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Sample records for ebr-ii inherent safety

  1. Benchmark Simulations of the Thermal-Hydraulic Responses during EBR-II Inherent Safety Tests using SAM

    SciTech Connect

    Hu, Rui; Sumner, Tyler S.

    2016-01-01

    An advanced system analysis tool SAM is being developed for fast-running, improved-fidelity, and wholeplant transient analyses at Argonne National Laboratory under DOE-NE’s Nuclear Energy Advanced Modeling and Simulation (NEAMS) program. As an important part of code development, companion validation activities are being conducted to ensure the performance and validity of the SAM code. This paper presents the benchmark simulations of two EBR-II tests, SHRT-45R and BOP- 302R, whose data are available through the support of DOE-NE’s Advanced Reactor Technology (ART) program. The code predictions of major primary coolant system parameter are compared with the test results. Additionally, the SAS4A/SASSYS-1 code simulation results are also included for a code-to-code comparison.

  2. Reliability and extended-life potential of EBR-II

    SciTech Connect

    King, R W

    1985-01-01

    Although the longlife potential of liquid-metal-cooled reactors (LMRs) has been only partially demonstrated, many factors point to the potential for exceptionally long life. EBR-II has the opportunity to become the first LMR to achieve an operational lifetime of 30 years or more. In 1984 a study of the extended-life potential of EBR-II identified the factors that contribute to the continued successful operation of EBR-II as a power reactor and experimental facility. Also identified were factors that could cause disruptions in the useful life of the facility. Although no factors were found that would inherently limit the life of EBR-II, measures were identified that could help ensure continued plant availability. These measures include the implementation of more effective surveillance, diagnostic, and control systems to complement the inherent safety and reliability features of EBR-II. An operating lifetime of well beyond 30 years is certainly feasible.

  3. Benchmark specifications for EBR-II shutdown heat removal tests

    SciTech Connect

    Sofu, T.; Briggs, L. L.

    2012-07-01

    Argonne National Laboratory (ANL) is hosting an IAEA-coordinated research project on benchmark analyses of sodium-cooled fast reactor passive safety tests performed at the Experimental Breeder Reactor-II (EBR-II). The benchmark project involves analysis of a protected and an unprotected loss of flow tests conducted during an extensive testing program within the framework of the U.S. Integral Fast Reactor program to demonstrate the inherently safety features of EBR-II as a pool-type, sodium-cooled fast reactor prototype. The project is intended to improve the participants' design and safety analysis capabilities for sodium-cooled fast reactors through validation and qualification of safety analysis codes and methods. This paper provides a description of the EBR-II tests included in the program, and outlines the benchmark specifications being prepared to support the IAEA-coordinated research project. (authors)

  4. Criticality safety requirements for transporting EBR-II fuel bottles stored at INTEC

    SciTech Connect

    Lell, R. M.; Pope, C. L.

    2000-03-14

    Two carrier/shipping cask options are being developed to transport bottles of EBR-II fuel elements stored at INTEC. Some fuel bottles are intact, but some have developed leaks. Reactivity control requirements to maintain subcriticality during the hypothetical transport accident have been examined for both transport options for intact and leaking bottles. Poison rods, poison sleeves, and dummy filler bottles were considered; several possible poison materials and several possible dummy filler materials were studied. The minimum number of poison rods or dummy filler bottles has been determined for each carrier for transport of intact and leaking bottles.

  5. Embedded computer systems for control applications in EBR-II

    SciTech Connect

    Carlson, R.B.; Start, S.E.

    1993-03-01

    The purpose of this paper is to describe the embedded computer systems approach taken at Experimental Breeder Reactor II (EBR-II) for non-safety related systems. The hardware and software structures for typical embedded systems are presented The embedded systems development process is described. Three examples are given which illustrate typical embedded computer applications in EBR-II.

  6. Embedded computer systems for control applications in EBR-II

    SciTech Connect

    Carlson, R.B.; Start, S.E.

    1993-01-01

    The purpose of this paper is to describe the embedded computer systems approach taken at Experimental Breeder Reactor II (EBR-II) for non-safety related systems. The hardware and software structures for typical embedded systems are presented The embedded systems development process is described. Three examples are given which illustrate typical embedded computer applications in EBR-II.

  7. EBR-II Data Digitization

    SciTech Connect

    Yoon, Su-Jong; Rabiti, Cristian; Sackett, John

    2014-08-01

    1. Objectives To produce a validation database out of those recorded signals it will be necessary also to identify the documents need to reconstruct the status of reactor at the time of the beginning of the recordings. This should comprehends the core loading specification (assemblies type and location and burn-up) along with this data the assemblies drawings and the core drawings will be identified. The first task of the project will be identify the location of the sensors, with respect the reactor plant layout, and the physical quantities recorded by the Experimental Breeder Reactor-II (EBR-II) data acquisition system. This first task will allow guiding and prioritizing the selection of drawings needed to numerically reproduce those signals. 1.1 Scopes and Deliverables The deliverables of this project are the list of sensors in EBR-II system, the identification of storing location of those sensors, identification of a core isotopic composition at the moment of the start of system recording. Information of the sensors in EBR-II reactor system was summarized from the EBR-II system design descriptions listed in Section 1.2.

  8. Deactivation of the EBR-II complex

    SciTech Connect

    Michelbacher, J.A.; Earle, O.K.; Henslee, S.P.

    1997-12-31

    In January of 1994, the Department of Energy mandated the termination of the Integral Fast Reactor (IFR) Program, effective October 1, 1994. To comply with this decision, Argonne National Laboratory-West (ANL-W) prepared a plan providing detailed requirements to place the Experimental Breeder Reactor-II (EBR-II) in a radiologically and industrially safe condition, including removal of all irradiated fuel assemblies from the reactor plant, and removal and stabilization of the primary and secondary sodium, a liquid metal used to transfer heat within the reactor plant. The ultimate goal of the deactivation process is to place the EBR-II complex in a stable condition until a decontamination and decommissioning (D&D) plan can be prepared, thereby minimizing requirements for maintenance and surveillance and maximizing the amount of time for radioactive decay. The final closure state will be achieved in full compliance with federal, state and local environmental, safety, and health regulations and requirements. The decision to delay the development of a detailed D&D plan has necessitated this current action. The EBR-II is a pool-type reactor. The primary system contains approximately 87,000 gallons of sodium, while the secondary system has 13,000 gallons. In order to properly dispose of the sodium in compliance with the Resource Conservation and Recovery Act (RCRA), a facility has been built to react the sodium to a dry carbonate powder in a two stage process. Deactivation of a liquid metal fast breeder reactor (LMFBR) presents unique concerns. Residual amounts of sodium remaining in the primary and secondary systems must be either reacted or inerted to preclude future concerns with sodium-air reactions that generate explosive mixtures of hydrogen and leave corrosive compounds. Residual amounts of sodium on components will effectively {open_quotes}solder{close_quotes} components in place, making future operation or removal unfeasible.

  9. A transient overpower experiment in EBR-II

    SciTech Connect

    Herzog, J.P.; Tsai, H.; Dean, E.M.; Aoyama, T.; Yamamoto, K.

    1994-03-01

    The TOPI-IE test was a transient overpower test on irradiate mixed-oxide fuel pins in the Experimental Breeder Reactor-II (EBR-II). The test, the fifth in a series, was part of a cooperative program between the US Department of Energy and the Power Reactor and Nuclear Fuel Development Corporation of Japan to conduct operational transient testing on mixed-oxide fuel pins in the metal-fueled EBR-II. The principle objective of the TOPI-1E test was to assess breaching margins for irradiated mixed-oxide fuel pins over the Plant Protection System (PPS) thresholds during a slow, extended overpower transient. This paper describes the effect of the TOPI-1E experiment on reactor components and the impact of the experiment on the long-term operability of the reactor. The paper discusses the role that SASSYS played in the pre-test safety analysis of the experiment. The ability of SASSYS to model transient overpower events is detailed by comparisons of data from the experiment with computed reactor variables from a SASSYS post-test simulation of the experiment.

  10. EBR-II and TREAT Digitization Project

    SciTech Connect

    Griffith, George W.; Rabiti, Cristian

    2015-09-01

    Digitizing the technical drawings for EBR-II and TREAT provides multiple benefits. Moving the scanned or hard copy drawings to modern 3-D CAD (Computer Aided Drawing) format saves data that could be lost over time. The 3-D drawings produce models that can interface with other drawings to make complex assemblies. The 3-D CAD format can also include detailed material properties and parametric coding that can tie critical dimensions together allowing easier modification. Creating the new files from the old drawings has found multiple inconsistencies that are being flagged or corrected improving understanding of the reactor(s).

  11. EBR-II: twenty years of operating experience

    SciTech Connect

    Lentz, G.L.; Buschman, H.W.; Smith, R.N.

    1985-01-01

    Experimental Breeder Reactor No. 2 (EBR-II) is an unmoderated, sodium-cooled reactor with a design power of 62.5 MWt. For the last 20 years EBR-II has operated safely, has demonstrated stable operating characteristics, has shown excellent performance of its sodium components, and has had an excellent plant factor. These years of operating experience provide a valuable resource to the nuclear community for the development and design of future liquid metal fast reactors. This report provides a brief description of the EBR-II plant and its early operating experience, describes some recent problems of interest to the nuclear community, and also mentions some of the significant operating achievements of EBR-II. Finally, a few words and speculations on EBR-II's future are offered. 4 figs., 1 tab.

  12. Seventeen years of LMFBR experience: Experimental Breeder Reactor II (EBR-II)

    SciTech Connect

    Perry, W.H.; Lentz, G.L.; Richardson, W.J.; Wolz, G.C.

    1982-05-01

    Operating experience at EBR-II over the past 17 years has shown that a sodium-cooled pool-type reactor can be safely and efficiently operated and maintained. The reactor has performed predictably and benignly during normal operation and during both unplanned and planned plant upsets. The duplex-tube evaporators and superheaters have never experienced a sodium/water leak, and the rest of the steam-generating system has operated without incident. There has been no noticeable degradation of the heat transfer efficiency of the evaporators and superheaters, except for the one superheater replaced in 1981. There has been no need to perform any chemical cleaning of steam-system components. Operation of EBR-II has produced a wealth of information. As an irradiation facility, EBR-II has generated specific information on the behavior of oxide, carbide, and metallic fuels. As an LMFBR power plant, EBR-II has produced general information related to plant-systems and equipment design, plant safety, plant availability, and plant maintenance.

  13. Fault tree analysis of the EBR-II reactor shutdown system

    SciTech Connect

    Kamal, S.A.; Hill, D.J.

    1992-01-01

    As part of the level I Probabilistic Risk Assessment of the Experimental Breeder Reactor II (EBR-II), detailed fault trees for the reactor shutdown system are developed. Fault tree analysis is performed for two classes of transient events that are of particular importance to EBR-II operation: loss-of-flow and transient-overpower. In all parts of EBR-II reactor shutdown system, redundancy has been utilized in order to reduce scram failure probability. Therefore, heavy emphasis is placed in the fault trees on the common cause failures (CCFs) among similar mechanical components of the control and safety rods and among similar electrical components in redundant detection channels and shutdown strings. Generic beta-factors that cover all types of similar components and reflect redundancy level are used to model the CCFs. Human errors are addressed in the fault trees in two major areas: errors that would prevent the automatic scram channels from detecting the abnormal events and errors that would prevent utilization of the manual scram capability. The fault tree analysis of the EBR-II shutdown system has provided not only a systematic process for calculating the probabilities of system failures but also useful insights into the system and how its elements interact during transient events that require shutdown.

  14. Fault tree analysis of the EBR-II reactor shutdown system

    SciTech Connect

    Kamal, S.A.; Hill, D.J.

    1992-12-01

    As part of the level I Probabilistic Risk Assessment of the Experimental Breeder Reactor II (EBR-II), detailed fault trees for the reactor shutdown system are developed. Fault tree analysis is performed for two classes of transient events that are of particular importance to EBR-II operation: loss-of-flow and transient-overpower. In all parts of EBR-II reactor shutdown system, redundancy has been utilized in order to reduce scram failure probability. Therefore, heavy emphasis is placed in the fault trees on the common cause failures (CCFs) among similar mechanical components of the control and safety rods and among similar electrical components in redundant detection channels and shutdown strings. Generic beta-factors that cover all types of similar components and reflect redundancy level are used to model the CCFs. Human errors are addressed in the fault trees in two major areas: errors that would prevent the automatic scram channels from detecting the abnormal events and errors that would prevent utilization of the manual scram capability. The fault tree analysis of the EBR-II shutdown system has provided not only a systematic process for calculating the probabilities of system failures but also useful insights into the system and how its elements interact during transient events that require shutdown.

  15. Experimental Breeder Reactor II (EBR-II): Instrumentation for core surveillance

    SciTech Connect

    Christensen, L.J.

    1989-01-01

    EBR-II has operated for 25 years in support of several major programs. During this time period, several of the original, non-replaceable, flow sensors, RDT sensors and thermocouples have failed in the primary system. This has led to the development of new sensors and the use of calculated values using computer models of the plant. It is important for the next generation of LMR reactors to minimize or eliminate the use of non-replaceable sensors. EBR-II is perhaps the best modeled reactor in the world, thanks to a dedicated T-H analysis program. The success of this program relied on excellent measurements of temperature and flow in subassemblies in the core. The instrumented subassemblies of the XX series provided that measurement capability. From this test series, EBR-II calculations showed that the core could withstand a loss-of-flow without scram accident and a loss-of-heat sink without scram accident from full reactor power without core damage. From this, reactor designers can now design with confidence, inherently safe reactors. 11 refs., 8 figs.

  16. EBR-II transient operation and test capabilities

    SciTech Connect

    Seidel, B.R.; Cutforth, D.C.; Lentz, G.L.; Lambert, J.D.B.

    1983-01-01

    Experimental fuel pins intended for eventual use in LMFBR's have been irradiated for many years in fast test reactors. A wealth of data have been obtained on their performance under steady-state conditions, and fuel-pin performance codes have been developed to predict their behavior. In parallel, safety tests of fuel pins to explore behavior under accident conditions have been performed in transient reactors like TREAT in the US, and CABRI in France. These two types of testing generally have had different aims and have tended to produce results which are not reconcilable with a common modeling code, such as a LIFE or COMETHE, in the middle ground between normal and off-normal conditions. But as the licensing and commercialization of LMFBR's approaches, the attention and needs of the fuel-pin designer and licenser have focused on this middle ground between steady-state and accident testing of fuel pins and subassemblies. Preparations and now capability for operational reliability testing at EBR-II have been the subject of papers at recent conferences. This paper updates the status of those preparations to the present time when the ORT program is about to begin.

  17. The COBRA-1B irradiation experiment in EBR-II

    SciTech Connect

    Tsai, H.; Hins, A.G.; Strain, R.V.; Smith, D.L.

    1994-09-01

    The objective of the forthcoming COBRA-1B experiment in EBR-II is to evaluate the effects of fast neutron irradiation on the physical and mechanical properties of candidate fusion structural materials. Of special interest in this experiment will be ITER-relevant temperature and exposure for the test specimens. Approximately 50% of the irradiation test volume will be devoted to vanadium-alloy specimens. Design of the COBRA-1B irradiation experiment began in this reporting period and is in progress. The target reactor insertion date for COBRA-1B is September 1994. Technical and programmatic feasibility approval for the experiment has been granted by EBR-II Operations.

  18. The EBR-II Probabilistic Risk Assessment: Results and insights

    SciTech Connect

    Hill, D.J.; Ragland, W.A.; Roglans, J.

    1993-12-31

    This paper summarizes the results from the recently completed EBR-II Probabilistic Risk Assessment (PRA) and provides an analysis of the source of risk of the operation of EBR-II from both internal and external initiating events. The EBR-II PRA explicitly accounts for the role of reactivity feedbacks in reducing fuel damage. The results show that the expected core damage frequency from internal initiating events at EBR-II is very low, 1. 6 10{sup {minus}6} yr{sup {minus}1}, even with a wide definition of core damage (essentially that of exceeding Technical Specification limits). The probability of damage, primarily due to liquid metal fires, from externally initiated events (excluding earthquake) is 3.6 10{sup {minus}6} yr{sup {minus}1}. overall these results are considerably better than results for other research reactors and the nuclear industry in general and stem from three main sources: low likelihood of loss of coolant due to low system pressure and top entry double, vessels; low likelihood of loss of decay heat removal due to reliance on passive means; and low likelihood of power/flow mismatch due to both passive feedbacks and reliability of rod scram capability.

  19. The EBR-II Probabilistic Risk Assessment: Results and insights

    SciTech Connect

    Hill, D.J.; Ragland, W.A.; Roglans, J.

    1993-01-01

    This paper summarizes the results from the recently completed EBR-II Probabilistic Risk Assessment (PRA) and provides an analysis of the source of risk of the operation of EBR-II from both internal and external initiating events. The EBR-II PRA explicitly accounts for the role of reactivity feedbacks in reducing fuel damage. The results show that the expected core damage frequency from internal initiating events at EBR-II is very low, 1. 6 10[sup [minus]6] yr[sup [minus]1], even with a wide definition of core damage (essentially that of exceeding Technical Specification limits). The probability of damage, primarily due to liquid metal fires, from externally initiated events (excluding earthquake) is 3.6 10[sup [minus]6] yr[sup [minus]1]. overall these results are considerably better than results for other research reactors and the nuclear industry in general and stem from three main sources: low likelihood of loss of coolant due to low system pressure and top entry double, vessels; low likelihood of loss of decay heat removal due to reliance on passive means; and low likelihood of power/flow mismatch due to both passive feedbacks and reliability of rod scram capability.

  20. Recent operating experiences and programs at EBR-II

    SciTech Connect

    Lentz, G.L.

    1984-01-01

    Experimental Breeder Reactor No. II (EBR-II) is a pool-type, unmoderated, sodium-cooled reactor with a design power of 62.5 MWt and an electrical generation capability of 20 MW. It has been operated by Argonne National Laboratory for the US government for almost 20 years. During that time, it has operated safely and has demonstrated stable operating characteristics, high availability, and excellent performance of its sodium components. The 20 years of operating experience of EBR-II is a valuable resource to the nuclear community for the development and design of future LMFBR's. Since past operating experience has been extensively reported, this report will focus on recent programs and events.

  1. System modelling to support accelerated fuel transfer rate at EBR-II

    SciTech Connect

    Imel, G.R.; Houshyar, A.; Planchon, H.P.; Cutforth, D.C.

    1995-06-01

    The Experimental Breeder Reactor-II (EBR-II) ia a 62.5 MW(th) liquid metal reactor operated by Argonne National Laboratory for The United States Department of Energy. The reactor is located near Idaho Falls, Idaho at the Argonne-West site (ANL-W). Full power operation was achieved in 1964,- the reactor operated continuously since that time until October 1994 in a variety of configurations depending on the programmatic mission. A three year program was initiated in October, 1993 to replace the 330 depleted uranium blanket subassemblies (S/As) with stainless steel reflectors. It was intended to operate the reactor during the three year blanket unloading program, followed by about a half year of driver fuel unloading. However, in the summer of 1994, Congress dictacted that EBR-II be shut down October 1, and complete defueling without operation. To assist in the planning for resources needed for this defueling campaign, a mathematical model of the fuel handling sequence was developed utilizing the appropriate reliability factors and inherent mm constraints of each stage of the process. The model allows predictions of transfer rates under different scenarios. Additionally, it has facilitated planning of maintenance activities, as well as optimization of resources regarding manpower and modification effort. The model and its application is described in this paper.

  2. Use of a steam leak simulator in EBR-II

    SciTech Connect

    McKee, J.M.; Osterhout, M.M. Batten, R.L.

    1984-01-01

    A steam leak simulator has been installed on EBR-II to periodically test and calibrate the steam-generator leak detection system. Measured amounts of molten anhydrous sodium hydroxide are injected at controlled rates simulating leaks in the range of 0.024 to 0.16 g H/sub 2/O/s. Experience with 11 injections over an 18 month period is described.

  3. An integrated plant-life extension program for EBR-II (Experimental Breeder Reactor)

    SciTech Connect

    King, R.W.

    1986-01-01

    An integrated plant-life extension program is being developed and implemented at EBR-II. The program plan has five primary areas of focus, and is structured to take advantage of inherent features of the liquid-metal-cooled reactor that give it potential for very long life. The program is centered around development and increased use of computer-based software systems for surveillance, diagnostics, prognostics, data handling, and knowledge transfer. Even though the program is only partially implemented, benefits are already being realized in the form of increased understanding of plant system status and performance due to development of diagnostic data-handling software for manipulation of plant sensor data, and improved force monitoring and protection of the remotely operated fuel handling system. The eventual integration of the elements of the program is a key feature that is expected to enhance the overall effectiveness of the program.

  4. Metallic fuels: The EBR-II legacy and recent advances

    SciTech Connect

    Douglas L. Porter; Steven L. Hayes; J. Rory Kennedy

    2012-09-01

    Experimental Breeder Reactor – II (EBR-II) metallic fuel was qualified for high burnup to approximately 10 atomic per cent. Subsequently, the electrometallurgical treatment of this fuel was demonstrated. Advanced metallic fuels are now investigated for increased performance, including ultra-high burnup and actinide burning. Advances include additives to mitigate the fuel/cladding chemical interaction and uranium alloys that combine Mo, Ti and Zr to improve alloy performance. The impacts of the advances—on fabrication, waste streams, electrorefining, etc.—are found to be minimal and beneficial. Owing to extensive research literature and computational methods, only a modest effort is required to complete their development.

  5. Degradation of EBR-II driver fuel during wet storage

    SciTech Connect

    Pahl, R. G.

    2000-03-09

    Characterization data are reported for sodium bonded EBR-II reactor fuel which had been stored underwater in containers since the 1981--1982 timeframe. Ten stainless steel storage containers, which had leaked water during storage due to improper sealing, were retrieved from the ICPP-603 storage basin at the Idaho National Engineering and Environmental Laboratory (INEEL) in Idaho. In the container chosen for detailed destructive analysis, the stainless steel cladding on the uranium alloy fuel had ruptured and fuel oxide sludge filled the bottom of the container. Headspace gas sampling determined that greater than 99% hydrogen was present. Cesium 137, which had leached out of the fuel during the aqueous corrosion process, dominated the radionuclide source term of the water. The metallic sodium from the fuel element bond had reacted with the water, forming a concentrated caustic solution of NaOH.

  6. EBR-II Primary Tank Wash-Water Alternatives Evaluation

    SciTech Connect

    Demmer, R. L.; Heintzelman, J. B.; Merservey, R. H.; Squires, L. N.

    2008-05-01

    The EBR-II reactor at Idaho National Laboratory was a liquid sodium metal cooled reactor that operated for 30 years. It was shut down in 1994; the fuel was removed by 1996; and the bulk of sodium metal coolant was removed from the reactor by 2001. Approximately 1100 kg of residual sodium remained in the primary system after draining the bulk sodium. To stabilize the remaining sodium, both the primary and secondary systems were treated with a purge of moist carbon dioxide. Most of the residual sodium reacted with the carbon dioxide and water vapor to form a passivation layer of primarily sodium bicarbonate. The passivation treatment was stopped in 2005 and the primary system is maintained under a blanket of dry carbon dioxide. Approximately 670 kg of sodium metal remains in the primary system in locations that were inaccessible to passivation treatment or in pools of sodium that were too deep for complete penetration of the passivation treatment. The EBR-II reactor was permitted by the Idaho Department of Environmental Quality (DEQ) in 2002 under a RCRA permit that requires removal of all remaining sodium in the primary and secondary systems by 2022. The proposed baseline closure method would remove the large components from the primary tank, fill the primary system with water, react the remaining sodium with the water and dissolve the reaction products in the wash water. This method would generate a minimum of 100,000 gallons of caustic, liquid, low level radioactive, hazardous waste water that must be disposed of in a permitted facility. On February 19-20, 2008, a workshop was held in Idaho Falls, Idaho, to look at alternatives that could meet the RCRA permit clean closure requirements and minimize the quantity of hazardous waste generated by the cleanup process. The workshop convened a panel of national and international sodium cleanup specialists, subject matter experts from the INL, and the EBR-II Wash Water Project team that organized the workshop. The

  7. Data handling at EBR-II (Experimental Breeder Reactor II) for advanced diagnostics and control work

    SciTech Connect

    Lindsay, R.W.; Schorzman, L.W.

    1988-01-01

    Improved control and diagnostics systems are being developed for nuclear and other applications. The Experimental Breeder Reactor II (EBR-II) Division of Argonne National Laboratory has embarked on a project to upgrade the EBR-II control and data handling systems. The nature of the work at EBR-II requires that reactor plant data be readily available for experimenters, and that the plant control systems be flexible to accommodate testing and development needs. In addition, operational concerns require that improved operator interfaces and computerized diagnostics be included in the reactor plant control system. The EBR-II systems have been upgraded to incorporate new data handling computers, new digital plant process controllers, and new displays and diagnostics are being developed and tested for permanent use. In addition, improved engineering surveillance will be possible with the new systems.

  8. Technical assessment of continued wet storage of EBR-II fuel

    SciTech Connect

    Pahl, R.G.; Franklin, E.M.; Ebner, M.A.

    1996-05-01

    A technical assessment of the continued wet storage of EBR-II fuel has been made. Previous experience has shown that in-basin cladding failure occurs by intergranular attack of sensitized cladding, likely assisted by basin water chlorides. Subsequent fuel oxidation is rapid and leads to loss of configuration and release of fission products. The current inventory of EBR-II fuel stored in the ICPP basins is at risk from similar corrosion reactions.

  9. Automated start-up of EBR-II: A preview

    SciTech Connect

    Kisner, R.A.

    1989-01-01

    Oak Ridge National Laboratory (ORNL) and Argonne National Laboratory (ANL) are undertaking a joint project to develop control philosophies, strategies, and algorithms for computer control of the start-up mode of the Experimental Breeder Reactor II (EBR-II). The major objective of this project is to show that advanced liquid-metal reactor (LMR) plants can be operated from low power to full power using computer control. Development of an automated control system with this objective in view will help resolve specific issues and provide proof through demonstration that automatic control for plant start-up is feasible. This paper describes the approach that will be used to develop such a system and some of the features it is expected to have. Structured, rule-based methods, which will provide start-up capability from a variety of initial plant conditions and degrees of equipment operability, will be used for accomplishing mode changes during plant start-up. Several innovative features will be incorporated such as signal, command, and strategy validation to maximize reliability, flexibility to accommodate a wide range of plant conditions, and overall utility. Continuous control design will utilize figures of merit to evaluate how well the controller meets the mission requirements. The operator interface will have unique ''look ahead'' features to let the operator see what will happen next. 15 refs., 7 figs., 1 tab.

  10. Application of PCT to the EBR II ceramic waste form.

    SciTech Connect

    Ebert, W. L.; Lewis, M. A.; Johnson, S. G.

    2002-01-10

    We are evaluating the use of the Product Consistency Test (PCT) developed to monitor the consistency of borosilicate glass waste forms for application to the multiphase ceramic waste form (CWF) that will be used to immobilize waste salts generated during the electrometallurgical conditioning of spent sodium-bonded nuclear fuel from the Experimental Breeder Reactor No. 2 (EBR II). The CWF is a multiphase waste form comprised of about 70% sodalite, 25% borosilicate glass binder, and small amounts of halite and oxide inclusions. It must be qualified for disposal as a non-standard high-level waste (HLW) form. One of the requirements in the DOE Waste Acceptance System Requirements Document (WASRD) for HLW waste forms is that the consistency of the waste forms be monitored.[1] Use of the PCT is being considered for the CWF because of the similarities of the dissolution behaviors of both the sodalite and glass binder phases in the CWF to borosilicate HLW glasses. This paper provides (1) a summary of the approach taken in selecting a consistency test for CWF production and (2) results of tests conducted to measure the precision and sensitivity of the PCT conducted with simulated CWF.

  11. The EBR-II X501 Minor Actinide Burning Experiment

    SciTech Connect

    M. K. Meyer; S. L. Hayes; W. J. Carmack; H. Tsai

    2009-07-01

    The X501 experiment was conducted in EBR-II as part of the IFR (Integral Fast Reactor) program to demonstrate minor actinide burning through the use of a homogeneous recycle scheme. The X501 subassembly contained two metallic fuel elements loaded with relatively small quantities of americium and neptunium. Interest in the behavior of minor actinides (MA) during fuel irradiation has prompted further examination of existing X501 data, and generation of new data where needed in support of the U.S. waste transmutation effort. The X501 experiment is one of the few minor actinide-bearing fuel irradiation tests conducted worldwide and knowledge can be gained by understanding the changes in fuel behavior due to addition of MA’s. Of primary interest are the affect of the MA’s on fuel-cladding-chemical-interaction, and the redistribution behavior of americium. The quantity of helium gas release from the fuel and any effects of helium on fuel performance are also of interest. It must be stressed that information presented at this time is based on the limited PIE conducted in 1995-1996, and currently represents a set of observations rather than a complete understanding of fuel behavior. This paper provides a summary of the X501 fabrication, characterization, irradiation, and post irradiation examination.

  12. The EBR-II X501 Minor Actinide Burning Experiment

    SciTech Connect

    W. J. Carmack; M. K. Meyer; S. L. Hayes; H. Tsai

    2008-01-01

    The X501 experiment was conducted in EBR II as part of the Integral Fast Reactor program to demonstrate minor actinide burning through the use of a homogeneous recycle scheme. The X501 subassembly contained two metallic fuel elements loaded with relatively small quantities of americium and neptunium. Interest in the behavior of minor actinides (MA) during fuel irradiation has prompted further examination of existing X501 data and generation of new data where needed in support of the U.S. waste transmutation effort. The X501 experiment is one of the few MA bearing fuel irradiation tests conducted worldwide, and knowledge can be gained by understanding the changes in fuel behavior due to addition of MAs. Of primary interest are the effect of the MAs on fuel cladding chemical interaction and the redistribution behavior of americium. The quantity of helium gas release from the fuel and any effects of helium on fuel performance are also of interest. It must be stressed that information presented at this time is based on the limited PIE conducted in 1995–1996 and, currently, represents a set of observations rather than a complete understanding of fuel behavior. This report provides a summary of the X501 fabrication, characterization, irradiation, and post irradiation examination.

  13. The EBR-II X501 Minor Actinide Burning Experiment

    SciTech Connect

    Jon Carmack; S. L. Hayes; M. K. Meyer; H. Tsai

    2008-06-01

    The X501 experiment was conducted in EBR-II as part of the IFR (Integral Fast Reactor) program to demonstrate minor actinide burning through the use of a homogeneous recycle scheme. The X501 subassembly contained two metallic fuel elements loaded with relatively small quantities of americium and neptunium. Interest in the behavior of minor actinides (MA) during fuel irradiation has prompted further examination of existing X501 data, and generation of new data where needed in support of the U.S. waste transmutation effort. The X501 experiment is one of the few minor actinide-bearing fuel irradiation tests conducted worldwide and knowledge can be gained by understanding the changes in fuel behavior due to addition of MA’s. Of primary interest are the affect of the MA’s on fuel-cladding-chemical-interaction, and the redistribution behavior of americium. The quantity of helium gas release from the fuel and any effects of helium on fuel performance are also of interest. It must be stressed that information presented at this time is based on the limited PIE conducted in 1995-1996, and currently represents a set of observations rather than a complete understanding of fuel behavior.

  14. JAEA Fatigue Analysis of EBR-II Duplex Tubing

    SciTech Connect

    J. H. Jackson; D. L. Porter; W. R. Lloyd; N. Kisohara

    2011-03-01

    Small, notched three-point bend specimens machined from duplex tubes, which were extracted from an EBR-II superheater, were fatigued through the nickel interlayer to determine propensity for crack arrest within this interlayer. Several of these specimens were fatigued in the near threshold, and steady state regimes of Paris Law behavior. Additionally, two specimens were fatigued to the edge of the nickel interlayer and then monotonically loaded. Micro-hardness profiles of the nickel interlayer were also measured. Fatigue behavior was found to be similar to previous studies in that arrest was only noted in the near threshold Paris regime (attributed to the presence of voids) and in the steady state regime exhibited an acceleration of crack growth rate through the nickel interlayer followed by a slight retardation. Monotonic loading resulted in crack branching or delamination along the interlayer. Although archival material was not available for this study, the hardness of the nickel interlayer was determined to have been lowered slightly during service by comparison to the expected hardness of a similar nickel braze prepared as specified for fabrication of these tubes.

  15. Disposition of Unirradiated Sodium Bonded EBR-II Driver Fuel Elements and HEU Scrap: Work Performed for FY 2007

    SciTech Connect

    Karen A Moore

    2007-04-01

    Specific surplus high enriched uranium (HEU) materials at the Idaho National Laboratory (INL) Materials and Fuels Complex (MFC) will be transferred to a designated off-site receiving facility. The DOE High Enriched Uranium Disposition Program Office (HDPO) will determine which materials, if any, will be prepared and transferred to an off-site facility for processing and eventual fabrication of fuel for nuclear reactors. These surplus HEU materials include approximately 7200 kg unirradiated sodium-bonded EBR-II driver fuel elements, and nearly 800 kg of HEU casting scrap from the process which formed various sodium-bonded fuels (including the EBR-II driver elements). Before the driver fuel can be packaged for shipment, the fuel elements will require removal of the sodium bond. The HEU scrap will also require repackaging in preparation for off-site transport. Preliminary work on this task was authorized by BWXT Y-12 on Nov 6, 2006 and performed in three areas: • Facility Modifications • Safety Documentation • Project Management

  16. Comparison of measured and calculated composition of irradiated EBR-II blanket assemblies.

    SciTech Connect

    Grimm, K. N.

    1998-07-13

    In anticipation of processing irradiated EBR-II depleted uranium blanket subassemblies in the Fuel Conditioning Facility (FCF) at ANL-West, it has been possible to obtain a limited set of destructive chemical analyses of samples from a single EBR-II blanket subassembly. Comparison of calculated values with these measurements is being used to validate a depletion methodology based on a limited number of generic models of EBR-II to simulate the irradiation history of these subassemblies. Initial comparisons indicate these methods are adequate to meet the operations and material control and accountancy (MC and A) requirements for the FCF, but also indicate several shortcomings which may be corrected or improved.

  17. Off-normal performance of EBR-II (Experimental Breeder Reactor) driver fuel

    SciTech Connect

    Seidel, B.R.; Batte, G.L.; Lahm, C.E.; Fryer, R.M.; Koenig, J.F.; Hofman, G.L.

    1986-09-01

    The off-normal performance of EBR-II Mark-II driver fuel has been more than satisfactory as demonstrated by robust reliability under repeated transient overpower and undercooled loss-of-flow tests, by benign run-beyond-cladding-breach behavior, and by forgiving response to fabrication defects including lack of bond. Test results have verified that the metallic driver fuel is very tolerant of off-normal events. This behavior has allowed EBR-II to operate in a combined steady-state and transient mode to provide test capability without limitation from the metallic driver fuel.

  18. Vanadium alloy irradiation experiment X530 in EBR-II{sup *}

    SciTech Connect

    Tsai, H.; Strain, R.V.; Hins, A.G.

    1995-04-01

    The objective of the X530 experiment in EBR-II was to obtain early irradiation performance data, particularly the fracture properties, on the new 500-kg production heat of V-4Cr-4Ti material before the scheduled reactor shutdown at the end of September 1994.

  19. Remote, under-sodium fuel handling experience at EBR-II

    SciTech Connect

    King, R.W.; Planchon, H.P.

    1995-05-01

    The EBR-II is a pool-type design; the reactor fuel handling components and entire primary-sodium coolant system are submerged in the primary tank, which is 26 feet in diameter, 26 feet high, and contains 86,000 gallons of sodium. Since the reactor is submerged in sodium, fuel handling operations must be performed blind, making exact positioning and precision control of the fuel handling system components essential. EBR-II operated for 30 years, and the fuel handling system has performed approximately 25,000 fuel transfer operations in that time. Due to termination of the IFR program, EBR-II was shut down on September 30, 1994. In preparation for decommissioning, all fuel in the reactor will be transferred out of EBR-II to interim storage. This intensive fuel handling campaign will last approximately two years, and the number of transfers will be equivalent to the fuel handling done over about nine years of normal reactor operation. With this demand on the system, system reliability will be extremely important. Because of this increased demand, and considering that the system has been operating for about 32 years, system upgrades to increase reliability and efficiency are proceeding. Upgrades to the system to install new digital, solid state controls, and to take advantage of new visualization technology, are underway. Future reactor designs using liquid metal coolant will be able to incorporate imaging technology now being investigated, such as ultraviolet laser imaging and ultrasonic imaging.

  20. Inherent safety key performance indicators for hydrogen storage systems.

    PubMed

    Landucci, Gabriele; Tugnoli, Alessandro; Cozzani, Valerio

    2008-11-30

    The expected inherent safety performance of hydrogen storage technologies was investigated. Reference schemes were defined for alternative processes proposed for hydrogen storage, and several storage potentialities were considered. The expected safety performance of alternative process technologies was explored estimating key performance indicators based on consequence assessment and credit factors of possible loss of containment events. The results indicated that the potential hazard is always lower for the innovative technologies proposed for hydrogen storage, as metal or complex hydrides. This derived mainly from the application of the inherent safety principles of "substitution" and "moderation", since in these processes hydrogen is stored as a less hazardous hydride. However, the results also evidenced that in the perspective of an industrial implementation of these technologies, the reliability of the auxiliary equipment will be a critical issue to be addressed. PMID:18395975

  1. Technical Information on the Carbonation of the EBR-II Reactor, Summary Report Part 2: Application to EBR-II Primary Sodium System and Related Systems

    SciTech Connect

    Steven R. Sherman; Collin J. Knight

    2006-03-01

    Residual sodium is defined as sodium metal that remains behind in pipes, vessels, and tanks after the bulk sodium metal has been melted and drained from such components. The residual sodium has the same chemical properties as bulk sodium, and differs from bulk sodium only in the thickness of the sodium deposit. Typically, sodium is considered residual when the thickness of the deposit is less than 5-6 cm. This residual sodium must be removed or deactivated when a pipe, vessel, system, or entire reactor is permanently taken out of service, in order to make the component or system safer and/or to comply with decontamination and decomissioning regulations. As an alternative to the established residual sodium deactivation techniques (steam-and-nitrogen, wet vapor nitrogen, etc.), a technique involving the use of moisture and carbon dioxide has been developed. With this technique, sodium metal is converted into sodium bicarbonate by reacting it with humid carbon dioxide. Hydrogen is emitted as a by-product. This technique was first developed in the laboratory by exposing sodium samples to humidifed carbon dioxide under controlled conditions, and then demonstrated on a larger scale by treating residual sodium within the Experimental Breeder Reactor II (EBR-II) secondary cooling system, followed by the primary cooling system, respectively. The EBR-II facility is located at the Idaho National Laboratory (INL) in southeastern Idaho, USA. This report is Part 2 of a two-part report. This second report provides a supplement to the first report and describes the application of the humdidified carbon dioxide technique ("carbonation") to the EBR-II primary tank, primary cover gas systems, and the intermediate heat exchanger. Future treatment plans are also provided.

  2. Technical Information on the Carbonation of the EBR-II Reactor, Summary Report Part 1: Laboratory Experiments and Application to EBR-II Secondary Sodium System

    SciTech Connect

    Steven R. Sherman

    2005-04-01

    Residual sodium is defined as sodium metal that remains behind in pipes, vessels, and tanks after the bulk sodium metal has been melted and drained from such components. The residual sodium has the same chemical properties as bulk sodium, and differs from bulk sodium only in the thickness of the sodium deposit. Typically, sodium is considered residual when the thickness of the deposit is less than 5-6 cm. This residual sodium must be removed or deactivated when a pipe, vessel, system, or entire reactor is permanently taken out of service, in order to make the component or system safer and/or to comply with decommissioning regulations. As an alternative to the established residual sodium deactivation techniques (steam-and-nitrogen, wet vapor nitrogen, etc.), a technique involving the use of moisture and carbon dioxide has been developed. With this technique, sodium metal is converted into sodium bicarbonate by reacting it with humid carbon dioxide. Hydrogen is emitted as a by-product. This technique was first developed in the laboratory by exposing sodium samples to humidified carbon dioxide under controlled conditions, and then demonstrated on a larger scale by treating residual sodium within the Experimental Breeder Reactor II (EBR-II) secondary cooling system, followed by the primary cooling system, respectively. The EBR-II facility is located at the Idaho National Laboratory (INL) in southeastern Idaho, U.S.A. This report is Part 1 of a two-part report. It is divided into three sections. The first section describes the chemistry of carbon dioxide-water-sodium reactions. The second section covers the laboratory experiments that were conducted in order to develop the residual sodium deactivation process. The third section discusses the application of the deactivation process to the treatment of residual sodium within the EBR-II secondary sodium cooling system. Part 2 of the report, under separate cover, describes the application of the technique to residual sodium

  3. Thermal-hydraulic-structural behavior of the EBR-II IHX for overpower transients

    SciTech Connect

    Mohr, D.; Chang, L.K.; Lee, M.J.; Feldman, E.E.

    1982-01-01

    A detailed study has been made of the effects of the Operational Reliability Testing (ORT) program on major plant components of the Experimental Breeder Reactor No. II (EBR-II). This paper describes the integrated thermal-hydraulic-structural analyses conducted for the intermediate heat exchanger (IHX) with the aid of the NATDEMO, THTB, and ANSYS codes. An extensive analysis revealed the stress limiting area to be the junction between the upper head and upper tube sheet. The analyses indicate, however, that the EBR-II IHX, the major plant component most affected by the ORT program, will be able to withstand the thermal stress and accumulated fatigue damage during the lifetime of the plant including the ORT program.

  4. Feasibility of Ground Testing a Moon and Mars Surface Power Reactor in EBR-II

    SciTech Connect

    Sheryl Morton; Carl Baily; Tom Hill; Jim Werner

    2006-02-01

    Ground testing of a surface fission power system would be necessary to verify the design and validate reactor performance to support safe and sustained human exploration of the Moon and Mars. The Idaho National Laboratory (INL) has several facilities that could be adapted to support a ground test. This paper focuses on the feasibility of ground testing at the Experimental Breeder Reactor II (EBR-II) facility and using other INL existing infrastructure to support such a test. This brief study concludes that the INL EBR-II facility and supporting infrastructure are a viable option for ground testing the surface power system. It provides features and attributes that offer advantages to locating and performing ground testing at this site, and it could support the National Aeronautics and Space Administration schedules for human exploration of the Moon. This study used the initial concept examined by the U.S. Department of Energy Inter-laboratory Design and Analysis Support Team for surface power, a lowtemperature, liquid-metal, three-loop Brayton power system. With some facility modification, the EBR-II can safely house a test chamber and perform long-term testing of the space reactor power system. The INL infrastructure is available to receive and provide bonded storage for special nuclear materials. Facilities adjacent to EBR-II can provide the clean room environment needed to assemble and store the test article assembly, disassemble the power system at the conclusion of testing, and perform posttest examination. Capability for waste disposal is also available at the INL.

  5. Feasibility of Ground Testing a Moon and Mars Surface Power Reactor in EBR-II

    SciTech Connect

    Morton, Sheryl L.; Baily, Carl E.; Hill, Thomas J.; Werner, James E.

    2006-01-20

    Ground testing of a surface fission power system would be necessary to verify the design and validate reactor performance to support safe and sustained human exploration of the Moon and Mars. The Idaho National Laboratory (INL) has several facilities that could be adapted to support a ground test. This paper focuses on the feasibility of ground testing at the Experimental Breeder Reactor II (EBR-II) facility and using other INL existing infrastructure to support such a test. This brief study concludes that the INL EBR-II facility and supporting infrastructure are a viable option for ground testing the surface power system. It provides features and attributes that offer advantages to locating and performing ground testing at this site, and it could support the National Aeronautics and Space Administration schedules for human exploration of the Moon. This study used the initial concept examined by the U.S. Department of Energy Inter-laboratory Design and Analysis Support Team for surface power, a low-temperature, liquid-metal, three-loop Brayton power system. With some facility modification, the EBR-II can safely house a test chamber and perform long-term testing of the space reactor power system. The INL infrastructure is available to receive and provide bonded storage for special nuclear materials. Facilities adjacent to EBR-II can provide the clean room environment needed to assemble and store the test article assembly, disassemble the power system at the conclusion of testing, and perform posttest examination. Capability for waste disposal is also available at the INL.

  6. Feasibility of Ground Testing a Moon and Mars Surface Power Reactor in EBR-II

    NASA Astrophysics Data System (ADS)

    Morton, Sheryl L.; Baily, Carl E.; Hill, Thomas J.; Werner, James E.

    2006-01-01

    Ground testing of a surface fission power system would be necessary to verify the design and validate reactor performance to support safe and sustained human exploration of the Moon and Mars. The Idaho National Laboratory (INL) has several facilities that could be adapted to support a ground test. This paper focuses on the feasibility of ground testing at the Experimental Breeder Reactor II (EBR-II) facility and using other INL existing infrastructure to support such a test. This brief study concludes that the INL EBR-II facility and supporting infrastructure are a viable option for ground testing the surface power system. It provides features and attributes that offer advantages to locating and performing ground testing at this site, and it could support the National Aeronautics and Space Administration schedules for human exploration of the Moon. This study used the initial concept examined by the U.S. Department of Energy Inter-laboratory Design and Analysis Support Team for surface power, a low-temperature, liquid-metal, three-loop Brayton power system. With some facility modification, the EBR-II can safely house a test chamber and perform long-term testing of the space reactor power system. The INL infrastructure is available to receive and provide bonded storage for special nuclear materials. Facilities adjacent to EBR-II can provide the clean room environment needed to assemble and store the test article assembly, disassemble the power system at the conclusion of testing, and perform posttest examination. Capability for waste disposal is also available at the INL.

  7. A simple graphical method for measuring inherent safety.

    PubMed

    Gupta, J P; Edwards, David W

    2003-11-14

    Inherently safer design (ISD) concepts have been with us for over two decades since their elaboration by Kletz [Chem. Ind. 9 (1978) 124]. Interest has really taken off globally since the early nineties after several major mishaps occurred during the eighties (Bhopal, Mexico city, Piper-alfa, Philips Petroleum, to name a few). Academic and industrial research personnel have been actively involved into devising inherently safer ways of production. The regulatory bodies have also shown deep interest since ISD makes the production safer and hence their tasks easier. Research funding has also been forthcoming for new developments as well as for demonstration projects.A natural question that arises is as to how to measure ISD characteristics of a process? Several researchers have worked on this [Trans. IChemE, Process Safety Environ. Protect. B 71 (4) (1993) 252; Inherent safety in process plant design, Ph.D. Thesis, VTT Publication Number 384, Helsinki University of Technology, Espoo, Finland, 1999; Proceedings of the Mary Kay O'Connor Process Safety Center Symposium, 2001, p. 509]. Many of the proposed methods are very elegant, yet too involved for easy adoption by the industry which is scared of yet another safety analysis regime. In a recent survey [Trans. IChemE, Process Safety Environ. Prog. B 80 (2002) 115], companies desired a rather simple method to measure ISD. Simplification is also an important characteristic of ISD. It is therefore desirable to have a simple ISD measurement procedure. The ISD measurement procedure proposed in this paper can be used to differentiate between two or more processes for the same end product. The salient steps are: Consider each of the important parameters affecting the safety (e.g., temperature, pressure, toxicity, flammability, etc.) and the range of possible values these parameters can have for all the process routes under consideration for an end product. Plot these values for each step in each process route and compare. No

  8. Swelling, microstructural development and helium effects in type 316 stainless steel irradiated in HFIR and EBR-II

    SciTech Connect

    Maziasz, P.J.; Grossbeck, M.L.

    1981-01-01

    This work examines the swelling and microstructural development of a single heat of 20%-cold-worked type 316 stainless steel irradiated to produce displacement damage and a high, continuous helium generation rate, in the High Flux Isotope Reactor (HFIR). Similar irradiation of the same heat of steel in the Experimental Breeder Reactor (EBR)-II is used as a base line for comparing displacement damage accompanying a very low continuous helium generation rate. At temperatures above and below the void swelling regime (approx. 350 to 625/sup 0/C) swelling is greater in HFIR than in EBR-II. In the temprature range of 350 to 625/sup 0/C, cavity formation, precipitation and dislocation recovery are both enhanced and accelerated in HFIR, often causing swelling at lower dose than in EBR-II. In HFIR, however, cavities appear to be bubbles rather than voids. They are about 10 times smaller and 20 to 50 times more numerous than voids in EBR-II. Thus, the swelling becomes greater in EBR-II than in HFIR for 20%-CW 316 in the void swelling temperature ranges as fluence increases. Such differences in swelling and microstructural behavior must be understood in order to anticipate the behavior of materials during fusion irradiation.

  9. Experimental Breeder Reactor II (EBR-II) Fuel-Performance Test Facility (FPTF)

    SciTech Connect

    Pardini, J.A.; Brubaker, R.C.; Veith, D.J.; Giorgis, G.C.; Walker, D.E.; Seim, O.S.

    1982-01-01

    The Fuel-Performance Test Facility (FPTF) is the latest in a series of special EBR-II instrumented in-core test facilities. A flow control valve in the facility is programmed to vary the coolant flow, and thus the temperature, in an experimental-irradiation subassembly beneath it and coupled to it. In this way, thermal transients can be simulated in that subassembly without changing the temperatures in surrounding subassemblies. The FPTF also monitors sodium flow and temperature, and detects delayed neutrons in the sodium effluent from the experimental-irradiation subassembly beneath it. This facility also has an acoustical detector (high-temperature microphone) for detecting sodium boiling.

  10. Simulation of LMFBR pump transients and comparison to LOF that occurred at EBR-II

    SciTech Connect

    Koenig, F.F.; Dean, E.M.

    1985-01-01

    In a large LMFBR plant design, a number of pumps in parallel will feed the core. It must be demonstrated that the plant can continue to operate with the loss of one of the primary pumps. It is desirable not to have check valves in the loop from a reliability and economic standpoint. Simulations have been made to determine the consequences of a loss of one pump in a four-loop pool plant in which no plant protection action is taken. This analysis would be used to determine the required power rundown that would accompany pump loss. The two primary centrifugal pumps in EBR-II feed the core and blanket plenums in two parallel flow paths. The loss of one pump will result in decrease core flow and reverse flow through the down pump since no check valves are present in the system. For a large pool plant with four primary pumps, the loss of one pump will also result in reverse flow through the down pump if check valves of flow diodes are not included. The resulting flow transient has been modeled for EBR-II and the large plant using the DNSP program.

  11. Operating experience of the EBR-II intermediate heat exchanger and the steam generator system

    SciTech Connect

    Buschman, H.W.; Longua, K.J.; Penney, W.H.

    1983-01-01

    Experimental Breeder Reactor-II (EBR-II) is an experimental liquid metal fast breeder reactor located at the Idaho National Engineering Laboratory. It consists of an unmoderated, heterogeneous, sodium-cooled reactor with a nominal thermal power output of 62.5 MW; an intermediate closed loop of secondary sodium coolant; and a steam plant that produces 20 MW of electrical power through a conventional turbine generator. The EBR-II heat transport system continues to operate satisfactorily after 18 years. This represents about 89,000 hours of steaming, which results in a total integrated thermal power production of about 215,000 MWd. In this time, the steam generator has experienced over 580 plant startups and 349 reactor scrams. The plant capacity factor for the past five years has been in excess of 70%, and in fact has averaged almost 60% over the last thirteen years. This excellent record is partly attributable to the trouble-free operation of the steam generator which, aside from an initial construction tube-to-tubesheet weld defect, has had a plant availability of 100%.

  12. Mitigation of Severe Accident Consequences Using Inherent Safety Principles

    SciTech Connect

    R. A. Wigeland; J. E. Cahalan

    2009-12-01

    Sodium-cooled fast reactors are designed to have a high level of safety. Events of high probability of occurrence are typically handled without consequence through reliable engineering systems and good design practices. For accidents of lower probability, the initiating events are characterized by larger and more numerous challenges to the reactor system, such as failure of one or more major engineered systems and can also include a failure to scram the reactor in response. As the initiating conditions become more severe, they have the potential for creating serious consequences of potential safety significance, including fuel melting, fuel pin disruption and recriticality. If the progression of such accidents is not mitigated by design features of the reactor, energetic events and dispersal of radioactive materials may result. For severe accidents, there are several approaches that can be used to mitigate the consequences of such severe accident initiators, which typically include fuel pin failures and core disruption. One approach is to increase the reliability of the reactor protection system so that the probability of an ATWS event is reduced to less than 1 x 10-6 per reactor year, where larger accident consequences are allowed, meeting the U.S. NRC goal of relegating such accident consequences as core disruption to these extremely low probabilities. The main difficulty with this approach is to convincingly test and guarantee such increased reliability. Another approach is to increase the redundancy of the reactor scram system, which can also reduce the probability of an ATWS event to a frequency of less than 1 x 10-6 per reactor year or lower. The issues with this approach are more related to reactor core design, with the need for a greater number of control rod positions in the reactor core and the associated increase in complexity of the reactor protection system. A third approach is to use the inherent reactivity feedback that occurs in a fast reactor to

  13. Expert system applications in support of system diagnostics and prognostics at EBR-II

    SciTech Connect

    Lehto, W.K.; Gross, K.C.; Argonne National Lab., IL )

    1989-01-01

    Expert systems have been developed to aid in the monitoring and diagnostics of the Experimental Breeder Reactor-II (EBR-II) at the Idaho National Engineering Laboratory (INEL) in Idaho Falls, Idaho. Systems have been developed for failed fuel surveillance and diagnostics and reactor coolant pump monitoring and diagnostics. A third project is being done jointly by ANL-W and EG G Idaho to develop a transient analysis system to enhance overall plant diagnostic and prognostic capability. The failed fuel surveillance and diagnosis system monitors, processes, and interprets information from nine key plant sensors. It displays to the reactor operator diagnostic information needed to make proper decisions regarding technical specification conformance during reactor operation with failed fuel. 8 refs., 9 figs., 2 tabs.

  14. Seventeen years of LMFBR experience: Experimental Breeder Reactor II (EBR-II)

    SciTech Connect

    Perry, W.H.; Lentz, G.L.; Richardson, W.J.; Wolz, G.C.

    1982-01-01

    Operating experience at EBR-II over the past 17 years has shown that a sodium-cooled pool-type reactor can be safely and efficiently operated and maintained. The reactor has performed predictably and benignly during normal operation and during both unplanned and planned plant upsets. The duplex-tube evaporators and superheaters have never experienced a sodium/water leak, and the rest of the steam-generating system has operated without incident. There has been no noticeable degradation of the heat transfer efficiency of the evaporators and superheaters, except for the one superheater replaced in 1981. There has been no need to perform any chemical cleaning of steam-system components.

  15. Response of EBR-II to a complete loss of primary forced flow during power operation

    SciTech Connect

    Singer, R.M.; Gillette, J.L.; Mohr, D.; Tokar, J.V.; Sullivan, J.E.; Dean, E.M.

    1980-01-01

    Detailed measurements of the thermal, hydraulic, and neutronic response of EBR-II to a complete loss of primary forced flow followed by a PPS-activated scram are presented. The experimental results clearly indicate a smooth transition to natural convective flow with a quite modest incore temperature transient. The accompanying calculations using the NATDEMO code agree quite well with the measured temperatures and flow rates throughout the primary system. The only region of the plant where a significant discrepancy between the measurements and calculations occurred was in the IHX. The reasons for this result could not be definitively determined, but it is speculated that the one-dimensional assumptions used in the modeling may not be valid in the IHX during buoyancy driver flows.

  16. The EBR-II materials-surveillance program. 5: Results of SURV-5.

    SciTech Connect

    Ruther, W.E.; Staffon, J.D.; Carlson, B.G.; Allen, T.R.

    1998-01-01

    In March of 1965, a set of surveillance (SURV) samples was placed in the EBR-II reactor to determine the effect of irradiation, thermal aging, and sodium corrosion on reactor materials. Eight subassemblies were placed into row 12 positions of EBR-II to determine the effect of irradiation at 370 C. Two subassemblies were placed into the primary sodium basket to determine the effect of thermal aging at 370 C. One half of all samples were exposed to primary system sodium while one half were sealed in capsules with a helium atmosphere. Fifteen different structural materials were tested in the SURV program. In this work, the properties of these materials irradiated at 370 C to a total fluence of 3.2 {times} 10{sup 22} n/cm{sup 2} were determined. These materials are the fifth set of irradiated subassemblies to be examined as part of the SURV program (SURV-5). The properties analyzed were weight, density, microstructure, hardness, tensile and yield strength, and fracture resistance. Of all the alloys examined in SURV-5, only Berylco-25 showed any significant weight loss. Stainless steel (both 304 and 347) had the largest density decrease, although the density decrease from irradiation for all alloys was less than 0.4 percent. The microstructure of both Berylco-25 and the aluminum-bronze alloy was altered significantly. Iron- and nickel-base alloys showed little change in microstructure. Austenitic steels (304 and 347) harden with irradiation. The hardness of Inconel X750 did not change significantly with irradiation. The ultimate tensile strength of Inconel X750, 304 stainless steel, 420 stainless steel and welded 304 changed little due to a fluence increase from 2.2 {times} 10{sup 22} n/cm{sup 2} (the maximum fluence of the SURV-4 samples) to 3.2 {times} 10{sup 22} n/cm{sup 2}.

  17. Safety assessment in plant layout design using indexing approach: implementing inherent safety perspective. Part 1 - guideword applicability and method description.

    PubMed

    Tugnoli, Alessandro; Khan, Faisal; Amyotte, Paul; Cozzani, Valerio

    2008-12-15

    Layout planning plays a key role in the inherent safety performance of process plants since this design feature controls the possibility of accidental chain-events and the magnitude of possible consequences. A lack of suitable methods to promote the effective implementation of inherent safety in layout design calls for the development of new techniques and methods. In the present paper, a safety assessment approach suitable for layout design in the critical early phase is proposed. The concept of inherent safety is implemented within this safety assessment; the approach is based on an integrated assessment of inherent safety guideword applicability within the constraints typically present in layout design. Application of these guidewords is evaluated along with unit hazards and control devices to quantitatively map the safety performance of different layout options. Moreover, the economic aspects related to safety and inherent safety are evaluated by the method. Specific sub-indices are developed within the integrated safety assessment system to analyze and quantify the hazard related to domino effects. The proposed approach is quick in application, auditable and shares a common framework applicable in other phases of the design lifecycle (e.g. process design). The present work is divided in two parts: Part 1 (current paper) presents the application of inherent safety guidelines in layout design and the index method for safety assessment; Part 2 (accompanying paper) describes the domino hazard sub-index and demonstrates the proposed approach with a case study, thus evidencing the introduction of inherent safety features in layout design. PMID:18406519

  18. Comparison of swelling and cavity microstructural development for type 316 stainless steel irradiated in EBR-II and HFIR

    SciTech Connect

    Maziasz, P.J.

    1983-01-01

    Comparison of swelling and cavity microstructures for one heat of 20% cold-worked (CW) type 316 stainless steel (316) irradiated at 500 to 650/sup 0/C in EBR-II (up to 75 dpa) and HFIR (up to 61 dpa) suggests that void growth and swelling are suppressed by the higher helium generation found in HFIR. Instead of voids, many small bubbles develop in the CW 316 in HFIR and resist conversion to voids. However, similar comparison of solution-annealed (SA) 316 irradiated in EBR-II and HFIR at 500 to 550/sup 0/C leads to an opposite conclusion; void swelling is enhanced by helium in HFIR. Many more bubbles nucleate in SA 316 at low fluence in HFIR compared to EBR-II, but bimodel distributions and rapid coarsening eventually lead to high swelling due to high concentrations of matrix ands precipitate-associated voids in HFIR. A key to the swelling resistance of the CW 316 in HFIR appears to be the development of a sufficiently cavity-dominated sink system in the early stages of evolution.

  19. Fatigue Testing of Metallurgically-Bonded EBR-II Superheater Tubes

    SciTech Connect

    Terry C. Totemeier

    2006-12-01

    Fatigue crack growth tests were performed on 2¼Cr-1Mo steel specimens machined from ex-service Experimental Breeder Reactor – II (EBR-II) superheater duplex tubes. The tubes had been metallurgically bonded with a 100 µm thick Ni interlayer; the specimens incorporated this bond layer. Tests were performed at room temperature in air and at 400°C in air and humid Ar; cracks were grown at varied levels of constant ?K. Crack growth tests at a range of ?K were also performed on specimens machined from the shell of the superheater. In all conditions the presence of the Ni interlayer was found to result in a net retardation of growth as the crack passed through the interlayer. The mechanism of retardation was identified as a disruption of crack planarity and uniformity after passing through the porous interlayer. Full crack arrest was only observed in a single test performed at near-threshold ?K level (12 MPa?m) at 400°C. In this case the crack tip was blunted by oxidation of the base steel at the steel-interlayer interface.

  20. SCALE UP OF CERAMIC WASTE FORMS FOR THE EBR-II SPENT FUEL TREATMENT PROCESS

    SciTech Connect

    Matthew C. Morrison; Kenneth J. Bateman; Michael F. Simpson

    2010-11-01

    ABSTRACT SCALE UP OF CERAMIC WASTE FORMS FOR THE EBR-II SPENT FUEL TREATMENT PROCESS Matthew C. Morrison, Kenneth J. Bateman, Michael F. Simpson Idaho National Laboratory, P.O. Box 1625, Idaho Falls, ID 83415 The ceramic waste process is the intended method for disposing of waste salt electrolyte, which contains fission products from the fuel-processing electrorefiners (ER) at the INL. When mixed and processed with other materials, the waste salt can be stored in a durable ceramic waste form (CWF). The development of the CWF has recently progressed from small-scale testing and characterization to full-scale implementation and experimentation using surrogate materials in lieu of the ER electrolyte. Two full-scale (378 kg and 383 kg) CWF test runs have been successfully completed with final densities of 2.2 g/cm3 and 2.1 g/cm3, respectively. The purpose of the first CWF was to establish material preparation parameters. The emphasis of the second pre-qualification test run was to evaluate a preliminary multi-section CWF container design. Other considerations were to finalize material preparation parameters, measure the material height as it consolidates in the furnace, and identify when cracking occurs during the CWF cooldown process.

  1. Midplane and off-midplane axial leakage simulation of heterogeneous subassemblies in EBR-II

    SciTech Connect

    Grimm, K.N.; Meneghetti, D.

    1984-01-01

    Generally EBR-II XY geometry and one-dimensional (1D) cylindrical neutron flux calculations using transport theory analysis assume energy independent DB/sup 2/-type absorptions to simulate effects of axial leakages. This assumption, while generally resulting in satisfactory eigenvalues and high- and intermediate-energy flux spectra, gives large errors in the low-energy flux spectra where the flux levels are smaller. These midplane errors, and more importantly the off-midplane errors, can be reduced by using a more realistic leakage model: space and energy dependent leakage absorption cross sections. Analyses have been reported in which transport theory methods using row-wise azimuthally-homogeneous RZ-geometry boundary angular fluxes to calculate space and energy dependent leakage absorptions which were then used in subsequent 1D cylindrical simulations of RZ calculations. The present paper extends the study to include heterogeneous core loading configurations. This study contains modeling of heterogeneous XYZ loadings using heterogeneous XY geometry and space and energy dependent leakage absorptions. Because of the complexities arising from the three-dimensional analysis, the results presented here use diffusion theory. Although the actual negative leakage absorption values can be used in the CITATION diffusion theory code, it was found that the ..sigma../sub s/(1..-->..g) method gave better results in the core region of these studies.

  2. Visual imagery and the user model applied to fuel handling at EBR-II

    SciTech Connect

    Brown-VanHoozer, S.A.

