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. Transgenic farm animals: present and future.

    PubMed

    Niemann, H; Kues, W; Carnwath, J W

    2005-04-01

    Until recently, pronuclear microinjection of deoxyribonucleic acid (DNA) was the standard method for producing transgenic animals. This technique is now being replaced by more efficient protocols based on somatic nucleartransferthat also permit targeted genetic modifications. Lentiviral vectors and small interfering ribonucleic acid technology are also becoming important tools for transgenesis. Transgenic farm animals are important in human medicine as sources of biologically active proteins, as donors in xenotransplantation, and for research in cell and gene therapy. Typical agricultural applications include improved carcass composition, lactational performance and wool production, as well as enhanced disease resistance and reduced environmental impact. Product safety can be ensured by standardisation of procedures and monitored by polymerase chain reaction and array technology. As sequence information and genomic maps of farm animals are refined, it becomes increasingly practical to remove or modify individual genes. This approach to animal breeding will be instrumental in meeting global challenges in agricultural production in the future. PMID:16110896

  3. Whole-farm simulation to determine effective conservation practices

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Because management decisions are made at the farm level, effective conservation practices must be both efficient in controlling air- and water-borne farm emissions and feasible with regard to farm production and profit. The Integrated Farm Systems Model (IFSM) provides a process-based simulation of ...

  4. Simulating Methane Emissions from Dairy Farms

    Technology Transfer Automated Retrieval System (TEKTRAN)

    As a sector, agriculture is reported to be the third greatest contributor of methane (CH4) in the U.S., emitting one-quarter of total emissions. The primary sources of CH4 on a dairy farm are the animals and manure storage, with smaller contributions from field-applied manure, feces deposited by gra...

  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. 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.

  7. 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. PMID:20572873

  8. 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.

  9. 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.

  10. 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.

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

    Technology Transfer Automated Retrieval System (TEKTRAN)

    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...

  12. 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

  13. 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. PMID:25950016

  14. Present Status of GNF New Nodal Simulator

    SciTech Connect

    Iwamoto, T.; Tamitani, M.; Moore, B.

    2001-06-17

    This paper presents core simulator consolidation work done at Global Nuclear Fuel (GNF). The unified simulator needs to supercede the capabilities of past simulator packages from the original GNF partners: GE, Hitachi, and Toshiba. At the same time, an effort is being made to produce a simulation package that will be a state-of-the-art analysis tool when released, in terms of the physics solution methodology and functionality. The core simulator will be capable and qualified for (a) high-energy cycles in the U.S. markets, (b) mixed-oxide (MOX) introduction in Japan, and (c) high-power density plants in Europe, etc. The unification of the lattice physics code is also in progress based on a transport model with collision probability methods. The AETNA core simulator is built upon the PANAC11 software base. The goal is to essentially replace the 1.5-energy-group model with a higher-order multigroup nonlinear nodal solution capable of the required modeling fidelity, while keeping highly automated library generation as well as functionality. All required interfaces to PANAC11 will be preserved, which minimizes the impact on users and process automation. Preliminary results show statistical accuracy improvement over the 1.5-group model.

  15. Large eddy simulations of vertical axis wind turbines to optimize farm design

    NASA Astrophysics Data System (ADS)

    Hezaveh, Seyed Hossein; Bou-Zeid, Elie

    2013-11-01

    Wind energy production, and research have expanded considerably in the past decade. These efforts aim to reduce dependence on fossil fuels and the greenhouse gas emissions associated with current modes of energy production. However, with expanding wind farms, the land areas occupied by such farms become a limitation. Recently, interest in vertical axis wind turbines (VAWTs) has increased due to key advantages of this technology: compared to horizontal axis turbines, VAWTs can be built with larger scales, their performance is not sensitive to wind direction, and the ability to place their generators at the bottom of the mast can make them more stable offshore. In this study, we focus on how the Aspheric Boundary Layer (ABL) will react to the presence of large VAWT farms. We present a state-of-art representation of VAWTs using an actuator line model in a Large Eddy Simulations code for the ABL. Validations are made against several experimental datasets, which include flow details and power coefficient curves, the wake of an individual turbine is visualized and analyzed, and the interaction of adjacent turbines is investigated in view of optimizing their interactions and the configuration of VAWT farms.

  16. Simulation in neurosurgery: Past, present, and future.

    PubMed

    Suri, Ashish; Patra, Devi Prasad; Meena, Rajesh Kumar

    2016-01-01

    Neurosurgery is one of the most technically demanding medical professions that warrants a high level of expertise. In the present context of competitive medical practice, high societal expectations regarding quality of patient care and medicolegal and financial constraints, there are fewer opportunities for a trainee to achieve competency in standard neurosurgical, microsurgical, and operative techniques. Practice on simulation models like cadavers has been a trend since antiquity; however, recent development of newer models with their strategic modifications has given simulation education a new dimension. It has allowed trainees to acquire and improve surgical skills and knowledge in specifically fabricated and controlled settings with no risk to real patients. Simulation also offers the opportunity for deliberate practice and repetition unlimited number of times so that psychomotor skills can be automated. There is ever-growing evidence showing the positive impact of simulation on resident training in various areas of health care. Advances in computer technology and imaging, development of sophisticated virtual reality simulators with haptic feedback and the recent addition of three-dimensional printing technology, have opened a wide arena for the development of high-fidelity patient-specific models to complement current neurosurgical training. Simulation training in neurosurgery in India is still elementary since its inception at the All India Institute of Medical Sciences, New Delhi. A structured modular training program has been developed which is yet to be implemented at a multi-institutional level. Stringent efforts are needed to establish a uniform resident training curriculum where simulators can be used to complement current neurosurgical training. PMID:27147144

  17. 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

  18. 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.

  19. 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.

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

    Technology Transfer Automated Retrieval System (TEKTRAN)

    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...

  1. 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.

  2. NUMERICAL SIMULATION OF POLLUTANT TRANSPORT FROM FISH FARMING IN RIVER

    NASA Astrophysics Data System (ADS)

    Tran Thi Ngoc, Trieu; Le Song, Giang; Lu, Minjiao

    This paper presented a 3D model for substance transport in river and its application for simulation of pollutant transport in Mekong river due to floating cages-raising. 3D flow-field was solved by logarithmic distributing 2D flow-field of averaged height. Pollutant transport is calculated by solving its full 3D transport equation. The 2D continuum and momentum equations were solved by finite difference method with ADI scheme of Ponce-Yabusaki. The 3D transport equation was solved by finite volume method with ADI scheme of Douglas-Gunn in "sigma" transformed co-ordinate. The model was tested over analytical solution. Some preliminary results of simulation for pollutant transport of Myhoahung floating cages area (Angiang province) are also presented.

  3. 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

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

    PubMed

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

    2014-04-01

    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

  5. 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.

  6. 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.

  7. 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.

  8. 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).

  9. Evaluation of a British computer model to simulate gastrointestinal nematodes in sheep on Canadian farms.

    PubMed

    Guthrie, A D; Learmount, J; VanLeeuwen, J; Peregrine, A S; Kelton, D; Menzies, P I; Fernández, S; Martin, R C; Mederos, A; Taylor, M A

    2010-11-24

    With increasing levels of anthelmintic resistance worldwide and a growing demand to produce more organic products, utilisation of control strategies for gastrointestinal nematodes (GIN) that minimize the use of anthelmintics becomes even more important. This study evaluated the farm-level performance of an existing predictive sheep parasite model from the United Kingdom (UK), using Canadian data. The UK model simulates the epidemiology of three major GIN species of interest (Teladorsagia spp., Haemonchus spp. and Trichostrongylus spp.) and provides a prediction about seasonal parasite levels of lambs and ewes. Model inputs were generated by using data from the first 2 years of a 3-year study (2006-2008) which examined the epidemiology of GIN parasitism in Ontario sheep flocks. Required input data included ewe parasite egg output, pasture-related information and management dynamics. Farm visits in 2006 and 2007 provided relevant data that were collected monthly during the grazing season, on six and seven occasions respectively. These data were collected from 10 ewes and 10 lambs on each farm. For 23 Ontario farms with available data, only 11 farms in 2006 and 14 in 2007 had suitable data to run in the model because the Canadian study was not specifically designed with this simulation model in mind. Observed values for faecal egg counts (FEC) were compared to the model FEC outputs and assessed using linear regression analysis. There was adequate fit between observed and simulated data for 8 of the 11 farms modelled using data generated in 2006 (F=7.55-42.66, df=10-11, R(2)=0.43-0.81, p=0.021 to <0.001) and with 8 of the farms modelled using data generated in 2007 (F=5.56-35.82, df=9-11, R(2)=0.36-0.82, p=0.040 to <0.001). We suggest that the poor fit between observed and simulated data for some data sets may be attributable to low-level infection on farms making regression difficult due to insensitivity of the egg count method at low values, or a pattern for immunity

  10. 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.

  11. 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.

