49 CFR 173.172 - Aircraft hydraulic power unit fuel tank.

Code of Federal Regulations, 2013 CFR

2013-10-01

... 49 Transportation 2 2013-10-01 2013-10-01 false Aircraft hydraulic power unit fuel tank. 173.172... Class 1 and Class 7 § 173.172 Aircraft hydraulic power unit fuel tank. Aircraft hydraulic power unit... consist of an aluminum pressure vessel made from tubing and having welded heads. Primary containment of...

49 CFR 173.172 - Aircraft hydraulic power unit fuel tank.

Code of Federal Regulations, 2010 CFR

2010-10-01

... 49 Transportation 2 2010-10-01 2010-10-01 false Aircraft hydraulic power unit fuel tank. 173.172... Class 1 and Class 7 § 173.172 Aircraft hydraulic power unit fuel tank. Aircraft hydraulic power unit... consist of an aluminum pressure vessel made from tubing and having welded heads. Primary containment of...

Optimal traits of plant hydraulic capacitance as an adaptation to hydroclimatic variability

NASA Astrophysics Data System (ADS)

Hartzell, S. R.; Bartlett, M. S., Jr.; Porporato, A. M.

2016-12-01

Hydraulic capacitance allows plants to uptake and store water when it is abundant. This stored water is utilized during periods of water stress, decreasing tissue damage and increasing carbon assimilation. By providing a more consistent and readily accessible water supply, it buffers water stress variability across daily and seasonal timescales. The rate of plant water storage and withdrawal varies widely between plant species and is principally governed by several plant hydraulic parameters, principally the hydraulic capacitance, the total water storage capacity, and the conductance between xylem and water storage tissue. The timescale of the plant response to changes in environmental conditions may be related to the timescale of relevant environmental variability. For example, the Baobab tree (Adansonia), which grows in an environment with very strong seasonal rainfall variability, has a relatively long timescale of hydraulic response, while an evergreen tree such as Pinus taeda, which mainly contends with daily and inter-rainfall moisture variability, has a much shorter timescale of hydraulic response. Here a model of hydraulic capacitance is coupled to a resistance model of soil-plant-atmosphere continuum. We force this model with stochastic rainfall and examine plant responses to moisture variability at various timescales. Optimal plant hydraulic properties are examined as a function of mean soil moisture (daily variability), mean period between rainfall events (inter-rainfall variability), and seasonal rainfall variability, and the relative importance of each type of variability in shaping plant water use strategies is assessed. Results are compared to typical hydraulic parameters of plants growing under specific environmental conditions. Values of hydraulic traits which optimize carbon assimilation and water use efficiency are found; these values are dependent on mean environmental conditions as well as the timescale of environmental variability.

Powered orthosis and attachable power-assist device with Hydraulic Bilateral Servo System.

PubMed

Ohnishi, Kengo; Saito, Yukio; Oshima, Toru; Higashihara, Takanori

2013-01-01

This paper discusses the developments and control strategies of exoskeleton-type robot systems for the application of an upper limb powered orthosis and an attachable power-assist device for care-givers. Hydraulic Bilateral Servo System, which consist of a computer controlled motor, parallel connected hydraulic actuators, position sensors, and pressure sensors, are installed in the system to derive the joint motion of the exoskeleton arm. The types of hydraulic component structure and the control strategy are discussed in relation to the design philosophy and target joints motions.

Selection of axial hydraulic turbines for low-head microhydropower plants

NASA Astrophysics Data System (ADS)

Šoukal, J.; Pochylý, F.; Varchola, M.; Parygin, A. G.; Volkov, A. V.; Khovanov, G. P.; Naumov, A. V.

2015-12-01

The creation of highly efficient hydroturbines for low-head microhydropower plants is considered. The use of uncontrolled (propeller) hydroturbines is a promising means of minimizing costs and the time for their recoupment. As an example, experimental results from Brno University of Technology are presented. The model axial hydraulic turbine produced by Czech specialists performs well. The rotor diameter of this turbine is 194 mm. In the design of the working rotor, ANSYS Fluent software is employed. Means of improving the efficiency of microhydropower plants by optimal selection of the turbine parameters in the early stages of design are outlined. The energy efficiency of the hydroturbine designed for use in a microhydropower plant may be assessed on the basis of the coefficient of energy utilization, which is a function of the total losses in all the pipeline elements and losses in the channel including the hydroturbine rotor. The limit on the coefficient of energy utilization in the pressure pipeline is the hydraulic analog of the Betz-Joukowsky limit, which is widely used in the design of wind generators. The proposed approach is experimentally verified at Moscow Power Engineering Institute. A model axial hydraulic turbine with four different rotors is designed for the research. The diameter of all four rotors is the same: 80 mm. The pipeline takes the form of a siphon. Working rotor R2, designed with parameter optimization, is characterized by the highest coefficient of energy utilization of the pressure pipeline and maximum efficiency. That confirms that the proposed approach is a promising means of maximizing the overall energy efficiency of the microhydropower plant.

Power generation costs and ultimate thermal hydraulic power limits in hypothetical advanced designs with natural circulation

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

Duffey, R.B.; Rohatgi, U.S.

Maximum power limits for hypothetical designs of natural circulation plants can be described analytically. The thermal hydraulic design parameters are those which limit the flow, being the elevations, flow areas, and loss coefficients. WE have found some simple ``design`` equations for natural circulation flow to power ratio, and for the stability limit. The analysis of historical and available data for maximum capacity factor estimation shows 80% to be reasonable and achievable. The least cost is obtained by optimizing both hypothetical plant performance for a given output,a nd the plant layout and design. There is also scope to increase output andmore » reduce cost by considering design variations of primary and secondary pressure, and by optimizing component elevations and loss coefficients. The design limits for each are set by stability and maximum flow considerations, which deserve close and careful evaluation.« less

46 CFR 111.97-5 - Electric and hydraulic power supply.

Code of Federal Regulations, 2013 CFR

2013-10-01

... ELECTRIC SYSTEMS-GENERAL REQUIREMENTS Electric Power-Operated Watertight Door Systems § 111.97-5 Electric and hydraulic power supply. (a) Each electric motor-driven door operating system must have the same.... (f) The source of power for each hydraulically operated watertight door system using an independent...

46 CFR 111.97-5 - Electric and hydraulic power supply.

Code of Federal Regulations, 2012 CFR

2012-10-01

... ELECTRIC SYSTEMS-GENERAL REQUIREMENTS Electric Power-Operated Watertight Door Systems § 111.97-5 Electric and hydraulic power supply. (a) Each electric motor-driven door operating system must have the same.... (f) The source of power for each hydraulically operated watertight door system using an independent...

46 CFR 111.97-5 - Electric and hydraulic power supply.

Code of Federal Regulations, 2010 CFR

2010-10-01

... ELECTRIC SYSTEMS-GENERAL REQUIREMENTS Electric Power-Operated Watertight Door Systems § 111.97-5 Electric and hydraulic power supply. (a) Each electric motor-driven door operating system must have the same.... (f) The source of power for each hydraulically operated watertight door system using an independent...

46 CFR 111.97-5 - Electric and hydraulic power supply.

Code of Federal Regulations, 2011 CFR

2011-10-01

... ELECTRIC SYSTEMS-GENERAL REQUIREMENTS Electric Power-Operated Watertight Door Systems § 111.97-5 Electric and hydraulic power supply. (a) Each electric motor-driven door operating system must have the same.... (f) The source of power for each hydraulically operated watertight door system using an independent...

46 CFR 111.97-5 - Electric and hydraulic power supply.

Code of Federal Regulations, 2014 CFR

2014-10-01

... ELECTRIC SYSTEMS-GENERAL REQUIREMENTS Electric Power-Operated Watertight Door Systems § 111.97-5 Electric and hydraulic power supply. (a) Each electric motor-driven door operating system must have the same.... (f) The source of power for each hydraulically operated watertight door system using an independent...

River channel morphology and hydraulics properties due to introduction of plant basket hydraulic structures for river channel management

NASA Astrophysics Data System (ADS)

Kałuża, Tomasz; Radecki-Pawlik, Artur; Plesiński, Karol; Walczak, Natalia; Szoszkiewicz, Krzysztof; Radecki-Pawlik, Bartosz

2016-04-01

In the present time integrated water management is directly connected with management and direct works in river channels themselves which are taking into account morphological processes in rivers and improve flow conditions. Our work focused on the hydraulic and hydrodynamic consequences upon the introduction of the concept of the improvement of the hydromorphological conditions of the Flinta River in a given reach following river channel management concept. Based on a comprehensive study of the hydromorphological state of the river, four sections were selected where restoration measures can efficiently improve river habitat conditions in the river. For each section a set of technical and biological measures were proposed and implemented in practice. One of the proposed solutions was to construct plant basket hydraulic structures (PBHS) within the river channel, which are essentially plant barriers working as sediment traps, changing river channel morphology and are in line with concepts of Water Framework Directive. These relatively small structures work as crested weirs and unquestionably change the channel morphology. Along our work we show the results of three-year long (2013-2015) systematic measurements that provided information on the morphological consequences of introducing such structures into a river channel. Our main conclusions are as follows: 1. Plant basket hydraulic structures cause changes in hydrodynamic conditions and result in sediment accumulation and the formation of river backwaters upstream and downstream the obstacle; 2. The introduced plant basket hydraulic structures cause plant debris accumulation which influences the hydrodynamic flow conditions; 3. The installation of plant basket hydraulic structures on the river bed changes flow pattern as well as flow hydrodynamic conditions causing river braiding process; 4. The erosion rate below the plant basket hydraulic structures is due to the hydraulic work conditions of the PBHS and its

Ecosystem-scale plant hydraulic strategies inferred from remotely-sensed soil moisture

NASA Astrophysics Data System (ADS)

Bassiouni, M.; Good, S. P.; Higgins, C. W.

2017-12-01

Characterizing plant hydraulic strategies at the ecosystem scale is important to improve estimates of evapotranspiration and to understand ecosystem productivity and resilience. However, quantifying plant hydraulic traits beyond the species level is a challenge. The probability density function of soil moisture observations provides key information about the soil moisture states at which evapotranspiration is reduced by water stress. Here, an inverse Bayesian approach is applied to a standard bucket model of soil column hydrology forced with stochastic precipitation inputs. Through this approach, we are able to determine the soil moisture thresholds at which stomata are open or closed that are most consistent with observed soil moisture probability density functions. This research utilizes remotely-sensed soil moisture data to explore global patterns of ecosystem-scale plant hydraulic strategies. Results are complementary to literature values of measured hydraulic traits of various species in different climates and previous estimates of ecosystem-scale plant isohydricity. The presented approach provides a novel relation between plant physiological behavior and soil-water dynamics.

Numerical modeling for the retrofit of the hydraulic cooling subsystems in operating power plant

NASA Astrophysics Data System (ADS)

AlSaqoor, S.; Alahmer, A.; Al Quran, F.; Andruszkiewicz, A.; Kubas, K.; Regucki, P.; Wędrychowicz, W.

2017-08-01

This paper presents the possibility of using the numerical methods to analyze the work of hydraulic systems on the example of a cooling system of a power boiler auxiliary devices. The variety of conditions at which hydraulic system that operated in specific engineering subsystems requires an individualized approach to the model solutions that have been developed for these systems modernizing. A mathematical model of a series-parallel propagation for the cooling water was derived and iterative methods were used to solve the system of nonlinear equations. The results of numerical calculations made it possible to analyze different variants of a modernization of the studied system and to indicate its critical elements. An economic analysis of different options allows an investor to choose an optimal variant of a reconstruction of the installation.

What plant hydraulics can tell us about responses to climate-change droughts.

PubMed

Sperry, John S; Love, David M

2015-07-01

Climate change exposes vegetation to unusual drought, causing declines in productivity and increased mortality. Drought responses are hard to anticipate because canopy transpiration and diffusive conductance (G) respond to drying soil and vapor pressure deficit (D) in complex ways. A growing database of hydraulic traits, combined with a parsimonious theory of tree water transport and its regulation, may improve predictions of at-risk vegetation. The theory uses the physics of flow through soil and xylem to quantify how canopy water supply declines with drought and ceases by hydraulic failure. This transpiration 'supply function' is used to predict a water 'loss function' by assuming that stomatal regulation exploits transport capacity while avoiding failure. Supply-loss theory incorporates root distribution, hydraulic redistribution, cavitation vulnerability, and cavitation reversal. The theory efficiently defines stomatal responses to D, drying soil, and hydraulic vulnerability. Driving the theory with climate predicts drought-induced loss of plant hydraulic conductance (k), canopy G, carbon assimilation, and productivity. Data lead to the 'chronic stress hypothesis' wherein > 60% loss of k increases mortality by multiple mechanisms. Supply-loss theory predicts the climatic conditions that push vegetation over this risk threshold. The theory's simplicity and predictive power encourage testing and application in large-scale modeling. © 2015 The Authors. New Phytologist © 2015 New Phytologist Trust.

Representing Plant Hydraulics in a Global Model: Updates to the Community Land Model

NASA Astrophysics Data System (ADS)

Kennedy, D.; Swenson, S. C.; Oleson, K. W.; Lawrence, D. M.; Fisher, R.; Gentine, P.

2017-12-01

In previous versions, the Community Land Model has used soil moisture to stand in for plant water status, with transpiration and photosynthesis driven directly by soil water potential. This eschews significant literature demonstrating the importance of plant hydraulic traits in the dynamics of water flow through the soil-plant-atmosphere continuum and in the regulation of stomatal aperture. In this study we install a simplified hydraulic framework to represent vegetation water potential and to regulate root water uptake and turbulent fluxes. Plant hydraulics allow for a more explicit representation of plant water status, which improves the physical basis for many processes represented in CLM. This includes root water uptake and the attenuation of photosynthesis and transpiration with drought. Model description is accompanied by results from a point simulation based at the Caxiuanã flux tower site in Eastern Amazonia, covering a throughfall exclusion experiment from 2001-2003. Including plant hydraulics improves the response to drought forcing compared to previous versions of CLM. Parameter sensitivity is examined at the same site and presented in the context of estimating hydraulic parameters in a global model.

Elevated ozone concentration decreases whole-plant hydraulic conductance and disturbs water use regulation in soybean plants.

PubMed

Zhang, Wei-Wei; Wang, Miao; Wang, Ai-Ying; Yin, Xiao-Han; Feng, Zhao-Zhong; Hao, Guang-You

2017-11-30

Elevated tropospheric ozone (O 3 ) concentration has been shown to affect many aspects of plant performance including detrimental effects on leaf photosynthesis and plant growth. However, it is not known whether such changes are accompanied by concomitant responses in plant hydraulic architecture and water relations, which would have great implications for plant growth and survival in face of unfavorable water conditions. A soybean (Glycine max (L.) Merr.) cultivar commonly used in Northeast China was exposed to non-filtered air (NF, averaged 24.0 nl l -1 ) and elevated O 3 concentrations (eO 3 , 40 nl l -1 supplied with NF air) in six open-top chambers for 50 days. The eO 3 treatment resulted in a significant decrease in whole-plant hydraulic conductance that is mainly attributable to the reduced hydraulic conductance of the root system and the leaflets, while stem and leaf petiole hydraulic conductance showed no significant response to eO 3 . Stomatal conductance of plants grown under eO 3 was lower during mid-morning but significantly higher at midday, which resulted in substantially more negative daily minimum water potentials. Moreover, excised leaves from the eO 3 treated plants showed significantly higher rates of water loss, suggesting a lower ability to withhold water when water supply is impeded. Our results indicate that, besides the direct detrimental effects of eO 3 on photosynthetic carbon assimilation, its influences on hydraulic architecture and water relations may also negatively affect O 3 -sensitive crops by deteriorating the detrimental effects of unfavorable water conditions. © 2017 Scandinavian Plant Physiology Society.

Dynamic aspects of soil water availability for isohydric plants: Focus on root hydraulic resistances

NASA Astrophysics Data System (ADS)

Couvreur, V.; Vanderborght, J.; Draye, X.; Javaux, M.

2014-11-01

Soil water availability for plant transpiration is a key concept in agronomy. The objective of this study is to revisit this concept and discuss how it may be affected by processes locally influencing root hydraulic properties. A physical limitation to soil water availability in terms of maximal flow rate available to plant leaves (Qavail) is defined. It is expressed for isohydric plants, in terms of plant-centered variables and properties (the equivalent soil water potential sensed by the plant, ψs eq; the root system equivalent conductance, Krs; and a threshold leaf water potential, ψleaf lim). The resulting limitation to plant transpiration is compared to commonly used empirical stress functions. Similarities suggest that the slope of empirical functions might correspond to the ratio of Krs to the plant potential transpiration rate. The sensitivity of Qavail to local changes of root hydraulic conductances in response to soil matric potential is investigated using model simulations. A decrease of radial conductances when the soil dries induces earlier water stress, but allows maintaining higher night plant water potentials and higher Qavail during the last week of a simulated 1 month drought. In opposition, an increase of radial conductances during soil drying provokes an increase of hydraulic redistribution and Qavail at short term. This study offers a first insight on the effect of dynamic local root hydraulic properties on soil water availability. By better understanding complex interactions between hydraulic processes involved in soil-plant hydrodynamics, better prospects on how root hydraulic traits mitigate plant water stress might be achieved.

Linking root hydraulic properties to carbon allocation patterns in annual plant

NASA Astrophysics Data System (ADS)

Hosseini, A.; Ewers, B. E.; Adjesiwor, A. T.; Kniss, A. R.

2017-12-01

Incorporation of root structure and function into biophysical models is an important tool to predict plant water and nutrient uptake from the soil, plant carbon (C) assimilation, partitioning and release to the soils. Most of the models describing root water uptake (RWU) are based on semi-empirical (i.e. built on physiological hypotheses, but still combined with empirical functions) approaches and hydraulic parameters involved are hardly available. Root conductance is essential to define the interaction between soil-to-root and canopy-to-atmosphere. Also root hydraulic limitations to water flow can impact gas exchange rates and plant biomass partitioning. In this study, sugar beet (B. vulgaris) seeds under two treatments, grass (Kentucky bluegrass) and no grass (control), were planted in 19 L plastic buckets in June 2016. Photosynthetic characteristics (e.g. gas exchange and chlorophyll fluorescence), leaf morphology and anatomy, root morphology and above and below ground biomass of the plants was monitored at 15, 30, 50, 70 and 90 days after planting (DAP). Further emphasis was placed on the limits to water flow by coupling of hydraulic conductance (k) whole root-system with water relation parameters and gas exchange rates in fully established plants.

Geomorphological and hydrological implications of a given hydraulic geometry relationship, beyond the power-law

NASA Astrophysics Data System (ADS)

Kim, JongChun; Paik, Kyungrock

2015-04-01

Channel geometry and hydraulic characteristics of a given river network, i.e., spatio-temporal variability of width, depth, and velocity, can be described as power functional relationships of flow discharge, named 'hydraulic geometry' (Leopold and Maddock, 1953). Many studies have focused on the implication of this power-law itself, i.e., self-similarity, and accordingly its exponents. Coefficients of the power functional relationships, on the contrary, have received little attention. They are often regarded as empirical constants, determined by 'best fitting' to the power-law without significant scientific implications. Here, we investigate and claim that power-law coefficients of hydraulic geometry relationships carry vital information of a given river system. We approach the given problem on the basis of 'basin hydraulic geometry' formulation (Stall and Fok, 1968) which decomposes power-law coefficients into more elementary constants. The linkage between classical power-law relationship (Leopold and Maddock, 1953) and the basin hydraulic geometry is provided by Paik and Kumar (2004). On the basis of this earlier study, it can be shown that coefficients and exponents of power-law hydraulic geometry are interrelated. In this sense, we argue that more elementary constants that constitute both exponents and coefficients carry important messages. In this presentation, we will demonstrate how these elementary constants vary over a wide range of catchments provided from Stall and Fok (1968) and Stall and Yang (1970). Findings of this study can provide new insights on fundamental understanding about hydraulic geometry relationships. Further, we expect that this understanding can help interpretation of hydraulic geometry relationship in the context of flood propagation through a river system as well. Keywords: Hydraulic geometry; Power-law; River network References Leopold, L. B., & Maddock, T. J. (1953). The hydraulic geometry of stream channels and some physiographic

On-line condition monitoring applications in nuclear power plants

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

Hastiemian, H. M.; Feltus, M. A.

2006-07-01

Existing signals from process instruments in nuclear power plants can be sampled while the plant is operating and analyzed to verify the static and dynamic performance of process sensors, identify process-to-sensor problems, detect instrument anomalies such as venturi fouling, measure the vibration of the reactor vessel and its internals, or detect thermal hydraulic anomalies within the reactor coolant system. These applications are important in nuclear plants to satisfy a variety of objectives such as: 1) meeting the plant technical specification requirements; 2) complying with regulatory regulations; 3) guarding against equipment and process degradation; 4) providing a means for incipient failuremore » detection and predictive maintenance; or 5) identifying the root cause of anomalies in equipment and plant processes. The technologies that are used to achieve these objectives are collectively referred to as 'on-line condition monitoring.' This paper presents a review of key elements of these technologies, provides examples of their use in nuclear power plants, and illustrates how they can be integrated into an on-line condition monitoring system for nuclear power plants. (authors)« less

Plant basket hydraulic structures (PBHS) as a new river restoration measure.

PubMed

Kałuża, Tomasz; Radecki-Pawlik, Artur; Szoszkiewicz, Krzysztof; Plesiński, Karol; Radecki-Pawlik, Bartosz; Laks, Ireneusz

2018-06-15

River restoration has become increasingly attractive worldwide as it provides considerable benefits to the environment as well as to the economy. This study focuses on changes of hydromorphological conditions in a small lowland river recorded during an experiment carried out in the Flinta River, central Poland. The proposed solution was a pilot project of the construction of vegetative sediment traps (plant basket hydraulic structures - PBHS). A set of three PBSH was installed in the riverbed in one row and a range of hydraulic parameters were recorded over a period of three years (six measurement sessions). Changes of sediment grain size were analysed, and the amount and size of plant debris in the plant barriers were recorded. Plant debris accumulation influencing flow hydrodynamics was detected as a result of the installation of vegetative sediment traps. Moreover, various hydromorphological processes in the river were initiated. Additional simulations based on the detected processes showed that the proposed plant basket hydraulic structures can improve the hydromorphological status of the river. Copyright © 2018 Elsevier B.V. All rights reserved.

Plant hydraulic controls over ecosystem responses to climate-enhanced disturbances

NASA Astrophysics Data System (ADS)

Mackay, D. S.; Ewers, B. E.; Reed, D. E.; Pendall, E.; McDowell, N. G.

2012-12-01

Climate-enhanced disturbances such as drought and insect infestation range in severity, contributing minor to severe stress to forests including forest mortality. While neither form of disturbance has been unambiguously implicated as a mechanism of mortality, both induce changes in water, carbon, and nutrient cycling that are key to understanding forest ecosystem response to, and recovery from, disturbance. Each disturbance type has different biophysical, ecohydrological, and biogeochemical signatures that potentially complicate interpretation and development of theory. Plant hydraulic function is arguably a unifying control over these responses to disturbance because it regulates stomatal conductance, leaf biochemistry, carbon (C) uptake and utilization, and nutrient cycling. We demonstrated this idea by focusing on water and C, including non-structural (NSC), resources, and nitrogen (N) uptake across a spectrum of forest ecosystems (e.g., northern temperate mixed forests, lodgepole pine forests in the Rocky Mountains, and pinon pine - juniper woodlands in New Mexico) using the Terrestrial Regional Ecosystem Exchange Simulator (TREES). TREES is grounded in the biophysics of water movement through soil and plants, respectively via hydraulic conductivity of the soil and cavitation of xylem. It combines this dynamic plant hydraulic conductance with canopy biochemical controls over photosynthesis, and the dynamics of structural and non-structural carbon through a carbon budget that responds to plant hydraulic status. As such, the model can be used to develop testable hypotheses on a multitude of disturbance and recovery responses including xylem dysfunction, stomatal and non-stomatal controls on photosynthesis and carbon allocation, respiration, and allocation to defense compounds. For each of the ecosystems we constrained and evaluated the model with allometry, sap flux and/or eddy covariance data, leaf gas exchange measurements, and vulnerability to cavitation data

18 CFR 420.51 - Hydroelectric power plant water use charges.

Code of Federal Regulations, 2013 CFR

2013-04-01

... increased hydraulic head available to the hydroelectric project as a result of investments by the Commission shall be charged one mill per kilowatt-hour of energy produced. (2) Owners of hydroelectric power plants... kilowatt-hour of energy produced. No charges for increased flows will be required when charges for...

18 CFR 420.51 - Hydroelectric power plant water use charges.

Code of Federal Regulations, 2011 CFR

2011-04-01

... increased hydraulic head available to the hydroelectric project as a result of investments by the Commission shall be charged one mill per kilowatt-hour of energy produced. (2) Owners of hydroelectric power plants... kilowatt-hour of energy produced. No charges for increased flows will be required when charges for...

18 CFR 420.51 - Hydroelectric power plant water use charges.

Code of Federal Regulations, 2012 CFR

2012-04-01

... increased hydraulic head available to the hydroelectric project as a result of investments by the Commission shall be charged one mill per kilowatt-hour of energy produced. (2) Owners of hydroelectric power plants... kilowatt-hour of energy produced. No charges for increased flows will be required when charges for...

18 CFR 420.51 - Hydroelectric power plant water use charges.

Code of Federal Regulations, 2014 CFR

2014-04-01

... increased hydraulic head available to the hydroelectric project as a result of investments by the Commission shall be charged one mill per kilowatt-hour of energy produced. (2) Owners of hydroelectric power plants... kilowatt-hour of energy produced. No charges for increased flows will be required when charges for...

Power Efficient Hydraulic Systems. Volume 1. Study Phase

DTIC Science & Technology

1988-07-01

AIRCRAFT SUBSYSTEMS TABLE 14. Baseline aircraft systems o HYDRAULIC SYSTEM o ELECTRICAL SYSTEM o 8000 PSI, 3 INDEPENDENT SYSTEMS o HVDC POWER o APU...neither aluminum nor titanium provide good wear surfaces. Hydraulic fittings and valve bodies appear to be excellent candidates for PM technology...Actuator Bodies Savings Over Steel ys. Time of Heat and 25% Over Treatment To Be Resolved T1-3AL-2.5V - Heat Treatment May Cause - Excellent

Hydraulic limits on maximum plant transpiration and the emergence of the safety-efficiency trade-off.

PubMed

Manzoni, Stefano; Vico, Giulia; Katul, Gabriel; Palmroth, Sari; Jackson, Robert B; Porporato, Amilcare

2013-04-01

Soil and plant hydraulics constrain ecosystem productivity by setting physical limits to water transport and hence carbon uptake by leaves. While more negative xylem water potentials provide a larger driving force for water transport, they also cause cavitation that limits hydraulic conductivity. An optimum balance between driving force and cavitation occurs at intermediate water potentials, thus defining the maximum transpiration rate the xylem can sustain (denoted as E(max)). The presence of this maximum raises the question as to whether plants regulate transpiration through stomata to function near E(max). To address this question, we calculated E(max) across plant functional types and climates using a hydraulic model and a global database of plant hydraulic traits. The predicted E(max) compared well with measured peak transpiration across plant sizes and growth conditions (R = 0.86, P < 0.001) and was relatively conserved among plant types (for a given plant size), while increasing across climates following the atmospheric evaporative demand. The fact that E(max) was roughly conserved across plant types and scales with the product of xylem saturated conductivity and water potential at 50% cavitation was used here to explain the safety-efficiency trade-off in plant xylem. Stomatal conductance allows maximum transpiration rates despite partial cavitation in the xylem thereby suggesting coordination between stomatal regulation and xylem hydraulic characteristics. © 2013 The Authors. New Phytologist © 2013 New Phytologist Trust.

A study on the optimal hydraulic loading rate and plant ratios in recirculation aquaponic system.

PubMed

Endut, Azizah; Jusoh, A; Ali, N; Wan Nik, W B; Hassan, A

2010-03-01

The growths of the African catfish (Clarias gariepinus) and water spinach (Ipomoea aquatica) were evaluated in recirculation aquaponic system (RAS). Fish production performance, plant growth and nutrient removal were measured and their dependence on hydraulic loading rate (HLR) was assessed. Fish production did not differ significantly between hydraulic loading rates. In contrast to the fish production, the water spinach yield was significantly higher in the lower hydraulic loading rate. Fish production, plant growth and percentage nutrient removal were highest at hydraulic loading rate of 1.28 m/day. The ratio of fish to plant production has been calculated to balance nutrient generation from fish with nutrient removal by plants and the optimum ratio was 15-42 gram of fish feed/m(2) of plant growing area. Each unit in RAS was evaluated in terms of oxygen demand. Using specified feeding regime, mass balance equations were applied to quantify the waste discharges from rearing tanks and treatment units. The waste discharged was found to be strongly dependent on hydraulic loading rate. 2009 Elsevier Ltd. All rights reserved.

Comparing hydraulic properties of soil-less substrates with natural soils: a more detailed look at hydraulic properties and their impact on plant water availability

NASA Astrophysics Data System (ADS)

Crawford, L.; Rivera, L. D.; van Iersel, M.

2013-12-01

Moisture release curves are often used when assessing plant-water relationships in soil-less substrates. However, differences between natural soils and soilless substrates make traditional assumptions about plant available water potentially invalid. If soil-less substrates are supposed to be treated like natural soils; why do plants begin wilting at very low water potentials (-10 to -30 kPa) and there is anywhere between 20 to 40 % water left (on a volumetric basis) in the soil (Abad et al., 2005; Arguedas et al., 2006; Ristvey et al, 2008) . We hypothesize that the fault lies in the methods used and the assumption that water potential is the only limiting factor in water availability to plants. Hydraulic properties, including the relationships that exist between plant available water, water content, and hydraulic conductivity of soil-less substrates have traditionally been characterized using instrumentation such as pressure plates, hanging water columns, and tempe cells. These approaches typically take a months and only provide data on select segments of the soil moisture release curve, and in the case of pressure plates and hanging water columns hydraulic conductivity is ignored and not very well understood. Using the Wind/Schindler Evaporation method more detailed measurements of these hydraulic properties can be measured in a less than a week. A more detailed look at the hydraulic properties of soil-less substrates and how they compare with natural soils may give us more insight into soil-plant-water-relations and what limits availability of water to plants. Soil moisture release curves and hydraulic conductivity curves of different soil-less substrates were compared with curves from typical agriculture soils to give insight into how these properties compare. Results of the soil moisture release curves showed that some soil-less substrates had comparable moisture release curves to agricultural soils while others had bi-modal curves indicating gap-gradation in

Identification of Dynamic Simulation Models for Variable Speed Pumped Storage Power Plants

NASA Astrophysics Data System (ADS)

Moreira, C.; Fulgêncio, N.; Silva, B.; Nicolet, C.; Béguin, A.

2017-04-01

This paper addresses the identification of reduced order models for variable speed pump-turbine plants, including the representation of the dynamic behaviour of the main components: hydraulic system, turbine governors, electromechanical equipment and power converters. A methodology for the identification of appropriated reduced order models both for turbine and pump operating modes is presented and discussed. The methodological approach consists of three main steps: 1) detailed pumped-storage power plant modelling in SIMSEN; 2) reduced order models identification and 3) specification of test conditions for performance evaluation.

Interrelations between hydraulic and mechanical stress adaptations in woody plants

PubMed Central

Ennos, A Roland; Fournier, Meriem

2008-01-01

The fields of plant water relations and plant biomechanics have traditionally been studied separately even though often the same tissues are responsible for water transport and mechanical support. There is now increasing evidence that hydraulic and mechanical adaptations may influence one another. We studied the changes in the hydraulic and mechanical properties of the wood along lateral roots of two species of buttressed trees. In these roots, the mechanical contstraints quantified by strain measurements are known to decrease distally. Further, we investigated the effect of mechanical loading on the vessel anatomy in these and four other species of tropical trees. We found that as the strain decreased, the wood became progressively less stiff and strong but the conductivity increased exponentially. This was reflected in that adaptations towards re-enforcing mechanically loaded areas resulted in xylem with fewer and smaller vessels. In addition a controlled growth experiment on three tree species showed that drought adaptation may results in plants with stronger and stiffer tissue. Our results indicate that hydraulic and mechanical stress adaptations may be interrelated, and so support recent studied suggesting that physiological responses are complex balances rather than pure optimisations. PMID:19704486

The Catastrophic Failure of Plant Hydraulic Networks Examined in Leaves

NASA Astrophysics Data System (ADS)

Marmottant, Philippe; Bienaimé, Diane; Brodribb, Timothy

Plants live a dangerous game: they have to facilitate water transport in their xylem conduits while minimizing the consequence of hydraulic failure. Indeed, as water flows under negative pressure inside these conduits, cavitation bubbles can spontaneously occur. By preventing the sap transport, they could lead to the plant death. This failure dynamics of this hydraulic network is poorly studied, while it has important ecological and bioengineering implications. Here, by using a simple optical method, we were able to directly visualize the spreading of cavitation bubbles within leaves. The air invasion also progresses by stop and go, from largest veins to smallest ones. In fact, in plants, conducts are linked by small valves called pits. By temporarily blocking bubbles they delay air invasion, until the pressure difference exceeds a threshold. To test the impact of these singular valves on the air invasion, we build a simulation based on the electrokinetic analogy. Taking in account the elasticity of the channel, each conduct becomes a hydraulic resistance coupled with a capacity. We show that we can reproduce the stop and go propagation in a variety of different network architectures. ERC Bubbleboost Grant number 614655.

Linking plant hydraulics and beta diversity in tropical forests

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

Christoffersen, Bradley; Meir, Patrick; McDowell, Nate G.

In tropical forests, studies of xylem traits governing water transport through plants, or ‘hydraulic architecture’ (Tyree et al., 1991), and changes in species composition across environmental gradients, or ‘beta diversity’ (Gentry, 1988; Ackerly & Cornwell, 2007), have progressedmostly in parallel until recently (Hao et al., 2008; Bartlett et al., 2016). In this issue of New Phytologist, Cosme et al. (pp. 000–5 000) present a timely contribution to the intersection of plant hydraulic architecture (HA) with trait-based community ecology. Building on previous biogeographical work that demonstrated shifts in species composition (beta diversity) across a gradient from valleys to plateaus in centralmore » Amazonia (Schietti et al., 2014), Cosme et al. explore how variation in HA might underpin this sorting, sampling pairs of congeneric species restrictedmostly to either plateau or valley habitats. Valley species had significantly lower wood density and higher hydraulically-weighted vessel diameter and vessel area. By contrast, trees with some of the largest hydraulically-weighted vessel diameters existed in tall, deciduous plateau species, while the leaf: sapwood area ratio decreased with height in valley but not plateau species. These intriguing results suggest that species differentiation in water transport traits mediate edaphic filtering along the valley-toplateau gradient, in contrast to previous work where wood mechanical support mediated valley-to-plateau environmental filtering (Fortunel et al., 2014).« less

Circadian rhythms of hydraulic conductance and growth are enhanced by drought and improve plant performance

PubMed Central

Caldeira, Cecilio F.; Jeanguenin, Linda; Chaumont, François; Tardieu, François

2014-01-01

Circadian rhythms enable plants to anticipate daily environmental variations, resulting in growth oscillations under continuous light. Because plants daily transpire up to 200% of their water content, their water status oscillates from favourable during the night to unfavourable during the day. We show that rhythmic leaf growth under continuous light is observed in plants that experience large alternations of water status during an entrainment period, but is considerably buffered otherwise. Measurements and computer simulations show that this is due to oscillations of plant hydraulic conductance and plasma membrane aquaporin messenger RNA abundance in roots during continuous light. A simulation model suggests that circadian oscillations of root hydraulic conductance contribute to acclimation to water stress by increasing root water uptake, thereby favouring growth and photosynthesis. They have a negative effect in favourable hydraulic conditions. Climate-driven control of root hydraulic conductance therefore improves plant performances in both stressed and non-stressed conditions. PMID:25370944

A HISTORICAL PERSPECTIVE OF NUCLEAR THERMAL HYDRAULICS

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

D’Auria, F; Rohatgi, Upendra S.

The nuclear thermal-hydraulics discipline was developed following the needs for nuclear power plants (NPPs) and, to a more limited extent, research reactors (RR) design and safety. As in all other fields where analytical methods are involved, nuclear thermal-hydraulics took benefit of the development of computers. Thermodynamics, rather than fluid dynamics, is at the basis of the development of nuclear thermal-hydraulics together with the experiments in complex two-phase situations, namely, geometry, high thermal density, and pressure.

Responses of hydraulics at the whole-plant level to simulated nitrogen deposition of different levels in Fraxinus mandshurica.

PubMed

Wang, Ai-Ying; Wang, Miao; Yang, Da; Song, Jia; Zhang, Wei-Wei; Han, Shi-Jie; Hao, Guang-You

2016-08-01

Nitrogen (N) deposition is expected to have great impact on forest ecosystems by affecting many aspects of plant-environmental interactions, one of which involves its influences on plant water relations through modifications of plant hydraulic architecture. However, there is a surprising lack of integrative study on tree hydraulic architecture responses to N deposition, especially at the whole-plant level. In the present study, we used a 5-year N addition experiment to simulate the effects of six different levels of N deposition (20-120 kg ha(-1) year(-1)) on growth and whole-plant hydraulic conductance of a dominant tree species (Fraxinus mandshurica Rupr.) from the typical temperate forest of NE China. The results showed that alleviation of N limitation by moderate concentrations of fertilization (20-80 kg ha(-1) year(-1)) promoted plant growth, but further N additions on top of the threshold level showed negative effects on plant growth. Growth responses of F. mandshurica seedlings to N addition of different concentrations were accompanied by corresponding changes in whole-plant hydraulic conductance; higher growth rate was accompanied by reduced whole-plant hydraulic conductance (Kplant) and higher leaf water-use efficiency. A detailed analysis on hydraulic conductance of different components of the whole-plant water transport pathway revealed that changes in root and leaf hydraulic conductance, rather than that of the stem, were responsible for Kplant responses to N fertilization. Both plant growth and hydraulic architecture responses to increasing levels of N addition were not linear, i.e., the correlation between measured parameters and N availability exhibited bell-shaped curves with peak values observed at medium levels of N fertilization. Changes in hydraulic architecture in response to fertilization found in the present study may represent an important underlying mechanism for the commonly observed changes in water-related tree performances

Engineering rhizosphere hydraulics: pathways to improve plant adaptation to drought

NASA Astrophysics Data System (ADS)

Ahmed, Mutez; Zarebanadkouki, Mohsen; Ahmadi, Katayoun; Kroener, Eva; Kostka, Stanley; Carminati, Andrea

2017-04-01

Developing new technologies to optimize the use of water in irrigated croplands is of increasing importance. Recent studies have drawn attention to the role of mucilage in shaping rhizosphere hydraulic properties and regulating root water uptake. During drying mucilage keeps the rhizosphere wet and conductive, but upon drying it turns hydrophobic limiting root water uptake. Here we introduced the concept of rhizoligands, defined as additives that 1) rewet the rhizosphere and 2) reduce mucilage swelling hereby reducing the rhizosphere conductivity. We then tested its effect on rhizosphere water dynamics and transpiration. The following experiments were carried out to test if selected surfactants behave as a rhizoligand. We used neutron radiography to monitor water redistribution in the rhizosphere of lupine and maize irrigated with water and rhizoligand solution. In a parallel experiment, we tested the effect of rhizoligand on the transpiration rate of lupine and maize subjected to repeated drying and wetting cycles. We also measured the effect of rhizoligand on the maximum swelling of mucilage and the saturated hydraulic conductivity of soil mixed with various mucilage concentrations. The results were then simulated using a root water uptake model. Rhizoligand treatment quickly and uniformly rewetted the rhizosphere of maize and lupine. Interestingly, rhizoligand also reduced transpiration during drying/wetting cycles. Evaporation from the bare soil was of minor importance. Our hypothesis is that the reduction in transpiration was triggered by the interaction between rhizoligand and mucilage exuded by roots. This hypothesis is supported by the fact that rhizoligand reduced the maximum swelling of mucilage, increased its viscosity, and decreased the hydraulic conductivity of soil-mucilage mixtures. The reduced conductivity of the rhizosphere induced a moderate stress to the plants reducing transpiration. Simulation with a reduced hydraulic conductivity of the

A Review on the Development of Gravitational Water Vortex Power Plant as Alternative Renewable Energy Resources

NASA Astrophysics Data System (ADS)

Rahman, M. M.; Tan, J. H.; Fadzlita, M. T.; Khairul Muzammil, A. R. Wan

2017-07-01

Gravitational water vortex power plant is a green technology that generates electricity from alternative or renewable energy source. In the vortex power plant, water is introduced into a circular basin tangentially that creates a free vortex and energy is extracted from the free vortex by using a turbine. The main advantages of this type of power plant is the generation of electricity from ultra-low hydraulic pressure and it is also environmental friendly. Since the hydraulic head requirement is as low as 1m, this type of power plant can be installed at a river or a stream to generate electricity for few houses. It is a new and not well-developed technology to harvest electricity from low pressure water energy sources. There are limited literatures available on the design, fabrication and physical geometry of the vortex turbine and generator. Past researches focus on the optimization of turbine design, inlets, outlets and basin geometry. However, there are still insufficient literatures available for the technology to proceed beyond prototyping stage. The maximum efficiency obtained by the researchers are approximately 30% while the commercial companies claimed about 50% of efficiency with 500W to 20kW of power generated. Hence, the aim of this paper is to determine the gap in the vortex power plant technology development through past works and a set of research recommendations will be developed as efforts to accelerate the development of GWVPP.

On the basically single-type excitation source of resonance in the wind tunnel and in the hydroturbine channel of a hydraulic power plant

NASA Astrophysics Data System (ADS)

Karavosov, R. K.; Prozorov, A. G.

2012-01-01

We have investigated the spectra of pressure pulsations in the near field of the open working section of the wind tunnel with a vortex flow behind the tunnel blower formed like the flow behind the hydroturbine of a hydraulic power plant. We have made a comparison between the measurement data for pressure pulsations and the air stream velocity in tunnels of the above type and in tunnels in which a large-scale vortex structure behind the blower is not formed. It has been established that the large-scale vortex formation in the incompressible medium behind the blade system in the wind tunnel is a source of narrow-band acoustic radiation capable of exciting resonance self-oscillations in the tunnel channel.

Stem photosynthesis and hydraulics are coordinated in desert plant species.

PubMed

Ávila-Lovera, Eleinis; Zerpa, Antonio J; Santiago, Louis S

2017-12-01

Coordination between stem photosynthesis and hydraulics in green-stemmed desert plants is important for understanding the physiology of stem photosynthesis and possible drought responses. Plants with photosynthetic stems have extra carbon gain that can help cope with the detrimental effects of drought. We studied photosynthetic, hydraulic and functional traits of 11 plant species with photosynthetic stems from three California desert locations. We compared relationships among traits between wet and dry seasons to test the effect of seasonality on these relationships. Finally, we compared stem trait relationships with analogous relationships in the leaf economics spectrum. We found that photosynthetic and hydraulic traits are coordinated in photosynthetic stems. The slope or intercept of all trait relationships was mediated by seasonality. The relationship between mass-based stem photosynthetic CO 2 assimilation rate (A mass ) and specific stem area (SSA; stem surface area to dry mass ratio) was statistically indistinguishable from the leaf economics spectrum. Our results indicate that photosynthetic stems behave like leaves in the coordination of multiple traits related to carbon gain, water movement and water loss. Because of the similarity of the stem A mass -SSA relationship to the leaf A mass -specific leaf area relationship, we suggest the existence of a photosynthetic stem economic spectrum. © 2017 The Authors. New Phytologist © 2017 New Phytologist Trust.

Plant xylem hydraulics: What we understand, current research, and future challenges.

PubMed

Venturas, Martin D; Sperry, John S; Hacke, Uwe G

2017-06-01

Herein we review the current state-of-the-art of plant hydraulics in the context of plant physiology, ecology, and evolution, focusing on current and future research opportunities. We explain the physics of water transport in plants and the limits of this transport system, highlighting the relationships between xylem structure and function. We describe the great variety of techniques existing for evaluating xylem resistance to cavitation. We address several methodological issues and their connection with current debates on conduit refilling and exponentially shaped vulnerability curves. We analyze the trade-offs existing between water transport safety and efficiency. We also stress how little information is available on molecular biology of cavitation and the potential role of aquaporins in conduit refilling. Finally, we draw attention to how plant hydraulic traits can be used for modeling stomatal responses to environmental variables and climate change, including drought mortality. © 2017 Institute of Botany, Chinese Academy of Sciences.

46 CFR 128.240 - Hydraulic or pneumatic power and control-materials and pressure design.

Code of Federal Regulations, 2014 CFR

2014-10-01

... Hydraulic or pneumatic power and control—materials and pressure design. (a) Each standard piping component... 46 Shipping 4 2014-10-01 2014-10-01 false Hydraulic or pneumatic power and control-materials and pressure design. 128.240 Section 128.240 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED...

46 CFR 128.240 - Hydraulic or pneumatic power and control-materials and pressure design.

Code of Federal Regulations, 2011 CFR

2011-10-01

... Hydraulic or pneumatic power and control—materials and pressure design. (a) Each standard piping component... 46 Shipping 4 2011-10-01 2011-10-01 false Hydraulic or pneumatic power and control-materials and pressure design. 128.240 Section 128.240 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED...

46 CFR 128.240 - Hydraulic or pneumatic power and control-materials and pressure design.

Code of Federal Regulations, 2012 CFR

2012-10-01

... Hydraulic or pneumatic power and control—materials and pressure design. (a) Each standard piping component... 46 Shipping 4 2012-10-01 2012-10-01 false Hydraulic or pneumatic power and control-materials and pressure design. 128.240 Section 128.240 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED...

46 CFR 128.240 - Hydraulic or pneumatic power and control-materials and pressure design.

Code of Federal Regulations, 2013 CFR

2013-10-01

... Hydraulic or pneumatic power and control—materials and pressure design. (a) Each standard piping component... 46 Shipping 4 2013-10-01 2013-10-01 false Hydraulic or pneumatic power and control-materials and pressure design. 128.240 Section 128.240 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED...

46 CFR 128.240 - Hydraulic or pneumatic power and control-materials and pressure design.

Code of Federal Regulations, 2010 CFR

2010-10-01

... Hydraulic or pneumatic power and control—materials and pressure design. (a) Each standard piping component... 46 Shipping 4 2010-10-01 2010-10-01 false Hydraulic or pneumatic power and control-materials and pressure design. 128.240 Section 128.240 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED...