    1995-06-01

    The material presented in this paper is based on two studies involving visual display designs and the user`s perspective model of a system. The studies involved a methodology known as Neuro-Linguistic Programming (NLP), and its use in expanding design choices which included the ``comfort parameters`` and ``perspective reality`` of the user`s model of the world. In developing visual displays for the EBR-II fuel handling system, the focus would be to incorporate the comfort parameters that overlap from each of the representation systems: visual, auditory and kinesthetic then incorporate the comfort parameters of the most prominent group of the population, and last, blend in the other two representational system comfort parameters. The focus of this informal study was to use the techniques of meta-modeling and synesthesia to develop a virtual environment that closely resembled the operator`s perspective of the fuel handling system of Argonne`s Experimental Breeder Reactor - II. An informal study was conducted using NLP as the behavioral model in a v reality (VR) setting.

  3. Tensile properties of vanadium alloys irradiated at 390{degrees}C in EBR-II

    SciTech Connect

    Chung, H.M.; Tsai, H.C.; Nowicki, L.J.

    1997-08-01

    Vanadium alloys were irradiated in Li-bonded stainless steel capsules to {approx}390{degrees}C in the EBR-II X-530 experiment. This report presents results of postirradiation tests of tensile properties of two large-scale (100 and 500 kg) heats of V-4Cr-Ti and laboratory (15-30 kg) heats of boron-doped V-4Cr-4Ti, V-8Cr-6Ti, V-5Ti, and V-3Ti-1Si alloys. Tensile specimens, divided into two groups, were irradiated in two different capsules under nominally similar conditions. The 500-kg heat (No. 832665) and the 100-kg heat (VX-8) of V-4Cr-4Ti irradiated in one of the subcapsules exhibited complete loss of work-hardening capability, which was manifested by very low uniform plastic strain. In contrast, the 100-kg heat of V-4Cr-4Ti irradiated in another subcapsule exhibited good tensile properties (uniform plastic strain 2.8-4.0%). A laboratory heat of V-3Ti-1Si irradiated in the latter subcapsule also exhibited good tensile properties. These results indicate that work-hardening capability at low irradiation temperatures varies significantly from heat to heat and is influenced by nominally small differences in irradiation conditions.

  4. Initiating the D&D Project for the EBR-II

    SciTech Connect

    Rick Demmer

    2010-08-01

    A novel decommissioning project is underway to close the Experimental Breeder Reactor-II (EBR-II) “fast” reactor at the Idaho National Laboratory (INL), Materials and Fuels Complex (MFC) facility near Idaho Falls, ID. The facility was placed in cold shutdown in 1994 and work began on the removal of the metallic sodium coolant. The bulk of the sodium was drained and treated beginning in 2001. The residual sodium heel was chemically passivated to render it less reactive in 2005 using a novel carbon dioxide treatment. Approximately 700 kg of metallic sodium and 3500 kg of sodium bicarbonate remain in the facility. A RCRA Waste Treatment Permit, issued in 2002 by the State of Idaho Department of Environmental Quality, requires annual progress toward closure of the facility, and that all regulated materials be removed or deactivated, and the waste products removed by 2022. The baseline sodium removal technology would result in about 100,000 gallons of low-level waste solution requiring treatment along with separate handling of the large components (intermediate heat exchanger, rotating plug, etc) outside of the primary tank.

  5. Fatigue Testing of Metallurgically-Bonded EBR-II Superheater Tubes

    SciTech Connect

    T.C. Totemeier; D.M. Wachs; D.L. Porter

    2008-05-01

    Fatigue crack growth and impact tests were performed on 2¼Cr-1Mo steel specimens machined from ex-service Experimental Breeder Reactor – II (EBR-II) superheater duplex tubes. The tubes had been metallurgically bonded with a 100 µm thick Ni layer; the specimens incorporated this bond layer. Impact tests were performed at temperatures from –50 to 400°C; cracks propagating from the V-notch were arrested by delamination at the bond layer for all tests with one exception at –50°C. Fatigue crack growth tests were performed at room temperature in air and at 400°C in air and humid Ar; cracks were grown at varied levels of constant ?K. In all conditions the presence of the Ni bond layer was found to result in a net retardation of growth as the crack passed through the layer. The mechanism of retardation was identified as a disruption of crack planarity and uniformity after passing through the porous bond layer. Full crack arrest was only observed in a single test performed at near-threshold ?K level (12 MPa?m) at 400°C. In this case the crack tip was blunted by oxidation of the base steel at the steel-nickel interface.

  6. Static leach tests with the EBR-II metallic waste form.

    SciTech Connect

    Ebert, W. L.; Lewis, M. A.; Barber, T. L.; DiSanto, T.; Johnson, S. G.

    2004-01-09

    A metallic waste form (MWF) will be used to immobilize contaminated cladding hulls recovered after electrometallurgical treatment of spent sodium-bonded nuclear fuel from the Experimental Breeder Reactor-II (EBR-II). Tests were conducted to determine if the high-level waste (HLW) glass degradation model developed for total system performance assessment (TSPA) calculations for the Yucca Mountain repository system can be used to represent the degradation of disposed MWF. Static tests were conducted at 50, 70, and 90 C with monolithic samples of MWF in pH buffer solutions spiked with NaCl at a MWF surface-to-solution volume ratio of about 200 m{sup -1}. Test specimens were prepared from a surrogate MWF ingot containing about 10 mass% U. Solutions were exchanged after 14, 28, and 70 days. The cumulative amount of U released into solution through 70 days was used to calculate the MWF degradation rate for each test condition. The rate was independent of temperature. The rate was highest in acidic solutions, lowest in neutral solutions, and intermediate in alkaline solutions. The uranium release rate from a breached canister, which is the product of the MWF degradation rate and the surface area of two MWF ingots in a canister, was compared with the release rate calculated with the HLW glass degradation model for a glass log at the same temperature and pH values. The uranium release rates measured for MWF are less than the degradation rates calculated for HLW glass (compared on a mass per time basis).

  7. Validation of the integration of CFD and SAS4A/SASSYS-1: Analysis of EBR-II shutdown heat removal test 17

    SciTech Connect

    Thomas, J. W.; Fanning, T. H.; Vilim, R.; Briggs, L. L.

    2012-07-01

    Recent analyses have demonstrated the need to model multidimensional phenomena, particularly thermal stratification in outlet plena, during safety analyses of loss-of-flow transients of certain liquid-metal cooled reactor designs. Therefore, Argonne's reactor systems safety code SAS4A/SASSYS-1 is being enhanced by integrating 3D computational fluid dynamics models of the plena. A validation exercise of the new tool is being performed by analyzing the protected loss-of-flow event demonstrated by the EBR-II Shutdown Heat Removal Test 17. In this analysis, the behavior of the coolant in the cold pool is modeled using the CFD code STAR-CCM+, while the remainder of the cooling system and the reactor core are modeled with SAS4A/SASSYS-1. This paper summarizes the code integration strategy and provides the predicted 3D temperature and velocity distributions inside the cold pool during SHRT-17. The results of the coupled analysis should be considered preliminary at this stage, as the exercise pointed to the need to improve the CFD model of the cold pool tank. (authors)

  8. Identification and characterization of passive safety system and inherent safety feature building blocks for advanced light-water reactors

    SciTech Connect

    Forsberg, C.W.

    1989-01-01

    Oak Ridge National Laboratory (ORNL) is investigating passive and inherent safety options for Advanced Light-Water Reactors (ALWRs). A major activity in 1989 includes identification and characterization of passive safety system and inherent safety feature building blocks, both existing and proposed, for ALWRs. Preliminary results of this work are reported herein. This activity is part of a larger effort by the US Department of Energy, reactor vendors, utilities, and others in the United States to develop improved LWRs. The Advanced Boiling Water Reactor (ABWR) program and the Advanced Pressurized Water Reactor (APWR) program have as goals improved, commercially available LWRs in the early 1990s. The Advanced Simplified Boiling Water Reactor (ASBWR) program and the AP-600 program are developing more advanced reactors with increased use of passive safety systems. It is planned that these reactors will become commercially available in the mid 1990s. The ORNL program is an exploratory research program for LWRs beyond the year 2000. Desired long-term goals for such reactors include: (1) use of only passive and inherent safety, (2) foolproof against operator errors, (3) malevolence resistance against internal sabotage and external assault and (4) walkaway safety. The acronym ''PRIME'' (Passive safety, Resilient operation, Inherent safety, Malevolence resistance, and Extended (walkaway) safety) is used to summarize these desired characteristics. Existing passive and inherent safety options are discussed in this document.

  9. Passive and inherent safety technologies for light-water nuclear reactors

    SciTech Connect

    Forsberg, C.W.

    1990-07-01

    Passive/inherent safety implies a technical revolution in our approach to nuclear power safety. This direction is discussed herein for light-water reactors (LWRs) -- the predominant type of power reactor used in the world today. At Oak Ridge National Laboratory (ORNL) the approach to the development of passive/inherent safety for LWRs consists of four steps: identify and quantify safety requirements and goals; identify and quantify the technical functional requirements needed for safety; identify, invent, develop, and quantify technical options that meet both of the above requirements; and integrate safety systems into designs of economic and reliable nuclear power plants. Significant progress has been achieved in the first three steps of this program. The last step involves primarily the reactor vendors. These activities, as well as related activities worldwide, are described here. 27 refs., 7 tabs.

  10. The research of distributed interactive simulation based on HLA in coal mine industry inherent safety

    NASA Astrophysics Data System (ADS)

    Dou, Zhi-Wu

    2010-08-01

    To solve the inherent safety problem puzzling the coal mining industry, analyzing the characteristic and the application of distributed interactive simulation based on high level architecture (DIS/HLA), a new method is proposed for developing coal mining industry inherent safety distributed interactive simulation adopting HLA technology. Researching the function and structure of the system, a simple coal mining industry inherent safety is modeled with HLA, the FOM and SOM are developed, and the math models are suggested. The results of the instance research show that HLA plays an important role in developing distributed interactive simulation of complicated distributed system and the method is valid to solve the problem puzzling coal mining industry. To the coal mining industry, the conclusions show that the simulation system with HLA plays an important role to identify the source of hazard, to make the measure for accident, and to improve the level of management.

  11. Criticality Safety Evaluation of the LLNL Inherently Safe Subcritical Assembly (ISSA)

    SciTech Connect

    Percher, Catherine

    2012-06-19

    The LLNL Nuclear Criticality Safety Division has developed a training center to illustrate criticality safety and reactor physics concepts through hands-on experimental training. The experimental assembly, the Inherently Safe Subcritical Assembly (ISSA), uses surplus highly enriched research reactor fuel configured in a water tank. The training activities will be conducted by LLNL following the requirements of an Integration Work Sheet (IWS) and associated Safety Plan. Students will be allowed to handle the fissile material under the supervision of LLNL instructors. This report provides the technical criticality safety basis for instructional operations with the ISSA experimental assembly.

  12. Worldwide advanced nuclear power reactors with passive and inherent safety: What, why, how, and who

    SciTech Connect

    Forsberg, C.W.; Reich, W.J.

    1991-09-01

    The political controversy over nuclear power, the accidents at Three Mile Island (TMI) and Chernobyl, international competition, concerns about the carbon dioxide greenhouse effect and technical breakthroughs have resulted in a segment of the nuclear industry examining power reactor concepts with PRIME safety characteristics. PRIME is an acronym for Passive safety, Resilience, Inherent safety, Malevolence resistance, and Extended time after initiation of an accident for external help. The basic ideal of PRIME is to develop power reactors in which operator error, internal sabotage, or external assault do not cause a significant release of radioactivity to the environment. Several PRIME reactor concepts are being considered. In each case, an existing, proven power reactor technology is combined with radical innovations in selected plant components and in the safety philosophy. The Process Inherent Ultimate Safety (PIUS) reactor is a modified pressurized-water reactor, the Modular High Temperature Gas-Cooled Reactor (MHTGR) is a modified gas-cooled reactor, and the Advanced CANDU Project is a modified heavy-water reactor. In addition to the reactor concepts, there is parallel work on super containments. The objective is the development of a passive box'' that can contain radioactivity in the event of any type of accident. This report briefly examines: why a segment of the nuclear power community is taking this new direction, how it differs from earlier directions, and what technical options are being considered. A more detailed description of which countries and reactor vendors have undertaken activities follows. 41 refs.

  13. Dynamics and inherent safety features of small modular high temperature gas-cooled reactors

    SciTech Connect

    Harrington, R.M.; Ball, S.J.; Cleveland, J.C.

    1986-01-01

    Investigations were made at Oak Ridge National Laboratory to characterize the dynamics and inherent safety features of various modular high temperature gas-cooled reactor (HTGR) designs. This work was sponsored by the US Nuclear Regulatory Commission's HTGR Safety Research program. The US Department of Energy (DOE) and the Gas Cooled Reactor Associates (GCRA) have sponsored studies of several modular HTGR concepts, each having it own unique advantageous economic and inherent safety features. The DOE design team has recently choses a 350-MW(t) annular core with prismatic, graphite matrix fuel for its reference plant. The various safety features of this plant and of the pebble-bed core designs similar to those currently being developed and operated in the Federal Republic of Germany (FRG) are described. A varity of postulated accident sequences involving combinations of loss of forced circulation of the helium primary coolant, loss of primary coolant pressurization, and loss of normal and backup heat sinks were studied and are discussed. Results demonstrate that each concept can withstand an uncontrolled heatup accident without reaching excessive peak fuel temperatures. Comparisons of calculated and measured response for a loss of forced circulation test on the FRG reactor, AVR, are also presented. 10 refs.

  14. Inherent safety advantages of carbide fuel systems and technical issues regarding natural convection in LMRs

    SciTech Connect

    Barthold, W.P.

    1984-08-01

    The scope of work is to summarize inherent safety advantages that are unique to the use of a carbide based fuel system and to summarize the technical issues regarding natural convection flow in LMFBR cores. As discussed in this report, carbide fuel provides the designer with far greater flexibility than oxide fuel. Carbide fuel systems can be designed to eliminate major accident initiators. They turn quantitative advantages into a qualitative advantage. The author proposed to LANL a series of core design and component concepts that would greatly enhance the safety of carbide over oxide systems. This report cites a series of safety advantages which potentially exist for a carbide fuel system. Natural convection issues have not been given much attention in the past. Only during the last few years has this issue been addressed in some detail. Despite claims to the contrary by some of the LMR contractors, the author does not think that the natural convection phenomena is fully understood. Some of the approximations made in natural convection transient analyses have probably a greater impact on calculated transient temperatures than the effects under investigation. Only integral in-pile experimental data and single assembly out-of-pile detailed data are available for comparisons with analytical models and correlations. Especially for derated cores, the natural convection capability of a LMR should be far superior to that of a LWR. The author ranks the natural convection capability of the LMR as the most important inherent safety feature.

  15. A study of improved MHR 50/100 toward a higher level of inherent safety

    SciTech Connect

    Minatsuki, I.; Otani, T.; Shimizu, K.; Oyama, S.; Tsukamoto, H.; Kunitomi, K.

    2012-07-01

    A new concept of the Mitsubishi small-sized High temperature gas-cooled modular Reactors (MHR-50/100) had been developed and published in papers. The study results of the first design concept show that the MHR-50/100 can achieve the inherent safety level set as a design target in case of water ingress during steam generator tube rupture accident. And more specifically, the reactor was shown to remain stable during long-term station black out (SBO) with protection of only passive devices during a depressurization accident and with additional motion of steam dump system during a water ingress accident. Recently greater requirements for safety of future nuclear plants including the MHR-50/100 have been expected. This study has thus made a key design improvement for the MHR-50/100 in order to secure the inherent safety aspect without reliance on active steam dump system in case of a water ingress accident. The innovative technologies listed below have been created and investigated to achieve the improved MHR-50/100 design; (1) Design improvement of steam generator, (2) Heat balance optimization of steam cycle, (3) Control system design of differential pressure between primary helium gas and water/steam, (4) Study on operation procedure during a water ingress accident. (authors)

  16. Progress in reliability of fast reactor operation and new trends to increased inherent safety

    SciTech Connect

    Merk, Bruno; Stanculescu, Alexander; Chellapandi, Perumal; Hill, Robert

    2015-06-01

    The reasons for the renewed interest in fast reactors and an overview of the progress in sodium cooled fast reactor operation in the last ten years are given. The excellent operational performance of sodium cooled fast reactors in this period is highlighted as a sound basis for the development of new fast reactors. The operational performance of the BN-600 is compared and evaluated against the performance of German light water reactors to assess the reliability. The relevance of feedback effects for safe reactor design is described, and a new method for the enhancement of feedback effects in fast reactors is proposed. Experimental reactors demonstrating the inherent safety of advanced sodium cooled fast reactor designs are described and the potential safety improvements resulting from the use of fine distributed moderating material are discussed.

  17. Experimental and analytical study of loss-of-flow transients in EBR-II occurring at decay power levels

    SciTech Connect

    Chang, L.K.; Mohr, D.; Feldman, E.E.; Betten, P.R.; Planchon, H.P.

    1985-01-01

    A series of eight loss-of-flow (LOF) tests have been conducted in EBR-II to study the transition between forced and natural convective flows following a variety of loss-of-primary-pumping power conditions from decay heat levels. Comparisons of measurements and pretest/posttest predictions were made on a selected test. Good agreements between measurements and predictions was found prior to and just after the flow reaching its minimum, but the agreement is not as good after that point. The temperatures are consistent with the flow response and the assumed decay power. The measured results indicate that the flows of driver and the instrumented subassemblies are too much in the analytical model in the natural convective region. Although a parametric study on secondary flow, turbulent-laminar flow transition, heat transfer ability of the intermediate heat exchange at low flow and flow mixing in the primary tank has been performed to determine their effects on the flow, the cause of the discrepancy at very low flow level is still unknown.

  18. Microchemical and microstructural evolution of AISI 304 stainless steel irradiated in EBR-II at PWR-relevant dpa rates

    NASA Astrophysics Data System (ADS)

    Dong, Y.; Sencer, B. H.; Garner, F. A.; Marquis, E. A.

    2015-12-01

    AISI 304 stainless steel was irradiated at 416 °C and 450 °C at a 4.4 × 10-9 and 3.05 × 10-7 dpa/s to ∼0.4 and ∼28 dpa, respectively, in the reflector of the EBR-II fast reactor. Both unirradiated and irradiated conditions were examined using standard and scanning transmission electron microscopy, energy dispersive spectroscopy, and atom probe tomography on very small specimens produced by focused ion beam milling. These results are compared with previous electron microscopy examination of 3 mm disks from essentially the same material. By comparing a very low dose specimen with a much higher dose specimen, both derived from a single reactor assembly, it has been demonstrated that the coupled microstructural and microchemical evolution of dislocation loops and other sinks begins very early, with elemental segregation producing at these sinks what appears to be measurable precursors to fully formed precipitates found at higher doses. The nature of these sinks and their possible precursors are examined in detail.

  19. Estimation of Inherent Safety Margins in Loaded Commercial Spent Nuclear Fuel Casks

    DOE PAGESBeta

    Banerjee, Kaushik; Robb, Kevin R.; Radulescu, Georgeta; Scaglione, John M.

    2016-06-15

    We completed a novel assessment to determine the unquantified and uncredited safety margins (i.e., the difference between the licensing basis and as-loaded calculations) available in as-loaded spent nuclear fuel (SNF) casks. This assessment was performed as part of a broader effort to assess issues and uncertainties related to the continued safety of casks during extended storage and transportability following extended storage periods. Detailed analyses crediting the actual as-loaded cask inventory were performed for each of the casks at three decommissioned pressurized water reactor (PWR) sites to determine their characteristics relative to regulatory safety criteria for criticality, thermal, and shielding performance.more » These detailed analyses were performed in an automated fashion by employing a comprehensive and integrated data and analysis tool—Used Nuclear Fuel-Storage, Transportation & Disposal Analysis Resource and Data System (UNF-ST&DARDS). Calculated uncredited criticality margins from 0.07 to almost 0.30 Δkeff were observed; calculated decay heat margins ranged from 4 to almost 22 kW (as of 2014); and significant uncredited transportation dose rate margins were also observed. The results demonstrate that, at least for the casks analyzed here, significant uncredited safety margins are available that could potentially be used to compensate for SNF assembly and canister structural performance related uncertainties associated with long-term storage and subsequent transportation. The results also suggest that these inherent margins associated with how casks are loaded could support future changes in cask licensing to directly or indirectly credit the margins. Work continues to quantify the uncredited safety margins in the SNF casks loaded at other nuclear reactor sites.« less

  20. Radiation Damage Calculations for the FUBR and BEATRIX Irradiations of Lithium Compounds in EBR-II and FFTF

    SciTech Connect

    LR Greenwood

    1999-06-17

    The Fusion Breeder Reactor (FUBR) and Breeder Exchange Matrix (BEATRIX) experiments were cooperative efforts by members of the International Energy Agency to investigate the irradiation behavior of solid breeder materials for tritium production to support future fusion reactors. Lithium ceramic materials including Li{sub 2}O, LiAlO{sub 2}, Li{sub 4}SiO{sub 4}, and Li{sub 2}ZrO{sub 3} with varying {sup 6}Li enrichments from 0 to 95% were irradiated in a series of experiments in the Experimental Breeder Reactor (EBR II) and in the Fast Flux Test Facility (FFTF) over a period of about 10 years from 1982 to 1992. These experiments were characterized in terms of the nominal fast neutron fluences and measured {sup 6}Li burnup factors, as determined by either mass spectrometry or helium measurements. Radiation damage in these compounds is caused by both the {sup 6}Li-burnup reaction and by all other possible neutron reactions with the atoms in the compound materials. In this report, displacements per atom (dpa) values have been calculated for each type of material in each of the various irradiations that were conducted. Values up to 11% {sup 6}Li-burnup and 130 dpa are predicted for the longest irradiations. The dpa cross sections were calculated for each compound using the SPECOMP computer code. Details of the dpa calculations are presented in the report. Total dpa factors were determined with the SPECTER computer code by averaging the dpa cross sections over the measured or calculated neutron flux spectra for each series of irradiations. Using these new calculations, previously measured radiation damage effects in these lithium compounds can be compared or correlated with other irradiation data on the basis of the dpa factor as well as {sup 6}Li-burnup.

  1. Microstructural characterization and density change of 304 stainless steel reflector blocks after long-term irradiation in EBR-II

    NASA Astrophysics Data System (ADS)

    Huang, Y.; Wiezorek, J. M. K.; Garner, F. A.; Freyer, P. D.; Okita, T.; Sagisaka, M.; Isobe, Y.; Allen, T. R.

    2015-10-01

    While thin reactor structural components such as cladding and ducts do not experience significant gradients in dpa rate, gamma heating rate, temperature or stress, thick components can develop strong local variations in void swelling and irradiation creep in response to gradients in these variables. In this study we conducted microstructural investigations by transmission electron microscopy of two 52 mm thick 304-type stainless steel hex-blocks irradiated for 12 years in the EBR-II reactor with accumulated doses ranging from ∼0.4 to 33 dpa. Spatial variations in the populations of voids, precipitates, Frank loops and dislocation lines have been determined for 304 stainless steel sections exposed to different temperatures, different dpa levels and at different dpa rates, demonstrating the existence of spatial gradients in the resulting void swelling. The microstructural measurements compare very well with complementary density change measurements regarding void swelling gradients in the 304 stainless steel hex-block components. The TEM studies revealed that the original cold-worked-state microstructure of the unirradiated blocks was completely erased by irradiation, replaced by high densities of interstitial Frank loops, voids and carbide precipitates at both the lowest and highest doses. At large dose levels the amount of volumetric void swelling correlated directly with the gamma heating gradient-related temperature increase (e.g. for 28 dpa, ∼2% swelling at 418 °C and ∼2.9% swelling at 448 °C). Under approximately iso-thermal local conditions, volumetric void swelling was found to increase with dose level (e.g. ∼0.2% swelling at 0.4 dpa, ∼0.5% swelling at 4 dpa and ∼2% swelling at 28 dpa). Carbide precipitate formation levels were found to be relatively independent of both dpa level and temperature and induced a measurable densification. Void swelling was dominant at the higher dose levels and caused measurable decreases in density. Void swelling

  2. The dependence of helium generation rate on nickel content of Fe Cr Ni alloys irradiated to high dpa levels in EBR-II

    NASA Astrophysics Data System (ADS)

    Garner, F. A.; Oliver, B. M.; Greenwood, L. R.

    1998-10-01

    Fusion-relevant helium-effects experiments conducted on austenitic steels in the Materials Open Test Assembly (MOTA) of the Fast Flux Test Facility (FFTF) fast reactor had to recognize the contributions of both the high neutron energy (n,α) reactions and that of the 58Ni(n,γ) 59Ni(n,α) reaction sequence with low energy neutrons. An experiment conducted in the harder neutron spectra found within the core of Experimental Breeder Reactor-II (EBR-II) has shown that the helium in this reactor was generated almost exclusively from the interaction of high energy neutrons with the natural isotopes of nickel. There was very little contribution from 59Ni. The helium production was found to scale directly with the nickel content over the range 25-75% Ni. Even at very high neutron exposures, the helium production in such reactors can be predicted within 5% accuracy on the basis of high energy reactions, as demonstrated by an experiment conducted on three Fe-15Cr-Ni ternary alloys irradiated to doses of 75-131 dpa in EBR-II.

  3. Pyroprocessing of Oxidized Sodium-Bonded Fast Reactor Fuel -- an Experimental Study of Treatment Options for Degraded EBR-II Fuel

    SciTech Connect

    S. D. Herrmann; L. A. Wurth; N. J. Gese

    2013-09-01

    An experimental study was conducted to assess pyrochemical treatment options for degraded EBR-II fuel. As oxidized material, the degraded fuel would need to be converted back to metal to enable electrorefining within an existing electrometallurgical treatment process. A lithium-based electrolytic reduction process was studied to assess the efficacy of converting oxide materials to metal with a particular focus on the impact of zirconium oxide and sodium oxide on this process. Bench-scale electrolytic reduction experiments were performed in LiCl-Li2O at 650 °C with combinations of manganese oxide (used as a surrogate for uranium oxide), zirconium oxide, and sodium oxide. The experimental study illustrated how zirconium oxide and sodium oxide present different challenges to a lithium-based electrolytic reduction system for conversion of select metal oxides to metal.

  4. Characterization of degraded EBR-II fuel from the ICPP-603 basin: National spent nuclear fuel program, FY 1999 final report

    SciTech Connect

    Pahl, R. G.

    2000-04-17

    Characterization data is reported for sodium bonded Experimental Breeder Reactor II (EBR-II) fuel which had been stored underwater in containers since the late 1970's. Sixteen stainless steel storage containers were retrieved from the ICPP-603 storage pool at the Idaho National Engineering and Environmental Laboratory (INEEL) in Idaho. Ten of the containers had leaked water due to improper sealing. In the container chosen for detailed destructive analysis, the stainless steel cladding on the uranium alloy fuel had ruptured and fuel oxide particulate formed and filled the bottom of the container. Headspace gas analysis determined that greater than 99% hydrogen was present. Cesium-137, which had leached out of the fuel during the aqueous corrosion process, dominated the radionuclide source term of the water. The metallic sodium from the fuel element bond had reacted with the water, forming a caustic solution of NaOH.

  5. Safety assessment in plant layout design using indexing approach: implementing inherent safety perspective. Part 2-Domino Hazard Index and case study.

    PubMed

    Tugnoli, Alessandro; Khan, Faisal; Amyotte, Paul; Cozzani, Valerio

    2008-12-15

    The design of layout plans requires adequate assessment tools for the quantification of safety performance. The general focus of the present work is to introduce an inherent safety perspective at different points of the layout design process. In particular, index approaches for safety assessment and decision-making in the early stages of layout design are developed and discussed in this two-part contribution. Part 1 (accompanying paper) of the current work presents an integrated index approach for safety assessment of early plant layout. In the present paper (Part 2), an index for evaluation of the hazard related to the potential of domino effects is developed. The index considers the actual consequences of possible escalation scenarios and scores or ranks the subsequent accident propagation potential. The effects of inherent and passive protection measures are also assessed. The result is a rapid quantification of domino hazard potential that can provide substantial support for choices in the early stages of layout design. Additionally, a case study concerning selection among various layout options is presented and analyzed. The case study demonstrates the use and applicability of the indices developed in both parts of the current work and highlights the value of introducing inherent safety features early in layout design. PMID:18406517

  6. Pyroprocessing of oxidized sodium-bonded fast reactor fuel - An experimental study of treatment options for degraded EBR-II fuel

    SciTech Connect

    Hermann, S.D.; Gese, N.J.; Wurth, L.A.

    2013-07-01

    An experimental study was conducted to assess pyrochemical treatment options for degraded EBR-II fuel. As oxidized material, the degraded fuel would need to be converted back to metal to enable electrorefining within an existing electro-metallurgical treatment process. A lithium-based electrolytic reduction process was studied to assess the efficacy of converting oxide materials to metal with a particular focus on the impact of zirconium oxide and sodium oxide on this process. Bench-scale electrolytic reduction experiments were performed in LiCl-Li{sub 2}O at 650 C. degrees with combinations of manganese oxide (used as a surrogate for uranium oxide), zirconium oxide, and sodium oxide. In the absence of zirconium or sodium oxide, the electrolytic reduction of MnO showed nearly complete conversion to metal. The electrolytic reduction of a blend of MnO-ZrO{sub 2} in LiCl - 1 wt% Li{sub 2}O showed substantial reduction of manganese, but only 8.5% of the zirconium was found in the metal phase. The electrolytic reduction of the same blend of MnO-ZrO{sub 2} in LiCl - 1 wt% Li{sub 2}O - 6.2 wt% Na{sub 2}O showed substantial reduction of manganese, but zirconium reduction was even less at 2.4%. This study concluded that ZrO{sub 2} cannot be substantially reduced to metal in an electrolytic reduction system with LiCl - 1 wt% Li{sub 2}O at 650 C. degrees due to the perceived preferential formation of lithium zirconate. This study also identified a possible interference that sodium oxide may have on the same system by introducing a parasitic and cyclic reaction of dissolved sodium metal between oxidation at the anode and reduction at the cathode. When applied to oxidized sodium-bonded EBR-II fuel (e.g., U-10Zr), the prescribed electrolytic reduction system would not be expected to substantially reduce zirconium oxide, and the accumulation of sodium in the electrolyte could interfere with the reduction of uranium oxide, or at least render it less efficient.

  7. Inherent Risk or Risky Decision? Coach's Failure to Use Safety Device an Assumed Risk

    ERIC Educational Resources Information Center

    Dodds, Mark A.; Bochicchio, Kristi Schoepfer

    2013-01-01

    The court examined whether a coach's failure to implement a safety device during pitching practice enhanced the risk to the athlete or resulted in a suboptimal playing condition, in the context of the assumption of risk doctrine.

  8. Proposed and existing passive and inherent safety-related structures, systems, and components (building blocks) for advanced light-water reactors

    SciTech Connect

    Forsberg, C.W.; Moses, D.L.; Lewis, E.B.; Gibson, R.; Pearson, R.; Reich, W.J.; Murphy, G.A.; Staunton, R.H.; Kohn, W.E.

    1989-10-01

    A nuclear power plant is composed of many structures, systems, and components (SSCs). Examples include emergency core cooling systems, feedwater systems, and electrical systems. The design of a reactor consists of combining various SSCs (building blocks) into an integrated plant design. A new reactor design is the result of combining old SSCs in new ways or use of new SSCs. This report identifies, describes, and characterizes SSCs with passive and inherent features that can be used to assure safety in light-water reactors. Existing, proposed, and speculative technologies are described. The following approaches were used to identify the technologies: world technical literature searches, world patent searches, and discussions with universities, national laboratories and industrial vendors. 214 refs., 105 figs., 26 tabs.

  9. Experimental and design experience with passive safety features of liquid metal reactors

    SciTech Connect

    Lucoff, D.M.; Waltar, A.E.; Sackett, J.I.; Salvatores, M.; Aizawa, K.

    1992-10-01

    Liquid metal cooled reactors (LMRs) have already been demonstrated to be robust machines. Many reactor designers now believe that it is possible to include in this technology sufficient passive safety that LMRs would be able to survive loss of flow, loss of heat sink, and transient overpower events, even if the plant protective system fails completely and do so without damage to the core. Early whole-core testing in Rapsodie, EBR-II. and FFTF indicate such designs may be possible. The operational safety testing program in EBR-II is demonstrating benign response of the reactor to a full range of controls failures. But additional testing is needed if transient core structural response under major accident conditions is to be properly understood. The proposed international Phase IIB passive safety tests in FFTF, being designed with a particular emphasis on providing, data to understand core bowing extremes, and further tests planned in EBR-II with processed IFR fuel should provide a substantial and unique database for validating the computer codes being used to simulate postulated accident conditions.

  10. Experimental and design experience with passive safety features of liquid metal reactors

    SciTech Connect

    Lucoff, D.M.; Waltar, A.E. ); Sackett, J.I. ); Aizawa, K. )

    1992-07-01

    Liquid metal cooled reactors (LMRs) have already been demonstrated to be robust machines. Many reactor designers now believe that it is possible to include in this technology sufficient passive safety that LMRs would be able to survive loss of flow, loss of heat sink, and transient overpower events, even if the plant protective system fails completely--and do so without damage to the core. Early whole-core testing in Rapsodie, EBR-II, and FFTF indicate such designs may be possible. The operational safety testing program in EBR-II is demonstrating benign response of the reactor to a full range on controls failures. But additional testing is needed if transient core structural response under major accident conditions is to be properly understood. The proposed international Phase IIB passive safety tests in FFTF, being designed with a particular emphasis on providing data to understand core bowing extremes, and further tests planned in EBR-II with processed IFR fuel should provide a substantial and unique database for validating the computer codes being used to simulate postulated accident conditions.

  11. Safety issues of dry fuel storage at RSWF

    SciTech Connect

    Clarksean, R.L.; Zahn, T.P.

    1995-02-01

    Safety issues associated with the dry storage of EBR-II spent fuel are presented and discussed. The containers for the fuel have been designed to prevent a leak of fission gases to the environment. The storage system has four barriers for the fission gases. These barriers are the fuel cladding, an inner container, an outer container, and the liner at the RSWF. Analysis has shown that the probability of a leak to the environment is much less than 10{sup {minus}6} per year, indicating that such an event is not considered credible. A drop accident, excessive thermal loads, criticality, and possible failure modes of the containers are also addressed.

  12. Inherent Stability of Helicopters

    NASA Technical Reports Server (NTRS)

    Crocco, G Arturo

    1923-01-01

    The equilibrium, in still air, of a "stationary" helicopter (i.e., of one having neither vertical nor translational velocity, but a tendency to remain practically motionless within restricted limits of space) presents some difficulty in practice and justifies a theoretical investigation of its "inherent stability," i.e., independent of the pilot.

  13. Safety aspects of the IFR pyroprocess fuel cycle

    SciTech Connect

    Forrester, R.J.; Lineberry, M.J.; Charak, I.; Tessier, J.H.; Solbrig, C.W.; Gabor, J.D.

    1989-01-01

    This paper addresses the important safety considerations related to the unique Integral Fast Reactor (IFR) fuel cycle technology, the pyroprocess. Argonne has been developing the IFR since 1984. It is a liquid metal cooled reactor, with a unique metal alloy fuel, and it utilizes a radically new fuel cycle. An existing facility, the Hot Fuel Examination Facility-South (HFEF/S) is being modified and equipped to provide a complete demonstration of the fuel cycle. This paper will concentrate on safety aspects of the future HFEF/S operation, slated to begin late next year. HFEF/S is part of Argonne's complex of reactor test facilities located on the Idaho National Engineering Laboratory. HFEF/S was originally put into operation in 1964 as the EBR-II Fuel Cycle Facility (FCF) (Stevenson, 1987). From 1964--69 FCF operated to demonstrate an earlier and incomplete form of today's pyroprocess, recycling some 400 fuel assemblies back to EBR-II. The FCF mission was then changed to one of an irradiated fuels and materials examination facility, hence the name change to HFEF/S. The modifications consist of activities to bring the facility into conformance with today's much more stringent safety standards, and, of course, providing the new process equipment. The pyroprocess and the modifications themselves are described more fully elsewhere (Lineberry, 1987; Chang, 1987). 18 refs., 5 figs., 2 tabs.

  14. BOUNDED MINIMUM INHERENT AVAILABILITY REQUIREMENTS FOR THE SYSTEM DESCRIPTION DOCUMENTS

    SciTech Connect

    L. Booth

    1998-03-13

    The purpose of this analysis is to establish bounded minimum inherent availability requirements for the Mined Geologic Disposal System (MGDS) System Description Documents (SDDs). The purpose of the bounded minimum inherent availability is to provide a lower bound on availability which will allow design to meet throughput requirements while not affecting the ability of the items to perform their intended safety function.

  15. Final report-passive safety optimization in liquid sodium-cooled reactors.

    SciTech Connect

    Cahalana, J. E.; Hahn, D.; Nuclear Engineering Division; Korea Atomic Energy Research Inst.

    2007-08-13

    This report summarizes the results of a three-year collaboration between Argonne National Laboratory (ANL) and the Korea Atomic Energy Research Institute (KAERI) to identify and quantify the performance of innovative design features in metallic-fueled, sodium-cooled fast reactor designs. The objective of the work was to establish the reliability and safety margin enhancements provided by design innovations offering significant potential for construction, maintenance, and operating cost reductions. The project goal was accomplished with a combination of advanced model development (Task 1), analysis of innovative design and safety features (Tasks 2 and 3), and planning of key safety experiments (Task 4). Task 1--Computational Methods for Analysis of Passive Safety Design Features: An advanced three-dimensional subassembly thermal-hydraulic model was developed jointly and implemented in ANL and KAERI computer codes. The objective of the model development effort was to provide a high-accuracy capability to predict fuel, cladding, coolant, and structural temperatures in reactor fuel subassemblies, and thereby reduce the uncertainties associated with lower fidelity models previously used for safety and design analysis. The project included model formulation, implementation, and verification by application to available reactor tests performed at EBR-II. Task 2--Comparative Analysis and Evaluation of Innovative Design Features: Integrated safety assessments of innovative liquid metal reactor designs were performed to quantify the performance of inherent safety features. The objective of the analysis effort was to identify the potential safety margin enhancements possible in a sodium-cooled, metal-fueled reactor design by use of passive safety mechanisms to mitigate low-probability accident consequences. The project included baseline analyses using state-of-the-art computational models and advanced analyses using the new model developed in Task 1. Task 3--Safety

  16. Adaptive robust control of the EBR-II reactor

    SciTech Connect

    Power, M.A.; Edwards, R.M.

    1996-05-01

    Simulation results are presented for an adaptive H{sub {infinity}} controller, a fixed H{sub {infinity}} controller, and a classical controller. The controllers are applied to a simulation of the Experimental Breeder Reactor II primary system. The controllers are tested for the best robustness and performance by step-changing the demanded reactor power and by varying the combined uncertainty in initial reactor power and control rod worth. The adaptive H{sub {infinity}} controller shows the fastest settling time, fastest rise time and smallest peak overshoot when compared to the fixed H{sub {infinity}} and classical controllers. This makes for a superior and more robust controller.

  17. JAEA Fatigue Analysis of EBR-II Duplex Tubing

    SciTech Connect

    J. H. Jackson; D. L. Porter; W. R. Lloyd

    2009-07-01

    This work addresses questions brought up concerning the mechanisms associated with fatigue crack growth retardation and/or arrest within the nickel bond layer in duplex 2¼ Cr-1Mo steel superheater tubes. Previous work performed at the Idaho National Laboratory (INL) indicated that the nickel bond layer did not function as a crack arrestor during fatigue crack propagation with the exception of one, isolated case involving an exceptionally low fatigue load and a high temperature (400 0C) environment. Since it is atypical for a fatigue crack to propagate from a relatively soft material (the nickel bond layer) to a harder material (the 2¼ Cr-1Mo steel) there has been speculation that the nickel bond layer was hardened in service. Additionally, there are questions surrounding the nature of the fatigue crack propagation within the nickel bond layer; specifically with regard to the presence of voids seen on micrographs of the bond layer and oxidation within the steel along the edge of the nickel bond layer. There is uncertainty as to the effect of these voids and/or oxide barriers with respect to potential fatigue crack arrest.

  18. Concept of an inherently-safe high temperature gas-cooled reactor

    SciTech Connect

    Ohashi, Hirofumi; Sato, Hiroyuki; Tachibana, Yukio; Kunitomi, Kazuhiko; Ogawa, Masuro

    2012-06-06

    As the challenge to ensure no harmful release of radioactive materials at the accidents by deterministic approach instead to satisfy acceptance criteria or safety goal for risk by probabilistic approach, new concept of advanced reactor, an inherently-safe high temperature gas-cooled reactor, is proposed based on the experience of the operation of the actual High Temperature Gas-cooled Reactor (HTGR) in Japan, High Temperature Engineering Test Reactor (HTTR), and the design of the commercial plant (GTHTR300), utilizing the inherent safety features of the HTGR (i.e., safety features based on physical phenomena). The safety design philosophy of the inherently-safe HTGR for the safety analysis of the radiological consequences is determined as the confinement of radioactive materials is assured by only inherent safety features without engineered safety features, AC power or prompt actions by plant personnel if the design extension conditions occur. Inherent safety features to prevent the loss or degradation of the confinement function are identified. It is proposed not to apply the probabilistic approach for the evaluation of the radiological consequences of the accidents in the safety analysis because no inherent safety features fail for the mitigation of the consequences of the accidents. Consequently, there are no event sequences to harmful release of radioactive materials if the design extension conditions occur in the inherently-safe HTGR concept. The concept and future R and D items for the inherently-safe HTGR are described in this paper.

  19. Principles of providing inherent self-protection and passive safety characteristics of the SVBR-75/100 type modular reactor installation for nuclear power plants of different capacity and purpose

    SciTech Connect

    Toshinsky, G.I.; Komlev, O.G.; Novikova, N.N.; Tormyshev, I.V.; Stepanov, V.S.; Klimov, N.N.; Dedoul, A.V.

    2007-07-01

    The report presents a brief description of the reactor installation SVBR-75/100, states a concept of providing the RI safety and presents the basic results of the analysis of the most dangerous pre-accidental situations and beyond the design basis accidents, which have been obtained in the process of validating the RI safety. It has been shown that the safety functions concerning the accidental shutdown of the reactor, total blacking out of the NPP and localization of the accidental situation relating to the postulated simultaneous rupture of several steam-generator tubes are not subject to influence of the human factor and are entirely realized in a passive way. (authors)

  20. 16 CFR 1211.7 - Inherent entrapment protection requirements.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... ACT REGULATIONS SAFETY STANDARD FOR AUTOMATIC RESIDENTIAL GARAGE DOOR OPERATORS The Standard § 1211.7 Inherent entrapment protection requirements. (a)(1) Other than for the first 1 foot (305mm) of door travel... functional, the operator of a downward moving residential garage door shall initiate reversal of the...

  1. 16 CFR 1211.7 - Inherent entrapment protection requirements.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... ACT REGULATIONS SAFETY STANDARD FOR AUTOMATIC RESIDENTIAL GARAGE DOOR OPERATORS The Standard § 1211.7 Inherent entrapment protection requirements. (a)(1) Other than for the first 1 foot (305mm) of door travel... functional, the operator of a downward moving residential garage door shall initiate reversal of the...

  2. 16 CFR 1211.7 - Inherent entrapment protection requirements.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... ACT REGULATIONS SAFETY STANDARD FOR AUTOMATIC RESIDENTIAL GARAGE DOOR OPERATORS The Standard § 1211.7 Inherent entrapment protection requirements. (a)(1) Other than for the first 1 foot (305mm) of door travel... functional, the operator of a downward moving residential garage door shall initiate reversal of the...

  3. Inherently safe reactors and a second nuclear era.

    PubMed

    Weinberg, A M; Spiewak, I

    1984-06-29

    The Swedish PIUS reactor and the German-American small modular high-temperature gas-cooled reactor are inherently safe-that is, their safety relies not upon intervention of humans or of electromechanical devices but on immutable principles of physics and chemistry. A second nuclear era may require commercialization and deployment of such inherently safe reactors, even though existing light-water reactors appear to be as safe as other well-accepted sources of central electricity, particularly hydroelectric dams. PMID:17793362

  4. Inherent Conservatism in Deterministic Quasi-Static Structural Analysis

    NASA Technical Reports Server (NTRS)

    Verderaime, V.

    1997-01-01

    The cause of the long-suspected excessive conservatism in the prevailing structural deterministic safety factor has been identified as an inherent violation of the error propagation laws when reducing statistical data to deterministic values and then combining them algebraically through successive structural computational processes. These errors are restricted to the applied stress computations, and because mean and variations of the tolerance limit format are added, the errors are positive, serially cumulative, and excessively conservative. Reliability methods circumvent these errors and provide more efficient and uniform safe structures. The document is a tutorial on the deficiencies and nature of the current safety factor and of its improvement and transition to absolute reliability.

  5. Nuclear energy with inherent safety: Change of outdated paradigm, criteria

    NASA Astrophysics Data System (ADS)

    Adamov, E. O.; Orlov, V. V.; Rachkov, V. I.; Slessarev, I. S.; Khomyakov, Yu. S.

    2015-12-01

    Modern nuclear power technology still has significant sources of risk, and, weak links, such as, a threat of severe accidents with catastrophic unpredictable consequences and damage to the population, proliferation of nuclear weapon-usable materials, risks of long-term storage of toxic radioactive waste, risks of loss of major investments in nuclear facilities and their construction, lack of fuel resources for the ambitious role of nuclear power in the competitive balance of energy. Each of these risks is important and almost independent, though the elimination of some of them does not significantly alter the overall assessment of nuclear power.

  6. Inherent safety of minimum-burnup breed and burn reactors

    SciTech Connect

    Qvist, S.; Reenspan, E.

    2012-07-01

    Reactors that aim to sustain the breed and burn (B and B) mode of operation at minimum discharge burnup require excellent neutron economy, Minimum-burnup B and B cores are generally large and feature low neutron leakage probability and a hard neutron spectrum. While highly promising fuel cycles can be achieved with such designs, the very same features are pushing the limits of the core's ability to passively respond safely to unprotected accidents. Low leakage minimum-burnup sodium-cooled B and B cores have a large positive coolant void-worth and coolant temperature reactivity coefficient. In this study, the applicability of major approaches for fast reactor void-worth reduction is evaluated specifically for B and B cores. The design, shuffling scheme and performance of a new metallic-fueled, sodium-cooled minimum burnup B and B core, used as basis for the void-worth reduction analysis, is presented. The analysis shows that reactivity control systems based on passive {sup 6}Li injection during temperature excursions are the only option able to provide negative void-worth without significantly increasing the minimum burnup required for sustaining the B and B mode of operation. A new type of lithium expansion module (LEM) system was developed specifically for B and B cores and its effect on core performance is presented. (authors)

  7. Boiling water neutronic reactor incorporating a process inherent safety design

    DOEpatents

    Forsberg, C.W.

    1985-02-19

    A boiling-water reactor core is positioned within a prestressed concrete reactor vessel of a size which will hold a supply of coolant water sufficient to submerge and cool the reactor core by boiling for a period of at least one week after shutdown. Separate volumes of hot, clean (nonborated) water for cooling during normal operation and cool highly borated water for emergency cooling and reactor shutdown are separated by an insulated wall during normal reactor operation with contact between the two water volumes being maintained at interfaces near the top and bottom ends of the reactor vessel. Means are provided for balancing the pressure of the two water volumes at the lower interface zone during normal operation to prevent entry of the cool borated water into the reactor core region, for detecting the onset of excessive power to coolant flow conditions in the reactor core and for detecting low water levels of reactor coolant. Cool borated water is permitted to flow into the reactor core when low reactor coolant levels or excessive power to coolant flow conditions are encountered.

  8. Boiling water neutronic reactor incorporating a process inherent safety design

    DOEpatents

    Forsberg, Charles W.

    1987-01-01

    A boiling-water reactor core is positioned within a prestressed concrete reactor vessel of a size which will hold a supply of coolant water sufficient to submerge and cool the reactor core by boiling for a period of at least one week after shutdown. Separate volumes of hot, clean (non-borated) water for cooling during normal operation and cool highly borated water for emergency cooling and reactor shutdown are separated by an insulated wall during normal reactor operation with contact between the two water volumes being maintained at interfaces near the top and bottom ends of the reactor vessel. Means are provided for balancing the pressure of the two volumes at the lower interface zone during normal operation to prevent entry of the cool borated water into the reactor core region, for detecting the onset of excessive power to coolant flow conditions in the reactor core and for detecting low water levels of reactor coolant. Cool borated water is permitted to flow into the reactor core when low reactor coolant levels or excessive power to coolant flow conditions are encountered.

  9. Harnessing Collective Knowledge Inherent in Tag Clouds

    ERIC Educational Resources Information Center

    Cress, U.; Held, C.

    2013-01-01

    Tagging systems represent the conceptual knowledge of a community. We experimentally tested whether people harness this collective knowledge when navigating through the Web. As a within-factor we manipulated people's prior knowledge (no knowledge vs. prior knowledge that was congruent/incongruent to the collective knowledge inherent in the tags).…

  10. Critical Social Theory: Core Tenets, Inherent Issues

    ERIC Educational Resources Information Center

    Freeman, Melissa; Vasconcelos, Erika Franca S.

    2010-01-01

    This chapter outlines the core tenets of critical social theory and describes inherent issues facing evaluators conducting critical theory evaluation. Using critical pedagogy as an example, the authors describe the issues facing evaluators by developing four of the subtheories that comprise a critical social theory: (a) a theory of false…

  11. Inherent freeze protection for solar water heaters

    SciTech Connect

    Jeter, S.M.; Leonaitis, L.L.; Leonaitis, L.L.

    1981-05-01

    Research and development of a method for protection of a solar collector from freezing is described. The method is shown to be technically and economically feasible. A prototype water heating system using the inherent freeze protection method was successfully operated during the winter of 1980 to 1981.

  12. Safety.

    ERIC Educational Resources Information Center

    Education in Science, 1996

    1996-01-01

    Discusses safety issues in science, including: allergic reactions to peanuts used in experiments; explosions in lead/acid batteries; and inspection of pressure vessels, such as pressure cookers or model steam engines. (MKR)

  13. Inherently Tunable Electrostatic Assembly of Membrane Proteins

    SciTech Connect

    Liang, H.; Whited, G.; Nguyen, C.; Okerlund, A.; Stucky, G.D.

    2009-05-19

    Membrane proteins are a class of nanoscopic entities that control the matter, energy, and information transport across cellular boundaries. Electrostatic interactions are shown to direct the rapid co-assembly of proteorhodopsin (PR) and lipids into long-range crystalline arrays. The roles of inherent charge variations on lipid membranes and PR variants with different compositions are examined by tuning recombinant PR variants with different extramembrane domain sizes and charged amino acid substitutions, lipid membrane compositions, and lipid-to-PR stoichiometric ratios. Rational control of this predominantly electrostatic assembly for PR crystallization is demonstrated, and the same principles should be applicable to the assembly and crystallization of other integral membrane proteins.

  14. Apparent subdiffusion inherent to single particle tracking.

    PubMed Central

    Martin, Douglas S; Forstner, Martin B; Käs, Josef A

    2002-01-01

    Subdiffusion and its causes in both in vivo and in vitro lipid membranes have become the focus of recent research. We report apparent subdiffusion, observed via single particle tracking (SPT), in a homogeneous system that only allows normal diffusion (a DMPC monolayer in the fluid state). The apparent subdiffusion arises from slight errors in finding the actual particle position due to noise inherent in all experimental SPT systems. A model is presented that corrects this artifact, and predicts the time scales after which the effect becomes negligible. The techniques and results presented in this paper should be of use in all SPT experiments studying normal and anomalous diffusion. PMID:12324428

  15. Apparent subdiffusion inherent to single particle tracking.

    PubMed

    Martin, Douglas S; Forstner, Martin B; Käs, Josef A

    2002-10-01

    Subdiffusion and its causes in both in vivo and in vitro lipid membranes have become the focus of recent research. We report apparent subdiffusion, observed via single particle tracking (SPT), in a homogeneous system that only allows normal diffusion (a DMPC monolayer in the fluid state). The apparent subdiffusion arises from slight errors in finding the actual particle position due to noise inherent in all experimental SPT systems. A model is presented that corrects this artifact, and predicts the time scales after which the effect becomes negligible. The techniques and results presented in this paper should be of use in all SPT experiments studying normal and anomalous diffusion. PMID:12324428

  16. Inherent contradictions in the ego ideal.

    PubMed

    Dendy, Errol B

    2010-10-01

    The author puts forth a concept of the ego ideal as the fantasied self that the child believes will bring it gratification and happiness. He then shows how the ego ideal's content evolves through the various stages of psychosexual development in accordance with its mission. A picture emerges of an ego ideal in inherent conflict because it is shaped by contradictory wishes, as well as contradictory fantasies of how to make those wishes come true. A section on romantic love points to a second contradiction within the ego ideal, beyond its contradictory content: a contradiction of aim. PMID:21141785

  17. Inherently Chiral Spider-Like Oligothiophenes.

    PubMed

    Sannicolò, Francesco; Mussini, Patrizia R; Benincori, Tiziana; Martinazzo, Rocco; Arnaboldi, Serena; Appoloni, Giulio; Panigati, Monica; Quartapelle Procopio, Elsa; Marino, Valentina; Cirilli, Roberto; Casolo, Simone; Kutner, Wlodzimierz; Noworyta, Krzysztof; Pietrzyk-Le, Agnieszka; Iskierko, Zofia; Bartold, Katarzyna

    2016-07-25

    The racemate of an inherently chiral "spider-like" octathiophene monomer T83 , in which chirality is generated by torsion in its backbone, was synthesized. The racemate was resolved into configurationally stable antipodes by HPLC on a chiral stationary phase. Electrooxidation of the enantiomers resulted in materials displaying high enantiorecognition ability towards the antipodes of some chiral probes. Moreover, the T83 racemate demonstrated great aptitude to stimulate formation of 3D rigid architectures if used as a cross-linking monomer for molecular imprinting. This feature was exploited to devise a molecularly imprinted polymer-based chemosensor selective for a thymine-adenine oligonucleotide. PMID:27321902

  18. Inherently safe in situ uranium recovery.

    SciTech Connect

    Krumhansl, James Lee; Beauheim, Richard Louis; Brady, Patrick Vane; Arnold, Bill Walter; Kanney, Joseph F.; McKenna, Sean Andrew

    2009-05-01

    Expansion of uranium mining in the United States is a concern to some environmental groups and sovereign Native American Nations. An approach which may alleviate some problems is to develop inherently safe in situ uranium recovery ('ISR') technologies. Current ISR technology relies on chemical extraction of trace levels of uranium from aquifers that, once mined, can still contain dissolved uranium and other trace metals that are a health concern. Existing ISR operations are few in number; however, high uranium prices are driving the industry to consider expanding operations nation-wide. Environmental concerns and enforcement of the new 30 ppb uranium drinking water standard may make opening new mining operations more difficult and costly. Here we propose a technological fix: the development of inherently safe in situ recovery (ISISR) methods. The four central features of an ISISR approach are: (1) New 'green' leachants that break down predictably in the subsurface, leaving uranium, and associated trace metals, in an immobile form; (2) Post-leachant uranium/metals-immobilizing washes that provide a backup decontamination process; (3) An optimized well-field design that increases uranium recovery efficiency and minimizes excursions of contaminated water; and (4) A combined hydrologic/geochemical protocol for designing low-cost post-extraction long-term monitoring. ISISR would bring larger amounts of uranium to the surface, leave fewer toxic metals in the aquifer, and cost less to monitor safely - thus providing a 'win-win-win' solution to all stakeholders.

  19. Photoreponsive Hybrid Nanoparticles with Inherent FRET Activity.

    PubMed

    Achilleos, Demetra S; Hatton, T Alan; Vamvakaki, Maria

    2016-06-14

    The photoactivated inherent fluorescence resonance energy transfer (FRET) properties of a hard-and-soft hybrid nanosystem comprising poly(1'-(2-methacryloxyethyl)-3',3'-dimethyl-6-nitrospiro-(2H-1-benzopyran-2,2'-indoline))-co-poly[2-(dimethylamino)ethyl methacrylate] (PSPMA-co-PDMAEMA) random copolymer brushes on silica nanoparticles are described. This unique FRET process is switched on by the simultaneous generation of isomer X and merocyanine (MC), which are bipolar in nature and comprise donor-acceptor dyads, from a single spiropyran (SP) chromophore upon UV irradiation. These X-MC species exhibit sufficient lifetimes to allow the read-out of the FRET process. The phenomenon is gradually switched off because of the thermal relaxation of the bipolar chromophores. This inherent property of the nanoemitters is employed in the development of biosensors of high specificity by monitoring variations in the FRET efficiency and lifetime of the hybrids in the presence of biological substances. More specifically, bovine serum albumin (BSA) augments the formation of MC species and retards the MC photobleaching process, leading to the enhancement of the FRET efficiency and lifetime, respectively. On the other hand, amino acid l-histidine further retards the MC thermal relaxation and prolongs the FRET process. We envisage that this platform opens new perspectives in the development of novel, optical nanosensors for applications in various fields including healthcare products and environmental monitoring. PMID:27222922

  20. Inherent emotional quality of human speech sounds

    PubMed Central

    Myers-Schulz, Blake; Pujara, Maia; Wolf, Richard C.; Koenigs, Michael

    2012-01-01

    During much of the past century, it was widely believed that phonemes—the human speech sounds that constitute words—have no inherent semantic meaning, and that the relationship between a combination of phonemes (a word) and its referent is simply arbitrary. Although recent work has challenged this picture by revealing psychological associations between certain phonemes and particular semantic contents, the precise mechanisms underlying these associations have not been fully elucidated. Here we provide novel evidence that certain phonemes have an inherent, non-arbitrary emotional quality. Moreover, we show that the perceived emotional valence of certain phoneme combinations depends on a specific acoustic feature—namely, the dynamic shift within the phonemes' first two frequency components. These data suggest a phoneme-relevant acoustic property influencing the communication of emotion in humans, and provide further evidence against previously held assumptions regarding the structure of human language. This finding has potential applications for a variety of social, educational, clinical, and marketing contexts. PMID:23286242

  1. Human organ markets and inherent human dignity.

    PubMed

    MacKellar, Calum

    2014-01-01

    It has been suggested that human organs should be bought and sold on a regulated market as any other material property belongingto an individual. This would have the advantage of both addressing the grave shortage of organs available for transplantation and respecting the freedom of individuals to choose to do whatever they want with their body parts. The old arguments against such a market in human organs are, therefore, being brought back into question. The article examines the different arguments both in favour and against the sale of human organs. It concludes that the body and any of its elements is a full expression of the whole person. As such, they cannot have a price if the individual is to retain his or her full inherent dignity and if society is to retain and protect this very important concept. PMID:24979876

  2. Magnetic latch trigger for inherent shutdown assembly

    DOEpatents

    Sowa, Edmund S.

    1976-01-01

    An inherent shutdown assembly for a nuclear reactor is provided. A neutron absorber is held ready to be inserted into the reactor core by a magnetic latch. The latch includes a magnet whose lines of force are linked by a yoke of material whose Curie point is at the critical temperature of the reactor at which the neutron absorber is to be inserted into the reactor core. The yoke is in contact with the core coolant or fissionable material so that when the coolant or the fissionable material increase in temperature above the Curie point the yoke loses its magnetic susceptibility and the magnetic link is broken, thereby causing the absorber to be released into the reactor core.

  3. Inherently safe in situ uranium recovery

    DOEpatents

    Krumhansl, James L; Brady, Patrick V

    2014-04-29

    An in situ recovery of uranium operation involves circulating reactive fluids through an underground uranium deposit. These fluids contain chemicals that dissolve the uranium ore. Uranium is recovered from the fluids after they are pumped back to the surface. Chemicals used to accomplish this include complexing agents that are organic, readily degradable, and/or have a predictable lifetime in an aquifer. Efficiency is increased through development of organic agents targeted to complexing tetravalent uranium rather than hexavalent uranium. The operation provides for in situ immobilization of some oxy-anion pollutants under oxidizing conditions as well as reducing conditions. The operation also artificially reestablishes reducing conditions on the aquifer after uranium recovery is completed. With the ability to have the impacted aquifer reliably remediated, the uranium recovery operation can be considered inherently safe.

  4. Microfabricated mechanical biosensor with inherently differential readout

    NASA Astrophysics Data System (ADS)

    Savran, C. A.; Burg, T. P.; Fritz, J.; Manalis, S. R.

    2003-08-01

    We report measurements with a micromachined mechanical biosensor that inherently suppresses background effects by producing a differential signal with respect to a reference. The sensor comprises two adjacent cantilevers with interdigitated fingers between them that allow interferometric detection of the differential, i.e., relative bending. We demonstrate that differential detection can efficiently suppress unspecific chemical effects that result in cantilever bending. We show that the differential deflection noise is up to an order of magnitude lower than the absolute deflection noise in the low-frequency range of 0.0003-1 Hz, where many types of biologically relevant reactions occur. We also demonstrate the sensor's applicability to biological receptor-ligand systems by reporting experimental results on direct differential detection of biotin-streptavidin binding.

  5. Sensors and actuators inherent in biological species

    NASA Astrophysics Data System (ADS)

    Taya, Minoru; Stahlberg, Rainer; Li, Fanghong; Zhao, Ying Joyce

    2007-04-01

    This paper addresses examples of sensing and active mechanisms inherent in some biological species where both plants and animals cases are discussed: mechanosensors and actuators in Venus Fly Trap and cucumber tendrils, chemosensors in insects, two cases of interactions between different kingdoms, (i) cotton plant smart defense system and (ii) bird-of-paradise flower and hamming bird interaction. All these cases lead us to recognize how energy-efficient and flexible the biological sensors and actuators are. This review reveals the importance of integration of sensing and actuation functions into an autonomous system if we make biomimetic design of a set of new autonomous systems which can sense and actuate under a number of different stimuli and threats.

  6. Development of an inherently digital transducer

    NASA Technical Reports Server (NTRS)

    Richard, R. R.

    1972-01-01

    The term digital transducer normally implies the combination of conventional analog sensors with encoders or analog-to-digital converters. Because of the objectionable characteristics of most digital transducers, a program was instituted to investigate the possibility of producing a transducer that is inherently digital, instead of a transducer that is digital in the usual sense. Such a device would have improved accuracy and reliability and would have reduced power and bulk requirements because two processes, sensing and conditioning, would be combined into one processes. A Curie-point-temperature sensor is described that represents realization of the stated goal. Also, a metal-insulator semiconductor is described that does not conform precisely to the program goals but that appears to have applications as a new and interesting transduction device.

  7. Probabilities of inherent shutdown of unprotected events in innovative liquid metal reactors

    SciTech Connect

    Mueller, C.J.; Wade, D.C.

    1988-01-01

    The uncertainty in predicting the effectiveness of inherent shutdown in innovative liquid metal cooled reactors with metallic fuel results from three broad contributing areas of uncertainty: (1) the inability to exactly predict the frequency of ATWS events with potential to challenge the safety systems and require inherent shutdown; (2) the approximation of representing all such events by a selected set of ''generic scenarios''; and (3) the inability to exactly calculate the core response to the selected generic scenarios. This paper discusses the work being done to address each of these contributing areas, identifies the design and research approaches being used at Argonne National Laboratory to reducing the key contributions to uncertainties in inherent shutdown, and presents results. The conditional probabilities (given ATWS initiation) of achieving temperatures capable of defeating inherent shutdown are shown to range from /approximately/0.1% to negligible for current designs.

  8. 16 CFR 1211.13 - Inherent force activated secondary door sensors.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... sensors. 1211.13 Section 1211.13 Commercial Practices CONSUMER PRODUCT SAFETY COMMISSION CONSUMER PRODUCT... § 1211.13 Inherent force activated secondary door sensors. (a) Normal operation test. (1) A force activated door sensor of a door system installed according to the installation instructions shall...

  9. Why electronic mail is inherently private

    SciTech Connect

    Granger, S.

