Failure Diagnosis and Prognosis of Rolling - Element Bearings using Artificial Neural Networks: A Critical Overview

NASA Astrophysics Data System (ADS)

Rao, B. K. N.; Srinivasa Pai, P.; Nagabhushana, T. N.

2012-05-01

Rolling - Element Bearings are extensively used in almost all global industries. Any critical failures in these vitally important components would not only affect the overall systems performance but also its reliability, safety, availability and cost-effectiveness. Proactive strategies do exist to minimise impending failures in real time and at a minimum cost. Continuous innovative developments are taking place in the field of Artificial Neural Networks (ANNs) technology. Significant research and development are taking place in many universities, private and public organizations and a wealth of published literature is available highlighting the potential benefits of employing ANNs in intelligently monitoring, diagnosing, prognosing and managing rolling-element bearing failures. This paper attempts to critically review the recent trends in this topical area of interest.

Sustained Satellite Missions for Climate Data Records

NASA Technical Reports Server (NTRS)

Halpern, David

2012-01-01

Satellite CDRs possess the accuracy, longevity, and stability for sustained moni toring of critical variables to enhance understanding of the global integrated Earth system and predict future conditions. center dot Satellite CDRs are a critical element of a global climate observing system. center dot Satellite CDRs are a difficult challenge and require high - level managerial commitment, extensive intellectual capital, and adequate funding.

An autonomous structural health monitoring system for Waiau interchange.

DOT National Transportation Integrated Search

2013-03-01

Bridge infrastructure is a critical element of the transportation system which makes maintaining its safety and : performance vital to a healthy society. However, the civil infrastructure systems in the United States are decaying : at an accelerated ...

Atmospheric Research at BNL

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

Peter Daum

2008-10-06

Brookhaven researcher Peter Daum discusses an international field experiment designed to make observations of critical components of the climate system of the southeastern Pacific. Because elements of this system are poorly understood and poorly represent

Atmospheric Research at BNL

ScienceCinema

Peter Daum

2017-12-09

Brookhaven researcher Peter Daum discusses an international field experiment designed to make observations of critical components of the climate system of the southeastern Pacific. Because elements of this system are poorly understood and poorly represent

Moving Smart in Rhode Island

DOT National Transportation Integrated Search

2004-06-01

Real-time transportation system information is a critical element in the development of Intelligent Transportation Systems (ITS). The Rhode Island Department of Transportation (RIDOT) is in the process of developing a fully integrated intelligent tra...

Applying analysis tools in planning for operations

DOT National Transportation Integrated Search

2009-09-01

More and more, transportation system operators are seeing the benefits of strengthening links between planning and operations. A critical element in improving transportation decision-making and the effectiveness of transportation systems related to o...

Estimating optical imaging system performance for space applications

NASA Technical Reports Server (NTRS)

Sinclair, K. F.

1972-01-01

The critical system elements of an optical imaging system are identified and a method for an initial assessment of system performance is presented. A generalized imaging system is defined. A system analysis is considered, followed by a component analysis. An example of the method is given using a film imaging system.

Unobtainium? Critical Elements for New Energy Technologies

NASA Astrophysics Data System (ADS)

Jaffe, Robert

2011-03-01

I will report on a recently completed study jointly sponsored by the APS Panel on Public Affairs (POPA) and the Material Research Society (MRS). The twin pressures of increasing demand for energy and increasing concern about anthropogenic climate change have stimulated research into new sources of energy and novel ways to harvest, transmit, store, transform or conserve it. At the same time, advances in physics, chemistry, and material science have enabled researchers to identify chemical elements with properties that can be finely tuned to their specific needs and to employ them in new energy-related technologies. Elements like dysprosium, gallium, germanium, indium, lanthanum, neodymium, rhenium, or tellurium, which were once laboratory curiosities, now figure centrally when novel energy systems are discussed. Many of these elements are not at present mined, refined, or traded in large quantities. However new technologies can only impact our energy needs if they can be scaled from laboratory, to demonstration, to massive implementation. As a result, some previously unfamiliar elements will be needed in great quantities. We refer to these elements as energy-critical elements (ECEs). Although the technologies in which they are employed and their abundance in the Earth's crust vary greatly, ECEs have many features in common. The purpose of the POPA/MRS study was to evaluate constraints on availability of energy-critical elements and to make recommendations that can help avoid these obstructions.

Human Agency in Disaster Planning: A Systems Approach.

PubMed

Powell, John Hamer; Hammond, Michael; Chen, Albert; Mustafee, Navonil

2018-01-16

Current approaches to risk management place insufficient emphasis on the system knowledge available to the assessor, particularly in respect of the dynamic behavior of the system under threat, the role of human agents (HAs), and the knowledge available to those agents. In this article, we address the second of these issues. We are concerned with a class of systems containing HAs playing a variety of roles as significant system elements-as decisionmakers, cognitive agents, or implementers-that is, human activity systems. Within this family of HAS, we focus on safety and mission-critical systems, referring to this subclass as critical human activity systems (CHASs). Identification of the role and contribution of these human elements to a system is a nontrivial problem whether in an engineering context, or, as is the case here, in a wider social and public context. Frequently, they are treated as standing apart from the system in design or policy terms. Regardless of the process of policy definition followed, analysis of the risk and threats to such a CHAS requires a holistic approach, since the effect of undesirable, uninformed, or erroneous actions on the part of the human elements is both potentially significant to the system output and inextricably bound together with the nonhuman elements of the system. We present a procedure for identifying the potential threats and risks emerging from the roles and activity of those HAs, using the 2014 flooding in southwestern England and the Thames Valley as a contemporary example. © 2018 The Authors Risk Analysis published by Wiley Periodicals, Inc. on behalf of Society for Risk Analysis.

Satellite Power Systems (SPS) concept definition study exhibit C. Volume 3: Experimental verification definition

NASA Technical Reports Server (NTRS)

1979-01-01

An environmentally oriented microwave technology exploratory research program aimed at reducing the uncertainty associated with microwave power system critical technical issues is described. Topics discussed include: (1) Solar Power Satellite System (SPS) development plan elements; (2) critical technology issues related to the SPS preliminary reference configuration; (3) pilot plant to demonstrate commercial viability of the SPS system; and (4) research areas required to demonstrate feasibility of the SPS system. Progress in the development of advanced GaAs solar cells is reported along with a power distribution subsystem.

Finite Macro-Element Mesh Deformation in a Structured Multi-Block Navier-Stokes Code

NASA Technical Reports Server (NTRS)

Bartels, Robert E.

2005-01-01

A mesh deformation scheme is developed for a structured multi-block Navier-Stokes code consisting of two steps. The first step is a finite element solution of either user defined or automatically generated macro-elements. Macro-elements are hexagonal finite elements created from a subset of points from the full mesh. When assembled, the finite element system spans the complete flow domain. Macro-element moduli vary according to the distance to the nearest surface, resulting in extremely stiff elements near a moving surface and very pliable elements away from boundaries. Solution of the finite element system for the imposed boundary deflections generally produces smoothly varying nodal deflections. The manner in which distance to the nearest surface has been found to critically influence the quality of the element deformation. The second step is a transfinite interpolation which distributes the macro-element nodal deflections to the remaining fluid mesh points. The scheme is demonstrated for several two-dimensional applications.

Reference Avionics Architecture for Lunar Surface Systems

NASA Technical Reports Server (NTRS)

Somervill, Kevin M.; Lapin, Jonathan C.; Schmidt, Oron L.

2010-01-01

Developing and delivering infrastructure capable of supporting long-term manned operations to the lunar surface has been a primary objective of the Constellation Program in the Exploration Systems Mission Directorate. Several concepts have been developed related to development and deployment lunar exploration vehicles and assets that provide critical functionality such as transportation, habitation, and communication, to name a few. Together, these systems perform complex safety-critical functions, largely dependent on avionics for control and behavior of system functions. These functions are implemented using interchangeable, modular avionics designed for lunar transit and lunar surface deployment. Systems are optimized towards reuse and commonality of form and interface and can be configured via software or component integration for special purpose applications. There are two core concepts in the reference avionics architecture described in this report. The first concept uses distributed, smart systems to manage complexity, simplify integration, and facilitate commonality. The second core concept is to employ extensive commonality between elements and subsystems. These two concepts are used in the context of developing reference designs for many lunar surface exploration vehicles and elements. These concepts are repeated constantly as architectural patterns in a conceptual architectural framework. This report describes the use of these architectural patterns in a reference avionics architecture for Lunar surface systems elements.

Effect of Bending Stiffness of the Electroactive Polymer Element on the Performance of a Hybrid Actuator System (HYBAS)

NASA Technical Reports Server (NTRS)

Xu, Tian-Bing; Su, Ji; Jiang, Xiaoning; Rehrig, Paul W.; Zhang, Shujun; Shrout, Thomas R.; Zhang, Qiming

2006-01-01

An electroactive polymer (EAP)-ceramic hybrid actuation system (HYBAS) was developed recently at NASA Langley Research Center. This paper focuses on the effect of the bending stiffness of the EAP component on the performance of a HYBAS, in which the actuation of the EAP element can match the theoretical prediction at various length/thickness ratios for a constant elastic modulus of the EAP component. The effects on the bending stiffness of the elastic modulus and length/thickness ratio of the EAP component were studied. A critical bending stiffness to keep the actuation of the EAP element suitable for a rigid beam theory-based modeling was found for electron irradiated P(VDF-TrFE) copolymer. For example, the agreement of experimental data and theoretical modeling for a HYBAS with the length/thickness ratio of EAP element at 375 times is demonstrated. However, the beam based theoretical modeling becomes invalid (i.e., the profile of the HYBAS movement does not follow the prediction of theoretical modeling) when the bending stiffness is lower than a critical value.

Technology for the Future: In-Space Technology Experiments Program, part 2

NASA Technical Reports Server (NTRS)

Breckenridge, Roger A. (Compiler); Clark, Lenwood G. (Compiler); Willshire, Kelli F. (Compiler); Beck, Sherwin M. (Compiler); Collier, Lisa D. (Compiler)

1991-01-01

The purpose of the Office of Aeronautics and Space Technology (OAST) In-Space Technology Experiments Program In-STEP 1988 Workshop was to identify and prioritize technologies that are critical for future national space programs and require validation in the space environment, and review current NASA (In-Reach) and industry/ university (Out-Reach) experiments. A prioritized list of the critical technology needs was developed for the following eight disciplines: structures; environmental effects; power systems and thermal management; fluid management and propulsion systems; automation and robotics; sensors and information systems; in-space systems; and humans in space. This is part two of two parts and contains the critical technology presentations for the eight theme elements and a summary listing of critical space technology needs for each theme.

49 CFR 236.1041 - Training and qualification program, general.

Code of Federal Regulations, 2010 CFR

2010-10-01

... INSTALLATION, INSPECTION, MAINTENANCE, AND REPAIR OF SIGNAL AND TRAIN CONTROL SYSTEMS, DEVICES, AND APPLIANCES Positive Train Control Systems § 236.1041 Training and qualification program, general. (a) Training program...-critical elements of the railroad's PTC systems, including central office, wayside, or onboard subsystems...

Exploration Life Support Critical Questions for Future Human Space Missions

NASA Technical Reports Server (NTRS)

Kwert, Michael K.; Barta, Daniel J.; McQuillan, Jeff

2010-01-01

Exploration Life Support (ELS) is a current project under NASA's Exploration Systems Mission Directorate. The ELS Project plans, coordinates and implements the development of advanced life support technologies for human exploration missions in space. Recent work has focused on closed loop atmosphere and water systems for long duration missions, including habitats and pressurized rovers. But, what are the critical questions facing life support system developers for these and other future human missions? This paper explores those questions and how progress in the development of ELS technologies can help answer them. The ELS Project includes the following Elements: Atmosphere Revitalization Systems, Water Recovery Systems, Waste Management Systems, Habitation Engineering, Systems Integration, Modeling and Analysis, and Validation and Testing, which includes the Sub-Elements Flight Experiments and Integrated Testing. Systems engineering analysis by ELS seeks to optimize overall mission architectures by considering all the internal and external interfaces of the life support system and the potential for reduction or reuse of commodities. In particular, various sources and sinks of water and oxygen are considered along with the implications on loop closure and the resulting launch mass requirements. Systems analysis will be validated through the data gathered from integrated testing, which will demonstrate the interfaces of a closed loop life support system. By applying a systematic process for defining, sorting and answering critical life support questions, the ELS project is preparing for a variety of future human space missions

Critical Leadership and Music Educational Practice

ERIC Educational Resources Information Center

Schmidt, Patrick K.

2012-01-01

The difference between systemic change and the micro level engagements or modest kinds of successes that teachers hope for is a largely unaddressed issue in music education policy and leadership. This article outlines a few propositions that place the notion of critical leadership as a central element in music and education focusing on the notion…

PROTECTING THE NATION'S CRITICAL INFRASTRUCTURE: THE VULNERABILITY OF U.S. WATER SUPPLY SYSTEMS

EPA Science Inventory

Terrorism in the United States was not considered a serious threat until the second half of the 1990s. However, recent attacks both at home and abroad have forced government planners to consider the possibility that critical elements of the U.S. infrastructure might in fact be vu...

Solar electric propulsion thrust subsystem development

NASA Technical Reports Server (NTRS)

Masek, T. D.

1973-01-01

The Solar Electric Propulsion System developed under this program was designed to demonstrate all the thrust subsystem functions needed on an unmanned planetary vehicle. The demonstration included operation of the basic elements, power matching input and output voltage regulation, three-axis thrust vector control, subsystem automatic control including failure detection and correction capability (using a PDP-11 computer), operation of critical elements in thermal-vacuum-, zero-gravity-type propellant storage, and data outputs from all subsystem elements. The subsystem elements, functions, unique features, and test setup are described. General features and capabilities of the test-support data system are also presented. The test program culminated in a 1500-h computer-controlled, system-functional demonstration. This included simultaneous operation of two thruster/power conditioner sets. The results of this testing phase satisfied all the program goals.

Leaching behavior of rare earth elements in Fort Union lignite coals of North America

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

Laudal, Daniel A.; Benson, Steven A.; Addleman, Raymond Shane

Rare earth elements are crucial materials in an incredible array of consumer goods, energy system components and military defense applications. However, the global production and entire value chain for rare earth elements is dominated by China, with the U.S. currently 100% import reliant for these critical materials. Traditional mineral ores including those previously mined in the U.S., however, have several challenges. Chief among these is that the content of the most critical and valuable of the rare earths are deficient, making mining uneconomical. Further, the supply of these most critical rare earths is nearly 100% produced in China from amore » single resource that is only projected to last another 10 to 20 years. The U.S. currently considers the rare earths market an issue of national security. It is imperative that alternative domestic sources of rare earths be identified and methods developed to produce them. Recently, coal and coal byproducts have been identified as one of these promising alternative resources. This paper details the results of a study on characterization of North Dakota lignite and lignite-related feedstocks as an assessment of their feasibility for rare earth element recovery. The abundance, distribution and modes of occurrence of the rare earth elements in the samples collected were determined in this initial study to inform the selection of appropriate extraction and concentration methods to recover the rare earth elements. Materials investigated include the lignite coals, clay-rich sediments associated with the coal seams, and materials associated with a lignite beneficiation system and power plant. The results show that high rare earth element levels exist both in lignite coals and associated sediments. The form of the rare earth elements in the clay materials is primarily as ultra-fine mineral grains. In the lignite coals, approximately 80-95% of the rare earths content is organically associated, primarily as coordination complexes.« less

Dynamic analysis and vibration testing of CFRP drive-line system used in heavy-duty machine tool

NASA Astrophysics Data System (ADS)

Yang, Mo; Gui, Lin; Hu, Yefa; Ding, Guoping; Song, Chunsheng

2018-03-01

Low critical rotary speed and large vibration in the metal drive-line system of heavy-duty machine tool affect the machining precision seriously. Replacing metal drive-line with the CFRP drive-line can effectively solve this problem. Based on the composite laminated theory and the transfer matrix method (TMM), this paper puts forward a modified TMM to analyze dynamic characteristics of CFRP drive-line system. With this modified TMM, the CFRP drive-line of a heavy vertical miller is analyzed. And the finite element modal analysis model of the shafting is established. The results of the modified TMM and finite element analysis (FEA) show that the modified TMM can effectively predict the critical rotary speed of CFRP drive-line. And the critical rotary speed of CFRP drive-line is 20% higher than that of the original metal drive-line. Then, the vibration of the CFRP and the metal drive-line were tested. The test results show that application of the CFRP drive shaft in the drive-line can effectively reduce the vibration of the heavy-duty machine tool.

Visual Links in the World-Wide Web: The Uses and Limitations of Image Maps.

ERIC Educational Resources Information Center

Cochenour, John J.; And Others

As information delivery systems on the Internet increasingly evolve into World Wide Web browsers, understanding key graphical elements of the browser interface is critical to the design of effective information display and access tools. Image maps are one such element, and this document describes a pilot study that collected, reviewed, and…

Power system characteristics for more electric aircraft

NASA Technical Reports Server (NTRS)

Hansen, Irving G.

1993-01-01

It should not be suprising that more electric aircraft must meet significantly more difficult electrical power system requirements than were considereed when today's power distribution systems were being developed. Electric power, no longer a secondary system, will become a critical element of the primary control system. Functional reliability requiirements will be extremely stringent and can only be met by controlling element redundancy within a distributed power system. Existing electrical systems were not developed to have both the power system and the control/sensing elements distributed and yet meet the requirements of lighting tolerance and high intensity radio frequency (HIRF). In addition, the operation of electric actuators involves high transient loading and reverse energy flows. Such phenomena were also not anticipated when power quality was specified for either 270 vdc or 400 Hertz ac power systems. This paper will expand upon the issues and discuss some of the technologies involved in their resolution.

Elements for harnessing participatory action research to strengthen health managers' capacity: a critical interpretative synthesis.

PubMed

Tetui, Moses; Zulu, Joseph Mumba; Hurtig, Anna-Karin; Ekirapa-Kiracho, Elizabeth; Kiwanuka, Suzanne N; Coe, Anna-Britt

2018-04-19

Health managers play a key role in ensuring that health services are responsive to the needs of the population. Participatory action research (PAR) is one of the approaches that have been used to strengthen managers' capacity. However, collated knowledge on elements for harnessing PAR to strengthen managers' capacity is missing. This paper bridges this gap by reviewing existing literature on the subject matter. A critical interpretive synthesis method was used to interrogate eight selected articles. These articles reported the use of PAR to strengthen health managers' capacity. The critical interpretive synthesis method's approach to analysis guided the synthesis. Here, the authors interpretively made connections and linkages between different elements identified in the literature. Finally, the Atun et al. (Heal Pol Plann, 25:104-111, 2010) framework on integration was used to model the elements synthesised in the literature into five main domains. Five elements with intricate bi-directional interactions were identified in the literature reviewed. These included a shared purpose, skilled facilitation and psychological safety, activity integration into organisational procedures, organisational support, and external supportive monitoring. A shared purpose of the managers' capacity strengthening initiative created commitment and motivation to learn. This purpose was built upon a set of facilitation skills that included promoting participation, self-efficacy and reflection, thereby creating a safe psychological space within which the managers interacted and learnt from each other and their actions. Additionally, an integrated intervention strengthened local capacity and harnessed organisational support for learning. Finally, supportive monitoring from external partners, such as researchers, ensured quality, building of local capacity and professional safety networks essential for continued learning. The five elements identified in this synthesis provide a basis upon which the use of PAR can be harnessed, not only to strengthen health managers' capacity, but also to foster other health systems strengthening initiatives involving implementation research. In addition, the findings demonstrated the intricate and complex relations between the elements, which further affirms the need for a systems thinking approach to tackling health systems challenges.

Using Mobile Devices to Enhance the Interactive Learning for Spatial Geometry

ERIC Educational Resources Information Center

Chang, Kuo-En; Wu, Lin-Jung; Lai, Shing-Chuang; Sung, Yao-Ting

2016-01-01

The purpose of this research is to develop a hands-on spatial geometry learning system to facilitate the learning of geometry. The development of this system was based on Duval's four critical elements of geometric learning: perceptual apprehension, sequential apprehension, operative apprehension, and discursive apprehension. The system offers…

World Materials Summit (3rd). Held in Washington, DC on 9-12 October, 2011

DTIC Science & Technology

2012-05-23

It focused on the critical links among materials research, energy, and sustainable development on a global scale. Abundant clean energy supplies and...reliable energy storage systems are needed to address many critical societal issues in development and developed countries. On a broader scale, access...Houle of the Lawrence Berkeley National Laboratory spoke next about "Energy Critical Elements," focusing on the well-known shortage of rare earth (RE

PATHFINDER ATOMIC POWER PLANT TECHNICAL PROGRESS REPORT FOR JULY 1, 1959- SEPTEMBER 30, 1959

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

None

1960-10-31

ABS>Fuel Element Research and Development. Dynamic and static corrosion tests on 8001 Al were completed. Annealmmmg of 1100 cladding on 5083 and M400 cladding on X2219 were tested at 500 deg C, and investigation continued on producing X8101 Al alloy cladding in tube plates by extrusion. Boiler fuel element capsule irradiation tests and subassembly tests are described Heat transfer loop studies and fuel fabrication for the critical facility are reported. Boiler fuel element mechanical design and testing progress is desc ribed. and the superheater fuel element temperature evaluating routine is discussed. Low- enrichment superheater fuel element development included design studiesmore » and stainless steel powder and UO/sub 2/ powder fabrication studies Reactor Mechanical Studies. Research is reported on vessel and structure design, fabrication, and testing, recirculation system design, steam separator tests, and control rod studies. Nuclear Analysis. Reactor physics studies are reported on nuclear constants, baffle plate analysis, comparison of core representations, delayed neutron fraction. and shielding analysis of the reactor building. Reactor and system dynamics and critical experiments were also studied. Chemistry. Progress is reported on recombiner. radioactive gas removal and storage, ion exchanger and radiochemical processing. (For preceding period see ACNP-5915.) (T.R.H.)« less

Modeling of Plutonium Ionization Probabilities for Use in Nuclear Forensic Analysis by Resonance Ionization Mass Spectrometry

DTIC Science & Technology

2016-12-01

masses collide, they form a supercritical mass . Criticality refers to the neutron population within the system. A critical system is one that can...Spectrometry, no. 242, pp. 161–168, 2005. [9] S. Raeder, “Trace analysis of actinides in the environment by means of resonance ionization mass ...first ionization potential of actinide elements by resonance ionization mass spectrometry.” Spectrochimica Acta part B: Atomic Spectroscopy. vol. 52

Applying analysis tools in planning for operations : case study #1 -- operations strategy impact reference and deployment guidance

DOT National Transportation Integrated Search

2009-09-01

More and more, transportation system operators are seeing the benefits of strengthening links between planning and operations. A critical element in improving transportation decision-making and the effectiveness of transportation systems related to o...

Change management and clinical engagement: critical elements for a successful clinical information system implementation.

PubMed

Detwiller, Maureen; Petillion, Wendy

2014-06-01

Moving a large healthcare organization from an old, nonstandardized clinical information system to a new user-friendly, standards-based system was much more than an upgrade to technology. This project to standardize terminology, optimize key processes, and implement a new clinical information system was a large change initiative over 4 years that affected clinicians across the organization. Effective change management and engagement of clinical stakeholders were critical to the success of the initiative. The focus of this article was to outline the strategies and methodologies used and the lessons learned.

Applying analysis tools in planning for operations : case study #3 -- using archived data as a tool for operations planning

DOT National Transportation Integrated Search

2009-09-01

More and more, transportation system operators are seeing the benefits of strengthening links between planning and operations. A critical element in improving transportation decision-making and the effectiveness of transportation systems related to o...

Applying analysis tools in planning for operations : case study #4 -- application of microsimulation in combination with travel demand models

DOT National Transportation Integrated Search

2009-09-01

More and more, transportation system operators are seeing the benefits of strengthening links between planning and operations. A critical element in improving transportation decision-making and the effectiveness of transportation systems related to o...

News: Tripping over tipping points/elements

EPA Science Inventory

The term “tipping point” has been used to identify a critical threshold susceptible to a tiny perturbation that can qualitatively alter the state or development of a system. “Tipping element” has been introduced to describe large-scale components of the Earth system that may pass...

Applying analysis tools in planning for operations : case study #2 -- incorporating Highway Capacity Manual procedures into long-range transportation planning

DOT National Transportation Integrated Search

2009-09-01

More and more, transportation system operators are seeing the benefi ts of strengthening links between : planning and operations. A critical element in improving transportation decision-making and the effectiveness : of transportation systems related...

Early Detection of Regime Shifts in Complex Systems from Fisher Information

EPA Science Inventory

The central goal of sustainability is the maintenance of environmental conditions, which are favorable to human existence. A critically important element then is the resilience of the dynamic regime that one wishes to sustain. Resilient systems are able to withstand perturbations...

ROMPS critical design review data package

NASA Technical Reports Server (NTRS)

Dobbs, M. E.

1992-01-01

The design elements of the Robot-Operated Material Processing in Space (ROMPS) system are described in outline and graphical form. The following subsystems/topics are addressed: servo system, testbed and simulation results, System V Controller, robot module, furnace module, SCL experiment supervisor and script sample processing control, battery system, watchdog timers, mechanical/thermal considerations, and fault conditions and recovery.

Mario Bunge's Philosophy of Mathematics: An Appraisal

ERIC Educational Resources Information Center

Marquis, Jean-Pierre

2012-01-01

In this paper, I present and discuss critically the main elements of Mario Bunge's philosophy of mathematics. In particular, I explore how mathematical knowledge is accounted for in Bunge's systemic emergent materialism.

Fact Sheets about the Fourth Unregulated Contaminant Monitoring Rule (UCMR 4)

EPA Pesticide Factsheets

Fact Sheets explaining the program, contaminants for monitoring, water systems applicable, timeframe & monitoring frequency, monitoring locations, critical requirements, data elements and where to find additional information on monitoring data.

Accreditation of Continuing Education: The Critical Elements.

ERIC Educational Resources Information Center

DeSilets, Lynore D.

1998-01-01

Reviews the history of accreditation in nursing continuing education, describes the system and process, and identifies institutional characteristics needed before beginning the process. Uses the American Nurses Center Commission on Accreditation model. (Author/SK)

Effect of DGPS failures on dynamic positioning of mobile drilling units in the North Sea.

PubMed

Chen, Haibo; Moan, Torgeir; Verhoeven, Harry

2009-11-01

Basic features of differential global positioning system (DGPS), and its operational configuration on dynamically positioned (DP) mobile offshore drilling units in the North Sea are described. Generic failure modes of DGPS are discussed, and a critical DGPS failure which has the potential to cause drive-off for mobile drilling units is identified. It is the simultaneous erroneous position data from two DGPS's. Barrier method is used to analyze this critical DGPS failure. Barrier elements to prevent this failure are identified. Deficiencies of each barrier element are revealed based on the incidents and operational experiences in the North Sea. Recommendations to strengthen these barrier elements, i.e. to prevent erroneous position data from DGPS, are proposed. These recommendations contribute to the safety of DP operations of mobile offshore drilling units.

Regionalization in the SUS: implementation process, challenges and perspectives in the critical view of system managers.

PubMed

Carvalho, Andre Luis Bonifácio de; Jesus, Washington Luiz Abreu de; Senra, Isabel Maria Vilas Boas

2017-04-01

This article examines the regionalization process in the Brazilian Health System, identifying frameworks and challenges of this process from critical dialogue on the subject, contextualized by the experience of the management system and in the light of an established theoretical debate in the last decade. We used the thematic content analysis of legal and documentary surveys of the regionalization process in SUS, collated by elements of the historical and political context in the period. As evidence, it appears that the regionalization process has been incremental decentralization/deconcentration of management and health actions and services. There are important challenges, particularly in relation to ensuring access and system governance structure, which contributes to critical thinking and construction of new perspectives by those who lead their implementation.

