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Sample records for concept le cycle

  1. Life cycle planning: An evolving concept

    SciTech Connect

    Moore, P.J.R.; Gorman, I.G.

    1994-12-31

    Life-cycle planning is an evolving concept in the management of oil and gas projects. BHP Petroleum now interprets this idea to include all development planning from discovery and field appraisal to final abandonment and includes safety, environmental, technical, plant, regulatory, and staffing issues. This article describes in the context of the Timor Sea, how despite initial successes and continuing facilities upgrades, BHPP came to perceive that current operations could be the victim of early development successes, particularly in the areas of corrosion and maintenance. The search for analogies elsewhere lead to the UK North Sea, including the experiences of Britoil and BP, both of which performed detailed Life of Field studies in the later eighties. These materials have been used to construct a format and content for total Life-cycle plans in general and the social changes required to ensure their successful application in Timor Sea operations and deployment throughout Australia.

  2. Supercritical Brayton Cycle Nuclear Power System Concepts

    SciTech Connect

    Wright, Steven A.

    2007-01-30

    Both the NASA and DOE have programs that are investigating advanced power conversion cycles for planetary surface power on the moon or Mars, and for next generation nuclear power plants on earth. The gas Brayton cycle offers many practical solutions for space nuclear power systems and was selected as the nuclear power system of choice for the NASA Prometheus project. An alternative Brayton cycle that offers high efficiency at a lower reactor coolant outlet temperature is the supercritical Brayton cycle (SCBC). The supercritical cycle is a true Brayton cycle because it uses a single phase fluid with a compressor inlet temperature that is just above the critical point of the fluid. This paper describes the use of a supercritical Brayton cycle that achieves a cycle efficiency of 26.6% with a peak coolant temperature of 750 K and for a compressor inlet temperature of 390 K. The working fluid uses a clear odorless, nontoxic refrigerant C318 perflurocarbon (C4F8) that always operates in the gas phase. This coolant was selected because it has a critical temperature and pressure of 388.38 K and 2.777 MPa. The relatively high critical temperature allows for efficient thermal radiation that keeps the radiator mass small. The SCBC achieves high efficiency because the loop design takes advantage of the non-ideal nature of the coolant equation of state just above the critical point. The lower coolant temperature means that metal fuels, uranium oxide fuels, and uranium zirconium hydride fuels with stainless steel, ferretic steel, or superalloy cladding can be used with little mass penalty or reduction in cycle efficiency. The reactor can use liquid-metal coolants and no high temperature heat exchangers need to be developed. Indirect gas cooling or perhaps even direct gas cooling can be used if the C4F8 coolant is found to be sufficiently radiation tolerant. Other fluids can also be used in the supercritical Brayton cycle including Propane (C3H8, Tcritical = 369 K) and Hexane (C6

  3. Supercritical Brayton Cycle Nuclear Power System Concepts

    NASA Astrophysics Data System (ADS)

    Wright, Steven A.

    2007-01-01

    Both the NASA and DOE have programs that are investigating advanced power conversion cycles for planetary surface power on the moon or Mars, and for next generation nuclear power plants on earth. The gas Brayton cycle offers many practical solutions for space nuclear power systems and was selected as the nuclear power system of choice for the NASA Prometheus project. An alternative Brayton cycle that offers high efficiency at a lower reactor coolant outlet temperature is the supercritical Brayton cycle (SCBC). The supercritical cycle is a true Brayton cycle because it uses a single phase fluid with a compressor inlet temperature that is just above the critical point of the fluid. This paper describes the use of a supercritical Brayton cycle that achieves a cycle efficiency of 26.6% with a peak coolant temperature of 750 K and for a compressor inlet temperature of 390 K. The working fluid uses a clear odorless, nontoxic refrigerant C318 perflurocarbon (C4F8) that always operates in the gas phase. This coolant was selected because it has a critical temperature and pressure of 388.38 K and 2.777 MPa. The relatively high critical temperature allows for efficient thermal radiation that keeps the radiator mass small. The SCBC achieves high efficiency because the loop design takes advantage of the non-ideal nature of the coolant equation of state just above the critical point. The lower coolant temperature means that metal fuels, uranium oxide fuels, and uranium zirconium hydride fuels with stainless steel, ferretic steel, or superalloy cladding can be used with little mass penalty or reduction in cycle efficiency. The reactor can use liquid-metal coolants and no high temperature heat exchangers need to be developed. Indirect gas cooling or perhaps even direct gas cooling can be used if the C4F8 coolant is found to be sufficiently radiation tolerant. Other fluids can also be used in the supercritical Brayton cycle including Propane (C3H8, Tcritical = 369 K) and Hexane (C6

  4. Le concept de banque d'items et ses implications sur le contenu didactique

    NASA Astrophysics Data System (ADS)

    Tistaert, G.; Mwene, Magabe

    1985-12-01

    The development of the concept of an item bank comes as a reply to the didactic situations which for reasons of efficiency require the storing of a number of susceptible items to be used at any time. Access to the computer makes possible an improvement and rationalization of the management of the item bank. At the same time the extension of the concept has followed two main directions. On the one hand, particular care relates to the adequacy of stored items with the content of learning and it brings about the emergence of a technology of item-editing. On the other hand, psychometric considerations have caused the invariance of essential characteristics of the items. This demands that the items respond to the presupposed models with latent traits. On the basis of theoretical arguments supported by some research findings the final part of the article calls attention to the deep discord among researchers concerning the reliability of the presuppositions of these models in the didactic field. The compromise will probably lead to it that the multidimensionality of items which have a didactic character are admitted.

  5. Integrating Concept Mapping and the Learning Cycle To Teach Diffusion and Osmosis Concepts to High School Biology Students.

    ERIC Educational Resources Information Center

    Odom, Arthur L.; Kelly, Paul V.

    2001-01-01

    Explores the effectiveness of concept mapping, the learning cycle, expository instruction, and a combination of concept mapping/learning cycle in promoting conceptual understanding of diffusion and osmosis. Concludes that the concept mapping/learning cycle and concept mapping treatment groups significantly outperformed the expository treatment…

  6. Integrating the disaster cycle model into traditional disaster diplomacy concepts.

    PubMed

    Callaway, David W; Yim, Eugene S; Stack, Colin; Burkle, Frederick M

    2012-03-01

    Disaster diplomacy is an evolving contemporary model that examines how disaster response strategies can facilitate cooperation between parties in conflict. The concept of disaster diplomacy has emerged during the past decade to address how disaster response can be leveraged to promote peace, facilitate communication, promote human rights, and strengthen intercommunity ties in the increasingly multipolar modern world. Historically, the concept has evolved through two camps, one that focuses on the interactions between national governments in conflict and another that emphasizes the grassroots movements that can promote change. The two divergent approaches can be reconciled and disaster diplomacy further matured by contextualizing the concept within the disaster cycle, a model well established within the disaster risk management community. In particular, access to available health care, especially for the most vulnerable populations, may need to be negotiated. As such, disaster response professionals, including emergency medicine specialists, can play an important role in the development and implementation of disaster diplomacy concepts. PMID:22490937

  7. Generic Repository Concepts and Thermal Analysis for Advanced Fuel Cycles

    SciTech Connect

    Hardin, Ernest; Blink, James; Carter, Joe; Massimiliano, Fratoni; Greenberg, Harris; Howard, Rob L

    2011-01-01

    The current posture of the used nuclear fuel management program in the U.S. following termination of the Yucca Mountain Project, is to pursue research and development (R&D) of generic (i.e., non-site specific) technologies for storage, transportation and disposal. Disposal R&D is directed toward understanding and demonstrating the performance of reference geologic disposal concepts selected to represent the current state-of-the-art in geologic disposal. One of the principal constraints on waste packaging and emplacement in a geologic repository is management of the waste-generated heat. This paper describes the selection of reference disposal concepts, and thermal management strategies for waste from advanced fuel cycles. A geologic disposal concept for spent nuclear fuel (SNF) or high-level waste (HLW) consists of three components: waste inventory, geologic setting, and concept of operations. A set of reference geologic disposal concepts has been developed by the U.S. Department of Energy (DOE) Used Fuel Disposition Campaign, for crystalline rock, clay/shale, bedded salt, and deep borehole (crystalline basement) geologic settings. We performed thermal analysis of these concepts using waste inventory cases representing a range of advanced fuel cycles. Concepts of operation consisting of emplacement mode, repository layout, and engineered barrier descriptions, were selected based on international progress and previous experience in the U.S. repository program. All of the disposal concepts selected for this study use enclosed emplacement modes, whereby waste packages are in direct contact with encapsulating engineered or natural materials. The encapsulating materials (typically clay-based or rock salt) have low intrinsic permeability and plastic rheology that closes voids so that low permeability is maintained. Uniformly low permeability also contributes to chemically reducing conditions common in soft clay, shale, and salt formations. Enclosed modes are associated

  8. Concepts and tools for the software life cycle

    NASA Astrophysics Data System (ADS)

    Tausworthe, Robert C.

    1985-10-01

    The life cycle process for large software-intensive systems is an extremely intricate and complex process involving many people performing amid a very large base of evolving computer programs, documentation and data. To be successful, the process must be well conceived, planned and conducted; however, the nature of scientific and other high-technology projects involving large-scale software is such that conceptualization, planning and implementation to the degree of detail required is so laborintensive and unmotivating as to be counter-productive and seldom cost-effective. The tools, techniques and aids needed to engineer, manage and administrate a large software-intensive task are themselves parts of a large software base, and are incurred only at great expense. This paper focuses on the needs of the software life cycle in terms of supporting tools and methodologies. The concept of a distributed network for engineering, management and administrative functions for engineering, management and administrative functions is outlined, and the key characteristics of localized subnets in high-communications-traffic areas of software activity are discussed. A formal, deliberate, structured, systems-engineered approach toward the construction of uniform, coordinated tools is proposed as a means to reduce development and maintenance costs, foster creativity, enhance reliability, promote standardization and sustain human motivation.

  9. Concept of DT fuel cycle for a fusion neutron source

    SciTech Connect

    Anan'ev, S.; Spitsyn, A.V.; Kuteev, B.V.; Cherkez, D.I.; Shirnin, P.N.; Kazakovsky, N.T.

    2015-03-15

    A concept of DT-fusion neutron source (FNS) with the neutron yield higher than 10{sup 18} neutrons per second is under design in Russia. Such a FNS is of interest for many applications: 1) basic and applied research (neutron scattering, etc); 2) testing the structural materials for fusion reactors; 3) control of sub-critical nuclear systems and 4) nuclear waste processing (including transmutation of minor actinides). This paper describes the fuel cycle concept of a compact fusion neutron source based on a small spherical tokamak (FNS-ST) with a MW range of DT fusion power and considers the key physics issues of this device. The major and minor radii are ∼0.5 and ∼0.3 m, magnetic field ∼1.5 T, heating power less than 15 MW and plasma current 1-2 MA. The system provides the fuel mixture with equal fractions of D and T (D:T = 1:1) for all FNS technology systems. (authors)

  10. Some heat pump concepts for residual heat utilization. [Absorption-cycle and open-cycle systems

    SciTech Connect

    Perez-Blanco, H.; Chen, F. C.

    1980-01-01

    Large quantities of low temperature heat in the industrial sector are rejected in the cooling water, condensate, and process water streams. While the energy rejected in these streams at temperatures between 40 and 80/sup 0/C amounts to 2.95 x 10/sup 9/ GJ/y, 2.42 x 10/sup 9/ GJ/y of process energy in the form of hot water and steam are needed in the United States. Industrial heat pumps, that recover the low temperature heat energy and upgrade it to a more usable temperature level, may improve the energy supply and demand situation. Two heat activated heat pump concepts - an absorption cycle system and an open cycle system are analyzed from the conceptual systems design and energy savings point of view. The results of the analysis and further research needs are presented.

  11. Rocket-Based Combined Cycle Engine Concept Development

    NASA Technical Reports Server (NTRS)

    Ratekin, G.; Goldman, Allen; Ortwerth, P.; Weisberg, S.; McArthur, J. Craig (Technical Monitor)

    2001-01-01

    The development of rocket-based combined cycle (RBCC) propulsion systems is part of a 12 year effort under both company funding and contract work. The concept is a fixed geometry integrated rocket, ramjet, scramjet, which is hydrogen fueled and uses hydrogen regenerative cooling. The baseline engine structural configuration uses an integral structure that eliminates panel seals, seal purge gas, and closeout side attachments. Engine A5 is the current configuration for NASA Marshall Space Flight Center (MSFC) for the ART program. Engine A5 models the complete flight engine flowpath of inlet, isolator, airbreathing combustor, and nozzle. High-performance rocket thrusters are integrated into the engine enabling both low speed air-augmented rocket (AAR) and high speed pure rocket operation. Engine A5 was tested in GASL's new Flight Acceleration Simulation Test (FAST) facility in all four operating modes, AAR, RAM, SCRAM, and Rocket. Additionally, transition from AAR to RAM and RAM to SCRAM was also demonstrated. Measured performance demonstrated vision vehicle performance levels for Mach 3 AAR operation and ramjet operation from Mach 3 to 4. SCRAM and rocket mode performance was above predictions. For the first time, testing also demonstrated transition between operating modes.

  12. Technology Insights and Perspectives for Nuclear Fuel Cycle Concepts

    SciTech Connect

    S. Bays; S. Piet; N. Soelberg; M. Lineberry; B. Dixon

    2010-09-01

    The following report provides a rich resource of information for exploring fuel cycle characteristics. The most noteworthy trends can be traced back to the utilization efficiency of natural uranium resources. By definition, complete uranium utilization occurs only when all of the natural uranium resource can be introduced into the nuclear reactor long enough for all of it to undergo fission. Achieving near complete uranium utilization requires technologies that can achieve full recycle or at least nearly full recycle of the initial natural uranium consumed from the Earth. Greater than 99% of all natural uranium is fertile, and thus is not conducive to fission. This fact requires the fuel cycle to convert large quantities of non-fissile material into fissile transuranics. Step increases in waste benefits are closely related to the step increase in uranium utilization going from non-breeding fuel cycles to breeding fuel cycles. The amount of mass requiring a disposal path is tightly coupled to the quantity of actinides in the waste stream. Complete uranium utilization by definition means that zero (practically, near zero) actinide mass is present in the waste stream. Therefore, fuel cycles with complete (uranium and transuranic) recycle discharge predominately fission products with some actinide process losses. Fuel cycles without complete recycle discharge a much more massive waste stream because only a fraction of the initial actinide mass is burned prior to disposal. In a nuclear growth scenario, the relevant acceptable frequency for core damage events in nuclear reactors is inversely proportional to the number of reactors deployed in a fuel cycle. For ten times the reactors in a fleet, it should be expected that the fleet-average core damage frequency be decreased by a factor of ten. The relevant proliferation resistance of a fuel cycle system is enhanced with: decreasing reliance on domestic fuel cycle services, decreasing adaptability for technology misuse

  13. INTEGRATED PYROLYSIS COMBINED CYCLE BIOMASS POWER SYSTEM CONCEPT DEFINITION

    SciTech Connect

    Eric Sandvig; Gary Walling; Robert C. Brown; Ryan Pletka; Desmond Radlein; Warren Johnson

    2003-03-01

    Advanced power systems based on integrated gasification/combined cycles (IGCC) are often presented as a solution to the present shortcomings of biomass as fuel. Although IGCC has been technically demonstrated at full scale, it has not been adopted for commercial power generation. Part of the reason for this situation is the continuing low price for coal. However, another significant barrier to IGCC is the high level of integration of this technology: the gas output from the gasifier must be perfectly matched to the energy demand of the gas turbine cycle. We are developing an alternative to IGCC for biomass power: the integrated (fast) pyrolysis/ combined cycle (IPCC). In this system solid biomass is converted into liquid rather than gaseous fuel. This liquid fuel, called bio-oil, is a mixture of oxygenated organic compounds and water that serves as fuel for a gas turbine topping cycle. Waste heat from the gas turbine provides thermal energy to the steam turbine bottoming cycle. Advantages of the biomass-fueled IPCC system include: combined cycle efficiency exceeding 37 percent efficiency for a system as small as 7.6 MW{sub e}; absence of high pressure thermal reactors; decoupling of fuel processing and power generation; and opportunities for recovering value-added products from the bio-oil. This report provides a technical overview of the system including pyrolyzer design, fuel clean-up strategies, pyrolysate condenser design, opportunities for recovering pyrolysis byproducts, gas turbine cycle design, and Rankine steam cycle. The report also reviews the potential biomass fuel supply in Iowa, provide and economic analysis, and present a summery of benefits from the proposed system.

  14. Supercritical CO2 direct cycle Gas Fast Reactor (SC-GFR) concept.

    SciTech Connect

    Wright, Steven Alan; Parma, Edward J., Jr.; Suo-Anttila, Ahti Jorma; Al Rashdan, Ahmad; Tsvetkov, Pavel Valeryevich; Vernon, Milton E.; Fleming, Darryn D.; Rochau, Gary Eugene

    2011-05-01

    This report describes the supercritical carbon dioxide (S-CO{sub 2}) direct cycle gas fast reactor (SC-GFR) concept. The SC-GFR reactor concept was developed to determine the feasibility of a right size reactor (RSR) type concept using S-CO{sub 2} as the working fluid in a direct cycle fast reactor. Scoping analyses were performed for a 200 to 400 MWth reactor and an S-CO{sub 2} Brayton cycle. Although a significant amount of work is still required, this type of reactor concept maintains some potentially significant advantages over ideal gas-cooled systems and liquid metal-cooled systems. The analyses presented in this report show that a relatively small long-life reactor core could be developed that maintains decay heat removal by natural circulation. The concept is based largely on the Advanced Gas Reactor (AGR) commercial power plants operated in the United Kingdom and other GFR concepts.

  15. Application of the N-Streaming SM concept to Peach Bottom 2 Cycle 17

    SciTech Connect

    Asgari, M.; Kropaczek, D. J.; Oyarzun, C. C.

    2006-07-01

    This paper discusses the application of the N-Streaming concept developed at Global Nuclear Fuel for the design of a Boiling Water Reactor (BWR) fuel cycle. The paper presents the N-Streaming concept and discusses the application of N-Streaming to the recent fuel cycle for Peach Bottom Unit 2 Cycle 17. It is demonstrated that the application of N-Streaming provides extra design freedom to optimize design margins allowing better operational flexibility while reducing the fuel cycle cost. (authors)

  16. Why Do Athletes Drink Sports Drinks? A Learning Cycle to Explore the Concept of Osmosis

    ERIC Educational Resources Information Center

    Carlsen, Brook; Marek, Edmund A.

    2010-01-01

    Why does an athlete reach for a sports drink after a tough game or practice? The learning cycle presented in this article helps students answer this question. Learning cycles (Marek 2009) are designed to guide students through direct experiences with a particular concept. In this article, students learn about "osmosis," or the moving of water into…

  17. Changing Pre-School Children's Conceptions of the Day/Night Cycle.

    ERIC Educational Resources Information Center

    Valanides, N.; Gritsi, F.; Kampeza, M.; Ravanis, K.

    2000-01-01

    Examined the impact of a teaching intervention on preschoolers' concepts of the day/night cycle. Found that most children readily accepted that the sun and earth are separate spherical objects, but fewer attributed the day/night cycle to rotation of the earth on its axis. Most were puzzled by simultaneous movements of the earth around the sun and…

  18. Historical constraints on the origins of the carbon cycle concept

    NASA Astrophysics Data System (ADS)

    Galvez, Matthieu Emmanuel; Gaillardet, Jérôme

    2012-11-01

    Understanding the geological carbon cycle remains a major scientific challenge, although studies dedicated to this issue, in particular those of J.J. Ebelmen in the mid 19th century, have existed for over 200 years. The exact scientific and social pathways leading to the construction of the contemporaneous carbon cycle requires further investigation, which in turn may provide valuable insights into the modern state of scientific knowledge. The present study contributes to this question by demonstrating that, following the discovery of the compound nature of carbonic acid by A.L. Lavoisier at the end of the 18th century, studies initially investigated the mechanisms of respiration and photosynthesis until they were recognized as exerting an antagonistic effect on the composition of air. In the early 19th century, the consequence of these studies at the global scale had been foreseen, and applied to investigate the stability of the atmospheric composition over time. These early steps were only concerned with the fate of carbonic acid through life processes. However, between 1820 and 1840, the works of A.L. Brongniard and J.B. Boussingault established that geologic processes, such as the burial of carbonaceous material (CM) in sedimentary rocks and the release of CO2 by volcanoes, affect the composition of the atmosphere. By 1845, J.J. Ebelmen had brilliantly contributed to the emerging question of atmospheric composition by proposing that the alteration of silicates on continents and the precipitation of carbonates in the ocean should be considered as a sink of atmospheric CO2. He also used chemical formula of the time to quantify this process, which led him to mention a carbon rotation for the first time. The rotation of this element through geologic processes became, in itself, a matter worthy of investigation as was the composition of the atmosphere. We argue that J.J. Ebelmen's brilliant synthesis was made possible by the parallel development of the atomistic

  19. The UMR Conception Cycle of Vocational School Students in Solving Linear Equation

    ERIC Educational Resources Information Center

    Li, Shao-Ying; Leon, Shian

    2013-01-01

    The authors designed instruments from theories and literatures. Data were collected throughout remedial teaching processes and interviewed with vocational school students. By SOLO (structure of the observed learning outcome) taxonomy, the authors made the UMR (unistructural-multistructural-relational sequence) conception cycle of the formative and…

  20. Advanced fusion MHD power conversion using the CFAR (compact fusion advanced Rankine) cycle concept

    SciTech Connect

    Hoffman, M.A.; Campbell, R.; Logan, B.G.; Lawrence Livermore National Lab., CA )

    1988-10-01

    The CFAR (compact fusion advanced Rankine) cycle concept for a tokamak reactor involves the use of a high-temperature Rankine cycle in combination with microwave superheaters and nonequilibrium MHD disk generators to obtain a compact, low-capital-cost power conversion system which fits almost entirely within the reactor vault. The significant savings in the balance-of-plant costs are expected to result in much lower costs of electricity than previous concepts. This paper describes the unique features of the CFAR cycle and a high- temperature blanket designed to take advantage of it as well as the predicted performance of the MHD disk generators using mercury seeded with cesium. 40 refs., 8 figs., 3 tabs.

  1. Impact du réchauffement climatique sur le cycle hydrologique

    NASA Astrophysics Data System (ADS)

    Planton, Serge; Déqué, Michel; Douville, Hervé; Spagnoli, Bruno

    2005-02-01

    At the planetary scale, the models consistently simulate an intensification of the hydrological cycle in a future climate, warmer than the present-day one. However, this intensification might be accompanied by its slowing down due to an increase of the residence time of water vapour in the atmosphere. The impact of climate change on extreme events is even more difficult to evaluate, as results are dependent on methods, emission scenarios and, above all, on models. However, the increase of extreme winter precipitation over northern Europe is a common feature of these evaluations. The hydrological cycle, through the geographical distribution of continental surface humidity, seems to play a key role on the possibility to detect the warming in France. To cite this article: S. Planton et al., C. R. Geoscience 337 (2005).

  2. A metallic fuel cycle concept from spent oxide fuel to metallic fuel

    SciTech Connect

    Fujita, Reiko; Kawashima, Masatoshi; Yamaoka, Mitsuaki; Arie, Kazuo; Koyama, Tadafumi

    2007-07-01

    A Metallic fuel cycle concept for Self-Consistent Nuclear Energy System (SCNES) has been proposed in a companion papers. The ultimate goal of the SCNES is to realize sustainable energy supply without endangering the environment and humans. For future transition period from LWR era to SCNES era, a new metallic fuel recycle concept from LWR spent fuel has been proposed in this paper. Combining the technology for electro-reduction of oxide fuels and zirconium recovery by electrorefining in molten salts in the nuclear recycling schemes, the amount of radioactive waste reduced in a proposed metallic fuel cycle concept. If the recovery ratio of zirconium metal from the spent zirconium waste is 95%, the cost estimation in zirconium recycle to the metallic fuel materials has been estimated to be less than 1/25. (authors)

  3. Analysis of a New Rocket-Based Combined-Cycle Engine Concept at Low Speed

    NASA Technical Reports Server (NTRS)

    Yungster, S.; Trefny, C. J.

    1999-01-01

    An analysis of the Independent Ramjet Stream (IRS) cycle is presented. The IRS cycle is a variation of the conventional ejector-Ramjet, and is used at low speed in a rocket-based combined-cycle (RBCC) propulsion system. In this new cycle, complete mixing between the rocket and ramjet streams is not required, and a single rocket chamber can be used without a long mixing duct. Furthermore, this concept allows flexibility in controlling the thermal choke process. The resulting propulsion system is intended to be simpler, more robust, and lighter than an ejector-ramjet. The performance characteristics of the IRS cycle are analyzed for a new single-stage-to-orbit (SSTO) launch vehicle concept, known as "Trailblazer." The study is based on a quasi-one-dimensional model of the rocket and air streams at speeds ranging from lift-off to Mach 3. The numerical formulation is described in detail. A performance comparison between the IRS and ejector-ramjet cycles is also presented.

  4. La silice et le cycle du carbone dans l'océan

    NASA Astrophysics Data System (ADS)

    Tréguer, Paul

    2002-01-01

    Silicon is a key element whose major role in the control of the cycle of carbon in the ocean has been recently revealed. This is first illustrated through the resolution of the 'opal paradox' in the modern Southern Ocean. Second, the 'silica hypothesis' explains why, during the Last Glacial Maximum, the atmospheric concentration of CO 2 was about 40 % below that of the interglacial period. Increased deliveries of wind-borne silica to the surface ocean as well as of riverine inputs favoured the dominance of diatoms over coccolithophorids, resulting in a net emission decrease of CO 2 by coccolithophorids from the ocean surface to the atmosphere. To cite this article: P. Tréguer, C. R. Geoscience 334 (2002) 3-11

  5. Concept for a small, colocated fuel cycle facility for oxide breeder fuels

    SciTech Connect

    Burch, W.D.; Lerch, R.E.; Stradley, J.G.

    1987-01-01

    As part of a United States Department of Energy (USDOE) program to examine innovative liquid-metal reactor (LMR) system designs over the past three years, the Oak Ridge National Laboratory (ORNL) and the Westinghouse Hanford Company (WHC) collaborated on studies of mixed oxide fuel cycle options. A principal effort was an advanced concept for a small integrated fuel cycle colocated with a 1300-MW(e) reactor station. The study provided a scoping design, capital and operating cost estimates, and a basis on which to proceed with implementation of such a facility if future plans so dictate. The facility integrated reprocessing, waste management, and refabrication functions in a single facility of nominal 35-t/year capacity utilizing the latest technology developed in fabrication programs at WHC and in reprocessing at ORNL. The concept was based on many years of work at both sites and extensive design studies of prior years.

  6. Concept for a small, colocated fuel cycle facility for oxide breeder fuels

    SciTech Connect

    Burch, W.D.; Stradley, J.G.; Lerch, R.E.

    1987-01-01

    As part of a United States Department of Energy (USDOE) program to examine innovative liquid-metal reactor (LMR) system designs over the past three years, the Oak Ridge National Laboratory (ORNL) and the Westinghouse Hanford Company (WHC) collaborated on studies of mixed oxide fuel cycle options. A principal effort was an advanced concept for a small integrated fuel cycle colocated with a 1300-MW(e) reactor station. The study provided a scoping design and a basis on which to proceed with implementation of such a facility if future plans so dictate. The facility integrated reprocessing, waste management, and refabrication functions in a single facility of nominal 35-t/year capacity utilizing the latest technology developed in fabrication programs at WHC and in reprocessing at ORNL. The concept was based on many years of work at both sites and extensive design studies of prior years.

  7. The concept of specificity and the Italian contribution to the discovery of the malaria transmission cycle.

    PubMed

    Fantini, B

    1999-09-01

    At the dawn of the 20th century, the change in the scientific, political and cultural attitudes towards malaria was the result of the discovery of the theoretical simplicity of the malaria transmission cycle and of the possibility to interrupt it, by avoiding the contacts between people and mosquitoes. The 'mosquito hypothesis', suggested already in the 1880s, had to be included into a coherent scientific theory, in which a fundamental part was played by the concept of specificity. The paper analyses the Italian contribution to this scientific change and the epistemological aspects of the debate between Ronald Ross and Battista Grassi about their respective role in the discovery of the human malaria transmission cycle. This debate has been often interpreted in sociological or psychological terms. However, behind the dispute there is a different definition of what is a scientific explanation in biological sciences and in particular in parasitology. This point is made clear by the analysis of four different theoretical problems implied in the discovery of the transmission cycle: the concept of specificity, the comparative method in parasitology, the specificity of the life-cycle of parasites and vectors, and the role of the analogical reasoning in science and medicine. PMID:10697832

  8. Development and proof-testing of advanced absorption refrigeration cycle concepts

    SciTech Connect

    Modahl, R.J.; Hayes, F.C. . Applied Unitary/Refrigeration Systems Div.)

    1992-03-01

    The overall objectives of this project are to evaluate, develop, and proof-test advanced absorption refrigeration cycles that are applicable to residential and commercial heat pumps for space conditioning. The heat pump system is to be direct-fired with natural gas and is to use absorption working fluids whose properties are known. Target coefficients of performance (COPs) are 1.6 at 47{degrees}F and 1.2 at 17{degrees} in the heating mode, and 0.7 at 95{degree}F in the cooling mode, including the effect of flue losses. The project is divided into three phases. Phase I entailed the analytical evaluation of advanced cycles and included the selection of preferred concepts for further development. Phase II involves the development and testing of critical components and of a complete laboratory breadboard version of the selected system. Phase III calls for the development of a prototype unit and is contingent on the successful completion of Phase II. This report covers Phase I work on the project. In Phase 1, 24 advanced absorption cycle/fluid combinations were evaluated, and computer models were developed to predict system performance. COP, theoretical pump power, and internal heat exchange were calculated for each system, and these calculations were used as indicators of operating and installed costs in order to rank the relative promise of each system. The highest ranking systems involve the cycle concept of absorber/generator heat exchange, generator heat exchanger/absorber heat exchange, regeneration, and resorption/desorption, in combination with the NH{sub 3}/H{sub 2}O/LiBr ternary absorption fluid mixture or with the NH{sub 3}/H{sub 2}O binary solution. Based upon these conclusions, the recommendation was made to proceed to Phase II, the laboratory breadboard proof-of- concept.

  9. Review of open-cycle desiccant air-conditioning concepts and systems

    SciTech Connect

    Wurm, J.

    1986-08-01

    This paper attempts to overview the development status of desiccant cooling. Over the past 30 years of progressively intensifying attention, this promising technology has become a domain of interest of many research agencies and manufacturing companies. As a result, the market potential for machines based on desiccant processes, particularly in comfort cooling and agricultural applications, is getting close to realization. One of the most important incentives of developing heat-activated, open-cycle desiccant cooling machines (air conditioners) has always been its potential simplicity. Such premise has been deceiving to a degree that in many instances has slowed the progress. However, the persistent analytical and material research brought some desiccant systems close to the marketplace. They provide attractive alternatives to consumers and utilities, offering particularly effective humidity and temperature control in cases of high fresh-air-makeup requirements. The control of bacteria, airborne particulates, as well as CO/sub 2/, combined with effective heating capability make them attractive for controlled-atmosphere agriculture. Finally, the capability of using low-temperature waste heat to drive the cycle becomes an important attribute of a desiccant concept, specifically when combined with a regular vapor-compression cooling machine in energy saving space-conditioning concepts. The presented assessment concludes that, particularly for specialized applications, machines based on open-cycle desiccant cooling processes are very close to playing an important role in the space-conditioning (including comfort control) marketplace.

  10. The concept of the sexual reproduction cycle and its evolutionary significance

    PubMed Central

    Bai, Shu-Nong

    2015-01-01

    The concept of a “sexual reproduction cycle (SRC)” was first proposed by Bai and Xu (2013) to describe the integration of meiosis, sex differentiation, and fertilization. This review discusses the evolutionary and scientific implications of considering these three events as part of a single process. Viewed in this way, the SRC is revealed to be a mechanism for efficiently increasing genetic variation, facilitating adaptation to environmental challenges. It also becomes clear that, in terms of cell proliferation, it is appropriate to contrast mitosis with the entire SRC, rather than with meiosis alone. Evolutionarily, it appears that the SRC was first established in unicellular eukaryotes and that all multicellular organisms evolved within that framework. This concept provides a new perspective into how sexual reproduction evolved, how generations should be defined, and how developmental processes of various multicellular organisms should properly be compared. PMID:25667590

  11. Executive Summary of Ares V: Lunar Capabilities Concept Review Through Phase A-Cycle 3

    NASA Technical Reports Server (NTRS)

    Holladay, J. B.; Baggett, K. E.; Feldman, S. M.

    2011-01-01

    This Technical Memorandum (TM) was generated as an overall Ares V summary from the Lunar Capabilities Concept Review (LCCR) through Phase A-Cycle 3 (PA-C3) with the intent that it may be coupled with separately published appendices for a more detailed, integrated narrative. The Ares V has evolved from the initial point of departure (POD) 51.00.48 LCCR configuration to the current candidate POD, PA-C3D, and the family of vehicles concept that contains vehicles PA-C3A through H. The logical progression from concept to POD vehicles is summarized in this TM and captures the trade space and performance of each. The family-of-vehicles concept was assessed during PA-C3 and offered flexibility in the path forward with the ability to add options deemed appropriate. A description of each trade space is given in addition to a summary of each Ares V element. The Ares V contributions to a Mars campaign are also highlighted with the goal of introducing Ares V capabilities within the trade space. The assessment of the Ares V vehicle as it pertains to Mars missions remained locked to the architecture presented in Mars Design Reference Authorization 5.0 using the PA-C3D vehicle configuration to assess Mars transfer vehicle options, in-space EDS capabilities, docking adaptor and propellant transfer assessments, and lunar and Mars synergistic potential.

  12. L'Apprentissage et le Changement des Attitudes envers Soi-meme: Le Concept de Soi. (Learning and the Change of Attitudes Towards Oneself: Self Image).

    ERIC Educational Resources Information Center

    Leduc, Aimee

    1980-01-01

    The French language article is the second in a series and describes the principles of classic conditioning which underlie attitude formation and change. The article also notes the many functions of self-concept attitudes in order to guide the choices of intervention in attitude learning. (Author/SB)

  13. Effectiveness of 5E Learning Cycle Instruction on Students' Achievement in Cell Concept and Scientific Epistemological Beliefs

    ERIC Educational Resources Information Center

    Kaynar, Devrim; Tekkaya, Ceren; Cakiroglu, Jale

    2009-01-01

    This study investigated the effectiveness of 5E learning cycle on 6th-grade students' achievement of cell concepts, and their scientific epistemological beliefs. Epistemological Belief Questionnaire and the Cell Concept Test were administered as pre-test and post-test to a total of 153 sixth grade students in four intact classes of an elementary…

  14. Water Transformation and Storage in the Mountains and at the Coast: Midwest Students' Disconnected Conceptions of the Hydrologic Cycle

    ERIC Educational Resources Information Center

    Shepardson, Daniel P.; Wee, Bryan; Priddy, Michelle; Schellenberger, Lauren; Harbor, Jon

    2009-01-01

    The purpose of the present study was to investigate students' conceptions of the hydrologic cycle and to examine whether these conceptions vary by grade level and community setting. This study was descriptive in nature and reflected a cross-age design involving the collection of qualitative data from 1,298 students from the Midwest, USA. These…

  15. Inhibition of progesterone secretion by oestradiol administered in the luteal phase of assisted conception cycles.

    PubMed

    Tay, P Y; Lenton, E A

    2003-06-01

    A prospective randomised study was done to assess the effect of supplemental oestradiol in addition to progesterone on the luteal steroid profiles and pregnancy outcome in stimulated cycles with and without pituitary down regulation. Women undergoing stimulated cycle IVF with GnRH-a and FSH (Group A, n = 63) or stimulated intrauterine insemination using CC and FSH (Group B, n = 55) were studied. These subjects were randomly allocated to receive either 400 mg daily of vaginally administrated Cyclogest (progesterone) alone or in combination with 2 mg daily of oral Oestradiol Valerate (E2V) during the luteal phase. Significant lower concentrations of plasma progesterone were observed in those subjects supplemented with both E2V and progesterone compared to those in whom progesterone only was given during the luteal phase (P < 0.05). Exogenous E2V had a minimal impact on plasma oestradiol concentrations and did not disguise the characterised mid luteal decline in oestradiol secretion. The suppressive effect of E2V on plasma progesterone was lost if implantation occurred normally because any small change in steroid concentrations was reversed by the rapidly increasing concentrations of HCG. Similar pregnancy rates were observed among subjects supplemented with or without oestradiol. The addition of oestradiol to the luteal supplement suppresses endogenous corpus luteum progesterone secretion irrespective of the type of assisted conception cycle and that its use is unlikely to be beneficial to the process of implantation. PMID:14569738

  16. Technology Concept for a Near-Term Closed Brayton Cycle Power Conversion Unit

    NASA Astrophysics Data System (ADS)

    Foti, John; Halsey, Dave; Bauch, Tim; Smith, Glen

    2003-01-01

    There is a need in the space science community for nuclear-powered electric propulsion systems to enable high-value, deep space and planetary exploration. Certain missions are driven by once-in-a-lifetime or highly infrequent occurrences that require the near-term development of a flight-capable nuclear space power and electric propulsion system in order to take advantage of the scientific opportunity. The broader applicability of Brayton power systems to the commercial and military aircraft markets has provided fertile ground for the continued development and implementation of new technologies applicable to a closed Brayton cycle space Power Conversion Unit (PCU). One concept for effectively achieving a near-term Brayton space power capability is based on the development work associated with the Integrated Power Unit (IPU). This unit embodies the state of the art in turbomachinery, generators, bearing systems and electric power management and distribution capability that can readily be evolved into a closed Brayton cycle PCU. This paper provides an overview of aircraft-based Brayton power system technologies, their implementation into the IPU and one approach for leveraging this capability into a near-term closed Brayton cycle space power conversion unit.

  17. Thermodynamic analysis of a new conception of supplementary firing in a combined cycle

    NASA Astrophysics Data System (ADS)

    Kotowicz, Janusz; Bartela, Łukasz; Balicki, Adrian

    2010-10-01

    The paper analyzes a new concept of integration of combined cycle with the installation of supplementary firing. The whole system was enclosed by thermodynamic analysis, which consists of a gas-steam unit with triple-pressure heat recovery steam generator. The system uses a determined model of the gas turbine and the assumptions relating to the construction features of steam-water part were made. The proposed conception involves building of supplementary firing installation only on part of the exhaust stream leaving the gas turbine. In the proposed solution superheater was divided into two sections, one of which was located on the exhaust gases leaving the installation of supplementary firing. The paper presents the results of the analyses of which the main aim was to demonstrate the superiority of the new thermodynamic concept of the supplementary firing over the classical one. For this purpose a model of a system was built, in which it was possible to carry out simulations of the gradual transition from a classically understood supplementary firing to the supplementary firing completely modified. For building of a model the GateCycle™ software was used.

  18. Generic Repository Concepts and Thermal Analysis for Advanced Fuel Cycles - 12477

    SciTech Connect

    Hardin, Ernest; Blink, James; Carter, Joe; Fratoni, Massimiliano; Greenberg, Harris; Sutton, Mark; Howard, Robert

    2012-07-01

    A geologic disposal concept for spent nuclear fuel (SNF) or high-level waste (HLW) consists of three components: waste inventory, geologic setting, and concept of operations. A set of reference geologic disposal concepts has been developed by the U.S. Department of Energy (DOE), Used Fuel Disposition campaign. Reference concepts are identified for crystalline rock, clay/shale, bedded salt, and deep borehole (crystalline basement) geologic settings. These were analyzed for waste inventory cases representing a range of waste types that could be produced by advanced nuclear fuel cycles. Concepts of operation consisting of emplacement mode, repository layout, and engineered barrier descriptions, were selected based on international progress. All of these disposal concepts are enclosed emplacement modes, whereby waste packages are in direct contact with encapsulating engineered or natural materials. Enclosed modes have less capacity to dissipate heat than open modes such as that proposed for a repository at Yucca Mountain. Thermal analysis has identified important relationships between waste package size and capacity, and the duration of surface decay storage needed to meet temperature limits for different disposal concepts. For the crystalline rock and clay/shale repository concepts, a waste package surface temperature limit of 100 deg. C was assumed to prevent changes in clay-based buffer material or clay-rich host rock. Surface decay storage of 50 to 100 years is needed for disposal of high-burnup LWR SNF in 4-PWR packages, or disposal of HLW glass from reprocessing LWR uranium oxide (UOX) fuel. High-level waste (HLW) from reprocessing of metal fuel used in a fast reactor could be disposed after decay storage of 50 years or less. For disposal in salt the rock thermal conductivity is significantly greater, and higher temperatures (200 deg. C) can be tolerated at the waste package surface. Decay storage of 10 years or less is needed for high-burnup LWR SNF in 4-PWR

  19. Influence des melanges complexes organiques sur le sort des dioxines et furanes: Implications dans le developpement de facteurs de caracterisation en analyse du cycle de vie

    NASA Astrophysics Data System (ADS)

    Taing, Eric

    The environmental fate of dioxins and furans, or polychlorodibenzo-p-dioxins and -furans (PCDD/Fs), leaching from wood poles treated with pentachlorophenol (PCP) oil is modified by the presence of oil. Interactions between co-contaminants, which also exist for other pollutants within the mixtures, were shown in the specific context of risk analysis, but have never been taken into account for the generic context of life cycle assessment (LCA). This decision-making tool relies on characterization factors (CF) to estimate the potential impacts of an emitted amount of a pollutant in different impact categories such as aquatic ecotoxicity and human toxicity. For these two impact categories, CFs are calculated from a cause-effect chain that models the environmental fate, exposure and effects of the pollutant (represented by a matrix of fate FF, exposure XF and effect EF, respectively), meaning that a modification of PCDD/Fs fate induces a change in PCDD/Fs CFs. The research question is therefore as follows: In life cycle impact assessment (LCIA), to what extent would the potential impacts of PCDD/Fs on aquatic ecotoxicity and human toxicity change when taking into account the influence of a complex organic mixture on PCDD/Fs fate?. Thus, the main objective is to develop CFs of PCDD/Fs when their fate is influenced by PCP oil and compare them with the CFs of PCDD/Fs without oil for the aquatic ecotoxicity and human toxicity impact categories. A mathematic approach is established to determine the new environmental distribution of PCDD/Fs in the presence of oil and a new FF' matrix is calculated from this new distribution to obtain new CFs' integrating oil influence. FF' and CF' are then compared to FF and CF of PCDD/Fs without the oil. Finally, potential (eco)toxic impacts of the PCDD/F Canadian emissions are calculated with the new CFs' of PCDD/Fs in presence of oil. By only focusing on the results for an emission into air, freshwater and natural soil on a continental

  20. A novel concept of QUADRISO particles Part III : applications to the plutonium-thorium fuel cycle.

    SciTech Connect

    Talamo, A.

    2009-03-01

    In the present study, a plutonium-thorium fuel cycle is investigated including the {sup 233}U production and utilization. A prismatic thermal High Temperature Gas Reactor (HTGR) and the novel concept of quadruple isotropic (QUADRISO) coated particles, designed at the Argonne National Laboratory, have been used for the study. In absorbing QUADRISO particles, a burnable poison layer surrounds the central fuel kernel to flatten the reactivity curve as a function of time. At the beginning of life, the fuel in the QUADRISO particles is hidden from neutrons, since they get absorbed in the burnable poison before they reach the fuel kernel. Only when the burnable poison depletes, neutrons start streaming into the fuel kernel inducing fission reactions and compensating the fuel depletion of ordinary TRISO particles. In fertile QUADRISO particles, the absorber layer is replaced by natural thorium with the purpose of flattening the excess of reactivity by the thorium resonances and producing {sup 233}U. The above configuration has been compared with a configuration where fissile (neptunium-plutonium oxide from Light Water Reactors irradiated fuel) and fertile (natural thorium oxide) fuels are homogeneously mixed in the kernel of ordinary TRISO particles. For the {sup 233}U utilization, the core has been equipped with europium oxide absorbing QUADRISO particles.

  1. The concept of vulnerability within the disaster management cycle - A geospatial perspective

    NASA Astrophysics Data System (ADS)

    Aubrecht, Christoph; Freire, Sérgio; Kienberger, Stefan; Steinnocher, Klaus; Zeil, Peter

    2010-05-01

    This paper illustrates the concept of vulnerability within the disaster management cycle from a geospatial perspective. Disaster management is widely regarded as a cyclic multi-stage concept starting with (1) a response phase after a disaster strikes, followed by (2) risk analysis and (3) mitigation efforts to minimize the impacts of future disasters. Different types of hazards such as hurricanes, tsunamis, floods, earthquakes and fires feature individual characteristics and require adapted actions in all three stages mentioned above. From a general point of view the phase of response includes first-pass impact assessment and accordingly coordinated search and rescue efforts as well as follow-on recovery and rehabilitation. Mitigating impacts of disasters starts with risk reduction and prevention measurements whereas land use management plays an important role as well as general preparedness both in terms of social and economic activities and infrastructural measures. Prediction and early warning preceding the next hazard event form the final part of this phase and at the same time start the next run of the disaster management cycle. Risk assessment as an integral part of disaster management is composed of hazard and vulnerability analysis. Most aspects of hazard investigations have a spatial component whereas both Earth Observation data and terrestrial surveys provide essential information for delineation of potentially affected areas and monitoring influencing environmental conditions. The mere incidence of a natural event does not necessarily cause negative effects, e.g. wildfires are actually an important factor for ecosystem stability and recurring flooding often benefits riparian forests and agricultural areas. The term disaster is thus not used until impacts on social systems including human beings and associated assets (i.e. economic, infrastructural) are caused. This is where the concept of vulnerability comes into play which is defined by a set of

  2. Digital Avionics Information System (DAIS): Impact of DAIS Concept on Life Cycle Cost--Supplement. Final Report.

    ERIC Educational Resources Information Center

    Goclowski, John C.; And Others

    This supplement to a technical report providing the results of a preliminary investigation of the potential impact of the Digital Avionics Information System (DAIS) concept on system support personnel requirements and life cycle cost (LCC) includes: (1) additional details of the cost comparison of a hypothetical application of a conceptual…

  3. Effect of the Four-Step Learning Cycle Model on Students' Understanding of Concepts Related to Simple Harmonic Motion

    ERIC Educational Resources Information Center

    Madu, B. C.

    2012-01-01

    The study explored the efficacy of four-step (4-E) learning cycle approach on students understanding of concepts related to Simple Harmonic Motion (SHM). 124 students (63 for experimental group and 61 for control group) participated in the study. The students' views and ideas in simple Harmonic Achievement test were analyzed qualitatively. The…

  4. Facilitating Conceptual Change in Understanding State of Matter and Solubility Concepts by Using 5E Learning Cycle Model

    ERIC Educational Resources Information Center

    Ceylan, Eren; Geban, Omer

    2009-01-01

    The main purpose of the study was to compare the effectiveness of 5E learning cycle model based instruction and traditionally designed chemistry instruction on 10th grade students' understanding of state of matter and solubility concepts. In this study, 119 tenth grade students from chemistry courses instructed by same teacher from an Anatolian…

  5. Concept definition study of small Brayton cycle engines for dispersed solar electric power systems

    NASA Technical Reports Server (NTRS)

    Six, L. D.; Ashe, T. L.; Dobler, F. X.; Elkins, R. T.

    1980-01-01

    Three first-generation Brayton cycle engine types were studied for solar application: a near-term open cycle (configuration A), a near-term closed cycle (configuration B), and a longer-term open cycle (configuration C). A parametric performance analysis was carried out to select engine designs for the three configurations. The interface requirements for the Brayton cycle engine/generator and solar receivers were determined. A technology assessment was then carried out to define production costs, durability, and growth potential for the selected engine types.

  6. Representing and constructing liquefaction cycle alternatives for FLNG FEED using system entity structure concepts

    NASA Astrophysics Data System (ADS)

    Ha, Sol; Lee, Kyu-Yeul

    2014-09-01

    To support the procedure for determining an optimal liquefaction cycle for FLNG FEED, an ontological modeling method which can automatically generate various alternative liquefaction cycles were carried out in this paper. General rules in combining equipment are extracted from existing onshore liquefaction cycles like C3MR and DMR cycle. A generic relational model which represents whole relations of the plant elements has all these rules, and it is expressed by using the system entity structure (SES), an ontological framework that hierarchically represents the elements of a system and their relationships. By using a process called pruning which reduces the SES to a candidate, various alternative relational models of the liquefaction cycles can be automatically generated. These alternatives were provided by XML-based formats, and they can be used for choosing an optimal liquefaction cycle on the basis of the assessments such as process simulation and reliability analysis

  7. Is the Rock Cycle an Outdated Idea, or a Unifying Concept?

    ERIC Educational Resources Information Center

    Eves, Robert Leo; Davis, Larry Eugene

    1988-01-01

    Discusses how rock-cycle diagrams can graphically illustrate the interrelationship between materials and processes in physical geology courses. Reviews nine contemporary physical geology textbooks with regard to their use of such diagrams. (TW)

  8. Thermodynamic limits of hydrologic cycling within the Earth system: concepts, estimates and implications

    NASA Astrophysics Data System (ADS)

    Kleidon, A.; Renner, M.

    2013-03-01

    The hydrologic cycle results from the combination of energy conversions and atmospheric transport, and the laws of thermodynamics set limits to both. Here, we apply thermodynamics to derive the limits of the strength of hydrologic cycling within the Earth system and the properties and processes that shape these limits. We set up simple models to derive analytical expressions of the limits of evaporation and precipitation in relation to vertical and horizontal differences in solar radiative forcing. These limits result from a fundamental trade-off by which a greater evaporation rate reduces the temperature gradient and thus the driver for atmospheric motion that exchanges moistened air from the surface with the drier air aloft. The limits on hydrologic cycling thus reflect the strong interaction between the hydrologic flux, motion, and the driving gradient. Despite the simplicity of the models, they yield estimates for the limits of hydrologic cycling that are within the observed magnitude, suggesting that the global hydrologic cycle operates near its maximum strength. We close with a discussion of how thermodynamic limits can provide a better characterization of the interaction of vegetation and human activity with hydrologic cycling.

  9. Thermodynamic limits of hydrologic cycling within the Earth system: concepts, estimates and implications

    NASA Astrophysics Data System (ADS)

    Kleidon, A.; Renner, M.

    2013-07-01

    The hydrologic cycle results from the combination of energy conversions and atmospheric transport, and the laws of thermodynamics set limits to both. Here, we apply thermodynamics to derive the limits of the strength of hydrologic cycling within the Earth system and about the properties and processes that shape these limits. We set up simple models to derive analytical expressions of the limits of evaporation and precipitation in relation to vertical and horizontal differences in solar radiative forcing. These limits result from a fundamental trade-off by which a greater evaporation rate reduces the temperature gradient and thus the driver for atmospheric motion that exchanges moistened air from the surface with the drier air aloft. The limits on hydrologic cycling thus reflect the strong interaction between the hydrologic flux, motion, and the driving gradient. Despite the simplicity of the models, they yield estimates for the limits of hydrologic cycling that are within the observed magnitude, suggesting that the global hydrologic cycle operates near its maximum strength. We close with a discussion of how thermodynamic limits can provide a better characterization of the interaction of vegetation and human activity with hydrologic cycling.

  10. Development and proof-testing of advanced absorption refrigeration cycle concepts. Report on Phases 1 and 1A

    SciTech Connect

    Modahl, R.J.; Hayes, F.C.

    1992-03-01

    The overall objectives of this project are to evaluate, develop, and proof-test advanced absorption refrigeration cycles that are applicable to residential and commercial heat pumps for space conditioning. The heat pump system is to be direct-fired with natural gas and is to use absorption working fluids whose properties are known. Target coefficients of performance (COPs) are 1.6 at 47{degrees}F and 1.2 at 17{degrees} in the heating mode, and 0.7 at 95{degree}F in the cooling mode, including the effect of flue losses. The project is divided into three phases. Phase I entailed the analytical evaluation of advanced cycles and included the selection of preferred concepts for further development. Phase II involves the development and testing of critical components and of a complete laboratory breadboard version of the selected system. Phase III calls for the development of a prototype unit and is contingent on the successful completion of Phase II. This report covers Phase I work on the project. In Phase 1, 24 advanced absorption cycle/fluid combinations were evaluated, and computer models were developed to predict system performance. COP, theoretical pump power, and internal heat exchange were calculated for each system, and these calculations were used as indicators of operating and installed costs in order to rank the relative promise of each system. The highest ranking systems involve the cycle concept of absorber/generator heat exchange, generator heat exchanger/absorber heat exchange, regeneration, and resorption/desorption, in combination with the NH{sub 3}/H{sub 2}O/LiBr ternary absorption fluid mixture or with the NH{sub 3}/H{sub 2}O binary solution. Based upon these conclusions, the recommendation was made to proceed to Phase II, the laboratory breadboard proof-of- concept.

  11. Coculture with endothelial cells reduces the population of cycling LeX neural precursors but increases that of quiescent cells with a side population phenotype

    SciTech Connect

    Mathieu, Celine . E-mail: marc-andre.mouthon@cea.fr

    2006-04-01

    Neural stem cell proliferation and differentiation are regulated by external cues from their microenvironment. As endothelial cells are closely associated with neural stem cell in brain germinal zones, we investigated whether endothelial cells may interfere with neurogenesis. Neural precursor cells (NPC) from telencephalon of EGFP mouse embryos were cocultured in direct contact with endothelial cells. Endothelial cells did not modify the overall proliferation and apoptosis of neural cells, albeit they transiently delayed spontaneous apoptosis. These effects appeared to be specific to endothelial cells since a decrease in proliferation and a raise in apoptosis were observed in cocultures with fibroblasts. Endothelial cells stimulated the differentiation of NPC into astrocytes and into neurons, whereas they reduced differentiation into oligodendrocytes in comparison to adherent cultures on polyornithine. Determination of NPC clonogenicity and quantification of LeX expression, a marker for NPC, showed that endothelial cells decreased the number of cycling NPC. On the other hand, the presence of endothelial cells increased the number of neural cells having 'side population' phenotype, another marker reported on NPC, which we have shown to contain quiescent cells. Thus, we show that endothelial cells may regulate neurogenesis by acting at different level of NPC differentiation, proliferation and quiescence.

  12. Contrôle non destructif par courants de Foucault : expérience et modélisation pour la conception et l'optimisation de capteurs

    NASA Astrophysics Data System (ADS)

    Bonnin, O.; Cahouet, J.; Giordano, P.

    1993-03-01

    more accurate comparison, for example on the crack depth, is difficult because of the uncertainty on the physical properties of the materials. Dans le cadre d'un projet industiel de conception et d'optimisation de capteurs pour la recherche de fissures par courants de Foucault sur les plate-formes de forage, on présente les études menées pour la modélisation du système. La simulation des phénomènes implique à priori une modélisation tridimensionnelle, certes précise, mais difficile et coûteuse. On cherche à en limiter le coût en combinant une modélisation bidimensionnelle en l'absence de défaut, et une modélisation tridimensionnelle locale en présence d'une fissure. Après avoir présenté le projet et l'étude expérimentale qui en découle, on décrit les techniques de modélisation qui ont été employées.