  12. 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

  13. 2004 Initial Assessments of Closure for the S-SX Tank Farm: Numerical Simulations

    SciTech Connect

    Zhang, Z F; Freedman, Vicky L; Waichler, Scott R; White, Mark D

    2004-04-01

    In support of CH2M HILL Hanford Group, Inc.'s (CHG) preparation of a Field Investigative Report (FIR) for the closure of the Hanford Site Single-Shell Tank (SST) Waste Management Area (WMA) tank farms, a set of numerical simulations of flow and solute transport was executed to investigate different potential contaminant source scenarios that may pose long-term risks to groundwater from the closure of the S-SX Tank Farm. This report documents the simulation of 7 cases (plus two verification) involving two-dimensional cross sections through the S Tank Farm (Tanks S-101, S102, and S-103) and the simulation of one case involving three-dimensional domain of the S Tank Farm. Using a unit release scenario at Tank S-103, three different types of leaks were simulated. These simulations assessed the effect of leaks during retrieval as well as residual wastes and ancillary equipment after closure. Two transported solutes were considered: uranium-238 (U-238) and technetium-99 (Tc 99). To evaluate the effect of sorption on contaminant transport, six different sorption coefficients were simulated for U 238. Overall, simulations results for the S Tank Farm showed that only a small fraction (< 0.4%) of the U-238 with sorption coefficients 0.6 mL/g migrated from the vadose zone in all of the cases. For the conservative solute, Tc-99, results showed that the simulations investigating leaks during retrieval demonstrated the highest peak concentrations and the earliest arrival times due to the high infiltration rate before water was added and surface barriers installed. Residual leaks were investigated with different release rate models, including uniform release, advection-dominated, diffusion-dominated, and saltcake (solubility-controlled) release models. Of the four models, peak concentrations were lowest and arrival times later for the uniform release model due to the lower release rate of the residual tank waste solids; similar high peak concentrations occurred for the advection

  14. A stochastic simulation model for assessment of investments in Precision Dairy Farming technologies: model enhancements and utility demonstration

    Technology Transfer Automated Retrieval System (TEKTRAN)

    A previously described stochastic simulation model of a dairy enterprise was modified for improved robustness. This model was developed to evaluate investments in Precision Dairy Farming technologies and was constructed to embody the biological and economic complexities of a dairy farm system within...

  15. 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)

  16. 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

  17. 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

  18. A Farm Management Problem. Student Workbook. AGDEX 810.

    ERIC Educational Resources Information Center

    Cackler, William

    This workbook is intended for use by students taking part in a farm management simulation that has been designed to help them develop competency in both crop and livestock farming. The introductory section presents an overview of the workbook's contents. The remainder of the workbook contains rules for the farm management problem, farm layouts,…

  19. Simulation of irregular waves in an offshore wind farm with a spectral wave model

    NASA Astrophysics Data System (ADS)

    Ponce de León, S.; Bettencourt, J. H.; Kjerstad, N.

    2011-10-01

    A numerical study of irregular waves in the Norwegian continental shelf wind farm (HAVSUL-II) was conducted using 3rd generation spectral wave models. The study was composed of two parts: the study of the effect of a single windmill monopile in the local incoming wave field using an empirical JONSWAP spectrum, and a wave hindcast study in the wind farm area using realistic incoming wave spectra obtained from large scale simulations for the 1991-1992 winter period. In the single windmill monopile study the SWAN wave model was used, while the hindcast study was conducted by successively nesting from a coarse grid using the WAM model up to a high-resolution (56 m) grid covering 26.2 km 2 of the HAVSUL-II windmill farm using the SWAN model. The effect of a single monopile on incident waves with realistic spectra was also studied. In the single windmill study the monopile was represented as a closed circular obstacle and in the hindcast study it was represented as a dry grid point. The results showed that the single windmill monopile creates a shadow zone in the down wave region with lower significant wave height ( Hs) values and a slight increase of Hs in the up wave region. The effects of the windmill monopile on the wave field were found to be dependent on the directional distribution of the incoming wave spectrum and also on the wave diffraction and reflection. The hindcast study showed that the group of windmill monopiles may contribute to the reduction of the wave energy inside the offshore wind farm and that once the waves enter into the offshore wind farm they experience modifications due to the presence of the windmill monopiles, which cause a blocking of the wave energy propagation resulting in an altered distribution of the Hs field.

  20. 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. PMID:24518587

  1. 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)

  2. 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.

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

    DOE PAGESBeta

    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

  4. 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”

  5. 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.

  6. 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

  7. 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

  8. Large-eddy simulation of an infinitely large wind farm in a stable atmospheric boundary layer

    NASA Astrophysics Data System (ADS)

    Lu, H.; Porté-Agel, F.

    2010-09-01

    When deployed as large arrays, wind turbines interact among themselves and with atmospheric boundary layer. To optimize their geometric arrangements, accurate knowledge of wind-turbine array boundary layer is of great importance. In this study, we integrated large eddy simulation with an actuator line technique, and used it to study the characteristics of wind-turbine wake in an idealized wind farm inside a stably stratified atmospheric boundary layer (SBL). The wind turbines, with a rotor diameter of 112m and a tower height of 119m, were placed in a well-known SBL turbulent case that has a boundary layer height of approximately 180m. The super-geostrophic nocturnal jet near the top of the boundary layer was eliminated due to the energy extraction and the enhanced mixing of momentum. Non-axisymmetric behavior of wake structure was observed in response to the non-uniform incoming turbulence, the Coriolis effects, and the rotational effects induced by blade motions. The turbulence intensity in the simulated turbine wakes was found to reach a maximum at the top-tip level and a downwind distance of approximately 3-5 rotor diameters from the turbines. The Coriolis effects caused a skewed spatial structure and drove certain amount of turbulent energy away from the center of the wake. The SBL height was increased, while the magnitudes of the surface momentum flux and the surface buoyancy flux were reduced by approximately 30%. The wind farm was also found to have a strong effect on area-averaged vertical turbulent fluxes of momentum and heat, which highlights the potential impact of wind farms on local meteorology.

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

    Technology Transfer Automated Retrieval System (TEKTRAN)

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

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

    Technology Transfer Automated Retrieval System (TEKTRAN)

    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...

  11. 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

  12. 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

  13. 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

  14. Collective phenomena in large-eddy simulations of extended wind farms

    NASA Astrophysics Data System (ADS)

    Stevens, Richard; Meneveau, Charles

    2012-11-01

    A major issue with respect to the incorporation of large wind farms in power grids is that their power output strongly fluctuates over time. Understanding these fluctuations, especially its spatio-temporal characteristics, is important for the design of the backup power that must be available. The power fluctuations of the turbines depend on the effect of the wakes, created by a prior row of turbines, on the operation of the turbines, the inter-turbine correlations, and the interaction between the turbines and the atmospheric boundary layer (ABL). We analyze the power fluctuations in large eddy simulations of extended wind-parks in the ABL. We consider various aggregates of wind turbines such as the total average power signal, or sub-averages within the wind farm. In particular, we find that the power variations of the total wind park decreases more than one would expect if one assumes the power output of the turbines to be uncorrelated. The non-trivial correlations are due to the interactions between turbines placed down-stream from each other. Surprisingly, the frequency spectra of the total wind-farm output show a decay that follows approximately a -5/3 power-law scaling regime, qualitatively consistent with observations made in field-scale operational wind parks (Apt, 2007). RS is supported by a ``Fellowship for Young Energy Scientists'' (YES!) of the Foundation for Fundamental Research on Matter (FOM), which is supported by the Netherlands Organization for Scientific Research (NWO). CM is supported by NSF-CBET 1133800.

  15. 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.

  16. 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

  17. 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

  18. Supporting strategic thinking of smallholder dairy farmers using a whole farm simulation tool.

    PubMed

    Le Gal, Pierre-Yves; Bernard, Jennifer; Moulin, Charles-Henri

    2013-06-01

    This article investigates how a one-to-one support process based on the use of a whole dairy farm simulation tool helps both farmers to reflect on their production strategies and researchers to better understand the farmers' contexts of action and decision. The support process consists of a minimum of four discussion sessions with the farmer: designing the Initial Scenario and formulating a diagnosis, building and simulating the Project Scenario corresponding to the objective targeted by the farmer, building and comparing alternative scenarios proposed both by the farmer and the researcher, and evaluating the process with the farmer. The approach was tested with six smallholder farmers in Brazil. It is illustrated with the example of one farmer who aimed to develop his milk production by more than doubling his herd size on the same cultivated area. Two other examples illustrate the diversity of issues addressed with this approach. The first estimates the sensitivity of economic results to price variations of milk and concentrates. The second compares two scenarios in terms of forage supply autonomy. The discussion assesses the outcomes of the approach for farmers in terms of response to their specific issues and of knowledge acquired. The research outputs are discussed in terms of the value and limits of using simulation tools within both participatory action research and advisory processes. PMID:23224951

  19. 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. PMID:26994379

  20. DEVELOPMENT OF A STOCHASTIC SIMULATION MODEL TO ASSESS THE POTENTIAL ECONOMIC BENEFITS ASSOCIATED WITH INVESTMENTS IN PRECISION DAIRY FARMING TECHNOLOGIES

    Technology Transfer Automated Retrieval System (TEKTRAN)

    A dynamic, stochastic, mechanistic simulation model of a modern dairy enterprise was developed to evaluate the costs and benefits associated with investments in Precision Dairy Farming (PDF) technologies. The model was designed to represent the biological and economic complexities of a dairy system ...

  1. 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.

  2. 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.

  3. 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.

  4. 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

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

    Technology Transfer Automated Retrieval System (TEKTRAN)

    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 ...

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

    Technology Transfer Automated Retrieval System (TEKTRAN)

    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...

  7. 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

  8. 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

  9. 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.

  10. 2003 Initial Assessments of Closure for the C Tank Farm Field Investigation Report (FIR):Numerical Simulations

    SciTech Connect

    Zhang, Z. F.; Freedman, Vicky L.; White, Mark D.

