Energy Conversion Alternatives Study (ECAS), Westinghouse phase 1. Volume 8: Open-cycle MHD. [energy conversion efficiency and design analysis of electric power plants employing magnetohydrodynamics

NASA Technical Reports Server (NTRS)

Hoover, D. Q.

1976-01-01

Electric power plant costs and efficiencies are presented for three basic open-cycle MHD systems: (1) direct coal fired system, (2) a system with a separately fired air heater, and (3) a system burning low-Btu gas from an integrated gasifier. Power plant designs were developed corresponding to the basic cases with variation of major parameters for which major system components were sized and costed. Flow diagrams describing each design are presented. A discussion of the limitations of each design is made within the framework of the assumptions made.

The Bern Simple Climate Model (BernSCM) v1.0: an extensible and fully documented open-source re-implementation of the Bern reduced-form model for global carbon cycle-climate simulations

NASA Astrophysics Data System (ADS)

Strassmann, Kuno M.; Joos, Fortunat

2018-05-01

The Bern Simple Climate Model (BernSCM) is a free open-source re-implementation of a reduced-form carbon cycle-climate model which has been used widely in previous scientific work and IPCC assessments. BernSCM represents the carbon cycle and climate system with a small set of equations for the heat and carbon budget, the parametrization of major nonlinearities, and the substitution of complex component systems with impulse response functions (IRFs). The IRF approach allows cost-efficient yet accurate substitution of detailed parent models of climate system components with near-linear behavior. Illustrative simulations of scenarios from previous multimodel studies show that BernSCM is broadly representative of the range of the climate-carbon cycle response simulated by more complex and detailed models. Model code (in Fortran) was written from scratch with transparency and extensibility in mind, and is provided open source. BernSCM makes scientifically sound carbon cycle-climate modeling available for many applications. Supporting up to decadal time steps with high accuracy, it is suitable for studies with high computational load and for coupling with integrated assessment models (IAMs), for example. Further applications include climate risk assessment in a business, public, or educational context and the estimation of CO2 and climate benefits of emission mitigation options.

Apparatus and methods for supplying auxiliary steam in a combined cycle system

DOEpatents

Gorman, William G.; Carberg, William George; Jones, Charles Michael

2002-01-01

To provide auxiliary steam, a low pressure valve is opened in a combined cycle system to divert low pressure steam from the heat recovery steam generator to a header for supplying steam to a second combined cycle's steam turbine seals, sparging devices and cooling steam for the steam turbine if the steam turbine and gas turbine lie on a common shaft with the generator. Cooling steam is supplied the gas turbine in the combined cycle system from the high pressure steam turbine. Spent gas turbine cooling steam may augment the low pressure steam supplied to the header by opening a high pressure valve whereby high and low pressure steam flows are combined. An attemperator is used to reduce the temperature of the combined steam in response to auxiliary steam flows above a predetermined flow and a steam header temperature above a predetermined temperature. The auxiliary steam may be used to start additional combined cycle units or to provide a host unit with steam turbine cooling and sealing steam during full-speed no-load operation after a load rejection.

A Magnetohydrodynamic Modeling of the Interchange Cycle for Oblique Northward Interplanetary Magnetic Field

NASA Astrophysics Data System (ADS)

Watanabe, Masakazu; Fujita, Shigeru; Tanaka, Takashi; Kubota, Yasubumi; Shinagawa, Hiroyuki; Murata, Ken T.

2018-01-01

We perform numerical modeling of the interchange cycle in the magnetosphere-ionosphere convection system for oblique northward interplanetary magnetic field (IMF). The interchange cycle results from the coupling of IMF-to-lobe reconnection and lobe-to-closed reconnection. Using a global magnetohydrodynamic simulation code, for an IMF clock angle of 20° (measured from due north), we successfully reproduced the following features of the interchange cycle. (1) In the ionosphere, for each hemisphere, there appears a reverse cell circulating exclusively in the closed field line region (the reciprocal cell). (2) The topology transition of the magnetic field along a streamline near the equatorial plane precisely represents the magnetic flux reciprocation during the interchange cycle. (3) Field-aligned electric fields on the interplanetary-open separatrix and on the open-closed separatrix are those that are consistent with IMF-to-lobe reconnection and lobe-to-closed reconnection, respectively. These three features prove the existence of the interchange cycle in the simulated magnetosphere-ionosphere system. We conclude that the interchange cycle does exist in the real solar wind-magnetosphere-ionosphere system. In addition, the simulation revealed that the reciprocal cell described above is not a direct projection of the diffusion region as predicted by the "vacuum" model in which diffusion is added a priori to the vacuum magnetic topology. Instead, the reciprocal cell is a consequence of the plasma convection system coupled to the so-called NBZ ("northward Bz") field-aligned current system.

Low Power Switching for Antenna Reconfiguration

NASA Technical Reports Server (NTRS)

Bauhahn, Paul E. (Inventor); Becker, Robert C. (Inventor); Meyers, David W. (Inventor); Muldoon, Kelly P. (Inventor)

2008-01-01

Methods and systems for low power switching are provided. In one embodiment, an optical switching system is provided. The system comprises at least one optically controlled switch adapted to maintain one of an open state and a closed state based on an associated light signal; and at least one light source adapted to output the associated light signal to the at least one switch, wherein the at least one light source cycles the light signal on and off, wherein the at least one light source is cycled on for a sufficient duration of time and with a sufficient periodicity to maintain the optically controlled switch in one of an open state and a closed state.

Efficiency analysis of semi-open sorption heat pump systems

DOE PAGES

Gluesenkamp, Kyle R.; Chugh, Devesh; Abdelaziz, Omar; ...

2016-08-10

Sorption systems traditionally fall into two categories: closed (heat pumps and chillers) and open (dehumidification). Recent work has explored the possibility of semi-open systems, which can perform heat pumping or chilling while utilizing ambient humidity as the working fluid of the cycle, and are still capable of being driven by solar, waste, or combustion heat sources. The efficiencies of closed and open systems are well characterized, and can typically be determined from four temperature s. In this work, the performance potential of semi-open systems is explored by adapting expressions for the efficiency of closed and open systems to the novelmore » semi-open systems. A key new parameter is introduced, which involves five temperatures, since both the ambient dry bulb and ambient dew point are used. Furthermore, this additional temperature is necessary to capture the open absorber performance in terms of both the absorption of humidity and sensible heat transfer with surrounding air.« less

Efficiency analysis of semi-open sorption heat pump systems

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

Gluesenkamp, Kyle R.; Chugh, Devesh; Abdelaziz, Omar

Sorption systems traditionally fall into two categories: closed (heat pumps and chillers) and open (dehumidification). Recent work has explored the possibility of semi-open systems, which can perform heat pumping or chilling while utilizing ambient humidity as the working fluid of the cycle, and are still capable of being driven by solar, waste, or combustion heat sources. The efficiencies of closed and open systems are well characterized, and can typically be determined from four temperature s. In this work, the performance potential of semi-open systems is explored by adapting expressions for the efficiency of closed and open systems to the novelmore » semi-open systems. A key new parameter is introduced, which involves five temperatures, since both the ambient dry bulb and ambient dew point are used. Furthermore, this additional temperature is necessary to capture the open absorber performance in terms of both the absorption of humidity and sensible heat transfer with surrounding air.« less

75 FR 67796 - Self-Regulatory Organizations; The National Securities Clearing Corporation; Notice of Filing and...

Federal Register 2010, 2011, 2012, 2013, 2014

2010-11-03

... specified time frames. \\6\\ CNS is an ongoing accounting system which nets today's settling trades with.... This allocation of securities is accomplished through an evening cycle followed by a day cycle. Positions which remain open after the evening cycle may be changed as a result of trades accepted for...

75 FR 38581 - Self-Regulatory Organizations; the Depository Trust Company; Notice of Filing of Proposed Rule...

Federal Register 2010, 2011, 2012, 2013, 2014

2010-07-02

... customer account transfers within specified time frames. \\5\\ CNS is an ongoing accounting system which nets... by book-entry. This allocation of securities is accomplished through an evening cycle followed by a day cycle. Positions which remain open after the evening cycle may be changed as a result of trades...

Benefits of advanced technology in industrial cogeneration

NASA Technical Reports Server (NTRS)

Barna, G. J.; Burns, R. K.

1979-01-01

This broad study is aimed at identifying the most attractive advanced energy conversion systems for industrial cogeneration for the 1985 to 2000 time period and assessing the advantages of advanced technology systems compared to using today's commercially available technology. Energy conversion systems being studied include those using steam turbines, open cycle gas turbines, combined cycles, diesel engines, Stirling engines, closed cycle gas turbines, phosphoric acid and molten carbonate fuel cells and thermionics. Specific cases using today's commercially available technology are being included to serve as a baseline for assessing the advantages of advanced technology.

Countercurrent flow absorber and desorber

DOEpatents

Wilkinson, William H.

1984-01-01

Countercurrent flow absorber and desorber devices are provided for use in absorption cycle refrigeration systems and thermal boosting systems. The devices have increased residence time and surface area resulting in improved heat and mass transfer characteristics. The apparatuses may be incorporated into open cycle thermal boosting systems in which steam serves both as the refrigerant vapor which is supplied to the absorber section and as the supply of heat to drive the desorber section of the system.

Performance and Weight Estimates for an Advanced Open Rotor Engine

NASA Technical Reports Server (NTRS)

Hendricks, Eric S.; Tong, Michael T.

2012-01-01

NASA s Environmentally Responsible Aviation Project and Subsonic Fixed Wing Project are focused on developing concepts and technologies which may enable dramatic reductions to the environmental impact of future generation subsonic aircraft. The open rotor concept (also historically referred to an unducted fan or advanced turboprop) may allow for the achievement of this objective by reducing engine fuel consumption. To evaluate the potential impact of open rotor engines, cycle modeling and engine weight estimation capabilities have been developed. The initial development of the cycle modeling capabilities in the Numerical Propulsion System Simulation (NPSS) tool was presented in a previous paper. Following that initial development, further advancements have been made to the cycle modeling and weight estimation capabilities for open rotor engines and are presented in this paper. The developed modeling capabilities are used to predict the performance of an advanced open rotor concept using modern counter-rotating propeller designs. Finally, performance and weight estimates for this engine are presented and compared to results from a previous NASA study of advanced geared and direct-drive turbofans.

Phase I, open-cycle absorption solar cooling. Part IV. Executive summary analysis and resolution of critical issues and recommendations for Phase II. Final report

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

Wood, B.D.

The objective of this project is to advance lower cost solar cooling technology with the feasibility analysis, design and evaluation of proof-of-concept open cycle solar cooling concepts. The work is divided into three phases, with planned completion of each phase before proceeding with the following phase: Phase I - performance/economic/environmental related analysis and exploratory studies; Phase II - design and construction of an experimental system, including evaluative testing; Phase III - extended system testing during operation and engineering modifications as required. For Phase I, analysis and resolution of critical issues were completed with the objective of developing design specifications formore » an improved prototype OCA system.« less

Variations in Nutrient Cycling and Meltwater Composition Between Ice-Lidded and Open System Cryoconites

NASA Astrophysics Data System (ADS)

Mass, A.

2016-12-01

Cryoconites are small melt pools on the ablation surface of glaciers created by the accumulation of aeolian sediment with a lower albedo than the surrounding ice. While many cryoconites remain open to the surrounding atmosphere, environmental conditions in the McMurdo Dry Valleys of Antarctica often lead to the formation of dense ice lids due to advection from cold winds. These lidded cryoconites are isolated from atmospheric exchange while maintaining subsurface melt in a solid-state greenhouse. The varying conditions for the formation and freeze-thaw cycle of cryoconites lead to a range of biogeochemical processes occurring within the pools. This study analyzed the biochemistry of both open and lidded cryoconite water from six glaciers in the Dry Valleys throughout the initial pulse melt, equilibrium, and refreezing periods in 2013- 2015. Many of the spatial gradients in carbon cycling, solute concentrations, and pH identified for lidded cryoconites exhibited opposite trends for pools in equilibrium with the atmosphere, while temporal gradients were less diverse for open pools.

Countercurrent flow absorber and desorber

DOEpatents

Wilkinson, W.H.

1984-10-16

Countercurrent flow absorber and desorber devices are provided for use in absorption cycle refrigeration systems and thermal boosting systems. The devices have increased residence time and surface area resulting in improved heat and mass transfer characteristics. The apparatuses may be incorporated into open cycle thermal boosting systems in which steam serves both as the refrigerant vapor which is supplied to the absorber section and as the supply of heat to drive the desorber section of the system. 9 figs.

The Wildland Fire Emissions Information System: Providing information for carbon cycle studies with open source geospatial tools

NASA Astrophysics Data System (ADS)

French, N. H.; Erickson, T.; McKenzie, D.

2008-12-01

A major goal of the North American Carbon Program is to resolve uncertainties in understanding and managing the carbon cycle of North America. As carbon modeling tools become more comprehensive and spatially oriented, accurate datasets to spatially quantify carbon emissions from fire are needed, and these data resources need to be accessible to users for decision-making. Under a new NASA Carbon Cycle Science project, Drs. Nancy French and Tyler Erickson, of the Michigan Technological University, Michigan Tech Research Institute (MTRI), are teaming with specialists with the USDA Forest Service Fire and Environmental Research Applications (FERA) team to provide information for mapping fire-derived carbon emissions to users. The project focus includes development of a web-based system to provide spatially resolved fire emissions estimates for North America in a user-friendly environment. The web-based Decision Support System will be based on a variety of open source technologies. The Fuel Characteristic Classification System (FCCS) raster map of fuels and MODIS-derived burned area vector maps will be processed using the Geographic Data Abstraction Library (GDAL) and OGR Simple Features Library. Tabular and spatial project data will be stored in a PostgreSQL/PostGIS, a spatially enabled relational database server. The browser-based user interface will be created using the Django web page framework to allow user input for the decision support system. The OpenLayers mapping framework will be used to provide users with interactive maps within the browser. In addition, the data products will be made available in standard open data formats such as KML, to allow for easy integration into other spatial models and data systems.

Applying MHD Results to a Scramjet Vehicle

DTIC Science & Technology

2007-02-12

flow, arc formation and extinction, high temperature materials, and non-intrusive gas diagnostics. In this report, results from the DOE Program, and...3) Use of demonstrated non-intrusive diagnostics for plasma and boundary layer measurements, and (4) Testing of high - temperature materials for an MHD...cycle systems with researchers in Eindhoven, The Netherlands, and open-cycle systems with personnel at the High Temperature Institute, Moscow, Russia

Design of land-based, foam OTEC plants for bottoming cycles. [Design of waste-heat power plants based on foam OTEC power cycle

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

Molini, A. E.; Zener, C.; Fort, T. Jr.

1979-01-01

Open cycle OTEC technology suggests new concepts for the embediment of commercially feasible bottoming processes to recover energy from, and simultaneously minimize the environmental impact of, hot industrial effluents. The approach would make pollution abatement more economically attractive, yielding clean, low temperature flue gases while recovering a large portion of their thermal energy as electricity. The technology opens the use of lower quality fuels without fear of air pollution caused by their flue gases. Scrubbing would clean and cool the gases, yielding a hot fluid which after proper treatment would serve as the working fluid for open cycle systems usingmore » ambient air as the heat sink. Preparatory to demonstrating the Foam Energy Recovery Open Cycle System (FEROCS) at a 1 MW - 10 MW scale, a structural design was initiated for a unit 380 ft high visualized as an inverted, vertical, reinforced concrete U tube of 36 ft I.D. and walls 11 in. thick. The structure is feasible based on present construction practices with reinforced concrete in Puerto Rico. It would cost approximately $1.4 MM and consume 3800 yds/sup 3/ of concrete and 860 tons of reinforcing steel. To accelerate the demonstration of FEROCS, it is proposed to utilize artificially created temperature differences that can be readily obtained between industrial thermal effluents, for example flue gases at > 250/sup 0/F from fossil fuel fired steam generating plants, as the heat source and ambient air as the heat sink. Results are presented of a study made conceptualizing the process using different scrubbing-working fluids.« less

Construction Operations Building Information Exchange (COBIE)

DTIC Science & Technology

2007-06-01

10 MIMOSA ...objectives. MIMOSA The goals of the Machinery Information Management Open Systems Alli- ance ( MIMOSA ) organization include the creation of open...information standards for life-cycle asset management [Johnson 2004]. As shown in Table 2-1 [BP 2004], MIMOSA is one of many standards that have been

NASA Open Rotor Noise Research

NASA Technical Reports Server (NTRS)

Envia, Ed

2010-01-01

Owing to their inherent fuel burn efficiency advantage compared with the current generation high bypass ratio turbofan engines, there is resurgent interest in developing open rotor propulsion systems for powering the next generation commercial aircraft. However, to make open rotor systems truly competitive, they must be made to be acoustically acceptable too. To address this challenge, NASA in collaboration with industry is exploring the design space for low-noise open rotor propulsion systems. The focus is on the system level assessment of the open rotors compared with other candidate concepts like the ultra high bypass ratio cycle engines. To that end there is an extensive research effort at NASA focused on component testing and diagnostics of the open rotor acoustic performance as well as assessment and improvement of open rotor noise prediction tools. In this presentation and overview of the current NASA research on open rotor noise will be provided. Two NASA projects, the Environmentally Responsible Aviation Project and the Subsonic Fixed Wing Project, have been funding this research effort.

Health and safety: Preliminary comparative assessment of the Satellite Power System (SPS) and other energy alternatives

NASA Technical Reports Server (NTRS)

Habegger, L. J.; Gasper, J. R.; Brown, C.

1980-01-01

Data readily available from the literature were used to make an initial comparison of the health and safety risks of a fission power system with fuel reprocessing; a combined-cycle coal power system with a low-Btu gasifier and open-cycle gas turbine; a central-station, terrestrial, solar photovoltaic power system; the satellite power system; and a first-generation fusion system. The assessment approach consists of the identification of health and safety issues in each phase of the energy cycle from raw material extraction through electrical generation, waste disposal, and system deactivation; quantitative or qualitative evaluation of impact severity; and the rating of each issue with regard to known or potential impact level and level of uncertainty.

Ocean energy program summary. Volume 2: Research summaries

NASA Astrophysics Data System (ADS)

1990-01-01

The oceans are the world's largest solar energy collector and storage system. Covering 71 percent of the earth's surface, this stored energy is realized as waves, currents, and thermal salinity gradients. The purpose of the Federal Ocean Energy Technology (OET) Program is to develop techniques that harness this ocean energy in a cost effective and environmentally acceptable manner. The OET Program seeks to develop ocean energy technology to a point where the commercial sector can assess whether applications of the technology are viable energy conversion alternatives or supplements to systems. Past studies conducted by the U.S. Department of Energy (DOE) have identified ocean thermal energy conversion (OTEC) as the largest potential contributor to United States energy supplies from the ocean resource. As a result, the OET Program concentrates on research to advance OTEC technology. Current program emphasis has shifted to open-cycle OTEC power system research because the closed-cycle OTEC system is at a more advanced stage of development and has already attracted industrial interest. During FY 1989, the OET Program focused primarily on the technical uncertainties associated with near-shore open-cycle OTEC systems ranging in size from 2 to 15 MW(sub e). Activities were performed under three major program elements: thermodynamic research and analysis, experimental verification and testing, and materials and structures research. These efforts addressed a variety of technical problems whose resolution is crucial to demonstrating the viability of open-cycle OTEC technology. This publications is one of a series of documents on the Renewable Energy programs sponsored by the U.S. Department of Energy. An overview of all the programs is available, entitled Programs in Renewable Energy.

A simple object-oriented and open-source model for scientific and policy analyses of the global climate system – Hector v1.0

DOE PAGES

Hartin, Corinne A.; Patel, Pralit L.; Schwarber, Adria; ...

2015-04-01

Simple climate models play an integral role in the policy and scientific communities. They are used for climate mitigation scenarios within integrated assessment models, complex climate model emulation, and uncertainty analyses. Here we describe Hector v1.0, an open source, object-oriented, simple global climate carbon-cycle model. This model runs essentially instantaneously while still representing the most critical global-scale earth system processes. Hector has a three-part main carbon cycle: a one-pool atmosphere, land, and ocean. The model's terrestrial carbon cycle includes primary production and respiration fluxes, accommodating arbitrary geographic divisions into, e.g., ecological biomes or political units. Hector actively solves the inorganicmore » carbon system in the surface ocean, directly calculating air–sea fluxes of carbon and ocean pH. Hector reproduces the global historical trends of atmospheric [CO 2], radiative forcing, and surface temperatures. The model simulates all four Representative Concentration Pathways (RCPs) with equivalent rates of change of key variables over time compared to current observations, MAGICC (a well-known simple climate model), and models from the 5th Coupled Model Intercomparison Project. Hector's flexibility, open-source nature, and modular design will facilitate a broad range of research in various areas.« less

New control strategies for neuroprosthetic systems.

PubMed

Crago, P E; Lan, N; Veltink, P H; Abbas, J J; Kantor, C

1996-04-01

The availability of techniques to artificially excite paralyzed muscles opens enormous potential for restoring both upper and lower extremity movements with neuroprostheses. Neuroprostheses must stimulate muscle, and control and regulate the artificial movements produced. Control methods to accomplish these tasks include feedforward (open-loop), feedback, and adaptive control. Feedforward control requires a great deal of information about the biomechanical behavior of the limb. For the upper extremity, an artificial motor program was developed to provide such movement program input to a neuroprosthesis. In lower extremity control, one group achieved their best results by attempting to meet naturally perceived gait objectives rather than to follow an exact joint angle trajectory. Adaptive feedforward control, as implemented in the cycle-to-cycle controller, gave good compensation for the gradual decrease in performance observed with open-loop control. A neural network controller was able to control its system to customize stimulation parameters in order to generate a desired output trajectory in a given individual and to maintain tracking performance in the presence of muscle fatigue. The authors believe that practical FNS control systems must exhibit many of these features of neurophysiological systems.

Magnetohydrodynamics (MHD) Engineering Test Facility (ETF) 200 MWe power plant Conceptual Design Engineering Report (CDER)

NASA Technical Reports Server (NTRS)

1981-01-01

The reference conceptual design of the magnetohydrodynamic (MHD) Engineering Test Facility (ETF), a prototype 200 MWe coal-fired electric generating plant designed to demonstrate the commercial feasibility of open cycle MHD, is summarized. Main elements of the design, systems, and plant facilities are illustrated. System design descriptions are included for closed cycle cooling water, industrial gas systems, fuel oil, boiler flue gas, coal management, seed management, slag management, plant industrial waste, fire service water, oxidant supply, MHD power ventilating

Magnetohydrodynamics (MHD) Engineering Test Facility (ETF) 200 MWe power plant Conceptual Design Engineering Report (CDER)

NASA Astrophysics Data System (ADS)

1981-09-01

The reference conceptual design of the magnetohydrodynamic (MHD) Engineering Test Facility (ETF), a prototype 200 MWe coal-fired electric generating plant designed to demonstrate the commercial feasibility of open cycle MHD, is summarized. Main elements of the design, systems, and plant facilities are illustrated. System design descriptions are included for closed cycle cooling water, industrial gas systems, fuel oil, boiler flue gas, coal management, seed management, slag management, plant industrial waste, fire service water, oxidant supply, MHD power ventilating

Approaches to Legacy System Evolution.

DTIC Science & Technology

1997-12-01

such as migrating legacy systems, to more distributed open environments. This framework draws out the important global issues early in the planning...ongoing system evolution initiatives, for drawing out important global issues early in the planning cycle using the checklists as a guide, and for

A Review of RedOx Cycling of Solid Oxide Fuel Cells Anode

PubMed Central

Faes, Antonin; Hessler-Wyser, Aïcha; Zryd, Amédée; Van Herle, Jan

2012-01-01

Solid oxide fuel cells are able to convert fuels, including hydrocarbons, to electricity with an unbeatable efficiency even for small systems. One of the main limitations for long-term utilization is the reduction-oxidation cycling (RedOx cycles) of the nickel-based anodes. This paper will review the effects and parameters influencing RedOx cycles of the Ni-ceramic anode. Second, solutions for RedOx instability are reviewed in the patent and open scientific literature. The solutions are described from the point of view of the system, stack design, cell design, new materials and microstructure optimization. Finally, a brief synthesis on RedOx cycling of Ni-based anode supports for standard and optimized microstructures is depicted. PMID:24958298

Development of an Open Rotor Cycle Model in NPSS Using a Multi-Design Point Approach

NASA Technical Reports Server (NTRS)

Hendricks, Eric S.

2011-01-01

NASA's Environmentally Responsible Aviation Project and Subsonic Fixed Wing Project are focused on developing concepts and technologies which may enable dramatic reductions to the environmental impact of future generation subsonic aircraft (Refs. 1 and 2). The open rotor concept (also referred to as the Unducted Fan or advanced turboprop) may allow the achievement of this objective by reducing engine emissions and fuel consumption. To evaluate its potential impact, an open rotor cycle modeling capability is needed. This paper presents the initial development of an open rotor cycle model in the Numerical Propulsion System Simulation (NPSS) computer program which can then be used to evaluate the potential benefit of this engine. The development of this open rotor model necessitated addressing two modeling needs within NPSS. First, a method for evaluating the performance of counter-rotating propellers was needed. Therefore, a new counter-rotating propeller NPSS component was created. This component uses propeller performance maps developed from historic counter-rotating propeller experiments to determine the thrust delivered and power required. Second, several methods for modeling a counter-rotating power turbine within NPSS were explored. These techniques used several combinations of turbine components within NPSS to provide the necessary power to the propellers. Ultimately, a single turbine component with a conventional turbine map was selected. Using these modeling enhancements, an open rotor cycle model was developed in NPSS using a multi-design point approach. The multi-design point (MDP) approach improves the engine cycle analysis process by making it easier to properly size the engine to meet a variety of thrust targets throughout the flight envelope. A number of design points are considered including an aerodynamic design point, sea-level static, takeoff and top of climb. The development of this MDP model was also enabled by the selection of a simple power management scheme which schedules propeller blade angles with the freestream Mach number. Finally, sample open rotor performance results and areas for further model improvements are presented.

Construction Operations Building Information Exchange (COBIE): Requirements Definition and Pilot Implementation Standard

DTIC Science & Technology

2007-06-01

10 MIMOSA ...objectives. MIMOSA The goals of the Machinery Information Management Open Systems Alli- ance ( MIMOSA ) organization include the creation of open...information standards for life-cycle asset management [Johnson 2004]. As shown in Table 2-1 [BP 2004], MIMOSA is one of many standards that have been

The Life Cycle Evaluation Model of External Diseconomy of Open-loop Supply Chain

NASA Astrophysics Data System (ADS)

Liu, Qian; Hu, Tianjun

2017-08-01

In recent years, with the continuous deterioration of pollution, resource space is gradually narrowed, the number of waste items increased, people began to use the method of recycling on waste products to ease the pressure on the environment. This paper adopted the external diseconomy of open-loop supply chain as the research object and constructed the model by the life cycle evaluation method, comparative analysis through the case. This paper also concludes that the key to solving the problem is to realize the closed-loop supply chain and building reverse logistics system is of great significance.

Cadmium cycling in the water column of the Kuroshio-Oyashio Extension region: Insights from dissolved and particulate isotopic composition

NASA Astrophysics Data System (ADS)

Yang, Shun-Chung; Zhang, Jing; Sohrin, Yoshiki; Ho, Tung-Yuan

2018-07-01

We measured dissolved and particulate Cd isotopic composition in the water column of a meridional transect across the Kuroshio-Oyashio Extension region in a Japanese GEOTRACES cruise to investigate the relative influence of physical and biogeochemical processes on Cd cycling in the Northwestern Pacific Ocean. Located at 30-50°N along 165°E, the transect across the extension region possesses dramatic hydrographic contrast. Cold surface water and a relatively narrow and shallow thermocline characterizes the Oyashio Extension region in contrast to a relatively warm and highly stratified surface water and thermocline in the Kuroshio Extension region. The contrasting hydrographic distinction at the study site provides us with an ideal platform to investigate the spatial variations of Cd isotope fractionation systems in the ocean. Particulate samples demonstrated biologically preferential uptake of light Cd isotopes, and the fractionation effect varied dramatically in the surface water of the two regions, with relatively large fractionation factors in the Oyashio region. Based on the relationship of dissolved Cd concentrations and isotopic composition, we found that a closed system fractionation model can reasonably explain the relationship in the Kuroshio region. However, using dissolved Cd isotopic data, either a closed system or steady-state open system fractionation model may explain the relationship in the surface water of the Oyashio region. Particulate δ114/110Cd data further supports that the surface water of the Oyashio region matches a steady-state open system model more closely. Contrary to the surface water, the distribution of potential density exhibits comparable patterns with Cd elemental and isotopic composition in the thermocline and deep water in the two extension regions, showing that physical processes are the dominant forcing controlling Cd cycling in the deep waters. The results demonstrate that Cd isotope fractionation can match either a closed or open system Rayleigh fractionation model, depending on the relative contribution of physical and biogeochemical processes on its cycling.

Effect of Knowledge Integration Activities on Students' Perception of the Earth's Crust as a Cyclic System.

ERIC Educational Resources Information Center

Kali, Yael; Orion, Nir; Eylon, Bat-Sheva

2003-01-01

Characterizes students' understanding of the rock cycle system. Examines effects of a knowledge integration activity on their system thinking. Interprets answers to an open-ended test using a systems thinking continuum ranging from a completely static view of the system to an understanding of the system's cyclic nature. Reports meaningful…

An Assessment of Students' Understanding of Ecosystem Concepts: Conflating Ecological Systems and Cycles

ERIC Educational Resources Information Center

Jordan, Rebecca; Gray, Steven; Demeter, Marylee; Lui, Lei; Hmelo-Silver, Cindy E.

2009-01-01

Teaching ecological concepts in schools is important in promoting natural science and environmental education for young learners. Developing educational programs is difficult, however, because of complicated ecological processes operating on multiple levels, the unlimited nature of potential system interactions (given the openness of systems), and…

Oscillations in rational economies.

PubMed

Mishchenko, Yuriy

2014-01-01

Economic (business) cycles are some of the most noted features of market economies, also ranked among the most serious of economic problems. Despite long historical persistence, the nature and the origin of business cycles remain controversial. In this paper we investigate the problem of the nature of business cycles from the positions of the market systems viewed as complex systems of many interacting market agents. We show that the development of cyclic instabilities in these settings can be traced down to just two fundamental factors - the competition of market agents for market shares in the settings of an open market, and the depression of market caused by accumulation of durable overproduced commodities on the market. These findings present the problem of business cycles in a new light as a systemic property of efficient market systems emerging directly from the free market competition itself, and existing in market economies at a very fundamental level.

Oscillations in Rational Economies

PubMed Central

Mishchenko, Yuriy

2014-01-01

Economic (business) cycles are some of the most noted features of market economies, also ranked among the most serious of economic problems. Despite long historical persistence, the nature and the origin of business cycles remain controversial. In this paper we investigate the problem of the nature of business cycles from the positions of the market systems viewed as complex systems of many interacting market agents. We show that the development of cyclic instabilities in these settings can be traced down to just two fundamental factors – the competition of market agents for market shares in the settings of an open market, and the depression of market caused by accumulation of durable overproduced commodities on the market. These findings present the problem of business cycles in a new light as a systemic property of efficient market systems emerging directly from the free market competition itself, and existing in market economies at a very fundamental level. PMID:24505319

A tide prediction and tide height control system for laboratory mesocosms

PubMed Central

Long, Jeremy D.

2015-01-01

Experimental mesocosm studies of rocky shore and estuarine intertidal systems may benefit from the application of natural tide cycles to better replicate variation in immersion time, water depth, and attendant fluctuations in abiotic and edaphic conditions. Here we describe a stand-alone microcontroller tide prediction open-source software program, coupled with a mechanical tidal elevation control system, which allows continuous adjustment of aquarium water depths in synchrony with local tide cycles. We used this system to monitor the growth of Spartina foliosa marsh cordgrass and scale insect herbivores at three simulated shore elevations in laboratory mesocosms. Plant growth decreased with increasing shore elevation, while scale insect population growth on the plants was not strongly affected by immersion time. This system shows promise for a range of laboratory mesocosm studies where natural tide cycling could impact organism performance or behavior, while the tide prediction system could additionally be utilized in field experiments where treatments need to be applied at certain stages of the tide cycle. PMID:26623195

An Open IMS-Based User Modelling Approach for Developing Adaptive Learning Management Systems

ERIC Educational Resources Information Center

Boticario, Jesus G.; Santos, Olga C.

2007-01-01

Adaptive LMS have not yet reached the eLearning marketplace due to methodological, technological and management open issues. At aDeNu group, we have been working on two key challenges for the last five years in related research projects. Firstly, develop the general framework and a running architecture to support the adaptive life cycle (i.e.,…

Scaling of chew cycle duration in primates.

PubMed

Ross, Callum F; Reed, David A; Washington, Rhyan L; Eckhardt, Alison; Anapol, Fred; Shahnoor, Nazima

2009-01-01

The biomechanical determinants of the scaling of chew cycle duration are important components of models of primate feeding systems at all levels, from the neuromechanical to the ecological. Chew cycle durations were estimated in 35 species of primates and analyzed in conjunction with data on morphological variables of the feeding system estimating moment of inertia of the mandible and force production capacity of the chewing muscles. Data on scaling of primate chew cycle duration were compared with the predictions of simple pendulum and forced mass-spring system models of the feeding system. The gravity-driven pendulum model best predicts the observed cycle duration scaling but is rejected as biomechanically unrealistic. The forced mass-spring model predicts larger increases in chew cycle duration with size than observed, but provides reasonable predictions of cycle duration scaling. We hypothesize that intrinsic properties of the muscles predict spring-like behavior of the jaw elevator muscles during opening and fast close phases of the jaw cycle and that modulation of stiffness by the central nervous system leads to spring-like properties during the slow close/power stroke phase. Strepsirrhines show no predictable relationship between chew cycle duration and jaw length. Anthropoids have longer chew cycle durations than nonprimate mammals with similar mandible lengths, possibly due to their enlarged symphyses, which increase the moment of inertia of the mandible. Deviations from general scaling trends suggest that both scaling of the jaw muscles and the inertial properties of the mandible are important in determining the scaling of chew cycle duration in primates.

Evaluation of coated columbium alloy heat shields for space shuttle thermal protection system application. Volume 2, phase 2: Subsize heat shield and small size TPS evaluation

NASA Technical Reports Server (NTRS)

Black, W. E.

1973-01-01

Initially a trade study was conducted of seven heat shield configurations. These were evaluated for structural reliability, fabricability, weight, inspectability, and refurbishability. Two concepts, a tee-stiffened and an open corrugation, were selected as offering the most potential for system success. Fourteen subsize heat shields of a full scale section were fabricated from C-129Y and Cb-752 and silicide coated with R-512E. These subsize panels were subjected to a simulated flight profile representing temperature, local surface pressures, and applied pressure differential loads. All corrugated panels of both alloys sustained 100 cycles without structural or coating failure. All Cb-752/R-512E panels performed well with one panel being successfully repaired after 66 cycles and completing 100 cycles. As a result of this evaluating the Cb-752/R-512E system was selected for hardware application during the subsequent phases. In addition, the tee-stiffened configuration was selected for further development and application in Phase III. This selection was based on an overall assessment of relative weight, cost, and structural performance of the tee-stiffened and open corrugation TPS.

Design of catalytic monoliths for closed-cycle carbon dioxide lasers

NASA Technical Reports Server (NTRS)

Herz, R. K.; Guinn, K.; Goldblum, S.; Noskowski, E.

1989-01-01

Pulsed carbon dioxide (CO2) lasers have many applications in aeronautics, space research, weather monitoring and other areas. Full exploitation of the potential of these lasers in hampered by the dissociation of CO2 that occurs during laser operation. The development of closed-cycle CO2 lasers requires active CO-O2 recombination (CO oxidation) catalyst and design methods for implementation of catalysts in CO2 laser systems. A monolith catalyst section model and associated design computer program, LASCAT, are presented to assist in the design of a monolith catalyst section of a closed cycle CO2 laser system. Using LASCAT,the designer is able to specify a number of system parameters and determine the monolith section performance. Trade-offs between the catalyst activity, catalyst dimensions, monolith dimensions, pressure drop, O2 conversion, and other variables can be explored and adjusted to meet system design specifications. An introduction describes a typical closed-cycle CO2 system, and indicates some advantages of a closed cycle laser system over an open cycle system and some advantages of monolith support over other types of supports. The development and use of a monolith catalyst model is presented. The results of a design study and a discussion of general design rules are given.

Performance Comparison of High-Speed Dual-Pneumatic Vitrectomy Cutters during Simulated Vitrectomy with Balanced Salt Solution.

PubMed

Abulon, Dina Joy K; Buboltz, David C

2015-02-01

To measure flow rate of balanced salt solution and IOP during simulated vitrectomy using two sets of high-speed dual-pneumatic probes. A closed-model eye system measured IOP and flow rate of a balanced salt solution through infusion cannula. The Constellation Vision System was tested with two sets of high-speed dual-pneumatic probes (UltraVit 23-gauge and enhanced 25+-gauge 5000-cpm probes; UltraVit 23-gauge and enhanced 25+-gauge 7500-cpm probes; n = 6 each) under different vacuum levels and cut rates in three duty cycle modes. In both probe sets, flow rates were dependent on cut rate with the biased open and biased closed duty cycles. Flow rates were highest with the biased open duty cycle, lower with the 50/50 duty cycle, and lowest with the biased closed duty cycle. IOP, as expected, was inversely associated with flow rate using both probe sets. The 7500-cpm probes offer greater control and customization compared with 5000-cpm probes under certain experimental conditions. At maximum cut rates, performance of 7500-cpm probes was similar to that of 5000-cpm probes, suggesting that 7500-cpm probes may be used without sacrifice of flow rate and IOP stability. Customization of vitrectomy parameters allows greater surgeon control during vitrectomy and may expand the usefulness of vitrectomy probes.

High-Efficiency Low-Cost Solar Receiver for Use Ina a Supercritical CO 2 Recompression Cycle

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

Sullivan, Shaun D.; Kesseli, James; Nash, James

This project has performed solar receiver designs for two supercritical carbon dioxide (sCO 2) power cycles. The first half of the program focused on a nominally 2 MWe power cycle, with a receiver designed for test at the Sandia Solar Thermal Test Facility. This led to an economical cavity-type receiver. The second half of the program focused on a 10 MWe power cycle, incorporating a surround open receiver. Rigorous component life and performance testing was performed in support of both receiver designs. The receiver performance objectives are set to conform to the US DOE goals of 6¢/kWh by 2020 .more » Key findings for both cavity-type and direct open receiver are highlighted below: A tube-based absorber design is impractical at specified temperatures, pressures and heat fluxes for the application; a plate-fin architecture however has been shown to meet performance and life targets; the $148/kW th cost of the design is significantly less than the SunShot cost target with a margin of 30%; the proposed receiver design is scalable, and may be applied to both modular cavity-type installations as well as large utility-scale open receiver installations; the design may be integrated with thermal storage systems, allowing for continuous high-efficiency electrical production during off-sun hours; costs associated with a direct sCO 2 receiver for a sCO 2 Brayton power cycle are comparable to those of a typical molten salt receiver; lifetimes in excess of the 90,000 hour goal are achievable with an optimal cell geometry; the thermal performance of the Brayton receiver is significantly higher than the industry standard, and enables at least a 30% efficiency improvement over the performance of the baseline steam-Rankine boiler/cycle system; brayton’s patent-pending quartz tube window provides a greater than five-percent efficiency benefit to the receiver by reducing both convection and radiation losses.« less

Closed-Loop Control of Vortex Formation in Separated Flows

NASA Technical Reports Server (NTRS)

Colonius, Tim; Joe, Won Tae; MacMynowski, Doug; Rowley, Clancy; Taira, Sam; Ahuja, Sunil

2010-01-01

In order to phase lock the flow at the desired shedding cycle, particularly at Phi,best, We designed a feedback compensator. (Even though the open-loop forcing at Wf below Wn can lead to phase-locked limit cycles with a high average lift,) This feedback controller resulted in the phase-locked limit cycles that the open-loop control could not achieve for alpha=30 and 40 Particularly for alpha=40, the feedback was able to stabilize the limit cycle that was not stable with any of the open-loop periodic forcing. This results in stable phase-locked limit cycles for a larger range of forcing frequencies than the open-loop control. Also, it was shown that the feedback achieved the high-lift unsteady flow states that open-loop control could not sustain even after the states have been achieved for a long period of time.

Mechanical, Thermal, and Electrical Energy Storage in a Single Working Body: Electrification and Thermal Effects upon Pressure-Induced Water Intrusion-Extrusion in Nanoporous Solids.

PubMed

Grosu, Yaroslav; Mierzwa, Michał; Eroshenko, Valentine A; Pawlus, Sebastian; Chorażewski, Mirosław; Nedelec, Jean-Marie; Grolier, Jean-Pierre E

2017-03-01

This paper presents the first experimental evidence of pronounced electrification effects upon reversible cycle of forced water intrusion-extrusion in nanoporous hydrophobic materials. Recorded generation of electricity combined with high-pressure calorimetric measurements improves the energy balance of {nanoporous solid + nonwetting liquid} systems by compensating mechanical and thermal energy hysteresis in the cycle. Revealed phenomena provide a novel way of "mechanical to electrical" and/or "thermal to electrical" energy transformation with unprecedented efficiency and additionally open a perspective to increase the efficiency of numerous energy applications based on such systems taking advantage of electricity generation during operational cycle.