  13. A new concept for high-cycle-life LEO: Rechargeable MnO2-hydrogen

    NASA Technical Reports Server (NTRS)

    Appleby, A. John; Dhar, Y. J.; Murphy, O. J.; Srinivasan, Supramaniam

    1989-01-01

    The nickel-hydrogen secondary battery system is now the one of choice for use in GEO satellites. It offers superior energy density to that of nickel-cadmium, with a lifetime that is at least comparable in terms of both cycle life and overall operating life. While the number of deep cycles required for GEO use is small, LEO satellites with long lifetimes (5 to 10 years) will require secondary battery systems allowing 30,000 to 60,000 useful cycles which are characterized by an approximately 2C charge rate and C average discharge rate. Recent work has shown that birnessite MnO2 doped with bismuth oxide can be cycled at very high rates (6C) over a very large number of cycles (thousands) at depths-of-discharge in the 85 to 90 percent range, based on two electrons, which discharge at the same potential in a flat plateau. The potential is about 0.7 V vs. hydrogen, with a cut-off at 0.6 V. At first sight, this low voltage would seem to be a disadvantage, since the theoretical energy density will be low. However, it permits the use of lightweight materials that are immune from corrosion at the positive. The high utilization and low equivalent weight of the active material, together with the use of teflon-bonded graphite for current collection, result in very light positives, especially when these are compared with those in a derated nickel-hydrogen system. In addition, the weight of the pressure vessel falls somewhat, since the dead volume is lower. Calculations show that a total system will have 2.5 times the Ah capacity of a derated nickel-hydrogen LEO battery, so that the energy density, based on 1.2 V for nickel-hydrogen and 0.7 V for MnO2-hydrogen, will be 45 percent higher for comparable cycling performance.

  14. A new concept for high-cycle-life LEO: Rechargeable MnO2-hydrogen

    NASA Technical Reports Server (NTRS)

    Appleby, A. J.; Dhar, H. P.; Kim, Y. J.; Murphy, O. J.

    1989-01-01

    The nickel-hydrogen secondary battery system, developed in the early 1970s, has become the system of choice for geostationary earth orbit (GEO) applications. However, for low earth orbit (LEO) satellites with long expected lifetimes the nickel positive limits performance. This requires derating of the cell to achieve very long cycle life. A new system, rechargeable MnO2-Hydrogen, which does not require derating, is described here. For LEO applications, it promises to have longer cycle life, high rate capability, a higher effective energy density, and much lower self-discharge behavior than those of the nickel-hydrogen system.

  15. Digital Avionics Information System (DAIS): Impact of DAIS Concept on Life Cycle Cost. Final Report.

    ERIC Educational Resources Information Center

    Goclowski, John C.; And Others

    Designed to identify and quantify the potential impacts of the Digital Avionics Information System (DAIS) on weapon system personnel requirements and life cycle cost (LCC), this study postulated a typical close-air-support (CAS) mission avionics suite to serve as a basis for comparing present day and DAIS configuration specifications. The purpose…

  16. 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…

  17. Effects of climate extremes on the terrestrial carbon cycle: concepts, processes and potential future impacts.

    PubMed

    Frank, Dorothea; Reichstein, Markus; Bahn, Michael; Thonicke, Kirsten; Frank, David; Mahecha, Miguel D; Smith, Pete; van der Velde, Marijn; Vicca, Sara; Babst, Flurin; Beer, Christian; Buchmann, Nina; Canadell, Josep G; Ciais, Philippe; Cramer, Wolfgang; Ibrom, Andreas; Miglietta, Franco; Poulter, Ben; Rammig, Anja; Seneviratne, Sonia I; Walz, Ariane; Wattenbach, Martin; Zavala, Miguel A; Zscheischler, Jakob

    2015-08-01

    Extreme droughts, heat waves, frosts, precipitation, wind storms and other climate extremes may impact the structure, composition and functioning of terrestrial ecosystems, and thus carbon cycling and its feedbacks to the climate system. Yet, the interconnected avenues through which climate extremes drive ecological and physiological processes and alter the carbon balance are poorly understood. Here, we review the literature on carbon cycle relevant responses of ecosystems to extreme climatic events. Given that impacts of climate extremes are considered disturbances, we assume the respective general disturbance-induced mechanisms and processes to also operate in an extreme context. The paucity of well-defined studies currently renders a quantitative meta-analysis impossible, but permits us to develop a deductive framework for identifying the main mechanisms (and coupling thereof) through which climate extremes may act on the carbon cycle. We find that ecosystem responses can exceed the duration of the climate impacts via lagged effects on the carbon cycle. The expected regional impacts of future climate extremes will depend on changes in the probability and severity of their occurrence, on the compound effects and timing of different climate extremes, and on the vulnerability of each land-cover type modulated by management. Although processes and sensitivities differ among biomes, based on expert opinion, we expect forests to exhibit the largest net effect of extremes due to their large carbon pools and fluxes, potentially large indirect and lagged impacts, and long recovery time to regain previous stocks. At the global scale, we presume that droughts have the strongest and most widespread effects on terrestrial carbon cycling. Comparing impacts of climate extremes identified via remote sensing vs. ground-based observational case studies reveals that many regions in the (sub-)tropics are understudied. Hence, regional investigations are needed to allow a global

  18. Effects of climate extremes on the terrestrial carbon cycle: concepts, processes and potential future impacts

    PubMed Central

    Frank, Dorothea; Reichstein, Markus; Bahn, Michael; Thonicke, Kirsten; Frank, David; Mahecha, Miguel D; Smith, Pete; van der Velde, Marijn; Vicca, Sara; Babst, Flurin; Beer, Christian; Buchmann, Nina; Canadell, Josep G; Ciais, Philippe; Cramer, Wolfgang; Ibrom, Andreas; Miglietta, Franco; Poulter, Ben; Rammig, Anja; Seneviratne, Sonia I; Walz, Ariane; Wattenbach, Martin; Zavala, Miguel A; Zscheischler, Jakob

    2015-01-01

    Extreme droughts, heat waves, frosts, precipitation, wind storms and other climate extremes may impact the structure, composition and functioning of terrestrial ecosystems, and thus carbon cycling and its feedbacks to the climate system. Yet, the interconnected avenues through which climate extremes drive ecological and physiological processes and alter the carbon balance are poorly understood. Here, we review the literature on carbon cycle relevant responses of ecosystems to extreme climatic events. Given that impacts of climate extremes are considered disturbances, we assume the respective general disturbance-induced mechanisms and processes to also operate in an extreme context. The paucity of well-defined studies currently renders a quantitative meta-analysis impossible, but permits us to develop a deductive framework for identifying the main mechanisms (and coupling thereof) through which climate extremes may act on the carbon cycle. We find that ecosystem responses can exceed the duration of the climate impacts via lagged effects on the carbon cycle. The expected regional impacts of future climate extremes will depend on changes in the probability and severity of their occurrence, on the compound effects and timing of different climate extremes, and on the vulnerability of each land-cover type modulated by management. Although processes and sensitivities differ among biomes, based on expert opinion, we expect forests to exhibit the largest net effect of extremes due to their large carbon pools and fluxes, potentially large indirect and lagged impacts, and long recovery time to regain previous stocks. At the global scale, we presume that droughts have the strongest and most widespread effects on terrestrial carbon cycling. Comparing impacts of climate extremes identified via remote sensing vs. ground-based observational case studies reveals that many regions in the (sub-)tropics are understudied. Hence, regional investigations are needed to allow a global

  19. Concept of an innovative water management system with decentralized water reclamation and cascading material-cycle for agricultural areas.

    PubMed

    Fujiwara, T

    2012-01-01

    Unlike in urban areas where intensive water reclamation systems are available, development of decentralized technologies and systems is required for water use to be sustainable in agricultural areas. To overcome various water quality issues in those areas, a research project entitled 'Development of an innovative water management system with decentralized water reclamation and cascading material-cycle for agricultural areas under the consideration of climate change' was launched in 2009. This paper introduces the concept of this research and provides detailed information on each of its research areas: (1) development of a diffuse agricultural pollution control technology using catch crops; (2) development of a decentralized differentiable treatment system for livestock and human excreta; and (3) development of a cascading material-cycle system for water pollution control and value-added production. The author also emphasizes that the innovative water management system for agricultural areas should incorporate a strategy for the voluntary collection of bio-resources. PMID:22828292

  20. Evaluating new processes and concepts for energy and resource recovery from municipal wastewater with life cycle assessment.

    PubMed

    Remy, C; Boulestreau, M; Warneke, J; Jossa, P; Kabbe, C; Lesjean, B

    2016-01-01

    Energy and resource recovery from municipal wastewater is a pre-requisite for an efficient and sustainable water management in cities of the future. However, a sound evaluation of available processes and pathways is required to identify opportunities and short-comings of the different options and reveal synergies and potentials for optimization. For evaluating environmental impacts in a holistic view, the tool of life cycle assessment (LCA, ISO 14040/44) is suitable to characterize and quantify the direct and indirect effects of new processes and concepts. This paper gives an overview of four new processes and concepts for upgrading existing wastewater treatment plants towards energy positive and resource efficient wastewater treatment, based upon an evaluation of their environmental impacts with LCA using data from pilot and full-scale assessments of the considered processes. PMID:26942529

  1. Initial concepts on energetics and mass releases during nonnuclear explosive events in fuel cycle facilities

    SciTech Connect

    Halverson, M.A.; Mishima, J.

    1986-09-01

    Non-nuclear explosions are one of the initiating events (accidents) considered in the US Nuclear Regulatory Commission study of formal methods for estimating the airborne release of radionuclides from fuel cycle facilities. Methods currently available to estimate the energetics and mass airborne release from the four types of non-nuclear explosive events (fast and slow physical explosions and fast and slow chemical explosions) are reviewed. The likelihood that fast physical explosions will occur in fuel cycle facilities appears to be remote and this type of explosion is not considered. Methods to estimate the consequences of slow physical and fast chemical explosions are available. Methods to estimate the consequences of slow chemical explosions are less well defined.

  2. Assessment of Possible Cycle Lengths for Fully Encapsulated Microstructure fueled light water reactor Concepts

    SciTech Connect

    R. Sonat Sen; Michael A. Pope; Abderrafi M. Ougouag; Kemal O. Pasamehmetoglu

    2013-02-01

    The use of TRISO-particle-based dispersion fuel within SiC matrix and cladding materials has the potential to allow the design of extremely safe LWRs with failure-proof fuel. This paper examines the feasibility of LWR-like cycle length for such fuel with the imposed constraint of strictly retaining the original geometry of the fuel pins and assemblies. The motivation for retaining the original geometry is to provide the ability to incorporate the fuel “as-is” into existing LWRs while retaining their thermal–hydraulic characteristics. Another mandatory constraint is use of low enriched uranium (at or below 20 w/o). The feasibility of using this fuel is assessed by looking at two factors: cycle lengths and fuel material failure rates. Other considerations (e.g., safety parameters such as reactivity coefficients, feedback, etc.) were not considered at this stage of the study. The study includes the examination of increases in the TRISO kernel sizes without changing the thickness of any of the coating layers. In addition, cases where the buffer layer thickness is allowed to vary are also considered. The study shows that a naïve use of UO2 (even up to 20 w/o enrichment) results in cycle lengths too short to be practical for existing LWR designs and operational demands. Increasing fissile inventory within the fuel compacts shows that acceptable cycle lengths can be achieved. The increase of fissile inventory can be accomplished through multiple means, including higher particle packing fraction, higher enrichment, larger fuel kernel sizes, and the use of higher density fuels (that contain a higher number of U atoms per unit volume). In this study, starting with the recognized highest packing fraction practically achievable (44%), combinations of the other means have been evaluated. The models demonstrate cycle lengths comparable to those of ordinary LWRs. As expected, TRISO particles with extremely large kernels are shown to fail under all considered scenarios. In

  3. Simulations and Measurements for a concept of powering CALICE-AHCAL at a train-cycled accelerator

    NASA Astrophysics Data System (ADS)

    Göttlicher, P.

    2013-01-01

    Improving calorimetry by usage of the particle-flow algorithm requires to record the details of the shower development. Therefore a high granularity analogue readout hadron calorimeter (AHCAL) with small sensors and with electronics handling the enormous amount of channels, ≈ 40 000/m3, is required. Homogeneity is maintained by avoiding cooling tubes in the active volume and only cooling at the service end. For this concept low power consumption per channel, 40 μW, is essential. Future linear e+e-- collider designs, ILC or CLIC, foresee duty cycles for the bunch delivery. At ILC bunch trains of 1 ms duration are followed by long breaks of 200 ms. Power cycling the front end electronics with the train structure can reduce power consumption by a factor 100. However for a full scale CALICE-AHCAL switched currents reach magnitudes of kilo-amperes. This paper describes the design chain from front end PCB's through to external power supplies. By simulations a concept is developed, in which effects of electromagnetic interferences are kept small and localized. The goal is to keep current loops small, to limit the switched current to the region near the switched consumer and to allow only small frequency currents to spread out further into the system. By that analogue performance can be kept high and parasitic couplings to the surrounding metal structures and other sub-detectors will be minimized. Measurements with existing prototypes support the validity of the simulations.

  4. Concepts, performance review, and prospects of table-top, few-cycle optical parametric chirped-pulse amplification

    NASA Astrophysics Data System (ADS)

    Vaupel, Andreas; Bodnar, Nathan; Webb, Benjamin; Shah, Lawrence; Richardson, Martin

    2014-05-01

    More than 20 years after the first presentation of optical parametric chirped-pulse amplification (OPCPA), the technology has matured as a powerful technique to produce high-intensity, few-cycle, and ultrashort laser pulses. The output characteristics of these systems cover a wide range of center wavelengths, pulse energies, and average powers. The current record performance of table-top, few-cycle OPCPA systems are 16 TW peak power and 22 W average power, which show that OPCPA is able to directly compete with Ti:sapphire chirped-pulse amplification-based systems as source for intense optical pulses. Here, we review the concepts of OPCPA and present the current state-of-the art performance level for several systems reported in the literature. To date, the performance of these systems is most generally limited by the employed pump laser. Thus, we present a comprehensive review on the recent progress in high-energy, high-average-power, picosecond laser systems, which provide improved performance relative to OPCPA pump lasers employed to date. From here, the impact of these novel pump lasers on table-top, few-cycle OPCPA is detailed and the prospects for next-generation OPCPA systems are discussed.

  5. Dual Brayton cycle gas turbine pressurized fluidized bed combustion power plant concept

    SciTech Connect

    Yan, X.L.; Lidsky, L.M.

    1998-07-01

    High generating efficiency has compelling economic and environmental benefits for electric power plants. There are particular incentives to develop more efficient and cleaner coal-fired power plants in order to permit use of the world`s most abundant and secure energy source. This paper presents a newly conceived power plant design, the Dual Brayton Cycle Gas Turbine PFBC, that yields 45% net generating efficiency and fires on a wide range of fuels with minimum pollution, of which coal is a particularly intriguing target for its first application. The DBC-GT design allows power plants based on the state-of-the-art PFBC technology to achieve substantially higher generating efficiencies, while simultaneously providing modern gas turbine and related heat exchanger technologies access to the large coal power generation market.

  6. The impact of discovery learning on middle grade students' conceptions of the water cycle

    NASA Astrophysics Data System (ADS)

    Yoder, John D.

    This study examined the use of discovery learning in science and how it affects students' academic performance as well as their self-efficacy in science. It also used a diagnostic tool to identify students' misconceptions about processes in the water cycle and where the misconceptions originated. While the study showed that the treatment group had a statistically significant greater academic gain from the pre-test to the post- test than did the no-treatment comparison group, from a teachers view point the gain would not be enough to benefit a student's performance on high stakes tests. Because the study was able to identify eight common misconceptions, it suggests that the misconceptions that students possess are difficult to uproot even using teaching methods that have been proven successful.

  7. Concepts for Life Cycle Cost Control Required to Achieve Space Transportation Affordability and Sustainability

    NASA Technical Reports Server (NTRS)

    Rhodes, Russel E.; Zapata, Edgar; Levack, Daniel J. H.; Robinson, John W.; Donahue, Benjamin B.

    2009-01-01

    Cost control must be implemented through the establishment of requirements and controlled continually by managing to these requirements. Cost control of the non-recurring side of life cycle cost has traditionally been implemented in both commercial and government programs. The government uses the budget process to implement this control. The commercial approach is to use a similar process of allocating the non-recurring cost to major elements of the program. This type of control generally manages through a work breakdown structure (WBS) by defining the major elements of the program. If the cost control is to be applied across the entire program life cycle cost (LCC), the approach must be addressed very differently. A functional breakdown structure (FBS) is defined and recommended. Use of a FBS provides the visibifity to allow the choice of an integrated solution reducing the cost of providing many different elements of like function. The different functional solutions that drive the hardware logistics, quantity of documentation, operational labor, reliability and maintainability balance, and total integration of the entire system from DDT&E through the life of the program must be fully defined, compared, and final decisions made among these competing solutions. The major drivers of recurring cost have been identified and are presented and discussed. The LCC requirements must be established and flowed down to provide control of LCC. This LCC control will require a structured rigid process similar to the one traditionally used to control weight/performance for space transportation systems throughout the entire program. It has been demonstrated over the last 30 years that without a firm requirement and methodically structured cost control, it is unlikely that affordable and sustainable space transportation system LCC will be achieved.

  8. Highly Variable Cycle Nozzle Concept: Validation of Flow and Noise Predictions

    NASA Technical Reports Server (NTRS)

    Halbig, Michael C.

    2011-01-01

    Results from experimental and numerical studies of highly Variable Cycle (HVC) exhaust model were presented. The model was designed and fabricated under a Supersonics NRA awarded to Rolls-Royce. The model had a lobed mixer for the core stream nozzle, and elliptic fan stream nozzle, and an ejector. Experiments included far-field acoustic array, phased array, and Particle Image Velocimetry (PIV) measurements. Numerical studies included flow simulations using the WIND-US code and far-field acoustic solutions using an acoustic analogy developed by Goldstein (2003) and Leib and Goldstein (2011). Far-field acoustic measurements showed increased noise levels over the round baseline nozzle when using non-static forward flight conditions. Phased array measurements showed noise sources near the ejector doors when tones were produced for small ejector door positions. Ejector door separation identified in the experiments was reproduced in the numerical flow simulations. Acoustic solutions were unable to match levels measured in the peak jet noise direction indicating additional development work is needed to predict noise from highly three-dimensional flows.

  9. Conception et calibration d'un sonoreacteur pour l'oxydation de la cellulose par le systeme TEMPO/NaOCl/NaBr

    NASA Astrophysics Data System (ADS)

    Paquin, Michel

    Avec le contexte economique actuel dans le domaine des pates et papiers au Canada, l'industrie se doit de diversifier ses produits mis en marche. La fermeture de plus de 20 usines depuis 2005, une baisse du PIB de l'industrie de 1,4 milliard CAD entre 1999--2008, une baisse de la demande de 2,4 %, une diminution du prix de la pate de 20,9 % depuis juillet 2009. La delocalisation du secteur vers l'Asie et l'hemisphere sud sont autant de raisons pour laquelle l'industrie se doit d'etre a l'avant plan de nouvelle technologie a base de fibre de bois. Pour augmenter leur rentabilite, l'industrie se doit de diversifier ses produits dans d'autres secteurs que le simple fabricant de papier impression-ecriture. Sa diversification passe par l'elaboration de nouveaux papiers a valeur ajoutee (papier conducteur, papier bioactif, etc.), par l'utilisation de la biomasse forestiere pour la production d'energie, par l'utilisation de la biomasse forestiere pour l'elaboration d'une plateforme de chimie verte, par l'utilisation de la lignine pour le developpement de polymeres et par l'utilisation de la fibre cellulosique pour la fabrication de nanomateriaux. La fabrication de nanofibrille de cellulose peut devenir un des produits qui servira a diversifier la production des usines de pates et papiers. Les nanofibrilles de cellulose possedent des proprietes mecaniques et chimiques exceptionnelles. Les nanofibrilles de cellulose sont fabriquees a partir d'une oxydation selective de la pate kraft de feuillu avec le systeme TEMPO-NaOCl-NaBr. L'oxydation selective de l'alcool primaire en C6 du monomere de glucose sous forme de carboxylates engendre une modification chimique de la cellulose qui accroit l'hydrophilicite des fibrilles. Suite a cette oxydation, nous devons effectuer une desintegration mecanique de la fibre kraft de feuillu oxydee pour separer les fibrilles. Le processus d'oxydation de la fibre par le systeme TEMPO-NaOCl-NaBr et sa defibrillation par la suite engendre une

  10. A Burst Mode, Ultrahigh Temperature UF4 Vapor Core Reactor Rankine Cycle Space Power System Concept

    NASA Technical Reports Server (NTRS)

    Dugan, E. T.; Kahook, S. D.; Diaz, N. J.

    1996-01-01

    Static and dynamic neutronic analyses have been performed on an innovative burst mode (100's of MW output for a few thousand seconds) Ulvahigh Temperature Vapor Core Reactor (UTVR) space nuclear power system. The NVTR employs multiple, neutronically-coupled fissioning cores and operates on a direct, closed Rankine cycle using a disk Magnetohydrodynamic (MHD) generater for energy conversion. The UTVR includes two types of fissioning core regions: (1) the central Ultrahigh Temperature Vapor Core (UTVC) which contains a vapor mixture of highly enriched UF4 fuel and a metal fluoride working fluid and (2) the UF4 boiler column cores located in the BeO moderator/reflector region. The gaseous nature of the fuel the fact that the fuel is circulating, the multiple coupled fissioning cores, and the use of a two phase fissioning fuel lead to unique static and dynamic neutronic characteristics. Static neutronic analysis was conducted using two-dimensional S sub n, transport theory calculations and three-dimensional Monte Carlo transport theory calculations. Circulating-fuel, coupled-core point reactor kinetics equations were used for analyzing the dynamic behavior of the UTVR. In addition to including reactivity feedback phenomena associated with the individual fissioning cores, the effects of core-to-core neutronic and mass flow coupling between the UTVC and the surrounding boiler cores were also included in the dynamic model The dynamic analysis of the UTVR reveals the existence of some very effectlve inherent reactivity feedback effects that are capable of quickly stabilizing this system, within a few seconds, even when large positive reactivity insertions are imposed. If the UTVC vapor fuel density feedback is suppressed, the UTVR is still inherently stable because of the boiler core liquid-fuel volume feedback; in contrast, suppression of the vapor fuel density feedback in 'conventional" gas core cavity reactors causes them to become inherently unstable. Due to the

  11. Assessment of Possible Cycle Lengths for Fully-Ceramic Micro-Encapsulated Fuel-Based Light Water Reactor Concepts

    SciTech Connect

    R. Sonat Sen; Michael A. Pope; Abderrafi M. Ougouag; Kemal O. Pasamehmetoglu

    2012-04-01

    The tri-isotropic (TRISO) fuel developed for High Temperature reactors is known for its extraordinary fission product retention capabilities [1]. Recently, the possibility of extending the use of TRISO particle fuel to Light Water Reactor (LWR) technology, and perhaps other reactor concepts, has received significant attention [2]. The Deep Burn project [3] currently focuses on once-through burning of transuranic fissile and fissionable isotopes (TRU) in LWRs. The fuel form for this purpose is called Fully-Ceramic Micro-encapsulated (FCM) fuel, a concept that borrows the TRISO fuel particle design from high temperature reactor technology, but uses SiC as a matrix material rather than graphite. In addition, FCM fuel may also use a cladding made of a variety of possible material, again including SiC as an admissible choice. The FCM fuel used in the Deep Burn (DB) project showed promising results in terms of fission product retention at high burnup values and during high-temperature transients. In the case of DB applications, the fuel loading within a TRISO particle is constituted entirely of fissile or fissionable isotopes. Consequently, the fuel was shown to be capable of achieving reasonable burnup levels and cycle lengths, especially in the case of mixed cores (with coexisting DB and regular LWR UO2 fuels). In contrast, as shown below, the use of UO2-only FCM fuel in a LWR results in considerably shorter cycle length when compared to current-generation ordinary LWR designs. Indeed, the constraint of limited space availability for heavy metal loading within the TRISO particles of FCM fuel and the constraint of low (i.e., below 20 w/0) 235U enrichment combine to result in shorter cycle lengths compared to ordinary LWRs if typical LWR power densities are also assumed and if typical TRISO particle dimensions and UO2 kernels are specified. The primary focus of this summary is on using TRISO particles with up to 20 w/0 enriched uranium kernels loaded in Pressurized Water

  12. Fostering Third-Grade Students' Use of Scientific Models with the Water Cycle: Elementary teachers' conceptions and practices

    NASA Astrophysics Data System (ADS)

    Vo, Tina; Forbes, Cory T.; Zangori, Laura; Schwarz, Christina V.

    2015-10-01

    Elementary teachers play a crucial role in supporting and scaffolding students' model-based reasoning about natural phenomena, particularly complex systems such as the water cycle. However, little research exists to inform efforts in supporting elementary teachers' learning to foster model-centered, science learning environments. To address this need, we conducted an exploratory multiple-case study using qualitative research methods to investigate six 3rd-grade teachers' pedagogical reasoning and classroom instruction around modeling practices (construct, use, evaluate, and revise) and epistemic considerations of scientific modeling (generality/abstraction, evidence, mechanism, and audience). Study findings show that all teachers emphasized a subset of modeling practices-construction and use-and the epistemic consideration of generality/abstraction. There was observable consistency between teachers' articulated conceptions of scientific modeling and their classroom practices. Results also show a subset of the teachers more strongly emphasized additional epistemic considerations and, as a result, better supported students to use models as sense-making tools as well as representations. These findings provide important evidence for developing elementary teacher supports to scaffold students' engagement in scientific modeling.

  13. HTGR-GT closed-cycle gas turbine: a plant concept with inherent cogeneration (power plus heat production) capability

    SciTech Connect

    McDonald, C.F.

    1980-04-01

    The high-grade sensible heat rejection characteristic of the high-temperature gas-cooled reactor-gas turbine (HTGR-GT) plant is ideally suited to cogeneration. Cogeneration in this nuclear closed-cycle plant could include (1) bottoming Rankine cycle, (2) hot water or process steam production, (3) desalination, and (4) urban and industrial district heating. This paper discusses the HTGR-GT plant thermodynamic cycles, design features, and potential applications for the cogeneration operation modes. This paper concludes that the HTGR-GT plant, which can potentially approach a 50% overall efficiency in a combined cycle mode, can significantly aid national energy goals, particularly resource conservation.

  14. Conception d'un controleur actif pour le retard de la transition de l'ecoulement laminaire au turbulent sur une aile a geometrie du profil variable dans le tunnel a vent

    NASA Astrophysics Data System (ADS)

    Popov, Andrei Vladimir

    The aerospace industry is motivated to reduce fuel consumption in large transport aircraft, mainly through drag reduction. The main objective of the global project is the development of an active control system of wing airfoil geometry during flight in order to allow drag reduction. Drag reduction on a wing can be achieved through modifications in the laminar-to-turbulent flow transition point position, which should be situated as close as possible to the trailing edge of the airfoil wing. As the transition point plays a crucial part in this project, this work focuses on the control of its position on the airfoil, as an effect of controlling the deflection of a morphing wing airfoil equipped with a flexible skin. The paper presents the modeling and the experimental testing of the aerodynamic performance of a morphing wing, starting from the design concept phase all the way to the bench and wind tunnel tests phases. Several wind tunnel test runs for various Mach numbers and angles of attack were performed in the 6 x 9 ft2 wind tunnel at the Institute for Aerospace Research at the National Research Council Canada. A rectangular finite aspect ratio wing, having a morphing airfoil cross-section due to a flexible skin installed on the upper surface of the wing, was instrumented with Kulite transducers. The Mach number varied from 0.2 to 0.3 and the angle of attack between -1° and 2°. Unsteady pressure signals were recorded and analyzed and a thorough comparison, in terms of mean pressure coefficients and their standard deviations, was performed against theoretical predictions, using the XFoil computational fluid dynamics code. The acquired pressure data was analyzed through custom-made software created with Matlab/Simulink in order to detect the noise magnitude in the surface airflow and to localize the transition point position on the wing upper surface. This signal processing was necessary in order to detect the Tollmien-Schlichting waves responsible for triggering

  15. Enhancing Concept Comprehension in a Web-Based Course Using a Framework Integrating the Learning Cycle with Variation Theory

    ERIC Educational Resources Information Center

    Hsu, Chih-Chao; Wang, Tzone-I

    2014-01-01

    Concept comprehension is an important foundation for more complex thoughts. To enhance concept comprehension, teachers of traditional classrooms have been using instructional strategies and specific course designs, which have been proven effective. It initiates a hypothesis that integrating instructional strategies in the course designs of an…

  16. A reappraisal of the terrestrial nitrogen cycle: what can we learn by extracting concepts from Gaia theory?

    PubMed

    Cresser, Malcolm S; Aitkenhead, Matthew J; Mian, Ishaq A

    2008-08-01

    Although soil scientists and most environmental scientists are acutely aware of the interactions between the cycling of carbon and nitrogen, for conceptual convenience when portraying the nitrogen cycle in text books the N cycle tends to be considered in isolation from its interactions with the cycling of other elements and water, usually as a snap shot at the current time; the origins of dinitrogen are rarely considered, for example. The authors suggest that Lovelock's Gaia hypothesis provides a useful and stimulating framework for consideration of the terrestrial nitrogen cycle. If it is used, it suggests that urbanization and management of sewage, and intensive animal rearing are probably bigger global issues than nitrogen deposition from fossil fuel combustion, and that plant evolution may be driven by the requirement of locally sustainable and near optimal soil mineral N supply dynamics. This may, in turn, be partially regulating global carbon and oxygen cycles. It is suggested that pollutant N deposition may disrupt this essential natural plant and terrestrial ecosystem evolutionary process, causing biodiversity change. Interactions between the Earth and other bodies in the solar system, and possibly beyond, also need to be considered in the context of the global N cycle over geological time scales. This is because of direct potential impacts on the nitrogen content of the atmosphere, potential long-term impacts of past boloid collisions on plate tectonics and thus on global N cycling via subduction and volcanic emissions, and indirect effects upon C, O and water cycling that all may impact upon the N cycle in the long term. PMID:18678394

  17. A power and load priority control concept as applied to a Brayton cycle turbo-electric generator.

    NASA Technical Reports Server (NTRS)

    Kelsey, E. L.; Young, R. N.

    1972-01-01

    This paper describes a system to regulate the speed and power output of a Brayton Cycle Power System under varying load. A typical user load profile is applied and a simple load priority and parasitic load is used for system regulation. Power storage is provided by batteries with charge and discharge converters to demonstrate support capability. The breadboard system is tested with the Brayton Cycle Demonstrator at the National Aeronautics and Space Administration, Manned Space Craft Center, Houston, Texas.

  18. La problématique de la maîtrise de l'inventaire plutonium et actinides mineurs dans le cycle du combustible nucléaire

    NASA Astrophysics Data System (ADS)

    Mouney, Henri

    2002-10-01

    The mastering of the plutonium and minor actinides inventory in the French Nuclear Cycle is based on a progressive approach from the present status, dealing with the partial reprocessing of spent fuels and the recycling of Pu in the MOX assemblies loaded in the 20 licensed PWRs. This strategy keeps the door open long-term, for example, for the eventual multirecycling of excess Pu in dedicated new assemblies, such as APA or CORAIL in order to stabilise the Pu inventory in the fuel cycle or allow its utilization in new types of fast reactors. Presently, in the framework of 1991 law, scenario studies relying on present and/or innovative technologies are carried out in order to transmute both Pu and minor actinides, thus minimising the quantities to be for disposal. To cite this article: H. Mouney, C. R. Physique 3 (2002) 773-782.

  19. Assessment of possible cycle lengths for fully-ceramic micro-encapsulated fuel-based light water reactor concepts

    SciTech Connect

    Sen, R. S.; Pope, M. A.; Ougouag, A. M.; Pasamehmetoglu, K.; Venneri, F.

    2012-07-01

    The use of TRISO-particle-based dispersion fuel within SiC matrix and cladding materials has the potential to allow the design of extremely safe LWRs with accident-tolerant fuel. This paper examines the feasibility of LWR-like cycle length for such a low enriched uranium fuel with the imposed constraint of strictly retaining the original geometry of the fuel pins and assemblies. The motivation for retaining the original geometry is to provide the ability to incorporate the fuel 'as-is' into existing LWRs while retaining their thermal-hydraulic characteristics. The feasibility of using this fuel is assessed by looking at cycle lengths and fuel failure rates. Other considerations (e.g., safety parameters, etc.) were not considered at this stage of the study. The study includes the examination of different TRISO kernel diameters without changing the coating layer thicknesses. The study shows that a naive use of UO{sub 2} results in cycle lengths too short to be practical for existing LWR designs and operational demands. Increasing fissile inventory within the fuel compacts shows that acceptable cycle lengths can be achieved. In this study, starting with the recognized highest packing fraction practically achievable (44%), higher enrichment, larger fuel kernel sizes, and the use of higher density fuels have been evaluated. The models demonstrate cycle lengths comparable to those of ordinary LWRs. As expected, TRISO particles with extremely large kernels are shown to fail under all considered scenarios. In contrast, the designs that do not depart too drastically from those of the nominal NGNP HTR fuel TRISO particles are shown to perform satisfactorily and display a high rate of survival under all considered scenarios. Finally, it is recognized that relaxing the geometry constraint will result in satisfactory cycle lengths even using UO{sub 2}-loaded TRISO particles-based fuel with enrichment at or below 20 w/o. (authors)

  20. ASSESSMENT OF POSSIBLE CYCLE LENGTHS FOR FULLY-CERAMIC MICRO-ENCAPSULATED FUEL-BASED LIGHT WATER REACTOR CONCEPTS

    SciTech Connect

    R. Sonat Sen; Michael A. Pope; Abderrafi M. Ougouag; Kemal Pasamehmetoglu; Francesco Venneri

    2012-04-01

    The use of TRISO-particle-based dispersion fuel within SiC matrix and cladding materials has the potential to allow the design of extremely safe LWRs with failure-proof fuel. This paper examines the feasibility of LWR-like cycle length for such a low enriched uranium fuel with the imposed constraint of strictly retaining the original geometry of the fuel pins and assemblies. The motivation for retaining the original geometry is to provide the ability to incorporate the fuel 'as-is' into existing LWRs while retaining their thermal-hydraulic characteristics. The feasibility of using this fuel is assessed by looking at cycle lengths and fuel failure rates. Other considerations (e.g., safety parameters, etc.) were not considered at this stage of the study. The study includes the examination of different TRISO kernel diameters without changing the coating layer thicknesses. The study shows that a naive use of UO{sub 2} results in cycle lengths too short to be practical for existing LWR designs and operational demands. Increasing fissile inventory within the fuel compacts shows that acceptable cycle lengths can be achieved. In this study, starting with the recognized highest packing fraction practically achievable (44%), higher enrichment, larger fuel kernel sizes, and the use of higher density fuels have been evaluated. The models demonstrate cycle lengths comparable to those of ordinary LWRs. As expected, TRISO particles with extremely large kernels are shown to fail under all considered scenarios. In contrast, the designs that do not depart too drastically from those of the nominal NGNP HTR fuel TRISO particles are shown to perform satisfactorily and display a high rates of survival under all considered scenarios. Finally, it is recognized that relaxing the geometry constraint will result in satisfactory cycle lengths even using UO{sub 2}-loaded TRISO particles-based fuel with enrichment at or below 20 w/o.

  1. Fostering Third-Grade Students' Use of Scientific Models with the Water Cycle: Elementary Teachers' Conceptions and Practices

    ERIC Educational Resources Information Center

    Vo, Tina; Forbes, Cory T.; Zangori, Laura; Schwarz, Christina V.

    2015-01-01

    Elementary teachers play a crucial role in supporting and scaffolding students' model-based reasoning about natural phenomena, particularly complex systems such as the water cycle. However, little research exists to inform efforts in supporting elementary teachers' learning to foster model-centered, science learning environments. To address this…

  2. The Relationship Between the Learning Style Perceptual Preferences of Urban Fourth Grade Children and the Acquisition of Selected Physical Science Concepts Through Learning Cycle Instructional Methodology.

    NASA Astrophysics Data System (ADS)

    Adams, Kenneth Mark

    The purpose of this research was to investigate the relationship between the learning style perceptual preferences of fourth grade urban students and the attainment of selected physical science concepts for three simple machines as taught using learning cycle methodology. The sample included all fourth grade children from one urban elementary school (N = 91). The research design followed a quasi-experimental format with a single group, equivalent teacher demonstration and student investigation materials, and identical learning cycle instructional treatment. All subjects completed the Understanding Simple Machines Test (USMT) prior to instructional treatment, and at the conclusion of treatment to measure student concept attainment related to the pendulum, the lever and fulcrum, and the inclined plane. USMT pre and post-test scores, California Achievement Test (CAT-5) percentile scores, and Learning Style Inventory (LSI) standard scores for four perceptual elements for each subject were held in a double blind until completion of the USMT post-test. The hypothesis tested in this study was: Learning style perceptual preferences of fourth grade students as measured by the Dunn, Dunn, and Price Learning Style Inventory (LSI) are significant predictors of success in the acquisition of physical science concepts taught through use of the learning cycle. Analysis of pre and post USMT scores, 18.18 and 30.20 respectively, yielded a significant mean gain of +12.02. A controlled stepwise regression was employed to identify significant predictors of success on the USMT post-test from among USMT pre-test, four CAT-5 percentile scores, and four LSI perceptual standard scores. The CAT -5 Total Math and Total Reading accounted for 64.06% of the variance in the USMT post-test score. The only perceptual element to act as a significant predictor was the Kinesthetic standard score, accounting for 1.72% of the variance. The study revealed that learning cycle instruction does not appear

  3. Reactor moderator, pressure vessel, and heat rejection system of an open-cycle gas core nuclear rocket concept

    NASA Technical Reports Server (NTRS)

    Taylor, M. F.; Whitmarsh, C. L., Jr.; Sirocky, P. J., Jr.; Iwanczyke, L. C.

    1973-01-01

    A preliminary design study of a conceptual 6000-megawatt open-cycle gas-core nuclear rocket engine system was made. The engine has a thrust of 196,600 newtons (44,200 lb) and a specific impulse of 4400 seconds. The nuclear fuel is uranium-235 and the propellant is hydrogen. Critical fuel mass was calculated for several reactor configurations. Major components of the reactor (reflector, pressure vessel, and waste heat rejection system) were considered conceptually and were sized.

  4. Mechanisms and Concepts Paving the Way towards a Complete Transport Cycle of Plant Vacuolar Sorting Receptors[W][OA

    PubMed Central

    De Marcos Lousa, Carine; Gershlick, David C.; Denecke, Jurgen

    2012-01-01

    Delivery of proteins to the lytic vacuole in plants is a complex cascade of selective interactions that specifically excludes residents of the endoplasmic reticulum and secreted proteins. Vacuolar transport must be highly efficient to avoid mistargeting of hydrolytic enzymes to locations where they could be harmful. While plant vacuolar sorting signals have been well described for two decades, it is only during the last 5 years that a critical mass of data was gathered that begins to reveal how vacuolar sorting receptors (VSRs) may complete a full transport cycle. Yet, the field is far from reaching a consensus regarding the organelles that could be involved in vacuolar sorting, their potential biogenesis, and the ultimate recycling of membranes and protein machinery that maintain this pathway. This review will highlight the important landmarks in our understanding of VSR function and compare recent transport models that have been proposed so that an emerging picture of plant vacuolar sorting mechanisms can be drawn. PMID:22570446

  5. Le cycle de l'eau et les activités au sein de l'espace rural. Enjeux globaux, solutions locales et régionales

    NASA Astrophysics Data System (ADS)

    Perrier, Alain; Tuzet, Andrée

    2005-02-01

    The analysis of the water cycle emphasizes the weight of surface evaporation compared to rain and the weight of water availability compared to evaporation. The ocean is a huge machine producing water vapour contrary to the continents, where evaporation is limited by plants that must shield themselves from drying and particularly by bare soils where the surface drying slows down the water losses. The availability of water for the biosphere depends on the difference between rain and evaporation. This difference, often called 'net supply', can be modified by anthropogenic actions on the vegetation; for example, the anthropogenic actions such as drying climate (reducing evapotranspiration) increases the net supply; on the opposite, the large development of more and more covering vegetation (arboreous system, bocages, savannah...) decreases the net supply (larger surface evapotranspiration all over the year). Moreover, the feedback between climate and continental interface can modify the rainfall pattern and the thermal equilibrium, leading ecosystems to extreme situations such as drying climate and desertification (ET lower and lower) or equilibrium situations corresponding to large development of vegetation (ET close to EP). The anthropogenic pressure and the human food requirements lead human beings to keep nearly the whole available water of the biosphere, particularly to practise irrigated agriculture. This practise is on average two times more efficient than the rainy agriculture (which is why it is attractive); moreover, its water efficiency decreases according to the environment and its aridity. Except for arboreous systems and agroforestry, agriculture is always a system that leads more or less towards aridity, but we have to bring it under control and to make it sustainable. A good management of the whole rain requires an efficient organization of the territory to optimise the water consumption in order to protect the environment and its biodiversity, to

  6. Quantification of urban metabolism through coupling with the life cycle assessment framework: concept development and case study

    NASA Astrophysics Data System (ADS)

    Goldstein, Benjamin; Birkved, Morten; Quitzau, Maj-Britt; Hauschild, Michael

    2013-09-01

    Cities now consume resources and produce waste in amounts that are incommensurate with the populations they contain. Quantifying and benchmarking the environmental impacts of cities is essential if urbanization of the world’s growing population is to occur sustainably. Urban metabolism (UM) is a promising assessment form in that it provides the annual sum material and energy inputs, and the resultant emissions of the emergent infrastructural needs of a city’s sociotechnical subsystems. By fusing UM and life cycle assessment (UM-LCA) this study advances the ability to quantify environmental impacts of cities by modeling pressures embedded in the flows upstream (entering) and downstream (leaving) of the actual urban systems studied, and by introducing an advanced suite of indicators. Applied to five global cities, the developed UM-LCA model provided enhanced quantification of mass and energy flows through cities over earlier UM methods. The hybrid model approach also enabled the dominant sources of a city’s different environmental footprints to be identified, making UM-LCA a novel and potentially powerful tool for policy makers in developing and monitoring urban development policies. Combining outputs with socioeconomic data hinted at how these forces influenced the footprints of the case cities, with wealthier ones more associated with personal consumption related impacts and poorer ones more affected by local burdens from archaic infrastructure.

  7. Why the Learning Cycle?

    ERIC Educational Resources Information Center

    Marek, Edmund A.

    2008-01-01

    The learning cycle is a way to structure inquiry in school science and occurs in several sequential phases. A learning cycle moves children through a scientific investigation by having them first explore materials, then construct a concept, and finally apply or extend the concept to other situations. Why the learning cycle? Because it is a…

  8. Advanced radiator concepts

    NASA Technical Reports Server (NTRS)

    Diem-Kirsop, P. S.

    1985-01-01

    The liquid droplet radiator and the liquid belt radiator currently under study by the NASA LeRC are discussed. These advanced concepts offer benefits in reduced mass, compact stowage, and ease of deployment. Operation and components of the radiators are described, heat transfer characteristics are discussed, and critical technologies are identified. The impact of the radiators on large power systems is also assessed.

  9. A 1.26 μW Cytomimetic IC Emulating Complex Nonlinear Mammalian Cell Cycle Dynamics: Synthesis, Simulation and Proof-of-Concept Measured Results.

    PubMed

    Houssein, Alexandros; Papadimitriou, Konstantinos I; Drakakis, Emmanuel M

    2015-08-01

    Cytomimetic circuits represent a novel, ultra low-power, continuous-time, continuous-value class of circuits, capable of mapping on silicon cellular and molecular dynamics modelled by means of nonlinear ordinary differential equations (ODEs). Such monolithic circuits are in principle able to emulate on chip, single or multiple cell operations in a highly parallel fashion. Cytomimetic topologies can be synthesized by adopting the Nonlinear Bernoulli Cell Formalism (NBCF), a mathematical framework that exploits the striking similarities between the equations describing weakly-inverted Metal-Oxide Semiconductor (MOS) devices and coupled nonlinear ODEs, typically appearing in models of naturally encountered biochemical systems. The NBCF maps biological state variables onto strictly positive subthreshold MOS circuit currents. This paper presents the synthesis, the simulation and proof-of-concept chip results corresponding to the emulation of a complex cellular network mechanism, the skeleton model for the network of Cyclin-dependent Kinases (CdKs) driving the mammalian cell cycle. This five variable nonlinear biological model, when appropriate model parameter values are assigned, can exhibit multiple oscillatory behaviors, varying from simple periodic oscillations, to complex oscillations such as quasi-periodicity and chaos. The validity of our approach is verified by simulated results with realistic process parameters from the commercially available AMS 0.35 μm technology and by chip measurements. The fabricated chip occupies an area of 2.27 mm2 and consumes a power of 1.26 μW from a power supply of 3 V. The presented cytomimetic topology follows closely the behavior of its biological counterpart, exhibiting similar time-dependent solutions of the Cdk complexes, the transcription factors and the proteins. PMID:26316209

  10. Lighting innovations in concept cars

    NASA Astrophysics Data System (ADS)

    Berlitz, Stephan; Huhn, Wolfgang

    2005-02-01

    Concept cars have their own styling process. Because of the big media interest they give a big opportunity to bring newest technology with styling ideas to different fairgrounds. The LED technology in the concept cars Audi Pikes Peak, Nuvolari and Le Mans will be explained. Further outlook for the Audi LED strategy starting with LED Daytime Running Lamp will be given. The close work between styling and technical engineers results in those concept cars and further technical innovations based on LED technologies.

  11. Le Chatelier's principle in replicator dynamics

    NASA Astrophysics Data System (ADS)

    Allahverdyan, Armen E.; Galstyan, Aram

    2011-10-01

    The Le Chatelier principle states that physical equilibria are not only stable, but they also resist external perturbations via short-time negative-feedback mechanisms: a perturbation induces processes tending to diminish its results. The principle has deep roots, e.g., in thermodynamics it is closely related to the second law and the positivity of the entropy production. Here we study the applicability of the Le Chatelier principle to evolutionary game theory, i.e., to perturbations of a Nash equilibrium within the replicator dynamics. We show that the principle can be reformulated as a majorization relation. This defines a stability notion that generalizes the concept of evolutionary stability. We determine criteria for a Nash equilibrium to satisfy the Le Chatelier principle and relate them to mutualistic interactions (game-theoretical anticoordination) showing in which sense mutualistic replicators can be more stable than (say) competing ones. There are globally stable Nash equilibria, where the Le Chatelier principle is violated even locally: in contrast to the thermodynamic equilibrium a Nash equilibrium can amplify small perturbations, though both types of equilibria satisfy the detailed balance condition.

  12. Current Concepts in Conception Control

    PubMed Central

    Ringrose, C. A. Douglas

    1963-01-01

    The progressive increase in world population has become a most urgent global problem in recent years. Man has, however, been interested in controlling his reproductivity at the family level for many centuries. Historical aspects of this saga are reviewed. The modern era of conception control was ushered in by Makepeace et al. in 1937 when ovulation inhibition by progesterone was demonstrated. Confirmation of this by Pincus and associates, and development of the potent oral progestational agents, the 19-norsteroids, have made efficient reliable contraception a reality. Experience with one of these agents (Ortho-Novum, 2 mg.) in 115 patients through 805 cycles is presented. Conception control was 100% effective at this dosage. Side effects were minimal. Only three of the women discontinued the tablets because of these effects. All but five in this group of 115 preferred the oral contraceptives to methods previously employed. PMID:13973987

  13. Le Indeterminacy in Spanish.

    ERIC Educational Resources Information Center

    Foster, David William

    The standard treatment of object pronouns in Latin American Spanish assigns a direct-object function to "lo" and "la" and an indirect-object function to "le." This study challenges this descriptive attribution in light of the contradictory and refractory evidence in Spanish morphosyntax. It is suggested that more detailed research, especially…

  14. Le Figaro. Revised.

    ERIC Educational Resources Information Center

    Crawford, Linda

    These instructional materials are designed for students with some French reading skills and vocabulary in late beginning or early intermediate senior high school French. The objectives are to introduce students to a French newspaper, "Le Figaro," and develop reading skills for skimming, gathering specific information, and relying on cognates. The…

  15. Regenerative Heater Optimization for Steam Turbo-Generation Cycles of Generation IV Nuclear Power Plants with a Comparison of Two Concepts for the Westinghouse International Reactor Innovative and Secure (IRIS)

    SciTech Connect

    Williams, W.C.

    2002-08-01

    The intent of this study is to discuss some of the many factors involved in the development of the design and layout of a steam turbo-generation unit as part of a modular Generation IV nuclear power plant. Of the many factors involved in the design and layout, this research will cover feed water system layout and optimization issues. The research is arranged in hopes that it can be generalized to any Generation IV system which uses a steam powered turbo-generation unit. The research is done using the ORCENT-II heat balance codes and the Salisbury methodology to be reviewed herein. The Salisbury methodology is used on an original cycle design by Famiani for the Westinghouse IRIS and the effects due to parameter variation are studied. The vital parameters of the Salisbury methodology are the incremental heater surface capital cost (S) in $/ft{sup 2}, the value of incremental power (I) in $/kW, and the overall heat transfer coefficient (U) in Btu/ft{sup 2}-degrees Fahrenheit-hr. Each is varied in order to determine the effects on the cycles overall heat rate, output, as well as, the heater surface areas. The effects of each are shown. Then the methodology is then used to compare the optimized original Famiani design consisting of seven regenerative feedwater heaters with an optimized new cycle concept, INRC8, containing four regenerative heaters. The results are shown. It can be seen that a trade between the complexity of the seven stage regenerative Famiani cycle and the simplicity of the INRC8 cycle can be made. It is desired that this methodology can be used to show the ability to evaluate modularity through the value of size a complexity of the system as well as the performance. It also shows the effectiveness of the Salisbury methodology in the optimization of regenerative cycles for such an evaluation.

  16. Integral Fast Reactor concept

    SciTech Connect

    Till, C.E.; Chang, Y.I.

    1986-01-01

    The Integral Fast Reactor (IFR) is an innovative LMR concept, being developed at Argonne National Laboratory, that fully exploits the inherent properties of liquid metal cooling and metallic fuel to achieve breakthroughs in economics and inherent safety. This paper describes key features and potential advantages of the IFR concept, technology development status, fuel cycle economics potential, and future development path.

  17. Le mouvement du pôle

    NASA Astrophysics Data System (ADS)

    Bizouard, Christian

    2012-03-01

    Les variations de la rotation terrestre. En conditionnant à la fois notre vie quotidienne, notre perception du ciel, et bon nombre de phénomènes géophysiques comme la formation des cyclones, la rotation de la Terre se trouve au croisement de plusieurs disciplines. Si le phenomena se faisait uniformément, le sujet serait vite discuté, mais c'est parce que la rotation terrestre varie, même imperceptiblement pour nos sens, dans sa vitesse angulaire comme dans la direction de son axe, qu'elle suscite un grand intérêt. D'abord pour des raisons pratiques : non seulement les aléas de la rotation terrestre modi_ent à la longue les pointés astrométriques à un instant donné de la journée mais in_uencent aussi les mesures opérées par les techniques spatiales ; en consequence l'exploitation de ces mesures, par exemple pour déterminer les orbites des satellites impliqués ou pratiquer le positionnement au sol, nécessite une connaissance précise de ces variations. Plus fondamentalement, elles traduisent les propriétés globales de la Terre comme les processus physiques qui s'y déroulent, si bien qu'en analysant les causes des fluctuations observées, on dispose d'un moyen de mieux connaître notre globe. La découverte progressive des fluctuations de la rotation de la Terre a une longue histoire. Sous l'angle des techniques d'observation, trois époques se pro-celle du pointé astrométrique à l'oeil nu, à l'aide d'instruments en bois ou métalliques (quart de cercle muraux par exemple). À partir du XVIIe siècle débute l'astrométrie télescopique dont les pointés sont complétés par des datations de plus en plus précises grâce à l'invention d'horloges régulées par balancier. Cette deuxième époque se termine vers 1960, avec l'avènement des techniques spatiales : les pointés astrométriques sont délaissés au profit de la mesure ultra-précise de durées ou de fréquences de signaux électromagnétiques, grâce à l'invention des horloges

  18. MODeLeR: A Virtual Constructivist Learning Environment and Methodology for Object-Oriented Design

    ERIC Educational Resources Information Center

    Coffey, John W.; Koonce, Robert

    2008-01-01

    This article contains a description of the organization and method of use of an active learning environment named MODeLeR, (Multimedia Object Design Learning Resource), a tool designed to facilitate the learning of concepts pertaining to object modeling with the Unified Modeling Language (UML). MODeLeR was created to provide an authentic,…

  19. Cg/Stability Map for the Reference H Cycle 3 Supersonic Transport Concept Along the High Speed Research Baseline Mission Profile

    NASA Technical Reports Server (NTRS)

    Giesy, Daniel P.; Christhilf, David M.

    1999-01-01

    A comparison is made between the results of trimming a High Speed Civil Transport (HSCT) concept along a reference mission profile using two trim modes. One mode uses the stabilator. The other mode uses fore and aft placement of the center of gravity. A comparison is make of the throttle settings (cruise segments) or the total acceleration (ascent and descent segments) and of the drag coefficient. The comparative stability of trimming using the two modes is also assessed by comparing the stability margins and the placement of the lateral and longitudinal eigenvalues.

  20. Design considerations for space radiators based on the liquid sheet (LSR) concept

    NASA Technical Reports Server (NTRS)

    Juhasz, Albert J.; Chubb, Donald L.

    1991-01-01

    Concept development work on space heat rejection subsystems tailored to the requirements of various space power conversion systems is proceeding over a broad front of technologies at NASA LeRC. Included are orbital and planetary surface based radiator concepts utilizing pumped loops, a variety of heat pipe radiator concepts, and the innovative liquid sheet radiator (LSR). The basic feasibility of the LSR concept was investigated in prior work which generated preliminary information indicating the suitability of the LSR concept for space power systems requiring cycle reject heat to be radiated to the space sink at low-to-mid temperatures (300 to 400 K), with silicon oils used for the radiator working fluid. This study is directed at performing a comparative examination of LSR characteristics as they affect the basic design of low earth orbit solar dynamic power conversion systems. The power systems considered were based on the closed Brayton (CBC) and the Free Piston Stirling (FPS) cycles, each with a power output of 2 kWe and using previously tested silicone oil (Dow-Corning Me2) as the radiator working fluid. Conclusions indicate that, due to its ability for direct cold end cooling, an LSR based heat rejection subsystem is far more compatible with a Stirling space power system than with a CBC, which requires LSR coupling by means of an intermediate gas/liquid heat exchanger and adjustment of cycle operating conditions.

  1. LeRC in-house experimental research

    NASA Technical Reports Server (NTRS)

    Lyons, Valerie J.

    1992-01-01

    The topics covered include the following: LeRC in-house experimental research; combustion concepts; schedule for in-house experiments; lean premixed prevaporized combustion; comparisons of low NO(x) lean premixed/prevaporized data; rich burn/quick quench/lean burn (RQL); RQL combustion; fuel rich catalytic combustion; advanced diagnostics; and ceramic matrix liner test rig.

  2. Thermochemical cycles

    NASA Technical Reports Server (NTRS)

    Funk, J. E.; Soliman, M. A.; Carty, R. H.; Conger, W. L.; Cox, K. E.; Lawson, D.

    1975-01-01

    The thermochemical production of hydrogen is described along with the HYDRGN computer program which attempts to rate the various thermochemical cycles. Specific thermochemical cycles discussed include: iron sulfur cycle; iron chloride cycle; and hybrid sulfuric acid cycle.

  3. Une étude expérimentale sur la variation du taux d'anticorps sériques suivant le cycle évolutif des oestres du cheval

    PubMed Central

    Viviers, P. L.; Elazhary, M. A. S. Y.; Lagacé, A.; Roy, R. S.; Tremblay, A.

