Earth System Model Last Millennium Ensemble (CESM LME). We found that maize yield responded to changes in the model-reconstructed temperature and precipitation; and periods of reduced maize yields corresponded to the abandonment of higher elevation Fremont 14C-dated archaeological sites. EPIC produces good agreement between modeled and historically reported maize yields for the 19th century.

  6. Computer simulation is an undervalued tool for genetic analysis: a historical view and presentation of SHIMSHON--a Web-based genetic simulation package.

    PubMed

    Greenberg, David A

    2011-01-01

    Computer simulation methods are under-used tools in genetic analysis because simulation approaches have been portrayed as inferior to analytic methods. Even when simulation is used, its advantages are not fully exploited. Here, I present SHIMSHON, our package of genetic simulation programs that have been developed, tested, used for research, and used to generated data for Genetic Analysis Workshops (GAW). These simulation programs, now web-accessible, can be used by anyone to answer questions about designing and analyzing genetic disease studies for locus identification. This work has three foci: (1) the historical context of SHIMSHON's development, suggesting why simulation has not been more widely used so far. (2) Advantages of simulation: computer simulation helps us to understand how genetic analysis methods work. It has advantages for understanding disease inheritance and methods for gene searches. Furthermore, simulation methods can be used to answer fundamental questions that either cannot be answered by analytical approaches or cannot even be defined until the problems are identified and studied, using simulation. (3) I argue that, because simulation was not accepted, there was a failure to grasp the meaning of some simulation-based studies of linkage. This may have contributed to perceived weaknesses in linkage analysis; weaknesses that did not, in fact, exist. Copyright © 2011 S. Karger AG, Basel.

  7. Computer Simulation Is an Undervalued Tool for Genetic Analysis: A Historical View and Presentation of SHIMSHON – A Web-Based Genetic Simulation Package

    PubMed Central

    Greenberg, David A.

    2011-01-01

    Computer simulation methods are under-used tools in genetic analysis because simulation approaches have been portrayed as inferior to analytic methods. Even when simulation is used, its advantages are not fully exploited. Here, I present SHIMSHON, our package of genetic simulation programs that have been developed, tested, used for research, and used to generated data for Genetic Analysis Workshops (GAW). These simulation programs, now web-accessible, can be used by anyone to answer questions about designing and analyzing genetic disease studies for locus identification. This work has three foci: (1) the historical context of SHIMSHON's development, suggesting why simulation has not been more widely used so far. (2) Advantages of simulation: computer simulation helps us to understand how genetic analysis methods work. It has advantages for understanding disease inheritance and methods for gene searches. Furthermore, simulation methods can be used to answer fundamental questions that either cannot be answered by analytical approaches or cannot even be defined until the problems are identified and studied, using simulation. (3) I argue that, because simulation was not accepted, there was a failure to grasp the meaning of some simulation-based studies of linkage. This may have contributed to perceived weaknesses in linkage analysis; weaknesses that did not, in fact, exist. PMID:22189467

  8. Using ISSM to simulate the LIA to present ice margin change at Upernavik Glacier, Greenland

    NASA Astrophysics Data System (ADS)

    Haubner, Konstanze; Larsen, Signe H.; Box, Jason E.; Andersen, Morten L.; Andresen, Camilla S.; Kjær, Kurt H.; Weidick, Anker

    2015-04-01

    The possibility for rapid melting of the Greenland ice sheet ranks among the most serious societal climate threats. To improve predictions it is useful to know more about past ice volume changes. This project puts the rate of contemporary climate change-driven Greenland ice mass change in a temporal context, by simulating the Greenland ice sheet margin throughout the Holocene. The modelled results can be compared with historical ice positions and with records of past glacier activity (i.e. calving) based on studies of sediment cores from the fjord (Andresen et al. 2012). Another data source of ice margins derives from aerial photography and ice trimline positions (Kjær et al. 2012). Here we present a simulation using the Ice Sheet System Model (ISSM) (Larour et. al 2012) of the Upernavik Isstrøm, a set of NW Greenland marine-terminating glaciers. The simulation runs from year 1840 in the Little Ice Age (LIA) to year 2012, forced by an updated surface mass balance reconstruction after Box (2013). The work establishes a base from which we can model the entire Greenland Ice Sheet. To resolve where model development is needed most, using observations that are iteratively excluded from the simulation, we evaluate the relative importance of each data set on the total uncertainty. We discuss the challenges associated with the general model boundary conditions such as the ice-ocean interaction representation in the model and lacking bathymetrical data. Finally, we address the need for further observations and the perspective of applying the model to other glaciers. works cited: • Andresen, C. S., Straneo, F., Ribergaard, M. H., Bjørk, A. A., Andersen, T.J., Kuijpers, A., Nørgaard-Pedersen, N., Kjær, K. H., Schjøth, F., Weckström, K. and Ahlstrøm, A. P. 2012: Rapid response of Helheim Glacier in Greenland to climate variability over the past century. Nature Geoscience 5, 37-41, doi:10.1038/ngeo1349. • Box, J. E. 2013. Greenland ice sheet mass balance

  9. Temporal and spatial water use on irrigated and nonirrigated pasture-based dairy farms.

    PubMed

    Higham, C D; Horne, D; Singh, R; Kuhn-Sherlock, B; Scarsbrook, M R

    2017-08-01

    Robust information for water use on pasture-based dairy farms is critical to farmers' attempts to use water more efficiently and the improved allocation of freshwater resources to dairy farmers. To quantify the water requirements of dairy farms across regions in a practicable manner, it will be necessary to develop predictive models. The objectives of this study were to compare water use on a group of irrigated and nonirrigated farms, validate existing water use models using the data measured on the group of nonirrigated farms, and modify the model so that it can be used to predict water use on irrigated dairy farms. Water use data were collected on a group of irrigated dairy farms located in the Canterbury, New Zealand, region with the largest area under irrigation. The nonirrigated farms were located in the Manawatu region. The amount of water used for irrigation was almost 52-fold greater than the amount of all other forms of water use combined. There were large differences in measured milking parlor water use, stock drinking water, and leakage rates between the irrigated and nonirrigated farms. As expected, stock drinking water was lower on irrigated dairy farms. Irrigation lowers the dry matter percentage of pasture, ensuring that the amount of water ingested from pasture remains high throughout the year, thereby reducing the demand for drinking water. Leakage rates were different between the 2 groups of farms; 47% of stock drinking water was lost as leakage on nonirrigated farms, whereas leakage on the irrigated farms equated to only 13% of stock drinking water. These differences in leakage were thought to be related to regional differences rather than differences in irrigated versus nonirrigated farms. Existing models developed to predict milking parlor, corrected stock drinking water, and total water use on nonirrigated pasture-based dairy farms in a previous related study were tested on the data measured in the present research. As expected, these models

  10. Performance evaluation of corrosion probes in simulated WVNS tank 8D-2 waste: WVNS tank farm process support

    SciTech Connect

    Elmore, M.R.

    1994-07-01

    Five corrosion probes were received from West Valley Nuclear Services for evaluation in simulated tank 8D-2 3rd-stage sludge wash slurry. The same waste slurry simulated was also used in a series of ongoing corrosion studies assessing the effects of in-tank sludge washing on the integrity of tank 8D-2. Two of the corrosion probes were installed in the coupon corrosion test vessels operating at {approximately}150{degrees}F to compare performance of the probes with that observed by coupon tests conducted in the same vessels. Corrosion rate data calculated from electrical resistance measurements of the corrosion probes were evaluated for this study using two slightly different approaches. One approach uses the total length of exposure of the probe to give a ``time-averaged`` value of the corrosion rate. The other approach uses a shorter period of time (relative to the length of the test) in the calculation of corrosion rate, and is referred to as the ``instantaneous`` rate. The interpretation of the probe data and the implications of corrosion rates calculated with either of these methods are discussed in this report.

  11. Simulation modeling to evaluate the persistence of Mycobacterium avium subsp. paratuberculosis (MAP) on commercial dairy farms in the United States.

    PubMed

    Mitchell, R M; Whitlock, R H; Stehman, S M; Benedictus, A; Chapagain, P P; Grohn, Y T; Schukken, Y H

    2008-03-17

    We developed a series of deterministic mathematical models of Mycobacterium avium subsp. paratuberculosis (MAP) transmission on commercial US dairies. Our models build upon and modify models and assumptions in previous work to better reflect the pathobiology of the disease. Parameter values were obtained from literature for animal turnover in US dairy herds and rates of transition between disease states. The models developed were used to test three hypotheses. (1) Infectious transmission following intervention is relatively insensitive to the presence of high-shedding animals. (2) Vertical and pseudo-vertical transmission increases prevalence of disease but is insufficient to explain persistence following intervention. (3) Transiently shedding young animals might aid persistence. Our simulations indicated that multiple levels of contagiousness among infected adult animals in combination with vertical transmission and MAP shedding in infected young animals explained the maintenance of low-prevalence infections in herds. High relative contagiousness of high-shedding adult animals resulted in these animals serving as the predominant contributor to transmission. This caused elimination of infection in herds using the test-and-cull intervention tested in these simulations. Addition of vertical transmission caused persistence of infection in a moderately complicated model. In the most complex model that allowed age-based contacts, calf-to-calf transmission was required for persistence.

  12. INPRES (intraoperative presentation of surgical planning and simulation results): augmented reality for craniofacial surgery

    NASA Astrophysics Data System (ADS)

    Salb, Tobias; Brief, Jakob; Welzel, Thomas; Giesler, Bjoern; Hassfeld, Steffan; Muehling, Joachim; Dillmann, Ruediger

    2003-05-01

    In this paper we present recent developments and pre-clinical validation results of our approach for augmented reality (AR, for short) in craniofacial surgery. A commercial Sony Glasstron display is used for optical see-through overlay of surgical planning and simulation results with a patient inside the operation room (OR). For the tracking of the glasses, of the patient and of various medical instruments an NDI Polaris system is used as standard solution. A complementary inside-out navigation approach has been realized with a panoramic camera. This device is mounted on the head of the surgeon for tracking of fiducials placed on the walls of the OR. Further tasks described include the calibration of the head-mounted display (HMD), the registration of virtual objects with the real world and the detection of occlusions in the object overlay with help of two miniature CCD cameras. The evaluation of our work took place in the laboratory environment and showed promising results. Future work will concentrate on the optimization of the technical features of the prototype and on the development of a system for everyday clinical use.

  13. Intercomparison of present and future climates simulated by coupled ocean-atmosphere GCMs

    SciTech Connect

    Covey, C; AchutaRao, K M; Lambert, S J

    2000-09-06

    We present an overview of results from the most recent phase of the Coupled Model Intercomparison Project (CMIP). This phase of CMIP has archived output from both unforced (''control run'') and perturbed (1% per year increasing atmospheric carbon dioxide) simulations by 15 modern coupled ocean-atmosphere general circulation models. The models are about equally divided between those employing and those not employing ad hoc flux corrections at the ocean-atmosphere interface. The new generation of non-flux-connected control runs are nearly as stable and agree with observations nearly as well as the flux-corrected models. This development represents significant progress in the state of the art of climate modeling since the Second (1995) Scientific Assessment Report of the Intergovernmental Panel on Climate Change (IPCC; see Gates et al. 1996). From the increasing-CO{sub 2} runs, we find that differences between different models, while substantial, are not as great as would be expected from earlier assessments that relied on equilibrium climate sensitivity.

  14. Building Energy Simulation Test for Existing Homes (BESTEST-EX) (Presentation)

    SciTech Connect

    Judkoff, R.; Neymark, J.; Polly, B.

    2011-12-01

    This presentation discusses the goals of NREL Analysis Accuracy R&D; BESTEST-EX goals; what BESTEST-EX is; how it works; 'Building Physics' cases; 'Building Physics' reference results; 'utility bill calibration' cases; limitations and potential future work. Goals of NREL Analysis Accuracy R&D are: (1) Provide industry with the tools and technical information needed to improve the accuracy and consistency of analysis methods; (2) Reduce the risks associated with purchasing, financing, and selling energy efficiency upgrades; and (3) Enhance software and input collection methods considering impacts on accuracy, cost, and time of energy assessments. BESTEST-EX Goals are: (1) Test software predictions of retrofit energy savings in existing homes; (2) Ensure building physics calculations and utility bill calibration procedures perform up to a minimum standard; and (3) Quantify impact of uncertainties in input audit data and occupant behavior. BESTEST-EX is a repeatable procedure that tests how well audit software predictions compare to the current state of the art in building energy simulation. There is no direct truth standard. However, reference software have been subjected to validation testing, including comparisons with empirical data.

  15. Gateway: A Simulation of Immigration Issues in Past and Present America.

    ERIC Educational Resources Information Center

    Mack, Jay; DeKock, Paul; Yount, Dave

    This simulation allows students to experience how their ancestors felt when they decided to emigrate to this country. The basic activity is a core simulation in which students role-play either an immigrant or an immigration processor at Ellis Island in 1900. The amount of time available determines additional enhancement options offered in the…

  16. Wind Farm Recommendation Report

    SciTech Connect

    John Reisenauer

    2011-05-01

    On April 21, 2011, an Idaho National Laboratory (INL) Land Use Committee meeting was convened to develop a wind farm recommendation for the Executive Council and a list of proposed actions for proceeding with the recommendation. In terms of land use, the INL Land Use Committee unanimously agrees that Site 6 is the preferred location of the alternatives presented for an INL wind farm. However, further studies and resolution to questions raised (stated in this report) by the INL Land Use Committee are needed for the preferred location. Studies include, but are not limited to, wind viability (6 months), bats (2 years), and the visual impact of the wind farm. In addition, cultural resource surveys and consultation (1 month) and the National Environmental Policy Act process (9 to 12 months) need to be completed. Furthermore, there is no documented evidence of developers expressing interest in constructing a small wind farm on INL, nor a specific list of expectations or concessions for which a developer might expect INL to cover the cost. To date, INL assumes the National Environmental Policy Act activities will be paid for by the Department of Energy and INL (the environmental assessment has only received partial funding). However, other concessions also may be expected by developers such as roads, fencing, power line installation, tie-ins to substations, annual maintenance, snow removal, access control, down-time, and remediation. These types of concessions have not been documented, as a request, from a developer and INL has not identified the short and long-term cost liabilities for such concessions should a developer expect INL to cover these costs. INL has not identified a go-no-go funding level or the priority this Wind Farm Project might have with respect to other nuclear-related projects, should the wind farm remain an unfunded mandate. The Land Use Committee recommends Legal be consulted to determine what, if any, liabilities exist with the Wind Farm Project and

  17. Flammable Gas Safety Program: Mechanisms of gas generation from simulated SY Tank Farm wastes. Progress report, FY 1994

    SciTech Connect

    Barefield, E.K.; Boadtright, D.; Deshpande, A.; Doctorovich, F.; Liotta, C.L.; Neumann, H.M.; Seymore, S.

    1995-09-01

    This is the final report for work done at Georgia Tech during Fiscal Year 1994. The objectives of this work were to develop a better understanding of the mechanism of formation of flammable gases in the thermal decomposition of metal complexants, such as HEDTA and sodium glycolate, in simulated SY waste mixtures. This project is a continuation of work begun under earlier contracts with Westinghouse Hanford Co. Three major areas are discussed: development of a reliable analysis for dissolved ammonia, the initiation of long term studies of HEDTA decomposition in stainless steel vessels and product analyses through 3800 h, and further consideration of product analyses and kinetic data reported in FY 1993 for decomposition of HEDTA and sodium glycolate in Teflon-lined glass vessels. A brief exploration was also made of the speciation of aluminum(l1l) in the presence of HEDTA as a function of pH using {sup 27}Al NMR.

  18. [The Iowa Family Farm.

    ERIC Educational Resources Information Center

    Hardesty, Carolyn, Ed.

    1990-01-01

    This issue of the "Goldfinch" focuses on the family farm of the past. All aspects of farm life are covered: what was grown on farms, how the chores were done and who was responsible for them, what the houses were like, and what tools and equipment were used. Comparisons are made between modern farms and farms of 50 or 150 years ago, and…

  19. Wind farms production: Control and prediction

    NASA Astrophysics Data System (ADS)

    El-Fouly, Tarek Hussein Mostafa

    Wind energy resources, unlike dispatchable central station generation, produce power dependable on external irregular source and that is the incident wind speed which does not always blow when electricity is needed. This results in the variability, unpredictability, and uncertainty of wind resources. Therefore, the integration of wind facilities to utility electrical grid presents a major challenge to power system operator. Such integration has significant impact on the optimum power flow, transmission congestion, power quality issues, system stability, load dispatch, and economic analysis. Due to the irregular nature of wind power production, accurate prediction represents the major challenge to power system operators. Therefore, in this thesis two novel models are proposed for wind speed and wind power prediction. One proposed model is dedicated to short-term prediction (one-hour ahead) and the other involves medium term prediction (one-day ahead). The accuracy of the proposed models is revealed by comparing their results with the corresponding values of a reference prediction model referred to as the persistent model. Utility grid operation is not only impacted by the uncertainty of the future production of wind farms, but also by the variability of their current production and how the active and reactive power exchange with the grid is controlled. To address this particular task, a control technique for wind turbines, driven by doubly-fed induction generators (DFIGs), is developed to regulate the terminal voltage by equally sharing the generated/absorbed reactive power between the rotor-side and the gridside converters. To highlight the impact of the new developed technique in reducing the power loss in the generator set, an economic analysis is carried out. Moreover, a new aggregated model for wind farms is proposed that accounts for the irregularity of the incident wind distribution throughout the farm layout. Specifically, this model includes the wake effect

  20. Momentum transfer Monte Carlo model for the simulation of laser speckle contrast imaging (Conference Presentation)

    NASA Astrophysics Data System (ADS)

    Regan, Caitlin; Hayakawa, Carole K.; Choi, Bernard

    2016-03-01

    Laser speckle imaging (LSI) enables measurement of relative blood flow in microvasculature and perfusion in tissues. To determine the impact of tissue optical properties and perfusion dynamics on speckle contrast, we developed a computational simulation of laser speckle contrast imaging. We used a discrete absorption-weighted Monte Carlo simulation to model the transport of light in tissue. We simulated optical excitation of a uniform flat light source and tracked the momentum transfer of photons as they propagated through a simulated tissue geometry. With knowledge of the probability distribution of momentum transfer occurring in various layers of the tissue, we calculated the expected laser speckle contrast arising with coherent excitation using both reflectance and transmission geometries. We simulated light transport in a single homogeneous tissue while independently varying either absorption (.001-100mm^-1), reduced scattering (.1-10mm^-1), or anisotropy (0.05-0.99) over a range of values relevant to blood and commonly imaged tissues. We observed that contrast decreased by 49% with an increase in optical scattering, and observed a 130% increase with absorption (exposure time = 1ms). We also explored how speckle contrast was affected by the depth (0-1mm) and flow speed (0-10mm/s) of a dynamic vascular inclusion. This model of speckle contrast is important to increase our understanding of how parameters such as perfusion dynamics, vessel depth, and tissue optical properties affect laser speckle imaging.

  1. Modelling one row of Horns Rev wind farm with the Actuator Line Model with coarse resolution

    NASA Astrophysics Data System (ADS)

    Draper, M.; Guggeri, A.; Usera, G.

    2016-09-01

    Actuator models have been used to represent the presence of wind turbines in a simulation in the past few years. The Actuator Line Model (ALM) has shown to reproduce with reasonable accuracy the wind flow through wind turbines under different operational conditions. Nevertheless, there are not many simulations of wind farms performed with the ALM mainly because of its computational cost. The aim of the present paper is to evaluate the ALM in spatial resolutions coarser than what is generally recommended, also using larger time steps, in a simulation of a real wind farm. To accomplish this, simulations of one row of Horns Rev wind farm are performed, for different wind directions. It is concluded that the ALM is able to capture the main features of the interaction between wind turbines relaxing its resolution requirements. A sensitivity analysis is performed to assess the influence of the smearing factor and the spatial resolution.

  2. The impact of wakes on power output at large offshore wind farms

    NASA Astrophysics Data System (ADS)

    Barthelmie, R. J.; Frandsen, S.; Hansen, K.; Schepers, G.; Rados, K.; Schlez, W.; Cabezon, D.; Jensen, L.; Neckelmann, S.

    2010-12-01

    The size of planned offshore wind farms is in the range 100 MW to 1 GW requiring tens to hundreds of wind turbines typically arranged in a large array. As wind farms offshore increase in size, one of the research challenges is to model interactions between the individual turbines, the atmosphere and neighbouring turbines to accurately predict power output before wind farm construction in addition to evaluation during the operation phase. The aim of the research described (part of the UpWind project) is to improve wind farm modelling and address the issue of providing more accurate power output predictions accounting for wind turbine wakes. DONG Energy and Vattenfall have allowed data from a number of cases studies to be used in this project. Detailed case studies of power losses due to wakes at the large wind farms at Nysted and Horns Rev have been analysed and are presented. A focus of the data analysis has been to understand the importance of turbulence and atmospheric stability at these offshore sites. It is evident that the magnitude of wake losses is primarily driven by wind speed but that signals from turbine spacing, turbulence and atmospheric stability can be determined. The case studies are simulated with a range of wind farm and computational fluid dynamics (CFD) models. The UpWind project presents a unique platform for model evaluation because the co-operation of a number of groups means that more models can be evaluated on standardised cases. Results shown indicate power losses due to wakes can be modelled, provided that the standard models are subject to some modifications. We also present some of the first full simulations of large offshore wind farms using CFD. Despite this progress, wake modelling of large wind farms is still subject to an unacceptably high degree of uncertainty requiring further work to understand the physical flow processes within and downwind of large wind farms.

  3. Let's put this in perspective: using dynamic simulation modelling to assess the impacts of farm-scale land management change on catchment-scale water quality

    NASA Astrophysics Data System (ADS)

    Rivers, Mark; Clarendon, Simon; Coles, Neil

    2013-04-01

    Natural Resource Management and Agri-industry development groups in Australia have invested considerable resources into the investigation of the economic, social and, particularly, environmental impacts of varying farming activities in a "catchment context". This research has resulted in the development of a much-improved understanding of the likely impacts of changed management practices at the farm-scale as well as the development of a number of conceptual models which place farming within this broader catchment context. The project discussed in this paper transformed a conceptual model of dairy farm phosphorus (P) management and transport processes into a more temporally and spatially dynamic model. This was then loaded with catchment-specific data and used as a "policy support tool" to allow the Australian dairy industry to examine the potential farm and catchment-scale impacts of varying dairy farm management practices within some key dairy farming regions. Models were developed, validated and calibrated using "STELLA©" dynamic modelling software for three catchments in which dairy is perceived as a significant land use. The models describe P movement and cycling within and through dairy farms in great detail and also estimate P transport through major source, sink and flow sectors of the catchments. A series of scenarios were executed for all three catchments which examined three main "groups" of tests: changes to farm P input rates; implementation of perceived environmental "Best Management Practices" (BMPs), and; changes to land use mosaics. Modifications to actual P input rates into dairy farms (not surprisingly) had a major effect on nutrient transport within and from the farms with a significant rise in nutrient loss rates at all scales with increasing fertiliser use. More surprisingly, however, even extensive environmental BMP implementation did not have marked effects on off-farm nutrient loss rates. On and off-farm riparian management implemented

  4. Farm population of the United States: 1986.

    PubMed

    Deare, D; Kalbacher, J Z

    1987-11-01

    This report presents annual estimates of selected social and economic characteristics of the farm population in 1986. Also included are fertility characteristics from the June 1986 Current Population Survey (CPS) and data from the March 1986 CPS supplement. The Census Bureau and the Economic Research Service of the Department of Agriculture prepared the farm population estimates for 1986 from CPS data. Highlights of the data follow. 1) About 5,226,000 persons lived on farms in rural areas of the US in 1986. About 1 of 46 persons, or 2.2% of the nation's population, had a farm residence in 1986, compared to 30.2% in 1920. The farm population consists of persons living on farms in rural areas of the country; it does not include residents of the small number of farms in urban areas. 2) No statistically significant change in the number of farm residents occurred between 1985 and 1986. 3) Half of all farm residents now live in the Midwest. The Southern farm population has rapidly declined to just 29% of the national total; its 11% loss over the last year made it the only 1 of the 4 geographic regions to experience a significant change in number of farm residents. 4) About 1/4 (1.3 million) of the farm population live in metropolitan areas, while 3/4 live in non metropolitan areas. 5) In 1986, 97% of farm residents were white, 2% black, and 2% hispanic. 6) The median age of rural farm residents was 37 years in 1986, which is significantly higher than the median of 31.6 years for the non-farm production. There were 110 men/100 women living on farms in 1986, compared with just 93 men/100 women in the nonfarm population. 7) About 69% of farm residents 15+ were married and living with a spouse, compared with 56% of nonfarm residents. 8) About 87% of farm households were made up of families; the comparable proportion of nonfarm families was 72%. The average size of the farm family is 3.18 members compared to 3.21 members/nonfarm family. 9) The number of children born to ever

  5. Hard-Copy versus Computer Presentation of the SuperShrink Interview Simulation.

    ERIC Educational Resources Information Center

    Sussman, Daniel; Lowman, Joseph

    1989-01-01

    Investigates the effects of realism and perceived control on student satisfaction with the SuperShrink interview. Compares active/passive and computer/hardcopy conditions. Findings show students rate the computer versions as more satisfying. Suggests computers are superior to hardcopy simulations of human interactions. (Author/NL)

  6. Alcohol fuel from Ohio farms

    SciTech Connect

    Not Available

    1980-01-01

    Brief descriptions of on-farm ethanol production methods including feedstock preparation, cooking, fermentation, and distillation are presented. Safety conditions are described. Investment in on-farm ethanol production facilities and their potential returns are addressed. The market for ethanol and ethanol blends as well as for by-products is encouraging. Legal aspects for permitting and environmental regulations both for Ohio and federal agencies are discussed. (DMC)

  7. Simulating tissue oxygenation by encapsulating hemoglobin in polymer microcapsules (Conference Presentation)

    NASA Astrophysics Data System (ADS)

    Liu, Guangli; Wu, Qiang; Shen, Shuwei; Zhao, Gang; Dong, Erbao; Xu, Ronald X.

    2017-03-01

    We describe a combination of liquid-jet microencapsulation and molding techniques to fabricate tissue-simulating phantoms that mimick functional characteristics of tissue oxygen saturation (StO2). Chicken hemoglobin (Hb) was encapsulated inside a photocurable resin by a coaxial flow focusing process. The microdroplets were cured by ultraviolet (UV) illumination to form Hb loaded polymersome microdroplets. The microdroplets were further freeze-dried to form semipermeable solid microcapules with an outer transparent polymeric shell and an inner core of Hb. The diameter of the microcapsules ranged from 50 to100 μm. The absorption spectrum of the microcapsules was measured by a UV/VIS spectrophotometer over a wavelength range from 400 nm to 1100 nm. To fabricate the tissue-simulating phantom, the Hb loaded microcapsules were dispersed in transparent polydimethylsiloxane (PDMS). The optical properties of the phantom were determined by an vertical double integrating sphere with a reconstruction algorithm. The experimental results showed that the tissue-simulating phantom exhibited the spectral characteristics closely resembling that of oxy-hemoglobin. The phantom had a long-term optical stability when stored in 4 ℃, indicating that microencapsulation effectively protected Hb and improved its shelf time. With the Hb loaded microcapsules, we will produce skin-simulating phantoms for quantitative validation of multispectral imaging techniques. To the best of the authors' knowledge, no solid phantom is able to mimick living tissue oxygenation with good agreement. Therefore, our work provided an engineering platform for validating and calibrating spectral optical devices in biomedical applications.

  8. The Effect of Stereoscopic Presentation on a Simulated Air Traffic Control Task

    DTIC Science & Technology

    1989-12-01

    B87-17 No. in Program of Work : 731.3 SUMMARY Collision prediction in a simulated Air Traffic Control (ATC) task was compared for conditions in...increasing density and complexity of air traffic, the work load in Air Traffic Control (ATC) has become a matter of great concern. One of the factors that...three-dimensional space he is working in, should be welcome. One possibility would be colour coding, an application that has finally become well

  9. Reflectance confocal microscopy of red blood cells: simulation and experiment (Conference Presentation)

    NASA Astrophysics Data System (ADS)

    Zeidan, Adel; Yeheskely-Hayon, Daniella; Minai, Limor; Yelin, Dvir

    2016-03-01

    The properties of red blood cells are a remarkable indicator of the body's physiological condition; their density could indicate anemia or polycythemia, their absorption spectrum correlates with blood oxygenation, and their morphology is highly sensitive to various pathologic states including iron deficiency, ovalocytosis, and sickle cell disease. Therefore, measuring the morphology of red blood cells is important for clinical diagnosis, providing valuable indications on a patient's health. In this work, we simulated the appearance of normal red blood cells under a reflectance confocal microscope and discovered unique relations between the cells' morphological parameters and the resulting characteristic interference patterns. The simulation results showed good agreement with in vitro reflectance confocal images of red blood cells, acquired using spectrally encoded flow cytometry (SEFC) that imaged the cells during linear flow and without artificial staining. By matching the simulated patterns to the SEFC images of the cells, the cells' three-dimensional shapes were evaluated and their volumes were calculated. Potential applications include measurement of the mean corpuscular volume, cell morphological abnormalities, cell stiffness under mechanical stimuli, and the detection of various hematological diseases.

  10. LES of large wind farm during a diurnal cycle: Analysis of Energy and Scalar flux budgets

    NASA Astrophysics Data System (ADS)

    Sharma, V.; Calaf, M.; Parlange, M. B.

    2014-12-01

    With an expanding role of wind energy in satisfying energy demands around the world, wind farms are covering increasingly larger surfaces to the point where interaction between wind farms and the atmospheric boundary layer (ABL) might have significant implications. Furthermore, many wind farm sites lie over existing farmland for which water is a precious resource. In this context, a relevant question yet to be fully understood, is whether large wind farms alter near surface temperatures and evaporation rates and if so, by how much. In the present study, Large Eddy Simulation (LES) of a geostrophic wind driven ABL with two active scalars, temperature and specific humidity, in the presence of Coriolis forces with an embedded wind farm are performed. Multiple 'synthetic' diurnal cycles are simulated by imposing a time-varying surface temperature and specific humidity. Wind turbines are modeled using the "actuator disk" approach along with the flexibility to reorient according to varying flow directions. LES is performed using the "pseudo-spectral" approach implying that an infinitely large wind farm is simulated. Comparison of simulations with and without wind farms show clear differences in vertical profiles of horizontal velocity magnitude and direction, turbulent kinetic energy and scalar fluxes. To better understand these differences, a detailed analysis of the constituent terms of budget equations of mean and turbulent kinetic energy and sensible and latent heat fluxes has been performed for different stratification regimes as the ABL evolves during the diurnal cycle. The analyses help explain the effect of wind farms on the characteristics of the low-level jet, depth of the stable boundary layer, formation and growth of the convective boundary layer (CBL) and scalar fluxes at the surface.

  11. Review of numerical methods for simulation of the aortic root: Present and future directions

    NASA Astrophysics Data System (ADS)

    Mohammadi, Hossein; Cartier, Raymond; Mongrain, Rosaire

    2016-05-01

    Heart valvular disease is still one of the main causes of mortality and morbidity in develop countries. Numerical modeling has gained considerable attention in studying hemodynamic conditions associated with valve abnormalities. Simulating the large displacement of the valve in the course of the cardiac cycle needs a well-suited numerical method to capture the natural biomechanical phenomena which happens in the valve. The paper aims to review the principal progress of the numerical approaches for studying the hemodynamic of the aortic valve. In addition, the future directions of the current approaches as well as their potential clinical applications are discussed.

  12. Numerical Relativity and Black Hole Binaries: The historical path to present simulations

    NASA Astrophysics Data System (ADS)

    Laguna, Pablo

    2012-03-01

    The numerical relativity landscape at the turn of the century reached a unique transformative moment. A time with the ripe conditions to solve one of the grand challenges in computational physics: the two-body problem in general relativity. The computational modeling of two black holes as they coalesce is a formidable undertaking, requiring the most powerful hardware, innovative algorithms and creativity. This talk provides a historical perspective of the developments that led to the current success we enjoy of binary black hole simulations as genuine tools of discovery in the new astronomy of gravitational waves.

  13. Simulations of Decadal-scale Climate Change Impacts on Agriculture: Attributing Trends in Regional Corn Yields to Physiological Effects Versus Adjusted Farm Management

    NASA Astrophysics Data System (ADS)

    Kucharik, C.

    2003-12-01

    A recent study published in Science in early 2003 [by David Lobell and Gregory Asner, Dept. of Global Ecology, Carnegie Inst. of Washington] highlighted that little effort has been put forth to understand the impacts of previous decadal-scale climate changes on row-crop agriculture. The major obstacle to overcome in quantifying crop response to climate changes over large regions is deciphering between changes attributed to climate change versus technology, land-management and other factors. While the Lobell and Asner study concluded that regional temperature trends potentially contributed to corn and soybean yield trends from 1982-1998, a partitioning of the observed increases between direct physiological effects versus farmer management adjustment to climate was not a goal of their study. As part of this study, an agricultural version of the Integrated BIosphere Simulator (Agro-IBIS), was used to investigate how decadal-scale climate changes may have contributed to corn yield trends across the Mississippi Basin from 1948-2001. The primary objective was to investigate the relative contributions of physiological effects and farmer adjustments in planting date and hybrid choice to long-term corn yield trends. The impacts of advancing technology on agriculture were removed from model simulations so that the impact of weather and farm management decisions (e.g., planting date and hybrid choice) could be separated from observed long-term trends in the USDA crop yield record. Scenarios were used that accounted for smart-farmers, where management adjustments (planting date and/or hybrid) were made in response to climate changes, and for business-as-usual-farmers who continued to plant the same hybrids on the same date during the study period. When average, optimum corn planting dates from the 1950s were compared with the 1990s, significant springtime warming in regions of the northern fringes of the cornbelt (e.g., North Dakota, Minnesota) over the past 40 years have

  14. Simulation and analysis of light scattering by multilamellar bodies present in the human eye.

    PubMed

    Méndez-Aguilar, Emilia M; Kelly-Pérez, Ismael; Berriel-Valdos, L R; Delgado-Atencio, José A

    2017-06-01

    A modified computational model of the human eye was used to obtain and compare different probability density functions, radial profiles of light pattern distributions, and images of the point spread function formed in the human retina under the presence of different kinds of particles inside crystalline lenses suffering from cataracts. Specifically, this work uses simple particles without shells and multilamellar bodies (MLBs) with shells. The emergence of such particles alters the formation of images on the retina. Moreover, the MLBs change over time, which affects properties such as the refractive index of their shell. Hence, this work not only simulates the presence of such particles but also evaluates the incidence of particle parameters such as particle diameter, particle thickness, and shell refractive index, which are set based on reported experimental values. In addition, two wavelengths (400 nm and 700 nm) are used for light passing through the different layers of the computational model. The effects of these parameters on light scattering are analyzed using the simulation results. Further, in these results, the effects of light scattering on image formation can be seen when single particles, early-stage MLBs, or mature MLBs are incorporated in the model. Finally, it is found that particle diameter has the greatest impact on image formation.

  15. Simulation and analysis of light scattering by multilamellar bodies present in the human eye

    PubMed Central

    Méndez-Aguilar, Emilia M.; Kelly-Pérez, Ismael; Berriel-Valdos, L. R.; Delgado-Atencio, José A.

    2017-01-01

    A modified computational model of the human eye was used to obtain and compare different probability density functions, radial profiles of light pattern distributions, and images of the point spread function formed in the human retina under the presence of different kinds of particles inside crystalline lenses suffering from cataracts. Specifically, this work uses simple particles without shells and multilamellar bodies (MLBs) with shells. The emergence of such particles alters the formation of images on the retina. Moreover, the MLBs change over time, which affects properties such as the refractive index of their shell. Hence, this work not only simulates the presence of such particles but also evaluates the incidence of particle parameters such as particle diameter, particle thickness, and shell refractive index, which are set based on reported experimental values. In addition, two wavelengths (400 nm and 700 nm) are used for light passing through the different layers of the computational model. The effects of these parameters on light scattering are analyzed using the simulation results. Further, in these results, the effects of light scattering on image formation can be seen when single particles, early-stage MLBs, or mature MLBs are incorporated in the model. Finally, it is found that particle diameter has the greatest impact on image formation. PMID:28663924

  16. Plasma flow and fast particles in a hypervelocity accelerator - A color presentation. [micrometeoroid simulation

    NASA Technical Reports Server (NTRS)

    Igenbergs, E. B.; Cour-Palais, B.; Fisher, E.; Stehle, O.

    1975-01-01

    A new concept for particle acceleration for micrometeoroid simulation was developed at NASA Marshall Space Flight Center, using a high-density self-luminescent fast plasma flow to accelerate glass beads (with a diameter up to 1.0 mm) to velocities between 15-20 km/sec. After a short introduction to the operation of the hypervelocity range, the eight-converter-camera unit used for the photographs of the plasma flow and the accelerated particles is described. These photographs are obtained with an eight-segment reflecting pyramidal beam splitter. Wratten filters were mounted between the beam splitter and the converter tubes of the cameras. The photographs, which were recorded on black and white film, were used to make the matrices for the dye-color process, which produced the prints shown.

  17. Plasma flow and fast particles in a hypervelocity accelerator - A color presentation. [micrometeoroid simulation

    NASA Technical Reports Server (NTRS)

    Igenbergs, E. B.; Cour-Palais, B.; Fisher, E.; Stehle, O.

    1975-01-01

    A new concept for particle acceleration for micrometeoroid simulation was developed at NASA Marshall Space Flight Center, using a high-density self-luminescent fast plasma flow to accelerate glass beads (with a diameter up to 1.0 mm) to velocities between 15-20 km/sec. After a short introduction to the operation of the hypervelocity range, the eight-converter-camera unit used for the photographs of the plasma flow and the accelerated particles is described. These photographs are obtained with an eight-segment reflecting pyramidal beam splitter. Wratten filters were mounted between the beam splitter and the converter tubes of the cameras. The photographs, which were recorded on black and white film, were used to make the matrices for the dye-color process, which produced the prints shown.

  18. Photoelectron scattering and acid release in EUV lithography: a simulation study (Conference Presentation)

    NASA Astrophysics Data System (ADS)

    Biafore, John J.

    2017-03-01

    Abstract BACKGROUND: The ionizing wavelength in extreme ultraviolet (EUV) resist exposure leads to photoelectron scattering and uncertainty in the resulting acid image, producing line-edge roughness (LER) and poor CD uniformity of the printed features. GOALS: Try to determine how photoelectron and acid exposure blur effects affect EUV lithography and how they might be better controlled. Try to determine whether or not, and if so under what conditions, high resist quantum yields are beneficial to EUV lithography. METHODS: Using a stochastic resist simulator, we study the effects of resist properties upon photoelectric scattering, the uncertainty in the acid release and the properties of the after-development photoresist image in high NA EUV lithography. Uncertainty in the release of acids is the fundamental cause of LER and the ultimate limiter of optical lithography technology.

  19. Farm Safety

    PubMed Central

    Wilson, G. S.

    1966-01-01

    Accident and safety are related terms; the higher the accident rate in any industry, the greater is the need for safety measures designed to prevent accidents. This article discusses the accident and safety problems in agriculture, which includes horticulture and forestry. There is still a tendency among townspeople to think of the countryside as peaceful and tranquil, a place where nothing happens very quickly and far removed from violent death or crippling injury. This pleasant rustic picture has undergone a striking change in the last 30 years owing to considerable agricultural mechanization and the development of chemical pesticides, which have brought new dangers to those who live and work on the land. Although men have readily adapted themselves to new machines and methods, they have not proved as able to recognize new dangers and learn how to guard against them. In consequence, accidents have increased to such an extent that the whole industry has realized the need for positive preventive measures. In this country, it is generally accepted that an employer of labour has a responsibility to provide safe working conditions for those he employs. Farm safety legislation goes a little further and usually requires an employer to provide necessary safeguards, with the added requirement on a worker to make use of them. It is a feature of accident prevention work that it never reaches a stage when it can be regarded as complete. Even when a reduction in accidents has been achieved, the effort must be sustained or the trend will be quickly reversed. Images PMID:5904095

  20. Assessing Possible Climatic Impacts of Large Wind Farms Using Satellite Data

    NASA Astrophysics Data System (ADS)

    Zhou, Liming; Tian, Yuhong; Baidya Roy, Somnath

    2013-04-01

    This is an invited talk. A growing number of numerical simulations with hypothetical wind farms generally agree that large wind farms might affect local to regional weather and climate. Here we present observational evidence for such impacts based on analyses of satellite derived land surface temperature (LST) data at ~1.1 km for the period of 2003-2011 over a region in West-Central Texas, where four of the world's largest wind farms are located. A warming effect is observed at nighttime over wind farms relative to nearby non-wind-farm regions while the effect at daytime is small. Its spatial pattern couples very well with wind turbines geographically, particularly at nighttime in summer, and its magnitude exhibits a persistent upward trend, corresponding to the increase of operating wind turbines with time. There are no evident changes in land surface properties over the wind farm region. No warming effects are seen for a nearby non-wind-farm region with similar topography, particularly over high elevation ridges where the wind turbines are mostly built. Together, these results suggest that the warming effect observed in MODIS over wind farms are very likely attributable to the development of wind farms. This inference is also consistent with the diurnal and seasonal variations in the frequency of wind speed and direction distribution and the changes in near-surface atmospheric boundary layer (ABL) conditions due to wind farm operations. The nocturnal ABL is typically stable and much thinner than the daytime ABL and hence the turbine enhanced vertical mixing produces a stronger nighttime effect. The stronger wind speed and the higher frequency of the wind speed within the optimal power generation range in summer than winter and at nighttime than daytime likely drives wind turbines to generate more electricity and turbulence and consequently results in the strongest warming effect at nighttime in summer. Overall, the warming effect reported here is local and small

  1. Data Farming and Defense Applications

    NASA Technical Reports Server (NTRS)

    Horne, Gary; Meyer, Ted

    2011-01-01

    .Data farm,ing uses simulation modeling, high performance computing, experimental design and analysis to examine questions of interest with large possibility spaces. This methodology allows for the examination of whole landscapes of potential outcomes and provides the capability of executing enough experiments so that outliers might be captured and examined for insights. It can be used to conduct sensitivity studies, to support validation and verification of models, to iteratively optimize outputs using heuristic search and discovery, and as an aid to decision-makers in understanding complex relationships of factors. In this paper we describe efforts at the Naval Postgraduate School in developing these new and emerging tools. We also discuss data farming in the context of application to questions inherent in military decision-making. The particular application we illustrate here is social network modeling to support the countering of improvised explosive devices.