Advanced deep sea diving equipment

NASA Technical Reports Server (NTRS)

Danesi, W. A.

1972-01-01

Design requirements are generated for a deep sea heavy duty diving system to equip salvage divers with equipment and tools that permit work of the same quality and in times approaching that done on the surface. The system consists of a helmet, a recirculator for removing carbon dioxide, and the diver's dress. The diver controls the inlet flow by the recirculatory control valve and is able to change closed cycle operation to open cycle if malfunction occurs. Proper function of the scrubber in the recirculator minimizes temperature and humidity effects as it filters the returning air.

Implementation and performance evaluation open-source controller for precision control of gripper

NASA Astrophysics Data System (ADS)

Lee, Seung-Yong; Ham, Un-Hyeong; Park, Young-Woo; Jung, Hak-Sang; Jung, Il-Kyun; Lim, Sun

2017-12-01

This paper proposes integrating gripper embedded operating system, which consist of external interface structure for sophisticated gripper control. This system has multiple functions that control the gripping module and measure the pose of the gripper body with respect to contact environment. A controller based on open source only for the gripper is developed and an external communication interface between robot controller and gripper controller is designed. An experimental environment for the fixed-cycle test consists of integrating magic gripper software system and hardware on commercial business. As a result, a deviation is measured approximately 2% and the system were verified for gripper control.

Analysis of temporal variation in human masticatory cycles during gum chewing.

PubMed

Crane, Elizabeth A; Rothman, Edward D; Childers, David; Gerstner, Geoffrey E

2013-10-01

The study investigated modulation of fast and slow opening (FO, SO) and closing (FC, SC) chewing cycle phases using gum-chewing sequences in humans. Twenty-two healthy adult subjects participated by chewing gum for at least 20s on the right side and at least 20s on the left side while jaw movements were tracked with a 3D motion analysis system. Jaw movement data were digitized, and chewing cycle phases were identified and analysed for all chewing cycles in a complete sequence. All four chewing cycle phase durations were more variant than total cycle durations, a result found in other non-human primates. Significant negative correlations existed between the opening phases, SO and FO, and between the closing phases, SC and FC; however, there was less consistency in terms of which phases were negatively correlated both between subjects, and between chewing sides within subjects, compared with results reported in other species. The coordination of intra-cycle phases appears to be flexible and to follow complex rules during gum-chewing in humans. Alternatively, the observed intra-cycle phase relationships could simply reflect: (1) variation in jaw kinematics due to variation in how gum was handled by the tongue on a chew-by-chew basis in our experimental design or (2) by variation due to data sampling noise and/or how phases were defined and identified. Copyright © 2013 Elsevier Ltd. All rights reserved.

Open-type miniature heat pipes

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

Vasiliev, L.L.

1994-01-01

The hypothesis that systems of thermoregulation, similar to open-type micro heat pipes, exist in nature (soils, living organisms, plants) and in a number of technological processes (drying, thermodynamic cycles on solid adsorbents) is considered. The hydrodynamics and heat transfer in such thermoregulation systems differ from the hydrodynamics and heat transfer in classical heat pipes, since their geometrical dimensions are extremely small (dozens of microns), adhesion forces are powerful, the effect of the field of capillary and gravitational forces is significant, and strong interaction between counter-current flows of vapor and liquid takes place.

Driving and latching of the Starlab pointing mirror doors

NASA Technical Reports Server (NTRS)

Beaven, Herbert R., Jr.; Avina, Raymond R.

1990-01-01

The Starlab Experiment, a major SDIO technology initiative, is an attached payload which will be delivered into Earth orbit aboard NASA's Space Shuttle in 1991. Starlab will generate and aim an 80 cm diameter laser beam into space through a large opening in the structure which houses the pointing mirror. Two doors, each somewhat larger than a desktop, cover the opening when the laser optics system is nonoperational. Latch Mechanism Assemblies hold the doors shut during liftoff and ascent and, again, during Orbiter reentry. Each door is powered by a Door Drive System during the many open/close cycles between various experiments. The design, testing, and resultant failure modes of these mechanisms are examined.

The safest parameters for FUS-induced blood-brain barrier opening without effects on the opening volume

NASA Astrophysics Data System (ADS)

Tung, Yao-Sheng; Olumolade, Yemi; Wang, Shutao; Wu, Shih-Ying; Konofagou, Elisa E.

2012-11-01

Acoustic cavitation has been identified as the main physical mechanism for the focused ultrasound (FUS) induced blood-brain barrier (BBB) opening. In this paper, the mechanism of stable cavitation (SC) and inertial cavitation (IC) responsible for BBB opening was investigated. Thirty-three (n=33) mice were intravenously injected with bubbles of 4-5 μm in diameter. The right hippocampus was then sonicated using focused 1.5-MHz ultrasound and three different studies were carried out. First, pulse lengths (PLs) of 0.1, 0.5, 2, and 5 ms at 0.18- MPa peak rarefactional pressure with 5-Hz pulse repetition frequency (PRF) and 5-minute duration were used to identify the threshold of PL using SC. Second, the effects of the duty cycle and exposure time were investigated. Third, the BBB opening size was compared between the SC and the IC. In the case of IC-induced BBB opening, a burst sequence (3-cycles PL; 5-Hz burst repetition frequency (BRF); 30 s duration) at 0.45 MPa was applied. Passive cavitation detection was performed with each sonication to detect whether a broadband response was obtained, i.e., if IC occurred, during BBB opening. The properties of BBB opening were measured through MRI. The threshold of PL for BBB opening was identified between 0.1 and 0.5 ms using SC, but the BBB can be opened in few cycles using IC. The BBB opening volume and normalized intensity increased with the PL, but reached saturation when the PL was above 2 ms. Once the PL threshold was reached, the same exposure time induced a similar BBB opening volume, but longer sonication duration induced higher MR intensity. The duty cycle was found not to play an important role on the BBB opening. Comparable BBB opening volume (20-25 mm3) could be reached between long PL (7500 cycles, i.e., 5 ms) at 0.18 MPa and 3 cycles at 0.45 MPa. 3-kDa fluorescently tagged dextran may be able to diffuse to the parenchyma after IC-induced BBB opening at 0.45 MPa but not after SC-induced BBB opening at 0.18 MPa.

Comparative health and safety assessment of the SPS and alternative electrical generation systems

NASA Astrophysics Data System (ADS)

Habegger, L. J.; Gasper, J. R.; Brown, C. D.

1980-07-01

A comparative analysis of health and safety risks is presented for the Satellite Power System and five alternative baseload electrical generation systems: a low-Btu coal gasification system with an open-cycle gas turbine combined with a steam topping cycle; a light water fission reactor system without fuel reprocessing; a liquid metal fast breeder fission reactor system; a central station terrestrial photovoltaic system; and a first generation fusion system with magnetic confinement. For comparison, risk from a decentralized roof-top photovoltaic system with battery storage is also evaluated. Quantified estimates of public and occupational risks within ranges of uncertainty were developed for each phase of the energy system. The potential significance of related major health and safety issues that remain unquantitied are also discussed.

Comparative health and safety assessment of the SPS and alternative electrical generation systems

NASA Technical Reports Server (NTRS)

Habegger, L. J.; Gasper, J. R.; Brown, C. D.

1980-01-01

A comparative analysis of health and safety risks is presented for the Satellite Power System and five alternative baseload electrical generation systems: a low-Btu coal gasification system with an open-cycle gas turbine combined with a steam topping cycle; a light water fission reactor system without fuel reprocessing; a liquid metal fast breeder fission reactor system; a central station terrestrial photovoltaic system; and a first generation fusion system with magnetic confinement. For comparison, risk from a decentralized roof-top photovoltaic system with battery storage is also evaluated. Quantified estimates of public and occupational risks within ranges of uncertainty were developed for each phase of the energy system. The potential significance of related major health and safety issues that remain unquantitied are also discussed.

A comparison between molten carbonate fuel cells based hybrid systems using air and supercritical carbon dioxide Brayton cycles with state of the art technology

NASA Astrophysics Data System (ADS)

Sánchez, D.; Muñoz de Escalona, J. M.; Chacartegui, R.; Muñoz, A.; Sánchez, T.

A proposal for high efficiency hybrid systems based on molten carbonate fuel cells is presented in this paper. This proposal is based on adopting a closed cycle bottoming gas turbine using supercritical carbon dioxide as working fluid as opposed to open cycle hot air turbines typically used in this type of power generators. First, both bottoming cycles are compared for the same operating conditions, showing that their performances do not differ as much as initially expected, even if the initial objective of reducing compression work is accomplished satisfactorily. In view of these results, a profound review of research and industrial literature is carried out in order to determine realistic specifications for the principal components of the bottoming systems. From this analysis, it is concluded that an appropriate set of specifications must be developed for each bottoming cycle as the performances of compressor, turbine and recuperator differ significantly from one working fluid to another. Thus, when the operating conditions are updated, the performances of the resulting systems show a remarkable advantage of carbon dioxide based systems over conventional air units. Actually, the proposed hybrid system shows its capability to achieve 60% net efficiency, what represents a 10% increase with respect to the reference system.

Open loop, auto reversing liquid nitrogen circulation thermal system for thermo vacuum chamber

NASA Astrophysics Data System (ADS)

Naidu, M. C. A.; Nolakha, Dinesh; Saharkar, B. S.; Kavani, K. M.; Patel, D. R.

2012-11-01

In a thermo vacuum chamber, attaining and controlling low and high temperatures (-100 Deg. C to +120 Deg. C) is a very important task. This paper describes the development of "Open loop, auto reversing liquid nitrogen based thermal system". System specifications, features, open loop auto reversing system, liquid nitrogen flow paths etc. are discussed in this paper. This thermal system consists of solenoid operated cryogenic valves, double embossed thermal plate (shroud), heating elements, temperature sensors and PLC. Bulky items like blowers, heating chambers, liquid nitrogen injection chambers, huge pipe lines and valves were not used. This entire thermal system is very simple to operate and PLC based, fully auto system with auto tuned to given set temperatures. This system requires a very nominal amount of liquid nitrogen (approx. 80 liters / hour) while conducting thermo vacuum tests. This system was integrated to 1.2m dia thermo vacuum chamber, as a part of its augmentation, to conduct extreme temperature cycling tests on passive antenna reflectors of satellites.

Temporo-mandibular joint kinetics and chewing cycles in children. A 3-year follow-up.

PubMed

Bodin, C; Lodetti, G; Marinone, M G

2002-01-01

To report the temporo-mandibular joint (TMJ) kinetics and masticatory function in healthy children. Temporo-mandibular joint palpation and electrognathographic registrations of chewing cycles were repeated for 3 years in order to evaluate changes. Healthy children without systemic pathologies, decayed cavities and previous dental treatment. Electrognathographic (EGN) registration of masticatory cycles and TMJ palpation were carried out on 52 patients (mean age: 5 years 8 months, range: 5 years 1 month, 6 years 8 months), by two university researchers, once a year for 3 consecutive years. TMJ palpation, differentiated TMJ synchronism (simultaneous bilateral opening movement) and TMJ asynchronism (not simultaneous bilateral opening movement), TMJ subluxation and click were observed. Electrognathographic registrations differentiated normal and abnormal jaw chewing cycles, and narrow and large cycles. Temporo-mandibular joint asynchronism was evident in 34 of 52 patients in the primary dentition, in 42 of 52 patients after the eruption of the first permanent molar, and in 31 of 52 patients after the eruption of the permanent incisors. TMJ subluxation increased during the full period of observation. Three temporomandibular clicks appeared after the eruption of the permanent incisors. Altered mastication was not always associated with TMJ disorders. In children, normal chewing cycles can coexist with occlusal discrepancies, cranio-facial growth and TMJ alterations.

Open-cycle OTEC system performance analysis. [Claude cycle

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

Lewandowski, A.A.; Olson, D.A.; Johnson, D.H.

1980-10-01

An algorithm developed to calculate the performance of Claude-Cycle ocean thermal energy conversion (OTEC) systems is described. The algorithm treats each component of the system separately and then interfaces them to form a complete system, allowing a component to be changed without changing the rest of the algorithm. Two components that are subject to change are the evaporator and condenser. For this study we developed mathematical models of a channel-flow evaporator and both a horizontal jet and spray director contact condenser. The algorithm was then programmed to run on SERI's CDC 7600 computer and used to calculate the effect onmore » performance of deaerating the warm and cold water streams before entering the evaporator and condenser, respectively. This study indicates that there is no advantage to removing air from these streams compared with removing the air from the condenser.« less

Emissions performance of abatement technologies over the proposed EEC extra-urban driving cycle

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

VanBeckhoven, L.C.; Rijkeboer, R.C.

1989-01-01

The definition of what is likely to be the new EEC extra-urban cycle has made it possible to determine the emission characteristics of cars fitted with different emissions control equipment. Central to the evaluation program were three versions of experimental lean and dilute burn engines compared with engine modifications and open and closed loop three-way catalyst systems. This paper describes the evaluation program and evaluates its results.

Research and Technology Activities Supporting Closed-Brayton-Cycle Power Conversion System Development

NASA Technical Reports Server (NTRS)

Barrett, Michael J.

2004-01-01

The elements of Brayton technology development emphasize power conversion system risk mitigation. Risk mitigation is achieved by demonstrating system integration feasibility, subsystem/component life capability (particularly in the context of material creep) and overall spacecraft mass reduction. Closed-Brayton-cycle (CBC) power conversion technology is viewed as relatively mature. At the 2-kWe power level, a CBC conversion system Technology Readiness Level (TRL) of six (6) was achieved during the Solar Dynamic Ground Test Demonstration (SD-GTD) in 1998. A TRL 5 was demonstrated for 10 kWe-class CBC components during the development of the Brayton Rotating Unit (BRU) from 1968 to 1976. Components currently in terrestrial (open cycle) Brayton machines represent TRL 4 for similar uses in 100 kWe-class CBC space systems. Because of the baseline component and subsystem technology maturity, much of the Brayton technology task is focused on issues related to systems integration. A brief description of ongoing technology activities is given.

User manual for NASA Lewis 10 by 10 foot supersonic wind tunnel. Revised

NASA Technical Reports Server (NTRS)

Soeder, Ronald H.

1995-01-01

This manual describes the 10- by 10-Foot Supersonic Wind Tunnel at the NASA Lewis Research Center and provides information for users who wish to conduct experiments in this facility. Tunnel performance operating envelopes of altitude, dynamic pressure, Reynolds number, total pressure, and total temperature as a function of test section Mach number are presented. Operating envelopes are shown for both the aerodynamic (closed) cycle and the propulsion (open) cycle. The tunnel test section Mach number range is 2.0 to 3.5. General support systems, such as air systems, hydraulic system, hydrogen system, fuel system, and Schlieren system, are described. Instrumentation and data processing and acquisition systems are also described. Pretest meeting formats and schedules are outlined. Tunnel user responsibility and personnel safety are also discussed.

Deranged jaw-neck motor control in whiplash-associated disorders.

PubMed

Eriksson, Per-Olof; Zafar, Hamayun; Häggman-Henrikson, Birgitta

2004-02-01

Recent findings of simultaneous and well coordinated head-neck movements during single as well as rhythmic jaw opening-closing tasks has led to the conclusion that 'functional jaw movements' are the result of activation of jaw as well as neck muscles, leading to simultaneous movements in the temporomandibular, atlanto-occipital and cervical spine joints. It can therefore be assumed that disease or injury to any of these joint systems would disturb natural jaw function. To test this hypothesis, amplitudes, temporal coordination, and spatiotemporal consistency of concomitant mandibular and head-neck movements during single maximal jaw opening-closing tasks were analysed in 25 individuals suffering from whiplash-associated disorders (WAD) using optoelectronic movement recording technique. In addition, the relative durations for which the head position was equal to, leading ahead of, or lagging behind the mandibular position during the entire jaw opening-closing cycle were determined. Compared with healthy individuals, the WAD group showed smaller amplitudes, and changed temporal coordination between mandibular and head-neck movements. No divergence from healthy individuals was found for the spatiotemporal consistency or for the analysis during the entire jaw opening-closing cycle. These findings in the WAD group of a 'faulty', but yet consistent, jaw-neck behavior may reflect a basic importance of linked control of the jaw and neck sensory-motor systems. In conclusion, the present results suggest that neck injury is associated with deranged control of mandibular and head-neck movements during jaw opening-closing tasks, and therefore might compromise natural jaw function.

Eruption cycles in a basaltic andesite system: insights from numerical modeling

NASA Astrophysics Data System (ADS)

Smekens, J. F.; Clarke, A. B.; De'Michieli Vitturi, M.

2015-12-01

Persistently active explosive volcanoes are characterized by short explosive bursts, which often occur at periodic intervals numerous times per day, spanning years to decades. Many of these systems present relatively evolved compositions (andesite to rhyolite), and their cyclic activity has been the subject of extensive work (e.g., Soufriere Hills Volcano, Montserrat). However, the same periodic behavior can also be observed at open systems of more mafic compositions, such as Semeru in Indonesia or Karymsky in Kamchatka for example. In this work, we use DOMEFLOW, a 1D transient numerical model of magma ascent, to identify the conditions that lead to and control periodic eruptions in basaltic andesite systems, where the viscosity of the liquid phase can be drastically lower. Periodic behavior occurs for a very narrow range of conditions, for which the mass balance between magma flux and open-system gas escape repeatedly generates a viscous plug, pressurizes the magma beneath the plug, and then explosively disrupts it. The characteristic timescale and magnitude of the eruptive cycles are controlled by the overall viscosity of the magmatic mixture, with higher viscosities leading to longer cycles and lower flow rates at the top of the conduit. Cyclic eruptions in basaltic andesite systems are observed for higher crystal contents, smaller conduit radii, and over a wider range of chamber pressures than the andesitic system, all of which are the direct consequence of a decrease in viscosity of the melt phase, and in turn in the intensity of the viscous forces generated by the system. Results suggest that periodicity can exist in more mafic systems with relatively lower chamber pressures than andesite and rhyolite systems, and may explain why more mafic magmas sometimes remain active for decades.

40 CFR 63.5725 - What are the requirements for monitoring and demonstrating continuous compliance?

Code of Federal Regulations, 2014 CFR

2014-07-01

... Pollutants for Boat Manufacturing Demonstrating Compliance for Open Molding Operations Controlled by Add-on... successive cycles of operation to have a valid hour of data. (2) You must have valid data from at least 90... parameter monitoring system and collect emission capture system and add-on control device parameter data at...

40 CFR 63.5725 - What are the requirements for monitoring and demonstrating continuous compliance?

Code of Federal Regulations, 2013 CFR

2013-07-01

... Pollutants for Boat Manufacturing Demonstrating Compliance for Open Molding Operations Controlled by Add-on... successive cycles of operation to have a valid hour of data. (2) You must have valid data from at least 90... parameter monitoring system and collect emission capture system and add-on control device parameter data at...

Development and Analysis of Models for Handling the Refrigerated Containerized Cargoes

NASA Astrophysics Data System (ADS)

Nyrkov, A.; Pavlova, L.; Nikiforov, V.; Sokolov, S.; Budnik, V.

2017-07-01

This paper considers the open multi-channel queuing system, which receives irregular homogeneous or heterogeneous applications with an unlimited flow of standby time. The system is regarded as an example of a container terminal, having conditionally functional sections with a certain duty cycle, which receives an irregular, non-uniform flow of vessels with the resultant intensity.

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

Fuller, L.C.

The ORCENT-II digital computer program will perform calculations at valves-wide-open design conditions, maximum guaranteed rating conditions, and an approximation of part-load conditions for steam turbine cycles supplied with throttle steam characteristic of contemporary light-water reactors. Turbine performance calculations are based on a method published by the General Electric Company. Output includes all information normally shown on a turbine-cycle heat balance diagram. The program is written in FORTRAN IV for the IBM System 360 digital computers at the Oak Ridge National Laboratory.

Survey of Condition Indicators for Condition Monitoring Systems (Open Access)

DTIC Science & Technology

2014-09-29

Hinesburg, Vermont, 05461, USA jz@renewablenrgsystems.com ABSTRACT Currently, the wind energy industry is swiftly changing its maintenance strategy...from schedule based maintenance to predictive based maintenance . Condition monitoring systems (CMS) play an important role in the predictive... maintenance cycle. As condition monitoring systems are being adopted by more and more OEM and O&M service providers from the wind energy industry, it is

Predicting Behavioral Suites From Genetic Profiles: Variation in Mating, Aggression & Exploration in Pouched Rats

DTIC Science & Technology

2014-08-22

reproductive cycling. We measured the cell cytology of vaginal smears taken from cycling and non-cycling females and collected blood samples for...females often have not developed vaginal openings. To this end, we have compared animals from the field (TZ), housed at APOPO (TZ), and lab (US... vaginal opening postnataly. The vaginal opening appears to develop at about the time females reach 1 kg (about 1-1.5 years of age). Systematic

Real Otto and Diesel Engine Cycles.

ERIC Educational Resources Information Center

Giedd, Ronald

1983-01-01

A thermodynamic analysis of the properties of otto/diesel engines during the time they operate with open chambers illustrates applicability of thermodynamics to real systems, demonstrates how delivered power is controlled, and explains the source of air pollution in terms of thermodynamic laws. (Author/JN)

Organizational Effectiveness: Toward an Integrated Model for Schools of Nursing.

ERIC Educational Resources Information Center

Baker, Constance M.; And Others

1997-01-01

Literature review on organizational effectiveness focuses on major assessment models: goal attainment, human relations, open systems, internal processes, culture, and life cycle. A review of studies of nursing school effectiveness is used to present an agenda for nursing research. (SK)

Creating system engineering products with executable models in a model-based engineering environment

NASA Astrophysics Data System (ADS)

Karban, Robert; Dekens, Frank G.; Herzig, Sebastian; Elaasar, Maged; Jankevičius, Nerijus

2016-08-01

Applying systems engineering across the life-cycle results in a number of products built from interdependent sources of information using different kinds of system level analysis. This paper focuses on leveraging the Executable System Engineering Method (ESEM) [1] [2], which automates requirements verification (e.g. power and mass budget margins and duration analysis of operational modes) using executable SysML [3] models. The particular value proposition is to integrate requirements, and executable behavior and performance models for certain types of system level analysis. The models are created with modeling patterns that involve structural, behavioral and parametric diagrams, and are managed by an open source Model Based Engineering Environment (named OpenMBEE [4]). This paper demonstrates how the ESEM is applied in conjunction with OpenMBEE to create key engineering products (e.g. operational concept document) for the Alignment and Phasing System (APS) within the Thirty Meter Telescope (TMT) project [5], which is under development by the TMT International Observatory (TIO) [5].

Energy Conversion Alternatives Study (ECAS), Westinghouse phase 1. Volume 4: Open recuperated and bottomed gas turbine cycles. [performance prediction and energy conversion efficiency of gas turbines in electric power plants (thermodynamic cycles)

NASA Technical Reports Server (NTRS)

Amos, D. J.; Grube, J. E.

1976-01-01

Open-cycle recuperated gas turbine plant with inlet temperatures of 1255 to 1644 K (1800 to 2500 F) and recuperators with effectiveness values of 0, 70, 80 and 90% are considered. A 1644 K (2500 F) gas turbine would have a 33.5% plant efficiency in a simple cycle, 37.6% in a recuperated cycle and 47.6% when combined with a sulfur dioxide bottomer. The distillate burning recuperated plant was calculated to produce electricity at a cost of 8.19 mills/MJ (29.5 mills/kWh). Due to their low capital cost $170 to 200 $/kW, the open cycle gas turbine plant should see duty for peaking and intermediate load duty.

Cogeneration Technology Alternatives Study (CTAS). Volume 1: Summary

NASA Technical Reports Server (NTRS)

Barna, G. J.; Burns, R. K.; Sagerman, G. D.

1980-01-01

Various advanced energy conversion systems that can use coal or coal-derived fuels for industrial cogeneration applications were compared to provide information needed by DOE to establish research and development funding priorities for advanced-technology systems that could significantly advance the use of coal or coal-derived fuels in industrial cogeneration. Steam turbines, diesel engines, open-cycle gas turbines, combined cycles, closed-cycle gas turbines, Stirling engines, phosphoric acid fuel cells, molten carbonate fuel cells, and thermionics were studied with technology advancements appropriate for the 1985-2000 time period. The various advanced systems were compared and evaluated for wide diversity of representative industrial plants on the basis of fuel energy savings, annual energy cost savings, emissions savings, and rate of return on investment as compared with purchasing electricity from a utility and providing process heat with an on-site boiler. Also included in the comparisons and evaluations are results extrapolated to the national level.

Cogeneration Technology Alternatives Study (CTAS). Volume 2: Comparison and evaluation of results

NASA Technical Reports Server (NTRS)

1984-01-01

CTAS compared and evaluated various advanced energy conversion systems that can use coal or coal-derived fuels for industrial cogeneration applications. The principal aim of the study was to provide information needed by DOE to establish research and development (R&D) funding priorities for advanced-technology systems that could significantly advance the use of coal or coal-derived fuels in industrial cogeneration. Steam turbines, diesel engines, open-cycle gas turbines, combined cycles, closed-cycle gas turbines, Stirling engines, phosphoric acid fuel cells, molten carbonate fuel cells, and thermionics were studied with technology advancements appropriate for the 1985-2000 time period. The various advanced systems were compared and evaluated for a wide diversity of representative industrial plants on the basis of fuel energy savings, annual energy cost savings, emissions savings, and rate of return on investment (ROI) as compared with purchasing electricity from a utility and providing process heat with an on-site boiler.

Experimental investigation of starting characteristics and wave propagation from a shallow open cavity and its acoustic emission at supersonic speed

NASA Astrophysics Data System (ADS)

Pandian, S.; Desikan, S. L. N.; Niranjan, Sahoo

2018-01-01

Experiments were carried out on a shallow open cavity (L/D = 5) at a supersonic Mach number (M = 1.8) to understand its transient starting characteristics, wave propagation (inside and outside the cavity) during one vortex shedding cycle, and acoustic emission. Starting characteristics and wave propagation were visualized through time resolved schlieren images, while acoustic emissions were captured through unsteady pressure measurements. Results showed a complex shock system during the starting process which includes characteristics of the bifurcated shock system, shock train, flow separation, and shock wave boundary layer interaction. In one vortex shedding cycle, vortex convection from cavity leading edge to cavity trailing edge was observed. Flow features outside the cavity demonstrated the formation and downstream movement of a λ-shock due to the interaction of shock from the cavity leading edge and shock due to vortex and generation of waves on account of shear layer impingement at the cavity trailing edge. On the other hand, interesting wave structures and its propagation were monitored inside the cavity. In one vortex shedding cycle, two waves such as a reflected compression wave from a cavity leading edge in the previous vortex shedding cycle and a compression wave due to the reflection of Mach wave at the cavity trailing edge corner in the current vortex shedding cycle were visualized. The acoustic emission from the cavity indicated that the 2nd to 4th modes/tones are dominant, whereas the 1st mode contains broadband spectrum. In the present studies, the cavity feedback mechanism was demonstrated through a derived parameter coherence coefficient.

Optimization of a point-focusing, distributed receiver solar thermal electric system

NASA Technical Reports Server (NTRS)

Pons, R. L.

1979-01-01

This paper presents an approach to optimization of a solar concept which employs solar-to-electric power conversion at the focus of parabolic dish concentrators. The optimization procedure is presented through a series of trade studies, which include the results of optical/thermal analyses and individual subsystem trades. Alternate closed-cycle and open-cycle Brayton engines and organic Rankine engines are considered to show the influence of the optimization process, and various storage techniques are evaluated, including batteries, flywheels, and hybrid-engine operation.

Parametric Crowd Generation Software for MS&T Simulations and Training

DTIC Science & Technology

2007-02-20

3 Technology Overview 5 Dynemotion System Components 5 Dynemotion System Architecture 6 Dynemotion-Enabled NPC Brain Cycles 9 Dynemotion API...Contents 10 Development Project Background Information 11 Potential Application and Impact for the DoD 13 Project Objectives, Scope...Methodology 13 Benefits of the Project 13 Project Innovation 14 *l_essons Learned and Open Questions 14 Research and Development Challenges 16

A Disk-Based System for Producing and Distributing Science Products from MODIS

NASA Technical Reports Server (NTRS)

Masuoka, Edward; Wolfe, Robert; Sinno, Scott; Ye Gang; Teague, Michael

2007-01-01

Since beginning operations in 1999, the MODIS Adaptive Processing System (MODAPS) has evolved to take advantage of trends in information technology, such as the falling cost of computing cycles and disk storage and the availability of high quality open-source software (Linux, Apache and Perl), to achieve substantial gains in processing and distribution capacity and throughput while driving down the cost of system operations.

Antagonistic Enzymes in a Biocatalytic pH Feedback System Program Autonomous DNA Hydrogel Life Cycles.

PubMed

Heinen, Laura; Heuser, Thomas; Steinschulte, Alexander; Walther, Andreas

2017-08-09

Enzymes regulate complex functions and active behavior in natural systems and have shown increasing prospect for developing self-regulating soft matter systems. Striving for advanced autonomous hydrogel materials with fully programmable, self-regulated life cycles, we combine two enzymes with an antagonistic pH-modulating effect in a feedback-controlled biocatalytic reaction network (BRN) and couple it to pH-responsive DNA hydrogels to realize hydrogel systems with distinct preprogrammable lag times and lifetimes in closed systems. The BRN enables precise and orthogonal internal temporal control of the "ON" and "OFF" switching times of the temporary gel state by modulation of programmable, nonlinear pH changes. The time scales are tunable by variation of the enzyme concentrations and additional buffer substances. The resulting material system operates in full autonomy after injection of the chemical fuels driving the BRN. The concept may open new applications inherent to DNA hydrogels, for instance, autonomous shape memory behavior for soft robotics. We further foresee general applicability to achieve autonomous life cycles in other pH switchable systems.

Chronic methylphenidate-effects over circadian cycle of young and adult rats submitted to open-field and object recognition tests.

PubMed

Gomes, Karin M; Souza, Renan P; Valvassori, Samira S; Réus, Gislaine Z; Inácio, Cecília G; Martins, Márcio R; Comim, Clarissa M; Quevedo, João

2009-11-01

In this study age-, circadian rhythm- and methylphenidate administration- effect on open field habituation and object recognition were analyzed. Young and adult male Wistar rats were treated with saline or methylphenidate 2.0 mg/kg for 28 days. Experiments were performed during the light and the dark cycle. Locomotor activity was significantly altered by circadian cycle and methylphenidate treatment during the training session and by drug treatment during the testing session. Exploratory activity was significantly modulated by age during the training session and by age and drug treatment during the testing session. Object recognition memory was altered by cycle at the training session; by age 1.5 h later and by cycle and age 24 h after the training session. These results show that methylphenidate treatment was the major modulator factor on open-field test while cycle and age had an important effect on object recognition experiment.

Advanced spacecraft fuel cell systems

NASA Technical Reports Server (NTRS)

Thaller, L. H.

1972-01-01

The development and characteristics of advanced spacecraft fuel cell systems are discussed. The system is designed to operate on low pressure, propulsion grade hydrogen and oxygen. The specific goals are 10,000 hours of operation with refurbishment, 20 pounds per kilowatt at a sustained power of 7 KW, and 21 KW peaking capability for durations of two hours. The system rejects waste heat to the spacecraft cooling system at power levels up to 7 KW. At higher powers, the system automatically transfers to open cycle operation with overboard steam venting.

A Preliminary Exploration of Operating Models of Second Cycle/Research Led Open Education Involving Industry Collaboration

ERIC Educational Resources Information Center

Olsson, Ulf

2014-01-01

Scientists from five Swedish universities were interviewed about open second cycle education. Research groups and scientists collaborate closely with industry, and the selection of scientists for the study was made in relation to an interest in developing technology-enhanced open education, indicated by applications for funding from the Knowledge…

[Bologna process and higher health education in Europe].

PubMed

Decsi, Tamás; Barakonyi, Károly

2006-08-27

Introduction of the two cycles (Bachelor/Master) system represents sensitive aspect of the implementation of the Bologna process into higher health education. The authors used the methods of evidence based medicine to analyse available documents on the implementation of the Bologna process into the education of health sciences. Electronic search in the closed MEDLINE and open Internet databases. Electronic data collection resulted in so-called country reports (n=47) and in professional statements (n=7) of health education bodies. Majority of the country reports (n=26) did not mention at all the peculiar position of health education within the Bologna process. Many country reports stated with (n=8) or without (n=9) explanation that health sciences should be excluded from the introduction of the two educational cycles system. Only 4 country reports discussed future conditions and possibilities of introducing the two cycles system into higher health education; the German country report definitely declared that the two cycles educational system may be introduced also into health education. The seven statements of professional health educational bodies (including an ad hoc committee of the Hungarian medical faculties) did not support the introduction of the two cycles system into health education. The low demand for health professionals with Bachelor (i.e. unfinished) degree was repeatedly mentioned as strong argument for not introducing the two cycles system into health education. It should be noted, however, that the process of introducing the two cycles system has began: recent survey of EUA (European University Association) indicates that in three countries (Denmark, Flanders and Switzerland) the introduction in under current discussion. Among the principles of the Bologna process, the introduction of the two cycles system has not gain acceptance in the higher health education in Europe. However, most documents firmly support the introduction of other elements of the Bologna process (comparable degrees, system of credits, promotion of mobility of students and tutors, quality control, life long learning).

Association of increased S100A8 serum protein with early pregnancy loss.

PubMed

Nair, Rohini R; Khanna, Anuradha; Singh, Kiran

2015-02-01

The contribution of systemic S100A8 protein in menstrual cycle, pregnancy, and early pregnancy loss (EPL) is not known. Altered expression of S100A8 in maternal decidua is associated with recurrent early pregnancy loss. The objective of this study was to investigate the systemic level of S100A8 in different phases of menstrual cycle, different trimester of pregnancy, and in EPL. Level of S100A8 was investigated in serum samples of the subjects through enzyme-linked immunosorbent assay (ELISA). S100A8 levels were elevated during proliferative phase of menstrual cycle. We found no statistical difference in S100A8 level in different trimester of pregnancy. S100A8 level was found to be significantly elevated in patients with EPL. This is the first study evaluating the systemic level of S100A8 predicting its role during menstrual cycle and pregnancy. It opens a new perspective in which S100A8 can be used as a prognostic marker for EPL. © 2014 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

Enhanced absorption cycle computer model

NASA Astrophysics Data System (ADS)

Grossman, G.; Wilk, M.

1993-09-01

Absorption heat pumps have received renewed and increasing attention in the past two decades. The rising cost of electricity has made the particular features of this heat-powered cycle attractive for both residential and industrial applications. Solar-powered absorption chillers, gas-fired domestic heat pumps, and waste-heat-powered industrial temperature boosters are a few of the applications recently subjected to intensive research and development. The absorption heat pump research community has begun to search for both advanced cycles in various multistage configurations and new working fluid combinations with potential for enhanced performance and reliability. The development of working absorption systems has created a need for reliable and effective system simulations. A computer code has been developed for simulation of absorption systems at steady state in a flexible and modular form, making it possible to investigate various cycle configurations with different working fluids. The code is based on unit subroutines containing the governing equations for the system's components and property subroutines containing thermodynamic properties of the working fluids. The user conveys to the computer an image of his cycle by specifying the different subunits and their interconnections. Based on this information, the program calculates the temperature, flow rate, concentration, pressure, and vapor fraction at each state point in the system, and the heat duty at each unit, from which the coefficient of performance (COP) may be determined. This report describes the code and its operation, including improvements introduced into the present version. Simulation results are described for LiBr-H2O triple-effect cycles, LiCl-H2O solar-powered open absorption cycles, and NH3-H2O single-effect and generator-absorber heat exchange cycles. An appendix contains the user's manual.

Ocean thermal gradient hydraulic power plant.

PubMed

Beck, E J

1975-07-25

Solar energy stored in the oceans may be used to generate power by exploiting ploiting thermal gradients. A proposed open-cycle system uses low-pressure steam to elevate vate water, which is then run through a hydraulic turbine to generate power. The device is analogous to an air lift pump.

Life Cycle Assessment of Cooking Fuel Systems in India, China, Kenya, and Ghana

EPA Science Inventory

Daily use of traditional cooking fuels and stoves in India, China, Kenya, and Ghana emits harmful air pollutants that result in over a million premature deaths annually. Reducing pollution from cookstoves is a key priority, as emissions from traditional cookstoves and open fires ...

CONFERENCE ON SYSTEMS APPROACHES TO CURRICULUM AND INSTRUCTION IN THE OPEN-DOOR COLLEGE (UNIVERSITY OF CALIFORNIA, LOS ANGELES, JULY 18-20, 1966).

ERIC Educational Resources Information Center

JOHNSON, BYRON LAMAR

THE SYSTEMS APPROACH TO INSTRUCTION INVOLVES A CAREFUL SPECIFICATION OF LEARNING OBJECTIVES IN BEHAVIORAL AND MEASURABLE FORM, FOLLOWED BY A SUCCESSION OF EVALUATION-REVISION CYCLES IN THE INSTRUCTIONAL PROCESS, UNTIL NEW STUDENTS EXPOSED TO THE PROCESS ACHIEVE THE DESIRED OBJECTIVES. SEVEN MAJOR PAPERS WERE PRESENTED AT THE CONFERENCE--(1) THE…

Air Evaporation closed cycle water recovery technology - Advanced energy saving designs

NASA Technical Reports Server (NTRS)

Morasko, Gwyndolyn; Putnam, David F.; Bagdigian, Robert

1986-01-01

The Air Evaporation water recovery system is a visible candidate for Space Station application. A four-man Air Evaporation open cycle system has been successfully demonstrated for waste water recovery in manned chamber tests. The design improvements described in this paper greatly enhance the system operation and energy efficiency of the air evaporation process. A state-of-the-art wick feed design which results in reduced logistics requirements is presented. In addition, several design concepts that incorporate regenerative features to minimize the energy input to the system are discussed. These include a recuperative heat exchanger, a heat pump for energy transfer to the air heater, and solar collectors for evaporative heat. The addition of the energy recovery devices will result in an energy reduction of more than 80 percent over the systems used in earlier manned chamber tests.

Biological factors of natural and artificial ecosystems stable (unstable) functioning

NASA Astrophysics Data System (ADS)

Pechurkin, Nikolai S.

The problem of sustainable development of humanity on Earth and the problem of supporting human life in space have the same scientific and methodological bases. The key to solve both problems is a long term maintenance of balanced material cycle. As a whole, natural or artificial ecosystems are to be more closed than open, but their elements (links of systems) are to be substantially open in interactions with each other. Prolonged stable interactions of different links have to have unique joint results - closed material cycling or biotic turnover. It is necessary to include, at least, three types of main links into any system to support real material cycling: producers, consumers, reducers. Producer links are now under studies in many laboratories. It is evident that the higher productivity of link, the lower link stability. Especially, it concerns with parasite impact to plants. As usual, artificial ecosystems are more simple (incomplete) than natural ecosystems, sometimes, they have not enough links for prolonged stable functioning. For example, life support system for space flight can be incomplete in consumer link, having only some crew persons, instead of interacting populations of consumers. As for reducer link, it is necessary to "organize" a special coordinated work of microbial biocenoses to fulfill proper cycling. Possible evolution of links, their self development is a matter of special attention for the maintenance of prolonged stable functioning. It's the most danger for systems with populations of quickly reproducing, so-called, R - strategists, according to symbols of logistic equation. From another side, quick reproduction of R - strategists is able to increase artificial ecosystems and their links functioning. After some damages of system, R - strategist's link can be quickly "self repaired" up to level of normal functioning. Some experimental data of this kind and mathematical models are to be discussed in the paper. This work is supported by grant, Yenissey, 07-04-96806

Energy Conversion Alternatives Study (ECAS)

NASA Technical Reports Server (NTRS)

1977-01-01

ECAS compared various advanced energy conversion systems that can use coal or coal-derived fuels for baseload electric power generation. It was conducted in two phases. Phase 1 consisted of parametric studies. From these results, 11 concepts were selected for further study in Phase 2. For each of the Phase 2 systems and a common set of ground rules, performance, cost, environmental intrusion, and natural resource requirements were estimated. In addition, the contractors defined the state of the associated technology, identified the advances required, prepared preliminary research and development plans, and assessed other factors that would affect the implementation of each type of powerplant. The systems studied in Phase 2 include steam systems with atmospheric- and pressurized-fluidized-bed boilers; combined cycle gas turbine/steam systems with integrated gasifiers or fired by a semiclean, coal derived fuel; a potassium/steam system with a pressurized-fluidized-bed boiler; a closed-cycle gas turbine/organic system with a high-temperature, atmospheric-fluidized-bed furnace; a direct-coal-fired, open- cycle magnetohydrodynamic/steam system; and a molten-carbonate fuel cell/steam system with an integrated gasifier. The sensitivity of the results to changes in the ground rules and the impact of uncertainties in capital cost estimates were also examined.

Explosive dome eruptions modulated by periodic gas-driven inflation

USGS Publications Warehouse

Johnson, Jeffrey B.; Lyons, John; Andrews, B. J.; Lees, J.M.