    1974-01-01

    The changes of antibody titers in the sera of colts infested naturally or artificially with Gasterophilus have been determined in relation to the life cycle of this arthropod using passive hemagglutination, complement fixation, double diffusion techniques and saline extracts of antigens from the third larval stages of Gasterophilus intestinalis and G. nasalis. In the sera of the infected animals the hemagglutinating antibodies were present at low titers at the third week post-infestation by using somatic extract of G. intestinalis and at the seventh week in case of G. nasalis. At eight weeks post-infestation the antibody titers reached their maximum 1:8192 (G. intestinalis) and 1:4096 (G. nasalis), then dropped at 12 weeks post-infestation. The complement fixing antibodies were present occasionally between the seventh and 11th weeks after infestation. Precipitating antibodies were absent in all sera. PMID:4277126

  4. PFB coal fired combined cycle development program. Advanced hot gas cleanup concept evaluation (Task 4. 3). Volume B. Developmental cyclone evaluation

    SciTech Connect

    Not Available

    1980-02-01

    This report summarizes the results of cold flow model testing of a conventional reverse-flow cyclone containing several developmental features designed to improve its separative performance. The four advanced features evaluated were: Outlet Scroll Skimming - to remove particles from the high dust concentration region at the periphery of the outlet dust; Base Purge - to reduce reentrainment of dust from the disengagement hopper; Increased Outlet Duct Engagement - to reduce short-circuiting of the inlet dust into the outlet; and Vortex Shield - to stabilize the point of vortex attachment at the cyclone base and thus reduce base pickup. A schematic of the advanced cyclone, showing the various developmental features, is provided. The results of the cold flow experiments showed that substantial improvement (approximately 30% reduction in exhaust emission) could be obtained from outlet skimming or from increased engagement of the exhaust dust. Furthermore, the effects of these features are additive so that about 60% overall reduction in emissions could be achieved by incorporating both of these elements. On the other hand, the vortex shield and the base purge had little effect on the separative performance. Almost all of the experimental results exhibited strong electrostatic influence. At high flowrates, the separative performance of the cyclone decreased as the flowrate was reduced, as expected from cyclone theory. Although the improvements obtained with the developmental cyclone are significant, further improvements appear possible with the Air Shield cyclone and the Electrocyclone. Consequently, subsequent efforts under the CFCC program were focused on these concepts.

  5. Concept Formation.

    ERIC Educational Resources Information Center

    Vaidya, Narendera

    This document, published in India by the Regional College of Education, deals with 13 subjects: the tough context (thinking), definitions of concept, functions of concept, the process of concept formation, discriminant learning, mediation process, second signalling system, factors affecting concept formation, studies in concept formation, the…

  6. Pattern of induced estrus and conception rate following Ovsynch and Ovsynch based gonadotropin-releasing hormone treatments initiated on day 6 of estrous cycle in repeat breeding crossbred cows

    PubMed Central

    Ahmed, N.; Kathiresan, D.; Ahmed, F. A.; Lalrintluanga, K.; Mayengbam, P.; Gali, J. M.

    2016-01-01

    Aim: The aim was to evaluate the estrus response, incidence of accessory corpus luteum formation and fertility following different hormonal protocols in repeat breeding crossbred cows. Materials and Methods: This study was carried out on 24 repeat breeding crossbred cows allotted into four groups. Cows of Group I was not given any treatment, Group II was treated with gonadotropin-releasing hormone (GnRH) injection on day 6 post-estrus, Group III was treated with Ovsynch protocol, and Group IV was treated with Ovsynch based GnRH treatment. Estrus responses such as duration, onset, percentage, and intensity of estrus were recorded during the study. The incidence of accessory corpus luteum was recorded per rectally on day 7 after first and additional GnRH of Ovsynch treatment. The conception rate for all groups was calculated by the absence of estrus and on day 45 after artificial insemination (AI) per rectum. Serum samples were collected at AI and day 12 post-AI in Group I and II. Serum samples were also collected at GnRH, Prostaglandin F2α (PGF2α), timed AI (TAI) and day 12 post-TAI in Group III and IV. Results: Ovsynch and Ovsynch based GnRH treatments are resulted in 100.00% induction of estrus after the PGF2α injection. Onset of induced estrus after the PGF2α injection for Group III and IV was recorded as 48.750±0.713 and 51.472±1.989 h, respectively, and it was not significant. There was no significant difference in duration of estrus among the groups. The incidence of intermediate estrus intensity was found to be highest. All the cows showed the incidence of formation of accessory corpus luteum subsequent to GnRH treatment on day 6 of the estrous cycle in Group II, III, and IV. The conception rate was 0.00%, 16.67%, 50.00%, and 50.00% in Group I, II, III, and IV, respectively. Conclusion: Ovsynch and Ovsynch based GnRH treatments initiated on day 6 of estrous cycle capable of responding with a higher percentage of ovulation and formation of accessory

  7. Le syndrome d’alcoolisme foetal

    PubMed Central

    2002-01-01

    L’alcool est un tératogène physique et comportemental. Le syndrome d’alcoolisme foetal (SAF) est un trouble courant mais encore sous-diagnostiqué découlant de la consommation d’alcool par la mère pendant la grossesse. Bien qu’il puisse être prévenu, le SAF est également invalidant. Même si le SAF est présent dans tous les groupes socioéconomiques du Canada, sa prévalence est élevée dans certaines communautés inuites et des Premières nations du Canada. Le présent énoncé porte sur la prévention, le diagnostic, le dépistage précoce et la prise en charge du SAF par les professionnels de la santé. La prévention du SAF doit s’effectuer à deux échelons. La prévention primaire consiste à éliminer le SAF par une formation en classe ou dans la collectivité et à inciter les femmes à éviter de consommer de l’alcool avant la conception et pendant la grossesse. La prévention secondaire consiste à repérer les femmes qui boivent pendant leur grossesse et à réduire leur consommation. Le présent énoncé décrit plusieurs stratégies de dépistage, dont la stratégie T-ACE (tolérance-agacement, réduction, éveil). Les dispensateurs de soins devraient recommander l’abstinence dès la première visite prénatale. Un envoi rapide en consultation en vue de traiter l’alcoolisme est recommandé pour les femmes enceintes incapables d’arrêter de boire. Le présent énoncé décrit le diagnostic de SAF, de SAF partiel ou atypique, d’anomalies congénitales et de troubles neurodéveloppementaux reliés à l’alcool. En cas d’exposition à l’alcool in utero, un diagnostic de SAF devrait être envisagé en présence d’un retard de croissance courant ou antérieur, de certaines anomalies faciales touchant la lèvre supérieure et les yeux et d’anomalies neurodéveloppementales. Ces caractéristiques sont mieux quantifiées au moyen d’une méthode diagnostique à quatre chiffres. Des stratégies de dépistage précoce des

  8. Introduction to combined cycles

    NASA Astrophysics Data System (ADS)

    Moore, M. J.

    Ideas and concepts underlying the technology of combined cycles including the scientific principles involved and the reasons these cycles are in fashion at the present time, are presented. A cycle is a steady flow process for conversion of heat energy into work, in which a working medium passes through a range of states, returning to its original state. Cycles for power production are the steam cycle, which is a closed cycle, and the gas turbine, which represents an open cycle. Combined cycle thermodynamic parameters, are discussed. The general arrangement of the plant is outlined and important features of their component parts described. The scope for future development is discussed. It is concluded that for the next few years the natural gas fired combined cycle will be the main type of plant installed for electricity generation and cogeneration. Whilst gas turbines may not increase substantially in unit size, there remains scope for further increase in firing temperature with consequent increase in cycle performance. However the larger global reserves of coal are providing an incentive to the development of plant for clean coal combustion using the inherent advantage of the combined cycle to attain high efficiencies.

  9. NEP facilities (LeRC)

    NASA Astrophysics Data System (ADS)

    Vetrone, Robert H.

    The topics are presented in viewgraph form and include the following: the Electric Propulsion Research Building (no. 16) the Electric Power Laboratory (BLDG. 301); the Tank 6 Vacuum Facility; and test facilities for electric propulsion and LeRC.

  10. Le bégaiement

    PubMed Central

    Perez, Hector R.; Stoeckle, James H.

    2016-01-01

    Résumé Objectif Fournir une mise à jour sur l’épidémiologie, l’hérédité, la physiopathologie, le diagnostic et le traitement du bégaiement développemental. Qualité des données Une recherche d’études récentes ou non portant sur l’épidémiologie, l’hérédité, la physiopathologie, le diagnostic et le traitement du bégaiement développemental a été effectuée dans les bases de données MEDLINE et Cochrane. La plupart des recommandations s’appuient sur des études de petite envergure, des données probantes de qualité limitée ou des consensus. Message principal Le bégaiement est un trouble d’élocution fréquent chez les personnes de tous âges, il altère la fluidité verbale normale et l’enchaînement du discours. Le bégaiement a été lié à des différences de l’anatomie, du fonctionnement et de la régulation dopaminergique du cerveau qui seraient de source génétique. Il importe de poser le diagnostic avec attention et de faire les recommandations qui conviennent chez les enfants, car de plus en plus, le consensus veut que l’intervention précoce par un traitement d’orthophonie soit cruciale chez les enfants bègues. Chez les adultes, le bégaiement est lié à une morbidité psychosociale substantielle, dont l’anxiété sociale et une piètre qualité de vie. Les traitements pharmacologiques ont soulevé l’intérêt depuis quelques années, mais les données cliniques sont limitées. Le traitement des enfants et des adultes repose sur l’orthophonie. Conclusion De plus en plus de recherches ont tenté de lever le voile sur la physiopathologie du bégaiement. La meilleure solution pour les enfants et les adultes bègues demeure la recommandation à un traitement d’orthophonie.

  11. Le pompage optique naturel dans le milieu astrophysique

    NASA Astrophysics Data System (ADS)

    Pecker, J.-C.

    The title of this lecture abstracts only a part of it : the importance in astrophysics of the study of non-LTE situations has become considerable, as well in the stellar atmospheres as, still more, in the study of fortuitous coincidences as a mechanism of formation of emission line nebular spectra, or of molecular interstellar « masers ». Another part of this talk underlines the role of Kastler in his time, and describes his warm personality through his public reactions in front of the nuclear armement, of the Viet-Nam and Algerian wars, of the problems of political refugees... Kastler was a great scientist ; he was also a courageous humanist. 1976 : Les accords nucléaires du Brésil : allocution d'ouverture (19 mars). Colloque sur le sujet ci-dessus. 1976 : La promotion de la culture dans le nouvel ordre économique international, allocution à l'occasion d'une table ronde sur ce thème par l'UNESCO (23-27 juin 1976) ; « Sciences et Techniques », octobre 1976. 1979 : La bête immonde (avec J.-C. Pecker), « Le Matin », 20 mars. 1979 : Appel à nos ministres (avec J.-C. Pecker), « Le Monde », 13 décembre. 1979 : Le flou, le ténébreux, l'irrationnel (avec J.-C. Pecker), « Le Monde », 14 septembre. 1980 : Education à la paix, Préface, in : Publ. UNESCO. 1981 : Le vrai danger, « Le Monde », 6 août 1981. 1982 : Nucléaire civil et militaire, « Le Monde », 1er juin 1982. 1982 : Les scientifiques face à la perspective d'holocauste nucléaire (texte inédit). Le titre de cette communication en résume seulement une partie : l'importance prise en astrophysique par l'analyse des situations hors ETL est devenue considérable, qu'il s'agisse des atmosphères stellaires, ou plus encore, des coïncidences fortuites de la formation des spectres d'émission nébulaires, ou des « masers » moléculaires interstellaires. Une autre partie de cet exposé souligne lele de Kastler dans son époque, et décrit sa personnalité généreuse à travers ses r

  12. Developing an Action Concept Inventory

    ERIC Educational Resources Information Center

    McGinness, Lachlan P.; Savage, C. M.

    2016-01-01

    We report on progress towards the development of an Action Concept Inventory (ACI), a test that measures student understanding of action principles in introductory mechanics and optics. The ACI also covers key concepts of many-paths quantum mechanics, from which classical action physics arises. We used a multistage iterative development cycle for…

  13. Fragile cycles

    NASA Astrophysics Data System (ADS)

    Bonatti, Ch.; Díaz, L. J.

    We study diffeomorphisms f with heterodimensional cycles, that is, heteroclinic cycles associated to saddles p and q with different indices. Such a cycle is called fragile if there is no diffeomorphism close to f with a robust cycle associated to hyperbolic sets containing the continuations of p and q. We construct a codimension one submanifold of Diff(S×S) that consists of diffeomorphisms with fragile heterodimensional cycles. Our construction holds for any manifold of dimension ⩾4.

  14. Le LHC, un tunnel cosmique

    ScienceCinema

    None

    2011-10-06

    Et si la lumière au bout du tunnel du LHC était cosmique ? En d?autres termes, qu?est-ce que le LHC peut nous apporter dans la connaissance de l?Univers ? Car la montée en énergie des accélérateurs de particules nous permet de mieux appréhender l?univers primordial, chaud et dense. Mais dans quel sens dit-on que le LHC reproduit des conditions proches du Big bang ? Quelles informations nous apporte-t-il sur le contenu de l?Univers ? La matière noire est-elle détectable au LHC ? L?énergie noire ? Pourquoi l?antimatière accumulée au CERN est-elle si rare dans l?Univers ? Et si le CERN a bâti sa réputation sur l?exploration des forces faibles et fortes qui opèrent au sein des atomes et de leurs noyaux, est-ce que le LHC peut nous apporter des informations sur la force gravitationnelle qui gouverne l?évolution cosmique ? Depuis une trentaine d?années, notre compréhension de l?univers dans ses plus grandes dimensions et l?appréhension de son comportement aux plus petites distances sont intimement liées : en quoi le LHC va-t-il tester expérimentalement cette vision unifiée ? Tout public, entrée libre / Réservations au +41 (0)22 767 76 76

  15. Le Planetaire (Around the World)

    ERIC Educational Resources Information Center

    Rebouillet, Andre; And Others

    1977-01-01

    This section, "Le Planetaire," contains an interview with Anne Slack on the American Association of Teachers of French and contemporary French culture, a review of a dictionary of familiar French for students, dates to remember, events of interest to French teachers and a general bibliography. (Text is in French.) (AMH)

  16. Menstrual Cycle

    MedlinePlus

    ... Pregnancy This information in Spanish ( en español ) The menstrual cycle Day 1 starts with the first day of ... drop around Day 25 . This signals the next menstrual cycle to begin. The egg will break apart and ...

  17. In re LePage.

    PubMed

    2001-01-01

    Court Decision: 18 Pacific Reporter, 3d Series 1177; 2001 Mar 8 (date of decision). The Supreme Court of Wyoming held that the state Department of Health was not authorized to inquire about the sincerity of a mother's religious beliefs when determining whether her daughter was exempt from a public school immunization requirement. Susan LePage submitted a request to the Department of Health seeking to exempt her daughter from receiving the hepatitis B vaccination. The Department of Health inquired into the sincerity of LePage's religious beliefs against vaccination and determined that her objections were of a personal or philosophical nature and not on religious grounds. The Department of Health denied LePage's request. The Supreme Court of Wyoming held that state law requires the Department of Health to grant an exemption upon the submission of a written objection and does not allow the Department of Health to make an inquiry into the sincerity of the requestor's religious beliefs. The court balanced a valid state interest in protecting schoolchildren from disease with the relatively low number of requests for exemption and its confidence in parents to make decisions in the best interest of their children's physical and spiritual health. Since there was no justification within the statute to allow a religious inquiry, the court held that the Department of Health had exceeded its authority with LePage. Furthermore, state law did not require a religious waiver to exempt a child from this particular vaccine. The lower court's holding was reversed. PMID:16479706

  18. Teaching the Rock Cycle with Ease.

    ERIC Educational Resources Information Center

    Bereki, Debra

    2000-01-01

    Describes a hands-on lesson for teaching high school students the concept of the rock cycle using sedimentary, metamorphic, and igneous rocks. Students use a rock cycle diagram to identify pairs of rocks. From the rock cycle, students explain on paper how their first rock became the second rock and vice versa. (PVD)

  19. Does It Have a Life Cycle?

    ERIC Educational Resources Information Center

    Keeley, Page

    2010-01-01

    If life continues from generation to generation, then all plants and animals must go through a life cycle, even though it may be different from organism to organism. Is this what students have "learned," or do they have their own private conceptions about life cycles? The formative assessment probe "Does It Have a Life Cycle?" reveals some…

  20. Le Fevre [Le Fèvre; LeFebvre], Jean (1652-1706)

    NASA Astrophysics Data System (ADS)

    Murdin, P.

    2000-11-01

    Born in Lisieux, France, became an associate of JEAN PICARD and PHILIPPE DE LA HIRE, became a member of the Académie des Sciences and worked on rather routine work calculating ephemeredes, and surveying. Le Fevre accused La Hire of stealing his tables after Philippe de La Hire published Tabulae Astronomicae in 1687. In 1701, resentful at not having been named official publisher of ephemerides to ...

  1. Developing an action concept inventory

    NASA Astrophysics Data System (ADS)

    McGinness, Lachlan P.; Savage, C. M.

    2016-06-01

    We report on progress towards the development of an Action Concept Inventory (ACI), a test that measures student understanding of action principles in introductory mechanics and optics. The ACI also covers key concepts of many-paths quantum mechanics, from which classical action physics arises. We used a multistage iterative development cycle for incorporating expert and student feedback into successive revisions of the ACI. The student feedback, including think-aloud interviews, enabled us to identify their misconceptions about action physics.

  2. Tested Demonstrations: Thermodynamic Changes, Kinetics, Equilibrium, and LeChatelier's Principle.

    ERIC Educational Resources Information Center

    Gilbert, George L., Ed.

    1984-01-01

    Procedures for demonstrating thermodynamic changes, kinetics and reaction mechanisms, equilibrium, and LeChatelier's principle are presented. The only materials needed for these demonstrations are beakers, water, assorted wooden blocks of varying thickness, assorted rubber tubing, and a sponge. The concepts illustrated in each demonstration are…

  3. The Adverse Effects of Le Chatelier's Principle on Teacher Understanding of Chemical Equilibrium

    ERIC Educational Resources Information Center

    Cheung, Derek

    2009-01-01

    Although the scientific inadequacy of Le Chatelier's principle has long been documented in the literature, the principle is still treated as a central concept of chemical equilibrium by textbook writers and teachers in many countries. In the past, researchers' interest has focused on student misconceptions about chemical equilibrium and has…

  4. The Kalina cycle and similar cycles for geothermal power production

    SciTech Connect

    Bliem, C.J.

    1988-09-01

    This report contains a brief discussion of the mechanics of the Kalina cycle and ideas to extend the concept to other somewhat different cycles. A modified cycle which has a potential heat rejection advantage but little or no performance improvement is discussed. Then, the results of the application of the Kalina cycle and the modified cycle to a geothermal application (360/degree/F resource) are discussed. The results are compared with published results for the Kalina cycle with high temperature sources and estimates about performance at the geothermal temperatures. Finally, the conclusions of this scoping work are given along with recommendations of the direction of future work in this area. 11 refs., 4 figs., 1 tab.

  5. Concept Mapping.

    ERIC Educational Resources Information Center

    Callison, Daniel

    2001-01-01

    Explains concept mapping as a heuristic device that is helpful in visualizing the relationships between and among ideas. Highlights include how to begin a map; brainstorming; map applications, including document or information summaries and writing composition; and mind mapping to strengthen note-taking. (LRW)

  6. Cycle Analysis

    Energy Science and Technology Software Center (ESTSC)

    2012-03-20

    1. The Cycle Analysis code is an Microsoft Excel code that performs many different types of thermodynamic cycle analysis for power producing systems. The code will calculate the temperature and pressure and all other thermodynamic properties at the inlet and outlet of each component. The code also calculates the power that is produced, the efficiency, and the heat transported in the heater, gas chiller and recuperators. The code provides a schematic of the loop andmore » provides the temperature and pressure at each location in the loop. The code also provides a T-S (temperature-entropy) diagram of the loop and often it provides an pressure enthalpy plot as well. 2. This version of the code concentrates on supercritical CO2 power cycles, but by simply changing the name of the working fluid many other types of fluids can be analyzed. The Cycle Analysis code provided here contains 18 different types of power cycles. Each cycle is contained in one worksheet or tab that the user can select. The user can change the yellow highlighted regions to perform different thermodynamic cycle analysis.« less

  7. Portevin-Le chatelier effect

    PubMed

    Franklin; Mertens; Marder

    2000-12-01

    Aluminum subjected to smooth mechanical loading does not often deform in a correspondingly smooth manner. Typically it deforms inhomogeneously through the propagation of deformation fronts that slowly traverse the sample. These are called Portevin-Le Chatelier fronts; what determines their velocity has been somewhat mysterious. We present a phenomenological theory for deformation fronts that centers on a nonlocal rate dependence of the flow stress. In a one-dimensional idealization the equations can be solved exactly, and compared directly with experiment. Many significant features of deformation fronts are captured, including a well-known transition from hopping to continuous front motion. The phenomenology's predictions are confirmed by our experiments. PMID:11138118

  8. TQM: the essential concepts.

    PubMed

    Chambers, D W

    1998-01-01

    This is an introduction to the major concepts in total quality management, a loose collection of management approaches that focus on continuous improvement of processes, guided by routine data collection and adjustment of the processes. Customer focus and involvement of all members of an organization are also characteristics commonly found in TQM. The seventy-five-year history of the movement is sketched from its beginning in statistical work on quality assurance through the many improvements and redefinitions added by American and Japanese thinkers. Essential concepts covered include: control cycles, focus on the process rather than the defects, the GEAR model, importance of the customer, upstream quality, just-in-time, kaizen, and service quality. PMID:9697367

  9. Cycling injuries.

    PubMed Central

    Cohen, G. C.

    1993-01-01

    Bicycle-related injuries have increased as cycling has become more popular. Most injuries to recreational riders are associated with overuse or improper fit of the bicycle. Injuries to racers often result from high speeds, which predispose riders to muscle strains, collisions, and falls. Cyclists contact bicycles at the pedals, seat, and handlebars. Each is associated with particular cycling injuries. Images Figure 1 Figure 3 Figure 4 Figure 5 PMID:8471908

  10. Nutrient cycling.

    PubMed

    Bormann, F H; Likens, G E

    1967-01-27

    The small-watershed approach to problems of nutrient cycling has these advantages. (i) The small watershed is a natural unit of suitable size for intensive study of nutrient cycling at the ecosystem level. (ii) It provides a means of reducing to a minimum, or virtually eliminating, the effect of the difficult-to-measure variables of geologic input and nutrient losses in deep seepage. Control of these variables makes possible accurate measurement of nutrient input and output (erosion) and therefore establishes the relationship of the smaller ecosystem to the larger biospheric cycles. (iii) The small-watershed approach provides a method whereby such important parameters as nutrient release from minerals (weathering) and annual nutrient budgets may be calculated. (iv) It provides a means of studying the interrelationships between the biota and the hydrologic cycle, various nutrient cycles, and energy flow in a single system. (v) Finally, with the small-watershed system we can test the effect of various land-management practices or environmental pollutants on nutrient cycling in natural systems. PMID:17737551

  11. Lele de métrologie de SOLEIL

    NASA Astrophysics Data System (ADS)

    Idir, M.; Brochet, S.; Delmotte, A.; Lagarde, B.; Mercere, P.; Moreno, T.; Polack, F.; Thomasset, M.

    2006-12-01

    Lele de METROLOGIE de SOLEIL a pour objet de créer sur le synchrotron SOLEIL, une plateforme constituée : - une ligne de lumière utilisant le rayonnement synchrotron (métrologie dite à la longueur d'onde) - d'un laboratoire de métrologie associé (métrologie dite ll classique gg ) Ces deux types de Métrologie sont l'une et l'autre indispensables pour soutenir l'activité de recherche instrumentale en optique X et X-UV. Ce projet de pôle de METROLOGIE ne répondra pas seulement aux besoins des groupes chargés de l'équipement du synchrotron SOLEIL en optiques et détecteurs mais aussi pour préparer, tester et mettre au point les postes expérimentaux, ce qui concerne déjà une large communauté d'utilisateurs. Il sera aussi largement ouvert, dès sa mise en service, à l'ensemble de la communauté scientifique concernée par l'instrumentation X et XUV en Ile de France, en France, voire même en Europe si la demande continue de croître plus vite que l'offre dans ce domaine. Ligne de lumière Métrologie à la longueur d'onde La ligne de lumière sera équipée de plusieurs stations permettant de mesurer, dans la plus grande partie du spectre couvert par le synchrotron, les paramètres photométriques qui caractérisent les éléments optiques, tels que : la réflectivité de surfaces, l'efficacité de diffraction des réseaux, la diffusion des surfaces ou l'efficacité des détecteurs X et X-UV et la calibration absolue. Cette installation pourra servir également à développer des instruments et des diagnostics nécessaires à la caractérisation des faisceaux de rayons X (intensité, taille, degré de cohérence, polarisation etc.) Métrologie Classique La métrologie des surfaces optiques est devenue une nécessité critique pour les laboratoires et les industries qui utilisent les photons X et X-UV (synchrotrons, centres laser, etc. .). En effet, les progrès de calcul et de conception des systèmes optiques pour ces longueurs d'onde (optiques

  12. L'astronomie dans le monde

    NASA Astrophysics Data System (ADS)

    Manfroid, J.

    2008-09-01

    Fragmentation et astéroïdes binaires; Astéroïde géocroiseur triple; Rosetta sort de son hibernation; Messenger; Transit lunaire vu par Deep Impact; Titan; Phobos; Phoenix; Einstein avait raison; Le ballet des taches rouges; Le poids des lentilles;

  13. Vapor Compression Cycle Design Program (CYCLE_D)

    National Institute of Standards and Technology Data Gateway

    SRD 49 NIST Vapor Compression Cycle Design Program (CYCLE_D) (PC database for purchase)   The CYCLE_D database package simulates the vapor compression refrigeration cycles. It is fully compatible with REFPROP 9.0 and covers the 62 single-compound refrigerants . Fluids can be used in mixtures comprising up to five components.

  14. Difficult Concepts

    NASA Astrophysics Data System (ADS)

    Fosbury, R.

    2005-12-01

    Beautiful colour images of the sky are both a blessing and a curse for the communication of astronomy to the public. While undoubtedly attractive, they can obscure the fact that discoveries are often made in astrophysics using techniques and measurements that are much more difficult to grasp and certainly less appealing to view. Should we try to explain such concepts as spectroscopy, polarimetry and interferometry, or is it a lost cause? The most effective approach to this problem may be to lead the audience to ask the question themselves: "But how do you know that?"

  15. Le syndrome d'apert

    PubMed Central

    Benmiloud, Sarra; Chaouki, Sana; Atmani, Samir; Hida, Moustapha

    2013-01-01

    Le syndrome d'Apert est une affection congénitale rare, caractérisée par une sténose cranio-faciale associée à une syndactylie des mains et des pieds. Sa prise en charge doit être précoce et multidisciplinaire. Sa gravité réside dans la coexistence de plusieurs malformations avec un risque d'hypertension intracrânienne chronique responsable d'une cécité et d'une débilité mentale. Les auteurs rapportent une nouvelle observation à travers laquelle ils illustrent les aspects cliniques et évolutifs ainsi que les difficultés thérapeutiques de cette affection. PMID:23565313

  16. Intraday LeBaron effects

    PubMed Central

    Bianco, Simone; Corsi, Fulvio; Renò, Roberto

    2009-01-01

    We study the relation at intraday level between serial correlation and volatility of the Standard and Poor (S&P) 500 stock index futures returns. At daily and weekly levels, serial correlation and volatility forecasts have been found to be negatively correlated (LeBaron effect). After finding a significant attenuation of the original effect over time, we show that a similar but more pronounced effect holds by using intraday measures, by such as realized volatility and variance ratio. We also test the impact of unexpected volatility, defined as the part of volatility which cannot be forecasted, on the presence of intraday serial correlation in the time series by employing a model for realized volatility based on the heterogeneous market hypothesis. We find that intraday serial correlation is negatively correlated to volatility forecasts, whereas it is positively correlated to unexpected volatility.

  17. Heat Cycle Reserch Experimental Program report, FY-84

    SciTech Connect

    Whitbeck, J.F.

    1984-09-01

    The Heat Cycle Research Facility (HCRF) is an experimental binary-cycle facility used to investigate different concepts and/or components for generating electrical power from a geothermal resource. This report briefly desc

  18. Menu Cycles.

    ERIC Educational Resources Information Center

    Clayton, Alfred; Almony, John

    The curriculum guide for commercial foods instruction is designed to aid the teacher in communicating the importance of menu cycles in commercial food production. It also provides information about the necessary steps in getting food from the raw form to the finished product, and then to the consumer. In addition to providing information on how to…

  19. Fundamental Cycles of Cognitive Growth.

    ERIC Educational Resources Information Center

    Pegg, John

    Over recent years, various theories have arisen to explain and predict cognitive development in mathematics education. We focus on an underlying theme that recurs throughout such theories: a fundamental cycle of growth in the learning of specific concepts, which we frame within broader global theories of individual cognitive growth. Our purpose is…

  20. Autoradiography and the Cell Cycle.

    ERIC Educational Resources Information Center

    Jones, C. Weldon

    1992-01-01

    Outlines the stages of a cell biology "pulse-chase" experiment in which the students apply autoradiography techniques to learn about the concept of the cell cycle. Includes (1) seed germination and plant growth; (2) radioactive labeling and fixation of root tips; (3) feulgen staining of root tips; (4) preparation of autoradiograms; and (5)…

  1. Creative Writing and the Water Cycle.

    ERIC Educational Resources Information Center

    Young, Rich; Virmani, Jyotika; Kusek, Kristen M.

    2001-01-01

    Uses the story "The Life of a Drop of Water" to initiate a creative writing activity and teach about the water cycle. Attempts to stimulate students' understanding of a scientific concept by using their imaginations. (YDS)

  2. Aristides Leão: a birth centennial homage with comments on his spreading depression.

    PubMed

    Engelhardt, Eliasz; Gomes, Marleide da Mota

    2015-06-01

    The year of 2014 is the birth centenary of Aristides Azevedo Pacheco Leão (1914-1993), and also marks seventy years of the publication of his discovery of the novel electrophysiological phenomenon, named by him "spreading depression" (SD), soon designated "Leão's wave" or "Leão's spreading depression". This was a remarkable scientific milestone, and the author must be celebrated for this achievement, as the studies he triggered proceeded worldwide, with new concepts, as spreading depolarization, until the present days. Robust experimental and clinical evidence emerged to suggest that these and related electrophysiological phenomena are involved in the mechanisms of migraine aura, acute cerebrovascular diseases, traumatic brain injury, transient global amnesia, epileptic seizures, and their pathophysiological characteristics come to offer new therapeutic perspectives. He was a remarkable and complex personality, and the authors remit the readers to a paper where his personal life is contemplated. PMID:26083892

  3. Prometheus Hot Leg Piping Concept

    SciTech Connect

    Gribik, Anastasia M.; DiLorenzo, Peter A.

    2007-01-30

    The Naval Reactors Prime Contractor Team (NRPCT) recommended the development of a gas cooled reactor directly coupled to a Brayton energy conversion system as the Space Nuclear Power Plant (SNPP) for NASA's Project Prometheus. The section of piping between the reactor outlet and turbine inlet, designated as the hot leg piping, required unique design features to allow the use of a nickel superalloy rather than a refractory metal as the pressure boundary. The NRPCT evaluated a variety of hot leg piping concepts for performance relative to SNPP system parameters, manufacturability, material considerations, and comparison to past high temperature gas reactor (HTGR) practice. Manufacturability challenges and the impact of pressure drop and turbine entrance temperature reduction on cycle efficiency were discriminators between the piping concepts. This paper summarizes the NRPCT hot leg piping evaluation, presents the concept recommended, and summarizes developmental issues for the recommended concept.

  4. A hybrid Brayton engine concept

    NASA Technical Reports Server (NTRS)

    Six, L. D.; Elkins, R.

    1980-01-01

    A first generation open cycle Brayton engine concept for use in full scale solar module testing was defined. The concept extended to include solar/fossil hybrid capability. The combustion system defined for hybrid operation consists of a wide range combustor liner, a single airblast atomizer, an ignitor and a high-voltage ignition unit. Wide range combustor operation would be achieved through combining pilot and primary zones. The hybrid control mode and the solar only control mode are both based on the concept of maintaining constant turbine inlet temperature and varying the engine speed for part-power operation. In addition, the hybrid control concept will allow the operator to set a minimum thermal power input to the engine by setting a corresponding minimum engine speed. When the solar thermal power input falls below this minimum, fossil fuel would be utilized to augment the solar thermal power input.

  5. Prometheus Hot Leg Piping Concept

    NASA Astrophysics Data System (ADS)

    Gribik, Anastasia M.; DiLorenzo, Peter A.

    2007-01-01

    The Naval Reactors Prime Contractor Team (NRPCT) recommended the development of a gas cooled reactor directly coupled to a Brayton energy conversion system as the Space Nuclear Power Plant (SNPP) for NASA's Project Prometheus. The section of piping between the reactor outlet and turbine inlet, designated as the hot leg piping, required unique design features to allow the use of a nickel superalloy rather than a refractory metal as the pressure boundary. The NRPCT evaluated a variety of hot leg piping concepts for performance relative to SNPP system parameters, manufacturability, material considerations, and comparison to past high temperature gas reactor (HTGR) practice. Manufacturability challenges and the impact of pressure drop and turbine entrance temperature reduction on cycle efficiency were discriminators between the piping concepts. This paper summarizes the NRPCT hot leg piping evaluation, presents the concept recommended, and summarizes developmental issues for the recommended concept.

  6. Promethus Hot Leg Piping Concept

    SciTech Connect

    AM Girbik; PA Dilorenzo

    2006-01-24

    The Naval Reactors Prime Contractor Team (NRPCT) recommended the development of a gas cooled reactor directly coupled to a Brayton energy conversion system as the Space Nuclear Power Plant (SNPP) for NASA's Project Prometheus. The section of piping between the reactor outlet and turbine inlet, designated as the hot leg piping, required unique design features to allow the use of a nickel superalloy rather than a refractory metal as the pressure boundary. The NRPCT evaluated a variety of hot leg piping concepts for performance relative to SNPP system parameters, manufacturability, material considerations, and comparison to past high temperature gas reactor (HTGR) practice. Manufacturability challenges and the impact of pressure drop and turbine entrance temperature reduction on cycle efficiency were discriminators between the piping concepts. This paper summarizes the NRPCT hot leg piping evaluation, presents the concept recommended, and summarizes developmental issues for the recommended concept.

  7. Concept Mapping

    PubMed Central

    Brennan, Laura K.; Brownson, Ross C.; Kelly, Cheryl; Ivey, Melissa K.; Leviton, Laura C.

    2016-01-01

    Background From 2003 to 2008, 25 cross-sector, multidisciplinary community partnerships funded through the Active Living by Design (ALbD) national program designed, planned, and implemented policy and environmental changes, with complementary programs and promotions. This paper describes the use of concept-mapping methods to gain insights into promising active living intervention strategies based on the collective experience of community representatives implementing ALbD initiatives. Methods Using Concept Systems software, community representatives (n=43) anonymously generated actions and changes in their communities to support active living (183 original statements, 79 condensed statements). Next, respondents (n=26, from 23 partnerships) sorted the 79 statements into self-created categories, or active living intervention approaches. Respondents then rated statements based on their perceptions of the most important strategies for creating community changes (n=25, from 22 partnerships) and increasing community rates of physical activity (n=23, from 20 partnerships). Cluster analysis and multidimensional scaling were used to describe data patterns. Results ALbD community partnerships identified three active living intervention approaches with the greatest perceived importance to create community change and increase population levels of physical activity: changes to the built and natural environment, partnership and collaboration efforts, and land-use and transportation policies. The relative importance of intervention approaches varied according to subgroups of partnerships working with different populations. Conclusions Decision makers, practitioners, and community residents can incorporate what has been learned from the 25 community partnerships to prioritize active living policy, physical project, promotional, and programmatic strategies for work in different populations and settings. PMID:23079266

  8. LeSTIG1, an extracellular binding partner for the pollen receptor kinases LePRK1 and LePRK2, promotes pollen tube growth in vitro.

    PubMed

    Tang, Weihua; Kelley, Dior; Ezcurra, Inés; Cotter, Robyn; McCormick, Sheila

    2004-08-01

    As pollen tubes grow through the pistil they are thought to perceive and respond to diverse signals. The tomato pollen-specific receptor kinases LePRK1 and LePRK2 might participate in signaling during pollen tube growth. We previously showed that the extracellular domain of LePRK2 interacts with a pollen protein, LAT52, before but not after pollen germination. To determine whether LePRK2 might have different binding partner(s) after pollen germination, we characterized two more proteins that, like LAT52, were identified in yeast two-hybrid screens using the extracellular domains of LePRK1 and LePRK2 as baits. We show that LeSHY, a leucine-rich repeat protein from pollen, and LeSTIG1, a small cysteine-rich protein from pistil, can bind the extracellular domains of both LePRK1 and LePRK2 in vitro. In vitro binding assays with the extracellular domain of LePRK2 suggested that LeSTIG1 could displace binding of LAT52, consistent with the idea that LePRK1 and LePRK2 might interact with different ligands at different stages of pollen tube growth. Exogenous LeSTIG1 promotes pollen tube growth in vitro. The interaction of these pollen kinases with LeSTIG1 supports the notion that LePRK1 and LePRK2 are involved in mediating pollen-pistil interactions. PMID:15255864

  9. Jan Potocki et le "Gothic Novel"

    ERIC Educational Resources Information Center

    Finne, Jacques

    1970-01-01

    Establishes a parallel between the supernatural and fantastic qualities of Le Comte Jan Potocki's literary works, and the English gothic novels by comparing the elements of terror, mysterious atmosphere, and the supernatural beings involved. (DS)

  10. Technium concept

    NASA Astrophysics Data System (ADS)

    Clement, Marc; Davies, Stephen

    2002-05-01

    Traditionally the economy of Wales has been based on the coal and steel industries. Recently, Wales has elected its own National Assembly and together with the Welsh Development Agency (WDA) and through a Regional Technology Plan, has prioritized the creation and development of a knowledge based economy. The culture of Wales has always placed emphasis on education and for a small nation, has a University sector with an excellent reputation for advanced research. The WDA and the University of Wales Swansea came together to establish Technium, which is an unique concept designed to bridge the gap between advanced University research and commercial exploitation. Technium was co-funded by the WDA and the European Regional Development Fund. The project is seen as the first phase of creating a network of sector specific Techniums across the country, all linked via state of the art telecomm-infrastructure to University centers of research excellence. This paper will describe two case studies, both in the Optics/Photonics field, of research centers being established in Technium by blue chip international companies. Those companies having located in Technium specifically because of the links to high quality university research. One company is Agilent Technologies Inc., USA) a global leader in Optoelectronic components. The second company, ICN Pharmaceuticals Inc, design and develop optical devices to be used in conjunction with pharmaceuticals for the treatment of a range of diseases. Working closely with the WDA and the University of Wales Swansea, these and other companies will pursue product development, sponsor postgraduate research and generate intellectual capital that will benefit the company, students and the region alike.

  11. Combined-cycle power tower

    SciTech Connect

    Bohn, M S; Williams, T A; Price, H W

    1994-10-01

    This paper evaluates a new power tower concept that offers significant benefits for commercialization of power tower technology. The concept uses a molten nitrate salt centralreceiver plant to supply heat, in the form of combustion air preheat, to a conventional combined-cycle power plant. The evaluation focused on first commercial plants, examined three plant capacities (31, 100, and 300 MWe), and compared these plants with a solar-only 100-MWe plant and with gas-only combined-cycle plants in the same three capacities. Results of the analysis point to several benefits relative to the solar-only plant including low energy cost for first plants, low capital cost for first plants, reduced risk with respect to business uncertainties, and the potential for new markets. In addition, the concept appears to have minimal technology development requirements. Significantly, the results show that it is possible to build a first plant with this concept that can compete with existing gas-only combined-cycle plants.

  12. Identification and Analysis of Student Conceptions Used To Solve Chemical Equilibrium Problems.

    ERIC Educational Resources Information Center

    Voska, Kirk W.; Heikkinen, Henry W.

    2000-01-01

    Identifies and quantifies the chemistry conceptions used by students when solving chemical equilibrium problems requiring application of LeChatelier's Principle, and explores the feasibility of designing a paper and pencil test to accomplish these purposes. Eleven prevalent incorrect student conceptions about chemical equilibrium were identified…

  13. Rocketdyne RBCC Concept Development

    NASA Technical Reports Server (NTRS)

    Ortwerth, P.; Ratekin, G.; Goldman, A.; Emanuel, M.; Brown, C.; Ketchum, A.; Horn, M.

    1997-01-01

    Rocketdyne is pursuing the conceptual design and development of a Rocket Based Combined Cycle (BBCC) engine for booster and SSTO, advanced reusable space transportation systems under the Advanced Reusable Transportation Technologies contract with NASA Marshall Space Flight Center. The Rocketdyne concept is a fixed geometry integrated rocket, ramjet, scramjet which is hydrogen fueled and uses hydrogen regenerative cooling. Vision vehicle integration studies have determined that scramjet operation to the range of Mach 10 to 12 has high payoff for low cost reusable space transportation. Rocketdyne is internally developing versions of the concept for other applications in high speed aircraft and missiles with hydrocarbon fuel systems. A subscale engine ground test program is underway for all modes of operation from takeoff to Mach 8. High altitude rocket tests will only be completed as part of the ground test program to validate high expansion ratio performance. A unique feature of the ground test series is the inclusion of dynamic trajectory simulation with real time Mach number, altitude, engine throttling, and RBCC mode changes in a specially modified freejet test facility at GASL. Preliminary cold flow air augmented rocket and all rocket test results have met program goals and have been used to integrate all modes of operation in a single combustor design with a fixed geometry inlet for design confirmation tests. A water cooled subscale engine is currently being fabricated for test during the early part of 1998.

  14. AXTAR: Mission Design Concept

    NASA Technical Reports Server (NTRS)

    Ray, Paul S.; Chakrabarty, Deepto; Wilson-Hodge, Colleen A.; Philips, Bernard F.; Remillard, Ronald A.; Levine, Alan M.; Wood, Kent S.; Wolff, Michael T.; Gwon, Chul S.; Strohmayer, Tod E.; Briggs, Michael S.; Capizzo, Peter; Fabisinski, Leo; Hopkins, Randall C.; Hornsby, Linda S.; Johnson, Les; Maples, C. Dauphne; Miernik, Janie H.; Thomas, Dan; DeGeronimo, Gianluigi

    2010-01-01

    The Advanced X-ray Timing Array (AXTAR) is a mission concept for X-ray timing of compact objects that combines very large collecting area, broadband spectral coverage, high time resolution, highly flexible scheduling, and an ability to respond promptly to time-critical targets of opportunity. It is optimized for sub-millisecond timing of bright Galactic X-ray sources in order to study phenomena at the natural time scales of neutron star surfaces and black hole event horizons, thus probing the physics of ultra-dense matter, strongly curved spacetimes, and intense magnetic fields. AXTAR s main instrument, the Large Area Timing Array (LATA) is a collimated instrument with 2 50 keV coverage and over 3 square meters effective area. The LATA is made up of an array of super-modules that house 2-mm thick silicon pixel detectors. AXTAR will provide a significant improvement in effective area (a factor of 7 at 4 keV and a factor of 36 at 30 keV) over the RXTE PCA. AXTAR will also carry a sensitive Sky Monitor (SM) that acts as a trigger for pointed observations of X-ray transients in addition to providing high duty cycle monitoring of the X-ray sky. We review the science goals and technical concept for AXTAR and present results from a preliminary mission design study

  15. Entrevue avec le Dr Charley Zeanah

    PubMed Central

    2013-01-01

    Le Dr Charles Zeanah est titulaire de la chaire de psychiatrie Mary K. Sellars-Polchow, professeur de pédiatrie clinique et vice-président de la pédopsychiatrie au département de psychiatrie et des sciences du comportement de la faculté de médecine de l’Université Tulane, à la Nouvelle-Orléans. Il est également directeur général de l’institut de la santé mentale des nourrissons et des jeunes enfants de Tulane. Il est récipiendaire de nombreux prix, notamment le prix de prévention Irving Phillips (AACAP), la mention élogieuse présidentielle pour sa recherche et son leadership exceptionnels en santé mentale des nourrissons (American Orthopsychiatric Association), le prix d’excellence clinique Sarah Haley Memorial (International Society for Traumatic Stress Studies), le prix de recherche en pédopsychiatrie Blanche F. Ittelson (APA), et le prix Serge Lebovici Award soulignant les contributions internationales à la santé mentale des nourrissons (World Association for Infant Mental Health). Le Dr Zeanah est fellow distingué de l’AACAP, fellow distingué de l’APA et membre du conseil d’administration de Zero to Three. Il est l’éditeur scientifique de Handbook of Infant Mental Health (3e édition) qui est considéré comme étant le manuel de pointe et la référence de base du domaine de la santé mentale des nourrissons.

  16. Radioisotope Power System Pool Concept

    NASA Technical Reports Server (NTRS)

    Rusick, Jeffrey J.; Bolotin, Gary S.

    2015-01-01

    Advanced Radioisotope Power Systems (RPS) for NASA deep space science missions have historically used static thermoelectric-based designs because they are highly reliable, and their radioisotope heat sources can be passively cooled throughout the mission life cycle. Recently, a significant effort to develop a dynamic RPS, the Advanced Stirling Radioisotope Generator (ASRG), was conducted by NASA and the Department of Energy, because Stirling based designs offer energy conversion efficiencies four times higher than heritage thermoelectric designs; and the efficiency would proportionately reduce the amount of radioisotope fuel needed for the same power output. However, the long term reliability of a Stirling based design is a concern compared to thermoelectric designs, because for certain Stirling system architectures the radioisotope heat sources must be actively cooled via the dynamic operation of Stirling converters throughout the mission life cycle. To address this reliability concern, a new dynamic Stirling cycle RPS architecture is proposed called the RPS Pool Concept.

  17. Variable cycle engines for advanced supersonic transports

    NASA Technical Reports Server (NTRS)

    Howlett, R. A.; Kozlowski, H.

    1975-01-01

    Variable Cycle Engines being studied for advanced commercial supersonic transports show potential for significant environmental and economic improvements relative to 1st generation SST engines. The two most promising concepts are: a Variable Stream Control Engine and a Variable Cycle Engine with a rear flow-control valve. Each concept utilizes variable components and separate burners to provide independent temperature and velocity control for two coannular flow streams. Unique fuel control techniques are combined with cycle characteristics that provide low fuel consumption, similar to a turbojet engine, for supersonic operation. This is accomplished while retaining the good subsonic performance features of a turbofan engine. A two-stream coannular nozzle shows potential to reduce jet noise to below FAR Part 36 without suppressors. Advanced burner concepts have the potential for significant reductions in exhaust emissions. In total, these unique engine concepts have the potential for significant overall improvements to the environmental and economic characteristics of advanced supersonic transports.

  18. Family Development and the Family Life Cycle: An Empirical Evaluation.

    ERIC Educational Resources Information Center

    Spanier, Graham; And Others

    The concept of family life cycle has become increasingly prominent in the study of family development--the formation, maintenance, change, and dissolution of marriage and family relations. An evaluation of this concept is accomplished by examining the relationships between three possible stratification schemes: stage of the family life cycle,…

  19. Advanced Nuclear Fuel Cycle Options

    SciTech Connect

    Roald Wigeland; Temitope Taiwo; Michael Todosow; William Halsey; Jess Gehin

    2010-06-01

    A systematic evaluation has been conducted of the potential for advanced nuclear fuel cycle strategies and options to address the issues ascribed to the use of nuclear power. Issues included nuclear waste management, proliferation risk, safety, security, economics and affordability, and sustainability. The two basic strategies, once-through and recycle, and the range of possibilities within each strategy, are considered for all aspects of the fuel cycle including options for nuclear material irradiation, separations if needed, and disposal. Options range from incremental changes to today’s implementation to revolutionary concepts that would require the development of advanced nuclear technologies.

  20. Your Menstrual Cycle

    MedlinePlus

    ... during your menstrual cycle What happens during your menstrual cycle The menstrual cycle includes not just your period, but the rise ... tool is based on a sample 28-day menstrual cycle, but every woman is different in how long ...

  1. L'astronomie dans le monde

    NASA Astrophysics Data System (ADS)

    Manfroid, J.

    2014-06-01

    Future lune ? - L'âge de la Lune - Des volcans actifs sur Vénus - Un lac dans le cratère Gusev ? - Météorites et atmosphère martiennes - L’hexagone de Saturne - Pluton - Exo-Terre - Bêta Pictoris b - Cérès et Vesta depuis Mars - Naine froide - Parallaxes par Hubble - L2 Puppis et le sort du Soleil - Supernova et lentille gravitationnelle - Champ magnétique galactique - L’objet de Sakurai - Fermi et la matière noire - Lentille naine

  2. Open cycle thermoacoustics

    SciTech Connect

    Reid, Robert Stowers

    2000-01-01

    A new type of thermodynamic device combining a thermodynamic cycle with the externally applied steady flow of an open thermodynamic process is discussed and experimentally demonstrated. The gas flowing through this device can be heated or cooled in a series of semi-open cyclic steps. The combination of open and cyclic flows makes possible the elimination of some or all of the heat exchangers (with their associated irreversibility). Heat is directly exchanged with the process fluid as it flows through the device when operating as a refrigerator, producing a staging effect that tends to increase First Law thermodynamic efficiency. An open-flow thermoacoustic refrigerator was built to demonstrate this concept. Several approaches are presented that describe the physical characteristics of this device. Tests have been conducted on this refrigerator with good agreement with a proposed theory.

  3. Coal combined cycle system study. Volume I. Summary

    SciTech Connect

    Not Available

    1980-04-01

    The potential advantages for proceeding with demonstration of coal-fueled combined cycle power plants through retrofit of a few existing utility steam plants have been evaluated. Two combined cycle concepts were considered: Pressurized Fluidized Bed (PFB) combined cycle and gasification combined cycle. These concepts were compared with AFB steam plants, conventional steam plants with Flue Gas Desulfurization (FGD), and refueling such as with coal-oil mixtures. The ultimate targets are both new plants and conversion of existing plants. Combined cycle plants were found to be most competitive with conventional coal plants and offered lower air emissions and less adverse environmental impact. A demonstration is a necessary step toward commercialization.

  4. Auditing Hierarchical Cycles to Locate Other Inconsistencies in the UMLS

    PubMed Central

    Halper, Michael; Morrey, C. Paul; Chen, Yan; Elhanan, Gai; Hripcsak, George; Perl, Yehoshua

    2011-01-01

    A cycle in the parent relationship hierarchy of the UMLS is a configuration that effectively makes some concept(s) an ancestor of itself. Such a structural inconsistency can easily be found automatically. A previous strategy for disconnecting cycles is to break them with the deletion of one or more parent relationships—irrespective of the correctness of the deleted relationships. A methodology is introduced for auditing of cycles that seeks to discover and delete erroneous relationships only. Cycles involving three concepts are the primary consideration. Hypotheses about the high probability of locating an erroneous parent relationship in a cycle are proposed and confirmed with statistical confidence and lend credence to the auditing approach. A cycle may serve as an indicator of other non-structural inconsistencies that are otherwise difficult to detect automatically. An extensive auditing example shows how a cycle can indicate further inconsistencies. PMID:22195107

  5. Development of a Clerkship Curriculum in the Family Life Cycle.

    ERIC Educational Resources Information Center

    Armstrong, Elizabeth G.; And Others

    1982-01-01

    A course is described that focuses on concepts and dynamics of family life cycle relating to medical practice, including the relationship of cycle stages to onset, development, and treatment of illness, transition points in the cycle, the role of stress, and the risk for illness among family members. (Author/MSE)

  6. Plant cycle chemistry during startup and shutdown and during cycling and peaking operation

    SciTech Connect

    Seipp, H.G.; Kloeckl, W.; Bursik, A.; Hajdamowicz, S.; Pflug, H.; Pieper, B.

    1995-01-01

    This paper presents some preliminary results of a VGB Subcommittee working on the preparation of VGB Guidelines for startup and shutdown and cycling and peaking operation. The main points are listed below: behavior of protective layers in steam generators; impurities transport; impact of different plant concepts and plant cycle chemistry treatments; recommended startup procedure for a unit operated on OT; and data acquisition and evaluation during startup, shutdown and cycling and peaking operation.

  7. Advanced General Aviation Turbine Engine (GATE) concepts

    NASA Technical Reports Server (NTRS)

    Lays, E. J.; Murray, G. L.

    1979-01-01

    Concepts are discussed that project turbine engine cost savings through use of geometrically constrained components designed for low rotational speeds and low stress to permit manufacturing economies. Aerodynamic development of geometrically constrained components is recommended to maximize component efficiency. Conceptual engines, airplane applications, airplane performance, engine cost, and engine-related life cycle costs are presented. The powerplants proposed offer encouragement with respect to fuel efficiency and life cycle costs, and make possible remarkable airplane performance gains.

  8. SCIENCE BRIEF: ADVANCED CONCEPTS

    EPA Science Inventory

    Research on advanced concepts will evaluate and demonstrate the application of innovative infrastructure designs, management procedures and operational approaches. Advanced concepts go beyond simple asset management. The infusion of these advanced concepts into established wastew...

  9. 23. VIEW OF LE CLAIRE LOCK (19211925), SHOWING OPERATING MACHINERY, ...

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

    23. VIEW OF LE CLAIRE LOCK (1921-1925), SHOWING OPERATING MACHINERY, DOWSTREAM GATES, UPSTREAM SIDE - Mississippi River 9-Foot Channel, Lock & Dam No. 14, Upper Mississippi River, Le Claire, Scott County, IA

  10. 20. VIEW OF LE CLAIRE LOCK (19211925), SHOWING UPSTREAM GATES, ...

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

    20. VIEW OF LE CLAIRE LOCK (1921-1925), SHOWING UPSTREAM GATES, DOWNSTREAM SIDE AND SOUTH LOCKWALL - Mississippi River 9-Foot Channel, Lock & Dam No. 14, Upper Mississippi River, Le Claire, Scott County, IA

  11. 30. INTERIOR VIEW OF MISSISSIPPI RIVER RECREATION OFFICE, LE CLAIRE ...

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

    30. INTERIOR VIEW OF MISSISSIPPI RIVER RECREATION OFFICE, LE CLAIRE BASE COMPOUND, LOOKING EAST - Mississippi River 9-Foot Channel, Lock & Dam No. 14, Upper Mississippi River, Le Claire, Scott County, IA

  12. 29. INTERIOR VIEW OF MISSISSIPPI RIVER RECREATION OFFICE BUILDING, LE ...

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

    29. INTERIOR VIEW OF MISSISSIPPI RIVER RECREATION OFFICE BUILDING, LE CLAIRE BASE COMPOUND, LOOKING WEST - Mississippi River 9-Foot Channel, Lock & Dam No. 14, Upper Mississippi River, Le Claire, Scott County, IA

  13. ALMA Cycle 0 Publication Statistics

    NASA Astrophysics Data System (ADS)

    Stoehr, F.; Grothkopf, U.; Meakins, S.; Bishop, M.; Uchida, A.; Testi, L.; Iono, D.; Tatematsu, K.; Wootten, A.

    2015-12-01

    The scientific impact of a facility is the most important measure of its success. Monitoring and analysing the scientific return can help to modify and optimise operations and adapt to the changing needs of scientific research. The methodology that we have developed to monitor the scientific productivity of the ALMA Observatory, as well as the first results, are described. We focus on the outcome of the first cycle (Cycle 0) of ALMA Early Science operations. Despite the fact that only two years have passed since the completion of Cycle 0 and operations have already changed substantially, this analysis confirms the effectiveness of the underlying concepts. We find that ALMA is fulfilling its promise as a transformational facility for the observation of the Universe in the submillimetre.

  14. Developing the concept of a geostationary platform. [for communication services

    NASA Technical Reports Server (NTRS)

    Carey, W. T.; Bowman, R. M.; Stone, G. R.