    1994-12-31

    Electronic Mail originated in Large-Area Networks and computer Bulletin Board Systems. On LAN`s in offices, it served the purpose of replacing office memos to make work more efficient. On BBS`s, it became a personal way of sending notes back and forth between acquaintances and frields. From the beginning e-mail was private. The Arpanet formed as a way for researchers to discuss their work over long-distances. The Arpanet, solely in existence as a government venture to assist in furthering of research, enjoyed a certain secrecy for a while. Once the Internt formed, the system allowed others inside as it no longer existed merely for the government. Much of the work on the Arpanet/Internet was necessarily private due to its nature. This made it even more important for e-mail to be private. Today the Internet includes not only what was the Arpanet (NSFNet), but companies and several BBS`s as well. Privacy is mor eimportant today than ever and should not even be an option on e-mail systems. It should be considered inherent in all systems.

  10. Assessment of the inherent allergenic potential of proteins in mice.

    PubMed Central

    Kimber, Ian; Stone, Sue; Dearman, Rebecca J

    2003-01-01

    There is considerable interest in the design of approaches that will permit the accurate identification and characterization of proteins that have the inherent potential to induce sensitization and cause food allergy. Among the methods used currently as part of such assessments are consideration of structural similarity to, or amino acid sequence homology with, known human allergens; whether there exists immunologic cross-reactivity with known allergens; and measurement of resistance to proteolytic digestion in a simulated gastric fluid. Although such approaches provide information that will contribute to a safety assessment, they do not--either individually or collectively--provide a direct evaluation of the ability of a novel protein to cause allergic sensitization. For this reason, work is in progress to design and evaluate suitable animal models that will provide a more holistic assessment of allergenic potential. In this laboratory, the approach we have taken has been to examine the characteristics of immune responses induced in mice following parenteral (intraperitoneal) exposure to test proteins. The basis of this method is to determine simultaneously the overall immunogenic potential of proteins [measured as a function of immunoglobulin (Ig) G antibody responses] and to compare this with their ability to provoke IgE antibody production, IgE being the antibody that effects allergic sensitization. Although this approach has not yet been evaluated fully, the results available to date suggest that it will be possible to distinguish proteins that have the inherent potential to induce allergic sensitization from those that do not. In this article we summarize progress to date in the context of the scientific background against which such methods are being developed. PMID:12573911

  11. Toxic release consequence analysis tool (TORCAT) for inherently safer design plant.

    PubMed

    Shariff, Azmi Mohd; Zaini, Dzulkarnain

    2010-10-15

    Many major accidents due to toxic release in the past have caused many fatalities such as the tragedy of MIC release in Bhopal, India (1984). One of the approaches is to use inherently safer design technique that utilizes inherent safety principle to eliminate or minimize accidents rather than to control the hazard. This technique is best implemented in preliminary design stage where the consequence of toxic release can be evaluated and necessary design improvements can be implemented to eliminate or minimize the accidents to as low as reasonably practicable (ALARP) without resorting to costly protective system. However, currently there is no commercial tool available that has such capability. This paper reports on the preliminary findings on the development of a prototype tool for consequence analysis and design improvement via inherent safety principle by utilizing an integrated process design simulator with toxic release consequence analysis model. The consequence analysis based on the worst-case scenarios during process flowsheeting stage were conducted as case studies. The preliminary finding shows that toxic release consequences analysis tool (TORCAT) has capability to eliminate or minimize the potential toxic release accidents by adopting the inherent safety principle early in preliminary design stage. PMID:20633985

  12. Inherent Anticipation in the Pharmaceutical and Biotechnology Industries.

    PubMed

    Goldman, Michael; Evans, Georgia; Zappia, Andrew

    2015-08-01

    Pharmaceutical and biotech research often involves discovering new properties of, or new methods to use, existing compositions. The doctrine of inherent anticipation, however, prevents the issuance and/or validity of a patent for discoveries deemed to have been implicitly disclosed in the prior art. This can be a barrier to patent rights in these technologies. Inherent anticipation therefore creates uncertainty for patent protection in the pharmaceutical and biotech sciences. Despite this uncertainty, Federal Circuit jurisprudence provides guidance on the boundaries of the inherent anticipation doctrine. In view of the case law, certain strategies may be employed to protect inventions that may potentially be viewed as inherent in the prior art. PMID:25877394

  13. Characterization of Irradiated Metal Waste from the Pyrometallurgical Treatment of Used EBR-II Fuel

    SciTech Connect

    B.R. Westphal; K.C. Marsden; W.M. McCartin; S.M. Frank; D.D. Keiser, Jr.; T.S. Yoo; D. Vaden; D.G. Cummings; K.J. Bateman; J. J. Giglio; T. P. O'Holleran; P. A. Hahn; M. N. Patterson

    2013-03-01

    As part of the pyrometallurgical treatment of used Experimental Breeder Reactor-II fuel, a metal waste stream is generated consisting primarily of cladding hulls laden with fission products noble to the electrorefining process. Consolidation by melting at high temperature [1873 K (1600 degrees C)] has been developed to sequester the noble metal fission products (Zr, Mo, Tc, Ru, Rh, Te, and Pd) which remain in the iron-based cladding hulls. Zirconium from the uranium fuel alloy (U-10Zr) is also deposited on the hulls and forms Fe-Zr intermetallics which incorporate the noble metals as well as residual actinides during processing. Hence, Zr has been chosen as the primary indicator for consistency of the metal waste. Recently, the first production-scale metal waste ingot was generated and sampled to monitor Zr content for Fe-Zr intermetallic phase formation and validation of processing conditions. Chemical assay of the metal waste ingot revealed a homogeneous distribution of the noble metal fission products as well as the primary fuel constituents U and Zr. Microstructural characterization of the ingot confirmed the immobilization of the noble metals in the Fe-Zr intermetallic phase.

  14. Characterization of Irradiated Metal Waste from the Pyrometallurgical Treatment of Used EBR-II Fuel

    NASA Astrophysics Data System (ADS)

    Westphal, Brian R.; Frank, S. M.; McCartin, W. M.; Cummings, D. G.; Giglio, J. J.; O'Holleran, T. P.; Hahn, P. A.; Yoo, T. S.; Marsden, K. C.; Bateman, K. J.; Patterson, M. N.

    2015-01-01

    As part of the pyrometallurgical treatment of used Experimental Breeder Reactor-II fuel, a metal waste stream is generated consisting primarily of cladding hulls laden with fission products noble to the electrorefining process. Consolidation by melting at high temperature [1873 K (1600 °C)] has been developed to sequester the noble metal fission products (Zr, Mo, Tc, Ru, Rh, Te, and Pd) which remain in the iron-based cladding hulls. Zirconium from the uranium fuel alloy (U-10Zr) is also deposited on the hulls and forms Fe-Zr intermetallics which incorporate the noble metals as well as residual actinides during processing. Hence, Zr has been chosen as the primary indicator for consistency of the metal waste. Recently, the first production-scale metal waste ingot was generated and sampled to monitor Zr content for Fe-Zr intermetallic phase formation and validation of processing conditions. Chemical assay of the metal waste ingot revealed a homogeneous distribution of the noble metal fission products as well as the primary fuel constituents U and Zr. Microstructural characterization of the ingot confirmed the immobilization of the noble metals in the Fe-Zr intermetallic phase.

  15. Implementation of inherence calculus in the PowerLoom environment

    NASA Astrophysics Data System (ADS)

    Wachulski, Marcin F.; Mulawka, Jan J.; Nieznański, Edward

    The article describes an attempt to implement abstract and concrete inherence calculi in the PowerLoom technology. Issues in the field of artificial intelligence, ontology and philosophy have been addressed. The inherence calculus is a type of a formal logic system. The PowerLoom technology consists of a knowledge representation language and an inference engine. Six inherence calculi have been implemented and an appropriate testing environment has been developed. The inherence calculus has been also extended by categorical properties and a theoretical discussion of ontological Boolean algebra has been conducted. Carried out experiments showed properties of the inherence calculi and also verified capabilities of PowerLoom to construct such logic systems. It occurred that expert system operational mode of PowerLoom outperforms its abilities to work as a mathematical theorem prover.

  16. The inherence heuristic as a source of essentialist thought.

    PubMed

    Salomon, Erika; Cimpian, Andrei

    2014-10-01

    Humans are essentialists: They believe hidden "essences" underlie membership in natural and social kinds. Although essentialism has well-established implications for important societal issues (e.g., discrimination), little is known about its origins. According to a recent proposal, essentialism emerges from a broader inherence heuristic-an intuitive tendency to explain patterns in terms of the inherent properties of their constituents (e.g., we have orange juice for breakfast [pattern] because citrus aromas [inherent feature] wake us up). We tested two predictions of this proposal-that reliance on the inherence heuristic predicts endorsement of essentialist beliefs, even when adjusting for potentially confounding variables (Studies 1 and 2), and that reducing reliance on the inherence heuristic produces a downstream reduction in essentialist thought (Studies 3 and 4). The results were consistent with these predictions and thus provided evidence for a new theoretical perspective on the cognitive underpinnings of psychological essentialism. PMID:25037751

  17. Sequential behavior and its inherent tolerance to memory faults.

    NASA Technical Reports Server (NTRS)

    Meyer, J. F.

    1972-01-01

    Representation of a memory fault of a sequential machine M by a function mu on the states of M and the result of the fault by an appropriately determined machine M(mu). Given some sequential behavior B, its inherent tolerance to memory faults can then be measured in terms of the minimum memory redundancy required to realize B with a state-assigned machine having fault tolerance type tau and fault tolerance level t. A behavior having maximum inherent tolerance is exhibited, and it is shown that behaviors of the same size can have different inherent tolerance.

  18. Thermally responsive polymer electrolytes for inherently safe electrochemical energy storage

    NASA Astrophysics Data System (ADS)

    Kelly, Jesse C.

    Electrochemical double layer capacitors (EDLCs), supercapacitors and Li-ion batteries have emerged as premier candidates to meet the rising demands in energy storage; however, such systems are limited by thermal hazards, thermal runaway, fires and explosions, all of which become increasingly more dangerous in large-format devices. To prevent such scenarios, thermally-responsive polymer electrolytes (RPEs) that alter properties in electrochemical energy storage devices were designed and tested. These RPEs will be used to limit or halt device operation when temperatures increase beyond a predetermined threshold, therefore limiting further heating. The development of these responsive systems will offer an inherent safety mechanism in electrochemical energy storage devices, while preserving the performance, lifetimes, and versatility that large-format systems require. Initial work focused on the development of a model system that demonstrated the concept of RPEs in an electrochemical device. Aqueous electrolyte solutions of polymers exhibiting properties that change in response to temperature were developed for applications in EDLCs and supercapacitors. These "smart materials" provide a means to control electrochemical systems where polymer phase separation at high temperatures affects electrolyte properties and inhibits device performance. Aqueous RPEs were synthesized using N-isopropylacrylamide, which governs the thermal properties, and fractions of acrylic acid or vinyl sulfonic acids, which provide ions to the solution. The molecular properties of these aqueous RPEs, specifically the ionic composition, were shown to influence the temperature-dependent electrolyte properties and the extent to which these electrolytes control the energy storage characteristics of a supercapacitor device. Materials with high ionic content provided the highest room temperature conductivity and electrochemical activity; however, RPEs with low ionic content provided the highest "on

  19. No inherent glassiness in a Penrose tiling quasicrystal

    SciTech Connect

    Strandburg, K.J.; Dressel, P.R.

    1988-11-01

    Consideration of the structure of the Penrose pattern has led to speculation that a system with a Penrose tiling ground state might be subject to inherent glassy behavior. Monte Carol simulations show, using a simple model of the energetics, that there is no inherent glassiness in the Penrose tiling. Thermodynamic quantities measured are completely reversible, displaying no observable hysterisis, and the system may be easily cooled from a highly disordered configuration into its lowest energy state. 11 refs., 7 figs.

  20. Evidence of inherent spontaneous polarization in the metazoan integument epithelia.

    PubMed Central

    Athenstaedt, H; Claussen, H

    1983-01-01

    The live integument epithelia of the metazoa have an inherent spontaneous polarization (an inherent permanent electric dipole moment) of corresponding direction perpendicular to the integument surface. The existence of the inherent polarization was proved by their temperature dependence, i.e., by the pyroelectric (PE) effect. Quantitative PE measurements were carried out on a number of integument epithelia of vertebrates (a) in vivo, (b) on fresh epidermis preparations, and (c) on dead, air-dried epidermis specimens of the same species. The demonstrated spontaneous polarization is not dependent on the living state and not caused by a potential difference between the outer and inner integument surface. Dead, dry epidermis samples (potential difference less than 0.01 mV) as well as dead, dry integument appendages (bristles, hairs), and dead cuticles (of arthropoda, annelida, nematoda) showed an inherent dipole moment of the same orientation as the live epidermis. The findings reveal a relationship between the direction (vector) of inherent spontaneous polarization and that of growth (morphogenesis) in the animal epidermis, their appendages, and cuticles. We conclude (a) that the inherent spontaneous polarization is present in live individual epithelial cells of the metazoan integument, and (b) that this physical property is related to the structural and functional cell polarity of integument epithelia and possibly of other epithelia. Images FIGURE 10 PMID:6838974

  1. Molybdenum disulfide (MoS2) nanoflakes as inherently electroactive labels for DNA hybridization detection.

    PubMed

    Loo, Adeline Huiling; Bonanni, Alessandra; Ambrosi, Adriano; Pumera, Martin

    2014-10-21

    The detection of specific DNA sequences plays a critical role in the areas of medical diagnostics, environmental monitoring, drug discovery and food safety. This has therefore become a strong driving force behind the ever-increasing demand for simple, cost-effective, highly sensitive and selective DNA biosensors. In this study, we report for the first time, a novel approach for the utilization of molybdenum disulfide nanoflakes, a member of the transition metal dichalcogenides family, in the detection of DNA hybridization. Herein, molybdenum disulfide nanoflakes serve as inherently electroactive labels, with the inherent oxidation peak exploited as the analytical signal. The principle of detection is based on the differential affinity of molybdenum disulfide nanoflakes towards single-stranded DNA and double-stranded DNA. The employment of transition metal dichalcogenide nanomaterials for sensing and biosensing purposes represents an upcoming research area which holds great promise. Hence, our findings are anticipated to have significant contributions towards the fabrication of future DNA biosensors. PMID:25177907

  2. Inherent limits on optimization and discovery in physical systems

    SciTech Connect

    Mlinar, Vladan

    2014-12-15

    Topological mapping of a large physical system on a graph, and its decomposition using universal measures are proposed. We find inherent limits to the potential for optimization of a given system and its approximate representations by motifs, and the ability to reconstruct the full system given approximate representations. The approximate representation of the system most suited for optimization may be different from that which most accurately describes the full system. - Highlights: • Graph-based approach to analyze full and partial representations of physical systems. • Direct link between a change in the physical system and complexity of the graph. • Inherent limits to the potential for optimization of a general system. • Inherent limits to the reconstruction of full system from partial representations.

  3. Assessing the inherent uncertainty of one-dimensional diffusions

    NASA Astrophysics Data System (ADS)

    Eliazar, Iddo; Cohen, Morrel H.

    2013-01-01

    In this paper we assess the inherent uncertainty of one-dimensional diffusion processes via a stochasticity classification which provides an à la Mandelbrot categorization into five states of uncertainty: infra-mild, mild, borderline, wild, and ultra-wild. Two settings are considered. (i) Stopped diffusions: the diffusion initiates from a high level and is stopped once it first reaches a low level; in this setting we analyze the inherent uncertainty of the diffusion's maximal exceedance above its initial high level. (ii) Stationary diffusions: the diffusion is in dynamical statistical equilibrium; in this setting we analyze the inherent uncertainty of the diffusion's equilibrium level. In both settings general closed-form analytic results are established, and their application is exemplified by stock prices in the stopped-diffusions setting, and by interest rates in the stationary-diffusions setting. These results provide a highly implementable decision-making tool for the classification of uncertainty in the context of one-dimensional diffusions.

  4. A battery-run pulsed motor with inherent dynamic electronic switch control

    NASA Astrophysics Data System (ADS)

    Tripathi, K. C.; Lal, P.; Sarma, P. R.; Sharma, A. K.; Prakash, V.

    1980-02-01

    A new type of battery-run brushless ferrite-magnet dc motor system is described. Its rotor part consists of a few permanent ceramic (ferrite) magnets uniformly spread on the rim of a disk (wheel) and the stator part consists of electromagnets placed in such a way that when energized, they always form a repulsive couple to rotate the disk. A sensor coil is placed to give an induced pulse signal, which acts as an inherent dynamic switching time control for the automatic electronic control system. Control of speed, brake system, and safety measures are also discussed. Experimental values for the present system are given. Some possible applications are suggested.

  5. Integration of inherent and induced chirality into subphthalocyanine analogue

    NASA Astrophysics Data System (ADS)

    Zhao, Luyang; Qi, Dongdong; Wang, Kang; Wang, Tianyu; Han, Bing; Tang, Zhiyong; Jiang, Jianzhuang

    2016-06-01

    Conventional conjugated systems are characteristic of only either inherent or induced chirality because of synthetic challenge in combination of chiral segment into the main chromophore. In this work, chiral binaphthyl segment is directly fused into the central chromophore of a subphthalocyanine skeleton, resulting in a novel type of chiral subphthalocyanine analogue (R/S)-1 of integrated inherent and induced chirality. Impressively, an obviously enhanced optical activity is discerned for (R/S)-1 molecules, and corresponding enhancement mechanism is elucidated in detail. The synthesis strategy based on rational molecular design will open the door towards fabrication of chiral materials with giant optical activity, which will have great potential in chiroptical devices.

  6. Model development for the dynamic analysis of the OSU inherently safe reactor. Part 1

    SciTech Connect

    Aybar, H.S.

    1992-12-31

    Faculty and students in the Nuclear Engineering Program at the Ohio State University (OSU) have proposed a conceptual design for an inherently safe 340 MWe power reactor. The design is based on the state-of-the-art technology of LWRs and the High Temperature Gas- cooled Reactors (HTGRs). The OSU Inherently Safe Reactor (OSU-ISR) concept uses shorter than standard BWR fuel elements in the reactor core. All the fluid on the primary side is contained within a Prestressed Concrete Reactor Vessel (PCRV). This important feature significantly reduces the probability of a LOCA. A new feature of the OSU-ISR is an operator independent steam driven Emergency Core Cooling System (ECCS) housed within the PCRV. In accident conditions where the steam generators are incapacitated, steam from the core drives a jet injector, which takes water from the suppression pool and pumps it into the core cavity to maintain core coverability. The preliminary analysis of the concept was performed as a design project in the Nuclear Engineering Program at the OSU during the Spring of 1985, and published in ``Nuclear Technology.`` The use of a PCRV for ducting and containment and the replacement of forced recirculation with natural circulation on the primary side significantly improve the inherent safety of the plant. Currently, work is in progress for the refinement of the OSU-ISR concept, partially supported by a grant from the U.S. Department of Energy.

  7. Research Challenges Inherent in Determining Improvement in University Teaching

    ERIC Educational Resources Information Center

    Devlin, Marcia

    2008-01-01

    Using a recent study that examined the effectiveness of a particular approach to improving individual university teaching as a case study, this paper examines some of the challenges inherent in educational research, particularly research examining the effects of interventions to improve teaching. Aspects of the research design and methodology and…

  8. Contracting for Independent Evaluation: Approaches to an Inherent Tension

    ERIC Educational Resources Information Center

    Klerman, Jacob Alex

    2010-01-01

    There has recently been discussion of whether independent contract evaluation is possible. This article acknowledges the inherent tension in contract evaluation and in response suggests a range of constructive approaches to improving the independence of contract evaluation. In particular, a clear separation between the official evaluation report…

  9. Safety and IVHM

    NASA Technical Reports Server (NTRS)

    Goebel, Kai

    2012-01-01

    When we address safety in a book on the business case for IVHM, the question arises whether safety isn t inherently in conflict with the need of operators to run their systems as efficiently (and as cost effectively) as possible. The answer may be that the system needs to be just as safe as needed, but not significantly more. That begs the next question: How safe is safe enough? Several regulatory bodies provide guidelines for operational safety, but irrespective of that, operators do not want their systems to be known as lacking safety. We illuminate the role of safety within the context of IVHM.

  10. Preservation of FFTF Data Related to Passive Safety Testing

    SciTech Connect

    Wootan, David W.; Butner, R. Scott; Omberg, Ronald P.; Makenas, Bruce J.; Nielsen, Deborah L.

    2010-10-01

    One of the goals of the Fuel Cycle Research and Development Program (FCRD) is to preserve the knowledge that has been gained in the United States on Liquid Metal Reactors (LMR). A key area deserving special attention for preservation is the data relating to passive safety testing that was conducted in FFTF and EBR-II during the 1980’s. Accidents at Unit 4 of the Chernobyl Station and Unit 2 at Three Mile Island changed the safety paradigm of the nuclear power industry. New emphasis was placed on assured safety based on intrinsic plant characteristics that protect not only the public, but the significant investment in the plant as well. Plants designated to perform in this manner are considered to be passively safe since no active sensor/alarm system or human intervention is required to bring the reactor to a safe shutdown condition. The liquid metal reactor (LMR) has several key characteristics needed for a passively safe reactor: reactor coolant with superior heat transfer capability and very high boiling point, low (atmospheric) system pressures, and reliable negative reactivity feedback. The credibility of the design for a passively safe LMR rests on two issues: the validity of analytic methods used to predict passive safety performance and the availability of relevant test data to calibrate design tools. Safety analysis methods used to analyze LMRs under the old safety paradigm were focused on calculating the source term for the Core Disruptive Accident. Passive safety design requires refined analysis methods for transient events because treatment of the detailed reactivity feedbacks is important in predicting the response of the reactor. Similarly, analytic tools should be calibrated against actual test experience in existing LMR facilities. The principal objectives of the combined FFTF natural circulation and Passive Safety Testing program were: 1) to verify natural circulation as a reliable means to safely remove decay heat, 2) to extend passive safety

  11. Advances in coupled safety modeling using systems analysis and high-fidelity methods.

    SciTech Connect

    Fanning, T. H.; Thomas, J. W.; Nuclear Engineering Division

    2010-05-31

    The potential for a sodium-cooled fast reactor to survive severe accident initiators with no damage has been demonstrated through whole-plant testing in EBR-II and FFTF. Analysis of the observed natural protective mechanisms suggests that they would be characteristic of a broad range of sodium-cooled fast reactors utilizing metal fuel. However, in order to demonstrate the degree to which new, advanced sodium-cooled fast reactor designs will possess these desired safety features, accurate, high-fidelity, whole-plant dynamics safety simulations will be required. One of the objectives of the advanced safety-modeling component of the Reactor IPSC is to develop a science-based advanced safety simulation capability by utilizing existing safety simulation tools coupled with emerging high-fidelity modeling capabilities in a multi-resolution approach. As part of this integration, an existing whole-plant systems analysis code has been coupled with a high-fidelity computational fluid dynamics code to assess the impact of high-fidelity simulations on safety-related performance. With the coupled capabilities, it is possible to identify critical safety-related phenomenon in advanced reactor designs that cannot be resolved with existing tools. In this report, the impact of coupling is demonstrated by evaluating the conditions of outlet plenum thermal stratification during a protected loss of flow transient. Outlet plenum stratification was anticipated to alter core temperatures and flows predicted during natural circulation conditions. This effect was observed during the simulations. What was not anticipated, however, is the far-reaching impact that resolving thermal stratification has on the whole plant. The high temperatures predicted at the IHX inlet due to thermal stratification in the outlet plenum forces heat into the intermediate system to the point that it eventually becomes a source of heat for the primary system. The results also suggest that flow stagnation in the

  12. Speeding up local correlation methods: System-inherent domains

    NASA Astrophysics Data System (ADS)

    Kats, Daniel

    2016-07-01

    A new approach to determine local virtual space in correlated calculations is presented. It restricts the virtual space in a pair-specific manner on the basis of a preceding approximate calculation adapting automatically to the locality of the studied problem. The resulting pair system-inherent domains are considerably smaller than the starting domains, without significant loss in the accuracy. Utilization of such domains speeds up integral transformations and evaluations of the residual and reduces memory requirements. The system-inherent domains are especially suitable in cases which require high accuracy, e.g., in generation of pair-natural orbitals, or for which standard domains are problematic, e.g., excited-state calculations.

  13. The inherent mutational tolerance and antigenic evolvability of influenza hemagglutinin.

    PubMed

    Thyagarajan, Bargavi; Bloom, Jesse D

    2014-01-01

    Influenza is notable for its evolutionary capacity to escape immunity targeting the viral hemagglutinin. We used deep mutational scanning to examine the extent to which a high inherent mutational tolerance contributes to this antigenic evolvability. We created mutant viruses that incorporate most of the ≈10(4) amino-acid mutations to hemagglutinin from A/WSN/1933 (H1N1) influenza. After passaging these viruses in tissue culture to select for functional variants, we used deep sequencing to quantify mutation frequencies before and after selection. These data enable us to infer the preference for each amino acid at each site in hemagglutinin. These inferences are consistent with existing knowledge about the protein's structure and function, and can be used to create a model that describes hemagglutinin's evolution far better than existing phylogenetic models. We show that hemagglutinin has a high inherent tolerance for mutations at antigenic sites, suggesting that this is one factor contributing to influenza's antigenic evolution. PMID:25006036

  14. Speeding up local correlation methods: System-inherent domains.

    PubMed

    Kats, Daniel

    2016-07-01

    A new approach to determine local virtual space in correlated calculations is presented. It restricts the virtual space in a pair-specific manner on the basis of a preceding approximate calculation adapting automatically to the locality of the studied problem. The resulting pair system-inherent domains are considerably smaller than the starting domains, without significant loss in the accuracy. Utilization of such domains speeds up integral transformations and evaluations of the residual and reduces memory requirements. The system-inherent domains are especially suitable in cases which require high accuracy, e.g., in generation of pair-natural orbitals, or for which standard domains are problematic, e.g., excited-state calculations. PMID:27394095

  15. Integration of inherent and induced chirality into subphthalocyanine analogue

    PubMed Central

    Zhao, Luyang; Qi, Dongdong; Wang, Kang; Wang, Tianyu; Han, Bing; Tang, Zhiyong; Jiang, Jianzhuang

    2016-01-01

    Conventional conjugated systems are characteristic of only either inherent or induced chirality because of synthetic challenge in combination of chiral segment into the main chromophore. In this work, chiral binaphthyl segment is directly fused into the central chromophore of a subphthalocyanine skeleton, resulting in a novel type of chiral subphthalocyanine analogue (R/S)-1 of integrated inherent and induced chirality. Impressively, an obviously enhanced optical activity is discerned for (R/S)-1 molecules, and corresponding enhancement mechanism is elucidated in detail. The synthesis strategy based on rational molecular design will open the door towards fabrication of chiral materials with giant optical activity, which will have great potential in chiroptical devices. PMID:27294871

  16. Determination of Inherent Stresses by Measuring Deformations of Drilled Holes

    NASA Technical Reports Server (NTRS)

    Mathar, Josef

    1933-01-01

    Various methods have been proposed for determining the inherent stresses in structural components by disturbing their stress equilibrium through a mechanical device and measuring the resulting deformations. The methods used have disadvantages because they can be used only with specially shaped pieces (those with round or rectangular cross sections), that every form of test piece requires another kind of injury and hence of calculation, and the tested parts are rendered useless. The new test method, which seeks to eliminate these disadvantages, is likewise based on a disturbance of the equilibrium of forces, and indeed by drilling a hole which, however, is so small that the part can be used again. This method serves, among other things, for determining the inherent stresses in castings, welded parts, rolled structural shapes and finished structures.

  17. Integration of inherent and induced chirality into subphthalocyanine analogue.

    PubMed

    Zhao, Luyang; Qi, Dongdong; Wang, Kang; Wang, Tianyu; Han, Bing; Tang, Zhiyong; Jiang, Jianzhuang

    2016-01-01

    Conventional conjugated systems are characteristic of only either inherent or induced chirality because of synthetic challenge in combination of chiral segment into the main chromophore. In this work, chiral binaphthyl segment is directly fused into the central chromophore of a subphthalocyanine skeleton, resulting in a novel type of chiral subphthalocyanine analogue (R/S)-1 of integrated inherent and induced chirality. Impressively, an obviously enhanced optical activity is discerned for (R/S)-1 molecules, and corresponding enhancement mechanism is elucidated in detail. The synthesis strategy based on rational molecular design will open the door towards fabrication of chiral materials with giant optical activity, which will have great potential in chiroptical devices. PMID:27294871

  18. Molybdenum disulfide (MoS2) nanoflakes as inherently electroactive labels for DNA hybridization detection

    NASA Astrophysics Data System (ADS)

    Loo, Adeline Huiling; Bonanni, Alessandra; Ambrosi, Adriano; Pumera, Martin

    2014-09-01

    The detection of specific DNA sequences plays a critical role in the areas of medical diagnostics, environmental monitoring, drug discovery and food safety. This has therefore become a strong driving force behind the ever-increasing demand for simple, cost-effective, highly sensitive and selective DNA biosensors. In this study, we report for the first time, a novel approach for the utilization of molybdenum disulfide nanoflakes, a member of the transition metal dichalcogenides family, in the detection of DNA hybridization. Herein, molybdenum disulfide nanoflakes serve as inherently electroactive labels, with the inherent oxidation peak exploited as the analytical signal. The principle of detection is based on the differential affinity of molybdenum disulfide nanoflakes towards single-stranded DNA and double-stranded DNA. The employment of transition metal dichalcogenide nanomaterials for sensing and biosensing purposes represents an upcoming research area which holds great promise. Hence, our findings are anticipated to have significant contributions towards the fabrication of future DNA biosensors.The detection of specific DNA sequences plays a critical role in the areas of medical diagnostics, environmental monitoring, drug discovery and food safety. This has therefore become a strong driving force behind the ever-increasing demand for simple, cost-effective, highly sensitive and selective DNA biosensors. In this study, we report for the first time, a novel approach for the utilization of molybdenum disulfide nanoflakes, a member of the transition metal dichalcogenides family, in the detection of DNA hybridization. Herein, molybdenum disulfide nanoflakes serve as inherently electroactive labels, with the inherent oxidation peak exploited as the analytical signal. The principle of detection is based on the differential affinity of molybdenum disulfide nanoflakes towards single-stranded DNA and double-stranded DNA. The employment of transition metal dichalcogenide

  19. Inherent security benefits of underground dry storage of nuclear materials

    SciTech Connect

    Moore, R.D.; Zahn, T.

    1997-07-01

    This paper, augmented by color slides and handouts, will examine the inherent security benefits of underground dry storage of nuclear materials. Specific items to be presented include: the successful implementation of this type of storage configuration at Argonne National Laboratory - West; facility design concepts with security as a primary consideration; physical barriers achieved by container design; detection, assessment, and monitoring capabilities; and {open_quotes}self protection{close_quotes} strategies. This is a report on the security features of such a facility. The technical operational aspects of the facility are beyond the scope of this paper.

  20. Construction of IMEX methods with inherent Runge-Kutta stability

    NASA Astrophysics Data System (ADS)

    Braś, Michał; Izzo, Giuseppe; Jackiewicz, Zdzislaw

    2016-06-01

    We describe construction of implicit-explicit (IMEX) general linear methods (GLMs) with inherent Runge-Kutta stability (IRKS) for differential systems with non-stiff and stiff processes. We will use the extrapolation approach to remove implicitness in the non-stiff terms to compute unknown stage values in terms of stage derivatives at the previous step and those already computed in the current step. Highly stable IMEX GLMs of stage order equal to the order were derived up to the order four. These methods do not suffer from order reduction phenomenon which is confirmed by numerical experiments.

  1. Inherent uncertainties in meteorological parameters for wind turbine design

    NASA Technical Reports Server (NTRS)

    Doran, J. C.

    1982-01-01

    Major difficulties associated with meteorological measurments such as the inability to duplicate the experimental conditions from one day to the next are discussed. This lack of consistency is compounded by the stochastic nature of many of the meteorological variables of interest. Moreover, simple relationships derived in one location may be significantly altered by topographical or synoptic differences encountered at another. The effect of such factors is a degree of inherent uncertainty if an attempt is made to describe the atmosphere in terms of universal laws. Some of these uncertainties and their causes are examined, examples are presented and some implications for wind turbine design are suggested.

  2. Application of inherent fluorescence in the diagnosis of early cancer

    NASA Astrophysics Data System (ADS)

    Yu, Zhen-Fen

    1998-11-01

    There are differences in molecular structure between cancer, ulcer and normal tissue. They have their own specific absorb structures, which result in the highly specificity in the absorption of radiation. When laser light with specific wavelength irradiates on cancer or normal tissue, the inherent fluorescence of them can be stimulated. With the help of specific instrument, the curve of spectrum can be drawn. The various fluorescence peak value of cancerous and normal tissue can be used to differentiate between the two. The instruments used include some kinds of the most advanced technologies in nowadays, such as current laser, photoelectron, computer, microptic rapid spectrum analysis.

  3. Physics review on inherently safe features of ESBWR

    SciTech Connect

    Chiang, R. T.; Fawcett, R. M.; Cheung, Y. K.; Chung, A. K.

    2006-07-01

    The scope of this physics review includes: 1) the major differences among ESBWR, ABWR and conventional BWR cores, 2) the reason why ESBWR operation is inherently safe based on stability analysis, 3) an innovative wide-blades control rod conceptual core design to reduce cost by reducing number of control rod drives by near 50% for a natural circulation BWR, and 4) an innovative top-entry control rod conceptual core design to take advantage of additional space in the chimney area in order to reduce the plant size and cost for a natural circulation BWR. (authors)

  4. Inherent uncertainties in meteorological parameters for wind-turbine design

    SciTech Connect

    Doran, J.C.

    1981-08-01

    One of the major difficulties associated with meteorological measurements is the inability to duplicate the experimental conditions from one day to the next. This lack of consistency is compounded by the stochastic nature of many of the meteorological variables of interest. Moreover, simple relationships derived in one location may be significantly altered by topographical or synoptic differences encountered at another. The effect of such factors is a degree of inherent uncertainty if an attempt is made to describe the atmosphere in terms of universal laws. In this paper some of these uncertainties and their causes are examined, examples are presented and some implications for wind turbine design are suggested.

  5. Aerospace Safety Advisory Panel

    NASA Technical Reports Server (NTRS)

    1992-01-01

    The results of the Panel's activities are presented in a set of findings and recommendations. Highlighted here are both improvements in NASA's safety and reliability activities and specific areas where additional gains might be realized. One area of particular concern involves the curtailment or elimination of Space Shuttle safety and reliability enhancements. Several findings and recommendations address this area of concern, reflecting the opinion that safety and reliability enhancements are essential to the continued successful operation of the Space Shuttle. It is recommended that a comprehensive and continuing program of safety and reliability improvements in all areas of Space Shuttle hardware/software be considered an inherent component of ongoing Space Shuttle operations.

  6. Process inherent ultimate safety/boiling-water reactor PIUS/BWR

    SciTech Connect

    Forsberg, C.W.

    1985-01-01

    This document is a series of viewgraphs on: design basis of PIUS/BWR, definition of PIUS/BWR, mechanisms of safe shutdown and afterheat cooling, advantages of PIUS/BWR, and research and development requirements. (DLC)

  7. REDUCTION OF INHERENT MERCURY EMISSIONS IN PC COMBUSTION

    SciTech Connect

    John C. Kramlich; Rebecca N. Sliger; David J. Going

    1999-08-06

    Mercury emission compliance presents one of the major potential challenges raised by the 1990 Clean Air Act Amendments. Simple ways of controlling emissions have not been identified. The variability in the field data suggest that inherent mercury emissions may be reduced if the source of this inherent capture can be identified and controlled. The key mechanisms appear to involve the oxidation of mercury to Hg{sup 2}, generally producing the more reactive HgCl{sub 2}, followed by its capture by certain components of the fly ash or char, or in the air pollution control equipment. This research focuses on identifying the rate-limiting steps associated with the oxidation step. Work in this reporting period focused on the refinement of the rate constants used in the kinetic mechanism for mercury oxidation. The possible reactions leading to mercury oxidation are reviewed. Rate constants for these reactions are discussed, using both literature sources and detailed estimates. The resulting mechanism represents the best present picture of the overall chlorine homogeneous oxidation chemistry. Application of this mechanism to the data will be explored in the subsequent reporting period. Work conducted under the present grant has been the subject of two meeting papers presented during the reporting period (Sliger et al., 1998a,b).

  8. Landslide Hazard Probability Derived from Inherent and Dynamic Determinants

    NASA Astrophysics Data System (ADS)

    Strauch, Ronda; Istanbulluoglu, Erkan

    2016-04-01

    Landslide hazard research has typically been conducted independently from hydroclimate research. We unify these two lines of research to provide regional scale landslide hazard information for risk assessments and resource management decision-making. Our approach combines an empirical inherent landslide probability with a numerical dynamic probability, generated by combining routed recharge from the Variable Infiltration Capacity (VIC) macro-scale land surface hydrologic model with a finer resolution probabilistic slope stability model run in a Monte Carlo simulation. Landslide hazard mapping is advanced by adjusting the dynamic model of stability with an empirically-based scalar representing the inherent stability of the landscape, creating a probabilistic quantitative measure of geohazard prediction at a 30-m resolution. Climatology, soil, and topography control the dynamic nature of hillslope stability and the empirical information further improves the discriminating ability of the integrated model. This work will aid resource management decision-making in current and future landscape and climatic conditions. The approach is applied as a case study in North Cascade National Park Complex, a rugged terrain with nearly 2,700 m (9,000 ft) of vertical relief, covering 2757 sq km (1064 sq mi) in northern Washington State, U.S.A.

  9. Determination of inherent optical properties of Lake Ontario coastal waters.

    PubMed

    Bukata, R P; Jerome, J H; Bruton, J E; Jain, S C

    1979-12-01

    Two optical models (one based upon Monte Carlo simulations of the solutions of the radiative transfer equations and one based upon exponential/quasi-single scattering simulations) relating the apparent and inherent optical properties of natural water masses are utilized in conjunction with directly measured values of the irradiance attenuation coefficient K(0), the diffuse reflectance R(0), and the total attenuation coefficient c to determine the inherent optical properties of Lake Ontario coastal waters. Tables are presented displaying the calculated values of scattering albedo omega(0), forwardscattering probability F, backscattering probability B, absorption coefficient a, and scattering coefficient b as a function of wavelength. From the tables of calculated values, it is shown that both F and b display a spectral invariance, while omega(0) displays distinct spectral variations, the spectral variations apparent in the measured values of c may be attributable to spectral variations in a, and B displays a spectral change that varies inversely with the spectral change in a and c. The volume scattering phase function beta(theta) appears to be altered by the absorption characteristics of the water mass, contrary to the generally accepted premise that absorption and particulate backscattering are independent processes. PMID:20216727

  10. REDUCTION OF INHERENT MERCURY EMISSIONS IN PC COMBUSTION

    SciTech Connect

    John C. Kramlich; Rebecca N. Sliger; David J. Going

    1999-08-06

    Mercury emission compliance is one of the major potential challenges raised by the 1990 Clean Air Act Amendments. Simple ways of controlling emissions have not been identified. The variability in the field data suggests that inherent mercury emissions may be reduced if the source of this inherent capture can be identified and controlled. The key mechanisms appear to involve the oxidation of the mercury to Hg{sup 2}, generally producing the more reactive HgCl{sub 2} , followed by its capture by certain components of the fly ash or char. This research focuses on identifying the rate-limiting steps associated with the oxidation step. Work in this reporting period focused on the development and application of a kinetics model to the oxidation data developed in the present program and literature data under MSW conditions. The results indicate that the pathway Hg + Cl = HgCl followed by HgCl + HCl = HgCl{sub 2} + H predominates over Hg + Cl{sub 2} under high-temperature conditions. This primarily occurs because Cl{sub 2} concentrations are too low under the present conditions to contribute significantly.

  11. Estimation of inherent optical properties from CZMIL lidar

    NASA Astrophysics Data System (ADS)

    Kim, Minsu; Feygels, Viktor; Kopilevich, Yuri; Park, Joong Yong

    2014-11-01

    Bathymetric lidar has been widely used for ocean floor mapping. By identifying two distinctive return peaks, one from the water surface and the other from the bottom, the water depth can be estimated. In addition to bathymetry, it is also possible to estimate the optical properties of the water by analyzing the lidar return waveform. Only the few systems (e.g. Optech's SHOALS and CZMIL systems) that have good radiometric calibration demonstrate the capability to product the water's inherent optical properties and bottom reflectance. As the laser pulse propagates through the water, it is scattered by the water constituents. The directional distribution of scattered radiant power is determined by the volume scattering function. Only the backscattering within a very narrow solid angle around the 180° scattering angle travels back to the detector. During the two-way travel it experiences the same optical interaction (absorption and scattering) with the water constituents. Thus, the lidar return waveform between the surface and bottom peak contains information about the vertical distribution of the water attenuation coefficient and the backscattering coefficient in the form of the rate of change of the return power. One challenge is how to estimate the inherent attenuation from the apparent attenuation. In this research we propose a technique to estimate the true water attenuation coefficient from the total system attenuation. We use a lidar waveform simulator that solves the irradiance distribution on the beam cross-section using an analytical Fourier transform of the radiance based on a single-scattering approximation.

  12. Inherent Prevention and Mitigation of Severe Accident Consequences in Sodium-Cooled Fast Reactors

    SciTech Connect

    Roald A. Wigeland; James E. Cahalan

    2011-04-01

    Safety challenges for sodium-cooled fast reactors include maintaining core temperatures within design limits and assuring the geometry and integrity of the reactor core. Due to the high power density in the reactor core, heat removal requirements encourage the use of high-heat-transfer coolants such as liquid sodium. The variation of power across the core requires ducted assemblies to control fuel and coolant temperatures, which are also used to constrain core geometry. In a fast reactor, the fuel is not in the most neutronically reactive configuration during normal operation. Accidents leading to fuel melting, fuel pin failure, and fuel relocation can result in positive reactivity, increasing power, and possibly resulting in severe accident consequences including recriticalities that could threaten reactor and containment integrity. Inherent safety concepts, including favorable reactivity feedback, natural circulation cooling, and design choices resulting in favorable dispersive characteristics for failed fuel, can be used to increase the level of safety to the point where it is highly unlikely, or perhaps even not credible, for such severe accident consequences to occur.

  13. Controllability of inherently damped large flexible space structures

    NASA Technical Reports Server (NTRS)

    Reddy, A. S. S. R.; Bainum, P. M.

    1982-01-01

    Graph theoretic techniques are used to study controllability of linear systems which represent large flexible orbiting space systems with inherent damping. The controllability of the pair of matrices representing the system state and control influence matrices is assured when all states in the model are reachable in a digraph sense from at least one input and also when the term rank of a Boolean matrix whose non trivial components are based on the state and control influence matrices has a term rank of the order of the state vector. The damping matrix does not influence the required number of actuators but gives flexibility to the possibility locations of the actuators for which the system is controllable.

  14. The centrosome cycle: Centriole biogenesis, duplication and inherent asymmetries

    PubMed Central

    Nigg, Erich A.; Stearns, Tim

    2013-01-01

    Centrosomes are microtubule-organizing centres of animal cells. They influence the morphology of the microtubule cytoskeleton, function as the base for the primary cilium and serve as a nexus for important signalling pathways. At the core of a typical centrosome are two cylindrical microtubule-based structures termed centrioles, which recruit a matrix of associated pericentriolar material. Cells begin the cell cycle with exactly one centrosome, and the duplication of centrioles is constrained such that it occurs only once per cell cycle and at a specific site in the cell. As a result of this duplication mechanism, the two centrioles differ in age and maturity, and thus have different functions; for example, the older of the two centrioles can initiate the formation of a ciliary axoneme. We discuss spatial aspects of the centrosome duplication cycle, the mechanism of centriole assembly and the possible consequences of the inherent asymmetry of centrioles and centrosomes. PMID:21968988

  15. Inherent costs and interdependent impacts of infrastructure network resilience.

    PubMed

    Baroud, Hiba; Barker, Kash; Ramirez-Marquez, Jose E; Rocco, Claudio M

    2015-04-01

    Recent studies in system resilience have proposed metrics to understand the ability of systems to recover from a disruptive event, often offering a qualitative treatment of resilience. This work provides a quantitative treatment of resilience and focuses specifically on measuring resilience in infrastructure networks. Inherent cost metrics are introduced: loss of service cost and total network restoration cost. Further, "costs" of network resilience are often shared across multiple infrastructures and industries that rely upon those networks, particularly when such networks become inoperable in the face of disruptive events. As such, this work integrates the quantitative resilience approach with a model describing the regional, multi-industry impacts of a disruptive event to measure the interdependent impacts of network resilience. The approaches discussed in this article are deployed in a case study of an inland waterway transportation network, the Mississippi River Navigation System. PMID:24924523

  16. Inherent variability in lead and copper collected during standardized sampling.

    PubMed

    Masters, Sheldon; Parks, Jeffrey; Atassi, Amrou; Edwards, Marc A

    2016-03-01

    Variability in the concentration of lead and copper sampled at consumers' taps poses challenges to assessing consumer health threats and the effectiveness of corrosion control. To examine the minimum variability that is practically achievable, standardized rigs with three lead and copper containing plumbing materials (leaded brass, copper tube with lead solder, and a lead copper connection) were deployed at five utilities and sampled with regimented protocols. Variability represented by relative standard deviation (RSD) in lead release was high in all cases. The brass had the lowest variability in lead release (RSD = 31 %) followed by copper-solder (RSD = 49%) and lead-copper (RSD = 80%). This high inherent variability is due to semi-random detachment of particulate lead to water, and represents a modern reality of water lead problems that should be explicitly acknowledged and considered in all aspects of exposure, public education, and monitoring. PMID:26896965

  17. A novel hyperbolic grid generation procedure with inherent adaptive dissipation

    SciTech Connect

    Tai, C.H.; Yin, S.L.; Soong, C.Y.

    1995-01-01

    This paper reports a novel hyperbolic grid-generation with an inherent adaptive dissipation (HGAD), which is capable of improving the oscillation and overlapping of grid lines. In the present work upwinding differencing is applied to discretize the hyperbolic system and, thereby, to develop the adaptive dissipation coefficient. Complex configurations with the features of geometric discontinuity, exceptional concavity and convexity are used as the test cases for comparison of the present HGAD procedure with the conventional hyerbolic and elliptic ones. The results reveal that the HGAD method is superior in orthogonality and smoothness of the grid system. In addition, the computational efficiency of the flow solver may be improved by using the present HGAD procedure. 15 refs., 8 figs.

  18. Contracting for independent evaluation: approaches to an inherent tension.

    PubMed

    Klerman, Jacob Alex

    2010-08-01

    There has recently been discussion of whether independent contract evaluation is possible. This article acknowledges the inherent tension in contract evaluation and in response suggests a range of constructive approaches to improving the independence of contract evaluation. In particular, a clear separation between the official evaluation report and a contractor's own publication of analysis from the underlying evaluation appears to be a promising approach. In this approach, the funder would retain almost unfettered rights to the official contract report (including the right never to publish but not the right to change the contractor's text while leaving the contractor's authorship) and the contractor would retain clearly defined rights to publish any findings from the evaluation (subject only to the limitations of human subjects and proprietary data and some minimal notice). PMID:20519693

  19. Characterization of inherent curvature in DNA lacking polyadenine runs.

    PubMed

    McNamara, P T; Harrington, R E

    1991-07-01

    Sequence-directed DNA curvature is most commonly associated with AA dinucleotides in the form of polyadenine runs. We demonstrate inherent curvature in DNA which lacks AA/TT dinucleotides using the criteria of polyacrylamide gel mobility and efficiency of DNA cyclization. These studies are based upon two 21-base pair synthetic DNA fragments designed to exhibit fixed curvature according to deflections made to the helical axis by non-AA dinucleotide stacks. Repeats of these sequences display anomalously slow migration in polyacrylamide gels. Moreover, both sequences describe helical conformations that are closed into circles by DNA ligase at much smaller sizes than is typical of nondeformed DNA. Chemical cleavage of these DNA molecules with hydroxyl radical is also consistent with local variation in helical conformation at specific dinucleotide steps. PMID:1648100

  20. Deep seawater inherent optical properties in the Southern Ionian Sea

    NASA Astrophysics Data System (ADS)

    Riccobene, G.; Capone, A.; Aiello, S.; Ambriola, M.; Ameli, F.; Amore, I.; Anghinolfi, M.; Anzalone, A.; Avanzini, C.; Barbarino, G.; Barbarito, E.; Battaglieri, M.; Bellotti, R.; Beverini, N.; Bonori, M.; Bouhadef, B.; Brescia, M.; Cacopardo, G.; Cafagna, F.; Caponetto, L.; Castorina, E.; Ceres, A.; Chiarusi, T.; Circella, M.; Cocimano, R.; Coniglione, R.; Cordelli, M.; Costa, M.; Cuneo, S.; D'Amico, A.; de Bonis, G.; de Marzo, C.; de Rosa, G.; de Vita, R.; Distefano, C.; Falchini, E.; Fiorello, C.; Flaminio, V.; Fratini, K.; Gabrielli, A.; Galeotti, S.; Gandolfi, E.; Grimaldi, A.; Habel, R.; Leonora, E.; Lonardo, A.; Longo, G.; Lo Presti, D.; Lucarelli, F.; Maccioni, E.; Margiotta, A.; Martini, A.; Masullo, R.; Megna, R.; Migneco, E.; Mongelli, M.; Montaruli, T.; Morganti, M.; Musumeci, M.; Nicolau, C. A.; Orlando, A.; Osipenko, M.; Osteria, G.; Papaleo, R.; Pappalardo, V.; Petta, C.; Piattelli, P.; Raffaelli, F.; Raia, G.; Randazzo, N.; Reito, S.; Ricco, G.; Ripani, M.; Rovelli, A.; Ruppi, M.; Russo, G. V.; Russo, S.; Russo, S.; Sapienza, P.; Sedita, M.; Schuller, J.-P.; Shirokov, E.; Simeone, F.; Sipala, V.; Spurio, M.; Taiuti, M.; Terreni, G.; Trasatti, L.; Urso, S.; Valente, V.; Vicini, P.

    2007-02-01

    The NEMO (NEutrino Mediterranean Observatory) Collaboration has been carrying out since 1998 an evaluation programme of deep sea sites suitable for the construction of the future Mediterranean km3 Čerenkov neutrino telescope. We investigated the seawater optical and oceanographic properties of several deep sea marine areas close to the Italian Coast. Inherent optical properties (light absorption and attenuation coefficients) have been measured as a function of depth using an experimental apparatus equipped with standard oceanographic probes and the commercial transmissometer AC9 manufactured by WETLabs. This paper reports on the visible light absorption and attenuation coefficients measured in deep seawater of a marine region located in the Southern Ionian Sea, 60 100 km SE of Capo Passero (Sicily). Data show that blue light absorption coefficient is about 0.015 m-1 (corresponding to an absorption length of 67 m) close to the one of optically pure water and it does not show seasonal variation.

  1. Error decomposition and estimation of inherent optical properties.

    PubMed

    Salama, Mhd Suhyb; Stein, Alfred

    2009-09-10

    We describe a methodology to quantify and separate the errors of inherent optical properties (IOPs) derived from ocean-color model inversion. Their total error is decomposed into three different sources, namely, model approximations and inversion, sensor noise, and atmospheric correction. Prior information on plausible ranges of observation, sensor noise, and inversion goodness-of-fit are employed to derive the posterior probability distribution of the IOPs. The relative contribution of each error component to the total error budget of the IOPs, all being of stochastic nature, is then quantified. The method is validated with the International Ocean Colour Coordinating Group (IOCCG) data set and the NASA bio-Optical Marine Algorithm Data set (NOMAD). The derived errors are close to the known values with correlation coefficients of 60-90% and 67-90% for IOCCG and NOMAD data sets, respectively. Model-induced errors inherent to the derived IOPs are between 10% and 57% of the total error, whereas atmospheric-induced errors are in general above 43% and up to 90% for both data sets. The proposed method is applied to synthesized and in situ measured populations of IOPs. The mean relative errors of the derived values are between 2% and 20%. A specific error table to the Medium Resolution Imaging Spectrometer (MERIS) sensor is constructed. It serves as a benchmark to evaluate the performance of the atmospheric correction method and to compute atmospheric-induced errors. Our method has a better performance and is more appropriate to estimate actual errors of ocean-color derived products than the previously suggested methods. Moreover, it is generic and can be applied to quantify the error of any derived biogeophysical parameter regardless of the used derivation. PMID:19745859

  2. REDUCTION OF INHERENT MERCURY EMISSIONS IN PC COMBUSTION

    SciTech Connect

    John C. Kramlich; Rebecca N. Sliger; David J. Going

    1999-08-06

    Mercury emission compliance presents one of the major potential challenges raised by the 1990 Clean Air Act Amendments. Simple ways of controlling emissions have not been identified. The variability in the field data suggest that inherent mercury emissions may be reduced if the source of this inherent capture can be identified and controlled. The key mechanisms appear to involve the oxidation of mercury to Hg{sup 2}, generally producing the more reactive HgCl{sub 2}, followed by its capture by certain components of the fly ash or char, or in the air pollution control equipment. This research focuses on identifying the rate-limiting steps associated with the oxidation step. Work in this reporting period focused on testing of the kinetic mechanism reported in the previous semiannual report, and the interpretation of data (both ours and literature). This model yields good qualitative agreement with the data and indicates that mercury oxidation occurs during the thermal quench of the combustion gases. The model also suggests that atomic chlorine is the key oxidizing species. The oxidation is limited to a temperature window between 700-400 C that is defined by the overlap of (1) a region of significant superequilibrium Cl concentration, and (2) a region where oxidized mercury is favored by equilibrium. Above 700 C reverse reactions effectively limit oxidized mercury concentrations. Below 400 C, atomic chlorine concentrations are too low to support further oxidation. The implication of these results are that homogeneous oxidation is governed primarily by (1) HCl concentration, (2) quench rate, and (3) background gas composition. Work conducted under the present grant has been the subject of one journal paper that was accepted for publication during the reporting period (Sliger et al., 1999).

  3. Development of LMR physics technology in the United States

    SciTech Connect

    Hemmig, P.B. )

    1990-01-01

    Reactor physics technology for liquid-metal reactor (LMR) applications has been developed through a wide range of research activities carried out by US National laboratory, industrial, and university organizations.These were focused on the design of the Experimental Breeder Reactor II (EBR-II), Fast Flux Test Facility (FFTF), Clinch River Breeder Reactor, large-scale prototype breeder, and more recently on the Integral Fast Reactor, and Power Reactor Inherently Safe Module modular reactor concepts. Significant advancements are noted in the accuracy and economics of computational methodology, the quality of the basic nuclear data used for LMR design, and the quality of integral measurements used to support design and licensing activities. Cooperative efforts among US organizations have been the key to many advances. The systematic application of covariance data files for both integral and differential data contributes to further improvements in LMR core design technology. Since advanced LMRs can potentially provide a major fraction of electric power over the next millenium, LMR technology development is worthy of the best efforts. The major goals are reasonable construction costs, a high degree of natural safety, good operational reliability, and an economical, environmentally attractive fuel cycle. The successful operations of FFTF and EBR-II and the progress in reactor physics in recent years are good indications one can meet the challenge of introducing advanced LMRs.

  4. Hand Safety

    MedlinePlus

    ... en gatillo See More... Hand Anatomy Hand Safety Fireworks Safety Lawnmower Safety Snowblower safety Pumpkin Carving Gardening ... en gatillo See More... Hand Anatomy Hand Safety Fireworks Safety Lawnmower Safety Snowblower safety Pumpkin Carving Gardening ...

  5. Hand Safety

    MedlinePlus

    ... Fireworks Safety Lawnmower Safety Snowblower safety Pumpkin Carving Gardening Safety Turkey Carving Removing a Ring Español Artritis ... Fireworks Safety Lawnmower Safety Snowblower safety Pumpkin Carving Gardening Safety Turkey Carving Removing a Ring Español Artritis ...

  6. Impurities in Silicon Nanocrystals: The intentional and the inherent

    NASA Astrophysics Data System (ADS)

    Rowe, David J.

    Silicon nanocrystals (SiNCs) have become an important class of materials in the fields of photovoltaics, thermoelectrics, lighting, and medicine. Impurities within SiNCs dramatically alter the electrical and optical properties of the host material, whether the impurity is intentionally added in an attempt to manipulate properties, or is inherent to the material and its natural state. Despite such remarkable changes, impurity incorporation within SiNCs remains poorly understood, since concepts applied to understanding impurities in bulk materials may not completely translate to nanomaterials. Understanding the effect of SiNC impurities requires new technologies to produce materials suitable for study combined with new insights to expound the differences in the nanoscale physics. Nonthermal plasma-assisted gas-phase synthesis provides an excellent route to producing and investigating impurities within SiNCs due to the unique chemical reaction environment of the plasma. The robustness of such a technique allows for the production of very pure SiNCs or SiNCs with added impurities simply by adding different chemicals to the plasma. The chapters in this document focus on the effect that different impurities have on the properties of SiNCs. Chapter 2 focuses on heavily P-doped SiNCs exhibiting the first known observation of a unique electrical and optical property known as localized surface plasmon resonance (LSPR) within free-standing SiNCs. Chapter 3 explains the synthesis of B- and P-doped SiGeNC alloys and their deposition into thin films for thermoelectric applications. Chapter 4 highlights research which uses P-doped SiNCs to form emitter layers for pn-junction type solar cells, including device fabrication and optical characterization. Chapter 5 examines inherent impurities in the form of dangling bond defects which may be responsible for the quenching of SiNC photoluminescence, and their evolution during the process of air-ambient oxidation. Several appendices at

  7. Communicating uncertainty: managing the inherent probabilistic character of hazard estimates

    NASA Astrophysics Data System (ADS)

    Albarello, Dario

    2013-04-01

    Science is much more fixing the limits of our knowledge about possible occurrences than the identification of any "truth". This is particularly true when scientific statements concern prediction of natural phenomena largely exceeding the laboratory scale as in the case of seismogenesis. In these cases, many scenarios about future occurrences result possible (plausible) and the contribution of scientific knowledge (based on the available knowledge about underlying processes or the phenomenological studies) mainly consists in attributing to each scenario a different level of likelihood (probability). In other terms, scientific predictions in the field of geosciences (hazard assessment) are inherently probabilistic. However, despite of this, many scientist (seismologists, etc.) in communicating their position in public debates tend to stress the " truth" of their statements against the fancy character of pseudo-scientific assertions: stronger is the opposition of science and pseudo-science, more hidden becomes the probabilistic character of scientific statements. The problem arises when this kind of "probabilistic" knowledge becomes the basis of any political action (e.g., to impose expensive form of risk reducing activities): in these cases the lack of any definitive "truth" requires a direct assumption of responsibility by the relevant decider (being the single citizen or the legitimate expression of a larger community) to choose among several possibilities (however characterized by different levels of likelihood). In many cases, this can be uncomfortable and strong is the attitude to delegate to the scientific counterpart the responsibility of these decisions. This "transfer" from the genuine political field to an improper scientific context is also facilitated by the lack of a diffuse culture of "probability" outside the scientific community (and in many cases inside also). This is partially the effect of the generalized adoption (by media and scientific

  8. Amine-functionalized polypyrrole: Inherently cell adhesive conducting polymer.

    PubMed

    Lee, Jae Y; Schmidt, Christine E

    2015-06-01

    Electrically conducting polymers (CPs) have been recognized as novel biomaterials that can electrically communicate with biological systems. For their tissue engineering applications, CPs have been modified to promote cell adhesion for improved interactions between biomaterials and cells/tissues. Conventional approaches to improve cell adhesion involve the surface modification of CPs with biomolecules, such as physical adsorption of cell adhesive proteins and polycationic polymers, or their chemical immobilization; however, these approaches require additional multiple modification steps with expensive biomolecules. In this study, as a simple and effective alternative to such additional biomolecule treatment, we synthesized amine-functionalized polypyrrole (APPy) that inherently presents cell adhesion-supporting positive charges under physiological conditions. The synthesized APPy provides electrical activity in a moderate range and a hydrophilic surface compared to regular polypyrrole (PPy) homopolymers. Under both serum and serum-free conditions, APPy exhibited superior attachment of human dermal fibroblasts and Schwann cells compared to PPy homopolymer controls. Moreover, Schwann cell adhesion onto the APPy copolymer was at least similar to that on poly-l-lysine treated PPy controls. Our results indicate that amine-functionalized CP substrates will be useful to achieve good cell adhesion and potentially electrically stimulate various cells. In addition, amine functionality present on CPs can further serve as a novel and flexible platform to chemically tether various bioactive molecules, such as growth factors, antibodies, and chemical drugs. PMID:25294089

  9. Managing inherent complexity for sustainable walleye fisheries in Lake Erie

    USGS Publications Warehouse

    Roseman, Edward F.; Drouin, Richard; Gaden, Marc; Knight, Roger; Tyson, Jeff; Zhao, Yingming

    2012-01-01

    In Lake Erie, Walleye (Sander vitreus vitreus) is king. The naturally occurring species is the foundation of commercial fishing operations on the Canadian side of the lake and is a much-prized sport fish on the American side. Management of Lake Erie walleye fisheries is complex and takes place in an inter-jurisdictional setting composed of resource agencies from the states of Michigan (MDNR), Ohio (ODNR), Pennsylvania (PFBC), and New York (NYDEC) and the province of Ontario (OMNR). The complexity of walleye management is exacerbated by interactions among environmental and ecological changes in Lake Erie, complex life-history characteristics of the species, public demand for walleye, and cultural/governance differences among managing groups and their respective constituents. Success of future management strategies will largely hinge upon our ability to understand these inherent complexities and to employ tactics that successfully accommodate stock productivity and human demand in a highly dynamic environment. In this report, we review the history of Lake Erie walleye management, outline the multi-jurisdictional process for international management of walleye, and discuss strategies to address challenges facing managers.

  10. Increase of inherent protection level in spent nuclear fuel

    SciTech Connect

    Krasnobaev, A.; Kryuchkov, E.; Glebov, V.

    2006-07-01

    The paper is devoted to upgrading inherent proliferation protection of fissionable nuclear materials (FNM). Some possibilities were investigated to form high radiation barrier inside spent fuel assemblies (SFA) discharged from power reactors of VVER-1000 type and research reactors of IRT type. The radiation barrier is estimated in the terms of rate of equivalent dose (RED) at 30-cm distance from SFA. The values of RED were calculated with application of the computer code package SCALE 4.3. The paper considers the criteria adopted for estimation of FNM proliferation resistance. The paper presents numerical results on a component-wise analysis of the radiation barrier in SFA from reactors of VVER-1000 and IRT type and on capability of various radionuclides to prolong action of the radiation barrier. Isotopic admixtures were selected and amounts of these admixtures were evaluated for significant prolongation of the radiation barrier action at the levels of the radiation standards used for estimation of FNM proliferation resistance. The paper considers vulnerability of the radiation barriers in respect to thermal processing of spent fuel. (authors)

  11. Inherent structure versus geometric metric for state space discretization.

    PubMed

    Liu, Hanzhong; Li, Minghai; Fan, Jue; Huo, Shuanghong

    2016-05-30

    Inherent structure (IS) and geometry-based clustering methods are commonly used for analyzing molecular dynamics trajectories. ISs are obtained by minimizing the sampled conformations into local minima on potential/effective energy surface. The conformations that are minimized into the same energy basin belong to one cluster. We investigate the influence of the applications of these two methods of trajectory decomposition on our understanding of the thermodynamics and kinetics of alanine tetrapeptide. We find that at the microcluster level, the IS approach and root-mean-square deviation (RMSD)-based clustering method give totally different results. Depending on the local features of energy landscape, the conformations with close RMSDs can be minimized into different minima, while the conformations with large RMSDs could be minimized into the same basin. However, the relaxation timescales calculated based on the transition matrices built from the microclusters are similar. The discrepancy at the microcluster level leads to different macroclusters. Although the dynamic models established through both clustering methods are validated approximately Markovian, the IS approach seems to give a meaningful state space discretization at the macrocluster level in terms of conformational features and kinetics. © 2016 Wiley Periodicals, Inc. PMID:26915811

  12. Experimental quantum control landscapes: Inherent monotonicity and artificial structure

    SciTech Connect

    Roslund, Jonathan; Rabitz, Herschel

    2009-07-15

    Unconstrained searches over quantum control landscapes are theoretically predicted to generally exhibit trap-free monotonic behavior. This paper makes an explicit experimental demonstration of this intrinsic monotonicity for two controlled quantum systems: frequency unfiltered and filtered second-harmonic generation (SHG). For unfiltered SHG, the landscape is randomly sampled and interpolation of the data is found to be devoid of landscape traps up to the level of data noise. In the case of narrow-band-filtered SHG, trajectories are taken on the landscape to reveal a lack of traps. Although the filtered SHG landscape is trap free, it exhibits a rich local structure. A perturbation analysis around the top of these landscapes provides a basis to understand their topology. Despite the inherent trap-free nature of the landscapes, practical constraints placed on the controls can lead to the appearance of artificial structure arising from the resultant forced sampling of the landscape. This circumstance and the likely lack of knowledge about the detailed local landscape structure in most quantum control applications suggests that the a priori identification of globally successful (un)constrained curvilinear control variables may be a challenging task.