2014-01-01

Volcan Santiaguito (Guatemala) “breathes” with extraordinary regularity as the edifice's conduit system accumulates free gas, which periodically vents to the atmosphere. Periodic pressurization controls explosion timing, which nearly always occurs at peak inflation, as detected with tiltmeters. Tilt cycles in January 2012 reveal regular 26 ± 6 min inflation/deflation cycles corresponding to at least ~101 kg/s of gas fluxing the system. Very long period (VLP) earthquakes presage explosions and occur during cycles when inflation rates are most rapid. VLPs locate ~300 m below the vent and indicate mobilization of volatiles, which ascend at ~50 m/s. Rapid gas ascent feeds pyroclast-laden eruptions lasting several minutes and rising to ~1 km. VLPs are not observed during less rapid inflation episodes; instead, gas vents passively through the conduit producing no infrasound and no explosion. These observations intimate that steady gas exsolution and accumulation in shallow reservoirs may drive inflation cycles at open-vent silicic volcanoes.

Open cycle traveling wave thermoacoustics: mean temperature difference at the regenerator interface.

PubMed

Weiland, Nathan T; Zinn, Ben T

2003-11-01

In an open cycle traveling wave thermoacoustic engine, the hot heat exchanger is replaced by a steady flow of hot gas into the regenerator to provide the thermal energy input to the engine. The steady-state operation of such a device requires that a potentially large mean temperature difference exist between the incoming gas and the solid material at the regenerator's hot side, due in part to isentropic gas oscillations in the open space adjacent to the regenerator. The magnitude of this temperature difference will have a significant effect on the efficiencies of these open cycle devices. To help assess the feasibility of such thermoacoustic engines, a numerical model is developed that predicts the dependence of the mean temperature difference upon the important design and operating parameters of the open cycle thermoacoustic engine, including the acoustic pressure, mean mass flow rate, acoustic phase angles, and conductive heat loss. Using this model, it is also shown that the temperature difference at the regenerator interface is approximately proportional to the sum of the acoustic power output and the conductive heat loss at this location.

Theory and Tests of Two-Phase Turbines

NASA Technical Reports Server (NTRS)

Elliott, D. G.

1986-01-01

New turbines open possibility of new types of power cycles. Report describes theoretical analysis and experimental testing of two-phase impulse turbines. Such turbines open possibility of new types of power cycles operating with extremely wet mixtures of steam and water, organic fluids, or immiscible liquids and gases. Possible applications are geothermal power, waste-heat recovery, refrigerant expansion, solar conversion, transportation, and engine-bottoming cycles.

Developing a data life cycle for carbon and greenhouse gas measurements: challenges, experiences and visions

NASA Astrophysics Data System (ADS)

Kutsch, W. L.

2015-12-01

Environmental research infrastructures and big data integration networks require common data policies, standardized workflows and sophisticated e-infrastructure to optimise the data life cycle. This presentation summarizes the experiences in developing the data life cycle for the Integrated Carbon Observation System (ICOS), a European Research Infrastructure. It will also outline challenges that still exist and visions for future development. As many other environmental research infrastructures ICOS RI built on a large number of distributed observational or experimental sites. Data from these sites are transferred to Thematic Centres and quality checked, processed and integrated there. Dissemination will be managed by the ICOS Carbon Portal. This complex data life cycle has been defined in detail by developing protocols and assigning responsibilities. Since data will be shared under an open access policy there is a strong need for common data citation tracking systems that allow data providers to identify downstream usage of their data so as to prove their importance and show the impact to stakeholders and the public. More challenges arise from interoperating with other infrastructures or providing data for global integration projects as done e.g. in the framework of GEOSS or in global integration approaches such as fluxnet or SOCAt. Here, common metadata systems are the key solutions for data detection and harvesting. The metadata characterises data, services, users and ICT resources (including sensors and detectors). Risks may arise when data of high and low quality are mixed during this process or unexperienced data scientists without detailed knowledge on the data aquisition derive scientific theories through statistical analyses. The vision of fully open data availability is expressed in a recent GEO flagship initiative that will address important issues needed to build a connected and interoperable global network for carbon cycle and greenhouse gas observations and aims to meet the most urgent needs for integration between different information sources and methodologies, between different regional networks and from data providers to users.

Cyclic reconstruction of 4D retinal blood flow with pulse synchronization

NASA Astrophysics Data System (ADS)

Schmoll, Tilman; Lasser, Theo; Leitgeb, Rainer A.

2009-02-01

Doppler OCT systems allow nowadays to visualize quantitative and qualitative angiographic maps of retinal tissue. We equipped the instrument with a pulse oximeter and recorded the pulse synchronously with the resonant Doppler flow data. Recombination of tomograms according to the heart beat cycles yields full volumes for each cycle instant. We believe such multi-dimensional functional information and the ability to monitor dynamic processes over time to open exciting perspectives that ultimately contribute to a better understanding of retinal physiology and patho-physiology in-vivo.

Can cycling safety be improved by opening all unidirectional cycle paths for cycle traffic in both directions? A theoretical examination of available literature and data.

PubMed

Methorst, Rob; Schepers, Paul; Kamminga, Jaap; Zeegers, Theo; Fishman, Elliot

2017-08-01

Many studies have found bicycle-motor vehicle crashes to be more likely on bidirectional cycle paths than on unidirectional cycle paths because drivers do not expect cyclists riding at the right side of the road. In this paper we discuss the hypothesis that opening all unidirectional cycle paths for cycle traffic in both directions prevent this lack of expectancy and accordingly improves cycling safety. A new national standard requires careful consideration because a reversal is difficult once cyclists are used to their new freedom of route choice. We therefore explored the hypothesis using available data, research, and theories. The results show that of the length of cycle paths along distributor roads in the Netherlands, 72% is bidirectional. If drivers would become used to cyclists riding at the left side of the road, this result raises the question of why bidirectional cycle paths in the Netherlands still have a poor safety record compared to unidirectional cycle paths. Moreover, our exploration suggested that bidirectional cycle paths have additional safety problems. It increases the complexity of unsignalized intersections because drivers have to scan more directions in a short period of time. Moreover, there are some indications that the likelihood of frontal crashes between cyclists increases. We reject the hypothesis that opening all unidirectional cycle paths for cycle traffic in both directions will improve cycle safety. We recommend more attention for mitigating measures given the widespread application of bidirectional cycle paths in the Netherlands. Copyright © 2016 Elsevier Ltd. All rights reserved.

Choline in the treatment of rapid-cycling bipolar disorder: clinical and neurochemical findings in lithium-treated patients.

PubMed

Stoll, A L; Sachs, G S; Cohen, B M; Lafer, B; Christensen, J D; Renshaw, P F

1996-09-01

This study examined choline augmentation of lithium for rapid-cycling bipolar disorder. Choline bitartrate was given openly to 6 consecutive lithium-treated outpatients with rapid-cycling bipolar disorder. Five patients also underwent brain proton magnetic resonance spectroscopy. Five of 6 rapid-cycling patients had a substantial reduction in manic symptoms, and 4 patients had a marked reduction in all mood symptoms during choline therapy. The patients who responded to choline all exhibited a substantial rise in the basal ganglia concentration of choline-containing compounds. Choline was well tolerated in all cases. Choline, in the presence of lithium, was a safe and effective treatment for 4 of 6 rapid-cycling patients in our series. A hypothesis is suggested to explain both lithium refractoriness in patients with bipolar disorder and the action of choline in mania, which involves the interaction between phosphatidylinositol and phosphatidylcholine second-messenger systems.

Food webs of two intermittently open estuaries receiving 15N-enriched sewage effluent

NASA Astrophysics Data System (ADS)

Hadwen, Wade L.; Arthington, Angela H.

2007-01-01

Carbon and nitrogen stable isotope signatures were used to assess the response of food webs to sewage effluent discharged into two small intermittently open estuaries in northern New South Wales, Australia. One of these systems, Tallows Creek, has a history of direct sewage inputs, whilst the other, Belongil Creek, receives wastewater via an extensive wetland treatment system. The food webs of both systems were driven by algal sources of carbon, reflecting high autotrophic productivity in response to the nutrients entering the system from sewage effluent. All aquatic biota collected from Tallows Creek had significantly enriched δ15N signatures relative to their conspecifics from Belongil Creek, indicating that sewage nitrogen had been assimilated and transferred throughout the Tallows Creek food web. These δ15N values were higher than those reported from studies in permanently open estuaries receiving sewage effluent. We suggest that these enriched signatures and the transfer of nitrogen throughout the entire food web reflect differences in hydrology and associated nitrogen cycling processes between permanently open and intermittently open estuaries. Although all organisms in Tallows Creek were generally 15N-enriched, isotopically light (less 15N-enriched) individuals of estuary perchlet ( Ambassis marianus) and sea mullet ( Mugil cephalus) were also collected. These individuals were most likely recent immigrants into Tallows Creek, as this system had only recently been opened to the ocean. This isotopic discrimination between resident (enriched) and immigrant (significantly less enriched) individuals can provide information on fish movement patterns and the role of heavily polluted intermittently open estuaries in supporting commercially and recreationally valuable estuarine species.

Cell cycle dynamics in a response/signalling feedback system with a gap.

PubMed

Gong, Xue; Buckalew, Richard; Young, Todd; Boczko, Erik

2014-01-01

We consider a dynamical model of cell cycles of n cells in a culture in which cells in one specific phase (S for signalling) of the cell cycle produce chemical agents that influence the growth/cell cycle progression of cells in another phase (R for responsive). In the case that the feedback is negative, it is known that subpopulations of cells tend to become clustered in the cell cycle; while for a positive feedback, all the cells tend to become synchronized. In this paper, we suppose that there is a gap between the two phases. The gap can be thought of as modelling the physical reality of a time delay in the production and action of the signalling agents. We completely analyse the dynamics of this system when the cells are arranged into two cell cycle clusters. We also consider the stability of certain important periodic solutions in which clusters of cells have a cyclic arrangement and there are just enough clusters to allow interactions between them. We find that the inclusion of a small gap does not greatly alter the global dynamics of the system; there are still large open sets of parameters for which clustered solutions are stable. Thus, we add to the evidence that clustering can be a robust phenomenon in biological systems. However, the gap does effect the system by enhancing the stability of the stable clustered solutions. We explain this phenomenon in terms of contraction rates (Floquet exponents) in various invariant subspaces of the system. We conclude that in systems for which these models are reasonable, a delay in signalling is advantageous to the emergence of clustering.

Consideration of black carbon and primary organic carbon emissions in life-cycle analysis of Greenhouse gas emissions of vehicle systems and fuels.

PubMed

Cai, Hao; Wang, Michael Q

2014-10-21

The climate impact assessment of vehicle/fuel systems may be incomplete without considering short-lived climate forcers of black carbon (BC) and primary organic carbon (POC). We quantified life-cycle BC and POC emissions of a large variety of vehicle/fuel systems with an expanded Greenhouse gases, Regulated Emissions, and Energy use in Transportation model developed at Argonne National Laboratory. Life-cycle BC and POC emissions have small impacts on life-cycle greenhouse gas (GHG) emissions of gasoline, diesel, and other fuel vehicles, but would add 34, 16, and 16 g CO2 equivalent (CO2e)/mile, or 125, 56, and 56 g CO2e/mile with the 100 or 20 year Global Warming Potentials of BC and POC emissions, respectively, for vehicles fueled with corn stover-, willow tree-, and Brazilian sugarcane-derived ethanol, mostly due to BC- and POC-intensive biomass-fired boilers in cellulosic and sugarcane ethanol plants for steam and electricity production, biomass open burning in sugarcane fields, and diesel-powered agricultural equipment for biomass feedstock production/harvest. As a result, life-cycle GHG emission reduction potentials of these ethanol types, though still significant, are reduced from those without considering BC and POC emissions. These findings, together with a newly expanded GREET version, help quantify the previously unknown impacts of BC and POC emissions on life-cycle GHG emissions of U.S. vehicle/fuel systems.

Design and development of a community carbon cycle benchmarking system for CMIP5 models

NASA Astrophysics Data System (ADS)

Mu, M.; Hoffman, F. M.; Lawrence, D. M.; Riley, W. J.; Keppel-Aleks, G.; Randerson, J. T.

2013-12-01

Benchmarking has been widely used to assess the ability of atmosphere, ocean, sea ice, and land surface models to capture the spatial and temporal variability of observations during the historical period. For the carbon cycle and terrestrial ecosystems, the design and development of an open-source community platform has been an important goal as part of the International Land Model Benchmarking (ILAMB) project. Here we designed and developed a software system that enables the user to specify the models, benchmarks, and scoring systems so that results can be tailored to specific model intercomparison projects. We used this system to evaluate the performance of CMIP5 Earth system models (ESMs). Our scoring system used information from four different aspects of climate, including the climatological mean spatial pattern of gridded surface variables, seasonal cycle dynamics, the amplitude of interannual variability, and long-term decadal trends. We used this system to evaluate burned area, global biomass stocks, net ecosystem exchange, gross primary production, and ecosystem respiration from CMIP5 historical simulations. Initial results indicated that the multi-model mean often performed better than many of the individual models for most of the observational constraints.

Adopting Open Source Software to Address Software Risks during the Scientific Data Life Cycle

NASA Astrophysics Data System (ADS)

Vinay, S.; Downs, R. R.

2012-12-01

Software enables the creation, management, storage, distribution, discovery, and use of scientific data throughout the data lifecycle. However, the capabilities offered by software also present risks for the stewardship of scientific data, since future access to digital data is dependent on the use of software. From operating systems to applications for analyzing data, the dependence of data on software presents challenges for the stewardship of scientific data. Adopting open source software provides opportunities to address some of the proprietary risks of data dependence on software. For example, in some cases, open source software can be deployed to avoid licensing restrictions for using, modifying, and transferring proprietary software. The availability of the source code of open source software also enables the inclusion of modifications, which may be contributed by various community members who are addressing similar issues. Likewise, an active community that is maintaining open source software can be a valuable source of help, providing an opportunity to collaborate to address common issues facing adopters. As part of the effort to meet the challenges of software dependence for scientific data stewardship, risks from software dependence have been identified that exist during various times of the data lifecycle. The identification of these risks should enable the development of plans for mitigating software dependencies, where applicable, using open source software, and to improve understanding of software dependency risks for scientific data and how they can be reduced during the data life cycle.

PATHWAYS OF MERCURY EVASION FROM CONTAMINATED WETLANDS: A GLOBALLY IMPORTANT SOURCE OF ATMOSPHERIC MERCURY?

EPA Science Inventory

Mercury (Hg) is a globally occurring pollutant that bioaccumulates and persists in the environment. The global Hg cycle is highly dependant on air/water exchange, as it is one of the primary pathways to deliver Hg to the atmosphere. Although open water systems appear to be net...

Numerical simulation of the actuation system for the ALDF's propulsion control valve. [Aircraft Landing Dynamics Facility

NASA Technical Reports Server (NTRS)

Korte, John J.

1990-01-01

A numerical simulation of the actuation system for the propulsion control valve (PCV) of the NASA Langley Aircraft Landing Dynamics Facility was developed during the preliminary design of the PCV and used throughout the entire project. The simulation is based on a predictive model of the PCV which is used to evaluate and design the actuation system. The PCV controls a 1.7 million-pound thrust water jet used in propelling a 108,000-pound test carriage. The PCV can open and close in 0.300 second and deliver over 9,000 gallons of water per sec at pressures up to 3150 psi. The numerical simulation results are used to predict transient performance and valve opening characteristics, specify the hydraulic control system, define transient loadings on components, and evaluate failure modes. The mathematical model used for numerically simulating the mechanical fluid power system is described, and numerical results are demonstrated for a typical opening and closing cycle of the PCV. A summary is then given on how the model is used in the design process.

Operational experience of the OC-OTEC experiments at NELH

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

Link, H

1989-02-01

The Solar Energy Research Institute, under funding and program direction from the US Department of Energy, has been operating a small-scale test apparatus to investigate key components of open- cycle ocean thermal energy conversion (OC-OTEC). The apparatus started operations in October 1987 and continues to provide valuable information on heat-and mass-transfer processes in evaporators and condensers, gas sorption processes as seawater is depressurized and repressurized, and control and instrumentation characteristics of open-cycle systems. Although other test facilities have been used to study some of these interactions, this is the largest apparatus of its kind to use seawater since Georges Claude`smore » efforts in 1926. The information obtained from experiments conducted in this apparatus is being used to design a larger scale experiment in which a positive net power production is expected to be demonstrated for the first time with OC-OTEC. This paper describes the apparatus, the major tests conducted during its first 18 months of operation, and the experience gained in OC-OTEC system operation. 13 refs., 8 figs.« less

Open-system coral ages reveal persistent suborbital sea-level cycles.

PubMed

Thompson, William G; Goldstein, Steven L

2005-04-15

Sea level is a sensitive index of global climate that has been linked to Earth's orbital variations, with a minimum periodicity of about 21,000 years. Although there is ample evidence for climate oscillations that are too frequent to be explained by orbital forcing, suborbital-frequency sea-level change has been difficult to resolve, primarily because of problems with uranium/thorium coral dating. Here we use a new approach that corrects coral ages for the frequently observed open-system behavior of uranium-series nuclides, substantially improving the resolution of sea-level reconstruction. This curve reveals persistent sea-level oscillations that are too frequent to be explained exclusively by orbital forcing.

Characterization of open and closed volcanic systems in Indonesia and Mexico using InSAR time series

NASA Astrophysics Data System (ADS)

Chaussard, E.; Amelung, F.; Aoki, Y.

2013-08-01

use 2007-2011 Advanced Land Observing Satellite (ALOS) data to perform an arc-wide interferometric synthetic aperture radar (InSAR) time series survey of the Trans-Mexican Volcanic Belt (TMVB) and to study time-dependent ground deformation of four Indonesian volcanoes selected following the 2007-2009 study of Chaussard and Amelung (2012). Our objectives are to examine whether arc volcanoes exhibit long-term edifice-wide cyclic deformation patterns that can be used to characterize open and closed volcanic systems and to better constrain in which cases precursory inflation is expected. We reveal deformation cycles at both regularly active and previously inactive Indonesian volcanoes, but we do not detect deformation in the TMVB, reflecting a lower activity level. We identify three types of relationships between deformation and activity: inflation prior to eruption and associated with or followed by deflation (Kerinci and Sinabung), inflation without eruption and followed by slow deflation (Agung), and eruption without precursory deformation (Merapi, Colima, and Popocatépetl; at Merapi, no significant deformation is detected even during eruption). The first two cases correspond to closed volcanic systems and suggest that the traditional model of magmatic systems and eruptive cycles do apply to andesitic volcanoes (i.e., inflation and deflation episodes associated with magma accumulation or volatile exsolution in a crustal reservoir followed by eruptions or in situ cooling). In contrast, the last case corresponds to open volcanic systems where no significant pressurization of the magmatic reservoirs is taking place prior to eruptions and thus no long-term edifice-wide ground deformation can be detected. We discuss these results in terms of InSAR's potential for forecasting volcanic unrest.

Performance and economic risk evaluation of dispersed solar thermal power systems by Monte Carlo simulation

NASA Technical Reports Server (NTRS)

Manvi, R.; Fujita, T.

1978-01-01

A preliminary comparative evaluation of dispersed solar thermal power plants utilizing advanced technologies available in 1985-2000 time frame is under way at JPL. The solar power plants of 50 KWe to 10 MWe size are equipped with two axis tracking parabolic dish concentrator systems operating at temperatures in excess of 1000 F. The energy conversion schemes under consideration include advanced steam, open and closed cycle gas turbines, stirling, and combined cycle. The energy storage systems include advanced batteries, liquid metal, and chemical. This paper outlines a simple methodology for a probabilistic assessment of such systems. Sources of uncertainty in the development of advanced systems are identified, and a computer Monte Carlo simulation is exercised to permit an analysis of the tradeoffs of the risk of failure versus the potential for large gains. Frequency distribution of energy cost for several alternatives are presented.

Energy Conversion Alternatives Study (ECAS), General Electric Phase 1. Volume 1: Executive summary. [using coal or coal derived fuels

NASA Technical Reports Server (NTRS)

Corman, J. C.

1976-01-01

A data base for the comparison of advanced energy conversion systems for utility applications using coal or coal-derived fuels was developed. Estimates of power plant performance (efficiency), capital cost, cost of electricity, natural resource requirements, and environmental intrusion characteristics were made for ten advanced conversion systems. Emphasis was on the energy conversion system in the context of a base loaded utility power plant. All power plant concepts were premised on meeting emission standard requirements. A steam power plant (3500 psig, 1000 F) with a conventional coal-burning furnace-boiler was analyzed as a basis for comparison. Combined cycle gas/steam turbine system results indicated competitive efficiency and a lower cost of electricity compared to the reference steam plant. The Open-Cycle MHD system results indicated the potential for significantly higher efficiency than the reference steam plant but with a higher cost of electricity.

Open quantum generalisation of Hopfield neural networks

NASA Astrophysics Data System (ADS)

Rotondo, P.; Marcuzzi, M.; Garrahan, J. P.; Lesanovsky, I.; Müller, M.

2018-03-01

We propose a new framework to understand how quantum effects may impact on the dynamics of neural networks. We implement the dynamics of neural networks in terms of Markovian open quantum systems, which allows us to treat thermal and quantum coherent effects on the same footing. In particular, we propose an open quantum generalisation of the Hopfield neural network, the simplest toy model of associative memory. We determine its phase diagram and show that quantum fluctuations give rise to a qualitatively new non-equilibrium phase. This novel phase is characterised by limit cycles corresponding to high-dimensional stationary manifolds that may be regarded as a generalisation of storage patterns to the quantum domain.

A variational method for analyzing limit cycle oscillations in stochastic hybrid systems

NASA Astrophysics Data System (ADS)

Bressloff, Paul C.; MacLaurin, James

2018-06-01

Many systems in biology can be modeled through ordinary differential equations, which are piece-wise continuous, and switch between different states according to a Markov jump process known as a stochastic hybrid system or piecewise deterministic Markov process (PDMP). In the fast switching limit, the dynamics converges to a deterministic ODE. In this paper, we develop a phase reduction method for stochastic hybrid systems that support a stable limit cycle in the deterministic limit. A classic example is the Morris-Lecar model of a neuron, where the switching Markov process is the number of open ion channels and the continuous process is the membrane voltage. We outline a variational principle for the phase reduction, yielding an exact analytic expression for the resulting phase dynamics. We demonstrate that this decomposition is accurate over timescales that are exponential in the switching rate ɛ-1 . That is, we show that for a constant C, the probability that the expected time to leave an O(a) neighborhood of the limit cycle is less than T scales as T exp (-C a /ɛ ) .

42: An Open-Source Simulation Tool for Study and Design of Spacecraft Attitude Control Systems

NASA Technical Reports Server (NTRS)

Stoneking, Eric

2018-01-01

Simulation is an important tool in the analysis and design of spacecraft attitude control systems. The speaker will discuss the simulation tool, called simply 42, that he has developed over the years to support his own work as an engineer in the Attitude Control Systems Engineering Branch at NASA Goddard Space Flight Center. 42 was intended from the outset to be high-fidelity and powerful, but also fast and easy to use. 42 is publicly available as open source since 2014. The speaker will describe some of 42's models and features, and discuss its applicability to studies ranging from early concept studies through the design cycle, integration, and operations. He will outline 42's architecture and share some thoughts on simulation development as a long-term project.

ADVANCED NUCLEAR FUEL CYCLE EFFECTS ON THE TREATMENT OF UNCERTAINTY IN THE LONG-TERM ASSESSMENT OF GEOLOGIC DISPOSAL SYSTEMS - EBS INPUT

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

Sutton, M; Blink, J A; Greenberg, H R

2012-04-25

The Used Fuel Disposition (UFD) Campaign within the Department of Energy's Office of Nuclear Energy (DOE-NE) Fuel Cycle Technology (FCT) program has been tasked with investigating the disposal of the nation's spent nuclear fuel (SNF) and high-level nuclear waste (HLW) for a range of potential waste forms and geologic environments. The planning, construction, and operation of a nuclear disposal facility is a long-term process that involves engineered barriers that are tailored to both the geologic environment and the waste forms being emplaced. The UFD Campaign is considering a range of fuel cycles that in turn produce a range of wastemore » forms. The UFD Campaign is also considering a range of geologic media. These ranges could be thought of as adding uncertainty to what the disposal facility design will ultimately be; however, it may be preferable to thinking about the ranges as adding flexibility to design of a disposal facility. For example, as the overall DOE-NE program and industrial actions result in the fuel cycles that will produce waste to be disposed, and the characteristics of those wastes become clear, the disposal program retains flexibility in both the choice of geologic environment and the specific repository design. Of course, other factors also play a major role, including local and State-level acceptance of the specific site that provides the geologic environment. In contrast, the Yucca Mountain Project (YMP) repository license application (LA) is based on waste forms from an open fuel cycle (PWR and BWR assemblies from an open fuel cycle). These waste forms were about 90% of the total waste, and they were the determining waste form in developing the engineered barrier system (EBS) design for the Yucca Mountain Repository design. About 10% of the repository capacity was reserved for waste from a full recycle fuel cycle in which some actinides were extracted for weapons use, and the remaining fission products and some minor actinides were encapsulated in borosilicate glass. Because the heat load of the glass was much less than the PWR and BWR assemblies, the glass waste form was able to be co-disposed with the open cycle waste, by interspersing glass waste packages among the spent fuel assembly waste packages. In addition, the Yucca Mountain repository was designed to include some research reactor spent fuel and naval reactor spent fuel, within the envelope that was set using the commercial reactor assemblies as the design basis waste form. This milestone report supports Sandia National Laboratory milestone M2FT-12SN0814052, and is intended to be a chapter in that milestone report. The independent technical review of this LLNL milestone was performed at LLNL and is documented in the electronic Information Management (IM) system at LLNL. The objective of this work is to investigate what aspects of quantifying, characterizing, and representing the uncertainty associated with the engineered barrier are affected by implementing different advanced nuclear fuel cycles (e.g., partitioning and transmutation scenarios) together with corresponding designs and thermal constraints.« less

An Analysis of the President’s Budgetary Proposals for Fiscal Year 2006

DTIC Science & Technology

2005-03-01

Domestic Product (Average percentage change from CBO’s baseline) Source: Congressional Budget Office. Notes: The “textbook” growth model is an...Global Insight Closed-Economy Life-Cycle Model Open-Economy Life-Cycle Model Textbook Model Memorandum: Gross National Product Open-Economy Life-Cycle...domestic product in the models . 2. Over time, however, increased investment will enlarge the capital stock, in turn reducing the pretax rate of return and

Opening Pandora's Box: The impact of open system modeling on interpretations of anoxia

NASA Astrophysics Data System (ADS)

Hotinski, Roberta M.; Kump, Lee R.; Najjar, Raymond G.

2000-06-01

The geologic record preserves evidence that vast regions of ancient oceans were once anoxic, with oxygen levels too low to sustain animal life. Because anoxic conditions have been postulated to foster deposition of petroleum source rocks and have been implicated as a kill mechanism in extinction events, the genesis of such anoxia has been an area of intense study. Most previous models of ocean oxygen cycling proposed, however, have either been qualitative or used closed-system approaches. We reexamine the question of anoxia in open-system box models in order to test the applicability of closed-system results over long timescales and find that open and closed-system modeling results may differ significantly on both short and long timescales. We also compare a scenario with basinwide diffuse upwelling (a three-box model) to a model with upwelling concentrated in the Southern Ocean (a four-box model). While a three-box modeling approach shows that only changes in high-latitude convective mixing rate and character of deepwater sources are likely to cause anoxia, four-box model experiments indicate that slowing of thermohaline circulation, a reduction in wind-driven upwelling, and changes in high-latitude export production may also cause dysoxia or anoxia in part of the deep ocean on long timescales. These results suggest that box models must capture the open-system and vertically stratified nature of the ocean to allow meaningful interpretations of long-lived episodes of anoxia.

Enzyme efficiency: An open reaction system perspective

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

Banerjee, Kinshuk, E-mail: kb36@rice.edu; Bhattacharyya, Kamal, E-mail: pchemkb@gmail.com

2015-12-21

A measure of enzyme efficiency is proposed for an open reaction network that, in suitable form, applies to closed systems as well. The idea originates from the description of classical enzyme kinetics in terms of cycles. We derive analytical expressions for the efficiency measure by treating the network not only deterministically but also stochastically. The latter accounts for any significant amount of noise that can be present in biological systems and hence reveals its impact on efficiency. Numerical verification of the results is also performed. It is found that the deterministic equation overestimates the efficiency, the more so for verymore » small system sizes. Roles of various kinetics parameters and system sizes on the efficiency are thoroughly explored and compared with the standard definition k{sub 2}/K{sub M}. Study of substrate fluctuation also indicates an interesting efficiency-accuracy balance.« less

Energy-efficient regenerative liquid desiccant drying process

DOEpatents

Ko, Suk M.; Grodzka, Philomena G.; McCormick, Paul O.

1980-01-01

This invention relates to the use of desiccants in conjunction with an open oop drying cycle and a closed loop drying cycle to reclaim the energy expended in vaporizing moisture in harvested crops. In the closed loop cycle, the drying air is brought into contact with a desiccant after it exits the crop drying bin. Water vapor in the moist air is absorbed by the desiccant, thus reducing the relative humidity of the air. The air is then heated by the used desiccant and returned to the crop bin. During the open loop drying cycle the used desiccant is heated (either fossil or solar energy heat sources may be used) and regenerated at high temperature, driving water vapor from the desiccant. This water vapor is condensed and used to preheat the dilute (wet) desiccant before heat is added from the external source (fossil or solar). The latent heat of vaporization of the moisture removed from the desiccant is reclaimed in this manner. The sensible heat of the regenerated desiccant is utilized in the open loop drying cycle. Also, closed cycle operation implies that no net energy is expended in heating drying air.

Improving the Cybersecurity of U.S. Air Force Military Systems Throughout Their Life Cycles

DTIC Science & Technology

2015-01-01

James D. Powers, Elizabeth Bodine-Baron, Bernard Fox, Lauren Kendrick, Michael H. Powell Report Documentation Page Form ApprovedOMB No. 0704...Rational, Natural, and Open Systems, 3rd ed., Englewood Cliffs, N.J.: Prentice Hall, 1992. 61 Snyder, Don, Bernard Fox, Kristin F. Lynch, Raymond E...Conley, John A. Ausink, Laura Werber , William Shelton, Sarah A. Nowak, Michael R. Thirtle, and Albert A. Robbert, Assessment of the Air Force

Defense AT and L. Volume 39, Number 4. July August 2010

DTIC Science & Technology

2010-07-01

basis in a joint life cycle management review, which is open to all of our stake- holders. Program assessments cover systems engineering, logistics...contacted the JPEO-CBD’s Joint Project Management Office for Chemical Biological Medical Systems to request DoD’s assistance in developing a way for...consequence management and course of action analysis tools. Can you further discuss those warning tools and provide examples of them in action? A When

Efficacy and safety of a transdermal contraceptive system.

PubMed

Smallwood, G H; Meador, M L; Lenihan, J P; Shangold, G A; Fisher, A C; Creasy, G W

2001-11-01

To evaluate the efficacy, cycle control, compliance, and safety of a transdermal contraceptive system that delivers norelgestromin 150 microg and ethinyl estradiol 20 microg daily. In this open-label, 73-center study, 1672 healthy, ovulatory, sexually active women received ORTHO EVRA/EVRA for six (n = 1171) or 13 cycles (n = 501). The treatment regimen for each cycle was three consecutive 7-day patches (21 days) followed by 1 patch-free week. The overall and method-failure probabilities of pregnancy through 13 cycles were 0.7% and 0.4%, respectively. The incidence of breakthrough bleeding was low throughout the study. Perfect compliance (21 consecutive days of dosing, followed by a 7-day drug-free interval; no patch could be worn for more than 7 days) was achieved in 90% of subject cycles; only 1.9% of patches detached completely. Adverse events were typical of hormonal contraception, and most were mild-to-moderate in severity and not treatment limiting. The most common adverse events resulting in discontinuation were application site reactions (1.9%), nausea (1.8%), emotional lability (1.5%), headache (1.1%), and breast discomfort (1.0%). The transdermal contraceptive patch provides effective contraception and cycle control, and is well tolerated. The weekly change schedule for the contraceptive patch is associated with excellent compliance and wearability characteristics.

Airborne particle dispersion to an operating room environment during sliding and hinged door opening.

PubMed

Sadrizadeh, Sasan; Pantelic, Jovan; Sherman, Max; Clark, Jordan; Abouali, Omid

2018-03-08

Operating rooms (ORs) are usually over-pressurized in order to prevent the penetration of contaminated air and the consequent risk of surgical site infection. However, a door-opening can result in the rapid disappearance of pressure and contaminants can then easily penetrate into the surgical zone. Therefore, a broad knowledge and understanding of OR ventilation systems and their protective potential is essential for optimizing the surgical environment. This study investigated the air quality and level of airborne particles during a single and multiple door-opening cycles in an operating room supplied by a turbulent-mixing ventilation system. The exploration was carried out numerically using computational fluid dynamics. Model validation was performed to ensure the validity of the achieved results. The OR was initially over-pressurized by approximately 15Pa, relative to the adjacent corridors. Both sliding and hinged doors were simulated and compared. Penetration of bacteria carrying particles from the corridors to the OR can be successfully restricted by using a positive-pressure system. However, the results clearly indicate that frequent door opening can interfere with airflow ventilation systems, alter the pressure gradient, and increase the infection risk for the patient undergoing surgical intervention. Door-opening disturbs the airflow field and could result in containment failure. Copyright © 2018 The Authors. Published by Elsevier Ltd.. All rights reserved.

Requirements for Xenon International

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

Hayes, James C.; Ely, James H.; Haas, Derek A.

2015-12-30

This document defines the requirements for the new Xenon International radioxenon system. The output of this project will be a Pacific Northwest National Laboratory (PNNL) developed prototype and a manufacturer-developed production prototype. The two prototypes are intended to be as close to matching as possible; this will be facilitated by overlapping development cycles and open communication between PNNL and the manufacturer.

Modeling and Simulation of a Parametrically Resonant Micromirror With Duty-Cycled Excitation.

PubMed

Shahid, Wajiha; Qiu, Zhen; Duan, Xiyu; Li, Haijun; Wang, Thomas D; Oldham, Kenn R

2014-12-01

High frequency large scanning angle electrostatically actuated microelectromechanical systems (MEMS) mirrors are used in a variety of applications involving fast optical scanning. A 1-D parametrically resonant torsional micromirror for use in biomedical imaging is analyzed here with respect to operation by duty-cycled square waves. Duty-cycled square wave excitation can have significant advantages for practical mirror regulation and/or control. The mirror's nonlinear dynamics under such excitation is analyzed in a Hill's equation form. This form is used to predict stability regions (the voltage-frequency relationship) of parametric resonance behavior over large scanning angles using iterative approximations for nonlinear capacitance behavior of the mirror. Numerical simulations are also performed to obtain the mirror's frequency response over several voltages for various duty cycles. Frequency sweeps, stability results, and duty cycle trends from both analytical and simulation methods are compared with experimental results. Both analytical models and simulations show good agreement with experimental results over the range of duty cycled excitations tested. This paper discusses the implications of changing amplitude and phase with duty cycle for robust open-loop operation and future closed-loop operating strategies.

ENVI-PV: An Interactive Web Client for Multi-Criteria Life Cycle Assessment of Photovoltaic Systems Worldwide

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

Perez-Lopez, Paula; Gschwind, Benoit; Blanc, Philippe

Solar photovoltaics (PV) is the second largest source of new capacity among renewable energies. The worldwide capacity encompassed 135 GW in 2013 and is estimated to increase to 1721 GW in 2030 and 4674 GW in 2050, according to a prospective high-renewable scenario. To achieve this production level while minimizing environmental impacts, decision makers must have access to environmental performance data that reflect their high spatial variability accurately. We propose ENVI-PV (http://viewer.webservice-energy.org/project_iea), a new interactive tool that provides maps and screening level data, based on weighted average supply chains, for the environmental performance of common PV technologies. Environmental impacts ofmore » PV systems are evaluated according to a life cycle assessment approach. ENVI-PV was developed using a state-of-the-art interoperable and open standard Web Service framework from the Open Geospatial Consortium (OGC). It combines the latest life cycle inventories, published in 2015 by the International Energy Agency (IEA) under the Photovoltaic Power Systems Program (PVPS) Task 12, and some inventories previously published from Ecoinvent v2.2 database with solar irradiation estimates computed from the worldwide NASA SSE database. ENVI-PV is the first tool to propose a worldwide coverage of environmental performance of PV systems using a multi-criteria assessment. The user can compare the PV environmental performance to the environmental footprint of country electricity mixes. ENVI-PV is designed as an environmental interactive tool to generate PV technological options and evaluate their performance in different spatial and techno-economic contexts. Its potential applications are illustrated in this paper with several examples.« less

Life cycle assessment-driven selection of industrial ecology strategies.

PubMed

Ardente, Fulvio; Cellura, Maurizio; Lo Brano, Valerio; Mistretta, Marina

2010-01-01

The paper presents an application of the Life-Cycle Assessment (LCA) to the planning and environmental management of an “eco-industrial cluster.” A feasibility study of industrial symbiosis in southern Italy is carried out, where interlinked companies share subproducts and scraps, services, structures, and plants to reduce the related environmental impact. In particular, the research focuses on new recycling solutions to create open recycling loops in which plastic subproducts and scraps are transferred to external production systems. The main environmental benefits are the reduction of resource depletion, air emissions, and landfilled wastes. The proposed strategies are also economically viable and they suggest cost abatement for the involved companies. This research shows the need for a multidisciplinary approach to data processing and to complexity managing of the investigated systems. In this context, life-cycle thinking is required to be promoted throughout the economy, as well to be as a part of all decisions on products and other criteria such as functionality, health, and safety. The Life-Cycle Assessment approach can be assumed as a methodology for influencing decision makers to make sustainable choices.

75 FR 36648 - Blue Ribbon Commission on America's Nuclear Future, Reactor and Fuel Cycle Technologies Subcommittee

Federal Register 2010, 2011, 2012, 2013, 2014

2010-06-28

... DEPARTMENT OF ENERGY Blue Ribbon Commission on America's Nuclear Future, Reactor and Fuel Cycle Technologies Subcommittee AGENCY: Office of Nuclear Energy, DOE. ACTION: Notice of open meeting correction. On June 21, 2010, the Department of Energy published a notice announcing an open meeting of the Reactor...

Development and Implementation of Dynamic Scripts to Execute Cycled WRF/GSI Forecasts

NASA Technical Reports Server (NTRS)

Zavodsky, Bradley; Srikishen, Jayanthi; Berndt, Emily; Li, Quanli; Watson, Leela

2014-01-01

Automating the coupling of data assimilation (DA) and modeling systems is a unique challenge in the numerical weather prediction (NWP) research community. In recent years, the Development Testbed Center (DTC) has released well-documented tools such as the Weather Research and Forecasting (WRF) model and the Gridpoint Statistical Interpolation (GSI) DA system that can be easily downloaded, installed, and run by researchers on their local systems. However, developing a coupled system in which the various preprocessing, DA, model, and postprocessing capabilities are all integrated can be labor-intensive if one has little experience with any of these individual systems. Additionally, operational modeling entities generally have specific coupling methodologies that can take time to understand and develop code to implement properly. To better enable collaborating researchers to perform modeling and DA experiments with GSI, the Short-term Prediction Research and Transition (SPoRT) Center has developed a set of Perl scripts that couple GSI and WRF in a cycling methodology consistent with the use of real-time, regional observation data from the National Centers for Environmental Prediction (NCEP)/Environmental Modeling Center (EMC). Because Perl is open source, the code can be easily downloaded and executed regardless of the user's native shell environment. This paper will provide a description of this open-source code and descriptions of a number of the use cases that have been performed by SPoRT collaborators using the scripts on different computing systems.

New R-SiC extends service life in kiln furniture

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

Sonntag, A.

1997-11-01

Silicon carbide kiln furniture systems are an essential part of modern high-temperature technology. SiC ceramics have exceptional high-temperature stability and thermal shock resistance., They show no plastic deformation (creep) under mechanical load and maintain their geometry after each high-temperature cycle. Therefore, various new kiln systems with light and open setting patterns can be realized where more fired goods can be produced with less kiln furniture ballast and within shorter firing cycles. The fast-firing technology of porcelain is an opportunity for new SiC kiln furniture ceramics. The new SiC ceramic systems available include: (1) recrystallized SiC (R-SiC); (2) silicon-infiltrated reaction-bonded SiCmore » (SiSiC); and (3) nitride-bonded SiC (NSiC). The new SiC ceramics have an important production criterion in common. They show practically no shrinkage during production. This is important for the manufacture of large shapes, such as beams, rollers and setter plates, as well as tailored geometries that allow light and open kiln furniture construction. Because of the extraordinarily high thermal shock resistance, high strength and high-temperature creep stability of these SiC ceramics, delicate and precise kiln furniture configurations have been introduced. One application is the fast firing of tableware with automatic setting robots.« less

Robust Criterion for the Existence of Nonhyperbolic Ergodic Measures

NASA Astrophysics Data System (ADS)

Bochi, Jairo; Bonatti, Christian; Díaz, Lorenzo J.