    1980-01-01

    A geostationary platform concept with a proliferation of low-cost earth stations is discussed. Candidate platform concepts, servicing, life, and Orbital Transfer Vehicle (OTV) options are considered. A Life Cycle Costing model is used to select the minimum cost concept meeting program criteria. It is concluded that the geostationary platform concept is a practical and economical approach to providing expanding communication services within the limitations imposed by the available frequency spectrum and orbital arc.

  15. Le Francais Courant: Part V, French.

    ERIC Educational Resources Information Center

    Dade County Public Schools, Miami, FL.

    Instructional objectives of the Dade County Public Schools Quinmester Program in French for use with "Le Francais Courant: Part 5" focus on the development of mastery of the basic numbering system and other grammatical structures. Structures include the formation of the present tense of the irregular verbs "vouloir,""pouvoir," and "venir,"…

  16. Le Francais Moderne: Part I, French.

    ERIC Educational Resources Information Center

    Dade County Public Schools, Miami, FL.

    Instructional objectives of the Dade County Public Schools Quinmester Program in French for use with "Le Francais Moderne: Part 1" focus on the development of vocabulary and mastery of grammatical structures. The formation of the passe compose with "avoir," object pronouns, the present tense of regular "-ir" verbs, and the irregular verbs…

  17. Restart function of the LE-5 engine

    NASA Astrophysics Data System (ADS)

    Hirata, Kunio; Koyari, Yukio; Yanagawa, Koji; Katsuta, Hideaki; Taniguchi, Hirofumi; Torii, Yoshihiro

    1993-10-01

    This report presents the restart function of the LE-5 (Liquid Engine-5). The development of a de/anti-ice system and a sufficient pump precooling system was key in establishing this function. To ensure high reliability, a contingency device was also adopted. The functions were proved through actual flights.

  18. A Colorful Demonstration of Le Chbtelier's Principle.

    ERIC Educational Resources Information Center

    Last, Arthur M.; Slade, Peter W.

    1997-01-01

    Le Chbtelier's Principle states that, when a system at equilibrium is subjected to stress, the system will respond in such a way as to minimize the effect of the stress. Describes a lecture demonstration that illustrates shifts in the position of equilibrium caused by a variety of factors. The equilibrium mixture contains iron (III) and…

  19. Hydrological cycle.

    PubMed

    Gonçalves, H C; Mercante, M A; Santos, E T

    2011-04-01

    The Pantanal hydrological cycle holds an important meaning in the Alto Paraguay Basin, comprising two areas with considerably diverse conditions regarding natural and water resources: the Plateau and the Plains. From the perspective of the ecosystem function, the hydrological flow in the relationship between plateau and plains is important for the creation of reproductive and feeding niches for the regional biodiversity. In general, river declivity in the plateau is 0.6 m/km while declivity on the plains varies from 0.1 to 0.3 m/km. The environment in the plains is characteristically seasonal and is home to an exuberant and abundant diversity of species, including some animals threatened with extinction. When the flat surface meets the plains there is a diminished water flow on the riverbeds and, during the rainy season the rivers overflow their banks, flooding the lowlands. Average annual precipitation in the Basin is 1,396 mm, ranging from 800 mm to 1,600 mm, and the heaviest rainfall occurs in the plateau region. The low drainage capacity of the rivers and lakes that shape the Pantanal, coupled with the climate in the region, produce very high evaporation: approximately 60% of all the waters coming from the plateau are lost through evaporation. The Alto Paraguay Basin, including the Pantanal, while boasting an abundant availability of water resources, also has some spots with water scarcity in some sub-basins, at different times of the year. Climate conditions alone are not enough to explain the differences observed in the Paraguay River regime and some of its tributaries. The complexity of the hydrologic regime of the Paraguay River is due to the low declivity of the lands that comprise the Mato Grosso plains and plateau (50 to 30 cm/km from east to west and 3 to 1.5 cm/km from north to south) as well as the area's dimension, which remains periodically flooded with a large volume of water. PMID:21537597

  20. Conceptions of Parents, Conceptions of Self, and Conceptions of God.

    ERIC Educational Resources Information Center

    Buri, John R.; Mueller, Rebecca A.

    Different theorists have suggested that an individual's view of God may be related to one's view of one's father, one's mother, or one's self. A study was conducted to examine the relationship of college students' conceptions of the wrathfulness-kindliness of God to their conceptions of their father's and mother's permissiveness, authoritarianism,…

  1. Type-1 chain histo-blood group antigens (Le(a), monosialosyl-Le(a), disialosyl-Le(a), Le(b), and H) in normal and malignant human endometrium.

    PubMed

    Ravn, V; Mandel, U; Svenstrup, B; Dabelsteen, E

    1994-01-01

    Type-1 chain histo-blood group antigens such as the Lewis (Le)a, monosialosyl-Le(a), Le(b) and H antigens show an increased expression in endometrial carcinomas. However, the possibility that these antigens are expressed under genetic or hormonal influence in endometrial carcinomas has not been considered. In the present study, the expression of type-1 chain carbohydrate antigens in normal and malignant endometrium was evaluated by immunohistochemistry and related to both genetic and hormonal factors. The glands of normal, non-secretory endometria expressed, in contrast with surface epithelial cells, Le(a), Le(b), disialosyl-Le(a), and H determinants infrequently. Adenomatous hyperplasias and endometrial carcinomas showed an increased expression of type-1 chain carbohydrates that was qualitatively influenced by the erythrocyte Lewis phenotype and the secretor status. Whereas Le(a+b-) non-secretors mainly accumulated Le(a) antigen, and only limited amounts of Le(b) antigen, Le(a-b+) secretors expressed H, Le(b) and Le(a) antigens. The expression of type-1 chain antigens showed no association with the serum-oestrogen level or to the hormone-receptor status. Thus the Lewis secretor status has a qualitative influence on the increased expression of type-1 chain antigens, which, however, seem to be unrelated to hormonal factors. Our findings suggest an increased activity of the Se-gene-defined or a closely related fucosyl-transferase in neoplastic endometrial epithelial cells. PMID:8032530

  2. Serial concept maps: tools for concept analysis.

    PubMed

    All, Anita C; Huycke, LaRae I

    2007-05-01

    Nursing theory challenges students to think abstractly and is often a difficult introduction to graduate study. Traditionally, concept analysis is useful in facilitating this abstract thinking. Concept maps are a way to visualize an individual's knowledge about a specific topic. Serial concept maps express the sequential evolution of a student's perceptions of a selected concept. Maps reveal individual differences in learning and perceptions, as well as progress in understanding the concept. Relationships are assessed and suggestions are made during serial mapping, which actively engages the students and faculty in dialogue that leads to increased understanding of the link between nursing theory and practice. Serial concept mapping lends itself well to both online and traditional classroom environments. PMID:17547345

  3. Screening analysis of solar thermochemical hydrogen concepts.

    SciTech Connect

    Diver, Richard B., Jr.; Kolb, Gregory J.

    2008-03-01

    A screening analysis was performed to identify concentrating solar power (CSP) concepts that produce hydrogen with the highest efficiency. Several CSP concepts were identified that have the potential to be much more efficient than today's low-temperature electrolysis technology. They combine a central receiver or dish with either a thermochemical cycle or high-temperature electrolyzer that operate at temperatures >600 C. The solar-to-hydrogen efficiencies of the best central receiver concepts exceed 20%, significantly better than the 14% value predicted for low-temperature electrolysis.

  4. Evaluation of the developing DSN life-cycle cost standard practice

    NASA Technical Reports Server (NTRS)

    Mckenzie, M.

    1978-01-01

    The DSN is developing a life-cycle cost standard practice by comparison to those of industry and the Department of Defense. Results show that the DSN uses the accepted concept of life-cycle costing, tailoring the concept to DSN specific needs, but does not push the concept past the point of prevailing theory.

  5. Concepts in Change

    ERIC Educational Resources Information Center

    Rusanen, Anna-Mari; Poyhonen, Samuli

    2013-01-01

    In this article we focus on the concept of concept in conceptual change. We argue that (1) theories of higher learning must often employ two different notions of concept that should not be conflated: psychological and scientific concepts. The usages for these two notions are partly distinct and thus straightforward identification between them is…

  6. Development of long operating cycle simplified BWR

    SciTech Connect

    Heki, H.; Nakamaru, M.; Maruya, T.; Hiraiwa, K.; Arai, K.; Narabayash, T.; Aritomi, M.

    2002-07-01

    This paper describes an innovative plant concept for long operating cycle simplified BWR (LSBWR) In this plant concept, 1) Long operating cycle ( 3 to 15 years), 2) Simplified systems and building, 3) Factory fabrication in module are discussed. Designing long operating core is based on medium enriched U-235 with burnable poison. Simplified systems and building are realized by using natural circulation with bottom located core, internal CRD and PCV with passive system and an integrated reactor and turbine building. This LSBWR concept will have make high degree of safety by IVR (In Vessel Retention) capability, large water inventory above the core region and no PCV vent to the environment due to PCCS (Passive Containment Cooling System) and internal vent tank. Integrated building concept could realize highly modular arrangement in hull structure (ship frame structure), ease of seismic isolation capability and high applicability of standardization and factory fabrication. (authors)

  7. Answering Key Fuel Cycle Questions

    SciTech Connect

    Piet, S.J.; Dixon, B.W.; Bennett, R.G.; Smith, J.D.; Hill, R.N.

    2004-10-03

    Given the range of fuel cycle goals and criteria, and the wide range of fuel cycle options, how can the set of options eventually be narrowed in a transparent and justifiable fashion? It is impractical to develop all options. We suggest an approach that starts by considering a range of goals for the Advanced Fuel Cycle Initiative (AFCI) and then posits seven questions, such as whether Cs and Sr isotopes should be separated from spent fuel and, if so, what should be done with them. For each question, we consider which of the goals may be relevant to eventually providing answers. The AFCI program has both ''outcome'' and ''process'' goals because it must address both waste already accumulating as well as completing the fuel cycle in connection with advanced nuclear power plant concepts. The outcome objectives are waste geologic repository capacity and cost, energy security and sustainability, proliferation resistance, fuel cycle economics, and safety. The process objectives are rea diness to proceed and adaptability and robustness in the face of uncertainties.

  8. Gravity in the Century of Light: The Gravitation Theory of Georges-Louis Le Sage

    NASA Astrophysics Data System (ADS)

    Evans, James

    2006-05-01

    Each generation of physicists, or natural philosophers, has sought to place universal gravitation in the context of its own worldview. Often this has entailed an effort to reduce gravitation to something more fundamental. But what is deemed fundamental has, of course, changed with time. Each generation attacked the problem of universal gravitation with the tools of its day and brought to bear the concepts of its own standard model. The most successful eighteenth-century attempt to provide a mechanical explanation of gravity was that of Georges-Louis Le Sage (1724-1803) of Geneva. Le Sage postulated a sea of ultramundane corpuscles, streaming in all directions and characterized by minute mass, great velocity, and complete inelasticity. Mostly these corpuscles just pass through gross bodies such as apples or planets, but a few are absorbed, leading to all the phenomena of attraction. In a voluminous correspondence with nearly all the savants of the day, Le Sage constantly reshaped his arguments for his system in order to appeal to metaphysicians, mechanicians and Newtonians of several varieties. Le Sage's theory is an especially interesting one, for several reasons. First, it serves as the prototype of a dynamical explanation of Newtonian gravity. Second, the theory came quite close to accomplishing its aim. Third, the theory had a long life and attracted comment by the leading physical thinkers of several successive generations, including Laplace, Kelvin, Maxwell and Feynman. Le Sage's theory therefore provides an excellent opportunity for the study of the evolution of attitudes toward physical explanation. The effects of national style in science and generational change take on a new clarity.

  9. Exploring a Hydrological Concept through Children's Drawings.

    ERIC Educational Resources Information Center

    Dove, J. E.; Everett, L. A.; Preece, P. F. W.

    1999-01-01

    Examines children's (n=306) drawings of a river basin to determine their understanding of scientific concepts related to the water cycle. Presents exemplars of five levels of understanding and analysis of the drawings' orientation and content. Contains 24 references. (Author/WRM)

  10. The Empathy Cycle: Refinement of a Nuclear Concept.

    ERIC Educational Resources Information Center

    Barrett-Lennard, G.T.

    1981-01-01

    Delineates a sequence of distinct stages involved in empathic interaction. There is room for considerable slippage between the inner resonation, communication, and reception levels, and measures based on data from different phases would at best be moderately associated. Principal existing (state) scales are located in reference to the model.…

  11. Solar Cycle 23: An Anomalous Cycle?

    NASA Astrophysics Data System (ADS)

    de Toma, G.; White, O. R.; Chapman, G. A.; Walton, S. R.; Preminger, D. G.; Cookson, A. M.

    2004-05-01

    We discuss the importance of solar cycle 23 as a magnetically simpler cycle and a variant from recent cycles. We see a significant decrease in sunspot activity in cycle 23 relative to cycle 22, but the strength of the total solar irradiance (TSI) cycle did not change significantly. The latest SOHO/VIRGO TSI time series is analyzed using new solar variability measures obtained from full-disk solar images made at the San Fernando Observatory and the MgII 280nm index. The TSI record for the period 1986 to the present is reproduced within about 130ppm RMS using only two indices representing photospheric and chromospheric sources of variability due to magnetic regions. This is in spite of the difference in magnetic activity between the two cycles. Our results show the continuing improvement in TSI measurements and surrogates containing information necessary to account for irradiance variability.

  12. L'astronomie dans le monde

    NASA Astrophysics Data System (ADS)

    Manfroid, J.

    2013-06-01

    Une binaire remarquable; Collision de galaxies; La nébuleuse planétaire C1295; ALMA (suite); Couple massif; Astéroïdes lointains; L’eau de Jupiter; Occultation par Pluton; Super-Terres; Première image d’une planète massive autour d’une étoile double; Tempête au pôle de Saturne

  13. Les Troubles Respiratoires Chez Le Brule

    PubMed Central

    Fassi Fihri, J.; Ezzoubi, M.; Boukind, E.H.

    2010-01-01

    Summary A travers une revue de la littérature, cet article se propose d'exposer les particularités des troubles respiratoires chez le brûlé. Ces troubles sont liés à un mécanisme direct, lorsque l'arbre respiratoire est lésé par le transfert d'énergie thermique du à la brûlure et/ou par un mécanisme indirect, lorsque la fonction respiratoire et ventilatoire du poumon est perturbée par les phénomènes loco-régionaux ou généraux du brûlé. Ces troubles respiratoires sont aggravés par l'inhalation des gaz contenus dans la fumée d'incendie. Le diagnostic de ces troubles est clinique et paraclinique. Il doit être précoce et continu. Les patients nécessitent de différents moyens thérapeutiques tels que l'oxygénothérapie, la libération des voies respiratoires, l'amélioration de la mécanique ventilatoire et de la fonction respiratoire, l'antibiothérapie ou la chirurgie des séquelles. Cette prise en charge doit nécessairement être multidisciplinaire. PMID:21991224

  14. Characterization of biological types of cattle (Cycle VII): influence of postpartum interval and estrous cycle length on fertility.

    PubMed

    Cushman, R A; Allan, M F; Thallman, R M; Cundiff, L V

    2007-09-01

    Genetic improvement in reproductive efficiency through selection is difficult because many reproductive traits are binomial and have low heritabilities. Before genetic markers can be generated for fertility in cows, greater characterization of reproductive phenotypes is needed to understand the components of the trait. The current study tested the hypotheses that: 1) breeds vary in postpartum interval to estrus (PPIE) and estrous cycle length, 2) a longer estrous cycle immediately before breeding increased pregnancy rates, and 3) a greater number of cycles before breeding increased conception rates. The postpartum interval to estrus, estrous cycle length, and number of cycles before breeding were examined in F1 cows (n = 519) obtained from mating Hereford, Angus, and MARC III cows to Hereford, Angus, Simmental, Limousin, Charolais, Gelbvieh, and Red Angus sires. Cows were classified as having 0, 1, 2, or 3 observed estrous cycles before breeding. All traits analyzed were adjusted to constant BCS. Sire breed of the cow influenced length of the PPIE and number of cycles before the start of breeding (P <0.001). Simmental-sired cows had the shortest PPIE and greatest number of cycles before breeding, whereas Limousin-sired cows had the longest PPIE and least number of cycles before breeding. Cows with a greater number of cycles before breeding did not have greater conception rates than cows that had not exhibited standing estrus before breeding (P = 0.87). In cows that cycled before breeding, the length of the estrous cycle immediately before breeding was influenced by dam breed and BCS (P <0.01). Cows out of Hereford dams had shorter estrous cycles than cows out of MARC III or Angus dams, and estrous cycle length increased as BCS increased. Conception rate decreased as length of the estrous cycle immediately before breeding increased (P = 0.05, -2.2% per d of cycle length). Therefore, previously anestrous cows were just as likely to conceive as cows that had cycled

  15. Concept Innateness, Concept Continuity, and Bootstrapping

    PubMed Central

    Carey, Susan

    2011-01-01

    The commentators raised issues relevant to all three important theses of The Origin of Concepts (TOOC). Some questioned the very existence of innate representational primitives, and others questioned my claims about their richness and whether they should be thought of as concepts. Some questioned the existence of conceptual discontinuity in the course of knowledge acquisition and others argued that discontinuity is much more common than portrayed in TOOC. Some raised issues with my characterization of Quinian bootstrapping, and others questioned the dual factor theory of concepts motivated by my picture of conceptual development. PMID:23264705

  16. Space Mission Operations Concept

    NASA Technical Reports Server (NTRS)

    Squibb, Gael F.

    1996-01-01

    This paper will discuss the concept of developing a space mission operations concept; the benefits of starting this system engineering task early; the neccessary inputs to the process; and the products that are generated.

  17. Creative Concept Mapping.

    ERIC Educational Resources Information Center

    Brown, David S.

    2002-01-01

    Recommends the use of concept mapping in science teaching and proposes that it be presented as a creative activity. Includes a sample lesson plan of a potato stamp concept mapping activity for astronomy. (DDR)

  18. Race concepts in medicine.

    PubMed

    Hardimon, Michael O

    2013-02-01

    Confusions about the place of race in medicine result in part from a failure to recognize the plurality of race concepts. Recognition that the ordinary concept of race is not identical to the racialist concept of race makes it possible to ask whether there might be a legitimate place for the deployment of concepts of race in medical contexts. Two technical race concepts are considered. The concept of social race is the concept of a social group that is taken to be a racialist race. It is apt for use in examining and addressing the medical effects of discrimination. The populationist concept of race represents race as a kind of biological population. It makes it possible to frame the question whether biological race is a factor in disease susceptibility and drug responsiveness. It is apt for use in determining whether biological race is a medically significant category. PMID:23300217

  19. ADVANCED SULFUR CONTROL CONCEPTS

    SciTech Connect

    Apostolos A. Nikolopoulos; Santosh K. Gangwal; William J. McMichael; Jeffrey W. Portzer

    2003-01-01

    Conventional sulfur removal in integrated gasification combined cycle (IGCC) power plants involves numerous steps: COS (carbonyl sulfide) hydrolysis, amine scrubbing/regeneration, Claus process, and tail-gas treatment. Advanced sulfur removal in IGCC systems involves typically the use of zinc oxide-based sorbents. The sulfides sorbent is regenerated using dilute air to produce a dilute SO{sub 2} (sulfur dioxide) tail gas. Under previous contracts the highly effective first generation Direct Sulfur Recovery Process (DSRP) for catalytic reduction of this SO{sub 2} tail gas to elemental sulfur was developed. This process is currently undergoing field-testing. In this project, advanced concepts were evaluated to reduce the number of unit operations in sulfur removal and recovery. Substantial effort was directed towards developing sorbents that could be directly regenerated to elemental sulfur in an Advanced Hot Gas Process (AHGP). Development of this process has been described in detail in Appendices A-F. RTI began the development of the Single-step Sulfur Recovery Process (SSRP) to eliminate the use of sorbents and multiple reactors in sulfur removal and recovery. This process showed promising preliminary results and thus further process development of AHGP was abandoned in favor of SSRP. The SSRP is a direct Claus process that consists of injecting SO{sub 2} directly into the quenched coal gas from a coal gasifier, and reacting the H{sub 2}S-SO{sub 2} mixture over a selective catalyst to both remove and recover sulfur in a single step. The process is conducted at gasifier pressure and 125 to 160 C. The proposed commercial embodiment of the SSRP involves a liquid phase of molten sulfur with dispersed catalyst in a slurry bubble-column reactor (SBCR).

  20. Terminology gap in hydrological cycle

    NASA Astrophysics Data System (ADS)

    Zhuo, Lu; Han, Dawei

    2016-04-01

    Water is central to life on Earth. People have been trying to understand how water moves in the hydrosphere throughout the human history. In the 9th century BC, the famous Greek poet Homer described the hydrological cycle in Iliad as "okeanos whose stream bends back in a circle" with a belief that rivers are ocean-fed from subterranean seas. Later, Aristotle (4th century BC) claimed that most of the water came from underground caverns in which air was transformed into water. It was only until 1674, French scientist Perrault developed the correct concept of the water cycle. In modern times, scientists are interested in understanding the individual processes of the hydrological cycle with a keen focus on runoff which supplies water to rivers, lakes, and oceans. Currently, the prevailing concepts on runoff processes include 'infiltration excess runoff' and 'saturation excess runoff'. However, there is no term to describe another major runoff due to the excess beyond the soil water holding capacity (i.e., the field capacity). We argue that a new term should be introduced to fill this gap, and it could be called 'holding excess runoff' which is compatible with the convention. This new term is significant in correcting a half-century misnomer where 'holding excess runoff' has been incorrectly named as 'saturation excess runoff', which was introduced by the Xinanjiang model in China in 1960s. Similar concept has been adopted in many well-known hydrological models such as PDM and HBV in which the saturation refers to the field capacity. The term 'holding excess runoff' resolves such a common confusion in the hydrological community.

  1. Solar Cycle 23: An Anomalous Cycle?

    NASA Astrophysics Data System (ADS)

    de Toma, Giuliana; White, Oran R.; Chapman, Gary A.; Walton, Stephen R.; Preminger, Dora G.; Cookson, Angela M.

    2004-07-01

    The latest SOHO VIRGO total solar irradiance (TSI) time series is analyzed using new solar variability measures obtained from full-disk solar images made at the San Fernando Observatory and the Mg II 280 nm index. We discuss the importance of solar cycle 23 as a magnetically simpler cycle and a variant from recent cycles. Our results show the continuing improvement in TSI measurements and surrogates containing information necessary to account for irradiance variability. Use of the best surrogate for irradiance variability due to photospheric features (sunspots and faculae) and chromospheric features (plages and bright network) allows fitting the TSI record to within an rms difference of 130 ppm for the period 1986 to the present. Observations show that the strength of the TSI cycle did not change significantly despite the decrease in sunspot activity in cycle 23 relative to cycle 22. This points to the difficulty of modeling TSI back to times when only sunspot observations were available.

  2. Design analysis of the Einstein refrigeration cycle

    SciTech Connect

    Shelton, S.V.; Delano, A.; Schaefer, L.A.

    1999-07-01

    After developing the theory of relativity, Albert Einstein spent several years working with Leo Szilard on absorption refrigeration cycles. In 1930, they obtained a US patent for a unique single pressure absorption cycle. The single pressure eliminates the need for a solution pump. Their cycle has only recently been rediscovered. The cycle utilizes butane as its refrigerant, ammonia as a pressure equalizing fluid, and water as an absorbing fluid. This cycle is dramatically different in both concept and detail than the better-known ammonia-water-hydrogen cycle. In this study, thermodynamic and mixture property models of the Einstein cycle were created to gain insight into the cycle's operating characteristics and to calculate its performance. A conceptual demonstration model was built and successfully operated, showing for the first time the viability of the cycle. The model results found that the system pressure is an important design parameter, with the COP having an optimum when the system pressure is equal to the saturation pressure of the butane refrigerant. It was also found that for a given system pressure, there is a maximum condenser-absorber temperature and a minimum evaporator temperature.

  3. Anhedonia: A Concept Analysis

    PubMed Central

    Ho, Nancy; Sommers, Marilyn

    2013-01-01

    Anhedonia presents itself in a myriad of disease processes. To further develop our understanding of anhedonia and effective ways to manage it, the concept requires clear boundaries. This paper critically examined the current scientific literature and conducted a concept analysis of anhedonia to provide a more accurate and lucid understanding the concept. As part of the concept analysis, this paper also provides model, borderline, related, and contrary examples of anhedonia. PMID:23706888

  4. Advanced propulsion concepts

    NASA Technical Reports Server (NTRS)

    Frisbee, Robert H.

    1991-01-01

    A variety of Advanced Propulsion Concepts (APC) is discussed. The focus is on those concepts that are sufficiently near-term that they could be developed for the Space Exploration Initiative. High-power (multi-megawatt) electric propulsion, solar sails, tethers, and extraterrestrial resource utilization concepts are discussed. A summary of these concepts and some general conclusions on their technology development needs are presented.

  5. Supersonic variable-cycle engines

    NASA Technical Reports Server (NTRS)

    Willis, E. A.; Welliver, A. D.

    1976-01-01

    The evolution and current status of selected recent variable cycle engine (VCE) studies are reviewed, and how the results were influenced by airplane requirements is described. Promising VCE concepts are described, their designs are simplified and the potential benefits in terms of aircraft performance are identified. This includes range, noise, emissions, and the time and effort it may require to ensure technical readiness of sufficient depth to satisfy reasonable economic, performance, and environmental constraints. A brief overview of closely related, ongoing technology programs in acoustics and exhaust emissions is also presented. Realistic technology advancements in critical areas combined with well matched aircraft and selected VCE concepts can lead to significantly improved economic and environmental performance relative to first generation SST predictions.

  6. Teach Life Science Concepts--with Picture Books.

    ERIC Educational Resources Information Center

    Texas Child Care, 2001

    2001-01-01

    Asserts that young children need help translating scientific theory into experiences that involve their senses. Provides age-appropriate, literature-based activities for exploring concepts and vocabulary in the areas of plant life cycles, animal life cycles, ocean ecology, and human growth development. Suggests specific works of children's…

  7. Sorption Refrigeration / Heat Pump Cycles

    NASA Astrophysics Data System (ADS)

    Saha, Bidyut Baran; Alam, K. C. Amanul; Hamamoto, Yoshinori; Akisawa, Atsushi; Kashiwagi, Takao

    Over the past few decades there have been considerable efforts to use adsorption (solid/vapor) for cooling and heat pump applications, but intensified efforts were initiated only since the imposition of international restrictions on the production and use of CFCs (chlorofluorocarbons) and HCFCs (hydrochlorofluorocarbons). Up to now, only the desiccant evaporative cooling system of the open type has achieved commercial use, predominantly in the United States. Closed-type adsorption refrigeration and heat pump systems are rarely seen in the market, or are still in the laboratory testing stage. Promising recent development have been made in Japan for the use of porous metal hydrides and composite adsorbents. In this paper, a short description of adsorption theories along with an overview of present status and future development trends of thermally powered adsorption refrigeration cycles are outlined putting emphasis on experimental achievements. This paper also addressed some advanced absorption cycles having relatively higher COP, and also summarizes fundamental concepts of GAX cycles and various GAX cycles developed for heat pump applications.

  8. A Preface to the Carnot Cycle.

    ERIC Educational Resources Information Center

    Goldstein, Martin

    1980-01-01

    Describes a new method for teaching the Second Law by way of the Carnot cycle. The two features of this method are that the isothermal process is considered first to establish some basic concepts, and then the nonisothermal cyclical process is introduced. (CS)

  9. Methanol decomposition bottoming cycle for IC engines

    NASA Technical Reports Server (NTRS)

    Purohit, G.; Houseman, J.

    1979-01-01

    This paper presents the concept of methanol decomposition using engine exhaust heat, and examines its potential for use in the operation of passenger cars, diesel trucks, and diesel-electric locomotives. Energy economy improvements of 10-20% are calculated over the representative driving cycles without a net loss in power. Some reductions in exhaust emissions are also projected.

  10. Variable-cycle engines for supersonic cruise aircraft

    NASA Technical Reports Server (NTRS)

    Willis, E.

    1976-01-01

    Progress and the current status of the Variable Cycle Engine (VCE) study are reviewed with emphasis placed on the impact of technology advancements and design specifications. A large variety of VCE concepts are also examined.

  11. E-Concept Mapping

    ERIC Educational Resources Information Center

    Shmaefsky, Brian R.

    2007-01-01

    Not all demonstrations involve using exciting visual displays of one or a series of scientific principles. Demonstrations can be as simple as showing the interrelationship between scientific concepts or principles using concept maps. Concepts maps are tools that help people conceptualize and remember a conglomeration of facts making up complex…

  12. Threshold Concepts in Biochemistry

    ERIC Educational Resources Information Center

    Loertscher, Jennifer

    2011-01-01

    Threshold concepts can be identified for any discipline and provide a framework for linking student learning to curricular design. Threshold concepts represent a transformed understanding of a discipline, without which the learner cannot progress and are therefore pivotal in learning in a discipline. Although threshold concepts have been…

  13. Applications of Concept Mapping

    ERIC Educational Resources Information Center

    De Simone, Christina

    2007-01-01

    This article reviews three major uses of the concept-mapping strategies for postsecondary learning: the external representation of concept maps as an external scratch pad to represent major ideas and their organization, the mental construction of concept maps when students are seeking a time-efficient tool, and the electronic construction and…

  14. Concepts: a potboiler.

    PubMed

    Fodor, J

    1994-01-01

    An informal, but revisionist, discussion of the role that the concept of a concept plays in recent theories of the cognitive mind. It is argued that the practically universal assumption that concepts are (at least partially) individuated by their roles in inferences is probably mistaken. A revival of conceptual atomism appears to be the indicated alternative. PMID:8039378

  15. Bracken Basic Concept Scale.

    ERIC Educational Resources Information Center

    Naglieri, Jack A.; Bardos, Achilles N.

    1990-01-01

    The Bracken Basic Concept Scale, for use with preschool and primary-aged children, determines a child's school readiness and knowledge of English-language verbal concepts. The instrument measures 258 basic concepts in such categories as comparisons, time, quantity, and letter identification. This paper describes test administration, scoring and…

  16. Behavioral Concepts in the Analysis of Chronic Pain Syndromes.

    ERIC Educational Resources Information Center

    Keefe, Francis J.; Gil, Karen M.

    1986-01-01

    Reviews behavioral and psychological concepts currently applied to the assessment and treatment of chronic pain syndromes, including operant conditioning and psychophysiologic concepts such as the stress-pain hypothesis, the pain-muscle spasm-pain cycle, and the neuromuscular pain model. Discusses relaxation and biofeedback training and concepts…

  17. The FOT tool kit concept

    NASA Technical Reports Server (NTRS)

    Fatig, Michael

    1993-01-01

    Flight operations and the preparation for it has become increasingly complex as mission complexities increase. Further, the mission model dictates that a significant increase in flight operations activities is upon us. Finally, there is a need for process improvement and economy in the operations arena. It is therefore time that we recognize flight operations as a complex process requiring a defined, structured, and life cycle approach vitally linked to space segment, ground segment, and science operations processes. With this recognition, an FOT Tool Kit consisting of six major components designed to provide tools to guide flight operations activities throughout the mission life cycle was developed. The major components of the FOT Tool Kit and the concepts behind the flight operations life cycle process as developed at NASA's GSFC for GSFC-based missions are addressed. The Tool Kit is therefore intended to increase productivity, quality, cost, and schedule performance of the flight operations tasks through the use of documented, structured methodologies; knowledge of past lessons learned and upcoming new technology; and through reuse and sharing of key products and special application programs made possible through the development of standardized key products and special program directories.

  18. Modelisation numerique et validation experimentale d'un systeme de protection contre le givre par elements piezoelectriques

    NASA Astrophysics Data System (ADS)

    Harvey, Derek

    Le degivrage au moyen d'actuateurs piezoelectriques est considere comme une avenue prometteuse pour le developpement de systemes a faible consommation d'energie applicables aux helicopteres legers. Ce type de systeme excite des frequences de resonances d'une structure pour produire des deformations suffisantes pour rompre l'adherence de la glace. Par contre, la conception de tel systeme demeure generalement mal comprise. Ce projet de maitrise etudie l'utilisation de methodes numeriques pour assister la conception des systemes de protection contre le givre a base d'elements piezoelectriques. La methodologie retenue pour ce projet a ete de modeliser differentes structures simples et de simuler l'excitation harmonique des frequences de resonance au moyen d'actuateurs piezoelectriques. Le calcul des frequences de resonances ainsi que la simulation de leur excitation a ensuite ete validee a l'aide de montages experimentaux. La procedure a ete realisee pour une poutre en porte-a-faux et pour une plaque plane a l'aide du logiciel de calcul par elements finis, Abaqus. De plus, le modele de la plaque plane a ete utilise afin de realiser une etude parametrique portant sur le positionnement des actuateurs, l'effet de la rigidite ainsi que de l'epaisseur de la plaque. Finalement, la plaque plane a ete degivree en chambre climatique. Des cas de degivrage ont ete simules numeriquement afin d'etudier la possibilite d'utiliser un critere base sur la deformation pour predire le succes du systeme. La validation experimentale a confirme la capacite du logiciel a calculer precisement a la fois les frequences et les modes de resonance d'une structure et a simuler leur excitation par des actuateurs piezoelectriques. L'etude revele que la definition de l'amortissement dans le modele numerique est essentiel pour l'obtention de resultats precis. Les resultats de l'etude parametrique ont demontre l'importance de minimiser l'epaisseur et la rigidite afin de reduire la valeur des frequences

  19. Le déficit immunitaire humoral: mieux le connaître pour mieux le prendre en charge

    PubMed Central

    El Bakkouri, Jalila; Aadam, Zahra; Ailal, Fatima; Alj, Hanane Salih; Bousfiha, Ahmed Aziz

    2014-01-01

    Les déficits immunitaires humoraux (DIH) sont des maladies hétérogènes allant des formes asymptomatiques rencontrés lors des déficits sélectifs en immunoglobulines A (IgA) et en sous-classes d'IgG aux formes graves des agammaglobulinémies congénitales. Les patients atteints de DIH présentent souvent des infections ORL ou des voies respiratoires récidivantes ou sévères. Ces patients peuvent présenter un certain nombre de complications non infectieuses, telles que des manifestations auto-immunes et des entéropathies, qui pourraient être le seul symptôme clinique révélateur. Les formes sévères des DIH sont facilement diagnostiquées grâce au dosage des IgG totaux, des IgA et des IgM. La thérapie substitutive par les immunoglobulines reste le traitement de choix chez ces patients. PMID:25489366

  20. Concept analysis of mentoring.

    PubMed

    2013-10-01

    The purpose of a concept analysis is to examine the structure and function of a concept by defining its attributes and internal structure. Concept analysis can clarify an overused or vague concept and promote mutual understanding by providing a precise operational definition. Mentoring is a concept more fully used by other fields, such as business, than in nursing and may not always translate well for use in nursing. Therefore, clarifying the meaning of the existing concept of mentoring and developing an operational definition for use in nursing are aims of this concept analysis. Mentoring is broadly based and concentrates on developing areas such as career progression, scholarly achievements, and personal development. Mentoring relationships are based around developing reciprocity and accountability between each partner. Mentoring is seen related to transition in practice, role acquisition, and socialization, as a way to support new colleagues. Mentorship is related to nurses' success in nursing practice linked to professionalism, nursing quality improvement, and self-confidence. PMID:24042140

  1. Solar Cycle 25: Another Moderate Cycle?

    NASA Astrophysics Data System (ADS)

    Cameron, R. H.; Jiang, J.; Schüssler, M.

    2016-06-01

    Surface flux transport simulations for the descending phase of Cycle 24 using random sources (emerging bipolar magnetic regions) with empirically determined scatter of their properties provide a prediction of the axial dipole moment during the upcoming activity minimum together with a realistic uncertainty range. The expectation value for the dipole moment around 2020 (2.5 ± 1.1 G) is comparable to that observed at the end of Cycle 23 (about 2 G). The empirical correlation between the dipole moment during solar minimum and the strength of the subsequent cycle thus suggests that Cycle 25 will be of moderate amplitude, not much higher than that of the current cycle. However, the intrinsic uncertainty of such predictions resulting from the random scatter of the source properties is considerable and fundamentally limits the reliability with which such predictions can be made before activity minimum is reached.

  2. Understanding of Earth and Space Science Concepts: Strategies for Concept-Building in Elementary Teacher Preparation

    ERIC Educational Resources Information Center

    Bulunuz, Nermin; Jarrett, Olga S.

    2009-01-01

    This research is concerned with preservice teacher understanding of six earth and space science concepts that are often taught in elementary school: the reason for seasons, phases of the moon, why the wind blows, the rock cycle, soil formation, and earthquakes. Specifically, this study examines the effect of readings, hands-on learning stations,…

  3. Continuing education in nursing: a concept analysis.

    PubMed

    Gallagher, Lorraine

    2007-07-01

    The importance of continuing education for nurses has been increasingly emphasized in the nursing literature since the beginning of the profession. The concept of continuing education is often used as a substitute for associated terms such as continuing professional development and lifelong learning, thus highlighting a need for its clarification. The purpose of this article is to explain and describe continuing education, in order to encourage a broader understanding of the concept among nurses. The concept analysis is directed by Rodgers' [Rodgers, B.L., 1989. Concept analysis and the development of nursing knowledge: the evolutionary cycle. Journal of Advanced Nursing 14, 330-335] 'evolutionary approach' which is viewed as an ongoing dynamic process, and one that identifies the shared meaning of concepts. Examining everyday discourse used in the nursing literature identified the critical attributes, antecedents and consequence of continuing education in nursing. As a result, the emerging attributes of the concept are synthesised into a conceptual model. The article concludes with an exploration of the application of the concept of continuing education within nursing and its implications for professional development. PMID:17109998

  4. THE EPA'S EMERGING FOCUS ON LIFE CYCLE ASSESSMENT

    EPA Science Inventory

    EPA has been actively engaged in LCA research since 1990 to help advance the methodology and application of life cycle thinking in decision making. Across the Agency consideration of the life cycle concept is increasing in the development of policies and programs. A major force i...

  5. Lele de l’omalizumab dans le traitement de l’asthme allergique grave

    PubMed Central

    Chapman, Kenneth R; Cartier, André; Hébert, Jacques; McIvor, R Andrew; Schellenberg, R Robert

    2006-01-01

    CONTEXTE : Un nouveau traitement anti-immunoglobuline E (anti-IgE) contre l’asthme, l’omalizumab, a été approuvé au Canada. OBJECTIF : Passer en revue les données fondamentales et cliniques sur l’omalizumab et examiner lele possible de ce médicament dans la prise en charge de l’asthme au Canada. MÉTHODOLOGIE : Une recherche documentaire a été effectuée dans MEDLINE afin de repérer les études menées de 1960 à 2006 sur l’omalizumab. La recherche a également porté sur les résumés de réunions scientifiques récentes dans le domaine des maladies respiratoires et des allergies; par ailleurs, toute donnée non publiée a été demandée au fabricant. Après avoir revu et résumé les données, un comité mixte constitué de spécialistes des maladies respiratoires et des allergies a rédigé un ensemble de recommandations relatives à l’utilisation de l’omalizumab. RÉSULTATS : L’omalizumab est un anticorps monoclonal humanisé qui se lie au domaine C epsilon 3 de la molécule d’IgE pour former des complexes immuns solubles qui sont éliminés par le système réticulo-endothélial. L’administration d’injections sous-cutanées espacées de deux ou de quatre semaines à la dose recommandée entraîne une diminution rapide des taux d’IgE circulantes libres. Lors de deux essais cliniques de phase III menés auprès de 1 405 adultes et adolescents atteints d’asthme modéré à grave qui recevaient des doses moyennes stables de corticostéroïdes en inhalation (CSI), l’omalizumab a diminué les taux d’exacerbation par rapport au placebo et a été associé à une amélioration des symptômes ainsi qu’à une épargne plus importante des corticostéroïdes. Dans un essai mené auprès de 419 patients atteints d’asthme grave non maîtrisé malgré l’utilisation de doses élevées de CSI et de la prise concomitante d’agonistes bêta-2 à action prolongée, les exacerbations graves étaient de 50 % moins fréquentes chez

  6. Fast Track'' nuclear thermal propulsion concept

    SciTech Connect

    Johnson, R.A.; Zweig, H.R. ); Cooper, M.H.; Wett, J. Jr. )

    1993-01-10

    The objective of the Space Exploration Initiative ( America at the Threshold...,'' 1991) is the exploration of Mars by man in the second decade of the 21st century. The NASA Fast Track'' approach (NASA-LeRC Presentation, 1992) could accelerate the manned exploration of Mars to 2007. NERVA-derived nuclear propulsion represents a viable near-term technology approach to accomplish the accelerated schedule. Key milestones in the progression to the manned Mars mission are (1) demonstration of TRL-6 for the man-rateable system by 1999, (2) a robotic lunar mission by 2000, (3) the first cargo mission to Mars by 2005, and (4) the piloted Mars mission in 2007. The Rocketdyne-Westinghouse concept for nuclear thermal propulsion to achieve these milestones combines the nuclear reactor technology of the Rover/NERVA programs and the state-of-the-art hardware designs from hydrogen-fueled rocket engine successes like the Space Shuttle Main Engine (SSME).

  7. Reproductive cycles of buffalo.

    PubMed

    Perera, B M A O

    2011-04-01

    The domestic water buffalo (Bubalus bubalis) has an important role in the agricultural economy of many developing countries in Asia, providing milk, meat and draught power. It is also used in some Mediterranean and Latin American countries as a source of milk and meat for specialized markets. Although the buffalo can adapt to harsh environments and live on poor quality forage, reproductive efficiency is often compromised by such conditions, resulting in late sexual maturity, long postpartum anoestrus, poor expression of oestrus, poor conception rates and long calving intervals. The age at puberty is influenced by genotype, nutrition, management and climate, and under favourable conditions occurs at 15-18 months in river buffalo and 21-24 months in swamp buffalo. The ovaries are smaller than in cattle and contain fewer primordial follicles. Buffalo are capable of breeding throughout the year, but in many countries a seasonal pattern of ovarian activity occurs. This is attributed in tropical regions to changes in rainfall resulting in feed availability or to temperature stress resulting in elevated prolactin secretion, and in temperate regions to changes in photoperiod and melatonin secretion. The mean length of the oestrous cycle is 21 days, with greater variation than observed in cattle. The signs of oestrus in buffalo are less overt than in cattle and homosexual behaviour between females is rare. The duration of oestrus is 5-27 h, with ovulation occurring 24-48 h (mean 34 h) after the onset of oestrus. The hormonal changes occurring in peripheral circulation are similar to those observed in cattle, but the peak concentrations of progesterone and oestradiol-17β are less. The number of follicular waves during an oestrous cycle varies from one to three and influences the length of the luteal phase as well as the inter-ovulatory interval. Under optimal conditions, dairy types managed with limited or no suckling resume oestrus cyclicity by 30-60 days after calving

  8. Reconciliation--A Rhetorical Concept/ion

    ERIC Educational Resources Information Center

    Doxtader, Erik

    2003-01-01

    What is reconciliation? A source of historical puzzlement and contemporary controversy over how to make history, this question asks after those words which constitute a beginning (again), that moment in which endless cycles of conflict give way to the hope for "unity in difference." Concerned with the dynamics of its operation, the present essay…

  9. Time to Pregnancy: A Computational Method for Using the Duration of Non-Conception for Predicting Conception

    PubMed Central

    Sozou, Peter D.; Hartshorne, Geraldine M.

    2012-01-01

    An important problem in reproductive medicine is deciding when people who have failed to become pregnant without medical assistance should begin investigation and treatment. This study describes a computational approach to determining what can be deduced about a couple's future chances of pregnancy from the number of menstrual cycles over which they have been trying to conceive. The starting point is that a couple's fertility is inherently uncertain. This uncertainty is modelled as a probability distribution for the chance of conceiving in each menstrual cycle. We have developed a general numerical computational method, which uses Bayes' theorem to generate a posterior distribution for a couple's chance of conceiving in each cycle, conditional on the number of previous cycles of attempted conception. When various metrics of a couple's expected chances of pregnancy were computed as a function of the number of cycles over which they had been trying to conceive, we found good fits to observed data on time to pregnancy for different populations. The commonly-used standard of 12 cycles of non-conception as an indicator of subfertility was found to be reasonably robust, though a larger or smaller number of cycles may be more appropriate depending on the population from which a couple is drawn and the precise subfertility metric which is most relevant, for example the probability of conception in the next cycle or the next 12 cycles. We have also applied our computational method to model the impact of female reproductive ageing. Results indicate that, for women over the age of 35, it may be appropriate to start investigation and treatment more quickly than for younger women. Ignoring reproductive decline during the period of attempted conception added up to two cycles to the computed number of cycles before reaching a metric of subfertility. PMID:23056338

  10. Une nouvelle approche du contenu thematique et situationnel d'une methode audio-visuelle: 'C'est le Printemps' (A New Approach to Thematic and Situational Content in an Audio-Visual Method: 'C'est le Printemps'). Acts of the Colloquium of the Swiss Interuniversity Commission for Applied Linguistics. CILA Bulletin, No. 26.

    ERIC Educational Resources Information Center

    Gschwind-Holtzer, G.

    This study attempts to demonstrate that the choice of material on the thematic and situational level has a bearing on linguistic concepts. The critique is divided into three main sections dealing with: (1) themes and situations, or the world view of audio-visual methods; (2) themes and situations in a particular text, "C'est le printemps;" and (3)…

  11. Evolving Ethical Concepts

    ERIC Educational Resources Information Center

    Potter, Van Rensselaer

    1977-01-01

    Discusses the role of the scientist in changing ethical concepts from simple interpersonal and theological imperatives towards "survival imperatives that must form the core of environmental bioethics." (CS)

  12. Statistical cyclicity of the supercontinent cycle

    NASA Astrophysics Data System (ADS)

    Rolf, T.; Coltice, N.; Tackley, P. J.

    2014-04-01

    Supercontinents like Pangea impose a first-order control on Earth's evolution as they modulate global heat loss, sea level, climate, and biodiversity. In a traditional view, supercontinents form and break up in a regular, perhaps periodic, manner in a cycle lasting several 100 Myr as reflected in the assembly times of Earth's major continental aggregations: Columbia, Rodinia, and Pangea. However, modern views of the supercontinent cycle propose a more irregular evolution on the basis of an improved understanding of the Precambrian geologic record. Here we use fully dynamic spherical mantle convection models featuring plate-like behavior and continental drift to investigate supercontinent formation and breakup. We further dismiss the concept of regularity but suggest a statistical cyclicity in which the supercontinent cycle may have a characteristic period imposed by mantle and lithosphere properties, but this is hidden in immense fluctuations between different cycles that arise from the chaotic nature of mantle flow.

  13. Mapping commuter cycling risk in urban areas.

    PubMed

    Yiannakoulias, Nikolaos; Bennet, Scott A; Scott, Darren M

    2012-03-01

    Cycling is becoming an increasingly important transportation option for commuters. Cycling offers exercise opportunities and reduces the burden of motor vehicle travel on society. Mapping the risk of collision between cyclists and motor vehicles in urban areas is important to understanding safe cyclist route opportunities, making informed transportation planning decisions, and exploring patterns of injury epidemiology. To date, many geographic analyses and representations of cyclist risk have not taken the concept of exposure into account. Instead, risk is either expressed as a rate per capita, or as a count of events. Using data associated with the City of Hamilton, Canada, we illustrate a method for mapping commuter cyclist collision risk per distance travelled. This measure can be used to more realistically represent the underlying geography of cycling risk, and provide more geographically and empirically meaningful information to those interested in understanding how cycling safety varies over space. PMID:22269497

  14. A model for the construction of elementary concepts

    NASA Astrophysics Data System (ADS)

    von Glasersfeld, Ernst

    1999-03-01

    In his paper Les épistémologies constructivistes: Un nouveau commencement (Sciences de la Société, n°40, 1997), Jean-Louis Le Moigne poses the question: "Le rêve d'une connaissance autoréférentielle se fondant sur elle-même, est sans doute fascinant … Mais est-il scientifiquement raisonnable?". Building on the work of Jean Piaget, I shall try to show through a developmental analysis of elementary, scientifically relevant concepts, such as `change', `object permanence', `space', and `time', that the notion of the thinking subject's construction of knowledge constitutes a more reasonable foundation for science than the traditional belief in the representation of objective reality.

  15. Intracranial subdural hygroma after Le Fort I osteotomy.

    PubMed

    Thompson, William L; Lee, Michael; MacIntosh, Robert Bruce

    2015-04-01

    Various intra- and postoperative complications have been well-documented after Le Fort I osteotomies; however, an intracranial subdural hygroma has not yet been reported in oral and maxillofacial studies. We report a unique case of an intracranial subdural hygroma requiring neurosurgical intervention after Le Fort I advancement. PMID:25631863

  16. Cycling To Awareness.

    ERIC Educational Resources Information Center

    Kozak, Stan

    1999-01-01

    Encourages environmental and outdoor educators to promote bicycling. In the community and the curriculum, cycling connects environmental issues, health and fitness, law and citizenship, appropriate technology, and the joy of being outdoors. Describes the Ontario Cycling Association's cycling strategy and its four components: school cycling…

  17. HIV Life Cycle

    MedlinePlus

    HIV Overview The HIV Life Cycle (Last updated 9/8/2016; last reviewed 9/8/2016) Key Points HIV gradually destroys the immune ... life cycle. What is the connection between the HIV life cycle and HIV medicines? Antiretroviral therapy (ART) ...

  18. Industrial ecology: concepts and approaches.

    PubMed Central

    Jelinski, L W; Graedel, T E; Laudise, R A; McCall, D W; Patel, C K

    1992-01-01

    Industrial ecology is a new approach to the industrial design of products and processes and the implementation of sustainable manufacturing strategies. It is a concept in which an industrial system is viewed not in isolation from its surrounding systems but in concert with them. Industrial ecology seeks to optimize the total materials cycle from virgin material to finished material, to component, to product, to waste product, and to ultimate disposal. To better characterize the topic, the National Academy of Sciences convened a colloquium from which were derived a number of salient contributions. This paper sets the stage for the contributions that follow and discusses how each fits into the framework of industrial ecology. PMID:11607253

  19. Advanced Fuel Cycle Cost Basis

    SciTech Connect

    D. E. Shropshire; K. A. Williams; W. B. Boore; J. D. Smith; B. W. Dixon; M. Dunzik-Gougar; R. D. Adams; D. Gombert; E. Schneider

    2008-03-01

    This report, commissioned by the U.S. Department of Energy (DOE), provides a comprehensive set of cost data supporting a cost analysis for the relative economic comparison of options for use in the Advanced Fuel Cycle Initiative (AFCI) Program. The report describes the AFCI cost basis development process, reference information on AFCI cost modules, a procedure for estimating fuel cycle costs, economic evaluation guidelines, and a discussion on the integration of cost data into economic computer models. This report contains reference cost data for 25 cost modules—23 fuel cycle cost modules and 2 reactor modules. The cost modules were developed in the areas of natural uranium mining and milling, conversion, enrichment, depleted uranium disposition, fuel fabrication, interim spent fuel storage, reprocessing, waste conditioning, spent nuclear fuel (SNF) packaging, long-term monitored retrievable storage, near surface disposal of low-level waste (LLW), geologic repository and other disposal concepts, and transportation processes for nuclear fuel, LLW, SNF, transuranic, and high-level waste.

  20. Advanced Fuel Cycle Cost Basis

    SciTech Connect

    D. E. Shropshire; K. A. Williams; W. B. Boore; J. D. Smith; B. W. Dixon; M. Dunzik-Gougar; R. D. Adams; D. Gombert

    2007-04-01

    This report, commissioned by the U.S. Department of Energy (DOE), provides a comprehensive set of cost data supporting a cost analysis for the relative economic comparison of options for use in the Advanced Fuel Cycle Initiative (AFCI) Program. The report describes the AFCI cost basis development process, reference information on AFCI cost modules, a procedure for estimating fuel cycle costs, economic evaluation guidelines, and a discussion on the integration of cost data into economic computer models. This report contains reference cost data for 26 cost modules—24 fuel cycle cost modules and 2 reactor modules. The cost modules were developed in the areas of natural uranium mining and milling, conversion, enrichment, depleted uranium disposition, fuel fabrication, interim spent fuel storage, reprocessing, waste conditioning, spent nuclear fuel (SNF) packaging, long-term monitored retrievable storage, near surface disposal of low-level waste (LLW), geologic repository and other disposal concepts, and transportation processes for nuclear fuel, LLW, SNF, and high-level waste.

  1. Advanced Fuel Cycle Cost Basis

    SciTech Connect

    D. E. Shropshire; K. A. Williams; W. B. Boore; J. D. Smith; B. W. Dixon; M. Dunzik-Gougar; R. D. Adams; D. Gombert; E. Schneider

    2009-12-01

    This report, commissioned by the U.S. Department of Energy (DOE), provides a comprehensive set of cost data supporting a cost analysis for the relative economic comparison of options for use in the Advanced Fuel Cycle Initiative (AFCI) Program. The report describes the AFCI cost basis development process, reference information on AFCI cost modules, a procedure for estimating fuel cycle costs, economic evaluation guidelines, and a discussion on the integration of cost data into economic computer models. This report contains reference cost data for 25 cost modules—23 fuel cycle cost modules and 2 reactor modules. The cost modules were developed in the areas of natural uranium mining and milling, conversion, enrichment, depleted uranium disposition, fuel fabrication, interim spent fuel storage, reprocessing, waste conditioning, spent nuclear fuel (SNF) packaging, long-term monitored retrievable storage, near surface disposal of low-level waste (LLW), geologic repository and other disposal concepts, and transportation processes for nuclear fuel, LLW, SNF, transuranic, and high-level waste.

  2. Analyse de L'ancrage des Vortex Intergrains pour le Yttrium BARYUM(2) CUIVRE(3) OXYGENE(7) Polycristallin

    NASA Astrophysics Data System (ADS)

    Fournier, Patrick

    Le Modele de l'Etat Critique Generalise (MECG) est utilise pour decrire les proprietes magnetiques et de transport du YBa_2Cu_3O _7 polycristallin. Ce modele empirique permet de relier la densite de courant critique a la densite de lignes de flux penetrant dans la region intergrain. Deux techniques de mesures sont utilisees pour caracteriser nos materiaux. La premiere consiste a mesurer le champ au centre d'un cylindre creux en fonction du champ magnetique applique pour des temperatures comprises entre 20 et 85K. En variant l'epaisseur de la paroi du cylindre creux, il est possible de suivre l'evolution des cycles d'hysteresis et de determiner des champs caracteristiques qui varient en fonction de cette dimension. En utilisant un lissage des resultats experimentaux, nous determinons J _{co}, H_ {o} et n, les parametres du MECG. La forme des cylindres, avec une longueur comparable au diametre externe, entrai ne la presence d'un champ demagnetisant qui peut etre inclus dans le modele theorique. Ceci nous permet d'evaluer la fraction du volume ecrante, f _{g}, ainsi que le facteur demagnetisant N. Nous trouvons que J_{ co}, H_{o} et f_{g} dependent de la temperature, tandis que n et N (pour une epaisseur de paroi fixe) n'en dependent pas. La deuxieme technique consiste a mesurer le courant critique de lames minces en fonction du champ applique pour differentes temperatures. Nous utilisons un montage que nous avons developpe permettant d'effectuer ces mesures en contact direct avec le liquide refrigerant, i.e. dans l'azote liquide. Nous varions la temperature du liquide en variant la pression du gaz au-dessus du bain d'azote. Cette methode nous permet de balayer des temperatures entre 65K et la temperature critique du materiau ({~ }92K). Nous effectuons le lissage des courbes de courant critique en fonction du champ applique encore a l'aide du MECG, pour a nouveau obtenir ses parametres. Pour trois echantillons avec des traitements thermiques differents, les parametres

  3. The Use of Le by L1 Chinese Speakers and the Acquisition of Le by L2 Chinese Learners

    ERIC Educational Resources Information Center

    Bredeche, Chi Chen

    2011-01-01

    The perfective marker V-"le" is claimed to be one of the most problematic items in the acquisition of L2 Chinese, perhaps because no unified and comprehensive treatment of it exists in the literature. Although much has been written on this topic, the semantic and pragmatic functions of V-"le" have remained elusive. While linguists and grammarians…

  4. Energy levels, wavelengths, and radiative transition probabilities for the Na-like ions with 38 [le] Z [le] 45

    SciTech Connect

    Ying Zhang; Qiren Zhu; Shoufu Pan )

    1992-11-01

    The investigation by Z.-Q Zhang et al. (Acta Optica Sinica 11, 193, 1991) shows that it is possible to realize soft X-ray lasing in the water window 23.3-43.8 [Angstrom] with the Na-like recombination scheme, which requires a lower pumping power at a high-power laser facility than that with other schemes. The fine-structure levels with n [le] 15 and l [le] 6 in Na-like ions with 38 [le] Z [le] 45 and the probabilities for radiative transitions between these levels are calculated using the multiconfiguration Dirac-Fock approach. The calculations show that the wavelengths of the anticipated laser transitions 6 f-4d and 6g-4f in the Na-like ions with 38 [le] Z [le] 43 and 5f-4d and 5g-4f in the Na-like ions with 40 [le] Z [le] 45 lie in the region of the water window.