  13. A gradient field defeats the inherent repulsion between magnetic nanorods

    PubMed Central

    Gu, Yu; Burtovyy, Ruslan; Custer, John; Luzinov, Igor; Kornev, Konstantin G.

    2014-01-01

    When controlling the assembly of magnetic nanorods and chains of magnetic nanoparticles, it is extremely challenging to bring them together side by side while keeping a desired spacing between their axes. We show that this challenge can be successfully resolved by using a non-uniform magnetic field that defeats an inherent repulsion between nanorods. Nickel nanorods were suspended in a viscous film and a non-uniform field was used to control their placement. The in-plane movement of nanorods was tracked with a high-speed camera and a detailed image analysis was conducted to quantitatively characterize the behaviour of the nanorods. The analysis focused on the behaviour of a pair of neighbour nanorods, and a corresponding dynamic model was formulated and investigated. The complex two-dimensional dynamics of a nanorod pair was analysed analytically and numerically, and a phase portrait was constructed. Using this phase portrait, we classified the nanorod behaviour and revealed the experimental conditions in which nanorods could be placed side by side. Dependence of the distance between a pair of neighbour nanorods on physical parameters was analysed. With the aid of the proposed theory, one can build different lattices and control their spacing by applying different field gradients. PMID:26064550

  14. Making appropriation 'stick': stabilizing politics in an 'inherently feminist' tool.

    PubMed

    Hasson, Katie Ann

    2012-10-01

    This article examines how feminist politics are made to 'stick' to appropriated technologies in the context of a contemporary feminist women's health clinic in the US. Feminist clinics such as 'FemHealth', founded as part of 1970s women's health movements, put medical tools and knowledge into lay women's hands, making the appropriation of medical technologies a centerpiece of their political project. In the process, they rejected the authority of physicians and gave new politicized meanings to the tools they claimed as their own. As lay healthworkers at FemHealth continued the project of appropriation, they also continued to negotiate their dependence on physicians to perform tasks that required a medical license. Drawing on participant observation and interviews with healthworkers, I argue that struggles over the role and authority of physicians in this clinic play out through debates over two similar and competing tools used in the abortion procedure: the single-tooth tenaculum and the cervical stabilizer. Many healthworkers invested in the stabilizer as 'inherently feminist' in hopes that it would maintain its politics even when passed into physicians' hands. While appropriation depends on the ability of users to alter a technology's meanings, actors may feel invested in the new politics taken on by appropriated tools and work towards making those meanings persist, or 'stick'. PMID:23189608

  15. External noise control in inherently stochastic biological systems.

    PubMed

    Zheng, Likun; Chen, Meng; Nie, Qing

    2012-11-01

    Biological systems are often subject to external noise from signal stimuli and environmental perturbations, as well as noises in the intracellular signal transduction pathway. Can different stochastic fluctuations interact to give rise to new emerging behaviors? How can a system reduce noise effects while still being capable of detecting changes in the input signal? Here, we study analytically and computationally the role of nonlinear feedback systems in controlling external noise with the presence of large internal noise. In addition to noise attenuation, we analyze derivatives of Fano factor to study systems' capability of differentiating signal inputs. We find effects of internal noise and external noise may be separated in one slow positive feedback loop system; in particular, the slow loop can decrease external noise and increase robustness of signaling with respect to fluctuations in rate constants, while maintaining the signal output specific to the input. For two feedback loops, we demonstrate that the influence of external noise mainly depends on how the fast loop responds to fluctuations in the input and the slow loop plays a limited role in determining the signal precision. Furthermore, in a dual loop system of one positive feedback and one negative feedback, a slower positive feedback always leads to better noise attenuation; in contrast, a slower negative feedback may not be more beneficial. Our results reveal interesting stochastic effects for systems containing both extrinsic and intrinsic noises, suggesting novel noise filtering strategies in inherently stochastic systems. PMID:23213267

  16. Tensions inherent in the evolving role of the infection preventionist

    PubMed Central

    Conway, Laurie J.; Raveis, Victoria H.; Pogorzelska-Maziarz, Monika; Uchida, May; Stone, Patricia W.; Larson, Elaine L.

    2014-01-01

    Background The role of infection preventionists (IPs) is expanding in response to demands for quality and transparency in health care. Practice analyses and survey research have demonstrated that IPs spend a majority of their time on surveillance and are increasingly responsible for prevention activities and management; however, deeper qualitative aspects of the IP role have rarely been explored. Methods We conducted a qualitative content analysis of in-depth interviews with 19 IPs at hospitals throughout the United States to describe the current IP role, specifically the ways that IPs effect improvements and the facilitators and barriers they face. Results The narratives document that the IP role is evolving in response to recent changes in the health care landscape and reveal that this progression is associated with friction and uncertainty. Tensions inherent in the evolving role of the IP emerged from the interviews as 4 broad themes: (1) expanding responsibilities outstrip resources, (2) shifting role boundaries create uncertainty, (3) evolving mechanisms of influence involve trade-offs, and (4) the stress of constant change is compounded by chronic recurring challenges. Conclusion Advances in implementation science, data standardization, and training in leadership skills are needed to support IPs in their evolving role. PMID:23880116

  17. Energy storage inherent in large tidal turbine farms.

    PubMed

    Vennell, Ross; Adcock, Thomas A A

    2014-06-01

    While wind farms have no inherent storage to supply power in calm conditions, this paper demonstrates that large tidal turbine farms in channels have short-term energy storage. This storage lies in the inertia of the oscillating flow and can be used to exceed the previously published upper limit for power production by currents in a tidal channel, while simultaneously maintaining stronger currents. Inertial storage exploits the ability of large farms to manipulate the phase of the oscillating currents by varying the farm's drag coefficient. This work shows that by optimizing how a large farm's drag coefficient varies during the tidal cycle it is possible to have some flexibility about when power is produced. This flexibility can be used in many ways, e.g. producing more power, or to better meet short predictable peaks in demand. This flexibility also allows trading total power production off against meeting peak demand, or mitigating the flow speed reduction owing to power extraction. The effectiveness of inertial storage is governed by the frictional time scale relative to either the duration of a half tidal cycle or the duration of a peak in power demand, thus has greater benefits in larger channels. PMID:24910516

  18. Solving Optimal Control Problems by Exploiting Inherent Dynamical Systems Structures

    NASA Astrophysics Data System (ADS)

    Flaßkamp, Kathrin; Ober-Blöbaum, Sina; Kobilarov, Marin

    2012-08-01

    Computing globally efficient solutions is a major challenge in optimal control of nonlinear dynamical systems. This work proposes a method combining local optimization and motion planning techniques based on exploiting inherent dynamical systems structures, such as symmetries and invariant manifolds. Prior to the optimal control, the dynamical system is analyzed for structural properties that can be used to compute pieces of trajectories that are stored in a motion planning library. In the context of mechanical systems, these motion planning candidates, termed primitives, are given by relative equilibria induced by symmetries and motions on stable or unstable manifolds of e.g. fixed points in the natural dynamics. The existence of controlled relative equilibria is studied through Lagrangian mechanics and symmetry reduction techniques. The proposed framework can be used to solve boundary value problems by performing a search in the space of sequences of motion primitives connected using optimized maneuvers. The optimal sequence can be used as an admissible initial guess for a post-optimization. The approach is illustrated by two numerical examples, the single and the double spherical pendula, which demonstrates its benefit compared to standard local optimization techniques.

  19. Energy storage inherent in large tidal turbine farms

    PubMed Central

    Vennell, Ross; Adcock, Thomas A. A.

    2014-01-01

    While wind farms have no inherent storage to supply power in calm conditions, this paper demonstrates that large tidal turbine farms in channels have short-term energy storage. This storage lies in the inertia of the oscillating flow and can be used to exceed the previously published upper limit for power production by currents in a tidal channel, while simultaneously maintaining stronger currents. Inertial storage exploits the ability of large farms to manipulate the phase of the oscillating currents by varying the farm's drag coefficient. This work shows that by optimizing how a large farm's drag coefficient varies during the tidal cycle it is possible to have some flexibility about when power is produced. This flexibility can be used in many ways, e.g. producing more power, or to better meet short predictable peaks in demand. This flexibility also allows trading total power production off against meeting peak demand, or mitigating the flow speed reduction owing to power extraction. The effectiveness of inertial storage is governed by the frictional time scale relative to either the duration of a half tidal cycle or the duration of a peak in power demand, thus has greater benefits in larger channels. PMID:24910516

  20. Prediction of stainless steel activation in experimental breeder reactor 2 (EBR-II) reflector and blanket subassemblies

    SciTech Connect

    Bunde, K.A.

    1996-12-31

    Stainless steel structural components in nuclear reactors become radioactive wastes when no longer useful. Prior to disposal, certain physical attributes must be analyzed. These attributes include structural integrity, chemical stability, and the radioactive material content among others. The focus of this work is the estimation of the radioactive material content of stainless steel wastes from a research reactor operated by Argonne National Laboratory.

  1. Understanding the Spatiotemporal Variability of Inherent Water Use Efficiency

    NASA Astrophysics Data System (ADS)

    Boese, Sven; Jung, Martin; Carvalhais, Nuno; Reichstein, Markus

    2015-04-01

    The global carbon and water cycles are coupled via plant physiology. However, the resulting spatial and temporal covariability of both fluxes on a global scale lacks sufficient understanding. This is required to estimate the impact of atmospheric drought on photosynthesis in water-limited ecosystems. Water use efficiency (WUE) is an essential ecosystem diagnostic defined as the ratio between gross primary productivity (GPP) and transpiration (T). WUE is known to vary with vapour-pressure deficit (VPD) and therefore also in time. The inherent water use efficiency (iWUE) accounts for the VPD effect on WUE and aims at representing a largely time-invariant ecosystem property. However, different ways of describing the functional response of iWUE to VPD are found in the literature. One established iWUE definition was proposed by Beer et al. (2009) and takes the form of iWUE = GPP--VPD- . T (1) A similar definition can be derived from stomatal conductance theories such as Katul et al. (2010) and takes the form of √ -- GPP---VPD- iWUE = T . (2) Here, we use eddy covariance measurements from the FLUXNET database to evaluate both approaches for a globally representative set of biomes including tropical, temperate and semi-arid ecosystems. Testing both definitions in a model-data fusion setup indicated that (2) is more consistent with FLUXNET observations than (1). However, there still remains considerable temporal variability of iWUE which is linked to seasonal changes in VPD. To explore up to which extent the temporal variability of iWUE may be related to the prescribed functional responses to VPD, we treated the exponent of VPD as a global parameter, here termed γ. When γ = 1 the functional response is equivalent to (1), while when γ = 0.5 it corresponds to formulation of model (2)). The global estimate was found to be significantly lower than 0.5, which would have been expected from stomatal conductance theory at leaf level. We assessed whether adding γ as site

  2. Nuclear safety

    NASA Technical Reports Server (NTRS)

    Buden, D.

    1991-01-01

    Topics dealing with nuclear safety are addressed which include the following: general safety requirements; safety design requirements; terrestrial safety; SP-100 Flight System key safety requirements; potential mission accidents and hazards; key safety features; ground operations; launch operations; flight operations; disposal; safety concerns; licensing; the nuclear engine for rocket vehicle application (NERVA) design philosophy; the NERVA flight safety program; and the NERVA safety plan.

  3. SSC Safety Review Document

    SciTech Connect

    Toohig, T.E.

    1988-11-01

    The safety strategy of the Superconducting Super Collider (SSC) Central Design Group (CDG) is to mitigate potential hazards to personnel, as far as possible, through appropriate measures in the design and engineering of the facility. The Safety Review Document identifies, on the basis of the Conceptual Design Report (CDR) and related studies, potential hazards inherent in the SSC project independent of its site. Mitigative measures in the design of facilities and in the structuring of laboratory operations are described for each of the hazards identified.

  4. Inherent structures of phase-separating binary mixtures: Nucleation, spinodal decomposition, and pattern formation

    NASA Astrophysics Data System (ADS)

    Sarkar, Sarmistha; Bagchi, Biman

    2011-03-01

    An energy landscape view of phase separation and nonideality in binary mixtures is developed by exploring their potential energy landscape (PEL) as functions of temperature and composition. We employ molecular dynamics simulations to study a model that promotes structure breaking in the solute-solvent parent binary liquid, at low temperatures. The PEL of the system captures the potential energy distribution of the inherent structures (IS) of the system and is obtained by removing the kinetic energy (including that of intermolecular vibrations). The broader distribution of the inherent structure energy for structure breaking liquid than that of the structure making liquid demonstrates the larger role of entropy in stabilizing the parent liquid of the structure breaking type of binary mixtures. At high temperature, although the parent structure of the structure breaking binary mixture is homogenous, the corresponding inherent structure is found to be always phase separated, with a density pattern that exhibits marked correlation with the energy of its inherent structure. Over a broad range of intermediate inherent structure energy, bicontinuous phase separation prevails with interpenetrating stripes as signatures of spinodal decomposition. At low inherent structure energy, the structure is largely phase separated with one interface where as at high inherent structure energy we find nucleation type growth. Interestingly, at low temperature, the average inherent structure energy () exhibits a drop with temperature which signals the onset of crystallization in one of the phases while the other remains in the liquid state. The nonideal composition dependence of viscosity is anticorrelated with average inherent structure energy.

  5. Querying Safety Cases

    NASA Technical Reports Server (NTRS)

    Denney, Ewen W.; Naylor, Dwight; Pai, Ganesh

    2014-01-01

    Querying a safety case to show how the various stakeholders' concerns about system safety are addressed has been put forth as one of the benefits of argument-based assurance (in a recent study by the Health Foundation, UK, which reviewed the use of safety cases in safety-critical industries). However, neither the literature nor current practice offer much guidance on querying mechanisms appropriate for, or available within, a safety case paradigm. This paper presents a preliminary approach that uses a formal basis for querying safety cases, specifically Goal Structuring Notation (GSN) argument structures. Our approach semantically enriches GSN arguments with domain-specific metadata that the query language leverages, along with its inherent structure, to produce views. We have implemented the approach in our toolset AdvoCATE, and illustrate it by application to a fragment of the safety argument for an Unmanned Aircraft System (UAS) being developed at NASA Ames. We also discuss the potential practical utility of our query mechanism within the context of the existing framework for UAS safety assurance.

  6. A case for inherent geometric and geodetic accuracy in remotely sensed VNIR and SWIR imaging products

    NASA Technical Reports Server (NTRS)

    Driver, J. M.

    1982-01-01

    Significant aberrations can occur in acquired images which, unless compensated on board the spacecraft, can seriously impair throughput and timeliness for typical Earth observation missions. Conceptual compensations options are advanced to enable acquisition of images with inherent geometric and geodetic accuracy. Research needs are identified which, when implemented, can provide inherently accurate images. Agressive pursuit of these research needs is recommended.

  7. 16 CFR 1211.13 - Inherent force activated secondary door sensors.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... 16 Commercial Practices 2 2011-01-01 2011-01-01 false Inherent force activated secondary door... § 1211.13 Inherent force activated secondary door sensors. (a) Normal operation test. (1) A force... when the door applies a 15 pound (66.7 N) or less force in the down or closing direction and when...

  8. 16 CFR 1211.13 - Inherent force activated secondary door sensors.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... 16 Commercial Practices 2 2013-01-01 2013-01-01 false Inherent force activated secondary door... § 1211.13 Inherent force activated secondary door sensors. (a) Normal operation test. (1) A force... when the door applies a 15 pound (66.7 N) or less force in the down or closing direction and when...

  9. 16 CFR 1211.13 - Inherent force activated secondary door sensors.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... 16 Commercial Practices 2 2014-01-01 2014-01-01 false Inherent force activated secondary door... § 1211.13 Inherent force activated secondary door sensors. (a) Normal operation test. (1) A force... when the door applies a 15 pound (66.7 N) or less force in the down or closing direction and when...

  10. 16 CFR 1211.13 - Inherent force activated secondary door sensors.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... 16 Commercial Practices 2 2012-01-01 2012-01-01 false Inherent force activated secondary door... § 1211.13 Inherent force activated secondary door sensors. (a) Normal operation test. (1) A force... when the door applies a 15 pound (66.7 N) or less force in the down or closing direction and when...

  11. 40 CFR 88.311-93 - Emissions standards for Inherently Low-Emission Vehicles.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 40 Protection of Environment 21 2013-07-01 2013-07-01 false Emissions standards for Inherently Low-Emission Vehicles. 88.311-93 Section 88.311-93 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) AIR PROGRAMS (CONTINUED) CLEAN-FUEL VEHICLES Clean-Fuel Fleet Program § 88.311-93 Emissions standards for Inherently...

  12. Effects of inherent alkali and alkaline earth metallic species on biomass pyrolysis at different temperatures.

    PubMed

    Hu, Song; Jiang, Long; Wang, Yi; Su, Sheng; Sun, Lushi; Xu, Boyang; He, Limo; Xiang, Jun

    2015-09-01

    This work aimed to investigate effects of inherent alkali and alkaline earth metallic species (AAEMs) on biomass pyrolysis at different temperatures. The yield of CO, H2 and C2H4 was increased and that of CO2 was suppressed with increasing temperature. Increasing temperature could also promote depolymerization and aromatization reactions of active tars, forming heavier polycyclic aromatic hydrocarbons, leading to decrease of tar yields and species diversity. Diverse performance of inherent AAEMs at different temperatures significantly affected the distribution of pyrolysis products. The presence of inherent AAEMs promoted water-gas shift reaction, and enhanced the yield of H2 and CO2. Additionally, inherent AAEMs not only promoted breakage and decarboxylation/decarbonylation reaction of thermally labile hetero atoms of the tar but also enhanced thermal decomposing of heavier aromatics. Inherent AAEMs could also significantly enhance the decomposition of levoglucosan, and alkaline earth metals showed greater effect than alkali metals. PMID:26005925

  13. [The sorting of recyclable waste and the variables inherent to the process: a case study in a cooperative].

    PubMed

    de Souza, Renato Luvizoto Rodrigues; Fontes, Andréa Regina Martins; Salomão, Silvana

    2014-10-01

    Informal labor with recyclable materials is marked by social exclusion and discrimination, besides this activity being conducted in unsanitary conditions. The literature suggests that the problems associated with the sorting of recyclable waste are associated with lack of structure, contact with the "garbage", lack of government support, lack of training, lack of safety equipment, among others. The scope of this paper is to describe the process of sorting recyclable waste in a cooperative in França in the state of São Paulo. The specific objective was to identify the variables inherent to the process and investigate how workers adjust their work schedules to deal with these variables. The research method used is the case study with an operationalized ergonomic approach at some stages of the ergonomic analysis of work. Exploratory visits, indirect observations and semi-structured interviews were conducted. The results showed that the variables inherent to the process require that workers perform timely management sessions, which can be either collective or individual, though this invariably results in overload in the workplace, either by speeding up the work output or by demanding the increased concentration of those involved. PMID:25272127

  14. Inherent structures of phase-separating binary mixtures: nucleation, spinodal decomposition, and pattern formation.

    PubMed

    Sarkar, Sarmistha; Bagchi, Biman

    2011-03-01

    An energy landscape view of phase separation and nonideality in binary mixtures is developed by exploring their potential energy landscape (PEL) as functions of temperature and composition. We employ molecular dynamics simulations to study a model that promotes structure breaking in the solute-solvent parent binary liquid, at low temperatures. The PEL of the system captures the potential energy distribution of the inherent structures (IS) of the system and is obtained by removing the kinetic energy (including that of intermolecular vibrations). The broader distribution of the inherent structure energy for structure breaking liquid than that of the structure making liquid demonstrates the larger role of entropy in stabilizing the parent liquid of the structure breaking type of binary mixtures. At high temperature, although the parent structure of the structure breaking binary mixture is homogenous, the corresponding inherent structure is found to be always phase separated, with a density pattern that exhibits marked correlation with the energy of its inherent structure. Over a broad range of intermediate inherent structure energy, bicontinuous phase separation prevails with interpenetrating stripes as signatures of spinodal decomposition. At low inherent structure energy, the structure is largely phase separated with one interface where as at high inherent structure energy we find nucleation type growth. Interestingly, at low temperature, the average inherent structure energy () exhibits a drop with temperature which signals the onset of crystallization in one of the phases while the other remains in the liquid state. The nonideal composition dependence of viscosity is anticorrelated with average inherent structure energy. PMID:21517506

  15. Long range stress correlations in the inherent structures of liquids at rest

    NASA Astrophysics Data System (ADS)

    Chowdhury, Sadrul; Abraham, Sneha; Hudson, Toby; Harrowell, Peter

    2016-03-01

    Simulation studies of the atomic shear stress in the local potential energy minima (inherent structures) are reported for binary liquid mixtures in 2D and 3D. These inherent structure stresses are fundamental to slow stress relaxation and high viscosity in supercooled liquids. We find that the atomic shear stress in the inherent structures (IS's) of both liquids at rest exhibits slowly decaying anisotropic correlations. We show that the stress correlations contribute significantly to the variance of the total shear stress of the IS configurations and consider the origins of the anisotropy and spatial extent of the stress correlations.

  16. Data package addendum for COBRA-1A2 life extension to 400 EFPD

    SciTech Connect

    Hecht, S.L.; Ermi, A.M.

    1994-08-29

    The COBRA-1A experiment was originally designed for irradiations up to 350 effective full power days (EFPD) in EBR-II. Three of the seven B7A test capsules were discharged after 88.6 EFPD (COBRA-1A1; EBR-II designation X516), while the remaining four capsules continued to be irradiated to a goal exposure of 300 EFPD (COBRA-1A2; EBR-II designation X516A). However, it was recently decided that COBRA-1A2 was to remain in the reactor during Run 170, giving and nominal end-of-life (EOL) exposure of 375 EFPD. Since the revised test exposure exceeds the design basis given in supporting analyses, amended analyses are provided herein, giving the technical bases for the extended irradiation. This report describes the safety analysis for the extension of the COBRA-1A2 test (X516A) to 400 effective full power days in FBR-II.

  17. The effects of error management climate and safety communication on safety: a multi-level study.

    PubMed

    Cigularov, Konstantin P; Chen, Peter Y; Rosecrance, John

    2010-09-01

    Work in the construction industry is considered inherently dangerous, despite the technological improvements regarding the safety of work conditions and equipment. To address the urgent need to identify organizational predictors of safety performance and outcomes among construction workers, the present study examined multi-level effects of two important indicators of safety climate, namely contractor error management climate and worker safety communication, on safety behavior, injury, and pain among union construction workers. Data were collected from 235 union construction workers employed by 15 contractors in Midwest and Northwest regions of the United States. Results revealed significant main effects for safety communication and error management climate on safety behaviors and pain, but not on injuries. Our findings suggest that positive safety communication and error management climate are important contributors to improving workplace safety. Specific implications of these results for organizational safety research and practice are discussed. PMID:20538106

  18. Is the Inherent Potential of Maize Roots Efficient for Soil Phosphorus Acquisition?

    PubMed Central

    Deng, Yan; Chen, Keru; Teng, Wan; Zhan, Ai; Tong, Yiping; Feng, Gu; Cui, Zhenling; Zhang, Fusuo; Chen, Xinping

    2014-01-01

    Sustainable agriculture requires improved phosphorus (P) management to reduce the overreliance on P fertilization. Despite intensive research of root adaptive mechanisms for improving P acquisition, the inherent potential of roots for efficient P acquisition remains unfulfilled, especially in intensive agriculture, while current P management generally focuses on agronomic and environmental concerns. Here, we investigated how levels of soil P affect the inherent potential of maize (Zea mays L.) roots to obtain P from soil. Responses of root morphology, arbuscular mycorrhizal colonization, and phosphate transporters were characterized and related to agronomic traits in pot and field experiments with soil P supply from deficiency to excess. Critical soil Olsen-P level for maize growth approximated 3.2 mg kg−1, and the threshold indicating a significant environmental risk was about 15 mg kg−1, which represented the lower and upper levels of soil P recommended in current P management. However, most root adaptations involved with P acquisition were triggered when soil Olsen-P was below 10 mg kg−1, indicating a threshold for maximum root inherent potential. Therefore, to maintain efficient inherent potential of roots for P acquisition, we suggest that the target upper level of soil P in intensive agriculture should be reduced from the environmental risk threshold to the point maximizing the inherent potential of roots. PMID:24594677

  19. Is the inherent potential of maize roots efficient for soil phosphorus acquisition?

    PubMed

    Deng, Yan; Chen, Keru; Teng, Wan; Zhan, Ai; Tong, Yiping; Feng, Gu; Cui, Zhenling; Zhang, Fusuo; Chen, Xinping

    2014-01-01

    Sustainable agriculture requires improved phosphorus (P) management to reduce the overreliance on P fertilization. Despite intensive research of root adaptive mechanisms for improving P acquisition, the inherent potential of roots for efficient P acquisition remains unfulfilled, especially in intensive agriculture, while current P management generally focuses on agronomic and environmental concerns. Here, we investigated how levels of soil P affect the inherent potential of maize (Zea mays L.) roots to obtain P from soil. Responses of root morphology, arbuscular mycorrhizal colonization, and phosphate transporters were characterized and related to agronomic traits in pot and field experiments with soil P supply from deficiency to excess. Critical soil Olsen-P level for maize growth approximated 3.2 mg kg(-1), and the threshold indicating a significant environmental risk was about 15 mg kg(-1), which represented the lower and upper levels of soil P recommended in current P management. However, most root adaptations involved with P acquisition were triggered when soil Olsen-P was below 10 mg kg(-1), indicating a threshold for maximum root inherent potential. Therefore, to maintain efficient inherent potential of roots for P acquisition, we suggest that the target upper level of soil P in intensive agriculture should be reduced from the environmental risk threshold to the point maximizing the inherent potential of roots. PMID:24594677

  20. Experimental evidence for inherent Lévy search behaviour in foraging animals.

    PubMed

    Kölzsch, Andrea; Alzate, Adriana; Bartumeus, Frederic; de Jager, Monique; Weerman, Ellen J; Hengeveld, Geerten M; Naguib, Marc; Nolet, Bart A; van de Koppel, Johan

    2015-05-22

    Recently, Lévy walks have been put forward as a new paradigm for animal search and many cases have been made for its presence in nature. However, it remains debated whether Lévy walks are an inherent behavioural strategy or emerge from the animal reacting to its habitat. Here, we demonstrate signatures of Lévy behaviour in the search movement of mud snails (Hydrobia ulvae) based on a novel, direct assessment of movement properties in an experimental set-up using different food distributions. Our experimental data uncovered clusters of small movement steps alternating with long moves independent of food encounter and landscape complexity. Moreover, size distributions of these clusters followed truncated power laws. These two findings are characteristic signatures of mechanisms underlying inherent Lévy-like movement. Thus, our study provides clear experimental evidence that such multi-scale movement is an inherent behaviour rather than resulting from the animal interacting with its environment. PMID:25904671

  1. Experimental evidence for inherent Lévy search behaviour in foraging animals

    PubMed Central

    Kölzsch, Andrea; Alzate, Adriana; Bartumeus, Frederic; de Jager, Monique; Weerman, Ellen J.; Hengeveld, Geerten M.; Naguib, Marc; Nolet, Bart A.; van de Koppel, Johan

    2015-01-01

    Recently, Lévy walks have been put forward as a new paradigm for animal search and many cases have been made for its presence in nature. However, it remains debated whether Lévy walks are an inherent behavioural strategy or emerge from the animal reacting to its habitat. Here, we demonstrate signatures of Lévy behaviour in the search movement of mud snails (Hydrobia ulvae) based on a novel, direct assessment of movement properties in an experimental set-up using different food distributions. Our experimental data uncovered clusters of small movement steps alternating with long moves independent of food encounter and landscape complexity. Moreover, size distributions of these clusters followed truncated power laws. These two findings are characteristic signatures of mechanisms underlying inherent Lévy-like movement. Thus, our study provides clear experimental evidence that such multi-scale movement is an inherent behaviour rather than resulting from the animal interacting with its environment. PMID:25904671

  2. Summertime Safety

    MedlinePlus

    ... Violence & Safety Life Stages & Populations Travelers' Health Workplace Safety & Health Features Media Sign up for Features Get Email Updates ... Submit What's this? Submit Button Past Emails CDC Features Summertime Safety Recommend on Facebook Tweet Share Compartir The feature ...

  3. Drug Safety

    MedlinePlus

    ... over-the-counter drug. The FDA evaluates the safety of a drug by looking at Side effects ... clinical trials The FDA also monitors a drug's safety after approval. For you, drug safety means buying ...

  4. Safety Education.

    ERIC Educational Resources Information Center

    Daniels, James H.; And Others

    1980-01-01

    Five articles in this issue focus on safety education in agricultural laboratories. Topics discussed include teacher liability; elements of a safety instruction program; state and federal safety standards; ground fault current protection; and eye protection requirements and equipment. (SK)

  5. The inherence heuristic across development: systematic differences between children's and adults' explanations for everyday facts.

    PubMed

    Cimpian, Andrei; Steinberg, Olivia D

    2014-12-01

    The inherence heuristic is a basic cognitive process that supplies quick-and-easy answers to what are, in reality, incredibly complex questions about why the broad patterns of the world are as they are (Cimpian & Salomon, 2014-a, 2014-b). This explanatory heuristic satisfies the human need to understand, but it is also a source of bias because the heuristic relies too often on the (easily accessible) inherent features of the entities in the patterns being explained. Here, we investigated the developmental trajectory of this heuristic. Given that the cognitive resources that help override the typical output of the inherence heuristic are scarce in childhood, we hypothesized that the heuristic's output would be more broadly endorsed by children than by adults. Five experiments involving young children and adults (N=480) provided consistent support for this hypothesis. The first three experiments (Part I) investigated participants' explanations for broad patterns (e.g., fire trucks are red) and suggested that, consistent with our predictions, children were particularly likely to endorse inherence-based explanations. The last two experiments (Part II) investigated two intuitions that accompany the output of the inherence heuristic: namely, that the patterns being explained cannot be changed and are temporally stable. As predicted, participants' judgments on these dimensions showed the same developmental differences as the explanations investigated in Part I, with children being particularly likely to see patterns as inalterable and temporally stable. The developmental differences found across these five experiments suggest that children start out with a broad reliance on the explanatory output of the inherence heuristic, a reliance that narrows in scope to some extent as children develop. PMID:25291062

  6. The effects of inherent flaws on the time and rate dependent failure of adhesively bonded joints

    NASA Technical Reports Server (NTRS)

    Sancaktar, E.; Padgilwar, S.

    1982-01-01

    Inherent flaws, as well as the effects of rate and time, are shown by tests on viscoelastic adhesive-bonded single lap joints to be as critical in joint failure as environmental and stress concentration effects, with random inherent flaws and loading rate changes resulting in an up to 40% reduction in joint strength. It is also found that the asymptotic creep stress, below which no delayed failure may occur, may under creep loading be as much as 45% less than maximum adhesive strength. Attention is given to test results for the case of titanium-LARC-3 adhesive single-lap specimens.

  7. Inherently Chiral Calixarenes: Synthesis, Optical Resolution, Chiral Recognition and Asymmetric Catalysis

    PubMed Central

    Li, Shao-Yong; Xu, Yao-Wei; Liu, Jun-Min; Su, Cheng-Yong

    2011-01-01

    Inherently chiral calixarenes, whose chirality is based on the absence of a planar symmetry or an inversion center in the molecules as a whole through the asymmetric array of several achiral groups upon the three-dimensional calix-skeletons, are challenging and attractive chiral molecules, because of their potential in supramolecular chemistry. The synthesis and optical resolution of all varieties of inherently chiral calixarenes are systematically discussed and classified, and their applications in chiral recognition and asymmetric catalysis are thoroughly illustrated in this review. PMID:21339996

  8. Land-use/land-cover drives variation in the specific inherent optical properties of estuaries

    EPA Science Inventory

    Changes in land-use/land-cover (LULC) can impact the exports of optically and biogeochemically active constituents to estuaries. Specific inherent optical properties (SIOPs) of estuarine optically active constituents (OACs) are directly related to the composition of the OACs, and...

  9. Incorporating Risk Assessment and Inherently Safer Design Practices into Chemical Engineering Education

    ERIC Educational Resources Information Center

    Seay, Jeffrey R.; Eden, Mario R.

    2008-01-01

    This paper introduces, via case study example, the benefit of including risk assessment methodology and inherently safer design practices into the curriculum for chemical engineering students. This work illustrates how these tools can be applied during the earliest stages of conceptual process design. The impacts of decisions made during…

  10. Students' Perception of Live Lectures' Inherent Disadvantages

    ERIC Educational Resources Information Center

    Petrovic, Juraj; Pale, Predrag

    2015-01-01

    This paper aims to provide insight into various properties of live lectures from the perspective of sophomore engineering students. In an anonymous online survey conducted at the Faculty of Electrical Engineering and Computing, University of Zagreb, we investigated students' opinions regarding lecture attendance, inherent disadvantages of…

  11. Making the Grade: Describing Inherent Requirements for the Initial Teacher Education Practicum

    ERIC Educational Resources Information Center

    Sharplin, Elaine; Peden, Sanna; Marais, Ida

    2016-01-01

    This study explores the development, description, and illustration of inherent requirement (IR) statements to make explicit the requirements for performance on an initial teacher education (ITE) practicum. Through consultative group processes with stakeholders involved in ITE, seven IR domains were identified. From interviews with academics,…

  12. Legal Issues inherent in space shuttle operations. [reviewed by NASA Deputy General Counsel

    NASA Technical Reports Server (NTRS)

    1977-01-01

    The legal issues inherent in NASA's proceeding into the day-to-day operations of the space shuttle and other elements of the Space Transportation System are considered in light of the National Aeronautics and Space Act of 1958. Based on this review, it was concluded that there is no immediate need for substantive amendments to that legislation.

  13. 77 FR 7609 - Policy Letter 11-01, Performance of Inherently Governmental and Critical Functions

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-02-13

    ... ``Performance of Inherently Governmental and Critical Functions'' (76 FR 56227-56242, September 12, 2011) to... from the published Final Policy remains unchanged. The full text of the original notice is available at http://www.gpo.gov/fdsys/pkg/FR-2011-09-12/pdf/2011-23165.pdf . FOR FURTHER INFORMATION CONTACT:...

  14. Evaluation of the role of inherent Ca(2+) in phosphorus removal from wastewater system.

    PubMed

    Han, Chong; Wang, Zhen; Wu, Qianqian; Yang, Wangjin; Yang, He; Xue, Xiangxin

    2016-01-01

    The role of inherent Ca(2+) in phosphorus removal from wastewater was evaluated by batch tests. Precipitates were characterized by an X-ray diffractometer (XRD), Fourier transform infrared spectrophotometer (FT-IR) and scanning electron microscope with an energy dispersive spectrometer (EDS) system. Effects of inherent Ca(2+) on phosphorus removal through basic oxygen furnace slag (BOFS) were also analyzed. The results show that upon adjusting the pH to higher than 7.0, inherent Ca(2+) can remove phosphorus from wastewater and form Ca-P precipitates. Residual phosphorus exhibited a linear decreasing trend with increasing the pH from 7.0 to 10.0 and then remained unchanged at higher pH than 10.0. EDS determined that the precipitates contained the elements Ca, P and O. FT-IR spectra demonstrated that the functional groups of precipitates involved PO4(3-), OH(-) and CO3(2-). XRD indicated that the precipitates may consist of CaCO3 and some Ca-P phosphates such as CaHPO4, Ca4H(PO4)3, Ca3(PO4)2, and Ca5(PO4)3(OH). During the removal process of phosphorus by BOFS, due to the presence of inherent Ca(2+) in wastewater, the removal efficiency and rate of phosphorus increased by 15.5% and by a factor of about 3.0, respectively. PMID:27054736

  15. Child as Totem: Redressing the Myth of Inherent Creativity in Early Childhood

    ERIC Educational Resources Information Center

    McClure, Marissa

    2011-01-01

    In this article, I present a reexamination of the myth of inherent creativity in early childhood to elucidate how still-dominant discourses of optimization such as child development, individualism, expression, creativity, and visual realism exert limiting pressures on understandings of the art and visual culture that children consume and create.…

  16. Structural and Inherent Case in the Non-Native Processing of Spanish: Constraints on Inflectional Variability

    ERIC Educational Resources Information Center

    Hopp, Holger; León Arriaga, Mayra E.

    2016-01-01

    This article reports an eye-tracking study on the native and non-native processing of case in Spanish. Twenty-four native and 27 first language (L1) German non-native speakers of Spanish were tested on their sensitivity to case marking violations involving structural case with objects of ditransitive verbs and to violations of inherent case for…

  17. The Market for Academic Knowledge: Its Historical Emergence and Inherent Tensions

    ERIC Educational Resources Information Center

    Weik, Elke

    2014-01-01

    This paper contributes to the discussion about the marketisation of universities by providing a historical perspective. Going back to the time when the market for academic knowledge emerged, I argue that it was created through incorporating a number of inherent tensions that have been, and still are, shaping its development. I show how these…

  18. Location estimation of approaching objects is modulated by the observer's inherent and momentary action capabilities.

    PubMed

    Kandula, Manasa; Hofman, Dennis; Dijkerman, H Chris

    2016-08-01

    Action capability may be one of the factors that can influence our percept of the world. A distinction can be made between momentary action capability (action capability at that particular moment) and inherent action capability (representing a stable action capability). In the current study, we investigated whether there was a biasing effect of these two forms of action capability on visual perception of location. In a virtual reality room, subjects had to stop a moving ball from hitting a pillar. On some trials, the ball disappeared automatically during its motion. Subjects had to estimate the location of the ball's disappearance in these trials. We expected that if action is necessary but action capability (inherent or momentary) is limiting performance, the location of approaching objects with respect to the observer is underestimated. By judging the objects to be nearer than they really are, the need to select and execute the appropriate action increases, thereby facilitating quick action (Cole et al. in Psychol Sci 24(1):34-40, 2013. doi: 10.1177/0956797612446953 ). As a manipulation of inherent action capability in a virtual environment, two groups of participants (video game players vs. non-video game players) were entered into the study (high and low action capability). Momentary action capability was manipulated by using two difficulty levels in the experiment (Easy vs. Difficult). Results indicated that inherent and momentary action capabilities interacted together to influence online location judgments: Non-players underestimated locations when the task was Difficult. Taken together, our data suggest that both inherent and momentary action capabilities influence location judgments. PMID:27117302

  19. Inherent structures for soft long-range interactions in two-dimensional many-particle systems

    NASA Astrophysics Data System (ADS)

    Batten, Robert D.; Stillinger, Frank H.; Torquato, Salvatore

    2011-08-01

    We generate inherent structures, local potential-energy minima, of the "k-space overlap potential" in two-dimensional many-particle systems using a cooling and quenching simulation technique. The ground states associated with the k-space overlap potential are stealthy (i.e., completely suppress single scattering of radiation for a range of wavelengths) and hyperuniform (i.e., infinite wavelength density fluctuations vanish). However, we show via quantitative metrics that the inherent structures exhibit a range of stealthiness and hyperuniformity depending on the fraction of degrees of freedom χ that are constrained. Inherent structures in two dimensions typically contain five-particle rings, wavy grain boundaries, and vacancy-interstitial defects. The structural and thermodynamic properties of the inherent structures are relatively insensitive to the temperature from which they are sampled, signifying that the energy landscape is relatively flat along the directions sampled, with wide shallow local minima and devoid of deep wells. Using the nudged-elastic-band algorithm, we construct paths from ground-state configurations to inherent structures and identify the transition points between them. In addition, we use point patterns generated from a random sequential addition (RSA) of hard disks, which are nearly stealthy, and examine the particle rearrangements necessary to make the configurations absolutely stealthy. We introduce a configurational proximity metric to show that only small local, but collective, particle rearrangements are needed to drive initial RSA configurations to stealthy disordered ground states. These results lead to a more complete understanding of the unusual behaviors exhibited by the family of "collective-coordinate" potentials to which the k-space overlap potential belongs.

  20. Inherent structures for soft long-range interactions in two-dimensional many-particle systems.

    PubMed

    Batten, Robert D; Stillinger, Frank H; Torquato, Salvatore

    2011-08-01

    We generate inherent structures, local potential-energy minima, of the "k-space overlap potential" in two-dimensional many-particle systems using a cooling and quenching simulation technique. The ground states associated with the k-space overlap potential are stealthy (i.e., completely suppress single scattering of radiation for a range of wavelengths) and hyperuniform (i.e., infinite wavelength density fluctuations vanish). However, we show via quantitative metrics that the inherent structures exhibit a range of stealthiness and hyperuniformity depending on the fraction of degrees of freedom χ that are constrained. Inherent structures in two dimensions typically contain five-particle rings, wavy grain boundaries, and vacancy-interstitial defects. The structural and thermodynamic properties of the inherent structures are relatively insensitive to the temperature from which they are sampled, signifying that the energy landscape is relatively flat along the directions sampled, with wide shallow local minima and devoid of deep wells. Using the nudged-elastic-band algorithm, we construct paths from ground-state configurations to inherent structures and identify the transition points between them. In addition, we use point patterns generated from a random sequential addition (RSA) of hard disks, which are nearly stealthy, and examine the particle rearrangements necessary to make the configurations absolutely stealthy. We introduce a configurational proximity metric to show that only small local, but collective, particle rearrangements are needed to drive initial RSA configurations to stealthy disordered ground states. These results lead to a more complete understanding of the unusual behaviors exhibited by the family of "collective-coordinate" potentials to which the k-space overlap potential belongs. PMID:21823687

  1. Aerospace safety advisory panel

    NASA Technical Reports Server (NTRS)

    1995-01-01

    The Aerospace Safety Advisory Panel (ASAP) monitored NASA's activities and provided feedback to the NASA Administrator, other NASA officials and Congress throughout the year. Particular attention was paid to the Space Shuttle, its launch processing and planned and potential safety improvements. The Panel monitored Space Shuttle processing at the Kennedy Space Center (KSC) and will continue to follow it as personnel reductions are implemented. There is particular concern that upgrades in hardware, software, and operations with the potential for significant risk reduction not be overlooked due to the extraordinary budget pressures facing the agency. The authorization of all of the Space Shuttle Main Engine (SSME) Block II components portends future Space Shuttle operations at lower risk levels and with greater margins for handling unplanned ascent events. Throughout the year, the Panel attempted to monitor the safety activities related to the Russian involvement in both space and aeronautics programs. This proved difficult as the working relationships between NASA and the Russians were still being defined as the year unfolded. NASA's concern for the unique safety problems inherent in a multi-national endeavor appears appropriate. Actions are underway or contemplated which should be capable of identifying and rectifying problem areas. The balance of this report presents 'Findings and Recommendations' (Section 2), 'Information in Support of Findings and Recommendations' (Section 3) and Appendices describing Panel membership, the NASA response to the March 1994 ASAP report, and a chronology of the panel's activities during the reporting period (Section 4).

  2. Laboratory safety handbook

    USGS Publications Warehouse

    Skinner, E.L.; Watterson, C.A.; Chemerys, J.C.

    1983-01-01

    Safety, defined as 'freedom from danger, risk, or injury,' is difficult to achieve in a laboratory environment. Inherent dangers, associated with water analysis and research laboratories where hazardous samples, materials, and equipment are used, must be minimized to protect workers, buildings, and equipment. Managers, supervisors, analysts, and laboratory support personnel each have specific responsibilities to reduce hazards by maintaining a safe work environment. General rules of conduct and safety practices that involve personal protection, laboratory practices, chemical handling, compressed gases handling, use of equipment, and overall security must be practiced by everyone at all levels. Routine and extensive inspections of all laboratories must be made regularly by qualified people. Personnel should be trained thoroughly and repetitively. Special hazards that may involve exposure to carcinogens, cryogenics, or radiation must be given special attention, and specific rules and operational procedures must be established to deal with them. Safety data, reference materials, and texts must be kept available if prudent safety is to be practiced and accidents prevented or minimized.

  3. Module Safety Issues (Presentation)

    SciTech Connect

    Wohlgemuth, J.

    2012-02-01

    Description of how to make PV modules so that they are less likely to turn into safety hazards. Making modules inherently safer with minimum additional cost is the preferred approach for PV. Safety starts with module design to ensure redundancy within the electrical circuitry to minimize open circuits and proper mounting instructions to prevent installation related ground faults. Module manufacturers must control the raw materials and processes to ensure that that every module is built like those qualified through the safety tests. This is the reason behind the QA task force effort to develop a 'Guideline for PV Module Manufacturing QA'. Periodic accelerated stress testing of production products is critical to validate the safety of the product. Combining safer PV modules with better systems designs is the ultimate goal. This should be especially true for PV arrays on buildings. Use of lower voltage dc circuits - AC modules, DC-DC converters. Use of arc detectors and interrupters to detect arcs and open the circuits to extinguish the arcs.

  4. Environmental and safety issues of the fusion fuel cycle

    SciTech Connect

    Crocker, J.G.

    1980-01-01

    This paper discusses the environmental and safety concerns inherent in the development of fusion energy, and the current Department of Energy programs seeking to: (1) develop safe and reliable techniques for tritium control; (2) reduce the quantity of activation products produced; and (3) provide designs to limit the potential for accidents that could result in release of radioactive materials. Because of the inherent safety features of fusion and the early start that has been made in safety problem recognition and solution, fusion should be among the lower risk technologies for generation of commercial power.

  5. A literature review of safety culture.

    SciTech Connect

    Cole, Kerstan Suzanne; Stevens-Adams, Susan Marie; Wenner, Caren A.

    2013-03-01

    Workplace safety has been historically neglected by organizations in order to enhance profitability. Over the past 30 years, safety concerns and attention to safety have increased due to a series of disastrous events occurring across many different industries (e.g., Chernobyl, Upper Big-Branch Mine, Davis-Besse etc.). Many organizations have focused on promoting a healthy safety culture as a way to understand past incidents, and to prevent future disasters. There is an extensive academic literature devoted to safety culture, and the Department of Energy has also published a significant number of documents related to safety culture. The purpose of the current endeavor was to conduct a review of the safety culture literature in order to understand definitions, methodologies, models, and successful interventions for improving safety culture. After reviewing the literature, we observed four emerging themes. First, it was apparent that although safety culture is a valuable construct, it has some inherent weaknesses. For example, there is no common definition of safety culture and no standard way for assessing the construct. Second, it is apparent that researchers know how to measure particular components of safety culture, with specific focus on individual and organizational factors. Such existing methodologies can be leveraged for future assessments. Third, based on the published literature, the relationship between safety culture and performance is tenuous at best. There are few empirical studies that examine the relationship between safety culture and safety performance metrics. Further, most of these studies do not include a description of the implementation of interventions to improve safety culture, or do not measure the effect of these interventions on safety culture or performance. Fourth, safety culture is best viewed as a dynamic, multi-faceted overall system composed of individual, engineered and organizational models. By addressing all three components of

  6. High gain Raman amplifier with inherent gain flattening and dispersion compensation

    NASA Astrophysics Data System (ADS)

    Kakkar, Charu; Thyagarajan, K.

    2005-06-01

    We report here an inherently gain-flattened, high-gain discrete Raman fiber amplifier design with 21 dB net gain (±1.4 dB gain ripple) over 25 nm bandwidth. The amplifier design is based on a W-shape highly nonlinear fiber, in which, optimized spectral variation of leakage loss has been used to achieve inherent gain flattening of Raman gain. The proposed fiber has an additional advantage of having a high negative dispersion coefficient (∼-84 ps/km nm) over the operating range of wavelength and thus the designed discrete amplifier module, based on this fiber, is also capable of compensating dispersion accumulated in one span (70 km) of transmission through G.652 fiber. Hence, the designed module is proposed as a composite amplifier and dispersion-compensating unit for 25 nm bandwidth, which is capable of handling both attenuation and dispersion of one span of G. 652 transmission.

  7. Photoconduction efficiencies of metal oxide semiconductor nanowires: The material's inherent properties

    NASA Astrophysics Data System (ADS)

    Chen, R. S.; Wang, W. C.; Chan, C. H.; Lu, M. L.; Chen, Y. F.; Lin, H. C.; Chen, K. H.; Chen, L. C.

    2013-11-01

    The photoconduction (PC) efficiencies of various single-crystalline metal oxide semiconductor nanowires (NWs) have been investigated and compared based on the materials' inherent properties. The defined PC efficiency (normalized gain) of SnO2 NWs is over one to five orders of magnitude higher than that of its highly efficient counterparts such as ZnO, TiO2, WO3, and GaN. The inherent property of the material allowed the photoconductive gain of an SnO2 single-NW photodetector to easily reach 8 × 108 at a low bias of 3.0 V and a low light intensity of 0.05 Wm-2, which is the optimal reported value so far for the single-NW photodetectors. The probable physical origins, such as charged surface state density and surface band bending, that caused the differences in PC efficiencies and carrier lifetimes are also discussed.

  8. Interference of solar-probe inherent atmosphere with in-situ observations

    SciTech Connect

    Hassanein, A.; Alekseev, V.A.; Konkashbaev, A.I.; Konkashbaev, I.K.; Nikandrov, L.B.

    1998-01-01

    The solar corona is the source of solar wind that leads to the existence of the heliosphere and plays a crucial role in solar terrestrial phenomena. A comprehensive understanding of these phenomena can be provided only by directly measuring ion and electron velocity distributions, plasma waves, and fluxes of energetic particles. The problem presented by the inherent atmosphere of a spacecraft moving in the vicinity of the sun (4--20)R{sub {circle_dot}} and its influence on in-situ measurements of the solar corona plasma is the key to the realization and success of any solar probe mission. Models are developed to study and evaluate the effect of the inherent atmosphere on the in-situ measurements of future solar probes.

  9. Inherent tone of human bronchus: role of eicosanoids and the epithelium

    PubMed Central

    Watson, N; Magnussen, H; Rabe, K F

    1997-01-01

    Airway preparations of different species possess varying degrees of inherent tone which is the result of different metabolites of arachidonic acid in different species. In human bronchial smooth muscle in vitro we have investigated the effects of 5-lipoxygenase inhibition (zileuton, 10 μM), cyclo-oxygenase inhibition (indomethacin, 1 μM) and mechanical epithelium removal on inherent tone. The shunting of arachidonic acid by inhibition of one or other of these enzymes, as a possible explanation for the effects observed, has also been investigated. Zileuton caused a significant fall in tone either alone (−107±33 mg) or after cyclo-oxygenase inhibition (−203±48 mg) and this effect was not significantly altered by epithelial removal (−191±43 mg alone; −333±88 mg after indomethacin). Indomethacin increased tone when applied alone (160±94 mg), but this effect only reached statistical significance after 5-lipoxygenase inhibition, (210±81 mg; P<0.05). Epithelial removal did not alter the effect of indomethacin when applied alone (213±97 mg), but significantly reduced the effect of indomethacin after 5-lipoxygenase inhibition (34±23 mg; P<0.05). These data suggest that inherent tone in human bronchus is largely the result of contractile 5-lipoxygenase products. However, the involvement of cyclo-oxygenase products cannot entirely be discounted, since in the presence of 5-lipoxygenase inhibition contractile and relaxant eicosanoids originating from the bronchial epithelium appear to influence significantly inherent tone. PMID:9249244

  10. The psychology of inherence is self-referential (and that is a good thing).

    PubMed

    Bookstein, Fred L

    2014-10-01

    Cimpian & Salomon (C&S) appear to characterize the inherence heuristic and essentialism as unwise or childish aspects of human reasoning. But actually, these cognitive modes lie at the core of statistical analysis across all of the quantitative sciences, including the developmental cognitive psychology in which the argument here is couched. Their whole argument is as much an example of its topic as an analysis of it. PMID:25388030

  11. Brain activation patterns at exhaustion in rats that differ in inherent exercise capacity.

    PubMed

    Foley, Teresa E; Brooks, Leah R; Gilligan, Lori J; Burghardt, Paul R; Koch, Lauren G; Britton, Steven L; Fleshner, Monika

    2012-01-01

    In order to further understand the genetic basis for variation in inherent (untrained) exercise capacity, we examined the brains of 32 male rats selectively bred for high or low running capacity (HCR and LCR, respectively). The aim was to characterize the activation patterns of brain regions potentially involved in differences in inherent running capacity between HCR and LCR. Using quantitative in situ hybridization techniques, we measured messenger ribonuclease (mRNA) levels of c-Fos, a marker of neuronal activation, in the brains of HCR and LCR rats after a single bout of acute treadmill running (7.5-15 minutes, 15° slope, 10 m/min) or after treadmill running to exhaustion (15-51 minutes, 15° slope, initial velocity 10 m/min). During verification of trait differences, HCR rats ran six times farther and three times longer prior to exhaustion than LCR rats. Running to exhaustion significantly increased c-Fos mRNA activation of several brain areas in HCR, but LCR failed to show significant elevations of c-Fos mRNA at exhaustion in the majority of areas examined compared to acutely run controls. Results from these studies suggest that there are differences in central c-Fos mRNA expression, and potential brain activation patterns, between HCR and LCR rats during treadmill running to exhaustion and these differences could be involved in the variation in inherent running capacity between lines. PMID:23028992

  12. Liver-inherent immune system: its role in blood-stage malaria

    PubMed Central

    Wunderlich, Frank; Al-Quraishy, Saleh; Dkhil, Mohamed A.

    2014-01-01

    The liver is well known as that organ which is obligately required for the intrahepatocyte development of the pre-erythrocytic stages of the malaria-causative agent Plasmodium. However, largely neglected is the fact that the liver is also a central player of the host defense against the morbidity- and mortality-causing blood stages of the malaria parasites. Indeed, the liver is equipped with a unique immune system that acts locally, however, with systemic impact. Its main “antipodal” functions are to recognize and to generate effective immunoreactivity against pathogens on the one hand, and to generate tolerance to avoid immunoreactivity with “self” and harmless substances as dietary compounds on the other hand. This review provides an introductory survey of the liver-inherent immune system: its pathogen recognition receptors including Toll-like receptors (TLRs) and its major cell constituents with their different facilities to fight and eliminate pathogens. Then, evidence is presented that the liver is also an essential organ to overcome blood-stage malaria. Finally, we discuss effector responses of the liver-inherent immune system directed against blood-stage malaria: activation of TLRs, acute phase response, phagocytic activity, cytokine-mediated pro- and anti-inflammatory responses, generation of “protective” autoimmunity by extrathymic T cells and B-1 cells, and T cell-mediated repair of liver injuries mainly produced by malaria-induced overreactions of the liver-inherent immune system. PMID:25408684

  13. [Study on using apparent spectrum to retrieve the inherent optical properties of ocean water].

    PubMed

    Zhang, Min-wei; Dong, Qing; Tang, Jun-wu; Song, Qing-jun

    2011-05-01

    The inherent optical properties are needed when establishing the semi-analytic model in the ocean color retrieval algorithm. Using the in-situ measurements, a retrieval model for inherent optical properties from remote sensing reflectance was established. The in-situ data measured in the 2003 spring cruise over the Yellow and East China Seas is introduced. The measurement method for remote sensing reflectance, particle backscattering and absorption coefficients are detailed. Based on the bio-optical model, the inherent optical properties were retrieved by optimization of Nelder-Mead simplex. The retrieval results of the absorption and backscattering coefficients for the material other than pure water were compared with the counterpart of the in-situ measurements. The comparison shows that the root-mean-square relative error for the absorption coefficient of materials other than water is less than 33%. The value is 30% for the particle backscattering coefficient. The analysis of the error shows that the retrieval model established in this paper can provide an efficient approach to retrieving the absorption and backscattering coefficients. The retrieval model can provide a reference for the application of remotely sensed data to the research on the bio-optical properties of Yellow and East China Seas. PMID:21800610

  14. Inherent directionality explains the lack of feedback loops in empirical networks

    PubMed Central

    Domínguez-García, Virginia; Pigolotti, Simone; Muñoz, Miguel A.

    2014-01-01

    We explore the hypothesis that the relative abundance of feedback loops in many empirical complex networks is severely reduced owing to the presence of an inherent global directionality. Aimed at quantifying this idea, we propose a simple probabilistic model in which a free parameter γ controls the degree of inherent directionality. Upon strengthening such directionality, the model predicts a drastic reduction in the fraction of loops which are also feedback loops. To test this prediction, we extensively enumerated loops and feedback loops in many empirical biological, ecological and socio-technological directed networks. We show that, in almost all cases, empirical networks have a much smaller fraction of feedback loops than network randomizations. Quite remarkably, this empirical finding is quantitatively reproduced, for all loop lengths, by our model by fitting its only parameter γ. Moreover, the fitted value of γ correlates quite well with another direct measurement of network directionality, performed by means of a novel algorithm. We conclude that the existence of an inherent network directionality provides a parsimonious quantitative explanation for the observed lack of feedback loops in empirical networks. PMID:25531727

  15. Inherent directionality explains the lack of feedback loops in empirical networks.

    PubMed

    Domínguez-García, Virginia; Pigolotti, Simone; Muñoz, Miguel A

    2014-01-01

    We explore the hypothesis that the relative abundance of feedback loops in many empirical complex networks is severely reduced owing to the presence of an inherent global directionality. Aimed at quantifying this idea, we propose a simple probabilistic model in which a free parameter γ controls the degree of inherent directionality. Upon strengthening such directionality, the model predicts a drastic reduction in the fraction of loops which are also feedback loops. To test this prediction, we extensively enumerated loops and feedback loops in many empirical biological, ecological and socio-technological directed networks. We show that, in almost all cases, empirical networks have a much smaller fraction of feedback loops than network randomizations. Quite remarkably, this empirical finding is quantitatively reproduced, for all loop lengths, by our model by fitting its only parameter γ. Moreover, the fitted value of γ correlates quite well with another direct measurement of network directionality, performed by means of a novel algorithm. We conclude that the existence of an inherent network directionality provides a parsimonious quantitative explanation for the observed lack of feedback loops in empirical networks. PMID:25531727

  16. Kinetic modeling of inherent mineral catalyzed NO reduction by biomass char.

    PubMed

    Wu, X Y; Song, Q; Zhao, H B; Zhang, Z H; Yao, Q

    2014-04-01

    The evolution of rice straw char reactivity during reaction with NO was examined in differential reactor at 900 and 1000 °C. Original and acid-washed rice straw chars were used. Surface area and mineral content of char samples with different conversion were analyzed. The reactivity of the acid-washed char increased until conversion Xchar = 20%, remained constant, and then decreased continuously to zero. The reactivity of the original char decreased continuously to zero throughout the reaction, with a faster decrease at 1000 °C. Mineral transformation during original char reaction was obvious. Concentration of acid-soluble K decreased about 56% and 90% at 900 and 1000 °C. Ca and Mg released little to gas phase, but reacted with SiO2 in a small amount. The evolution of the acid-washed char reactivity correlated well with the development of surface area and was well predicted by random pore model. The reactivity of the original char depended not only on the development of surface area, but also on transformation of inherent minerals, mainly K. A two-reaction model was built which well predicted inherent K transformation. A modified random pore model was developed, which successfully simulated inherent mineral catalyzed char-NO reaction. PMID:24588459

  17. Influence of solar-probe inherent atmosphere on in-situ observations

    SciTech Connect

    Hassanein, A.; Konkashbaev, A.I.; Konkashbaev, I.K.; Nikandrov, L.B.

    1998-08-01

    The solar corona is the source of the solar wind, which is responsible for the heliosphere and plays a crucial role in solar/terrestrial phenomena. A comprehensive understanding of these phenomena can be established only by directly measuring ion and electron velocity distributions, plasma waves, and fluxes of energetic particles near the sun. The problem resulting from the inherent atmosphere of a spacecraft moving in the vicinity of the sun and the influence of this atmosphere on in-situ measurements of the solar corona plasma is key to the realization and success of any solar probe mission. To evaluate the influence of the probe-inherent atmosphere on in-situ observations, the authors have developed comprehensive radiation hydrodynamic models. The physics of plasma/probe/vapor interaction are also being developed in a self-consistent model to predict the effect of probe inherent atmosphere on in-situ measurements of corona parameters during solar flares. Interaction of the ionized atmosphere with the ambient natural plasma will create a turbulent shock wave that can affect in-situ measurements and must be taken into account in designing the spacecraft and its scientific components.

  18. Disease resistance is related to inherent swimming performance in Atlantic salmon

    PubMed Central

    2013-01-01

    Background Like humans, fish can be classified according to their athletic performance. Sustained exercise training of fish can improve growth and physical capacity, and recent results have documented improved disease resistance in exercised Atlantic salmon. In this study we investigated the effects of inherent swimming performance and exercise training on disease resistance in Atlantic salmon. Atlantic salmon were first classified as either poor or good according to their swimming performance in a screening test and then exercise trained for 10 weeks using one of two constant-velocity or two interval-velocity training regimes for comparison against control trained fish (low speed continuously). Disease resistance was assessed by a viral disease challenge test (infectious pancreatic necrosis) and gene expression analyses of the host response in selected organs. Results An inherently good swimming performance was associated with improved disease resistance, as good swimmers showed significantly better survival compared to poor swimmers in the viral challenge test. Differences in mortalities between poor and good swimmers were correlated with cardiac mRNA expression of virus responsive genes reflecting the infection status. Although not significant, fish trained at constant-velocity showed a trend towards higher survival than fish trained at either short or long intervals. Finally, only constant training at high intensity had a significant positive effect on fish growth compared to control trained fish. Conclusions This is the first evidence suggesting that inherent swimming performance is associated with disease resistance in fish. PMID:23336751

  19. Liver-inherent immune system: its role in blood-stage malaria.

    PubMed

    Wunderlich, Frank; Al-Quraishy, Saleh; Dkhil, Mohamed A

    2014-01-01

    The liver is well known as that organ which is obligately required for the intrahepatocyte development of the pre-erythrocytic stages of the malaria-causative agent Plasmodium. However, largely neglected is the fact that the liver is also a central player of the host defense against the morbidity- and mortality-causing blood stages of the malaria parasites. Indeed, the liver is equipped with a unique immune system that acts locally, however, with systemic impact. Its main "antipodal" functions are to recognize and to generate effective immunoreactivity against pathogens on the one hand, and to generate tolerance to avoid immunoreactivity with "self" and harmless substances as dietary compounds on the other hand. This review provides an introductory survey of the liver-inherent immune system: its pathogen recognition receptors including Toll-like receptors (TLRs) and its major cell constituents with their different facilities to fight and eliminate pathogens. Then, evidence is presented that the liver is also an essential organ to overcome blood-stage malaria. Finally, we discuss effector responses of the liver-inherent immune system directed against blood-stage malaria: activation of TLRs, acute phase response, phagocytic activity, cytokine-mediated pro- and anti-inflammatory responses, generation of "protective" autoimmunity by extrathymic T cells and B-1 cells, and T cell-mediated repair of liver injuries mainly produced by malaria-induced overreactions of the liver-inherent immune system. PMID:25408684

  20. Vaccine Safety

    MedlinePlus

    ... During Pregnancy Frequently Asked Questions about Vaccine Recalls Historical Vaccine Safety Concerns FAQs about GBS and Menactra ... CISA Resources for Healthcare Professionals Evaluation Current Studies Historical Background 2001-12 Publications Technical Reports Vaccine Safety ...