  2. Stochastic dynamic simulation modeling including multitrait genetics to estimate genetic, technical, and financial consequences of dairy farm reproduction and selection strategies.

    PubMed

    Kaniyamattam, K; Elzo, M A; Cole, J B; De Vries, A

    2016-10-01

    The objective of this study was to develop a daily stochastic dynamic dairy simulation model that included multitrait genetics and to evaluate the effects of reduced genetic models and various reproduction and selection strategies on the genetic, technical, and financial performance of a dairy herd. The 12 correlated genetic traits included in the 2014 lifetime net merit (NM$) index were modeled for each animal. For each animal, a true breeding value (TBV) for each trait was calculated as the average of the sire's and dam's TBV, plus a fraction of the inbreeding and Mendelian sampling variability. Similarly, an environmental component for each trait was calculated and was partitioned into a permanent and a daily (temporary) effect. The combined TBV and environmental effects were converted into the phenotypic performance of each animal. Hence, genetics and phenotypic performances were associated. Estimated breeding values (EBV) were also simulated. Genetic trends for each trait for the service sire were based on expected trends in US Holsteins. Surplus heifers were culled based on various ranking criteria to maintain a herd size of 1,000 milking cows. In the first 8 scenarios, culling of surplus heifers was either random or based on the EBV of NM$. Four different genetic models, depending on the presence or absence of genetic trends or genetic and environmental correlations, or both, were evaluated to measure the effect of excluding multitrait genetics on animal performance. In the last 5 scenarios, the full genetic model was used and culling of surplus heifers was either random or based on the EBV of NM$ or the EBV of milk. Sexed semen use and reliability of the EBV were also varied. Each scenario was simulated for 15yr into the future. Results showed that genetic models without all 12 genetic trends and genetic and environmental correlations provided biased estimates of the genetic, technical, and financial performance of the dairy herd. Average TBV of NM$ of all

  3. How to reduce long-term drift in present-day and deep-time simulations?

    NASA Astrophysics Data System (ADS)

    Brunetti, Maura; Vérard, Christian

    2017-09-01

    Climate models are often affected by long-term drift that is revealed by the evolution of global variables such as the ocean temperature or the surface air temperature. This spurious trend reduces the fidelity to initial conditions and has a great influence on the equilibrium climate after long simulation times. Useful insight on the nature of the climate drift can be obtained using two global metrics, i.e. the energy imbalance at the top of the atmosphere and at the ocean surface. The former is an indicator of the limitations within a given climate model, at the level of both numerical implementation and physical parameterisations, while the latter is an indicator of the goodness of the tuning procedure. Using the MIT general circulation model, we construct different configurations with various degree of complexity (i.e. different parameterisations for the bulk cloud albedo, inclusion or not of friction heating, different bathymetry configurations) to which we apply the same tuning procedure in order to obtain control runs for fixed external forcing where the climate drift is minimised. We find that the interplay between tuning procedure and different configurations of the same climate model provides crucial information on the stability of the control runs and on the goodness of a given parameterisation. This approach is particularly relevant for constructing good-quality control runs of the geological past where huge uncertainties are found in both initial and boundary conditions. We will focus on robust results that can be generally applied to other climate models.

  4. Farm-level economic impact of no-till farming in the Fort Cobb reservoir watershed

    USDA-ARS?s Scientific Manuscript database

    Survey data from the Fort Cobb Reservoir watershed (FCRW) in southwestern Oklahoma were used to evaluate farm-level management practices for no-till and conventional tillage. The Farm-level Economic Model (FEM), an annual economic simulation model, was used to determine impacts of alternative tilla...

  5. Multimodel ensemble simulations of present-day and near-future tropospheric ozone

    NASA Astrophysics Data System (ADS)

    Stevenson, D. S.; Dentener, F. J.; Schultz, M. G.; Ellingsen, K.; van Noije, T. P. C.; Wild, O.; Zeng, G.; Amann, M.; Atherton, C. S.; Bell, N.; Bergmann, D. J.; Bey, I.; Butler, T.; Cofala, J.; Collins, W. J.; Derwent, R. G.; Doherty, R. M.; Drevet, J.; Eskes, H. J.; Fiore, A. M.; Gauss, M.; Hauglustaine, D. A.; Horowitz, L. W.; Isaksen, I. S. A.; Krol, M. C.; Lamarque, J.-F.; Lawrence, M. G.; Montanaro, V.; Müller, J.-F.; Pitari, G.; Prather, M. J.; Pyle, J. A.; Rast, S.; Rodriguez, J. M.; Sanderson, M. G.; Savage, N. H.; Shindell, D. T.; Strahan, S. E.; Sudo, K.; Szopa, S.

    2006-04-01

    Global tropospheric ozone distributions, budgets, and radiative forcings from an ensemble of 26 state-of-the-art atmospheric chemistry models have been intercompared and synthesized as part of a wider study into both the air quality and climate roles of ozone. Results from three 2030 emissions scenarios, broadly representing "optimistic," "likely," and "pessimistic" options, are compared to a base year 2000 simulation. This base case realistically represents the current global distribution of tropospheric ozone. A further set of simulations considers the influence of climate change over the same time period by forcing the central emissions scenario with a surface warming of around 0.7K. The use of a large multimodel ensemble allows us to identify key areas of uncertainty and improves the robustness of the results. Ensemble mean changes in tropospheric ozone burden between 2000 and 2030 for the 3 scenarios range from a 5% decrease, through a 6% increase, to a 15% increase. The intermodel uncertainty (±1 standard deviation) associated with these values is about ±25%. Model outliers have no significant influence on the ensemble mean results. Combining ozone and methane changes, the three scenarios produce radiative forcings of -50, 180, and 300 mW m-2, compared to a CO2 forcing over the same time period of 800-1100 mW m-2. These values indicate the importance of air pollution emissions in short- to medium-term climate forcing and the potential for stringent/lax control measures to improve/worsen future climate forcing. The model sensitivity of ozone to imposed climate change varies between models but modulates zonal mean mixing ratios by ±5 ppbv via a variety of feedback mechanisms, in particular those involving water vapor and stratosphere-troposphere exchange. This level of climate change also reduces the methane lifetime by around 4%. The ensemble mean year 2000 tropospheric ozone budget indicates chemical production, chemical destruction, dry deposition and

  6. Independent Review of Simulation of Net Infiltration for Present-Day and Potential Future Climates

    SciTech Connect

    Review Panel: Soroosh Sorooshian, Ph.D., Panel Chairperson, University of California, Irvine; Jan M. H. Hendrickx, Ph.D., New Mexico Institute of Mining and Technology; Binayak P. Mohanty, Ph.D., Texas A&M University; Scott W. Tyler, Ph.D., University of Nevada, Reno; Tian-Chyi Jim Yeh, Ph.D., University of Arizona -- ORISE Review Facilitators: Robert S. Turner, Ph.D., Technical Review Group Manager, Oak Ridge Institute for Science and Education; Brian R. Herndon, Project Manager, Oak Ridge Institute for Science and Education; Russ Manning, Technical Writer /Editor, Haselwood Enterprises, Inc.

    2008-08-30

    The DOE Office of Civilian Radioactive Waste Management (OCRWM) tasked Oak Ridge Institute for Science and Education (ORISE) with providing an independent expert review of the documented model and prediction results for net infiltration of water into the unsaturated zone at Yucca Mountain. The specific purpose of the model, as documented in the report MDL-NBS-HS-000023, Rev. 01, is “to provide a spatial representation, including epistemic and aleatory uncertainty, of the predicted mean annual net infiltration at the Yucca Mountain site ...” (p. 1-1) The expert review panel assembled by ORISE concluded that the model report does not provide a technically credible spatial representation of net infiltration at Yucca Mountain. Specifically, the ORISE Review Panel found that: • A critical lack of site-specific meteorological, surface, and subsurface information prevents verification of (i) the net infiltration estimates, (ii) the uncertainty estimates of parameters caused by their spatial variability, and (iii) the assumptions used by the modelers (ranges and distributions) for the characterization of parameters. The paucity of site-specific data used by the modeling team for model implementation and validation is a major deficiency in this effort. • The model does not incorporate at least one potentially important hydrologic process. Subsurface lateral flow is not accounted for by the model, and the assumption that the effect of subsurface lateral flow is negligible is not adequately justified. This issue is especially critical for the wetter climate periods. This omission may be one reason the model results appear to underestimate net infiltration beneath wash environments and therefore imprecisely represent the spatial variability of net infiltration. • While the model uses assumptions consistently, such as uniform soil depths and a constant vegetation rooting depth, such assumptions may not be appropriate for this net infiltration simulation because they

  7. A simple approach for electron-electron scattering in nonequilibrium Green's function simulations (Conference Presentation)

    NASA Astrophysics Data System (ADS)

    Winge, David O.; Franckie, Martin; Verozzi, Claudio; Wacker, Andreas; Pereira, Mauro F.

    2016-10-01

    Regardless of all the success of Mid Infrared Quantum Cascade Lasers (QCLs), they still do not operate at room temperature in the THz range. The main temperature degrading mechanism for THz QCLs is not known in time of writing this abstract and it is still a topic of debate by the community [S. Khanal et al, J. Opt. 16 094001, 2014]. This is a challenge to theory and it is crucial to treat all possible scattering channels with the same mathematical footing. A summary of different methods for simulating these structures is found in [C. Jirauschek et al, Appl. Phys. Rev. 1 011307, 2014]. In this work we include and study the effects of electron-electron scattering via the Single Plasmon Pole Approximation (SPPA). In this approximation we capture both the static limit as well as dynamic effects. This gives an energy dependent (non-local in time) interaction beyond the Hartree-Fock approximation. This has been studied in a similar model with promising results [T. Schmielau and M.F. Pereira, Appl. Phys. Lett. 95 231111, 2009], and with this work we want to adapt the idea into the model described in Ref. [A. Wacker et a, IEEE Journal of Sel. Top. in Quantum Electron.,19 1200611, 2013]. We start by summarizing the theory underlying the SPPA and we show how it is implemented in the context of our formalism, by showing good agreement with the results for a four well quantum cascade laser [M. Amanti et al, New J. Phys. 11 125022, 2009].

  8. Simulating the Greenland ice sheet under present-day and palaeo constraints including a new discharge parameterization

    NASA Astrophysics Data System (ADS)

    Calov, R.; Robinson, A.; Perrette, M.; Ganopolski, A.

    2015-02-01

    In this paper, we propose a new sub-grid scale parameterization for the ice discharge into the ocean through outlet glaciers and inspect the role of different observational and palaeo constraints for the choice of an optimal set of model parameters. This parameterization was introduced into the polythermal ice-sheet model SICOPOLIS, which is coupled to the regional climate model of intermediate complexity REMBO. Using the coupled model, we performed large ensemble simulations over the last two glacial cycles by varying two major parameters: a melt parameter in the surface melt scheme of REMBO and a discharge scaling parameter in our parameterization of ice discharge. Our empirical constraints are the present-day Greenland ice sheet surface elevation, the surface mass balance partition (ratio between total ice discharge and total precipitation) and the Eemian interglacial elevation drop relative to present day in the vicinity of the NEEM ice core. We show that the ice discharge parameterization enables us to simulate both the correct ice-sheet shape and mass balance partition at the same time without explicitly resolving the Greenland outlet glaciers. For model verification, we compare the simulated total and sectoral ice discharge with other estimates. For the model versions that are consistent with the range of observational and palaeo constraints, our simulated Greenland ice sheet contribution to Eemian sea-level rise relative to present-day amounts to 1.4 m on average (in the range of 0.6 and 2.5 m).

  9. Visual Suppression of Monocularly Presented Symbology Against a Fused Background in a Simulation and Training Environment

    DTIC Science & Technology

    2006-05-01

    rivalry. Liu et al40 also found that the presence of a fused aperture surrounding a set of test stimuli minimized the occurrence of rivalry. Thus, it...Procedure Observers were first tested for acuity, phoria, depth perception, sighting dominance, and rivalry dominance. An Optec vision tester was used...observers are needed to test this hypothesis. Taken together, the results of the two experiments presented here indicate that observers may take a

  10. Mineralization of reactive azo dyes present in simulated textile waste water using down flow microaerophilic fixed film bioreactor.

    PubMed

    Balapure, Kshama; Bhatt, Nikhil; Madamwar, Datta

    2015-01-01

    The present research emphasizes on degradation of azo dyes from simulated textile wastewater using down flow microaerophilic fixed film reactor. Degradation of simulated textile wastewater (COD 7200mg/L and dye concentration 300mg/L) was studied in a microaerophilic fixed film reactor using pumice stone as a support material under varying hydraulic retention time (HRT) and organic loading rate (OLR). The intense metabolic activity of the inoculated bacterial consortium in the reactor led to 97.5% COD reduction and 99.5% decolorization of simulated wastewater operated under OLR of 7.2kgCODm(3)/d and 24h of HRT. FTIR, (1)H NMR and GC-MS studies revealed the formation of lower molecular weight aliphatic compounds under 24h of HRT, leading to complete mineralization of simulated wastewater. The detection of oxido-reductive enzyme activities suggested the enzymatic reduction of azo bonds prior to mineralization. Toxicity studies indicated that microbial treatment favors detoxification of simulated wastewater. Copyright © 2014 Elsevier Ltd. All rights reserved.

  11. Simulation of the present-day climate with the climate model INMCM5

    NASA Astrophysics Data System (ADS)

    Volodin, E. M.; Mortikov, E. V.; Kostrykin, S. V.; Galin, V. Ya.; Lykossov, V. N.; Gritsun, A. S.; Diansky, N. A.; Gusev, A. V.; Iakovlev, N. G.

    2017-02-01

    In this paper we present the fifth generation of the INMCM climate model that is being developed at the Institute of Numerical Mathematics of the Russian Academy of Sciences (INMCM5). The most important changes with respect to the previous version (INMCM4) were made in the atmospheric component of the model. Its vertical resolution was increased to resolve the upper stratosphere and the lower mesosphere. A more sophisticated parameterization of condensation and cloudiness formation was introduced as well. An aerosol module was incorporated into the model. The upgraded oceanic component has a modified dynamical core optimized for better implementation on parallel computers and has two times higher resolution in both horizontal directions. Analysis of the present-day climatology of the INMCM5 (based on the data of historical run for 1979-2005) shows moderate improvements in reproduction of basic circulation characteristics with respect to the previous version. Biases in the near-surface temperature and precipitation are slightly reduced compared with INMCM4 as well as biases in oceanic temperature, salinity and sea surface height. The most notable improvement over INMCM4 is the capability of the new model to reproduce the equatorial stratospheric quasi-biannual oscillation and statistics of sudden stratospheric warmings.

  12. A brief overview of transgenic farm animals.

    PubMed

    Bacci, M L

    2007-08-01

    Transgenesis offers new possibilities to rapidly modify the genome of living organisms. The application of transgenesis to farm animals faces many problems, more than those observed in the transgenesis of laboratory animals, as there are currently many different techniques available to obtain transgenic animals, which all have problems regarding low efficiency and high costs. When these techniques are applied to farm animals the problems concerning transgenesis are multiplied. Two main techniques, male pronuclear microinjection and sperm mediated gene transfer, utilised in farm animal transgenesis, are briefly presented. The improvement of these techniques and the employment of other biotechnologies such as cloning, could expand the uses of transgenic farm animals for human health.

  13. Accounting for the Variation of Driver Aggression in the Simulation of Conventional and Advanced Vehicles (Presentation)

    SciTech Connect

    Neubauer, J.; Wood, E.

    2013-05-01

    This presentation discusses a method of accounting for realistic levels of driver aggression to higher-level vehicle studies, including the impact of variation in real-world driving characteristics (acceleration and speed) on vehicle energy consumption and different powertrains (e.g., conventionally powered vehicles versus electrified drive vehicles [xEVs]). Aggression variation between drivers can increase fuel consumption by more than 50% or decrease it by more than 20% from average. The normalized fuel consumption deviation from average as a function of population percentile was found to be largely insensitive to powertrain. However, the traits of ideal driving behavior are a function of powertrain. In conventional vehicles, kinetic losses dominate rolling resistance and aerodynamic losses. In xEVs with regenerative braking, rolling resistance and aerodynamic losses dominate. The relation of fuel consumption predicted from real-world drive data to that predicted by the industry-standard HWFET, UDDS, LA92, and US06 drive cycles was not consistent across powertrains, and varied broadly from the mean, median, and mode of real-world driving. A drive cycle synthesized by NREL's DRIVE tool accurately and consistently reproduces average real-world for multiple powertrains within 1%, and can be used to calculate the fuel consumption effects of varying levels of driver aggression.

  14. Simulation of Net Infiltration for Present-Day and Potential Future Climates

    SciTech Connect

    D. Levitt

    2004-11-09

    The purpose of this model report is to document the infiltration model used to estimate upper-bound, mean, and lower-bound spatially-distributed average annual net infiltration rates for present-day and potential future climates at Yucca Mountain, Nevada. Net infiltration is the component of infiltrated precipitation, snowmelt, or surface water run-on that has percolated below the zone of evapotranspiration as defined by the depth of the effective root zone. The estimates of net infiltration are primarily used for defining the upper boundary condition for the site-scale three-dimensional unsaturated zone (UZ) model. The UZ flow model is one of several process models abstracted by the total system performance assessment (TSPA) model used to evaluate performance of the repository at Yucca Mountain, Nevada. The net-infiltration model is important for assessing repository-system performance because output from this model provides the upper boundary condition for the UZ flow model used to generate flow fields; water percolating downward from the UZ will be the principal means by which radionuclides are potentially released to the saturated zone (SZ). The SZ is the principal pathway to the biosphere where the reasonably maximally exposed individual (RMEI) is exposed to radionuclides.

  15. Farm Parents' Attitudes Towards Farm Safety Experts

    ERIC Educational Resources Information Center

    Neufeld, Steven J.; Cinnamon, Jennifer L.

    2004-01-01

    Using both qualitative and quantitative data, this article analyzes farm parent's attitudes towards the trustworthiness, usefulness, and use of advice from farm safety experts. The article evaluates four different perspectives on trust in expert: the Validity of Knowledge perspective, the Salient Values Similarity perspective, the Diffusion of…

  16. Farm Parents' Attitudes Towards Farm Safety Experts

    ERIC Educational Resources Information Center

    Neufeld, Steven J.; Cinnamon, Jennifer L.

    2004-01-01

    Using both qualitative and quantitative data, this article analyzes farm parent's attitudes towards the trustworthiness, usefulness, and use of advice from farm safety experts. The article evaluates four different perspectives on trust in expert: the Validity of Knowledge perspective, the Salient Values Similarity perspective, the Diffusion of…

  17. Present and LGM permafrost from climate simulations: contribution of statistical downscaling

    NASA Astrophysics Data System (ADS)

    Levavasseur, G.; Vrac, M.; Roche, D. M.; Paillard, D.; Martin, A.; Vandenberghe, J.

    2010-10-01

    We quantify the agreement between permafrost distributions from PMIP2 (Paleoclimate Modeling Intercomparison Project) climate models and permafrost data. We evaluate the ability of several climate models to represent permafrost and assess the inter-variability between them. Studying an heterogeneous variable such as permafrost implies to conduct analysis at a smaller spatial scale compared with climate models resolution. Our approach consists in applying statistical downscaling methods (SDMs) on large- or regional-scale atmospheric variables provided by climate models, leading to local permafrost modelling. Among the SDMs, we first choose a transfer function approach based on Generalized Additive Models (GAMs) to produce high-resolution climatology of surface air temperature (SAT). Then, we define permafrost distribution over Eurasia by SAT conditions. In a first validation step on present climate (CTRL period), GAM shows some limitations with non-systemic improvements in comparison with the large-scale fields. So, we develop an alternative method of statistical downscaling based on a stochastic generator approach through a Multinomial Logistic Regression (MLR), which directly models the probabilities of local permafrost indices. The obtained permafrost distributions appear in a better agreement with data. In both cases, the provided local information reduces the inter-variability between climate models. Nevertheless, this also proves that a simple relationship between permafrost and the SAT only is not always sufficient to represent local permafrost. Finally, we apply each method on a very different climate, the Last Glacial Maximum (LGM) time period, in order to quantify the ability of climate models to represent LGM permafrost. Our SDMs do not significantly improve permafrost distribution and do not reduce the inter-variability between climate models, at this period. We show that LGM permafrost distribution from climate models strongly depends on large-scale SAT

  18. General view looking toward the roulette farm cluster from south ...

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

    General view looking toward the roulette farm cluster from south to north; note the present-day field was an orchard at the time of the battle - Roulette Farm, House, Sharpsburg, Washington County, MD

  19. Using Mesoscale Weather Model Output as Boundary Conditions for Atmospheric Large-Eddy Simulations and Wind-Plant Aerodynamic Simulations (Presentation)

    SciTech Connect

    Churchfield, M. J.; Michalakes, J.; Vanderwende, B.; Lee, S.; Sprague, M. A.; Lundquist, J. K.; Moriarty, P. J.

    2013-10-01

    Wind plant aerodynamics are directly affected by the microscale weather, which is directly influenced by the mesoscale weather. Microscale weather refers to processes that occur within the atmospheric boundary layer with the largest scales being a few hundred meters to a few kilometers depending on the atmospheric stability of the boundary layer. Mesoscale weather refers to large weather patterns, such as weather fronts, with the largest scales being hundreds of kilometers wide. Sometimes microscale simulations that capture mesoscale-driven variations (changes in wind speed and direction over time or across the spatial extent of a wind plant) are important in wind plant analysis. In this paper, we present our preliminary work in coupling a mesoscale weather model with a microscale atmospheric large-eddy simulation model. The coupling is one-way beginning with the weather model and ending with a computational fluid dynamics solver using the weather model in coarse large-eddy simulation mode as an intermediary. We simulate one hour of daytime moderately convective microscale development driven by the mesoscale data, which are applied as initial and boundary conditions to the microscale domain, at a site in Iowa. We analyze the time and distance necessary for the smallest resolvable microscales to develop.

  20. The Distinguished American Farm.

    ERIC Educational Resources Information Center

    Surdovel, Catherine; Gruber, Marcella

    1994-01-01

    Describes the development of an elementary school curriculum on farms to give students a knowledge and appreciation of the farm as a food source and of the steps involved moving food from the farm to the table. Specific activities are suggested, and appropriate book titles are recommended. (Contains 10 references.) (LRW)

  1. North Carolina Farm Survey.

    ERIC Educational Resources Information Center

    Lilley, Stephen; And Others

    Interviews with 725 North Carolina farm operators revealed: the extent of economic, social, and emotional stresses on farm families; perceptions of the future of agriculture; the degree of reliance on off-farm income; financial management practices; and programs needed from the Agricultural Extension Service. Almost 66% viewed their future in…

  2. Forest farming practices

    Treesearch

    J.L. Chamberlain; D. Mitchell; T. Brigham; T. Hobby; L. Zabek; J. Davis

    2009-01-01

    Forest farming in North America is becoming popular as a way for landowners to diversify income opportunities, improve management of forest resources, and increase biological diversity. People have been informally "farming the forests" for generations. However, in recent years, attention has been directed at formalizing forest farming and improving it...

  3. A Farm Management Problem. Teacher Guide. AGDEX 810.

    ERIC Educational Resources Information Center

    Cackler, William

    This guide is intended to assist teachers in conducting a farm management simulation that has been designed to help vocational agriculture students acquire competency in both crop and livestock farming. The introductory section includes an overview of the simulation, planning considerations and suggested grading criteria, and a suggested sequence…

  4. Bringing the Classroom to the Farm.

    ERIC Educational Resources Information Center

    Peters, Robert R.; And Others

    1986-01-01

    Describes a study conducted to determine if extension agents could expand their audience through a series of statewide on-farm meetings. The study also sought to determine if the on-farm approach would result in adoption of recommended mastitis control practices. Results are presented and discussed. (CT)

  5. Bringing the Classroom to the Farm.

    ERIC Educational Resources Information Center

    Peters, Robert R.; And Others

    1986-01-01

    Describes a study conducted to determine if extension agents could expand their audience through a series of statewide on-farm meetings. The study also sought to determine if the on-farm approach would result in adoption of recommended mastitis control practices. Results are presented and discussed. (CT)

  6. Wind Farm Power System Model Development: Preprint

    SciTech Connect

    Muljadi, E.; Butterfield, C. P.

    2004-07-01

    In some areas, wind power has reached a level where it begins to impact grid operation and the stability of local utilities. In this paper, the model development for a large wind farm will be presented. Wind farm dynamic behavior and contribution to stability during transmission system faults will be examined.

  7. Influence of farm resource endowment on possibilities for sustainable development: a case study for vegetable farms in South Uruguay.

    PubMed

    Dogliotti, S; van Ittersum, M K; Rossing, W A H

    2006-02-01

    In different parts of the world, there is an urgent need for redesigning and innovating farming systems. Such a process may be supported by model-based explorations that enable ex-ante evaluation of a broad range of alternatives. Since a variety of viable patterns of farm development exists related to farm resource endowment and farmer's strategy, model-based explorations should be able to capture the existing variation in resource endowment and strategies in order to have impact on strategic farm management. In this paper, we present an overview of the model-based explorative method based on the MILP model Farm Images, applied to explore options for sustainable development of vegetable farms in Canelón Grande, Uruguay. The method is used to gain insight into the impact of current farm resource endowment on the possibilities for sustainable development and on the resource use efficiency at farm scale. We maximized farm income for 128 different farm types in an environment-oriented scenario and in an income-oriented scenario. Farm types were defined by combining 4 farm sizes, 2 labor endowments, 4 irrigation endowments, 2 soil quality combinations and 2 mechanization levels. The results demonstrate a strong impact of farm resource endowment on possibilities for sustainable development, as well as synergy between labor, land and irrigated area on resource-use efficiency at farm scale. Farms with 10ha of land or less, representing 47% of the farms in the Canelón Grande region, could only achieve a family income higher than the average income of Uruguayan families when the irrigated area was ca. 40% of the farm area. The achievement of environmental targets was less costly in terms of income on farms with a low rather than high labor availability per unit area and on farms with irrigation facilities.

  8. Presentation of the first PLM integrated optical simulation software for the design and engineering of optical systems

    NASA Astrophysics Data System (ADS)

    Delacour, Jacques F.; Cuinier, Jean-Luc

    2004-02-01

    The Computer Aided Design, Manufacturing and Engineering world has gradually welcomed simulation tools enabling the modeling of machining, thermal effects, mechanical, dynamic-motion, vibration and acoustic phenomena... but not optical simulation which has evolved independently from the CAD environment. The innovation presented here with SPEOS CAA V5 Based software integrated in CATIA and ENOVIA DMU V5 software from Dassault Systèmes, the premier global PLM solutions provider, is the first optical simulation solution connecting optics to the CAD/CAM/CAE world, and directly impacts and improve the optical design analysis and process. The optical properties are added directly within the software, sharing the same data for mechanical and optical analysis and thus avoiding all the transfer errors. This new approach improves the quality process and allows unlimited detailed mechanical parts used to be used for the simulation. All the geometric transformations and optical properties modifications are done interactively, helping the user to understand the way the photons are propagated in the whole system. New functions available in CATIA/ENOVIA V5 are light emission simulation, light/surface interaction and scattering, light/matter propagation producing optical performance, photometric measurements and stray light analysis. The early integration of optical performances means that a solution can be found faster that will globally fit to all the specifications. This new technology is opening new links with stress effects, thermal effects, mobile and motorized systems, ... during the design of an optical system, giving the ability to evaluate optical performance of any adaptive, opto-mechanical system, projection and display system under virtual environmental conditions (heat, stress,...) that will affect the optical performance.

  9. Monitoring, modeling and mitigating impacts of wind farms on local meteorology

    NASA Astrophysics Data System (ADS)

    Baidya Roy, Somnath; Traiteur, Justin; Kelley, Neil

    2010-05-01

    Wind power is one of the fastest growing sources of energy. Most of the growth is in the industrial sector comprising of large utility-scale wind farms. Recent modeling studies have suggested that such wind farms can significantly affect local and regional weather and climate. In this work, we present observational evidence of the impact of wind farms on near-surface air temperatures. Data from perhaps the only meteorological field campaign in an operational wind farm shows that downwind temperatures are lower during the daytime and higher at night compared to the upwind environment. Corresponding radiosonde profiles at the nearby Edwards Air Force Base WMO meteorological station show that the diurnal environment is unstable while the nocturnal environment is stable during the field campaign. This behavior is consistent with the hypothesis proposed by Baidya Roy et al. (JGR 2004) that states that turbulence generated in the wake of rotors enhance vertical mixing leading to a warming/cooling under positive/negative potential temperature lapse rates. We conducted a set of 306 simulations with the Regional Atmospheric Modeling System (RAMS) to test if regional climate models can capture the thermal effects of wind farms. We represented wind turbines with a subgrid parameterization that assumes rotors to be sinks of momentum and sources of turbulence. The simulated wind farms consistently generated a localized warming/cooling under positive/negative lapse rates as hypothesized. We found that these impacts are inversely correlated with background atmospheric boundary layer turbulence. Thus, if the background turbulence is high due to natural processes, the effects of additional turbulence generated by wind turbine rotors are likely to be small. We propose the following strategies to minimize impacts of wind farms: • Engineering solution: design rotors that generate less turbulence in their wakes. Sensitivity simulations show that these turbines also increase the

  10. The impact on the present and future East Asia climate of the land cover changes simulated by dynamic vegetation model

    NASA Astrophysics Data System (ADS)

    Boo, Kyung-On; Cho, Mee-Hyun; Martin, Gill; Lee, Johan

    2014-05-01

    Land surface properties are important because of their known impact on the East Asian monsoon circulation. Historical and future changes in land cover changes give influences on the monsoon rainfall and circulation over the Asian summer monsoon region. The dynamic vegetation model, as one of the key process of the Earth System model, simulates the terrestrial biosphere where the fraction of tree and grass species is a function of the local climate state. The potential effect of the simulated land cover distribution needs to be individually evaluated in present and future climate simulations. Since it is reported that the simulated land surface properties could give influence on the systematic biases in monsoon rainfall and add an impact in the future projection via feedback with the dust loading of the atmosphere [Martin and Levine, 2012]. Motivated by the previous study, we investigate the impact of land cover change generated by the interactive terrestrial carbon cycle in the HadGEM2 Earth System configuration over East Asia under present-day and possible future climate condition. Data in this study is HadGEM2-A runs using HadGEM2-ES land cover distribution in Martin and Levine [2012]. In present-day run, over the northern China region to the west of Korea, bare soil increase distinctly in HadGEM2-ES rather than HadGEM2-AO. ES land cover by interactive vegetation model gives influences on JJA rainfall and temperature. There is interaction with model systematic biases in the present-day climate. JJA dry bias is larger when HadGEM2-ES land cover distribution was used for Korea. Dust aerosol effect contributes to the dry bias. As bare soil fraction increases, more emitted dust aerosol has direct effect of negative net downward SW, cooling the land surface, weakening monsoon inflow, inducing dry bias over Korea. In the other hand, over bare soil expanded area, changes in roughness length and soil evaporation, the subsequent latent heat flux changes contribute to

  11. The Influence of Between-Farm Distance and Farm Size on the Spread of Classical Swine Fever during the 1997–1998 Epidemic in The Netherlands

    PubMed Central

    Roermund, Herman J. W. van.; Hagenaars, Thomas J.

    2014-01-01

    As the size of livestock farms in The Netherlands is on the increase for economic reasons, an important question is how disease introduction risks and risks of onward transmission scale with farm size (i.e. with the number of animals on the farm). Here we use the epidemic data of the 1997–1998 epidemic of Classical Swine Fever (CSF) Virus in The Netherlands to address this question for CSF risks. This dataset is one of the most powerful ones statistically as in this epidemic a total of 428 pig farms where infected, with the majority of farm sizes ranging between 27 and 1750 pigs, including piglets. We have extended the earlier models for the transmission risk as a function of between-farm distance, by adding two factors. These factors describe the effect of farm size on the susceptibility of a ‘receiving’ farm and on the infectivity of a ‘sending’ farm (or ‘source’ farm), respectively. Using the best-fitting model, we show that the size of a farm has a significant influence on both farm-level susceptibility and infectivity for CSF. Although larger farms are both more susceptible to CSF and, when infected, more infectious to other farms than smaller farms, the increase is less than linear. The higher the farm size, the smaller the effect of increments of farm size on the susceptibility and infectivity of a farm. Because of changes in the Dutch pig farming characteristics, a straightforward extrapolation of the observed farm size dependencies from 1997/1998 to present times would not be justified. However, based on our results one may expect that also for the current pig farming characteristics in The Netherlands, farm susceptibility and infectivity depend non-linearly on farm size, with some saturation effect for relatively large farm sizes. PMID:24748233

  12. The Roots of "Animal Farm".

    ERIC Educational Resources Information Center

    Schaefer, Barbara E.

    The presentation of the book "Animal Farm" by George Orwell to sophomores at East Orange Catholic High School, New Jersey, as a "political document" is discussed. Through research, panel discussions and voluntary comments, the students studied the book in depth comparing it to the power struggle between Stalin and Trotsky in…

  13. ANNUAL FARM LABOR REPORT - 1962.

    ERIC Educational Resources Information Center

    LENHART, MARGOT WAKEMAN

    THE ADMINISTRATION OF THE FARM PLACEMENT SERVICE WHICH INCLUDED ORGANIZATION, STAFF, OFFICES, ASSOCIATES AND ADVISORS, AND MEETINGS WAS PRESENTED. AT THE STATE LEVEL, THERE WAS A RISE IN OVERALL CROP PRODUCTION AND A DECREASE IN TOTAL CROPLAND HARVEST. AT THE LOCAL LEVEL, URBAN ENCROACHMENT CHANGED THE NATURE OF PRODUCTION IN SOME AREAS AND…

  14. ANNUAL FARM LABOR REPORT - 1962.

    ERIC Educational Resources Information Center

    LENHART, MARGOT WAKEMAN

    THE ADMINISTRATION OF THE FARM PLACEMENT SERVICE WHICH INCLUDED ORGANIZATION, STAFF, OFFICES, ASSOCIATES AND ADVISORS, AND MEETINGS WAS PRESENTED. AT THE STATE LEVEL, THERE WAS A RISE IN OVERALL CROP PRODUCTION AND A DECREASE IN TOTAL CROPLAND HARVEST. AT THE LOCAL LEVEL, URBAN ENCROACHMENT CHANGED THE NATURE OF PRODUCTION IN SOME AREAS AND…

  15. A Framework for the Comparative Analysis of Farm Organizations.

    ERIC Educational Resources Information Center

    Molnar, Joseph J.

    Presenting a model for the comparative analysis of farm organizations, this paper analyzes the farm firm as a complex organization; identifies key structural dimensions of an agricultural production unit; and reviews various organizational perspectives for their utility in understanding and explaining the behavior of farm operations and farm…

  16. A Framework for the Comparative Analysis of Farm Organizations.

    ERIC Educational Resources Information Center

    Molnar, Joseph J.

    Presenting a model for the comparative analysis of farm organizations, this paper analyzes the farm firm as a complex organization; identifies key structural dimensions of an agricultural production unit; and reviews various organizational perspectives for their utility in understanding and explaining the behavior of farm operations and farm…

  17. Effects of alternate pictorial pathway displays and stereo 3-D presentation on simulated transport landing approach performance

    NASA Astrophysics Data System (ADS)

    Busquets, Anthony M.; Parrish, Russell V.; Williams, Steven P.

    1991-08-01

    `Pathway-in-the-sky'' flight display formats appear to offer exceptional path-control precision for future transport operational environments requiring complex-path approaches. With the conversion from the present instrument landing system (ILS) to the microwave landing system (MLS) within the National Airspace System, complex-path approaches could be used for commercial transport operations to address airport capacity issues. Therefore, the application of `pathway-in-the-sky'' formats to commercial transport operations is being evaluated at various flight display research laboratories. The introduction of true depth cues via stereopsis techniques offers a means of further enhancing these displays. The paper describes research conducted to determine the effectiveness of two candidate pathway formats for landing approach and to investigate the effect of their presentation in stereo versus nonstereo display environments. A real-time piloted simulation experiment comparing performance across these factors in a transport landing-approach task is discussed.

  18. Epidemiological modelling for the assessment of bovine tuberculosis surveillance in the dairy farm network in Emilia-Romagna (Italy).

    PubMed

    Rossi, Gianluigi; De Leo, Giulio A; Pongolini, Stefano; Natalini, Silvano; Vincenzi, Simone; Bolzoni, Luca

    2015-06-01

    Assessing the performance of a surveillance system for infectious diseases of domestic animals is a challenging task for health authorities. Therefore, it is important to assess what strategy is the most effective in identifying the onset of an epidemic and in minimizing the number of infected farms. The aim of the present work was to evaluate the performance of the bovine tuberculosis (bTB) surveillance system in the network of dairy farms in the Emilia-Romagna (ER) Region, Italy. A bTB-free Region since 2007, ER implements an integrated surveillance strategy based on three components, namely routine on-farm tuberculin skin-testing performed every 3 years, tuberculin skin-testing of cattle exchanged between farms, and post-mortem inspection at slaughterhouses. We assessed the effectiveness of surveillance by means of a stochastic network model of both within-farm and between-farm bTB dynamics calibrated on data available for ER dairy farms. Epidemic dynamics were simulated for five scenarios: the current ER surveillance system, a no surveillance scenario that we used as the benchmark to characterize epidemic dynamics, three additional scenarios in which one of the surveillance components was removed at a time so as to outline its significance in detecting the infection. For each scenario we ran Monte Carlo simulations of bTB epidemics following the random introduction of an infected individual in the network. System performances were assessed through the comparative analysis of a number of statistics, including the time required for epidemic detection and the total number of infected farms during the epidemic. Our analysis showed that slaughterhouse inspection is the most effective surveillance component in reducing the time for disease detection, while routine surveillance in reducing the number of multi-farms epidemics. On the other hand, testing exchanged cattle improved the performance of the surveillance system only marginally. Copyright © 2015 The Authors

  19. Aquaculture Farm Facility Loss Management System

    NASA Astrophysics Data System (ADS)

    Choi, Hyung-Rim; Park, Byoung-Kwon; Park, Yong-Sung; Lee, Chang-Sup; Choi, Ki-Nam; Park, Chang-Hyun; Jo, Yong-Hyun; Lee, Byung-Ha

    The loss of aquaculture farm facilities occurring from natural disasters of accidents can cause not only property damage but also marine environmental pollution and vessel safety accidents. When aquaculture farm facilities have been lost to sink down to the bottom of the water, those should be picked up through direct searches but it is difficult to find them because they cannot be visually identified and they are in the sea. In this study, a system that can efficiently manage aquaculture farm facility loss using a new technology IP-RFID will be presented. By attaching IP-Tags to aquaculture farm facilities, this technology enables the transmission of facility information and locations to diverse users in real time through the IPs and through this, the efficiency of aquaculture farm facility management and supervision can be improved and marine environmental pollution can be reduced.

  20. Flow Structure and Turbulence in Wind Farms

    NASA Astrophysics Data System (ADS)

    Stevens, Richard J. A. M.; Meneveau, Charles

    2017-01-01

    Similar to other renewable energy sources, wind energy is characterized by a low power density. Hence, for wind energy to make considerable contributions to the world's overall energy supply, large wind farms (on- and offshore) consisting of arrays of ever larger wind turbines are being envisioned and built. From a fluid mechanics perspective, wind farms encompass turbulent flow phenomena occurring at many spatial and temporal scales. Of particular interest to understanding mean power extraction and fluctuations in wind farms are the scales ranging from 1 to 10 m that comprise the wakes behind individual wind turbines, to motions reaching 100 m to kilometers in scale, inherently associated with the atmospheric boundary layer. In this review, we summarize current understanding of these flow phenomena (particularly mean and second-order statistics) through field studies, wind tunnel experiments, large-eddy simulations, and analytical modeling, emphasizing the most relevant features for wind farm design and operation.

  1. A novel spatial and stochastic model to evaluate the within- and between-farm transmission of classical swine fever virus. I. General concepts and description of the model.

    PubMed

    Martínez-López, B; Ivorra, B; Ramos, A M; Sánchez-Vizcaíno, J M

    2011-01-27

    A new stochastic and spatial model was developed to evaluate the potential spread of classical swine fever virus (CSFV) within- and between-farms, and considering the specific farm-to-farm contact network. Within-farm transmission was simulated using a modified SI model. Between-farm transmission was assumed to occur by direct contacts (i.e. animal movement) and indirect contacts (i.e. local spread, vehicle and person contacts) and considering the spatial location of farms. Control measures dictated by the European legislation (i.e. depopulation of infected farms, movement restriction, zoning, surveillance, contact tracing) were also implemented into the model. Model experimentation was performed using real data from Segovia, one of the provinces with highest density of pigs in Spain, and results were presented using the mean, 95% probability intervals [95% PI] and risk maps. The estimated mean [95% PI] number of infected, quarantined and depopulated farms were 3 [1,17], 23 [0,76] and 115 [0,318], respectively. The duration of the epidemic was 63 [26,177] days and the most important way of transmission was associated with local spread (61.4% of the infections). Results were consistent with the spread of previous CSFV introductions into the study region. The model and results presented here may be useful for the decision making process and for the improvement of the prevention and control programmes for CSFV.