Plant hydraulics and photosynthesis of 34 woody species from different successional stages of subtropical forests.

PubMed

Zhu, Shi-Dan; Song, Juan-Juan; Li, Rong-Hua; Ye, Qing

2013-04-01

It is important to understand the ecophysiological characters of plants when exploring mechanisms underlying species substitution in the process of plant succession. In the present study, we selected 34 woody species from different stages of secondary succession in subtropical forests of southern China, and measured their hydraulic conductivity, gas exchange rates, leaf nutrients and drought-tolerance traits such as xylem resistance to cavitation, turgor loss point and carbon isotope ratio. Principal component analysis revealed that early-, mid- and late-successional species were significantly separated along axis 1, which was strongly associated with hydraulic-photosynthetic coordination. In contrast to species distributed in late-successional forest, early-successional species had the highest hydraulic conductivity, net photosynthetic rates, photosynthetic nitrogen and phosphorus use efficiencies, but had the lowest photosynthetic water-use efficiency. However, changes of the measured drought-tolerance traits of the 34 species along the succession did not demonstrate a clear trend - no significant correlations between these traits and plant successional stages were found. Moreover, the trade-off between hydraulic efficiency and safety was not identified. Taken together, our results suggested that hydraulic efficiency and photosynthetic function, rather than drought tolerance, play an important role in species distributions along plant succession in subtropical forests. © 2012 Blackwell Publishing Ltd.

Leaf hydraulics and drought stress: response, recovery and survivorship in four woody temperate plant species.

PubMed

Blackman, Christopher J; Brodribb, Timothy J; Jordan, Gregory J

2009-11-01

Efficient conduction of water inside leaves is essential for leaf function, yet the hydraulic-mediated impact of drought on gas exchange remains poorly understood. Here we examine the decline and subsequent recovery of leaf water potential (Psi(leaf)), leaf hydraulic conductance (K(leaf)), and midday transpiration (E) in four temperate woody species exposed to controlled drought conditions ranging from mild to lethal. During drought the vulnerability of K(leaf) to declining Psi(leaf) varied greatly among the species sampled. Following drought, plants were rewatered and the rate of E and K(leaf) recovery was found to be strongly dependent on the severity of the drought imposed. Gas exchange recovery was strongly correlated with the relatively slow recovery of K(leaf) for three of the four species, indicating conformity to a hydraulic-stomatal limitation model of plant recovery. However, there was also a shift in the sensitivity of stomata to Psi(leaf) suggesting that the plant hormone abscisic acid may be involved in limiting the rate of stomatal reopening. The level of drought tolerance varied among the four species and was correlated with leaf hydraulic vulnerability. These results suggest that species-specific variation in hydraulic properties plays a fundamental role in steering the dynamic response of plants during recovery.

On the Potential of Hydrogen-Powered Hydraulic Pumps for Soft Robotics.

PubMed

Desbiens, Alexandre B; Bigué, Jean-Philippe Lucking; Véronneau, Catherine; Masson, Patrice; Iagnemma, Karl; Plante, Jean-Sébastien

2017-12-01

To perform untethered operations, soft robots require mesoscale power units (10-1000 W) with high energy densities. In this perspective, air-breathing combustion offers an interesting alternative to battery-powered systems, provided sufficient overall energy conversion efficiency can be reached. Implementing efficient air-breathing combustion in mesoscale soft robots is notoriously difficult, however, as it requires optimization of very small combustion actuators and simultaneous minimization of fluidic (e.g., hydraulic) losses, which are both inversely impacted by actuations speeds. To overcome such challenges, this article proposes and evaluates the potential of hydrogen-powered, hydraulic free-piston pump architecture. Experimental data, taken from two combustion-driven prototypes, reveal (1) the fundamental role of using hydrogen as the source of fuel to reduce heat losses, (2) the significant impact of compression ratio, equivalence ratio, and surface-to-volume ratio on energy conversion efficiency, and (3) the importance of load matching between combustion and fluidic transmission. In this work, a small-bore combustion actuator demonstrated a 20% efficiency and a net mean output power of 26 W, while a big-bore combustion actuator reached a substantially higher efficiency of 35% and a net mean output power of 197 W. Using the small-bore combustion actuator, the hydrogen-powered, hydraulic free-piston pump provided a 4.6% overall efficiency for a 2.34 W net mean output power, thus underlying the potential of the approach for mesoscale soft robotic applications.

Aquaporins in Coffea arabica L.: Identification, expression, and impacts on plant water relations and hydraulics.

PubMed

Miniussi, Matilda; Del Terra, Lorenzo; Savi, Tadeja; Pallavicini, Alberto; Nardini, Andrea

2015-10-01

Plant aquaporins (AQPs) are involved in the transport of water and other small solutes across cell membranes, and thus play major roles in the regulation of plant water balance, as well as in growth regulation and response to abiotic stress factors. Limited information is currently available about the presence and role of AQPs in Coffea arabica L., despite the economic importance of the species and its vulnerability to drought stress. We identified candidate AQP genes by screening a proprietary C. arabica transcriptome database, resulting in the identification of nine putative aquaporins. A phylogenetic analysis based on previously characterized AQPs from Arabidopsis thaliana and Solanum tuberosum allowed to assign the putative coffee AQP sequences to the Tonoplast (TIP) and Plasma membrane (PIP) subfamilies. The possible functional role of coffee AQPs was explored by measuring hydraulic conductance and aquaporin gene expression on leaf and root tissues of two-year-old plants (C. arabica cv. Pacamara) subjected to different experimental conditions. In a first experiment, we tested plants for root and leaf hydraulic conductance both before dawn and at mid-day, to check the eventual impact of light on AQP activity and plant hydraulics. In a second experiment, we measured plant hydraulic responses to different water stress levels as eventually affected by changes in AQPs expression levels. Our results shed light on the possible roles of AQPs in the regulation of C. arabica hydraulics and water balance, opening promising research lines to improve the sustainability of coffee cultivation under global climate change scenarios. Copyright © 2015 Elsevier Masson SAS. All rights reserved.

Regulation of leaf hydraulics: from molecular to whole plant levels.

PubMed

Prado, Karine; Maurel, Christophe

2013-01-01

The water status of plant leaves is dependent on both stomatal regulation and water supply from the vasculature to inner tissues. The present review addresses the multiple physiological and mechanistic facets of the latter process. Inner leaf tissues contribute to at least a third of the whole resistance to water flow within the plant. Physiological studies indicated that leaf hydraulic conductance (K leaf) is highly dependent on the anatomy, development and age of the leaf and can vary rapidly in response to physiological or environmental factors such as leaf hydration, light, temperature, or nutrient supply. Differences in venation pattern provide a basis for variations in K leaf during development and between species. On a short time (hour) scale, the hydraulic resistance of the vessels can be influenced by transpiration-induced cavitations, wall collapses, and changes in xylem sap composition. The extravascular compartment includes all living tissues (xylem parenchyma, bundle sheath, and mesophyll) that transport water from xylem vessels to substomatal chambers. Pharmacological inhibition and reverse genetics studies have shown that this compartment involves water channel proteins called aquaporins (AQPs) that facilitate water transport across cell membranes. In many plant species, AQPs are present in all leaf tissues with a preferential expression in the vascular bundles. The various mechanisms that allow adjustment of K leaf to specific environmental conditions include transcriptional regulation of AQPs and changes in their abundance, trafficking, and intrinsic activity. Finally, the hydraulics of inner leaf tissues can have a strong impact on the dynamic responses of leaf water potential and stomata, and as a consequence on plant carbon economy and leaf expansion growth. The manipulation of these functions could help optimize the entire plant performance and its adaptation to extreme conditions over short and long time scales.

Regulation of leaf hydraulics: from molecular to whole plant levels

PubMed Central

Prado, Karine; Maurel, Christophe

2013-01-01

The water status of plant leaves is dependent on both stomatal regulation and water supply from the vasculature to inner tissues. The present review addresses the multiple physiological and mechanistic facets of the latter process. Inner leaf tissues contribute to at least a third of the whole resistance to water flow within the plant. Physiological studies indicated that leaf hydraulic conductance (Kleaf) is highly dependent on the anatomy, development and age of the leaf and can vary rapidly in response to physiological or environmental factors such as leaf hydration, light, temperature, or nutrient supply. Differences in venation pattern provide a basis for variations in Kleaf during development and between species. On a short time (hour) scale, the hydraulic resistance of the vessels can be influenced by transpiration-induced cavitations, wall collapses, and changes in xylem sap composition. The extravascular compartment includes all living tissues (xylem parenchyma, bundle sheath, and mesophyll) that transport water from xylem vessels to substomatal chambers. Pharmacological inhibition and reverse genetics studies have shown that this compartment involves water channel proteins called aquaporins (AQPs) that facilitate water transport across cell membranes. In many plant species, AQPs are present in all leaf tissues with a preferential expression in the vascular bundles. The various mechanisms that allow adjustment of Kleaf to specific environmental conditions include transcriptional regulation of AQPs and changes in their abundance, trafficking, and intrinsic activity. Finally, the hydraulics of inner leaf tissues can have a strong impact on the dynamic responses of leaf water potential and stomata, and as a consequence on plant carbon economy and leaf expansion growth. The manipulation of these functions could help optimize the entire plant performance and its adaptation to extreme conditions over short and long time scales. PMID:23874349

Use of microalgae to remove pollutants from power plant discharges

DOEpatents

Wilde, E.W.; Benemann, J.R.; Weissman, J.C.; Tillett, D.M.

1991-04-30

A method and system are described for removing pollutants dissolved in the aqueous discharge of a plant, such as a power plant, from a body of water having known hydraulic and physicochemical characteristics, the method comprising (a) modifying the hydraulic system of the body of water including use of physical barriers to define a zone in a portion of the body of water which zone includes the discharge point and where the water has a range of physicochemical characteristics; (b) selecting a large and preferably filamentous, planktonically growing strain of algae adapted to absorb the particular pollutants and genetically dominating algae at the physicochemical characteristics of the zone; (c) establishing a colony of the selected algal strain in the zone; (d) harvesting a portion of the colony; and (e) reinoculating the zone near the discharge point with a fraction of the harvested portion. The fraction used for reinoculation can be adjusted to balance the rate of pollutant removal to the rate of pollutant discharge. 4 figures.

Novel wave power analysis linking pressure-flow waves, wave potential, and the forward and backward components of hydraulic power.

PubMed

Mynard, Jonathan P; Smolich, Joseph J

2016-04-15

Wave intensity analysis provides detailed insights into factors influencing hemodynamics. However, wave intensity is not a conserved quantity, so it is sensitive to diameter variations and is not distributed among branches of a junction. Moreover, the fundamental relation between waves and hydraulic power is unclear. We, therefore, propose an alternative to wave intensity called "wave power," calculated via incremental changes in pressure and flow (dPdQ) and a novel time-domain separation of hydraulic pressure power and kinetic power into forward and backward wave-related components (ΠP±and ΠQ±). Wave power has several useful properties:1) it is obtained directly from flow measurements, without requiring further calculation of velocity;2) it is a quasi-conserved quantity that may be used to study the relative distribution of waves at junctions; and3) it has the units of power (Watts). We also uncover a simple relationship between wave power and changes in ΠP±and show that wave reflection reduces transmitted power. Absolute values of ΠP±represent wave potential, a recently introduced concept that unifies steady and pulsatile aspects of hemodynamics. We show that wave potential represents the hydraulic energy potential stored in a compliant pressurized vessel, with spatial gradients producing waves that transfer this energy. These techniques and principles are verified numerically and also experimentally with pressure/flow measurements in all branches of a central bifurcation in sheep, under a wide range of hemodynamic conditions. The proposed "wave power analysis," encompassing wave power, wave potential, and wave separation of hydraulic power provides a potent time-domain approach for analyzing hemodynamics. Copyright © 2016 the American Physiological Society.

Does citrus leaf miner impair hydraulics and fitness of citrus host plants?

PubMed

Raimondo, Fabio; Trifilò, Patrizia; Gullo, Maria A Lo

2013-12-01

Gas exchange and hydraulic features were measured in leaves of three different Citrus species (Citrus aurantium L., Citrus limon L., Citrus  ×  paradisii Macfad) infested by Phyllocnistis citrella Staiton, with the aim to quantify the impact of this pest on leaf hydraulics and, ultimately, on plant fitness. Infested leaves were characterized by the presence on the leaf blade of typical snake-shaped mines and, in some cases, of a crumpled leaf blade. Light microscopy showed that leaf crumpling was induced by damage to the cuticular layer. In all three Citrus species examined: (a) the degree of infestation did not exceed 10% of the total surface area of infested plants; (b) control and infested leaves showed similar values of minimum diurnal leaf water potential, leaf hydraulic conductance and functional vein density; and (c) maximum diurnal values of stomatal conductance to water vapour, transpiration rate and photosynthetic rate (An) were similar in both control leaves and the green areas of infested leaves. A strong reduction of An was recorded only in mined leaf areas. Our data suggest that infestation with P. citrella does not cause conspicuous plant productivity reductions in young Citrus plants, at least not in the three Citrus species studied here.

Diversity in plant hydraulic traits explains seasonal and inter-annual variations of vegetation dynamics in seasonally dry tropical forests.

PubMed

Xu, Xiangtao; Medvigy, David; Powers, Jennifer S; Becknell, Justin M; Guan, Kaiyu

2016-10-01

We assessed whether diversity in plant hydraulic traits can explain the observed diversity in plant responses to water stress in seasonally dry tropical forests (SDTFs). The Ecosystem Demography model 2 (ED2) was updated with a trait-driven mechanistic plant hydraulic module, as well as novel drought-phenology and plant water stress schemes. Four plant functional types were parameterized on the basis of meta-analysis of plant hydraulic traits. Simulations from both the original and the updated ED2 were evaluated against 5 yr of field data from a Costa Rican SDTF site and remote-sensing data over Central America. The updated model generated realistic plant hydraulic dynamics, such as leaf water potential and stem sap flow. Compared with the original ED2, predictions from our novel trait-driven model matched better with observed growth, phenology and their variations among functional groups. Most notably, the original ED2 produced unrealistically small leaf area index (LAI) and underestimated cumulative leaf litter. Both of these biases were corrected by the updated model. The updated model was also better able to simulate spatial patterns of LAI dynamics in Central America. Plant hydraulic traits are intercorrelated in SDTFs. Mechanistic incorporation of plant hydraulic traits is necessary for the simulation of spatiotemporal patterns of vegetation dynamics in SDTFs in vegetation models. © 2016 The Authors. New Phytologist © 2016 New Phytologist Trust.

Plant hydraulic traits govern forest water use and growth

NASA Astrophysics Data System (ADS)

Matheny, Ashley; Bohrer, Gil; Fiorella, Rich; Mirfenderesgi, Golnazalsadat

2016-04-01

Biophysical controls at the leaf, stem, and root levels govern plant water acquisition and use. Suites of sometimes co-varying traits afford plants the ability to manage water stress at each of these three levels. We studied the contrasting hydraulic strategies of red oaks (Q. rubra) and red maples (A. rubrum) in northern Michigan, USA. These two species differ in stomatal regulation strategy and xylem architecture, and are thought to root at different depths. Water use was monitored through sap flux, stem water storage, and leaf water potential measurements. Depth of water acquisition was determined on the basis of stable oxygen and hydrogen isotopes from xylem water samples taken from both species. Fifteen years of bole growth records were used to compare the influence of the trees' opposing hydraulic strategies on carbon acquisition and growth. During non-limiting soil moisture conditions, transpiration from red maples typically exceeded that of red oak. However, during a 20% soil dry down, transpiration from red maples decreased by more than 80%, while transpiration from red oaks only fell by 31%. Stem water storage in red maple also declined sharply, while storage in red oaks remained nearly constant. The more consistent isotopic compositions of xylem water samples indicated that oaks can draw upon a steady, deep supply of water which red maples cannot access. Additionally, red maple bole growth correlated strongly with mean annual soil moisture, while red oak bole growth did not. These results indicate that the deeper rooting strategy of red oaks allowed the species to continue transpiration and carbon uptake during periods of intense soil water limitation, when the shallow-rooted red maples ceased transpiration. The ability to root deeply could provide an additional buffer against drought-induced mortality, which may permit some anisohydric species, like red oak, to survive hydrologic conditions that would be expected to favor survival of more isohydric

Ethylene sensitivity and relative air humidity regulate root hydraulic properties in tomato plants.

PubMed

Calvo-Polanco, Monica; Ibort, Pablo; Molina, Sonia; Ruiz-Lozano, Juan Manuel; Zamarreño, Angel María; García-Mina, Jose María; Aroca, Ricardo

2017-11-01

The effect of ethylene and its precursor ACC on root hydraulic properties, including aquaporin expression and abundance, is modulated by relative air humidity and plant sensitivity to ethylene. Relative air humidity (RH) is a main factor contributing to water balance in plants. Ethylene (ET) is known to be involved in the regulation of root water uptake and stomatal opening although its role on plant water balance under different RH is not very well understood. We studied, at the physiological, hormonal and molecular levels (aquaporins expression, abundance and phosphorylation state), the plant responses to exogenous 1-aminocyclopropane-1-carboxylic acid (ACC; precursor of ET) and 2-aminoisobutyric acid (AIB; inhibitor of ET biosynthesis), after 24 h of application to the roots of tomato wild type (WT) plants and its ET-insensitive never ripe (nr) mutant, at two RH levels: regular (50%) and close to saturation RH. Highest RH induced an increase of root hydraulic conductivity (Lp o ) of non-treated WT plants, and the opposite effect in nr mutants. The treatment with ACC reduced Lp o in WT plants at low RH and in nr plants at high RH. The application of AIB increased Lp o only in nr plants at high RH. In untreated plants, the RH treatment changed the abundance and phosphorylation of aquaporins that affected differently both genotypes according to their ET sensitivity. We show that RH is critical in regulating root hydraulic properties, and that Lp o is affected by the plant sensitivity to ET, and possibly to ACC, by regulating aquaporins expression and their phosphorylation status. These results incorporate the relationship between RH and ET in the response of Lp o to environmental changes.

Effects of plant roots on the hydraulic performance during the clogging process in mesocosm vertical flow constructed wetlands.

PubMed

Hua, G F; Zhao, Z W; Kong, J; Guo, R; Zeng, Y T; Zhao, L F; Zhu, Q D

2014-11-01

The aim of this study was to evaluate the effects of plant roots (Typha angustifolia roots) on the hydraulic performance during the clogging process from the perspective of time and space distributions in mesocosm vertical flow-constructed wetlands with coarse sand matrix. For this purpose, a pair of lab-scale experiments was conducted to compare planted and unplanted systems by measuring the effective porosity and hydraulic conductivity of the substrate within different operation periods. Furthermore, the flow pattern of the clogging process in the planted and unplanted wetland systems were evaluated by their hydraulic performance (e.g., mean residence time, short circuiting, volumetric efficiency, number of continuously stirred tank reactors, and hydraulic efficiency factor) in salt tracer experiments. The results showed that the flow conditions would change in different clogging stages, which indicated that plants played different roles related to time and space. In the early clogging stages, plant roots restricted the flow of water, while in the middle and later clogging stages, especially the later stage, growing roots opened new pore spaces in the substrate. The roots played an important role in affecting the hydraulic performance in the upper layer (0-30 cm) where the sand matrix had a larger root volume fraction. Finally, the causes of the controversy over plant roots' effects on clogging were discussed. The results helped further understand the effects of plant roots on hydraulic performance during the clogging process.

Spatial and temporal variation in plant hydraulic traits and their relevance for climate change impacts on vegetation.

PubMed

Anderegg, William R L

2015-02-01

Plant hydraulics mediate terrestrial woody plant productivity, influencing global water, carbon, and biogeochemical cycles, as well as ecosystem vulnerability to drought and climate change. While inter-specific differences in hydraulic traits are widely documented, intra-specific hydraulic variability is less well known and is important for predicting climate change impacts. Here, I present a conceptual framework for this intra-specific hydraulic trait variability, reviewing the mechanisms that drive variability and the consequences for vegetation response to climate change. I performed a meta-analysis on published studies (n = 33) of intra-specific variation in a prominent hydraulic trait - water potential at which 50% stem conductivity is lost (P50) - and compared this variation to inter-specific variability within genera and plant functional types used by a dynamic global vegetation model. I found that intra-specific variability is of ecologically relevant magnitudes, equivalent to c. 33% of the inter-specific variability within a genus, and is larger in angiosperms than gymnosperms, although the limited number of studies highlights that more research is greatly needed. Furthermore, plant functional types were poorly situated to capture key differences in hydraulic traits across species, indicating a need to approach prediction of drought impacts from a trait-based, rather than functional type-based perspective.

A Potassium-Dependent Oxygen Sensing Pathway Regulates Plant Root Hydraulics.

PubMed

Shahzad, Zaigham; Canut, Matthieu; Tournaire-Roux, Colette; Martinière, Alexandre; Boursiac, Yann; Loudet, Olivier; Maurel, Christophe

2016-09-22

Aerobic organisms survive low oxygen (O2) through activation of diverse molecular, metabolic, and physiological responses. In most plants, root water permeability (in other words, hydraulic conductivity, Lpr) is downregulated under O2 deficiency. Here, we used a quantitative genetics approach in Arabidopsis to clone Hydraulic Conductivity of Root 1 (HCR1), a Raf-like MAPKKK that negatively controls Lpr. HCR1 accumulates and is functional under combined O2 limitation and potassium (K(+)) sufficiency. HCR1 regulates Lpr and hypoxia responsive genes, through the control of RAP2.12, a key transcriptional regulator of the core anaerobic response. A substantial variation of HCR1 in regulating Lpr is observed at the Arabidopsis species level. Thus, by combinatorially integrating two soil signals, K(+) and O2 availability, HCR1 modulates the resilience of plants to multiple flooding scenarios. Copyright © 2016 Elsevier Inc. All rights reserved.

Structure and function of bordered pits: new discoveries and impacts on whole-plant hydraulic function.

PubMed

Choat, Brendan; Cobb, Alexander R; Jansen, Steven

2008-01-01

Bordered pits are cavities in the lignified cell walls of xylem conduits (vessels and tracheids) that are essential components in the water-transport system of higher plants. The pit membrane, which lies in the center of each pit, allows water to pass between xylem conduits but limits the spread of embolism and vascular pathogens in the xylem. Averaged across a wide range of species, pits account for > 50% of total xylem hydraulic resistance, indicating that they are an important factor in the overall hydraulic efficiency of plants. The structure of pits varies dramatically across species, with large differences evident in the porosity and thickness of pit membranes. Because greater porosity reduces hydraulic resistance but increases vulnerability to embolism, differences in pit structure are expected to correlate with trade-offs between efficiency and safety of water transport. However, trade-offs in hydraulic function are influenced both by pit-level differences in structure (e.g. average porosity of pit membranes) and by tissue-level changes in conduit allometry (average length, diameter) and the total surface area of pit membranes that connects vessels. In this review we address the impact of variation in pit structure on water transport in plants from the level of individual pits to the whole plant.

Nonstructural carbon dynamics are best predicted by the combination of photosynthesis and plant hydraulics during both bark beetle induced mortality and herbaceous plant response to drought

NASA Astrophysics Data System (ADS)

Ewers, B. E.; Mackay, D. S.; Guadagno, C.; Peckham, S. D.; Pendall, E.; Borkhuu, B.; Aston, T.; Frank, J. M.; Massman, W. J.; Reed, D. E.; Yarkhunova, Y.; Weinig, C.

2012-12-01

Recent work has shown that nonstructural carbon (NSC) provides both a signal and consequence of water stress in plants. The dynamics of NSC are likely not solely a result of the balance of photosynthesis and respiration (carbon starvation hypothesis) but also the availability of NSC for plant functions due to hydraulic condition. Further, plant hydraulics regulates photosynthesis both directly through stomatal conductance and indirectly through leaf water status control over leaf biochemistry. To test these hypotheses concerning NSC in response to a wide variety of plant perturbations, we used a model that combines leaf biochemical controls over photosynthesis (Farquhar model) with dynamic plant hydraulic conductance (Sperry model). This model (Terrestrial Regional Ecosystem Exchange Simulator; TREES) simulates the dynamics of NSC through a carbon budget approach that responds to plant hydraulic status. We tested TREES on two dramatically different datasets. The first dataset is from lodgepole pine and Engelmann spruce trees dying from bark beetles that carry blue-stain fungi which block xylem and cause hydraulic failure. The second data set is from Brassica rapa, a small herbaceous plant whose accessions are used in a variety of crops. The Brassica rapa plants include two parents whose circadian clock periods are different; NSC is known to provide inputs to the circadian clock likely modified by drought. Thus, drought may interact with clock control to constrain how NSC changes over the day. The Brassica rapa plants were grown in growth chamber conditions where drought was precisely controlled. The connection between these datasets is that both provide rigorous tests of our understanding of plant NSC dynamics and use similar leaf and whole plant gas exchange and NSC laboratory methods. Our results show that NSC decline (<10% in the whole plant) is less precipitous than expected from carbon starvation alone because both C uptake and use are impacted by water stress

Plant pneumatics: stem air flow is related to embolism - new perspectives on methods in plant hydraulics.

PubMed

Pereira, Luciano; Bittencourt, Paulo R L; Oliveira, Rafael S; Junior, Mauro B M; Barros, Fernanda V; Ribeiro, Rafael V; Mazzafera, Paulo

2016-07-01

Wood contains a large amount of air, even in functional xylem. Air embolisms in the xylem affect water transport and can determine plant growth and survival. Embolisms are usually estimated with laborious hydraulic methods, which can be prone to several artefacts. Here, we describe a new method for estimating embolisms that is based on air flow measurements of entire branches. To calculate the amount of air flowing out of the branch, a vacuum was applied to the cut bases of branches under different water potentials. We first investigated the source of air by determining whether it came from inside or outside the branch. Second, we compared embolism curves according to air flow or hydraulic measurements in 15 vessel- and tracheid-bearing species to test the hypothesis that the air flow is related to embolism. Air flow came almost exclusively from air inside the branch during the 2.5-min measurements and was strongly related to embolism. We propose a new embolism measurement method that is simple, effective, rapid and inexpensive, and that allows several measurements on the same branch, thus opening up new possibilities for studying plant hydraulics. © 2016 The Authors. New Phytologist © 2016 New Phytologist Trust.

Plant hydraulic strategies and their variability at high latitudes: insights from a southern Canadian boreal forest site

NASA Astrophysics Data System (ADS)

Pappas, C.; Matheny, A. M.; Maillet, J.; Baltzer, J. L.; Stephens, J.; Barr, A.; Black, T. A.; Sonnentag, O.

2016-12-01

Boreal forests cover about one third of the world's forested area with a large part of the boreal zone located in Canada. These high-latitude ecosystems respond rapidly to environmental changes. Plant water stress and the resulting drought-induced mortality has been recently hypothesised as a major driver of forest changes in western Canada. Although boreal forests often exhibit low floristic complexity, local scale abiotic heterogeneities may lead to highly variable plant functional traits and thus to diverging plant responses to environmental changes. However, detailed measurements of plant hydraulic strategies and their inter- and intra-specific variability are still lacking for these ecosystems. Here, we quantify plant water use and hydraulic strategies of black spruce (Picea mariana) and larch (Larix laricina), that are widespread in the boreal zone, at a long-term monitoring site located in central Saskatchewan (53.99° N, 105.12° W; elevation 628.94 m a.s.l.). The site is characterized by a mature black spruce overstorey that dominates the landscape with few larch individuals. The ground cover consists mainly of mosses with some peat moss and lichens over a rich soil organic layer. Tree-level sap flux density, measured with Granier-style thermal dissipation probes (N=39), and concurrently recorded radial stem dynamics, measured with high frequency dendrometers (N=13), are used to quantify plant hydraulic functioning during the 2016 growing season. Hydrometeorological measurements, including soil moisture and micrometeorological data, are used to describe environmental constraints in plant water use. Tree-level dynamics are then integrated to the landscape and compared with ecosystem-level evapotranspiration measurements from an adjacent eddy-covariance flux tower. This experimental design allows us to quantify the main environmental drivers that shape plant hydraulic strategies in this southern boreal zone and to provide new insights into the inter- and

Wood anatomy and plant hydraulics in a changing climate

Treesearch

William R.L. Anderegg; Frederick C. Meinzer

2015-01-01

Due to their hydraulic system that allows them to transport water from the soil to leaves, woody plants have become incredibly successful in terrestrial ecosystems since their evolution ~400 million years ago (Hartmann 2011). This vascular system lets trees conduct water from the soil up to more than 100 m (Koch et al. 2004), allowing trees to compete for light and...

Nuclear power plant 5,000 to 10,000 kilowatts

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

Not Available

The purpose of this proposal is to present a suggested program for the development of an Aqueous Homogeneous Reactor Power Plant for the production of power in the 5000 to 10,000 kilowatt range under the terms of the Atomic Energy Commission's invitation of September 21, 1955. It envisions a research and development program prior to finalizing fabricating commitments of full scale components for the purpose of proving mechanical and hydraulic operating and chemical processing feasibility with the expectation that such preliminary effort will assure the contruction of the reactor at the lowest cost and successful operation at the earliest date.more » It proposes the construction of a reactor for an eventual net electrical output of ten megawatts but initially in conjunction with a five megawatt turbo-generating unit. This unit would be constructed at the site of the existing Hersey diesel generating plant of the Wolverine Electric Cooperative approximately ten miles north of Big Rapids, Michigan.« less

Co-optimal distribution of leaf nitrogen and hydraulic conductance in plant canopies.

PubMed

Peltoniemi, Mikko S; Duursma, Remko A; Medlyn, Belinda E

2012-05-01

Leaf properties vary significantly within plant canopies, due to the strong gradient in light availability through the canopy, and the need for plants to use resources efficiently. At high light, photosynthesis is maximized when leaves have a high nitrogen content and water supply, whereas at low light leaves have a lower requirement for both nitrogen and water. Studies of the distribution of leaf nitrogen (N) within canopies have shown that, if water supply is ignored, the optimal distribution is that where N is proportional to light, but that the gradient of N in real canopies is shallower than the optimal distribution. We extend this work by considering the optimal co-allocation of nitrogen and water supply within plant canopies. We developed a simple 'toy' two-leaf canopy model and optimized the distribution of N and hydraulic conductance (K) between the two leaves. We asked whether hydraulic constraints to water supply can explain shallow N gradients in canopies. We found that the optimal N distribution within plant canopies is proportional to the light distribution only if hydraulic conductance, K, is also optimally distributed. The optimal distribution of K is that where K and N are both proportional to incident light, such that optimal K is highest to the upper canopy. If the plant is constrained in its ability to construct higher K to sun-exposed leaves, the optimal N distribution does not follow the gradient in light within canopies, but instead follows a shallower gradient. We therefore hypothesize that measured deviations from the predicted optimal distribution of N could be explained by constraints on the distribution of K within canopies. Further empirical research is required on the extent to which plants can construct optimal K distributions, and whether shallow within-canopy N distributions can be explained by sub-optimal K distributions.

Mechanical Failure of Fine Root Cortical Cells Initiates Plant Hydraulic Decline during Drought.

PubMed

Cuneo, Italo F; Knipfer, Thorsten; Brodersen, Craig R; McElrone, Andrew J

2016-11-01

Root systems perform the crucial task of absorbing water from the soil to meet the demands of a transpiring canopy. Roots are thought to operate like electrical fuses, which break when carrying an excessive load under conditions of drought stress. Yet the exact site and sequence of this dysfunction in roots remain elusive. Using in vivo x-ray computed microtomography, we found that drought-induced mechanical failure (i.e. lacunae formation) in fine root cortical cells is the initial and primary driver of reduced fine root hydraulic conductivity (Lp r ) under mild to moderate drought stress. Cortical lacunae started forming under mild drought stress (-0.6 MPa Ψ stem ), coincided with a dramatic reduction in Lp r , and preceded root shrinkage or significant xylem embolism. Only under increased drought stress was embolism formation observed in the root xylem, and it appeared first in the fine roots (50% loss of hydraulic conductivity [P 50 ] reached at -1.8 MPa) and then in older, coarse roots (P 50 = -3.5 MPa). These results suggest that cortical cells in fine roots function like hydraulic fuses that decouple plants from drying soil, thus preserving the hydraulic integrity of the plant's vascular system under early stages of drought stress. Cortical lacunae formation led to permanent structural damage of the root cortex and nonrecoverable Lp r , pointing to a role in fine root mortality and turnover under drought stress. © 2016 American Society of Plant Biologists. All Rights Reserved.

Use of Plant Hydraulic Theory to Predict Ecosystem Fluxes Across Mountainous Gradients in Environmental Controls and Insect Disturbances

NASA Astrophysics Data System (ADS)

Ewers, B. E.; Pendall, E.; Reed, D. E.; Barnard, H. R.; Whitehouse, F.; Frank, J. M.; Massman, W. J.; Brooks, P. D.; Biederman, J. A.; Harpold, A. A.; Naithani, K. J.; Mitra, B.; Mackay, D. S.; Norton, U.; Borkhuu, B.

2011-12-01

While mountainous areas are critical for providing numerous ecosystem benefits at the regional scale, the strong gradients in environmental controls make predictions difficult. A key part of the problem is quantifying and predicting the feedback between mountain gradients and plant function which then controls ecosystem cycling. The emerging theory of plant hydraulics provides a rigorous yet simple platform from which to generate testable hypotheses and predictions of ecosystem pools and fluxes. Plant hydraulic theory predicts that plant controls over carbon, water, energy and nutrient fluxes can be derived from the limitation of plant water transport from the soil through xylem and out of stomata. In addition, the limit to plant water transport can be predicted by combining plant structure (e.g. xylem diameters or root-to-shoot ratios) and plant function (response of stomatal conductance to vapor pressure deficit or root vulnerability to cavitation). We evaluate the predictions of the plant hydraulic theory by testing it against data from a mountain gradient encompassing sagebrush steppe through subalpine forests (2700 to 3400 m). We further test the theory by predicting the carbon, water and nutrient exchanges from several coniferous trees in the same gradient that are dying from xylem dysfunction caused by blue-stain fungi carried by bark beetles. The common theme of both of these data sets is a change in water limitation caused by either changing precipitation along the mountainous gradient or lack of access to soil water from xylem-occluding fungi. Across all of the data sets which range in scale from individual plants to hillslopes, the data fit the predictions of plant hydraulic theory. Namely, there was a proportional tradeoff between the reference canopy stomatal conductance to water vapor and the sensitivity of that conductance to vapor pressure deficit that quantitatively fits the predictions of plant hydraulic theory. Incorporating this result into

A synthesis of the effects of atmospheric carbon dioxide enrichment on plant hydraulics: implications for whole-plant water use efficiency and resistance to drought.

PubMed

Domec, Jean-Christophe; Smith, Duncan D; McCulloh, Kate A

2017-06-01

Here, we summarize studies on the effects of elevated [CO 2 ] (CO 2 e ) on the structure and function of plant hydraulic architecture and explore the implications of those changes using a model. Changes in conduit diameter and hydraulic conductance due to CO 2 e vary among species. Ring-porous species tend towards an increase in conduit size and consequently conductivity. The effect in diffuse-porous species is much more limited. In conifers, the results are mixed, some species show minor changes in xylem structure, while other studies found increases in tracheid density and diameter. Non-woody plants generally exhibited the reverse pattern with narrower conduits and lower hydraulic conductivity under CO 2 e . Further, changes in drought-resistance traits suggest that non-woody plants were the most affected by CO 2 e , which may permit them to better resist drought-induced embolism under future conditions. Due to their complexity, acclimation in hydraulic traits in response to CO 2 e is difficult to interpret when relying solely on measurements. When we examined how the observed tissues-specific trends might alter plant function, our modelling results suggest that these hydraulic changes would lead to reduced conductance and more frequent drought stress in trees that develop under CO 2 e with a more pronounced effect in isohydric than in anisohydric species. © 2016 John Wiley & Sons Ltd.

Constant-Pressure Hydraulic Pump

NASA Technical Reports Server (NTRS)

Galloway, C. W.

1982-01-01

Constant output pressure in gas-driven hydraulic pump would be assured in new design for gas-to-hydraulic power converter. With a force-multiplying ring attached to gas piston, expanding gas would apply constant force on hydraulic piston even though gas pressure drops. As a result, pressure of hydraulic fluid remains steady, and power output of the pump does not vary.

Hydraulic resistance of a plant root to water-uptake: A slender-body theory.

PubMed

Chen, Kang Ping

2016-05-07

A slender-body theory for calculating the hydraulic resistance of a single plant root is developed. The work provides an in-depth discussion on the procedure and the assumptions involved in calculating a root׳s internal hydraulic resistance as well as the physical and the mathematical aspects of the external three-dimensional flow around the tip of a root in a saturated soil and how this flow pattern enhances uptake and reduces hydraulic resistance. Analytical solutions for the flux density distribution on the stele-cortex interface, local water-uptake profile inside the stele core, the overall water-uptake at the base of the stele, and the total hydraulic resistance of a root are obtained in the slender-body limit. It is shown that a key parameter controlling a root's hydraulic resistance is the dimensionless axial conductivity in the stele, which depends on the permeabilities of the stele and the cortex as well as the root's radial and axial dimensions. Three-dimensional tip effect reduces a root's hydraulic resistance by as much as 36% when compared to the radial flow theory of Landsberg and Fowkes. In addition, the total hydraulic resistance cannot be generally decomposed into the direct sum of a radial resistance and an axial resistance. Copyright © 2016 Elsevier Ltd. All rights reserved.

Hydraulic redistribution: limitations for plants in saline soils.

PubMed

Bazihizina, Nadia; Veneklaas, Erik J; Barrett-Lennard, Edward G; Colmer, Timothy D

2017-10-01

Hydraulic redistribution (HR), the movement of water from wet to dry patches in the soil via roots, occurs in different ecosystems and plant species. By extension of the principle that HR is driven by gradients in soil water potential, HR has been proposed to occur for plants in saline soils. Despite the inherent spatial patchiness and salinity gradients in these soils, the lack of direct evidence of HR in response to osmotic gradients prompted us to ask the question: are there physical or physiological constraints to HR for plants in saline environments? We propose that build-up of ions in the root xylem sap and in the leaf apoplast, with the latter resulting in a large predawn disequilibrium of water potential in shoots compared with roots and soil, would both impede HR. We present a conceptual model that illustrates how processes in root systems in heterogeneous salinity with water potential gradients, even if equal to those in non-saline soils, will experience a dampened magnitude of water potential gradients in the soil-plant continuum, minimizing or preventing HR. Finally, we provide an outlook for understanding the relevance of HR for plants in saline environments by addressing key research questions on plant salinity tolerance. © 2017 John Wiley & Sons Ltd.

CFD Aided Design and Production of Hydraulic Turbines

NASA Astrophysics Data System (ADS)

Kaplan, Alper; Cetinturk, Huseyin; Demirel, Gizem; Ayli, Ece; Celebioglu, Kutay; Aradag, Selin; ETU Hydro Research Center Team

2014-11-01

Hydraulic turbines are turbo machines which produce electricity from hydraulic energy. Francis type turbines are the most common one in use today. The design of these turbines requires high engineering effort since each turbine is tailor made due to different head and discharge. Therefore each component of the turbine is designed specifically. During the last decades, Computational Fluid Dynamics (CFD) has become very useful tool to predict hydraulic machinery performance and save time and money for designers. This paper describes a design methodology to optimize a Francis turbine by integrating theoretical and experimental fundamentals of hydraulic machines and commercial CFD codes. Specific turbines are designed and manufactured with the help of a collaborative CFD/CAD/CAM methodology based on computational fluid dynamics and five-axis machining for hydraulic electric power plants. The details are presented in this study. This study is financially supported by Turkish Ministry of Development.

Estimating drought induced tree mortality in the Amazon rainforest: A simulation study with a focus on plant hydraulic processes

NASA Astrophysics Data System (ADS)

Papastefanou, P.; Fleischer, K.; Hickler, T.; Grams, T.; Lapola, D.; Quesada, C. A.; Zang, C.; Rammig, A.

2017-12-01

The Amazon basin was recently hit by severe drought events that were unprecedented in their severity and spatial extent, e.g. during 2005, 2010 and 2015/2016. Significant amounts of biomass were lost, turning large parts of the rainforest from a carbon sink into a carbon source. It is assumed that drought-induced tree mortality from hydraulic failure played an important role during these events and may become more frequent in the Amazon region in the future. Many state-of-the-art dynamic vegetation models do not include plant hydraulic processes and fail to reproduce observed rainforest responses to drought events, such as e.g. increased tree mortality. We address this research gap by developing a simple plant-hydraulic module for the dynamic vegetation model LPJ-GUESS. This plant-hydraulic module uses leaf water potential and cavitation as baseline processes to simulate tree mortality under drought stress. Furthermore, we introduce different plant strategies in the model, which describe e.g. differences in the stomatal regulation under drought stress. To parameterize and evaluate our hydraulic module, we use a set of available observational data from the Amazon region. We apply our model to the Amazon Basin and highlight similarities and differences across other measured and predicted drought responses, e.g. extrapolated observations and data derived from satellite measurements. Our results highlight the importance of including plant hydraulic processes in dynamic vegetation models to correctly predict vegetation dynamics under drought stress and show major differences on the vegetation dynamics depending on the selected plant strategies. We also identify gaps in process understanding of the triggering factors, the extent and the consequences of drought responses that hampers our ability to predict potential impact of future drought events on the Amazon rainforest.

Noninvasive assessment of vascular function and hydraulic power and efficiency in pediatric Fontan patients.

PubMed

Myers, Kimberley A; Leung, Mande T; Terri Potts, M; Potts, James E; Sandor, George G S

2013-10-01

Invasive studies have shown that children with Fontan palliation have abnormal arterial stiffness, impedance, and hydraulic power and efficiency. The aim of this study was to assess these indexes noninvasively in a cohort of children with Fontan circulation using Doppler echocardiography and compare their results with those of healthy peers. This was a case-control study of 22 Fontan patients and 31 healthy control children. Using standard two-dimensional, M-mode, and Doppler echocardiographic imaging and carotid artery applanation tonometry, aortic flows, dimensions, and pulse-wave velocity were measured, and vascular impedance and arterial stiffness were calculated. Hydraulic power and efficiency were calculated from standard fluid dynamics formulae. The median age was similar between groups. Stroke volume index (39 vs 39 mL/min/m(2)) and cardiac index (2.6 vs 2.5 L/min/m(2)) were similar. Aortic cross-sectional area (3.3 vs 2.8 cm(2)), peak aortic flow (302 vs 261 cm(3)/sec), and myocardial performance index (0.47 vs 0.25) were higher and ejection fraction (50% vs 66%) was lower in Fontan patients. Input impedance (61 vs 83 dyne · sec/cm(5)/m(2)) was lower in Fontan patients. Pulse-wave velocity (488 vs 364 cm/sec), elastic pressure-strain modulus (305 vs 263 torr), and stiffness index (4.15 vs 3.04) were higher in Fontan patients. Total arterial compliance (1.29 vs 1.32 mL/torr/m(2)) and mean power (606 vs 527 mW/m(2)) were similar and total hydraulic power (716 vs 627 mW/m(2)) was higher in Fontan patients. Efficiency and the power cost per unit of forward flow were similar. Despite stiffer aortas, Fontan patients generate more hydraulic power associated with decreased ventricular function to achieve a similar hydraulic efficiency. In Fontan patients, therapy that is given to improve ventricular function may need to target vascular stiffness as well. This technique may be used to monitor the efficacy of therapeutic interventions. Copyright © 2013 American

Traits, properties, and performance: how woody plants combine hydraulic and mechanical functions in a cell, tissue, or whole plant.

PubMed

Lachenbruch, Barbara; McCulloh, Katherine A

2014-12-01

This review presents a framework for evaluating how cells, tissues, organs, and whole plants perform both hydraulic and mechanical functions. The morphological alterations that affect dual functionality are varied: individual cells can have altered morphology; tissues can have altered partitioning to functions or altered cell alignment; and organs and whole plants can differ in their allocation to different tissues, or in the geometric distribution of the tissues they have. A hierarchical model emphasizes that morphological traits influence the hydraulic or mechanical properties; the properties, combined with the plant unit's environment, then influence the performance of that plant unit. As a special case, we discuss the mechanisms by which the proxy property wood density has strong correlations to performance but without direct causality. Traits and properties influence multiple aspects of performance, and there can be mutual compensations such that similar performance occurs. This compensation emphasizes that natural selection acts on, and a plant's viability is determined by, its performance, rather than its contributing traits and properties. Continued research on the relationships among traits, and on their effects on multiple aspects of performance, will help us better predict, manage, and select plant material for success under multiple stresses in the future. © 2014 The Authors. New Phytologist © 2014 New Phytologist Trust.

Responses of Woody Plant Functional Traits to Nitrogen Addition: A Meta-Analysis of Leaf Economics, Gas Exchange, and Hydraulic Traits.

PubMed

Zhang, Hongxia; Li, Weibin; Adams, Henry D; Wang, Anzhi; Wu, Jiabing; Jin, Changjie; Guan, Dexin; Yuan, Fenghui

2018-01-01

Atmospheric nitrogen (N) deposition has been found to significantly affect plant growth and physiological performance in terrestrial ecosystems. Many individual studies have investigated how N addition influences plant functional traits, however these investigations have usually been limited to a single species, and thereby do not allow derivation of general patterns or underlying mechanisms. We synthesized data from 56 papers and conducted a meta-analysis to assess the general responses of 15 variables related to leaf economics, gas exchange, and hydraulic traits to N addition among 61 woody plant species, primarily from temperate and subtropical regions. Results showed that under N addition, leaf area index (+10.3%), foliar N content (+7.3%), intrinsic water-use efficiency (+3.1%) and net photosynthetic rate (+16.1%) significantly increased, while specific leaf area, stomatal conductance, and transpiration rate did not change. For plant hydraulics, N addition significantly increased vessel diameter (+7.0%), hydraulic conductance in stems/shoots (+6.7%), and water potential corresponding to 50% loss of hydraulic conductivity ( P 50 , +21.5%; i.e., P 50 became less negative), while water potential in leaves (-6.7%) decreased (became more negative). N addition had little effect on vessel density, hydraulic conductance in leaves and roots, or water potential in stems/shoots. N addition had greater effects on gymnosperms than angiosperms and ammonium nitrate fertilization had larger effects than fertilization with urea, and high levels of N addition affected more traits than low levels. Our results demonstrate that N addition has coupled effects on both carbon and water dynamics of woody plants. Increased leaf N, likely fixed in photosynthetic enzymes and pigments leads to higher photosynthesis and water use efficiency, which may increase leaf growth, as reflected in LAI results. These changes appear to have downstream effects on hydraulic function through increases

The correlations and sequence of plant stomatal, hydraulic, and wilting responses to drought

PubMed Central

Bartlett, Megan K.; Klein, Tamir; Jansen, Steven; Choat, Brendan; Sack, Lawren

2016-01-01

Climate change is expected to exacerbate drought for many plants, making drought tolerance a key driver of species and ecosystem responses. Plant drought tolerance is determined by multiple traits, but the relationships among traits, either within individual plants or across species, have not been evaluated for general patterns across plant diversity. We synthesized the published data for stomatal closure, wilting, declines in hydraulic conductivity in the leaves, stems, and roots, and plant mortality for 262 woody angiosperm and 48 gymnosperm species. We evaluated the correlations among the drought tolerance traits across species, and the general sequence of water potential thresholds for these traits within individual plants. The trait correlations across species provide a framework for predicting plant responses to a wide range of water stress from one or two sampled traits, increasing the ability to rapidly characterize drought tolerance across diverse species. Analyzing these correlations also identified correlations among the leaf and stem hydraulic traits and the wilting point, or turgor loss point, beyond those expected from shared ancestry or independent associations with water stress alone. Further, on average, the angiosperm species generally exhibited a sequence of drought tolerance traits that is expected to limit severe tissue damage during drought, such as wilting and substantial stem embolism. This synthesis of the relationships among the drought tolerance traits provides crucial, empirically supported insight into representing variation in multiple traits in models of plant and ecosystem responses to drought. PMID:27807136

The correlations and sequence of plant stomatal, hydraulic, and wilting responses to drought.