  5. Advanced Airspace Concept

    NASA Technical Reports Server (NTRS)

    Erzberger, Heinz

    2002-01-01

    A general overview of the Advanced Airspace Concept (AAC) is presented. The topics include: 1) Limitations of the existing system; 2) The Advanced Airspace Concept; 3) Candidate architecture for the AAC; 4) Separation assurance and conflict avoidance system (TSAFE); and 5) Ground-Air Interactions. This paper is in viewgraph form.

  6. Learning Our Concepts

    ERIC Educational Resources Information Center

    Laverty, Megan J.

    2009-01-01

    Richard Stanley Peters appreciates the centrality of concepts for everyday life, however, he fails to recognize their pedagogical dimension. He distinguishes concepts employed at the first-order (our ordinary language-use) from second-order conceptual clarification (conducted exclusively by academically trained philosophers). This distinction…

  7. Children's Conceptions of Jesus

    ERIC Educational Resources Information Center

    Aylward, Karen; Freathy, Rob

    2008-01-01

    This paper presents findings from a recent study investigating young children's (aged 10-11) conceptions of Jesus in England. The overall picture revealed by the study is that whilst there was a general assent amongst pupils in our sample towards an ethical and humanistic conception of the historical Jesus, there was less of a consensus about…

  8. Badminton--Teaching Concepts.

    ERIC Educational Resources Information Center

    Gibbs, Marilyn J.

    1988-01-01

    Teaching four basic badminton concepts along with the usual basic skill shots allows players to develop game strategy awareness as well as mechanical skills. These four basic concepts are: (1) ready position, (2) flight trajectory, (3) early shuttle contact, and (4) camouflage. (IAH)

  9. Data Transmission Concepts.

    ERIC Educational Resources Information Center

    Christenson, Chris

    1995-01-01

    Introduces some basic concepts related to the transmission of data from a computer to its peripherals to help distance educators make decisions regarding computer equipment purchases for their institutions. The following data transmission concepts are described: cables, serial and parallel, synchronous and asynchronous, bandwidth, and analog and…

  10. VOCABULARY AND CONCEPT DEVELOPMENT.

    ERIC Educational Resources Information Center

    LANGER, JOHN H.

    THE PROCESSES OF THOUGHT, OF CONCEPT DEVELOPMENT, AND OF VOCABULARY DEVELOPMENT ARE SIGNIFICANTLY INTERRELATED. COMMUNICATION OF IDEAS DEPENDS UPON THE ABILITY TO ASSOCIATE WRITTEN AND VERBAL SYMBOLS WITH THE REFERENTS THROUGH A SYSTEMATIC PROCESS OF REORGANIZING AND INTEGRATING OLD AND NEW CONCEPTS. THE ABILITY TO ASSOCIATE, IN TURN, DEPENDS UPON…

  11. The Concept of Validity

    ERIC Educational Resources Information Center

    Borsboom, Denny; Mellenbergh, Gideon J.; van Heerden, Jaap

    2004-01-01

    This article advances a simple conception of test validity: A test is valid for measuring an attribute if (a) the attribute exists and (b) variations in the attribute causally produce variation in the measurement outcomes. This conception is shown to diverge from current validity theory in several respects. In particular, the emphasis in the…

  12. Threshold Concepts in Economics

    ERIC Educational Resources Information Center

    Shanahan, Martin

    2016-01-01

    Purpose: The purpose of this paper is to examine threshold concepts in the context of teaching and learning first-year university economics. It outlines some of the arguments for using threshold concepts and provides examples using opportunity cost as an exemplar in economics. Design/ Methodology/Approach: The paper provides an overview of the…

  13. Values Concepts and Techniques.

    ERIC Educational Resources Information Center

    National Education Association, Washington, DC.

    This book contains 29 articles for elementary and secondary teachers dealing with fundamental concepts and teaching techniques in values education. Part one of the book deals with concepts. Louis E. Raths examines valuing and its relationship to freedom and intelligence. The cognitive developmental approach to moral education is discussed by…

  14. Transition: Terms and Concepts.

    ERIC Educational Resources Information Center

    O'Leary, Ed

    This paper provides explanations and case examples of some terms and concepts related to transition of students with disabilities under 1997 amendments to the Individuals with Disabilities Education Act. Explanations and examples focus on the concepts of "statement of transition service needs" and "statement of needed transition services". The…

  15. Tools and Concepts.

    ERIC Educational Resources Information Center

    Artis, Margaret, Ed.; And Others

    This guide provides enrichment for students to develop tools and concepts used in various areas of mathematics. The first part presents arithmetic progressions, geometric progressions, and harmonic progression. In the second section, the concept of mathematic induction is developed from intuitive induction, using concrete activities, to the…

  16. The Self Concept.

    ERIC Educational Resources Information Center

    Fitzgibbon, Ann

    The purpose of this paper is to increase awareness of the self concept as a variable, to indicate what is known about the self concept from existing research, to discuss its importance to the school and its effect on learning, and to offer a method of assessment which is tied to a definition arbitrarily made as a starting point for researchers. A…

  17. Changing Concepts in Forensics.

    ERIC Educational Resources Information Center

    Zarefsky, David

    This paper discusses five theoretical concepts in general and two theoretical models in particular that are involved in forensics. The five concepts are: (1) causation, an inquiry into the reasons for ongoing processes or problems; (2) inherency, the division of a universe into its necessary features and its accidental features; (3) presumption, a…

  18. A combined cycle engine test facility

    NASA Astrophysics Data System (ADS)

    Engers, R.; Cresci, D.; Tsai, C.

    Rocket-Based Combined-Cycle (RBCC) engines intended for missiles and/or space launch applications incorporate features of rocket propulsion systems operating in concert with airbreathing engine cycles. Performance evaluation of these types of engines, which are intended to operate from static sea level take-off to supersonic cruise or accerlerate to orbit, requires ground test capabilities which integrate rocket component testing with airbreathing engine testing. A combined cycle engine test facility has been constructed in the General Applied Science Laboratories, Inc. (GASL) Aeropropulsion Test Laboratory to meet this requirement. The facility was designed to support the development of an innovative combined cycle engine concept which features a rocket based ramjet combustor. The test requirements included the ability to conduct tests in which the propulsive force was generated by rocket only, the ramjet only and simultaneous rocket and ramjet power (combined cycle) to evaluate combustor operation over the entire engine cycle. The test facility provides simulation over the flight Mach number range of 0 to 8 and at various trajectories. The capabilities of the combined cycle engine test facility are presented.

  19. A combined cycle engine test facility

    SciTech Connect

    Engers, R.; Cresci, D.; Tsai, C.

    1995-09-01

    Rocket-Based Combined-Cycle (RBCC) engines intended for missiles and/or space launch applications incorporate features of rocket propulsion systems operating in concert with airbreathing engine cycles. Performance evaluation of these types of engines, which are intended to operate from static sea level take-off to supersonic cruise or accerlerate to orbit, requires ground test capabilities which integrate rocket component testing with airbreathing engine testing. A combined cycle engine test facility has been constructed in the General Applied Science Laboratories, Inc. (GASL) Aeropropulsion Test Laboratory to meet this requirement. The facility was designed to support the development of an innovative combined cycle engine concept which features a rocket based ramjet combustor. The test requirements included the ability to conduct tests in which the propulsive force was generated by rocket only, the ramjet only and simultaneous rocket and ramjet power (combined cycle) to evaluate combustor operation over the entire engine cycle. The test facility provides simulation over the flight Mach number range of 0 to 8 and at various trajectories. The capabilities of the combined cycle engine test facility are presented.

  20. Le contrôle des infections au cabinet du pédiatre

    PubMed Central

    2008-01-01

    RÉSUMÉ La transmission des infections au cabinet du pédiatre est de plus en plus préoccupante. Le présent document expose les voies de transmission des infections et les principes sous-jacents aux mesures actuelles pour contrôler les infections. Pour prévenir les infections, il faut bien concevoir le cabinet et adopter des politiques administratives et de triage convenables, de même que des pratiques de base pour les soins de tous les patients (p. ex., hygiène des mains, port de gants, de masques, de lunettes de protection et d’une blouse d’hôpital pour des interventions précises; nettoyage, désinfection et stérilisation convenables des surfaces et du matériel, y compris les jouets, et techniques d’asepsie en cas d’interventions effractives) et des précautions additionnelles en cas d’infections précises. Le personnel doit avoir reçu les vaccins pertinents, et les personnes infectées doivent respecter les politiques de restriction au travail.

  1. EDOS operations concept and development approach

    NASA Technical Reports Server (NTRS)

    Knoble, G.; Garman, C.; Alcott, G.; Ramchandani, C.; Silvers, J.

    1994-01-01

    The Earth Observing System (EOS) Data and Operations System (EDOS) is being developed by the National Aeronautics and Space Administration (NASA) Goddard Space Flight Center (GSFC) for the capture, level zero processing, distribution, and backup archiving of high speed telemetry data received from EOS spacecraft. All data received will conform to the Consultative Committee for Space Data Standards (CCSDS) recommendations. The major EDOS goals are to: (1) minimize EOS program costs to implement and operate EDOS; (2) respond effectively to EOS growth requirements; and (3) maintain compatibility with existing and enhanced versions of NASA institutional systems required to support EOS spacecraft. In order to meet these goals, the following objectives have been defined for EDOS: (1) standardize EDOS interfaces to maximize utility for future requirements; (2) emphasize life-cycle cost (LCC) considerations (rather than procurement costs) in making design decisions and meeting reliability, maintainability, availability (RMA) and upgradability requirements; (3) implement data-driven operations to the maximum extent possible to minimize staffing requirements and to maximize system responsiveness; (4) provide a system capable of simultaneously supporting multiple spacecraft, each in different phases of their life-cycles; (5) provide for technology insertion features to accommodate growth and future LCC reductions during the operations phase; and (6) provide a system that is sufficiently robust to accommodate incremental performance upgrades while supporting operations. Operations concept working group meetings were facilitated to help develop the EDOS operations concept. This provided a cohesive concept that met with approval of responsible personnel from the start. This approach not only speeded up the development process by reducing review cycles, it also provided a medium for generating good ideas that were immediately molded into feasible concepts. The operations concept

  2. Feminism: a concept analysis.

    PubMed

    Allan, H T

    1993-10-01

    The purpose of this paper is to analyse the concept of feminism in order to clarify a sociological concept for its use in nursing theory and practice. This analysis is carried out using the Walker & Avant (1988) model. It includes: a literature review, an overview of the uses of the concept drawn from the literature, the defining attributes and the justification of their choice, the cases to demonstrate the concept, and the concept criteria. The concept was chosen out of an interest in developing a feminist nursing theory and desire to enhance nursing practice. The literature search proved most fruitful in the sociological literature. The nursing sources were fewer and concerned with practice rather than articulating any feminist nursing theory. Many of these sources were sociologists and nurses. The concept of feminism was defined as the concern with gender equality and the promotion of equal rights for men and woman, the expression of these concerns through theory or action, and the valuing of individuals for their contributions to society rather than their biological or sexual characteristics or roles. Although the concept of feminism was defined and analysed within the model suggested by Walker & Avant, the author found that the concept became oversimplified, losing much of the richness of the literature. The author felt that, for any development of theory or practice, this analysis would have to be expanded. It is argued that their model is too restrictive as it is based on positivist philosophy which seeks to establish divisions where, in fact, there is a blurring of meaning.(ABSTRACT TRUNCATED AT 250 WORDS) PMID:8263244

  3. Advanced concepts for acceleration

    SciTech Connect

    Keefe, D.

    1986-07-01

    Selected examples of advanced accelerator concepts are reviewed. Such plasma accelerators as plasma beat wave accelerator, plasma wake field accelerator, and plasma grating accelerator are discussed particularly as examples of concepts for accelerating relativistic electrons or positrons. Also covered are the pulsed electron-beam, pulsed laser accelerator, inverse Cherenkov accelerator, inverse free-electron laser, switched radial-line accelerators, and two-beam accelerator. Advanced concepts for ion acceleration discussed include the electron ring accelerator, excitation of waves on intense electron beams, and two-wave combinations. (LEW)

  4. Qualification sous irradiation du crayon cea: de la conception des composants a l'irradiation d'assemblages en reacteur de puissance

    NASA Astrophysics Data System (ADS)

    Marin, Jean-François; Pillet, Claude; François, Bernard; Morize, Pierre; Petitgrand, Sylvie; Atabek, Rose-Marie; Houdaille, Brigitte

    1982-04-01

    Cet article résume les principaux résultats obtenus au CEA au cours des dix dernières années dans la conception, la qualification et la fabrication des différents éléments originaux constitutifs d'un assemblage de réacteur à eau pressurisée, notamment: l'oxyde UO 2 obtenu par le procédé du Double Cycle Inverse, la gaine en zircaloy 4 recris talllsée, la grille à ressort papillon, la structure à grilles coulissantes. Les etudes et essais hors-pile de comportement thermomécanique du crayon et thermohydraulique des composants de l'assemblage, les irradiations paramétriques de crayons jusqu'à une combustion massique élevée, la validation à partir d'examens aprés irradiation des principaux modèles introduits dans les calculs de conception, enfin l'introduction en réacteur prototype, puis en réacteur de puissance d'assemblages comportant ces différents éléments, constituent les principales étapes de ce développement.

  5. Low cycle fatigue

    NASA Technical Reports Server (NTRS)

    Solomon, H. D. (Editor); Kaisand, L. R. (Editor); Halford, G. R. (Editor); Leis, B. N. (Editor)

    1988-01-01

    The papers contained in this volume focus on various aspects of low cycle fatigue, including cyclic deformation, crack propagation, high-temperature low cycle fatigue, microstructural defects, multiaxial and variable amplitude loading, and life prediction. Papers are presented on the low cycle fatigue of some aluminum alloys, prediction of crack growth under creep-fatigue loading conditions, high-temperature low cycle fatigue behavior and lifetime prediction of a nickel-base ODS alloy, and an integrated approach to creep-fatigue life prediction. Other topics discussed include thermal fatigue testing of coated monocrystalline superalloys, low cycle fatigue of Al-Mg-Si alloys, and the effect of superimposed stresses at high frequency on low cycle fatigue.

  6. Les Hemorragies Gastroduodenales de Stress Chez le Brule Grave

    PubMed Central

    Siah, S.; Fouadi, F.E.; Ababou, K.; Nassim Sabah, T.; Ihrai, I.

    2008-01-01

    Summary Les Auteurs rapportent trois observations d'hémorragies gastroduodénales de stress chez le brûlé grave. Ils rappellent l'importance des mesures thérapeutiques qui doivent être prises chez le brûlé grave, comme le traitement du choc, du sepsis, des plaies et de la douleur, la nutrition entérale précoce et l'oxygénothérapie. Tout cela permet de réduire les facteurs de risque de survenue d'une hémorragie gastroduodénale de stress. PMID:21991137

  7. Automated Verification of Design Patterns with LePUS3

    NASA Technical Reports Server (NTRS)

    Nicholson, Jonathan; Gasparis, Epameinondas; Eden, Ammon H.; Kazman, Rick

    2009-01-01

    Specification and [visual] modelling languages are expected to combine strong abstraction mechanisms with rigour, scalability, and parsimony. LePUS3 is a visual, object-oriented design description language axiomatized in a decidable subset of the first-order predicate logic. We demonstrate how LePUS3 is used to formally specify a structural design pattern and prove ( verify ) whether any JavaTM 1.4 program satisfies that specification. We also show how LePUS3 specifications (charts) are composed and how they are verified fully automatically in the Two-Tier Programming Toolkit.

  8. What a Concept! Using Concept Mapping on Handheld Computers

    ERIC Educational Resources Information Center

    Royer, Regina; Royer, Jeff

    2004-01-01

    When designed properly, concept mapping activities can engage students in meaningful learning. In the process of creating concept maps, students relate new information to more general concepts already held, develop fuller understandings of those general concepts, and recognize new relationships between concepts. Students engage in these activities…

  9. [Cycling in Zagreb].

    PubMed

    Matos, Stipan; Krapac, Ladislav; Krapac, Josip

    2007-01-01

    Cycling in Zagreb, as means of urban transport inside and outside the city, has a bright past, hazy presence but a promising future. Every day, aggressive citizens who lack urban traffic culture mistreat many cyclists but also many pedestrians. Sedentary way of living, unhealthy eating habits and inadequate recreation would surely be reduced if Zagreb had a network of cycling tracks (190 cm) or lanes (80 cm). Main city roads were constructed at the beginning of the 20th century. Today, the lack of cycling tracks is particularly evident in terms of missing connections between northern and southern parts of the city. Transportation of bikes in public vehicles, parking of bikes as well as cycling along the foot of the mountains Medvednica and Zumberacko gorje is not adequately organized. Better organization is necessary not only because of the present young generation but also because of the young who will shortly become citizens of the EU, where cycling is enormously popular. Cycling tourism is not known in Zagreb, partly due to inadequate roads. The surroundings of Zagreb are more suitable for cycling tourism and attractive brochures and tourist guides offer information to tourists on bikes. Professional, acrobatic and sports cycling do not have a tradition in Zagreb and in Croatia. The same holds true for recreational cycling and indoor exercise cycling. The authors discuss the impact of popularization of cycling using print and electronic media. The role of district and local self-government in the construction and improvement of traffic roads in Zagreb is very important. It is also significant for the implementation of legal regulations that must be obeyed by all traffic participants in order to protect cyclists, the most vulnerable group of traffic participants besides passengers. Multidisciplinary action of all benevolent experts would surely increase safety and pleasure of cycling in the city and its surroundings. This would also help reduce daily stress and

  10. Imagerie Resolue dans le Temps des Photons et Neutres Metastables Emis D'une Surface Par Stimulation Electronique

    NASA Astrophysics Data System (ADS)

    Leclerc, Gregoire

    L'appareil que nous presentons ici a ete mis au point pour permettre d'accumuler des images numeriques, resolues dans le temps, de la desorption par stimulation electronique (DSE) d'ions positifs et negatifs, de photons et de neutres metastables, tout en conservant des capacites de base de diffraction d'electrons lents (DEL) et de transmission d'electrons lents (TEL). Le spectrometre comporte un monochromateur d'electrons a secteur cylindrique de 127^ circ dont l'optique de sortie permet la focalisation du faisceau d'electrons sur une large gamme d'energies. Le detecteur consiste en un empilement de galettes de microcanaux et d'une anode resistive a encodage de division de charges. La reponse spatiale du detecteur a ete calibree et plusieurs causes de non-linearite ont ete localisees et corrigees. Des methodes de correction materielle et logicielle des distorsions spatiales sont presentees. La resolution temporelle des evenements est obtenue en pulsant le faisceau d'electrons, et de facon synchrone la detection, laquelle est couplee a un micro-ordinateur. La premiere partie de ce travail est consacree a la caracterisation du spectrometre et la presentation de nombreux parametres operationnels, obtenus soit au moment de la conception, soit experimentalement. Suit la presentation de donnees de DEL et de DSE pour le systeme Ar/Pt(111) en films minces a 15K. Les sequences temporelles d'images de metastables d'Ar desorbes ont revele la presence de plusieurs populations distinctes, ayant des distributions angulaires et distributions d'energie cinetique que nous avons pu separer. Les fonctions d'excitation de l'emission de photons et de la desorption de differentes composantes de metastables, ainsi que la dependance de ces signaux sur l'epaisseur des films d'Ar, sont aussi presentees et analysees. Les techniques que nous avons developpees ont permis de cerner les mecanismes en jeu pour la desorption et la luminescence.

  11. Common tester platform concept.

    SciTech Connect

    Hurst, Michael James

    2008-05-01

    This report summarizes the results of a case study on the doctrine of a common tester platform, a concept of a standardized platform that can be applicable across the broad spectrum of testing requirements throughout the various stages of a weapons program, as well as across the various weapons programs. The common tester concept strives to define an affordable, next-generation design that will meet testing requirements with the flexibility to grow and expand; supporting the initial development stages of a weapons program through to the final production and surveillance stages. This report discusses a concept investing key leveraging technologies and operational concepts combined with prototype tester-development experiences and practical lessons learned gleaned from past weapons programs.

  12. The concept of poverty.

    PubMed

    Carney, P

    1992-06-01

    Although poverty is one of the most familiar and enduring conditions known to humanity, it is an extremely complicated concept to understand. Some researchers view it as a reaction to the stress of being poor, whereas others perceive it as a process of adapting to the condition of poverty. Historical definitions are numerous, but can be classified as relating to either lack of financial income or lower social status. Numerous factors contribute to the concept of poverty, including political, economic, social, and cultural forces. The one that has consistently had the greatest effect on the evolving concept is the passage of time, which encompasses all these forces in a very intricate manner. This author explored the evolution of the concept of poverty to identify relevant themes for consideration in the public health nursing domain. PMID:1508832

  13. Blazars: Artist Conception

    NASA Video Gallery

    What astronomers once thought were two blazar families may in fact be one, as shown in this artist's concept. Energy stored in the black hole during its salad days of intense accretion may later be...

  14. Space Station - early concept

    NASA Technical Reports Server (NTRS)

    1966-01-01

    Display model of space station concept--Manned Orbiting Research Laboratory in Saturn S-IVB Orbit configuration. Published in James R. Hansen, Spaceflight Revolution: NASA Langley Research Center From Sputnik to Apollo, (Washington: NASA, 1995).

  15. Space Station - early concept

    NASA Technical Reports Server (NTRS)

    1966-01-01

    Wind tunnel model of Manned Orbiting Research Laboratory concept on sting. Published in James R. Hansen, Spaceflight Revolution: NASA Langley Research Center From Sputnik to Apollo, (Washington: NASA, 1995).

  16. Decoding Astronomical Concepts

    ERIC Educational Resources Information Center

    Durisen, Richard H.; Pilachowski, Catherine A.

    2004-01-01

    Two astronomy professors, using the Decoding the Disciplines process, help their students use abstract theories to analyze light and to visualize the enormous scale of astronomical concepts. (Contains 5 figures.)

  17. Concepts in Change

    NASA Astrophysics Data System (ADS)

    Rusanen, Anna-Mari; Pöyhönen, Samuli

    2013-06-01

    In this article we focus on the concept of concept in conceptual change. We argue that (1) theories of higher learning must often employ two different notions of concept that should not be conflated: psychological and scientific concepts. The usages for these two notions are partly distinct and thus straightforward identification between them is unwarranted. Hence, the strong analogy between scientific theory change and individual learning should be approached with caution. In addition, we argue that (2) research in psychology and cognitive science provides a promising theoretical basis for developing explanatory mechanistic models of conceptual change. Moreover, we argue that (3) arguments against deeper integration between the fields of psychology and conceptual change are not convincing, and that recent theoretical developments in the cognitive sciences might prove indispensable in filling in the details in mechanisms of conceptual change.

  18. Solar Concepts: Teacher Notes.

    ERIC Educational Resources Information Center

    Gorham, Jonathan W.

    This volume of teacher notes describes teaching methods to support the material presented in the background text and to elaborate on basic solar concepts. Included are objectives and quizzes, teacher notes and bibliographies, and selected student projects. (Author/RE)

  19. Marned Orbital Systems Concept

    NASA Technical Reports Server (NTRS)

    1975-01-01

    Despite the indefinite postponement of the Space Station in 1972, Marshall Space Flight Center (MSFC) continued to look to the future for some type of orbital facility during the post-Skylab years. In 1975, the MSFC directed a contract with the McDonnel Douglas Aerospace Company for the Manned Orbital Systems Concept (MOSC) study. This 9-month effort examined the requirements for, and defined a cost-effective orbital facility concept capable of, supporting extended manned missions in Earth orbit. The capabilities of this concept exceeded those envisioned for the Space Shuttle and Spacelab, both of which were limited by a 7 to 30-day orbital time constraint. The MOSC's initial operating capability was to be achieved in late 1984. A crew of four would man a four-module configuration. During its five-year orbital life the MOSC would have the capability to evolve into a larger 12-to-24-man facility. This is an artist's concept of MOSC.

  20. Enquête entomologique dans le foyer historique de trypanosomose humaine africaine de Bendjé (Gabon)

    PubMed Central

    Kohagne Tongué, L.; Gounoue Kamkuimo, R.; Mengue M’eyi, P.; Kaba, D.; Louis, F.J.; Mimpfoundi, R.

    2011-01-01

    La situation de la maladie du sommeil est très peu connue au Gabon. De nombreux foyers historiques n’ont pas été prospectés depuis plus de 15 ans. Le foyer historique de Bendjé fournit régulièrement quelques cas, dépistés passivement, qui concernent le plus souvent des pêcheurs dont il est a priori difficile de déterminer le lieu probable de contamination du fait de leur grande mobilité au cours de leurs activités. La présence des hommes infectés dans ce foyer historique pourrait favoriser son réveil s’il existe un contact étroit entre les différents éléments potentiellement présents du cycle épidémiologique (homme, vecteur, trypanosome). Afin de vérifier l’existence éventuelle d’un risque trypanosomien dans ce foyer, nous y avons mené une enquête entomologique. Des pièges ont été posés dans des biotopes fréquentés par l’homme et laissés en place pendant quatre jours. Trois espèces de glossines (Glossina palpalis palpalis, G. pallicera newsteadi et G. caliginea) ont été capturées et deux espèces de trypanosomes (Trypanosoma vivax et T. brucei s.l.) identifiées par PCR. Ces résultats suggèrent l’existence d’un cycle de transmission animal. Le contact entre les hommes et les glossines est particulièrement étroit dans tous les types de site prospectés, à l’exception de la mangrove. PMID:22091460

  1. Solar activity secular cycles

    NASA Astrophysics Data System (ADS)

    Kramynin, A. P.; Mordvinov, A. V.

    2013-12-01

    Long-term variations in solar activity secular cycles have been studied using a method for the expansion of reconstructed sunspot number series Sn( t) for 11400 years in terms of natural orthogonal functions. It has been established that three expansion components describe more than 98% of all Sn( t) variations. In this case, the contribution of the first expansion component is about 92%. The averaged form of the 88year secular cycle has been determined based on the form of the first expansion coordinate function. The quasi-periodicities modulating the secular cycle have been revealed based on the time function conjugate to the first function. The quasi-periodicities modulating the secular cycle coincide with those observed in the Sn( t) series spectrum. A change in the secular cycle form and the time variations in this form are described by the second and third expansion components, the contributions of which are about 4 and 2%, respectively. The variations in the steepness of the secular cycle branches are more pronounced in the 200-year cycle, and the secular cycle amplitude varies more evidently in the 2300-year cycle.

  2. Nuclear fuel cycle costs

    SciTech Connect

    Burch, W.D.; Haire, M.J.; Rainey, R.H.

    1982-02-01

    The costs for the back-end of the nuclear fuel cycle, which were developed as part of the Nonproliferation Alternative Systems Assessment Program (NASAP), are presented. Total fuel cycle costs are given for the pressurized water reactor once-through and fuel recycle systems, and for the liquid-metal fast breeder reactor system. These calculations show that fuel cycle costs are a small part of the total power costs. For breeder reactors, fuel cycle costs are about half that of the present once-through system. The total power cost of the breeder reactor system is greater than that of light-water reactor at today's prices for uranium and enrichment.

  3. Concept analysis: resilience.

    PubMed

    Garcia-Dia, Mary Joy; DiNapoli, Jean Marie; Garcia-Ona, Leila; Jakubowski, Rita; O'Flaherty, Deirdre

    2013-12-01

    This paper will systematically analyze the concept of resilience using an integrated review of literature. The historical perspective, attributes, antecedents, and consequences of resilience will be reviewed. A theoretical and operational definition will be provided. The Walker and Avant method will be used to describe the cases. Finally, the use of concept map will capture the relationships among the attributes, antecedents, consequences, and empirical indicators through clustering and chaining. PMID:24238005

  4. Microspacecraft: A Concept

    NASA Technical Reports Server (NTRS)

    Jones, R. M.

    1992-01-01

    There is need for smaller, faster, more frequent space science missions. Smaller spacecraft may enable such missions. Technology has been developed by the United States' Department of Defense and other government agencies that can enable smaller spacecraft. This author has developed a generic concept for utilizing advanced technology to create a microspacecraft. A microspacecraft would have a mass on the order of 10 kg. This paper will present this microspacecraft concept.

  5. Overcoming: A Concept Analysis

    PubMed Central

    Brush, Barbara L.; Kirk, Keri; Gultekin, Laura; Baiardi, Janet M.

    2011-01-01

    This article provides an operational definition of overcoming as a first step in the systematic analysis of the concept. Using the method described by Walker and Avant (2005), the authors identify the attributes and characteristics of overcoming and its theoretical and practical application to nursing. Sample cases from clinical research illustrate the concept further. Further nursing research needs to test the theoretical relationships between overcoming and outcome variables. PMID:21806626

  6. The status of the HOPE concept study

    NASA Astrophysics Data System (ADS)

    Kouchiyama, Jirou; Eguchi, Akihiro

    1993-03-01

    National Space Development Agency of Japan (NASDA) has been studying an unmanned winged vehicle called the H-2 Orbiting Plane (HOPE). The HOPE will be launched by H-2 launch vehicle or H-2 derivative launch vehicle, and injected into low orbit. After a few days stay in space for access to the space station, HOPE will de-orbit and go back to a named landing site automatically. The concept of the 10-ton class vehicle launched by H-2 launch vehicle was prepared in 1988. However, its payload capability is not enough for the practical use of the space station expected at the beginning of the 21st century. Therefore, the concept of 20-ton class vehicle launched by the Solid Rocket Booster (SRB)-added H-2 launch vehicle without the second stage (Liquid Engine-5A (LE-5A) engine) was studied in 1989. This vehicle will be injected into low orbit by its own propulsion system. Its payload capability was estimated at 3 tons. In the study from 1990 to 1991, it was revealed that the reduction of the HOPE weight is the most important problem. At present, the shapes of the main wing, the orbital injection systems (reusable engine or expendable one), and the materials of the main structure (carbon/polyimide) are being studied to reduce the weight.

  7. Low-cycle thermal fatigue

    NASA Technical Reports Server (NTRS)

    Halford, G. R.

    1986-01-01

    A state-of-the-art review is presented of the field of thermal fatigue. Following a brief historical review, the concept is developed that thermal fatigue can be viewed as processes of unbalanced deformation and cracking. The unbalances refer to dissimilar mechanisms occurring in opposing halves of thermal fatigue loading and unloading cycles. Extensive data summaries are presented and results are interpreted in terms of the unbalanced processes involved. Both crack initiation and crack propagation results are summarized. Testing techniques are reviewed, and considerable discussion is given to a technique for thermal fatigue simulation, known as the bithermal fatigue test. Attention is given to the use of isothermal life prediction methods for the prediction of thermal fatigue lives. Shortcomings of isothermally-based life prediction methods are pointed out. Several examples of analyses and thermal fatigue life predictions of high technology structural components are presented. Finally, numerous dos and don'ts relative to design against thermal fatigue are presented.

  8. Anatomy of the Stirling engine cycle

    NASA Astrophysics Data System (ADS)

    Organ, A. J.

    Conditions are isolated for thermodynamic processes in two Stirling cycle machines to be identical. The conditions form the basis for the concept of 'functional similarity'. Using the similarity conditions the designer may scale the detailed gas circuit specification of a viable Stirling engine to a derivative design of different size, crankshaft speed, working fluid and pressure. The method complements, and provides an independent check of, the simulation approach to gas circuit design.

  9. [Mindfulness: A Concept Analysis].

    PubMed

    Chen, Tsai-Ling; Chou, Fan-Hao; Wang, Hsiu-Hung

    2016-04-01

    "Mindfulness" is an emerging concept in the field of healthcare. Ranging from stress relief to psychotherapy, mindfulness has been confirmed to be an effective tool to help individuals manage depression, anxiety, obsessive-compulsive disorder, and other health problems in clinical settings. Scholars currently use various definitions for mindfulness. While some of these definitions overlap, significant differences remain and a general scholarly consensus has yet to be reached. Several domestic and international studies have explored mindfulness-related interventions and their effectiveness. However, the majority of these studies have focused on the fields of clinical medicine, consultation, and education. Mindfulness has rarely been applied in clinical nursing practice and no related systematic concept analysis has been conducted. This paper conducts a concept analysis of mindfulness using the concept analysis method proposed by Walker and Avant (2011). We describe the defining characteristics of mindfulness, clarify the concept, and confirm the predisposing factors and effects of mindfulness using examples of typical cases, borderline cases, related cases, and contrary case. Findings may provide nursing staff with an understanding of the concept of mindfulness for use in clinical practice in order to help patients achieve a comfortable state of body and mind healing. PMID:27026563

  10. [Comfort: a concept analysis].

    PubMed

    Tsai, Jia-Ling; Lee, Ya-Ling; Hu, Wen-Yu

    2012-02-01

    Comfort is an important concept and core value of nursing. The defining attributes, antecedents and consequences of comfort need further analysis and exploration, even though the concept of comfort has been addressed previously in nursing literature. We employed the strategies of concept analysis as described by Walker&Avant (2005) to analyze the concept of comfort. The defining attributes of comfort include: 1) effective communication; 2) family and meaningful relationships; 3) maintaining functionality; 4) self-characteristics; 5) physical symptom relief, states, and interventions; 6) psychological, spiritual activities and states; and 7) a sense of safety and security. Antecedents consist of discomfort, distress and suffering. Consequences consist of (1) met/satisfied needs; (2) increased sense of control; (3) sense of inner peace; (4) a pleasant experience; (5) feeling cared for; (6) relief of symptoms; (7) reduced suffering; (8) decreased disequilibrium; and (9) absence of discomfort. We also outline the construction of cases, empirical references and comfort measurement tools. Analysis found comfort to have multiple dimensions and confirmed it as a clinical issue that should receive greater emphasis and valuation. Findings are hoped to increase nurse understanding of the concept of comfort and enable nurses to evaluate level of comfort and follow up on variations in such using empirical tools. Concept analysis can guide further comfort related interventions and research to benefit patients. PMID:22314653

  11. Present and future status of thermochemical cycles applied to fusion energy sources

    SciTech Connect

    Booth, L.A.; Cox, K.E.; Krakowski, R.A.; Pendergrass, J.H.

    1980-01-01

    This paper reviews the status of current research on thermochemical hydrogen production cycles and identifies the needs for advanced cycles and materials research. The Los Alamos Scientific Laboratory (LASL) bismuth sulfate thermochemical cycle is characterized, and fusion reactor blanket concepts for both inertial and magnetic confinement schemes are presented as thermal energy sources for process heat applications.

  12. Impact de la varicocèle sur le volume testiculaire et les paramètres spermatiques

    PubMed Central

    Benazzouz, Mohamed Hicham; Essatara, Younes; El Sayegh, Hachem; Iken, Ali; Benslimane, Lounis; Nouini, Yassine

    2014-01-01

    Introduction La varicocèle est une pathologie masculine fréquente dont l'incidence est encore plus importante dans dans la population des hommes infertiles. Si ses mécanismes sont à ce jour incomplètement expliqués il semble acquis que la varicocèle peut être associée a une dysfonction testiculaire avec diminution du volume testiculaire et de la concentration en spermatozoïde de l’éjaculat. Méthodes Dans un premier temps nous exposons les résultats d'une étude rétrospective sur 5 ans (de Mars 2009 à Mars 2014), réalisée au service d'urologie A de l'hôpital Ibn Sina de Rabat et ayant comme objectif d’évaluer l'impact de la varicocèle palpable sur le volume testiculaire et les paramètres spermatiques. Tous les patients inclus dans notre étude avaient une varicocèle palpable. Dans un deuxième temps, et à travers une revue de la littérature nous discutons l'impact du traitement de la varicocèle sur la fertilité. Résultats 39 patients ont été inclus dans notre étude. L’âge moyen était de 29,71 ans et la varicocèle siégeait dans 89,74% des cas du coté gauche. Une atrophie testiculaire homolatérale à la varicocèle était retrouvée dans 7% des cas alors que des anomalies du spermogramme se voyaient dans 69,23% des cas. Conclusion L'impact de la varicocèle sur l'altération des paramètres spermatiques a été clairement établi bien que sa physio pathogénie ne soit pas bien élucidée. Le traitement chirurgical de la varicocèle semble indiqué chez les hommes infertiles présentant une varicocèle clinique et une altération significative du sperme. PMID:25918574

  13. An Integrated Approach to Life Cycle Analysis

    NASA Technical Reports Server (NTRS)

    Chytka, T. M.; Brown, R. W.; Shih, A. T.; Reeves, J. D.; Dempsey, J. A.

    2006-01-01

    Life Cycle Analysis (LCA) is the evaluation of the impacts that design decisions have on a system and provides a framework for identifying and evaluating design benefits and burdens associated with the life cycles of space transportation systems from a "cradle-to-grave" approach. Sometimes called life cycle assessment, life cycle approach, or "cradle to grave analysis", it represents a rapidly emerging family of tools and techniques designed to be a decision support methodology and aid in the development of sustainable systems. The implementation of a Life Cycle Analysis can vary and may take many forms; from global system-level uncertainty-centered analysis to the assessment of individualized discriminatory metrics. This paper will focus on a proven LCA methodology developed by the Systems Analysis and Concepts Directorate (SACD) at NASA Langley Research Center to quantify and assess key LCA discriminatory metrics, in particular affordability, reliability, maintainability, and operability. This paper will address issues inherent in Life Cycle Analysis including direct impacts, such as system development cost and crew safety, as well as indirect impacts, which often take the form of coupled metrics (i.e., the cost of system unreliability). Since LCA deals with the analysis of space vehicle system conceptual designs, it is imperative to stress that the goal of LCA is not to arrive at the answer but, rather, to provide important inputs to a broader strategic planning process, allowing the managers to make risk-informed decisions, and increase the likelihood of meeting mission success criteria.

  14. Cycle life versus depth of discharge update on modeling studies. [Nickel-Hydrogen Batteries

    NASA Technical Reports Server (NTRS)

    Thaller, Lawrence H.

    1994-01-01

    The topics are presented in viewgraph form and cycle life vs. depth of discharge data for the following are presented: data as of three years ago; Air Force/Crane-Fuhr-Smithrick; Ken Fuhr's Data; Air Force/Crane Data; Eagle-Pitcher Data; Steve Schiffer's Data; John Smithrick's Data; temperature effects; and E-P, Yardney, and Hughes 26% Data. Other topics covered include the following: LeRC cycling tests of Yardney Space Station Cells; general statements; general observations; two different models of cycle life vs. depth of discharge; and other degradation modes.

  15. Development status of LE-7 fuel turbopump

    NASA Astrophysics Data System (ADS)

    Nakano, T.; Nagao, R.; Ohta, T.; Warashina, S.; Watanabe, H.; Oguchi, H.

    The liquid hydrogen turbopump (LH2 T/P) for the LE-7 engine has been developed since 1984. The component PDR was held in June 1988 and the basic troubles occurred at the development test were solved. Next, the component CDR-1 was held in December 1989 in order to feed back the test results of prototype LH2 T/P model to the design of qualification phase T/P. So, the production of these turbopumps was admitted. Recently, the component CDR-2 was held in February 1992 to reflect the counterparts adopted for some troubles (impeller and turbine blade cracks and so on) in long-time engine tests to the design of qualification phase T/P. In the qualification phase, the hydraulic characteristics and strength in the engine operating range were examined at the LH2 T/P component test, and its endurance confirmed at the engine tests. The LH2 turbopump component test was held at NASDA Kakuda and the engine test at Tashiro and Tanegashima. This paper describes the development status of LH2 T/P, containing the design description and the content of some troubles and its counterplans.

  16. L'astronomie dans le monde

    NASA Astrophysics Data System (ADS)

    Manfroid, J.

    2007-09-01

    Anions interstellaires; S Orionis; Altaîr; Courants stellaires; Etoiles jeunes; 2MASSW J1207334-393254; Alpha Andromède; Etoiles à neutrons (1); LH54-425; AGNs invisibles; Deux supernovae; Les GRBs seon Swift; Peser les trous noirs; Formation de trous noirs; Trou noir; ondes gravitationnelles : Virgo entre dans sa phase d'exploitation scientifique; Amas de galaxies actifs; Amas de galaxies; Galaxies actives d'amas; L'univers statique: le retour; Macho; Exoplanètes; Exoplanètes habitables?; Exoplanètes habitables? (suite); Une année d'un an; Une année de 31 heures; Valse des Jupiters; Disque de HD 15115; Impact majeur; Planètes isolées; Super-Jupiter; Impact et mini-extinction; L'effet Pioneer; Toungouska; Spéléo martienne; Autres lunes dactives; Encelade; Hypérion; Pluton dépassé; Satellites d'Uranus; Titan

  17. Reusable thermal cycling clamp

    NASA Technical Reports Server (NTRS)

    Debnam, W. J., Jr.; Fripp, A. L.; Crouch, R. K. (Inventor)

    1985-01-01

    A reusable metal clamp for retaining a fused quartz ampoule during temperature cycling in the range of 20 deg C to 1000 deg C is described. A compressible graphite foil having a high radial coefficient of thermal expansion is interposed between the fused quartz ampoule and metal clamp to maintain a snug fit between these components at all temperature levels in the cycle.

  18. Seeing the Carbon Cycle

    ERIC Educational Resources Information Center

    Drouin, Pamela; Welty, David J.; Repeta, Daniel; Engle-Belknap, Cheryl A.; Cramer, Catherine; Frashure, Kim; Chen, Robert

    2006-01-01

    In this article, the authors present a classroom experiment that was developed to introduce middle school learners to the carbon cycle. The experiment deals with transfer of CO[subscript 2] between liquid reservoirs and the effect CO[subscript 2] has on algae growth. It allows students to observe the influence of the carbon cycle on algae growth,…

  19. The Oxygen Cycle.

    ERIC Educational Resources Information Center

    Swant, Gary D.

    Produced for primary grades, this booklet provides study of the oxygen-carbon dioxide cycle in nature. Line drawings, a minimum amount of narrative, and a glossary of terms make up its content. The booklet is designed to be used as reading material, a coloring book, or for dramatic arts with students acting out parts of the cycle. This work was…

  20. Rock Cycle Roulette.

    ERIC Educational Resources Information Center

    Schmidt, Stan M.; Palmer, Courtney

    2000-01-01

    Introduces an activity on the rock cycle. Sets 11 stages representing the transitions of an earth material in the rock cycle. Builds six-sided die for each station, and students move to the stations depending on the rolling side of the die. Evaluates students by discussing several questions in the classroom. Provides instructional information for…

  1. Measuring Cycling Effort.

    ERIC Educational Resources Information Center

    Jahnke, Thomas; Hamson, Mike

    1999-01-01

    Investigates the basic mechanics of cycling with a simple reckoning of how much effort is needed from the cyclist. The work done by the cyclist is quantified when the ride is on the flat and also when pedaling uphill. Proves that by making use of the available gears on a mountain bike, cycling uphill can be accomplished without pain. (Author/ASK)

  2. The carbon cycle revisited

    NASA Technical Reports Server (NTRS)

    Bolin, Bert; Fung, Inez

    1992-01-01

    Discussions during the Global Change Institute indicated a need to present, in some detail and as accurately as possible, our present knowledge about the carbon cycle, the uncertainties in this knowledge, and the reasons for these uncertainties. We discuss basic issues of internal consistency within the carbon cycle, and end by summarizing the key unknowns.

  3. Family Life Cycle: 1980.

    ERIC Educational Resources Information Center

    Norton, Arthur J.

    1983-01-01

    Used data from a 1980 national sample survey to show differences in the timing of major family life-cycle events according to age, social and economic characteristics, and marital history. Results suggest that age generational differences, more than any other factor, influence timing of life-cycle events. (Author/JAC)

  4. Power Plant Cycling Costs

    SciTech Connect

    Kumar, N.; Besuner, P.; Lefton, S.; Agan, D.; Hilleman, D.

    2012-07-01

    This report provides a detailed review of the most up to date data available on power plant cycling costs. The primary objective of this report is to increase awareness of power plant cycling cost, the use of these costs in renewable integration studies and to stimulate debate between policymakers, system dispatchers, plant personnel and power utilities.

  5. Teaching the Krebs Cycle.

    ERIC Educational Resources Information Center

    Akeroyd, F. Michael

    1983-01-01

    Outlines a simple but rigorous treatment of the Krebs Cycle suitable for A-level Biology students. The importance of the addition of water molecules in various stages of the cycle is stressed as well as the removal of hydrogen atoms by the oxidizing enzymes. (JN)

  6. Le Conte's sparrows breeding in Conservation Reserve Program fields: precipitation and patterns of population change

    USGS Publications Warehouse

    Igl, L.D.; Johnson, D.H.

    1999-01-01

    The climate of the North American Great Plains is highly dynamic, with great year-to-year variability in precipitation and periodic, often extreme, wet and dry cycles (Bragg 1995). Drought is a major force of ecological disturbance on the Great Plains and has played a key role in directing the evolution of the grassland biota of this region (Knopf and Samson 1997). Although grassland birds may differ in their responses to enviromenental variations (Rotenberry and Wiens 1991), climatic variability and concomitant unpredictability of resources strongly influence populations of grassland birds across space and time (Wiens 1974, 1986; Cody 1985). Not surprisingly, breeding bird populations on the Great Plains are highly dynamic, exhibiting considerable annual variation in composition, abundance, and distribution (Johnson and Grier 1988, George et al. 1992, Zimmerman 1992, Igl and Johnson 1997). Recently, interest in grassland birds has increased with the recognition that many species are declining both continentally (Droege and Sauer 1994) and globally (Goriup 1988). Identification of the specific factors associated with grassland bird declines in North America, however, remains largely enigmatic (Herkert 1997), and it is complicated by the considerable annual fluctuations in grassland bird distribution and abundance (Igl and Johnson 1997). Although there is evidence that land-use changes on the breeding grounds may have contributed to grassland bird declines (e.g., Igl and Johnson 1997), there also is an indication that long-term drought conditions may have influenced recent population changes of some breeding birds on the Great Plains (Droege and Sauer 1989, Peterjohn and Sauer 1993, Bethke and Nudds 1995, Igl and Johnson 1997). Le Conte's Sparrow (Ammodramus leconteii) is a secretive grassland bird that breeds in central and southern Canada and the northcentral United States (Murray 1969). It winters primarily in the southern United States (Peterson 1980, 1990

  7. A model for life cycle records management

    SciTech Connect

    Tayfun, A.C.; Gibson, S.

    1996-10-01

    The primary objective of this paper is to update an old Records Management concept; the management of records according to the records life cycle. Accordingly, the authors are presenting a new version of the Records Management life cycle model and its associated elements. The basic concept is that every record progresses through three phases; a record is created, is used and maintained, and dispositioned. In this presentation, the authors update the very old straight line model and the more current circular model with a new model that essentially combines the two. The model portrays Records Management as having a distinct straight-line beginning, a circular use and maintenance phase, and a distinct straight-line end. The presentation maps Records Management Program elements and activities against the phases depicted in the model. The authors believe that this new records life cycle model is an enhanced physical representation of the process. This presentation is designed to help put all of the specialized Records Management topics that participants have heard about during the conference in the perspective of the records life cycle.

  8. A comparison of single-cycle versus multi-cycle proof testing strategies

    NASA Technical Reports Server (NTRS)

    Hudak, Stephen J., Jr.; Russell, Dale A.

    1988-01-01

    Proof testing was a useful supplement to conventional nondestructive evaluation (NDE) of space shuttle main engine (SSME) components. Since many of these components involve thin sections and high toughness materials, such as Inconel 718, conventional single-cycle proof test logic is not applicable due to the propensity for stable crack growth during the proof tests. Experience with five-cycle proof testing of SSME components is summarized and a framework is outlined for understanding multi-cycle proof testing using the fracture mechanics concept of a resistance curve. Extreme value statistics are also used to propose an empirical approach to compare the advantages and disadvantages of single- versus multi-cycle proof testing. The importance of the initial flaw size distribution and specimen thickness in such a comparison is also discussed.

  9. Development of the Hybrid Jt-Expander Cycle for NG Liquefaction Cycle

    NASA Astrophysics Data System (ADS)

    Baek, S.; Hwang, G.; Jeong, S.

    2010-04-01

    Two liquefaction cycles for LNG (liquefied natural gas) production are compared in this paper. One is a well known MR (mixed refrigerant) JT cycle with two phase separators and four heat exchangers. Another one is the novel concept of hybrid cycle, which is to replace the last stage JT expansion with a turbine expander. The inlet flow to the turbine expander is deliberately warmed up by NG (natural gas) stream to guarantee superheated vapor phase and increase useful work. The turbine expander is to extract pressure exergy and reduce entropy generation by producing work and alleviating work requirement in the compressor. This paper describes the detailed processes of hybrid JT-expander cycle and the quantitative comparison results by HYSYS simulation under some realistic physical constraints.

  10. MHD integrated topping cycle project

    NASA Astrophysics Data System (ADS)

    1992-01-01

    The overall objective of the project is to design and construct prototypical hardware for an integrated MHD topping cycle, and conduct long duration proof-of-concept tests of integrated system at the US DOE Component Development and Integration Facility in Butte, Montana. The results of the long duration tests will augment the existing engineering design data base on MHD power train reliability, availability, maintainability, and performance, and will serve as a basis for scaling up the topping cycle design to the next level of development, an early commercial scale power plant retrofit. The components of the MHD power train to be designed, fabricated, and tested include: A slagging coal combustor with a rated capacity of 50 MW thermal input, capable of operation with an Eastern (Illinois no. 6) or Western (Montana Rosebud) coal, a segmented supersonic nozzle, a supersonic MHD channel capable of generating at least 1.5 MW of electrical power, a segmented supersonic diffuser section to interface the channel with existing facility quench and exhaust systems, a complete set of current control circuits for local diagonal current control along the channel, and a set of current consolidation circuits to interface the channel with the existing facility inverter.

  11. Externally fired combined cycle demonstration

    SciTech Connect

    Orozco, N.J.; Young, S.; LaHaye, P.G.; Strom-Olsen, J.; Seger, J.L.; Pickup, H.

    1995-11-01

    Externally Fired Combined Cycles (EFCCs) can increase the amount of electricity produced from ash bearing fuels up to 40%, with overall powerplant efficiencies in excess of 45%. Achieving such high efficiencies requires high temperature-high pressure air heaters capable of driving modern gas turbines from gas streams containing the products of coal combustion. A pilot plant has been constructed in Kennebunk, Maine to provide proof of concept and evaluation of system components. Tests using pulverized Western Pennsylvania bituminous coal have been carried out since April, 1995. The ceramic air heater extracts energy from the products of coal combustion to power a gas turbine. This air heater has operated at gas inlet temperatures over 1,095 C and pressures over 7.0 atm without damage to the ceramic tube string components. Stable gas turbine operation has been achieved with energy input from the air heater and a supplementary gas fired combustor. Efforts are underway to fire the cycle on coal only, and to increase the duration of the test runs. Air heater improvements are being implemented and evaluated. These improvements include installation of a second pass of ceramic tubes and evaluation of corrosion resistant coatings on the ceramic tubes.

  12. MHD Integrated Topping Cycle Project

    SciTech Connect

    Not Available

    1992-03-01

    The Magnetohydrodynamics (MHD) Integrated Topping Cycle (ITC) Project represents the culmination of the proof-of-concept (POC) development stage in the US Department of Energy (DOE) program to advance MHD technology to early commercial development stage utility power applications. The project is a joint effort, combining the skills of three topping cycle component developers: TRW, Avco/TDS, and Westinghouse. TRW, the prime contractor and system integrator, is responsible for the 50 thermal megawatt (50 MW{sub t}) slagging coal combustion subsystem. Avco/TDS is responsible for the MHD channel subsystem (nozzle, channel, diffuser, and power conditioning circuits), and Westinghouse is responsible for the current consolidation subsystem. The ITC Project will advance the state-of-the-art in MHD power systems with the design, construction, and integrated testing of 50 MW{sub t} power train components which are prototypical of the equipment that will be used in an early commercial scale MHD utility retrofit. Long duration testing of the integrated power train at the Component Development and Integration Facility (CDIF) in Butte, Montana will be performed, so that by the early 1990's, an engineering data base on the reliability, availability, maintainability and performance of the system will be available to allow scaleup of the prototypical designs to the next development level. This Sixteenth Quarterly Technical Progress Report covers the period May 1, 1991 to July 31, 1991.

  13. MHD Integrated Topping Cycle Project

    SciTech Connect

    Not Available

    1992-01-01

    The overall objective of the project is to design and construct prototypical hardware for an integrated MHD topping cycle, and conduct long duration proof-of-concept tests of integrated system at the US DOE Component Development and Integration Facility in Butte, Montana. The results of the long duration tests will augment the existing engineering design data base on MHD power train reliability, availability, maintainability, and performance, and will serve as a basis for scaling up the topping cycle design to the next level of development, an early commercial scale power plant retrofit. The components of the MHD power train to be designed, fabricated, and tested include: A slagging coal combustor with a rated capacity of 50 MW thermal input, capable of operation with an Eastern (Illinois {number sign}6) or Western (Montana Rosebud) coal, a segmented supersonic nozzle, a supersonic MHD channel capable of generating at least 1.5 MW of electrical power, a segmented supersonic diffuser section to interface the channel with existing facility quench and exhaust systems, a complete set of current control circuits for local diagonal current control along the channel, and a set of current consolidation circuits to interface the channel with the existing facility inverter.

  14. Predicting the Sunspot Cycle

    NASA Technical Reports Server (NTRS)

    Hathaway, David H.

    2009-01-01

    The 11-year sunspot cycle was discovered by an amateur astronomer in 1844. Visual and photographic observations of sunspots have been made by both amateurs and professionals over the last 400 years. These observations provide key statistical information about the sunspot cycle that do allow for predictions of future activity. However, sunspots and the sunspot cycle are magnetic in nature. For the last 100 years these magnetic measurements have been acquired and used exclusively by professional astronomers to gain new information about the nature of the solar activity cycle. Recently, magnetic dynamo models have evolved to the stage where they can assimilate past data and provide predictions. With the advent of the Internet and open data policies, amateurs now have equal access to the same data used by professionals and equal opportunities to contribute (but, alas, without pay). This talk will describe some of the more useful prediction techniques and reveal what they say about the intensity of the upcoming sunspot cycle.

  15. Food and medical sample freezer kit concept for Shuttle

    NASA Technical Reports Server (NTRS)

    Copeland, R. J.; Jaax, J. R.; Proctor, B. W.

    1977-01-01

    A variety of food and storage of samples can be provided by a Space Shuttle Orbiter Freezer Kit. The proposed concept is an integrated package consisting of four -23 C (-10 F) storage compartments and a Stirling cycle refrigeration unit. The Stirling cycle mechanical refrigeration was selected over alternative systems for superior efficiency and safety. The trade-offs and a conceptual design of the system are presented.