  1. Safety Handbook.

    ERIC Educational Resources Information Center

    Montgomery County Public Schools, Rockville, MD.

    Safety policies, procedures, and related information are presented in this manual to assist school personnel in a continuing program of accident prevention. Chapter 1 discusses safety education and accident prevention in general. Chapter 2 covers traffic regulations relating to school safety patrols, school bus transportation, bicycles, and…

  2. Product Engineering Class in the Software Safety Risk Taxonomy for Building Safety-Critical Systems

    NASA Technical Reports Server (NTRS)

    Hill, Janice; Victor, Daniel

    2008-01-01

    When software safety requirements are imposed on legacy safety-critical systems, retrospective safety cases need to be formulated as part of recertifying the systems for further use and risks must be documented and managed to give confidence for reusing the systems. The SEJ Software Development Risk Taxonomy [4] focuses on general software development issues. It does not, however, cover all the safety risks. The Software Safety Risk Taxonomy [8] was developed which provides a construct for eliciting and categorizing software safety risks in a straightforward manner. In this paper, we present extended work on the taxonomy for safety that incorporates the additional issues inherent in the development and maintenance of safety-critical systems with software. An instrument called a Software Safety Risk Taxonomy Based Questionnaire (TBQ) is generated containing questions addressing each safety attribute in the Software Safety Risk Taxonomy. Software safety risks are surfaced using the new TBQ and then analyzed. In this paper we give the definitions for the specialized Product Engineering Class within the Software Safety Risk Taxonomy. At the end of the paper, we present the tool known as the 'Legacy Systems Risk Database Tool' that is used to collect and analyze the data required to show traceability to a particular safety standard

  3. Experimentally determined stiffness and damping of an inherently compensated air squeeze-film damper

    NASA Technical Reports Server (NTRS)

    Cunningham, R. E.

    1975-01-01

    Values of damping and stiffness were determined experimentally for an externally pressurized, inherently compensated, compressible squeeze-film damper up to excitation frequencies of 36,000 cycles per minute. Experimental damping values were higher than theory predicted at low squeeze numbers and less than predicted at high squeeze numbers. Experimental values of air film stiffness were less than theory predicted at low squeeze numbers and much greater at higher squeeze numbers. Results also indicate sufficient damping to attenuate amplitudes and forces at the critical speed when using three dampers in the flexible support system of a small, lightweight turborotor.

  4. On the Inherent Self-Excited Macroscopic Randomness of Chaotic Three-Body Systems

    NASA Astrophysics Data System (ADS)

    Liao, Shijun; Li, Xiaoming

    What is the origin of macroscopic randomness (uncertainty)? This is one of the most fundamental open questions for human beings. In this paper, 10 000 samples of reliable (convergent), multiple-scale (from 10-60 to 102) numerical simulations of a chaotic three-body system indicate that, without any external disturbance, the microscopic inherent uncertainty (in the level of 10-60) due to physical fluctuation of initial positions of the three-body system enlarges exponentially into macroscopic randomness (at the level O(1)) until t = T*, the so-called physical limit time of prediction, but propagates algebraically thereafter when accurate prediction of orbit is impossible. Note that these 10 000 samples use micro-level, inherent physical fluctuations of initial position, which have nothing to do with human beings. Especially, the differences of these 10 000 fluctuations are mathematically so small (in the level of 10-60) that they are physically the same since a distance shorter than a Planck length does not make physical sense according to the string theory. This indicates that the macroscopic randomness of the chaotic three-body system is self-excited, say, without any external force or disturbances, from the inherent micro-level uncertainty. It provides us the new concept "self-excited macroscopic randomness (uncertainty)". The macroscopic randomness is found to be dependent upon microscopic uncertainty, from the statistical viewpoint. In addition, it is found that, without any external disturbance, the chaotic three-body system might randomly disrupt with symmetry-breaking at t = 1000 in about 25% probability, which provides us new concepts "self-excited random disruption", "self-excited random escape" and "self-excited symmetry breaking" of the chaotic three-body system. Hence, it suggests that a chaotic three-body system might randomly evolve by itself, without any external forces or disturbance. Thus, the world is essentially uncertain, since such kind of self

  5. Deliberate practice theory: relevance, effort, and inherent enjoyment of music practice.

    PubMed

    Hyllegard, Randy; Bories, Tamara L

    2008-10-01

    This study examined three assumptions of the theory of deliberate practice for practice playing music on an electronic keyboard. 40 undergraduate students, divided into two separate groups, practiced one of two music sequences and rated the relevance of practice for improving performance on the sequences, the amount of effort needed to learn the sequences, and the inherent enjoyment of practice sessions. Findings for each assumption were consistent with those suggested by theory but also showed that perceptions are affected by the amount of practice completed and performance of the skill. PMID:19093605

  6. Inherent relation between visibility and resolution in thermal light ghost imaging

    NASA Astrophysics Data System (ADS)

    Song, Xin-Bing; Zhang, Su-Heng; Cao, Dezhong; Xiong, Jun; Wang, Haibo; Wang, Kaige

    2016-04-01

    Ghost imaging with thermal light inevitably has a noise background, which greatly decreases the visibility of the reconstructed image. In this paper we formulate a fundamental equation that the integration of the distribution of any ghost image equals a constant in relation to the coherence of the thermal light source. With this equation we strictly demonstrate that the average visibility of ghost imaging is inversely proportional to its image resolution. In the same time, this inherently inverse relation is verified by our numerical simulation and experimental results.

  7. The near boiling reactor: Conceptual design of a small inherently safe nuclear reactor to extend the operational capability of the Victoria Class submarine

    NASA Astrophysics Data System (ADS)

    Cole, Christopher J. P.

    Nuclear power has several unique advantages over other air independent energy sources for nuclear combat submarines. An inherently safe, small nuclear reactor, capable of supply the hotel load of the Victoria Class submarines, has been conceptually developed. The reactor is designed to complement the existing diesel electric power generation plant presently onboard the submarine. The reactor, rated at greater than 1 MW thermal, will supply electricity to the submarine's batteries through an organic Rankine cycle energy conversion plant at 200 kW. This load will increase the operational envelope of the submarine by providing up to 28 continuous days submerged, allowing for an enhanced indiscretion ratio (ratio of time spent on the surface versus time submerged) and a limited under ice capability. The power plant can be fitted into the existing submarine by inserting a 6 m hull plug. With its simplistic design and inherent safety features, the reactor plant will require a minimal addition to the crew. The reactor employs TRISO fuel particles for increased safety. The light water coolant remains at atmospheric pressure, exiting the core at 96°C. Burn-up control and limiting excess reactivity is achieved through movable reflector plates. Shut down and regulatory control is achieved through the thirteen hafnium control rods. Inherent safety is achieved through the negative prompt and delayed temperature coefficients, as well as the negative void coefficient. During a transient, the boiling of the moderator results in a sudden drop in reactivity, essentially shutting down the reactor. It is this characteristic after which the reactor has been named. The design of the reactor was achieved through modelling using computer codes such as MCNP5, WIMS-AECL, FEMLAB, and MicroShield5, in addition to specially written software for kinetics, heat transfer and fission product poisoning calculations. The work has covered a broad area of research and has highlighted additional areas

  8. Strain rate dependence of the tensile properties of V-(4--5%)Cr-(4--5%)Ti irradiated in EBR-II and HFBR

    SciTech Connect

    Zinkle, S.J.; Snead, L.L.; Robertson, J.P.; Rowcliffe, A.F.

    1998-03-01

    Elevated temperature tensile tests performed on V-(405)Cr-(4-5)Ti indicate that the yield stress increases with increasing strain rate for irradiation and test temperatures near 200 C, and decreases with increasing strain rate for irradiation and test temperatures near 400 C. This observation is in qualitative agreement with the temperature-dependent strain rate effects observed on unirradiated specimens, and implies that some interstitial solute remains free to migrate in irradiated specimens. Additional strain rate data at different temperatures are needed.

  9. National Safety Council

    MedlinePlus

    ... Introduction Safety Management Systems Workplace Safety Consulting Employee Perception Surveys Research Journey to Safety Excellence Join the ... Safety Safety Management Systems Workplace Safety Consulting Employee Perception Surveys Research Journey to Safety Excellence Join the ...

  10. Guideline for the preparation of a contractor safety plan

    SciTech Connect

    Stinnett, L

    1982-04-01

    This document is only a guideline for contractors to use in formalizing a safety program or preparing a safety plan. It contains a format of a suggested safety plan as well as pertinent safety elements which should be considered for inclusion. However, consideration of only those items listed may not be sufficient. Each contractor should include in the safety plan particular reference to those elements peculiar to the inherent hazards of the contractor's specific type of construction services, whether the hazard is shown in the list of safety elements or not. Each safety plan should be reviewed annually by the contractor's management. Reissue of the safety plan is mandatory if safety requirements have changed, or if the contractor's address or management (approval signature) has changed.

  11. Neural network approach to retrieve the inherent optical properties of the ocean from observations of MODIS.

    PubMed

    Ioannou, Ioannis; Gilerson, Alexander; Gross, Barry; Moshary, Fred; Ahmed, Samir

    2011-07-01

    Retrieving the inherent optical properties of water from remote sensing multispectral reflectance measurements is difficult due to both the complex nature of the forward modeling and the inherent nonlinearity of the inverse problem. In such cases, neural network (NN) techniques have a long history in inverting complex nonlinear systems. The process we adopt utilizes two NNs in parallel. The first NN is used to relate the remote sensing reflectance at available MODIS-visible wavelengths (except the 678 nm fluorescence channel) to the absorption and backscatter coefficients at 442 nm (peak of chlorophyll absorption). The second NN separates algal and nonalgal absorption components, outputting the ratio of algal-to-nonalgal absorption. The resulting synthetically trained algorithm is tested using both the NASA Bio-Optical Marine Algorithm Data Set (NOMAD), as well as our own field datasets from the Chesapeake Bay and Long Island Sound, New York. Very good agreement is obtained, with R² values of 93.75%, 90.67%, and 86.43% for the total, algal, and nonalgal absorption, respectively, for the NOMAD. For our field data, which cover absorbing waters up to about 6 m⁻¹, R² is 91.87% for the total measured absorption. PMID:21743516

  12. Are Autobiographical Memories Inherently Social? Evidence from an fMRI Study

    PubMed Central

    Wilbers, Linda; Deuker, Lorena; Fell, Juergen; Axmacher, Nikolai

    2012-01-01

    The story of our lifetime – our narrative self – is constructed from our autobiographical memories. A central claim of social psychology is that this narrative self is inherently social: When we construct our lives, we do so in a real or imagined interaction. This predicts that self-referential processes which are involved in recall of autobiographical memories overlap with processes involved in social interactions. Indeed, previous functional MRI studies indicate that regions in the medial prefrontal cortex (mPFC) are activated during autobiographical memory recall and virtual communication. However, no fMRI study has investigated recall of autobiographical memories in a real-life interaction. We developed a novel paradigm in which participants overtly reported self-related and other-related memories to an experimenter, whose non-verbal reactions were being filmed and online displayed to the participants in the scanner. We found that recall of autobiographical vs. non-autobiographical memories was associated with activation of the mPFC, as was recall in the social as compared to a non-social control condition; however, both contrasts involved different non-overlapping regions within the mPFC. These results indicate that self-referential processes involved in autobiographical memory recall are different from processes supporting social interactions, and argue against the hypothesis that autobiographical memories are inherently social. PMID:23028774

  13. Inherent noise appears as a Lévy walk in fish schools

    PubMed Central

    Murakami, Hisashi; Niizato, Takayuki; Tomaru, Takenori; Nishiyama, Yuta; Gunji, Yukio-Pegio

    2015-01-01

    Recent experimental and observational data have revealed that the internal structures of collective animal groups are not fixed in time. Rather, individuals can produce noise continuously within their group. These individuals’ movements on the inside of the group, which appear to collapse the global order and information transfer, can enable interactions with various neighbors. In this study, we show that noise generated inherently in a school of ayus (Plecoglossus altivelis) is characterized by various power-law behaviors. First, we show that individual fish move faster than Brownian walkers with respect to the center of the mass of the school as a super-diffusive behavior, as seen in starling flocks. Second, we assess neighbor shuffling by measuring the duration of pair-wise contact and find that this distribution obeys the power law. Finally, we show that an individual’s movement in the center of a mass reference frame displays a Lévy walk pattern. Our findings suggest that inherent noise (i.e., movements and changes in the relations between neighbors in a directed group) is dynamically self-organized in both time and space. In particular, Lévy walk in schools can be regarded as a well-balanced movement to facilitate dynamic collective motion and information transfer throughout the group. PMID:26039595

  14. Regularities inherent to Solar Energetic Particle events and fluxes which define properties of interplanetary radiation field

    NASA Astrophysics Data System (ADS)

    Nymmik, Rikho

    High-energy radiation in the interplanetary space is mainly due to background particles of galactic cosmic rays (GCR) and solar high-energy particles (SEP), the appearance of which has probabilistic nature. If the basic regularities inherent to galactic cosmic rays are relatively well known, the regularities inherent to SEP events are sometimes inaccurate or even erroneous. Ambiguous estimations of the SEP fluxes may lead to incorrect estimates of radiation hazards in the interplanetary space and to significant errors in planning of future human activities in space. Erroneous views on SEP fluxes in space lead to inaccurate conclusions about the characteristics of the radiation environment such as: • Probability and frequency of occurrence of SEP events in the interplanetary space; • SEP events distribution by magnitude and probable values of maximum fluxes; • Shape of the energy spectra of the solar energetic particles. Wrong understanding of SEP features makes difficult the objective assessment of dose characteristics and linear energy transfer for the protection of spacecraft constructions, spacecrafts crew, and future human bases on Moon and Mars.

  15. Inherent noise appears as a Lévy walk in fish schools.

    PubMed

    Murakami, Hisashi; Niizato, Takayuki; Tomaru, Takenori; Nishiyama, Yuta; Gunji, Yukio-Pegio

    2015-01-01

    Recent experimental and observational data have revealed that the internal structures of collective animal groups are not fixed in time. Rather, individuals can produce noise continuously within their group. These individuals' movements on the inside of the group, which appear to collapse the global order and information transfer, can enable interactions with various neighbors. In this study, we show that noise generated inherently in a school of ayus (Plecoglossus altivelis) is characterized by various power-law behaviors. First, we show that individual fish move faster than Brownian walkers with respect to the center of the mass of the school as a super-diffusive behavior, as seen in starling flocks. Second, we assess neighbor shuffling by measuring the duration of pair-wise contact and find that this distribution obeys the power law. Finally, we show that an individual's movement in the center of a mass reference frame displays a Lévy walk pattern. Our findings suggest that inherent noise (i.e., movements and changes in the relations between neighbors in a directed group) is dynamically self-organized in both time and space. In particular, Lévy walk in schools can be regarded as a well-balanced movement to facilitate dynamic collective motion and information transfer throughout the group. PMID:26039595

  16. Inherent instability by antibonding coupling in AgSbTe2

    NASA Astrophysics Data System (ADS)

    Shinya, Hikari; Masago, Akira; Fukushima, Tetsuya; Katayama-Yoshida, Hiroshi

    2016-04-01

    In the present paper, an inherent instability in the ternary chalcogenide compound AgSbTe2 is described from the electronic structure viewpoint. Our calculations, which are based on the cluster expansion method, suggest nine stable crystal structures involving the most stable structure with Fd\\bar{3}m symmetry. The effective pair interactions calculated by the generalized perturbation method point out that the stability of these structures originates from the number of linear arrangements of the Ag-Te-Sb atomic bonds. Moreover, it is found that AgSbTe2 has a special electronic structure, where the dominant components of the top of the valence band are the Te-5p antibonding states. Such an antibonding contribution leads to an inherent instability, such that the system spontaneously forms various mutation phases caused by charge-compensated defect complexes. We propose that these mutation phases play an important role in the thermal conductivity and thermoelectric efficiency in AgSbTe2.

  17. Cellular heterogeneity mediates inherent sensitivity-specificity tradeoff in cancer targeting by synthetic circuits.

    PubMed

    Morel, Mathieu; Shtrahman, Roman; Rotter, Varda; Nissim, Lior; Bar-Ziv, Roy H

    2016-07-19

    Synthetic gene circuits are emerging as a versatile means to target cancer with enhanced specificity by combinatorial integration of multiple expression markers. Such circuits must also be tuned to be highly sensitive because escape of even a few cells might be detrimental. However, the error rates of decision-making circuits in light of cellular variability in gene expression have so far remained unexplored. Here, we measure the single-cell response function of a tunable logic AND gate acting on two promoters in heterogeneous cell populations. Our analysis reveals an inherent tradeoff between specificity and sensitivity that is controlled by the AND gate amplification gain and activation threshold. We implement a tumor-mimicking cell-culture model of cancer cells emerging in a background of normal ones, and show that molecular parameters of the synthetic circuits control specificity and sensitivity in a killing assay. This suggests that, beyond the inherent tradeoff, synthetic circuits operating in a heterogeneous environment could be optimized to efficiently target malignant state with minimal loss of specificity. PMID:27385823

  18. Effects of inherent envelope fluctuations in forward maskers for listeners with normal and impaired hearinga)

    PubMed Central

    Svec, Adam; Dubno, Judy R.; Nelson, Peggy B.

    2015-01-01

    Gaussian noise simultaneous maskers yield higher masked thresholds for pure tones than low-fluctuation noise simultaneous maskers for listeners with normal hearing. This increased masking effectiveness is thought to be due to inherent fluctuations in the temporal envelope of Gaussian noise, but effects of fluctuating forward maskers are unknown. Because differences in forward masking due to age and hearing loss are known, the current study assessed effects of masker envelope fluctuations for forward maskers in younger and older adults with normal hearing and older adults with hearing loss. Detection thresholds were measured in these three participant groups for a pure-tone probe in quiet and in Gaussian and low-fluctuation noise forward maskers with either 1 or 1/3 equivalent rectangular bandwidths. Higher masked thresholds were obtained for forward maskers with greater inherent envelope fluctuations for younger adults with normal hearing. This increased effectiveness of highly fluctuating forward maskers was similar for older adults with normal and impaired hearing. Because differences in recovery from forward masking between listeners with normal and impaired hearing may relate to differences in cochlear nonlinearities, these results suggest that mechanisms other than cochlear nonlinearities may be responsible for recovery from rapid masker envelope fluctuations. PMID:25786946

  19. Registration of optical imagery and LiDAR data using an inherent geometrical constraint.

    PubMed

    Zhang, Wuming; Zhao, Jing; Chen, Mei; Chen, Yiming; Yan, Kai; Li, Linyuan; Qi, Jianbo; Wang, Xiaoyan; Luo, Jinghui; Chu, Qing

    2015-03-23

    A novel method for registering imagery with Light Detection And Ranging (LiDAR) data is proposed. It is based on the phenomenon that the back-projection of LiDAR point cloud of an object should be located within the object boundary in the image. Using this inherent geometrical constraint, the registration parameters computation of both data sets only requires LiDAR point clouds of several objects and their corresponding boundaries in the image. The proposed registration method comprises of four steps: point clouds extraction, boundary extraction, back-projection computation and registration parameters computation. There are not any limitations on the geometrical and spectral properties of the object. So it is suitable not only for structured scenes with man-made objects but also for natural scenes. Moreover, the proposed method based on the inherent geometrical constraint can register two data sets derived from different parts of an object. It can be used to co-register TLS (Terrestrial Laser Scanning) LiDAR point cloud and UAV (Unmanned aerial vehicle) image, which are obtaining more attention in the forest survey application. Using initial registration parameters comparable to POS (position and orientation system) accuracy, the performed experiments validated the feasibility of the proposed registration method. PMID:25837107

  20. The motivation for biological aggression is an inherent and common aspect of the human behavioural repertoire.

    PubMed

    Rózsa, Lajos

    2009-02-01

    According to a widespread opinion shared by the vast majority of historians, instances of aggression using pathogen weapons constitute extremely rare events in human history. Similarly, students of human behaviour tend to believe that their science plays no role in explaining this phenomenon, which is held to be exceptional and abnormal. Contrary to this dominant view, I argue that Hamiltonian spite - like Hamiltonian altruism - is an inherent part of the human behavioural repertoire and it includes the use of pathogens for spiteful purposes. This paradigm is supported by the following observations. The use of pathogens as weapons emerged far before the scientific understanding of the nature of infections and epidemics, though it has been underrepresented in written history ever since. It is also present in our expectations concerning the likely behaviour of an enemy and it is also a frequent component of threats. Several languages appear to bear linguistic references to our motivation for biological aggression in profanity. Finally, given that wartime epidemics kill people at a rate comparable to (or exceeding) that of mechanical weapons, all wars fought in recorded history incorporated an element of aggression through biological means. On the basis of these arguments, I claim that the motivation for biological aggression is an inherent and common aspect of past and present human behaviour. PMID:19006651

  1. The inherent dynamics of isotropic- and nematic-phase liquid crystals

    NASA Astrophysics Data System (ADS)

    Frechette, Layne; Stratt, Richard M.

    2016-06-01

    The geodesic (shortest) pathways through the potential energy landscape of a liquid can be thought of as defining what its dynamics would be if thermal noise were removed, revealing what we have called the "inherent dynamics" of the liquid. We show how these inherent paths can be located for a model liquid crystal former, showing, in the process, how the molecular mechanisms of translation and reorientation compare in the isotropic and nematic phases of these systems. These mechanisms turn out to favor the preservation of local orientational order even under macroscopically isotropic conditions (a finding consistent with the experimental observation of pseudonematic domains in these cases), but disfavor the maintenance of macroscopic orientational order, even in the nematic phase. While the most efficient nematic pathways that maintain nematic order are indeed shorter than those that do not, it is apparently difficult for the system to locate these paths, suggesting that molecular motion in liquid-crystal formers is dynamically frustrated, and reinforcing the sense that there are strong analogies between liquid crystals and supercooled liquids.

  2. Detection of inherent and laser-induced scatter in optical materials

    SciTech Connect

    Sheehan, L.; Kozlowski, M.

    1995-07-05

    As Lawrence Livermore National Laboratory moves forward with the design of the National Ignition Facility (NIF) in the Inertial Confinement Fusion (ICF) program, issues relating to the detection and measurement of laser-induced damage on large optics must be addressed. Currently, microscopy is used to evaluate surface quality and measure damage thresholds on small witness samples. In order to evaluate large areas, an automated system was constructed which can scan optics with dimensions as large as 1 meter and weighing as much as 400 pounds. The use of microscopy as the main test diagnostic has been replaced with an optical scatter detection system. Now large areas can be rastered, and maps can be generated, reflecting inherent and laser-induced scatter in multilayer optical coatings and bulk materials. The integrated scattered light from a test piece is measured in transmission using a HeNe laser as the probe source. When the probe beam is overlapped on a pulsed, high power, ND:YAG laser beam, damage related scatter may be measured. This technique has been used for: (1) mapping of inherent scatter in an optic, (2) on-the-fly damage detection during a high fluence raster scan of an optic, and (3) single site damage evaluation for the determination of a laser damage threshold. Damage thresholds measured with the scatter diagnostic compare within measurement error to those attained using 100 {times} microscopy.

  3. The inherent dynamics of isotropic- and nematic-phase liquid crystals.

    PubMed

    Frechette, Layne; Stratt, Richard M

    2016-06-21

    The geodesic (shortest) pathways through the potential energy landscape of a liquid can be thought of as defining what its dynamics would be if thermal noise were removed, revealing what we have called the "inherent dynamics" of the liquid. We show how these inherent paths can be located for a model liquid crystal former, showing, in the process, how the molecular mechanisms of translation and reorientation compare in the isotropic and nematic phases of these systems. These mechanisms turn out to favor the preservation of local orientational order even under macroscopically isotropic conditions (a finding consistent with the experimental observation of pseudonematic domains in these cases), but disfavor the maintenance of macroscopic orientational order, even in the nematic phase. While the most efficient nematic pathways that maintain nematic order are indeed shorter than those that do not, it is apparently difficult for the system to locate these paths, suggesting that molecular motion in liquid-crystal formers is dynamically frustrated, and reinforcing the sense that there are strong analogies between liquid crystals and supercooled liquids. PMID:27334177

  4. Cellular heterogeneity mediates inherent sensitivity–specificity tradeoff in cancer targeting by synthetic circuits

    PubMed Central

    Morel, Mathieu; Shtrahman, Roman; Rotter, Varda; Nissim, Lior; Bar-Ziv, Roy H.

    2016-01-01

    Synthetic gene circuits are emerging as a versatile means to target cancer with enhanced specificity by combinatorial integration of multiple expression markers. Such circuits must also be tuned to be highly sensitive because escape of even a few cells might be detrimental. However, the error rates of decision-making circuits in light of cellular variability in gene expression have so far remained unexplored. Here, we measure the single-cell response function of a tunable logic AND gate acting on two promoters in heterogeneous cell populations. Our analysis reveals an inherent tradeoff between specificity and sensitivity that is controlled by the AND gate amplification gain and activation threshold. We implement a tumor-mimicking cell-culture model of cancer cells emerging in a background of normal ones, and show that molecular parameters of the synthetic circuits control specificity and sensitivity in a killing assay. This suggests that, beyond the inherent tradeoff, synthetic circuits operating in a heterogeneous environment could be optimized to efficiently target malignant state with minimal loss of specificity. PMID:27385823

  5. An inherent anti-scatter detector for megavoltage x-ray imaging

    NASA Astrophysics Data System (ADS)

    Teymurazyan, A.; Pang, G.

    2013-03-01

    Scattered x-rays are detrimental to the image quality of x-ray transmission radiography. Anti-scatter grids have been developed for kilovoltage (kV) x-ray imaging but are impractical to use for megavoltage (MV) x-ray imaging in radiation therapy. Our goal is to develop a new approach that uses an inherent anti-scatter detector for scatter reduction in MV x-ray imaging. A Monte Carlo simulation has been conducted to evaluate the response of a recently proposed Čerenkov electronic portal imaging device (CPID) to scattered x-rays. The proposed detector consists of a matrix of optical fibers aligned with the incident x-rays and coupled to an active matrix flat panel imager for image readout. The effects of scatter on the signal and noise of the CPID in comparison with those of conventional electronic portal imaging devices (EPIDs) have been investigated. It has been found that the CPID is ∼50% less sensitive to scattered x-rays than conventional EPIDs at 6 MV. The differential signal to noise ratio is also improved by up to 30% in the CPID. The results of our simulations have demonstrated that the recently proposed CPID system is an inherent anti-scatter detector, the first of this kind, for MV x-ray imaging.

  6. Iodine content in bread, milk and the retention of inherent iodine in commonly used Indian recipes.

    PubMed

    Longvah, T; Toteja, G S; Upadhyay, A

    2013-01-15

    Iodine deficiency disorders (IDD) is still a major public health problem and iodized salt remains the most effective means to control IDD in India. Few reports indicate that vegans have inadequate iodine intake while at the same time concerns are being raised on the implementation of universal salt iodization in the country. Therefore, we investigated the iodine content in bread, milk and commonly used Indian recipes prepared without iodized salt and the retention of inherent iodine therein. Results showed considerable iodine content in bread (25 μg/100g) and milk (303 μg/L) as a positive fallout of universal salt iodization. Iodine content in 38 vegetarian recipes prepared without iodized salt was very low (2.9 ± 2.4 μg/100g). Retention of inherent iodine (65.6 ± 15.4%) and iodine from iodized salt (76.7 ± 10.3%) in the same recipes was comparable. Thus, universal salt iodization programme remains the single most important source of dietary iodine for the Indian population. PMID:23122074

  7. Inherent structure energy is a good indicator of molecular mobility in glasses.

    PubMed

    Helfferich, Julian; Lyubimov, Ivan; Reid, Daniel; de Pablo, Juan J

    2016-07-01

    Glasses produced via physical vapor deposition can display greater kinetic stability and lower enthalpy than glasses prepared by liquid cooling. While the reduced enthalpy has often been used as a measure of the stability, it is not obvious whether dynamic measures of stability provide the same view. Here, we study dynamics in vapor-deposited and liquid-cooled glass films using molecular simulations of a bead-spring polymer model as well as a Lennard-Jones binary mixture in two and three dimensions. We confirm that the dynamics in vapor-deposited glasses is indeed slower than in ordinary glasses. We further show that the inherent structure energy is a good reporter of local dynamics, and that aged systems and glasses prepared by cooling at progressively slower rates exhibit the same behavior as vapor-deposited materials when they both have the same inherent structure energy. These findings suggest that the stability inferred from measurements of the energy is also manifested in dynamic observables, and they strengthen the view that vapor deposition processes provide an effective strategy for creation of stable glasses. PMID:27334679

  8. Importance of the inherent and the relative surface energies in generating patterned layer in a solution process

    NASA Astrophysics Data System (ADS)

    Kim, Do-Kyung; Kwon, Hyeok Bin; Park, Hongsik; Choe, Eunji; Bae, Jin-Hyuk; Park, Jaehoon; Song, Seong-Ho

    2016-03-01

    We report the importance of the inherent and the relative surface energies in generating a patterned organic semiconductor layer through a solution process. The inherent and the relative surface energies of the substrate can be effectively controlled using polydimethylsiloxane in combination with an UV/ozone treatment. The controlled inherent surface energy in each region, as well as the high-order difference of relative surface energy, plays a significant role in generating the patterned layer. In addition, the patterned metal-semiconductor-metal (MSM) structure shows a lower lateral current than the non-patterned MSM structure because the current path is limited.

  9. The contribution of apparent and inherent usability to a user's satisfaction in a searching and browsing task on the Web.

    PubMed

    Fu, Limin; Salvendy, Gavriel

    2002-05-15

    Previous research found that apparent and inherent usability had big influences on user's acceptance of computer systems. This research extended these findings to the area of user's satisfaction. The study investigated the impact of inherent and apparent usability on user's satisfaction of Web page designs while the two main tasks on the World Wide Web, searching and browsing, were performed. The results indicated that inherent usability was the main factor contributing to user's satisfaction in both searching and browsing. General principles and specific recommendations for the design and evaluation of Web page designs are derived from these findings. PMID:12061966

  10. Safety Systems

    ERIC Educational Resources Information Center

    Halligan, Tom

    2009-01-01

    Colleges across the country are rising to the task by implementing safety programs, response strategies, and technologies intended to create a secure environment for teachers and students. Whether it is preparing and responding to a natural disaster, health emergency, or act of violence, more schools are making campus safety a top priority. At…

  11. Solidifying Safety

    NASA Technical Reports Server (NTRS)

    Covault, Craig

    2003-01-01

    Contents include the following: 1. Solidifying Safety: NASA s new safety organization spools up, as the 1SS program grapples with long-term risk. 2. Earth to Orbit O'Keefe telling skeptical lawmakers Orbital Space Plan (OSP) will cover exploration vision. China's rapid pace.

  12. Safety First

    ERIC Educational Resources Information Center

    Taft, Darryl

    2011-01-01

    Ned Miller does not take security lightly. As director of campus safety and emergency management at the Des Moines Area Community College (DMACC), any threat requires serious consideration. As community college administrators adopt a more proactive approach to campus safety, many institutions are experimenting with emerging technologies, including…

  13. Quick and Easy Measurements of the Inherent Optical Property of Water by Laser

    SciTech Connect

    Izadi, Dina; Hajiesmaeilbaigi, Fereshteh

    2009-04-19

    To generate realistic images of natural waters, one must consider in some detail the interaction of light with the water body. The reflectance and attenuation coefficient of the second harmonic of Nd:YAG laser light through distilled water and a sample of water from the Oman Sea were measured in a solid-state laser laboratory to estimate inherent optical properties of natural waters. These measurements determined the bottom conditions and the impurities of the water. The water's reflectivity varied depending on the angle of incidence, height of the laser from water surface, wavelength of laser light, radiant intensities, and depth of water. In these experiments laser light propagated through the water nonlinearly, and different reflectance showed different bottom slopes. The differences among various water samples were obtained taking into account the exponential equation in attenuation coefficient versus depth graphs.

  14. Deriving inherent optical properties and associated uncertainties for the Dutch inland waters during the Eagle Campaign

    NASA Astrophysics Data System (ADS)

    Salama, M. S.; Su, Z.; Mannaerts, C. M.; Verhoef, W.

    2009-03-01

    During the Eagle 2006 campaign intensive in-situ and air/space borne measurements were carried out over the Wolderwijd and Veluwemeer natural waters in the Netherlands. In this paper, we modify the GSM semi-analytical inversion model for these lakes to derive inherent optical properties (IOPs) and their spectral dependencies from air and space borne data. Uncertainties of the derived IOPs are estimated using a nonlinear regression technique. The modified model succeeded in deriving accurate estimates of IOPs with R2 higher than 0.9 and RMSE values equal to 0.12 and 0.05 for absorption and scattering coefficients, respectively. Finally, we show that the uncertainty of derived absorption coefficients is slightly independent of absorption's magnitude. While the uncertainty of all derived IOPs increases with water turbidity.

  15. All-optical design for inherently energy-conserving reversible gates and circuits.

    PubMed

    Cohen, Eyal; Dolev, Shlomi; Rosenblit, Michael

    2016-01-01

    As energy efficiency becomes a paramount issue in this day and age, reversible computing may serve as a critical step towards energy conservation in information technology. The inputs of reversible computing elements define the outputs and vice versa. Some reversible gates such as the Fredkin gate are also universal; that is, they may be used to produce any logic operation. It is possible to find physical representations for the information, so that when processed with reversible logic, the energy of the output is equal to the energy of the input. It is suggested that there may be devices that will do that without applying any additional power. Here, we present a formalism that may be used to produce any reversible logic gate. We implement this method over an optical design of the Fredkin gate, which utilizes only optical elements that inherently conserve energy. PMID:27113510

  16. Evaluation of different in vitro assays of inherent sensitivity as predictors of radiotherapy response

    SciTech Connect

    Schwartz, J.L. Chicago Univ., IL . Medical Center); Beckett, M.A.; Mustafi, R.; Weichselbaum, R.R. . Medical Center); Vaughan, A.T.M. . Stritch School of Medicine)

    1991-01-01

    The inherent sensitivity of cells within a tumor plays an important role in the response of the tumor to radiotherapy. Clonogenic assays show that cells established from in-field radiotherapy failures are significantly more resistant to radiation than cell lines established from pre-treatment samples. Clonogenic assays fail to predict tumor response to radiotherapy, however. The failure might be due to the small sample size in this study, or the complicating factors of staging, surgery, and chemotherapy, and/or in vivo selection by radiotherapy for resistant tumor cells. In vitro selection for resistant cell lines does not appear to be a complicating factor. Nonclonogenic assays such as those that measure DNA strand break rejoining rates (filter elution, pulse-field gel electrophoresis) or chromosome structure (flow cytometric analysis) show promise as alternative rapid assays of radiation sensitivity and possibly tumor response. 16 refs., 2 figs.

  17. Biomaterial Approaches to Enhancing Neurorestoration after Spinal Cord Injury: Strategies for Overcoming Inherent Biological Obstacles

    PubMed Central

    Siebert, Justin R.; Eade, Amber M.; Osterhout, Donna J.

    2015-01-01

    While advances in technology and medicine have improved both longevity and quality of life in patients living with a spinal cord injury, restoration of full motor function is not often achieved. This is due to the failure of repair and regeneration of neuronal connections in the spinal cord after injury. In this review, the complicated nature of spinal cord injury is described, noting the numerous cellular and molecular events that occur in the central nervous system following a traumatic lesion. In short, postinjury tissue changes create a complex and dynamic environment that is highly inhibitory to the process of neural regeneration. Strategies for repair are outlined with a particular focus on the important role of biomaterials in designing a therapeutic treatment that can overcome this inhibitory environment. The importance of considering the inherent biological response of the central nervous system to both injury and subsequent therapeutic interventions is highlighted as a key consideration for all attempts at improving functional recovery. PMID:26491685

  18. All-optical design for inherently energy-conserving reversible gates and circuits

    PubMed Central

    Cohen, Eyal; Dolev, Shlomi; Rosenblit, Michael

    2016-01-01

    As energy efficiency becomes a paramount issue in this day and age, reversible computing may serve as a critical step towards energy conservation in information technology. The inputs of reversible computing elements define the outputs and vice versa. Some reversible gates such as the Fredkin gate are also universal; that is, they may be used to produce any logic operation. It is possible to find physical representations for the information, so that when processed with reversible logic, the energy of the output is equal to the energy of the input. It is suggested that there may be devices that will do that without applying any additional power. Here, we present a formalism that may be used to produce any reversible logic gate. We implement this method over an optical design of the Fredkin gate, which utilizes only optical elements that inherently conserve energy. PMID:27113510

  19. Remote-Sensing Reflectance and Inherent Optical Properties for Optically Deep Waters: A Revisit

    NASA Technical Reports Server (NTRS)

    Lee, Zhong-Ping; Carder, Kendall L.; Du, Ke-Ping

    2001-01-01

    Remote-sensing reflectance (r(rs)) is defined as the ratio of upwelling radiance to downwelling irradiance. Relationships between remote-sensing reflectance and inherent optical properties serve as the basis for ocean-color modeling, as well as for spectral deduction of oceanic constituents through analytical/semi-analytical models of ocean color. A decade ago, a simple and concise formula based on Monte Carlo simulations was developed by relating rrs to a property u, the ratio of backscattering (b(b)) to the sum of absorption (a) and backscattering (u = b(b)/(a+b(b))). This relationship generally ignored the shape differences in phase functions between molecular scattering and particle scattering. In this study, the relationship is updated with separate parameters for molecular and particle scattering, based on the Radiative Transfer Equation through use of Hydrolight numerical solutions. The new approach fits r(rs) better than an earlier traditional formula, for both clear and turbid waters.

  20. All-optical design for inherently energy-conserving reversible gates and circuits

    NASA Astrophysics Data System (ADS)

    Cohen, Eyal; Dolev, Shlomi; Rosenblit, Michael

    2016-04-01

    As energy efficiency becomes a paramount issue in this day and age, reversible computing may serve as a critical step towards energy conservation in information technology. The inputs of reversible computing elements define the outputs and vice versa. Some reversible gates such as the Fredkin gate are also universal; that is, they may be used to produce any logic operation. It is possible to find physical representations for the information, so that when processed with reversible logic, the energy of the output is equal to the energy of the input. It is suggested that there may be devices that will do that without applying any additional power. Here, we present a formalism that may be used to produce any reversible logic gate. We implement this method over an optical design of the Fredkin gate, which utilizes only optical elements that inherently conserve energy.

  1. New classes of integrals inherent in the mathematical structure of extended equations describing superconducting systems

    NASA Astrophysics Data System (ADS)

    Gonczarek, Ryszard; Krzyzosiak, Mateusz; Gonczarek, Adam; Jacak, Lucjan

    2015-06-01

    In this paper, we discuss the mathematical structure of the s-wave superconducting gap and other quantitative characteristics of superconducting systems. In particular, we evaluate and discuss integrals inherent in fundamental equations describing superconducting systems. The results presented here extend the approach formulated by Abrikosov and Maki, which was restricted to the first-order expansion. A few infinite families of integrals are derived and allow us to express the fundamental equations by means of analytic formulas. They can be then exploited in order to find some quantitative characteristics of superconducting systems by the method of successive approximations. We show that the results can be applied to some modern formalisms in order to study high-Tc superconductors and other superconducting materials of the new generation.

  2. Inherently distorted heme as a novel tool for myoglobin-based oxygen carrier.

    PubMed

    Neya, Saburo; Kawaguchi, Akira T

    2012-02-01

    The two types of artificial myoglobins (Mbs) containing inherently distorted α-ethyl-2,4-dimethyldeuteroheme and undistorted 2,4-dimethyldeuteroheme were prepared to examine the influence of nonplanar heme deformation on the reactivity of Mb. In ferrous deoxy proteins, the paramagnetic proton nuclear magnetic resonance spectra showed that the deformed heme caused a 3.2-ppm lower-field shift of the proximal histidine signal, indicating a larger iron displacement from the heme plane upon the nonplanar deformation. The Mb with the nonplanar heme exhibited a markedly lower oxygen affinity as compared with the Mb containing the planar heme. The result suggests the utility of heme distortion to design the Mb-based oxygen carrier. PMID:21501194

  3. Inherent and Apparent Scattering Properties of Coated or Uncoated Spheres Embedded in an Absorbing Host Medium

    NASA Technical Reports Server (NTRS)

    Yang, P.; Gao, B.-C.; Wiscombe, W. J.; Mishchenko, M. I.; Platnick, S.; Huang, H.-L.; Baum, B. A.; Hu, Y. X.; Winkler, D,; Tsay, S.-C.; Lau, William K. M. (Technical Monitor)

    2001-01-01

    The conventional Lorenz-Mie formalism is extended to the scattering process associated with a coated sphere embedded in an absorbing medium. It is shown that apparent and inherent scattering cross sections of a scattering particle, which are identical in the case of transparent host medium, are different if the host medium is absorptive. Here the inherent single-scattering properties are derived from the near-field information whereas the corresponding apparent counterparts are derived from the far-field asymptotic form of the scattered wave with scaling of host absorption that is assumed to be in an exponential form. The formality extinction and scattering efficiencies defined in the same manner as in the conventional sense can be unbounded. For a nonabsorptive particle embedded in an absorbing medium, the effect of host absorption on the phase matrix elements associated with polarization is significant. This effect, however, is largely reduced for strongly absorptive particles such as soot. For soot particles coated with water, the impurity can substantially reduce the single-scattering albedo of the particle if the size parameter is small. For water-coating soot and hollow ice spheres, it is shown that the phase matrix elements -P(sub 12)/P(sub 11) and P(sub 33)/P(sub 11) are unique if the shell is thin, as compared with the case for thick shell. Furthermore, the radiative transfer equation regarding a multidisperse particle system in an absorbing medium is discussed. It is illustrated that the conventional computation algorithms can be applied to solve the multiple scattering process if the scaled apparent single-scattering properties are applied.

  4. Inherent and Acquired Resistance to Paclitaxel in Hepatocellular Carcinoma: Molecular Events Involved

    PubMed Central

    Meena, Avtar Singh; Sharma, Aanchal; Kumari, Ratna; Mohammad, Naoshad; Singh, Shivendra Vikram; Bhat, Manoj Kumar

    2013-01-01

    Hepatocellular carcinoma (HCC) is a primary malignancy of the liver and is a major cause of cancer related deaths worldwide. Only 10 to 20% of HCC can be surgically excised. Therefore, chemotherapeutic intervention and treatment is essential for achieving favorable prognosis. However, therapeutic outcome of chemotherapy is generally poor owing to inherent resistance of cancer cells to the treatment or due to development of acquired resistance. To differentiate and delineate the molecular events, we developed drug resistant Hep3B cells (DRC) by treating cells with the increasing concentration of paclitaxel. We also developed a unique single cell clone of Hep3B cells (SCC) by selecting single cell colonies and screening them for resistant phenotype. Interestingly, both DRC and SCC were resistant to paclitaxel in comparison to parental Hep3B cells. We analyzed the contributory factors that may be involved in the development of resistance. As expected, level of P-glycoprotein (P-gp) was elevated in DRC. In addition, Caveolin-1 (Cav-1), Fatty acid synthase (FASN) and Cytochrome P450 (CYP450) protein levels were elevated in DRC whereas in SCC, FASN and CYP450 levels were elevated. Downregulation of these molecules by respective siRNAs and/or by specific pharmacological inhibitors resensitized cells to paclitaxel. Interestingly, these drug resistant cells were also less sensitive to vinblastine, doxorubicin and methotrexate with the exception of cisplatin. Our results suggested that differential levels of P-gp, Cav-1 and FASN play a major role in acquired resistant phenotype whereas FASN level was associated with the presentation of inherent resistant phenotype in HCC. PMID:23613870

  5. The inherent weaknesses in industrial control systems devices; hacking and defending SCADA systems

    NASA Astrophysics Data System (ADS)

    Bianco, Louis J.

    The North American Electric Reliability Corporation (NERC) is about to enforce their NERC Critical Infrastructure Protection (CIP) Version Five and Six requirements on July 1st 2016. The NERC CIP requirements are a set of cyber security standards designed to protect cyber assets essential the reliable operation of the electric grid. The new Version Five and Six requirements are a major revision to the Version Three (currently enforced) requirements. The new requirements also bring substations into scope alongside Energy Control Centers. When the Version Five requirements were originally drafted they were vague, causing in depth discussions throughout the industry. The ramifications of these requirements has made owners look at their systems in depth, questioning how much money it will take to meet these requirements. Some owners saw backing down from routable networks to non-routable as a means to save money as they would be held to less requirements within the standards. Some owners saw removing routable connections as a proper security move. The purpose of this research was to uncover the inherent weaknesses in Industrial Control Systems (ICS) devices; to show how ICS devices can be hacked and figure out potential protections for these Critical Infrastructure devices. In addition, this research also aimed to validate the decision to move from External Routable connectivity to Non-Routable connectivity, as a security measure and not as a means of savings. The results reveal in order to ultimately protect Industrial Control Systems they must be removed from the Internet and all bi-directional external routable connections must be removed. Furthermore; non-routable serial connections should be utilized, and these non-routable serial connections should be encrypted on different layers of the OSI model. The research concluded that most weaknesses in SCADA systems are due to the inherent weaknesses in ICS devices and because of these weaknesses, human intervention is

  6. Contrasting Inherent Optical Properties and Carbon Metabolism Between Five Northeastern (USA) Estuary-plume Systems

    NASA Technical Reports Server (NTRS)

    Vandemark, Doug; Salisbury, Joe; Hunt, Chris; McGillis, Wade R.

    2004-01-01

    We have recently developed the ability to rapidly assess Surface inherent optical properties (IOP), oxygen concentration and pCO2 in estuarine-plume systems using flow-through instrumentation. During the summer of 2004, several estuarine-plume systems were surveyed which include the Pleasant (ME), Penobscot (ME), Kennebec-Androscoggin (ME), Merrimack (NH-MA) and Hudson (NY). Continuous measurements of surface chlorophyll and colored dissolved organic carbon (CDOM) fluorescence, beam attenuation, temperature, salinity, oxygen and pC02 were taken at each system along a salinity gradient from fresh water to near oceanic endmembers. CTD and IOP profiles were also taken at predetermined surface salinity intervals. These were accompanied by discrete determinations of chlorophyll (HPLC and fluorometric), total suspended solids (TSS), dissolved organic carbon (DOC) and alkalinity. IOP data were calibrated using chlorophyll, DOC and TSS data to enable the retrieval of these constituents from IOP data. Considerable differences in the data sets were observed between systems. These ranged from the DOC-enriched, strongly heterotrophic Pleasant River System to the high-chlorophyll autotrophic Merrimack River System. Using pCO2 and oxygen saturation measurements as proxies for water column metabolism, distinct relationships were found between trophic status and inherent optical properties. The nature of these relationships varies between systems and is likely a function of watershed and estuarine attributes including carbon and nutrient loading, in-situ production and related autochthonous inputs of DOC and alkalinity. Our results suggest that IOP data may contain significant information about the trophic status of estuarine and plume systems.

  7. Thick Acellular Heart Extracellular Matrix with Inherent Vasculature: A Potential Platform for Myocardial Tissue Regeneration

    PubMed Central

    Sarig, Udi; Au-Yeung, Gigi C.T.; Wang, Yao; Bronshtein, Tomer; Dahan, Nitsan; Boey, Freddy Y.C.; Venkatraman, Subbu S.

    2012-01-01

    The decellularization of porcine heart tissue offers many opportunities for the production of physiologically relevant myocardial mimetic scaffolds. Earlier, we reported the successful isolation of a thin porcine cardiac extracellular matrix (pcECM) exhibiting relevant bio-mechanical properties for myocardial tissue engineering. Nevertheless, since native cardiac tissue is much thicker, such thin scaffolds may offer limited regeneration capacity. However, generation of thicker myocardial mimetic tissue constructs is hindered by diffusion limitations (∼100 μm), and the lack of a proper vascular-like network within these constructs. In our present work, we focused on optimizing the decellularization procedure for thicker tissue slabs (10–15 mm), while retaining their inherent vasculature, and on characterizing the resulting pcECM. The trypsin/Triton-based perfusion procedure that resulted in a nonimmunogenic and cell-supportive pcECM was found to be more effective in cell removal and in the preservation of fiber morphology and structural characteristics than stirring, sonication, or sodium dodecyl sulfate/Triton-based procedures. Mass spectroscopy revealed that the pcECM is mainly composed of ECM proteins with no apparent cellular protein remains. Mechanical testing indicated that the obtained pcECM is viscoelastic in nature and possesses the typical stress-strain profile of biological materials. It is stiffer than native tissue yet exhibits matched mechanical properties in terms of energy dissipation, toughness, and ultimate stress behavior. Vascular network functionality was maintained to the first three–four branches from the main coronary vessels. Taken together, these results reaffirm the efficiency of the decellularization procedure reported herein for yielding thick nonimmunogenic cell-supportive pcECM scaffolds, preserving both native tissue ultra-structural properties and an inherent vascular network. When reseeded with the appropriate progenitor

  8. ESTIMATION OF INHERENT OPTICAL PROPERTIES AND THE WATER QUALITY COMPONENTS IN THE NEUSE RIVER-PAMLICO SOUND ESTUARINE SYSTEM

    EPA Science Inventory

    Field observations carried out in the Neuse River-Pamlico Sound Estuarine System (NRE-PS), North Carolina, USA were used to develop optical algorithms for assessing inherent optical properties, IOPs (absorption and backscattering) associated with water quality components (WQC).

  9. Software safety

    NASA Technical Reports Server (NTRS)

    Leveson, Nancy

    1987-01-01

    Software safety and its relationship to other qualities are discussed. It is shown that standard reliability and fault tolerance techniques will not solve the safety problem for the present. A new attitude requires: looking at what you do NOT want software to do along with what you want it to do; and assuming things will go wrong. New procedures and changes to entire software development process are necessary: special software safety analysis techniques are needed; and design techniques, especially eliminating complexity, can be very helpful.

  10. Safety Tips.

    ERIC Educational Resources Information Center

    Nagel, Miriam C., Ed.

    1984-01-01

    Outlines a cooperative effort in Iowa to eliminate dangerous or unwanted chemicals from school science storerooms. Also reviews the Council of State Science Supervisor's safety program and discusses how to prevent cuts and punctures from jagged glass tubing. (JN)

  11. Food Safety

    MedlinePlus

    ... are four basic steps to food safety at home: Clean - always wash your fruits and vegetables, hands, counters, and cooking utensils. Separate - keep raw foods to themselves. Germs can spread from one food ...

  12. Applying neural networks to optimize instrumentation performance

    SciTech Connect

    Start, S.E.; Peters, G.G.

    1995-06-01

    Well calibrated instrumentation is essential in providing meaningful information about the status of a plant. Signals from plant instrumentation frequently have inherent non-linearities, may be affected by environmental conditions and can therefore cause calibration difficulties for the people who maintain them. Two neural network approaches are described in this paper for improving the accuracy of a non-linear, temperature sensitive level probe ised in Expermental Breeder Reactor II (EBR-II) that was difficult to calibrate.

  13. The nature of inherent bactericidal activity: insights from the nanotopology of three species of dragonfly

    NASA Astrophysics Data System (ADS)

    Mainwaring, David E.; Nguyen, Song Ha; Webb, Hayden; Jakubov, Timur; Tobin, Mark; Lamb, Robert N.; Wu, Alex H.-F.; Marchant, Richard; Crawford, Russell J.; Ivanova, Elena P.

    2016-03-01

    While insect wings are widely recognised as multi-functional, recent work showed that this extends to extensive bactericidal activity brought about by cell deformation and lysis on the wing nanotopology. We now quantitatively show that subtle changes to this topography result in substantial changes in bactericidal activity that are able to span an order of magnitude. Notably, the chemical composition of the lipid nanopillars was seen by XPS and synchrotron FTIR microspectroscopy to be similar across these activity differences. Modelling the interaction between bacterial cells and the wing surface lipids of 3 species of dragonflies, that inhabit similar environments, but with distinctly different behavioural repertoires, provided the relationship between surface structure and antibacterial functionality. In doing so, these principal behavioural patterns correlated with the demands for antimicrobial efficiency dictated by differences in their foraging strategies. This work now reveals a new feature in the design elegance of natural multi-functional surfaces as well providing insights into the bactericidal mechanism underlying inherently antimicrobial materials, while suggesting that nanotopology is related to the evolutionary development of a species through the demands of its behavioural repertoire. The underlying relationship between the processes of wetting, adhesion and capillarity of the lipid nanopillars and bactericidal efficiency suggests new prospects for purely mechano-responsive antibacterial surfaces.While insect wings are widely recognised as multi-functional, recent work showed that this extends to extensive bactericidal activity brought about by cell deformation and lysis on the wing nanotopology. We now quantitatively show that subtle changes to this topography result in substantial changes in bactericidal activity that are able to span an order of magnitude. Notably, the chemical composition of the lipid nanopillars was seen by XPS and synchrotron

  14. Self-aligned Schwann cell monolayers demonstrate an inherent ability to direct neurite outgrowth

    NASA Astrophysics Data System (ADS)

    Seggio, A. M.; Narayanaswamy, A.; Roysam, B.; Thompson, D. M.

    2010-08-01

    In vivo nerve guidance channel studies have identified Schwann cell (SC) presence as an integral factor in axonal number and extension in an injury site, and in vitro studies have provided evidence that oriented SCs can direct neurite outgrowth. However, traditional methods used to create oriented SC monolayers (e.g. micropatterns/microtopography) potentially introduce secondary guidance cues to the neurons that are difficult to de-couple. Although SCs expanded on uniform laminin-coated coverslips lack a global orientation, the monolayers contain naturally formed regions of locally oriented cells that can be used to investigate SC-mediated neurite guidance. In this work, novel image analysis techniques have been developed to quantitatively assess local neurite orientation with respect to the underlying regional orientation of the Schwann cell monolayer. Results confirm that, in the absence of any secondary guidance cues, a positive correlation exists between neurite outgrowth and regional orientation of the SC monolayer. Thus, SCs alone possess an inherent ability to direct neurite outgrowth, and expansion of the co-culture-based quantitative method described can be used to further deconstruct specific biomolecular mechanisms of neurite guidance.

  15. Generalized ocean color inversion model for retrieving marine inherent optical properties.

    PubMed

    Werdell, P Jeremy; Franz, Bryan A; Bailey, Sean W; Feldman, Gene C; Boss, Emmanuel; Brando, Vittorio E; Dowell, Mark; Hirata, Takafumi; Lavender, Samantha J; Lee, ZhongPing; Loisel, Hubert; Maritorena, Stéphane; Mélin, Fréderic; Moore, Timothy S; Smyth, Timothy J; Antoine, David; Devred, Emmanuel; d'Andon, Odile Hembise Fanton; Mangin, Antoine

    2013-04-01

    Ocean color measured from satellites provides daily, global estimates of marine inherent optical properties (IOPs). Semi-analytical algorithms (SAAs) provide one mechanism for inverting the color of the water observed by the satellite into IOPs. While numerous SAAs exist, most are similarly constructed and few are appropriately parameterized for all water masses for all seasons. To initiate community-wide discussion of these limitations, NASA organized two workshops that deconstructed SAAs to identify similarities and uniqueness and to progress toward consensus on a unified SAA. This effort resulted in the development of the generalized IOP (GIOP) model software that allows for the construction of different SAAs at runtime by selection from an assortment of model parameterizations. As such, GIOP permits isolation and evaluation of specific modeling assumptions, construction of SAAs, development of regionally tuned SAAs, and execution of ensemble inversion modeling. Working groups associated with the workshops proposed a preliminary default configuration for GIOP (GIOP-DC), with alternative model parameterizations and features defined for subsequent evaluation. In this paper, we: (1) describe the theoretical basis of GIOP; (2) present GIOP-DC and verify its comparable performance to other popular SAAs using both in situ and synthetic data sets; and, (3) quantify the sensitivities of their output to their parameterization. We use the latter to develop a hierarchical sensitivity of SAAs to various model parameterizations, to identify components of SAAs that merit focus in future research, and to provide material for discussion on algorithm uncertainties and future emsemble applications. PMID:23545956

  16. A multimethod examination of the relationship between coaching behavior and athletes' inherent self-talk.

    PubMed

    Zourbanos, Nikos; Hatzigeorgiadis, Antonis; Tsiakaras, Nikos; Chroni, Stiliani; Theodorakis, Yannis

    2010-12-01

    The aim of the present research was to investigate the relationship between coaching behavior and athletes' inherent self-talk (ST). Three studies were conducted. The first study tested the construct validity of the Coaching Behavior Questionnaire (CBQ) in the Greek language, and provided support for its original factor structure. The second study examined the relationships between coaching behavior and athletes' ST in field, with two different samples. The results showed that supportive coaching behavior was positively related to positive ST (in one sample) and negatively related to negative ST (in both samples), whereas negative coaching behavior was negatively related to positive ST (in one sample) and positively related to negative ST (in both samples). Finally, the third study examined the relationships experimentally, to produce evidence regarding the direction of causality. The results showed that variations in coaching behavior affected participants' ST. Overall, the results of the present investigation provided considerable evidence regarding the links between coaching behavior and athletes' ST and suggested that coaches may have an impact on athletes' thoughts. PMID:21282837

  17. Coke gasification: the influence and behavior of inherent catalytic mineral matter

    SciTech Connect

    Mihaela Grigore; Richard Sakurovs; David French; Veena Sahajwalla

    2009-04-15

    Gasification of coke contributes to its degradation in the blast furnace. In this study, the effect of gasification on the inherent catalytic minerals in cokes and their reciprocal influence on gasification are investigated. The catalytic mineral phases identified in the cokes used in this study were metallic iron, iron sulfides, and iron oxides. Metallic iron and pyrrhotite were rapidly oxidized during gasification to iron oxide. The catalysts had a strong influence on the apparent rates at the initial stages of reaction. As gasification proceeds, their effect on the reaction rate diminishes as a result of reducing the surface contact between catalyst and carbon matrix because of carbon consumption around the catalyst particles; with extended burnout the reactivity of the coke becomes increasingly dependent on surface area. The reaction rate in the initial stages was also influenced by the particle size of the catalytic minerals; for a given catalytic iron level, the cokes whose catalytic minerals were more finely dispersed had a higher apparent reaction rate than cokes containing larger catalytic particles. Iron, sodium, and potassium in the amorphous phase did not appear to affect the reaction rate. 40 refs., 16 figs., 6 tabs.

  18. A robotic apparatus that dictates torque fields around joints without affecting inherent joint dynamics.

    PubMed

    Oytam, Yalchin; Lloyd, David; Reid, Campbell S; de Rugy, Aymar; Carson, Richard G

    2010-10-01

    This manuscript describes how motor behaviour researchers who are not at the same time expert roboticists may implement an experimental apparatus, which has the ability to dictate torque fields around a single joint on one limb or single joints on multiple limbs without otherwise interfering with the inherent dynamics of those joints. Such an apparatus expands the exploratory potential of the researcher wherever experimental distinction of factors may necessitate independent control of torque fields around multiple limbs, or the shaping of torque fields of a given joint independently of its plane of motion, or its directional phase within that plane. The apparatus utilizes torque motors. The challenge with torque motors is that they impose added inertia on limbs and thus attenuate joint dynamics. We eliminated this attenuation by establishing an accurate mathematical model of the robotic device using the Box-Jenkins method, and cancelling out its dynamics by employing the inverse of the model as a compensating controller. A direct measure of the remnant inertial torque as experienced by the hand during a 50 s period of wrist oscillations that increased gradually in frequency from 1.0 to 3.8 Hz confirmed that the removal of the inertial effect of the motor was effectively complete. PMID:20728232

  19. Effect of inherent deformations of leadframes on bleedability of plastic dip

    NASA Astrophysics Data System (ADS)

    Kerk, S. L.; Tay, S. C.; Hu, S. J.

    1989-03-01

    Variance formed between the mold plate and the leadframe causes resin bleed on the leads of the plastic 40L Dual In-Line Package (PDIP 40L). Resin bleed affects the solderability of the package. The mechanical stamping method used in the production of the copper leadframes causes dented deformation at the edge of the leads of the leadframe. A perfect uniform flatness on the surface of the copper leadframe is also not possible. Study is carried out to investigate the effect of these inherent deformations of stamped copper leadframes' surface on the resin bleed-out of the plastic DIP. The results show that two types of bleed rejects occurred because of the stamping induced deformation found at the edge of the leads of the copper leadframes and the non uniform flatness of the surface on the copper leadframes. Resin bleedability and non-solderability can be eliminated when chemically etched copper leadframes are used for the plastic Dual-In-Line Packages.

  20. Computability, Gödel's incompleteness theorem, and an inherent limit on the predictability of evolution.

    PubMed

    Day, Troy

    2012-04-01

    The process of evolutionary diversification unfolds in a vast genotypic space of potential outcomes. During the past century, there have been remarkable advances in the development of theory for this diversification, and the theory's success rests, in part, on the scope of its applicability. A great deal of this theory focuses on a relatively small subset of the space of potential genotypes, chosen largely based on historical or contemporary patterns, and then predicts the evolutionary dynamics within this pre-defined set. To what extent can such an approach be pushed to a broader perspective that accounts for the potential open-endedness of evolutionary diversification? There have been a number of significant theoretical developments along these lines but the question of how far such theory can be pushed has not been addressed. Here a theorem is proven demonstrating that, because of the digital nature of inheritance, there are inherent limits on the kinds of questions that can be answered using such an approach. In particular, even in extremely simple evolutionary systems, a complete theory accounting for the potential open-endedness of evolution is unattainable unless evolution is progressive. The theorem is closely related to Gödel's incompleteness theorem, and to the halting problem from computability theory. PMID:21849390

  1. The nature of inherent bactericidal activity: insights from the nanotopology of three species of dragonfly.

    PubMed

    Mainwaring, David E; Nguyen, Song Ha; Webb, Hayden; Jakubov, Timur; Tobin, Mark; Lamb, Robert N; Wu, Alex H-F; Marchant, Richard; Crawford, Russell J; Ivanova, Elena P

    2016-03-28

    While insect wings are widely recognised as multi-functional, recent work showed that this extends to extensive bactericidal activity brought about by cell deformation and lysis on the wing nanotopology. We now quantitatively show that subtle changes to this topography result in substantial changes in bactericidal activity that are able to span an order of magnitude. Notably, the chemical composition of the lipid nanopillars was seen by XPS and synchrotron FTIR microspectroscopy to be similar across these activity differences. Modelling the interaction between bacterial cells and the wing surface lipids of 3 species of dragonflies, that inhabit similar environments, but with distinctly different behavioural repertoires, provided the relationship between surface structure and antibacterial functionality. In doing so, these principal behavioural patterns correlated with the demands for antimicrobial efficiency dictated by differences in their foraging strategies. This work now reveals a new feature in the design elegance of natural multi-functional surfaces as well providing insights into the bactericidal mechanism underlying inherently antimicrobial materials, while suggesting that nanotopology is related to the evolutionary development of a species through the demands of its behavioural repertoire. The underlying relationship between the processes of wetting, adhesion and capillarity of the lipid nanopillars and bactericidal efficiency suggests new prospects for purely mechano-responsive antibacterial surfaces. PMID:26935293

  2. High homogeneity 25 cm low-energy rf ion source with inherent electron compensation

    NASA Astrophysics Data System (ADS)

    Dudin, S. V.; Rafalskyi, D. V.; Zykov, A. V.

    2010-08-01

    A 25 cm single-grid low-energy rf ion source with inherent electron compensation is described and characterized. Measurements were carried out using Ar and CF4 filling gas. The dependence of the ion beam current to the target as well as the current partition between the beam fast and slow ions on the rf discharge pressure for both filling gases is discussed. The unique ability of generation of coinciding ion and electron flows is demonstrated and the measured ion and electron energy distribution functions are presented as well. The developed broad ion beam source is able of providing 0.5-5 mA/cm2 current density in the low ion energy range of 50-250 eV, with possibility of independent current density and energy control. It is shown that complementing the rf plasma source with a profiling electrode allows for CF4 ion source operation attaining ±5% ion beam uniformity over 250 mm in diameter. The presented CF4 etching test results exhibit the possibility of highly directional anisotropic Si and SiO2 etching utilizing the developed single grid rf ion source.