CCA Test Objectives

NASA Technical Reports Server (NTRS)

2005-01-01

Three sources have been considered to provide information allowing the evaluation of the Collision Conflict Avoidance (CCA) functional requirements: existing data, simulation, and flight test. The existing data sources that have been evaluated have been found to be lacking in two areas: The actual data that was recorded and missing elements to the system architecture. Many previous tests addressing collision avoidance were conducted without a remote operator. As such, they are missing critical elements that are required to assess the CCA functional requirements. Tests such as ERAST were conducted with all of the UAS elements. However, ERAST tests were conducted as a demonstration and the data recorded was of end-to-end performance. Many contributing elements of the system were not individually recorded or were recorded at a data rate insufficient for the purposes of evaluating the CCA functional requirements.

Simulators for Mariner Training and Licensing: Guidelines for Deck Officer Training Systems.

DTIC Science & Technology

1982-12-01

Information regarding the three major elements of the training system - the simu- lator design , the training program structure, and the instructor...1.1.2 Empirical Research/ Experimentation Phase ........................................ 1 1.1.3 Major Product...3 3.2 Simulator Design (Critical Characteristics) ......................................... 13 3.2.1 Visual Scee

78 FR 21389 - Notice of Issuance of Final Determination Concerning Certain Ultrasound Systems

Federal Register 2010, 2011, 2012, 2013, 2014

2013-04-10

... ultrasound units, known as the S2000 and Antares ultrasound systems, engineered, designed, and subject to... healthcare professionals. One of the most critical elements required for the manufacture of a functional... use of licensing keys. Manufacturing Process Electronics Module Assembly: You state that the...

Cost Allocation Issues in Interlibrary Systems.

ERIC Educational Resources Information Center

Alexander, Ernest R.

1985-01-01

In comparing methods of allocating service transaction costs among member libraries of interlibrary systems, questions of how costs are to be estimated, and what cost elements are to be included are critical. Different approaches of estimation yield varying results. Actual distribution of units accounts for greatest variance in allocations. (CDD)

Information at the edge of chaos in fluid neural networks

NASA Astrophysics Data System (ADS)

Solé, Ricard V.; Miramontes, Octavio

1995-01-01

Fluid neural networks, defined as neural nets of mobile elements with random activation, are studied by means of several approaches. They are proposed as a theoretical framework for a wide class of systems as insect societies, collectives of robots or the immune system. The critical properties of this model are also analysed, showing the existence of a critical boundary in parameter space where maximum information transfer occurs. In this sense, this boundary is in fact an example of the “edge of chaos” in systems like those described in our approach. Recent experiments with ant colonies seem to confirm our result.

Monitoring Ecosystems and Biodiversity at a Continental Scale--A Proposal for South America

Treesearch

Xavier Silva

2006-01-01

A monitoring system plan is being developed in South America to assess critically endangered ecoregions. The system will be based on a previous ecosystem and biodiversity inventory developed through a large gap analysis program in five South American ecoregions. The monitoring system will include three main elements: (1) Landscape Ecology: vegetation cover,...

Modeling of composite hydrogen storage cylinders using finite element analysis

DOT National Transportation Integrated Search

2008-02-01

Pressurized hydrogen storage cylinders are critical components of hydrogen transportation systems. Composite cylinders have pressure/thermal relief devices that are activated in case of an emergency. The difficulty in accurately analyzing the behavio...

Smoke Detection: Critical Element of a University Residential Fire Safety Program.

ERIC Educational Resources Information Center

Robinson, Donald A.

1979-01-01

A program at the University of Massachusetts/Amherst to assess the fire protection needs of its residential system is described. The study culminated in a multiphase fire safety improvement plan. (JMF)

A Power Conversion Concept for the Jupiter Icy Moons Orbiter

NASA Technical Reports Server (NTRS)

Mason, Lee S.

2003-01-01

The Jupiter Icy Moons Orbiter (JIMO) is a bold new mission under development by the Office of Space Science at NASA Headquarters. ITMO is examining the potential of Nuclear Electric Propulsion (NEP) technology to efficiently deliver scientific payloads to three Jovian moons: Callisto, Ganymede, and Europa. A critical element of the NEP vehicle is the reactor power system, consisting of the nuclear reactor, power conversion, heat rejection, and power management and distribution (PMAD). The emphasis of this paper is on the non-nuclear elements of the reactor power system.

Three tenets for secure cyber-physical system design and assessment

NASA Astrophysics Data System (ADS)

Hughes, Jeff; Cybenko, George

2014-06-01

This paper presents a threat-driven quantitative mathematical framework for secure cyber-physical system design and assessment. Called The Three Tenets, this originally empirical approach has been used by the US Air Force Research Laboratory (AFRL) for secure system research and development. The Tenets were first documented in 2005 as a teachable methodology. The Tenets are motivated by a system threat model that itself consists of three elements which must exist for successful attacks to occur: - system susceptibility; - threat accessibility and; - threat capability. The Three Tenets arise naturally by countering each threat element individually. Specifically, the tenets are: Tenet 1: Focus on What's Critical - systems should include only essential functions (to reduce susceptibility); Tenet 2: Move Key Assets Out-of-Band - make mission essential elements and security controls difficult for attackers to reach logically and physically (to reduce accessibility); Tenet 3: Detect, React, Adapt - confound the attacker by implementing sensing system elements with dynamic response technologies (to counteract the attackers' capabilities). As a design methodology, the Tenets mitigate reverse engineering and subsequent attacks on complex systems. Quantified by a Bayesian analysis and further justified by analytic properties of attack graph models, the Tenets suggest concrete cyber security metrics for system assessment.

Mining Critical Metals and Elements from Seawater: Opportunities and Challenges.

PubMed

Diallo, Mamadou S; Kotte, Madhusudhana Rao; Cho, Manki

2015-08-18

The availability and sustainable supply of technology metals and valuable elements is critical to the global economy. There is a growing realization that the development and deployment of the clean energy technologies and sustainable products and manufacturing industries of the 21st century will require large amounts of critical metals and valuable elements including rare-earth elements (REEs), platinum group metals (PGMs), lithium, copper, cobalt, silver, and gold. Advances in industrial ecology, water purification, and resource recovery have established that seawater is an important and largely untapped source of technology metals and valuable elements. This feature article discusses the opportunities and challenges of mining critical metals and elements from seawater. We highlight recent advances and provide an outlook of the future of metal mining and resource recovery from seawater.

Technology-Critical Elements: Economic and Policy Perspectives

NASA Astrophysics Data System (ADS)

Eggert, R. G.

2017-12-01

Critical elements are those that provide essential functionality to modern engineered materials, have few ready substitutes and are subject to supply-chain risks or concerns about long-run availability. This paper provides economic and public-policy perspectives on critical elements. It suggests: that which elements are critical is situational and changes over time; that we are not running out of mineral-derived raw materials in a geologic sense but rather, for some elements, face scarcities that are technological, environmental, political or economic in nature; and that public policy's most important role over the longer term is fostering scientific and technological innovation, especially early stage research, that has the potential to overcome these scarcities.

Service Modeling Language Applied to Critical Infrastructure

NASA Astrophysics Data System (ADS)

Baldini, Gianmarco; Fovino, Igor Nai

The modeling of dependencies in complex infrastructure systems is still a very difficult task. Many methodologies have been proposed, but a number of challenges still remain, including the definition of the right level of abstraction, the presence of different views on the same critical infrastructure and how to adequately represent the temporal evolution of systems. We propose a modeling methodology where dependencies are described in terms of the service offered by the critical infrastructure and its components. The model provides a clear separation between services and the underlying organizational and technical elements, which may change in time. The model uses the Service Modeling Language proposed by the W3 consortium for describing critical infrastructure in terms of interdependent services nodes including constraints, behavior, information flows, relations, rules and other features. Each service node is characterized by its technological, organizational and process components. The model is then applied to a real case of an ICT system for users authentication.

NEXT Single String Integration Test Results

NASA Technical Reports Server (NTRS)

Soulas, George C.; Patterson, Michael J.; Pinero, Luis; Herman, Daniel A.; Snyder, Steven John

2010-01-01

As a critical part of NASA's Evolutionary Xenon Thruster (NEXT) test validation process, a single string integration test was performed on the NEXT ion propulsion system. The objectives of this test were to verify that an integrated system of major NEXT ion propulsion system elements meets project requirements, to demonstrate that the integrated system is functional across the entire power processor and xenon propellant management system input ranges, and to demonstrate to potential users that the NEXT propulsion system is ready for transition to flight. Propulsion system elements included in this system integration test were an engineering model ion thruster, an engineering model propellant management system, an engineering model power processor unit, and a digital control interface unit simulator that acted as a test console. Project requirements that were verified during this system integration test included individual element requirements ; integrated system requirements, and fault handling. This paper will present the results of these tests, which include: integrated ion propulsion system demonstrations of performance, functionality and fault handling; a thruster re-performance acceptance test to establish baseline performance: a risk-reduction PMS-thruster integration test: and propellant management system calibration checks.

Implementing a Redesign Strategy: Lessons from Educational Change.

ERIC Educational Resources Information Center

Basom, Richard E., Jr.; Crandall, David P.

The effective implementation of school redesign, based on a social systems approach, is discussed in this paper. A basic assumption is that the interdependence of system elements has implications for a complex change process. Seven barriers to redesign and five critical issues for successful redesign strategy are presented. Seven linear steps for…

Guest Commentary: Global Environmental Education: A Complex Web of Reactions and Repercussions.

ERIC Educational Resources Information Center

Stapp, William B.; Mann, Lori

1985-01-01

Argues that interdependence among all living systems on earth is a necessary element in solving environmental problems, stressing similarities among international political systems and cultures. The ultimate challenge of environmental education is to bring individuals of all ages to critical understanding of the oneness of the earth. (DH)

Systemic Success in Physical Education: The East Valley Phenomenon

ERIC Educational Resources Information Center

Prusak, Keven A.; Pennington, Todd; Graser, Susan Vincent; Beighle, Aaron; Morgan, Charles F.

2010-01-01

Siedentop and Locke (1997) proposed three critical elements that must exist in our profession to make a difference and achieve systemic success in physical education (SSPE): (a) quality PE in the schools, (b) effective physical education teacher education (PETE)programs, and (c) a working relationship between the two. Using Cuban's (1992)…

5 CFR 430.207 - Monitoring performance.

Code of Federal Regulations, 2013 CFR

2013-01-01

... appraisal program shall include methods for appraising each critical and non-critical element during the appraisal period. Performance on each critical and non-critical element shall be appraised against its... provide assistance whenever performance is determined to be below “Fully Successful” or equivalent but...

5 CFR 430.207 - Monitoring performance.

Code of Federal Regulations, 2011 CFR

2011-01-01

... appraisal program shall include methods for appraising each critical and non-critical element during the appraisal period. Performance on each critical and non-critical element shall be appraised against its... provide assistance whenever performance is determined to be below “Fully Successful” or equivalent but...

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

Makarov, Pavel V., E-mail: pvm@ispms.tsc.ru

An evolutionary approach to earthquake development is proposed. A medium under loading is treated as a multiscale nonlinear dynamic system. Its failure involves a number of stages typical of any dynamic system: dynamic chaos, self-organized criticality, and global stability loss in the final stage of its evolution. In the latter stage, the system evolves in a blow-up mode accompanied by catastrophic superfast movements of the elements of this geomedium.

RF Spectrum Sensing Based on an Overdamped Nonlinear Oscillator Ring for Cognitive Radios.

PubMed

Tang, Zhi-Ling; Li, Si-Min; Yu, Li-Juan

2016-06-09

Existing spectrum-sensing techniques for cognitive radios require an analog-to-digital converter (ADC) to work at high dynamic range and a high sampling rate, resulting in high cost. Therefore, in this paper, a spectrum-sensing method based on a unidirectionally coupled, overdamped nonlinear oscillator ring is proposed. First, the numerical model of such a system is established based on the circuit of the nonlinear oscillator. Through numerical analysis of the model, the critical condition of the system's starting oscillation is determined, and the simulation results of the system's response to Gaussian white noise and periodic signal are presented. The results show that once the radio signal is input into the system, it starts oscillating when in the critical region, and the oscillating frequency of each element is fo/N, where fo is the frequency of the radio signal and N is the number of elements in the ring. The oscillation indicates that the spectrum resources at fo are occupied. At the same time, the sampling rate required for an ADC is reduced to the original value, 1/N. A prototypical circuit to verify the functionality of the system is designed, and the sensing bandwidth of the system is measured.

Desktop Systems for Manufacturing Carbon Nanotube Films by Chemical Vapor Deposition

DTIC Science & Technology

2007-06-01

existing low cost tube furnace designs limit the researcher’s ability to fully separate critical reaction parameters such as temperature and flow...Often heated using an external resistive heater coil, a typical configuration, shown in Figure 4, might place a tube made of a non- reactive ...researcher’s ability to fully separate critical parameters such as temperature and flow profiles. Additionally, the use of heating elements external to

Development of an integrated transuranic waste management system for a large research facility: NUCEF

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

Mineo, Hideaki; Matsumura, Tatsuro; Takeshita, Isao

1997-03-01

The Nuclear Fuel Cycle Safety Engineering Research Facility (NUCEF) is a large complex of research facilities where transuranic (TRU) elements are used. Liquid and solid waste containing TRU elements is generated mainly in the treatment of fuel for critical experiments and in the research of reprocessing and TRU waste management in hot cells and glove boxes. The rational management of TRU wastes is a very important issue not only for NUCEF but also for Japan. An integrated TRU waste management system is being developed with NUCEF as the test bed. The basic policy for establishing the system is to classifymore » wastes by TRU concentration, to reduce waste volume, and to maximize reuse of TRU elements. The principal approach of the development program is to apply the outcomes of the research carried out in NUCEF. Key technologies are TRU measurement for classification of solid wastes and TRU separation and volume reduction for organic and aqueous wastes. Some technologies required for treating the wastes specific to the research activities in NUCEF need further development. Specifically, the separation and stabilization technologies for americium recovery from concentrated aqueous waste, which is generated in dissolution of mixed oxide when preparing fuel for critical experiments, needs further research.« less

5 CFR 430.303 - Definitions.

Code of Federal Regulations, 2013 CFR

2013-01-01

..., including customers and employees. Critical element means a key component of an executive's work that.... Performance management system means the framework of policies and practices that an agency establishes under..., developing, evaluating, and rewarding both individual and organizational performance and for using resulting...

5 CFR 430.303 - Definitions.

Code of Federal Regulations, 2014 CFR

2014-01-01

..., including customers and employees. Critical element means a key component of an executive's work that.... Performance management system means the framework of policies and practices that an agency establishes under..., developing, evaluating, and rewarding both individual and organizational performance and for using resulting...

5 CFR 430.303 - Definitions.

Code of Federal Regulations, 2012 CFR

2012-01-01

..., including customers and employees. Critical element means a key component of an executive's work that.... Performance management system means the framework of policies and practices that an agency establishes under..., developing, evaluating, and rewarding both individual and organizational performance and for using resulting...

REGULATED CONTAMINANTS IN DRINKING WATER

EPA Science Inventory

Safe drinking water is critical to protecting human health. More than 260 million Americans rely on the safety of tap water provided by water systems that comply with national drinking water standards. EPA's strategy for ensuring safe drinking water includes four key elements, ...

Renewal Processes in the Critical Brain

NASA Astrophysics Data System (ADS)

Allegrini, Paolo; Paradisi, Paolo; Menicucci, Danilo; Gemignani, Angelo

We describe herein a multidisciplinary research, as it developes and applies concepts of the theory of complexity, in turn stemming from recent advancements of statistical physics, onto cognitive neuroscience. We discuss (define) complexity, and how the human brain is a paradigm of it. We discuss how the hypothesis of brain activity dynamically behaving as a critical system is taking momentum in literature, then we focus on a feature of critical systems (hence of the brain), which is the intermittent passage between metastable states, marked by events, locally resetting the memory, but giving rise to correlation functions with infinite correlation times. The events, extracted from multi-channel ElectroEncephaloGrams, mark (are interpreted as) a birth/death process of cooperation, namely of system elements being recruited into collective states. Finally we discuss a recently discovered form of control (in the form of a new Linear Response Theory), that allows an optimized information transmission between complex systems, named Complexity Matching.

A Case Study of Non-Functional Requirements and Continuous Improvement at a National Communications System Contractor

ERIC Educational Resources Information Center

Douglas, Volney L. R.

2010-01-01

National communications systems (NCS) are critical elements of a government's infrastructure. Limited improvements to the non-functional requirements (NFR) of NCS have caused issues during national emergencies such as 9/11 and Hurricane Katrina. The literature indicates that these issues result from a deficiency in understanding the roles NFRs and…

Governance, Management and Accountability: The Experience of the School System in the English-Speaking Caribbean Countries

ERIC Educational Resources Information Center

Hutton, Disraeli M.

2015-01-01

This paper seeks to explore the implementation of three of the critical elements required to improve performance in the education system: governance, accountability and management. The paper examines the education reform processes conducted by five Caribbean countries: Jamaica, Cayman Islands, Guyana, Belize, Trinidad and Tobago, along with those…

5 CFR 430.203 - Definitions.

Code of Federal Regulations, 2011 CFR

2011-01-01

... aspect of individual, team, or organizational performance that is not a critical or non-critical element..., or organizational performance, exclusive of a critical element, that is used in assigning a summary... Administrative Personnel OFFICE OF PERSONNEL MANAGEMENT CIVIL SERVICE REGULATIONS PERFORMANCE MANAGEMENT...

Systematic risk assessment methodology for critical infrastructure elements - Oil and Gas subsectors

NASA Astrophysics Data System (ADS)

Gheorghiu, A.-D.; Ozunu, A.

2012-04-01

The concern for the protection of critical infrastructure has been rapidly growing in the last few years in Europe. The level of knowledge and preparedness in this field is beginning to develop in a lawfully organized manner, for the identification and designation of critical infrastructure elements of national and European interest. Oil and gas production, refining, treatment, storage and transmission by pipelines facilities, are considered European critical infrastructure sectors, as per Annex I of the Council Directive 2008/114/EC of 8 December 2008 on the identification and designation of European critical infrastructures and the assessment of the need to improve their protection. Besides identifying European and national critical infrastructure elements, member states also need to perform a risk analysis for these infrastructure items, as stated in Annex II of the above mentioned Directive. In the field of risk assessment, there are a series of acknowledged and successfully used methods in the world, but not all hazard identification and assessment methods and techniques are suitable for a given site, situation, or type of hazard. As Theoharidou, M. et al. noted (Theoharidou, M., P. Kotzanikolaou, and D. Gritzalis 2009. Risk-Based Criticality Analysis. In Critical Infrastructure Protection III. Proceedings. Third Annual IFIP WG 11.10 International Conference on Critical Infrastructure Protection. Hanover, New Hampshire, USA, March 23-25, 2009: revised selected papers, edited by C. Palmer and S. Shenoi, 35-49. Berlin: Springer.), despite the wealth of knowledge already created, there is a need for simple, feasible, and standardized criticality analyses. The proposed systematic risk assessment methodology includes three basic steps: the first step (preliminary analysis) includes the identification of hazards (including possible natural hazards) for each installation/section within a given site, followed by a criterial analysis and then a detailed analysis step. The criterial evaluation is used as a ranking system in order to establish the priorities for the detailed risk assessment. This criterial analysis stage is necessary because the total number of installations and sections on a site can be quite large. As not all installations and sections on a site contribute significantly to the risk of a major accident occurring, it is not efficient to include all installations and sections in the detailed risk assessment, which can be time and resource consuming. The selected installations are then taken into consideration in the detailed risk assessment, which is the third step of the systematic risk assessment methodology. Following this step, conclusions can be drawn related to the overall risk characteristics of the site. The proposed methodology can as such be successfully applied to the assessment of risk related to critical infrastructure elements falling under the energy sector of Critical Infrastructure, mainly the sub-sectors oil and gas. Key words: Systematic risk assessment, criterial analysis, energy sector critical infrastructure elements

Mission and Safety Critical (MASC) plans for the MASC Kernel simulation

NASA Technical Reports Server (NTRS)

1991-01-01

This report discusses a prototype for Mission and Safety Critical (MASC) kernel simulation which explains the intended approach and how the simulation will be used. Smalltalk is chosen for the simulation because of usefulness in quickly building working models of the systems and its object-oriented approach to software. A scenario is also introduced to give details about how the simulation works. The eventual system will be a fully object-oriented one implemented in Ada via Dragoon. To implement the simulation, a scenario using elements typical of those in the Space Station, was created.

Critical dimension control using ultrashort laser for improving wafer critical dimension uniformity

NASA Astrophysics Data System (ADS)

Avizemer, Dan; Sharoni, Ofir; Oshemkov, Sergey; Cohen, Avi; Dayan, Asaf; Khurana, Ranjan; Kewley, Dave

2015-07-01

Requirements for control of critical dimension (CD) become more demanding as the integrated circuit (IC) feature size specifications become tighter and tighter. Critical dimension control, also known as CDC, is a well-known laser-based process in the IC industry that has proven to be robust, repeatable, and efficient in adjusting wafer CD uniformity (CDU) [Proc. SPIE 6152, 615225 (2006)]. The process involves locally and selectively attenuating the deep ultraviolet light which goes through the photomask to the wafer. The input data for the CDC process in the wafer fab is typically taken from wafer CDU data, which is measured by metrology tools such as wafer-critical dimension-scanning electron microscopy (CD-SEM), wafer optical scatterometry, or wafer level CD (WLCD). The CD correction process uses the CDU data in order to create an attenuation correction contour, which is later applied by the in-situ ultrashort laser system of the CDC to locally change the transmission of the photomask. The ultrashort pulsed laser system creates small, partially scattered, Shade-In-Elements (also known as pixels) by focusing the laser beam inside the quartz bulk of the photomask. This results in the formation of a localized, intravolume, quartz modified area, which has a different refractive index than the quartz bulk itself. The CDC process flow for improving wafer CDU in a wafer fab with detailed explanations of the shading elements formation inside the quartz by the ultrashort pulsed laser is reviewed.

Vibration Propagation of Gear Dynamics in a Gear-Bearing-Housing System Using Mathematical Modeling and Finite Element Analysis

NASA Technical Reports Server (NTRS)

Parker, Robert G.; Guo, Yi; Eritenel, Tugan; Ericson, Tristan M.

2012-01-01

Vibration and noise caused by gear dynamics at the meshing teeth propagate through power transmission components to the surrounding environment. This study is devoted to developing computational tools to investigate the vibro-acoustic propagation of gear dynamics through a gearbox using different bearings. Detailed finite element/contact mechanics and boundary element models of the gear/bearing/housing system are established to compute the system vibration and noise propagation. Both vibration and acoustic models are validated by experiments including the vibration modal testing and sound field measurements. The effectiveness of each bearing type to disrupt vibration propagation is speed-dependent. Housing plays an important role in noise radiation .It, however, has limited effects on gear dynamics. Bearings are critical components in drivetrains. Accurate modeling of rolling element bearings is essential to assess vibration and noise of drivetrain systems. This study also seeks to fully describe the vibro-acoustic propagation of gear dynamics through a power-transmission system using rolling element and fluid film wave bearings. Fluid film wave bearings, which have higher damping than rolling element bearings, could offer an energy dissipation mechanism that reduces the gearbox noise. The effectiveness of each bearing type to disrupt vibration propagation in explored using multi-body computational models. These models include gears, shafts, rolling element and fluid film wave bearings, and the housing. Radiated noise is mapped from the gearbox surface to surrounding environment. The effectiveness of rolling element and fluid film wave bearings in breaking the vibro-acoustic propagation path from the gear to the housing is investigated.

A concise guide for the determination of less-studied technology-critical elements (Nb, Ta, Ga, In, Ge, Te) by inductively coupled plasma mass spectrometry in environmental samples

NASA Astrophysics Data System (ADS)

Filella, Montserrat; Rodushkin, Ilia

2018-03-01

There is an increasing demand for analytical techniques able to measure so-called 'technology-critical elements', a set of chemical elements increasingly used in technological applications, in environmental matrices. Nowadays, inductively coupled plasma-mass spectrometry (ICP-MS) has become the technique of choice for measuring trace element concentrations. However, its application is often less straightforward than often assumed. The hints and drawbacks of ICP-MS application to the measurement of a set of less-studied technology-critical elements (Nb, Ta, Ga, In, Ge and Te) is discussed here and concise guidelines given.

40 CFR 86.1803-01 - Definitions.

Code of Federal Regulations, 2014 CFR

2014-07-01

.... Auxiliary Emission Control Device (AECD) means any element of design which senses temperature, vehicle speed.... Critical emission-related components are those components which are designed primarily for emission control... control system is a unique group of emission control devices, auxiliary emission control devices, engine...

ARSENIC DESORPTION FROM DISTRIBUTION SYSTEM SOLIDS

EPA Science Inventory

Due to the recent reduction of the maximum contaminant level (MCL)of arsenic, eliminating possible human exposure has become increasingly critical. Research has suggested that consumer taps could be a likely source of human exposure to this harmful element. This is due to arsenic...

Special Issue: Troubled Family Interactions and Group Intervention.

ERIC Educational Resources Information Center

West, John D.; Kirby, Jonell, Eds.

1981-01-01

Examines the view that individual pathologies and problems are manifestations of family dysfunctions. The interdependence of family members is the critical element in the family group therapy process. Intervention involves the disruption of the dynamic balance maintained by the family system. (RC)

Dynamic Analysis of Geared Rotors by Finite Elements

NASA Technical Reports Server (NTRS)

Kahraman, A.; Ozguven, H. Nevzat; Houser, D. R.; Zakrajsek, J. J.

1992-01-01

A finite element model of a geared rotor system on flexible bearings has been developed. The model includes the rotary inertia of on shaft elements, the axial loading on shafts, flexibility and damping of bearings, material damping of shafts and the stiffness and the damping of gear mesh. The coupling between the torsional and transverse vibrations of gears were considered in the model. A constant mesh stiffness was assumed. The analysis procedure can be used for forced vibration analysis geared rotors by calculating the critical speeds and determining the response of any point on the shafts to mass unbalances, geometric eccentricities of gears, and displacement transmission error excitation at the mesh point. The dynamic mesh forces due to these excitations can also be calculated. The model has been applied to several systems for the demonstration of its accuracy and for studying the effect of bearing compliances on system dynamics.

Association of Serum Concentration of Different Trace Elements with Biomarkers of Systemic Oxidant Status in Dairy Cattle.

PubMed

Abuelo, Angel; Hernandez, Joaquín; Alves-Nores, Víctor; Benedito, José L; Castillo, Cristina

2016-12-01

There has been some recent criticism about the reliability of the assays commonly used to measure oxidant status in cattle, because some recent publications suggested that the concentration of different trace elements influences the results of these assays. The aim of this study was to test the correlation in 502 bovine serum samples between the concentration of several trace elements (Br, Co, Cr, Cu, Fe, I, Mn, Mo, Ni, Se, Sr, V and Zn) and markers of oxidant status (reactive oxygen species (ROS) and total serum antioxidant capacity (SAC)). The Oxidative Stress index (OSi) was also calculated as ROS/SAC. Some significant correlations were found, although weak (|ρ| < 0.50). Therefore, the relationships observed might be attributed to the different pro- and antioxidant effect of the different elements rather than to the assays detecting these elements instead of the oxidised molecules or total antioxidant potential, respectively. The OSi was poorly correlated (|ρ| ≤ 0.36) with the concentration of the studied trace elements, and therefore, its use is recommended to assess shifts in the systemic redox balance.