  16. Concepts For An EO Land Convoy Mission

    NASA Astrophysics Data System (ADS)

    Cutter, M. A.; Eves, S.; Remedios, J.; Humpage, N.; Hall, D.; Regan, A.

    2013-12-01

    ESA are undertaking three studies investigating possible synergistic satellite missions flying in formation with the operational Copernicus Sentinel missions and/or the METOP satellites. These three studies are focussed on:- a) ocean and ice b) land c) atmosphere Surrey Satellite Technology Ltd (SSTL), the University of Leicester and Astrium Ltd are undertaking the second of these studies into the synergetic observation by missions flying in formation with European operational missions, focusing on the land theme. The aim of the study is to identify and develop, (through systematic analysis), potential innovative Earth science objectives and novel applications and services that could be made possible by flying additional satellites, (possibly of small-class type), in constellation or formation with one or more already deployed or firmly planned European operational missions, with an emphasis on the Sentinel missions, but without excluding other possibilities. In the long-term, the project aims at stimulating the development of novel, (smaller), mission concepts in Europe that may exploit new and existing European operational capacity in order to address in a cost effective manner new scientific objectives and applications. One possible route of exploitation would be via the proposed Small Mission Initiative (SMI) that may be initiated under the ESA Earth Explorer Observation Programme (EOEP). The following ESA science priority areas have been highlighted during the study [1]:- - The water cycle - The carbon cycle - Terrestrial ecosystems - Biodiversity - Land use and land use cover - Human population dynamics The study team have identified the science gaps that might be addressed by a "convoy" mission flying with the Copernicus Sentinel satellites, identified the candidate mission concepts and provided recommendations regarding the most promising concepts from a list of candidates. These recommendations provided the basis of a selection process performed by ESA

  17. Transmaxillary Sinus Approach for Le Fort II Osteotomy

    PubMed Central

    Fukawa, Toshihiko; Hirakawa, Takashi; Satake, Toshihiko; Maegawa, Jiro

    2016-01-01

    Summary: The Le Fort II osteotomy is a relatively rare operation. The posterior wall osteotomy of the maxillary sinus (MS) is often difficult for Le Fort III. We developed the transmaxillary sinus approach (TSA) for the Le Fort II osteotomy that cuts the posterior wall of the MS directly. This report illustrates this easy-to-use procedure for the Le Fort II osteotomy in syndromic craniosynostosis. This procedure was performed in an 18-year-old patient with Apert syndrome and a 15-year-old patient with Pfeiffer syndrome. The thin anterior walls of the MS were removed through an intraoral approach to look inside the MS. Then, the posterior walls were cut by chisel under direct vision using light. The other osteotomy was performed as usual. Distraction osteogenesis with internal and external devices was used in combination. The advantages of TSA are the direct posterior wall osteotomy of the MS with no down fracture and minimal invasiveness to the mucosa of the MS under direct vision. However, the disadvantage is that TSA becomes a blind procedure in a case with no MS or hypoplasia. We developed the TSA for the Le Fort II osteotomy, which could provide direct observation and perform the posterior wall osteotomy of the MS without down fracture. We believe that TSA is an effective surgical procedure for the Le Fort II osteotomy. PMID:27014548

  18. Transmaxillary Sinus Approach for Le Fort II Osteotomy.

    PubMed

    Kobayashi, Shinji; Fukawa, Toshihiko; Hirakawa, Takashi; Satake, Toshihiko; Maegawa, Jiro

    2016-02-01

    The Le Fort II osteotomy is a relatively rare operation. The posterior wall osteotomy of the maxillary sinus (MS) is often difficult for Le Fort III. We developed the transmaxillary sinus approach (TSA) for the Le Fort II osteotomy that cuts the posterior wall of the MS directly. This report illustrates this easy-to-use procedure for the Le Fort II osteotomy in syndromic craniosynostosis. This procedure was performed in an 18-year-old patient with Apert syndrome and a 15-year-old patient with Pfeiffer syndrome. The thin anterior walls of the MS were removed through an intraoral approach to look inside the MS. Then, the posterior walls were cut by chisel under direct vision using light. The other osteotomy was performed as usual. Distraction osteogenesis with internal and external devices was used in combination. The advantages of TSA are the direct posterior wall osteotomy of the MS with no down fracture and minimal invasiveness to the mucosa of the MS under direct vision. However, the disadvantage is that TSA becomes a blind procedure in a case with no MS or hypoplasia. We developed the TSA for the Le Fort II osteotomy, which could provide direct observation and perform the posterior wall osteotomy of the MS without down fracture. We believe that TSA is an effective surgical procedure for the Le Fort II osteotomy. PMID:27014548

  19. Three-dimensional Nasolabial Morphologic Alterations Following Le Fort I

    PubMed Central

    DeSesa, Christopher R.; Metzler, Philip; Sawh-Martinez, Rajendra

    2016-01-01

    Background: Le Fort I osteotomy imparts significant changes to the nasolabial region. Past studies have relied on 2-dimensional data and have not delineated differences among various Le Fort I subtypes. The purpose of this study is to 3-dimensionally analyze Le Fort I–induced nasal and lip changes comparing advancement alone versus widening alone [surgically assisted maxillary expansion (SAME)] versus advancement and widening. We hypothesize that the combination of maxillary advancement with widening will result in the most profound changes. Methods: A retrospective cohort study was performed. Included Le Fort I patients were grouped as: (1) nonsegmental straight advancement, (2) widening without advancement, and (3) segmental advancement and widening. Pre- and postoperative 3-dimensional photogrammetry (Canfield) were analyzed. Anthropometric landmarks were placed and measured by 2 independent observers. Statistics involved both paired and unpaired t tests (significance = P < 0.05). Results: One hundred eight photogrammetric data sets were analyzed, including 46 single-piece, 26 SAME, and 36 segmental. Significant postoperative nasal changes were observed within each intragroup analysis. The most dramatic changes were seen after segmental Le Fort I with advancement and widening, which included alar base width, alar width, nostril width, and soft triangle angle, all P < 0.05. Conclusions: Le Fort I osteotomy results in significant alteration of the nasolabial morphology. This is the first study to 3-dimensionally analyze nasal changes that occur comparing maxillary advancement alone versus widening alone (SAME) versus advancement with widening. These objective data permit improved patient counseling and surgical planning. PMID:27622116

  20. Lactobacillus equigenerosi Strain Le1 Invades Equine Epithelial Cells

    PubMed Central

    Botha, Marlie; Botes, Marelize; Loos, Ben; Smith, Carine

    2012-01-01

    Lactobacillus equigenerosi strain Le1, a natural inhabitant of the equine gastrointestinal tract, survived pH 3.0 and incubation in the presence of 1.5% (wt/vol) bile salts for at least 2 h. Strain Le1 showed 8% cell surface hydrophobicity, 60% auto-aggregation, and 47% coaggregation with Clostridium difficile C6. Only 1% of the cells adhered to viable buccal epithelial cells and invaded the cells within 20 min after contact. Preincubation of strain Le1 in a buffer containing pronase prevented adhesion to viable epithelial cells. Preincubation in a pepsin buffer delayed invasion from 20 min to 1 h. Strain Le1 did not adhere to nonviable epithelial cells. Administration of L. equigenerosi Le1 (1 × 109 CFU per 50 kg body weight) to healthy horses did not increase white blood cell numbers. Differential white blood cell counts and aspartate aminotransferase levels remained constant. Glucose, lactate, cholesterol, and urea levels remained constant during administration with L. equigenerosi Le1 but decreased during the week after administration. PMID:22504808

  1. Searching the animal psyche with Charles Le Brun.

    PubMed

    Cohen, Sarah R

    2010-07-01

    Around 1670 the French court painter and Academician Charles Le Brun produced a series of drawings featuring naturalistic animal heads, as well as imaginary heads in which he refashioned various nonhuman animal species to make humanoid physiognomies. What were the purpose and significance of these unusual works? I argue that they show Le Brun's interest in what we today would call animal psychology: focusing upon the sensory organs and their connections with the animal's brain, Le Brun studied his animals as conscious protagonists of the natural realm. One source that may have served him in this project was Marin Cureau de La Chambre's De la Connoissance des bestes of 1645, in which the physician argued that animals possess a conscious soul grounded in the senses. However, Le Brun's animal-humans have no clear place in the artist's taxonomy--nor, indeed, in any seventeenth-century understandings of species. It is rather John Locke, at his most skeptical, who offers the best parallel in the realm of natural philosophy to Le Brun's unsettling animal-humans. Probably without meaning to, Le Brun demonstrated through his eerie, boundary-crossing creatures the limits of visual classification. PMID:20853815

  2. The Chlamydomonas Cell Cycle

    PubMed Central

    Cross, Frederick R.; Umen, James G.

    2015-01-01

    The position of Chlamydomonas within the eukaryotic phylogeny makes it a unique model in at least two important ways: as a representative of the critically important, early-diverging lineage leading to plants, and as a microbe retaining important features of the last eukaryotic common ancestor (LECA) that have been lost in the highly studied yeast lineages. Its cell biology has been studied for many decades, and it has well-developed experimental genetic tools, both classical (Mendelian) and molecular. Unlike land plants, it is a haploid with very few gene duplicates, making it ideal for loss-of-function genetic studies. The Chlamydomonas cell cycle has a striking temporal and functional separation between cell growth and rapid cell divisions, probably connected to the interplay between diurnal cycles that drive photosynthetic cell growth with the cell division cycle; it also exhibits a highly choreographed interaction between the cell cycle and its centriole/basal body/flagellar cycle. Here we review the current status of studies of the Chlamydomonas cell cycle. We begin with an overview of cell cycle control in the well-studied yeast and animal systems, which has yielded a canonical, well-supported model. We discuss briefly what is known about similarities and differences in plant cell cycle control compared to this model. We next review the cytology and cell biology of the multiple fission cell cycle of Chlamydomonas. Lastly we review recent genetic approaches and insights into Chlamydomonas cell cycle regulation that have been enabled by a new generation of genomics-based tools. PMID:25690512

  3. A Key Concept: Spatial Organization

    ERIC Educational Resources Information Center

    Kostrowicki, Jerzy

    1975-01-01

    The application of geography to spatial planning is discussed. Concepts presented include the regional concept, the typological concept, and spatial structure, spatial processes, and spatial organization. For address of journal see SO 504 028. (Author/RM)

  4. Concept Analysis: Music Therapy.

    PubMed

    Murrock, Carolyn J; Bekhet, Abir K

    2016-01-01

    Down through the ages, music has been universally valued for its therapeutic properties based on the psychological and physiological responses in humans. However, the underlying mechanisms of the psychological and physiological responses to music have been poorly identified and defined. Without clarification, a concept can be misused, thereby diminishing its importance for application to nursing research and practice. The purpose of this article was for the clarification of the concept of music therapy based on Walker and Avant's concept analysis strategy. A review of recent nursing and health-related literature covering the years 2007-2014 was performed on the concepts of music, music therapy, preferred music, and individualized music. As a result of the search, the attributes, antecedents, and consequences of music therapy were identified, defined, and used to develop a conceptual model of music therapy. The conceptual model of music therapy provides direction for developing music interventions for nursing research and practice to be tested in various settings to improve various patient outcomes. Based on Walker and Avant's concept analysis strategy, model and contrary cases are included. Implications for future nursing research and practice to use the psychological and physiological responses to music therapy are discussed. PMID:27024999

  5. Which 100-kyr Cycle?

    NASA Astrophysics Data System (ADS)

    Berger, A.; Loutre, M. F.; Mélice, J. L.

    The origin of all the fundamental frequencies characterising the long term variations of the astronomical parameters has been identified. This allows to discuss their inter- relationship and possible changes in times. Different sources for the so-called 100-kyr cycle have been found in the astronomical parameters and in the insolation itself. The most popular 100-kyr cycle is certainly the eccentricity one. Actually, the periods of the most important spectral components of e used in Berger (1978) are 412 885, 14 945, 123 297, 99 590 and 131 248 yr. Instability of the resulting average 100-kyr cy- cle has been shown related to the ~ 400-kyr cycle. The derivative of eccentricity is definitely showing a spectrum dominated by the 100-kyr cycle with the same spectral components as e itself. The inclination of the Earth orbital plane on the ecliptic does not display any 100-kyr cycle, but it is not the case for its inclination on the reference plane for which cycles of 98 046 and 107 478 years appear. Finally the frequency modulation of obliquity is characterised by cycles 171 kyr and 97 kyr long. For inso- lation, it is known that there is only a very weak signal around 100-kyr coming from e itself. However, if we consider the seasonal cycle at the equator, its amplitude varies with cycles of 400 kyr, 100 kyr, 41 kyr, 10 kyr and 5 kyr, all related to e. Although all these cycles are close to the 100 kyr cycle found in geological data, the origin of this kind of cycle can be best identified by comparing the proxy record to the re- sponse of the climate system to the astronomical forcing. This forcing signal which contains, in one way or another, the astronomical characteristics mentioned above is, at least, partly distorted and transformed, a modification which can only be estimated through climate models. Such a climate model has been developed in the early 80Ss in Louvain-la-Neuve and used since to simulate the last and next glacial-interglacial cycles.

  6. Investigation of Exoskeletal Engine Propulsion System Concept

    NASA Technical Reports Server (NTRS)

    Roche, Joseph M.; Palac, Donald T.; Hunter, James E.; Myers, David E.; Snyder, Christopher A.; Kosareo, Daniel N.; McCurdy, David R.; Dougherty, Kevin T.

    2005-01-01

    An innovative approach to gas turbine design involves mounting compressor and turbine blades to an outer rotating shell. Designated the exoskeletal engine, compression (preferable to tension for high-temperature ceramic materials, generally) becomes the dominant blade force. Exoskeletal engine feasibility lies in the structural and mechanical design (as opposed to cycle or aerothermodynamic design), so this study focused on the development and assessment of a structural-mechanical exoskeletal concept using the Rolls-Royce AE3007 regional airliner all-axial turbofan as a baseline. The effort was further limited to the definition of an exoskeletal high-pressure spool concept, where the major structural and thermal challenges are represented. The mass of the high-pressure spool was calculated and compared with the mass of AE3007 engine components. It was found that the exoskeletal engine rotating components can be significantly lighter than the rotating components of a conventional engine. However, bearing technology development is required, since the mass of existing bearing systems would exceed rotating machinery mass savings. It is recommended that once bearing technology is sufficiently advanced, a "clean sheet" preliminary design of an exoskeletal system be accomplished to better quantify the potential for the exoskeletal concept to deliver benefits in mass, structural efficiency, and cycle design flexibility.

  7. Vicarious traumatization: concept analysis.

    PubMed

    Tabor, Pamela Diane

    2011-12-01

    There is growing knowledge of the effects of stress on professionals, including various negative symptoms that may mirror the biopsychosocial effects exhibited by the victims of trauma. Multiple concepts including burn out, compassion fatigue, post-traumatic stress disorder (PTSD), and secondary traumatic stress, are terms that have been incorrectly interchanged with the term vicarious traumatization (VT). Clarity of vicarious victimization and understanding contributing factors is imperative in order to facilitate future research and implement timely and effective interventions, as well as sculpt evidence based practice. This concept anaylsis, complete with a concept map, discusses VT; related terminology; symptomology; prevention and relevant interventions; and discusses opportunities for personal/professional growth for nurses and especially forensic nurses working with victims of violence. PMID:22123041

  8. Telepresence work system concepts

    NASA Technical Reports Server (NTRS)

    Jenkins, L. M.

    1985-01-01

    Telepresence has been used in the context of the ultimate in remote manipulation where the operator is provided with the sensory feedback and control to perform highly dexterous tasks. The concept of a Telepresence Work Station (TWS) for operation in space is described. System requirements, concepts, and a development approach are discussed. The TWS has the potential for application on the Space Shuttle, on the Orbit Maneuver Vehicle, on an Orbit Transfer Vehicle, and on the Space Station. The TWS function is to perform satellite servicing tasks and construction and assembly operations in the buildup of large spacecraft. The basic concept is a pair of dexterous arms controlled from a remote station by an operation with feedback. It may be evolved through levels of supervisory control to a smart adaptive robotic system.

  9. Robust Rocket Engine Concept

    NASA Technical Reports Server (NTRS)

    Lorenzo, Carl F.

    1995-01-01

    The potential for a revolutionary step in the durability of reusable rocket engines is made possible by the combination of several emerging technologies. The recent creation and analytical demonstration of life extending (or damage mitigating) control technology enables rapid rocket engine transients with minimum fatigue and creep damage. This technology has been further enhanced by the formulation of very simple but conservative continuum damage models. These new ideas when combined with recent advances in multidisciplinary optimization provide the potential for a large (revolutionary) step in reusable rocket engine durability. This concept has been named the robust rocket engine concept (RREC) and is the basic contribution of this paper. The concept also includes consideration of design innovations to minimize critical point damage.

  10. Basic concepts of depression

    PubMed Central

    Paykel, Eugene S.

    2008-01-01

    This paper reviews concepts of depression, including history and classification. The original broad concept of melancholia included all forms of quiet insanity. The term depression began to appear in the nineteenth century as did the modern concept of affective disorders, with the core disturbance now viewed as one of mood. The 1930s saw the introduction of defined criteria into official diagnostic schemes. The modern separation into unipolar and bipolar disorder was introduced following empirical research by Angst and Perris in the 1960s. The partially overlapping distinctions between psychotic and neurotic depression, and between endogenous and reactive depression, started to generate debate in the 1920s, with considerable multivariate research in the 1960s. The symptom element in endogenous depression currently survives in melancholia or somatic syndrome. Life stress is common in various depressive pictures. Dysthymia, a valuable diagnosis, represents a form of what was regarded earlier as neurotic depression. Other subtypes are also discussed. PMID:18979941

  11. Mars rover concept development

    NASA Technical Reports Server (NTRS)

    Mctamaney, Louis S.; Douglas, Barry D.; Harmon, Scott Y.

    1989-01-01

    A structured study effort to develop an extensive, innovative set of mobility and navigation concepts for a planetary exploration vehicle along with the concomitant value system and evaluation tools is presented. A further objective is to submit these concepts to a rigorous, structured evaluation process to derive the most promising candidate systems. To support the evaluation process, a three-layer computer model of the Martian surface was developed, based on the 1/64 deg Digital Elevation Model (DEM) of Mars. Local surface roughness based on measured Martian slope distribution and power spectral density was superimposed on the DEM, and rocks based on Moore's distribution model were added. To assess performance, selected concepts were modeled using DADS, and simulations were run with the vehicle traversing the Martian surface model, including one-meter-high vertical steps and one-meter-wide crevasses. The design details of three promising candidate systems are presented, along with the discussion of their evolution with some recommendations.

  12. Innovative Airbreathing Propulsion Concepts for Access to Space

    NASA Technical Reports Server (NTRS)

    Whitlow, Jr., Woodrow; Blech, Richard A.; Blankson, Isaiah M.

    2001-01-01

    This paper will present technologies and concepts for novel aeropropulsion systems. These technologies will enhance the safety of operations, reduce life cycle costs, and contribute to reduced costs of air travel and access to space. One of the goals of the NASA program is to reduce the carbon-dioxide emissions of aircraft engines. Engine concepts that use highly efficient fuel cell/electric drive technologies in hydrogen-fueled engines will be presented in the proposed paper. Carbon-dioxide emissions will be eliminated by replacing hydrocarbon fuel with hydrogen, and reduce NOx emissions through better combustion process control. A revolutionary exoskeletal engine concept, in which the engine drum is rotated, will be shown. This concept has the potential to allow a propulsion system that can be used for subsonic through hypersonic flight. Dual fan concepts that have ultra-high bypass ratios, low noise, and low drag will be presented. Flow-controlled turbofans and control-configured turbofans also will be discussed. To increase efficiency, a system of microengines distributed along lifting surfaces and on the fuselage is being investigated. This concept will be presented in the paper. Small propulsion systems for affordable, safe personal transportation vehicles will be discussed. These low-oil/oilless systems use technologies that enable significant cost and weight reductions. Pulse detonation engine-based hybrid-cycle and combined-cycle propulsion systems for aviation and space access will be presented.

  13. Le Point sur la Pharmacologie des Agents Anesthesiques Chez le Brule Grave

    PubMed Central

    Siah, S.; Ababou, K.; Benziane, H.; El Jaoudi; Bensghir, M.; Bakali, H.; El Wali, A.; Ihrai, I.; Drissi, N.K.

    2008-01-01

    Summary La pharmacologie des agents anesthésiques chez le brûlé est variable et imprévisible. Dans les premières 48 h, il y a une hypovolémie avec chute du débit cardiaque et des fuites plasmatiques. Après 48 h, il y a une hypervolémie avec augmentation du débit cardiaque, hypermétabolisme et la clearance des médicaments est augmentée. Parmi les facteurs de déséquilibre, on retrouve les variations des protéines plasmatiques. Deux protéines sont importantes chez le brûlé grave : l'albumine et l'alpha 1- glycoprotéine. Leur taux varie beaucoup au cours de l'évolution de la brûlure. Les agents anesthésiques dont la liaison avec ces deux protéines est prédominante verront leur pharmacocinétique modifiée. L'anesthésiste-réanimateur du service des brûlés va maîtriser ces notions pharmacologiques pour utiliser à bon escient les agents anesthésiques. PMID:21991108

  14. Synthesis of a BSA-Le(x) glycoconjugate and recognition of Le(x) analogues by the anti-Le(x) monoclonal antibody SH1: the identification of a non-cross reactive analogue.

    PubMed

    Wang, Jo-Wen; Asnani, Ari; Auzanneau, France-Isabelle

    2010-10-15

    A Le(x) trisaccharide functionalized with a cysteamine arm was prepared and this synthesis provided additional information on the reactivity of N-acetylglucosamine O-4 acceptors when they are glycosylated with trichloroacetimidate donors activated with excess BF(3)·OEt(2). In turn, this trisaccharide was conjugated to BSA lysine side chains through a squarate-mediated coupling. This BSA-Le(x) glycoconjugate displayed 35 Le(x) haptens per BSA molecule. The relative affinity of the anti-Le(x) monoclonal antibody SH1 for the Le(x) antigen and analogues of Le(x) in which the D-glucosamine, L-fucose or D-galactose residues were replaced with D-glucose, L-rhamnose and D-glucose, respectively, was measured by competitive ELISA experiments. While all analogues were weaker inhibitors than the Le(x) antigen, only the analogue of Le(x) in which the galactose residue was replaced by a glucose unit showed no binding to the SH1 mAb. To confirm that the reduced or loss of recognition of the Le(x) analogues by the anti-Le(x) mAb SH1 did not result from different conformations adopted by the analogues when compared to the native Le(x) antigen, we assessed the conformational behavior of all trisaccharides by a combination of stochastic searches and NMR experiments. Our results showed that, indeed, the analogues adopted the same stacked conformation as that identified for the Le(x) antigen. The identification of a trisaccharide analogue that does not cross-react with Le(x) but still retains the same conformation as Le(x) constitutes the first step to the design of a safe anti-cancer vaccine based on the dimeric Le(x) tumor associated carbohydrate antigen. PMID:20843695

  15. Bimodality and the Hale cycle

    NASA Technical Reports Server (NTRS)

    Wilson, Robert M.

    1988-01-01

    Evidence is provided of a modulation of between 20 and 24 yr for the Hale cycle, and comparison of consecutive pairs of cycles strongly suggests that even-numbered cycles are preferentially paired with odd-numbered following cycles. The results indicate that cycles 22 and 23 form a new cyle pair. The sum of monthly mean sunspot numbers over consecutively paired sunspot cycles for Hale cycle 12 is found to be about 19,100 + or - 3000.

  16. Introduction: Bridging Concepts.

    PubMed

    Davids, Karel

    2015-12-01

    How can those in the history of science, history of technology, and economics communicate more with each other than they are accustomed? How can they become more globally oriented? While these three disciplines today have more convergent interests than in the past, there is still a large potential for further exchange and involvement to explore and exploit. The contributors to this Focus section discuss a number of concepts that may serve as tools to bring these three disciplines more closely together and ease their evolution in a less Eurocentric direction. These concepts include trading zones, interaction and formalization, production, and machines and self-organization. PMID:27024939

  17. Concepts, states, and systems

    NASA Astrophysics Data System (ADS)

    Wolff, Karl Erich

    2000-05-01

    Mathematical System Theory is extended to Conceptual System Theory using Formal Concept Analysis (Wille 1982). States are defined as formal concepts and `points of time' are generalized to `time granules,' interpreted as `pieces' of time needed for the realization of measurements. As a generalization of classical time systems we define conceptual time systems, their state spaces and phase spaces. Time dependent relations among the parts of a conceptual time system are introduced in `relational conceptual time systems.' Applications in psychology and industry, including `conceptual films' are mentioned.

  18. Advanced SCADA concepts

    SciTech Connect

    Sciacca, S.C. ); Block, W.R. )

    1995-01-01

    The typical utility system planner faces a wide variety of concepts and applications to consider when procuring a supervisory control and data acquisition (SCADA) system. The system's performance requirements are influenced by an arena of rapidly advancing technologies and a highly competitive business environment. Unlike other elements of the electric utility industry, these changes are not evolving specifically for the SCADA industry; they are being driven by other technology forums, with a profound impact on the SCADA system of the future. This article explores some of these concepts and suggests technology and business issues to consider when planning for the SCADA system of tomorrow.

  19. Space Tug Concept

    NASA Technical Reports Server (NTRS)

    1970-01-01

    Managed by Marshall Space Flight Center, the Space Tug was intended to be a reusable multipurpose space vehicle designed to transport payloads to different orbital inclinations. Utilizing mission-specific combinations of its three primary modules (crew, propulsion, and cargo) and a variety of supplementary kits, the Space Tug would have been capable of numerous space applications. This 1970 artist's concept illustrates a Space Tug Concept, crew module attached, in conjunction with other space vehicles. The Space Tug program was cancelled and did not become a reality.

  20. Field resonance propulsion concept

    NASA Technical Reports Server (NTRS)

    Holt, A. C.

    1979-01-01

    A propulsion concept was developed based on a proposed resonance between coherent, pulsed electromagnetic wave forms, and gravitational wave forms (or space-time metrics). Using this concept a spacecraft propulsion system potentially capable of galactic and intergalactic travel without prohibitive travel times was designed. The propulsion system utilizes recent research associated with magnetic field line merging, hydromagnetic wave effects, free-electron lasers, laser generation of megagauss fields, and special structural and containment metals. The research required to determine potential, field resonance characteristics and to evaluate various aspects of the spacecraft propulsion design is described.

  1. Revisiting the matricellular concept

    PubMed Central

    Murphy-Ullrich, Joanne E.; Sage, E. Helene

    2015-01-01

    The concept of a matricellular protein was first proposed by Paul Bornstein in the mid-1990s to account for the non-lethal phenotypes of mice with inactivated genes encoding thrombospondin-1, tenascin-C, or SPARC. It was also recognized that these extracellular matrix proteins were primarily counter or de-adhesive. This review reappraises the matricellular concept after nearly two decades of continuous investigation. The expanded matricellular family as well as the diverse and often unexpected functions, cellular location, and interacting partners/receptors of matricellular proteins are considered. Development of therapeutic strategies that target matricellular proteins are discussed in the context of pathology and regenerative medicine. PMID:25064829

  2. Un exemple de transfert de technologie dans le domaine des polymères conducteurs : le projet ``HYRA"

    NASA Astrophysics Data System (ADS)

    Parneix, J. P.; Miane, J. L.; Colin, T.; Ruffie, G.; Mege, J.

    1998-06-01

    The HYRA project is a response to the restructuration of local companies : these are purveyors of high technology military and spatial especially in the radars business. Furthermore, the development of mobile communications needs devices and materials in the millimeter range (from 20 to 100Ghz). The aim of the HYRA project is the development of materials with specific properties - particularly conducting materials - in the millimeter wave range. The results obtained on thermoplastic/conducting polymer composites are presented. Le projet HYRA répond à des préoccupations régionales liées à des restructurations industrielles : les industries régionales fournissant les marchés militaires et spatiaux disposent de techniques très performantes mais coûteuses, en particulier dans le domaine des radars. Par ailleurs le développement des communications mobiles a besoin de dispositifs et de matériaux dans tout le domaine millimétrique (de 20 à 100 Ghz). Le projet HYRA a pour but le développement de matériaux à propriétés spécifiques - en particulier conducteurs - dans ce domaine de fréquence. Les résultats obtenus sur des composites thermoplastiques/polymères conducteurs sont présentés.

  3. Applied physiology of cycling.

    PubMed

    Faria, I E

    1984-01-01

    Historically, the bicycle has evolved through the stages of a machine for efficient human transportation, a toy for children, a finely-tuned racing machine, and a tool for physical fitness development, maintenance and testing. Recently, major strides have been made in the aerodynamic design of the bicycle. These innovations have resulted in new land speed records for human powered machines. Performance in cycling is affected by a variety of factors, including aerobic and anaerobic capacity, muscular strength and endurance, and body composition. Bicycle races range from a 200m sprint to approximately 5000km. This vast range of competitive racing requires special attention to the principle of specificity of training. The physiological demands of cycling have been examined through the use of bicycle ergometers, rollers, cycling trainers, treadmill cycling, high speed photography, computer graphics, strain gauges, electromyography, wind tunnels, muscle biopsy, and body composition analysis. These techniques have been useful in providing definitive data for the development of a work/performance profile of the cyclist. Research evidence strongly suggests that when measuring the cyclist's aerobic or anaerobic capacity, a cycling protocol employing a high pedalling rpm should be used. The research bicycle should be modified to resemble a racing bicycle and the cyclist should wear cycling shoes. Prolonged cycling requires special nutritional considerations. Ingestion of carbohydrates, in solid form and carefully timed, influences performance. Caffeine appears to enhance lipid metabolism. Injuries, particularly knee problems which are prevalent among cyclists, may be avoided through the use of proper gearing and orthotics. Air pollution has been shown to impair physical performance. When pollution levels are high, training should be altered or curtailed. Effective training programmes simulate competitive conditions. Short and long interval training, blended with long

  4. Innatism, Concept Formation, Concept Mastery and Formal Education

    ERIC Educational Resources Information Center

    Winch, Christopher

    2015-01-01

    This article will consider the claim that the possession of concepts is innate rather than learned. Innatism about concept learning is explained through consideration of the work of Fodor and Chomsky. First, an account of concept formation is developed. Second the argument against the claim that concepts are learned through the construction of a…

  5. Transitions de phase dans le oxyde de yttrium vanadium

    NASA Astrophysics Data System (ADS)

    Roberge, Benoit

    Dans le mémoire qui suit, les ordres structural, magnétiques et orbital dans le YVO3 sont étudiés avec l'aide de la diffraction des rayons X,de la spectroscopie Raman et de la technique de la cavité résonnante hyperfréquence. L'objectif premier consiste à observer l'évolution de ces ordres en fonction de la température. Le mémoire met ensuite en évidence le couplage entre les différents ordres cohabitants dans le YVO3 . Les mesures effectuées par la diffraction des rayons X permettent de mesurer le caractère polycrystallin des échantillons du YVO 3. Une comparaison de nos mesures avec des mesures de diffraction des rayons X faites sur la poudre de YVO3 indique la faible présence de maclage. Les mesures effectuées avec la technique de résonnance hyperfréquence permettent de suivre l'évolution de la constante diélectrique en fonction de la température. Les changements impliquant l'ordre orbital se manifestent de manière évidente dans la constante diélectrique à 200 K et à 77 K. La transition diélectrique détectée à 77 K est une transition de premier ordre. Un couplage entre les propriétés diélectriques et magnétiques est observable à la température de Néel à 114 K. L'effet d'un champ magnétique fixe sur la température de transition de l'ordre orbital survenant à 77 K est également remarquable. Cela indique un couplage magnétodiélectrique démontrant ainsi le caractère multiferroïque du YVO 3. Finalement, l'observation d'un mécanisme de relaxation pouvant être modélisé par le modèle d'Havriliak-Negami est observé en dessous de 77 K. En utilisant le modèle d'Arrhénius et le modèle d'Havriliak-Negami, on peut caractériser le mécanisme avec son énergie d'activation et son temps de relaxation. Les mesures effectuées en spectroscopie Raman permettent de suivre l'évolution de la structure du YVO3 en fonction de la température. Les deux changements structuraux survenant à 200 K et 77 K sont observés. Le

  6. Advanced Civilian Aeronautical Concepts

    NASA Technical Reports Server (NTRS)

    Bushnell, Dennis M.

    1996-01-01

    Paper discusses alternatives to currently deployed systems which could provide revolutionary improvements in metrics applicable to civilian aeronautics. Specific missions addressed include subsonic transports, supersonic transports and personal aircraft. These alternative systems and concepts are enabled by recent and envisaged advancements in electronics, communications, computing and Designer Fluid Mechanics in conjunction with a design approach employing extensive synergistic interactions between propulsion, aerodynamics and structures.

  7. Photoelectrochemistry: Introductory Concepts.

    ERIC Educational Resources Information Center

    Finklea, Harry O.

    1983-01-01

    Photoelectrochemistry is based on the semiconductor electrode. It is the semiconductor's ability to absorb light and convert it to electrical and/or chemical energy that forms the basis for the semiconductor liquid-junction solar cell. To understand how this occurs, solid-state physics concepts are discussed. (Author/JN)

  8. Some Core Contested Concepts

    ERIC Educational Resources Information Center

    Chomsky, Noam

    2015-01-01

    Core concepts of language are highly contested. In some cases this is legitimate: real empirical and conceptual issues arise. In other cases, it seems that controversies are based on misunderstanding. A number of crucial cases are reviewed, and an approach to language is outlined that appears to have strong conceptual and empirical motivation, and…

  9. DSMS science operations concept

    NASA Technical Reports Server (NTRS)

    Connally, M. J.; Kuiper, T. B.

    2001-01-01

    The Deep Space Mission System (DSMS) Science Operations Concept describes the vision for enabling the use of the DSMS, particularly the Deep Space Network (DSN) for direct science observations in the areas of radio astronomy, planetary radar, radio science and VLBI.

  10. Nursing Concepts. Teacher Edition.

    ERIC Educational Resources Information Center

    Oklahoma State Dept. of Vocational and Technical Education, Stillwater. Curriculum and Instructional Materials Center.

    This curriculum guide contains the materials required to teach a course to prepare students for employment as practical nurses. The following topics are covered in seven instructional units: successful learning skills, positive self-concept, techniques for a balanced lifestyle, communication skills, legal and ethical issues, organizational and…

  11. Infants' Concept of Animacy.

    ERIC Educational Resources Information Center

    Poulin-Dubois, Diane; And Others

    1996-01-01

    Investigates the concept of animacy of 9- and 12-month-old infants by exposing them to autonomous motion with animate and inanimate objects in a series of three experiments. Three experiments were carried out. Results indicated that infants discriminate animate from inanimate objects on the basis of motion cues by the age of nine months. (MOK)

  12. Opportunities Center. Concept Paper.

    ERIC Educational Resources Information Center

    Kimeldorf, Martin

    The opportunities center is a new school service concept that can help students find opportunities related to their talents and interests in work, education, leisure, small business, or community service. The opportunities center model expands the career center model into an information search center offering multiple services that link academic…

  13. Concept of Operations: Essence

    SciTech Connect

    Hutton, William J.

    2014-04-01

    This concept of operations is designed to give the reader a brief overview of the National Rural Electric Cooperative Association’s Essence project and a description of the Essence device design. The data collected by the device, how the data are used, and how the data are protected are also discussed in this document.

  14. Advanced Concept Modeling

    NASA Technical Reports Server (NTRS)

    Chaput, Armand; Johns, Zachary; Hodges, Todd; Selfridge, Justin; Bevirt, Joeben; Ahuja, Vivek

    2015-01-01

    Advanced Concepts Modeling software validation, analysis, and design. This was a National Institute of Aerospace contract with a lot of pieces. Efforts ranged from software development and validation for structures and aerodynamics, through flight control development, and aeropropulsive analysis, to UAV piloting services.

  15. Two Conceptions of Virtue

    ERIC Educational Resources Information Center

    Hill, Thomas E., Jr.

    2013-01-01

    The general questions are: what is virtue and how can it be cultivated? The specific focus is on the conceptions of virtue in the works of Immanuel Kant and John Rawls. Kant regarded virtue as a good will that is also strong enough to resist contrary passions, impulses, and inclinations. Childhood training can prepare children for virtue, but…

  16. Solar Thermal Propulsion Concept

    NASA Technical Reports Server (NTRS)

    2004-01-01

    Harnessing the Sun's energy through Solar Thermal Propulsion will propel vehicles through space by significantly reducing weight, complexity, and cost while boosting performance over current conventional upper stages. Another solar powered system, solar electric propulsion, demonstrates ion propulsion is suitable for long duration missions. Pictured is an artist's concept of space flight using solar thermal propulsion.

  17. Uglification: Understanding Multiplication Concepts.

    ERIC Educational Resources Information Center

    Dorwaldt, Louis E., Jr.

    1989-01-01

    Established methods of teaching multiplication (tables, flash cards, repetitive exercises) do not work well with adult underachievers. The properties and concepts of multiplication of whole numbers must be presented as observable, fun, and practical. Finger math methods may succeed where pencil and paper fail. (SK)

  18. Embodying Policy Concepts

    ERIC Educational Resources Information Center

    Evans, John; Davies, Brian

    2012-01-01

    This article introduces some of the key concepts that we have used in our research to help illuminate the multiple and different ways in which apparently ubiquitous health policies relating to obesity, exercise, diet and health are mediated and shaped both globally and nationally, as well as within regional, school and other contexts. The analyses…

  19. Force Concept Inventory.

    ERIC Educational Resources Information Center

    Hestenes, David; And Others

    1992-01-01

    Reports the rationale, design, validation, and uses of the "Force Concept Inventory," an instrument to assess the students' beliefs on force. Includes results and implications of two studies that compared the inventory with the "Mechanics Baseline." Includes a copy of the instrument. (MDH)

  20. Concepts in Environmental Education.

    ERIC Educational Resources Information Center

    Hopkins, Sally

    Presented is a discussion of the components and concepts of an ecology typical of the coastal southeastern United States. Principles presented are applicable to other areas. The discussion includes several major sections: the environment, wildlife management, freshwater ecosystems, and the estuarine environment. Numerous figures and illustrations…

  1. Mapping Sociological Concepts.

    ERIC Educational Resources Information Center

    Trepagnier, Barbara

    2002-01-01

    Focuses on the use of cognitive mapping within sociology. Describes an assignment where students created a cognitive map that focused on names of theorists and concepts related to them. Discusses sociological imagination in relation to cognitive mapping and the assessment of the assignment. (CMK)

  2. Climatic Concepts and Regions.

    ERIC Educational Resources Information Center

    Thomas, Paul F.

    Designed for students in grades 7 through 12, this teaching unit presents illustrative resource materials depicting concepts related to climate and geographic regions. Emphasis is on giving students an understanding of climatic elements and factors, not as isolated, disjointed entities, but as a dynamic interplay of forces having a very definite…

  3. Using Concept Cartoons

    ERIC Educational Resources Information Center

    Dabell, John

    2008-01-01

    Concept cartoons are cognitive drawings or "visual disagreements" that use a cartoon-style design to present mathematical conversations inside speech bubbles. The viewpoints portrayed are all different and it is this difference that acts as a catalyst for further conversations, as learners talk together to discuss their thinking. They make…

  4. Teaching Weather Concepts.

    ERIC Educational Resources Information Center

    Sebastian, Glenn R.

    Ten exercises based on the weather map provided in the national newspaper "U.S.A. Today" are used to teach intermediate grade students about weather. An overview describes the history of "U.S.A. Today," the format of the newspaper's weather map, and the map's suitability for teaching weather concepts. Specific exercises, which are briefly…

  5. Elaborating on Threshold Concepts

    ERIC Educational Resources Information Center

    Rountree, Janet; Robins, Anthony; Rountree, Nathan

    2013-01-01

    We propose an expanded definition of Threshold Concepts (TCs) that requires the successful acquisition and internalisation not only of knowledge, but also its practical elaboration in the domains of applied strategies and mental models. This richer definition allows us to clarify the relationship between TCs and Fundamental Ideas, and to account…

  6. What Is a Concept?

    ERIC Educational Resources Information Center

    Spitzer, Dean R.

    1975-01-01

    Article explores some of the key notions of the construct "concept" from the psychological and educational literature in order to demonstrate the need for standardization of definition and a more unified front in future investigations involving this important element in the study of cognition. (Author)

  7. The Concept of "Teachability."

    ERIC Educational Resources Information Center

    Tubbs, Nigel

    2003-01-01

    Asserts that "teachability" is a speculative concept that has for its form and content the absolute, suggesting that its dialectical movement and speculative significance are mis-recognized when the illusionary nature of its constitutive moments is suppressed. The essay outlines the speculative nature of the master/slave relationship in Hegel's…

  8. Learning Statistical Concepts

    ERIC Educational Resources Information Center

    Akram, Muhammad; Siddiqui, Asim Jamal; Yasmeen, Farah

    2004-01-01

    In order to learn the concept of statistical techniques one needs to run real experiments that generate reliable data. In practice, the data from some well-defined process or system is very costly and time consuming. It is difficult to run real experiments during the teaching period in the university. To overcome these difficulties, statisticians…

  9. Concept-Based Learning

    ERIC Educational Resources Information Center

    Schill, Bethany; Howell, Linda

    2011-01-01

    A major part of developing concept-based instruction is the use of an overarching idea to provide a conceptual lens through which students view the content of a particular subject. By using a conceptual lens to focus learning, students think at a much deeper level about the content and its facts (Erickson 2007). Therefore, the authors collaborated…

  10. Teaching Aerobic Fitness Concepts.

    ERIC Educational Resources Information Center

    Sander, Allan N.; Ratliffe, Tom

    2002-01-01

    Discusses how to teach aerobic fitness concepts to elementary students. Some of the K-2 activities include location, size, and purpose of the heart and lungs; the exercise pulse; respiration rate; and activities to measure aerobic endurance. Some of the 3-6 activities include: definition of aerobic endurance; heart disease risk factors;…

  11. The Rock Cycle

    ERIC Educational Resources Information Center

    Singh, Raman J.; Bushee, Jonathan

    1977-01-01

    Presents a rock cycle diagram suitable for use at the secondary or introductory college levels which separates rocks formed on and below the surface, includes organic materials, and separates products from processes. (SL)

  12. Mining the Learning Cycle.

    ERIC Educational Resources Information Center

    Hemler, Debra; King, Hobart

    1996-01-01

    Describes an approach that uses the learning cycle to meaningfully teach students about mineral properties while alleviating the tedious nature of identifying mineral specimens. Discusses mineral properties, cooperative learning, and mineral identification. (JRH)

  13. Life Cycle Costing.

    ERIC Educational Resources Information Center

    McCraley, Thomas L.

    1985-01-01

    Life cycle costing establishes a realistic comparison of the cost of owning and operating products. The formula of initial cost plus maintenance plus operation divided by useful life identifies the best price over the lifetime of the product purchased. (MLF)

  14. The global carbon cycle

    SciTech Connect

    Sedjo, R.A. )

    1990-10-01

    The author discusses the global carbon cycle and cites the results of several recently completed research projects, that seem to indicate that the temperate zone forests are a sink for carbon rather than a source, as was previously believed.

  15. Solar Cycle Prediction

    NASA Technical Reports Server (NTRS)

    Pesnell, William Dean

    2011-01-01

    Solar cycle predictions are needed to plan long-term space missions; just like weather predictions are needed to plan your next vacation. Fleets of satellites circle the Earth collecting many types of science data, protecting astronauts, and relaying information. All of these satellites are sensitive at some level to solar cycle effects. Predictions of drag on LEO spacecraft are one of the most important. Launching a satellite with less propellant can mean a higher orbit, but unanticipated solar activity and increased drag can make that a Pyrrhic victory. Energetic events at the Sun can produce crippling radiation storms that endanger all assets in space. Testing solar dynamo theories by quantitative predictions of what will happen in 5-20 years is the next arena for solar cycle predictions. I will describe the current state of solar cycle predictions and anticipate how those predictions could be made more accurate in the future.

  16. Cycle isolation monitoring

    SciTech Connect

    Svensen, L.M. III; Zeigler, J.R.; Todd, F.D.; Alder, G.C.

    2009-07-15

    There are many factors to monitor in power plants, but one that is frequently overlooked is cycle isolation. Often this is an area where plant personnel can find 'low hanging fruit' with great return on investment, especially high energy valve leakage. This type of leakage leads to increased heat rate, potential valve damage and lost generation. The fundamental question to ask is 'What is 100 Btu/kW-hr of heat rate worth to your plant? On a 600 MW coal-fired power plant, a 1% leakage can lead to an 81 Btu/kW-hr impact on the main steam cycle and a 64 Btu/kW-hr impact on the hot reheat cycle. The article gives advice on methods to assist in detecting leaking valves and to monitor cycle isolation. A software product, TP. Plus-CIM was designed to estimate flow rates of potentially leaking valves.

  17. Observing the Global Water Cycle from Space

    NASA Technical Reports Server (NTRS)

    Hildebrand, Peter H.; Houser, Paul; Schlosser, C. Adam

    2003-01-01

    This paper presents an approach to measuring all major components of the water cycle from space. The goal of the paper is to explore the concept of using a sensor-web of satellites to observe the global water cycle. The details of the required measurements and observation systems are therefore only an initial approach and will undergo future refinement, as their details will be highly important. Key elements include observation and evaluation of all components of the water cycle in terms of the storage of water-in the ocean, air, cloud and precipitation, in soil, ground water, snow and ice, and in lakes and rivers-and in terms of the global fluxes of water between these reservoirs. For each component of the water cycle that must be observed, the appropriate temporal and spatial scales of measurement are estimated, along with the some of the frequencies that have been used for active and passive microwave observations of the quantities. The suggested types of microwave observations are based on the heritage for such measurements, and some aspects of the recent heritage of these measurement algorithms are listed. The observational requirements are based on present observational systems, as modified by expectations for future needs. Approaches to the development of space systems for measuring the global water cycle can be based on these observational requirements.

  18. Rocketdyne RBCC Engine Concept Development

    NASA Technical Reports Server (NTRS)

    Ratckin, G.; Goldman, A.; Ortwerth, P.; Weisberg, S.

    1999-01-01

    Boeing Rocketdyne is pursuing the development of Rocket Based Combined Cycle (RBCC), propulsion systems as demonstrated by significant contract work in the hypersonic arena (ART, NASP, SCT, system studies) and over 12 years of steady company discretionary investment. The Rocketdyne concept is a fixed geometry integrated rocket, ramjet, scramjet which is hydrogen fueled and uses hydrogen regenerative cooling. The baseline engine structural configuration uses an integral structure that eliminates panel seals. seal purge gas, and closeout side attachments. Rocketdyne's experimental RBCC engine (Engine A5) was constructed under contract with the NASA Marshall Space Flight Center. Engine A5 models the complete flight engine flowpath consisting of an inlet, isolator, airbreathing combustor and nozzle. High performance rocket thrusters are integrated into the engine to enable both air-augmented rocket (AAR) and pure rocket operation. Engine A5 was tested in CASL's new FAST facility as an air-augmented rocket, a ramjet and a pure rocket. Measured performance demonstrated vision vehicle performance levels for Mach 3 AAR operation and ramjet operation from Mach 3 to 4. Rocket mode performance was above predictions. For the first time. testing also demonstrated transition from AAR operation to ramjet operation. This baseline configuration has also been shown, in previous testing, to perform well in the scramjet mode.

  19. LIFE CYCLE ENGINEERING GUIDELINES

    EPA Science Inventory

    This document provides guidelines for the implementation of LCE concepts, information, and techniques in engineering products, systems, processes, and facilities. To make this document as practical and useable as possible, a unifying LCE framework is presented. Subsequent topics ...

  20. Solar Cycle Predictions

    NASA Technical Reports Server (NTRS)

    Pesnell, William Dean

    2012-01-01

    Solar cycle predictions are needed to plan long-term space missions; just like weather predictions are needed to plan the launch. Fleets of satellites circle the Earth collecting many types of science data, protecting astronauts, and relaying information. All of these satellites are sensitive at some level to solar cycle effects. Predictions of drag on LEO spacecraft are one of the most important. Launching a satellite with less propellant can mean a higher orbit, but unanticipated solar activity and increased drag can make that a Pyrrhic victory as you consume the reduced propellant load more rapidly. Energetic events at the Sun can produce crippling radiation storms that endanger all assets in space. Solar cycle predictions also anticipate the shortwave emissions that cause degradation of solar panels. Testing solar dynamo theories by quantitative predictions of what will happen in 5-20 years is the next arena for solar cycle predictions. A summary and analysis of 75 predictions of the amplitude of the upcoming Solar Cycle 24 is presented. The current state of solar cycle predictions and some anticipations how those predictions could be made more accurate in the future will be discussed.

  1. Malone cycle refrigerator development

    SciTech Connect

    Shimko, M.A.; Crowley, C.J.

    1999-07-01

    This paper describes the progress made in demonstrating a Malone Cycle Refrigerator/Freezer. The Malone cycle is similar to the Stirling cycle but uses a supercritical fluid in place of real gas. In the approach, solid-metal diaphragms are used to seal and sweep the working volumes against the high working fluid pressures required in Malone cycle machines. This feature eliminates the friction and leakage that accounted for nearly half the losses in the best piston-defined Malone cycle machines built to date. The authors successfully built a Malone cycle refrigerator that: (1) used CO{sub 2} as the working fluid, (2) operated at pressures up to 19.3 Mpa (2,800 psi), (3) achieved a cold end metal temperatures of {minus}29 C ({minus}20 F), and (4) produced over 400 Watts of cooling at near ambient temperatures. The critical diaphragm components operated flawlessly throughout characterization and performance testing, supporting the conclusion of high reliability based on analysis of fatigue date and actual strain measurements.

  2. Quantifying the Adaptive Cycle

    PubMed Central

    Angeler, David G.; Allen, Craig R.; Garmestani, Ahjond S.; Gunderson, Lance H.; Hjerne, Olle; Winder, Monika

    2015-01-01

    The adaptive cycle was proposed as a conceptual model to portray patterns of change in complex systems. Despite the model having potential for elucidating change across systems, it has been used mainly as a metaphor, describing system dynamics qualitatively. We use a quantitative approach for testing premises (reorganisation, conservatism, adaptation) in the adaptive cycle, using Baltic Sea phytoplankton communities as an example of such complex system dynamics. Phytoplankton organizes in recurring spring and summer blooms, a well-established paradigm in planktology and succession theory, with characteristic temporal trajectories during blooms that may be consistent with adaptive cycle phases. We used long-term (1994–2011) data and multivariate analysis of community structure to assess key components of the adaptive cycle. Specifically, we tested predictions about: reorganisation: spring and summer blooms comprise distinct community states; conservatism: community trajectories during individual adaptive cycles are conservative; and adaptation: phytoplankton species during blooms change in the long term. All predictions were supported by our analyses. Results suggest that traditional ecological paradigms such as phytoplankton successional models have potential for moving the adaptive cycle from a metaphor to a framework that can improve our understanding how complex systems organize and reorganize following collapse. Quantifying reorganization, conservatism and adaptation provides opportunities to cope with the intricacies and uncertainties associated with fast ecological change, driven by shifting system controls. Ultimately, combining traditional ecological paradigms with heuristics of complex system dynamics using quantitative approaches may help refine ecological theory and improve our understanding of the resilience of ecosystems. PMID:26716453

  3. Design study of prestressed rotor spar concept

    NASA Technical Reports Server (NTRS)

    Gleich, D.

    1980-01-01

    Studies on the Bell Helicopter 540 Rotor System of the AH-1G helicopter were performed. The stiffness, mass and geometric configurations of the Bell blade were matched to give a dynamically similar prestressed composite blade. A multi-tube, prestressed composite spar blade configuration was designed for superior ballistic survivability at low life cycle cost. The composite spar prestresses, imparted during fabrication, are chosen to maintain compression in the high strength cryogenically stretchformed 304-L stainless steel liner and tension in the overwrapped HTS graphite fibers under operating loads. This prestressing results in greatly improved crack propagation and fatigue resistance as well as enhanced fiber stiffness properties. Advantages projected for the prestressed composite rotor spar concept include increased operational life and improved ballistic survivability at low life cycle cost.

  4. Concepts in Activities and Discourses

    ERIC Educational Resources Information Center

    Greeno, James G.

    2012-01-01

    The articles in this special issue make valuable contributions toward a scientific understanding of concepts that is broader than the traditional view that has focused on categorizing by individuals. I propose considering concepts for categorization as a special case of concepts. At their clearest, they can be referred to as "formal concepts," or…

  5. Separations innovative concepts: Project summary

    SciTech Connect

    Lee, V.E.

    1988-05-01

    This project summary includes the results of 10 innovations that were funded under the US Department's Innovative Concept Programs. The concepts address innovations that can substantially reduce the energy used in industrial separations. Each paper describes the proposed concept, and discusses the concept's potential energy savings, market applications, technical feasibility, prior work and state of the art, and future development needs.

  6. Key Concepts in Informatics: Algorithm

    ERIC Educational Resources Information Center

    Szlávi, Péter; Zsakó, László

    2014-01-01

    "The system of key concepts contains the most important key concepts related to the development tasks of knowledge areas and their vertical hierarchy as well as the links of basic key concepts of different knowledge areas." (Vass 2011) One of the most important of these concepts is the algorithm. In everyday life, when learning or…

  7. Le risque de détresse morale dans la pratique contemporaine des soins de santé.

    PubMed

    Austin, Wendy

    2016-05-01

    Les professionnels de la santé sont des agents moraux dont la relation fiduciaire avec le public est animée par la responsabilité et la promesse de puiser dans leurs connaissances et leurs habiletés pour aider les personnes sous leurs soins. Lorsque leur capacité à tenir cette promesse est freinée ou compromise, ils risquent de souffrir de détresse morale. Le concept de détresse morale est défini et mis en contexte dans le milieu de la santé. Les contraintes et les facteurs qui en sont à l'origine sont présentés, de même que les moyens utilisés par les professionnels de la santé et les organisations de santé pour la soulager. Un changement transformateur s'impose pour vaincre la culture du silence et maintenir un système de santé où il est possible de vivre avec sa conscience. PMID:27068874

  8. Expression of blood group antigens H-2, Le(y), and sialylated-Le(a) in human colorectal carcinoma. An immunohistochemical study using double-labeling techniques.

    PubMed Central

    Cooper, H. S.; Malecha, M. J.; Bass, C.; Fagel, P. L.; Steplewski, Z.