  2. Optimal control of wind-farm boundary layers: effect of turbine response time

    NASA Astrophysics Data System (ADS)

    Munters, Wim; Meyers, Johan

    2016-11-01

    Complex turbine wake interactions play an important role in overall energy extraction in large wind farms. Current control strategies optimize individual turbine power, and lead to significant energy losses in wind farms compared to lone-standing turbines. In recent work, an optimal control framework for dynamic induction control of wind farms and their interaction with the atmospheric boundary layer (ABL) was introduced, with the aim of mitigating such losses. The framework applies a receding horizon methodology, in which the ABL state is modeled through large-eddy simulations. Previously, the framework was applied to both fully-developed and spatially developing wind farms, for which respective energy gains of 16% and 7% were obtained, albeit at the cost of additional turbine loading variability. Here, we quantify the trade-off between increased power extraction and smoothed turbine dynamics by varying the turbine response time in the control framework. We consider simulation cases restricted to underinduction compared to Betz-optimal induction, as well as cases that also allow overinduction. In addition, efforts on replicating optimized power gains with practical controllers are presented. The authors are supported by the ERC (ActiveWindFarms, Grant No.: 306471).

  3. Farm Health and Safety

    MedlinePlus

    ... jobs in the United States. Farms have many health and safety hazards, including Chemicals and pesticides Machinery, ... equipment can also reduce accidents. Occupational Safety and Health Administration

  4. Evaluation of Present-day Aerosols over China Simulated from the Atmospheric Chemistry and Climate Model Intercomparison Project (ACCMIP)

    NASA Astrophysics Data System (ADS)

    Liao, H.; Chang, W.

    2014-12-01

    High concentrations of aerosols over China lead to strong radiative forcing that is important for both regional and global climate. To understand the representation of aerosols in China in current global climate models, we evaluate extensively the simulated present-day aerosol concentrations and aerosol optical depth (AOD) over China from the 12 models that participated in Atmospheric Chemistry & Climate Model Intercomparison Project (ACCMIP), by using ground-based measurements and satellite remote sensing. Ground-based measurements of aerosol concentrations used in this work include those from the China Meteorological Administration (CMA) Atmosphere Watch Network (CAWNET) and the observed fine-mode aerosol concentrations collected from the literature. The ground-based measurements of AOD in China are taken from the AErosol RObotic NETwork (AERONET), the sites with CIMEL sun photometer operated by Institute of Atmospheric Physics, Chinese Academy of Sciences, and from Chinese Sun Hazemeter Network (CSHNET). We find that the ACCMIP models generally underestimate concentrations of all major aerosol species in China. On an annual mean basis, the multi-model mean concentrations of sulfate, nitrate, ammonium, black carbon, and organic carbon are underestimated by 63%, 73%, 54%, 53%, and 59%, respectively. The multi-model mean AOD values show low biases of 20-40% at studied sites in China. The ACCMIP models can reproduce seasonal variation of nitrate but cannot capture well the seasonal variations of other aerosol species. Our analyses indicate that current global models generally underestimate the role of aerosols in China in climate simulations.

  5. Ranking freshwater fish farms for the risk of pathogen introduction and spread.

    PubMed

    Oidtmann, B C; Crane, C N; Thrush, M A; Hill, B J; Peeler, E J

    2011-12-15

    A semi-quantitative model is presented to rank freshwater rainbow trout farms within a country or region with regards to the risk of becoming infected and spreading a specified pathogen. The model was developed to support a risk-based surveillance scheme for notifiable salmonid pathogens. Routes of pathogen introduction and spread were identified through a process of expert consultation in a series of workshops. The routes were combined into themes (e.g. exposure via water, mechanical transmission). Themes were weighted based on expert opinion. Risk factors for each route were scored and combined into a theme score which was adjusted by the weight. The number of sources and consignments were used to assess introduction via live fish movements onto the farm. Biosecurity measures were scored to assess introduction on fomites. Upstream farms, wild fish and processing plants were included in assessing the likelihood of introduction by water. The scores for each theme were combined to give separate risk scores for introduction and spread. A matrix was used to combine these to give an overall risk score. A case study for viral haemorrhagic septicaemia is presented. Nine farms that represent a range of farming practices of rainbow trout farms in England and Wales are used as worked examples of the model. The model is suited to risk rank freshwater salmonid farms which are declared free of the pathogen(s) under consideration. The score allocated to a farm does not equate to a quantitative probability estimate of the farm to become infected or spread infection. Nevertheless, the method provides a transparent approach to ranking farms with regards to pathogen transmission risks. The output of the model at a regional or national level allows the allocation of surveillance effort to be risk based. It also provides fish farms with information on how they can reduce their risk score by improving biosecurity. The framework of the model can be applied to different production

  6. Effect of simulated gastrointestinal digestion on sialic acid and gangliosides present in human milk and infant formulas.

    PubMed

    Lacomba, Ramón; Salcedo, Jaime; Alegría, Amparo; Barberá, Reyes; Hueso, Pablo; Matencio, Esther; Lagarda, M Jesús

    2011-05-25

    The effects of simulated gastrointestinal digestion upon sialic acid and gangliosides in infant and follow-on formulas and human milk, as well as their bioaccessibility, have been evaluated. The gastric stage is the step that causes a greater decrease in sialic acid and ganglioside contents. The intestinal stage only decreases the total and individual contents of gangliosides. After gastrointestinal digestion, neither sialic acid nor gangliosides were found in the nonbioaccessible fraction. The highest bioaccessibility (100 × content in soluble fraction after gastrointestinal digestion/total content) of sialic acid is found in human milk (87%), followed by infant formula (77%) and follow-on formula (16%). In the case of gangliosides, the highest bioaccessibility is present in the follow-on formula (51%), followed by human milk (29%) and infant formula (5%).

  7. Effects of simulated approval-seeking and avoiding on self-disclosure, self-presentation, and interpersonal attraction.

    PubMed

    Pellegrini, R J; Hicks, R A; Meyers-Winton, S

    1978-03-01

    Forty-eight undergraduate women assigned an approval-seeking or approval-avoiding role disclosed significantly more to a male listener (C) than did control Ss given no particular set, with no difference found between seeking and avoiding conditions in intimacy of disclosure. But content analyses indicated that approval-seeking Ss presented themselves significantly more positively, and approval-avoiding Ss significantly more negatively than did controls. These data supported the hypothesis that disclosure may serve as an instrumental affiliative act associated with both interpersonal approach and avoidance motives. The hypothesis that simulated attraction facilitates actual attraction was supported more clearly in analyses of Ss' liking ratings of C than in Ss' ratings of C's attractiveness or desirability as a dating partner. The latter findings are discussed in terms of intimacy implications of the attraction measures used.

  8. Microscopic mechanism on coalescence of the nano-droplets in present non-uniform electric field by molecular dynamics simulations

    NASA Astrophysics Data System (ADS)

    Chen, Qicheng; Ma, Jie; Wang, Bingbing; Zhang, Yingjin

    2016-11-01

    Molecular dynamics simulations are performed to investigate the nano-droplets coalescence process in a non-uniform electric field. Coalescence of droplets driven by dielectrophoresis (DEP) could be observed clearly in a strong electric field. The efficiency of coalescence is remarkably improved about 2 times for non-uniform electric field as much as the efficiency for the uniform electric field. Increasing the gradient of the field, it is found that the DEP force will accelerate the droplets motion of coalescence. But when the gradient of the field increases to a certain degree, the DEP force acting on the droplets presents strongly and rapidly nonlinear increasing and induces the droplets forming the chain structure due to intensively elongating. Moreover, the average operating voltages is much lower in non-uniform electric field.

  9. Visiting People on a Dairy Farm [and] Visiting People on a Dairy Farm: Teacher's Guide.

    ERIC Educational Resources Information Center

    Department of Agriculture, Washington, DC. Office of Governmental and Public Affairs.

    These booklets are designed to present an elementary-level unit that describes a visit to a dairy farm. In a narrative format with many black and white photographs, the student booklet explains some typical activities, such as milking and haying, on the Schwartzbeck dairy farm in Maryland. The booklet is divided into seven parts, each of which can…

  10. Farm Population of the United States: 1973. Current Population Reports, Farm Population.

    ERIC Educational Resources Information Center

    Banks, Vera J.; And Others

    Selected characteristics of the United States' farm population for 1973 are presented. The farm population consists of all persons living in rural territory on places of: (1) 10 or more acres if as much as $50 worth of agricultural products were sold from the place in the reporting year and (2) under 10 acres if as much as $250 worth of…

  11. Modeling velocity space-time correlations in wind farms

    NASA Astrophysics Data System (ADS)

    Lukassen, Laura J.; Stevens, Richard J. A. M.; Meneveau, Charles; Wilczek, Michael

    2016-11-01

    Turbulent fluctuations of wind velocities cause power-output fluctuations in wind farms. The statistics of velocity fluctuations can be described by velocity space-time correlations in the atmospheric boundary layer. In this context, it is important to derive simple physics-based models. The so-called Tennekes-Kraichnan random sweeping hypothesis states that small-scale velocity fluctuations are passively advected by large-scale velocity perturbations in a random fashion. In the present work, this hypothesis is used with an additional mean wind velocity to derive a model for the spatial and temporal decorrelation of velocities in wind farms. It turns out that in the framework of this model, space-time correlations are a convolution of the spatial correlation function with a temporal decorrelation kernel. In this presentation, first results on the comparison to large eddy simulations will be presented and the potential of the approach to characterize power output fluctuations of wind farms will be discussed. Acknowledgements: 'Fellowships for Young Energy Scientists' (YES!) of FOM, the US National Science Foundation Grant IIA 1243482, and support by the Max Planck Society.

  12. Biotechnology on the farm

    SciTech Connect

    Tangley, L.

    1986-10-01

    A new genetically engineered growth hormone promises to boost milk yields for dairy farms. Larger milk yields would worsen economic problems facing dairy farmers especially owners of small farms. The conflicts between new technologies and US agricultural policy are discussed here.

  13. Not Your Family Farm

    ERIC Educational Resources Information Center

    Tenopir, Carol; Baker, Gayle; Grogg, Jill E.

    2007-01-01

    The information industry continues to consolidate, just as agribusiness has consolidated and now dominates farming. Both the family farm and the small information company still exist but are becoming rarer in an age of mergers, acquisitions, and increased economies of scale. Small companies distinguish themselves by high quality, special themes,…

  14. Migrant Farm Workers.

    ERIC Educational Resources Information Center

    Slesinger, Doris P.; Pfeffer, Max J.

    This paper documents migrant farm workers as being among the most persistently underprivileged groups in American society. Migrant farm workers typically receive low wages from irregular employment and live in poverty with access to only substandard housing and inadequate health care. The lack of economic improvement stems from a number of…

  15. Not Your Family Farm

    ERIC Educational Resources Information Center

    Tenopir, Carol; Baker, Gayle; Grogg, Jill E.

    2007-01-01

    The information industry continues to consolidate, just as agribusiness has consolidated and now dominates farming. Both the family farm and the small information company still exist but are becoming rarer in an age of mergers, acquisitions, and increased economies of scale. Small companies distinguish themselves by high quality, special themes,…

  16. Evaluation of drag forcing models for vertical axis wind turbine farms

    NASA Astrophysics Data System (ADS)

    Pierce, Brian; Moin, Parviz; Dabiri, John

    2013-11-01

    Vertical axis wind turbines (VAWTs) have the potential to produce more power per unit area than horizontal axis wind turbines (HAWTs) in a wind farm setting (Kinzel et al. J. Turb. [2012]), but further understanding of the flow physics is required to design such farms. In this study we will model a large wind farm of VAWTs as an array of 100 circular cylinders which will allow a comparison with a laboratory experiment (Craig et al. DFD 2013). The geometric complexity and high Reynolds numbers necessitate phenomenological modeling of the interaction of the turbine with the fluid, which is done through point drag models similar to those found in canopy flow simulations (e.g. Dupont et al. J. Fluid Mech. [2010]). We will present a detailed study of the point drag model performance for flow over one cylinder, providing an evaluation of the model's fidelity as it relates to quantities of interest for the VAWT farm. Next we will present results for flow through the cylinder array, emphasizing validation of the model and insight into VAWT wind farm dynamics. We will also discuss the effect of wall modeling on the calculations, as the Reynolds number of the problem requires the application of wall modeling of the turbulent boundary layer above the ground to keep the cost manageable. Brian Pierce acknowledges support from the Stanford Graduate Fellowship.

  17. Stability Augmentation of Wind Farm using Variable Speed Permanent Magnet Synchronous Generator

    NASA Astrophysics Data System (ADS)

    Rosyadi, Marwan; Muyeen, S. M.; Takahashi, Rion; Tamura, Junji

    This paper presents a new control strategy of variable speed permanent magnet wind generator for stability augmentation of wind farm including fixed speed wind turbine with Induction Generator (IG). A new control scheme is developed for two levels back-to-back converters of Permanent Magnet Synchronous Generator (PMSG), by which both active and reactive powers delivered to the grid can be controlled easily. To avoid the converter damage, the DC link protection controller is also proposed in order to protect the dc link circuit during fault condition. To evaluate the control capability of the proposed controllers, simulations are performed on two model systems composed of wind farms connected to an infinite bus. From transient and steady state analyses by using PSCAD/EMTDC, it is concluded that the proposed control scheme is very effective to improve the stability of wind farm for severe network disturbance and randomly fluctuating wind speed.

  18. A global model simulation of present and future nitrate aerosols and their direct radiative forcing of climate

    NASA Astrophysics Data System (ADS)

    Hauglustaine, D. A.; Balkanski, Y.; Schulz, M.

    2014-03-01

    The ammonia cycle and nitrate particle formation have been introduced in the LMDz-INCA global model. Both fine nitrate particles formation in the accumulation mode and coarse nitrate forming on existing dust and sea-salt particles are considered. The model simulates distributions of nitrates and related species in agreement with previous studies and observations. The calculated present-day total nitrate direct radiative forcing since the pre-industrial is -0.056 W m-2. This forcing has the same magnitude than the forcing associated with organic carbon particles and represents 18% of the sulfate forcing. Fine particles largely dominate the nitrate forcing representing close to 90% of this value. The model has been used to investigate the future changes in nitrates and direct radiative forcing of climate based on snapshot simulations for the four Representative Concentration Pathway (RCP) scenarios and for the 2030, 2050 and 2100 time horizons. Due to a decrease in fossil fuel emissions in the future, the concentrations of most of the species involved in the nitrate-ammonium-sulfate system drop by 2100 except for ammonia which originates from agricultural practices and for which emissions significantly increase in the future. Despite the decrease of nitrate surface levels in Europe and Northern America, the global burden of accumulation mode nitrates increases by up to a factor of 2.6 in 2100. This increase in nitrate in the future arises despite decreasing NOx emissions due to increased availability of ammonia to form ammonium nitrate. The total aerosol direct forcing decreases from its present-day value of -0.234 W m-2 to a range of -0.070 to -0.130 W m-2 in 2100 based on the considered scenario. The direct forcing decreases for all aerosols except for nitrates for which the direct negative forcing increases to a range of -0.060 to -0.115 W m-2 in 2100. Including nitrates in the radiative forcing calculations increases the total direct forcing of aerosols by a

  19. Site-Specific, Climate-Friendly Farming

    NASA Astrophysics Data System (ADS)

    Brown, D. J.; Brooks, E. S.; Eitel, J.; Huggins, D. R.; Painter, K.; Rupp, R.; Smith, J. L.; Stockle, C.; Vierling, L. A.

    2011-12-01

    Of the four most important atmospheric greenhouse gasses (GHG) enriched through human activities, only nitrous oxide (N2O) emissions are due primarily to agriculture. However, reductions in the application of synthetic N fertilizers could have significant negative consequences for a growing world population given the crucial role that these fertilizers have played in cereal yield increases since WWII. Increasing N use efficiency (NUE) through precision management of agricultural N in space and time will therefore play a central role in the reduction of agricultural N2O emissions. Precision N management requires a greater understanding of the spatio-temporal variability of factors supporting N management decisions such as crop yield, water and N availability, utilization and losses. We present an overview of a large, collaborative, multi-disciplinary project designed to improve our basic understanding of nitrogen (N), carbon (C) and water (H2O) spatio-temporal dynamics for wheat-based cropping systems on complex landscapes, and develop management tools to optimize water- and nitrogen-use efficiency for these systems and landscapes. Major components of this project include: (a) cropping systems experiments addressing nitrogen application rate and seeding density for different landscape positions; (b) GHG flux experiments and monitoring; (c) soil microbial genetics and stable isotope analyses to elucidate biochemical pathways for N2O production; (d) proximal soil sensing for construction of detailed soil maps; (e) LiDAR and optical remote sensing for crop growth monitoring; (f) hydrologic experiments, monitoring, and modeling; (g) refining the CropSyst simulation model to estimate biophysical processes and GHG emissions under a variety of management and climatic scenarios; and (h) linking farm-scale enterprise budgets to simulation modeling in order to provide growers with economically viable site-specific climate-friendly farming guidance.

  20. Effect of farm and simulated laboratory cold environmental conditions on the performance and physiological responses of lactating dairy cows supplemented with bovine somatotropin (BST)

    NASA Astrophysics Data System (ADS)

    Becker, B. A.; Johnson, H. D.; Li, R.; Collier, R. J.

    1990-09-01

    A study was conducted to evaluate the effect of bovine somatotropin (BST) supplementation in twelve lactating dairy cows maintained in cold environmental conditions. Six cows were injected daily with 25 mg of BST; the other six were injected with a control vehicle. Cows were maintained under standard dairy management during mid-winter for 30 days. Milk production was recorded twice daily, and blood samples were taken weekly. Animals were then transferred to environmentally controlled chambers and exposed to cycling thermoneutral (15° to 20° C) and cycling cold (-5° to +5° C) temperatures for 10 days in a split-reversal design. Milk production, feed and water intake, body weights and rectal temperatures were monitored. Blood samples were taken on days 1, 3, 5, 8 and 10 of each period and analyzed for plasma triiodothyronine (T3), thyroxine (T4), cortisol, insulin and prolactin. Under farm conditions, BST-treated cows produced 11% more milk than control-treated cows and in environmentally controlled chambers produced 17.4% more milk. No differences due to BST in feed or water intake, body weights or rectal temperatures were found under laboratory conditions. Plasma T3 and insulin increased due to BST treatment while no effect was found on cortisol, prolactin or T4. The results showed that the benefits of BST supplementation in lactating dairy cows were achieved under cold environmental conditions.

  1. Atrazine dissipation and its impact on the microbial communities and community level physiological profiles in a microcosm simulating the biomixture of on-farm biopurification system.

    PubMed

    Tortella, G R; Mella-Herrera, R A; Sousa, D Z; Rubilar, O; Acuña, J J; Briceño, G; Diez, M C

    2013-09-15

    The effects of repeated atrazine application (40 mg a.i.kg(-1)) on its degradation, microbial communities and enzyme activities were studied in a peat based biomixture composed by straw, soil and peat in the volumetric proportions of 2:1:1 that can be used in on-farm biopurification system. Atrazine removal efficiency was high (96%, 78% and 96%) after each atrazine application and did not show a lag phase. Microbial enzyme activities were reduced significantly with atrazine application but rapidly recovered. Microbial diversity obtained by BiologEcoplate was similar after the first and second atrazine application. However, an inhibitory effect was observed after the third application. After each atrazine application, culturable fungi were reduced, but rapidly recovered without significant changes in culturable bacteria and actinomycetes compared to the control. Denaturing gradient gel electrophoresis (DGGE) patterns demonstrated that microbial community structure remained relatively stable in time when compared to the controls. In conclusion, our results demonstrated that after successive ATZ applications, the peat based biomixture had a good degradation capacity. Moreover, microbiological assays demonstrated the robustness of the peat based biomixture from a microbiological point of view to support pesticide degradation.

  2. Climate change and Mediterranean storm tracks: present and future climate simulations of a high-resolution Mediterranean model

    NASA Astrophysics Data System (ADS)

    Hatzaki, M.; Flocas, H. A.; Simmonds, I.; Keay, K.; Giannakopoulos, C.; Brikolas, V.; Kouroutzoglou, J.

    2010-09-01

    A number of studies suggest that cyclone activity over both hemispheres has changed over the second half of the 20th century. General features include a reduction in the number of cyclones but with an increase in the number of more intense cyclones; as well as a poleward shift in the tracks. Moreover, these features are expected to be projected in the future under global warming conditions. The assessment of the future changes of the cyclonic activity as imposed by global warming conditions is very important since these cyclones can be associated with extreme precipitation conditions, severe storms and floods. This is more important for the Mediterranean that has been found to be more vulnerable to climate change. The main objective of the current study is to better understand and assess future changes in the main characteristics of cyclonic tracks in the Mediterranean. The climatology of the cyclonic tracks includes temporal and spatial variations of frequency, and dynamic and kinematic parameters, such as intensity, size, propagation velocity, as well as trend analysis. For this purpose, the ENEA high resolution model is employed, based on PROTHEUS system composed of the RegCM atmospheric regional model and the MITgcm ocean model, coupled through the OASIS3 flux coupler. These model data became available through the EU Project CIRCE which aims to perform, for the first time, climate change projections with a realistic representation of the Mediterranean Sea. Two experiments are employed; a) the EH5OM_20C3M present climate simulation, where the lateral boundary conditions for the atmosphere (1951-2000) are taken from the ECHAM5-MPIOM 20c3m global simulation (run3) included in the IPCC-AR4, and b) the EH5OM_A1B scenario simulation, where the IPCC-AR4 ECHAM5-MPIOM SRESA1B global simulation (run3) has been used for the period 2001-2050. The identification and tracking of cyclones is performed with the aid of the Melbourne University algorithm (MS algorithm

  3. Grid connection of large offshore wind farms using HVDC

    NASA Astrophysics Data System (ADS)

    Xu, Lie; Andersen, Bjarne R.

    2006-07-01

    This article describes the use of high-voltage DC (HVDC) transmission systems for connection of large offshore wind farms using doubly fed induction generators (DFIGs) to the main grid. HVDC systems based on voltage source converters (VSC transmission) and on line-commutated converters (LCC HVDC) are discussed. The article describes proposed system configurations, operating principles and controls for the two technologies. PSCAD/EMTDC simulations are presented to demonstrate the robust performance of the proposed systems during variation of generation and onshore AC fault conditions. Copyright

  4. Off-farm applications of solar energy in agriculture

    SciTech Connect

    Berry, R.E.

    1980-01-01

    Food processing applications make up almost all present off-farm studies of solar energy in agriculture. Research, development and demonstration projects on solar food processing have shown significant progress over the past 3 years. Projects have included computer simulation and mathematical models, hardware and process development for removing moisture from horticultural or animal products, integration of energy conservation with solar energy augmentation in conventional processes, and commercial scale demonstrations. The demonstration projects include solar heated air for drying prunes and raisins, soy beans and onions/garlic; and solar generated steam for orange juice pasteurization. Several new and planned projects hold considerable promise for commerical exploitation in future food processes.

  5. Reducing phosphorus runoff from dairy farms.

    PubMed

    Bosch, Darrell J; Wolfe, Mary Leigh; Knowlton, Katharine F

    2006-01-01

    Phosphorus (P) runoff from manure can lead to eutrophication of surface water and algae growth. This study evaluates the impacts of alternative P reduction practices on dairy farm net returns and on potential P runoff. The P control practices include dairy herd nutrient management, crop nutrient management, and runoff and erosion control. Four farms representative of dairies in the Virginia Shenandoah Valley are simulated including dairies with and without supplementary broiler enterprises and with average and below average land area. A mathematical programming model was developed to predict farm production and net returns and the GLEAMS model was used to predict potential P runoff. The farms are evaluated under four scenarios: Scenario 1, no constraint on P runoff with access to crop nutrient, runoff and erosion control strategies but no access to dairy herd nutrient control strategies; Scenario 2, no constraint on P runoff with access to all crop and dairy herd nutrient control strategies; Scenario 3, constraint on P runoff with access to crop nutrient, runoff and erosion control strategies but no access to dairy herd nutrient control strategies; and Scenario 4, constraint on P runoff with access to all crop and dairy herd nutrient control strategies. Under Scenario 2, the herd nutrient control strategies increase milk output per cow and net returns on both farms and reduce P content of manure and P runoff. Under Scenario 3, limiting P runoff reduces farm returns by 1 and 3% on the average and small farms, respectively. Under Scenario 4, the P runoff constraint is less costly, reducing returns by less than 1% on both farms. Animal nutrient control strategies should be an important part of pollution control policies and programs for livestock intensive watersheds.

  6. The CDF Central Analysis Farm

    SciTech Connect

    Kim, T.H.; Neubauer, M.; Sfiligoi, I.; Weems, L.; Wurthwein, F.; /UC, San Diego

    2004-01-01

    With Run II of the Fermilab Tevatron well underway, many computing challenges inherent to analyzing large volumes of data produced in particle physics research need to be met. We present the computing model within CDF designed to address the physics needs of the collaboration. Particular emphasis is placed on current development of a large O(1000) processor PC cluster at Fermilab serving as the Central Analysis Farm for CDF. Future plans leading toward distributed computing and GRID within CDF are also discussed.

  7. Storing snow for the next winter: Two case studies on the application of snow farming.

    NASA Astrophysics Data System (ADS)

    Grünewald, Thomas; Wolfsperger, Fabian

    2016-04-01

    Snow farming is the conservation of snow during the warm half-year. This means that large piles of snow are formed in spring in order to be conserved over the summer season. Well-insulating materials such as chipped wood are added as surface cover to reduce melting. The aim of snow farming is to provide a "snow guaranty" for autumn or early winter - this means that a specific amount of snow will definitively be available, independent of the weather conditions. The conserved snow can then be used as basis for the preparation of winter sports grounds such as cross-country tracks or ski runs. This helps in the organization of early winter season sport events such as World Cup races or to provide appropriate training conditions for athletes. We present a study on two snow farming projects, one in Davos (Switzerland) and one in the Martell valley of South Tyrol. At both places snow farming has been used for several years. For the summer season 2015, we monitored both snow piles in order to assess the amount of snow conserved. High resolution terrestrial laser scanning was performed to measure snow volumes of the piles at the beginning and at the end of the summer period. Results showed that only 20% to 30 % of the snow mass was lost due to ablation. This mass loss was surprisingly low considering the extremely warm and dry summer. In order to identify the most relevant drivers of snow melt we also present simulations with the sophisticated snow cover models SNOWPACK and Alpine3D. The simulations are driven by meteorological input data recorded in the vicinity of the piles and enable a detailed analysis of the relevant processes controlling the energy balance. The models can be applied to optimize settings for snow farming and to examine the suitability of new locations, configurations or cover material for future snow farming projects.

  8. Interactive 3D-PDF Presentations for the Simulation and Quantification of Extended Endoscopic Endonasal Surgical Approaches.

    PubMed

    Mavar-Haramija, Marija; Prats-Galino, Alberto; Méndez, Juan A Juanes; Puigdelívoll-Sánchez, Anna; de Notaris, Matteo

    2015-10-01

    A three-dimensional (3D) model of the skull base was reconstructed from the pre- and post-dissection head CT images and embedded in a Portable Document Format (PDF) file, which can be opened by freely available software and used offline. The CT images were segmented using a specific 3D software platform for biomedical data, and the resulting 3D geometrical models of anatomical structures were used for dual purpose: to simulate the extended endoscopic endonasal transsphenoidal approaches and to perform the quantitative analysis of the procedures. The analysis consisted of bone removal quantification and the calculation of quantitative parameters (surgical freedom and exposure area) of each procedure. The results are presented in three PDF documents containing JavaScript-based functions. The 3D-PDF files include reconstructions of the nasal structures (nasal septum, vomer, middle turbinates), the bony structures of the anterior skull base and maxillofacial region and partial reconstructions of the optic nerve, the hypoglossal and vidian canals and the internal carotid arteries. Alongside the anatomical model, axial, sagittal and coronal CT images are shown. Interactive 3D presentations were created to explain the surgery and the associated quantification methods step-by-step. The resulting 3D-PDF files allow the user to interact with the model through easily available software, free of charge and in an intuitive manner. The files are available for offline use on a personal computer and no previous specialized knowledge in informatics is required. The documents can be downloaded at http://hdl.handle.net/2445/55224 .

  9. Modeling of Present-Day Atmosphere and Ocean Non-Tidal De-Aliasing Errors for Future Gravity Mission Simulations

    NASA Astrophysics Data System (ADS)

    Bergmann-Wolf, I.; Dobslaw, H.; Mayer-Gürr, T.

    2015-12-01

    A realistically perturbed synthetic de-aliasing model consistent with the updated Earth System Model of the European Space Agency (Dobslaw et al., 2015) is now available for the years 1995 -- 2006. The data-set contains realizations of (i) errors at large spatial scales assessed individually for periods between 10 -- 30, 3 -- 10, and 1 -- 3 days, the S1 atmospheric tide, and sub-diurnal periods; (ii) errors at small spatial scales typically not covered by global models of atmosphere and ocean variability; and (iii) errors due to physical processes not represented in currently available de-aliasing products. The error magnitudes for each of the different frequency bands are derived from a small ensemble of four atmospheric and oceanic models. In order to demonstrate the plausibility of the error magnitudes chosen, we perform a variance component estimation based on daily GRACE normal equations from the ITSG-Grace2014 global gravity field series recently published by the University of Graz. All 12 years of the error model are used to calculate empirical error variance-covariance matrices describing the systematic dependencies of the errors both in time and in space individually for five continental and four oceanic regions, and daily GRACE normal equations are subsequently employed to obtain pre-factors for each of those matrices. For the largest spatial scales up to d/o = 40 and periods longer than 24 h, errors prepared for the updated ESM are found to be largely consistent with noise of a similar stochastic character contained in present-day GRACE solutions. Differences and similarities identified for all of the nine regions considered will be discussed in detail during the presentation.Dobslaw, H., I. Bergmann-Wolf, R. Dill, E. Forootan, V. Klemann, J. Kusche, and I. Sasgen (2015), The updated ESA Earth System Model for future gravity mission simulation studies, J. Geod., doi:10.1007/s00190-014-0787-8.

  10. People on the Farm: Corn and Hog Farming.

    ERIC Educational Resources Information Center

    Department of Agriculture, Washington, DC. Office of Governmental and Public Affairs.

    This booklet provides information on corn and hog farming on a small farm through a profile of a farm family. According to the profile, John and Mary Miller and their three children are a comfortable family operating a corn and hog farm in Iowa. John, the principal farmer, uses a variety of skills in management, veterinary science, soil science,…

  11. White meat-Green farm: case study of Brinson Farms

    USDA-ARS?s Scientific Manuscript database

    Comprehensive on-farm resource utilization and renewable energy generation at the farm scale are not new concepts. However, truly encompassing implementation of these ideals is lacking. Brinson Farms operates 10 commercial broiler houses. The farm generates heat for its houses using biomass boile...

  12. Development and application of process-based simulation models for cotton production: A review of past, present, and future directions

    USDA-ARS?s Scientific Manuscript database

    The development and application of cropping system simulation models for cotton production has a long and rich history, beginning in the southeast United States in the 1960's and now expanded to major cotton production regions globally. This paper briefly reviews the history of cotton simulation mo...

  13. In silico vaccine design based on molecular simulations of rhinovirus chimeras presenting HIV-1 gp41 epitopes.

    PubMed

    Lapelosa, Mauro; Gallicchio, Emilio; Arnold, Gail Ferstandig; Arnold, Eddy; Levy, Ronald M

    2009-01-16

    A cluster of promising epitopes for the development of human immunodeficiency virus (HIV) vaccines is located in the membrane-proximal external region (MPER) of the gp41 subunit of the HIV envelope spike structure. The crystal structure of the peptide corresponding to the so-called ELDKWA epitope (HIV-1 HxB2 gp41 residues 662-668), in complex with the corresponding broadly neutralizing human monoclonal antibody 2F5, provides a target for structure-based vaccine design strategies aimed at finding macromolecular carriers that are able to present this MPER-derived epitope with optimal antigenic activity. To this end, a series of replica exchange molecular dynamics computer simulations was conducted to characterize the distributions of conformations of ELDKWA-based epitopes inserted into a rhinovirus carrier and to identify those with the highest fraction of conformations that are able to bind 2F5. The length, hydrophobic character, and precise site of insertion were found to be critical for achieving structural similarity to the target crystal structure. A construct with a high degree of complementarity to the corresponding determinant region of 2F5 was obtained. This construct was employed to build a high-resolution structural model of the complex between the 2F5 antibody and the chimeric human rhinovirus type 14:HIV-1 ELDKWA virus particle. Additional simulations, which were conducted to study the conformational propensities of the ELDKWA region in solution, confirm the hypothesis that the ELDKWA region of gp41 is highly flexible and capable of assuming helical conformations (as in the postfusion helical bundle structure) and beta-turn conformations (as in the complex with the 2F5 antibody). These results also suggest that the ELDKWA epitope can be involved in intramolecular--and likely intermolecular--hydrophobic interactions. This tendency offers an explanation for the observation that mutations decreasing the hydrophobic character of the MPER in many cases result

  14. Hazards of Farming

    PubMed Central

    Guilfoyle, John

    1992-01-01

    Farming is the most dangerous occupation in the industrialized world. Children, in particular, are at high risk for injury and disability. There is ample scope to improve this situation. Parents are the most important group to be educated. Emergency response services in rural areas are sometimes unable to provide optimum care for victims. Better surveillance methods need to be in place, both to gather information and to evaluate strategies aimed at prevention. Farm safety needs to be higher on the agenda for farmers, farm organizations, government, and health care professionals. PMID:21221275

  15. On-farm biosecurity as perceived by professionals visiting Swedish farms.

    PubMed

    Nöremark, Maria; Sternberg-Lewerin, Susanna

    2014-05-09

    On-farm biosecurity is an important part of disease prevention and control, this applies to live animal contacts as well as indirect contacts e.g. via professionals visiting farms in their work. The objectives of this study were to investigate how professionals visiting animal farms in Sweden in their daily work perceive the on-farm conditions for biosecurity, the factors that influence their own biosecurity routines and what they describe as obstacles for biosecurity. Suggestions for improvements were also asked for. Questionnaires were distributed to professionals visiting farms in their daily work; veterinarians, livestock hauliers, artificial insemination technicians, animal welfare inspectors and cattle hoof trimmers. The sample was a convenience sample, based on accessibility to registers or collaboration with organisations distributing the questionnaire. Respondents were asked about the availability of certain biosecurity conditions related to farm visits, e.g. if facilities for hand washing were available, how important different factors were for their own routines and, through open ended questions, to describe obstacles and suggestions for improvement. After data cleaning, there were responses from 368 persons. There was a difference in the proportion of visited farms reported to have certain biosecurity measures in place related to animal species present on the farm. In general, visited pig farms had a higher proportion of biosecurity measures in place, whereas the conditions were poorer on sheep and goat farms and horse farms. There were also differences between the visitor categories; the perceived conditions for biosecurity varied between the groups, e.g. livestock hauliers did not have access to hand washing facilities as often as veterinarians did. In all groups, a majority of the respondents perceived obstacles for on-farm biosecurity, among veterinarians 66% perceived that there were obstacles. Many of the reported obstacles related to the very

  16. On-farm biosecurity as perceived by professionals visiting Swedish farms

    PubMed Central

    2014-01-01

    Background On-farm biosecurity is an important part of disease prevention and control, this applies to live animal contacts as well as indirect contacts e.g. via professionals visiting farms in their work. The objectives of this study were to investigate how professionals visiting animal farms in Sweden in their daily work perceive the on-farm conditions for biosecurity, the factors that influence their own biosecurity routines and what they describe as obstacles for biosecurity. Suggestions for improvements were also asked for. Questionnaires were distributed to professionals visiting farms in their daily work; veterinarians, livestock hauliers, artificial insemination technicians, animal welfare inspectors and cattle hoof trimmers. The sample was a convenience sample, based on accessibility to registers or collaboration with organisations distributing the questionnaire. Respondents were asked about the availability of certain biosecurity conditions related to farm visits, e.g. if facilities for hand washing were available, how important different factors were for their own routines and, through open ended questions, to describe obstacles and suggestions for improvement. Results After data cleaning, there were responses from 368 persons. There was a difference in the proportion of visited farms reported to have certain biosecurity measures in place related to animal species present on the farm. In general, visited pig farms had a higher proportion of biosecurity measures in place, whereas the conditions were poorer on sheep and goat farms and horse farms. There were also differences between the visitor categories; the perceived conditions for biosecurity varied between the groups, e.g. livestock hauliers did not have access to hand washing facilities as often as veterinarians did. In all groups, a majority of the respondents perceived obstacles for on-farm biosecurity, among veterinarians 66% perceived that there were obstacles. Many of the reported obstacles

  17. The Development of a Virtual Farm for Applications in Elementary Science Education

    ERIC Educational Resources Information Center

    Tarng, Wernhuar; Chang, Mei-Yu; Ou, Kuo-Liang; Yu, Kein-Fu; Hsieh, Kuen-Rong

    2012-01-01

    The goal of this study is to develop a virtual farm for educational applications. Users can play the role of a farmer by planting vegetables and raising poultry on the virtual farm to observe their growth through online learning activities. The virtual farm possesses educational and entertaining functions, and it is designed by simulating the real…

  18. The Development of a Virtual Farm for Applications in Elementary Science Education

    ERIC Educational Resources Information Center

    Tarng, Wernhuar; Chang, Mei-Yu; Ou, Kuo-Liang; Yu, Kein-Fu; Hsieh, Kuen-Rong

    2012-01-01

    The goal of this study is to develop a virtual farm for educational applications. Users can play the role of a farmer by planting vegetables and raising poultry on the virtual farm to observe their growth through online learning activities. The virtual farm possesses educational and entertaining functions, and it is designed by simulating the real…

  19. Spatiotemporal structure of wind farm-atmospheric boundary layer interactions

    NASA Astrophysics Data System (ADS)

    Cervarich, Matthew; Baidya Roy, Somnath; Zhou, Liming

    2013-04-01

    Wind power is currently one of the fastest growing energy sources in the world. Most of the growth is in the utility sector consisting of large wind farms with numerous industrial-scale wind turbines. Wind turbines act as a sink of mean kinetic energy and a source of turbulent kinetic energy in the atmospheric boundary layer (ABL). In doing so, they modify the ABL profiles and land-atmosphere exchanges of energy, momentum, mass and moisture. This project explores theses interactions using remote sensing data and numerical model simulations. The domain is central Texas where 4 of the world's largest wind farms are located. A companion study of seasonally-averaged Land Surface Temperature data from the Moderate Resolution Imaging Spectroradiometer (MODIS) on TERRA and AQUA satellites shows a warming signal at night and a mixed cooling/warming signal during the daytime within the wind farms. In the present study, wind farm-ABL interactions are simulated with the Weather Research and Forecasting (WRF) model. The simulations show that the model is capable of replicating the observed signal in land surface temperature. Moreover, similar warming/cooling effect, up to 1C, was observed in seasonal mean 2m air temperature as well. Further analysis show that enhanced turbulent mixing in the rotor wakes is responsible for the impacts on 2m and surface air temperatures. The mixing is due to 2 reasons: (i) turbulent momentum transport to compensate the momentum deficit in the wakes of the turbines and (ii) turbulence generated due to motion of turbine rotors. Turbulent mixing also alters vertical profiles of moisture. Changes in land-atmosphere temperature and moisture gradient and increase in turbulent mixing leads to more than 10% change in seasonal mean surface sensible and latent heat flux. Given the current installed capacity and the projected installation across the world, wind farms are likely becoming a major driver of anthropogenic land use change on Earth. Hence

  20. T-Opt: A 3D Monte Carlo simulation for light delivery design in photodynamic therapy (Conference Presentation)

    NASA Astrophysics Data System (ADS)

    Honda, Norihiro; Hazama, Hisanao; Awazu, Kunio

    2017-02-01

    The interstitial photodynamic therapy (iPDT) with 5-aminolevulinic acid (5-ALA) is a safe and feasible treatment modality of malignant glioblastoma. In order to cover the tumour volume, the exact position of the light diffusers within the lesion is needed to decide precisely. The aim of this study is the development of evaluation method of treatment volume with 3D Monte Carlo simulation for iPDT using 5-ALA. Monte Carlo simulations of fluence rate were performed using the optical properties of the brain tissue infiltrated by tumor cells and normal tissue. 3-D Monte Carlo simulation was used to calculate the position of the light diffusers within the lesion and light transport. The fluence rate near the diffuser was maximum and decreased exponentially with distance. The simulation can calculate the amount of singlet oxygen generated by PDT. In order to increase the accuracy of simulation results, the parameter for simulation includes the quantum yield of singlet oxygen generation, the accumulated concentration of photosensitizer within tissue, fluence rate, molar extinction coefficient at the wavelength of excitation light. The simulation is useful for evaluation of treatment region of iPDT with 5-ALA.

  1. Stochastic dynamic simulation modeling including multitrait genetics to estimate genetic, technical, and financial consequences of dairy farm reproduction and selection strategies

    USDA-ARS?s Scientific Manuscript database

    The objective of this study was to develop a daily stochastic dynamic dairy simulation model which included multi-trait genetics, and to evaluate the effects of various reproduction and selection strategies on the genetic, technical and financial performance of a dairy herd. The 12 correlated geneti...

  2. Summary of: Simulating the Value of Concentrating Solar Power with Thermal Energy Storage in a Production Cost Model (Presentation)

    SciTech Connect

    Denholm, P.; Hummon, M.

    2013-02-01

    Concentrating solar power (CSP) deployed with thermal energy storage (TES) provides a dispatchable source of renewable energy. The value of CSP with TES, as with other potential generation resources, needs to be established using traditional utility planning tools. Production cost models, which simulate the operation of grid, are often used to estimate the operational value of different generation mixes. CSP with TES has historically had limited analysis in commercial production simulations. This document describes the implementation of CSP with TES in a commercial production cost model. It also describes the simulation of grid operations with CSP in a test system consisting of two balancing areas located primarily in Colorado.