2016-06-01

We give explicit C 1-open conditions that ensure that a diffeomorphism possesses a nonhyperbolic ergodic measure with positive entropy. Actually, our criterion provides the existence of a partially hyperbolic compact set with one-dimensional center and positive topological entropy on which the center Lyapunov exponent vanishes uniformly. The conditions of the criterion are met on a C 1-dense and open subset of the set of diffeomorphisms having a robust cycle. As a corollary, there exists a C 1-open and dense subset of the set of non-Anosov robustly transitive diffeomorphisms consisting of systems with nonhyperbolic ergodic measures with positive entropy. The criterion is based on a notion of a blender defined dynamically in terms of strict invariance of a family of discs.

Building an Open Source Framework for Integrated Catchment Modeling

NASA Astrophysics Data System (ADS)

Jagers, B.; Meijers, E.; Villars, M.

2015-12-01

In order to develop effective strategies and associated policies for environmental management, we need to understand the dynamics of the natural system as a whole and the human role therein. This understanding is gained by comparing our mental model of the world with observations from the field. However, to properly understand the system we should look at dynamics of water, sediments, water quality, and ecology throughout the whole system from catchment to coast both at the surface and in the subsurface. Numerical models are indispensable in helping us understand the interactions of the overall system, but we need to be able to update and adjust them to improve our understanding and test our hypotheses. To support researchers around the world with this challenging task we started a few years ago with the development of a new open source modeling environment DeltaShell that integrates distributed hydrological models with 1D, 2D, and 3D hydraulic models including generic components for the tracking of sediment, water quality, and ecological quantities throughout the hydrological cycle composed of the aforementioned components. The open source approach combined with a modular approach based on open standards, which allow for easy adjustment and expansion as demands and knowledge grow, provides an ideal starting point for addressing challenging integrated environmental questions.

Continuous field measurements of δD in water vapor by open-path Fourier transform infrared spectrometry

NASA Astrophysics Data System (ADS)

Wang, Wei; Liu, Wenqing; Zhang, Tianshu

2012-12-01

The stable isotopes in atmospheric water vapor contain rich information on the hydrologic cycles and gaseous exchange processes between biosphere and atmosphere. About one-week field experiment was conducted to continuously measure the isotope composition of water vapor in ambient air using an open-path FTIR system. Mixing ratios of H2 16O and HD16O were measured simultaneously. Analysis of water vapor isotopes revealed that the variations of H2 16O and HD16O were highly related. Mixing ratios of both isotopes varied considerably on a daily timescale or between days, with no obvious diurnal cycle, whereas the deuterium isotopic [delta]D showed clear diel cycle. The results illustrated that the correlation between [delta]D and H2O mixing ratio was relatively weak, which was also demonstrated by the Keeling plot analysis with the whole data. Yet the further Keeling analysis on a daily timescale displayed more obvious linear relationship between [delta]D and the total H2O concentration. All daily isotopic values of evapotranspiration source were obtained, with the range between -113.93±10.25‰ and -245.63±17.61‰ over the observation period.

Environmental and economic assessment methods for waste management decision-support: possibilities and limitations.

PubMed

Finnveden, Göran; Björklund, Anna; Moberg, Asa; Ekvall, Tomas

2007-06-01

A large number of methods and approaches that can be used for supporting waste management decisions at different levels in society have been developed. In this paper an overview of methods is provided and preliminary guidelines for the choice of methods are presented. The methods introduced include: Environmental Impact Assessment, Strategic Environmental Assessment, Life Cycle Assessment, Cost-Benefit Analysis, Cost-effectiveness Analysis, Life-cycle Costing, Risk Assessment, Material Flow Accounting, Substance Flow Analysis, Energy Analysis, Exergy Analysis, Entropy Analysis, Environmental Management Systems, and Environmental Auditing. The characteristics used are the types of impacts included, the objects under study and whether the method is procedural or analytical. The different methods can be described as systems analysis methods. Waste management systems thinking is receiving increasing attention. This is, for example, evidenced by the suggested thematic strategy on waste by the European Commission where life-cycle analysis and life-cycle thinking get prominent positions. Indeed, life-cycle analyses have been shown to provide policy-relevant and consistent results. However, it is also clear that the studies will always be open to criticism since they are simplifications of reality and include uncertainties. This is something all systems analysis methods have in common. Assumptions can be challenged and it may be difficult to generalize from case studies to policies. This suggests that if decisions are going to be made, they are likely to be made on a less than perfect basis.

A Digital Knowledge Preservation Platform for Environmental Sciences

NASA Astrophysics Data System (ADS)

Aguilar Gómez, Fernando; de Lucas, Jesús Marco; Pertinez, Esther; Palacio, Aida; Perez, David

2017-04-01

The Digital Knowledge Preservation Platform is the evolution of a pilot project for Open Data supporting the full research data life cycle. It is currently being evolved at IFCA (Instituto de Física de Cantabria) as a combination of different open tools that have been extended: DMPTool (https://dmptool.org/) with pilot semantics features (RDF export, parameters definition), INVENIO (http://invenio-software.org/ ) customized version to integrate the entire research data life cycle and Jupyter (http://jupyter.org/) as processing tool and reproducibility environment. This complete platform aims to provide an integrated environment for research data management following the FAIR+R principles: -Findable: The Web portal based on Invenio provides a search engine and all elements including metadata to make them easily findable. -Accessible: Both data and software are available online with internal PIDs and DOIs (provided by Datacite). -Interoperable: Datasets can be combined to perform new analysis. The OAI-PMH standard is also integrated. -Re-usable: different licenses types and embargo periods can be defined. -+Reproducible: directly integrated with cloud computing resources. The deployment of the entire system over a Cloud framework helps to build a dynamic and scalable solution, not only for managing open datasets but also as a useful tool for the final user, who is able to directly process and analyse the open data. In parallel, the direct use of semantics and metadata is being explored and integrated in the framework. Ontologies, being a knowledge representation, can contribute to define the elements and relationships of the research data life cycle, including DMP, datasets, software, etc. The first advantage of developing an ontology of a knowledge domain is that they provide a common vocabulary hierarchy (i.e. a conceptual schema) that can be used and standardized by all the agents interested in the domain (either humans or machines). This way of using ontologies is one of the basis of the Semantic Web, where ontologies are set to play a key role in establishing a common terminology between agents. To develop the ontology we are using a graphical tool called Protégé. Protégé is a graphical ontology-development tool which supports a rich knowledge model and it is open-source and freely available. However in order to process and manage the ontology from the web framework, we are using Semantic MediaWiki, which is able to process queries. Semantic MediaWiki is an extension of MediaWiki where we can do semantic search and export data in RDF and CSV format. This system is used as a testbed for the potential use of semantics in a more general environment. This Digital Knowledge Preservation Platform is very closed related to INDIGO-DataCloud project (https://www.indigo-datacloud.eu) since the same data life cycle approach is taking into account (Planning, Collect, Curate, Analyze, Publish, Preserve). INDIGO-DataCloud solutions will be able to support all the different elements in the system, as we showed in the last Research Data Alliance Plenary. This presentation will show the different elements on the system and how they work, as well as the roadmap of their continuous integration.

A Novel Fuel/Reactor Cycle to Implement the 300 Years Nuclear Waste Policy Approach - 12377

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

Carelli, M.D.; Franceschini, F.; Lahoda, E.J.

2012-07-01

A thorium-based fuel cycle system can effectively burn the currently accumulated commercial used nuclear fuel and move to a sustainable equilibrium where the actinide levels in the high level waste are low enough to yield a radiotoxicity after 300 years lower than that of the equivalent uranium ore. The second step of the Westinghouse approach to solving the waste 'problem' has been completed. The thorium fuel cycle has indeed the potential of burning the legacy TRU and achieve the waste objective proposed. Initial evaluations have been started for the third step, development and selection of appropriate reactors. Indications are thatmore » the probability of show-stoppers is rather remote. It is, therefore, believed that development of the thorium cycle and associated technologies will provide a permanent solution to the waste management. Westinghouse is open to the widest collaboration to make this a reality. (authors)« less

pyhector: A Python interface for the simple climate model Hector

DOE PAGES

Willner, Sven N.; Hartin, Corinne; Gieseke, Robert

2017-04-01

Here, pyhector is a Python interface for the simple climate model Hector (Hartin et al. 2015) developed in C++. Simple climate models like Hector can, for instance, be used in the analysis of scenarios within integrated assessment models like GCAM1, in the emulation of complex climate models, and in uncertainty analyses. Hector is an open-source, object oriented, simple global climate carbon cycle model. Its carbon cycle consists of a one pool atmosphere, three terrestrial pools which can be broken down into finer biomes or regions, and four carbon pools in the ocean component. The terrestrial carbon cycle includes primary productionmore » and respiration fluxes. The ocean carbon cycle circulates carbon via a simplified thermohaline circulation, calculating air-sea fluxes as well as the marine carbonate system. The model input is time series of greenhouse gas emissions; as example scenarios for these the Pyhector package contains the Representative Concentration Pathways (RCPs)2.« less

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

Willner, Sven N.; Hartin, Corinne; Gieseke, Robert

Here, pyhector is a Python interface for the simple climate model Hector (Hartin et al. 2015) developed in C++. Simple climate models like Hector can, for instance, be used in the analysis of scenarios within integrated assessment models like GCAM1, in the emulation of complex climate models, and in uncertainty analyses. Hector is an open-source, object oriented, simple global climate carbon cycle model. Its carbon cycle consists of a one pool atmosphere, three terrestrial pools which can be broken down into finer biomes or regions, and four carbon pools in the ocean component. The terrestrial carbon cycle includes primary productionmore » and respiration fluxes. The ocean carbon cycle circulates carbon via a simplified thermohaline circulation, calculating air-sea fluxes as well as the marine carbonate system. The model input is time series of greenhouse gas emissions; as example scenarios for these the Pyhector package contains the Representative Concentration Pathways (RCPs)2.« less

Distributed computer system enhances productivity for SRB joint optimization

NASA Technical Reports Server (NTRS)

Rogers, James L., Jr.; Young, Katherine C.; Barthelemy, Jean-Francois M.

1987-01-01

Initial calculations of a redesign of the solid rocket booster joint that failed during the shuttle tragedy showed that the design had a weight penalty associated with it. Optimization techniques were to be applied to determine if there was any way to reduce the weight while keeping the joint opening closed and limiting the stresses. To allow engineers to examine as many alternatives as possible, a system was developed consisting of existing software that coupled structural analysis with optimization which would execute on a network of computer workstations. To increase turnaround, this system took advantage of the parallelism offered by the finite difference technique of computing gradients to allow several workstations to contribute to the solution of the problem simultaneously. The resulting system reduced the amount of time to complete one optimization cycle from two hours to one-half hour with a potential of reducing it to 15 minutes. The current distributed system, which contains numerous extensions, requires one hour turnaround per optimization cycle. This would take four hours for the sequential system.

Blue guardian: an open architecture for rapid ISR demonstration

NASA Astrophysics Data System (ADS)

Barrett, Donald A.; Borntrager, Luke A.; Green, David M.

2016-05-01

Throughout the Department of Defense (DoD), acquisition, platform integration, and life cycle costs for weapons systems have continued to rise. Although Open Architecture (OA) interface standards are one of the primary methods being used to reduce these costs, the Air Force Rapid Capabilities Office (AFRCO) has extended the OA concept and chartered the Open Mission System (OMS) initiative with industry to develop and demonstrate a consensus-based, non-proprietary, OA standard for integrating subsystems and services into airborne platforms. The new OMS standard provides the capability to decouple vendor-specific sensors, payloads, and service implementations from platform-specific architectures and is still in the early stages of maturation and demonstration. The Air Force Research Laboratory (AFRL) - Sensors Directorate has developed the Blue Guardian program to demonstrate advanced sensing technology utilizing open architectures in operationally relevant environments. Over the past year, Blue Guardian has developed a platform architecture using the Air Force's OMS reference architecture and conducted a ground and flight test program of multiple payload combinations. Systems tested included a vendor-unique variety of Full Motion Video (FMV) systems, a Wide Area Motion Imagery (WAMI) system, a multi-mode radar system, processing and database functions, multiple decompression algorithms, multiple communications systems, and a suite of software tools. Initial results of the Blue Guardian program show the promise of OA to DoD acquisitions, especially for Intelligence, Surveillance and Reconnaissance (ISR) payload applications. Specifically, the OMS reference architecture was extremely useful in reducing the cost and time required for integrating new systems.

OpenDanubia - An integrated, modular simulation system to support regional water resource management

NASA Astrophysics Data System (ADS)

Muerth, M.; Waldmann, D.; Heinzeller, C.; Hennicker, R.; Mauser, W.

2012-04-01

The already completed, multi-disciplinary research project GLOWA-Danube has developed a regional scale, integrated modeling system, which was successfully applied on the 77,000 km2 Upper Danube basin to investigate the impact of Global Change on both the natural and anthropogenic water cycle. At the end of the last project phase, the integrated modeling system was transferred into the open source project OpenDanubia, which now provides both the core system as well as all major model components to the general public. First, this will enable decision makers from government, business and management to use OpenDanubia as a tool for proactive management of water resources in the context of global change. Secondly, the model framework to support integrated simulations and all simulation models developed for OpenDanubia in the scope of GLOWA-Danube are further available for future developments and research questions. OpenDanubia allows for the investigation of water-related scenarios considering different ecological and economic aspects to support both scientists and policy makers to design policies for sustainable environmental management. OpenDanubia is designed as a framework-based, distributed system. The model system couples spatially distributed physical and socio-economic process during run-time, taking into account their mutual influence. To simulate the potential future impacts of Global Change on agriculture, industrial production, water supply, households and tourism businesses, so-called deep actor models are implemented in OpenDanubia. All important water-related fluxes and storages in the natural environment are implemented in OpenDanubia as spatially explicit, process-based modules. This includes the land surface water and energy balance, dynamic plant water uptake, ground water recharge and flow as well as river routing and reservoirs. Although the complete system is relatively demanding on data requirements and hardware requirements, the modular structure and the generic core system (Core Framework, Actor Framework) allows the application in new regions and the selection of a reduced number of modules for simulation. As part of the Open Source Initiative in GLOWA-Danube (opendanubia.glowa-danube.de) a comprehensive documentation for the system installation was created and both the program code of the framework and of all major components is licensed under the GNU General Public License. In addition, some helpful programs and scripts necessary for the operation and processing of input and result data sets are provided.

Transdermal granisetron versus palonosetron for prevention of chemotherapy-induced nausea and vomiting following moderately emetogenic chemotherapy: a multicenter, randomized, open-label, cross-over, active-controlled, and phase IV study.

PubMed

Seol, Young Mi; Kim, Hyo Jeong; Choi, Young Jin; Lee, Eun Mi; Kim, Yang Soo; Oh, Sung Yong; Koh, Su Jin; Baek, Jin Ho; Lee, Won Sik; Joo, Young Don; Lee, Hyun Gi; Yun, Eun Young; Chung, Joo Seop

2016-02-01

Palonosetron is the second-generation 5-hydroxytryptamine 3 receptor antagonist (5-HT3RA) that has shown better efficacy than the first-generation 5-HT3RA for prevention of chemotherapy-induced nausea and vomiting (CINV) in patients receiving moderately emetogenic chemotherapy (MEC). Granisetron transdermal delivery system (GTDS), a novel transdermal formulation, was developed to deliver granisetron continuously over 7 days. This study compared the efficacy and tolerability of the GTDS to palonosetron for the control of CINV following MEC. A total of 196 patients were randomized to GP or PG group. In this multicenter, randomized, open-label, cross-over, active-controlled, Phase IV study, GP group was assigned to receive transdermal granisetron (one GTDS patch, 7 days) in the first chemotherapy cycle, palonosetron (iv 0.25 mg/day, 1 days) in the second chemotherapy cycle before receiving MEC, and PG group was assigned to receive palonosetron in the first cycle and GTDS in the second cycle. Primary endpoint was the percentage of chemotherapy cycles achieving complete response (CR; defined as no emetic episodes and no rescue medication use) during the acute phase (0-24 h in post-chemotherapy; non-inferiority comparison with palonosetron). Total 333 cycles (165 in GTDS and 168 in palonosetron) were included in the per protocol analysis. The GTDS cycles showed non-inferiority to palonosetron cycles during the acute phase: CR was achieved by 124 (75.2 %) patients in the GTDS cycles and 134 (79.8 %) patients in the palonosetron cycles (treatment difference, -4.6 %; 95 % confidence interval, -13.6-4.4). There was no significant difference in CR rate during acute phase after the end of the first and second chemotherapy cycle between GP and PG group (p = 0.405, p = 0.074). Patients' satisfaction, assessed using Functional Living Index-Emesis (FLI-E), GTDS cycle were higher than those of palonosetron cycle in GP group (FLI-E score; median 1549.5 in GTDS cycle, median 1670.0 in palonosetron cycle). Both treatments were well tolerated and safe. Transdermal granisetron is a good alternative therapeutic option to palonosetron for preventing CINV after MEC.

A Structured Approach for Reviewing Architecture Documentation

DTIC Science & Technology

2009-12-01

as those found in ISO 12207 [ ISO /IEC 12207 :2008] (for software engineering), ISO 15288 [ ISO /IEC 15288:2008] (for systems engineering), the Rational...Open Distributed Processing - Reference Model: Foundations ( ISO /IEC 10746-2). 1996. [ ISO /IEC 12207 :2008] International Organization for...Standardization & International Electrotechnical Commission. Sys- tems and software engineering – Software life cycle processes ( ISO /IEC 12207 ). 2008. [ ISO

Structural map of Kaposi sarcoma-associated herpesvirus RNA provides clues to molecular interactions | Center for Cancer Research

Cancer.gov

Scientists from CCR have generated a comprehensive structural map of Kaposi sarcoma-associated herpesvirus polyadenylated nuclear (PAN) RNA, a long non-coding RNA that helps the virus evade detection by its host’s immune system. The findings open new oppportunites to study the life cycle of this cancer-causing virus.  Learn more...

IRIS: Supporting & Managing the Research Life-Cycle

ERIC Educational Resources Information Center

Bollini, Andrea; Mennielli, Michele; Mornati, Susanna; Palmer, David T.

2016-01-01

IRIS is a new Current Research Information System (CRIS) developed by Cineca to upgrade and replace two previous solutions that have been used by Italian universities in the last 10 years. At the end of 2015, sixty-three Italian institutions are using IRIS. One of the main components of IRIS is DSpace-CRIS, an open source solution that can also be…

Cogeneration Technology Alternatives Study (CTAS). Volume 1: Summary report

NASA Technical Reports Server (NTRS)

Gerlaugh, H. E.; Hall, E. W.; Brown, D. H.; Priestley, R. R.; Knightly, W. F.

1980-01-01

Large savings can be made in industry by cogenerating electric power and process heat in single energy conversion systems rather than separately in utility plants and in process boilers. About fifty industrial processes from the largest energy consuming sectors were used as a basis for matching a similar number of energy conversion systems that are considered as candidates which can be made available by the 1985 to 2000 time period. The sectors considered included food, textiles, lumber, paper, chemicals, petroleum, glass, and primary metals. The energy conversion systems included steam and gas turbines, diesels, thermionics, stirling, closed-cycle and steam injected gas turbines, and fuel cells. Fuels considered were coal, both coal and petroleum-based residual and distillate liquid fuels, and low Btu gas obtained through the on-site gasification of coal. An attempt was made to use consistent assumptions and a consistent set of ground rules for determining performance and cost in individual plants and on a national level. It was found that: (1) atmospheric and pressurized fluidized bed steam turbine systems were the most attractive of the direct coal-fired systems; and (2) open-cycle gas turbines with heat recovery steam generators and combined-cycles with NO(x) emission reduction and moderately increased firing temperatures were the most attractive of the coal-derived liquid-fired systems.

Reliability of Ceramic Column Grid Array Interconnect Packages Under Extreme Temperatures

NASA Technical Reports Server (NTRS)

Ramesham, Rajeshuni

2011-01-01

A paper describes advanced ceramic column grid array (CCGA) packaging interconnects technology test objects that were subjected to extreme temperature thermal cycles. CCGA interconnect electronic package printed wiring boards (PWBs) of polyimide were assembled, inspected nondestructively, and, subsequently, subjected to ex - treme-temperature thermal cycling to assess reliability for future deep-space, short- and long-term, extreme-temperature missions. The test hardware consisted of two CCGA717 packages with each package divided into four daisy-chained sections, for a total of eight daisy chains to be monitored. The package is 33 33 mm with a 27 27 array of 80%/20% Pb/Sn columns on a 1.27-mm pitch. The change in resistance of the daisy-chained CCGA interconnects was measured as a function of the increasing number of thermal cycles. Several catastrophic failures were observed after 137 extreme-temperature thermal cycles, as per electrical resistance measurements, and then the tests were continued through 1,058 thermal cycles to corroborate and understand the test results. X-ray and optical inspection have been made after thermal cycling. Optical inspections were also conducted on the CCGA vs. thermal cycles. The optical inspections were conclusive; the x-ray images were not. Process qualification and assembly is required to optimize the CCGA assembly, which is very clear from the x-rays. Six daisy chains were open out of seven daisy chains, as per experimental test data reported. The daisy chains are open during the cold cycle, and then recover during the hot cycle, though some of them also opened during the hot thermal cycle..

A global model of carbon-nutrient interactions

NASA Technical Reports Server (NTRS)

Moore, Berrien, III; Gildea, Patricia; Vorosmarty, Charles; Mellilo, Jerry M.; Peterson, Bruce J.

1985-01-01

The global biogeochemical model presented has two primary objectives. First, it characterizes natural elemental cycles and their linkages for the four elements significant to Earth's biota: C, N, S, and P. Second, it describes changes in these cycles due to human activity. Global nutrient cycles were studied within the drainage basins of several major world rivers on each continent. The initial study region was the Mississippi drainage basin, concentrating on carbon and nitrogen. The model first establishes the nutrient budgets of the undisturbed ecosystems in a study region. It then uses a data set of land use histories for that region to document the changes in these budgets due to land uses. Nutrient movement was followed over time (1800 to 1980) for 30 ecosystems and 10 land use categories. A geographically referenced ecological information system (GREIS) was developed to manage the digital global data bases of 0.5 x 0.5 grid cells needed to run the model: potential vegetation, drainage basins, precipitation, runoff, contemporary land cover, and FAO soil maps of the world. The results show the contributions of land use categories to river nutrient loads on a continental scale; shifts in nutrient cycling patterns from closed, steady state systems to mobile transient or open, steady state systems; soil organic matter depletion patterns in U.S. agricultural lands; changing nutrient ratios due to land use changes; and the effect of using heavy fertilizer on aquatic systems.

Irreversible thermodynamics of open chemical networks. I. Emergent cycles and broken conservation laws

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

Polettini, Matteo, E-mail: matteo.polettini@uni.lu; Esposito, Massimiliano

In this paper and Paper II, we outline a general framework for the thermodynamic description of open chemical reaction networks, with special regard to metabolic networks regulating cellular physiology and biochemical functions. We first introduce closed networks “in a box”, whose thermodynamics is subjected to strict physical constraints: the mass-action law, elementarity of processes, and detailed balance. We further digress on the role of solvents and on the seemingly unacknowledged property of network independence of free energy landscapes. We then open the system by assuming that the concentrations of certain substrate species (the chemostats) are fixed, whether because promptly regulatedmore » by the environment via contact with reservoirs, or because nearly constant in a time window. As a result, the system is driven out of equilibrium. A rich algebraic and topological structure ensues in the network of internal species: Emergent irreversible cycles are associated with nonvanishing affinities, whose symmetries are dictated by the breakage of conservation laws. These central results are resumed in the relation a + b = s{sup Y} between the number of fundamental affinities a, that of broken conservation laws b and the number of chemostats s{sup Y}. We decompose the steady state entropy production rate in terms of fundamental fluxes and affinities in the spirit of Schnakenberg's theory of network thermodynamics, paving the way for the forthcoming treatment of the linear regime, of efficiency and tight coupling, of free energy transduction, and of thermodynamic constraints for network reconstruction.« less

Irreversible thermodynamics of open chemical networks. I. Emergent cycles and broken conservation laws.

PubMed

Polettini, Matteo; Esposito, Massimiliano

2014-07-14

In this paper and Paper II, we outline a general framework for the thermodynamic description of open chemical reaction networks, with special regard to metabolic networks regulating cellular physiology and biochemical functions. We first introduce closed networks "in a box", whose thermodynamics is subjected to strict physical constraints: the mass-action law, elementarity of processes, and detailed balance. We further digress on the role of solvents and on the seemingly unacknowledged property of network independence of free energy landscapes. We then open the system by assuming that the concentrations of certain substrate species (the chemostats) are fixed, whether because promptly regulated by the environment via contact with reservoirs, or because nearly constant in a time window. As a result, the system is driven out of equilibrium. A rich algebraic and topological structure ensues in the network of internal species: Emergent irreversible cycles are associated with nonvanishing affinities, whose symmetries are dictated by the breakage of conservation laws. These central results are resumed in the relation a + b = s(Y) between the number of fundamental affinities a, that of broken conservation laws b and the number of chemostats s(Y). We decompose the steady state entropy production rate in terms of fundamental fluxes and affinities in the spirit of Schnakenberg's theory of network thermodynamics, paving the way for the forthcoming treatment of the linear regime, of efficiency and tight coupling, of free energy transduction, and of thermodynamic constraints for network reconstruction.

Irreversible thermodynamics of open chemical networks. I. Emergent cycles and broken conservation laws

NASA Astrophysics Data System (ADS)

Polettini, Matteo; Esposito, Massimiliano

2014-07-01

In this paper and Paper II, we outline a general framework for the thermodynamic description of open chemical reaction networks, with special regard to metabolic networks regulating cellular physiology and biochemical functions. We first introduce closed networks "in a box", whose thermodynamics is subjected to strict physical constraints: the mass-action law, elementarity of processes, and detailed balance. We further digress on the role of solvents and on the seemingly unacknowledged property of network independence of free energy landscapes. We then open the system by assuming that the concentrations of certain substrate species (the chemostats) are fixed, whether because promptly regulated by the environment via contact with reservoirs, or because nearly constant in a time window. As a result, the system is driven out of equilibrium. A rich algebraic and topological structure ensues in the network of internal species: Emergent irreversible cycles are associated with nonvanishing affinities, whose symmetries are dictated by the breakage of conservation laws. These central results are resumed in the relation a + b = sY between the number of fundamental affinities a, that of broken conservation laws b and the number of chemostats sY. We decompose the steady state entropy production rate in terms of fundamental fluxes and affinities in the spirit of Schnakenberg's theory of network thermodynamics, paving the way for the forthcoming treatment of the linear regime, of efficiency and tight coupling, of free energy transduction, and of thermodynamic constraints for network reconstruction.

High rate, long cycle life battery electrode materials with an open framework structure

DOEpatents

Wessells, Colin; Huggins, Robert; Cui, Yi; Pasta, Mauro

2015-02-10

A battery includes a cathode, an anode, and an aqueous electrolyte disposed between the cathode and the anode and including a cation A. At least one of the cathode and the anode includes an electrode material having an open framework crystal structure into which the cation A is reversibly inserted during operation of the battery. The battery has a reference specific capacity when cycled at a reference rate, and at least 75% of the reference specific capacity is retained when the battery is cycled at 10 times the reference rate.

Destroyer Engineered Operating Cycle (DDEOC), System Maintenance Analysis DDG-37 Class, Salt Water Circulating System SMA 37-106-256, Review of Experience

DTIC Science & Technology

1978-07-01

horizontally mounted, single-end suction, single- stage centrifugal pumps. The rotating elements are mounted on the shaft of the driving motor, and the pump...annual open-and-inspect requirement for MIP E-17/296-21, MRC 21 A14V A. Industrial Facility Improvements -- None IMA Improvements -- None Intergrated ...Circulating Pump, Warren Pumps, Inc., NAVSHIPS 347-3146, January 1959. 4. Technical Manual - Horizontal Close-Co!;pled Pumps Sea (Salt) Water

Turbo-generator control with variable valve actuation

DOEpatents

Vuk, Carl T [Denver, IA

2011-02-22

An internal combustion engine incorporating a turbo-generator and one or more variably activated exhaust valves. The exhaust valves are adapted to variably release exhaust gases from a combustion cylinder during a combustion cycle to an exhaust system. The turbo-generator is adapted to receive exhaust gases from the exhaust system and rotationally harness energy therefrom to produce electrical power. A controller is adapted to command the exhaust valve to variably open in response to a desired output for the turbo-generator.

Transient and sustained elementary flux mode networks on a catalytic string-based chemical evolution model.

PubMed

Pereira, José A

2014-08-01

Theoretical models designed to test the metabolism-first hypothesis for prebiotic evolution have yield strong indications about the hypothesis validity but could sometimes use a more extensive identification between model objects and real objects towards a more meaningful interpretation of results. In an attempt to go in that direction, the string-based model SSE ("steady state evolution") was developed, where abstract molecules (strings) and catalytic interaction rules are based on some of the most important features of carbon compounds in biological chemistry. The system is open with a random inflow and outflow of strings but also with a permanent string food source. Although specific catalysis is a key aspect of the model, used to define reaction rules, the focus is on energetics rather than kinetics. Standard energy change tables were constructed and used with standard formation reactions to track energy flows through the interpretation of equilibrium constant values. Detection of metabolic networks on the reaction system was done with elementary flux mode (EFM) analysis. The combination of these model design and analysis options enabled obtaining metabolic and catalytic networks showing several central features of biological metabolism, some more clearly than in previous models: metabolic networks with stepwise synthesis, energy coupling, catalysts regulation, SN2 coupling, redox coupling, intermediate cycling, coupled inverse pathways (metabolic cycling), autocatalytic cycles and catalytic cascades. The results strongly suggest that the main biological metabolism features, including the genotype-phenotype interpretation, are caused by the principles of catalytic systems and are prior to modern genetic systems principles. It also gives further theoretical support to the thesis that the basic features of biologic metabolism are a consequence of the time evolution of a random catalyst search working on an open system with a permanent food source. The importance of the food source characteristics and evolutionary possibilities are discussed. Copyright © 2014 Elsevier Ireland Ltd. All rights reserved.

Modeling and Simulation of a Parametrically Resonant Micromirror With Duty-Cycled Excitation

PubMed Central

Shahid, Wajiha; Qiu, Zhen; Duan, Xiyu; Li, Haijun; Wang, Thomas D.; Oldham, Kenn R.

2014-01-01

High frequency large scanning angle electrostatically actuated microelectromechanical systems (MEMS) mirrors are used in a variety of applications involving fast optical scanning. A 1-D parametrically resonant torsional micromirror for use in biomedical imaging is analyzed here with respect to operation by duty-cycled square waves. Duty-cycled square wave excitation can have significant advantages for practical mirror regulation and/or control. The mirror’s nonlinear dynamics under such excitation is analyzed in a Hill’s equation form. This form is used to predict stability regions (the voltage-frequency relationship) of parametric resonance behavior over large scanning angles using iterative approximations for nonlinear capacitance behavior of the mirror. Numerical simulations are also performed to obtain the mirror’s frequency response over several voltages for various duty cycles. Frequency sweeps, stability results, and duty cycle trends from both analytical and simulation methods are compared with experimental results. Both analytical models and simulations show good agreement with experimental results over the range of duty cycled excitations tested. This paper discusses the implications of changing amplitude and phase with duty cycle for robust open-loop operation and future closed-loop operating strategies. PMID:25506188

Failed landings after laying hen flight in a commercial aviary over two flock cycles.

PubMed

Campbell, D L M; Goodwin, S L; Makagon, M M; Swanson, J C; Siegford, J M

2016-01-01

Many egg producers are adopting alternative housing systems such as aviaries that provide hens a tiered cage and a litter-covered open floor area. This larger, more complex environment permits expression of behaviors not seen in space-limited cages, such as flight. Flight is an exercise important for strengthening bones; but domestic hens might display imperfect flight landings due to poor flight control. To assess the potential implications of open space, we evaluated the landing success of Lohmann white laying hens in a commercial aviary. Video recordings of hens were taken from 4 aviary sections at peak lay, mid lay and end lay across two flock cycles. Observations were made in each focal section of all flights throughout the day noting flight origin and landing location (outer perch or litter) and landing success or failure. In Flock 1, 9.1% of all flights failed and 21% failed in Flock 2. The number of flights decreased across the laying cycle for both flocks. Proportionally more failed landings were observed in the double row sections in Flock 2. Collisions with other hens were more common than slipping on the ground or colliding with aviary structures across sections and flocks. More hens slipped on the ground and collided with physical structures at peak lay for Flock 2 than at other time points. More collisions with other hens were seen at mid and end lay than at peak lay for Flock 2. Landings ending on perches failed more often than landings on litter. These results indicate potential for flight-related hen injuries in aviary systems resulting from failed landings, which may have implications for hen welfare and optimal system design and management.

Terrestrial and marine perspectives on modeling organic matter degradation pathways.

PubMed

Burd, Adrian B; Frey, Serita; Cabre, Anna; Ito, Takamitsu; Levine, Naomi M; Lønborg, Christian; Long, Matthew; Mauritz, Marguerite; Thomas, R Quinn; Stephens, Brandon M; Vanwalleghem, Tom; Zeng, Ning

2016-01-01

Organic matter (OM) plays a major role in both terrestrial and oceanic biogeochemical cycles. The amount of carbon stored in these systems is far greater than that of carbon dioxide (CO2 ) in the atmosphere, and annual fluxes of CO2 from these pools to the atmosphere exceed those from fossil fuel combustion. Understanding the processes that determine the fate of detrital material is important for predicting the effects that climate change will have on feedbacks to the global carbon cycle. However, Earth System Models (ESMs) typically utilize very simple formulations of processes affecting the mineralization and storage of detrital OM. Recent changes in our view of the nature of this material and the factors controlling its transformation have yet to find their way into models. In this review, we highlight the current understanding of the role and cycling of detrital OM in terrestrial and marine systems and examine how this pool of material is represented in ESMs. We include a discussion of the different mineralization pathways available as organic matter moves from soils, through inland waters to coastal systems and ultimately into open ocean environments. We argue that there is strong commonality between aspects of OM transformation in both terrestrial and marine systems and that our respective scientific communities would benefit from closer collaboration. © 2015 John Wiley & Sons Ltd.

Effects of the estrous cycle and ovarian hormones on behavioral indices of anxiety in female rats.

PubMed

Mora, S; Dussaubat, N; Díaz-Véliz, G

1996-10-01

The influence of the estrous cycle and the effects of exogenous administration of estradiol and progesterone on level of anxiety were studied in intact and ovariectomized rats. Intact Sprague-Dawley female rats were classified according to the stages of estrous cycle. Another group of rats was ovariectomized bilaterally and, 14 days after surgery, they received estradiol benzoate (10 micrograms/kg, s.c.) and/or progesterone (25 mg/kg, s.c.) or corn oil (1 ml/kg). The behavioral tests began 3 h after estradiol or 6 h after progesterone and consisted of: (1) exploration of an elevated plus-maze; and (2) retention of a passive avoidance response. Open-arm exploration of the plus-maze varied according to light intensity and the stages of the estrous cycle. There was a slight increase in open-arm exploration by rats in metestrus, under high light intensity. Low light intensity increased the exploration of the open arms by rats in proestrus and estrus, compared to the other phases of the cycle. Retention of the passive avoidance response was inhibited during proestrus and estrus. Progesterone increased open-arm exploration of the plus-maze under high light conditions, whereas estradiol antagonized this effect. Retention of passive avoidance was inhibited after estradiol or progesterone injection. These results suggest that the behavioral indices of anxiety can vary across the estrous cycle, that low light intensities have anxiolytic-like effects, and that the sensitivity to this effect is higher during proestrus and estrus. This could be explained through modulatory effects of ovarian hormones upon behavioral indices of anxiety.

Field-aligned currents in Saturn's northern nightside magnetosphere: Evidence for interhemispheric current flow associated with planetary period oscillations

NASA Astrophysics Data System (ADS)

Hunt, G. J.; Cowley, S. W. H.; Provan, G.; Bunce, E. J.; Alexeev, I. I.; Belenkaya, E. S.; Kalegaev, V. V.; Dougherty, M. K.; Coates, A. J.

2015-09-01

We investigate the magnetic perturbations associated with field-aligned currents observed on 34 Cassini passes over the premidnight northern auroral region during 2008. These are found to be significantly modulated not only by the northern planetary-period oscillation (PPO) system, similar to the southern currents by the southern PPO system found previously, but also by the southern PPO system as well, thus providing the first clear evidence of PPO-related interhemispheric current flow. The principal field-aligned currents of the two PPO systems are found to be co-located in northern ionospheric colatitude, together with the currents of the PPO-independent (subcorotation) system, located between the vicinity of the open-closed field boundary and field lines mapping to ~9 Saturn radius (Rs) in the equatorial plane. All three systems are of comparable magnitude, ~3 MA in each PPO half-cycle. Smaller PPO-related field-aligned currents of opposite polarity also flow in the interior region, mapping between ~6 and ~9 Rs in the equatorial plane, carrying a current of ~ ±2 MA per half-cycle, which significantly reduce the oscillation amplitudes in the interior region. Within this interior region the amplitudes of the northern and southern oscillations are found to fall continuously with distance along the field lines from the corresponding hemisphere, thus showing the presence of cross-field currents, with the southern oscillations being dominant in the south, and modestly lower in amplitude than the northern oscillations in the north. As in previous studies, no oscillations related to the opposite hemisphere are found on open field lines in either hemisphere.

Comparison of algae cultivation methods for bioenergy production using a combined life cycle assessment and life cycle costing approach.

PubMed

Resurreccion, Eleazer P; Colosi, Lisa M; White, Mark A; Clarens, Andres F

2012-12-01

Algae are an attractive energy source, but important questions still exist about the sustainability of this technology on a large scale. Two particularly important questions concern the method of cultivation and the type of algae to be used. This present study combines elements of life cycle analysis (LCA) and life cycle costing (LCC) to evaluate open pond (OP) systems and horizontal tubular photobioreactors (PBRs) for the cultivation of freshwater (FW) or brackish-to-saline water (BSW) algae. Based on the LCA, OPs have lower energy consumption and greenhouse gas emissions than PBRs; e.g., 32% less energy use for construction and operation. According to the LCC, all four systems are currently financially unattractive investments, though OPs are less so than PBRs. BSW species deliver better energy and GHG performance and higher profitability than FW species in both OPs and PBRs. Sensitivity analyses suggest that improvements in critical cultivation parameters (e.g., CO(2) utilization efficiency or algae lipid content), conversion parameters (e.g., anaerobic digestion efficiency), and market factors (e.g., costs of CO(2) and electricity, or sale prices for algae biodiesel) could alter these results. Copyright © 2012 Elsevier Ltd. All rights reserved.

Respiratory analysis system and method

NASA Technical Reports Server (NTRS)

Liu, F. F. (Inventor)

1973-01-01

A system is described for monitoring the respiratory process in which the gas flow rate and the frequency of respiration and expiration cycles can be determined on a real time basis. A face mask is provided with one-way inlet and outlet valves where the gas flow is through independent flowmeters and through a mass spectrometer. The opening and closing of a valve operates an electrical switch, and the combination of the two switches produces a low frequency electrical signal of the respiratory inhalation and exhalation cycles. During the time a switch is operated, the corresponsing flowmeter produces electric pulses representative of the flow rate; the electrical pulses being at a higher frequency than that of the breathing cycle and combined with the low frequency signal. The high frequency pulses are supplied to conventional analyzer computer which also receives temperature and pressure inputs and computes mass flow rate and totalized mass flow of gas. From the mass spectrometer, components of the gas are separately computed as to flow rate. The electrical switches cause operation of up-down inputs of a reversible counter. The respective up and down cycles can be individually monitored and combined for various respiratory measurements.

A comparison of energy conversion systems for meeting the power requirements of manned rover for Mars missions

NASA Technical Reports Server (NTRS)

El-Genk, Mohamed S.; Morley, Nicholas; Cataldo, Robert; Bloomfield, Harvey

1990-01-01

Several types of conversion systems of interest for a nuclear Mars manned application are examined, including: free-piston Stirling engines (FPSE), He/Xe closed Brayton cycle (CBC), CO2 open Brayton, and SiGe/GaP thermoelectric systems. Optimization studies were conducted to determine the impact of the conversion system on the overall mass of the nuclear power system and the mobility power requirement of the rover vehicle. The results of an analysis of a manned Mars rover equipped with a nuclear reactor power system show that the free-piston Stirling engine and the He/Xe closed Brayton cycle are the best available options for minimizing the overall mass and electric power requirements of the rover vehicle. While the current development of Brayton technology is further advanced than that of FPSE, the FPSE could provide approximately 13.5 percent lower mass than the He/Xe closed Brayton system. Results show that a specific mass of 160 is achievable with FPSE, for which the mass of the radiation shield (2.8 tons) is about half that for He/Xe CBC (5 tons).