Feasibility study of an Integrated Program for Aerospace-vehicle Design (IPAD) system. Volume 6: Implementation schedule, development costs, operational costs, benefit assessment, impact on company organization, spin-off assessment, phase 1, tasks 3 to 8

NASA Technical Reports Server (NTRS)

Garrocq, C. A.; Hurley, M. J.; Dublin, M.

1973-01-01

A baseline implementation plan, including alternative implementation approaches for critical software elements and variants to the plan, was developed. The basic philosophy was aimed at: (1) a progressive release of capability for three major computing systems, (2) an end product that was a working tool, (3) giving participation to industry, government agencies, and universities, and (4) emphasizing the development of critical elements of the IPAD framework software. The results of these tasks indicate an IPAD first release capability 45 months after go-ahead, a five year total implementation schedule, and a total developmental cost of 2027 man-months and 1074 computer hours. Several areas of operational cost increases were identified mainly due to the impact of additional equipment needed and additional computer overhead. The benefits of an IPAD system were related mainly to potential savings in engineering man-hours, reduction of design-cycle calendar time, and indirect upgrading of product quality and performance.

5 CFR 432.103 - Definitions.

Code of Federal Regulations, 2010 CFR

2010-01-01

... performance above “unacceptable” in the critical element(s) at issue. (b) Critical element means a work... to the work. (h) Unacceptable performance means performance of an employee that fails to meet... Administrative Personnel OFFICE OF PERSONNEL MANAGEMENT CIVIL SERVICE REGULATIONS PERFORMANCE BASED REDUCTION IN...

Sall4-Gli3 system in early limb progenitors is essential for the development of limb skeletal elements.

PubMed

Akiyama, Ryutaro; Kawakami, Hiroko; Wong, Julia; Oishi, Isao; Nishinakamura, Ryuichi; Kawakami, Yasuhiko

2015-04-21

Limb skeletal elements originate from the limb progenitor cells, which undergo expansion and patterning to develop each skeletal element. Posterior-distal skeletal elements, such as the ulna/fibula and posterior digits develop in a Sonic hedgehog (Shh)-dependent manner. However, it is poorly understood how anterior-proximal elements, such as the humerus/femur, the radius/tibia and the anterior digits, are developed. Here we show that the zinc finger factors Sall4 and Gli3 cooperate for proper development of the anterior-proximal skeletal elements and also function upstream of Shh-dependent posterior skeletal element development. Conditional inactivation of Sall4 in the mesoderm before limb outgrowth caused severe defects in the anterior-proximal skeletal elements in the hindlimb. We found that Gli3 expression is reduced in Sall4 mutant hindlimbs, but not in forelimbs. This reduction caused posteriorization of nascent hindlimb buds, which is correlated with a loss of anterior digits. In proximal development, Sall4 integrates Gli3 and the Plzf-Hox system, in addition to proliferative expansion of cells in the mesenchymal core of nascent hindlimb buds. Whereas forelimbs developed normally in Sall4 mutants, further genetic analysis identified that the Sall4-Gli3 system is a common regulator of the early limb progenitor cells in both forelimbs and hindlimbs. The Sall4-Gli3 system also functions upstream of the Shh-expressing ZPA and the Fgf8-expressing AER in fore- and hindlimbs. Therefore, our study identified a critical role of the Sall4-Gli3 system at the early steps of limb development for proper development of the appendicular skeletal elements.

Reliability Analysis of Large Commercial Vessel Engine Room Automation Systems. Volume 1. Results

DTIC Science & Technology

1982-11-01

analyzing the engine room automiations systems on two steam vessels and one diesel vessel, conducting a criticality evaluation, pre- paring...of automated engine room systems,° the effect of *. maintenance was also to be considered, as was the human inter- face and backup. Besides being...designed to replace the human element, the systems periorm more efficiently than the human watchstander. But as with any system, there is no such thing as

Study on vibration characteristics of the shaft system for a dredging pump based on FEM

NASA Astrophysics Data System (ADS)

Zhai, L. M.; Qin, L.; Liu, C. Y.; Liu, X.; He, L. Y.; He, Y.; Wang, Z. W.

2012-11-01

The dynamic characteristics of the shaft system for a dredging pump were studied with the Finite Element Method (FEM) by SAMCEF ROTOR. At first, the influence of the fluid-solid coupling interaction of mud water and impeller, water sealing and pump shaft on the lateral critical speeds were analyzed. The results indicated that the mud water must be taken into consideration, while the water sealing need not to. Then the effects of radial and thrust rolling bearings on the lateral critical speeds were discussed, which shows that the radial bearing close to the impeller has greatest impact on the 1st order critical speed. At last, the upper and lower limits of the critical speeds of lateral, axial and torsional vibration were calculated. The rated speed of the dredging pump was far less than the predicted critical speed, which can ensure the safe operation of the unit. Each vibration mode is also shown in this paper. This dynamic analysis method offers some reference value on the research of vibration and stability of the shaft system in dredging pump.

Stress Analysis of B-52B and B-52H Air-Launching Systems Failure-Critical Structural Components

NASA Technical Reports Server (NTRS)

Ko, William L.

2005-01-01

The operational life analysis of any airborne failure-critical structural component requires the stress-load equation, which relates the applied load to the maximum tangential tensile stress at the critical stress point. The failure-critical structural components identified are the B-52B Pegasus pylon adapter shackles, B-52B Pegasus pylon hooks, B-52H airplane pylon hooks, B-52H airplane front fittings, B-52H airplane rear pylon fitting, and the B-52H airplane pylon lower sway brace. Finite-element stress analysis was performed on the said structural components, and the critical stress point was located and the stress-load equation was established for each failure-critical structural component. The ultimate load, yield load, and proof load needed for operational life analysis were established for each failure-critical structural component.

Determination of the critical plane and durability estimation for a multiaxial cyclic loading

NASA Astrophysics Data System (ADS)

Burago, N. G.; Nikitin, A. D.; Nikitin, I. S.; Yakushev, V. L.

2018-03-01

An analytical procedure is proposed to determine the critical plane orientation according to the Findley criterion for the multiaxial cyclic loading. The cases of in-phase and anti-phase cyclic loading are considered. Calculations of the stress state are carried out for the system of the gas turbine engine compressor disk and blades for flight loading cycles. The formulas obtained are used for estimations of the fatigue durability of this essential element of structure.

Probabilistic Structural Analysis Methods for select space propulsion system components (PSAM). Volume 2: Literature surveys of critical Space Shuttle main engine components

NASA Technical Reports Server (NTRS)

Rajagopal, K. R.

1992-01-01

The technical effort and computer code development is summarized. Several formulations for Probabilistic Finite Element Analysis (PFEA) are described with emphasis on the selected formulation. The strategies being implemented in the first-version computer code to perform linear, elastic PFEA is described. The results of a series of select Space Shuttle Main Engine (SSME) component surveys are presented. These results identify the critical components and provide the information necessary for probabilistic structural analysis. Volume 2 is a summary of critical SSME components.

LIMS user acceptance testing.

PubMed

Klein, Corbett S

2003-01-01

Laboratory Information Management Systems (LIMS) play a key role in the pharmaceutical industry. Thorough and accurate validation of such systems is critical and is a regulatory requirement. LIMS user acceptance testing is one aspect of this testing and enables the user to make a decision to accept or reject implementation of the system. This paper discusses key elements in facilitating the development and execution of a LIMS User Acceptance Test Plan (UATP).

Task allocation in a distributed computing system

NASA Technical Reports Server (NTRS)

Seward, Walter D.

1987-01-01

A conceptual framework is examined for task allocation in distributed systems. Application and computing system parameters critical to task allocation decision processes are discussed. Task allocation techniques are addressed which focus on achieving a balance in the load distribution among the system's processors. Equalization of computing load among the processing elements is the goal. Examples of system performance are presented for specific applications. Both static and dynamic allocation of tasks are considered and system performance is evaluated using different task allocation methodologies.

Critical Thinking and Intelligence Analysis

DTIC Science & Technology

2007-03-01

assess such systems – terrorist networks are but one example. Additionally, as sociologist Emile Durkheim observes, the combinations of elements...University Press, 99), 0. Cited hereafter as Jervis, System Effects. Emile Durkheim , The Rules of Sociological Method (Glencoe, IL: Free Press...Puzzles. New York, NY: Main Street, 2005. Durkheim , Emile . The Rules of Sociological Method. Glencoe, IL: Free Press, 1938. Eco, Umberto, and

Computer Resources Handbook for Flight Critical Systems.

DTIC Science & Technology

1985-01-01

8183 UNCLASSIFIED F /G 1 /3 NLllEEEEEEEEEEEE Illll lflflflflfl Illlfll..lflll EIEEIhEEIIIIII llElfllfllflfllfll .flflflflflflflflflflflll llEEEEEEllEII...Requiring Simulation .... ............. ... 114 6-4 Typical Transition Elements of Care III. ...... ............ 116 D- 1 F -16 Digital Flight Control...following forms: 1 . By reference to MIL- F -9490(for flight control systems); 2. By reference, with tailoring if required, to a Federal Aviation Regulation

The Social Science Observation Record: A Guide for Pre-service and In-service Teachers Participating in Microteaching.

ERIC Educational Resources Information Center

Casteel, J. Doyle; Stahl, Robert J.

Systematic and reliable feedback are critical elements of microteaching. One system whereby pre-service and in-service teachers may obtain systematic and reliable feedback during microteaching is called the Social Science Observation Record (SSOR). This monograph is intended to meet three purposes: (1) To explain the SSOR as a verbal system for…

A Behavioural Approach to Understanding Semi-Subsistence Farmers' Technology Adoption Decisions: The Case of Improved Paddy-Prawn System in Indonesia

ERIC Educational Resources Information Center

Sambodo, Leonardo A. A. T.; Nuthall, Peter L.

2010-01-01

Purpose: This study traced the origins of subsistence Farmers' technology adoption attitudes and extracted the critical elements in their decision making systems. Design/Methodology/Approach: The analysis was structured using a model based on the Theory of Planned Behaviour (TPB). The role of a "bargaining process" was particularly…

Software Innovation in a Mission Critical Environment

NASA Technical Reports Server (NTRS)

Fredrickson, Steven

2015-01-01

Operating in mission-critical environments requires trusted solutions, and the preference for "tried and true" approaches presents a potential barrier to infusing innovation into mission-critical systems. This presentation explores opportunities to overcome this barrier in the software domain. It outlines specific areas of innovation in software development achieved by the Johnson Space Center (JSC) Engineering Directorate in support of NASA's major human spaceflight programs, including International Space Station, Multi-Purpose Crew Vehicle (Orion), and Commercial Crew Programs. Software engineering teams at JSC work with hardware developers, mission planners, and system operators to integrate flight vehicles, habitats, robotics, and other spacecraft elements for genuinely mission critical applications. The innovations described, including the use of NASA Core Flight Software and its associated software tool chain, can lead to software that is more affordable, more reliable, better modelled, more flexible, more easily maintained, better tested, and enabling of automation.

A Software Safety Risk Taxonomy for Use in Retrospective Safety Cases

NASA Technical Reports Server (NTRS)

Hill, Janice L.

2007-01-01

Safety standards contain technical and process-oriented safely requirements. The best time to include these requirements is early in the development lifecycle of the system. When software safety requirements are levied on a legacy system after the fact, a retrospective safety case will need to be constructed for the software in the system. This can be a difficult task because there may be few to no art facts available to show compliance to the software safely requirements. The risks associated with not meeting safely requirements in a legacy safely-critical computer system must be addressed to give confidence for reuse. This paper introduces a proposal for a software safely risk taxonomy for legacy safely-critical computer systems, by specializing the Software Engineering Institute's 'Software Development Risk Taxonomy' with safely elements and attributes.

Upset Characterization of the PowerPC405 Hard-core Processor Embedded in Virtex-II Pro Field Programmable Gate Arrays

NASA Technical Reports Server (NTRS)

Swift, Gary M.; Allen, Gregory S.; Farmanesh, Farhad; George, Jeffrey; Petrick, David J.; Chayab, Fayez

2006-01-01

Shown in this presentation are recent results for the upset susceptibility of the various types of memory elements in the embedded PowerPC405 in the Xilinx V2P40 FPGA. For critical flight designs where configuration upsets are mitigated effectively through appropriate design triplication and configuration scrubbing, these upsets of processor elements can dominate the system error rate. Data from irradiations with both protons and heavy ions are given and compared using available models.

Reaping the benefits of an open systems approach: getting the commercial approach right

NASA Astrophysics Data System (ADS)

Pearson, Gavin; Dawe, Tony; Stubbs, Peter; Worthington, Olwen

2016-05-01

Critical to reaping the benefits of an Open System Approach within Defence, or any other sector, is the ability to design the appropriate commercial model (or framework). This paper reports on the development and testing of a commercial strategy decision support tool. The tool set comprises a number of elements, including a process model, and provides business intelligence insights into likely supplier behaviour. The tool has been developed by subject matter experts and has been tested with a number of UK Defence procurement teams. The paper will present the commercial model framework, the elements of the toolset and the results of testing.

Adaptive critic autopilot design of bank-to-turn missiles using fuzzy basis function networks.

PubMed

Lin, Chuan-Kai

2005-04-01

A new adaptive critic autopilot design for bank-to-turn missiles is presented. In this paper, the architecture of adaptive critic learning scheme contains a fuzzy-basis-function-network based associative search element (ASE), which is employed to approximate nonlinear and complex functions of bank-to-turn missiles, and an adaptive critic element (ACE) generating the reinforcement signal to tune the associative search element. In the design of the adaptive critic autopilot, the control law receives signals from a fixed gain controller, an ASE and an adaptive robust element, which can eliminate approximation errors and disturbances. Traditional adaptive critic reinforcement learning is the problem faced by an agent that must learn behavior through trial-and-error interactions with a dynamic environment, however, the proposed tuning algorithm can significantly shorten the learning time by online tuning all parameters of fuzzy basis functions and weights of ASE and ACE. Moreover, the weight updating law derived from the Lyapunov stability theory is capable of guaranteeing both tracking performance and stability. Computer simulation results confirm the effectiveness of the proposed adaptive critic autopilot.

Critical elements in sediment-hosted deposits (clastic-dominated Zn-Pb-Ag, Mississippi Valley-type Zn-Pb, sedimentary rock-hosted Stratiform Cu, and carbonate-hosted Polymetallic Deposits): A review: Chapter 12

USGS Publications Warehouse

Marsh, Erin; Hitzman, Murray W.; Leach, David L.

2016-01-01

Some sediment-hosted base metal deposits, specifically the clastic-dominated (CD) Zn-Pb deposits, carbonate-hosted Mississippi Valley-type (MVT) deposits, sedimentary-rock hosted stratiform copper deposits, and carbonate-hosted polymetallic (“Kipushi type”) deposits, are or have been important sources of critical elements including Co, Ga, Ge, and Re. The generally poor data concerning trace element concentrations in these types of sediment-hosted ores suggest that there may be economically important concentrations of critical elements yet to be recognized.

2011 Annual Criticality Safety Program Performance Summary

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

Andrea Hoffman

The 2011 review of the INL Criticality Safety Program has determined that the program is robust and effective. The review was prepared for, and fulfills Contract Data Requirements List (CDRL) item H.20, 'Annual Criticality Safety Program performance summary that includes the status of assessments, issues, corrective actions, infractions, requirements management, training, and programmatic support.' This performance summary addresses the status of these important elements of the INL Criticality Safety Program. Assessments - Assessments in 2011 were planned and scheduled. The scheduled assessments included a Criticality Safety Program Effectiveness Review, Criticality Control Area Inspections, a Protection of Controlled Unclassified Information Inspection,more » an Assessment of Criticality Safety SQA, and this management assessment of the Criticality Safety Program. All of the assessments were completed with the exception of the 'Effectiveness Review' for SSPSF, which was delayed due to emerging work. Although minor issues were identified in the assessments, no issues or combination of issues indicated that the INL Criticality Safety Program was ineffective. The identification of issues demonstrates the importance of an assessment program to the overall health and effectiveness of the INL Criticality Safety Program. Issues and Corrective Actions - There are relatively few criticality safety related issues in the Laboratory ICAMS system. Most were identified by Criticality Safety Program assessments. No issues indicate ineffectiveness in the INL Criticality Safety Program. All of the issues are being worked and there are no imminent criticality concerns. Infractions - There was one criticality safety related violation in 2011. On January 18, 2011, it was discovered that a fuel plate bundle in the Nuclear Materials Inspection and Storage (NMIS) facility exceeded the fissionable mass limit, resulting in a technical safety requirement (TSR) violation. The TSR limits fuel plate bundles to 1085 grams U-235, which is the maximum loading of an ATR fuel element. The overloaded fuel plate bundle contained 1097 grams U-235 and was assembled under an 1100 gram U-235 limit in 1982. In 2003, the limit was reduced to 1085 grams citing a new criticality safety evaluation for ATR fuel elements. The fuel plate bundle inventories were not checked for compliance prior to implementing the reduced limit. A subsequent review of the NMIS inventory did not identify further violations. Requirements Management - The INL Criticality Safety program is organized and well documented. The source requirements for the INL Criticality Safety Program are from 10 CFR 830.204, DOE Order 420.1B, Chapter III, 'Nuclear Criticality Safety,' ANSI/ANS 8-series Industry Standards, and DOE Standards. These source requirements are documented in LRD-18001, 'INL Criticality Safety Program Requirements Manual.' The majority of the criticality safety source requirements are contained in DOE Order 420.1B because it invokes all of the ANSI/ANS 8-Series Standards. DOE Order 420.1B also invokes several DOE Standards, including DOE-STD-3007, 'Guidelines for Preparing Criticality Safety Evaluations at Department of Energy Non-Reactor Nuclear Facilities.' DOE Order 420.1B contains requirements for DOE 'Heads of Field Elements' to approve the criticality safety program and specific elements of the program, namely, the qualification of criticality staff and the method for preparing criticality safety evaluations. This was accomplished by the approval of SAR-400, 'INL Standardized Nuclear Safety Basis Manual,' Chapter 6, 'Prevention of Inadvertent Criticality.' Chapter 6 of SAR-400 contains sufficient detail and/or reference to the specific DOE and contractor documents that adequately describe the INL Criticality Safety Program per the elements specified in DOE Order 420.1B. The Safety Evaluation Report for SAR-400 specifically recognizes that the approval of SAR-400 approves the INL Criticality Safety Program. No new source requirements were released in 2011. A revision to LRD-18001 is planned for 2012 to clarify design requirements for criticality alarms. Training - Criticality Safety Engineering has developed training and provides training for many employee positions, including fissionable material handlers, facility managers, criticality safety officers, firefighters, and criticality safety engineers. Criticality safety training at the INL is a program strength. A revision to the training module developed in 2010 to supplement MFC certified fissionable material handlers (operators) training was prepared and presented in August of 2011. This training, 'Applied Science of Criticality Safety,' builds upon existing training and gives operators a better understanding of how their criticality controls are derived. Improvements to 00INL189, 'INL Criticality Safety Principles' are planned for 2012 to strengthen fissionable material handler training.« less

Stability of numerical integration techniques for transient rotor dynamics

NASA Technical Reports Server (NTRS)

Kascak, A. F.

1977-01-01

A finite element model of a rotor bearing system was analyzed to determine the stability limits of the forward, backward, and centered Euler; Runge-Kutta; Milne; and Adams numerical integration techniques. The analysis concludes that the highest frequency mode determines the maximum time step for a stable solution. Thus, the number of mass elements should be minimized. Increasing the damping can sometimes cause numerical instability. For a uniform shaft, with 10 mass elements, operating at approximately the first critical speed, the maximum time step for the Runge-Kutta, Milne, and Adams methods is that which corresponds to approximately 1 degree of shaft movement. This is independent of rotor dimensions.

System performance testing of the DSN radio science system, Mark 3-78

NASA Technical Reports Server (NTRS)

Berman, A. L.; Mehta, J. S.

1978-01-01

System performance tests are required to evaluate system performance following initial system implementation and subsequent modification, and to validate system performance prior to actual operational usage. Non-real-time end-to-end Radio Science system performance tests are described that are based on the comparison of open-loop radio science data to equivalent closed-loop radio metric data, as well as an abbreviated Radio Science real-time system performance test that validates critical Radio Science System elements at the Deep Space Station prior to actual operational usage.

P3 DESIGN OF A NATIONAL ELECTRONICS PRODUCT REUSE AND RECYCLING SYSTEM

EPA Science Inventory

Material and resource conservation are critical to sustainability; and, the ability to efficiently and effectively recover old products for reuse and recycle is an essential element in these conservation efforts. In California alone, it has been estimated that 10,000 computers a...

On the Spiritual Element in Arts Education.

ERIC Educational Resources Information Center

Abbs, Peter

1995-01-01

Attempts a redefinition of spirituality and an incorporation of this into art education. Argues that symbolic and spiritual consciousness plays a crucial role in the works of artists as disparate as William Blake and Frida Kahlo. Criticizes the preeminence of scientific theory as a modern belief system. (MJP)

Design and evaluation of a failure detection and isolation algorithm for restructurable control systems

NASA Technical Reports Server (NTRS)

Weiss, Jerold L.; Hsu, John Y.

1986-01-01

The use of a decentralized approach to failure detection and isolation for use in restructurable control systems is examined. This work has produced: (1) A method for evaluating fundamental limits to FDI performance; (2) Application using flight recorded data; (3) A working control element FDI system with maximal sensitivity to critical control element failures; (4) Extensive testing on realistic simulations; and (5) A detailed design methodology involving parameter optimization (with respect to model uncertainties) and sensitivity analyses. This project has concentrated on detection and isolation of generic control element failures since these failures frequently lead to emergency conditions and since knowledge of remaining control authority is essential for control system redesign. The failures are generic in the sense that no temporal failure signature information was assumed. Thus, various forms of functional failures are treated in a unified fashion. Such a treatment results in a robust FDI system (i.e., one that covers all failure modes) but sacrifices some performance when detailed failure signature information is known, useful, and employed properly. It was assumed throughout that all sensors are validated (i.e., contain only in-spec errors) and that only the first failure of a single control element needs to be detected and isolated. The FDI system which has been developed will handle a class of multiple failures.

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

Saha, Sourabh K.

Although geometric imperfections have a detrimental effect on buckling, imperfection sensitivity has not been well studied in the past during design of sinusoidal micro and nano-scale structures via wrinkling of supported thin films. This is likely because one is more interested in predicting the shape/size of the resultant patterns than the buckling bifurcation onset strain during fabrication of such wrinkled structures. Herein, I have demonstrated that even modest geometric imperfections alter the final wrinkled mode shapes via the mode locking phenomenon wherein the imperfection mode grows in exclusion to the natural mode of the system. To study the effect ofmore » imperfections on mode locking, I have (i) developed a finite element mesh perturbation scheme to generate arbitrary geometric imperfections in the system and (ii) performed a parametric study via finite element methods to link the amplitude and period of the sinusoidal imperfections to the observed wrinkle mode shape and size. Based on this, a non-dimensional geometric parameter has been identified that characterizes the effect of imperfection on the mode locking phenomenon – the equivalent imperfection size. An upper limit for this equivalent imperfection size has been identified via a combination of analytical and finite element modeling. During compression of supported thin films, the system gets “locked” into the imperfection mode if its equivalent imperfection size is above this critical limit. For the polydimethylsiloxane/glass bilayer with a wrinkle period of 2 µm, this mode lock-in limit corresponds to an imperfection amplitude of 32 nm for an imperfection period of 5 µm and 8 nm for an imperfection period of 0.8 µm. Interestingly, when the non-dimensional critical imperfection size is scaled by the bifurcation onset strain, the scaled critical size depends solely on the ratio of the imperfection to natural periods. Furthermore, the computational data generated here can be generalized beyond the specific natural periods and bilayer systems studied to enable deterministic design of a variety of wrinkled micro and nano-scale structures.« less

Criticality safety evaluation for the Advanced Test Reactor enhanced low enriched uranium fuel elements

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

Montierth, Leland M.

2016-07-19

The Global Threat Reduction Initiative (GTRI) convert program is developing a high uranium density fuel based on a low enriched uranium (LEU) uranium-molybdenum alloy. Testing of prototypic GTRI fuel elements is necessary to demonstrate integrated fuel performance behavior and scale-up of fabrication techniques. GTRI Enhanced LEU Fuel (ELF) elements based on the ATR-Standard Size elements (all plates fueled) are to be fabricated for testing in the Advanced Test Reactor (ATR). While a specific ELF element design will eventually be provided for detailed analyses and in-core testing, this criticality safety evaluation (CSE) is intended to evaluate a hypothetical ELF element designmore » for criticality safety purposes. Existing criticality analyses have analyzed Standard (HEU) ATR elements from which controls have been derived. This CSE documents analysis that determines the reactivity of the hypothetical ELF fuel elements relative to HEU ATR elements and whether the existing HEU ATR element controls bound the ELF element. The initial calculations presented in this CSE analyzed the original ELF design, now referred to as Mod 0.1. In addition, as part of a fuel meat thickness optimization effort for reactor performance, other designs have been evaluated. As of early 2014 the most current conceptual designs are Mk1A and Mk1B, that were previously referred to as conceptual designs Mod 0.10 and Mod 0.11, respectively. Revision 1 evaluates the reactivity of the ATR HEU Mark IV elements for a comparison with the Mark VII elements.« less

Gulf War Air Power Survey. Volume 4. Weapons, Tactics, and Training and Space Operations

DTIC Science & Technology

1993-01-01

situation within their sectors. The socs were the critical element of the integrated battle management system.’" [ DE - LETED]. The Soc personnel...sys- tem. Figure 4 illustrates SAM and radar coverage. Priority was given to the areas critical to the survival of the regime. Figure 5 shows the de ...runways of over 3,659 meters. Figure 7 shows the location of the major Iraqi air bases and de - ployment/dispersal fields as of December 1991. Iraqi air

50 CFR 226.215 - Critical habitat for the North Pacific Right Whale (Eubalaena japonica).

Code of Federal Regulations, 2011 CFR

2011-10-01

... Right Whale (Eubalaena japonica). 226.215 Section 226.215 Wildlife and Fisheries NATIONAL MARINE... DESIGNATED CRITICAL HABITAT § 226.215 Critical habitat for the North Pacific Right Whale (Eubalaena japonica). (a) Primary Constituent Elements. The primary constituent elements of the North Pacific right whale...

50 CFR 226.215 - Critical habitat for the North Pacific Right Whale (Eubalaena japonica).

Code of Federal Regulations, 2012 CFR

2012-10-01

... Right Whale (Eubalaena japonica). 226.215 Section 226.215 Wildlife and Fisheries NATIONAL MARINE... DESIGNATED CRITICAL HABITAT § 226.215 Critical habitat for the North Pacific Right Whale (Eubalaena japonica). (a) Primary Constituent Elements. The primary constituent elements of the North Pacific right whale...

50 CFR 226.215 - Critical habitat for the North Pacific Right Whale (Eubalaena japonica).

Code of Federal Regulations, 2013 CFR

2013-10-01

... Right Whale (Eubalaena japonica). 226.215 Section 226.215 Wildlife and Fisheries NATIONAL MARINE... DESIGNATED CRITICAL HABITAT § 226.215 Critical habitat for the North Pacific Right Whale (Eubalaena japonica). (a) Primary Constituent Elements. The primary constituent elements of the North Pacific right whale...