    1991-01-01

    In this study, double-labeling immunohistochemistry was used to gain insight into the coexpression or interrelationship between blood group antigens (BGA) that are differentiation antigens in the normal colon, and BGA that are sequential moieties in the same synthetic pathway. Paired-wise Sialylated-Le(a)/Le(y) and H-2/Le(y) was studied. The Sialylated-Le(a) and Le(y) are synthesized from type 1 and type 2 backbones, respectively. In the normal colon, the Le(y) and Sialylated-Le(a) are expressed by cells at the base and surface of the crypt, respectively, representing undifferentiated and differentiated enterocytes. The H-2 is considered oncofetal in nature, and is considered to be the immediate precursor in the synthesis of Le(y). In individual cancers. Sialylated-Lea and Le(y) were detected in different cancer cells within the same malignant glands, separately in different glands, and in different subcellular compartments of the same cell. Both H-2 and Le(y) were coexpressed in the same individual cells in 92% of cancers expressing both these BGA. In 50% of the cancers, the H-2 and Le(y) also were expressed separately in different malignant glands within individual tumors. These findings indicate that, in colorectal cancers, differentiation antigens (Sialylated Le(a) and Le(y)) are expressed by different individual cells within the same malignant gland somewhat, recapitulating the normal colon crypt. Antigens of different backbones occasionally may be expressed in the same cells but within different subcellular compartments. Precursor accumulation is common in cancers, and antigens in the same synthetic pathway are coexpressed in the same cell. The expression of H-2 and Le(y) in different glands (lack of coexpression) may be explained possibly by aberrant synthesis of Le(y) by an alternate pathway. Images Figure 1 PMID:1987759

  9. US/CIS integrated NTRE concept

    SciTech Connect

    Bulman, M.J.; Culver, D.W.; McIlwain, M.C. ); D'yakov, E.K. ); Smetannikov, V.P. ); Rochow, R. )

    1993-01-10

    The team of Aerojet, Energopool and Babcock Wilcox has prepared a near-term Nuclear Thermal Rocket Engine (NTRE) concept that takes advantage of mature fuel technology developed in the former Soviet Union. This proven, advanced fuel appreciably shortens the development schedule of this engine for Moon and Mars exploration. Our near term engine has a number of features that provide safety, mission performance, cost and risk benefits, including: (1) High temperature, long life CIS fuel, (2) high pressure, recuperated topping cycle, (3) assured restart, (4) long life, cooled nozzle with thin inner wall, (5) long life turbopumps, (6) heat radiation and electrical power generation, and (7) component integration energy.

  10. Artist's Concept of the Orbiting Carbon Observatory

    NASA Technical Reports Server (NTRS)

    2008-01-01

    Artist's concept of the Orbiting Carbon Observatory. The mission, scheduled to launch in early 2009, will be the first spacecraft dedicated to studying atmospheric carbon dioxide, the principal human-produced driver of climate change. It will provide the first global picture of the human and natural sources of carbon dioxide and the places where this important greenhouse gas is stored. Such information will improve global carbon cycle models as well as forecasts of atmospheric carbon dioxide levels and of how our climate may change in the future.

  11. Trigeminocardiac reflex and haemodynamic changes during Le Fort I osteotomy.

    PubMed

    Kiani, M T; Tajik, G; Ajami, M; Fazli, H; Kharazifard, M J; Mesgarzadeh, A

    2016-05-01

    The Le Fort I osteotomy is performed under general anaesthesia and specific haemodynamic conditions, i.e. hypotensive general anaesthesia. This study assessed the incidence of the trigeminocardiac reflex (TCR) during the different stages of the Le Fort I osteotomy. Forty-seven patients requiring a Le Fort I osteotomy were included. General anaesthesia was induced. In terms of haemodynamic changes, each patient's oxygen saturation (SpO2), mean arterial pressure (MAP), heart rate (HR), and electrocardiogram (ECG) were monitored by SADAAT Monitoring System and recorded during the different stages of osteotomy: before the induction of anaesthesia, before osteotomy cuts, after finishing the right pterygoid plate osteotomy, after finishing the left pterygoid plate osteotomy, and after performing down-fracture of the maxilla. No significant alteration in haemodynamic values was seen at the different stages of Le Fort I osteotomy. One patient showed arrhythmia with non-sinus junction rhythm after sinus bradycardia and two premature atrial contractions in the down-fracture stage, which led to the abrupt cessation of the procedure by the surgeon. This study showed no significant alterations in haemodynamic values during the different stages of Le Fort I osteotomy. Halting the procedure momentarily was sufficient to allow spontaneous normalization of the HR, blood pressure, and dysrhythmia. PMID:26794400

  12. Freehand Sketching as a Catalyst for Developing Concept Driven Competencies

    ERIC Educational Resources Information Center

    Lane, Diarmaid; Seery, Niall

    2011-01-01

    At a time when concept driven competencies are perceived to be critical in redefining effective technological education, the introduction of Design and Communication Graphics at senior cycle in Irish high schools has broad implications. Students now have the potential to explore applied geometries, integrated with conceptual thinking in addition…

  13. Which position for MIL-space industry facing QML concept

    NASA Astrophysics Data System (ADS)

    Cuny, P.; Barre, M.

    1991-03-01

    Use of the European Quality Management system EQML by part manufacturers, equipment manufacturers and system users is discussed. Evolution of normalized qualification standards enabling better confidence and cost efficiency in new product generation is discussed. Ways of improving development cycles, yields and product performances using the EQML system are outlined. The main phases involved in the qualification concept are identified.

  14. A Field Course Teaching Research Concepts in Environmental Geochemistry.

    ERIC Educational Resources Information Center

    Brown, Foster; De Lacerda, Luiz Drude

    1986-01-01

    Describes a graduate field course taught in Brazil that uses a system concept and the geochemical cycle as unifying paradigms to study various environments. Emphasizes the acquisition of techniques of integrated observation, using operational definitions, measurement scales, and a priori hypotheses. (Author/TW)

  15. Advanced ramjet concepts program

    NASA Technical Reports Server (NTRS)

    Leingang, J. L.

    1992-01-01

    Uniquely advantageous features, on both the performance and weight sides of the ledger, can be achieved through synergistic design integration of airbreathing and rocket technologies in the development of advanced orbital space transport propulsion systems of the combined cycle type. In the context of well understood advanced airbreathing and liquid rocket propulsion principles and practices, this precept of synergism is advanced mainly through six rather specific examples. These range from the detailed component level to the overall vehicle system level as follows: using jet compression; achieving a high area ratio rocket nozzle; ameliorating gas generator cycle rocket system deficiencies; using the in-duct special rocket thrust chamber assembly as the principal scramjet fuel injection operation; using the unstowed, covered fan as a duct closure for effecting high area ratio rocket mode operation; and creating a unique airbreathing rocket system via the onboard, cryogenic hydrogen induced air liquefaction process.

  16. Free radical propulsion concept

    NASA Technical Reports Server (NTRS)

    Hawkins, C. E.; Nakanishi, S.

    1981-01-01

    A free radical propulsion concept utilizing the recombination energy of dissociated low molecular weight gases to produce thrust was examined. The concept offered promise of a propulsion system operating at a theoretical impulse, with hydrogen, as high as 2200 seconds at high thrust to power ratio, thus filling the gas existing between chemical and electrostatic propulsion capabilities. Microwave energy used to dissociate a continuously flowing gas was transferred to the propellant via three body recombination for conversion to propellant kinetic energy. Power absorption by the microwave plasma discharge was in excess of 90 percent over a broad range of pressures. Gas temperatures inferred from gas dynamic equations showed much higher temperatures from microwave heating than from electrothermal heating. Spectroscopic analysis appeared to corroborate the inferred temperatures of one of the gases tested.

  17. Advanced sulfur control concepts

    SciTech Connect

    Harrison, D.P.; Lopez-Ortiz, A.; White, J.D.; Groves, F.R. Jr.

    1995-11-01

    The primary objective of this study is the direct production of elemental sulfur during the regeneration of high temperature desulfurization sorbents. Three possible regeneration concepts were identified as a result of a literature search. The potential for elemental sulfur production from a number of candidate metal oxide sorbents using each regeneration concept was evaluated on the basis of a thermodynamic analysis. Two candidate sorbents, Fe{sub 2}O{sub 3} and CeO{sub 2} were chosen for experimental testing. The experimental test program using both electrobalance and fixed-bed reactor sis now getting underway. The objective is to determine reaction conditions--temperature, pressure, space velocity, and regeneration feed gas composition--which will maximize the yield of elemental sulfur in the regeneration product gas. Experimental results are to be used to define a conceptual desulfurization-regeneration process and to provide a preliminary economic evaluation.

  18. [Loneliness: a concept analysis].

    PubMed

    Huang, Yi-Jen; Wang, Kwua-Yun; Chen, Chin-Mi

    2010-10-01

    Loneliness is a kind of mood that most people have experienced at one time or another. Individual experiences with loneliness as joyful or painful saturation are highly personal and can be defined only in such a context. Loneliness has differing effects on the long-term health of individuals. Although loneliness impacts greatly on individual health, there is little in the literature related to concept analyses of loneliness. The purpose of this article was to use Walker and Avant's (2005) concept analysis methodology to review conceptual definitions of loneliness, characteristics, antecedents and consequences; construct examples and establish empirical measurements. Results indicate that defining attributes of loneliness included an individual's subjective mood, descriptions of aloneness, depression, desolation or empty feelings, and the perception of the spirit isolated from others. It is hoped that nursing staffs may better understand loneliness through this article, provide an assessment of client loneliness as early as possible, and enhance client health condition. PMID:20878616

  19. Modified Purex first-cycle extraction for neptunium recovery

    SciTech Connect

    Dinh, Binh; Moisy, Philippe; Baron, Pascal; Calor, Jean-Noel; Espinoux, Denis; Lorrain, Brigitte; Benchikouhne-Ranchoux, Magali

    2008-07-01

    A new PUREX first-cycle flowsheet was devised to enhance the extraction yield of neptunium at the extraction step of this cycle. Simulation results (using a qualified process-simulation tool), le d to raising the nitric acid concentration of the feed from 3 M to 4.5 M to allow extraction of more than 99% of the neptunium. This flowsheet was operated in the shielded process cell of ATALANTE facility using pulsed columns and mixer-settlers banks. A 15 kg quantity of genuine oxide fuel of average burn up of 52 GWd/t with cooling time of nearly five years was treated, and the neptunium extraction yield obtained was greater than 99.6%. (authors)

  20. The 11-year cycle in human births

    NASA Astrophysics Data System (ADS)

    Randall, Walter; Moos, Walter S.

    1993-06-01

    The annual numbers of human births were analyzed with regard to an 11-year cycle. The annual values were obtained from seven different regions: Australia, Germany, England and Wales, New Zealand, Japan, Switzerland, and the USA. Fifty-five annual values were obtained from each region for the years 1930 to 1984, comprising approximately five sunspot cycles. For each region the annual values were formed into 5 by 11 matrices; the eleven column means obtained were standardized, and plotted. A periodic regression technique, utilizing the fitting functions of the Fourier series, was used to evaluate the temporal order in the column means. Eleven-year rhythms were found and compared with solar and geophysical variables. Correlations were found with sunspots and solar flares, with terrestrial measures of magnetic disturbances (the magnetic indices derived from the K-index), and with temperature. The correlation of conceptions with the 11-year solar cycle may be a potential guide in the selection of further variables for the control and regulation of the rhythms in human conceptions.

  1. Firefly system concept

    NASA Technical Reports Server (NTRS)

    Nichols, J. D.

    1991-01-01

    The 'Firefly' project has developed and implemented an infrared (IR) remote sensing prototype system based on the concept presented. The Firefly system produces images through smoke that will provide near real-time wildland fire information for fire management and suppression. The prototype will be tested through the 1991 fire season. Results of the testing will be incorporated into the final system design for operational use at the end of 1992.

  2. Advanced space propulsion concepts

    NASA Technical Reports Server (NTRS)

    Lapointe, Michael R.

    1993-01-01

    The NASA Lewis Research Center has been actively involved in the evaluation and development of advanced spacecraft propulsion. Recent program elements have included high energy density propellants, electrode less plasma thruster concepts, and low power laser propulsion technology. A robust advanced technology program is necessary to develop new, cost-effective methods of spacecraft propulsion, and to continue to push the boundaries of human knowledge and technology.

  3. Firefly system concept

    NASA Astrophysics Data System (ADS)

    Nichols, Joseph D.

    1991-12-01

    The Firefly project has developed and implemented an infrared (IR) remote sensing prototype system based on the concept presented. The Firefly system produces image through smoke that will provide near real-time wildland fire information for fire management and suppression. The prototype will be tested through the 1991 fire season. Results of the testing will be incorporated into the final system design for operational use at the end of 1992.

  4. Elaborating on threshold concepts

    NASA Astrophysics Data System (ADS)

    Rountree, Janet; Robins, Anthony; Rountree, Nathan

    2013-09-01

    We propose an expanded definition of Threshold Concepts (TCs) that requires the successful acquisition and internalisation not only of knowledge, but also its practical elaboration in the domains of applied strategies and mental models. This richer definition allows us to clarify the relationship between TCs and Fundamental Ideas, and to account for both the important and the problematic characteristics of TCs in terms of the Knowledge/Strategies/Mental Models Framework defined in previous work.

  5. Le lipome para testiculaire: à propos d'un cas rare

    PubMed Central

    Lasri, Abdelouahed; Lamchahab, Hamza; Lahyani, Mounir; Karmouni, Tarik; Elkhader, Khalid; Koutani, Abdellatif; Andaloussi, Ahmed Ibn Attya

    2015-01-01

    Les tumeurs para testiculaires sont des tumeurs rares et complexes qui ont une symptomatologie insidieuse et pauvre. Les formes bénignes représentent 70%. Le lipome para testiculaire étant le type le plus fréquent. L'examen clinique est peu spécifique. L'examen échographique est la pierre angulaire pour assoir le diagnostic. Le traitement chirurgical s'impose en cas de tumeur symptomatique, l'histologie étant habituellement typique permet la confirmation diagnostique. Le pronostic est bon malgré d’éventuelles récidives. PMID:26175802

  6. The concept of compartmentalisation.

    PubMed

    Scott, A; Zepeda, C; Garber, L; Smith, J; Swayne, D; Rhorer, A; Kellar, J; Shimshony, A; Batho, H; Caporale, V; Giovannini, A

    2006-12-01

    The rationale for establishing trade 'regions' and 'zones' is based on principles of epidemiological science and risk analysis that assess and manage animal disease risks so that the safety of trade can be ensured. However, the boundaries of geographical regions and zones may readily be breached through numerous epidemiological pathways. The concept of a 'compartment' extends the application of a 'risk boundary' beyond that of a geographical interface and considers all epidemiological factors that can contribute to the creation of an effective boundary. The fundamental requirement for application of either concept (regions/zones or compartments) is that the population considered for trade is maintained within management or geographical boundaries which allow clear epidemiological differentiation to be made between those animals and surrounding populations of higher risk. Seven factors are presented that an exporting country might use to guide the identification and documentation of a compartment. Additionally, the steps that would be undertaken to implement trade based on the compartmentalisation concept are discussed. PMID:17361758

  7. [Insomnia: concept analysis].

    PubMed

    Sun, Jia-Ling; Lin, Chia-Clin; Tsai, Pei-Shan; Chou, Kuei-Ru

    2008-10-01

    Sleep performs an essential function in humans. Insomnia is one of the common phenomena in a poor sleep pattern. Long-term suffering can result in somatic symptoms and the development of diseases. It can even induce diseases with a mental dimension. Insomnia causes indications of poor health. No systematic analysis of insomnia has been performed, however. The purpose of this study, therefore, was to describe the concept of insomnia. In accordance with Walker and Avant's (2005) methodology of concept analysis, this paper presents a review of the conceptual definitions, characteristics, antecedents and consequences, constructing examples, and empirical references of insomnia. The results indicate that: (1) Insomnia's defining attributes are recognized as an insufficient of quality and quantity for sleep for more than one month. (2) Antecedents of insomnia include changes in life habits, physiological demands caused by sleep time changes, and the experience of uncomfortable sensations. (3) Consequences of insomnia include a poor condition, with physical, psychological, social, and global dimensions. (4) There are many instruments that can be used to inspect insomnia, including questionnaires and tools for physiological measurement. Insomnia is a serious problem with various facets. An understanding of the concept of insomnia will help nurses to perceive this problem in caring for subjects. PMID:18836979

  8. Hermes thermal control concept

    NASA Astrophysics Data System (ADS)

    Moscatelli, Antonio; Bottaccini, Massimiliano; Ferro, Claudio

    1991-12-01

    The Hermes Space Vehicle is made up of the reusable Hermes Spaceplane (HSP) itself and an expendable rear Hermes Resource Module (HRM). Both the HSP and HRM contain pressurized (habitable) compartments and unpressurized compartments. The complex configuration of the space vehicle and the mission profile require the adoption of a particularly flexible thermal control system which can satisfy the different requirements of the HSP and the HRM together with stringent safety and reliability requirements. All these aspects led to a thermal control design concept which uses active and passive means distributed through all compartments of the space vehicle. The ACTS (Active Thermal Control Section) is dedicated to the control of very high and concentrated thermal loads. It is based on a dual loop concept for heat collection (water and Freon R114 cooling loops), transportation and rejection through dedicated devicers. The PTCS (Passive Thermal Control Section) controls low heat fluxes spread on large surfaces. It relies on different concepts of insulation together with a system of temperature sensors and heaters, to control the thermal excursions of the space plane components and internal structural parts.

  9. Helium process cycle

    DOEpatents

    Ganni, Venkatarao

    2008-08-12

    A unique process cycle and apparatus design separates the consumer (cryogenic) load return flow from most of the recycle return flow of a refrigerator and/or liquefier process cycle. The refrigerator and/or liquefier process recycle return flow is recompressed by a multi-stage compressor set and the consumer load return flow is recompressed by an independent consumer load compressor set that maintains a desirable constant suction pressure using a consumer load bypass control valve and the consumer load return pressure control valve that controls the consumer load compressor's suction pressure. The discharge pressure of this consumer load compressor is thereby allowed to float at the intermediate pressure in between the first and second stage recycle compressor sets. Utilizing the unique gas management valve regulation, the unique process cycle and apparatus design in which the consumer load return flow is separate from the recycle return flow, the pressure ratios of each recycle compressor stage and all main pressures associated with the recycle return flow are allowed to vary naturally, thus providing a naturally regulated and balanced floating pressure process cycle that maintains optimal efficiency at design and off-design process cycle capacity and conditions automatically.

  10. Helium process cycle

    DOEpatents

    Ganni, Venkatarao

    2007-10-09

    A unique process cycle and apparatus design separates the consumer (cryogenic) load return flow from most of the recycle return flow of a refrigerator and/or liquefier process cycle. The refrigerator and/or liquefier process recycle return flow is recompressed by a multi-stage compressor set and the consumer load return flow is recompressed by an independent consumer load compressor set that maintains a desirable constant suction pressure using a consumer load bypass control valve and the consumer load return pressure control valve that controls the consumer load compressor's suction pressure. The discharge pressure of this consumer load compressor is thereby allowed to float at the intermediate pressure in between the first and second stage recycle compressor sets. Utilizing the unique gas management valve regulation, the unique process cycle and apparatus design in which the consumer load return flow is separate from the recycle return flow, the pressure ratios of each recycle compressor stage and all main pressures associated with the recycle return flow are allowed to vary naturally, thus providing a naturally regulated and balanced floating pressure process cycle that maintains optimal efficiency at design and off-design process cycle capacity and conditions automatically.

  11. Pterygoid Plate Fractures: Not Limited to Le Fort Fractures.

    PubMed

    Garg, Ravi K; Alsheik, Nila H; Afifi, Ahmed M; Gentry, Lindell R

    2015-09-01

    Pterygoid plate fractures are often described in the setting of Le Fort fractures. The goal of this study was to define other craniofacial fracture patterns causing injury to the pterygoid plates. A retrospective review of computed tomography (CT) scans obtained on craniofacial trauma patients over a 5-year period revealed 209 patients with pterygoid plate fractures. Pterygoid plate fractures in 78 patients (37.3%) were unrelated to Le Fort fractures. Common causes included sphenotemporal buttress fractures in 26 patients (33.3%), temporal bone fractures in 18 patients (23.1%), zygomaticomaxillary complex fractures in 17 patients (21.8%), and displaced mandible fractures in 14 patients (17.9%). These findings indicate that approximately one third of pterygoid plate fractures do not result from Le Fort pattern injuries and that the craniofacial surgeon should have a broad differential for causes of pterygoid plate fractures when reviewing trauma imaging. PMID:26147022

  12. Le zona ophtalmique: une dermatose rare chez l'enfant

    PubMed Central

    Zakia, Douhi; Meziane, Marieme; Salim, Gallouj; Zahra, Mernissi Fatima

    2015-01-01

    Le zona est dû a une réactivation du virus varicelle-zona (VZV) qui reste quiescent dans les ganglions sensitifs dorsaux après la varicelle. Le zona de l'enfant est rare et particulièrement la forme ophtalmique, qui peut être responsable de complications oculaires graves nécessitant une prise en charge adéquate et précoce. Il est parfois associé à des douleurs post-zostériennes dont le traitement est difficile. L'aciclovir per os administré dans les 72 heures après l’éruption a prouvé son efficacité dans la prévention des complications oculaires. Nous en rapportant un nouveaux cas chez un garçon immunocompétent de 9 ans, sans notion de varicelle antérieure. PMID:26955408

  13. Methodologie de conception numerique d'un ventilateur helico-centrifuge basee sur l'emploi du calcul meridien

    NASA Astrophysics Data System (ADS)

    Lallier-Daniels, Dominic

    La conception de ventilateurs est souvent basée sur une méthodologie « essais/erreurs » d'amélioration de géométries existantes ainsi que sur l'expérience de design et les résultats expérimentaux cumulés par les entreprises. Cependant, cette méthodologie peut se révéler coûteuse en cas d'échec; même en cas de succès, des améliorations significatives en performance sont souvent difficiles, voire impossibles à obtenir. Le projet présent propose le développement et la validation d'une méthodologie de conception basée sur l'emploi du calcul méridien pour la conception préliminaire de turbomachines hélico-centrifuges (ou flux-mixte) et l'utilisation du calcul numérique d'écoulement fluides (CFD) pour la conception détaillée. La méthode de calcul méridien à la base du processus de conception proposé est d'abord présentée. Dans un premier temps, le cadre théorique est développé. Le calcul méridien demeurant fondamentalement un processus itératif, le processus de calcul est également présenté, incluant les méthodes numériques de calcul employée pour la résolution des équations fondamentales. Une validation du code méridien écrit dans le cadre du projet de maîtrise face à un algorithme de calcul méridien développé par l'auteur de la méthode ainsi qu'à des résultats de simulation numérique sur un code commercial est également réalisée. La méthodologie de conception de turbomachines développée dans le cadre de l'étude est ensuite présentée sous la forme d'une étude de cas pour un ventilateur hélico-centrifuge basé sur des spécifications fournies par le partenaire industriel Venmar. La méthodologie se divise en trois étapes: le calcul méridien est employé pour le pré-dimensionnement, suivi de simulations 2D de grilles d'aubes pour la conception détaillée des pales et finalement d'une analyse numérique 3D pour la validation et l'optimisation fine de la géométrie. Les résultats de calcul m

  14. Solar dynamic heat rejection technology. Task 1: System concept development

    NASA Technical Reports Server (NTRS)

    Gustafson, Eric; Carlson, Albert W.

    1987-01-01

    The results are presented of a concept development study of heat rejection systems for Space Station solar dynamic power systems. The heat rejection concepts are based on recent developments in high thermal transport capacity heat pipe radiators. The thermal performance and weights of each of the heat rejection subsystems is addressed in detail, and critical technologies which require development tests and evaluation for successful demonstration are assessed and identified. Baseline and several alternate heat rejection system configurations and optimum designs are developed for both Brayton and Rankine cycles. The thermal performance, mass properties, assembly requirements, reliability, maintenance requirements and life cycle cost are determined for each configuration. A specific design was then selected for each configuration which represents an optimum design for that configuration. The final recommendations of heat rejection system configuration for either the Brayton or Rankine cycles depend on the priorities established for the evaluation criteria.

  15. Solar magnetic cycle

    NASA Technical Reports Server (NTRS)

    Harvey, Karen L.

    1993-01-01

    Using NSO/KP magnetograms, the pattern and rate of the emergence of magnetic flux and the development of the large-scale patterns of unipolar fields are considered in terms of the solar magnetic cycle. Magnetic flux emerges in active regions at an average rate of 2 x 10(exp 21) Mx/day, approximately 10 times the estimated rate in ephemeral regions. Observations are presented that demonstrate that the large-scale unipolar fields originate in active regions and activity nests. For cycle 21, the net contribution of ephemeral regions to the axial dipole moment of the Sun is positive, and is of opposite sign to that of active regions. Its amplitude is smaller by a factor of 6, assuming an average lifetime of ephemeral regions of 8 hours. Active regions larger than 4500 Mm(sup 2) are the primary contributor to the cycle variation of Sun's axial dipole moment.

  16. The global sulfur cycle

    NASA Technical Reports Server (NTRS)

    Sagan, D. (Editor)

    1985-01-01

    The results of the planetary biology microbial ecology's 1984 Summer Research Program, which examined various aspects of the global sulfur cycle are summarized. Ways in which sulfur flows through the many living and chemical species that inhabit the surface of the Earth were investigated. Major topics studied include: (1) sulfur cycling and metabolism of phototropic and filamentous sulfur bacteria; (2) sulfur reduction in sediments of marine and evaporite environments; (3) recent cyanobacterial mats; (4) microanalysis of community metabolism in proximity to the photic zone in potential stromatolites; and (5) formation and activity of microbial biofilms on metal sulfides and other mineral surfaces. Relationships between the global sulfur cycle and the understanding of the early evolution of the Earth and biosphere and current processes that affect global habitability are stressed.

  17. Superfluid thermodynamic cycle refrigerator

    DOEpatents

    Swift, Gregory W.; Kotsubo, Vincent Y.

    1992-01-01

    A cryogenic refrigerator cools a heat source by cyclically concentrating and diluting the amount of .sup.3 He in a single phase .sup.3 He-.sup.4 He solution. The .sup.3 He in superfluid .sup.4 He acts in a manner of an ideal gas in a vacuum. Thus, refrigeration is obtained using any conventional thermal cycle, but preferably a Stirling or Carnot cycle. A single phase solution of liquid .sup.3 He at an initial concentration in superfluid .sup.4 He is contained in a first variable volume connected to a second variable volume through a superleak device that enables free passage of .sup.4 He while restricting passage of .sup.3 He. The .sup.3 He is compressed (concentrated) and expanded (diluted) in a phased manner to carry out the selected thermal cycle to remove heat from the heat load for cooling below 1 K.

  18. Superfluid thermodynamic cycle refrigerator

    DOEpatents

    Swift, G.W.; Kotsubo, V.Y.

    1992-12-22

    A cryogenic refrigerator cools a heat source by cyclically concentrating and diluting the amount of [sup 3]He in a single phase [sup 3]He-[sup 4]He solution. The [sup 3]He in superfluid [sup 4]He acts in a manner of an ideal gas in a vacuum. Thus, refrigeration is obtained using any conventional thermal cycle, but preferably a Stirling or Carnot cycle. A single phase solution of liquid [sup 3]He at an initial concentration in superfluid [sup 4]He is contained in a first variable volume connected to a second variable volume through a superleak device that enables free passage of [sup 4]He while restricting passage of [sup 3]He. The [sup 3]He is compressed (concentrated) and expanded (diluted) in a phased manner to carry out the selected thermal cycle to remove heat from the heat load for cooling below 1 K. 12 figs.

  19. Component test program for variable-cycle engines

    NASA Technical Reports Server (NTRS)

    Powers, A. G.; Whitlow, J. B.; Stitt, L. E.

    1976-01-01

    Variable cycle engine (VCE) concepts for a supersonic cruise aircraft were studied. These VCE concepts incorporate unique critical components and flow path arrangements that provide good performance at both supersonic and subsonic cruise and appear to be economically and environmentally viable. Certain technologies were identified as critical to the successful development of these engine concepts and require considerable development and testing. The feasibility and readiness of the most critical VCE technologies, was assessed, a VCE component test program was initiated. The variable stream control engine (VSCE) component test program, tested and evaluated an efficient low emission duct burner and a quiet coannular ejector nozzle at the rear of a rematched F100 engine.

  20. Breaking a vicious cycle.

    PubMed

    Hayes, Daniel F; Allen, Jeff; Compton, Carolyn; Gustavsen, Gary; Leonard, Debra G B; McCormack, Robert; Newcomer, Lee; Pothier, Kristin; Ransohoff, David; Schilsky, Richard L; Sigal, Ellen; Taube, Sheila E; Tunis, Sean R

    2013-07-31

    Despite prodigious advances in tumor biology research, few tumor-biomarker tests have been adopted as standard clinical practice. This lack of reliable tests stems from a vicious cycle of undervaluation, resulting from inconsistent regulatory standards and reimbursement, as well as insufficient investment in research and development, scrutiny of biomarker publications by journals, and evidence of analytical validity and clinical utility. We offer recommendations designed to serve as a roadmap to break this vicious cycle and call for a national dialogue, as changes in regulation, reimbursement, investment, peer review, and guidelines development require the participation of all stakeholders. PMID:23903752

  1. Global water cycle

    NASA Technical Reports Server (NTRS)

    Robertson, Franklin R.; Christy, John R.; Goodman, Steven J.; Miller, Tim L.; Fitzjarrald, Dan; Lapenta, Bill; Wang, Shouping

    1991-01-01

    The primary objective is to determine the scope and interactions of the global water cycle with all components of the Earth system and to understand how it stimulates and regulates changes on both global and regional scales. The following subject areas are covered: (1) water vapor variability; (2) multi-phase water analysis; (3) diabatic heating; (4) MSU (Microwave Sounding Unit) temperature analysis; (5) Optimal precipitation and streamflow analysis; (6) CCM (Community Climate Model) hydrological cycle; (7) CCM1 climate sensitivity to lower boundary forcing; and (8) mesoscale modeling of atmosphere/surface interaction.

  2. Global water cycle

    NASA Technical Reports Server (NTRS)

    Robertson, Franklin; Goodman, Steven J.; Christy, John R.; Fitzjarrald, Daniel E.; Chou, Shi-Hung; Crosson, William; Wang, Shouping; Ramirez, Jorge

    1993-01-01

    This research is the MSFC component of a joint MSFC/Pennsylvania State University Eos Interdisciplinary Investigation on the global water cycle extension across the earth sciences. The primary long-term objective of this investigation is to determine the scope and interactions of the global water cycle with all components of the Earth system and to understand how it stimulates and regulates change on both global and regional scales. Significant accomplishments in the past year are presented and include the following: (1) water vapor variability; (2) multi-phase water analysis; (3) global modeling; and (4) optimal precipitation and stream flow analysis and hydrologic processes.

  3. Cycles in fossil diversity

    SciTech Connect

    Rohde, Robert A.; Muller, Richard A.

    2004-10-20

    It is well-known that the diversity of life appears to fluctuate during the course the Phanerozoic, the eon during which hard shells and skeletons left abundant fossils (0-542 Ma). Using Sepkoski's compendium of the first and last stratigraphic appearances of 36380 marine genera, we report a strong 62 {+-} 3 Myr cycle, which is particularly strong in the shorter-lived genera. The five great extinctions enumerated by Raup and Sepkoski may be an aspect of this cycle. Because of the high statistical significance, we also consider contributing environmental factors and possible causes.

  4. Synthetic battery cycling techniques

    NASA Technical Reports Server (NTRS)

    Leibecki, H. F.; Thaller, L. H.

    1982-01-01

    Synthetic battery cycling makes use of the fast growing capability of computer graphics to illustrate some of the basic characteristics of operation of individual electrodes within an operating electrochemical cell. It can also simulate the operation of an entire string of cells that are used as the energy storage subsystem of a power system. The group of techniques that as a class have been referred to as Synthetic Battery Cycling is developed in part to try to bridge the gap of understanding that exists between single cell characteristics and battery system behavior.

  5. Urea Cycle Disorders.

    PubMed

    Kleppe, Soledad; Mian, Asad; Lee, Brendan

    2003-07-01

    Urea cycle disorders comprise a group of inborn errors of metabolism that represent unique gene-nutrient interactions whose significant morbidity arises from acute and chronic neurotoxicity associated with often massive hyperammonemia. Current paradigms of treatment are focused on controlling the flux of nitrogen transfer through the hepatic urea cycle by a combination of dietary and pharmacologic approaches. Evolving paradigms include the development of cell and gene therapies. Current research is focused on understanding the pathophysiology of ammonia-mediated toxicity and prevention of neural injury. PMID:12791198

  6. Menstrual Cycle Effects on Attitudes toward Romantic Kissing

    PubMed Central

    Wlodarski, Rafael; Dunbar, Robin I. M.

    2015-01-01

    Hormonal changes associated with the human menstrual cycle have been previously found to affect female mate preference, whereby women in the late follicular phase of their cycle (i.e., at higher risk of conception) prefer males displaying putative signals of underlying genetic fitness. Past research also suggests that romantic kissing is utilized in human mating contexts to assess potential mating partners. The current study examined whether women in their late follicular cycle phase place greater value on kissing at times when it might help serve mate assessment functions. Using an international online questionnaire, results showed that women in the follicular phase of their menstrual cycle felt that kissing was more important at initial stages of a relationship than women in the luteal phase of their cycle. Furthermore, it was found that estimated progesterone levels were a significant negative predictor for these ratings. PMID:24078298

  7. Answering Key Fuel Cycle Questions

    SciTech Connect

    Steven J. Piet; Brent W. Dixon; J. Stephen Herring; David E. Shropshire; Mary Lou Dunzik-Gougar

    2003-10-01

    The Advanced Fuel Cycle Initiative (AFCI) program has both “outcome” and “process” goals because it must address both waste already accumulating as well as completing the fuel cycle in connection with advanced nuclear power plant concepts. The outcome objectives are waste geological repository capacity and cost, energy security and sustainability, proliferation resistance, fuel cycle economics, and safety. The process objectives are readiness to proceed and adaptability and robustness in the face of uncertainties. A classic decision-making approach to such a multi-attribute problem would be to weight individual quantified criteria and calculate an overall figure of merit. This is inappropriate for several reasons. First, the goals are not independent. Second, the importance of different goals varies among stakeholders. Third, the importance of different goals is likely to vary with time, especially the “energy future.” Fourth, some key considerations are not easily or meaningfully quantifiable at present. Instead, at this point, we have developed 16 questions the AFCI program should answer and suggest an approach of determining for each whether relevant options improve meeting each of the program goals. We find that it is not always clear which option is best for a specific question and specific goal; this helps identify key issues for future work. In general, we suggest attempting to create as many win-win decisions (options that are attractive or neutral to most goals) as possible. Thus, to help clarify why the program is exploring the options it is, and to set the stage for future narrowing of options, we have developed 16 questions, as follows: · What are the AFCI program goals? · Which potential waste disposition approaches do we plan for? · What are the major separations, transmutation, and fuel options? · How do we address proliferation resistance? · Which potential energy futures do we plan for? · What potential external triggers do we

  8. Drip Shield Emplacement Gantry Concept

    SciTech Connect

    Silva, R.A.; Cron, J.

    2000-03-29

    This design analysis has shown that, on a conceptual level, the emplacement of drip shields is feasible with current technology and equipment. A plan for drip shield emplacement was presented using a Drip Shield Transporter, a Drip Shield Emplacement Gantry, a locomotive, and a Drip Shield Gantry Carrier. The use of a Drip Shield Emplacement Gantry as an emplacement concept results in a system that is simple, reliable, and interfaces with the numerous other exising repository systems. Using the Waste Emplacement/Retrieval System design as a basis for the drip shield emplacement concept proved to simplify the system by using existing equipment, such as the gantry carrier, locomotive, Electrical and Control systems, and many other systems, structures, and components. Restricted working envelopes for the Drip Shield Emplacement System require further consideration and must be addressed to show that the emplacement operations can be performed as the repository design evolves. Section 6.1 describes how the Drip Shield Emplacement System may use existing equipment. Depending on the length of time between the conclusion of waste emplacement and the commencement of drip shield emplacement, this equipment could include the locomotives, the gantry carrier, and the electrical, control, and rail systems. If the exisiting equipment is selected for use in the Drip Shield Emplacement System, then the length of time after the final stages of waste emplacement and start of drip shield emplacement may pose a concern for the life cycle of the system (e.g., reliability, maintainability, availability, etc.). Further investigation should be performed to consider the use of existing equipment for drip shield emplacement operations. Further investigation will also be needed regarding the interfaces and heat transfer and thermal effects aspects. The conceptual design also requires further design development. Although the findings of this analysis are accurate for the assumptions made

  9. Metabolic cycle, cell cycle, and the finishing kick to Start

    PubMed Central

    Futcher, Bruce

    2006-01-01

    Slowly growing budding yeast store carbohydrate, then liquidate it in late G1 phase of the cell cycle, superimposing a metabolic cycle on the cell cycle. This metabolic cycle may separate biochemically incompatible processes. Alternatively it may provide a burst of energy and material for commitment to the cell cycle. Stored carbohydrate could explain the size requirement for cells passing the Start point. PMID:16677426

  10. Erikson's concept of ego identity reconsidered.

    PubMed

    Wallerstein, R S

    1998-01-01

    This paper explores and attempts to explain the paradox that Erik Erikson--after Freud, undoubtedly the psychoanalyst best known, most deeply esteemed, and most widely influential in the sociohistorical surround of world culture--has at the same time never been properly integrated into the psychoanalytic mainstream, but has instead been marginalized, consigned to a persisting psychoanalytic limbo. Two successive contexts within the historical unfolding of psychoanalysis in America, the milieu in which Erikson worked, would seem to account for this neglect. First, Erikson's monumental contributions to our understanding of the psychosocial developmental process, of the epigenesis of the ego, of the phase-specific developmental tasks across the eight postulated stages of the life cycle, and of the intergenerational cogwheeling of the life cycles were made during the 1950s and 1960s and could not easily be integrated into the ego psychology metapsychological paradigm then monolithically regnant within American psychoanalysis. And, second, as a major paradigm shift took place in America, beginning in the 1970s, toward a more relational, interpersonal, and intersubjective framework, Erikson's contributions, couched as they were in the structural language of the ego psychology of his time, were overlooked and went unremarked as seminal precursors of the newly emerging emphases. The clear relationship of Erikson's concepts of (ego) identity to emerging conceptions of self in relation to objects was simply not noticed, and his work continues to this day to be neglected and unintegrated within psychoanalysis. PMID:9565906

  11. [Echinococcus and strain concepts].

    PubMed

    Utük, Armağan Erdem; Simsek, Sami

    2008-01-01

    Hydatid disease (echinococcosis) is one of the most important parasitic zoonoses and remains a public health and economic problem all over the world. Echinococcus granulosus includes a number of genetic variants and, up to date, analyses of mitochondrial DNA sequences have identified ten distinct genetic types (genotypes G1-10). This categorization follows closely the pattern of strain variation emerging based on biological characteristics. The extensive variation in E. granulosus may influence life-cycle patterns, host specificity, development rate, antigenicity, transmission dynamics, sensitivity to chemotherapeutic agents, and pathology. In this review, the recent genetic characterizations of Echinococcus genus have been summarized. PMID:18351549

  12. The Modellion concept

    SciTech Connect

    Shuttleworth, W.J. )

    1991-11-01

    A model planet, Modellion, with much simpler terrestrial surfaces, have been conceived to carry out numerical experiments on the planet earth. Over the last decade, there have been observational studies to better define this model planet and to aid its evolution toward the earth system. This paper reviews these studies, their purpose, and the insight they have given; it then goes on to preview elements of the observational program proposed to occur under the Global Energy and Water Cycle Experiment and International Geosphere-Biosphere Programme in the 1990s. 52 refs.

  13. Self-Concept Is a Concept Worth Considering

    ERIC Educational Resources Information Center

    Shields, Nora

    2009-01-01

    There is a growing recognition of the importance of self-concept in the pediatric rehabilitation research literature. There also is confusion and inconsistency in the definitions of and the terminology used to describe self-concept. What is agreed is that self-concept is multidimensional, comprising a child's perception of their personal…

  14. Threshold Concepts and Conceptions: Student Learning in Introductory Management Courses

    ERIC Educational Resources Information Center

    Wright, April L.; Gilmore, Anne

    2012-01-01

    This article explores how insights from the broader education literature on threshold concepts and conceptions can be applied to improve the teaching of undergraduate introductory management courses. The authors propose that these courses are underpinned by the threshold conception, or "underlying game," that management is a practice informed by…

  15. Space Mission Concept Development Using Concept Maturity Levels

    NASA Technical Reports Server (NTRS)

    Wessen, Randii R.; Borden, Chester; Ziemer, John; Kwok, Johnny

    2013-01-01

    Over the past five years, pre-project formulation experts at the Jet Propulsion Laboratory (JPL) has developed and implemented a method for measuring and communicating the maturity of space mission concepts. Mission concept development teams use this method, and associated tools, prior to concepts entering their Formulation Phases (Phase A/B). The organizing structure is Concept Maturity Level (CML), which is a classification system for characterizing the various levels of a concept's maturity. The key strength of CMLs is the ability to evolve mission concepts guided by an incremental set of assessment needs. The CML definitions have been expanded into a matrix form to identify the breadth and depth of analysis needed for a concept to reach a specific level of maturity. This matrix enables improved assessment and communication by addressing the fundamental dimensions (e.g., science objectives, mission design, technical risk, project organization, cost, export compliance, etc.) associated with mission concept evolution. JPL's collaborative engineering, dedicated concept development, and proposal teams all use these and other CML-appropriate design tools to advance their mission concept designs. This paper focuses on mission concept's early Pre-Phase A represented by CMLs 1- 4. The scope was limited due to the fact that CMLs 5 and 6 are already well defined based on the requirements documented in specific Announcement of Opportunities (AO) and Concept Study Report (CSR) guidelines, respectively, for competitive missions; and by NASA's Procedural Requirements NPR 7120.5E document for Projects in their Formulation Phase.

  16. Re-evaluation of monitored retrievable storage concepts

    SciTech Connect

    Fletcher, J.F.; Smith, R.I.

    1989-04-01

    In 1983, as a prelude to the monitored retrievable storage (MRS) facility conceptual design, the Pacific Northwest Laboratory (PNL) conducted an evaluation for the US Department of Energy (DOE) that examined alternative concepts for storing spent LWR fuel and high- level wastes from fuel reprocessing. The evaluation was made considering nine concepts for dry away-from-reactor storage. The nine concepts evaluated were: concrete storage cask, tunnel drywell, concrete cask-in-trench, open-cycle vault, metal casks (transportable and stationary), closed-cycle vault, field drywell, and tunnel-rack vault. The purpose and scope of the re-evaluation did not require a repetition of the expert-based examinations used earlier. Instead, it was based on more detailed technical review by a small group, focusing on changes that had occurred since the initial evaluation was made. Two additional storage concepts--the water pool and the horizontal modular storage vault (NUHOMS system)--were ranked along with the original nine. The original nine concepts and the added two conceptual designs were modified as appropriate for a scenario with storage capacity for 15,000 MTU of spent fuel. Costs, area requirements, and technical and historical data pertaining to MRS storage were updated for each concept.

  17. Current concepts in osteoarthritis

    PubMed Central

    de Rezende, Márcia Uchôa; de Campos, Gustavo Constantino; Pailo, Alexandre Felício

    2013-01-01

    Osteoarthritis (OA), the most common form of joint disease, affects mainly the hips, knees, hands and feet, leading to severe disability and loss of quality of life, particularly in the elderly population. Its importance grows every year with the aging of the population, with a large increase in the elderly population compared to younger patients. The progressive understanding of the pathophysiology of OA, the perception that the process is not purely mechanical and / or aging, and clarification of the inflammatory pathways involved led recently to the clinical application of various drugs and other measures. This update aims to expose the current concepts on the pathophysiology and treatment of OA. PMID:24453655

  18. Paraterraforming - The worldhouse concept

    NASA Astrophysics Data System (ADS)

    Taylor, Richard L. S.

    1992-08-01

    This paper discusses 'paraterraforming' as a means of creating and maintaining habitable environments on other planets. The 'worldhouse' concept of paraterraforming can be formulated within the existing boundaries of technological knowledge and can provide a quasi-unconstrained global habitable environment at significantly lower levels of materials requirement and economic cost. Construction can proceed on a modular basis. A coarse-grained assessment of the possibilities of paraterraforming Mars is presented. It is suggested that the establishment of a fully habitable worldhouse environment on the planet Mercury would be a much less difficult undertaking than taerraforming Venus and could be economically important for the human exploitation of the solar system.

  19. Mars rover 1988 concepts

    NASA Technical Reports Server (NTRS)

    Pivirotto, Donna Shirley; Penn, Thomas J.; Dias, William C.

    1989-01-01

    Results of FY88 studies of a sample-collecting Mars rover are presented. A variety of rover concepts are discussed which include different technical approaches to rover functions. The performance of rovers with different levels of automation is described and compared to the science requirement for 20 to 40 km to be traversed on the Martian surface and for 100 rock and soil samples to be collected. The analysis shows that a considerable amount of automation in roving and sampling is required to meet this requirement. Additional performance evaluation shows that advanced RTG's producing 500 W and 350 WHr of battery storage are needed to supply the rover.

  20. Indian concepts on sexuality

    PubMed Central

    Chakraborty, Kaustav; Thakurata, Rajarshi Guha

    2013-01-01

    India is a vast country depicting wide social, cultural and sexual variations. Indian concept of sexuality has evolved over time and has been immensely influenced by various rulers and religions. Indian sexuality is manifested in our attire, behavior, recreation, literature, sculptures, scriptures, religion and sports. It has influenced the way we perceive our health, disease and device remedies for the same. In modern era, with rapid globalization the unique Indian sexuality is getting diffused. The time has come to rediscover ourselves in terms of sexuality to attain individual freedom and to reinvest our energy to social issues related to sexuality. PMID:23858263

  1. CONCEPT ANALYSIS: AGGRESSION

    PubMed Central

    Liu, Jianghong

    2006-01-01

    The concept of aggression is important to nursing because further knowledge of aggression can help generate a better theoretical model to drive more effective intervention and prevention approaches. This paper outlines a conceptual analysis of aggression. First, the different forms of aggression are reviewed, including the clinical classification and the stimulus-based classification. Then the manifestations and measurement of aggression are described. Finally, the causes and consequences of aggression are outlined. It is argued that a better understanding of aggression and the causal factors underlying it are essential for learning how to prevent negative aggression in the future. PMID:15371137

  2. The emittance concept

    NASA Astrophysics Data System (ADS)

    Lawson, J. D.

    1992-04-01

    An informal descriptive account is first given of the emittance concept and its underlying physical basis. This is followed by a discussion of the connection between emittance and entropy, and a number of questions relating to problems of current interest concerning such topics as emittance growth and equipartition between different degrees of freedom are raised. Although no new results are obtained, it is hoped that the discussion may be helpful in the search for new insights. The paper differs from that presented at the conference, and contains ideas which arose in discussion with T. P. Wangler at Los Alamos after the conference.

  3. Open airscrew VTOL concepts

    NASA Technical Reports Server (NTRS)

    Stepniewski, W. Z.; Tarczynski, T.

    1992-01-01

    The following concepts, based on using open airscrew(s) for VTOL maneuvers, are re-examined in light of current technology: (1) tip-driven helicopters, (2) compound helicopters; and (3) high-speed VTOL aircraft, represented by tiltrotors, tiltwings, retractoplanes and stoppable rotors. Criteria, permitting one to compare performance of aircraft using diverse lifting and propelling methods are established. Determination of currently possible performance, indication of near-future potentials, and comparison of those items with the baseline levels (as represented by contemporary shaft-driven helicopters, first generation tiltrotors, and commercial turboprop fixed-wind aircraft) constitutes bulk of this report.

  4. Concept analysis: aggression.

    PubMed

    Liu, Jianghong

    2004-01-01

    The concept of aggression is important to nursing because further knowledge of aggression can help generate a better theoretical model to drive more effective intervention and prevention approaches. This paper outlines a conceptual analysis of aggression. First, the different forms of aggression are reviewed, including the clinical classification and the stimulus-based classification. Then the manifestations and measurement of aggression are described. Finally, the causes and consequences of aggression are outlined. It is argued that a better understanding of aggression and the causal factors underlying it are essential for learning how to prevent negative aggression in the future. PMID:15371137

  5. A model regenerator for a Stirling cycle

    NASA Astrophysics Data System (ADS)

    Carolan, James

    2001-05-01

    An essential feature of the engine patented by Robert Stirling in 1817 was the careful description of the idea of regeneration. In the standard thermodynamic cycle representation of the engine, regeneration is the storing and the reusing of the thermal energy released in the constant volume cooling part of the cycle. Due to the difficulty in treating regeneration quantitatively, introductory physics texts generally either ignore the concept or assume the regeneration to be perfect. As a result students obtain little or no understanding of regeneration. In addition there seem to be differing views in various texts about the efficiency of Stirling engines. In this work a simple finite element model regenerator is presented with which one can do simple calculations. The model does not accurately represent actual regeneration in a practical engine. But the model might help students gain better insight into Stirling engine efficiency and the idea of regeneration.

  6. THE C2 OXIDATIVE PHOTOSYNTHETIC CARBON CYCLE.

    PubMed

    Tolbert, N. E.

    1997-06-01

    The C2 oxidative photosynthetic carbon cycle plus the C3 reductive photosynthetic carbon cycle coexist. Both are initiated by Rubisco, use about equal amounts of energy, must regenerate RuBP, and result in exchanges of CO2 and O2 to establish rates of net photosynthesis, CO2 and O2 compensation points, and the ratio of CO2 and O2 in the atmosphere. These concepts evolved from research on O2 inhibition, glycolate metabolism, leaf peroxisomes, photorespiration, 18O2/16O2 exchange, CO2 concentrating processes, and a requirement for the oxygenase activity of Rubisco. Nearly 80 years of research on these topics are unified under the one process of photosynthetic carbon metabolism and its self-regulation. PMID:15012254

  7. MERCURY CYCLING AND BIOMAGNIFICATION

    EPA Science Inventory

    Mercury cycling and biomagnification was studied in man-made ponds designed for watering livestock on the Cheyenne River Sioux Reservation in South Dakota. Multiple Hg species were quantified through multiple seasons for 2 years in total atmospheric deposition samples, surface wa...

  8. Assisted Cycling Tours

    ERIC Educational Resources Information Center

    Hollingsworth, Jan Carter

    2008-01-01

    This article discusses Assisted Cycling Tours (ACT), a Westminster, Colorado based 501(c)3, non-profit that is offering the joy of bicycle tours in breathtaking, scenic locations to children and adults with developmental and physical disabilities and their families. ACT was founded by Bob Matter and his son David with a goal of opening up the…

  9. Rapid cycling superconducting magnets

    NASA Astrophysics Data System (ADS)

    Fabbricatore, P.; Farinon, S.; Gambardella, U.; Greco, M.; Volpini, G.

    2006-04-01

    The paper deals with the general problematic related to the development of fast cycled superconducting magnets for application in particle accelerator machines. Starting from the requirements of SIS300 synchrotron under design at GSI and an envisaged future Super-SPS injector at CERN, it is shown which developments are mandatory in the superconducting wire technology and in the magnet design field.

  10. Stirling cycle piston engine

    SciTech Connect

    Morgan, G. R.

    1985-02-12

    This device is an improvement over the conventional type of Stirling cycle engine where the expander piston is connected to a crankshaft and the displacer piston is connected to the same or another crankshaft for operation. The improvement is based on both the expansion and displacer pistons being an integral unit having regenerating means which eliminate the mechanisms that synchronize the regeneration mode.

  11. The Science of Cycling

    ERIC Educational Resources Information Center

    Crompton, Zoe; Daniels, Shelley

    2014-01-01

    Children are engaged by finding out about science in the real world (Harlen, 2010). Many children will be cyclists or will have seen or heard about the success of British cyclists in the Olympics and the Tour de France. This makes cycling a good hook to draw children into learning science. It is also a good cross-curricular topic, with strong…

  12. Re-Cycling

    ERIC Educational Resources Information Center

    Brown, Robert W.; Covault, Corbin E.

    2015-01-01

    An old comedy routine on Saturday Night Live by Father Guido Sarducci introduced a "Five-Minute University," because five minutes is all that's remembered after graduation anyway. In counterpoint, we discuss "cycling," a teaching method for memory enhancement. Our principal implementation consists of offering a simple version…

  13. LIFE-CYCLE ASSESSMENT

    EPA Science Inventory

    Life Cycle Assessment, or LCA, is an environmental accounting and mangement approach that consider all the aspects of resource use and environmental releases associated with an industrial system from cradle-to-grave. Specifically, it is a holistic view of environmental interacti...

  14. 90-Day Cycle Handbook

    ERIC Educational Resources Information Center

    Park, Sandra; Takahashi, Sola

    2013-01-01

    90-Day Cycles are a disciplined and structured form of inquiry designed to produce and test knowledge syntheses, prototyped processes, or products in support of improvement work. With any type of activity, organizations inevitably encounter roadblocks to improving performance and outcomes. These barriers might include intractable problems at…

  15. The Geologic Nitrogen Cycle

    NASA Astrophysics Data System (ADS)

    Johnson, B. W.; Goldblatt, C.

    2013-12-01

    N2 is the dominant gas in Earth's atmosphere, and has been so through the majority of the planet's history. Originally thought to only be cycled in significant amounts through the biosphere, it is becoming increasingly clear that a large degree of geologic cycling can occur as well. N is present in crustal rocks at 10s to 100s of ppm and in the mantle at 1s to perhaps 10s of ppm. In light of new data, we present an Earth-system perspective of the modern N cycle, an updated N budget for the silicate Earth, and venture to explain the evolution of the N cycle over time. In an fashion similar to C, N has a fast, biologically mediated cycle and a slower cycle driven by plate tectonics. Bacteria fix N2 from the atmosphere into bioavailable forms. N is then cycled through the food chain, either by direct consumption of N-fixing bacteria, as NH4+ (the primary waste form), or NO3- (the most common inorganic species in the modern ocean). Some organic material settles as sediment on the ocean floor. In anoxic sediments, NH4+ dominates; due to similar ionic radii, it can readily substitute for K+ in mineral lattices, both in sedimentary rocks and in oceanic lithosphere. Once it enters a subduction zone, N may either be volatilized and returned to the atmosphere at arc volcanoes as N2 or N2O, sequestered into intrusive igneous rocks (as NH4+?), or subducted deep into the mantle, likely as NH4+. Mounting evidence indicates that a significant amount of N may be sequestered into the solid Earth, where it may remain for long periods (100s m.y.) before being returned to the atmosphere/biosphere by volcanism or weathering. The magnitude fluxes into the solid Earth and size of geologic N reservoirs are poorly constrained. The size of the N reservoirs contained in the solid Earth directly affects the evolution of Earth's atmosphere. It is possible that N now sequestered in the solid Earth was once in the atmosphere, which would have resulted in a higher atmospheric pressure, and

  16. Carbon Cycling with Nuclear Power

    NASA Astrophysics Data System (ADS)

    Lackner, Klaus S.

    2011-11-01

    Liquid hydrocarbon fuels like gasoline, diesel or jet fuel are the most efficient ways of delivering energy to the transportation sector, in particular cars, ships and airplanes. Unfortunately, their use nearly unavoidably leads to the emission of carbon dioxide into the atmosphere. Unless an equivalent amount is removed from the air, the carbon dioxide will accumulate and significantly contribute to the man-made greenhouse effect. If fuels are made from biomass, the capture of carbon dioxide is a natural part of the cycle. Here, we discuss technical options for capturing carbon dioxide at much faster rates. We outline the basic concepts, discuss how such capture technologies could be made affordable and show how they could be integrated into a larger system approach. In the short term, the likely source of the hydrocarbon fuels is oil or gas; in the longer term, technologies that can provide energy to remove oxygen from carbon dioxide and water molecules and combine the remaining components into liquid fuels make it possible to recycle carbon between fuels and carbon dioxide in an entirely abiotic process. Here we focus on renewable and nuclear energy options for producing liquid fuels and show how air capture combined with fuel synthesis could be more economic than a transition to electric cars or hydrogen-fueled cars.

  17. A Systems Development Life Cycle Project for the AIS Class

    ERIC Educational Resources Information Center

    Wang, Ting J.; Saemann, Georgia; Du, Hui

    2007-01-01

    The Systems Development Life Cycle (SDLC) project was designed for use by an accounting information systems (AIS) class. Along the tasks in the SDLC, this project integrates students' knowledge of transaction and business processes, systems documentation techniques, relational database concepts, and hands-on skills in relational database use.…

  18. Teaching Angiosperm Reproduction by Means of the Learning Cycle.

    ERIC Educational Resources Information Center

    Scharmann, Lawrence C.