    2003-07-15

    In support of CH2M HILL Hanford Group, Inc.'s (CHG) preparation of a Field Investigative Report (FIR) for the closure of the Hanford Site Single-Shell Tank (SST) Waste Management Area (WMA) tank farms, a set of numerical simulations of flow and solute transport was executed to predict the performance of surface barriers for reducing long-term risks from potential groundwater contamination at the C Farm WMA. This report documents the simulation of 14 cases (and two verification cases) involving two-dimensional cross sections through the C Farm WMA tanks C-103 – C-112. Utilizing a unit release scenario at Tank C-112, four different types of leaks were simulated. These simulations assessed the impact of leakage during retrieval, past leaks, and tank residual wastes and tank ancillary equipment following closure activities. . Two transported solutes were considered: uranium-238 (U-238) and technetium-99 (Tc-99). To evaluate the impact of sorption to the subsurface materials, six different retardation coefficients were simulated for U-238. Overall, simulations results for the C Farm WMA showed that only a small fraction of the U-238 with retardation factors greater than 0.6 migrated from the vadose zone in all of the cases. For the conservative solute, Tc-99, results showed that the simulations investigating leakages during retrieval demonstrated the highest WMA peak concentrations and the earliest arrival times due to the high infiltration rate before the use of surface barriers and the addition of water into the system. Simulations investigating past leaks showed similar peaks and arrival times as the retrieval leak cases. Several different release rates were used to investigate contaminant transport from residual tank wastes. All showed similar peak concentrations and arrival times, except for the lowest initial release rate, which was 1,000 times slower than the highest release rate. Past leaks were also investigated with different release rate models, including

  11. Large-eddy Simulation of Atmospheric Boundary-layer Flow through a Wind Farm Sited on Complex Terrain

    NASA Astrophysics Data System (ADS)

    Shamsoddin, Sina; Porté-Agel, Fernando

    2015-04-01

    In this work, the performance of a wind farm situated on a hilly terrain is studied using large-eddy simulation and especial attention is paid to the effect of the topography on the wake flow characteristics. To this end, first, boundary-layer flow is simulated over a two-dimensional hill and the corresponding mean and instantaneous flow-field is captured. Subsequently, flow simulation through a wind farm, consisting of five horizontal-axis wind turbines, sited over the same hill in an aligned layout is performed and the resulting flow characteristics are compared with the former case, i.e., the case without wind turbines. To assess the validity of the simulations, the calculated results are compared with the measurements carried out by Tian et al. (2013) in the aerodynamic/atmospheric boundary layer wind tunnel of Iowa State University. The agreement between the simulation and experimental results is good in terms of mean velocity and turbulence intensity profiles at different streamwise positions.

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

    Technology Transfer Automated Retrieval System (TEKTRAN)

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

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Recently, wet storage methods have been proposed for feedstock preservation and on-farm storage of perennial grass and corn stover biomass. The advantages over a dry storage system include lower risk of fire, reduced harvest costs, and improved feedstock susceptibility to enzymatic hydrolysis. We ...

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

    Technology Transfer Automated Retrieval System (TEKTRAN)

    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...

  15. Turbulent Inflow Precursor Method with Time-Varying Direction for Large-Eddy Simulations and Applications to Wind Farms

    NASA Astrophysics Data System (ADS)

    Munters, Wim; Meneveau, Charles; Meyers, Johan

    2016-05-01

    A major challenge in turbulence-resolving flow simulations is the generation of unsteady and coherent turbulent inflow conditions. Precursor methods have proven to be reliable inflow generators but are limited in applicability and flexibility especially when attempting to couple boundary-layer dynamics with large-scale temporal variations in the direction of the inflow. Here, we propose a methodology that is capable of providing fully developed turbulent inflow for time-varying mean-flow directions. The method is a generalization of a concurrent precursor inflow technique, in which a fully developed boundary-layer simulation that uses periodic boundary conditions is dynamically rotated with the large-scale wind direction that drives the simulation in the domain of interest. The proposed inflow method is applied to large-eddy simulations of boundary-layer flow through the Horns Rev wind farm when subjected to a sinusoidal variation in wind direction at the hourly time scale.

  16. 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.'

  17. 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.

  18. 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.

  19. SIMULATION OF METHANE EMISSIONS FROM DAIRY FARMS TO ASSESS GREENHOUSE GAS REDUCTION STRATEGIES

    Technology Transfer Automated Retrieval System (TEKTRAN)

    As a sector, agriculture is reported to be the third greatest contributor to atmospheric methane (CH**4) in the U.S., emitting one-quarter of total emissions. Primary sources of CH**4 emission on dairy farms are the animals and manure storage, with smaller contributions from field-applied manure, fe...

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

    Technology Transfer Automated Retrieval System (TEKTRAN)

    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 ...

  1. 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.

  2. 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.

  3. Development of a network based model to simulate the between-farm transmission of the porcine reproductive and respiratory syndrome virus.

    PubMed

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

    2015-11-18

    Contact structure within a population can significantly affect the outcomes of infectious disease spread models. The objective of this study was to develop a network based simulation model for the between-farm spread of porcine reproductive and respiratory syndrome virus to assess the impact of contact structure on between-farm transmission of PRRS virus. For these farm level models, a hypothetical population of 500 swine farms following a multistage production system was used. The contact rates between farms were based on a study analyzing movement of pigs in Canada, while disease spread parameters were extracted from published literature. Eighteen distinct scenarios were designed and simulated by varying the mode of transmission (direct versus direct and indirect contact), type of index herd (farrowing, nursery and finishing), and the presumed network structures among swine farms (random, scale-free and small-world). PRRS virus was seeded in a randomly selected farm and 500 iterations of each scenario were simulated for 52 weeks. The median epidemic size by the end of the simulated period and percentage die-out for each scenario, were the key outcomes captured. Scenarios with scale-free network models resulted in the largest epidemic sizes, while scenarios with random and small-world network models resulted in smaller and similar epidemic sizes. Similarly, stochastic die-out percentage was least for scenarios with scale-free networks followed by random and small-world networks. Findings of the study indicated that incorporating network structures among the swine farms had a considerable impact on the spread of PRRS virus, highlighting the importance of understanding and incorporating realistic contact structures when developing infectious disease spread models for similar populations. PMID:26464321

  4. 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. PMID:26780770

  5. 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. PMID:26431614

  6. 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.

  7. 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

  8. 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).

  9. 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.

  10. 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.

  11. Parameterization of wind farms in COSMO-LM

    NASA Astrophysics Data System (ADS)

    Stuetz, E.; Steinfeld, G.; Heinemann, D.; Peinke, J.

    2012-04-01

    In order to examine the impact of wind farms in the meso scale using numerical simulations parameterizations of wind farms were implemented in a mesoscale model. In 2008/2009 the first wind farm in the german exclusive economic zone - Alpha Ventus - was built. Since then more wind farms are erected in the german exclusive economic zone. Wind farms with up to 80 wind turbines and on an area up to 66 square kilometers are planned - partly only few kilometers apart from one another. Such large wind farms influence the properties of the atmospheric boundary layer at the meso scale by a reduction of the wind speed, a enhancement of the turbulent kinetic energy, but also an alternation of the wind direction. Results of models for the calculation of wakes (wake models), idealistic mesoscale studies as well as observations show, that wind farms of this size produce wakes, which can expand up to a few 10 kilometers downstream. Mesoscale models provide the possibility to investigate the impact of such large wind farms on the atmospheric flow in a larger area and also to examine the effect of wind farms under different weather conditions. For the numerical simulation the mesoscale model COSMO-LM is used. Because the wind turbines of the wind farm cannot be displayed individually due to the large mesh-grid size, the effects of the wind turbine in a numerical model have to be described with the help of a parameterization. Different parameterizations, including the interpretation of a wind farm as enhanced surface roughness or as an impuls deficit and turbulence source, respectively, are implemented into COSMO. The impact of the different wind farm parameterizations on the simulation of the atmospheric boundary layer are presented. as well as first tests of idealistic simulations of wind farms are presented. For this purpose idealistic runs as well as a case study were performed.

  12. 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.

  13. 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. PMID:24715387

  14. 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…

  15. 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,…

  16. 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

    2012-06-01

    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

  17. An Evaluation of Student Perceptions of Screen Presentations in Computer-based Laboratory Simulations.

    ERIC Educational Resources Information Center

    Edward, Norrie S.

    1997-01-01

    Evaluates the importance of realism in the screen presentation of the plant in computer-based laboratory simulations for part-time engineering students. Concludes that simulations are less effective than actual laboratories but that realism minimizes the disadvantages. The schematic approach was preferred for ease of use. (AIM)

  18. 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,…

  19. 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.

  20. The present status of "quick tests" for on-farm analysis with emphasis on manures and soil: What is available and what is lacking?

    Technology Transfer Automated Retrieval System (TEKTRAN)

    There has been an increasing interest in on-farm testing of a variety of products produced and utilized on the farm including manure and soil composition. Several issues involved include which constituents are of interest, e.g., fiber and protein in forages versus inorganic- and organic-N and P in ...

  1. 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

  2. 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.

  3. Who Becomes Established in Farming!

    ERIC Educational Resources Information Center

    Bjoraker, Walter T.; Martinson, Virgil O.

    1971-01-01

    Reports a study of the similarities and differences between individuals presently farming and those who have left farming in Wisconsin. Study is based on Virgil Martinson's 1970 Ph.D. dissertation. (SB)

  4. 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.

  5. Suitability and uncertainty of two models for the simulation of ammonia dispersion from a pig farm located in an area with frequent calm conditions

    NASA Astrophysics Data System (ADS)

    Theobald, Mark R.; Sanz-Cobena, Alberto; Vallejo, Antonio; Sutton, Mark A.