50 CFR 226.215 - Critical habitat for the North Pacific Right Whale (Eubalaena japonica).

Code of Federal Regulations, 2014 CFR

2014-10-01

... Right Whale (Eubalaena japonica). 226.215 Section 226.215 Wildlife and Fisheries NATIONAL MARINE... DESIGNATED CRITICAL HABITAT § 226.215 Critical habitat for the North Pacific Right Whale (Eubalaena japonica). (a) Primary Constituent Elements. The primary constituent elements of the North Pacific right whale...

50 CFR 226.215 - Critical habitat for the North Pacific Right Whale (Eubalaena japonica).

Code of Federal Regulations, 2010 CFR

2010-10-01

... Right Whale (Eubalaena japonica). 226.215 Section 226.215 Wildlife and Fisheries NATIONAL MARINE... DESIGNATED CRITICAL HABITAT § 226.215 Critical habitat for the North Pacific Right Whale (Eubalaena japonica). (a) Primary Constituent Elements. The primary constituent elements of the North Pacific right whale...

Smart Sensor Demonstration Payload

NASA Technical Reports Server (NTRS)

Schmalzel, John; Bracey, Andrew; Rawls, Stephen; Morris, Jon; Turowski, Mark; Franzl, Richard; Figueroa, Fernando

2010-01-01

Sensors are a critical element to any monitoring, control, and evaluation processes such as those needed to support ground based testing for rocket engine test. Sensor applications involve tens to thousands of sensors; their reliable performance is critical to achieving overall system goals. Many figures of merit are used to describe and evaluate sensor characteristics; for example, sensitivity and linearity. In addition, sensor selection must satisfy many trade-offs among system engineering (SE) requirements to best integrate sensors into complex systems [1]. These SE trades include the familiar constraints of power, signal conditioning, cabling, reliability, and mass, and now include considerations such as spectrum allocation and interference for wireless sensors. Our group at NASA s John C. Stennis Space Center (SSC) works in the broad area of integrated systems health management (ISHM). Core ISHM technologies include smart and intelligent sensors, anomaly detection, root cause analysis, prognosis, and interfaces to operators and other system elements [2]. Sensor technologies are the base fabric that feed data and health information to higher layers. Cost-effective operation of the complement of test stands benefits from technologies and methodologies that contribute to reductions in labor costs, improvements in efficiency, reductions in turn-around times, improved reliability, and other measures. ISHM is an active area of development at SSC because it offers the potential to achieve many of those operational goals [3-5].

Modularity: An Application of General Systems Theory to Military Force Development

DTIC Science & Technology

2005-01-01

1999). Context, modularity, and the cultural constitution of development. In P. Lloyd & C. Fernyhough (Eds.), Lev Vygotsky : Critical assessments...of General Systems Theory to Military Force Development 5a. CONTRACT NUMBER 5b. GRANT NUMBER 5c. PROGRAM ELEMENT NUMBER 6. AUTHOR(S) 5d. PROJECT...Prescribed by ANSI Std Z39-18 MODULARITY: AN APPLICATION OF GENERAL SYSTEMS THEORY TO MILITARY FORCE DEVELOPMENT 279 R SEARCH MODULARITY: AN APPLICATION OF

Quantification of the resource recovery potential of municipal solid waste incineration bottom ashes

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

Allegrini, Elisa, E-mail: elia@env.dtu.dk; Maresca, Alberto; Olsson, Mikael Emil

2014-09-15

Highlights: • Ferrous and non-ferrous metals were quantified in MSWI bottom ashes. • Metal recovery system efficiencies for bottom ashes were estimated. • Total content of critical elements was determined in bottom ash samples. • Post-incineration recovery is not viable for most critical elements. - Abstract: Municipal solid waste incineration (MSWI) plays an important role in many European waste management systems. However, increasing focus on resource criticality has raised concern regarding the possible loss of critical resources through MSWI. The primary form of solid output from waste incinerators is bottom ashes (BAs), which also have important resource potential. Based onmore » a full-scale Danish recovery facility, detailed material and substance flow analyses (MFA and SFA) were carried out, in order to characterise the resource recovery potential of Danish BA: (i) based on historical and experimental data, all individual flows (representing different grain size fractions) within the recovery facility were quantified, (ii) the resource potential of ferrous (Fe) and non-ferrous (NFe) metals as well as rare earth elements (REE) was determined, (iii) recovery efficiencies were quantified for scrap metal and (iv) resource potential variability and recovery efficiencies were quantified based on a range of ashes from different incinerators. Recovery efficiencies for Fe and NFe reached 85% and 61%, respectively, with the resource potential of metals in BA before recovery being 7.2%ww for Fe and 2.2%ww for NFe. Considerable non-recovered resource potential was found in fine fraction (below 2 mm), where approximately 12% of the total NFe potential in the BA were left. REEs were detected in the ashes, but the levels were two or three orders of magnitude lower than typical ore concentrations. The lack of REE enrichment in BAs indicated that the post-incineration recovery of these resources may not be a likely option with current technology. Based on these results, it is recommended to focus on limiting REE-containing products in waste for incineration and improving pre-incineration sorting initiatives for these elements.« less

Towards better monitoring of technology critical elements in Europe: Coupling of natural and anthropogenic cycles.

PubMed

Nuss, Philip; Blengini, Gian Andrea

2018-02-01

The characterization of elemental cycles has a rich history in biogeochemistry. Well known examples include the global carbon cycle, or the cycles of the 'grand nutrients' nitrogen, phosphorus, and sulfur. More recently, efforts have increased to better understand the natural cycling of technology critical elements (TCEs), i.e. elements with a high supply risk and economic importance in the EU. On the other hand, tools such as material-flow analysis (MFA) can help to understand how substances and goods are transported and accumulated in man-made technological systems ('anthroposphere'). However, to date both biogeochemical cycles and MFA studies suffer from narrow system boundaries, failing to fully illustrate relative anthropogenic and natural flow magnitude and the degree to which human activity has perturbed the natural cycling of elements. We discuss important interconnections between natural and anthropogenic cycles and relevant EU raw material dossiers. Increased integration of both cycles could help to better capture the transport and fate of elements in nature including their environmental/human health impacts, highlight potential future material stocks in the anthroposphere (in-use stocks) and in nature (e.g., in soils, tailings, or mining wastes), and estimate anticipated emissions of TCEs to nature in the future (based on dynamic stock modeling). A preliminary assessment of natural versus anthropogenic element fluxes indicates that anthropogenic fluxes induced by the EU-28 of palladium, platinum, and antimony (as a result of materials uses) might be greater than the respective global natural fluxes. Increased combination of MFA and natural cycle data at EU level could help to derive more complete material cycles and initiate a discussion between the research communities of biogeochemists and material flow analysts to more holistically address the issues of sustainable resource management. Copyright © 2017 The Authors. Published by Elsevier B.V. All rights reserved.

Out of Balance—Systemic Iron Homeostasis in Iron-Related Disorders

PubMed Central

Steinbicker, Andrea U.; Muckenthaler, Martina U.

2013-01-01

Iron is an essential element in our daily diet. Most iron is required for the de novo synthesis of red blood cells, where it plays a critical role in oxygen binding to hemoglobin. Thus, iron deficiency causes anemia, a major public health burden worldwide. On the other extreme, iron accumulation in critical organs such as liver, heart, and pancreas causes organ dysfunction due to the generation of oxidative stress. Therefore, systemic iron levels must be tightly balanced. Here we focus on the regulatory role of the hepcidin/ferroportin circuitry as the major regulator of systemic iron homeostasis. We discuss how regulatory cues (e.g., iron, inflammation, or hypoxia) affect the hepcidin response and how impairment of the hepcidin/ferroportin regulatory system causes disorders of iron metabolism. PMID:23917168

The Relationship between Teachers' Views about Cultural Values and Critical Pedagogy

ERIC Educational Resources Information Center

Yilmaz, Kursad; Altinkurt, Yahya; Ozciftci, Elif

2016-01-01

Problem Statement: Known as basic elements directing individuals' lives, cultural values are hidden cultural elements that influence all evaluations and perceptions. Values, in that sense, are elements individuals are aware of and provide the answer to the "what should I do?" feeling (Schein, 1992). Critical pedagogy is a project based…

A Mobile Game-Based English Vocabulary Practice System Based on Portfolio Analysis

ERIC Educational Resources Information Center

Wu, Ting-Ting; Huang, Yueh-Min

2017-01-01

English learning has become a vital educational strategy in many non-English-speaking countries. Vocabulary is a critical element for language learners. Therefore, developing sufficient vocabulary knowledge enables effective communication. However, learning a foreign language is difficult and stressful. In addition, memorizing English vocabulary…

Countering China’s Dominance in the Rare Earth Element Market System

DTIC Science & Technology

2012-02-02

critical materials such as cadmium , tellurium, and helium, which will be required to maintain energy, economic, and defense material independence in...Defense Applications,‖ Paper presented at the 40th Forum on the Geology of Industrial Minerals, Bloomington, Indiana , May 2, 2004, 1. http

Disrupting Charted Systems: Identifying and Deconstructing Critical Incidents in Teaching

ERIC Educational Resources Information Center

Shadiow, Linda K.

2010-01-01

Professional stories that live within multiple retellings throughout one's career can, when the teller analyzes them, be useful in unearthing influential pedagogical assumptions. The author retells a classroom story, examines unacknowledged fears rooted within the story's elements, and uses a five-point framework for analyzing related assumptions…

Earth Observing System (EOS)/Advanced Microwave Sounding Unit-A (AMSU-A) Stress Analysis Report, A1 Module. Addendum 1

NASA Technical Reports Server (NTRS)

Ely, W.

1996-01-01

This addendum reports the structural margins of safety and natural frequency predictions for the design following the EOS AMSU-A1 Mechanical/Structural Subsystem Critical Design Review (CDR), based on a new and more refined finite element model.

Selenium cycling across soil-plant atmosphere interfaces: a critical review

USDA-ARS?s Scientific Manuscript database

Selenium (Se) is an essential element for humans and animals, which occurs ubiquitously in the environment. It is present in trace amounts in both organic and inorganic forms in marine and freshwater systems, soils, biomass, and in the atmosphere. Low Se levels in certain terrestrial environments ha...

Base Camp Life Cycle Management: Focusing on the Critical Elements

DTIC Science & Technology

2011-12-01

needs of the occupants, although “building” this infrastructure often meant cobbling together prefabricated buildings or tents as much as it meant...as System Boundaries.” Journal of Industrial Ecology 10, no. 1 (2006): 61-77. Rebitzer, G. and Hunkeler, D. Life Cycle Costing in LCM: Ambitions

Education Facilities Sector-Specific Plan: An Annex to the Government Facilities Sector-Specific Plan

ERIC Educational Resources Information Center

US Department of Homeland Security, 2010

2010-01-01

Critical infrastructure and key resources (CIKR) provide the essential services that support basic elements of American society. Compromise of these CIKR could disrupt key government and industry activities, facilities, and systems, producing cascading effects throughout the Nation's economy and society and profoundly affecting the national…

SUBTLE: Situation Understanding Bot through Language and Environment

DTIC Science & Technology

2016-01-06

a 4 day “hackathon” by Stuart Young’s small robots group which successfully ported the SUBTLE MURI NLP robot interface to the Packbot platform they...null element restoration, a step typically ig- nored in NLP systems, allows for correct parsing of im- peratives and questions, critical structures

Food Safety, Farm to Fork.

ERIC Educational Resources Information Center

Jones, Rebecca

1998-01-01

In response to growing threat of food-borne illness, the federal government launched the Food Safety Initiative. A key element is the Hazard Analysis Critical Control Points system (HACCP), designed to make everyone in the food-delivery chain responsible for ensuring a safe food supply. The Food and Drug Administration also announced a beef…

Teachers as Learners: Implications of Adult Education for Professional Development

ERIC Educational Resources Information Center

Beavers, Amy

2009-01-01

Effective communication with teachers is a critical element of any successful professional development. Teachers are the foundational component of any educational system. It is vital that adequate attention is focused on appropriate and effective training of these teachers. Ideally, professional development offers a means of collaborative support…

Improving care by understanding the way we work: human factors and behavioural science in the context of intensive care

PubMed Central

Sevdalis, Nick; Brett, Stephen J

2009-01-01

Effectiveness and efficiency of care of the critically ill patient are subject to a number of systemic influences, including skills of individual physicians/nurses (technical and non-technical), team-working in the intensive care unit (ICU), and the ICU environment. We first discuss the paper of Fackler and colleagues as a contribution to the systems approach to clinical performance in the context of intensive care. We then highlight features of care delivery that are unique to intensive care and discuss the need for better understanding of human and non-human elements of the system of care of the critically ill patient as a driver for improvement of care delivery. PMID:19439048

Method and apparatus for in-cell vacuuming of radiologically contaminated materials

DOEpatents

Spadaro, Peter R.; Smith, Jay E.; Speer, Elmer L.; Cecconi, Arnold L.

1987-01-01

A vacuum air flow operated cyclone separator arrangement for collecting, handling and packaging loose contaminated material in accordance with acceptable radiological and criticality control requirements. The vacuum air flow system includes a specially designed fail-safe prefilter installed upstream of the vacuum air flow power supply. The fail-safe prefilter provides in-cell vacuum system flow visualization and automatically reduces or shuts off the vacuum air flow in the event of an upstream prefilter failure. The system is effective for collecting and handling highly contaminated radiological waste in the form of dust, dirt, fuel element fines, metal chips and similar loose material in accordance with radiological and criticality control requirements for disposal by means of shipment and burial.

Fabrication and Testing of CERMET Fuel Materials for Nuclear Thermal Propulsion

NASA Technical Reports Server (NTRS)

Hickman, Robert; Broadway, Jeramie; Mireles, Omar

2012-01-01

A first generation Nuclear Cryogenic Propulsion Stage (NCPS) based on Nuclear Thermal Propulsion (NTP) is currently being developed for Advanced Space Exploration Systems. The overall goal of the project is to address critical NTP technology challenges and programmatic issues to establish confidence in the affordability and viability of NTP systems. The current technology roadmap for NTP identifies the development of a robust fuel form as a critical near term need. The lack of a qualified nuclear fuel is a significant technical risk that will require a considerable fraction of program resources to mitigate. Due to these risks and the cost for qualification, the development and selection of a primary fuel must begin prior to Authority to Proceed (ATP) for a specific mission. The fuel development is a progressive approach to incrementally reduce risk, converge the fuel materials, and mature the design and fabrication process of the fuel element. A key objective of the current project is to advance the maturity of CERMET fuels. The work includes fuel processing development and characterization, fuel specimen hot hydrogen screening, and prototypic fuel element testing. Early fuel materials development is critical to help validate requirements and fuel performance. The purpose of this paper is to provide an overview and status of the work at Marshall Space Flight Center (MSFC).

System Analysis and Performance Benefits of an Optimized Rotorcraft Propulsion System

NASA Technical Reports Server (NTRS)

Bruckner, Robert J.

2007-01-01

The propulsion system of rotorcraft vehicles is the most critical system to the vehicle in terms of safety and performance. The propulsion system must provide both vertical lift and forward flight propulsion during the entire mission. Whereas propulsion is a critical element for all flight vehicles, it is particularly critical for rotorcraft due to their limited safe, un-powered landing capability. This unparalleled reliability requirement has led rotorcraft power plants down a certain evolutionary path in which the system looks and performs quite similarly to those of the 1960 s. By and large the advancements in rotorcraft propulsion have come in terms of safety and reliability and not in terms of performance. The concept of the optimized propulsion system is a means by which both reliability and performance can be improved for rotorcraft vehicles. The optimized rotorcraft propulsion system which couples an oil-free turboshaft engine to a highly loaded gearbox that provides axial load support for the power turbine can be designed with current laboratory proven technology. Such a system can provide up to 60% weight reduction of the propulsion system of rotorcraft vehicles. Several technical challenges are apparent at the conceptual design level and should be addressed with current research.

Investigating Planetesimal Evolution by Experiments with Fe-Ni Metallic Melts: Light Element Composition Effects on Trace Element Partitioning Behavior

NASA Astrophysics Data System (ADS)

Chabot, N. L.

2017-12-01

As planetesimals were heated up in the early Solar System, the formation of Fe-Ni metallic melts was a common occurrence. During planetesimal differentiation, the denser Fe-Ni metallic melts separated from the less dense silicate components, though some meteorites suggest that their parent bodies only experienced partial differentiation. If the Fe-Ni metallic melts did form a central metallic core, the core eventually crystallized to a solid, some of which we sample as iron meteorites. In all of these planetesimal evolution processes, the composition of the Fe-Ni metallic melt influenced the process and the resulting trace element chemical signatures. In particular, the metallic melt's "light element" composition, those elements present in the metallic melt in a significant concentration but with lower atomic masses than Fe, can strongly affect trace element partitioning. Experimental studies have provided critical data to determine the effects of light elements in Fe-Ni metallic melts on trace element partitioning behavior. Here I focus on combining numerous experimental results to identify trace elements that provide unique insight into constraining the light element composition of early Solar System Fe-Ni metallic melts. Experimental studies have been conducted at 1 atm in a variety of Fe-Ni systems to investigate the effects of light elements on trace element partitioning behavior. A frequent experimental examination of the effects of light elements in metallic systems involves producing run products with coexisting solid metal and liquid metal phases. Such solid-metal-liquid-metal experiments have been conducted in the Fe-Ni binary system as well as Fe-Ni systems with S, P, and C. Experiments with O-bearing or Si-bearing Fe-Ni metallic melts do not lend themselves to experiments with coexisting solid metal and liquid metal phases, due to the phase diagrams of these elements, but experiments with two immiscible Fe-Ni metallic melts have provided insight into the qualitative effects of O and Si relative to the well-determined effects of S. Together, these experimental studies provide a robust dataset to identify key elements that are predicted to produce distinct chemical signatures as a function of different Fe-Ni metallic melt compositions during planetesimal evolution processes.

ISEScan: automated identification of insertion sequence elements in prokaryotic genomes.

PubMed

Xie, Zhiqun; Tang, Haixu

2017-11-01

The insertion sequence (IS) elements are the smallest but most abundant autonomous transposable elements in prokaryotic genomes, which play a key role in prokaryotic genome organization and evolution. With the fast growing genomic data, it is becoming increasingly critical for biology researchers to be able to accurately and automatically annotate ISs in prokaryotic genome sequences. The available automatic IS annotation systems are either providing only incomplete IS annotation or relying on the availability of existing genome annotations. Here, we present a new IS elements annotation pipeline to address these issues. ISEScan is a highly sensitive software pipeline based on profile hidden Markov models constructed from manually curated IS elements. ISEScan performs better than existing IS annotation systems when tested on prokaryotic genomes with curated annotations of IS elements. Applying it to 2784 prokaryotic genomes, we report the global distribution of IS families across taxonomic clades in Archaea and Bacteria. ISEScan is implemented in Python and released as an open source software at https://github.com/xiezhq/ISEScan. hatang@indiana.edu. Supplementary data are available at Bioinformatics online. © The Author 2017. Published by Oxford University Press. All rights reserved. For Permissions, please e-mail: journals.permissions@oup.com

ENDF/B-VII.1 Neutron Cross Section Data Testing with Critical Assembly Benchmarks and Reactor Experiments

NASA Astrophysics Data System (ADS)

Kahler, A. C.; MacFarlane, R. E.; Mosteller, R. D.; Kiedrowski, B. C.; Frankle, S. C.; Chadwick, M. B.; McKnight, R. D.; Lell, R. M.; Palmiotti, G.; Hiruta, H.; Herman, M.; Arcilla, R.; Mughabghab, S. F.; Sublet, J. C.; Trkov, A.; Trumbull, T. H.; Dunn, M.

2011-12-01

The ENDF/B-VII.1 library is the latest revision to the United States' Evaluated Nuclear Data File (ENDF). The ENDF library is currently in its seventh generation, with ENDF/B-VII.0 being released in 2006. This revision expands upon that library, including the addition of new evaluated files (was 393 neutron files previously, now 423 including replacement of elemental vanadium and zinc evaluations with isotopic evaluations) and extension or updating of many existing neutron data files. Complete details are provided in the companion paper [M. B. Chadwick et al., "ENDF/B-VII.1 Nuclear Data for Science and Technology: Cross Sections, Covariances, Fission Product Yields and Decay Data," Nuclear Data Sheets, 112, 2887 (2011)]. This paper focuses on how accurately application libraries may be expected to perform in criticality calculations with these data. Continuous energy cross section libraries, suitable for use with the MCNP Monte Carlo transport code, have been generated and applied to a suite of nearly one thousand critical benchmark assemblies defined in the International Criticality Safety Benchmark Evaluation Project's International Handbook of Evaluated Criticality Safety Benchmark Experiments. This suite covers uranium and plutonium fuel systems in a variety of forms such as metallic, oxide or solution, and under a variety of spectral conditions, including unmoderated (i.e., bare), metal reflected and water or other light element reflected. Assembly eigenvalues that were accurately predicted with ENDF/B-VII.0 cross sections such as unmoderated and uranium reflected 235U and 239Pu assemblies, HEU solution systems and LEU oxide lattice systems that mimic commercial PWR configurations continue to be accurately calculated with ENDF/B-VII.1 cross sections, and deficiencies in predicted eigenvalues for assemblies containing selected materials, including titanium, manganese, cadmium and tungsten are greatly reduced. Improvements are also confirmed for selected actinide reaction rates such as 236U, 238,242Pu and 241,243Am capture in fast systems. Other deficiencies, such as the overprediction of Pu solution system critical eigenvalues and a decreasing trend in calculated eigenvalue for 233U fueled systems as a function of Above-Thermal Fission Fraction remain. The comprehensive nature of this critical benchmark suite and the generally accurate calculated eigenvalues obtained with ENDF/B-VII.1 neutron cross sections support the conclusion that this is the most accurate general purpose ENDF/B cross section library yet released to the technical community.

Flood vulnerability evaluation in complex urban areas

NASA Astrophysics Data System (ADS)

Giosa, L.; Pascale, S.; Sdao, F.; Sole, A.; Cantisani, A.

2009-04-01

This paper deals the conception, the development and the subsequent validation of an integrated numerical model for the assessment of systemic vulnerability in complex and urbanized areas, subject to flood risk. The proposed methodology is based on the application of the concept of "systemic vulnerability", the model is a mathematician-decisional model action to estimate the vulnerability of complex a territorial system during a flood event. The model uses a group of "pressure pointers" in order to define, qualitatively and quantitatively, the influence exercised on the territorial system from factors like as those physicists, social, economic, etc.. The model evaluates the exposure to the flood risk of the elements that belong to a system. The proposed model, which is based on the studies of Tamura et al., 2000; Minciardi et al., 2004; Pascale et al., 2008; considers the vulnerability not as a characteristic of a particular element at risk, but as a peculiarity of a complex territorial system, in which the different elements are reciprocally linked in a functional way. The proposed model points out the elements with the major functional lost and that make the whole system critical. This characteristic makes the proposed model able to support a correct territorial planning and a suitable management of the emergency following natural disasters such as floods. The proposed approach was tested on the study area in the city of Potenza, southern Italy.

The critical role of psychosomatics in promoting a new perspective upon health and disease.

PubMed

Dragoş, Dorin; Tănăsescu, Maria Daniela

2009-01-01

In an evolutionary model, health and disease are regarded as successful and respectively failed adaptation to the demands of the environment. The social factors are critical for a successful adaptation, while emotions are means of both signaling the organism's state and of adapting the physiological responses to environmental challenges. Hence the importance of a biopsychosocial model of health and disease. Psychoemotional distress generates and/or amplifies somatic symptoms. Somatization may be viewed as an altered cognitive process, inclining the individual to an augmented perception of bodily sensations and to an increased degree of complexity in reporting negative experiences (hence the greater cognitive effort allocated thereto). Somatosensory amplification and alexithymia are key elements in this process. The brain's right hemisphere is more involved in the generation of emotionally conditioned somatization symptoms. Somatic symptoms have various psychological and social functions and are strongly influenced by the particular belief system of the individual. Inappropriately perceiving the environment as an aggressor and excessively responding to it (by activating the cytokine system in correlation with the arousal of the psychic, nervous, and endocrine systems) may be a key element in the altered cognition conducive to ill health.

Alternative Approach to Vehicle Element Processing

NASA Technical Reports Server (NTRS)

Huether, Jacob E.; Otto, Albert E.

1995-01-01

The National Space Transportation Policy (NSTP), describes the challenge facing today's aerospace industry. 'Assuring reliable and affordable access to space through U.S. space transportation capabilities is a fundamental goal of the U.S. space program'. Experience from the Space Shuttle Program (SSP) tells us that launch and mission operations are responsible for approximately 45 % of the cost of each shuttle mission. Reducing these costs is critical to NSTP goals in the next generation launch vehicle. Based on this, an innovative alternative approach to vehicle element processing was developed with an emphasis on reduced launch costs. State-of-the-art upgrades to the launch processing system (LPS) will enhance vehicle ground operations. To carry this one step further, these upgrade could be implemented at various vehicle element manufacturing sites to ensure system compatibility between the manufacturing facility and the launch site. Design center vehicle stand alone testing will ensure system integrity resulting in minimized checkout and testing at the launch site. This paper will addresses vehicle test requirements, timelines and ground checkout procedures which enable concept implementation.

A New Real - Time Fault Detection Methodology for Systems Under Test. Phase 1

NASA Technical Reports Server (NTRS)

Johnson, Roger W.; Jayaram, Sanjay; Hull, Richard A.

1998-01-01

The purpose of this research is focussed on the identification/demonstration of critical technology innovations that will be applied to various applications viz. Detection of automated machine Health Monitoring (BM, real-time data analysis and control of Systems Under Test (SUT). This new innovation using a High Fidelity Dynamic Model-based Simulation (BFDMS) approach will be used to implement a real-time monitoring, Test and Evaluation (T&E) methodology including the transient behavior of the system under test. The unique element of this process control technique is the use of high fidelity, computer generated dynamic models to replicate the behavior of actual Systems Under Test (SUT). It will provide a dynamic simulation capability that becomes the reference truth model, from which comparisons are made with the actual raw/conditioned data from the test elements.

A model for assessing the systemic vulnerability in landslide prone areas

NASA Astrophysics Data System (ADS)

Pascale, S.; Sdao, F.; Sole, A.

2010-07-01

The objectives of spatial planning should include the definition and assessment of possible mitigation strategies regarding the effects of natural hazards on the surrounding territory. Unfortunately, however, there is often a lack of adequate tools to provide necessary support to the local bodies responsible for land management. This paper deals with the conception, the development and the validation of an integrated numerical model for assessing systemic vulnerability in complex and urbanized landslide-prone areas. The proposed model considers this vulnerability not as a characteristic of a particular element at risk, but as a peculiarity of a complex territorial system, in which the elements are reciprocally linked in a functional way. It is an index of the tendency of a given territorial element to suffer damage (usually of a functional kind) due to its interconnections with other elements of the same territorial system. The innovative nature of this work also lies in the formalization of a procedure based on a network of influences for an adequate assessment of such "systemic" vulnerability. This approach can be used to obtain information which is useful, in any given situation of a territory hit by a landslide event, for the identification of the element which has suffered the most functional damage, ie the most "critical" element and the element which has the greatest repercussions on other elements of the system and thus a "decisive" role in the management of the emergency. This model was developed within a GIS system through the following phases: 1. the topological characterization of the territorial system studied and the assessment of the scenarios in terms of spatial landslide hazard. A statistical method, based on neural networks was proposed for the assessment of landslide hazard; 2. the analysis of the direct consequences of a scenario event on the system; 3. the definition of the assessment model of systemic vulnerability in landslide-prone areas. To highlight the potentialities of the proposed approach we have described a specific case study of landslide hazard in the local council area of Potenza.