    1991-01-01

    Discussed is an alternative teaching strategy to uncover and assess a common misconception in the life sciences and to articulate its use in teaching a unit on angiosperm reproduction. The learning cycle is described, and a concept map on reproduction on angiosperms is included. (KR)

  19. Elements of the iron and manganese cycles in Lake Baikal

    USGS Publications Warehouse

    Granina, L.Z.; Callender, E.

    2007-01-01

    Using data obtained in recent years, we considered the external mass balance and characteristics of internal iron and manganese cycles in Lake Baikal (biological uptake, remineralization, sedimentary and diffusive fluxes, accumulation in sediments, time of renewal, etc.). Some previous results and common concepts were critically reevaluated. ?? Pleiades Publishing, Ltd. 2007.

  20. Preparing the DSN operations concepts

    NASA Technical Reports Server (NTRS)

    Salazar, A. J.; Bailey, M. D.; Kuo, N. R.; Wilkinson, B. M.

    1993-01-01

    Operations concepts are prepared to support a specific application and can, therefore, be classified accordingly. Studies of NASA and military operations concepts suggest three major types: data services, customer services, and systems oriented. Data services concepts concentrate on data types (e.g., telemetry and command) and how these data are processed and delivered to the user. Such concepts are normally used by data-processing centers to describe data-coding schemes and data formats. Customer services concepts concentrate on the customers' requirements and describe how these requirements are met using the systems available to the operation. Project centers use such concepts to describe the various types of data as they flow from the source (e.g., a spacecraft) to the end user (i.e., the customer). Systems oriented concepts concentrate on the use of systems for processing and delivering customer data. This paper examines the latter type and the 'concepts' that are inherent within them.

  1. Measuring the Concept of Credibility.

    ERIC Educational Resources Information Center

    Gaziano, Cecilie; McGrath, Kristin

    1986-01-01

    Describes measurement of the concept of media credibility in previous research and reports results of a national survey that treated credibility as a multidimensional concept. Concludes from factor analysis that credibility scores for newspapers and television news were correlated. (FL)

  2. Retrieval for color artistry concepts.

    PubMed

    Lay, Jose A; Guan, Ling

    2004-03-01

    This paper presents a work on the retrieval of artworks for color artistry concepts. First we affirm the view that the Query-by-Example paradigm fundamental to the current content-based retrieval systems is able to extend only limited usefulness. We then propose a concept-based retrieval engine based on the generative grammar of elemental concepts methodology. In the latter, the language by which color artistry concepts are communicated in artworks is used to operate semantic searches. The color artistry language is explicated into elemental concepts and the associated generative grammar. The elemental concepts are used to index the artworks, while the generative grammar is used to facilitate post-coordinate expression of color artistry concept queries by using the elemental concepts. PMID:15376925

  3. La recherche de naines brunes autour d'etoiles du voisinage solaire et le spectrographe multi-objets SIMON

    NASA Astrophysics Data System (ADS)

    Albert, Loic

    Cette thèse comporte un volet d'instrumentation astronomique, le spectrographe infrarouge SIMON, et un volet de recherche, la recherche de naines brunes autour d'étoiles (lu voisinage solaire. Le premier volet fait état de la construction du Spectrographe infrarouge de Montréal (SIMON), un instrument polyvalent fonctionnant dans le proche infrarouge (0.8-2.5 [mu]m) conçu pour être utilisé à l'Observatoire du mont Mégantic (OMM) et au télescope Canada-France-Hawaii (TCFH). SIMON regroupe plusieurs fonctionnalités: l'irnagerie, la spectroscopie, la spectroscopie rnulti-objets et la polarimétrie. Comme imageur, il offre un champ de vue (le 7.7'x 7.7' à l'OMM et 3.3' x 3.3' au TCFH et possède huit filtres dont un filtre I . SIMON compte trois disperseurs pour la spectroscopie: (1) un prisme d'Amici R max [approximate]50, 0.8-2.5 [mu]m); (2) un grism de silice (R max [approximate]750, 1.17-2.34 [mu]m); et un grism de KRS-5 (R max [approximate]3000, bande J,H ou K S ). Le mode spectroscopique multi-objets utilise des masques cryogéniques placés dans un second cryostat et, couplé au prisme d'Amici, permet l'obtention d'une centaine de spectres simultanément. Le mode polarimétrique permet l'observation de quatre vecteurs de polarisation simultanément. Cette première moitié de thèse étaye les objectifs scientifiques, détaille la conception optique (collimatrice et caméra) et mécanique (un cryostat principal contenant trois cotres à filtres et le détecteur, un cryostat amovible contenant nue roue à masques), décrit l'électronique et le système d'acquisition, et enfin présente les performances dans les différents modes. Le second volet de cette thèse est un relevé grand champ à la recherche de naines brunes de type T autour de 66 étoiles du voisinage solaire. Il a été effectué en utilisant des caméras infrarouges (dont SIMON) et des CCD sur divers télescopes. Le diagramme I--J vs. J--H utilisé est. efficace pour isoler des naines T

  4. Portevin-Le Chatelier effect under cyclic loading: experimental and numerical investigations

    NASA Astrophysics Data System (ADS)

    Mazière, M.; Pujol d'Andrebo, Q.

    2015-10-01

    The Portevin-Le Chatelier (PLC) effect is generally evidenced by the apparition of serrated yielding under monotonic tensile loading conditions. It appears at room temperature in some aluminium alloys, around ? in some steels and in many other metallic materials. This effect is associated with the propagation of bands of plastic deformation in tensile specimens and can in some cases lead to unexpected failures. The PLC effect has been widely simulated under monotonic conditions using finite elements and an appropriate mechanical model able to reproduce serrations and strain localization. The occurrence of serrations can be predicted using an analytical stability analysis. Recently, this serrated yielding has also been observed in specimens made of Cobalt-based superalloy under cyclic loading, after a large number of cycles. The mechanical model has been identified in this case to accurately reproduce this critical number of cycle where serrations appear. The associated apparition of localized bands of deformation in specimens and their influence on its failure has also been investigated using finite element simulations.

  5. Modular reflector concept study

    NASA Technical Reports Server (NTRS)

    Vaughan, D. H.

    1981-01-01

    A study was conducted to evaluate the feasibility of space erecting a 100 meter paraboloidal radio frequency reflector by joining a number of individually deployed structural modules. Three module design concepts were considered: (1) the deployable cell module (DCM); (2) the modular paraboloidal erectable truss antenna (Mod-PETA); and (3) the modular erectable truss antenna (META). With the space shuttle (STS) as the launch system, the methodology of packaging and stowing in the orbiter, and of dispensing, deploying and joining, in orbit, were studied and the necessary support equipment identified. The structural performance of the completed reflectors was evaluated and their overall operational capability and feasibility were evaluated and compared. The potential of the three concepts to maintain stable shape in the space environment was determined. Their ability to operate at radio frequencies of 1 GHz and higher was assessed assuming the reflector surface to consist of a number of flat, hexagonal facets. A parametric study was performed to determine figure degradation as a function of reflector size, flat facet size, and f/D ratio.

  6. Mobile Lunar Base Concepts

    NASA Astrophysics Data System (ADS)

    Cohen, Marc M.

    2004-02-01

    This paper describes three innovative concepts for a mobile lunar base. These concept combine design research for habitat architecture, mobility systems, habitability, radiation protection, human factors, and living and working environments on the lunar surface. The mobile lunar base presents several key advantages over conventional static base notions. These advantages concern landing zone safety, the requirement to move modules over the lunar surface, and the ability to stage mobile reconnaissance with effective systemic redundancy. All of these concerns lead to the consideration of a mobile walking habitat module and base design. The key issues involve landing zone safety, the ability to transport habitat modules across the surface, and providing reliability and redundancy to exploration traverses in pressurized vehicles. With self-ambulating lunar base modules, it will be feasible to have each module separate itself from its retro-rocket thruster unit, and walk five to ten km away from the LZ to a pre-selected site. These mobile modules can operate in an autonomous or teleoperated mode to navigate the lunar surface. At the site of the base, the mobile modules can combine together; make pressure port connections among themselves, to create a multi-module pressurized lunar base.

  7. PRSEUS Structural Concept Development

    NASA Technical Reports Server (NTRS)

    Velicki, Alex; Jegley, Dawn

    2014-01-01

    A lighter, more robust airframe is one of the key technological advancements necessary for the successful launch of any large next-generation transport aircraft. Such a premise dictates that considerable improvements beyond current state-of-the-art aluminum structures is needed, and that improvements of this magnitude will require an extensive use of composite materials that are not only lightweight, but also economical to produce. To address this challenge, researchers at NASA and The Boeing Company are developing a novel structural concept called the Pultruded Rod Stitched Efficient Unitized Structure (PRSEUS) under the Environmentally Responsible Aviation (ERA) Project. It is an integrally stiffened panel concept that is stitched together and designed to maintain residual load-carrying capabilities under a variety of damage scenarios. In addition to improved structural performance, an important facet of this unique arrangement of stitched carbon fibers is its innovative manufacturing method that has the potential to lower fabrication costs by eliminating fasteners and autoclave cures. The rationale and development status for this new approach forms the basis of the work described in this paper. The test specimens described herein were fabricated, or are currently being fabricated, by The Boeing Company, while the structural analyses and testing tasks are being performed by NASA and Boeing personnel.

  8. Advanced microwave processing concepts

    SciTech Connect

    Lauf, R.J.; McMillan, A.D.; Paulauskas, F.L.

    1997-04-01

    The purpose of this work is to explore the feasibility of several advanced microwave processing concepts to develop new energy-efficient materials and processes. The project includes two tasks: (1) commercialization of the variable-frequency microwave furnace; and (2) microwave curing of polymeric materials. The variable frequency microwave furnace, whose initial conception and design was funded by the AIM Materials Program, allows the authors, for the first time, to conduct microwave processing studies over a wide frequency range. This novel design uses a high-power traveling wave tube (TWT) originally developed for electronic warfare. By using this microwave source, one can not only select individual microwave frequencies for particular experiments, but also achieve uniform power densities over a large area by the superposition of many different frequencies. Microwave curing of various thermoset resins will be studied because it holds the potential of in-situ curing of continuous-fiber composites for strong, lightweight components or in-situ curing of adhesives, including metal-to-metal. Microwave heating can shorten curing times, provided issues of scaleup, uniformity, and thermal management can be adequately addressed.

  9. Advanced microwave processing concepts

    SciTech Connect

    Lauf, R.J.; McMillan, A.D.; Paulauskas, F.L.

    1995-05-01

    The purpose of this work is to explore the feasibility of several advanced microwave processing concepts to develop new energy-efficient materials and processes. The project includes two tasks: (1) commercialization of the variable-frequency microwave furnace; and (2) microwave curing of polymer composites. The variable frequency microwave furnace, whose initial conception and design was funded by the AIC Materials Program, will allow us, for the first time, to conduct microwave processing studies over a wide frequency range. This novel design uses a high-power traveling wave tube (TWT) originally developed for electronic warfare. By using this microwave source, one can not only select individual microwave frequencies for particular experiments, but also achieve uniform power densities over a large area by the superposition of many different frequencies. Microwave curing of thermoset resins will be studied because it hold the potential of in-situ curing of continuous-fiber composites for strong, lightweight components. Microwave heating can shorten curing times, provided issues of scaleup, uniformity, and thermal management can be adequately addressed.

  10. Review of concepts of stability

    NASA Astrophysics Data System (ADS)

    Szebehely, V.

    1984-12-01

    Concepts of stability are reviewed, emphasizing global aspects as well as specific applications to dynamics and celestial mechanics. Historical and fundamental aspects of the concept of stability are discussed, and major stability concepts are examined, including Hill's stability, Liapunov's and Poincare's stability, and Kolmogorov's tori. Short definitions are given of various concepts and terminologies used in stability research. Problems of fundamental importance are identified and lines of future research are suggested.

  11. Using the Learning Cycle To Teach Physical Science: A Hands-on Approach for the Middle Grades.

    ERIC Educational Resources Information Center

    Beisenherz, Paul; Dantonio, Marylou

    The Learning Cycle Strategy enables students themselves to construct discrete science concepts and includes an exploration phase, introduction phase, and application phase. This book focuses on the use of the Learning Cycle to teach physical sciences and is divided into three sections. Section I develops a rationale for the Learning Cycle as an…

  12. Online Exhibits & Concept Maps

    NASA Astrophysics Data System (ADS)

    Douma, M.

    2009-12-01

    Presenting the complexity of geosciences to the public via the Internet poses a number of challenges. For example, utilizing various - and sometimes redundant - Web 2.0 tools can quickly devour limited time. Do you tweet? Do you write press releases? Do you create an exhibit or concept map? The presentation will provide participants with a context for utilizing Web 2.0 tools by briefly highlighting methods of online scientific communication across several dimensions. It will address issues of: * breadth and depth (e.g. from narrow topics to well-rounded views), * presentation methods (e.g. from text to multimedia, from momentary to enduring), * sources and audiences (e.g. for experts or for the public, content developed by producers to that developed by users), * content display (e.g. from linear to non-linear, from instructive to entertaining), * barriers to entry (e.g. from an incumbent advantage to neophyte accessible, from amateur to professional), * cost and reach (e.g. from cheap to expensive), and * impact (e.g. the amount learned, from anonymity to brand awareness). Against this backdrop, the presentation will provide an overview of two methods of online information dissemination, exhibits and concept maps, using the WebExhibits online museum (www.webexhibits.org) and SpicyNodes information visualization tool (www.spicynodes.org) as examples, with tips on how geoscientists can use either to communicate their science. Richly interactive online exhibits can serve to engage a large audience, appeal to visitors with multiple learning styles, prompt exploration and discovery, and present a topic’s breadth and depth. WebExhibits, which was among the first online museums, delivers interactive information, virtual experiments, and hands-on activities to the public. While large, multidisciplinary exhibits on topics like “Color Vision and Art” or “Calendars Through the Ages” require teams of scholars, user interface experts, professional writers and editors

  13. Teachers' understanding and the use of the learning cycle

    NASA Astrophysics Data System (ADS)

    Marek, Edmund A.; Eubanks, Carol; Gallaher, Thomas H.

    1990-12-01

    This study examined the relationships that exist between high school science teachers' understanding of the Piagetian developmental model of intelligence, its inherent teaching procedure - the learning cycle - and classroom teaching practices. The teachers observed in this study had expressed dissatisfaction with the teaching methods they used, and, subsequently, attended a National Science Foundation sponsored in-service program designed to examine laboratory-centered science curricula and the educational and scientific theories upon which the curricula were based. The teachers who exhibited a sound understanding of the Piagetian model of intelligence and the learning cycle were more likely to effectively implement learning cycle curricula. They were able to successfully integrate their students' laboratory experiences with class discussions to construct science concepts. The teachers who exhibited misunderstandings of the Piagetian developmental model of intelligence and the learning cycle also engaged their students in laboratory activities, but these activities were weakly related to learning cycles. For example, the data gathered by their students were typically not used in class discussions to construct science concepts. Therefore, these teachers apparently did not discern the necessity of using the data and experiences from laboratory activities as the impetus for science concept attainment. Additional results comparing degrees of understanding, teaching behaviors and questioning strategies are discussed.

  14. Restorative Justice Scripts in Ursula K. Le Guin's "Voices"

    ERIC Educational Resources Information Center

    Oziewicz, Marek C.

    2011-01-01

    This essay examines restorative justice scripting in "Voices", the second volume of Ursula K. Le Guin's "Annals of the Western Shore." Narrated by a rape-child, "Voices" is the story of an occupied city-state and of how the conquered and the conquerors negotiate a formula for peaceful coexistence. They are able to do so by enacting a restorative…

  15. Decolonizing the Choctaws: Teaching LeAnne Howe's "Shell Shaker"

    ERIC Educational Resources Information Center

    Hollrah, Patrice

    2004-01-01

    "Shell Shaker" (2001) by LeAnne Howe (Choctaw) is a novel that gives students an opportunity to learn that the history and culture of the Choctaw Nation of Oklahoma are alive today. Winner of the Before Columbus Foundation American Book Award in 2002, the novel deals with two parallel stories that converge in the present, one about the eighteenth…

  16. Le Dernier Cartoucherie: Refuge and the Performance of Care

    ERIC Educational Resources Information Center

    Fisek, Emine

    2008-01-01

    In 2003, the Paris-based theatre company Theatre du Soleil launched "Le Dernier Caravanserail: Odyssees", a collaborative creation based on stories that company members had collected from refugees at the Sangatte refugee camp outside Calais, among other locations. Scenes of moral reasoning dotted the six-hour spectacle, calling to mind the…

  17. Ursula LeGuin's Magical World of Earthsea.

    ERIC Educational Resources Information Center

    Griffin, Jan M.

    1996-01-01

    Discusses how Ursula LeGuin's Earthsea Trilogy reflects her belief in Taoist philosophy as well as her skill in telling stories of magic and adventure. Notes that the three books can be described as coming-of-age novels in which three separate individuals struggle to become mature, responsible, whole adults. (RS)

  18. MoLeNET Mobile Learning Conference 2009: Research Papers

    ERIC Educational Resources Information Center

    Guy Parker, Ed.

    2010-01-01

    The Mobile Learning Network (MoLeNET) is a unique collaborative approach to encouraging, supporting, expanding and promoting mobile learning, primarily in English post-14 education and training, via supported shared cost mobile learning projects. Collaboration at national level involves participating institutions and the Learning and Skills…

  19. LHC, le Big Bang en éprouvette

    ScienceCinema

    None

    2011-10-06

    Notre compréhension de l?Univers est en train de changer? Bar des Sciences - Tout public Débat modéré par Marie-Odile Montchicourt, journaliste de France Info. Evenement en vidéoconférence entre le Globe de la science et de l?innovation, le bar le Baloard de Montpellier et la Maison des Métallos à Paris. Intervenants au CERN : Philippe Charpentier et Daniel Froideveaux, physiciens au CERN. Intervenants à Paris : Vincent Bontemps, philosophe et chercheur au CEA ; Jacques Arnould, philosophe, historien des sciences et théologien, Jean-Jacques Beineix, réalisateur, producteur, scénariste de cinéma. Intervenants à Montpellier (LPTA) : André Neveu, physicien théoricien et directeur de recherche au CNRS ; Gilbert Moultaka, physicien théoricien et chargé de recherche au CNRS. Partenariat : CERN, CEA, IN2P3, Université MPL2 (LPTA) Dans le cadre de la Fête de la science 2008

  20. Understanding of earth and space science concepts: Strategies for concept building in elementary teacher preparation

    NASA Astrophysics Data System (ADS)

    Bulunuz, Nermin

    Research on conceptual change provides strong evidence that not only children but also many adults have incorrect or incomplete understanding of science concepts. This mixed methods study was concerned with preservice and inservice teachers' understanding of six earth and space science concepts commonly taught in elementary school: reasons for seasons, phases of the moon, reasons for the wind, the rock cycle, soil formation, and earthquakes. The first part of the study determined and compared the level of conceptual understanding held by both groups on topics they will need to teach in the Georgia Performance Standards [GPS]. The second part focused on whether readings or hands-on learning stations, in some cases combined with concept mapping, improves preservice teachers' understanding of these concepts. The third part described the application of conceptual change strategies of one group of preservice teachers during their field placements. The overall sample was two cohorts of preservice teachers, one cohort of preservice teachers from an alternative initial certification program, and two masters' cohorts consisting of inservice teachers. Four data sources were: a six item open-ended survey, concept maps, the field assignments, and the researcher's field notes. Rubrics were used to score answers to each survey question. Concept map scores were calculated based on the criteria developed by Novak and Gowin (1984). The first part of the study shows that both preservice and inservice teachers have low conceptual understanding of the earth science concepts taught in elementary school. Independent samples t-tests results indicate that both groups have similar understanding about these concepts. A two way ANOVA with repeated measures analysis demonstrated that readings and learning stations are both successful in building preservice teacher's understanding and that benefits from the hands-on learning stations approached statistical significance. A paired samples t

  1. The Lexicography of Scholarly Concepts.

    ERIC Educational Resources Information Center

    McInnis, Raymond G.

    1995-01-01

    Discusses the function of concepts in scholarly discourse. Topics include the genesis of Greenwood Press's concept dictionaries; the origins of modern rhetoric; the prescriptive nature of meaning in scholarly discourse; conceptual change, including logical positivism, introspection, and historicism; and interdisciplinary application of concepts.…

  2. The Concept of Philosophical Education

    ERIC Educational Resources Information Center

    Boyum, Steinar

    2010-01-01

    Strangely, the concept of philosophical education is not much in use, at least not as a "philosophical" concept. In this essay, Steinar Boyum attempts to outline such a philosophical concept of philosophical education. Boyum uses Plato's Allegory of the Cave, Rene Descartes's life of doubt, and Immanuel Kant's criticism of metaphysics as paradigms…

  3. Can We Feel Physics Concepts?

    ERIC Educational Resources Information Center

    Su, Yucheng

    2010-01-01

    There are many ways to improve students' understanding of physics concepts. This article focused on drawing students' attention with picture-embedded questions. Pictures give students a direct impression or feeling about the corresponding concepts, which really makes a difference. However, the effects are limited. Some physics concepts are…

  4. Teachers' Conceptions of Tangent Line

    ERIC Educational Resources Information Center

    Paez Murillo, Rosa Elvira; Vivier, Laurent

    2013-01-01

    In order to study the conceptions, and their evolutions, of the tangent line to a curve an updating workshop which took place in Mexico was designed for upper secondary school teachers. This workshop was planned using the methodology of cooperative learning, scientific debate and auto reflection (ACODESA) and the conception-knowing-concept model…

  5. Nonstandard Student Conceptions about Infinitesimals

    ERIC Educational Resources Information Center

    Ely, Robert

    2010-01-01

    This is a case study of an undergraduate calculus student's nonstandard conceptions of the real number line. Interviews with the student reveal robust conceptions of the real number line that include infinitesimal and infinite quantities and distances. Similarities between these conceptions and those of G. W. Leibniz are discussed and illuminated…

  6. Concept Learning through Image Processing.

    ERIC Educational Resources Information Center

    Cifuentes, Lauren; Yi-Chuan, Jane Hsieh

    This study explored computer-based image processing as a study strategy for middle school students' science concept learning. Specifically, the research examined the effects of computer graphics generation on science concept learning and the impact of using computer graphics to show interrelationships among concepts during study time. The 87…

  7. Concepts of Chinese Folk Happiness

    ERIC Educational Resources Information Center

    Ip, Po Keung

    2011-01-01

    Discourses on Chinese folk happiness are often based on anecdotal narratives or qualitative analysis. Two traditional concepts of happiness popular in Chinese culture are introduced. The paper constructs a concept of Chinese folk happiness on basis of the findings of a scientific survey on the Taiwanese people regarding their concepts of…

  8. Le syndrome d'embolie graisseuse post traumatique

    PubMed Central

    Berdai, Adnane Mohamed; Shimi, Abdelkarim; Khatouf, Mohammed

    2014-01-01

    Le syndrome d'embolie graisseuse est une complication grave des fractures des os longs, il est la conséquence de la dissémination des particules graisseuses dans la microcirculation. L'objectif de ce travail est de déterminer le profil épidémiologique, la présentation clinique et paraclinique de ce syndrome et sa prise en charge thérapeutique. Notre étude porte sur 11 cas de syndrome d'embolie graisseuse colligés au service de réanimation A1 au centre hospitalier universitaire Hassan II de Fès, de Janvier 2009 à Juin 2012. Le diagnostic positif est basé sur les critères de Gurd. Les cas collectés se caractérisent par la prédominance du sexe masculin, d'un âge inférieur à 40 ans, présentant une fracture fémorale. Ce syndrome survient souvent dans les 72 heures après le traumatisme. La présentation clinique est dominée par l'hypoxémie et les troubles de conscience. Sur le plan biologique: l'anémie et la thrombopénie sont les manifestations les plus fréquentes. La prise en charge est symptomatique, 63% des patients ont nécessité l'intubation et la ventilation. L’évolution n'est pas toujours bénigne. Nos résultats confirme le polymorphisme de la présentation clinique et paraclinique du syndrome d'embolie graisseuse. Le diagnostic de ce syndrome se base sur des critères cliniques, mais reste essentiellement un diagnostic d’élimination. La prise en charge est symptomatique. La prévention de ce syndrome est essentielle et se base sur une fixation précoce des fractures des os longs. PMID:25452829

  9. Connecting Instructional and Cognitive Aspects of an LE: A Study of the Global Seminar Project

    ERIC Educational Resources Information Center

    Savelyeva, Tamara

    2012-01-01

    My research problem is based on the lack of unifying conceptual cohesion between the discourses concerning cognitive and instructional aspects of learning environments (LE). I contrast that lack with practical developments of LE studies connected at the level of practical implementation and evaluation. Next, I briefly review the LE boundaries,…

  10. Population exposure from the fuel cycle: Review and future direction

    SciTech Connect

    Richmond, C.R.

    1987-01-01

    The legacy of radiation exposures confronting man arises from two historical sources of energy, the sun and radioactive decay. Contemporary man continues to be dependent on these two energy sources, which include the nuclear fuel cycle. Radiation exposures from all energy sources should be examined, with particular emphasis on the nuclear fuel cycle, incidents such as Chernobyl and Three Mile Island. In addition to risk estimation, concepts such as de minimis, life shortening as a measure of risk, and competing risks as projected into the future must be considered in placing radiation exposures in perspective. The utility of these concepts is in characterizing population exposures for decision makers in a manner that the public may judge acceptable. All these viewpoints are essential in the evaluation of population exposure from the nuclear fuel cycle.

  11. Sandia National Laboratories Medical Isotope Reactor concept.

    SciTech Connect

    Coats, Richard Lee; Dahl, James J.; Parma, Edward J., Jr.

    2010-04-01

    This report describes the Sandia National Laboratories Medical Isotope Reactor and hot cell facility concepts. The reactor proposed is designed to be capable of producing 100% of the U.S. demand for the medical isotope {sup 99}Mo. The concept is novel in that the fuel for the reactor and the targets for the {sup 99}Mo production are the same. There is no driver core required. The fuel pins that are in the reactor core are processed on a 7 to 21 day irradiation cycle. The fuel is low enriched uranium oxide enriched to less than 20% {sup 235}U. The fuel pins are approximately 1 cm in diameter and 30 to 40 cm in height, clad with Zircaloy (zirconium alloy). Approximately 90 to 150 fuel pins are arranged in the core in a water pool {approx}30 ft deep. The reactor power level is 1 to 2 MW. The reactor concept is a simple design that is passively safe and maintains negative reactivity coefficients. The total radionuclide inventory in the reactor core is minimized since the fuel/target pins are removed and processed after 7 to 21 days. The fuel fabrication, reactor design and operation, and {sup 99}Mo production processing use well-developed technologies that minimize the technological and licensing risks. There are no impediments that prevent this type of reactor, along with its collocated hot cell facility, from being designed, fabricated, and licensed today.

  12. Generic mission planning concepts for space astronomy missions

    NASA Technical Reports Server (NTRS)

    Guffin, O. T.; Onken, J. F.

    1993-01-01

    The past two decades have seen the rapid development of space astronomy, both manned and unmanned, and the concurrent proliferation of the operational concepts and software that have been produced to support each individual project. Having been involved in four of these missions since the '70's and three yet to fly in the present decade, the authors believe it is time to step back and evaluate this body of experience from a macro-systems point of view to determine the potential for generic mission planning concepts that could be applied to future missions. This paper presents an organized evaluation of astronomy mission planning functions, functional flows, iteration cycles, replanning activities, and the requirements that drive individual concepts to specific solutions. The conclusions drawn from this exercise are then used to propose a generic concept that could support multiple missions.

  13. A fission fragment reactor concept for nuclear space propulsion

    NASA Astrophysics Data System (ADS)

    Suo-Anttila, A. J.; Parma, E. J.; Wright, S. A.; Vernon, M. E.; Pickard, P. S.

    1991-10-01

    Sandia National Laboratory (SNL) has proposed a new nuclear thermal propulsion concept that uses fission fragments to directly heat the propellant up to 1000 K or higher above the material temperatures. The concept offers significant advantages over traditional solid core nuclear rocket concepts because of higher propellant exit temperatures while at the same time providing for more reliable operation due to lower structure temperatures and lower power densities. The concept can be operated in either steady state or pulsed modes. The engine consists of tubular modules, each with its own pressure boundary and rocket nozzle. The steady state mode requires a large engine with a reflector for criticality, provides high thrust and high ISP. The pulse mode utilizes a driver reactor for criticality and can be considerably smaller with lower but scaleable thrust. The pulse mode does require an external heat radiator for reactor cooling, which limits its duty cycle.

  14. Reversible Cycling of Silicon and Silicon Alloys

    NASA Astrophysics Data System (ADS)

    Obrovac, Mark

    2012-02-01

    Lithium ion batteries typically use a graphite negative electrode. Silicon can store more lithium than any other element and has long been considered as an attractive replacement for graphite. The theoretical lithium storage capacity of silicon is nearly ten times higher than graphite volumetrically and three times higher gravimetrically. The equilibrium Si-Li binary system is well known. Completely new phase behaviors are observed at room temperature. This includes the formation of a new phase, Li15Si4, which is the highest lithium containing phase at room temperature [1]. The formation of Li15Si4 is accompanied by a 280 percent volume expansion of silicon. During de-alloying this phase contracts, forming amorphous silicon. The volume expansion of alloys can cause intra-particle fracture and inter-particle disconnection; leading to loss of cycle life. To overcome issues with volume expansion requires a detailed knowledge of Li-Si phase behavior, careful design of the composition and nanostructure of the alloy and the microstructure of the negative electrode [2]. In this presentation the phase behavior of the Li-Si system will be described. Using this knowledge alone, strategies can be developed so that silicon can be reversibly cycled in a battery hundreds of times. Further increases in energy density and efficiency can be gained by alloying silicon with other elements, while controlling microstructure [2]. Coupled with negative electrode design strategies, practical negative electrodes for lithium ion cells can be developed based on bulk materials, with significant energy density improvement over conventional electrodes. [4pt] [1] M.N. Obrovac and L.J. Krause, J. Electrochem. Soc., 154 (2007) A103. [0pt] [2] M.N. Obrovac, Leif Christensen, Dinh Ba Le, and J.R. Dahn, J. Electrochem. Soc., 154 (2007) A849

  15. The Saturn management concept

    NASA Technical Reports Server (NTRS)

    Bilstein, R. E.

    1974-01-01

    Management of the Saturn launch vehicles was an evolutionary process, requiring constant interaction between NASA Headquarters, the Marshall Space Flight Center (particularly the Saturn 5 Program Office), and the various prime contractors. Successful Saturn management was a blend of the decades of experience of the von Braun team, management concepts from the Army, Navy, Air Force, and Government, and private industry. The Saturn 5 Program Office shared a unique relationship with the Apollo Program Office at NASA Headquarters. Much of the success of the Saturn 5 Program Office was based on its painstaking attention to detail, emphasis on individual responsibilities (backed up by comprehensive program element plans and management matrices), and a high degree of visibility as embodied in the Program Control Center.

  16. REP Concept Feasibility Study

    NASA Technical Reports Server (NTRS)

    Edwards, Daryl A.; Ensworth, Clinton B. F.; Goodnight, Thomas W.; Sheehe, Charles J.; Wiersma, Stephen C.; Adamsen, Paul B., II; Frank, Larry

    2004-01-01

    Radioisotope Electric Propulsion (REP) may have the potential to provide certain advantages, over conventional chemical propulsion, for outer planetary exploration involving small bodies and long term investigations for medium class missions requiring power comparable to past outer planetary exploration missions. This paper describes a study that investigates the concept s feasibility by performing a preliminary conceptual design of an REP-based spacecraft for a design reference mission. The mission utilizes a spacecraft with a radioisotope power supply less than one kilowatt while operating for a minimum of 10-years. A key element of the REP spacecraft is to ensure sustained science return by orbiting or flying in formation with selected targets. Utilizing current and impending technological advances, this study finds that at a conceptual design level a small body REP orbiter/explorer appears to be feasible for the design reference mission selected for this study.

  17. Bioreactor design concepts

    NASA Technical Reports Server (NTRS)

    Bowie, William

    1987-01-01

    Two parallel lines of work are underway in the bioreactor laboratory. One of the efforts is devoted to the continued development and utilization of a laboratory research system. That system's design is intended to be fluid and dynamic. The sole purpose of such a device is to allow testing and development of equipment concepts and procedures. Some of the results of those processes are discussed. A second effort is designed to produce a flight-like bioreactor contained in a double middeck locker. The result of that effort has been to freeze a particular bioreactor design in order to allow fabrication of the custom parts. The system is expected to be ready for flight in early 1988. However, continued use of the laboratory system will lead to improvements in the space bioreactor. Those improvements can only be integrated after the initial flight series.

  18. Introducing the CTA concept

    NASA Astrophysics Data System (ADS)

    Acharya, B. S.; Actis, M.; Aghajani, T.; Agnetta, G.; Aguilar, J.; Aharonian, F.; Ajello, M.; Akhperjanian, A.; Alcubierre, M.; Aleksić, J.; Alfaro, R.; Aliu, E.; Allafort, A. J.; Allan, D.; Allekotte, I.; Amato, E.; Anderson, J.; Angüner, E. O.; Antonelli, L. A.; Antoranz, P.; Aravantinos, A.; Arlen, T.; Armstrong, T.; Arnaldi, H.; Arrabito, L.; Asano, K.; Ashton, T.; Asorey, H. G.; Awane, Y.; Baba, H.; Babic, A.; Baby, N.; Bähr, J.; Bais, A.; Baixeras, C.; Bajtlik, S.; Balbo, M.; Balis, D.; Balkowski, C.; Bamba, A.; Bandiera, R.; Barber, A.; Barbier, C.; Barceló, M.; Barnacka, A.; Barnstedt, J.; Barres de Almeida, U.; Barrio, J. A.; Basili, A.; Basso, S.; Bastieri, D.; Bauer, C.; Baushev, A.; Becerra, J.; Becherini, Y.; Bechtol, K. C.; Becker Tjus, J.; Beckmann, V.; Bednarek, W.; Behera, B.; Belluso, M.; Benbow, W.; Berdugo, J.; Berger, K.; Bernard, F.; Bernardino, T.; Bernlöhr, K.; Bhat, N.; Bhattacharyya, S.; Bigongiari, C.; Biland, A.; Billotta, S.; Bird, T.; Birsin, E.; Bissaldi, E.; Biteau, J.; Bitossi, M.; Blake, S.; Blanch Bigas, O.; Blasi, P.; Bobkov, A.; Boccone, V.; Boettcher, M.; Bogacz, L.; Bogart, J.; Bogdan, M.; Boisson, C.; Boix Gargallo, J.; Bolmont, J.; Bonanno, G.; Bonardi, A.; Bonev, T.; Bonifacio, P.; Bonnoli, G.; Bordas, P.; Borgland, A.; Borkowski, J.; Bose, R.; Botner, O.; Bottani, A.; Bouchet, L.; Bourgeat, M.; Boutonnet, C.; Bouvier, A.; Brau-Nogué, S.; Braun, I.; Bretz, T.; Briggs, M.; Bringmann, T.; Brook, P.; Brun, P.; Brunetti, L.; Buanes, T.; Buckley, J.; Buehler, R.; Bugaev, V.; Bulgarelli, A.; Bulik, T.; Busetto, G.; Buson, S.; Byrum, K.; Cailles, M.; Cameron, R.; Camprecios, J.; Canestrari, R.; Cantu, S.; Capalbi, M.; Caraveo, P.; Carmona, E.; Carosi, A.; Carr, J.; Carton, P.-H.; Casanova, S.; Casiraghi, M.; Catalano, O.; Cavazzani, S.; Cazaux, S.; Cerruti, M.; Chabanne, E.; Chadwick, P.; Champion, C.; Chen, A.; Chiang, J.; Chiappetti, L.; Chikawa, M.; Chitnis, V. R.; Chollet, F.; Chudoba, J.; Cieślar, M.; Cillis, A.; Cohen-Tanugi, J.; Colafrancesco, S.; Colin, P.; Colome, J.; Colonges, S.; Compin, M.; Conconi, P.; Conforti, V.; Connaughton, V.; Conrad, J.; Contreras, J. L.; Coppi, P.; Corona, P.; Corti, D.; Cortina, J.; Cossio, L.; Costantini, H.; Cotter, G.; Courty, B.; Couturier, S.; Covino, S.; Crimi, G.; Criswell, S. J.; Croston, J.; Cusumano, G.; Dafonseca, M.; Dale, O.; Daniel, M.; Darling, J.; Davids, I.; Dazzi, F.; De Angelis, A.; De Caprio, V.; De Frondat, F.; de Gouveia Dal Pino, E. M.; de la Calle, I.; De La Vega, G. A.; de los Reyes Lopez, R.; De Lotto, B.; De Luca, A.; de Mello Neto, J. R. T.; de Naurois, M.; de Oliveira, Y.; de Oña Wilhelmi, E.; de Souza, V.; Decerprit, G.; Decock, G.; Deil, C.; Delagnes, E.; Deleglise, G.; Delgado, C.; Della Volpe, D.; Demange, P.; Depaola, G.; Dettlaff, A.; Di Paola, A.; Di Pierro, F.; Díaz, C.; Dick, J.; Dickherber, R.; Dickinson, H.; Diez-Blanco, V.; Digel, S.; Dimitrov, D.; Disset, G.; Djannati-Ataï, A.; Doert, M.; Dohmke, M.; Domainko, W.; Dominis Prester, D.; Donat, A.; Dorner, D.; Doro, M.; Dournaux, J.-L.; Drake, G.; Dravins, D.; Drury, L.; Dubois, F.; Dubois, R.; Dubus, G.; Dufour, C.; Dumas, D.; Dumm, J.; Durand, D.; Dyks, J.; Dyrda, M.; Ebr, J.; Edy, E.; Egberts, K.; Eger, P.; Einecke, S.; Eleftheriadis, C.; Elles, S.; Emmanoulopoulos, D.; Engelhaupt, D.; Enomoto, R.; Ernenwein, J.-P.; Errando, M.; Etchegoyen, A.; Evans, P.; Falcone, A.; Fantinel, D.; Farakos, K.; Farnier, C.; Fasola, G.; Favill, B.; Fede, E.; Federici, S.; Fegan, S.; Feinstein, F.; Ferenc, D.; Ferrando, P.; Fesquet, M.; Fiasson, A.; Fillin-Martino, E.; Fink, D.; Finley, C.; Finley, J. P.; Fiorini, M.; Firpo Curcoll, R.; Flores, H.; Florin, D.; Focke, W.; Föhr, C.; Fokitis, E.; Font, L.; Fontaine, G.; Fornasa, M.; Förster, A.; Fortson, L.; Fouque, N.; Franckowiak, A.; Fransson, C.; Fraser, G.; Frei, R.; Albuquerque, I. F. M.; Fresnillo, L.; Fruck, C.; Fujita, Y.; Fukazawa, Y.; Fukui, Y.; Funk, S.; Gäbele, W.; Gabici, S.; Gabriele, R.; Gadola, A.; Galante, N.; Gall, D.; Gallant, Y.; Gámez-García, J.; García, B.; Garcia López, R.; Gardiol, D.; Garrido, D.; Garrido, L.; Gascon, D.; Gaug, M.; Gaweda, J.; Gebremedhin, L.; Geffroy, N.; Gerard, L.; Ghedina, A.; Ghigo, M.; Giannakaki, E.; Gianotti, F.; Giarrusso, S.; Giavitto, G.; Giebels, B.; Gika, V.; Giommi, P.; Girard, N.; Giro, E.; Giuliani, A.; Glanzman, T.; Glicenstein, J.-F.; Godinovic, N.; Golev, V.; Gomez Berisso, M.; Gómez-Ortega, J.; Gonzalez, M. M.; González, A.; González, F.; González Muñoz, A.; Gothe, K. S.; Gougerot, M.; Graciani, R.; Grandi, P.; Grañena, F.; Granot, J.; Grasseau, G.; Gredig, R.; Green, A.; Greenshaw, T.; Grégoire, T.; Grimm, O.; Grube, J.; Grudzinska, M.; Gruev, V.; Grünewald, S.; Grygorczuk, J.; Guarino, V.; Gunji, S.; Gyuk, G.; Hadasch, D.; Hagiwara, R.; Hahn, J.; Hakansson, N.; Hallgren, A.; Hamer Heras, N.; Hara, S.; Hardcastle, M. J.; Harris, J.; Hassan, T.; Hatanaka, K.; Haubold, T.; Haupt, A.; Hayakawa, T.; Hayashida, M.; Heller, R.; Henault, F.; Henri, G.; Hermann, G.; Hermel, R.; Herrero, A.; Hidaka, N.; Hinton, J.; Hoffmann, D.; Hofmann, W.; Hofverberg, P.; Holder, J.; Horns, D.; Horville, D.; Houles, J.; Hrabovsky, M.; Hrupec, D.; Huan, H.; Huber, B.; Huet, J.-M.; Hughes, G.; Humensky, T. B.; Huovelin, J.; Ibarra, A.; Illa, J. M.; Impiombato, D.; Incorvaia, S.; Inoue, S.; Inoue, Y.; Ioka, K.; Ismailova, E.; Jablonski, C.; Jacholkowska, A.; Jamrozy, M.; Janiak, M.; Jean, P.; Jeanney, C.; Jimenez, J. J.; Jogler, T.; Johnson, T.; Journet, L.; Juffroy, C.; Jung, I.; Kaaret, P.; Kabuki, S.; Kagaya, M.; Kakuwa, J.; Kalkuhl, C.; Kankanyan, R.; Karastergiou, A.; Kärcher, K.; Karczewski, M.; Karkar, S.; Kasperek, J.; Kastana, D.; Katagiri, H.; Kataoka, J.; Katarzyński, K.; Katz, U.; Kawanaka, N.; Kellner-Leidel, B.; Kelly, H.; Kendziorra, E.; Khélifi, B.; Kieda, D. B.; Kifune, T.; Kihm, T.; Kishimoto, T.; Kitamoto, K.; Kluźniak, W.; Knapic, C.; Knapp, J.; Knödlseder, J.; Köck, F.; Kocot, J.; Kodani, K.; Köhne, J.-H.; Kohri, K.; Kokkotas, K.; Kolitzus, D.; Komin, N.; Kominis, I.; Konno, Y.; Köppel, H.; Korohoda, P.; Kosack, K.; Koss, G.; Kossakowski, R.; Kostka, P.; Koul, R.; Kowal, G.; Koyama, S.; Kozioł, J.; Krähenbühl, T.; Krause, J.; Krawzcynski, H.; Krennrich, F.; Krepps, A.; Kretzschmann, A.; Krobot, R.; Krueger, P.; Kubo, H.; Kudryavtsev, V. A.; Kushida, J.; Kuznetsov, A.; La Barbera, A.; La Palombara, N.; La Parola, V.; La Rosa, G.; Lacombe, K.; Lamanna, G.; Lande, J.; Languignon, D.; Lapington, J.; Laporte, P.; Lavalley, C.; Le Flour, T.; Le Padellec, A.; Lee, S.-H.; Lee, W. H.; Leigui de Oliveira, M. A.; Lelas, D.; Lenain, J.-P.; Leopold, D. J.; Lerch, T.; Lessio, L.; Lieunard, B.; Lindfors, E.; Liolios, A.; Lipniacka, A.; Lockart, H.; Lohse, T.; Lombardi, S.; Lopatin, A.; Lopez, M.; López-Coto, R.; López-Oramas, A.; Lorca, A.; Lorenz, E.; Lubinski, P.; Lucarelli, F.; Lüdecke, H.; Ludwin, J.; Luque-Escamilla, P. L.; Lustermann, W.; Luz, O.; Lyard, E.; Maccarone, M. C.; Maccarone, T. J.; Madejski, G. M.; Madhavan, A.; Mahabir, M.; Maier, G.; Majumdar, P.; Malaguti, G.; Maltezos, S.; Manalaysay, A.; Mancilla, A.; Mandat, D.; Maneva, G.; Mangano, A.; Manigot, P.; Mannheim, K.; Manthos, I.; Maragos, N.; Marcowith, A.; Mariotti, M.; Marisaldi, M.; Markoff, S.; Marszałek, A.; Martens, C.; Martí, J.; Martin, J.-M.; Martin, P.; Martínez, G.; Martínez, F.; Martínez, M.; Masserot, A.; Mastichiadis, A.; Mathieu, A.; Matsumoto, H.; Mattana, F.; Mattiazzo, S.; Maurin, G.; Maxfield, S.; Maya, J.; Mazin, D.; Mc Comb, L.; McCubbin, N.; McHardy, I.; McKay, R.; Medina, C.; Melioli, C.; Melkumyan, D.; Mereghetti, S.; Mertsch, P.; Meucci, M.; Michałowski, J.; Micolon, P.; Mihailidis, A.; Mineo, T.; Minuti, M.; Mirabal, N.; Mirabel, F.; Miranda, J. M.; Mirzoyan, R.; Mizuno, T.; Moal, B.; Moderski, R.; Mognet, I.; Molinari, E.; Molinaro, M.; Montaruli, T.; Monteiro, I.; Moore, P.; Moralejo Olaizola, A.; Mordalska, M.; Morello, C.; Mori, K.; Mottez, F.; Moudden, Y.; Moulin, E.; Mrusek, I.; Mukherjee, R.; Munar-Adrover, P.; Muraishi, H.; Murase, K.; Murphy, A.; Nagataki, S.; Naito, T.; Nakajima, D.; Nakamori, T.; Nakayama, K.; Naumann, C.; Naumann, D.; Naumann-Godo, M.; Nayman, P.; Nedbal, D.; Neise, D.; Nellen, L.; Neustroev, V.; Neyroud, N.; Nicastro, L.; Nicolau-Kukliński, J.; Niedźwiecki, A.; Niemiec, J.; Nieto, D.; Nikolaidis, A.; Nishijima, K.; Nolan, S.; Northrop, R.; Nosek, D.; Nowak, N.; Nozato, A.; O'Brien, P.; Ohira, Y.; Ohishi, M.; Ohm, S.; Ohoka, H.; Okuda, T.; Okumura, A.; Olive, J.-F.; Ong, R. A.; Orito, R.; Orr, M.; Osborne, J.; Ostrowski, M.; Otero, L. A.; Otte, N.; Ovcharov, E.; Oya, I.; Ozieblo, A.; Padilla, L.; Paiano, S.; Paillot, D.; Paizis, A.; Palanque, S.; Palatka, M.; Pallota, J.; Panagiotidis, K.; Panazol, J.-L.; Paneque, D.; Panter, M.; Paoletti, R.; Papayannis, A.; Papyan, G.; Paredes, J. M.; Pareschi, G.; Parks, G.; Parraud, J.-M.; Parsons, D.; Paz Arribas, M.; Pech, M.; Pedaletti, G.; Pelassa, V.; Pelat, D.; Perez, M. d. C.; Persic, M.; Petrucci, P.-O.; Peyaud, B.; Pichel, A.; Pita, S.; Pizzolato, F.; Platos, Ł.; Platzer, R.; Pogosyan, L.; Pohl, M.; Pojmanski, G.; Ponz, J. D.; Potter, W.; Poutanen, J.; Prandini, E.; Prast, J.; Preece, R.; Profeti, F.; Prokoph, H.; Prouza, M.; Proyetti, M.; Puerto-Gimenez, I.; Pühlhofer, G.; Puljak, I.; Punch, M.; Pyzioł, R.; Quel, E. J.; Quinn, J.; Quirrenbach, A.; Racero, E.; Rajda, P. J.; Ramon, P.; Rando, R.; Rannot, R. C.; Rataj, M.; Raue, M.; Reardon, P.; Reimann, O.; Reimer, A.; Reimer, O.; Reitberger, K.; Renaud, M.; Renner, S.; Reville, B.; Rhode, W.; Ribó, M.; Ribordy, M.; Richer, M. G.; Rico, J.; Ridky, J.; Rieger, F.; Ringegni, P.; Ripken, J.; Ristori, P. R.; Riviére, A.; Rivoire, S.; Rob, L.; Roeser, U.; Rohlfs, R.; Rojas, G.; Romano, P.; Romaszkan, W.; Romero, G. E.; Rosen, S.; Rosier Lees, S.; Ross, D.; Rouaix, G.; Rousselle, J.; Rousselle, S.; Rovero, A. C.; Roy, F.; Royer, S.; Rudak, B.; Rulten, C.; Rupiński, M.; Russo, F.; Ryde, F.; Sacco, B.; Saemann, E. O.; Saggion, A.; Sahakian, V.; Saito, K.; Saito, T.; Saito, Y.; Sakaki, N.; Sakonaka, R.; Salini, A.; Sanchez, F.; Sanchez-Conde, M.; Sandoval, A.; Sandaker, H.; Sant'Ambrogio, E.; Santangelo, A.; Santos, E. M.; Sanuy, A.; Sapozhnikov, L.; Sarkar, S.; Sartore, N.; Sasaki, H.; Satalecka, K.; Sawada, M.; Scalzotto, V.; Scapin, V.; Scarcioffolo, M.; Schafer, J.; Schanz, T.; Schlenstedt, S.; Schlickeiser, R.; Schmidt, T.; Schmoll, J.; Schovanek, P.; Schroedter, M.; Schultz, C.; Schultze, J.; Schulz, A.; Schure, K.; Schwab, T.; Schwanke, U.; Schwarz, J.; Schwarzburg, S.; Schweizer, T.; Schwemmer, S.; Segreto, A.; Seiradakis, J.-H.; Sembroski, G. H.; Seweryn, K.; Sharma, M.; Shayduk, M.; Shellard, R. C.; Shi, J.; Shibata, T.; Shibuya, A.; Shum, E.; Sidoli, L.; Sidz, M.; Sieiro, J.; Sikora, M.; Silk, J.; Sillanpää, A.; Singh, B. B.; Sitarek, J.; Skole, C.; Smareglia, R.; Smith, A.; Smith, D.; Smith, J.; Smith, N.; Sobczyńska, D.; Sol, H.; Sottile, G.; Sowiński, M.; Spanier, F.; Spiga, D.; Spyrou, S.; Stamatescu, V.; Stamerra, A.; Starling, R.; Stawarz, Ł.; Steenkamp, R.; Stegmann, C.; Steiner, S.; Stergioulas, N.; Sternberger, R.; Sterzel, M.; Stinzing, F.; Stodulski, M.; Straumann, U.; Strazzeri, E.; Stringhetti, L.; Suarez, A.; Suchenek, M.; Sugawara, R.; Sulanke, K.-H.; Sun, S.; Supanitsky, A. D.; Suric, T.; Sutcliffe, P.; Sykes, J.; Szanecki, M.; Szepieniec, T.; Szostek, A.; Tagliaferri, G.; Tajima, H.; Takahashi, H.; Takahashi, K.; Takalo, L.; Takami, H.; Talbot, G.; Tammi, J.; Tanaka, M.; Tanaka, S.; Tasan, J.; Tavani, M.; Tavernet, J.-P.; Tejedor, L. A.; Telezhinsky, I.; Temnikov, P.; Tenzer, C.; Terada, Y.; Terrier, R.; Teshima, M.; Testa, V.; Tezier, D.; Thuermann, D.; Tibaldo, L.; Tibolla, O.; Tiengo, A.; Tluczykont, M.; Todero Peixoto, C. J.; Tokanai, F.; Tokarz, M.; Toma, K.; Torii, K.; Tornikoski, M.; Torres, D. F.; Torres, M.; Tosti, G.; Totani, T.; Toussenel, F.; Tovmassian, G.; Travnicek, P.; Trifoglio, M.; Troyano, I.; Tsinganos, K.; Ueno, H.; Umehara, K.; Upadhya, S. S.; Usher, T.; Uslenghi, M.; Valdes-Galicia, J. F.; Vallania, P.; Vallejo, G.; van Driel, W.; van Eldik, C.; Vandenbrouke, J.; Vanderwalt, J.; Vankov, H.; Vasileiadis, G.; Vassiliev, V.; Veberic, D.; Vegas, I.; Vercellone, S.; Vergani, S.; Veyssiére, C.; Vialle, J. P.; Viana, A.; Videla, M.; Vincent, P.; Vincent, S.; Vink, J.; Vlahakis, N.; Vlahos, L.; Vogler, P.; Vollhardt, A.; von Gunten, H.-P.; Vorobiov, S.; Vuerli, C.; Waegebaert, V.; Wagner, R.; Wagner, R. G.; Wagner, S.; Wakely, S. P.; Walter, R.; Walther, T.; Warda, K.; Warwick, R.; Wawer, P.; Wawrzaszek, R.; Webb, N.; Wegner, P.; Weinstein, A.; Weitzel, Q.; Welsing, R.; Werner, M.; Wetteskind, H.; White, R.; Wierzcholska, A.; Wiesand, S.; Wilkinson, M.; Williams, D. A.; Willingale, R.; Winiarski, K.; Wischnewski, R.; Wiśniewski, Ł.; Wood, M.; Wörnlein, A.; Xiong, Q.; Yadav, K. K.; Yamamoto, H.; Yamamoto, T.; Yamazaki, R.; Yanagita, S.; Yebras, J. M.; Yelos, D.; Yoshida, A.; Yoshida, T.; Yoshikoshi, T.; Zabalza, V.; Zacharias, M.; Zajczyk, A.; Zanin, R.; Zdziarski, A.; Zech, A.; Zhao, A.; Zhou, X.; Ziętara, K.; Ziolkowski, J.; Ziółkowski, P.; Zitelli, V.; Zurbach, C.; Żychowski, P.; CTA Consortium

    2013-03-01

    The Cherenkov Telescope Array (CTA) is a new observatory for very high-energy (VHE) gamma rays. CTA has ambitions science goals, for which it is necessary to achieve full-sky coverage, to improve the sensitivity by about an order of magnitude, to span about four decades of energy, from a few tens of GeV to above 100 TeV with enhanced angular and energy resolutions over existing VHE gamma-ray observatories. An international collaboration has formed with more than 1000 members from 27 countries in Europe, Asia, Africa and North and South America. In 2010 the CTA Consortium completed a Design Study and started a three-year Preparatory Phase which leads to production readiness of CTA in 2014. In this paper we introduce the science goals and the concept of CTA, and provide an overview of the project.

  19. [Charcot's epistemological concept].

    PubMed

    Lellouch, A

    1994-01-01

    Through a brilliant medical way, Charcot was, at the same time, rheumatologist, geriatric, clinician, pathologist - and mainly neuro-pathologist - ending as a psychiatrist (according to todays medical terminology). Here, we will point out how much scientific theory and philosophy may support an original concept very unusual during the second half of XIXth century medicine. Describing connection between biology and medicine according to Auguste Comte thoughte, the author is thoroughly going into the course introduced by Charcot: scientific medicine instead of empirical one; structural medical-anatomy against rudimentary approach and rising of experimental medicine; impact of human sciences on medical knowledge; appearance of specialists near general practitioners; idea of organic disturbances denying any 'faith healing". In fact, Charcot asserts that bedside instruction prevails against accurate sciences. PMID:11640482

  20. Advanced Sensor Concepts

    NASA Technical Reports Server (NTRS)

    Alhorn, D. C.; Howard, D. E.; Smith, D. A.

    2005-01-01

    The Advanced Sensor Concepts project was conducted under the Center Director's Discretionary Fund at the Marshall Space Flight Center. Its objective was to advance the technology originally developed for the Glovebox Integrated Microgravity Isolation Technology project. The objective of this effort was to develop and test several new motion sensors. To date, the investigators have invented seven new technologies during this endeavor and have conceived several others. The innovative basic sensor technology is an absolute position sensor. It employs only two active components, and it is simple, inexpensive, reliable, repeatable, lightweight, and relatively unobtrusive. Two sensors can be utilized in the same physical space to achieve redundancy. The sensor has micrometer positional accuracy and can be configured as a two- or three-dimensional sensor. The sensor technology has the potential to pioneer a new class of linear and rotary sensors. This sensor is the enabling technology for autonomous assembly of modular structures in space and on extraterrestrial locations.