    2015-02-01

    We used two atmospheric dispersion models (ADMS and AERMOD) to simulate the short-range dispersion of ammonia emitted by two pig farms to assess their suitability in situations with frequent calm meteorological conditions. Simulations were carried out both using constant and temporally-varying emission rates to evaluate the effect on the model predictions. Monthly and annual mean concentrations predicted by the models at locations within one kilometre of the farms were compared with measured values. AERMOD predicted higher concentrations than ADMS (by a factor of 6-7, on average) and predicted the atmospheric concentrations more accurately for both the monthly and annual simulations. The differences between the concentrations predicted by the two models were mainly the result of different calm wind speed thresholds used by the models. The use of temporally-varying emission rates improved the performance of both models for the monthly and annual simulations with respect to the constant emission simulations. A Monte Carlo uncertainty analysis based on the inputs judged to be the most uncertain for the selected case study estimated a prediction uncertainty of ± a factor of two for both models with most of this due to uncertainty in emission rates.

  6. Infectious Swine Hepatitis E Virus Is Present in Pig Manure Storage Facilities on United States Farms, but Evidence of Water Contamination Is Lacking

    PubMed Central

    Kasorndorkbua, C.; Opriessnig, T.; Huang, F. F.; Guenette, D. K.; Thomas, P. J.; Meng, X.-J.; Halbur, P. G.

    2005-01-01

    Fresh feces, manure slurry (from earthen lagoons and/or concrete pits), and drinking and surface water samples were collected from 28 pig farms in the Midwestern United States. All samples were tested for hepatitis E virus (HEV) RNA by reverse transcription-PCR. Seven of 28 farms had fecal samples that contained HEV. Of 22 farms where pit samples were accessible, 15 contained HEV, and of 8 farms that had lagoons, 3 contained HEV. The highest virus titers were 10 and 103 genome equivalents per 60 ml of manure slurry in lagoon and pit samples, respectively. None of the water samples tested HEV positive. To determine the infectivity of the HEV found in the positive farm 19 lagoon (designated L19) or farm 12 pit (designated P12) samples, pigs were inoculated either intravenously (n = 3) or orally (n = 3) with the L19 or P12 manure slurry. Four pigs inoculated intravenously with prototype swine HEV served as positive controls. All positive-control pigs shed HEV in feces and 3 of 4 developed anti-HEV antibodies. Two pigs in the intravenously inoculated P12 group shed HEV in feces, and one of the pigs seroconverted to anti-HEV antibodies. None of the pigs in the negative-control, L19 oral, L19 intravenous, or P12 oral group shed HEV in feces. The findings indicate that HEV found in pig manure slurry was infectious when inoculated intravenously. Pit manure slurry is a potential source of HEV infection and for contamination of the environment. Contamination of drinking or surface water with HEV was not found on or near the pig farms. PMID:16332757

  7. A new analytical model for wind farm power prediction

    NASA Astrophysics Data System (ADS)

    Niayifar, Amin; Porte-Agel, Fernando

    2015-04-01

    In this study, a new analytical approach is presented and validated to predict wind farm power production. The new model assumes a Gaussian distribution for the velocity deficit in the wake which has been recently proposed by Bastankhah and Porté-Agel (2014). To estimate the velocity deficit in the wake, this model needs the local wake growth rate parameter which is calculated based on the local turbulence intensity in the wind farm. The interaction of the wakes is modeled by use of the velocity deficit superposition principle. Finally, the power curve is used to estimate the power production from the wind turbines. The wind farm model is compared to large-eddy simulation (LES) data of Horns Rev wind farm for a wide range of wind directions. Reasonable agreement between the proposed analytical model and LES data is obtained. This prediction is substantially better than the one obtained with common wind farm softwares such as WAsP.

  8. 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

  9. 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.

  10. A simulation study of two major events in the heliosphere during the present sunspot cycle

    NASA Technical Reports Server (NTRS)

    Akasofu, S. I.; Fillius, W.; Sun, W.; Fry, C.; Dryer, M.

    1985-01-01

    The two major disturbances in the heliosphere during the present sunspot cycle, the event of June to August, 1982, and the event of April to June, 1978, are simulated by the method developed by Hakamada and Akasofu (1982). Specifically, an attempt was made to simulate the effects of six major flares from three active regions in June and July, 1982, and April and May, 1978. A comparison of the results with the solar wind observations at Pioneer 12 (approximately 0.8 au), ISEE-3 (approximately 1 au), Pioneer 11 (approximately 7 to 13 au) and Pioneer 10 (approximately 16 to 28 au) suggests that some major flares occurred behind the disk of the sun during the two periods. The method provides qualitatively some information as to how such a series of intense solar flares can greatly disturb both the inner and outer heliospheres. A long lasting effect on cosmic rays is discussed in conjunction with the disturbed heliosphere.

  11. The Integrated Farm System Model: software for evaluating the performance, environmental impact and economics of farming systems

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The Integrated Farm System Model (IFSM) is a process level simulation of the performance of crop, beef and dairy farming systems that estimates major environmental impacts, production costs, and farm profitability. The IFSM simulates all major farm components on a process level. This enables the int...

  12. 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…

  13. A simulation study of two major events in the heliosphere during the present sunspot cycle

    NASA Technical Reports Server (NTRS)

    Akasofu, S. L.; Sun, W.; Fry, C.; Fillius, W.; Dryer, M.

    1985-01-01

    Disturbances in the heliosphere which occurred during two of the most active periods of the sun during the present solar cycle, in June and July 1982 and April and May 1978, are qualitatively simulated using the method of Hakamada and Akasofu (1982). A first-order spatial and temporal construction of flare-generated shocks and their multiple interactions with each other and with cororating interaction regions is obtained. A comparison of the results with solar wind observations from Pioneer 10, 11, and 12 suggests that some major flares occurred behind the solar disk during the two periods. The present method provides some qualitative information on how such a series of intense solar flares can greatly disturb both the inner and outer heliospheres. A long-lasting effect on cosmic rays which occurs in conjunction with such disturbances is discussed.

  14. A computer simulation of the prevention of the transmission of Toxoplasma gondii on swine farms using a feline T. gondii vaccine.

    PubMed

    Mateus-Pinilla, Nohra E; Hannon, Bruce; Weigel, Ronald M

    2002-09-10

    Transmission of Toxoplasma gondii on swine farms was investigated using a deterministic dynamic computer simulation model. A primary focus was to evaluate a feline T. gondii vaccine. Animal populations (swine and cats) were compartmentalized based on the stage of T. gondii infection. Simulations were run under conditions of closed and equilibrium population size. Model parameters were varied in a factorial experimental design to test the following hypotheses: T. gondii infection in finishing pigs decreases with (1) vaccination of susceptible cats, (2) an increase in the proportion of cats captured for vaccination, (3) a decrease in the initial number of cats, (4) a decrease in the initial T. gondii prevalence in cats and (5) a decrease in oocyst-survival time. Seeding conditions included a total of 10, 20, 30, 40 or 50 cats, initial T. gondii prevalences in cats of 30, 60 or 90%, vaccination of 0, 50 or 75% of the cats and two vaccination schedules (the field schedule from a prior trial and a weaning-vaccination schedule). Simulations were run at oocyst-survival times of 52, 39 and 26 weeks. T. gondii prevalence in finishing pigs was recorded every week for 10 years. The probability of elimination of T. gondii from finishing pigs increased with a decrease in the number of cats and a decrease in oocyst-survival time. The last-year average prevalence was used as the outcome in a multiple linear regression analysis. Decreased T. gondii prevalence in finishing pigs was the result of a decrease in the initial number of cats on the farm (squared semipartial correlation coefficient (sr(2))=47%), decreased oocyst survival (sr(2)=35%), using the weaning-vaccination schedule (sr(2)=7%) and vaccination versus non-vaccination (sr(2)=5%). Unexpectedly, the initial T. gondii prevalence in cats had no effect on T. gondii prevalence in finishing pigs. The simulation supports the field trial indicating vaccine effectiveness. However, vaccination had less impact on decreasing T

  15. 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

  16. 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.

  17. 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.

  18. 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.

  19. Low-cost tissue simulating phantoms with tunable, wavelength-dependent scattering properties (Conference Presentation)

    NASA Astrophysics Data System (ADS)

    Saager, Rolf B.; Quach, Alan; Rowland, Rebecca A.; Baldado, Melissa L.; Ponticorvo, Adrien; Durkin, Anthony J.

    2016-03-01

    Tissue-simulating phantoms provide the opportunity to evaluate the performance of optical and spectroscopic instruments under controlled experimental conditions. Recent efforts have advanced phantom fabrication methods to provide more tissue realistic phantoms, both in terms of a) incorporating absorbing agents that more faithfully mimic in vivo tissue chromophores spanning visible and near infrared regimes and b) accounting for multi-layer tissue structures with distinct optical properties. The spectral scattering properties in these phantoms, however, are typically based only on a single scattering agent, thereby locking the spectral scattering properties to a single particle size distribution. However, in both healthy tissue as well as pathologic tissue, regions of distinct and differentiated scattering may be present. With differing mean size and distribution of scattering objects in these tissue regions, the relative wavelength-dependent scattering spectra may vary. For example, partial thickness burns exhibit significant cellular damage and collagen denaturation that will significantly alter the wavelength-dependent scattering properties resembling large Mie-like scatterer distributions in both visible and near infrared regimes. We present a low-cost method to fabricate silicone tissue-simulating phantoms with tunable scattering spectra properties that span visible and near infrared wavelengths. We use optical polishing agents (white aluminum oxides powders) at various grit sizes to approximate Mie scattering across multiple mean particle sizes. Mean particle sizes used in this study range from 17-3 micron. The optical properties of these phantoms are verified using an integrating sphere in combination with inverse adding-doubling methods. The tolerances of this fabrication method will be discussed.