  3. A global model simulation of present and future nitrate aerosols and their direct radiative forcing of climate

    NASA Astrophysics Data System (ADS)

    Hauglustaine, D. A.; Balkanski, Y.; Schulz, M.

    2014-10-01

    The ammonia cycle and nitrate particle formation are introduced into the LMDz-INCA (Laboratoire de Météorologie Dynamique, version 4 - INteraction with Chemistry and Aerosols, version 3) global model. An important aspect of this new model is that both fine nitrate particle formation in the accumulation mode and coarse nitrate forming on existing dust and sea-salt particles are considered. The model simulates distributions of nitrates and related species in agreement with previous studies and observations. The calculated present-day total nitrate direct radiative forcing since the pre-industrial is -0.056 W m-2. This forcing corresponds to 18% of the sulfate forcing. Fine particles largely dominate the nitrate forcing, representing close to 90% of this value. The model has been used to investigate the future changes in nitrates and direct radiative forcing of climate based on snapshot simulations for the four representative concentration pathway (RCP) scenarios and for the 2030, 2050, and 2100 time horizons. Due to a decrease in fossil fuel emissions in the future, the concentration of most of the species involved in the nitrate-ammonium-sulfate system drop by 2100 except for ammonia, which originates from agricultural practices and for which emissions significantly increase in the future. Despite the decrease of nitrate surface levels in Europe and North America, the global burden of accumulation mode nitrates increases by up to a factor of 2.6 in 2100. This increase in ammonium nitrate in the future arises despite decreasing NOx emissions due to increased availability of ammonia to form ammonium nitrate. The total aerosol direct forcing decreases from its present-day value of -0.234 W m-2 to a range of -0.070 to -0.130 W m-2 in 2100 based on the considered scenario. The direct forcing decreases for all aerosols except for nitrates, for which the direct negative forcing increases to a range of -0.060 to -0.115 W m-2 in 2100. Including nitrates in the radiative

  4. Farm and Family Management Program.

    ERIC Educational Resources Information Center

    Iowa State Univ. of Science and Technology, Ames. Cooperative Extension Service.

    This teacher's guide contains four units for the farm and family management program, a three-year educational program through which farm families have the opportunity to participate in group and individualized instruction. The program is intended to help provide basic farm and home management information to farm families to meet the changes of the…

  5. Agriculture: Organic Farming

    EPA Pesticide Factsheets

    Organic Farming - Organically grown food is food grown and processed using no synthetic fertilizers or pesticides. Pesticides derived from natural sources (such as biological pesticides) may be used in producing organically grown food.

  6. Tifft Farm Nature Preserve.

    ERIC Educational Resources Information Center

    Benjamin, Thomas B.; Gannon, David J.

    1980-01-01

    Described are the creation, development, activities, and programs of Tifft Farm, a 264-acre nature preserve and environmental education center in Buffalo, New York, constructed on a sanitary landfill. (BT)

  7. Tifft Farm Nature Preserve.

    ERIC Educational Resources Information Center

    Benjamin, Thomas B.; Gannon, David J.

    1980-01-01

    Described are the creation, development, activities, and programs of Tifft Farm, a 264-acre nature preserve and environmental education center in Buffalo, New York, constructed on a sanitary landfill. (BT)

  8. Farm Financial Standards.

    PubMed

    McGrann, J M

    1995-07-01

    The Farm Financial Standards were developed by a national effort to encourage standardization. Standardization includes financial statement formats, terminology, and calculations for measuring financial position and format. Comparative analysis and education efforts are enhanced greatly by standardization. The Standardization Performance Analysis (SPA) system was developed on the basis of the performance standards for beef cattle and sheep enterprises. This article summarizes the Farm Financial Standards and illustrates the calculations with a worksheet.

  9. Atlantic salmon populations invaded by farmed escapees: quantifying genetic introgression with a Bayesian approach and SNPs

    PubMed Central

    2013-01-01

    Background Many native Atlantic salmon populations have been invaded by domesticated escapees for three decades or longer. However, thus far, the cumulative level of gene-flow that has occurred from farmed to wild salmon has not been reported for any native Atlantic salmon population. The aim of the present study was to investigate temporal genetic stability in native populations, and, quantify gene-flow from farmed salmon that caused genetic changes where they were observed. This was achieved by genotyping historical and contemporary samples from 20 populations covering all of Norway with recently identified single nucleotide polymorphism markers that are collectively diagnostic for farmed and wild salmon. These analyses were combined with analysis of farmed salmon and implementation of Approximate Bayesian computation based simulations. Results Five of the populations displayed statistically significant temporal genetic changes. All five of these populations became more similar to a pool of farmed fish with time, strongly suggesting introgression of farmed fish as the primary cause. The remaining 15 populations displayed weak or non-significant temporal genetic changes. Estimated introgression of farmed fish ranged from 2-47% per population using approximate Bayesian computation. Thus, some populations exhibited high degrees of farmed salmon introgression while others were more or less unaffected. The observed frequency of escapees in each population was moderately correlated with estimated introgression per population R2 = 0.47 P < 0.001. Genetic isolation by distance existed within the historical and contemporary data sets, however, the among-population level of divergence decreased with time. Conclusions This is the first study to quantify cumulative introgression of farmed salmon in any native Atlantic salmon population. The estimations demonstrate that the level of introgression has been population-specific, and that the level of introgression is not

  10. First comparison of LES of an offshore wind turbine wake with dual-Doppler lidar measurement in the offshore wind farm "alpha ventus"

    NASA Astrophysics Data System (ADS)

    Vollmer, L.; Trabucchi, D.; Witha, B.; van Dooren, M.; Trujillo, J. J.; Schneemann, J.; Kühn, M.

    2014-12-01

    The planning of offshore wind farms is still tainted with high risks due to unknown power losses and a higher level of fatigue loads due to wake effects. Recently, Large Eddy Simulations (LES) are more and more used for simulating offshore wind turbine wakes as they resolve the atmospheric turbulence as well as the wake turbulence.However, for an application of LES wind fields to assess offshore wind farm flow a proper validation with measured data is necessary.Several methods have been investigated at the University of Oldenburg to compare LES wind fields and lidar measurements. In this study we apply one of these methods to validate wake simulations of a single wake of a 5MW wind turbine in the German offshore wind farm "alpha ventus" with processed dual-Doppler lidar measurements in the same wind farm.The simulations are performed with the LES model PALM, which has been enhanced by two different approaches of actuator models to simulate the wake of single wind turbines and the interaction of wakes in wind farms. Effects of tower and nacelle are regarded as well as simple turbine control mechanisms. The simulations are initialized with comparable atmospheric conditions as during the time of lidar operation by using measurements from the adjacent meteorological mast FINO 1.Plan Position Indicator (PPI) measurements have been performed with two long-range wind lidars installed at different opposing platforms at the border of the wind farm. A Cartesian grid was overlapped to the scanned region and a dual-Doppler algorithm was applied in order to estimate the horizontal stationary wind field on the grid nodes. To our knowledge, the presented study is one of the first validations of LES wake simulations with lidar measurements and first which validates offshore LES wake simulations with 2D lidar data.

  11. Implications of within-farm transmission for network dynamics: Consequences for the spread of avian influenza

    PubMed Central

    Nickbakhsh, Sema; Matthews, Louise; Dent, Jennifer E.; Innocent, Giles T.; Arnold, Mark E.; Reid, Stuart W.J.; Kao, Rowland R.

    2013-01-01

    The importance of considering coupled interactions across multiple population scales has not previously been studied for highly pathogenic avian influenza (HPAI) in the British commercial poultry industry. By simulating the within-flock transmission of HPAI using a deterministic S-E-I-R model, and by incorporating an additional environmental class representing infectious faeces, we tracked the build-up of infectious faeces within a poultry house over time. A measure of the transmission risk (TR) was computed for each farm by linking the amount of infectious faeces present each day of an outbreak with data describing the daily on-farm visit schedules for a major British catching company. Larger flocks tended to have greater levels of these catching-team visits. However, where density-dependent contact was assumed, faster outbreak detection (according to an assumed mortality threshold) led to a decreased opportunity for catching-team visits to coincide with an outbreak. For this reason, maximum TR-levels were found for mid-range flock sizes (~25,000–35,000 birds). When assessing all factors simultaneously using multivariable linear regression on the simulated outputs, those related to the pattern of catching-team visits had the largest effect on TR, with the most important movement-related factor depending on the mode of transmission. Using social network analysis on a further database to inform a measure of between-farm connectivity, we identified a large fraction of farms (28%) that had both a high TR and a high potential impact at the between farm level. Our results have counter-intuitive implications for between-farm spread that could not be predicted based on flock size alone, and together with further knowledge of the relative importance of transmission risk and impact, could have implications for improved targeting of control measures. PMID:23746799

  12. Sustainability evaluation of different systems for sea cucumber ( Apostichopus japonicus) farming based on emergy theory

    NASA Astrophysics Data System (ADS)

    Wang, Guodong; Dong, Shuanglin; Tian, Xiangli; Gao, Qinfeng; Wang, Fang

    2015-06-01

    Emergy analysis is effective for analyzing ecological economic systems. However, the accuracy of the approach is affected by the diversity of economic level, meteorological and hydrological parameters in different regions. The present study evaluated the economic benefits, environmental impact, and sustainability of indoor, semi-intensive and extensive farming systems of sea cucumber ( Apostichopus japonicus) in the same region. The results showed that A. japonicus indoor farming system was high in input and output (yield) whereas pond extensive farming system was low in input and output. The output/input ratio of indoor farming system was lower than that of pond extensive farming system, and the output/input ratio of semi-intensive farming system fell in between them. The environmental loading ratio of A. japonicus extensive farming system was lower than that of indoor farming system. In addition, the emergy yield and emergy exchange ratios, and emergy sustainability and emergy indexes for sustainable development were higher in extensive farming system than those in indoor farming system. These results indicated that the current extensive farming system exerted fewer negative influences on the environment, made more efficient use of available resources, and met more sustainable development requirements than the indoor farming system. A. japonicus farming systems showed more emergy benefits than fish farming systems. The pond farming systems of A. japonicus exploited more free local environmental resources for production, caused less potential pressure on the local environment, and achieved higher sustainability than indoor farming system.

  13. Simulation

    NASA Technical Reports Server (NTRS)

    Foster, F.; Randle, R.

    1984-01-01

    The application of flight simulation in regional airline training programs is discussed. Specifically, the use of simulation in cockpit resources management training (CRMT) is investigated. The availability of simulation resources is explored and the simulator disadvantages and advantages are cited. Problems with simulator specification, procurement, validation and use that have plagued the major air carriers over several decades are addressed.

  14. Development of a bio-relevant dissolution test device simulating mechanical aspects present in the fed stomach.

    PubMed

    Koziolek, Mirko; Görke, Kristin; Neumann, Marco; Garbacz, Grzegorz; Weitschies, Werner

    2014-06-16

    A novel bio-relevant in vitro dissolution device was designed to mimic intragastric conditions after food intake paying particular consideration to mechanical aspects: the Fed Stomach Model (FSM). The FSM represents a fully computer-controlled dynamic flow-through system, in which dosage forms are hosted in so-called gastric vessels. Dosage form movement profiles as well as pressures can be simulated in a physiologically relevant manner. This proof-of-concept study aimed at the investigation of the effects of individual parameters and complex test programs on the drug delivery behavior of diclofenac sodium bilayer extended release tablets. Magnetic marker monitoring experiments demonstrated the applicability of the FSM to simulate intragastric movement velocities of solid oral dosage forms equivalent to in vivo data. Dissolution experiments revealed the relevance of all simulated parameters (i.e. pressure, dosage form movement and pump rate). Moreover, three different test scenarios with test programs specific for fundus, antrum and gastric emptying considered the variability of intragastric transit of solid oral dosage forms after food intake and were confirmed to be reasonable. Dissolution rates were low under conditions specific for fundus owing to low shear stresses. In contrast, higher amounts of the drug were released under high stress conditions simulating antral transit and gastric emptying. Concluding, the FSM can be a valuable tool for bio-relevant dissolution testing due to its potential of precise and reproducible simulation of mechanical parameters characteristic for the fed stomach.

  15. SIMULATION EXERCISES IN AREA TRAINING. PAPER PRESENTED IN A SYMPOSIUM AT THE 1965 ARMY HUMAN FACTORS RESEARCH AND DEVELOPMENT CONFERENCE.

    ERIC Educational Resources Information Center

    STEWART, EDWARD C.

    SPECIAL TECHNIQUES AND CONTENT ARE BEING DEVELOPED TO SUPPLEMENT CURRENT AREA TRAINING PROGRAMS. SIMULATION WAS CHOSEN AS THE TECHNIQUE, AND EXERCISES WERE DEVELOPED WHOSE CONTENT EMPHASIZED THE AMERICAN CULTURE AND THE FOREIGN, HOST CULTURE. THESE EVOLVED AS A CONFRONTATION BETWEEN AMERICAN CULTURAL ASSUMPTIONS AND VALUES AND A CONTRASTING SET,…

  16. Spring melt ponds drive Arctic September ice at past, present and future climates in coupled climate simulation

    NASA Astrophysics Data System (ADS)

    Schroeder, David; Feltham, Danny; Rae, Jamie; Flocco, Daniela; Ridley, Jeff; Blockley, Edd

    2016-04-01

    Stand-alone sea ice simulations with a physical based melt pond model reveal a strong correlation between the simulated spring pond fraction and the observed as well as simulated September sea ice extent for the period 1979 to 2014. This is explained by a positive feedback mechanism: more ponds reduce the albedo; a lower albedo causes more melting; more melting increases pond fraction. This feedback process is a potential reason for the acceleration of Arctic sea ice decrease in the last decade and the failure of many climate models (without an implicit pond model) to simulate the observed decrease. We implemented the Los Alamos sea ice model CICE 5 including our physical based melt pond model into the latest version of the Hadley Centre coupled climate model, HadGEM3. The model surface shortwave radiation scheme has been adjusted to account for pond fraction and depth. We performed three 55-year HadGEM3 simulations with constant external forcing for the years 1985, 2010 and 2035. In all three simulations we find a strong correlation between the April/May pond fraction and the September sea ice extent with correlation coefficients R1985 = -0.86, R2010 = -0.83 and R2035 = -0.79. Based on the correlation we can perform forecasts with remarkable skill values of S1985 = 0.50, S2010 = 0.36 and S2035 = 0.40. We calculate the skill as S = 1 - σferr2/ σref2, where σref2 is the variance of the de-trended climatology and σferr2 the forecast error variance. Altogether our three simulations cover a large range of September sea ice extent from maximum values of 8.5 million km2 for the 1985 run down to 1.5 million km2 for the 2035 run. We demonstrate that spring melt ponds are an important driver for summer ice melt and the consequent minimum ice extent for current and future climate conditions.

  17. Perceptions About the Present and Future of Surgical Simulation: A National Study of Mixed Qualitative and Quantitative Methodology.

    PubMed

    Yiasemidou, Marina; Glassman, Daniel; Tomlinson, James; Song, David; Gough, Michael J

    Assess expert opinion on the current and future role of simulation in surgical education. Expert opinion was sought through an externally validated questionnaire that was disseminated electronically. Heads of Schools of Surgery (HoS) (and deputies) and Training Program Directors (TPD) (and deputies). Simulation was considered a good training tool (HoS: 15/15, TPD: 21/21). The concept that simulation is useful mostly to novices and for basic skills acquisition was rejected (HoS: 15/15, TPDs: 21/21; HoS: 13/15, TPDs: 18/21). Further, simulation is considered suitable for teaching nontechnical skills (HoS: 13/15, TPDs: 20/21) and re-enacting stressful situations (HoS: 14/15, TPDs: 15/21). Most respondents also felt that education centers should be formally accredited (HoS: 12/15, TPDs: 16/21) and that consultant mentors should be appointed by every trust (HoS: 12/15, TPDs: 19/21). In contrast, there were mixed views on its use for trainee assessment (HoS: 6/15, TPDs: 14/21) and whether it should be compulsory (HoS: 8/15, TPDs: 11/21). The use of simulation for the acquirement of both technical and nontechnical skills is strongly supported while views on other applications (e.g., assessment) are conflicting. Further, the need for center accreditation and supervised, consultant-led teaching is highlighted. Copyright © 2016 Association of Program Directors in Surgery. Published by Elsevier Inc. All rights reserved.

  18. WE-D-BRF-01: FEATURED PRESENTATION - Investigating Particle Track Structures Using Fluorescent Nuclear Track Detectors and Monte Carlo Simulations

    SciTech Connect

    Dowdell, S; Paganetti, H; Schuemann, J; Greilich, S; Zimmerman, F; Evans, C

    2014-06-15

    Purpose: To report on the efforts funded by the AAPM seed funding grant to develop the basis for fluorescent nuclear track detector (FNTD) based radiobiological experiments in combination with dedicated Monte Carlo simulations (MCS) on the nanometer scale. Methods: Two confocal microscopes were utilized in this study. Two FNTD samples were used to find the optimal microscope settings, one FNTD irradiated with 11.1 MeV/u Gold ions and one irradiated with 428.77 MeV/u Carbon ions. The first sample provided a brightly luminescent central track while the latter is used to test the capabilities to observe secondary electrons. MCS were performed using TOPAS beta9 version, layered on top of Geant4.9.6p02. Two sets of simulations were performed, one with the Geant4-DNA physics list and approximating the FNTDs by water, a second set using the Penelope physics list in a water-approximated FNTD and a aluminum-oxide FNTD. Results: Within the first half of the funding period, we have successfully established readout capabilities of FNTDs at our institute. Due to technical limitations, our microscope setup is significantly different from the approach implemented at the DKFZ, Germany. However, we can clearly reconstruct Carbon tracks in 3D with electron track resolution of 200 nm. A second microscope with superior readout capabilities will be tested in the second half of the funding period, we expect an improvement in signal to background ratio with the same the resolution.We have successfully simulated tracks in FNTDs. The more accurate Geant4-DNA track simulations can be used to reconstruct the track energy from the size and brightness of the observed tracks. Conclusion: We have achieved the goals set in the seed funding proposal: the setup of FNTD readout and simulation capabilities. We will work on improving the readout resolution to validate our MCS track structures down to the nanometer scales.

  19. CPS and the Fermilab farms

    SciTech Connect

    Fausey, M.R.

    1992-06-01

    Cooperative Processes Software (CPS) is a parallel programming toolkit developed at the Fermi National Accelerator Laboratory. It is the most recent product in an evolution of systems aimed at finding a cost-effective solution to the enormous computing requirements in experimental high energy physics. Parallel programs written with CPS are large-grained, which means that the parallelism occurs at the subroutine level, rather than at the traditional single line of code level. This fits the requirements of high energy physics applications, such as event reconstruction, or detector simulations, quite well. It also satisfies the requirements of applications in many other fields. One example is in the pharmaceutical industry. In the field of computational chemistry, the process of drug design may be accelerated with this approach. CPS programs run as a collection of processes distributed over many computers. CPS currently supports a mixture of heterogeneous UNIX-based workstations which communicate over networks with TCP/IR CPS is most suited for jobs with relatively low I/O requirements compared to CPU. The CPS toolkit supports message passing remote subroutine calls, process synchronization, bulk data transfers, and a mechanism called process queues, by which one process can find another which has reached a particular state. The CPS software supports both batch processing and computer center operations. The system is currently running in production mode on two farms of processors at Fermilab. One farm consists of approximately 90 IBM RS/6000 model 320 workstations, and the other has 85 Silicon Graphics 4D/35 workstations. This paper first briefly describes the history of parallel processing at Fermilab which lead to the development of CPS. Then the CPS software and the CPS Batch queueing system are described. Finally, the experiences of using CPS in production on the Fermilab processor farms are described.

  20. Rainfall simulation experiments and Water Drop Penetration Time measurements shed light on the impact of water repellency on soils under organic farming management in Eastern Spain

    NASA Astrophysics Data System (ADS)

    Cerdà, Artemi; González, Óscar; León, Javier; Jordán, Antonio

    2015-04-01

    Water repellency is a well-know soil property since the research of professor Stefan Helmut Doerr recovered and powered the research developed by professor DeBano (Atanassova and Doerr, 2011; ; Jordán et al., 2011; Bodí et al., 2012; González Peñaloza et al., 2012 Bodí et al., 2013; García Moreno et al., 2013; Jordán et al., 2013; Badía-Villas et al., 2014; Jordán et al., 2013; Jiménez Morillo et al., 2015). However, little is known about the impact of water repellency in surface runoff generation, although usually is accepted that when more soil water repellent is a soil, higher will be the surface runoff discharge (Stoff et al., 2011; Madsen et al., 2011; León et al., 2013; Lozano et al., 2013; Mataix-Solera et al., 2013; Santos et al., 2015). And the impact of the water repellency and then the higher surface wash discharge can trigger high erosion rates (Kröpfl et al., 2013; Mandal and Sharda 2013; Zhao et al., 2013). However these relationships were not demonstrated as the most water repellent soils are the one with high organic contents, and those soils do not have soil losses, probably due to the high infiltration rates due to the macropore flow. Rainfall simulation experiments can shed light in the runoff generation mechanism as they can control the rainfall intensity (Bodí et al., 2012; Iserloh et al., 2012; Iserloh et al., 2013), and inform about the main mechanism of the soil erosion process Cerdà and Jurgensen, 2011; Daugherty et al., 2011; Podwojewski et al., 2011; Dunkerley, 2012; Garel et al., 2012; Jouquet et al., 2012; Kibet et al., 2013; Butzen et al., 2014; Ma et al., 2014; Martínez Murillo et al., 2013). To determine the relationship between surface runoff generated under simulated rainfall (Cerdà, 1988a; 1988b; Cerdà et al., 1998; Ziadat and Taimeh, 2013) with a small rainfall simulator (0.25 m2) and water repellency measurements with the Water Drop Penetration time methods were done (Bodí et al., 2012). The results show that

  1. IMPACT ASSESSMENT OF EXISTING VADOSE ZONE CONTAMINATION AT THE HANFORD SITE SX TANK FARM

    SciTech Connect

    KHALEEL R

    2007-11-01

    The USDOE has initiated an impact assessment of existing vadose zone contamination at the Hanford Site SX tank farm in southeastern Washington State. The assessment followed the Resource Conservation and Recovery Act (RCRA) Corrective Action process to address the impacts of past tank waste releases to the vadose zone at the single-shell tank farm. Numerical models were developed that consider the extent of contamination presently within the vadose zone and predict contaminant movement through the vadose zone to groundwater. The transport of representative mobile (technetium-99) and immobile (cesium-137) constituents was evaluated in modeling. The model considered the accelerated movement of moisture around and beneath single-shell tanks that is attributed to bare, gravel surfaces resulting from the construction of the underground storage tanks. Infiltration, possibly nearing 100 mm yr{sup -1}, is further amplified in the tank farm because of the umbrella effect created by percolating moisture being diverted by the impermeable, sloping surface of the large, 24-m-diameter, buried tank domes. For both the base case (no-action alternative) simulation and a simulation that considered placement of an interim surface barrier to minimize infiltration, predicted, groundwater concentrations for technetium-99 at the SX tank farm boundary were exceedingly high, on the order of 10{sup 6} pCi L{sup -1}. The predicted concentrations are, however, somewhat conservative because of our use of two-dimensional modeling for a three-dimensional problem. A series of simulations were performed, using recharge rates of 50, 30, and 10 mm yr{sup -1}, and compared to the basecase(100 mm yr{sup -1}) results. As expected, lowering meteoric recharge delayed peak arrival times and reduced peak concentrations at the tank farm boundary.

  2. Impact Assessment of Existing Vadose Zone Contamination at the Hanford Site SX Tank Farm

    SciTech Connect

    Khaleel, Raziuddin; White, Mark D.; Oostrom, Martinus; Wood, Marcus I.; Mann, Frederick M.; Kristofzski, John G.

    2007-11-01

    The USDOE has initiated an impact assessment of existing vadose zone contamination at the Hanford Site SX tank farm in southeastern Washington State. The assessment followed the Resource Conservation and Recovery Act (RCRA) Corrective Action process to address the impacts of past tank waste releases to the vadose zone at the single-shell tank farm. Numerical models were developed that consider the extent of contamination presently within the vadose zone and predict contaminant movement through the vadose zone to groundwater. The transport of representative mobile (technetium-99) and immobile (cesium-137) constituents was evaluated in modeling. The model considered the accelerated movement of moisture around and beneath single-shell tanks that is attributed to bare, gravel surfaces resulting from the construction of the underground storage tanks. Infiltration, possibly nearing 100 mm yr–1, is further amplified in the tank farm because of the umbrella effect created by percolating moisture being diverted by the impermeable, sloping surface of the large, 24-m-diameter, buried tank domes. For both the base case (no-action alternative) simulation and a simulation that considered placement of an interim surface barrier to minimize infiltration, predicted groundwater concentrations for technetium-99 at the SX tank farm boundary were exceedingly high, on the order of 106 pCi L–1. The predicted concentrations are, however, somewhat conservative because of our use of two-dimensional modeling for a three-dimensional problem. A series of simulations were performed, using recharge rates of 50, 30, and 10 mm yr–1, and compared to the base case (100 mm yr–1) results. As expected, lowering meteoric recharge delayed peak arrival times and reduced peak concentrations at the tank farm boundary.

  3. DairyWise, a whole-farm dairy model.

    PubMed

    Schils, R L M; de Haan, M H A; Hemmer, J G A; van den Pol-van Dasselaar, A; de Boer, J A; Evers, A G; Holshof, G; van Middelkoop, J C; Zom, R L G

    2007-11-01

    A whole-farm dairy model was developed and evaluated. The DairyWise model is an empirical model that simulated technical, environmental, and financial processes on a dairy farm. The central component is the FeedSupply model that balanced the herd requirements, as generated by the DairyHerd model, and the supply of homegrown feeds, as generated by the crop models for grassland and corn silage. The output of the FeedSupply model was used as input for several technical, environmental, and economic submodels. The submodels simulated a range of farm aspects such as nitrogen and phosphorus cycling, nitrate leaching, ammonia emissions, greenhouse gas emissions, energy use, and a financial farm budget. The final output was a farm plan describing all material and nutrient flows and the consequences on the environment and economy. Evaluation of DairyWise was performed with 2 data sets consisting of 29 dairy farms. The evaluation showed that DairyWise was able to simulate gross margin, concentrate intake, nitrogen surplus, nitrate concentration in ground water, and crop yields. The variance accounted for ranged from 37 to 84%, and the mean differences between modeled and observed values varied between -5 to +3% per set of farms. We conclude that DairyWise is a powerful tool for integrated scenario development and evaluation for scientists, policy makers, extension workers, teachers and farmers.

  4. Dynamic Flow Model for Real-Time Application in Wind Farm Control

    NASA Astrophysics Data System (ADS)

    Rott, Andreas; Boersma, Sjoerd; van Wingerden, Jan-Willem; Kühn, Martin

    2017-05-01

    For short-term power predictions and estimations of the available power during curtailment of a wind farm, it is necessary to consider the flow dynamics and aerodynamic interactions of the turbines. In this paper, a control-oriented dynamic two-dimensional wind farm model is introduced that aims to incorporate real-time measurements such as flow velocities at turbine locations to estimate the ambient wind farm flow. The model is intended to derive flow predictions for real-time applications. Since fully resolved computational fluid dynamics are too CPU-intensive for such a task, the dynamic model presented in this paper relies on an approximation of the flow equations in a two-dimensional framework. A semi-Lagrangian advection scheme and a step-wise flow solver together offer fast calculation speed, which scales linearly with the number of grid points. In order to emulate effects of realistic three-dimensional wind farm flow, a relaxation of the two-dimensional continuity equation is presented. Furthermore, with little extra computational expense, additional dynamic state variables for various possible applications can be propagated along the wind flow. For instance, a dynamic confidence parameter can provide estimations of the accuracy of flow predictions, while a turbulence parameter adds the possibility to estimate wake induced loads on downstream turbines. In order to demonstrate the performance and validity of the new model it is compared with other models. At first a two turbine reference case is compared with a steady-state model and secondly with results obtained by the dynamic wind farm flow model WFSim. Finally a small wind farm is simulated in order to show the computational scaling of the model.

  5. Presented at the AGARD Conference on Piloted Simulation Effectiveness, held in Brussels, Belgium on 14-17 October 1991 (L’Efficacite de la Simulation Pilotee)

    DTIC Science & Technology

    1992-02-01

    AD-A253 007 0 AGARD- C - AIDI9OR MRU O EOSPAC RESEARM DEVEOMN 7 RUE ANCELLE 92200 NEUILLY SUR SEINE FRANCE Piloted Simulation Effectiveness...authors. Published February 1992 Copyright C AGARD 1992 AIll Rightq ,rsenc,,d o ISBN 92-835-01656-1 Dam Printed by Specialised Printing Services...Panel Chairman: ICA J.-M. Duc Deputy Chairman: Prof. L.M.B. da Costa Campos Directeur Pavilhio de Maquinas Affaires Internationales Instituto Superior

  6. How fast is Arctic climate really changing? An insight from recent past, present day and near future coupled model simulations

    NASA Astrophysics Data System (ADS)

    Koenigk, Torben; Brodeau, Laurent

    2016-04-01

    Three quasi-equilibrium simulations using constant greenhouse gas forcing corresponding to years 2000, 2015 and 2030 have been performed with the global coupled model EC-Earth in order to analyze recent past and possible near future changes in the Arctic climate. The model simulations indicate an accelerated warming and ice extent reduction in the Arctic in near future conditions compared to the recent past. Both Arctic warming and sea ice reduction are closely linked to the increase of ocean heat transport into the Arctic, particularly through the Barents Sea Opening. Decadal variations of Arctic sea ice extent and ice volume are of the same order of magnitude as the observed ice extent reductions in the last 30 years and are dominated by the variability of the ocean heat transports through the Barents Sea Opening and the Bering Strait. Despite a general warming of mid and high northern latitudes, a substantial cooling is found in the subpolar gyre of the North Atlantic in the near future simulation. This cooling is related to a strong reduction in the AMOC, which is mainly caused by reduced deep water formation in the Labrador Sea. The observed trend towards a more negative phase of the North Atlantic Oscillation (NAO) and the observed linkage between autumn Arctic ice variations and NAO are reproduced in our model simulations for selected 30-year periods but are not robust over longer time periods. This indicates that the observed linkages between ice and NAO might not be robust in reality either, and that the observational time period is still too short to reliably separate the trend from the natural variability.

  7. The CDF Analysis Farm

    NASA Astrophysics Data System (ADS)

    Casarsa, M.; Hsu, S.-C.; Lipeles, E.; Neubauer, M.; Sarkar, S.; Sfiligoi, I.; Würthwein, F.

    2005-10-01

    Since the beginning of Run II in 2001 the Fermilab Tevatron has been delivering proton-antiproton collisions to CDF with a steadily increasing performance. By the end of Run II up to 8 fb-1 of integrated luminosity are expected to be available on tape. In order to provide the CDF Collaboration members with adequate computing resources for analyzing those data, a globally distributed pool of dedicated PC farms has been commissioned and is currently being successfully deployed. This paper describes the main features of the CDF Analysis Farm with particular attention to the user perspective. The last part is devoted to a brief overview of the more relevant technical details on the farm implementation and, finally, the future developments toward its integration in the GRID framework are outlined.

  8. Impact of model developments on present and future simulations of permafrost in a global land-surface model

    NASA Astrophysics Data System (ADS)

    Chadburn, S. E.; Burke, E. J.; Essery, R. L. H.; Boike, J.; Langer, M.; Heikenfeld, M.; Cox, P. M.; Friedlingstein, P.

    2015-03-01

    There is a large amount of organic carbon stored in permafrost in the northern high latitudes, which may become vulnerable to microbial decomposition under future climate warming. In order to estimate this potential carbon-climate feedback it is necessary to correctly simulate the physical dynamics of permafrost within global Earth System Models (ESMs) and to determine the rate at which it will thaw. Additional new processes within JULES, the land surface scheme of the UK ESM (UKESM), include a representation of organic soils, moss and bedrock, and a modification to the snow scheme. The impact of a higher vertical soil resolution and deeper soil column is also considered. Evaluation against a large group of sites shows the annual cycle of soil temperatures is approximately 25 % too large in the standard JULES version, but this error is corrected by the model improvements, in particular by deeper soil, organic soils, moss and the modified snow scheme. Comparing with active layer monitoring sites shows that the active layer is on average just over 1 m too deep in the standard model version, and this bias is reduced by 70 cm in the improved version. Increasing the soil vertical resolution allows the full range of active layer depths to be simulated, where by contrast with a poorly resolved soil, at least 50% of the permafrost area has a maximum thaw depth at the centre of the bottom soil layer. Thus all the model modifications are seen to improve the permafrost simulations. Historical permafrost area corresponds fairly well to observations in all simulations, covering an area between 14-19 million km2. Simulations under two future climate scenarios show a reduced sensitivity of permafrost degradation to temperature, with the near-surface permafrost lost per degree of warming reduced from 1.5 million km2 °C-1 in the standard version of JULES to between 1.1 and 1.2 million km2 °C-1 in the new model version. However, the near-surface permafrost area is still projected

  9. Impact of model developments on present and future simulations of permafrost in a global land-surface model

    NASA Astrophysics Data System (ADS)

    Chadburn, S. E.; Burke, E. J.; Essery, R. L. H.; Boike, J.; Langer, M.; Heikenfeld, M.; Cox, P. M.; Friedlingstein, P.

    2015-08-01

    There is a large amount of organic carbon stored in permafrost in the northern high latitudes, which may become vulnerable to microbial decomposition under future climate warming. In order to estimate this potential carbon-climate feedback it is necessary to correctly simulate the physical dynamics of permafrost within global Earth system models (ESMs) and to determine the rate at which it will thaw. Additional new processes within JULES, the land-surface scheme of the UK ESM (UKESM), include a representation of organic soils, moss and bedrock and a modification to the snow scheme; the sensitivity of permafrost to these new developments is investigated in this study. The impact of a higher vertical soil resolution and deeper soil column is also considered. Evaluation against a large group of sites shows the annual cycle of soil temperatures is approximately 25 % too large in the standard JULES version, but this error is corrected by the model improvements, in particular by deeper soil, organic soils, moss and the modified snow scheme. A comparison with active layer monitoring sites shows that the active layer is on average just over 1 m too deep in the standard model version, and this bias is reduced by 70 cm in the improved version. Increasing the soil vertical resolution allows the full range of active layer depths to be simulated; by contrast, with a poorly resolved soil at least 50 % of the permafrost area has a maximum thaw depth at the centre of the bottom soil layer. Thus all the model modifications are seen to improve the permafrost simulations. Historical permafrost area corresponds fairly well to observations in all simulations, covering an area between 14 and 19 million km2. Simulations under two future climate scenarios show a reduced sensitivity of permafrost degradation to temperature, with the near-surface permafrost loss per degree of warming reduced from 1.5 million km2 °C-1 in the standard version of JULES to between 1.1 and 1.2 million km2 °C-1

  10. The Farm Process Version 2 (FMP2) for MODFLOW-2005 - Modifications and Upgrades to FMP1

    USGS Publications Warehouse

    Schmid, Wolfgang; Hanson, R.T.

    2009-01-01

    The ability to dynamically simulate the integrated supply-and-demand components of irrigated agricultural is needed to thoroughly understand the interrelation between surface water and groundwater flow in areas where the water-use by vegetation is an important component of the water budget. To meet this need, the computer program Farm Process (FMP1) was updated and refined for use with the U.S. Geological Survey's MODFLOW-2005 groundwater-flow model, and is referred to as MF2005-FMP2. The updated program allows the simulation, analysis, and management of nearly all components of human and natural water use. MF2005-FMP2 represents a complete hydrologic model that fully links the movement and use of groundwater, surface water, and imported water for water consumption of irrigated agriculture, but also of urban use, and of natural vegetation. Supply and demand components of water use are analyzed under demand-driven and supply-constrained conditions. From large- to small-scale settings, the MF2005-FMP2 has the unique set of capabilities to simulate and analyze historical, present, and future conditions. MF2005-FMP2 facilitates the analysis of agricultural water use where little data is available for pumpage, land use, or agricultural information. The features presented in this new version of FMP2 along with the linkages to the Streamflow Routing (SFR), Multi-Node Well (MNW), and Unsaturated Zone Flow (UZF) Packages prevents mass loss to an open system and helps to account for 'all of the water everywhere and all of the time'. The first version, FMP1 for MODFLOW-2000, is limited to (a) transpiration uptake from unsaturated root zones, (b) on-farm efficiency defined solely by farm and not by crop type, (c) a simulation of water use and returnflows related only to irrigated agriculture and not also to non-irrigated vegetation, (d) a definition of consumptive use as potential crop evapotranspiration, (e) percolation being instantly recharged to the uppermost active

  11. Long Island Solar Farm

    SciTech Connect

    Anders, R.

    2013-05-01

    The Long Island Solar Farm (LISF) is a remarkable success story, whereby very different interest groups found a way to capitalize on unusual circumstances to develop a mutually beneficial source of renewable energy. The uniqueness of the circumstances that were necessary to develop the Long Island Solar Farm make it very difficult to replicate. The project is, however, an unparalleled resource for solar energy research, which will greatly inform large-scale PV solar development in the East. Lastly, the LISF is a superb model for the process by which the project developed and the innovation and leadership shown by the different players.

  12. Farm animal biotechnology.

    PubMed

    Bulfield, G

    2000-01-01

    As we enter a new millennium, the research with the greatest likely impact on both the biological sciences and the biotechnology industry will be the sequencing of the human and other genomes. Widespread interest in farm animal genomics as a method for identifying genes controlling commercially important traits started only a decade ago. Although the genomics of farm animals was relatively late to arrive on the scene compared with the genomics of crop plants, it has the advantage of being able to access the enormous amount of human genome information.

  13. Farming fit? Dispelling the Australian agrarian myth

    PubMed Central

    2011-01-01

    Background Rural Australians face a higher mental health and lifestyle disease burden (obesity, diabetes and cardiovascular disease) than their urban counterparts. Our ongoing research reveals that the Australian farming community has even poorer physical and mental health outcomes than rural averages. In particular, farm men and women have high rates of overweightness, obesity, abdominal adiposity, high blood pressure and psychological distress when compared against Australian averages. Within our farming cohort we observed a significant association between psychological distress and obesity, abdominal adiposity and body fat percentage in the farming population. Presentation of hypothesis This paper presents a hypothesis based on preliminary data obtained from an ongoing study that could potentially explain the complex correlation between obesity, psychological distress and physical activity among a farming population. We posit that spasmodic physical activity, changing farm practices and climate variability induce prolonged stress in farmers. This increases systemic cortisol that, in turn, promotes abdominal adiposity and weight gain. Testing the hypothesis The hypothesis will be tested by anthropometric, biochemical and psychological analysis matched against systemic cortisol levels and the physical activity of the subjects. Implications of the hypothesis tested Previous studies indicate that farming populations have elevated rates of psychological distress and high rates of suicide. Australian farmers have recently experienced challenging climatic conditions including prolonged drought, floods and cyclones. Through our interactions and through the media it is not uncommon for farmers to describe the effect of this long-term stress with feelings of 'defeat'. By gaining a greater understanding of the role cortisol and physical activity have on mental and physical health we may positively impact the current rates of psychological distress in farmers. Trial

  14. An Examination of Hired Farm Workers on Iowa Farms.

    ERIC Educational Resources Information Center

    Heitmann, Kenneth Harry

    Characteristics of farms, farmers and hired laborers were examined to provide a basis for decisions about labor needs on Iowa farms. The study was limited to year-round farm jobs in large-sized enterprises to develop some knowledge of working conditions, renumerations, and skills which will be required in the future. A 3-phase study was conducted…

  15. Farm Mapping to Assist, Protect, and Prepare Emergency Responders: Farm MAPPER.

    PubMed

    Reyes, Iris; Rollins, Tami; Mahnke, Andrea; Kadolph, Christopher; Minor, Gerald; Keifer, Matthew

    2014-01-01

    Responders such as firefighters and emergency medical technicians who respond to farm emergencies often face complex and unknown environments. They may encounter hazards such as fuels, solvents, pesticides, caustics, and exploding gas storage cylinders. Responders may be unaware of dirt roads within the farm that can expedite their arrival at critical sites or snow-covered manure pits that act as hidden hazards. A response to a farm, unless guided by someone familiar with the operation, may present a risk to responders and post a challenge in locating the victim. This project explored the use of a Web-based farm-mapping application optimized for tablets and accessible via easily accessible on-site matrix barcodes, or quick response codes (QR codes), to provide emergency responders with hazard and resource information to agricultural operations. Secured portals were developed for both farmers and responders, allowing both parties to populate and customize farm maps with icons. Data were stored online and linked to QR codes attached to mailbox posts where emergency responders may read them with a mobile device. Mock responses were conducted on dairy farms to test QR code linking efficacy, Web site security, and field usability. Findings from farmer usability tests showed willingness to enter data as well as ease of Web site navigation and data entry even with farmers who had limited computer knowledge. Usability tests with emergency responders showed ease of QR code connectivity to the farm maps and ease of Web site navigation. Further research is needed to improve data security as well as assess the program's applicability to nonfarm environments and integration with existing emergency response systems. The next phases of this project will expand the program for regional and national use, develop QR code-linked, Web-based extrication guidance for farm machinery for victim entrapment rescue, and create QR code-linked online training videos and materials for limited

  16. Single-particle detection of virus simulants under microfluidic flow with two-dimensional photonic crystals (Conference Presentation)

    NASA Astrophysics Data System (ADS)

    Miller, Benjamin L.; Baker, James E.; Sriram, Rashmi

    2017-05-01

    Because of their compatibility with standard CMOS fabrication, small footprint, and exceptional sensitivity, Two-Dimensional Photonic Crystals (2D PhCs) have been posited as attractive components for the development of real-time integrated photonic virus sensors. While detection of single virus-sized particles by 2D PhCs has been demonstrated, specific recognition of a virus simulant under conditions relevant to sensor use (including aqueous solution and microfluidic flow) has remained an unsolved challenge. This talk will describe the design and testing of a W1 waveguide-coupled 2D PhC in the context of addressing that challenge.