PubMed

Bartlett, Megan K; Klein, Tamir; Jansen, Steven; Choat, Brendan; Sack, Lawren

2016-11-15

Climate change is expected to exacerbate drought for many plants, making drought tolerance a key driver of species and ecosystem responses. Plant drought tolerance is determined by multiple traits, but the relationships among traits, either within individual plants or across species, have not been evaluated for general patterns across plant diversity. We synthesized the published data for stomatal closure, wilting, declines in hydraulic conductivity in the leaves, stems, and roots, and plant mortality for 262 woody angiosperm and 48 gymnosperm species. We evaluated the correlations among the drought tolerance traits across species, and the general sequence of water potential thresholds for these traits within individual plants. The trait correlations across species provide a framework for predicting plant responses to a wide range of water stress from one or two sampled traits, increasing the ability to rapidly characterize drought tolerance across diverse species. Analyzing these correlations also identified correlations among the leaf and stem hydraulic traits and the wilting point, or turgor loss point, beyond those expected from shared ancestry or independent associations with water stress alone. Further, on average, the angiosperm species generally exhibited a sequence of drought tolerance traits that is expected to limit severe tissue damage during drought, such as wilting and substantial stem embolism. This synthesis of the relationships among the drought tolerance traits provides crucial, empirically supported insight into representing variation in multiple traits in models of plant and ecosystem responses to drought.

Quantitative Hydraulic Models Of Early Land Plants Provide Insight Into Middle Paleozoic Terrestrial Paleoenvironmental Conditions

NASA Astrophysics Data System (ADS)

Wilson, J. P.; Fischer, W. W.

2010-12-01

Fossil plants provide useful proxies of Earth’s climate because plants are closely connected, through physiology and morphology, to the environments in which they lived. Recent advances in quantitative hydraulic models of plant water transport provide new insight into the history of climate by allowing fossils to speak directly to environmental conditions based on preserved internal anatomy. We report results of a quantitative hydraulic model applied to one of the earliest terrestrial plants preserved in three dimensions, the ~396 million-year-old vascular plant Asteroxylon mackei. This model combines equations describing the rate of fluid flow through plant tissues with detailed observations of plant anatomy; this allows quantitative estimates of two critical aspects of plant function. First and foremost, results from these models quantify the supply of water to evaporative surfaces; second, results describe the ability of plant vascular systems to resist tensile damage from extreme environmental events, such as drought or frost. This approach permits quantitative comparisons of functional aspects of Asteroxylon with other extinct and extant plants, informs the quality of plant-based environmental proxies, and provides concrete data that can be input into climate models. Results indicate that despite their small size, water transport cells in Asteroxylon could supply a large volume of water to the plant's leaves--even greater than cells from some later-evolved seed plants. The smallest Asteroxylon tracheids have conductivities exceeding 0.015 m^2 / MPa * s, whereas Paleozoic conifer tracheids do not reach this threshold until they are three times wider. However, this increase in conductivity came at the cost of little to no adaptations for transport safety, placing the plant’s vegetative organs in jeopardy during drought events. Analysis of the thickness-to-span ratio of Asteroxylon’s tracheids suggests that environmental conditions of reduced relative

An Integrated View of Whole-Tree Hydraulic Architecture. Does Stomatal or Hydraulic Conductance Determine Whole Tree Transpiration?

PubMed Central

Rodríguez-Gamir, Juan; Primo-Millo, Eduardo; Forner-Giner, María Ángeles

2016-01-01

Hydraulic conductance exerts a strong influence on many aspects of plant physiology, namely: transpiration, CO2 assimilation, growth, productivity or stress response. However we lack full understanding of the contribution of root or shoot water transport capacity to the total water balance, something which is difficult to study in trees. Here we tested the hypothesis that whole plant hydraulic conductance modulates plant transpiration using two different seedlings of citrus rootstocks, Poncirus trifoliata (L.) Raf. and Cleopatra mandarin (Citrus reshni Hort ex Tan.). The two genotypes presented important differences in their root or shoot hydraulic conductance contribution to whole plant hydraulic conductance but, even so, water balance proved highly dependent on whole plant conductance. Further, we propose there is a possible equilibrium between root and shoot hydraulic conductance, similar to that between shoot and root biomass production, which could be related with xylem anatomy. PMID:27223695

Horizontal steam generator thermal-hydraulics

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

Ubra, O.; Doubek, M.

1995-09-01

Horizontal steam generators are typical components of nuclear power plants with pressure water reactor type VVER. Thermal-hydraulic behavior of horizontal steam generators is very different from the vertical U-tube steam generator, which has been extensively studied for several years. To contribute to the understanding of the horizontal steam generator thermal-hydraulics a computer program for 3-D steady state analysis of the PGV-1000 steam generator has been developed. By means of this computer program, a detailed thermal-hydraulic and thermodynamic study of the horizontal steam generator PGV-1000 has been carried out and a set of important steam generator characteristics has been obtained. Themore » 3-D distribution of the void fraction and 3-D level profile as functions of load and secondary side pressure have been investigated and secondary side volumes and masses as functions of load and pressure have been evaluated. Some of the interesting results of calculations are presented in the paper.« less

Energy conservation strategy in Hydraulic Power Packs using Variable Frequency Drive IOP Conference Series: Materials Science and Engineering

NASA Astrophysics Data System (ADS)

Ramesh, S.; Ashok, S. Denis; Nagaraj, Shanmukha; Reddy, M. Lohith Kumar; Naulakha, Niranjan Kumar; Adithyakumar, C. R.

2018-02-01

At present, energy consumption is to such an extent that if the same trend goes on then in the future at some point of time, the energy sources will all be exploited. Energy conservation in a hydraulic power pack refers to the reduction in the energy consumed by the power pack. Many experiments have been conducted to reduce the energy consumption and one of those methods is by introducing a variable frequency drive. The main objective of the present work is to reduce the energy consumed by the hydraulic power pack using variable frequency drive. Variable Frequency drive is used to vary the speed of the motor by receiving electrical signals from the pressure switch which acts as the feedback system. Using this concept, the speed of the motor can be varied between the specified limits. In the present work, a basic hydraulic power pack and a variable frequency drive based hydraulic power pack were designed and compared both of them with the results obtained. The comparison was based on the power consumed, rise in temperature, noise levels, and flow of oil through pressure relief valve, total oil flow during loading cycle. By comparing both the circuits, it is found that for the proposed system, consumption of power reduces by 78.4% and is as powerful as the present system.

Concentrating Solar Power Projects - Saguaro Power Plant | Concentrating

Science.gov Websites

Solar Power | NREL Saguaro Power Plant This page provides information on Saguaro, a concentrating solar power (CSP) project, with data organized by background, participants, and power plant configuration. Status Date: April 14, 2017 Project Overview Project Name: Saguaro Power Plant Country: United

Proceedings of the 7th International Meeting on Nuclear Reactor Thermal-Hydraulics NURETH-7. Sessions 17-24

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

Block, R.C.; Feiner, F.

1995-09-01

Technical papers accepted for presentation at the Seventh International Topical Meeting on Nuclear Reactor Thermal-Hydraulics are included in the present Proceedings. Except for the invited papers in the plenary session, all other papers are contributed papers. The topics of the meeting encompass all major areas of nuclear thermal-hydraulics, including analytical and experimental works on the fundamental mechanisms of fluid flow and heat transfer, the development of advanced mathematical and numerical methods, and the application of advancements in the field in the development of novel reactor concepts. Because of the complex nature of nuclear reactors and power plants, several papers dealmore » with the combined issues of thermal-hydraulics and reactor/power-plant safety, core neutronics and/or radiation. The participation in the conference by the authors from several countries and four continents makes the Proceedings a comprehensive review of the recent progress in the field of nuclear reactor thermal-hydraulics worldwide. Individual papers have been cataloged separately.« less

Functional convergence in hydraulic architecture and water relations of tropical savanna trees: from leaf to whole plant.

Treesearch

S.J. Bucci; G. Goldstein; F.C. Meinzer; F.G. Scholz; A.C. France; M. Bustamante

2004-01-01

Functional convergence in hydraulic architecture and water relations, and potential trade-offs in resource allocation were investigated in six dominant neotropical savanna tree species from central Brazil during the peak of the dry season. Common relationships between wood density and several aspects of plant water relations and hydraulic architecture were observed....

Energy comparison between solar thermal power plant and photovoltaic power plant

NASA Astrophysics Data System (ADS)

Novosel, Urška; Avsec, Jurij

2017-07-01

The combined use of renewable energy and alternative energy systems and better efficiency of energy devices is a promising approach to reduce effects due to global warming in the world. On the basis of first and second law of thermodynamics we could optimize the processes in the energy sector. The presented paper shows the comparison between solar thermal power plant and photovoltaic power plant in terms of energy, exergy and life cycle analysis. Solar thermal power plant produces electricity with basic Rankine cycle, using solar tower and solar mirrors to produce high fluid temperature. Heat from the solar system is transferred by using a heat exchanger to Rankine cycle. Both power plants produce hydrogen via electrolysis. The paper shows the global efficiency of the system, regarding production of the energy system.

Modelling and optimization of transient processes in line focusing power plants with single-phase heat transfer medium

NASA Astrophysics Data System (ADS)

Noureldin, K.; González-Escalada, L. M.; Hirsch, T.; Nouri, B.; Pitz-Paal, R.

2016-05-01

A large number of commercial and research line focusing solar power plants are in operation and under development. Such plants include parabolic trough collectors (PTC) or linear Fresnel using thermal oil or molten salt as the heat transfer medium (HTM). However, the continuously varying and dynamic solar condition represent a big challenge for the plant control in order to optimize its power production and to keep the operation safe. A better understanding of the behaviour of such power plants under transient conditions will help reduce defocusing instances, improve field control, and hence, increase the energy yield and confidence in this new technology. Computational methods are very powerful and cost-effective tools to gain such understanding. However, most simulation models described in literature assume equal mass flow distributions among the parallel loops in the field or totally decouple the flow and thermal conditions. In this paper, a new numerical model to simulate a whole solar field with single-phase HTM is described. The proposed model consists of a hydraulic part and a thermal part that are coupled to account for the effect of the thermal condition of the field on the flow distribution among the parallel loops. The model is specifically designed for large line-focusing solar fields offering a high degree of flexibility in terms of layout, condition of the mirrors, and spatially resolved DNI data. Moreover, the model results have been compared to other simulation tools, as well as experimental and plant data, and the results show very good agreement. The model can provide more precise data to the control algorithms to improve the plant control. In addition, short-term and accurate spatially discretized DNI forecasts can be used as input to predict the field behaviour in-advance. In this paper, the hydraulic and thermal parts, as well as the coupling procedure, are described and some validation results and results of simulating an example field are

Variable-Displacement Hydraulic Drive Unit

NASA Technical Reports Server (NTRS)

Lang, D. J.; Linton, D. J.; Markunas, A.

1986-01-01

Hydraulic power controlled through multiple feedback loops. In hydraulic drive unit, power closely matched to demand, thereby saving energy. Hydraulic flow to and from motor adjusted by motor-control valve connected to wobbler. Wobbler angle determines motor-control-valve position, which in turn determines motor displacement. Concept applicable to machine tools, aircraft controls, and marine controls.

NUCLEAR POWER PLANT

DOEpatents

Carter, J.C.; Armstrong, R.H.; Janicke, M.J.

1963-05-14

A nuclear power plant for use in an airless environment or other environment in which cooling is difficult is described. The power plant includes a boiling mercury reactor, a mercury--vapor turbine in direct cycle therewith, and a radiator for condensing mercury vapor. (AEC)

Prolonged experimental drought reduces plant hydraulic conductance and transpiration and increases mortality in a piñon–juniper woodland

PubMed Central

Pangle, Robert E; Limousin, Jean-Marc; Plaut, Jennifer A; Yepez, Enrico A; Hudson, Patrick J; Boutz, Amanda L; Gehres, Nathan; Pockman, William T; McDowell, Nate G

2015-01-01

Plant hydraulic conductance (ks) is a critical control on whole-plant water use and carbon uptake and, during drought, influences whether plants survive or die. To assess long-term physiological and hydraulic responses of mature trees to water availability, we manipulated ecosystem-scale water availability from 2007 to 2013 in a piñon pine (Pinus edulis) and juniper (Juniperus monosperma) woodland. We examined the relationship between ks and subsequent mortality using more than 5 years of physiological observations, and the subsequent impact of reduced hydraulic function and mortality on total woody canopy transpiration (EC) and conductance (GC). For both species, we observed significant reductions in plant transpiration (E) and ks under experimentally imposed drought. Conversely, supplemental water additions increased E and ks in both species. Interestingly, both species exhibited similar declines in ks under the imposed drought conditions, despite their differing stomatal responses and mortality patterns during drought. Reduced whole-plant ks also reduced carbon assimilation in both species, as leaf-level stomatal conductance (gs) and net photosynthesis (An) declined strongly with decreasing ks. Finally, we observed that chronically low whole-plant ks was associated with greater canopy dieback and mortality for both piñon and juniper and that subsequent reductions in woody canopy biomass due to mortality had a significant impact on both daily and annual canopy EC and GC. Our data indicate that significant reductions in ks precede drought-related tree mortality events in this system, and the consequence is a significant reduction in canopy gas exchange and carbon fixation. Our results suggest that reductions in productivity and woody plant cover in piñon–juniper woodlands can be expected due to reduced plant hydraulic conductance and increased mortality of both piñon pine and juniper under anticipated future conditions of more frequent and persistent

Hydraulics and gas exchange recover more rapidly from severe drought stress in small pot-grown grapevines than in field-grown plants.

PubMed

Romero, Pascual; Botía, Pablo; Keller, Markus

2017-09-01

Modifications of plant hydraulics and shoot resistances (R shoot ) induced by water withholding followed by rewatering, and their relationships with plant water status, leaf gas exchange and water use efficiency at the leaf level, were investigated in pot-grown and field-grown, own-rooted Syrah grapevines in an arid climate. Water stress induced anisohydric behavior, gradually reducing stomatal conductance (g s ) and leaf photosynthesis (A) in response to decreasing midday stem water potential (Ψ s ). Water stress also rapidly increased intrinsic water-use efficiency (A/g s ); this effect persisted for many days after rewatering. Whole-plant (K plant ), canopy (K canopy ), shoot (K shoot ) and leaf (K leaf ) hydraulic conductances decreased during water stress, in tune with the gradual decrease in Ψ s , leaf gas exchange and whole plant water use. Water-stressed vines also had a lower Ψ gradient between stem and leaf (ΔΨ l ), which was correlated with lower leaf transpiration rate (E). E and ΔΨ l increased with increasing vapour pressure deficit (VPD) in non-stressed control vines but not in stressed vines. Perfusion of xylem-mobile dye showed that water flow to petioles and leaves was substantially reduced or even stopped under moderate and severe drought stress. Leaf blade hydraulic resistance accounted for most of the total shoot resistance. However, hydraulic conductance of the whole root system (K root ) was not significantly reduced until water stress became very severe in pot-grown vines. Significant correlations between K plant , K canopy and Ψ s , K canopy and leaf gas exchange, K leaf and Ψ s , and K leaf and A support a link between water supply, leaf water status and gas exchange. Upon re-watering, Ψ s recovered faster than gas exchange and leaf-shoot hydraulics. A gradual recovery of hydraulic functionality of plant organs was also observed, the leaves being the last to recover after rewatering. In pot-grown vines, K canopy recovered rather

Feasibility of a Hydraulic Power Assist System for Use in Hybrid Neuroprostheses

PubMed Central

Foglyano, Kevin M.; Kobetic, Rudi; To, Curtis S.; Bulea, Thomas C.; Schnellenberger, John R.; Audu, Musa L.; Nandor, Mark J.; Quinn, Roger D.; Triolo, Ronald J.

2015-01-01

Feasibility of using pressurized hydraulic fluid as a source of on-demand assistive power for hybrid neuroprosthesis combining exoskeleton with functional neuromuscular stimulation was explored. Hydraulic systems were selected as an alternative to electric motors for their high torque/mass ratio and ability to be located proximally on the exoskeleton and distribute power distally to assist in moving the joints. The power assist system (PAS) was designed and constructed using off-the-shelf components to test the feasibility of using high pressure fluid from an accumulator to provide assistive torque to an exoskeletal hip joint. The PAS was able to provide 21 Nm of assistive torque at an input pressure of 3171 kPa with a response time of 93 ms resulting in 32° of hip flexion in an able-bodied test. The torque output was independent of initial position of the joint and was linearly related to pressure. Thus, accumulator pressure can be specified to provide assistive torque as needed in exoskeletal devices for walking or stair climbing beyond those possible either volitionally or with electrical stimulation alone. PMID:27017963

Measurement of hydraulic characteristics of porous media used to grow plants in microgravity

NASA Technical Reports Server (NTRS)

Steinberg, Susan L.; Poritz, Darwin

2005-01-01

Understanding the effect of gravity on hydraulic properties of plant growth medium is essential for growing plants in space. The suitability of existing models to simulate hydraulic properties of porous medium is uncertain due to limited understanding of fundamental mechanisms controlling water and air transport in microgravity. The objective of this research was to characterize saturated and unsaturated hydraulic conductivity (K) of two particle-size distributions of baked ceramic aggregate using direct measurement techniques compatible with microgravity. Steady state (Method A) and instantaneous profile measurement (Method B) methods for K were used in a single experimental unit with horizontal flow through thin sections of porous medium providing an earth-based analog to microgravity. Comparison between methods was conducted using a crossover experimental design compatible with limited resources of space flight. Satiated (natural saturation) K ranged from 0.09 to 0.12 cm s-1 and 0.5 to >1 cm s-1 for 0.25- to 1- and 1- to 2-mm media, respectively. The K at the interaggregate/intraaggregate transition was approximately 10(-4) cm s-1 for both particle-size distributions. Significant differences in log(10)K due to method and porous medium were less than one order of magnitude and were attributed to variability in air entrapment. The van Genuchten/Mualem parametric models provided an adequate prediction of K of the interaggregate pore space, using residual water content for that pore space. The instantaneous profile method covers the range of water contents relevant to plant growth using fewer resources than Method A, all advantages for space flight where mass, volume, and astronaut time are limited.

Amistad Power Plant.

DTIC Science & Technology

1983-10-01

Worh District AMISTAD POWEI PLANT DEL RIO, TEXAS DTICS LECTE DEC 2 11983 OCTOBER 1063 88 11 281 DISTRIBUTION STATEMENT A Approved fca public relea...A I I I 1 1 ... CORPS OF ENGINEERS FORT WORTH DISTRICT, TEXAS FINAL FOUNDATION REPORT AMISTAD POWER PLANT NTIS G- xi DTI’. T" Jus! if - Distr ’. Avai...Wayne E. McIntosh. Colonel Donald Palladino and Colonel Theodore Stroup served as District Engineers during construction of the Amistad Power Plant

Hydraulics of Asteroxylon mackei, an early Devonian vascular plant, and the early evolution of water transport tissue in terrestrial plants.

PubMed

Wilson, J P; Fischer, W W

2011-03-01

The core of plant physiology is a set of functional solutions to a tradeoff between CO(2) acquisition and water loss. To provide an important evolutionary perspective on how the earliest land plants met this tradeoff, we constructed a mathematical model (constrained geometrically with measurements of fossils) of the hydraulic resistance of Asteroxylon, an Early Devonian plant. The model results illuminate the water transport physiology of one of the earliest vascular plants. Results show that Asteroxylon's vascular system contains cells with low hydraulic resistances; these resistances are low because cells were covered by scalariform pits, elliptical structures that permit individual cells to have large areas for water to pass from one cell to another. Asteroxylon could move a large amount of water quickly given its large pit areas; however, this would have left these plants particularly vulnerable to damage from excessive evapotranspiration. These results highlight a repeated pattern in plant evolution, wherein the evolution of highly conductive vascular tissue precedes the appearance of adaptations to increase water transport safety. Quantitative insight into the vascular transport of Asteroxylon also allows us to reflect on the quality of CO(2) proxy estimates based on early land plant fossils. Because Asteroxylon's vascular tissue lacked any safety features to prevent permanent damage, it probably used stomatal abundance and behavior to prevent desiccation. If correct, low stomatal frequencies in Asteroxylon reflect the need to limit evapotranspiration, rather than adaptation to high CO(2) concentrations in the atmosphere. More broadly, methods to reveal and understand water transport in extinct plants have a clear use in testing and bolstering fossil plant-based paleoclimate proxies. © 2011 Blackwell Publishing Ltd.

Penstock leakage at the Robert Moses Niagara Power Plant - Investigation, design, and construction

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

Dumont, M.F.; Baker, C.H.; Broderick, W.

1995-12-31

This paper describes an investigation of observed penstock leakage and related gallery flooding at the Robert Moses Niagara Power Plant, in Lewiston, New York; engineering design of alternative remediation measures; test grouting of a dewatered penstock in 1991; and the subsequent grouting of the remaining twelve penstocks. The Robert Moses Niagara Power Plant is the lower part of the Niagara Pumped Storage Project, which is owned and operated by the New York Power Authority. Water diverted some 4 miles (6.4 km) upstream of the plant is passed through 13 individual penstocks 28 ft (8.5 m) in diameter to a powermore » plant on the right bank of the Niagara River. The net head at the plant is 300 ft (91.4 m), and the hydraulic capacity is about 91,000 cfs (2,575 m{sup 3}/s). The total installed capacity is about 2,000 MW. Since completion of construction in 1962 there had been recurring problems with flooding of the floors at the upper intake galleries. This was particularly noticeable during periods of heavy rainfall when the existing storm drains were close to their design capacity. The paper presents details of the investigations, including penstock inspection, methods of flow measurement and analysis, design criteria for the grout selected, details of the drilling and grout placement, and the anticipated long-term performance of the grout in service.« less

The blind men and the elephant: the impact of context and scale in evaluating conflicts between plant hydraulic safety and efficiency

Treesearch

Frederick C. Meinzer; Katherine A. McCulloh; Barbara Lachenbruch; David R. Woodruff; Daniel M. Johnson

2010-01-01

Given the fundamental importance of xylem safety and efficiency for plant survival and fitness, it is not surprising that these are among the most commonly studied features of hydraulic architecture. However, much remains to be learned about the nature and universality of conflicts between hydraulic safety and efficiency. Although selection for suites of hydraulic...

Topographic variations of water supply and plant hydraulics in a mountainous forest

NASA Astrophysics Data System (ADS)

Tai, X.; Mackay, D. S.; Ewers, B. E.; Parsekian, A.; Sperry, J.; Beverly, D.; Speckman, H. N.; Ohara, N.; Fantello, N.; Kelleners, T.; Fullhart, A. T.

2017-12-01

How plants respond to variable local water supply in complex soil-topography systems is not clear although critical. This has been attributed to a lack of integrated models that can resolve relevant hydrological and physiological mechanisms and intensive field monitoring to inform/evaluate such a model. This research addresses these knowledge gaps by leveraging a newly developed distributed plant hydraulics model, ParFlow-TREES, and detailed geophysical and physiological measurements. Observations of sap flow, leaf water potentials, micrometeorology, and electrical resistivity tomography (ERT) are combined with the model to examine the key mechanisms affecting the spatial distribution of soil water and tree water stress. Modeling results showed higher soil water condition at bottom of the hillslope on average, corroborating the ERT-derived soil moisture observations. Hydraulic traits are critical to capture the sap flux dynamics of species with contrasting leaf water potential regulation strategies and heterogeneous soil drying at different hillslope positions. These results suggested the integrated effect of topography and plants on the evolvement of soil moisture distribution. Furthermore, sensitivity analysis demonstrated the importance of using distributed observations to validate/calibrate distributed models. Focusing on lumped variables or only one particular variable might give misleading conclusions. Co-located observations improve the characterization of plant traits and local living environment, providing key information needed as a first step in resolving the form and function of the critical zone from bedrock to atmosphere. We will discuss the broader implications and potential applications of this intensive data-model comparison at other sites and greater spatial extent.

Raising the Bar: Increased Hydraulic Pressure Allows Unprecedented High Power Densities in Pressure-Retarded Osmosis

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

Straub, AP; Yip, NY; Elimelech, M

2014-01-01

Pressure-retarded osmosis (PRO) has the potential to generate sustainable energy from salinity gradients. PRO is typically considered for operation with river water and seawater, but a far greater energy of mixing can be harnessed from hypersaline solutions. This study investigates the power density that can be obtained in PRO from such concentrated solutions. Thin-film composite membranes with an embedded woven mesh were supported by tricot fabric feed spacers in a specially designed crossflow cell to maximize the operating pressure of the system, reaching a stable applied hydraulic pressure of 48 bar (700 psi) for more than 10 h. Operation atmore » this increased hydraulic pressure allowed unprecedented power densities, up to 60 W/m(2) with a 3 M (180 g/L) NaCl draw solution. Experimental power densities demonstrate reasonable agreement with power densities modeled using measured membrane properties, indicating high-pressure operation does not drastically alter membrane performance. Our findings exhibit the promise of the generation of power from high-pressure PRO with concentrated solutions.« less

Circadian patterns of xylem sap properties and their covariation with plant hydraulic traits in hybrid aspen.

PubMed

Meitern, Annika; Õunapuu-Pikas, Eele; Sellin, Arne

2017-06-01

Physiological processes taking place in plants are subject to diverse circadian patterns but some of them are poorly documented in natural conditions. The daily dynamics of physico-chemical properties of xylem sap and their covariation with tree hydraulic traits were investigated in hybrid aspen (Populus tremula L.×P. tremuloides Michx) in field conditions in order to clarify which environmental drivers govern the daily variation in these parameters. K + concentration ([K + ]), electrical conductivity (σ sap ), osmolality (Osm) and pH of the xylem sap, as well as branch hydraulic traits, were measured in the field over 24-h cycles. All studied xylem sap properties and hydraulic characteristics including whole-branch (K wb ), leaf blade (K lb ) and petiole hydraulic conductances (K P ) showed clear daily dynamics. Air temperature (T A ) and photosynthetic photon flux density (PPFD), but also water vapour pressure deficit (VPD) and relative humidity (RH), had significant impacts on K wb K lb , K P , [K + ] and σ sap . Osm varied only with light intensity, while K B varied depending on atmospheric evaporative demand expressed as T A , VPD or RH. Xylem sap pH depended inversely on soil water potential (Ψ S ) and during daylight also on VPD. Although soil water content was close to saturation during the study period, Ψ S influenced also [K + ] and σ sap . The present study presents evidence of coupling between circadian patterns of xylem sap properties and plant hydraulic conductance providing adequate water supply to foliage under environmental conditions characterised by diurnal variation. Copyright © 2017 Elsevier GmbH. All rights reserved.

Coupled Monte Carlo neutronics and thermal hydraulics for power reactors

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

Bernnat, W.; Buck, M.; Mattes, M.

The availability of high performance computing resources enables more and more the use of detailed Monte Carlo models even for full core power reactors. The detailed structure of the core can be described by lattices, modeled by so-called repeated structures e.g. in Monte Carlo codes such as MCNP5 or MCNPX. For cores with mainly uniform material compositions, fuel and moderator temperatures, there is no problem in constructing core models. However, when the material composition and the temperatures vary strongly a huge number of different material cells must be described which complicate the input and in many cases exceed code ormore » memory limits. The second problem arises with the preparation of corresponding temperature dependent cross sections and thermal scattering laws. Only if these problems can be solved, a realistic coupling of Monte Carlo neutronics with an appropriate thermal-hydraulics model is possible. In this paper a method for the treatment of detailed material and temperature distributions in MCNP5 is described based on user-specified internal functions which assign distinct elements of the core cells to material specifications (e.g. water density) and temperatures from a thermal-hydraulics code. The core grid itself can be described with a uniform material specification. The temperature dependency of cross sections and thermal neutron scattering laws is taken into account by interpolation, requiring only a limited number of data sets generated for different temperatures. Applications will be shown for the stationary part of the Purdue PWR benchmark using ATHLET for thermal- hydraulics and for a generic Modular High Temperature reactor using THERMIX for thermal- hydraulics. (authors)« less

Prolonged experimental drought reduces plant hydraulic conductance and transpiration and increases mortality in a piñon-juniper woodland.

PubMed

Pangle, Robert E; Limousin, Jean-Marc; Plaut, Jennifer A; Yepez, Enrico A; Hudson, Patrick J; Boutz, Amanda L; Gehres, Nathan; Pockman, William T; McDowell, Nate G

2015-04-01

Plant hydraulic conductance (k s) is a critical control on whole-plant water use and carbon uptake and, during drought, influences whether plants survive or die. To assess long-term physiological and hydraulic responses of mature trees to water availability, we manipulated ecosystem-scale water availability from 2007 to 2013 in a piñon pine (Pinus edulis) and juniper (Juniperus monosperma) woodland. We examined the relationship between k s and subsequent mortality using more than 5 years of physiological observations, and the subsequent impact of reduced hydraulic function and mortality on total woody canopy transpiration (E C) and conductance (G C). For both species, we observed significant reductions in plant transpiration (E) and k s under experimentally imposed drought. Conversely, supplemental water additions increased E and k s in both species. Interestingly, both species exhibited similar declines in k s under the imposed drought conditions, despite their differing stomatal responses and mortality patterns during drought. Reduced whole-plant k s also reduced carbon assimilation in both species, as leaf-level stomatal conductance (g s) and net photosynthesis (A n) declined strongly with decreasing k s. Finally, we observed that chronically low whole-plant k s was associated with greater canopy dieback and mortality for both piñon and juniper and that subsequent reductions in woody canopy biomass due to mortality had a significant impact on both daily and annual canopy E C and G C. Our data indicate that significant reductions in k s precede drought-related tree mortality events in this system, and the consequence is a significant reduction in canopy gas exchange and carbon fixation. Our results suggest that reductions in productivity and woody plant cover in piñon-juniper woodlands can be expected due to reduced plant hydraulic conductance and increased mortality of both piñon pine and juniper under anticipated future conditions of more frequent and

Prolonged experimental drought reduces plant hydraulic conductance and transpiration and increases mortality in a piñon–juniper woodland

DOE PAGES

Pangle, Robert E.; Limousin, Jean -Marc; Plaut, Jennifer A.; ...

2015-03-23

Plant hydraulic conductance (k s) is a critical control on whole-plant water use and carbon uptake and, during drought, influences whether plants survive or die. To assess long-term physiological and hydraulic responses of mature trees to water availability, we manipulated ecosystem-scale water availability from 2007 to 2013 in a piñon pine ( Pinus edulis) and juniper ( Juniperus monosperma) woodland. We examined the relationship between k s and subsequent mortality using more than 5 years of physiological observations, and the subsequent impact of reduced hydraulic function and mortality on total woody canopy transpiration (E C) and conductance (G C). Formore » both species, we observed significant reductions in plant transpiration (E) and k s under experimentally imposed drought. Conversely, supplemental water additions increased E and k s in both species. Interestingly, both species exhibited similar declines in k s under the imposed drought conditions, despite their differing stomatal responses and mortality patterns during drought. Reduced whole-plant k s also reduced carbon assimilation in both species, as leaf-level stomatal conductance (g s) and net photosynthesis (A n) declined strongly with decreasing k s. Finally, we observed that chronically low whole-plant k s was associated with greater canopy dieback and mortality for both piñon and juniper and that subsequent reductions in woody canopy biomass due to mortality had a significant impact on both daily and annual canopy E C and G C. Our data indicate that significant reductions in k s precede drought-related tree mortality events in this system, and the consequence is a significant reduction in canopy gas exchange and carbon fixation. Our results suggest that reductions in productivity and woody plant cover in piñon–juniper woodlands can be expected due to reduced plant hydraulic conductance and increased mortality of both piñon pine and juniper under anticipated future conditions of more

Prolonged experimental drought reduces plant hydraulic conductance and transpiration and increases mortality in a piñon–juniper woodland

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

Pangle, Robert E.; Limousin, Jean -Marc; Plaut, Jennifer A.

Plant hydraulic conductance (k s) is a critical control on whole-plant water use and carbon uptake and, during drought, influences whether plants survive or die. To assess long-term physiological and hydraulic responses of mature trees to water availability, we manipulated ecosystem-scale water availability from 2007 to 2013 in a piñon pine ( Pinus edulis) and juniper ( Juniperus monosperma) woodland. We examined the relationship between k s and subsequent mortality using more than 5 years of physiological observations, and the subsequent impact of reduced hydraulic function and mortality on total woody canopy transpiration (E C) and conductance (G C). Formore » both species, we observed significant reductions in plant transpiration (E) and k s under experimentally imposed drought. Conversely, supplemental water additions increased E and k s in both species. Interestingly, both species exhibited similar declines in k s under the imposed drought conditions, despite their differing stomatal responses and mortality patterns during drought. Reduced whole-plant k s also reduced carbon assimilation in both species, as leaf-level stomatal conductance (g s) and net photosynthesis (A n) declined strongly with decreasing k s. Finally, we observed that chronically low whole-plant k s was associated with greater canopy dieback and mortality for both piñon and juniper and that subsequent reductions in woody canopy biomass due to mortality had a significant impact on both daily and annual canopy E C and G C. Our data indicate that significant reductions in k s precede drought-related tree mortality events in this system, and the consequence is a significant reduction in canopy gas exchange and carbon fixation. Our results suggest that reductions in productivity and woody plant cover in piñon–juniper woodlands can be expected due to reduced plant hydraulic conductance and increased mortality of both piñon pine and juniper under anticipated future conditions of more

Design of an Adaptive Power Regulation Mechanism and a Nozzle for a Hydroelectric Power Plant Turbine Test Rig

NASA Astrophysics Data System (ADS)

Mert, Burak; Aytac, Zeynep; Tascioglu, Yigit; Celebioglu, Kutay; Aradag, Selin; ETU Hydro Research Center Team

2014-11-01

This study deals with the design of a power regulation mechanism for a Hydroelectric Power Plant (HEPP) model turbine test system which is designed to test Francis type hydroturbines up to 2 MW power with varying head and flow(discharge) values. Unlike the tailor made regulation mechanisms of full-sized, functional HEPPs; the design for the test system must be easily adapted to various turbines that are to be tested. In order to achieve this adaptability, a dynamic simulation model is constructed in MATLAB/Simulink SimMechanics. This model acquires geometric data and hydraulic loading data of the regulation system from Autodesk Inventor CAD models and Computational Fluid Dynamics (CFD) analysis respectively. The dynamic model is explained and case studies of two different HEPPs are performed for validation. CFD aided design of the turbine guide vanes, which is used as input for the dynamic model, is also presented. This research is financially supported by Turkish Ministry of Development.

Use of microalgae to remove pollutants from power plant discharges

DOEpatents

Wilde, Edward W.; Benemann, John R.; Weissman, Joseph C.; Tillett, David M.

1991-01-01

A method and system for removing pollutants dissolved in the aqueous discharge of a plant, such as a power plant, from a body of water having known hydraulogy and physicochemical characteristics, the method comprising (a) modifying the hydraulic system of the body of water including use of physical barriers to define a zone in a portion of the body of water which zone includes the discharge point and where the water has a range of physicochemical characteristics; (b) selecting a large and preferably filamentous, planktonically growing strain of algae adapted to absorb the particular pollutants and genetically dominating algae at the physicochemical characteristics of the zone; (c) establishing a colony of the selected algal strain in the zone; (d) harvesting a portion of the colony; and (e) reinnoculating the zone near the discharge point with a fraction of the harvested portion. The fraction used for reinnoculation can be adjusted to balance the rate of pollutant removal to the rate of pollutant discharge.

Unraveling the Effects of Plant Hydraulics on Stomatal Closure during Water Stress in Walnut

PubMed Central

Cochard, Hervé; Coll, Lluis; Le Roux, Xavier; Améglio, Thierry

2002-01-01

The objectives of the study were to identify the relevant hydraulic parameters associated with stomatal regulation during water stress and to test the hypothesis of a stomatal control of xylem embolism in walnut (Juglans regia × nigra) trees. The hydraulic characteristics of the sap pathway were experimentally altered with different methods to alter plant transpiration (Eplant) and stomatal conductance (gs). Potted trees were exposed to a soil water depletion to alter soil water potential (Ψsoil), soil resistance (Rsoil), and root hydraulic resistances (Rroot). Soil temperature was changed to alter Rroot alone. Embolism was created in the trunk to increase shoot resistance (Rshoot). Stomata closed in response to these stresses with the effect of maintaining the water pressure in the leaf rachis xylem (Prachis) above −1.4 MPa and the leaf water potential (Ψleaf) above −1.6 MPa. The same dependence of Eplant and gs on Prachis or Ψleaf was always observed. This suggested that stomata were not responding to changes in Ψsoil, Rsoil, Rroot, or Rshoot per se but rather to their impact on Prachis and/or Ψleaf. Leaf rachis was the most vulnerable organ, with a threshold Prachis for embolism induction of −1.4 MPa. The minimum Ψleaf values corresponded to leaf turgor loss point. This suggested that stomata are responding to leaf water status as determined by transpiration rate and plant hydraulics and that Prachis might be the physiological parameter regulated by stomatal closure during water stress, which would have the effect of preventing extensive developments of cavitation during water stress. PMID:11788773

Do root hydraulic properties change during the early vegetative stage of plant development in barley (Hordeum vulgare)?

PubMed Central

Suku, Shimi; Knipfer, Thorsten; Fricke, Wieland

2014-01-01

Background and Aims As annual crops develop, transpirational water loss increases substantially. This increase has to be matched by an increase in water uptake through the root system. The aim of this study was to assess the contributions of changes in intrinsic root hydraulic conductivity (Lp, water uptake per unit root surface area, driving force and time), driving force and root surface area to developmental increases in root water uptake. Methods Hydroponically grown barley plants were analysed during four windows of their vegetative stage of development, when they were 9–13, 14–18, 19–23 and 24–28 d old. Hydraulic conductivity was determined for individual roots (Lp) and for entire root systems (Lpr). Osmotic Lp of individual seminal and adventitious roots and osmotic Lpr of the root system were determined in exudation experiments. Hydrostatic Lp of individual roots was determined by root pressure probe analyses, and hydrostatic Lpr of the root system was derived from analyses of transpiring plants. Key Results Although osmotic and hydrostatic Lp and Lpr values increased initially during development and were correlated positively with plant transpiration rate, their overall developmental increases (about 2-fold) were small compared with increases in transpirational water loss and root surface area (about 10- to 40-fold). The water potential gradient driving water uptake in transpiring plants more than doubled during development, and potentially contributed to the increases in plant water flow. Osmotic Lpr of entire root systems and hydrostatic Lpr of transpiring plants were similar, suggesting that the main radial transport path in roots was the cell-to-cell path at all developmental stages. Conclusions Increase in the surface area of root system, and not changes in intrinsic root hydraulic properties, is the main means through which barley plants grown hydroponically sustain an increase in transpirational water loss during their vegetative

Do root hydraulic properties change during the early vegetative stage of plant development in barley (Hordeum vulgare)?

PubMed

Suku, Shimi; Knipfer, Thorsten; Fricke, Wieland

2014-02-01

As annual crops develop, transpirational water loss increases substantially. This increase has to be matched by an increase in water uptake through the root system. The aim of this study was to assess the contributions of changes in intrinsic root hydraulic conductivity (Lp, water uptake per unit root surface area, driving force and time), driving force and root surface area to developmental increases in root water uptake. Hydroponically grown barley plants were analysed during four windows of their vegetative stage of development, when they were 9-13, 14-18, 19-23 and 24-28 d old. Hydraulic conductivity was determined for individual roots (Lp) and for entire root systems (Lp(r)). Osmotic Lp of individual seminal and adventitious roots and osmotic Lp(r) of the root system were determined in exudation experiments. Hydrostatic Lp of individual roots was determined by root pressure probe analyses, and hydrostatic Lp(r) of the root system was derived from analyses of transpiring plants. Although osmotic and hydrostatic Lp and Lp(r) values increased initially during development and were correlated positively with plant transpiration rate, their overall developmental increases (about 2-fold) were small compared with increases in transpirational water loss and root surface area (about 10- to 40-fold). The water potential gradient driving water uptake in transpiring plants more than doubled during development, and potentially contributed to the increases in plant water flow. Osmotic Lp(r) of entire root systems and hydrostatic Lp(r) of transpiring plants were similar, suggesting that the main radial transport path in roots was the cell-to-cell path at all developmental stages. Increase in the surface area of root system, and not changes in intrinsic root hydraulic properties, is the main means through which barley plants grown hydroponically sustain an increase in transpirational water loss during their vegetative development.

Coordination of stem and leaf hydraulic conductance in southern California shrubs: a test of the hydraulic segmentation hypothesis.

PubMed

Pivovaroff, Alexandria L; Sack, Lawren; Santiago, Louis S

2014-08-01

Coordination of water movement among plant organs is important for understanding plant water use strategies. The hydraulic segmentation hypothesis (HSH) proposes that hydraulic conductance in shorter lived, 'expendable' organs such as leaves and longer lived, more 'expensive' organs such as stems may be decoupled, with resistance in leaves acting as a bottleneck or 'safety valve'. We tested the HSH in woody species from a Mediterranean-type ecosystem by measuring leaf hydraulic conductance (Kleaf) and stem hydraulic conductivity (KS). We also investigated whether leaves function as safety valves by relating Kleaf and the hydraulic safety margin (stem water potential minus the water potential at which 50% of conductivity is lost (Ψstem-Ψ50)). We also examined related plant traits including the operating range of water potentials, wood density, leaf mass per area, and leaf area to sapwood area ratio to provide insight into whole-plant water use strategies. For hydrated shoots, Kleaf was negatively correlated with KS , supporting the HSH. Additionally, Kleaf was positively correlated with the hydraulic safety margin and negatively correlated with the leaf area to sapwood area ratio. Consistent with the HSH, our data indicate that leaves may act as control valves for species with high KS , or a low safety margin. This critical role of leaves appears to contribute importantly to plant ecological specialization in a drought-prone environment. © 2014 The Authors. New Phytologist © 2014 New Phytologist Trust.

Thermal-hydraulic analysis capabilities and methods development at NYPA

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

Feltus, M.A.

1987-01-01

The operation of a nuclear power plant must be regularly supported by various thermal-hydraulic (T/H) analyses that may include final safety analysis report (FSAR) design basis calculations and licensing evaluations and conservative and best-estimate analyses. The development of in-house T/H capabilities provides the following advantages: (a) it leads to a better understanding of the plant design basis and operating characteristics; (b) methods developed can be used to optimize plant operations and enhance plant safety; (c) such a capability can be used for design reviews, checking vendor calculations, and evaluating proposed plant modifications; and (d) in-house capability reduces the cost ofmore » analysis. This paper gives an overview of the T/H capabilities and current methods development activity within the engineering department of the New York Power Authority (NYPA) and will focus specifically on reactor coolant system (RCS) transients and plant dynamic response for non-loss-of-coolant accident events. This paper describes NYPA experience in performing T/H analyses in support of pressurized water reactor plant operation.« less

Root morphology, hydraulic conductivity and plant water relations of high-yielding rice grown under aerobic conditions.

PubMed

Kato, Yoichiro; Okami, Midori

2011-09-01

Increasing physical water scarcity is a major constraint for irrigated rice (Oryza sativa) production. 'Aerobic rice culture' aims to maximize yield per unit water input by growing plants in aerobic soil without flooding or puddling. The objective was to determine (a) the effect of water management on root morphology and hydraulic conductance, and (b) their roles in plant-water relationships and stomatal conductance in aerobic culture. Root system development, stomatal conductance (g(s)) and leaf water potential (Ψ(leaf)) were monitored in a high-yielding rice cultivar ('Takanari') under flooded and aerobic conditions at two soil moisture levels [nearly saturated (> -10 kPa) and mildly dry (> -30 kPa)] over 2 years. In an ancillary pot experiment, whole-plant hydraulic conductivity (soil-leaf hydraulic conductance; K(pa)) was measured under flooded and aerobic conditions. Adventitious root emergence and lateral root proliferation were restricted even under nearly saturated conditions, resulting in a 72-85 % reduction in total root length under aerobic culture conditions. Because of their reduced rooting size, plants grown under aerobic conditions tended to have lower K(pa) than plants grown under flooded conditions. Ψ(leaf) was always significantly lower in aerobic culture than in flooded culture, while g(s) was unchanged when the soil moisture was at around field capacity. g(s) was inevitably reduced when the soil water potential at 20-cm depth reached -20 kPa. Unstable performance of rice in water-saving cultivations is often associated with reduction in Ψ(leaf). Ψ(leaf) may reduce even if K(pa) is not significantly changed, but the lower Ψ(leaf) would certainly occur in case K(pa) reduces as a result of lower water-uptake capacity under aerobic conditions. Rice performance in aerobic culture might be improved through genetic manipulation that promotes lateral root branching and rhizogenesis as well as deep rooting.

Improvement of automatic control systems of high-power turbines of PAO tubroatom for nuclear power plants

NASA Astrophysics Data System (ADS)

Shvetsov, V. L.; Babaev, I. N.