A parallel finite element procedure for contact-impact problems using edge-based smooth triangular element and GPU

NASA Astrophysics Data System (ADS)

Cai, Yong; Cui, Xiangyang; Li, Guangyao; Liu, Wenyang

2018-04-01

The edge-smooth finite element method (ES-FEM) can improve the computational accuracy of triangular shell elements and the mesh partition efficiency of complex models. In this paper, an approach is developed to perform explicit finite element simulations of contact-impact problems with a graphical processing unit (GPU) using a special edge-smooth triangular shell element based on ES-FEM. Of critical importance for this problem is achieving finer-grained parallelism to enable efficient data loading and to minimize communication between the device and host. Four kinds of parallel strategies are then developed to efficiently solve these ES-FEM based shell element formulas, and various optimization methods are adopted to ensure aligned memory access. Special focus is dedicated to developing an approach for the parallel construction of edge systems. A parallel hierarchy-territory contact-searching algorithm (HITA) and a parallel penalty function calculation method are embedded in this parallel explicit algorithm. Finally, the program flow is well designed, and a GPU-based simulation system is developed, using Nvidia's CUDA. Several numerical examples are presented to illustrate the high quality of the results obtained with the proposed methods. In addition, the GPU-based parallel computation is shown to significantly reduce the computing time.

Defense AT&L. Volume 40, Number 5, September-October 2011

DTIC Science & Technology

2011-10-01

training, the path to better buying power, and the keys to career success . 9 Systems Engineering: the Affordability Secret Weapon Mike Holbert A...Enabler A Critical Fourth Element of Acquisition Success Across the System Life Cycle Bill Kobren Program managers and their colleagues must adopt a...acquisition outcomes. The real challenge and ultimate measure of our success is the ability to incorporate these initiatives into the culture of our

RF Spectrum Sensing Based on an Overdamped Nonlinear Oscillator Ring for Cognitive Radios

PubMed Central

Tang, Zhi-Ling; Li, Si-Min; Yu, Li-Juan

2016-01-01

Existing spectrum-sensing techniques for cognitive radios require an analog-to-digital converter (ADC) to work at high dynamic range and a high sampling rate, resulting in high cost. Therefore, in this paper, a spectrum-sensing method based on a unidirectionally coupled, overdamped nonlinear oscillator ring is proposed. First, the numerical model of such a system is established based on the circuit of the nonlinear oscillator. Through numerical analysis of the model, the critical condition of the system’s starting oscillation is determined, and the simulation results of the system’s response to Gaussian white noise and periodic signal are presented. The results show that once the radio signal is input into the system, it starts oscillating when in the critical region, and the oscillating frequency of each element is fo/N, where fo is the frequency of the radio signal and N is the number of elements in the ring. The oscillation indicates that the spectrum resources at fo are occupied. At the same time, the sampling rate required for an ADC is reduced to the original value, 1/N. A prototypical circuit to verify the functionality of the system is designed, and the sensing bandwidth of the system is measured. PMID:27294928

Space Shuttle Software Development and Certification

NASA Technical Reports Server (NTRS)

Orr, James K.; Henderson, Johnnie A

2000-01-01

Man-rated software, "software which is in control of systems and environments upon which human life is critically dependent," must be highly reliable. The Space Shuttle Primary Avionics Software System is an excellent example of such a software system. Lessons learn from more than 20 years of effort have identified basic elements that must be present to achieve this high degree of reliability. The elements include rigorous application of appropriate software development processes, use of trusted tools to support those processes, quantitative process management, and defect elimination and prevention. This presentation highlights methods used within the Space Shuttle project and raises questions that must be addressed to provide similar success in a cost effective manner on future long-term projects where key application development tools are COTS rather than internally developed custom application development tools

Automatic Clustering of Rolling Element Bearings Defects with Artificial Neural Network

NASA Astrophysics Data System (ADS)

Antonini, M.; Faglia, R.; Pedersoli, M.; Tiboni, M.

2006-06-01

The paper presents the optimization of a methodology for automatic clustering based on Artificial Neural Networks to detect the presence of defects in rolling bearings. The research activity was developed in co-operation with an Italian company which is expert in the production of water pumps for automotive use (Industrie Saleri Italo). The final goal of the work is to develop a system for the automatic control of the pumps, at the end of the production line. In this viewpoint, we are gradually considering the main elements of the water pump, which can cause malfunctioning. The first elements we have considered are the rolling bearing, a very critic component for the system. The experimental activity is based on the vibration measuring of rolling bearings opportunely damaged; vibration signals are in the second phase elaborated; the third and last phase is an automatic clustering. Different signal elaboration techniques are compared to optimize the methodology.

Dependability: a challenge for electrical medical implants.

PubMed

Cathébras, Guy; Le Floch, Fanny; Bernard, Serge; Soulier, Fabien

2010-01-01

Functional Electrical Stimulation (FES) is an attractive solution to restore some lost or failing physiological functions. Obviously, the FES system may be hazardous for patient and the reliability and dependability of the system must be maximal. Unfortunately, the present context, where the associated systems are more and more complex and their development needs very cross-disciplinary experts, is not favorable to safety. Moreover, the direct adaptation of the existing dependability techniques from domains such as space or automotive is not suitable. Firstly, this paper proposes a strategy for risk management at system level for FES medical implant. The idea is to give a uniform framework where all possible hazards are highlighted and associated consequences are minimized. Then, the paper focuses on critical parts of the FES system: analog micro-circuit which generates the electrical signal to electrode. As this micro-circuit is the closest to the human tissue, any failure might involve very critical consequences for the patient. We propose a concurrent top-down and bottom-up approach where the critical elements are highlighted and an extended risk analysis is performed.

Three success factors for continual improvement in healthcare: an analysis of the reports of improvement team members.

PubMed

Brandrud, Aleidis Skard; Schreiner, Ada; Hjortdahl, Per; Helljesen, Gro Sævil; Nyen, Bjørnar; Nelson, Eugene C

2011-03-01

The objectives of the Breakthrough Series Collaborative are to close the gap between what we know and what we do, and to contribute to continuous quality improvement (CQI) of healthcare through collaborative learning. The improvement efforts are guided by a systematic approach, combining professional and improvement knowledge. To explore what the improvement teams have learnt from participating in the collaborative and from dealing with promoting and inhibiting factors encountered. Qualitative interviews with 19 team members were conducted in four focus groups, using the Critical Incident Technique. A critical incident is one that makes significant contributions, either positively or negatively, to an activity. The elements of a culture of improvement are revealed by the critical incidents, and reflect the eight domains of knowledge, as a product of collaborative learning. The improvement knowledge and skills of individuals are important elements, but not enough to achieve sustainable changes. 90% of the material reflects the need for a system of CQI to solve the problems that organisations experience in trying to make lasting improvements. A pattern of three success factors for CQI emerges: (1) continuous and reliable information, including measurement, about best and current practice; (2) engagement of everybody in all phases of the improvement work: the patient and family, the leadership, the professional environment and the staff; and (3) an infrastructure based on improvement knowledge, with multidisciplinary teams, available coaching, learning systems and sustainability systems.

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.

Validation of Hansen-Roach library for highly enriched uranium metal systems

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

Wenz, T.R.; Busch, R.D.

The Hansen-Roach 16-group cross-section library has been validated for use in pure uranium metal systems by modeling the Godiva critical assembly using the neutronics transport theory code ONEDANT to perform effective multiplication factor (k{sub eff}) calculations. The cross-section library used contains data for 118 isotopes (34 unique elements), including the revised cross sections for {sup 235}U and {sup 238}U. The Godiva critical assembly is a 17.4-cm sphere composed of 93.7 wt% {sup 235}U, 1.0 wt% {sup 234}U, and 5.3 wt% {sup 238}U with an effective homogeneous density of 18.7 g/cm{sup 3}.

Facilitating Reforms in STEM Undergraduate Education: An Administrative Perspective

ERIC Educational Resources Information Center

Litzinger, Thomas A.; Koubek, Richard J.; Wormley, David N.

2009-01-01

One of the most important elements in achieving significant curricular and pedagogical innovation is creating a climate that promotes and acknowledges the contributions of those who engage in these efforts. It is critical that this climate be systemic, existing at the department, college, and university levels. In the past few years, the view that…

75 FR 29967 - National Organic Program Request for an Extension of a Currently Approved Information Collection

Federal Register 2010, 2011, 2012, 2013, 2014

2010-05-28

... the organic certification system. They create a paper trail that is a critical element in carrying out..., organic inspectors, certified organic producers and handlers, those seeking accreditation or certification.... USDA also permits States to establish their own organic certification programs after the programs are...

Challenges of Engineering Higher Education in a Transitional Economy: A Russian Experience

ERIC Educational Resources Information Center

Matveev, Alexei; Matveev, Olga; Zhukov, Vassily

2005-01-01

Education and training serve as critical elements of advancement of a nation's economy in transition. The restructuring of the power engineering industry in Russia has called for a fast implementation of new management system in electric power engineering and radical training of professional managers at different levels in organizations.…

A World-Class University in China? The Case of Tsinghua

ERIC Educational Resources Information Center

Yang, Rui; Welch, Anthony

2012-01-01

Higher education, an integral part of China's nation-building project, is a critical element in China's strategic policy initiative of building national strength through science and education. One way to achieve this goal is to develop a higher education system of international stature. Perhaps more than any other country, through national…

Administrative Procedures for the Fort Lincoln Schools. Fort Lincoln New Town Education System.

ERIC Educational Resources Information Center

General Learning Corp., Washington, DC.

This is an operating manual for administration of the educational program to be used by the staff of the Fort Lincoln First Facility. It details specifications regarding information flow, storage, output, time cycles, staffing provisions, authority and responsibility provisions. An effort has been made to include those elements critical to…

Data: Meaningful Analysis Can Rescue Schools from Drowning in Data

ERIC Educational Resources Information Center

Reeves, Douglas B.; Flach, Tony

2011-01-01

Learning Forward's Standards for Professional Learning have the potential to influence educational policy and practice in profound ways for the systems that are courageous enough to take them seriously, and the Data standard is a critical element systemwide. Schools are overwhelmed with data warehouses, colorful charts and graphs, and endless…

A summary of recent NASA/Army contributions to rotorcraft vibrations and structural dynamics technology

NASA Technical Reports Server (NTRS)

Kvaternik, Raymond G.; Bartlett, Felton D., Jr.; Cline, John H.

1988-01-01

The requirement for low vibrations has achieved the status of a critical design consideration in modern helicopters. There is now a recognized need to account for vibrations during both the analytical and experimental phases of design. Research activities in this area were both broad and varied and notable advances were made in recent years in the critical elements of the technology base needed to achieve the goal of a jet smooth ride. The purpose is to present an overview of accomplishments and current activities of govern and government-sponsored research in the area of rotorcraft vibrations and structural dynamics, focusing on NASA and Army contributions over the last decade or so. Specific topics addressed include: airframe finite-element modeling for static and dynamic analyses, analysis of coupled rotor-airframe vibrations, optimization of airframes subject to vibration constraints, active and passive control of vibrations in both the rotating and fixed systems, and integration of testing and analysis in such guises as modal analysis, system identification, structural modification, and vibratory loads measurement.

NASA's Chemical Transfer Propulsion Program for Pathfinder

NASA Technical Reports Server (NTRS)

Hannum, Ned P.; Berkopec, Frank D.; Zurawski, Robert L.

1989-01-01

Pathfinder is a research and technology project, with specific deliverables, initiated by the National Aeronautics and Space Administration (NASA) which will strengthen the technology base of the United States civil space program in preparation for future space exploration missions. Pathfinder begins in Fiscal Year 1989, and is to advance a collection of critical technologies for these missions and ensure technology readiness for future national decisions regarding exploration of the solar system. The four major thrusts of Pathfinder are: surface exploration, in-space operations, humans-in-space, and space transfer. The space transfer thrust will provide the critical technologies needed for transportation to, and return from, the Moon, Mars, and other planets in the solar system, as well as for reliable and cost-effective Earth-orbit operations. A key element of this thrust is the Chemical Transfer Propulsion program which will provide the propulsion technology for high performance, liquid oxygen/liquid hydrogen expander cycle engines which may be operated and maintained in space. Described here are the program overview including the goals and objectives, management, technical plan, and technology transfer for the Chemical Transfer Propulsion element of Pathfinder.

Evolution of the Campanian Ignimbrite Magmatic System II: Trace Element and Th Isotopic Evidence for Open-System Processes

NASA Astrophysics Data System (ADS)

Bohrson, W. A.; Spera, F. J.; Fowler, S.; Belkin, H.; de Vivo, B.

2005-12-01

The Campanian Ignimbrite, a large volume (~200 km3 DRE) trachytic to phonolitic ignimbrite was deposited at ~39.3 ka and represents the largest of a number of highly explosive volcanic events in the region near Naples, Italy. Thermodynamic modeling of the major element evolution using the MELTS algorithm (see companion contribution by Fowler et al.) provides detailed information about the identity of and changes in proportions of solids along the liquid line of descent during isobaric fractional crystallization. We have derived trace element mass balance equations that explicitly accommodate changing mineral-melt bulk distribution coefficients during crystallization and also simultaneously satisfy energy and major element mass conservation. Although major element patterns are reasonably modeled assuming closed system fractional crystallization, modeling of trace elements that represent a range of behaviors (e.g. Zr, Nb, Th, U, Rb, Sm, Sr) yields trends for closed system fractionation that are distinct from those observed. These results suggest open-system processes were also important in the evolution of the Campanian magmatic system. Th isotope data yield an apparent isochron that is ~20 kyr younger than the age of the deposit, and age-corrected Th isotope data indicate that the magma body was an open-system at the time of eruption. Because open-system processes can profoundly change isotopic characteristics of a magma body, these results illustrate that it is critical to understand the contribution that open-system processes make to silicic magma bodies prior to assigning relevance to age or timescale information derived from isotope systematics. Fluid-magma interaction has been proposed as a mechanism to change isotopic and elemental characteristics of magma bodies, but an evaluation of the mass and thermal constraints on such a process suggest large-scale fluid-melt interaction at liquidus temperatures is unlikely. In the case of the magma body associated with the Campanian Ignimbrite, the most likely source of open-system signatures is assimilation of partial melts of compositionally heterogeneous basement composed of older cumulates and intrusive equivalents of volcanic activity within the Campanian region. Additional trace element modeling, explicitly evaluating the mass and energy balance effects that fluid, solids, and melt have on trace element evolution, will further elucidate the contributions of open vs. closed system processes within the Campanian magma body.

Engagement and Education

PubMed Central

Tosh, Pritish K.; Hick, John L.; Hanfling, Dan; Geiling, James; Reed, Mary Jane; Uyeki, Timothy M.; Shah, Umair A.; Fagbuyi, Daniel B.; Skippen, Peter; Dichter, Jeffrey R.; Kissoon, Niranjan; Christian, Michael D.; Upperman, Jeffrey S.; Christian, Michael D.; Devereaux, Asha V.; Dichter, Jeffrey R.; Kissoon, Niranjan; Rubinson, Lewis; Amundson, Dennis; Anderson, Michael R.; Balk, Robert; Barfield, Wanda D.; Bartz, Martha; Benditt, Josh; Beninati, William; Berkowitz, Kenneth A.; Daugherty Biddison, Lee; Braner, Dana; Branson, Richard D; Burkle, Frederick M.; Cairns, Bruce A.; Carr, Brendan G.; Courtney, Brooke; DeDecker, Lisa D.; De Jong, Marla J.; Dominguez-Cherit, Guillermo; Dries, David; Einav, Sharon; Erstad, Brian L.; Etienne, Mill; Fagbuyi, Daniel B.; Fang, Ray; Feldman, Henry; Garzon, Hernando; Geiling, James; Gomersall, Charles D.; Grissom, Colin K.; Hanfling, Dan; Hick, John L.; Hodge, James G.; Hupert, Nathaniel; Ingbar, David; Kanter, Robert K.; King, Mary A.; Kuhnley, Robert N.; Lawler, James; Leung, Sharon; Levy, Deborah A.; Lim, Matthew L.; Livinski, Alicia; Luyckx, Valerie; Marcozzi, David; Medina, Justine; Miramontes, David A.; Mutter, Ryan; Niven, Alexander S.; Penn, Matthew S.; Pepe, Paul E.; Powell, Tia; Prezant, David; Reed, Mary Jane; Rich, Preston; Rodriquez, Dario; Roxland, Beth E.; Sarani, Babak; Shah, Umair A.; Skippen, Peter; Sprung, Charles L.; Subbarao, Italo; Talmor, Daniel; Toner, Eric S.; Tosh, Pritish K.; Upperman, Jeffrey S.; Uyeki, Timothy M.; Weireter, Leonard J.; West, T. Eoin; Wilgis, John; Ornelas, Joe; McBride, Deborah; Reid, David; Baez, Amado; Baldisseri, Marie; Blumenstock, James S.; Cooper, Art; Ellender, Tim; Helminiak, Clare; Jimenez, Edgar; Krug, Steve; Lamana, Joe; Masur, Henry; Mathivha, L. Rudo; Osterholm, Michael T.; Reynolds, H. Neal; Sandrock, Christian; Sprecher, Armand; Tillyard, Andrew; White, Douglas; Wise, Robert; Yeskey, Kevin

2014-01-01

BACKGROUND: Engagement and education of ICU clinicians in disaster preparedness is fragmented by time constraints and institutional barriers and frequently occurs during a disaster. We reviewed the existing literature from 2007 to April 2013 and expert opinions about clinician engagement and education for critical care during a pandemic or disaster and offer suggestions for integrating ICU clinicians into planning and response. The suggestions in this article are important for all of those involved in a pandemic or large-scale disaster with multiple critically ill or injured patients, including front-line clinicians, hospital administrators, and public health or government officials. METHODS: A systematic literature review was performed and suggestions formulated according to the American College of Chest Physicians (CHEST) Consensus Statement development methodology. We assessed articles, documents, reports, and gray literature reported since 2007. Following expert-informed sorting and review of the literature, key priority areas and questions were developed. No studies of sufficient quality were identified upon which to make evidence-based recommendations. Therefore, the panel developed expert opinion-based suggestions using a modified Delphi process. RESULTS: Twenty-three suggestions were formulated based on literature-informed consensus opinion. These suggestions are grouped according to the following thematic elements: (1) situational awareness, (2) clinician roles and responsibilities, (3) education, and (4) community engagement. Together, these four elements are considered to form the basis for effective ICU clinician engagement for mass critical care. CONCLUSIONS: The optimal engagement of the ICU clinical team in caring for large numbers of critically ill patients due to a pandemic or disaster will require a departure from the routine independent systems operating in hospitals. An effective response will require robust information systems; coordination among clinicians, hospitals, and governmental organizations; pre-event engagement of relevant stakeholders; and standardized core competencies for the education and training of critical care clinicians. PMID:25144161

Structural dynamic analysis of the Space Shuttle Main Engine

NASA Technical Reports Server (NTRS)

Scott, L. P.; Jamison, G. T.; Mccutcheon, W. A.; Price, J. M.

1981-01-01

This structural dynamic analysis supports development of the SSME by evaluating components subjected to critical dynamic loads, identifying significant parameters, and evaluating solution methods. Engine operating parameters at both rated and full power levels are considered. Detailed structural dynamic analyses of operationally critical and life limited components support the assessment of engine design modifications and environmental changes. Engine system test results are utilized to verify analytic model simulations. The SSME main chamber injector assembly is an assembly of 600 injector elements which are called LOX posts. The overall LOX post analysis procedure is shown.

Considerations for a design and operations knowledge support system for Space Station Freedom

NASA Technical Reports Server (NTRS)

Erickson, Jon D.; Crouse, Kenneth H.; Wechsler, Donald B.; Flaherty, Douglas R.

1989-01-01

Engineering and operations of modern engineered systems depend critically upon detailed design and operations knowledge that is accurate and authoritative. A design and operations knowledge support system (DOKSS) is a modern computer-based information system providing knowledge about the creation, evolution, and growth of an engineered system. The purpose of a DOKSS is to provide convenient and effective access to this multifaceted information. The complexity of Space Station Freedom's (SSF's) systems, elements, interfaces, and organizations makes convenient access to design knowledge especially important, when compared to simpler systems. The life cycle length, being 30 or more years, adds a new dimension to space operations, maintenance, and evolution. Provided here is a review and discussion of design knowledge support systems to be delivered and operated as a critical part of the engineered system. A concept of a DOKSS for Space Station Freedom (SSF) is presented. This is followed by a detailed discussion of a DOKSS for the Lyndon B. Johnson Space Center and Work Package-2 portions of SSF.

Key ecological challenges for closed systems facilities

NASA Astrophysics Data System (ADS)

Nelson, Mark; Dempster, William F.; Allen, John P.

2013-07-01

Closed ecological systems are desirable for a number of purposes. In space life support systems, material closure allows precious life-supporting resources to be kept inside and recycled. Closure in small biospheric systems facilitates detailed measurement of global ecological processes and biogeochemical cycles. Closed testbeds facilitate research topics which require isolation from the outside (e.g. genetically modified organisms; radioisotopes) so their ecological interactions and fluxes can be studied separate from interactions with the outside environment. But to achieve and maintain closure entails solving complex ecological challenges. These challenges include being able to handle faster cycling rates and accentuated daily and seasonal fluxes of critical life elements such as carbon dioxide, oxygen, water, macro- and mico-nutrients. The problems of achieving sustainability in closed systems for life support include how to handle atmospheric dynamics including trace gases, producing a complete human diet, recycling nutrients and maintaining soil fertility, the maintenance of healthy air and water and preventing the loss of critical elements from active circulation. In biospheric facilities, the challenge is also to produce analogues to natural biomes and ecosystems, studying processes of self-organization and adaptation in systems that allow specification or determination of state variables and cycles which may be followed through all interactions from atmosphere to soils. Other challenges include the dynamics and genetics of small populations, the psychological challenges for small isolated human groups and backup technologies and strategic options which may be necessary to ensure long-term operation of closed ecological systems.

Biological and Bioelectrochemical Recovery of Critical and Scarce Metals.

PubMed

Nancharaiah, Y V; Mohan, S Venkata; Lens, P N L

2016-02-01

Metal-bearing solid and liquid wastes are increasingly considered as secondary sources of critical and scarce metals. Undoubtedly, microorganisms are a cost-effective resource for extracting and concentrating diffuse elements from secondary sources. Microbial biotechnology for extracting base metals from ores and treatment of metal-laden wastewaters has already been applied at full scale. By contrast, microbe-metal interactions in the recovery of scarce metals and a few critical metals have received attention, whereas the recovery of many others has been barely explored. Therefore, this article explores and details the potential application of microbial biotechnologies in the recovery of critical and scarce metals. In the past decade bioelectrochemical systems have emerged as a new technology platform for metal recovery coupled to the removal of organic matter. Copyright © 2015 Elsevier Ltd. All rights reserved.

A Critical Analysis of U.S. Army Accessions through Socioeconomic Consideration between 1970 and 1984.

DTIC Science & Technology

1985-06-01

ADDRESS 10. PROGRAM ELEMENT, PROJECT. TASK AREA & WORK UNIT NUMBERS Naval Postgraduate School Monterey, California 93943 11. CONTROLLING OFFICE NAME AND...determine the sccioeccnomic representativeness of the Army’s enlistees in that iarticular year. In addition, the socioeconomic overviev of Republic cf...accomplished with the use of the Statistical Analysis System (SAS), an integrated computer system for data analysis. 32 TABLE 2 The States in Each District

Advanced On-the-Job Training System: System Specification

DTIC Science & Technology

1990-05-01

3.1.5.2.10 Evaluation Subsystem spotfor the Traking Devopment and Deliery Subsystem ..... 22 3.1.5.2.11 TrIning Development=dDelivery Subsystem sL...e. Alsys Ada compiler f. Ethernet Local Area Network reference manual(s) g. Infotron 992 network reference manual(s) h. Computer Program Source...1989 a. Daily check of mainframe components, including all elements critical to support the terminal network . b. Restoration of mainframe equipment

Size does Matter

NASA Astrophysics Data System (ADS)

Vespignani, Alessandro

From schools of fish and flocks of birds, to digital networks and self-organizing biopolymers, our understanding of spontaneously emergent phenomena, self-organization, and critical behavior is in large part due to complex systems science. The complex systems approach is indeed a very powerful conceptual framework to shed light on the link between the microscopic dynamical evolution of the basic elements of the system and the emergence of oscopic phenomena; often providing evidence for mathematical principles that go beyond the particulars of the individual system, thus hinting to general modeling principles. By killing the myth of the ant queen and shifting the focus on the dynamical interaction across the elements of the systems, complex systems science has ushered our way into the conceptual understanding of many phenomena at the core of major scientific and social challenges such as the emergence of consensus, social opinion dynamics, conflicts and cooperation, contagion phenomena. For many years though, these complex systems approaches to real-world problems were often suffering from being oversimplified and not grounded on actual data...

TOPAZ II Anti-Criticality Device Rapid Prototype

NASA Astrophysics Data System (ADS)

Campbell, Donald R.; Otting, William D.

1994-07-01

The Ballistic Missile Defense Organization (BMDO) has been working on a Nuclear Electric Propulsion Space Test Project (NEPSTP) using an existing Russian Topaz II reactor system to power the NEPSTP satellite. Safety investigations have shown that it will be possible to safely launch the Topaz II system in the United States with some modification to preclude water flooded criticality. A ``fuel-out'' water subcriticality concept was selected by the Los Alamos National Laboratory (LANL) as the baseline concept. A fuel-out anti-criticality device (ACD) conceptual design was developed by Rockwell. The concept functions to hold the fuel from the four centermost thermionic fuel elements (TFEs) outside the reactor during launch and reliably inserts the fuel into the reactor once the operational orbit is achieved. A four-tenths scale ACD rapid prototype model, fabricated from the CATIA solids design model, clearly shows in three dimensions the relative size and spatial relationship of the ACD components.

Demonstration Advanced Avionics System (DAAS)

NASA Technical Reports Server (NTRS)

1982-01-01

The feasibility of developing an integrated avionics system suitable for general aviation was determined. A design of reliable integrated avionics which provides expanded functional capability that significantly enhances the utility and safety of general aviation at a cost commensurate with the general aviation market was developed. The use of a data bus, microprocessors, electronic displays and data entry devices, and improved function capabilities were emphasized. An avionics system capable of evaluating the most critical and promising elements of an integrated system was designed, built and flight tested in a twin engine general aviation aircraft.

Damage and Loss Estimation for Natural Gas Networks: The Case of Istanbul

NASA Astrophysics Data System (ADS)

Çaktı, Eser; Hancılar, Ufuk; Şeşetyan, Karin; Bıyıkoǧlu, Hikmet; Şafak, Erdal

2017-04-01

Natural gas networks are one of the major lifeline systems to support human, urban and industrial activities. The continuity of gas supply is critical for almost all functions of modern life. Under natural phenomena such as earthquakes and landslides the damages to the system elements may lead to explosions and fires compromising human life and damaging physical environment. Furthermore, the disruption in the gas supply puts human activities at risk and also results in economical losses. This study is concerned with the performance of one of the largest natural gas distribution systems in the world. Physical damages to Istanbul's natural gas network are estimated under the most recent probabilistic earthquake hazard models available, as well as under simulated ground motions from physics based models. Several vulnerability functions are used in modelling damages to system elements. A first-order assessment of monetary losses to Istanbul's natural gas distribution network is also attempted.

Integrating emergency services in an urban health system.