  17. Overview Presentation

    NASA Technical Reports Server (NTRS)

    Lytle, John

    2001-01-01

    This report provides an overview presentation of the 2000 NPSS (Numerical Propulsion System Simulation) Review and Planning Meeting. Topics include: 1) a background of the program; 2) 1999 Industry Feedback; 3) FY00 Status, including resource distribution and major accomplishments; 4) FY01 Major Milestones; and 5) Future direction for the program. Specifically, simulation environment/production software and NPSS CORBA Security Development are discussed.

  18. Urban Farm Business Plan Handbook

    EPA Pesticide Factsheets

    The Urban Farm Business Plan Handbook (this document) provides guidance for developing a business plan for the startup and operation of an urban farm. It focuses on food and non-food related cultivated agriculture.

  19. Simulations of the HDO and H2O-18 atmospheric cycles using the NASA GISS general circulation model - The seasonal cycle for present-day conditions

    NASA Technical Reports Server (NTRS)

    Jouzel, J.; Russell, G. L.; Suozzo, R. J.; Koster, R. D.; White, J. W. C.

    1987-01-01

    The cycles of the water isotopic species (HDO and H2O-18) have been incorporated into the NASA Goddard Institute for Space Studies atmospheric general circulation model (GCM). The results of a three-year simulation for present-day conditions are discussed, with special emphasis on the comparison between predicted and observed isotopic distributions for both the seasonal and annual time scales. The observed seasonal cycles are generally well simulated. For the annual scale the observed linear relationship between delta O-18 and the surface temperature at middle and high latitudes, as well as the absence of any correlation between these fields in tropical and equatorial regions, are properly obeyed by the GCM simulation. In the tropical and equatorial regions the delta O-18 patterns for both observations and the GCM are influenced by the amount of rainfall. There is excellent agreement between the simulated and observed delta D-delta O-18 relationship throughout the world.

  20. Evaluating expansion strategies for startup European Union dairy farm businesses.

    PubMed

    McDonald, R; Shalloo, L; Pierce, K M; Horan, B

    2013-06-01

    A stochastic whole-farm simulation model was used to examine alternative strategies for new entrant dairy farmers to grow and develop dairy farm businesses in the context of European Union (EU) milk quota abolition in 2015. Six alternative strategies were compared: remain static, natural growth expansion, waiting until after EU milk quota abolition to expand, a full-scale expansion strategy without milk quotas and not incurring super levy penalties, a full-scale expansion strategy with milk quotas and incurring super levy penalties, and once-a-day milking until EU milk quota abolition, followed by full-scale expansion. Each discrete whole farm investment strategy was evaluated over a 15-yr period (2013-2027) using multiple financial stability and risk indicators, including overall discounted farm business profitability, net worth change, return on investment, and financial risk. The results of this study indicate that, although associated with increased risk, dairy farm expansion will ensure the future profitability of the farm business. Within the context of EU milk quotas until 2015, the most attractive expansion strategy is to increase cow numbers while avoiding super levy fines using once-a-day milking techniques, increasing to the full capacity of the dairy farm once milk quotas are removed. In contrast, the results also indicate that dairy farms that remain static will experience a significant reduction in farm profitability in the coming year due to production cost inflation. Cash flow deficits were observed during the initial year of expansion and, therefore, rapidly expanding dairy farm businesses require a significant cash reserve to alleviate business risk during the initial year of expansion. The results of this analysis also indicate that dairy farm businesses that expand using lower cost capital investments and avoid milk quota super levy fines significantly reduce the financial risks associated with expansion. Copyright © 2013 American Dairy Science

  1. Transient climate simulations of the deglaciation 21-9 thousand years before present; PMIP4 Core experiment design and boundary conditions

    NASA Astrophysics Data System (ADS)

    Ivanovic, R. F.; Gregoire, L. J.; Kageyama, M.; Roche, D. M.; Valdes, P. J.; Burke, A.; Drummond, R.; Peltier, W. R.; Tarasov, L.

    2015-10-01

    The last deglaciation, which marked the transition between the last glacial and present interglacial periods, was punctuated by a series of rapid (centennial and decadal) climate changes. Numerical climate models are useful for investigating mechanisms that underpin the events, especially now that some of the complex models can be run for multiple millennia. We have set up a Paleoclimate Modelling Intercomparison Project (PMIP) working group to coordinate efforts to run transient simulations of the last deglaciation, and to facilitate the dissemination of expertise between modellers and those engaged with reconstructing the climate of the last 21 thousand years. Here, we present the design of a coordinated Core simulation over the period 21-9 thousand years before present (ka) with time varying orbital forcing, greenhouse gases, ice sheets, and other geographical changes. A choice of two ice sheet reconstructions is given, but no ice sheet or iceberg meltwater should be prescribed in the Core simulation. Additional focussed simulations will also be coordinated on an ad-hoc basis by the working group, for example to investigate the effect of ice sheet and iceberg meltwater, and the uncertainty in other forcings. Some of these focussed simulations will focus on shorter durations around specific events to allow the more computationally expensive models to take part.

  2. Cryptosporidiois in farmed animals

    USDA-ARS?s Scientific Manuscript database

    The disease, cryptosporidiosis, has been identified in humans and animals in 106 countries and has been attributed to 26 species of Cryptosporidium and several additional genotypes. The specific farmed animals discussed in this chapter include cattle, sheep, goats, water buffaloes, deer, camels, lla...

  3. Tox Town Farm

    MedlinePlus

    ... download the Flash player. City Farm Town Port US Southwest U.S. National Library of Medicine 8600 Rockville Pike Bethesda, MD 20894 1-888-FIND-NLM National Institutes of Health Department of Health & Human Services ... Updates Contact Us: tehip@teh.nlm.nih.gov Copyright Privacy Freedom ...

  4. FARM LABOR MARKET DEVELOPMENT.

    ERIC Educational Resources Information Center

    Department of Labor, Washington, DC.

    PART ONE OF THE REPORT CONSISTED OF AN ANALYSIS OF TRENDS BETWEEN 1960 AND 1961 IN WAGES OF UNITED STATES FARM WORKERS IN MAJOR AREAS USING MEXICAN NATIONALS. THE DATA WERE DERIVED FROM PREVAILING-WAGE REPORTS RECEIVED BY THE BUREAU OF EMPLOYMENT SECURITY FROM AFFILIATED STATE EMPLOYMENT SECURITY AGENCIES. THE SURVEY RATES WERE USED BY THE…

  5. Terraces and contour farming

    USDA-ARS?s Scientific Manuscript database

    Terraces are earthen embankments constructed across the prevailing field land slope. They have been used in differing forms for thousands of years in an attempt to protect steep land slopes from runoff induced erosion. Contour farming, where tillage and planting create ridges and furrows at nearly...

  6. Shrimp Farms, Ecuador

    NASA Image and Video Library

    2006-05-15

    In many parts of the world, wetlands are being converted to shrimp ponds in order to farm these crustaceans for food and sale. One example is on the west coast of Ecuador, south of Guayaquil. This image was acquired by NASA Terra spacecraft.

  7. FARM LABOR MARKET DEVELOPMENT.

    ERIC Educational Resources Information Center

    Department of Labor, Washington, DC.

    PART ONE OF THE REPORT CONSISTED OF AN ANALYSIS OF TRENDS BETWEEN 1960 AND 1961 IN WAGES OF UNITED STATES FARM WORKERS IN MAJOR AREAS USING MEXICAN NATIONALS. THE DATA WERE DERIVED FROM PREVAILING-WAGE REPORTS RECEIVED BY THE BUREAU OF EMPLOYMENT SECURITY FROM AFFILIATED STATE EMPLOYMENT SECURITY AGENCIES. THE SURVEY RATES WERE USED BY THE…

  8. High School Education of the Farm Population in Selected States. Bulletin, 1925, No. 6

    ERIC Educational Resources Information Center

    Windes, E. E.

    1925-01-01

    This bulletin attempts to present: (1) the comparative extent to which farm and nonfarm groups are receiving public secondary education; and (2) the relation of significant factors concerning high schools and the farm population to participation in secondary education by farm children. The data here presented must be regarded as incomplete but…

  9. Content Priorities for Farm Mechanics

    ERIC Educational Resources Information Center

    Knotts, C. Don; Webb, Earl S.

    1974-01-01

    Fifty successful young Texas farmers evaluated agricultural mechanics skills (in the broad areas of farm power and machinery, farm shop, farm electricity, buildings and conveniences, and soil and water management) in terms of their importance. Teachers can use the findings to plan course content relevant to their students' needs. (AJ)

  10. Content Priorities for Farm Mechanics

    ERIC Educational Resources Information Center

    Knotts, C. Don; Webb, Earl S.

    1974-01-01

    Fifty successful young Texas farmers evaluated agricultural mechanics skills (in the broad areas of farm power and machinery, farm shop, farm electricity, buildings and conveniences, and soil and water management) in terms of their importance. Teachers can use the findings to plan course content relevant to their students' needs. (AJ)

  11. Farm Education at Stony Kill.

    ERIC Educational Resources Information Center

    Parisio, Richard

    1986-01-01

    Describes typical winter farm lessons for students visiting Stony Kill Farm Environmental Education Center located 70 miles north of New York City: butter and corncake making, soil erosion experiments, dissecting and growing seeds. Emphasizes major theme of conservation of farmland from destructive farming practices and careless development. (NEC)

  12. Farm Education at Stony Kill.

    ERIC Educational Resources Information Center

    Parisio, Richard

    1986-01-01

    Describes typical winter farm lessons for students visiting Stony Kill Farm Environmental Education Center located 70 miles north of New York City: butter and corncake making, soil erosion experiments, dissecting and growing seeds. Emphasizes major theme of conservation of farmland from destructive farming practices and careless development. (NEC)

  13. Three methods of presenting flight vector information in a head-up display during simulated STOL approaches

    NASA Technical Reports Server (NTRS)

    Dwyer, J. H., III; Palmer, E. A., III

    1975-01-01

    A simulator study was conducted to determine the usefulness of adding flight path vector symbology to a head-up display designed to improve glide-slope tracking performance during steep 7.5 deg visual approaches in STOL aircraft. All displays included a fixed attitude symbol, a pitch- and roll-stabilized horizon bar, and a glide-slope reference bar parallel to and 7.5 deg below the horizon bar. The displays differed with respect to the flight-path marker (FPM) symbol: display 1 had no FPM symbol; display 2 had an air-referenced FPM, and display 3 had a ground-referenced FPM. No differences between displays 1 and 2 were found on any of the performance measures. Display 3 was found to decrease height error in the early part of the approach and to reduce descent rate variation over the entire approach. Two measures of workload did not indicate any differences between the displays.

  14. Farming fit? Dispelling the Australian agrarian myth.

    PubMed

    Brumby, Susan; Chandrasekara, Ananda; McCoombe, Scott; Kremer, Peter; Lewandowski, Paul

    2011-03-30

    Rural Australians face a higher mental health and lifestyle disease burden (obesity, diabetes and cardiovascular disease) than their urban counterparts. Our ongoing research reveals that the Australian farming community has even poorer physical and mental health outcomes than rural averages. In particular, farm men and women have high rates of overweightness, obesity, abdominal adiposity, high blood pressure and psychological distress when compared against Australian averages. Within our farming cohort we observed a significant association between psychological distress and obesity, abdominal adiposity and body fat percentage in the farming population. This paper presents a hypothesis based on preliminary data obtained from an ongoing study that could potentially explain the complex correlation between obesity, psychological distress and physical activity among a farming population. We posit that spasmodic physical activity, changing farm practices and climate variability induce prolonged stress in farmers. This increases systemic cortisol that, in turn, promotes abdominal adiposity and weight gain. The hypothesis will be tested by anthropometric, biochemical and psychological analysis matched against systemic cortisol levels and the physical activity of the subjects. IMPLICATIONS OF THE HYPOTHESIS TESTED: Previous studies indicate that farming populations have elevated rates of psychological distress and high rates of suicide. Australian farmers have recently experienced challenging climatic conditions including prolonged drought, floods and cyclones. Through our interactions and through the media it is not uncommon for farmers to describe the effect of this long-term stress with feelings of 'defeat'. By gaining a greater understanding of the role cortisol and physical activity have on mental and physical health we may positively impact the current rates of psychological distress in farmers. ACTRN12610000827033.

  15. Validation of the present day annual cycle in heavy precipitation over the British Islands simulated by 14 RCMs

    NASA Astrophysics Data System (ADS)

    Schindler, A.; Maraun, D.; Luterbacher, J.

    2012-09-01

    The representation of the annual cycle of heavy daily precipitation events across the United Kingdom within 14 regional climate models (RCMs) and the European observation data set (E-OBS) over the 1961-2000 period is investigated. We model extreme precipitation as an inhomogeneous Poisson process with a non-stationary threshold and use a sinusoidal model for the location and scale parameter of the corresponding generalized extreme value distribution and a constant shape parameter. First we fit the statistical model to the UK Met Office 5 km gridded precipitation data set (UKMO). Second the statistical model is fitted to 14 reanalysis driven 25 km resolution RCMs from the ENSEMBLES project and to E-OBS. The resulting characteristics from the RCMs and from E-OBS are compared with those from UKMO. We study the peak time of the annual cycle of the monthly return levels, the relative amplitude of their annual cycle and the relative bias of their absolute values. We show that the performance of the RCMs depends strongly on the region. The RCMs show deficits in modeling the characteristics of the annual cycle, especially in modeling its relative amplitude and mainly in Eastern England. However the peak time of the annual cycle is adequately simulated by most RCMs. E-OBS exhibits considerable biases in the absolute values of all monthly return levels, but the relative amplitude and the phase of the annual cycle of heavy precipitation are well represented. Our results imply that studies which rely on the explicit annual cycle of simulated heavy precipitation should be carefully considered.

  16. Occurrence and genotypes of Campylobacter in broiler flocks, other farm animals, and the environment during several rearing periods on selected poultry farms.

    PubMed

    Zweifel, Claudio; Scheu, Kathrin Daniela; Keel, Michaela; Renggli, Franz; Stephan, Roger

    2008-07-15

    On 15 Swiss poultry farms, broiler flocks, other farm animals, and the environment were examined during consecutive rearing periods to investigate the occurrence and genetic diversity of Campylobacter. Of the 5154 collected samples, 311 (6%) from 14 farms were Campylobacter positive by culture. Amongst the positive samples, 228 tested positive for Campylobacter jejuni and 92 for Campylobacter coli. Positive samples originated from broilers, the broiler houses, cattle, pigs, bantams, laying hens, a horse, and a mouse. Feed, litter, flies, and the supply air to the broiler house tested negative. By flagellin gene typing (fla-RFLP) and pulsed-field gel electrophoresis (PFGE), 917 Campylobacter isolates were genotyped. Additionally, amplified fragment length polymorphism (AFLP) analysis was performed on 15 assorted strains. On eight farms, matching genotypes were isolated from broiler flocks and other farm animals: Certain genotypes from cattle (farms H, K, L, and M), pigs (farms D and P), or laying hens (farm L) were subsequently found in the broiler flocks, whereas other genotypes initially present in the broiler flocks turned up in cattle (farms A, D, and O). These results emphasize the importance of other farm animals on poultry farms for broiler flock colonization. Indications of persistent contamination of the broiler house were evident on four farms (C, D, I, and L) where matching genotypes were detected in consecutive broiler flocks, but not concurrently in other samples. By fla-RFLP, PFGE, and confirmed by AFLP, some genotypes proofed to be identical across different farms.

  17. Synthesized Population Databases: A Geospatial Database of US Poultry Farms

    PubMed Central

    Bruhn, Mark C.; Munoz, Breda; Cajka, James; Smith, Gary; Curry, Ross J.; Wagener, Diane K.; Wheaton, William D.

    2013-01-01

    The pervasive and potentially severe economic, social, and public health consequences of infectious disease in farmed animals require that plans be in place for a rapid response. Increasingly, agent-based models are being used to analyze the spread of animal-borne infectious disease outbreaks and derive policy alternatives to control future outbreaks. Although the locations, types, and sizes of animal farms are essential model inputs, no public domain nationwide geospatial database of actual farm locations and characteristics currently exists in the United States. This report describes a novel method to develop a synthetic dataset that replicates the spatial distribution of poultry farms, as well as the type and number of birds raised on them. It combines county-aggregated poultry farm counts, land use/land cover, transportation, business, and topographic data to generate locations in the conterminous United States where poultry farms are likely to be found. Simulation approaches used to evaluate the accuracy of this method when compared to that of a random placement alternative found this method to be superior. The results suggest the viability of adapting this method to simulate other livestock farms of interest to infectious disease researchers. PMID:25364787

  18. Understanding the role of farm dams in the Murray-Darling Basin in Australia through hydrological analysis coupled with stakeholder interviews

    NASA Astrophysics Data System (ADS)

    Kuil, Linda; Winnubst, Madelinde; van Dijk, Albert

    2013-04-01

    Climate predictions suggest that surface water availability in the Murray-Darling Basin (MDB) in Australia is more likely to decline than to increase in the next decades. In 2000, farm dams were first recognized as a significant risk to future flows in the MDB and have since been the subject of hydrological research. This study was conducted to provide insight into the role of farm dams in the Yass catchment, which is a subcatchment of the MDB close to Canberra, in order to indentify obstacles for integrated water management. The role of farm dams was investigated from both a hydrological and social perspective. Model prediction and data inference were used to estimate the impact of farm dams on streamflow. The density of farm dams in the catchment was estimated at 5.7 dams km-2. The impact on the Yass River was simulated to be in the order of 20 percent of mean annual streamflow. To understand why farm dams are used, semi-structured interviews were conducted to capture views and opinions of land holders. Research found that farm dams play a very important role in terms of individuals' water supply, although other systems are also used. Furthermore, land holders are responsible for their own water supply for drinking and agricultural water needs. Water rights are based on a right to rainfall or groundwater that is present on an individual's property. This means that landholders have both a need and a right to collect and store runoff. Current legislation put in place by the New South Wales government to restrict the amount of rain water to be captured does not seem to affect most people. If additional policy to minimize the impact of farm dams on streamflow were to be introduced, this has to be based on well-thought-out arguments based on a long term vision as the interview results indicate that farm dams are deeply embedded in Australian rural culture.

  19. Optimization of wind farm performance using low-order models

    NASA Astrophysics Data System (ADS)

    Dabiri, John; Brownstein, Ian

    2015-11-01

    A low order model that captures the dominant flow behaviors in a vertical-axis wind turbine (VAWT) array is used to maximize the power output of wind farms utilizing VAWTs. The leaky Rankine body model (LRB) was shown by Araya et al. (JRSE 2014) to predict the ranking of individual turbine performances in an array to within measurement uncertainty as compared to field data collected from full-scale VAWTs. Further, this model is able to predict array performance with significantly less computational expense than higher fidelity numerical simulations of the flow, making it ideal for use in optimization of wind farm performance. This presentation will explore the ability of the LRB model to rank the relative power output of different wind turbine array configurations as well as the ranking of individual array performance over a variety of wind directions, using various complex configurations tested in the field and simpler configurations tested in a wind tunnel. Results will be presented in which the model is used to determine array fitness in an evolutionary algorithm seeking to find optimal array configurations given a number of turbines, area of available land, and site wind direction profile. Comparison with field measurements will be presented.

  20. Farm Business Management, Volume II. Vocational Agricultural Education.

    ERIC Educational Resources Information Center

    Steward, Jim

    Designed to provide an advanced core of instruction in teaching farm business management, this curriculum guide for year 2 is intended for use as an adult program of instruction for a three-year period together with Farm Business Management I and III. (Volume I is available separately. See note.) The ten instructional units are presented in a…

  1. Evaluation of the Farm Training Program in Wisconsin. Final Report.

    ERIC Educational Resources Information Center

    Fox Valley Vocational, Technical, and Adult Education District, Appleton, WI.

    The final report presents the findings of an evaluation project set up to obtain reactions to the farm training program in Wisconsin from trainees and instructors. Two hundred and fifty farmers were selected for personal interviews on their respective farms. Each interview session lasted approximately 50 minutes. Data were obtained from the…

  2. Farm Business Management, Volume II. Vocational Agricultural Education.

    ERIC Educational Resources Information Center

    Steward, Jim

    Designed to provide an advanced core of instruction in teaching farm business management, this curriculum guide for year 2 is intended for use as an adult program of instruction for a three-year period together with Farm Business Management I and III. (Volume I is available separately. See note.) The ten instructional units are presented in a…

  3. The Changing Face of Farm Employment.

    ERIC Educational Resources Information Center

    Ilg, Randy E.

    1995-01-01

    Increased farm size, improved technology, and competing demands for farm land resulted in substantial decline in farm acreage and consequent declines in farm employment. Remaining farm operators are more likely to be white, highly educated, and have larger, capital-intensive farms. (SK)

  4. The profitability of automatic milking on Dutch dairy farms.

    PubMed

    Bijl, R; Kooistra, S R; Hogeveen, H

    2007-01-01

    Several studies have reported on the profitability of automatic milking based on different simulation models, but a data-based study using actual farm data has been lacking. The objective of this study was to analyze the profitability of dairy farms having an automatic milking system (AMS) compared with farms using a conventional milking system (CMS) based on real accounting data. In total, 62 farms (31 using an AMS and 31 using a CMS) were analyzed for the year 2003 in a case control study. Differences between the years 2002 and 2003 also were analyzed by comparing a subgroup of 16 farms with an AMS and 16 farms with a CMS. Matching was based on the time of investment in a milking system (same year), the total milk production per year, and intensity of land use (kg/ha). Results from 2003 showed that the farms with an AMS used, on average, 29% less labor than farms with a CMS. In contrast, farms using a CMS grew faster (37,132 kg of milk quota and 5 dairy cows) than farms with an AMS (-3,756 kg milk quota and 0.5 dairy cows) between 2002 and 2003. Dairy farmers with a CMS had larger (euro7,899) revenues than those with an AMS. However, no difference in the margin on dairy production was detected, partly because of numerically greater (euro6,822) variable costs on CMS farms. Dairy farms were compared financially based on the amount of money that was available for rent, depreciation, interest, labor, and profit (RDILP). The CMS farms had more money (euro15,566) available for RDILP than the AMS farms. This difference was caused by larger fixed costs (excluding labor) for the AMS farms, larger contractor costs (euro6,422), and larger costs for gas, water, and electricity (euro1,549). Differences in costs for contractors and for gas, water, and electricity were statistically significant. When expressed per full-time employee, AMS farms had greater revenues, margins, and gross margins per full-time employee than did CMS farms. This resulted in a substantially greater

  5. Characteristics of honey bee and non-Apis bee (Hymenoptera) farms in Canada.

    PubMed

    Daly, Z; Melhim, A; Weersink, A

    2012-08-01

    Here, we present a farm-level, Canada-wide analysis of Canadian bee farms in 2006; this article is the first report to distinguish between honey bee (Apis mellifera L.) farms and non-Apis bee (Hymenoptera) farms. Farms are characterized according to bee species, bee stocks, and whether the farm makes 50% or more of gross sales from bee-related activities. Farm characteristics, including bee stocks, gross sales, capital investments, land base, specialization, location, and operator demographics, are reported for the different farm types and sizes. Non-Apis bee farms are revealed to be a nontrivial part of the Canadian bee industry: 21.2% of Canadian bee farms have non-Apis bees and 16.6% have exclusively non-Apis bees. Important differences between honey bee farms and non-Apis bee farms also are found. These differences include the more land-intensive nature of non-Apis bee farms and the finding that non-Apis bee farms have greater diversity in terms of their primary commodity, even at higher bee stock levels.

  6. Opportunities and constraints of presently used thermal manikins for thermo-physiological simulation of the human body.

    PubMed

    Psikuta, Agnes; Kuklane, Kalev; Bogdan, Anna; Havenith, George; Annaheim, Simon; Rossi, René M

    2016-03-01

    Combining the strengths of an advanced mathematical model of human physiology and a thermal manikin is a new paradigm for simulating thermal behaviour of humans. However, the forerunners of such adaptive manikins showed some substantial limitations. This project aimed to determine the opportunities and constraints of the existing thermal manikins when dynamically controlled by a mathematical model of human thermal physiology. Four thermal manikins were selected and evaluated for their heat flux measurement uncertainty including lateral heat flows between manikin body parts and the response of each sector to the frequent change of the set-point temperature typical when using a physiological model for control. In general, all evaluated manikins are suitable for coupling with a physiological model with some recommendations for further improvement of manikin dynamic performance. The proposed methodology is useful to improve the performance of the adaptive manikins and help to provide a reliable and versatile tool for the broad research and development domain of clothing, automotive and building engineering.

  7. A decision support tool for sustainable planning of urban water systems: presenting the Dynamic Urban Water Simulation Model.

    PubMed

    Willuweit, Lars; O'Sullivan, John J

    2013-12-15

    Population growth, urbanisation and climate change represent significant pressures on urban water resources, requiring water managers to consider a wider array of management options that account for economic, social and environmental factors. The Dynamic Urban Water Simulation Model (DUWSiM) developed in this study links urban water balance concepts with the land use dynamics model MOLAND and the climate model LARS-WG, providing a platform for long term planning of urban water supply and water demand by analysing the effects of urbanisation scenarios and climatic changes on the urban water cycle. Based on potential urbanisation scenarios and their effects on a city's water cycle, DUWSiM provides the functionality for assessing the feasibility of centralised and decentralised water supply and water demand management options based on forecasted water demand, stormwater and wastewater generation, whole life cost and energy and potential for water recycling. DUWSiM has been tested using data from Dublin, the capital of Ireland, and it has been shown that the model is able to satisfactorily predict water demand and stormwater runoff.

  8. Opportunities and constraints of presently used thermal manikins for thermo-physiological simulation of the human body

    NASA Astrophysics Data System (ADS)

    Psikuta, Agnes; Kuklane, Kalev; Bogdan, Anna; Havenith, George; Annaheim, Simon; Rossi, René M.

    2016-03-01

    Combining the strengths of an advanced mathematical model of human physiology and a thermal manikin is a new paradigm for simulating thermal behaviour of humans. However, the forerunners of such adaptive manikins showed some substantial limitations. This project aimed to determine the opportunities and constraints of the existing thermal manikins when dynamically controlled by a mathematical model of human thermal physiology. Four thermal manikins were selected and evaluated for their heat flux measurement uncertainty including lateral heat flows between manikin body parts and the response of each sector to the frequent change of the set-point temperature typical when using a physiological model for control. In general, all evaluated manikins are suitable for coupling with a physiological model with some recommendations for further improvement of manikin dynamic performance. The proposed methodology is useful to improve the performance of the adaptive manikins and help to provide a reliable and versatile tool for the broad research and development domain of clothing, automotive and building engineering.

  9. Intraseasonal Variability of the South Asian Summer Monsoon: Present-day Simulations with the Regional Atmospheric Model HIRHAM5

    NASA Astrophysics Data System (ADS)

    Hanf, F. S.; Rinke, A.; Dethloff, K.

    2014-12-01

    Since 1950, observations show a robust negative trend of the seasonal rainfall associated with the South Asian summer monsoon over India coinciding with a continuous decrease in surface solar radiation ("dimming") over South Asia due to an increase of local aerosol emissions. On the intraseasonal timescale the summer monsoon fluctuates between periods of enhanced and reduced rainfall. The frequency of occurrence of these active and breaks monsoon phases affects directly the seasonal monsoon rainfall. This study investigates the regional pattern and changes of the South Asian monsoon for the period 1979-2012 using the regional atmospheric model HIRHAM5 with a horizontal resolution of 0.25° forced at the lateral and lower boundaries with ERA-Interim reanalysis data. Despite the dry bias in the mean summer monsoon rainfall over the Indian landmass, the simulated temperature and atmospheric circulation patterns are in agreement with the ERA-Interim reanalysis indicating a realistic representation of important dynamical summer monsoon features. In addition, mechanisms which controls active and break phases within the summer monsoon season are analyzed using daily outgoing longwave radiation model data as an identification tool of monsoon breaks as proposed by Krishnan et al. (2000). Model results reveal an increasing trend of the cumulative monsoon break days of around 1.4 days per year during the last 30 years. The possible link between this increasing of cumulative monsoon break days and the observed decrease of seasonal South Asian monsoon rainfall will be the scope of further investigations.

  10. A New Farming Systems Development Initiative

    SciTech Connect

    Hanlon, Edward; Capece, John

    2010-01-10

    Hendry County Sustainable Bio-Fuels Center (HCSBC) is introduced and its main components are explained. These primarily include (1) farming systems, (2) sustainability analysis, (3) economic analysis and (4) educational components. Each of these components is discussed in further details, main researchers and their responsibility areas and introduced. The main focus of this presentation is a new farming concept. The proposed new farming concept is an alternative to the current "two sides of the ditch" model, in which on one side are yield-maximizing, input-intensive, commodity price-dependent farms, while on the other side are publicly-financed, nutrient-removing treatment areas and water reservoirs trying to mitigate the externalized costs of food production systems and other human-induced problems. The proposed approach is rental of the land back to agriculture corporations during the restoration transition period in order to increase water storage (allowing for greater water flow-through and/or water storage on farms), preventing issues such as nutrients removal, using flood-tolerant crops and reducing soil subsidence. Various pros and cons of the proposed agricultural eco-services are discussed - the advantages include flexibility for participating farmers to achieve environmental outcomes with reduced costs and using innovative incentives; the minuses include the fact that the potential markets are not developed yet or that existing regulations may prevent agricultural producers from selling their services.

  11. Computational model for simulation of sequences of helicity and angular momentum transfer in turbid tissue-like scattering medium (Conference Presentation)

    NASA Astrophysics Data System (ADS)

    Doronin, Alexander; Meglinski, Igor

    2017-02-01

    Current report considers development of a unified Monte Carlo (MC) -based computational model for simulation of propagation of Laguerre-Gaussian (LG) beams in turbid tissue-like scattering medium. With a primary goal to proof the concept of using complex light for tissue diagnosis we explore propagation of LG beams in comparison with Gaussian beams for both linear and circular polarization. MC simulations of radially and azimuthally polarized LG beams in turbid media have been performed, classic phenomena such as preservation of the orbital angular momentum, optical memory and helicity flip are observed, detailed comparison is presented and discussed.

  12. Carbon farming economics: What have we learned?

    PubMed

    Tang, Kai; Kragt, Marit E; Hailu, Atakelty; Ma, Chunbo

    2016-05-01

    This study reviewed 62 economic analyses published between 1995 and 2014 on the economic impacts of policies that incentivise agricultural greenhouse (GHG) mitigation. Typically, biophysical models are used to evaluate the changes in GHG mitigation that result from landholders changing their farm and land management practices. The estimated results of biophysical models are then integrated with economic models to simulate the costs of different policy scenarios to production systems. The cost estimates vary between $3 and $130/t CO2 equivalent in 2012 US dollars, depending on the mitigation strategies, spatial locations, and policy scenarios considered. Most studies assessed the consequences of a single, rather than multiple, mitigation strategies, and few considered the co-benefits of carbon farming. These omissions could challenge the reality and robustness of the studies' results. One of the biggest challenges facing agricultural economists is to assess the full extent of the trade-offs involved in carbon farming. We need to improve our biophysical knowledge about carbon farming co-benefits, predict the economic impacts of employing multiple strategies and policy incentives, and develop the associated integrated models, to estimate the full costs and benefits of agricultural GHG mitigation to farmers and the rest of society.

  13. FY 2011 Second Quarter: Demonstration of New Aerosol Measurement Verification Testbed for Present-Day Global Aerosol Simulations

    SciTech Connect

    Koch, D

    2011-03-20

    The regional-scale Weather Research and Forecasting (WRF) model is being used by a DOE Earth System Modeling (ESM) project titled “Improving the Characterization of Clouds, Aerosols and the Cryosphere in Climate Models” to evaluate the performance of atmospheric process modules that treat aerosols and aerosol radiative forcing in the Arctic. We are using a regional-scale modeling framework for three reasons: (1) It is easier to produce a useful comparison to observations with a high resolution model; (2) We can compare the behavior of the CAM parameterization suite with some of the more complex and computationally expensive parameterizations used in WRF; (3) we can explore the behavior of this parameterization suite at high resolution. Climate models like the Community Atmosphere Model version 5 (CAM5) being used within the Community Earth System Model (CESM) will not likely be run at mesoscale spatial resolutions (10–20 km) until 5–10 years from now. The performance of the current suite of physics modules in CAM5 at such resolutions is not known, and current computing resources do not permit high-resolution global simulations to be performed routinely. We are taking advantage of two tools recently developed under PNNL Laboratory Directed Research and Development (LDRD) projects for this activity. The first is the Aerosol Modeling Testbed (Fast et al., 2011b), a new computational framework designed to streamline the process of testing and evaluating aerosol process modules over a range of spatial and temporal scales. The second is the CAM5 suite of physics parameterizations that have been ported into WRF so that their performance and scale dependency can be quantified at mesoscale spatial resolutions (Gustafson et al., 2010; with more publications in preparation).

  14. The effects of cyclists present at rural intersections on speed behavior and workload of car drivers: a driving simulator study.

    PubMed

    Duivenvoorden, Kirsten; Hogema, Jeroen; Hagenzieker, Marjan; Wegman, Fred

    2015-01-01

    The objective was to gain insight into how the number of cyclists, the cyclist's approach direction, and the cyclist's action affect the speed and mental workload of drivers approaching rural intersections. In addition, the effects of a speed-reducing measure on the interaction between cyclists and motorized traffic were examined. An experiment was conducted in a moving-base driving simulator. Thirty participants completed 3 runs each in 3 conditions: a baseline, a plateau, and a chicane condition. Participants drove an 80 km/h rural distributor road with 8 intersections. Eight cyclist scenarios were developed varying in the number of cyclists and the direction from which they approached the participants' lane. The Peripheral Detection Task was used to measure workload objectively and continuously. A plateau ahead of the intersection resulted in drivers entering the bicycle crossing with lower driving speeds but did not result in less serious potential conflicts compared to intersections without the speed-reducing measure. With respect to the presence of cyclists, drivers approaching the intersection without cyclists reached a minimum speed at a greater distance from the bicycle crossing compared to approaching the intersection with multiple cyclists in the baseline condition. At intersections with plateaus, drivers drove slower when encountering multiple cyclists compared to no cyclists. At intersections without the speed-reducing measure, drivers drove slower, decelerated stronger, and decelerated at a shorter distance to the bicycle crossing when encountering a suddenly crossing cyclist compared to a yielding cyclist. Although drivers have the right of way at rural intersections, drivers' speed behavior was affected by the number and action of cyclists. From a road safety point of view, driving speeds at rural intersections need to be further reduced to limit the seriousness of potential conflicts between cyclists and motorized traffic.

  15. Effects of Turbine Spacing in Very Large Wind Farms

    NASA Astrophysics Data System (ADS)

    Andersen, Søren Juhl; Sørensen, Jens Nørkær; Mikkelsen, Robert Flemming

    2015-11-01

    The Dynamic Wake Meandering model(DWM) by Larsen et al. (2007) is considered state of the art for modelling the wake behind a wind turbine. DWM assumes a quasi-steady wake deficit transported as a passive tracer by large atmospheric scales. The approach is also applied to wake interaction within wind farms, although certain aspects of the complex wake interaction are not captured, see Churchfield et al. (2014). Recent studies have shown how turbines introduce low frequencies in the wake, which could describe some of the shortcomings. Chamorro et al. (2015) identified three regions of different lengths scales. Iungo et al. (2013) related low frequencies to the hub vortex instability. Okulov et al. (2014) found Strouhal numbers in the far wake stemming from the rotating helical vortex core. Simulations by Andersen et al. (2013) found low frequencies to be inherent in the flow inside an infinite wind farm. LES simulations of large wind farms are performed with full aero-elastic Actuator Lines. The simulations investigate the inherent dynamics inside wind farms in the absence of atmospheric turbulence compared to cases with atmospheric turbulence. Resulting low frequency structures are inherent in wind farms for certain turbine spacings and affect both power production and loads. Funded by Danish Council for Strategic Research (grant 2104-09-067216/DSF), the Nordic Consortium on Optimization and Control of Wind Farms, and EuroTech wind project. The proprietary data for Vestas' NM80 turbine has been used.

  16. Potential market of wind farm in China

    SciTech Connect

    Pengfei Shi

    1996-12-31

    Wind energy resources are abundant in China, in southeast coast area along with the rapid economic growth, electricity demand has been sharply increased, due to complex terrain detailed assessments are in urgent need. Advanced methodology and computer model should be developed. In this paper the existing wind farms, installed capacity, manufacturers share and projects in the near future are presented. For further development of wind farm in large scale, different ways of local manufacturing wind turbine generators (WTG) are going on. Current policy and barriers are analyzed. 4 refs., 2 figs., 4 tabs.

  17. Farm level risk factors for fluoroquinolone resistance in E. coli and thermophilic Campylobacter spp. on poultry farms.

    PubMed

    Taylor, N M; Wales, A D; Ridley, A M; Davies, R H

    2016-10-01

    Data on husbandry practices, performance, disease and drug use were collected during a cross-sectional survey of 89 poultry meat farms in England and Wales to provide information on possible risk factors for the occurrence of fluoroquinolone (FQ)-resistant bacteria. Faeces samples were used to classify farms as "affected" or "not affected" by FQ-resistant (FQr) Escherichia coli or Campylobacter spp. Risk factor analysis identified the use of FQ on the farms as having by far the strongest association, among the factors considered, with the occurrence of FQr bacteria. Resistant E. coli and/or Campylobacter spp. were found on 86% of the farms with a history of FQ use. However, a substantial proportion of farms with no history of FQ use also yielded FQr organisms, suggesting that resistant bacteria may transfer between farms. Further analysis suggested that for Campylobacter spp., on-farm hygiene, cleaning and disinfection between batches of birds and wildlife control were of most significance. By contrast, for E. coli biosecurity from external contamination was of particular importance, although the modelling indicated that other factors were likely to be involved. Detailed studies on a small number of sites showed that FQr E. coli can survive routine cleaning and disinfection. It appears difficult to avoid the occurrence of resistant bacteria when FQ are used on a farm, but the present findings provide evidence to support recommendations to reduce the substantial risk of the incidental acquisition of such resistance by farms where FQ are not used.

  18. Is experience on a farm an effective approach to understanding animal products and the management of dairy farming?

    PubMed

    Mochizuki, Mariko; Osada, Masahiro; Ishioka, Katsumi; Matsubara, Takako; Momota, Yutaka; Yumoto, Norio; Sako, Toshinori; Kamiya, Shinji; Yoshimura, Itaru

    2014-03-01

    The understanding of animal products and dairy farming is important for the promotion of dairy farming. Thus, to examine the effects of farm experience on the understanding of animal products and the management of dairy farming, the interaction between students and dairy cows was investigated in groups of first-year veterinary nursing students in 2011 and 2012 (n = 201). These students included 181 women and 20 men. Nine items about dairy cows were presented in a questionnaire. The survey was performed before and after praxis on the educational farm attached to the authors' university. After praxis on the farm, increases occurred in the number of positive responses to the items involving the price of milk, dairy farming and the taste of milk. For these items, a significant difference (P < 0.05) was found between the scores obtained before and after training. The results of the study suggested that farm experience is useful for improving the understanding of animal products and dairy farming.

  19. Computer Assisted Instruction for Training Farm Equipment Parts Personnel.

    ERIC Educational Resources Information Center

    Nechville, Jerry

    1979-01-01

    Describes the training program for farm equipment over-the-counter parts sales which makes use of a parts inventory control simulation supported by a computerized inventory system to develop entry-level competencies. Discusses advantages of the program, such as (1) it is a realistic simulation, and (2) students receive immediate feedback. (LRA)

  20. LES studies of wind farms including wide turbine spacings and comparisons with the CWBL engineering model

    NASA Astrophysics Data System (ADS)

    Stevens, Richard; Gayme, Dennice; Meyers, Johan; Meneveau, Charles

    2015-11-01

    We present results from large eddy simulations (LES) of wind farms consisting of tens to hundreds of turbines with respective streamwise and spanwise spacings approaching 35 and 12 turbine diameters. Even in staggered farms where the distance between consecutive turbines in the flow direction is more than 50 turbine diameters, we observe visible wake effects. In aligned farms, the performance of the turbines in the fully developed regime, where the power output as function of the downstream position becomes constant, is shown to primarily depend on the streamwise distance between consecutive turbine rows. However, for other layouts the power production in the fully developed regime mainly depends on the geometrical mean turbine spacing (inverse turbine density). These findings agree very well with predictions from our recently developed coupled wake boundary layer (CWBL) model, which introduces a two way coupling between the wake (Jensen) and top-down model approaches (Stevens et al. JRSE 7, 023115, 2015). To further validate the CWBL model we apply it to the problem of determining the optimal wind turbine thrust coefficient for power maximization over the entire farm. The CWBL model predictions agree very well with recent LES results (Goit & Meyers, JFM 768, 5-50, 2015). FOM Fellowships for Young Energy Scientists (YES!), NSF (IIA 1243482, the WINDINSPIRE project), ERC (FP7-Ideas, 306471).

  1. Numerical Simulations of the Evolution of the CO2 Atmosphere of Mars: 4.53 Ga to the Present

    NASA Technical Reports Server (NTRS)

    Manning, C. V.; McKay, C. P.; Zahnle, K. J.