  20. 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.

  1. 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.

  2. MultiDarkLens 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, HuanYuan; Tessore, Nicolas

    2016-06-01

    In this paper we present a large database 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 database and new ones can be run upon request. Our database 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 realisations 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.

  3. Wind tunnel investigation on wind turbine wakes and wind farms

    NASA Astrophysics Data System (ADS)

    Iungo, G. V.; Coëffé, J.; Porté-Agel, F.

    2012-04-01

    The interaction between atmospheric boundary layer and wind farms leads to flow modifications, which need to be deeply characterized in order to relate them to wind farm performance. The wake flow produced from a wind farm is the result of a strong interaction between multiple turbine wakes, so that the wind farm configuration turns out to be one of the dominant features to enhance power production. For the present work a wind tunnel investigation was carried out with hot-wire anemometry and velocity measurements performed with multi-hole pressure probes. The tested wind farms consist of miniature three-bladed wind turbine models. Preliminarily, the wake flow generated from a single wind turbine is surveyed, which is characterized by a strong velocity defect lying in proximity of the wind turbine hub height. The wake gradually recovers by moving downstream; the characteristics of the incoming boundary layer and wind turbulence intensity can strongly affect the wake recovery, and thus performance of following wind turbines. An increased turbulence level is typically detected downstream of each wind turbine for heights comparable to the wind turbine blade top-tip. These wake flow fluctuations produce increased fatigue loads on the following wind turbines within a wind farm, which could represent a significant hazard for real wind turbines. Dynamics of vorticity structures present in wind turbine wakes are also investigated; particular attention is paid to the downstream evolution of the tip helicoidal vortices and to oscillations of the hub vortex. The effect of wind farm layout on power production is deeply investigated. Particular emphasis is placed on studying how the flow adjusts as it moves inside the wind farm and can affect the power production. Aligned and staggered wind farm configurations are analysed, also with varying separation distances in the streamwise and spanwise directions. The present experimental results are being used to test and guide the

  4. Measurements in support of wind farm simulations and power forecasts: The Crop/Wind-energy Experiments (CWEX)

    NASA Astrophysics Data System (ADS)

    Takle, E. S.; Rajewski, D. A.; Lundquist, J. K.; Gallus, W. A., Jr.; Sharma, A.

    2014-06-01

    The Midwest US currently is experiencing a large build-out of wind turbines in areas where the nocturnal low-level jet (NLLJ) is a prominent and frequently occurring feature. We describe shear characteristics of the NLLJ and their influence on wind power production. Reports of individual turbine power production and concurrent measurements of near-surface thermal stratification are used to turbine wake interactions and turbine interaction with the overlying atmosphere. Progress in forecasting conditions such as wind ramps and shear are discussed. Finally, the pressure perturbation introduced by a line of turbines produces surface flow convergence that may create a vertical velocity and hence a mesoscale influence on cloud formation by a wind farm.

  5. 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

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

    Technology Transfer Automated Retrieval System (TEKTRAN)

    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...

  7. 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

  8. Simulating present-day and future air quality as climate changes: Model evaluation

    NASA Astrophysics Data System (ADS)

    Dawson, John P.; Racherla, Pavan N.; Lynn, Barry H.; Adams, Peter J.; Pandis, Spyros N.

    The global-regional climate-air pollution modeling system (GRE-CAPS) has been developed, coupling an existing general circulation model/chemical transport model (GCM/CTM), a regional meteorological model, and a regional chemical transport model. This system is intended to enable studies of the effects of changes in climate, intercontinental transport, and emissions on regional and urban air quality. The GRE-CAPS system consists of the GISS II' GCM/CTM, the MM5 regional meteorological model, and the PMCAMx regional CTM. The modeling system is evaluated for the present day, with comparisons between model-predicted, measured ozone, and speciated PM 2.5 concentrations. The ability of the model to predict present-day concentrations of ozone and PM 2.5 is compared to that of PMCAMx when used for retrospective modeling. Comparisons between model-predicted temperatures and precipitation are also made. The model was used to simulate five present-day Januaries and six present-day Julys. The biases and errors in GRE-CAPS-predicted ozone concentrations were similar to those of PMCAMx when used for standard retrospective modeling. The fractional biases in mean daily peak ozone concentration and mean daily maximum 8-h average ozone concentration are both <10%. The model-predicted distribution of peak hourly and daily maximum 8-h average values agreed rather well with the measured distribution. There is less agreement between the model and measurements in the number of hours with ozone mixing ratios >70 or 80 ppb, though this is also the case with standard PMCAMx modeling. The predictions of PM 2.5 concentrations by GRE-CAPS were also of similar quality to those of PMCAMx driven by historical meteorology. The fractional biases in the predictions of total PM 2.5, sulfate, ammonium, and nitrate were all <25% in both January and July. The model agrees well with organic PM 2.5 measurements from the IMPROVE network, though there is less agreement with measurements from the STN network

  9. 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. PMID:22189467

  10. 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

  11. 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.

  12. 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.

  13. 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.

  14. Simulating CO2 effects on range plant growth and water use with GP-FARM-range model

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Adjustment of stocking rate is the primary management tool available to ranchers that has the biggest impact on rangeland vegetation and livestock production. Profitability and sustainability can be achieved by appropriately stocking cattle herds on native rangelands. Mechanistic simulation models...

  15. 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

  16. Linking on-farm change to catchment response using dynamic simulation modelling: assessing the impacts of farm-scale land management change on catchment-scale phosphorus transport processes and water-quality.

    NASA Astrophysics Data System (ADS)

    Rivers, M.; Clarendon, S.

    2012-04-01

    Australian Natural Resource Management and Agri-industry Development agencies have recently invested considerable resources into a number of research and development projects that have investigated the actual and potential economic, social and, particularly, environmental impacts of varying farming activities (with a strong focus on dairies) in a "catchment context". These activities have resulted in the development of a much-improved understanding of the likely impacts of changed farm management practices within the farms and regions in which they were investigated, as well as the development of a number of conceptual models which place dairy farming within this broader catchment context. The project discussed in this paper was charged with the objective of transforming these conceptual models of dairy farm nutrient management and transport processes into a more temporally and spatially dynamic model. This could then be 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. This paper describes the series of dynamic models and farm management - land use scenarios which were executed to examine these issues. Models were developed, validated and calibrated for the Peel-Harvey catchment in Western Australia and the Gippsland and Latrobe (a sub-catchment of Gippsland) catchments in Victoria. Scenarios which range from simple, on-farm riparian management, through changes in fertiliser application rates, to gross changes in the land use mosaic were examined and described in terms which included changes to phosphorus (P) loss rates at the farm scale, the relative contributions to catchment P loads from dairying and, ultimately, changes to downstream water quality. A comprehensive suite of scenarios and policy options was examined but, in summary, the results indicate that whilst

  17. Farm Equipment

    NASA Technical Reports Server (NTRS)

    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.

  18. 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.

  19. 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.

    2011-11-01

    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 variability between their results. Studying a heterogeneous variable such as permafrost implies conducting analysis at a smaller spatial scale compared with climate models resolution. Our approach consists of applying statistical downscaling methods (SDMs) on large- or regional-scale atmospheric variables provided by climate models, leading to local-scale permafrost modelling. Among the SDMs, we first choose a transfer function approach based on Generalized Additive Models (GAMs) to produce high-resolution climatology of air temperature at the surface. Then we define permafrost distribution over Eurasia by air temperature conditions. In a first validation step on present climate (CTRL period), this method shows some limitations with non-systematic improvements in comparison with the large-scale fields. So, we develop an alternative method of statistical downscaling based on a Multinomial Logistic GAM (ML-GAM), which directly predicts the occurrence probabilities of local-scale permafrost. The obtained permafrost distributions appear in a better agreement with CTRL data. In average for the nine PMIP2 models, we measure a global agreement with CTRL permafrost data that is better when using ML-GAM than when applying the GAM method with air temperature conditions. In both cases, the provided local information reduces the variability between climate models results. This also confirms that a simple relationship between permafrost and the air temperature only is not always sufficient to represent local-scale 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. The prediction of the SDMs (GAM

  20. 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

  1. The Enhancement of Simulation Based Learning Exercises through Formalised Reflection, Focus Groups and Group Presentation

    ERIC Educational Resources Information Center

    Mawdesley, M.; Long, G.; Al-jibouri, S.; Scott, D.