  3. Visual analytics of inherently noisy crowdsourced data on ultra high resolution displays

    NASA Astrophysics Data System (ADS)

    Huynh, Andrew; Ponto, Kevin; Lin, Albert Yu-Min; Kuester, Falko

    The increasing prevalence of distributed human microtasking, crowdsourcing, has followed the exponential increase in data collection capabilities. The large scale and distributed nature of these microtasks produce overwhelming amounts of information that is inherently noisy due to the nature of human input. Furthermore, these inputs create a constantly changing dataset with additional information added on a daily basis. Methods to quickly visualize, filter, and understand this information over temporal and geospatial constraints is key to the success of crowdsourcing. This paper present novel methods to visually analyze geospatial data collected through crowdsourcing on top of remote sensing satellite imagery. An ultra high resolution tiled display system is used to explore the relationship between human and satellite remote sensing data at scale. A case study is provided that evaluates the presented technique in the context of an archaeological field expedition. A team in the field communicated in real-time with and was guided by researchers in the remote visual analytics laboratory, swiftly sifting through incoming crowdsourced data to identify target locations that were identified as viable archaeological sites.

  4. Structure-Inherent Targeting of NIR Fluorophores for Parathyroid and Thyroid Gland Imaging

    PubMed Central

    Hyun, Hoon; Park, Min Ho; Owens, Eric A.; Wada, Hideyuki; Henary, Maged; Handgraaf, Hein J.M.; Vahrmeijer, Alexander L.; Frangioni, John V.; Choi, Hak Soo

    2014-01-01

    The typical method for creating targeted contrast agents requires covalent conjugation of separate targeting and fluorophore domains. In this study, we demonstrate that it is possible create tissue-specific near-infrared fluorophores using the inherent chemical structure. Thus, a single compact molecule performs both targeting and imaging. We use this strategy to solve a major problem in head/neck surgery, the identification and preservation of parathyroid and thyroid glands. We synthesized 700-nm and 800-nm halogenated fluorophores that show high uptake in the specific glands after a single intravenous injection of only 0.06 mg kg−1 in a pig. Using a dual-channel near-infrared imaging system, we demonstrate the real-time, high-sensitivity, unambiguous identification of parathyroid and thyroid glands simultaneously in the context of blood and surrounding soft tissue. This novel technology lays the foundation for head/neck surgery performed with increased precision and efficiency, and potentially lowers morbidity, and a general strategy for targeted near-infrared fluorophore development. PMID:25559343

  5. Cometabolic degradation of organic wastewater micropollutants by activated sludge and sludge-inherent microorganisms.

    PubMed

    Fischer, Klaus; Majewsky, Marius

    2014-08-01

    Municipal wastewaters contain a multitude of organic trace pollutants. Often, their biodegradability by activated sludge microorganisms is decisive for their elimination during wastewater treatment. Since the amounts of micropollutants seem too low to serve as growth substrate, cometabolism is supposed to be the dominating biodegradation process. Nevertheless, as many biodegradation studies were performed without the intention to discriminate between metabolic and cometabolic processes, the specific contribution of the latter to substance transformations is often not clarified. This minireview summarizes current knowledge about the cometabolic degradation of organic trace pollutants by activated sludge and sludge-inherent microorganisms. Due to their relevance for communal wastewater contamination, the focus is laid on pharmaceuticals, personal care products, antibiotics, estrogens, and nonylphenols. Wherever possible, reference is made to the molecular process level, i.e., cometabolic pathways, involved enzymes, and formed transformation products. Particular cometabolic capabilities of different activated sludge consortia and various microbial species are highlighted. Process conditions favoring cometabolic activities are emphasized. Finally, knowledge gaps are identified, and research perspectives are outlined. PMID:24866947

  6. Free-energy landscape of mechanically unfolded model proteins: Extended Jarzinsky versus inherent structure reconstruction

    NASA Astrophysics Data System (ADS)

    Luccioli, Stefano; Imparato, Alberto; Torcini, Alessandro

    2008-09-01

    The equilibrium free-energy landscape of off-lattice model heteropolymers as a function of an internal coordinate, namely the end-to-end distance, is reconstructed from out-of-equilibrium steered molecular dynamics data. This task is accomplished via two independent methods: By employing an extended version of the Jarzynski equality and the inherent structure formalism. A comparison of the free energies estimated with these two schemes with equilibrium results obtained via the umbrella sampling technique reveals a good quantitative agreement among all the approaches in a range of temperatures around the “folding transition” for the two examined sequences. In particular, for the sequence with good foldability properties, the mechanically induced structural transitions can be related to thermodynamical aspects of folding. Moreover, for the same sequence the knowledge of the landscape profile allows for a good estimation of the lifetimes of the native configuration for temperatures ranging from the folding to the collapse temperature. For the random sequence, mechanical and thermal unfolding appear to follow different paths along the landscape.

  7. Optical closure in marine waters from in situ inherent optical property measurements.

    PubMed

    Lefering, Ina; Bengil, Fethi; Trees, Charles; Röttgers, Rüdiger; Bowers, David; Nimmo-Smith, Alex; Schwarz, Jill; McKee, David

    2016-06-27

    Optical closure using radiative transfer simulations can be used to determine the consistency of in situ measurements of inherent optical properties (IOPs) and radiometry. Three scattering corrections are applied to in situ absorption and attenuation profile data for a range of coastal and oceanic waters, but are found to have only very limited impact on subsequent closure attempts for these stations. Best-fit regressions on log-transformed measured and modelled downwards irradiance, Ed, and upwards radiance, Lu, profiles have median slopes between 0.92 - 1.24, revealing a tendency to underestimate Ed and Lu with depth. This is only partly explained by non-inclusion of fluorescence emission from CDOM and chlorophyll in the simulations. There are several stations where multiple volume scattering function related data processing steps perform poorly which suggests the potential existence of unresolved features in the modelling of the angular distribution of scattered photons. General optical closure therefore remains problematic, even though there are many cases in the data set where the match between measured and modelled radiometric data is within 25% RMS%E. These results are significant for applications that rely on optical closure e.g. assimilating ocean colour data into coupled physical-ecosystem models. PMID:27410565

  8. Temporal and among-site variability of inherent water use efficiency at the ecosystem level

    NASA Astrophysics Data System (ADS)

    Beer, C.; Ciais, P.; Reichstein, M.; Baldocchi, D.; Law, B. E.; Papale, D.; Soussana, J.-F.; Ammann, C.; Buchmann, N.; Frank, D.; Gianelle, D.; Janssens, I. A.; Knohl, A.; KöStner, B.; Moors, E.; Roupsard, O.; Verbeeck, H.; Vesala, T.; Williams, C. A.; Wohlfahrt, G.

    2009-06-01

    Half-hourly measurements of the net exchanges of carbon dioxide and water vapor between terrestrial ecosystems and the atmosphere provide estimates of gross primary production (GPP) and evapotranspiration (ET) at the ecosystem level and on daily to annual timescales. The ratio of these quantities represents ecosystem water use efficiency. Its multiplication with mean daylight vapor pressure deficit (VPD) leads to a quantity which we call "inherent water use efficiency" (IWUE*). The dependence of IWUE* on environmental conditions indicates possible adaptive adjustment of ecosystem physiology in response to a changing environment. IWUE* is analyzed for 43 sites across a range of plant functional types and climatic conditions. IWUE* increases during short-term moderate drought conditions. Mean annual IWUE* varied by a factor of 3 among all sites. This is partly explained by soil moisture at field capacity, particularly in deciduous broad-leaved forests. Canopy light interception sets the upper limits to canopy photosynthesis, and explains half the variance in annual IWUE* among herbaceous ecosystems and evergreen needle-leaved forests. Knowledge of IWUE* offers valuable improvement to the representation of carbon and water coupling in ecosystem process models.

  9. An analytic framework for developing inherently-manufacturable pop-up laminate devices

    NASA Astrophysics Data System (ADS)

    Aukes, Daniel M.; Goldberg, Benjamin; Cutkosky, Mark R.; Wood, Robert J.

    2014-09-01

    Spurred by advances in manufacturing technologies developed around layered manufacturing technologies such as PC-MEMS, SCM, and printable robotics, we propose a new analytic framework for capturing the geometry of folded composite laminate devices and the mechanical processes used to manufacture them. These processes can be represented by combining a small set of geometric operations which are general enough to encompass many different manufacturing paradigms. Furthermore, such a formulation permits one to construct a variety of geometric tools which can be used to analyze common manufacturability concepts, such as tool access, part removability, and device support. In order to increase the speed of development, reduce the occurrence of manufacturing problems inherent with current design methods, and reduce the level of expertise required to develop new devices, the framework has been implemented in a new design tool called popupCAD, which is suited for the design and development of complex folded laminate devices. We conclude with a demonstration of utility of the tools by creating a folded leg mechanism.

  10. Mapping of Total Suspended Solid from Inherent Optical Properties using Optical Model

    NASA Astrophysics Data System (ADS)

    Syahreza, S.; Beh, B. C.; Lim, H. S.; MatJafri, M. Z.; Abdullah, K.

    2011-03-01

    Environmental monitoring through the method of traditional ship sampling is time consuming and requires a high survey cost. An investigation has been conducted to test the feasibility of using OceanSat-2 for estimating Total Suspended Solid (TSS) in the coastal waters of Penang Island, Malaysia. The proposed algorithm is based on the reflectance model that is a function of the inherent optical properties of water, which can be related to its constituent's concentrations. Water samples were collected simultaneously with the satellite image acquisition and later analyzed in the laboratory. Water sample's locations were determined by using a handheld GPS. A simple atmospheric correction, namely darkest pixel technique was performed in this study. The pixel with the lowest value for each band was selected as the darkest pixel. The digital numbers for each band corresponding to the sea-truth locations were extracted and then converted into radiance values and reflectance values. The accuracies of algorithms was also investigated based on the observations of correlation coefficient (R) and root-mean-square deviations (RMS) with the sea-truth data. This algorithm was then used to map the TSS concentration over Penang, Malaysia. This study indicates that TSS mapping can be carried out using remote sensing technique of the satellite digital photography system over Penang, Malaysia.

  11. Computability, Gödel's incompleteness theorem, and an inherent limit on the predictability of evolution

    PubMed Central

    Day, Troy

    2012-01-01

    The process of evolutionary diversification unfolds in a vast genotypic space of potential outcomes. During the past century, there have been remarkable advances in the development of theory for this diversification, and the theory's success rests, in part, on the scope of its applicability. A great deal of this theory focuses on a relatively small subset of the space of potential genotypes, chosen largely based on historical or contemporary patterns, and then predicts the evolutionary dynamics within this pre-defined set. To what extent can such an approach be pushed to a broader perspective that accounts for the potential open-endedness of evolutionary diversification? There have been a number of significant theoretical developments along these lines but the question of how far such theory can be pushed has not been addressed. Here a theorem is proven demonstrating that, because of the digital nature of inheritance, there are inherent limits on the kinds of questions that can be answered using such an approach. In particular, even in extremely simple evolutionary systems, a complete theory accounting for the potential open-endedness of evolution is unattainable unless evolution is progressive. The theorem is closely related to Gödel's incompleteness theorem, and to the halting problem from computability theory. PMID:21849390

  12. Enhancement of the inherent self-protection of the fast sodium reactor cores with oxide fuel

    SciTech Connect

    Eliseev, V.A.; Malisheva, I.V.; Matveev, V.I.; Egorov, A.V.; Maslov, P.A.

    2013-07-01

    With the development and research into the generation IV fast sodium reactors, great attention is paid to the enhancement of the core inherent self-protection characteristics. One of the problems dealt here is connected with the reduction of the reactivity margin so that the control rods running should not result in the core overheating and melting. In this paper we consider the possibilities of improving the core of BN-1200 with oxide fuel by a known method of introducing an axial fertile layer into the core. But unlike earlier studies this paper looks at the possibility of using such a layer not only for improving breeding, but also for reducing sodium void reactivity effect (SVRE). This proposed improvement of the BN-1200 core does not solve the problem of strong interference in control and protection system (CPS) rods of BN-1200, but they reduce significantly the reactivity margin for burn-up compensation. This helps compensate all the reactivity balances in the improved core configurations without violating constraints on SVRE value.

  13. Anatomical accuracy of brain connections derived from diffusion MRI tractography is inherently limited.

    PubMed

    Thomas, Cibu; Ye, Frank Q; Irfanoglu, M Okan; Modi, Pooja; Saleem, Kadharbatcha S; Leopold, David A; Pierpaoli, Carlo

    2014-11-18

    Tractography based on diffusion-weighted MRI (DWI) is widely used for mapping the structural connections of the human brain. Its accuracy is known to be limited by technical factors affecting in vivo data acquisition, such as noise, artifacts, and data undersampling resulting from scan time constraints. It generally is assumed that improvements in data quality and implementation of sophisticated tractography methods will lead to increasingly accurate maps of human anatomical connections. However, assessing the anatomical accuracy of DWI tractography is difficult because of the lack of independent knowledge of the true anatomical connections in humans. Here we investigate the future prospects of DWI-based connectional imaging by applying advanced tractography methods to an ex vivo DWI dataset of the macaque brain. The results of different tractography methods were compared with maps of known axonal projections from previous tracer studies in the macaque. Despite the exceptional quality of the DWI data, none of the methods demonstrated high anatomical accuracy. The methods that showed the highest sensitivity showed the lowest specificity, and vice versa. Additionally, anatomical accuracy was highly dependent upon parameters of the tractography algorithm, with different optimal values for mapping different pathways. These results suggest that there is an inherent limitation in determining long-range anatomical projections based on voxel-averaged estimates of local fiber orientation obtained from DWI data that is unlikely to be overcome by improvements in data acquisition and analysis alone. PMID:25368179

  14. Rapid synthesis of inherently robust and stable superhydrophobic carbon soot coatings

    NASA Astrophysics Data System (ADS)

    Esmeryan, Karekin D.; Castano, Carlos E.; Bressler, Ashton H.; Abolghasemibizaki, Mehran; Mohammadi, Reza

    2016-04-01

    The fabrication of superhydrophobic coatings using a candle flame or rapeseed oil has become very attractive as a novel approach for synthesis of water repellent surfaces. Here, we report an improved, simplified and time-efficient method for the preparation of robust superhydrophobic carbon soot that does not require any additional stabilizers or chemical treatment. The soot's inherent stabilization is achieved using a specially-designed cone-shaped aluminum chimney, mounted over an ignited paper-based wick immersed in a rapeseed oil. Such configuration decreases the level of oxygen during the process of combustion; altering the ratio of chemical bonds in the soot. As a result, the fractal-like network of the carbon nanoparticles is converted into dense and fused carbon chains, rigidly coupled to the substrate surface. The modified carbon coating shows thermal sustainability and retains superhydrophobicity up to ∼300 °C. Furthermore, it demonstrates a low contact angle hysteresis of 0.7-1.2° accompanied by enhanced surface adhesion and mechanical durability under random water flows. In addition, the soot's deposition rate of ∼1.5 μm/s reduces the exposure time of the substrate to heat and consequently minimizes the thermal effects, allowing the creation of superhydrophobic coatings on materials with low thermal stability (e.g. wood or polyethylene).

  15. Inherent Structure-Based Multiview Learning With Multitemplate Feature Representation for Alzheimer's Disease Diagnosis.

    PubMed

    Liu, Mingxia; Zhang, Daoqiang; Adeli, Ehsan; Shen, Dinggang

    2016-07-01

    Multitemplate-based brain morphometric pattern analysis using magnetic resonance imaging has been recently proposed for automatic diagnosis of Alzheimer's disease (AD) and its prodromal stage (i.e., mild cognitive impairment or MCI). In such methods, multiview morphological patterns generated from multiple templates are used as feature representation for brain images. However, existing multitemplate-based methods often simply assume that each class is represented by a specific type of data distribution (i.e., a single cluster), while in reality, the underlying data distribution is actually not preknown. In this paper, we propose an inherent structure-based multiview leaning method using multiple templates for AD/MCI classification. Specifically, we first extract multiview feature representations for subjects using multiple selected templates and then cluster subjects within a specific class into several subclasses (i.e., clusters) in each view space. Then, we encode those subclasses with unique codes by considering both their original class information and their own distribution information, followed by a multitask feature selection model. Finally, we learn an ensemble of view-specific support vector machine classifiers based on their, respectively, selected features in each view and fuse their results to draw the final decision. Experimental results on the Alzheimer's Disease Neuroimaging Initiative database demonstrate that our method achieves promising results for AD/MCI classification, compared to the state-of-the-art multitemplate-based methods. PMID:26540666

  16. Inherent Dynamics of the Acid-Sensing Ion Channel 1 Correlates with the Gating Mechanism

    PubMed Central

    Li, Wei-Guang; Yu, Fang; Cao, Hui; Xu, Tian-Le; Jiang, Hualiang

    2009-01-01

    The acid-sensing ion channel 1 (ASIC1) is a key receptor for extracellular protons. Although numerous structural and functional studies have been performed on this channel, the structural dynamics underlying the gating mechanism remains unknown. We used normal mode analysis, mutagenesis, and electrophysiological methods to explore the relationship between the inherent dynamics of ASIC1 and its gating mechanism. Here we show that a series of collective motions among the domains and subdomains of ASIC1 correlate with its acid-sensing function. The normal mode analysis result reveals that the intrinsic rotation of the extracellular domain and the collective motions between the thumb and finger induced by proton binding drive the receptor to experience a deformation from the extracellular domain to the transmembrane domain, triggering the channel pore to undergo “twist-to-open” motions. The movements in the transmembrane domain indicate that the likely position of the channel gate is around Leu440. These motion modes are compatible with a wide body of our complementary mutations and electrophysiological data. This study provides the dynamic fundamentals of ASIC1 gating. PMID:19597538

  17. Improved Accuracy of the Inherent Shrinkage Method for Fast and More Reliable Welding Distortion Calculations

    NASA Astrophysics Data System (ADS)

    Mendizabal, A.; González-Díaz, J. B.; San Sebastián, M.; Echeverría, A.

    2016-05-01

    This paper describes the implementation of a simple strategy adopted for the inherent shrinkage method (ISM) to predict welding-induced distortion. This strategy not only makes it possible for the ISM to reach accuracy levels similar to the detailed transient analysis method (considered the most reliable technique for calculating welding distortion) but also significantly reduces the time required for these types of calculations. This strategy is based on the sequential activation of welding blocks to account for welding direction and transient movement of the heat source. As a result, a significant improvement in distortion prediction is achieved. This is demonstrated by experimentally measuring and numerically analyzing distortions in two case studies: a vane segment subassembly of an aero-engine, represented with 3D-solid elements, and a car body component, represented with 3D-shell elements. The proposed strategy proves to be a good alternative for quickly estimating the correct behaviors of large welded components and may have important practical applications in the manufacturing industry.

  18. Mixed variational potentials and inherent symmetries of the Cahn–Hilliard theory of diffusive phase separation

    PubMed Central

    Miehe, C.; Hildebrand, F. E.; Böger, L.

    2014-01-01

    This work shows that the Cahn–Hilliard theory of diffusive phase separation is related to an intrinsic mixed variational principle that determines the rate of concentration and the chemical potential. The principle characterizes a canonically compact model structure, where the two balances involved for the species content and microforce appear as the Euler equations of a variational statement. The existence of the variational principle underlines an inherent symmetry in the two-field representation of the Cahn–Hilliard theory. This can be exploited in the numerical implementation by the construction of time- and space-discrete incremental potentials, which fully determine the update problems of typical time-stepping procedures. The mixed variational principles provide the most fundamental approach to the finite-element solution of the Cahn–Hilliard equation based on low-order basis functions, leading to monolithic symmetric algebraic systems of iterative update procedures based on a linearization of the nonlinear problem. They induce in a natural format the choice of symmetric solvers for Newton-type iterative updates, providing a speed-up and reduction of data storage when compared with non-symmetric implementations. In this sense, the potentials developed are believed to be fundamental ingredients to a deeper understanding of the Cahn–Hilliard theory. PMID:24711722

  19. Bayesian estimation inherent in a Mexican-hat-type neural network

    NASA Astrophysics Data System (ADS)

    Takiyama, Ken

    2016-05-01

    Brain functions, such as perception, motor control and learning, and decision making, have been explained based on a Bayesian framework, i.e., to decrease the effects of noise inherent in the human nervous system or external environment, our brain integrates sensory and a priori information in a Bayesian optimal manner. However, it remains unclear how Bayesian computations are implemented in the brain. Herein, I address this issue by analyzing a Mexican-hat-type neural network, which was used as a model of the visual cortex, motor cortex, and prefrontal cortex. I analytically demonstrate that the dynamics of an order parameter in the model corresponds exactly to a variational inference of a linear Gaussian state-space model, a Bayesian estimation, when the strength of recurrent synaptic connectivity is appropriately stronger than that of an external stimulus, a plausible condition in the brain. This exact correspondence can reveal the relationship between the parameters in the Bayesian estimation and those in the neural network, providing insight for understanding brain functions.

  20. Inherent Tracers for Carbon Capture and Storage in Sedimentary Formations: Composition and Applications.

    PubMed

    Flude, Stephanie; Johnson, Gareth; Gilfillan, Stuart M V; Haszeldine, R Stuart

    2016-08-01

    Inherent tracers-the "natural" isotopic and trace gas composition of captured CO2 streams-are potentially powerful tracers for use in CCS technology. This review outlines for the first time the expected carbon isotope and noble gas compositions of captured CO2 streams from a range of feedstocks, CO2-generating processes, and carbon capture techniques. The C-isotope composition of captured CO2 will be most strongly controlled by the feedstock, but significant isotope fractionation is possible during capture; noble gas concentrations will be controlled by the capture technique employed. Comparison with likely baseline data suggests that CO2 generated from fossil fuel feedstocks will often have δ(13)C distinguishable from storage reservoir CO2. Noble gases in amine-captured CO2 streams are likely to be low concentration, with isotopic ratios dependent on the feedstock, but CO2 captured from oxyfuel plants may be strongly enriched in Kr and Xe which are potentially valuable subsurface tracers. CO2 streams derived from fossil fuels will have noble gas isotope ratios reflecting a radiogenic component that will be difficult to distinguish in the storage reservoir, but inheritance of radiogenic components will provide an easily recognizable signature in the case of any unplanned migration into shallow aquifers or to the surface. PMID:27379462

  1. Aire Expression Is Inherent to Most Medullary Thymic Epithelial Cells during Their Differentiation Program.

    PubMed

    Kawano, Hiroshi; Nishijima, Hitoshi; Morimoto, Junko; Hirota, Fumiko; Morita, Ryoko; Mouri, Yasuhiro; Nishioka, Yasuhiko; Matsumoto, Mitsuru

    2015-12-01

    Aire in medullary thymic epithelial cells (mTECs) plays an important role in the establishment of self-tolerance. Because Aire(+) mTECs appear to be a limited subset, they may constitute a unique lineage(s) among mTECs. An alternative possibility is that all mTECs are committed to express Aire in principle, but Aire expression by individual mTECs is conditional. To investigate this issue, we established a novel Aire reporter strain in which endogenous Aire is replaced by the human AIRE-GFP-Flag tag (Aire/hAGF-knockin) fusion gene. The hAGF reporter protein was produced and retained very efficiently within mTECs as authentic Aire nuclear dot protein. Remarkably, snapshot analysis revealed that mTECs expressing hAGF accounted for >95% of mature mTECs, suggesting that Aire expression does not represent a particular mTEC lineage(s). We confirmed this by generating Aire/diphtheria toxin receptor-knockin mice in which long-term ablation of Aire(+) mTECs by diphtheria toxin treatment resulted in the loss of most mature mTECs beyond the proportion of those apparently expressing Aire. These results suggest that Aire expression is inherent to all mTECs but may occur at particular stage(s) and/or cellular states during their differentiation, thus accounting for the broad impact of Aire on the promiscuous gene expression of mTECs. PMID:26503950

  2. Retrieving Marine Inherent Optical Properties from Satellites Using Temperature and Salinity-dependent Backscattering by Seawater

    NASA Technical Reports Server (NTRS)

    Werdell, Paul J.; Franz, Bryan Alden; Lefler, Jason Travis; Robinson, Wayne D.; Boss, Emmanuel

    2013-01-01

    Time-series of marine inherent optical properties (IOPs) from ocean color satellite instruments provide valuable data records for studying long-term time changes in ocean ecosystems. Semi-analytical algorithms (SAAs) provide a common method for estimating IOPs from radiometric measurements of the marine light field. Most SAAs assign constant spectral values for seawater absorption and backscattering, assume spectral shape functions of the remaining constituent absorption and scattering components (e.g., phytoplankton, non-algal particles, and colored dissolved organic matter), and retrieve the magnitudes of each remaining constituent required to match the spectral distribution of measured radiances. Here, we explore the use of temperature- and salinity-dependent values for seawater backscattering in lieu of the constant spectrum currently employed by most SAAs. Our results suggest that use of temperature- and salinity-dependent seawater spectra elevate the SAA-derived particle backscattering, reduce the non-algal particles plus colored dissolved organic matter absorption, and leave the derived absorption by phytoplankton unchanged.

  3. Generalized Ocean Color Inversion Model for Retrieving Marine Inherent Optical Properties

    NASA Technical Reports Server (NTRS)

    Werdell, P. Jeremy; Franz, Bryan A.; Bailey, Sean W.; Feldman, Gene C.; Boss, Emmanuel; Brando, Vittorio E.; Dowell, Mark; Hirata, Takafumi; Lavender, Samantha J.; Lee, ZhongPing; Loisel, Hubert; Maritorena, Stephane; Melin, Frederic; Moore, Timothy S.; Smyth, TImothy J.; Antoine, David; Devred, Emmanuel; Fantond'Andon, Odile Hembise; Mangin, Antoine

    2013-01-01

    Ocean color measured from satellites provides daily, global estimates of marine inherent optical properties (IOPs). Semi-analytical algorithms (SAAs) provide one mechanism for inverting the color of the water observed by the satellite into IOPs. While numerous SAAs exist, most are similarly constructed and few are appropriately parameterized for all water masses for all seasons. To initiate community-wide discussion of these limitations, NASA organized two workshops that deconstructed SAAs to identify similarities and uniqueness and to progress toward consensus on a unified SAA. This effort resulted in the development of the generalized IOP (GIOP) model software that allows for the construction of different SAAs at runtime by selection from an assortment of model parameterizations. As such, GIOP permits isolation and evaluation of specific modeling assumptions, construction of SAAs, development of regionally tuned SAAs, and execution of ensemble inversion modeling. Working groups associated with the workshops proposed a preliminary default configuration for GIOP (GIOP-DC), with alternative model parameterizations and features defined for subsequent evaluation. In this paper, we: (1) describe the theoretical basis of GIOP; (2) present GIOP-DC and verify its comparable performance to other popular SAAs using both in situ and synthetic data sets; and, (3) quantify the sensitivities of their output to their parameterization. We use the latter to develop a hierarchical sensitivity of SAAs to various model parameterizations, to identify components of SAAs that merit focus in future research, and to provide material for discussion on algorithm uncertainties and future ensemble applications.

  4. Recalcitrance: An Inherent Relative Attribute of Plant Litter Describing Its Potential Decomposability

    NASA Astrophysics Data System (ADS)

    Cotrufo, M. F.; Fulton-Smith, S.; Haddix, M. L.; Horton, A. J.; Soong, J.

    2014-12-01

    While the term "litter quality" is vague and can always be associated to a specific litter property (e.g., C:N, %lignin, decay rate), and thus should be replaced with the term that describes that property (e.g., stoichiometry, C-chemistry, recalcitrance), we defend the use of the term "recalcitrance" to describe the potential decomposability of litter, or its components. Recalcitrance can be quantified in laboratory incubations, by measuring the rate of production of CO2 from litter, under optimal environmental conditions. "Recalcitrance" is an inherent relative attribute of litter resulting from the synergistic interactions of several specific physic-chemical properties (e.g., stoichiometry, chemistry, energetic, physical structure) of that litter which in absence of environmental constraints (i.e., microbial limitation, physical aggregation, mineral-bonding) determine its potential rate of CO2 production. Because these environmental constraints often cannot be excluded in studies of soil organic matter (SOM), the term "recalcitrance" is not appropriate for SOM, and "persistence" is preferred. Recalcitrance is, of course, relative and requests a time scale of reference, since any litter eventually decomposes. We will illustrate this rational with examples from our latest laboratory incubations using: 1) a variety of plant litter types, 2) litter with differential isotopic enrichment of the metabolic and structural components, 3) soils containing isotopic enriched litter-derived organic matter.

  5. Improved Accuracy of the Inherent Shrinkage Method for Fast and More Reliable Welding Distortion Calculations

    NASA Astrophysics Data System (ADS)

    Mendizabal, A.; González-Díaz, J. B.; San Sebastián, M.; Echeverría, A.

    2016-07-01

    This paper describes the implementation of a simple strategy adopted for the inherent shrinkage method (ISM) to predict welding-induced distortion. This strategy not only makes it possible for the ISM to reach accuracy levels similar to the detailed transient analysis method (considered the most reliable technique for calculating welding distortion) but also significantly reduces the time required for these types of calculations. This strategy is based on the sequential activation of welding blocks to account for welding direction and transient movement of the heat source. As a result, a significant improvement in distortion prediction is achieved. This is demonstrated by experimentally measuring and numerically analyzing distortions in two case studies: a vane segment subassembly of an aero-engine, represented with 3D-solid elements, and a car body component, represented with 3D-shell elements. The proposed strategy proves to be a good alternative for quickly estimating the correct behaviors of large welded components and may have important practical applications in the manufacturing industry.

  6. NASA's aviation safety research and technology program

    NASA Technical Reports Server (NTRS)

    Fichtl, G. H.

    1977-01-01

    Aviation safety is challenged by the practical necessity of compromising inherent factors of design, environment, and operation. If accidents are to be avoided these factors must be controlled to a degree not often required by other transport modes. The operational problems which challenge safety seem to occur most often in the interfaces within and between the design, the environment, and operations where mismatches occur due to ignorance or lack of sufficient understanding of these interactions. Under this report the following topics are summarized: (1) The nature of operating problems, (2) NASA aviation safety research, (3) clear air turbulence characterization and prediction, (4) CAT detection, (5) Measurement of Atmospheric Turbulence (MAT) Program, (6) Lightning, (7) Thunderstorm gust fronts, (8) Aircraft ground operating problems, (9) Aircraft fire technology, (10) Crashworthiness research, (11) Aircraft wake vortex hazard research, and (12) Aviation safety reporting system.

  7. Systems pharmacology augments drug safety surveillance.

    PubMed

    Lorberbaum, T; Nasir, M; Keiser, M J; Vilar, S; Hripcsak, G; Tatonetti, N P

    2015-02-01

    Small molecule drugs are the foundation of modern medical practice, yet their use is limited by the onset of unexpected and severe adverse events (AEs). Regulatory agencies rely on postmarketing surveillance to monitor safety once drugs are approved for clinical use. Despite advances in pharmacovigilance methods that address issues of confounding bias, clinical data of AEs are inherently noisy. Systems pharmacology-the integration of systems biology and chemical genomics-can illuminate drug mechanisms of action. We hypothesize that these data can improve drug safety surveillance by highlighting drugs with a mechanistic connection to the target phenotype (enriching true positives) and filtering those that do not (depleting false positives). We present an algorithm, the modular assembly of drug safety subnetworks (MADSS), to combine systems pharmacology and pharmacovigilance data and significantly improve drug safety monitoring for four clinically relevant adverse drug reactions. PMID:25670520

  8. EHS Open House: Learning Lab and Life Safety | Poster

    Cancer.gov

    Attendees of the Environment, Health, and Safety Program’s (EHS’) Open House had a chance to learn self-defense techniques, as well as visit with vendors demonstrating the latest trends in laboratory safety. “Working with sharps in labs is inherently dangerous, so EHS proactively focused on featuring equipment that would promote safer techniques,” said Siobhan Tierney, program manager, EHS.

  9. System safety education focused on flight safety

    NASA Technical Reports Server (NTRS)

    Holt, E.

    1971-01-01

    The measures necessary for achieving higher levels of system safety are analyzed with an eye toward maintaining the combat capability of the Air Force. Several education courses were provided for personnel involved in safety management. Data include: (1) Flight Safety Officer Course, (2) Advanced Safety Program Management, (3) Fundamentals of System Safety, and (4) Quantitative Methods of Safety Analysis.

  10. Predicting welding distortion in a panel structure with longitudinal stiffeners using inherent deformations obtained by inverse analysis method.

    PubMed

    Liang, Wei; Murakawa, Hidekazu

    2014-01-01

    Welding-induced deformation not only negatively affects dimension accuracy but also degrades the performance of product. If welding deformation can be accurately predicted beforehand, the predictions will be helpful for finding effective methods to improve manufacturing accuracy. Till now, there are two kinds of finite element method (FEM) which can be used to simulate welding deformation. One is the thermal elastic plastic FEM and the other is elastic FEM based on inherent strain theory. The former only can be used to calculate welding deformation for small or medium scale welded structures due to the limitation of computing speed. On the other hand, the latter is an effective method to estimate the total welding distortion for large and complex welded structures even though it neglects the detailed welding process. When the elastic FEM is used to calculate the welding-induced deformation for a large structure, the inherent deformations in each typical joint should be obtained beforehand. In this paper, a new method based on inverse analysis was proposed to obtain the inherent deformations for weld joints. Through introducing the inherent deformations obtained by the proposed method into the elastic FEM based on inherent strain theory, we predicted the welding deformation of a panel structure with two longitudinal stiffeners. In addition, experiments were carried out to verify the simulation results. PMID:25276856

  11. Influence of the key parameters of suspended structures on the inherent frequency of oil and gas pipelines

    NASA Astrophysics Data System (ADS)

    Tao, S. Y.; Liu, Q. Y.; Wang, G. R.; Jiang, J. C.

    2015-10-01

    Inherent frequency is an important parameter that reflects the dynamic stability of fluid-conveying pipelines. In engineering applications, the inherent frequency of pipelines is usually increased to improve their dynamic stability. The flow velocity and pressure of oil and gas pipelines cannot be altered freely. Among all of the parameters that affect the inherent frequency of suspended pipelines, the flexural stiffness of the stiffening girder, the tensile force of the cable system, and the pipe-axial precompression force are the most important. Revealing the influence laws of these three parameters could provide theoretical support for engineering designs. In this paper, a suspended crossing pipeline project was simplified as a Hetenyi's elastic foundation model. The flexural stiffness of the stiffening girder and the tensile force of the cable system were simplified as the foundation parameters G and K, respectively. The influence regularities of G, K, and the pipe-axial precompression force T on the pipeline inherent frequency were analyzed. According to the numerical simulation results, the ranks of these three parameters in descending order of importance were G, T, and K. During construction, G should be increased as much as possible. If the inherent frequency needs to be improved while pipelines have already been built up, it should be firstly considered to increase T, to values higher than zero if possible. On this basis, the further improvement of K could achieve a better result.

  12. Predicting Welding Distortion in a Panel Structure with Longitudinal Stiffeners Using Inherent Deformations Obtained by Inverse Analysis Method

    PubMed Central

    Liang, Wei; Murakawa, Hidekazu

    2014-01-01

    Welding-induced deformation not only negatively affects dimension accuracy but also degrades the performance of product. If welding deformation can be accurately predicted beforehand, the predictions will be helpful for finding effective methods to improve manufacturing accuracy. Till now, there are two kinds of finite element method (FEM) which can be used to simulate welding deformation. One is the thermal elastic plastic FEM and the other is elastic FEM based on inherent strain theory. The former only can be used to calculate welding deformation for small or medium scale welded structures due to the limitation of computing speed. On the other hand, the latter is an effective method to estimate the total welding distortion for large and complex welded structures even though it neglects the detailed welding process. When the elastic FEM is used to calculate the welding-induced deformation for a large structure, the inherent deformations in each typical joint should be obtained beforehand. In this paper, a new method based on inverse analysis was proposed to obtain the inherent deformations for weld joints. Through introducing the inherent deformations obtained by the proposed method into the elastic FEM based on inherent strain theory, we predicted the welding deformation of a panel structure with two longitudinal stiffeners. In addition, experiments were carried out to verify the simulation results. PMID:25276856

  13. Remote Sensing Reflectance and Inherent Optical Properties in the Mid-mesohaline Chesapeake Bay

    NASA Technical Reports Server (NTRS)

    Tzortziou, Maria; Subramaniam, Ajit; Herman, Jay R.; Gallegos, Charles L.; Neal, Patrick J.; Harding, Lawrence W., Jr.

    2006-01-01

    We used an extensive set of bio-optical data and radiative transfer (RT) model simulations of radiation fields to investigate relationships between inherent optical properties and remotely sensed quantities in the optically complex, mid-mesohaline Chesapeake Bay waters. Field observations showed that the chlorophyll algorithms used by the MODIS (MODerate resolution Imaging Spectroradiometer) ocean color sensor (i.e. Chlor_a, chlor_MODIS, chlor_a_3 products) do not perform accurately in these Case 2 waters. This is because, when applied to waters with high concentrations of chlorophyll, all MODIS algorithms are based on empirical relationships between chlorophyll concentration and blue-green wavelength remote sensing reflectance (Rrs) ratios that do not account for the typically strong blue-wavelength absorption by non-covarying, dissolved and non-algal particulate components. Stronger correlation was observed between chlorophyll concentration and Rrs ratios in the red (i.e. Rrs(677)/Rrs(554)) where dissolved and non-algal particulate absorption become exponentially smaller. Regionally-specific algorithms that are based on the phytoplankton optical properties in the red wavelength region provide a better basis for satellite monitoring of phytoplankton blooms in these Case 2 waters. Good optical closure was obtained between independently measured Rrs spectra and the optical properties of backscattering, b(sub b), and absorption, a, over the wide range of in-water conditions observed in the Chesapeake Bay. Observed variability in the quantity f/Q (proportionality factor in the relationship between Rrs and the water inherent optical properties ratio b(sub b)/(a+b(sub b)) was consistent with RT model calculations for the specific measurement geometry and water bio-optical characteristics. Data and model results showed that f/Q values in these Case 2 coastal waters are not considerably different from those estimated in previous studies for Case 1 waters. Variation in

  14. Improving Coastal Ocean Color Validation Capabilities through Application of Inherent Optical Properties (IOPs)

    NASA Technical Reports Server (NTRS)

    Mannino, Antonio

    2008-01-01

    Understanding how the different components of seawater alter the path of incident sunlight through scattering and absorption is essential to using remotely sensed ocean color observations effectively. This is particularly apropos in coastal waters where the different optically significant components (phytoplankton, detrital material, inorganic minerals, etc.) vary widely in concentration, often independently from one another. Inherent Optical Properties (IOPs) form the link between these biogeochemical constituents and the Apparent Optical Properties (AOPs). understanding this interrelationship is at the heart of successfully carrying out inversions of satellite-measured radiance to biogeochemical properties. While sufficient covariation of seawater constituents in case I waters typically allows empirical algorithms connecting AOPs and biogeochemical parameters to behave well, these empirical algorithms normally do not hold for case I1 regimes (Carder et al. 2003). Validation in the context of ocean color remote sensing refers to in-situ measurements used to verify or characterize algorithm products or any assumption used as input to an algorithm. In this project, validation capabilities are considered those measurement capabilities, techniques, methods, models, etc. that allow effective validation. Enhancing current validation capabilities by incorporating state-of-the-art IOP measurements and optical models is the purpose of this work. Involved in this pursuit is improving core IOP measurement capabilities (spectral, angular, spatio-temporal resolutions), improving our understanding of the behavior of analytical AOP-IOP approximations in complex coastal waters, and improving the spatial and temporal resolution of biogeochemical data for validation by applying biogeochemical-IOP inversion models so that these parameters can be computed from real-time IOP sensors with high sampling rates. Research cruises supported by this project provides for collection and

  15. Inherent and apparent optical properties of the complex estuarine waters of Tampa Bay: What controls light?

    NASA Astrophysics Data System (ADS)

    Le, Chengfeng; Hu, Chuanmin; English, David; Cannizzaro, Jennifer; Chen, Zhiqiang; Kovach, Charles; Anastasiou, Christopher J.; Zhao, Jun; Carder, Kendall L.

    2013-01-01

    Inherent and apparent optical properties (IOPs and AOPs) of Tampa Bay (Florida, USA) were measured during fourteen cruises between February 1998 and October 2010 to understand how these properties relate to one another and what controls light absorption and diffuse attenuation in this moderately sized (˜1000 km2), shallow estuary (average depth ˜4 m). The IOPs and AOPs included: 1) absorption coefficients of three optically significant constituents: phytoplankton pigments, detrital particles, and colored dissolved organic matter (CDOM); 2) particulate backscattering coefficients; 3) chlorophyll-a concentrations; 4) above-water remote sensing reflectance; 5) downwelling diffuse attenuation coefficients (Kd) at eight wavelengths and photosynthetically active radiation (PAR). Results showed substantial variability in all IOPs and AOPs in both space and time, with most IOPs spanning more than two orders of magnitude and showing strong co-variations. Of all four bay segments, Old Tampa Bay showed unique optical characteristics. During the wet season, the magnitude of blue-green-light absorption was dominated by CDOM, while during the dry season all three constituents contributed significantly. However, the variability in Kd (PAR, 490 nm, 555 nm) was driven mainly by the variability of detrital particles and phytoplankton as opposed to CDOM. This observation explained, at least to first order, why a nutrient reduction management strategy used by the Tampa Bay Estuary Program since the 1990s led to improved water clarity in most of Tampa Bay. The findings of this study provided the optical basis to fine tune existing or develop new algorithms to estimate the various optical water quality parameters from space.

  16. Modelling the inherent optical properties and estimating the constituents' concentrations in turbid and eutrophic waters

    NASA Astrophysics Data System (ADS)

    Gokul, Elamurugu Alias; Shanmugam, Palanisamy; Sundarabalan, Balasubramanian; Sahay, Arvind; Chauhan, Prakash

    2014-08-01

    Retrieval of the inherent optical properties and estimation of the constituents' concentrations from satellite ocean colour data in turbid and eutrophic waters are important as these products provide innovative opportunities for the study of biological and biogeochemical properties in such optically complex waters. This paper intends to develop models to retrieve absorption coefficients of phytoplankton, suspended sediments and coloured dissolved organic matter and describe vertical profiles of chlorophyll and suspended sediments from satellite ocean colour data. These models make use of the relationships between remote sensing reflectance ratios Rrs (555)/Rrs (443) and Rrs (620)/Rrs (490) versus aph (443) and aph (555), and acdom (443), and ad (443) to derive the model parameters. Validation with the in-situ data obtained from coastal waters around India and other regional waters (e.g., NASA bio-Optical Marine Algorithm Data-Set, NOMAD) shows that the new models are more accurate in terms of producing the spectral absorption coefficients (aph, ad, acdom across the entire visible wavelengths 400-700 nm) in a wide variety of waters. Further comparison with existing models shows advantage of the new models that have important implications for remote sensing of turbid coastal and eutrophic waters. The retrieved absorption coefficients of phytoplankton and suspended sediments (non-algal matter) are also found to relate better to chlorophyll and total suspended sediments. Taking advantages of this, we derive models to determine and describe the vertical profiles of chlorophyll and suspended sediment concentrations along the depth. The model parameters are derived empirically. These new parameterizations show potential in estimating the vertical profiles of chlorophyll and suspended sediments with good accuracy. These results suggest robustness and suitability of the new models for studying the ecologically important components of optically complex turbid and eutrophic

  17. Impact of calcification state on the inherent optical properties of Emiliania huxleyi coccoliths and coccolithophores

    NASA Astrophysics Data System (ADS)

    Bi, Lei; Yang, Ping

    2015-04-01

    Understanding the inherent optical properties (IOPs) of coccoliths and coccolithophores is important in oceanic radiative transfer simulations and remote sensing implementations. In this study, the invariant imbedding T-matrix method (II-TM) is employed to investigate the IOPs of coccoliths and coccolithophores. The Emiliania huxleyi (Ehux) coccolith and coccolithophore models are built based on observed biometric parameters including the eccentricity, the number of slits, and the rim width of detached coccoliths. The calcification state that specifies the amount of calcium of a single coccolith is critical in the determination of the size-volume/mass relationship (note, the volume/mass of coccoltihs at different calcification states are different although the diameters are the same). The present results show that the calcification state, namely, under-calcification, normal-calcification, or over-calcification, significantly influences the backscattering cross section and the phase matrix. Furthermore, the linear depolarization ratio of the light scattered by coccoliths is sensitive to the degree of calcification, and provides a potentially valuable parameter for interpreting oceanic remote sensing data. The phase function of an ensemble of randomly oriented coccolithophores has a similar pattern to that of individual coccoliths, but the forward scattering is dominant in the coccolithophores due to the large geometric cross sections. The linear depolarization ratio associated with coccolithophores is found to be larger than that for coccoliths as polarization is more sensitive to multiple scattering than the phase function. The simulated coccolithophore phase matrix numerical results are compared with laboratory measurements. For scattering angles larger than 100°, an increase of the phase function with respect to the scattering angle is confirmed based on the present coccolithophore model while the spherical approximation fails.

  18. The hype cycle in 3D displays: inherent limits of autostereoscopy

    NASA Astrophysics Data System (ADS)

    Grasnick, Armin

    2013-06-01

    Since a couple of years, a renaissance of 3dimensional cinema can be observed. Even though the stereoscopy was quite popular within the last 150 years, the 3d cinema has disappeared and re-established itself several times. The first boom in the late 19th century stagnated and vanished after a few years of success, the same happened again in 50's and 80's of the 20th century. With the commercial success of the 3d blockbuster "Avatar" in 2009, at the latest, it is obvious that the 3d cinema is having a comeback. How long will it last this time? There are already some signs of a declining interest in 3d movies, as the discrepancy between expectations and the results delivered becomes more evident. From the former hypes it is known: After an initial phase of curiosity (high expectations and excessive fault tolerance), a phase of frustration and saturation (critical analysis and subsequent disappointment) will follow. This phenomenon is known as "Hype Cycle" The everyday experienced evolution of technology has conditioned the consumers. The expectation "any technical improvement will preserve all previous properties" cannot be fulfilled with present 3d technologies. This is an inherent problem of stereoscopy and autostereoscopy: The presentation of an additional dimension caused concessions in relevant characteristics (i.e. resolution, brightness, frequency, viewing area) or leads to undesirable physical side effects (i.e. subjective discomfort, eye strain, spatial disorientation, feeling of nausea). It will be verified that the 3d apparatus (3d glasses or 3d display) is also the source for these restrictions and a reason for decreasing fascination. The limitations of present autostereoscopic technologies will be explained.

  19. Technical Note: Millimeter precision in ultrasound based patient positioning: Experimental quantification of inherent technical limitations

    SciTech Connect

    Ballhausen, Hendrik Hieber, Sheila; Li, Minglun; Belka, Claus; Reiner, Michael

    2014-08-15

    Purpose: To identify the relevant technical sources of error of a system based on three-dimensional ultrasound (3D US) for patient positioning in external beam radiotherapy. To quantify these sources of error in a controlled laboratory setting. To estimate the resulting end-to-end geometric precision of the intramodality protocol. Methods: Two identical free-hand 3D US systems at both the planning-CT and the treatment room were calibrated to the laboratory frame of reference. Every step of the calibration chain was repeated multiple times to estimate its contribution to overall systematic and random error. Optimal margins were computed given the identified and quantified systematic and random errors. Results: In descending order of magnitude, the identified and quantified sources of error were: alignment of calibration phantom to laser marks 0.78 mm, alignment of lasers in treatment vs planning room 0.51 mm, calibration and tracking of 3D US probe 0.49 mm, alignment of stereoscopic infrared camera to calibration phantom 0.03 mm. Under ideal laboratory conditions, these errors are expected to limit ultrasound-based positioning to an accuracy of 1.05 mm radially. Conclusions: The investigated 3D ultrasound system achieves an intramodal accuracy of about 1 mm radially in a controlled laboratory setting. The identified systematic and random errors require an optimal clinical tumor volume to planning target volume margin of about 3 mm. These inherent technical limitations do not prevent clinical use, including hypofractionation or stereotactic body radiation therapy.

  20. Evolution of stress-induced borehole breakout in inherently anisotropic rock: Insights from discrete element modeling

    NASA Astrophysics Data System (ADS)

    Duan, K.; Kwok, C. Y.

    2016-04-01

    The aim of this study is to better understand the mechanisms controlling the initiation, propagation, and ultimate pattern of borehole breakouts in shale formation when drilled parallel with and perpendicular to beddings. A two-dimensional discrete element model is constructed to explicitly represent the microstructure of inherently anisotropic rocks by inserting a series of individual smooth joints into an assembly of bonded rigid discs. Both isotropic and anisotropic hollow square-shaped samples are generated to represent the wellbores drilled perpendicular to and parallel with beddings at reduced scale. The isotropic model is validated by comparing the stress distribution around borehole wall and along X axis direction with analytical solutions. Effects of different factors including the particle size distribution, borehole diameter, far-field stress anisotropy, and rock anisotropy are systematically evaluated on the stress distribution and borehole breakout propagation. Simulation results reveal that wider particle size distribution results in the local stress perturbations which cause localization of cracks. Reduction of borehole diameter significantly alters the crack failure from tensile to shear and raises the critical pressure. Rock anisotropy plays an important role on the stress state around wellbore which lead to the formation of preferred cracks under hydrostatic stress. Far-field stress anisotropy plays a dominant role in the shape of borehole breakout when drilled perpendicular to beddings while a secondary role when drilled parallel with beddings. Results from this study can provide fundamental insights on the underlying particle-scale mechanisms for previous findings in laboratory and field on borehole stability in anisotropic rock.

  1. SWAD: inherent photon counting performance of amorphous selenium multi-well avalanche detector

    NASA Astrophysics Data System (ADS)

    Stavro, Jann; Goldan, Amir H.; Zhao, Wei

    2016-03-01

    Photon counting detectors (PCDs) have the potential to improve x-ray imaging, however they are still hindered by several performance limitations and high production cost. By using amorphous Selenium (a-Se) the cost of PCDs can be significantly reduced compared to crystalline materials and enable large area detector fabrication. To overcome the problem of low carrier mobility and low charge conversion gain in a-Se, we are developing a novel direct conversion a- Se field-Shaping multi-Well Avalanche Detector (SWAD). SWAD circumvents the charge transport limitation by using a Frisch grid built within the readout circuit, reducing charge collection time to ~200 ns. Field shaping permits depth independent avalanche gain in wells, resulting in total conversion gain that is comparable to Si and CdTe. In the present work we investigate the effects of charge sharing and energy loss to understand the inherent photon counting performance for SWAD at x-ray energies used in breast imaging applications (20-50keV). The energy deposition profile for each interacting x-ray was determined with Monte Carlo simulation. For the energy ranges we are interested in, photoelectric interaction dominates, with a k-fluorescence yield of approximately 60%. Using a monoenergetic 45 keV beam incident on a target pixel in 400um of a-Se, our results show that only 20.42 % and 22.4 % of primary interacting photons have kfluorescence emissions which escape the target pixel for 100um and 85um pixel sizes respectively, demonstrating SWAD's potential for high spatial resolution applications.

  2. Binding of disparate transcriptional activators to nucleosomal DNA is inherently cooperative.

    PubMed Central

    Adams, C C; Workman, J L

    1995-01-01

    To investigate mechanisms by which multiple transcription factors access complex promoters and enhancers within cellular chromatin, we have analyzed the binding of disparate factors to nucleosome cores. We used a purified in vitro system to analyze binding of four activator proteins, two GAL4 derivatives, USF, and NF-kappa B (KBF1), to reconstituted nucleosome cores containing different combinations of binding sites. Here we show that binding of any two or all three of these factors to nucleosomal DNA is inherently cooperative. Thus, the binuclear Zn clusters of GAL4, the helix-loop-helix/basic domains of USF, and the rel domain of NF-kappa B all participated in cooperative nucleosome binding, illustrating that this effect is not restricted to a particular DNA-binding domain. Simultaneous binding by two factors increased the affinity of individual factors for nucleosomal DNA by up to 2 orders of magnitude. Importantly, cooperative binding resulted in efficient nucleosome binding by factors (USF and NF-kappa B) which independently possess little nucleosome-binding ability. The participation of GAL4 derivatives in cooperative nucleosome binding required only DNA-binding and dimerization domains, indicating that disruption of histone-DNA contacts by factor binding was responsible for the increased affinity of additional factors. Cooperative nucleosome binding required sequence-specific binding of all transcription factors, appeared to have spatial constraints, and was independent of the orientation of the binding sites on the nucleosome. These results indicate that cooperative nucleosome binding is a general mechanism that may play a significant role in loading complex enhancer and promoter elements with multiple diverse factors in chromatin and contribute to the generation of threshold responses and transcriptional synergy by multiple activator sites in vivo. PMID:7862134

  3. Inherent Instability of the Retinitis Pigmentosa P23H Mutant Opsin*

    PubMed Central

    Chen, Yuanyuan; Jastrzebska, Beata; Cao, Pengxiu; Zhang, Jianye; Wang, Benlian; Sun, Wenyu; Yuan, Yiyuan; Feng, Zhaoyang; Palczewski, Krzysztof

    2014-01-01

    The P23H opsin mutation is the most common cause of autosomal dominant retinitis pigmentosa. Even though the pathobiology of the resulting retinal degeneration has been characterized in several animal models, its complex molecular mechanism is not well understood. Here, we expressed P23H bovine rod opsin in the nervous system of Caenorhabditis elegans. Expression was low due to enhanced protein degradation. The mutant opsin was glycosylated, but the polysaccharide size differed from that of the normal protein. Although P23H opsin aggregated in the nervous system of C. elegans, the pharmacological chaperone 9-cis-retinal stabilized it during biogenesis, producing a variant of rhodopsin called P23H isorhodopsin. In vitro, P23H isorhodopsin folded correctly, formed the appropriate disulfide bond, could be photoactivated but with reduced sensitivity, and underwent Meta II decay at a rate similar to wild type isorhodopsin. In worm neurons, P23H isorhodopsin initiated phototransduction by coupling with the endogenous Gi/o signaling cascade that induced loss of locomotion. Using pharmacological interventions affecting protein synthesis and degradation, we showed that the chromophore could be incorporated either during or after mutant protein translation. However, regeneration of P23H isorhodopsin with chromophore was significantly slower than that of wild type isorhodopsin. This effect, combined with the inherent instability of P23H rhodopsin, could lead to the structural cellular changes and photoreceptor death found in autosomal dominant retinitis pigmentosa. These results also suggest that slow regeneration of P23H rhodopsin could prevent endogenous chromophore-mediated stabilization of rhodopsin in the retina. PMID:24515108

  4. Intergovernmental relations inherent in the Energy Management Partnership Act: a workshop on information requirements

    SciTech Connect

    Hoop, W.J.; Edelson, E.

    1980-02-01

    This paper summarizes the results of the first of three workshops that were planned to assess the information needed by the Office of Conservation and Solar Energy (CS) to effectively evaluate the pending Energy Management Partnership Act (EMPA); the workshop concentrated on issues of the EMPA hierarchical partnership. The approach utilized offers two major benefits to CS. First, by considering the problem of program evaluation while EMPA is still in the planning stage, this study identifies any baseline information that should be collected prior to implementation of EMPA, and also provides CS with the opportunity to include evaluation considerations in the operating guidelines for the program. Second, by identifying the potential problems and benefits inherent in EMPA and then identifying the information necessary to evaluate these problems and benefits, information requirements tied to the reasons for needing that information are generated, rather than a long unrelated laundry list of information requirements. Drafting of EMPA is not yet complete. When the term EMPA is used here, it refers to a set of bills that are presently being melded together. The original EMPA bill, which originated in DOE, was designed to expand the role of state and local governments in achieving national energy goals. Specifically, EMPA would provide a total of $110 million annually to state and local governments over a five year period to (1) develop an overall state energy plan, (2) consolidate three existing federal energy grant programs, (3) allow the secretary to fund directly innovative projects at the local level, and (4) provide additional assistance to states to cover the administrative costs of existing energy programs. Other bills, which may be passed in conjuncttion with EMPA or incorporated into EMPA, place additional emphasis on the local level by allocating as much as $400 million annually to local governments.

  5. Assessment of spectral, misregistration, and spatial uncertainties inherent in the cross-calibration study

    USGS Publications Warehouse

    Chander, G.; Helder, D.L.; Aaron, D.; Mishra, N.; Shrestha, A.K.

    2013-01-01

    Cross-calibration of satellite sensors permits the quantitative comparison of measurements obtained from different Earth Observing (EO) systems. Cross-calibration studies usually use simultaneous or near-simultaneous observations from several spaceborne sensors to develop band-by-band relationships through regression analysis. The investigation described in this paper focuses on evaluation of the uncertainties inherent in the cross-calibration process, including contributions due to different spectral responses, spectral resolution, spectral filter shift, geometric misregistrations, and spatial resolutions. The hyperspectral data from the Environmental Satellite SCanning Imaging Absorption SpectroMeter for Atmospheric CartograpHY and the EO-1 Hyperion, along with the relative spectral responses (RSRs) from the Landsat 7 Enhanced Thematic Mapper (TM) Plus and the Terra Moderate Resolution Imaging Spectroradiometer sensors, were used for the spectral uncertainty study. The data from Landsat 5 TM over five representative land cover types (desert, rangeland, grassland, deciduous forest, and coniferous forest) were used for the geometric misregistrations and spatial-resolution study. The spectral resolution uncertainty was found to be within 0.25%, spectral filter shift within 2.5%, geometric misregistrations within 0.35%, and spatial-resolution effects within 0.1% for the Libya 4 site. The one-sigma uncertainties presented in this paper are uncorrelated, and therefore, the uncertainties can be summed orthogonally. Furthermore, an overall total uncertainty was developed. In general, the results suggested that the spectral uncertainty is more dominant compared to other uncertainties presented in this paper. Therefore, the effect of the sensor RSR differences needs to be quantified and compensated to avoid large uncertainties in cross-calibration results.

  6. First Aid and Safety

    MedlinePlus

    ... First-Aid Kit Food Safety for Your Family Gun Safety Halloween Candy Hints Household Safety Checklists Household ... Climbing, and Grabbing Household Safety: Preventing Injuries From Firearms Household Safety: Preventing Injuries in the Crib Household ...

  7. Inherently Safe and Long-Life Fission Power System for Lunar Outposts

    NASA Astrophysics Data System (ADS)

    Schriener, T. M.; El-Genk, Mohamed S.

    Power requirements for future lunar outposts, of 10's to 100's kWe, can be fulfilled using nuclear reactor power systems. In addition to the long life and operation reliability, safety is paramount in all phases, including fabrication and assembly, launch, emplacement below grade on the lunar surface, operation, post-operation decay heat removal and long-term storage and eventual retrieval. This paper introduces the Solid Core-Sectored Compact Reactor (SC-SCoRe) and power system with static components and no single point failures. They ensure reliable continuous operation for ~21 years and fulfill the safety requirements. The SC-SCoRe nominally generates 1.0 MWth at liquid NaK-56 coolant inlet and exit temperatures of 850 K and 900 K and the power system provides 38 kWe at high DC voltage using SiGe thermoelectric (TE) conversion assemblies. In case of a loss of coolant or cooling in a reactor core sector, the power system continues to operate; generating ~4 kWe to the outpost for emergency life support needs. The post-operation storage of the reactor below grade on the lunar surface is a safe and practical choice. The total radioactivity in the reactor drops from ~1 million Ci, immediately at shutdown, to below 164 Ci after 300 years of storage. At such time, the reactor is retrieved safely with no contamination or environmental concerns.

  8. Playground Safety.

    ERIC Educational Resources Information Center

    Sipes, James L.

    2000-01-01

    Discusses the issues of risk, liability, and fun when landscaping playgrounds with safety in mind. The importance of playground surfaces and several preventive measures landscapers can use to reduce the risk of injury are discussed. Concluding comments address playground design features and liability. (GR)

  9. School Safety.

    ERIC Educational Resources Information Center

    The Newsletter of the Comprehensive Center-Region VI, 1999

    1999-01-01

    The articles in this issue dealing with school safety discusses what rural and small urban settings are doing to prevent violence and to educate young people about prosocial alternatives to violence. The research is quite clear that female, minority, and gay students are the targets of a disproportionate amount of harassment and violence, both in…

  10. Safety First!

    ERIC Educational Resources Information Center

    Longfield, Judith

    2006-01-01

    In this article, the author relates how a hands-on chemistry investigation provided her the inspiration to develop an effective safety lesson for her third grade chemistry class. She began the lesson by demonstrating the use of pH indicator paper to show that ordinary household (white) vinegar was an acid. With the students, she wondered aloud…

  11. Art Safety.

    ERIC Educational Resources Information Center

    BCATA Journal for Art Teachers, 1991

    1991-01-01

    Advocating that Canadian art programs should use and model environmentally safe practices, the articles in this journal focus on issues of safe practices in art education. Articles are: (1) "What is WHMIS?"; (2) "Safety Precautions for Specific Art Processes"; (3) "Toxic Substances"; (4) "Using Clay, Glazes, and Kilns Safely in the Classroom"…

  12. Safer Systems: A NextGen Aviation Safety Strategic Goal

    NASA Technical Reports Server (NTRS)

    Darr, Stephen T.; Ricks, Wendell R.; Lemos, Katherine A.

    2008-01-01

    The Joint Planning and Development Office (JPDO), is charged by Congress with developing the concepts and plans for the Next Generation Air Transportation System (NextGen). The National Aviation Safety Strategic Plan (NASSP), developed by the Safety Working Group of the JPDO, focuses on establishing the goals, objectives, and strategies needed to realize the safety objectives of the NextGen Integrated Plan. The three goal areas of the NASSP are Safer Practices, Safer Systems, and Safer Worldwide. Safer Practices emphasizes an integrated, systematic approach to safety risk management through implementation of formalized Safety Management Systems (SMS) that incorporate safety data analysis processes, and the enhancement of methods for ensuring safety is an inherent characteristic of NextGen. Safer Systems emphasizes implementation of safety-enhancing technologies, which will improve safety for human-centered interfaces and enhance the safety of airborne and ground-based systems. Safer Worldwide encourages coordinating the adoption of the safer practices and safer systems technologies, policies and procedures worldwide, such that the maximum level of safety is achieved across air transportation system boundaries. This paper introduces the NASSP and its development, and focuses on the Safer Systems elements of the NASSP, which incorporates three objectives for NextGen systems: 1) provide risk reducing system interfaces, 2) provide safety enhancements for airborne systems, and 3) provide safety enhancements for ground-based systems. The goal of this paper is to expose avionics and air traffic management system developers to NASSP objectives and Safer Systems strategies.