2017-09-01

The main technical solutions applied by PAO Turboatom used as the compensatory measures at the increase of the period of nonstop operation of nuclear power plants' (NPP) turbines with VVER-1000 type reactors up to 18 months are (1) replacing the standard hydraulic speed controller with an electronic one, (2) introduction of overclocking protection, (3) modernization of units of stop-control valves of high pressures, (4) installation of locking dampers on the receiver tubes of turbines of the first and second modification, and (5) improving the quality of repairs by reviewing the requirements for their implementation. The introduction of complex diagnostics of a control system on the basis of automatic treatment of results of registration of working parameters of the turbine is allocated as a separate prospective direction. Using an electronic controller of speed makes it possible to simplify the procedure of its inclusion in work at the failure of an electro-hydraulic system of control and vice versa. The regimes of maintaining the turbine rotor speed, steam pressure on the outlet of turbine, and the positions of main servomotors were introduced into the functions of the electronic controller. An electronic controller of speed includes its own electro-hydraulic transducer, turbine rotor speed sensor, and sensors of the position of main servomotors. Into the functions of electro- hydraulic control system and electronic speed controller, the function of overclocking protection, which determines the formation of commands for stopping the turbine at the exceeding of both the defined level of rotation speed and the defined combination of achieved rotation speed and angular acceleration of rotor, was introduced. To simplify the correction of forces acting on the control valve cups, the design of the cups was changed, and it has the profiled inserts. The solutions proposed were implemented on K-1100-60/1500-2M turbines of Rostov NPP. From the composition of control system

Fluid dynamics of acoustic and hydrodynamic cavitation in hydraulic power systems.

PubMed

Ferrari, A

2017-03-01

Cavitation is the transition from a liquid to a vapour phase, due to a drop in pressure to the level of the vapour tension of the fluid. Two kinds of cavitation have been reviewed here: acoustic cavitation and hydrodynamic cavitation. As acoustic cavitation in engineering systems is related to the propagation of waves through a region subjected to liquid vaporization, the available expressions of the sound speed are discussed. One of the main effects of hydrodynamic cavitation in the nozzles and orifices of hydraulic power systems is a reduction in flow permeability. Different discharge coefficient formulae are analysed in this paper: the Reynolds number and the cavitation number result to be the key fluid dynamical parameters for liquid and cavitating flows, respectively. The latest advances in the characterization of different cavitation regimes in a nozzle, as the cavitation number reduces, are presented. The physical cause of choked flows is explained, and an analogy between cavitation and supersonic aerodynamic flows is proposed. The main approaches to cavitation modelling in hydraulic power systems are also reviewed: these are divided into homogeneous-mixture and two-phase models. The homogeneous-mixture models are further subdivided into barotropic and baroclinic models. The advantages and disadvantages of an implementation of the complete Rayleigh-Plesset equation are examined.

Fluid dynamics of acoustic and hydrodynamic cavitation in hydraulic power systems

NASA Astrophysics Data System (ADS)

Ferrari, A.

2017-03-01

Cavitation is the transition from a liquid to a vapour phase, due to a drop in pressure to the level of the vapour tension of the fluid. Two kinds of cavitation have been reviewed here: acoustic cavitation and hydrodynamic cavitation. As acoustic cavitation in engineering systems is related to the propagation of waves through a region subjected to liquid vaporization, the available expressions of the sound speed are discussed. One of the main effects of hydrodynamic cavitation in the nozzles and orifices of hydraulic power systems is a reduction in flow permeability. Different discharge coefficient formulae are analysed in this paper: the Reynolds number and the cavitation number result to be the key fluid dynamical parameters for liquid and cavitating flows, respectively. The latest advances in the characterization of different cavitation regimes in a nozzle, as the cavitation number reduces, are presented. The physical cause of choked flows is explained, and an analogy between cavitation and supersonic aerodynamic flows is proposed. The main approaches to cavitation modelling in hydraulic power systems are also reviewed: these are divided into homogeneous-mixture and two-phase models. The homogeneous-mixture models are further subdivided into barotropic and baroclinic models. The advantages and disadvantages of an implementation of the complete Rayleigh-Plesset equation are examined.

Fluid dynamics of acoustic and hydrodynamic cavitation in hydraulic power systems

PubMed Central

2017-01-01

Cavitation is the transition from a liquid to a vapour phase, due to a drop in pressure to the level of the vapour tension of the fluid. Two kinds of cavitation have been reviewed here: acoustic cavitation and hydrodynamic cavitation. As acoustic cavitation in engineering systems is related to the propagation of waves through a region subjected to liquid vaporization, the available expressions of the sound speed are discussed. One of the main effects of hydrodynamic cavitation in the nozzles and orifices of hydraulic power systems is a reduction in flow permeability. Different discharge coefficient formulae are analysed in this paper: the Reynolds number and the cavitation number result to be the key fluid dynamical parameters for liquid and cavitating flows, respectively. The latest advances in the characterization of different cavitation regimes in a nozzle, as the cavitation number reduces, are presented. The physical cause of choked flows is explained, and an analogy between cavitation and supersonic aerodynamic flows is proposed. The main approaches to cavitation modelling in hydraulic power systems are also reviewed: these are divided into homogeneous-mixture and two-phase models. The homogeneous-mixture models are further subdivided into barotropic and baroclinic models. The advantages and disadvantages of an implementation of the complete Rayleigh–Plesset equation are examined. PMID:28413332

Design of An Energy Efficient Hydraulic Regenerative circuit

NASA Astrophysics Data System (ADS)

Ramesh, S.; Ashok, S. Denis; Nagaraj, Shanmukha; Adithyakumar, C. R.; Reddy, M. Lohith Kumar; Naulakha, Niranjan Kumar

2018-02-01

Increasing cost and power demand, leads to evaluation of new method to increase through productivity and help to solve the power demands. Many researchers have break through to increase the efficiency of a hydraulic power pack, one of the promising methods is the concept of regenerative. The objective of this research work is to increase the efficiency of a hydraulic circuit by introducing a concept of regenerative circuit. A Regenerative circuit is a system that is used to speed up the extension stroke of the double acting single rod hydraulic cylinder. The output is connected to the input in the directional control value. By this concept, increase in velocity of the piston and decrease the cycle time. For the research, a basic hydraulic circuit and a regenerative circuit are designated and compared both with their results. The analysis was based on their time taken for extension and retraction of the piston. From the detailed analysis of both the hydraulic circuits, it is found that the efficiency by introducing hydraulic regenerative circuit increased by is 5.3%. The obtained results conclude that, implementing hydraulic regenerative circuit in a hydraulic power pack decreases power consumption, reduces cycle time and increases productivity in a longer run.

76 FR 1469 - Calvert Cliffs Nuclear Power Plant, LLC; Calvert Cliffs Nuclear Power Plant, Unit Nos. 1 and 2...

Federal Register 2010, 2011, 2012, 2013, 2014

2011-01-10

... Impact Statement for License Renewal of Nuclear Plants, Calvert Cliffs Nuclear Power Plant (NUREG-1437... Nuclear Power Plant, LLC; Calvert Cliffs Nuclear Power Plant, Unit Nos. 1 and 2 Environmental Assessment... Plant, LLC, the licensee, for operation of the Calvert Cliffs Nuclear Power Plant, Unit Nos. 1 and 2...

Study of hydraulic power recovery from New Mexico water distribution systems

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

Schoenmackers, R.

1984-02-01

The results of a survey of New Mexico water distribution systems suitable for hydroelectric power development are reported. The objectives of the survey were to determine the potential for hydraulic power recovery from existing and planned water systems, to identify potential sites, and to study and recommend promising sites for further development. The survey found eleven sites in New Mexico water distribution systems with a total hydroelectric power potential of 736 kilowatts. Seven of these sites, or 439 kilowatts, could be developed immediately, having everything necessary in place but the turbine generator. These sites are located in the Bonito pipelinemore » near Carrizozo (2 sites), Raton, Ruidoso, Santa Fe, Sugarite, and Taos. If all seven sites were developed, the annual energy production could reach 3,800,000 kilowatt hours.« less

Current and anticipated uses of thermal-hydraulic codes in Germany

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

Teschendorff, V.; Sommer, F.; Depisch, F.

1997-07-01

In Germany, one third of the electrical power is generated by nuclear plants. ATHLET and S-RELAP5 are successfully applied for safety analyses of the existing PWR and BWR reactors and possible future reactors, e.g. EPR. Continuous development and assessment of thermal-hydraulic codes are necessary in order to meet present and future needs of licensing organizations, utilities, and vendors. Desired improvements include thermal-hydraulic models, multi-dimensional simulation, computational speed, interfaces to coupled codes, and code architecture. Real-time capability will be essential for application in full-scope simulators. Comprehensive code validation and quantification of uncertainties are prerequisites for future best-estimate analyses.

Neutron Imaging Reveals Internal Plant Hydraulic Dynamics

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

Warren, Jeffrey; Bilheux, Hassina Z; Kang, Misun

2013-01-01

Many terrestrial ecosystem processes are constrained by water availability and transport within the soil. Knowledge of plant water fluxes is thus critical for assessing mechanistic processes linked to biogeochemical cycles, yet resolution of root structure and xylem water transport dynamics has been a particularly daunting task for the ecologist. Through neutron imaging, we demonstrate the ability to non-invasively monitor individual root functionality and water fluxes within Zea mays L. (maize) and Panicum virgatum L. (switchgrass) seedlings growing in a sandy medium. Root structure and growth were readily imaged by neutron radiography and neutron computed tomography. Seedlings were irrigated with watermore » or deuterium oxide and imaged through time as a growth lamp was cycled on to alter leaf demand for water. Sub-millimeter scale resolution reveals timing and magnitudes of root water uptake, redistribution within the roots, and root-shoot hydraulic linkages, relationships not well characterized by other techniques.« less

Proceedings of the American Power Conference. Volume 58-II

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

McBride, A.E.

1996-11-01

This book is part 2 of the proceedings of the American Power Conference, Technology for Competition and Globalization, 1996. The topics of the papers include structural plant design; challenges of the global marketplace; thermal hydraulic methods for nuclear power plant safety and operation; decontamination and decommissioning; competitive operations and maintenance; fuel opportunities; cooling; competitive power pricing; operations; transformers; relays; plant controls; training to meet the competitive future; burning technologies; ash and byproducts utilization; advanced systems; computer tools for plant design; globalization of power; power system protection and power quality; life extension; grounding; and transmission line equipment.

Arbuscular Mycorrhiza Improves Substrate Hydraulic Conductivity in the Plant Available Moisture Range Under Root Growth Exclusion.

PubMed

Bitterlich, Michael; Franken, Philipp; Graefe, Jan

2018-01-01

Arbuscular mycorrhizal fungi (AMF) proliferate in soils and are known to affect soil structure. Although their contribution to structure is extensively investigated, the consequences of those processes for soil water extractability and transport has, so far, gained surprisingly little attention. Therefore we asked, whether AMF can affect water retention and unsaturated hydraulic conductivity under exclusion of root ingrowth, in order to minimize plant driven effects. We carried out experiments with tomato inoculated with Rhizoglomus irregulare in a soil substrate with sand and vermiculite that created variation in colonization by mixed pots with wild type (WT) plants and mycorrhiza resistant (RMC) mutants. Sampling cores were introduced and used to assess substrate moisture retention dynamics and modeling of substrate water retention and hydraulic conductivity. AMF reduced the saturated water content and total porosity, but maintained air filled porosity in soil spheres that excluded root ingrowth. The water content between field capacity and the permanent wilting point (6-1500 kPa) was only reduced in mycorrhizal substrates that contained at least one RMC mutant. Plant available water contents correlated positively with soil protein contents. Soil protein contents were highest in pots that possessed the strongest hyphal colonization, but not significantly affected. Substrate conductivity increased up to 50% in colonized substrates in the physiologically important water potential range between 6 and 10 kPa. The improvements in hydraulic conductivity are restricted to substrates where at least one WT plant was available for the fungus, indicating a necessity of a functional symbiosis for this effect. We conclude that functional mycorrhiza alleviates the resistance to water movement through the substrate in substrate areas outside of the root zone.

The relationships between leaf economics and hydraulic traits of woody plants depend on water availability.

PubMed

Yin, Qiulong; Wang, Lei; Lei, Maolin; Dang, Han; Quan, Jiaxin; Tian, Tingting; Chai, Yongfu; Yue, Ming

2018-04-15

Leaf economics and hydraulic traits are simultaneously involved in the process of trading water for CO 2 , but the relationships between these two suites of traits remain ambiguous. Recently, Li et al. (2015) reported that leaf economics and hydraulic traits were decoupled in five tropical-subtropical forests in China. We tested the hypothesis that the relationships between economics and hydraulic traits may depend on water availability. We analysed five leaf economics traits, four hydraulic traits and anatomical structures of 47 woody species on the Loess Plateau with poor water availability and compared those data with Li et al. (2015) obtained in tropical-subtropical regions with adequate water. The results showed that plants on the Loess Plateau tend to have higher leaf tissue density (TD), leaf nitrogen concentrations and venation density (VD) and lower stomatal guard cell length (SL) and maximum stomatal conductance to water vapour (g wmax ). VD showed positive correlations with leaf nitrogen concentrations, palisade tissue thickness (PT) and ratio of palisade tissue thickness to spongy tissue thickness (PT/ST). Principal component analysis (PCA) showed a result opposite from those of tropical-subtropical regions: leaf economics and hydraulic traits were coupled on the Loess Plateau. A stable correlation between these two suites of traits may be more cost-effective on the Loess Plateau, where water availability is poor. The correlation of leaf economics and hydraulic traits may be a type of adaptation mechanism in arid conditions. Copyright © 2017 Elsevier B.V. All rights reserved.

FOREWORD: 26th IAHR Symposium on Hydraulic Machinery and Systems

NASA Astrophysics Data System (ADS)

Wu, Yulin; Wang, Zhengwei; Liu, Shuhong; Yuan, Shouqi; Luo, Xingqi; Wang, Fujun

2012-11-01

The 26th IAHR Symposium on Hydraulic Machinery and Systems, will be held in Beijing, China, 19-23 August 2012. It is jointly organized by Tsinghua University, State Key Laboratory of Hydro Science and Hydraulic Engineering, China, Jiangsu University, Xi'an University of Technology, China Agricultural University, National Engineering Research Center of Hydropower Equipment and Dongfang Electric Machinery Co., Ltd. It is the second time that China hosts such a symposium. By the end of 2011, the China electrical power system had a total of 1 050 GW installed power, out of which 220 GW was in hydropower plants. The energy produced in hydropower facilities was 662.6 TWh from a total of 4,720 TWh electrical energy production in 2011. Moreover, in 2020, new hydropower capacities are going to be developed, with a total of 180 GW installed power and an estimated 708 TWh/year energy production. And in 2011, the installed power of pumped storage stations was about 25GW. In 2020, the data will be 70GW. At the same time, the number of pumps used in China is increasing rapidly. China produces about 29,000,000 pumps with more than 220 series per year. By the end of 2011, the Chinese pumping system has a total of 950 GW installed power. The energy consumed in pumping facilities was 530 TWh in 2011. The pump energy consumption accounted for about 12% of the national electrical energy production. Therefore, there is a large market in the field of hydraulic machinery including water turbines, pump turbines and a variety of pumps in China. There are also many research projects in this field. For example, we have conducted National Key Research Projects on 1000 MW hydraulic turbine, and on the pump turbines with high head, as well as on the large capacity pumps for water supply. Tsinghua University of Beijing is proud to host the 26th IAHR Symposium on Hydraulic Machinery and Systems. Tsinghua University was established in 1911, after the founding of the People's Republic of China. It

Different hydraulic traits of woody plants from tropical forests with contrasting soil water availability.

PubMed

Zhu, Shi-Dan; Chen, Ya-Jun; Fu, Pei-Li; Cao, Kun-Fang

2017-11-01

In southwestern China, tropical karst forests (KF) and non-karst rain forests (NKF) have different species composition and forest structure owing to contrasting soil water availability, but with a few species that occur in both forests. Plant hydraulic traits are important for understanding the species' distribution patterns in these two forest types, but related studies are rare. In this study, we investigated hydraulic conductivity, vulnerability to drought-induced cavitation and wood anatomy of 23 abundant and typical woody species from a KF and a neighboring NKF, as well as two Bauhinia liana species common to both forests. We found that the KF species tended to have higher sapwood density, smaller vessel diameter, lower specific hydraulic conductivity (ks) and leaf to sapwood area ratio, and were more resistant to cavitation than NKF species. Across the 23 species distinctly occurring in either KF or NKF, there was a significant tradeoff between hydraulic efficiency and safety, which might be an underlying mechanism for distributions of these species across the two forests. Interestingly, by possessing rather large and long vessels, the two Bauhinia liana species had extremely high ks but were also high resistance to cavitation (escaping hydraulic tradeoff). This might be partially due to their distinctly dimorphic vessels, but contribute to their wide occurrence in both forests. © The Author 2017. Published by Oxford University Press. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

Hydraulic resistance of submerged flexible vegetation

NASA Astrophysics Data System (ADS)

Stephan, Ursula; Gutknecht, Dieter

2002-12-01

The main research objective consisted in analysing the influence of roughness caused by aquatic vegetation (av), in particular submerged macrophytes, on the overall flow field. These plants are highly flexible and behave differently depending on the flow situation. They also react substantially to the flow field and thus, the roughness becomes variable and dynamic. Conventional flow formulas, such as the Manning or the Strickler formula, are one-dimensional and based on integral flow parameters. They are not suitable for quantifying the roughness of av, because the flow is complex and more dimensional due to the variable behaviour of the plants. Therefore, the present investigation concentrates on the definition of a characteristic hydraulic roughness parameter to quantify the resistance of av. Within this investigation laboratory experiments were carried out with three different types of av, chosen with respect to varying plant structures as well as stem lengths. Velocity measurements above these plants were conducted to determine the relationship between the hydraulic roughness and the deflected plant height. The deflected plant height is used as the geometric roughness parameter, whereas the equivalent sand roughness based on the universal logarithmic law modified by Nikuradse was used as hydraulic roughness parameter. The influence of relative submergence on the hydraulic roughness was also analysed. The analysis of the velocity measurements illustrates that equivalent sand roughness and zero plane displacement of the logarithmic law are correlated to the deflected plant height and are equally to this height.

Current evaluation of hydraulics to replace the cable force transmission system for body-powered upper-limb prostheses.

PubMed

LeBlanc, M

1990-01-01

Present body-powered upper-limb prostheses use a cable control system employing World War II aircraft technology to transmit force from the body to the prosthesis for operation. The cable and associated hardware are located outside the prosthesis. Because individuals with arm amputations want prostheses that are natural looking with a smooth, soft outer surface, a design and development project was undertaken to replace the cable system with hydraulics located inside the prosthesis. Three different hydraulic transmission systems were built for evaluation, and other possibilities were explored. Results indicate that a hydraulic force transmission system remains an unmet challenge as a practical replacement for the cable system. The author was unable to develop a hydraulic system that meets the necessary dynamic requirements and is acceptable in size and appearance.

Nuclear Power Plants. Revised.

ERIC Educational Resources Information Center

Lyerly, Ray L.; Mitchell, Walter, III

This publication is one of a series of information booklets for the general public published by the United States Atomic Energy Commission. Among the topics discussed are: Why Use Nuclear Power?; From Atoms to Electricity; Reactor Types; Typical Plant Design Features; The Cost of Nuclear Power; Plants in the United States; Developments in Foreign…

Current and anticipated uses of thermal hydraulic codes at the Japan Atomic Energy Research Institute

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

Akimoto, Hajime; Kukita; Ohnuki, Akira

1997-07-01

The Japan Atomic Energy Research Institute (JAERI) is conducting several research programs related to thermal-hydraulic and neutronic behavior of light water reactors (LWRs). These include LWR safety research projects, which are conducted in accordance with the Nuclear Safety Commission`s research plan, and reactor engineering projects for the development of innovative reactor designs or core/fuel designs. Thermal-hydraulic and neutronic codes are used for various purposes including experimental analysis, nuclear power plant (NPP) safety analysis, and design assessment.

2. VIEW OF POWER PLANT LOOKING SOUTHEAST. Potomac Power ...

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

2. VIEW OF POWER PLANT LOOKING SOUTHEAST. - Potomac Power Plant, On West Virginia Shore of Potomac River, about 1 mile upriver from confluence with Shenandoah River, Harpers Ferry, Jefferson County, WV

76 FR 39908 - Calvert Cliffs Nuclear Power Plant, LLC; Calvert Cliffs Nuclear Power Plant, Unit Nos. 1 and 2...

Federal Register 2010, 2011, 2012, 2013, 2014

2011-07-07

... Nuclear Power Plant, LLC; Calvert Cliffs Nuclear Power Plant, Unit Nos. 1 and 2; Calvert Cliffs.... DPR-53 and DPR-69, for the Calvert Cliffs Nuclear Power Plant, Unit Nos. 1 and 2 (CCNPP), respectively... (ISFSI), currently held by Calvert Cliffs Nuclear Power Plant, LLC as owner and licensed operator...

Concentrating Solar Power Projects - Redstone Solar Thermal Power Plant |

Science.gov Websites

Concentrating Solar Power | NREL Redstone Solar Thermal Power Plant Status Date: September 8 , 2016 Project Overview Project Name: Redstone Solar Thermal Power Plant Country: South Africa Location ): 100.0 MW Turbine Capacity (Net): 100.0 MW Cooling Method: Dry cooling Thermal Storage Storage Type: 2

76 FR 4391 - Calvert Cliffs Nuclear Power Plant, LLC, Calvert Cliffs Nuclear Power Plant, Unit Nos. 1 and 2...

Federal Register 2010, 2011, 2012, 2013, 2014

2011-01-25

... Nuclear Power Plant, LLC, Calvert Cliffs Nuclear Power Plant, Unit Nos. 1 and 2; Exemption 1.0 Background Calvert Cliffs Nuclear Power Plant, LLC, the licensee, is the holder of Facility Operating License Nos. DPR-53 and DPR-69 which authorizes operation of the Calvert Cliffs Nuclear Power Plant, Unit Nos. 1...

75 FR 66802 - Calvert Cliffs Nuclear Power Plant, LLC; Calvert Cliffs Nuclear Power Plant, Unit Nos. 1 and 2...

Federal Register 2010, 2011, 2012, 2013, 2014

2010-10-29

... Nuclear Power Plant, LLC; Calvert Cliffs Nuclear Power Plant, Unit Nos. 1 and 2; Notice of Withdrawal of...) has granted the request of Calvert Cliffs Nuclear Power Plant, LLC, the licensee, to withdraw its... for the Calvert Cliffs Nuclear Power Plant, Unit Nos. 1 and 2, located in Calvert County, MD. The...

Simulation of hybrid solar power plants

NASA Astrophysics Data System (ADS)

Dieckmann, Simon; Dersch, Jürgen

2017-06-01

Hybrid solar power plants have the potential to combine advantages of two different technologies at the cost of increased complexity. The present paper shows the potential of the software greenius for the techno-economic evaluation of hybrid solar power plants and discusses two exemplary scenarios. Depreciated Concentrated Solar Power (CSP) plants based on trough technology can be retrofitted with solar towers in order to reach higher steam cycle temperatures and hence efficiencies. Compared to a newly built tower plant the hybridization of a depreciated trough plant causes about 30% lower LCOE reaching 104 /MWh. The second hybrid scenario combines cost-efficient photovoltaics with dispatchable CSP technology. This hybrid plant offers very high capacity factors up to 69% based on 100% load from 8am to 11pm. The LCOE of the hybrid plant are only slightly lower (174 vs. 186 /MWh) compared to the pure CSP plant because the capital expenditure for thermal storage and power block remains the same while the electricity output is much lower.

14 CFR 29.1435 - Hydraulic systems.

Code of Federal Regulations, 2011 CFR

2011-01-01

... hydraulic system must be designed to withstand pressures sufficiently greater than those prescribed in... must be means to indicate the pressure in each main hydraulic power system. (4) There must be means to... detrimental transient (surge) pressures during operation must be considered. (5) Each hydraulic line, fitting...

14 CFR 29.1435 - Hydraulic systems.

Code of Federal Regulations, 2012 CFR

2012-01-01

... hydraulic system must be designed to withstand pressures sufficiently greater than those prescribed in... must be means to indicate the pressure in each main hydraulic power system. (4) There must be means to... detrimental transient (surge) pressures during operation must be considered. (5) Each hydraulic line, fitting...

Rapid hydraulic recovery in Eucalyptus pauciflora after drought: linkages between stem hydraulics and leaf gas exchange.

PubMed

Martorell, Sebastià; Diaz-Espejo, Antonio; Medrano, Hipólito; Ball, Marilyn C; Choat, Brendan

2014-03-01

In woody plants, photosynthetic capacity is closely linked to rates at which the plant hydraulic system can supply water to the leaf surface. Drought-induced embolism can cause sharp declines in xylem hydraulic conductivity that coincide with stomatal closure and reduced photosynthesis. Recovery of photosynthetic capacity after drought is dependent on restored xylem function, although few data exist to elucidate this coordination. We examined the dynamics of leaf gas exchange and xylem function in Eucalyptus pauciflora seedlings exposed to a cycle of severe water stress and recovery after re-watering. Stomatal closure and leaf turgor loss occurred at water potentials that delayed the extensive spread of embolism through the stem xylem. Stem hydraulic conductance recovered to control levels within 6 h after re-watering despite a severe drought treatment, suggesting an active mechanism embolism repair. However, stomatal conductance did not recover after 10 d of re-watering, effecting tighter control of transpiration post drought. The dynamics of recovery suggest that a combination of hydraulic and non-hydraulic factors influenced stomatal behaviour post drought. © 2013 John Wiley & Sons Ltd.

Effect of nuclear power on CO₂ emission from power plant sector in Iran.

PubMed

Kargari, Nargess; Mastouri, Reza

2011-01-01

It is predicted that demand for electricity in Islamic Republic of Iran will continue to increase dramatically in the future due to the rapid pace of economic development leading to construction of new power plants. At the present time, most of electricity is generated by burning fossil fuels which result in emission of great deal of pollutants and greenhouse gases (GHG) such as SO₂, NOx, and CO₂. The power industry is the largest contributor to these emissions. Due to minimal emission of GHG by renewable and nuclear power plants, they are most suitable replacements for the fossil-fueled power plants. However, the nuclear power plants are more suitable than renewable power plants in providing baseload electricity. The Bushehr Nuclear Power Plant, the only nuclear power plant of Iran, is expected to start operation in 2010. This paper attempts to interpret the role of Bushehr nuclear power plant (BNPP) in CO₂ emission trend of power plant sector in Iran. In order to calculate CO₂ emissions from power plants, National CO₂ coefficients have been used. The National CO₂ emission coefficients are according to different fuels (natural gas, fuels gas, fuel oil). By operating Bushehr Nuclear Power Plant in 2010, nominal capacity of electricity generation in Iran will increase by about 1,000 MW, which increases the electricity generation by almost 7,000 MWh/year (it is calculated according to availability factor and nominal capacity of BNPP). Bushehr Nuclear Power Plant will decrease the CO₂ emission in Iran power sector, by about 3% in 2010.

Hydrogen production at hydro-power plants

NASA Astrophysics Data System (ADS)

Tarnay, D. S.

A tentative design for hydrogen-producing installations at hydropower facilities is discussed from technological, economic and applications viewpoints. The plants would use alternating current to electrolyze purified river water. The hydrogen would be stored in gas or liquid form and oxygen would be sold or vented to the atmosphere. The hydrogen could later be burned in a turbine generator for meeting peak loads, either in closed or open cycle systems. The concept would allow large hydroelectric plants to function in both base- and peak-load modes, thus increasing the hydraulic utilization of the plant and the capacity factor to a projected 0.90. Electrolyzer efficiencies ranging from 0.85-0.90 have been demonstrated. Excess hydrogen can be sold for other purposes or, eventually, as domestic and industrial fuel, at prices competitive with current industrial hydrogen.

FOREWORD: The XXV IAHR Symposium on Hydraulic Machinery and Systems marks half a century tradition

NASA Astrophysics Data System (ADS)

Susan-Resiga, Romeo

2010-05-01

IAHR75_logoUPT90_logoARFT_logo International Association of Hydro-Environment Engineering and Research'Politehnica' University of TimisoaraRomanian Academy - Timisoara Branch The 25th edition of the IAHR Symposium on Hydraulic Machinery and Systems, held in Timisoara, Romania, 20-24 September 2010, jointly organized by the 'Politehnica' University of Timisoara and the Romanian Academy - Timisoara Branch, marks a half century tradition of these prestigious symposia. However, it is the first time that Romania hosts such a symposium, and for good reasons. The Romanian electrical power system has a total of 20,630 MW installed power, out of which 6,422 MW in hydropower plants. The energy produced in hydropower facilities was in 2008 of 17,105 GWh from a total of 64,772 GWh electrical energy production. Moreover, for the period 2009-2015, new hydropower capacities are going to be developed, with a total of 2,157 MW installed power and an estimated 5,770 GWh/year energy production. Within the same period of time, the refurbishment, modernization and repair programs will increase the actual hydropower production with an estimated 349 GWh/year. The 'Politehnica' University of Timisoara is proud to host the 25th IAHR Symposium on Hydraulic Machinery and Systems, in the year of its 90th anniversary. The 'Politehnica' University of Timisoara is one of the largest and most well-known technical universities from Central and Eastern Europe. It was founded in 1920, a short time after the union into one state of all the Romanian territories, following the end of the First World War, in order to respond to the need engineers felt by the Romanian society at that time, within the economical development framework. During its 90 years of existence, 'Politehnica' University of Timisoara educated over 100,000 engineers, greatly appreciated both in Romania and abroad, for their competence and seriousness. King Ferdinand I of Romania said while visiting the recently established

46 CFR 112.50-3 - Hydraulic starting.

Code of Federal Regulations, 2013 CFR

2013-10-01

... 46 Shipping 4 2013-10-01 2013-10-01 false Hydraulic starting. 112.50-3 Section 112.50-3 Shipping... POWER SYSTEMS Emergency Diesel and Gas Turbine Engine Driven Generator Sets § 112.50-3 Hydraulic starting. A hydraulic starting system must meet the following: (a) The hydraulic starting system must be a...

46 CFR 112.50-3 - Hydraulic starting.

Code of Federal Regulations, 2012 CFR

2012-10-01

... 46 Shipping 4 2012-10-01 2012-10-01 false Hydraulic starting. 112.50-3 Section 112.50-3 Shipping... POWER SYSTEMS Emergency Diesel and Gas Turbine Engine Driven Generator Sets § 112.50-3 Hydraulic starting. A hydraulic starting system must meet the following: (a) The hydraulic starting system must be a...

46 CFR 112.50-3 - Hydraulic starting.

Code of Federal Regulations, 2014 CFR

2014-10-01

... 46 Shipping 4 2014-10-01 2014-10-01 false Hydraulic starting. 112.50-3 Section 112.50-3 Shipping... POWER SYSTEMS Emergency Diesel and Gas Turbine Engine Driven Generator Sets § 112.50-3 Hydraulic starting. A hydraulic starting system must meet the following: (a) The hydraulic starting system must be a...

Shoreham Nuclear Power Plant

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

NONE

1992-12-31

The United States Supreme Court, with PG&E and Silkwood, and in the eight years since, has expanded the acceptable extent of state regulation of commercial nuclear power plants. In PG&E, the Court established the acceptability of state regulation that purports to be concerned with the non-radiological aspects of nuclear plant operations but that, as a practical matter, is concerned with their radiological hazards. In Silkwood, the Court established the acceptability of state regulation of radiological hazards when its impact on federal regulation of radiological hazards is indirect and incidental. Finally, in Goodyear and English, the Court confirmed and elaborated onmore » such state regulation. Subject to political demands either for additional involvement in commercial nuclear power plant regulation or from political interests opposed altogether to nuclear power, some states, in the 1980s, sought to expand even further the involvement of state and local governments in nuclear plant regulation. Indeed, some states sought and in some instances acquired, through innovative and extraordinary means, a degree of involvement in the regulation of radiological hazards that seriously erodes and undermines the role of the federal government in such regulation. In particular, the State of New York concluded with the Long Island Lighting Company (LILCO), in February 1989, an agreement for the purchase of New York of the Shoreham nuclear power plant on Long Island. A response to failed efforts by New York to prevent the issuance by the NRC of a license to LILCO to operate the plant, the agreement was concluded to allow New York to close the plant either altogether or to convert it to a fossil fuel facility. The opposition to the sale of Shoreham is discussed.« less

Plant performance on Mediterranean green roofs: interaction of species-specific hydraulic strategies and substrate water relations.

PubMed

Raimondo, Fabio; Trifilò, Patrizia; Lo Gullo, Maria A; Andri, Sergio; Savi, Tadeja; Nardini, Andrea

2015-01-20

Recent studies have highlighted the ecological, economic and social benefits assured by green roof technology to urban areas. However, green roofs are very hostile environments for plant growth because of shallow substrate depths, high temperatures and irradiance and wind exposure. This study provides experimental evidence for the importance of accurate selection of plant species and substrates for implementing green roofs in hot and arid regions, like the Mediterranean area. Experiments were performed on two shrub species (Arbutus unedo L. and Salvia officinalis L.) grown in green roof experimental modules with two substrates slightly differing in their water retention properties, as derived from moisture release curves. Physiological measurements were performed on both well-watered and drought-stressed plants. Gas exchange, leaf and xylem water potential and also plant hydraulic conductance were measured at different time intervals following the last irrigation. The substrate type significantly affected water status. Arbutus unedo and S. officinalis showed different hydraulic responses to drought stress, with the former species being substantially isohydric and the latter one anisohydric. Both A. unedo and S. officinalis were found to be suitable species for green roofs in the Mediterranean area. However, our data suggest that appropriate choice of substrate is key to the success of green roof installations in arid environments, especially if anisohydric species are employed. Published by Oxford University Press on behalf of the Annals of Botany Company.

ESP IMPROVEMENTS AT POWER PLANTS

EPA Science Inventory

An on-going ORD and OIA collaborative project in the Newly Independent States (NIS) is designed to upgrade ESPs used in NIS power plants and has laid the foundation for implementing cost-effective ESP modernization efforts at power plants. Thus far, state-of-the-art ESP performan...

76 FR 77963 - Oglethorpe Power Corporation; Proposed Biomass Power Plant

Federal Register 2010, 2011, 2012, 2013, 2014

2011-12-15

... Service Oglethorpe Power Corporation; Proposed Biomass Power Plant AGENCY: Rural Utilities Service, USDA... construction of a 100 megawatt (MW) biomass plant and related facilities (Proposal) in Warren County, Georgia...

Development of heat sink concept for near-term fusion power plant divertor

NASA Astrophysics Data System (ADS)

Rimza, Sandeep; Khirwadkar, Samir; Velusamy, Karupanna

2017-04-01

Development of an efficient divertor concept is an important task to meet in the scenario of the future fusion power plant. The divertor, which is a vital part of the reactor has to discharge the considerable fraction of the total fusion thermal power (∼15%). Therefore, it has to survive very high thermal fluxes (∼10 MW/m2). In the present paper, an efficient divertor heat exchanger cooled by helium is proposed for the fusion tokamak. The Plasma facing surface of divertor made-up of several modules to overcome the stresses caused by high heat flux. The thermal hydraulic performance of one such module is numerically investigated in the present work. The result shows that the proposed design is capable of handling target heat flux values of 10 MW/m2. The computational model has been validated against high-heat flux experiments and a satisfactory agreement is noticed between the present simulation and the reported results.

Dispatchable Solar Power Plant Project

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

Price, Henry

As penetration of intermittent renewable power increases, grid operators must manage greater variability in the supply and demand on the grid. One result is that utilities are planning to build many new natural gas peaking power plants that provide added flexibility needed for grid management. This report discusses the development of a dispatchable solar power (DSP) plant that can be used in place of natural gas peakers. Specifically, a new molten-salt tower (MST) plant has been developed that is designed to allow much more flexible operation than typically considered in concentrating solar power plants. As a result, this plant canmore » provide most of the capacity and ancillary benefits of a conventional natural gas peaker plant but without the carbon emissions. The DSP system presented was designed to meet the specific needs of the Arizona Public Service (APS) utility 2017 peaking capacity request for proposals (RFP). The goal of the effort was to design a MST peaker plant that had the operational capabilities required to meet the peaking requirements of the utility and be cost competitive with the natural gas alternative. The effort also addresses many perceived barriers facing the commercial deployment of MST technology in the US today. These include MST project development issues such as permitting, avian impacts, visual impacts of tower CSP projects, project schedule, and water consumption. The DSP plant design is based on considerable analyses using sophisticated solar system design tools and in-depth preliminary engineering design. The resulting DSP plant design uses a 250 MW steam power cycle, with solar field designed to fit on a square mile plot of land that has a design point thermal rating of 400 MWt. The DSP plant has an annual capacity factor of about 16% tailored to deliver greater than 90% capacity during the critical Arizona summer afternoon peak. The table below compares the All-In energy cost and capacity payment of conventional combustion

Hydraulic integration and shrub growth form linked across continental aridity gradients

Treesearch

H. Jochen Schenk; Christine M. Goedhart; Marisa Nordenstahl; Hugo I. Martinez Cabrera; Cynthia S. Jones

2008-01-01

Both engineered hydraulic systems and plant hydraulic systems are protected against failure by resistance, reparability, and redundancy. A basic rule of reliability engineering is that the level of independent redundancy should increase with increasing risk of fatal system failure. Here we show that hydraulic systems of plants function as predicted by this engineering...

Modelling of nuclear power plant decommissioning financing.

PubMed

Bemš, J; Knápek, J; Králík, T; Hejhal, M; Kubančák, J; Vašíček, J

2015-06-01

Costs related to the decommissioning of nuclear power plants create a significant financial burden for nuclear power plant operators. This article discusses the various methodologies employed by selected European countries for financing of the liabilities related to the nuclear power plant decommissioning. The article also presents methodology of allocation of future decommissioning costs to the running costs of nuclear power plant in the form of fee imposed on each megawatt hour generated. The application of the methodology is presented in the form of a case study on a new nuclear power plant with installed capacity 1000 MW. © The Author 2015. Published by Oxford University Press. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

Effect of heating strategy on power consumption and performance of a pilot plant anaerobic digester.

PubMed

Espinosa-Solares, Teodoro; Valle-Guadarrama, Salvador; Bombardiere, John; Domaschko, Max; Easter, Michael

2009-05-01

The effect of heating strategy on power consumption and performance of a pilot plant anaerobic digester treating chicken litter, under thermophilic conditions, has been studied. Heating strategy was evaluated using three different spans (0.2 degrees C, 0.6 degrees C, and 1.0 degree C) for triggering the temperature control system from target temperature (56.7 degrees C). The hydraulic retention time in the pilot plant digester was in the range of 32 to 37 days, varying the total solids concentration fed from 5% to 6%. The results showed that under the experimental conditions, heating was the most energy-demanding process with 95.5% of the energy used. Increments up to 7.5% and 3.8%, respectively, on mechanical and heating power consumption, were observed as the span, for triggering the temperature control system from target temperature, was increased. Under the experimental conditions studied here, an increment of 30.6% on the global biodigester performance index was observed when a span of 1.0 degree C was compared to the one of 0.2 degrees C.

Entropy production and optimization of geothermal power plants

NASA Astrophysics Data System (ADS)

Michaelides, Efstathios E.

2012-09-01

Geothermal power plants are currently producing reliable and low-cost, base load electricity. Three basic types of geothermal power plants are currently in operation: single-flashing, dual-flashing, and binary power plants. Typically, the single-flashing and dual-flashing geothermal power plants utilize geothermal water (brine) at temperatures in the range of 550-430 K. Binary units utilize geothermal resources at lower temperatures, typically 450-380 K. The entropy production in the various components of the three types of geothermal power plants determines the efficiency of the plants. It is axiomatic that a lower entropy production would improve significantly the energy utilization factor of the corresponding power plant. For this reason, the entropy production in the major components of the three types of geothermal power plants has been calculated. It was observed that binary power plants generate the lowest amount of entropy and, thus, convert the highest rate of geothermal energy into mechanical energy. The single-flashing units generate the highest amount of entropy, primarily because they re-inject fluid at relatively high temperature. The calculations for entropy production provide information on the equipment where the highest irreversibilities occur, and may be used to optimize the design of geothermal processes in future geothermal power plants and thermal cycles used for the harnessing of geothermal energy.

Proceedings of the 7th International Meeting on Nuclear Reactor Thermal-Hydraulics NURETH-7. Volume 3, Sessions 12-16

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

Block, R.C.; Feiner, F.

This document, Volume 3, includes papers presented at the 7th International Meeting on Nuclear Reactor Thermal-Hydraulics (NURETH-7) September 10--15, 1995 at Saratoga Springs, N.Y. The following subjects are discussed: Progress in analytical and experimental work on the fundamentals of nuclear thermal-hydraulics, the development of advanced mathematical and numerical methods, ad the application of advancements in the field in the development of novel reactor concepts. Also combined issues of thermal-hydraulics and reactor/power-plant safety, core neutronics and/or radiation. Selected abstracts have been indexed separately for inclusion in the Energy Science and Technology Database.

Concentrating Solar Power Projects - Gemasolar Thermosolar Plant |

Science.gov Websites

Concentrating Solar Power | NREL Gemasolar Thermosolar Plant This page provides information on Gemasolar Thermosolar Plant, a concentrating solar power (CSP) project, with data organized by background , participants, and power plant configuration. Gemasolar is the first high-temperature solar receiver with molten

Phase 1 Feasibility Study: Seawater Hydraulic Transfer Pump

DTIC Science & Technology

1996-11-01

2442532 3408040 M/ DIRECT HYDRAULIC DRIVE FOR LARGE FLOTATION CELLS 2440714 3406737 A-5 M/ COMBINED ANTISKID AND TRACTION CONTROL ELECTRONIC BRAKE SYSTEM ...HYDRAULIC PRESSURE 2449168 3412870 M/ POWER STEERING PUMP WITH BALANCED PORTING 2446911 3411257 M/ HYDRAULIC BRAKE SYSTEM INCLUDING SLIP CONTROL ...2440401 3406424 M/ HYDRAULIC CIRCUIT FOR RUNNING A CRAWLER VEHICLE 2434313 3402015 M/ HYDRAULICALLY ACTUATED AIRCRAFT ENGINE CONTROL SYSTEM 2425918

An experimental aluminum-fueled power plant

NASA Astrophysics Data System (ADS)

Vlaskin, M. S.; Shkolnikov, E. I.; Bersh, A. V.; Zhuk, A. Z.; Lisicyn, A. V.; Sorokovikov, A. I.; Pankina, Yu. V.

2011-10-01

An experimental co-generation power plant (CGPP-10) using aluminum micron powder (with average particle size up to 70 μm) as primary fuel and water as primary oxidant was developed and tested. Power plant can work in autonomous (unconnected from industrial network) nonstop regime producing hydrogen, electrical energy and heat. One of the key components of experimental plant is aluminum-water high-pressure reactor projected for hydrogen production rate of ∼10 nm3 h-1. Hydrogen from the reactor goes through condenser and dehumidifier and with -25 °C dew-point temperature enters into the air-hydrogen fuel cell 16 kW-battery. From 1 kg of aluminum the experimental plant produces 1 kWh of electrical energy and 5-7 kWh of heat. Power consumer gets about 10 kW of electrical power. Plant electrical and total efficiencies are 12% and 72%, respectively.

Abscisic Acid Regulation of Root Hydraulic Conductivity and Aquaporin Gene Expression Is Crucial to the Plant Shoot Growth Enhancement Caused by Rhizosphere Humic Acids.

PubMed

Olaetxea, Maite; Mora, Verónica; Bacaicoa, Eva; Garnica, María; Fuentes, Marta; Casanova, Esther; Zamarreño, Angel M; Iriarte, Juan C; Etayo, David; Ederra, Iñigo; Gonzalo, Ramón; Baigorri, Roberto; García-Mina, Jose M

2015-12-01

The physiological and metabolic mechanisms behind the humic acid-mediated plant growth enhancement are discussed in detail. Experiments using cucumber (Cucumis sativus) plants show that the shoot growth enhancement caused by a structurally well-characterized humic acid with sedimentary origin is functionally associated with significant increases in abscisic acid (ABA) root concentration and root hydraulic conductivity. Complementary experiments involving a blocking agent of cell wall pores and water root transport (polyethylenglycol) show that increases in root hydraulic conductivity are essential in the shoot growth-promoting action of the model humic acid. Further experiments involving an inhibitor of ABA biosynthesis in root and shoot (fluridone) show that the humic acid-mediated enhancement of both root hydraulic conductivity and shoot growth depended on ABA signaling pathways. These experiments also show that a significant increase in the gene expression of the main root plasma membrane aquaporins is associated with the increase of root hydraulic conductivity caused by the model humic acid. Finally, experimental data suggest that all of these actions of model humic acid on root functionality, which are linked to its beneficial action on plant shoot growth, are likely related to the conformational structure of humic acid in solution and its interaction with the cell wall at the root surface. © 2015 American Society of Plant Biologists. All Rights Reserved.

Fuel cell power plant economic and operational considerations

NASA Technical Reports Server (NTRS)

Lance, J. R.

1984-01-01

Fuel cell power plants intended for electric utility and cogeneration applications are now in the design and construction stage. This paper describes economic and operational considerations being used in the development and design of plants utilizing air cooled phosphoric acid fuel cells. Fuel cell power plants have some unique characteristics relative to other types of power plants. As a result it was necessary to develop specific definitions of the fuel cell power plant characteristics in order to perform cost of electricity calculations. This paper describes these characteristics and describes the economic analyses used in the Westinghouse fuel cell power plant program.

Power Plant Model Validation Tool

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

The PPMV is used to validate generator model using disturbance recordings. The PPMV tool contains a collection of power plant models and model validation studies, as well as disturbance recordings from a number of historic grid events. The user can import data from a new disturbance into the database, which converts PMU and SCADA data into GE PSLF format, and then run the tool to validate (or invalidate) the model for a specific power plant against its actual performance. The PNNL PPMV tool enables the automation of the process of power plant model validation using disturbance recordings. The tool usesmore » PMU and SCADA measurements as input information. The tool automatically adjusts all required EPCL scripts and interacts with GE PSLF in the batch mode. The main tool features includes: The tool interacts with GE PSLF; The tool uses GE PSLF Play-In Function for generator model validation; Database of projects (model validation studies); Database of the historic events; Database of the power plant; The tool has advanced visualization capabilities; and The tool automatically generates reports« less

Stomatal control and hydraulic conductance, with special reference to tall trees.