    2011-01-01

    Computer based simulations and games can be useful tools in teaching aspects of construction project management that are not easily transmitted through traditional lecture based approaches. However, it can be difficult to quantify their utility and it is essential to ensure that students are achieving the learning outcomes required rather than…

  2. 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)

  3. Simulations of present and future climates in the western U.S. with four nested regional climate models

    SciTech Connect

    Duffy, P B; Arritt, R W; Coquard, J; Gutowski, W; Han, J; Iorio, J; Kim, J; Leung, L R; Roads, J; Zeledon, E

    2004-06-15

    We analyze simulations of present and future climates in the western U.S. performed with four regional climate models (RCMs) nested within two global ocean-atmosphere climate models. Our primary goal is to assess the range of regional climate responses to increased greenhouse gases in available RCM simulations. The four RCMs used different geographical domains, different increased greenhouse gas scenarios for future-climate simulations, and (in some cases) different lateral boundary conditions. For simulations of the present climate, we compare RCM results to observations and to results of the GCM that provided lateral boundary conditions to the RCM. For future-climate (increased greenhouse gas) simulations, we compare RCM results to each other and to results of the driving GCMs. When results are spatially averaged over the western U.S., we find that the results of each RCM closely follow those of the driving GCM in the same region, in both present and future climates. In present-climate simulations, the RCMs have biases in spatially-averaged simulated precipitation and near-surface temperature that seem to be very close to those of the driving GCMs. In future-climate simulations, the spatially-averaged RCM-projected responses in precipitation and near-surface temperature are also very close to those of the respective driving GCMs. Precipitation responses predicted by the RCMs are in many regions not statistically significant compared to interannual variability. Where the predicted precipitation responses are statistically significant, they are positive. The models agree that near-surface temperatures will increase, but do not agree on the spatial pattern of this increase. The four RCMs produce very different estimates of water content of snow in the present climate, and of the change in this water content in response to increased greenhouse gases.

  4. 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…

  5. 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)

  6. The Persistence of Family Farming Areas.

    ERIC Educational Resources Information Center

    Hart, John Fraser

    1987-01-01

    Presents data on the number, value, and distribution of the family farm between 1950 and 1982. Shows changes using five maps and two charts. Concludes that the geographical distribution of family farming areas has remained stable since World War II even though some farming systems have changed dramatically. (JDH)

  7. Simulation of Present-Climate Precipitation: Parameter Perturbations and Internal Variability with the GFDL Model

    NASA Astrophysics Data System (ADS)

    Zamboni, L.; Neelin, J. D.; Jacob, R. L.; Zhao, M.; Held, I.; Moore, T. L.

    2014-12-01

    We found that internal variability is a substantial source of uncertainty for local climatological precipitation in an ensemble of perturbed physics experiments (PPE) in which we also perturbed the atmospheric initial conditions. The ensemble consists of about seventy 50-year long AMIP simulations performed with the GFDL model at 1x1 degree resolution. Our goal is to describe the dependence of the local precipitation climatology to the value of each parameter being perturbed in the ensemble; and we found that a quadratic dependence is appropriate for the entrainment in convective clouds (Fig.1a) with the quadratic term acting to compensate the effect of the linear term: the magnitude of the latter is in fact 20-30% larger and of opposite sign in all major convective areas in the Tropics. About 50% of the grid points show such behavior (Fig.1b) when an ensemble of initial conditions is employed. To assess the impact of internal variability we repeated the analysis using only one run for each parameter value and found that the confidence with which the fitting parameters are established is strongly decreased: a difference in the magnitude of the reconstructed precipitation of about 10-30% is obtained, when precipitation is evaluated at the standard value of the entrainment coefficient (Fig.1c); and the number of grid points in which the null hypothesis of "no quadratic dependence" is rejected halves (Fig.1d). Preliminary results on the joint impact of internal variability and temporal span of the simulations indicate that an increased uncertainty of about 10% occurs when only 20 of the 50 years of simulations are considered. Lastly, in exploring model optimization we found that a PPE often cannot be discerned from the internal variability in a simulation length of 50 years.

  8. 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.

  9. 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.

  10. 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

  11. 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.

  12. Optimal control of energy extraction in LES of large wind farms

    NASA Astrophysics Data System (ADS)

    Meyers, Johan; Goit, Jay; Munters, Wim

    2014-11-01

    We investigate the use of optimal control 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 and in finite 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 an actuator-disk representation of wind turbines. Simulations are performed in our in-house pseudo-spectral code SP-Wind. For the optimal control study, we consider the dynamic control of turbine-thrust coefficients in the 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. In a first infinite wind-farm case, we find that farm power is increases by approximately 16% over one hour of operation. This comes at the cost of a deceleration of the outer layer of the boundary layer. A detailed analysis of energy balances is presented, and a comparison is made between infinite and finite farm cases, for which boundary layer entrainment plays an import role. The authors acknowledge support from the European Research Council (FP7-Ideas, Grant No. 306471). Simulations were performed on the computing infrastructure of the VSC Flemish Supercomputer Center, funded by the Hercules Foundation and the Flemish Govern.

  13. Evaluation of INPRES--Intraoperative Presentation of surgical planning and simulation results.

    PubMed

    Salb, Tobias; Brief, Jakob; Burgert, Oliver; Gockel, Tilo; Hassfeld, Stefan; Muehling, Joachim; Dillmann, Ruediger

    2003-01-01

    In this paper we present fundamental results of the first evaluation of INPRES in a laboratory environment. While the system itself--an HMD-based approach for intraoperative augmented reality in head and neck surgery--has been described elsewhere several times, this paper will focus on methods and outcome of recently accomplished test procedures. PMID:15455913

  14. 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

  15. Modelling pastoral farm systems--scaling from farm to region.

    PubMed

    Vogeler, Iris; Vibart, Ronaldo; Mackay, Alec; Dennis, Samuel; Burggraaf, Vicki; Beautrais, Josef

    2014-06-01

    Farm system and nutrient budget models are increasingly being used to inform and evaluate policy options on the impacts of land use change on regional environmental and economic performance. In this study, the common approach of up-scaling representative farm systems to a regional scale, with a limited input of resource information, was compared with a new approach that links a geospatial land resource information data base (NZLRI, Agribase™) that includes independent estimates of the productive capacity of land parcels, with individual farm-scale simulation (Farmax® Pro and Farmax® Dairy Pro) and nutrient budgeting models (Overseer®). The Southland region of New Zealand, which is currently undergoing enormous land use change, was used as a case study. Model outputs from the new approach showed increased profit of about 75% for the region if the current land area under dairying increases from 16% to 45%, with the shift to dairy constrained to high pasture production classes only. Environmental impacts associated with the change were substantial, with nitrate leaching estimated to increase by 35% and greenhouse gas emissions by 25%. Up-scaling of representative farm systems to the regional scale with limited input of resource information predicted lower potential regional profit and higher N leaching from dairy conversion. The new approach provides a farm scale framework that could easily be extended to include different systems, different levels of farming performance and the use of mitigation technologies. PMID:24657579

  16. 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

  17. 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

  18. FARM : an automated malware analysis environment.

    SciTech Connect

    Van Randwyk, Jamie A.; Lloyd, Levi; Vanderveen, Keith B.; Chiang, Ken

    2008-10-01

    We present the forensic analysis repository for malware (FARM), a system for automating malware analysis. FARM leverages existing dynamic and static analysis tools and is designed in a modular fashion to provide future extensibility. We present our motivations for designing the system and give an overview of the system architecture. We also present several common scenarios that detail uses for FARM as well as illustrate how automated malware analysis saves time. Finally, we discuss future development of this tool.

  19. FARM : an automated malware analysis environment.

    SciTech Connect

    Van Randwyk, Jamie A.; Lloyd, Levi; Vanderveen, Keith B.; Chiang, Ken

    2008-08-01

    We present the forensic analysis repository for malware (FARM), a system for automating malware analysis. FARM leverages existing dynamic and static analysis tools and is designed in a modular fashion to provide future extensibility. We present our motivations for designing the system and give an overview of the system architecture. We also present several common scenarios that detail uses for FARM as well as illustrate how automated malware analysis saves time. Finally, we discuss future development of this tool.

  20. Simulating the Past, Present and Future of the Upper Troposphere and Lower Stratosphere

    NASA Astrophysics Data System (ADS)

    Gettelman, Andrew; Hegglin, Michaela

    2010-05-01

    A comprehensive assessment of coupled chemistry climate model (CCM) performance in the upper troposphere and lower stratosphere has been conducted with 18 models. Both qualitative and quantitative comparisons of model representation of UTLS dynamical, radiative and chemical structure have been conducted, using a collection of quantitative grading techniques. The models are able to reproduce the observed climatology of dynamical, radiative and chemical structure in the tropical and extratropical UTLS, despite relatively coarse vertical and horizontal resolution. Diagnostics of the Tropical Tropopause Layer (TTL), Tropopause Inversion Layer (TIL) and Extra-tropical Transition Layer (ExTL) are analyzed. The results provide new insight into the key processes that govern the dynamics and transport in the tropics and extra-tropicsa. The presentation will explain how models are able to reproduce key features of the UTLS, what features they do not reproduce, and why. Model trends over the historical period are also assessed and interannual variability is included in the metrics. Finally, key trends in the UTLS for the future with a given halogen and greenhouse gas scenario are presented, indicating significant changes in tropopause height and temperature, as well as UTLS ozone concentrations in the 21st century due to climate change and ozone recovery.

  1. 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. PMID:25459797

  2. 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.

  3. 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.

  4. 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.

  5. 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

  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. Whole farm assessment of alternative cropping and feeding strategies

    Technology Transfer Automated Retrieval System (TEKTRAN)

    A change in cropping and feeding practices can affect the performance, economics and environmental impacts of a dairy farm. A whole farm assessment of all major effects can only be done through process level simulation of the production system. The Integrated Farm System Model provides a research an...