    2003-01-01

    In this paper we approach four key questions that are central to our understanding of the nature of climate change on Mars: 1. By what mechanism has the evolution of the CO2 atmosphere, dominated at early times by violent process, been guided to the moderate quantities present today? 2.How do obliquity cycles affect the migration of CO2 between the various reservoirs of CO2, and what effect does this have on the bulk atmosphere of the planet in time? 3. Is the geophysical evidence that the last few Myr experienced periods that are substantially wetter than the present attributable to a substantially more massive greenhouse atmosphere? 4. Is the current atmospheric pressure determined primarily by the partial pressure of CO2 in cold (approx. 148 K) ice caps, or is it because disequilibrium water, and hence weathering, ceases at pressures below the triple point of water?

  2. Numerical Simulations of the Evolution of the CO2 Atmosphere of Mars: 4.53 Ga to the Present

    NASA Technical Reports Server (NTRS)

    Manning, C. V.; McKay, C. P.; Zahnle, K. J.

    2003-01-01

    In this paper we approach four key questions that are central to our understanding of the nature of climate change on Mars: 1. By what mechanism has the evolution of the CO2 atmosphere, dominated at early times by violent process, been guided to the moderate quantities present today? 2.How do obliquity cycles affect the migration of CO2 between the various reservoirs of CO2, and what effect does this have on the bulk atmosphere of the planet in time? 3. Is the geophysical evidence that the last few Myr experienced periods that are substantially wetter than the present attributable to a substantially more massive greenhouse atmosphere? 4. Is the current atmospheric pressure determined primarily by the partial pressure of CO2 in cold (approx. 148 K) ice caps, or is it because disequilibrium water, and hence weathering, ceases at pressures below the triple point of water?

  3. 29 CFR 780.142 - Practices on a farm not related to farming operations.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 29 Labor 3 2010-07-01 2010-07-01 false Practices on a farm not related to farming operations. 780... FAIR LABOR STANDARDS ACT General Scope of Agriculture âsuch Farming Operationsâ-on the Farm § 780.142 Practices on a farm not related to farming operations. Practices performed on a farm in connection...

  4. Transient climate simulations of the deglaciation 21-9 thousand years before present; PMIP4 Core experiment design and boundary conditions

    NASA Astrophysics Data System (ADS)

    Ivanovic, Ruza; Gregoire, Lauren; Kageyama, Masa; Roche, Didier; Valdes, Paul; Burke, Andrea; Drummond, Rosemarie; Peltier, W. Richard; Tarasov, Lev

    2016-04-01

    The last deglaciation, which marked the transition between the last glacial and present interglacial periods, was punctuated by a series of rapid (centennial and decadal) climate changes. Numerical climate models are useful for investigating mechanisms that underpin the events, especially now that some of the complex models can be run for multiple millennia. We have set up a Paleoclimate Modelling Intercomparison Project (PMIP) working group to coordinate efforts to run transient simulations of the last deglaciation, and to facilitate the dissemination of expertise between modellers and those engaged with reconstructing the climate of the last 21 thousand years. Here, we present the design of a coordinated Core simulation over the period 21-9 thousand years before present (ka) with time varying orbital forcing, greenhouse gases, ice sheets, and other geographical changes. A choice of two ice sheet reconstructions is given. Additional focussed simulations will also be coordinated on an ad-hoc basis by the working group, for example to investigate the effect of ice sheet and iceberg meltwater, and the uncertainty in other forcings. Some of these focussed simulations will concentrate on shorter durations around specific events to allow the more computationally expensive models to take part. Ivanovic, R. F., Gregoire, L. J., Kageyama, M., Roche, D. M., Valdes, P. J., Burke, A., Drummond, R., Peltier, W. R., and Tarasov, L.: Transient climate simulations of the deglaciation 21-9 thousand years before present; PMIP4 Core experiment design and boundary conditions, Geosci. Model Dev. Discuss., 8, 9045-9102, doi:10.5194/gmdd-8-9045-2015, 2015.

  5. On-farm safety program.

    PubMed

    Carrabba, James J; Scofield, Sharon; May, John

    2008-01-01

    Rates of fatal occupational injuries in New York agriculture far outstrip the average for all American workers. Among its various approaches to this problem, the New York Center for Agricultural Medicine and Health (NYCAMH) sponsored an On-Farm Safety Program that sought to reduce farm worksite hazards and to enhance understanding of safe farm practices through a two-step process. First, an on-farm hazard survey identified hazards that may lead to farm injury and suggested improvements to correct those hazards. Second, on-farm safety training sessions were offered to increase safety knowledge and influence adoption of safe work practices. Over a 2-year period, 124 farms were surveyed and 187 safety training sessions were conducted on a total of 271 New York farms. Follow-up phone surveys were conducted with 97 (78%) of the on-farm survey sites at roughly 6 months. Of the 97 survey farms that completed the telephone survey, 77 (79%) reported having made safety improvements. Hazards resolved tended to be less labor intensive and expensive than some of the other hazards observed. Ninety-six (99%) of the farms that completed the telephone follow-up survey found the on-farm visits useful and said that NYCAMH should continue to offer the On-Farm Safety Program. No data were collected to assess the impact of these efforts upon occupational injury and illness. This appears to be an effective means of outreach to heighten safety awareness of the farm population and to address some of the observed worksite hazards. It is unclear whether this approach substantially impacts the elevated risk of injury in agriculture.

  6. Farm work practices and farm injuries in Colorado

    PubMed Central

    Stallones, L; Beseler, C

    2003-01-01

    Study objectives: To describe the farm work patterns and the relationship between hours spent working on specific farm tasks and task specific work related injuries among women and men. Design: A cross sectional survey of farm operators and their spouses in an eight county area of Colorado was conducted. Personal interviews were conducted between 1993 and 1997. Interviews took between 45 minutes to two hours to complete, depending on the complexity of individuals' personal histories. Farms were selected using stratified random sampling technique. Setting: Eight counties in Northeastern Colorado representing 47% of agricultural production in the state. Participants: A total of 301 women and 459 men who were farm residents and involved in farm work were recruited. Outcome measure: Self reported injuries resulting in medical attention or treatment other than first aid, or inability to do normal work activities, or loss of consciousness, or transfer to another job were assessed in relationship to the specific job task being performed at the time of the injury. Results: Women were at higher risk for injury than men when involved with other farm chores (rate ratio 8.18). For all other task related injuries, men and women were at similar risk when compared using hours of exposure to the farm tasks. Conclusion: Farm safety training and injury prevention programs need to include women working on farms. PMID:12966013

  7. Farm Work-Related Asthma Among US Primary Farm Operators

    PubMed Central

    Mazurek, Jacek M.; White, Gretchen E.; Rodman, Chad; Schleiff, Patricia L.

    2015-01-01

    The objective of this study was to estimate the prevalence of current asthma and the proportion of current asthma that is related to work on the farm among primary farm operators. The 2011 Farm and Ranch Safety Survey data were used to produce estimates and prevalence odds ratios. An estimated 5.1% of farm operators had asthma. Of these, 15.4% had farm work-related asthma. Among operators with farm work-related asthma, 54.8% (95% confidence interval [CI]: 41.8%–68.2%) had an asthma attack in the prior 12 months and 33.3% (95% CI: 21.2%–45.4%) had an asthma attack that occurred while doing farm work. Of those who had an asthma attack that occurred while doing farm work, 65.0% associated their asthma attack with plant/tree materials. This study provides updated information on asthma and the proportion of current asthma that is related to work on the farm and identifies certain groups of farm operators that might benefit from workplace asthma prevention intervention. PMID:25635741

  8. Transgenic Farm Animals

    NASA Astrophysics Data System (ADS)

    Solomon, Morse B.; Eastridge, Janet S.; Paroczay, Ernest W.

    Conventional science to improve muscle and meat parameters has involved breeding strategies, such as selection of dominant traits or selection of preferred traits by cross breeding, and the use of endogenous and exogenous hormones. Improvements in the quality of food products that enter the market have largely been the result of postharvest intervention strategies. Biotechnology is a more extreme scientific method that offers the potential to improve the quality, yield, and safety of food products by direct genetic manipulation. In the December 13, 2007 issue of the Southeast Farm Press, an article by Roy Roberson pointed out that biotechnology is driving most segments of U.S. farm growth. He indicated that nationwide, the agriculture industry is booming and much of that growth is the result of biotechnology advancements.

  9. Consumer beliefs regarding farmed versus wild fish.

    PubMed

    Claret, Anna; Guerrero, Luis; Ginés, Rafael; Grau, Amàlia; Hernández, M Dolores; Aguirre, Enaitz; Peleteiro, José Benito; Fernández-Pato, Carlos; Rodríguez-Rodríguez, Carmen

    2014-08-01

    Aquaculture is a food-producing activity, alternative to traditional extractive fishing, which still acts as a reference for most consumers. The main objective of the present paper was to study which consumer beliefs, regarding farmed versus wild fish, hinder the potential development of the aquaculture sector. To achieve this purpose the study was organized into two complementary steps: a qualitative approach (focus groups) aimed at assessing consumer perception about wild and farmed fish and to identify the salient beliefs that differentiate them; and a quantitative approach (survey by means of a questionnaire) to validate the results obtained in the focus group discussions over a representative sample of participants (n = 919). Results showed that participants perceive clear differences between farmed and wild fish. Although no significant differences between both kinds of fish were detected on safety, in general farmed fish was perceived to be less affected by marine pollution, heavy metals and parasites. In the contrary, wild fish was considered to have healthier feeding, to contain fewer antibiotics and to be fresher, healthier, less handled and more natural. Beliefs related to quality were in favour of wild fish, while those related to availability and price were in favour of farmed fish. Significant differences were observed in the perception of both kinds of fish depending on the consumers' objective knowledge about fish, on the level of education, age and gender and on the three segments of consumers identified: "Traditional/Conservative", "Connoisseur", "Open to aquaculture". The results provided could play an important role when planning and designing efficient marketing strategies for promoting farmed fish by adapting the information provided to the perception of each segment of consumers identified by the present study. Copyright © 2014 Elsevier Ltd. All rights reserved.

  10. AGRICULTURAL OCCUPATIONS OTHER THAN FARMING IN MISSOURI.

    ERIC Educational Resources Information Center

    GRIFFITH, WARREN L.

    THE OBJECTIVES OF THIS STUDY WERE TO--(1) IDENTIFY PRESENT AND EMERGING OFF-FARM AGRICULTURAL OCCUPATIONS, (2) DETERMINE EMPLOYMENT TRENDS, (3) RELATE TYPES OF OCCUPATIONS TO STATE REGIONS, (4) DETERMINE CHARACTERISTICS OF THESE OCCUPATIONS, AND (5) DETERMINE CHARACTERISTICS OF AGRICULTURAL BUSINESSES. A SURVEY OF 3,315 FIRMS IN RURAL AREAS OF THE…

  11. CALIFORNIA, ANNUAL FARM LABOR REPORT, 1961.

    ERIC Educational Resources Information Center

    LENHART, MARGOT W.

    STATISTICAL TRENDS AND GOVERNMENT PROGRAMS IN DIFFERENT AREAS TO AID DIFFERENT TYPES OF FARMERS WERE PRESENTED. BETWEEN 1960 AND 1961, CALIFORNIA'S OVERALL CROP PRODUCTION ROSE BY ALMOST ONE PERCENT, WHILE TOTAL ACREAGE HARVESTED AND VALUE OF PRODUCTION DECLINED SLIGHTLY. FARMING UNDERWENT SIGNIFICANT CHANGES IN MANY COMMUNITIES. MORE MACHINES AND…

  12. CALIFORNIA, ANNUAL FARM LABOR REPORT, 1961.

    ERIC Educational Resources Information Center

    LENHART, MARGOT W.

    STATISTICAL TRENDS AND GOVERNMENT PROGRAMS IN DIFFERENT AREAS TO AID DIFFERENT TYPES OF FARMERS WERE PRESENTED. BETWEEN 1960 AND 1961, CALIFORNIA'S OVERALL CROP PRODUCTION ROSE BY ALMOST ONE PERCENT, WHILE TOTAL ACREAGE HARVESTED AND VALUE OF PRODUCTION DECLINED SLIGHTLY. FARMING UNDERWENT SIGNIFICANT CHANGES IN MANY COMMUNITIES. MORE MACHINES AND…

  13. Quantitative Study of the Present-Day Climate of the Middle Tennessee Elk Watershed Area From Global and Regional Climate Model Simulations

    NASA Astrophysics Data System (ADS)

    Kebede, G.

    2015-12-01

    As part of a wider hydro climatic modeling research, we studied the spatial and temporal variability of precipitation and temperature over the Middle Tennessee Elk watershed and its environs using regional climate model simulations over the past 30 years. Three sets of simulations with the Hadley Center's regional climate model (PRECIS) were carried out for the present day climate (1980-2010) at a resolution of 25km covering the southeastern U.S. These three sets simulations are driven by lateral boundary conditions taken from ERA-Interim reanalysis, and two global climate models (HadCM3 and ECHAM5) respectively. For validation, high resolution observed daily data sets from North American Land-Data Assimilation System (NLDAS) and Climate Research Unit, CRU data are used. Preliminary results show that the spatial distribution of the present-day seasonal mean rainfall and temperature, simulated by PRECIS, are not only consistent with NLDAS and CRU but also captured fine scale spatial structures that are missing in the global model simulations due to their coarse resolution. In addition, the annual cycle and intera-anual variability, particularly that of temperature, are reasonably well reproduced by the PRECIS. When comparing the PRECIS simulations with the driving GCMs, PRECIS is sensitive to the choice of the driving GCM, suggesting a careful selection of driving GCM based on the current climate performance for the use of future climate impact assessment. Quantitative understanding of the climate system and better estimation of the fresh water balance over the Middle Tennessee Elk watershed is a vital corner stone for a sustainable economic growth of the region over the coming decades.

  14. Adaptation and development of software simulation methodologies for cardiovascular engineering: present and future challenges from an end-user perspective.

    PubMed

    Díaz-Zuccarini, V; Narracott, A J; Burriesci, G; Zervides, C; Rafiroiu, D; Jones, D; Hose, D R; Lawford, P V

    2009-07-13

    This paper describes the use of diverse software tools in cardiovascular applications. These tools were primarily developed in the field of engineering and the applications presented push the boundaries of the software to address events related to venous and arterial valve closure, exploration of dynamic boundary conditions or the inclusion of multi-scale boundary conditions from protein to organ levels. The future of cardiovascular research and the challenges that modellers and clinicians face from validation to clinical uptake are discussed from an end-user perspective.

  15. Adaptation and development of software simulation methodologies for cardiovascular engineering: present and future challenges from an end-user perspective

    PubMed Central

    Díaz-Zuccarini, V.; Narracott, A.J.; Burriesci, G.; Zervides, C.; Rafiroiu, D.; Jones, D.; Hose, D.R.; Lawford, P.V.

    2009-01-01

    This paper describes the use of diverse software tools in cardiovascular applications. These tools were primarily developed in the field of engineering and the applications presented push the boundaries of the software to address events related to venous and arterial valve closure, exploration of dynamic boundary conditions or the inclusion of multi-scale boundary conditions from protein to organ levels. The future of cardiovascular research and the challenges that modellers and clinicians face from validation to clinical uptake are discussed from an end-user perspective. PMID:19487202

  16. Why the Coriolis force turns a wind farm wake to the right in the Northern Hemisphere

    NASA Astrophysics Data System (ADS)

    van der Laan, M. P.; Sørensen, N. N.

    2016-09-01

    The interaction between the Coriolis force and a wind farm wake is investigated by Reynolds-Averaged Navier-Stokes simulations, using two different wind farm representations: a high roughness and 5×5 actuator disks. Surprisingly, the calculated wind farm wake deflection is opposite in the two simulations. A momentum balance in the cross flow direction shows that the interaction between the Coriolis force and the 5 × 5 actuator disks is complex due to turbulent mixing of fresh momentum from above into the wind farm, which is not observed for the interaction between the Coriolis force and a roughness change.

  17. Wind farm electrical system

    DOEpatents

    Erdman, William L.; Lettenmaier, Terry M.

    2006-07-04

    An approach to wind farm design using variable speed wind turbines with low pulse number electrical output. The output of multiple wind turbines are aggregated to create a high pulse number electrical output at a point of common coupling with a utility grid network. Power quality at each individual wind turbine falls short of utility standards, but the aggregated output at the point of common coupling is within acceptable tolerances for utility power quality. The approach for aggregating low pulse number electrical output from multiple wind turbines relies upon a pad mounted transformer at each wind turbine that performs phase multiplication on the output of each wind turbine. Phase multiplication converts a modified square wave from the wind turbine into a 6 pulse output. Phase shifting of the 6 pulse output from each wind turbine allows the aggregated output of multiple wind turbines to be a 24 pulse approximation of a sine wave. Additional filtering and VAR control is embedded within the wind farm to take advantage of the wind farm's electrical impedence characteristics to further enhance power quality at the point of common coupling.

  18. Transient simulations of the present and the last interglacial climate using the Community Climate System Model version 3: effects of orbital acceleration

    NASA Astrophysics Data System (ADS)

    Varma, Vidya; Prange, Matthias; Schulz, Michael

    2016-11-01

    Numerical simulations provide a considerable aid in studying past climates. Out of the various approaches taken in designing numerical climate experiments, transient simulations have been found to be the most optimal when it comes to comparison with proxy data. However, multi-millennial or longer simulations using fully coupled general circulation models are computationally very expensive such that acceleration techniques are frequently applied. In this study, we compare the results from transient simulations of the present and the last interglacial with and without acceleration of the orbital forcing, using the comprehensive coupled climate model CCSM3 (Community Climate System Model version 3). Our study shows that in low-latitude regions, the simulation of long-term variations in interglacial surface climate is not significantly affected by the use of the acceleration technique (with an acceleration factor of 10) and hence, large-scale model-data comparison of surface variables is not hampered. However, in high-latitude regions where the surface climate has a direct connection to the deep ocean, e.g. in the Southern Ocean or the Nordic Seas, acceleration-induced biases in sea-surface temperature evolution may occur with potential influence on the dynamics of the overlying atmosphere.

  19. Employment Opportunities and Competencies Needed in Farm Occupations in Selected Counties in Kentucky.

    ERIC Educational Resources Information Center

    Neel, C.O., Jr.

    To identify present and emerging farm occupations and necessary competencies, personal interviews were conducted by teachers of agriculture with a random sample of 329 farm operators in 11 selected counties in Kentucky. Slightly more than 75 percent of the operators interviewed were owners living on a farm. Some population characteristics were:…

  20. Development of a farm-firm modelling system for evaluation of herbaceous energy crops

    SciTech Connect

    English, B.C.; Alexander, R.R.; Loewen, K.H.; Coady, S.A.; Cole, G.V.; Goodman, W.R. . Dept. of Agricultural Economics and Rural Sociology)

    1992-01-01

    A complete analysis is performed to simulate biomass production incorporated into a realistic whole farm situation, including or replacing a typical crop mix. Representative farms are constructed to accommodate such simulation. Four management systems are simulated for each firm, with each simulation depicting a different crop mix and/or use of different farming technologies and production methods. The first simulation was a base farm plan in which the operator would maintain the historical crop mix for the area, participate in all price support programs, and not participate in either a conservative reserve or a biomass production program. In the second simulation, the operator would again maintain the historical crop mix, would not participate in a conservation reserve or biomass production program, and would be ineligible to participate in any price support system. The third simulation introduced the Conservation Reserve Program (CRP) and included participation in all price support programs. The fourth simulation introduced a biomass crop production enterprise (switchgrass) as an alternative to enrolling highly erodible cropland in the CRP and allowed participation in price support programs. Simulations were made for three farms, two in West Tennessee and on in South Georgia. Results indicate that erosion is likely to be reduced more by the diversion of cropland to permanent vegetative cover on farms similar to the more highly erodible West Tennessee farms than on the less erodible Tift County, Georgia farm. Equivalent reductions in erosion rates result from entering highly erodible cropland in the CRP and from production of switchgrass as a biomass energy crop. Both switchgrass and CRP farm plans result in decreased net returns from the base plan, although the biomass farm plans are, in general, more profitable than the CRP plans.

  1. Conceptual design report for tank farm restoration and safe operations, project W-314

    SciTech Connect

    Briggs, S.R., Westinghouse Hanford

    1996-05-02

    This Conceptual Design Report (CDR) presents the conceptual level design approach that satisfies the established technical requirements for Project W-314, `Tank Farm Restoration and Safe Operations.` The CDR also addresses the initial cost and schedule baselines for performing the proposed Tank Farm infrastructure upgrades. The scope of this project includes capital improvements to Hanford`s existing tank farm facilities(primarily focused on Double- Shell Tank Farms) in the areas of instrumentation/control, tank ventilation, waste transfer, and electrical systems.

  2. [Veterinary medicine and organic animal husbandry. III. Animal health in organic dairy farms].

    PubMed

    van Klink, E G; de Ruyter, W G; Sijpkens, C D; van Ham, P W

    1995-03-01

    Animal health is dealt with differently on biological farms then on conventional farms. On biological farms, stockmen see their animals not only as individual animals, but also as part of a herd in a balanced ecosystem. Disease prevention is therefore given much thought. The use of medicines is selective and subjected to strict regulations. This paper presents a summary of disease incidence in dairy cattle on biological farms and highlights specific problems and problem prevention in biological animal husbandry.

  3. Long Term Manipulations of Intact Microbial Mat Communities in a Greenhouse Collaboratory: Simulating Earth's Present and Past Field Environments

    NASA Technical Reports Server (NTRS)

    Bebout, Brad; DesMarais, David J.; Discipulo, Mykell; Embaye, Tsegereda; Garcia-Pichel, Ferran; Hogan, Mary; Jahnke, Linda L.; Keller, Richard M.; Miller, Scott R.; Prufert-Bebout, Leslie E.; hide

    2002-01-01

    Photosynthetic microbial mat communities were obtained from marine hypersaline saltern ponds, maintained in a greenhouse facility, and examined for the effects of salinity variations. Because these microbial mats are considered to be useful analogs of equivalent ancient marine communities, they offer insights about evolutionary events during the greater than 3 billion year time interval wherein mats co-evolved with Earth's geosphere and atmosphere. Although photosynthetic mats can be highly dynamic and exhibit extremely high activity, the mats in the present study have been maintained for more than one year with relatively minor changes. The major groups of microorganisms, as assayed using microscopic, genetic, and biomarker methodologies, are essentially the same as those in the original field samples. Field and greenhouse mats were similar with respect to rates of exchange of oxygen and dissolved inorganic carbon across the mat-water interface, both during the day and at night. Field and greenhouse mats exhibited similar rates of efflux of methane and hydrogen. Manipulations of salinity in the water overlying the mats produced changes in the community that strongly resemble those observed in the field. A collaboratory testbed and an array of automated features are being developed to support remote scientific experimentation with the assistance of intelligent software agents. This facility will permit teams of investigators to explore ancient environmental conditions that are rare or absent today but might have influenced the early evolution of these photosynthetic ecosystems.

  4. Long-term manipulations of intact microbial mat communities in a greenhouse collaboratory: simulating earth's present and past field environments.

    PubMed

    Bebout, Brad M; Carpenter, Steven P; Des Marais, David J; Discipulo, Mykell; Embaye, Tsegereda; Garcia-Pichel, Ferran; Hoehler, Tori M; Hogan, Mary; Jahnke, Linda L; Keller, Richard M; Miller, Scott R; Prufert-Bebout, Leslie E; Raleigh, Chris; Rothrock, Michael; Turk, Kendra

    2002-01-01

    Photosynthetic microbial mat communities were obtained from marine hypersaline saltern ponds, maintained in a greenhouse facility, and examined for the effects of salinity variations. Because these microbial mats are considered to be useful analogs of ancient marine communities, they offer insights about evolutionary events during the >3 billion year time interval wherein mats co-evolved with Earth's lithosphere and atmosphere. Although photosynthetic mats can be highly dynamic and exhibit extremely high activity, the mats in the present study have been maintained for >1 year with relatively minor changes. The major groups of microorganisms, as assayed using microscopic, genetic, and biomarker methodologies, are essentially the same as those in the original field samples. Field and greenhouse mats were similar with respect to rates of exchange of oxygen and dissolved inorganic carbon across the mat-water interface, both during the day and at night. Field and greenhouse mats exhibited similar rates of efflux of methane and hydrogen. Manipulations of salinity in the water overlying the mats produced changes in the community that strongly resemble those observed in the field. A collaboratory testbed and an array of automated features are being developed to support remote scientific experimentation with the assistance of intelligent software agents. This facility will permit teams of investigators the opportunity to explore ancient environmental conditions that are rare or absent today but that might have influenced the early evolution of these photosynthetic ecosystems.

  5. The Atmospheric Moisture Budget over the Great Lakes: Comparing Reanalysis and CMIP5 Present-day Simulations

    NASA Astrophysics Data System (ADS)

    Steiner, A. L.; Gates, O.; Posselt, D. J.

    2016-12-01

    The Laurentian Great Lakes are crucial for the region's economy, recreation and water supply, yet the prediction of precipitation and its impact on the region's water balance is still poorly constrained. Here we use a suite of reanalysis products and CMIP5 global models to understand the factors that drive present-day precipitation in the region. We focus the key components of the atmospheric water balance - precipitation, evaporation and moisture flux divergence - to understand the dominant drivers of interannual variability of precipitation in the region and explain regional biases and their causes. We compare four different reanalysis products (ERA-Interim, NCEP CSFR, NASA MERRA and the NARR) with a subset of global AOGCMs to understand the role of the moisture budget on regional precipitation variability. Precipitation differences between three of the reanalysis products and observations range from 20-50%, with a shift towards earlier spring precipitation than observed. The NCEP CSFR product showing a bi-modal precipitation cycle with maxima in April and November, distinctly different from the unimodal annual cycle in the observations and other reanalysis products. Interestingly, this pattern is produced in several of the CMIP5 models as well. We evaluate the driver of this early spring bias in precipitation over the region by examining the moisture budget components, including local evapotranspiration and large-scale dynamics.

  6. Farm Safety Practices and Farm Size in New South Wales.

    PubMed

    Bailey, Jannine; Dutton, Tegan; Payne, Kristy; Wilson, Ross; Brew, Bronwyn K

    2017-01-01

    There is some evidence to suggest that safety on small-area farms may not be high priority due to economic constraints and lack of knowledge. This has important ramifications for injury and economic burden. The objective of this research was to conduct a pilot study to investigate whether small- to medium-area farms implement fewer safety practices than large-area farms. Farmers were recruited from farm safety training days, field days, and produce stores in rural New South Wales (NSW), Australia. Small- and medium-area farms less than 500 ha (1235 acres) in size were aggregated for analysis and compared with large-area farms (≥500 ha) for survey items, including safety equipment owned and used, safety practices protecting children, barriers to improving safety, and causes of injury. Overall, small/medium-area farms were found to own less safety equipment and to employ less safety practices than large-area farms. In particular, fewer tractors were fitted with rollover protection structures, there was less signage, less hearing protection, and fewer machinery guides. Injury rates were slightly less for small/medium-area farms, particularly involving vehicles. Small- and medium-area farmers were more likely to report lack of skills as barriers to making safety improvements. This pilot study found some evidence that small/medium-area farms implement fewer safety practices than large-area farms. A larger study is warranted to investigate this further, with particular focus on barriers and ways to overcome them. This could have important ramifications for government policies supporting struggling farmers on small/medium-area farms.

  7. Wind farm density and harvested power in very large wind farms: A low-order model

    NASA Astrophysics Data System (ADS)

    Cortina, G.; Sharma, V.; Calaf, M.

    2017-07-01

    In this work we create new understanding of wind turbine wakes recovery process as a function of wind farm density using large-eddy simulations of an atmospheric boundary layer diurnal cycle. Simulations are forced with a constant geostrophic wind and a time varying surface temperature extracted from a selected period of the Cooperative Atmospheric Surface Exchange Study field experiment. Wind turbines are represented using the actuator disk model with rotation and yaw alignment. A control volume analysis around each turbine has been used to evaluate wind turbine wake recovery and corresponding harvested power. Results confirm the existence of two dominant recovery mechanisms, advection and flux of mean kinetic energy, which are modulated by the background thermal stratification. For the low-density arrangements advection dominates, while for the highly loaded wind farms the mean kinetic energy recovers through fluxes of mean kinetic energy. For those cases in between, a smooth balance of both mechanisms exists. From the results, a low-order model for the wind farms' harvested power as a function of thermal stratification and wind farm density has been developed, which has the potential to be used as an order-of-magnitude assessment tool.

  8. Theoretically optimal turbine resistance in very large wind farms

    NASA Astrophysics Data System (ADS)

    Zapata, Alejandro; Nishino, Takafumi; Delafin, Pierre-Luc

    2017-05-01

    In this paper we further investigate and validate the novel theoretical model of very large wind farms proposed recently by Nishino (J. Phys.: Conf. Ser. 753, 032054, 2016). One of the key features of the Nishino model is that a theoretically optimal turbine resistance (as well as optimal ‘turbine-scale’ and ‘farm-scale’ wind speed reduction rates) can be predicted analytically as a function of the farm density and the natural bottom friction observed before constructing the farm. To validate this theoretical model, a new set of 3D Reynolds-averaged Navier-Stokes (RANS) simulations are performed of a fully developed wind farm boundary layer over an aligned and staggered array of actuator discs with various disc resistance, inter-disc spacing and bottom roughness values. The results show that the theoretical model, which employs only one empirical model parameter, can be easily calibrated to predict very well the performance of various staggered arrays of actuator discs. This suggests the usefulness of the theoretical model not only for providing an upper limit to the performance of ideal large arrays but also for predicting the performance of realistic large arrays. The results also highlight the important fact that the optimal turbine resistance can be significantly smaller in a dense wind farm than in a sparse wind farm.

  9. Research on large-scale wind farm modeling

    NASA Astrophysics Data System (ADS)

    Ma, Longfei; Zhang, Baoqun; Gong, Cheng; Jiao, Ran; Shi, Rui; Chi, Zhongjun; Ding, Yifeng

    2017-01-01

    Due to intermittent and adulatory properties of wind energy, when large-scale wind farm connected to the grid, it will have much impact on the power system, which is different from traditional power plants. Therefore it is necessary to establish an effective wind farm model to simulate and analyze the influence wind farms have on the grid as well as the transient characteristics of the wind turbines when the grid is at fault. However we must first establish an effective WTGs model. As the doubly-fed VSCF wind turbine has become the mainstream wind turbine model currently, this article first investigates the research progress of doubly-fed VSCF wind turbine, and then describes the detailed building process of the model. After that investigating the common wind farm modeling methods and pointing out the problems encountered. As WAMS is widely used in the power system, which makes online parameter identification of the wind farm model based on off-output characteristics of wind farm be possible, with a focus on interpretation of the new idea of identification-based modeling of large wind farms, which can be realized by two concrete methods.

  10. Whole-farm nitrogen balance on western dairy farms.

    PubMed

    Spears, R A; Kohn, R A; Young, A J

    2003-12-01

    Environmental legislation has made it necessary for livestock producers to be able to quantify and adjust the N balance on their farms. Whole-farm N balance and efficiencies were computed for 41 commercial dairies in Utah and Idaho using the University of Maryland Nutrient Balancer. The average N balance, or unaccounted for N, was 81 tonnes per year for the average herd size of 466 cows with 35.8% of the inputs accounted for in the outputs. The major inputs for farms that grew crops (n = 23, herd size = 284 total cows) were imported feed (57.4% of all inputs) and nitrogen fixation (30% of inputs). The major outputs were animal products (primarily milk and some meat, 80% of outputs). For farms that grew no crops (n = 18, herd size = 700 total cows), 98% of the inputs were from imported feed. Of the outputs, 57% of the N was in animal products and 42.9% in manure and compost. Whole-farm balance per product for those farms that grew crops was most affected by herd N utilization efficiency (kg feed N per kg product N), crop N utilization efficiency, and availability of manure N applied to crops, while manure N storage efficiency was of lesser importance. For farms that grew no crops, whole-farm N balance per product was most affected by herd N utilization efficiency and manure N storage efficiency. Maximizing conversion of feed N to product N was the best way to reduce whole-farm N balance.

  11. Transient climate simulations of the deglaciation 21-9 thousand years before present (version 1) - PMIP4 Core experiment design and boundary conditions

    NASA Astrophysics Data System (ADS)

    Ivanovic, Ruza F.; Gregoire, Lauren J.; Kageyama, Masa; Roche, Didier M.; Valdes, Paul J.; Burke, Andrea; Drummond, Rosemarie; Peltier, W. Richard; Tarasov, Lev

    2016-07-01

    The last deglaciation, which marked the transition between the last glacial and present interglacial periods, was punctuated by a series of rapid (centennial and decadal) climate changes. Numerical climate models are useful for investigating mechanisms that underpin the climate change events, especially now that some of the complex models can be run for multiple millennia. We have set up a Paleoclimate Modelling Intercomparison Project (PMIP) working group to coordinate efforts to run transient simulations of the last deglaciation, and to facilitate the dissemination of expertise between modellers and those engaged with reconstructing the climate of the last 21 000 years. Here, we present the design of a coordinated Core experiment over the period 21-9 thousand years before present (ka) with time-varying orbital forcing, greenhouse gases, ice sheets and other geographical changes. A choice of two ice sheet reconstructions is given, and we make recommendations for prescribing ice meltwater (or not) in the Core experiment. Additional focussed simulations will also be coordinated on an ad hoc basis by the working group, for example to investigate more thoroughly the effect of ice meltwater on climate system evolution, and to examine the uncertainty in other forcings. Some of these focussed simulations will target shorter durations around specific events in order to understand them in more detail and allow for the more computationally expensive models to take part.

  12. Does training with traditionally presented and virtually simulated tasks elicit differing changes in object interaction kinematics in persons with upper extremity hemiparesis?

    PubMed

    Fluet, Gerard G; Merians, Alma S; Qiu, Qinyin; Rohafaza, Maryam; VanWingerden, Anita M; Adamovich, S V

    2015-06-01

    To contrast changes in clinical and kinematic measures of upper extremity movement in response to virtually simulated and traditionally presented rehabilitation interventions in persons with upper extremity hemiparesis due to chronic stroke. Non-randomized controlled trial. Ambulatory research facility. Subjects were a volunteer sample of twenty one community-dwelling adults (mean age: 51 ± 12 years) with residual hemiparesis due to stroke more than 6 months before enrollment (mean: 74 ± 48 months), recruited at support groups. Partial range, against gravity shoulder movement and at least 10° of active finger extension were required for inclusion. All subjects completed the study without adverse events. A 2 weeks, 24-hour program of robotic/virtually simulated, arm and finger rehabilitation activities was compared to the same dose of traditionally presented arm and finger activities. Subjects in both groups demonstrated statistically significant improvements in the ability to interact with real-world objects as measured by the Wolf Motor Function Test (P = 0.01). The robotic/virtually simulated activity (VR) group but not the traditional, repetitive task practice (RTP) group demonstrated significant improvements in peak reaching velocity (P = 0.03) and finger extension excursion (P = 0.03). Both groups also demonstrated similar improvements in kinematic measures of reaching and grasping performance such as increased shoulder and elbow excursion along with decreased trunk excursion. Kinematic measurements identified differing adaptations to training that clinical measurements did not. These adaptations were targeted in the design of four of the six simulations performed by the simulated activity group. Finer grained measures may be necessary to accurately depict the relative benefits of dose matched motor interventions.

  13. Are large farms more efficient? Tenure security, farm size and farm efficiency: evidence from northeast China

    NASA Astrophysics Data System (ADS)

    Zhou, Yuepeng; Ma, Xianlei; Shi, Xiaoping

    2017-04-01

    How to increase production efficiency, guarantee grain security, and increase farmers' income using the limited farmland is a great challenge that China is facing. Although theory predicts that secure property rights and moderate scale management of farmland can increase land productivity, reduce farm-related costs, and raise farmer's income, empirical studies on the size and magnitude of these effects are scarce. A number of studies have examined the impacts of land tenure or farm size on productivity or efficiency, respectively. There are also a few studies linking farm size, land tenure and efficiency together. However, to our best knowledge, there are no studies considering tenure security and farm efficiency together for different farm scales in China. In addition, there is little study analyzing the profit frontier. In this study, we particularly focus on the impacts of land tenure security and farm size on farm profit efficiency, using farm level data collected from 23 villages, 811 households in Liaoning in 2015. 7 different farm scales have been identified to further represent small farms, median farms, moderate-scale farms, and large farms. Technical efficiency is analyzed with stochastic frontier production function. The profit efficiency is regressed on a set of explanatory variables which includes farm size dummies, land tenure security indexes, and household characteristics. We found that: 1) The technical efficiency scores for production efficiency (average score = 0.998) indicate that it is already very close to the production frontier, and thus there is little room to improve production efficiency. However, there is larger space to raise profit efficiency (average score = 0.768) by investing more on farm size expansion, seed, hired labor, pesticide, and irrigation. 2) Farms between 50-80 mu are most efficient from the viewpoint of profit efficiency. The so-called moderate-scale farms (100-150 mu) according to the governmental guideline show no

  14. Involvement of Wives in Farm Tasks as Related to Characteristics of the Farm, the Family and Work Off the Farm.

    ERIC Educational Resources Information Center

    Wilkening, Eugene A.; Ahrens, Nancy

    In an attempt to determine the basis of the farm wife's involvement in farm tasks, hypotheses regarding farm size and type, family cycle and wife's age, off-farm work of husband or wife, and family educational levels were tested in a 1978 random questionnaire survey of 532 Wisconsin farm families. As expected, wives were more involved with farm…

  15. Designing the automatic milking farm in a hot climate.

    PubMed

    Halachmi, I

    2004-03-01

    A mathematical simulation model was used to assist 5 farmers in developing design criteria for inclusion of robotic milking systems in each farm situation. The barn layout influences arrivals of cows to the milking robot as well as other cow traffic and must be carefully planned. Each farmer had individual objectives and consequently unique design criteria that determined the optimal solution. Planning factors addressed by simulations on these farms included: 1) optimal cow cooling locations; 2) optimal facility allocation in expanding dairies; 3) concentrate feeder locations and feeding management; 4) number of feeders--based on expected rations; 5) use of a robot in an open cowshed without free stalls; 6) number of robots needed, currently and in the future; 7) eight robots working in harmony; 8) robot locations that allow for expansion; 9) floor space needed in each barn section including maternity and veterinary treatment areas; 10) location of bottlenecks that limit efficiency or expansion; and 11) cow traffic routine as affected by management practices, feed allocation, and farm layout. The simulation allowed farmers to receive a course in managing a "virtual robotic milking farm" before installation of the barn. Therefore, each could be more confident that his future barn would work properly under his unique local conditions and management practices. One farm checked 2 yr after construction achieved an average daily robot utilization of 84%, nearly matching the 85% projected before the barn was built. Important variables considered in the simulations were facility allocation, cow space needed in each farm area, robot utilization, number of cows, milk yield, milk flow rate, feeding method and timing, robot location and orientation, and farm physical layout.

  16. Wind-farms in shallow conventionally neutral boundary layers: effects of transition and gravity waves on energy budget

    NASA Astrophysics Data System (ADS)

    Meyers, Johan; Allaerts, Dries

    2016-11-01

    Conventionally neutral boundary layers (CNBL) often arise in offshore conditions. In these situations the neutral boundary layer is capped by a strong inversion layer and a stably stratified free atmosphere aloft. We use large-eddy simulations to investigate the interaction between a CNBL and a large wind farm. Following the approach of Allaerts & Meyers (2015), a set of equilibrium CNBLs are produced in a precursor simulation, with a height of approx. 300, 500, and 1000m, respectively. These are used at the inlet of a large wind-farm with a fetch of 15 km, and 20 rows of turbines. We find that above the farm, an internal boundary layer (IBL) develops. For the two lower CNBL cases, the IBL growth is stopped by the overlying capping inversion. Moreover, the upward displacement of the CNBL excites gravity waves in the inversion layer and the free atmosphere above. For the lower CNBL cases, these waves induce significant pressure gradients in the farm. A detailed energy budget analysis of the CNBL is further presented. The authors acknowledge support from the European Research Council (FP7-Ideas, Grant No. 306471).

  17. Causal pathways linking Farm to School to childhood obesity prevention.

    PubMed

    Joshi, Anupama; Ratcliffe, Michelle M

    2012-08-01

    Farm to School programs are rapidly gaining attention as a potential strategy for preventing childhood obesity; however, the causal linkages between Farm to School activities and health outcomes are not well documented. To capitalize on the increased interest in and momentum for Farm to School, researchers and practitioners need to move from developing and implementing evidence informed programs and policies to ones that are evidence-based. The purpose of this article is to outline a framework for facilitating an evidence base for Farm to School programs and policies through a systematic and coordinated approach. Employing the concepts of causal pathways, the authors introduce a proposed framework for organizing and systematically testing out multiple hypotheses (or potential causal links) for how, why, and under what conditions Farm to School Inputs and Activities may result in what Outputs, Effects, and Impacts. Using the causal pathways framework may help develop and test competing hypotheses, identify multicausality, strength, and interactions of causes, and discern the difference between catalysts and causes. In this article, we introduce causal pathways, present menus of potential independent and dependent variables from which to create and test causal pathways linking Farm to School interventions and their role in preventing childhood obesity, discuss their applicability to Farm to School research and practice, and outline proposed next steps for developing a coordinated research framework for Farm to School programs.

  18. Modelling of Wind Turbine Loads nearby a Wind Farm

    NASA Astrophysics Data System (ADS)

    Roscher, B.; Werkmeister, A.; Jacobs, G.; Schelenz, R.

    2017-05-01

    Each wind turbine experiences a variety of loads during its lifetime, especially inside a wind farm due to the wake effect between the turbines. This paper describes a possibility to observe a load spectrum while considering wake effects in a wind farm by through the turbulence intensity. The turbulence intensity is distributed along the wind rose of Alpha Ventus. For each turbulence intensity, a Weibull characteristic is calculated. The resulting wind fields are used to determine the loads through a multibody simulation of an imaginary wind turbine located at FINO-1, representing a closely placed wind turbine at the outer edge of a wind farm. These loads are analyzed and summed up. As expected, the change of the turbulence intensity due to the wake effect has an impact on the internal loading of a wind turbine inside a wind farm. Based on the assumed loading conditions, the maximum loads increased by a factor of almost 2.5.