PubMed

Radloff, D; Blouin, A S; Larsen, L; Kripp, M E

2000-03-01

When planning for growth and management efficiency across urban health systems, economic and market factors present significant service line challenges and opportunities. This article describes the evolutionary integration of emergency services in St John Health System, a large, religious-sponsored health care system located in Detroit, Michigan. Critical business elements, including the System's vision, mission, and economic context, are defined as the framework for site-specific and System-wide planning. The impact of managed care and market changes prompted St John's clinicians and executives to explore how integrating emergency services could create a competitive market advantage.

Control Activity in Support of NASA Turbine Based Combined Cycle (TBCC) Research

NASA Technical Reports Server (NTRS)

Stueber, Thomas J.; Vrnak, Daniel R.; Le, Dzu K.; Ouzts, Peter J.

2010-01-01

Control research for a Turbine Based Combined Cycle (TBCC) propulsion system is the current focus of the Hypersonic Guidance, Navigation, and Control (GN&C) discipline team. The ongoing work at the NASA Glenn Research Center (GRC) supports the Hypersonic GN&C effort in developing tools to aid the design of control algorithms to manage a TBCC airbreathing propulsion system during a critical operating period. The critical operating period being addressed in this paper is the span when the propulsion system transitions from one cycle to another, referred to as mode transition. One such tool, that is a basic need for control system design activities, is computational models (hereto forth referred to as models) of the propulsion system. The models of interest for designing and testing controllers are Control Development Models (CDMs) and Control Validation Models (CVMs). CDMs and CVMs are needed for each of the following propulsion system elements: inlet, turbine engine, ram/scram dual-mode combustor, and nozzle. This paper presents an overall architecture for a TBCC propulsion system model that includes all of the propulsion system elements. Efforts are under way, focusing on one of the propulsion system elements, to develop CDMs and CVMs for a TBCC propulsion system inlet. The TBCC inlet aerodynamic design being modeled is that of the Combined-Cycle Engine (CCE) Testbed. The CCE Testbed is a large-scale model of an aerodynamic design that was verified in a small-scale screening experiment. The modeling approach includes employing existing state-of-the-art simulation codes, developing new dynamic simulations, and performing system identification experiments on the hardware in the NASA GRC 10 by10-Foot Supersonic Wind Tunnel. The developed CDMs and CVMs will be available for control studies prior to hardware buildup. The system identification experiments on the CCE Testbed will characterize the necessary dynamics to be represented in CDMs for control design. These system identification models will also be the reference models to validate the CDM and CVM models. Validated models will give value to the tools used to develop the models.

Critical elements in Carlin, epithermal, and orogenic gold deposits

USGS Publications Warehouse

Goldfarb, Richard J.; Hofstra, Albert H.; Simmons, Stuart F.

2016-01-01

Carlin, epithermal, and orogenic gold deposits, today mined almost exclusively for their gold content, have similar suites of anomalous trace elements that reflect similar low-salinity ore fluids and thermal conditions of metal transport and deposition. Many of these trace elements are commonly referred to as critical or near-critical elements or metals and have been locally recovered, although typically in small amounts, by historic mining activities. These elements include As, Bi, Hg, In, Sb, Se, Te, Tl, and W. Most of these elements are now solely recovered as by-products from the milling of large-tonnage, base metal-rich ore deposits, such as porphyry and volcanogenic massive sulfide deposits.A combination of dominance of the world market by a single country for a single commodity and a growing demand for many of the critical to near-critical elements could lead to future recovery of such elements from select epithermal, orogenic, or Carlin-type gold deposits. Antimony continues to be recovered from some orogenic gold deposits and tellurium could potentially be a primary commodity from some such deposits. Tellurium and indium in sphalerite-rich ores have been recovered in the past and could be future commodities recovered from epithermal ores. Carlin-type gold deposits in Nevada are enriched in and may be a future source for As, Hg, Sb, and/or Tl. Some of the Devonian carbonaceous host rocks in the Carlin districts are sufficiently enriched in many trace elements, including Hg, Se, and V, such that they also could become resources. Thallium may be locally enriched to economic levels in Carlin-type deposits and it has been produced from Carlin-like deposits elsewhere in the world (e.g., Alsar, southern Macedonia; Lanmuchang, Guizhou province, China). Mercury continues to be recovered from shallow-level epithermal deposits, as well as a by-product of many Carlin-type deposits where refractory ore is roasted to oxidize carbon and pyrite, and mercury is then captured in air pollution control devices.

From bouncing back, to nurturing emergence: reframing the concept of resilience in health systems strengthening.

PubMed

Barasa, Edwine W; Cloete, Keith; Gilson, Lucy

2017-11-01

Recent health system shocks such as the Ebola disease outbreak have focused global health attention on the notion of resilient health systems. In this commentary, we reflect on the current framing of the concept of resilience in health systems discourse and propose a reframing. Specifically, we propose that: (1) in addition to sudden shocks, health systems face the ongoing strain of multiple factors. Health systems need the capacity to continue to deliver services of good quality and respond effectively to wider health challenges. We call this capacity everyday resilience; (2) health system resilience entails more than bouncing back from shock. In complex adaptive systems (CAS), resilience emerges from a combination of absorptive, adaptive and transformative strategies; (3) nurturing the resilience of health systems requires understanding health systems as comprising not only hardware elements (such as finances and infrastructure), but also software elements (such as leadership capacity, power relations, values and appropriate organizational culture). We also reflect on current criticisms of the concept of resilient health systems, such as that it assumes that systems are apolitical, ignoring actor agency, promoting inaction, and requiring that we accept and embrace vulnerability, rather than strive for stronger and more responsive systems. We observe that these criticisms are warranted to the extent that they refer to notions of resilience that are mismatched with the reality of health systems as CAS. We argue that the observed weaknesses of resilience thinking can be addressed by reframing and applying a resilience lens that is better suited to the attributes of health systems as CAS. © The Author 2017. Published by Oxford University Press in association with The London School of Hygiene and Tropical Medicine. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

Comparison of a traditional with a new approach based on Graph Theory to vulnerability assessment to natural hazards: a study case on a socio-economic complex system

NASA Astrophysics Data System (ADS)

Arosio, Marcello; Martina, Mario L. V.

2017-04-01

The emergent behaviour of the contemporary complex, socio-technical and interconnected society makes the collective risk greater than the sum of the parts and this requires a holistic, systematic and integrated approach. Although there have been major improvements in recent years, there are still some limitation in term of a holistic approach that is able to include the emergent value hidden in the connections between exposed elements and the interactions between the different spheres of the multi-hazards, vulnerability, exposure and resilience. To deal with these challenges it is necessary to consider the connections between the exposed elements (e.g. populations, schools, hospital, etc.) and to quantify the relative importance of the elements and their interconnections (e.g. the need of injured people to go to hospital or children to school). In a system (e.g. road, hospital and ecological network, etc.), or in a System of System (e.g. socio-technical urban service), there are critical elements that, beyond the intrinsic vulnerability, can be characterized by greater or lower vulnerability because of their physical, geographical, cyber or logical connections. To this aim, we propose in this study a comparative analysis between traditional reductionist approach and a new holistic approach to vulnerability assessment to natural hazards. The analysis considers a study case of a socio-economic complex system through an innovative approach based on the properties of graph G=(N,L). A graph consists of two sets N (nodes) and L (links): the nodes represent the single exposed elements (physical, social, environmental, etc.) to a hazard, while the links (or connections) represent the interaction between the elements. The final goal is to illustrate an application of this innovative approach of integrated collective vulnerability assessment.

Atomistic modeling of grain boundary behavior under shear conditions in magnesium and magnesium-based binary alloys

NASA Astrophysics Data System (ADS)

Nahhas, M. K.; Groh, S.

2018-02-01

In this study, the structure, the energetic, and the strength of a { 10 1 bar 1 } < 11 2 bar 0 > symmetric tilt grain boundary in magnesium and magnesium binary alloys were analyzed in the framework of (semi-)empirical potentials. Following a systematic investigation of the transferability and accuracy of the interatomic potentials, atomistic calculations of the grain boundary energy, the grain boundary sliding energy, and the grain boundary strength were performed in pure magnesium and in binary MgX alloys (X = Al, Ca, Gd, Li, Sn, Y, Ag, Nd, and Pb). The data gained in this study were analyzed to identify the most critical material parameters controlling the strength of the grain boundary, and their consequence on atomic shuffling motions occurring at the grain boundary. From the methodology perspective, the role of in-plane and out-of plane relaxation on the grain boundary sliding energy curves was investigated. In pure magnesium, the results showed that in-plane relaxation is critical in activating b2{ 10 1 bar 1 } twinning dislocation resulting in grain boundary migration. In the alloy systems, however, grain boundary migration was disabled as a consequence of the pinning of the grain boundary by segregated elements. Finally, while the grain boundary energy, the shape of the grain boundary sliding energy curves, and the grain boundary sliding energy are critical parameters controlling the grain boundary strength in pure magnesium, only the grain boundary energy and the segregation energy of the alloying elements at the grain boundary were identified as critical material parameters in the alloys system.

Slow crack growth test method for polyethylene gas pipes. Volume 1. Topical report, December 1992

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

Leis, B.; Ahmad, J.; Forte, T.

1992-12-01

In spite of the excellent performance record of polyethylene (PE) pipes used for gas distribution, a small number of leaks occur in distribution systems each year because of slow growth of cracks through pipe walls. The Slow Crack Growth Test (SCG) has been developed as a key element in a methodology for the assessment of the performance of polyethylene gas distribution systems to resist such leaks. This tropical report describes work conducted in the first part of the research directed at the initial development of the SCG test, including a critical evaluation of the applicability of the SCG test asmore » an element in PE gas pipe system performance methodology. Results of extensive experiments and analysis are reported. The results show that the SCG test should be very useful in performance assessment.« less

Using costing as a district planning and management tool in Balochistan, Pakistan.

PubMed

Green, A; Ali, B; Naeem, A; Vassall, A

2001-06-01

This paper reports on two studies in the province of Balochistan, Pakistan, analyzing the costs of primary care facilities and district and divisional hospitals. There are no known previous cost studies within Balochistan and the information gained is a critical element in developing a more rational allocation of resources within the health sector. The results demonstrate both the high level of under-funding of primary care within the health sector and the current inefficiency of allocation towards primary care and, within budgets, between different line items. Medicines in particular are significantly under-funded at the expense of staffing costs. The results are of use in developing more bottom-up budgeting systems within a more rational resource allocation system that is being developed as an element of the more decentralized health system towards which the province is working.

A National Assessment of the Urban Forest: An Overview

Treesearch

John F. Dwyer; David J. Nowak

2000-01-01

Urban forest management promises to play a critical role in the management of .... our nation's forest resources in the 21st century. Urban forests are significant and diverse ecosystems with intricate connections among their physical, biological, and social components; as well as with other elements of urban and natural resource systems. Urban forests are also...

Managing Systemic Curriculum Change: A Critical Analysis of Hong Kong's Target-Oriented Curriculum Initiative.

ERIC Educational Resources Information Center

Carless, David

1997-01-01

Describes Hong Kong's Target-Oriented Curriculum (TOC), a major curriculum renewal initiative designed to improve the quality of learning in local primary schools. Discusses the context in which it was introduced and factors that proved problematic in managing change. Focuses on five elements in the change process: practicality, ownership, teacher…

Schools at the Center of Society's Values and Vision.

ERIC Educational Resources Information Center

Irwin, Kathleen

The critical need for school reform cannot be separated from social reform. It is necessary, therefore, to go beyond the limited scope of curriculum modification to the process of learning how to take every element of an educational experience, raise it to a conscious level, and relate it to a universal struggle around a system of democratic…

Decision-Making Uncertainty and the Use of Force in Cyberspace: A Phenomenological Study of Military Officers

ERIC Educational Resources Information Center

Caudle, Daryl L.

2010-01-01

The nation's critical infrastructure, information systems, and telecommunication networks are vulnerable and threatened by an ever-growing number of attacks in cyberspace. An essential element of the nation's comprehensive approach to cybersecurity is the ability for the Department of Defense to protect and defend its information enterprise.…

The Influence of Transfer System Factors and Training Elapsed Time on Transfer in a Healthcare Organization

ERIC Educational Resources Information Center

Mihalko, Beverly J.

2010-01-01

Organizations and other sponsors of training face increasing pressure to demonstrate the value or impact of their training programs on individual and organizational performance. A critical element in the validation of training effectiveness is the permanent transfer of learned knowledge, skills, and behaviors to the workplace. The generalization…

Carbon cycle observations: gaps threaten climate mitigation policies

Treesearch

Richard Birdsey; Nick Bates; MIke Behrenfeld; Kenneth Davis; Scott C. Doney; Richard Feely; Dennis Hansell; Linda Heath; et al.

2009-01-01

Successful management of carbon dioxide (CO2) requires robust and sustained carbon cycle observations. Yet key elements of a national observation network are lacking or at risk. A U.S. National Research Council review of the U.S. Climate Change Science Program earlier this year highlighted the critical need for a U.S. climate observing system to...

Vision, Leadership, and Change: The Case of Ramah Summer Camps

ERIC Educational Resources Information Center

Reimer, Joseph

2010-01-01

In his retrospective essay, Seymour Fox (1997) identified "vision" as the essential element that shaped the Ramah camp system. I will take a critical look at Fox's main claims: (1) A particular model of vision was essential to the development of Camp Ramah; and (2) That model of vision should guide contemporary Jewish educators in creating Jewish…

Understanding and Using Fiscal Data: A Guide for Part C State Staff

ERIC Educational Resources Information Center

Greer, Maureen; Kilpatrick, Jamie; Nelson, Robin; Reid, Kellen

2014-01-01

This document provides an overview of the critical role of fiscal data in state Part C systems. This information is intended to help state Part C lead agency staff better understand strategic fiscal policy questions, the fiscal data elements needed to address those questions, and the benefits of using these data. Fiscal data provide powerful…

Enhanced Deployment Strategy for Role-Based Hierarchical Application Agents in Wireless Sensor Networks with Established Clusterheads

ERIC Educational Resources Information Center

Gendreau, Audrey

2014-01-01

Efficient self-organizing virtual clusterheads that supervise data collection based on their wireless connectivity, risk, and overhead costs, are an important element of Wireless Sensor Networks (WSNs). This function is especially critical during deployment when system resources are allocated to a subsequent application. In the presented research,…

COST action TD1407: network on technology-critical elements (NOTICE)--from environmental processes to human health threats.

PubMed

Cobelo-García, A; Filella, M; Croot, P; Frazzoli, C; Du Laing, G; Ospina-Alvarez, N; Rauch, S; Salaun, P; Schäfer, J; Zimmermann, S

2015-10-01

The current socio-economic, environmental and public health challenges that countries are facing clearly need common-defined strategies to inform and support our transition to a sustainable economy. Here, the technology-critical elements (which includes Ga, Ge, In, Te, Nb, Ta, Tl, the Platinum Group Elements and most of the rare-earth elements) are of great relevance in the development of emerging key technologies-including renewable energy, energy efficiency, electronics or the aerospace industry. In this context, the increasing use of technology-critical elements (TCEs) and associated environmental impacts (from mining to end-of-life waste products) is not restricted to a national level but covers most likely a global scale. Accordingly, the European COST Action TD1407: Network on Technology-Critical Elements (NOTICE)-from environmental processes to human health threats, has an overall objective for creating a network of scientists and practitioners interested in TCEs, from the evaluation of their environmental processes to understanding potential human health threats, with the aim of defining the current state of knowledge and gaps, proposing priority research lines/activities and acting as a platform for new collaborations and joint research projects. The Action is focused on three major scientific areas: (i) analytical chemistry, (ii) environmental biogeochemistry and (iii) human exposure and (eco)-toxicology.

Solid Rocket Booster (SRB) Flight System Integration at Its Best

NASA Technical Reports Server (NTRS)

Wood, T. David; Kanner, Howard S.; Freeland, Donna M.; Olson, Derek T.

2011-01-01

The Solid Rocket Booster (SRB) element integrates all the subsystems needed for ascent flight, entry, and recovery of the combined Booster and Motor system. These include the structures, avionics, thrust vector control, pyrotechnic, range safety, deceleration, thermal protection, and retrieval systems. This represents the only human-rated, recoverable and refurbishable solid rocket ever developed and flown. Challenges included subsystem integration, thermal environments and severe loads (including water impact), sometimes resulting in hardware attrition. Several of the subsystems evolved during the program through design changes. These included the thermal protection system, range safety system, parachute/recovery system, and others. Because the system was recovered, the SRB was ideal for data and imagery acquisition, which proved essential for understanding loads, environments and system response. The three main parachutes that lower the SRBs to the ocean are the largest parachutes ever designed, and the SRBs are the largest structures ever to be lowered by parachutes. SRB recovery from the ocean was a unique process and represented a significant operational challenge; requiring personnel, facilities, transportation, and ground support equipment. The SRB element achieved reliability via extensive system testing and checkout, redundancy management, and a thorough postflight assessment process. However, the in-flight data and postflight assessment process revealed the hardware was affected much more strongly than originally anticipated. Assembly and integration of the booster subsystems required acceptance testing of reused hardware components for each build. Extensive testing was done to assure hardware functionality at each level of stage integration. Because the booster element is recoverable, subsystems were available for inspection and testing postflight, unique to the Shuttle launch vehicle. Problems were noted and corrective actions were implemented as needed. The postflight assessment process was quite detailed and a significant portion of flight operations. The SRBs provided fully redundant critical systems including thrust vector control, mission critical pyrotechnics, avionics, and parachute recovery system. The design intent was to lift off with full redundancy. On occasion, the redundancy management scheme was needed during flight operations. This paper describes some of the design challenges and technical issues, how the design evolved with time, and key areas where hardware reusability contributed to improved system level understanding.

Engagement and education: care of the critically ill and injured during pandemics and disasters: CHEST consensus statement.

PubMed

Devereaux, Asha V; Tosh, Pritish K; Hick, John L; Hanfling, Dan; Geiling, James; Reed, Mary Jane; Uyeki, Timothy M; Shah, Umair A; Fagbuyi, Daniel B; Skippen, Peter; Dichter, Jeffrey R; Kissoon, Niranjan; Christian, Michael D; Upperman, Jeffrey S

2014-10-01

Engagement and education of ICU clinicians in disaster preparedness is fragmented by time constraints and institutional barriers and frequently occurs during a disaster. We reviewed the existing literature from 2007 to April 2013 and expert opinions about clinician engagement and education for critical care during a pandemic or disaster and offer suggestions for integrating ICU clinicians into planning and response. The suggestions in this article are important for all of those involved in a pandemic or large-scale disaster with multiple critically ill or injured patients, including front-line clinicians, hospital administrators, and public health or government officials. A systematic literature review was performed and suggestions formulated according to the American College of Chest Physicians (CHEST) Consensus Statement development methodology. We assessed articles, documents, reports, and gray literature reported since 2007. Following expert-informed sorting and review of the literature, key priority areas and questions were developed. No studies of sufficient quality were identified upon which to make evidence-based recommendations. Therefore, the panel developed expert opinion-based suggestions using a modified Delphi process. Twenty-three suggestions were formulated based on literature-informed consensus opinion. These suggestions are grouped according to the following thematic elements: (1) situational awareness, (2) clinician roles and responsibilities, (3) education, and (4) community engagement. Together, these four elements are considered to form the basis for effective ICU clinician engagement for mass critical care. The optimal engagement of the ICU clinical team in caring for large numbers of critically ill patients due to a pandemic or disaster will require a departure from the routine independent systems operating in hospitals. An effective response will require robust information systems; coordination among clinicians, hospitals, and governmental organizations; pre-event engagement of relevant stakeholders; and standardized core competencies for the education and training of critical care clinicians.

Virtual test: A student-centered software to measure student's critical thinking on human disease

NASA Astrophysics Data System (ADS)

Rusyati, Lilit; Firman, Harry

2016-02-01

The study "Virtual Test: A Student-Centered Software to Measure Student's Critical Thinking on Human Disease" is descriptive research. The background is importance of computer-based test that use element and sub element of critical thinking. Aim of this study is development of multiple choices to measure critical thinking that made by student-centered software. Instruments to collect data are (1) construct validity sheet by expert judge (lecturer and medical doctor) and professional judge (science teacher); and (2) test legibility sheet by science teacher and junior high school student. Participants consisted of science teacher, lecturer, and medical doctor as validator; and the students as respondent. Result of this study are describe about characteristic of virtual test that use to measure student's critical thinking on human disease, analyze result of legibility test by students and science teachers, analyze result of expert judgment by science teachers and medical doctor, and analyze result of trial test of virtual test at junior high school. Generally, result analysis shown characteristic of multiple choices to measure critical thinking was made by eight elements and 26 sub elements that developed by Inch et al.; complete by relevant information; and have validity and reliability more than "enough". Furthermore, specific characteristic of multiple choices to measure critical thinking are information in form science comic, table, figure, article, and video; correct structure of language; add source of citation; and question can guide student to critical thinking logically.

Sensitivity of the mode locking phenomenon to geometric imperfections during wrinkling of supported thin films

DOE PAGES

Saha, Sourabh K.

2017-01-11

Although geometric imperfections have a detrimental effect on buckling, imperfection sensitivity has not been well studied in the past during design of sinusoidal micro and nano-scale structures via wrinkling of supported thin films. This is likely because one is more interested in predicting the shape/size of the resultant patterns than the buckling bifurcation onset strain during fabrication of such wrinkled structures. Herein, I have demonstrated that even modest geometric imperfections alter the final wrinkled mode shapes via the mode locking phenomenon wherein the imperfection mode grows in exclusion to the natural mode of the system. To study the effect ofmore » imperfections on mode locking, I have (i) developed a finite element mesh perturbation scheme to generate arbitrary geometric imperfections in the system and (ii) performed a parametric study via finite element methods to link the amplitude and period of the sinusoidal imperfections to the observed wrinkle mode shape and size. Based on this, a non-dimensional geometric parameter has been identified that characterizes the effect of imperfection on the mode locking phenomenon – the equivalent imperfection size. An upper limit for this equivalent imperfection size has been identified via a combination of analytical and finite element modeling. During compression of supported thin films, the system gets “locked” into the imperfection mode if its equivalent imperfection size is above this critical limit. For the polydimethylsiloxane/glass bilayer with a wrinkle period of 2 µm, this mode lock-in limit corresponds to an imperfection amplitude of 32 nm for an imperfection period of 5 µm and 8 nm for an imperfection period of 0.8 µm. Interestingly, when the non-dimensional critical imperfection size is scaled by the bifurcation onset strain, the scaled critical size depends solely on the ratio of the imperfection to natural periods. Furthermore, the computational data generated here can be generalized beyond the specific natural periods and bilayer systems studied to enable deterministic design of a variety of wrinkled micro and nano-scale structures.« less

Cryogenic propellant management: Integration of design, performance and operational requirements

NASA Technical Reports Server (NTRS)

Worlund, A. L.; Jamieson, J. R., Jr.; Cole, T. W.; Lak, T. I.

1985-01-01

The integration of the design features of the Shuttle elements into a cryogenic propellant management system is described. The implementation and verification of the design/operational changes resulting from design deficiencies and/or element incompatibilities encountered subsequent to the critical design reviews are emphasized. Major topics include: subsystem designs to provide liquid oxygen (LO2) tank pressure stabilization, LO2 facility vent for ice prevention, liquid hydrogen (LH2) feedline high point bleed, pogo suppression on the Space Shuttle Main Engine (SSME), LO2 low level cutoff, Orbiter/engine propellant dump, and LO2 main feedline helium injection for geyser prevention.

Satellite Power Systems /SPS/ - Overview of system studies and critical technology

NASA Technical Reports Server (NTRS)

Manson, S. V.

1980-01-01

Systems studies and critical technology issues for the development and evaluation of Satellite Power Systems (SPS) for the photovoltaic generation of electrical energy and its transmission to earth are reviewed. Initial concept studies completed in 1976 and system definition studies initiated in the same year have indicated the technical feasibility of SPS and identified challenging issues to be addressed as part of the SPS Concept Development and Evaluation Program. Systems considered in the study include photovoltaic and solar thermal power conversion configurations employing klystron or solid state microwave generators or lasers for power transmission, and power transmission options, system constructability and in-orbit and ground operations. Technology investigations are being performed in the areas of microwave power transmission, structure/controls interactions and the behavior of key materials in the space/SPS environment. Favorable results have been obtained in the areas of microwave phase distribution and phase control, dc-RF conversion, antenna radiating element, and no insurmountable problems have been discovered in any of the investigations to date.

Critical Elements in Reservoir Rocks of Produced Fluids Nevada and Utah August 2017

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

Simmons, Stuart

Critical and trace element data for drill cuttings from Beowawe, Dixie Valley, and Roosevelt Hot Springs-Blundell geothermal production fields, for drill cuttings from Uinta basin producing oil-gas wells, and from outcrops in the Sevier Thermal Anomaly-Utah.

5 CFR 430.203 - Definitions.

Code of Federal Regulations, 2010 CFR

2010-01-01

... aspect of individual, team, or organizational performance that is not a critical or non-critical element..., are useful for purposes such as communicating performance expectations and serving as the basis for granting awards. Such elements may include, but are not limited to, objectives, goals, program plans, work...

Ore Deposits Mined for Critical Elements

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

Verplanck, Philip; Kelley, Karen

Summary of deposit types containing critical elements, including, cobalt, gallium, germanium, indium, niobium, PGE, REE, rhenium, selenium, and tellurium. Includes information about ore deposit type, mineralogy, geologic setting, example deposits and districts, concentration ranges per reported resource, grade, and additional deposit notes. References are also included.

Design for Safety - The Ares Launch Vehicles Paradigm Change

NASA Technical Reports Server (NTRS)

Safie, Fayssal M.; Maggio, Gaspare

2010-01-01

The lessons learned from the S&MA early involvement in the Ares I launch vehicle design phases proved that performing an in-line function jointly with engineering is critical for S&MA to have an effective role in supporting the system, element, and component design. These lessons learned were used to effectively support the Ares V conceptual design phase and planning for post conceptual design phases. The Top level Conceptual LOM assessment for Ares V performed by the S&MA community jointly with the engineering Advanced Concept Office (ACO) was influential in the final selection of the Ares V system configuration. Post conceptual phase, extensive reliability effort should be planned to support future Heavy Lift Launch Vehicles (HLLV) design. In-depth reliability analysis involving the design, manufacturing, and system engineering communities is critical to understand design and process uncertainties and system integrated failures.

CFD modeling of thermoelectric generators in automotive EGR-coolers

NASA Astrophysics Data System (ADS)

Högblom, Olle; Andersson, Ronnie

2012-06-01

A large amount of the waste heat in the exhaust gases from diesel engines is removed in the exhaust gas recirculation (EGR) cooler. Introducing a thermoelectric generator (TEG) in an EGR cooler requires a completely new design of the heat exchanger. To accomplish that a model of the TEG-EGR system is required. In this work, a transient 3D CFD model for simulation of gas flow, heat transfer and power generation has been developed. This model allows critical design parameters in the TEG-EGR to be identified and design requirements for the systems to be specified. Besides the prediction of Seebeck, Peltier, Thomson and Joule effects, the simulations also give detailed insight to the temperature gradients in the gas-phase and inside the thermoelectric (TE) elements. The model is a very valuable tool to identify bottlenecks, improve design, select optimal TE materials and operating conditions. The results show that the greatest heat transfer resistance is located in the gas phase and it is critical to reduce this in order to achieve a large temperature difference over the thermoelectric elements without compromising on the maximum allowable pressure drop in the system. Further results from an investigation of the thermoelectric performance during a vehicle test cycle is presented.

