U.S. DOE methodology for the development of geologic storage potential for carbon dioxide at the national and regional scale

USGS Publications Warehouse

Goodman, Angela; Hakala, J. Alexandra; Bromhal, Grant; Deel, Dawn; Rodosta, Traci; Frailey, Scott; Small, Michael; Allen, Doug; Romanov, Vyacheslav; Fazio, Jim; Huerta, Nicolas; McIntyre, Dustin; Kutchko, Barbara; Guthrie, George

2011-01-01

A detailed description of the United States Department of Energy (US-DOE) methodology for estimating CO2 storage potential for oil and gas reservoirs, saline formations, and unmineable coal seams is provided. The oil and gas reservoirs are assessed at the field level, while saline formations and unmineable coal seams are assessed at the basin level. The US-DOE methodology is intended for external users such as the Regional Carbon Sequestration Partnerships (RCSPs), future project developers, and governmental entities to produce high-level CO2 resource assessments of potential CO2 storage reservoirs in the United States and Canada at the regional and national scale; however, this methodology is general enough that it could be applied globally. The purpose of the US-DOE CO2 storage methodology, definitions of storage terms, and a CO2 storage classification are provided. Methodology for CO2 storage resource estimate calculation is outlined. The Log Odds Method when applied with Monte Carlo Sampling is presented in detail for estimation of CO2 storage efficiency needed for CO2 storage resource estimates at the regional and national scale. CO2 storage potential reported in the US-DOE's assessment are intended to be distributed online by a geographic information system in NatCarb and made available as hard-copy in the Carbon Sequestration Atlas of the United States and Canada. US-DOE's methodology will be continuously refined, incorporating results of the Development Phase projects conducted by the RCSPs from 2008 to 2018. Estimates will be formally updated every two years in subsequent versions of the Carbon Sequestration Atlas of the United States and Canada.

Study of the modifications needed for effective operation NASTRAN on IBM virtual storage computers

NASA Technical Reports Server (NTRS)

Mccormick, C. W.; Render, K. H.

1975-01-01

The necessary modifications were determined to make NASTRAN operational under virtual storage operating systems (VS1 and VS2). Suggested changes are presented which will make NASTRAN operate more efficiently under these systems. Estimates of the cost and time involved in design, coding, and implementation of all suggested modifications are included.

Optical Data Storage Capabilities of Bacteriorhodopsin

NASA Technical Reports Server (NTRS)

Gary, Charles

1998-01-01

We present several measurements of the data storage capability of bacteriorhodopsin films to help establish the baseline performance of this material as a medium for holographic data storage. In particular, we examine the decrease in diffraction efficiency with the density of holograms stored at one location in the film, and we also analyze the recording schedule needed to produce a set of equal intensity holograms at a single location in the film. Using this information along with the assumptions about the performance of the optical system, we can estimate potential data storage densities in bacteriorhodopsin.

A low-cost iron-cadmium redox flow battery for large-scale energy storage

NASA Astrophysics Data System (ADS)

Zeng, Y. K.; Zhao, T. S.; Zhou, X. L.; Wei, L.; Jiang, H. R.

2016-10-01

The redox flow battery (RFB) is one of the most promising large-scale energy storage technologies that offer a potential solution to the intermittency of renewable sources such as wind and solar. The prerequisite for widespread utilization of RFBs is low capital cost. In this work, an iron-cadmium redox flow battery (Fe/Cd RFB) with a premixed iron and cadmium solution is developed and tested. It is demonstrated that the coulombic efficiency and energy efficiency of the Fe/Cd RFB reach 98.7% and 80.2% at 120 mA cm-2, respectively. The Fe/Cd RFB exhibits stable efficiencies with capacity retention of 99.87% per cycle during the cycle test. Moreover, the Fe/Cd RFB is estimated to have a low capital cost of 108 kWh-1 for 8-h energy storage. Intrinsically low-cost active materials, high cell performance and excellent capacity retention equip the Fe/Cd RFB to be a promising solution for large-scale energy storage systems.

Temperature dependency of the thermal conductivity of porous heat storage media

NASA Astrophysics Data System (ADS)

Hailemariam, Henok; Wuttke, Frank

2018-04-01

Analyzing the variation of thermal conductivity with temperature is vital in the design and assessment of the efficiency of sensible heat storage systems. In this study, the temperature variation of the thermal conductivity of a commercial cement-based porous heat storage material named - Füllbinder L is analyzed in saturated condition in the temperature range between 20 to 70°C (water based storage) with a steady state thermal conductivity and diffusivity meter. A considerable decrease in the thermal conductivity of the saturated sensible heat storage material upon increase in temperature is obtained, resulting in a significant loss of system efficiency and slower loading/un-loading rates, which when unaccounted for can lead to the under-designing of such systems. Furthermore, a new empirical prediction model for the estimation of thermal conductivity of cement-based porous sensible heat storage materials and naturally occurring crystalline rock formations as a function of temperature is proposed. The results of the model prediction are compared with the experimental results with satisfactory results.

43 CFR 418.28 - Conditions of delivery.

Code of Federal Regulations, 2010 CFR

2010-10-01

... particulars including the known or estimated location and amounts; (3) The amount will not be included as a valid headgate delivery for purposes of computing the Project efficiency and resultant incentive credit... treated directly as a debit to Lahontan storage in the same manner as an efficiency debit. (b) District...

Initial guidelines and estimates for a power system with inertial (flywheel) energy storage

NASA Technical Reports Server (NTRS)

Slifer, L. W., Jr.

1980-01-01

The starting point for the assessment of a spacecraft power system utilizing inertial (flywheel) energy storage. Both general and specific guidelines are defined for the assessment of a modular flywheel system, operationally similar to but with significantly greater capability than the multimission modular spacecraft (MMS) power system. Goals for the flywheel system are defined in terms of efficiently train estimates and mass estimates for the system components. The inertial storage power system uses a 5 kw-hr flywheel storage component at 50 percent depth of discharge (DOD). It is capable of supporting an average load of 3 kw, including a peak load of 7.5 kw for 10 percent of the duty cycle, in low earth orbit operation. The specific power goal for the system is 10 w/kg, consisting of a 56w/kg (end of life) solar array, a 21.7 w-hr/kg (at 50 percent DOD) flywheel, and 43 w/kg power processing (conditioning, control and distribution).

Estimating the value of electricity storage in PJM: Arbitrage and some welfare effects

DOE PAGES

Sioshansi, Ramteen; Denholm, Paul; Jenkin, Thomas; ...

2008-10-31

Here, significant increases in prices and price volatility of natural gas and electricity have raised interest in the potential economic opportunities for electricity storage. In this paper, we analyze the arbitrage value of a price-taking storage device in PJM during the six-year period from 2002 to 2007, to understand the impact of fuel prices, transmission constraints, efficiency, storage capacity, and fuel mix. The impact of load-shifting for larger amounts of storage, where reductions in arbitrage are offset by shifts in consumer and producer surplus as well as increases in social welfare from a variety of sources, is also considered.

Sorbent Material Property Requirements for On-Board Hydrogen Storage for Automotive Fuel Cell Systems.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Ahluwalia, R. K.; Peng, J-K; Hua, T. Q.

2015-05-25

Material properties required for on-board hydrogen storage in cryogenic sorbents for use with automotive polymer electrolyte membrane (PEM) fuel cell systems are discussed. Models are formulated for physical, thermodynamic and transport properties, and for the dynamics of H-2 refueling and discharge from a sorbent bed. A conceptual storage configuration with in-bed heat exchanger tubes, a Type-3 containment vessel, vacuum insulation and requisite balance-of-plant components is developed to determine the peak excess sorption capacity and differential enthalpy of adsorption for 5.5 wt% system gravimetric capacity and 55% well-to-tank (WTT) efficiency. The analysis also determines the bulk density to which the materialmore » must be compacted for the storage system to reach 40 g.L-1 volumetric capacity. Thermal transport properties and heat transfer enhancement methods are analyzed to estimate the material thermal conductivity needed to achieve 1.5 kg.min(-1) H-2 refueling rate. Operating temperatures and pressures are determined for 55% WTT efficiency and 95% usable H-2. Needs for further improvements in material properties are analyzed that would allow reduction of storage pressure to 50 bar from 100 bar, elevation of storage temperature to 175-200 K from 150 K, and increase of WTT efficiency to 57.5% or higher.« less

Online Updating of Statistical Inference in the Big Data Setting.

PubMed

Schifano, Elizabeth D; Wu, Jing; Wang, Chun; Yan, Jun; Chen, Ming-Hui

2016-01-01

We present statistical methods for big data arising from online analytical processing, where large amounts of data arrive in streams and require fast analysis without storage/access to the historical data. In particular, we develop iterative estimating algorithms and statistical inferences for linear models and estimating equations that update as new data arrive. These algorithms are computationally efficient, minimally storage-intensive, and allow for possible rank deficiencies in the subset design matrices due to rare-event covariates. Within the linear model setting, the proposed online-updating framework leads to predictive residual tests that can be used to assess the goodness-of-fit of the hypothesized model. We also propose a new online-updating estimator under the estimating equation setting. Theoretical properties of the goodness-of-fit tests and proposed estimators are examined in detail. In simulation studies and real data applications, our estimator compares favorably with competing approaches under the estimating equation setting.

A parameter estimation subroutine package

NASA Technical Reports Server (NTRS)

Bierman, G. J.; Nead, M. W.

1978-01-01

Linear least squares estimation and regression analyses continue to play a major role in orbit determination and related areas. A library of FORTRAN subroutines were developed to facilitate analyses of a variety of estimation problems. An easy to use, multi-purpose set of algorithms that are reasonably efficient and which use a minimal amount of computer storage are presented. Subroutine inputs, outputs, usage and listings are given, along with examples of how these routines can be used. The routines are compact and efficient and are far superior to the normal equation and Kalman filter data processing algorithms that are often used for least squares analyses.

Mars Propellant Liquefaction Modeling in Thermal Desktop

NASA Technical Reports Server (NTRS)

Desai, Pooja; Hauser, Dan; Sutherlin, Steven

2017-01-01

NASAs current Mars architectures are assuming the production and storage of 23 tons of liquid oxygen on the surface of Mars over a duration of 500+ days. In order to do this in a mass efficient manner, an energy efficient refrigeration system will be required. Based on previous analysis NASA has decided to do all liquefaction in the propulsion vehicle storage tanks. In order to allow for transient Martian environmental effects, a propellant liquefaction and storage system for a Mars Ascent Vehicle (MAV) was modeled using Thermal Desktop. The model consisted of a propellant tank containing a broad area cooling loop heat exchanger integrated with a reverse turbo Brayton cryocooler. Cryocooler sizing and performance modeling was conducted using MAV diurnal heat loads and radiator rejection temperatures predicted from a previous thermal model of the MAV. A system was also sized and modeled using an alternative heat rejection system that relies on a forced convection heat exchanger. Cryocooler mass, input power, and heat rejection for both systems were estimated and compared against sizing based on non-transient sizing estimates.

Thermodynamic analysis of a combined-cycle solar thermal power plant with manganese oxide-based thermochemical energy storage

NASA Astrophysics Data System (ADS)

Lei, Qi; Bader, Roman; Kreider, Peter; Lovegrove, Keith; Lipiński, Wojciech

2017-11-01

We explore the thermodynamic efficiency of a solar-driven combined cycle power system with manganese oxide-based thermochemical energy storage system. Manganese oxide particles are reduced during the day in an oxygen-lean atmosphere obtained with a fluidized-bed reactor at temperatures in the range of 750-1600°C using concentrated solar energy. Reduced hot particles are stored and re-oxidized during night-time to achieve continuous power plant operation. The steady-state mass and energy conservation equations are solved for all system components to calculate the thermodynamic properties and mass flow rates at all state points in the system, taking into account component irreversibilities. The net power block and overall solar-to-electric energy conversion efficiencies, and the required storage volumes for solids and gases in the storage system are predicted. Preliminary results for a system with 100 MW nominal solar power input at a solar concentration ratio of 3000, designed for constant round-the-clock operation with 8 hours of on-sun and 16 hours of off-sun operation and with manganese oxide particles cycled between 750 and 1600°C yield a net power block efficiency of 60.0% and an overall energy conversion efficiency of 41.3%. Required storage tank sizes for the solids are estimated to be approx. 5-6 times smaller than those of state-of-the-art molten salt systems.

Catchment-scale groundwater recharge and vegetation water use efficiency

NASA Astrophysics Data System (ADS)

Troch, P. A. A.; Dwivedi, R.; Liu, T.; Meira, A.; Roy, T.; Valdés-Pineda, R.; Durcik, M.; Arciniega, S.; Brena-Naranjo, J. A.

2017-12-01

Precipitation undergoes a two-step partitioning when it falls on the land surface. At the land surface and in the shallow subsurface, rainfall or snowmelt can either runoff as infiltration/saturation excess or quick subsurface flow. The rest will be stored temporarily in the root zone. From the root zone, water can leave the catchment as evapotranspiration or percolate further and recharge deep storage (e.g. fractured bedrock aquifer). Quantifying the average amount of water that recharges deep storage and sustains low flows is extremely challenging, as we lack reliable methods to quantify this flux at the catchment scale. It was recently shown, however, that for semi-arid catchments in Mexico, an index of vegetation water use efficiency, i.e. the Horton index (HI), could predict deep storage dynamics. Here we test this finding using 247 MOPEX catchments across the conterminous US, including energy-limited catchments. Our results show that the observed HI is indeed a reliable predictor of deep storage dynamics in space and time. We further investigate whether the HI can also predict average recharge rates across the conterminous US. We find that the HI can reliably predict the average recharge rate, estimated from the 50th percentile flow of the flow duration curve. Our results compare favorably with estimates of average recharge rates from the US Geological Survey. Previous research has shown that HI can be reliably estimated based on aridity index, mean slope and mean elevation of a catchment (Voepel et al., 2011). We recalibrated Voepel's model and used it to predict the HI for our 247 catchments. We then used these predicted values of the HI to estimate average recharge rates for our catchments, and compared them with those estimated from observed HI. We find that the accuracies of our predictions based on observed and predicted HI are similar. This provides an estimation method of catchment-scale average recharge rates based on easily derived catchment characteristics, such as climate and topography, and free of discharge measurements.

Modeling Pumped Thermal Energy Storage with Waste Heat Harvesting

NASA Astrophysics Data System (ADS)

Abarr, Miles L. Lindsey

This work introduces a new concept for a utility scale combined energy storage and generation system. The proposed design utilizes a pumped thermal energy storage (PTES) system, which also utilizes waste heat leaving a natural gas peaker plant. This system creates a low cost utility-scale energy storage system by leveraging this dual-functionality. This dissertation first presents a review of previous work in PTES as well as the details of the proposed integrated bottoming and energy storage system. A time-domain system model was developed in Mathworks R2016a Simscape and Simulink software to analyze this system. Validation of both the fluid state model and the thermal energy storage model are provided. The experimental results showed the average error in cumulative fluid energy between simulation and measurement was +/- 0.3% per hour. Comparison to a Finite Element Analysis (FEA) model showed <1% error for bottoming mode heat transfer. The system model was used to conduct sensitivity analysis, baseline performance, and levelized cost of energy of a recently proposed Pumped Thermal Energy Storage and Bottoming System (Bot-PTES) that uses ammonia as the working fluid. This analysis focused on the effects of hot thermal storage utilization, system pressure, and evaporator/condenser size on the system performance. This work presents the estimated performance for a proposed baseline Bot-PTES. Results of this analysis showed that all selected parameters had significant effects on efficiency, with the evaporator/condenser size having the largest effect over the selected ranges. Results for the baseline case showed stand-alone energy storage efficiencies between 51 and 66% for varying power levels and charge states, and a stand-alone bottoming efficiency of 24%. The resulting efficiencies for this case were low compared to competing technologies; however, the dual-functionality of the Bot-PTES enables it to have higher capacity factor, leading to 91-197/MWh levelized cost of energy compared to 262-284/MWh for batteries and $172-254/MWh for Compressed Air Energy Storage.

A parameter estimation subroutine package

NASA Technical Reports Server (NTRS)

Bierman, G. J.; Nead, W. M.

1977-01-01

Linear least squares estimation and regression analyses continue to play a major role in orbit determination and related areas. FORTRAN subroutines have been developed to facilitate analyses of a variety of parameter estimation problems. Easy to use multipurpose sets of algorithms are reported that are reasonably efficient and which use a minimal amount of computer storage. Subroutine inputs, outputs, usage and listings are given, along with examples of how these routines can be used.

Potential evaluation of CO2 storage and enhanced oil recovery of tight oil reservoir in the Ordos Basin, China.

PubMed

Tian, Xiaofeng; Cheng, Linsong; Cao, Renyi; Zhang, Miaoyi; Guo, Qiang; Wang, Yimin; Zhang, Jian; Cui, Yu

2015-07-01

Carbon -di-oxide (CO2) is regarded as the most important greenhouse gas to accelerate climate change and ocean acidification. The Chinese government is seeking methods to reduce anthropogenic CO2 gas emission. CO2 capture and geological storage is one of the main methods. In addition, injecting CO2 is also an effective method to replenish formation energy in developing tight oil reservoirs. However, exiting methods to estimate CO2 storage capacity are all based on the material balance theory. This was absolutely correct for normal reservoirs. However, as natural fractures widely exist in tight oil reservoirs and majority of them are vertical ones, tight oil reservoirs are not close. Therefore, material balance theory is not adaptive. In the present study, a new method to calculate CO2 storage capacity is presented. The CO2 effective storage capacity, in this new method, consisted of free CO2, CO2 dissolved in oil and CO2 dissolved in water. Case studies of tight oil reservoir from Ordos Basin was conducted and it was found that due to far lower viscosity of CO2 and larger solubility in oil, CO2 could flow in tight oil reservoirs more easily. As a result, injecting CO2 in tight oil reservoirs could obviously enhance sweep efficiency by 24.5% and oil recovery efficiency by 7.5%. CO2 effective storage capacity of Chang 7 tight oil reservoir in Longdong area was 1.88 x 10(7) t. The Chang 7 tight oil reservoir in Ordos Basin was estimated to be 6.38 x 10(11) t. As tight oil reservoirs were widely distributed in Songliao Basin, Sichuan Basin and so on, geological storage capacity of CO2 in China is potential.

Applying spectral data analysis techniques to aquifer monitoring data in Belvoir Ranch, Wyoming

NASA Astrophysics Data System (ADS)

Gao, F.; He, S.; Zhang, Y.

2017-12-01

This study uses spectral data analysis techniques to estimate the hydraulic parameters from water level fluctuation due to tide effect and barometric effect. All water level data used in this study are collected in Belvoir Ranch, Wyoming. Tide effect can be not only observed in coastal areas, but also in inland confined aquifers. The force caused by changing positions of sun and moon affects not only ocean but also solid earth. The tide effect has an oscillatory pumping or injection sequence to the aquifer, and can be observed from dense water level monitoring. Belvoir Ranch data are collected once per hour, thus is dense enough to capture the tide effect. First, transforming de-trended data from temporal domain to frequency domain with Fourier transform method. Then, the storage coefficient can be estimated using Bredehoeft-Jacob model. After this, analyze the gain function, which expresses the amplification and attenuation of the output signal, and derive barometric efficiency. Next, find effective porosity with storage coefficient and barometric efficiency with Jacob's model. Finally, estimate aquifer transmissivity and hydraulic conductivity using Paul Hsieh's method. The estimated hydraulic parameters are compared with those from traditional pumping data estimation. This study proves that hydraulic parameter can be estimated by only analyze water level data in frequency domain. It has the advantages of low cost and environmental friendly, thus should be considered for future use of hydraulic parameter estimations.

Sedimentation Survey of Lago Icacos, Puerto Rico, March 2004

USGS Publications Warehouse

Soler-López, Luis R.

2007-01-01

The Lago Icacos, a small reservoir built in 1930 and owned by the Puerto Rico Electric Power Authority, is part of the Rio Blanco Hydroelectric Power System. The reservoir is located in Naguabo, within the Caribbean National Forest in eastern Puerto Rico. The original storage capacity of the reservoir was 19,119 cubic meters in 1930. The bathymetric survey conducted by the U.S. Geological Survey in March 2004 indicates a storage capacity of 7,435 cubic meters or 39 percent of the original storage capacity, and a maximum depth of 5.3 meters. The reservoir has been dredged several times to restore lost storage capacity caused by high sediment loads and the frequent landslides that occur upstream from the dam, which have partially or completely filled the Lago Icacos. Because sediment removal activities have not been documented, sedimentation rates could not be determined using storage volume comparisons. A reservoir sedimentation rate was calculated using the daily sediment load data gathered at the U.S. Geological Survey Rio Icacos streamflow station upstream of the reservoir, the estimated Lago Icacos sediment trapping efficiency, and the estimated sediment yield of the Lago Icacos basin extrapolated from the Rio Icacos sediment load data. Using these properties, the Lago Icacos sedimentation rate was estimated as 71 cubic meters per year, equivalent to about 1 percent of the original storage capacity per year. The Lago Icacos 7.47-square-kilometer drainage area sediment yield was estimated as 7,126 tonnes per year or about 954 tonnes per square kilometer per year. Based on the current estimated sedimentation rate of 71 cubic meters per year, Lago Icacos has a useful life of about 105 years or to year 2109.

Effects of May through July 2015 storm events on suspended sediment loads, sediment trapping efficiency, and storage capacity of John Redmond Reservoir, east-central Kansas

USGS Publications Warehouse

Foster, Guy M.

2016-06-20

The U.S. Geological Survey, in cooperation with the Kansas Water Office, computed the suspended-sediment inflows and retention in John Redmond Reservoir during May through July 2015. Computations relied upon previously published turbidity-suspended sediment relations at water-quality monitoring sites located upstream and downstream from the reservoir. During the 3-month period, approximately 872,000 tons of sediment entered the reservoir, and 57,000 tons were released through the reservoir outlet. The average monthly trapping efficiency during this period was 93 percent, and monthly averages ranged from 83 to 97 percent. During the study period, an estimated 980 acre-feet of storage was lost, over 2.4 times the design annual sedimentation rate of the reservoir. Storm inflows during the 3-month analysis period reduced reservoir storage in the conservation pool approximately 1.6 percent. This indicates that large inflows, coupled with minimal releases, can have substantial effects on reservoir storage and lifespan.

Supercritical CO2 Power Cycles: Design Considerations for Concentrating Solar Power

DOE Office of Scientific and Technical Information (OSTI.GOV)

Neises, Ty; Turchi, Craig

2014-09-01

A comparison of three supercritical CO2 Brayton cycles: the simple cycle, recompression cycle and partial-cooling cycle indicates the partial-cooling cycle is favored for use in concentrating solar power (CSP) systems. Although it displays slightly lower cycle efficiency versus the recompression cycle, the partial-cooling cycle is estimated to have lower total recuperator size, as well as a lower maximum s-CO2 temperature in the high-temperature recuperator. Both of these effects reduce recuperator cost. Furthermore, the partial-cooling cycle provides a larger temperature differential across the turbine, which translates into a smaller, more cost-effective thermal energy storage system. The temperature drop across the turbinemore » (and by extension, across a thermal storage system) for the partial-cooling cycle is estimated to be 23% to 35% larger compared to the recompression cycle of equal recuperator conductance between 5 and 15 MW/K. This reduces the size and cost of the thermal storage system. Simulations by NREL and Abengoa Solar indicate the partial-cooling cycle results in a lower LCOE compared with the recompression cycle, despite the former's slightly lower cycle efficiency. Advantages of the recompression cycle include higher thermal efficiency and potential for a smaller precooler. The overall impact favors the use of a partial-cooling cycle for CSP compared to the more commonly analyzed recompression cycle.« less

Geological Carbon Sequestration Storage Resource Estimates for the Ordovician St. Peter Sandstone, Illinois and Michigan Basins, USA

DOE Office of Scientific and Technical Information (OSTI.GOV)

Barnes, David; Ellett, Kevin; Leetaru, Hannes

The Cambro-Ordovician strata of the Midwest of the United States is a primary target for potential geological storage of CO2 in deep saline formations. The objective of this project is to develop a comprehensive evaluation of the Cambro-Ordovician strata in the Illinois and Michigan Basins above the basal Mount Simon Sandstone since the Mount Simon is the subject of other investigations including a demonstration-scale injection at the Illinois Basin Decatur Project. The primary reservoir targets investigated in this study are the middle Ordovician St Peter Sandstone and the late Cambrian to early Ordovician Knox Group carbonates. The topic of thismore » report is a regional-scale evaluation of the geologic storage resource potential of the St Peter Sandstone in both the Illinois and Michigan Basins. Multiple deterministic-based approaches were used in conjunction with the probabilistic-based storage efficiency factors published in the DOE methodology to estimate the carbon storage resource of the formation. Extensive data sets of core analyses and wireline logs were compiled to develop the necessary inputs for volumetric calculations. Results demonstrate how the range in uncertainty of storage resource estimates varies as a function of data availability and quality, and the underlying assumptions used in the different approaches. In the simplest approach, storage resource estimates were calculated from mapping the gross thickness of the formation and applying a single estimate of the effective mean porosity of the formation. Results from this approach led to storage resource estimates ranging from 3.3 to 35.1 Gt in the Michigan Basin, and 1.0 to 11.0 Gt in the Illinois Basin at the P10 and P90 probability level, respectively. The second approach involved consideration of the diagenetic history of the formation throughout the two basins and used depth-dependent functions of porosity to derive a more realistic spatially variable model of porosity rather than applying a single estimate of porosity throughout the entire potential reservoir domains. The second approach resulted in storage resource estimates of 3.0 to 31.6 Gt in the Michigan Basin, and 0.6 to 6.1 Gt in the Illinois Basin. The third approach attempted to account for the local-scale variability in reservoir quality as a function of both porosity and permeability by using core and log analyses to calculate explicitly the net effective porosity at multiple well locations, and interpolate those results throughout the two basins. This approach resulted in storage resource estimates of 10.7 to 34.7 Gt in the Michigan Basin, and 11.2 to 36.4 Gt in the Illinois Basin. A final approach used advanced reservoir characterization as the most sophisticated means to estimating storage resource by defining reservoir properties for multiple facies within the St Peter formation. This approach was limited to the Michigan Basin since the Illinois Basin data set did not have the requisite level of data quality and sampling density to support such an analysis. Results from this approach led to storage resource estimates of 15.4 Gt to 50.1 Gt for the Michigan Basin. The observed variability in results from the four different approaches is evaluated in the context of data and methodological constraints, leading to the conclusion that the storage resource estimates from the first two approaches may be conservative, whereas the net porosity based approaches may over-estimate the resource.« less

Application of Electron-Beam Controlled Diffuse Discharges to Fast Switching

DTIC Science & Technology

1983-06-01

pressure , switch area and length are estimated self-consistently for a given system efficiency is reviewed, The formalism is used to design a single pulse, 200 kV, 30 kA (6 omega) , 100 ns FWHM inductive storage generator.

An efficient deterministic-probabilistic approach to modeling regional groundwater flow: 1. Theory

USGS Publications Warehouse

Yen, Chung-Cheng; Guymon, Gary L.

1990-01-01

An efficient probabilistic model is developed and cascaded with a deterministic model for predicting water table elevations in regional aquifers. The objective is to quantify model uncertainty where precise estimates of water table elevations may be required. The probabilistic model is based on the two-point probability method which only requires prior knowledge of uncertain variables mean and coefficient of variation. The two-point estimate method is theoretically developed and compared with the Monte Carlo simulation method. The results of comparisons using hypothetical determinisitic problems indicate that the two-point estimate method is only generally valid for linear problems where the coefficients of variation of uncertain parameters (for example, storage coefficient and hydraulic conductivity) is small. The two-point estimate method may be applied to slightly nonlinear problems with good results, provided coefficients of variation are small. In such cases, the two-point estimate method is much more efficient than the Monte Carlo method provided the number of uncertain variables is less than eight.

An Efficient Deterministic-Probabilistic Approach to Modeling Regional Groundwater Flow: 1. Theory

NASA Astrophysics Data System (ADS)

Yen, Chung-Cheng; Guymon, Gary L.

1990-07-01

An efficient probabilistic model is developed and cascaded with a deterministic model for predicting water table elevations in regional aquifers. The objective is to quantify model uncertainty where precise estimates of water table elevations may be required. The probabilistic model is based on the two-point probability method which only requires prior knowledge of uncertain variables mean and coefficient of variation. The two-point estimate method is theoretically developed and compared with the Monte Carlo simulation method. The results of comparisons using hypothetical determinisitic problems indicate that the two-point estimate method is only generally valid for linear problems where the coefficients of variation of uncertain parameters (for example, storage coefficient and hydraulic conductivity) is small. The two-point estimate method may be applied to slightly nonlinear problems with good results, provided coefficients of variation are small. In such cases, the two-point estimate method is much more efficient than the Monte Carlo method provided the number of uncertain variables is less than eight.

Leveraging social system networks in ubiquitous high-data-rate health systems.

PubMed

Massey, Tammara; Marfia, Gustavo; Stoelting, Adam; Tomasi, Riccardo; Spirito, Maurizio A; Sarrafzadeh, Majid; Pau, Giovanni

2011-05-01

Social system networks with high data rates and limited storage will discard data if the system cannot connect and upload the data to a central server. We address the challenge of limited storage capacity in mobile health systems during network partitions with a heuristic that achieves efficiency in storage capacity by modifying the granularity of the medical data during long intercontact periods. Patterns in the connectivity, reception rate, distance, and location are extracted from the social system network and leveraged in the global algorithm and online heuristic. In the global algorithm, the stochastic nature of the data is modeled with maximum likelihood estimation based on the distribution of the reception rates. In the online heuristic, the correlation between system position and the reception rate is combined with patterns in human mobility to estimate the intracontact and intercontact time. The online heuristic performs well with a low data loss of 2.1%-6.1%.

Motor-cognitive dual-task performance: effects of a concurrent motor task on distinct components of visual processing capacity.

PubMed

Künstler, E C S; Finke, K; Günther, A; Klingner, C; Witte, O; Bublak, P

2018-01-01

Dual tasking, or the simultaneous execution of two continuous tasks, is frequently associated with a performance decline that can be explained within a capacity sharing framework. In this study, we assessed the effects of a concurrent motor task on the efficiency of visual information uptake based on the 'theory of visual attention' (TVA). TVA provides parameter estimates reflecting distinct components of visual processing capacity: perceptual threshold, visual processing speed, and visual short-term memory (VSTM) storage capacity. Moreover, goodness-of-fit values and bootstrapping estimates were derived to test whether the TVA-model is validly applicable also under dual task conditions, and whether the robustness of parameter estimates is comparable in single- and dual-task conditions. 24 subjects of middle to higher age performed a continuous tapping task, and a visual processing task (whole report of briefly presented letter arrays) under both single- and dual-task conditions. Results suggest a decline of both visual processing capacity and VSTM storage capacity under dual-task conditions, while the perceptual threshold remained unaffected by a concurrent motor task. In addition, goodness-of-fit values and bootstrapping estimates support the notion that participants processed the visual task in a qualitatively comparable, although quantitatively less efficient way under dual-task conditions. The results support a capacity sharing account of motor-cognitive dual tasking and suggest that even performing a relatively simple motor task relies on central attentional capacity that is necessary for efficient visual information uptake.

Energy storage arbitrage under day-ahead and real-time price uncertainty

DOE Office of Scientific and Technical Information (OSTI.GOV)

Krishnamurthy, Dheepak; Uckun, Canan; Zhou, Zhi

Electricity markets must match real-time supply and demand of electricity. With increasing penetration of renewable resources, it is important that this balancing is done effectively, considering the high uncertainty of wind and solar energy. Storing electrical energy can make the grid more reliable and efficient and energy storage is proposed as a complement to highly variable renewable energy sources. However, for investments in energy storage to increase, participating in the market must become economically viable for owners. This paper proposes a stochastic formulation of a storage owner’s arbitrage profit maximization problem under uncertainty in day-ahead (DA) and real-time (RT) marketmore » prices. The proposed model helps storage owners in market bidding and operational decisions and in estimation of the economic viability of energy storage. Finally, case study results on realistic market price data show that the novel stochastic bidding approach does significantly better than the deterministic benchmark.« less

Energy storage arbitrage under day-ahead and real-time price uncertainty

DOE PAGES

Krishnamurthy, Dheepak; Uckun, Canan; Zhou, Zhi; ...

2017-04-04

Electricity markets must match real-time supply and demand of electricity. With increasing penetration of renewable resources, it is important that this balancing is done effectively, considering the high uncertainty of wind and solar energy. Storing electrical energy can make the grid more reliable and efficient and energy storage is proposed as a complement to highly variable renewable energy sources. However, for investments in energy storage to increase, participating in the market must become economically viable for owners. This paper proposes a stochastic formulation of a storage owner’s arbitrage profit maximization problem under uncertainty in day-ahead (DA) and real-time (RT) marketmore » prices. The proposed model helps storage owners in market bidding and operational decisions and in estimation of the economic viability of energy storage. Finally, case study results on realistic market price data show that the novel stochastic bidding approach does significantly better than the deterministic benchmark.« less

Efficient Storage Scheme of Covariance Matrix during Inverse Modeling

NASA Astrophysics Data System (ADS)

Mao, D.; Yeh, T. J.

2013-12-01

During stochastic inverse modeling, the covariance matrix of geostatistical based methods carries the information about the geologic structure. Its update during iterations reflects the decrease of uncertainty with the incorporation of observed data. For large scale problem, its storage and update cost too much memory and computational resources. In this study, we propose a new efficient storage scheme for storage and update. Compressed Sparse Column (CSC) format is utilized to storage the covariance matrix, and users can assign how many data they prefer to store based on correlation scales since the data beyond several correlation scales are usually not very informative for inverse modeling. After every iteration, only the diagonal terms of the covariance matrix are updated. The off diagonal terms are calculated and updated based on shortened correlation scales with a pre-assigned exponential model. The correlation scales are shortened by a coefficient, i.e. 0.95, every iteration to show the decrease of uncertainty. There is no universal coefficient for all the problems and users are encouraged to try several times. This new scheme is tested with 1D examples first. The estimated results and uncertainty are compared with the traditional full storage method. In the end, a large scale numerical model is utilized to validate this new scheme.

Using the nonlinear aquifer storage-discharge relationship to simulate the base flow of glacier- and snowmelt-dominated basins in northwest China

NASA Astrophysics Data System (ADS)

Gan, R.; Luo, Y.

2013-09-01

Base flow is an important component in hydrological modeling. This process is usually modeled by using the linear aquifer storage-discharge relation approach, although the outflow from groundwater aquifers is nonlinear. To identify the accuracy of base flow estimates in rivers dominated by snowmelt and/or glacier melt in arid and cold northwestern China, a nonlinear storage-discharge relationship for use in SWAT (Soil Water Assessment Tool) modeling was developed and applied to the Manas River basin in the Tian Shan Mountains. Linear reservoir models and a digital filter program were used for comparisons. Meanwhile, numerical analysis of recession curves from 78 river gauge stations revealed variation in the parameters of the nonlinear relationship. It was found that the nonlinear reservoir model can improve the streamflow simulation, especially for low-flow period. The higher Nash-Sutcliffe efficiency, logarithmic efficiency, and volumetric efficiency, and lower percent bias were obtained when compared to the one-linear reservoir approach. The parameter b of the aquifer storage-discharge function varied mostly between 0.0 and 0.1, which is much smaller than the suggested value of 0.5. The coefficient a of the function is related to catchment properties, primarily the basin and glacier areas.

Prospective CO 2 saline resource estimation methodology: Refinement of existing US-DOE-NETL methods based on data availability

DOE PAGES

Goodman, Angela; Sanguinito, Sean; Levine, Jonathan S.

2016-09-28

Carbon storage resource estimation in subsurface saline formations plays an important role in establishing the scale of carbon capture and storage activities for governmental policy and commercial project decision-making. Prospective CO 2 resource estimation of large regions or subregions, such as a basin, occurs at the initial screening stages of a project using only limited publicly available geophysical data, i.e. prior to project-specific site selection data generation. As the scale of investigation is narrowed and selected areas and formations are identified, prospective CO 2 resource estimation can be refined and uncertainty narrowed when site-specific geophysical data are available. Here, wemore » refine the United States Department of Energy – National Energy Technology Laboratory (US-DOE-NETL) methodology as the scale of investigation is narrowed from very large regional assessments down to selected areas and formations that may be developed for commercial storage. In addition, we present a new notation that explicitly identifies differences between data availability and data sources used for geologic parameters and efficiency factors as the scale of investigation is narrowed. This CO 2 resource estimation method is available for screening formations in a tool called CO 2-SCREEN.« less

Prospective CO 2 saline resource estimation methodology: Refinement of existing US-DOE-NETL methods based on data availability

DOE Office of Scientific and Technical Information (OSTI.GOV)

Goodman, Angela; Sanguinito, Sean; Levine, Jonathan S.

Carbon storage resource estimation in subsurface saline formations plays an important role in establishing the scale of carbon capture and storage activities for governmental policy and commercial project decision-making. Prospective CO 2 resource estimation of large regions or subregions, such as a basin, occurs at the initial screening stages of a project using only limited publicly available geophysical data, i.e. prior to project-specific site selection data generation. As the scale of investigation is narrowed and selected areas and formations are identified, prospective CO 2 resource estimation can be refined and uncertainty narrowed when site-specific geophysical data are available. Here, wemore » refine the United States Department of Energy – National Energy Technology Laboratory (US-DOE-NETL) methodology as the scale of investigation is narrowed from very large regional assessments down to selected areas and formations that may be developed for commercial storage. In addition, we present a new notation that explicitly identifies differences between data availability and data sources used for geologic parameters and efficiency factors as the scale of investigation is narrowed. This CO 2 resource estimation method is available for screening formations in a tool called CO 2-SCREEN.« less

Efficient Approaches for Propagating Hydrologic Forcing Uncertainty: High-Resolution Applications Over the Western United States

NASA Astrophysics Data System (ADS)

Hobbs, J.; Turmon, M.; David, C. H.; Reager, J. T., II; Famiglietti, J. S.

2017-12-01

NASA's Western States Water Mission (WSWM) combines remote sensing of the terrestrial water cycle with hydrological models to provide high-resolution state estimates for multiple variables. The effort includes both land surface and river routing models that are subject to several sources of uncertainty, including errors in the model forcing and model structural uncertainty. Computational and storage constraints prohibit extensive ensemble simulations, so this work outlines efficient but flexible approaches for estimating and reporting uncertainty. Calibrated by remote sensing and in situ data where available, we illustrate the application of these techniques in producing state estimates with associated uncertainties at kilometer-scale resolution for key variables such as soil moisture, groundwater, and streamflow.

Microfluidic study for investigating migration and residual phenomena of supercritical CO2 in porous media

NASA Astrophysics Data System (ADS)

Park, Gyuryeong; Wang, Sookyun; Lee, Minhee; Um, Jeong-Gi; Kim, Seon-Ok

2017-04-01

The storage of CO2 in underground geological formation such as deep saline aquifers or depleted oil and gas reservoirs is one of the most promising technologies for reducing the atmospheric CO2 release. The processes in geological CO2 storage involves injection of supercritical CO2 (scCO2) into porous formations saturated with brine and initiates CO2 flooding with immiscible displacement. The CO2 migration and porewater displacement within geological formations, and , consequentially, the storage efficiency are governed by the interaction of fluid and rock properties and are affected by the interfacial tension, capillarity, and wettability in supercritical CO2-brine-mineral systems. This study aims to observe the displacement pattern and estimate storage efficiency by using micromodels. This study aims to conduct scCO2 injection experiments for visualization of distribution of injected scCO2 and residual porewater in transparent pore networks on microfluidic chips under high pressure and high temperature conditions. In order to quantitatively analyze the porewater displacement by scCO2 injection under geological CO2 storage conditions, the images of invasion patterns and distribution of CO2 in the pore network are acquired through a imaging system with a microscope. The results from image analysis were applied in quantitatively investigating the effects of major environmental factors and scCO2 injection methods on porewater displacement process by scCO2 and storage efficiency. The experimental observation results could provide important fundamental information on capillary characteristics of reservoirs and improve our understanding of CO2 sequestration progress.

On the Capacity of Attention: Its Estimation and Its Role in Working Memory and Cognitive Aptitudes

PubMed Central

Cowan, Nelson; Elliott, Emily M.; Saults, J. Scott; Morey, Candice C.; Mattox, Sam; Hismjatullina, Anna; Conway, Andrew R.A.

2008-01-01

Working memory (WM) is the set of mental processes holding limited information in a temporarily accessible state in service of cognition. We provide a theoretical framework to understand the relation between WM and aptitude measures. The WM measures that have yielded high correlations with aptitudes include separate storage and processing task components, on the assumption that WM involves both storage and processing. We argue that the critical aspect of successful WM measures is that rehearsal and grouping processes are prevented, allowing a clearer estimate of how many separate chunks of information the focus of attention circumscribes at once. Storage-and-processing tasks correlate with aptitudes, according to this view, largely because the processing task prevents rehearsal and grouping of items to be recalled. In a developmental study, we document that several scope-of-attention measures that do not include a separate processing component, but nevertheless prevent efficient rehearsal or grouping, also correlate well with aptitudes and with storage-and-processing measures. So does digit span in children too young to rehearse. PMID:16039935

Offshore Storage Resource Assessment - Final Scientific/Technical Report

DOE Office of Scientific and Technical Information (OSTI.GOV)

Savage, Bill; Ozgen, Chet

The DOE developed volumetric equation for estimating Prospective Resources (CO 2 storage) in oil and gas reservoirs was utilized on each depleted field in the Federal GOM. This required assessment of the in-situ hydrocarbon fluid volumes for the fields under evaluation in order to apply the DOE equation. This project utilized public data from the U.S. Department of the Interior, Bureau of Ocean Energy Management (BOEM) Reserves database and from a well reputed, large database (250,000+ wells) of GOM well and production data marketed by IHS, Inc. IHS interpreted structure map files were also accessed for a limited number ofmore » fields. The databases were used along with geological and petrophysical software to identify depleted oil and gas fields in the Federal GOM region. BOEM arranged for access by the project team to proprietary reservoir level maps under an NDA. Review of the BOEM’s Reserves database as of December 31, 2013 indicated that 675 fields in the region were depleted. NITEC identified and rank these 675 fields containing 3,514 individual reservoirs based on BOEM’s estimated OOIP or OGIP values available in the Reserves database. The estimated BOEM OOIP or OGIP values for five fields were validated by an independent evaluation using available petrophysical, geologic and engineering data in the databases. Once this validation was successfully completed, the BOEM ranked list was used to calculate the estimated CO 2 storage volume for each field/reservoir using the DOE CO 2 Resource Estimate Equation. This calculation assumed a range for the CO 2 efficiency factor in the equation, as it was not known at that point in time. NITEC then utilize reservoir simulation to further enhance and refine the DOE equation estimated range of CO 2 storage volumes. NITEC used a purpose built, publically available, 4-component, compositional reservoir simulator developed under funding from DOE (DE-FE0006015) to assess CO 2-EOR and CO 2 storage in 73 fields/461 reservoirs. This simulator was fast and easy to utilize and provided a valuable enhanced assessment and refinement of the estimated CO 2 storage volume for each reservoir simulated. The user interface was expanded to allow for calculation of a probability based assessment of the CO 2 storage volume based on typical uncertainties in operating conditions and reservoir properties during the CO 2 injection period. This modeling of the CO 2 storage estimates for the simulated reservoirs resulted in definition of correlations applicable to all reservoir types (a refined DOE equation) which can be used for predictive purposes using available public data. Application of the correlations to the 675 depleted fields yielded a total CO 2 storage capacity of 4,748 MM tons. The CO 2 storage assessments were supplemented with simulation modeling of eleven (11) oil reservoirs that quantified the change in the stored CO 2 storage volume with the addition of CO 2-EOR (Enhanced Oil Recovery) production. Application of CO 2-EOR to oil reservoirs resulted in higher volumes of CO 2 storage.« less

U.S. DOE NETL methodology for estimating the prospective CO 2 storage resource of shales at the national and regional scale

DOE Office of Scientific and Technical Information (OSTI.GOV)

Levine, Jonathan S.; Fukai, Isis; Soeder, Daniel J.

While the majority of shale formations will serve as reservoir seals for stored anthropogenic carbon dioxide (CO2), hydrocarbon-bearing shale formations may be potential geologic sinks after depletion through primary production. Here in this paper we present the United States-Department of Energy-National Energy Technology Laboratory (US-DOE-NETL) methodology for screening-level assessment of prospective CO 2 storage resources in shale using a volumetric equation. Volumetric resource estimates are produced from the bulk volume, porosity, and sorptivity of the shale and storage efficiency factors based on formation-scale properties and petrophysical limitations on fluid transport. Prospective shale formations require: (1) prior hydrocarbon production using horizontalmore » drilling and stimulation via staged, high-volume hydraulic fracturing, (2) depths sufficient to maintain CO 2 in a supercritical state, generally >800 m, and (3) an overlying seal. The US-DOE-NETL methodology accounts for storage of CO 2 in shale as a free fluid phase within fractures and matrix pores and as an sorbed phase on organic matter and clays. Uncertainties include but are not limited to poorly-constrained geologic variability in formation thickness, porosity, existing fluid content, organic richness, and mineralogy. Knowledge of how these parameters may be linked to depositional environments, facies, and diagenetic history of the shale will improve the understanding of pore-to-reservoir scale behavior, and provide improved estimates of prospective CO 2 storage.« less

U.S. DOE NETL methodology for estimating the prospective CO 2 storage resource of shales at the national and regional scale

DOE PAGES

Levine, Jonathan S.; Fukai, Isis; Soeder, Daniel J.; ...

2016-05-31

While the majority of shale formations will serve as reservoir seals for stored anthropogenic carbon dioxide (CO2), hydrocarbon-bearing shale formations may be potential geologic sinks after depletion through primary production. Here in this paper we present the United States-Department of Energy-National Energy Technology Laboratory (US-DOE-NETL) methodology for screening-level assessment of prospective CO 2 storage resources in shale using a volumetric equation. Volumetric resource estimates are produced from the bulk volume, porosity, and sorptivity of the shale and storage efficiency factors based on formation-scale properties and petrophysical limitations on fluid transport. Prospective shale formations require: (1) prior hydrocarbon production using horizontalmore » drilling and stimulation via staged, high-volume hydraulic fracturing, (2) depths sufficient to maintain CO 2 in a supercritical state, generally >800 m, and (3) an overlying seal. The US-DOE-NETL methodology accounts for storage of CO 2 in shale as a free fluid phase within fractures and matrix pores and as an sorbed phase on organic matter and clays. Uncertainties include but are not limited to poorly-constrained geologic variability in formation thickness, porosity, existing fluid content, organic richness, and mineralogy. Knowledge of how these parameters may be linked to depositional environments, facies, and diagenetic history of the shale will improve the understanding of pore-to-reservoir scale behavior, and provide improved estimates of prospective CO 2 storage.« less

Cubic-panorama image dataset analysis for storage and transmission

NASA Astrophysics Data System (ADS)

Salehi, Saeed; Dubois, Eric

2013-02-01

In this paper we address the problem of disparity estimation required for free navigation in acquired cubicpanorama image datasets. A client server based scheme is assumed and a remote user is assumed to seek information at each navigation step. The initial compression of such image datasets for storage as well as the transmission of the required data is addressed in this work. Regarding the compression of such data for storage, a fast method that uses properties of the epipolar geometry together with the cubic format of panoramas is used to estimate disparity vectors efficiently. Assuming the use of B pictures, the concept of forward and backward prediction is addressed. Regarding the transmission stage, a new disparity vector transcoding-like scheme is introduced and a frame conversion scenario is addressed. Details on how to pick the best vector among candidate disparity vectors is explained. In all the above mentioned cases, results are compared both visually through error images as well as using the objective measure of Peak Signal to Noise Ratio (PSNR) versus time.

The mechanics of explosive seed dispersal in orange jewelweed (Impatiens capensis)

PubMed Central

Hayashi, Marika; Feilich, Kara L.; Ellerby, David J.

2009-01-01

Explosive dehiscence ballistically disperses seeds in a number of plant species. During dehiscence, mechanical energy stored in specialized tissues is transferred to the seeds to increase their kinetic and potential energies. The resulting seed dispersal patterns have been investigated in some ballistic dispersers, but the mechanical performance of a launch mechanism of this type has not been measured. The properties of the energy storage tissue and the energy transfer efficiency of the launch mechanism were quantified in Impatiens capensis. In this species the valves forming the seed pod wall store mechanical energy. Their mass specific energy storage capacity (124 J kg−1) was comparable with that of elastin and spring steel. The energy storage capacity of the pod tissues was determined by their level of hydration, suggesting a role for turgor pressure in the energy storage mechanism. During dehiscence the valves coiled inwards, collapsing the pod and ejecting the seeds. Dehiscence took 4.2±0.4 ms (mean ±SEM, n=13). The estimated efficiency with which energy was transferred to the seeds was low (0.51±0.26%, mean ±SEM, n=13). The mean seed launch angle (17.4±5.2, mean ±SEM, n=45) fell within the range predicted by a ballistic model to maximize dispersal distance. Low ballistic dispersal efficiency or effectiveness may be characteristic of species that also utilize secondary seed dispersal mechanisms. PMID:19321647

The mechanics of explosive seed dispersal in orange jewelweed (Impatiens capensis).

PubMed

Hayashi, Marika; Feilich, Kara L; Ellerby, David J

2009-01-01

Explosive dehiscence ballistically disperses seeds in a number of plant species. During dehiscence, mechanical energy stored in specialized tissues is transferred to the seeds to increase their kinetic and potential energies. The resulting seed dispersal patterns have been investigated in some ballistic dispersers, but the mechanical performance of a launch mechanism of this type has not been measured. The properties of the energy storage tissue and the energy transfer efficiency of the launch mechanism were quantified in Impatiens capensis. In this species the valves forming the seed pod wall store mechanical energy. Their mass specific energy storage capacity (124 J kg(-1)) was comparable with that of elastin and spring steel. The energy storage capacity of the pod tissues was determined by their level of hydration, suggesting a role for turgor pressure in the energy storage mechanism. During dehiscence the valves coiled inwards, collapsing the pod and ejecting the seeds. Dehiscence took 4.2+/-0.4 ms (mean +/-SEM, n=13). The estimated efficiency with which energy was transferred to the seeds was low (0.51+/-0.26%, mean +/-SEM, n=13). The mean seed launch angle (17.4+/-5.2, mean +/-SEM, n=45) fell within the range predicted by a ballistic model to maximize dispersal distance. Low ballistic dispersal efficiency or effectiveness may be characteristic of species that also utilize secondary seed dispersal mechanisms.

Reasoning and memory: People make varied use of the information available in working memory.

PubMed

Hardman, Kyle O; Cowan, Nelson

2016-05-01

Working memory (WM) is used for storing information in a highly accessible state so that other mental processes, such as reasoning, can use that information. Some WM tasks require that participants not only store information, but also reason about that information to perform optimally on the task. In this study, we used visual WM tasks that had both storage and reasoning components to determine both how ideally people are able to reason about information in WM and if there is a relationship between information storage and reasoning. We developed novel psychological process models of the tasks that allowed us to estimate for each participant both how much information they had in WM and how efficiently they reasoned about that information. Our estimates of information use showed that participants are not all ideal information users or minimal information users, but rather that there are individual differences in the thoroughness of information use in our WM tasks. However, we found that our participants tended to be more ideal than minimal. One implication of this work is that to accurately estimate the amount of information in WM, it is important to also estimate how efficiently that information is used. This new analysis contributes to the theoretical premise that human rationality may be bounded by the complexity of task demands. (PsycINFO Database Record (c) 2016 APA, all rights reserved).

Reasoning and memory: People make varied use of the information available in working memory

PubMed Central

Hardman, Kyle O.; Cowan, Nelson

2015-01-01

Working memory (WM) is used for storing information in a highly-accessible state so that other mental processes, such as reasoning, can use that information. Some WM tasks require that participants not only store information, but also reason about that information in order to perform optimally on the task. In this study, we used visual WM tasks that had both storage and reasoning components in order to determine both how ideally people are able to reason about information in WM and if there is a relationship between information storage and reasoning. We developed novel psychological process models of the tasks that allowed us to estimate for each participant both how much information they had in WM and how efficiently they reasoned about that information. Our estimates of information use showed that participants are not all ideal information users or minimal information users, but rather that there are individual differences in the thoroughness of information use in our WM tasks. However, we found that our participants tended to be more ideal than minimal. One implication of this work is that in order to accurately estimate the amount of information in WM, it is important to also estimate how efficiently that information is used. This new analysis contributes to the theoretical premise that human rationality may be bounded by the complexity of task demands. PMID:26569436

Novel Molten Salts Thermal Energy Storage for Concentrating Solar Power Generation

DOE Office of Scientific and Technical Information (OSTI.GOV)

Reddy, Ramana G.

2013-10-23

The explicit UA program objective is to develop low melting point (LMP) molten salt thermal energy storage media with high thermal energy storage density for sensible heat storage systems. The novel Low Melting Point (LMP) molten salts are targeted to have the following characteristics: 1. Lower melting point (MP) compared to current salts (<222ºC) 2. Higher energy density compared to current salts (>300 MJ/m3) 3. Lower power generation cost compared to current salt In terms of lower power costs, the program target the DOE's Solar Energy Technologies Program year 2020 goal to create systems that have the potential to reducemore » the cost of Thermal Energy Storage (TES) to less than $15/kWh-th and achieve round trip efficiencies greater than 93%. The project has completed the experimental investigations to determine the thermo-physical, long term thermal stability properties of the LMP molten salts and also corrosion studies of stainless steel in the candidate LMP molten salts. Heat transfer and fluid dynamics modeling have been conducted to identify heat transfer geometry and relative costs for TES systems that would utilize the primary LMP molten salt candidates. The project also proposes heat transfer geometry with relevant modifications to suit the usage of our molten salts as thermal energy storage and heat transfer fluids. The essential properties of the down-selected novel LMP molten salts to be considered for thermal storage in solar energy applications were experimentally determined, including melting point, heat capacity, thermal stability, density, viscosity, thermal conductivity, vapor pressure, and corrosion resistance of SS 316. The thermodynamic modeling was conducted to determine potential high temperature stable molten salt mixtures that have thermal stability up to 1000 °C. The thermo-physical properties of select potential high temperature stable (HMP) molten salt mixtures were also experimentally determined. All the salt mixtures align with the go/no-go goals stipulated by the DOE for this project. Energy densities of all salt mixtures were higher than that of the current solar salt. The salt mixtures costs have been estimated and TES system costs for a 2 tank, direct approach have been estimated for each of these materials. All estimated costs are significantly below the baseline system that used solar salt. These lower melt point salts offer significantly higher energy density per volume than solar salt – and therefore attractively smaller inventory and equipment costs. Moreover, a new TES system geometry has been recommended A variety of approaches were evaluated to use the low melting point molten salt. Two novel changes are recommended that 1) use the salt as a HTF through the solar trough field, and 2) use the salt to not only create steam but also to preheat the condensed feedwater for Rankine cycle. The two changes enable the powerblock to operate at 500°C, rather than the current 400°C obtainable using oil as the HTF. Secondly, the use of salt to preheat the feedwater eliminates the need to extract steam from the low pressure turbine for that purpose. Together, these changes result in a dramatic 63% reduction required for 6 hour salt inventory, a 72% reduction in storage volume, and a 24% reduction in steam flow rate in the power block. Round trip efficiency for the Case 5 - 2 tank “direct” system is estimated at >97%, with only small losses from time under storage and heat exchange, and meeting RFP goals. This attractive efficiency is available because the major heat loss experienced in a 2 tank “indirect” system - losses by transferring the thermal energy from oil HTF to the salt storage material and back to oil to run the steam generator at night - is not present for the 2 tank direct system. The higher heat capacity values for both LMP and HMP systems enable larger storage capacities for concentrating solar power.« less

Subsurface storage of freshwater in South Florida; a digital analysis of recoverability

USGS Publications Warehouse

Merritt, Michael L.

1983-01-01

As part of a feasibility study of cyclic freshwater injection, digital models were implemented to analyze the relation of recovery efficiency to various hydrogeologic conditions which could prevail in brackish aquifers and to various management regimes. The analyses implemented an approach in which the control for sensitivity testing was a hypothetical aquifer representative of potential injection zones in south Florida, and parameter variations in sensitivity tests represented possible variations in aquifer conditions in the area. The permeability of the aquifer determined whether buoyancy stratification could reduce recovery efficiency. The range of permeability leading to buoyancy stratification became lower as resident fluid salinity increased. Thus, recovery efficiency was optimized by both low permeability and low resident fluid density. High levels of simulated hydrodynamic dispersion led to the lowest estimates of recovery efficiency. Advection by regional flow within the artesian injection zone could significantly affect recovery efficiency, depending upon the storage period, the volume injected, and site-specific hydraulic characteristics. Recovery efficiency was unrelated to the rate of injection or withdrawal or to the degree of penetration of permeable layers, and improved with successive cycles of injection and recovery. (USGS)

Analysis of recovery efficiency in high-temperature aquifer thermal energy storage: a Rayleigh-based method

NASA Astrophysics Data System (ADS)

Schout, Gilian; Drijver, Benno; Gutierrez-Neri, Mariene; Schotting, Ruud

2014-01-01

High-temperature aquifer thermal energy storage (HT-ATES) is an important technique for energy conservation. A controlling factor for the economic feasibility of HT-ATES is the recovery efficiency. Due to the effects of density-driven flow (free convection), HT-ATES systems applied in permeable aquifers typically have lower recovery efficiencies than conventional (low-temperature) ATES systems. For a reliable estimation of the recovery efficiency it is, therefore, important to take the effect of density-driven flow into account. A numerical evaluation of the prime factors influencing the recovery efficiency of HT-ATES systems is presented. Sensitivity runs evaluating the effects of aquifer properties, as well as operational variables, were performed to deduce the most important factors that control the recovery efficiency. A correlation was found between the dimensionless Rayleigh number (a measure of the relative strength of free convection) and the calculated recovery efficiencies. Based on a modified Rayleigh number, two simple analytical solutions are proposed to calculate the recovery efficiency, each one covering a different range of aquifer thicknesses. The analytical solutions accurately reproduce all numerically modeled scenarios with an average error of less than 3 %. The proposed method can be of practical use when considering or designing an HT-ATES system.

Evaluation of annual efficiencies of high temperature central receiver concentrated solar power plants with thermal energy storage.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Ehrhart, Brian David; Gill, David Dennis

The current study has examined four cases of a central receiver concentrated solar power plant with thermal energy storage using the DELSOL and SOLERGY computer codes. The current state-of-the-art base case was compared with a theoretical high temperature case which was based on the scaling of some input parameters and the estimation of other parameters based on performance targets from the Department of Energy SunShot Initiative. This comparison was done for both current and high temperature cases in two configurations: a surround field with an external cylindrical receiver and a north field with a single cavity receiver. There is amore » fairly dramatic difference between the design point and annual average performance, especially in the solar field and receiver subsystems, and also in energy losses due to the thermal energy storage being full to capacity. Additionally, there are relatively small differences (<2%) in annual average efficiencies between the Base and High Temperature cases, despite an increase in thermal to electric conversion efficiency of over 8%. This is due the increased thermal losses at higher temperature and operational losses due to subsystem start-up and shut-down. Thermal energy storage can mitigate some of these losses by utilizing larger thermal energy storage to ensure that the electric power production system does not need to stop and re-start as often, but solar energy is inherently transient. Economic and cost considerations were not considered here, but will have a significant impact on solar thermal electric power production strategy and sizing.« less

Biotechnological storage and utilization of entrapped solar energy.

PubMed

Bhattacharya, Sumana; Schiavone, Marc; Nayak, Amiya; Bhattacharya, Sanjoy K

2005-03-01

Our laboratory has recently developed a device employing immobilized F0F1 adenosine triphosphatase (ATPase) that allows synthesis of adenosine triphosphate (ATP) from adenosine 5'-diphosphate and inorganic phosphate using solar energy. We present estimates of total solar energy received by Earth's land area and demonstrate that its efficient capture may allow conversion of solar energy and storage into bonds of biochemicals using devices harboring either immobilized ATPase or NADH dehydrogenase. Capture and storage of solar energy into biochemicals may also enable fixation of CO2 emanating from polluting units. The cofactors ATP and NADH synthesized using solar energy could be used for regeneration of acceptor D-ribulose-1,5-bisphosphate from 3-phosphoglycerate formed during CO2 fixation.

Power and efficiency of insect flight muscle.

PubMed

Ellington, C P

1985-03-01

The efficiency and mechanical power output of insect flight muscle have been estimated from a study of hovering flight. The maximum power output, calculated from the muscle properties, is adequate for the aerodynamic power requirements. However, the power output is insufficient to oscillate the wing mass as well unless there is good elastic storage of the inertial energy, and this is consistent with reports of elastic components in the flight system. A comparison of the mechanical power output with the metabolic power input to the flight muscles suggests that the muscle efficiency is quite low: less than 10%.

Energy efficiency evaluation of a stationary lithium-ion battery container storage system via electro-thermal modeling and detailed component analysis

DOE PAGES

Schimpe, Michael; Naumann, Maik; Truong, Nam; ...

2017-11-08

Energy efficiency is a key performance indicator for battery storage systems. A detailed electro-thermal model of a stationary lithium-ion battery system is developed and an evaluation of its energy efficiency is conducted. The model offers a holistic approach to calculating conversion losses and auxiliary power consumption. Sub-models for battery rack, power electronics, thermal management as well as the control and monitoring components are developed and coupled to a comprehensive model. The simulation is parametrized based on a prototype 192 kWh system using lithium iron phosphate batteries connected to the low voltage grid. The key loss mechanisms are identified, thoroughly analyzedmore » and modeled. Generic profiles featuring various system operation modes are evaluated to show the characteristics of stationary battery systems. Typically the losses in the power electronics outweigh the losses in the battery at low power operating points. The auxiliary power consumption dominates for low system utilization rates. For estimation of real-world performance, the grid applications Primary Control Reserve, Secondary Control Reserve and the storage of surplus photovoltaic power are evaluated. Conversion round-trip efficiency is in the range of 70-80%. Finally, overall system efficiency, which also considers system power consumption, is 8-13 percentage points lower for Primary Control Reserve and the photovoltaic-battery application. However, for Secondary Control Reserve, the total round-trip efficiency is found to be extremely low at 23% due to the low energy throughput of this application type.« less

Energy efficiency evaluation of a stationary lithium-ion battery container storage system via electro-thermal modeling and detailed component analysis

DOE Office of Scientific and Technical Information (OSTI.GOV)

Schimpe, Michael; Naumann, Maik; Truong, Nam

Energy efficiency is a key performance indicator for battery storage systems. A detailed electro-thermal model of a stationary lithium-ion battery system is developed and an evaluation of its energy efficiency is conducted. The model offers a holistic approach to calculating conversion losses and auxiliary power consumption. Sub-models for battery rack, power electronics, thermal management as well as the control and monitoring components are developed and coupled to a comprehensive model. The simulation is parametrized based on a prototype 192 kWh system using lithium iron phosphate batteries connected to the low voltage grid. The key loss mechanisms are identified, thoroughly analyzedmore » and modeled. Generic profiles featuring various system operation modes are evaluated to show the characteristics of stationary battery systems. Typically the losses in the power electronics outweigh the losses in the battery at low power operating points. The auxiliary power consumption dominates for low system utilization rates. For estimation of real-world performance, the grid applications Primary Control Reserve, Secondary Control Reserve and the storage of surplus photovoltaic power are evaluated. Conversion round-trip efficiency is in the range of 70-80%. Finally, overall system efficiency, which also considers system power consumption, is 8-13 percentage points lower for Primary Control Reserve and the photovoltaic-battery application. However, for Secondary Control Reserve, the total round-trip efficiency is found to be extremely low at 23% due to the low energy throughput of this application type.« less

Performance evaluation of molten salt thermal storage systems

NASA Astrophysics Data System (ADS)

Kolb, G. J.; Nikolai, U.

1987-09-01

The molton salt thermal storage system located at the Central Receiver Test Facility (CRTF) was recently subjected to thermal performance tests. The system is composed of a hot storage tank containing molten nitrate salt at a temperature of 1050 F and a cold tank containing 550 F salt with associated valves and controls. It is rated at 7 MWht and was designed and installed by Martin Marietta Corporation in 1982. The results of these tests were used to accomplish four objectives: (1) to compare the current thermal performance of the system with the performance of the system soon after it was installed, (2) to validate a dynamic computer model of the system, (3) to obtain an estimate of an annual system efficiency for a hypothetical commercial scale 1200 MWht system and (4) to compare the performance of the CRTF system with thermal storage systems developed by the European solar community.

Charge Transfer Inefficiency in Pinned Photodiode CMOS image sensors: Simple Montecarlo modeling and experimental measurement based on a pulsed storage-gate method

NASA Astrophysics Data System (ADS)

Pelamatti, Alice; Goiffon, Vincent; Chabane, Aziouz; Magnan, Pierre; Virmontois, Cédric; Saint-Pé, Olivier; de Boisanger, Michel Breart

2016-11-01

The charge transfer time represents the bottleneck in terms of temporal resolution in Pinned Photodiode (PPD) CMOS image sensors. This work focuses on the modeling and estimation of this key parameter. A simple numerical model of charge transfer in PPDs is presented. The model is based on a Montecarlo simulation and takes into account both charge diffusion in the PPD and the effect of potential obstacles along the charge transfer path. This work also presents a new experimental approach for the estimation of the charge transfer time, called pulsed Storage Gate (SG) method. This method, which allows reproduction of a ;worst-case; transfer condition, is based on dedicated SG pixel structures and is particularly suitable to compare transfer efficiency performances for different pixel geometries.

The Cancer Genomics Hub (CGHub): overcoming cancer through the power of torrential data

PubMed Central

Wilks, Christopher; Cline, Melissa S.; Weiler, Erich; Diehkans, Mark; Craft, Brian; Martin, Christy; Murphy, Daniel; Pierce, Howdy; Black, John; Nelson, Donavan; Litzinger, Brian; Hatton, Thomas; Maltbie, Lori; Ainsworth, Michael; Allen, Patrick; Rosewood, Linda; Mitchell, Elizabeth; Smith, Bradley; Warner, Jim; Groboske, John; Telc, Haifang; Wilson, Daniel; Sanford, Brian; Schmidt, Hannes; Haussler, David; Maltbie, Daniel

2014-01-01

The Cancer Genomics Hub (CGHub) is the online repository of the sequencing programs of the National Cancer Institute (NCI), including The Cancer Genomics Atlas (TCGA), the Cancer Cell Line Encyclopedia (CCLE) and the Therapeutically Applicable Research to Generate Effective Treatments (TARGET) projects, with data from 25 different types of cancer. The CGHub currently contains >1.4 PB of data, has grown at an average rate of 50 TB a month and serves >100 TB per week. The architecture of CGHub is designed to support bulk searching and downloading through a Web-accessible application programming interface, enforce patient genome confidentiality in data storage and transmission and optimize for efficiency in access and transfer. In this article, we describe the design of these three components, present performance results for our transfer protocol, GeneTorrent, and finally report on the growth of the system in terms of data stored and transferred, including estimated limits on the current architecture. Our experienced-based estimates suggest that centralizing storage and computational resources is more efficient than wide distribution across many satellite labs. Database URL: https://cghub.ucsc.edu PMID:25267794

A parameter estimation subroutine package

NASA Technical Reports Server (NTRS)

Bierman, G. J.; Nead, M. W.

1978-01-01

Linear least squares estimation and regression analyses continue to play a major role in orbit determination and related areas. In this report we document a library of FORTRAN subroutines that have been developed to facilitate analyses of a variety of estimation problems. Our purpose is to present an easy to use, multi-purpose set of algorithms that are reasonably efficient and which use a minimal amount of computer storage. Subroutine inputs, outputs, usage and listings are given along with examples of how these routines can be used. The following outline indicates the scope of this report: Section (1) introduction with reference to background material; Section (2) examples and applications; Section (3) subroutine directory summary; Section (4) the subroutine directory user description with input, output, and usage explained; and Section (5) subroutine FORTRAN listings. The routines are compact and efficient and are far superior to the normal equation and Kalman filter data processing algorithms that are often used for least squares analyses.

Assessing efficiency and economic viability of rainwater harvesting systems for meeting non-potable water demands in four climatic zones of China

NASA Astrophysics Data System (ADS)

Zhang, S.; Jing, X.

2017-12-01

Rainwater harvesting is now increasingly used to manage urban flood and alleviate water scarcity crisis. In this study, a computational tool based on water balance equation is developed to assess stormwater capture and water saving efficiency and economic viability of rainwater harvesting systems (RHS) in eight cities across four climatic zones of China. It requires daily rainfall, contributing area, runoff losses, first flush volume, storage capacity, daily water demand and economic parameters as inputs. Three non-potable water demand scenarios (i.e., toilet flushing, lawn irrigation, and combination of them) are considered. The water demand for lawn irrigation is estimated using the Cropwat 8.0 and Climwat 2.0. Results indicate that higher water saving efficiency and water supply time reliability can be achieved for RHS with larger storage capacities, for lower water demand scenarios and located in more humid regions, while higher stormwater capture efficiency is associated with larger storage capacity, higher water demand scenarios and less rainfall. For instance, a 40 m3 RHS in Shanghai (humid climate) for lawn irrigation can capture 17% of stormwater, while its water saving efficiency and time reliability can reach 96 % and 98%, respectively. The water saving efficiency and time reliability of a 20 m3 RHS in Xining (semi-arid climate) for toilet flushing are 19% and 16%, respectively, but it can capture 63% of stormwater. With the current values of economic parameters, economic viability of RHS can be achieved in humid and semi-humid regions for reasonably designed RHS; however, it is not financially viable to install RHS in arid regions as the benefit-cost ratio is much smaller than 1.0.

Performance and cost of energy transport and storage systems for dish applications using reversible chemical reactions

NASA Technical Reports Server (NTRS)

Schredder, J. M.; Fujita, T.

1984-01-01

The use of reversible chemical reactions for energy transport and storage for parabolic dish networks is considered. Performance and cost characteristics are estimated for systems using three reactions (sulfur-trioxide decomposition, steam reforming of methane, and carbon-dioxide reforming of methane). Systems are considered with and without storage, and in several energy-delivery configurations that give different profiles of energy delivered versus temperature. Cost estimates are derived assuming the use of metal components and of advanced ceramics. (The latter reduces the costs by three- to five-fold). The process that led to the selection of the three reactions is described, and the effects of varying temperatures, pressures, and heat exchanger sizes are addressed. A state-of-the-art survey was performed as part of this study. As a result of this survey, it appears that formidable technical risks exist for any attempt to implement the systems analyzed in this study, especially in the area of reactor design and performance. The behavior of all components and complete systems under thermal energy transients is very poorly understood. This study indicates that thermochemical storage systems that store reactants as liquids have efficiencies below 60%, which is in agreement with the findings of earlier investigators.

Cost and performance model for redox flow batteries

NASA Astrophysics Data System (ADS)

Viswanathan, Vilayanur; Crawford, Alasdair; Stephenson, David; Kim, Soowhan; Wang, Wei; Li, Bin; Coffey, Greg; Thomsen, Ed; Graff, Gordon; Balducci, Patrick; Kintner-Meyer, Michael; Sprenkle, Vincent

2014-02-01

A cost model is developed for all vanadium and iron-vanadium redox flow batteries. Electrochemical performance modeling is done to estimate stack performance at various power densities as a function of state of charge and operating conditions. This is supplemented with a shunt current model and a pumping loss model to estimate actual system efficiency. The operating parameters such as power density, flow rates and design parameters such as electrode aspect ratio and flow frame channel dimensions are adjusted to maximize efficiency and minimize capital costs. Detailed cost estimates are obtained from various vendors to calculate cost estimates for present, near-term and optimistic scenarios. The most cost-effective chemistries with optimum operating conditions for power or energy intensive applications are determined, providing a roadmap for battery management systems development for redox flow batteries. The main drivers for cost reduction for various chemistries are identified as a function of the energy to power ratio of the storage system. Levelized cost analysis further guide suitability of various chemistries for different applications.

Techno-economic performance evaluation of solar tower plants with integrated multi-layered PCM thermocline thermal energy storage - A comparative study to conventional two-tank storage systems

NASA Astrophysics Data System (ADS)

Guedéz, Rafael; Ferruzza, Davide; Arnaudo, Monica; Rodríguez, Ivette; Perez-Segarra, Carlos D.; Hassar, Zhor; Laumert, Björn

2016-05-01

Solar Tower Power Plants with thermal energy storage are a promising technology for dispatchable renewable energy in the near future. Storage integration makes possible to shift the electricity production to more profitable peak hours. Usually two tanks are used to store cold and hot fluids, but this means both higher investment costs and difficulties during the operation of the variable volume tanks. Instead, another solution can be a single tank thermocline storage in a multi-layered configuration. In such tank both latent and sensible fillers are employed to decrease the related cost up to 30% and maintain high efficiencies. This paper analyses a multi-layered solid PCM storage tank concept for solar tower applications, and describes a comprehensive methodology to determine under which market structures such devices can outperform the more conventional two tank storage systems. A detail model of the tank has been developed and introduced in an existing techno-economic tool developed by the authors (DYESOPT). The results show that under current cost estimates and technical limitations the multi-layered solid PCM storage concept is a better solution when peaking operating strategies are desired, as it is the case for the two-tier South African tariff scheme.

High Carbon Use Efficiency is Not Explained by Production of Storage Compounds

NASA Astrophysics Data System (ADS)

Dijkstra, Paul; van Groenigen, Kees-Jan

2015-04-01

The efficiency with which microbes use substrate to make new microbial biomass (Carbon Use Efficiency or CUE; mol C / mol C) is an important variable in soil and ecosystem C cycling models. Estimates of CUE in soil microbial communities vary widely. It has been hypothesized that high values of CUE are associated with production of storage compounds following a sudden increases in substrate availability during CUE measurements. In that case, these high CUE values would not be representative for balanced microbial growth (i.e. the production of all compounds needed to make new microbial cells). To test this hypothesis, we added position-specific 13C-labeled glucose isotopomers in parallel incubations of a ponderosa pine and piñon-juniper soil. We compared the measured pattern of CO2 release for the six glucose C atoms with patterns of CO2 production expected for balanced growth with a low, medium, or high CUE, and with CO2 production patterns associated with production of storage compounds (glycogen, lipids, or polyhydroxybutyrate). The measured position-specific CO2 production did not match that for production of glycogen, lipids, or polyhydroxybutyrate, but agreed closely with that expected for balanced growth at high CUE and high pentose phosphate pathway activity. We conclude that soil microbial communities utilize glucose substrate for biomass growth with high CUE, and that addition of small amounts of 13C-labeled glucose tracers do not affect CUE or induce storage compounds production. We submit that the measurement of position-specific CO2 production offers a quick and easy way to test biochemically explicit hypotheses concerning microbial growth metabolism.

Carbon nanomaterials for advanced energy conversion and storage.

PubMed

Dai, Liming; Chang, Dong Wook; Baek, Jong-Beom; Lu, Wen

2012-04-23

It is estimated that the world will need to double its energy supply by 2050. Nanotechnology has opened up new frontiers in materials science and engineering to meet this challenge by creating new materials, particularly carbon nanomaterials, for efficient energy conversion and storage. Comparing to conventional energy materials, carbon nanomaterials possess unique size-/surface-dependent (e.g., morphological, electrical, optical, and mechanical) properties useful for enhancing the energy-conversion and storage performances. During the past 25 years or so, therefore, considerable efforts have been made to utilize the unique properties of carbon nanomaterials, including fullerenes, carbon nanotubes, and graphene, as energy materials, and tremendous progress has been achieved in developing high-performance energy conversion (e.g., solar cells and fuel cells) and storage (e.g., supercapacitors and batteries) devices. This article reviews progress in the research and development of carbon nanomaterials during the past twenty years or so for advanced energy conversion and storage, along with some discussions on challenges and perspectives in this exciting field. Copyright © 2012 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

A Conceptual Design Study on the Application of Liquid Metal Heat Transfer Technology to the Solar Thermal Power Plant

NASA Technical Reports Server (NTRS)

Zimmerman, W. F.; Robertson, C. S.; Ehde, C. L.; Divakaruni, S. M.; Stacy, L. E.