A Modern Operating System for Near-real-time Environmental Observatories

NASA Astrophysics Data System (ADS)

Orcutt, John; Vernon, Frank

2014-05-01

The NSF Ocean Observatory Initiative (OOI) provided an opportunity for expanding the capabilities for managing open, near-real-time (latencies of seconds) data from ocean observatories. The sensors deployed in this system largely return data from seafloor, cabled fiber optic cables as well as satellite telemetry. Bandwidth demands range from high-definition movies to the transmission of data via Iridium satellite. The extended Internet also provides an opportunity to not only return data, but to also control the sensors and platforms that comprise the observatory. The data themselves are openly available to any users. In order to provide heightened network security and overall reliability, the connections to and from the sensors/platforms are managed without Layer 3 of the Internet, but instead rely upon message passing using an open protocol termed Advanced Queuing Messaging Protocol (AMQP). The highest bandwidths in the system are in the Regional Scale Network (RSN) off Oregon and Washington and on the continent with highly reliable network connections between observatory components at 10 Gbps. The maintenance of metadata and life cycle histories of sensors and platforms is critical for providing data provenance over the years. The integrated cyberinfrastructure is best thought of as an operating system for the observatory - like the data, the software is also open and can be readily applied to new observatories, for example, in the rapidly evolving Arctic.

Parabolic dish collectors - A solar option

NASA Astrophysics Data System (ADS)

Truscello, V. C.

1981-05-01

A description is given of several parabolic-dish high temperature solar thermal systems currently undergoing performance trials. A single parabolic dish has the potential for generating 20 to 30 kW of electricity with fluid temperatures from 300 to 1650 C. Each dish is a complete power-producing unit, and may function either independently or as part of a group of linked modules. The two dish designs under consideration are of 11 and 12 meter diameters, yielding receiver operating temperatures of 925 and 815 C, respectively. The receiver designs described include (1) an organic working fluid (toluene) Rankine cycle engine; (2) a Brayton open cycle unit incorporating a hybrid combustion chamber and nozzle and a shaft-coupled permanent magnet alternator; and (3) a modified Stirling cycle device originally designed for automotive use. Also considered are thermal buffer energy storage and thermochemical transport and storage.

Identifying Meteorological Controls on Open and Closed Mesoscale Cellular Convection Associated with Marine Cold Air Outbreaks

NASA Astrophysics Data System (ADS)

McCoy, Isabel L.; Wood, Robert; Fletcher, Jennifer K.

2017-11-01

Mesoscale cellular convective (MCC) clouds occur in large-scale patterns over the ocean and have important radiative effects on the climate system. An examination of time-varying meteorological conditions associated with satellite-observed open and closed MCC clouds is conducted to illustrate the influence of large-scale meteorological conditions. Marine cold air outbreaks (MCAO) influence the development of open MCC clouds and the transition from closed to open MCC clouds. MCC neural network classifications on Moderate Resolution Imaging Spectroradiometer (MODIS) data for 2008 are collocated with Clouds and the Earth's Radiant Energy System (CERES) data and ERA-Interim reanalysis to determine the radiative effects of MCC clouds and their thermodynamic environments. Closed MCC clouds are found to have much higher albedo on average than open MCC clouds for the same cloud fraction. Three meteorological control metrics are tested: sea-air temperature difference (ΔT), estimated inversion strength (EIS), and a MCAO index (M). These predictive metrics illustrate the importance of atmospheric surface forcing and static stability for open and closed MCC cloud formation. Predictive sigmoidal relations are found between M and MCC cloud frequency globally and regionally: negative for closed MCC cloud and positive for open MCC cloud. The open MCC cloud seasonal cycle is well correlated with M, while the seasonality of closed MCC clouds is well correlated with M in the midlatitudes and EIS in the tropics and subtropics. M is found to best distinguish open and closed MCC clouds on average over shorter time scales. The possibility of a MCC cloud feedback is discussed.

Effect of water availability in opening containers of breeding site on Aedes aegypti life cycle

NASA Astrophysics Data System (ADS)

Tokachil, Najir; Yusoff, Nuraini; Saaid, Alif; Appandi, Najwa; Harun, Farhana

2017-11-01

The distribution of rainfall is one of the factors which contribute to the development of Aedes aegypti life cycle. The fluctuation of rainfall might influence the acceleration of Aedes aegypti growth by providing sufficient breeding sites. In this research, the availability of water in an opening container of the breeding site is considered as a significant variable which affects the distinct stages structure in mosquito life cycle which egg, larva, pupa, and adult. A stage-structured Lefkovitch matrix model was used by considering the quantity of water contains in an opening container and life cycle of Aedes aegypti. The maximum depth of water in the container was also taken into account in order to find the time duration of mosquito life cycle to complete. We found that the maximum depth of water availability in mosquito breeding site influenced the abundance of the mosquito population. Hence, the containers are filled with sufficient water be able to stand from hot temperature for several days before drying out might continue to provide mosquito breeding site. In the future, it is recommended to consider other factors which affect the quantity of water in mosquito breeding sites such as heavy rain and wind blows.

40 CFR 86.884-7 - Dynamometer operation cycle for smoke emission tests.

Code of Federal Regulations, 2010 CFR

2010-07-01

... 40 Protection of Environment 19 2010-07-01 2010-07-01 false Dynamometer operation cycle for smoke... Dynamometer operation cycle for smoke emission tests. (a) The following sequence of operations shall be... the preconditioning prior to the smoke cycle. (ii) With the throttle remaining in the fully open...

75 FR 51025 - Blue Ribbon Commission on America's Nuclear Future, Reactor and Fuel Cycle Technology Subcommittee

Federal Register 2010, 2011, 2012, 2013, 2014

2010-08-18

... DEPARTMENT OF ENERGY Blue Ribbon Commission on America's Nuclear Future, Reactor and Fuel Cycle... meeting. SUMMARY: This notice announces an open meeting of the Reactor and Fuel Cycle Technology (RFCT... back end of the nuclear fuel cycle. The Commission will provide advice and make recommendations on...

A Cloud-based, Open-Source, Command-and-Control Software Paradigm for Space Situational Awareness (SSA)

NASA Astrophysics Data System (ADS)

Melton, R.; Thomas, J.

With the rapid growth in the number of space actors, there has been a marked increase in the complexity and diversity of software systems utilized to support SSA target tracking, indication, warning, and collision avoidance. Historically, most SSA software has been constructed with "closed" proprietary code, which limits interoperability, inhibits the code transparency that some SSA customers need to develop domain expertise, and prevents the rapid injection of innovative concepts into these systems. Open-source aerospace software, a rapidly emerging, alternative trend in code development, is based on open collaboration, which has the potential to bring greater transparency, interoperability, flexibility, and reduced development costs. Open-source software is easily adaptable, geared to rapidly changing mission needs, and can generally be delivered at lower costs to meet mission requirements. This paper outlines Ball's COSMOS C2 system, a fully open-source, web-enabled, command-and-control software architecture which provides several unique capabilities to move the current legacy SSA software paradigm to an open source model that effectively enables pre- and post-launch asset command and control. Among the unique characteristics of COSMOS is the ease with which it can integrate with diverse hardware. This characteristic enables COSMOS to serve as the command-and-control platform for the full life-cycle development of SSA assets, from board test, to box test, to system integration and test, to on-orbit operations. The use of a modern scripting language, Ruby, also permits automated procedures to provide highly complex decision making for the tasking of SSA assets based on both telemetry data and data received from outside sources. Detailed logging enables quick anomaly detection and resolution. Integrated real-time and offline data graphing renders the visualization of the both ground and on-orbit assets simple and straightforward.

Computational fluid dynamic (CFD) investigation of thermal uniformity in a thermal cycling based calibration chamber for MEMS

NASA Astrophysics Data System (ADS)

Gui, Xulong; Luo, Xiaobing; Wang, Xiaoping; Liu, Sheng

2015-12-01

Micro-electrical-mechanical system (MEMS) has become important for many industries such as automotive, home appliance, portable electronics, especially with the emergence of Internet of Things. Volume testing with temperature compensation has been essential in order to provide MEMS based sensors with repeatability, consistency, reliability, and durability, but low cost. Particularly, in the temperature calibration test, temperature uniformity of thermal cycling based calibration chamber becomes more important for obtaining precision sensors, as each sensor is different before the calibration. When sensor samples are loaded into the chamber, we usually open the door of the chamber, then place fixtures into chamber and mount the samples on the fixtures. These operations may affect temperature uniformity in the chamber. In order to study the influencing factors of sample-loading on the temperature uniformity in the chamber during calibration testing, numerical simulation work was conducted first. Temperature field and flow field were simulated in empty chamber, chamber with open door, chamber with samples, and chamber with fixtures, respectively. By simulation, it was found that opening chamber door, sample size and number of fixture layers all have effects on flow field and temperature field. By experimental validation, it was found that the measured temperature value was consistent with the simulated temperature value.

Engine Cycle Analysis of Air Breathing Microwave Rocket with Reed Valves

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

Fukunari, Masafumi; Komatsu, Reiji; Yamaguchi, Toshikazu

The Microwave Rocket is a candidate for a low cost launcher system. Pulsed plasma generated by a high power millimeter wave beam drives a blast wave, and a vehicle acquires impulsive thrust by exhausting the blast wave. The thrust generation process of the Microwave Rocket is similar to a pulse detonation engine. In order to enhance the performance of its air refreshment, the air-breathing mechanism using reed valves is under development. Ambient air is taken to the thruster through reed valves. Reed valves are closed while the inside pressure is high enough. After the time when the shock wave exhaustsmore » at the open end, an expansion wave is driven and propagates to the thrust-wall. The reed valve is opened by the negative gauge pressure induced by the expansion wave and its reflection wave. In these processes, the pressure oscillation is important parameter. In this paper, the pressure oscillation in the thruster was calculated by CFD combined with the flux through from reed valves, which is estimated analytically. As a result, the air-breathing performance is evaluated using Partial Filling Rate (PFR), the ratio of thruster length to diameter L/D, and ratio of opening area of reed valves to superficial area {alpha}. An engine cycle and predicted thrust was explained.« less

Space environmental effects: Construction and utilization of a system to measure low thermal strain in one meter graphite epoxy tubes

NASA Technical Reports Server (NTRS)

Davis, J. H.; Rives, C.

1982-01-01

A system for measuring the expansion of low coefficient of thermal expansion (CTE) materials was constructed around a H.P. 5526-A laser measuring system. The vacuum CTE measurements in the -150 F to +120 F range were made over a 6 month period on a graphite epoxy tube yielding CTE values of 2.5 to one fifty-millionth/F above ambient and 2 + or - one ten-millionth F below ambient temperature. To assure that the below ambient, approximately 10 microns high open loop nature of the delta L/L vs. T curves was not apparatus related, similar size quartz tubes (A and B) were checked and found to have only a 2 micron (negligable for quartz) open loop component. These two quartz tubes, A and B, had ambient CTE values 20% and 45% respectively higher than the average handbook value. The overnight microcreep diminished an order of magnitude during the first several cycles after the system had been reopened.

Dynamic analysis of gas-core reactor system

NASA Technical Reports Server (NTRS)

Turner, K. H., Jr.

1973-01-01

A heat transfer analysis was incorporated into a previously developed model CODYN to obtain a model of open-cycle gaseous core reactor dynamics which can predict the heat flux at the cavity wall. The resulting model was used to study the sensitivity of the model to the value of the reactivity coefficients and to determine the system response for twenty specified perturbations. In addition, the model was used to study the effectiveness of several control systems in controlling the reactor. It was concluded that control drums located in the moderator region capable of inserting reactivity quickly provided the best control.

Development of a reversible vas deferens occlusive device. VI. Long-term evaluation of flexible prosthetic devices.

PubMed

Brueschke, E E; Zaneveld, L J; Kaleckas, R A; Wingfield, J R

1979-05-01

Fifty-three dogs received implants of several types of flexible devices containing valving mechanisms. These devices were constructed entirely of silicone rubber with the exception of the valve stem, which was made of stainless steel. Generally, the devices were (1) implanted in the open mode and left this way for 27 to 44 months, (2) implanted in the closed mode and kept this way for 11 to 12 months before the valves were reopened, (3) implanted in either the closed or open mode and cycled to the opposite mode every 3 months (four or five cycles), or (4) implanted in either the closed or open mode and cycled to the opposite mode every 6 months (two or three cycles). Different implant methods were also evaluated. Semen analyses were regularly performed on all of the dogs, and a number of the animals were bred during the experiments. It can be concluded that (1) the devices can be opened and closed successfully over long periods, respectively allowing and preventing sperm transport; (2) the breeding ability of the animals is not impaired while the devices are in the open mode, independent of the type of device; (3) the devices do not result in an enhanced incidence of congenital abnormalities in the offspring; and (4) the success rate of device performance does not depend on the method of implanatation used. Thus, the results clearly indicate that the basic mechanism of a soft, reversible valve is a feasible approach to conception control.

Performance comparison of different thermodynamic cycles for an innovative central receiver solar power plant

NASA Astrophysics Data System (ADS)

Reyes-Belmonte, Miguel A.; Sebastián, Andrés; González-Aguilar, José; Romero, Manuel

2017-06-01

The potential of using different thermodynamic cycles coupled to a solar tower central receiver that uses a novel heat transfer fluid is analyzed. The new fluid, named as DPS, is a dense suspension of solid particles aerated through a tubular receiver used to convert concentrated solar energy into thermal power. This novel fluid allows reaching high temperatures at the solar receiver what opens a wide range of possibilities for power cycle selection. This work has been focused into the assessment of power plant performance using conventional, but optimized cycles but also novel thermodynamic concepts. Cases studied are ranging from subcritical steam Rankine cycle; open regenerative Brayton air configurations at medium and high temperature; combined cycle; closed regenerative Brayton helium scheme and closed recompression supercritical carbon dioxide Brayton cycle. Power cycle diagrams and working conditions for design point are compared amongst the studied cases for a common reference thermal power of 57 MWth reaching the central cavity receiver. It has been found that Brayton air cycle working at high temperature or using supercritical carbon dioxide are the most promising solutions in terms of efficiency conversion for the power block of future generation by means of concentrated solar power plants.

A Problem-Solving Environment for Biological Network Informatics: Bio-Spice

DTIC Science & Technology

2007-06-01

user an environment to access software tools. The Dashboard is built upon the NetBeans Integrated Development Environment (IDE), an open source Java...based integration platform was demonstrated. During the subsequent six month development cycle, the first version of the NetBeans based Bio-SPICE...frameworks (OAA, NetBeans , and Systems Biology Workbench (SBW)[15]), it becomes possible for Bio-SPICE tools to truly interoperate. This interoperation

Open Screw Placement in a 1.5 mm LCP Over a Fracture Gap Decreases Fatigue Life

PubMed Central

Alwen, Sarah G. J.; Kapatkin, Amy S.; Garcia, Tanya C.; Milgram, Joshua; Stover, Susan M.

2018-01-01

Objective To investigate the influence of plate and screw hole position on the stability of simulated radial fractures stabilized with a 1.5 mm condylar locking compression plate (LCP). Study Design In vitro mechanical testing of paired cadaveric limbs. Sample Population Paired radii (n = 7) stabilized with a 1.5 mm condylar LCP with an open screw hole positioned either proximal to (PG), or over (OG), a simulated small fracture gap. Methods Constructs were cycled in axial compression at a simulated trot load until failure or a maximum of 200,000 cycles. Specimens that sustained 200,000 cycles without failure were then loaded in axial compression in a single cycle to failure. Construct cyclic axial stiffness and gap strain, fatigue life, and residual strength were evaluated and compared between constructs using analysis of variance. Results Of pairs that had a failure during cyclic loading, OG constructs survived fewer cycles (54,700 ± 60,600) than PG (116,800 ± 49,300). OG constructs had significantly lower initial stiffness throughout cyclic loading and higher gap strain range within the first 1,000 cycles than PG constructs. Residual strength variables were not significantly different between constructs, however yield loads occurred at loads only marginally higher than approximated trot loads. Fatigue life decreased with increasing body weight. Conclusion Fracture fixation stability is compromised by an open screw hole directly over a fracture gap compared to the open screw hole being buttressed by bone in the model studied. The 1.5 mm condylar LCP may be insufficient stabilization in dogs with appropriate radial geometry but high body weights. PMID:29876361

Heat recovery and seed recovery development project: preliminary design report (PDR)

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

Arkett, A. H.; Alexander, K. C.; Bolek, A. D.

1981-06-01

The preliminary design and performance characteristics are described of the 20 MWt heat recovery and seed recovery (HRSR) system to be fabricated, installed, and evaluated to provide a technological basis for the design of commercial size HRSR systems for coal-fired open-cycle MHD power plants. The system description and heat and material balances, equipment description and functional requirements, controls, interfacing systems, and operation and maintenance are detailed. Appendices include: (1) recommended environmental requirements for compliance with federal and state of Tennessee regulations, (2) channel and diffuser simulator, (3) equipment arrangement drawings, and (4) channel and diffuser simulator barrel drawings. (WHK)

Microbial cycling of mercury in contaminated pelagic and wetland sediments of San Pablo Bay, California

USGS Publications Warehouse

Marvin-DiPasquale, M. C.; Agee, J.L.; Bouse, R.M.; Jaffe, B.E.

2003-01-01

San Pablo Bay is an estuary, within northern San Francisco Bay, containing elevated sediment mercury (Hg) levels because of historic loading of hydraulic mining debris during the California gold-rush of the late 1800s. A preliminary investigation of benthic microbial Hg cycling was conducted in surface sediment (0-4 cm) collected from one salt-marsh and three open-water sites. A deeper profile (0-26 cm) was evaluated at one of the open-water locations. Radiolabeled model Hg-compounds were used to measure rates of both methylmercury (MeHg) production and degradation by bacteria. While all sites and depths had similar total-Hg concentrations (0.3-0.6 ppm), and geochemical signatures of mining debris (as eNd, range: -3.08 to -4.37), in-situ MeHg was highest in the marsh (5.4??3.5 ppb) and ??? 0.7 ppb in all open-water sites. Microbial MeHg production (potential rate) in 0-4 surface sediments was also highest in the marsh (3.1 ng g-1 wet sediment day-1) and below detection (<0.06 ng g-1 wet sediment day-1) in open-water locations. The marsh exhibited a methylation/demethylation (M/D) ratio more than 25x that of all open-water locations. Only below the surface 0-4-cm horizon was significant MeHg production potential evident in the open-water sediment profile (0.2-1.1 ng g-1 wet sediment day-1). In-situ Hg methylation rates, calculated from radiotracer rate constants, and in-situ inorganic Hg(II) concentrations compared well with potential rates. However, similarly calculated in-situ rates of MeHg degradation were much lower than potential rates. These preliminary data indicate that wetlands surrounding San Pablo Bay represent important zones of MeHg production, more so than similarly Hg-contaminated adjacent open-water areas. This has significant implications for this and other Hg-impacted systems, where wetland expansion is currently planned.

Reversible switch between the nanoporous and the nonporous state of amphiphilic block copolymer films regulated by selective swelling.

PubMed

Yan, Nina; Wang, Yong

2015-09-21

Switchable nanoporous films, which can repeatedly alternate their porosities, are of great interest in a diversity of fields. Currently these intelligent materials are mostly based on polyelectrolytes and their porosities can change only in relatively narrow ranges, typically under wet conditions, severely limiting their applications. Here we develop a new system, which is capable of reversibly switching between a highly porous state and a nonporous state dozens of times regulated simply by exposure to selective solvents. In this system nanopores are created or reversibly eliminated in films of a block copolymer, polystyrene-block-poly(2-vinyl pyridine) (PS-b-P2VP), by exposing the films to P2VP-selective or PS-selective solvents, respectively. The mechanism of the switch is based on the selective swelling of the constituent blocks in corresponding solvents, which is a nondestructive and easily controllable process enabling the repeatable and ample switch between the open and the closed state. Systematic microscopic and ellipsometric characterization methods are performed to elucidate the pore-closing course induced by nonsolvents and the cycling between the pore-open and the pore-closed state up to 20 times. The affinity of the solvent for PS blocks is found to play a dominating role in determining the pore-closing process and the porosities of the pore-open films increase with the cycling numbers as a result of loose packing conditions of the polymer chains. We finally demonstrate the potential applications of these films as intelligent antireflection coatings and drug carriers.

Model evaluation using a community benchmarking system for land surface models

NASA Astrophysics Data System (ADS)

Mu, M.; Hoffman, F. M.; Lawrence, D. M.; Riley, W. J.; Keppel-Aleks, G.; Kluzek, E. B.; Koven, C. D.; Randerson, J. T.

2014-12-01

Evaluation of atmosphere, ocean, sea ice, and land surface models is an important step in identifying deficiencies in Earth system models and developing improved estimates of future change. For the land surface and carbon cycle, the design of an open-source system has been an important objective of the International Land Model Benchmarking (ILAMB) project. Here we evaluated CMIP5 and CLM models using a benchmarking system that enables users to specify models, data sets, and scoring systems so that results can be tailored to specific model intercomparison projects. Our scoring system used information from four different aspects of global datasets, including climatological mean spatial patterns, seasonal cycle dynamics, interannual variability, and long-term trends. Variable-to-variable comparisons enable investigation of the mechanistic underpinnings of model behavior, and allow for some control of biases in model drivers. Graphics modules allow users to evaluate model performance at local, regional, and global scales. Use of modular structures makes it relatively easy for users to add new variables, diagnostic metrics, benchmarking datasets, or model simulations. Diagnostic results are automatically organized into HTML files, so users can conveniently share results with colleagues. We used this system to evaluate atmospheric carbon dioxide, burned area, global biomass and soil carbon stocks, net ecosystem exchange, gross primary production, ecosystem respiration, terrestrial water storage, evapotranspiration, and surface radiation from CMIP5 historical and ESM historical simulations. We found that the multi-model mean often performed better than many of the individual models for most variables. We plan to publicly release a stable version of the software during fall of 2014 that has land surface, carbon cycle, hydrology, radiation and energy cycle components.

48 CFR 211.274-1 - General.

Code of Federal Regulations, 2012 CFR

2012-10-01

... on leading practices and embraces open standards, DoD can— (a) Achieve lower life-cycle cost of item management and improve life-cycle property management; (b) Improve operational readiness; (c) Provide reliable accountability of property and asset visibility throughout the life cycle; and (d) Reduce the...

48 CFR 211.274-1 - General.

Code of Federal Regulations, 2011 CFR

2011-10-01

... on leading practices and embraces open standards, DoD can— (a) Achieve lower life-cycle cost of item management and improve life-cycle property management; (b) Improve operational readiness; (c) Provide reliable accountability of property and asset visibility throughout the life cycle; and (d) Reduce the...

48 CFR 211.274-1 - General.

Code of Federal Regulations, 2013 CFR

2013-10-01

... on leading practices and embraces open standards, DoD can— (a) Achieve lower life-cycle cost of item management and improve life-cycle property management; (b) Improve operational readiness; (c) Provide reliable accountability of property and asset visibility throughout the life cycle; and (d) Reduce the...

OSI for hardware/software interoperability

NASA Astrophysics Data System (ADS)

Wood, Richard J.; Harvey, Donald L.; Linderman, Richard W.; Gardener, Gary A.; Capraro, Gerard T.

1994-03-01

There is a need in public safety for real-time data collection and transmission from one or more sensors. The Rome Laboratory and the Ballistic Missile Defense Organization are pursuing an effort to bring the benefits of Open System Architectures (OSA) to embedded systems within the Department of Defense. When developed properly OSA provides interoperability, commonality, graceful upgradeability, survivability and hardware/software transportability to greatly minimize life cycle costs, integration and supportability. Architecture flexibility can be achieved to take advantage of commercial accomplishments by basing these developments on vendor-neutral commercially accepted standards and protocols.

Nuclear Thermal Propulsion: A Joint NASA/DOE/DOD Workshop

NASA Technical Reports Server (NTRS)

Clark, John S. (Editor)

1991-01-01

Papers presented at the joint NASA/DOE/DOD workshop on nuclear thermal propulsion are compiled. The following subject areas are covered: nuclear thermal propulsion programs; Rover/NERVA and NERVA systems; Low Pressure Nuclear Thermal Rocket (LPNTR); particle bed reactor nuclear rocket; hybrid propulsion systems; wire core reactor; pellet bed reactor; foil reactor; Droplet Core Nuclear Rocket (DCNR); open cycle gas core nuclear rockets; vapor core propulsion reactors; nuclear light bulb; Nuclear rocket using Indigenous Martian Fuel (NIMF); mission analysis; propulsion and reactor technology; development plans; and safety issues.

Eta Carinae - A Demanding Mistress

NASA Technical Reports Server (NTRS)

Gull, Theodore R.

2011-01-01

Over the past 15 years, a number of observers and modelers have increasingly focused on this massive system that is approaching its end stage, a supernova? a hypernova? When? The discovery by Augusto Damineli that Eta Carinae had a 5.5-year period proved timely as the newly-installed STIS was primed to observe its properties in the visible and ultraviolet. Initial observations occurred on January 1998, and through multiple programs, including the multi-cycle Hubble Treasury program, have sampled changes across two cycles. Now a multi-cycle program, focused on mapping variations in the extended wind-wind collision zones through early 2015, will test 3-D models of the interacting winds. In parallel, studies have been accomplished in X-rays with RXTE and CHANDRA, now in the far infrared with Herschel and from the ground with VLT. Each new observation is helping to peel back the veil of mystery on this massive binary system, but also opening up more questions to be answered. Timely inclusion of laboratory studies and models have greatly enhanced the observational results. We will summarize the latest results including submitted papers and very recent results with Herschel.

Energy and cost savings results for advanced technology systems from the Cogeneration Technology Alternatives Study /CTAS/

NASA Technical Reports Server (NTRS)

Sagerman, G. D.; Barna, G. J.; Burns, R. K.

1979-01-01

The Cogeneration Technology Alternatives Study (CTAS), a program undertaken to identify the most attractive advanced energy conversion systems for industrial cogeneration applications in the 1985-2000 time period, is described, and preliminary results are presented. Two cogeneration options are included in the analysis: a topping application, in which fuel is input to the energy conversion system which generates electricity and waste heat from the conversion system is used to provide heat to the process, and a bottoming application, in which fuel is burned to provide high temperature process heat and waste heat from the process is used as thermal input to the energy conversion system which generates energy. Steam turbines, open and closed cycle gas turbines, combined cycles, diesel engines, Stirling engines, phosphoric acid and molten carbonate fuel cells and thermionics are examined. Expected plant level energy savings, annual energy cost savings, and other results of the economic analysis are given, and the sensitivity of these results to the assumptions concerning fuel prices, price of purchased electricity and the potential effects of regional energy use characteristics is discussed.

Full open-framework batteries for stationary energy storage

NASA Astrophysics Data System (ADS)

Pasta, Mauro; Wessells, Colin D.; Liu, Nian; Nelson, Johanna; McDowell, Matthew T.; Huggins, Robert A.; Toney, Michael F.; Cui, Yi

2014-01-01

New types of energy storage are needed in conjunction with the deployment of renewable energy sources and their integration with the electrical grid. We have recently introduced a family of cathodes involving the reversible insertion of cations into materials with the Prussian Blue open-framework crystal structure. Here we report a newly developed manganese hexacyanomanganate open-framework anode that has the same crystal structure. By combining it with the previously reported copper hexacyanoferrate cathode we demonstrate a safe, fast, inexpensive, long-cycle life aqueous electrolyte battery, which involves the insertion of sodium ions. This high rate, high efficiency cell shows a 96.7% round trip energy efficiency when cycled at a 5C rate and an 84.2% energy efficiency at a 50C rate. There is no measurable capacity loss after 1,000 deep-discharge cycles. Bulk quantities of the electrode materials can be produced by a room temperature chemical synthesis from earth-abundant precursors.

Full open-framework batteries for stationary energy storage.

PubMed

Pasta, Mauro; Wessells, Colin D; Liu, Nian; Nelson, Johanna; McDowell, Matthew T; Huggins, Robert A; Toney, Michael F; Cui, Yi

2014-01-01

New types of energy storage are needed in conjunction with the deployment of renewable energy sources and their integration with the electrical grid. We have recently introduced a family of cathodes involving the reversible insertion of cations into materials with the Prussian Blue open-framework crystal structure. Here we report a newly developed manganese hexacyanomanganate open-framework anode that has the same crystal structure. By combining it with the previously reported copper hexacyanoferrate cathode we demonstrate a safe, fast, inexpensive, long-cycle life aqueous electrolyte battery, which involves the insertion of sodium ions. This high rate, high efficiency cell shows a 96.7% round trip energy efficiency when cycled at a 5C rate and an 84.2% energy efficiency at a 50C rate. There is no measurable capacity loss after 1,000 deep-discharge cycles. Bulk quantities of the electrode materials can be produced by a room temperature chemical synthesis from earth-abundant precursors.

Administrative Preparedness Strategies: Expediting Procurement and Contracting Cycle Times During an Emergency.

PubMed

Hurst, David; Sharpe, Sharon; Yeager, Valerie A

We assessed whether administrative preparedness processes that were intended to expedite the acquisition of goods and services during a public health emergency affect estimated procurement and contracting cycle times. We obtained data from 2014-2015 applications to the Hospital Preparedness Program and Public Health Emergency Preparedness (HPP-PHEP) cooperative agreements. We compared the estimated procurement and contracting cycle times of 61 HPP-PHEP awardees that did and did not have certain administrative processes in place. Certain processes, such as statutes allowing for procuring and contracting on the open market, had an effect on reducing the estimated cycle times for obtaining goods and services. Other processes, such as cooperative purchasing agreements, also had an effect on estimated procurement time. For example, awardees with statutes that permitted them to obtain goods and services in the open market had an average procurement cycle time of 6 days; those without such statutes had a cycle time of 17 days ( P = .04). PHEP awardees should consider adopting these or similar processes in an effort to reduce cycle times.

The Importance of Kinetics and Redox in the Biogeochemical Cycling of Iron in the Surface Ocean

PubMed Central

Croot, Peter L.; Heller, Maija I.

2012-01-01

It is now well established that Iron (Fe) is a limiting element in many regions of the open ocean. Our current understanding of the key processes which control iron distribution in the open ocean have been largely based on thermodynamic measurements performed under the assumption of equilibrium conditions. Using this equilibrium approach, researchers have been able to detect and quantify organic complexing ligands in seawater and examine their role in increasing the overall solubility of iron. Our current knowledge about iron bioavailability to phytoplankton and bacteria is also based heavily on carefully controlled laboratory studies where it is assumed the chemical species are in equilibrium in line with the free ion association model and/or its successor the biotic ligand model. Similarly most field work on iron biogeochemistry generally consists of a single profile which is in essence a “snap-shot” in time of the system under investigation. However it is well known that the surface ocean is an extremely dynamic environment and it is unlikely if thermodynamic equilibrium between all the iron species present is ever truly achieved. In sunlit waters this is mostly due to the daily passage of the sun across the sky leading to photoredox processes which alter Fe speciation by cycling between redox states and between inorganic and organic species. Episodic deposition events, dry and wet, are also important perturbations to iron cycling as they bring in new iron to the system and alter the equilibrium between iron species and phases. Here we utilize new field data collected in the open ocean on the complexation kinetics of iron in the surface ocean to identify the important role of weak iron binding ligands (i.e., those that cannot maintain iron in solution indefinitely at seawater pH: αFeL < αFe′) in allowing transient increases in iron solubility in response to iron deposition events. Experiments with the thermal O2- source SOTS-1 also indicate the short term impact of this species on iron solubility also with relevance to the euphotic zone. This data highlights the roles of kinetics, redox, and weaker iron binding ligands in the biogeochemical cycling of iron in the ocean. PMID:22723797

Vision for an Open, Global Greenhouse Gas Information System (GHGIS)

NASA Astrophysics Data System (ADS)

Duren, R. M.; Butler, J. H.; Rotman, D.; Ciais, P.; Greenhouse Gas Information System Team

2010-12-01

Over the next few years, an increasing number of entities ranging from international, national, and regional governments, to businesses and private land-owners, are likely to become more involved in efforts to limit atmospheric concentrations of greenhouse gases. In such a world, geospatially resolved information about the location, amount, and rate of greenhouse gas (GHG) emissions will be needed, as well as the stocks and flows of all forms of carbon through the earth system. The ability to implement policies that limit GHG concentrations would be enhanced by a global, open, and transparent greenhouse gas information system (GHGIS). An operational and scientifically robust GHGIS would combine ground-based and space-based observations, carbon-cycle modeling, GHG inventories, synthesis analysis, and an extensive data integration and distribution system, to provide information about anthropogenic and natural sources, sinks, and fluxes of greenhouse gases at temporal and spatial scales relevant to decision making. The GHGIS effort was initiated in 2008 as a grassroots inter-agency collaboration intended to identify the needs for such a system, assess the capabilities of current assets, and suggest priorities for future research and development. We will present a vision for an open, global GHGIS including latest analysis of system requirements, critical gaps, and relationship to related efforts at various agencies, the Group on Earth Observations, and the Intergovernmental Panel on Climate Change.

Performance and Environmental Assessment of an Advanced Aircraft with Open Rotor Propulsion

NASA Technical Reports Server (NTRS)

Guynn, Mark D.; Berton, Jeffrey J.; Haller, William J.; Hendricks, Eric S.; Tong, Michael T.

2012-01-01

Application of high speed, advanced turboprops, or "propfans," to transonic transport aircraft received significant attention during the 1970s and 1980s when fuel efficiency was the driving focus of aeronautical research. Unfortunately, after fuel prices declined sharply there was no longer sufficient motivation to continue maturing this technology. Recent volatility in fuel prices and increasing concern for aviation s environmental impact, however, have renewed interest in unducted, open rotor propulsion. Because of the renewed interest in open rotor propulsion, the lack of publicly available up-to-date studies assessing its benefits, and NASA s focus on reducing fuel consumption, a preliminary aircraft system level study on open rotor propulsion was initiated to inform decisions concerning research in this area. New analysis processes were established to assess the characteristics of open rotor aircraft. These processes were then used to assess the performance, noise, and emissions characteristics of an advanced, single-aisle aircraft using open rotor propulsion. The results of this initial study indicate open rotor engines have the potential to provide significant reductions in fuel consumption and landing-takeoff cycle NOX emissions. Noise analysis of the study configuration indicates that an open rotor aircraft in the single-aisle class would be able to meet current noise regulations with margin.

A Universal Organic Cathode for Ultrafast Lithium- and Multivalent Metal Batteries.

PubMed

Fan, Xiulin; Wang, Fei; Ji, Xiao; Wang, Ruixing; Gao, Tao; Hou, Singyuk; Chen, Ji; Deng, Tao; Li, Xiaogang; Chen, Long; Luo, Chao; Wang, Luning; Wang, Chunsheng

2018-04-27

Low-cost multivalent battery chemistries (Mg 2+ , Al 3+ ) have been extensively investigated for large-scale energy storage applications. However, their commercialization is plagued by the poor power density and cycle life of cathodes. A universal polyimides@CNT (PI@CNT) cathode is now presented that can reversibly store various cations with different valences (Li + , Mg 2+ , Al 3+ ) at an extremely fast rate. The ion-coordination charge storage mechanism of PI@CNT is systemically investigated. Full cells using PI@CNT cathodes and corresponding metal anodes exhibit long cycle life (>10000 cycles), fast kinetics (>20 C), and wide operating temperature range (-40 to 50 °C), making the low-cost industrial polyimides universal cathodes for different multivalent metal batteries. The stable ion-coordinated mechanism opens a new foundation for the development of high-energy and high-power multivalent batteries. © 2018 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

High efficiency Brayton cycles using LNG

DOEpatents

Morrow, Charles W [Albuquerque, NM

2006-04-18

A modified, closed-loop Brayton cycle power conversion system that uses liquefied natural gas as the cold heat sink media. When combined with a helium gas cooled nuclear reactor, achievable efficiency can approach 68 76% (as compared to 35% for conventional steam cycle power cooled by air or water). A superheater heat exchanger can be used to exchange heat from a side-stream of hot helium gas split-off from the primary helium coolant loop to post-heat vaporized natural gas exiting from low and high-pressure coolers. The superheater raises the exit temperature of the natural gas to close to room temperature, which makes the gas more attractive to sell on the open market. An additional benefit is significantly reduced costs of a LNG revaporization plant, since the nuclear reactor provides the heat for vaporization instead of burning a portion of the LNG to provide the heat.

A Characteristics-Based Approach to Radioactive Waste Classification in Advanced Nuclear Fuel Cycles

NASA Astrophysics Data System (ADS)

Djokic, Denia

The radioactive waste classification system currently used in the United States primarily relies on a source-based framework. This has lead to numerous issues, such as wastes that are not categorized by their intrinsic risk, or wastes that do not fall under a category within the framework and therefore are without a legal imperative for responsible management. Furthermore, in the possible case that advanced fuel cycles were to be deployed in the United States, the shortcomings of the source-based classification system would be exacerbated: advanced fuel cycles implement processes such as the separation of used nuclear fuel, which introduce new waste streams of varying characteristics. To be able to manage and dispose of these potential new wastes properly, development of a classification system that would assign appropriate level of management to each type of waste based on its physical properties is imperative. This dissertation explores how characteristics from wastes generated from potential future nuclear fuel cycles could be coupled with a characteristics-based classification framework. A static mass flow model developed under the Department of Energy's Fuel Cycle Research & Development program, called the Fuel-cycle Integration and Tradeoffs (FIT) model, was used to calculate the composition of waste streams resulting from different nuclear fuel cycle choices: two modified open fuel cycle cases (recycle in MOX reactor) and two different continuous-recycle fast reactor recycle cases (oxide and metal fuel fast reactors). This analysis focuses on the impact of waste heat load on waste classification practices, although future work could involve coupling waste heat load with metrics of radiotoxicity and longevity. The value of separation of heat-generating fission products and actinides in different fuel cycles and how it could inform long- and short-term disposal management is discussed. It is shown that the benefits of reducing the short-term fission-product heat load of waste destined for geologic disposal are neglected under the current source-based radioactive waste classification system, and that it is useful to classify waste streams based on how favorable the impact of interim storage is on increasing repository capacity. The need for a more diverse set of waste classes is discussed, and it is shown that the characteristics-based IAEA classification guidelines could accommodate wastes created from advanced fuel cycles more comprehensively than the U.S. classification framework.

An Overview of the NASA Fundamental Aeronautics Program Subsonic Fixed Wing Project and Ultra High Bypass Partnership Research Goals

NASA Technical Reports Server (NTRS)

Hughes, Christopher E.

2009-01-01

An overview of the NASA Fundamental Aeronautics Program (FAP) mission and goals is presented. One of the subprograms under the FAP, the Subsonic Fixed Wing Project (SFW), is the focus of the presentation. The SFW system environmental metrics are discussed, along with highlights of planned, systematic approach to research to reduce the environmental impact of commercial aircraft in the areas of acoustics, fuel burn and emissions. The presentation then focuses on collaborative research being conducted with U.S. Industry on the Ultra High Bypass (UHB) engine cycle, the propulsion cycle selected by the SFW to meet the system goals. The partnerships with General Electric Aviation to investigate Open Rotor propulsion concepts and with Pratt & Whitney to investigate the Geared Turbofan UHB engine are highlighted, including current and planned future collaborative research activities with NASA and each organization.

Effect of complete and partial removable dentures on chewing movements.

PubMed

Gonçalves, T M S V; Vilanova, L S R; Gonçalves, L M; Rodrigues Garcia, R C M

2014-03-01

Partial or complete edentulism impairs mastication. However, it is unclear how the chewing cycle is affected by prosthetics. We evaluated the chewing movements of patients fitted with complete (CD) or removable partial denture (RPD). A total of 29 subjects were kinesiographically evaluated during chewing of peanuts and Optocal portions in a random sequence. The subjects were divided into two groups according to prosthesis type. Group RPD was composed of 14 partially edentulous patients using a lower distal extension RPD (mean age 61 ± 8 years), and group CD contained 15 completely edentulous patients using CD (mean age 65·9 ± 7·9 years) in both jaws. Opening, closing, occlusal and masticatory cycle times, movement angle (opening and closing), maximum velocity (opening and closing), total area and chewing cycle amplitudes were evaluated. The results were subjected to anova and Tukey's HSD test at a significance level of 5%. The RPD group exhibited shorter opening and closing phases and masticatory cycle time (P < 0·05). Maximum velocities were also higher in the RPD group, irrespective of the test material (P < 0·05). The area and amplitude of the chewing envelope was smaller in the CD group (P < 0·0001). The test material did not influence chewing cycles in any of the parameters evaluated (P > 0·05). RPD wearers use a faster chewing sequence with greater vertical and lateral jaw excursions compared with CD wearers. © 2013 John Wiley & Sons Ltd.

Conceptual design of the MHD Engineering Test Facility

NASA Technical Reports Server (NTRS)

Bents, D. J.; Bercaw, R. W.; Burkhart, J. A.; Mroz, T. S.; Rigo, H. S.; Pearson, C. V.; Warinner, D. K.; Hatch, A. M.; Borden, M.; Giza, D. A.

1981-01-01

The reference conceptual design of the MHD engineering test facility, a prototype 200 MWe coal-fired electric generating plant designed to demonstrate the commerical feasibility of open cycle MHD is summarized. Main elements of the design are identified and explained, and the rationale behind them is reviewed. Major systems and plant facilities are listed and discussed. Construction cost and schedule estimates are included and the engineering issues that should be reexamined are identified.

Intelligent Computational Systems. Opening Remarks: CFD Application Process Workshop

NASA Technical Reports Server (NTRS)

VanDalsem, William R.

1994-01-01

This discussion will include a short review of the challenges that must be overcome if computational physics technology is to have a larger impact on the design cycles of U.S. aerospace companies. Some of the potential solutions to these challenges may come from the information sciences fields. A few examples of potential computational physics/information sciences synergy will be presented, as motivation and inspiration for the Improving The CFD Applications Process Workshop.