PubMed

Franks, Peter J

2004-08-01

A better understanding of the mechanistic basis of stomatal control is necessary to understand why modes of stomatal response differ among individual trees, and to improve the theoretical foundation for predictive models and manipulative experiments. Current understanding of the mechanistic basis of stomatal control is reviewed here and discussed in relation to the plant hydraulic system. Analysis focused on: (1) the relative role of hydraulic conductance in the vicinity of the stomatal apparatus versus whole-plant hydraulic conductance; (2) the influence of guard cell inflation characteristics and the mechanical interaction between guard cells and epidermal cells; and (3) the system requirements for moderate versus dramatic reductions in stomatal conductance with increasing evaporation potential. Special consideration was given to the potential effect of changes in hydraulic properties as trees grow taller. Stomatal control of leaf gas exchange is coupled to the entire plant hydraulic system and the basis of this coupling is the interdependence of guard cell water potential and transpiration rate. This hydraulic feedback loop is always present, but its dynamic properties may be altered by growth or cavitation-induced changes in hydraulic conductance, and may vary with genetically related differences in hydraulic conductances. Mechanistic models should include this feedback loop. Plants vary in their ability to control transpiration rate sufficiently to maintain constant leaf water potential. Limited control may be achieved through the hydraulic feedback loop alone, but for tighter control, an additional element linking transpiration rate to guard cell osmotic pressure may be needed.

System Simulation of Nuclear Power Plant by Coupling RELAP5 and Matlab/Simulink

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

Meng Lin; Dong Hou; Zhihong Xu

2006-07-01

Since RELAP5 code has general and advanced features in thermal-hydraulic computation, it has been widely used in transient and accident safety analysis, experiment planning analysis, and system simulation, etc. So we wish to design, analyze, verify a new Instrumentation And Control (I and C) system of Nuclear Power Plant (NPP) based on the best-estimated code, and even develop our engineering simulator. But because of limited function of simulating control and protection system in RELAP5, it is necessary to expand the function for high efficient, accurate, flexible design and simulation of I and C system. Matlab/Simulink, a scientific computation software, justmore » can compensate the limitation, which is a powerful tool in research and simulation of plant process control. The software is selected as I and C part to be coupled with RELAP5 code to realize system simulation of NPPs. There are two key techniques to be solved. One is the dynamic data exchange, by which Matlab/Simulink receives plant parameters and returns control results. Database is used to communicate the two codes. Accordingly, Dynamic Link Library (DLL) is applied to link database in RELAP5, while DLL and S-Function is applied in Matlab/Simulink. The other problem is synchronization between the two codes for ensuring consistency in global simulation time. Because Matlab/Simulink always computes faster than RELAP5, the simulation time is sent by RELAP5 and received by Matlab/Simulink. A time control subroutine is added into the simulation procedure of Matlab/Simulink to control its simulation advancement. Through these ways, Matlab/Simulink is dynamically coupled with RELAP5. Thus, in Matlab/Simulink, we can freely design control and protection logic of NPPs and test it with best-estimated plant model feedback. A test will be shown to illuminate that results of coupling calculation are nearly the same with one of single RELAP5 with control logic. In practice, a real Pressurized Water Reactor (PWR

Free-piston regenerative hot gas hydraulic engine

NASA Technical Reports Server (NTRS)

Beremand, D. G. (Inventor)

1980-01-01

A displacer piston which is driven pneumatically by a high-pressure or low-pressure gas is included in a free-piston regenerative hydraulic engine. Actuation of the displacer piston circulates the working fluid through a heater, a regenerator and a cooler. The present invention includes an inertial mass such as a piston or a hydraulic fluid column to effectively store and supply energy during portions of the cycle. Power is transmitted from the working fluid to a hydraulic fluid across a diaphragm or lightweight piston to achieve a hydraulic power out-put. The displacer piston of the present invention may be driven pneumatically, hydraulically or electromagnetically. In addition, the displacer piston and the inertial mass of the present invention may be positioned on the same side of the diaphragm member or may be separated by the diaphragm member.

Optimizing the Utility Power of a Geothermal Power Plant using Variable Frequency Drive (VFD) (Case Study: Sibayak Geothermal Power Plant)

NASA Astrophysics Data System (ADS)

Sinaga, R. H. M.; Manik, Y.

2018-03-01

Sibayak Geothermal Power Plant (SGPP) is one of the plants being developed by Pertamina Geothermal Energy (PGE) at the upstream phase. At the downstream phase, State - owned Electricity Company (PLN) through PT. Dizamatra Powerindo is the developer. The gross capacity of the power plant is 13.3 MW, consisting 1 unit of Monoblock (2 MW) developed by PGE and 2 units (2×5.65 MW) operated through Energy Sales Contract by PLN. During the development phase of a geothermal power plant, there is a chance to reduce the utility power in order to increase the overall plant efficiency. Reducing the utility power can be attempted by utilizing the wet bulb temperature fluctuation. In this study, a modeling process is developed by using Engineering Equation Solver (EES) software version 9.430. The possibility of energy saving is indicated by condenser pressure changes as a result of wet bulb temperature fluctuation. The result of this study indicates that the change of condenser pressure is about 50.8% on the constant liquid/gas (L/G) condition of the wet bulb temperature of 15°C to 25°C. Further result indicates that in this power plant, Cooling Tower Fan (CTF) is the facility that has the greatest utility load, followed by Hot Well Pump (HWP). The saving of the greatest utility load is applied trough Variable Frequency Drive (VFD) instrumentation. The result of this modeling has been validated by actual operations data (log sheet). The developed model has also been reviewed trough Specific Steam Consumption (SSC), resulting that constant L/G condition allows the optimum condition on of the wet bulb temperature of 15°C to 25°C.

76 FR 20624 - Oglethorpe Power Corporation: Proposed Biomass Power Plant

Federal Register 2010, 2011, 2012, 2013, 2014

2011-04-13

... DEPARTMENT OF AGRICULTURE Rural Utilities Service Oglethorpe Power Corporation: Proposed Biomass Power Plant AGENCY: Rural Utilities Service, USDA. ACTION: Notice of Availability of a Draft...) biomass plant and related facilities (Proposal) in Warren County, Georgia. The purpose of the Proposal is...

Portable Hydraulic Powerpack

NASA Technical Reports Server (NTRS)

Anderson, L. A.; Henry, R. L.; Fedor, O. H.; Owens, L. J.

1986-01-01

Rechargeable hydraulic powerpack functions as lightweight, compact source of mechanical energy. Self-contained hydraulic powerpack derives energy from solid chemical charge. Combustion of charge initiated by small hammer, and revolving feeder replaces charges expended. Combustion gases cool during expansion in turbine and not too hot for release to atmosphere. Unit has applications driving wheelchairs and operating drills, winches, and other equipment in remote areas. Also replaces electric motors and internal-combustion engines as source of power in explosive atmospheres.

Mobile Nuclear Power Plants 1960-1970

DTIC Science & Technology

1960-11-01

power for electricity for the Army in the Field cannot be realized until a satisfactory electri- cal power distribution system is developed or low...power plants in the 1960-70 period should be to provide electri- cal power to meet concentrated demands such as those im- posed by Army and Corps...Capital Letter - Order of initiation of field plants whoa« deslg- nationa do not Include thia final letter are prototype or pilot planta

Tribology of hydraulic pumps

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

Yamaguchi, A.

To obtain much higher performance than that of alternative power transmission systems, hydraulic systems have been continuously evolving to use high-pressure. Adoption of positive displacement pumps and motors is based on this reason. Therefore, tribology is a key terminology for hydraulic pumps and motors to obtain excellent performance and durability. In this paper the following topics are investigated: (1) the special feature of tribology of hydraulic pumps and motors; (2) indication of the important bearing/sealing parts in piston pumps and effects of the frictional force and leakage flow to performance; (3) the methods to break through the tribological limitation ofmore » hydraulic equipment; and (4) optimum design of the bearing/sealing parts used in the fluid to mixed lubrication regions.« less

Power Plant Construction

NASA Technical Reports Server (NTRS)

1985-01-01

Stone & Webster Engineering Corporation utilized TAP-A, a COSMIC program originally developed as part of a NASA investigation into the potential of nuclear power for space launch vehicles. It is useful in nuclear power plant design to qualify safety-related equipment at the temperatures it would experience should an accident occur. The program is easy to use, produces accurate results, and is inexpensive to run.

The 125 MW Upper Mahiao geothermal power plant

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

Forte, N.

1996-12-31

The 125 MW Upper Mahiao power plant, the first geothermal power project to be financed under a Build-Own-Operate-and-Transfer (BOOT) arrangement in the Philippines, expected to complete its start-up testing in August of this year. This plant uses Ormat`s environmentally benign technology and is both the largest geothermal steam/binary combined cycle plant as well as the largest geothermal power plant utilizing air cooled condensers. The Ormat designed and constructed plant was developed under a fast track program, with some two years from the April 1994 contract signing through design, engineering, construction and startup. The plant is owned and operated by amore » subsidiary of CalEnergy Co., Inc. and supplies power to PNOC-Energy Development Corporation for the National Power Corporation (Napocor) national power grid in the Philippines.« less

A test of the hydraulic vulnerability segmentation hypothesis in angiosperm and conifer tree species

DOE PAGES

Johnson, Daniel M.; Wortemann, Remi; McCulloh, Katherine A.; ...

2016-05-04

Water transport from soils to the atmosphere is critical for plant growth and survival. However, we have a limited understanding about many portions of the whole-tree hydraulic pathway, because the vast majority of published information is on terminal branches. Our understanding of mature tree trunk hydraulic physiology, in particular, is limited. The hydraulic vulnerability segmentation hypothesis (HVSH) stipulates that distal portions of the plant (leaves, branches and roots) should be more vulnerable to embolism than trunks, which are non-redundant organs that require a massive carbon investment. In the current study, we compared vulnerability to loss of hydraulic function, leaf andmore » xylem water potentials and the resulting hydraulic safety margins (in relation to the water potential causing 50% loss of hydraulic conductivity) in leaves, branches, trunks and roots of four angiosperms and four conifer tree species. Across all species, our results supported strongly the HVSH as leaves and roots were less resistant to embolism than branches or trunks. However, branches were consistently more resistant to embolism than any other portion of the plant, including trunks. Also, calculated whole-tree vulnerability to hydraulic dysfunction was much greater than vulnerability in branches. This was due to hydraulic dysfunction in roots and leaves at less negative water potentials than those causing branch or trunk dysfunction. Leaves and roots had narrow or negative hydraulic safety margins, but trunks and branches maintained positive safety margins. By using branch-based hydraulic information as a proxy for entire plants, much research has potentially overestimated embolism resistance, and possibly drought tolerance, for many species. This study highlights the necessity to reconsider past conclusions made about plant resistance to drought based on branch xylem only. As a result, this study also highlights the necessity for more research of whole-plant hydraulic

A test of the hydraulic vulnerability segmentation hypothesis in angiosperm and conifer tree species

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

Johnson, Daniel M.; Wortemann, Remi; McCulloh, Katherine A.

Water transport from soils to the atmosphere is critical for plant growth and survival. However, we have a limited understanding about many portions of the whole-tree hydraulic pathway, because the vast majority of published information is on terminal branches. Our understanding of mature tree trunk hydraulic physiology, in particular, is limited. The hydraulic vulnerability segmentation hypothesis (HVSH) stipulates that distal portions of the plant (leaves, branches and roots) should be more vulnerable to embolism than trunks, which are non-redundant organs that require a massive carbon investment. In the current study, we compared vulnerability to loss of hydraulic function, leaf andmore » xylem water potentials and the resulting hydraulic safety margins (in relation to the water potential causing 50% loss of hydraulic conductivity) in leaves, branches, trunks and roots of four angiosperms and four conifer tree species. Across all species, our results supported strongly the HVSH as leaves and roots were less resistant to embolism than branches or trunks. However, branches were consistently more resistant to embolism than any other portion of the plant, including trunks. Also, calculated whole-tree vulnerability to hydraulic dysfunction was much greater than vulnerability in branches. This was due to hydraulic dysfunction in roots and leaves at less negative water potentials than those causing branch or trunk dysfunction. Leaves and roots had narrow or negative hydraulic safety margins, but trunks and branches maintained positive safety margins. By using branch-based hydraulic information as a proxy for entire plants, much research has potentially overestimated embolism resistance, and possibly drought tolerance, for many species. This study highlights the necessity to reconsider past conclusions made about plant resistance to drought based on branch xylem only. As a result, this study also highlights the necessity for more research of whole-plant hydraulic

Vehicle having hydraulic and power steering systems using a single high pressure pump

DOEpatents

Bartley, Bradley E.; Blass, James R.; Gibson, Dennis H.

2001-06-22

A vehicle comprises a plurality of wheels attached to a vehicle housing. Also attached to the vehicle housing is a power steering system, including a fluid flow circuit, which is operably coupled to a number of the wheels. An internal combustion engine attached to the vehicle housing is connected to a hydraulically actuated system that includes a high pressure pump. An outlet of the high pressure pump is in fluid communication with the fluid flow circuit.

Geothermal Power Generation Plant

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

Boyd, Tonya

2013-12-01

Oregon Institute of Technology (OIT) drilled a deep geothermal well on campus (to 5,300 feet deep) which produced 196°F resource as part of the 2008 OIT Congressionally Directed Project. OIT will construct a geothermal power plant (estimated at 1.75 MWe gross output). The plant would provide 50 to 75 percent of the electricity demand on campus. Technical support for construction and operations will be provided by OIT’s Geo-Heat Center. The power plant will be housed adjacent to the existing heat exchange building on the south east corner of campus near the existing geothermal production wells used for heating campus. Coolingmore » water will be supplied from the nearby cold water wells to a cooling tower or air cooling may be used, depending upon the type of plant selected. Using the flow obtained from the deep well, not only can energy be generated from the power plant, but the “waste” water will also be used to supplement space heating on campus. A pipeline will be construction from the well to the heat exchanger building, and then a discharge line will be construction around the east and north side of campus for anticipated use of the “waste” water by facilities in an adjacent sustainable energy park. An injection well will need to be drilled to handle the flow, as the campus existing injection wells are limited in capacity.« less

Generalized hydromechanical model for stomatal responses to hydraulic perturbations.

PubMed

Kwon, H W; Choi, M Y

2014-01-07

Stomata respond in a common pattern to various hydraulic perturbations on any part of the 'soil-plant-air' system: initial transient 'wrong-way' responses and final stationary 'right-way' responses. In order to describe this pattern on the basis of statistical physics, we propose a simple model where turgor pressure of a cell is taken to be a power function of its volume, and obtain results in qualitative agreement with experimental data for responses to a variety of hydraulic perturbations: Firstly, stationary stomatal conductance as a function of the vapor pressure deficit divides into three regimes characterized by sensitivities of the stomatal conductance and the transpiration rate with respect to vapor pressure deficit; secondly, for every hydraulic perturbation, the initial transient 'wrong-way' responses always appear; thirdly, on condition that water is supplied insufficiently, stomatal oscillations are often observed; finally, stomatal responses following leaf excision exhibit, after the initial transient wrong-way responses, slow relaxation to stomatal closing. In particular, comparison of areoles having different numbers of stomata demonstrates that areoles with small numbers of stomata tend to provoke lack of water in the soil as well as in the plant. In addition, our model also describes well dependence of the stomatal conductance on temperature. It may be extended further to describe stomatal responses to other environmental factors such as carbon dioxide, light, and temperature. © 2013 Elsevier Ltd. All rights reserved.

Oxygen-enriched air for MHD power plants

NASA Technical Reports Server (NTRS)

Ebeling, R. W., Jr.; Cutting, J. C.; Burkhart, J. A.

1979-01-01

Cryogenic air-separation process cycle variations and compression schemes are examined. They are designed to minimize net system power required to supply pressurized, oxygen-enriched air to the combustor of an MHD power plant with a coal input of 2000 MWt. Power requirements and capital costs for oxygen production and enriched air compression for enrichment levels from 13 to 50% are determined. The results are presented as curves from which total compression power requirements can be estimated for any desired enrichment level at any delivery pressure. It is found that oxygen enrichment and recuperative heating of MHD combustor air to 1400 F yields near-term power plant efficiencies in excess of 45%. A minimum power compression system requires 167 MW to supply 330 lb of oxygen per second and costs roughly 100 million dollars. Preliminary studies show MHD/steam power plants to be competitive with plants using high-temperature air preheaters burning gas.

Hydraulics. FOS: Fundamentals of Service.

ERIC Educational Resources Information Center

John Deere Co., Moline, IL.

This manual on hydraulics is one of a series of power mechanics texts and visual aids for training in the servicing of agricultural and industrial machinery. Focus is on oil hydraulics. Materials provide basic information and illustrations for use by vocational students and teachers as well as shop servicemen and laymen. The twelve chapters focus…

Optimization of hydraulic turbine governor parameters based on WPA

NASA Astrophysics Data System (ADS)

Gao, Chunyang; Yu, Xiangyang; Zhu, Yong; Feng, Baohao

2018-01-01

The parameters of hydraulic turbine governor directly affect the dynamic characteristics of the hydraulic unit, thus affecting the regulation capacity and the power quality of power grid. The governor of conventional hydropower unit is mainly PID governor with three adjustable parameters, which are difficult to set up. In order to optimize the hydraulic turbine governor, this paper proposes wolf pack algorithm (WPA) for intelligent tuning since the good global optimization capability of WPA. Compared with the traditional optimization method and PSO algorithm, the results show that the PID controller designed by WPA achieves a dynamic quality of hydraulic system and inhibits overshoot.

Improving geothermal power plants with a binary cycle

NASA Astrophysics Data System (ADS)

Tomarov, G. V.; Shipkov, A. A.; Sorokina, E. V.

2015-12-01

The recent development of binary geothermal technology is analyzed. General trends in the introduction of low-temperature geothermal sources are summarized. The use of single-phase low-temperature geothermal fluids in binary power plants proves possible and expedient. The benefits of power plants with a binary cycle in comparison with traditional systems are shown. The selection of the working fluid is considered, and the influence of the fluid's physicochemical properties on the design of the binary power plant is discussed. The design of binary power plants is based on the chemical composition and energy potential of the geothermal fluids and on the landscape and climatic conditions at the intended location. Experience in developing a prototype 2.5 MW Russian binary power unit at Pauzhetka geothermal power plant (Kamchatka) is outlined. Most binary systems are designed individually for a specific location. Means of improving the technology and equipment at binary geothermal power plants are identified. One option is the development of modular systems based on several binary systems that employ the heat from the working fluid at different temperatures.

AUTOMOTIVE DIESEL MAINTENANCE 2. UNIT III, AUTOMATIC TRANSMISSIONS--HYDRAULICS (PART I).

ERIC Educational Resources Information Center

Human Engineering Inst., Cleveland, OH.

THIS MODULE OF A 25-MODULE COURSE IS DESIGNED TO INTRODUCE BASIC HYDRAULIC PRINCIPLES AND PROVIDE AN UNDERSTANDING OF HYDRAULIC TRANSMISSIONS USED IN DIESEL POWERED VEHICLES. TOPICS ARE WHY USE HYDRAULICS, REVIEWING BASIC PHYSICS LAWS IN RELATION TO HYDRAULICS, UNDERSTANDING THE HYDRAULIC SYSTEM, AND DEVELOPING A BASIC HYDRAULIC SYSTEM. THE MODULE…

Abscisic Acid Regulation of Root Hydraulic Conductivity and Aquaporin Gene Expression Is Crucial to the Plant Shoot Growth Enhancement Caused by Rhizosphere Humic Acids1

PubMed Central

Bacaicoa, Eva; Garnica, María; Fuentes, Marta; Casanova, Esther; Etayo, David; Ederra, Iñigo; Gonzalo, Ramón

2015-01-01

The physiological and metabolic mechanisms behind the humic acid-mediated plant growth enhancement are discussed in detail. Experiments using cucumber (Cucumis sativus) plants show that the shoot growth enhancement caused by a structurally well-characterized humic acid with sedimentary origin is functionally associated with significant increases in abscisic acid (ABA) root concentration and root hydraulic conductivity. Complementary experiments involving a blocking agent of cell wall pores and water root transport (polyethylenglycol) show that increases in root hydraulic conductivity are essential in the shoot growth-promoting action of the model humic acid. Further experiments involving an inhibitor of ABA biosynthesis in root and shoot (fluridone) show that the humic acid-mediated enhancement of both root hydraulic conductivity and shoot growth depended on ABA signaling pathways. These experiments also show that a significant increase in the gene expression of the main root plasma membrane aquaporins is associated with the increase of root hydraulic conductivity caused by the model humic acid. Finally, experimental data suggest that all of these actions of model humic acid on root functionality, which are linked to its beneficial action on plant shoot growth, are likely related to the conformational structure of humic acid in solution and its interaction with the cell wall at the root surface. PMID:26450705

From Plant Hydraulics to Ecohydrology: a Case Study of Water Limitation in Aspen Forests

NASA Astrophysics Data System (ADS)

Sperry, J.; Venturas, M.; Love, D.; Anderegg, W.; Mackay, D. S.

2017-12-01

How dry must it get to threaten a standing forest? We answered this question for aspen stands in Utah with a model that predicts tree gas exchange and water status by optimizing photosynthetic gain vs. hydraulic risk from xylem cavitation. The model was parameterized for 10 aspen stands from various elevations and mountain ranges in the state of Utah, USA. The 2016 growing season was simulated from site-specific micrometeorological data under shallow (0.5 m) vs. deep (2m) root depth scenarios starting at field capacity. The model predicted a water-limiting threshold for each stand, defined as the minimum water input required to maximize stand gas exchange. All but one stand was estimated to be near or above its threshold in 2016. In the majority of stands, spring soil moisture and summer rain fell far short of supplying the threshold requirement. Without additional water, these stands would suffer over 70% loss of tree hydraulic conductance and high mortality risk. These more water-demanding stands were predicted to rely on groundwater for 60-95% of their threshold supply. Groundwater dependence suggests a greater sensitivity to winter precipitation than to growing season conditions. All but the sparsest aspen stands would experience significant mortality risk from a 50% reduction in groundwater input. The aspen test case suggests a wider utility for linking plant hydraulics and hydrology.

Impact of soil texture and water availability on the hydraulic control of plant and grape-berry development

Treesearch

Sara Tramontini; Cornelis van Leeuwen; Jean-Christophe Domec; Agnès Destrac-Irvine; Cyril Basteau; Marco Vitali; Olaf Mosbach-Schulz; Claudio Lovisolo

2013-01-01

All components of the soil-plant-atmosphere (s-p-a) continuum are known to control berry quality in grapevine (Vitis vinifera L.) via ecophysiological interactions between water uptake by roots and water loss by leaves. The scope of the present work was to explore how the main hydraulic components of grapevine influence fruit quality through changes...

Water movement through plant roots - exact solutions of the water flow equation in roots with linear or exponential piecewise hydraulic properties

NASA Astrophysics Data System (ADS)

Meunier, Félicien; Couvreur, Valentin; Draye, Xavier; Zarebanadkouki, Mohsen; Vanderborght, Jan; Javaux, Mathieu

2017-12-01

In 1978, Landsberg and Fowkes presented a solution of the water flow equation inside a root with uniform hydraulic properties. These properties are root radial conductivity and axial conductance, which control, respectively, the radial water flow between the root surface and xylem and the axial flow within the xylem. From the solution for the xylem water potential, functions that describe the radial and axial flow along the root axis were derived. These solutions can also be used to derive root macroscopic parameters that are potential input parameters of hydrological and crop models. In this paper, novel analytical solutions of the water flow equation are developed for roots whose hydraulic properties vary along their axis, which is the case for most plants. We derived solutions for single roots with linear or exponential variations of hydraulic properties with distance to root tip. These solutions were subsequently combined to construct single roots with complex hydraulic property profiles. The analytical solutions allow one to verify numerical solutions and to get a generalization of the hydric behaviour with the main influencing parameters of the solutions. The resulting flow distributions in heterogeneous roots differed from those in uniform roots and simulations led to more regular, less abrupt variations of xylem suction or radial flux along root axes. The model could successfully be applied to maize effective root conductance measurements to derive radial and axial hydraulic properties. We also show that very contrasted root water uptake patterns arise when using either uniform or heterogeneous root hydraulic properties in a soil-root model. The optimal root radius that maximizes water uptake under a carbon cost constraint was also studied. The optimal radius was shown to be highly dependent on the root hydraulic properties and close to observed properties in maize roots. We finally used the obtained functions for evaluating the impact of root maturation

Effects of prolonged drought on stem non-structural carbohydrates content and post-drought hydraulic recovery in Laurus nobilis L.: The possible link between carbon starvation and hydraulic failure.

PubMed

Trifilò, Patrizia; Casolo, Valentino; Raimondo, Fabio; Petrussa, Elisa; Boscutti, Francesco; Lo Gullo, Maria Assunta; Nardini, Andrea

2017-11-01

Drought-induced tree decline is a complex event, and recent hypotheses suggest that hydraulic failure and carbon starvation are co-responsible for this process. We tested the possible role of non-structural carbohydrates (NSC) content on post-drought hydraulic recovery, to verify the hypothesis that embolism reversal represents a mechanistic link between carbon starvation and stem hydraulics. Measurements were performed in laurel plants subjected to similar water stress levels either over short or long term, to induce comparable embolism levels. Plants subjected to mild and prolonged water shortage (S) showed reduced growth, adjustment of turgor loss point driven by changes in both osmotic potential at full turgor and bulk modulus of elasticity, a lower content of soluble NSC and a higher content of starch with respect to control (C) plants. Moreover, S plants showed a lower ability to recover from xylem embolism than C plants, even after irrigation. Our data suggest that plant carbon status might indirectly influence plant performance during and after drought via effects on xylem hydraulic functioning, supporting the view of a possible mechanistic link between the two processes. Copyright © 2017 Elsevier Masson SAS. All rights reserved.

76 FR 40403 - R.E. Ginna Nuclear Power Plant, LLC, R.E. Ginna Nuclear Power Plant, R.E. Ginna Independent Spent...

Federal Register 2010, 2011, 2012, 2013, 2014

2011-07-08

... NUCLEAR REGULATORY COMMISSION [Docket No. 50-244; Docket No. 72-67] R.E. Ginna Nuclear Power Plant, LLC, R.E. Ginna Nuclear Power Plant, R.E. Ginna Independent Spent Fuel Storage Installation; Notice of... Facility Operating License No. DPR-18, for the R.E. Ginna Nuclear Power Plant (Ginna), currently held by R...

Mind the bubbles: achieving stable measurements of maximum hydraulic conductivity through woody plant samples

PubMed Central

Espino, Susana; Schenk, H. Jochen

2011-01-01

The maximum specific hydraulic conductivity (kmax) of a plant sample is a measure of the ability of a plants’ vascular system to transport water and dissolved nutrients under optimum conditions. Precise measurements of kmax are needed in comparative studies of hydraulic conductivity, as well as for measuring the formation and repair of xylem embolisms. Unstable measurements of kmax are a common problem when measuring woody plant samples and it is commonly observed that kmax declines from initially high values, especially when positive water pressure is used to flush out embolisms. This study was designed to test five hypotheses that could potentially explain declines in kmax under positive pressure: (i) non-steady-state flow; (ii) swelling of pectin hydrogels in inter-vessel pit membranes; (iii) nucleation and coalescence of bubbles at constrictions in the xylem; (iv) physiological wounding responses; and (v) passive wounding responses, such as clogging of the xylem by debris. Prehydrated woody stems from Laurus nobilis (Lauraceae) and Encelia farinosa (Asteraceae) collected from plants grown in the Fullerton Arboretum in Southern California, were used to test these hypotheses using a xylem embolism meter (XYL'EM). Treatments included simultaneous measurements of stem inflow and outflow, enzyme inhibitors, stem-debarking, low water temperatures, different water degassing techniques, and varied concentrations of calcium, potassium, magnesium, and copper salts in aqueous measurement solutions. Stable measurements of kmax were observed at concentrations of calcium, potassium, and magnesium salts high enough to suppress bubble coalescence, as well as with deionized water that was degassed using a membrane contactor under strong vacuum. Bubble formation and coalescence under positive pressure in the xylem therefore appear to be the main cause for declining kmax values. Our findings suggest that degassing of water is essential for achieving stable and precise

Competitiveness of biomass-fueled electrical power plants.

Treesearch

Bruce A. McCarl; Darius M. Adams; Ralph J. Alig; John T. Chmelik

2000-01-01

One way countries like the United States can comply with suggested rollbacks in greenhouse gas emissions is by employing power plants fueled with biomass. We examine the competitiveness of biomass-based fuel for electrical power as opposed to coal using a mathematical programming structure. We consider fueling power plants from milling residues, whole trees, logging...

Nuclear Power Plant Module, NPP-1: Nuclear Power Cost Analysis.

ERIC Educational Resources Information Center

Whitelaw, Robert L.

The purpose of the Nuclear Power Plant Modules, NPP-1, is to determine the total cost of electricity from a nuclear power plant in terms of all the components contributing to cost. The plan of analysis is in five parts: (1) general formulation of the cost equation; (2) capital cost and fixed charges thereon; (3) operational cost for labor,…

Hydraulic geometry of the Platte River in south-central Nebraska

USGS Publications Warehouse

Eschner, T.R.

1982-01-01

At-a-station hydraulic-geometry of the Platte River in south-central Nebraska is complex. The range of exponents of simple power-function relations is large, both between different reaches of the river, and among different sections within a given reach. The at-a-station exponents plot in several fields of the b-f-m diagram, suggesting that morphologic and hydraulic changes with increasing discharge vary considerably. Systematic changes in the plotting positions of the exponents with time indicate that in general, the width exponent has decreased, although trends are not readily apparent in the other exponents. Plots of the hydraulic-geometry relations indicate that simple power functions are not the proper model in all instances. For these sections, breaks in the slopes of the hydraulic geometry relations serve to partition the data sets. Power functions fit separately to the partitioned data described the width-, depth-, and velocity-discharge relations more accurately than did a single power function. Plotting positions of the exponents from hydraulic geometry relations of partitioned data sets on b-f-m diagrams indicate that much of the apparent variations of plotting positions of single power functions results because the single power functions compromise both subsets of partitioned data. For several sections, the shape of the channel primarily accounts for the better fit of two-power functions to partitioned data than a single power function over the entire range of data. These non-log linear relations may have significance for channel maintenance. (USGS)

Herb Hydraulics: Inter- and Intraspecific Variation in Three Ranunculus Species.

PubMed

Nolf, Markus; Rosani, Andrea; Ganthaler, Andrea; Beikircher, Barbara; Mayr, Stefan

2016-04-01

The requirements of the water transport system of small herbaceous species differ considerably from those of woody species. Despite their ecological importance for many biomes, knowledge regarding herb hydraulics remains very limited. We compared key hydraulic features (vulnerability to drought-induced hydraulic decline, pressure-volume relations, onset of cellular damage, in situ variation of water potential, and stomatal conductance) of three Ranunculus species differing in their soil humidity preferences and ecological amplitude. All species were very vulnerable to water stress (50% reduction in whole-leaf hydraulic conductance [kleaf] at -0.2 to -0.8 MPa). In species with narrow ecological amplitude, the drought-exposed Ranunculus bulbosus was less vulnerable to desiccation (analyzed via loss of kleaf and turgor loss point) than the humid-habitat Ranunculus lanuginosus Accordingly, water stress-exposed plants from the broad-amplitude Ranunculus acris revealed tendencies toward lower vulnerability to water stress (e.g. osmotic potential at full turgor, cell damage, and stomatal closure) than conspecific plants from the humid site. We show that small herbs can adjust to their habitat conditions on interspecific and intraspecific levels in various hydraulic parameters. The coordination of hydraulic thresholds (50% and 88% loss of kleaf, turgor loss point, and minimum in situ water potential) enabled the study species to avoid hydraulic failure and damage to living cells. Reversible recovery of hydraulic conductance, desiccation-tolerant seeds, or rhizomes may allow them to prioritize toward a more efficient but vulnerable water transport system while avoiding the severe effects that water stress poses on woody species. © 2016 American Society of Plant Biologists. All Rights Reserved.

Trade-offs between xylem hydraulic properties, wood anatomy and yield in Populus.

PubMed

Hajek, Peter; Leuschner, Christoph; Hertel, Dietrich; Delzon, Sylvain; Schuldt, Bernhard

2014-07-01

Trees face the dilemma that achieving high plant productivity is accompanied by a risk of drought-induced hydraulic failure due to a trade-off in the trees' vascular system between hydraulic efficiency and safety. By investigating the xylem anatomy of branches and coarse roots, and measuring branch axial hydraulic conductivity and vulnerability to cavitation in 4-year-old field-grown aspen plants of five demes (Populus tremula L. and Populus tremuloides Michx.) differing in growth rate, we tested the hypotheses that (i) demes differ in wood anatomical and hydraulic properties, (ii) hydraulic efficiency and safety are related to xylem anatomical traits, and (iii) aboveground productivity and hydraulic efficiency are negatively correlated to cavitation resistance. Significant deme differences existed in seven of the nine investigated branch-related anatomical and hydraulic traits but only in one of the four coarse-root-related anatomical traits; this likely is a consequence of high intra-plant variation in root morphology and the occurrence of a few 'high-conductivity roots'. Growth rate was positively related to branch hydraulic efficiency (xylem-specific conductivity) but not to cavitation resistance; this indicates that no marked trade-off exists between cavitation resistance and growth. Both branch hydraulic safety and hydraulic efficiency significantly depended on vessel size and were related to the genetic distance between the demes, while the xylem pressure causing 88% loss of hydraulic conductivity (P88 value) was more closely related to hydraulic efficiency than the commonly used P50 value. Deme-specific variation in the pit membrane structure may explain why vessel size was not directly linked to growth rate. We conclude that branch hydraulic efficiency is an important growth-influencing trait in aspen, while the assumed trade-off between productivity and hydraulic safety is weak. © The Author 2014. Published by Oxford University Press. All rights reserved

Root hydraulic vulnerability regulation of whole-plant conductance along hillslope gradients within subalpine and montane forests

NASA Astrophysics Data System (ADS)

Beverly, D.; Speckman, H. N.; Ewers, B. E.

2017-12-01

Ecosystem-scale models often rely on root vulnerability or whole-plant conductance for simulating seasonal evapotranspiration declines via constraints of water uptake and vegetation mortality. Further, many of these ecosystem models rely on single, unvarying, hydraulic parameter estimates for modeling large areas. Ring-porous species have shown seasonal variability in root vulnerability (percent loss of conductivity; PLC) and whole-plant conductance (Kw) but simulations of coniferous forest typically rely on point measurements. This assumption for coniferous forest is not likely true because of seasonal variability caused by phenology and environmental stresses and the potential for cavitation fatigue is not considered. Moreover, many of these dynamics have only been considered for stems even though roots are often the most vulnerable segments of the pathway for conifers. We hypothesized that seasonally dynamic whole-plant conductance along hillslope gradients in coniferous forests are regulated by cavitation fatigue within the roots resulting in seasonal increases in vulnerability. To test the hypothesis, a subalpine mixed forest (3000 m.a.s.l) and montane forest (2550 m.a.s.l.) were monitored between 2015-2017 to quantify PLC and Kw along the hillslope gradients of 300 m and 50 m, respectively. Forest plots were instrumented with 35 Granier-type sapflow sensors. Seasonal sampling campaigns occurred to quantify PLC through centrifuge techniques and Kw through Darcy's law approximations with pre-dawn and diurnal leaf water potentials. Downslope roots exhibit a 33% decrease in maximal conductivity corresponding to the approximately 50% decrease in whole-plant conductance suggesting seasonal soil dry-down limitations within the downslope stands. Upslope stands had no to little change in root vulnerability or decrease in whole-plant conductance as soil water limitations occur immediately following snowmelt, thus limiting hydraulic conductance throughout the growing

Gas exchange and hydraulics in seedlings of Hevea brasiliensis during water stress and recovery.

PubMed

Chen, Jun-Wen; Zhang, Qiang; Li, Xiao-Shuang; Cao, Kun-Fang

2010-07-01

The response of plants to drought has received significant attention, but far less attention has been given to the dynamic response of plants during recovery from drought. Photosynthetic performance and hydraulic capacity were monitored in seedlings of Hevea brasiliensis under water stress and during recovery following rewatering. Leaf water relation, gas exchange rate and hydraulic conductivity decreased gradually after water stress fell below a threshold, whereas instantaneous water use efficiency and osmolytes increased significantly. After 5 days of rewatering, leaf water relation, maximum stomatal conductance (g(s-max)) and plant hydraulic conductivity had recovered to the control levels except for sapwood area-specific hydraulic conductivity, photosynthetic assimilation rate and osmolytes. During the phase of water stress, stomata were almost completely closed before water transport efficiency decreased substantially, and moreover, the leaf hydraulic pathway was more vulnerable to water stress-induced embolism than the stem hydraulic pathway. Meanwhile, g(s-max) was linearly correlated with hydraulic capacity when water stress exceeded a threshold. In addition, a positive relationship was shown to occur between the recovery of g(s-max) and of hydraulic capacity during the phase of rewatering. Our results suggest (i) that stomatal closure effectively reduces the risk of xylem dysfunction in water-stressed plants at the cost of gas exchange, (ii) that the leaf functions as a safety valve to protect the hydraulic pathway from water stress-induced dysfunction to a larger extent than does the stem and (iii) that the full drought recovery of gas exchange is restricted by not only hydraulic factors but also non-hydraulic factors.

Ways to Improve Russian Coal-Fired Power Plants

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

Tumanovskii, A. G., E-mail: vti@vti.ru; Olkhovsky, G. G.

Coal is an important fuel for the electric power industry of Russia, especially in Ural and the eastern part of the country. It is fired in boilers of large (200 – 800 MW) condensing power units and in many cogeneration power plants with units rated at 50 – 180 MW. Many coal-fired power plants have been operated for more than 40 – 50 years. Though serviceable, their equipment is obsolete and does not comply with the current efficiency, environmental, staffing, and availability standards. It is urgent to retrofit and upgrade such power plants using advanced equipment, engineering and business ideas.more » Russian power-plant engineering companies have designed such advanced power units and their equipment such as boilers, turbines, auxiliaries, process and environmental control systems similar to those produced by the world’s leading manufacturers. Their performance and ways of implementation are discussed.« less

Predicting the hydraulic forces on submerged macrophytes from current velocity, biomass and morphology.

PubMed

Schutten, J; Davy, A J

2000-06-01

Aquatic macrophytes are important in stabilising moderately eutrophic, shallow freshwater lakes in the clear-water state. The failure of macrophyte recovery in lakes with very soft, highly organic sediments that have been restored to clear water by biomanipulation (e.g. in the Norfolk Broads, UK) has suggested that the physical stability of the sediment may limit plant establishment. Hydraulic forces from water currents may be sufficient to break or remove plants. Our aim was to develop a simple model that could predict these forces from plant biomass, current velocity and plant form. We used an experimental flume to measure the hydraulic forces acting on shoots of 18 species of aquatic macrophyte of varying size and morphology. The hydraulic drag on the shoots was regressed on a theoretically derived predictor (shoot biomass × current velocity 1.5 ). Such linear regressions proved to be highly significant for most species. The slopes of these lines represent species-specific, hydraulic roughness factors that are analogous to classical drag coefficients. Shoot architecture parameters describing leaf and shoot shape had significant effects on the hydraulic roughness factor. Leaf width and shoot stiffness individually did not have a significant influence, but in combination with shoot shape they were significant. This hydraulic model was validated for a subset of species using measurements from an independent set of shoots. When measured and predicted hydraulic forces were compared, the fit was generally very good, except for two species with morphological variations. This simple model, together with the plant-specific factors, provides a basis for predicting the hydraulic forces acting on the root systems of macrophytes under field conditions. This information should allow prediction of the physical stability of individual plants, as an aid to shallow-lake management.

75 FR 9958 - Carolina Power & Light Company, Shearon Harris Nuclear Power Plant, Unit 1; Exemption

Federal Register 2010, 2011, 2012, 2013, 2014

2010-03-04

..., Shearon Harris Nuclear Power Plant, Unit 1; Exemption 1.0 Background Carolina Power & Light Company (the... Operating License No. NPF-63, which authorizes operation of the Shearon Harris Nuclear Power Plant, Unit 1... rule's compliance date for all operating nuclear power plants, but noted that the Commission's...

Hydraulics of sub-superficial flow constructed wetlands in semi arid climate conditions.

PubMed

Ranieri, E

2003-01-01

This paper reports the evaluation of the hydraulics of two constructed wetland (cw(s)) plants located in Apulia (the South Eastern Italy region characterized by semi arid climate conditions). These fields were planted with Phragmites australis hydrophytes and are supplied with local secondary wastewater municipal treatment plant effluent. Each plant--Kickuth Root-Zone method based--covers an area of approx. 2,000 m2. The evapotranspiration phenomenon has been evaluated within perforated tubes fixed to the field bottom and very high values--up to 40 mm/d--were found. Hydraulic conductivity has been evaluated by in situ measurements at different field points. Hydraulic gradients and the piezometric curve within the field are also reported.

Leaf maximum photosynthetic rate and venation are linked by hydraulics.

PubMed

Brodribb, Tim J; Feild, Taylor S; Jordan, Gregory J

2007-08-01

Leaf veins are almost ubiquitous across the range of terrestrial plant diversity, yet their influence on leaf photosynthetic performance remains uncertain. We show here that specific physical attributes of the vascular plumbing network are key limiters of the hydraulic and photosynthetic proficiency of any leaf. Following the logic that leaf veins evolved to bypass inefficient water transport through living mesophyll tissue, we examined the hydraulic pathway beyond the distal ends of the vein system as a possible limiter of water transport in leaves. We tested a mechanistic hypothesis that the length of this final traverse, as water moves from veins across the mesophyll to where it evaporates from the leaf, governs the hydraulic efficiency and photosynthetic carbon assimilation of any leaf. Sampling 43 species across the breadth of plant diversity from mosses to flowering plants, we found that the post-vein traverse as determined by characters such as vein density, leaf thickness, and cell shape, was strongly correlated with the hydraulic conductivity and maximum photosynthetic rate of foliage. The shape of this correlation provided clear support for the a priori hypothesis that vein positioning limits photosynthesis via its influence on leaf hydraulic efficiency.

75 FR 3942 - Carolina Power & Light Company Shearon Harris Nuclear Power Plant, Unit 1 Environmental...

Federal Register 2010, 2011, 2012, 2013, 2014

2010-01-25

... Shearon Harris Nuclear Power Plant, Unit 1 Environmental Assessment and Finding of No Significant Impact... Nuclear Power Plant, Unit 1 (HNP), located in New Hill, North Carolina. In accordance with 10 CFR 51.21... of Nuclear Plants: Regarding Shearon Harris Nuclear Power Plant, Unit 1--Final Report (NUREG-1437...

Magnetic fusion commercial power plants

NASA Astrophysics Data System (ADS)

Sheffield, J.

Toroidal magnetic systems present the best opportunity to make a commercial fusion power plant. They offer potential solutions to the main requirements that confront a power plant designer. An ideal system may be postulated in which the coils are a very small part of the cost, and the cost stems primarily from the inescapable components: minimal plasma heating (and sustaining system), tritium breeding blanket, shield, particle input, removal and treatment system, heat transfer system, generators, buildings, and balance of plant. No present system meets the ideal standards; however, toroidal systems contain among them the elements required. Consequently, a logical program may be based upon an evolutionary development, building on the contributions of the tokamak, which has been the mainline of research for a number of years.

A parametric simulation of solar chimney power plant

NASA Astrophysics Data System (ADS)

Beng Hooi, Lim; Kannan Thangavelu, Saravana

2018-01-01

The strong solar radiation, continuous supplies of sunlight and environmental friendly factors have made the solar chimney power plant becoming highly feasible to build in Malaysia. Solar chimney power plant produces upward buoyancy force through the greenhouse effect. Numerical simulation was performed on the model of a solar chimney power plant using the ANSYS Fluent software by applying standard k-epsilon turbulence model and discrete ordinates (DO) radiation model to solve the relevant equations. A parametric study was carried out to evaluate the performance of solar chimney power plant, which focused on the temperature rise in the collector, air velocity at the chimney base, and pressure drop inside the chimney were based on the results of temperature, velocity, and static pressure distributions. The results demonstrate reliability by comparing a model with the experimental data of Manzanares Spanish prototype. Based on the numerical results, power capacity and efficiency were analysed theoretically. Results indicate that a stronger solar radiation and larger prototype will improve the performance of solar chimney power plant.

Power function decay of hydraulic conductivity for a TOPMODEL-based infiltration routine

NASA Astrophysics Data System (ADS)

Wang, Jun; Endreny, Theodore A.; Hassett, James M.

2006-11-01

TOPMODEL rainfall-runoff hydrologic concepts are based on soil saturation processes, where soil controls on hydrograph recession have been represented by linear, exponential, and power function decay with soil depth. Although these decay formulations have been incorporated into baseflow decay and topographic index computations, only the linear and exponential forms have been incorporated into infiltration subroutines. This study develops a power function formulation of the Green and Ampt infiltration equation for the case where the power n = 1 and 2. This new function was created to represent field measurements in the New York City, USA, Ward Pound Ridge drinking water supply area, and provide support for similar sites reported by other researchers. Derivation of the power-function-based Green and Ampt model begins with the Green and Ampt formulation used by Beven in deriving an exponential decay model. Differences between the linear, exponential, and power function infiltration scenarios are sensitive to the relative difference between rainfall rates and hydraulic conductivity. Using a low-frequency 30 min design storm with 4.8 cm h-1 rain, the n = 2 power function formulation allows for a faster decay of infiltration and more rapid generation of runoff. Infiltration excess runoff is rare in most forested watersheds, and advantages of the power function infiltration routine may primarily include replication of field-observed processes in urbanized areas and numerical consistency with power function decay of baseflow and topographic index distributions. Equation development is presented within a TOPMODEL-based Ward Pound Ridge rainfall-runoff simulation. Copyright

78 FR 55118 - Seismic Instrumentation for Nuclear Power Plants

Federal Register 2010, 2011, 2012, 2013, 2014

2013-09-09

... NUCLEAR REGULATORY COMMISSION [NRC-2013-0202] Seismic Instrumentation for Nuclear Power Plants... Reports for Nuclear Power Plants: LWR Edition,'' Section 3.7.4, ``Seismic Instrumentation.'' DATES: Submit... Nuclear Power Plants: LWR Edition'' (SRP, from the current Revision 2 to a new Revision 3). The proposed...

Preliminary assessment of alternative PFBC power plant systems. Final report

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

Wysocki, J.; Rogali, R.