1979-01-01

Alkali metal heat transfer technology was used in the development of conceptual designs for the transport and storage of sensible and latent heat thermal energy in distributed concentrator, solar Stirling power conversion systems at a power level of 15 kWe per unit. Both liquid metal pumped loop and heat pipe thermal transport were considered; system configurations included: (1) an integrated, focal mounted sodium heat pipe solar receiver (HPSR) with latent heat thermal energy storage; (2) a liquid sodium pumped loop with the latent heat storage, Stirling engine-generator, pump and valves located on the back side of the concentrator; and (3) similar pumped loops serving several concentrators with more centralized power conversion and storage. The focus mounted HPSR was most efficient, lightest and lowest in estimated cost. Design confirmation testing indicated satisfactory performance at all angles of inclination of the primary heat pipes to be used in the solar receiver.

Identifying the best locations to install flow control devices in sewer networks to enable in-sewer storage

NASA Astrophysics Data System (ADS)

Leitão, J. P.; Carbajal, J. P.; Rieckermann, J.; Simões, N. E.; Sá Marques, A.; de Sousa, L. M.

2018-01-01

The activation of available in-sewer storage volume has been suggested as a low-cost flood and combined sewer overflow mitigation measure. However, it is currently unknown what the attributes for suitable objective functions to identify the best location for flow control devices are and the impact of those attributes on the results. In this study, we present a novel location model and efficient algorithm to identify the best location(s) to install flow limiters. The model is a screening tool that does not require hydraulic simulations but rather considers steady state instead of simplistic static flow conditions. It also maximises in-sewer storage according to different reward functions that also considers the potential impact of flow control device failure. We demonstrate its usefulness on two real sewer networks, for which an in-sewer storage potential of approximately 2,000 m3 and 500 m3 was estimated with five flow control devices installed.

Optical storage with electromagnetically induced transparency in cold atoms at a high optical depth

NASA Astrophysics Data System (ADS)

Zhang, Shanchao; Zhou, Shuyu; Liu, Chang; Chen, J. F.; Wen, Jianming; Loy, M. M. T.; Wong, G. K. L.; Du, Shengwang

2012-06-01

We report experimental demonstration of efficient optical storage with electromagnetically induced transparency (EIT) in a dense cold ^85Rb atomic ensemble trapped in a two-dimensional magneto-optical trap. By varying the optical depth (OD) from 0 to 140, we observe that the optimal storage efficiency for coherent optical pulses has a saturation value of 50% as OD > 50. Our result is consistent with that obtained from hot vapor cell experiments which suggest that a four-wave mixing nonlinear process degrades the EIT storage coherence and efficiency. We apply this EIT quantum memory for narrow-band single photons with controllable waveforms, and obtain an optimal storage efficiency of 49±3% for single-photon wave packets. This is the highest single-photon storage efficiency reported up to today and brings the EIT atomic quantum memory close to practical application because an efficiency of above 50% is necessary to operate the memory within non-cloning regime and beat the classical limit.

Changes in antioxidant and biochemical activities in castor oil-coated Capsicum annuum L. during postharvest storage.

PubMed

Panigrahi, Jitendriya; Patel, Mansi; Patel, Niyati; Gheewala, Bhumi; Gantait, Saikat

2018-06-01

This study, for the first time, evaluates the efficiency of castor oil when used as an external coating on Capsicum annuum L., to increase postharvest storage-life at 4 ± 1 °C. The castor oil-coated fruits were successfully stored for 36 days, while the non-coated fruits could only sustain for 18 days. Throughout the storage period (at 9-day intervals), different antioxidants and biochemical assays (allied with storage) such as titratable acidity, ascorbic acid content, ferrous ion chelating activity, reducing power, DPPH scavenging activity, hydroxyl radical scavenging activity, total phenolic content, total sugar estimation, and enzymatic study of polyphenol oxidase and pectate lyase, were assessed. During storage, the castor oil-coated fruits showed a substantial decrease in titratable acidity, ascorbic acid content, total phenolic content, including antioxidant activities such as reducing power and DPPH activity; however, an increase in ferrous ion chelating activity, total soluble sugar content, polyphenol oxidase activity and initial pectate lyase activity was observed, in contrast to that of the non-coated fruits. The application of castor oil proved to be effective in delaying the ripening process of fruits during storage.

Uncertainty Quantification of Medium-Term Heat Storage From Short-Term Geophysical Experiments Using Bayesian Evidential Learning

NASA Astrophysics Data System (ADS)

Hermans, Thomas; Nguyen, Frédéric; Klepikova, Maria; Dassargues, Alain; Caers, Jef

2018-04-01

In theory, aquifer thermal energy storage (ATES) systems can recover in winter the heat stored in the aquifer during summer to increase the energy efficiency of the system. In practice, the energy efficiency is often lower than expected from simulations due to spatial heterogeneity of hydraulic properties or non-favorable hydrogeological conditions. A proper design of ATES systems should therefore consider the uncertainty of the prediction related to those parameters. We use a novel framework called Bayesian Evidential Learning (BEL) to estimate the heat storage capacity of an alluvial aquifer using a heat tracing experiment. BEL is based on two main stages: pre- and postfield data acquisition. Before data acquisition, Monte Carlo simulations and global sensitivity analysis are used to assess the information content of the data to reduce the uncertainty of the prediction. After data acquisition, prior falsification and machine learning based on the same Monte Carlo are used to directly assess uncertainty on key prediction variables from observations. The result is a full quantification of the posterior distribution of the prediction conditioned to observed data, without any explicit full model inversion. We demonstrate the methodology in field conditions and validate the framework using independent measurements.

Soil Moisture or Groundwater?

NASA Astrophysics Data System (ADS)

Swenson, S. C.; Lawrence, D. M.

2017-12-01

Partitioning the vertically integrated water storage variations estimated from GRACE satellite data into the components of which it is comprised requires independent information. Land surface models, which simulate the transfer and storage of moisture and energy at the land surface, are often used to estimate water storage variability of snow, surface water, and soil moisture. To obtain an estimate of changes in groundwater, the estimates of these storage components are removed from GRACE data. Biases in the modeled water storage components are therefore present in the residual groundwater estimate. In this study, we examine how soil moisture variability, estimated using the Community Land Model (CLM), depends on the vertical structure of the model. We then explore the implications of this uncertainty in the context of estimating groundwater variations using GRACE data.

Estimating the relative contributions of human withdrawals and climate variability to changes in groundwater

NASA Astrophysics Data System (ADS)

Swenson, S. C.; Lawrence, D. M.

2014-12-01

Estimating the relative contributions of human withdrawals and climate variability to changes in groundwater is a challenging task at present. One method that has been used recently is a model-data synthesis combining GRACE total water storage estimates with simulated water storage estimates from land surface models. In this method, water storage changes due to natural climate variations simulated by a model are removed from total water storage changes observed by GRACE; the residual is then interpreted as anthropogenic groundwater change. If the modeled water storage estimate contains systematic errors, these errors will also be present in the residual groundwater estimate. For example, simulations performed with the Community Land Model (CLM; the land component of the Community Earth System Model) generally show a weak (as much as 50% smaller) seasonal cycle of water storage in semi-arid regions when compared to GRACE satellite water storage estimates. This bias propagates into GRACE-CLM anthropogenic groundwater change estimates, which then exhibit unphysical seasonal variability. The CLM bias can be traced to the parameterization of soil evaporative resistance. Incorporating a new soil resistance parameterization in CLM greatly reduces the seasonal bias with respect to GRACE. In this study, we compare the improved CLM water storage estimates to GRACE and discuss the implications for estimates of anthropogenic groundwater withdrawal, showing examples for the Middle East and Southwestern United States.

Performance Study of Salt Cavern Air Storage Based Non-Supplementary Fired Compressed Air Energy Storage System

NASA Astrophysics Data System (ADS)

Chen, Xiaotao; Song, Jie; Liang, Lixiao; Si, Yang; Wang, Le; Xue, Xiaodai

2017-10-01

Large-scale energy storage system (ESS) plays an important role in the planning and operation of smart grid and energy internet. Compressed air energy storage (CAES) is one of promising large-scale energy storage techniques. However, the high cost of the storage of compressed air and the low capacity remain to be solved. This paper proposes a novel non-supplementary fired compressed air energy storage system (NSF-CAES) based on salt cavern air storage to address the issues of air storage and the efficiency of CAES. Operating mechanisms of the proposed NSF-CAES are analysed based on thermodynamics principle. Key factors which has impact on the system storage efficiency are thoroughly explored. The energy storage efficiency of the proposed NSF-CAES system can be improved by reducing the maximum working pressure of the salt cavern and improving inlet air pressure of the turbine. Simulation results show that the electric-to-electric conversion efficiency of the proposed NSF-CAES can reach 63.29% with a maximum salt cavern working pressure of 9.5 MPa and 9 MPa inlet air pressure of the turbine, which is higher than the current commercial CAES plants.

Emittance measurements in low energy ion storage rings

NASA Astrophysics Data System (ADS)

Hunt, J. R.; Carli, C.; Resta-López, J.; Welsch, C. P.

2018-07-01

The development of the next generation of ultra-low energy antiproton and ion facilities requires precise information about the beam emittance to guarantee optimum performance. In the Extra-Low ENergy Antiproton storage ring (ELENA) the transverse emittances will be measured by scraping. However, this diagnostic measurement faces several challenges: non-zero dispersion, non-Gaussian beam distributions due to effects of the electron cooler and various systematic errors such as closed orbit offsets and inaccurate rms momentum spread estimation. In addition, diffusion processes, such as intra-beam scattering might lead to emittance overestimates. Here, we present algorithms to efficiently address the emittance reconstruction in presence of the above effects, and present simulation results for the case of ELENA.

Ice Thermal Storage Systems for LWR Supplemental Cooling and Peak Power Shifting

DOE Office of Scientific and Technical Information (OSTI.GOV)

Haihua Zhao; Hongbin Zhang; Phil Sharpe

2010-06-01

Availability of enough cooling water has been one of the major issues for the nuclear power plant site selection. Cooling water issues have frequently disrupted the normal operation at some nuclear power plants during heat waves and long draught. The issues become more severe due to the new round of nuclear power expansion and global warming. During hot summer days, cooling water leaving a power plant may become too hot to threaten aquatic life so that environmental regulations may force the plant to reduce power output or even temporarily to be shutdown. For new nuclear power plants to be builtmore » at areas without enough cooling water, dry cooling can be used to remove waste heat directly into the atmosphere. However, dry cooling will result in much lower thermal efficiency when the weather is hot. One potential solution for the above mentioned issues is to use ice thermal storage systems (ITS) that reduce cooling water requirements and boost the plant’s thermal efficiency in hot hours. ITS uses cheap off-peak electricity to make ice and uses those ice for supplemental cooling during peak demand time. ITS is suitable for supplemental cooling storage due to its very high energy storage density. ITS also provides a way to shift large amount of electricity from off peak time to peak time. Some gas turbine plants already use ITS to increase thermal efficiency during peak hours in summer. ITSs have also been widely used for building cooling to save energy cost. Among three cooling methods for LWR applications: once-through, wet cooling tower, and dry cooling tower, once-through cooling plants near a large water body like an ocean or a large lake and wet cooling plants can maintain the designed turbine backpressure (or condensation temperature) during 99% of the time; therefore, adding ITS to those plants will not generate large benefits. For once-through cooling plants near a limited water body like a river or a small lake, adding ITS can bring significant economic benefits and avoid forced derating and shutdown during extremely hot weather. For the new plants using dry cooling towers, adding the ice thermal storage systems can effectively reduce the efficiency loss and water consumption during hot weather so that new LWRs could be considered in regions without enough cooling water. \\ This paper presents the feasibility study of using ice thermal storage systems for LWR supplemental cooling and peak power shifting. LWR cooling issues and ITS application status will be reviewed. Two ITS application case studies will be presented and compared with alternative options: one for once-through cooling without enough cooling for short time, and the other with dry cooling. Because capital cost, especially the ice storage structure/building cost, is the major cost for ITS, two different cost estimation models are developed: one based on scaling method, and the other based on a preliminary design using Building Information Modeling (BIM), an emerging technology in Architecture/Engineering/Construction, which enables design options, performance analysis and cost estimating in the early design stage.« less

The Cancer Genomics Hub (CGHub): overcoming cancer through the power of torrential data.

PubMed

Wilks, Christopher; Cline, Melissa S; Weiler, Erich; Diehkans, Mark; Craft, Brian; Martin, Christy; Murphy, Daniel; Pierce, Howdy; Black, John; Nelson, Donavan; Litzinger, Brian; Hatton, Thomas; Maltbie, Lori; Ainsworth, Michael; Allen, Patrick; Rosewood, Linda; Mitchell, Elizabeth; Smith, Bradley; Warner, Jim; Groboske, John; Telc, Haifang; Wilson, Daniel; Sanford, Brian; Schmidt, Hannes; Haussler, David; Maltbie, Daniel

2014-01-01

The Cancer Genomics Hub (CGHub) is the online repository of the sequencing programs of the National Cancer Institute (NCI), including The Cancer Genomics Atlas (TCGA), the Cancer Cell Line Encyclopedia (CCLE) and the Therapeutically Applicable Research to Generate Effective Treatments (TARGET) projects, with data from 25 different types of cancer. The CGHub currently contains >1.4 PB of data, has grown at an average rate of 50 TB a month and serves >100 TB per week. The architecture of CGHub is designed to support bulk searching and downloading through a Web-accessible application programming interface, enforce patient genome confidentiality in data storage and transmission and optimize for efficiency in access and transfer. In this article, we describe the design of these three components, present performance results for our transfer protocol, GeneTorrent, and finally report on the growth of the system in terms of data stored and transferred, including estimated limits on the current architecture. Our experienced-based estimates suggest that centralizing storage and computational resources is more efficient than wide distribution across many satellite labs. Database URL: https://cghub.ucsc.edu. Published by Oxford University Press 2014. This work is written by US Government employees and is in the public domain in the US.

Remote Sensing of Groundwater Storage Changes in Illinois using the Gravity Recovery and Climate Experiment (GRACE)

NASA Technical Reports Server (NTRS)

Yeh, Pat J.-F.; Swenson, S. C.; Famiglietti, J. S.; Rodell, M.

2007-01-01

Regional groundwater storage changes in Illinois are estimated from monthly GRACE total water storage change (TWSC) data and in situ measurements of soil moisture for the period 2002-2005. Groundwater storage change estimates are compared to those derived from the soil moisture and available well level data. The seasonal pattern and amplitude of GRACE-estimated groundwater storage changes track those of the in situ measurements reasonably well, although substantial differences exist in month-to-month variations. The seasonal cycle of GRACE TWSC agrees well with observations (correlation coefficient = 0.83), while the seasonal cycle of GRACE-based estimates of groundwater storage changes beneath 2 m depth agrees with observations with a correlation coefficient of 0.63. We conclude that the GRACE-based method of estimating monthly to seasonal groundwater storage changes performs reasonably well at the 200,000 sq km scale of Illinois.

SEBAL Model Using to Estimate Irrigation Water Efficiency & Water Requirement of Alfalfa Crop

NASA Astrophysics Data System (ADS)

Zeyliger, Anatoly; Ermolaeva, Olga

2013-04-01

The sustainability of irrigation is a complex and comprehensive undertaking, requiring an attention to much more than hydraulics, chemistry, and agronomy. A special combination of human, environmental, and economic factors exists in each irrigated region and must be recognized and evaluated. A way to evaluate the efficiency of irrigation water use for crop production is to consider the so-called crop-water production functions, which express the relation between the yield of a crop and the quantity of water applied to it or consumed by it. The term has been used in a somewhat ambiguous way. Some authors have defined the Crop-Water Production Functions between yield and the total amount of water applied, whereas others have defined it as a relation between yield and seasonal evapotranspiration (ET). In case of high efficiency of irrigation water use the volume of water applied is less than the potential evapotranspiration (PET), then - assuming no significant change of soil moisture storage from beginning of the growing season to its end-the volume of water may be roughly equal to ET. In other case of low efficiency of irrigation water use the volume of water applied exceeds PET, then the excess of volume of water applied over PET must go to either augmenting soil moisture storage (end-of-season moisture being greater than start-of-season soil moisture) or to runoff or/and deep percolation beyond the root zone. In presented contribution some results of a case study of estimation of biomass and leaf area index (LAI) for irrigated alfalfa by SEBAL algorithm will be discussed. The field study was conducted with aim to compare ground biomass of alfalfa at some irrigated fields (provided by agricultural farm) at Saratov and Volgograd Regions of Russia. The study was conducted during vegetation period of 2012 from April till September. All the operations from importing the data to calculation of the output data were carried by eLEAF company and uploaded in Fieldlook web geo database and used for experiment program managment. Quite good agreement between measured and calculated biomass and LAI were obtained. Estimation of effectiveness of water efficiency as well as estimation of applied water losses were done in the base of supplied irrigation water provided by local operating irrigation water supply companies and data of soil moisture monitoring. Following analyse of the remote sensing use to estimate of crop water requirement will be presented. ACKNOWLEDGMENTS. This study was financially supported by G2G project

Simulation of subsurface storage and recovery of treated effluent injected in a saline aquifer, St. Petersburg, Florida

USGS Publications Warehouse

Yobbi, D.K.

1996-01-01

The potential for subsurface storage and recovery of treated effluent into the uppermost producing zone (zone A) of the Upper Floridan aquifer in St. Petersburg, Florida, is being studied by the U.S. Geological Survey, in cooperation with the city of St. Petersburg and the Southwest Florida Water Management District. A measure of the success of this practice is the recovery efficiency, or the quantity of water relative to the quantity injected, that can be recovered before the water that is withdrawn fails to meet water-quality standards. The feasibility of this practice will depend upon the ability of the injected zone to receive, store, and discharge the injected fluid. A cylindrical model of ground-water flow and solute transport, incorporating available data on aquifer properties and water quality, was developed to determine the relation of recovery efficiency to various aquifer and fluid properties that could prevail in the study area. The reference case for testing was a base model considered representative of the saline aquifer underlying St. Petersburg. Parameter variations in the tests represent possible variations in aquifer conditions in the area. The model also was used to study the effect of various cyclic injection and withdrawal schemes on the recovery efficiency of the well and aquifer system. A base simulation assuming 15 days of injection of effluent at a rate of 1.0 million gallons per day and 15 days of withdrawal at a rate of 1.0 million gallons per day was used as reference to compare changes in various hydraulic and chemical parameters on recovery efficiency. A recovery efficiency of 20 percent was estimated for the base simulation. For practical ranges of hydraulic and fluid properties that could prevail in the study area, the model analysis indicates that (1) the greater the density contrast between injected and resident formation water, the lower the recovery efficiency, (2) recovery efficiency decreases significantly as dispersion increases, (3) high formation permeability favors low recovery efficiencies, and (4) porosity and anisotropy have little effect on recovery efficiencies. In several hypothetical tests, the recovery efficiency fluctuated between about 4 and 76 percent. The sensitivity of recovery efficiency to variations in the rate and duration of injection (0.25, 0.50, 1.0, and 2.0 million gallons per day) and withdrawal cycles (60, 180, and 365 days) was determined. For a given operational scheme, recovery efficiency increased as the injection and withdrawal rate is increased. Model results indicate that recovery efficiencies of between about 23 and 37 percent can be obtained for different subsurface storage and recovery schemes. Five successive injection, storage, and recovery cycles can increase the recovery efficiency to about 46 to 62 percent. There is a larger rate of increase at smaller rates than at larger rates. Over the range of variables studied, recovery efficiency improved with successive cycles, increasing rapidly during initial cycles tyhen more slowly at later cycles. The operation of a single well used for subsurface storage and recovery appears to be technically feasible under moderately favorable conditions; however, the recovery efficiency is higly dependent upon local physical and operational parameters. A combination of hydraulic, chemical, and operational parameters that minimize dispersion and buoyancy flow, maximizes recovery efficiency. Recovery efficiency was optimal where resident formation water density and permeabilities were relatively similar and low.

[Research on the photoelectric conversion efficiency of grating antireflective layer solar cells].

PubMed

Zhong, Hui; Gao, Yong-Yi; Zhou, Ren-Long; Zhou, Bing-ju; Tang, Li-qiang; Wu, Ling-xi; Li, Hong-jian

2011-07-01

A numerical investigation of the effect of grating antireflective layer structure on the photoelectric conversion efficiency of solar cells was carried out by the finite-difference time-domain method. The influence of grating shape, height and the metal film thickness coated on grating surface on energy storage was analyzed in detail. It was found that the comparison between unoptimized and optimized surface grating structure on solar cells shows that the optimization of surface by grating significantly increases the energy storage capability and greatly improves the efficiency, especially of the photoelectric conversion efficiency and energy storage of the triangle grating. As the film thickness increases, energy storage effect increases, while as the film thickness is too thick, energy storage effect becomes lower and lower.

Spectral analysis of GEOS-3 altimeter data and frequency domain collocation. [to estimate gravity anomalies

NASA Technical Reports Server (NTRS)

Eren, K.

1980-01-01

The mathematical background in spectral analysis as applied to geodetic applications is summarized. The resolution (cut-off frequency) of the GEOS 3 altimeter data is examined by determining the shortest wavelength (corresponding to the cut-off frequency) recoverable. The data from some 18 profiles are used. The total power (variance) in the sea surface topography with respect to the reference ellipsoid as well as with respect to the GEM-9 surface is computed. A fast inversion algorithm for matrices of simple and block Toeplitz matrices and its application to least squares collocation is explained. This algorithm yields a considerable gain in computer time and storage in comparison with conventional least squares collocation. Frequency domain least squares collocation techniques are also introduced and applied to estimating gravity anomalies from GEOS 3 altimeter data. These techniques substantially reduce the computer time and requirements in storage associated with the conventional least squares collocation. Numerical examples given demonstrate the efficiency and speed of these techniques.

Preliminary assessment of injection, storage, and recovery of freshwater in the lower Hawthorn aquifer, Cape Coral, Florida

USGS Publications Warehouse

Quinones-Aponte, Vicente; Wexler, Eliezer J.

1995-01-01

A preliminary assessment of subsurface injection, storage and recovery of fresh canal water was made in the naturally brackish lower Hawthorn aquifer in Cape Coral, southwestern Florida. A digital modeling approach was used for this preliminary assessment, incorporating available data on hydrologic conditions, aquifer properties, and water quality to simulate density-dependent ground-water flow and advective-dispersive transport of a conservative ground-water solute (chloride ion). A baseline simulation was used as reference to compare the effects of changing various operational factors on the recovery efficiency. A recovery efficiency of 64 percent was estimated for the baseline simulation. Based on the model, the recovery efficiency increases if the injection rate and recovery rates are increased and if the ratio of recovery rate to injection rate is increased. Recovery efficiency decreases if the amount of water injected is increased; slightly decreases if the storage time is increased; is not changed significantly if the water is injected to a specific flow zone; increases with successive cycles of injection, storage, and recovery; and decreases if the chloride concentrations in either the injection water or native aquifer water are increased. In everal hypothetical tests, the recovery efficiency fluctuated between 22 and about 100 percent. Two successive cycles could bring the recovery efficiency from 60 to about 80 percent. Interlayer solute mass movement across the upper and lower boundaries seems to be the most important factor affecting the recovery efficiency. A sensitivity analysis was performed applying a technique in which the change in the various factors and the corresponding model responses are normalized so that meaningful comparisons among the responses could be made. The general results from the sensitivity analysis indicated that the permeabilities of the upper and lower flow zones were the most important factors that produced the greatest changes in the relative sensitivity of the recovery efficiency. Almost equally significant changes occurred in the relative sensitivity of the recovery efficiency when all porosity values of the upper and lower flow zones and the leaky confining units and the vertical anisotropy ratio were changed. The advective factors are the most important in the Cape Coral area according to the sensitivity analysis. However, the dispersivity values used in the model were extrapolated from studies conducted at the nearby Lee County Water Treatment Plant, and these values might not be representative of the actual dispersive characteristics of the lower Hawthorn aquifer in the Cape Coral area.

CO2 storage capacity estimation: Issues and development of standards

USGS Publications Warehouse

Bradshaw, J.; Bachu, S.; Bonijoly, D.; Burruss, R.; Holloway, S.; Christensen, N.P.; Mathiassen, O.M.

2007-01-01

Associated with the endeavours of geoscientists to pursue the promise that geological storage of CO2 has of potentially making deep cuts into greenhouse gas emissions, Governments around the world are dependent on reliable estimates of CO2 storage capacity and insightful indications of the viability of geological storage in their respective jurisdictions. Similarly, industry needs reliable estimates for business decisions regarding site selection and development. If such estimates are unreliable, and decisions are made based on poor advice, then valuable resources and time could be wasted. Policies that have been put in place to address CO2 emissions could be jeopardised. Estimates need to clearly state the limitations that existed (data, time, knowledge) at the time of making the assessment and indicate the purpose and future use to which the estimates should be applied. A set of guidelines for estimation of storage capacity will greatly assist future deliberations by government and industry on the appropriateness of geological storage of CO2 in different geological settings and political jurisdictions. This work has been initiated under the auspices of the Carbon Sequestration Leadership Forum (www.cslforum.org), and it is intended that it will be an ongoing taskforce to further examine issues associated with storage capacity estimation. Crown Copyright ?? 2007.

Using Firn Air for Facility Cooling at the WAIS Divide Site

DTIC Science & Technology

2014-09-17

reduce logistics costs at remote field camps where it is critical to maintain proper temperatures to preserve sensitive deep ice cores. We assessed the...feasibility of using firn air for cooling at the West Antarc- tic Ice Sheet (WAIS) Divide ice core drilling site as a means to adequately and...efficiently refrigerate ice cores during storage and processing. We used estimates of mean annual temperature, temperature variations, and firn

Methods to assess geological CO2 storage capacity: Status and best practice

USGS Publications Warehouse

Heidug, Wolf; Brennan, Sean T.; Holloway, Sam; Warwick, Peter D.; McCoy, Sean; Yoshimura, Tsukasa

2013-01-01

To understand the emission reduction potential of carbon capture and storage (CCS), decision makers need to understand the amount of CO2 that can be safely stored in the subsurface and the geographical distribution of storage resources. Estimates of storage resources need to be made using reliable and consistent methods. Previous estimates of CO2 storage potential for a range of countries and regions have been based on a variety of methodologies resulting in a correspondingly wide range of estimates. Consequently, there has been uncertainty about which of the methodologies were most appropriate in given settings, and whether the estimates produced by these methods were useful to policy makers trying to determine the appropriate role of CCS. In 2011, the IEA convened two workshops which brought together experts for six national surveys organisations to review CO2 storage assessment methodologies and make recommendations on how to harmonise CO2 storage estimates worldwide. This report presents the findings of these workshops and an internationally shared guideline for quantifying CO2 storage resources.

Probabilistic Assessment of Above Zone Pressure Predictions at a Geologic Carbon Storage Site

PubMed Central

Namhata, Argha; Oladyshkin, Sergey; Dilmore, Robert M.; Zhang, Liwei; Nakles, David V.

2016-01-01

Carbon dioxide (CO2) storage into geological formations is regarded as an important mitigation strategy for anthropogenic CO2 emissions to the atmosphere. This study first simulates the leakage of CO2 and brine from a storage reservoir through the caprock. Then, we estimate the resulting pressure changes at the zone overlying the caprock also known as Above Zone Monitoring Interval (AZMI). A data-driven approach of arbitrary Polynomial Chaos (aPC) Expansion is then used to quantify the uncertainty in the above zone pressure prediction based on the uncertainties in different geologic parameters. Finally, a global sensitivity analysis is performed with Sobol indices based on the aPC technique to determine the relative importance of different parameters on pressure prediction. The results indicate that there can be uncertainty in pressure prediction locally around the leakage zones. The degree of such uncertainty in prediction depends on the quality of site specific information available for analysis. The scientific results from this study provide substantial insight that there is a need for site-specific data for efficient predictions of risks associated with storage activities. The presented approach can provide a basis of optimized pressure based monitoring network design at carbon storage sites. PMID:27996043

Probabilistic Assessment of Above Zone Pressure Predictions at a Geologic Carbon Storage Site

NASA Astrophysics Data System (ADS)

Namhata, Argha; Oladyshkin, Sergey; Dilmore, Robert M.; Zhang, Liwei; Nakles, David V.

2016-12-01

Carbon dioxide (CO2) storage into geological formations is regarded as an important mitigation strategy for anthropogenic CO2 emissions to the atmosphere. This study first simulates the leakage of CO2 and brine from a storage reservoir through the caprock. Then, we estimate the resulting pressure changes at the zone overlying the caprock also known as Above Zone Monitoring Interval (AZMI). A data-driven approach of arbitrary Polynomial Chaos (aPC) Expansion is then used to quantify the uncertainty in the above zone pressure prediction based on the uncertainties in different geologic parameters. Finally, a global sensitivity analysis is performed with Sobol indices based on the aPC technique to determine the relative importance of different parameters on pressure prediction. The results indicate that there can be uncertainty in pressure prediction locally around the leakage zones. The degree of such uncertainty in prediction depends on the quality of site specific information available for analysis. The scientific results from this study provide substantial insight that there is a need for site-specific data for efficient predictions of risks associated with storage activities. The presented approach can provide a basis of optimized pressure based monitoring network design at carbon storage sites.

Development and Experimental Benchmark of Simulations to Predict Used Nuclear Fuel Cladding Temperatures during Drying and Transfer Operations

DOE Office of Scientific and Technical Information (OSTI.GOV)

Greiner, Miles

Radial hydride formation in high-burnup used fuel cladding has the potential to radically reduce its ductility and suitability for long-term storage and eventual transport. To avoid this formation, the maximum post-reactor temperature must remain sufficiently low to limit the cladding hoop stress, and so that hydrogen from the existing circumferential hydrides will not dissolve and become available to re-precipitate into radial hydrides under the slow cooling conditions during drying, transfer and early dry-cask storage. The objective of this research is to develop and experimentallybenchmark computational fluid dynamics simulations of heat transfer in post-pool-storage drying operations, when high-burnup fuel cladding ismore » likely to experience its highest temperature. These benchmarked tools can play a key role in evaluating dry cask storage systems for extended storage of high-burnup fuels and post-storage transportation, including fuel retrievability. The benchmarked tools will be used to aid the design of efficient drying processes, as well as estimate variations of surface temperatures as a means of inferring helium integrity inside the canister or cask. This work will be conducted effectively because the principal investigator has experience developing these types of simulations, and has constructed a test facility that can be used to benchmark them.« less

Enhancement of diffraction efficiency and storage life of poly(vinyl chloride)-based optical recording medium with incorporation of an electron donor

NASA Astrophysics Data System (ADS)

John, Beena Mary; Ushamani, M.; Sreekumar, K.; Joseph, Rani; Sudha Kartha, C.

2007-01-01

The diffraction efficiency, sensitivity, and storage life of methylene blue-sensitized poly(vinyl chloride) film was improved by the addition of an electron donor in the matrix. The addition of pyridine enhanced the diffraction efficiency by two times, and storage life of the gratings was increased to 2-3 days.

Towards Regional, Error-Bounded Landscape Carbon Storage Estimates for Data-Deficient Areas of the World

PubMed Central

Willcock, Simon; Phillips, Oliver L.; Platts, Philip J.; Balmford, Andrew; Burgess, Neil D.; Lovett, Jon C.; Ahrends, Antje; Bayliss, Julian; Doggart, Nike; Doody, Kathryn; Fanning, Eibleis; Green, Jonathan; Hall, Jaclyn; Howell, Kim L.; Marchant, Rob; Marshall, Andrew R.; Mbilinyi, Boniface; Munishi, Pantaleon K. T.; Owen, Nisha; Swetnam, Ruth D.; Topp-Jorgensen, Elmer J.; Lewis, Simon L.

2012-01-01

Monitoring landscape carbon storage is critical for supporting and validating climate change mitigation policies. These may be aimed at reducing deforestation and degradation, or increasing terrestrial carbon storage at local, regional and global levels. However, due to data-deficiencies, default global carbon storage values for given land cover types such as ‘lowland tropical forest’ are often used, termed ‘Tier 1 type’ analyses by the Intergovernmental Panel on Climate Change (IPCC). Such estimates may be erroneous when used at regional scales. Furthermore uncertainty assessments are rarely provided leading to estimates of land cover change carbon fluxes of unknown precision which may undermine efforts to properly evaluate land cover policies aimed at altering land cover dynamics. Here, we present a repeatable method to estimate carbon storage values and associated 95% confidence intervals (CI) for all five IPCC carbon pools (aboveground live carbon, litter, coarse woody debris, belowground live carbon and soil carbon) for data-deficient regions, using a combination of existing inventory data and systematic literature searches, weighted to ensure the final values are regionally specific. The method meets the IPCC ‘Tier 2’ reporting standard. We use this method to estimate carbon storage over an area of33.9 million hectares of eastern Tanzania, reporting values for 30 land cover types. We estimate that this area stored 6.33 (5.92–6.74) Pg C in the year 2000. Carbon storage estimates for the same study area extracted from five published Africa-wide or global studies show a mean carbon storage value of ∼50% of that reported using our regional values, with four of the five studies reporting lower carbon storage values. This suggests that carbon storage may have been underestimated for this region of Africa. Our study demonstrates the importance of obtaining regionally appropriate carbon storage estimates, and shows how such values can be produced for a relatively low investment. PMID:23024764

Towards regional, error-bounded landscape carbon storage estimates for data-deficient areas of the world.

PubMed

Willcock, Simon; Phillips, Oliver L; Platts, Philip J; Balmford, Andrew; Burgess, Neil D; Lovett, Jon C; Ahrends, Antje; Bayliss, Julian; Doggart, Nike; Doody, Kathryn; Fanning, Eibleis; Green, Jonathan; Hall, Jaclyn; Howell, Kim L; Marchant, Rob; Marshall, Andrew R; Mbilinyi, Boniface; Munishi, Pantaleon K T; Owen, Nisha; Swetnam, Ruth D; Topp-Jorgensen, Elmer J; Lewis, Simon L

2012-01-01

Monitoring landscape carbon storage is critical for supporting and validating climate change mitigation policies. These may be aimed at reducing deforestation and degradation, or increasing terrestrial carbon storage at local, regional and global levels. However, due to data-deficiencies, default global carbon storage values for given land cover types such as 'lowland tropical forest' are often used, termed 'Tier 1 type' analyses by the Intergovernmental Panel on Climate Change (IPCC). Such estimates may be erroneous when used at regional scales. Furthermore uncertainty assessments are rarely provided leading to estimates of land cover change carbon fluxes of unknown precision which may undermine efforts to properly evaluate land cover policies aimed at altering land cover dynamics. Here, we present a repeatable method to estimate carbon storage values and associated 95% confidence intervals (CI) for all five IPCC carbon pools (aboveground live carbon, litter, coarse woody debris, belowground live carbon and soil carbon) for data-deficient regions, using a combination of existing inventory data and systematic literature searches, weighted to ensure the final values are regionally specific. The method meets the IPCC 'Tier 2' reporting standard. We use this method to estimate carbon storage over an area of33.9 million hectares of eastern Tanzania, reporting values for 30 land cover types. We estimate that this area stored 6.33 (5.92-6.74) Pg C in the year 2000. Carbon storage estimates for the same study area extracted from five published Africa-wide or global studies show a mean carbon storage value of ∼50% of that reported using our regional values, with four of the five studies reporting lower carbon storage values. This suggests that carbon storage may have been underestimated for this region of Africa. Our study demonstrates the importance of obtaining regionally appropriate carbon storage estimates, and shows how such values can be produced for a relatively low investment.

Phase change energy storage for solar dynamic power systems

NASA Technical Reports Server (NTRS)

Chiaramonte, F. P.; Taylor, J. D.

1992-01-01

This paper presents the results of a transient computer simulation that was developed to study phase change energy storage techniques for Space Station Freedom (SSF) solar dynamic (SD) power systems. Such SD systems may be used in future growth SSF configurations. Two solar dynamic options are considered in this paper: Brayton and Rankine. Model elements consist of a single node receiver and concentrator, and takes into account overall heat engine efficiency and power distribution characteristics. The simulation not only computes the energy stored in the receiver phase change material (PCM), but also the amount of the PCM required for various combinations of load demands and power system mission constraints. For a solar dynamic power system in low earth orbit, the amount of stored PCM energy is calculated by balancing the solar energy input and the energy consumed by the loads corrected by an overall system efficiency. The model assumes an average 75 kW SD power system load profile which is connected to user loads via dedicated power distribution channels. The model then calculates the stored energy in the receiver and subsequently estimates the quantity of PCM necessary to meet peaking and contingency requirements. The model can also be used to conduct trade studies on the performance of SD power systems using different storage materials.

Phase change energy storage for solar dynamic power systems

NASA Astrophysics Data System (ADS)

Chiaramonte, F. P.; Taylor, J. D.

This paper presents the results of a transient computer simulation that was developed to study phase change energy storage techniques for Space Station Freedom (SSF) solar dynamic (SD) power systems. Such SD systems may be used in future growth SSF configurations. Two solar dynamic options are considered in this paper: Brayton and Rankine. Model elements consist of a single node receiver and concentrator, and takes into account overall heat engine efficiency and power distribution characteristics. The simulation not only computes the energy stored in the receiver phase change material (PCM), but also the amount of the PCM required for various combinations of load demands and power system mission constraints. For a solar dynamic power system in low earth orbit, the amount of stored PCM energy is calculated by balancing the solar energy input and the energy consumed by the loads corrected by an overall system efficiency. The model assumes an average 75 kW SD power system load profile which is connected to user loads via dedicated power distribution channels. The model then calculates the stored energy in the receiver and subsequently estimates the quantity of PCM necessary to meet peaking and contingency requirements. The model can also be used to conduct trade studies on the performance of SD power systems using different storage materials.

GTZ: a fast compression and cloud transmission tool optimized for FASTQ files.

PubMed

Xing, Yuting; Li, Gen; Wang, Zhenguo; Feng, Bolun; Song, Zhuo; Wu, Chengkun

2017-12-28

The dramatic development of DNA sequencing technology is generating real big data, craving for more storage and bandwidth. To speed up data sharing and bring data to computing resource faster and cheaper, it is necessary to develop a compression tool than can support efficient compression and transmission of sequencing data onto the cloud storage. This paper presents GTZ, a compression and transmission tool, optimized for FASTQ files. As a reference-free lossless FASTQ compressor, GTZ treats different lines of FASTQ separately, utilizes adaptive context modelling to estimate their characteristic probabilities, and compresses data blocks with arithmetic coding. GTZ can also be used to compress multiple files or directories at once. Furthermore, as a tool to be used in the cloud computing era, it is capable of saving compressed data locally or transmitting data directly into cloud by choice. We evaluated the performance of GTZ on some diverse FASTQ benchmarks. Results show that in most cases, it outperforms many other tools in terms of the compression ratio, speed and stability. GTZ is a tool that enables efficient lossless FASTQ data compression and simultaneous data transmission onto to cloud. It emerges as a useful tool for NGS data storage and transmission in the cloud environment. GTZ is freely available online at: https://github.com/Genetalks/gtz .

Acceleration and Storage of Energetic Electrons in Magnetic Loops in the Course of Electric Current Oscillations

NASA Astrophysics Data System (ADS)

Zaitsev, V. V.; Stepanov, A. V.

2017-10-01

A mechanism of electron acceleration and storage of energetic particles in solar and stellar coronal magnetic loops, based on oscillations of the electric current, is considered. The magnetic loop is presented as an electric circuit with the electric current generated by convective motions in the photosphere. Eigenoscillations of the electric current in a loop induce an electric field directed along the loop axis. It is shown that the sudden reductions that occur in the course of type IV continuum and pulsating type III observed in various frequency bands (25 - 180 MHz, 110 - 600 MHz, 0.7 - 3.0 GHz) in solar flares provide evidence for acceleration and storage of the energetic electrons in coronal magnetic loops. We estimate the energization rate and the energy of accelerated electrons and present examples of the storage of energetic electrons in loops in the course of flares on the Sun or on ultracool stars. We also discuss the efficiency of the suggested mechanism as compared with the electron acceleration during the five-minute photospheric oscillations and with the acceleration driven by the magnetic Rayleigh-Taylor instability.

Fuel economy of hybrid fuel-cell vehicles

NASA Astrophysics Data System (ADS)

Ahluwalia, Rajesh K.; Wang, X.; Rousseau, A.

The potential improvement in fuel economy of a mid-size fuel-cell vehicle by combining it with an energy storage system has been assessed. An energy management strategy is developed and used to operate the direct hydrogen, pressurized fuel-cell system in a load-following mode and the energy storage system in a charge-sustaining mode. The strategy places highest priority on maintaining the energy storage system in a state where it can supply unanticipated boost power when the fuel-cell system alone cannot meet the power demand. It is found that downsizing a fuel-cell system decreases its efficiency on a drive cycle which is compensated by partial regenerative capture of braking energy. On a highway cycle with limited braking energy the increase in fuel economy with hybridization is small but on the stop-and-go urban cycle the fuel economy can improve by 27%. On the combined highway and urban drive cycles the fuel economy of the fuel-cell vehicle is estimated to increase by up to 15% by hybridizing it with an energy storage system.

Using Pressure and Volumetric Approaches to Estimate CO2 Storage Capacity in Deep Saline Aquifers

DOE PAGES

Thibeau, Sylvain; Bachu, Stefan; Birkholzer, Jens; ...

2014-12-31

Various approaches are used to evaluate the capacity of saline aquifers to store CO 2, resulting in a wide range of capacity estimates for a given aquifer. The two approaches most used are the volumetric “open aquifer” and “closed aquifer” approaches. We present four full-scale aquifer cases, where CO 2 storage capacity is evaluated both volumetrically (with “open” and/or “closed” approaches) and through flow modeling. These examples show that the “open aquifer” CO 2 storage capacity estimation can strongly exceed the cumulative CO 2 injection from the flow model, whereas the “closed aquifer” estimates are a closer approximation to themore » flow-model derived capacity. An analogy to oil recovery mechanisms is presented, where the primary oil recovery mechanism is compared to CO 2 aquifer storage without producing formation water; and the secondary oil recovery mechanism (water flooding) is compared to CO 2 aquifer storage performed simultaneously with extraction of water for pressure maintenance. This analogy supports the finding that the “closed aquifer” approach produces a better estimate of CO 2 storage without water extraction, and highlights the need for any CO 2 storage estimate to specify whether it is intended to represent CO 2 storage capacity with or without water extraction.« less

Quantifying watershed surface depression storage: determination and application in a hydrologic model

Treesearch

Joseph K. O. Amoah; Devendra M. Amatya; Soronnadi Nnaji

2012-01-01

Hydrologic models often require correct estimates of surface macro-depressional storage to accurately simulate rainfall–runoff processes. Traditionally, depression storage is determined through model calibration or lumped with soil storage components or on an ad hoc basis. This paper investigates a holistic approach for estimating surface depressional storage capacity...

Classification of CO2 Geologic Storage: Resource and Capacity

USGS Publications Warehouse

Frailey, S.M.; Finley, R.J.

2009-01-01

The use of the term capacity to describe possible geologic storage implies a realistic or likely volume of CO2 to be sequestered. Poor data quantity and quality may lead to very high uncertainty in the storage estimate. Use of the term "storage resource" alleviates the implied certainty of the term "storage capacity". This is especially important to non- scientists (e.g. policy makers) because "capacity" is commonly used to describe the very specific and more certain quantities such as volume of a gas tank or a hotel's overnight guest limit. Resource is a term used in the classification of oil and gas accumulations to infer lesser certainty in the commercial production of oil and gas. Likewise for CO2 sequestration, a suspected porous and permeable zone can be classified as a resource, but capacity can only be estimated after a well is drilled into the formation and a relatively higher degree of economic and regulatory certainty is established. Storage capacity estimates are lower risk or higher certainty compared to storage resource estimates. In the oil and gas industry, prospective resource and contingent resource are used for estimates with less data and certainty. Oil and gas reserves are classified as Proved and Unproved, and by analogy, capacity can be classified similarly. The highest degree of certainty for an oil or gas accumulation is Proved, Developed Producing (PDP) Reserves. For CO2 sequestration this could be Proved Developed Injecting (PDI) Capacity. A geologic sequestration storage classification system is developed by analogy to that used by the oil and gas industry. When a CO2 sequestration industry emerges, storage resource and capacity estimates will be considered a company asset and consequently regulated by the Securities and Exchange Commission. Additionally, storage accounting and auditing protocols will be required to confirm projected storage estimates and assignment of credits from actual injection. An example illustrates the use of these terms and how storage classification changes as new data become available. ?? 2009 Elsevier Ltd. All rights reserved.

Hybrid Hydro Renewable Energy Storage Model

NASA Astrophysics Data System (ADS)

Dey, Asit Kr

2018-01-01

This paper aims at presenting wind & tidal turbine pumped-storage solutions for improving the energy efficiency and economic sustainability of renewable energy systems. Indicated a viable option to solve problems of energy production, as well as in the integration of intermittent renewable energies, providing system flexibility due to energy load’s fluctuation, as long as the storage of energy from intermittent sources. Sea water storage energy is one of the best and most efficient options in terms of renewable resources as an integrated solution allowing the improvement of the energy system elasticity and the global system efficiency.

Estimates of Storage Capacity of Multilayer Perceptron with Threshold Logic Hidden Units.

PubMed

Kowalczyk, Adam

1997-11-01

We estimate the storage capacity of multilayer perceptron with n inputs, h(1) threshold logic units in the first hidden layer and 1 output. We show that if the network can memorize 50% of all dichotomies of a randomly selected N-tuple of points of R(n) with probability 1, then N

Combined statistical analyses for long-term stability data with multiple storage conditions: a simulation study.

PubMed

Almalik, Osama; Nijhuis, Michiel B; van den Heuvel, Edwin R

2014-01-01

Shelf-life estimation usually requires that at least three registration batches are tested for stability at multiple storage conditions. The shelf-life estimates are often obtained by linear regression analysis per storage condition, an approach implicitly suggested by ICH guideline Q1E. A linear regression analysis combining all data from multiple storage conditions was recently proposed in the literature when variances are homogeneous across storage conditions. The combined analysis is expected to perform better than the separate analysis per storage condition, since pooling data would lead to an improved estimate of the variation and higher numbers of degrees of freedom, but this is not evident for shelf-life estimation. Indeed, the two approaches treat the observed initial batch results, the intercepts in the model, and poolability of batches differently, which may eliminate or reduce the expected advantage of the combined approach with respect to the separate approach. Therefore, a simulation study was performed to compare the distribution of simulated shelf-life estimates on several characteristics between the two approaches and to quantify the difference in shelf-life estimates. In general, the combined statistical analysis does estimate the true shelf life more consistently and precisely than the analysis per storage condition, but it did not outperform the separate analysis in all circumstances.

Estimating hydraulic properties of the Floridan Aquifer System by analysis of earth-tide, ocean-tide, and barometric effects, Collier and Hendry Counties, Florida

USGS Publications Warehouse

Merritt, Michael L.

2004-01-01

Aquifers are subjected to mechanical stresses from natural, non-anthropogenic, processes such as pressure loading or mechanical forcing of the aquifer by ocean tides, earth tides, and pressure fluctuations in the atmosphere. The resulting head fluctuations are evident even in deep confined aquifers. The present study was conducted for the purpose of reviewing the research that has been done on the use of these phenomena for estimating the values of aquifer properties, and determining which of the analytical techniques might be useful for estimating hydraulic properties in the dissolved-carbonate hydrologic environment of southern Florida. Fifteen techniques are discussed in this report, of which four were applied.An analytical solution for head oscillations in a well near enough to the ocean to be influenced by ocean tides was applied to data from monitor zones in a well near Naples, Florida. The solution assumes a completely non-leaky confining unit of infinite extent. Resulting values of transmissivity are in general agreement with the results of aquifer performance tests performed by the South Florida Water Management District. There seems to be an inconsistency between results of the amplitude ratio analysis and independent estimates of loading efficiency. A more general analytical solution that takes leakage through the confining layer into account yielded estimates that were lower than those obtained using the non-leaky method, and closer to the South Florida Water Management District estimates. A numerical model with a cross-sectional grid design was applied to explore additional aspects of the problem.A relation between specific storage and the head oscillation observed in a well provided estimates of specific storage that were considered reasonable. Porosity estimates based on the specific storage estimates were consistent with values obtained from measurements on core samples. Methods are described for determining aquifer diffusivity by comparing the time-varying drawdown in an open well with periodic pressure-head oscillations in the aquifer, but the applicability of such methods might be limited in studies of the Floridan aquifer system.

Carbon storage in China's forest ecosystems: estimation by different integrative methods.

PubMed

Peng, Shunlei; Wen, Ding; He, Nianpeng; Yu, Guirui; Ma, Anna; Wang, Qiufeng

2016-05-01

Carbon (C) storage for all the components, especially dead mass and soil organic carbon, was rarely reported and remained uncertainty in China's forest ecosystems. This study used field-measured data published between 2004 and 2014 to estimate C storage by three forest type classifications and three spatial interpolations and assessed the uncertainty in C storage resulting from different integrative methods in China's forest ecosystems. The results showed that C storage in China's forest ecosystems ranged from 30.99 to 34.96 Pg C by the six integrative methods. We detected 5.0% variation (coefficient of variation, CV, %) among the six methods, which was influenced mainly by soil C estimates. Soil C density and storage in the 0-100 cm soil layer were estimated to be 136.11-153.16 Mg C·ha(-1) and 20.63-23.21 Pg C, respectively. Dead mass C density and storage were estimated to be 3.66-5.41 Mg C·ha(-1) and 0.68-0.82 Pg C, respectively. Mean C storage in China's forest ecosystems estimated by the six integrative methods was 8.557 Pg C (25.8%) for aboveground biomass, 1.950 Pg C (5.9%) for belowground biomass, 0.697 Pg C (2.1%) for dead mass, and 21.958 Pg C (66.2%) for soil organic C in the 0-100 cm soil layer. The R:S ratio was 0.23, and C storage in the soil was 2.1 times greater than in the vegetation. Carbon storage estimates with respect to forest type classification (38 forest subtypes) were closer to the average value than those calculated using the spatial interpolation methods. Variance among different methods and data sources may partially explain the high uncertainty of C storage detected by different studies. This study demonstrates the importance of using multimethodological approaches to estimate C storage accurately in the large-scale forest ecosystems.

GLIDES – Efficient Energy Storage from ORNL

ScienceCinema

Momen, Ayyoub M.; Abu-Heiba, Ahmad; Odukomaiya, Wale; Akinina, Alla

2018-06-25

The research shown in this video features the GLIDES (Ground-Level Integrated Diverse Energy Storage) project, which has been under development at Oak Ridge National Laboratory (ORNL) since 2013. GLIDES can store energy via combined inputs of electricity and heat, and deliver dispatchable electricity. Supported by ORNL’s Laboratory Director’s Research and Development (LDRD) fund, this energy storage system is low-cost, and hybridizes compressed air and pumped-hydro approaches to allow for storage of intermittent renewable energy at high efficiency. A U.S. patent application for this novel energy storage concept has been submitted, and research findings suggest it has the potential to be a flexible, low-cost, scalable, high-efficiency option for energy storage, especially useful in residential and commercial buildings.

GLIDES – Efficient Energy Storage from ORNL

DOE Office of Scientific and Technical Information (OSTI.GOV)

Momen, Ayyoub M.; Abu-Heiba, Ahmad; Odukomaiya, Wale

2016-03-01

The research shown in this video features the GLIDES (Ground-Level Integrated Diverse Energy Storage) project, which has been under development at Oak Ridge National Laboratory (ORNL) since 2013. GLIDES can store energy via combined inputs of electricity and heat, and deliver dispatchable electricity. Supported by ORNL’s Laboratory Director’s Research and Development (LDRD) fund, this energy storage system is low-cost, and hybridizes compressed air and pumped-hydro approaches to allow for storage of intermittent renewable energy at high efficiency. A U.S. patent application for this novel energy storage concept has been submitted, and research findings suggest it has the potential to bemore » a flexible, low-cost, scalable, high-efficiency option for energy storage, especially useful in residential and commercial buildings.« less

Air Brayton Solar Receiver, phase 1

NASA Technical Reports Server (NTRS)

Zimmerman, D. K.

1979-01-01

A six month analysis and conceptual design study of an open cycle Air Brayton Solar Receiver (ABSR) for use on a tracking, parabolic solar concentrator are discussed. The ABSR, which includes a buffer storage system, is designed to provide inlet air to a power conversion unit. Parametric analyses, conceptual design, interface requirements, and production cost estimates are described. The design features were optimized to yield a zero maintenance, low cost, high efficiency concept that will provide a 30 year operational life.

Statistical processing of large image sequences.

PubMed

Khellah, F; Fieguth, P; Murray, M J; Allen, M

2005-01-01

The dynamic estimation of large-scale stochastic image sequences, as frequently encountered in remote sensing, is important in a variety of scientific applications. However, the size of such images makes conventional dynamic estimation methods, for example, the Kalman and related filters, impractical. In this paper, we present an approach that emulates the Kalman filter, but with considerably reduced computational and storage requirements. Our approach is illustrated in the context of a 512 x 512 image sequence of ocean surface temperature. The static estimation step, the primary contribution here, uses a mixture of stationary models to accurately mimic the effect of a nonstationary prior, simplifying both computational complexity and modeling. Our approach provides an efficient, stable, positive-definite model which is consistent with the given correlation structure. Thus, the methods of this paper may find application in modeling and single-frame estimation.

Efficient Algorithms for Estimating the Absorption Spectrum within Linear Response TDDFT

DOE Office of Scientific and Technical Information (OSTI.GOV)

Brabec, Jiri; Lin, Lin; Shao, Meiyue

We present two iterative algorithms for approximating the absorption spectrum of molecules within linear response of time-dependent density functional theory (TDDFT) framework. These methods do not attempt to compute eigenvalues or eigenvectors of the linear response matrix. They are designed to approximate the absorption spectrum as a function directly. They take advantage of the special structure of the linear response matrix. Neither method requires the linear response matrix to be constructed explicitly. They only require a procedure that performs the multiplication of the linear response matrix with a vector. These methods can also be easily modified to efficiently estimate themore » density of states (DOS) of the linear response matrix without computing the eigenvalues of this matrix. We show by computational experiments that the methods proposed in this paper can be much more efficient than methods that are based on the exact diagonalization of the linear response matrix. We show that they can also be more efficient than real-time TDDFT simulations. We compare the pros and cons of these methods in terms of their accuracy as well as their computational and storage cost.« less

Assessment of the Potential for Flux Estimation Using Concentration Data from Mobile Surveys

NASA Astrophysics Data System (ADS)

Gyenis, A.; Zahasky, C.; Moriarty, D. M.; Benson, S. M.

2014-12-01

Carbon capture and storage is a climate change mitigation technology with the potential to serve as a bridge technology as society transitions from a fossil fuel dependent energy system to a renewable energy dominated system. One of the greatest concerns associated with wide-scale adoption of carbon capture and storage technology is the risk of carbon dioxide leakage from sequestration reservoirs. Thus there is a need to develop efficient and effective strategies for monitoring and verification of geologically stored carbon dioxide. To evaluate the potential for estimating leakage fluxes based on mobile surveys, we establish correlations between concentration data and flux measurements made with a flux chamber. These correlations are then used to estimate leakage fluxes over a 70-meter long horizontal well buried approximately 1.8 meters below the surface at the Zero Emissions Research and Technology (ZERT) facility operated by Montana State University. The CO2 had a leakage rate of 0.15 t/d, which is comparable to a small leak in an industrial scale project (0.005% of a 1 Mt/yr storage project). A Picarro gas analyzer was used to measure 12CO2 and 13CO2 at heights of 3 cm above the ground surface. Previous studies (Moriarty, 2014) show that concentration data at this height provides a very high likelihood (>95%) of detecting leaks within a distance of 2.5 m of the leak. Measured concentration data show a noisy but significant correlation with flux measurements, thus providing the possibility to obtain rough estimates of leakage fluxes from mobile measurements. Moriarty, Dylan, 2014. Rapid Surface Detection of CO2 Leaks from Geologic Sequestration Sites. MS Thesis, Stanford University.

Storage requirements for Georgia streams

USGS Publications Warehouse

Carter, Robert F.

1983-01-01

The suitability of a stream as a source of water supply or for waste disposal may be severely limited by low flow during certain periods. A water user may be forced to provide storage facilities to supplement the natural flow if the low flow is insufficient for his needs. This report provides data for evaluating the feasibility of augmenting low streamflow by means of storage facilities. It contains tabular data on storage requirements for draft rates that are as much as 60 percent of the mean annual flow at 99 continuous-record gaging stations, and draft-storage diagrams for estimating storage requirements at many additional sites. Through analyses of streamflow data, the State was divided into four regions. Draft-storage diagrams for each region provide a means of estimating storage requirements for sites on streams where data are scant, provided the drainage area, mean annual flow, and the 7-day, 10-year low flow are known or can be estimated. These data are tabulated for the 99 gaging stations used in the analyses and for 102 partial-record sites where only base-flow measurements have been made. The draft-storage diagrams are useful not only for estimating in-channel storage required for low-flow augmentation, but also can be used for estimating the volume of off-channel storage required to retain wastewater during low-flow periods for later release. In addition, these relationships can be helpful in estimating the volume of wastewater to be disposed of by spraying on land, provided that the water disposed of in this manner is only that for which streamflow dilution water is not currently available. Mean annual flow can be determined for any stream within the State by using the runoff map in this report. Low-flow indices can be estimated by several methods, including correlation of base-flow measurements with concurrent flow at nearby continuous-record gaging stations where low-flow indices have been determined.

Highly-efficient quantum memory for polarization qubits in a spatially-multiplexed cold atomic ensemble.

PubMed

Vernaz-Gris, Pierre; Huang, Kun; Cao, Mingtao; Sheremet, Alexandra S; Laurat, Julien

2018-01-25

Quantum memory for flying optical qubits is a key enabler for a wide range of applications in quantum information. A critical figure of merit is the overall storage and retrieval efficiency. So far, despite the recent achievements of efficient memories for light pulses, the storage of qubits has suffered from limited efficiency. Here we report on a quantum memory for polarization qubits that combines an average conditional fidelity above 99% and efficiency around 68%, thereby demonstrating a reversible qubit mapping where more information is retrieved than lost. The qubits are encoded with weak coherent states at the single-photon level and the memory is based on electromagnetically-induced transparency in an elongated laser-cooled ensemble of cesium atoms, spatially multiplexed for dual-rail storage. This implementation preserves high optical depth on both rails, without compromise between multiplexing and storage efficiency. Our work provides an efficient node for future tests of quantum network functionalities and advanced photonic circuits.

Coherent Optical Memory with High Storage Efficiency and Large Fractional Delay

NASA Astrophysics Data System (ADS)

Chen, Yi-Hsin; Lee, Meng-Jung; Wang, I.-Chung; Du, Shengwang; Chen, Yong-Fan; Chen, Ying-Cheng; Yu, Ite A.

2013-02-01

A high-storage efficiency and long-lived quantum memory for photons is an essential component in long-distance quantum communication and optical quantum computation. Here, we report a 78% storage efficiency of light pulses in a cold atomic medium based on the effect of electromagnetically induced transparency. At 50% storage efficiency, we obtain a fractional delay of 74, which is the best up-to-date record. The classical fidelity of the recalled pulse is better than 90% and nearly independent of the storage time, as confirmed by the direct measurement of phase evolution of the output light pulse with a beat-note interferometer. Such excellent phase coherence between the stored and recalled light pulses suggests that the current result may be readily applied to single photon wave packets. Our work significantly advances the technology of electromagnetically induced transparency-based optical memory and may find practical applications in long-distance quantum communication and optical quantum computation.

Coherent optical memory with high storage efficiency and large fractional delay.

PubMed

Chen, Yi-Hsin; Lee, Meng-Jung; Wang, I-Chung; Du, Shengwang; Chen, Yong-Fan; Chen, Ying-Cheng; Yu, Ite A

2013-02-22

A high-storage efficiency and long-lived quantum memory for photons is an essential component in long-distance quantum communication and optical quantum computation. Here, we report a 78% storage efficiency of light pulses in a cold atomic medium based on the effect of electromagnetically induced transparency. At 50% storage efficiency, we obtain a fractional delay of 74, which is the best up-to-date record. The classical fidelity of the recalled pulse is better than 90% and nearly independent of the storage time, as confirmed by the direct measurement of phase evolution of the output light pulse with a beat-note interferometer. Such excellent phase coherence between the stored and recalled light pulses suggests that the current result may be readily applied to single photon wave packets. Our work significantly advances the technology of electromagnetically induced transparency-based optical memory and may find practical applications in long-distance quantum communication and optical quantum computation.

Design tool for estimating chemical hydrogen storage system characteristics for light-duty fuel cell vehicles

DOE Office of Scientific and Technical Information (OSTI.GOV)

Brooks, Kriston P.; Sprik, Samuel J.; Tamburello, David A.

The U.S. Department of Energy (DOE) has developed a vehicle framework model to simulate fuel cell-based light-duty vehicle operation for various hydrogen storage systems. This transient model simulates the performance of the storage system, fuel cell, and vehicle for comparison to DOE’s Technical Targets using four drive cycles/profiles. Chemical hydrogen storage models have been developed for the Framework model for both exothermic and endothermic materials. Despite the utility of such models, they require that material researchers input system design specifications that cannot be easily estimated. To address this challenge, a design tool has been developed that allows researchers to directlymore » enter kinetic and thermodynamic chemical hydrogen storage material properties into a simple sizing module that then estimates the systems parameters required to run the storage system model. Additionally, this design tool can be used as a standalone executable file to estimate the storage system mass and volume outside of the framework model and compare it to the DOE Technical Targets. These models will be explained and exercised with existing hydrogen storage materials.« less

Image detection and compression for memory efficient system analysis

NASA Astrophysics Data System (ADS)

Bayraktar, Mustafa

2015-02-01

The advances in digital signal processing have been progressing towards efficient use of memory and processing. Both of these factors can be utilized efficiently by using feasible techniques of image storage by computing the minimum information of image which will enhance computation in later processes. Scale Invariant Feature Transform (SIFT) can be utilized to estimate and retrieve of an image. In computer vision, SIFT can be implemented to recognize the image by comparing its key features from SIFT saved key point descriptors. The main advantage of SIFT is that it doesn't only remove the redundant information from an image but also reduces the key points by matching their orientation and adding them together in different windows of image [1]. Another key property of this approach is that it works on highly contrasted images more efficiently because it`s design is based on collecting key points from the contrast shades of image.

Comparison of methods for estimating carbon dioxide storage by Sacramento's urban forest

Treesearch

Elena Aguaron; E. Gregory McPherson

2012-01-01

Limited open-grown urban tree species biomass equations have necessitated use of forest-derived equations with diverse conclusions on the accuracy of these equations to estimate urban biomass and carbon storage. Our goal was to determine and explain variability among estimates of CO2 storage from four sets of allometric equations for the same...

Carbon storage in Chinese grassland ecosystems: Influence of different integrative methods.

PubMed

Ma, Anna; He, Nianpeng; Yu, Guirui; Wen, Ding; Peng, Shunlei

2016-02-17

The accurate estimate of grassland carbon (C) is affected by many factors at the large scale. Here, we used six methods (three spatial interpolation methods and three grassland classification methods) to estimate C storage of Chinese grasslands based on published data from 2004 to 2014, and assessed the uncertainty resulting from different integrative methods. The uncertainty (coefficient of variation, CV, %) of grassland C storage was approximately 4.8% for the six methods tested, which was mainly determined by soil C storage. C density and C storage to the soil layer depth of 100 cm were estimated to be 8.46 ± 0.41 kg C m(-2) and 30.98 ± 1.25 Pg C, respectively. Ecosystem C storage was composed of 0.23 ± 0.01 (0.7%) above-ground biomass, 1.38 ± 0.14 (4.5%) below-ground biomass, and 29.37 ± 1.2 (94.8%) Pg C in the 0-100 cm soil layer. Carbon storage calculated by the grassland classification methods (18 grassland types) was closer to the mean value than those calculated by the spatial interpolation methods. Differences in integrative methods may partially explain the high uncertainty in C storage estimates in different studies. This first evaluation demonstrates the importance of multi-methodological approaches to accurately estimate C storage in large-scale terrestrial ecosystems.

A dynamic programming approach to estimate the capacity value of energy storage

DOE PAGES

Sioshansi, Ramteen; Madaeni, Seyed Hossein; Denholm, Paul

2013-09-17

Here, we present a method to estimate the capacity value of storage. Our method uses a dynamic program to model the effect of power system outages on the operation and state of charge of storage in subsequent periods. We combine the optimized dispatch from the dynamic program with estimated system loss of load probabilities to compute a probability distribution for the state of charge of storage in each period. This probability distribution can be used as a forced outage rate for storage in standard reliability-based capacity value estimation methods. Our proposed method has the advantage over existing approximations that itmore » explicitly captures the effect of system shortage events on the state of charge of storage in subsequent periods. We also use a numerical case study, based on five utility systems in the U.S., to demonstrate our technique and compare it to existing approximation methods.« less

An emulator for minimizing finite element analysis implementation resources

NASA Technical Reports Server (NTRS)

Melosh, R. J.; Utku, S.; Salama, M.; Islam, M.

1982-01-01

A finite element analysis emulator providing a basis for efficiently establishing an optimum computer implementation strategy when many calculations are involved is described. The SCOPE emulator determines computer resources required as a function of the structural model, structural load-deflection equation characteristics, the storage allocation plan, and computer hardware capabilities. Thereby, it provides data for trading analysis implementation options to arrive at a best strategy. The models contained in SCOPE lead to micro-operation computer counts of each finite element operation as well as overall computer resource cost estimates. Application of SCOPE to the Memphis-Arkansas bridge analysis provides measures of the accuracy of resource assessments. Data indicate that predictions are within 17.3 percent for calculation times and within 3.2 percent for peripheral storage resources for the ELAS code.

Influence of methane in CO2 transport and storage for CCS technology.

PubMed

Blanco, Sofía T; Rivas, Clara; Fernández, Javier; Artal, Manuela; Velasco, Inmaculada

2012-12-04

CO(2) Capture and Storage (CCS) is a good strategy to mitigate levels of atmospheric greenhouse gases. The type and quantity of impurities influence the properties and behavior of the anthropogenic CO(2), and so must be considered in the design and operation of CCS technology facilities. Their study is necessary for CO(2) transport and storage, and to develop theoretical models for specific engineering applications to CCS technology. In this work we determined the influence of CH(4), an important impurity of anthropogenic CO(2), within different steps of CCS technology: transport, injection, and geological storage. For this, we obtained new pressure-density-temperature (PρT) and vapor-liquid equilibrium (VLE) experimental data for six CO(2) + CH(4) mixtures at compositions which represent emissions from the main sources in the European Union and United States. The P and T ranges studied are within those estimated for CO(2) pipelines and geological storage sites. From these data we evaluated the minimal pressures for transport, regarding the density and pipeline's capacity requirements, and values for the solubility parameter of the mixtures, a factor which governs the solubility of substances present in the reservoir before injection. We concluded that the presence of CH(4) reduces the storage capacity and increases the buoyancy of the CO(2) plume, which diminishes the efficiency of solubility and residual trapping of CO(2), and reduces the injectivity into geological formations.

Comparison of Natural Gas Storage Estimates from the EIA and AGA

EIA Publications

1997-01-01

The Energy Information Administration (EIA) has been publishing monthly storage information for years. In order to address the need for more timely information, in 1994 the American Gas Association (AGA) began publishing weekly storage levels. Both the EIA and the AGA series provide estimates of the total working gas in storage, but use significantly different methodologies.

Carbon storage in forests and peatlands of Russia

Treesearch

V.A. Alexeyev; R.A. Birdsey; [Editors

1998-01-01

Contains information about carbon storage in the vegetation, soils, and peatlands of Russia. Estimates of carbon storage in forests are derived from statistical data from the 1988 national forest inventory of Russia and from other sources. Methods are presented for converting data on timber stock into phytomass of tree stands, and for estimating carbon storage in...

Consequences and mitigation of saltwater intrusion induced by short-circuiting during aquifer storage and recovery in a coastal subsurface

NASA Astrophysics Data System (ADS)

Gerardus Zuurbier, Koen; Stuyfzand, Pieter Jan

2017-02-01

Coastal aquifers and the deeper subsurface are increasingly exploited. The accompanying perforation of the subsurface for those purposes has increased the risk of short-circuiting of originally separated aquifers. This study shows how this short-circuiting negatively impacts the freshwater recovery efficiency (RE) during aquifer storage and recovery (ASR) in coastal aquifers. ASR was applied in a shallow saltwater aquifer overlying a deeper, confined saltwater aquifer, which was targeted for seasonal aquifer thermal energy storage (ATES). Although both aquifers were considered properly separated (i.e., a continuous clay layer prevented rapid groundwater flow between both aquifers), intrusion of deeper saltwater into the shallower aquifer quickly terminated the freshwater recovery. The presumable pathway was a nearby ATES borehole. This finding was supported by field measurements, hydrochemical analyses, and variable-density solute transport modeling (SEAWAT version 4; Langevin et al., 2007). The potentially rapid short-circuiting during storage and recovery can reduce the RE of ASR to null. When limited mixing with ambient groundwater is allowed, a linear RE decrease by short-circuiting with increasing distance from the ASR well within the radius of the injected ASR bubble was observed. Interception of deep short-circuiting water can mitigate the observed RE decrease, although complete compensation of the RE decrease will generally be unattainable. Brackish water upconing from the underlying aquitard towards the shallow recovery wells of the ASR system with multiple partially penetrating wells (MPPW-ASR) was observed. This leakage may lead to a lower recovery efficiency than based on current ASR performance estimations.

Carbon storage and carbon-to-organic matter relationships of three forested ecosystems of the Rocky Mountains

Treesearch

Theresa B. Jain

1994-01-01

Fluctuations in atmospheric carbon dioxide is influenced by carbon storage and cycling in terrestrial forest ecosystems. Currently, only gross estimates are available for carbon content of these ecosystems and reliable estimates are lacking for Rocky Mountain forests. To improve carbon storage estimates more information is needed on the relationship between carbon and...

Opportunities for increasing CO 2 storage in deep, saline formations by active reservoir management and treatment of extracted formation water: Case study at the GreenGen IGCC facility, Tianjin, PR China

DOE PAGES

Ziemkiewicz, Paul; Stauffer, Philip H.; Sullivan-Graham, Jeri; ...

2016-08-04

Carbon capture, utilization and storage (CCUS) seeks beneficial applications for CO 2 recovered from fossil fuel combustion. This study evaluated the potential for removing formation water to create additional storage capacity for CO 2, while simultaneously treating the produced water for beneficial use. Furthermore, the process would control pressures within the target formation, lessen the risk of caprock failure, and better control the movement of CO 2 within that formation. The project plans to highlight the method of using individual wells to produce formation water prior to injecting CO 2 as an efficient means of managing reservoir pressure. Because themore » pressure drawdown resulting from pre-injection formation water production will inversely correlate with pressure buildup resulting from CO 2 injection, it can be proactively used to estimate CO 2 storage capacity and to plan well-field operations. The project studied the GreenGen site in Tianjin, China where Huaneng Corporation is capturing CO 2 at a coal fired IGCC power plant. Known as the Tianjin Enhanced Water Recovery (EWR) project, local rock units were evaluated for CO 2 storage potential and produced water treatment options were then developed. Average treatment cost for produced water with a cooling water treatment goal ranged from 2.27 to 2.96 US$/m 3 (recovery 95.25%), and for a boiler water treatment goal ranged from 2.37 to 3.18 US$/m 3 (recovery 92.78%). Importance analysis indicated that water quality parameters and transportation are significant cost factors as the injection-extraction system is managed over time. Our study found that in a broad sense, active reservoir management in the context of CCUS/EWR is technically feasible. In addition, criteria for evaluating suitable vs. unsuitable reservoir properties, reservoir storage (caprock) integrity, a recommended injection/withdrawal strategy and cost estimates for water treatment and reservoir management are proposed.« less

Opportunities for increasing CO 2 storage in deep, saline formations by active reservoir management and treatment of extracted formation water: Case study at the GreenGen IGCC facility, Tianjin, PR China

DOE Office of Scientific and Technical Information (OSTI.GOV)

Ziemkiewicz, Paul; Stauffer, Philip H.; Sullivan-Graham, Jeri

Carbon capture, utilization and storage (CCUS) seeks beneficial applications for CO 2 recovered from fossil fuel combustion. This study evaluated the potential for removing formation water to create additional storage capacity for CO 2, while simultaneously treating the produced water for beneficial use. Furthermore, the process would control pressures within the target formation, lessen the risk of caprock failure, and better control the movement of CO 2 within that formation. The project plans to highlight the method of using individual wells to produce formation water prior to injecting CO 2 as an efficient means of managing reservoir pressure. Because themore » pressure drawdown resulting from pre-injection formation water production will inversely correlate with pressure buildup resulting from CO 2 injection, it can be proactively used to estimate CO 2 storage capacity and to plan well-field operations. The project studied the GreenGen site in Tianjin, China where Huaneng Corporation is capturing CO 2 at a coal fired IGCC power plant. Known as the Tianjin Enhanced Water Recovery (EWR) project, local rock units were evaluated for CO 2 storage potential and produced water treatment options were then developed. Average treatment cost for produced water with a cooling water treatment goal ranged from 2.27 to 2.96 US$/m 3 (recovery 95.25%), and for a boiler water treatment goal ranged from 2.37 to 3.18 US$/m 3 (recovery 92.78%). Importance analysis indicated that water quality parameters and transportation are significant cost factors as the injection-extraction system is managed over time. Our study found that in a broad sense, active reservoir management in the context of CCUS/EWR is technically feasible. In addition, criteria for evaluating suitable vs. unsuitable reservoir properties, reservoir storage (caprock) integrity, a recommended injection/withdrawal strategy and cost estimates for water treatment and reservoir management are proposed.« less

Control and Optimization of Electric Ship Propulsion Systems with Hybrid Energy Storage

NASA Astrophysics Data System (ADS)

Hou, Jun

Electric ships experience large propulsion-load fluctuations on their drive shaft due to encountered waves and the rotational motion of the propeller, affecting the reliability of the shipboard power network and causing wear and tear. This dissertation explores new solutions to address these fluctuations by integrating a hybrid energy storage system (HESS) and developing energy management strategies (EMS). Advanced electric propulsion drive concepts are developed to improve energy efficiency, performance and system reliability by integrating HESS, developing advanced control solutions and system integration strategies, and creating tools (including models and testbed) for design and optimization of hybrid electric drive systems. A ship dynamics model which captures the underlying physical behavior of the electric ship propulsion system is developed to support control development and system optimization. To evaluate the effectiveness of the proposed control approaches, a state-of-the-art testbed has been constructed which includes a system controller, Li-Ion battery and ultra-capacitor (UC) modules, a high-speed flywheel, electric motors with their power electronic drives, DC/DC converters, and rectifiers. The feasibility and effectiveness of HESS are investigated and analyzed. Two different HESS configurations, namely battery/UC (B/UC) and battery/flywheel (B/FW), are studied and analyzed to provide insights into the advantages and limitations of each configuration. Battery usage, loss analysis, and sensitivity to battery aging are also analyzed for each configuration. In order to enable real-time application and achieve desired performance, a model predictive control (MPC) approach is developed, where a state of charge (SOC) reference of flywheel for B/FW or UC for B/UC is used to address the limitations imposed by short predictive horizons, because the benefits of flywheel and UC working around high-efficiency range are ignored by short predictive horizons. Given the multi-frequency characteristics of load fluctuations, a filter-based control strategy is developed to illustrate the importance of the coordination within the HESS. Without proper control strategies, the HESS solution could be worse than a single energy storage system solution. The proposed HESS, when introduced into an existing shipboard electrical propulsion system, will interact with the power generation systems. A model-based analysis is performed to evaluate the interactions of the multiple power sources when a hybrid energy storage system is introduced. The study has revealed undesirable interactions when the controls are not coordinated properly, and leads to the conclusion that a proper EMS is needed. Knowledge of the propulsion-load torque is essential for the proposed system-level EMS, but this load torque is immeasurable in most marine applications. To address this issue, a model-based approach is developed so that load torque estimation and prediction can be incorporated into the MPC. In order to evaluate the effectiveness of the proposed approach, an input observer with linear prediction is developed as an alternative approach to obtain the load estimation and prediction. Comparative studies are performed to illustrate the importance of load torque estimation and prediction, and demonstrate the effectiveness of the proposed approach in terms of improved efficiency, enhanced reliability, and reduced wear and tear. Finally, the real-time MPC algorithm has been implemented on a physical testbed. Three different efforts have been made to enable real-time implementation: a specially tailored problem formulation, an efficient optimization algorithm and a multi-core hardware implementation. Compared to the filter-based strategy, the proposed real-time MPC achieves superior performance, in terms of the enhanced system reliability, improved HESS efficiency, and extended battery life.