Overview of the Earth System Science Education Alliance Online Courses

NASA Astrophysics Data System (ADS)

Botti, J. A.

2001-12-01

Science education reform has skyrocketed over the last decade in large part thanks to technology-and one technology in particular, the Internet. The World Wide Web has opened up dynamic new online communities of learners. It has allowed educators from around the world to share thoughts about Earth system science and reexamine the way science is taught. A positive offshoot of this reform effort is the Earth System Science Education Alliance (ESSEA). This partnership among universities, colleges, and science education organizations is led by the Institute for Global Environmental Strategies and the Center for Educational TechnologiesTM at Wheeling Jesuit University. ESSEA's mission is to improve Earth system science education. ESSEA has developed three Earth system science courses for K-12 teachers. These online courses guide teachers into collaborative, student-centered science education experiences. Not only do these courses support teachers' professional development, they also help teachers implement Earth systems science content and age-appropriate pedagogical methods into their classrooms. The ESSEA courses are open to elementary, middle school, and high school teachers. Each course lasts one semester. The courses begin with three weeks of introductory content. Then teachers develop content and pedagogical and technological knowledge in four three-week learning cycles. The elementary school course focuses on basic Earth system interactions between land, life, air, and water. In week A of each learning cycle, teachers do earth system activities with their students. In week B teachers investigate aspects of the Earth system -- for instance, the reason rocks change to soil, the relationship between rock weathering and soil nutrients, and the consequent development of biomes. In week C teachers develop classroom activities and share them online with other course participants. The middle school course stresses the effects of real-world events -- volcanic eruptions, hurricanes, rainforest destruction -- on Earth's lithosphere, atmosphere, biosphere, and hydrosphere. Teachers team during week A of each cycle to research the effect of each event on individual spheres. In week B groups "jigsaw" to study the interactions between events, spheres, and positive and negative feedback loops. In week C teachers develop classroom activities. The high school course uses problem-based learning to examine critical areas of global change, such as coral reef degradation, ozone depletion, and climate change. The ESSEA presentation provides examples of learning environments from each of the three courses.

Overview of the Earth System Science Education Alliance Online Courses

NASA Astrophysics Data System (ADS)

Botti, J.; Myers, R.

2002-12-01

Science education reform has skyrocketed over the last decade in large part thanks to technology-and one technology in particular, the Internet. The World Wide Web has opened up dynamic new online communities of learners. It has allowed educators from around the world to share thoughts about Earth system science and reexamine the way science is taught. A positive offshoot of this reform effort is the Earth System Science Education Alliance (ESSEA). This partnership among universities, colleges, and science education organizations is led by the Institute for Global Environmental Strategies and the Center for Educational Technologiestm at Wheeling Jesuit University. ESSEA's mission is to improve Earth system science education. ESSEA has developed three Earth system science courses for K-12 teachers. These online courses guide teachers into collaborative, student-centered science education experiences. Not only do these courses support teachers' professional development, they also help teachers implement Earth systems science content and age-appropriate pedagogical methods into their classrooms. The ESSEA courses are open to elementary, middle school, and high school teachers. Each course lasts one semester. The courses begin with three weeks of introductory content. Then teachers develop content and pedagogical and technological knowledge in four three-week learning cycles. The elementary school course focuses on basic Earth system interactions between land, life, air, and water. In week A of each learning cycle, teachers do earth system activities with their students. In week B teachers investigate aspects of the Earth system-for instance, the reason rocks change to soil, the relationship between rock weathering and soil nutrients, and the consequent development of biomes. In week C teachers develop classroom activities and share them online with other course participants. The middle school course stresses the effects of real-world events-volcanic eruptions, hurricanes, rainforest destruction-on Earth's lithosphere, atmosphere, biosphere, and hydrosphere. Teachers team during week A of each cycle to research the effect of each event on individual spheres. In week B groups "jigsaw" to study the interactions between events, spheres, and positive and negative feedback loops. In week C teachers develop classroom activities. The high school course uses problem-based learning to examine critical areas of global change, such as coral reef degradation, ozone depletion, and climate change. The ESSEA presentation provides examples of learning environments from each of the three courses.

Effects of Repeated Screw Tightening on Implant Abutment Interfaces in Terms of Bacterial and Yeast Leakage in Vitro: One-Time Abutment Versus the Multiscrewing Technique.

PubMed

Calcaterra, Roberta; Di Girolamo, Michele; Mirisola, Concetta; Baggi, Luigi

2016-01-01

Screw loosening can damage the interfaces of implant components, resulting in susceptibility to contamination of the internal parts by microorganisms. The aim of this study was to investigate the impact of abutment screw retightening on the leakage of two different types of bacteria, Streptococcus sanguinis and Fusobacterium nucleatum, and of the yeast Candida albicans. Two types of implant-abutment systems with tube-in-tube interfaces were tested. Groups A and B each used a different type of system that consisted of 20 different pieces that were assembled according to the manufacturer's torque recommendations; four samples in each group were closed just one time, four samples three times, four samples five times, four samples seven times, and four samples nine times. The implants of groups A and B were contaminated with 0.1 μL of microbial solution just before being assembled for the last time to minimize the possibility of contamination. Results showed a direct correlation between the number of colony-forming units grown in the plates and the closing/opening cycles of the implant-abutment systems. Within the limitations of this study, the results indicate the possibility that repeated closing/opening cycles of the implant-abutment unit may influence bacterial/yeast leakage, most likely as a consequence of decreased precision of the coupling between the abutment and the internal part of the dental implant. These findings suggest that a one-time abutment technique may avoid microbiologic leakage in cases of implant-abutment systems with tube-in-tube interfaces.

Study of the kinematic variables of unilateral and habitual mastication of healthy individuals.

PubMed

Pasinato, Fernanda; Oliveira, Andréia Gussi de; Santos-Couto-Paz, Clarissa C; Zeredo, Jorge Luis Lopes; Bolzan, Geovana de Paula; Macedo, Sergio Bruzadelli; Corrêa, Eliane C R

2017-03-30

To describe and compare the temporal-spatial kinematic variables of mandibular movement during deliberate unilateral and habitual mastication in healthy young-adult individuals. The study sample was composed of eight male healthy volunteers aged 19 to 24 years. The kinematic data were obtained using a motion analysis system - Qualisys Track Manager (QTM) ProReflex MCU. Recordings were performed during deliberate unilateral mastication (UM) and habitual mastication (HM) of firm-consistency gummy candy. The following variables were analyzed: (1) masticatory sequence: duration, number of masticatory cycles, and chewing rate; (2) masticatory cycle: duration, vertical and medial-lateral mandibular range of motion in relation to the skull, and maximum velocity during the opening and closing phases. Data of the variables were compared during UM and HM by the paired t test, and the effect sizes ('d' Cohen) were calculated. Regarding the variables of the masticatory sequence, smaller chewing rate was observed for UM compared with that for HM (1.19±0.21Hz and 1.29±0.16Hz, respectively, p=0.004, d=0.53). Smaller values of maximum velocity during the opening (MU=67.4 mm/s and MH=80.02, p=0.053, d=0.80) and closing (MU=71.77±9.35mm/s and MH=3.51±7mm/s, p=0.014, d=0.79) phases of the masticatory cycle were observed in deliberate unilateral mastication compared with those in habitual mastication. Kinematic variables associated with the sequence and cycle of mastication are influenced by the chewing pattern adopted - deliberate unilateral or habitual.

Recovery of nitrogen stable isotope signatures in the food web of an intermittently open estuary following removal of wastewater loads

NASA Astrophysics Data System (ADS)

Smith, Phoebe E.; Oakes, Joanne M.; Eyre, Bradley D.

2016-12-01

Nitrogen (N) stable isotope values (δ15N) were used to assess the removal of wastewater N from the food web within Tallow Creek, a small intermittently closed/open lake/lagoon (ICOLL) on the east coast of Australia, following the cessation of wastewater inputs in 2005. Current (2013) δ15N values of sediment organic carbon, plants, and animals within Tallow Creek were compared to values obtained before wastewater inputs ceased, and to values within a nearby near-pristine ICOLL (Jerusalem Creek). Most biota had significantly depleted δ15N values compared to conspecifics collected before wastewater inputs ceased (mean reduction of 6.0‰; 38% of impacted enrichment), indicating substantial loss of wastewater N since inputs ceased. However, δ15N values remained enriched compared to the near-pristine ICOLL for some components (mean enrichment of 3.3‰ or 38%), suggesting that some wastewater N remains. The δ15N recovery rate (decrease in δ15N as a percentage of the impacted enrichment) for Tallow Creek biota was slow compared to that of biota in more open systems. This slow recovery rate and the persistence of some wastewater N, even after 8 years without new inputs, reflects differences in hydrology and nitrogen cycling between permanently open and intermittently open estuarine systems and highlights the likely lower resilience of ICOLLs to anthropogenic N inputs.

Carbon-Coated Honeycomb Ni-Mn-Co-O Inverse Opal: A High Capacity Ternary Transition Metal Oxide Anode for Li-ion Batteries

PubMed Central

McNulty, David; Geaney, Hugh; O’Dwyer, Colm

2017-01-01

We present the formation of a carbon-coated honeycomb ternary Ni-Mn-Co-O inverse opal as a conversion mode anode material for Li-ion battery applications. In order to obtain high capacity via conversion mode reactions, a single phase crystalline honeycombed IO structure of Ni-Mn-Co-O material was first formed. This Ni-Mn-Co-O IO converts via reversible redox reactions and Li2O formation to a 3D structured matrix assembly of nanoparticles of three (MnO, CoO and NiO) oxides, that facilitates efficient reactions with Li. A carbon coating maintains the structure without clogging the open-worked IO pore morphology for electrolyte penetration and mass transport of products during cycling. The highly porous IO was compared in a Li-ion half-cell to nanoparticles of the same material and showed significant improvement in specific capacity and capacity retention. Further optimization of the system was investigated by incorporating a vinylene carbonate additive into the electrolyte solution which boosted performance, offering promising high-rate performance and good capacity retention over extended cycling. The analysis confirms the possibility of creating a ternary transition metal oxide material with binder free accessible open-worked structure to allow three conversion mode oxides to efficiently cycle as an anode material for Li-ion battery applications. PMID:28186183

Carbon-Coated Honeycomb Ni-Mn-Co-O Inverse Opal: A High Capacity Ternary Transition Metal Oxide Anode for Li-ion Batteries.

PubMed

McNulty, David; Geaney, Hugh; O'Dwyer, Colm

2017-02-10

We present the formation of a carbon-coated honeycomb ternary Ni-Mn-Co-O inverse opal as a conversion mode anode material for Li-ion battery applications. In order to obtain high capacity via conversion mode reactions, a single phase crystalline honeycombed IO structure of Ni-Mn-Co-O material was first formed. This Ni-Mn-Co-O IO converts via reversible redox reactions and Li 2 O formation to a 3D structured matrix assembly of nanoparticles of three (MnO, CoO and NiO) oxides, that facilitates efficient reactions with Li. A carbon coating maintains the structure without clogging the open-worked IO pore morphology for electrolyte penetration and mass transport of products during cycling. The highly porous IO was compared in a Li-ion half-cell to nanoparticles of the same material and showed significant improvement in specific capacity and capacity retention. Further optimization of the system was investigated by incorporating a vinylene carbonate additive into the electrolyte solution which boosted performance, offering promising high-rate performance and good capacity retention over extended cycling. The analysis confirms the possibility of creating a ternary transition metal oxide material with binder free accessible open-worked structure to allow three conversion mode oxides to efficiently cycle as an anode material for Li-ion battery applications.

EDLAMP User’s Manual.

DTIC Science & Technology

1979-07-01

A computer program is described which can be used to analyze plasma chemistry effects on the performance of pulsed, electron-beam sustained, electric discharge lasers operating either in the open cycle or closed cycle mode. (Author)

Vulnerability Management for an Enterprise Resource Planning System

NASA Astrophysics Data System (ADS)

Goel, Shivani; Kiran, Ravi; Garg, Deepak

2012-09-01

Enterprise resource planning (ERP) systems are commonly used in technical educational institutions(TEIs). ERP systems should continue providing services to its users irrespective of the level of failure. There could be many types of failures in the ERP systems. There are different types of measures or characteristics that can be defined for ERP systems to handle the levels of failure. Here in this paper, various types of failure levels are identified along with various characteristics which are concerned with those failures. The relation between all these is summarized. The disruptions causing vulnerabilities in TEIs are identified .A vulnerability management cycle has been suggested along with many commercial and open source vulnerability management tools. The paper also highlights the importance of resiliency in ERP systems in TEIs.

Marine boundary layer cloud regimes and POC formation in an LES coupled to a bulk aerosol scheme

NASA Astrophysics Data System (ADS)

Berner, A. H.; Bretherton, C. S.; Wood, R.; Muhlbauer, A.

2013-07-01

A large-eddy simulation (LES) coupled to a new bulk aerosol scheme is used to study long-lived regimes of aerosol-boundary layer cloud-precipitation interaction and the development of pockets of open cells (POCs) in subtropical stratocumulus cloud layers. The aerosol scheme prognoses mass and number concentration of a single log-normal accumulation mode with surface and entrainment sources, evolving subject to processing of activated aerosol and scavenging of dry aerosol by cloud and rain. The LES with the aerosol scheme is applied to a range of steadily-forced simulations idealized from a well-observed POC case. The long-term system evolution is explored with extended two-dimensional simulations of up to 20 days, mostly with diurnally-averaged insolation. One three-dimensional two-day simulation confirms the initial development of the corresponding two-dimensional case. With weak mean subsidence, an initially aerosol-rich mixed layer deepens, the capping stratocumulus cloud slowly thickens and increasingly depletes aerosol via precipitation accretion, then the boundary layer transitions within a few hours into an open-cell regime with scattered precipitating cumuli, in which entrainment is much weaker. The inversion slowly collapses for several days until the cumulus clouds are too shallow to efficiently precipitate. Inversion cloud then reforms and radiatively drives renewed entrainment, allowing the boundary layer to deepen and become more aerosol-rich, until the stratocumulus layer thickens enough to undergo another cycle of open-cell formation. If mean subsidence is stronger, the stratocumulus never thickens enough to initiate drizzle and settles into a steady state. With lower initial aerosol concentrations, this system quickly transitions into open cells, collapses, and redevelops into a different steady state with a shallow, optically thin cloud layer. In these steady states, interstitial scavenging by cloud droplets is the main sink of aerosol number. The system is described in a reduced two-dimensional phase plane with inversion height and boundary-layer average aerosol concentrations as the state variables. Simulations with a full diurnal cycle show similar evolutions, except that open-cell formation is phase-locked into the early morning hours. The same steadily-forced modeling framework is applied to the development and evolution of a POC and the surrounding overcast boundary layer. An initial aerosol perturbation applied to a portion of the model domain leads that portion to transition into open-cell convection, forming a POC. Reduced entrainment in the POC induces a negative feedback between areal fraction covered by the POC and boundary layer depth changes. This stabilizes the system by controlling liquid water path and precipitation sinks of aerosol number in the overcast region, while also preventing boundary-layer collapse within the POC, allowing the POC and overcast to coexist indefinitely in a quasi-steady equilibrium.

Automotive Gas Turbine Power System-Performance Analysis Code

NASA Technical Reports Server (NTRS)

Juhasz, Albert J.

1997-01-01

An open cycle gas turbine numerical modelling code suitable for thermodynamic performance analysis (i.e. thermal efficiency, specific fuel consumption, cycle state points, working fluid flowrates etc.) of automotive and aircraft powerplant applications has been generated at the NASA Lewis Research Center's Power Technology Division. The use this code can be made available to automotive gas turbine preliminary design efforts, either in its present version, or, assuming that resources can be obtained to incorporate empirical models for component weight and packaging volume, in later version that includes the weight-volume estimator feature. The paper contains a brief discussion of the capabilities of the presently operational version of the code, including a listing of input and output parameters and actual sample output listings.

Primary culture of intestinal epithelial cells as a potential model for Toxoplasma gondii enteric cycle studies.

PubMed

Moura, Marcos de Assis; Amendoeira, Maria Regina Reis; Barbosa, Helene Santos

2009-09-01

The primary culture of intestinal epithelial cells from domestic cats is an efficient cellular model to study the enteric cycle of Toxoplasma gondii in a definitive host. The parasite-host cell ratio can be pointed out as a decisive factor that determines the intracellular fate of bradyzoites forms. The development of the syncytial-like forms of T. gondii was observed using the 1:20 bradyzoite-host cell ratio, resulting in similar forms described in in vivo systems. This alternative study potentially opens up the field for investigation into the molecular aspects of this interaction. This can contribute to the development of new strategies for intervention of a main route by which toxoplasmosis spreads.

Analysis of an open cycle gas core nuclear propulsion system using MHD driven vortices for fuel containment

NASA Astrophysics Data System (ADS)

Sedwick, Raymond John

1998-12-01

A novel method for containing gaseous uranium vapor in an open cycle nuclear space propulsion system is developed. In an attempt to increase the operating temperature of the nuclear reactor beyond the melting point of solid fuel rods (thus increasing specific impulse), the fuel is instead suspended as a vapor in the propellant using the pressure forces developed in a confined vortex flow. The introduction of the fuel as uranium hexafluoride is found to be effective in maintaining its vapor phase in the feed passages from the tank, but not in the main vortex. A mechanism by which the resulting condensation of the uranium may be tolerated is identified, and the electro- optical properties of the resulting mixture are investigated. Containment is modeled using a 1D- axisymmetric geometry, and radiative heat transfer is found to restrict the maximum specific impulse of the system to 1500 seconds using pumping pressures of 500 atm. The specific impulse is related to this pressure as pm1/4, allowing only marginal increases in Isp at increased pressure levels. Additional 2D- axisymmetric issues, such as non-uniform current distribution and bypass flows through the boundary layers, are investigated, with possible methods of solution cited. A two-group, two-region reactor analysis is performed, estimating the mass of the reactor to be about 10 metric tonnes, and establishing the thrust to weight ratio achievable by the system at about 50. To reduce the mass of the power system, a scheme for using cross-flow heat exchange with the propellant flow to minimize (and possibly eliminate) the need for radiators to reject waste heat is presented. (Copies available exclusively from MIT Libraries, Rm. 14-0551, Cambridge, MA 02139-4307. Ph. 617-253-5668; Fax 617-253-1690.)

Simulation Propulsion System and Trajectory Optimization

NASA Technical Reports Server (NTRS)

Hendricks, Eric S.; Falck, Robert D.; Gray, Justin S.

2017-01-01

A number of new aircraft concepts have recently been proposed which tightly couple the propulsion system design and operation with the overall vehicle design and performance characteristics. These concepts include propulsion technology such as boundary layer ingestion, hybrid electric propulsion systems, distributed propulsion systems and variable cycle engines. Initial studies examining these concepts have typically used a traditional decoupled approach to aircraft design where the aerodynamics and propulsion designs are done a-priori and tabular data is used to provide inexpensive look ups to the trajectory ana-ysis. However the cost of generating the tabular data begins to grow exponentially when newer aircraft concepts require consideration of additional operational parameters such as multiple throttle settings, angle-of-attack effects on the propulsion system, or propulsion throttle setting effects on aerodynamics. This paper proposes a new modeling approach that eliminated the need to generate tabular data, instead allowing an expensive propulsion or aerodynamic analysis to be directly integrated into the trajectory analysis model and the entire design problem optimized in a fully coupled manner. The new method is demonstrated by implementing a canonical optimal control problem, the F-4 minimum time-to-climb trajectory optimization using three relatively new analysis tools: Open M-DAO, PyCycle and Pointer. Pycycle and Pointer both provide analytic derivatives and Open MDAO enables the two tools to be combined into a coupled model that can be run in an efficient parallel manner that helps to cost the increased cost of the more expensive propulsion analysis. Results generated with this model serve as a validation of the tightly coupled design method and guide future studies to examine aircraft concepts with more complex operational dependencies for the aerodynamic and propulsion models.

Towards a rechargeable alcohol biobattery

NASA Astrophysics Data System (ADS)

Addo, Paul K.; Arechederra, Robert L.; Minteer, Shelley D.

This research focused on the transition of biofuel cell technology to rechargeable biobatteries. The bioanode compartment of the biobattery consisted of NAD-dependent alcohol dehydrogenase (ADH) immobilized into a carbon composite paste with butyl-3-methylimidazolium chloride (BMIMCl) ionic liquid serving as the electrolyte. Ferrocene was added to shuttle electrons to/from the electrode surface/current collector. The bioanode catalyzed the oxidation of ethanol to acetaldehyde in discharge mode. This bioanode was coupled to a cathode that consisted of Prussian Blue in a carbon composite paste with Nafion 212 acting as the separator between the two compartments. The biobattery can be fabricated in a charged mode with ethanol and have an open circuit potential of 0.8 V in the original state prior to charging or in the discharged mode with acetaldehyde and have an open circuit potential of 0.05 V. After charging it has an open circuit potential of 1.2 V and a maximum power density of 13.0 μW cm -3 and a maximum current density of 35.0 μA cm -3, respectively. The stability and efficiency of the biobattery were studied by cycling continuously at a discharging current of 0.4 mA and the results obtained showed reasonable stability over 50 cycles. This is a new type of secondary battery inspired by the metabolic processes of the living cell, which is an effective energy conversion system.

Students' Understanding of Analogy after a Core (Chemical Observations, Representations, Experimentation) Learning Cycle, General Chemistry Experiment

ERIC Educational Resources Information Center

Avargil, Shirly; Bruce, Mitchell R. M.; Amar, Franc¸ois G.; Bruce, Alice E.

2015-01-01

Students' understanding about analogy was investigated after a CORE learning cycle general chemistry experiment. CORE (Chemical Observations, Representations, Experimentation) is a new three-phase learning cycle that involves (phase 1) guiding students through chemical observations while they consider a series of open-ended questions, (phase 2)…

Development of a Miniature Gas-Bearing Cryogenic Turbo Refrigerator

DTIC Science & Technology

1975-10-01

the rotor balance . AL4TERNATORi lElSIGN Trhe alternatior design is simitlar to previous designs but, because of the required design-point values of...VISOOSITY&MAX CL§*SECofIN**1)093IDOt-0S .JOURNAL DIA* (IN) 00961 ROTOR WEIGHT (LU) 0*0596 LEFT OVERHUNG WT. (LR) 0.0074 WT* 1ETWIEN BRGS. (LB) 0.0396...Open-Cycle Turboalternator Test Station.. a • •. .... 166 77 Open-Cycle Turboalternator Inlet Gas Instrumentation... 167 78 Modified Model MV-6 Balancer

Closed Loop Experiment Manager (CLEM)-An Open and Inexpensive Solution for Multichannel Electrophysiological Recordings and Closed Loop Experiments.

PubMed

Hazan, Hananel; Ziv, Noam E

2017-01-01

There is growing need for multichannel electrophysiological systems that record from and interact with neuronal systems in near real-time. Such systems are needed, for example, for closed loop, multichannel electrophysiological/optogenetic experimentation in vivo and in a variety of other neuronal preparations, or for developing and testing neuro-prosthetic devices, to name a few. Furthermore, there is a need for such systems to be inexpensive, reliable, user friendly, easy to set-up, open and expandable, and possess long life cycles in face of rapidly changing computing environments. Finally, they should provide powerful, yet reasonably easy to implement facilities for developing closed-loop protocols for interacting with neuronal systems. Here, we survey commercial and open source systems that address these needs to varying degrees. We then present our own solution, which we refer to as Closed Loop Experiments Manager (CLEM). CLEM is an open source, soft real-time, Microsoft Windows desktop application that is based on a single generic personal computer (PC) and an inexpensive, general-purpose data acquisition board. CLEM provides a fully functional, user-friendly graphical interface, possesses facilities for recording, presenting and logging electrophysiological data from up to 64 analog channels, and facilities for controlling external devices, such as stimulators, through digital and analog interfaces. Importantly, it includes facilities for running closed-loop protocols written in any programming language that can generate dynamic link libraries (DLLs). We describe the application, its architecture and facilities. We then demonstrate, using networks of cortical neurons growing on multielectrode arrays (MEA) that despite its reliance on generic hardware, its performance is appropriate for flexible, closed-loop experimentation at the neuronal network level.

Closed Loop Experiment Manager (CLEM)—An Open and Inexpensive Solution for Multichannel Electrophysiological Recordings and Closed Loop Experiments

PubMed Central

Hazan, Hananel; Ziv, Noam E.

2017-01-01

There is growing need for multichannel electrophysiological systems that record from and interact with neuronal systems in near real-time. Such systems are needed, for example, for closed loop, multichannel electrophysiological/optogenetic experimentation in vivo and in a variety of other neuronal preparations, or for developing and testing neuro-prosthetic devices, to name a few. Furthermore, there is a need for such systems to be inexpensive, reliable, user friendly, easy to set-up, open and expandable, and possess long life cycles in face of rapidly changing computing environments. Finally, they should provide powerful, yet reasonably easy to implement facilities for developing closed-loop protocols for interacting with neuronal systems. Here, we survey commercial and open source systems that address these needs to varying degrees. We then present our own solution, which we refer to as Closed Loop Experiments Manager (CLEM). CLEM is an open source, soft real-time, Microsoft Windows desktop application that is based on a single generic personal computer (PC) and an inexpensive, general-purpose data acquisition board. CLEM provides a fully functional, user-friendly graphical interface, possesses facilities for recording, presenting and logging electrophysiological data from up to 64 analog channels, and facilities for controlling external devices, such as stimulators, through digital and analog interfaces. Importantly, it includes facilities for running closed-loop protocols written in any programming language that can generate dynamic link libraries (DLLs). We describe the application, its architecture and facilities. We then demonstrate, using networks of cortical neurons growing on multielectrode arrays (MEA) that despite its reliance on generic hardware, its performance is appropriate for flexible, closed-loop experimentation at the neuronal network level. PMID:29093659

Hamiltonian quantum simulation with bounded-strength controls

NASA Astrophysics Data System (ADS)

Bookatz, Adam D.; Wocjan, Pawel; Viola, Lorenza

2014-04-01

We propose dynamical control schemes for Hamiltonian simulation in many-body quantum systems that avoid instantaneous control operations and rely solely on realistic bounded-strength control Hamiltonians. Each simulation protocol consists of periodic repetitions of a basic control block, constructed as a modification of an ‘Eulerian decoupling cycle,’ that would otherwise implement a trivial (zero) target Hamiltonian. For an open quantum system coupled to an uncontrollable environment, our approach may be employed to engineer an effective evolution that simulates a target Hamiltonian on the system while suppressing unwanted decoherence to the leading order, thereby allowing for dynamically corrected simulation. We present illustrative applications to both closed- and open-system simulation settings, with emphasis on simulation of non-local (two-body) Hamiltonians using only local (one-body) controls. In particular, we provide simulation schemes applicable to Heisenberg-coupled spin chains exposed to general linear decoherence, and show how to simulate Kitaev's honeycomb lattice Hamiltonian starting from Ising-coupled qubits, as potentially relevant to the dynamical generation of a topologically protected quantum memory. Additional implications for quantum information processing are discussed.

Effects of Vocal Fold Nodules on Glottal Cycle Measurements Derived from High-Speed Videoendoscopy in Children

PubMed Central

2016-01-01

The goal of this study is to quantify the effects of vocal fold nodules on vibratory motion in children using high-speed videoendoscopy. Differences in vibratory motion were evaluated in 20 children with vocal fold nodules (5–11 years) and 20 age and gender matched typically developing children (5–11 years) during sustained phonation at typical pitch and loudness. Normalized kinematic features of vocal fold displacements from the mid-membranous vocal fold point were extracted from the steady-state high-speed video. A total of 12 kinematic features representing spatial and temporal characteristics of vibratory motion were calculated. Average values and standard deviations (cycle-to-cycle variability) of the following kinematic features were computed: normalized peak displacement, normalized average opening velocity, normalized average closing velocity, normalized peak closing velocity, speed quotient, and open quotient. Group differences between children with and without vocal fold nodules were statistically investigated. While a moderate effect size was observed for the spatial feature of speed quotient, and the temporal feature of normalized average closing velocity in children with nodules compared to vocally normal children, none of the features were statistically significant between the groups after Bonferroni correction. The kinematic analysis of the mid-membranous vocal fold displacement revealed that children with nodules primarily differ from typically developing children in closing phase kinematics of the glottal cycle, whereas the opening phase kinematics are similar. Higher speed quotients and similar opening phase velocities suggest greater relative forces are acting on vocal fold in the closing phase. These findings suggest that future large-scale studies should focus on spatial and temporal features related to the closing phase of the glottal cycle for differentiating the kinematics of children with and without vocal fold nodules. PMID:27124157

Review of Estelle and LOTOS with respect to critical computer applications

NASA Technical Reports Server (NTRS)

Bown, Rodney L.

1991-01-01

Man rated NASA space vehicles seem to represent a set of ultimate critical computer applications. These applications require a high degree of security, integrity, and safety. A variety of formal and/or precise modeling techniques are becoming available for the designer of critical systems. The design phase of the software engineering life cycle includes the modification of non-development components. A review of the Estelle and LOTOS formal description languages is presented. Details of the languages and a set of references are provided. The languages were used to formally describe some of the Open System Interconnect (OSI) protocols.

Air Brayton Solar Receiver, phase 1

NASA Technical Reports Server (NTRS)

Zimmerman, D. K.

1979-01-01

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

Variations of solar, interplanetary, and geomagnetic parameters with solar magnetic multipole fields during Solar Cycles 21-24

NASA Astrophysics Data System (ADS)

Kim, Bogyeong; Lee, Jeongwoo; Yi, Yu; Oh, Suyeon

2015-01-01

In this study we compare the temporal variations of the solar, interplanetary, and geomagnetic (SIG) parameters with that of open solar magnetic flux from 1976 to 2012 (from Solar Cycle 21 to the early phase of Cycle 24) for a purpose of identifying their possible relationships. By the open flux, we mean the average magnetic field over the source surface (2.5 solar radii) times the source area as defined by the potential field source surface (PFSS) model of the Wilcox Solar Observatory (WSO). In our result, most SIG parameters except the solar wind dynamic pressure show rather poor correlations with the open solar magnetic field. Good correlations are recovered when the contributions from individual multipole components are counted separately. As expected, solar activity indices such as sunspot number, total solar irradiance, 10.7 cm radio flux, and solar flare occurrence are highly correlated with the flux of magnetic quadrupole component. The dynamic pressure of solar wind is strongly correlated with the dipole flux, which is in anti-phase with Solar Cycle (SC). The geomagnetic activity represented by the Ap index is correlated with higher order multipole components, which show relatively a slow time variation with SC. We also found that the unusually low geomagnetic activity during SC 23 is accompanied by the weak open solar fields compared with those in other SCs. It is argued that such dependences of the SIG parameters on the individual multipole components of the open solar magnetic flux may clarify why some SIG parameters vary in phase with SC and others show seemingly delayed responses to SC variation.

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

None

An OpenStudio Measure is a script that can manipulate an OpenStudio model and associated data to apply energy conservation measures (ECMs), run supplemental simulations, or visualize simulation results. The OpenStudio software development kit (SDK) and accessibility of the Ruby scripting language makes measure authorship accessible to both software developers and energy modelers. This paper discusses the life cycle of an OpenStudio Measure from development, testing, and distribution, to application.

Inhibition of the ubiquitin-proteasome system by natural products for cancer therapy.

PubMed

Tsukamoto, Sachiko; Yokosawa, Hideyoshi

2010-08-01

The ubiquitin-proteasome system plays a critical role in selective protein degradation and regulates almost all cellular events such as cell cycle progression, signal transduction, cell death, immune responses, metabolism, protein quality control, development, and neuronal function. The recent approval of bortezomib, a synthetic proteasome inhibitor, for the treatment of relapsed multiple myeloma has opened the way to the discovery of drugs targeting the proteasome and ubiquitinating and deubiquitinating enzymes as well as the delivery system. To date, various synthetic and natural products have been reported to inhibit the components of the ubiquitin-proteasome system. Here, we review natural products targeting the ubiquitin-proteasome system as well as synthetic compounds with potent inhibitory effects. Georg Thieme Verlag KG Stuttgart-New York.

Mandibular movement during sleep bruxism associated with current tooth attrition.

PubMed

Okura, Kazuo; Shigemoto, Shuji; Suzuki, Yoshitaka; Noguchi, Naoto; Omoto, Katsuhiro; Abe, Susumu; Matsuka, Yoshizo

2017-01-01

Observation of attrition patterns suggests that mandibular movement in sleep bruxism (SB) may be associated with current tooth attrition. The aim of this study was to confirm this phenomenon by investigating mandibular movement and masseter muscle activity. The subject was a healthy 21-year-old Japanese male. We recorded biological signals including mandibular movement and masseter electromyograms (EMGs) with a polysomnograph. Based on the EMG using Okura's criteria, SB events were classified into clenching, grinding and mixed types according to mandibular movement criteria. The close-open mandibular movement cycles (CO-cycles) during grinding and mixed type events were selected based on mandibular movement trajectories. Fifty-eight CO-cycles were selected in seven grinding and three mixed types. We found that SB mandibular movements associated with current tooth attrition. Excessive lateral movements (ELM) beyond the canine edge-to-edge position were observed in the closing (10.3%) and opening (13.8%) phases of the CO-cycle. Total masseter muscle activity was significantly higher during voluntary grinding (VGR) than during CO-cycle including ELM (working side: P=0.036, balancing side: P=0.025). However, in the middle and late parts of the opening phase, working side masseter muscle activity was significantly higher during CO-cycle including ELM than during VGR (P=0.012). In the early part of the closing phase, balancing side masseter muscle activity was significantly higher during CO-cycle including ELM than during VGR (P=0.017). These findings suggest that excessive forceful grinding during ongoing SB events may have caused canine attrition in this patient. Copyright © 2016 Japan Prosthodontic Society. Published by Elsevier Ltd. All rights reserved.

Opening a New Door

ERIC Educational Resources Information Center

Waters, John K.

2007-01-01

A growing number of K-12 districts are taking the open source plunge, both to cope with tight budgets and to escape proprietary vendor lock-in and expensive upgrade cycles. With the potential for cost savings and a growing number of educational applications, open source software is proving to be an effective alternative for schools willing to make…

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

CHUGH, Devesh; Gluesenkamp, Kyle R; Abdelaziz, Omar

In this study, development of a novel system for combined water heating, dehumidification, and space evaporative cooling is discussed. Ambient water vapor is used as a working fluid in an open system. First, water vapor is absorbed from an air stream into an absorbent solution. The latent heat of absorption is transferred into the process water that cools the absorber. The solution is then regenerated in the desorber, where it is heated by a heating fluid. The water vapor generated in the desorber is condensed and its heat of phase change is transferred to the process water in the condenser.more » The condensed water can then be used in an evaporative cooling process to cool the dehumidified air exiting the absorber, or it can be drained if primarily dehumidification is desired. Essentially, this open absorption cycle collects space heat and transfers it to process water. This technology is enabled by a membrane-based absorption/desorption process in which the absorbent is constrained by hydrophobic vapor-permeable membranes. Constraining the absorbent film has enabled fabrication of the absorber and desorber in a plate-and-frame configuration. An air stream can flow against the membrane at high speed without entraining the absorbent, which is a challenge in conventional dehumidifiers. Furthermore, the absorption and desorption rates of an absorbent constrained by a membrane are greatly enhanced. Isfahani and Moghaddam (Int. J. Heat Mass Transfer, 2013) demonstrated absorption rates of up to 0.008 kg/m2s in a membrane-based absorber and Isfahani et al. (Int. J. Multiphase Flow, 2013) have reported a desorption rate of 0.01 kg/m2s in a membrane-based desorber. The membrane-based architecture also enables economical small-scale systems, novel cycle configurations, and high efficiencies. The absorber, solution heat exchanger, and desorber are fabricated on a single metal sheet. In addition to the open arrangement and membrane-based architecture, another novel feature of the cycle is recovery of the solution heat energy exiting the desorber by process water (a process-solution heat exchanger ) rather than the absorber exiting solution (the conventional solution heat exchanger ). This approach has enabled heating the process water from an inlet temperature of 15 C to 57 C (conforming to the DOE water heater test standard) and interfacing the process water with absorbent on the opposite side of a single metal sheet encompassing the absorber, process-solution heat exchanger, and desorber. The system under development has a 3.2 kW water heating capacity and a target thermal coefficient of performance (COP) of 1.6.« less

A Few Meters Matter: Local Habitats Drive Reproductive Cycles in a Tropical Lizard.

PubMed

Otero, Luisa M; Huey, Raymond B; Gorman, George C

2015-09-01

Reproductive phenology often varies geographically within species, driven by environmental gradients that alter growth and reproduction. However, environments can differ between adjacent habitats at single localities. In lowland Puerto Rico, both open (sunny, warm) and forested (shady, cool) habitats may be only meters apart. The lizard Anolis cristatellus lives in both habitats: it thermoregulates carefully in the open but is a thermoconformer in the forest. To determine whether reproduction differs between habitats, we compared reproductive cycles of females in open versus forest habitats at two localities for over 2 years. Open females were more likely than forest females to be reproductive throughout the year, probably because open females were able to bask and thereby achieve warmer body temperatures. These between-habitat differences in reproduction were especially marked in cool months and are equivalent in magnitude to those between populations separated by elevation. Thus, environmental differences (even on a microlandscape scale) matter to reproduction and probably to demography.

Raphanus sativus, Germination, and Inquiry: A Learning Cycle Approach for Novice Experimenters.

ERIC Educational Resources Information Center

Rillero, Peter

1999-01-01

Describes open-ended experiments with seeds from the common garden radish (Raphanus sativus). The phases of the 5-E learning cycle--Engagement, Exploration, Explanation, Extension, and Evaluation--guide this activity series. (Author/MM)

Life-cycle modification in open oceans accounts for genome variability in a cosmopolitan phytoplankton.

PubMed

von Dassow, Peter; John, Uwe; Ogata, Hiroyuki; Probert, Ian; Bendif, El Mahdi; Kegel, Jessica U; Audic, Stéphane; Wincker, Patrick; Da Silva, Corinne; Claverie, Jean-Michel; Doney, Scott; Glover, David M; Flores, Daniella Mella; Herrera, Yeritza; Lescot, Magali; Garet-Delmas, Marie-José; de Vargas, Colomban

2015-06-01

Emiliania huxleyi is the most abundant calcifying plankton in modern oceans with substantial intraspecific genome variability and a biphasic life cycle involving sexual alternation between calcified 2N and flagellated 1N cells. We show that high genome content variability in Emiliania relates to erosion of 1N-specific genes and loss of the ability to form flagellated cells. Analysis of 185 E. huxleyi strains isolated from world oceans suggests that loss of flagella occurred independently in lineages inhabiting oligotrophic open oceans over short evolutionary timescales. This environmentally linked physiogenomic change suggests life cycling is not advantageous in very large/diluted populations experiencing low biotic pressure and low ecological variability. Gene loss did not appear to reflect pressure for genome streamlining in oligotrophic oceans as previously observed in picoplankton. Life-cycle modifications might be common in plankton and cause major functional variability to be hidden from traditional taxonomic or molecular markers.

A multi-purpose open-source triggering platform for magnetic resonance

NASA Astrophysics Data System (ADS)

Ruytenberg, T.; Webb, A. G.; Beenakker, J. W. M.

2014-10-01

Many MR scans need to be synchronised with external events such as the cardiac or respiratory cycles. For common physiological functions commercial trigger equipment exists, but for more experimental inputs these are not available. This paper describes the design of a multi-purpose open-source trigger platform for MR systems. The heart of the system is an open-source Arduino Due microcontroller. This microcontroller samples an analogue input and digitally processes these data to determine the trigger. The output of the microcontroller is programmed to mimic a physiological signal which is fed into the electrocardiogram (ECG) or pulse oximeter port of MR scanner. The microcontroller is connected to a Bluetooth dongle that allows wireless monitoring and control outside the scanner room. This device can be programmed to generate a trigger based on various types of input. As one example, this paper describes how it can be used as an acoustic cardiac triggering unit. For this, a plastic stethoscope is connected to a microphone which is used as an input for the system. This test setup was used to acquire retrospectively-triggered cardiac scans in ten volunteers. Analysis showed that this platform produces a reliable trigger (>99% triggers are correct) with a small average 8 ms variation between the exact trigger points.

A multi-purpose open-source triggering platform for magnetic resonance.

PubMed

Ruytenberg, T; Webb, A G; Beenakker, J W M

2014-10-01

Many MR scans need to be synchronised with external events such as the cardiac or respiratory cycles. For common physiological functions commercial trigger equipment exists, but for more experimental inputs these are not available. This paper describes the design of a multi-purpose open-source trigger platform for MR systems. The heart of the system is an open-source Arduino Due microcontroller. This microcontroller samples an analogue input and digitally processes these data to determine the trigger. The output of the microcontroller is programmed to mimic a physiological signal which is fed into the electrocardiogram (ECG) or pulse oximeter port of MR scanner. The microcontroller is connected to a Bluetooth dongle that allows wireless monitoring and control outside the scanner room. This device can be programmed to generate a trigger based on various types of input. As one example, this paper describes how it can be used as an acoustic cardiac triggering unit. For this, a plastic stethoscope is connected to a microphone which is used as an input for the system. This test setup was used to acquire retrospectively-triggered cardiac scans in ten volunteers. Analysis showed that this platform produces a reliable trigger (>99% triggers are correct) with a small average 8 ms variation between the exact trigger points. Copyright © 2014 Elsevier Inc. All rights reserved.