  19. Short-term Wind Forecasting at Wind Farms located on Mountainous Terrains

    NASA Astrophysics Data System (ADS)

    Kirkil, Gokhan

    2016-04-01

    Power uncertainty and fluctuations are recognized as major challenges for expanding wind energy. Here we aim at better understanding and characterizing fluctuations in wind power caused by rapid changes in wind resource. By means of Large Eddy Simulations (LES), we expect to gain new knowledge about the sources of spatial and temporal variability of wind fluctuations such as different configurations of wind turbines and complex topography. We will present the recent progress on our LES simulations for a wind farm located near a mountainous terrain. We performed multi-scale simulations using WRF's different Planetary Boundary Layer (PBL) parameterizations as well as Large Eddy Simulation (LES). WRF ensembles with different PBL parameterizations showed little spread for wind speed forecasts. LES models improved the forecasts. Statistical error analysis is performed and ramp events are analyzed.

  20. Data-Mining-Based Intelligent Differential Relaying for Transmission Lines Including UPFC and Wind Farms.

    PubMed

    Jena, Manas Kumar; Samantaray, Subhransu Ranjan

    2016-01-01

    This paper presents a data-mining-based intelligent differential relaying scheme for transmission lines, including flexible ac transmission system device, such as unified power flow controller (UPFC) and wind farms. Initially, the current and voltage signals are processed through extended Kalman filter phasor measurement unit for phasor estimation, and 21 potential features are computed at both ends of the line. Once the features are extracted at both ends, the corresponding differential features are derived. These differential features are fed to a data-mining model known as decision tree (DT) to provide the final relaying decision. The proposed technique has been extensively tested for single-circuit transmission line, including UPFC and wind farms with in-feed, double-circuit line with UPFC on one line and wind farm as one of the substations with wide variations in operating parameters. The test results obtained from simulation as well as in real-time digital simulator testing indicate that the DT-based intelligent differential relaying scheme is highly reliable and accurate with a response time of 2.25 cycles from the fault inception.

  1. Simulated Agribusiness.

    ERIC Educational Resources Information Center

    Salisbury, Howard G., III

    "Simulated Agribusiness" is designed to provide the student with a role playing situation dealing with the complexities and problems of modern agriculture. It is a competitive game played on a hypothetical mid-latitude diversified farm in a capitalistic system. The player is faced with a series of decisions which will determine his success or…

  2. Mixed crop-livestock systems: an economic and environmental-friendly way of farming?

    PubMed

    Ryschawy, J; Choisis, N; Choisis, J P; Joannon, A; Gibon, A

    2012-10-01

    Intensification and specialisation of agriculture in developed countries enabled productivity to be improved but had detrimental impacts on the environment and threatened the economic viability of a huge number of farms. The combination of livestock and crops, which was very common in the past, is assumed to be a viable alternative to specialised livestock or cropping systems. Mixed crop-livestock systems can improve nutrient cycling while reducing chemical inputs and generate economies of scope at farm level. Most assumptions underlying these views are based on theoretical and experimental evidence. Very few assessments of their environmental and economic advantages have nevertheless been undertaken in real-world farming conditions. In this paper, we present a comparative assessment of the environmental and economic performances of mixed crop-livestock farms v. specialised farms among the farm population of the French 'Coteaux de Gascogne'. In this hilly region, half of the farms currently use a mixed crop-livestock system including beef cattle and cash crops, the remaining farms being specialised in either crops or cattle. Data were collected through an exhaustive survey of farms located in our study area. The economic performances of farming systems were assessed on 48 farms on the basis of (i) overall gross margin, (ii) production costs and (iii) analysis of the sensitivity of gross margins to fluctuations in the price of inputs and outputs. The environmental dimension was analysed through (i) characterisation of farmers' crop management practices, (ii) analysis of farm land use diversity and (iii) nitrogen farm-gate balance. Local mixed crop-livestock farms did not have significantly higher overall gross margins than specialised farms but were less sensitive than dairy and crop farms to fluctuations in the price of inputs and outputs considered. Mixed crop-livestock farms had lower costs than crop farms, while beef farms had the lowest costs as they are grass

  3. Evaluation of organic, conventional and intensive beef farm systems: health, management and animal production.

    PubMed

    Blanco-Penedo, I; López-Alonso, M; Shore, R F; Miranda, M; Castillo, C; Hernández, J; Benedito, J L

    2012-09-01

    The overall aim of the present study was to analyse and compare organic beef cattle farming in Spain with intensive and conventional systems. An on-farm study comparing farm management practices and animal health was carried out. The study also focussed on a slaughterhouse analysis by comparing impacts on the safety and quality of the cattle products. Twenty-four organic and 26 conventional farms were inspected, and farmers responded to a questionnaire that covered all basic data on their husbandry practices, farm management, veterinary treatments and reproductive performance during 2007. Furthermore, data on the hygiene and quality of 244, 2596 and 3021 carcasses of calves from organic, intensive and conventional farms, respectively, were retrieved from the official yearbook (2007) of a slaughterhouse. Differences found between organic and conventional farms across the farm analysis did not substantially reflect differences between both farm types in the predominant diseases that usually occur on beef cattle farms. However, calves reared organically presented fewer condemnations at slaughter compared with intensive and to a lesser extent with conventionally reared calves. Carcass performance also reflected differences between farm type and breed and was not necessarily better in organic farms.

  4. Occurrence of methicillin-resistant Staphylococcus aureus in farm workers and the livestock environment in Mecklenburg-Western Pomerania, Germany

    PubMed Central

    2014-01-01

    Background Livestock-associated methicillin-resistant Staphylococcus aureus (LA-MRSA) has a wide host range and is transmissible to humans, especially to those with close contact to colonized animals. This study presents the first data on the occurrence of MRSA in farm workers and livestock farms (pig, cattle and poultry) in the federal state of Mecklenburg-Western Pomerania in northeast Germany. 78 farm workers at pig farms, cattle farms and poultry farms were tested for MRSA via pooled nasal and pharyngeal swabs. Additionally, from each of the 34 participating farms (17 pig farms, 11 cattle farms, 6 poultry farms) five dust samples were taken from the direct surroundings of the animals. Furthermore, oropharyngeal swabs were additionally taken from 10 animals per poultry farm. Isolated MRSA strains were characterized and confirmed using PCR and spa typing. Resistance patterns were obtained using the broth microdilution assay. Results In total, 20 of 78 (25.6%; 95% CI:17.3-36.3) farm workers were positive for MRSA. All MRSA-positive workers were employed at pig farms. Six of 17 (35.3%; 95% CI:17.3-58.7) pooled dust samples from pig farms were also positive. Overall, six spa types were identified, of which t034 predominated. All strains belonged to LA-MRSA CC398 and were resistant to tetracycline. Resistance to lincosamides, macrolides, fluoroquinolones and aminoglycosides was present in some strains. Three farm workers harbored the identical spa type and antimicrobial resistance pattern found in the corresponding dust sample. Neither workers, dust samples from cattle and poultry farms, nor oropharyngeal poultry swabs tested positive for MRSA. Conclusions The present study emphasizes the importance of MRSA on pig farms and pig-farm workers in the rural region of Mecklenburg-Western Pomerania, whereas LA-MRSA could not be isolated from cattle and poultry farms. PMID:25142727

  5. Occurrence of methicillin-resistant Staphylococcus aureus in farm workers and the livestock environment in Mecklenburg-Western Pomerania, Germany.

    PubMed

    Dahms, Carmen; Hübner, Nils-Olaf; Cuny, Christiane; Kramer, Axel

    2014-08-21

    Livestock-associated methicillin-resistant Staphylococcus aureus (LA-MRSA) has a wide host range and is transmissible to humans, especially to those with close contact to colonized animals. This study presents the first data on the occurrence of MRSA in farm workers and livestock farms (pig, cattle and poultry) in the federal state of Mecklenburg-Western Pomerania in northeast Germany. 78 farm workers at pig farms, cattle farms and poultry farms were tested for MRSA via pooled nasal and pharyngeal swabs. Additionally, from each of the 34 participating farms (17 pig farms, 11 cattle farms, 6 poultry farms) five dust samples were taken from the direct surroundings of the animals. Furthermore, oropharyngeal swabs were additionally taken from 10 animals per poultry farm. Isolated MRSA strains were characterized and confirmed using PCR and spa typing. Resistance patterns were obtained using the broth microdilution assay. In total, 20 of 78 (25.6%; 95% CI:17.3-36.3) farm workers were positive for MRSA. All MRSA-positive workers were employed at pig farms. Six of 17 (35.3%; 95% CI:17.3-58.7) pooled dust samples from pig farms were also positive. Overall, six spa types were identified, of which t034 predominated. All strains belonged to LA-MRSA CC398 and were resistant to tetracycline. Resistance to lincosamides, macrolides, fluoroquinolones and aminoglycosides was present in some strains. Three farm workers harbored the identical spa type and antimicrobial resistance pattern found in the corresponding dust sample. Neither workers, dust samples from cattle and poultry farms, nor oropharyngeal poultry swabs tested positive for MRSA. The present study emphasizes the importance of MRSA on pig farms and pig-farm workers in the rural region of Mecklenburg-Western Pomerania, whereas LA-MRSA could not be isolated from cattle and poultry farms.

  6. Farm Household Survival Strategies and Diversification on Marginal Farms

    ERIC Educational Resources Information Center

    Meert, H.; Van Huylenbroeck, G.; Vernimmen, T.; Bourgeois, M.; van Hecke, E.

    2005-01-01

    On marginal farms, and in agriculture in general, sustainability is largely guaranteed by a broad range of survival strategies, closely interlinked and embedded in the household structure of typical family farms. This paper reports results of a socio-economic study carried out among Belgian farmers, focusing specifically on the opportunities…

  7. Analysis of Farm Records. Teacher Edition. Farm Business Management Series.

    ERIC Educational Resources Information Center

    Oklahoma State Dept. of Vocational and Technical Education, Stillwater. Curriculum and Instructional Materials Center.

    This curriculum guide for the Oklahoma Farm Business Management Program contains three instructional units that teach students how to interpret farm records to get optimum use of facilities and maximize profits. Each unit of instruction includes some or all of these components: performance objectives, suggested activities for the instructor,…

  8. Whole Farm Nutrient Balance Calculator for New York Dairy Farms

    ERIC Educational Resources Information Center

    Soberon, Melanie A.; Ketterings, Quirine M.; Rasmussen, Caroline N.; Czymmek, Karl J.

    2013-01-01

    Nutrient loss and accumulation as well as associated environmental degradation have been a concern for animal agriculture for many decades. Federal and New York (NY) regulations apply to Concentrated Animal Feeding Operations and a comprehensive nutrient management plan (CNMP) is required for regulated farms. The whole farm nutrient mass balance…

  9. Whole Farm Nutrient Balance Calculator for New York Dairy Farms

    ERIC Educational Resources Information Center

    Soberon, Melanie A.; Ketterings, Quirine M.; Rasmussen, Caroline N.; Czymmek, Karl J.

    2013-01-01

    Nutrient loss and accumulation as well as associated environmental degradation have been a concern for animal agriculture for many decades. Federal and New York (NY) regulations apply to Concentrated Animal Feeding Operations and a comprehensive nutrient management plan (CNMP) is required for regulated farms. The whole farm nutrient mass balance…

  10. Farm Household Survival Strategies and Diversification on Marginal Farms

    ERIC Educational Resources Information Center

    Meert, H.; Van Huylenbroeck, G.; Vernimmen, T.; Bourgeois, M.; van Hecke, E.

    2005-01-01

    On marginal farms, and in agriculture in general, sustainability is largely guaranteed by a broad range of survival strategies, closely interlinked and embedded in the household structure of typical family farms. This paper reports results of a socio-economic study carried out among Belgian farmers, focusing specifically on the opportunities…

  11. Economic Indicators of the Farm Sector. Farm Sector Review, 1985.

    ERIC Educational Resources Information Center

    Economic Research Service (USDA), Washington, DC.

    Farm production rose 6 percent in 1985 due to record high yields in corn, soybeans, cotton, and several other crops. While United States consumption increased slightly, exports of farm products fell 23 percent in value and 19 percent in volume. Net cash income increased 12 percent due to increased output, lower cash expenses, and unusually high…

  12. Farm Women, Farming Systems, and Agricultural Structure: Suggestions for Scholarship.

    ERIC Educational Resources Information Center

    Flora, Cornelia Butler

    1981-01-01

    Suggests research agenda to analyze the class struggle occurring with farm women. Views the household as the unit of analysis, both internally from a farming-systems perspective and externally as responding to shifts in policy and technology. Available from: Rural Sociological Society, 325 Morgan Hall, University of Tennessee, Knoxville, TN 37916.…

  13. Farm-Size Structure and Off-Farm Income and Employment Generation in the North Central Region.

    ERIC Educational Resources Information Center

    Heady, Earl O.; Sonka, Steven T.

    The relationship between size of farm and the welfare of farm and nonfarm society was examined in terms of total income in the farm sector, the number and size of farms, income per farm, secondary income generation, and consumer food costs using four alternative farm structures: large farm (gross farm sales of at least $40,000); medium farm (gross…

  14. Wind Farm Feasibility Study

    SciTech Connect

    Richard Curry; Erik Foley; DOE Project Officer - Keith Bennett

    2007-07-11

    Saint Francis University has assessed the Swallow Farm property located in Shade Township, Somerset County, Pennsylvania as a potential wind power development site. Saint Francis worked with McLean Energy Partners to have a 50-meter meteorological tower installed on the property in April 2004 and continues to conduct a meteorological assessment of the site. Results suggest a mean average wind speed at 80 meters of 17 mph with a net capacity factor of 31 - 33%. Approximate electricity generation capacity of the project is 10 megawatts. Also, the University used matching funds provided by the federal government to contract with ABR, Inc. to conduct radar studies of nocturnal migration of birds and bats during the migrations seasons in the Spring and Fall of 2005 with a mean nocturnal flight altitude of 402 meters with less than 5% of targets at altitudes of less than 125 meters. The mean nocturnal passage rate was 166 targets/km/h in the fall and 145 targets/km/h in the spring. Lastly, University faculty and students conducted a nesting bird study May - July 2006. Seventy-three (73) species of birds were observed with 65 determined to be breeding or potentially breeding species; this figure represents approximately 30% of the 214 breeding bird species in Pennsylvania. No officially protected avian species were determined to be nesting at Swallow Farm.

  15. Economic and phosphorus-related effects of precision feeding and forage management at a farm scale.

    PubMed

    Ghebremichael, L T; Cerosaletti, P E; Veith, T L; Rotz, C A; Hamlett, J M; Gburek, W J

    2007-08-01

    Structural best management practices were implemented throughout the Cannonsville Reservoir Watershed (CRW) in an effort to reduce P losses to the reservoir. Yet long-term water quality control efforts within CRW are hindered by continuous P build-up in the soils resulting from dairy farm P imports exceeding exports. Addressing the P imbalance problems and maintaining economic viability of the farms requires a system-level redesign of farm management. One possible innovative strategy, precision feed management (PFM), reduces soil-P build-up by limiting feed and fertilizer purchases, and increasing high-quality homegrown forage production. This study applied the integrated farm system model (IFSM) to 2 CRW dairy farms to quantify the benefits of a PFM farm planning strategy in controlling P imbalance problems, and maintaining farm profit-ability and reducing off-farm P losses. The IFSM accurately simulated the 2 farms based on farm data supplied by farm planners; these scenarios were used as the baseline conditions. The IFSM simulations of more accurate feeding of P (based on P required in animal diets) integrated with increased productivity of grass-forage and increased proportion of forage in the diet reduced the P imbalance of 1 farm from 5.3 to 0.5 kg/ ha and from 9.6 to 0.0 kg/ha for the second farm. For both farms, soluble P lost to the environment was reduced by 18%. Feed supplement purchases declined by 7.5 kg/cow per year for dietary mineral P, and by 1.04 and 1.29 t/cow per year for protein concentrates through adoption of the PFM system. Moreover, when a land management practice of converting corn to grass was coupled with the precision feeding of P and improved forage management, IFSM predicted reductions of 5.8 and 9.3 kg/ha of converted land sediment-bound P in erosion loss each year. The model predicted slight purchase increases in corn grain to offset reductions in corn silage production and feeding rates, but no appreciable change in the farm P

  16. Transient climate simulation from the Maunder Minimum to present day using prescribed changes in GHG, total/spectral solar irradiance and ozone

    NASA Astrophysics Data System (ADS)

    Spangehl, Thomas; Cubasch, Ulrich; Schimanke, Semjon

    A fully coupled AO-GCM including representation of the middle atmosphere is used for tran-sient simulation of climate from 1630 to 2000 AD. For better representation of changes in the UV/visible part of the solar spectrum an improved short-wave radiation scheme is implemented. The model is driven by changes in GHG concentrations, solar activity and volcanic eruptions. Solar variability is introduced via changes in total/spectral solar irradiance (TSI/SSI) and pre-scribed changes in stratospheric ozone. The secular trend in TSI is in the range of 0.1 percent increase from Maunder Minimum to present-day. Volcanic eruptions are represented via abrupt reduction in TSI. With the applied forcings the model does not simulate a clear reduction of the annual Northern Hemisphere (NH) mean near surface temperature during Maunder Minimum. By contrast the Dalton Minimum is characterized by distinct cooling and there is a significant raise of NH mean near surface temperature until the end of the 20th century. Focusing on the North Atlantic/European region the winter mean near surface temperature change pat-tern from Late Maunder Minimum (1675-1715) to present-day (1960-1990) reveals maximum warming over north-eastern Europe and cooling over the western North Atlantic with maxi-mum cooling west of Greenland. These changes can partly be explained by a shift of the NAO towards a more positive phase. The simulated changes in tropospheric circulation are discussed with special emphasize on the role of the solar forcing. Besides the stratospheric solar forcing which may affect NAO variability via downward propagation of the solar signal from the strato-sphere to the troposphere the magnitude of the secular trend in TSI might play a role. For the period from Maunder Minimum to present-day the simulation shows less near surface temper-ature increase especially over arctic regions when compared to simulations performed with the same model including the standard radiation scheme but

  17. Farming and the fate of wild nature.

    PubMed

    Green, Rhys E; Cornell, Stephen J; Scharlemann, Jörn P W; Balmford, Andrew

    2005-01-28

    World food demand is expected to more than double by 2050. Decisions about how to meet this challenge will have profound effects on wild species and habitats. We show that farming is already the greatest extinction threat to birds (the best known taxon), and its adverse impacts look set to increase, especially in developing countries. Two competing solutions have been proposed: wildlife-friendly farming (which boosts densities of wild populations on farmland but may decrease agricultural yields) and land sparing (which minimizes demand for farmland by increasing yield). We present a model that identifies how to resolve the trade-off between these approaches. This shows that the best type of farming for species persistence depends on the demand for agricultural products and on how the population densities of different species on farmland change with agricultural yield. Empirical data on such density-yield functions are sparse, but evidence from a range of taxa in developing countries suggests that high-yield farming may allow more species to persist.

  18. An economic decision-making support system for selection of reproductive management programs on dairy farms.

    PubMed

    Giordano, J O; Fricke, P M; Wiltbank, M C; Cabrera, V E

    2011-12-01

    Because the reproductive performance of lactating dairy cows influences the profitability of dairy operations, predicting the future reproductive and economic performance of dairy herds through decision support systems would be valuable to dairy producers and consultants. In this study, we present a highly adaptable tool created based on a mathematical model combining Markov chain simulation with partial budgeting to obtain the net present value (NPV; $/cow per year) of different reproductive management programs. The growing complexity of reproductive programs used by dairy farms demands that new decision support systems precisely reflect the events that occur on the farm. Therefore, the model requires productive, reproductive, and economic input data used for simulation of farm conditions to account for all factors related to reproductive management that increase costs and generate revenue. The economic performance of 3 different reproductive programs can be simultaneously compared with the current model. A program utilizing 100% visual estrous detection (ED) for artificial insemination (AI) is used as a baseline for comparison with 2 other programs that may include 100% timed AI (TAI) as well as any combination of TAI and ED. A case study is presented in which the model was used to compare 3 different reproductive management strategies (100% ED baseline compared with two 100% TAI options) using data from a commercial farm in Wisconsin. Sensitivity analysis was then used to assess the effect of varying specific reproductive parameters on the NPV. Under the simulated conditions of the case study, the model indicated that the two 100% TAI programs were superior to the 100% ED program and, of the 100% TAI programs, the one with the higher conception rate (CR) for resynchronized AI services was economically superior despite having higher costs and a longer interbreeding interval. A 4% increase in CR for resynchronized AI was sufficient for the inferior 100% TAI to

  19. Food and farm products surveillance

    SciTech Connect

    Poston, T.M.

    1995-06-01

    This section of the 1994 Hanford Site Environmental Report summarizes the radiological analyses performed on food and farm samples collected during 1994. The food and farm sampling design addresses the potential influence of Hanford Site releases. Details of the sampling design and radionuclides analyzed are included in this section.

  20. Grieving for the Family Farm.

    ERIC Educational Resources Information Center

    Zeller, Simon H.

    1986-01-01

    Reviews impact of recent agricultural trends in South Dakota. Outlines Kubler-Ross' stages of grief/adaptation that farm families must negotiate as they cope with the trauma of the loss of their farms. Indicates service providers must overcome farmers' mistrust for human welfare services and reach out to this vulnerable population. (NEC)

  1. Grieving for the Family Farm.

    ERIC Educational Resources Information Center

    Zeller, Simon H.

    1986-01-01

    Reviews impact of recent agricultural trends in South Dakota. Outlines Kubler-Ross' stages of grief/adaptation that farm families must negotiate as they cope with the trauma of the loss of their farms. Indicates service providers must overcome farmers' mistrust for human welfare services and reach out to this vulnerable population. (NEC)

  2. Visit a Farm? Surely Not!

    ERIC Educational Resources Information Center

    Graham, Bill

    2012-01-01

    Popular myth has it that visiting a farm can be dangerous, but there are only a few occasions when children have become ill during a school visit to a farm. Simple, sensible precautions, including wearing appropriate clothing, such as trousers and wellington boots (if wet) or sensible shoes, and careful hand-washing, are all that is required. The…

  3. Visit a Farm? Surely Not!

    ERIC Educational Resources Information Center

    Graham, Bill

    2012-01-01

    Popular myth has it that visiting a farm can be dangerous, but there are only a few occasions when children have become ill during a school visit to a farm. Simple, sensible precautions, including wearing appropriate clothing, such as trousers and wellington boots (if wet) or sensible shoes, and careful hand-washing, are all that is required. The…

  4. Comparing technical efficiency of farms with an automatic milking system and a conventional milking system.

    PubMed

    Steeneveld, W; Tauer, L W; Hogeveen, H; Oude Lansink, A G J M

    2012-12-01

    other than higher capital costs, the use of AMS rather than a CMS does not affect farm efficiency and that the learning costs to use an AMS are not present as measured by any fall in technical efficiency.

  5. Assessment of the performance of CORDEX-SA experiments in simulating seasonal mean temperature over the Himalayan region for the present climate: Part I

    NASA Astrophysics Data System (ADS)

    Nengker, T.; Choudhary, A.; Dimri, A. P.

    2017-03-01

    The ability of an ensemble of five regional climate models (hereafter RCMs) under Coordinated Regional Climate Downscaling Experiments-South Asia (hereafter, CORDEX-SA) in simulating the key features of present day near surface mean air temperature (Tmean) climatology (1970-2005) over the Himalayan region is studied. The purpose of this paper is to understand the consistency in the performance of models across the ensemble, space and seasons. For this a number of statistical measures like trend, correlation, variance, probability distribution function etc. are applied to evaluate the performance of models against observation and simultaneously the underlying uncertainties between them for four different seasons. The most evident finding from the study is the presence of a large cold bias (-6 to -8 °C) which is systematically seen across all the models and across space and time over the Himalayan region. However, these RCMs with its fine resolution perform extremely well in capturing the spatial distribution of the temperature features as indicated by a consistently high spatial correlation (greater than 0.9) with the observation in all seasons. In spite of underestimation in simulated temperature and general intensification of cold bias with increasing elevation the models show a greater rate of warming than the observation throughout entire altitudinal stretch of study region. During winter, the simulated rate of warming gets even higher at high altitudes. Moreover, a seasonal response of model performance and its spatial variability to elevation is found.

  6. Real time wind farm emulation using SimWindFarm toolbox

    NASA Astrophysics Data System (ADS)

    Topor, Marcel

    2016-06-01

    This paper presents a wind farm emulation solution using an open source Matlab/Simulink toolbox and the National Instruments cRIO platform. This work is based on the Aeolus SimWindFarm (SWF) toolbox models developed at Aalborg university, Denmark. Using the Matlab Simulink models developed in SWF, the modeling code can be exported to a real time model using the NI Veristand model framework and the resulting code is integrated as a hardware in the loop control on the NI 9068 platform.

  7. Environmental and economic comparisons of manure application methods in farming systems

    USDA-ARS?s Scientific Manuscript database

    Alternative methods for applying livestock manure to no-till soils involve environmental and economic trade-offs. A process-level farm simulation model (Integrated Farm System Model) was used to evaluate methods for applying liquid dairy (Bos taurus L.) and swine (Sus scrofa L.) manure including no...

  8. Hanford Tank Farms Vadose Zone, Addendum to the T Tank Farm Report

    SciTech Connect

    Spatz, Robert

    2000-07-01

    This addendum to the T Tank Farm Report (GJO-99-101-TARA, GJO-HAN-27) published in September 1999 incorporates the results of high-rate and repeat logging activities along with shape factor analysis of the logging incorporates the results of high-rate and repeat logging activities along with shape factor analysis of the logging data. A high-rate logging system was developed and deployed in the T Tank Farm to measure cesium-137 concentration levels in high gamma flux zones where the spectral gamma logging system was unable to collect usable data because of high dead times and detector saturation. This report presents additional data and revised visualizations of subsurface contaminant distribution in the T Tank Farm at the DOE Hanford Site in the state of Washington.

  9. Hanford Tank Farms Vadose Zone Addendum to the TY Tank Farm Report

    SciTech Connect

    Spatz, Robert

    2000-08-01

    This addendum to the TY Tank Farm Report (GJO-97-30-TAR, GJO-HAN-16) published in January 1998 incorporates the results of high-rate and repeat logging activities along with shape factor analysis of the logging data. A high-rate logging system was developed and deployed in the TY Tank Farm to measure cesium-137 concentration levels in high gamma flux zones where the spectral gamma logging system was unable to collect usable data because of high dead times and detector saturation. This report presents additional data and revised visualizations of subsurface contaminant distribution in the TY Tank Farm at the DOE Hanford Site in the state of Washington.

  10. Hanford Tank Farms Vadose Zone, Addendum to the BX Tank Farm Report

    SciTech Connect

    Pearson, A.W.

    2000-07-01

    This addendum to the BX Tank Farm Report (GJO-98-40-TARA, GJO-HAN-19) published in August 1998 incorporates the results of high-rate and repeat logging activities along with shape factor analysis of the logging data. A high-rate logging system was developed and deployed in the BX Tank Farm to measure cesium-137 concentration levels in high gamma flux zones where the spectral gamma logging system was unable to collect usable data because of high dead times and detector saturation. This report presents additional data and revised visualizations of subsurface contaminant distribution in the BX Tank Farm at the DOE Hanford Site in the state of Washington.

  11. Kinetic Monte Carlo simulation of the efficiency roll-off, emission color, and degradation of organic light-emitting diodes (Presentation Recording)

    NASA Astrophysics Data System (ADS)

    Coehoorn, Reinder; van Eersel, Harm; Bobbert, Peter A.; Janssen, Rene A. J.

    2015-10-01

    The performance of Organic Light Emitting Diodes (OLEDs) is determined by a complex interplay of the charge transport and excitonic processes in the active layer stack. We have developed a three-dimensional kinetic Monte Carlo (kMC) OLED simulation method which includes all these processes in an integral manner. The method employs a physically transparent mechanistic approach, and is based on measurable parameters. All processes can be followed with molecular-scale spatial resolution and with sub-nanosecond time resolution, for any layer structure and any mixture of materials. In the talk, applications to the efficiency roll-off, emission color and lifetime of white and monochrome phosphorescent OLEDs [1,2] are demonstrated, and a comparison with experimental results is given. The simulations show to which extent the triplet-polaron quenching (TPQ) and triplet-triplet-annihilation (TTA) contribute to the roll-off, and how the microscopic parameters describing these processes can be deduced properly from dedicated experiments. Degradation is treated as a result of the (accelerated) conversion of emitter molecules to non-emissive sites upon a triplet-polaron quenching (TPQ) process. The degradation rate, and hence the device lifetime, is shown to depend on the emitter concentration and on the precise type of TPQ process. Results for both single-doped and co-doped OLEDs are presented, revealing that the kMC simulations enable efficient simulation-assisted layer stack development. [1] H. van Eersel et al., Appl. Phys. Lett. 105, 143303 (2014). [2] R. Coehoorn et al., Adv. Funct. Mater. (2015), publ. online (DOI: 10.1002/adfm.201402532)

  12. Effect of nacelle on the wake meandering in Horns Rev wind farm

    NASA Astrophysics Data System (ADS)

    Yang, Xiaolei; Foti, Daniel; Sotiropoulos, Fotis

    2016-11-01

    Turbine wake meandering has considerable effects on the velocity deficit and turbulence intensity in the wake. However, the mechanism for wake meandering is still not well understood and low-order models cannot take into account the wake meandering effects accurately. A recent work by Kang, Yang and Sotiropoulos showed that the nacelle has a significant effect on the wake meandering of a hydrokinetic turbine. To examine the nacelle contributions to wake meandering and wake interactions in utility-scale wind farms, we simulate the atmospheric turbulent flow over the Horns Rev wind farm using large-eddy simulation with actuator type models. In a preliminary simulation on a coarse grid using actuator line model for turbine blades without a nacelle model, the computed power shows overall good agreement with field measurements. Fine grid simulations using an actuator surface model for turbine blades with and without a nacelle model are being carried out. The corresponding results will be presented with analysis on wake meandering dynamics using the technique proposed by Horward et al. and Foti et al.. This work was supported by DOE (DE-AC04-94AL85000), Xcel Energy (Grant RD4-13) and Sandia National Laboratories. Computational resources were provided by National Renewable Energy Laboratory and University of Minnesota Supercomputing Institute.

  13. Farm Hall: The Play

    NASA Astrophysics Data System (ADS)

    Cassidy, David C.

    2013-03-01

    It's July 1945. Germany is in defeat and the atomic bombs are on their way to Japan. Under the direction of Samuel Goudsmit, the Allies are holding some of the top German nuclear scientists-among them Heisenberg, Hahn, and Gerlach-captive in Farm Hall, an English country manor near Cambridge, England. As secret microphones record their conversations, the scientists are unaware of why they are being held or for how long. Thinking themselves far ahead of the Allies, how will they react to the news of the atomic bombs? How will these famous scientists explain to themselves and to the world their failure to achieve even a chain reaction? How will they come to terms with the horror of the Third Reich, their work for such a regime, and their behavior during that period? This one-act play is based upon the transcripts of their conversations as well as the author's historical work on the subject.

  14. California Solar Farms

    NASA Image and Video Library

    2015-04-02

    On February 15, 2015 the Desert Sunlight solar project in California’s Mojave Desert became operational. This image from NASA Terra spacecraft shows the 550-megawatt plant generates enough electricity to power 160,000 average homes. Covering an area of 16 km2, the 8.8 million cadmium telluride photovoltaic modules take advantage of the more than 300 days of sunshine. Desert Sunlight joins the similar-sized Topaz Solar Farm in San Luis Obispo County, CA, that became operational in June, 2014. The Desert Sunlight image (left) was acquired March 12, 2015 and is located at 33.8 degrees north, 115.4 degrees west; the Topaz image (right) was acquired September 11, 2014 and is located at 35.4 degrees north, 120.1 degrees west. Each image covers an area of 10.5 x 12 km. http://photojournal.jpl.nasa.gov/catalog/PIA19268

  15. Farm Business Records and Financial Statements. Teacher Edition. Farm Business Management Series.

    ERIC Educational Resources Information Center

    Oklahoma State Dept. of Vocational and Technical Education, Stillwater. Curriculum and Instructional Materials Center.

    Contained in this teacher's guide are the materials necessary to teach seven instructional units related to keeping farm business records and preparing financial statements. The following instructional units are presented: (1) orientation; (2) inventories; (3) journal entry; (4) enterprise accounting and supplemental records; (5) cash flow…

  16. From Bus Stop to Farm Village: The Farm Worker Programme in Zimbabwe.

    ERIC Educational Resources Information Center

    Auret, Diana

    This book documents the history, successes, and failures of Save the Children's farmworker program in Zimbabwe, 1981-98. The report explores workers' past and present living and working conditions on commercial farms and describes how the program promoted a progression from workers with a migrant mentality to the building of functional…

  17. CFD modeling of wind turbine wake in wind farms

    NASA Astrophysics Data System (ADS)

    Sun, Lijian

    Wind energy is one of the most common and preferred renewable energy sources. Accurate predictions of atmospheric boundary layer flow, wind turbine induced wakes and their interaction are essential to maximize wind power output and efficiently harness wind energy. In this dissertation, a computational fluid dynamics (CFD) flow model is developed utilizing a three dimensional weighted essentially non-oscillatory (WENO) high order Finite Volume Model system including Large Eddy Simulation (LES) and the Actuator Line Method (ALM). The developed model system is thus able to accurately capture and simulate wind turbine wakes and their interaction with the atmospheric boundary layer, thereby providing insight into the phenomenon of turbine wake interaction and its effect on the external aerodynamic loads on wind turbines. This enables the wind energy production to be maximized and also minimizes turbine fatigue loading in the evaluation of wind farm layouts. By using LES model to simulate the Atmospheric Boundary Layer flow rather than the Reynolds-Averaged Navier-Stokes (RANS) model, the error introduced by turbulence modeling is reduced. The Actuator Line Model, ALM, is used to model the rotor by replacing the rotor with radially distributed body forces. It is more accurate than the actuator disc method as it captures the influence of the blade tip vortices. It can focus on a larger portion of the wake without resolving the actual wind turbine blades' geometry, thereby reducing computational cost. It is suitable and a promising method for wind turbine wake simulation. Classic non-trivial turbulent benchmark cases are used to validate the high order LES algorithms. Simulation results are compared with available results whenever possible, with good agreement observed. Results for the atmospheric boundary layer under neutral conditions are presented. By using LES coupled with the Actuator Line model, simulation results are obtained for detailed wake flow features around

  18. Present and Future Projections of Habitat Suitability of the Asian Tiger Mosquito, a Vector of Viral Pathogens, from Global Climate Simulations.

    NASA Astrophysics Data System (ADS)

    Proestos, Y.; Christophides, G.; Erguler, K.; Tanarhte, M.; Waldock, J.; Lelieveld, J.

    2014-12-01

    Climate change can influence the transmission of vector borne diseases (VBDs) through altering the habitat suitability of insect vectors. Here we present global climate model simulations and evaluate the associated uncertainties in view of the main meteorological factors that may affect the distribution of the Asian Tiger mosquito (Aedes albopictus), which can transmit pathogens that cause Chikungunya, Dengue fever, yellow fever and various encephalitides. Using a general circulation model (GCM) at 50 km horizontal resolution to simulate mosquito survival variables including temperature, precipitation and relative humidity, we present both global and regional projections of the habitat suitability up to the middle of the 21st century. The model resolution of 50 km allows evaluation against previous projections for Europe and provides a basis for comparative analyses with other regions. Model uncertainties and performance are addressed in light of the recent CMIP5 ensemble climate model simulations for the RCP8.5 concentration pathway and using meteorological re-analysis data (ERA-Interim/ECMWF) for the recent past. Uncertainty ranges associated with the thresholds of meteorological variables that may affect the distribution of Ae. albopictus are diagnosed using fuzzy-logic methodology, notably to assess the influence of selected meteorological criteria and combinations of criteria that influence mosquito habitat suitability. From the climate projections for 2050, and adopting a habitat suitability index larger than 70%, we estimate that about 2.4 billion individuals in a land area of nearly 20 million square kilometres will potentially be exposed to Ae. albopictus. The synthesis of fuzzy-logic based on mosquito biology and climate change analysis provides new insights into the regional and global spreading of VBDs to support disease control and policy making.

  19. Present and future projections of habitat suitability of the Asian tiger mosquito, a vector of viral pathogens, from global climate simulation

    PubMed Central

    Proestos, Y.; Christophides, G. K.; Ergüler, K.; Tanarhte, M.; Waldock, J.; Lelieveld, J.

    2015-01-01

    Climate change can influence the transmission of vector-borne diseases (VBDs) through altering the habitat suitability of insect vectors. Here we present global climate model simulations and evaluate the associated uncertainties in view of the main meteorological factors that may affect the distribution of the Asian tiger mosquito (Aedes albopictus), which can transmit pathogens that cause chikungunya, dengue fever, yellow fever and various encephalitides. Using a general circulation model at 50 km horizontal resolution to simulate mosquito survival variables including temperature, precipitation and relative humidity, we present both global and regional projections of the habitat suitability up to the middle of the twenty-first century. The model resolution of 50 km allows evaluation against previous projections for Europe and provides a basis for comparative analyses with other regions. Model uncertainties and performance are addressed in light of the recent CMIP5 ensemble climate model simulations for the RCP8.5 concentration pathway and using meteorological re-analysis data (ERA-Interim/ECMWF) for the recent past. Uncertainty ranges associated with the thresholds of meteorological variables that may affect the distribution of Ae. albopictus are diagnosed using fuzzy-logic methodology, notably to assess the influence of selected meteorological criteria and combinations of criteria that influence mosquito habitat suitability. From the climate projections for 2050, and adopting a habitat suitability index larger than 70%, we estimate that approximately 2.4 billion individuals in a land area of nearly 20 million km2 will potentially be exposed to Ae. albopictus. The synthesis of fuzzy-logic based on mosquito biology and climate change analysis provides new insights into the regional and global spreading of VBDs to support disease control and policy making. PMID:25688015

  20. Present and future projections of habitat suitability of the Asian tiger mosquito, a vector of viral pathogens, from global climate simulation.

    PubMed

    Proestos, Y; Christophides, G K; Ergüler, K; Tanarhte, M; Waldock, J; Lelieveld, J

    2015-04-05

    Climate change can influence the transmission of vector-borne diseases (VBDs) through altering the habitat suitability of insect vectors. Here we present global climate model simulations and evaluate the associated uncertainties in view of the main meteorological factors that may affect the distribution of the Asian tiger mosquito (Aedes albopictus), which can transmit pathogens that cause chikungunya, dengue fever, yellow fever and various encephalitides. Using a general circulation model at 50 km horizontal resolution to simulate mosquito survival variables including temperature, precipitation and relative humidity, we present both global and regional projections of the habitat suitability up to the middle of the twenty-first century. The model resolution of 50 km allows evaluation against previous projections for Europe and provides a basis for comparative analyses with other regions. Model uncertainties and performance are addressed in light of the recent CMIP5 ensemble climate model simulations for the RCP8.5 concentration pathway and using meteorological re-analysis data (ERA-Interim/ECMWF) for the recent past. Uncertainty ranges associated with the thresholds of meteorological variables that may affect the distribution of Ae. albopictus are diagnosed using fuzzy-logic methodology, notably to assess the influence of selected meteorological criteria and combinations of criteria that influence mosquito habitat suitability. From the climate projections for 2050, and adopting a habitat suitability index larger than 70%, we estimate that approximately 2.4 billion individuals in a land area of nearly 20 million km(2) will potentially be exposed to Ae. albopictus. The synthesis of fuzzy-logic based on mosquito biology and climate change analysis provides new insights into the regional and global spreading of VBDs to support disease control and policy making.

  1. Quantifying Antimicrobial Resistance at Veal Calf Farms

    PubMed Central

    Bosman, Angela B.; Wagenaar, Jaap; Stegeman, Arjan; Vernooij, Hans; Mevius, Dik

    2012-01-01

    This study was performed to determine a sampling strategy to quantify the prevalence of antimicrobial resistance on veal calf farms, based on the variation in antimicrobial resistance within and between calves on five farms. Faecal samples from 50 healthy calves (10 calves/farm) were collected. From each individual sample and one pooled faecal sample per farm, 90 selected Escherichia coli isolates were tested for their resistance against 25 mg/L amoxicillin, 25 mg/L tetracycline, 0.5 mg/L cefotaxime, 0.125 mg/L ciprofloxacin and 8/152 mg/L trimethoprim/sulfamethoxazole (tmp/s) by replica plating. From each faecal sample another 10 selected E. coli isolates were tested for their resistance by broth microdilution as a reference. Logistic regression analysis was performed to compare the odds of testing an isolate resistant between both test methods (replica plating vs. broth microdilution) and to evaluate the effect of pooling faecal samples. Bootstrap analysis was used to investigate the precision of the estimated prevalence of resistance to each antimicrobial obtained by several simulated sampling strategies. Replica plating showed similar odds of E. coli isolates tested resistant compared to broth microdilution, except for ciprofloxacin (OR 0.29, p≤0.05). Pooled samples showed in general lower odds of an isolate being resistant compared to individual samples, although these differences were not significant. Bootstrap analysis showed that within each antimicrobial the various compositions of a pooled sample provided consistent estimates for the mean proportion of resistant isolates. Sampling strategies should be based on the variation in resistance among isolates within faecal samples and between faecal samples, which may vary by antimicrobial. In our study, the optimal sampling strategy from the perspective of precision of the estimated levels of resistance and practicality consists of a pooled faecal sample from 20 individual animals, of which 90 isolates are

  2. Transient stability enhancement of wind farms using power electronics and facts controllers

    NASA Astrophysics Data System (ADS)

    Mohammadpour, Hossein Ali

    network, and the frequency of the exchanged energy is below the fundamental frequency of the system. This phenomenon may cause severe damage in the wind farm, if not prevented. Therefore, this dissertation deals with the SSR phenomena in a capacitive series compensated wind farm. A DFIG-based wind farm, which is connected to a series compensated transmission line, is considered as a case study. The small-signal stability analysis of the system is presented, and the eigenvalues of the system are obtained. Using both modal analysis and time-domain simulation, it is shown that the system is potentially unstable due to the SSR mode. Then, three different possibilities for the addition of SSR damping controller (SSRDC) are investigated. The SSRDC can be added to (1) gate-controlled series capacitor (GCSC), (2) thyristor-controlled series capacitor (TCSC), or (3) DFIG rotor-side converter (RSC) and grid-side converter (GSC) controllers. The first and second cases are related to the series flexible AC transmission systems (FACTS) family, and the third case uses the DFIG back-to-back converters to damp the SSR. The SSRDC is designed using residue-based analysis and root locus diagrams. Using residue-based analysis, the optimal input control signal (ICS) to the SSRDC is identified that can damp the SSR mode without destabilizing other modes, and using root-locus analysis, the required gain for the SSRDC is determined. Moreover, two methods are discussed in order to estimate the optimum input signal to the SSRDC, without measuring it directly. In this dissertation, MATLAB/Simulink is used as a tool for modeling and design of the SSRDC, and PSCAD/EMTDC is used to perform time-domain simulation in order to verify the design process.