1980-07-01

This report presents the design and and economic comparisons of the following nominal 1000 MWe PFBC power plants for both eastern and western coal: Curtiss-Wright PFBC power plants with an air-cooled design; General Electric RFBC power plants with a steam-cooled design; and AEP/Stal-Laval PFBC power plants with a steam-cooled design. In addition, reference pulverized coal-fired (PCF) power plants are included for comparison purposes. The results of the analysis indicate: (1) The steam-cooled PFBC designs show potential savings of 10% and 11% over PCF plants for eastern and western coal, respectively, in terms of busbar power cost; (2) the air-cooled PFBCmore » designs show potential savings of 1% and 2% over PCF plants for eastern and western coal, respectively, in terms of busbar power cost.« less

Degradation of phosphate ester hydraulic fluid in power station turbines investigated by a three-magnet unilateral magnet array.

PubMed

Guo, Pan; He, Wei; García-Naranjo, Juan C

2014-04-14

A three-magnet array unilateral NMR sensor with a homogeneous sensitive spot was employed for assessing aging of the turbine oils used in two different power stations. The Carr-Purcell-Meiboom-Gill (CPMG) sequence and Inversion Recovery-prepared CPMG were employed for measuring the ¹H-NMR transverse and longitudinal relaxation times of turbine oils with different service status. Two signal components with different lifetimes were obtained by processing the transverse relaxation curves with a numeric program based on the Inverse Laplace Transformation. The long lifetime components of the transverse relaxation time T₂eff and longitudinal relaxation time T₁ were chosen to monitor the hydraulic fluid aging. The results demonstrate that an increase of the service time of the turbine oils clearly results in a decrease of T₂eff,long and T₁,long. This indicates that the T₂eff,long and T₁,long relaxation times, obtained from the unilateral magnetic resonance measurements, can be applied as indices for degradation of the hydraulic fluid in power station turbines.

Simulation model of a variable-speed pumped-storage power plant in unstable operating conditions in pumping mode

NASA Astrophysics Data System (ADS)

Martínez-Lucas, G.; Pérez-Díaz, J. I.; Sarasúa, J. I.; Cavazzini, G.; Pavesi, G.; Ardizzon, G.

2017-04-01

This paper presents a dynamic simulation model of a laboratory-scale pumped-storage power plant (PSPP) operating in pumping mode with variable speed. The model considers the dynamic behavior of the conduits by means of an elastic water column approach, and synthetically generates both pressure and torque pulsations that reproduce the operation of the hydraulic machine in its instability region. The pressure and torque pulsations are generated each from a different set of sinusoidal functions. These functions were calibrated from the results of a CFD model, which was in turn validated from experimental data. Simulation model results match the numerical results of the CFD model with reasonable accuracy. The pump-turbine model (the functions used to generate pressure and torque pulsations inclusive) was up-scaled by hydraulic similarity according to the design parameters of a real PSPP and included in a dynamic simulation model of the said PSPP. Preliminary conclusions on the impact of unstable operation conditions on the penstock fatigue were obtained by means of a Monte Carlo simulation-based fatigue analysis.

Stillwater Hybrid Geo-Solar Power Plant Optimization Analyses

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

Wendt, Daniel S.; Mines, Gregory L.; Turchi, Craig S.

2015-09-02

The Stillwater Power Plant is the first hybrid plant in the world able to bring together a medium-enthalpy geothermal unit with solar thermal and solar photovoltaic systems. Solar field and power plant models have been developed to predict the performance of the Stillwater geothermal / solar-thermal hybrid power plant. The models have been validated using operational data from the Stillwater plant. A preliminary effort to optimize performance of the Stillwater hybrid plant using optical characterization of the solar field has been completed. The Stillwater solar field optical characterization involved measurement of mirror reflectance, mirror slope error, and receiver position error.more » The measurements indicate that the solar field may generate 9% less energy than the design value if an appropriate tracking offset is not employed. A perfect tracking offset algorithm may be able to boost the solar field performance by about 15%. The validated Stillwater hybrid plant models were used to evaluate hybrid plant operating strategies including turbine IGV position optimization, ACC fan speed and turbine IGV position optimization, turbine inlet entropy control using optimization of multiple process variables, and mixed working fluid substitution. The hybrid plant models predict that each of these operating strategies could increase net power generation relative to the baseline Stillwater hybrid plant operations.« less

Hydraulic integration and shrub growth form linked across continental aridity gradients.

Treesearch

H. Jochen Schenk; Susana Espino; Christine M. Goedhart; Marisa Nordenstahl; Hugo I. Martinez Cabrera; Cynthia S. Jones

2009-01-01

Both engineered hydraulic systems and plant hydraulic systems are protected against failure by resistance, reparability, and redundancy. A basic rule of reliability engineering is that the level of...

Hydraulic analysis and optimization design in Guri rehabilitation project

NASA Astrophysics Data System (ADS)

Cheng, H.; Zhou, L. J.; Gong, L.; Wang, Z. N.; Wen, Q.; Zhao, Y. Z.; Wang, Y. L.

2016-11-01

Recently Dongfang was awarded the contract for rehabilitation of 6 units in Guri power plant, the biggest hydro power project in Venezuela. The rehabilitation includes, but not limited to, the extension of output capacity by about 50% and enhancement of efficiency level. To achieve the targets the runner and the guide vanes will be replaced by the newly optimized designs. In addition, the out-of-date stay vanes with straight plate shape will be modified into proper profiles after considering the application feasibility in field. The runner and vane profiles were optimized by using state-of-the-art flow simulation techniques. And the hydraulic performances were confirmed by the following model tests. This paper describes the flow analysis during the optimization procedure and the comparison between various technical concepts.

Facing technological challenges of Solar Updraft Power Plants

NASA Astrophysics Data System (ADS)

Lupi, F.; Borri, C.; Harte, R.; Krätzig, W. B.; Niemann, H.-J.

2015-01-01

The Solar Updraft Power Plant technology addresses a very challenging idea of combining two kinds of renewable energy: wind and solar. The working principle is simple: a Solar Updraft Power Plant (SUPP) consists of a collector area to heat the air due to the wide-banded ultra-violet solar radiation, the high-rise solar tower to updraft the heated air to the atmosphere, and in between the power conversion unit, where a system of coupled turbines and generators transforms the stream of heated air into electric power. A good efficiency of the power plant can only be reached with extra-large dimensions of the tower and/or the collector area. The paper presents an up-to-date review of the SUPP technology, focusing on the multi-physics modeling of the power plant, on the structural behavior of the tower and, last but not least, on the modeling of the stochastic wind loading process.

Operate a Nuclear Power Plant.

ERIC Educational Resources Information Center

Frimpter, Bonnie J.; And Others

1983-01-01

Describes classroom use of a computer program originally published in Creative Computing magazine. "The Nuclear Power Plant" (runs on Apple II with 48K memory) simulates the operating of a nuclear generating station, requiring students to make decisions as they assume the task of managing the plant. (JN)

46 CFR 112.50-3 - Hydraulic starting.

Code of Federal Regulations, 2010 CFR

2010-10-01

... 46 Shipping 4 2010-10-01 2010-10-01 false Hydraulic starting. 112.50-3 Section 112.50-3 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) ELECTRICAL ENGINEERING EMERGENCY LIGHTING AND POWER SYSTEMS Emergency Diesel and Gas Turbine Engine Driven Generator Sets § 112.50-3 Hydraulic...

46 CFR 112.50-3 - Hydraulic starting.

Code of Federal Regulations, 2011 CFR

2011-10-01

... 46 Shipping 4 2011-10-01 2011-10-01 false Hydraulic starting. 112.50-3 Section 112.50-3 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) ELECTRICAL ENGINEERING EMERGENCY LIGHTING AND POWER SYSTEMS Emergency Diesel and Gas Turbine Engine Driven Generator Sets § 112.50-3 Hydraulic...

Combined compressed air storage-low BTU coal gasification power plant

DOEpatents

Kartsounes, George T.; Sather, Norman F.

1979-01-01

An electrical generating power plant includes a Compressed Air Energy Storage System (CAES) fueled with low BTU coal gas generated in a continuously operating high pressure coal gasifier system. This system is used in coordination with a continuously operating main power generating plant to store excess power generated during off-peak hours from the power generating plant, and to return the stored energy as peak power to the power generating plant when needed. The excess coal gas which is produced by the coal gasifier during off-peak hours is stored in a coal gas reservoir. During peak hours the stored coal gas is combined with the output of the coal gasifier to fuel the gas turbines and ultimately supply electrical power to the base power plant.

Promoting water hydraulics in Malaysia: A green educational approach

NASA Astrophysics Data System (ADS)

Yusof, Ahmad Anas; Zaili, Zarin Syukri; Hassan, Siti Nor Habibah; Tuan, Tee Boon; Saadun, Mohd Noor Asril; Ibrahim, Mohd Qadafie

2014-10-01

In promoting water hydraulics in Malaysia, this paper presents research development of water hydraulics educational training system for secondary and tertiary levels in Malaysia. Water hydraulics trainer with robotic attachment has been studied in order to promote the usefulness of such educational tools in promoting sustainability and green technology in the country. The trainer is being developed in order to allow constructive curriculum development and continuous marketing research for the effectiveness and usefulness of using water in hydraulic power trainer. The research on water-based hydraulic trainer is now possible with the current development in water hydraulics technology.

Nuclear Power Plants | RadTown USA | US EPA

EPA Pesticide Factsheets

2018-06-22

Nuclear power plants produce electricity from the heat created by splitting uranium atoms. In the event of a nuclear power plant emergency, follow instructions from emergency responders and public officials.

Power plant fault detection using artificial neural network

NASA Astrophysics Data System (ADS)

Thanakodi, Suresh; Nazar, Nazatul Shiema Moh; Joini, Nur Fazriana; Hidzir, Hidzrin Dayana Mohd; Awira, Mohammad Zulfikar Khairul

2018-02-01

The fault that commonly occurs in power plants is due to various factors that affect the system outage. There are many types of faults in power plants such as single line to ground fault, double line to ground fault, and line to line fault. The primary aim of this paper is to diagnose the fault in 14 buses power plants by using an Artificial Neural Network (ANN). The Multilayered Perceptron Network (MLP) that detection trained utilized the offline training methods such as Gradient Descent Backpropagation (GDBP), Levenberg-Marquardt (LM), and Bayesian Regularization (BR). The best method is used to build the Graphical User Interface (GUI). The modelling of 14 buses power plant, network training, and GUI used the MATLAB software.

Energy saving and consumption reducing evaluation of thermal power plant

NASA Astrophysics Data System (ADS)

Tan, Xiu; Han, Miaomiao

2018-03-01

At present, energy saving and consumption reduction require energy saving and consumption reduction measures for thermal power plant, establishing an evaluation system for energy conservation and consumption reduction is instructive for the whole energy saving work of thermal power plant. By analysing the existing evaluation system of energy conservation and consumption reduction, this paper points out that in addition to the technical indicators of power plant, market activities should also be introduced in the evaluation of energy saving and consumption reduction in power plant. Ttherefore, a new evaluation index of energy saving and consumption reduction is set up and the example power plant is calculated in this paper. Rresults show that after introducing the new evaluation index of energy saving and consumption reduction, the energy saving effect of the power plant can be judged more comprehensively, so as to better guide the work of energy saving and consumption reduction in power plant.

MIDDLE GORGE POWER PLANT, OWENS RIVER STREAM FLOWING OVER TAIL ...

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

MIDDLE GORGE POWER PLANT, OWENS RIVER STREAM FLOWING OVER TAIL RACE OF POWER PLANT AND PENSTOCK HEADGATE TO LOWER GORGE CONTROL PLANT. A MINIMAL FLOW OF RIVER WATER IS REQUIRED TO MAINTAIN FISH LIFE - Los Angeles Aqueduct, Middle Gorge Power Plant, Los Angeles, Los Angeles County, CA

Governor stability simulations of Svartisen power plant verified by the installed monitoring system on site

NASA Astrophysics Data System (ADS)

Nielsen, T. K.; Kjeldsen, M.

2010-08-01

Many Norwegian hydro power plants have complex lay-out with several reservoirs, broke intakes, surge shafts and even air cushion chambers. There are kilometers of excavated tunnels as well as long tail water systems. The stations are often equipped by multiple of turbines, both in series and parallel. A number of operation modes are therefore possible. Doing transient simulations and simulations of governor stability in the design phase, the problem is to find the worst case scenario regarding these operating modes. Svartisen power plant has been of particular interest these days. The power plant is originally designed for two 350 MW Francis turbines, however, only one turbine was installed. When designed, governor stability was regarded as problematic due to the long penstock. A long penstock will give a too high time constant for the hydraulic inertia. The main problem here is, however, the water hammer frequency that interferes with the governor performance. The frequency is in the same range as the cross frequency. Therefore the governor will react on these water hammer waves, which in its nature is notoriously unstable. The common solution is to build an air cushion and thereby increase the water hammer frequency above the cross frequency. The expenses were, however, deemed too high, and it was necessary to seek for other solutions. A pressure feedback on the governor was introduced in order to have stable operation at least for two turbines. With only one turbine installed, the pressure feedback has not been activated because, based on the simulations, it was regarded unnecessary. Even if the original simulations shows good stability margins when only one turbine is running, there has been some indications that the aggregate has suffered from instability. In 2004 Svartisen Power Plant was equipped with a comprehensive monitoring system. Both the turbine and the generator performance have been observed. This gives valuable information on how the hydropower

Layouts of trigeneration plants for centralized power supply

NASA Astrophysics Data System (ADS)

Klimenko, A. V.; Agababov, V. S.; Il'ina, I. P.; Rozhnatovskii, V. D.; Burmakina, A. V.

2016-06-01

One of the possible and, under certain conditions, sufficiently effective methods for reducing consumption of fuel and energy resources is the development of plants for combined generation of different kinds of energy. In the power industry of Russia, the facilities have become widespread in which the cogeneration technology, i.e., simultaneous generation of electric energy and heat, is implemented. Such facilities can use different plants, viz., gas- and steam-turbine plants and gas-reciprocating units. Cogeneration power supply can be further developed by simultaneously supplying the users not only with electricity and heat but also with cold. Such a technology is referred to as trigeneration. To produce electricity and heat, trigeneration plants can use the same facilities that are used in cogeneration, namely, gas-turbine plants, steam-turbine plants, and gas-reciprocating units. Cold can be produced in trigeneration plants using thermotransformers of various kinds, such as vaporcompression thermotransformers, air thermotransformers, and absorption thermotransformers, that operate as chilling machines. The thermotransformers can also be used in the trigeneration plants to generate heat. The main advantage of trigeneration plants based on gas-turbine plants or gas-reciprocating units over cogeneration plants is the increased thermodynamic power supply efficiency owing to utilization of the waste-gas heat not only in winter but also in summer. In the steam-turbine-based trigeneration plants equipped with absorption thermotransformers, the enhancement of the thermodynamic power supply efficiency is determined by the increase in the heat extraction load during the nonheating season. The article presents calculated results that demonstrate higher thermodynamic efficiency of a gas-turbine-based plant with an absorption thermotransformer that operates in the trigeneration mode compared with a cogeneration gas-turbine plant. The structural arrangements of trigeneration

75 FR 80547 - Carolina Power & Light Company, Shearon Harris Nuclear Power Plant, Unit No. 1; Exemption

Federal Register 2010, 2011, 2012, 2013, 2014

2010-12-22

..., Shearon Harris Nuclear Power Plant, Unit No. 1; Exemption 1.0 Background Carolina Power & Light Company... operation of the Shearon Harris Nuclear Power Plant (HNP), Unit 1. The license provides, among other things... request to generically extend the rule's compliance date for all operating nuclear power plants, but noted...

Safety Regulation of Nuclear Power Plant License Renewal

NASA Astrophysics Data System (ADS)

Zhang, Qiaoe; Liu, Ting; Qi, Yuan; Yang, LiLi

2018-01-01

China’s regulations stipulate that a nuclear power plant license is valid for a design life period (generally 30 or 40 years). Whether the nuclear power plant’s license is renewed after the expiration of the license is to be determined based on the safety and economy of the nuclear power plant..

10. Floor Layout of Thermal Hydraulics Laboratory, from The Thermal ...

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

10. Floor Layout of Thermal Hydraulics Laboratory, from The Thermal Hydraulics Laboratory at Hanford. General Electric Company, Hanford Atomic Products Operation, Richland, Washington, 1961. - D-Reactor Complex, Deaeration Plant-Refrigeration Buildings, Area 100-D, Richland, Benton County, WA

Linking hydraulic traits to tropical forest function in a size-structured and trait-driven model (TFS v.1-Hydro)

NASA Astrophysics Data System (ADS)

Christoffersen, Bradley O.; Gloor, Manuel; Fauset, Sophie; Fyllas, Nikolaos M.; Galbraith, David R.; Baker, Timothy R.; Kruijt, Bart; Rowland, Lucy; Fisher, Rosie A.; Binks, Oliver J.; Sevanto, Sanna; Xu, Chonggang; Jansen, Steven; Choat, Brendan; Mencuccini, Maurizio; McDowell, Nate G.; Meir, Patrick

2016-11-01

Forest ecosystem models based on heuristic water stress functions poorly predict tropical forest response to drought partly because they do not capture the diversity of hydraulic traits (including variation in tree size) observed in tropical forests. We developed a continuous porous media approach to modeling plant hydraulics in which all parameters of the constitutive equations are biologically interpretable and measurable plant hydraulic traits (e.g., turgor loss point πtlp, bulk elastic modulus ɛ, hydraulic capacitance Cft, xylem hydraulic conductivity ks,max, water potential at 50 % loss of conductivity for both xylem (P50,x) and stomata (P50,gs), and the leaf : sapwood area ratio Al : As). We embedded this plant hydraulics model within a trait forest simulator (TFS) that models light environments of individual trees and their upper boundary conditions (transpiration), as well as providing a means for parameterizing variation in hydraulic traits among individuals. We synthesized literature and existing databases to parameterize all hydraulic traits as a function of stem and leaf traits, including wood density (WD), leaf mass per area (LMA), and photosynthetic capacity (Amax), and evaluated the coupled model (called TFS v.1-Hydro) predictions, against observed diurnal and seasonal variability in stem and leaf water potential as well as stand-scaled sap flux. Our hydraulic trait synthesis revealed coordination among leaf and xylem hydraulic traits and statistically significant relationships of most hydraulic traits with more easily measured plant traits. Using the most informative empirical trait-trait relationships derived from this synthesis, TFS v.1-Hydro successfully captured individual variation in leaf and stem water potential due to increasing tree size and light environment, with model representation of hydraulic architecture and plant traits exerting primary and secondary controls, respectively, on the fidelity of model predictions. The plant

Linking hydraulic traits to tropical forest function in a size-structured and trait-driven model (TFS v.1-Hydro)

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

Christoffersen, Bradley O.; Gloor, Manuel; Fauset, Sophie

Forest ecosystem models based on heuristic water stress functions poorly predict tropical forest response to drought partly because they do not capture the diversity of hydraulic traits (including variation in tree size) observed in tropical forests. We developed a continuous porous media approach to modeling plant hydraulics in which all parameters of the constitutive equations are biologically interpretable and measurable plant hydraulic traits (e.g., turgor loss point π tlp, bulk elastic modulus ε, hydraulic capacitance C ft, xylem hydraulic conductivity k s,max, water potential at 50 % loss of conductivity for both xylem ( P 50,x) and stomata ( Pmore » 50,gs), and the leaf : sapwood area ratio A l: A s). We embedded this plant hydraulics model within a trait forest simulator (TFS) that models light environments of individual trees and their upper boundary conditions (transpiration), as well as providing a means for parameterizing variation in hydraulic traits among individuals. We synthesized literature and existing databases to parameterize all hydraulic traits as a function of stem and leaf traits, including wood density (WD), leaf mass per area (LMA), and photosynthetic capacity ( A max ), and evaluated the coupled model (called TFS v.1-Hydro) predictions, against observed diurnal and seasonal variability in stem and leaf water potential as well as stand-scaled sap flux. Our hydraulic trait synthesis revealed coordination among leaf and xylem hydraulic traits and statistically significant relationships of most hydraulic traits with more easily measured plant traits. Using the most informative empirical trait–trait relationships derived from this synthesis, TFS v.1-Hydro successfully captured individual variation in leaf and stem water potential due to increasing tree size and light environment, with model representation of hydraulic architecture and plant traits exerting primary and secondary controls, respectively, on the fidelity of model

Linking hydraulic traits to tropical forest function in a size-structured and trait-driven model (TFS v.1-Hydro)

DOE PAGES

Christoffersen, Bradley O.; Gloor, Manuel; Fauset, Sophie; ...

2016-11-24

Forest ecosystem models based on heuristic water stress functions poorly predict tropical forest response to drought partly because they do not capture the diversity of hydraulic traits (including variation in tree size) observed in tropical forests. We developed a continuous porous media approach to modeling plant hydraulics in which all parameters of the constitutive equations are biologically interpretable and measurable plant hydraulic traits (e.g., turgor loss point π tlp, bulk elastic modulus ε, hydraulic capacitance C ft, xylem hydraulic conductivity k s,max, water potential at 50 % loss of conductivity for both xylem ( P 50,x) and stomata ( Pmore » 50,gs), and the leaf : sapwood area ratio A l: A s). We embedded this plant hydraulics model within a trait forest simulator (TFS) that models light environments of individual trees and their upper boundary conditions (transpiration), as well as providing a means for parameterizing variation in hydraulic traits among individuals. We synthesized literature and existing databases to parameterize all hydraulic traits as a function of stem and leaf traits, including wood density (WD), leaf mass per area (LMA), and photosynthetic capacity ( A max ), and evaluated the coupled model (called TFS v.1-Hydro) predictions, against observed diurnal and seasonal variability in stem and leaf water potential as well as stand-scaled sap flux. Our hydraulic trait synthesis revealed coordination among leaf and xylem hydraulic traits and statistically significant relationships of most hydraulic traits with more easily measured plant traits. Using the most informative empirical trait–trait relationships derived from this synthesis, TFS v.1-Hydro successfully captured individual variation in leaf and stem water potential due to increasing tree size and light environment, with model representation of hydraulic architecture and plant traits exerting primary and secondary controls, respectively, on the fidelity of model

14. Power copy of drawing, August 21, 1915. POWER PLANT ...

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

14. Power copy of drawing, August 21, 1915. POWER PLANT EXTENSION, GENERAL PLANS. Drawing No. 4415, Facilities Engineering, Army Materials Technology Laboratory, Watertown, Massachusetts. - Watertown Arsenal, Building No. 60, Arsenal Street, Watertown, Middlesex County, MA

Physical and hydraulic properties of baked ceramic aggregates used for plant growth medium

NASA Technical Reports Server (NTRS)

Steinberg, Susan L.; Kluitenberg, Gerard J.; Jones, Scott B.; Daidzic, Nihad E.; Reddi, Lakshmi N.; Xiao, Ming; Tuller, Markus; Newman, Rebecca M.; Or, Dani; Alexander, J. Iwan. D.

2005-01-01

Baked ceramic aggregates (fritted clay, arcillite) have been used for plant research both on the ground and in microgravity. Optimal control of water and air within the root zone in any gravity environment depends on physical and hydraulic properties of the aggregate, which were evaluated for 0.25-1-mm and 1-2-mm particle size distributions. The maximum bulk densities obtained by any packing technique were 0.68 and 0.64 g cm-3 for 0.25-1-mm and 1-2-mm particles, respectively. Wettable porosity obtained by infiltration with water was approximately 65%, substantially lower than total porosity of approximately 74%. Aggregate of both particle sizes exhibited a bimodal pore size distribution consisting of inter-aggregate macropores and intra-aggregate micropores, with the transition from macro- to microporosity beginning at volumetric water content of approximately 36% to 39%. For inter-aggregate water contents that support optimal plant growth there is 45% change in water content that occurs over a relatively small matric suction range of 0-20 cm H2O for 0.25-1-mm and 0 to -10 cm H2O for 1-2-mm aggregate. Hysteresis is substantial between draining and wetting aggregate, which results in as much as a approximately 10% to 20% difference in volumetric water content for a given matric potential. Hydraulic conductivity was approximately an order of magnitude higher for 1-2-mm than for 0.25-1-mm aggregate until significant drainage of the inter-aggregate pore space occurred. The large change in water content for a relatively small change in matric potential suggests that significant differences in water retention may be observed in microgravity as compared to earth.

Inertial Fusion Power Plant Concept of Operations and Maintenance

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

Anklam, T.; Knutson, B.; Dunne, A. M.

2015-01-15

Parsons and LLNL scientists and engineers performed design and engineering work for power plant pre-conceptual designs based on the anticipated laser fusion demonstrations at the National Ignition Facility (NIF). Work included identifying concepts of operations and maintenance (O&M) and associated requirements relevant to fusion power plant systems analysis. A laser fusion power plant would incorporate a large process and power conversion facility with a laser system and fusion engine serving as the heat source, based in part on some of the systems and technologies advanced at NIF. Process operations would be similar in scope to those used in chemical, oilmore » refinery, and nuclear waste processing facilities, while power conversion operations would be similar to those used in commercial thermal power plants. While some aspects of the tritium fuel cycle can be based on existing technologies, many aspects of a laser fusion power plant presents several important and unique O&M requirements that demand new solutions. For example, onsite recovery of tritium; unique remote material handling systems for use in areas with high radiation, radioactive materials, or high temperatures; a five-year fusion engine target chamber replacement cycle with other annual and multi-year cycles anticipated for major maintenance of other systems, structures, and components (SSC); and unique SSC for fusion target waste recycling streams. This paper describes fusion power plant O&M concepts and requirements, how O&M requirements could be met in design, and how basic organizational and planning issues can be addressed for a safe, reliable, economic, and feasible fusion power plant.« less

Inertial fusion power plant concept of operations and maintenance

NASA Astrophysics Data System (ADS)

Knutson, Brad; Dunne, Mike; Kasper, Jack; Sheehan, Timothy; Lang, Dwight; Anklam, Tom; Roberts, Valerie; Mau, Derek

2015-02-01

Parsons and LLNL scientists and engineers performed design and engineering work for power plant pre-conceptual designs based on the anticipated laser fusion demonstrations at the National Ignition Facility (NIF). Work included identifying concepts of operations and maintenance (O&M) and associated requirements relevant to fusion power plant systems analysis. A laser fusion power plant would incorporate a large process and power conversion facility with a laser system and fusion engine serving as the heat source, based in part on some of the systems and technologies advanced at NIF. Process operations would be similar in scope to those used in chemical, oil refinery, and nuclear waste processing facilities, while power conversion operations would be similar to those used in commercial thermal power plants. While some aspects of the tritium fuel cycle can be based on existing technologies, many aspects of a laser fusion power plant presents several important and unique O&M requirements that demand new solutions. For example, onsite recovery of tritium; unique remote material handling systems for use in areas with high radiation, radioactive materials, or high temperatures; a five-year fusion engine target chamber replacement cycle with other annual and multi-year cycles anticipated for major maintenance of other systems, structures, and components (SSC); and unique SSC for fusion target waste recycling streams. This paper describes fusion power plant O&M concepts and requirements, how O&M requirements could be met in design, and how basic organizational and planning issues can be addressed for a safe, reliable, economic, and feasible fusion power plant.

Leasing of Nuclear Power Plants With Using Floating Technologies

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

Kuznetsov, Yu.N.; Gabaraev, B.A.; Reshetov, V.A.

2002-07-01

The proposal to organize and realize the international program on leasing of Nuclear Power Plant (NPP) reactor compartments is brought to the notice of potential partners. The proposal is oriented to the construction of new NPPs or to replacement of worked-out reactor units of the NPPs in operation on the sites situated near water area and to the use of afloat technologies for construction, mounting and transportation of reactor units as a Reactor Compartment Block Module (RCBM). According to the offered project the RCBM is fabricated in factory conditions at the largest Russian defense shipbuilding plant - State Unitary Enterprisemore » 'Industrial Association SEVMASHPREDPRIYATIE' (SEVMASH) in the city of Severodvinsk of the Arkhangelsk region. After completion of assembling, testing and preliminary licensing the RCBM is given buoyancy by means of hermetic sealing and using pontoons and barges. The RCBM delivery to the NPP site situated near water area is performed by sea route. The RCBM is brought to the place of its installation with the use of appropriate hydraulic structures (canals, shipping locks), then is lowered on the basement constructed beforehand and incorporated into NPP scheme, of which the components are installed in advance. Floating means can be detached from the RCBM and used repeatedly for other RCBMs. Further procedure of NPP commissioning and its operation is carried out according to traditional method by power company in the framework of RCBM leasing with enlisting the services of firm-manufacturer's specialists either to provide reactor plant operation and concomitant processes or to perform author's supervision of operation. After completion of lifetime and reactor unloading the RCBM is dismantled with using the same afloat technology and taken away from NPP site to sea area entirely, together with its structures (reactor vessel, heat exchangers, pumps, pipelines and other equipment). Then RCBM is transported by shipping route to a firm

Hydraulic lift as a determinant of tree-grass coexistence on savannas.

PubMed

Yu, Kailiang; D'Odorico, Paolo

2015-09-01

The coexistence of woody plants and grasses in savannas is determined by a complex set of interacting factors that determine access to resources and demographic dynamics, under the control of external drivers and vegetation feedbacks with the physical environment. Existing theories explain coexistence mainly as an effect of competitive relations and/or disturbances. However, theoretical studies on the way facilitative interactions resulting from hydraulic lift affect tree-grass coexistence and the range of environmental conditions in which savannas are stable are still lacking. We investigated the role of hydraulic lift in the stability of tree-grass coexistence in savannas. To that end, we developed a new mechanistic model that accounts for both competition for soil water in the shallow soil and fire-induced disturbance. We found that hydraulic lift favors grasses, which scavenge the water lifted by woody plants. Thus, hydraulic lift expands (at the expenses of woodlands) the range of environmental conditions in which savannas are stable. These results indicate that hydraulic lift can be an important mechanism responsible for the coexistence of woody plants and grasses in savannas. Grass facilitation by trees through the process of hydraulic lift could allow savannas to persist stably in mesic regions that would otherwise exhibit a forest cover. © 2015 The Authors. New Phytologist © 2015 New Phytologist Trust.

Application of simple adaptive control to water hydraulic servo cylinder system

NASA Astrophysics Data System (ADS)

Ito, Kazuhisa; Yamada, Tsuyoshi; Ikeo, Shigeru; Takahashi, Koji

2012-09-01

Although conventional model reference adaptive control (MRAC) achieves good tracking performance for cylinder control, the controller structure is much more complicated and has less robustness to disturbance in real applications. This paper discusses the use of simple adaptive control (SAC) for positioning a water hydraulic servo cylinder system. Compared with MRAC, SAC has a simpler and lower order structure, i.e., higher feasibility. The control performance of SAC is examined and evaluated on a water hydraulic servo cylinder system. With the recent increased concerns over global environmental problems, the water hydraulic technique using pure tap water as a pressure medium has become a new drive source comparable to electric, oil hydraulic, and pneumatic drive systems. This technique is also preferred because of its high power density, high safety against fire hazards in production plants, and easy availability. However, the main problems for precise control in a water hydraulic system are steady state errors and overshoot due to its large friction torque and considerable leakage flow. MRAC has been already applied to compensate for these effects, and better control performances have been obtained. However, there have been no reports on the application of SAC for water hydraulics. To make clear the merits of SAC, the tracking control performance and robustness are discussed based on experimental results. SAC is confirmed to give better tracking performance compared with PI control, and a control precision comparable to MRAC (within 10 μm of the reference position) and higher robustness to parameter change, despite the simple controller. The research results ensure a wider application of simple adaptive control in real mechanical systems.

Martin Drake power plant

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

Schimmoller, B.K.

2005-08-01

The relatively old Martin Drake coal-fired plant at Colorado Springs is facing challenges to meet environmental requirements whilst satisfying power demands and remaining competition. The article describes measures taken and planned to tackle these challenges. 2 photos.

15. Power copy of drawing, August 21, 1915. POWER PLANT ...

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

15. Power copy of drawing, August 21, 1915. POWER PLANT EXTENSION, GENERAL PLANS. Drawing No. PA-A-36692, Facilities Engineering, Army Materials Technology Laboratory, Watertown, Massachusetts. - Watertown Arsenal, Building No. 60, Arsenal Street, Watertown, Middlesex County, MA

Steady-State Plant Model to Predict Hydroden Levels in Power Plant Components

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

Glatzmaier, Greg C.; Cable, Robert; Newmarker, Marc

The National Renewable Energy Laboratory (NREL) and Acciona Energy North America developed a full-plant steady-state computational model that estimates levels of hydrogen in parabolic trough power plant components. The model estimated dissolved hydrogen concentrations in the circulating heat transfer fluid (HTF), and corresponding partial pressures within each component. Additionally for collector field receivers, the model estimated hydrogen pressure in the receiver annuli. The model was developed to estimate long-term equilibrium hydrogen levels in power plant components, and to predict the benefit of hydrogen mitigation strategies for commercial power plants. Specifically, the model predicted reductions in hydrogen levels within the circulatingmore » HTF that result from purging hydrogen from the power plant expansion tanks at a specified target rate. Our model predicted hydrogen partial pressures from 8.3 mbar to 9.6 mbar in the power plant components when no mitigation treatment was employed at the expansion tanks. Hydrogen pressures in the receiver annuli were 8.3 to 8.4 mbar. When hydrogen partial pressure was reduced to 0.001 mbar in the expansion tanks, hydrogen pressures in the receiver annuli fell to a range of 0.001 mbar to 0.02 mbar. When hydrogen partial pressure was reduced to 0.3 mbar in the expansion tanks, hydrogen pressures in the receiver annuli fell to a range of 0.25 mbar to 0.28 mbar. Our results show that controlling hydrogen partial pressure in the expansion tanks allows us to reduce and maintain hydrogen pressures in the receiver annuli to any practical level.« less

The Relationship of Temporal Variations in SMAP Vegetation Optical Depth to Plant Hydraulic Behavior

NASA Astrophysics Data System (ADS)

Konings, A. G.

2016-12-01

The soil emissions measured by L-band radiometers such as that on the NASA Soil Moisture Active/Passive mission are modulated by vegetation cover as quantified by the soil scattering albedo and the vegetation optical depth (VOD). The VOD is linearly proportional to the total vegetation water content, which is dependent on both the biomass and relative water content of the plant. Biomass is expected to vary more slowly than water content. Variations in vegetation water content are highly informative as they are directly indicative of the degree of hydraulic stress (or lack thereof) experienced by the plant. However, robust retrievals are needed in order for SMAP VOD observations to be useful. This is complicated by the fact that multiple unknowns (soil moisture, VOD, and albedo) need to be determined from two highly correlated polarizations. This presentation will discuss the application to SMAP of a recently developed timeseries algorithm for VOD and albedo retrieval - the Multi-Temporal Dual Channel Algorithm MTDCA, and its interpretation for plant hydraulic applications. The MT-DCA is based on the assumption that, for consecutive overpasses at a given time of day, VOD varies more slowly than soil moisture. A two-overpass moving average can then be used to determine variations in VOD that are less sensitive to high-frequency noise than classical dual-channel algorithms. Seasonal variations of SMAP VOD are presented and compared to expected patterns based on rainfall and radiation seasonality. Taking advantage of the large diurnal variation (relative to the seasonal variation) of canopy water potention, diurnal variations (between 6AM and 6PM observations) of SMAP VOD are then used to calculate global variations in ecosystem-scale isohydricity - the degree of stomatal closure and xylem conductivity loss in response to water stress. Lastly, the effect of satellite sensing frequency and overpass time on water content across canopies of different height will be

CHANGES IN TERRESTRIAL ECOLOGY RELATED TO A COAL-FIRED POWER PLANT: WISCONSIN POWER PLANT IMPACT STUDY

EPA Science Inventory

This report summarizes the effects of a coal-fired power plant on terrestrial plants and animals. Research was conducted from 1971 through 1977 at the Columbia Generating Station in the eastern flood-plain of the Wisconsin River in south-central Wisconsin. Initial studies were la...

ALARA at nuclear power plants

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

Baum, J.W.

1990-01-01

Implementation of the As Low As Reasonably Achievable (ALARA) principle at nuclear power plants presents a continuing challenge for health physicists at utility corporate and plant levels, for plant designers, and for regulatory agencies. The relatively large collective doses at some plants are being addressed though a variety of dose reduction techniques. It is planned that this report will include material on historical aspects, management, valuation of dose reduction, quantitative and qualitative aspects of optimization, design, operational considerations, and training. The status of this work is summarized in this report. 30 refs., 1 fig., 6 tabs.

Structural considerations for underground nuclear power plants

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

Sarne, Y.

The advantages and disadvantages of underground nuclear power plants are briefly reviewed. The impact of underground contruction on plant layout and structural design are discussed. Schedules and costs for construction are compared with those for conventional plants.

76 FR 75771 - Emergency Planning Guidance for Nuclear Power Plants

Federal Register 2010, 2011, 2012, 2013, 2014

2011-12-05

... Guidance for Nuclear Power Plants AGENCY: Nuclear Regulatory Commission. ACTION: Issuance of NUREG... Support of Nuclear Power Plants;'' NSIR/DPR-ISG-01, ``Interim Staff Guidance Emergency Planning for Nuclear Power Plants;'' and NUREG/CR-7002, ``Criteria for Development of Evacuation Time Estimate Studies...

Stem and leaf hydraulic properties are finely coordinated in three tropical rain forest tree species.

PubMed

Nolf, Markus; Creek, Danielle; Duursma, Remko; Holtum, Joseph; Mayr, Stefan; Choat, Brendan

2015-12-01

Coordination of stem and leaf hydraulic traits allows terrestrial plants to maintain safe water status under limited water supply. Tropical rain forests, one of the world's most productive biomes, are vulnerable to drought and potentially threatened by increased aridity due to global climate change. However, the relationship of stem and leaf traits within the plant hydraulic continuum remains understudied, particularly in tropical species. We studied within-plant hydraulic coordination between stems and leaves in three tropical lowland rain forest tree species by analyses of hydraulic vulnerability [hydraulic methods and ultrasonic emission (UE) analysis], pressure-volume relations and in situ pre-dawn and midday water potentials (Ψ). We found finely coordinated stem and leaf hydraulic features, with a strategy of sacrificing leaves in favour of stems. Fifty percent of hydraulic conductivity (P50 ) was lost at -2.1 to -3.1 MPa in stems and at -1.7 to -2.2 MPa in leaves. UE analysis corresponded to hydraulic measurements. Safety margins (leaf P50 - stem P50 ) were very narrow at -0.4 to -1.4 MPa. Pressure-volume analysis and in situ Ψ indicated safe water status in stems but risk of hydraulic failure in leaves. Our study shows that stem and leaf hydraulics were finely tuned to avoid embolism formation in the xylem. © 2015 John Wiley & Sons Ltd.

Evaluation of Hybrid Power Plants using Biomass, Photovoltaics and Steam Electrolysis for Hydrogen and Power Generation

NASA Astrophysics Data System (ADS)

Petrakopoulou, F.; Sanz, J.

2014-12-01

Steam electrolysis is a promising process of large-scale centralized hydrogen production, while it is also considered an excellent option for the efficient use of renewable solar and geothermal energy resources. This work studies the operation of an intermediate temperature steam electrolyzer (ITSE) and its incorporation into hybrid power plants that include biomass combustion and photovoltaic panels (PV). The plants generate both electricity and hydrogen. The reference -biomass- power plant and four variations of a hybrid biomass-PV incorporating the reference biomass plant and the ITSE are simulated and evaluated using exergetic analysis. The variations of the hybrid power plants are associated with (1) the air recirculation from the electrolyzer to the biomass power plant, (2) the elimination of the sweep gas of the electrolyzer, (3) the replacement of two electric heaters with gas/gas heat exchangers, and (4) the replacement two heat exchangers of the reference electrolyzer unit with one heat exchanger that uses steam from the biomass power plant. In all cases, 60% of the electricity required in the electrolyzer is covered by the biomass plant and 40% by the photovoltaic panels. When comparing the hybrid plants with the reference biomass power plant that has identical operation and structure as that incorporated in the hybrid plants, we observe an efficiency decrease that varies depending on the scenario. The efficiency decrease stems mainly from the low effectiveness of the photovoltaic panels (14.4%). When comparing the hybrid scenarios, we see that the elimination of the sweep gas decreases the power consumption due to the elimination of the compressor used to cover the pressure losses of the filter, the heat exchangers and the electrolyzer. Nevertheless, if the sweep gas is used to preheat the air entering the boiler of the biomass power plant, the efficiency of the plant increases. When replacing the electric heaters with gas-gas heat exchangers, the

Degradation of Phosphate Ester Hydraulic Fluid in Power Station Turbines Investigated by a Three-Magnet Unilateral Magnet Array

PubMed Central

Guo, Pan; He, Wei; García-Naranjo, Juan C.

2014-01-01

A three-magnet array unilateral NMR sensor with a homogeneous sensitive spot was employed for assessing aging of the turbine oils used in two different power stations. The Carr-Purcell-Meiboom-Gill (CPMG) sequence and Inversion Recovery-prepared CPMG were employed for measuring the 1H-NMR transverse and longitudinal relaxation times of turbine oils with different service status. Two signal components with different lifetimes were obtained by processing the transverse relaxation curves with a numeric program based on the Inverse Laplace Transformation. The long lifetime components of the transverse relaxation time T2eff and longitudinal relaxation time T1 were chosen to monitor the hydraulic fluid aging. The results demonstrate that an increase of the service time of the turbine oils clearly results in a decrease of T2eff,long and T1,long. This indicates that the T2eff,long and T1,long relaxation times, obtained from the unilateral magnetic resonance measurements, can be applied as indices for degradation of the hydraulic fluid in power station turbines. PMID:24736132

Adaptive Neural Network Algorithm for Power Control in Nuclear Power Plants

NASA Astrophysics Data System (ADS)

Masri Husam Fayiz, Al

2017-01-01

The aim of this paper is to design, test and evaluate a prototype of an adaptive neural network algorithm for the power controlling system of a nuclear power plant. The task of power control in nuclear reactors is one of the fundamental tasks in this field. Therefore, researches are constantly conducted to ameliorate the power reactor control process. Currently, in the Department of Automation in the National Research Nuclear University (NRNU) MEPhI, numerous studies are utilizing various methodologies of artificial intelligence (expert systems, neural networks, fuzzy systems and genetic algorithms) to enhance the performance, safety, efficiency and reliability of nuclear power plants. In particular, a study of an adaptive artificial intelligent power regulator in the control systems of nuclear power reactors is being undertaken to enhance performance and to minimize the output error of the Automatic Power Controller (APC) on the grounds of a multifunctional computer analyzer (simulator) of the Water-Water Energetic Reactor known as Vodo-Vodyanoi Energetichesky Reaktor (VVER) in Russian. In this paper, a block diagram of an adaptive reactor power controller was built on the basis of an intelligent control algorithm. When implementing intelligent neural network principles, it is possible to improve the quality and dynamic of any control system in accordance with the principles of adaptive control. It is common knowledge that an adaptive control system permits adjusting the controller’s parameters according to the transitions in the characteristics of the control object or external disturbances. In this project, it is demonstrated that the propitious options for an automatic power controller in nuclear power plants is a control system constructed on intelligent neural network algorithms.

Proposed Minor NSR Permit: Deseret Power Electric Cooperative - Bonanza Power Plant

EPA Pesticide Factsheets

Proposed minor NSR permit, technical support document, public notice bulletin, and supporting documentation for the Deseret Power Electric Cooperative Bonanza Power Plant, Uintah and Ouray Indian Reservation, Utah.

Energy analysis of coal, fission, and fusion power plants

NASA Astrophysics Data System (ADS)

Tsoulfanidis, N.

1981-04-01

The method of net energy analysis has been applied to coal, fission, and fusion power plants. Energy consumption over the lifetime of the plants has been calculated for construction, operation and maintenance, fuel, public welfare, and land use and restoration. Thermal and electric energy requirements were obtained separately for each energy consuming sector. The results of the study are presented in three ways: total energy requirements, energy gain ratio, and payback periods. All three types of power plants are net producers of energy. The coal and fusion power plants are superior to fission plants from the energy efficiency point of view. Fission plants will improve considerably if the centrifuge replaces the gaseous diffusion as a method of enrichment.

Influence of geographic setting on thermal discharge from coastal power plants.

PubMed

Jia, Hou-Lei; Zheng, Shu; Xie, Jian; Ying, Xiao-Ming; Zhang, Cui-Ping

2016-10-15

Characteristics of thermal discharge from three coastal power plants were studied in China. The three plants, Zhuhai Power Plant, Chaozhou Power Plant and Huilai Power Plant, are located in estuary, bay and open sea, respectively. The water temperatures and ocean currents surrounding the outlet of the three power plants were monitored. The results show that the temperature rise became smaller as the spread of thermal discharge moved toward the open sea, which confirms the results of previous studies. The results also indicated that the influence range of thermal discharge from a coastal power plant is determined by geographic setting. The temperature rise range of the Chaozhou Plant, which is located in a bay, was the largest, followed by that of the Zhuhai Plant located in an estuary, and the temperature rise range of the Huilai Plant located in an open sea was the smallest. Copyright © 2016 Elsevier Ltd. All rights reserved.

TOPICAL REVIEW: Pneumatic and hydraulic microactuators: a review

NASA Astrophysics Data System (ADS)

De Volder, Michaël; Reynaerts, Dominiek

2010-04-01

The development of MEMS actuators is rapidly evolving and continuously new progress in terms of efficiency, power and force output is reported. Pneumatic and hydraulic are an interesting class of microactuators that are easily overlooked. Despite the 20 years of research, and hundreds of publications on this topic, these actuators are only popular in microfluidic systems. In other MEMS applications, pneumatic and hydraulic actuators are rare in comparison with electrostatic, thermal or piezo-electric actuators. However, several studies have shown that hydraulic and pneumatic actuators deliver among the highest force and power densities at microscale. It is believed that this asset is particularly important in modern industrial and medical microsystems, and therefore, pneumatic and hydraulic actuators could start playing an increasingly important role. This paper shows an in-depth overview of the developments in this field ranging from the classic inflatable membrane actuators to more complex piston-cylinder and drag-based microdevices.