EMD-Based Methodology for the Identification of a High-Speed Train Running in a Gear Operating State.

PubMed

Bustos, Alejandro; Rubio, Higinio; Castejón, Cristina; García-Prada, Juan Carlos

2018-03-06

An efficient maintenance is a key consideration in systems of railway transport, especially in high-speed trains, in order to avoid accidents with catastrophic consequences. In this sense, having a method that allows for the early detection of defects in critical elements, such as the bogie mechanical components, is a crucial for increasing the availability of rolling stock and reducing maintenance costs. The main contribution of this work is the proposal of a methodology that, based on classical signal processing techniques, provides a set of parameters for the fast identification of the operating state of a critical mechanical system. With this methodology, the vibratory behaviour of a very complex mechanical system is characterised, through variable inputs, which will allow for the detection of possible changes in the mechanical elements. This methodology is applied to a real high-speed train in commercial service, with the aim of studying the vibratory behaviour of the train (specifically, the bogie) before and after a maintenance operation. The results obtained with this methodology demonstrated the usefulness of the new procedure and allowed for the disclosure of reductions between 15% and 45% in the spectral power of selected Intrinsic Mode Functions (IMFs) after the maintenance operation.

EMD-Based Methodology for the Identification of a High-Speed Train Running in a Gear Operating State

PubMed Central

García-Prada, Juan Carlos

2018-01-01

An efficient maintenance is a key consideration in systems of railway transport, especially in high-speed trains, in order to avoid accidents with catastrophic consequences. In this sense, having a method that allows for the early detection of defects in critical elements, such as the bogie mechanical components, is a crucial for increasing the availability of rolling stock and reducing maintenance costs. The main contribution of this work is the proposal of a methodology that, based on classical signal processing techniques, provides a set of parameters for the fast identification of the operating state of a critical mechanical system. With this methodology, the vibratory behaviour of a very complex mechanical system is characterised, through variable inputs, which will allow for the detection of possible changes in the mechanical elements. This methodology is applied to a real high-speed train in commercial service, with the aim of studying the vibratory behaviour of the train (specifically, the bogie) before and after a maintenance operation. The results obtained with this methodology demonstrated the usefulness of the new procedure and allowed for the disclosure of reductions between 15% and 45% in the spectral power of selected Intrinsic Mode Functions (IMFs) after the maintenance operation. PMID:29509690

Solid Rocket Booster (SRB) - Evolution and Lessons Learned During the Shuttle Program

NASA Technical Reports Server (NTRS)

Kanner, Howard S.; Freeland, Donna M.; Olson, Derek T.; Wood, T. David; Vaccaro, Mark V.

2011-01-01

The Solid Rocket Booster (SRB) element integrates all the subsystems needed for ascent flight, entry, and recovery of the combined Booster and Motor system. These include the structures, avionics, thrust vector control, pyrotechnic, range safety, deceleration, thermal protection, and retrieval systems. This represents the only human-rated, recoverable and refurbishable solid rocket ever developed and flown. Challenges included subsystem integration, thermal environments and severe loads (including water impact), sometimes resulting in hardware attrition. Several of the subsystems evolved during the program through design changes. These included the thermal protection system, range safety system, parachute/recovery system, and others. Obsolescence issues occasionally required component recertification. Because the system was recovered, the SRB was ideal for data and imagery acquisition, which proved essential for understanding loads and system response. The three main parachutes that lower the SRBs to the ocean are the largest parachutes ever designed, and the SRBs are the largest structures ever to be lowered by parachutes. SRB recovery from the ocean was a unique process and represented a significant operational challenge; requiring personnel, facilities, transportation, and ground support equipment. The SRB element achieved reliability via extensive system testing and checkout, redundancy management, and a thorough postflight assessment process. Assembly and integration of the booster subsystems was a unique process and acceptance testing of reused hardware components was required for each build. Extensive testing was done to assure hardware functionality at each level of stage integration. Because the booster element is recoverable, subsystems were available for inspection and testing postflight, unique to the Shuttle launch vehicle. Problems were noted and corrective actions were implemented as needed. The postflight assessment process was quite detailed and a significant portion of flight operations. The SRBs provided fully redundant critical systems including thrust vector control, mission critical pyrotechnics, avionics, and parachute recovery system. The design intent was to lift off with full redundancy. On occasion, the redundancy management scheme was needed during flight operations. This paper describes some of the design challenges, how the design evolved with time, and key areas where hardware reusability contributed to improved system level understanding.

Solar Sea Power Plants (SSPP): A critical review and survey

NASA Technical Reports Server (NTRS)

Strauss, A. M.

1974-01-01

An overview of technical and economic matters relating to the eventual success or failure of the SSPP concept is presented, with emphasis on the pollution and energy problems which the SSPP would serve to eliminate. Factors discussed include cost, mariculture possibilities, siting, legal limitations, design materials, mooring and anchoring, and the human element involved. Several alternative power systems are considered for incorporation into SSPP design, such as Nitinol power, Claude cycle, and closed cycle engine systems.

Key elements of successful care process of patients with heart symptoms in an emergency care - could an ERP system help?

PubMed

Kontio, Elina; Korvenranta, Heikki; Lundgren-Laine, Heljä; Salanterä, Sanna

2009-01-01

The aim of the study was to identify key elements of successful care process of patients with heart symptoms from the nursing management viewpoint in an emergency care. Through these descriptions, we aimed at identifying possibilities for using enterprise resource planning (ERP) systems to support decision making in emergency care. Hospitals are increasingly moving to process-based workings and at the same time new information system in healthcare are developed and therefore it is essential to understand the strengths and weaknesses of current processes better. A qualitative descriptive design using critical incident technique was employed. Critical Incidents were collected with an open-ended questionnaire. The sample (n=50), 13 head nurses and 37 registered nurses, was purposeful selected from three acute hospitals in southern Finland. The process of patients with heart symptoms in emergency care was described. We identified three competence categories where special focus should be placed to achieve successful process of patients with heart symptoms: process-oriented competencies, personal/management competencies and logistics oriented competencies. Improvement of decision making requires that the care processes are defined and modeled. The research showed that there are several happenings in emergency care where an ERP system could help and support decision making. These happenings can be categorized in two groups: 1) administrative related happenings and 2) patient processes related happenings.

Orion GN and C Overview and Architecture

NASA Technical Reports Server (NTRS)

Hu, Howard; Straube, Tim

2007-01-01

The Crew Exploration Vehicle, named Orion, is a critical element in the Constellation Program to develop the transportation system needed to send humans back to the moon and then beyond. Lockheed Martin is the prime contractor for the Orion spacecraft, which is managed by the Johnson Space Center. The Orion GN&C sub-system is being jointly developed by NASA and Lockheed Martin through a mode team approach. The GN&C is a critical element of the Orion mission to carry astronauts to low earth orbit to service the International Space Station and then on later flights to transfer and return a crew of four to the moon. The Orion GN&C system must perform monitoring and abort functions during ascent, rendezvous and docking in both low earth and lunar orbits, perform uncrewed lunar loiter operations, perform trans earth injection and atmospheric entry and landing. The Orion also must be integrated with the Ares I Crew Launch Vehicle, the Earth Departure Stage of the Ares V and the Lunar Surface Access Module. This paper provides an overview of the Orion GN&C system. The functional capabilities of the Orion GN&C will be provided in the context of Constellation architecture, the key GN&C requirements will be summarized, the GN&C architecture will be presented, the development schedule and plans will summarized and finally conclusions will be presented.

"If donors woke up tomorrow and said we can't fund you, what would we do?" A health system dynamics analysis of implementation of PMTCT option B+ in Uganda.

PubMed

Doherty, Tanya; Besada, Donnela; Goga, Ameena; Daviaud, Emmanuelle; Rohde, Sarah; Raphaely, Nika

2017-07-26

In October 2012 Uganda extended its prevention of mother to child HIV transmission (PMTCT) policy to Option B+, providing lifelong antiretroviral treatment for HIV positive pregnant and breastfeeding women. The rapid changes and adoptions of new PMTCT policies have not been accompanied by health systems research to explore health system preparedness to implement such programmes. The implementation of Option B+ provides many lessons which can inform the shift to 'Universal Test and Treat', a policy which many sub-Saharan African countries are preparing to adopt, despite fragile health systems. This qualitative study of PMTCT Option B+ implementation in Uganda three years following the policy adoption, uses the health system dynamics framework to explore the impacts of this programme on ten elements of the health system. Qualitative data were gathered through rapid appraisal during in-country field work. Key informant interviews and focus group discussions (FGDs) were undertaken with the Ministry of Health, implementing partners, multilateral agencies, district management teams, facility-based health workers and community cadres. A total of 82 individual interviews and 16 focus group discussions were completed. We conducted a simple manifest analysis, using the ten elements of a health system for grouping data into categories and themes. Of the ten elements in the health system dynamics framework, context and resources (finances, infrastructure & supplies, and human resources) were the most influential in the implementation of Option B+ in Uganda. Support from international actors and implementing partners attempted to strengthen resources at district level, but had unintended consequences of creating dependence and uncertainty regarding sustainability. The health system dynamics framework offers a novel approach to analysis of the effects of implementation of a new policy on critical elements of the health system. Its emphasis on relationships between system elements, population and context is helpful in unpacking impacts of and reactions to pressures on the system, which adds value beyond some previous frameworks.

Interfacial characterization of ceramic core materials with veneering porcelain for all-ceramic bi-layered restorative systems.

PubMed

Tagmatarchis, Alexander; Tripodakis, Aris-Petros; Filippatos, Gerasimos; Zinelis, Spiros; Eliades, George

2014-01-01

The aim of the study was to characterize the elemental distribution at the interface between all-ceramic core and veneering porcelain materials. Three groups of all-ceramic cores were selected: A) Glass-ceramics (Cergo, IPS Empress, IPS Empress 2, e-max Press, Finesse); B) Glass-infiltrated ceramics (Celay Alumina, Celay Zirconia) and C) Densely sintered ceramics (Cercon, Procera Alumina, ZirCAD, Noritake Zirconia). The cores were combined with compatible veneering porcelains and three flat square test specimens were produced for each system. The core-veneer interfaces were examined by scanning electron microscopy and energy dispersive x-ray microanalysis. The glass-ceramic systems showed interfacial zones reach in Si and O, with the presence of K, Ca, Al in core and Ca, Ce, Na, Mg or Al in veneer material, depending on the system tested. IPS Empress and IPS Empress 2 demonstrated distinct transitional phases at the core-veneer interface. In the glassinfiltrated systems, intermixing of core (Ce, La) with veneer (Na, Si) elements occurred, whereas an abrupt drop of the core-veneer elemental concentration was documented at the interfaces of all densely sintered ceramics. The results of the study provided no evidence of elemental interdiffusion at the core-veneer interfaces in densely sintered ceramics, which implies lack of primary chemical bonding. For the glass-containing systems (glassceramics and glass-infiltrated ceramics) interdiffusion of the glass-phase seems to play a critical role in establishing a primary bonding condition between ceramic core and veneering porcelain.

The chemical behavior of the transuranic elements and the barrier function in natural aquifer systems

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

Jewett, J.R.

1997-09-17

In a geological repository for long-lived radioactive wastes, such as actinides and certain fission products, most of the stored radionuclides remain immobile in the particular geological formation. If any of these could possibly become mobile, only trace concentrations of a few radionuclides would result. Nevertheless, with an inventory in the repository of many tonnes of transuranic elements, the amounts that could disperse cannot be neglected. A critical assessment of the chemical behavior of these nuclides, especially their migration properties in the aquifer system around the repository site, is mandatory for analysis of the long-term safety. The chemistry requited for thismore » includes many geochemical multicomponent reactions that are so far only partially understood and [which] therefore can be quantified only incompletely. A few of these reactions have been discussed in this paper based on present knowledge. If a comprehensive discussion of the subject is impossible because of this [lack of information], then an attempt to emphasize the importance of the predominant geochemical reactions of the transuranic elements in various aquifer systems should be made.« less

The goldstone real-time connected element interferometer

NASA Technical Reports Server (NTRS)

Edwards, C., Jr.; Rogstad, D.; Fort, D.; White, L.; Iijima, B.

1992-01-01

Connected element interferometry (CEI) is a technique of observing a celestial radio source at two spatially separated antennas and then interfering the received signals to extract the relative phase of the signal at the two antennas. The high precision of the resulting phase delay data type can provide an accurate determination of the angular position of the radio source relative to the baseline vector between the two stations. This article describes a recently developed connected element interferometer on a 21-km baseline between two antennas at the Deep Space Network's Goldstone, California, tracking complex. Fiber-optic links are used to transmit the data to a common site for processing. The system incorporates a real-time correlator to process these data in real time. The architecture of the system is described, and observational data are presented to characterize the potential performance of such a system. The real-time processing capability offers potential advantages in terms of increased reliability and improved delivery of navigational data for time-critical operations. Angular accuracies of 50-100 nrad are achievable on this baseline.

The Gut as the Motor of Multiple Organ Dysfunction in Critical Illness

PubMed Central

Klingensmith, Nathan J.; Coopersmith, Craig M.

2015-01-01

Synopsis All elements of the gut – the epithelium, the immune system, and the microbiome – are impacted by critical illness and can, in turn, propagate a pathologic host response leading to multiple organ dysfunction syndrome. Preclinical studies have demonstrated that this can occur by release of toxic gut-derived substances into the mesenteric lymph where they can cause distant damage. Further, intestinal integrity is compromised in critical illness with increases in apoptosis and permeability. There is also increasing recognition that microbes alter their behavior and can become virulent based upon host environmental cues. Gut failure is common in critically ill patients; however, therapeutics targeting the gut have proven to be challenging to implement at the bedside. Numerous strategies to manipulate the microbiome have recently been used with varying success in the ICU. PMID:27016162

The Gut as the Motor of Multiple Organ Dysfunction in Critical Illness.

PubMed

Klingensmith, Nathan J; Coopersmith, Craig M

2016-04-01

All elements of the gut - the epithelium, the immune system, and the microbiome - are impacted by critical illness and can, in turn, propagate a pathologic host response leading to multiple organ dysfunction syndrome. Preclinical studies have demonstrated that this can occur by release of toxic gut-derived substances into the mesenteric lymph where they can cause distant damage. Further, intestinal integrity is compromised in critical illness with increases in apoptosis and permeability. There is also increasing recognition that microbes alter their behavior and can become virulent based upon host environmental cues. Gut failure is common in critically ill patients; however, therapeutics targeting the gut have proven to be challenging to implement at the bedside. Numerous strategies to manipulate the microbiome have recently been used with varying success in the ICU. Copyright © 2016 Elsevier Inc. All rights reserved.

Can a digital medicine system improve adherence to antipsychotic treatment?

PubMed

Papola, D; Gastaldon, C; Ostuzzi, G

2018-06-01

A substantial proportion of people with mental health conditions do not adhere to prescribed pharmacological treatments. Poor adherence is probably one of the most critical elements contributing to relapse in people with schizophrenia and other severe mental disorders. In order to tackle this global issue, in November 2017 the Food and Drug Administration approved a tablet formulation of the atypical antipsychotic aripiprazole embedded with a novel digital adherence-assessment device. In this commentary, we critically appraised the potential beneficial and harmful consequences of this new digital formulation of aripiprazole, and we highlighted expected implications for clinical practice.

NASA Stennis Space Center Integrated System Health Management Test Bed and Development Capabilities

NASA Technical Reports Server (NTRS)

Figueroa, Fernando; Holland, Randy; Coote, David

2006-01-01

Integrated System Health Management (ISHM) is a capability that focuses on determining the condition (health) of every element in a complex System (detect anomalies, diagnose causes, prognosis of future anomalies), and provide data, information, and knowledge (DIaK)-not just data-to control systems for safe and effective operation. This capability is currently done by large teams of people, primarily from ground, but needs to be embedded on-board systems to a higher degree to enable NASA's new Exploration Mission (long term travel and stay in space), while increasing safety and decreasing life cycle costs of spacecraft (vehicles; platforms; bases or outposts; and ground test, launch, and processing operations). The topics related to this capability include: 1) ISHM Related News Articles; 2) ISHM Vision For Exploration; 3) Layers Representing How ISHM is Currently Performed; 4) ISHM Testbeds & Prototypes at NASA SSC; 5) ISHM Functional Capability Level (FCL); 6) ISHM Functional Capability Level (FCL) and Technology Readiness Level (TRL); 7) Core Elements: Capabilities Needed; 8) Core Elements; 9) Open Systems Architecture for Condition-Based Maintenance (OSA-CBM); 10) Core Elements: Architecture, taxonomy, and ontology (ATO) for DIaK management; 11) Core Elements: ATO for DIaK Management; 12) ISHM Architecture Physical Implementation; 13) Core Elements: Standards; 14) Systematic Implementation; 15) Sketch of Work Phasing; 16) Interrelationship Between Traditional Avionics Systems, Time Critical ISHM and Advanced ISHM; 17) Testbeds and On-Board ISHM; 18) Testbed Requirements: RETS AND ISS; 19) Sustainable Development and Validation Process; 20) Development of on-board ISHM; 21) Taxonomy/Ontology of Object Oriented Implementation; 22) ISHM Capability on the E1 Test Stand Hydraulic System; 23) Define Relationships to Embed Intelligence; 24) Intelligent Elements Physical and Virtual; 25) ISHM Testbeds and Prototypes at SSC Current Implementations; 26) Trailer-Mounted RETS; 27) Modeling and Simulation; 28) Summary ISHM Testbed Environments; 29) Data Mining - ARC; 30) Transitioning ISHM to Support NASA Missions; 31) Feature Detection Routines; 32) Sample Features Detected in SSC Test Stand Data; and 33) Health Assessment Database (DIaK Repository).

Prediction of strain values in reinforcements and concrete of a RC frame using neural networks

NASA Astrophysics Data System (ADS)

Vafaei, Mohammadreza; Alih, Sophia C.; Shad, Hossein; Falah, Ali; Halim, Nur Hajarul Falahi Abdul

2018-03-01

The level of strain in structural elements is an important indicator for the presence of damage and its intensity. Considering this fact, often structural health monitoring systems employ strain gauges to measure strains in critical elements. However, because of their sensitivity to the magnetic fields, inadequate long-term durability especially in harsh environments, difficulties in installation on existing structures, and maintenance cost, installation of strain gauges is not always possible for all structural components. Therefore, a reliable method that can accurately estimate strain values in critical structural elements is necessary for damage identification. In this study, a full-scale test was conducted on a planar RC frame to investigate the capability of neural networks for predicting the strain values. Two neural networks each of which having a single hidden layer was trained to relate the measured rotations and vertical displacements of the frame to the strain values measured at different locations of the frame. Results of trained neural networks indicated that they accurately estimated the strain values both in reinforcements and concrete. In addition, the trained neural networks were capable of predicting strains for the unseen input data set.

A quantitative metric to identify critical elements within seafood supply networks.

PubMed

Plagányi, Éva E; van Putten, Ingrid; Thébaud, Olivier; Hobday, Alistair J; Innes, James; Lim-Camacho, Lilly; Norman-López, Ana; Bustamante, Rodrigo H; Farmery, Anna; Fleming, Aysha; Frusher, Stewart; Green, Bridget; Hoshino, Eriko; Jennings, Sarah; Pecl, Gretta; Pascoe, Sean; Schrobback, Peggy; Thomas, Linda

2014-01-01

A theoretical basis is required for comparing key features and critical elements in wild fisheries and aquaculture supply chains under a changing climate. Here we develop a new quantitative metric that is analogous to indices used to analyse food-webs and identify key species. The Supply Chain Index (SCI) identifies critical elements as those elements with large throughput rates, as well as greater connectivity. The sum of the scores for a supply chain provides a single metric that roughly captures both the resilience and connectedness of a supply chain. Standardised scores can facilitate cross-comparisons both under current conditions as well as under a changing climate. Identification of key elements along the supply chain may assist in informing adaptation strategies to reduce anticipated future risks posed by climate change. The SCI also provides information on the relative stability of different supply chains based on whether there is a fairly even spread in the individual scores of the top few key elements, compared with a more critical dependence on a few key individual supply chain elements. We use as a case study the Australian southern rock lobster Jasus edwardsii fishery, which is challenged by a number of climate change drivers such as impacts on recruitment and growth due to changes in large-scale and local oceanographic features. The SCI identifies airports, processors and Chinese consumers as the key elements in the lobster supply chain that merit attention to enhance stability and potentially enable growth. We also apply the index to an additional four real-world Australian commercial fishery and two aquaculture industry supply chains to highlight the utility of a systematic method for describing supply chains. Overall, our simple methodological approach to empirically-based supply chain research provides an objective method for comparing the resilience of supply chains and highlighting components that may be critical.

A Quantitative Metric to Identify Critical Elements within Seafood Supply Networks

PubMed Central

Plagányi, Éva E.; van Putten, Ingrid; Thébaud, Olivier; Hobday, Alistair J.; Innes, James; Lim-Camacho, Lilly; Norman-López, Ana; Bustamante, Rodrigo H.; Farmery, Anna; Fleming, Aysha; Frusher, Stewart; Green, Bridget; Hoshino, Eriko; Jennings, Sarah; Pecl, Gretta; Pascoe, Sean; Schrobback, Peggy; Thomas, Linda

2014-01-01

A theoretical basis is required for comparing key features and critical elements in wild fisheries and aquaculture supply chains under a changing climate. Here we develop a new quantitative metric that is analogous to indices used to analyse food-webs and identify key species. The Supply Chain Index (SCI) identifies critical elements as those elements with large throughput rates, as well as greater connectivity. The sum of the scores for a supply chain provides a single metric that roughly captures both the resilience and connectedness of a supply chain. Standardised scores can facilitate cross-comparisons both under current conditions as well as under a changing climate. Identification of key elements along the supply chain may assist in informing adaptation strategies to reduce anticipated future risks posed by climate change. The SCI also provides information on the relative stability of different supply chains based on whether there is a fairly even spread in the individual scores of the top few key elements, compared with a more critical dependence on a few key individual supply chain elements. We use as a case study the Australian southern rock lobster Jasus edwardsii fishery, which is challenged by a number of climate change drivers such as impacts on recruitment and growth due to changes in large-scale and local oceanographic features. The SCI identifies airports, processors and Chinese consumers as the key elements in the lobster supply chain that merit attention to enhance stability and potentially enable growth. We also apply the index to an additional four real-world Australian commercial fishery and two aquaculture industry supply chains to highlight the utility of a systematic method for describing supply chains. Overall, our simple methodological approach to empirically-based supply chain research provides an objective method for comparing the resilience of supply chains and highlighting components that may be critical. PMID:24633147

Parental Psychological Control Dimensions: Connections with Russian Preschoolers' Physical and Relational Aggression

ERIC Educational Resources Information Center

Nelson, David A.; Yang, Chongming; Coyne, Sarah M.; Olsen, Joseph A.; Hart, Craig H.

2013-01-01

Parental psychological control generally consists of overinvolved/protective and critical/rejecting elements, both being linked to children's psychosocial maladjustment. The critical/rejecting element is multidimensional in nature, and few studies have explored this conceptual fullness. It is possible that some dimensions, if they can be…

Dynamics of a discrete chain of bi-stable elements: A biomimetic shock absorbing mechanism

NASA Astrophysics Data System (ADS)

Cohen, T.; Givli, S.

2014-03-01

A biomimetic shock absorbing mechanism, inspired by the bi-stable elongation behavior of the giant protein titin, is examined. A bi-stable element, composed of three mass particles with monotonous interaction forces, is suggested to facilitate an internal degree of freedom of finite mass which contributes significantly to dissipation upon unlocking of an internal link. An essential feature of the suggested element is that it undergoes reversible rapture and therefore retrieves its initial configuration once unloaded. The quasistatic and dynamic behaviors are investigated showing similarity to the common tri-linear bi-stable response, with two steady phases separated by a spinodal region. The dynamic behavior of a chain of elements is also examined, for several loading scenarios, showing that the suggested mechanism serves as an efficient shock absorber in a sub-critical dampening environment, as compared with a simple mass on spring system. Propagation of shock waves and refraction waves in an element chain is observed and the effect of natural imperfections is considered.

[Structural elements of critical thinking of nurses in emergency care].

PubMed

Crossetti, Maria da Graça Oliveira; Bittencourt, Greicy Kelly Gouveia Dias; Lima, Ana Amélia Antunes; de Góes, Marta Georgina Oliveira; Saurin, Gislaine

2014-09-01

The objective of this study was to analyze the structural elements of critical thinking (CT) of nurses in the clinical decision-making process. This exploratory, qualitative study was conducted with 20 emergency care nurses in three hospitals in southern Brazil. Data were collected from April to June 2009, and a validated clinical case was applied from which nurses listed health problems, prescribed care and listed the structural elements of CT. Content analysis resulted in categories used to determine priority structural elements of CT, namely theoretical foundations and practical relationship to clinical decision making; technical and scientific knowledge and clinical experience, thought processes and clinical decision making: clinical reasoning and basis for clinical judgments of nurses: patient assessment and ethics. It was concluded that thinking critically is a skill that enables implementation of a secure and effective nursing care process.

Terminological aspects of data elements

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

Strehlow, R.A.; Kenworthey, W.H. Jr.; Schuldt, R.E.

1991-01-01

The creation and display of data comprise a process that involves a sequence of steps requiring both semantic and systems analysis. An essential early step in this process is the choice, definition, and naming of data element concepts and is followed by the specification of other needed data element concept attributes. The attributes and the values of data element concept remain associated with them from their birth as a concept to a generic data element that serves as a template for final application. Terminology is, therefore, centrally important to the entire data creation process. Smooth mapping from natural language tomore » a database is a critical aspect of database, and consequently, it requires terminology standardization from the outset of database work. In this paper the semantic aspects of data elements are analyzed and discussed. Seven kinds of data element concept information are considered and those that require terminological development and standardization are identified. The four terminological components of a data element are the hierarchical type of a concept, functional dependencies, schematas showing conceptual structures, and definition statements. These constitute the conventional role of terminology in database design. 12 refs., 8 figs., 1 tab.« less

Density and mixture fraction measurements in a GO2/GH2 uni-element rocket chamber

NASA Technical Reports Server (NTRS)

Moser, M. D.; Pal, S.; Santoro, R. J.

1994-01-01

In recent years, there has been a renewed interest in gas/gas injectors for rocket combustion. Specifically, the proposed new concept of full-flow oxygen rich preburner systems calls for the injection of both oxygen and hydrogen into the main chamber as gaseous propellants. The technology base for gas/gas injection must mature before actual booster class systems can be designed and fabricated. Since the data base for gas/gas injection is limited to studies focusing on the global parameters of small reaction engines, there is a critical need for experiment programs that emphasize studying the mixing and combustion characteristics of GO2 and GH2 propellants from a uni-element injector point of view. The experimental study of the combusting GO2/GH2 propellant combination in a uni-element rocket chamber also provides a simplified environment, in terms of both geometry and chemistry, that can be used to verify and validate computational fluid dynamic (CFD) models.

NEUTRONIC REACTOR CORE

DOEpatents

Thomson, W.B.; Corbin, A. Jr.

1961-07-18

An improved core for a gas-cooled power reactor which admits gas coolant at high temperatures while affording strong integral supporting structure and efficient moderation of neutrons is described. The multiplicities of fuel elements constituting the critical amassment of fissionable material are supported and confined by a matrix of metallic structure which is interspersed therebetween. Thermal insulation is interposed between substantially all of the metallic matrix and the fuel elements; the insulation then defines the principal conduit system for conducting the coolant gas in heat-transfer relationship with the fuel elements. The metallic matrix itseif comprises a system of ducts through which an externally-cooled hydrogeneous liquid, such as water, is circulated to serve as the principal neutron moderant for the core and conjointly as the principal coolant for the insulated metallic structure. In this way, use of substantially neutron transparent metals, such as aluminum, becomes possible for the supporting structure, despite the high temperatures of the proximate gas. The Aircraft Nuclear Propulsion program's "R-1" reactor design is a preferred embodiment.