A Comprehensive Study on Energy Efficiency and Performance of Flash-based SSD

DOE Office of Scientific and Technical Information (OSTI.GOV)

Park, Seon-Yeon; Kim, Youngjae; Urgaonkar, Bhuvan

2011-01-01

Use of flash memory as a storage medium is becoming popular in diverse computing environments. However, because of differences in interface, flash memory requires a hard-disk-emulation layer, called FTL (flash translation layer). Although the FTL enables flash memory storages to replace conventional hard disks, it induces significant computational and space overhead. Despite the low power consumption of flash memory, this overhead leads to significant power consumption in an overall storage system. In this paper, we analyze the characteristics of flash-based storage devices from the viewpoint of power consumption and energy efficiency by using various methodologies. First, we utilize simulation tomore » investigate the interior operation of flash-based storage of flash-based storages. Subsequently, we measure the performance and energy efficiency of commodity flash-based SSDs by using microbenchmarks to identify the block-device level characteristics and macrobenchmarks to reveal their filesystem level characteristics.« less

Concentrating Solar Power Projects - Crescent Dunes Solar Energy Project |

Science.gov Websites

: None Thermal Storage Storage Type: 2-tank direct Storage Capacity: 10 hours Thermal Storage Description : Thermal energy storage achieved by raising salt temperature from 550 to 1050 F. Thermal storage efficiency

Reversible Interconversion between 2,5-Dimethylpyrazine and 2,5-Dimethylpiperazine by Iridium-Catalyzed Hydrogenation/Dehydrogenation for Efficient Hydrogen Storage.

PubMed

Fujita, Ken-Ichi; Wada, Tomokatsu; Shiraishi, Takumi

2017-08-28

A new hydrogen storage system based on the hydrogenation and dehydrogenation of nitrogen heterocyclic compounds, employing a single iridium catalyst, has been developed. Efficient hydrogen storage using relatively small amounts of solvent compared with previous systems was achieved by this new system. Reversible transformations between 2,5-dimethylpyrazine and 2,5-dimethylpiperazine, accompanied by the uptake and release of three equivalents of hydrogen, could be repeated almost quantitatively at least four times without any loss of efficiency. Furthermore, hydrogen storage under solvent-free conditions was also accomplished. © 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

A quantitative assessment of groundwater resources in the Middle East and North Africa region

NASA Astrophysics Data System (ADS)

Lezzaik, Khalil; Milewski, Adam

2018-02-01

The Middle East and North Africa (MENA) region is the world's most water-stressed region, with its countries constituting 12 of the 15 most water-stressed countries globally. Because of data paucity, comprehensive regional-scale assessments of groundwater resources in the MENA region have been lacking. The presented study addresses this issue by using a distributed ArcGIS model, parametrized with gridded data sets, to estimate groundwater storage reserves in the region based on generated aquifer saturated thickness and effective porosity estimates. Furthermore, monthly gravimetric datasets (GRACE) and land surface parameters (GLDAS) were used to quantify changes in groundwater storage between 2003 and 2014. Total groundwater reserves in the region were estimated at 1.28 × 106 cubic kilometers (km3) with an uncertainty range between 816,000 and 1.93 × 106 km3. Most of the reserves are located within large sedimentary basins in North Africa and the Arabian Peninsula, with Algeria, Libya, Egypt, and Saudi Arabia accounting for approximately 75% of the region's total freshwater reserves. Alternatively, small groundwater reserves were found in fractured Precambrian basement exposures. As for groundwater changes between 2003 and 2014, all MENA countries except for Morocco exhibited declines in groundwater storage. However, given the region's large groundwater reserves, groundwater changes between 2003 and 2014 are minimal and represent no immediate short-term threat to the MENA region, with some exceptions. Notwithstanding this, the study recommends the development of sustainable and efficient groundwater management policies to optimally utilize the region's groundwater resources, especially in the face of climate change, demographic expansion, and socio-economic development.

A simple topography-driven, calibration-free runoff generation model

NASA Astrophysics Data System (ADS)

Gao, H.; Birkel, C.; Hrachowitz, M.; Tetzlaff, D.; Soulsby, C.; Savenije, H. H. G.

2017-12-01

Determining the amount of runoff generation from rainfall occupies a central place in rainfall-runoff modelling. Moreover, reading landscapes and developing calibration-free runoff generation models that adequately reflect land surface heterogeneities remains the focus of much hydrological research. In this study, we created a new method to estimate runoff generation - HAND-based Storage Capacity curve (HSC) which uses a topographic index (HAND, Height Above the Nearest Drainage) to identify hydrological similarity and partially the saturated areas of catchments. We then coupled the HSC model with the Mass Curve Technique (MCT) method to estimate root zone storage capacity (SuMax), and obtained the calibration-free runoff generation model HSC-MCT. Both the two models (HSC and HSC-MCT) allow us to estimate runoff generation and simultaneously visualize the spatial dynamic of saturated area. We tested the two models in the data-rich Bruntland Burn (BB) experimental catchment in Scotland with an unusual time series of the field-mapped saturation area extent. The models were subsequently tested in 323 MOPEX (Model Parameter Estimation Experiment) catchments in the United States. HBV and TOPMODEL were used as benchmarks. We found that the HSC performed better in reproducing the spatio-temporal pattern of the observed saturated areas in the BB catchment compared with TOPMODEL which is based on the topographic wetness index (TWI). The HSC also outperformed HBV and TOPMODEL in the MOPEX catchments for both calibration and validation. Despite having no calibrated parameters, the HSC-MCT model also performed comparably well with the calibrated HBV and TOPMODEL, highlighting the robustness of the HSC model to both describe the spatial distribution of the root zone storage capacity and the efficiency of the MCT method to estimate the SuMax. Moreover, the HSC-MCT model facilitated effective visualization of the saturated area, which has the potential to be used for broader geoscience studies beyond hydrology.

Assessing Carbon Storage and Sequestration of Seagrass Meadows on the Pacific Coast of Canada

NASA Astrophysics Data System (ADS)

Postlethwaite, V. R.; McGowan, A. E.; Robinson, C.; Kohfeld, K. E.; Pellatt, M. G.; Yakimishyn, J.; Chastain, S. G.

2016-12-01

Recent estimates suggest that seagrasses are highly efficient carbon sinks, storing a disproportionate amount of carbon for their relatively small area (only approximately 0.2% of the global ocean), and that they may bury carbon up to 12 times faster than terrestrial forests. Unfortunately, seagrass meadows are being lost at a rate of 0.4-2.6% yr-1, potentially releasing 0.15-1.02 Pg (billion tonnes) carbon dioxide into the atmosphere annually. Research on seagrass carbon stocks has been mainly limited to areas in the Mediterranean, Southeast Asia, and Western Australia, and specifically has been very limited in the Northeast Pacific. We aim to characterize the carbon storage and sequestration occurring in the Pacific Rim National Park Reserve and the Clayoquot Sound area, off the western coast of Vancouver Island, British Columbia (BC). Each of our sites varied in environmental characteristics representative of BC's seagrass meadows, including freshwater influence. Six cores, plus one from a "reference" site were taken from each meadow. Loss on ignition (LOI) and elemental analysis will be used to determine organic C and carbonate content. Additionally, we will use dry bulk density, 210Pb dating and seagrass density data to determine carbon accumulation rates and total meadow carbon stocks to provide a comprehensive picture of carbon storage and sequestration in BC's seagrass meadows. Carbon storage results will contribute to global estimates of seagrass carbon stocks via the Commission for Environmental Cooperation, as well as assist in marine ecosystem conservation planning and help in understanding the value of these ecosystems, especially as a means of climate change mitigation.

Potential Water Availability Index (PWAI): A New Water Vulnerability Index for Africa Based on GRACE Data

NASA Astrophysics Data System (ADS)

Hasan, E.; Tarhule, A.; Hong, Y.; Moore, B., III

2016-12-01

The critical role of water in enabling or constraining human wellbeing and socio-economic activities has led to interest in quantitatively establishing the status or index of water (in)sufficiency over time and space. Introduced in 1989, the first widely accepted index expressed the status of water resources availability in terms of vulnerability, stress, or scarcity. Since then, numerous refinements and modifications to the concept have been published but nearly all adopt the same basic formulation; water status is a function of available water resources and demand or use. However, accurately defining and assessing `available water' has proved problematic especially in data scarce regions, such as Africa. In this paper, we use Total Water Storage (TWS) estimated from NASA's Gravity Recovery and Climate Experiment (GRACE) in lieu of observational hydrologic data, to estimate the Water Scarcity Index (WSI) for Africa at country level. The monthly TWS Positive anomalies represent periods of net system recharge while negative anomalies represent net system loss due to evapotranspiration and anthropogenic withdrawals. The procedure is as follows. First, we calculated the long-term (2002-2014) Internal Water Storage (IWS) for each country using the monthly precipitation data from the Global Precipitation Climatology Centre (GPCC). Next, the yearly cumulative positive and negative anomalies were added to the long-term IWS to obtain volumetric Potential Water Storage (VPWS) per country. By dividing VPWS by population, we obtain estimates of per capita water availability which can be grouped into vulnerability classes using established thresholds. Our VPWS showed very high correlation (R2 =0.94, p=0.0001) with the values of Internal Renewable Water Resources (IRWR) estimated by AQUSTAT. Additionally, the GWSI is highly correlated (R2 =0.94, p=0.0001) with the existing WSI index from the world bank data center. The novelty and contribution of our approach is in using GRACE anomalies to efficiently estimate total available water, including groundwater which is at best poorly estimated and, frequently, completely ignored in conventional approaches due to absent or unreliable data. The available water estimated in this way represent the potential amount of water that could be theoretically exploited.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Namhata, Argha; Oladyshkin, Sergey; Dilmore, Rober

Carbon dioxide (CO2) storage into geological formations is regarded as an important mitigation strategy for anthropogenic CO2 emissions to the atmosphere. This study first simulates the leakage of CO2 and brine from a storage reservoir through the caprock. Then, we estimate the resulting pressure changes at the zone overlying the caprock also known as Above Zone Monitoring Interval (AZMI). A data-driven approach of arbitrary Polynomial Chaos (aPC) Expansion is then used to quantify the uncertainty in the above zone pressure prediction based on the uncertainties in different geologic parameters. Finally, a global sensitivity analysis is performed with Sobol indices basedmore » on the aPC technique to determine the relative importance of different parameters on pressure prediction. The results indicate that there can be uncertainty in pressure prediction locally around the leakage zones. The degree of such uncertainty in prediction depends on the quality of site specific information available for analysis. The scientific results from this study provide substantial insight that there is a need for site-specific data for efficient predictions of risks associated with storage activities. The presented approach can provide a basis of optimized pressure based monitoring network design at carbon storage sites.« less

Design tool for estimating chemical hydrogen storage system characteristics for light-duty fuel cell vehicles

DOE PAGES

Brooks, Kriston P.; Sprik, Samuel J.; Tamburello, David A.; ...

2018-04-07

The U.S. Department of Energy (DOE) developed a vehicle Framework model to simulate fuel cell-based light-duty vehicle operation for various hydrogen storage systems. This transient model simulates the performance of the storage system, fuel cell, and vehicle for comparison to Technical Targets established by DOE for four drive cycles/profiles. Chemical hydrogen storage models have been developed for the Framework for both exothermic and endothermic materials. Despite the utility of such models, they require that material researchers input system design specifications that cannot be estimated easily. To address this challenge, a design tool has been developed that allows researchers to directlymore » enter kinetic and thermodynamic chemical hydrogen storage material properties into a simple sizing module that then estimates system parameters required to run the storage system model. Additionally, the design tool can be used as a standalone executable file to estimate the storage system mass and volume outside of the Framework model. Here, these models will be explained and exercised with the representative hydrogen storage materials exothermic ammonia borane (NH 3BH 3) and endothermic alane (AlH 3).« less

Design tool for estimating chemical hydrogen storage system characteristics for light-duty fuel cell vehicles

DOE Office of Scientific and Technical Information (OSTI.GOV)

Brooks, Kriston P.; Sprik, Samuel J.; Tamburello, David A.

The U.S. Department of Energy (DOE) developed a vehicle Framework model to simulate fuel cell-based light-duty vehicle operation for various hydrogen storage systems. This transient model simulates the performance of the storage system, fuel cell, and vehicle for comparison to Technical Targets established by DOE for four drive cycles/profiles. Chemical hydrogen storage models have been developed for the Framework for both exothermic and endothermic materials. Despite the utility of such models, they require that material researchers input system design specifications that cannot be estimated easily. To address this challenge, a design tool has been developed that allows researchers to directlymore » enter kinetic and thermodynamic chemical hydrogen storage material properties into a simple sizing module that then estimates system parameters required to run the storage system model. Additionally, the design tool can be used as a standalone executable file to estimate the storage system mass and volume outside of the Framework model. Here, these models will be explained and exercised with the representative hydrogen storage materials exothermic ammonia borane (NH 3BH 3) and endothermic alane (AlH 3).« less

Large temporal scale and capacity subsurface bulk energy storage with CO2

NASA Astrophysics Data System (ADS)

Saar, M. O.; Fleming, M. R.; Adams, B. M.; Ogland-Hand, J.; Nelson, E. S.; Randolph, J.; Sioshansi, R.; Kuehn, T. H.; Buscheck, T. A.; Bielicki, J. M.

2017-12-01

Decarbonizing energy systems by increasing the penetration of variable renewable energy (VRE) technologies requires efficient and short- to long-term energy storage. Very large amounts of energy can be stored in the subsurface as heat and/or pressure energy in order to provide both short- and long-term (seasonal) storage, depending on the implementation. This energy storage approach can be quite efficient, especially where geothermal energy is naturally added to the system. Here, we present subsurface heat and/or pressure energy storage with supercritical carbon dioxide (CO2) and discuss the system's efficiency, deployment options, as well as its advantages and disadvantages, compared to several other energy storage options. CO2-based subsurface bulk energy storage has the potential to be particularly efficient and large-scale, both temporally (i.e., seasonal) and spatially. The latter refers to the amount of energy that can be stored underground, using CO2, at a geologically conducive location, potentially enabling storing excess power from a substantial portion of the power grid. The implication is that it would be possible to employ centralized energy storage for (a substantial part of) the power grid, where the geology enables CO2-based bulk subsurface energy storage, whereas the VRE technologies (solar, wind) are located on that same power grid, where (solar, wind) conditions are ideal. However, this may require reinforcing the power grid's transmission lines in certain parts of the grid to enable high-load power transmission from/to a few locations.

Design and Verification of Remote Sensing Image Data Center Storage Architecture Based on Hadoop

NASA Astrophysics Data System (ADS)

Tang, D.; Zhou, X.; Jing, Y.; Cong, W.; Li, C.

2018-04-01

The data center is a new concept of data processing and application proposed in recent years. It is a new method of processing technologies based on data, parallel computing, and compatibility with different hardware clusters. While optimizing the data storage management structure, it fully utilizes cluster resource computing nodes and improves the efficiency of data parallel application. This paper used mature Hadoop technology to build a large-scale distributed image management architecture for remote sensing imagery. Using MapReduce parallel processing technology, it called many computing nodes to process image storage blocks and pyramids in the background to improve the efficiency of image reading and application and sovled the need for concurrent multi-user high-speed access to remotely sensed data. It verified the rationality, reliability and superiority of the system design by testing the storage efficiency of different image data and multi-users and analyzing the distributed storage architecture to improve the application efficiency of remote sensing images through building an actual Hadoop service system.

CO2 storage capacity estimation: Methodology and gaps

USGS Publications Warehouse

Bachu, S.; Bonijoly, D.; Bradshaw, J.; Burruss, R.; Holloway, S.; Christensen, N.P.; Mathiassen, O.M.

2007-01-01

Implementation of CO2 capture and geological storage (CCGS) technology at the scale needed to achieve a significant and meaningful reduction in CO2 emissions requires knowledge of the available CO2 storage capacity. CO2 storage capacity assessments may be conducted at various scales-in decreasing order of size and increasing order of resolution: country, basin, regional, local and site-specific. Estimation of the CO2 storage capacity in depleted oil and gas reservoirs is straightforward and is based on recoverable reserves, reservoir properties and in situ CO2 characteristics. In the case of CO2-EOR, the CO2 storage capacity can be roughly evaluated on the basis of worldwide field experience or more accurately through numerical simulations. Determination of the theoretical CO2 storage capacity in coal beds is based on coal thickness and CO2 adsorption isotherms, and recovery and completion factors. Evaluation of the CO2 storage capacity in deep saline aquifers is very complex because four trapping mechanisms that act at different rates are involved and, at times, all mechanisms may be operating simultaneously. The level of detail and resolution required in the data make reliable and accurate estimation of CO2 storage capacity in deep saline aquifers practical only at the local and site-specific scales. This paper follows a previous one on issues and development of standards for CO2 storage capacity estimation, and provides a clear set of definitions and methodologies for the assessment of CO2 storage capacity in geological media. Notwithstanding the defined methodologies suggested for estimating CO2 storage capacity, major challenges lie ahead because of lack of data, particularly for coal beds and deep saline aquifers, lack of knowledge about the coefficients that reduce storage capacity from theoretical to effective and to practical, and lack of knowledge about the interplay between various trapping mechanisms at work in deep saline aquifers. ?? 2007 Elsevier Ltd. All rights reserved.

Engineering the Implementation of Pumped Hydro Energy Storage in the Arizona Power Grid

NASA Astrophysics Data System (ADS)

Dixon, William Jesse J.

This thesis addresses the issue of making an economic case for bulk energy storage in the Arizona bulk power system. Pumped hydro energy storage (PHES) is used in this study. Bulk energy storage has often been suggested for large scale electric power systems in order to levelize load (store energy when it is inexpensive [energy demand is low] and discharge energy when it is expensive [energy demand is high]). It also has the potential to provide opportunities to avoid transmission and generation expansion, and provide for generation reserve margins. As the level of renewable energy resources increases, the uncertainty and variability of wind and solar resources may be improved by bulk energy storage technologies. For this study, the MATLab software platform is used, a mathematical based modeling language, optimization solvers (specifically Gurobi), and a power flow solver (PowerWorld) are used to simulate an economic dispatch problem that includes energy storage and transmission losses. A program is created which utilizes quadratic programming to analyze various cases using a 2010 summer peak load from the Arizona portion of the Western Electricity Coordinating Council (WECC) system. Actual data from industry are used in this test bed. In this thesis, the full capabilities of Gurobi are not utilized (e.g., integer variables, binary variables). However, the formulation shown here does create a platform such that future, more sophisticated modeling may readily be incorporated. The developed software is used to assess the Arizona test bed with a low level of energy storage to study how the storage power limit effects several optimization outputs such as the system wide operating costs. Large levels of energy storage are then added to see how high level energy storage affects peak shaving, load factor, and other system applications. Finally, various constraint relaxations are made to analyze why the applications tested eventually approach a constant value. This research illustrates the use of energy storage which helps minimize the system wide generator operating cost by "shaving" energy off of the peak demand. The thesis builds on the work of another recent researcher with the objectives of strengthening the assumptions used, checking the solutions obtained, utilizing higher level simulation languages to affirm results, and expanding the results and conclusions. One important point not fully discussed in the present thesis is the impact of efficiency in the pumped hydro cycle. The efficiency of the cycle for modern units is estimated at higher than 90%. Inclusion of pumped hydro losses is relegated to future work.

Dissolved Nutrient Retention Dynamics in River Networks: A Modeling Investigation of Transient Flow and Scale Effects

DOE Office of Scientific and Technical Information (OSTI.GOV)

Ye, Sheng; Covino, Timothy P.; Sivapalan, Murugesu

In this paper, we use a dynamic network flow model, coupled with a transient storage zone biogeochemical model, to simulate dissolved nutrient removal processes at the channel network scale. We have explored several scenarios in respect of the combination of rainfall variability, and the biological and geomorphic characteristics of the catchment, to understand the dominant controls on removal and delivery of dissolved nutrients (e.g., nitrate). These model-based theoretical analyses suggested that while nutrient removal efficiency is lower during flood events compared to during baseflow periods, flood events contribute significantly to bulk nutrient removal, whereas bulk removal during baseflow periods ismore » less. This is due to the fact that nutrient supply is larger during flood events; this trend is even stronger in large rivers. However, the efficiency of removal during both periods decreases in larger rivers, however, due to (i) increasing flow velocities and thus decreasing residence time, and (ii) increasing flow depth, and thus decreasing nutrient uptake rates. Besides nutrient removal processes can be divided into two parts: in the main channel and in the hyporheic transient storage zone. When assessing their relative contributions the size of the transient storage zone is a dominant control, followed by uptake rates in the main channel and in the transient storage zone. Increasing size of the transient storage zone with downstream distance affects the relative contributions to nutrient removal of the water column and the transient storage zone, which also impacts the way nutrient removal rates scale with increasing size of rivers. Intra-annual hydrologic variability has a significant impact on removal rates at all scales: the more variable the streamflow is, compared to mean discharge, the less nutrient is removed in the channel network. A scale-independent first order uptake coefficient, ke, estimated from model simulations, is highly dependent on the relative size of the transient storage zone and how it changes in the downstream direction, as well as the nature of hydrologic variability.« less

Effects of reduction in porosity and permeability with depth on storage capacity and injectivity in deep saline aquifers: A case study from the Mount Simon Sandstone aquifer

USGS Publications Warehouse

Medina, C.R.; Rupp, J.A.; Barnes, D.A.

2011-01-01

The Upper Cambrian Mount Simon Sandstone is recognized as a deep saline reservoir that has significant potential for geological sequestration in the Midwestern region of the United States. Porosity and permeability values collected from core analyses in rocks from this formation and its lateral equivalents in Indiana, Kentucky, Michigan, and Ohio indicate a predictable relationship with depth owing to a reduction in the pore structure due to the effects of compaction and/or cementation, primarily as quartz overgrowths. The regional trend of decreasing porosity with depth is described by the equation: ??(d)=16.36??e-0.00039*d, where ?? is the porosity and d is the depth in m. The decrease of porosity with depth generally holds true on a basinwide scale. Bearing in mind local variations in lithologic and petrophysical character within the Mount Simon Sandstone, the source data that were used to predict porosity were utilized to estimate the pore volume available within the reservoir that could potentially serve as storage space for injected CO2. The potential storage capacity estimated for the Mount Simon Sandstone in the study area, using efficiency factors of 1%, 5%, 10%, and 15%, is 23,680, 118,418, 236,832, and 355,242 million metric tons of CO2, respectively. ?? 2010 Elsevier Ltd.

A power management circuit with 50% efficiency and large load capacity for triboelectric nanogenerator

NASA Astrophysics Data System (ADS)

Bao, Dechun; Luo, Lichuan; Zhang, Zhaohua; Ren, Tianling

2017-09-01

Recently, triboelectric nanogenerators (TENGs), as a collection technology with characteristics of high reliability, high energy density and low cost, has attracted more and more attention. However, the energy coming from TENGs needs to be stored in a storage unit effectively due to its unstable ac output. The traditional energy storage circuit has an extremely low energy storage efficiency for TENGs because of their high internal impedance. This paper presents a new power management circuit used to optimize the energy using efficiency of TENGs, and realize large load capacity. The power management circuit mainly includes rectification storage circuit and DC-DC management circuit. A rotating TENG with maximal energy output of 106 mW at 170 rpm based on PCB is used for the experimental verification. Experimental results show that the power energy transforming to the storage capacitor reach up to 53 mW and the energy using efficiency is calculated as 50%. When different loading resistances range from 0.82 to 34.5 k {{Ω }} are connected to the storage capacitor in parallel, the power energy stored in the storage capacitor is all about 52.5 mW. Getting through the circuit, the power energy coming from the TENGs can be used to drive numerous conventional electronics, such as wearable watches.

Integration of Decentralized Thermal Storages Within District Heating (DH) Networks

NASA Astrophysics Data System (ADS)

Schuchardt, Georg K.

2016-12-01

Thermal Storages and Thermal Accumulators are an important component within District Heating (DH) systems, adding flexibility and offering additional business opportunities for these systems. Furthermore, these components have a major impact on the energy and exergy efficiency as well as the heat losses of the heat distribution system. Especially the integration of Thermal Storages within ill-conditioned parts of the overall DH system enhances the efficiency of the heat distribution. Regarding an illustrative and simplified example for a DH system, the interactions of different heat storage concepts (centralized and decentralized) and the heat losses, energy and exergy efficiencies will be examined by considering the thermal state of the heat distribution network.

A Secure and Efficient Audit Mechanism for Dynamic Shared Data in Cloud Storage

PubMed Central

2014-01-01

With popularization of cloud services, multiple users easily share and update their data through cloud storage. For data integrity and consistency in the cloud storage, the audit mechanisms were proposed. However, existing approaches have some security vulnerabilities and require a lot of computational overheads. This paper proposes a secure and efficient audit mechanism for dynamic shared data in cloud storage. The proposed scheme prevents a malicious cloud service provider from deceiving an auditor. Moreover, it devises a new index table management method and reduces the auditing cost by employing less complex operations. We prove the resistance against some attacks and show less computation cost and shorter time for auditing when compared with conventional approaches. The results present that the proposed scheme is secure and efficient for cloud storage services managing dynamic shared data. PMID:24959630

Effective energy storage from a triboelectric nanogenerator.

PubMed

Zi, Yunlong; Wang, Jie; Wang, Sihong; Li, Shengming; Wen, Zhen; Guo, Hengyu; Wang, Zhong Lin

2016-03-11

To sustainably power electronics by harvesting mechanical energy using nanogenerators, energy storage is essential to supply a regulated and stable electric output, which is traditionally realized by a direct connection between the two components through a rectifier. However, this may lead to low energy-storage efficiency. Here, we rationally design a charging cycle to maximize energy-storage efficiency by modulating the charge flow in the system, which is demonstrated on a triboelectric nanogenerator by adding a motion-triggered switch. Both theoretical and experimental comparisons show that the designed charging cycle can enhance the charging rate, improve the maximum energy-storage efficiency by up to 50% and promote the saturation voltage by at least a factor of two. This represents a progress to effectively store the energy harvested by nanogenerators with the aim to utilize ambient mechanical energy to drive portable/wearable/implantable electronics.

A secure and efficient audit mechanism for dynamic shared data in cloud storage.

PubMed

Kwon, Ohmin; Koo, Dongyoung; Shin, Yongjoo; Yoon, Hyunsoo

2014-01-01

With popularization of cloud services, multiple users easily share and update their data through cloud storage. For data integrity and consistency in the cloud storage, the audit mechanisms were proposed. However, existing approaches have some security vulnerabilities and require a lot of computational overheads. This paper proposes a secure and efficient audit mechanism for dynamic shared data in cloud storage. The proposed scheme prevents a malicious cloud service provider from deceiving an auditor. Moreover, it devises a new index table management method and reduces the auditing cost by employing less complex operations. We prove the resistance against some attacks and show less computation cost and shorter time for auditing when compared with conventional approaches. The results present that the proposed scheme is secure and efficient for cloud storage services managing dynamic shared data.

Effective energy storage from a triboelectric nanogenerator

NASA Astrophysics Data System (ADS)

Zi, Yunlong; Wang, Jie; Wang, Sihong; Li, Shengming; Wen, Zhen; Guo, Hengyu; Wang, Zhong Lin

2016-03-01

To sustainably power electronics by harvesting mechanical energy using nanogenerators, energy storage is essential to supply a regulated and stable electric output, which is traditionally realized by a direct connection between the two components through a rectifier. However, this may lead to low energy-storage efficiency. Here, we rationally design a charging cycle to maximize energy-storage efficiency by modulating the charge flow in the system, which is demonstrated on a triboelectric nanogenerator by adding a motion-triggered switch. Both theoretical and experimental comparisons show that the designed charging cycle can enhance the charging rate, improve the maximum energy-storage efficiency by up to 50% and promote the saturation voltage by at least a factor of two. This represents a progress to effectively store the energy harvested by nanogenerators with the aim to utilize ambient mechanical energy to drive portable/wearable/implantable electronics.

Emissions impacts and benefits of plug-in hybrid electric vehicles and vehicle-to-grid services

DOE PAGES

Sioshansi, Ramteen; Denholm, Paul

2009-01-22

Plug-in hybrid electric vehicles (PHEVs) have been promoted as a potential technology to reduce emissions of greenhouse gases and other pollutants by using electricity instead of petroleum, and by improving electric system efficiency by providing vehicle-to-grid (V2G) services. We use an electric power system model to explicitly evaluate the change in generator dispatches resulting from PHEV deployment in the Texas grid, and apply fixed and non-parametric estimates of generator emissions rates, to estimate the resulting changes in generation emissions. Here, we find that by using the flexibility of when vehicles may be charged, generator efficiency can be increased substantially. Bymore » changing generator dispatch, a PHEV fleet of up to 15% of light-duty vehicles can actually decrease net generator NO x emissions during the ozone season, despite the additional charging load. By adding V2G services, such as spinning reserves and energy storage, CO 2, SO 2, and NO x emissions can be reduced even further.« less

Emissions impacts and benefits of plug-in hybrid electric vehicles and vehicle-to-grid services.

PubMed

Sioshansi, Ramteen; Denholm, Paul

2009-02-15

Plug-in hybrid electric vehicles (PHEVs) have been promoted as a potential technology to reduce emissions of greenhouse gases and other pollutants by using electricity instead of petroleum, and byimproving electric system efficiency by providing vehicle-to-grid (V2G) services. We use an electric power system model to explicitly evaluate the change in generator dispatches resulting from PHEV deployment in the Texas grid, and apply fixed and non-parametric estimates of generator emissions rates, to estimate the resulting changes in generation emissions. We find that by using the flexibility of when vehicles may be charged, generator efficiency can be increased substantially. By changing generator dispatch, a PHEVfleet of up to 15% of light-duty vehicles can actually decrease net generator NOx emissions during the ozone season, despite the additional charging load. By adding V2G services, such as spinning reserves and energy storage, CO2, SO2, and NOx emissions can be reduced even further.

Power-to-heat in adiabatic compressed air energy storage power plants for cost reduction and increased flexibility

NASA Astrophysics Data System (ADS)

Dreißigacker, Volker

2018-04-01

The development of new technologies for large-scale electricity storage is a key element in future flexible electricity transmission systems. Electricity storage in adiabatic compressed air energy storage (A-CAES) power plants offers the prospect of making a substantial contribution to reach this goal. This concept allows efficient, local zero-emission electricity storage on the basis of compressed air in underground caverns. The compression and expansion of air in turbomachinery help to balance power generation peaks that are not demand-driven on the one hand and consumption-induced load peaks on the other. For further improvements in cost efficiencies and flexibility, system modifications are necessary. Therefore, a novel concept regarding the integration of an electrical heating component is investigated. This modification allows increased power plant flexibilities and decreasing component sizes due to the generated high temperature heat with simultaneously decreasing total round trip efficiencies. For an exemplarily A-CAES case simulation studies regarding the electrical heating power and thermal energy storage sizes were conducted to identify the potentials in cost reduction of the central power plant components and the loss in round trip efficiency.

Spatial and Temporal Influences on Carbon Storage in Hydric Soils of the Conterminous United States

NASA Astrophysics Data System (ADS)

Sundquist, E. T.; Ackerman, K.; Bliss, N.; Griffin, R.; Waltman, S.; Windham-Myers, L.

2016-12-01

Defined features of hydric soils persist over extensive areas of the conterminous United States (CUS) long after their hydric formation conditions have been altered by historical changes in land and water management. These legacy hydric features may represent previous wetland environments in which soil carbon storage was significantly higher before the influence of human activities. We hypothesize that historical alterations of hydric soil carbon storage can be approximated using carefully selected estimates of carbon storage in currently identified hydric soils. Using the Soil Survey Geographic (SSURGO) database, we evaluate carbon storage in identified hydric soil components that are subject to discrete ranges of current or recent conditions of flooding, ponding, and other indicators of hydric and non-hydric soil associations. We check our evaluations and, where necessary, adjust them using independently published soil data. We compare estimates of soil carbon storage under various hydric and non-hydric conditions within proximal landscapes and similar biophysical settings and ecosystems. By combining these setting- and ecosystem-constrained comparisons with the spatial distribution and attributes of wetlands in the National Wetlands Inventory, we impute carbon storage estimates for soils that occur in current wetlands and for hydric soils that are not associated with current wetlands. Using historical data on land use and water control structures, we map the spatial and temporal distribution of past changes in land and water management that have affected hydric soils. We combine these maps with our imputed carbon storage estimates to calculate ranges of values for historical and present-day carbon storage in hydric soils throughout the CUS. These estimates may provide useful constraints for projections of potential carbon storage in hydric soils under future conditions.

Monitoring Reservoir Storage in South Asia from Satellite Remote Sensing

NASA Astrophysics Data System (ADS)

Zhang, S.; Gao, H.; Naz, B.

2013-12-01

Realtime reservoir storage information is essential for accurate flood monitoring and prediction in South Asia, where the fatality rate (by area) due to floods is among the highest in the world. However, South Asia is dominated by international river basins where communications among neighboring countries about reservoir storage and management are extremely limited. In this study, we use a suite of NASA satellite observations to achieve high quality estimation of reservoir storage and storage variations at near realtime in South Asia. The monitoring approach employs vegetation indices from the Moderate Resolution Imaging Spectroradiometer (MODIS) 16-day 250 m MOD13Q1 product and the surface elevation data from the Geoscience Laser Altimeter System (GLAS) on board the Ice, Cloud and land Elevation Satellite (ICESat). This approach contains four steps: 1) identifying the reservoirs with ICESat GLAS overpasses and extracting the elevation data for these locations; 2) using the K-means method for water classification from MODIS andapplying a novel post-classification algorithm to enhance water area estimation accuracy; 3) deriving the relationship between the MODIS water surface area and the ICESat elevation; and 4) estimating the storage of reservoirs over time based on the elevation-area relationship and the MODIS water area time series. For evaluation purposes, we compared the satellite-based reservoir storage with gauge observations for 16 reservoirs in South Asia. The storage estimates were highly correlated with observations (R = 0.92 to 0.98), with values for the normalized root mean square error (NRMSE) ranging from 8.7% to 25.2%. Using this approach, storage and storage variations were estimated for 16 South Asia reservoirs from 2000 to 2012.

Edge-Based Efficient Search over Encrypted Data Mobile Cloud Storage

PubMed Central

Liu, Fang; Cai, Zhiping; Xiao, Nong; Zhao, Ziming

2018-01-01

Smart sensor-equipped mobile devices sense, collect, and process data generated by the edge network to achieve intelligent control, but such mobile devices usually have limited storage and computing resources. Mobile cloud storage provides a promising solution owing to its rich storage resources, great accessibility, and low cost. But it also brings a risk of information leakage. The encryption of sensitive data is the basic step to resist the risk. However, deploying a high complexity encryption and decryption algorithm on mobile devices will greatly increase the burden of terminal operation and the difficulty to implement the necessary privacy protection algorithm. In this paper, we propose ENSURE (EfficieNt and SecURE), an efficient and secure encrypted search architecture over mobile cloud storage. ENSURE is inspired by edge computing. It allows mobile devices to offload the computation intensive task onto the edge server to achieve a high efficiency. Besides, to protect data security, it reduces the information acquisition of untrusted cloud by hiding the relevance between query keyword and search results from the cloud. Experiments on a real data set show that ENSURE reduces the computation time by 15% to 49% and saves the energy consumption by 38% to 69% per query. PMID:29652810

Edge-Based Efficient Search over Encrypted Data Mobile Cloud Storage.

PubMed

Guo, Yeting; Liu, Fang; Cai, Zhiping; Xiao, Nong; Zhao, Ziming

2018-04-13

Smart sensor-equipped mobile devices sense, collect, and process data generated by the edge network to achieve intelligent control, but such mobile devices usually have limited storage and computing resources. Mobile cloud storage provides a promising solution owing to its rich storage resources, great accessibility, and low cost. But it also brings a risk of information leakage. The encryption of sensitive data is the basic step to resist the risk. However, deploying a high complexity encryption and decryption algorithm on mobile devices will greatly increase the burden of terminal operation and the difficulty to implement the necessary privacy protection algorithm. In this paper, we propose ENSURE (EfficieNt and SecURE), an efficient and secure encrypted search architecture over mobile cloud storage. ENSURE is inspired by edge computing. It allows mobile devices to offload the computation intensive task onto the edge server to achieve a high efficiency. Besides, to protect data security, it reduces the information acquisition of untrusted cloud by hiding the relevance between query keyword and search results from the cloud. Experiments on a real data set show that ENSURE reduces the computation time by 15% to 49% and saves the energy consumption by 38% to 69% per query.

Prospects for hydrogen storage in graphene.

PubMed

Tozzini, Valentina; Pellegrini, Vittorio

2013-01-07

Hydrogen-based fuel cells are promising solutions for the efficient and clean delivery of electricity. Since hydrogen is an energy carrier, a key step for the development of a reliable hydrogen-based technology requires solving the issue of storage and transport of hydrogen. Several proposals based on the design of advanced materials such as metal hydrides and carbon structures have been made to overcome the limitations of the conventional solution of compressing or liquefying hydrogen in tanks. Nevertheless none of these systems are currently offering the required performances in terms of hydrogen storage capacity and control of adsorption/desorption processes. Therefore the problem of hydrogen storage remains so far unsolved and it continues to represent a significant bottleneck to the advancement and proliferation of fuel cell and hydrogen technologies. Recently, however, several studies on graphene, the one-atom-thick membrane of carbon atoms packed in a honeycomb lattice, have highlighted the potentialities of this material for hydrogen storage and raise new hopes for the development of an efficient solid-state hydrogen storage device. Here we review on-going efforts and studies on functionalized and nanostructured graphene for hydrogen storage and suggest possible developments for efficient storage/release of hydrogen under ambient conditions.

Steam engine research for solar parabolic dish

NASA Technical Reports Server (NTRS)

Demler, R. L.

1981-01-01

The parabolic dish solar concentrator provides an opportunity to generate high grade energy in a modular system. Most of the capital is projected to be in the dish and its installation. Assurance of a high production demand of a standard dish could lead to dramatic cost reductions. High production volume in turn depends upon maximum application flexibility by providing energy output options, e.g., heat, electricity, chemicals and combinations thereof. Subsets of these options include energy storage and combustion assist. A steam engine design and experimental program is described which investigate the efficiency potential of a small 25 kW compound reheat cycle piston engine. An engine efficiency of 35 percent is estimated for a 700 C steam temperature from the solar receiver.

Moisture buffer capacity of cement-lime plasters with enhanced thermal storage capacity

NASA Astrophysics Data System (ADS)

Fořt, Jan; Pavlíková, Milena; Pavlík, Zbyšek

2017-07-01

Indoor air temperature and relative humidity represent important parameters for health and working efficiency of buildings occupants. Beside the moderation of temperature, investigation of hygric properties of building materials with connection to indoor relative humidity variation became recognized as a relevant factor for energy efficient building maintenance. The moisture buffer value introduced in the Nordtest protocol can be used for estimation of moisture buffer capacity of building materials or their multi-layered systems. In this paper, both the ideal and real moisture buffer values are examined on the basis of simulation of diurnal relative humidity fluctuations in plasters with incorporated PCM admixture. Retrieved data points to a complex effect of the tested plasters on possible moderation of buildings interior climate.

Preliminary Results from Powell Research Group on Integrating GRACE Satellite and Ground-based Estimates of Groundwater Storage Changes

NASA Astrophysics Data System (ADS)

Scanlon, B. R.; Zhang, Z.; Reitz, M.; Rodell, M.; Sanford, W. E.; Save, H.; Wiese, D. N.; Croteau, M. J.; McGuire, V. L.; Pool, D. R.; Faunt, C. C.; Zell, W.

2017-12-01

Groundwater storage depletion is a critical issue for many of the major aquifers in the U.S., particularly during intense droughts. GRACE (Gravity Recovery and Climate Experiment) satellite-based estimates of groundwater storage changes have attracted considerable media attention in the U.S. and globally and interest in GRACE products continues to increase. For this reason, a Powell Research Group was formed to: (1) Assess variations in groundwater storage using a variety of GRACE products and other storage components (snow, surface water, and soil moisture) for major aquifers in the U.S., (2) Quantify long-term trends in groundwater storage from ground-based monitoring and regional and national modeling, and (3) Use ground-based monitoring and modeling to interpret GRACE water storage changes within the context of extreme droughts and over-exploitation of groundwater. The group now has preliminary estimates from long-term trends and seasonal fluctuations in water storage using different GRACE solutions, including CSR, JPL and GSFC. Approaches to quantifying uncertainties in GRACE data are included. This work also shows how GRACE sees groundwater depletion in unconfined versus confined aquifers, and plans for future work will link GRACE data to regional groundwater models. The wealth of ground-based observations for the U.S. provides a unique opportunity to assess the reliability of GRACE-based estimates of groundwater storage changes.

Forest Carbon Storage in the Northern Midwest, USA: A Bottom-Up Scaling Approach Combining Local Meteorological and Biometric Data With Regional Forest Inventories

NASA Astrophysics Data System (ADS)

Curtis, P. S.; Gough, C. M.; Vogel, C. S.

2005-12-01

Carbon (C) storage increasingly is considered an important part of the economic return of forestlands, making easily parameterized models for assessing current and future C storage important for both ecosystem and money managers. For the deciduous forests of the northern midwest, USA, detailed information relating annual C storage to local site characteristics can be combined with spatially extensive forest inventories to produce simple, robust models of C storage useful at a variety of scales. At the University of Michigan Biological Station (45o35`' N, 84o42`' W) we measured C storage, or net ecosystem production (NEP), in 65 forest stands varying in age, disturbance history, and productivity (site index) using biometric methods, and independently measured net C exchange at the landscape level using meteorological methods. Our biometric and meteorological estimates of NEP converged to within 1% of each other over five years, providing important confirmation of the robustness of these two approaches applied within northern deciduous forests (Gough et al. 2005). We found a significant relationship between NEP, stand age ( A, yrs), and site index ( Is, m), where NEP = 0.134 + 0.022 * (LN[ A* Is]) (r2 = 0.50, P < 0.02). Site index is an integrated measure of site quality, expressed as 50 yr canopy height. We then used stand age and site index data from forests of similar species composition reported in the USDA Forest Inventory and Analysis database (ncrs2.fs.fed.us/4801/fiadb/) to estimate forest C storage at different scales across the upper midwest, Great Lakes region. Model estimates were validated against independent estimates of C storage for other forests in the region. At the local ecosystem-level (~1 km2) C storage averaged 1.52 Mg ha-1 yr-1. Scaling to the two-county area surrounding our meteorological and biometric study sites, average stand age decreased and site index increased, resulting in estimated storage of 1.62 Mg C ha-1 yr-1, or 0.22 Tg C yr-1 in the 1350 km2 of deciduous forest in this area. For the state of Michigan (31,537 km2 of deciduous forest), average uptake was estimated at 1.55 Mg C ha-1 yr-1, or 4.9 Tg C yr-1 total storage. For the three state region encompassing Minnesota, Michigan, and Wisconsin (97,769 km2 of deciduous forest), we estimated average storage in these forests of 1.51 Mg C ha-1 yr-1, or 14.1 Tg C yr-1 total storage. This storage represents ~ 13 % of regional anthropogenic C emissions (US Department of Energy, 2003). This modest rate of C storage by forests in the region may decrease due to changes in forest succession and land-use, and also in response to climate-driven shifts in the balance between photosynthesis and respiration. Gough C.M., Vogel C.S., Schmid H.P., Su H.-B., and Curtis P.S. 2005. Multi-year convergence of biometric and meteorological estimates of forest carbon storage. Agricultural and Forest Meteorology, In Press.

Carbon dioxide utilization in a microalga-based biorefinery: Efficiency of carbon removal and economic performance under carbon taxation.

PubMed

Wiesberg, Igor Lapenda; Brigagão, George Victor; de Medeiros, José Luiz; de Queiroz Fernandes Araújo, Ofélia

2017-12-01

Coal-fired power plants are major stationary sources of carbon dioxide and environmental constraints demand technologies for abatement. Although Carbon Capture and Storage is the most mature route, it poses severe economic penalty to power generation. Alternatively, this penalty is potentially reduced by Carbon Capture and Utilization, which converts carbon dioxide to valuable products, monetizing it. This work evaluates a route consisting of carbon dioxide bio-capture by Chlorella pyrenoidosa and use of the resulting biomass as feedstock to a microalgae-based biorefinery; Carbon Capture and Storage route is evaluated as a reference technology. The integrated arrangement comprises: (a) carbon dioxide biocapture in a photobioreactor, (b) oil extraction from part of the produced biomass, (b) gasification of remaining biomass to obtain bio-syngas, and (c) conversion of bio-syngas to methanol. Calculation of capital and operational expenditures are estimated based on mass and energy balances obtained by process simulation for both routes (Carbon Capture and Storage and the biorefinery). Capital expenditure for the biorefinery is higher by a factor of 6.7, while operational expenditure is lower by a factor of 0.45 and revenues occur only for this route, with a ratio revenue/operational expenditure of 1.6. The photobioreactor is responsible for one fifth of the biorefinery capital expenditure, with footprint of about 1000 ha, posing the most significant barrier for technical and economic feasibility of the proposed biorefinery. The Biorefinery and Carbon Capture and Storage routes show carbon dioxide capture efficiency of 73% and 48%, respectively, with capture cost of 139$/t and 304$/t. Additionally, the biorefinery has superior performance in all evaluated metrics of environmental impacts. Copyright © 2017 Elsevier Ltd. All rights reserved.

Carbon storage potential increases with increasing ratio of C4 to C3 grass cover and soil productivity in restored tallgrass prairies.

PubMed

Spiesman, Brian J; Kummel, Herika; Jackson, Randall D

2018-02-01

Long-term soil carbon (C) storage is essential for reducing CO 2 in the atmosphere. Converting unproductive and environmentally sensitive agricultural lands to grasslands for bioenergy production may enhance C storage. However, a better understanding of the interacting effects of grass functional composition (i.e., relative abundance of C 4 and C 3 grass cover) and soil productivity on C storage will help guide sustainable grassland management. Our objective was to examine the relationship between grass functional composition and potential C storage and how it varies with potential soil productivity. We estimated C inputs from above- and belowground net primary productivity (ANPP and BNPP), and heterotrophic respiration (R H ) to calculate net ecosystem production (NEP), a measure of potential soil C storage, in grassland plots of relatively high- and low-productivity soils spanning a gradient in the ratio of C 4 to C 3 grass cover (C 4 :C 3 ). NEP increased with increasing C 4 :C 3 , but only in potentially productive soils. The positive relationship likely stemmed from increased ANPP, rather than BNPP, which was possibly related to efficient resource-use and physiological/anatomical advantages of C 4 plants. R H was negatively correlated with C 4 :C 3 , possibly because of changes in microclimate or plant-microbe interactions. It is possible that in potentially productive soils, C storage can be enhanced by favoring C 4 over C 3 grasses through increased ANPP and BNPP and reduced R H . Results also suggest that potential C storage gains from C 4 productivity would not be undermined by a corresponding increase in R H .

Estimating geological CO2 storage security to deliver on climate mitigation.

PubMed

Alcalde, Juan; Flude, Stephanie; Wilkinson, Mark; Johnson, Gareth; Edlmann, Katriona; Bond, Clare E; Scott, Vivian; Gilfillan, Stuart M V; Ogaya, Xènia; Haszeldine, R Stuart

2018-06-12

Carbon capture and storage (CCS) can help nations meet their Paris CO 2 reduction commitments cost-effectively. However, lack of confidence in geologic CO 2 storage security remains a barrier to CCS implementation. Here we present a numerical program that calculates CO 2 storage security and leakage to the atmosphere over 10,000 years. This combines quantitative estimates of geological subsurface CO 2 retention, and of surface CO 2 leakage. We calculate that realistically well-regulated storage in regions with moderate well densities has a 50% probability that leakage remains below 0.0008% per year, with over 98% of the injected CO 2 retained in the subsurface over 10,000 years. An unrealistic scenario, where CO 2 storage is inadequately regulated, estimates that more than 78% will be retained over 10,000 years. Our modelling results suggest that geological storage of CO 2 can be a secure climate change mitigation option, but we note that long-term behaviour of CO 2 in the subsurface remains a key uncertainty.

Main Trend Extraction Based on Irregular Sampling Estimation and Its Application in Storage Volume of Internet Data Center

PubMed Central

Dou, Chao

2016-01-01

The storage volume of internet data center is one of the classical time series. It is very valuable to predict the storage volume of a data center for the business value. However, the storage volume series from a data center is always “dirty,” which contains the noise, missing data, and outliers, so it is necessary to extract the main trend of storage volume series for the future prediction processing. In this paper, we propose an irregular sampling estimation method to extract the main trend of the time series, in which the Kalman filter is used to remove the “dirty” data; then the cubic spline interpolation and average method are used to reconstruct the main trend. The developed method is applied in the storage volume series of internet data center. The experiment results show that the developed method can estimate the main trend of storage volume series accurately and make great contribution to predict the future volume value. 
 PMID:28090205

Main Trend Extraction Based on Irregular Sampling Estimation and Its Application in Storage Volume of Internet Data Center.

PubMed

Miao, Beibei; Dou, Chao; Jin, Xuebo

2016-01-01

The storage volume of internet data center is one of the classical time series. It is very valuable to predict the storage volume of a data center for the business value. However, the storage volume series from a data center is always "dirty," which contains the noise, missing data, and outliers, so it is necessary to extract the main trend of storage volume series for the future prediction processing. In this paper, we propose an irregular sampling estimation method to extract the main trend of the time series, in which the Kalman filter is used to remove the "dirty" data; then the cubic spline interpolation and average method are used to reconstruct the main trend. The developed method is applied in the storage volume series of internet data center. The experiment results show that the developed method can estimate the main trend of storage volume series accurately and make great contribution to predict the future volume value. 
 .

Efficient numerical simulation of heat storage in subsurface georeservoirs

NASA Astrophysics Data System (ADS)

Boockmeyer, A.; Bauer, S.

2015-12-01

The transition of the German energy market towards renewable energy sources, e.g. wind or solar power, requires energy storage technologies to compensate for their fluctuating production. Large amounts of energy could be stored in georeservoirs such as porous formations in the subsurface. One possibility here is to store heat with high temperatures of up to 90°C through borehole heat exchangers (BHEs) since more than 80 % of the total energy consumption in German households are used for heating and hot water supply. Within the ANGUS+ project potential environmental impacts of such heat storages are assessed and quantified. Numerical simulations are performed to predict storage capacities, storage cycle times, and induced effects. For simulation of these highly dynamic storage sites, detailed high-resolution models are required. We set up a model that accounts for all components of the BHE and verified it using experimental data. The model ensures accurate simulation results but also leads to large numerical meshes and thus high simulation times. In this work, we therefore present a numerical model for each type of BHE (single U, double U and coaxial) that reduces the number of elements and the simulation time significantly for use in larger scale simulations. The numerical model includes all BHE components and represents the temporal and spatial temperature distribution with an accuracy of less than 2% deviation from the fully discretized model. By changing the BHE geometry and using equivalent parameters, the simulation time is reduced by a factor of ~10 for single U-tube BHEs, ~20 for double U-tube BHEs and ~150 for coaxial BHEs. Results of a sensitivity study that quantify the effects of different design and storage formation parameters on temperature distribution and storage efficiency for heat storage using multiple BHEs are then shown. It is found that storage efficiency strongly depends on the number of BHEs composing the storage site, their distance and the cycle time. The temperature distribution is most sensitive to thermal conductivity of both borehole grouting and storage formation while storage efficiency is mainly controlled by the thermal conductivity of the storage formation.

Design of a high temperature subsurface thermal energy storage system

NASA Astrophysics Data System (ADS)

Zheng, Qi

Solar thermal energy is taking up increasing proportions of future power generation worldwide. Thermal energy storage technology is a key method for compensating for the inherent intermittency of solar resources and solving the time mismatch between solar energy supply and electricity demand. However, there is currently no cost-effective high-capacity compact storage technology available (Bakker et al., 2008). The goal of this work is to propose a high temperature subsurface thermal energy storage (HSTES) technology and demonstrate its potential energy storage capability by developing a solar-HSTES-electricity generation system. In this work, main elements of the proposed system and their related state-of-art technologies are reviewed. A conceptual model is built to illustrate the concept, design, operating procedure and application of such a system. A numerical base model is built within the TOUGH2-EOS1 multiphase flow simulator for the evaluation of system performance. Additional models are constructed and simulations are done to identify the effect of different operational and geological influential factors on the system performance. Our work shows that when the base model is run with ten years operation of alternate injection and production processes - each for a month - with a thermal power input of 10.85 MW, about 83% of the injected thermal energy could be recovered within each working cycle from a stabilized HSTES system. After the final conversion into electrical energy, a relative (compared with the direct use of hot water) electricity generation efficiency of 73% is obtained. In a typical daily storage scenario, the simulated thermal storage efficiency could exceed 78% and the relative electricity generation efficiency is over 66% in the long run. In a seasonal storage scenario, these two efficiencies reach 69% and 53% respectively by the end of the simulation period of 10 years. Additional simulations reveal a thinner storage aquifer with a higher horizontal-to-vertical permeability ratio is favored by the storage system. A basin-shape reservoir is more favored than a flat reservoir, while a flat reservoir is better than a dome-shape reservoir. The effect of aquifer stratification is variable: it depends on the relative position of the well screen and the impermeable lenses within the reservoir. From the operational aspect, the well screen position is crucial and properly shortening the screen length can help heat recovery. The proportion of the injection/storage/recovery processes within a cycle, rather than their exact lengths, affects the storage efficiency. Reservoir preheating helps improve the energy storage efficiency for the first several cycles. However, it does not contribute much to the system performance in the long run. Simulations also indicate that buoyancy effect is of significant importance in heat distribution and the plume migration. Reducing the gravity override effect of the heat plume could be an important consideration in efficiency optimization.

NETL CO 2 Storage prospeCtive Resource Estimation Excel aNalysis (CO 2-SCREEN) User's Manual

DOE Office of Scientific and Technical Information (OSTI.GOV)

Sanguinito, Sean M.; Goodman, Angela; Levine, Jonathan

This user’s manual guides the use of the National Energy Technology Laboratory’s (NETL) CO 2 Storage prospeCtive Resource Estimation Excel aNalysis (CO 2-SCREEN) tool, which was developed to aid users screening saline formations for prospective CO 2 storage resources. CO 2- SCREEN applies U.S. Department of Energy (DOE) methods and equations for estimating prospective CO 2 storage resources for saline formations. CO2-SCREEN was developed to be substantive and user-friendly. It also provides a consistent method for calculating prospective CO 2 storage resources that allows for consistent comparison of results between different research efforts, such as the Regional Carbon Sequestration Partnershipsmore » (RCSP). CO 2-SCREEN consists of an Excel spreadsheet containing geologic inputs and outputs, linked to a GoldSim Player model that calculates prospective CO 2 storage resources via Monte Carlo simulation.« less

Estimation of Transport and Kinetic Parameters of Vanadium Redox Batteries Using Static Cells

DOE Office of Scientific and Technical Information (OSTI.GOV)

Lee, Seong Beom; Pratt, III, Harry D.; Anderson, Travis M.

Mathematical models of Redox Flow Batteries (RFBs) can be used to analyze cell performance, optimize battery operation, and control the energy storage system efficiently. Among many other models, physics-based electrochemical models are capable of predicting internal states of the battery, such as temperature, state-of-charge, and state-of-health. In the models, estimating parameters is an important step that can study, analyze, and validate the models using experimental data. A common practice is to determine these parameters either through conducting experiments or based on the information available in the literature. However, it is not easy to investigate all proper parameters for the modelsmore » through this way, and there are occasions when important information, such as diffusion coefficients and rate constants of ions, has not been studied. Also, the parameters needed for modeling charge-discharge are not always available. In this paper, an efficient way to estimate parameters of physics-based redox battery models will be proposed. Furthermore, this paper also demonstrates that the proposed approach can study and analyze aspects of capacity loss/fade, kinetics, and transport phenomena of the RFB system.« less

Estimation of Transport and Kinetic Parameters of Vanadium Redox Batteries Using Static Cells

DOE PAGES

Lee, Seong Beom; Pratt, III, Harry D.; Anderson, Travis M.; ...

2018-03-27

Mathematical models of Redox Flow Batteries (RFBs) can be used to analyze cell performance, optimize battery operation, and control the energy storage system efficiently. Among many other models, physics-based electrochemical models are capable of predicting internal states of the battery, such as temperature, state-of-charge, and state-of-health. In the models, estimating parameters is an important step that can study, analyze, and validate the models using experimental data. A common practice is to determine these parameters either through conducting experiments or based on the information available in the literature. However, it is not easy to investigate all proper parameters for the modelsmore » through this way, and there are occasions when important information, such as diffusion coefficients and rate constants of ions, has not been studied. Also, the parameters needed for modeling charge-discharge are not always available. In this paper, an efficient way to estimate parameters of physics-based redox battery models will be proposed. Furthermore, this paper also demonstrates that the proposed approach can study and analyze aspects of capacity loss/fade, kinetics, and transport phenomena of the RFB system.« less

DOE Office of Scientific and Technical Information (OSTI.GOV)

Garbesi, Karina; Vossos, Vagelis; Sanstad, Alan

An increasing number of energy efficient appliances operate on direct current (DC) internally, offering the potential to use DC from renewable energy systems directly and avoiding the losses inherent in converting power to alternating current (AC) and back. This paper investigates that potential for net-metered residences with on-site photovoltaics (PV) by modeling the net power draw of the ‘direct-DC house’ with respect to today’s typical configuration, assuming identical DC-internal loads. Power draws were modeled for houses in 14 U.S. cities, using hourly, simulated PV-system output and residential loads. The latter were adjusted to reflect a 33% load reduction, representative ofmore » the most efficient DC-internal technology, based on an analysis of 32 electricity end-uses. The model tested the effect of climate, electric vehicle (EV) loads, electricity storage, and load shifting on electricity savings; a sensitivity analysis was conducted to determine how future changes in the efficiencies of power system components might affect savings potential. Based on this work, we estimate that net-metered PV residences could save 5% of their total electricity load for houses without storage and 14% for houses with storage. Based on residential PV penetration projections for year 2035 obtained from the National Energy Modeling System (2.7% for the reference case and 11.2% for the extended policy case), direct-DC could save the nation 10 trillion Btu (without storage) or 40 trillion Btu (with storage). Shifting the cooling load by two hours earlier in the day (pre-cooling) has negligible benefits for energy savings. Direct-DC provides no energy savings benefits for EV charging, to the extent that charging occurs at night. However, if charging occurred during the day, for example with employees charging while at work, the benefits would be large. Direct-DC energy savings are sensitive to power system and appliance conversion efficiencies but are not significantly influenced by climate. While direct-DC for residential applications will most likely arise as a spin-off of developments in the commercial sector—because of lower barriers to market entry and larger energy benefits resulting from the higher coincidence between load and insolation—this paper demonstrates that there are substantial benefits in the residential sector as well. Among residential applications, space cooling derives the largest energy savings from being delivered by a direct-DC system. It is the largest load for the average residence on a national basis and is particularly so in high-load regions. It is also the load with highest solar coincidence.« less

Estimation of surface water storage in the Congo Basin

NASA Astrophysics Data System (ADS)

O'Loughlin, F.; Neal, J. C.; Schumann, G.; Beighley, E.; Bates, P. D.

2015-12-01

For many large river basins, especially in Africa, the lack of access to in-situ measurements, and the large areas involved, make modelling of water storage and runoff difficult. However, remote sensing datasets are useful alternative sources of information, which overcome these issues. In this study, we focus on the Congo Basin and, in particular, the cuvette central. Despite being the second largest river basin on earth and containing a large percentage of the world's tropical wetlands and forest, little is known about this basin's hydrology. Combining discharge estimates from in-situ measurements and outputs from a hydrological model, we build the first large-scale hydrodynamic model for this region to estimate the volume of water stored in the corresponding floodplains and to investigate how important these floodplains are to the behaviour of the overall system. This hydrodynamic model covers an area over 1.6 million square kilometres and 13 thousand kilometres of rivers and is calibrated to water surface heights at 33 virtual gauging stations obtained from ESA's Envisat satellite. Our results show that the use of different sources of discharge estimations and calibration via Envisat observations can produce accurate water levels and downstream discharges. Our model produced un-biased (bias =-0.08 m), sub-metre Root Mean Square Error (RMSE =0.862 m) with a Nash-Sutcliffe efficiency greater than 80% (NSE =0.81). The spatial-temporal variations in our simulated inundated areas are consistent with the pattern obtained from satellites. Overall, we find a high correlation coefficient (R =0.88) between our modelled inundated areas and those estimated from satellites.

Carbon exchange and quantum efficiency of ecosystem carbon storage in mature deciduous and old-growth coniferous forest in central New England in 2001

NASA Astrophysics Data System (ADS)

Hadley, J. L.; Urbanski, S. P.

2002-12-01

Carbon storage in forests of the northeastern U.S. and adjacent Canada may be a significant carbon sink, as forests and soils in this region have recovered after agricultural abandonment in the 19th century. Data collected during the 1990's showed that an area of 70 to 100 year old deciduous forest on abandoned farmland in central Massachusetts stored an average of 2.0 Mg C/ha/yr in trees and soil. During 2001 we measured carbon exchange and environmental parameters (above-canopy air temperature, atmospheric humidity, photosynthetically active radiation (PAR) and soil temperature) in both the 70-100 year old deciduous forest and in a nearby eastern hemlock (Tsuga canadensis L.)-dominated forest with trees up to 220 years old that was never cleared for agricultural use. The deciduous forest stored more than 4 Mg C/ ha in 2001, far higher than in any previous year since measurements started in 1991. Highest monthly deciduous forest carbon storage (1.8 - 1.9 Mg ha-1 month-1) occurred in July and August. The hemlock forest stored about 3 Mg C/ha, with peak storage in April and May (0.8 - 0.9Mg C ha-1 month-1), and little or no C storage during August. The differences in carbon storage between the two forests were related to differences in quantum use efficiency. Quantum efficiency of ecosystem carbon storage in the foliated deciduous forest averaged about 0.16 g C /mol PAR and was insensitive to temperature after leaf maturation. In contrast, the average hemlock forest quantum efficiency declined from about 0.10 g C /mol PAR at daily average above-canopy air temperature (T{a}{v}{g}) = 5 oC to zero quantum efficiency (no net carbon storage) at T{a}{v}{g} = 23 oC. Optimum temperatures for carbon storage in the hemlock forest occurred in April. Differences between the two forests are likely due primarily to a higher maximum photosynthetic rate and a more positive temperature response of leaf-level photosynthesis in red oak (the dominant deciduous species) as compared with eastern hemlock. Maintenance of high soil respiration in the hemlock forest during warm dry summer weather may also contribute to declining quantum efficiency of carbon storage in the hemlock forest during the summer.

Evaluation strategy of regenerative braking energy for supercapacitor vehicle.

PubMed

Zou, Zhongyue; Cao, Junyi; Cao, Binggang; Chen, Wen

2015-03-01

In order to improve the efficiency of energy conversion and increase the driving range of electric vehicles, the regenerative energy captured during braking process is stored in the energy storage devices and then will be re-used. Due to the high power density of supercapacitors, they are employed to withstand high current in the short time and essentially capture more regenerative energy. The measuring methods for regenerative energy should be investigated to estimate the energy conversion efficiency and performance of electric vehicles. Based on the analysis of the regenerative braking energy system of a supercapacitor vehicle, an evaluation system for energy recovery in the braking process is established using USB portable data-acquisition devices. Experiments under various braking conditions are carried out. The results verify the higher efficiency of energy regeneration system using supercapacitors and the effectiveness of the proposed measurement method. It is also demonstrated that the maximum regenerative energy conversion efficiency can reach to 88%. Copyright © 2014 ISA. Published by Elsevier Ltd. All rights reserved.

National Assessment of Geologic Carbon Dioxide Storage Resources -- Trends and Interpretations

NASA Astrophysics Data System (ADS)

Buursink, M. L.; Blondes, M. S.; Brennan, S.; Drake, R., II; Merrill, M. D.; Roberts-Ashby, T. L.; Slucher, E. R.; Warwick, P.

2013-12-01

In 2012, the U.S. Geological Survey (USGS) completed an assessment of the technically accessible storage resource (TASR) for carbon dioxide (CO2) in geologic formations underlying the onshore and State waters area of the United States. The formations assessed are at least 3,000 feet (914 meters) below the ground surface. The TASR is an estimate of the CO2 storage resource that may be available for CO2 injection and storage that is based on present-day geologic and hydrologic knowledge of the subsurface and current engineering practices. Individual storage assessment units (SAUs) for 36 basins or study areas were defined on the basis of geologic and hydrologic characteristics outlined in the USGS assessment methodology. The mean national TASR is approximately 3,000 metric gigatons. To augment the release of the assessment, this study reviews input estimates and output results as a part of the resource calculation. Included in this study are a collection of both cross-plots and maps to demonstrate our trends and interpretations. Alongside the assessment, the input estimates were examined for consistency between SAUs and cross-plotted to verify expected trends, such as decreasing storage formation porosity with increasing SAU depth, for instance, and to show a positive correlation between storage formation porosity and permeability estimates. Following the assessment, the output results were examined for correlation with selected input estimates. For example, there exists a positive correlation between CO2 density and the TASR, and between storage formation porosity and the TASR, as expected. These correlations, in part, serve to verify our estimates for the geologic variables. The USGS assessment concluded that the Coastal Plains Region of the eastern and southeastern United States contains the largest storage resource. Within the Coastal Plains Region, the storage resources from the U.S. Gulf Coast study area represent 59 percent of the national CO2 storage capacity. As part of this follow up study, additional maps were generated to show the geographic distribution of the input estimates and the output results across the U.S. For example, the distribution of the SAUs with fresh, saline or mixed formation water quality is shown. Also mapped is the variation in CO2 density as related to basin location and to related properties such as subsurface temperature and pressure. Furthermore, variation in the estimated SAU depth and resulting TASR are shown across the assessment study areas, and these depend on the geologic basin size and filling history. Ultimately, multiple map displays are possible with the complete data set of input estimates and range of reported results. The findings from this study show the effectiveness of the USGS methodology and the robustness of the assessment.

Hydrologic considerations for estimation of storage-capacity requirements of impounding and side-channel reservoirs for water supply in Ohio

USGS Publications Warehouse

Koltun, G.F.

2001-01-01

This report provides data and methods to aid in the hydrologic design or evaluation of impounding reservoirs and side-channel reservoirs used for water supply in Ohio. Data from 117 streamflow-gaging stations throughout Ohio were analyzed by means of nonsequential-mass-curve-analysis techniques to develop relations between storage requirements, water demand, duration, and frequency. Information also is provided on minimum runoff for selected durations and frequencies. Systematic record lengths for the streamflow-gaging stations ranged from about 10 to 75 years; however, in many cases, additional streamflow record was synthesized. For impounding reservoirs, families of curves are provided to facilitate the estimation of storage requirements as a function of demand and the ratio of the 7-day, 2-year low flow to the mean annual flow. Information is provided with which to evaluate separately the effects of evaporation on storage requirements. Comparisons of storage requirements for impounding reservoirs determined by nonsequential-mass-curve-analysis techniques with storage requirements determined by annual-mass-curve techniques that employ probability routing to account for carryover-storage requirements indicate that large differences in computed required storages can result from the two methods, particularly for conditions where demand cannot be met from within-year storage. For side-channel reservoirs, tables of demand-storage-frequency information are provided for a primary pump relation consisting of one variable-speed pump with a pumping capacity that ranges from 0.1 to 20 times demand. Tables of adjustment ratios are provided to facilitate determination of storage requirements for 19 other pump sets consisting of assorted combinations of fixed-speed pumps or variable-speed pumps with aggregate pumping capacities smaller than or equal to the primary pump relation. The effects of evaporation on side-channel reservoir storage requirements are incorporated into the storage-requirement estimates. The effects of an instream-flow requirement equal to the 80-percent-duration flow are also incorporated into the storage-requirement estimates.

System and method for controlling an engine based on ammonia storage in multiple selective catalytic reduction catalysts

DOEpatents

Sun, MIn; Perry, Kevin L.

2015-11-20

A system according to the principles of the present disclosure includes a storage estimation module and an air/fuel ratio control module. The storage estimation module estimates a first amount of ammonia stored in a first selective catalytic reduction (SCR) catalyst and estimates a second amount of ammonia stored in a second SCR catalyst. The air/fuel ratio control module controls an air/fuel ratio of an engine based on the first amount, the second amount, and a temperature of a substrate disposed in the second SCR catalyst.

Metallic phase change material thermal storage for Dish Stirling

DOE PAGES

Andraka, C. E.; Kruizenga, A. M.; Hernandez-Sanchez, B. A.; ...

2015-06-05

Dish-Stirling systems provide high-efficiency solar-only electrical generation and currently hold the world record at 31.25%. This high efficiency results in a system with a high possibility of meeting the DOE SunShot goal of $0.06/kWh. However, current dish-Stirling systems do not incorporate thermal storage. For the next generation of non-intermittent and cost-competitive solar power plants, we propose adding a thermal energy storage system that combines latent (phase-change) energy transport and latent energy storage in order to match the isothermal input requirements of Stirling engines while also maximizing the exergetic efficiency of the entire system. This paper reports current findings in themore » area of selection, synthesis and evaluation of a suitable high performance metallic phase change material (PCM) as well as potential interactions with containment alloy materials. The metallic PCM's, while more expensive than salts, have been identified as having substantial performance advantages primarily due to high thermal conductivity, leading to high exergetic efficiency. Systems modeling has indicated, based on high dish Stirling system performance, an allowable cost of the PCM storage system that is substantially higher than SunShot goals for storage cost on tower systems. Several PCM's are identified with suitable melting temperature, cost, and performance.« less

Sedimentation survey of Lago de Matrullas, Puerto Rico, December 2001

USGS Publications Warehouse

Soler-López, Luis R.

2003-01-01

Lago de Matrullas reservoir, constructed in 1934, is located at an altitude of approximately 730 meters above mean sea level in the municipality of Orocovis in central Puerto Rico, and has a drainage area of 11.45 square kilometers. The reservoir is part of the Puerto Rico Electric Power Authority Toro Negro Hydroelectric Project, which also includes the Lago El Guineo reservoir and a hydroelectric plant to the south of the insular hydrographic divide. Historically, the drainage area had been protected from soil erosion by dense vegetation and the lack of basin development. However, transportation, potable water, and electric power infrastructure construction has facilitated development in rural areas resulting in the clearing of land. This trend in land-use changes is impacting the useful life of Lago de Matrullas. The reservoir storage capacity has been reduced from 3.71 million cubic meters in 1934 to 3.08 million cubic meters in 2001. This represents a total storage-capacity loss of 0.63 million cubic meters by 2001 (17 percent), or a long-term annual storage loss of 0.25 percent per year. The sediment trapping efficiency of Lago de Matrullas has been estimated at approximately 90 percent. If the current long-term sedimentation rate continues, Lago de Matrullas would fill by the year 2328. However, this life expectancy could be reduced at a faster than predicted rate as a result of rural development in the Lago de Matrullas basin and the high sediment trapping efficiency of the reservoir.

Performance characteristics of solar-photovoltaic flywheel-storage systems

NASA Astrophysics Data System (ADS)

Jarvinen, P. O.; Brench, B. L.; Rasmussen, N. E.

A solar photovoltaic energy flywheel storage and conversion system for residential applications was tested. Performance and efficiency measurements were conducted on the system, which utilizes low loss magnetic bearings, maximum power point tracking of the photovoltaic array, integrated permanent magnet motor generator, and output power conditioning sections of either the stand alone cycloconverter or utility interactive inverter type. The overall in/out electrical storage efficiency of the flywheel system was measured along with the power transfer efficiencies of the individual components and the system spin down tare losses. The system compares favorably with systems which use batteries and inverters.

A data driven model for the impact of IFT and density variations on CO2 sequestration in porous media

NASA Astrophysics Data System (ADS)

Nomeli, Mohammad; Riaz, Amir

2017-11-01

CO2 storage in geological formations is one of the most promising solutions for mitigating the amount of greenhouse gases released into the atmosphere. One of the important issues for CO2 storage in subsurface environments is the sealing efficiency of low-permeable cap-rocks overlying potential CO2 storage reservoirs. A novel model is proposed to find the IFT of the systems (CO2/brine-salt) in a range of temperatures (300-373 K), pressures (50-250 bar), and up to 6 molal salinity applicable to CO2 storage in geological formations through a machine learning-assisted modeling of experimental data. The IFT between mineral surfaces and CO2/brine-salt solutions determines the efficiency of enhanced oil or gas recovery operations as well as our ability to inject and store CO2 in geological formations. Finally, we use the new model to evaluate the effects of formation depth on the actual efficiency of CO2 storage. The results indicate that, in the case of CO2 storage in deep subsurface environments as a global-warming mitigation strategy, CO2 storage capacity are improved with reservoir depth.

Soil carbon storage estimation in a forested watershed using quantitative soil-landscape modeling

Treesearch

James A. Thompson; Randall K. Kolka

2005-01-01

Carbon storage in soils is important to forest ecosystems. Moreover, forest soils may serve as important C sinks for ameliorating excess atmospheric CO2. Spatial estimates of soil organic C (SOC) storage have traditionally relied upon soil survey maps and laboratory characterization data. This approach does not account for inherent variability...

Effects of storage conditions of Moringa oleifera seeds on its performance in coagulation.

PubMed

Katayon, S; Noor, M J Megat Mohd; Asma, M; Ghani, L A Abdul; Thamer, A M; Azni, I; Ahmad, J; Khor, B C; Suleyman, A M

2006-09-01

Moringa oleifera is a plant whose seeds have coagulation properties for treating water and wastewater. In this study the coagulation efficiency of Moringa oleifera kept in different storage conditions were studied. The Moringa oleifera seeds were stored at different conditions and durations; open container and closed container at room temperature (28 degrees C) and refrigerator (3 degrees C) for durations of 1, 3 and 5 months. Comparison between turbidity removal efficiency of Moringa oleifera kept in refrigerator and room temperature revealed that there was no significant difference between them. The Moringa oleifera kept in refrigerator and room temperature for one month showed higher turbidity removal efficiency, compared to those kept for 3 and 5 months, at both containers. The coagulation efficiency of Moringa oleifera was found to be dependent on initial turbidity of water samples. Highest turbidity removals were obtained for water with very high initial turbidity. In summary coagulation efficiency of Moringa oleifera was found independent of storage temperature and container, however coagulation efficiency of Moringa oleifera decreased as storage duration increased. In addition, Moringa oleifera can be used as a potential coagulant especially for very high turbidity water.

Study on storage efficiency of the fresh food e-commerce

NASA Astrophysics Data System (ADS)

Wang, Xin; Sun, Jie; Li, Huihui

2017-06-01

As the last cake in the area of e-commerce industry, the temperature of fresh food e-commerce is always rising starting from about 2014. This paper is based on the imperfection that the existing study about fresh food e-commerce is lack of studies on storage efficiency. And we took some variables in this paper such as consumers’ satisfaction and length for preservation and storage time. On this basis we built the model of storage efficiency of fresh food e-commerce. We find that as the development of fresh food e-commerce, the fresh food e-commerce enterprise will pay more attention to the consumers’ satisfaction. They can take some effective ways like reducing the wastage of fresh food and lengthening the refreshing time of fresh food and so on.

Analysis of CO2 trapping capacities and long-term migration for geological formations in the Norwegian North Sea using MRST-co2lab

NASA Astrophysics Data System (ADS)

Møll Nilsen, Halvor; Lie, Knut-Andreas; Andersen, Odd

2015-06-01

MRST-co2lab is a collection of open-source computational tools for modeling large-scale and long-time migration of CO2 in conductive aquifers, combining ideas from basin modeling, computational geometry, hydrology, and reservoir simulation. Herein, we employ the methods of MRST-co2lab to study long-term CO2 storage on the scale of hundreds of megatonnes. We consider public data sets of two aquifers from the Norwegian North Sea and use geometrical methods for identifying structural traps, percolation-type methods for identifying potential spill paths, and vertical-equilibrium methods for efficient simulation of structural, residual, and solubility trapping in a thousand-year perspective. In particular, we investigate how data resolution affects estimates of storage capacity and discuss workflows for identifying good injection sites and optimizing injection strategies.