Performance of a RBCC Engine in Rocket-Operation

NASA Astrophysics Data System (ADS)

Tomioka, Sadatake; Kubo, Takahiro; Noboru Sakuranaka; Tani, Koichiro

Combination of a scramjet (supersonic combustion ramjet) flow-pass with embedded rocket engines (the combined system termed as Rocket-based Combined Cycle engine) are expected to be the most effective propulsion system for space launch vehicles. Either SSTO (Single Stage To Orbit) system or TSTO (Two Stage To Orbit) system with separation at high altitude needs final stage acceleration in space, so that the RBCC (Rocket Based Combined Cycle) engine should be operated as rocket engines. Performance of the scramjet combustor as the extension to the rocket nozzle, was experimentally evaluated by injecting inert gas at various pressure through the embedded rocket chamber while the whole sub-scaled model was placed in a low pressure chamber connected to an air-driven ejector system. The results showed that the thrust coefficient was about 1.2, the low value being found to mainly due to the friction force on the scramjet combustor wall, while blocking the scramjet flow pass’s opening to increase nozzle extension thrust surface, was found to have little effects on the thrust performance. The combustor was shortened to reduce the friction loss, however, degree of reduction was limited as friction decreased rapidly with distance from the onset of the scramjet combustor.

Membrane-free battery for harvesting low-grade thermal energy.

PubMed

Yang, Yuan; Loomis, James; Ghasemi, Hadi; Lee, Seok Woo; Wang, Yi Jenny; Cui, Yi; Chen, Gang

2014-11-12

Efficient and low-cost systems are desired to harvest the tremendous amount of energy stored in low-grade heat sources (<100 °C). An attractive approach is the thermally regenerative electrochemical cycle (TREC), which uses the dependence of electrode potential on temperature to construct a thermodynamic cycle for direct heat-to-electricity conversion. By varying the temperature, an electrochemical cell is charged at a lower voltage than discharged; thus, thermal energy is converted to electricity. Recently, a Prussian blue analog-based system with high efficiency has been demonstrated. However, the use of an ion-selective membrane in this system raises concerns about the overall cost, which is crucial for waste heat harvesting. Here, we report on a new membrane-free battery with a nickel hexacyanoferrate (NiHCF) cathode and a silver/silver chloride anode. The system has a temperature coefficient of -0.74 mV K(-1). When the battery is discharged at 15 °C and recharged at 55 °C, thermal-to-electricity conversion efficiencies of 2.6% and 3.5% are achieved with assumed heat recuperation of 50% and 70%, respctively. This work opens new opportunities for using membrane-free electrochemical systems to harvest waste heat.

A Comparative Study on the Environmental Impact of CO2 Supermarket Refrigeration Systems

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

Beshr, Mohamed; Aute, Vikrant; Sharma, Vishaldeep

Supermarket refrigeration systems have high environmental impact due to their large refrigerant charge and high leak rates. Accordingly, the interest in using natural refrigerants, such as carbon dioxide (CO2), and new refrigerant blends with low GWP in such systems is increasing. In this paper, an open-source Life Cycle Climate Performance (LCCP) framework is presented and used to compare the environmental impact of three supermarket refrigeration systems. These systems include a transcritical CO2 booster system, a cascade CO2/N-40 system, and a baseline R-404A multiplex direct expansion system. The study is performed for cities representing different climates within the USA using EnergyPlusmore » to simulate the systems' hourly performance. Finally, a parametric analysis is performed to study the impact of annual leak rate on the systems' LCCP.« less

Rapid enrichment of rare-earth metals by carboxymethyl cellulose-based open-cellular hydrogel adsorbent from HIPEs template.

PubMed

Zhu, Yongfeng; Wang, Wenbo; Zheng, Yian; Wang, Feng; Wang, Aiqin

2016-04-20

A series of monolithic open-cellular hydrogel adsorbents based on carboxymethylcellulose (CMC) were prepared through high internal phase emulsions (HIPEs) and used to enrich the rare-earth metals La(3+) and Ce(3+). The changes of pore structure, and the effects of pH, contact time, initial concentration on the adsorption performance were systematically studied. The results show that the as-prepared monolithic hydrogel adsorbents possess good open-cellular framework structure and have fast adsorption kinetics and high adsorption capacity for La(3+) and Ce(3+). The involved adsorption system can reach equilibrium within 30min and the maximal adsorption capacity is determined to be 384.62mg/g for La(3+) and 333.33mg/g for Ce(3+). Moreover, these porous hydrogel adsorbents show an excellent adsorptive reusability for La(3+) and Ce(3+) through five adsorption-desorption cycles. Such a pore hierarchy structure makes this monolithic open-cellular hydrogel adsorbent be an effective adsorbent for effective enrichment of La(3+) and Ce(3+) from aqueous solution. Copyright © 2015 Elsevier Ltd. All rights reserved.

Shelf and open-ocean calcareous phytoplankton assemblages across the Paleocene-Eocene thermal maximum: Implications for global productivity gradients

USGS Publications Warehouse

Gibbs, S.J.; Bralower, T.J.; Bown, Paul R.; Zachos, J.C.; Bybell, L.M.

2006-01-01

Abrupt global warming and profound perturbation of the carbon cycle during the Paleocene-Eocene Thermal Maximum (PETM, ca. 55 Ma) have been linked to a massive release of carbon into the ocean-atmosphere system. Increased phytoplankton productivity has been invoked to cause subsequent CO2 drawdown, cooling, and environmental recovery. However, interpretations of geochemical and biotic data differ on when and where this increased productivity occurred. Here we present high-resolution nannofossil assemblage data from a shelf section (the U.S. Geological Survey [USGS] drill hole at Wilson Lake, New Jersey) and an open-ocean location (Ocean Drilling Program [ODP] Site 1209, paleoequatorial Pacific). These data combined with published biotic records indicate a transient steepening of shelf-offshelf trophic gradients across the PETM onset and peak, with a decrease in open-ocean productivity coeval with increased nutrient availability in shelf areas. Productivity levels recovered in the open ocean during the later stages of the event, which, coupled with intensified continental weathering rates, may have played an important role in carbon sequestration and CO2 drawdown. ?? 2006 Geological Society of America.

The effect of climate variations on the dynamics of pasture–livestock interactions under cooperative and noncooperative management

PubMed Central

Brekke, Kjell Arne; Øksendal, Bernt; Stenseth, Nils Chr.

2007-01-01

It is well known from Hardin's “Tragedy of the Commons” [Hardin G (1968) Science 162:1243–1248] that, if open access is allowed, overgrazing typically results. Hardin, and most authors of the subsequent literature, adopted a static view of the underlying ecosystem. Here we extend this tragedy of the commons to consider the dynamics of the involved ecosystem as well. We consider a general model that allows for a variable carrying capacity of the pastures (due to variation in precipitation) and a stimulating effect on plant growth due to grazing. Our analysis further emphasizes the tragedy; in addition to overgrazing, the ecosystem may approach limit cycles. Thus, unless the pastoralists are able to coordinate themselves, the human capability of long-term planning will generally not stabilize the system. Although numerical optimization shows that a cooperative optimum would yield a high and stable harvest, the open-access system may produce limit cycles, in which even the peak harvest may be below the stable cooperative optimal harvest. Such fluctuations cause both losses in biomass production and utility losses. Our dynamic analysis also demonstrates that, in the absence of cooperation between herders, too much rain in an otherwise dry area might (temporally) destabilize the ecological grazing system through overstocking, subsequently leading to further overgrazing (which will be observed in, but not caused by, the typically dry conditions of landscapes where pastoralism is practiced). In short, through this study we have brought time (and temporal dynamics) into the Hardin's tragedy of the commons and show that the tragedy might be profoundly worsened. PMID:17804790

The effect of climate variations on the dynamics of pasture-livestock interactions under cooperative and noncooperative management.

PubMed

Brekke, Kjell Arne; Øksendal, Bernt; Stenseth, Nils Chr

2007-09-11

It is well known from Hardin's "Tragedy of the Commons" [Hardin G (1968) Science 162:1243-1248] that, if open access is allowed, overgrazing typically results. Hardin, and most authors of the subsequent literature, adopted a static view of the underlying ecosystem. Here we extend this tragedy of the commons to consider the dynamics of the involved ecosystem as well. We consider a general model that allows for a variable carrying capacity of the pastures (due to variation in precipitation) and a stimulating effect on plant growth due to grazing. Our analysis further emphasizes the tragedy; in addition to overgrazing, the ecosystem may approach limit cycles. Thus, unless the pastoralists are able to coordinate themselves, the human capability of long-term planning will generally not stabilize the system. Although numerical optimization shows that a cooperative optimum would yield a high and stable harvest, the open-access system may produce limit cycles, in which even the peak harvest may be below the stable cooperative optimal harvest. Such fluctuations cause both losses in biomass production and utility losses. Our dynamic analysis also demonstrates that, in the absence of cooperation between herders, too much rain in an otherwise dry area might (temporally) destabilize the ecological grazing system through overstocking, subsequently leading to further overgrazing (which will be observed in, but not caused by, the typically dry conditions of landscapes where pastoralism is practiced). In short, through this study we have brought time (and temporal dynamics) into the Hardin's tragedy of the commons and show that the tragedy might be profoundly worsened.

Academic Program Life Cycle: A Redefined Approach to Understanding Market Demands

ERIC Educational Resources Information Center

Mukerji, Siran; Tripathi, Purnendu

2004-01-01

Education can develop intellectual capability in people, which may in turn lead toward development of a more humane society. Open and distance learning (ODL) has provided one means of achieving social objectives democratically. In India significant success has been achieved through a network of 10 open universities and 104 institutes of open and…

Computer program for thermodynamic analysis of open cycle multishaft power system with multiple reheat and intercool

NASA Technical Reports Server (NTRS)

Glassman, A. J.

1974-01-01

A computer program to analyze power systems having any number of shafts up to a maximum of five is presented. On each shaft there can be as many as five compressors and five turbines, along with any specified number of intervening intercoolers and reheaters. A recuperator can be included. Turbine coolant flow can be accounted for. Any fuel consisting entirely of hydrogen and/or carbon can be used. The program is valid for maximum temperatures up to about 2000 K (3600 R). The system description, the analysis method, a detailed explanation of program input and output including an illustrative example, a dictionary of program variables, and the program listing are explained.

High-power UV-LED degradation: Continuous and cycled working condition influence

NASA Astrophysics Data System (ADS)

Arques-Orobon, F. J.; Nuñez, N.; Vazquez, M.; Segura-Antunez, C.; González-Posadas, V.

2015-09-01

High-power (HP) UV-LEDs can replace UV lamps for real-time fluoro-sensing applications by allowing portable and autonomous systems. However, HP UV-LEDs are not a mature technology, and there are still open issues regarding their performance evolution over time. This paper presents a reliability study of 3 W UV-LEDs, with special focus on LED degradation for two working conditions: continuous and cycled (30 s ON and 30 s OFF). Accelerated life tests are developed to evaluate the influence of temperature and electrical working conditions in high-power LEDs degradation, being the predominant failure mechanism the degradation of the package. An analysis that includes dynamic thermal and optical HP UV-LED measurements has been performed. Static thermal and stress simulation analysis with the finite element method (FEM) identifies the causes of package degradation. Accelerated life test results prove that HP UV-LEDs working in cycled condition have a better performance than those working in continuous condition.

Prospects for Accelerator Technology

NASA Astrophysics Data System (ADS)

Todd, Alan

2011-02-01

Accelerator technology today is a greater than US$5 billion per annum business. Development of higher-performance technology with improved reliability that delivers reduced system size and life cycle cost is expected to significantly increase the total accelerator technology market and open up new application sales. Potential future directions are identified and pitfalls in new market penetration are considered. Both of the present big market segments, medical radiation therapy units and semiconductor ion implanters, are approaching the "maturity" phase of their product cycles, where incremental development rather than paradigm shifts is the norm, but they should continue to dominate commercial sales for some time. It is anticipated that large discovery-science accelerators will continue to provide a specialty market beset by the unpredictable cycles resulting from the scale of the projects themselves, coupled with external political and economic drivers. Although fraught with differing market entry difficulties, the security and environmental markets, together with new, as yet unrealized, industrial material processing applications, are expected to provide the bulk of future commercial accelerator technology growth.

Technology development life cycle processes.

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

Beck, David Franklin

2013-05-01

This report and set of appendices are a collection of memoranda originally drafted in 2009 for the purpose of providing motivation and the necessary background material to support the definition and integration of engineering and management processes related to technology development. At the time there was interest and support to move from Capability Maturity Model Integration (CMMI) Level One (ad hoc processes) to Level Three. As presented herein, the material begins with a survey of open literature perspectives on technology development life cycles, including published data on %E2%80%9Cwhat went wrong.%E2%80%9D The main thrust of the material presents a rational expose%CC%81more » of a structured technology development life cycle that uses the scientific method as a framework, with further rigor added from adapting relevant portions of the systems engineering process. The material concludes with a discussion on the use of multiple measures to assess technology maturity, including consideration of the viewpoint of potential users.« less

Large motion high cycle high speed optical fibers for space based applications.

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

Stromberg, Peter G.; Tandon, Rajan; Gibson, Cory S.

2014-10-01

Future remote sensing applications will require higher resolution and therefore higher data rates (up to perhaps 100 gigabits per second) while achieving lower mass and cost. A current limitation to the design space is high speed high bandwidth data does not cross movable gimbals because of cabling issues. This requires the detectors to be off gimbal. The ability to get data across the gimbal would open up efficiencies in designs where the detectors and the electronics can be placed anywhere on the system. Fiber optic cables provide light weight high speed high bandwidth connections. Current options are limited to 20,000more » cycles as opposed to the 1,000,000 cycles needed for future space based applications. To extend this to the million+ regime, requires a thorough understanding of the failure mechanisms and the materials, proper selection of materials (e.g., glass and jacket material) allowable geometry changes to the cable, radiation hardness, etc.« less

Design and Fabrication of a MEMS Flow Sensor and Its Application in Precise Liquid Dispensing

PubMed Central

Liu, Yaxin; Chen, Liguo; Sun, Lining

2009-01-01

A high speed MEMS flow sensor to enhance the reliability and accuracy of a liquid dispensing system is proposed. Benefitting from the sensor information feedback, the system can self-adjust the open time of the solenoid valve to accurately dispense desired volumes of reagent without any pre-calibration. First, an integrated high-speed liquid flow sensor based on the measurement of the pressure difference across a flow channel is presented. Dimensions of the micro-flow channel and two pressure sensors have been appropriately designed to meet the static and dynamic requirements of the liquid dispensing system. Experiments results show that the full scale (FS) flow measurement ranges up to 80 μL/s, with a nonlinearity better than 0.51% FS. Secondly, a novel closed-loop control strategy is proposed to calculate the valve open time in each dispensing cycle, which makes the system immune to liquid viscosity, pressure fluctuation, and other sources of error. Finally, dispensing results show that the system can achieve better dispensing performance, and the coefficient of variance (CV) for liquid dispensing is below 3% at 1 μL and below 4% at 100 nL. PMID:22408517

Design and Fabrication of a MEMS Flow Sensor and Its Application in Precise Liquid Dispensing.

PubMed

Liu, Yaxin; Chen, Liguo; Sun, Lining

2009-01-01

A high speed MEMS flow sensor to enhance the reliability and accuracy of a liquid dispensing system is proposed. Benefitting from the sensor information feedback, the system can self-adjust the open time of the solenoid valve to accurately dispense desired volumes of reagent without any pre-calibration. First, an integrated high-speed liquid flow sensor based on the measurement of the pressure difference across a flow channel is presented. Dimensions of the micro-flow channel and two pressure sensors have been appropriately designed to meet the static and dynamic requirements of the liquid dispensing system. Experiments results show that the full scale (FS) flow measurement ranges up to 80 μL/s, with a nonlinearity better than 0.51% FS. Secondly, a novel closed-loop control strategy is proposed to calculate the valve open time in each dispensing cycle, which makes the system immune to liquid viscosity, pressure fluctuation, and other sources of error. Finally, dispensing results show that the system can achieve better dispensing performance, and the coefficient of variance (CV) for liquid dispensing is below 3% at 1 μL and below 4% at 100 nL.

Human and climate impact on ¹⁵N natural abundance of plants and soils in high-mountain ecosystems: a short review and two examples from the Eastern Pamirs and Mt. Kilimanjaro.

PubMed

Zech, Michael; Bimüller, Carolin; Hemp, Andreas; Samimi, Cyrus; Broesike, Christina; Hörold, Claudia; Zech, Wolfgang

2011-09-01

Population pressure increasingly endangers high-mountain ecosystems such as the pastures in the Eastern Pamirs and the mountain forests on Mt. Kilimanjaro. At the same time, these ecosystems constitute the economic basis for millions of people living there. In our study, we, therefore, aimed at characterising the land-use effects on soil degradation and N-cycling by determining the natural abundance of (15)N. A short review displays that δ(15)N of plant-soil systems may often serve as an integrated indicator of N-cycles with more positive δ(15)N values pointing towards N-losses. Results for the high-mountain pastures in the Eastern Pamirs show that intensively grazed pastures are significantly enriched in (15)N compared to the less-exploited pastures by 3.5 ‰, on average. This can be attributed to soil organic matter degradation, volatile nitrogen losses, nitrogen leaching and a general opening of the N-cycle. Similarly, the intensively degraded savanna soils, the cultivated soils and the soils under disturbed forests on the foothill of Mt. Kilimanjaro reveal very positive δ(15)N values around 6.5 ‰. In contrast, the undisturbed forest soils in the montane zone are more depleted in (15)N, indicating that here the N-cycle is relatively closed. However, significantly higher δ(15)N values characterise the upper montane forest zone at the transition to the subalpine zone. We suggest that this reflects N-losses by the recently monitored and climate change and antropogenically induced increasing fire frequency pushing the upper montane rainforest boundary rapidly downhill. Overall, we conclude that the analysis of the (15)N natural abundance in high-mountain ecosystems is a purposeful tool for detecting land-use- or climate change-induced soil degradation and N-cycle opening.

12 CFR Appendix G to Part 226 - Open-End Model Forms and Clauses

Code of Federal Regulations, 2010 CFR

2010-01-01

... the “adjusted balance” by taking the balance you owed at the end of the previous billing cycle and... cycle. (b) Previous balance method We figure [a portion of] the finance charge on your account by applying the periodic rate to the amount you owe at the beginning of each billing cycle [minus any unpaid...

Interlaminar shear strength and thermo-mechanical properties of nano-enhanced composite materials under thermal shock

NASA Astrophysics Data System (ADS)

Gkikas, G.; Douka, D.-D.; Barkoula, N.-M.; Paipetis, A. S.

2013-04-01

The introduction of nanoscaled reinforcement in otherwise conventional fiber reinforced composite materials has opened an exciting new area in composites research. The unique properties of these materials combined with the design versatility of fibrous composites may offer both enhanced mechanical properties and multiple functionalities which has been a focus area of the aerospace technology on the last decades. Due to unique properties of carbon nanofillers such as huge aspect ratio, extremely large specific surface area as well as high electrical and thermal conductivity, Carbon Nanotubes have benn investigated as multifunvtional materials for electrical, thermal and mechanical applications. In this study, MWCNTs were incorporated in a typical epoxy system using a sonicator. The volume of the nanoreinforcement was 0.5 % by weight. Two different levels of sonication amplitude were used, 50% and 100% respectively. After the sonication, the hardener was introduced in the epoxy, and the system was cured according to the recommended cycle. For comparison purposes, specimens from neat epoxy system were prepared. The thermomechanical properties of the materials manufactured were investigated using a Dynamic Mechanical Analyser. The exposed specimens were subjected to thermal shock. Thermal cycles from +30 °C to -30 °C were carried out and each cycle lasted 24 hours. The thermomechanical properties were studied after 30 cycles . Furthermore, the epoxy systems prepared during the first stage of the study were used for the manufacturing of 16 plies quasi isotropic laminates CFRPs. The modified CFRPs were subjected to thermal shock. For comparison reasons unmodified CFRPs were manufactured and subjected to the same conditions. In addition, the interlaminar shear strength of the specimens was studied using 3-point bending tests before and after the thermal shock. The effect of the nanoreinforcement on the environmental degradation is critically assessed.

Optimal visual simulation of the self-tracking combustion of the infrared decoy based on the particle system

NASA Astrophysics Data System (ADS)

Hu, Qi; Duan, Jin; Wang, LiNing; Zhai, Di

2016-09-01

The high-efficiency simulation test of military weapons has a very important effect on the high cost of the actual combat test and the very demanding operational efficiency. Especially among the simulative emulation methods of the explosive smoke, the simulation method based on the particle system has generated much attention. In order to further improve the traditional simulative emulation degree of the movement process of the infrared decoy during the real combustion cycle, this paper, adopting the virtual simulation platform of OpenGL and Vega Prime and according to their own radiation characteristics and the aerodynamic characteristics of the infrared decoy, has simulated the dynamic fuzzy characteristics of the infrared decoy during the real combustion cycle by using particle system based on the double depth peeling algorithm and has solved key issues such as the interface, coordinate conversion and the retention and recovery of the Vega Prime's status. The simulation experiment has basically reached the expected improvement purpose, effectively improved the simulation fidelity and provided theoretical support for improving the performance of the infrared decoy.

Historical Trends in pH and Carbonate Biogeochemistry on the Belize Mesoamerican Barrier Reef System

NASA Astrophysics Data System (ADS)

Fowell, S. E.; Foster, G. L.; Ries, J. B.; Castillo, K. D.; de la Vega, E.; Tyrrell, T.; Donald, H. K.; Chalk, T. B.

2018-04-01

Coral reefs are important ecosystems that are increasingly negatively impacted by human activities. Understanding which anthropogenic stressors play the most significant role in their decline is vital for the accurate prediction of future trends in coral reef health and for effective mitigation of these threats. Here we present annually resolved boron and carbon isotope measurements of two cores capturing the past 90 years of growth of the tropical reef-building coral Siderastrea siderea from the Belize Mesoamerican Barrier Reef System. The pairing of these two isotope systems allows us to parse the reconstructed pH change into relative changes in net ecosystem productivity and net ecosystem calcification between the two locations. This approach reveals that the relationship between seawater pH and coral calcification, at both a colony and ecosystem level, is complex and cannot simply be modeled as linear or even positive. This study also underscores both the utility of coupled δ11B-δ13C measurements in tracing past biogeochemical cycling in coral reefs and the complexity of this cycling relative to the open ocean.

Quantification of the inevitable: the influence of soil macrofauna on soil water movement in rehabilitated open-cut mine land

NASA Astrophysics Data System (ADS)

Arnold, S.; Williams, E. R.

2015-08-01

Recolonisation of soil by macrofauna (especially ants and termites) in rehabilitated open-cut mine sites is inevitable. In these highly disturbed landscapes, soil invertebrates play a major role in soil development (macropore configuration, nutrient cycling, bioturbation, etc.) and can influence hydrological processes such as infiltration and seepage. Understanding and quantifying these ecosystem processes is important in rehabilitation design, establishment and subsequent management to ensure progress to the desired end-goal, especially in waste cover systems designed to prevent water reaching and transporting underlying hazardous waste materials. However, soil macrofauna are typically overlooked during hydrological modelling, possibly due to uncertainties on the extent of their influence, which can lead to failure of waste cover systems or rehabilitation activities. We propose that scientific experiments under controlled conditions are required to quantify (i) macrofauna - soil structure interactions, (ii) functional dynamics of macrofauna taxa, and (iii) their effects on macrofauna and soil development over time. Such knowledge would provide crucial information for soil water models, which would increase confidence in mine waste cover design recommendations and eventually lead to higher likelihood of rehabilitation success of open-cut mining land.

Improving the Representation of Estuarine Processes in Earth System Models

NASA Astrophysics Data System (ADS)

Sun, Q.; Whitney, M. M.; Bryan, F.; Tseng, Y. H.

2016-12-01

The exchange of freshwater between the rivers and estuaries and the open ocean represents a unique form of scale-interaction in the climate system. The local variability in the terrestrial hydrologic cycle is integrated by rivers over potentially large drainage basins (up to semi-continental scales), and is then imposed on the coastal ocean at the scale of a river mouth. Appropriately treating riverine freshwater discharge into the oceans in Earth system models is a challenging problem. Commonly, the river runoff is discharged into the ocean models with zero salinity and arbitrarily distributed either horizontally or vertically over several grid cells. Those approaches entirely neglect estuarine physical processes that modify river inputs before they reach the open ocean. A physically based Estuary Box Model (EBM) is developed to parameterize the mixing processes in estuaries. The EBM has a two-layer structure representing the mixing processes driven by tides and shear flow within the estuaries. It predicts the magnitude of the mixing driven exchange flow, bringing saltier lower-layer shelf water into the estuary to mix with river water prior to discharge to the upper-layer open ocean. The EBM has been tested against observations and high-resolution three-dimensional simulations of the Columbia River estuary, showing excellent agreement in the predictions of the strength of the exchange flow and the salinity of the discharged water, including modulation with the spring-neap tidal cycle. The EBM is implemented globally at every river discharge point of the Community Earth System Model (CESM). In coupled ocean-sea ice experiments driven by CORE surface forcing, the sea surface salinity (SSS) in the coastal ocean is increased globally compared to the standard model, contributing to a decrease in coastal stratification. The SSS near the mouths of some of the largest rivers is decreased due to the reduction in the area over which riverine fresh water is discharged. The results from experiments with the fully coupled CESM are broadly consistent, supporting the inclusion of the parameterization in CESM version 2 to be released in late 2016.

Thermal electron-tunneling devices as coolers and amplifiers

NASA Astrophysics Data System (ADS)

Su, Shanhe; Zhang, Yanchao; Chen, Jincan; Shih, Tien-Mo

2016-02-01

Nanoscale thermal systems that are associated with a pair of electron reservoirs have been previously studied. In particular, devices that adjust electron tunnels relatively to reservoirs’ chemical potentials enjoy the novelty and the potential. Since only two reservoirs and one tunnel exist, however, designers need external aids to complete a cycle, rendering their models non-spontaneous. Here we design thermal conversion devices that are operated among three electron reservoirs connected by energy-filtering tunnels and also referred to as thermal electron-tunneling devices. They are driven by one of electron reservoirs rather than the external power input, and are equivalent to those coupling systems consisting of forward and reverse Carnot cycles with energy selective electron functions. These previously-unreported electronic devices can be used as coolers and thermal amplifiers and may be called as thermal transistors. The electron and energy fluxes of devices are capable of being manipulated in the same or oppsite directions at our disposal. The proposed model can open a new field in the application of nano-devices.

Thermal electron-tunneling devices as coolers and amplifiers

PubMed Central

Su, Shanhe; Zhang, Yanchao; Chen, Jincan; Shih, Tien-Mo

2016-01-01

Nanoscale thermal systems that are associated with a pair of electron reservoirs have been previously studied. In particular, devices that adjust electron tunnels relatively to reservoirs’ chemical potentials enjoy the novelty and the potential. Since only two reservoirs and one tunnel exist, however, designers need external aids to complete a cycle, rendering their models non-spontaneous. Here we design thermal conversion devices that are operated among three electron reservoirs connected by energy-filtering tunnels and also referred to as thermal electron-tunneling devices. They are driven by one of electron reservoirs rather than the external power input, and are equivalent to those coupling systems consisting of forward and reverse Carnot cycles with energy selective electron functions. These previously-unreported electronic devices can be used as coolers and thermal amplifiers and may be called as thermal transistors. The electron and energy fluxes of devices are capable of being manipulated in the same or oppsite directions at our disposal. The proposed model can open a new field in the application of nano-devices. PMID:26893109

48 CFR 211.274-1 - General.

Code of Federal Regulations, 2010 CFR

2010-10-01

... delivered to DoD that will enhance logistics, contracting, and financial business transactions supporting... on leading practices and embraces open standards, DoD can— (a) Achieve lower life-cycle cost of item management and improve life-cycle property management; (b) Improve operational readiness; (c) Provide...

Integrated Application of Active Controls (IAAC) technology to an advanced subsonic transport project: Test act system validation

NASA Technical Reports Server (NTRS)

1985-01-01

The primary objective of the Test Active Control Technology (ACT) System laboratory tests was to verify and validate the system concept, hardware, and software. The initial lab tests were open loop hardware tests of the Test ACT System as designed and built. During the course of the testing, minor problems were uncovered and corrected. Major software tests were run. The initial software testing was also open loop. These tests examined pitch control laws, wing load alleviation, signal selection/fault detection (SSFD), and output management. The Test ACT System was modified to interface with the direct drive valve (DDV) modules. The initial testing identified problem areas with DDV nonlinearities, valve friction induced limit cycling, DDV control loop instability, and channel command mismatch. The other DDV issue investigated was the ability to detect and isolate failures. Some simple schemes for failure detection were tested but were not completely satisfactory. The Test ACT System architecture continues to appear promising for ACT/FBW applications in systems that must be immune to worst case generic digital faults, and be able to tolerate two sequential nongeneric faults with no reduction in performance. The challenge in such an implementation would be to keep the analog element sufficiently simple to achieve the necessary reliability.

Feedback control of combustion instabilities from within limit cycle oscillations using H∞ loop-shaping and the ν-gap metric

PubMed Central

Morgans, Aimee S.

2016-01-01

Combustion instabilities arise owing to a two-way coupling between acoustic waves and unsteady heat release. Oscillation amplitudes successively grow, until nonlinear effects cause saturation into limit cycle oscillations. Feedback control, in which an actuator modifies some combustor input in response to a sensor measurement, can suppress combustion instabilities. Linear feedback controllers are typically designed, using linear combustor models. However, when activated from within limit cycle, the linear model is invalid, and such controllers are not guaranteed to stabilize. This work develops a feedback control strategy guaranteed to stabilize from within limit cycle oscillations. A low-order model of a simple combustor, exhibiting the essential features of more complex systems, is presented. Linear plane acoustic wave modelling is combined with a weakly nonlinear describing function for the flame. The latter is determined numerically using a level set approach. Its implication is that the open-loop transfer function (OLTF) needed for controller design varies with oscillation level. The difference between the mean and the rest of the OLTFs is characterized using the ν-gap metric, providing the minimum required ‘robustness margin’ for an H∞ loop-shaping controller. Such controllers are designed and achieve stability both for linear fluctuations and from within limit cycle oscillations. PMID:27493558

Impact of Charge Degradation on the Life Cycle Climate Performance of a Residential Air-Conditioning System

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

Beshr, Mohamed; Aute, Vikrant; Abdelaziz, Omar

2014-01-01

Vapor compression systems continuously leak a small fraction of their refrigerant charge to the environment, whether during operation or servicing. As a result of the slow leak rate occurring during operation, the refrigerant charge decreases until the system is serviced and recharged. This charge degradation, after a certain limit, begins to have a detrimental effect on system capacity, energy consumption, and coefficient of performance (COP). This paper presents a literature review and a summary of previous experimental work on the effect of undercharging or charge degradation of different vapor compression systems, especially those without a receiver. These systems include residentialmore » air conditioning and heat pump systems utilizing different components and refrigerants, and water chiller systems. Most of these studies show similar trends for the effect of charge degradation on system performance. However, it is found that although much experimental work exists on the effect of charge degradation on system performance, no correlation or comparison between charge degradation and system performance yet exists. Thus, based on the literature review, three different correlations that characterize the effect of charge on system capacity and energy consumption are developed for different systems as follows: one for air-conditioning systems, one for vapor compression water-to-water chiller systems, and one for heat pumps. These correlations can be implemented in vapor compression cycle simulation tools to obtain a better prediction of the system performance throughout its lifetime. In this paper, these correlations are implemented in an open source tool for life cycle climate performance (LCCP) based design of vapor compression systems. The LCCP of a residential air-source heat pump is evaluated using the tool and the effect of charge degradation on the results is studied. The heat pump is simulated using a validated component-based vapor compression system model and the LCCP results obtained using the three charge degradation correlations are compared.« less

Cyclical period changes in cataclysmic variables: evidence of magnetic activity cycles in the mass-donor star

NASA Astrophysics Data System (ADS)

Borges, B. W.; Baptista, R.

2005-09-01

Cataclymic variables (CVs) are semi-detached binary systems in which a main sequence late-type star (the secondary) fills its Roche lobe and transfers matter to a white dwarf (the primary) through the inner Lagragian point L1. Evolutive models of CVs predicts that the orbital periods Porb of these systems would decrease on time scales of 108 - 109 years due to angular momentum losses either by magnetic braking via the secondary star's wind (Porb > 3 hr) or by emission of gravitational radiation (Porb > 3 hr). These models try to explain the observed gap of systems with Porb in the range of ~ 2 to 3 hr as the consequence of a sharp reduction of magnetic field open lines when the secondary star become fully convective (at Porb ~ 3 hr). However, up to now no well-studied CVs show evidence of period decrease. Instead, most well-observed eclipsing CVs show cyclical period changes probably associated to solar-type (quasi-periodic and/or multiperiodic) magnetic activity cycles in the secondary star. The fast spinning secondaries of CVs, covering a range of masses and rotation periods, are an important laboratory to understand magnetic activities cycles in late type stars. In the present work, we report the investigation of cyclical period changes in IP Peg: CV with orbital periods of 3.8 hr.

Systems-Wide Analysis of Acclimation Responses to Long-Term Heat Stress and Recovery in the Photosynthetic Model Organism Chlamydomonas reinhardtii[W][OPEN

PubMed Central

Hemme, Dorothea; Veyel, Daniel; Mühlhaus, Timo; Sommer, Frederik; Jüppner, Jessica; Unger, Ann-Katrin; Sandmann, Michael; Fehrle, Ines; Schönfelder, Stephanie; Steup, Martin; Geimer, Stefan; Kopka, Joachim; Giavalisco, Patrick; Schroda, Michael

2014-01-01

We applied a top-down systems biology approach to understand how Chlamydomonas reinhardtii acclimates to long-term heat stress (HS) and recovers from it. For this, we shifted cells from 25 to 42°C for 24 h and back to 25°C for ≥8 h and monitored abundances of 1856 proteins/protein groups, 99 polar and 185 lipophilic metabolites, and cytological and photosynthesis parameters. Our data indicate that acclimation of Chlamydomonas to long-term HS consists of a temporally ordered, orchestrated implementation of response elements at various system levels. These comprise (1) cell cycle arrest; (2) catabolism of larger molecules to generate compounds with roles in stress protection; (3) accumulation of molecular chaperones to restore protein homeostasis together with compatible solutes; (4) redirection of photosynthetic energy and reducing power from the Calvin cycle to the de novo synthesis of saturated fatty acids to replace polyunsaturated ones in membrane lipids, which are deposited in lipid bodies; and (5) when sinks for photosynthetic energy and reducing power are depleted, resumption of Calvin cycle activity associated with increased photorespiration, accumulation of reactive oxygen species scavengers, and throttling of linear electron flow by antenna uncoupling. During recovery from HS, cells appear to focus on processes allowing rapid resumption of growth rather than restoring pre-HS conditions. PMID:25415976

A comparison of bleeding patterns and cycle control using two transdermal contraceptive systems: a multicenter, open-label, randomized study.

PubMed

Gruber, D; Skřivánek, A; Serrani, M; Lanius, V; Merz, M

2015-02-01

To investigate the bleeding pattern and cycle control parameters of a contraceptive patch containing 0.55 mg ethinyl estradiol (EE) and 2.1 mg gestodene (GSD) compared with a patch containing 0.6 mg EE and 6 mg norelgestromin (NGMN). In this phase III, open-label, randomized, parallel-group trial, healthy women aged 18-35 years (smokers aged 18-30 years) received either the EE/GSD patch (n=200) or the EE/NGMN patch (n=198). Treatment consisted of one patch per week for 3 weeks followed by a 7-day, patch-free interval for seven cycles. Bleeding control was assessed in two 90-day reference periods. In reference period 1, mean number of bleeding/spotting days was comparable across treatment groups (p>0.05). However, in reference period 2, there were fewer bleeding/spotting days in the EE/GSD patch group (15.7 versus 18.4; p<0.0001). Mean number of bleeding/spotting episodes was comparable across groups for both reference periods, but bleeding/spotting episodes were shorter for the EE/GSD patch than the EE/NGMN patch during reference period 1 (5.13 days versus 5.53 days, respectively; p<0.05) and reference period 2 (5.07 versus 5.66; p=0.0001). Both treatment groups showed a similar frequency of withdrawal bleeding episodes; however, across all seven cycles, the length of these episodes was consistently shorter with the EE/GSD patch (p<0.01). There were no notable treatment differences in intracyclic bleeding. Bleeding pattern and cycle control achieved with the EE/GSD patch was similar to that of the EE/NGMN patch. The paper presents data on the bleeding pattern and cycle control parameters of an investigational transdermal contraceptive patch containing EE and GSD compared with an approved contraceptive patch containing EE and NGMN. This descriptive study found that bleeding patterns associated with the EE/GSD patch were similar to those of an EE/NGMN patch providing higher EE exposure. Copyright © 2015 Elsevier Inc. All rights reserved.

Biomimetic catalytic system driven by electron transfer for selective oxygenation of hydrocarbon.

PubMed

Yang, Guanyu; Ma, Yinfa; Xu, Jie

2004-09-01

Hydrocarbon oxyfunctionalization is a crucial industrial process. Most metallic catalysts require higher temperatures and often show lower selectivities. One of the intellectual approaches is the mimicry for bio-oxidation. We have established a biomimetic system with a nonmetallic redox center, composed of anthraquinones, N-hydroxyphthalimide, and zeolite HY, for selective hydrocarbon oxygenation by molecular oxygen. Selectivity of 95.8% for acetophenone and 66.2% conversion were accomplished for oxygenation of ethylbenzene at temperatures as low as 80 degrees C. The redox cycle, driven by one-electron transfer and product orientation by Zeolite HY, opens up the possibility of mimicking bio-oxidation under mild conditions.

Selection of alternative central-station technologies for the Satellite Power System (SPS) comparative assessment

NASA Technical Reports Server (NTRS)

Samsa, M.

1980-01-01

An important effort is the Satellite Power System (SPS) comparative Assessment is the selection and characterization of alternative technologies to be compared with the SPS concept. The ground rules, criteria, and screening procedure applied in the selection of those alternative technologies are summarized. The final set of central station alternatives selected for comparison with the SPS concept includes: (1) light water reactor with improved fuel utilization, (2) conventional coal combustion with improved environmental controls, (3) open cycle gas turbine with integral low Btu gasifier, (4) terrestrial photovoltaic, (5) liquid metal fast breeder reactor, and (6) magnetic confinement fusion.

Analysis of ProSEDS Test of Bare-Tether Collection

NASA Technical Reports Server (NTRS)

Sanmartin, J. R.; Lorenzini, E. C.; Estes, R. D.; Charro, M.; Cosmo, M. L.

2003-01-01

NASA's tether experiment ProSEDS will be placed in orbit on board a Delta-II rocket to test bare-tether electron collection, deorbiting of the rocket second stage, and the system dynamic stability. ProSEDS performance will vary because ambient conditions change along the orbit and tether-circuit bulk elements at the cathodic end follow the step-by-step sequence for the current cycles of operating modes (open-circuit, shunt and resistor modes for primary cycles; shunt and battery modes for secondary cycles). In this work we discuss expected ProSEDS values of the ratio L,/L*, which jointly with cathodic bulk elements determines bias and current tether profiles; L, is tether length, and L* (changing with tether temperature and ionospheric plasma density and magnetic field) is a characteristic length gauging ohmic versus baretether collection impedances. We discuss how to test bare-tether electron collection during primary cycles, using probe measurements of plasma density, measurements of cathodic current in resistor and shunt modes, and an estimate of tether temperature based on ProSEDS orbital position at the particular cycle concerned. We discuss how a temperature misestimate might occasionally affect the test of bare-tether collection, and how introducing the battery mode in some primary cycles, for an additional current measurement, could obviate the need of a temperature estimate. We also show how to test bare-tether collection by estimating orbit-decay rate from measurements of cathodic current for the shunt and battery modes of secondary cycles.

Systematic Review of Life Cycle Greenhouse Gas Emissions from Geothermal Electricity

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

Eberle, Annika; Heath, Garvin A.; Carpenter Petri, Alberta C.