  8. A new analytical model for wind farm power prediction

    NASA Astrophysics Data System (ADS)

    Niayifar, Amin; Porté-Agel, Fernando

    2015-06-01

    In this study, a new analytical approach is presented and validated to predict wind farm power production. The new model is an extension of the recently proposed by Bastankhah and Porté-Agel for a single wake. It assumes a self-similar Gaussian shape of the velocity deficit and satisfies conservation of mass and momentum. To estimate the velocity deficit in the wake, this model needs the local wake growth rate parameter which is calculated based on the local turbulence intensity in the wind farm. The interaction of the wakes is modeled by use of the velocity deficit superposition principle. Finally, the power curve is used to estimate the power production from the wind turbines. The wind farm model is compared to large-eddy simulation (LES) data and measurments of Horns Rev wind farm for a wide range of wind directions. Reasonable agreement between the proposed analytical model, LES data and measurments is obtained. This prediction is also found to be substantially better than the one obtained with a commonly used wind farm wake model.

  9. 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.

  10. Present and Future Surface Climate in the Western U.S. as Simulated by 15 Global Climate Models

    SciTech Connect

    Coquard, J; Duffy, P B; Taylor, K E; Iorio, J P

    2004-08-09

    We analyze results of 15 global climate simulations contributed to the Coupled Model Intercomparison Project (CMIP). Focusing on the western U.S., we consider both present climate simulations and predicted responses to increasing atmospheric CO{sub 2}. The models vary in their ability to predict the present climate. Over the western U.S., a few models produce a seasonal cycle for spatially-averaged temperature and/or precipitation in good agreement with observational data. Other models tend to overpredict precipitation in the winter or exaggerate the amplitude of the seasonal cycle of temperature. The models also differ in their ability to reproduce the spatial patterns of temperature and precipitation in the U.S. Considering the monthly mean precipitation responses to doubled atmospheric CO{sub 2}, averaged over the western U.S., we find some models predict increases while others predict decreases. The predicted temperature response, on the other hand, is invariably positive over this region; however, for each month, the range of values given by the different models is large compared to the mean model response. We look for possible relationships between the models' temperature and precipitation responses to doubled CO{sub 2} concentration and their ability to simulate some aspects of the present climate. We find that these relationships are weak, at best. The precipitation response over the western U.S. in DJF and the precipitation response over the mid- and tropical latitudes seem to be correlated with the RMS error in simulated present-day precipitation, also calculated over the mid- and tropical latitudes. However, considering only the responses of the models with the smallest RMS errors does not provide a different estimate of the precipitation response to a doubled CO{sub 2} concentration, because even among the most accurate models, the range of model responses is so large. For temperature, we find that models that have smaller RMS errors in present

  11. 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

  12. 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.

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

    Technology Transfer Automated Retrieval System (TEKTRAN)

    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...

  14. 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

  15. Sensitivity analysis for models of greenhouse gas emissions at farm level. Case study of N(2)O emissions simulated by the CERES-EGC model.

    PubMed

    Drouet, J-L; Capian, N; Fiorelli, J-L; Blanfort, V; Capitaine, M; Duretz, S; Gabrielle, B; Martin, R; Lardy, R; Cellier, P; Soussana, J-F

    2011-11-01

    Modelling complex systems such as farms often requires quantification of a large number of input factors. Sensitivity analyses are useful to reduce the number of input factors that are required to be measured or estimated accurately. Three methods of sensitivity analysis (the Morris method, the rank regression and correlation method and the Extended Fourier Amplitude Sensitivity Test method) were compared in the case of the CERES-EGC model applied to crops of a dairy farm. The qualitative Morris method provided a screening of the input factors. The two other quantitative methods were used to investigate more thoroughly the effects of input factors on output variables. Despite differences in terms of concepts and assumptions, the three methods provided similar results. Among the 44 factors under study, N(2)O emissions were mainly sensitive to the fraction of N(2)O emitted during denitrification, the maximum rate of nitrification, the soil bulk density and the cropland area. PMID:21296472

  16. 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

  17. 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.

  18. 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…

  19. 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…

  20. Integrated Farm System Model: Reference Manual, Version 2.1

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The Integrated Farm System Model simulates the major biological and physical processes of a crop, beef, or dairy farm. Crop production, feed use, and the return of manure nutrients back to the land are simulated over each of 25 years of weather. Growth and development of alfalfa, grass, corn, soybea...

  1. Farm Safety (For Parents)

    MedlinePlus

    ... wheels or blind spots. Because adults who are operating machinery may be unable to see or hear ... a tractor and farm vehicle safety course before operating farm vehicles. Finally, teach older kids how to ...

  2. 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)

  3. 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. PMID:16154255

  4. Energy integrated farm system technical summary report

    SciTech Connect

    Breckenridge, R.P.; Price, D.R.; Sherwood, R.K.; Thompson, W.N.

    1987-03-01

    The Energy Integrated Farm System program was established by the Department of Energy in 1980 in response to the hardship imposed on US farmers by high fuel costs and unreliable fuel supplies. The program investigated the feasibility of integrating energy conservation practices with on-farm energy production to reduce farm energy consumption and make farms more energy self-sufficient. Seven farms located in various geographical regions in the US and Puerto Rico participated in the program. Each of these farms developed an energy integrated farm system project that used a unique combination of energy production and energy conservation methods to supply energy to the farm and reduce the farm's dependence on energy produced from nonrenewable sources such as coal and oil. Methods used at these projects included conservation tillage, solar heating, waste heat recovery, methane digestion, electricity production from biogas, alcohol fuel production, fluidized-bed combustion of crop wastes, and computer-aided conservation irrigation. This report is a summary of the seven technical manuals prepared at the conclusion of the projects. It presents highlights and results, provides an overview of successes and problems, and lists recommendations.

  5. Planetary boundary layer energetics simulated from a regional climate model over Europe for present climate and climate change conditions

    NASA Astrophysics Data System (ADS)

    Sánchez, E.; Yagüe, C.; Gaertner, M. A.

    2007-01-01

    This paper presents a description of the planetary boundary layer (PBL) for current (1960-1990) and future (2070-2100) climate periods as obtained from a regional climate model (RCM) centered on the Mediterranean basin. Vertically integrated turbulent kinetic energy (TKEZ) and boundary layer height (z i ) are used to describe PBL energetics. Present climate shows a TKEZ annual cycle with a clear summer maximum for southern regions, while northern regions of Europe exhibit a smoother or even a lack of cycle. Future climate conditions exhibit a similar behaviour, with an increase in the summer maximum peaks. A detailed analysis of summer surface climate change energetics over land shows an increased Bowen ratio and decreases in the evaporative fraction. The enhanced sensible heat flux responsible for these results causes an energy surplus inside the PBL, resulting in increased convective activity and corresponding TKEZ. These results are consistent with temperature increases obtained by several other model simulations, and also indicate that changes in the turbulent transport from the PBL to the free troposphere can affect atmospheric circulations.

  6. 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…

  7. 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 Soviet Russia.…

  8. 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

  9. 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

  10. 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…

  11. 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. PMID:25979283

  12. Farm noise emissions during common agricultural activities.

    PubMed

    Depczynski, J; Franklin, R C; Challinor, K; Williams, W; Fragar, L J

    2005-08-01

    Noise injury in agriculture is a significant yet often unrecognized problem. Many farmers, farm workers, and family members are exposed to noise levels above recommended levels and have greater hearing loss than their non-farming contemporaries. The aim of this study was to gather up-to-date information on farm noise levels and to enhance the quality of information available to assist farmers in reducing noise exposure and meeting Occupational Health and Safety (OHS) regulations regarding noise management. Farm visits were conducted on 48 agricultural establishments that produce a range of commodities. Noise levels were measured at the ears of operators and bystanders involved in typical activities on farms. The average and peak noise levels were measured for 56 types of machinery or sites of farming activity, totaling 298 separate items and activities. Common noise hazards identified included firearms, tractors without cabs, workshop tools, small motors (e.g., chainsaws, augers, pumps), manual handling of pigs, shearing sheds, older cabbed tractors, and heavy machinery such as harvesters, bulldozers, and cotton module presses. We found that use of firearms without hearing protection presents a pressing hearing health priority. However, farming activities involving machinery used for prolonged periods also present significant risks to farmers' hearing health. Noise management strategies on the farm are essential in order to prevent noise injury among farmers. PMID:16184791

  13. 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 . PMID:26306875

  14. 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.

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

    Technology Transfer Automated Retrieval System (TEKTRAN)

    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...

  16. 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

  17. 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

  18. 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.

  19. 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

  20. 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…

  1. SMITH FARM FROM COOK ROAD, LOOKING WEST. (The farm buildings ...

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

    SMITH FARM FROM COOK ROAD, LOOKING WEST. (The farm buildings from left to right are: granary, garage, Gould house, and barn. The Olympic Mountains are visible in the distance.) - Smith Farm, 399 Ebey Road, Coupeville, Island County, WA

  2. Effect of no-till farming on soil water intake

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Rainfall simulation and ponded infiltrometer methods were used to investigate the infiltration characteristics of no-till vs. conventional tillage farms. Seven pairs of no-till and conventional till farms under a corn-soybean rotation were selected on soils ranging from sandy loam to silty clay loam...

  3. Assessing the Influence of Farm Women's Self-Identity on Task Allocation and Decision Making.

    ERIC Educational Resources Information Center

    Bokemeier, Janet; Garkovich, Lorraine

    1987-01-01

    Uses data from survey of 880 Kentucky farm women to present theoretical framework integrating microsocial, household economy, and farm structural perspectives to explain gender allocation of farm-specific tasks and decision making. Finds self-identity validated by participation in farm tasks/decision making, but, overall, women indicate low levels…

  4. 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.

  5. 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.

  6. 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.