Rocket Power Plants Based on Nitric Acid and their Specific Propulsive Weights

NASA Technical Reports Server (NTRS)

Zborowski, Helmut

1947-01-01

Two fields are reserved for the application of rocket power plants. The first field is determined by the fact that the rocket power plant is the only type of power plant that can produce thrust without dependence upon environment. For this field,the rocket is therefore the only possible power plant and the limit of what may be done is determined by the status of the technical development of these power plants at the given moment. The second field is that in which the rocket power plant proves itself the most suitable as a high-power drive in free competition with other types of power plants. The exposition will be devoted to the demarcation of this field and its division among the various types of rocket power plants.

Thermal storage requirements for parabolic dish solar power plants

NASA Technical Reports Server (NTRS)

Wen, L.; Steele, H.

1980-01-01

The cost effectiveness of a high temperature thermal storage system is investigated for a representative parabolic dish solar power plant. The plant supplies electrical power in accordance with a specific, seasonally varying demand profile. The solar power received by the plant is supplemented by power from fuel combustion. The cost of electricity generated by the solar power plant is calculated, using the cost of mass-producible subsystems (specifically, parabolic dishes, receivers, and power conversion units) now being designed for this type of solar plant. The trade-off between fuel and thermal storage is derived in terms of storage effectiveness, the cost of storage devices, and the cost of fuel. Thermal storage requirements, such as storage capacity, storage effectiveness, and storage cost are established based on the cost of fuel and the overall objective of minimizing the cost of the electricity produced by the system. As the cost of fuel increases at a rate faster than general inflation, thermal storage systems in the $40 to $70/kWthr range could become cost effective in the near future.

The Integrated Role of Water Availability, Nutrient Dynamics, and Xylem Hydraulic Dysfunction on Plant Rooting Strategies in Managed and Natural Ecosystems

NASA Astrophysics Data System (ADS)

Mackay, D. S.; Savoy, P.; Pleban, J. R.; Tai, X.; Ewers, B. E.

2015-12-01

Plants adapt or acclimate to changing environments in part by allocating biomass to roots and leaves to strike a balance between water and nutrient uptake requirements on the one hand and growth and hydraulic safety on the other hand. In a recent study examining experimental drought with the TREES model, which couples plant ecophysiology with rhizosphere-and-xylem hydraulics, we hypothesized that the asynchronous nature of soil water availability and xylem repair supported root-to-leaf area (RLA) proportionality that favored long-term survival over short-term carbon gain or water use. To investigate this as a possible general principal of plant adjustment to changing environmental conditions, TREES was modified to allocate carbon to fine and coarse roots organized in ten orders differing in biomass allocated per unit absorbing root area, root lifespan, and total absorbing root area in each of several soil-root zones with depth. The expanded model allowed for adjustment of absorbing root area and rhizosphere volume based on available carbohydrate production and nitrogen (N) availability, resulting in dynamic expansion and contraction of the supply-side of the rhizosphere-plant hydraulics and N uptake capacity in response to changing environmental conditions and plant-environment asynchrony. The study was conducted partly in a controlled experimental setting with six genotypes of a widely grown crop species, Brassica rapa. The implications for forests were investigated in controlled experiments and at Fluxnet sites representing temperate mixed forests, semi-arid evergreen needle-leaf, and Mediterranean biomes. The results showed that the effects of N deficiency on total plant growth was modulated by a relative increase in fine root biomass representing a larger absorbing root volume per unit biomass invested. We found that the total absorbing root area per unit leaf area was consistently lower than that needed to maximize short-term water uptake and carbohydrate gain

Morphology and Hydraulic Architecture of Vitis vinifera L. cv. Syrah and Torrontés Riojano Plants Are Unaffected by Variations in Red to Far-Red Ratio

PubMed Central

González, Carina Verónica; Jofré, María Florencia; Vila, Hernán F.; Stoffel, Markus; Bottini, Rubén; Giordano, Carla Valeria

2016-01-01

Plants have evolved an array of specific photoreceptors to acclimate to the light environment. By sensing light signals, photoreceptors modulate plant morphology, carbon- and water-physiology, crop yield and quality of harvestable organs, among other responses. Many cultural practices and crop management decisions alter light quantity and quality perceived by plants cultivated in the field. Under full sunlight, phytochromes perceive high red to far red ratios (R:FR; 1.1), whereas overhead or lateral low R:FR (below 1.1) are sensed in the presence of plant shade or neighboring plants, respectively. Grapevine is one of the most important fruit crops in the world. To date, studies on grapevine response to light focused on different Photosynthetic Active Radiation (PAR) levels; however, limited data exist about its response to light quality. In this study we aimed to investigate morphological, biochemical, and hydraulic responses of Vitis vinifera to variations in R:FR. Therefore, we irradiated Syrah and Torrontés Riojano plants, grown in a glasshouse, with lateral FR light (low lateral R:FR treatment), while others, that were kept as controls, were not irradiated (ambient lateral R:FR treatment). In response to the low lateral R:FR treatment, grapevine plants did not display any of the SAS morphological markers (i.e. stem length, petiole length and angle, number of lateral shoots) in any of the cultivars assessed, despite an increase in gibberelins and auxin concentrations in leaf tissues. Low lateral R:FR did not affect dry matter partitioning, water-related traits (stomata density and index, wood anatomy), or water-related physiology (plant conductance, transpiration rate, stem hydraulic conductivity, stomatal conductance). None of the Vitis vinifera varieties assessed displayed the classical morphological and hydraulic responses associated to SAS induced by phytochromes. We discuss these results in the context of natural grapevine environment and agronomical

Morphology and Hydraulic Architecture of Vitis vinifera L. cv. Syrah and Torrontés Riojano Plants Are Unaffected by Variations in Red to Far-Red Ratio.

PubMed

González, Carina Verónica; Jofré, María Florencia; Vila, Hernán F; Stoffel, Markus; Bottini, Rubén; Giordano, Carla Valeria

2016-01-01

Plants have evolved an array of specific photoreceptors to acclimate to the light environment. By sensing light signals, photoreceptors modulate plant morphology, carbon- and water-physiology, crop yield and quality of harvestable organs, among other responses. Many cultural practices and crop management decisions alter light quantity and quality perceived by plants cultivated in the field. Under full sunlight, phytochromes perceive high red to far red ratios (R:FR; 1.1), whereas overhead or lateral low R:FR (below 1.1) are sensed in the presence of plant shade or neighboring plants, respectively. Grapevine is one of the most important fruit crops in the world. To date, studies on grapevine response to light focused on different Photosynthetic Active Radiation (PAR) levels; however, limited data exist about its response to light quality. In this study we aimed to investigate morphological, biochemical, and hydraulic responses of Vitis vinifera to variations in R:FR. Therefore, we irradiated Syrah and Torrontés Riojano plants, grown in a glasshouse, with lateral FR light (low lateral R:FR treatment), while others, that were kept as controls, were not irradiated (ambient lateral R:FR treatment). In response to the low lateral R:FR treatment, grapevine plants did not display any of the SAS morphological markers (i.e. stem length, petiole length and angle, number of lateral shoots) in any of the cultivars assessed, despite an increase in gibberelins and auxin concentrations in leaf tissues. Low lateral R:FR did not affect dry matter partitioning, water-related traits (stomata density and index, wood anatomy), or water-related physiology (plant conductance, transpiration rate, stem hydraulic conductivity, stomatal conductance). None of the Vitis vinifera varieties assessed displayed the classical morphological and hydraulic responses associated to SAS induced by phytochromes. We discuss these results in the context of natural grapevine environment and agronomical

Understanding, Classifying, and Selecting Environmentally Acceptable Hydraulic Fluids

DTIC Science & Technology

2016-08-01

installed in land facilities or off- road vehicles such as excavators, bulldozers, backhoes, etc.), while others are installed on floating plants...and oily bilge tanks for the collection and proper disposal of oil- contaminated bilge water • Performing routine maintenance , including regular...regulations. Maintenance of machinery systems containing EA hydraulic fluids must strictly follow the hydraulic fluid manufacturer’s recommendations

Plant hydraulic responses to long-term dry season nitrogen deposition alter drought tolerance in a Mediterranean-type ecosystem.

PubMed

Pivovaroff, Alexandria L; Santiago, Louis S; Vourlitis, George L; Grantz, David A; Allen, Michael F

2016-07-01

Anthropogenic nitrogen (N) deposition represents a significant N input for many terrestrial ecosystems. N deposition can affect plants on scales ranging from photosynthesis to community composition, yet few studies have investigated how changes in N availability affect plant water relations. We tested the effects of N addition on plant water relations, hydraulic traits, functional traits, gas exchange, and leaf chemistry in a semi-arid ecosystem in Southern California using long-term experimental plots fertilized with N for over a decade. The dominant species were Artemisia california and Salvia mellifera at Santa Margarita Ecological Reserve and Adenostoma fasciculatum and Ceanothus greggii at Sky Oaks Field Station. All species, except Ceanothus, showed increased leaf N concentration, decreased foliar carbon to N ratio, and increased foliar N isotopic composition with fertilization, indicating that added N was taken up by study species, yet each species had a differing physiological response to long-term N addition. Dry season predawn water potentials were less negative with N addition for all species except Adenostoma, but there were no differences in midday water potentials, or wet season water potentials. Artemisia was particularly responsive, as N addition increased stem hydraulic conductivity, stomatal conductance, and leaf carbon isotopic composition, and decreased wood density. The alteration of water relations and drought resistance parameters with N addition in Artemisia, as well as Adenostoma, Ceanothus, and Salvia, indicate that N deposition can affect the ability of native Southern California shrubs to respond to drought.

Wind Power Plant SCADA and Controls

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

Badrzadeh, Babak; Castillo, Nestor; Bradt, M.

2011-01-01

Modern Wind Power Plants (WPPs) contain a variety of intelligent electronic devices (IEDs), Supervisory Control and Data Acquisition (SCADA) and communication systems. This paper discusses the issues related to a typical WPP's SCADA and Control. Presentation topics are: (1) Wind Turbine Controls; (2) Wind Plant SCADA, OEM SCADA Solutions, Third-Party SCADA Solutions; (3) Wind Plant Control; and (4) Security and Reliability Compliance.

Parametric study of potential early commercial MHD power plants

NASA Technical Reports Server (NTRS)

Hals, F. A.

1979-01-01

Three different reference power plant configurations were considered with parametric variations of the various design parameters for each plant. Two of the reference plant designs were based on the use of high temperature regenerative air preheaters separately fired by a low Btu gas produced from a coal gasifier which was integrated with the power plant. The third reference plant design was based on the use of oxygen enriched combustion air preheated to a more moderate temperature in a tubular type metallic recuperative heat exchanger which is part of the bottoming plant heat recovery system. Comparative information was developed on plant performance and economics. The highest net plant efficiency of about 45 percent was attained by the reference plant design with the use of a high temperature air preheater separately fired with the advanced entrained bed gasifier. The use of oxygen enrichment of the combustion air yielded the lowest cost of generating electricity at a slightly lower plant efficiency. Both of these two reference plant designs are identified as potentially attractive for early MHD power plant applications.

Westinghouse ICF power plant study

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

Sucov, E. W.

1980-10-01

In this study, two different electric power plants for the production of about 1000 MWe which were based on a CO/sub 2/ laser driver and on a heavy ion driver have been developed and analyzed. The purposes of this study were: (1) to examine in a self consistent way the technological and institutional problems that need to be confronted and solved in order to produce commercially competitive electricity in the 2020 time frame from an inertial fusion reactor, and (2) to compare, on a common basis, the consequences of using two different drivers to initiate the DT fuel pellet explosions.more » Analytic descriptions of size/performance/cost relationships for each of the subsystems comprising the power plant have been combined into an overall computer code which models the entire plant. This overall model has been used to conduct trade studies which examine the consequences of varying critical design values around the reference point.« less

Arabidopsis thaliana as a model species for xylem hydraulics: does size matter?

PubMed Central

Tixier, Aude; Cochard, Hervé; Badel, Eric; Dusotoit-Coucaud, Anaïs; Jansen, Steven; Herbette, Stéphane

2013-01-01

While Arabidopsis thaliana has been proposed as a model species for wood development, the potential of this tiny herb for studying xylem hydraulics remains unexplored and anticipated by scepticism. Inflorescence stems of A. thaliana were used to measure hydraulic conductivity and cavitation resistance, whereas light and electron microscopy allowed observations of vessels. In wild-type plants, measured and theoretical conductivity showed a significant correlation (R 2 = 0.80, P < 0.01). Moreover, scaling of vessel dimensions and intervessel pit structure of A. thaliana were consistent with structure–function relationships of woody plants. The reliability and resolution of the hydraulic methods applied to measure vulnerability to cavitation were addressed by comparing plants grown under different photoperiods or different mutant lines. Sigmoid vulnerability curves of A. thaliana indicated a pressure corresponding to 50% loss of hydraulic conductance (P 50) between –3 and –2.5MPa for short-day and long-day plants, respectively. Polygalacturonase mutants showed a higher P 50 value (–2.25MPa), suggesting a role for pectins in vulnerability to cavitation. The application of A. thaliana as a model species for xylem hydraulics provides exciting possibilities for (1) exploring the molecular basis of xylem anatomical features and (2) understanding genetic mechanisms behind xylem functional traits such as cavitation resistance. Compared to perennial woody species, however, the lesser amount of xylem in A. thaliana has its limitations. PMID:23547109

Arabidopsis thaliana as a model species for xylem hydraulics: does size matter?

PubMed

Tixier, Aude; Cochard, Hervé; Badel, Eric; Dusotoit-Coucaud, Anaïs; Jansen, Steven; Herbette, Stéphane

2013-05-01

While Arabidopsis thaliana has been proposed as a model species for wood development, the potential of this tiny herb for studying xylem hydraulics remains unexplored and anticipated by scepticism. Inflorescence stems of A. thaliana were used to measure hydraulic conductivity and cavitation resistance, whereas light and electron microscopy allowed observations of vessels. In wild-type plants, measured and theoretical conductivity showed a significant correlation (R (2) = 0.80, P < 0.01). Moreover, scaling of vessel dimensions and intervessel pit structure of A. thaliana were consistent with structure-function relationships of woody plants. The reliability and resolution of the hydraulic methods applied to measure vulnerability to cavitation were addressed by comparing plants grown under different photoperiods or different mutant lines. Sigmoid vulnerability curves of A. thaliana indicated a pressure corresponding to 50% loss of hydraulic conductance (P 50) between -3 and -2.5MPa for short-day and long-day plants, respectively. Polygalacturonase mutants showed a higher P 50 value (-2.25MPa), suggesting a role for pectins in vulnerability to cavitation. The application of A. thaliana as a model species for xylem hydraulics provides exciting possibilities for (1) exploring the molecular basis of xylem anatomical features and (2) understanding genetic mechanisms behind xylem functional traits such as cavitation resistance. Compared to perennial woody species, however, the lesser amount of xylem in A. thaliana has its limitations.

Compressed Natural Gas Technology for Alternative Fuel Power Plants

NASA Astrophysics Data System (ADS)

Pujotomo, Isworo

2018-02-01

Gas has great potential to be converted into electrical energy. Indonesia has natural gas reserves up to 50 years in the future, but the optimization of the gas to be converted into electricity is low and unable to compete with coal. Gas is converted into electricity has low electrical efficiency (25%), and the raw materials are more expensive than coal. Steam from a lot of wasted gas turbine, thus the need for utilizing exhaust gas results from gas turbine units. Combined cycle technology (Gas and Steam Power Plant) be a solution to improve the efficiency of electricity. Among other Thermal Units, Steam Power Plant (Combined Cycle Power Plant) has a high electrical efficiency (45%). Weakness of the current Gas and Steam Power Plant peak burden still using fuel oil. Compressed Natural Gas (CNG) Technology may be used to accommodate the gas with little land use. CNG gas stored in the circumstances of great pressure up to 250 bar, in contrast to gas directly converted into electricity in a power plant only 27 bar pressure. Stored in CNG gas used as a fuel to replace load bearing peak. Lawyer System on CNG conversion as well as the power plant is generally only used compressed gas with greater pressure and a bit of land.

Study on the hydraulic characteristics of side inlet/outlet by physical model test

NASA Astrophysics Data System (ADS)

Kong, Bo; Ye, Fei; Hu, Qiu-yue; Zhang, Jing

2017-04-01

The hydraulic characteristics at the side inlet/outlet of pumped storage plants were studied by physical model test. The gravity similarity rule was adopted and head loss coefficients under pumped and power conditions were given. The flow distribution under both conditions was studied. Scheme of changing the separation pier section area proportion for minimizing velocity uneven coefficient was brought forward and the cause of test error was researched. Vortex evaluation and observation were studied under the pumped condition at normal and dead reservoir water levels.

Nuclear Power Plant Technician

ERIC Educational Resources Information Center

Randall, George A.

1975-01-01

The author recognizes a body of basic knowledge in nuclear power plant technoogy that can be taught in school programs, and lists the various courses, aiming to fill the anticipated need for nuclear-trained manpower--persons holding an associate degree in engineering technology. (Author/BP)

Economic and hydraulic divergences underpin ecological differentiation in the Bromeliaceae.

PubMed

Males, Jamie; Griffiths, Howard

2018-01-01

Leaf economic and hydraulic theories have rarely been applied to the ecological differentiation of speciose herbaceous plant radiations. The role of character trait divergences and network reorganization in the differentiation of the functional types in the megadiverse Neotropical Bromeliaceae was explored by quantifying a range of leaf economic and hydraulic traits in 50 diverse species. Functional types, which are defined by combinations of C 3 or Crassulacean acid metabolism (CAM) photosynthesis, terrestrial or epiphytic habits, and non-specialized, tank-forming or atmospheric morphologies, segregated clearly in trait space. Most classical leaf economic relationships were supported, but they were weakened by the presence of succulence. Functional types differed in trait-network architecture, suggesting that rewiring of trait-networks caused by innovations in habit and photosynthetic pathway is an important aspect of ecological differentiation. The hydraulic data supported the coupling of leaf hydraulics and gas exchange, but not the hydraulic safety versus efficiency hypothesis, and hinted at an important role for the extra-xylary compartment in the control of bromeliad leaf hydraulics. Overall, our findings highlight the fundamental importance of structure-function relationships in the generation and maintenance of ecological diversity. © 2017 The Authors Plant, Cell & Environment Published by John Wiley & Sons Ltd.

Performance calculations for 200-1000 MWe MHD/steam power plants

NASA Technical Reports Server (NTRS)

Staiger, P. J.

1981-01-01

The effects of MHD generator length, level of oxygen enrichment, and oxygen production power on the performance of MHD/steam power plants ranging from 200 to 1000 MW in electrical output are investigated. The plants considered use oxygen enriched combustion air preheated to 1100 F. Both plants in which the MHD generator is cooled with low temperature and pressure boiler feedwater and plants in which the generator is cooled with high temperature and pressure boiler feedwater are considered. For plants using low temperature boiler feedwater for generator cooling the maximum thermodynamic efficiency is obtained with shorter generators and a lower level of oxygen enrichment compared to plants using high temperature boiler feedwater for generator cooling. The generator length at which the maximum plant efficiency occurs increases with power plant size for plants with a generator cooled by low temperature feedwater. Also shown is the relationship of the magnet stored energy requirement of the generator length and the power plant performance. Possible cost/performance tradeoffs between magnet cost and plant performance are indicated.

Experiences with the hydraulic design of the high specific speed Francis turbine

NASA Astrophysics Data System (ADS)

Obrovsky, J.; Zouhar, J.

2014-03-01

The high specific speed Francis turbine is still suitable alternative for refurbishment of older hydro power plants with lower heads and worse cavitation conditions. In the paper the design process of such kind of turbine together with the results comparison of homological model tests performed in hydraulic laboratory of ČKD Blansko Engineering is introduced. The turbine runner was designed using the optimization algorithm and considering the high specific speed hydraulic profile. It means that hydraulic profiles of the spiral case, the distributor and the draft tube were used from a Kaplan turbine. The optimization was done as the automatic cycle and was based on a simplex optimization method as well as on a genetic algorithm. The number of blades is shown as the parameter which changes the resulting specific speed of the turbine between ns=425 to 455 together with the cavitation characteristics. Minimizing of cavitation on the blade surface as well as on the inlet edge of the runner blade was taken into account during the design process. The results of CFD analyses as well as the model tests are mentioned in the paper.

Analysis on energy consumption index system of thermal power plant

NASA Astrophysics Data System (ADS)

Qian, J. B.; Zhang, N.; Li, H. F.

2017-05-01

Currently, the increasingly tense situation in the context of resources, energy conservation is a realistic choice to ease the energy constraint contradictions, reduce energy consumption thermal power plants has become an inevitable development direction. And combined with computer network technology to build thermal power “small index” to monitor and optimize the management system, the power plant is the application of information technology and to meet the power requirements of the product market competition. This paper, first described the research status of thermal power saving theory, then attempted to establish the small index system and build “small index” monitoring and optimization management system in thermal power plant. Finally elaborated key issues in the field of small thermal power plant technical and economic indicators to be further studied and resolved.

Geothermal Risk Reduction via Geothermal/Solar Hybrid Power Plants. Final Report

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

Wendt, Daniel; Mines, Greg; Turchi, Craig

There are numerous technical merits associated with a renewable geothermal-solar hybrid plant concept. The performance of air-cooled binary plants is lowest when ambient temperatures are high due to the decrease in air-cooled binary plant performance that occurs when the working fluid condensing temperature, and consequently the turbine exhaust pressure, increases. Electrical power demand is generally at peak levels during periods of elevated ambient temperature and it is therefore especially important to utilities to be able to provide electrical power during these periods. The time periods in which air-cooled binary geothermal power plant performance is lowest generally correspond to periods ofmore » high solar insolation. Use of solar heat to increase air-cooled geothermal power plant performance during these periods can improve the correlation between power plant output and utility load curves. While solar energy is a renewable energy source with long term performance that can be accurately characterized, on shorter time scales of hours or days it can be highly intermittent. Concentrating solar power (CSP), aka solar-thermal, plants often incorporate thermal energy storage to ensure continued operation during cloud events or after sunset. Hybridization with a geothermal power plant can eliminate the need for thermal storage due to the constant availability of geothermal heat. In addition to the elimination of the requirement for solar thermal storage, the ability of a geothermal/solar-thermal hybrid plant to share a common power block can reduce capital costs relative to separate, stand-alone geothermal and solar-thermal power plant installations. The common occurrence of long-term geothermal resource productivity decline provides additional motivation to consider the use of hybrid power plants in geothermal power production. Geothermal resource productivity decline is a source of significant risk in geothermal power generation. Many, if not all, geothermal

Typical calculation and analysis of carbon emissions in thermal power plants

NASA Astrophysics Data System (ADS)

Gai, Zhi-jie; Zhao, Jian-gang; Zhang, Gang

2018-03-01

On December 19, 2017, the national development and reform commission issued the national carbon emissions trading market construction plan (power generation industry), which officially launched the construction process of the carbon emissions trading market. The plan promotes a phased advance in carbon market construction, taking the power industry with a large carbon footprint as a breakthrough, so it is extremely urgent for power generation plants to master their carbon emissions. Taking a coal power plant as an example, the paper introduces the calculation process of carbon emissions, and comes to the fuel activity level, fuel emissions factor and carbon emissions data of the power plant. Power plants can master their carbon emissions according to this paper, increase knowledge in the field of carbon reserves, and make the plant be familiar with calculation method based on the power industry carbon emissions data, which can help power plants positioning accurately in the upcoming carbon emissions trading market.

The optimization air separation plants for combined cycle MHD-power plant applications

NASA Technical Reports Server (NTRS)

Juhasz, A. J.; Springmann, H.; Greenberg, R.

1980-01-01

Some of the design approaches being employed during a current supported study directed at developing an improved air separation process for the production of oxygen enriched air for magnetohydrodynamics (MHD) combustion are outlined. The ultimate objective is to arrive at conceptual designs of air separation plants, optimized for minimum specific power consumption and capital investment costs, for integration with MHD combined cycle power plants.

Nuclear Security for Floating Nuclear Power Plants

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

Skiba, James M.; Scherer, Carolynn P.

2015-10-13

Recently there has been a lot of interest in small modular reactors. A specific type of these small modular reactors (SMR,) are marine based power plants called floating nuclear power plants (FNPP). These FNPPs are typically built by countries with extensive knowledge of nuclear energy, such as Russia, France, China and the US. These FNPPs are built in one country and then sent to countries in need of power and/or seawater desalination. Fifteen countries have expressed interest in acquiring such power stations. Some designs for such power stations are briefly summarized. Several different avenues for cooperation in FNPP technology aremore » proposed, including IAEA nuclear security (i.e. safeguards), multilateral or bilateral agreements, and working with Russian design that incorporates nuclear safeguards for IAEA inspections in non-nuclear weapons states« less

Consequences of hydraulic trait coordination and their associated uncertainties for tropical forest function

NASA Astrophysics Data System (ADS)

Christoffersen, B. O.; Xu, C.; Koven, C.; Fisher, R.; Knox, R. G.; Kueppers, L. M.; Chambers, J. Q.; McDowell, N.

2017-12-01

Recent syntheses of variation in woody plant traits have emphasized how hydraulic traits - those related to the acquisition, transport and retention of water across roots, stems and leaves - are coordinated along a limited set of dimensions or sequence of responses (Reich 2014, Bartlett et al. 2016). However, in many hydraulic trait-trait relationships, there is considerable residual variation, despite the fact that many bivariate relationships are statistically significant. In other instances, such as the relationship between root-stem-leaf vulnerability to embolism, data are so limited that testing the trait coordination hypothesis is not yet possible. The impacts on plant hydraulic function of competing hypotheses regarding trait coordination (or the lack thereof) and residual trait variation have not yet been comprehensively tested and thus remain unknown. We addressed this knowledge gap with a parameter sensitivity analysis using a plant hydraulics model in which all parameters are biologically-interpretable and measurable plant hydraulic traits, as embedded within a size- and demographically-structured ecosystem model, the `Functionally Assembled Terrestrial Ecosystem Simulator' (FATES). We focused on tropical forests, where co-existing species have been observed to possess large variability in their hydraulic traits. Assembling 10 distinct datasets of hydraulic traits of stomata, leaves, stems, and roots, we determined the best-fit theoretical distribution for each trait and quantified interspecific (between-species) trait-trait coordination in tropical forests as a rank correlation matrix. We imputed missing correlations with values based on competing hypotheses of trait coordination, such as coordinated shifts in embolism vulnerability from roots to shoots (the hydraulic fuse hypothesis). Based on the Fourier Amplitude Sensitivity Test and our correlation matrix, we generated thousands of parameter sets for an ensemble of hydraulics model simulations at a

Risk in nuclear power plants due to natural hazard phenomena

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

Lu, S.C.

1995-12-01

For the safety of nuclear power plants, it is important to identify potential areas of vulnerabilities to internal as well as external events to which nuclear power plants are exposed. This paper summarizes the risk in nuclear power plants due to natural hazard phenomena such as earthquakes, winds and tornadoes, floods, etc. The reported results are based on a limited number of probabilistic risk assessments (PRAS) performed for a few of the operating nuclear power plants within the United States. The summary includes an importance ranking of various natural hazard phenomena based on their contribution to the plant risk alongmore » with insights observed from the PRA studies.« less

NUCLEAR POWER PLANT

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

Preece, G.E.; Bell, F.R.

1963-06-26

A protective arrangement is designed for shielding the environment and for preventing the leakage of radioactive gases from a ship nuclear power plant. In this arrangement, the core has inner and outer pressure vessels and a biological shielding around the outer pressure vessel. The shielding comprises a series of steel cylindrical shells immersed in water, and its inner wall may comprise part of the outer pressure vessel. (D.L.C.)

4. NORTH ELEVATION OF POWER PLANT LOOKING SOUTH SOUTHWEST. ...

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

4. NORTH ELEVATION OF POWER PLANT LOOKING SOUTH SOUTHWEST. - Potomac Power Plant, On West Virginia Shore of Potomac River, about 1 mile upriver from confluence with Shenandoah River, Harpers Ferry, Jefferson County, WV

11. EAST WALL OF POWER PLANT BUILDING LOOKING WEST. ...

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

11. EAST WALL OF POWER PLANT BUILDING LOOKING WEST. - Potomac Power Plant, On West Virginia Shore of Potomac River, about 1 mile upriver from confluence with Shenandoah River, Harpers Ferry, Jefferson County, WV

JPL - Small Power Systems Applications Project. [for solar thermal power plant development and commercialization

NASA Technical Reports Server (NTRS)

Ferber, R. R.; Marriott, A. T.; Truscello, V.

1978-01-01

The Small Power Systems Applications (SPSA) Project has been established to develop and commercialize small solar thermal power plants. The technologies of interest include all distributed and central receiver technologies which are potentially economically viable in power plant sizes of one to 10 MWe. The paper presents an overview of the SPSA Project and briefly discusses electric utility involvement in the Project.

Scanning thermal plumes. [from power plant condensers

NASA Technical Reports Server (NTRS)

Scarpace, F. L.; Madding, R. P.; Green, T., III

1974-01-01

In order to study the behavior and effects of thermal plumes associated with the condenser cooling of power plants, thermal line scans are periodically made from aircraft over all power plants along the Wisconsin shore of Lake Michigan. Simultaneous ground truth is also gathered with a radiometer. Some sequential imagery has been obtained for periods up to two hours to study short term variations in the surface temperature of the plume. The article concentrates on the techniques used to analyze thermal scanner data for a single power plant which was studied intensively. The calibration methods, temperature dependence of the thermal scanner, and calculation of the modulation transfer function for the scanner are treated. It is concluded that obtaining quantitative surface-temperature data from thermal scanning is a nontrivial task. Accuracies up to plus or minus 0.1 C are attainable.

35. SOUTH PLANT NORTHCENTER RAILROAD SPUR, SHOWING POWER PLANT (BUILDINGS ...

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

35. SOUTH PLANT NORTH-CENTER RAILROAD SPUR, SHOWING POWER PLANT (BUILDINGS 325 AND 321) AT LEFT, FUEL TOWER AT CENTER AND CHLORINE EVAPORATOR (BUILDING 251) AT RIGHT. VIEW TO WEST - Rocky Mountain Arsenal, Bounded by Ninety-sixth Avenue & Fifty-sixth Avenue, Buckley Road, Quebec Street & Colorado Highway 2, Commerce City, Adams County, CO

Pilot solar power plant

NASA Astrophysics Data System (ADS)

Wolf, D.

A fully functionally efficient solar-thermal power plant (10 kW electric) was built. The operating principle of thermomechanical conversion of solar energy into mechanical or electrical energy is presented. The equipment is completely automatic. Flat plate collectors absorb solar energy and convert it into heat which is transmitted by water to a heat exchanger. A closed cycle machine uses the heat to boil a working fluid (C2C12F4). A screw, powered by gas expansion in the working fluid, converts mechanical energy into electrical energy.

Performance Assessment of Flashed Steam Geothermal Power Plant

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

Alt, Theodore E.

1980-12-01

Five years of operating experience at the Comision Federal de Electricidad (CFE) Cerro Prieto flashed steam geothermal power plant are evaluated from the perspective of U. S. utility operations. We focus on the design and maintenance of the power plant that led to the achievement of high plant capacity factors for Units No. 1 and 2 since commercial operation began in 1973. For this study, plant capacity factor is the ratio of the average load on the machines or equipment for the period of time considered to the capacity rating of the machines or equipment. The plant capacity factor ismore » the annual gross output in GWh compared to 657 GWh (2 x 37.5 MW x 8760 h). The CFE operates Cerro Prieto at base load consistent with the system connected electrical demand of the Baja California Division. The plant output was curtailed during the winter months of 1973-1975 when the system electric demand was less than the combined output capability of Cerro Prieto and the fossil fuel plant near Tijuana. Each year the system electric demand has increased and the Cerro Prieto units now operate at full load all the time. The CFE added Units 3 and 4 to Cerro Prieto in 1979 which increased the plant name plate capacity to 150 MW. Part of this additional capacity will supply power to San Diego Gas and Electric Company through an interconnection across the border. The achievement of a high capacity factor over an extensive operating period was influenced by operation, design, and maintenance of the geothermal flash steam power plant.« less

How do trees die? A test of the hydraulic failure and carbon starvation hypotheses

PubMed Central

Sevanto, Sanna; Mcdowell, Nate G; Dickman, L Turin; Pangle, Robert; Pockman, William T

2014-01-01

Despite decades of research on plant drought tolerance, the physiological mechanisms by which trees succumb to drought are still under debate. We report results from an experiment designed to separate and test the current leading hypotheses of tree mortality. We show that piñon pine (Pinus edulis) trees can die of both hydraulic failure and carbon starvation, and that during drought, the loss of conductivity and carbohydrate reserves can also co-occur. Hydraulic constraints on plant carbohydrate use determined survival time: turgor loss in the phloem limited access to carbohydrate reserves, but hydraulic control of respiration prolonged survival. Our data also demonstrate that hydraulic failure may be associated with loss of adequate tissue carbohydrate content required for osmoregulation, which then promotes failure to maintain hydraulic integrity. PMID:23730972

Numerical modelling of series-parallel cooling systems in power plant

NASA Astrophysics Data System (ADS)

Regucki, Paweł; Lewkowicz, Marek; Kucięba, Małgorzata

2017-11-01

The paper presents a mathematical model allowing one to study series-parallel hydraulic systems like, e.g., the cooling system of a power boiler's auxiliary devices or a closed cooling system including condensers and cooling towers. The analytical approach is based on a set of non-linear algebraic equations solved using numerical techniques. As a result of the iterative process, a set of volumetric flow rates of water through all the branches of the investigated hydraulic system is obtained. The calculations indicate the influence of changes in the pipeline's geometrical parameters on the total cooling water flow rate in the analysed installation. Such an approach makes it possible to analyse different variants of the modernization of the studied systems, as well as allowing for the indication of its critical elements. Basing on these results, an investor can choose the optimal variant of the reconstruction of the installation from the economic point of view. As examples of such a calculation, two hydraulic installations are described. One is a boiler auxiliary cooling installation including two screw ash coolers. The other is a closed cooling system consisting of cooling towers and condensers.

Fertilization with urea, ammonium and nitrate produce different effects on growth, hydraulic traits and drought tolerance in Pinus taeda seedlings.

PubMed

Faustino, Laura I; Moretti, Ana P; Graciano, Corina

2015-10-01

Urea fertilization decreases Pinus taeda L. growth in clay soils of subtropical areas. The negative effect of urea is related to changes in some hydraulic traits, similar to those observed in plants growing under drought. The aims of this work were (i) to determine whether different sources of nitrogen applied as fertilizers produce similar changes in growth and hydraulic traits to those observed by urea fertilization and (ii) to analyze the impact of those changes in plant drought tolerance. Plants fertilized with urea, nitrate [Formula: see text] or ammonium [Formula: see text] were grown well watered or with reduced water supply. Urea and [Formula: see text] fertilization reduced plant growth and increased root hydraulic conductance scaled by root dry weight (DW). [Formula: see text] fertilization did not reduce plant growth and increased shoot hydraulic conductance and stem hydraulic conductivity. We conclude that [Formula: see text] is the ion involved in the changes linked to the negative effect of urea fertilization on P. taeda growth. [Formula: see text] fertilization does not change drought susceptibility and it produces changes in shoot hydraulic traits, therefore plants avoid the depressive effect of fertilization. Urea and [Formula: see text] fertilizers induce changes in DW and root hydraulic conductance and consequently plants are less affected by drought. © The Author 2015. Published by Oxford University Press. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

Peach Bottom and Vermont Yankee Nuclear Power Plants

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

NONE

1992-12-31

A dramatic and extraordinary instance of state and local government control of nuclear power, the purchase by New York of the Shoreham plant is nonetheless indicative of the political demands that some states confront for additional involvement in the regulation of the radiological hazards associated with commercial nuclear power plants. Although the Supreme Court has appeared to expand, in the eight years since PG&E and Silkwood, the acceptable extent of state regulation, some states, in addition to New York, have acquired, with the acquiescence of the NRC, a degree of involvement that exceeds the role for state and local governmentsmore » provided by the Court. For example, the Commonwealth of Pennsylvania concluded with the Philadelphia Electric Company (PECO) in June 1989 an agreement that commits PECO to various initiatives, not otherwise required under NRC regulations, for the safe operation of the Peach Bottom nuclear power plant in Pennsylvania. In July 1991 the State of Vermont and Vermont Yankee Nuclear Power Corporation (Vermont Yankee) concluded an agreement similar to that concluded between Pennsylvania and PECO. The agreement also commits Vermont Yankee to certain initiatives, not otherwise required under NRC regulations, related to its operation of the Vermont Yankee nuclear power plant in Vermont. The agreement was precipitated by a challenge to an application, submitted to the NRC by Vermont Yankee in April 1989, to amend the Vermont Yankee plant license to extend its expiration date from December 11, 2007 to March 21, 2012. The amendment would allow the Vermont Yankee plant to operate for forty full years.« less

Monitoring Biological Activity at Geothermal Power Plants

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

Peter Pryfogle

2005-09-01

The economic impact of microbial growth in geothermal power plants has been estimated to be as high as $500,000 annually for a 100 MWe plant. Many methods are available to monitor biological activity at these facilities; however, very few plants have any on-line monitoring program in place. Metal coupon, selective culturing (MPN), total organic carbon (TOC), adenosine triphosphate (ATP), respirometry, phospholipid fatty acid (PLFA), and denaturing gradient gel electrophoresis (DGGE) characterizations have been conducted using water samples collected from geothermal plants located in California and Utah. In addition, the on-line performance of a commercial electrochemical monitor, the BIoGEORGE?, has beenmore » evaluated during extended deployments at geothermal facilities. This report provides a review of these techniques, presents data on their application from laboratory and field studies, and discusses their value in characterizing and monitoring biological activities at geothermal power plants.« less

Common mycorrhizal networks provide a potential pathway for the transfer of hydraulically lifted water between plants.

PubMed

Egerton-Warburton, Louise M; Querejeta, José Ignacio; Allen, Michael F

2007-01-01

Plant roots may be linked by shared or common mycorrhizal networks (CMNs) that constitute pathways for the transfer of resources among plants. The potential for water transfer by such networks was examined by manipulating CMNs independently of plant roots in order to isolate the role(s) of ectomycorrhizal (EM) and arbuscular mycorrhizal fungal (AMF) networks in the plant water balance during drought (soil water potential -5.9 MPa). Fluorescent tracer dyes and deuterium-enriched water were used to follow the pathways of water transfer from coastal live oak seedlings (Quercus agrifolia Nee; colonized by EM and AMF) conducting hydraulic lift (HL) into the roots of water-stressed seedlings connected only by EM (Q. agrifolia) or AMF networks (Q. agrifolia, Eriogonum fasciculatum Benth., Salvia mellifera Greene, Keckiella antirrhinoides Benth). When connected to donor plants by hyphal linkages, deuterium was detected in the transpiration flux of receiver oak plants, and dye-labelled extraradical hyphae, rhizomorphs, mantles, and Hartig nets were observed in receiver EM oak roots, and in AMF hyphae of Salvia. Hyphal labelling was scarce in Eriogonum and Keckiella since these species are less dependent on AMF. The observed patterns of dye distribution also indicated that only a small percentage of mycorrhizal roots and extraradical hyphae were involved with water transfer among plants. Our results suggest that the movement of water by CMNs is potentially important to plant survival during drought, and that the functional ecophysiological traits of individual mycorrhizal fungi may be a component of this mechanism.

Experience in connecting the power generating units of thermal power plants to automatic secondary frequency regulation within the united power system of Russia

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

Zhukov, A. V.; Komarov, A. N.; Safronov, A. N.

The principles of central control of the power generating units of thermal power plants by automatic secondary frequency and active power overcurrent regulation systems, and the algorithms for interactions between automatic power control systems for the power production units in thermal power plants and centralized systems for automatic frequency and power regulation, are discussed. The order of switching the power generating units of thermal power plants over to control by a centralized system for automatic frequency and power regulation and by the Central Coordinating System for automatic frequency and power regulation is presented. The results of full-scale system tests ofmore » the control of power generating units of the Kirishskaya, Stavropol, and Perm GRES (State Regional Electric Power Plants) by the Central Coordinating System for automatic frequency and power regulation at the United Power System of Russia on September 23-25, 2008, are reported.« less

Static and dynamic bending has minor effects on xylem hydraulics of conifer branches (Picea abies, Pinus sylvestris).

PubMed

Mayr, Stefan; Bertel, Clara; Dämon, Birgit; Beikircher, Barbara

2014-09-01

The xylem hydraulic efficiency and safety is usually measured on mechanically unstressed samples, although trees may be exposed to combined hydraulic and mechanical stress in the field. We analysed changes in hydraulic conductivity and vulnerability to drought-induced embolism during static bending of Picea abies and Pinus sylvestris branches as well as the effect of dynamic bending on the vulnerability. We hypothesized this mechanical stress to substantially impair xylem hydraulics. Intense static bending caused an only small decrease in hydraulic conductance (-19.5 ± 2.4% in P. abies) but no shift in vulnerability thresholds. Dynamic bending caused a 0.4 and 0.8 MPa decrease of the water potential at 50 and 88% loss of conductivity in P. sylvestris, but did not affect vulnerability thresholds in P. abies. With respect to applied extreme bending radii, effects on plant hydraulics were surprisingly small and are thus probably of minor eco-physiological importance. More importantly, results indicate that available xylem hydraulic analyses (of conifers) sufficiently reflect plant hydraulics under field conditions. © 2014 The Authors. Plant, Cell & Environment published by John Wiley & Sons Ltd.

Coal-Fired Power Plant Heat Rate Reductions

EPA Pesticide Factsheets

View a report that identifies systems and equipment in coal-fired power plants where efficiency improvements can be realized, and provides estimates of the resulting net plant heat rate reductions and costs for implementation.

Cavitation resistance and seasonal hydraulics differ among three arid Californian plant communities.

PubMed

Jacobsen, Anna L; Pratt, R Brandon; Davis, Stephen D; Ewers, Frank W

2007-12-01

Vulnerability to water stress-induced cavitation was measured on 27 woody shrub species from three arid plant communities including chaparral, coastal sage and Mojave Desert scrub. Dry season native embolism and pre-dawn water potential, and both wet and dry season xylem specific hydraulic conductivity (Ks) were measured. Cavitation resistance, estimated as water potential at 50% loss in conductivity (Psi50), was measured on all species during the wet season and on a subset of species during the dry season. Cavitation resistance varied with sampling season, with 8 of 13 sampled species displaying significant seasonal shifts. Native embolism and water potential were useful in identification of species displaying seasonal shifts. The Ks was not different among sites or seasons. The Psi50 varied among species and communities. Within communities, interspecific variation may be partially explained by differences in rooting depth or leaf habit (evergreen, semi-deciduous, deciduous). Communities diverged in their Psi50 with chaparral species displaying the greatest cavitation resistance regardless of sampling season. The greater cavitation resistance of chaparral species is surprising, considering the greater aridity of the Mojave Desert site. Adaptation to arid environments is due to many plant traits, and aridity does not necessarily lead to convergence in cavitation resistance.

The 25 kWe solar thermal Stirling hydraulic engine system: Conceptual design

NASA Technical Reports Server (NTRS)

White, Maurice; Emigh, Grant; Noble, Jack; Riggle, Peter; Sorenson, Torvald

1988-01-01

The conceptual design and analysis of a solar thermal free-piston Stirling hydraulic engine system designed to deliver 25 kWe when coupled to a 11 meter test bed concentrator is documented. A manufacturing cost assessment for 10,000 units per year was made. The design meets all program objectives including a 60,000 hr design life, dynamic balancing, fully automated control, more than 33.3 percent overall system efficiency, properly conditioned power, maximum utilization of annualized insolation, and projected production costs. The system incorporates a simple, rugged, reliable pool boiler reflux heat pipe to transfer heat from the solar receiver to the Stirling engine. The free-piston engine produces high pressure hydraulic flow which powers a commercial hydraulic motor that, in turn, drives a commercial rotary induction generator. The Stirling hydraulic engine uses hermetic bellows seals to separate helium working gas from hydraulic fluid which provides hydrodynamic lubrication to all moving parts. Maximum utilization of highly refined, field proven commercial components for electric power generation minimizes development cost and risk.

Rapporteur report: MHD electric power plants

NASA Technical Reports Server (NTRS)

Seikel, G. R.

1980-01-01

Five US papers from the Proceedings of the Seventh International Conference on MHD Electrical Power Generation at the Massachusetts Institute of Technology are summarized. Results of the initial parametric phase of the US effort on the study of potential early commercial MHD plants are reported and aspects of the smaller commercial prototype plant termed the Engineering Test Facility are discussed. The alternative of using a disk geometry generator rather than a linear generator in baseload MHD plants is examined. Closed-cycle as well as open-cycle MHD plants are considered.

Power Plant Water Intake Assessment.

ERIC Educational Resources Information Center

Zeitoun, Ibrahim H.; And Others

1980-01-01

In order to adequately assess the impact of power plant cooling water intake on an aquatic ecosystem, total ecosystem effects must be considered, rather than merely numbers of impinged or entrained organisms. (Author/RE)

NUCLEAR POWER PLANTS

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

Bell, F.R.

1962-12-01

A power plant is described that comprises a nuclear reactor and a heat exchanger which is included in primary and secondary circuits. Fluid in the primary circuit extracts heat from the reactor and transfers it in the heat exchanger to the fluid in the secondary circuit which transmits energy to one or more utilization points. Means are provided for detecting, isolating, and removing radioactive fluid from the secondary circuit. (R.J.S.)

A simulated field trip: "The visual aspects of power plant sitings"

Treesearch

Bill Bottomly; Alex Young

1979-01-01

The growth of our economy is demanding construction of a variety of power plants to generate electricity which is having a significant impact on the visual environment. These power plants will consist of conventional thermal (fossil fuel and nuclear), geothermal, wind and solar power plants. There are several areas where solutions to the visual impacts of these power...

76 FR 46856 - Qualification of Connection Assemblies for Nuclear Power Plants

Federal Register 2010, 2011, 2012, 2013, 2014

2011-08-03

... Power Plants AGENCY: Nuclear Regulatory Commission. ACTION: Regulatory guide; issuance. SUMMARY: The U.S..., ``Qualification of Connection Assemblies for Nuclear Power Plants.'' This guide describes a method that the NRC... in nuclear power plants. The environmental qualification helps ensure that connection assemblies can...

INDEPENDENT POWER PLANT USING WOOD WASTE

EPA Science Inventory

A 1 MWe power plant using waste wood is to be installed at a U.S. Marine Corps base, which will supply all the wood for the plant from a landfill site. The core energy conversion technology is a down-draft gasifier supplying approximately 150 Btu/scf gas to both spark ignition an...