  3. Algae Farming in Low Earth Orbit: Past Present and Future

    NASA Astrophysics Data System (ADS)

    Morrison, N.

    Algal strains used as a production engine represent a novel example of living mechanical systems with tremendous potential for applications in space. Algae use photosynthesis to create lipids, glycerin, and biomass, with different strains of algae producing different oils. Algae can be grown to produce many types of oils, with low, medium or long hydrocarbon chain lengths. This article examines the history of algae research, as well as its value to astronauts as both a food supplement and as an oxygen production and carbon sequester engine. Consideration is given to ways algae is currently being used and tested in space, followed by a look forward envisioning dynamic living technological systems that can help to sustain our race as we travel the void between stars.

  4. Regional variability of the frequency distribution of daily precipitation and the synoptic characteristics of heavy precipitation events in present and future climate simulations

    NASA Astrophysics Data System (ADS)

    DeAngelis, Anthony M.

    Changes in the characteristics of daily precipitation in response to global warming may have serious impacts on human life and property. An analysis of precipitation in climate models is performed to evaluate how well the models simulate the present climate and how precipitation may change in the future. Models participating in phase 3 and 5 of the Coupled Model Intercomparison Project (CMIP3 and CMIP5) have substantial biases in their simulation of heavy precipitation intensity over parts of North America during the 20th century. Despite these biases, the large-scale atmospheric circulation accompanying heavy precipitation is either simulated realistically or the strength of the circulation is overestimated. The biases are not related to the large-scale flow in a simple way, pointing toward the importance of other model deficiencies, such as coarse horizontal resolution and convective parameterizations, for the accurate simulation of intense precipitation. Although the models may not sufficiently simulate the intensity of precipitation, their realistic portrayal of the large-scale circulation suggests that projections of future precipitation may be reliable. In the CMIP5 ensemble, the distribution of daily precipitation is projected to undergo substantial changes in response to future atmospheric warming. The regional distribution of these changes was investigated, revealing that dry days and days with heavy-extreme precipitation are projected to increase at the expense of light-moderate precipitation over much of the middle and low latitudes. Such projections have serious implications for future impacts from flood and drought events. In other places, changes in the daily precipitation distribution are characterized by a shift toward either wetter or drier conditions in the future, with heavy-extreme precipitation projected to increase in all but the driest subtropical subsidence regions. Further analysis shows that increases in heavy precipitation in midlatitudes

  5. Prospects for generating electricity by large onshore and offshore wind farms

    NASA Astrophysics Data System (ADS)

    Volker, Patrick J. H.; Hahmann, Andrea N.; Badger, Jake; Jørgensen, Hans E.

    2017-03-01

    The decarbonisation of energy sources requires additional investments in renewable technologies, including the installation of onshore and offshore wind farms. For wind energy to remain competitive, wind farms must continue to provide low-cost power even when covering larger areas. Inside very large wind farms, winds can decrease considerably from their free-stream values to a point where an equilibrium wind speed is reached. The magnitude of this equilibrium wind speed is primarily dependent on the balance between turbine drag force and the downward momentum influx from above the wind farm. We have simulated for neutral atmospheric conditions, the wind speed field inside different wind farms that range from small (25 km2) to very large (105 km2) in three regions with distinct wind speed and roughness conditions. Our results show that the power density of very large wind farms depends on the local free-stream wind speed, the surface characteristics, and the turbine density. In onshore regions with moderate winds the power density of very large wind farms reaches 1 W m‑2, whereas in offshore regions with very strong winds it exceeds 3 W m‑2. Despite a relatively low power density, onshore regions with moderate winds offer potential locations for very large wind farms. In offshore regions, clusters of smaller wind farms are generally preferable; under very strong winds also very large offshore wind farms become efficient.

  6. A hybrid wind farm parameterization for mesoscale and climate models

    NASA Astrophysics Data System (ADS)

    Pan, Y.; Archer, C. L.

    2016-12-01

    To better understand the potential impacts of wind farms on weather and climate at the local to regional scale, a new hybrid wind farm parameterization is proposed here for mesoscale models, such as the Weather Research and Forecasting Model (WRF), or climate models, such as the Community Atmosphere Model (CAM). All previous wind farm parameterizations treat all the wind turbines in the same grid cell as identical (i.e., they all share the same upstream wind velocity) and ignore the effect of wind direction. By contrast, the new hybrid model considers each individual wind turbine, based on its position in the layout and on wind direction. The new parameterization is developed starting from large eddy simulations (LES) of existing wind farms, in which the local flow around each wind turbine is directly simulated at high spatial ( 3.5 m) and temporal ( 0.1 s) resolutions and the effects of subgrid-scale processes are modeled. Based on analytic and statistical relationships between the LES results and several geometric properties of the wind farm layout (such as blockage ratio and blocking distance), the new hybrid parameterization predicts the local upstream wind speed of each individual wind turbine in the same grid cell, and thus successfully account for the effects of layout and wind direction with little computational cost. With the newly predicted upstream velocity, the turbine-induced forces and added turbulence kinetic energy (TKE) in the atmosphere are derived analytically. The wind speed, wind speed deficit, and TKE profiles and power production obtained with the hybrid parameterization for the test case (the 48-turbine Lillgrund wind farm in Sweden) are in better agreement with the LES results than previous parameterizations. Future work includes the insertion of the hybrid parameterization into the WRF code to assess impacts on near-surface properties, such as temperature and heat and momentum fluxes, in the region surrounding the wind farm.

  7. Impact of increasing milk production on whole farm environmental management

    USDA-ARS?s Scientific Manuscript database

    Increasing herd milk production can provide both economic benefit to the producer and environmental benefit to society. Simulated dairy farms with average annual herd productions from 16,000 to 30,000 lb/cow illustrate that increasing milk yield per cow improves feed efficiency, reduces feed costs a...

  8. Mesoscale to microscale wind farm flow modeling and evaluation: Mesoscale to Microscale Wind Farm Models

    SciTech Connect

    Sanz Rodrigo, Javier; Chávez Arroyo, Roberto Aurelio; Moriarty, Patrick; Churchfield, Matthew; Kosović, Branko; Réthoré, Pierre-Elouan; Hansen, Kurt Schaldemose; Hahmann, Andrea; Mirocha, Jeffrey D.; Rife, Daran

    2016-08-31

    The increasing size of wind turbines, with rotors already spanning more than 150 m diameter and hub heights above 100 m, requires proper modeling of the atmospheric boundary layer (ABL) from the surface to the free atmosphere. Furthermore, large wind farm arrays create their own boundary layer structure with unique physics. This poses significant challenges to traditional wind engineering models that rely on surface-layer theories and engineering wind farm models to simulate the flow in and around wind farms. However, adopting an ABL approach offers the opportunity to better integrate wind farm design tools and meteorological models. The challenge is how to build the bridge between atmospheric and wind engineering model communities and how to establish a comprehensive evaluation process that identifies relevant physical phenomena for wind energy applications with modeling and experimental requirements. A framework for model verification, validation, and uncertainty quantification is established to guide this process by a systematic evaluation of the modeling system at increasing levels of complexity. In terms of atmospheric physics, 'building the bridge' means developing models for the so-called 'terra incognita,' a term used to designate the turbulent scales that transition from mesoscale to microscale. This range of scales within atmospheric research deals with the transition from parameterized to resolved turbulence and the improvement of surface boundary-layer parameterizations. The coupling of meteorological and wind engineering flow models and the definition of a formal model evaluation methodology, is a strong area of research for the next generation of wind conditions assessment and wind farm and wind turbine design tools. Some fundamental challenges are identified in order to guide future research in this area.

  9. The relation between input-output transformation and gastrointestinal nematode infections on dairy farms.

    PubMed

    van der Voort, M; Van Meensel, J; Lauwers, L; Van Huylenbroeck, G; Charlier, J

    2016-02-01

    Efficiency analysis is used for assessing links between technical efficiency (TE) of livestock farms and animal diseases. However, previous studies often do not make the link with the allocation of inputs and mainly present average effects that ignore the often huge differences among farms. In this paper, we studied the relationship between exposure to gastrointestinal (GI) nematode infections, the TE and the input allocation on dairy farms. Although the traditional cost allocative efficiency (CAE) indicator adequately measures how a given input allocation differs from the cost-minimising input allocation, they do not represent the unique input allocation of farms. Similar CAE scores may be obtained for farms with different input allocations. Therefore, we propose an adjusted allocative efficiency index (AAEI) to measure the unique input allocation of farms. Combining this AAEI with the TE score allows determining the unique input-output position of each farm. The method is illustrated by estimating efficiency scores using data envelopment analysis (DEA) on a sample of 152 dairy farms in Flanders for which both accountancy and parasitic monitoring data were available. Three groups of farms with a different input-output position can be distinguished based on cluster analysis: (1) technically inefficient farms, with a relatively low use of concentrates per 100 l milk and a high exposure to infection, (2) farms with an intermediate TE, relatively high use of concentrates per 100 l milk and a low exposure to infection, (3) farms with the highest TE, relatively low roughage use per 100 l milk and a relatively high exposure to infection. Correlation analysis indicates for each group how the level of exposure to GI nematodes is associated or not with improved economic performance. The results suggest that improving both the economic performance and exposure to infection seems only of interest for highly TE farms. The findings indicate that current farm recommendations

  10. Economic efficiency analysis of different strategies to control post-weaning multi-systemic wasting syndrome and porcine circovirus type 2 subclinical infection in 3-weekly batch system farms.

    PubMed

    Alarcon, Pablo; Rushton, Jonathan; Nathues, Heiko; Wieland, Barbara

    2013-06-01

    The study assessed the economic efficiency of different strategies for the control of post-weaning multi-systemic wasting syndrome (PMWS) and porcine circovirus type 2 subclinical infection (PCV2SI), which have a major economic impact on the pig farming industry worldwide. The control strategies investigated consisted on the combination of up to 5 different control measures. The control measures considered were: (1) PCV2 vaccination of piglets (vac); (2) ensuring age adjusted diet for growers (diets); (3) reduction of stocking density (stock); (4) improvement of biosecurity measures (bios); and (5) total depopulation and repopulation of the farm for the elimination of other major pathogens (DPRP). A model was developed to simulate 5 years production of a pig farm with a 3-weekly batch system and with 100 sows. A PMWS/PCV2SI disease and economic model, based on PMWS severity scores, was linked to the production model in order to assess disease losses. This PMWS severity scores depends on the combination post-weaning mortality, PMWS morbidity in younger pigs and proportion of PCV2 infected pigs observed on farms. The economic analysis investigated eleven different farm scenarios, depending on the number of risk factors present before the intervention. For each strategy, an investment appraisal assessed the extra costs and benefits of reducing a given PMWS severity score to the average score of a slightly affected farm. The net present value obtained for each strategy was then multiplied by the corresponding probability of success to obtain an expected value. A stochastic simulation was performed to account for uncertainty and variability. For moderately affected farms PCV2 vaccination alone was the most cost-efficient strategy, but for highly affected farms it was either PCV2 vaccination alone or in combination with biosecurity measures, with the marginal profitability between 'vac' and 'vac+bios' being small. Other strategies such as 'diets', 'vac+diets' and 'bios

  11. Economic efficiency analysis of different strategies to control post-weaning multi-systemic wasting syndrome and porcine circovirus type 2 subclinical infection in 3-weekly batch system farms

    PubMed Central

    Alarcon, Pablo; Rushton, Jonathan; Nathues, Heiko; Wieland, Barbara

    2013-01-01

    The study assessed the economic efficiency of different strategies for the control of post-weaning multi-systemic wasting syndrome (PMWS) and porcine circovirus type 2 subclinical infection (PCV2SI), which have a major economic impact on the pig farming industry worldwide. The control strategies investigated consisted on the combination of up to 5 different control measures. The control measures considered were: (1) PCV2 vaccination of piglets (vac); (2) ensuring age adjusted diet for growers (diets); (3) reduction of stocking density (stock); (4) improvement of biosecurity measures (bios); and (5) total depopulation and repopulation of the farm for the elimination of other major pathogens (DPRP). A model was developed to simulate 5 years production of a pig farm with a 3-weekly batch system and with 100 sows. A PMWS/PCV2SI disease and economic model, based on PMWS severity scores, was linked to the production model in order to assess disease losses. This PMWS severity scores depends on the combination post-weaning mortality, PMWS morbidity in younger pigs and proportion of PCV2 infected pigs observed on farms. The economic analysis investigated eleven different farm scenarios, depending on the number of risk factors present before the intervention. For each strategy, an investment appraisal assessed the extra costs and benefits of reducing a given PMWS severity score to the average score of a slightly affected farm. The net present value obtained for each strategy was then multiplied by the corresponding probability of success to obtain an expected value. A stochastic simulation was performed to account for uncertainty and variability. For moderately affected farms PCV2 vaccination alone was the most cost-efficient strategy, but for highly affected farms it was either PCV2 vaccination alone or in combination with biosecurity measures, with the marginal profitability between ‘vac’ and ‘vac + bios’ being small. Other strategies such as ‘diets’,

  12. Vadose zone characterization project at the Hanford Tank Farms: U Tank Farm Report

    SciTech Connect

    1997-05-01

    The U.S. Department of Energy Grand Junction Office (DOE-GJO) was tasked by the DOE Richland Operations Office (DOE-RL) to perform a baseline characterization of the gamma-ray-emitting radionuclides that are distributed in the vadose zone sediments beneath and around the single-shell tanks (SSTs) at the Hanford Site. The intent of this characterization is to determine the nature and extent of the contamination, to identify contamination sources when possible, and to develop a baseline of the contamination distribution that will permit future data comparisons. This characterization work also allows an initial assessment of the impacts of the vadose zone contamination as required by the Resource Conservation and Recovery Act (RCRA). This characterization project involves acquiring information regarding vadose zone contamination with borehole geophysical logging methods and documenting that information in a series of reports. This information is presently limited to detection of gamma-emitting radionuclides from both natural and man-made sources. Data from boreholes surrounding each tank are compiled into individual Tank Summary Data Reports. The data from each tank in a tank farm are then compiled and summarized in a Tank Farm Report. This document is the Tank Farm Report for the U Tank Farm. Logging operations used high-purity germanium detection systems to acquire laboratory-quality assays of the gamma-emitting radionuclides in the sediments around and below the tanks. These assays were acquired in 59 boreholes that surround the U Tank Farm tanks. Logging of all boreholes was completed in December 1995, and the last Tank Summary Data Report for the U Tank Farm was issued in September 1996.

  13. CDF II production farm project

    SciTech Connect

    Baranovski, A.; Benjamin, D.; Cooper, G.; Farrington, S.; Genser, K.; Hou, S.; Hsieh, T.; Kotwal, A.; Lipeles, E.; Murat, P.; Norman, M.; /Fermilab /Duke U. /Taiwan, Inst. Phys. /UC, San Diego /Glasgow U. /Frascati

    2006-12-01

    We describe the architecture and discuss our operational experience in running the off-line reconstruction farm of the CDFII experiment. The Linux PC-based farm performs a wide set of tasks,ranging from producing calibrations and primary event reconstruction to large scale ntuple production.The farm control software uses a standard Condor toolkit and the data handling part is based on SAM (Sequential Access via Metadata)software.During its lifetime,the CDFII experiment will integrate a large amount of data (several petabytes)and the data processing chain is one of the key components of the successful physics program of the experiment.

  14. Demonstrable farm scale ethanol plant

    SciTech Connect

    Mapel, J.R.

    1982-01-01

    The objectives were: to build and demonstrate that a farm scale alcohol plant can be built and run on renewable resources, i.e. corn as the source and corn cobs as the fuel; to show that it can be a continuous operation during the winter months when field work is at a minimum; and to demonstrate that a sufficient supply of fuel can be produced to dramatically reduce dependence on non-renewable energy. The investigators felt they had succeeded with their project. The spent spillage was fed to cattle on the farm. They feel by using corn grown on the farm, the project should continue to be profitable. 7 figures.

  15. Amplified recruitment pressure of biofouling organisms in commercial salmon farms: potential causes and implications for farm management.

    PubMed

    Bloecher, Nina; Floerl, Oliver; Sunde, Leif Magne

    2015-01-01

    The development of biofouling on finfish aquaculture farms presents challenges for the industry, but the factors underlying nuisance growths are still not well understood. Artificial settlement surfaces were used to examine two possible explanations for high rates of biofouling in Norwegian salmon farms: (1) increased propagule release during net cleaning operations, resulting in elevated recruitment rates; and (2) potential reservoir effects of farm surfaces. The presence of salmon farms was associated with consistently and substantially (up to 49-fold) elevated recruitment rates. Temporal patterns of recruitment were not driven by net cleaning. Resident populations of biofouling organisms were encountered on all submerged farm surfaces. Calculations indicate that a resident population of the hydroid Ectopleura larynx, a major biofouling species, could release between 0.3 × 10(9) and 4.7 × 10(9) larvae per farm annually. Such resident populations could form propagule reservoirs and be one explanation for the elevated recruitment pressure at salmon farms.

  16. Development of FAST.Farm: A New Multiphysics Engineering Tool for Wind Farm Design and Analysis: Preprint

    SciTech Connect

    Jonkman, Jason; Annoni, Jennifer; Hayman, Greg; Jonkman, Bonnie; Purkayastha, Avi

    2017-01-01

    This paper presents the development of FAST.Farm, a new multiphysics tool applicable to engineering problems in research and industry involving wind farm performance and cost optimization that is needed to address the current underperformance, failures, and expenses plaguing the wind industry. Achieving wind cost-of-energy targets - which requires improvements in wind farm performance and reliability, together with reduced uncertainty and expenditures - has been eluded by the complicated nature of the wind farm design problem, especially the sophisticated interaction between atmospheric phenomena and wake dynamics and array effects. FAST.Farm aims to balance the need for accurate modeling of the relevant physics for predicting power performance and loads while maintaining low computational cost to support a highly iterative and probabilistic design process and system-wide optimization. FAST.Farm makes use of FAST to model the aero-hydro-servo-elastics of distinct turbines in the wind farm, and it is based on some of the principles of the Dynamic Wake Meandering (DWM) model, but avoids many of the limitations of existing DWM implementations.

  17. Is agritourism eco-friendly? A comparison between agritourisms and other farms in Italy using farm accountancy data network dataset.

    PubMed

    Mastronardi, Luigi; Giaccio, Vincenzo; Giannelli, Agostino; Scardera, Alfonso

    2015-01-01

    This paper presents the results of research regarding the environmental performances of Italian farms with agritourism compared with farms without agritourism. In Italy, agritourism is considered an agricultural activity and can only be performed by a farmer. Moreover, Italian national legislation forces the farmer to dedicate himself mainly to traditional farming, rather than to tourism activities. For this reason, environmental performances have been highlighted by analyzing only features and production systems of the farms. By utilizing the most frequent indicators used in studies regarding sustainability, the authors show how Italian agritourisms tend to develop more environmentally friendly agricultural methods, which have a positive impact on biodiversity, landscape and natural resources. The empirical analysis is based on the Italian FADN (Farm Accountancy Data Network) dataset. The European FADN was created to represent farms' technical and economic operation in the European Union and on which it drafts the agricultural and rural policies. The dichotomous structure of the dependent variable (presence or absence of agritourism at the farm) has a propensity for an assessment method based on Binary Response Model Regression.

  18. Statistical and physical modelling of large wind farm clusters

    NASA Astrophysics Data System (ADS)

    Barthelmie, R.; Pryor, S.; Frandsen, S.

    2003-04-01

    As the first large wind farms are constructed the issue of the effect of large wind farms on local climates is being raised. The main concern currently is that, in some countries, areas in which large offshore wind farms can be constructed over the next 10 to 20 years are fairly limited due to technical and economic constraints. This means that wind farms will be built in clusters of up to 100 wind turbines but within 20 km of the nearest cluster. Theoretical considerations suggest that the effects of a wind farm on a downwind wind farm maybe more noticeable offshore than onshore where higher turbulence assists wind speed recovery. Added to this many offshore areas are dominated by stable and neutral atmospheres where wakes propagate over longer distances than on land where unstable conditions also occur for a significant fraction of the time. On the other hand the large turbulence generated by the wind farm itself may be sufficient to assist wind recovery but possibly provide a higher than expected turbulence at the neighbouring wind farm or cluster. While some progress has been made with single wake modelling offshore, these models have not been evaluated for more than 5 wakes. Hence it is difficult to evaluate the impact of large wind farms and to optimise the spacing of clusters. A new project STORPARK is underway which is using statistical and physical modelling methods to make preliminary estimates of large wind farm impacts. The work described in this paper is a combination of statistical methods using observations from offshore wind monitoring sites at Vindeby/Omø Stålgrunde and Rødsand/Gedser in Denmark to evaluate in the first instance how far the effects of land can be detected on wind speed and turbulence intensity. These results will be compared with model simulations from WAsP and the Coastal Discontinuity Model (CDM) where large wind farms are currently represented by large roughness elements in accord with models developed by Crespo, Frandsen and

  19. The Research of Computer Aided Farm Machinery Designing Method Based on Ergonomics

    NASA Astrophysics Data System (ADS)

    Gao, Xiyin; Li, Xinling; Song, Qiang; Zheng, Ying

    Along with agricultural economy development, the farm machinery product type Increases gradually, the ergonomics question is also getting more and more prominent. The widespread application of computer aided machinery design makes it possible that farm machinery design is intuitive, flexible and convenient. At present, because the developed computer aided ergonomics software has not suitable human body database, which is needed in view of farm machinery design in China, the farm machinery design have deviation in ergonomics analysis. This article puts forward that using the open database interface procedure in CATIA to establish human body database which aims at the farm machinery design, and reading the human body data to ergonomics module of CATIA can product practical application virtual body, using human posture analysis and human activity analysis module to analysis the ergonomics in farm machinery, thus computer aided farm machinery designing method based on engineering can be realized.

  20. Risk-based audit selection of dairy farms.

    PubMed

    van Asseldonk, M A P M; Velthuis, A G J

    2014-02-01

    Dairy farms are audited in the Netherlands on numerous process standards. Each farm is audited once every 2 years. Increasing demands for cost-effectiveness in farm audits can be met by introducing risk-based principles. This implies targeting subpopulations with a higher risk of poor process standards. To select farms for an audit that present higher risks, a statistical analysis was conducted to test the relationship between the outcome of farm audits and bulk milk laboratory results before the audit. The analysis comprised 28,358 farm audits and all conducted laboratory tests of bulk milk samples 12 mo before the audit. The overall outcome of each farm audit was classified as approved or rejected. Laboratory results included somatic cell count (SCC), total bacterial count (TBC), antimicrobial drug residues (ADR), level of butyric acid spores (BAB), freezing point depression (FPD), level of free fatty acids (FFA), and cleanliness of the milk (CLN). The bulk milk laboratory results were significantly related to audit outcomes. Rejected audits are likely to occur on dairy farms with higher mean levels of SCC, TBC, ADR, and BAB. Moreover, in a multivariable model, maxima for TBC, SCC, and FPD as well as standard deviations for TBC and FPD are risk factors for negative audit outcomes. The efficiency curve of a risk-based selection approach, on the basis of the derived regression results, dominated the current random selection approach. To capture 25, 50, or 75% of the population with poor process standards (i.e., audit outcome of rejected), respectively, only 8, 20, or 47% of the population had to be sampled based on a risk-based selection approach. Milk quality information can thus be used to preselect high-risk farms to be audited more frequently.

  1. Integration of hydrodynamics into a statistical model on the spread of pancreas disease (PD) in salmon farming.

    PubMed

    Viljugrein, H; Staalstrøm, A; Molvaelr, J; Urke, H A; Jansen, P A

    2009-12-22

    Pancreas disease (PD) is an emerging disease in salmon farming caused by the salmonid alphavirus (SAV). SAV is evidently spread horizontally between neighbouring salmon farms, but whether such transmission occurs by passive drift in the water current or via fomites is not known. We tested whether hydrodynamic modelling contributes to explain the spread of PD, in which case SAV is likely to spread by passive drift. We present a simple logistic regression model that accounts for the effect of PD in the neighbourhood on the probability of acquiring PD in cohorts of farmed salmonids from an area on the west coast of Norway between 2005 and 2008. For a given cohort, we calculated infection pressure (IP) based on Euclidean distance, seaway distance or estimated water contact to sites with PD, and compared the amount of variance explained in the regression model by the different variants of IP. Water contact between a discharging farm site and a receiving site was calculated by simulating particle discharge using a hydrodynamic model. IP estimated by water contact was the best predictor of PD cases and controls in the model, which performed significantly better than IP estimated by seaway distance or Euclidean distance. Since the spread of PD in the study area was best explained by modelled water velocity, we conclude that PD is likely to be spread by passive drift of SAV in the water current.

  2. Modelling of paratuberculosis spread between dairy cattle farms at a regional scale.

    PubMed

    Beaunée, Gaël; Vergu, Elisabeta; Ezanno, Pauline

    2015-09-25

    Mycobacterium avium subsp. paratuberculosis (Map) causes Johne's disease, with large economic consequences for dairy cattle producers worldwide. Map spread between farms is mainly due to animal movements. Locally, herd size and management are expected to influence infection dynamics. To provide a better understanding of Map spread between dairy cattle farms at a regional scale, we describe the first spatio-temporal model accounting simultaneously for population and infection dynamics and indirect local transmission within dairy farms, and between-farm transmission through animal trade. This model is applied to Brittany, a French region characterized by a high density of dairy cattle, based on data on animal trade, herd size and farm management (birth, death, renewal, and culling) from 2005 to 2013 for 12,857 dairy farms. In all simulated scenarios, Map infection highly persisted at the metapopulation scale. The characteristics of initially infected farms strongly impacted the regional Map spread. Network-related features of incident farms influenced their ability to contaminate disease-free farms. At the herd level, we highlighted a balanced effect of the number of animals purchased: when large, it led to a high probability of farm infection but to a low persistence. This effect was reduced when prevalence in initially infected farms increased. Implications of our findings in the current enzootic situation are that the risk of infection quickly becomes high for farms buying more than three animals per year. Even in regions with a low proportion of infected farms, Map spread will not fade out spontaneously without the use of effective control strategies.

  3. Integrated watershed- and farm-scale modeling framework for targeting critical source areas while maintaining farm economic viability.

    PubMed

    Ghebremichael, Lula T; Veith, Tamie L; Hamlett, James M

    2013-01-15

    Quantitative risk assessments of pollution and data related to the effectiveness of mitigating best management practices (BMPs) are important aspects of nonpoint source pollution control efforts, particularly those driven by specific water quality objectives and by measurable improvement goals, such as the total maximum daily load (TMDL) requirements. Targeting critical source areas (CSAs) that generate disproportionately high pollutant loads within a watershed is a crucial step in successfully controlling nonpoint source pollution. The importance of watershed simulation models in assisting with the quantitative assessments of CSAs of pollution (relative to their magnitudes and extents) and of the effectiveness of associated BMPs has been well recognized. However, due to the distinct disconnect between the hydrological scale in which these models conduct their evaluation and the farm scale at which feasible BMPs are actually selected and implemented, and due to the difficulty and uncertainty involved in transferring watershed model data to farm fields, there are limited practical applications of these tools in the current nonpoint source pollution control efforts by conservation specialists for delineating CSAs and planning targeting measures. There are also limited approaches developed that can assess impacts of CSA-targeted BMPs on farm productivity and profitability together with the assessment of water quality improvements expected from applying these measures. This study developed a modeling framework that integrates farm economics and environmental aspects (such as identification and mitigation of CSAs) through joint use of watershed- and farm-scale models in a closed feedback loop. The integration of models in a closed feedback loop provides a way for environmental changes to be evaluated with regard to the impact on the practical aspects of farm management and economics, adjusted or reformulated as necessary, and revaluated with respect to effectiveness of

  4. Farm level survey of spore-forming bacteria on four dairy farms in the Waikato region of New Zealand.

    PubMed

    Gupta, Tanushree B; Brightwell, Gale

    2017-03-03

    The aim of our study was to determine the occurrence and diversity of economically important spore-forming bacteria in New Zealand dairy farm systems. Farm dairy effluent (FDE) collected from Waikato dairy farms were tested for the presence of spore-forming bacteria, using a new culture-based methodology followed by genomic analysis. An enrichment step in which samples were inoculated in cooked meat glucose starch broth under anaerobic conditions, aided in the differential isolation of Bacillus and Clostridium species. Furthermore, the use of molecular methods such as ERIC genotyping, 16S rRNA gene sequence analysis identified different spore-forming bacteria present in FDE. C. sporogenes signature PCR gave further information on the phylogenetic relationship of the different Clostridium spp. isolated in this study. In total 19 Bacillus spp., 5 Paenibacillus spp. and 17 Clostridium spp. were isolated from farm dairy effluent. Sequence types similar to economically important food spoilage bacteria viz: C. butyricum, C. sporogenes and members of the Paenibacillus Genus were isolated from all four farms, whereas, sequence types similar to potential toxigenic, B. cereus, C. perfringens, C. butyricum, and C. botulinum were found on at least three of the farms. Sampling of farm dairy effluent provides a good indicator of farm level prevalence of bacterial load as it is used to irrigate dairy pasture in New Zealand. This study highlights the presence of various spore-forming bacteria in dairy waste water and indicates the implementation of good hygienic farm practices and dairy waste effluent management.

  5. Analysis of the global atmospheric methane budget using ECHAM-MOZ simulations for present-day, pre-industrial time and the Last Glacial Maximum

    NASA Astrophysics Data System (ADS)

    Basu, A.; Schultz, M. G.; Schröder, S.; Francois, L.; Zhang, X.; Lohmann, G.; Laepple, T.

    2014-01-01

    Atmospheric methane concentrations increased considerably from pre-industrial (PI) to present times largely due to anthropogenic emissions. However, firn and ice core records also document a notable rise of methane levels between the Last Glacial Maximum (LGM) and the pre-industrial era, the exact cause of which is not entirely clear. This study investigates these changes by analyzing the methane sources and sinks at each of these climatic periods. Wetlands are the largest natural source of methane and play a key role in determining methane budget changes in particular in the absence of anthropogenic sources. Here, a simple wetland parameterization suitable for coarse-scale climate simulations over long periods is introduced, which is derived from a high-resolution map of surface slopes together with various soil hydrology parameters from the CARAIB vegetation model. This parameterization was implemented in the chemistry general circulation model ECHAM5-MOZ and multi-year time slices were run for LGM, PI and present-day (PD) climate conditions. Global wetland emissions from our parameterization are 72 Tg yr-1 (LGM), 115 Tg yr-1 (PI), and 132 Tg yr-1 (PD). These estimates are lower than most previous studies, and we find a stronger increase of methane emissions between LGM and PI. Taking into account recent findings that suggest more stable OH concentrations than assumed in previous studies, the observed methane distributions are nevertheless well reproduced under the different climates. Hence, this is one of the first studies where a consistent model approach has been successfully applied for simulating methane concentrations over a wide range of climate conditions.

  6. Organic Farming, Gender, and the Labor Process

    ERIC Educational Resources Information Center

    Hall, Alan; Mogyorody, Veronika

    2007-01-01

    This paper seeks to explain variations in gender participation in farm production and decision-making through an analysis of organic farm types, sizes, and orientations. Based on both survey and case study data, the analysis shows that female farmers on vegetable farms and mixed livestock/cash crop farms are more likely to be involved in farm…

  7. Dairying. People on the Farm. [Revised].

    ERIC Educational Resources Information Center

    Department of Agriculture, Washington, DC. Office of Governmental and Public Affairs.

    This booklet, one in a series about life on modern farms, describes the daily lives of two dairy farm families, the Schwartzbecks and the Bealls of Maryland. Beginning with early morning milking, the booklet traces the farm families through their daily work and community activities, explaining how a modern dairy farm is run. Although this booklet…

  8. Organic Farming, Gender, and the Labor Process

    ERIC Educational Resources Information Center

    Hall, Alan; Mogyorody, Veronika

    2007-01-01

    This paper seeks to explain variations in gender participation in farm production and decision-making through an analysis of organic farm types, sizes, and orientations. Based on both survey and case study data, the analysis shows that female farmers on vegetable farms and mixed livestock/cash crop farms are more likely to be involved in farm…

  9. Black Families. People on the Farm.

    ERIC Educational Resources Information Center

    Department of Agriculture, Washington, DC. Office of Governmental and Public Affairs.

    This booklet, one in a series about life on modern farms, describes the daily life of two black farm families, the Minisees of Michigan and the Sims brothers of Arkansas. Beginning with early morning chores, the booklet describes some of the chores they do in running their diversified farms and how they got started in farming. Although the booklet…

  10. Push-pull farming systems.

    PubMed

    Pickett, John A; Woodcock, Christine M; Midega, Charles A O; Khan, Zeyaur R

    2014-04-01

    Farming systems for pest control, based on the stimulo-deterrent diversionary strategy or push-pull system, have become an important target for sustainable intensification of food production. A prominent example is push-pull developed in sub-Saharan Africa using a combination of companion plants delivering semiochemicals, as plant secondary metabolites, for smallholder farming cereal production, initially against lepidopterous stem borers. Opportunities are being developed for other regions and farming ecosystems. New semiochemical tools and delivery systems, including GM, are being incorporated to exploit further opportunities for mainstream arable farming systems. By delivering the push and pull effects as secondary metabolites, for example, (E)-4,8-dimethyl-1,3,7-nonatriene repelling pests and attracting beneficial insects, problems of high volatility and instability are overcome and compounds are produced when and where required.

  11. Farming Flexibility Act of 2009

    THOMAS, 111th Congress

    Rep. Baldwin, Tammy [D-WI-2

    2009-02-03

    House - 04/23/2009 Referred to the Subcommittee on General Farm Commodities and Risk Management. (All Actions) Tracker: This bill has the status IntroducedHere are the steps for Status of Legislation:

  12. Space Farm 7 Belvedere Plantation

    NASA Image and Video Library

    A space theme maze and NASA exhibits turned a Virginia farm into an out-of-this-world experience for families and visitors at the Belvedere Plantation in Fredericksburg, Virginia. Belvedere Plantat...

  13. Farm Protection Act of 2014

    THOMAS, 113th Congress

    Rep. Crawford, Eric A. "Rick" [R-AR-1

    2014-09-18

    House - 09/30/2014 Referred to the Subcommittee on General Farm Commodities and Risk Management. (All Actions) Tracker: This bill has the status IntroducedHere are the steps for Status of Legislation:

  14. Electrocution Hazards on the Farm

    MedlinePlus

    ... electrical hazards posed by overhead power lines, standby generators, and general operating procedures of electrical systems at ... this gate because of the overhead line.” Standby generators Some farms are equipped with a standby generator ...

  15. Green Care Farms

    PubMed Central

    de Bruin, Simone R.; Stoop, Annerieke; Molema, Claudia C. M.; Vaandrager, Lenneke; Hop, Peter J. W. M.; Baan, Caroline A.

    2015-01-01

    Objective: To explore the value of day services at green care farms (GCFs) in terms of social participation for people with dementia. Method: Semi-structured interviews were conducted with people with dementia who attended day services at a GCF (GCF group, n = 21), were on a waiting list (WL) for day services at a GCF (WL group, n = 12), or attended day services in a regular day care facility (RDCF group, n = 17) and with their family caregivers. Results: People with dementia in the GCF and WL group were primarily males, with an average age of 71 and 76 years, respectively, who almost all had a spousal caregiver. People with dementia in the RDCF group were mostly females with an average age of 85 years, most of whom had a non-spousal caregiver. For both the GCF and RDCF groups, it was indicated that day services made people with dementia feel part of society. The most important domains of social participation addressed by RDCFs were social interactions and recreational activities. GCFs additionally addressed the domains “paid employment” and “volunteer work.” Conclusion: GCFs are valuable in terms of social participation for a particular group of people with dementia. Matching characteristics of adult day services (ADS) centers to the preferences and capacities of people with dementia is of importance. Diversity in ADS centers is therefore desirable. PMID:28138469

  16. Exploring the wakes of large offshore wind farms

    NASA Astrophysics Data System (ADS)

    Emeis, S.; Siedersleben, S.; Lampert, A.; Platis, A.; Bange, J.; Djath, B.; Schulz-Stellenfleth, J.; Neumann, T.

    2016-09-01

    Offshore meteorological characteristics set specific conditions for the operation of offshore wind farms. One specific feature is low turbulence intensity which on the one hand reduces loads on turbines but on the other hand is the reason for much longer turbine and farm wakes than over land. The German Government is presently funding a research project called WIPAFF (Wind PArk Far Field) which heads for the analysis of properties and impacts of offshore wind park far fields. The focus is on the analysis of wind farm wakes, their interaction among each other and their regional climate impact. This is done by in-situ, extensive aircraft and satellite measurements and by operating meso-scale wind field models and an analytical wind farm model.

  17. Evaluation of 241 AN tank farm flammable gas behavior

    SciTech Connect

    Reynolds, D.A.

    1994-01-01

    The 241 AN Tank Farm tanks 241-AN-103, -104, and 105 are Flammable Gas Watch List tanks. Characteristics exhibited by these tanks (i.e., surface level drops, pressure increases, and temperature profiles) are similar to those exhibited by tank 241-SY-101, which is also a Watch List tank. Although the characteristics exhibited by tank 241-SY-101 are also present in tanks 241-AN-103, -104, and 105, they are exhibited to a lesser degree in the AN Tank Farm tanks. The 241 AN Tank Farm tanks have only small surface level drops, and the pressure changes that occur are not sufficient to release an amount of gas that would cause the dome space to exceed the lower flammability limit (LFL) for hydrogen. Therefore, additional restrictions are probably unnecessary for working within the 241 AN Tank Farm, either within the dome space of the tanks or in the waste.

  18. ICPP Tank Farm systems analysis

    SciTech Connect

    Palmer, W.B.; Beer, M.J.; Cukars, M.; Law, J.P.; Millet, C.B.; Murphy, J.A.; Nenni, J.A.; Park, C.V.; Pruitt, J.I.; Thiel, E.C.; Ward, F.S.; Woodard, J.

    1994-01-01

    During the early years (1950--1965) of Idaho Chemical Processing Plant (ICPP) operations, eleven, 300,000-gallon waste storage tanks were constructed. A project was in progress to replace these aging tanks; however, since fuel reprocessing has been curtailed at ICPP, it is not clear that the new tanks are required. The Department of Energy (DOE) requested a systems engineering evaluation to determine the need for the new tanks. Over 100 alternatives were identified during a facilitated team meeting using Value Engineering techniques. After eliminating any ideas which clearly could not meet the requirements, the remaining ideas were combined into nine basic cases with five sub cases. These fourteen cases were then carefully defined using two methods. First, each case was drawn graphically to show waste processing equipment interfaces and time constraints where they existed or were imposed. Second, each case was analyzed using a time-dependent computer simulation of ICPP waste management activities to determine schedule interactions, liquid storage requirements, and solid waste quantities. Based on the evaluation data, the team developed the following recommendations: Install and operate the high-level liquid waste evaporator; minimize liquid waste generation as much as possible within the constraints of required ICPP operational, safety, and environmental commitments; bring a Waste Immobilization Facility on line by 2008 or earlier; operate NWCF as required to alleviate the need for new tank farm capacity; maximize the concentration of Na and K in the calcine to minimize the final amount of waste requiring immobilization; avoid using Bin Set 7 for calcine storage, if possible, to reduce future calcine retrieval and D&D costs; and use WM-190 for liquid waste storage and one of the pillar and panel vaulted tanks as the spare.

  19. Off-Farm Labour Decision of Canadian Farm Operators: Urbanization Effects and Rural Labour Market Linkages

    ERIC Educational Resources Information Center

    Alasia, Alessandro; Weersink, Alfons; Bollman, Ray D.; Cranfield, John

    2009-01-01

    Understanding the factors affecting off-farm labour decisions of census-farm operators has significant implications for rural development and farm income support policy. We examine the off-farm labour decisions of Canadian farm operators using micro-level data from the 2001 Census of Agriculture combined with community level data from the 2001…

  20. 29 CFR 780.141 - Practices must relate to farming operations on the particular farm.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 29 Labor 3 2010-07-01 2010-07-01 false Practices must relate to farming operations on the... UNDER THE FAIR LABOR STANDARDS ACT General Scope of Agriculture âsuch Farming Operationsâ-on the Farm § 780.141 Practices must relate to farming operations on the particular farm. “Practices * * *...