National Assessment of Energy Storage for Grid Balancing and Arbitrage: Phase 1, WECC

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kintner-Meyer, Michael CW; Balducci, Patrick J.; Colella, Whitney G.

2012-06-01

To examine the role that energy storage could play in mitigating the impacts of the stochastic variability of wind generation on regional grid operation, the Pacific Northwest National Laboratory (PNNL) examined a hypothetical 2020 grid scenario in which additional wind generation capacity is built to meet renewable portfolio standard targets in the Western Interconnection. PNNL developed a stochastic model for estimating the balancing requirements using historical wind statistics and forecasting error, a detailed engineering model to analyze the dispatch of energy storage and fast-ramping generation devices for estimating size requirements of energy storage and generation systems for meeting new balancingmore » requirements, and financial models for estimating the life-cycle cost of storage and generation systems in addressing the future balancing requirements for sub-regions in the Western Interconnection. Evaluated technologies include combustion turbines, sodium sulfur (Na-S) batteries, lithium ion batteries, pumped-hydro energy storage, compressed air energy storage, flywheels, redox flow batteries, and demand response. Distinct power and energy capacity requirements were estimated for each technology option, and battery size was optimized to minimize costs. Modeling results indicate that in a future power grid with high-penetration of renewables, the most cost competitive technologies for meeting balancing requirements include Na-S batteries and flywheels.« less

PIMS: Memristor-Based Processing-in-Memory-and-Storage.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Cook, Jeanine

Continued progress in computing has augmented the quest for higher performance with a new quest for higher energy efficiency. This has led to the re-emergence of Processing-In-Memory (PIM) ar- chitectures that offer higher density and performance with some boost in energy efficiency. Past PIM work either integrated a standard CPU with a conventional DRAM to improve the CPU- memory link, or used a bit-level processor with Single Instruction Multiple Data (SIMD) control, but neither matched the energy consumption of the memory to the computation. We originally proposed to develop a new architecture derived from PIM that more effectively addressed energymore » efficiency for high performance scientific, data analytics, and neuromorphic applications. We also originally planned to implement a von Neumann architecture with arithmetic/logic units (ALUs) that matched the power consumption of an advanced storage array to maximize energy efficiency. Implementing this architecture in storage was our original idea, since by augmenting storage (in- stead of memory), the system could address both in-memory computation and applications that accessed larger data sets directly from storage, hence Processing-in-Memory-and-Storage (PIMS). However, as our research matured, we discovered several things that changed our original direc- tion, the most important being that a PIM that implements a standard von Neumann-type archi- tecture results in significant energy efficiency improvement, but only about a O(10) performance improvement. In addition to this, the emergence of new memory technologies moved us to propos- ing a non-von Neumann architecture, called Superstrider, implemented not in storage, but in a new DRAM technology called High Bandwidth Memory (HBM). HBM is a stacked DRAM tech- nology that includes a logic layer where an architecture such as Superstrider could potentially be implemented.« less

Organic Carbon Storage in China's Urban Areas

PubMed Central

Zhao, Shuqing; Zhu, Chao; Zhou, Decheng; Huang, Dian; Werner, Jeremy

2013-01-01

China has been experiencing rapid urbanization in parallel with its economic boom over the past three decades. To date, the organic carbon storage in China's urban areas has not been quantified. Here, using data compiled from literature review and statistical yearbooks, we estimated that total carbon storage in China's urban areas was 577±60 Tg C (1 Tg  = 1012 g) in 2006. Soil was the largest contributor to total carbon storage (56%), followed by buildings (36%), and vegetation (7%), while carbon storage in humans was relatively small (1%). The carbon density in China's urban areas was 17.1±1.8 kg C m−2, about two times the national average of all lands. The most sensitive variable in estimating urban carbon storage was urban area. Examining urban carbon storages over a wide range of spatial extents in China and in the United States, we found a strong linear relationship between total urban carbon storage and total urban area, with a specific urban carbon storage of 16 Tg C for every 1,000 km2 urban area. This value might be useful for estimating urban carbon storage at regional to global scales. Our results also showed that the fraction of carbon storage in urban green spaces was still much lower in China relative to western countries, suggesting a great potential to mitigate climate change through urban greening and green spaces management in China. PMID:23991014

Some Aspects of PDC Electrolysis

NASA Astrophysics Data System (ADS)

Poláčik, Ján; Pospíšil, Jiří

2016-10-01

In this paper, aspects of pulsed direct current (PDC) water splitting are described. Electrolysis is a simple and well-known method to produce hydrogen. The efficiency is relatively low in normal conditions using conventional DC. PDC in electrolysis brings about many advantages. It increases efficiency of hydrogen production, and performance of the electrolyser may be smoothly controlled without compromising efficiency of the process. In our approach, ultra-short pulses are applied. This method enhances efficiency of electrical energy in the process of decomposition of water into hydrogen and oxygen. Efficiency depends on frequency, shape and width of the electrical pulses. Experiments proved that efficiency was increased by 2 to 8 per cent. One of the prospects of PDC electrolysis producing hydrogen is in increase of efficiency of energy storage efficiency in the hydrogen. There are strong efforts to make the electrical grid more efficient and balanced in terms of production by installing electricity storage units. Using hydrogen as a fuel decreases air pollution and amount of carbon dioxide emissions in the air. In addition to energy storage, hydrogen is also important in transportation and chemical industry.

Simulation of groundwater flow, effects of artificial recharge, and storage volume changes in the Equus Beds aquifer near the city of Wichita, Kansas well field, 1935–2008

USGS Publications Warehouse

Kelly, Brian P.; Pickett, Linda L.; Hansen, Cristi V.; Ziegler, Andrew C.

2013-01-01

The Equus Beds aquifer is a primary water-supply source for Wichita, Kansas and the surrounding area because of shallow depth to water, large saturated thickness, and generally good water quality. Substantial water-level declines in the Equus Beds aquifer have resulted from pumping groundwater for agricultural and municipal needs, as well as periodic drought conditions. In March 2006, the city of Wichita began construction of the Equus Beds Aquifer Storage and Recovery project to store and later recover groundwater, and to form a hydraulic barrier to the known chloride-brine plume near Burrton, Kansas. In October 2009, the U.S. Geological Survey, in cooperation with the city of Wichita, began a study to determine groundwater flow in the area of the Wichita well field, and chloride transport from the Arkansas River and Burrton oilfield to the Wichita well field. Groundwater flow was simulated for the Equus Beds aquifer using the three-dimensional finite-difference groundwater-flow model MODFLOW-2000. The model simulates steady-state and transient conditions. The groundwater-flow model was calibrated by adjusting model input data and model geometry until model results matched field observations within an acceptable level of accuracy. The root mean square (RMS) error for water-level observations for the steady-state calibration simulation is 9.82 feet. The ratio of the RMS error to the total head loss in the model area is 0.049 and the mean error for water-level observations is 3.86 feet. The difference between flow into the model and flow out of the model across all model boundaries is -0.08 percent of total flow for the steady-state calibration. The RMS error for water-level observations for the transient calibration simulation is 2.48 feet, the ratio of the RMS error to the total head loss in the model area is 0.0124, and the mean error for water-level observations is 0.03 feet. The RMS error calculated for observed and simulated base flow gains or losses for the Arkansas River for the transient simulation is 7,916,564 cubic feet per day (91.6 cubic feet per second) and the RMS error divided by (/) the total range in streamflow (7,916,564/37,461,669 cubic feet per day) is 22 percent. The RMS error calculated for observed and simulated streamflow gains or losses for the Little Arkansas River for the transient simulation is 5,610,089 cubic feet per day(64.9 cubic feet per second) and the RMS error divided by the total range in streamflow (5,612,918/41,791,091 cubic feet per day) is 13 percent. The mean error between observed and simulated base flow gains or losses was 29,999 cubic feet per day (0.34 cubic feet per second) for the Arkansas River and -1,369,250 cubic feet per day (-15.8 cubic feet per second) for the Little Arkansas River. Cumulative streamflow gain and loss observations are similar to the cumulative simulated equivalents. Average percent mass balance difference for individual stress periods ranged from -0.46 to 0.51 percent. The cumulative mass balance for the transient calibration was 0.01 percent. Composite scaled sensitivities indicate the simulations are most sensitive to parameters with a large areal distribution. For the steady-state calibration, these parameters include recharge, hydraulic conductivity, and vertical conductance. For the transient simulation, these parameters include evapotranspiration, recharge, and hydraulic conductivity. The ability of the calibrated model to account for the additional groundwater recharged to the Equus Beds aquifer as part of the Aquifer Storage and Recovery project was assessed by using the U.S. Geological Survey subregional water budget program ZONEBUDGET and comparing those results to metered recharge for 2007 and 2008 and previous estimates of artificial recharge. The change in storage between simulations is the volume of water that estimates the recharge credit for the aquifer storage and recovery system. The estimated increase in storage of 1,607 acre-ft in the basin storage area compared to metered recharge of 1,796 acre-ft indicates some loss of metered recharge. Increased storage outside of the basin storage area of 183 acre-ft accounts for all but 6 acre-ft or 0.33 percent of the total. Previously estimated recharge credits for 2007 and 2008 are 1,018 and 600 acre-ft, respectively, and a total estimated recharge credit of 1,618 acre-ft. Storage changes calculated for this study are 4.42 percent less for 2007 and 5.67 percent more for 2008 than previous estimates. Total storage change for 2007 and 2008 is 0.68 percent less than previous estimates. The small difference between the increase in storage from artificial recharge estimated with the groundwater-flow model and metered recharge indicates the groundwater model correctly accounts for the additional water recharged to the Equus Beds aquifer as part of the Aquifer Storage and Recovery project. Small percent differences between inflows and outflows for all stress periods and all index cells in the basin storage area, improved calibration compared to the previous model, and a reasonable match between simulated and measured long-term base flow indicates the groundwater model accurately simulates groundwater flow in the study area. The change in groundwater level through recent years compared to the August 1940 groundwater level map has been documented and used to assess the change of storage volume of the Equus Beds aquifer in and near the Wichita well field for three different areas. Two methods were used to estimate changes in storage from simulation results using simulated change in groundwater levels in layer 1 between stress periods, and using ZONEBUDGET to calculate the change in storage in the same way the effects of artificial recharge were estimated within the basin storage area. The three methods indicate similar trends although the magnitude of storage changes differ. Information about the change in storage in response to hydrologic stresses is important for managing groundwater resources in the study area. The comparison between the three methods indicates similar storage change trends are estimated and each could be used to determine relative increases or decreases in storage. Use of groundwater level changes that do not include storage changes that occur in confined or semi-confined parts of the aquifer will slightly underestimate storage changes; however, use of specific yield and groundwater level changes to estimate storage change in confined or semi-confined parts of the aquifer will overestimate storage changes. Using only changes in shallow groundwater levels would provide more accurate storage change estimates for the measured groundwater levels method. The value used for specific yield is also an important consideration when estimating storage. For the Equus Beds aquifer the reported specific yield ranges between 0.08 and 0.35 and the storage coefficient (for confined conditions) ranges between 0.0004 and 0.16. Considering the importance of the value of specific yield and storage coefficient to estimates of storage change over time, and the wide range and substantial overlap for the reported values for specific yield and storage coefficient in the study area, further information on the distribution of specific yield and storage coefficient within the Equus Beds aquifer in the study area would greatly enhance the accuracy of estimated storage changes using both simulated groundwater level, simulated groundwater budget, or measured groundwater level methods.

Estimating the permanent loss of groundwater storage in the southern San Joaquin Valley, California

NASA Astrophysics Data System (ADS)

Smith, R. G.; Knight, R.; Chen, J.; Reeves, J. A.; Zebker, H. A.; Farr, T.; Liu, Z.

2017-03-01

In the San Joaquin Valley, California, recent droughts starting in 2007 have increased the pumping of groundwater, leading to widespread subsidence. In the southern portion of the San Joaquin Valley, vertical subsidence as high as 85 cm has been observed between June 2007 and December 2010 using Interferometric Synthetic Aperture Radar (InSAR). This study seeks to map regions where inelastic (not recoverable) deformation occurred during the study period, resulting in permanent compaction and loss of groundwater storage. We estimated the amount of permanent compaction by incorporating multiple data sets: the total deformation derived from InSAR, estimated skeletal-specific storage and hydraulic parameters, geologic information, and measured water levels during our study period. We used two approaches, one that we consider to provide an estimate of the lowest possible amount of inelastic deformation, and one that provides a more reasonable estimate. These two approaches resulted in a spatial distribution of values for the percentage of the total deformation that was inelastic, with the former estimating a spatially averaged value of 54%, and the latter a spatially averaged value of 98%. The former corresponds to the permanent loss of 4.14 × 108 m3 of groundwater storage, or roughly 5% of the volume of groundwater used over the study time period; the latter corresponds to the loss of 7.48 × 108 m3 of groundwater storage, or roughly 9% of the volume of groundwater used. This study demonstrates that a data-driven approach can be used effectively to estimate the permanent loss of groundwater storage.

Quantum storage of a photonic polarization qubit in a solid.

PubMed

Gündoğan, Mustafa; Ledingham, Patrick M; Almasi, Attaallah; Cristiani, Matteo; de Riedmatten, Hugues

2012-05-11

We report on the quantum storage and retrieval of photonic polarization quantum bits onto and out of a solid state storage device. The qubits are implemented with weak coherent states at the single photon level, and are stored for a predetermined time of 500 ns in a praseodymium doped crystal with a storage and retrieval efficiency of 10%, using the atomic frequency comb scheme. We characterize the storage by using quantum state tomography, and find that the average conditional fidelity of the retrieved qubits exceeds 95% for a mean photon number μ=0.4. This is significantly higher than a classical benchmark, taking into account the poissonian statistics and finite memory efficiency, which proves that our crystal functions as a quantum storage device for polarization qubits. These results extend the storage capabilities of solid state quantum light matter interfaces to polarization encoding, which is widely used in quantum information science.

Functionalization of graphene for efficient energy conversion and storage.

PubMed

Dai, Liming

2013-01-15

As global energy consumption accelerates at an alarming rate, the development of clean and renewable energy conversion and storage systems has become more important than ever. Although the efficiency of energy conversion and storage devices depends on a variety of factors, their overall performance strongly relies on the structure and properties of the component materials. Nanotechnology has opened up new frontiers in materials science and engineering to meet this challenge by creating new materials, particularly carbon nanomaterials, for efficient energy conversion and storage. As a building block for carbon materials of all other dimensionalities (such as 0D buckyball, 1D nanotube, 3D graphite), the two-dimensional (2D) single atomic carbon sheet of graphene has emerged as an attractive candidate for energy applications due to its unique structure and properties. Like other materials, however, a graphene-based material that possesses desirable bulk properties rarely features the surface characteristics required for certain specific applications. Therefore, surface functionalization is essential, and researchers have devised various covalent and noncovalent chemistries for making graphene materials with the bulk and surface properties needed for efficient energy conversion and storage. In this Account, I summarize some of our new ideas and strategies for the controlled functionalization of graphene for the development of efficient energy conversion and storage devices, such as solar cells, fuel cells, supercapacitors, and batteries. The dangling bonds at the edge of graphene can be used for the covalent attachment of various chemical moieties while the graphene basal plane can be modified via either covalent or noncovalent functionalization. The asymmetric functionalization of the two opposite surfaces of individual graphene sheets with different moieties can lead to the self-assembly of graphene sheets into hierarchically structured materials. Judicious application of these site-selective reactions to graphene sheets has opened up a rich field of graphene-based energy materials with enhanced performance in energy conversion and storage. These results reveal the versatility of surface functionalization for making sophisticated graphene materials for energy applications. Even though many covalent and noncovalent functionalization methods have already been reported, vast opportunities remain for developing novel graphene materials for highly efficient energy conversion and storage systems.

Damsel: A Data Model Storage Library for Exascale Science

DOE Office of Scientific and Technical Information (OSTI.GOV)

Koziol, Quincey

The goal of this project is to enable exascale computational science applications to interact conveniently and efficiently with storage through abstractions that match their data models. We will accomplish this through three major activities: (1) identifying major data model motifs in computational science applications and developing representative benchmarks; (2) developing a data model storage library, called Damsel, that supports these motifs, provides efficient storage data layouts, incorporates optimizations to enable exascale operation, and is tolerant to failures; and (3) productizing Damsel and working with computational scientists to encourage adoption of this library by the scientific community.

Storage and computationally efficient permutations of factorized covariance and square-root information matrices

NASA Technical Reports Server (NTRS)

Muellerschoen, R. J.

1988-01-01

A unified method to permute vector-stored upper-triangular diagonal factorized covariance (UD) and vector stored upper-triangular square-root information filter (SRIF) arrays is presented. The method involves cyclical permutation of the rows and columns of the arrays and retriangularization with appropriate square-root-free fast Givens rotations or elementary slow Givens reflections. A minimal amount of computation is performed and only one scratch vector of size N is required, where N is the column dimension of the arrays. To make the method efficient for large SRIF arrays on a virtual memory machine, three additional scratch vectors each of size N are used to avoid expensive paging faults. The method discussed is compared with the methods and routines of Bierman's Estimation Subroutine Library (ESL).

Precipitation Storage Efficiency During Fallow in Wheat-Fallow Systems

USDA-ARS?s Scientific Manuscript database

Wheat-fallow production systems arose in order to stabilize widely ranging wheat yields that resulted from highly variable precipitation in the Great Plains. Historically, precipitation storage efficiency (PSE) over the fallow period increased over time as inversion tillage systems used for weed con...

Innovative applications of energy storage in a restructured electricity marketplace : Phase III final report : a study for the DOE Energy Storage Systems Program.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Eyer, James M.; Erdman, Bill; Iannucci, Joseph J., Jr.

2005-03-01

This report describes Phase III of a project entitled Innovative Applications of Energy Storage in a Restructured Electricity Marketplace. For this study, the authors assumed that it is feasible to operate an energy storage plant simultaneously for two primary applications: (1) energy arbitrage, i.e., buy-low-sell-high, and (2) to reduce peak loads in utility ''hot spots'' such that the utility can defer their need to upgrade transmission and distribution (T&D) equipment. The benefits from the arbitrage plus T&D deferral applications were estimated for five cases based on the specific requirements of two large utilities operating in the Eastern U.S. A numbermore » of parameters were estimated for the storage plant ratings required to serve the combined application: power output (capacity) and energy discharge duration (energy storage). In addition to estimating the various financial expenditures and the value of electricity that could be realized in the marketplace, technical characteristics required for grid-connected distributed energy storage used for capacity deferral were also explored.« less

Modeling of Single and Dual Reservoir Porous Media Compressed Gas (Air and CO2) Storage Systems

NASA Astrophysics Data System (ADS)

Oldenburg, C. M.; Liu, H.; Borgia, A.; Pan, L.

2017-12-01

Intermittent renewable energy sources are causing increasing demand for energy storage. The deep subsurface offers promising opportunities for energy storage because it can safely contain high-pressure gases. Porous media compressed air energy storage (PM-CAES) is one approach, although the only facilities in operation are in caverns (C-CAES) rather than porous media. Just like in C-CAES, PM-CAES operates generally by injecting working gas (air) through well(s) into the reservoir compressing the cushion gas (existing air in the reservoir). During energy recovery, high-pressure air from the reservoir is mixed with fuel in a combustion turbine to produce electricity, thereby reducing compression costs. Unlike in C-CAES, the storage of energy in PM-CAES occurs variably across pressure gradients in the formation, while the solid grains of the matrix can release/store heat. Because air is the working gas, PM-CAES has fairly low thermal efficiency and low energy storage density. To improve the energy storage density, we have conceived and modeled a closed-loop two-reservoir compressed CO2 energy storage system. One reservoir is the low-pressure reservoir, and the other is the high-pressure reservoir. CO2 is cycled back and forth between reservoirs depending on whether energy needs to be stored or recovered. We have carried out thermodynamic and parametric analyses of the performance of an idealized two-reservoir CO2 energy storage system under supercritical and transcritical conditions for CO2 using a steady-state model. Results show that the transcritical compressed CO2 energy storage system has higher round-trip efficiency and exergy efficiency, and larger energy storage density than the supercritical compressed CO2 energy storage. However, the configuration of supercritical compressed CO2 energy storage is simpler, and the energy storage densities of the two systems are both higher than that of PM-CAES, which is advantageous in terms of storage volume for a given power rating.

Efficiency of different storage media for avulsed teeth in animal models: a systematic review.

PubMed

Longo, Daniele L; Fumes, Ana C; Küchler, Erika C; Paula-Silva, Francisco W G; Nelson-Filho, Paulo; Silva, Léa A B

2018-02-01

Tooth avulsion consists of the complete displacement of a tooth from the alveolar socket. When immediate replantation is not possible, the avulsed tooth should be kept in a storage medium capable of maintaining the viability of periodontal ligament (PDL) cells on the root surface. However, there is no consensus on the best storage medium able to prevent sequels such as ankylosis and tooth resorption. The aim of this study was to perform a systematic review to evaluate the in vivo effectiveness of different storage media for avulsed teeth. Two reviewers performed a database search for studies published between January 1950 and December 2015 which were indexed in the PubMed, Scopus, Web of Science, and Bireme databases. An additional manual search was performed. Studies with animal models that evaluated tooth avulsion, storage media, and replantation were included. After full-text analysis of the potentially relevant studies, the selected studies were included in the systematic review. The database search found 157 distinct studies evaluating avulsed teeth storage media. However, only six studies met the selection criteria and were included in the review. There was a high variability in the study estimates for the parameters analyzed. When assessing the quality and level of evidence of each study, one study was rated as having a very low level of evidence, four studies had low levels of evidence, and one had a moderate level of evidence. As a result of data heterogeneity and limitations of the studies, there was insufficient evidence to determine the most effective storage medium for avulsed teeth. © 2017 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

Rock bed thermal storage: Concepts and costs

NASA Astrophysics Data System (ADS)

Allen, Kenneth; von Backström, Theodor; Joubert, Eugene; Gauché, Paul

2016-05-01

Thermal storage enables concentrating solar power (CSP) plants to provide baseload or dispatchable power. Currently CSP plants use two-tank molten salt thermal storage, with estimated capital costs of about 22-30 /kWhth. In the interests of reducing CSP costs, alternative storage concepts have been proposed. In particular, packed rock beds with air as the heat transfer fluid offer the potential of lower cost storage because of the low cost and abundance of rock. Two rock bed storage concepts which have been formulated for use at temperatures up to at least 600 °C are presented and a brief analysis and cost estimate is given. The cost estimate shows that both concepts are capable of capital costs less than 15 /kWhth at scales larger than 1000 MWhth. Depending on the design and the costs of scaling containment, capital costs as low as 5-8 /kWhth may be possible. These costs are between a half and a third of current molten salt costs.

Application of multiple-point geostatistics to simulate the effect of small-scale aquifer heterogeneity on the efficiency of aquifer thermal energy storage

NASA Astrophysics Data System (ADS)

Possemiers, Mathias; Huysmans, Marijke; Batelaan, Okke

2015-08-01

Adequate aquifer characterization and simulation using heat transport models are indispensible for determining the optimal design for aquifer thermal energy storage (ATES) systems and wells. Recent model studies indicate that meter-scale heterogeneities in the hydraulic conductivity field introduce a considerable uncertainty in the distribution of thermal energy around an ATES system and can lead to a reduction in the thermal recoverability. In a study site in Bierbeek, Belgium, the influence of centimeter-scale clay drapes on the efficiency of a doublet ATES system and the distribution of the thermal energy around the ATES wells are quantified. Multiple-point geostatistical simulation of edge properties is used to incorporate the clay drapes in the models. The results show that clay drapes have an influence both on the distribution of thermal energy in the subsurface and on the efficiency of the ATES system. The distribution of the thermal energy is determined by the strike of the clay drapes, with the major axis of anisotropy parallel to the clay drape strike. The clay drapes have a negative impact (3.3-3.6 %) on the energy output in the models without a hydraulic gradient. In the models with a hydraulic gradient, however, the presence of clay drapes has a positive influence (1.6-10.2 %) on the energy output of the ATES system. It is concluded that it is important to incorporate small-scale heterogeneities in heat transport models to get a better estimate on ATES efficiency and distribution of thermal energy.

Application of multiple-point geostatistics to simulate the effect of small scale aquifer heterogeneity on the efficiency of Aquifer Thermal Energy Storage (ATES)

NASA Astrophysics Data System (ADS)

Possemiers, Mathias; Huysmans, Marijke; Batelaan, Okke

2015-04-01

Adequate aquifer characterization and simulation using heat transport models are indispensible for determining the optimal design for Aquifer Thermal Energy Storage (ATES) systems and wells. Recent model studies indicate that meter scale heterogeneities in the hydraulic conductivity field introduce a considerable uncertainty in the distribution of thermal energy around an ATES system and can lead to a reduction in the thermal recoverability. In this paper, the influence of centimeter scale clay drapes on the efficiency of a doublet ATES system and the distribution of the thermal energy around the ATES wells are quantified. Multiple-point geostatistical simulation of edge properties is used to incorporate the clay drapes in the models. The results show that clay drapes have an influence both on the distribution of thermal energy in the subsurface and on the efficiency of the ATES system. The distribution of the thermal energy is determined by the strike of the clay drapes, with the major axis of anisotropy parallel to the clay drape strike. The clay drapes have a negative impact (3.3 - 3.6%) on the energy output in the models without a hydraulic gradient. In the models with a hydraulic gradient, however, the presence of clay drapes has a positive influence (1.6 - 10.2%) on the energy output of the ATES system. It is concluded that it is important to incorporate small scale heterogeneities in heat transport models to get a better estimate on ATES efficiency and distribution of thermal energy.

Larvicidal efficiency of the mushroom Amanitamuscaria (Agaricales, Amanitaceae) against the mosquito Culexquinquefasciatus (Diptera, Culicidae).

PubMed

Cárcamo, Marcial Corrêa; Carapeto, Luiz Paiva; Duarte, Jucelio Peter; Bernardi, Eduardo; Ribeiro, Paulo Bretanha

2016-02-01

We report the larvicidal activity of two formulations from Amanita muscariaagainst Culex quinquefasciatus, as well as the viability of the aqueous extract after storage. METHODS The larvicidal activity of aqueous extract and powder from A. muscaria, and the viability of the aqueous extract after storage, were evaluated. RESULTS The aqueous extract caused larval deaths, which varied from 16.4% to 88.4%. The efficiency of the powder varied from 29.2% to 82.8%. Storage did not interfere with the larvicidal efficiency of the aqueous extract of A. muscaria. CONCLUSIONS These results show the potential of A. muscariato control C. quinquefasciatus.

Efficient storage and management of radiographic images using a novel wavelet-based multiscale vector quantizer

NASA Astrophysics Data System (ADS)

Yang, Shuyu; Mitra, Sunanda

2002-05-01

Due to the huge volumes of radiographic images to be managed in hospitals, efficient compression techniques yielding no perceptual loss in the reconstructed images are becoming a requirement in the storage and management of such datasets. A wavelet-based multi-scale vector quantization scheme that generates a global codebook for efficient storage and transmission of medical images is presented in this paper. The results obtained show that even at low bit rates one is able to obtain reconstructed images with perceptual quality higher than that of the state-of-the-art scalar quantization method, the set partitioning in hierarchical trees.

Light storage in a cold atomic ensemble with a high optical depth

NASA Astrophysics Data System (ADS)

Park, Kwang-Kyoon; Chough, Young-Tak; Kim, Yoon-Ho

2017-06-01

A quantum memory with a high storage efficiency and a long coherence time is an essential element in quantum information applications. Here, we report our recent development of an optical quantum memory with a rubidium-87 cold atom ensemble. By increasing the optical depth of the medium, we have achieved a storage efficiency of 65% and a coherence time of 51 μs for a weak laser pulse. The result of a numerical analysis based on the Maxwell-Bloch equations agrees well with the experimental results. Our result paves the way toward an efficient optical quantum memory and may find applications in photonic quantum information processing.

The reliability and internal consistency of one-shot and flicker change detection for measuring individual differences in visual working memory capacity.

PubMed

Pailian, Hrag; Halberda, Justin

2015-04-01

We investigated the psychometric properties of the one-shot change detection task for estimating visual working memory (VWM) storage capacity-and also introduced and tested an alternative flicker change detection task for estimating these limits. In three experiments, we found that the one-shot whole-display task returns estimates of VWM storage capacity (K) that are unreliable across set sizes-suggesting that the whole-display task is measuring different things at different set sizes. In two additional experiments, we found that the one-shot single-probe variant shows improvements in the reliability and consistency of K estimates. In another additional experiment, we found that a one-shot whole-display-with-click task (requiring target localization) also showed improvements in reliability and consistency. The latter results suggest that the one-shot task can return reliable and consistent estimates of VWM storage capacity (K), and they highlight the possibility that the requirement to localize the changed target is what engenders this enhancement. Through a final series of four experiments, we introduced and tested an alternative flicker change detection method that also requires the observer to localize the changing target and that generates, from response times, an estimate of VWM storage capacity (K). We found that estimates of K from the flicker task correlated with estimates from the traditional one-shot task and also had high reliability and consistency. We highlight the flicker method's ability to estimate executive functions as well as VWM storage capacity, and discuss the potential for measuring multiple abilities with the one-shot and flicker tasks.

ENERGY EFFICIENCY AND ENVIRONMENTALLY FRIENDLY DISTRIBUTED ENERGY STORAGE BATTERY

DOE Office of Scientific and Technical Information (OSTI.GOV)

LANDI, J.T.; PLIVELICH, R.F.

2006-04-30

Electro Energy, Inc. conducted a research project to develop an energy efficient and environmentally friendly bipolar Ni-MH battery for distributed energy storage applications. Rechargeable batteries with long life and low cost potentially play a significant role by reducing electricity cost and pollution. A rechargeable battery functions as a reservoir for storage for electrical energy, carries energy for portable applications, or can provide peaking energy when a demand for electrical power exceeds primary generating capabilities.

Finite-size effect on optimal efficiency of heat engines.

PubMed

Tajima, Hiroyasu; Hayashi, Masahito

2017-07-01

The optimal efficiency of quantum (or classical) heat engines whose heat baths are n-particle systems is given by the strong large deviation. We give the optimal work extraction process as a concrete energy-preserving unitary time evolution among the heat baths and the work storage. We show that our optimal work extraction turns the disordered energy of the heat baths to the ordered energy of the work storage, by evaluating the ratio of the entropy difference to the energy difference in the heat baths and the work storage, respectively. By comparing the statistical mechanical optimal efficiency with the macroscopic thermodynamic bound, we evaluate the accuracy of the macroscopic thermodynamics with finite-size heat baths from the statistical mechanical viewpoint. We also evaluate the quantum coherence effect on the optimal efficiency of the cycle processes without restricting their cycle time by comparing the classical and quantum optimal efficiencies.

Highly efficient hydrogen storage system based on ammonium bicarbonate/formate redox equilibrium over palladium nanocatalysts.

PubMed

Su, Ji; Yang, Lisha; Lu, Mi; Lin, Hongfei

2015-03-01

A highly efficient, reversible hydrogen storage-evolution process has been developed based on the ammonium bicarbonate/formate redox equilibrium over the same carbon-supported palladium nanocatalyst. This heterogeneously catalyzed hydrogen storage system is comparable to the counterpart homogeneous systems and has shown fast reaction kinetics of both the hydrogenation of ammonium bicarbonate and the dehydrogenation of ammonium formate under mild operating conditions. By adjusting temperature and pressure, the extent of hydrogen storage and evolution can be well controlled in the same catalytic system. Moreover, the hydrogen storage system based on aqueous-phase ammonium formate is advantageous owing to its high volumetric energy density. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Highly Efficient Coherent Optical Memory Based on Electromagnetically Induced Transparency

NASA Astrophysics Data System (ADS)

Hsiao, Ya-Fen; Tsai, Pin-Ju; Chen, Hung-Shiue; Lin, Sheng-Xiang; Hung, Chih-Chiao; Lee, Chih-Hsi; Chen, Yi-Hsin; Chen, Yong-Fan; Yu, Ite A.; Chen, Ying-Cheng

2018-05-01

Quantum memory is an important component in the long-distance quantum communication based on the quantum repeater protocol. To outperform the direct transmission of photons with quantum repeaters, it is crucial to develop quantum memories with high fidelity, high efficiency and a long storage time. Here, we achieve a storage efficiency of 92.0 (1.5)% for a coherent optical memory based on the electromagnetically induced transparency scheme in optically dense cold atomic media. We also obtain a useful time-bandwidth product of 1200, considering only storage where the retrieval efficiency remains above 50%. Both are the best record to date in all kinds of schemes for the realization of optical memory. Our work significantly advances the pursuit of a high-performance optical memory and should have important applications in quantum information science.

Highly Efficient Coherent Optical Memory Based on Electromagnetically Induced Transparency.

PubMed

Hsiao, Ya-Fen; Tsai, Pin-Ju; Chen, Hung-Shiue; Lin, Sheng-Xiang; Hung, Chih-Chiao; Lee, Chih-Hsi; Chen, Yi-Hsin; Chen, Yong-Fan; Yu, Ite A; Chen, Ying-Cheng

2018-05-04

Quantum memory is an important component in the long-distance quantum communication based on the quantum repeater protocol. To outperform the direct transmission of photons with quantum repeaters, it is crucial to develop quantum memories with high fidelity, high efficiency and a long storage time. Here, we achieve a storage efficiency of 92.0 (1.5)% for a coherent optical memory based on the electromagnetically induced transparency scheme in optically dense cold atomic media. We also obtain a useful time-bandwidth product of 1200, considering only storage where the retrieval efficiency remains above 50%. Both are the best record to date in all kinds of schemes for the realization of optical memory. Our work significantly advances the pursuit of a high-performance optical memory and should have important applications in quantum information science.

Efficient secure-channel free public key encryption with keyword search for EMRs in cloud storage.

PubMed

Guo, Lifeng; Yau, Wei-Chuen

2015-02-01

Searchable encryption is an important cryptographic primitive that enables privacy-preserving keyword search on encrypted electronic medical records (EMRs) in cloud storage. Efficiency of such searchable encryption in a medical cloud storage system is very crucial as it involves client platforms such as smartphones or tablets that only have constrained computing power and resources. In this paper, we propose an efficient secure-channel free public key encryption with keyword search (SCF-PEKS) scheme that is proven secure in the standard model. We show that our SCF-PEKS scheme is not only secure against chosen keyword and ciphertext attacks (IND-SCF-CKCA), but also secure against keyword guessing attacks (IND-KGA). Furthermore, our proposed scheme is more efficient than other recent SCF-PEKS schemes in the literature.

Dynamics of in vivo power output and efficiency of Nasonia asynchronous flight muscle.

PubMed

Lehmann, Fritz-Olaf; Heymann, Nicole

2006-06-25

By simultaneously measuring aerodynamic performance, wing kinematics, and metabolic activity, we have estimated the in vivo limits of mechanical power production and efficiency of the asynchronous flight muscle (IFM) in three species of ectoparasitoid wasps genus Nasonia (N. giraulti, N. longicornis, and N. vitripennis). The 0.6 mg animals were flown under tethered flight conditions in a flight simulator that allowed modulation of power production by employing an open-loop visual stimulation technique. At maximum locomotor capacity, flight muscles of Nasonia are capable to sustain 72.2 +/- 18.3 W kg(-1) muscle mechanical power at a chemo-mechanical conversion efficiency of approximately 9.8 +/- 0.9%. Within the working range of the locomotor system, profile power requirement for flight dominates induced power requirement suggesting that the cost to overcome wing drag places the primary limit on overall flight performance. Since inertial power is only approximately 25% of the sum of induced and profile power requirements, Nasonia spp. may not benefit from elastic energy storage during wing deceleration phases. A comparison between wing size-polymorphic males revealed that wing size reduction is accompanied by a decrease in total flight muscle volume, muscle mass-specific mechanical power production, and total flight efficiency. In animals with small wings maximum total flight efficiency is below 0.5%. The aerodynamic and power estimates reported here for Nasonia are comparable to values reported previously for the fruit fly Drosophila flying under similar experimental conditions, while muscle efficiency of the tiny wasp is more at the lower end of values published for various other insects.

Cycling capacity recovery effect: A coulombic efficiency and post-mortem study

NASA Astrophysics Data System (ADS)

Wilhelm, Jörn; Seidlmayer, Stefan; Keil, Peter; Schuster, Jörg; Kriele, Armin; Gilles, Ralph; Jossen, Andreas

2017-10-01

The analysis of lithium-ion battery aging relies on correct differentiation between irreversible and reversible capacity changes. Anode overhang regions have been observed to influence Coulombic Efficiency (CE) measurements through lithium diffusion into and out of these areas, complicating precise capacity determination. This work presents an analysis of the extent of graphite anode overhang lithiation after calendar storage by means of local X-ray diffraction (XRD), CE measurements, and color change analysis. We found LiC12 lithiation of the anode overhang area after 20 month storage at 40 °C at high state of charge (SoC) and partial lithiation (LiC18) at medium SoC storage at 40 °C and 25 °C. Graphite color changes in the overhang areas are observed and consistent with the state of lithiation measured by XRD. Coulombic efficiencies greater than unity and increasing capacity during 1200 h of cycling are detected for high SoC storage cells. The capacity difference between high and low storage SoC batteries decreases by up to 40 mAh (3.6% of nominal capacity) after cycling compared to tests directly after storage. Consequently, the size of the anode overhang areas as well as the battery storage temperature and duration need to be considered in CE analysis and state of health assessment.

Underground storage of imported water in the San Gorgonio Pass area, southern California

USGS Publications Warehouse

Bloyd, Richard M.

1971-01-01

The San Gorgonio Pass ground-water basin is divided into the Beaumont, Banning, Cabazon, San Timoteo, South Beaumont, Banning Bench, and Singleton storage units. The Beaumont storage unit, centrally located in the agency area, is the largest in volume of the storage units. Estimated long-term average annual precipitation in the San Gorgonio Pass Water Agency drainage area is 332,000 acre-feet, and estimated average annual recoverable water is 24,000 acre-feet, less than 10 percent of the total precipitation. Estimated average annual surface outflow is 1,700 acre-feet, and estimated average annual ground-water recharge is 22,000 acre-feet. Projecting tack to probable steady-state conditions, of the 22.000 acre-feet of recharge, 16,003 acre-feet per year became subsurface outflow into Coachella Valley, 6,000 acre-feet into the Redlands area, and 220 acre-feet into Potrero Canyon. After extensive development, estimated subsurface outflow from the area in 1967 was 6,000 acre-feet into the Redlands area, 220 acre-feet into Potrero Canyon, and 800 acre-feet into the fault systems south of the Banning storage unit, unwatered during construction of a tunnel. Subsurface outflow into Coachella Valley in 1967 is probably less than 50 percent of the steady-state flow. An anticipated 17,000 .acre-feet of water per year will be imported by 1980. Information developed in this study indicates it is technically feasible to store imported water in the eastern part of the Beaumont storage unit without causing waterlogging in the storage area and without losing any significant quantity of stored water.

Advanced Power Sources for Space Missions

DTIC Science & Technology

1989-01-01

Range indicate that extremely high power levels hav- ing fast time-ramping capabilities must be provided during the tests. Only highly efficient prime...system efficiency results from advantages in thermal storage versus battery storage and from the increased conversion efficiency of a solar-dynamic... thermal manage- ment, power flow, and voltage levels, and may be in the same power range already experienced in the very- high -power radar and fusion

Thermodynamic Performance and Cost Optimization of a Novel Hybrid Thermal-Compressed Air Energy Storage System Design

DOE Office of Scientific and Technical Information (OSTI.GOV)

Houssainy, Sammy; Janbozorgi, Mohammad; Kavehpour, Pirouz

Compressed Air Energy Storage (CAES) can potentially allow renewable energy sources to meet electricity demands as reliably as coal-fired power plants. However, conventional CAES systems rely on the combustion of natural gas, require large storage volumes, and operate at high pressures, which possess inherent problems such as high costs, strict geological locations, and the production of greenhouse gas emissions. A novel and patented hybrid thermal-compressed air energy storage (HT-CAES) design is presented which allows a portion of the available energy, from the grid or renewable sources, to operate a compressor and the remainder to be converted and stored in themore » form of heat, through joule heating in a sensible thermal storage medium. The HT-CAES design incudes a turbocharger unit that provides supplementary mass flow rate alongside the air storage. The hybrid design and the addition of a turbocharger have the beneficial effect of mitigating the shortcomings of conventional CAES systems and its derivatives by eliminating combustion emissions and reducing storage volumes, operating pressures, and costs. Storage efficiency and cost are the two key factors, which upon integration with renewable energies would allow the sources to operate as independent forms of sustainable energy. The potential of the HT-CAES design is illustrated through a thermodynamic optimization study, which outlines key variables that have a major impact on the performance and economics of the storage system. The optimization analysis quantifies the required distribution of energy between thermal and compressed air energy storage, for maximum efficiency, and for minimum cost. This study provides a roundtrip energy and exergy efficiency map of the storage system and illustrates a trade off that exists between its capital cost and performance.« less

Efficient Transfer Entropy Analysis of Non-Stationary Neural Time Series

PubMed Central

Vicente, Raul; Díaz-Pernas, Francisco J.; Wibral, Michael

2014-01-01

Information theory allows us to investigate information processing in neural systems in terms of information transfer, storage and modification. Especially the measure of information transfer, transfer entropy, has seen a dramatic surge of interest in neuroscience. Estimating transfer entropy from two processes requires the observation of multiple realizations of these processes to estimate associated probability density functions. To obtain these necessary observations, available estimators typically assume stationarity of processes to allow pooling of observations over time. This assumption however, is a major obstacle to the application of these estimators in neuroscience as observed processes are often non-stationary. As a solution, Gomez-Herrero and colleagues theoretically showed that the stationarity assumption may be avoided by estimating transfer entropy from an ensemble of realizations. Such an ensemble of realizations is often readily available in neuroscience experiments in the form of experimental trials. Thus, in this work we combine the ensemble method with a recently proposed transfer entropy estimator to make transfer entropy estimation applicable to non-stationary time series. We present an efficient implementation of the approach that is suitable for the increased computational demand of the ensemble method's practical application. In particular, we use a massively parallel implementation for a graphics processing unit to handle the computationally most heavy aspects of the ensemble method for transfer entropy estimation. We test the performance and robustness of our implementation on data from numerical simulations of stochastic processes. We also demonstrate the applicability of the ensemble method to magnetoencephalographic data. While we mainly evaluate the proposed method for neuroscience data, we expect it to be applicable in a variety of fields that are concerned with the analysis of information transfer in complex biological, social, and artificial systems. PMID:25068489

Standard operating procedures for standardized mass rearing of the dengue and chikungunya vectors Aedes aegypti and Aedes albopictus (Diptera: Culicidae) - II - Egg storage and hatching.

PubMed

Zheng, Min-Lin; Zhang, Dong-Jing; Damiens, David D; Lees, Rosemary Susan; Gilles, Jeremie R L

2015-06-26

Management of large quantities of eggs will be a crucial aspect of the efficient and sustainable mass production of mosquitoes for programmes with a Sterile Insect Technique component. The efficiency of different hatching media and effectiveness of long term storage methods are presented here. The effect on hatch rate of storage duration and three hatching media was analysed: deionized water, boiled deionized water and a bacterial broth, using Two-way ANOVA and Post hoc Tukey tests, and the Pearson correlation coefficient was used to find the effect on the proportion of collapsed eggs. Two long term storage methods were also tested: conventional storage (egg paper strips stored in zip lock bags within a sealed plastic box), and water storage (egg papers in a covered plastic cup with deionized water). Regression analyses were used to find the effect of water storage and storage duration on hatch rate. Both species hatched most efficiently in bacterial broth. Few eggs hatched in deionized water, and pre-boiling the water increased the hatch rate of Ae. aegypti, but not Ae. albopictus. A hatch rate greater than 80% was obtained after 10 weeks of conventional storage in Ae. aegypti and 11 weeks in Ae. albopictus. After this period, hatching decreased dramatically; no eggs hatched after 24 weeks. Storing eggs in water produced an 85% hatch rate after 5 months in both species. A small but significant proportion of eggs hatched in the water, probably due to combined effects of natural deoxygenation of the water over time and the natural instalment hatching typical of the species. The demonstrated efficiency of the bacterial broth hatching medium for both Ae. albopictus and Ae. aegypti facilitates mass production of these two important vector species in the same facility, with use of a common hatching medium reducing cost and operational complexity. Similarly the increased hatch rate of eggs stored in water would allow greater flexibility of egg management in a large programme over the medium term, particularly if oxygenation of the water by bubbling oxygen through the storage tray could be applied to prevent hatching during storage.

Efficient Solar Energy Harvesting and Storage through a Robust Photocatalyst Driving Reversible Redox Reactions.

PubMed

Zhou, Yangen; Zhang, Shun; Ding, Yu; Zhang, Leyuan; Zhang, Changkun; Zhang, Xiaohong; Zhao, Yu; Yu, Guihua

2018-06-14

Simultaneous solar energy conversion and storage is receiving increasing interest for better utilization of the abundant yet intermittently available sunlight. Photoelectrodes driving nonspontaneous reversible redox reactions in solar-powered redox cells (SPRCs), which can deliver energy via the corresponding reverse reactions, present a cost-effective and promising approach for direct solar energy harvesting and storage. However, the lack of photoelectrodes having both high conversion efficiency and high durability becomes a bottleneck that hampers practical applications of SPRCs. Here, it is shown that a WO 3 -decorated BiVO 4 photoanode, without the need of extra electrocatalysts, can enable a single-photocatalyst-driven SPRC with a solar-to-output energy conversion efficiency as high as 1.25%. This SPRC presents stable performance over 20 solar energy storage/delivery cycles. The high efficiency and stability are attributed to the rapid redox reactions, the well-matched energy level, and the efficient light harvesting and charge separation of the prepared BiVO 4 . This demonstrated device system represents a potential alternative toward the development of low-cost, durable, and easy-to-implement solar energy technologies. © 2018 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

3-D transient hydraulic tomography in unconfined aquifers with fast drainage response

NASA Astrophysics Data System (ADS)

Cardiff, M.; Barrash, W.

2011-12-01

We investigate, through numerical experiments, the viability of three-dimensional transient hydraulic tomography (3DTHT) for identifying the spatial distribution of groundwater flow parameters (primarily, hydraulic conductivity K) in permeable, unconfined aquifers. To invert the large amount of transient data collected from 3DTHT surveys, we utilize an iterative geostatistical inversion strategy in which outer iterations progressively increase the number of data points fitted and inner iterations solve the quasi-linear geostatistical formulas of Kitanidis. In order to base our numerical experiments around realistic scenarios, we utilize pumping rates, geometries, and test lengths similar to those attainable during 3DTHT field campaigns performed at the Boise Hydrogeophysical Research Site (BHRS). We also utilize hydrologic parameters that are similar to those observed at the BHRS and in other unconsolidated, unconfined fluvial aquifers. In addition to estimating K, we test the ability of 3DTHT to estimate both average storage values (specific storage Ss and specific yield Sy) as well as spatial variability in storage coefficients. The effects of model conceptualization errors during unconfined 3DTHT are investigated including: (1) assuming constant storage coefficients during inversion and (2) assuming stationary geostatistical parameter variability. Overall, our findings indicate that estimation of K is slightly degraded if storage parameters must be jointly estimated, but that this effect is quite small compared with the degradation of estimates due to violation of "structural" geostatistical assumptions. Practically, we find for our scenarios that assuming constant storage values during inversion does not appear to have a significant effect on K estimates or uncertainty bounds.

Electrospinning of Nanofibers for Energy Applications

PubMed Central

Sun, Guiru; Sun, Liqun; Xie, Haiming; Liu, Jia

2016-01-01

With global concerns about the shortage of fossil fuels and environmental issues, the development of efficient and clean energy storage devices has been drastically accelerated. Nanofibers are used widely for energy storage devices due to their high surface areas and porosities. Electrospinning is a versatile and efficient fabrication method for nanofibers. In this review, we mainly focus on the application of electrospun nanofibers on energy storage, such as lithium batteries, fuel cells, dye-sensitized solar cells and supercapacitors. The structure and properties of nanofibers are also summarized systematically. The special morphology of nanofibers prepared by electrospinning is significant to the functional materials for energy storage. PMID:28335256

Heat-pump cool storage in a clathrate of freon

NASA Astrophysics Data System (ADS)

Tomlinson, J. J.

Presented are the analytical description and assessment of a unique heat pump/storage system in which the conventional evaporator of the vapor compression cycle is replaced by a highly efficient direct contract crystallizer. The thermal storage technique requires the formation of a refrigerant gas hydrate (a clathrate) and exploits an enthalpy of reaction comparable to the heat of fusion of ice. Additional system operational benefits include cool storage at the favorable temperatures of 4 to 7 C (40 to 45 F), and highly efficient heat transfer ates afforded by he direct contact mechanism. In addition, the experimental approach underway at ORNL to study such a system is discussed.

Investigation of the charge boost technology for the efficiency increase of closed sorption thermal energy storage systems

NASA Astrophysics Data System (ADS)

Rohringer, C.; Engel, G.; Köll, R.; Wagner, W.; van Helden, W.

2017-10-01

The inclusion of solar thermal energy into energy systems requires storage possibilities to overcome the gap between supply and demand. Storage of thermal energy with closed sorption thermal energy systems has the advantage of low thermal losses and high energy density. However, the efficiency of these systems needs yet to be increased to become competitive on the market. In this paper, the so-called “charge boost technology” is developed and tested via experiments as a new concept for the efficiency increase of compact thermal energy storages. The main benefit of the charge boost technology is that it can reach a defined state of charge for sorption thermal energy storages at lower temperature levels than classic pure desorption processes. Experiments are conducted to provide a proof of principle for this concept. The results show that the charge boost technology does function as predicted and is a viable option for further improvement of sorption thermal energy storages. Subsequently, a new process application is developed by the author with strong focus on the utilization of the advantages of the charge boost technology over conventional desorption processes. After completion of the conceptual design, the theoretical calculations are validated via experiments.

Ring profiler: a new method for estimating tree-ring density for improved estimates of carbon storage

Treesearch

David W. Vahey; C. Tim Scott; J.Y. Zhu; Kenneth E. Skog

2012-01-01

Methods for estimating present and future carbon storage in trees and forests rely on measurements or estimates of tree volume or volume growth multiplied by specific gravity. Wood density can vary by tree ring and height in a tree. If data on density by tree ring could be obtained and linked to tree size and stand characteristics, it would be possible to more...

Current forest and woodland carbon storage and flux in California: An estimate for the 2010 statewide assessment

Treesearch

Timothy A. Robards

2012-01-01

This study used USDA Forest Service Forest Inventory and Analysis (FIA) plot data, forest growth models, wildland fire emission estimates and timber harvest data to estimate the live tree carbon storage and flux of California's forests and woodlands. Approximately 30 Tg C02e per year was estimated as the annual flux for all California forests. The forest inventory...

Fundamental Challenges for Modeling Electrochemical Energy Storage Systems at the Atomic Scale.

PubMed

Groß, Axel

2018-04-23

There is a strong need to improve the efficiency of electrochemical energy storage, but progress is hampered by significant technological and scientific challenges. This review describes the potential contribution of atomic-scale modeling to the development of more efficient batteries, with a particular focus on first-principles electronic structure calculations. Numerical and theoretical obstacles are discussed, along with ways to overcome them, and some recent examples are presented illustrating the insights into electrochemical energy storage that can be gained from quantum chemical studies.

Space power system utilizing Fresnel lenses for solar power and also thermal energy storage

NASA Technical Reports Server (NTRS)

Turner, R. H.

1983-01-01

A solar power plant suitable for earth orbits passing through Van Allen radiation belts is described. The solar-to-electricity conversion efficiency is estimated to be around 9 percent, and the expected power-to-weight ratio is competitive with photovoltaic arrays. The system is designed to be self-contained, to be indifferent to radiation belt exposures, store energy for periods when the orbiting system is in earth shadow (so that power generation is contant), have no moving parts and no working fluids, and be robust against micrometeorite attack. No electrical batteries are required.

Hybrid Skyshine Calculations for Complex Neutron and Gamma-Ray Sources

DOE Office of Scientific and Technical Information (OSTI.GOV)

Shultis, J. Kenneth

2000-10-15

A two-step hybrid method is described for computationally efficient estimation of neutron and gamma-ray skyshine doses far from a shielded source. First, the energy and angular dependence of radiation escaping into the atmosphere from a source containment is determined by a detailed transport model such as MCNP. Then, an effective point source with this energy and angular dependence is used in the integral line-beam method to transport the radiation through the atmosphere up to 2500 m from the source. An example spent-fuel storage cask is analyzed with this hybrid method and compared to detailed MCNP skyshine calculations.

Towards rewritable multilevel optical data storage in single nanocrystals.

PubMed

Riesen, Nicolas; Pan, Xuanzhao; Badek, Kate; Ruan, Yinlan; Monro, Tanya M; Zhao, Jiangbo; Ebendorff-Heidepriem, Heike; Riesen, Hans

2018-04-30

Novel approaches for digital data storage are imperative, as storage capacities are drastically being outpaced by the exponential growth in data generation. Optical data storage represents the most promising alternative to traditional magnetic and solid-state data storage. In this paper, a novel and energy efficient approach to optical data storage using rare-earth ion doped inorganic insulators is demonstrated. In particular, the nanocrystalline alkaline earth halide BaFCl:Sm is shown to provide great potential for multilevel optical data storage. Proof-of-concept demonstrations reveal for the first time that these phosphors could be used for rewritable, multilevel optical data storage on the physical dimensions of a single nanocrystal. Multilevel information storage is based on the very efficient and reversible conversion of Sm 3+ to Sm 2+ ions upon exposure to UV-C light. The stored information is then read-out using confocal optics by employing the photoluminescence of the Sm 2+ ions in the nanocrystals, with the signal strength depending on the UV-C fluence used during the write step. The latter serves as the mechanism for multilevel data storage in the individual nanocrystals, as demonstrated in this paper. This data storage platform has the potential to be extended to 2D and 3D memory for storage densities that could potentially approach petabyte/cm 3 levels.

The sensitivity of terrestrial carbon storage to historical climate variability and atmospheric CO2 in the United States

USGS Publications Warehouse

Tian, H.; Melillo, J.M.; Kicklighter, D.W.; McGuire, A.D.; Helfrich, J.

1999-01-01

We use the Terrestrial Ecosystem Model (TEM, Version 4.1) and the land cover data set of the international geosphere-biosphere program to investigate how increasing atmospheric CO2 concentration and climate variability during 1900-1994 affect the carbon storage of terrestrial ecosystems in the conterminous USA, and how carbon storage has been affected by land-use change. The estimates of TEM indicate that over the past 95 years a combination of increasing atmospheric CO2 with historical temperature and precipitation variability causes a 4.2% (4.3 Pg C) decrease in total carbon storage of potential vegetation in the conterminous US, with vegetation carbon decreasing by 7.2% (3.2 Pg C) and soil organic carbon decreasing by 1.9% (1.1 Pg C). Several dry periods including the 1930s and 1950s are responsible for the loss of carbon storage. Our factorial experiments indicate that precipitation variability alone decreases total carbon storage by 9.5%. Temperature variability alone does not significantly affect carbon storage. The effect of CO2 fertilization alone increases total carbon storage by 4.4%. The effects of increasing atmospheric CO2 and climate variability are not additive. Interactions among CO2, temperature and precipitation increase total carbon storage by 1.1%. Our study also shows substantial year-to-year variations in net carbon exchange between the atmosphere and terrestrial ecosystems due to climate variability. Since the 1960s, we estimate these terrestrial ecosystems have acted primarily as a sink of atmospheric CO2 as a result of wetter weather and higher atmospheric CO2 concentrations. For the 1980s, we estimate the natural terrestrial ecosystems, excluding cropland and urban areas, of the conterminous US have accumulated 78.2 Tg C yr-1 because of the combined effect of increasing atmospheric CO2 and climate variability. For the conterminous US, we estimate that the conversion of natural ecosystems to cropland and urban areas has caused a 18.2% (17.7 Pg C) reduction in total carbon storage from that estimated for potential vegetation. The carbon sink capacity of natural terrestrial ecosystems in the conterminous US is about 69% of that estimated for potential vegetation.

Estimation of carbon storage based on individual tree detection in Pinus densiflora stands using a fusion of aerial photography and LiDAR data.

PubMed

Kim, So-Ra; Kwak, Doo-Ahn; Lee, Woo-Kyun; oLee, Woo-Kyun; Son, Yowhan; Bae, Sang-Won; Kim, Choonsig; Yoo, Seongjin

2010-07-01

The objective of this study was to estimate the carbon storage capacity of Pinus densiflora stands using remotely sensed data by combining digital aerial photography with light detection and ranging (LiDAR) data. A digital canopy model (DCM), generated from the LiDAR data, was combined with aerial photography for segmenting crowns of individual trees. To eliminate errors in over and under-segmentation, the combined image was smoothed using a Gaussian filtering method. The processed image was then segmented into individual trees using a marker-controlled watershed segmentation method. After measuring the crown area from the segmented individual trees, the individual tree diameter at breast height (DBH) was estimated using a regression function developed from the relationship observed between the field-measured DBH and crown area. The above ground biomass of individual trees could be calculated by an image-derived DBH using a regression function developed by the Korea Forest Research Institute. The carbon storage, based on individual trees, was estimated by simple multiplication using the carbon conversion index (0.5), as suggested in guidelines from the Intergovernmental Panel on Climate Change. The mean carbon storage per individual tree was estimated and then compared with the field-measured value. This study suggested that the biomass and carbon storage in a large forest area can be effectively estimated using aerial photographs and LiDAR data.

Establishing MICHCARB, a geological carbon sequestration research and education center for Michigan, implemented through the Michigan Geological Repository for Research and Education, part of the Department of Geosciences at Western Michigan University

DOE Office of Scientific and Technical Information (OSTI.GOV)

Barnes, David A.; Harrison, William B.

The Michigan Geological Repository for Research and Education (MGRRE), part of the Department of Geosciences at Western Michigan University (WMU) at Kalamazoo, Michigan, established MichCarb—a geological carbon sequestration resource center by: • Archiving and maintaining a current reference collection of carbon sequestration published literature • Developing statewide and site-specific digital research databases for Michigan’s deep geological formations relevant to CO2 storage, containment and potential for enhanced oil recovery • Producing maps and tables of physical properties as components of these databases • Compiling all information into a digital atlas • Conducting geologic and fluid flow modeling to address specific predictivemore » uses of CO2 storage and enhanced oil recovery, including compiling data for geological and fluid flow models, formulating models, integrating data, and running the models; applying models to specific predictive uses of CO2 storage and enhanced oil recovery • Conducting technical research on CO2 sequestration and enhanced oil recovery through basic and applied research of characterizing Michigan oil and gas and saline reservoirs for CO2 storage potential volume, injectivity and containment. Based on our research, we have concluded that the Michigan Basin has excellent saline aquifer (residual entrapment) and CO2/Enhanced oil recovery related (CO2/EOR; buoyant entrapment) geological carbon sequestration potential with substantial, associated incremental oil production potential. These storage reservoirs possess at least satisfactory injectivity and reliable, permanent containment resulting from associated, thick, low permeability confining layers. Saline aquifer storage resource estimates in the two major residual entrapment, reservoir target zones (Lower Paleozoic Sandstone and Middle Paleozoic carbonate and sandstone reservoirs) are in excess of 70-80 Gmt (at an overall 10% storage efficiency factor; an approximately P50 probability range for all formations using DOE-NETL, 2010, storage resource estimation methodology). Incremental oil production resulting from successful implementation of CO2/EOR for the highest potential Middle Paleozoic reef reservoirs (Silurian, Northern Niagaran Reef trend) in Michigan is estimated at 130 to over 200 MMBO (22-33 Mm3). In addition, between 200 and 400 Mmt of CO2 could be sequestered in the course of successful deployment of CO2/EOR in the northern reef trend’s largest depleted (primary production) oil fields (those that have produced in excess of 500,000 BO; 80,000 m3of oil). • Effecting technology transfer to members of industry and governmental agencies by establishing an Internet Website at which all data, reports and results are accessible; publishing results in relevant journals; conducting technology transfer workshops as part of our role as the Michigan Center of the Petroleum Technology Transfer Council or any successor organization.« less

Chemical hydrogen storage material property guidelines for automotive applications

NASA Astrophysics Data System (ADS)

Semelsberger, Troy A.; Brooks, Kriston P.

2015-04-01

Chemical hydrogen storage is the sought after hydrogen storage media for automotive applications because of the expected low pressure operation (<20 atm), moderate temperature operation (<200 °C), system gravimetric capacities (>0.05 kg H2/kgsystem), and system volumetric capacities (>0.05 kg H2/Lsystem). Currently, the primary shortcomings of chemical hydrogen storage are regeneration efficiency, fuel cost and fuel phase (i.e., solid or slurry phase). Understanding the required material properties to meet the DOE Technical Targets for Onboard Hydrogen Storage Systems is a critical knowledge gap in the hydrogen storage research community. This study presents a set of fluid-phase chemical hydrogen storage material property guidelines for automotive applications meeting the 2017 DOE technical targets. Viable material properties were determined using a boiler-plate automotive system design. The fluid-phase chemical hydrogen storage media considered in this study were neat liquids, solutions, and non-settling homogeneous slurries. Material properties examined include kinetics, heats of reaction, fuel-cell impurities, gravimetric and volumetric hydrogen storage capacities, and regeneration efficiency. The material properties, although not exhaustive, are an essential first step in identifying viable chemical hydrogen storage material properties-and most important, their implications on system mass, system volume and system performance.

Reaction wheels for kinetic energy storage

NASA Astrophysics Data System (ADS)

Studer, P. A.

1984-11-01

In contrast to all existing reaction wheel implementations, an order of magnitude increase in speed can be obtained efficiently if power to the actuators can be recovered. This allows a combined attitude control-energy storage system to be developed with structure mounted reaction wheels. The feasibility of combining reaction wheels with energy storage wwheels is demonstrated. The power required for control torques is a function of wheel speed but this energy is not dissipated; it is stored in the wheel. The I(2)R loss resulting from a given torque is shown to be constant, independent of the design speed of the motor. What remains, in order to efficiently use high speed wheels (essential for energy storage) for control purposes, is to reduce rotational losses to acceptable levels. Progress was made in permanent magnet motor design for high speed operation. Variable field motors offer more control flexibility and efficiency over a broader speed range.

Reaction wheels for kinetic energy storage

NASA Technical Reports Server (NTRS)

Studer, P. A.

1984-01-01

In contrast to all existing reaction wheel implementations, an order of magnitude increase in speed can be obtained efficiently if power to the actuators can be recovered. This allows a combined attitude control-energy storage system to be developed with structure mounted reaction wheels. The feasibility of combining reaction wheels with energy storage wwheels is demonstrated. The power required for control torques is a function of wheel speed but this energy is not dissipated; it is stored in the wheel. The I(2)R loss resulting from a given torque is shown to be constant, independent of the design speed of the motor. What remains, in order to efficiently use high speed wheels (essential for energy storage) for control purposes, is to reduce rotational losses to acceptable levels. Progress was made in permanent magnet motor design for high speed operation. Variable field motors offer more control flexibility and efficiency over a broader speed range.

A chemistry and material perspective on lithium redox flow batteries towards high-density electrical energy storage.

PubMed

Zhao, Yu; Ding, Yu; Li, Yutao; Peng, Lele; Byon, Hye Ryung; Goodenough, John B; Yu, Guihua

2015-11-21

Electrical energy storage system such as secondary batteries is the principle power source for portable electronics, electric vehicles and stationary energy storage. As an emerging battery technology, Li-redox flow batteries inherit the advantageous features of modular design of conventional redox flow batteries and high voltage and energy efficiency of Li-ion batteries, showing great promise as efficient electrical energy storage system in transportation, commercial, and residential applications. The chemistry of lithium redox flow batteries with aqueous or non-aqueous electrolyte enables widened electrochemical potential window thus may provide much greater energy density and efficiency than conventional redox flow batteries based on proton chemistry. This Review summarizes the design rationale, fundamentals and characterization of Li-redox flow batteries from a chemistry and material perspective, with particular emphasis on the new chemistries and materials. The latest advances and associated challenges/opportunities are comprehensively discussed.

Integrated Photoelectrochemical Solar Energy Conversion and Organic Redox Flow Battery Devices.

PubMed

Li, Wenjie; Fu, Hui-Chun; Li, Linsen; Cabán-Acevedo, Miguel; He, Jr-Hau; Jin, Song

2016-10-10

Building on regenerative photoelectrochemical solar cells and emerging electrochemical redox flow batteries (RFBs), more efficient, scalable, compact, and cost-effective hybrid energy conversion and storage devices could be realized. An integrated photoelectrochemical solar energy conversion and electrochemical storage device is developed by integrating regenerative silicon solar cells and 9,10-anthraquinone-2,7-disulfonic acid (AQDS)/1,2-benzoquinone-3,5-disulfonic acid (BQDS) RFBs. The device can be directly charged by solar light without external bias, and discharged like normal RFBs with an energy storage density of 1.15 Wh L -1 and a solar-to-output electricity efficiency (SOEE) of 1.7 % over many cycles. The concept exploits a previously undeveloped design connecting two major energy technologies and promises a general approach for storing solar energy electrochemically with high theoretical storage capacity and efficiency. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Methods and devices for determining quality of services of storage systems

DOEpatents

Seelam, Seetharami R [Yorktown Heights, NY; Teller, Patricia J [Las Cruces, NM

2012-01-17

Methods and systems for allowing access to computer storage systems. Multiple requests from multiple applications can be received and processed efficiently to allow traffic from multiple customers to access the storage system concurrently.

Volume Holographic Storage of Digital Data Implemented in Photorefractive Media

NASA Astrophysics Data System (ADS)

Heanue, John Frederick

A holographic data storage system is fundamentally different from conventional storage devices. Information is recorded in a volume, rather than on a two-dimensional surface. Data is transferred in parallel, on a page-by -page basis, rather than serially. These properties, combined with a limited need for mechanical motion, lead to the potential for a storage system with high capacity, fast transfer rate, and short access time. The majority of previous volume holographic storage experiments have involved direct storage and retrieval of pictorial information. Success in the development of a practical holographic storage device requires an understanding of the performance capabilities of a digital system. This thesis presents a number of contributions toward this goal. A description of light diffraction from volume gratings is given. The results are used as the basis for a theoretical and numerical analysis of interpage crosstalk in both angular and wavelength multiplexed holographic storage. An analysis of photorefractive grating formation in photovoltaic media such as lithium niobate is presented along with steady-state expressions for the space-charge field in thermal fixing. Thermal fixing by room temperature recording followed by ion compensation at elevated temperatures is compared to simultaneous recording and compensation at high temperature. In particular, the tradeoff between diffraction efficiency and incomplete Bragg matching is evaluated. An experimental investigation of orthogonal phase code multiplexing is described. Two unique capabilities, the ability to perform arithmetic operations on stored data pages optically, rather than electronically, and encrypted data storage, are demonstrated. A comparison of digital signal representations, or channel codes, is carried out. The codes are compared in terms of bit-error rate performance at constant capacity. A well-known one-dimensional digital detection technique, maximum likelihood sequence estimation, is extended for use in a two-dimensional page format memory. The effectiveness of the technique in a system corrupted by intersymbol interference is investigated both experimentally and through numerical simulations. The experimental implementation of a fully-automated multiple page digital holographic storage system is described. Finally, projections of the performance limits of holographic data storage are made taking into account typical noise sources.

MrBayes tgMC3++: A High Performance and Resource-Efficient GPU-Oriented Phylogenetic Analysis Method.

PubMed

Ling, Cheng; Hamada, Tsuyoshi; Gao, Jingyang; Zhao, Guoguang; Sun, Donghong; Shi, Weifeng

2016-01-01

MrBayes is a widespread phylogenetic inference tool harnessing empirical evolutionary models and Bayesian statistics. However, the computational cost on the likelihood estimation is very expensive, resulting in undesirably long execution time. Although a number of multi-threaded optimizations have been proposed to speed up MrBayes, there are bottlenecks that severely limit the GPU thread-level parallelism of likelihood estimations. This study proposes a high performance and resource-efficient method for GPU-oriented parallelization of likelihood estimations. Instead of having to rely on empirical programming, the proposed novel decomposition storage model implements high performance data transfers implicitly. In terms of performance improvement, a speedup factor of up to 178 can be achieved on the analysis of simulated datasets by four Tesla K40 cards. In comparison to the other publicly available GPU-oriented MrBayes, the tgMC 3 ++ method (proposed herein) outperforms the tgMC 3 (v1.0), nMC 3 (v2.1.1) and oMC 3 (v1.00) methods by speedup factors of up to 1.6, 1.9 and 2.9, respectively. Moreover, tgMC 3 ++ supports more evolutionary models and gamma categories, which previous GPU-oriented methods fail to take into analysis.

Integrating remote sensing, geographic information system and modeling for estimating crop yield

NASA Astrophysics Data System (ADS)

Salazar, Luis Alonso

This thesis explores various aspects of the use of remote sensing, geographic information system and digital signal processing technologies for broad-scale estimation of crop yield in Kansas. Recent dry and drought years in the Great Plains have emphasized the need for new sources of timely, objective and quantitative information on crop conditions. Crop growth monitoring and yield estimation can provide important information for government agencies, commodity traders and producers in planning harvest, storage, transportation and marketing activities. The sooner this information is available the lower the economic risk translating into greater efficiency and increased return on investments. Weather data is normally used when crop yield is forecasted. Such information, to provide adequate detail for effective predictions, is typically feasible only on small research sites due to expensive and time-consuming collections. In order for crop assessment systems to be economical, more efficient methods for data collection and analysis are necessary. The purpose of this research is to use satellite data which provides 50 times more spatial information about the environment than the weather station network in a short amount of time at a relatively low cost. Specifically, we are going to use Advanced Very High Resolution Radiometer (AVHRR) based vegetation health (VH) indices as proxies for characterization of weather conditions.

Compressed-air energy-storage preliminary design and site-development program in an aquifer. Volume 9: Cost estimate and schedule

NASA Astrophysics Data System (ADS)

1982-12-01

The behavior and suitability of aquifers as compressed-air energy-storage sites is discussed. The engineering and construction schedule, facilities capital-cost estimate, and corresponding cash-flow requirements are given.

Measurements of aquifer-storage change and specific yield using gravity surveys

USGS Publications Warehouse

Pool, D.R.; Eychaner, J.H.

1995-01-01

Pinal Creek is an intermittent stream that drains a 200-square-mile alluvial basin in central Arizona. Large changes in water levels and aquifer storage occur in an alluvial aquifer near the stream in response to periodic recharge and ground-water withdrawals. Outflow components of the ground-water budget and hydraulic properties of the alluvium are well-defined by field measurements; however, data are insufficient to adequately describe recharge, aquifer-storage change, and specific-yield values. An investigation was begun to assess the utility of temporal-gravity surveys to directly measure aquifer-storage change and estimate values of specific yield.The temporal-gravity surveys measured changes in the differences in gravity between two reference stations on bedrock and six stations at wells; changes are caused by variations in aquifer storage. Specific yield was estimated by dividing storage change by water-level change. Four surveys were done between February 21, 1991, and March 31, 1993. Gravity increased as much as 158 microGal ± 1 to 6 microGal, and water levels rose as much as 58 feet. Average specific yield at wells ranged from 0.16 to 0.21, and variations in specific yield with depth correlate with lithologic variations. Results indicate that temporal-gravity surveys can be used to estimate aquifer-storage change and specific yield of water-table aquifers where significant variations in water levels occur. Direct measurement of aquifer-storage change can eliminate a major unknown from the ground-water budget of arid basins and improve residual estimates of recharge.

Two-stage energy storage equalization system for lithium-ion battery pack

NASA Astrophysics Data System (ADS)

Chen, W.; Yang, Z. X.; Dong, G. Q.; Li, Y. B.; He, Q. Y.

2017-11-01

How to raise the efficiency of energy storage and maximize storage capacity is a core problem in current energy storage management. For that, two-stage energy storage equalization system which contains two-stage equalization topology and control strategy based on a symmetric multi-winding transformer and DC-DC (direct current-direct current) converter is proposed with bidirectional active equalization theory, in order to realize the objectives of consistent lithium-ion battery packs voltages and cells voltages inside packs by using a method of the Range. Modeling analysis demonstrates that the voltage dispersion of lithium-ion battery packs and cells inside packs can be kept within 2 percent during charging and discharging. Equalization time was 0.5 ms, which shortened equalization time of 33.3 percent compared with DC-DC converter. Therefore, the proposed two-stage lithium-ion battery equalization system can achieve maximum storage capacity between lithium-ion battery packs and cells inside packs, meanwhile efficiency of energy storage is significantly improved.

Integration of cloud-based storage in BES III computing environment

NASA Astrophysics Data System (ADS)

Wang, L.; Hernandez, F.; Deng, Z.

2014-06-01

We present an on-going work that aims to evaluate the suitability of cloud-based storage as a supplement to the Lustre file system for storing experimental data for the BES III physics experiment and as a backend for storing files belonging to individual members of the collaboration. In particular, we discuss our findings regarding the support of cloud-based storage in the software stack of the experiment. We report on our development work that improves the support of CERN' s ROOT data analysis framework and allows efficient remote access to data through several cloud storage protocols. We also present our efforts providing the experiment with efficient command line tools for navigating and interacting with cloud storage-based data repositories both from interactive sessions and grid jobs.

Cavity-enhanced eigenmode and angular hybrid multiplexing in holographic data storage systems.

PubMed

Miller, Bo E; Takashima, Yuzuru

2016-12-26

Resonant optical cavities have been demonstrated to improve energy efficiencies in Holographic Data Storage Systems (HDSS). The orthogonal reference beams supported as cavity eigenmodes can provide another multiplexing degree of freedom to push storage densities toward the limit of 3D optical data storage. While keeping the increased energy efficiency of a cavity enhanced reference arm, image bearing holograms are multiplexed by orthogonal phase code multiplexing via Hermite-Gaussian eigenmodes in a Fe:LiNbO₃ medium with a 532 nm laser at two Bragg angles. We experimentally confirmed write rates are enhanced by an average factor of 1.1, and page crosstalk is about 2.5%. This hybrid multiplexing opens up a pathway to increase storage density while minimizing modification of current angular multiplexing HDSS.

Estimating the kinetic parameters of activated sludge storage using weighted non-linear least-squares and accelerating genetic algorithm.

PubMed

Fang, Fang; Ni, Bing-Jie; Yu, Han-Qing

2009-06-01

In this study, weighted non-linear least-squares analysis and accelerating genetic algorithm are integrated to estimate the kinetic parameters of substrate consumption and storage product formation of activated sludge. A storage product formation equation is developed and used to construct the objective function for the determination of its production kinetics. The weighted least-squares analysis is employed to calculate the differences in the storage product concentration between the model predictions and the experimental data as the sum of squared weighted errors. The kinetic parameters for the substrate consumption and the storage product formation are estimated to be the maximum heterotrophic growth rate of 0.121/h, the yield coefficient of 0.44 mg CODX/mg CODS (COD, chemical oxygen demand) and the substrate half saturation constant of 16.9 mg/L, respectively, by minimizing the objective function using a real-coding-based accelerating genetic algorithm. Also, the fraction of substrate electrons diverted to the storage product formation is estimated to be 0.43 mg CODSTO/mg CODS. The validity of our approach is confirmed by the results of independent tests and the kinetic parameter values reported in literature, suggesting that this approach could be useful to evaluate the product formation kinetics of mixed cultures like activated sludge. More importantly, as this integrated approach could estimate the kinetic parameters rapidly and accurately, it could be applied to other biological processes.

Estimates of consumptive use and ground-water return flow using water budgets in Palo Verde Valley, California

USGS Publications Warehouse

Owen-Joyce, Sandra J.; Kimsey, Steven L.