  13. Variability of particle size distribution with respect to inherent optical properties in Poyang Lake, China.

    PubMed

    Huang, Jue; Chen, Xiaoling; Jiang, Tao; Yang, Fanlin; Chen, Liqiong; Yan, Liwen

    2016-08-01

    Suspended particulate matter plays a significant role in the studies of sediment fluxes, phytoplankton dynamics, and water optical properties. This study focuses on the relationships between particle size distribution (PSD), water's inherent optical properties (IOPs), and water constituents. We investigated the complex waters of Poyang Lake, the largest freshwater lake in China, in wet and dry seasons during 2008-2011. Because of the distinct temporal-spatial variation of Poyang Lake, these parameters and relationships also demonstrate seasonal and regional variability. The variation range of the concentration of suspended particulate matter is 0.32-69.08  mg/l, with a mean value of 22.21  mg/l. The median particle size in the dry season is much larger than that of the wet season. The Junge distribution fits the PSD of Poyang Lake very well in the scope of 6.21-331 μm. Furthermore, the slopes of the PSD range from 3.54 to 4.69, with a mean value of 4.11, with the steepest slopes (>4.5) occurring in the waters around Songmen Mountain Island and the northern waterway. A negative correlation was found between median particle size (Dv50) and the mass-specific absorption coefficient at 443 nm [apm(443)] for both wet and dry seasons. Identical to analogous waters, the spectral slopes of the PSD correlate well with the spectral slopes of the attenuation coefficient, but with different fitted formulas. In the dry season, the particle size can better explain the variability of the scattering coefficient, while the mass-specific scattering coefficient is better explained by the apparent density. However, no similar results were found for the wet season. In addition, the spectral slopes of the backscattering coefficient correlated well with the PSD slope, and the bulk refractive index calculated from the backscattering ratio and PSD slope can indicate the particle composition of Poyang Lake. Overall, the knowledge on the PSD and IOPs gained in this study

  14. The research of edge extraction and target recognition based on inherent feature of objects

    NASA Astrophysics Data System (ADS)

    Xie, Yu-chan; Lin, Yu-chi; Huang, Yin-guo

    2008-03-01

    Current research on computer vision often needs specific techniques for particular problems. Little use has been made of high-level aspects of computer vision, such as three-dimensional (3D) object recognition, that are appropriate for large classes of problems and situations. In particular, high-level vision often focuses mainly on the extraction of symbolic descriptions, and pays little attention to the speed of processing. In order to extract and recognize target intelligently and rapidly, in this paper we developed a new 3D target recognition method based on inherent feature of objects in which cuboid was taken as model. On the basis of analysis cuboid nature contour and greyhound distributing characteristics, overall fuzzy evaluating technique was utilized to recognize and segment the target. Then Hough transform was used to extract and match model's main edges, we reconstruct aim edges by stereo technology in the end. There are three major contributions in this paper. Firstly, the corresponding relations between the parameters of cuboid model's straight edges lines in an image field and in the transform field were summed up. By those, the aimless computations and searches in Hough transform processing can be reduced greatly and the efficiency is improved. Secondly, as the priori knowledge about cuboids contour's geometry character known already, the intersections of the component extracted edges are taken, and assess the geometry of candidate edges matches based on the intersections, rather than the extracted edges. Therefore the outlines are enhanced and the noise is depressed. Finally, a 3-D target recognition method is proposed. Compared with other recognition methods, this new method has a quick response time and can be achieved with high-level computer vision. The method present here can be used widely in vision-guide techniques to strengthen its intelligence and generalization, which can also play an important role in object tracking, port AGV, robots

  15. Remote sensing reflectance and inherent optical properties in the mid Chesapeake Bay

    NASA Astrophysics Data System (ADS)

    Tzortziou, Maria; Subramaniam, Ajit; Herman, Jay R.; Gallegos, Charles L.; Neale and, Patrick J., Jr.; Harding, Lawrence W.

    2007-03-01

    We used an extensive set of bio-optical data to examine the relationships between inherent optical properties and remotely sensed quantities in an optically complex and biologically productive region of the Chesapeake Bay. Field observations showed that the chlorophyll algorithms used by the MODIS (MODerate resolution Imaging Spectroradiometer) ocean color sensor (i.e. Chlor_a, chlor_MODIS, chlor_a_3 products) do not perform accurately in these Case 2 waters. This is because, at high concentrations of chlorophyll, all MODIS algorithms are based on empirical relationships between chlorophyll concentration and blue:green wavelength remote sensing reflectance ( Rrs) ratios that do not account for the typically strong blue-wavelength absorption by non-covarying, dissolved and non-algal particulate components. We found stronger correlation between chlorophyll concentration and red:green Rrs ratios (i.e. Rrs(677)/ Rrs(554)). Regionally-specific algorithms that are based on the phytoplankton optical properties in the red wavelength region provide a better basis for satellite monitoring of phytoplankton blooms in these Case 2 waters. Our estimates of f/ Q (proportionality factor in the relationship between Rrs and the ratio of water backscattering, bb, and absorption, a, coefficients, bb/( a + bb)) were not considerably different from f/ Q previously estimated for same measurement geometry but Case 1 waters. Variation in surface bb significantly affected Rrs magnitude across the visible spectrum and was most strongly correlated ( R2 = 0.88) with observed variability in Rrs at 670 nm. Surface values of particulate backscattering were strongly correlated with non-algal particulate absorption, anap ( R2 = 0.83). These results, along with the measured backscattering fraction and non-algal particulate absorption spectral slope, indicate that suspended non-algal particles with high inorganic content are the major water constituents regulating bb variability in the studied region

  16. Inherent paramagnetic defects in layered Si/SiO2 superstructures with Si nanocrystals

    NASA Astrophysics Data System (ADS)

    Jivanescu, M.; Stesmans, A.; Zacharias, M.

    2008-11-01

    An extensive electron spin resonance (ESR) analysis has been carried out on structures comprised of Si nanoparticles (˜2 nm across) embedded in a regular pattern in an amorphous SiO2 matrix, fabricated by the SiO/SiO2 superlattice approach, with the intent to reveal and quantify occurring paramagnetic defects. The as-grown state is found to exhibit only a Si dangling bond (DB) signal, which through combination of first and second harmonic X-, K-, and Q-band observations in combination with computer spectra simulation, could be conclusively disentangled as solely comprised of overlapping powder pattern spectra of Pb(0) and Pb1 defects, the archetypal intrinsic defects of the Si/SiO2 interface, with no evidence for a D line (Si DBs in disordered Si). This indicates a full crystalline system of randomly oriented Si nanocrystals (NCs). The Pb(0)/Pb1 defect system, pertaining to the NC-Si/SiO2 interfaces, is found to be both qualitatively and quantitatively much alike that of standard (high-quality) thermal Si/SiO2. The system is inherent, remaining unaffected by subsequent UV/vacuum UV irradiations. Relying on the known properties of Pb-type defects in standard microscopic Si/SiO2, the data would comply with Si nanocrystallites, in average, predominantly bordered by (111) and (100) facets, perhaps with morphology, schematically, of [100] truncated (111) octahedrons. Based on independent NC particles counting, there appears a Pb-type center at ˜71% of the Si NCs indicating the latter to be comprised of two subsystems-with or without an incorporated strain relaxing interface defect-which in that case will exhibit drastically different defect-sensitive properties, such as, e.g., photoluminescence (PL). Upon additional optical irradiation, two more defects appear, i.e., the SiO2-associated Eγ' and EX centers, where the observed density of the former, taken as criterion, indicates the SiO2 matrix to be of standard thermal oxide quality. Thus, the properties of the

  17. Selective nature and inherent variability of interrill erosion across prolonged rainfall simulation

    NASA Astrophysics Data System (ADS)

    Hu, Y.; Kuhn, N. J.; Fister, W.

    2012-04-01

    Sediment of interrill erosion has been generally recognized to be selectively enriched with soil organic carbon (SOC) and fine fractions (clay/silt-sized particles or aggregates) in comparison to source area soil. Limited kinetic energy and lack of concentrated runoff are the dominant factors causing selective detachment and transportation. Although enrichment ratios of SOC (ERsoc) in eroded sediment were generally reported > 1, the values varied widely. Causal factors to variation, such as initial soil properties, rainfall properties and experimental conditions, have been extensively discussed. But less attention was directed to the potential influence of prolonged rainfall time onto the temporal pattern of ERsoc. Conservation of mass dictates that ERsoc must be balanced by a decline in the source material which should also lead to a reduced or even negative ERsoc in sediment over time. Besides, the stabilizing effects of structural crust on reducing erosional variation, and the unavoidable variations of erosional response induced by the inherent complexity of interrill erosion, have scarcely been integrated. Moreover, during a prolonged rainfall event surface roughness evolves and affects the movement of eroded aggregates and mineral particles. In this study, two silt loams from Möhlin, Switzerland, organically (OS) and conventionally farmed (CS), were exposed to simulated rainfall of 30 mm h-1 for up to 6 hours. Round donut-flumes with a confined eroding area (1845 cm2) and limited transporting distance (20 cm) were used. Sediments, runoff and subsurface flow were collected in intervals of 30 min. Loose aggregates left on the eroded soil surface, crusts and the soil underneath the crusts were collected after the experiment. All the samples were analyzed for total organic carbon (TOC) content, and texture. Laser scanning of soil surface was applied before and after the rainfall event. The whole experiment was repeated for 10 times. Results from this study showed

  18. The Practical Importance of Inherency Analysis for Public Advocates: Rhetorical Leadership in Framing a Supportive Social Climate for Education Reforms

    ERIC Educational Resources Information Center

    Olson, Kathryn M.

    2008-01-01

    This essay argues that teaching rhetorical leadership, particularly the skill of inherency analysis, is crucial to preparing effective citizen leaders. Using the example of education reforms for children with disabilities, it illustrates the practical value for those interested in public concerns of understanding and using analysis of the…

  19. How to Conduct Research on the Inherent Moral Significance of Teaching: A Phenomenological Elaboration of the Standard Repertory Grid Application

    ERIC Educational Resources Information Center

    van Kan, Carlos A.; Ponte, Petra; Verloop, Nico

    2010-01-01

    George Kelly's repertory grid application seems a promising method for researching the moral significance of teaching from a "life world" perspective. However, we encountered several challenges employing the repertory grid in its standard form for an inquiry into the inherent moral significance of teachers' everyday classroom interactions. In this…

  20. Simultaneous, inherently temperature and strain insensitive bio-sensors based on dual-resonance long-period gratings

    NASA Astrophysics Data System (ADS)

    Mani Tripathi, Saurabh; Verma, Deep Shikha; Bock, Wojtek J.; Mikulic, Predrag

    2016-05-01

    Addressing temperature and strain induced cross-talks simultaneously, we propose an inherently strain and temperature insensitive fiber-optic bio-sensor. The insensitivity has been achieved by properly adjusting the dopants and their concentrations, and by optimizing the grating period and the strength of concatenated dual-resonance long-period-gratings.

  1. Low-order dynamic modeling of the Experimental Breeder Reactor II

    SciTech Connect

    Berkan, R.C. . Dept. of Nuclear Engineering); Upadhyaya, B.R.; Kisner, R.A. )

    1990-07-01

    This report describes the development of a low-order, linear model of the Experimental Breeder Reactor II (EBR-II), including the primary system, intermediate heat exchanger, and steam generator subsystems. The linear model is developed to represent full-power steady state dynamics for low-level perturbations. Transient simulations are performed using model building and simulation capabilities of the computer software Matrix{sub x}. The inherently safe characteristics of the EBR-II are verified through the simulation studies. The results presented in this report also indicate an agreement between the linear model and the actual dynamics of the plant for several transients. Such models play a major role in the learning and in the improvement of nuclear reactor dynamics for control and signal validation studies. This research and development is sponsored by the Advanced Controls Program in the Instrumentation and Controls Division of the Oak Ridge National Laboratory. 17 refs., 67 figs., 15 tabs.

  2. Safety harness

    DOEpatents

    Gunter, Larry W.

    1993-01-01

    A safety harness to be worn by a worker, especially a worker wearing a plastic suit thereunder for protection in a radioactive or chemically hostile environment, which safety harness comprises a torso surrounding portion with at least one horizontal strap for adjustably securing the harness about the torso, two vertical shoulder straps with rings just forward of the of the peak of the shoulders for attaching a life-line and a pair of adjustable leg supporting straps releasibly attachable to the torso surrounding portion. In the event of a fall, the weight of the worker, when his fall is broken and he is suspended from the rings with his body angled slightly back and chest up, will be borne by the portion of the leg straps behind his buttocks rather than between his legs. Furthermore, the supporting straps do not restrict the air supplied through hoses into his suit when so suspended.

  3. Safety valve

    DOEpatents

    Bergman, Ulf C.

    1984-01-01

    The safety valve contains a resilient gland to be held between a valve seat and a valve member and is secured to the valve member by a sleeve surrounding the end of the valve member adjacent to the valve seat. The sleeve is movable relative to the valve member through a limited axial distance and a gap exists between said valve member and said sleeve.

  4. Farm Safety

    PubMed Central

    Wilson, G. S.

    1966-01-01

    Accident and safety are related terms; the higher the accident rate in any industry, the greater is the need for safety measures designed to prevent accidents. This article discusses the accident and safety problems in agriculture, which includes horticulture and forestry. There is still a tendency among townspeople to think of the countryside as peaceful and tranquil, a place where nothing happens very quickly and far removed from violent death or crippling injury. This pleasant rustic picture has undergone a striking change in the last 30 years owing to considerable agricultural mechanization and the development of chemical pesticides, which have brought new dangers to those who live and work on the land. Although men have readily adapted themselves to new machines and methods, they have not proved as able to recognize new dangers and learn how to guard against them. In consequence, accidents have increased to such an extent that the whole industry has realized the need for positive preventive measures. In this country, it is generally accepted that an employer of labour has a responsibility to provide safe working conditions for those he employs. Farm safety legislation goes a little further and usually requires an employer to provide necessary safeguards, with the added requirement on a worker to make use of them. It is a feature of accident prevention work that it never reaches a stage when it can be regarded as complete. Even when a reduction in accidents has been achieved, the effort must be sustained or the trend will be quickly reversed. Images PMID:5904095

  5. Weight Loss Decreases Inherent and Allergic Methacholine Hyperresponsiveness in Mouse Models of Diet-Induced Obese Asthma.

    PubMed

    Ather, Jennifer L; Chung, Michael; Hoyt, Laura R; Randall, Matthew J; Georgsdottir, Anna; Daphtary, Nirav A; Aliyeva, Minara I; Suratt, Benjamin T; Bates, Jason H T; Irvin, Charles G; Russell, Sheila R; Forgione, Patrick M; Dixon, Anne E; Poynter, Matthew E

    2016-08-01

    Obese asthma presents with inherent hyperresponsiveness to methacholine or augmented allergen-driven allergic asthma, with an even greater magnitude of methacholine hyperresponsiveness. These physiologic parameters and accompanying obese asthma symptoms can be reduced by successful weight loss, yet the underlying mechanisms remain incompletely understood. We implemented mouse models of diet-induced obesity, dietary and surgical weight loss, and environmental allergen exposure to examine the mechanisms and mediators of inherent and allergic obese asthma. We report that the methacholine hyperresponsiveness in these models of inherent obese asthma and obese allergic asthma manifests in distinct anatomical compartments but that both are amenable to interventions that induce substantial weight loss. The inherent obese asthma phenotype, with characteristic increases in distal airspace tissue resistance and tissue elastance, is associated with elevated proinflammatory cytokines that are reduced with dietary weight loss. Surprisingly, bariatric surgery-induced weight loss further elevates these cytokines while reducing methacholine responsiveness to levels similar to those in lean mice or in formerly obese mice rendered lean through dietary intervention. In contrast, the obese allergic asthma phenotype, with characteristic increases in central airway resistance, is not associated with increased adaptive immune responses, yet diet-induced weight loss reduces methacholine hyperresponsiveness without altering immunological variables. Diet-induced weight loss is effective in models of both inherent and allergic obese asthma, and our examination of the fecal microbiome revealed that the obesogenic Firmicutes/Bacteroidetes ratio was normalized after diet-induced weight loss. Our results suggest that structural, immunological, and microbiological factors contribute to the manifold presentations of obese asthma. PMID:27064658

  6. Inherent paramagnetic defects in layered Si/SiO{sub 2} superstructures with Si nanocrystals

    SciTech Connect

    Jivanescu, M.; Stesmans, A.; Zacharias, M.

    2008-11-15

    An extensive electron spin resonance (ESR) analysis has been carried out on structures comprised of Si nanoparticles ({approx}2 nm across) embedded in a regular pattern in an amorphous SiO{sub 2} matrix, fabricated by the SiO/SiO{sub 2} superlattice approach, with the intent to reveal and quantify occurring paramagnetic defects. The as-grown state is found to exhibit only a Si dangling bond (DB) signal, which through combination of first and second harmonic X-, K-, and Q-band observations in combination with computer spectra simulation, could be conclusively disentangled as solely comprised of overlapping powder pattern spectra of P{sub b(0)} and P{sub b1} defects, the archetypal intrinsic defects of the Si/SiO{sub 2} interface, with no evidence for a D line (Si DBs in disordered Si). This indicates a full crystalline system of randomly oriented Si nanocrystals (NCs). The P{sub b(0)}/P{sub b1} defect system, pertaining to the NC-Si/SiO{sub 2} interfaces, is found to be both qualitatively and quantitatively much alike that of standard (high-quality) thermal Si/SiO{sub 2}. The system is inherent, remaining unaffected by subsequent UV/vacuum UV irradiations. Relying on the known properties of P{sub b}-type defects in standard microscopic Si/SiO{sub 2}, the data would comply with Si nanocrystallites, in average, predominantly bordered by (111) and (100) facets, perhaps with morphology, schematically, of [100] truncated (111) octahedrons. Based on independent NC particles counting, there appears a P{sub b}-type center at {approx}71% of the Si NCs indicating the latter to be comprised of two subsystems-with or without an incorporated strain relaxing interface defect-which in that case will exhibit drastically different defect-sensitive properties, such as, e.g., photoluminescence (PL). Upon additional optical irradiation, two more defects appear, i.e., the SiO{sub 2}-associated E{sub {gamma}}{sup '} and EX centers, where the observed density of the former, taken as

  7. Nuclear safety as applied to space power reactor systems

    SciTech Connect

    Cummings, G.E.

    1987-01-01

    To develop a strategy for incorporating and demonstrating safety, it is necessary to enumerate the unique aspects of space power reactor systems from a safety standpoint. These features must be differentiated from terrestrial nuclear power plants so that our experience can be applied properly. Some ideas can then be developed on how safe designs can be achieved so that they are safe and perceived to be safe by the public. These ideas include operating only after achieving a stable orbit, developing an inherently safe design, ''designing'' in safety from the start and managing the system development (design) so that it is perceived safe. These and other ideas are explored further in this paper.

  8. SAFR: a marriage of safety and innovation in LMR design

    SciTech Connect

    Lancet, R.T.; Mills, J.C.

    1985-11-01

    The Sodium Advanced Fast Reactor (SAFR) is a natural evolution of earlier designs, given the current economic and licensing environment. Stringent safety and economic goals have been established for the SAFR plant. This paper describes how these goals are being satisfied, with the primary emphasis being placed on safety. The top level safety goals are: (a) to provide inherently safe responses to all credible events (b) to minimize the potential for severe accidents, and (c) to eliminate the need for evacuation, (d) limited financial risk, (e) assured investment protection, (f) minimum development risk, (g) high capacity factor, (h) long plant life, and (i) low personnel radiation exposure.

  9. Safety and Liability.

    ERIC Educational Resources Information Center

    Berthelot, Ronald J.; And Others

    1982-01-01

    This series of five articles highlights Pensacola Junior College's occupational safety course, involving simulated emergencies, Florida's standards for teacher liability, electrical safety in the classroom and laboratory, color coding for machine safety, and Florida industrial arts safety instructional materials. (SK)

  10. Safety Grooving

    NASA Technical Reports Server (NTRS)

    1985-01-01

    Safety grooving, the cutting of grooves in concrete to increase traction and prevent injury, was first developed to reduce aircraft accidents on wet runways. Represented by the International Grooving and Grinding Association (IG&GA), the industry expanded into highway and pedestrian applications. The technique originated at Langley, which assisted in testing the grooving at airports and on highways. Skidding was reduced, stopping distance decreased, and a vehicle's cornering ability on curves was increased. The process has been extended to animal holding pens, steps, parking lots and other potentially slippery surfaces.

  11. Delivering safety

    SciTech Connect

    Baldwin, N.D.; Spooner, K.G.; Walkden, P.

    2007-07-01

    In the United Kingdom there have been significant recent changes to the management of civil nuclear liabilities. With the formation in April 2005 of the Nuclear Decommissioning Authority (NDA), ownership of the civil nuclear licensed sites in the UK, including the Magnox Reactor Stations, passed to this new organisation. The NDAs mission is to seek acceleration of the nuclear clean up programme and deliver increased value for money and, consequently, are driving their contractors to seek more innovative ways of performing work. British Nuclear Group manages the UK Magnox stations under contract to the NDA. This paper summarises the approach being taken within its Reactor Sites business to work with suppliers to enhance working arrangements at sites, improve the delivery of decommissioning programmes and deliver improvements in safety and environmental performance. The UK Magnox stations are 1. generation gas-graphite reactors, constructed in the 1950's and 1960's. Two stations are currently still operating, three are shut-down undergoing defueling and the other five are being decommissioned. Despite the distractions of industry restructuring, an uncompromising policy of demanding improved performance in conjunction with improved safety and environmental standards has been adopted. Over the past 5 years, this policy has resulted in step-changes in performance at Reactor Sites, with increased electrical output and accelerated defueling and decommissioning. The improvements in performance have been mirrored by improvements in safety (DACR of 0 at 5 sites); environmental standards (reductions in energy and water consumption, increased waste recycling) and the overall health of the workforce (20% reduction in sickness absence). These achievements have, in turn, been recognised by external bodies, resulting in several awards, including: the world's first ISRS and IERS level 10 awards (Sizewell, 2006), the NUMEX plant maintenance award (Bradwell, 2006), numerous Ro

  12. Synchrotron Infrared Spectroscopy with Multivariate Spectral Analyses Potentially Facilitates the Classification of Inherent Structures of Feed-Type of Sorghum

    SciTech Connect

    Yu Peiqiang; Damiran, Daalkhaijav; Liu Dasen

    2010-02-03

    The objective of this study was to investigate the inherent structural-chemical features of Chinese feed-type sorghum seed using synchrotron-radiation Fourier transform infrared microspectroscopy (SRFTIRM) with two multivariate molecular spectral analysis techniques: Agglomerative Hierarchical cluster (AHCA) and principal component analyses (PCA). The results show that by application of these two multivariate techniques with the infrared spectroscopy of the SRFTIRM, it makes possible to discriminate and classify the inherent molecular structural features among the different layers of sorghum with a great efficiency. With the SRFTIRM, images of the molecular chemistry of sorghum could be generated at an ultra-spatial resolution. The features of nutrient matrix and nutrient make-up and interactions could be revealed.

  13. A PRA case study of extended long term decay heat removal for shutdown risk assessment

    SciTech Connect

    Roglans, J.; Ragland, W.A.; Hill, D.J.

    1992-12-01

    A Probabilistic Risk Assessment (PRA) of the Experimental Breeder Reactor II (EBR-II), a Department of Energy (DOE) Category A research reactor, has recently been completed at Argonne National Laboratory (ANL). The results of this PRA have shown that the decay heat removal system for EBR-II is extremely robust and reliable. In addition, the methodology used demonstrates how the actions of other systems not normally used for actions of other systems not normally used for decay heat removal can be used to expand the mission time of the decay heat removal system and further increase its reliability. The methodology may also be extended to account for the impact of non-safety systems in enhancing the reliability of other dedicated safety systems.

  14. A PRA case study of extended long term decay heat removal for shutdown risk assessment

    SciTech Connect

    Roglans, J.; Ragland, W.A.; Hill, D.J.

    1992-01-01

    A Probabilistic Risk Assessment (PRA) of the Experimental Breeder Reactor II (EBR-II), a Department of Energy (DOE) Category A research reactor, has recently been completed at Argonne National Laboratory (ANL). The results of this PRA have shown that the decay heat removal system for EBR-II is extremely robust and reliable. In addition, the methodology used demonstrates how the actions of other systems not normally used for actions of other systems not normally used for decay heat removal can be used to expand the mission time of the decay heat removal system and further increase its reliability. The methodology may also be extended to account for the impact of non-safety systems in enhancing the reliability of other dedicated safety systems.

  15. A thematic approach to system safety

    SciTech Connect

    Ekman, M.E.; Werner, P.W.; Covan, J.M.; D`Antonio, P.E.

    1997-12-01

    Sandia National Laboratories has refined a process for developing inherently safer system designs, based on methods used by the Laboratories to design detonation safety into nuclear weapons. The process was created when the Laboratories realized that standard engineering practices did not provide the level of safety assurance necessary for nuclear weapon operations, with their potential for catastrophic accidents. A systematic approach, which relies on mutually supportive design principles integrated through fundamental physical principles, was developed to ensure a predictably safe system response under a variety of operational and accident based stresses. Robust, safe system designs result from this thematic approach to safety, minimizing the number of safety critical features. This safety assurance process has two profound benefits: the process avoids the need to understand or limit the ultimate intensity of off normal environments and it avoids the requirement to analyze and test a bewildering and virtually infinite array of accident environment scenarios (e.g., directional threats, sequencing of environments, time races, etc.) to demonstrate conformance to all safety requirements.

  16. POST-OPERATIONAL TREATMENT OF RESIDUAL NA COOLLANT IN EBR-2 USING CARBONATION

    SciTech Connect

    Sherman, S.; Knight, C.

    2011-03-08

    At the end of 2002, the Experimental Breeder Reactor Two (EBR-II) facility became a U.S. Resource Conservation and Recovery Act (RCRA) permitted site, and the RCRA permit1 compelled further treatment of the residual sodium in order to convert it into a less reactive chemical form and remove the by-products from the facility, so that a state of RCRA 'closure' for the facility may be achieved (42 U.S.C. 6901-6992k, 2002). In response to this regulatory driver, and in recognition of project budgetary and safety constraints, it was decided to treat the residual sodium in the EBR-II primary and secondary sodium systems using a process known as 'carbonation.' In early EBR-II post-operation documentation, this process is also called 'passivation.' In the carbonation process (Sherman and Henslee, 2005), the system containing residual sodium is flushed with humidified carbon dioxide (CO{sub 2}). The water vapor in the flush gas reacts with residual sodium to form sodium hydroxide (NaOH), and the CO{sub 2} in the flush gas reacts with the newly formed NaOH to make sodium bicarbonate (NaHCO{sub 3}). Hydrogen gas (H{sub 2}) is produced as a by-product. The chemical reactions occur at the exposed surface of the residual sodium. The NaHCO{sub 3} layer that forms is porous, and humidified carbon dioxide can penetrate the NaHCO{sub 3} layer to continue reacting residual sodium underneath. The rate of reaction is controlled by the thickness of the NaHCO{sub 3} surface layer, the moisture input rate, and the residual sodium exposed surface area. At the end of carbonation, approximately 780 liters of residual sodium in the EBR-II primary tank ({approx}70% of original inventory), and just under 190 liters of residual sodium in the EBR-II secondary sodium system ({approx}50% of original inventory), were converted into NaHCO{sub 3}. No bare surfaces of residual sodium remained after treatment, and all remaining residual sodium deposits are covered by a layer of NaHCO{sub 3}. From a

  17. The effects of variability in the inherent optical properties on estimations of chlorophyll a by remote sensing in Swedish freshwaters.

    PubMed

    Strömbeck, N; Pierson, D C

    2001-03-14

    During late summer of 1997 measurements were made of the inherent optical properties in Lake Mälaren, Sweden. These included measurements of the total particulate absorption, phytoplankton absorption, yellow substance absorption and total backscattering. Measurements were also made of concentrations known to affect the inherent optical properties; chlorophyll a and suspended particulate organic and inorganic matter. At the same time measurements of underwater radiance reflectance were made. The above measurements were used to better define the relationships between the inherent optical properties and the concentrations affecting them. Correlation analyses were also made in order to study covariation of the concentrations of suspended and dissolved substances in the data set. These relationships were then used to better parameterize a semi-analytical model predicting remote sensing reflectance. Multivariate sensitivity analyses showed that large variations on the Rr(700-710)/Rr(678-685) ratio vs. chlorophyll concentrations could be expected in a heterogeneous environment such as Lake Mälaren. This could lead to large errors in subsequent estimates of chlorophyll concentrations. PMID:11315736

  18. A study of the problem of designing airplanes with satisfactory inherent damping of the dutch roll oscillation

    NASA Technical Reports Server (NTRS)

    Campbell, John P; Mckinney, Marion O , Jr

    1954-01-01

    Considerable interest has recently been shown in means of obtaining satisfactory stability of the dutch roll oscillation for modern high-performance airplanes without resort to complicated artificial stabilizing devices. One approach to this problem is to lay out the airplane in the earliest stages of design so that it will have the greatest practicable inherent stability of the lateral oscillation. The present report presents some preliminary results of a theoretical analysis to determine the design features that appear most promising in providing adequate inherent stability. These preliminary results cover the case of fighter airplanes at subsonic speeds. The investigation indicated that it is possible to design fighter airplanes to have substantially better inherent stability than most current designs. Since the use of low-aspect-ratio swept-back wings is largely responsible for poor dutch roll stability, it is important to design the airplane with the maximum aspect ratio and minimum sweep that will permit attainment of the desired performance. The radius of gyration in roll should be kept as low as possible and the nose-up inclination of the principal longitudinal axis of inertia should be made as great as practicable. (author)

  19. Summary of FY 1997 related to JAPC-U.S. DOE contract study on improvement of core safety -- study on GEM (III)

    SciTech Connect

    Burke, T.M.

    1998-02-03

    FFTF was originally designed/constructed/operated to develop LMFBR fuels and materials. Inherent safety became a major focus of the US nuclear industry in the mid 1980`s. The inherent safety characteristics of LMFBRs were recognized but additional enhancement was desired. The presentation contents are: Fast Flux Test Facility history and status; Overview of contract activities; Summary of loss of flow without scram with GEMs testing; and Summary of pump start with GEMs testing.

  20. Plant-Based Assessment of Inherent Soil Productivity and Contributions to China’s Cereal Crop Yield Increase since 1980

    PubMed Central

    Fan, Mingsheng; Lal, Rattan; Cao, Jian; Qiao, Lei; Su, Yansen; Jiang, Rongfeng; Zhang, Fusuo

    2013-01-01

    Objective China’s food production has increased 6-fold during the past half-century, thanks to increased yields resulting from the management intensification, accomplished through greater inputs of fertilizer, water, new crop strains, and other Green Revolution’s technologies. Yet, changes in underlying quality of soils and their effects on yield increase remain to be determined. Here, we provide a first attempt to quantify historical changes in inherent soil productivity and their contributions to the increase in yield. Methods The assessment was conducted based on data-set derived from 7410 on-farm trials, 8 long-term experiments and an inventory of soil organic matter concentrations of arable land. Results Results show that even without organic and inorganic fertilizer addition crop yield from on-farm trials conducted in the 2000s was significantly higher compared with those in the 1980s — the increase ranged from 0.73 to 1.76 Mg/ha for China’s major irrigated cereal-based cropping systems. The increase in on-farm yield in control plot since 1980s was due primarily to the enhancement of soil-related factors, and reflected inherent soil productivity improvement. The latter led to higher and stable yield with adoption of improved management practices, and contributed 43% to the increase in yield for wheat and 22% for maize in the north China, and, 31%, 35% and 22% for early and late rice in south China and for single rice crop in the Yangtze River Basin since 1980. Conclusions Thus, without an improvement in inherent soil productivity, the ‘Agricultural Miracle in China’ would not have happened. A comprehensive strategy of inherent soil productivity improvement in China, accomplished through combining engineering-based measures with biological-approaches, may be an important lesson for the developing world. We propose that advancing food security in 21st century for both China and other parts of world will depend on continuously improving inherent soil

  1. Safety analysis

    NASA Technical Reports Server (NTRS)

    Knight, John C.

    1995-01-01

    We are engaged in a research program in safety-critical computing that is based on two case studies. We use these case studies to provide application-specific details of the various research issues, and as targets for evaluation of research ideas. The first case study is the Magnetic Stereotaxis System (MSS), an investigational device for performing human neurosurgery being developed in a joint effort between the Department of Physics at the University of Virginia and the Department of Neurosurgery at the University of Iowa. The system operates by manipulating a small permanent magnet (known as a 'seed') within the brain using an externally applied magnetic field. By varying the magnitude and gradient of the external magnetic field, the seed can be moved along a non-linear path and positioned at a site requiring therapy, e.g., a tumor. The magnetic field required for movement through brain tissue is extremely high, and is generated by a set of six superconducting magnets located in a housing surrounding the patient's head. The system uses two X-ray cameras positioned at right angles to detect in real time the locations of the seed and of X-ray opaque markers affixed to the patient's skull. the X-ray images are used to locate the objects of interest in a canonical frame of reference. the second case study is the University of Virginia Research Nuclear Reactor (UVAR). It is a 2 MW thermal, concrete-walled pool reactor. The system operates using 20 to 25 plate-type fuel assemblies placed on a rectangular grid plate. There are three scramable safety rods, and one non-scramable regulating rod that can be put in automatic mode. It was originally constructed in 1959 as a 1 MW system, and it was upgraded to 2 MW in 1973. Though only a research reactor rather than a power reactor, the issues raised are significant and can be related to the problems faced by full-scale reactor systems.

  2. Temperature and burnup correlated fuel-cladding chemical interaction in U-10ZR metallic fuel

    NASA Astrophysics Data System (ADS)

    Carmack, William J.

    Metallic fuels are proposed for use in advanced sodium cooled fast reactors and provide a number of advantages over other fuel types considering their fabricability, performance, recyclability, and safety. Resistance to cladding "breach" and subsequent release of fission products and fuel constituents to the nuclear power plant primary coolant system is a key performance parameter for a nuclear fuel system. In metallic fuel, FCCI weakens the cladding, especially at high power-high temperature operation, contributing to fuel pin breach. Empirical relationships for FCCI have been developed from a large body of data collected from in-pile (EBR-II) and out-of-pile experiments [1]. However, these relationships are unreliable in predicting FCCI outside the range of EBR-II experimental data. This dissertation examines new FCCI data extracted from the MFF-series of prototypic length metallic fuel irradiations performed in the Fast Flux Test Facility (FFTF). The fuel in these assemblies operated a temperature and burnup conditions similar to that in EBR-II but with axial fuel height three times longer than EBR-II experiments. Comparing FCCI formation data from FFTF and EBR-II provides new insight into FCCI formation kinetics. A model is developed combining both production and diffusion of lanthanides to the fuel-cladding interface and subsequent reaction with the cladding. The model allows these phenomena to be influenced by fuel burnup (lanthanide concentrations) and operating temperature. Parameters in the model are adjusted to reproduce measured FCCI layer thicknesses from EBR-II and FFTF. The model predicts that, under appropriate conditions, rate of FCCI formation can be controlled by either fission product transport or by the reaction rate of the interaction species at the fuel-cladding interface. This dissertation will help forward the design of metallic fuel systems for advanced sodium cooled fast reactors by allowing the prediction of FCCI layer formation in full

  3. Rebuilding a safety culture

    NASA Astrophysics Data System (ADS)

    Rodney, George A.

    1991-11-01

    The development of a culture of safety and NASA since the Challenger accident is reviewed. The technical elements of the strengthened NASA safety program are described, including problem reporting, risk/assessment/risk management, operational safety, and safety assurance are addressed. Future directions in the development of safety are considered.

  4. Safety in the Workplace.

    ERIC Educational Resources Information Center

    Shaw, Richard

    1999-01-01

    Addresses workplace safety needs and tips for helping an organization achieve a high level of safety. Tips include showing administration commitment, establishing retribution-free reporting of safety problems and violations, rewarding excellent safety effort, and allowing no compromises in following safety procedures. (GR)

  5. Rebuilding a safety culture

    NASA Technical Reports Server (NTRS)

    Rodney, George A.

    1991-01-01

    The development of a culture of safety and NASA since the Challenger accident is reviewed. The technical elements of the strengthened NASA safety program are described, including problem reporting, risk/assessment/risk management, operational safety, and safety assurance are addressed. Future directions in the development of safety are considered.

  6. Logistic risk model for the unique effects of inherent aerobic capacity on +Gz tolerance before and after simulated weightlessness.

    PubMed

    Ludwig, D A; Convertino, V A; Goldwater, D J; Sandler, H

    1987-11-01

    Small sample size (n less than 10) and inappropriate analysis of multivariate data have hindered previous attempts to describe which physiologic and demographic variables are most important in determining how long humans can tolerate acceleration. Data from previous centrifuge studies conducted at NASA/Ames Research Center, utilizing a 7-14 d bed rest protocol to simulate weightlessness, were included in the current investigation. After review, data on 25 women and 22 men were available for analysis. Study variables included gender, age, weight, height, percent body fat, resting heart rate, mean arterial pressure, VO2max, and plasma volume. Since the dependent variable was time to greyout (failure), two contemporary biostatistical modeling procedures (proportional hazard and logistic discriminant function) were used to estimate risk, given a particular subject's profile. After adjusting for pre-bed-rest tolerance time, none of the profile variables remained in the risk equation for post-bed-rest tolerance greyout. However, prior to bed rest, risk of greyout could be predicted with 91% accuracy. All of the profile variables except weight, MAP, and those related to inherent aerobic capacity (VO2max, percent body fat, resting heart rate) entered the risk equation for pre-bed-rest greyout. A cross-validation using 24 new subjects indicated a very stable model for risk prediction, accurate within 5% of the original equation. The result for the inherent fitness variables is significant in that a consensus as to whether an increased aerobic capacity is beneficial or detrimental has not been satisfactorily established. We conclude that tolerance to +Gz acceleration before and after simulated weightlessness is independent of inherent aerobic fitness. PMID:3689269

  7. Inherent Directionality Determines Spatial Release from Masking at the Tympanum in a Vertebrate with Internally Coupled Ears.

    PubMed

    Caldwell, Michael S; Lee, Norman; Bee, Mark A

    2016-08-01

    In contrast to humans and other mammals, many animals have internally coupled ears that function as inherently directional pressure-gradient receivers. Two important but unanswered questions are to what extent and how do animals with such ears exploit spatial cues in the perceptual analysis of noisy and complex acoustic scenes? This study of Cope's gray treefrog (Hyla chrysoscelis) investigated how the inherent directionality of internally coupled ears contributes to spatial release from masking. We used laser vibrometry and signal detection theory to determine the threshold signal-to-noise ratio at which the tympanum's response to vocalizations could be reliably detected in noise. Thresholds were determined as a function of signal location, noise location, and signal-noise separation. Vocalizations were broadcast from one of three azimuthal locations: frontal (0 °), to the right (+90 °), and to the left (-90 °). Masking noise was broadcast from each of 12 azimuthal angles around the frog (0 to 330 °, 30 ° separation). Variation in the position of the noise source resulted in, on average, 4 dB of spatial release from masking relative to co-located conditions. However, detection thresholds could be up to 9 dB lower in the "best ear for listening" compared to the other ear. The pattern and magnitude of spatial release from masking were well predicted by the tympanum's inherent directionality. We discuss how the magnitude of masking release observed in the tympanum's response to spatially separated signals and noise relates to that observed in previous behavioral and neurophysiological studies of frog hearing and communication. PMID:27125545

  8. Attentional bias toward safety predicts safety behaviors.

    PubMed

    Xu, Yaoshan; Li, Yongjuan; Wang, Guangxi; Yuan, Xiao; Ding, Weidong; Shen, Zhongxiang

    2014-10-01

    Safety studies have primarily focused on how explicit processes and measures affect safety behavior and subsequent accidents and injuries. Recently, safety researchers have paid greater attention to the role of implicit processes. Our research focuses on the role of attentional bias toward safety (ABS) in workplace safety. ABS is a basic, early-stage cognitive process involving the automatic and selective allocation of attentional resources toward safety cues, which reflect the implicit motivational state of employees regarding safety goal. In this study, we used two reaction time-based paradigms to measure the ABS of employees in three studies: two modified Stroop tasks (Studies 1 and 2) and a visual dot-probe task (Study 3). Results revealed that employees with better safety behavior showed significant ABS (Study 2), and greater ABS than employees with poorer safety behavior (Studies 1 and 2). Moreover, ABS was positively associated with the perceived safety climate and safety motivation of employees, both of which mediate the effect of ABS on safety behavior (Study 3). These results contributed to a deeper understanding of how early-stage automatic perceptual processing affects safety behavior. The practical implications of these results were also discussed. PMID:24922613

  9. Modular HTGR Safety Basis and Approach

    SciTech Connect

    Thomas Hicks

    2011-08-01

    The Next Generation Nuclear Plant (NGNP) will be a licensed commercial high temperature gas-cooled reactor (HTGR) capable of producing electricity and/or high temperature process heat for industrial markets supporting a range of end-user applications. The NGNP Project has adopted the 10 CFR 52 Combined License (COL) process, as recommended in the NGNP Licensing Strategy - A Report to Congress, dated August 2008, as the foundation for the NGNP licensing strategy [DOE/NRC 2008]. Nuclear Regulatory Commission (NRC) licensing of the NGNP plant utilizing this process will demonstrate the efficacy for licensing future HTGRs for commercial industrial applications. This information paper is one in a series of submittals that address key generic issues of the priority licensing topics as part of the process for establishing HTGR regulatory requirements. This information paper provides a summary level introduction to HTGR history, public safety objectives, inherent and passive safety features, radionuclide release barriers, functional safety approach, and risk-informed safety approach. The information in this paper is intended to further the understanding of the modular HTGR safety approach with the NRC staff and public stakeholders. The NGNP project does not expect to receive comments on this information paper because other white papers are addressing key generic issues of the priority licensing topics in greater detail.

  10. Colorimetric detection based on localised surface plasmon resonance of gold nanoparticles: Merits, inherent shortcomings and future prospects.

    PubMed

    Zhang, Yanlin; McKelvie, Ian D; Cattrall, Robert W; Kolev, Spas D

    2016-05-15

    Localised surface plasmon resonance (LSPR) of gold nanoparticles (AuNPs) has been exploited for two decades in analytical science and has proven to be a powerful tool for the detection of various kinds of substances including small molecules, ions, macro biomolecules and microbes. Detection can be performed by visual colour change observations, photometry or resonance light scattering. A wide range of applications have been studied in the areas of environmental, pharmaceutical and biological analysis and clinical diagnosis. In this article, some fundamental aspects and important applications involving LSPR of AuNPs are reviewed. Several inherent shortcomings of these techniques and possible strategies to circumvent them are discussed. PMID:26992537

  11. Workplace Safety and Health Topics: Safety & Prevention

    MedlinePlus

    ... message, please visit this page: About CDC.gov . Workplace Safety and Health Topics Industries & Occupations Hazards & Exposures Diseases & ... Pinterest Twitter YouTube NIOSH Homepage NIOSH A-Z Workplace Safety & Health Topics Publications and Products Programs Contact NIOSH ...

  12. Simulation and operation of the EBR-2 automatic control rod drive system

    NASA Astrophysics Data System (ADS)

    Lehto, W. K.; Larson, H. A.; Dean, E. M.; Christensen, L. J.

    An automatic control rod drive system (ACRDS) installed at EBR-II produces shaped power transients from 40% to full reactor power at a linear ramp rate of 4 MWt/s. A digital computer and modified control rod drive provides this capability. Simulation and analysis of ACRDS experiments establish the safety envelope for reactor transient operation. Tailored transients are required as part of USDOE operational reliability testing program for prototypic fast reactor fuel cladding breach behavior studies. After initial EBR-II driver fuel testing and system checkout, test subassemblies were subjected to both slow and fast transients. In addition, the ACRDS is used for steady state operation and will be qualified to control power ascent from initial critical to full power.

  13. Food safety.

    PubMed

    Borchers, Andrea; Teuber, Suzanne S; Keen, Carl L; Gershwin, M Eric

    2010-10-01

    Food can never be entirely safe. Food safety is threatened by numerous pathogens that cause a variety of foodborne diseases, algal toxins that cause mostly acute disease, and fungal toxins that may be acutely toxic but may also have chronic sequelae, such as teratogenic, immunotoxic, nephrotoxic, and estrogenic effects. Perhaps more worrisome, the industrial activities of the last century and more have resulted in massive increases in our exposure to toxic metals such as lead, cadmium, mercury, and arsenic, which now are present in the entire food chain and exhibit various toxicities. Industrial processes also released chemicals that, although banned a long time ago, persist in the environment and contaminate our food. These include organochlorine compounds, such as 1,1,1-trichloro-2,2-bis(p-chlorophenyl)ethane (dichlorodiphenyl dichloroethene) (DDT), other pesticides, dioxins, and dioxin-like compounds. DDT and its breakdown product dichlorophenyl dichloroethylene affect the developing male and female reproductive organs. In addition, there is increasing evidence that they exhibit neurodevelopmental toxicities in human infants and children. They share this characteristic with the dioxins and dioxin-like compounds. Other food contaminants can arise from the treatment of animals with veterinary drugs or the spraying of food crops, which may leave residues. Among the pesticides applied to food crops, the organophosphates have been the focus of much regulatory attention because there is growing evidence that they, too, affect the developing brain. Numerous chemical contaminants are formed during the processing and cooking of foods. Many of them are known or suspected carcinogens. Other food contaminants leach from the packaging or storage containers. Examples that have garnered increasing attention in recent years are phthalates, which have been shown to induce malformations in the male reproductive system in laboratory animals, and bisphenol A, which negatively

  14. COLD-SAT feasibility study safety analysis

    NASA Technical Reports Server (NTRS)

    Mchenry, Steven T.; Yost, James M.

    1991-01-01

    The Cryogenic On-orbit Liquid Depot-Storage, Acquisition, and Transfer (COLD-SAT) satellite presents some unique safety issues. The feasibility study conducted at NASA-Lewis desired a systems safety program that would be involved from the initial design in order to eliminate and/or control the inherent hazards. Because of this, a hazards analysis method was needed that: (1) identified issues that needed to be addressed for a feasibility assessment; and (2) identified all potential hazards that would need to be controlled and/or eliminated during the detailed design phases. The developed analysis method is presented as well as the results generated for the COLD-SAT system.

  15. Bromine Safety

    SciTech Connect

    Meyers, B

    2001-04-09

    The production and handling in 1999 of about 200 million kilograms of bromine plus substantial derivatives thereof by Great Lakes Chemical Corp. and Albemarle Corporation in their southern Arkansas refineries gave OSHA Occupational Injury/Illness Rates (OIIR) in the range of 0.74 to 1.60 reportable OIIRs per 200,000 man hours. OIIRs for similar industries and a wide selection of other U.S. industries range from 1.6 to 23.9 in the most recent OSHA report. Occupational fatalities for the two companies in 1999 were zero compared to a range in the U.S.of zero for all computer manufacturing to 0.0445 percent for all of agriculture, forestry and fishing in the most recent OSHA report. These results show that bromine and its compounds can be considered as safe chemicals as a result of the bromine safety standards and practices at the two companies. The use of hydrobromic acid as an electrical energy storage medium in reversible PEM fuel cells is discussed. A study in 1979 of 20 megawatt halogen working fluid power plants by Oronzio de Nora Group found such energy to cost 2 to 2.5 times the prevailing base rate at that time. New conditions may reduce this relative cost. The energy storage aspect allows energy delivery at maximum demand times where the energy commands premium rates. The study also found marginal cost and performance advantages for hydrobromic acid over hydrochloric acid working fluid. Separate studies in the late 70s by General Electric also showed marginal performance advantages for hydrobromic acid.

  16. Safety aspects of pneumatic transport. Information Circular/1985

    SciTech Connect

    Bowers, E.T.

    1985-01-01

    The work reported here deals with the safety aspects of pneumatic transport of underground coal, as well as the hazards inherent in more conventional haulage systems. Included are three designs for different applications of pneumatic haulage: off-loading a continuous-mining machine on a room-and-pillar section, vertical hoisting through a 1,200-ft shaft, and off-loading a tunnel-boring machine driving a 2,000-ft tunnel.

  17. Inherent variations in CO-H2S-mediated carotid body O2 sensing mediate hypertension and pulmonary edema.

    PubMed

    Peng, Ying-Jie; Makarenko, Vladislav V; Nanduri, Jayasri; Vasavda, Chirag; Raghuraman, Gayatri; Yuan, Guoxiang; Gadalla, Moataz M; Kumar, Ganesh K; Snyder, Solomon H; Prabhakar, Nanduri R

    2014-01-21

    Oxygen (O2) sensing by the carotid body and its chemosensory reflex is critical for homeostatic regulation of breathing and blood pressure. Humans and animals exhibit substantial interindividual variation in this chemosensory reflex response, with profound effects on cardiorespiratory functions. However, the underlying mechanisms are not known. Here, we report that inherent variations in carotid body O2 sensing by carbon monoxide (CO)-sensitive hydrogen sulfide (H2S) signaling contribute to reflex variation in three genetically distinct rat strains. Compared with Sprague-Dawley (SD) rats, Brown-Norway (BN) rats exhibit impaired carotid body O2 sensing and develop pulmonary edema as a consequence of poor ventilatory adaptation to hypobaric hypoxia. Spontaneous Hypertensive (SH) rat carotid bodies display inherent hypersensitivity to hypoxia and develop hypertension. BN rat carotid bodies have naturally higher CO and lower H2S levels than SD rat, whereas SH carotid bodies have reduced CO and greater H2S generation. Higher CO levels in BN rats were associated with higher substrate affinity of the enzyme heme oxygenase 2, whereas SH rats present lower substrate affinity and, thus, reduced CO generation. Reducing CO levels in BN rat carotid bodies increased H2S generation, restoring O2 sensing and preventing hypoxia-induced pulmonary edema. Increasing CO levels in SH carotid bodies reduced H2S generation, preventing hypersensitivity to hypoxia and controlling hypertension in SH rats. PMID:24395806

  18. The inherent dynamics of a molecular liquid: Geodesic pathways through the potential energy landscape of a liquid of linear molecules

    NASA Astrophysics Data System (ADS)

    Jacobson, Daniel; Stratt, Richard M.

    2014-05-01

    Because the geodesic pathways that a liquid follows through its potential energy landscape govern its slow, diffusive motion, we suggest that these pathways are logical candidates for the title of a liquid's "inherent dynamics." Like their namesake "inherent structures," these objects are simply features of the system's potential energy surface and thus provide views of the system's structural evolution unobstructed by thermal kinetic energy. This paper shows how these geodesic pathways can be computed for a liquid of linear molecules, allowing us to see precisely how such molecular liquids mix rotational and translational degrees of freedom into their dynamics. The ratio of translational to rotational components of the geodesic path lengths, for example, is significantly larger than would be expected on equipartition grounds, with a value that scales with the molecular aspect ratio. These and other features of the geodesics are consistent with a picture in which molecular reorientation adiabatically follows translation—molecules largely thread their way through narrow channels available in the potential energy landscape.

  19. Arrayed SU-8 polymer thermal actuators with inherent real-time feedback for actively modifying MEMS’ substrate warpage

    NASA Astrophysics Data System (ADS)

    Wang, Xinghua; Xiao, Dingbang; Chen, Zhihua; Wu, Xuezhong

    2016-09-01

    This paper describes the design, fabrication and characterization of a batch-fabricated micro-thermal actuators array with inherent real-time self-feedback, which can be used to actively modify micro-electro-mechanical systems’ (MEMS’) substrate warpage. Arrayed polymer thermal actuators utilize SU-8 polymer (a thick negative photoresist) as a functional material with integrated Ti/Al film-heaters as a microscale heat source. The electro-thermo-mechanical response of a micro-fabricated actuator was measured. The resistance of the Al/Ti film resistor varies obviously with ambient temperature, which can be used as inherent feedback for observing real-time displacement of activated SU-8 bumps (0.43 μm Ω‑1). Due to the high thermal expansion coefficient, SU-8 bumps tend to have relatively large deflection at low driving voltage and are very easily integrated with MEMS devices. Experimental results indicated that the proposed SU-8 polymer thermal actuators (array) are able to achieve accurate rectification of MEMS’ substrate warpage, which might find potential applications for solving stress-induced problems in MEMS.

  20. Nuclear criticality safety guide

    SciTech Connect

    Pruvost, N.L.; Paxton, H.C.

    1996-09-01

    This technical reference document cites information related to nuclear criticality safety principles, experience, and practice. The document also provides general guidance for criticality safety personnel and regulators.

  1. Farm Health and Safety

    MedlinePlus

    ... jobs in the United States. Farms have many health and safety hazards, including Chemicals and pesticides Machinery, ... equipment can also reduce accidents. Occupational Safety and Health Administration

  2. Medical Device Safety

    MedlinePlus

    ... Vaccines, Blood & Biologics Animal & Veterinary Cosmetics Tobacco Products Medical Devices Home Medical Devices Medical Device Safety Medical Device Safety Share Tweet Linkedin Pin it More sharing ...

  3. Health and safety impact of steam generator tube degradation

    SciTech Connect

    Marston T.

    1997-02-01

    In this paper the author addresses the problems inherent in evaluating the safety of steam generators with respect to tube rupture as part of a probabilistic safety analysis (PSA) of a reactor plant. He reviews the history of PSA as applied to reactors, and then looks at tube rupture histories as a start toward establishing event frequencies. He considers tube ruptures from the aspect of being an initiating event to being a conditional event to some other event, and then the question of performance of the steam generator in the face of a severe accident in the reactor.

  4. Inherent small telescope projects

    NASA Astrophysics Data System (ADS)

    Charles, P. A.

    2001-01-01

    As we stand on the verge of substantial access to the new generation of giant telescopes (Gemini, VLT and others) it is timely to consider the range of science that can be undertaken with the substantial number of smaller telescopes that are spread around the globe. While providing survey science input to the giant telescopes, or simultaneous monitoring capability for space missions, is a clearly important role (see previous contributions), it should not be forgotten that there are still many outstanding scientific programmes that can be undertaken on smaller telescopes in their own right. There is a danger of these opportunities being overlooked in the stampede to abandon the smaller telescope 'baggage' in the hope of acquiring access to more giant telescope time. I will try to demonstrate that the most effective and efficient use of all our telescope time requires access to a broad range of complementary facilities. I will therefore describe here some of the projects currently being undertaken with smaller telescopes as well as some of those planned for future facilities such as ROBONET.

  5. Failure and factors of safety in piping system design

    SciTech Connect

    Antaki, G.A.

    1993-01-01

    An important body of test and performance data on the behavior of piping systems has led to an ongoing reassessment of the code stress allowables and their safety margin. The codes stress allowables, and their factors of safety, are developed from limits on the incipient yield (for ductile materials), or incipient rupture (for brittle materials), of a test specimen loaded in simple tension. In this paper, we examine the failure theories introduced in the B31 and ASME III codes for piping and their inherent approximations compared to textbook failure theories. We summarize the evolution of factors of safety in ASME and B31 and point out that, for piping systems, it is appropriate to reconsider the concept and definition of factors of safety.

  6. Failure and factors of safety in piping system design

    SciTech Connect

    Antaki, G.A.

    1993-06-01

    An important body of test and performance data on the behavior of piping systems has led to an ongoing reassessment of the code stress allowables and their safety margin. The codes stress allowables, and their factors of safety, are developed from limits on the incipient yield (for ductile materials), or incipient rupture (for brittle materials), of a test specimen loaded in simple tension. In this paper, we examine the failure theories introduced in the B31 and ASME III codes for piping and their inherent approximations compared to textbook failure theories. We summarize the evolution of factors of safety in ASME and B31 and point out that, for piping systems, it is appropriate to reconsider the concept and definition of factors of safety.

  7. Achievements and challenges of Space Station Freedom's safety review process

    NASA Technical Reports Server (NTRS)

    Robinson, David W.

    1993-01-01

    The most complex space vehicle in history, Space Station Freedom, is well underway to completion, and System Safety is a vital part of the program. The purpose is to summarize and illustrate the progress that over one-hundred System Safety engineers have made in identifying, documenting, and controlling the hazards inherent in the space station. To date, Space Station Freedom has been reviewed by NASA's safety panels through the first six assembly flights, when Freedom achieves a configuration known as Man Tended Capability. During the eight weeks of safety reviews spread out over a year and a half, over 200 preliminary hazard reports were presented. Along the way NASA and its contractors faced many challenges, made much progress, and even learned a few lessons.

  8. Safety: An Attitude

    ERIC Educational Resources Information Center

    Smith, Harry T.

    1978-01-01

    Describes eight safety concepts developed by the author to teach safety and accident prevention in industrial arts shops and to promote more positive student attitudes toward shop safety. Stressing several general safety concepts instead of requiring dozens of rules has been found to work. (MF)

  9. Nuclear Powerplant Safety: Operations.

    ERIC Educational Resources Information Center

    Department of Energy, Washington, DC. Nuclear Energy Office.

    Powerplant systems and procedures that ensure the day-to-day health and safety of people in and around the plant is referred to as operational safety. This safety is the result of careful planning, good engineering and design, strict licensing and regulation, and environmental monitoring. Procedures that assure operational safety at nuclear…

  10. Modelling and characterization of thin film planar capacitors: inherent errors and limits of applicability of partial capacitance methods

    NASA Astrophysics Data System (ADS)

    Vukadinovic, M.; Malic, B.; Kosec, M.; Krizaj, D.

    2009-11-01

    The analytical partial capacitance methods (PCM) widely accepted for calculation of properties of capacitors with planar electrodes, coplanar strip waveguides (CPS) and coplanar waveguides (CPW) are reviewed based on the challenges met during the development and tailoring of (Ba, Sr)TiO3 thin films fabricated on different types of substrates. An alternative view on the conformal mapping method is given, a correction for electrodes of finite thickness is introduced and the applicability of easy-to-use simplified analytical equations is reviewed and extended. Calculation results obtained with different models are compared against the results of FEM numerical simulation in the parameter range relevant for development of tuneable ferroelectric films. The models were found to be less accurate than previously reported. Accordingly, guidelines for extending the applicability domain and for minimizing the inherent errors of the analytical models are presented. The discussion is focused on the possible improvements of the measurement techniques.

  11. Reinterpretation of velocity-dependent atomic friction: influence of the inherent instrumental noise in friction force microscopes.

    PubMed

    Dong, Yalin; Gao, Hongyu; Martini, Ashlie; Egberts, Philip

    2014-07-01

    We have applied both the master equation method and harmonic transition state theory to interpret the velocity-dependent friction behavior observed in atomic friction experiments. To understand the discrepancy between attempt frequencies measured in atomic force microscopy experiments and those estimated by theoretical models, both thermal noise and instrumental noise are introduced into the model. It is found that the experimentally observed low attempt frequency and the transition point at low velocity regimes can be interpreted in terms of the instrumental noise inherent in atomic force microscopy. In contrast to previous models, this model also predicts (1) the existence of a two-slope curve of velocity dependence and (2) the decrease of critical velocity with temperature, which provides clues for further experimental verification of the influence of instrumental noise in friction measurements. PMID:25122269

  12. Investigating mixel errors inherent in SSM/I data processed with the AES/York sea ice concentration algorithm

    SciTech Connect

    Sokol, J.L.; LeDrew, E.F.; Piwowar, J.M.

    1997-08-01

    Since 1972 passive microwave sensors have been used to monitor cryospheric variables due to their all weather imaging capabilities and near-global coverage. The low spatial resolution employed by passive sensors can result in mixer errors. Mixel errors are pixels contaminated with a mixture of land and water, occurring when the sensor passes over land cover transition areas. Special Sensor Microwave Imager (SSM/I) data from 1987-1994 was processed with the AES/York sea ice concentration algorithm and analyzed to investigate the interference which is inherent in data. In this investigation, the mixel phenomena was most evident in late summer images when the ice extent is at a minimum. After the shoreline had been dilated one pixel in width, an average of 77.8% of the mixel errors in the images are reduced. By identifying this major source of mixel errors in the sea ice concentration images, correction procedures can be developed to improve data accuracy.

  13. TDP-43 inclusion bodies formed in bacteria are structurally amorphous, non-amyloid and inherently toxic to neuroblastoma cells.

    PubMed

    Capitini, Claudia; Conti, Simona; Perni, Michele; Guidi, Francesca; Cascella, Roberta; De Poli, Angela; Penco, Amanda; Relini, Annalisa; Cecchi, Cristina; Chiti, Fabrizio

    2014-01-01

    Accumulation of ubiquitin-positive, tau- and α-synuclein-negative intracellular inclusions of TDP-43 in the central nervous system represents the major hallmark correlated to amyotrophic lateral sclerosis and frontotemporal lobar degeneration with ubiquitin-positive inclusions. Such inclusions have variably been described as amorphous aggregates or more structured deposits having an amyloid structure. Following the observations that bacterial inclusion bodies generally consist of amyloid aggregates, we have overexpressed full-length TDP-43 and C-terminal TDP-43 in E. coli, purified the resulting full-length and C-terminal TDP-43 containing inclusion bodies (FL and Ct TDP-43 IBs) and subjected them to biophysical analyses to assess their structure/morphology. We show that both FL and Ct TDP-43 aggregates contained in the bacterial IBs do not bind amyloid dyes such as thioflavin T and Congo red, possess a disordered secondary structure, as inferred using circular dichroism and infrared spectroscopies, and are susceptible to proteinase K digestion, thus possessing none of the hallmarks for amyloid. Moreover, atomic force microscopy revealed an irregular structure for both types of TDP-43 IBs and confirmed the absence of amyloid-like species after proteinase K treatment. Cell biology experiments showed that FL TDP-43 IBs were able to impair the viability of cultured neuroblastoma cells when added to their extracellular medium and, more markedly, when transfected into their cytosol, where they are at least in part ubiquitinated and phosphorylated. These data reveal an inherently high propensity of TDP-43 to form amorphous aggregates, which possess, however, an inherently high ability to cause cell dysfunction. This indicates that a gain of toxic function caused by TDP-43 deposits is effective in TDP-43 pathologies, in addition to possible loss of function mechanisms originating from the cellular mistrafficking of the protein. PMID:24497973

  14. [Effect of Inherent Immunity Factors of Development of Antibiotic Tolerance and Survival of Bacterial Populations under Antibiotic Attack].

    PubMed

    Demkina, E V; Loiko, N G; Mulyukin, A L; Smirnova, T A; Gaponov, A M; Pisarev, V M; Tutel'yan, A V; Nikolaev, Yu A; El'-Registan, G I

    2015-01-01

    Effect of human inherent immunity factors of, a gene-encoded antibacterial peptide indolicidin (Ind) and a cytokine interleukin 1 (IL1) on formation of antibiotic-tolerant persister cells surviving in the presence of ciprofloxacin (Cpf, 100 μg/mL) and ampicillin (Amp, 100 μg/mL) in submerged bacterial cultures (Staphylococcus aureus FGA 209P, Escherichia coli K12, and Pseudomonas aeruginosa PAO1) was studied. While Ind in physiological concentrations (0.3 and 3.0 μg/mL) introduced to the lag- or exponential-phase cultures of test organisms exhibited no reliable effect on population growth, the number of persisters increased at 3.0 μg/mL. Bactericidal Ind concentrations (9 μg/mL) suppressed S. aureus growth (-0.1% of surviving cells) with subsequent recovery due to development of the more antibiotic-tolerant white variant. Treatment with Cpf after Ind addition resulted in mutual potentiation of their antimicrobial activity, with the number of S. aureus persisters 2 to 3 orders of magnitude lower than in the case of the antibiotic alone. IL1, another immunity factor, when introduced (0.1-1 ng/mL) to the exponentially growing S. aureus culture (but not to the lag phase culture) had a temporary growth-static effect, with the number of persisters surviving Cpf treatment (100 μg/mL) increasing by 1 to 2 orders of magnitude. Electron microscopy revealed significant alterations in the outer cell envelope layer of surviving S. aureus cells, which should be associated with their changed antigenic properties. Thus, the factors of human inherent immunity have a dose-dependent effect on the growth of bacterial populations. In combination with antibiotics, they exhibit synergism of antimicrobial action (indolicidin) and minimize (indolicidin) or increase (interleukin 1) the frequency of formation of persister cells responsible for survival of a population subjected to an antibiotic attack. PMID:26964355

  15. TDP-43 Inclusion Bodies Formed in Bacteria Are Structurally Amorphous, Non-Amyloid and Inherently Toxic to Neuroblastoma Cells

    PubMed Central

    Capitini, Claudia; Conti, Simona; Perni, Michele; Guidi, Francesca; Cascella, Roberta; De Poli, Angela; Penco, Amanda; Relini, Annalisa; Cecchi, Cristina; Chiti, Fabrizio

    2014-01-01

    Accumulation of ubiquitin-positive, tau- and α-synuclein-negative intracellular inclusions of TDP-43 in the central nervous system represents the major hallmark correlated to amyotrophic lateral sclerosis and frontotemporal lobar degeneration with ubiquitin-positive inclusions. Such inclusions have variably been described as amorphous aggregates or more structured deposits having an amyloid structure. Following the observations that bacterial inclusion bodies generally consist of amyloid aggregates, we have overexpressed full-length TDP-43 and C-terminal TDP-43 in E. coli, purified the resulting full-length and C-terminal TDP-43 containing inclusion bodies (FL and Ct TDP-43 IBs) and subjected them to biophysical analyses to assess their structure/morphology. We show that both FL and Ct TDP-43 aggregates contained in the bacterial IBs do not bind amyloid dyes such as thioflavin T and Congo red, possess a disordered secondary structure, as inferred using circular dichroism and infrared spectroscopies, and are susceptible to proteinase K digestion, thus possessing none of the hallmarks for amyloid. Moreover, atomic force microscopy revealed an irregular structure for both types of TDP-43 IBs and confirmed the absence of amyloid-like species after proteinase K treatment. Cell biology experiments showed that FL TDP-43 IBs were able to impair the viability of cultured neuroblastoma cells when added to their extracellular medium and, more markedly, when transfected into their cytosol, where they are at least in part ubiquitinated and phosphorylated. These data reveal an inherently high propensity of TDP-43 to form amorphous aggregates, which possess, however, an inherently high ability to cause cell dysfunction. This indicates that a gain of toxic function caused by TDP-43 deposits is effective in TDP-43 pathologies, in addition to possible loss of function mechanisms originating from the cellular mistrafficking of the protein. PMID:24497973

  16. Modular High Temperature Gas-Cooled Reactor Safety Basis and Approach

    SciTech Connect

    David Petti; Jim Kinsey; Dave Alberstein

    2014-01-01

    Various international efforts are underway to assess the safety of advanced nuclear reactor designs. For example, the International Atomic Energy Agency has recently held its first Consultancy Meeting on a new cooperative research program on high temperature gas-cooled reactor (HTGR) safety. Furthermore, the Generation IV International Forum Reactor Safety Working Group has recently developed a methodology, called the Integrated Safety Assessment Methodology, for use in Generation IV advanced reactor technology development, design, and design review. A risk and safety assessment white paper is under development with respect to the Very High Temperature Reactor to pilot the Integrated Safety Assessment Methodology and to demonstrate its validity and feasibility. To support such efforts, this information paper on the modular HTGR safety basis and approach has been prepared. The paper provides a summary level introduction to HTGR history, public safety objectives, inherent and passive safety features, radionuclide release barriers, functional safety approach, and risk-informed safety approach. The information in this paper is intended to further the understanding of the modular HTGR safety approach. The paper gives those involved in the assessment of advanced reactor designs an opportunity to assess an advanced design that has already received extensive review by regulatory authorities and to judge the utility of recently proposed new methods for advanced reactor safety assessment such as the Integrated Safety Assessment Methodology.