16. Photocopy of a photograph1921 EASTSIDE POWER PLANT LOOKING NORTH ...

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

16. Photocopy of a photograph--1921 EASTSIDE POWER PLANT LOOKING NORTH - American Falls Water, Power & Light Company, Island Power Plant, Snake River, below American Falls Dam, American Falls, Power County, ID

Visual sensitivity of river recreation to power plants

Treesearch

David H. Blau; Michael C. Bowie

1979-01-01

The consultants were asked by the Power Plant Siting Staff of the Minnesota Environmental Quality Council to develop a methodology for evaluating the sensitivity of river-related recreational activities to visual intrusion by large coal-fired power plants. The methodology, which is applicable to any major stream in the state, was developed and tested on a case study...

Nuclear Power Plant Simulation Game.

ERIC Educational Resources Information Center

Weiss, Fran

1979-01-01

Presents a nuclear power plant simulation game which is designed to involve a class of 30 junior or senior high school students. Scientific, ecological, and social issues covered in the game are also presented. (HM)

Effects of hydraulic pressure on the performance of single chamber air-cathode microbial fuel cells.

PubMed

Cheng, Shaoan; Liu, Weifeng; Guo, Jian; Sun, Dan; Pan, Bin; Ye, Yaoli; Ding, Weijun; Huang, Haobin; Li, Fujian

2014-06-15

Scaling up of microbial fuel cells (MFCs) without losing power density requires a thorough understanding of the effect of hydraulic pressure on MFC performance. In this work, the performance of an activated carbon air-cathode MFC was evaluated under different hydraulic pressures. The MFC under 100 mmH2O hydraulic pressure produced a maximum power density of 1260 ± 24 mW m(-2), while the power density decreased by 24.4% and 44.7% as the hydraulic pressure increased to 500 mmH2O and 2000 mmH2O, respectively. Notably, the performance of both the anode and the cathode had decreased under high hydraulic pressures. Electrochemical impedance spectroscopy tests of the cathode indicated that both charge transfer resistance and diffusion transfer resistance increased with the increase in hydraulic pressure. Denaturing gradient gel electrophoresis of PCR-amplified partial 16S rRNA genes demonstrated that the similarity among anodic biofilm communities under different hydraulic pressures was ≥ 90%, and the communities of all MFCs were dominated by Geobacter sp. These results suggested that the reduction in power output of the single chamber air-cathode MFC under high hydraulic pressures can be attributed to water flooding of the cathode and suppression the metabolism of anodic exoelectrogenic bacteria. Copyright © 2014 Elsevier B.V. All rights reserved.

Intraspecific differences in drought tolerance and acclimation in hydraulics of Ligustrum vulgare and Viburnum lantana.

PubMed

Beikircher, Barbara; Mayr, Stefan

2009-06-01

An adequate general drought tolerance and the ability to acclimate to changing hydraulic conditions are important features for long-lived woody plants. In this study, we compared hydraulic safety (water potential at 50% loss of conductivity, Psi(50)), hydraulic efficiency (specific conductivity, k(s)), xylem anatomy (mean tracheid diameter, d(mean), mean hydraulic diameter, d(h), conduit wall thickness, t, conduit wall reinforcement, (t/b)(h)(2)) and stomatal conductance, g(s), of forest plants as well as irrigated and drought-treated garden plants of Ligustrum vulgare L. and Viburnum lantana L. Forest plants of L. vulgare and V. lantana were significantly less resistant to drought-induced cavitation (Psi(50) at -2.82 +/- 0.13 MPa and -2.79 +/- 0.17 MPa) than drought-treated garden plants (- 4.58 +/- 0.26 MPa and -3.57 +/- 0.15 MPa). When previously irrigated garden plants were subjected to drought, a significant decrease in d(mean) and d(h) and an increase in t and (t/b)(h)(2) were observed in L. vulgare. In contrast, in V. lantana conduit diameters increased significantly but no change in t and (t/b)(h)(2) was found. Stomatal closure occurred at similar water potentials (Psi(sc)) in forest plants and drought-treated garden plants, leading to higher safety margins (Psi(sc) - Psi(50)) of the latter (L. vulgare 1.63 MPa and V. lantana 0.43 MPa). These plants also showed higher g(s) at moderate Psi, more abrupt stomatal closure and lower cuticular conductivity. Data indicate that the development of drought-tolerant xylem as well as stomatal regulation play an important role in drought acclimation, whereby structural and physiological responses to drought are species-specific and depend on the plant's hydraulic strategy.

Water treatment plants assessment at Talkha power plant.

PubMed

El-Sebaie, Olfat D; Abd El-Kerim, Ghazy E; Ramadan, Mohamed H; Abd El-Atey, Magda M; Taha, Sahr Ahmed

2002-01-01

Talkha power plant is the only power plant located in El-Mansoura. It generates electricity using two different methods by steam turbine and gas turbine. Both plants drew water from River Nile (208 m3 /h). The Nile raw water passes through different treatment processes to be suitable for drinking and operational uses. At Talkha power plant, there are two purification plants used for drinking water supply (100 m3/h) and for water demineralization supply (108 m3/h). This study aimed at studying the efficiency of the water purification plants. For drinking water purification plant, the annual River Nile water characterized by slightly alkaline pH (7.4-8), high annual mean values of turbidity (10.06 NTU), Standard Plate Count (SPC) (313.3 CFU/1 ml), total coliform (2717/100 ml), fecal coliform (0-2400/100 ml), and total algae (3 x 10(4) org/I). The dominant group of algae all over the study period was green algae. The blue green algae was abundant in Summer and Autumn seasons. The pH range, and the annual mean values of turbidity, TDS, total hardness, sulfates, chlorides, nitrates, nitrites, fluoride, and residual chlorine for purified water were in compliance with Egyptian drinking water standards. All the SPC recorded values with an annual mean value of 10.13 CFU/1 ml indicated that chlorine dose and contact time were not enough to kill the bacteria. However, they were in compliance with Egyptian decree (should not exceed 50 CFU/1 ml). Although the removal efficiency of the plant for total coliform and blue green algae was high (98.5% and 99.2%, respectively), the limits of the obtained results with an annual mean values of 40/100 ml and 15.6 org/l were not in compliance with the Egyptian decree (should be free from total coliform, fecal coliform and blue green algae). For water demineralization treatment plant, the raw water was characterized by slightly alkaline pH. The annual mean values of conductivity, turbidity, and TDS were 354.6 microS/cm, 10.84 NTU, and 214

Design and implementation of a simple nuclear power plant simulator

NASA Astrophysics Data System (ADS)

Miller, William H.

1983-02-01

A simple PWR nuclear power plant simulator has been designed and implemented on a minicomputer system. The system is intended for students use in understanding the power operation of a nuclear power plant. A PDP-11 minicomputer calculates reactor parameters in real time, uses a graphics terminal to display the results and a keyboard and joystick for control functions. Plant parameters calculated by the model include the core reactivity (based upon control rod positions, soluble boron concentration and reactivity feedback effects), the total core power, the axial core power distribution, the temperature and pressure in the primary and secondary coolant loops, etc.

Flexibility of CCS Power Plants and Transport Systems

NASA Astrophysics Data System (ADS)

Nimtz, Michael; Krautz, Hans-Joachim

2013-04-01

Growing shares of renewable energy in the German power grid urge fossil fuelled power plants to reduce load or to shut down completely with increasing frequency and amplitude. Shut down, load changes and the following restart or ramp-up often have to be carried out as fast as possible. To realize such fast transitions is already complicated and expensive for conventional power plants - if further measures for CO2 reduction are applied, the task is even harder. Capture equipment and transport systems will add further process steps as well as additional masses of fluids and construction material. This will result in a change of time constants and a generally slower system reaction on changes in parameters like load, temperature and pressure in the power plant components and capture units. On the other hand there is only limited time to earn money by selling electricity - if there is a chance to sell more electricity in a short term, efficiencies should be as high as possible. Any capture unit that would reduce the efficiency causes economic conflicts. Therefore measures are analysed to offset the power generation from the capture process in time or to reduce the capture load temporarily. The poster will present a case study for different CCS power plant configurations and load scenarios representing typical grid load from renewable energies. Approaches to balance the load and/or the CO2 output of these power plants will be presented. These approaches comprise: bypassing of flue gas, intermediate storage of heat and/or fluids. Amounts of additional steam, electrical energy and other process fluids (e.g. scrubbing fluids like MEA) and size of auxiliary equipment will be shown .Finally, effects on the transport system (e.g. cooling down of CO2 in the pipeline and changes in mass and volume flow) will be presented and discussed.

NREL/PG&E Condensation System Increases Geothermal Power Plant Efficiency

Science.gov Websites

. Geothermal power plants like The Geysers produce energy by collecting steam from underground reservoirs and NREL/PG&E Condensation System Increases Geothermal Power Plant Efficiency For more information world's largest producer of geothermal power has improved its power production efficiency thanks to a new

Environmental impact assessment of coal power plants in operation

NASA Astrophysics Data System (ADS)

Bartan, Ayfer; Kucukali, Serhat; Ar, Irfan

2017-11-01

Coal power plants constitute an important component of the energy mix in many countries. However, coal power plants can cause several environmental risks such as: climate change and biodiversity loss. In this study, a tool has been proposed to calculate the environmental impact of a coal-fired thermal power plant in operation by using multi-criteria scoring and fuzzy logic method. We take into account the following environmental parameters in our tool: CO, SO2, NOx, particulate matter, fly ash, bottom ash, the cooling water intake impact on aquatic biota, and the thermal pollution. In the proposed tool, the boundaries of the fuzzy logic membership functions were established taking into account the threshold values of the environmental parameters which were defined in the environmental legislation. Scoring of these environmental parameters were done with the statistical analysis of the environmental monitoring data of the power plant and by using the documented evidences that were obtained during the site visits. The proposed method estimates each environmental impact factor level separately and then aggregates them by calculating the Environmental Impact Score (EIS). The proposed method uses environmental monitoring data and documented evidence instead of using simulation models. The proposed method has been applied to the 4 coal-fired power plants that have been operation in Turkey. The Environmental Impact Score was obtained for each power plant and their environmental performances were compared. It is expected that those environmental impact assessments will contribute to the decision-making process for environmental investments to those plants. The main advantage of the proposed method is its flexibility and ease of use.

76 FR 66089 - Access Authorization Program for Nuclear Power Plants

Federal Register 2010, 2011, 2012, 2013, 2014

2011-10-25

... NUCLEAR REGULATORY COMMISSION [NRC-2011-0245] Access Authorization Program for Nuclear Power... Program for Nuclear Power Plants.'' This guide describes a method that NRC staff considers acceptable to... Regulations (10 CFR), section 73.56, ``Personnel Access Authorization Requirements for Nuclear Power Plants...

Carbonated Science Cleans Power Plants

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

Rousseau, Roger; Heldebrant, David; Glezakou, Vand

Similar to the properties of soda, liquid solvents can efficiently capture and convert carbon dioxide from coal power plants. Researchers at PNNL explain this process and how this method can turn captured carbon into plastic or fuel.

A study on economic power dispatch grid connected PV power plant in educational institutes

NASA Astrophysics Data System (ADS)

Singh, Kuldip; Kumar, M. Narendra; Mishra, Satyasis

2018-04-01

India has main concerns on environment and escalation of fuel prices with respect to diminution of fossil fuel reserves and the major focus on renewable Energy sources for power generation to fulfill the present and future energy demand. Installation of PV power plants in the Educational Institutions has grown up drastically throughout India. More PV power plant are integrated with load and grid through net metering. Therefore, this paper is an analysis of the 75kWp PV plant at chosen buses, considering the need of minimum demand from the grid. The case study is carried out for different generation level throughout the day and year w.r.t load and climate changes, load sharing on grid. The economic dispatch model developed for PV plant integrated with Grid.

The relationship between reference canopy conductance and simplified hydraulic architecture

NASA Astrophysics Data System (ADS)

Novick, Kimberly; Oren, Ram; Stoy, Paul; Juang, Jehn-Yih; Siqueira, Mario; Katul, Gabriel

2009-06-01

Terrestrial ecosystems are dominated by vascular plants that form a mosaic of hydraulic conduits to water movement from the soil to the atmosphere. Together with canopy leaf area, canopy stomatal conductance regulates plant water use and thereby photosynthesis and growth. Although stomatal conductance is coordinated with plant hydraulic conductance, governing relationships across species has not yet been formulated at a practical level that can be employed in large-scale models. Here, combinations of published conductance measurements obtained with several methodologies across boreal to tropical climates were used to explore relationships between canopy conductance rates and hydraulic constraints. A parsimonious hydraulic model requiring sapwood-to-leaf area ratio and canopy height generated acceptable agreement with measurements across a range of biomes (r2=0.75). The results suggest that, at long time scales, the functional convergence among ecosystems in the relationship between water-use and hydraulic architecture eclipses inter-specific variation in physiology and anatomy of the transport system. Prognostic applicability of this model requires independent knowledge of sapwood-to-leaf area. In this study, we did not find a strong relationship between sapwood-to-leaf area and physical or climatic variables that are readily determinable at coarse scales, though the results suggest that climate may have a mediating influence on the relationship between sapwood-to-leaf area and height. Within temperate forests, canopy height alone explained a large amount of the variance in reference canopy conductance (r2=0.68) and this relationship may be more immediately applicable in the terrestrial ecosystem models.

Ocean thermal gradient as a generator of electricity. OTEC power plant

NASA Astrophysics Data System (ADS)

Enrique, Luna-Gomez Victor; Angel, Alatorre-Mendieta Miguel

2016-04-01

The OTEC (Ocean Thermal Energy Conversion) is a power plant that uses the thermal gradient of the sea water between the surface and a depth of about 700 meters. It works by supplying the heat to a steam machine, for evaporation, with sea water from the surface and cold, to condense the steam, with deep sea water. The energy generated by the power plant OTEC can be transferred to the electric power grid, another use is to desalinate seawater. During the twentieth century in some countries experimental power plants to produce electricity or obtaining drinking water they were installed. On the Mexico's coast itself this thermal gradient, as it is located in tropical seas it occurs, so it has possibilities of installing OTEC power plant type. In this paper one type OTEC power plant operation is represented in most of its components.

Evidence for Hydraulic Vulnerability Segmentation and Lack of Xylem Refilling under Tension.

PubMed

Charrier, Guillaume; Torres-Ruiz, José M; Badel, Eric; Burlett, Regis; Choat, Brendan; Cochard, Herve; Delmas, Chloe E L; Domec, Jean-Christophe; Jansen, Steven; King, Andrew; Lenoir, Nicolas; Martin-StPaul, Nicolas; Gambetta, Gregory Alan; Delzon, Sylvain

2016-11-01

The vascular system of grapevine (Vitis spp.) has been reported as being highly vulnerable, even though grapevine regularly experiences seasonal drought. Consequently, stomata would remain open below water potentials that would generate a high loss of stem hydraulic conductivity via xylem embolism. This situation would necessitate daily cycles of embolism repair to restore hydraulic function. However, a more parsimonious explanation is that some hydraulic techniques are prone to artifacts in species with long vessels, leading to the overestimation of vulnerability. The aim of this study was to provide an unbiased assessment of (1) the vulnerability to drought-induced embolism in perennial and annual organs and (2) the ability to refill embolized vessels in two Vitis species X-ray micro-computed tomography observations of intact plants indicated that both Vitis vinifera and Vitis riparia were relatively vulnerable, with the pressure inducing 50% loss of stem hydraulic conductivity = -1.7 and -1.3 MPa, respectively. In V. vinifera, both the stem and petiole had similar sigmoidal vulnerability curves but differed in pressure inducing 50% loss of hydraulic conductivity (-1.7 and -1 MPa for stem and petiole, respectively). Refilling was not observed as long as bulk xylem pressure remained negative (e.g. at the apical part of the plants; -0.11 ± 0.02 MPa) and change in percentage loss of conductivity was 0.02% ± 0.01%. However, positive xylem pressure was observed at the basal part of the plant (0.04 ± 0.01 MPa), leading to a recovery of conductance (change in percentage loss of conductivity = -0.24% ± 0.12%). Our findings provide evidence that grapevine is unable to repair embolized xylem vessels under negative pressure, but its hydraulic vulnerability segmentation provides significant protection of the perennial stem. © 2016 American Society of Plant Biologists. All Rights Reserved.

AERIAL PHOTOGRAPHY AND GROUND VERIFICATION AT POWER PLANT SITES: WISCONSIN POWER PLANT IMPACT STUDY

EPA Science Inventory

This study demonstrated and evaluated nine methods for monitoring the deterioration of a large wetland on the site of a newly-constructed coal-fired power plant in Columbia, County, Wisconsin. Four of the nine methods used data from ground sampling; two were remote sensing method...

AUTOMOTIVE DIESEL MAINTENANCE 2. UNIT IX, AUTOMATIC TRANSMISSIONS--HYDRAULIC SYSTEM (PART I).

ERIC Educational Resources Information Center

Human Engineering Inst., Cleveland, OH.

THIS MODULE OF A 25-MODULE COURSE IS DESIGNED TO DEVELOP AN UNDERSTANDING OF THE OIL FLOW WITHIN HYDRAULIC TRANSMISSIONS USED ON DIESEL POWERED VEHICLES. TOPICS ARE GENERAL DESCRIPTION, HYDRAULIC CIRCUITS, AND BRAKE HYDRAULIC CIRCUIT AND OPERATION. THE MODULE CONSISTS OF A SELF-INSTRUCTIONAL PROGRAMED TRAINING FILM "LEARNING ABOUT THE ALLISON…

More on duel purpose solar-electric power plants

NASA Astrophysics Data System (ADS)

Hall, F. F.

Rationale for such plants is reviewed and plant elements are listed. Dual purpose solar-electric plants would generate both electricity and hydrogen gas for conversion to ammonia or methanol or direct use as a fuel of unsurpassed specific power and cleanliness. By-product oxygen would also be sold to owners of hydrogen age equipment. Evolved gasses at high pressure could be fired in compressorless gas turbines, boilerless steam-turbines or fuel-cell-inverter hydrogen-electric power drives of high thermal efficiency as well as in conventional internal combustion engines.

Mechanisms of plant survival and mortality during drought: Why do some plants survive while others succumb to drought?

USGS Publications Warehouse

McDowell, Nate G.; Pockman, William T.; Allen, Craig D.; Breshears, David D.; Cobb, Neil; Kolb, Thomas; Plaut, Jennifer; Sperry, John; West, Adam; Williams, David G.; Yepez, Enrico A.

2008-01-01

Severe droughts have been associated with regional-scale forest mortality worldwide. Climate change is expected to exacerbate regional mortality events; however, prediction remains difficult because the physiological mechanisms underlying drought survival and mortality are poorly understood. We developed a hydraulically based theory considering carbon balance and insect resistance that allowed development and examination of hypotheses regarding survival and mortality. Multiple mechanisms may cause mortality during drought. A common mechanism for plants with isohydric regulation of water status results from avoidance of drought-induced hydraulic failure via stomatal closure, resulting in carbon starvation and a cascade of downstream effects such as reduced resistance to biotic agents. Mortality by hydraulic failure per se may occur for isohydric seedlings or trees near their maximum height. Although anisohydric plants are relatively drought-tolerant, they are predisposed to hydraulic failure because they operate with narrower hydraulic safety margins during drought. Elevated temperatures should exacerbate carbon starvation and hydraulic failure. Biotic agents may amplify and be amplified by drought-induced plant stress. Wet multidecadal climate oscillations may increase plant susceptibility to drought-induced mortality by stimulating shifts in hydraulic architecture, effectively predisposing plants to water stress. Climate warming and increased frequency of extreme events will probably cause increased regional mortality episodes. Isohydric and anisohydric water potential regulation may partition species between survival and mortality, and, as such, incorporating this hydraulic framework may be effective for modeling plant survival and mortality under future climate conditions.

Microprocessor-based control systems application in nuclear power plant critical systems

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

Shah, M.R.; Nowak, J.B.

Microprocessor-based control systems have been used in fossil power plants and are receiving greater acceptance for application in nuclear plants. This technology is not new but it does require unique considerations when applied to nuclear power plants. Sargent and Lundy (S and L) has used a microprocessor-based component logic control system (interposing Logic System) for safety- and non-safety-related components in nuclear power plants under construction overseas. Currently, S and L is in the design stage to replace an existing analog control system with a microprocessor-based control system in the U.S. The trend in the industry is to replace systems inmore » existing plants or design new power plants with microprocessor-based control systems.« less

Characteristics of Air Entrainment in Hydraulic Jump

NASA Astrophysics Data System (ADS)

Albarkani, M. S. S.; Tan, L. W.; Al-Gheethi, A.

2018-04-01

The characteristics of hydraulic jump, especially the air entrainment within jump is still not properly understood. Therefore, the current work aimed to determine the size and number of air entrainment formed in hydraulic jump at three different Froude numbers and to obtain the relationship between Froude number with the size and number of air entrainment in hydraulic jump. Experiments of hydraulic jump were conducted in a 10 m long and 0.3 m wide Armfield S6MKII glass-sided tilting flume. Hydraulic jumps were produced by flow under sluice gate with varying Froude number. The air entrainment of the hydraulic jump was captured with a Canon Power Shot SX40 HS digital camera in video format at 24 frames per second. Three discharges have been considered, i.e. 0.010 m3/s, 0.011 m3/s, and 0.013 m3/s. For hydraulic jump formed in each discharge, 32 frames were selected for the purpose of analysing the size and number of air entrainment in hydraulic jump. The results revealed that that there is a tendency to have greater range in sizes of air bubbles as Fr1 increases. Experiments with Fr1 = 7.547. 7.707, and 7.924 shown that the number of air bubbles increases exponentially with Fr1 at a relationship of N = 1.3814 e 0.9795Fr1.

75 FR 16520 - James A. Fitzpatrick Nuclear Power Plant; Exemption

Federal Register 2010, 2011, 2012, 2013, 2014

2010-04-01

... date for all operating nuclear power plants, but noted that the Commission's regulations provide... Power Plant; Exemption 1.0 Background Entergy Nuclear Operations, Inc. (the licensee) is the holder of Facility Operating License No. DPR-59, which authorizes operation of the James A. FitzPatrick Nuclear Power...

Water stress-induced modifications of leaf hydraulic architecture in sunflower: co-ordination with gas exchange.

PubMed

Nardini, Andrea; Salleo, Sebastiano

2005-12-01

The hydraulic architecture, water relationships, and gas exchange of leaves of sunflower plants, grown under different levels of water stress, were measured. Plants were either irrigated with tap water (controls) or with PEG600 solutions with osmotic potential of -0.4 and -0.8 MPa (PEG04 and PEG08 plants, respectively). Mature leaves were measured for hydraulic resistance (R(leaf)) before and after making several cuts across minor veins, thus getting the hydraulic resistance of the venation system (R(venation)). R(leaf) was nearly the same in controls and PEG04 plants but it was reduced by about 30% in PEG08 plants. On the contrary, R(venation) was lowest in controls and increased in PEG04 and PEG08 plants as a likely result of reduction in the diameter of the veins' conduits. As a consequence, the contribution of R(venation) to the overall R(leaf) markedly increased from controls to PEG08 plants. Leaf conductance to water vapour (g(L)) was highest in controls and significantly lower in PEG04 and PEG08 plants. Moreover, g(L) was correlated to R(venation) and to leaf water potential (psi(leaf)) with highly significant linear relationships. It is concluded that water stress has an important effect on the hydraulic construction of leaves. This, in turn, might prove to be a crucial factor in plant-water relationships and gas exchange under water stress conditions.

Phytomonitoring of air pollution around a thermal power plant

NASA Astrophysics Data System (ADS)

Agrawal, M.; Agrawal, S. B.

This study was undertaken in order to assess the impact of air pollutants on vegetation around Obra thermal power plant (1550 M W capacity) in the Mirzapur district of Uttar Pradesh. For this purpose, Mangifera indica, Citrus medico and Bouganvillaea spectabilis plants, most common at all sites, were selected as test plants. Five study sites were selected northeast (prevailing wind) of the thermal power plant. A control site was also selected at a distance of 30 km north of Obra. Responses of plants to pollutants in terms of presence of foliar injury symptoms and changes in chlorophyll, ascorbic acid and S content were measured. These changes were correlated with ambient SO 2 and suspended particulate matter (SPM) concentrations and the amount of dust settled on leaf surfaces. The SO 2 and SPM concentrations were quite high in the immediate vicinity of the power plant. There also exists a direct relationship between the concentration of SPM in air and amount of dust deposited on leaf surfaces. Maximum dust deposition was observed on M. indica plants. The levels of foliar injury, chlorophyll and ascorbic acid were found to decrease and that of S increase in plants around the power plant in comparison to those growing at a control site. The magnitude of such changes was maximum in M. indica and minimum in C. medica. A species specific direct relationship between the increase in the amount of S and decrease in chlorophyll content was observed. The study suggests that differential sensitivity of plants to SO 2 may be used in evaluating the air pollution impact around emission sources and M. indica plants can be used as an indicator plant for quantifying biological changes.

Intelligent Modeling for Nuclear Power Plant Accident Management

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

Darling, Michael Christropher; Luger, George F.; Jones, Thomas B.

This study explores the viability of using counterfactual reasoning for impact analyses when understanding and responding to “beyond-design-basis” nuclear power plant accidents. Currently, when a severe nuclear power plant accident occurs, plant operators rely on Severe Accident Management Guidelines. However, the current guidelines are limited in scope and depth: for certain types of accidents, plant operators would have to work to mitigate the damage with limited experience and guidance for the particular situation. We aim to fill the need for comprehensive accident support by using a dynamic Bayesian network to aid in the diagnosis of a nuclear reactor’s state andmore » to analyze the impact of possible response measures.« less

Intelligent Modeling for Nuclear Power Plant Accident Management

DOE PAGES

Darling, Michael Christropher; Luger, George F.; Jones, Thomas B.; ...

2018-03-29

This study explores the viability of using counterfactual reasoning for impact analyses when understanding and responding to “beyond-design-basis” nuclear power plant accidents. Currently, when a severe nuclear power plant accident occurs, plant operators rely on Severe Accident Management Guidelines. However, the current guidelines are limited in scope and depth: for certain types of accidents, plant operators would have to work to mitigate the damage with limited experience and guidance for the particular situation. We aim to fill the need for comprehensive accident support by using a dynamic Bayesian network to aid in the diagnosis of a nuclear reactor’s state andmore » to analyze the impact of possible response measures.« less

POWER PLANT COOLING WATER CHLORINATION IN NORTHERN CALIFORNIA

EPA Science Inventory

A survey was conducted of chlorination practices at five power plants owned and operated by the Pacific Gas and Electric Company. Frequency and duration of chlorination varied significantly from plant to plant and was controlled analytically by the orthotolidine and/or amperometr...

Stability assessment of the chemical composition of the treated mining water used to replenish the cooling circuit in Jaworzno III Power Plant - Power Plant II

NASA Astrophysics Data System (ADS)

Karpiński, Marcin; Kmiecik, Ewa

2017-11-01

In Poland, electricity is still produced mainly in conventional power plants where fuel and water are materials necessary to generate the electricity. Even in modern power plants operating according to the principles of the sustainable development, this involves a high intake of water and considerable production of wastewater. This, in turn, necessi-tates the application of some technological solutions aimed at limiting the negative impact on the environment. The Jaworzno III Power Plant - Power Plant II is located in Jaworzno, Silesian Province, Poland. In order to minimise the negative impact on the surface water, the plant replenishes the cooling circuit with the mining water obtained from the closed-down Jan Kanty mine. The paper presents a stability assessment of the chemical composition of the treated mining water used to replenish the cooling circuit based on the data from 2007-2017.

[Risk communication in construction of new nuclear power plant].

PubMed

He, Gui-Zhen; Lü, Yong-Long

2013-03-01

Accompanied by construction of new nuclear power plants in the coming decades in China, risk management has become increasingly politicized and contentious. Nuclear risk communication is a critical component in helping individuals prepare for, respond to, and recover from nuclear power emergencies. It was discussed that awareness of trust and public attitudes are important determinants in nuclear power risk communication and management. However, there is limited knowledge about how to best communicate with at-risk populations around nuclear power plant in China. To bridge this gap, this study presented the attitudinal data from a field survey in under-building Haiyang nuclear power plant, Shandong Province to measure public support for and opposition to the local construction of nuclear power plant. The paper discussed the structure of the communication process from a descriptive point of view, recognizing the importance of trust and understanding the information openness. The results showed that decision-making on nuclear power was dominated by a closed "iron nuclear triangle" of national governmental agencies, state-owned nuclear enterprises and scientific experts. Public participation and public access to information on nuclear constructions and assessments have been marginal and media was a key information source. As information on nuclear power and related risks is very restricted in China, Chinese citizens (51%) tend to choose the government as the most trustworthy source. More respondents took the negative attitudes toward nuclear power plant construction around home. It drew on studies about risk communication to develop some guidelines for successful risk communication. The conclusions have vast implications for how we approach risk management in the future. The findings should be of interest to state and local emergency managers, community-based organizations, public health researchers, and policy makers.

Development of an integrated thermal-hydraulics capability incorporating RELAP5 and PANTHER neutronics code

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

Page, R.; Jones, J.R.

1997-07-01

Ensuring that safety analysis needs are met in the future is likely to lead to the development of new codes and the further development of existing codes. It is therefore advantageous to define standards for data interfaces and to develop software interfacing techniques which can readily accommodate changes when they are made. Defining interface standards is beneficial but is necessarily restricted in application if future requirements are not known in detail. Code interfacing methods are of particular relevance with the move towards automatic grid frequency response operation where the integration of plant dynamic, core follow and fault study calculation toolsmore » is considered advantageous. This paper describes the background and features of a new code TALINK (Transient Analysis code LINKage program) used to provide a flexible interface to link the RELAP5 thermal hydraulics code with the PANTHER neutron kinetics and the SIBDYM whole plant dynamic modelling codes used by Nuclear Electric. The complete package enables the codes to be executed in parallel and provides an integrated whole plant thermal-hydraulics and neutron kinetics model. In addition the paper discusses the capabilities and pedigree of the component codes used to form the integrated transient analysis package and the details of the calculation of a postulated Sizewell `B` Loss of offsite power fault transient.« less

Low-Rank Coal Grinding Performance Versus Power Plant Performance

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

Rajive Ganguli; Sukumar Bandopadhyay

2008-12-31

The intent of this project was to demonstrate that Alaskan low-rank coal, which is high in volatile content, need not be ground as fine as bituminous coal (typically low in volatile content) for optimum combustion in power plants. The grind or particle size distribution (PSD), which is quantified by percentage of pulverized coal passing 74 microns (200 mesh), affects the pulverizer throughput in power plants. The finer the grind, the lower the throughput. For a power plant to maintain combustion levels, throughput needs to be high. The problem of particle size is compounded for Alaskan coal since it has amore » low Hardgrove grindability index (HGI); that is, it is difficult to grind. If the thesis of this project is demonstrated, then Alaskan coal need not be ground to the industry standard, thereby alleviating somewhat the low HGI issue (and, hopefully, furthering the salability of Alaskan coal). This project studied the relationship between PSD and power plant efficiency, emissions, and mill power consumption for low-rank high-volatile-content Alaskan coal. The emissions studied were CO, CO{sub 2}, NO{sub x}, SO{sub 2}, and Hg (only two tests). The tested PSD range was 42 to 81 percent passing 76 microns. Within the tested range, there was very little correlation between PSD and power plant efficiency, CO, NO{sub x}, and SO{sub 2}. Hg emissions were very low and, therefore, did not allow comparison between grind sizes. Mill power consumption was lower for coarser grinds.« less

Insight into the hydraulics and resilience of Ponderosa pine seedlings using a mechanistic ecohydrologic model

NASA Astrophysics Data System (ADS)

Maneta, M. P.; Simeone, C.; Dobrowski, S.; Holden, Z.; Sapes, G.; Sala, A.; Begueria, S.

2017-12-01

In semiarid regions, drought-induced seedling mortality is considered to be caused by failure in the tree hydraulic column. Understanding the mechanisms that cause hydraulic failure and death in seedlings is important, among other things, to diagnose where some tree species may fail to regenerate, triggering demographic imbalances in the forest that could result in climate-driven shifts of tree species. Ponderosa pine is a common lower tree line species in the western US. Seedlings of ponderosa pine are often subject to low soil water potentials, which require lower water potentials in the xylem and leaves to maintain the negative pressure gradient that drives water upward. The resilience of the hydraulic column to hydraulic tension is species dependent, but from greenhouse experiments, we have identified general tension thresholds beyond which loss of xylem conductivity becomes critical, and mortality in Ponderosa pine seedlings start to occur. We describe this hydraulic behavior of plants using a mechanistic soil-vegetation-atmosphere transfer model. Before we use this models to understand water-stress induced seedling mortality at the landscape scale, we perform a modeling analysis of the dynamics of soil moisture, transpiration, leaf water potential and loss of plant water conductivity using detailed data from our green house experiments. The analysis is done using a spatially distributed model that simulates water fluxes, energy exchanges and water potentials in the soil-vegetation-atmosphere continuum. Plant hydraulic and physiological parameters of this model were calibrated using Monte Carlo methods against information on soil moisture, soil hydraulic potential, transpiration, leaf water potential and percent loss of conductivity in the xylem. This analysis permits us to construct a full portrait of the parameter space for Ponderosa pine seedling and generate posterior predictive distributions of tree response to understand the sensitivity of transpiration

Solid Waste from the Operation and Decommissioning of Power Plants

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

Brown, Marilyn Ann; D'Arcy, Daniel; Lapsa, Melissa Voss

This baseline report examines the solid waste generated by the U.S. electric power industry, including both waste streams resulting from electricity generation and wastes resulting from the decommissioning of power plants. Coal and nuclear plants produce large volumes of waste during electricity generation, and this report describes the policies and procedures for handling these materials. Natural gas and oil-fired power plants face similar waste challenges. Renewables considered in this baseline report include hydropower, wind and solar.

Stomatal responses to changes in vapor pressure deficit reflect tissue-specific differences in hydraulic conductance.

PubMed

Ocheltree, T W; Nippert, J B; Prasad, P V V

2014-01-01

The vapor pressure deficit (D) of the atmosphere can negatively affect plant growth as plants reduce stomatal conductance to water vapor (g(wv)) in response to increasing D, limiting the ability of plants to assimilate carbon. The sensitivity of g(wv) to changes in D varies among species and has been correlated with the hydraulic conductance of leaves (K(leaf) ), but the hydraulic conductance of other tissues has also been implicated in plant responses to changing D. Among the 19 grass species, we found that K(leaf) was correlated with the hydraulic conductance of large longitudinal veins (K(lv), r(2) = 0.81), but was not related to K(root) (r(2) = 0.01). Stomatal sensitivity to D was correlated with K(leaf) relative to total leaf area (r(2) = 0.50), and did not differ between C3 and C4 species. Transpiration (E) increased in response to D, but 8 of the 19 plants showed a decline in E at high D, indicative of an 'apparent feedforward' response. For these individuals, E began to decline at lower values of D in plants with low K(root) (r(2) = 0.72). These results show the significance of both leaf and root hydraulic conductance as drivers of plant responses to evaporative demand. © 2013 John Wiley & Sons Ltd.

4. View of south elevation of power plant, looking north ...

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

4. View of south elevation of power plant, looking north - Naval Air Station Fallon, Power Plant, 800 Complex, off Carson Road near intersection of Pasture & Berney Roads, Fallon, Churchill County, NV

8. View of power plant and radar tower, looking southwest ...

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

8. View of power plant and radar tower, looking southwest - Naval Air Station Fallon, Power Plant, 800 Complex, off Carson Road near intersection of Pasture & Berney Roads, Fallon, Churchill County, NV

2. View of north elevation of power plant, looking south ...

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

2. View of north elevation of power plant, looking south - Naval Air Station Fallon, Power Plant, 800 Complex, off Carson Road near intersection of Pasture & Berney Roads, Fallon, Churchill County, NV

Associations Between Residential Proximity to Power Plants and Adverse Birth Outcomes

PubMed Central

Ha, Sandie; Hu, Hui; Roth, Jeffrey; Kan, Haidong; Xu, Xiaohui

2015-01-01

Few studies have assessed the associations between residential proximity to power plants and adverse birth outcomes including preterm delivery (PTD), very preterm delivery (VPTD), and term low birth weight (LBW). We geocoded 423,719 singleton Florida births born from 2004 to 2005 and all active power plants and determined residential proximity to the nearest power plant for each birth. Prenatal exposure to particulate matter less than 2.5 µm in diameter for women living near different types of power plants was also determined by using National Environmental Public Health Tracking Network data. Logistic regression models were used to test the hypothesized associations. Women who lived closer to coal and solid waste power plants were exposed to higher levels of particulate matter less than 2.5 µm in diameter compared with other types. We observed a 1.8% (95% confidence interval (CI): 1.3, 2.3) increased odds for PTD, 2.2% (95% CI: 1.0, 3.4) for VPTD, and 1.1% (95% CI: 0.2, 2.0) for term LBW for each 5 km closer to any power plant. When stratifying by different fuel type, we found that only solid waste had an association with term LBW, whereas oil, gas, and solid waste all had an association with PTD and VPTD. Results were consistent when exposure was categorized by number of power plants. Our study found evidence of increasing odds of adverse birth outcomes among infants born to pregnant women living closer to power plants. More research is warranted to better understand the causal relationship. PMID:26121989

Efficiency limit factor analysis for the Francis-99 hydraulic turbine

NASA Astrophysics Data System (ADS)

Zeng, Y.; Zhang, L. X.; Guo, J. P.; Guo, Y. K.; Pan, Q. L.; Qian, J.

2017-01-01

The energy loss in hydraulic turbine is the most direct factor that affects the efficiency of the hydraulic turbine. Based on the analysis theory of inner energy loss of hydraulic turbine, combining the measurement data of the Francis-99, this paper calculates characteristic parameters of inner energy loss of the hydraulic turbine, and establishes the calculation model of the hydraulic turbine power. Taken the start-up test conditions given by Francis-99 as case, characteristics of the inner energy of the hydraulic turbine in transient and transformation law are researched. Further, analyzing mechanical friction in hydraulic turbine, we think that main ingredients of mechanical friction loss is the rotation friction loss between rotating runner and water body, and defined as the inner mechanical friction loss. The calculation method of the inner mechanical friction loss is given roughly. Our purpose is that explore and research the method and way increasing transformation efficiency of water flow by means of analysis energy losses in hydraulic turbine.

Solar pond power plant feasibility study for Davis, California

NASA Technical Reports Server (NTRS)

Wu, Y. C.; Singer, M. J.; Marsh, H. E.; Harris, J.; Walton, A. L.

1982-01-01

The feasibility of constructing a solar pond power plant at Davis, California was studied. Site visits, weather data compilation, soil and water analyses, conceptual system design and analyses, a material and equipment market survey, conceptual site layout, and a preliminary cost estimate were studied. It was concluded that a solar pond power plant is technically feasible, but economically unattractive. The relatively small scale of the proposed plant and the high cost of importing salt resulted in a disproportionately high capital investment with respect to the annual energy production capacity of the plant. Cycle optimization and increased plant size would increase the economical attractiveness of the proposed concept.

75 FR 13323 - James A. Fitzpatrick Nuclear Power Plant; Exemption

Federal Register 2010, 2011, 2012, 2013, 2014

2010-03-19

... Power Plant; Exemption 1.0 Background Entergy Nuclear Operations, Inc. (the licensee) is the holder of Facility Operating License No. DPR-59, which authorizes operation of the James A. FitzPatrick Nuclear Power... nuclear power plants that were licensed before January 1, 1979, satisfy the requirements of 10 CFR Part 50...

18. Power plant engine piping floor plan, sheet 71 of ...

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

18. Power plant engine piping floor plan, sheet 71 of 130 - Naval Air Station Fallon, Power Plant, 800 Complex, off Carson Road near intersection of Pasture & Berney Roads, Fallon, Churchill County, NV

15. Power plant elevations and cross sections, sheet 64 of ...

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

15. Power plant elevations and cross sections, sheet 64 of 130 - Naval Air Station Fallon, Power Plant, 800 Complex, off Carson Road near intersection of Pasture & Berney Roads, Fallon, Churchill County, NV

Availability Performance Analysis of Thermal Power Plants

NASA Astrophysics Data System (ADS)

Bhangu, Navneet Singh; Singh, Rupinder; Pahuja, G. L.

2018-03-01

This case study presents the availability evaluation method of thermal power plants for conducting performance analysis in Indian environment. A generic availability model has been proposed for a maintained system (thermal plants) using reliability block diagrams and fault tree analysis. The availability indices have been evaluated under realistic working environment using inclusion exclusion principle. Four year failure database has been used to compute availability for different combinatory of plant capacity, that is, full working state, reduced capacity or failure state. Availability is found to be very less even at full rated capacity (440 MW) which is not acceptable especially in prevailing energy scenario. One of the probable reason for this may be the difference in the age/health of existing thermal power plants which requires special attention of each unit from case to case basis. The maintenance techniques being used are conventional (50 years old) and improper in context of the modern equipment, which further aggravate the problem of low availability. This study highlights procedure for finding critical plants/units/subsystems and helps in deciding preventive maintenance program.

Stem hydraulic capacitance decreases with drought stress: implications for modelling tree hydraulics in the Mediterranean oak Quercus ilex.

PubMed

Salomón, Roberto L; Limousin, Jean-Marc; Ourcival, Jean-Marc; Rodríguez-Calcerrada, Jesús; Steppe, Kathy

2017-08-01

Hydraulic modelling is a primary tool to predict plant performance in future drier scenarios. However, as most tree models are validated under non-stress conditions, they may fail when water becomes limiting. To simulate tree hydraulic functioning under moist and dry conditions, the current version of a water flow and storage mechanistic model was further developed by implementing equations that describe variation in xylem hydraulic resistance (R X ) and stem hydraulic capacitance (C S ) with predawn water potential (Ψ PD ). The model was applied in a Mediterranean forest experiencing intense summer drought, where six Quercus ilex trees were instrumented to monitor stem diameter variations and sap flow, concurrently with measurements of predawn and midday leaf water potential. Best model performance was observed when C S was allowed to decrease with decreasing Ψ PD . Hydraulic capacitance decreased from 62 to 25 kg m -3  MPa -1 across the growing season. In parallel, tree transpiration decreased to a greater extent than the capacitive water release and the contribution of stored water to transpiration increased from 2.0 to 5.1%. Our results demonstrate the importance of stored water and seasonality in C S for tree hydraulic functioning, and they suggest that C S should be considered to predict the drought response of trees with models. © 2017 John Wiley & Sons Ltd.

Drought-induced embolism in stems of sunflower: A comparison of in vivo micro-CT observations and destructive hydraulic measurements.

PubMed

Savi, Tadeja; Miotto, Andrea; Petruzzellis, Francesco; Losso, Adriano; Pacilè, Serena; Tromba, Giuliana; Mayr, Stefan; Nardini, Andrea

2017-11-01

Vulnerability curves (VCs) are a useful tool to investigate the susceptibility of plants to drought-induced hydraulic failure, and several experimental techniques have been used for their measurement. The validity of the bench dehydration method coupled to hydraulic measurements, considered as a 'golden standard', has been recently questioned calling for its validation with non-destructive methods. We compared the VCs of a herbaceous crop plant (Helianthus annuus) obtained during whole-plant dehydration followed by i) hydraulic flow measurements in stem segments (classical destructive method) or by ii) in vivo micro-CT observations of stem xylem conduits in intact plants. The interpolated P 50 values (xylem water potential inducing 50% loss of hydraulic conductance) were -1.74 MPa and -0.87 MPa for the hydraulic and the micro-CT VC, respectively. Interpolated P 20 values were similar, while P 50 and P 80 were significantly different, as evidenced by non-overlapping 95% confidence intervals. Our results did not support the tension-cutting artefact, as no overestimation of vulnerability was observed when comparing the hydraulic VC to that obtained with in vivo imaging. After one scan, 25% of plants showed signs of x-ray induced damage, while three successive scans caused the formation of a circular brownish scar in all tested plants. Our results support the validity of hydraulic measurements of samples excised under tension provided standard sampling and handling protocols are followed, but also show that caution is needed when investigating vital plant processes with x-ray imaging. Copyright © 2017 Elsevier Masson SAS. All rights reserved.

21. Power plant engine fuel oil piping diagrams, sheet 83 ...

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

21. Power plant engine fuel oil piping diagrams, sheet 83 of 130 - Naval Air Station Fallon, Power Plant, 800 Complex, off Carson Road near intersection of Pasture & Berney Roads, Fallon, Churchill County, NV

19. Power plant engine pipinglower level plan, sheet 80 of ...

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

19. Power plant engine piping-lower level plan, sheet 80 of 130 - Naval Air Station Fallon, Power Plant, 800 Complex, off Carson Road near intersection of Pasture & Berney Roads, Fallon, Churchill County, NV

20. Power plant engine piping details and schedules, sheet 82 ...

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

20. Power plant engine piping details and schedules, sheet 82 of 130 - Naval Air Station Fallon, Power Plant, 800 Complex, off Carson Road near intersection of Pasture & Berney Roads, Fallon, Churchill County, NV

16. Power plant roof plan and wall sections, sheet 65 ...

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

16. Power plant roof plan and wall sections, sheet 65 of 130 - Naval Air Station Fallon, Power Plant, 800 Complex, off Carson Road near intersection of Pasture & Berney Roads, Fallon, Churchill County, NV

Hydraulic refinement of an intraarterial microaxial blood pump.

PubMed

Siess, T; Reul, H; Rau, G

1995-05-01

Intravascularly operating microaxial pumps have been introduced clinically proving to be useful tools for cardiac assist. However, a number of complications have been reported in literature associated with the extra-corporeal motor and the flexible drive shaft cable. In this paper, a new pump concept is presented which has been mechanically and hydraulically refined during the developing process. The drive shaft cable has been replaced by a proximally integrated micro electric motor and an extra-corporeal power supply. The conduit between pump and power supply consists of only an electrical power cable within the catheter resulting in a device which is indifferent to kinking and small curvature radii. Anticipated insertion difficulties, as a result of a large outer pump diameter, led to a two-step approach with an initial 6,4mm pump version and a secondary 5,4mm version. Both pumps meet the hydraulic requirement of at least 2.5l/min at a differential pressure of 80-100 mmHg. The hydraulic refinements necessary to achieve the anticipated goal are based on ongoing hydrodynamic studies of the flow inside the pumps. Flow visualization on a 10:1 scale model as well as on 1:1 scale pumps have yielded significant improvements in the overall hydraulic performance of the pumps. One example of this iterative developing process by means of geometrical changes on the basis of flow visualization is illustrated for the 6.4mm pump.