1987-01-01

Palo Verde Valley, California, is an agricultural area in the flood plain of the Colorado River where irrigation water is diverted from the river and groundwater is discharged to a network of drainage ditches and (or) the river. Consumptive use by vegetation and groundwater return flow were calculated using water budgets. Consumptive use by vegetation was 484,000 acre-ft in 1981, 453,600 acre-ft in 1982, 364,400 acre-ft in 1983, and 374,300 acre-ft in 1984. The consumptive-use estimates are most sensitive to two measured components of the water budget, the diversion at Palo Verde Dam and the discharge from drainage ditches to the river. Groundwater return flow was 31,700 acre-ft in 1981, 24,000 acre-ft in 1982, 2,500 acre-ft in 1983, and 7 ,900 acre-ft in 1984. The return-flow estimates are most sensitive to discharge from drainage ditches; various irrigation requirements and crop areas, particularly alfalfa; the diversion at Palo Verde Dam; and the estimate of consumptive use. During increasing flows in the river, the estimate of groundwater return flow is sensitive also to change in groundwater storage. Change in groundwater storage was estimated to be -5,700 acre-ft in 1981, -12,600 acre-ft in 1982, 5,200 acre-ft in 1983, and 11 ,600 acre-ft in 1984. Changes in storage can be a significant component in the water budget used to estimate groundwater return flow but is negligible in the water budget used to estimate consumptive use. Change in storage was 1 to 3% of annual consumptive use. Change in storage for the area drained by the river ranged from 7 to 96% of annual groundwater return flow during the 4 years studied. Consumptive use calculated as diversions minus return flows was consistently lower than consumptive use calculated in a water budget. Water-budget estimates of consumptive use account for variations in precipitation, tributary inflow, river stage, and groundwater storage. The calculations for diversions minus return flows do not account for these components, which can be large enough to affect the estimates of consumptive use. (Author 's abstract)

Evolution of Root Zone Storage after Land Use Change

NASA Astrophysics Data System (ADS)

Nijzink, R.; Hutton, C.; Capell, R.; Pechlivanidis, I.; Hrachowitz, M.; Savenije, H.

2015-12-01

It has been acknowledged for some time that a coupling exists between vegetation, climate and hydrological processes (e.g. Eagleson, 1982a, Rodriguez-Iturbe,2001 ). Recently, Gao et al.(2014) demonstrated that one of the core parameters of hydrological functioning, the catchment-scale root zone water storage capacity, can be estimated based on climate data alone. It was shown that ecosystems develop root zone storage capacities that allow vegetation to bridge droughts with return periods of about 20 years. As a consequence, assuming that the evaporative demand determines the root zone storage capacity, land use changes, such as deforestation, should have an effect on the development of this capacity . In this study it was tested to which extent deforestation affects root zone storage capacities. To do so, four different hydrological models were calibrated in a moving window approach after deforestation occurred. In this way, model based estimates of the storage capacity in time were obtained. This was compared with short term estimates of root zone storage capacities based on a climate based method similar to Gao et al.(2014). In addition, the equilibrium root zone storage capacity was determined with the total time series of an unaffected control catchment. Preliminary results indicate that models tend to adjust their storage capacity to the values found by the climate based method. This is strong evidence that the root zone storage is determined by the evaporative demand of vegetation. Besides, root zones storage capacities develop towards an equilibrium value where the ecosystem is in balance, further highlighting the evolving, time dynamic character of hydrological systems.

[Effects of deep plowing and mulch in fallow period on soil water and yield of wheat in dryland].

PubMed

Deng, Yan; Gao, Zhi-Qiang; Sun, Min; Zhao, Wei-Feng; Zhao, Hong-Mei; Li, Qing

2014-01-01

A field test was carried out in Qiujialing Village, Wenxi, Shanxi from 2009 to 2011 to study the soil water movement of 0-300 cm layer, yield formation and water use efficiency (WUE) of wheat with deep plowing and mulching the whole ground immediately (no mulch as control) 15 days and 45 days after harvest. The results indicated that deep plowing and mulch in fallow period could improve soil water storage of the 100-180 cm layer before sowing, the soil water storage efficiency in fallow period, and soil water storage from pre-wintering stage to booting stage. Compared with deep plowing 15 days after wheat harvest, deep plowing 45 days after wheat harvest did better in improving soil water storage and water use efficiency, as well as ear number and yield, which was more conducive in the year with more precipitation. Generally, deep plowing and mulching after raining during fallow period could benefit the soil water storage and conservation, thus would be helpful to improve wheat yield in dryland.

Development of Structural Energy Storage for Aeronautics Applications

NASA Technical Reports Server (NTRS)

Santiago-Dejesus, Diana; Loyselle, Patricia L.; Demattia, Brianne; Bednarcyk, Brett; Olson, Erik; Smith, Russell; Hare, David

2017-01-01

The National Aeronautics and Space Administration (NASA) has identified Multifunctional Structures for High Efficiency Lightweight Load-bearing Storage (M-SHELLS) as critical to development of hybrid gas-electric propulsion for commercial aeronautical transport in the N+3 timeframe. The established goals include reducing emissions by 80 and fuel consumption by 60 from todays state of the art. The advancement will enable technology for NASA Aeronautics Research Mission Directorates (ARMD) Strategic Thrust 3 to pioneer big leaps in efficiency and environmental performance for ultra-efficient commercial transports, as well as Strategic Thrust 4 to pioneer low-carbon propulsion technology in the transition to that scheme. The M-SHELLS concept addresses the hybrid gas-electric highest risk with its primary objective: to save structures energy storage system weight for future commercial hybrid electric propulsion aircraft by melding the load-carrying structure with energy storage in a single material. NASA's multifunctional approach also combines supercapacitor and battery chemistries in a synergistic energy storage arrangement in tandem with supporting good mechanical properties. The arrangement provides an advantageous combination of specific power, energy, and strength.

New insights into designing metallacarborane based room temperature hydrogen storage media.

PubMed

Bora, Pankaj Lochan; Singh, Abhishek K

2013-10-28

Metallacarboranes are promising towards realizing room temperature hydrogen storage media because of the presence of both transition metal and carbon atoms. In metallacarborane clusters, the transition metal adsorbs hydrogen molecules and carbon can link these clusters to form metal organic framework, which can serve as a complete storage medium. Using first principles density functional calculations, we chalk out the underlying principles of designing an efficient metallacarborane based hydrogen storage media. The storage capacity of hydrogen depends upon the number of available transition metal d-orbitals, number of carbons, and dopant atoms in the cluster. These factors control the amount of charge transfer from metal to the cluster, thereby affecting the number of adsorbed hydrogen molecules. This correlation between the charge transfer and storage capacity is general in nature, and can be applied to designing efficient hydrogen storage systems. Following this strategy, a search for the best metallacarborane was carried out in which Sc based monocarborane was found to be the most promising H2 sorbent material with a 9 wt.% of reversible storage at ambient pressure and temperature.

New insights into designing metallacarborane based room temperature hydrogen storage media

DOE Office of Scientific and Technical Information (OSTI.GOV)

Bora, Pankaj Lochan; Singh, Abhishek K.

Metallacarboranes are promising towards realizing room temperature hydrogen storage media because of the presence of both transition metal and carbon atoms. In metallacarborane clusters, the transition metal adsorbs hydrogen molecules and carbon can link these clusters to form metal organic framework, which can serve as a complete storage medium. Using first principles density functional calculations, we chalk out the underlying principles of designing an efficient metallacarborane based hydrogen storage media. The storage capacity of hydrogen depends upon the number of available transition metal d-orbitals, number of carbons, and dopant atoms in the cluster. These factors control the amount of chargemore » transfer from metal to the cluster, thereby affecting the number of adsorbed hydrogen molecules. This correlation between the charge transfer and storage capacity is general in nature, and can be applied to designing efficient hydrogen storage systems. Following this strategy, a search for the best metallacarborane was carried out in which Sc based monocarborane was found to be the most promising H{sub 2} sorbent material with a 9 wt.% of reversible storage at ambient pressure and temperature.« less

Comparative geomorphic analysis of surficial deposits at three central Appalachian watersheds: Implications for controls on sediment-transport efficiency

NASA Astrophysics Data System (ADS)

Taylor, Stephen B.; Steven Kite, J.

2006-08-01

Factors that control the routing and storage of sediments in the Appalachian region are poorly understood. This study involves a comparative geomorphic analysis of three watersheds underlain by sandstones and shales of the Acadian clastic wedge. These areas include the Fernow Experimental Forest, Tucker County, West Virginia; the North Fork basin, Pocahontas County, West Virginia; and the Little River basin, Augusta County, Virginia. GIS-based analyses of surficial map units allow first-order approximation of sediment-storage volumes in valley bottoms. Estimates of volumes are examined in tandem with morphometric analyses and the distribution of bedrock channels to make inferences regarding controls on sediment-transport efficiency in the central Appalachians. The Fernow and North Fork areas are characterized by V-shaped valleys with mixed reaches of alluvial-bedrock channels distributed throughout the drainage network. In contrast, the Little River valley is notably wider and gravelly alluvial fill is abundant. Comparator watershed parameters for the Fernow, North Fork and Little River areas include, respectively: (1) basin area = 15.2 km 2, 49.3 km 2, 41.5 km 2; (2) basin relief = 0.586 km, 0.533 km, 0.828 km; (3) drainage density = 4.2 km - 1 , 3.3 km - 1 , 4.7 km - 1 ; (4) ruggedness = 2.5, 1.7, 3.9; (5) Shreve magnitude = 139, 287, 380; (6) total valley-bottom area (km 2) = 0.76 km 2, 1.86 km 2, 3.09 km 2; (7) average hillslope gradients = 17.2°, 18.4°, 22.1°; (8) total debris-fan surface area = 0.113 km 2, 0.165 km 2, 0.486 km 2; and (9) debris-fan frequency = 2.0 km - 2 , 1.0 km - 2 , 2.8 km - 2 . The storage volumes in valley bottoms were estimated using map polygon areas and surface heights above channel grade. The Little River contains significantly higher sediment volumes in floodplain, terrace and fan storage compartments; total volumes of the valley bottoms are approximately twice that of the Fernow and North Fork areas combined. Unit storage volumes for the Fernow, North Fork and Little River are 5.2 × 10 4 m 3 km - 2 , 5.5 × 10 4 m 3 km - 2 and 1.6 × 10 5 m 3 km - 2 , respectively. A conceptual model postulates that valley-width morphometry and style of delivery from hillslopes are the primary factors controlling the efficiency of sediment transport. Steep, debris-flow-prone hillslopes at the Little River deliver high volumes of gravelly sediment at magnitudes greater than transport capacity of the channel. Patterns of stream power are complex, as low-order tributaries are under capacity and high-order tributaries over capacity with respect to sediment load. Aggraded alluvial fill insulates valley-floor bedrock from vertical erosion and valley widening dominates. Expansion of the valley width creates a positive response via increased storage capacity and lower unit stream power. Conversely, the Fernow and North Fork are characterized by diffusive mass movement on hillslopes with incremental bedload transport to higher-order tributaries. Rates of hillslope delivery are balanced by the rate of channel export. Mixed alluvial-bedrock reaches provide the optimal channel configuration for active incision of the valley floor. Low expansion of valley width promotes high unit stream power and processes of vertical erosion. The model implies that the Fernow and North Fork have been more effective at sediment transport during the Late Quaternary. Given similar climatic and tectonic settings, variation in bedrock lithofacies is likely the primary factor modulating the efficiency of sediment transport.

Riparian Vegetation, Sediment Dynamics and Hydrologic Change in the Minnesota River Basin

NASA Astrophysics Data System (ADS)

Batts, V. A.; Triplett, L.; Gran, K. B.; Lenhart, C. F.

2014-12-01

In the last three decades the Minnesota River Basin (MRB) has experienced increased precipitation and anthropogenic alteration to the drainage network, which contributes to higher flows and increased sediment loading. From field and laboratory approaches, this study investigates the implications of hydrologic change on the colonization of riparian vegetation on pointbars, and of vegetation loss on near-channel sediment storage within the lower Minnesota River. Field surveys consisted of vegetation surveys along pointbars, which were then related to flow records. Surveys revealed a dominance of woody seedlings over older established saplings, and high frequencies of species with alternative forms of propagation that tolerate high flows such as sandbar willow (Salix interior), and beggarticks (Bidens sp.). Surveys also showed in increase in elevation of plant establishment from measurements taken in 1979, resulting in higher area of exposed pointbar and easier mobilization of sediment. Geospatial analysis completed at each sampling location found decreased area of exposed pointbar in association with increases in pointbar vegetation between lower flow years and increased area of exposed pointbar in association with decreased pointbar vegetation between higher flow years. An experimental approach addresses implications of vegetation loss on pointbar sediment storage. In a 1.5m x 6m flume, we are conducting experiments to measure the efficiency of bar vegetation in trapping fine sediment as a function of stem density. Self-formed pointbars are vegetated at varying densities with Medicago sativa (alfalfa) sprouts to represent riparian woody saplings, then flooded with fine sediment-rich water to simulate summer flooding. Sediment deposited at each stem density is then measured to estimate efficiency. While results of these experiments are currently ongoing, we hypothesize that a threshold density exists at which trapping efficiency declines substantially. Preliminary results from this study demonstrate the biogeomorphic relationships between hydrologic regime, vegetation establishment, and sediment storage within the MRB. An understanding of these relationships will aid in development and implication of management actions necessary to address sediment related impairments in the MRB.

A Superconducting Magnet UCN Trap for Precise Neutron Lifetime Measurements.

PubMed

Picker, R; Altarev, I; Bröcker, J; Gutsmiedl, E; Hartmann, J; Müller, A; Paul, S; Schott, W; Trinks, U; Zimmer, O

2005-01-01

Finite-element methods along with Monte Carlo simulations were used to design a magnetic storage device for ultracold neutrons (UCN) to measure their lifetime. A setup was determined which should make it possible to confine UCN with negligible losses and detect the protons emerging from β-decay with high efficiency: stacked superconducting solenoids create the magnetic storage field, an electrostatic extraction field inside the storage volume assures high proton collection efficiency. Alongside with the optimization of the magnetic and electrostatic design, the properties of the trap were investigated through extensive Monte Carlo simulation.

Design of the storage location based on the ABC analyses

NASA Astrophysics Data System (ADS)

Jemelka, Milan; Chramcov, Bronislav; Kříž, Pavel

2016-06-01

The paper focuses on process efficiency and saving storage costs. Maintaining inventory through putaway strategy takes personnel time and costs money. The aim is to control inventory in the best way. The ABC classification based on Villefredo Pareto theory is used for a design of warehouse layout. New design of storage location reduces the distance of fork-lifters, total costs and it increases inventory process efficiency. The suggested solutions and evaluation of achieved results are described in detail. Proposed solutions were realized in real warehouse operation.

Carbon Storage in Urban Areas in the USA

NASA Astrophysics Data System (ADS)

Churkina, G.; Brown, D.; Keoleian, G.

2007-12-01

It is widely accepted that human settlements occupy a small proportion of the landmass and therefore play a relatively small role in the dynamics of the global carbon cycle. Most modeling studies focusing on the land carbon cycle use models of varying complexity to estimate carbon fluxes through forests, grasses, and croplands, but completely omit urban areas from their scope. Here, we estimate carbon storage in urban areas within the United States, defined to encompass a range of observed settlement densities, and its changes from 1950 to 2000. We show that this storage is not negligible and has been continuously increasing. We include natural- and human-related components of urban areas in our estimates. The natural component includes carbon storage in urban soil and vegetation. The human related component encompasses carbon stored long term in buildings, furniture, cars, and waste. The study suggests that urban areas should receive continued attention in efforts to accurately account for carbon uptake and storage in terrestrial systems.

MARC ES: a computer program for estimating medical information storage requirements.

PubMed

Konoske, P J; Dobbins, R W; Gauker, E D

1998-01-01

During combat, documentation of medical treatment information is critical for maintaining continuity of patient care. However, knowledge of prior status and treatment of patients is limited to the information noted on a paper field medical card. The Multi-technology Automated Reader Card (MARC), a smart card, has been identified as a potential storage mechanism for casualty medical information. Focusing on data capture and storage technology, this effort developed a Windows program, MARC ES, to estimate storage requirements for the MARC. The program calculates storage requirements for a variety of scenarios using medical documentation requirements, casualty rates, and casualty flows and provides the user with a tool to estimate the space required to store medical data at each echelon of care for selected operational theaters. The program can also be used to identify the point at which data must be uploaded from the MARC if size constraints are imposed. Furthermore, this model can be readily extended to other systems that store or transmit medical information.

Enhanced light use efficiency as a mechanism for forest carbon storage resilience following disturbance

NASA Astrophysics Data System (ADS)

Gough, C. M.; Hardiman, B. S.; Bohrer, G.; Maurer, K.; Nave, L. E.; Vogel, C. S.; Curtis, P.; University of Michigan Biological Station Forest Ecosystem STudy (FEST) Team

2011-12-01

Disturbances to forests such as those caused by herbivory, wind, pathogens, and age-related mortality may subtly alter canopy structure, with variable consequences for carbon (C) cycling. Forest C storage resilience following disturbance in which only a fraction of the canopy is defoliated may depend upon canopy structural shifts that compensate for lost leaf area by improving the efficiency of light-use by the altered canopy. In a forest at the University of Michigan Biological Station that is regionally representative of the northern Great Lakes, we initiated an experiment that examines forest C storage following subtle canopy disturbance. The Forest Accelerated Succession ExperimenT (FASET), in which >6,700 aspen and birch trees (~35 % LAI) were stem girdled within a 39 ha area, is investigating how C storage changes as Great Lakes forests broadly undergo a transition in which early successional canopy trees die and give way to an assemblage of later successional canopy dominants. The experiment employs a suite of paired C cycling measurements within separate treatment and control meteorological flux tower footprints. Forest carbon storage, quantified as annual net ecosystem production (NEP) and net primary production (NPP), was resilient to partial canopy defoliation, with rapid structural changes improving canopy light-use efficiency (LUE). Declining aspen and birch leaf area was offset by new foliar growth from later successional species already present in the canopy; however, the distribution of foliage within the canopy became more heterogeneous following disturbance as patchy aspen and birch mortality produced gaps and the vertical structure of the forest diversified. These canopy structural alterations prompted by small-scale patchy disturbance may have permitted deeper light penetration into the canopy, decreasing the fraction of absorbed photosynthetically active radiation (PAR) while increasing the efficiency in which absorbed light was used to drive canopy C uptake. The result was little change in forest C storage in the first several years following disturbance. We conclude that forest C storage resilience depends not only on replacement of lost leaf area, but also on shifts in forest structure that permit greater efficiency of light-use to drive C storage. These findings suggest that structural changes in the canopy should be considered in addition to trajectories of leaf area recovery when predicting the extent and duration of disturbance-related shifts in forest C storage.

A distributed, dynamic, parallel computational model: the role of noise in velocity storage

PubMed Central

Merfeld, Daniel M.

2012-01-01

Networks of neurons perform complex calculations using distributed, parallel computation, including dynamic “real-time” calculations required for motion control. The brain must combine sensory signals to estimate the motion of body parts using imperfect information from noisy neurons. Models and experiments suggest that the brain sometimes optimally minimizes the influence of noise, although it remains unclear when and precisely how neurons perform such optimal computations. To investigate, we created a model of velocity storage based on a relatively new technique–“particle filtering”–that is both distributed and parallel. It extends existing observer and Kalman filter models of vestibular processing by simulating the observer model many times in parallel with noise added. During simulation, the variance of the particles defining the estimator state is used to compute the particle filter gain. We applied our model to estimate one-dimensional angular velocity during yaw rotation, which yielded estimates for the velocity storage time constant, afferent noise, and perceptual noise that matched experimental data. We also found that the velocity storage time constant was Bayesian optimal by comparing the estimate of our particle filter with the estimate of the Kalman filter, which is optimal. The particle filter demonstrated a reduced velocity storage time constant when afferent noise increased, which mimics what is known about aminoglycoside ablation of semicircular canal hair cells. This model helps bridge the gap between parallel distributed neural computation and systems-level behavioral responses like the vestibuloocular response and perception. PMID:22514288

An objective frequency domain method for subsurface characterisation using Earth and atmospheric tides

NASA Astrophysics Data System (ADS)

Cuthbert, M. O.; Acworth, I. R.; Halloran, L. J. S.; Rau, G. C.; Bernadi, T. L.

2017-12-01

It has long been recognised that hydraulic properties can be derived from the response of piezometric heads to tidal loadings. However, there is a degree of subjectivity in existing graphical approaches most commonly used to calculate barometric efficiency leading to uncertainties in derived values of compressible storage. Here we demonstrate a novel approach to remove these uncertainties by objectively deriving the barometric efficiency from groundwater hydraulic head responses using a frequency domain method. We take advantage of the presence of worldwide and ubiquitous atmospheric tide fluctuations which occur at 2 cycles per day (cpd). First we use a Fourier transform to calculate the amplitudes of the 2 cpd signals from co-located atmospheric pressure and hydraulic head time series measurements. Next we show how the Earth tide response at the same frequency can be quantified and removed so that this effect does not interfere with the calculation of the barometric efficiency. Finally, the ratio of the amplitude of the response at 2 cpd of hydraulic head to atmospheric pressure is used to quantify the barometric efficiency. This new method allows an objective quantification using `passive' in situ monitoring rather than resorting to aquifer pumping or laboratory tests. The minimum data requirements are 15 days duration of 6-hourly hydraulic head and atmospheric pressure measurements, and modelled Earth tide records which are readily conducted using freely available software. The new approach allows for a rapid and cost-effective alternative to traditional methods of estimating aquifer compressible storage properties without the subjectivity of existing approaches, and will be of importance to improving the spatial coverage of subsurface characterisation for groundwater resource evaluation and land subsidence assessment.

Thermal analysis elements of liquefied gas storage tanks

NASA Astrophysics Data System (ADS)

Yanvarev, I. A.; Krupnikov, A. V.

2017-08-01

Tasks of solving energy and resource efficient usage problems, both for oil producing companies and for companies extracting and transporting natural gas, are associated with liquefied petroleum gas technology development. Improving the operation efficiency of liquefied products storages provides for conducting structural, functional, and appropriate thermal analysis of tank parks in the general case as complex dynamic thermal systems.

Solar micro-power system for self-powered wireless sensor nodes

NASA Astrophysics Data System (ADS)

He, Yongtai; Li, Yangqiu; Liu, Lihui; Wang, Lei

2008-10-01

In self-powered wireless sensor nodes, the efficiency for environmental energy harvesting, storage and management determines the lifetime and environmental adaptability of the sensor nodes. However, the method of improving output efficiency for traditional photovoltaic power generation is not suitable for a solar micro-power system due to the special requirements for its application. This paper presents a solar micro-power system designed for a solar self-powered wireless sensor node. The Maximum Power Point Tracking (MPPT) of solar cells and energy storage are realized by the hybrid energy storage structure and "window" control. Meanwhile, the mathematical model of energy harvesting, storing and management is formulated. In the novel system, the output conversion efficiency of solar cells is 12%.

Peak power reduction and energy efficiency improvement with the superconducting flywheel energy storage in electric railway system

NASA Astrophysics Data System (ADS)

Lee, Hansang; Jung, Seungmin; Cho, Yoonsung; Yoon, Donghee; Jang, Gilsoo

2013-11-01

This paper proposes an application of the 100 kWh superconducting flywheel energy storage systems to reduce the peak power of the electric railway system. The electric railway systems have high-power characteristics and large amount of regenerative energy during vehicles’ braking. The high-power characteristic makes operating cost high as the system should guarantee the secure capacity of electrical equipment and the low utilization rate of regenerative energy limits the significant energy efficiency improvement. In this paper, it had been proved that the peak power reduction and energy efficiency improvement can be achieved by using 100 kWh superconducting flywheel energy storage systems with the optimally controlled charging or discharging operations. Also, economic benefits had been assessed.

Structural, petrophysical and geomechanical characterization of the Becancour CO2 storage pilot site (Quebec, Canada)

NASA Astrophysics Data System (ADS)

Konstantinovskaya, E.; Malo, M.; Claprood, M.; Tran-Ngoc, T. D.; Gloaguen, E.; Lefebvre, R.

2012-04-01

The Paleozoic sedimentary succession of the St. Lawrence Platform was characterized to estimate the CO2 storage capacity, the caprock integrity and the fracture/fault stability at the Becancour pilot site. Results are based on the structural interpretation of 25 seismic lines and analysis of 11 well logs and petrophysical data. The three potential storage units of Potsdam, Beekmantown and Trenton saline aquifers are overlain by a multiple caprock system of Utica shales and Lorraine siltstones. The NE-SW regional normal faults dipping to the SE affect the subhorizontal sedimentary succession. The Covey Hill (Lower Potsdam) was found to be the only unit with significant CO2 sequestration potential, since these coarse-grained poorly-sorted fluvial-deltaic quartz-feldspar sandstones are characterized by the highest porosity, matrix permeability and net pay thickness and have the lowest static Young modulus, Poisson's ratio and compressive strength relative to other units. The Covey Hill is located at depths of 1145-1259 m, thus injected CO2 would be in supercritical state according to observed salinity, temperature and fluid pressure. The calcareous Utica shale of the regional seal is more brittle and has higher Young modulus and lower Poisson's ratio than the overlying Lorraine shale. The 3D geological model is kriged using the tops of the geological formations recorded at wells and picked travel times as external drift. The computed CO2 storage capacity in the Covey Hill sandstones is estimated by the volumetric and compressibility methods as 0.22 tons/km2 with storage efficiency factor E 2.4% and 0.09 tons/km2 with E 1%, respectively. A first set of numerical radial simulations of CO2 injection into the Covey Hill were carried out with TOUGH2/ECO2N. A geomechanical analysis of the St. Lawrence Platform sedimentary basin provides the maximum sustainable fluid pressures for CO2 injection that will not induce tensile fracturing and shear reactivation along pre-existing fractures and faults in the caprock. The regional stresses/pressure gradients estimated for the Paleozoic sedimentary basin (depths < 4 km) indicate a strike-slip stress regime. The average maximum horizontal stress orientation (SHmax) is estimated N62.8°E±4.0° in the Becancour-Notre Dame area. The high-angle NE-SW Yamaska normal fault is oriented at 16.7° to the SHmax orientation in the Becancour site. The slip tendency along the fault in this area is estimated to be 0.47 based on the stress magnitude and rock strength evaluations for the borehole breakout intervals in local wells. The regional pore pressure-stress coupling ratio under assumed parameters is about 0.5-0.65 and may contribute to reduce the risk of shear reactivation of faults and fractures. The maximum sustainable fluid pressure that would not cause opening of vertical tensile fractures during CO2 operations is about 18.5-20 MPa at a depth of 1 km.

Energy Storage on the Grid and the Short-term Variability of Wind

NASA Astrophysics Data System (ADS)

Hittinger, Eric Stephen

Wind generation presents variability on every time scale, which must be accommodated by the electric grid. Limited quantities of wind power can be successfully integrated by the current generation and demand-side response mix but, as deployment of variable resources increases, the resulting variability becomes increasingly difficult and costly to mitigate. In Chapter 2, we model a co-located power generation/energy storage block composed of wind generation, a gas turbine, and fast-ramping energy storage. A scenario analysis identifies system configurations that can generate power with 30% of energy from wind, a variability of less than 0.5% of the desired power level, and an average cost around $70/MWh. While energy storage technologies have existed for decades, fast-ramping grid-level storage is still an immature industry and is experiencing relatively rapid improvements in performance and cost across a variety of technologies. Decreased capital cost, increased power capability, and increased efficiency all would improve the value of an energy storage technology and each has cost implications that vary by application, but there has not yet been an investigation of the marginal rate of technical substitution between storage properties. The analysis in chapter 3 uses engineering-economic models of four emerging fast-ramping energy storage technologies to determine which storage properties have the greatest effect on cost-of-service. We find that capital cost of storage is consistently important, and identify applications for which power/energy limitations are important. In some systems with a large amount of wind power, the costs of wind integration have become significant and market rules have been slowly changing in order to internalize or control the variability of wind generation. Chapter 4 examines several potential market strategies for mitigating the effects of wind variability and estimate the effect that each strategy would have on the operation and profitability of wind farms. We find that market scenarios using existing price signals to motivate wind to reduce variability allow wind generators to participate in variability reduction when the market conditions are favorable, and can reduce short-term (30-minute) fluctuations while having little effect on wind farm revenue.

Quantifying the role of urban forests in removing atmospheric carbon dioxide

Treesearch

Rowan A. Rowntree; David J. Nowak

1991-01-01

Urban land in the United States currently occupies about 69 million acres with an estimated average crown cover of 28% and an estimated tree biomass of about 27 tons/acre. This structure suggests that the current total urban forest carbon storage in the United States is approximately 800 million tons with an estimated annual net carbon storage of around 6.5 million...

National assessment of geologic carbon dioxide storage resources: results

USGS Publications Warehouse

,

2013-01-01

In 2012, the U.S. Geological Survey (USGS) completed an assessment of the technically accessible storage resources (TASR) for carbon dioxide (CO2) in geologic formations underlying the onshore and State waters area of the United States. The formations assessed are at least 3,000 feet (914 meters) below the ground surface. The TASR is an estimate of the CO2 storage resource that may be available for CO2 injection and storage that is based on present-day geologic and hydrologic knowledge of the subsurface and current engineering practices. Individual storage assessment units (SAUs) for 36 basins were defined on the basis of geologic and hydrologic characteristics outlined in the assessment methodology of Brennan and others (2010, USGS Open-File Report 2010–1127) and the subsequent methodology modification and implementation documentation of Blondes, Brennan, and others (2013, USGS Open-File Report 2013–1055). The mean national TASR is approximately 3,000 metric gigatons (Gt). The estimate of the TASR includes buoyant trapping storage resources (BSR), where CO2 can be trapped in structural or stratigraphic closures, and residual trapping storage resources, where CO2 can be held in place by capillary pore pressures in areas outside of buoyant traps. The mean total national BSR is 44 Gt. The residual storage resource consists of three injectivity classes based on reservoir permeability: residual trapping class 1 storage resource (R1SR) represents storage in rocks with permeability greater than 1 darcy (D); residual trapping class 2 storage resource (R2SR) represents storage in rocks with moderate permeability, defined as permeability between 1 millidarcy (mD) and 1 D; and residual trapping class 3 storage resource (R3SR) represents storage in rocks with low permeability, defined as permeability less than 1 mD. The mean national storage resources for rocks in residual trapping classes 1, 2, and 3 are 140 Gt, 2,700 Gt, and 130 Gt, respectively. The known recovery replacement storage resource (KRRSR) is a conservative estimate that represents only the amount of CO2 at subsurface conditions that could replace the volume of known hydrocarbon production. The mean national KRRSR, determined from production volumes rather than the geologic model of buoyant and residual traps that make up TASR, is 13 Gt. The estimated storage resources are dominated by residual trapping class 2, which accounts for 89 percent of the total resources. The Coastal Plains Region of the United States contains the largest storage resource of any region. Within the Coastal Plains Region, the resources from the U.S. Gulf Coast area represent 59 percent of the national CO2 storage capacity.

Silicon Nanowire/Polymer Hybrid Solar Cell-Supercapacitor: A Self-Charging Power Unit with a Total Efficiency of 10.5.

PubMed

Liu, Ruiyuan; Wang, Jie; Sun, Teng; Wang, Mingjun; Wu, Changsheng; Zou, Haiyang; Song, Tao; Zhang, Xiaohong; Lee, Shuit-Tong; Wang, Zhong Lin; Sun, Baoquan

2017-07-12

An integrated self-charging power unit, combining a hybrid silicon nanowire/polymer heterojunction solar cell with a polypyrrole-based supercapacitor, has been demonstrated to simultaneously harvest solar energy and store it. By efficiency enhancement of the hybrid nanowire solar cells and a dual-functional titanium film serving as conjunct electrode of the solar cell and supercapacitor, the integrated system is able to yield a total photoelectric conversion to storage efficiency of 10.5%, which is the record value in all the integrated solar energy conversion and storage system. This system may not only serve as a buffer that diminishes the solar power fluctuations from light intensity, but also pave its way toward cost-effective high efficiency self-charging power unit. Finally, an integrated device based on ultrathin Si substrate is demonstrated to expand its feasibility and potential application in flexible energy conversion and storage devices.

Total water storage dynamics derived from tree-ring records and terrestrial gravity observations

NASA Astrophysics Data System (ADS)

Creutzfeldt, Benjamin; Heinrich, Ingo; Merz, Bruno

2015-10-01

For both societal and ecological reasons, it is important to understand past and future subsurface water dynamics but estimating subsurface water storage is notoriously difficult. In this pilot study, we suggest the reconstruction of subsurface water dynamics by a multi-disciplinary approach combining hydrology, dendrochronology and geodesy. In a first step, nine complete years of high-precision gravimeter observations are used to estimate water storage changes in the subsurface at the Geodetic Observatory Wettzell in the Bavarian Forest, Germany. The record is extended to 63 years by calibrating a hydrological model against the 9 years of gravimeter observations. The relationship between tree-ring growth and water storage changes is evaluated as well as that between tree-ring growth and supplementary hydro-meteorological data. Results suggest that tree-ring growth is influenced primarily by subsurface water storage. Other variables related to the overall moisture status (e.g., Standardized Precipitation Index, Palmer Drought Severity Index, streamflow) are also strongly correlated with tree-ring width. While these indices are all indicators of water stored in the landscape, water storage changes of the subsurface estimated by depth-integral measurements give us the unique opportunity to directly reconstruct subsurface water storage dynamics from records of tree-ring width. Such long reconstructions will improve our knowledge of past water storage variations and our ability to predict future developments. Finally, knowing the relationship between subsurface storage dynamics and tree-ring growth improves the understanding of the different signal components contained in tree-ring chronologies.

Global root zone storage capacity from satellite-based evaporation data

NASA Astrophysics Data System (ADS)

Wang-Erlandsson, Lan; Bastiaanssen, Wim; Gao, Hongkai; Jägermeyr, Jonas; Senay, Gabriel; van Dijk, Albert; Guerschman, Juan; Keys, Patrick; Gordon, Line; Savenije, Hubert

2016-04-01

We present an "earth observation-based" method for estimating root zone storage capacity - a critical, yet uncertain parameter in hydrological and land surface modelling. By assuming that vegetation optimises its root zone storage capacity to bridge critical dry periods, we were able to use state-of-the-art satellite-based evaporation data computed with independent energy balance equations to derive gridded root zone storage capacity at global scale. This approach does not require soil or vegetation information, is model independent, and is in principle scale-independent. In contrast to traditional look-up table approaches, our method captures the variability in root zone storage capacity within land cover type, including in rainforests where direct measurements of root depth otherwise are scarce. Implementing the estimated root zone storage capacity in the global hydrological model STEAM improved evaporation simulation overall, and in particular during the least evaporating months in sub-humid to humid regions with moderate to high seasonality. We find that evergreen forests are able to create a large storage to buffer for extreme droughts (with a return period of up to 60 years), in contrast to short vegetation and crops (which seem to adapt to a drought return period of about 2 years). The presented method to estimate root zone storage capacity eliminates the need for soils and rooting depth information, which could be a game-changer in global land surface modelling.

Improved water balance component estimates through joint assimilation of GRACE water storage and SMOS soil moisture retrievals

NASA Astrophysics Data System (ADS)

Tian, Siyuan; Tregoning, Paul; Renzullo, Luigi J.; van Dijk, Albert I. J. M.; Walker, Jeffrey P.; Pauwels, Valentijn R. N.; Allgeyer, Sébastien

2017-03-01

The accuracy of global water balance estimates is limited by the lack of observations at large scale and the uncertainties of model simulations. Global retrievals of terrestrial water storage (TWS) change and soil moisture (SM) from satellites provide an opportunity to improve model estimates through data assimilation. However, combining these two data sets is challenging due to the disparity in temporal and spatial resolution at both vertical and horizontal scale. For the first time, TWS observations from the Gravity Recovery and Climate Experiment (GRACE) and near-surface SM observations from the Soil Moisture and Ocean Salinity (SMOS) were jointly assimilated into a water balance model using the Ensemble Kalman Smoother from January 2010 to December 2013 for the Australian continent. The performance of joint assimilation was assessed against open-loop model simulations and the assimilation of either GRACE TWS anomalies or SMOS SM alone. The SMOS-only assimilation improved SM estimates but reduced the accuracy of groundwater and TWS estimates. The GRACE-only assimilation improved groundwater estimates but did not always produce accurate estimates of SM. The joint assimilation typically led to more accurate water storage profile estimates with improved surface SM, root-zone SM, and groundwater estimates against in situ observations. The assimilation successfully downscaled GRACE-derived integrated water storage horizontally and vertically into individual water stores at the same spatial scale as the model and SMOS, and partitioned monthly averaged TWS into daily estimates. These results demonstrate that satellite TWS and SM measurements can be jointly assimilated to produce improved water balance component estimates.

Space shuttle propulsion parameter estimation using optional estimation techniques

NASA Technical Reports Server (NTRS)

1983-01-01

A regression analyses on tabular aerodynamic data provided. A representative aerodynamic model for coefficient estimation. It also reduced the storage requirements for the "normal' model used to check out the estimation algorithms. The results of the regression analyses are presented. The computer routines for the filter portion of the estimation algorithm and the :"bringing-up' of the SRB predictive program on the computer was developed. For the filter program, approximately 54 routines were developed. The routines were highly subsegmented to facilitate overlaying program segments within the partitioned storage space on the computer.

NREL Screens Universities for Solar and Battery Storage Potential

DOE Office of Scientific and Technical Information (OSTI.GOV)

In support of the U.S. Department of Energy's SunShot initiative, NREL provided solar photovoltaic (PV) screenings in 2016 for eight universities seeking to go solar. NREL conducted an initial technoeconomic assessment of PV and storage feasibility at the selected universities using the REopt model, an energy planning platform that can be used to evaluate RE options, estimate costs, and suggest a mix of RE technologies to meet defined assumptions and constraints. NREL provided each university with customized results, including the cost-effectiveness of PV and storage, recommended system size, estimated capital cost to implement the technology, and estimated life cycle costmore » savings.« less

The geospatial and economic viability of CO 2 storage in hydrocarbon depleted fractured shale formations

DOE PAGES

Bielicki, Jeffrey M.; Langenfeld, Julie K.; Tao, Zhiyuan; ...

2018-05-26

Hydrocarbon depleted fractured shale (HDFS) formations could be attractive for geologic carbon dioxide (CO 2) storage. Shale formations may be able to leverage existing infrastructure, have larger capacities, and be more secure than saline aquifers. We compared regional storage capacities and integrated CO 2 capture, transport, and storage systems that use HDFS with those that use saline aquifers in a region of the United States with extensive shale development that overlies prospective saline aquifers. We estimated HDFS storage capacities with a production-based method and costs by adapting methods developed for saline aquifers and found that HDFS formations in this regionmore » might be able to store with less cost an estimated ~14× more CO 2 on average than saline aquifers at the same location. The potential for smaller Areas of Review and less investment in infrastructure accounted for up to 84% of the difference in estimated storage costs. We implemented an engineering-economic geospatial optimization model to determine and compare the viability of storage capacity for these two storage resources. Across the state-specific and regional scenarios we investigated, our results for this region suggest that integrated CCS systems using HDFS could be more centralized, require less pipelines, prioritize different routes for trunklines, and be 6.4–6.8% ($5-10/tCO 2) cheaper than systems using saline aquifers. In conclusion, overall, CO 2 storage in HDFS could be technically and economically attractive and may lower barriers to large scale CO 2 storage if they can be permitted.« less

The geospatial and economic viability of CO 2 storage in hydrocarbon depleted fractured shale formations

DOE Office of Scientific and Technical Information (OSTI.GOV)

Bielicki, Jeffrey M.; Langenfeld, Julie K.; Tao, Zhiyuan

Hydrocarbon depleted fractured shale (HDFS) formations could be attractive for geologic carbon dioxide (CO 2) storage. Shale formations may be able to leverage existing infrastructure, have larger capacities, and be more secure than saline aquifers. We compared regional storage capacities and integrated CO 2 capture, transport, and storage systems that use HDFS with those that use saline aquifers in a region of the United States with extensive shale development that overlies prospective saline aquifers. We estimated HDFS storage capacities with a production-based method and costs by adapting methods developed for saline aquifers and found that HDFS formations in this regionmore » might be able to store with less cost an estimated ~14× more CO 2 on average than saline aquifers at the same location. The potential for smaller Areas of Review and less investment in infrastructure accounted for up to 84% of the difference in estimated storage costs. We implemented an engineering-economic geospatial optimization model to determine and compare the viability of storage capacity for these two storage resources. Across the state-specific and regional scenarios we investigated, our results for this region suggest that integrated CCS systems using HDFS could be more centralized, require less pipelines, prioritize different routes for trunklines, and be 6.4–6.8% ($5-10/tCO 2) cheaper than systems using saline aquifers. In conclusion, overall, CO 2 storage in HDFS could be technically and economically attractive and may lower barriers to large scale CO 2 storage if they can be permitted.« less

Carbon storage in China's terrestrial ecosystems: A synthesis.

PubMed

Xu, Li; Yu, Guirui; He, Nianpeng; Wang, Qiufeng; Gao, Yang; Wen, Ding; Li, Shenggong; Niu, Shuli; Ge, Jianping

2018-02-12

It is important to accurately estimate terrestrial ecosystem carbon (C) storage. However, the spatial patterns of C storage and the driving factors remain unclear, owing to lack of data. Here, we collected data from literature published between 2004 and 2014 on C storage in China's terrestrial ecosystems, to explore variation in C storage across different ecosystems and evaluate factors that influence them. We estimated that total C storage was 99.15 ± 8.71 PgC, with 14.60 ± 3.24 PgC in vegetation C (Veg-C) and 84.55 ± 8.09 PgC in soil organic C (SOC) storage. Furthermore, C storage in forest, grassland, wetland, shrub, and cropland ecosystems (excluding vegetation) was 34.08 ± 5.43, 25.69 ± 4.71, 3.62 ± 0.80, 7.42 ± 1.92, and 15.17 ± 2.20 PgC, respectively. In addition to soil nutrients and texture, climate was the main factor regulating the spatial patterns of C storage. Climate influenced the spatial patterns of Veg-C and SOC density via different approaches, Veg-C was mainly positively influenced by mean annual precipitation (MAP), whereas SOC was negatively dependent on mean annual temperature (MAT). This systematic estimate of C storage in China provides new insights about how climate constrains C sequestration, demonstrating the contrasting effects of MAP and MAT on Veg-C and SOC; thus, these parameters should be incorporated into future land management and C sequestration strategies.

Control of storage-protein synthesis during seed development in pea (Pisum sativum L.).

PubMed Central

Gatehouse, J A; Evans, I M; Bown, D; Croy, R R; Boulter, D

1982-01-01

The tissue-specific syntheses of seed storage proteins in the cotyledons of developing pea (Pisum sativum L.) seeds have been demonstrated by estimates of their qualitative and quantitative accumulation by sodium dodecyl sulphate/polyacrylamide-gel electrophoresis and rocket immunoelectrophoresis respectively. Vicilin-fraction proteins initially accumulated faster than legumin, but whereas legumin was accumulated throughout development, different components of the vicilin fraction had their predominant periods of synthesis at different stages of development. The translation products in vitro of polysomes isolated from cotyledons at different stages of development reflected the synthesis in vivo of storage-protein polypeptides at corresponding times. The levels of storage-protein mRNA species during development were estimated by 'Northern' hybridization using cloned complementary-DNA probes. This technique showed that the levels of legumin and vicilin (47000-Mr precursors) mRNA species increased and decreased in agreement with estimated rates of synthesis of the respective polypeptides. The relative amounts of these messages, estimated by kinetic hybridization were also consistent. Legumin mRNA was present in leaf poly(A)+ RNA at less than one-thousandth of the level in cotyledon poly(A)+ (polyadenylated) RNA, demonstrating tissue-specific expression. Evidence is presented that storage-protein mRNA species are relatively long-lived, and it is suggested that storage-protein synthesis is regulated primarily at the transcriptional level. Images Fig. 2. Fig. 3. PMID:6897609

Quantifying the water storage volume of major aquifers in the US

NASA Astrophysics Data System (ADS)

Jame, S. A.; Bowling, L. C.

2017-12-01

Groundwater is one of our most valuable natural resources which affects not only the food and energy nexus, but ecosystem and human health, through the availability of drinking water. Quantification of current groundwater storage is not only required to better understand groundwater flow and its role in the hydrologic cycle, but also sustainable use. In this study, a new high resolution map (5' minutes) of groundwater properties is created for US major aquifers to provide an estimate of total groundwater storage. The estimation was done using information on the spatial extent of the principal aquifers of the US from the USGS Groundwater Atlas, the average porosity of different hydrolithologic groups and the current saturated thickness of each aquifer. Saturated thickness varies within aquifers, and has been calculated by superimposing current water-table contour maps over the base aquifer altitude provided by USGS. The average saturated thickness has been computed by interpolating available data on saturated thickness for an aquifer using the kriging method. Total storage of aquifers in each cell was then calculated by multiplying the spatial extent, porosity, and thickness of the saturated layer. The resulting aquifer storage estimates was compared with current groundwater withdrawal rates to produce an estimate of how many years' worth of water are stored in the aquifers. The resulting storage map will serve as a national dataset for stakeholders to make decisions for sustainable use of groundwater.

Monitoring groundwater storage changes in the highly dynamic Bengal Basin: validation of GRACE measurements

NASA Astrophysics Data System (ADS)

Shamsudduha, M.; Taylor, R. G.; Longuevergne, L.

2011-12-01

Monitoring of spatio-temporal changes in terrestrial water storage (ΔTWS) provides valuable information regarding the basin-scale dynamics of hydrological systems. Recent satellite measurements of the ΔTWS under the Gravity Recovery and Climate Experiment (GRACE) enable the derivation of groundwater storage changes (ΔGWS) where in situ data are limited. In the well monitored and highly-dynamic Bengal Basin of Bangladesh, we test the ability of GRACE measurements to trace the seasonality and trend in groundwater storage associated with intensive groundwater abstraction for dry-season irrigation and wet-season (monsoonal) recharge. Two different GRACE products (CSR and GRGS) and data processing methods (gridded and spherical harmonics) are also compared. Results show that GRACE derived estimates of recent (2003 to 2007) ΔGWS correlate well (r=0.77 to 0.93, p-value <0.0001) with borehole-derived estimates from a network of 236 monitoring stations in Bangladesh. The highest correlation (r=0.93, p-value <0.0001) and lowest root mean square error (<4 cm) are realized using a spherical harmonic product of CSR for these estimates. ΔGWS accounts for 44% of the total variation in ΔTWS in the Bengal Basin. Changes in surface water storage (ΔSWS) estimated from a network of 298 river gauging stations and soil moisture storage (ΔSMS) derived from Land Surface Models explain 22% and 33% of ΔTWS respectively. Groundwater depletion estimated from borehole hydrographs (-0.52±0.30 km3/yr) is within the range of satellite-derived estimates (-0.44 to -2.04 km3/yr) that result from uncertainty associated with ΔSMS (CLM, NOAH, VIC) and GRACE data processing techniques. Recent (2003 to 2007) estimates of groundwater depletion are substantially greater than the long-term (1985 to 2007) mean (-0.21±0.03 km3/yr) and are explained primarily by substantial increases in groundwater abstraction for the dry-season irrigation and drinking water supplies over the last two decades.

Non-invasive prediction of bloodstain age using the principal component and a back propagation artificial neural network

NASA Astrophysics Data System (ADS)

Sun, Huimin; Meng, Yaoyong; Zhang, Pingli; Li, Yajing; Li, Nan; Li, Caiyun; Guo, Zhiyou

2017-09-01

The age determination of bloodstains is an important and immediate challenge for forensic science. No reliable methods are currently available for estimating the age of bloodstains. Here we report a method for determining the age of bloodstains at different storage temperatures. Bloodstains were stored at 37 °C, 25 °C, 4 °C, and  -20 °C for 80 d. Bloodstains were measured using Raman spectroscopy at various time points. The principal component and a back propagation artificial neural network model were then established for estimating the age of the bloodstains. The results were ideal; the square of correlation coefficient was up to 0.99 (R 2  >  0.99) and the root mean square error of the prediction at lowest reached 55.9829 h. This method is real-time, non-invasive, non-destructive and highly efficiency. It may well prove that Raman spectroscopy is a promising tool for the estimation of the age of bloodstains.

Parametric Grid Information in the DOE Knowledge Base: Data Preparation, Storage, and Access

DOE Office of Scientific and Technical Information (OSTI.GOV)

HIPP,JAMES R.; MOORE,SUSAN G.; MYERS,STEPHEN C.

The parametric grid capability of the Knowledge Base provides an efficient, robust way to store and access interpolatable information which is needed to monitor the Comprehensive Nuclear Test Ban Treaty. To meet both the accuracy and performance requirements of operational monitoring systems, we use a new approach which combines the error estimation of kriging with the speed and robustness of Natural Neighbor Interpolation (NNI). The method involves three basic steps: data preparation (DP), data storage (DS), and data access (DA). The goal of data preparation is to process a set of raw data points to produce a sufficient basis formore » accurate NNI of value and error estimates in the Data Access step. This basis includes a set of nodes and their connectedness, collectively known as a tessellation, and the corresponding values and errors that map to each node, which we call surfaces. In many cases, the raw data point distribution is not sufficiently dense to guarantee accurate error estimates from the NNI, so the original data set must be densified using a newly developed interpolation technique known as Modified Bayesian Kriging. Once appropriate kriging parameters have been determined by variogram analysis, the optimum basis for NNI is determined in a process they call mesh refinement, which involves iterative kriging, new node insertion, and Delauny triangle smoothing. The process terminates when an NNI basis has been calculated which will fir the kriged values within a specified tolerance. In the data storage step, the tessellations and surfaces are stored in the Knowledge Base, currently in a binary flatfile format but perhaps in the future in a spatially-indexed database. Finally, in the data access step, a client application makes a request for an interpolated value, which triggers a data fetch from the Knowledge Base through the libKBI interface, a walking triangle search for the containing triangle, and finally the NNI interpolation.« less

Development of a concentrating solar power system using fluidized-bed technology for thermal energy conversion and solid particles for thermal energy storage

DOE PAGES

Ma, Z.; Mehos, M.; Glatzmaier, G.; ...

2015-05-01

Concentrating solar power (CSP) is an effective way to convert solar energy into electricity with an economic energy-storage capability for grid-scale, dispatchable renewable power generation. However, CSP plants need to reduce costs to be competitive with other power generation methods. Two ways to reduce CSP cost are to increase solar-to-electric efficiency by supporting a high-efficiency power conversion system, and to use low-cost materials in the system. The current nitrate-based molten-salt systems have limited potential for cost reduction and improved power-conversion efficiency with high operating temperatures. Even with significant improvements in operating performance, these systems face challenges in satisfying the costmore » and performance targets. This paper introduces a novel CSP system with high-temperature capability that can be integrated into a high-efficiency CSP plant and that meets the low-cost, high-performance CSP targets. Unlike a conventional salt-based CSP plant, this design uses gas/solid, two-phase flow as the heat-transfer fluid (HTF); separated solid particles as storage media; and stable, inexpensive materials for the high-temperature receiver and energy storage containment. We highlight the economic and performance benefits of this innovative CSP system design, which has thermal energy storage capability for base-load power generation.« less

Exploring storage and runoff generation processes for urban flooding through a physically based watershed model

NASA Astrophysics Data System (ADS)

Smith, B. K.; Smith, J. A.; Baeck, M. L.; Miller, A. J.

2015-03-01

A physically based model of the 14 km2 Dead Run watershed in Baltimore County, MD was created to test the impacts of detention basin storage and soil storage on the hydrologic response of a small urban watershed during flood events. The Dead Run model was created using the Gridded Surface Subsurface Hydrologic Analysis (GSSHA) algorithms and validated using U.S. Geological Survey stream gaging observations for the Dead Run watershed and 5 subbasins over the largest 21 warm season flood events during 2008-2012. Removal of the model detention basins resulted in a median peak discharge increase of 11% and a detention efficiency of 0.5, which was defined as the percent decrease in peak discharge divided by percent detention controlled area. Detention efficiencies generally decreased with increasing basin size. We tested the efficiency of detention basin networks by focusing on the "drainage network order," akin to the stream order but including storm drains, streams, and culverts. The detention efficiency increased dramatically between first-order detention and second-order detention but was similar for second and third-order detention scenarios. Removal of the soil compacted layer, a common feature in urban soils, resulted in a 7% decrease in flood peak discharges. This decrease was statistically similar to the flood peak decrease caused by existing detention. Current soil storage within the Dead Run watershed decreased flood peak discharges by a median of 60%. Numerical experiment results suggested that detention basin storage and increased soil storage have the potential to substantially decrease flood peak discharges.

A privacy-preserving solution for compressed storage and selective retrieval of genomic data.

PubMed

Huang, Zhicong; Ayday, Erman; Lin, Huang; Aiyar, Raeka S; Molyneaux, Adam; Xu, Zhenyu; Fellay, Jacques; Steinmetz, Lars M; Hubaux, Jean-Pierre

2016-12-01

In clinical genomics, the continuous evolution of bioinformatic algorithms and sequencing platforms makes it beneficial to store patients' complete aligned genomic data in addition to variant calls relative to a reference sequence. Due to the large size of human genome sequence data files (varying from 30 GB to 200 GB depending on coverage), two major challenges facing genomics laboratories are the costs of storage and the efficiency of the initial data processing. In addition, privacy of genomic data is becoming an increasingly serious concern, yet no standard data storage solutions exist that enable compression, encryption, and selective retrieval. Here we present a privacy-preserving solution named SECRAM (Selective retrieval on Encrypted and Compressed Reference-oriented Alignment Map) for the secure storage of compressed aligned genomic data. Our solution enables selective retrieval of encrypted data and improves the efficiency of downstream analysis (e.g., variant calling). Compared with BAM, the de facto standard for storing aligned genomic data, SECRAM uses 18% less storage. Compared with CRAM, one of the most compressed nonencrypted formats (using 34% less storage than BAM), SECRAM maintains efficient compression and downstream data processing, while allowing for unprecedented levels of security in genomic data storage. Compared with previous work, the distinguishing features of SECRAM are that (1) it is position-based instead of read-based, and (2) it allows random querying of a subregion from a BAM-like file in an encrypted form. Our method thus offers a space-saving, privacy-preserving, and effective solution for the storage of clinical genomic data. © 2016 Huang et al.; Published by Cold Spring Harbor Laboratory Press.

A privacy-preserving solution for compressed storage and selective retrieval of genomic data

PubMed Central

Huang, Zhicong; Ayday, Erman; Lin, Huang; Aiyar, Raeka S.; Molyneaux, Adam; Xu, Zhenyu; Hubaux, Jean-Pierre

2016-01-01

In clinical genomics, the continuous evolution of bioinformatic algorithms and sequencing platforms makes it beneficial to store patients’ complete aligned genomic data in addition to variant calls relative to a reference sequence. Due to the large size of human genome sequence data files (varying from 30 GB to 200 GB depending on coverage), two major challenges facing genomics laboratories are the costs of storage and the efficiency of the initial data processing. In addition, privacy of genomic data is becoming an increasingly serious concern, yet no standard data storage solutions exist that enable compression, encryption, and selective retrieval. Here we present a privacy-preserving solution named SECRAM (Selective retrieval on Encrypted and Compressed Reference-oriented Alignment Map) for the secure storage of compressed aligned genomic data. Our solution enables selective retrieval of encrypted data and improves the efficiency of downstream analysis (e.g., variant calling). Compared with BAM, the de facto standard for storing aligned genomic data, SECRAM uses 18% less storage. Compared with CRAM, one of the most compressed nonencrypted formats (using 34% less storage than BAM), SECRAM maintains efficient compression and downstream data processing, while allowing for unprecedented levels of security in genomic data storage. Compared with previous work, the distinguishing features of SECRAM are that (1) it is position-based instead of read-based, and (2) it allows random querying of a subregion from a BAM-like file in an encrypted form. Our method thus offers a space-saving, privacy-preserving, and effective solution for the storage of clinical genomic data. PMID:27789525

Growth of Listeria monocytogenes in pasteurized vanilla cream pudding as affected by storage temperature and the presence of cinnamon extract.

PubMed

Lianou, Alexandra; Moschonas, Galatios; Nychas, George-John E; Panagou, Efstathios Z

2018-04-01

The objective of the present study was the assessment and quantitative description of the growth behavior of Listeria monocytogenes as a function of temperature in vanilla cream pudding, formulated with or without cinnamon extract. Commercially prepared pasteurized vanilla cream pudding, formulated with (0.1% w/w) or without cinnamon extract, was inoculated with a five-strain mixture of L. monocytogenes (ca. 2logCFU/g) and stored aerobically at 4, 8, 12 and 16°C. At appropriate time intervals, L. monocytogenes populations were determined, and the primary model of Baranyi and Roberts was fitted to the derived microbiological data for the estimation of the pathogen's growth kinetic parameters. The effect of temperature on maximum specific growth rate (μ max ) was then modeled for each product type using a square-root-type model, and the developed models were validated using independent growth data generated during storage of inoculated vanilla cream samples under dynamic temperature conditions. Although the kinetic behavior of the pathogen was similar in cream with and without cinnamon extract during storage at higher temperatures, significant (P<0.05) differences were observed between the two product types at 4°C. With regard to secondary modelling, the estimated values of T min for cream with and without cinnamon extract were 0.39°C and -2.54°C, respectively, while the dynamic models exhibited satisfactory performance. Finally, as demonstrated by the findings of pulsed-field gel electrophoresis, both temperature and cinnamon extract affected the pathogen's strains dominating during storage. According to the collected data, cinnamon extract exhibits an important potential of enhancing the microbiological safety of vanilla cream pudding, provided that efficient temperature control is in place. The developed models should be useful in quantitative microbial risk assessment regarding the studied cream products. Copyright © 2017 Elsevier Ltd. All rights reserved.

Basin Scale Estimates of Evapotranspiration Using GRACE and other Observations

NASA Technical Reports Server (NTRS)

Rodell, M.; Famiglietti, J. S.; Chen, J.; Seneviratne, S. I.; Viterbo, P.; Holl, S.; Wilson, C. R.

2004-01-01

Evapotranspiration is integral to studies of the Earth system, yet it is difficult to measure on regional scales. One estimation technique is a terrestrial water budget, i.e., total precipitation minus the sum of evapotranspiration and net runoff equals the change in water storage. Gravity Recovery and Climate Experiment (GRACE) satellite gravity observations are now enabling closure of this equation by providing the terrestrial water storage change. Equations are presented here for estimating evapotranspiration using observation based information, taking into account the unique nature of GRACE observations. GRACE water storage changes are first substantiated by comparing with results from a land surface model and a combined atmospheric-terrestrial water budget approach. Evapotranspiration is then estimated for 14 time periods over the Mississippi River basin and compared with output from three modeling systems. The GRACE estimates generally lay in the middle of the models and may provide skill in evaluating modeled evapotranspiration.

Comparison of irrigation pumpage with change in ground-water storage in the High Plains aquifer in Chase, Dundy, and Perkins counties, Nebraska, 1975-83

USGS Publications Warehouse

Heimes, F.J.; Ferrigno, C.F.; Gutentag, E.D.; Lucky, R.R.; Stephens, D.M.; Weeks, J.B.

1987-01-01

The relation between pumpage and change in storage was evaluated for most of a three-county area in southwestern Nebraska from 1975 through 1983. Initial comparison of the 1975-83 pumpage with change in storage in the study area indicated that the 1 ,042,300 acre-ft of change in storage was only about 30% of the 3,425,000 acre-ft of pumpage. An evaluation of the data used to calculate pumpage and change in storage indicated that there was a relatively large potential for error in estimates of specific yield. As a result, minimum and maximum values of specific yield were estimated and used to recalculate change in storage. Estimates also were derived for the minimum and maximum amounts of recharge that could occur as a result of cultivation practices. The minimum and maximum estimates for specific yield and for recharge from cultivation practices were used to compute a range of values for the potential amount of additional recharge that occurred as a result of irrigation. The minimum and maximum amounts of recharge that could be caused by irrigation in the study area were 953,200 acre-ft (28% of pumpage) and 2,611,200 acre-ft (76% of pumpage), respectively. These values indicate that a substantial percentage of the water pumped from the aquifer is resupplied to storage in the aquifer as a result of a combination of irrigation return flow and enhanced recharge from precipitation that results from cultivation and irrigation practices. (Author 's abstract)

Experimental Analysis of Voltage Drop Compensation in a DC Electrified Railway by Introducing an Energy Storage System Incorporating EDLCs

NASA Astrophysics Data System (ADS)

Konishi, Takeshi; Hase, Shin-Ichi; Nakamichi, Yoshinobu; Nara, Hidetaka; Uemura, Tadashi

Interest has been shown in the concept of an energy storage system aimed at leveling load and improving energy efficiency by charging during vehicle regeneration and discharging during running. Such a system represents an efficient countermeasure against pantograph point voltage drop, power load fluctuation and regenerative power loss. We selected an EDLC model as an energy storage medium and a step-up/step-down chopper as a power converter to exchange power between the storage medium and overhead lines. Basic verification was conducted using a mini-model for DC 400V, demonstrating characteristics suitable for its use as an energy storage system. Based on these results, an energy storage system was built for DC 600V and a verification test conducted in conjunction with the Enoshima Electric Railway Co. Ltd. This paper gives its experimental analysis of voltage drop compensation in a DC electrified railway and some discussions based on the test.

Heat storage in forest biomass improves energy balance closure

NASA Astrophysics Data System (ADS)

Lindroth, A.; Mölder, M.; Lagergren, F.

2010-01-01

Temperature measurements in trunks and branches in a mature ca. 100 years-old mixed pine and spruce forest in central Sweden were used to estimate the heat storage in the tree biomass. The estimated heat flux in the sample trees and data on biomass distributions were used to scale up to stand level biomass heat fluxes. The rate of change of sensible and latent heat storage in the air layer below the level of the flux measurements was estimated from air temperature and humidity profile measurements and soil heat flux was estimated from heat flux plates and soil temperature measurements. The fluxes of sensible and latent heat from the forest were measured with an eddy covariance system in a tower. The analysis was made for a two-month period in summer of 1995. The tree biomass heat flux was the largest of the estimated storage components and varied between 40 and -35 W m-2 on summer days with nice weather. Averaged over two months the diurnal maximum of total heat storage was 45 W m-2 and the minimum was -35 W m-2. The soil heat flux and the sensible heat storage in air were out of phase with the biomass flux and they reached maximum values that were about 75% of the maximum of the tree biomass heat storage. The energy balance closure improved significantly when the total heat storage was added to the turbulent fluxes. The slope of a regression line with sum of fluxes and storage as independent and net radiation as dependent variable, increased from 0.86 to 0.95 for half-hourly data and the scatter was also reduced. The most significant finding was, however, that during nights with strongly stable conditions when the sensible heat flux dropped to nearly zero, the total storage matched the net radiation very well. Another interesting result was that the mean energy imbalance started to increase when the Richardson number became more negative than ca. -0.1. In fact, the largest energy deficit occurred at maximum instability. Our conclusion is that eddy covariance measurements can function well during stable conditions but that the functioning under strong instabilities might be a so far unforeseen problem.

Heat storage in forest biomass significantly improves energy balance closure particularly during stable conditions

NASA Astrophysics Data System (ADS)

Lindroth, A.; Mölder, M.; Lagergren, F.

2009-08-01

Temperature measurements in trunks and branches in a mature ca. 100 years-old mixed pine and spruce forest in central Sweden were used to estimate the heat storage in the tree biomass. The estimated heat flux in the sample trees and data on biomass distributions were used to scale up to stand level biomass heat fluxes. The rate of change of sensible and latent heat storage in the air layer below the level of the flux measurements was estimated from air temperature and humidity profile measurements and soil heat flux was estimated from heat flux plates and soil temperature measurements. The fluxes of sensible and latent heat from the forest were measured with an eddy covariance system in a tower. The analysis was made for a two-month period in summer of 1995. The tree biomass heat flux was the largest of the estimated storage components and varied between 40 and -35 W m-2 on summer days with nice weather. Averaged over two months the diurnal maximum of total heat storage was 45 W m-2 and the minimum was -35 W m-2. The soil heat flux and the sensible heat storage in air were out of phase with the biomass flux and they reached maximum values that were about 75% of the maximum of the tree biomass heat storage. The energy balance closure improved significantly when the total heat storage was added to the turbulent fluxes. The slope of a regression line with sum of fluxes and storage as independent and net radiation as dependent variable, increased from 0.86 to 0.95 for half-hourly data and the scatter was also reduced. The most significant finding was, however, that during nights with strongly stable conditions when the sensible heat flux dropped to nearly zero, the total storage matched the net radiation nearly perfectly. Another interesting result was that the mean energy imbalance started to increase when the Richardson number became more negative than ca. -0.1. In fact, the largest energy deficit occurred at maximum instability. Our conclusion is that eddy covariance measurements can function well during stable conditions but that the functioning under strong instabilities might be a so far unforeseen problem.

Thin Film Photovoltaic Cells on Flexible Substrates Integrated with Energy Storage

DTIC Science & Technology

2011-11-30

mV[19]. In 2008, Katagiri et al ’ obtained an efficiency of 6.7% by Physical vapor methods[20]. In 2010, Mitzi et al reported an efficiency of 9.6...Films 517 (2009) 2455. [21] T.K. Todorov, K.B. Reuter, D.B. Mitzi , Adv Mater 22 (2010) El 56. 3. Energy Storage: Ultracapacitors - Professor Rastogi

mz5: space- and time-efficient storage of mass spectrometry data sets.

PubMed

Wilhelm, Mathias; Kirchner, Marc; Steen, Judith A J; Steen, Hanno

2012-01-01

Across a host of MS-driven-omics fields, researchers witness the acquisition of ever increasing amounts of high throughput MS data and face the need for their compact yet efficiently accessible storage. Addressing the need for an open data exchange format, the Proteomics Standards Initiative and the Seattle Proteome Center at the Institute for Systems Biology independently developed the mzData and mzXML formats, respectively. In a subsequent joint effort, they defined an ontology and associated controlled vocabulary that specifies the contents of MS data files, implemented as the newer mzML format. All three formats are based on XML and are thus not particularly efficient in either storage space requirements or read/write speed. This contribution introduces mz5, a complete reimplementation of the mzML ontology that is based on the efficient, industrial strength storage backend HDF5. Compared with the current mzML standard, this strategy yields an average file size reduction to ∼54% and increases linear read and write speeds ∼3-4-fold. The format is implemented as part of the ProteoWizard project and is available under a permissive Apache license. Additional information and download links are available from http://software.steenlab.org/mz5.

Monitoring in inline storage sewers for stormwater treatment to determine efficiencies.

PubMed

Frehmann, T; Mietzel, T; Kutzner, R; Spengler, B; Geiger, W F

2004-01-01

A special structure of combined sewer overflow tanks is the inline storage sewer with downstream discharge (SKU). This layout has the advantage that besides the sewer system, no other structures are required for storm water treatment. Consequently only very little space is required and compared to combined sewer overflow tanks, there is an enormous potential in reducing costs during construction. To investigate the efficiency of an inline storage sewer, a monitoring station was established in Dortmund-Scharnhorst, Germany. The monitoring station was in operation for a period of 2.5 years. Within this period water samples were taken during a total of 20 discharge events. Besides the complete hydraulic data collection, seven water samplers took more than 5,000 water samples during dry and wet weather. This adds up to a total of more than 20,000 individual lab analyses. The average of the total efficiency for the SKU-West is 86%. 29% of this efficiency can be attributed to the throttle flow. The remaining 57% can be divided into a part of 48% that can be attributed to the process storage and 9% that can be attributed to sedimentation and erosion process.

Optimization of storage tank locations in an urban stormwater drainage system using a two-stage approach.

PubMed

Wang, Mingming; Sun, Yuanxiang; Sweetapple, Chris

2017-12-15

Storage is important for flood mitigation and non-point source pollution control. However, to seek a cost-effective design scheme for storage tanks is very complex. This paper presents a two-stage optimization framework to find an optimal scheme for storage tanks using storm water management model (SWMM). The objectives are to minimize flooding, total suspended solids (TSS) load and storage cost. The framework includes two modules: (i) the analytical module, which evaluates and ranks the flooding nodes with the analytic hierarchy process (AHP) using two indicators (flood depth and flood duration), and then obtains the preliminary scheme by calculating two efficiency indicators (flood reduction efficiency and TSS reduction efficiency); (ii) the iteration module, which obtains an optimal scheme using a generalized pattern search (GPS) method based on the preliminary scheme generated by the analytical module. The proposed approach was applied to a catchment in CZ city, China, to test its capability in choosing design alternatives. Different rainfall scenarios are considered to test its robustness. The results demonstrate that the optimal framework is feasible, and the optimization is fast based on the preliminary scheme. The optimized scheme is better than the preliminary scheme for reducing runoff and pollutant loads under a given storage cost. The multi-objective optimization framework presented in this paper may be useful in finding the best scheme of storage tanks or low impact development (LID) controls. Copyright © 2017 Elsevier Ltd. All rights reserved.

Evaluation of gravimetric techniques to estimate the microvascular filtration coefficient

PubMed Central

Dongaonkar, R. M.; Laine, G. A.; Stewart, R. H.

2011-01-01

Microvascular permeability to water is characterized by the microvascular filtration coefficient (Kf). Conventional gravimetric techniques to estimate Kf rely on data obtained from either transient or steady-state increases in organ weight in response to increases in microvascular pressure. Both techniques result in considerably different estimates and neither account for interstitial fluid storage and lymphatic return. We therefore developed a theoretical framework to evaluate Kf estimation techniques by 1) comparing conventional techniques to a novel technique that includes effects of interstitial fluid storage and lymphatic return, 2) evaluating the ability of conventional techniques to reproduce Kf from simulated gravimetric data generated by a realistic interstitial fluid balance model, 3) analyzing new data collected from rat intestine, and 4) analyzing previously reported data. These approaches revealed that the steady-state gravimetric technique yields estimates that are not directly related to Kf and are in some cases directly proportional to interstitial compliance. However, the transient gravimetric technique yields accurate estimates in some organs, because the typical experimental duration minimizes the effects of interstitial fluid storage and lymphatic return. Furthermore, our analytical framework reveals that the supposed requirement of tying off all draining lymphatic vessels for the transient technique is unnecessary. Finally, our numerical simulations indicate that our comprehensive technique accurately reproduces the value of Kf in all organs, is not confounded by interstitial storage and lymphatic return, and provides corroboration of the estimate from the transient technique. PMID:21346245

A scalable and flexible hybrid energy storage system design and implementation

NASA Astrophysics Data System (ADS)

Kim, Younghyun; Koh, Jason; Xie, Qing; Wang, Yanzhi; Chang, Naehyuck; Pedram, Massoud

2014-06-01

Energy storage systems (ESS) are becoming one of the most important components that noticeably change overall system performance in various applications, ranging from the power grid infrastructure to electric vehicles (EV) and portable electronics. However, a homogeneous ESS is subject to limited characteristics in terms of cost, efficiency, lifetime, etc., by the energy storage technology that comprises the ESS. On the other hand, hybrid ESS (HESS) are a viable solution for a practical ESS with currently available technologies as they have potential to overcome such limitations by exploiting only advantages of heterogeneous energy storage technologies while hiding their drawbacks. However, the HESS concept basically mandates sophisticated design and control to actually make the benefits happen. The HESS architecture should be able to provide controllability of many parts, which are often fixed in homogeneous ESS, and novel management policies should be able to utilize the control features. This paper introduces a complete design practice of a HESS prototype to demonstrate scalability, flexibility, and energy efficiency. It is composed of three heterogenous energy storage elements: lead-acid batteries, lithium-ion batteries, and supercapacitors. We demonstrate a novel system control methodology and enhanced energy efficiency through this design practice.

Electrodynamic tether system study

NASA Technical Reports Server (NTRS)

1987-01-01

The purpose of this program is to define an Electrodynamic Tether System (ETS) that could be erected from the space station and/or platforms to function as an energy storage device. A schematic representation of the ETS concept mounted on the space station is presented. In addition to the hardware design and configuration efforts, studies are also documented involving simulations of the Earth's magnetic fields and the effects this has on overall system efficiency calculations. Also discussed are some preliminary computer simulations of orbit perturbations caused by the cyclic/night operations of the ETS. System cost estimates, an outline for future development testing for the ETS system, and conclusions and recommendations are also provided.

Optimization and Performance Study of Select Heating Ventilation and Air Conditioning Technologies for Commercial Buildings

NASA Astrophysics Data System (ADS)

Kamal, Rajeev

Buildings contribute a significant part to the electricity demand profile and peak demand for the electrical utilities. The addition of renewable energy generation adds additional variability and uncertainty to the power system. Demand side management in the buildings can help improve the demand profile for the utilities by shifting some of the demand from peak to off-peak times. Heating, ventilation and air-conditioning contribute around 45% to the overall demand of a building. This research studies two strategies for reducing the peak as well as shifting some demand from peak to off-peak periods in commercial buildings: 1. Use of gas heat pumps in place of electric heat pumps, and 2. Shifting demand for air conditioning from peak to off-peak by thermal energy storage in chilled water and ice. The first part of this study evaluates the field performance of gas engine-driven heat pumps (GEHP) tested in a commercial building in Florida. Four GEHP units of 8 Tons of Refrigeration (TR) capacity each providing air-conditioning to seven thermal zones in a commercial building, were instrumented for measuring their performance. The operation of these GEHPs was recorded for ten months, analyzed and compared with prior results reported in the literature. The instantaneous COPunit of these systems varied from 0.1 to 1.4 during typical summer week operation. The COP was low because the gas engines for the heat pumps were being used for loads that were much lower than design capacity which resulted in much lower efficiencies than expected. The performance of equivalent electric heat pump was simulated from a building energy model developed to mimic the measured building loads. An economic comparison of GEHPs and conventional electrical heat pumps was done based on the measured and simulated results. The average performance of the GEHP units was estimated to lie between those of EER-9.2 and EER-11.8 systems. The performance of GEHP systems suffers due to lower efficiency at part load operation. The study highlighted the need for optimum system sizing for GEHP/HVAC systems to meet the building load to obtain better performance in buildings. The second part of this study focusses on using chilled water or ice as thermal energy storage for shifting the air conditioning load from peak to off-peak in a commercial building. Thermal energy storage can play a very important role in providing demand-side management for diversifying the utility demand from buildings. Model of a large commercial office building is developed with thermal storage for cooling for peak power shifting. Three variations of the model were developed and analyzed for their performance with 1) ice storage, 2) chilled water storage with mixed storage tank and 3) chilled water storage with stratified tank, using EnergyPlus 8.5 software developed by the US Department of Energy. Operation strategy with tactical control to incorporate peak power schedule was developed using energy management system (EMS). The modeled HVAC system was optimized for minimum cost with the optimal storage capacity and chiller size using JEPlus. Based on the simulation, an optimal storage capacity of 40-45 GJ was estimated for the large office building model along with 40% smaller chiller capacity resulting in higher chiller part-load performance. Additionally, the auxiliary system like pump and condenser were also optimized to smaller capacities and thus resulting in less power demand during operation. The overall annual saving potential was found in the range of 7-10% for cooling electricity use resulting in 10-17% reduction in costs to the consumer. A possible annual peak shifting of 25-78% was found from the simulation results after comparing with the reference models. Adopting TES in commercial buildings and achieving 25% peak shifting could result in a reduction in peak summer demand of 1398 MW in Tampa.

Efficient storage mechanisms for building better supercapacitors

NASA Astrophysics Data System (ADS)

Salanne, M.; Rotenberg, B.; Naoi, K.; Kaneko, K.; Taberna, P.-L.; Grey, C. P.; Dunn, B.; Simon, P.

2016-06-01

Supercapacitors are electrochemical energy storage devices that operate on the simple mechanism of adsorption of ions from an electrolyte on a high-surface-area electrode. Over the past decade, the performance of supercapacitors has greatly improved, as electrode materials have been tuned at the nanoscale and electrolytes have gained an active role, enabling more efficient storage mechanisms. In porous carbon materials with subnanometre pores, the desolvation of the ions leads to surprisingly high capacitances. Oxide materials store charge by surface redox reactions, leading to the pseudocapacitive effect. Understanding the physical mechanisms underlying charge storage in these materials is important for further development of supercapacitors. Here we review recent progress, from both in situ experiments and advanced simulation techniques, in understanding the charge storage mechanism in carbon- and oxide-based supercapacitors. We also discuss the challenges that still need to be addressed for building better supercapacitors.