  17. Launch Services Safety Overview

    NASA Technical Reports Server (NTRS)

    Loftin, Charles E.

    2008-01-01

    NASA/KSC Launch Services Division Safety (SA-D) services include: (1) Assessing the safety of the launch vehicle (2) Assessing the safety of NASA ELV spacecraft (S/C) / launch vehicle (LV) interfaces (3) Assessing the safety of spacecraft processing to ensure resource protection of: - KSC facilities - KSC VAFB facilities - KSC controlled property - Other NASA assets (4) NASA personnel safety (5) Interfacing with payload organizations to review spacecraft for adequate safety implementation and compliance for integrated activities (6) Assisting in the integration of safety activities between the payload, launch vehicle, and processing facilities

  18. Passive Safety Features for Small Modular Reactors

    SciTech Connect

    Ingersoll, Daniel T

    2010-01-01

    The rapid growth in the size and complexity of commercial nuclear power plants in the 1970s spawned an interest in smaller, simpler designs that are inherently or intrinsically safe through the use of passive design features. Several designs were developed, but none were ever built, although some of their passive safety features were incorporated into large commercial plant designs that are being planned or built today. In recent years, several reactor vendors are actively redeveloping small modular reactor (SMR) designs with even greater use of passive features. Several designs incorporate the ultimate in passive safety they completely eliminate specific accident initiators from the design. Other design features help to reduce the likelihood of an accident or help to mitigate the accident s consequences, should one occur. While some passive safety features are common to most SMR designs, irrespective of the coolant technology, other features are specific to water, gas, or liquid-metal cooled SMR designs. The extensive use of passive safety features in SMRs promise to make these plants highly robust, protecting both the general public and the owner/investor. Once demonstrated, these plants should allow nuclear power to be used confidently for a broader range of customers and applications than will be possible with large plants alone.

  19. [New initiatives to improve medication safety in hospitals].

    PubMed

    Otero López, María José

    2004-01-01

    Medication errors constitute a significant public health problem and are recognised as such nowadays among healthcare professionals, societies, authorities and international organizations. This has led to seeking and implementing effective practices focused on improving medication use safety. This article briefly describes some of the most recent initiatives promoted to prevent medication errors in the hospital setting. These safety improvement initiatives are based upon progressively developing an institutional culture of safety and on establishing practices designed to reduce errors or detect them in time, thus avoiding adverse effects to patients. Among these recent initiatives are the safety practices approved by the National Quality Forum, and the National Patient Safety Goals that the Joint Commission on Healthcare Accreditation has required since 2003. Also mentioned are several strategies that have been offered to facilitate the application of these practices, among which are the Pathways to Medication Safely, the development of collaborative projects among hospitals and organizations of experts, and the inclusion of a medication safety specialist in hospitals as a support figure overseeing the application of safety measures. Finally, the challenges inherent in putting these preventive measures into real patient's care are discussed. The barriers confronting this step must obviously be faced if improvements in patient safety are truly to be achieved. PMID:15293954

  20. TWRS safety program plan

    SciTech Connect

    Calderon, L.M., Westinghouse Hanford

    1996-08-01

    Management of Nuclear Safety, Industrial Safety, Industrial Hygiene, and Fire Protection programs, functions, and field support resources for Tank Waste Remediation Systems (TWRS) has, until recently, been centralized in TWRS Safety, under the Emergency, Safety, and Quality organization. Industrial hygiene technician services were also provided to support operational needs related to safety basis compliance. Due to WHC decentralization of safety and reengineering efforts in West Tank Farms, staffing and safety responsibilities have been transferred to the facilities. Under the new structure, safety personnel for TWRS are assigned directly to East Tank Farms, West Tank Farms, and a core Safety Group in TWRS Engineering. The Characterization Project Operations (CPO) safety organization will remain in tact as it currently exists. Personnel assigned to East Tank Farms, West Tank Farms, and CPO will perform facility-specific or project-specific duties and provide field implementation of programs. Those assigned to the core group will focus on activities having a TWRS-wide or programmatic focus. Hanford-wide activities will be the responsibility of the Safety Center of Expertise. In order to ensure an effective and consistent safety program for TWRS under the new organization program functions, goals, organizational structure, roles, responsibilities, and path forward must be clearly established. The purpose of the TWRS Safety Program Plan is to define the overall safety program, responsibilities, relationships, and communication linkages for safety personnel under the new structure. In addition, issues associated with reorganization transition are addressed, including training, project ownership, records management, and dissemination of equipment. For the purpose of this document ``TWRS Safety`` refers to all safety professionals and technicians (Industrial Safety, Industrial Hygiene, Fire Protection, and Nuclear Safety) within the TWRS organization, regardless of their

  1. Space engine safety system

    NASA Technical Reports Server (NTRS)

    Maul, William A.; Meyer, Claudia M.

    1991-01-01

    A rocket engine safety system is designed to initiate control procedures which will minimize damage to the engine and vehicle or test stand in the event of an engine failure. This report describes the features and the implementation issues associated with rocket engine safety systems. Specific concerns of safety systems applied to a space-based engine and long duration space missions are discussed. Examples of safety system features and architectures are given from recent safety monitoring investigations conducted for the Space Shuttle Main Engine and for future liquid rocket engines. Also, a general design and implementation process for rocket engine safety systems is presented.

  2. Space engine safety system

    NASA Technical Reports Server (NTRS)

    Maul, William A.; Meyer, Claudia M.

    1991-01-01

    A rocket engine safety system was designed to initiate control procedures to minimize damage to the engine or vehicle or test stand in the event of an engine failure. The features and the implementation issues associated with rocket engine safety systems are discussed, as well as the specific concerns of safety systems applied to a space-based engine and long duration space missions. Examples of safety system features and architectures are given, based on recent safety monitoring investigations conducted for the Space Shuttle Main Engine and for future liquid rocket engines. Also, the general design and implementation process for rocket engine safety systems is presented.

  3. Inherent predominance of high chiral angle metallic carbon nanotubes in continuous fibers grown from a molten catalyst.

    PubMed

    Alemán, B; Bernal, M Mar; Mas, B; Pérez, Emilio M; Reguero, V; Xu, G; Cui, Y; Vilatela, Juan J

    2016-02-21

    We present evidence that high temperature CVD growth of SWNTs under conditions of continuous spinning of macroscopic fibers leads to an inherent predominance of high chiral angle CNTs, peaking at the armchair end. Raman, UV-vis-NIR absorption, and photoluminescence spectroscopy measurements show the prevalence of metallic SWNTs. The complete chiral angle distribution is obtained by electron diffraction of over 390 CNTs. It is biased towards high chiral angles and peaks at the armchair end (30°), in good agreement with the established atomistic models for SWNT growth from a liquid catalyst. Based on the Fe-C-S constituent binary and ternary phase diagrams, thermodynamic calculations of phase compositions from fast cooling and experimental evidence of a post-synthesis catalyst, the proposed thermodynamic path of the catalyst is to form a solid FCC Fe core and a liquid Fe-S shell. S in the outer liquid shell first stabilizes the edge of the nascent CNT, but once a graphitic wall forms it is rejected due to the high interfacial energy of the Fe-C-S alloy. PMID:26837936

  4. Inherently mass-conservative version of the semi-Lagrangian Absolute Vorticity (SL-AV) atmospheric model dynamical core

    NASA Astrophysics Data System (ADS)

    Shashkin, V. V.; Tolstykh, M. A.

    2013-09-01

    The semi-Lagrangian Absolute Vorticity (SL-AV) atmospheric model is the global semi-Lagrangian hydrostatic model used for operational medium-range and seasonal forecasts at Hydrometeorological centre of Russia. The distinct feature of SL-AV dynamical core is the semi-implicit semi-Lagrangian vorticity-divergence formulation on the unstaggered grid. Semi-implicit semi-Lagrangian approach allows for long time steps while violates the global and local mass-conservation. In particular, the total mass in simulations with semi-Lagrangian models can drift significantly if no aposteriori mass-fixing algorithms are applied. However, the global mass-fixing algorithms degrade the local mass conservation. The inherently mass-conservative version of SL-AV model dynamical core presented in the article ensures global and local mass conservation without mass-fixing algorithms. The mass conservation is achieved with the introduction of the finite-volume semi-Lagrangian discretization for continuity equation based on the 3-D extension of the conservative cascade semi-Lagrangian transport scheme (CCS). The numerical experiments show that the presented new version of SL-AV dynamical core combines the accuracy and stability of the standard SL-AV dynamical core with the mass-conservation properties. The results of the mountain induced Rossby wave test and baroclinic instability test for mass-conservative dynamical core are found to be in agreement with the results available in literature.

  5. Inherently mass-conservative version of the semi-Lagrangian absolute vorticity (SL-AV) atmospheric model dynamical core

    NASA Astrophysics Data System (ADS)

    Shashkin, V. V.; Tolstykh, M. A.

    2014-02-01

    The semi-Lagrangian absolute vorticity (SL-AV) atmospheric model is the global semi-Lagrangian hydrostatic model used for operational medium-range and seasonal forecasts at the Hydrometeorological Centre of Russia. The distinct feature of the SL-AV dynamical core is the semi-implicit, semi-Lagrangian vorticity-divergence formulation on the unstaggered grid. A semi-implicit, semi-Lagrangian approach allows for long time steps but violates the global and local mass conservation. In particular, the total mass in simulations with semi-Lagrangian models can drift significantly if no a posteriori mass-fixing algorithm is applied. However, the global mass-fixing algorithms degrade the local mass conservation. The new inherently mass-conservative version of the SL-AV model dynamical core presented here ensures global and local mass conservation without mass-fixing algorithms. The mass conservation is achieved with the introduction of the finite-volume, semi-Lagrangian discretization for a continuity equation based on the 3-D extension of the conservative cascade semi-Lagrangian transport scheme (CCS). Numerical experiments show that the new version of the SL-AV dynamical core presented combines the accuracy and stability of the standard SL-AV dynamical core with the mass-conservation properties. The results of the mountain-induced Rossby-wave test and baroclinic instability test for the mass-conservative dynamical core are found to be in agreement with the results available in the literature.

  6. What drives selection on flowering time? An experimental manipulation of the inherent correlation between genotype and environment.

    PubMed

    Austen, Emily J; Weis, Arthur E

    2015-08-01

    The optimal timing of the seasonal switch from somatic growth to reproduction can depend on an individual's condition at reproduction, the quality of the environment in which it will reproduce, or both. In annual plants, vegetative size (a function of age at flowering) affects resources available for seed production, whereas exposure to mutualists, antagonists, and abiotic stresses in the environment (functions of Julian date of flowering) influences success in converting resources into offspring. The inherent tight correlation between age, size, and environment obscures their independent fitness contributions. We isolated the fitness effects of these factors by experimentally manipulating the correlation between age at flowering and date of flowering in Brassica rapa. We staggered the planting dates of families with differing ages at flowering to produce experimental populations in which age at flowering and date of flowering were positively, negatively, or uncorrelated. In all populations, plants with an early date of flowering produced more seed than those flowering late, regardless of age or size at flowering onset. The temporal environment was thus the principal driver of selection on flowering time, but its importance relative to that of age and size varied with the presence/absence of herbivores and seed predators. PMID:26102569

  7. Inherent Structure-Guided Multi-view Learning for Alzheimer’s Disease and Mild Cognitive Impairment Classification

    PubMed Central

    Liu, Mingxia; Zhang, Daoqiang

    2016-01-01

    Multi-atlas based morphometric pattern analysis has been recently proposed for the automatic diagnosis of Alzheimer’s disease (AD) and its early stage, i.e., mild cognitive impairment (MCI), where multi-view feature representations for subjects are generated by using multiple atlases. However, existing multi-atlas based methods usually assume that each class is represented by a specific type of data distribution (i.e., a single cluster), while the underlying distribution of data is actually a prior unknown. In this paper, we propose an inherent structure-guided multi-view leaning (ISML) method for AD/MCI classification. Specifically, we first extract multi-view features for subjects using multiple selected atlases, and then cluster subjects in the original classes into several sub-classes (i.e., clusters) in each atlas space. Then, we encode each subject with a new label vector, by considering both the original class labels and the coding vectors for those sub-classes, followed by a multi-task feature selection model in each of multi-atlas spaces. Finally, we learn multiple SVM classifiers based on the selected features, and fuse them together by an ensemble classification method. Experimental results on the Alzheimer’s Disease Neuroimaging Initiative (ADNI) database demonstrate that our method achieves better performance than several state-of-the-art methods in AD/MCI classification. PMID:27088137

  8. CD19 CAR immune pressure induces B-precursor acute lymphoblastic leukaemia lineage switch exposing inherent leukaemic plasticity

    PubMed Central

    Jacoby, Elad; Nguyen, Sang M.; Fountaine, Thomas J.; Welp, Kathryn; Gryder, Berkley; Qin, Haiying; Yang, Yinmeng; Chien, Christopher D.; Seif, Alix E.; Lei, Haiyan; Song, Young K.; Khan, Javed; Lee, Daniel W.; Mackall, Crystal L.; Gardner, Rebecca A.; Jensen, Michael C.; Shern, Jack F.; Fry, Terry J.

    2016-01-01

    Adoptive immunotherapy using chimeric antigen receptor (CAR) expressing T cells targeting the CD19 B lineage receptor has demonstrated marked success in relapsed pre-B-cell acute lymphoblastic leukaemia (ALL). Persisting CAR-T cells generate sustained pressure against CD19 that may drive unique mechanisms of resistance. Pre-B ALL originates from a committed pre-B cell or an earlier progenitor, with potential to reprogram into other hematopoietic lineages. Here we report changes in lineage markers including myeloid conversion in patients following CD19 CAR therapy. Using murine ALL models we study the long-term effects of CD19 CAR-T cells and demonstrate partial or complete lineage switch as a consistent mechanism of CAR resistance depending on the underlying genetic oncogenic driver. Deletion of Pax5 or Ebf1 recapitulates lineage reprogramming occurring during CD19 CAR pressure. Our findings establish lineage switch as a mechanism of CAR resistance exposing inherent plasticity in genetic subtypes of pre-B-cell ALL. PMID:27460500

  9. CD19 CAR immune pressure induces B-precursor acute lymphoblastic leukaemia lineage switch exposing inherent leukaemic plasticity.

    PubMed

    Jacoby, Elad; Nguyen, Sang M; Fountaine, Thomas J; Welp, Kathryn; Gryder, Berkley; Qin, Haiying; Yang, Yinmeng; Chien, Christopher D; Seif, Alix E; Lei, Haiyan; Song, Young K; Khan, Javed; Lee, Daniel W; Mackall, Crystal L; Gardner, Rebecca A; Jensen, Michael C; Shern, Jack F; Fry, Terry J

    2016-01-01

    Adoptive immunotherapy using chimeric antigen receptor (CAR) expressing T cells targeting the CD19 B lineage receptor has demonstrated marked success in relapsed pre-B-cell acute lymphoblastic leukaemia (ALL). Persisting CAR-T cells generate sustained pressure against CD19 that may drive unique mechanisms of resistance. Pre-B ALL originates from a committed pre-B cell or an earlier progenitor, with potential to reprogram into other hematopoietic lineages. Here we report changes in lineage markers including myeloid conversion in patients following CD19 CAR therapy. Using murine ALL models we study the long-term effects of CD19 CAR-T cells and demonstrate partial or complete lineage switch as a consistent mechanism of CAR resistance depending on the underlying genetic oncogenic driver. Deletion of Pax5 or Ebf1 recapitulates lineage reprogramming occurring during CD19 CAR pressure. Our findings establish lineage switch as a mechanism of CAR resistance exposing inherent plasticity in genetic subtypes of pre-B-cell ALL. PMID:27460500

  10. Field-induced networks of weak-links: an experimental demonstration that the paramagnetic Meissner effect is inherent to granularity

    NASA Astrophysics Data System (ADS)

    Ortiz, W. A.; Lisboa-Filho, P. N.; Passos, W. A. C.; Araújo-Moreira, F. M.

    2001-10-01

    In this article we report a direct observation that the paramagnetic Meissner effect (PME, also called Wohlleben effect), presented by some superconducting samples, is an inherent consequence of granularity in superconductors. The experiments reported here were performed using high-quality thin films of Nb and YBa 2Cu 3O 7- δ. A network of randomly distributed SS‧S weak-links was induced on the film by application of a small perpendicular DC magnetic field. The high demagnetization factor arising from this geometry, forces magnetic flux to penetrate into the sample, establishing a pattern of magnetic dendrites. By changing the external field we can adjust the critical current strength of the weak-links, thus controlling the magnetic response of the induced network. In this way we have tuned the temperature dependence of the field-cooled magnetization. An important conclusion supported by the experiments is that PME results from a competition between positive and negative magnetic responses generated by different levels of granularity in a multigranular system. This is in accordance with previous experiments correlating PME and the dynamic reentrance exhibited by a Josephson junction array, a particularly ordered granular system.

  11. Inherently-Forced Tensile Strain in Nanodiamond-Derived Onion-like Carbon: Consequences in Defect-Induced Electrochemical Activation.

    PubMed

    Ko, Young-Jin; Cho, Jung-Min; Kim, Inho; Jeong, Doo Seok; Lee, Kyeong-Seok; Park, Jong-Keuk; Baik, Young-Joon; Choi, Heon-Jin; Lee, Seung-Cheol; Lee, Wook-Seong

    2016-01-01

    We analyzed the nanodiamond-derived onion-like carbon (OLC) as function of synthesis temperature (1000~1400 °C), by high-resolution electron microscopy, electron energy loss spectroscopy, visible-Raman spectroscopy, ultraviolet photoemission spectroscopy, impedance spectroscopy, cyclic voltammetry and differential pulse voltammetry. The temperature dependences of the obtained properties (averaged particle size, tensile strain, defect density, density of states, electron transfer kinetics, and electrochemical oxidation current) unanimously coincided: they initially increased and saturated at 1200 °C. It was attributed to the inherent tensile strains arising from (1) the volume expansion associated with the layer-wise diamond-to-graphite transformation of the core, which caused forced dilation of the outer shells during their thermal synthesis; (2) the extreme curvature of the shells. The former origin was dominant over the latter at the outermost shell, of which the relevant evolution in defect density, DOS and electron transfer kinetics determined the electrochemical performances. In detection of dopamine (DA), uric acid (UA) and ascorbic acid (AA) using the OLC as electrode, their oxidation peak currents were enhanced by factors of 15~60 with annealing temperature. Their limit of detection and the linear range of detection, in the post-treatment-free condition, were as excellent as those of the nano-carbon electrodes post-treated by Pt-decoration, N-doping, plasma, or polymer. PMID:27032957

  12. Inherently-Forced Tensile Strain in Nanodiamond-Derived Onion-like Carbon: Consequences in Defect-Induced Electrochemical Activation

    NASA Astrophysics Data System (ADS)

    Ko, Young-Jin; Cho, Jung-Min; Kim, Inho; Jeong, Doo Seok; Lee, Kyeong-Seok; Park, Jong-Keuk; Baik, Young-Joon; Choi, Heon-Jin; Lee, Seung-Cheol; Lee, Wook-Seong

    2016-04-01

    We analyzed the nanodiamond-derived onion-like carbon (OLC) as function of synthesis temperature (1000~1400 °C), by high-resolution electron microscopy, electron energy loss spectroscopy, visible-Raman spectroscopy, ultraviolet photoemission spectroscopy, impedance spectroscopy, cyclic voltammetry and differential pulse voltammetry. The temperature dependences of the obtained properties (averaged particle size, tensile strain, defect density, density of states, electron transfer kinetics, and electrochemical oxidation current) unanimously coincided: they initially increased and saturated at 1200 °C. It was attributed to the inherent tensile strains arising from (1) the volume expansion associated with the layer-wise diamond-to-graphite transformation of the core, which caused forced dilation of the outer shells during their thermal synthesis; (2) the extreme curvature of the shells. The former origin was dominant over the latter at the outermost shell, of which the relevant evolution in defect density, DOS and electron transfer kinetics determined the electrochemical performances. In detection of dopamine (DA), uric acid (UA) and ascorbic acid (AA) using the OLC as electrode, their oxidation peak currents were enhanced by factors of 15~60 with annealing temperature. Their limit of detection and the linear range of detection, in the post-treatment-free condition, were as excellent as those of the nano-carbon electrodes post-treated by Pt-decoration, N-doping, plasma, or polymer.

  13. Development of ocean color algorithms for estimating chlorophyll-a concentrations and inherent optical properties using gene expression programming (GEP).

    PubMed

    Chang, Chih-Hua

    2015-03-01

    This paper proposes new inversion algorithms for the estimation of Chlorophyll-a concentration (Chla) and the ocean's inherent optical properties (IOPs) from the measurement of remote sensing reflectance (Rrs). With in situ data from the NASA bio-optical marine algorithm data set (NOMAD), inversion algorithms were developed by the novel gene expression programming (GEP) approach, which creates, manipulates and selects the most appropriate tree-structured functions based on evolutionary computing. The limitations and validity of the proposed algorithms are evaluated by simulated Rrs spectra with respect to NOMAD, and a closure test for IOPs obtained at a single reference wavelength. The application of GEP-derived algorithms is validated against in situ, synthetic and satellite match-up data sets compiled by NASA and the International Ocean Color Coordinate Group (IOCCG). The new algorithms are able to provide Chla and IOPs retrievals to those derived by other state-of-the-art regression approaches and obtained with the semi- and quasi-analytical algorithms, respectively. In practice, there are no significant differences between GEP, support vector regression, and multilayer perceptron model in terms of the overall performance. The GEP-derived algorithms are successfully applied in processing the images taken by the Sea Wide Field-of-view Sensor (SeaWiFS), generate Chla and IOPs maps which show better details of developing algal blooms, and give more information on the distribution of water constituents between different water bodies. PMID:25836776

  14. Inherently-Forced Tensile Strain in Nanodiamond-Derived Onion-like Carbon: Consequences in Defect-Induced Electrochemical Activation

    PubMed Central

    Ko, Young-Jin; Cho, Jung-Min; Kim, Inho; Jeong, Doo Seok; Lee, Kyeong-Seok; Park, Jong-Keuk; Baik, Young-Joon; Choi, Heon-Jin; Lee, Seung-Cheol; Lee, Wook-Seong

    2016-01-01

    We analyzed the nanodiamond-derived onion-like carbon (OLC) as function of synthesis temperature (1000~1400 °C), by high-resolution electron microscopy, electron energy loss spectroscopy, visible-Raman spectroscopy, ultraviolet photoemission spectroscopy, impedance spectroscopy, cyclic voltammetry and differential pulse voltammetry. The temperature dependences of the obtained properties (averaged particle size, tensile strain, defect density, density of states, electron transfer kinetics, and electrochemical oxidation current) unanimously coincided: they initially increased and saturated at 1200 °C. It was attributed to the inherent tensile strains arising from (1) the volume expansion associated with the layer-wise diamond-to-graphite transformation of the core, which caused forced dilation of the outer shells during their thermal synthesis; (2) the extreme curvature of the shells. The former origin was dominant over the latter at the outermost shell, of which the relevant evolution in defect density, DOS and electron transfer kinetics determined the electrochemical performances. In detection of dopamine (DA), uric acid (UA) and ascorbic acid (AA) using the OLC as electrode, their oxidation peak currents were enhanced by factors of 15~60 with annealing temperature. Their limit of detection and the linear range of detection, in the post-treatment-free condition, were as excellent as those of the nano-carbon electrodes post-treated by Pt-decoration, N-doping, plasma, or polymer. PMID:27032957

  15. Validation of satellite-retrieved oceanic inherent optical properties: proposed two-color elastic backscatter lidar and retrieval theory

    NASA Astrophysics Data System (ADS)

    Hoge, Frank E.

    2003-12-01

    Recent radiative transfer models show that: (1) regardless of elastic lidar receiver field of view (FOV), at vanishing lidar depth the lidar-derived attenuation coefficient klidar --> a, where a is the total absorption coefficient per meter of depth; and (2) for a wide FOV as the lidar sensing depth approaches some large value (depending on water type), klidar --> Kd, where Kd is the diffuse attenuation for downwelling irradiance. As a result, it is shown that a time-resolved, dual-wavelength-laser, elastic-backscattering lidar can retrieve the three principal oceanic optical properties: (1) the absorption coefficient of phytoplankton aph, (2) the absorption coefficient of chromophoric dissolved organic matter (CDOM) aCDOM, and (3) the nonwater total constituent backscattering coefficient bbt. The lidar-retrieved aph, aCDOM, and bbt inherent optical properties can be used to validate corresponding satellite-derived products such as those from terra moderate-resolution imaging spectroradiometer (MODIS), Aqua MODIS, Sea-viewing Wide Field-of-view Sensor, (SeaWiFS), and other ocean color sensors.

  16. Vocational Education Safety Instruction Manual.

    ERIC Educational Resources Information Center

    Cropley, Russell, Ed.; Doherty, Susan Sloan, Ed.

    This manual describes four program areas in vocational education safety instruction: (1) introduction to a safety program; (2) resources to ensure laboratory safety; (3) safety program implementation; and (4) safety rules and safety tests. The safety rules and tests included in section four are for the most common tools and machines used in…

  17. Medicine safety and children

    MedlinePlus

    ... this page: //medlineplus.gov/ency/patientinstructions/000619.htm Medicine safety and children To use the sharing features ... especially careful if you have toddlers around. Keep Medicines out of Reach and Sight Safety tips: DO ...

  18. Water safety and drowning

    MedlinePlus

    ... among people of all ages. Learning and practicing water safety is important to prevent drowning accidents. ... Water safety tips for all ages include: Learn CPR Never swim alone Never dive into water unless ...

  19. Safety organizations and experts

    NASA Technical Reports Server (NTRS)

    Mandel, G.; Rubinstein, R. I.; Pinto, J. J.; Meschkow, S. Z.

    1977-01-01

    Handbook lists organizations and experts in specific, well defined areas of safety technology. Special emphasis is given to relevant safety information sources on aircraft fire hazards and aircraft interior flammability.

  20. Motor Vehicle Safety

    MedlinePlus

    ... these crashes is one part of motor vehicle safety. Here are some things you can do to ... speed or drive aggressively Don't drive impaired Safety also involves being aware of others. Share the ...

  1. Farm Health and Safety

    MedlinePlus

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

  2. Safety in Science Laboratories.

    ERIC Educational Resources Information Center

    Education in Science, 1978

    1978-01-01

    Presents 12 amendments to the second edition of Safety in Science Laboratories. Covers topics such as regular inspection of equipment, wearing safety glasses, dating stock chemicals, and safe use of chemicals. (MA)

  3. Security vs. Safety.

    ERIC Educational Resources Information Center

    Sturgeon, Julie

    1999-01-01

    Provides administrative advice on how some safety experts have made college campuses safer and friendlier without breaking the budget. Tips on security and advice on safety management that encompasses the whole environment are highlighted. (GR)

  4. Facility safety study

    NASA Technical Reports Server (NTRS)

    1979-01-01

    The safety of NASA's in house microelectronics facility is addressed. Industrial health standards, facility emission control requirements, operation and safety checklists, and the disposal of epitaxial vent gas are considered.

  5. Spacecraft Fire Safety

    NASA Technical Reports Server (NTRS)

    Margle, Janice M. (Editor)

    1987-01-01

    Fire detection, fire standards and testing, fire extinguishment, inerting and atmospheres, fire-related medical science, aircraft fire safety, Space Station safety concerns, microgravity combustion, spacecraft material flammability testing, and metal combustion are among the topics considered.

  6. The Evolution of Process Safety: Current Status and Future Direction.

    PubMed

    Mannan, M Sam; Reyes-Valdes, Olga; Jain, Prerna; Tamim, Nafiz; Ahammad, Monir

    2016-06-01

    The advent of the industrial revolution in the nineteenth century increased the volume and variety of manufactured goods and enriched the quality of life for society as a whole. However, industrialization was also accompanied by new manufacturing and complex processes that brought about the use of hazardous chemicals and difficult-to-control operating conditions. Moreover, human-process-equipment interaction plus on-the-job learning resulted in further undesirable outcomes and associated consequences. These problems gave rise to many catastrophic process safety incidents that resulted in thousands of fatalities and injuries, losses of property, and environmental damages. These events led eventually to the necessity for a gradual development of a new multidisciplinary field, referred to as process safety. From its inception in the early 1970s to the current state of the art, process safety has come to represent a wide array of issues, including safety culture, process safety management systems, process safety engineering, loss prevention, risk assessment, risk management, and inherently safer technology. Governments and academic/research organizations have kept pace with regulatory programs and research initiatives, respectively. Understanding how major incidents impact regulations and contribute to industrial and academic technology development provides a firm foundation to address new challenges, and to continue applying science and engineering to develop and implement programs to keep hazardous materials within containment. Here the most significant incidents in terms of their impact on regulations and the overall development of the field of process safety are described. PMID:26979411

  7. Electrical safety guidelines

    SciTech Connect

    Not Available

    1993-09-01

    The Electrical Safety Guidelines prescribes the DOE safety standards for DOE field offices or facilities involved in the use of electrical energy. It has been prepared to provide a uniform set of electrical safety standards and guidance for DOE installations in order to affect a reduction or elimination of risks associated with the use of electrical energy. The objectives of these guidelines are to enhance electrical safety awareness and mitigate electrical hazards to employees, the public, and the environment.

  8. Safety analysts training

    SciTech Connect

    Bolton, P.

    2000-10-01

    The purpose of this task was to support ESH-3 in providing Airborne Release Fraction and Respirable Fraction training to safety analysts at LANL who perform accident analysis, hazard analysis, safety analysis, and/or risk assessments at nuclear facilities. The task included preparation of materials for and the conduct of two 3-day training courses covering the following topics: safety analysis process; calculation model; aerosol physic concepts for safety analysis; and overview of empirically derived airborne release fractions and respirable fractions.

  9. DOE handbook electrical safety

    SciTech Connect

    1998-01-01

    Electrical Safety Handbook presents the Department of Energy (DOE) safety standards for DOE field offices or facilities involved in the use of electrical energy. It has been prepared to provide a uniform set of electrical safety guidance and information for DOE installations to effect a reduction or elimination of risks associated with the use of electrical energy. The objectives of this handbook are to enhance electrical safety awareness and mitigate electrical hazards to employees, the public, and the environment.

  10. Radiation Safety Compliance.

    PubMed

    Koth, Jana; Smith, Marcia Hess

    2016-05-01

    This article discusses radiation safety programs, including the members of the radiation safety team, their roles, and the challenges they face, with a focus on the radiation safety officer's duties. Agencies that regulate radiation safety also are described. The importance of minimizing patient dose, ensuring that dosimetry badges are worn correctly, and using therapeutic radioactive materials safely are addressed. Finally, radiologic technologists' role in using radiation safely is discussed, and the principles of time, distance, and shielding are reviewed. PMID:27146175

  11. Generic safety documentation model

    SciTech Connect

    Mahn, J.A.

    1994-04-01

    This document is intended to be a resource for preparers of safety documentation for Sandia National Laboratories, New Mexico facilities. It provides standardized discussions of some topics that are generic to most, if not all, Sandia/NM facilities safety documents. The material provides a ``core`` upon which to develop facility-specific safety documentation. The use of the information in this document will reduce the cost of safety document preparation and improve consistency of information.

  12. Aviation Safety Issues Database

    NASA Technical Reports Server (NTRS)

    Morello, Samuel A.; Ricks, Wendell R.

    2009-01-01

    The aviation safety issues database was instrumental in the refinement and substantiation of the National Aviation Safety Strategic Plan (NASSP). The issues database is a comprehensive set of issues from an extremely broad base of aviation functions, personnel, and vehicle categories, both nationally and internationally. Several aviation safety stakeholders such as the Commercial Aviation Safety Team (CAST) have already used the database. This broader interest was the genesis to making the database publically accessible and writing this report.

  13. HSE's safety assessment principles for criticality safety.

    PubMed

    Simister, D N; Finnerty, M D; Warburton, S J; Thomas, E A; Macphail, M R

    2008-06-01

    The Health and Safety Executive (HSE) published its revised Safety Assessment Principles for Nuclear Facilities (SAPs) in December 2006. The SAPs are primarily intended for use by HSE's inspectors when judging the adequacy of safety cases for nuclear facilities. The revised SAPs relate to all aspects of safety in nuclear facilities including the technical discipline of criticality safety. The purpose of this paper is to set out for the benefit of a wider audience some of the thinking behind the final published words and to provide an insight into the development of UK regulatory guidance. The paper notes that it is HSE's intention that the Safety Assessment Principles should be viewed as a reflection of good practice in the context of interpreting primary legislation such as the requirements under site licence conditions for arrangements for producing an adequate safety case and for producing a suitable and sufficient risk assessment under the Ionising Radiations Regulations 1999 (SI1999/3232 www.opsi.gov.uk/si/si1999/uksi_19993232_en.pdf). PMID:18495990

  14. An Innovative Hybrid Loop-Pool SFR Design and Safety Analysis Methods: Today and Tomorrow

    SciTech Connect

    Hongbin Zhang; Haihua Zhao; Vincent Mousseau

    2008-04-01

    Investment in commercial sodium cooled fast reactor (SFR) power plants will become possible only if SFRs achieve economic competitiveness as compared to light water reactors and other Generation IV reactors. Toward that end, we have launched efforts to improve the economics and safety of SFRs from the thermal design and safety analyses perspectives at Idaho National Laboratory. From the thermal design perspective, an innovative hybrid loop-pool SFR design has been proposed. This design takes advantage of the inherent safety of a pool design and the compactness of a loop design to further improve economics and safety. From the safety analyses perspective, we have initiated an effort to develop a high fidelity reactor system safety code.

  15. Major Energy Efficiency Opportunities in Laboratories --Implications for Health and Safety

    SciTech Connect

    Mathew, Paul A.; Sartor, Dale A.; Bell, Geoffrey C.; Drummond,David

    2007-04-27

    Laboratory facilities present a unique challenge for energy efficient design, partly due to their health and safety requirements. Recent experience has shown that there is significant energy efficiency potential in laboratory buildings. However, there is often a misperception in the laboratory community that energy efficiency will inherently compromise safety. In some cases, energy efficiency measures require special provisions to ensure that safety requirements are met. In other cases, efficiency measures actually improve safety. In this paper we present five major, yet under-utilized, energy efficiency strategies for ventilation-intensive laboratories and discuss their implications for health and safety. These include: (a) optimizing ventilation rates; (b) reducing laboratory chemical hood energy use; (c) low-pressure drop HVAC design; (d) right-sizing HVAC systems; and (e) reducing simultaneous heating and cooling. In all cases, the successful design and implementation of these strategies requires active and informed participation by health and safety personnel.

  16. Virtual Safety Training.

    ERIC Educational Resources Information Center

    Fuller, Scott; Davis, Jason

    2003-01-01

    The Multimedia Tool Box Talk is a web-based quick reference safety guide and training tool for construction personnel. An intended outcome of this effort was to provide an efficient and effective way to locate and interpret crucial safety information while at the job site. The tool includes information from the Occupational Safety and Health…

  17. School Safety Audit Protocol.

    ERIC Educational Resources Information Center

    DeMary, Jo Lynne; Owens, Marsha; Ramnarain, A. K. Vijay

    The 1997 Virginia General Assembly passed legislation directing school boards to require all schools to conduct safety audits. This audit is designed to assess the safety conditions in each public school to: (1) identify and, if necessary, develop solutions for physical safety concerns, including building security issues; and (2) identify and…

  18. Safety in the Preschool.

    ERIC Educational Resources Information Center

    Settles, Mimi

    Guidelines for safety in the cooperative preschool are outlined, emphasizing control of the physical environment to insure maximum freedom for the children compatible with maximum safety. Building standards are set for stairways, rooms, lavatories, parking lots, harmful supplies, and wading pools. Orientation for safety is discussed in regard to…

  19. Revitalizing Nuclear Safety Research.

    ERIC Educational Resources Information Center

    National Academy of Sciences - National Research Council, Washington, DC.

    This report covers the general issues involved in nuclear safety research and points out the areas needing detailed consideration. Topics included are: (1) "Principles of Nuclear Safety Research" (examining who should fund, who should conduct, and who should set the agenda for nuclear safety research); (2) "Elements of a Future Agenda for Nuclear…

  20. School Bus Safety.

    ERIC Educational Resources Information Center

    Stroup, Karen Bruner; And Others

    1991-01-01

    Equipment to allow safe transportation of disabled children is reviewed. Such equipment includes infant car seats, child safety seats, safety vests, and accommodations for children in casts and/or braces. Five principles for evaluation and selection of safe seating options are given as are safety rules and information on standards and resources.…

  1. SNTP environmental, safety, and health

    NASA Technical Reports Server (NTRS)

    Harmon, Charles D.

    1993-01-01

    Viewgraphs on space nuclear thermal propulsion (SNTP) environmental, safety, and health are presented. Topics covered include: program safety policy; program safety policies; and DEIS public hearing comments.

  2. Enhancing the safety of tailings management facilities

    SciTech Connect

    Meggyes, T.; Niederleithinger, E.; Witt, K.J.; Csovari, M.; Kreft-Burman, K.; Engels, J.; McDonald, C.; Roehl, K.E.

    2008-07-01

    Unsafe tailings management facilities (TMFs) have caused serious accidents in Europe threatening human health/life and the environment. While advanced design, construction and management procedures are available, their implementation requires greater emphasis. An integrated research project funded by the European Union was carried out between 2002 and 2005 with the overall goal of improving the safety of TMFs (Sustainable Improvement in Safety of Tailings Facilities - TAILSAFE, http://www.tailsafe.com/). The objective of TAILSAFE was to develop and apply methods of parameter evaluation and measurement for the assessment and improvement of the safety state of tailings facilities, with particular attention to the stability of tailings dams and slurries, the special risks inherent when such materials include toxic or hazardous wastes, and authorization and management procedures for tailings facilities. Aspects of tailings facilities design, water management and slurry transport, non-destructive and minimally intrusive testing methods, monitoring and the application of sensors, intervention and remediation options were considered in TAILSAFE. A risk reduction framework (the TAILSAFE Parameter Framework) was established to contribute to the avoidance of catastrophic accidents and hazards from tailings facilities. Tailings from the mining and primary processing of metals, minerals and coal were included within the scope of TAILSAFE. The project focused on the avoidance of hazards by developing procedures and methods for investigating and improving the stability of tailings dams and tailings bodies.

  3. Health-related safety: a framework to address barriers to aging in place.

    PubMed

    Lau, Denys T; Scandrett, Karen Glasser; Jarzebowski, Mary; Holman, Kami; Emanuel, Linda

    2007-12-01

    Maintaining safety in the home and community is a national public health concern, especially for older adults who "age in place." In this article, we introduce a multicausal concept called "health-related safety," which is defined as the minimization of the probability of preventable, unintended harm in community-dwelling individuals. Derived from the modern patient safety movement, health-related safety attributes adverse health events in the home and community to systematic breakdowns in the societal system, not to the commission of errors by particular individuals. Extending beyond health care institutions, the health-related safety framework is composed of multiple levels: micro (consumers and providers); mezzo (homes and communities); and macro (policies). Because the societal system is complex with inherent risks, health-related safety will require a culture shift and system redesign, new tools of risk assessments and management, and continuous safety improvement. We propose a research agenda to further refine the health-related safety framework by using empirical evidence and to develop appropriate mathematical and practical models from safety sciences to support this initiative. This article moves the field forward by applying systems thinking and safety sciences to health-related safety in the home and community, thereby paralleling what researchers have begun to do with patient safety in health care systems. PMID:18192636

  4. Emotion regulation during threat: Parsing the time course and consequences of safety signal processing.

    PubMed

    Hefner, Kathryn R; Verona, Edelyn; Curtin, John J

    2016-08-01

    Improved understanding of fear inhibition processes can inform the etiology and treatment of anxiety disorders. Safety signals can reduce fear to threat, but precise mechanisms remain unclear. Safety signals may acquire attentional salience and affective properties (e.g., relief) independent of the threat; alternatively, safety signals may only hold affective value in the presence of simultaneous threat. To clarify such mechanisms, an experimental paradigm assessed independent processing of threat and safety cues. Participants viewed a series of red and green words from two semantic categories. Shocks were administered following red words (cue+). No shocks followed green words (cue-). Words from one category were defined as safety signals (SS); no shocks were administered on cue+ trials. Words from the other (control) category did not provide information regarding shock administration. Threat (cue+ vs. cue-) and safety (SS+ vs. SS-) were fully crossed. Startle response and ERPs were recorded. Startle response was increased during cue+ versus cue-. Safety signals reduced startle response during cue+, but had no effect on startle response during cue-. ERP analyses (PD130 and P3) suggested that participants parsed threat and safety signal information in parallel. Motivated attention was not associated with safety signals in the absence of threat. Overall, these results confirm that fear can be reduced by safety signals. Furthermore, safety signals do not appear to hold inherent hedonic salience independent of their effect during threat. Instead, safety signals appear to enable participants to engage in effective top-down emotion regulatory processes. PMID:27088643

  5. Safety philosophy of gas turbine high temperature reactor (GTHTR300)

    SciTech Connect

    Shoji Katanishi; Kazuhiko Kunitomi; Shusaku Shiozawa

    2002-07-01

    Japan Atomic Energy Research Institute (JAERI) has undertaken the study of an original design concept of gas turbine high temperature reactor, the GTHTR300. The general concept of this study is development of a greatly simplified design that leads to substantially reduced technical and cost requirements. Newly proposed design features enable the GTHTR300 to be an efficient and economically competitive reactor in 2010's. Also, the GTHTR300 fully takes advantage of its inherent safety characteristics. The safety philosophy of the GTHTR300 is developed based on the HTTR (High Temperature Engineering Test Reactor) of JAERI which is the first HTGR in Japan. Major features of the newly proposed safety philosophy for the GTHTR300 are described in this article. (authors)

  6. Inherent predominance of high chiral angle metallic carbon nanotubes in continuous fibers grown from a molten catalyst

    NASA Astrophysics Data System (ADS)

    Alemán, B.; Bernal, M. Mar; Mas, B.; Pérez, Emilio M.; Reguero, V.; Xu, G.; Cui, Y.; Vilatela, Juan J.

    2016-02-01

    We present evidence that high temperature CVD growth of SWNTs under conditions of continuous spinning of macroscopic fibers leads to an inherent predominance of high chiral angle CNTs, peaking at the armchair end. Raman, UV-vis-NIR absorption, and photoluminescence spectroscopy measurements show the prevalence of metallic SWNTs. The complete chiral angle distribution is obtained by electron diffraction of over 390 CNTs. It is biased towards high chiral angles and peaks at the armchair end (30°), in good agreement with the established atomistic models for SWNT growth from a liquid catalyst. Based on the Fe-C-S constituent binary and ternary phase diagrams, thermodynamic calculations of phase compositions from fast cooling and experimental evidence of a post-synthesis catalyst, the proposed thermodynamic path of the catalyst is to form a solid FCC Fe core and a liquid Fe-S shell. S in the outer liquid shell first stabilizes the edge of the nascent CNT, but once a graphitic wall forms it is rejected due to the high interfacial energy of the Fe-C-S alloy.We present evidence that high temperature CVD growth of SWNTs under conditions of continuous spinning of macroscopic fibers leads to an inherent predominance of high chiral angle CNTs, peaking at the armchair end. Raman, UV-vis-NIR absorption, and photoluminescence spectroscopy measurements show the prevalence of metallic SWNTs. The complete chiral angle distribution is obtained by electron diffraction of over 390 CNTs. It is biased towards high chiral angles and peaks at the armchair end (30°), in good agreement with the established atomistic models for SWNT growth from a liquid catalyst. Based on the Fe-C-S constituent binary and ternary phase diagrams, thermodynamic calculations of phase compositions from fast cooling and experimental evidence of a post-synthesis catalyst, the proposed thermodynamic path of the catalyst is to form a solid FCC Fe core and a liquid Fe-S shell. S in the outer liquid shell first

  7. Safety after cardiac catheterization.

    PubMed

    Huber, Charlotte

    2009-08-01

    The Pennsylvania Patient Safety Authority's reporting system is a confidential, statewide Internet reporting system to which all Pennsylvania hospitals, outpatient-surgery facilities, and birthing centers, as well as some abortion facilities, must file information on medical errors. Safety Monitor is a column from the authority that informs nurses on issues that can affect patient safety and presents strategies they can easily integrate into practice. For more information on the authority, visit www.patientsafetyauthority.org. For the original article discussed in this column or for other articles on patient safety, click on "Patient Safety Advisories" and then "Advisory Library" in the left-hand navigation menu. PMID:19641415

  8. Carbon cycling in the upper waters of the Sargasso Sea: II. Numerical simulation of apparent and inherent optical properties

    NASA Astrophysics Data System (ADS)

    Bissett, W. P.; Carder, K. L.; Walsh, J. J.; Dieterle, D. A.

    1999-02-01

    A mathematical framework to incorporate spectral apparent and inherent optical properties into a one-dimensional ecological simulation (EcoSim) of the Sargasso Sea is developed. The simulation includes equations for spectral algal particulate absorption, in the form of 4 functional groups of phytoplankton, colored degradational matter (CDM), in the form of 2 classes of colored dissolved organic carbon (CDOC), and downwelling diffuse attenuation coefficients ( K d's) at a 5 nm resolution. Particulate absorption responds to changes in phytoplankton species biomass, pigmentation, and photo-adaptation. CDM absorption responds to concentration changes of labile and relict CDOC. K d's respond to changes in spectral total absorption, backscattering, and the average cosine of downwelling photons. The spectral bio-optical outputs provide an additional means of validating an ecological simulation. The vertical and seasonal changes in the diffuse attenuation coefficient at wavelengths of 412, 442, 467, 487, 522, and 567 nm compare well with in situ measurements. There appears to be an underestimation of CDM by the EcoSim that is reflected in the simulated absorption and attenuation at 412 nm. The particulate absorption slope between 412 and 487 nm suggests an overestimation of chlorophyll b and photoprotective carotenoid concentrations from Prochlorococcus functional groups. Simulated K d(522) and K d(567) appear to be higher than observations and may result from the exclusion of the inelastic scattering process (i.e. Raman scattering and CDM fluorescence). Results suggest that CDM absorption does not co-vary with particulate absorption. Comparison with a six year time-series of CZCS data suggests that CDM interference of the estimated CZCS chlorophyll a may have been pre-valent in the late spring and the early fall.

  9. A theoretical derivation of the dependence of the remotely sensed reflectance of the ocean on the inherent optical properties

    NASA Technical Reports Server (NTRS)

    Zaneveld, J. Ronald V.

    1995-01-01

    An expression for the ratio of the upwelling nadir radiance L(pi, z) and the downwelling scalar irradiance E(sub od)(Z) is derived from the following equation of radiative transfer. This expression is given by RSR(z) = (L(pi, z))/E(sub od) = (f(sub b)(z)b(sub b)(z))/2 pi(k(pi, z) + c(z) - F(sub L)(z)b(sub f)(z)), where b(sub b)(z) is the backscattering coefficient, k(pi, z) is the vertical attenuation coefficient of the nadir radiance, c(z) is the beam attenuation coefficient, and f(sub b)(z) and f(sub L)(z) are shape parameters that depend on the shape of the volume scattering function and the radiance distribution. Successive approximations are subsequently applied to the above exact equation. These are f(sub b)(z) = (2 pi beta(pi - theta(sub m), z)/(b(sub b)(z))), where beta(pi - theta(sub m), z) is the volume scattering function at 180 deg minus the zenith angle of the maximum radiance, and k(pi, z) = am = c(1 - 0.52 b/c - 0.44 (b/c)(exp 2)), where m is a parameter that is numerically equal to the inverse of the average cosine of the asymptotic light field for a medium with the same inherent optical properties, a is the absorption coefficient, and b/c is the single scattering albedo. Together with f(sub L)(z) = 1.05 and application of Gershun's equation, it is shown that for nearly all oceanic cases RSR(z) identical to L(pi, z)/E(sub od)(z) = (Beta(pi - theta(sub m), z))/(a(z)(1 + m(z))).

  10. Structure of Leishmania donovani coronin coiled coil domain reveals an antiparallel 4 helix bundle with inherent asymmetry.

    PubMed

    Nayak, Ashok Ranjan; Karade, Sharanbasappa Shrimant; Srivastava, Vijay Kumar; Rana, Ajay Kumar; Gupta, C M; Sahasrabuddhe, Amogh A; Pratap, J Venkatesh

    2016-07-01

    Coiled coils are ubiquitous structural motifs that serve as a platform for protein-protein interactions and play a central role in myriad physiological processes. Though the formation of a coiled coil requires only the presence of suitably spaced hydrophobic residues, sequence specificities have also been associated with specific oligomeric states. RhXXhE is one such sequence motif, associated with parallel trimers, found in coronins and other proteins. Coronin, present in all eukaryotes, is an actin-associated protein involved in regulating actin turnover. Most eukaryotic coronins possess the RhXXhE trimerization motif. However, a unique feature of parasitic kinetoplastid coronin is that the positions of R and E are swapped within their coiled coil domain, but were still expected to form trimers. To understand the role of swapped motif in oligomeric specificity, we determined the X-ray crystal structure of Leishmania donovani coronin coiled coil domain (LdCoroCC) at 2.2Å, which surprisingly, reveals an anti-parallel tetramer assembly. Small angle X-ray scattering studies and chemical crosslinking confirm the tetramer in solution and is consistent with the oligomerization observed in the full length protein. Structural analyses reveal that LdCoroCC possesses an inherent asymmetry, in that one of the helices of the bundle is axially shifted with respect to the other three. The analysis also identifies steric reasons that cause this asymmetry. The bundle adapts an extended a-d-e core packing, the e residue being polar (with an exception) which results in a thermostable bundle with polar and apolar interfaces, unlike the existing a-d-e core antiparallel homotetramers with apolar core. Functional implications of the anti-parallel association in kinetoplastids are discussed. PMID:26940672

  11. Evidence from Raman Spectroscopy of a Putative Link Between Inherent Bone Matrix Chemistry and Degenerative Joint Disease

    PubMed Central

    Kerns, Jemma G; Gikas, Panagiotis D; Buckley, Kevin; Shepperd, Adam; Birch, Helen L; McCarthy, Ian; Miles, Jonathan; Briggs, Timothy W R; Keen, Richard; Parker, Anthony W; Matousek, Pavel; Goodship, Allen E

    2014-01-01

    Objective Osteoarthritis (OA) is a common debilitating disease that results in degeneration of cartilage and bone in the synovial joints. Subtle changes in the molecular structure of the subchondral bone matrix occur and may be associated with cartilage changes. The aim of this study was to explore whether the abnormal molecular changes observed in the matrix of OA subchondral bone can be identified with Raman spectroscopy. Methods Tibial plateaus from patients undergoing total knee replacement for OA (n = 10) were compared with healthy joints from patients undergoing leg amputation (n = 5; sex- and laterality-matched) and with non-OA cadaveric knee specimens (n = 5; age-matched). The samples were analyzed with Raman spectroscopy, peripheral quantitative computed tomography, and chemical analysis to compare changes in defined load-bearing sites in both the medial and lateral compartments. Results OA subchondral bone matrix changes were detected by Raman spectroscopy. Within each cohort, there was no spectral difference in bone matrix chemistry between the medial and lateral compartments, whereas a significant spectral difference (P < 0.001) was observed between the non-OA and OA specimens. Type I collagen chain ratios were normal in the non-OA specimens but were significantly elevated in the OA specimens. Conclusion In comparing the results of Raman spectroscopy with those obtained by other standard techniques, these findings show, for the first time, that subchondral bone changes, or inherent differences, exist in both the medial and lateral (beneath intact cartilage) compartments of OA knees. The development of Raman spectroscopy as a screening tool, based on molecular-specific modifications in bone, would facilitate the identification of clinical disease, including early molecular changes. PMID:24470432

  12. Influence of uncertainty inherent to heavy metal build-up and wash-off on stormwater quality.

    PubMed

    Wijesiri, Buddhi; Egodawatta, Prasanna; McGree, James; Goonetilleke, Ashantha

    2016-03-15

    Uncertainty inherent to heavy metal build-up and wash-off stems from process variability. This results in inaccurate interpretation of stormwater quality model predictions. The research study has characterised the variability in heavy metal build-up and wash-off processes based on the temporal variations in particle-bound heavy metals commonly found on urban roads. The study outcomes found that the distribution of Al, Cr, Mn, Fe, Ni, Cu, Zn, Cd and Pb were consistent over particle size fractions <150 μm and >150 μm, with most metals concentrated in the particle size fraction <150 μm. When build-up and wash-off are considered as independent processes, the temporal variations in these processes in relation to the heavy metals load are consistent with variations in the particulate load. However, the temporal variations in the load in build-up and wash-off of heavy metals and particulates are not consistent for consecutive build-up and wash-off events that occur on a continuous timeline. These inconsistencies are attributed to interactions between heavy metals and particulates <150 μm and >150 μm, which are influenced by particle characteristics such as organic matter content. The behavioural variability of particles determines the variations in the heavy metals load entrained in stormwater runoff. Accordingly, the variability in build-up and wash-off of particle-bound pollutants needs to be characterised in the description of pollutant attachment to particulates in stormwater quality modelling. This will ensure the accounting of process uncertainty, and thereby enhancing the interpretation of the outcomes derived from modelling studies. PMID:26803262

  13. Quaternary geomorphology and modern coastal development in response to an inherent geologic framework: An example from Charleston, South Carolina

    USGS Publications Warehouse

    Harris, M.S.; Gayes, P.T.; Kindinger, J.L.; Flocks, J.G.; Krantz, D.E.; Donovan, P.

    2005-01-01

    Coastal landscapes evolve over wide-ranging spatial and temporal scales in response to physical and biological pro-cesses that interact with a wide range of variables. To develop better predictive models for these dynamic areas, we must understand the influence of these variables on coastal morphologies and ultimately how they influence coastal processes. This study defines the influence of geologic framework variability on a classic mixed-energy coastline, and establishes four categorical scales of spatial and temporal influence on the coastal system. The near-surface, geologic framework was delineated using high-resolution seismic profiles, shallow vibracores, detailed geomorphic maps, historical shorelines, aerial photographs, and existing studies, and compared to the long- and short-term development of two coastal compartments near Charleston, South Carolina. Although it is clear that the imprint of a mixed-energy tidal and wave signal (basin-scale) dictates formation of drumstick barriers and that immediate responses to wave climate are dramatic, island size, position, and longer-term dynamics are influenced by a series of inherent, complex near-surface stratigraphic geometries. Major near-surface Tertiary geometries influence inlet placement and drainage development (island-scale) through multiple interglacial cycles and overall channel morphology (local-scale). During the modern marine transgression, the halo of ebb-tidal deltas greatly influence inlet region dynamics, while truncated beach ridges and exposed, differentially erodable Cenozoic deposits in the active system influence historical shoreline dynamics and active shoreface morphologies (blockscale). This study concludes that the mixed-energy imprint of wave and tide theories dominates general coastal morphology, but that underlying stratigraphic influences on the coast provide site-specific, long-standing imprints on coastal evolution.

  14. Effects of local field and inherent strain in reflectance anisotropy spectra of AIIIBV semiconductors with naturally oxidized surfaces

    NASA Astrophysics Data System (ADS)

    Berkovits, V. L.; Kosobukin, V. A.; Gordeeva, A. B.

    2015-12-01

    Reflectance anisotropy (RA) spectra of naturally oxidized (001) surfaces of GaAs and InAs crystals are measured for photon energies from 1.5 up to 5.5 eV. The differential high-accuracy RA spectra reveal features substantially different from those caused by either a reconstruction of clean surface or a built-in near-surface electric field. Models of atomic structure with anisotropic transition layers of excess arsenic atoms specific for GaAs(001)/oxide and InAs(001)/oxide interfaces are proposed. In conformity with these models, a general theory of reflectance anisotropy is developed for semiconductor/oxide interfaces within the Green's function technique. The theory takes into account the combined effect of local field due to interface dipoles and of intrinsic near-surface strain of the crystal. Measured RA spectra are analyzed in the model of valence-bond dipoles occupying a rectangular lattice in a multilayer medium. Comparing the measured and calculated spectra, we conclude that RA spectra of oxidized GaAs(001) and InAs(001) surfaces are simultaneously influenced by interface and near-surface anisotropies. The former is responsible for the broad-band spectral features which are associated with polarizability of the valence bonds attached to As atoms at the crystal/oxide interface. The near-surface anisotropy is due to inherent uniaxial straining the near-surface region of crystal. The effect of strain on RA spectra is experimentally and theoretically substantiated for GaAs crystal wafers undergone a uniaxial applied stress. Basically, this work results in the following. It establishes the physical nature of different levels of RA spectra observed in a majority of papers, but never analyzed. It demonstrates how the studied features of RA spectra could be applied for optical characterization of strained interfaces and atomic layers.

  15. Inherent point defects at the thermal higher-Miller index (211)Si/SiO{sub 2} interface

    SciTech Connect

    Iacovo, S.; Stesmans, A.

    2014-12-29

    Electron spin resonance (ESR) studies were carried out on the higher-Miller index (211)Si/SiO{sub 2} interface thermally grown in the temperature range T{sub ox} = 400–1066 °C to assess interface quality in terms of inherently incorporated point defects. This reveals the presence predominantly of two species of a P{sub b}-type interface defect (interfacial Si dangling bond), which, based on pertinent ESR parameters, is typified as P{sub b0}{sup (211)} variant, close to the P{sub b0} center observed in standard (100)Si/SiO{sub 2}—known as utmost detrimental interface trap. T{sub ox} ≳ 750 °C is required to minimize the P{sub b0}{sup (211)} defect density (∼4.2 × 10{sup 12 }cm{sup −2}; optimized interface). The data clearly reflect the non-elemental nature of the (211)Si face as an average of (100) and (111) surfaces. It is found that in oxidizing (211)Si at T{sub ox} ≳ 750 °C, the optimum Si/SiO{sub 2} interface quality is retained for the two constituent low-index (100) and (111) faces separately, indicating firm anticipating power for higher-index Si/SiO{sub 2} interfaces in general. It implies that, as a whole, the quality of a thermal higher-index Si/SiO{sub 2} interface can never surmount that of the low-index (100)Si/SiO{sub 2} structure.

  16. NASA Safety Manual. Volume 3: System Safety

    NASA Technical Reports Server (NTRS)

    1970-01-01

    This Volume 3 of the NASA Safety Manual sets forth the basic elements and techniques for managing a system safety program and the technical methods recommended for use in developing a risk evaluation program that is oriented to the identification of hazards in aerospace hardware systems and the development of residual risk management information for the program manager that is based on the hazards identified. The methods and techniques described in this volume are in consonance with the requirements set forth in NHB 1700.1 (VI), Chapter 3. This volume and future volumes of the NASA Safety Manual shall not be rewritten, reprinted, or reproduced in any manner. Installation implementing procedures, if necessary, shall be inserted as page supplements in accordance with the provisions of Appendix A. No portion of this volume or future volumes of the NASA Safety Manual shall be invoked in contracts.

  17. Safety Tips: Safety Is No Laughing Matter.

    ERIC Educational Resources Information Center

    Hill, Patricia S.; Greco, Thomas G.

    1995-01-01

    Presents the script of a skit designed to engage beginning students in a contest to identify and list the most safety violations they observe during the skit. Includes a list of 37 safe laboratory practices. (MKR)

  18. Are subsurface safety valves needed in deepwater?

    SciTech Connect

    Verret, A.; Hey, C.

    1995-11-01

    The object of this study was to evaluate SCSSV reliability and identify a preferred configuration for subsea completions in deepwater. A system design consisting of subsea, conventional, dual-bore tree, cluster wells was selected for evaluation. The study examined inherent risks associated with six tubing retrievable SCSSV configurations. Risks were evaluated for personnel and environmental safety, and operational and financial impact of: No SCSSV; Single SCSSV; Dual operating system single SCSSV; Tandem hot/hot (both valves active) SCSSVs without lockout features; Tandem hot/hot SCSSVs with lockout features; Tandem hot/cold (one valve active, the other dormant in open position) SCSSVs with lockout features. A ``fault tree`` identifying events that could lead to deleterious incidents was used to evaluate risks. Costs and consequences associated with potential events were determined using existing industry data, and resulting calculated risks were evaluated. Recommendations were developed and compared to current regulations, and potential regulatory conflicts were identified.

  19. NASA Software Safety Standard

    NASA Technical Reports Server (NTRS)

    Rosenberg, Linda

    1997-01-01

    If software is a critical element in a safety critical system, it is imperative to implement a systematic approach to software safety as an integral part of the overall system safety programs. The NASA-STD-8719.13A, "NASA Software Safety Standard", describes the activities necessary to ensure that safety is designed into software that is acquired or developed by NASA, and that safety is maintained throughout the software life cycle. A PDF version, is available on the WWW from Lewis. A Guidebook that will assist in the implementation of the requirements in the Safety Standard is under development at the Lewis Research Center (LeRC). After completion, it will also be available on the WWW from Lewis.

  20. Highway Safety Program Manual: Volume 14: Pedestrian Safety.

    ERIC Educational Resources Information Center

    National Highway Traffic Safety Administration (DOT), Washington, DC.

    Volume 14 of the 19-volume Highway Safety Program Manual (which provides guidance to State and local governments on preferred highway safety practices) concentrates on pedestrian safety. The purpose and objectives of a pedestrian safety program are outlined. Federal authority in the area of pedestrian safety and policies regarding a safety program…