The primary goal of this work was to assess the magnitude and variability of published life cycle greenhouse gas (GHG) emission estimates for three types of geothermal electricity generation technologies: enhanced geothermal systems (EGS) binary, hydrothermal (HT) flash, and HT binary. These technologies were chosen to align the results of this report with technologies modeled in National Renewable Energy Laboratory's (NREL's) Regional Energy Deployment Systems (ReEDs) model. Although we did gather and screen life cycle assessment (LCA) literature on hybrid systems, dry steam, and two geothermal heating technologies, we did not analyze published GHG emission estimates for these technologies. Inmore » our systematic literature review of the LCA literature, we screened studies in two stages based on a variety of criteria adapted from NREL's Life Cycle Assessment (LCA) Harmonization study (Heath and Mann 2012). Of the more than 180 geothermal studies identified, only 29 successfully passed both screening stages and only 26 of these included estimates of life cycle GHG emissions. We found that the median estimate of life cycle GHG emissions (in grams of carbon dioxide equivalent per kilowatt-hour generated [g CO2eq/kWh]) reported by these studies are 32.0, 47.0, and 11.3 for EGS binary, HT flash, and HT binary, respectively (Figure ES-1). We also found that the total life cycle GHG emissions are dominated by different stages of the life cycle for different technologies. For example, the GHG emissions from HT flash plants are dominated by the operations phase owing to the flash cycle being open loop whereby carbon dioxide entrained in the geothermal fluids is released to the atmosphere. This is in contrast to binary plants (using either EGS or HT resources), whose GHG emissions predominantly originate in the construction phase, owing to its closed-loop process design. Finally, by comparing this review's literature-derived range of HT flash GHG emissions to data from currently operating geothermal plants, we found that emissions from operational plants exhibit more variability and the median of emissions from operational plants is twice the median of operational emissions reported by LCAs. Further investigation is warranted to better understand the cause of differences between published LCAs and estimates from operational plants and to develop LCA analytical approaches that can yield estimates closer to actual emissions.« less

Aeroservoelastic Wind-Tunnel Test of the SUGAR Truss Braced Wing Wind-Tunnel Model

NASA Technical Reports Server (NTRS)

Scott, Robert C.; Allen, Timothy J.; Funk, Christie J.; Castelluccio, Mark A.; Sexton, Bradley W.; Claggett, Scott; Dykman, John; Coulson, David A.; Bartels, Robert E.

2015-01-01

The Subsonic Ultra Green Aircraft Research (SUGAR) Truss-Braced Wing (TBW) aeroservoelastic (ASE) wind-tunnel test was conducted in the NASA Langley Transonic Dynamics Tunnel (TDT) and was completed in April, 2014. The primary goals of the test were to identify the open-loop flutter boundary and then demonstrate flutter suppression. A secondary goal was to demonstrate gust load alleviation (GLA). Open-loop flutter and limit cycle oscillation onset boundaries were identified for a range of Mach numbers and various angles of attack. Two sets of control laws were designed for the model and both sets of control laws were successful in suppressing flutter. Control laws optimized for GLA were not designed; however, the flutter suppression control laws were assessed using the TDT Airstream Oscillation System. This paper describes the experimental apparatus, procedures, and results of the TBW wind-tunnel test. Acquired system ID data used to generate ASE models is also discussed.2 study.

Much Lower Launch Costs Make Resupply Cheaper than Recycling for Space Life Support

NASA Technical Reports Server (NTRS)

Jones, Harry W.

2017-01-01

The development of commercial launch vehicles by SpaceX has greatly reduced the cost of launching mass to Low Earth Orbit (LEO). Reusable launch vehicles may further reduce the launch cost per kilogram. The new low launch cost makes open loop life support much cheaper than before. Open loop systems resupply water and oxygen in tanks for crew use and provide disposable lithium hydroxide (LiOH) in canisters to remove carbon dioxide. Short human space missions such as Apollo and shuttle have used open loop life support, but the long duration International Space Station (ISS) recycles water and oxygen and removes carbon dioxide with a regenerative molecular sieve. These ISS regenerative and recycling life support systems have significantly reduced the total launch mass needed for life support. But, since the development cost of recycling systems is much higher than the cost of tanks and canisters, the relative cost savings have been much less than the launch mass savings. The Life Cycle Cost (LCC) includes development, launch, and operations. If another space station was built in LEO, resupply life support would be much cheaper than the current recycling systems. The mission most favorable to recycling would be a long term lunar base, since the resupply mass would be large, the proximity to Earth would reduce the need for recycling reliability and spares, and the launch cost would be much higher than for LEO due to the need for lunar transit and descent propulsion systems. For a ten-year lunar base, the new low launch costs make resupply cheaper than recycling systems similar to ISS life support.

Towards Simpler Custom and OpenSearch Services for Voluminous NEWS Merged A-Train Data (Invited)

NASA Astrophysics Data System (ADS)

Hua, H.; Fetzer, E.; Braverman, A. J.; Lewis, S.; Henderson, M. L.; Guillaume, A.; Lee, S.; de La Torre Juarez, M.; Dang, H. T.

2010-12-01

To simplify access to large and complex satellite data sets for climate analysis and model verification, we developed web services that is used to study long-term and global-scale trends in climate, water and energy cycle, and weather variability. A related NASA Energy and Water Cycle Study (NEWS) task has created a merged NEWS Level 2 data from multiple instruments in NASA’s A-Train constellation of satellites. We used this data to enable creation of climatologies that include correlation between observed temperature, water vapor and cloud properties from the A-Train sensors. Instead of imposing on the user an often rigid and limiting web-based analysis environment, we recognize the need for simple and well-designed services so that users can perform analysis in their own familiar computing environments. Custom on-demand services were developed to improve data accessibility of voluminous multi-sensor data. Services enabling geospatial, geographical, and multi-sensor parameter subsets of the data, as well a custom time-averaged Level 3 service will be presented. We will also show how a Level 3Q data reduction approach can be used to help “browse” the voluminous multi-sensor Level 2 data. An OpenSearch capability with full text + space + time search of data products will also be presented as an approach to facilitated interoperability with other data systems. We will present our experiences for improving user usability as well as strategies for facilitating interoperability with other data systems.

Mathematical multi-scale model of the cardiovascular system including mitral valve dynamics. Application to ischemic mitral insufficiency

PubMed Central

2011-01-01

Background Valve dysfunction is a common cardiovascular pathology. Despite significant clinical research, there is little formal study of how valve dysfunction affects overall circulatory dynamics. Validated models would offer the ability to better understand these dynamics and thus optimize diagnosis, as well as surgical and other interventions. Methods A cardiovascular and circulatory system (CVS) model has already been validated in silico, and in several animal model studies. It accounts for valve dynamics using Heaviside functions to simulate a physiologically accurate "open on pressure, close on flow" law. However, it does not consider real-time valve opening dynamics and therefore does not fully capture valve dysfunction, particularly where the dysfunction involves partial closure. This research describes an updated version of this previous closed-loop CVS model that includes the progressive opening of the mitral valve, and is defined over the full cardiac cycle. Results Simulations of the cardiovascular system with healthy mitral valve are performed, and, the global hemodynamic behaviour is studied compared with previously validated results. The error between resulting pressure-volume (PV) loops of already validated CVS model and the new CVS model that includes the progressive opening of the mitral valve is assessed and remains within typical measurement error and variability. Simulations of ischemic mitral insufficiency are also performed. Pressure-Volume loops, transmitral flow evolution and mitral valve aperture area evolution follow reported measurements in shape, amplitude and trends. Conclusions The resulting cardiovascular system model including mitral valve dynamics provides a foundation for clinical validation and the study of valvular dysfunction in vivo. The overall models and results could readily be generalised to other cardiac valves. PMID:21942971

Nursing Services Delivery Theory: an open system approach

PubMed Central

Meyer, Raquel M; O’Brien-Pallas, Linda L

2010-01-01

meyer r.m. & o’brien-pallas l.l. (2010)Nursing services delivery theory: an open system approach. Journal of Advanced Nursing66(12), 2828–2838. Aim This paper is a discussion of the derivation of the Nursing Services Delivery Theory from the application of open system theory to large-scale organizations. Background The underlying mechanisms by which staffing indicators influence outcomes remain under-theorized and unmeasured, resulting in a ‘black box’ that masks the nature and organization of nursing work. Theory linking nursing work, staffing, work environments, and outcomes in different settings is urgently needed to inform management decisions about the allocation of nurse staffing resources in organizations. Data sources A search of CINAHL and Business Source Premier for the years 1980–2008 was conducted using the following terms: theory, models, organization, organizational structure, management, administration, nursing units, and nursing. Seminal works were included. Discussion The healthcare organization is conceptualized as an open system characterized by energy transformation, a dynamic steady state, negative entropy, event cycles, negative feedback, differentiation, integration and coordination, and equifinality. The Nursing Services Delivery Theory proposes that input, throughput, and output factors interact dynamically to influence the global work demands placed on nursing work groups at the point of care in production subsystems. Implications for nursing The Nursing Services Delivery Theory can be applied to varied settings, cultures, and countries and supports the study of multi-level phenomena and cross-level effects. Conclusion The Nursing Services Delivery Theory gives a relational structure for reconciling disparate streams of research related to nursing work, staffing, and work environments. The theory can guide future research and the management of nursing services in large-scale healthcare organizations. PMID:20831573

Effect of cycling on the lithium/electrolyte interface in organic electrolytes

NASA Technical Reports Server (NTRS)

Surampudi, S.; Shen, D. H.; Huang, C.-K.; Narayanan, S. R.; Attia, A.; Halpert, G.; Peled, E.

1993-01-01

Nondestructive methods such as ac impedance spectroscopy and microcalorimetry are used to study the effect of cell cycling on the lithium/electrolyte interface. The reactivity of both uncycled and cycled lithium towards various electrolytes is examined by measuring the heat evolved from the cells under open-circuit conditions at 25 C by microcalorimetry. Cycled cells at the end of charge/discharge exhibited considerably higher heat output compared with the uncycled cells. After 30 d of storage, the heat output of the cycled cells is similar to that of the uncycled cells. The cell internal resistance increases with cycling, and this is attributed to the degradation of the electrolyte with cycling.

Intelligent Mining Engineering Systems in the Structure of Industry 4.0

NASA Astrophysics Data System (ADS)

Rylnikova, Marina; Radchenko, Dmitriy; Klebanov, Dmitriy

2017-11-01

The solution of the problem of improving the human environment and working conditions at mines is based on the provision of the rationale of parameters and conditions for the implementation of an environmentally balanced cycle of comprehensive development of mineral deposits on the basis of the design of mining engineering systems characterized by the minimization of the human factor effect in danger zones of mining operations. In this area, robotized technologies are being developed, machinery and mechanisms with the elements of artificial intelligence, and mining and transport system automatic controls are being put into service throughout the world. In the upcoming decades, mining machines and mechanisms will be virtually industrial robots. The article presents the results of zoning of open-pit and underground mine production areas, as well as mining engineering system of combined development depending on the fact and periodicity of human presence in zones of mining processes. As a surface geotechnology case study, the software structure based on a modular concept is described. The performance philosophy of mining and transport equipment with the elements of artificial intelligence is shown when it is put into service in an open pit.

A comparative study on the environmental impact of supermarket refrigeration systems using low GWP refrigerants

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

Beshr, M.; Aute, V.; Sharma, V.

Supermarket refrigeration systems have high environmental impact due to their large refrigerant charge and high leak rates. Consequently, the interest in using low GWP refrigerants such as carbon dioxide (CO 2) and new refrigerant blends is increasing. In this study, an open-source Life Cycle Climate Performance (LCCP) framework is presented and used to compare the environmental impact of four supermarket refrigeration systems: a transcritical CO 2 booster system, a cascade CO 2/N-40 system, a combined secondary circuit with central DX N-40/L-40 system, and a baseline multiplex direct expansion system utilizing R-404A and N-40. The study is performed for different climatesmore » within the USA using EnergyPlus to simulate the systems' hourly performance. Finally, further analyses are presented such as parametric, sensitivity, and uncertainty analyses to study the impact of different system parameters on the LCCP.« less

A comparative study on the environmental impact of supermarket refrigeration systems using low GWP refrigerants

DOE PAGES

Beshr, M.; Aute, V.; Sharma, V.; ...

2015-04-09

Supermarket refrigeration systems have high environmental impact due to their large refrigerant charge and high leak rates. Consequently, the interest in using low GWP refrigerants such as carbon dioxide (CO 2) and new refrigerant blends is increasing. In this study, an open-source Life Cycle Climate Performance (LCCP) framework is presented and used to compare the environmental impact of four supermarket refrigeration systems: a transcritical CO 2 booster system, a cascade CO 2/N-40 system, a combined secondary circuit with central DX N-40/L-40 system, and a baseline multiplex direct expansion system utilizing R-404A and N-40. The study is performed for different climatesmore » within the USA using EnergyPlus to simulate the systems' hourly performance. Finally, further analyses are presented such as parametric, sensitivity, and uncertainty analyses to study the impact of different system parameters on the LCCP.« less

Section 7 reactor incident file general information from 1945

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

Not Available

1969-01-10

At 0308 on January 10, 1966, both B and C Reactors ``scrammed`` due to an electrical fault on Line C2-L8 caused by a raccoon coming in contact with the 13-8 KV line on top of transformer No. 2 at 182-B Building. Line C2-L8 relayed out at the 151-B Building. Details of the occurrence at 151-B are covered in the attachment. C-Reactor scrammed due to reduced voltage on the pressure monitor system. The reduction in voltage caused the auxiliary relays of the pressure monitor ground detector to open, de-energizing the end result relays PSR and PSRA. The safety circuit trip identificationmore » system displayed ``Pressure Monitor`` and ``Ground Detector.`` B-Reactor scrammed by a power failure signal from 190-B Building. The power failure relays for pump numbers 1 and 3 opened due to these pumps contributing power to the fault. The power failure relays at 190-B remained open long enough for the end result relays PF and PFA to open. Since these relays are timed delayed, 0.26 seconds, the power failure relays must have remained open at least that long. At the 190-B Building the steam turbines started due to the power failure relays for pump numbers 1 and 3 opening. The main process pumps remained stable and continued to supply normal flow to the reactor. Pumps were tripped from the line at 182-B and 183-B Buildings. The surge suppressors cycled normally and the turbine export pumps started as a result of low export line pressure. No power equipment was affected in C Area.« less

50 CFR 660.55 - Allocations.

Code of Federal Regulations, 2010 CFR

2010-10-01

... biennial fishing period's open access allocation. (B) [Reserved] (f) Catch accounting. Catch accounting... allocations in a given biennial cycle, catch of those species are counted against the limited entry/open... fisheries—(i) Catch accounting for the trawl allocation. Any groundfish caught by a vessel registered to a...

Pulsed Film Cooling on a Turbine Blade Leading Edge

DTIC Science & Technology

2009-09-01

LEADING EDGE 1. Introduction Gas turbine engines are based on the Brayton cycle in which atmospheric air is compressed, heated via combustion...generation. Because the working fluid is in an open loop, a cooling process is absent from the Brayton cycle. The ideal Brayton cycle (one in which...Technology, Taylor & Francis, 2000. Harrison, K. and Bogard, D., “CFD Predictions of Film Cooling Adiabatic Effectiveness for Cylindrical Holes Embedded

Space Transportation Engine Program (STEP), phase B

NASA Technical Reports Server (NTRS)

1990-01-01

The Space Transportation Engine Program (STEP) Phase 2 effort includes preliminary design and activities plan preparation that will allow smooth and time transition into a Prototype Phase and then into Phases 3, 4, and 5. A Concurrent Engineering approach using Total Quality Management (TQM) techniques, is being applied to define an oxygen-hydrogen engine. The baseline from Phase 1/1' studies was used as a point of departure for trade studies and analyses. Existing STME system models are being enhanced as more detailed module/component characteristics are determined. Preliminary designs for the open expander, closed expander, and gas generator cycles were prepared, and recommendations for cycle selection made at the Design Concept Review (DCR). As a result of July '90 DCR, and information subsequently supplied to the Technical Review Team, a gas generator cycle was selected. Results of the various Advanced Development Programs (ADP's) for the Advanced Launch Systems (ALS) were contributive to this effort. An active vehicle integration effort is supplying the NASA, Air Force, and vehicle contractors with engine parameters and data, and flowing down appropriate vehicle requirements. Engine design and analysis trade studies are being documented in a data base that was developed and is being used to organize information. To date, seventy four trade studies were input to the data base.

Exploration of the aftermath of a large collision in an extreme debris disk

NASA Astrophysics Data System (ADS)

Moor, Attila; Abraham, Peter; Cataldi, Gianni; Kospal, Agnes; Pal, Andras; Vida, Krisztian

2018-05-01

Warm debris disks with extremely high fractional luminosities are exceptional, rare systems. Not explainable by steady-state evolutionary models, these extreme debris disks are believed to stem from a recent large collision of planetary embryos in the terrestrial zone. Our team recently discovered a new extreme debris disk around TYC 4209-1322-1, whose WISE W1/W2 band photometry showed a significant brightening probably related to a giant collision in the inner disk. In Cycle 13 we monitor the system by Spitzer, revealing a fading trend with an e-folding time of 1500 days with hints for a quasi-periodic modulation and a possible second smaller amplitude collision event. Here we propose to continue the monitoring campaign until the end of Cycle 14 to explore the evolution of the current long fading trend and of the second collision, and characterize the hinted modulation. Thanks to a better sampled Spitzer light curve and the unique opportunity that NASA's TESS satellite will obtain high-precision optical photometry in the same period, a new dimension will be opened in Cycle 14 in the study of one of the most spectacular extreme debris disk, scrutinizing for the first time the possible influence of stellar activity on a debris disk.

A life cycle assessment of destruction of ammunition.

PubMed

Alverbro, K; Björklund, A; Finnveden, G; Hochschorner, E; Hägvall, J

2009-10-30

The Swedish Armed Forces have large stocks of ammunition that were produced at a time when decommissioning was not considered. This ammunition will eventually become obsolete and must be destroyed, preferably with minimal impact on the environment and in a safe way for personnel. The aim of this paper is to make a comparison of the environmental impacts in a life cycle perspective of three different methods of decommissioning/destruction of ammunition, and to identify the environmental advantages and disadvantages of each of these destruction methods: open detonation; static kiln incineration with air pollution control combined with metal recycling, and a combination of incineration with air pollution control, open burning, recovery of some energetic material and metal recycling. Data used are for the specific processes and from established LCA databases. Recycling the materials in the ammunition and minimising the spread of airborne pollutants during incineration were found to be the most important factors affecting the life cycle environmental performance of the compared destruction methods. Open detonation with or without metal recycling proved to be the overall worst alternative from a life cycle perspective. The results for the static kiln and combination treatment indicate that the kind of ammunition and location of the destruction plant might determine the choice of method, since the environmental impacts from these methods are of little difference in the case of this specific grenade. Different methods for destruction of ammunition have previously been discussed from a risk and safety perspective. This is however to our knowledge the first study looking specifically on environmentally aspect in a life cycle perspective.

Product environmental footprint of strawberries: Case studies in Estonia and Germany.

PubMed

Soode-Schimonsky, Eveli; Richter, Klaus; Weber-Blaschke, Gabriele

2017-12-01

The environmental impacts of strawberries have been assessed in several studies. However, these studies either present dissimilar results or only focus on single impact categories without offering a comprehensive overview of environmental impacts. We applied the product environmental footprint (PEF) methodology to broadly indicate the environmental impacts of various strawberry production systems in Germany and Estonia by 15 impact categories. Data for the 7 case studies were gathered from two farms with organic and two farms with conventional open field production systems in Estonia and from one farm with conventional open field and one farm with a polytunnel and greenhouse production system in Germany. The greenhouse production system had the highest environmental impact with a PEF of 0.0040. In the field organic production systems, the PEF was 0.0029 and 0.0028. The field conventional production systems resulted in a PEF of 0.0008, 0.0009 and 0.0002. Polytunnel PEF was 0.0006. Human toxicity cancer effects, particulate matter and human toxicity non-cancer effects resulted in the highest impact across all analysed production systems. The main contributors were electricity for cooling, heating the greenhouse and the use of agricultural machinery including fuel burning. While production stage contributed 85% of the total impact in the greenhouse, also other life cycle stages were important contributors: pre-chain resulted in 71% and 90% of impact in conventional and polytunnels, respectively, and cooling was 47% in one organic system. Environmental impact from strawberry cooling can be reduced by more efficient use of the cooling room, increasing the strawberry yield or switching from oil shale electricity to other energy sources. Greenhouse heating is the overall impact hotspot even if it based on renewable resources. A ranking of production systems based on the environmental impact is possible only if all relevant impacts are included. Future studies should aim for detailed results across a variety of impact categories and follow product category rules in defining the life cycle stages. Copyright © 2017 Elsevier Ltd. All rights reserved.

Vx-770 potentiates CFTR function by promoting decoupling between the gating cycle and ATP hydrolysis cycle.

PubMed

Jih, Kang-Yang; Hwang, Tzyh-Chang

2013-03-12

Vx-770 (Ivacaftor), a Food and Drug Administration (FDA)-approved drug for clinical application to patients with cystic fibrosis (CF), shifts the paradigm from conventional symptomatic treatments to therapeutics directly tackling the root of the disease: functional defects of the cystic fibrosis transmembrane conductance regulator (CFTR) chloride channel caused by pathogenic mutations. The underlying mechanism for the action of Vx-770 remains elusive partly because this compound not only increases the activity of wild-type (WT) channels whose gating is primarily controlled by ATP binding/hydrolysis, but also improves the function of G551D-CFTR, a disease-associated mutation that abolishes CFTR's responsiveness to ATP. Here we provide a unified theory to account for this dual effect of Vx-770. We found that Vx-770 enhances spontaneous, ATP-independent activity of WT-CFTR to a similar magnitude as its effects on G551D channels, a result essentially explaining Vx-770's effect on G551D-CFTR. Furthermore, Vx-770 increases the open time of WT-CFTR in an [ATP]-dependent manner. This distinct kinetic effect is accountable with a newly proposed CFTR gating model depicting an [ATP]-dependent "reentry" mechanism that allows CFTR shuffling among different open states by undergoing multiple rounds of ATP hydrolysis. We further examined the effect of Vx-770 on R352C-CFTR, a unique mutant that allows direct observation of hydrolysis-triggered gating events. Our data corroborate that Vx-770 increases the open time of WT-CFTR by stabilizing a posthydrolytic open state and thereby fosters decoupling between the gating cycle and ATP hydrolysis cycle. The current study also suggests that this unique mechanism of drug action can be further exploited to develop strategies that enhance the function of CFTR.

Vx-770 potentiates CFTR function by promoting decoupling between the gating cycle and ATP hydrolysis cycle

PubMed Central

Jih, Kang-Yang; Hwang, Tzyh-Chang

2013-01-01

Vx-770 (Ivacaftor), a Food and Drug Administration (FDA)-approved drug for clinical application to patients with cystic fibrosis (CF), shifts the paradigm from conventional symptomatic treatments to therapeutics directly tackling the root of the disease: functional defects of the cystic fibrosis transmembrane conductance regulator (CFTR) chloride channel caused by pathogenic mutations. The underlying mechanism for the action of Vx-770 remains elusive partly because this compound not only increases the activity of wild-type (WT) channels whose gating is primarily controlled by ATP binding/hydrolysis, but also improves the function of G551D-CFTR, a disease-associated mutation that abolishes CFTR’s responsiveness to ATP. Here we provide a unified theory to account for this dual effect of Vx-770. We found that Vx-770 enhances spontaneous, ATP-independent activity of WT-CFTR to a similar magnitude as its effects on G551D channels, a result essentially explaining Vx-770’s effect on G551D-CFTR. Furthermore, Vx-770 increases the open time of WT-CFTR in an [ATP]-dependent manner. This distinct kinetic effect is accountable with a newly proposed CFTR gating model depicting an [ATP]-dependent “reentry” mechanism that allows CFTR shuffling among different open states by undergoing multiple rounds of ATP hydrolysis. We further examined the effect of Vx-770 on R352C-CFTR, a unique mutant that allows direct observation of hydrolysis-triggered gating events. Our data corroborate that Vx-770 increases the open time of WT-CFTR by stabilizing a posthydrolytic open state and thereby fosters decoupling between the gating cycle and ATP hydrolysis cycle. The current study also suggests that this unique mechanism of drug action can be further exploited to develop strategies that enhance the function of CFTR. PMID:23440202

Dissolved organic carbon export and internal cycling in small, headwater lakes

USGS Publications Warehouse

Stets, Edward G.; Striegl, Robert G.; Aiken, George R.

2010-01-01

Carbon (C) cycling in freshwater lakes is intense but poorly integrated into our current understanding of overall C transport from the land to the oceans. We quantified dissolved organic carbon export (DOCX) and compared it with modeled gross DOC mineralization (DOCR) to determine whether hydrologic or within-lake processes dominated DOC cycling in a small headwaters watershed in Minnesota, USA. We also used DOC optical properties to gather information about DOC sources. We then compared our results to a data set of approximately 1500 lakes in the Eastern USA (Eastern Lake Survey, ELS, data set) to place our results in context of lakes more broadly. In the open-basin lakes in our watershed (n = 5), DOCX ranged from 60 to 183 g C m−2 lake area yr−1, whereas DOCR ranged from 15 to 21 g C m−2 lake area yr−1, emphasizing that lateral DOC fluxes dominated. DOCX calculated in our study watershed clustered near the 75th percentile of open-basin lakes in the ELS data set, suggesting that these results were not unusual. In contrast, DOCX in closed-basin lakes (n = 2) was approximately 5 g C m−2 lake area yr−1, whereas DOCR was 37 to 42 g C m−2 lake area yr−1, suggesting that internal C cycling dominated. In the ELS data set, median DOCX was 32 and 12 g C m−2 yr−1 in open-basin and closed-basin lakes, respectively. Although not as high as what was observed in our study watershed, DOCX is an important component of lake C flux more generally, particularly in open-basin lakes.

Solar Cycle variations in Earth's open flux content measured by the SuperDARN radar network

NASA Astrophysics Data System (ADS)

Imber, S. M.; Milan, S. E.; Lester, M.

2013-09-01

We present a long term study, from 1996 - 2012, of the latitude of the Heppner-Maynard Boundary (HMB) determined using the northern hemisphere SuperDARN radars. The HMB represents the equatorward extent of ionospheric convection and is here used as a proxy for the amount of open flux in the polar cap. The mean HMB latitude (measured at midnight) is found to be at 64 degrees during the entire period, with secondary peaks at lower latitudes during the solar maximum of 2003, and at higher latitudes during the recent extreme solar minimum of 2008-2011. We associate these large scale statistical variations in open flux content with solar cycle variations in the solar wind parameters leading to changes in the intensity of the coupling between the solar wind and the magnetosphere.

Open cycle ocean thermal energy conversion system structure

DOEpatents

Wittig, J. Michael

1980-01-01

A generally mushroom-shaped, open cycle OTEC system and distilled water producer which has a skirt-conduit structure extending from the enlarged portion of the mushroom to the ocean. The enlarged part of the mushroom houses a toroidal casing flash evaporator which produces steam which expands through a vertical rotor turbine, partially situated in the center of the blossom portion and partially situated in the mushroom's stem portion. Upon expansion through the turbine, the motive steam enters a shell and tube condenser annularly disposed about the rotor axis and axially situated beneath the turbine in the stem portion. Relatively warm ocean water is circulated up through the radially outer skirt-conduit structure entering the evaporator through a radially outer portion thereof, flashing a portion thereof into motive steam, and draining the unflashed portion from the evaporator through a radially inner skirt-conduit structure. Relatively cold cooling water enters the annular condenser through the radially inner edge and travels radially outwardly into a channel situated along the radially outer edge of the condenser. The channel is also included in the radially inner skirt-conduit structure. The cooling water is segregated from the potable, motive steam condensate which can be used for human consumption or other processes requiring high purity water. The expansion energy of the motive steam is partially converted into rotational mechanical energy of the turbine rotor when the steam is expanded through the shaft attached blades. Such mechanical energy drives a generator also included in the enlarged mushroom portion for producing electrical energy. Such power generation equipment arrangement provides a compact power system from which additional benefits may be obtained by fabricating the enclosing equipment, housings and component casings from low density materials, such as prestressed concrete, to permit those casings and housings to also function as a floating support vessel.

Relationship between masticatory performance using a gummy jelly and masticatory movement.

PubMed

Uesugi, Hanako; Shiga, Hiroshi

2017-10-01

The purpose of this study was to clarify the relationship between masticatory performance using a gummy jelly and masticatory movement. Thirty healthy males were asked to chew a gummy jelly on their habitual chewing side for 20s, and the parameters of masticatory performance and masticatory movement were calculated as follows. For evaluating the masticatory performance, the amount of glucose extraction during chewing of a gummy jelly was measured. For evaluating the masticatory movement, the movement of the mandibular incisal point was recorded using the MKG K6-I, and ten parameters of the movement path (opening distance and masticatory width), movement rhythm (opening time, closing time, occluding time, and cycle time), stability of movement (stability of path and stability of rhythm), and movement velocity (opening maximum velocity and closing maximum velocity) were calculated from 10 cycles of chewing beginning with the fifth cycle. The relationship between the amount of glucose extraction and parameters representing masticatory movement was investigated and then stepwise multiple linear regression analysis was performed. The amount of glucose extraction was associated with 7 parameters representing the masticatory movement. Stepwise multiple linear regression analysis showed that the opening distance, closing time, stability of rhythm, and closing maximum velocity were the most important factors affecting the glucose extraction. From these results it was suggested that there was a close relation between masticatory performance and masticatory movement, and that the masticatory performance could be increased by rhythmic, rapid and stable mastication with a large opening distance. Copyright © 2017 Japan Prosthodontic Society. Published by Elsevier Ltd. All rights reserved.

Intricate but tight coupling of spiracular activity and abdominal ventilation during locust discontinuous gas exchange cycles.

PubMed

Talal, Stav; Gefen, Eran; Ayali, Amir

2018-03-15

Discontinuous gas exchange (DGE) is the best studied among insect gas exchange patterns. DGE cycles comprise three phases, which are defined by their spiracular state: closed, flutter and open. However, spiracle status has rarely been monitored directly; rather, it is often assumed based on CO 2 emission traces. In this study, we directly recorded electromyogram (EMG) signals from the closer muscle of the second thoracic spiracle and from abdominal ventilation muscles in a fully intact locust during DGE. Muscular activity was monitored simultaneously with CO 2 emission, under normoxia and under various experimental oxic conditions. Our findings indicate that locust DGE does not correspond well with the commonly described three-phase cycle. We describe unique DGE-related ventilation motor patterns, coupled to spiracular activity. During the open phase, when CO 2 emission rate is highest, the thoracic spiracles do not remain open; rather, they open and close rapidly. This fast spiracle activity coincides with in-phase abdominal ventilation, while alternating with the abdominal spiracle and thus facilitating a unidirectional air flow along the main trachea. A change in the frequency of rhythmic ventilation during the open phase suggests modulation by intra-tracheal CO 2 levels. A second, slow ventilatory movement pattern probably serves to facilitate gas diffusion during spiracle closure. Two flutter-like patterns are described in association with the different types of ventilatory activity. We offer a modified mechanistic model for DGE in actively ventilating insects, incorporating ventilatory behavior and changes in spiracle state. © 2018. Published by The Company of Biologists Ltd.

Integration of photovoltaic and concentrated solar thermal technologies for H2 production by the hybrid sulfur cycle

NASA Astrophysics Data System (ADS)

Liberatore, Raffaele; Ferrara, Mariarosaria; Lanchi, Michela; Turchetti, Luca

2017-06-01

It is widely agreed that hydrogen used as energy carrier and/or storage media may significantly contribute in the reduction of emissions, especially if produced by renewable energy sources. The Hybrid Sulfur (HyS) cycle is considered as one of the most promising processes to produce hydrogen through the water-splitting process. The FP7 project SOL2HY2 (Solar to Hydrogen Hybrid Cycles) investigates innovative material and process solutions for the use of solar heat and power in the HyS process. A significant part of the SOL2HY2 project is devoted to the analysis and optimization of the integration of the solar and chemical (hydrogen production) plants. In this context, this work investigates the possibility to integrate different solar technologies, namely photovoltaic, solar central receiver and solar troughs, to optimize their use in the HyS cycle for a green hydrogen production, both in the open and closed process configurations. The analysis carried out accounts for different combinations of geographical location and plant sizing criteria. The use of a sulfur burner, which can serve both as thermal backup and SO2 source for the open cycle, is also considered.

To Recycle or Not to Recycle? An Intergenerational Approach to Nuclear Fuel Cycles

PubMed Central

Kloosterman, Jan Leen

2007-01-01

This paper approaches the choice between the open and closed nuclear fuel cycles as a matter of intergenerational justice, by revealing the value conflicts in the production of nuclear energy. The closed fuel cycle improve sustainability in terms of the supply certainty of uranium and involves less long-term radiological risks and proliferation concerns. However, it compromises short-term public health and safety and security, due to the separation of plutonium. The trade-offs in nuclear energy are reducible to a chief trade-off between the present and the future. To what extent should we take care of our produced nuclear waste and to what extent should we accept additional risks to the present generation, in order to diminish the exposure of future generation to those risks? The advocates of the open fuel cycle should explain why they are willing to transfer all the risks for a very long period of time (200,000 years) to future generations. In addition, supporters of the closed fuel cycle should underpin their acceptance of additional risks to the present generation and make the actual reduction of risk to the future plausible. PMID:18075732

To recycle or not to recycle? An intergenerational approach to nuclear fuel cycles.

PubMed

Taebi, Behnam; Kloosterman, Jan Leen

2008-06-01

This paper approaches the choice between the open and closed nuclear fuel cycles as a matter of intergenerational justice, by revealing the value conflicts in the production of nuclear energy. The closed fuel cycle improve sustainability in terms of the supply certainty of uranium and involves less long-term radiological risks and proliferation concerns. However, it compromises short-term public health and safety and security, due to the separation of plutonium. The trade-offs in nuclear energy are reducible to a chief trade-off between the present and the future. To what extent should we take care of our produced nuclear waste and to what extent should we accept additional risks to the present generation, in order to diminish the exposure of future generation to those risks? The advocates of the open fuel cycle should explain why they are willing to transfer all the risks for a very long period of time (200,000 years) to future generations. In addition, supporters of the closed fuel cycle should underpin their acceptance of additional risks to the present generation and make the actual reduction of risk to the future plausible.

NTCP opens the door for hepatitis B virus infection.

PubMed

Yan, Huan; Liu, Yang; Sui, Jianhua; Li, Wenhui

2015-09-01

A liver bile acids transporter, sodium taurocholate cotransporting polypeptide (NTCP, encoded by SLC10A1) was recently identified as a functional receptor for hepatitis B virus (HBV) and its satellite hepatitis D virus (HDV). NTCP-complemented human hepatoma HepG2 cells (HepG2-NTCP) were shown to support infection of HBV and HDV in vitro, providing a much-needed and convenient cell culture system for the viruses. Identification of NTCP as a functional receptor for HBV has significantly advanced our understanding of the viral life cycle and opened new opportunities for developing anti-HBV interventions. This article forms part of a symposium in Antiviral Research on "An unfinished story: from the discovery of the Australia antigen to the development of new curative therapies for hepatitis B". Copyright © 2015 Elsevier B.V. All rights reserved.

Study of seed reprocessing systems for open cycle coal fired MHD power plants. Task 1: Selection of processes for more detailed study

NASA Astrophysics Data System (ADS)

1980-07-01

In most of the processes, a portion of the potassium seed material is converted to a compound not containing sulfur. The potassium in this form can, when injected upstream of the MHD channel, capture the sulfur released during the combustion of coal and eliminate the need for flue gas desulfurization equipment. Criteria considered in the evaluation included cost, state of development, seed loss, power requirements, availability, durability, key component risk, environmental impact, safety, controllability, and impurities buildup.

Mixed Single/Double Precision in OpenIFS: A Detailed Study of Energy Savings, Scaling Effects, Architectural Effects, and Compilation Effects

NASA Astrophysics Data System (ADS)

Fagan, Mike; Dueben, Peter; Palem, Krishna; Carver, Glenn; Chantry, Matthew; Palmer, Tim; Schlacter, Jeremy

2017-04-01

It has been shown that a mixed precision approach that judiciously replaces double precision with single precision calculations can speed-up global simulations. In particular, a mixed precision variation of the Integrated Forecast System (IFS) of the European Centre for Medium-Range Weather Forecasts (ECMWF) showed virtually the same quality model results as the standard double precision version (Vana et al., Single precision in weather forecasting models: An evaluation with the IFS, Monthly Weather Review, in print). In this study, we perform detailed measurements of savings in computing time and energy using a mixed precision variation of the -OpenIFS- model. The mixed precision variation of OpenIFS is analogous to the IFS variation used in Vana et al. We (1) present results for energy measurements for simulations in single and double precision using Intel's RAPL technology, (2) conduct a -scaling- study to quantify the effects that increasing model resolution has on both energy dissipation and computing cycles, (3) analyze the differences between single core and multicore processing, and (4) compare the effects of different compiler technologies on the mixed precision OpenIFS code. In particular, we compare intel icc/ifort with gnu gcc/gfortran.

AFB/open cycle gas turbine conceptual design study

NASA Technical Reports Server (NTRS)

Dickinson, T. W.; Tashjian, R.

1983-01-01

Applications of coal fired atmospheric fluidized bed gas turbine systems in industrial cogeneration are identified. Based on site-specific conceptual designs, the potential benefits of the AFB/gas turbine system were compared with an atmospheric fluidized design steam boiler/steam turbine system. The application of these cogeneration systems at four industrial plant sites is reviewed. A performance and benefit analysis was made along with a study of the representativeness of the sites both in regard to their own industry and compared to industry as a whole. A site was selected for the conceptual design, which included detailed site definition, AFB/gas turbine and AFB/steam turbine cogeneration system designs, detailed cost estimates, and comparative performance and benefit analysis. Market and benefit analyses identified the potential market penetration for the cogeneration technologies and quantified the potential benefits.

AFB/open cycle gas turbine conceptual design study

NASA Astrophysics Data System (ADS)

Dickinson, T. W.; Tashjian, R.

1983-09-01

Applications of coal fired atmospheric fluidized bed gas turbine systems in industrial cogeneration are identified. Based on site-specific conceptual designs, the potential benefits of the AFB/gas turbine system were compared with an atmospheric fluidized design steam boiler/steam turbine system. The application of these cogeneration systems at four industrial plant sites is reviewed. A performance and benefit analysis was made along with a study of the representativeness of the sites both in regard to their own industry and compared to industry as a whole. A site was selected for the conceptual design, which included detailed site definition, AFB/gas turbine and AFB/steam turbine cogeneration system designs, detailed cost estimates, and comparative performance and benefit analysis. Market and benefit analyses identified the potential market penetration for the cogeneration technologies and quantified the potential benefits.

Endogenous and exogenous control of ecosystem function: N cycling in headwater streams.

PubMed

Valett, H M; Thomas, S A; Mulholland, P J; Webster, J R; Dahm, C N; Fellows, C S; Crenshaw, C L; Peterson, C G

2008-12-01

Allochthonous inputs act as resource subsidies to many ecosystems, where they exert strong influences on metabolism and material cycling. At the same time, metabolic theory proposes endogenous thermal control independent of resource supply. To address the relative importance of exogenous and endogenous influences, we quantified spatial and temporal variation in ecosystem metabolism and nitrogen (N) uptake using seasonal releases of 15N as nitrate in six streams differing in riparian-stream interaction and metabolic character. Nitrate removal was quantified using a nutrient spiraling approach based on measurements of downstream decline in 15N flux. Respiration (R) and gross primary production (GPP) were measured with whole-stream diel oxygen budgets. Uptake and metabolism metrics were addressed as z scores relative to site means to assess temporal variation. In open-canopied streams, areal uptake (U; microg N x m(-2) x s(-1)) was closely related to GPP, metabolic rates increased with temperature, and R was accurately predicted by metabolic scaling relationships. In forested streams, N spiraling was not related to GPP; instead, uptake velocity (v(f); mm/s) was closely related to R. In contrast to open-canopied streams, N uptake and metabolic activity were negatively correlated to temperature and poorly described by scaling laws. We contend that streams differ along a gradient of exogenous and endogenous control that relates to the relative influences of resource subsidies and in-stream energetics as determinants of seasonal patterns of metabolism and N cycling. Our research suggests that temporal variation in the propagation of ecological influence between adjacent systems generates phases when ecosystems are alternatively characterized as endogenously and exogenously controlled.

Coronal and heliospheric magnetic flux circulation and its relation to open solar flux evolution

NASA Astrophysics Data System (ADS)

Lockwood, Mike; Owens, Mathew J.; Imber, Suzanne M.; James, Matthew K.; Bunce, Emma J.; Yeoman, Timothy K.

2017-06-01

Solar cycle 24 is notable for three features that can be found in previous cycles but which have been unusually prominent: (1) sunspot activity was considerably greater in the northern/southern hemisphere during the rising/declining phase; (2) accumulation of open solar flux (OSF) during the rising phase was modest, but rapid in the early declining phase; (3) the heliospheric current sheet (HCS) tilt showed large fluctuations. We show that these features had a major influence on the progression of the cycle. All flux emergence causes a rise then a fall in OSF, but only OSF with foot points in opposing hemispheres progresses the solar cycle via the evolution of the polar fields. Emergence in one hemisphere, or symmetric emergence without some form of foot point exchange across the heliographic equator, causes poleward migrating fields of both polarities in one or both (respectively) hemispheres which temporarily enhance OSF but do not advance the polar field cycle. The heliospheric field observed near Mercury and Earth reflects the asymmetries in emergence. Using magnetograms, we find evidence that the poleward magnetic flux transport (of both polarities) is modulated by the HCS tilt, revealing an effect on OSF loss rate. The declining phase rise in OSF was caused by strong emergence in the southern hemisphere with an anomalously low HCS tilt. This implies the recent fall in the southern polar field will be sustained and that the peak OSF has limited implications for the polar field at the next sunspot minimum and hence for the amplitude of cycle 25.