Enhanced electrocaloric analysis and energy-storage performance of lanthanum modified lead titanate ceramics for potential solid-state refrigeration applications.

PubMed

Zhang, Tian-Fu; Huang, Xian-Xiong; Tang, Xin-Gui; Jiang, Yan-Ping; Liu, Qiu-Xiang; Lu, Biao; Lu, Sheng-Guo

2018-01-10

The unique properties and great variety of relaxer ferroelectrics make them highly attractive in energy-storage and solid-state refrigeration technologies. In this work, lanthanum modified lead titanate ceramics are prepared and studied. The giant electrocaloric effect in lanthanum modified lead titanate ceramics is revealed for the first time. Large refrigeration efficiency (27.4) and high adiabatic temperature change (1.67 K) are achieved by indirect analysis. Direct measurements of electrocaloric effect show that reversible adiabatic temperature change is also about 1.67 K, which exceeds many electrocaloric effect values in current direct measured electrocaloric studies. Both theoretical calculated and direct measured electrocaloric effects are in good agreements in high temperatures. Temperature and electric field related energy storage properties are also analyzed, maximum energy-storage density and energy-storage efficiency are about 0.31 J/cm 3 and 91.2%, respectively.

Optimization of Norbornadiene Compounds for Solar Thermal Storage by First-Principles Calculations.

PubMed

Kuisma, Mikael; Lundin, Angelica; Moth-Poulsen, Kasper; Hyldgaard, Per; Erhart, Paul

2016-07-21

Molecular photoswitches capable of storing solar energy are interesting candidates for future renewable energy applications. Here, using quantum mechanical calculations, we carry out a systematic screening of crucial optical (solar spectrum match) and thermal (storage energy density) properties of 64 such compounds based on the norbornadiene-quadricyclane system. Whereas a substantial number of these molecules reach the theoretical maximum solar power conversion efficiency, this requires a strong red-shift of the absorption spectrum, which causes undesirable absorption by the photoisomer as well as reduced thermal stability. These compounds typically also have a large molecular mass, leading to low storage densities. By contrast, single-substituted systems achieve a good compromise between efficiency and storage density, while avoiding competing absorption by the photo-isomer. This establishes guiding principles for the future development of molecular solar thermal storage systems. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Development of a differentially balanced magnetic bearing and control system for use with a flywheel energy storage system

NASA Technical Reports Server (NTRS)

Higgins, Mark A.; Plant, David P.; Ries, Douglas M.; Kirk, James A.; Anand, Davinder K.

1992-01-01

The purpose of a magnetically suspended flywheel energy storage system for electric utility load leveling is to provide a means to store energy during times when energy is inexpensive to produce and then return it to the customer during times of peak power demand when generated energy is most expensive. The design of a 20 kWh flywheel energy storage system for electric utility load leveling applications involves the successful integration of a number of advanced technologies so as to minimize the size and cost of the system without affecting its efficiency and reliability. The flywheel energy storage system uses a carbon epoxy flywheel, two specially designed low loss magnetic bearings, a high efficiency motor generator, and a 60 cycle AC power converter all integrated through a microprocessor controller. The basic design is discussed of each of the components that is used in the energy storage design.

Technical challenges and future direction for high-efficiency metal hydride thermal energy storage systems

NASA Astrophysics Data System (ADS)

Ward, Patrick A.; Corgnale, Claudio; Teprovich, Joseph A.; Motyka, Theodore; Hardy, Bruce; Sheppard, Drew; Buckley, Craig; Zidan, Ragaiy

2016-04-01

Recently, there has been increasing interest in thermal energy storage (TES) systems for concentrated solar power (CSP) plants, which allow for continuous operation when sunlight is unavailable. Thermochemical energy storage materials have the advantage of much higher energy densities than latent or sensible heat materials. Furthermore, thermochemical energy storage systems based on metal hydrides have been gaining great interest for having the advantage of higher energy densities, better reversibility, and high enthalpies. However, in order to achieve higher efficiencies desired of a thermal storage system by the US Department of Energy, the system is required to operate at temperatures >600 °C. Operation at temperatures >600 °C presents challenges including material selection, hydrogen embrittlement and permeation of containment vessels, appropriate selection of heat transfer fluids, and cost. Herein, the technical difficulties and proposed solutions associated with the use of metal hydrides as TES materials in CSP applications are discussed and evaluated.

Graphene Based Ultra-Capacitors for Safer, More Efficient Energy Storage

NASA Technical Reports Server (NTRS)

Roberson, Luke B.; Mackey, Paul J.; Zide, Carson J.

2016-01-01

Current power storage methods must be continuously improved in order to keep up with the increasingly competitive electronics industry. This technological advancement is also essential for the continuation of deep space exploration. Today's energy storage industry relies heavily on the use of dangerous and corrosive chemicals such as lithium and phosphoric acid. These chemicals can prove hazardous to the user if the device is ruptured. Similarly they can damage the environment if they are disposed of improperly. A safer, more efficient alternative is needed across a wide range of NASA missions. One solution would a solid-state carbon based energy storage device. Carbon is a safer, less environmentally hazardous alternative to current energy storage materials. Using the amorphous carbon nanostructure, graphene, this idea of a safer portable energy is possible. Graphene was electrochemically produced in the lab and several coin cell devices were built this summer to create a working prototype of a solid-state graphene battery.

Final Report UCLA-Thermochemical Storage with Anhydrous Ammonia

DOE Office of Scientific and Technical Information (OSTI.GOV)

Lavine, Adrienne

In ammonia-based thermochemical energy storage (TCES), ammonia is dissociated endothermically as it absorbs solar energy during the daytime. When energy is required, the reverse reaction releases energy to heat a working fluid such as steam, to produce electricity. Ammonia-based TCES has great advantages of simplicity, low cost reactants, and a strong industrial base in the conventional ammonia industry. The concept has been demonstrated over three decades of research at Australian National University, achieving a 24-hour demonstration of a complete system. At the start of this project, three challenges were identified that would have to be addressed to show that themore » system is technically and economically viable for incorporation into a CSP plant with an advanced, high temperature power block. All three of these challenges have now been addressed: 1. The ammonia synthesis reaction had not, to our knowledge, been carried out at temperatures consistent with modern power blocks (i.e., ~650°C). The technical feasibility of operating a reactor under high-temperature, near-equilibrium conditions was an unknown, and was therefore a technical risk. The project has successfully demonstrated steam heating to 650°C and energy recovery to steam at the 5 kWt level. 2. The ammonia system has a relatively low enthalpy of reaction combined with gas phase reactants. This is not a direct disadvantage since the reactants themselves are low cost. The challenge lies in storing the required volume of reactants cost effectively. Therefore, a second key goal was to show, through techno-economic analysis, that underground storage technologies can be used to store the energy-rich gas at a cost that is consistent with the SunShot cost goal. We have identified two promising technologies for gas storage: storage in salt caverns has an estimated cost of 1(USD)/kWht and storage in drilled shafts could be on the order of 7(USD)/kWht. Together these two options answer the technical challenge associated with storage of gas phase components. 3. While this project is primarily concerned with high-temperature heat recovery and methods to store the gaseous components, it is also important to consider the feasibility of the entire system. Consequently, an additional goal was to perform analysis to show the feasibility of integrating endothermic reactors within a tower receiver. A conceptual design of an ammonia dissociation receiver/reactor has been developed that fits into the same size cylindrical envelope as the molten salt receiver in SAM, and has the same design thermal capacity. The calculated thermal efficiency of this receiver is 94.6%. Thus, this investigation has established the technical feasibility of a surround field tower system using ammonia dissociation. With these challenges addressed, we proceeded to design a full-scale synthesis and heat recovery system. A model was developed and validated by comparison with our experimental data. A parametric study showed, among other things, the importance of using small tube diameters and spacing to enhance heat transfer. Multi-parameter optimization was used to find a design that minimizes the wall material volume. Finally, cost estimation shows that the ammonia system has good prospects of meeting the Sunshot 15(USD)/kWht target: estimated costs of the entire synthesis system for the 220 MWt plant with 6 hours of storage are 13(USD)/kWht using salt cavern storage and 18(USD)/kWht using shaft drilling. Costs per kWht are even lower with more hours of storage. With the established technology of ammonia synthesis as a starting point, the successes of the project have mitigated technical risks associated with high-temperature synthesis reaction, underground storage, and tower receiver design. Estimated costs are less than 15(USD)/kWht with salt cavern storage. It is now possible to map a time line to commercial deployment that is likely to be shorter and less risky than other thermochemical cycles under active investigation. UCLA has filed a patent that protects the new ideas developed during this project. Discussions are ongoing with potential investors with the aim of partnering for further work. As well as immediate improvements and extra work with the existing experimental system, a key goal is to extend it to a small solar-driven project at an early opportunity.« less

Efficient proof of ownership for cloud storage systems

NASA Astrophysics Data System (ADS)

Zhong, Weiwei; Liu, Zhusong

2017-08-01

Cloud storage system through the deduplication technology to save disk space and bandwidth, but the use of this technology has appeared targeted security attacks: the attacker can deceive the server to obtain ownership of the file by get the hash value of original file. In order to solve the above security problems and the different security requirements of the files in the cloud storage system, an efficient and information-theoretical secure proof of ownership sceme is proposed to support the file rating. Through the K-means algorithm to implement file rating, and use random seed technology and pre-calculation method to achieve safe and efficient proof of ownership scheme. Finally, the scheme is information-theoretical secure, and achieve better performance in the most sensitive areas of client-side I/O and computation.

High discharge efficiency of (Sr, Pb, Bi) TiO3 relaxor ceramics for energy-storage application

NASA Astrophysics Data System (ADS)

Chao, Mingming; Liu, Jingsong; Zeng, Mengshi; Wang, Debin; Yu, Hongtao; Yuan, Ying; Zhang, Shuren

2018-05-01

We report herein on the energy storage and discharge properties of the relaxor ferroelectric ceramic Sr0.8Pb0.1Bi0.1TiO3 (SPBT). This material has a slanted hysteresis loop, and all samples show low remnant polarization and low coercive field, which leads to a high discharge efficiency. The maximum polarization is 10.1 μC/cm2, the minimum coercive field is 0.229 kV/cm, and the maximum efficiency is 94.2%. The discharge current waveforms are sinusoidal, the first discharge period is 140 ns, and the power density is approximately 4.2 × 107 W/kg. The high discharge speed and high discharge power density indicate that SPBT ceramics are very promising materials for energy storage applications.

Potential active materials for photo-supercapacitor: A review

NASA Astrophysics Data System (ADS)

Ng, C. H.; Lim, H. N.; Hayase, S.; Harrison, I.; Pandikumar, A.; Huang, N. M.

2015-11-01

The need for an endless renewable energy supply, typically through the utilization of solar energy in most applications and systems, has driven the expansion, versatility, and diversification of marketed energy storage devices. Energy storage devices such as hybridized dye-sensitized solar cell (DSSC)-capacitors and DSSC-supercapacitors have been invented for energy reservation. The evolution and vast improvement of these devices in terms of their efficiencies and flexibilities have further sparked the invention of the photo-supercapacitor. The idea of coupling a DSSC and supercapacitor as a complete energy conversion and storage device arose because the solar energy absorbed by dye molecules can be efficiently transferred and converted to electrical energy by adopting a supercapacitor as the energy delivery system. The conversion efficiency of a photo-supercapacitor is mainly dependent on the use of active materials during its fabrication. The performances of the dye, photoactive metal oxide, counter electrode, redox electrolyte, and conducting polymer are the primary factors contributing to high-energy-efficient conversion, which enhances the performance and shelf-life of a photo-supercapacitor. Moreover, the introduction of compact layer as a primary adherent film has been earmarked as an effort in enhancing power conversion efficiency of solar cell. Additionally, the development of electrolyte-free solar cell such as the invention of hole-conductor or perovskite solar cell is currently being explored extensively. This paper reviews and analyzes the potential active materials for a photo-supercapacitor to enhance the conversion and storage efficiencies.

A technique for estimating time of concentration and storage coefficient values for Illinois streams

USGS Publications Warehouse

Graf, Julia B.; Garklavs, George; Oberg, Kevin A.

1982-01-01

Values of the unit hydrograph parameters time of concentration (TC) and storage coefficient (R) can be estimated for streams in Illinois by a two-step technique developed from data for 98 gaged basins in the State. The sum of TC and R is related to stream length (L) and main channel slope (S) by the relation (TC + R)e = 35.2L0.39S-0.78. The variable R/(TC + R) is not significantly correlated with drainage area, slope, or length, but does exhibit a regional trend. Regional values of R/(TC + R) are used with the computed values of (TC + R)e to solve for estimated values of time of concentration (TCe) and storage coefficient (Re). The use of the variable R/(TC + R) is thought to account for variations in unit hydrograph parameters caused by physiographic variables such as basin topography, flood-plain development, and basin storage characteristics. (USGS)

Chemical hydrogen storage material property guidelines for automotive applications

DOE Office of Scientific and Technical Information (OSTI.GOV)

Semelsberger, Troy; Brooks, Kriston P.

2015-04-01

Chemical hydrogen storage is the sought after hydrogen storage media for automotive applications because of the expected low pressure operation (<20 atm), moderate temperature operation (<200 C), system gravimetric capacities (>0.05 kg H2/kg system), and system volumetric capacities (>0.05 kg H2/L system). Currently, the primary shortcomings of chemical hydrogen storage are regeneration efficiency, fuel cost and fuel phase (i.e., solid or slurry phase). Understanding the required material properties to meet the DOE Technical Targets for Onboard Hydrogen Storage Systems is a critical knowledge gap in the hydrogen storage research community. This study presents a set of fluid-phase chemical hydrogen storagemore » material property guidelines for automotive applications meeting the 2017 DOE technical targets. Viable material properties were determined using a boiler-plate automotive system design. The fluid phase chemical hydrogen storage media considered in this study were neat liquids, solutions, and non-settling homogeneous slurries. Material properties examined include kinetics, heats of reaction, fuel-cell impurities, gravimetric and volumetric hydrogen storage capacities, and regeneration efficiency. The material properties, although not exhaustive, are an essential first step in identifying viable chemical hydrogen storage material propertiesdand most important, their implications on system mass, system volume and system performance.« less

Electrochemical Energy Storage for an Orbiting Space Station

NASA Technical Reports Server (NTRS)

Martin, R. E.

1981-01-01

The system weight of a multi hundred kilowatt fuel cell electrolysis cell energy storage system based upon alkaline electrochemical cell technology for use in a future orbiting space station in low Earth orbit (LEO) was studied. Preliminary system conceptual design, fuel cell module performance characteristics, subsystem and system weights, and overall system efficiency are identified. The impact of fuel cell module operating temperature and efficiency upon energy storage system weight is investigated. The weight of an advanced technology system featuring high strength filament wound reactant tanks and a fuel cell module employing lightweight graphite electrolyte reservoir plates is defined.

Themis - A solar power station

NASA Astrophysics Data System (ADS)

Hillairet, J.

The organization, goals, equipment, costs, and performance of the French Themis (Thermo-helio-electric-MW) project are outlined. The program was begun for both the domestic energy market and for export. The installation comprises a molten eutectic salt loop which receives heat from radiators situated in a central tower. The salt transfers the heat to water for steam generation of electricity. A storage tank holds enough molten salt to supply one day's reserve of power, 40 MWh. A field of heliostats directs the suns rays for an estimated 2400 hr/yr onto the central receiver aperture, while 11 additional parabolic concentrators provide sufficient heat to keep the salt reservoir at temperatures exceeding 200 C. In a test run of several months during the spring of 1982 the heliostats directed the sun's rays with an average efficiency of 75 percent, yielding 2.3 MW of power at a system efficiency of 20.5 percent in completely automatic operation.

Region-Based Prediction for Image Compression in the Cloud.

PubMed

Begaint, Jean; Thoreau, Dominique; Guillotel, Philippe; Guillemot, Christine

2018-04-01

Thanks to the increasing number of images stored in the cloud, external image similarities can be leveraged to efficiently compress images by exploiting inter-images correlations. In this paper, we propose a novel image prediction scheme for cloud storage. Unlike current state-of-the-art methods, we use a semi-local approach to exploit inter-image correlation. The reference image is first segmented into multiple planar regions determined from matched local features and super-pixels. The geometric and photometric disparities between the matched regions of the reference image and the current image are then compensated. Finally, multiple references are generated from the estimated compensation models and organized in a pseudo-sequence to differentially encode the input image using classical video coding tools. Experimental results demonstrate that the proposed approach yields significant rate-distortion performance improvements compared with the current image inter-coding solutions such as high efficiency video coding.

Estimating the supply and demand for deep geologic CO2 storage capacity over the course of the 21st Century: A meta-analysis of the literature

DOE Office of Scientific and Technical Information (OSTI.GOV)

Dooley, James J.

2013-08-05

Whether there is sufficient geologic CO2 storage capacity to allow CCS to play a significant role in mitigating climate change has been the subject of debate since the 1990s. This paper presents a meta- analysis of a large body of recently published literature to derive updated estimates of the global deep geologic storage resource as well as the potential demand for this geologic CO2 storage resource over the course of this century. This analysis reveals that, for greenhouse gas emissions mitigation scenarios that have end-of-century atmospheric CO2 concentrations of between 350 ppmv and 725 ppmv, the average demand for deepmore » geologic CO2 storage over the course of this century is between 410 GtCO2 and 1,670 GtCO2. The literature summarized here suggests that -- depending on the stringency of criteria applied to calculate storage capacity – global geologic CO2 storage capacity could be: 35,300 GtCO2 of “theoretical” capacity; 13,500 GtCO2 of “effective” capacity; 3,900 GtCO2, of “practical” capacity; and 290 GtCO2 of “matched” capacity for the few regions where this narrow definition of capacity has been calculated. The cumulative demand for geologic CO2 storage is likely quite small compared to global estimates of the deep geologic CO2 storage capacity, and therefore, a “lack” of deep geologic CO2 storage capacity is unlikely to be an impediment for the commercial adoption of CCS technologies in this century.« less

In premature infants there is no decrease in 24-hour posttransfusion allogeneic red blood cell recovery after 42 days of storage.

PubMed

Nalbant, Demet; Cancelas, José A; Mock, Donald M; Kyosseva, Svetlana V; Schmidt, Robert L; Cress, Gretchen A; Zimmerman, M Bridget; Strauss, Ronald G; Widness, John A

2018-02-01

Critically ill preterm very-low-birthweight (VLBW) neonates (birthweight ≤ 1.5 kg) frequently develop anemia that is treated with red blood cell (RBC) transfusions. Although RBCs transfused to adults demonstrate progressive decreases in posttransfusion 24-hour RBC recovery (PTR 24 ) during storage-to a mean of approximately 85% of the Food and Drug Administration-allowed 42-day storage-limited data in infants indicate no decrease in PTR 24 with storage. We hypothesized that PTR 24 of allogeneic RBCs transfused to anemic VLBW newborns: 1) will be greater than PTR 24 of autologous RBCs transfused into healthy adults and 2) will not decrease with increasing storage duration. RBCs were stored at 4°C for not more than 42 days in AS-3 or AS-5. PTR 24 was determined in 46 VLBW neonates using biotin-labeled RBCs and in 76 healthy adults using 51 Cr-labeled RBCs. Linear mixed-model analysis was used to estimate slopes and intercepts of PTR 24 versus duration of RBC storage. For VLBW newborns, the estimated slope of PTR 24 versus storage did not decrease with the duration of storage (p = 0.18) while for adults it did (p < 0.0001). These estimated slopes differed significantly in adults compared to newborns (p = 0.04). At the allowed 42-day storage limit, projected mean neonatal PTR 24 was 95.9%; for adults, it was 83.8% (p = 0.0002). These data provide evidence that storage duration of allogeneic RBCs intended for neonates can be increased without affecting PTR 24 . This conclusion supports the practice of transfusing RBCs stored up to 42 days for small-volume neonatal transfusions to limit donor exposure. © 2017 AABB.

Spatial and intertemporal arbitrage in the California natural gas transportation and storage network

NASA Astrophysics Data System (ADS)

Uria Martinez, Rocio

Intertemporal and spatial price differentials should provide the necessary signals to allocate a commodity efficiently inside a network. This dissertation investigates the extent to which decisions in the California natural gas transportation and storage system are taken with an eye on arbitrage opportunities. Daily data about flows into and out of storage facilities in California over 2002-2006 and daily spreads on the NYMEX futures market are used to investigate whether the injection profile is consistent with the "supply-of-storage" curve first observed by Working for wheat. Spatial price differentials between California and producing regions fluctuate throughout the year, even though spot prices at trading hubs across North America are highly correlated. In an analysis of "residual supply", gas volumes directed to California are examined for the influence of those fluctuations in locational differentials. Daily storage decisions in California do seem to be influenced by a daily price signal that combines the intertemporal spread and the locational basis between California and the Henry Hub, in addition to strong seasonal and weekly cycles. The timing and magnitude of the response differs across storage facilities depending on the regulatory requirements they face and the type of customers they serve. In contrast, deviations in spatial price differentials from the levels dictated by relative seasonality in California versus competing regions do not trigger significant reallocations of flows into California. Available data for estimation of both the supply-of-storage and residual-supply curves aggregate the behavior of many individuals whose motivations and attentiveness to prices vary. The resulting inventory and flow profiles differ from those that a social planner would choose to minimize operating costs throughout the network. Such optimal allocation is deduced from a quadratic programming model, calibrated to 2004-2005, that acknowledges relative seasonality in demand, trade-offs between transportation and storage costs, infrastructure configuration and regulatory requirements. A comparison of the simulated equilibrium with observed behavior identifies where the arbitrage opportunities lie. Moreover, scenario analysis of such as a LNG terminal or additional storage capacity in California reveals the considerable indirect network effects brought about by changes at any node or arc.

A preliminary estimate of changing calcrete carbon storage on land since the Last Glacial Maximum

NASA Astrophysics Data System (ADS)

Adams, J. M.; Post, W. M.

1999-05-01

The glacial-to-interglacial shift in land carbon storage is important in understanding the global carbon cycle and history of the climate system. While organic carbon storage on land appears to have been much less than present during the cold, dry glacial maximum, calcrete (soil carbonate) carbon storage would have been greater. Here we attempt a global estimation of this change; we use published figures for present soil carbonate by biome to estimate changing global soil carbonate storage, on the basis of reconstruction of vegetation areas for four timeslices since the Last Glacial Maximum. It appears that there would most likely have been around a 30-45% decrease in calcrete carbon on land accompanying the transition between glacial and interglacial conditions. This represents a change of about 500-400 GtC (outer error limits are estimated at 750-200 GtC) . In order to be weathered into dissolved bicarbonate, this would take up an additional 500-400 GtC (750-200 GtC) in CO 2 from ocean/atmosphere sources. An equivalent amount to the carbonate leaving the caliche reservoir on land may have accumulated in coral reefs and other calcareous marine sediments during the Holocene, liberating an equimolar quantity of CO 2 back into the ocean-atmosphere system as the bicarbonate ion breaks up.

A software tool to assess uncertainty in transient-storage model parameters using Monte Carlo simulations

USGS Publications Warehouse

Ward, Adam S.; Kelleher, Christa A.; Mason, Seth J. K.; Wagener, Thorsten; McIntyre, Neil; McGlynn, Brian L.; Runkel, Robert L.; Payn, Robert A.

2017-01-01

Researchers and practitioners alike often need to understand and characterize how water and solutes move through a stream in terms of the relative importance of in-stream and near-stream storage and transport processes. In-channel and subsurface storage processes are highly variable in space and time and difficult to measure. Storage estimates are commonly obtained using transient-storage models (TSMs) of the experimentally obtained solute-tracer test data. The TSM equations represent key transport and storage processes with a suite of numerical parameters. Parameter values are estimated via inverse modeling, in which parameter values are iteratively changed until model simulations closely match observed solute-tracer data. Several investigators have shown that TSM parameter estimates can be highly uncertain. When this is the case, parameter values cannot be used reliably to interpret stream-reach functioning. However, authors of most TSM studies do not evaluate or report parameter certainty. Here, we present a software tool linked to the One-dimensional Transport with Inflow and Storage (OTIS) model that enables researchers to conduct uncertainty analyses via Monte-Carlo parameter sampling and to visualize uncertainty and sensitivity results. We demonstrate application of our tool to 2 case studies and compare our results to output obtained from more traditional implementation of the OTIS model. We conclude by suggesting best practices for transient-storage modeling and recommend that future applications of TSMs include assessments of parameter certainty to support comparisons and more reliable interpretations of transport processes.

Global root zone storage capacity from satellite-based evaporation

NASA Astrophysics Data System (ADS)

Wang-Erlandsson, Lan; Bastiaanssen, Wim G. M.; Gao, Hongkai; Jägermeyr, Jonas; Senay, Gabriel B.; van Dijk, Albert I. J. M.; Guerschman, Juan P.; Keys, Patrick W.; Gordon, Line J.; Savenije, Hubert H. G.

2016-04-01

This study presents an "Earth observation-based" method for estimating root zone storage capacity - a critical, yet uncertain parameter in hydrological and land surface modelling. By assuming that vegetation optimises its root zone storage capacity to bridge critical dry periods, we were able to use state-of-the-art satellite-based evaporation data computed with independent energy balance equations to derive gridded root zone storage capacity at global scale. This approach does not require soil or vegetation information, is model independent, and is in principle scale independent. In contrast to a traditional look-up table approach, our method captures the variability in root zone storage capacity within land cover types, including in rainforests where direct measurements of root depths otherwise are scarce. Implementing the estimated root zone storage capacity in the global hydrological model STEAM (Simple Terrestrial Evaporation to Atmosphere Model) improved evaporation simulation overall, and in particular during the least evaporating months in sub-humid to humid regions with moderate to high seasonality. Our results suggest that several forest types are able to create a large storage to buffer for severe droughts (with a very long return period), in contrast to, for example, savannahs and woody savannahs (medium length return period), as well as grasslands, shrublands, and croplands (very short return period). The presented method to estimate root zone storage capacity eliminates the need for poor resolution soil and rooting depth data that form a limitation for achieving progress in the global land surface modelling community.

Case study - Dynamic pressure-limited capacity and costs of CO2 storage in the Mount Simon sandstone

USGS Publications Warehouse

Anderson, Steven T.; Jahediesfanjani, Hossein

2017-01-01

Widespread deployment of carbon capture and storage (CCS) is likely necessary to be able to satisfy baseload electricity demand, to maintain diversity in the energy mix, and to achieve climate and other objectives at the lowest cost. If all of the carbon dioxide (CO2) emissions from stationary sources (such as fossil-fuel burning power plants, and other industrial plants) in the United States needed to be captured and stored, it could be possible to store only a small fraction of this CO2 in oil and natural gas reservoirs, including as a result of CO2 utilization for enhanced oil recovery. The vast majority would have to be stored in saline-filled reservoirs (Dahowski et al., 2005). Given a lack of long-term commercial-scale CCS projects, there is considerable uncertainty in the risks, dynamic capacity, and their cost implications for geologic storage of CO2. Pressure buildup in the storage reservoir is expected to be a primary source of risk associated with CO2 storage, and could severely limit CO2 injection rates (dynamic storage capacities). Most cost estimates for commercial-scale deployment of CCS estimate CO2 storage costs under assumed availability of a theoretical capacity to store tens, hundreds, or even thousands of gigatons of CO2, without considering geologic heterogeneities, pressure limitations, or the time dimension. This could lead to underestimation of the costs of CO2 storage (Anderson, 2017). This paper considers the impacts of pressure limitations and geologic heterogeneity on the dynamic CO2 storage capacity and storage (injection) costs. In the U.S. Geological Survey (USGS)’s National Assessment of Geologic CO2 Storage Resources (USGS, 2013), the mean estimate of the theoretical storage capacity in the Mount Simon Sandstone was about 94 billion metric tons of CO2. However, our results suggest that the pressure-limited capacity after 50 years of injection could be only about 4% of the theoretical geologic storage capacity in this formation. Because this is far less than emissions of CO2 from stationary sources in the region around the Mount Simon Sandstone, the costs to accommodate the potential annual demand for CO2 storage in this formation could be significantly greater than current estimates. Our results could have implications for how long and to what extent decision makers can expect to be able to deploy CCS before transitioning to other low- or zero-carbon energy technologies.

Effective Hypothermic Storage of Human Pluripotent Stem Cell-Derived Cardiomyocytes Compatible With Global Distribution of Cells for Clinical Applications and Toxicology Testing

PubMed Central

Correia, Cláudia; Koshkin, Alexey; Carido, Madalena; Espinha, Nuno; Šarić, Tomo; Lima, Pedro A.; Alves, Paula M.

2016-01-01

To fully explore the potential of human pluripotent stem cell-derived cardiomyocytes (hPSC-CMs), efficient methods for storage and shipment of these cells are required. Here, we evaluated the feasibility to cold store monolayers and aggregates of functional CMs obtained from different PSC lines using a fully defined clinical-compatible preservation formulation and investigated the time frame that hPSC-CMs could be subjected to hypothermic storage. We showed that two-dimensional (2D) monolayers of hPSC-CMs can be efficiently stored at 4°C for 3 days without compromising cell viability. However, cell viability decreased when the cold storage interval was extended to 7 days. We demonstrated that hPSC-CMs are more resistant to prolonged hypothermic storage-induced cell injury in three-dimensional aggregates than in 2D monolayers, showing high cell recoveries (>70%) after 7 days of storage. Importantly, hPSC-CMs maintained their typical (ultra)structure, gene and protein expression profile, electrophysiological profiles, and drug responsiveness. Significance The applicability of human pluripotent stem cell-derived cardiomyocytes (hPSC-CMs) in the clinic/industry is highly dependent on the development of efficient methods for worldwide shipment of these cells. This study established effective clinically compatible strategies for cold (4°C) storage of hPSC-CMs cultured as two-dimensional (2D) monolayers and three-dimensional (3D) aggregates. Cell recovery of 2D monolayers of hPSC-CMs was found to be dependent on the time of storage, and 3D cell aggregates were more resistant to prolonged cold storage than 2D monolayers. Of note, it was demonstrated that 7 days of cold storage did not affect hPSC-CM ultrastructure, phenotype, or function. This study provides important insights into the cold preservation of PSC-CMs that could be valuable in improving global commercial distribution of hPSC-CMs. PMID:27025693

Effective Hypothermic Storage of Human Pluripotent Stem Cell-Derived Cardiomyocytes Compatible With Global Distribution of Cells for Clinical Applications and Toxicology Testing.

PubMed

Correia, Cláudia; Koshkin, Alexey; Carido, Madalena; Espinha, Nuno; Šarić, Tomo; Lima, Pedro A; Serra, Margarida; Alves, Paula M

2016-05-01

To fully explore the potential of human pluripotent stem cell-derived cardiomyocytes (hPSC-CMs), efficient methods for storage and shipment of these cells are required. Here, we evaluated the feasibility to cold store monolayers and aggregates of functional CMs obtained from different PSC lines using a fully defined clinical-compatible preservation formulation and investigated the time frame that hPSC-CMs could be subjected to hypothermic storage. We showed that two-dimensional (2D) monolayers of hPSC-CMs can be efficiently stored at 4°C for 3 days without compromising cell viability. However, cell viability decreased when the cold storage interval was extended to 7 days. We demonstrated that hPSC-CMs are more resistant to prolonged hypothermic storage-induced cell injury in three-dimensional aggregates than in 2D monolayers, showing high cell recoveries (>70%) after 7 days of storage. Importantly, hPSC-CMs maintained their typical (ultra)structure, gene and protein expression profile, electrophysiological profiles, and drug responsiveness. The applicability of human pluripotent stem cell-derived cardiomyocytes (hPSC-CMs) in the clinic/industry is highly dependent on the development of efficient methods for worldwide shipment of these cells. This study established effective clinically compatible strategies for cold (4°C) storage of hPSC-CMs cultured as two-dimensional (2D) monolayers and three-dimensional (3D) aggregates. Cell recovery of 2D monolayers of hPSC-CMs was found to be dependent on the time of storage, and 3D cell aggregates were more resistant to prolonged cold storage than 2D monolayers. Of note, it was demonstrated that 7 days of cold storage did not affect hPSC-CM ultrastructure, phenotype, or function. This study provides important insights into the cold preservation of PSC-CMs that could be valuable in improving global commercial distribution of hPSC-CMs. ©AlphaMed Press.

Simple Atomic Quantum Memory Suitable for Semiconductor Quantum Dot Single Photons

NASA Astrophysics Data System (ADS)

Wolters, Janik; Buser, Gianni; Horsley, Andrew; Béguin, Lucas; Jöckel, Andreas; Jahn, Jan-Philipp; Warburton, Richard J.; Treutlein, Philipp

2017-08-01

Quantum memories matched to single photon sources will form an important cornerstone of future quantum network technology. We demonstrate such a memory in warm Rb vapor with on-demand storage and retrieval, based on electromagnetically induced transparency. With an acceptance bandwidth of δ f =0.66 GHz , the memory is suitable for single photons emitted by semiconductor quantum dots. In this regime, vapor cell memories offer an excellent compromise between storage efficiency, storage time, noise level, and experimental complexity, and atomic collisions have negligible influence on the optical coherences. Operation of the memory is demonstrated using attenuated laser pulses on the single photon level. For a 50 ns storage time, we measure ηe2 e 50 ns=3.4 (3 )% end-to-end efficiency of the fiber-coupled memory, with a total intrinsic efficiency ηint=17 (3 )%. Straightforward technological improvements can boost the end-to-end-efficiency to ηe 2 e≈35 %; beyond that, increasing the optical depth and exploiting the Zeeman substructure of the atoms will allow such a memory to approach near unity efficiency. In the present memory, the unconditional read-out noise level of 9 ×10-3 photons is dominated by atomic fluorescence, and for input pulses containing on average μ1=0.27 (4 ) photons, the signal to noise level would be unity.

Simple Atomic Quantum Memory Suitable for Semiconductor Quantum Dot Single Photons.

PubMed

Wolters, Janik; Buser, Gianni; Horsley, Andrew; Béguin, Lucas; Jöckel, Andreas; Jahn, Jan-Philipp; Warburton, Richard J; Treutlein, Philipp

2017-08-11

Quantum memories matched to single photon sources will form an important cornerstone of future quantum network technology. We demonstrate such a memory in warm Rb vapor with on-demand storage and retrieval, based on electromagnetically induced transparency. With an acceptance bandwidth of δf=0.66  GHz, the memory is suitable for single photons emitted by semiconductor quantum dots. In this regime, vapor cell memories offer an excellent compromise between storage efficiency, storage time, noise level, and experimental complexity, and atomic collisions have negligible influence on the optical coherences. Operation of the memory is demonstrated using attenuated laser pulses on the single photon level. For a 50 ns storage time, we measure η_{e2e}^{50  ns}=3.4(3)% end-to-end efficiency of the fiber-coupled memory, with a total intrinsic efficiency η_{int}=17(3)%. Straightforward technological improvements can boost the end-to-end-efficiency to η_{e2e}≈35%; beyond that, increasing the optical depth and exploiting the Zeeman substructure of the atoms will allow such a memory to approach near unity efficiency. In the present memory, the unconditional read-out noise level of 9×10^{-3} photons is dominated by atomic fluorescence, and for input pulses containing on average μ_{1}=0.27(4) photons, the signal to noise level would be unity.

High Energy Density Regenerative Fuel Cell Systems for Terrestrial Applications

NASA Technical Reports Server (NTRS)

Burke, Kenneth A.

1999-01-01

Regenerative Fuel Cell System (RFCS) technology for energy storage has been a NASA power system concept for many years. Compared to battery-based energy storage systems, RFCS has received relatively little attention or resources for development because the energy density and electrical efficiency were not sufficiently attractive relative to advanced battery systems. Even today, RFCS remains at a very low technology readiness level (TRL of about 2 indicating feasibility has been demonstrated). Commercial development of the Proton Exchange Membrane (PEM) fuel cells for automobiles and other terrestrial applications and improvements in lightweight pressure vessel design to reduce weight and improve performance make possible a high energy density RFCS energy storage system. The results from this study of a lightweight RFCS energy storage system for a remotely piloted, solar-powered, high altitude aircraft indicate an energy density up to 790 w-h/kg with electrical efficiency of 53.4% is attainable. Such an energy storage system would allow a solar-powered aircraft to carry hundreds of kilograms of payload and remain in flight indefinitely for use in atmospheric research, earth observation, resource mapping. and telecommunications. Future developments in the areas of hydrogen and oxygen storage, pressure vessel design, higher temperature and higher- pressure fuel cell operation, unitized regenerative fuel cells, and commercial development of fuel cell technology will improve both the energy density and electrical efficiency of the RFCS.

Estimation of Groundwater Storage Change via GRACE over a Small Watershed - A Case Study over Konya Closed Basin

NASA Astrophysics Data System (ADS)

Karasu, İ. G.; Yilmaz, K. K.; Yilmaz, M. T.

2017-12-01

Estimation of the groundwater storage change and its interannual variability is critical over Konya Closed Basin which has excessive agricultural production. The annual total precipitation falling over the region is not sufficient to compensate the agricultural irrigation needs of the region. This leds many to use groundwater as the primary water resource, which resulted in significant drop in the groundwater levels. Accordingly, monitoring of the groundwater change is critical for sustainable water resources management. Gravity Recovery and Climate Experiment (GRACE) observations and Global Land Data Assimilation System (GLDAS) have been succesfully used over many locations to monitor the change in the groundwater storages. In this study, GRACE-derived terrestrial water storage estimates and GLDAS model soil moisture, canopy water, snow water equivalent and surface runoff simulations are used to retrieve the change in the groundwater storage over Konya Closed Basin streching over 50,000 km2 area. Initial comparisons show the declining trend in GRACE and GLDAS combined groundwater storage change estimates between 2002 and 2016 are consistent with the actual groundwater level change observed at ground stations. Even though many studies recommend GRACE observations to be used over regions larger than 100,000 km2 - 200,000 km2 area, results show GRACE remote sensing and GLDAS modeled groundwater change information are skillful to monitor the large mass changes occured as a result of the excessive groundwater exploitation over Konya Closed Basin with 50,000 km2 area.

Documentation of spreadsheets for the analysis of aquifer-test and slug-test data

USGS Publications Warehouse

Halford, Keith J.; Kuniansky, Eve L.

2002-01-01

Several spreadsheets have been developed for the analysis of aquifer-test and slug-test data. Each spreadsheet incorporates analytical solution(s) of the partial differential equation for ground-water flow to a well for a specific type of condition or aquifer. The derivations of the analytical solutions were previously published. Thus, this report abbreviates the theoretical discussion, but includes practical information about each method and the important assumptions for the applications of each method. These spreadsheets were written in Microsoft Excel 9.0 (use of trade names does not constitute endorsement by the USGS). Storage properties should not be estimated with many of the spreadsheets because most are for analyzing single-well tests. Estimation of storage properties from single-well tests is generally discouraged because single-well tests are affected by wellbore storage and by well construction. These non-ideal effects frequently cause estimates of storage to be erroneous by orders of magnitude. Additionally, single-well tests are not sensitive to aquifer-storage properties. Single-well tests include all slug tests (Bouwer and Rice Method, Cooper, Bredehoeft, Papadopulos Method, and van der Kamp Method), the Cooper-Jacob straight-line Method, Theis recovery-data analysis, Jacob-Lohman method for flowing wells in a confined aquifer, and the step-drawdown test. Multi-well test spreadsheets included in this report are; Hantush-Jacob Leaky Aquifer Method and Distance-Drawdown Methods. The distance-drawdown method is an equilibrium or steady-state method, thus storage cannot be estimated.

Nuclear Hybrid Energy System: Molten Salt Energy Storage (Summer Report 2013)

DOE Office of Scientific and Technical Information (OSTI.GOV)

Sabharwall, Piyush; mckellar, Michael George; Yoon, Su-Jong

2013-11-01

Effective energy use is a main focus and concern in the world today because of the growing demand for energy. The nuclear hybrid energy system (NHES) is a valuable technical concept that can potentially diversify and leverage existing energy technologies. This report considers a particular NHES design that combines multiple energy systems including a nuclear reactor, energy storage system (ESS), variable renewable generator (VRG), and additional process heat applications. Energy storage is an essential component of this particular NHES because its design allows the system to produce peak power while the nuclear reactor operates at constant power output. Many energymore » storage options are available, but this study mainly focuses on a molten salt ESS. The primary purpose of the molten salt ESS is to enable the nuclear reactor to be a purely constant heat source by acting as a heat storage component for the reactor during times of low demand, and providing additional capacity for thermo-electric power generation during times of peak electricity demand. This report will describe the rationale behind using a molten salt ESS and identify an efficient molten salt ESS configuration that may be used in load following power applications. Several criteria are considered for effective energy storage and are used to identify the most effective ESS within the NHES. Different types of energy storage are briefly described with their advantages and disadvantages. The general analysis to determine the most efficient molten salt ESS involves two parts: thermodynamic, in which energetic and exergetic efficiencies are considered; and economic. Within the molten salt ESS, the two-part analysis covers three major system elements: molten salt ESS designs (two tank direct and thermocline), the molten salt choice, and the different power cycles coupled with the molten salt ESS. Analysis models are formulated and analyzed to determine the most effective ESS. The results show that the most efficient idealized energy storage system is the two tank direct molten salt ESS with an Air Brayton combined cycle using LiF-NaF-KF as the molten salt, and the most economical is the same design with KCl MgCl2 as the molten salt. With energy production being a major worldwide industry, understanding the most efficient molten salt ESS boosts development of an effective NHES with cheap, clean, and steady power.« less

Watershed nitrogen and phosphorus balance: The upper Potomac River basin

DOE Office of Scientific and Technical Information (OSTI.GOV)

Jaworski, N.A.; Groffman, P.M.; Keller, A.A.

1992-01-01

Nitrogen and phosphorus mass balances were estimated for the portion of the Potomac River basin watershed located above Washington, D.C. The total nitrogen (N) balance included seven input source terms, six sinks, and one 'change-in-storage' term, but was simplified to five input terms and three output terms. The phosphorus (P) baance had four input and three output terms. The estimated balances are based on watershed data from seven information sources. Major sources of nitrogen are animal waste and atmospheric deposition. The major sources of phosphorus are animal waste and fertilizer. The major sink for nitrogen is combined denitrification, volatilization, andmore » change-in-storage. The major sink for phosphorus is change-in-storage. River exports of N and P were 17% and 8%, respectively, of the total N and P inputs. Over 60% of the N and P were volatilized or stored. The major input and output terms on the budget are estimated from direct measurements, but the change-in-storage term is calculated by difference. The factors regulating retention and storage processes are discussed and research needs are identified.« less

Maggot development during morgue storage and its effect on estimating the post-mortem interval.

PubMed

Huntington, Timothy E; Higley, Leon G; Baxendale, Frederick P

2007-03-01

When insect evidence is obtained during autopsy, forensic entomologists make decisions regarding the effects of low-temperature (-1 degrees C to 4 degrees C) storage of the body and associated insects when estimating the post-mortem interval (PMI). To determine the effects of storage in a morgue cooler on the temperature of maggot masses, temperatures inside and outside of body bags containing a human cadaver and porcine cadavers (seven replicates) were measured during storage. Temperatures remained significantly higher (p<0.05) inside of the body bags relative to the cooler, and remained at levels sufficient for maggot feeding and development. If the assumption that no insect development takes place during preautopsy refrigeration is made, potential error rates in PMI estimation of 8.6-12.8% occur. The potential for blow fly larvae to undergo significant development while being stored in the morgue is a possibility that forensic entomologists should consider during an investigation involving samples collected from autopsy. Case and experimental evidence also demonstrate that substantial tissue loss can occur from maggot feeding during morgue storage.

Land Water Storage within the Congo Basin Inferred from GRACE Satellite Gravity Data

NASA Technical Reports Server (NTRS)

Crowley, John W.; Mitrovica, Jerry X.; Bailey, Richard C.; Tamisiea, Mark E.; Davis, James L.

2006-01-01

GRACE satellite gravity data is used to estimate terrestrial (surface plus ground) water storage within the Congo Basin in Africa for the period of April, 2002 - May, 2006. These estimates exhibit significant seasonal (30 +/- 6 mm of equivalent water thickness) and long-term trends, the latter yielding a total loss of approximately 280 km(exp 3) of water over the 50-month span of data. We also combine GRACE and precipitation data set (CMAP, TRMM) to explore the relative contributions of the source term to the seasonal hydrological balance within the Congo Basin. We find that the seasonal water storage tends to saturate for anomalies greater than 30-44 mm of equivalent water thickness. Furthermore, precipitation contributed roughly three times the peak water storage after anomalously rainy seasons, in early 2003 and 2005, implying an approximately 60-70% loss from runoff and evapotranspiration. Finally, a comparison of residual land water storage (monthly estimates minus best-fitting trends) in the Congo and Amazon Basins shows an anticorrelation, in agreement with the 'see-saw' variability inferred by others from runoff data.

Energy Storage for the Power Grid

ScienceCinema

Imhoff, Carl; Vaishnav, Dave; Wang, Wei

2018-05-30

The iron vanadium redox flow battery was developed by researchers at Pacific Northwest National Laboratory as a solution to large-scale energy storage for the power grid. This technology provides the energy industry and the nation with a reliable, stable, safe, and low-cost storage alternative for a cleaner, efficient energy future.

ENERGY STAR Certified Data Center Storage

EPA Pesticide Factsheets

Certified models meet all ENERGY STAR requirements as listed in the Version 1.0 ENERGY STAR Program Requirements for Data Center Storage that are effective as of December 2, 2013. A detailed listing of key efficiency criteria are available at http://www.energystar.gov/certified-products/detail/data_center_storage

Subsurface Thermal Energy Storage for Improved Heating and Air Conditioning Efficiency

DTIC Science & Technology

2016-11-21

This project involved a field demonstration of subsurface thermal energy storage for improving the geothermal heat pump air conditioning efficiency... geothermal heat pump systems, undesirable heating of the ground may occur. This demonstration was performed at the MCAS, Beaufort, SC, where several...buildings with geothermal heat pump systems were exhibiting excessively high ground loop temperatures. These buildings were retrofitted with dry fluid

Effects of electrode settings on chlorine generation efficiency of electrolyzing seawater.

PubMed

Hsu, Guoo-Shyng Wang; Hsia, Chih-Wei; Hsu, Shun-Yao

2015-12-01

Electrolyzed water has significant disinfection effects, can comply with food safety regulations, and is environmental friendly. We investigated the effects of immersion depth of electrodes, stirring, electrode size, and electrode gap on the properties and chlorine generation efficiency of electrolyzing seawater and its storage stability. Results indicated that temperature and oxidation-reduction potential (ORP) of the seawater increased gradually, whereas electrical conductivity decreased steadily in electrolysis. During the electrolysis process, pH values and electric currents also decreased slightly within small ranges. Additional stirring or immersing the electrodes deep under the seawater significantly increased current density without affecting its electric efficiency and current efficiency. Decreasing electrode size or increasing electrode gap decreased chlorine production and electric current of the process without affecting its electric efficiency and current efficiency. Less than 35% of chlorine in the electrolyzed seawater was lost in a 3-week storage period. The decrement trend leveled off after the 1 st week of storage. The electrolyzing system is a convenient and economical method for producing high-chlorine seawater, which will have high potential applications in agriculture, aquaculture, or food processing. Copyright © 2015. Published by Elsevier B.V.

The Evolution of Root Zone Storage Capacity after Land Use Change

NASA Astrophysics Data System (ADS)

Nijzink, Remko C.; Hutton, Christopher; Pechlivanidis, Ilias; Capell, René; Arheimer, Berit; Wagener, Thorsten; Savenije, Hubert H. G.; Hrachowitz, Markus

2016-04-01

Root zone storage capacity forms a crucial parameter in ecosystem functioning as it is the key parameter that determines the partitioning between runoff and transpiration. There is increasing evidence from several case studies for specific plants that vegetation adapts to the critical situation of droughts. For example, trees will, on the long term, try to improve their internal hydraulic conductivity after droughts, for example by allocating more biomass for roots. In spite of this understanding, the water storage capacity in the root zone is often treated as constant in hydrological models. In this study, it was hypothesized that root zone storage capacities are altered by deforestation and the regrowth of the ecosystem. Three deforested sub catchments as well as not affected, nearby control catchments of the experimental forests of HJ Andrews and Hubbard Brook were selected for this purpose. Root zone storage capacities were on the one hand estimated by a climate-based approach similar to Gao et al. (2014), making use of simple water balance considerations to determine the evaporative demand of the system. In this way, the maximum deficit between evaporative demand and precipitation allows a robust estimation of the root zone storage capacity. On the other hand, three conceptual hydrological models (FLEX, HYPE, HYMOD) were calibrated in a moving window approach for all catchments. The obtained model parameter values representing the root zone storage capacities of the individual catchments for each moving window period were then compared to the estimates derived from climate data for the same periods. Model- and climate-derived estimates of root zone storage capacities both showed a similar evolution. In the deforested catchments, considerable reductions of the root zone storage capacities, compared to the pre-treatment situation and control catchments, were observed. In addition, the years after forest clearing were characterized by a gradual recovery of the root zone storage capacities, converging to new equilibrium conditions and linked to forest regrowth. Further trend analysis suggested a relatively quick hydrological recovery between 5 and 15 years in the study catchments. The results lend evidence to the role of both, climate and vegetation dynamics for the development of root zone systems and their controlling influence on hydrological response dynamics.

IV INTERNATIONAL CONFERENCE ON ATOM AND MOLECULAR PULSED LASERS (AMPL'99): Efficient long-pulse XeCl laser with a prepulse formed by an inductive energy storage device

NASA Astrophysics Data System (ADS)

Baksht, E. Kh; Panchenko, Aleksei N.; Tarasenko, Viktor F.

2000-06-01

An efficient electric-discharge XeCl laser is developed, which is pumped by a self-sustained discharge with a prepulse formed by a generator with an inductive energy storage device and a semiconductor current interrupter on a basis of semiconductor opening switch (SOS) diodes. An output energy up to 800 mJ, a pulse length up to 450 ns, and a total laser efficiency of 2.2% were attained by using spark UV preionisation.

Aquifer-storage change in the lower Canada del Oro Subbasin, Pima County, Arizona, 1996-98

USGS Publications Warehouse

Pool, D.R.

1999-01-01

Aquifer storage was monitored using gravity methods in the Lower Canada del Oro subbasin from 1996 through 1998 to determine areas of infiltration and amounts of recharge along the Canada del Oro Wash after major surface flow and to estimate aquifer-storage change and specific-yield values for the regional aquifer.  Both purposes were addressed by periodic monitoring of changes in aquifer storage and water levels at a network of gravity stations and monitor wells.  Water levels and gravity were also monitored near an active withdrawal well for several months for the purpose of estimating specific yield of the aquifer within the cone of water-leel depression at the well.

Rapid charging of thermal energy storage materials through plasmonic heating.

PubMed

Wang, Zhongyong; Tao, Peng; Liu, Yang; Xu, Hao; Ye, Qinxian; Hu, Hang; Song, Chengyi; Chen, Zhaoping; Shang, Wen; Deng, Tao

2014-09-01

Direct collection, conversion and storage of solar radiation as thermal energy are crucial to the efficient utilization of renewable solar energy and the reduction of global carbon footprint. This work reports a facile approach for rapid and efficient charging of thermal energy storage materials by the instant and intense photothermal effect of uniformly distributed plasmonic nanoparticles. Upon illumination with both green laser light and sunlight, the prepared plasmonic nanocomposites with volumetric ppm level of filler concentration demonstrated a faster heating rate, a higher heating temperature and a larger heating area than the conventional thermal diffusion based approach. With controlled dispersion, we further demonstrated that the light-to-heat conversion and thermal storage properties of the plasmonic nanocomposites can be fine-tuned by engineering the composition of the nanocomposites.

An energy efficient and high speed architecture for convolution computing based on binary resistive random access memory

NASA Astrophysics Data System (ADS)

Liu, Chen; Han, Runze; Zhou, Zheng; Huang, Peng; Liu, Lifeng; Liu, Xiaoyan; Kang, Jinfeng

2018-04-01

In this work we present a novel convolution computing architecture based on metal oxide resistive random access memory (RRAM) to process the image data stored in the RRAM arrays. The proposed image storage architecture shows performances of better speed-device consumption efficiency compared with the previous kernel storage architecture. Further we improve the architecture for a high accuracy and low power computing by utilizing the binary storage and the series resistor. For a 28 × 28 image and 10 kernels with a size of 3 × 3, compared with the previous kernel storage approach, the newly proposed architecture shows excellent performances including: 1) almost 100% accuracy within 20% LRS variation and 90% HRS variation; 2) more than 67 times speed boost; 3) 71.4% energy saving.

Rapid Charging of Thermal Energy Storage Materials through Plasmonic Heating

PubMed Central

Wang, Zhongyong; Tao, Peng; Liu, Yang; Xu, Hao; Ye, Qinxian; Hu, Hang; Song, Chengyi; Chen, Zhaoping; Shang, Wen; Deng, Tao

2014-01-01

Direct collection, conversion and storage of solar radiation as thermal energy are crucial to the efficient utilization of renewable solar energy and the reduction of global carbon footprint. This work reports a facile approach for rapid and efficient charging of thermal energy storage materials by the instant and intense photothermal effect of uniformly distributed plasmonic nanoparticles. Upon illumination with both green laser light and sunlight, the prepared plasmonic nanocomposites with volumetric ppm level of filler concentration demonstrated a faster heating rate, a higher heating temperature and a larger heating area than the conventional thermal diffusion based approach. With controlled dispersion, we further demonstrated that the light-to-heat conversion and thermal storage properties of the plasmonic nanocomposites can be fine-tuned by engineering the composition of the nanocomposites. PMID:25175717

A review of Andasol 3 and perspective for parabolic trough CSP plants in South Africa

NASA Astrophysics Data System (ADS)

Dinter, Frank; Möller, Lucas

2016-05-01

Andasol 3 is a 50 MW parabolic trough concentrating solar power plant with thermal energy storage in Andalusia, southern Spain. Having started operating in 2011 as one of the first plants of its kind in Spain it has been followed by more than 50 in the country since. For the reason that CSP plants with storage have the potential to compete against fossil fuel fired plants much better than any other renewable energy source a long-term review of such a plant operating on a commercial scale is needed. With data at hand documenting Andasol 3's operation over the course of one year between July 2013 and June 2014 we intend to provide such a review. We calculated the plants overall efficiency, its capacity factor, the gross energy generation as well as auxiliary powers on a monthly basis to reflect upon its overall performance. It was also looked at the benefits caused by the thermal energy storage and especially how steadily and reliably the plant was able to operate. With basic background information about physical, geographical and meteorological aspects influencing the solar resource, its variation and a CSP plant's performance a qualitative estimation for a parabolic trough plant located in South Africa was made.

Distinct neural markers of TVA-based visual processing speed and short-term storage capacity parameters.

PubMed

Wiegand, Iris; Töllner, Thomas; Habekost, Thomas; Dyrholm, Mads; Müller, Hermann J; Finke, Kathrin

2014-08-01

An individual's visual attentional capacity is characterized by 2 central processing resources, visual perceptual processing speed and visual short-term memory (vSTM) storage capacity. Based on Bundesen's theory of visual attention (TVA), independent estimates of these parameters can be obtained from mathematical modeling of performance in a whole report task. The framework's neural interpretation (NTVA) further suggests distinct brain mechanisms underlying these 2 functions. Using an interindividual difference approach, the present study was designed to establish the respective ERP correlates of both parameters. Participants with higher compared to participants with lower processing speed were found to show significantly reduced visual N1 responses, indicative of higher efficiency in early visual processing. By contrast, for participants with higher relative to lower vSTM storage capacity, contralateral delay activity over visual areas was enhanced while overall nonlateralized delay activity was reduced, indicating that holding (the maximum number of) items in vSTM relies on topographically specific sustained activation within the visual system. Taken together, our findings show that the 2 main aspects of visual attentional capacity are reflected in separable neurophysiological markers, validating a central assumption of NTVA. © The Author 2013. Published by Oxford University Press. All rights reserved. For Permissions, please e-mail: journals.permissions@oup.com.

Ice Age terrestrial carbon changes revisited

NASA Astrophysics Data System (ADS)

Crowley, Thomas J.

1995-09-01

N. Shackleton (1977) first proposed that changes in the marine δ13C record (Δδ13C) could be used to infer ice age changes in carbon storage on land. The previously published best estimate from the marine record is equivalent to about 490 Gt (0.32 Δδ13C). However, Adams et al. (1990) utilized a pollen database to estimate a 1350 Gt change in carbon storage, which would cause a Δδ13C of about 0.90‰. The nearly trillion ton difference in estimates amounts to almost half of the total carbon stored on land. To address the nature of this discrepancy, I have reexamined the terrestrial carbon record based on a new pollen database compiled by R. Webb and the Cooperative Holocene Mapping Project (COHMAP) group. I estimate about 750-1050 Gt glacial-interglacial change in terrestrial carbon storage, with the range reflecting uncertainties in carbon storage values for different biomes. Additional uncertainties apply to rainforest and wetland extent and presence of C4 plants, which have a significantly different isotopic signature than C3 plants. Although some scenarios overlap a new estimate of carbon storage based on the oceanic Δδ13C record (revised to 0.40‰ and 610 Gt), most estimates seem to fall outside the envelope of uncertainty in the marine record. Several possible explanations for this gap involve: (1) a missing sink may be involved in land-sea carbon exchange (e.g., continental slopes); (2) the geochemistry of the exchange process is not understood; (3) carbon storage by biome may have changed under ice age boundary conditions; or (4) the standard interpretation of whole ocean changes in the marine δ13C record requires reevaluation. This latter conclusion receives some support from comparison of the δ13C records for δ18O Stages 2 and 6. For the Stage 6 glacial, the δ13C changes are 50-60% larger than for the Stage 2 glacial. Yet implications of increased aridity are not supported by longterm trends in atmospheric dust loading. To summarize, the above analysis implies that, despite the uncertainties remaining in estimates of terrestrial carbon storage changes, a case can be made that our understanding of the transfer process is incomplete and that the eventual explanation may require clarification of factors affecting the marine δ13C record.

Implications of GRACE Satellite Gravity Measurements for Diverse Hydrological Applications

NASA Astrophysics Data System (ADS)

Yirdaw-Zeleke, Sitotaw

Soil moisture plays a major role in the hydrologic water balance and is the basis for most hydrological models. It influences the partitioning of energy and moisture inputs at the land surface. Because of its importance, it has been used as a key variable for many hydrological studies such as flood forecasting, drought studies and the determination of groundwater recharge. Therefore, spatially distributed soil moisture with reasonable temporal resolution is considered a valuable source of information for hydrological model parameterization and validation. Unfortunately, soil moisture is difficult to measure and remains essentially unmeasured over spatial and temporal scales needed for a number of hydrological model applications. In 2002, the Gravity Recovery And Climate Experiment (GRACE) satellite platform was launched to measure, among other things, the gravitational field of the earth. Over its life span, these orbiting satellites have produced time series of mass changes of the earth-atmosphere system. The subsequent outcome of this, after integration over a number of years, is a time series of highly refined images of the earth's mass distribution. In addition to quantifying the static distribution of mass, the month-to-month variation in the earth's gravitational field are indicative of the integrated value of the subsurface total water storage for specific catchments. Utilization of these natural changes in the earth's gravitational field entails the transformation of the derived GRACE geopotential spherical harmonic coefficients into spatially varying time series estimates of total water storage. These remotely sensed basin total water storage estimates can be routinely validated against independent estimates of total water storage from an atmospheric-based water balance approach or from well calibrated macroscale hydrologic models. The hydrological relevance and implications of remotely estimated GRACE total water storage over poorly gauged, wetland-dominated watershed as well as over a deltaic region underlain by a thick sand aquifer in Western Canada are the focus of this thesis. The domain of the first case study was the Mackenzie River Basin wherein the GRACE total water storage estimates were successfully inter-compared and validated with the atmospheric based water balance. These were then used to assess the WAT-CLASS hydrological model estimates of total water storage. The outcome of this inter-comparison revealed the potential application of the GRACE-based approach for the closure of the hydrological water balance of the Mackenzie River Basin as well as a dependable source of data for the calibration of traditional hydrological models. The Mackenzie River Basin result led to a second case study where the GRACE-based total water storage was validated using storage estimated from the atmospheric-based water balance P--E computations in conjunction with the measured streamflow records for the Saskatchewan River Basin at its Grand Rapids outlet in Manitoba. The fallout from this comparison was then applied to the characterization of the Prairie-wide 2002/2003 drought enabling the development of a new drought index now known as the Total Storage Deficit Index (TSDI). This study demonstrated the potential application of the GRACE-based technique as a tool for drought characterization in the Canadian Prairies. Finally, the hydroinformatic approach based on the artificial neural network (ANN) enabled the downscaling of the groundwater component from the total water storage estimate from the remote sensing satellite, GRACE. This was subsequently explored as an alternate source of calibration and validation for a hydrological modeling application over the Assiniboine Delta Aquifer in Manitoba. Interestingly, a high correlation exists between the simulated groundwater storage from the coupled hydrological model, CLM-PF and the downscaled groundwater time series storage from the remote sensing satellite GRACE over this 4,000 km2 deltaic basin in Canada.

A high-rate and long cycle life aqueous electrolyte battery for grid-scale energy storage.

PubMed

Pasta, Mauro; Wessells, Colin D; Huggins, Robert A; Cui, Yi

2012-01-01

New types of energy storage are needed in conjunction with the deployment of solar, wind and other volatile renewable energy sources and their integration with the electric grid. No existing energy storage technology can economically provide the power, cycle life and energy efficiency needed to respond to the costly short-term transients that arise from renewables and other aspects of grid operation. Here we demonstrate a new type of safe, fast, inexpensive, long-life aqueous electrolyte battery, which relies on the insertion of potassium ions into a copper hexacyanoferrate cathode and a novel activated carbon/polypyrrole hybrid anode. The cathode reacts rapidly with very little hysteresis. The hybrid anode uses an electrochemically active additive to tune its potential. This high-rate, high-efficiency cell has a 95% round-trip energy efficiency when cycled at a 5C rate, and a 79% energy efficiency at 50C. It also has zero-capacity loss after 1,000 deep-discharge cycles.

Process configuration of Liquid-nitrogen Energy Storage System (LESS) for maximum turnaround efficiency

NASA Astrophysics Data System (ADS)

Dutta, Rohan; Ghosh, Parthasarathi; Chowdhury, Kanchan

2017-12-01

Diverse power generation sector requires energy storage due to penetration of variable renewable energy sources and use of CO2 capture plants with fossil fuel based power plants. Cryogenic energy storage being large-scale, decoupled system with capability of producing large power in the range of MWs is one of the options. The drawback of these systems is low turnaround efficiencies due to liquefaction processes being highly energy intensive. In this paper, the scopes of improving the turnaround efficiency of such a plant based on liquid Nitrogen were identified and some of them were addressed. A method using multiple stages of reheat and expansion was proposed for improved turnaround efficiency from 22% to 47% using four such stages in the cycle. The novelty here is the application of reheating in a cryogenic system and utilization of waste heat for that purpose. Based on the study, process conditions for a laboratory-scale setup were determined and presented here.

Thermal Storage Applications Workshop. Volume 1: Plenary Session Analysis

NASA Technical Reports Server (NTRS)

1979-01-01

The importance of the development of inexpensive and efficient thermal and thermochemical energy storage technology to the solar power program is discussed in a summary of workship discussions held to exchange information and plan for future systems. Topics covered include storage in central power applications such as the 10 MW-e demonstration pilot receiver to be constructed in Barstow, California; storage for small dispersed systems, and problems associated with the development of storage systems for solar power plants interfacing with utility systems.

The mathematical model accuracy estimation of the oil storage tank foundation soil moistening

NASA Astrophysics Data System (ADS)

Gildebrandt, M. I.; Ivanov, R. N.; Gruzin, AV; Antropova, L. B.; Kononov, S. A.

2018-04-01

The oil storage tanks foundations preparation technologies improvement is the relevant objective which achievement will make possible to reduce the material costs and spent time for the foundation preparing while providing the required operational reliability. The laboratory research revealed the nature of sandy soil layer watering with a given amount of water. The obtained data made possible developing the sandy soil layer moistening mathematical model. The performed estimation of the oil storage tank foundation soil moistening mathematical model accuracy showed the experimental and theoretical results acceptable convergence.

Evaluating groundwater depletion as computed by a global water model

NASA Astrophysics Data System (ADS)

Schuh, Carina; Doell, Petra; Mueller Schmied, Hannes; Portmann, Felix

2013-04-01

When groundwater abstraction occurs faster than its replenishment over a long time and in a large area, the result is an overexploitation or depletion of groundwater. The problem is aggravated in areas where a growing population relies on freshwater resources for an intensive irrigation agriculture that is meant to guarantee food security. Especially in semi-arid and arid regions, the dominant use for groundwater is irrigation, reaching more than 95% of total water use. Therefore, the hot spots for groundwater depletion are the world's major irrigation areas like the central United States, north-western India and north China. Groundwater depletion presents a major threat to securing agricultural productivity and domestic water supply in these parts of the world. Besides, the environmental consequences that accompany the abstraction of groundwater are severe. Within the scientific community there is a common understanding that high-quality data on globally existing groundwater resources are deficient. In order to allow a sustainable management of the world's available groundwater resources, especially in areas under current water stress, the quantification of groundwater depletion is of high importance. WaterGAP (Water - Global Assessment and Prognosis) is a global model of water availability and water use which can serve to estimate the impact of groundwater and surface water withdrawals on groundwater storage. The new WaterGAP version 2.2a was modified to allow for an improved analysis of groundwater storage changes in semi-arid and arid regions. Now, groundwater recharge from surface water bodies is simulated in semi-arid and arid areas. Estimation of net groundwater abstractions was modified with respect of irrigation water use efficiency for groundwater and return flow fractions. In addition, irrigation consumptive use has been set to 70% of optimal irrigation consumptive use, assuming deficit irrigation to prevail in these parts of the world. Based on time series of groundwater storage as computed by WaterGAP, the yearly groundwater depletion rates for the period 1901-2009 have been determined and compared to independent estimates (well observations and GRACE satellite data). So far, the results show that the former WaterGAP standard version overestimates groundwater storage losses considerably in all of the study regions (USA, north-western India, and North China Plain) whereas the improved WaterGAP 2.2a mimics observed groundwater depletion to a high degree.

Energy storage properties and relaxor behavior of lead-free Ba1-xSm2x/3Zr0.15Ti0.85O3 ceramics.

PubMed

Sun, Zheng; Li, Lingxia; Yu, Shihui; Kang, Xinyu; Chen, Siliang

2017-10-24

Lead-free Ba 1-x Sm 2x/3 Zr 0.15 Ti 0.85 O 3 (BSZT) ceramics were synthesized by a solid state reaction route. The microstructure, dielectric relaxor behavior and energy storage properties of BSZT ceramics were studied. The growth of grain size was suppressed with the increase of Sm addition and kept in the submicrometer scale. Successive substitution of Sm 3+ for Ba 2+ disrupted the long-range dipole and promoted the increase of polar nano-region (PNR) size, resulting in the enhanced degree of relaxor behavior. The increasing PNR size also lead to the slimmer hysteresis loops and improved the energy storage efficiency. Furthermore, high saturated polarization (P max ) and low remnant polarization (P r ) were obtained due to the formation of defect dipoles, which facilitated the switch of PNRs and contributed to the enhancement of energy storage density. The x = 0.003 sample was found to exhibit a higher energy storage density of 1.15 J cm -3 and an energy storage efficiency of 92%. The result revealed that the BSZT ceramics may be a good candidate for energy storage application.

Evaluating Dihydroazulene/Vinylheptafulvene Photoswitches for Solar Energy Storage Applications

PubMed Central

Wang, Zhihang; Udmark, Jonas; Börjesson, Karl; Rodrigues, Rita; Roffey, Anna; Abrahamsson, Maria

2017-01-01

Abstract Efficient solar energy storage is a key challenge in striving toward a sustainable future. For this reason, molecules capable of solar energy storage and release through valence isomerization, for so‐called molecular solar thermal energy storage (MOST), have been investigated. Energy storage by photoconversion of the dihydroazulene/vinylheptafulvene (DHA/VHF) photothermal couple has been evaluated. The robust nature of this system is determined through multiple energy storage and release cycles at elevated temperatures in three different solvents. In a nonpolar solvent such as toluene, the DHA/VHF system can be cycled more than 70 times with less than 0.01 % degradation per cycle. Moreover, the [Cu(CH3CN)4]PF6‐catalyzed conversion of VHF into DHA was demonstrated in a flow reactor. The performance of the DHA/VHF couple was also evaluated in prototype photoconversion devices, both in the laboratory by using a flow chip under simulated sunlight and under outdoor conditions by using a parabolic mirror. Device experiments demonstrated a solar energy storage efficiency of up to 0.13 % in the chip device and up to 0.02 % in the parabolic collector. Avenues for future improvements and optimization of the system are also discussed. PMID:28644559

Smoothing-based compressed state Kalman filter for joint state-parameter estimation: Applications in reservoir characterization and CO2 storage monitoring

NASA Astrophysics Data System (ADS)

Li, Y. J.; Kokkinaki, Amalia; Darve, Eric F.; Kitanidis, Peter K.

2017-08-01

The operation of most engineered hydrogeological systems relies on simulating physical processes using numerical models with uncertain parameters and initial conditions. Predictions by such uncertain models can be greatly improved by Kalman-filter techniques that sequentially assimilate monitoring data. Each assimilation constitutes a nonlinear optimization, which is solved by linearizing an objective function about the model prediction and applying a linear correction to this prediction. However, if model parameters and initial conditions are uncertain, the optimization problem becomes strongly nonlinear and a linear correction may yield unphysical results. In this paper, we investigate the utility of one-step ahead smoothing, a variant of the traditional filtering process, to eliminate nonphysical results and reduce estimation artifacts caused by nonlinearities. We present the smoothing-based compressed state Kalman filter (sCSKF), an algorithm that combines one step ahead smoothing, in which current observations are used to correct the state and parameters one step back in time, with a nonensemble covariance compression scheme, that reduces the computational cost by efficiently exploring the high-dimensional state and parameter space. Numerical experiments show that when model parameters are uncertain and the states exhibit hyperbolic behavior with sharp fronts, as in CO2 storage applications, one-step ahead smoothing reduces overshooting errors and, by design, gives physically consistent state and parameter estimates. We compared sCSKF with commonly used data assimilation methods and showed that for the same computational cost, combining one step ahead smoothing and nonensemble compression is advantageous for real-time characterization and monitoring of large-scale hydrogeological systems with sharp moving fronts.

Project acceleration : making the leap from pilot to commercialization.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Borneo, Daniel R.

2010-05-01

Since the energy storage technology market is in a relatively emergent phase, narrowing the gap between pilot project status and commercialization is fundamental to the accelerating of this innovative market space. This session will explore regional market design factors to facilitate the storage enterprise. You will also hear about: quantifying transmission and generation efficiency enhancements; resource planning for storage; and assessing market mechanisms to accelerate storage adoption regionally.

78 FR 58535 - Hydropower Regulatory Efficiency Act of 2013; Supplemental Notice of Workshop

Federal Register 2010, 2011, 2012, 2013, 2014

2013-09-24

... license for hydropower development at non-powered dams and closed-loop pumped storage projects in... for licensing hydropower development at non-powered dams and closed-loop pumped storage projects... closed- loop pumped storage) affect the steps included in a two-year process? 3.9 Should there be a...

40 CFR 63.545 - What are my standards for fugitive dust sources?

Code of Federal Regulations, 2013 CFR

2013-07-01

.... (4) Battery storage area. (5) Equipment maintenance. (6) Material storage areas. (7) Material... achieve 99.97 percent capture efficiency for 0.3 micron particles in a manner that does not generate... 40 CFR 302.4). (4) Battery storage areas. You must inspect any batteries that are not stored in a...

40 CFR 63.545 - What are my standards for fugitive dust sources?

Code of Federal Regulations, 2012 CFR

2012-07-01

.... (4) Battery storage area. (5) Equipment maintenance. (6) Material storage areas. (7) Material... achieve 99.97 percent capture efficiency for 0.3 micron particles in a manner that does not generate... 40 CFR 302.4). (4) Battery storage areas. You must inspect any batteries that are not stored in a...

40 CFR 63.545 - What are my standards for fugitive dust sources?

Code of Federal Regulations, 2014 CFR

2014-07-01

.... (4) Battery storage area. (5) Equipment maintenance. (6) Material storage areas. (7) Material... achieve 99.97 percent capture efficiency for 0.3 micron particles in a manner that does not generate... 40 CFR 302.4). (4) Battery storage areas. You must inspect any batteries that are not stored in a...

mz5: Space- and Time-efficient Storage of Mass Spectrometry Data Sets*

PubMed Central

Wilhelm, Mathias; Kirchner, Marc; Steen, Judith A. J.; Steen, Hanno

2012-01-01

Across a host of MS-driven-omics fields, researchers witness the acquisition of ever increasing amounts of high throughput MS data and face the need for their compact yet efficiently accessible storage. Addressing the need for an open data exchange format, the Proteomics Standards Initiative and the Seattle Proteome Center at the Institute for Systems Biology independently developed the mzData and mzXML formats, respectively. In a subsequent joint effort, they defined an ontology and associated controlled vocabulary that specifies the contents of MS data files, implemented as the newer mzML format. All three formats are based on XML and are thus not particularly efficient in either storage space requirements or read/write speed. This contribution introduces mz5, a complete reimplementation of the mzML ontology that is based on the efficient, industrial strength storage backend HDF5. Compared with the current mzML standard, this strategy yields an average file size reduction to ∼54% and increases linear read and write speeds ∼3–4-fold. The format is implemented as part of the ProteoWizard project and is available under a permissive Apache license. Additional information and download links are available from http://software.steenlab.org/mz5. PMID:21960719

Evaluation of storage and evaporation in the removal efficiency of D-norgestrel and progesterone in human urine.

PubMed

Zanchetta, Priscilla Garozi; Heringer, Otávio; Scherer, Rodrigo; Pacheco, Henrique Poltronieri; Gonçalves, Ricardo; Pena, Angelina

2015-10-01

Pharmaceuticals are emerging contaminants and it must be noted that approximately 70 % of them are excreted via urine. Therefore, urine usage implies the risk of transfer of pharmaceutical residues to agricultural fields and environment contamination. Thus, this study aimed on the development and validation of a LC-MS/MS method for D-norgestrel (D-NOR) and progesterone (PRO) determination in human urine, as well as the evaluation of the removal efficiency of two methods (storage and evaporation), and the effects of acidification with sulfuric acid. The storage process was evaluated for 6 weeks, while the evaporation was assessed at three different temperatures (50, 75, and 100 °C). All experiments were done with normal urine (pH = 6.0) and acidified urine (pH = 2.0, with sulfuric acid). The results of validation showed good method efficiency. In the second week of storage, higher hormone degradation was observed. In the evaporation method, both D-NOR and PRO were almost completely degraded when the volume was reduced to the lowermost level. Results also indicate that acidification did not affect degradation. Overall, the results showed that combination of two methods can be employed for more efficient hormone removal in urine.

Estimates of Forest Biomass Carbon Storage in Liaoning Province of Northeast China: A Review and Assessment

PubMed Central

Yu, Dapao; Wang, Xiaoyu; Yin, You; Zhan, Jinyu; Lewis, Bernard J.; Tian, Jie; Bao, Ye; Zhou, Wangming; Zhou, Li; Dai, Limin

2014-01-01

Accurate estimates of forest carbon storage and changes in storage capacity are critical for scientific assessment of the effects of forest management on the role of forests as carbon sinks. Up to now, several studies reported forest biomass carbon (FBC) in Liaoning Province based on data from China's Continuous Forest Inventory, however, their accuracy were still not known. This study compared estimates of FBC in Liaoning Province derived from different methods. We found substantial variation in estimates of FBC storage for young and middle-age forests. For provincial forests with high proportions in these age classes, the continuous biomass expansion factor method (CBM) by forest type with age class is more accurate and therefore more appropriate for estimating forest biomass. Based on the above approach designed for this study, forests in Liaoning Province were found to be a carbon sink, with carbon stocks increasing from 63.0 TgC in 1980 to 120.9 TgC in 2010, reflecting an annual increase of 1.9 TgC. The average carbon density of forest biomass in the province has increased from 26.2 Mg ha−1 in 1980 to 31.0 Mg ha−1 in 2010. While the largest FBC occurred in middle-age forests, the average carbon density decreased in this age class during these three decades. The increase in forest carbon density resulted primarily from the increased area and carbon storage of mature forests. The relatively long age interval in each age class for slow-growing forest types increased the uncertainty of FBC estimates by CBM-forest type with age class, and further studies should devote more attention to the time span of age classes in establishing biomass expansion factors for use in CBM calculations. PMID:24586881

Estimates of forest biomass carbon storage inLiaoning Province of Northeast China: a review and assessment.