  7. Occupations and the Farm.

    ERIC Educational Resources Information Center

    Ewert-Krocker, Laurie

    2001-01-01

    Describes "occupation" as a Montessori term, which the Hershey Montessori Farm School, in Huntsburg, Ohio, has adopted for any task arising from the needs of the farm that then generates a scientific or historic study. Includes lists of occupations pursued during 2000-2001 and samples of record forms students used to manage their work. (Author/KB)

  8. Farming for Net Profit

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Many factors can influence farm management decisions. One important factor is economic returns. Staying in farming requires dealing with a wide range of changing conditions. Given these changing conditions, it is particularly important to “get the big decisions right”. This requires evaluating impac...

  9. 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.

  10. 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,…

  11. Occupational Hazards of Farming

    PubMed Central

    White, Gill; Cessna, Allan

    1989-01-01

    A number of occupational hazards exist for the farmer and farm worker. They include the hazards of farm machinery, biologic and chemical hazards, and social and environmental stresses. Recognizing of these hazards will help the family physician care for farmers and their families. PMID:21248929

  12. 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…

  13. 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.

  14. 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.

  15. 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.

  16. 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.

  17. 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.

  18. 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.

  19. 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

  20. 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

  1. Climate Model Simulation of Present and Future Extreme Events in Latin America and the Caribbean: What Spatial Resolution is Required?

    NASA Astrophysics Data System (ADS)

    Rowe, C. M.; Oglesby, R. J.; Mawalagedara, R.; Mohammad Abadi Kamarei, A.

    2015-12-01

    Latin America and the Caribbean are at risk of extreme climate events, including flooding rains, damaging winds, drought, heat waves, and in high elevation mountainous regions, excessive snowfalls. The causes of these events are numerous - flooding rains and damaging winds are often associated with tropical cyclones, but also can occur, either separately or in tandem, due to smaller, more localized storms. Similarly, heat waves and droughts can be large scale or localized, and frequently occur together (as excessive drying can lead to enhanced heating, while enhanced heating in turn promotes additional drying). Even in the tropics, extreme snow and ice events can have severe consequences due to avalanches, and also impact water resources. Understanding and modeling the climate controls behind these extreme events requires consideration of a range of time and space scales. A common strategy is to use a global climate model (GCM) to simulate the large-scale (~100km) daily atmospheric controls on extreme events. A limited area, high resolution regional climate model (RCM) is then employed to dynamically downscale the results, so as to better incorporate the influence of topography and, secondarily, the nature of the land cover. But what resolution is required to provide the necessary results, i.e., minimize biases due to improper resolution? In conjunction with our partners from participating Latin American and Caribbean nations, we have made an extensive series of simulations, both region-wide and for individual countries, using the WRF regional climate model to downscale output from a variety of GCMs, as well as Reanalyses (as a proxy for observations). The simulations driven by the Reanalyses are used for robust model verification against actual weather station observations. The simulations driven by GCMs are designed to provide projections of future climate, including importantly how the nature and number of extreme events may change through coming decades. Our

  2. 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.

  3. Low flow venous malformation lesion presented with medial canthal swelling simulating swelling of the lacrimal sac origin: A case report

    PubMed Central

    ALSwaina, Nayef F.; ALSuhaibani, Adel H.

    2015-01-01

    Low flow venous malformation lesions (e.g. cavernous venous malformations) are commonly seen in the orbit and peri-orbital area. Common conditions may present with unexpected presentation. Here we report a 50 years old male patient with low flow venous malformation lesion presented with medial canthal swelling similar to the swelling typically seen in lacrimal sac related pathologies. PMID:26309438

  4. A stochastic dynamic simulation model including multi-trait genetics to estimate genetic, technical and financial consequences of dairy farm reproduction and selection strategies

    Technology Transfer Automated Retrieval System (TEKTRAN)

    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...

  5. 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…

  6. Environmental and Economic Comparisons of Manure Application Methods on Dairy Farms

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Field measurements and a farm simulation model were used to compare the environmental and economic impacts of using alternative manure application methods on dairy farms. The Integrated Farm System Model was able to represent the corn silage production, water balance, volatile ammonia N loss, nitrat...

  7. 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

  8. 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.

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

    Technology Transfer Automated Retrieval System (TEKTRAN)

    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...

  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. 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

  12. 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.

  13. 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.

  14. 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.

  15. 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)

  16. Farm Health and Safety

    MedlinePlus

    ... the United States. Farms have many health and safety hazards, including Chemicals and pesticides Machinery, tools and ... inspection and maintenance can help prevent accidents. Using safety gloves, goggles and other protective equipment can also ...

  17. National Farm Medicine Center

    MedlinePlus

    Research Areas Applied Sciences Biomedical Informatics Clinical Research Epidemiology Farm Medicine Human Genetics Oral-Systemic Health Clinical Trials Services CM&R Research Lab Research Compliance Research Integrity & ...

  18. 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.

  19. 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.

  20. 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. PMID:24183560

  1. 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.

  2. Subjective results of a simulator evaluation using synthetic terrain imagery presented on a helmet-mounted display

    NASA Astrophysics Data System (ADS)

    Rate, Christopher R.; Probert, Andrew; Wright, David; Corwin, William H.; Royer, Rick

    1994-06-01

    Combat mission scenarios require pilots to maneuver their aircraft over and around various terrain features at high speeds and low altitudes day, night, or in adverse meteorological conditions. While current systems (e.g., Night Vision Goggles and FLIR) provide some support for the pilot, they are not adequate in many weather conditions. However, the effects of adverse weather can be overcome using the U. S. Defense Mapping Agency's digital terrain elevation database to create a synthetic terrain image (STI). The concept of synthetically derived terrain imagery, projected as background on a Helmet-Mounted Display, was investigated in regards to its utility for enhancing pilot terrain awareness. An initial study using four Lockheed pilots and six USAF pilots was conducted to determine subjective preference of STI formats. A follow-on study, using two preferred formats, evaluated STI in a full-mission simulation environment. Six F-16 pilots completed a half day of training and a one day evaluation. Data was collected on missions involving low level navigation, followed by a laser guided bomb loft or offset roll- in dive bomb attack. Thirteen missions per pilot were completed including bomb runs using LANTIRN without STI. All the runs were at night with either 'poor' or 'good' FLIR conditions over rough or moderately rolling terrain. The evaluation indicated that pilots found STI to be useful and offered real-time support for low level navigation. Some problems still exist (e.g., field of view of HMD), which will be investigated in future studies.

  3. 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

  4. Certified safe farm: identifying and removing hazards on the farm.

    PubMed

    Rautiainen, R H; Grafft, L J; Kline, A K; Madsen, M D; Lange, J L; Donham, K J

    2010-04-01

    This article describes the development of the Certified Safe Farm (CSF) on-farm safety review tools, characterizes the safety improvements among participating farms during the study period, and evaluates differences in background variables between low and high scoring farms. Average farm review scores on 185 study farms improved from 82 to 96 during the five-year study (0-100 scale, 85 required for CSF certification). A total of 1292 safety improvements were reported at an estimated cost of $650 per farm. A wide range of improvements were made, including adding 9 rollover protective structures (ROPS), 59 power take-off (PTO) master shields, and 207 slow-moving vehicle (SMV) emblems; improving lighting on 72 machines: placing 171 warning decals on machinery; shielding 77 moving parts; locking up 17 chemical storage areas, adding 83 lockout/tagout improvements; and making general housekeeping upgrades in 62 farm buildings. The local, trained farm reviewers and the CSF review process overall were well received by participating farmers. In addition to our earlier findings where higher farm review scores were associated with lower self-reported health outcome costs, we found that those with higher farm work hours, younger age, pork production in confinement, beef production, poultry production, and reported exposure to agrichemicals had higher farm review scores than those who did not have these characteristics. Overall, the farm review process functioned as expected. encouraging physical improvements in the farm environment, and contributing to the multi-faceted CSF intervention program. PMID:20503809

  5. 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).

  6. Modeling of present-day atmosphere and ocean non-tidal de-aliasing errors for future gravity mission simulations

    NASA Astrophysics Data System (ADS)

    Dobslaw, Henryk; Bergmann-Wolf, Inga; Forootan, Ehsan; Dahle, Christoph; Mayer-Gürr, Torsten; Kusche, Jürgen; Flechtner, Frank

    2016-05-01

    A realistically perturbed synthetic de-aliasing model consistent with the updated Earth System Model of the European Space Agency is now available over the period 1995-2006. The dataset contains realizations of (1) errors at large spatial scales assessed individually for periods 10-30, 3-10, and 1-3 days, the S1 atmospheric tide, and sub-diurnal periods; (2) errors at small spatial scales typically not covered by global models of atmosphere and ocean variability; and (3) errors due to physical processes not represented in currently available de-aliasing products. The model is provided in two separate sets of Stokes coefficients to allow for a flexible re-scaling of the overall error level to account for potential future improvements in atmosphere and ocean mass variability models. Error magnitudes for the different frequency bands are derived from a small ensemble of four atmospheric and oceanic models. For the largest spatial scales up to d/o = 40 and periods longer than 24 h, those error estimates are approximately confirmed from a variance component estimation based on GRACE daily normal equations. Future mission performance simulations based on the updated Earth System Model and the realistically perturbed de-aliasing model indicate that for GRACE-type missions only moderate reductions of de-aliasing errors can be expected from a second satellite pair in a shifted polar orbit. Substantially more accurate global gravity fields are obtained when a second pair of satellites in an moderately inclined orbit is added, which largely stabilizes the global gravity field solutions due to its rotated sampling sensitivity.

  7. 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?

  8. 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.

  9. 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.

  10. 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.