PubMed

Yu, Dapao; Wang, Xiaoyu; Yin, You; Zhan, Jinyu; Lewis, Bernard J; Tian, Jie; Bao, Ye; Zhou, Wangming; Zhou, Li; Dai, Limin

2014-01-01

Accurate estimates of forest carbon storage and changes in storage capacity are critical for scientific assessment of the effects of forest management on the role of forests as carbon sinks. Up to now, several studies reported forest biomass carbon (FBC) in Liaoning Province based on data from China's Continuous Forest Inventory, however, their accuracy were still not known. This study compared estimates of FBC in Liaoning Province derived from different methods. We found substantial variation in estimates of FBC storage for young and middle-age forests. For provincial forests with high proportions in these age classes, the continuous biomass expansion factor method (CBM) by forest type with age class is more accurate and therefore more appropriate for estimating forest biomass. Based on the above approach designed for this study, forests in Liaoning Province were found to be a carbon sink, with carbon stocks increasing from 63.0 TgC in 1980 to 120.9 TgC in 2010, reflecting an annual increase of 1.9 TgC. The average carbon density of forest biomass in the province has increased from 26.2 Mg ha(-1) in 1980 to 31.0 Mg ha(-1) in 2010. While the largest FBC occurred in middle-age forests, the average carbon density decreased in this age class during these three decades. The increase in forest carbon density resulted primarily from the increased area and carbon storage of mature forests. The relatively long age interval in each age class for slow-growing forest types increased the uncertainty of FBC estimates by CBM-forest type with age class, and further studies should devote more attention to the time span of age classes in establishing biomass expansion factors for use in CBM calculations.

Estimates of hydraulic properties from a one-dimensional numerical model of vertical aquifer-system deformation, Lorenzi site, Las Vegas, Nevada

USGS Publications Warehouse

Pavelko, Michael T.

2004-01-01

Land subsidence related to aquifer-system compaction and ground-water withdrawals has been occurring in Las Vegas Valley, Nevada, since the 1930's, and by the late 1980's some areas in the valley had subsided more than 5 feet. Since the late 1980's, seasonal artificial-recharge programs have lessened the effects of summertime pumping on aquifer-system compaction, but the long-term trend of compaction continues in places. Since 1994, the U.S. Geological Survey has continuously monitored water-level changes in three piezometers and vertical aquifer-system deformation with a borehole extensometer at the Lorenzi site in Las Vegas, Nevada. A one-dimensional, numerical, ground-water flow model of the aquifer system below the Lorenzi site was developed for the period 1901-2000, to estimate aquitard vertical hydraulic conductivity, aquitard inelastic skeletal specific storage, and aquitard and aquifer elastic skeletal specific storage. Aquifer water-level data were used in the model as the aquifer-system stresses that controlled simulated vertical aquifer-system deformation. Nonlinear-regression methods were used to calibrate the model, utilizing estimated and measured aquifer-system deformation data to minimize a weighted least-squares objective function, and estimate optimal property values. Model results indicate that at the Lorenzi site, aquitard vertical hydraulic conductivity is 3 x 10-6 feet per day, aquitard inelastic skeletal specific storage is 4 x 10-5 per foot, aquitard elastic skeletal specific storage is 5 x 10-6 per foot, and aquifer elastic skeletal specific storage is 3 x 10-7 per foot. Regression statistics indicate that the model and data provided sufficient information to estimate the target properties, the model adequately simulated observed data, and the estimated property values are accurate and unique.

Controlling dielectric and relaxor-ferroelectric properties for energy storage by tuning Pb0.92La0.08Zr0.52Ti0.48O3 film thickness.

PubMed

Brown, Emery; Ma, Chunrui; Acharya, Jagaran; Ma, Beihai; Wu, Judy; Li, Jun

2014-12-24

The energy storage properties of Pb0.92La0.08Zr0.52Ti0.48O3 (PLZT) films grown via pulsed laser deposition were evaluated at variable film thickness of 125, 250, 500, and 1000 nm. These films show high dielectric permittivity up to ∼1200. Cyclic I-V measurements were used to evaluate the dielectric properties of these thin films, which not only provide the total electric displacement, but also separate contributions from each of the relevant components including electric conductivity (D1), dielectric capacitance (D2), and relaxor-ferroelectric domain switching polarization (P). The results show that, as the film thickness increases, the material transits from a linear dielectric to nonlinear relaxor-ferroelectric. While the energy storage per volume increases with the film thickness, the energy storage efficiency drops from ∼80% to ∼30%. The PLZT films can be optimized for different energy storage applications by tuning the film thickness to optimize between the linear and nonlinear dielectric properties and energy storage efficiency.

Controlling Dielectric and Relaxor-Ferroelectric Properties for Energy Storage by Tuning Pb 0.92La 0.08Zr 0.52Ti 0.48O 3 Film Thickness

DOE PAGES

Brown, Emery; Ma, Chunrui; Acharya, Jagaran; ...

2014-12-24

The energy storage properties of Pb 0.92La 0.08Zr 0.52Ti 0.48O 3 (PLZT) films grown via pulsed laser deposition were evaluated at variable film thickness of 125, 250, 500, and 1000 nm. These films show high dielectric permittivity up to ~1200. Cyclic I–V measurements were used to evaluate the dielectric properties of these thin films, which not only provide the total electric displacement, but also separate contributions from each of the relevant components including electric conductivity (D1), dielectric capacitance (D2), and relaxor-ferroelectric domain switching polarization (P). Our results show that, as the film thickness increases, the material transits from a linearmore » dielectric to nonlinear relaxor-ferroelectric. And while the energy storage per volume increases with the film thickness, the energy storage efficiency drops from ~80% to ~30%. The PLZT films can be optimized for different energy storage applications by tuning the film thickness to optimize between the linear and nonlinear dielectric properties and energy storage efficiency.« less

Multi-Level Bitmap Indexes for Flash Memory Storage

DOE Office of Scientific and Technical Information (OSTI.GOV)

Wu, Kesheng; Madduri, Kamesh; Canon, Shane

2010-07-23

Due to their low access latency, high read speed, and power-efficient operation, flash memory storage devices are rapidly emerging as an attractive alternative to traditional magnetic storage devices. However, tests show that the most efficient indexing methods are not able to take advantage of the flash memory storage devices. In this paper, we present a set of multi-level bitmap indexes that can effectively take advantage of flash storage devices. These indexing methods use coarsely binned indexes to answer queries approximately, and then use finely binned indexes to refine the answers. Our new methods read significantly lower volumes of data atmore » the expense of an increased disk access count, thus taking full advantage of the improved read speed and low access latency of flash devices. To demonstrate the advantage of these new indexes, we measure their performance on a number of storage systems using a standard data warehousing benchmark called the Set Query Benchmark. We observe that multi-level strategies on flash drives are up to 3 times faster than traditional indexing strategies on magnetic disk drives.« less

Importance of storage time in mesophilic anaerobic digestion of food waste.

PubMed

Lü, Fan; Xu, Xian; Shao, Liming; He, Pinjing

2016-07-01

Storage was used as a pretreatment to enhance the methanization performance of mesophilic anaerobic digestion of food waste. Food wastes were separately stored for 0, 1, 2, 3, 4, 5, 7, and 12days, and then fed into a methanogenic reactor for a biochemical methane potential (BMP) test lasting up to 60days. Relative to the methane production of food waste stored for 0-1day (285-308mL/g-added volatile solids (VSadded)), that after 2-4days and after 5-12days of storage increased to 418-530 and 618-696mL/g-VSadded, respectively. The efficiency of hydrolysis and acidification of pre-stored food waste in the methanization reactors increased with storage time. The characteristics of stored waste suggest that methane production was not correlated with the total hydrolysis efficiency of organics in pre-stored food waste but was positively correlated with the storage time and acidification level of the waste. From the results, we recommend 5-7days of storage of food waste in anaerobic digestion treatment plants. Copyright © 2016. Published by Elsevier B.V.

Proof of cipher text ownership based on convergence encryption

NASA Astrophysics Data System (ADS)

Zhong, Weiwei; Liu, Zhusong

2017-08-01

Cloud storage systems save disk space and bandwidth through deduplication technology, but with the use of this technology has been targeted security attacks: the attacker can get the original file just use hash value to deceive the server to obtain the file ownership. In order to solve the above security problems and the different security requirements of cloud storage system files, an efficient information theory security proof of ownership scheme is proposed. This scheme protects the data through the convergence encryption method, and uses the improved block-level proof of ownership scheme, and can carry out block-level client deduplication to achieve efficient and secure cloud storage deduplication scheme.

The utility of gravity and water-level monitoring at alluvial aquifer wells in southern Arizona

USGS Publications Warehouse

Pool, D.R.

2008-01-01

Coincident monitoring of gravity and water levels at 39 wells in southern Arizona indicate that water-level change might not be a reliable indicator of aquifer-storage change for alluvial aquifer systems. One reason is that water levels in wells that are screened across single or multiple aquifers might not represent the hydraulic head and storage change in a local unconfined aquifer. Gravity estimates of aquifer-storage change can be approximated as a one-dimensional feature except near some withdrawal wells and recharge sources. The aquifer storage coefficient is estimated by the linear regression slope of storage change (estimated using gravity methods) and water-level change. Nonaquifer storage change that does not percolate to the aquifer can be significant, greater than 3 ??Gal, when water is held in the root zone during brief periods following extreme rates of precipitation. Monitor-ing of storage change using gravity methods at wells also can improve understanding of local hydrogeologic conditions. In the study area, confined aquifer conditions are likely at three wells where large water-level variations were accompanied by little gravity change. Unconfined conditions were indicated at 15 wells where significant water-level and gravity change were positively linearly correlated. Good positive linear correlations resulted in extremely large specific-yield values, greater than 0.35, at seven wells where it is likely that significant ephemeral streamflow infiltration resulted in unsaturated storage change. Poor or negative linear correlations indicate the occurrence of confined, multiple, or perched aquifers. Monitoring of a multiple compressible aquifer system at one well resulted in negative correlation of rising water levels and subsidence-corrected gravity change, which suggests that water-level trends at the well are not a good indicatior of overall storage change. ?? 2008 Society of Exploration Geophysicists. All rights reserved.

Modeling and optimization of a concentrated solar supercritical CO2 power plant

NASA Astrophysics Data System (ADS)

Osorio, Julian D.

Renewable energy sources are fundamental alternatives to supply the rising energy demand in the world and to reduce or replace fossil fuel technologies. In order to make renewable-based technologies suitable for commercial and industrial applications, two main challenges need to be solved: the design and manufacture of highly efficient devices and reliable systems to operate under intermittent energy supply conditions. In particular, power generation technologies based on solar energy are one of the most promising alternatives to supply the world energy demand and reduce the dependence on fossil fuel technologies. In this dissertation, the dynamic behavior of a Concentrated Solar Power (CSP) supercritical CO2 cycle is studied under different seasonal conditions. The system analyzed is composed of a central receiver, hot and cold thermal energy storage units, a heat exchanger, a recuperator, and multi-stage compression-expansion subsystems with intercoolers and reheaters between compressors and turbines respectively. The effects of operating and design parameters on the system performance are analyzed. Some of these parameters are the mass flow rate, intermediate pressures, number of compression-expansion stages, heat exchangers' effectiveness, multi-tank thermal energy storage, overall heat transfer coefficient between the solar receiver and the environment and the effective area of the recuperator. Energy and exergy models for each component of the system are developed to optimize operating parameters in order to lead to maximum efficiency. From the exergy analysis, the components with high contribution to exergy destruction were identified. These components, which represent an important potential of improvement, are the recuperator, the hot thermal energy storage tank and the solar receiver. Two complementary alternatives to improve the efficiency of concentrated solar thermal systems are proposed in this dissertation: the optimization of the system's operating parameters and optimization of less efficient components. The parametric optimization is developed for a 1MW reference CSP system with CO2 as the working fluid. The component optimization, focused on the less efficient components, comprises some design modifications to the traditional component configuration for the recuperator, the hot thermal energy storage tank and the solar receiver. The proposed optimization alternatives include the heat exchanger's effectiveness enhancement by optimizing fins shapes, multi-tank thermal energy storage configurations for the hot thermal energy storage tank and the incorporation of a transparent insulation material into the solar receiver. Some of the optimizations are conducted in a generalized way, using dimensionless models to be applicable no only to the CSP but also to other thermal systems. This project is therefore an effort to improve the efficiency of power generation systems based on solar energy in order to make them competitive with conventional fossil fuel power generation devices. The results show that the parametric optimization leads the system to an efficiency of about 21% and a maximum power output close to 1.5 MW. The process efficiencies obtained in this work, of more than 21%, are relatively good for a solar-thermal conversion system and are also comparable with efficiencies of conversion of high performance PV panels. The thermal energy storage allows the system to operate for several hours after sunset. This operating time is approximately increased from 220 to 480 minutes after optimization. The hot and cold thermal energy storage also lessens the temperature fluctuations by providing smooth changes of temperatures at the turbines' and compressors' inlets. Additional improvements in the overall system efficiency are possible by optimizing the less efficient components. In particular, the fin's effectiveness can be improved in more than 5% after its shape is optimized, increments in the efficiency of the thermal energy storage of about 5.7% are possible when the mass is divided into four tanks, and solar receiver efficiencies up to 70% can be maintained for high operating temperatures (~ 1200°C) when a transparent insulation material is incorporated to the receiver. The results obtained in this dissertation indicate that concentrated solar systems using supercritical CO2 could be a viable alternative to satisfying energy needs in desert areas with scarce water and fossil fuel resources.

The Role of Water in the Storage of Hydrogen in Metals

NASA Technical Reports Server (NTRS)

Hampton, Michael D.; Lomness, Janice K.; Giannuzzi, Lucille A.

2001-01-01

One major problem with the use of hydrogen is safe and efficient storage. In the pure form, bulky and heavy containers are required greatly reducing the efficiency of its use. Safety is also a great concern. Storage of hydrogen in the form of a metal hydride offers distinct advantages both in terms of volumetric efficiency and in terms of safety. As a result, an enormous amount of research is currently being done on metal-hydrogen systems. Practical application of these systems to storage of hydrogen can only occur when they are very well understood. In this paper, the preliminary results of a study of the surfaces of magnesium nickel alloys will be presented. Alloys that have been rendered totally unreactive with hydrogen as well as those that have been activated with liquid water and with water vapor were studied. Data obtained from XPS (X-ray Photoelectron Spectrometer) analysis, with samples held in vacuum for the shortest possible time to minimize the hydroxide degradation will be presented. Furthermore, TEM data on samples prepared in a new way that largely protects the surface from the high vacuum will be discussed.

Effect of storage of shelled Moringa oleifera seeds from reaping time on turbidity removal.

PubMed

Golestanbagh, M; Ahamad, I S; Idris, A; Yunus, R

2011-09-01

Moringa oleifera is an indigenous plant to Malaysia whose seeds are used for water purification. Many studies on Moringa oleifera have shown that it is highly effective as a natural coagulant for turbidity removal. In this study, two different methods for extraction of Moringa's active ingredient were investigated. Results of sodium chloride (NaCl) and distilled water extraction of Moringa oleifera seeds showed that salt solution extraction was more efficient than distilled water in extracting Moringa's active coagulant ingredient. The optimum dosage of shelled Moringa oleifera seeds extracted by the NaCl solution was comparable with that of the conventional chemical coagulant alum. Moreover, the turbidity removal efficiency was investigated for shelled Moringa oleifera seeds before drying in the oven under different storage conditions (i.e. open and closed containers at room temperature, 27 °C) and durations (fresh, and storage for 2, 4, 6 and 8 weeks from the time the seeds were picked from the trees). Our results indicate that there are no significant differences in coagulation efficiencies and, accordingly, turbidity removals between the examined storage conditions and periods.

Evaluation of relational and NoSQL database architectures to manage genomic annotations.

PubMed

Schulz, Wade L; Nelson, Brent G; Felker, Donn K; Durant, Thomas J S; Torres, Richard

2016-12-01

While the adoption of next generation sequencing has rapidly expanded, the informatics infrastructure used to manage the data generated by this technology has not kept pace. Historically, relational databases have provided much of the framework for data storage and retrieval. Newer technologies based on NoSQL architectures may provide significant advantages in storage and query efficiency, thereby reducing the cost of data management. But their relative advantage when applied to biomedical data sets, such as genetic data, has not been characterized. To this end, we compared the storage, indexing, and query efficiency of a common relational database (MySQL), a document-oriented NoSQL database (MongoDB), and a relational database with NoSQL support (PostgreSQL). When used to store genomic annotations from the dbSNP database, we found the NoSQL architectures to outperform traditional, relational models for speed of data storage, indexing, and query retrieval in nearly every operation. These findings strongly support the use of novel database technologies to improve the efficiency of data management within the biological sciences. Copyright © 2016 Elsevier Inc. All rights reserved.

An efficient, modular and simple tape archiving solution for LHC Run-3

NASA Astrophysics Data System (ADS)

Murray, S.; Bahyl, V.; Cancio, G.; Cano, E.; Kotlyar, V.; Kruse, D. F.; Leduc, J.

2017-10-01

The IT Storage group at CERN develops the software responsible for archiving to tape the custodial copy of the physics data generated by the LHC experiments. Physics run 3 will start in 2021 and will introduce two major challenges for which the tape archive software must be evolved. Firstly the software will need to make more efficient use of tape drives in order to sustain the predicted data rate of 150 petabytes per year as opposed to the current 50 petabytes per year. Secondly the software will need to be seamlessly integrated with EOS, which has become the de facto disk storage system provided by the IT Storage group for physics data. The tape storage software for LHC physics run 3 is code named CTA (the CERN Tape Archive). This paper describes how CTA will introduce a pre-emptive drive scheduler to use tape drives more efficiently, will encapsulate all tape software into a single module that will sit behind one or more EOS systems, and will be simpler by dropping support for obsolete backwards compatibility.

Reduced order models for prediction of groundwater quality impacts from CO₂ and brine leakage

DOE PAGES

Zheng, Liange; Carroll, Susan; Bianchi, Marco; ...

2014-12-31

A careful assessment of the risk associated with geologic CO₂ storage is critical to the deployment of large-scale storage projects. A potential risk is the deterioration of groundwater quality caused by the leakage of CO₂ and brine leakage from deep subsurface reservoirs. In probabilistic risk assessment studies, numerical modeling is the primary tool employed to assess risk. However, the application of traditional numerical models to fully evaluate the impact of CO₂ leakage on groundwater can be computationally complex, demanding large processing times and resources, and involving large uncertainties. As an alternative, reduced order models (ROMs) can be used as highlymore » efficient surrogates for the complex process-based numerical models. In this study, we represent the complex hydrogeological and geochemical conditions in a heterogeneous aquifer and subsequent risk by developing and using two separate ROMs. The first ROM is derived from a model that accounts for the heterogeneous flow and transport conditions in the presence of complex leakage functions for CO₂ and brine. The second ROM is obtained from models that feature similar, but simplified flow and transport conditions, and allow for a more complex representation of all relevant geochemical reactions. To quantify possible impacts to groundwater aquifers, the basic risk metric is taken as the aquifer volume in which the water quality of the aquifer may be affected by an underlying CO₂ storage project. The integration of the two ROMs provides an estimate of the impacted aquifer volume taking into account uncertainties in flow, transport and chemical conditions. These two ROMs can be linked in a comprehensive system level model for quantitative risk assessment of the deep storage reservoir, wellbore leakage, and shallow aquifer impacts to assess the collective risk of CO₂ storage projects.« less

Estimating Water Storage Capacity of Existing and Potentially Restorable Wetland Depressions in a Subbasin of the Red River of the North

USGS Publications Warehouse

Gleason, Robert A.; Tangen, Brian A.; Laubhan, Murray K.; Kermes, Kevin E.; Euliss, Ned H.

2007-01-01

Executive Summary Concern over flooding along rivers in the Prairie Pothole Region has stimulated interest in developing spatially distributed hydrologic models to simulate the effects of wetland water storage on peak river flows. Such models require spatial data on the storage volume and interception area of existing and restorable wetlands in the watershed of interest. In most cases, information on these model inputs is lacking because resolution of existing topographic maps is inadequate to estimate volume and areas of existing and restorable wetlands. Consequently, most studies have relied on wetland area to volume or interception area relationships to estimate wetland basin storage characteristics by using available surface area data obtained as a product from remotely sensed data (e.g., National Wetlands Inventory). Though application of areal input data to estimate volume and interception areas is widely used, a drawback is that there is little information available to provide guidance regarding the application, limitations, and biases associated with such approaches. Another limitation of previous modeling efforts is that water stored by wetlands within a watershed is treated as a simple lump storage component that is filled prior to routing overflow to a pour point or gaging station. This approach does not account for dynamic wetland processes that influence water stored in prairie wetlands. Further, most models have not considered the influence of human-induced hydrologic changes, such as land use, that greatly influence quantity of surface water inputs and, ultimately, the rate that a wetland basin fills and spills. The goals of this study were to (1) develop and improve methodologies for estimating and spatially depicting wetland storage volumes and interceptions areas and (2) develop models and approaches for estimating/simulating the water storage capacity of potentially restorable and existing wetlands under various restoration, land use, and climatic scenarios. To address these goals, we developed models and approaches to spatially represent storage volumes and interception areas of existing and potentially restorable wetlands in the upper Mustinka subbasin within Grant County, Minn. We then developed and applied a model to simulate wetland water storage increases that would result from restoring 25 and 50 percent of the farmed and drained wetlands in the upper Mustinka subbasin. The model simulations were performed during the growing season (May-October) for relatively wet (1993; 0.79 m of precipitation) and dry (1987; 0.40 m of precipitation) years. Results from the simulations indicated that the 25 percent restoration scenario would increase water storage by 21-24 percent and that a 50 percent scenario would increase storage by 34-38 percent. Additionally, we estimated that wetlands in the subbasin have potential to store 11.57-20.98 percent of the total precipitation that fell over the entire subbasin area (52,758 ha). Our simulation results indicated that there is considerable potential to enhance water storage in the subbasin; however, evaluation and calibration of the model is necessary before simulation results can be applied to management and planning decisions. In this report we present guidance for the development and application of models (e.g., surface area-volume predictive models, hydrology simulation model) to simulate wetland water storage to provide a basis from which to understand and predict the effects of natural or human-induced hydrologic alterations. In developing these approaches, we tried to use simple and widely available input data to simulate wetland hydrology and predict wetland water storage for a specific precipitation event or a series of events. Further, the hydrology simulation model accounted for land use and soil type, which influence surface water inputs to wetlands. Although information presented in this report is specific to the Mustinka subbasin, the approaches

Application of SPARROW modeling to understanding contaminant fate and transport from uplands to streams

USGS Publications Warehouse

Ator, Scott; Garcia, Ana Maria.

2016-01-01

Understanding spatial variability in contaminant fate and transport is critical to efficient regional water-quality restoration. An approach to capitalize on previously calibrated spatially referenced regression (SPARROW) models to improve the understanding of contaminant fate and transport was developed and applied to the case of nitrogen in the 166,000 km2 Chesapeake Bay watershed. A continuous function of four hydrogeologic, soil, and other landscape properties significant (α = 0.10) to nitrogen transport from uplands to streams was evaluated and compared among each of the more than 80,000 individual catchments (mean area, 2.1 km2) in the watershed. Budgets (including inputs, losses or net change in storage in uplands and stream corridors, and delivery to tidal waters) were also estimated for nitrogen applied to these catchments from selected upland sources. Most (81%) of such inputs are removed, retained, or otherwise processed in uplands rather than transported to surface waters. Combining SPARROW results with previous budget estimates suggests 55% of this processing is attributable to denitrification, 23% to crop or timber harvest, and 6% to volatilization. Remaining upland inputs represent a net annual increase in landscape storage in soils or biomass exceeding 10 kg per hectare in some areas. Such insights are important for planning watershed restoration and for improving future watershed models.

Final Technical Report

DOE Office of Scientific and Technical Information (OSTI.GOV)

Newmarker, Marc; Campbell, Mark

2012-03-16

Design, validate at prototype level, and then demonstrate a full size, 800 MWht Thermal Energy Storage (TES) system based on Phase Changing Material (PCM) TES modules with round trip efficiency in excess of 93%. The PCM TES module would be the building block of a TES system which can be deployed at costs inline with the DOE benchmark of 2020. The development of a reliable, unsophisticated, modular, and scalable TES system designed to be massmanufactured utilizing advanced automated fabrication and assembly processes and field installed in the most cost-effective configuration could facilitate the attainment of a Levelized Cost of Energymore » (LCOE) of $.07/kWh by 2015. It was believed that the DOE targets can be attained by finding the best combinationTES module size, its optimal integration in the power cycle, and readily available PCM. Work under this project ultimately focused on the development and performance evaluation of a 100kWht prototype heat exchanger. The design utilizes a commercially available heat exchanger product to create a unique latent heat PCM storage module. The novel ideal associated with this technology is the inclusion of an agitation mechanism that is activated during the discharge process to improve heat transfer. The prototype unit did not meet the performance goals estimated through modeling, nor did the estimated costs of the system fall in line with the goals established by DOE.« less

GRACE Hydrological estimates for small basins: Evaluating processing approaches on the High Plains Aquifer, USA

NASA Astrophysics Data System (ADS)

Longuevergne, Laurent; Scanlon, Bridget R.; Wilson, Clark R.

2010-11-01

The Gravity Recovery and Climate Experiment (GRACE) satellites provide observations of water storage variation at regional scales. However, when focusing on a region of interest, limited spatial resolution and noise contamination can cause estimation bias and spatial leakage, problems that are exacerbated as the region of interest approaches the GRACE resolution limit of a few hundred km. Reliable estimates of water storage variations in small basins require compromises between competing needs for noise suppression and spatial resolution. The objective of this study was to quantitatively investigate processing methods and their impacts on bias, leakage, GRACE noise reduction, and estimated total error, allowing solution of the trade-offs. Among the methods tested is a recently developed concentration algorithm called spatiospectral localization, which optimizes the basin shape description, taking into account limited spatial resolution. This method is particularly suited to retrieval of basin-scale water storage variations and is effective for small basins. To increase confidence in derived methods, water storage variations were calculated for both CSR (Center for Space Research) and GRGS (Groupe de Recherche de Géodésie Spatiale) GRACE products, which employ different processing strategies. The processing techniques were tested on the intensively monitored High Plains Aquifer (450,000 km2 area), where application of the appropriate optimal processing method allowed retrieval of water storage variations over a portion of the aquifer as small as ˜200,000 km2.

Landform partitioning and estimates of deep storage of soil organic matter in Zackenberg, Greenland

NASA Astrophysics Data System (ADS)

Palmtag, Juri; Cable, Stefanie; Christiansen, Hanne H.; Hugelius, Gustaf; Kuhry, Peter

2018-05-01

Soils in the northern high latitudes are a key component in the global carbon cycle, with potential feedback on climate. This study aims to improve the previous soil organic carbon (SOC) and total nitrogen (TN) storage estimates for the Zackenberg area (NE Greenland) that were based on a land cover classification (LCC) approach, by using geomorphological upscaling. In addition, novel organic carbon (OC) estimates for deeper alluvial and deltaic deposits (down to 300 cm depth) are presented. We hypothesise that landforms will better represent the long-term slope and depositional processes that result in deep SOC burial in this type of mountain permafrost environments. The updated mean SOC storage for the 0-100 cm soil depth is 4.8 kg C m-2, which is 42 % lower than the previous estimate of 8.3 kg C m-2 based on land cover upscaling. Similarly, the mean soil TN storage in the 0-100 cm depth decreased with 44 % from 0.50 kg (± 0.1 CI) to 0.28 (±0.1 CI) kg TN m-2. We ascribe the differences to a previous areal overestimate of SOC- and TN-rich vegetated land cover classes. The landform-based approach more correctly constrains the depositional areas in alluvial fans and deltas with high SOC and TN storage. These are also areas of deep carbon storage with an additional 2.4 kg C m-2 in the 100-300 cm depth interval. This research emphasises the need to consider geomorphology when assessing SOC pools in mountain permafrost landscapes.

Carbon Sequestration in Created and Natural Tidal Marshes of the Florida Panhandle

NASA Astrophysics Data System (ADS)

Rainville, K. M.; Davis, J.; Currin, C.

2016-12-01

Salt marshes are widely understood to be efficient at storing carbon in sediments (aka blue carbon) through the production of roots and rhizomes. These marshes are also able to trap sediments from incoming tides, slowly increasing their elevation over time. These qualities have led to a great deal of interest in creation and preservation of salt marshes for offsetting changes associated with anthropogenic CO2 emissions. Determinations of the value of marshes in terms of CO2 offsets requires detailed knowledge of sediment carbon storage rates, but to date, measured rates of carbon storage in created salt marsh sediments are sparse. We measured carbon storage in natural and created marshes along the Northern Gulf Coast of Florida. The created marshes were in `living shoreline' projects and ranged in age from 8 to 28 years. Dominant plant cover of the marshes included Spartina alterniflora and Juncus spp. At all sites, sediment cores (22-75 cm in depth) were collected, extruded in 5 cm increments, and carbon content was determined by elemental analysis. Measured C storage rates in the created marshes ranged from 60 to 130 g C m-2 yr-1 and decreased with marsh age. A decrease in storage rates over time is evidence of continued decomposition of stored carbon as sediments age, an important factor to consider when estimating the value of a given marsh for CO2 offsets. The rates measured in Florida are well below previously published average values ( 200 g m-2 yr-1) and also below the default value allowed for carbon crediting through the verified carbon standard (146 g m-2 yr), but similar to those measured in created marshes in North Carolina. In addition, factors such as dominant plant type, water inundation, temperature, latitude, biological belowground activity and biomass values can impact carbon storage rates of marshes among geographically distinct regions. This makes it especially important to determine carbon storage rates on a local scale, and not following a verified carbon standard. These data add to the geographic coverage over which documented C storage rates are currently available and suggest that locally determined rates are necessary for accurate carbon accounting.

A framework for streamflow prediction in the world's most severely data-limited regions: Test of applicability and performance in a poorly-gauged region of China

NASA Astrophysics Data System (ADS)

Alipour, M. H.; Kibler, Kelly M.

2018-02-01

A framework methodology is proposed for streamflow prediction in poorly-gauged rivers located within large-scale regions of sparse hydrometeorologic observation. A multi-criteria model evaluation is developed to select models that balance runoff efficiency with selection of accurate parameter values. Sparse observed data are supplemented by uncertain or low-resolution information, incorporated as 'soft' data, to estimate parameter values a priori. Model performance is tested in two catchments within a data-poor region of southwestern China, and results are compared to models selected using alternative calibration methods. While all models perform consistently with respect to runoff efficiency (NSE range of 0.67-0.78), models selected using the proposed multi-objective method may incorporate more representative parameter values than those selected by traditional calibration. Notably, parameter values estimated by the proposed method resonate with direct estimates of catchment subsurface storage capacity (parameter residuals of 20 and 61 mm for maximum soil moisture capacity (Cmax), and 0.91 and 0.48 for soil moisture distribution shape factor (B); where a parameter residual is equal to the centroid of a soft parameter value minus the calibrated parameter value). A model more traditionally calibrated to observed data only (single-objective model) estimates a much lower soil moisture capacity (residuals of Cmax = 475 and 518 mm and B = 1.24 and 0.7). A constrained single-objective model also underestimates maximum soil moisture capacity relative to a priori estimates (residuals of Cmax = 246 and 289 mm). The proposed method may allow managers to more confidently transfer calibrated models to ungauged catchments for streamflow predictions, even in the world's most data-limited regions.

Semantics-based distributed I/O with the ParaMEDIC framework.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Balaji, P.; Feng, W.; Lin, H.

2008-01-01

Many large-scale applications simultaneously rely on multiple resources for efficient execution. For example, such applications may require both large compute and storage resources; however, very few supercomputing centers can provide large quantities of both. Thus, data generated at the compute site oftentimes has to be moved to a remote storage site for either storage or visualization and analysis. Clearly, this is not an efficient model, especially when the two sites are distributed over a wide-area network. Thus, we present a framework called 'ParaMEDIC: Parallel Metadata Environment for Distributed I/O and Computing' which uses application-specific semantic information to convert the generatedmore » data to orders-of-magnitude smaller metadata at the compute site, transfer the metadata to the storage site, and re-process the metadata at the storage site to regenerate the output. Specifically, ParaMEDIC trades a small amount of additional computation (in the form of data post-processing) for a potentially significant reduction in data that needs to be transferred in distributed environments.« less

Estimating probabilities of reservoir storage for the upper Delaware River basin

USGS Publications Warehouse

Hirsch, Robert M.

1981-01-01

A technique for estimating conditional probabilities of reservoir system storage is described and applied to the upper Delaware River Basin. The results indicate that there is a 73 percent probability that the three major New York City reservoirs (Pepacton, Cannonsville, and Neversink) would be full by June 1, 1981, and only a 9 percent probability that storage would return to the ' drought warning ' sector of the operations curve sometime in the next year. In contrast, if restrictions are lifted and there is an immediate return to normal operating policies, the probability of the reservoir system being full by June 1 is 37 percent and the probability that storage would return to the ' drought warning ' sector in the next year is 30 percent. (USGS)

Using Rising Limb Analysis to Estimate Uptake of Reactive Solutes in Advective and Transient Storage Sub-compartments of Stream Ecosystems

NASA Astrophysics Data System (ADS)

Thomas, S. A.; Valett, H.; Webster, J. R.; Mulholland, P. J.; Dahm, C. N.

2001-12-01

Identifying the locations and controls governing solute uptake is a recent area of focus in studies of stream biogeochemistry. We introduce a technique, rising limb analysis (RLA), to estimate areal nitrate uptake in the advective and transient storage (TS) zones of streams. RLA is an inverse approach that combines nutrient spiraling and transient storage modeling to calculate total uptake of reactive solutes and the fraction of uptake occurring within the advective sub-compartment of streams. The contribution of the transient storage zones to solute loss is determined by difference. Twelve-hour coinjections of conservative (Cl-) and reactive (15NO3) tracers were conducted seasonally in several headwater streams among which AS/A ranged from 0.01 - 2.0. TS characteristics were determined using an advection-dispersion model modified to include hydrologic exchange with a transient storage compartment. Whole-system uptake was determined by fitting the longitudinal pattern of NO3 to first-order, exponential decay model. Uptake in the advective sub-compartment was determined by collecting a temporal sequence of samples from a single location beginning with the arrival of the solute front and concluding with the onset of plateau conditions (i.e. the rising limb). Across the rising limb, 15NO3:Cl was regressed against the percentage of water that had resided in the transient storage zone (calculated from the TS modeling). The y-intercept thus provides an estimate of the plateau 15NO3:Cl ratio in the absence of NO3 uptake within the transient storage zone. Algebraic expressions were used to calculate the percentage of NO3 uptake occurring in the advective and transient storage sub-compartments. Application of RLA successfully estimated uptake coefficients for NO3 in the subsurface when the physical dimensions of that habitat were substantial (AS/A > 0.2) and when plateau conditions at the sampling location consisted of waters in which at least 25% had resided in the transient storage zone. In those cases, the TS zone accounted for 8 - 47 % of overall NO3 uptake and uptake rates within the subsurface ranged from 0.7 - 14.3 mg N m-2 d-1.

A hyperspectral approach to estimating biomass and plant production in a heterogeneous restored temperate peatland

NASA Astrophysics Data System (ADS)

Byrd, K. B.; Schile, L. M.; Windham-Myers, L.; Kelly, M.; Hatala, J.; Baldocchi, D. D.

2012-12-01

Restoration of drained peatlands that are managed to reverse subsidence through organic accretion holds significant potential for large-scale carbon storage and sequestration. This potential has been demonstrated in an experimental wetland restoration site established by the U.S. Geological Survey in 1997 on Twitchell Island in the Sacramento-San Joaquin River Delta, where soil carbon storage is up to 1 kg C m-2 and root and rhizome production can reach over 7 kg m-2 annually. Remote sensing-based estimation of biomass and productivity over a large spatial extent helps to monitor carbon storage potential of these restored peatlands. Extensive field measurements of plant biophysical characteristics such as biomass, leaf area index, and the fraction of absorbed photosynthetically active radiation (fAPAR) [an important variable in light-use efficiency (LUE) models] have been collected for agricultural systems and forests. However the small size and local spatial variability of U.S. Pacific Coast wetlands pose new challenges for measuring these variables in the field and generating estimates through remote sensing. In particular background effects of non-photosynthetic vegetation (NPV), floating aquatic vegetation, and inundation of wetland vegetation influence the relationship between field measurements and multispectral or hyperspectral indices. Working at the USGS experimental wetland site, characterized by variable water depth and substantial NPV, or thatch, we collected field data on hardstem bulrush (Schoenoplectus acutus) and cattail (Typha spp.) coupled with reflectance data from a field spectrometer (350-2500 nm) every two to three weeks during the summers of 2011 and 2012. We calculated aboveground biomass with existing allometric relationships, and fAPAR was measured with line and point quantum sensors. We analyzed reflectance data to develop hyperspectral and multispectral indices that predict biomass and fAPAR and account for background effects of water inundation and NPV. fAPAR values were combined with GPP estimates at the field scale from eddy correlation flux measurements to develop a LUE model of plant production. To compare the effectiveness of broadband vs. narrowband indices in predicting biomass and fAPAR, we simulated eight multispectral World View-2 (WV-2) bands and 164 hyperspectral Hyperion bands with the field spectroradiometer data. We calculated NDVI-type two band vegetation indices (TBVI) using all possible band combinations, with a total of 28 WV-2 indices and 13,366 Hyperion indices. Biomass estimation was affected by water depth; regression of cattail biomass to TBVI680,910 produced a R2 that was 47% higher (R2 = 0.53) when water levels were under 50 cm compared to when water levels were over 50 cm (R2 = 0.28). fAPAR estimation was affected by the density of NPV; regression of fAPAR to TBVI539,1114 when PARtransmitted was measured above thatch was 49% higher (R2 = 0.50) than when PARtransmitted was measured below thatch (R2 = 0.20, TBVI1286,1266). Accounting for background effects in this heterogeneous environment will aid in the development of robust indices that can be applied to other wetland sites for estimates of carbon storage potential across large extents.

A method for examining the geospatial distribution of CO2 storage resources applied to the Pre-Punta Gorda Composite and Dollar Bay reservoirs of the South Florida Basin, U.S.A

USGS Publications Warehouse

Roberts-Ashby, Tina; Brandon N. Ashby,

2016-01-01

This paper demonstrates geospatial modification of the USGS methodology for assessing geologic CO2 storage resources, and was applied to the Pre-Punta Gorda Composite and Dollar Bay reservoirs of the South Florida Basin. The study provides detailed evaluation of porous intervals within these reservoirs and utilizes GIS to evaluate the potential spatial distribution of reservoir parameters and volume of CO2 that can be stored. This study also shows that incorporating spatial variation of parameters using detailed and robust datasets may improve estimates of storage resources when compared to applying uniform values across the study area derived from small datasets, like many assessment methodologies. Geospatially derived estimates of storage resources presented here (Pre-Punta Gorda Composite = 105,570 MtCO2; Dollar Bay = 24,760 MtCO2) were greater than previous assessments, which was largely attributed to the fact that detailed evaluation of these reservoirs resulted in higher estimates of porosity and net-porous thickness, and areas of high porosity and thick net-porous intervals were incorporated into the model, likely increasing the calculated volume of storage space available for CO2 sequestration. The geospatial method for evaluating CO2 storage resources also provides the ability to identify areas that potentially contain higher volumes of storage resources, as well as areas that might be less favorable.

Cost and size estimates for an electrochemical bulk energy storage concept

NASA Technical Reports Server (NTRS)

Warshay, M.; Wright, L. O.

1975-01-01

Preliminary capital cost and size estimates were made for a titanium trichloride, titanium tetrachloride, ferric chloride, ferrous chloride redox-flow-cell electric power system. On the basis of these preliminary estimates plus other important considerations, this electrochemical system emerged as having great promise as a bulk energy storage system for power load leveling. The size of this system is less than two per cent of that of a comparable pumped hydroelectric plant. The estimated capital cost of a 10 MW, 60- and 85-MWh redox-flow system compared well with that of competing systems.

Estimates of air emissions from asphalt storage tanks and truck loading

DOE Office of Scientific and Technical Information (OSTI.GOV)

Trumbore, D.C.

1999-12-31

Title V of the 1990 Clean Air Act requires the accurate estimation of emissions from all US manufacturing processes, and places the burden of proof for that estimate on the process owner. This paper is published as a tool to assist in the estimation of air emission from hot asphalt storage tanks and asphalt truck loading operations. Data are presented on asphalt vapor pressure, vapor molecular weight, and the emission split between volatile organic compounds and particulate emissions that can be used with AP-42 calculation techniques to estimate air emissions from asphalt storage tanks and truck loading operations. Since currentmore » AP-42 techniques are not valid in asphalt tanks with active fume removal, a different technique for estimation of air emissions in those tanks, based on direct measurement of vapor space combustible gas content, is proposed. Likewise, since AP-42 does not address carbon monoxide or hydrogen sulfide emissions that are known to be present in asphalt operations, this paper proposes techniques for estimation of those emissions. Finally, data are presented on the effectiveness of fiber bed filters in reducing air emissions in asphalt operations.« less

Rapid assessment of U.S. forest and soil organic carbon storage and forest biomass carbon-sequestration capacity

USGS Publications Warehouse

Sundquist, Eric T.; Ackerman, Katherine V.; Bliss, Norman B.; Kellndorfer, Josef M.; Reeves, Matt C.; Rollins, Matthew G.

2009-01-01

This report provides results of a rapid assessment of biological carbon stocks and forest biomass carbon sequestration capacity in the conterminous United States. Maps available from the U.S. Department of Agriculture are used to calculate estimates of current organic carbon storage in soils (73 petagrams of carbon, or PgC) and forest biomass (17 PgC). Of these totals, 3.5 PgC of soil organic carbon and 0.8 PgC of forest biomass carbon occur on lands managed by the U.S. Department of the Interior (DOI). Maps of potential vegetation are used to estimate hypothetical forest biomass carbon sequestration capacities that are 3–7 PgC higher than current forest biomass carbon storage in the conterminous United States. Most of the estimated hypothetical additional forest biomass carbon sequestration capacity is accrued in areas currently occupied by agriculture and development. Hypothetical forest biomass carbon sequestration capacities calculated for existing forests and woodlands are within ±1 PgC of estimated current forest biomass carbon storage. Hypothetical forest biomass sequestration capacities on lands managed by the DOI in the conterminous United States are 0–0.4 PgC higher than existing forest biomass carbon storage. Implications for forest and other land management practices are not considered in this report. Uncertainties in the values reported here are large and difficult to quantify, particularly for hypothetical carbon sequestration capacities. Nevertheless, this rapid assessment helps to frame policy and management discussion by providing estimates that can be compared to amounts necessary to reduce predicted future atmospheric carbon dioxide levels.

[Study on the quantitative estimation method for VOCs emission from petrochemical storage tanks based on tanks 4.0.9d model].

PubMed

Li, Jing; Wang, Min-Yan; Zhang, Jian; He, Wan-Qing; Nie, Lei; Shao, Xia

2013-12-01

VOCs emission from petrochemical storage tanks is one of the important emission sources in the petrochemical industry. In order to find out the VOCs emission amount of petrochemical storage tanks, Tanks 4.0.9d model is utilized to calculate the VOCs emission from different kinds of storage tanks. VOCs emissions from a horizontal tank, a vertical fixed roof tank, an internal floating roof tank and an external floating roof tank were calculated as an example. The consideration of the site meteorological information, the sealing information, the tank content information and unit conversion by using Tanks 4.0.9d model in China was also discussed. Tanks 4.0.9d model can be used to estimate VOCs emissions from petrochemical storage tanks in China as a simple and highly accurate method.

CARBON STORAGE AND FLUXES IN PONDEROSA PINE AT DIFFERENT SUCCESSIONAL STAGES

EPA Science Inventory

We compared carbon storage and fluxes in young and old ponderosa pine stands in Oregon, including plant and soil storage, net primary productivity, respiration fluxes, and eddy flux estimates of net ecosystem exchange. The young site (Y site) was previously an old-growth pondero...

High-Level Radioactive Waste: Safe Storage and Ultimate Disposal.

ERIC Educational Resources Information Center

Dukert, Joseph M.

Described are problems and techniques for safe disposal of radioactive waste. Degrees of radioactivity, temporary storage, and long-term permanent storage are discussed. Included are diagrams of estimated waste volumes to the year 2000 and of an artist's conception of a permanent underground disposal facility. (SL)

The evolution of root-zone moisture capacities after deforestation: a step towards hydrological predictions under change?

NASA Astrophysics Data System (ADS)

Nijzink, Remko; Hutton, Christopher; Pechlivanidis, Ilias; Capell, René; Arheimer, Berit; Freer, Jim; Han, Dawei; Wagener, Thorsten; McGuire, Kevin; Savenije, Hubert; Hrachowitz, Markus

2016-12-01

The core component of many hydrological systems, the moisture storage capacity available to vegetation, is impossible to observe directly at the catchment scale and is typically treated as a calibration parameter or obtained from a priori available soil characteristics combined with estimates of rooting depth. Often this parameter is considered to remain constant in time. Using long-term data (30-40 years) from three experimental catchments that underwent significant land cover change, we tested the hypotheses that: (1) the root-zone storage capacity significantly changes after deforestation, (2) changes in the root-zone storage capacity can to a large extent explain post-treatment changes to the hydrological regimes and that (3) a time-dynamic formulation of the root-zone storage can improve the performance of a hydrological model.A recently introduced method to estimate catchment-scale root-zone storage capacities based on climate data (i.e. observed rainfall and an estimate of transpiration) was used to reproduce the temporal evolution of root-zone storage capacity under change. Briefly, the maximum deficit that arises from the difference between cumulative daily precipitation and transpiration can be considered as a proxy for root-zone storage capacity. This value was compared to the value obtained from four different conceptual hydrological models that were calibrated for consecutive 2-year windows.It was found that water-balance-derived root-zone storage capacities were similar to the values obtained from calibration of the hydrological models. A sharp decline in root-zone storage capacity was observed after deforestation, followed by a gradual recovery, for two of the three catchments. Trend analysis suggested hydrological recovery periods between 5 and 13 years after deforestation. In a proof-of-concept analysis, one of the hydrological models was adapted to allow dynamically changing root-zone storage capacities, following the observed changes due to deforestation. Although the overall performance of the modified model did not considerably change, in 51 % of all the evaluated hydrological signatures, considering all three catchments, improvements were observed when adding a time-variant representation of the root-zone storage to the model.In summary, it is shown that root-zone moisture storage capacities can be highly affected by deforestation and climatic influences and that a simple method exclusively based on climate data can not only provide robust, catchment-scale estimates of this critical parameter, but also reflect its time-dynamic behaviour after deforestation.

Urban forest biomass estimates: is it important to use allometric relationships developed specifically for urban trees? 

Treesearch

M.R. McHale; I.C. Burke; M.A. Lefsky; P.J. Peper; E.G. McPherson

2009-01-01

Many studies have analyzed the benefits, costs, and carbon storage capacity associated with urban trees. These studies have been limited by a lack of research on urban tree biomass, such that estimates of carbon storage in urban systems have relied upon allometric relationships developed in traditional forests. As urbanization increases globally, it is becoming...

Novel bamboo structured TiO2 nanotubes for energy storage/production applications

NASA Astrophysics Data System (ADS)

Samuel, J. J.; Beh, K. P.; Cheong, Y. L.; Yusuf, W. A. A.; Yam, F. K.

2018-04-01

Nanostructured TiO2 received much attention owing to its high surface-to-volume ratio, which can be advantageous in energy storage and production applications. However, the increase in energy consumption at present and possibly the foreseeable future has demanded energy storage and production devices of even higher performance. A direct approach would be manipulating the physical aspects of TiO2 nanostructures, particularly, nanotubes. In this work, dual voltage anodization system has been implemented to fabricate bamboo shaped TiO2 nanotubes, which offers even greater surface area. This unique nanostructure would be used in Dye Sensitized Solar Cell (DSSC) fabrication and its performance will be evaluated and compared along other forms of TiO2 nanotubes. The results showed that bamboo shaped nanotubes indeed are superior morphologically, with an increase of efficiency of 107% at 1.130% efficiency when compared to smooth walled nanotubes at 0.546% efficiency.

High Storage Efficiency and Large Fractional Delay of EIT-Based Memory

NASA Astrophysics Data System (ADS)

Chen, Yi-Hsin; Lee, Meng-Jung; Wang, I.-Chung; Du, Shengwang; Chen, Yong-Fan; Chen, Ying-Cheng; Yu, Ite

2013-05-01

In long-distance quantum communication and optical quantum computation, an efficient and long-lived quantum memory is an important component. We first experimentally demonstrated that a time-space-reversing method plus the optimum pulse shape can improve the storage efficiency (SE) of light pulses to 78% in cold media based on the effect of electromagnetically induced transparency (EIT). We obtain a large fractional delay of 74 at 50% SE, which is the best record so far. The measured classical fidelity of the recalled pulse is higher than 90% and nearly independent of the storage time, implying that the optical memory maintains excellent phase coherence. Our results suggest the current result may be readily applied to single-photon quantum states due to quantum nature of the EIT light-matter inference. This study advances the EIT-based quantum memory in practical quantum information applications.

A novel iron-lead redox flow battery for large-scale energy storage

NASA Astrophysics Data System (ADS)

Zeng, Y. K.; Zhao, T. S.; Zhou, X. L.; Wei, L.; Ren, Y. X.

2017-04-01

The redox flow battery (RFB) is one of the most promising large-scale energy storage technologies for the massive utilization of intermittent renewables especially wind and solar energy. This work presents a novel redox flow battery that utilizes inexpensive and abundant Fe(II)/Fe(III) and Pb/Pb(II) redox couples as redox materials. Experimental results show that both the Fe(II)/Fe(III) and Pb/Pb(II) redox couples have fast electrochemical kinetics in methanesulfonic acid, and that the coulombic efficiency and energy efficiency of the battery are, respectively, as high as 96.2% and 86.2% at 40 mA cm-2. Furthermore, the battery exhibits stable performance in terms of efficiencies and discharge capacities during the cycle test. The inexpensive redox materials, fast electrochemical kinetics and stable cycle performance make the present battery a promising candidate for large-scale energy storage applications.

Matt Rogers on AES Energy Storage

ScienceCinema

Rogers, Matt

2017-12-29

The Department of Energy and AES Energy Storage recently agreed to a $17.1M conditional loan guarantee commitment. This project will develop the first battery-based energy storage system to provide a more stable and efficient electrical grid for New York State's high-voltage transmission network. Matt Rogers is the Senior Advisor to the Secretary for Recovery Act Implementation.

78 FR 62322 - Hydropower Regulatory Efficiency Act of 2013; Notice of Rescheduled Two-Year Licensing Process...

Federal Register 2010, 2011, 2012, 2013, 2014

2013-10-16

... at non-powered dams and closed-loop pumped storage projects in compliance with section 6 of the... process for licensing hydropower development at non-powered dams and closed-loop pumped storage projects...-powered dam versus closed- loop pumped storage) affect the steps included in a two-year process? 3.9...

Matt Rogers on AES Energy Storage

DOE Office of Scientific and Technical Information (OSTI.GOV)

Rogers, Matt

2010-08-02

The Department of Energy and AES Energy Storage recently agreed to a $17.1M conditional loan guarantee commitment. This project will develop the first battery-based energy storage system to provide a more stable and efficient electrical grid for New York State's high-voltage transmission network. Matt Rogers is the Senior Advisor to the Secretary for Recovery Act Implementation.

Radiolysis Model Sensitivity Analysis for a Used Fuel Storage Canister

DOE Office of Scientific and Technical Information (OSTI.GOV)

Wittman, Richard S.

2013-09-20

This report fulfills the M3 milestone (M3FT-13PN0810027) to report on a radiolysis computer model analysis that estimates the generation of radiolytic products for a storage canister. The analysis considers radiolysis outside storage canister walls and within the canister fill gas over a possible 300-year lifetime. Previous work relied on estimates based directly on a water radiolysis G-value. This work also includes that effect with the addition of coupled kinetics for 111 reactions for 40 gas species to account for radiolytic-induced chemistry, which includes water recombination and reactions with air.

Evaluation of thermal energy storage for the proposed Twin Cities District Heating system. [using cogeneration heat production and aquifiers for heat storage

NASA Technical Reports Server (NTRS)

Meyer, C. F.

1980-01-01

The technical and economic feasibility of incorporating thermal energy storage components into the proposed Twin Cities District heating project was evaluated. The technical status of the project is reviewed and conceptual designs of district heating systems with and without thermal energy storage were compared in terms of estimated capital requirements, fuel consumption, delivered energy cost, and environmental aspects. The thermal energy storage system is based on cogeneration and the storage of heat in aquifers.

Ecosystem carbon storage and flux in upland/peatland watersheds in northern Minnesota. Chapter 9.

Treesearch

David F. Grigal; Peter C. Bates; Randall K. Kolka

2011-01-01

Carbon (C) storage and fluxes (inputs and outputs of C per unit time) are central issues in global change. Spatial patterns of C storage on the landscape, both that in soil and in biomass, are important from an inventory perspective and for understanding the biophysical processes that affect C fluxes. Regional and national estimates of C storage are uncertain because...

Electricity storage using a thermal storage scheme

NASA Astrophysics Data System (ADS)

White, Alexander

2015-01-01

The increasing use of renewable energy technologies for electricity generation, many of which have an unpredictably intermittent nature, will inevitably lead to a greater demand for large-scale electricity storage schemes. For example, the expanding fraction of electricity produced by wind turbines will require either backup or storage capacity to cover extended periods of wind lull. This paper describes a recently proposed storage scheme, referred to here as Pumped Thermal Storage (PTS), and which is based on "sensible heat" storage in large thermal reservoirs. During the charging phase, the system effectively operates as a high temperature-ratio heat pump, extracting heat from a cold reservoir and delivering heat to a hot one. In the discharge phase the processes are reversed and it operates as a heat engine. The round-trip efficiency is limited only by process irreversibilities (as opposed to Second Law limitations on the coefficient of performance and the thermal efficiency of the heat pump and heat engine respectively). PTS is currently being developed in both France and England. In both cases, the schemes operate on the Joule-Brayton (gas turbine) cycle, using argon as the working fluid. However, the French scheme proposes the use of turbomachinery for compression and expansion, whereas for that being developed in England reciprocating devices are proposed. The current paper focuses on the impact of the various process irreversibilities on the thermodynamic round-trip efficiency of the scheme. Consideration is given to compression and expansion losses and pressure losses (in pipe-work, valves and thermal reservoirs); heat transfer related irreversibility in the thermal reservoirs is discussed but not included in the analysis. Results are presented demonstrating how the various loss parameters and operating conditions influence the overall performance.

The Potential of Energy Storage Systems with Respect to Generation Adequacy and Economic Viability

NASA Astrophysics Data System (ADS)

Bradbury, Kyle Joseph

Intermittent energy resources, including wind and solar power, continue to be rapidly added to the generation fleet domestically and abroad. The variable power of these resources introduces new levels of stochasticity into electric interconnections that must be continuously balanced in order to maintain system reliability. Energy storage systems (ESSs) offer one potential option to compensate for the intermittency of renewables. ESSs for long-term storage (1-hour or greater), aside from a few pumped hydroelectric installations, are not presently in widespread use in the U.S. The deployment of ESSs would be most likely driven by either the potential for a strong internal rate of return (IRR) on investment and through significant benefits to system reliability that independent system operators (ISOs) could incentivize. To assess the potential of ESSs three objectives are addressed. (1) Evaluate the economic viability of energy storage for price arbitrage in real-time energy markets and determine system cost improvements for ESSs to become attractive investments. (2) Estimate the reliability impact of energy storage systems on the large-scale integration of intermittent generation. (3) Analyze the economic, environmental, and reliability tradeoffs associated with using energy storage in conjunction with stochastic generation. First, using real-time energy market price data from seven markets across the U.S. and the physical parameters of fourteen ESS technologies, the maximum potential IRR of each technology from price arbitrage was evaluated in each market, along with the optimal ESS system size. Additionally, the reductions in capital cost needed to achieve a 10% IRR were estimated for each ESS. The results indicate that the profit-maximizing size of an ESS is primarily determined by its technological characteristics (round-trip charge/discharge efficiency and self-discharge) and not market price volatility, which instead increases IRR. This analysis demonstrates that few ESS technologies are likely to be implemented by investors alone. Next, the effects of ESSs on system reliability are quantified. Using historic data for wind, solar, and conventional generation, a correlation-preserving, copula-transform model was implemented in conjunction with Markov chain Monte Carlo framework for estimating system reliability indices. Systems with significant wind and solar penetration (25% or greater), even with added energy storage capacity, resulted in considerable decreases in generation adequacy. Lastly, rather than analyzing the reliability and costs in isolation of one another, system reliability, cost, and emissions were analyzed in 3-space to quantify and visualize the system tradeoffs. The modeling results implied that ESSs perform similarly to natural gas combined cycle (NGCC) systems with respect to generation adequacy and system cost, with the primary difference being that the generation adequacy improvements are less for ESSs than that of NGCC systems and the increase in LCOE is greater for ESSs than NGCC systems. Although ESSs do not appear to offer greater benefits than NGCC systems for managing energy on time intervals of 1-hour or more, we conclude that future research into short-term power balancing applications of ESSs, in particular for frequency regulation, is necessary to understand the full potential of ESSs in modern electric interconnections.

Dynamics of heat storage in evapotranspiration estimate

USDA-ARS?s Scientific Manuscript database

One of the widely discussed reasons for a lack of surface energy balance closure when using eddy covariance is neglect of storage term elements. Storage as related to the surface energy balance refers to all heat stored below the observation level of eddies. It represents the sum of several componen...

A body composition model to estimate mammalian energy stores and metabolic rates from body mass and body length, with application to polar bears.

PubMed

Molnár, Péter K; Klanjscek, Tin; Derocher, Andrew E; Obbard, Martyn E; Lewis, Mark A

2009-08-01

Many species experience large fluctuations in food availability and depend on energy from fat and protein stores for survival, reproduction and growth. Body condition and, more specifically, energy stores thus constitute key variables in the life history of many species. Several indices exist to quantify body condition but none can provide the amount of stored energy. To estimate energy stores in mammals, we propose a body composition model that differentiates between structure and storage of an animal. We develop and parameterize the model specifically for polar bears (Ursus maritimus Phipps) but all concepts are general and the model could be easily adapted to other mammals. The model provides predictive equations to estimate structural mass, storage mass and storage energy from an appropriately chosen measure of body length and total body mass. The model also provides a means to estimate basal metabolic rates from body length and consecutive measurements of total body mass. Model estimates of body composition, structural mass, storage mass and energy density of 970 polar bears from Hudson Bay were consistent with the life history and physiology of polar bears. Metabolic rate estimates of fasting adult males derived from the body composition model corresponded closely to theoretically expected and experimentally measured metabolic rates. Our method is simple, non-invasive and provides considerably more information on the energetic status of individuals than currently available methods.

Technical and economic assessments of storage techniques for long-term retention of industrial-beet sugar for non-food industrial fermentations

NASA Astrophysics Data System (ADS)

Vargas-Ramirez, Juan Manuel

Industrial beets may compete against corn grain as an important source of sugars for non-food industrial fermentations. However, dependable and energy-efficient systems for beet sugar storage and processing are necessary to help establish industrial beets as a viable sugar feedstock. Therefore, technical and economic aspects of beet sugar storage and processing were evaluated. First, sugar retention was evaluated in whole beets treated externally with either one of two antimicrobials or a senescence inhibitor and stored for 36 wk at different temperature and atmosphere combinations. Although surface treatment did not improve sugar retention, full retention was enabled by beet dehydration caused by ambient air at 25 °C and with a relative humidity of 37%. This insight led to the evaluation of sugar retention in ground-beet tissue ensiled for 8 wk at different combinations of acidic pH, moisture content (MC), and sugar:solids. Some combinations of pH ≤ 4.0 and MC ≤ 67.5% enabled retentions of at least 90%. Yeast fermentability was also evaluated in non-purified beet juice acidified to enable long-term storage and partially neutralized before fermentation. None of the salts synthesized through juice acidification and partial neutralization inhibited yeast fermentation at the levels evaluated in that work. Conversely, yeast fermentation rates significantly improved in the presence of ammonium salts, which appeared to compensate for nitrogen deficiencies. Capital and operating costs for production and storage of concentrated beet juice for an ethanol plant with a production capacity of 76 x 106 L y-1 were estimated on a dry-sugar basis as U.S. ¢34.0 kg-1 and ¢2.2 kg-1, respectively. Storage and processing techniques evaluated thus far prove that industrial beets are a technically-feasible sugar feedstock for ethanol production.

Shelf Life Extension of Tomato Paste Through Organoleptically Acceptable Concentration of Betel Leaf Essential Oil Under Accelerated Storage Environment.

PubMed

Basak, Suradeep

2018-05-01

This study was attempted with two objectives: (1) to find an acceptable concentration of betel leaf essential oil (BLEO) based on sensory evaluation that can be employed in tomato paste; (2) to evaluate the effect of the acceptable concentration of BLEO in the paste during accelerated storage under 89 ± 1.2% RH at 39 ± 1 °C. Linguistic data obtained from sensory evaluation of tomato paste treated with 4 different concentrations of BLEO were analyzed using fuzzy logic approach. The organoleptically acceptable concentration was determined to be 0.25 mg/g of BLEO in tomato paste. The effect of the selected concentration of BLEO on different physicochemical and microbial attributes of tomato paste during accelerated storage was studied. Untreated tomato paste was found to have 12% less total antioxidant capacity than treated paste at the end of storage. Based on a * /b * value in CIELAB color space, the BLEO treated paste efficiently extended the shelf life by 14 days with respect to untreated paste samples under accelerated storage conditions. BLEO comes with a tag contributing to green consumerism, and its application as food preservative is no less than a value addition to the product. Essential oil is considered to have promising potential as an alternative food preservative, and its use is practically possible if they could overcome the sensory barrier, while retaining the preservative potency. The importance of identifying the sensory attributes for commercial success of essential oil treated food product was considered in this study. It contributes to the potency of organoleptically acceptable concentration of BLEO in shelf life extension of tomato paste under accelerated storage conditions. At industrial level, the estimated shelf life of treated tomato paste can be increased by incorporating more hurdles alongside BLEO. © 2018 Institute of Food Technologists®.

Evaluating the long-term hydrology of an evapotranspiration-capillary barrier with a 1000 year design life: HYDROLOGY OF A 1000 YEAR ETC BARRIER

DOE Office of Scientific and Technical Information (OSTI.GOV)

Zhang, Z. Fred

A surface barrier (or cover) is a commonly used technology for subsurface remediation. A key function of the barrier is to reduce or eliminate the movement of meteoric precipitation into the underlying waste zone, where it could mobilize and transport contaminants. Surface barriers are expected to perform for centuries to millennia, yet there are very few examples of performance for periods longer than a decade. The Prototype Hanford Barrier was constructed in 1994 over an existing waste site to demonstrate its long-term performance for a design period of 1000 years. This barrier is a field-scale evapotranspiration-capillary (ETC) barrier. In thismore » design, the storage layer consists of 2-m-thick silt loam. The 19-year monitoring results show that the store-and-release mechanism for the ETC barrier worked efficiently as the storage layer was recharged in the winter season (November to March) and the stored water was released to the atmosphere in the summer season (April to October) via soil evaporation and plant transpiration. The capillary break functioned normally in improving the storage capacity and minimizing drainage. The maximum drainage observed through the ET barrier at any of the monitoring stations was only 0.178 mm yr-1 (under an enhanced precipitation condition), which is less than the design criterion. A very small amount (2.0 mm yr-1 on average) of runoff was observed during the 19-year monitoring period. The observed storage capacity of the storage layer was considerably (39%) larger than the estimated value based on the method of equilibrium of water pressure. After a controlled fire in 2008, the newly grown vegetation (primarily shallow-rooted grasses) could still release the stored water and summer precipitation to the atmosphere via transpiration. The findings are useful for predicting water storage and ET under different precipitation conditions and for the design of future barriers.« less

DPM — efficient storage in diverse environments

NASA Astrophysics Data System (ADS)

Hellmich, Martin; Furano, Fabrizio; Smith, David; Brito da Rocha, Ricardo; Álvarez Ayllón, Alejandro; Manzi, Andrea; Keeble, Oliver; Calvet, Ivan; Regala, Miguel Antonio

2014-06-01

Recent developments, including low power devices, cluster file systems and cloud storage, represent an explosion in the possibilities for deploying and managing grid storage. In this paper we present how different technologies can be leveraged to build a storage service with differing cost, power, performance, scalability and reliability profiles, using the popular storage solution Disk Pool Manager (DPM/dmlite) as the enabling technology. The storage manager DPM is designed for these new environments, allowing users to scale up and down as they need it, and optimizing their computing centers energy efficiency and costs. DPM runs on high-performance machines, profiting from multi-core and multi-CPU setups. It supports separating the database from the metadata server, the head node, largely reducing its hard disk requirements. Since version 1.8.6, DPM is released in EPEL and Fedora, simplifying distribution and maintenance, but also supporting the ARM architecture beside i386 and x86_64, allowing it to run the smallest low-power machines such as the Raspberry Pi or the CuBox. This usage is facilitated by the possibility to scale horizontally using a main database and a distributed memcached-powered namespace cache. Additionally, DPM supports a variety of storage pools in the backend, most importantly HDFS, S3-enabled storage, and cluster file systems, allowing users to fit their DPM installation exactly to their needs. In this paper, we investigate the power-efficiency and total cost of ownership of various DPM configurations. We develop metrics to evaluate the expected performance of a setup both in terms of namespace and disk access considering the overall cost including equipment, power consumptions, or data/storage fees. The setups tested range from the lowest scale using Raspberry Pis with only 700MHz single cores and a 100Mbps network connections, over conventional multi-core servers to typical virtual machine instances in cloud settings. We evaluate the combinations of different name server setups, for example load-balanced clusters, with different storage setups, from using a classic local configuration to private and public clouds.

A data driven model for the impact of IFT and density variations on CO2 storage capacity in geologic formations

NASA Astrophysics Data System (ADS)

Nomeli, Mohammad A.; Riaz, Amir

2017-09-01

Carbon dioxide (CO2) storage in depleted hydrocarbon reservoirs and deep saline aquifers is one of the most promising solutions for decreasing CO2 concentration in the atmosphere. One of the important issues for CO2 storage in subsurface environments is the sealing efficiency of low-permeable cap-rocks overlying potential CO2 storage reservoirs. Though we focus on the effect of IFT in this study as a factor influencing sealing efficiency or storage capacity, other factors such as interfacial interactions, wettability, pore radius and interfacial mass transfer also affect the mobility and storage capacity of CO2 phase in the pore space. The study of the variation of IFT is however important because the pressure needed to penetrate a pore depends on both the pore size and the interfacial tension. Hence small variations in IFT can affect flow across a large population of pores. A novel model is proposed to find the IFT of the ternary systems (CO2/brine-salt) in a range of temperatures (300-373 K), pressures (50-250 bar), and up to 6 molal salinity applicable to CO2 storage in geological formations through a multi-variant non-linear regression of experimental data. The method uses a general empirical model for the quaternary system CO2/brine-salts that can be made to coincide with experimental data for a variety of solutions. We introduce correction parameters into the model, which compensates for uncertainties, and enforce agreement with experimental data. The results for IFT show a strong dependence on temperature, pressure, and salinity. The model has been found to describe the experimental data in the appropriate parameter space with reasonable precision. Finally, we use the new model to evaluate the effects of formation depth on the actual efficiency of CO2 storage. The results indicate that, in the case of CO2 storage in deep subsurface environments as a global-warming mitigation strategy, CO2 storage capacity increases with reservoir depth.

Proactive replica checking to assure reliability of data in cloud storage with minimum replication

NASA Astrophysics Data System (ADS)

Murarka, Damini; Maheswari, G. Uma

2017-11-01

The two major issues for cloud storage systems are data reliability and storage costs. For data reliability protection, multi-replica replication strategy which is used mostly in current clouds acquires huge storage consumption, leading to a large storage cost for applications within the loud specifically. This paper presents a cost-efficient data reliability mechanism named PRCR to cut back the cloud storage consumption. PRCR ensures data reliability of large cloud information with the replication that might conjointly function as a price effective benchmark for replication. The duplication shows that when resembled to the standard three-replica approach, PRCR will scale back to consume only a simple fraction of the cloud storage from one-third of the storage, thence considerably minimizing the cloud storage price.

Limits, complementarity and improvement of Advanced SAR Interferometry monitoring of anthropogenic subsidence/uplift due to long term CO2 storage

NASA Astrophysics Data System (ADS)

de Michele, M.; Raucoules, D.; Rohmer, J.; Loschetter, A.; Raffard, D.; Le Gallo, Y.

2013-12-01

A prerequisite to the large scale industrial development of CO2 Capture and geological Storage is the demonstration that the storage is both efficient and safe. In this context, precise uplift/subsidence monitoring techniques constitute a key component of any CO2 storage risk management. Space-borne Differential SAR (Synthetic Aperture Radar) interferometry is a promising monitoring technique. It can provide valuable information on vertical positions of a set of scatterer undergoing surface deformation induced by volumetric changes through time and space caused by CO2 injection in deep aquifers. To what extent ? To date, InSAR techniques have been successfully used in a variety of case-studies involving the measure of surface deformation caused by subsurface fluid withdrawal / injection. For instance, groundwater flow characterization in complex aquifers systems, oil / gas field characterization, verification of enhanced oil recovery efficiency, monitoring of seasonal gas storage. The successful use of InSAR is strictly related to the favourable scattering conditions in terms of spatial distribution of targets and their temporal stability. In arid regions, natural radar scatterers density can be very high, exceeding 1,000 per square km. But future onshore industrial-scale CO2 storage sites are planned in more complex land-covers such as agricultural or vegetated terrains. Those terrains are characterized by poor to moderate radar scatterers density, which decrease the detection limits of the space-borne interferometric technique. The present study discusses the limits and constraints of advanced InSAR techniques applied to deformation measurements associated with CO2 injection/storage into deep aquifers in the presence of agricultural and vegetated land-covers. We explore different options to enhance the measurement performances of InSAR techniques. As a first option, we propose to optimize the deployment of a network of 'artificial' scatterers, i.e. corner reflectors (artificial devices installed on ground to provide high backscatter to the radar signal) to complement the existing 'natural' network. The methodology is iterative and adaptive to the spatial and temporal extent of the detectable deforming region. We take into account the need of a change in sensors characteristics (for a very long term monitoring 10-50 years) that could result in a need of re-organisation of the network. Our discussion is supported by the estimates of the expected spatio-temporal evolution of surface vertical displacements caused by CO2 injection at depth by combining the approximate analytical solutions for pressure build-up during CO2 injection in deep aquifers and the poro-elastic behaviour of the reservoir under injection. As second option, we then review different advanced InSAR algorithms that could improve the displacement measurements using natural scatterers over vegetated areas.

Estimation of small reservoir storage capacities in the São Francisco, Limpopo, Bandama and Volta river basins using remotely sensed surface areas

NASA Astrophysics Data System (ADS)

Rodrigues, Lineu; Senzanje, Aidan; Cecchi, Philippe; Liebe, Jens

2010-05-01

People living in areas with highly variable rainfall, experience droughts and floods and often have insecure livelihoods. Small multi-purpose reservoirs (SR) are a widely used form of infrastructures to provide people in such areas with water during the dry season, e.g. in the basins of São Francisco, Brazil, Limpopo, Zimbabwe, Bandama, Ivory Coast and Volta, Ghana. In these areas, the available natural flow in the streams is sometimes less than the flow required for water supply or irrigation, however water can be stored in times of surplus, for example, from a wet season to a dry season. Efficient water management and sound reservoir planning are hindered by the lack of information about the functioning of these reservoirs. Reservoirs in these regions were constructed in a series of projects funded by different agencies, at different times, with little or no coordination among the implementing partners. Poor record keeping and the lack of appropriate institutional support result in deficiencies of information on the capacity, operation, and maintenance of these structures. Estimating the storage capacity of dams is essential to the responsible management of water diversion. Most of SR in these basins have never been evaluated, possibly because the tools currently used for such measurement are labor-intensive, costly and time-consuming. The objective of this research was to develop methodology to estimate small reservoir capacities as a function of their remotely sensed surface areas in the São Francisco, Limpopo, Bandama and Volta basins, as a way to contribute to improve the water resource management in those catchments. Remote sensing was used to identify, localize and characterize small reservoirs. The surface area of each was calculated from satellite images. A sub-set of reservoirs was selected. For each reservoir in the sub-set, the surface area was estimated from field surveys, and storage capacity was estimated using information on reservoir surface area, depth and shape. Depth was measured using a stadia rod or a manual echosounder. For reservoirs in the sub-set, estimated surface area was used as an input into the triangulated irregular network model. With the surface area and depth, measured volume was calculated. Comparisons were made between estimates of surface area from field surveys and estimates of surface area from remote sensing. A linear regression analysis was carried out to establish the relationship between surface area and storage capacities. Within geomorphologically homogenous regions, one may expect a good correlation between the surface area, which may be determined through satellite observations, and the stored volume. Such a relation depends on the general shape of the slopes (convex, through straight, to concave). The power relationships between remotely sensed surface areas (m^2) and storage capacities of reservoirs (m^3) obtained were - Limpopo basin (Lower Mzingwane sub-catchment): Volume = 0.023083 x Area^1.3272 (R2 = 95%); Bandama basin (North of the basin in Ivory Coast): Volume = 0.00405 x Area^1.4953 (R2 = 88.9%); Volta basin (Upper East region of the Volta Basin in Ghana): Volume = 0.00857 × Area^1.43 (R2 = 97.5%); São Francisco basin (Preto river sub-catchment): Volume = 0.2643 x Area^1.1632 (R2 = 92.1%). Remote sensing was found to be a suitable means to detect small reservoirs and accurately measure their surface areas. The general relationship between measured reservoir volumes and their remotely sensed surface areas showed good accuracy for all four basins. Combining such relationships with periodical satellite-based reservoir area measurements may allow hydrologists and planners to have clear picture of water resource system in the Basins, especially in ungauged sub-basins.

Role of Pumped Storage Hydro Resources in Electricity Markets and System Operation: Preprint

DOE Office of Scientific and Technical Information (OSTI.GOV)

Ela, E.; Kirby, B.; Botterud, A.

2013-05-01

The most common form of utility- sized energy storage system is the pumped storage hydro system. Originally, these types of storage systems were economically viable simply because they displace more expensive generating units. However, over time, as those expensive units became more efficient and costs declined, pumped hydro storage units no longer have the operational edge. As a result, in the current electricity market environment, pumped storage hydro plants are struggling. To offset this phenomenon, certain market modifications should be addressed. This paper will introduce some of the challenges faced by pumped storage hydro plants in today's markets and purposemore » some solutions to those problems.« less

Estimation and evaluation of management options to control and/or reduce the risk of not complying with commercial sterility.

PubMed

Pujol, Laure; Albert, Isabelle; Magras, Catherine; Johnson, Nicholas Brian; Membré, Jeanne-Marie

2015-11-20

In a previous study, a modular process risk model, from the raw material reception to the final product storage, was built to estimate the risk of a UHT-aseptic line of not complying with commercial sterility (Pujol et al., 2015). This present study was focused on demonstrating how the model (updated version with uncertainty and variability separated and 2(nd) order Monte Carlo procedure run) could be used to assess quantitatively the influence of management options. This assessment was done in three steps: pinpoint which process step had the highest influence on the risk, identify which management option(s) could be the most effective to control and/or reduce the risk, and finally evaluate quantitatively the influence of changing process setting(s) on the risk. For Bacillus cereus, it was identified that during post-process storage in an aseptic tank, there was potentially an air re-contamination due to filter efficiency loss (efficiency loss due to successive in-place sterilizations after cleaning operations), followed by B. cereus growth. Two options were then evaluated: i) reducing by one fifth of the number of filter sterilizations before renewing the filters, ii) designing new UHT-aseptic lines without an aseptic tank, i.e. without a storage period after the thermal process and before filling. Considering the uncertainty in the model, it was not possible to confirm whether these options had a significant influence on the risk associated with B. cereus. On the other hand, for Geobacillus stearothermophilus, combinations of heat-treatment time and temperature enabling the control or reduction in risk by a factor of ca. 100 were determined; for ease of operational implementation, they were presented graphically in the form of iso-risk curves. For instance, it was established that a heat treatment of 138°C for 31s (instead of 138°C for 25s) enabled a reduction in risk to 18×10(-8) (95% CI=[10; 34]×10(-8)), instead of 578×10(-8) (95% CI=[429; 754]×10(-8)) initially. In conclusion, a modular risk model, as the one exemplified here with a UHT-aseptic line, is a valuable tool in process design and operation, bringing definitive quantitative elements into the decision making process. Copyright © 2015 Elsevier B.V. All rights reserved.

Optimizing tertiary storage organization and access for spatio-temporal datasets

NASA Technical Reports Server (NTRS)

Chen, Ling Tony; Rotem, Doron; Shoshani, Arie; Drach, Bob; Louis, Steve; Keating, Meridith

1994-01-01

We address in this paper data management techniques for efficiently retrieving requested subsets of large datasets stored on mass storage devices. This problem represents a major bottleneck that can negate the benefits of fast networks, because the time to access a subset from a large dataset stored on a mass storage system is much greater that the time to transmit that subset over a network. This paper focuses on very large spatial and temporal datasets generated by simulation programs in the area of climate modeling, but the techniques developed can be applied to other applications that deal with large multidimensional datasets. The main requirement we have addressed is the efficient access of subsets of information contained within much larger datasets, for the purpose of analysis and interactive visualization. We have developed data partitioning techniques that partition datasets into 'clusters' based on analysis of data access patterns and storage device characteristics. The goal is to minimize the number of clusters read from mass storage systems when subsets are requested. We emphasize in this paper proposed enhancements to current storage server protocols to permit control over physical placement of data on storage devices. We also discuss in some detail the aspects of the interface between the application programs and the mass storage system, as well as a workbench to help scientists to design the best reorganization of a dataset for anticipated access patterns.

An efficient numerical solution of the transient storage equations for solute transport in small streams

USGS Publications Warehouse

Runkel, Robert L.; Chapra, Steven C.

1993-01-01

Several investigators have proposed solute transport models that incorporate the effects of transient storage. Transient storage occurs in small streams when portions of the transported solute become isolated in zones of water that are immobile relative to water in the main channel (e.g., pools, gravel beds). Transient storage is modeled by adding a storage term to the advection-dispersion equation describing conservation of mass for the main channel. In addition, a separate mass balance equation is written for the storage zone. Although numerous applications of the transient storage equations may be found in the literature, little attention has been paid to the numerical aspects of the approach. Of particular interest is the coupled nature of the equations describing mass conservation for the main channel and the storage zone. In the work described herein, an implicit finite difference technique is developed that allows for a decoupling of the governing differential equations. This decoupling method may be applied to other sets of coupled equations such as those describing sediment-water interactions for toxic contaminants. For the case at hand, decoupling leads to a 50% reduction in simulation run time. Computational costs may be further reduced through efficient application of the Thomas algorithm. These techniques may be easily incorporated into existing codes and new applications in which simulation run time is of concern.

Evaluating Dihydroazulene/Vinylheptafulvene Photoswitches for Solar Energy Storage Applications.

PubMed

Wang, Zhihang; Udmark, Jonas; Börjesson, Karl; Rodrigues, Rita; Roffey, Anna; Abrahamsson, Maria; Nielsen, Mogens Brøndsted; Moth-Poulsen, Kasper

2017-08-10

Efficient solar energy storage is a key challenge in striving toward a sustainable future. For this reason, molecules capable of solar energy storage and release through valence isomerization, for so-called molecular solar thermal energy storage (MOST), have been investigated. Energy storage by photoconversion of the dihydroazulene/vinylheptafulvene (DHA/VHF) photothermal couple has been evaluated. The robust nature of this system is determined through multiple energy storage and release cycles at elevated temperatures in three different solvents. In a nonpolar solvent such as toluene, the DHA/VHF system can be cycled more than 70 times with less than 0.01 % degradation per cycle. Moreover, the [Cu(CH 3 CN) 4 ]PF 6 -catalyzed conversion of VHF into DHA was demonstrated in a flow reactor. The performance of the DHA/VHF couple was also evaluated in prototype photoconversion devices, both in the laboratory by using a flow chip under simulated sunlight and under outdoor conditions by using a parabolic mirror. Device experiments demonstrated a solar energy storage efficiency of up to 0.13 % in the chip device and up to 0.02 % in the parabolic collector. Avenues for future improvements and optimization of the system are also discussed. © 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

An overview of ALARA considerations during Yankee Atomic`s Component Removal Project

DOE Office of Scientific and Technical Information (OSTI.GOV)

Granados, B.; Babineau, G.; Colby, B.

1995-03-01

In Februrary 1992, Yankee Atomic Electric Company (YAEC) permanently shutdown Yankee Nuclear Power Station in Rowe, Massachusetts, after thirty-two years of efficient operation. Yankee`s plan decommissioning is to defer dismantlement until a low level radioactive waste (LLRW) disposal facility is available. The plant will be maintained in a safe storage condition until a firm contract for the disposal of LLRW generated during decommissioning can be secured. Limited access to a LLRW disposal facility may occur during the safe storage period. Yankee intends to use these opportunities to remove components and structures. A Component Removal Project (CRP) was initiated in 1993more » to take advantage of one of these opportunities. A Componenet Removal Project (CRP) was initiated in 1993 to take advantage of one of these opportunities. The CRP includes removal of four steam generators, the pressurizer, and segmentation of reactor vessel internals and preparation of LLRW for shipment and disposal at Chem-Nuclear`s Barnwell, South Carolina facility. The CRP is projected to be completed by June 1994 at an estimated total worker exposure of less than 160 person-rem.« less

Biomass Supply Logistics and Infrastructure

DOE Office of Scientific and Technical Information (OSTI.GOV)

Sokhansanj, Shahabaddine

2009-04-01

Feedstock supply system encompasses numerous unit operations necessary to move lignocellulosic feedstock from the place where it is produced (in the field or on the stump) to the start of the conversion process (reactor throat) of the Biorefinery. These unit operations, which include collection, storage, preprocessing, handling, and transportation, represent one of the largest technical and logistics challenges to the emerging lignocellulosic biorefining industry. This chapter briefly reviews methods of estimating the quantities of biomass followed by harvesting and collection processes based on current practices on handling wet and dry forage materials. Storage and queuing are used to deal withmore » seasonal harvest times, variable yields, and delivery schedules. Preprocessing can be as simple as grinding and formatting the biomass for increased bulk density or improved conversion efficiency, or it can be as complex as improving feedstock quality through fractionation, tissue separation, drying, blending, and densification. Handling and Transportation consists of using a variety of transport equipment (truck, train, ship) for moving the biomass from one point to another. The chapter also provides typical cost figures for harvest and processing of biomass.« less

Biomass supply logistics and infrastructure.

PubMed

Sokhansanj, Shahabaddine; Hess, J Richard

2009-01-01

Feedstock supply system encompasses numerous unit operations necessary to move lignocellulosic feedstock from the place where it is produced (in the field or on the stump) to the start of the conversion process (reactor throat) of the biorefinery. These unit operations, which include collection, storage, preprocessing, handling, and transportation, represent one of the largest technical and logistics challenges to the emerging lignocellulosic biorefining industry. This chapter briefly reviews the methods of estimating the quantities of biomass, followed by harvesting and collection processes based on current practices on handling wet and dry forage materials. Storage and queuing are used to deal with seasonal harvest times, variable yields, and delivery schedules. Preprocessing can be as simple as grinding and formatting the biomass for increased bulk density or improved conversion efficiency, or it can be as complex as improving feedstock quality through fractionation, tissue separation, drying, blending, and densification. Handling and transportation consists of using a variety of transport equipment (truck, train, ship) for moving the biomass from one point to another. The chapter also provides typical cost figures for harvest and processing of biomass.

Coexistence of perfect spin filtering for entangled electron pairs and high magnetic storage efficiency in one setup.

PubMed

Ji, T T; Bu, N; Chen, F J; Tao, Y C; Wang, J

2016-04-14

For Entangled electron pairs superconducting spintronics, there exist two drawbacks in existing proposals of generating entangled electron pairs. One is that the two kinds of different spin entangled electron pairs mix with each other. And the other is a low efficiency of entanglement production. Herein, we report the spin entanglement state of the ferromagnetic insulator (FI)/s-wave superconductor/FI structure on a narrow quantum spin Hall insulator strip. It is shown that not only the high production of entangled electron pairs in wider energy range, but also the perfect spin filtering of entangled electron pairs in the context of no highly spin-polarized electrons, can be obtained. Moreover, the currents for the left and right leads in the antiferromagnetic alignment both can be zero, indicating 100% tunnelling magnetoresistance with highly magnetic storage efficiency. Therefore, the spin filtering for entangled electron pairs and magnetic storage with high efficiencies coexist in one setup. The results may be experimentally demonstrated by measuring the tunnelling conductance and the noise power.

Estimating the ratio of pond size to irrigated soybean land in Mississippi: a case study

Treesearch

Ying Ouyang; G. Feng; J. Read; T. D. Leininger; J. N. Jenkins

2016-01-01

Although more on-farm storage ponds have been constructed in recent years to mitigate groundwater resources depletion in Mississippi, little effort has been devoted to estimating the ratio of on-farm water storage pond size to irrigated crop land based on pond metric and its hydrogeological conditions.  In this study, two simulation scenarios were chosen to...

Application of a stream-aquifer model to Monument Creek for development of a method to estimate transit losses for reusable water, El Paso County, Colorado

USGS Publications Warehouse

Kuhn, Gerhard; Arnold, L. Rick

2006-01-01

The U.S. Geological Survey, in cooperation with Colorado Springs Utilities, the Colorado Water Conservation Board, and the El Paso County Water Authority, began a study in 2004 to (1) apply a stream-aquifer model to Monument Creek, (2) use the results of the modeling to develop a transit-loss accounting program for Monument Creek, (3) revise the existing transit-loss accounting program for Fountain Creek to incorporate new water-management strategies and allow for incorporation of future changes in water-management strategies, and (4) integrate the two accounting programs into a single program with a Web-based user interface. The purpose of this report is to present the results of applying a stream-aquifer model to the Monument Creek study reach.Transit losses were estimated for reusable-water flows in Monument Creek that ranged from 1 to 200 cubic feet per second (ft3/s) and for native streamflows that ranged from 0 to 1,000 ft3/s. Transit losses were estimated for bank-storage, channel-storage, and evaporative losses. The same stream-aquifer model used in the previously completed (1988) Fountain Creek study was used in the Monument Creek study.Sixteen model nodes were established for the Monument Creek study reach, defining 15 subreaches. Channel length, aquifer length, and aquifer width for the subreaches were estimated from available topographic and geologic maps. Thickness of alluvial deposits and saturated thickness were estimated using lithologic and water-level data from about 100 wells and test holes in or near the Monument Creek study reach. Estimated average transmissivities for the subreaches ranged from 2,000 to 12,000 feet squared per day, and a uniform value of 0.20 was used for storage coefficient.Qualitative comparison of recorded and simulated streamflow at the downstream node for the calibration and verification simulations indicated that the two streamflows compared reasonably well. No adjustments were made to the model parameters. Differences between recorded and simulated streamflow volumes for all calibration and verification simulations ranged from about –8.8 to 7.5 percent; the total error for all simulations was about –0.7 percent.The model was used to estimate bank-storage losses for 10 to 15 native streamflows for each reusable-water flow of 1, 3, 5, 7, 10, 15, 20, 30, 40, 50, 100, and 200 ft3/s. Then the 10 to 15 bank-storage loss values were used in least-squares linear regression to estimate a relation between bank-storage loss and native streamflow for each of the 12 reusable-water flow rates. The 12 regression relations then were used to develop “look-up” tables of bank-storage loss for reusable-water flows ranging from 1 to 200 ft3/s (in 1-ft3/s increments). Additional model simulations indicated that (1) when the ratio of downstream native streamflow to upstream native streamflow was less than 1, bank-storage loss generally increased and (2) when the ratio of downstream native streamflow to upstream native streamflow was larger than 1, bank-storage loss generally decreased. These results were used to develop a bank-storage loss adjustment factor based on the ratio of native streamflow at the downstream node to native streamflow at the upstream node. The model also was used to estimate a recovery period, which is the length of time needed for the bank-storage loss to return to the stream. The recovery period was 1 day for six subreaches; 2 days for four subreaches; between 3 and 12 days for four subreaches; and 28 days for one subreach.Channel-storage losses are about 10 percent of the reusable-water flow for most of the subreaches, except for two subreaches, where the channel-storage losses are about 20 percent, and one subreach, where the losses are about 30 percent, owing to the greater channel lengths. Evaporative losses were estimated by the use of monthly pan-evaporation data and the incremental increase in stream width resulting from any reusable-water flows. Monthly pan-evaporation data were converted to a daily rate. The daily rate, when multiplied by the stream-width increase (in feet) that results from reusable-water flow and by the subreach length (in miles) gives the daily evaporative loss in cubic feet per second.

Using semantic data modeling techniques to organize an object-oriented database for extending the mass storage model

NASA Technical Reports Server (NTRS)

Campbell, William J.; Short, Nicholas M., Jr.; Roelofs, Larry H.; Dorfman, Erik

1991-01-01

A methodology for optimizing organization of data obtained by NASA earth and space missions is discussed. The methodology uses a concept based on semantic data modeling techniques implemented in a hierarchical storage model. The modeling is used to organize objects in mass storage devices, relational database systems, and object-oriented databases. The semantic data modeling at the metadata record level is examined, including the simulation of a knowledge base and semantic metadata storage issues. The semantic data model hierarchy and its application for efficient data storage is addressed, as is the mapping of the application structure to the mass storage.

Monitoring groundwater storage changes in the highly seasonal humid tropics: Validation of GRACE measurements in the Bengal Basin

NASA Astrophysics Data System (ADS)

Shamsudduha, M.; Taylor, R. G.; Longuevergne, L.

2012-02-01

Satellite monitoring of changes in terrestrial water storage provides invaluable information regarding the basin-scale dynamics of hydrological systems where ground-based records are limited. In the Bengal Basin of Bangladesh, we test the ability of satellite measurements under the Gravity Recovery and Climate Experiment (GRACE) to trace both the seasonality and trend in groundwater storage associated with intensive groundwater abstraction for dry-season irrigation and wet-season (monsoonal) recharge. We show that GRACE (CSR, GRGS) datasets of recent (2003 to 2007) groundwater storage changes (ΔGWS) correlate well (r = 0.77 to 0.93, p value < 0.0001) with in situ borehole records from a network of 236 monitoring stations and account for 44% of the total variation in terrestrial water storage (ΔTWS); highest correlation (r = 0.93, p value < 0.0001) and lowest root-mean-square error (<4 cm) are realized using a spherical harmonic product of CSR. Changes in surface water storage estimated from a network of 298 river gauging stations and soil-moisture derived from Land Surface Models explain 22% and 33% of ΔTWS, respectively. Groundwater depletion estimated from borehole hydrographs (-0.52 ± 0.30 km3 yr-1) is within the range of satellite-derived estimates (-0.44 to -2.04 km3 yr-1) that result from uncertainty associated with the simulation of soil moisture (CLM, NOAH, VIC) and GRACE signal-processing techniques. Recent (2003 to 2007) estimates of groundwater depletion are substantially greater than long-term (1985 to 2007) mean (-0.21 ± 0.03 km3 yr-1) and are explained primarily by substantial increases in groundwater abstraction for the dry-season irrigation and public water supplies over the last two decades.

Comparing groundwater recharge and storage variability from GRACE satellite observations with observed water levels and recharge model simulations

NASA Astrophysics Data System (ADS)

Allen, D. M.; Henry, C.; Demon, H.; Kirste, D. M.; Huang, J.

2011-12-01

Sustainable management of groundwater resources, particularly in water stressed regions, requires estimates of groundwater recharge. This study in southern Mali, Africa compares approaches for estimating groundwater recharge and understanding recharge processes using a variety of methods encompassing groundwater level-climate data analysis, GRACE satellite data analysis, and recharge modelling for current and future climate conditions. Time series data for GRACE (2002-2006) and observed groundwater level data (1982-2001) do not overlap. To overcome this problem, GRACE time series data were appended to the observed historical time series data, and the records compared. Terrestrial water storage anomalies from GRACE were corrected for soil moisture (SM) using the Global Land Data Assimilation System (GLDAS) to obtain monthly groundwater storage anomalies (GRACE-SM), and monthly recharge estimates. Historical groundwater storage anomalies and recharge were determined using the water table fluctuation method using observation data from 15 wells. Historical annual recharge averaged 145.0 mm (or 15.9% of annual rainfall) and compared favourably with the GRACE-SM estimate of 149.7 mm (or 14.8% of annual rainfall). Both records show lows and peaks in May and September, respectively; however, the peak for the GRACE-SM data is shifted later in the year to November, suggesting that the GLDAS may poorly predict the timing of soil water storage in this region. Recharge simulation results show good agreement between the timing and magnitude of the mean monthly simulated recharge and the regional mean monthly storage anomaly hydrograph generated from all monitoring wells. Under future climate conditions, annual recharge is projected to decrease by 8% for areas with luvisols and by 11% for areas with nitosols. Given this potential reduction in groundwater recharge, there may be added stress placed on an already stressed resource.

Heterogeneity, pore pressure, and injectate chemistry: Control measures for geologic carbon storage

DOE PAGES

Dewers, Thomas; Eichhubl, Peter; Ganis, Ben; ...

2017-11-28

Desirable outcomes for geologic carbon storage include maximizing storage efficiency, preserving injectivity, and avoiding unwanted consequences such as caprock or wellbore leakage or induced seismicity during and post injection. Here, to achieve these outcomes, three control measures are evident including pore pressure, injectate chemistry, and knowledge and prudent use of geologic heterogeneity. Field, experimental, and modeling examples are presented that demonstrate controllable GCS via these three measures. Observed changes in reservoir response accompanying CO 2 injection at the Cranfield (Mississippi, USA) site, along with lab testing, show potential for use of injectate chemistry as a means to alter fracture permeabilitymore » (with concomitant improvements for sweep and storage efficiency). Further control of reservoir sweep attends brine extraction from reservoirs, with benefit for pressure control, mitigation of reservoir and wellbore damage, and water use. State-of-the-art validated models predict the extent of damage and deformation associated with pore pressure hazards in reservoirs, timing and location of networks of fractures, and development of localized leakage pathways. Experimentally validated geomechanics models show where wellbore failure is likely to occur during injection, and efficiency of repair methods. Use of heterogeneity as a control measure includes where best to inject, and where to avoid attempts at storage. Lastly, an example is use of waste zones or leaky seals to both reduce pore pressure hazards and enhance residual CO 2 trapping.« less

Heterogeneity, pore pressure, and injectate chemistry: Control measures for geologic carbon storage

DOE Office of Scientific and Technical Information (OSTI.GOV)

Dewers, Thomas; Eichhubl, Peter; Ganis, Ben

Desirable outcomes for geologic carbon storage include maximizing storage efficiency, preserving injectivity, and avoiding unwanted consequences such as caprock or wellbore leakage or induced seismicity during and post injection. Here, to achieve these outcomes, three control measures are evident including pore pressure, injectate chemistry, and knowledge and prudent use of geologic heterogeneity. Field, experimental, and modeling examples are presented that demonstrate controllable GCS via these three measures. Observed changes in reservoir response accompanying CO 2 injection at the Cranfield (Mississippi, USA) site, along with lab testing, show potential for use of injectate chemistry as a means to alter fracture permeabilitymore » (with concomitant improvements for sweep and storage efficiency). Further control of reservoir sweep attends brine extraction from reservoirs, with benefit for pressure control, mitigation of reservoir and wellbore damage, and water use. State-of-the-art validated models predict the extent of damage and deformation associated with pore pressure hazards in reservoirs, timing and location of networks of fractures, and development of localized leakage pathways. Experimentally validated geomechanics models show where wellbore failure is likely to occur during injection, and efficiency of repair methods. Use of heterogeneity as a control measure includes where best to inject, and where to avoid attempts at storage. Lastly, an example is use of waste zones or leaky seals to both reduce pore pressure hazards and enhance residual CO 2 trapping.« less

Application of Electric Double-layer Capacitors for Energy Storage on Electric Railway

NASA Astrophysics Data System (ADS)

Hase, Shin-Ichi; Konishi, Takeshi; Okui, Akinobu; Nakamichi, Yoshinobu; Nara, Hidetaka; Uemura, Tadashi

The methods to stabilize power sources, which are the measures against voltage drop, power loading fluctuation, regeneration power lapse and so on, have been important issues in DC feeding circuits. Therefore, an energy storage medium that uses power efficiently and reduces above-mentioned problems is much concerned about. In recent years, development of energy storage medium is remarkable for drive-power supplies of electric vehicles. A number of applications of energy storage, for instance, battery and flywheel, have been investigated so far. A large-scale electric double-layer capacitor which is rapidly charged and discharged and offers long life, maintenance-free, low pollution and high efficiency, has been developed in wide range. We have compared the ability to charge batteries and electric double-layer capacitors. Therefore, we carried out fundamental studies about electric double-layer capacitors and its control. And we produced a prototype of energy storage for the DC electric railway system that consists of electric double-layer capacitors, diode bridge rectifiers, chopper system and PWM converters. From the charge and discharge tests of the prototype, useful information was obtained. This paper describes its characteristics and experimental results of energy storage system.

Data compilation, synthesis, and calculations used for organic-carbon storage and inventory estimates for mineral soils of the Mississippi River Basin

USGS Publications Warehouse

Buell, Gary R.; Markewich, Helaine W.

2004-01-01

U.S. Geological Survey investigations of environmental controls on carbon cycling in soils and sediments of the Mississippi River Basin (MRB), an area of 3.3 x 106 square kilometers (km2), have produced an assessment tool for estimating the storage and inventory of soil organic carbon (SOC) by using soil-characterization data from Federal, State, academic, and literature sources. The methodology is based on the linkage of site-specific SOC data (pedon data) to the soil-association map units of the U.S. Department of Agriculture State Soil Geographic (STATSGO) and Soil Survey Geographic (SSURGO) digital soil databases in a geographic information system. The collective pedon database assembled from individual sources presently contains 7,321 pedon records representing 2,581 soil series. SOC storage, in kilograms per square meter (kg/m2), is calculated for each pedon at standard depth intervals from 0 to 10, 10 to 20, 20 to 50, and 50 to 100 centimeters. The site-specific storage estimates are then regionalized to produce national-scale (STATSGO) and county-scale (SSURGO) maps of SOC to a specified depth. Based on this methodology, the mean SOC storage for the top meter of mineral soil in the MRB is approximately 10 kg/m2, and the total inventory is approximately 32.3 Pg (1 petagram = 109 metric tons). This inventory is from 2.5 to 3 percent of the estimated global mineral SOC pool.

Online Estimation of Allan Variance Coefficients Based on a Neural-Extended Kalman Filter

PubMed Central

Miao, Zhiyong; Shen, Feng; Xu, Dingjie; He, Kunpeng; Tian, Chunmiao

2015-01-01

As a noise analysis method for inertial sensors, the traditional Allan variance method requires the storage of a large amount of data and manual analysis for an Allan variance graph. Although the existing online estimation methods avoid the storage of data and the painful procedure of drawing slope lines for estimation, they require complex transformations and even cause errors during the modeling of dynamic Allan variance. To solve these problems, first, a new state-space model that directly models the stochastic errors to obtain a nonlinear state-space model was established for inertial sensors. Then, a neural-extended Kalman filter algorithm was used to estimate the Allan variance coefficients. The real noises of an ADIS16405 IMU and fiber optic gyro-sensors were analyzed by the proposed method and traditional methods. The experimental results show that the proposed method is more suitable to estimate the Allan variance coefficients than the traditional methods. Moreover, the proposed method effectively avoids the storage of data and can be easily implemented using an online processor. PMID:25625903

Terrestrial Waters and Sea Level Variations on Interannual Time Scale

NASA Technical Reports Server (NTRS)

Llovel, W.; Becker, M.; Cazenave, A.; Jevrejeva, S.; Alkama, R.; Decharme, B.; Douville, H.; Ablain, M.; Beckley, B.

2011-01-01

On decadal to multi-decadal time scales, thermal expansion of sea waters and land ice loss are the main contributors to sea level variations. However, modification of the terrestrial water cycle due to climate variability and direct anthropogenic forcing may also affect sea level. For the past decades, variations in land water storage and corresponding effects on sea level cannot be directly estimated from observations because these are almost non-existent at global continental scale. However, global hydrological models developed for atmospheric and climatic studies can be used for estimating total water storage. For the recent years (since mid-2002), terrestrial water storage change can be directly estimated from observations of the GRACE space gravimetry mission. In this study, we analyse the interannual variability of total land water storage, and investigate its contribution to mean sea level variability at interannual time scale. We consider three different periods that, each, depend on data availability: (1) GRACE era (2003-2009), (2) 1993-2003 and (3) 1955-1995. For the GRACE era (period 1), change in land water storage is estimated using different GRACE products over the 33 largest river basins worldwide. For periods 2 and 3, we use outputs from the ISBA-TRIP (Interactions between Soil, Biosphere, and Atmosphere-Total Runoff Integrating Pathways) global hydrological model. For each time span, we compare change in land water storage (expressed in sea level equivalent) to observed mean sea level, either from satellite altimetry (periods 1 and 2) or tide gauge records (period 3). For each data set and each time span, a trend has been removed as we focus on the interannual variability. We show that whatever the period considered, interannual variability of the mean sea level is essentially explained by interannual fluctuations in land water storage, with the largest contributions arising from tropical river basins.

Estimating variations in global surface water storage

NASA Astrophysics Data System (ADS)

Lettenmaier, D. P.

2016-12-01

Arguably, the most dramatic advances attributable to remote sensing in the hydrologic sciences have involved the extension of knowledge about processes and state variables from the scale of field experiments to regions, continents, and the entire Earth. However, despite the availability of information about total terrestrial water storage over large areas provided by the Gravity Recovery and Climate Experiment (GRACE) mission, we still have remarkably little knowledge of the magnitude of freshwater stored at and near the land surface, and its temporal scales of variation. This is especially true with respect to freshwater storage in natural lakes and manmade reservoirs. Estimates of the amount of water that could be stored in artificial reservoirs are in the neighborhood of 15% of the mean annual runoff from the continents or around 7-8000 km3. However, while global reservoir storage was increasing through about 1980 due to filling of new reservoirs constructed in the second half of the 20th century, it is not even known whether aggregate usable reservoir storage is increasing or decreasing, due to sedimentation effects. With the advent of satellite altimeters (mostly intended to measure ocean surface topography and or the surface elevation of glaciers and ice sheets), along with improved methods for estimating space-time variations in the extent of surface waters, new opportunities have arisen to piece together estimates of storage variations of fractions approaching one-half of the global surface water storage, for periods approaching two decades in some cases. Although this ability is nascent, it offers encouragement that, with the launch of the planned Surface Water and Ocean Topography (SWOT) satellite mission in 2020, which has as a specific objective the measurement of surface water variations, climate-scale understanding of this source of variability in Earth's surface water balance may be at hand. I discuss specific examples of the technology and resulting data sets, including successes and failures.

Estimating restorable wetland water storage at landscape scales

USGS Publications Warehouse

Jones, Charles Nathan; Evenson, Grey R.; McLaughlin, Daniel L.; Vanderhoof, Melanie; Lang, Megan W.; McCarty, Greg W.; Golden, Heather E.; Lane, Charles R.; Alexander, Laurie C.

2018-01-01

Globally, hydrologic modifications such as ditching and subsurface drainage have significantly reduced wetland water storage capacity (i.e., volume of surface water a wetland can retain) and consequent wetland functions. While wetland area has been well documented across many landscapes and used to guide restoration efforts, few studies have directly quantified the associated wetland storage capacity. Here, we present a novel raster-based approach to quantify both contemporary and potential (i.e., restorable) storage capacities of individual depressional basins across landscapes. We demonstrate the utility of this method by applying it to the Delmarva Peninsula, a region punctuated by both depressional wetlands and drainage ditches. Across the entire peninsula, we estimated that restoration (i.e., plugging ditches) could increase storage capacity by 80%. Focusing on an individual watershed, we found that over 59% of restorable storage capacity occurs within 20 m of the drainage network, and that 93% occurs within 1 m elevation of the drainage network. Our demonstration highlights widespread ditching in this landscape, spatial patterns of both contemporary and potential storage capacities, and clear opportunities for hydrologic restoration. In Delmarva and more broadly, our novel approach can inform targeted landscape-scale conservation and restoration efforts to optimize hydrologically mediated wetland functions.

Estimating restorable wetland water storage at landscape scales.

PubMed

Jones, Charles Nathan; Evenson, Grey R; McLaughlin, Daniel L; Vanderhoof, Melanie K; Lang, Megan W; McCarty, Greg W; Golden, Heather E; Lane, Charles R; Alexander, Laurie C

2018-01-01

Globally, hydrologic modifications such as ditching and subsurface drainage have significantly reduced wetland water storage capacity (i.e., volume of surface water a wetland can retain) and consequent wetland functions. While wetland area has been well documented across many landscapes and used to guide restoration efforts, few studies have directly quantified the associated wetland storage capacity. Here, we present a novel raster-based approach to quantify both contemporary and potential (i.e., restorable) storage capacities of individual depressional basins across landscapes. We demonstrate the utility of this method by applying it to the Delmarva Peninsula, a region punctuated by both depressional wetlands and drainage ditches. Across the entire peninsula, we estimated that restoration (i.e., plugging ditches) could increase storage capacity by 80%. Focusing on an individual watershed, we found that over 59% of restorable storage capacity occurs within 20 m of the drainage network, and that 93% occurs within 1 m elevation of the drainage network. Our demonstration highlights widespread ditching in this landscape, spatial patterns of both contemporary and potential storage capacities, and clear opportunities for hydrologic restoration. In Delmarva and more broadly, our novel approach can inform targeted landscape-scale conservation and restoration efforts to optimize hydrologically mediated wetland functions.

Comparing NetCDF and SciDB on managing and querying 5D hydrologic dataset

NASA Astrophysics Data System (ADS)

Liu, Haicheng; Xiao, Xiao

2016-11-01

Efficiently extracting information from high dimensional hydro-meteorological modelling datasets requires smart solutions. Traditional methods are mostly based on files, which can be edited and accessed handily. But they have problems of efficiency due to contiguous storage structure. Others propose databases as an alternative for advantages such as native functionalities for manipulating multidimensional (MD) arrays, smart caching strategy and scalability. In this research, NetCDF file based solutions and the multidimensional array database management system (DBMS) SciDB applying chunked storage structure are benchmarked to determine the best solution for storing and querying 5D large hydrologic modelling dataset. The effect of data storage configurations including chunk size, dimension order and compression on query performance is explored. Results indicate that dimension order to organize storage of 5D data has significant influence on query performance if chunk size is very large. But the effect becomes insignificant when chunk size is properly set. Compression of SciDB mostly has negative influence on query performance. Caching is an advantage but may be influenced by execution of different query processes. On the whole, NetCDF solution without compression is in general more efficient than the SciDB DBMS.

Characterizing the Sensitivity of Groundwater Storage to Climate variation in the Indus Basin

NASA Astrophysics Data System (ADS)

Huang, L.; Sabo, J. L.

2017-12-01

Indus Basin represents an extensive groundwater aquifer facing the challenge of effective management of limited water resources. Groundwater storage is one of the most important variables of water balance, yet its sensitivity to climate change has rarely been explored. To better estimate present and future groundwater storage and its sensitivity to climate change in the Indus Basin, we analyzed groundwater recharge/discharge and their historical evolution in this basin. Several methods are applied to specify the aquifer system including: water level change and storativity estimates, gravity estimates (GRACE), flow model (MODFLOW), water budget analysis and extrapolation. In addition, all of the socioeconomic and engineering aspects are represented in the hydrological system through the change of temporal and spatial distributions of recharge and discharge (e.g., land use, crop structure, water allocation, etc.). Our results demonstrate that the direct impacts of climate change will result in unevenly distributed but increasing groundwater storage in the short term through groundwater recharge. In contrast, long term groundwater storage will decrease as a result of combined indirect and direct impacts of climate change (e.g. recharge/discharge and human activities). The sensitivity of groundwater storage to climate variation is characterized by topography, aquifer specifics and land use. Furthermore, by comparing possible outcomes of different human interventions scenarios, our study reveals human activities play an important role in affecting the sensitivity of groundwater storage to climate variation. Over all, this study presents the feasibility and value of using integrated hydrological methods to support sustainable water resource management under climate change.

Combining plasma gasification and solid oxide cell technologies in advanced power plants for waste to energy and electric energy storage applications.

PubMed

Perna, Alessandra; Minutillo, Mariagiovanna; Lubrano Lavadera, Antonio; Jannelli, Elio

2018-03-01

The waste to energy (WtE) facilities and the renewable energy storage systems have a strategic role in the promotion of the "eco-innovation", an emerging priority in the European Union. This paper aims to propose advanced plant configurations in which waste to energy plants and electric energy storage systems from intermittent renewable sources are combined for obtaining more efficient and clean energy solutions in accordance with the "eco-innovation" approach. The advanced plant configurations consist of an electric energy storage (EES) section based on a solid oxide electrolyzer (SOEC), a waste gasification section based on the plasma technology and a power generation section based on a solid oxide fuel cell (SOFC). The plant configurations differ for the utilization of electrolytic hydrogen and oxygen in the plasma gasification section and in the power generation section. In the first plant configuration IAPGFC (Integrated Air Plasma Gasification Fuel Cell), the renewable oxygen enriches the air stream, that is used as plasma gas in the gasification section, and the renewable hydrogen is used to enrich the anodic stream of the SOFC in the power generation section. In the second plant configuration IHPGFC (Integrated Hydrogen Plasma Gasification Fuel Cell) the renewable hydrogen is used as plasma gas in the plasma gasification section, and the renewable oxygen is used to enrich the cathodic stream of the SOFC in the power generation section. The analysis has been carried out by using numerical models for predicting and comparing the systems performances in terms of electric efficiency and capability in realizing the waste to energy and the electric energy storage of renewable sources. Results have highlighted that the electric efficiency is very high for all configurations (35-45%) and, thanks to the combination with the waste to energy technology, the storage efficiencies are very attractive (in the range 72-92%). Copyright © 2017 Elsevier Ltd. All rights reserved.

A Micro grid design for a kind of household energy efficiency management system based on high permeability

NASA Astrophysics Data System (ADS)

Li, Siwei; Li, Jun; Liu, Zhuochu; Wang, Min; Yue, Liang

2017-05-01

After the access of household distributed photovoltaic, conditions of high permeability generally occur, which cut off the connection between distributed power supply and major network rapidly and use energy storage device to realize electrical energy storage. The above operations cannot be adequate for the power grid health after distributed power supply access any more from the perspective of economy and rationality. This paper uses the integration between device and device, integration between device and system and integration between system and system of household microgrid and household energy efficiency management, to design household microgrid building program and operation strategy containing household energy efficiency management, to achieve efficient integration of household energy efficiency management and household microgrid, to effectively solve problems of high permeability of household distributed power supply and so on.

[Estimation of vegetation carbon storage and density of forests at tree layer in Tibet, China.

PubMed

Liu, Shu Qin; Xia, Chao Zong; Feng, Wei; Zhang, Ke Bin; Ma, Li; Liu, Jian Kang

2017-10-01

The estimation of vegetation carbon storage and density of forests at tree layer in Tibet Autonomous Region was calculated based on the eighth forest inventory data using the biomass inventory method, as well as other attributes like tree trunk density and carbon content of different species. The results showed that the total carbon storage at tree layer in Tibet forest ecosystem was 1.067×10 9 t and the average carbon density was 72.49 t·hm -2 . The carbon storage at tree layer of different stands was in the order of arbor forest > scattered wood > sparse forest > alluvial tree. The carbon storage of different forest types at tree layer were in the order of shelterbelt > special purpose forest > timber forest > firewood forest. The proportion of the first mentioned two was 88.5%, and the average carbon density of different forest types at tree layer was 88.09 t·hm -2 . The carbon sto-rage and its distribution area at tree layer in different forest groups were in the same order, followed by mature forest > over mature forest > near mature forest > middle aged forest > young forest. The carbon storage in mature forests accounted for 50% of the total carbon storage at tree layer in diffe-rent forest groups. The carbon storage at tree layer in different forest groups increased first and then decreased with the increase of stand ages.

Heat and electricity from the Sun using parabolic dish collector systems

NASA Technical Reports Server (NTRS)

Truscello, V. C.; Williams, A. N.

1980-01-01

Point focus distributed receiver solar thermal technology for the production of electric power and of industrial process heat is addressed. The thermal power systems project which emphasizes the development of cost effective systems which will accelerate the commercialization and industrialization of plants up to 10 MWe, using parabolic dish collectors is described. The projected size of the isolated load market in the 1990-2000 time period is 300 to 1000 MW/year. Although this market is small in comparison to the grid connected utility market, it is indicated that by assuming only a 20 percent market penetration, up to 10,000 power modules per year would be required to meet this need. At a production rate of 25,000 units/year and assuming no energy storage, levelized bus bar energy costs of 75 mills/kWeh are projected. These numbers are based on what is believed to be a conservative estimate regarding engine-generator conversion efficiency (40 percent) for the 1990 time period. With a more optimistic estimate of efficiency (i.e., 45 percent), the bus bar cost decreases to about 67 mills/kWeh. At very large production rates (400,000 modules/years), the costs decrease to 58 mills/kWeh. Finally, the present status of the technology development effort is discussed.

Water demand for electricity in deep decarbonisation scenarios: a multi-model assessment

DOE Office of Scientific and Technical Information (OSTI.GOV)

Mouratiadou, I.; Bevione, M.; Bijl, D. L.

This study assesses the effects of deep electricity decarbonisation and shifts in the choice of power plant cooling technologies on global electricity water demand, using a suite of five integrated assessment models. We find that electricity sector decarbonisation results in co-benefits for water resources primarily due to the phase-out of water-intensive coal-based thermoelectric power generation, although these co-benefits vary substantially across decarbonisation scenarios. Wind and solar photovoltaic power represent a win-win option for both climate and water resources, but further expansion of nuclear or fossil- and biomass-fuelled power plants with carbon capture and storage may result in increased pressures onmore » the water environment. Further to these results, the paper provides insights on the most crucial factors of uncertainty with regards to future estimates of water demand. These estimates varied substantially across models in scenarios where the effects of decarbonisation on the electricity mix were less clear-cut. Future thermal and water efficiency improvements of power generation technologies and demand-side energy efficiency improvements were also identified to be important factors of uncertainty. We conclude that in order to ensure positive effects of decarbonisation on water resources, climate policy should be combined with technology-specific energy and/or water policies.« less

Analysis of Stationary, Photovoltaic-based Surface Power System Designs at the Lunar South Pole

NASA Technical Reports Server (NTRS)

Freeh, Joshua E.

2009-01-01

Combinations of solar arrays and either batteries or regenerative fuel cells are analyzed for a surface power system module at the lunar south pole. The systems are required to produce 5 kW of net electrical power in sunlight and 2 kW of net electrical power during lunar night periods for a 10-year period between 2020 and 2030. Systems-level models for energy conservation, performance, degradation, and mass are used to compare to various systems. The sensitivities of important and/or uncertain variables including battery specific energy, fuel cell operating voltage, and DC-DC converter efficiency are compared to better understand the system. Switching unit efficiency, battery specific energy, and fuel cell operating voltage appear to be important system-level variables for this system. With reasonably sized solar arrays, the regenerative fuel cell system has significantly lower mass than the battery system based on the requirements and assumptions made herein. The total operational time is estimated at about 10,000 hours in battery discharge/fuel cell mode and about 4,000 and 8,000 hours for the battery charge and electrolyzer modes, respectively. The estimated number of significant depth-of-discharge cycles for either energy storage system is less than 100 for the 10-year period.

Climate Change Effects of Forest Management and Substitution of Carbon-Intensive Materials and Fossil Fuels

NASA Astrophysics Data System (ADS)

Sathre, R.; Gustavsson, L.; Haus, S.; Lundblad, M.; Lundström, A.; Ortiz, C.; Truong, N.; Wikberg, P. E.

2016-12-01

Forests can play several roles in climate change mitigation strategies, for example as a reservoir for storing carbon and as a source of renewable materials and energy. To better understand the linkages and possible trade-offs between different forest management strategies, we conduct an integrated analysis where both sequestration of carbon in growing forests and the effects of substituting carbon intensive products within society are considered. We estimate the climate effects of directing forest management in Sweden towards increased carbon storage in forests, with more land set-aside for protection, or towards increased forest production for the substitution of carbon-intensive materials and fossil fuels, relative to a reference case of current forest management. We develop various scenarios of forest management and biomass use to estimate the carbon balances of the forest systems, including ecological and technological components, and their impacts on the climate in terms of cumulative radiative forcing over a 100-year period. For the reference case of current forest management, increasing the harvest of forest residues is found to give increased climate benefits. A scenario with increased set-aside area and the current level of forest residue harvest begins with climate benefits compared to the reference scenario, but the benefits cannot be sustained for 100 years because the rate of carbon storage in set-aside forests diminishes over time as the forests mature, but the demand for products and fuels remains. The most climatically beneficial scenario, expressed as reduced cumulative radiative forcing, in both the short and long terms is a strategy aimed at high forest production, high residue recovery rate, and high efficiency utilization of harvested biomass. Active forest management with high harvest level and efficient forest product utilization will provide more climate benefit, compared to reducing harvest and storing more carbon in the forest. Figure. Schematic diagram of complete modelled forest system including ecological and technological components, showing major flows of carbon.

Comparison and Tensorial Formulation of Inelastic Constitutive Models of Salt Rock Behaviour and Efficient Numerical Implementatio

NASA Astrophysics Data System (ADS)

Nagel, T.; Böttcher, N.; Görke, U. J.; Kolditz, O.

2014-12-01

The design process of geotechnical installations includes the application of numerical simulation tools for safety assessment, dimensioning and long term effectiveness estimations. Underground salt caverns can be used for the storage of natural gas, hydrogen, oil, waste or compressed air. For their design one has to take into account fluctuating internal pressures due to different levels of filling, the stresses imposed by the surrounding rock mass, irregular geometries and possibly heterogeneous material properties [3] in order to estimate long term cavern convergence as well as locally critical wall stresses. Constitutive models applied to rock salt are usually viscoplastic in nature and most often based on a Burgers-type rheological model extended by non-linear viscosity functions and/or plastic friction elements. Besides plastic dilatation, healing and damage are sometimes accounted for as well [2]. The scales of the geotechnical system to be simulated and the laboratory tests from which material parameters are determined are vastly different. The most common material testing modalities to determine material parameters in geoengineering are the uniaxial and the triaxial compression tests. Some constitutive formulations in widespread use are formulated based on equivalent rather than tensorial quantities valid under these specific test conditions and are subsequently applied to heterogeneous underground systems and complex 3D load cases. We show here that this procedure is inappropriate and can lead to erroneous results. We further propose alternative formulations of the constitutive models in question that restore their validity under arbitrary loading conditions. For an efficient numerical simulation, the discussed constitutive models are integrated locally with a Newton-Raphson algorithm that directly provides the algorithmically consistent tangent matrix for the global Newton iteration of the displacement based finite element formulation. Finally, the finite element implementations of the proposed constitutive formulations are employed to simulate an underground salt cavern used for compressed air energy storage with OpenGeoSys [1]. Transient convergence and stress fields are evaluated for typical fluctuating operation pressure regimes.

Inventory and review of aquifer storage and recovery in southern Florida

USGS Publications Warehouse

Reese, Ronald S.

2002-01-01

publications > water resources investigations > report 02-4036 US Department of the Interior US Geological Survey WRI 02-4036Inventory and Review of Aquifer Storage and Recovery in Southern Florida By Ronald S. ReeseTallahassee, Florida 2002 prepared as part of the U.S. Geological Survey Place-Based Studies Program ABSTRACT Abstract Introduction Inventory of Data Case Studies Summary References Tables Aquifer storage and recovery in southern Florida has been proposed on an unprecedented scale as part of the Comprehensive Everglades Restoration Plan. Aquifer storage and recovery wells were constructed or are under construction at 27 sites in southern Florida, mostly by local municipalities or counties located in coastal areas. The Upper Floridan aquifer, the principal storage zone of interest to the restoration plan, is the aquifer being used at 22 of the sites. The aquifer is brackish to saline in southern Florida, which can greatly affect the recovery of the freshwater recharged and stored.Well data were inventoried and compiled for all wells at most of the 27 sites. Construction and testing data were compiled into four main categories: (1) well identification, location, and construction data; (2) hydraulic test data; (3) ambient formation water-quality data; and (4) cycle testing data. Each cycle during testing or operation includes periods of recharge of freshwater, storage, and recovery that each last days or months. Cycle testing data include calculations of recovery efficiency, which is the percentage of the total amount of potable water recharged for each cycle that is recovered.Calculated cycle test data include potable water recovery efficiencies for 16 of the 27 sites. However, the number of cycles at most sites was limited; except for two sites, the highest number of cycles was five. Only nine sites had a recovery efficiency above 10 percent for the first cycle, and 10 sites achieved a recovery efficiency above 30 percent during at least one cycle. The highest recovery efficiency achieved per cycle was 84 percent for cycle 16 at the Boynton Beach site.Factors that could affect recovery of freshwater varied widely between sites. The thickness of the open storage zone at all sites ranged from 45 to 452 feet. For sites with the storage zone in the Upper Floridan aquifer, transmissivity based on tests of the storage zones ranged from 800 to 108,000 feet squared per day, leakance values indicated that confinement is not good in some areas, and the chloride concentration of ambient water ranged from 500 to 11,000 milligrams per liter.Based on review of four case studies and data from other sites, several hydrogeologic and design factors appear to be important to the performance of aquifer storage and recovery in the Floridan aquifer system. Performance is maximized when the storage zone is thin and located at the top of the Upper Floridan aquifer, and transmissivity and salinity of the storage zone are moderate (less than 30,000 feet squared per day and 3,000 milligrams per liter of chloride concentration, respectively). The structural setting at a site could also be important because of the potential for updip migration of a recharged freshwater bubble due to density contrast or loss of overlying confinement due to deformation.

Cyclic high temperature heat storage using borehole heat exchangers

NASA Astrophysics Data System (ADS)

Boockmeyer, Anke; Delfs, Jens-Olaf; Bauer, Sebastian

2016-04-01

The transition of the German energy supply towards mainly renewable energy sources like wind or solar power, termed "Energiewende", makes energy storage a requirement in order to compensate their fluctuating production and to ensure a reliable energy and power supply. One option is to store heat in the subsurface using borehole heat exchangers (BHEs). Efficiency of thermal storage is increasing with increasing temperatures, as heat at high temperatures is more easily injected and extracted than at temperatures at ambient levels. This work aims at quantifying achievable storage capacities, storage cycle times, injection and extraction rates as well as thermal and hydraulic effects induced in the subsurface for a BHE storage site in the shallow subsurface. To achieve these aims, simulation of these highly dynamic storage sites is performed. A detailed, high-resolution numerical simulation model was developed, that accounts for all BHE components in geometrical detail and incorporates the governing processes. This model was verified using high quality experimental data and is shown to achieve accurate simulation results with excellent fit to the available experimental data, but also leads to large computational times due to the large numerical meshes required for discretizing the highly transient effects. An approximate numerical model for each type of BHE (single U, double U and coaxial) that reduces the number of elements and the simulation time significantly was therefore developed for use in larger scale simulations. The approximate numerical model still includes all BHE components and represents the temporal and spatial temperature distribution with a deviation of less than 2% from the fully discretized model. Simulation times are reduced by a factor of ~10 for single U-tube BHEs, ~20 for double U-tube BHEs and ~150 for coaxial BHEs. This model is then used to investigate achievable storage capacity, injection and extraction rates as well as induced effects for varying storage cycle times, operating conditions and storage set-ups. A sensitivity analysis shows that storage efficiency strongly depends on the number of BHEs composing the storage site and the cycle time. Using a half-yearly cycle of heat injection and extraction with the maximum possible rates shows that the fraction of recovered heat increases with the number of storage cycles used, as initial losses due to heat conduction become smaller. Also, overall recovery rates of 70 to 80% are possible in the set-ups investigated. Temperature distribution in the geological heat storage site is most sensitive to the thermal conductivity of both borehole grouting and storage formation, while storage efficiency is dominated by the thermal conductivity of the storage formation. For the large cycle times of 6 months each used, heat capacity is less sensitive than the heat conductivity. Acknowledgments: This work is part of the ANGUS+ project (www.angusplus.de) and funded by the German Federal Ministry of Education and Research (BMBF) as part of the energy storage initiative "Energiespeicher".

77 FR 26045 - Agency Information Collection Activities; Proposed Collection; Comments Requested: Certification...

Federal Register 2010, 2011, 2012, 2013, 2014

2012-05-02

... Secure Gun Storage or Safety Devices ACTION: 30-Day Notice of information collection. The Department of... approved collection. (2) Title of the Form/Collection: Certification of Secure Gun Storage or Safety... to the availability of secure gun storage or safety devices. (5) An estimate of the total number of...

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Federal Register 2010, 2011, 2012, 2013, 2014

2012-02-22

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Calculating the ecosystem service of water storage in isolated wetlands using LiDAR in north central Florida, USA (presentation)

EPA Science Inventory

This study used remotely-sensed Light Detection and Ranging (LiDAR) data to estimate potential water storage capacity of isolated wetlands in north central Florida. The data were used to calculate the water storage potential of >8500 polygons identified as isolated wetlands. We f...

Calculating the ecosystem service of water storage in isolated wetlands using LIDAR in north central Florida, USA

EPA Science Inventory

This study used remotely-sensed Light Detection and Ranging (LiDAR) data to estimate potential water storage capacity of isolated wetlands in north central Florida. The data were used to calculate the water storage potential of >8500 polygons identified as isolated wetlands. We ...

76 FR 7192 - Agency Information Collection Activities; Submission to OMB for Review and Approval; Comment...

Federal Register 2010, 2011, 2012, 2013, 2014

2011-02-09

... Benzene Storage Vessels and Coke By-Product Recovery Plants (Renewal) AGENCY: Environmental Protection... Storage Vessels and Coke By-Product Recovery Plants (Renewal) ICR Numbers: EPA ICR Number 1080.13, OMB... operators of benzene storage vessels and coke by product recovery plants. Estimated Number of Respondents...

Sizing a PACS

NASA Astrophysics Data System (ADS)

Wilson, Dennis L.; Glicksman, Robert A.

1994-05-01

A Picture Archiving and Communications System (PACS) must be able to support the image rate of the medical treatment facility. In addition the PACS must have adequate working storage and archive storage capacity required. The calculation of the number of images per minute and the capacity of working storage and of archiving storage is discussed. The calculation takes into account the distribution of images over the different size of radiological images, the distribution between inpatient and outpatient, and the distribution over plain film CR images and other modality images. The support of the indirect clinical image load is difficult to estimate and is considered in some detail. The result of the exercise for a particular hospital is an estimate of the average size of the images and exams on the system, of the number of gigabytes of working storage, of the number of images moved per minute, of the size of the archive in gigabytes, and of the number of images that are to be moved by the archive per minute. The types of storage required to support the image rates and the capacity required are discussed.

Commercial Fishing Port Development in North Florida. [Escambia, Bay, Gulf, Franklin, Wakulla, Nassau, and Duval Counties

NASA Technical Reports Server (NTRS)

Mathis, K. (Principal Investigator); Cato, J. C.; Degner, P. D.; Landrum, P. D.; Prochaska, F. J.

1978-01-01

The author has identified the following significant results. Seven major counties were examined: Escambia, Bay, Gulf, Franklin, Wakulla, Nassau, and Duval. Population and economic activity were reviewed, along with commercial fishing and port facilities. Recommendations for five northwest Florida counties were based on interpretation of aerial photographs, satellite imagery, an aerial survey site visit, and published data. Major needs in Pensacola included docking, ice supply, and net and engine repair services. Costs for additional docks, an ice plant, and gear storage were estimated at $3,658,600. Port users in Panama City identified additional docking and gear storage as primary needs, along with gear repair and a marine railway. Estimated costs for dock and gear storage were $2,860,000. Added docking, gear storage, and ice supply, as well as gear electronics and diesel repair were needed in Port St. Joe. Costs were calculated at $1,231,500. Franklin County has three ports (Apalachicola - $1,107,000 for docks and gear storage, Eastpoint - $420,000 for additional docks, and Carrabella - $2,824,100 for docks, gear storage, and ice plant).

48 CFR 223.7102 - Exceptions.

Code of Federal Regulations, 2012 CFR

2012-10-01

... OF DEFENSE SOCIOECONOMIC PROGRAMS ENVIRONMENT, ENERGY AND WATER EFFICIENCY, RENEWABLE ENERGY TECHNOLOGIES, OCCUPATIONAL SAFETY, AND DRUG-FREE WORKPLACE Storage and Disposal of Toxic and Hazardous... Secretary of Energy; (6) The storage of materials that constitute military resources intended to be used...

Integrating Demand-Side Resources into the Electric Grid: Economic and Environmental Considerations

NASA Astrophysics Data System (ADS)

Fisher, Michael J.

Demand-side resources are taking an increasingly prominent role in providing essential grid services once provided by thermal power plants. This thesis considers the economic feasibility and environmental effects of integrating demand-side resources into the electric grid with consideration given to the diversity of market and environmental conditions that can affect their behavior. Chapter 2 explores the private economics and system-level carbon dioxide reduction when using demand response for spinning reserve. Steady end uses like lighting are more than twice as profitable as seasonal end uses because spinning reserve is needed year-round. Avoided carbon emission damages from using demand response instead of fossil fuel generation for spinning reserve are sufficient to justify incentives for demand response resources. Chapter 3 quantifies the system-level net emissions rate and private economics of behind-the-meter energy storage. Net emission rates are lower than marginal emission rates for power plants and in-line with estimates of net emission rates from grid-level storage. The economics are favorable for many buildings in regions with high demand charges like California and New York, even without subsidies. Future penetration into regions with average charges like Pennsylvania will depend greatly on installation cost reductions and wholesale prices for ancillary services. Chapter 4 outlines a novel econometric model to quantify potential revenues from energy storage that reduces demand charges. The model is based on a novel predictive metric that is derived from the building's load profile. Normalized revenue estimates are independent of the power capacity of the battery holding other performance characteristics equal, which can be used to calculate the profit-maximizing storage size. Chapter 5 analyzes the economic feasibility of flow batteries in the commercial and industrial market. Flow batteries at a 4-hour duration must be less expensive on a dollar per installed kWh basis, often by 20-30%, to break even with shorter duration li-ion or lead-acid despite allowing for deeper depth of discharge and superior cycle life. These results are robust to assumptions of tariff rates, battery round-trip efficiencies, amount of solar generation and whether the battery can participate in the wholesale energy and ancillary services markets.

Methane adsorption in nanoporous carbon: the numerical estimation of optimal storage conditions

NASA Astrophysics Data System (ADS)

Ortiz, L.; Kuchta, B.; Firlej, L.; Roth, M. W.; Wexler, C.

2016-05-01

The efficient storage and transportation of natural gas is one of the most important enabling technologies for use in energy applications. Adsorption in porous systems, which will allow the transportation of high-density fuel under low pressure, is one of the possible solutions. We present and discuss extensive grand canonical Monte Carlo (GCMC) simulation results of the adsorption of methane into slit-shaped graphitic pores of various widths (between 7 Å and 50 Å), and at pressures P between 0 bar and 360 bar. Our results shed light on the dependence of film structure on pore width and pressure. For large widths, we observe multi-layer adsorption at supercritical conditions, with excess amounts even at large distances from the pore walls originating from the attractive interaction exerted by a very high-density film in the first layer. We are also able to successfully model the experimental adsorption isotherms of heterogeneous activated carbon samples by means of an ensemble average of the pore widths, based exclusively on the pore-size distributions (PSD) calculated from subcritical nitrogen adsorption isotherms. Finally, we propose a new formula, based on the PSD ensemble averages, to calculate the isosteric heat of adsorption of heterogeneous systems from single-pore-width calculations. The methods proposed here will contribute to the rational design and optimization of future adsorption-based storage tanks.

[Estimation of Aedes aegypti (L.) (Diptera: Culicidae) productivity in households and public spaces in a dengue endemic city in Colombia].

PubMed

Alcalá, Lucas; Quintero, Juliana; González-Uribe, Catalina; Brochero, Helena

2015-01-01

Aedes aegypti is a vector for the dengue virus in Colombia. Its productivity can be estimated using pupal counts. To determine Ae. aegypti productivity in households and public spaces in Girardot (Colombia) during both wet and dry seasons. The amount of Ae. aegypti pupae was evaluated in 20 randomly selected clusters in Girardot, each consisting of 100 households and public spaces. Inspections were performed during the rainy (February-May, 2011), and dry (August-September, 2011) seasons. House, container, Breteau, person and hectare pupae indices were estimated. During the rainy season households contributed 94% to the total number of pupae (n=7,098) while only 6% (n=482) were found in public spaces. In the dry season, 98% (n=9,138) of pupae were found in households and 2% (n=223), in public spaces. Low water-storage tanks and tanks for washing purposes provided >87% of pupae in households, whereas jars, tires and sinks contained most pupae in public spaces. High pupal densities were observed in public spaces during the rainy season and in streets and schools in the dry season. There were no significant differences in the index per person (rainy season=1.0; dry season=1.3) or per hectare (rainy season=0.96, dry season=0.45) between seasons. High Ae. aegypti pupal densities were found inside households in low water-storage tanks and tanks for washing purposes during both the dry and rainy seasons. Public spaces provided more aquatic habitats during the rainy season. Vector control strategies targeting these containers could allow a more rational use of resources and increase efficiency.

Large-Scale Total Water Storage and Water Flux Changes over the Arid and Semiarid Parts of the Middle East from GRACE and Reanalysis Products

NASA Astrophysics Data System (ADS)

Forootan, E.; Safari, A.; Mostafaie, A.; Schumacher, M.; Delavar, M.; Awange, J. L.

2017-05-01

Previous studies indicate that water storage over a large part of the Middle East has been decreased over the last decade. Variability in the total (hydrological) water flux (TWF, i.e., precipitation minus evapotranspiration minus runoff) and water storage changes of the Tigris-Euphrates river basin and Iran's six major basins (Khazar, Persian, Urmia, Markazi, Hamun, and Sarakhs) over 2003-2013 is assessed in this study. Our investigation is performed based on the TWF that are estimated as temporal derivatives of terrestrial water storage (TWS) changes from the Gravity Recovery and Climate Experiment (GRACE) products and those from the reanalysis products of ERA-Interim and MERRA-Land. An inversion approach is applied to consistently estimate the spatio-temporal changes of soil moisture and groundwater storage compartments of the seven basins during the study period from GRACE TWS, altimetry, and land surface model products. The influence of TWF trends on separated water storage compartments is then explored. Our results, estimated as basin averages, indicate negative trends in the maximums of TWF peaks that reach up to -5.2 and -2.6 (mm/month/year) over 2003-2013, respectively, for the Urmia and Tigris-Euphrates basins, which are most likely due to the reported meteorological drought. Maximum amplitudes of the soil moisture compartment exhibit negative trends of -11.1, -6.6, -6.1, -4.8, -4.7, -3.8, and -1.2 (mm/year) for Urmia, Tigris-Euphrates, Khazar, Persian, Markazi, Sarakhs, and Hamun basins, respectively. Strong groundwater storage decrease is found, respectively, within the Khazar -8.6 (mm/year) and Sarakhs -7.0 (mm/year) basins. The magnitude of water storage decline in the Urmia and Tigris-Euphrates basins is found to be bigger than the decrease in the monthly accumulated TWF indicating a contribution of human water use, as well as surface and groundwater flow to the storage decline over the study area.

Comparing the net cost of CSP-TES to PV deployed with battery storage

NASA Astrophysics Data System (ADS)

Jorgenson, Jennie; Mehos, Mark; Denholm, Paul

2016-05-01

Concentrated solar power with thermal energy storage (CSP-TES) is a unique source of renewable energy in that its energy can be shifted over time and it can provide the electricity system with dependable generation capacity. In this study, we provide a framework to determine if the benefits of CSP-TES (shiftable energy and the ability to provide firm capacity) exceed the benefits of PV and firm capacity sources such as long-duration battery storage or conventional natural gas combustion turbines (CTs). The results of this study using current capital cost estimates indicate that a combination of PV and conventional gas CTs provides a lower net cost compared to CSP-TES and PV with batteries. Some configurations of CSP-TES have a lower net cost than PV with batteries for even the lowest battery cost estimate. Using projected capital cost targets, however, some configurations of CSP-TES have a lower net cost than PV with either option for even the lowest battery cost estimate. The net cost of CSP-TES varies with configuration, and lower solar multiples coupled with less storage are more attractive at current cost levels, due to high component costs. However, higher solar multiples show a lower net cost using projected future costs for heliostats and thermal storage materials.

Cost-Efficient Storage of Cryogens

NASA Technical Reports Server (NTRS)

Fesmire, J. E.; Sass, J. P.; Nagy, Z.; Sojoumer, S. J.; Morris, D. L.; Augustynowicz, S. D.

2007-01-01

NASA's cryogenic infrastructure that supports launch vehicle operations and propulsion testing is reaching an age where major refurbishment will soon be required. Key elements of this infrastructure are the large double-walled cryogenic storage tanks used for both space vehicle launch operations and rocket propulsion testing at the various NASA field centers. Perlite powder has historically been the insulation material of choice for these large storage tank applications. New bulk-fill insulation materials, including glass bubbles and aerogel beads, have been shown to provide improved thermal and mechanical performance. A research testing program was conducted to investigate the thermal performance benefits as well as to identify operational considerations and associated risks associated with the application of these new materials in large cryogenic storage tanks. The program was divided into three main areas: material testing (thermal conductivity and physical characterization), tank demonstration testing (liquid nitrogen and liquid hydrogen), and system studies (thermal modeling, economic analysis, and insulation changeout). The results of this research work show that more energy-efficient insulation solutions are possible for large-scale cryogenic storage tanks worldwide and summarize the operational requirements that should be considered for these applications.

Thermal Analysis of Fluidized Bed and Fixed Bed Latent Heat Thermal Storage System

NASA Astrophysics Data System (ADS)

Beemkumar, N.; Karthikeyan, A.; Shiva Keshava Reddy, Kota; Rajesh, Kona; Anderson, A.

2017-05-01

Thermal energy storage technology is essential because its stores available energy at low cost. Objective of the work is to store the thermal energy in a most efficient method. This work is deal with thermal analysis of fluidized bed and fixed bed latent heat thermal storage (LHTS) system with different encapsulation materials (aluminium, brass and copper). D-Mannitol has been used as phase change material (PCM). Encapsulation material which is in orbicular shape with 4 inch diameter and 2 mm thickness orbicular shaped product is used. Therminol-66 is used as a heat transfer fluid (HTF). Arrangement of encapsulation material is done in two ways namely fluidized bed and fixed bed thermal storage system. Comparison was made between the performance of fixed bed and fluidized bed with different encapsulation material. It is observed that from the economical point of view aluminium in fluidized bed LHTS System has highest efficiency than copper and brass. The thermal energy storage system can be analyzed with fixed bed by varying mass flow rate of oil paves a way to find effective heat energy transfer.

Novel Integration of Perovskite Solar Cell and Supercapacitor Based on Carbon Electrode for Hybridizing Energy Conversion and Storage.

PubMed

Liu, Zhiyong; Zhong, Yan; Sun, Bo; Liu, Xingyue; Han, Jinghui; Shi, Tielin; Tang, Zirong; Liao, Guanglan

2017-07-12

Power packs integrating both photovoltaic parts and energy storage parts have gained great scientific and technological attention due to the increasing demand for green energy and the tendency for miniaturization and multifunctionalization in electronics industry. In this study, we demonstrate novel integration of perovskite solar cell and solid-state supercapacitor for power packs. The perovskite solar cell is integrated with the supercapacitor based on common carbon electrodes to hybridize photoelectric conversion and energy storage. The power pack achieves a voltage of 0.84 V when the supercapacitor is charged by the perovskite solar cell under the AM 1.5G white light illumination with a 0.071 cm 2 active area, reaching an energy storage proportion of 76% and an overall conversion efficiency of 5.26%. When the supercapacitor is precharged at 1.0 V, an instant overall output efficiency of 22.9% can be achieved if the perovskite solar cell and supercapacitor are connected in series, exhibiting great potential in the applications of solar energy storage and flexible electronics such as portable and wearable devices.

Portable and Error-Free DNA-Based Data Storage.

PubMed

Yazdi, S M Hossein Tabatabaei; Gabrys, Ryan; Milenkovic, Olgica

2017-07-10

DNA-based data storage is an emerging nonvolatile memory technology of potentially unprecedented density, durability, and replication efficiency. The basic system implementation steps include synthesizing DNA strings that contain user information and subsequently retrieving them via high-throughput sequencing technologies. Existing architectures enable reading and writing but do not offer random-access and error-free data recovery from low-cost, portable devices, which is crucial for making the storage technology competitive with classical recorders. Here we show for the first time that a portable, random-access platform may be implemented in practice using nanopore sequencers. The novelty of our approach is to design an integrated processing pipeline that encodes data to avoid costly synthesis and sequencing errors, enables random access through addressing, and leverages efficient portable sequencing via new iterative alignment and deletion error-correcting codes. Our work represents the only known random access DNA-based data storage system that uses error-prone nanopore sequencers, while still producing error-free readouts with the highest reported information rate/density. As such, it represents a crucial step towards practical employment of DNA molecules as storage media.

Enhancement of efficiency of storage and processing of food raw materials using radiation technologies

DOE Office of Scientific and Technical Information (OSTI.GOV)

Gracheva, A. Yu.; Zav’yalov, M. A.; Ilyukhina, N. V.

The work is dedicated to improvement of efficiency of storage and processing of food raw materials using radiation technologies. International practice of radiation processing of food raw materials is presented and an increase in the consumption of irradiated food products is shown. The prospects of using radiation technologies for the processing of food products in Russia are discussed. The results of studies of radiation effects on various food products and packaging film by γ radiation and accelerated electrons are presented.

A Hadoop-based Molecular Docking System

NASA Astrophysics Data System (ADS)

Dong, Yueli; Guo, Quan; Sun, Bin

2017-10-01

Molecular docking always faces the challenge of managing tens of TB datasets. It is necessary to improve the efficiency of the storage and docking. We proposed the molecular docking platform based on Hadoop for virtual screening, it provides the preprocessing of ligand datasets and the analysis function of the docking results. A molecular cloud database that supports mass data management is constructed. Through this platform, the docking time is reduced, the data storage is efficient, and the management of the ligand datasets is convenient.

High-performance Raman memory with spatio-temporal reversal

NASA Astrophysics Data System (ADS)

Vernaz-Gris, Pierre; Tranter, Aaron D.; Everett, Jesse L.; Leung, Anthony C.; Paul, Karun V.; Campbell, Geoff T.; Lam, Ping Koy; Buchler, Ben C.

2018-05-01

A number of techniques exist to use an ensemble of atoms as a quantum memory for light. Many of these propose to use backward retrieval as a way to improve the storage and recall efficiency. We report on a demonstration of an off-resonant Raman memory that uses backward retrieval to achieve an efficiency of $65\\pm6\\%$ at a storage time of one pulse duration. The memory has a characteristic decay time of 60 $\\mu$s, corresponding to a delay-bandwidth product of $160$.

Storage and flux of carbon in live trees, snags, and logs in the Chugach and Tongass national forests

Treesearch

Tara Barrett

2014-01-01

Carbon storage and flux estimates for the two national forests in Alaska are provided using inventory data from permanent plots established in 1995–2003 and remeasured in 2004–2010. Estimates of change are reported separately for growth, sapling recruitment, harvest, mortality, snag recruitment, salvage, snag falldown, and decay. Although overall aboveground carbon...

Global Patterns of Legacy Nitrate Storage in the Vadose Zone

NASA Astrophysics Data System (ADS)

Ascott, M.; Gooddy, D.; Wang, L.; Stuart, M.; Lewis, M.; Ward, R.; Binley, A. M.

2017-12-01

Global-scale nitrogen (N) budgets have been developed to quantify the impact of man's influence on the nitrogen cycle. However, these budgets often do not consider legacy effects such as accumulation of nitrate in the deep vadose zone. In this presentation we show that the vadose zone is an important store of nitrate which should be considered in future nitrogen budgets for effective policymaking. Using estimates of depth to groundwater and nitrate leaching for 1900-2000, we quantify for the first time the peak global storage of nitrate in the vadose zone, estimated as 605 - 1814 Teragrams (Tg). Estimates of nitrate storage are validated using previous national and basin scale estimates of N storage and observed groundwater nitrate data for North America and Europe. Nitrate accumulation per unit area is greatest in North America, China and Central and Eastern Europe where thick vadose zones are present and there is an extensive history of agriculture. In these areas the long solute travel time in the vadose zone means that the anticipated impact of changes in agricultural practices on groundwater quality may be substantially delayed. We argue that in these areas use of conventional nitrogen budget approaches is inappropriate and their continued use will lead to significant errors.

Lidar-derived estimate and uncertainty of carbon sink in successional phases of woody encroachment

NASA Astrophysics Data System (ADS)

Sankey, Temuulen; Shrestha, Rupesh; Sankey, Joel B.; Hardegree, Stuart; Strand, Eva

2013-07-01

encroachment is a globally occurring phenomenon that contributes to the global carbon sink. The magnitude of this contribution needs to be estimated at regional and local scales to address uncertainties present in the global- and continental-scale estimates, and guide regional policy and management in balancing restoration activities, including removal of woody plants, with greenhouse gas mitigation goals. The objective of this study was to estimate carbon stored in various successional phases of woody encroachment. Using lidar measurements of individual trees, we present high-resolution estimates of aboveground carbon storage in juniper woodlands. Segmentation analysis of lidar point cloud data identified a total of 60,628 juniper tree crowns across four watersheds. Tree heights, canopy cover, and density derived from lidar were strongly correlated with field measurements of 2613 juniper stems measured in 85 plots (30 × 30 m). Aboveground total biomass of individual trees was estimated using a regression model with lidar-derived height and crown area as predictors (Adj. R2 = 0.76, p < 0.001, RMSE = 0.58 kg). The predicted mean aboveground woody carbon storage for the study area was 677 g/m2. Uncertainty in carbon storage estimates was examined with a Monte Carlo approach that addressed major error sources. Ranges predicted with uncertainty analysis in the mean, individual tree, aboveground woody C, and associated standard deviation were 0.35 - 143.6 kg and 0.5 - 1.25 kg, respectively. Later successional phases of woody encroachment had, on average, twice the aboveground carbon relative to earlier phases. Woody encroachment might be more successfully managed and balanced with carbon storage goals by identifying priority areas in earlier phases of encroachment where intensive treatments are most effective.

An integrated suspended sediment budgeting of the agricultural Can Revull catchment (Mallorca, Spain)

NASA Astrophysics Data System (ADS)

Estrany, J.; Garcia, C.

2012-04-01

The Mediterranean region of Europe has a long history of human settlement and human impacts. The very high spatial and temporal variability of fluvial processes in the region also creates problems for measurement and monitoring and for assessment of effects. Extensive rainfed herbaceous crops are one of the most representative agricultural elements of this region, which should be one of the major factor affecting erosion processes. Although land use is commonly seen as resulting in increased sediment yields, the implementation of soil and water conservation practices can have the reverse effect. Sediment budgets offer a means to assess the sources, storage, rates of transport, yields, and efficiency of delivery of sediment for a range of catchment scales. Field measurements were conducted in Can Revull, a small agricultural catchment (1.03 km2) on the island of Mallorca. This study uses 137Cs measurements, sediment source fingerprinting and continuous turbidity records of four hydrological years (2004-2005 to 2007-2008) to quantify the individual components of the budget. A large proportion of the material mobilized from cultivated fields without conservation practices (gross erosion was 775 t yr-1; 1,270 t km-2 yr-1) was, however, subsequently deposited either within the field of origin (112 t yr-1; 180 t km-2 yr-1) or at intermediate locations between the source field and the channel network (field-to-channel conveyance loss was 591 t yr-1; 1,090 t km-2 yr-1). The estimates of sediment accumulation rates on the floodplain in the lower reaches of the catchment indicate that the mean sedimentation rate was 0.47 g cm-2 yr-1. This value was extrapolated to the total area of the floodplain to estimate a total annual conveyance loss or storage of 150 t yr-1. Monitoring at the catchment outlet over the study period indicated a mean annual suspended sediment yield of 7 t km-2 yr-1. The sum of the estimates of sediment yield and floodplain storage (157 t yr-1) was taken to represent the total annual input of suspended sediment to the channel system. This value was subsequently apportioned using the information provided by the fingerprinting investigation, to estimate the mass of sediment reaching the channel network from cultivated fields and from eroding channel banks. Thus the annual contribution from channel banks was estimated to be 84 t yr-1. In the case of the contributions from cultivated fields, the estimates obtained were, as expected, significantly less than the values of net soil loss from these zones provided by the 137Cs measurements due to conveyance losses associated to field-to-channel conveyance loss. The overall sediment delivery ratios (<1%) indicate that approximately 99% of the sediment mobilized by erosion within the Can Revull catchment is subsequently deposited before reaching the monitoring station. As such, the low sediment outputs from the study catchment should be seen as reflecting the importance of conveyance losses and storage rather than a lack of sediment mobilization from the catchment surface, although part of the catchment headwaters was modified historically by means of terraces and transverse walls to prevent erosion.

Development of the hybrid sulfur cycle for use with concentrated solar heat. I. Conceptual design

DOE PAGES

Gorensek, Maximilian B.; Corgnale, Claudio; Summers, William A.

2017-07-27

We propose a detailed conceptual design of a solar hybrid sulfur (HyS) cycle. Numerous design tradeoffs, including process operating conditions and strategies, methods of integration with solar energy sources, and solar design options were considered. A baseline design was selected, and process flowsheets were developed. Pinch analyses were performed to establish the limiting energy efficiency. Detailed material and energy balances were completed, and a full stream table prepared. Design assumptions include use of: location in the southwest US desert, falling particle concentrated solar receiver, indirect heat transfer via pressurized helium, continuous operation with thermal energy storage, liquid-fed electrolyzer with PBImore » membrane, and bayonet-type acid decomposer. Thermochemical cycle efficiency for the HyS process was estimated to be 35.0%, LHV basis. The solar-to-hydrogen (STH) energy conversion ratio was 16.9%. This thus exceeds the Year 2015 DOE STCH target of STH >10%, and shows promise for meeting the Year 2020 target of 20%.« less

Triangular covariance factorizations for. Ph.D. Thesis. - Calif. Univ.

NASA Technical Reports Server (NTRS)

Thornton, C. L.

1976-01-01

An improved computational form of the discrete Kalman filter is derived using an upper triangular factorization of the error covariance matrix. The covariance P is factored such that P = UDUT where U is unit upper triangular and D is diagonal. Recursions are developed for propagating the U-D covariance factors together with the corresponding state estimate. The resulting algorithm, referred to as the U-D filter, combines the superior numerical precision of square root filtering techniques with an efficiency comparable to that of Kalman's original formula. Moreover, this method is easily implemented and involves no more computer storage than the Kalman algorithm. These characteristics make the U-D method an attractive realtime filtering technique. A new covariance error analysis technique is obtained from an extension of the U-D filter equations. This evaluation method is flexible and efficient and may provide significantly improved numerical results. Cost comparisons show that for a large class of problems the U-D evaluation algorithm is noticeably less expensive than conventional error analysis methods.