Epidermal Growth Factor Signaling towards Proliferation: Modeling and Logic Inference Using Forward and Backward Search

PubMed Central

Riesco, Adrián; Santos-Buitrago, Beatriz; De Las Rivas, Javier; Knapp, Merrill; Talcott, Carolyn

2017-01-01

In biological systems, pathways define complex interaction networks where multiple molecular elements are involved in a series of controlled reactions producing responses to specific biomolecular signals. These biosystems are dynamic and there is a need for mathematical and computational methods able to analyze the symbolic elements and the interactions between them and produce adequate readouts of such systems. In this work, we use rewriting logic to analyze the cellular signaling of epidermal growth factor (EGF) and its cell surface receptor (EGFR) in order to induce cellular proliferation. Signaling is initiated by binding the ligand protein EGF to the membrane-bound receptor EGFR so as to trigger a reactions path which have several linked elements through the cell from the membrane till the nucleus. We present two different types of search for analyzing the EGF/proliferation system with the help of Pathway Logic tool, which provides a knowledge-based development environment to carry out the modeling of the signaling. The first one is a standard (forward) search. The second one is a novel approach based on narrowing, which allows us to trace backwards the causes of a given final state. The analysis allows the identification of critical elements that have to be activated to provoke proliferation. PMID:28191459

Epidermal Growth Factor Signaling towards Proliferation: Modeling and Logic Inference Using Forward and Backward Search.

PubMed

Riesco, Adrián; Santos-Buitrago, Beatriz; De Las Rivas, Javier; Knapp, Merrill; Santos-García, Gustavo; Talcott, Carolyn

2017-01-01

In biological systems, pathways define complex interaction networks where multiple molecular elements are involved in a series of controlled reactions producing responses to specific biomolecular signals. These biosystems are dynamic and there is a need for mathematical and computational methods able to analyze the symbolic elements and the interactions between them and produce adequate readouts of such systems. In this work, we use rewriting logic to analyze the cellular signaling of epidermal growth factor (EGF) and its cell surface receptor (EGFR) in order to induce cellular proliferation. Signaling is initiated by binding the ligand protein EGF to the membrane-bound receptor EGFR so as to trigger a reactions path which have several linked elements through the cell from the membrane till the nucleus. We present two different types of search for analyzing the EGF/proliferation system with the help of Pathway Logic tool, which provides a knowledge-based development environment to carry out the modeling of the signaling. The first one is a standard (forward) search. The second one is a novel approach based on narrowing , which allows us to trace backwards the causes of a given final state. The analysis allows the identification of critical elements that have to be activated to provoke proliferation.

Learning from Experience: A Cross-Case Comparison of School-to-Work Transition Reform Initiatives.

ERIC Educational Resources Information Center

Rogers, Anne M.; And Others

A cross-case study approach was used to determine how school-to-work reform affects clients and participants and to identify elements critical to the success of school-to-work systems. Fourteen school-to-work reform initiatives in communities across the United States were examined by using a research protocol that included individual interviews,…

Review and critical analysis: Rolling-element bearings for system life and reliability

NASA Technical Reports Server (NTRS)

Irwin, A. S.; Anderson, W. J.; Derner, W. J.

1985-01-01

A ball and cylindrical roller bearing technical specification which incorporates the latest state-of-the-art advancements was prepared for the purpose of improving bearing reliability in U.S. Army aircraft. The current U.S. Army aviation bearing designs and applications, including life analyses, were analyzed. A bearing restoration and refurbishment specification was prepared to improve bearing availability.

DEAL annual report.

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

Misra, Shashank

2017-11-01

The digital electronics at the atomic limit (DEAL) project seeks to leverage Sandia's atomic-precision fabrication capability to realize the theorized orders-of-magnitude improvement in operating voltage for tunnel field effect transistors (TFETs) compared to CMOS. Not only are low-power digital circuits a critical element of many national security systems (e.g. satellites), TFETs can perform circuit functions inaccessible to CMOS (e.g. polymorphism).

Exploring the Critical Dialogical Process: Psychological and Physical Spaces Creating Conditions Conducive to Multi-System Collective Action in Higher Education

ERIC Educational Resources Information Center

Pittman-Adkins, Pamela

2015-01-01

Purpose: The purpose of this study is to explore physical and psychological elements conducive to engaging educators from K-12 and higher education in meaningful exchanges that lead to collective action. Research Design: Through a qualitative case study of two higher education sites focused on advancing academically-based service learning…

Implementation of a self-controlling heater

NASA Technical Reports Server (NTRS)

Strange, M. G.

1973-01-01

Temperature control of radiation sensors, targets, and other critical components is a common requirement in modern scientific instruments. Conventional control systems use a heater and a temperature sensor mounted on the body to be controlled. For proportional control, the sensor provides feedback to circuitry which drives the heater with an amount of power proportional to the temperature error. It is impractical or undesirable to mount both a heater and a sensor on certain components such as ultra-small parts or thin filaments. In principle, a variable current through the element is used for heating, and the change in voltage drop due to the element's temperature coefficient is separated and used to monitor or control its own temperature. Since there are no thermal propagation delays between heater and sensor, such control systems are exceptionally stable.

Finite element solution of low bond number sloshing

NASA Technical Reports Server (NTRS)

Wohlen, R. L.; Park, A. C.; Warner, D. M.

1975-01-01

The dynamics of liquid propellant in a low Bond number environment which are critical to the design of spacecraft systems with respect to orbital propellant transfer and attitude control system were investigated. Digital computer programs were developed for the determination of liquid free surface equilibrium shape, lateral slosh natural vibration mode shapes, and frequencies for a liquid in a container of arbitrary axisymmetric shape with surface tension forces the same order of magnitude as acceleration forces. A finite volume element representation of the liquid was used for the vibration analysis. The liquid free surface equilibrium shapes were computed for several tanks at various contact angles and ullage volumes. A configuration was selected for vibration analysis and lateral slosh mode shapes and natural frequencies were obtained. Results are documented.

The Liquid Annular Reactor System (LARS) propulsion

NASA Technical Reports Server (NTRS)

Powell, James; Ludewig, Hans; Horn, Frederick; Lenard, Roger

1990-01-01

A concept for very high specific impulse (greater than 2000 seconds) direct nuclear propulsion is described. The concept, termed the liquid annular reactor system (LARS), uses liquid nuclear fuel elements to heat hydrogen propellant to very high temperatures (approximately 6000 K). Operating pressure is moderate (approximately 10 atm), with the result that the outlet hydrogen is virtually 100 percent dissociated to monatomic H. The molten fuel is contained in a solid container of its own material, which is rotated to stabilize the liquid layer by centripetal force. LARS reactor designs are described, together with neutronic and thermal-hydraulic analyses. Power levels are on the order of 200 megawatts. Typically, LARS designs use seven rotating fuel elements, are beryllium moderated, and have critical radii of approximately 100 cm (core L/D approximately equal to 1.5).

Experimental detailed power distribution in a fast spectrum thermionic reactor fuel element at the core/BeO reflector interface region

NASA Technical Reports Server (NTRS)

Klann, P. G.; Lantz, E.

1973-01-01

A zero-power critical assembly was designed, constructed, and operated for the prupose of conducting a series of benchmark experiments dealing with the physics characteristics of a UN-fueled, Li-7-cooled, Mo-reflected, drum-controlled compact fast reactor for use with a space-power conversion system. The critical assembly was modified to simulate a fast spectrum advanced thermionics reactor by: (1) using BeO as a reflector in place of some of the existing molybdenum, (2) substituting Nb-1Zr tubing for some of the existing Ta tubing, and (3) inserting four full-scale mockups of thermionic type fuel elements near the core and BeO reflector boundary. These mockups were surrounded with a buffer zone having the equivalent thermionic core composition. In addition to measuring the critical mass of this thermionic configuration, a detailed power distribution in one of the thermionic element stages in the mixed spectrum region was measured. A power peak to average ratio of two was observed for this fuel stage at the midplane of the core and adjacent to the reflector. Also, the power on the outer surface adjacent to the BeO was slightly more than a factor of two larger than the power on the inside surface of a 5.08 cm (2.0 in.) high annular fuel segment with a 2.52 cm (0.993 in. ) o.d. and a 1.86 cm (0.731 in.) i.d.

Design of Critical Components

NASA Technical Reports Server (NTRS)

Hendricks, Robert C.; Zaretsky, Erwin V.

2001-01-01

Critical component design is based on minimizing product failures that results in loss of life. Potential catastrophic failures are reduced to secondary failures where components removed for cause or operating time in the system. Issues of liability and cost of component removal become of paramount importance. Deterministic design with factors of safety and probabilistic design address but lack the essential characteristics for the design of critical components. In deterministic design and fabrication there are heuristic rules and safety factors developed over time for large sets of structural/material components. These factors did not come without cost. Many designs failed and many rules (codes) have standing committees to oversee their proper usage and enforcement. In probabilistic design, not only are failures a given, the failures are calculated; an element of risk is assumed based on empirical failure data for large classes of component operations. Failure of a class of components can be predicted, yet one can not predict when a specific component will fail. The analogy is to the life insurance industry where very careful statistics are book-kept on classes of individuals. For a specific class, life span can be predicted within statistical limits, yet life-span of a specific element of that class can not be predicted.

The Resilience Assessment Framework: a common indicator for land management?

NASA Astrophysics Data System (ADS)

Cowie, Annette; Metternicht, Graciela; O'Connell, Deborah

2015-04-01

At the Rio+20 conference in June 2013, the United Nations Convention to Combat Desertification (UNCCD), the Convention on Biological Diversity (CBD), and the United Nations Framework Convention on Climate Change (UNFCCC) reinforced their mutual interests in building linkages between biodiversity conservation, sustainable land management, and climate change mitigation and adaptation. The UNCCD sees building resilience of agro-ecosystems as a common interest that could strengthen linkages between the conventions and deliver synergies in progressing goals of each of the conventions. Furthermore, enhancing resilience of productive agro-ecosystems is fundamental to food security and sustainable development, and thus aligns with the Sustainable Development Goals (SDGs). The Global Environment Facility (GEF) shares the interest of the conventions in building resilience in agro-ecosystems. Indicators of resilience are required for monitoring progress in these endeavors, application of a common indicator between the UNCCD, UNFCCC and CBD as a measure of both land-based adaptation and ecosystem resilience, could strengthen links between the conventions and increase attention to the broad benefits of improved land management. Consequently, the Scientific and Technical Advisory Panel (STAP) to the GEF commissioned the Commonwealth Scientific and Industrial Research Organisation (CSIRO) to produce a report reviewing the conceptual basis for resilience, and proposing an indicator approach that could meet the needs of the Conventions and the GEF for an indicator of agro-ecosystem resilience and land-based adaption. The paper presents a synthesis of scientific understanding of resilience in agro-ecosystems, reviews indicators that have been proposed, and, having concluded that none of the extant indicator approaches adequately assesses resilience of agro-ecosystems, proposes a new approach to the assessment of resilience. Recognizing that no single indicator of resilience is applicable to all agro-ecosystems, and that involvement of stakeholders is critical to discerning the critical variables to be assessed, the proposed framework uses an iterative participatory approach to characterise the system, considering also interactions across and within scales; identify the controlling variables, and assess proximity to thresholds, and adaptive capacity. The framework consists of four elements: Element A: System description; Element B Assessing the system; Element C Adaptive governance and management; Element D Participatory process. Element D is intended as a cross-cutting element, applying across Elements A to C, although Elements A and B can be applied as a desktop activity in a preliminary assessment. The results of the assessment are synthesised in "Resilience action indicators", that summarise the state of the system with respect to the need to adapt or transform. The presentation will summarise the framework and the responses of expert reviewers who identified strengths of the approach, and challenges for implementation, particularly at program and national scales. The presentation will emphasise the conceptual basis for the approach, and the role of scientists in testing, refining and operationalizing the approach.

Stability analysis and backward whirl investigation of cracked rotors with time-varying stiffness

NASA Astrophysics Data System (ADS)

AL-Shudeifat, Mohammad A.

2015-07-01

The dynamic stability of dynamical systems with time-periodic stiffness is addressed here. Cracked rotor systems with time-periodic stiffness are well-known examples of such systems. Time-varying area moments of inertia at the cracked element cross-section of a cracked rotor have been used to formulate the time-periodic finite element stiffness matrix. The semi-infinite coefficient matrix obtained by applying the harmonic balance (HB) solution to the finite element (FE) equations of motion is employed here to study the dynamic stability of the system. Consequently, the sign of the determinant of a scaled version of a sub-matrix of this semi-infinite coefficient matrix at a finite number of harmonics in the HB solution is found to be sufficient for identifying the major unstable zones of the system in the parameter plane. Specifically, it is found that the negative determinant always corresponds to unstable zones in all of the systems considered. This approach is applied to a parametrically excited Mathieu's equation, a two degree-of-freedom linear time-periodic dynamical system, a cracked Jeffcott rotor and a finite element model of the cracked rotor system. Compared to the corresponding results obtained by Floquet's theory, the sign of the determinant of the scaled sub-matrix is found to be an efficient tool for identifying the major unstable zones of the linear time-periodic parametrically excited systems, especially large-scale FE systems. Moreover, it is found that the unstable zones for a FE cracked rotor with an open transverse crack model only appear at the backward whirl. The theoretical and experimental results have been found to agree well for verifying that the open crack model excites the backward whirl amplitudes at the critical backward whirling rotational speeds.

Microscale Convective Heat Transfer for Thermal Management of Compact Systems

DTIC Science & Technology

2012-03-12

pages 641–645, 1997. [9] S.V. Garimella and C.B. Sobhan. Transport in microchannels -a critical review. Annual Review of Heat Transfer , 13, 2003. [10] A... heat transfer for thermal management of compact systems Sb. GRANT NUMBER F A9550-08-l-0057 Sc. PROGRAM ELEMENT NUMBER 61102F 6. AUTHOR(S) Sd...improve the performance of many components. The e ects of digitized heat transfer using electrowetting on a dielectric were investigated in this paper

Incineration of nuclear waste by accelerator

NASA Astrophysics Data System (ADS)

Martino, J.; Fioni, G.; Leray, S.

1998-10-01

An important international effort is devoted to find a suitable solution to incinerate radioactive nuclear waste issued from conventional power plants and from nuclear disarmament. Practically all innovative projects consist of a sub critical system driven by an external neutron source obtained by spallation induced by a high intensity proton accelerator irradiating a heavy target. New nuclear data measurements are necessary for the realization of these systems, in particular a good knowledge of the spallation process and of the neutron cross sections for transuranic elements are essential.

Ending on a positive: Examining the role of safety leadership decisions, behaviours and actions in a safety critical situation.

PubMed

Donovan, Sarah-Louise; Salmon, Paul M; Horberry, Timothy; Lenné, Michael G

2018-01-01

Safety leadership is an important factor in supporting safe performance in the workplace. The present case study examined the role of safety leadership during the Bingham Canyon Mine high-wall failure, a significant mining incident in which no fatalities or injuries were incurred. The Critical Decision Method (CDM) was used in conjunction with a self-reporting approach to examine safety leadership in terms of decisions, behaviours and actions that contributed to the incidents' safe outcome. Mapping the analysis onto Rasmussen's Risk Management Framework (Rasmussen, 1997), the findings demonstrate clear links between safety leadership decisions, and emergent behaviours and actions across the work system. Communication and engagement based decisions featured most prominently, and were linked to different leadership practices across the work system. Further, a core sub-set of CDM decision elements were linked to the open flow and exchange of information across the work system, which was critical to supporting the safe outcome. The findings provide practical implications for the development of safety leadership capability to support safety within the mining industry. Copyright © 2017 Elsevier Ltd. All rights reserved.

Experimental Partitioning of Chalcophile Elements between Mantle Silicate Minerals and Basaltic Melt at High Pressures and Temperatures - Implications for Sulfur Geochemistry of Mantle and Crust

NASA Astrophysics Data System (ADS)

Dasgupta, R.; Jego, S.; Ding, S.; Li, Y.; Lee, C. T.

2015-12-01

The behavior of chalcophile elements during mantle melting, melt extraction, and basalt differentiation is critical for formation of ore deposits and geochemical model and evolution of crust-mantle system. While chalcophile elements are strongly partitioned into sulfides, their behavior with different extent of melting, in particular, in the absence of sulfides, can only be modeled with complete knowledge of the partitioning behavior of these elements between dominant mantle minerals and basaltic melt with or without dissolved sulfide (S2-). However, experimental data on mineral-melt partitioning are lacking for many chalcophile elements. Crystallization experiments were conducted at 3 GPa and 1450-1600 °C using a piston cylinder and synthetic silicate melt compositions similar to low-degree partial melt of peridotite. Starting silicate mixes doped with 100-300 ppm of each of various chalcophile elements were loaded into Pt/graphite double capsules. To test the effect of dissolved sulfur in silicate melt on mineral-melt partitioning of chalcophile elements, experiments were conducted on both sulfur-free and sulfur-bearing (1100-1400 ppm S in melt) systems. Experimental phases were analyzed by EPMA (for major elements and S) and LA-ICP-MS (for trace elements). All experiments produced an assemblage of cpx + melt ± garnet ± olivine ± spinel and yielded new partition coefficients (D) for Sn, Zn, Mo, Sb, Bi, Pb, and Se for cpx/melt, olivine/melt, and garnet/melt pairs. Derived Ds (mineral/basalt) reveal little effect of S2- in the melt on mineral-melt partition coefficients of the measured chalcophile elements, with Ds for Zn, Mo, Bi, Pb decreasing by less than a factor of 2 from S-free to S-bearing melt systems or remaining similar, within error, between S-free and S-bearing melt systems. By combining our data with existing partitioning data between sulfide phases and silicate melt we model the fractionation of these elements during mantle melting and basalt crystallization. The model results are compared with the chalcophile element abundance in oceanic basalts. We will discuss the implications of our new partitioning data and model results on sulfur and chalcophile element geochemistry of mantle source regions of ocean floor basalts and the fate of sulfides during mantle melting.

Using a Critical Service-Learning Approach to Facilitate Civic Identity Development

ERIC Educational Resources Information Center

Mitchell, Tania D.

2015-01-01

This article highlights elements of civic engagement programs that have the rich potential to facilitate civic identity development. Focusing on research with alumni, the study examines 3 civic engagement programs, the approaches of which are guided by critical service-learning. It explores elements of the experiences that alumni name as…

Sequences spanning the leader-repeat junction mediate CRISPR adaptation to phage in Streptococcus thermophilus

PubMed Central

Wei, Yunzhou; Chesne, Megan T.; Terns, Rebecca M.; Terns, Michael P.

2015-01-01

CRISPR-Cas systems are RNA-based immune systems that protect prokaryotes from invaders such as phages and plasmids. In adaptation, the initial phase of the immune response, short foreign DNA fragments are captured and integrated into host CRISPR loci to provide heritable defense against encountered foreign nucleic acids. Each CRISPR contains a ∼100–500 bp leader element that typically includes a transcription promoter, followed by an array of captured ∼35 bp sequences (spacers) sandwiched between copies of an identical ∼35 bp direct repeat sequence. New spacers are added immediately downstream of the leader. Here, we have analyzed adaptation to phage infection in Streptococcus thermophilus at the CRISPR1 locus to identify cis-acting elements essential for the process. We show that the leader and a single repeat of the CRISPR locus are sufficient for adaptation in this system. Moreover, we identified a leader sequence element capable of stimulating adaptation at a dormant repeat. We found that sequences within 10 bp of the site of integration, in both the leader and repeat of the CRISPR, are required for the process. Our results indicate that information at the CRISPR leader-repeat junction is critical for adaptation in this Type II-A system and likely other CRISPR-Cas systems. PMID:25589547

Postmarketing Safety Study Tool: A Web Based, Dynamic, and Interoperable System for Postmarketing Drug Surveillance Studies

PubMed Central

Sinaci, A. Anil; Laleci Erturkmen, Gokce B.; Gonul, Suat; Yuksel, Mustafa; Invernizzi, Paolo; Thakrar, Bharat; Pacaci, Anil; Cinar, H. Alper; Cicekli, Nihan Kesim

2015-01-01

Postmarketing drug surveillance is a crucial aspect of the clinical research activities in pharmacovigilance and pharmacoepidemiology. Successful utilization of available Electronic Health Record (EHR) data can complement and strengthen postmarketing safety studies. In terms of the secondary use of EHRs, access and analysis of patient data across different domains are a critical factor; we address this data interoperability problem between EHR systems and clinical research systems in this paper. We demonstrate that this problem can be solved in an upper level with the use of common data elements in a standardized fashion so that clinical researchers can work with different EHR systems independently of the underlying information model. Postmarketing Safety Study Tool lets the clinical researchers extract data from different EHR systems by designing data collection set schemas through common data elements. The tool interacts with a semantic metadata registry through IHE data element exchange profile. Postmarketing Safety Study Tool and its supporting components have been implemented and deployed on the central data warehouse of the Lombardy region, Italy, which contains anonymized records of about 16 million patients with over 10-year longitudinal data on average. Clinical researchers in Roche validate the tool with real life use cases. PMID:26543873

The physical vulnerability of elements at risk: a methodology based on fluid and classical mechanics

NASA Astrophysics Data System (ADS)

Mazzorana, B.; Fuchs, S.; Levaggi, L.

2012-04-01

The impacts of the flood events occurred in autumn 2011 in the Italian regions Liguria and Tuscany revived the engagement of the public decision makers to enhance in synergy flood control and land use planning. In this context, the design of efficient flood risk mitigation strategies and their subsequent implementation critically relies on a careful vulnerability analysis of both, the immobile and mobile elements at risk potentially exposed to flood hazards. Based on fluid and classical mechanics notions we developed computation schemes enabling for a dynamic vulnerability and risk analysis facing a broad typological variety of elements at risk. The methodological skeleton consists of (1) hydrodynamic computation of the time-varying flood intensities resulting for each element at risk in a succession of loading configurations; (2) modelling the mechanical response of the impacted elements through static, elasto-static and dynamic analyses; (3) characterising the mechanical response through proper structural damage variables and (4) economic valuation of the expected losses as a function of the quantified damage variables. From a computational perspective we coupled the description of the hydrodynamic flow behaviour and the induced structural modifications of the elements at risk exposed. Valuation methods, suitable to support a correct mapping from the value domains of the physical damage variables to the economic loss values are discussed. In such a way we target to complement from a methodological perspective the existing, mainly empirical, vulnerability and risk assessment approaches to refine the conceptual framework of the cost-benefit analysis. Moreover, we aim to support the design of effective flood risk mitigation strategies by diminishing the main criticalities within the systems prone to flood risk.

Whirl Motion of a Seal Test Rig with Squeeze-Film Dampers

NASA Technical Reports Server (NTRS)

Proctor, Margaret P.; Gunter, Edgar J.

2007-01-01

This paper presents the experimental behavior and dynamic analysis of a high speed test rig with rolling element bearings mounted in squeeze film oil damper bearings. The test rotor is a double overhung configuration with rolling element ball bearings mounted in uncentered squeeze-film oil dampers. The damper design is similar to that employed with various high-speed aircraft HP gas turbines. The dynamic performance of the test rig with the originally installed dampers with an effective damper length of length 0.23-inch was unacceptable. The design speed of 40,000 RPM could not be safely achieved as nonsynchronous whirling at the overhung seal test disk and high amplitude critical speed response at the drive spline section occurred at 32,000 RPM. In addition to the self excited stability and critical speed problems, it was later seen from FFT data analysis, that a region of supersynchronous dead band whirling occurs between 10,000 to 15,000 RPM which can lead to bearing distress and wear. The system was analyzed using both linear and nonlinear techniques. The extended length damper design resulting from the analysis eliminated the rotor subsynchronous whirling, high amplitude critical speed, and the dead band whirling region allowing the system to achieve a speed of 45,000 RPM. However, nonlinear analysis shows that damper lockup could occur with high rotor unbalance at 33,000 RPM, even with the extended squeeze-film dampers. The control of damper lockup will be addressed in a future paper.

Critical Elements in Produced Fluids from Nevada and Utah

DOE Data Explorer

Simmons, Stuart

2017-07-27

Critical elements and related analytical data for produced fluids from geothermal fields in Nevada and Utah, Sevier thermal belt hot springs, Utah, and Uinta basin oil-gas wells, Utah are reported. Analytical results include pH, major species, trace elements, transition metals, other metals, metalloids and REEs. Gas samples were collected and analyzed from Beowawe, Dixie Valley, Roosevelt Hot Springs, and Thermo. Helium gases and helium isotopes were analyzed on samples collected at Patua, San Emido and two wells in the Uinta basin.

Long Duration Exposure Facility (LDEF) optical systems SIG summary and database

NASA Astrophysics Data System (ADS)

Bohnhoff-Hlavacek, Gail

1992-09-01

The main objectives of the Long Duration Exposure Facility (LDEF) Optical Systems Special Investigative Group (SIG) Discipline are to develop a database of experimental findings on LDEF optical systems and elements hardware, and provide an optical system overview. Unlike the electrical and mechanical disciplines, the optics effort relies primarily on the testing of hardware at the various principal investigator's laboratories, since minimal testing of optical hardware was done at Boeing. This is because all space-exposed optics hardware are part of other individual experiments. At this time, all optical systems and elements testing by experiment investigator teams is not complete, and in some cases has hardly begun. Most experiment results to date, document observations and measurements that 'show what happened'. Still to come from many principal investigators is a critical analysis to explain 'why it happened' and future design implications. The original optical system related concerns and the lessons learned at a preliminary stage in the Optical Systems Investigations are summarized. The design of the Optical Experiments Database and how to acquire and use the database to review the LDEF results are described.

Long Duration Exposure Facility (LDEF) optical systems SIG summary and database

NASA Technical Reports Server (NTRS)

Bohnhoff-Hlavacek, Gail

1992-01-01

The main objectives of the Long Duration Exposure Facility (LDEF) Optical Systems Special Investigative Group (SIG) Discipline are to develop a database of experimental findings on LDEF optical systems and elements hardware, and provide an optical system overview. Unlike the electrical and mechanical disciplines, the optics effort relies primarily on the testing of hardware at the various principal investigator's laboratories, since minimal testing of optical hardware was done at Boeing. This is because all space-exposed optics hardware are part of other individual experiments. At this time, all optical systems and elements testing by experiment investigator teams is not complete, and in some cases has hardly begun. Most experiment results to date, document observations and measurements that 'show what happened'. Still to come from many principal investigators is a critical analysis to explain 'why it happened' and future design implications. The original optical system related concerns and the lessons learned at a preliminary stage in the Optical Systems Investigations are summarized. The design of the Optical Experiments Database and how to acquire and use the database to review the LDEF results are described.

High temperature properties of non-critical Fe-Al alloys doped by non critical or “slightly–critical” elements

NASA Astrophysics Data System (ADS)

Vodičková, Věra; Hanus, Pavel; Vlasák, Tomáš; Švec, Martin

2018-03-01

Iron aluminides were developed as an alternative to stainless steels after World War II. The main intended impact was to save strategic elements (chromium or nickel). The result of these investigations was development of registered alloys as Pyroferal (Czechoslovak Republic), Thugal (Soviet Union) or Thermagal (France). The investigation of these type alloys continued in the nineties thanks to technological progress. In this time iron aluminides seems to be promising material with very good corrosive and environment resistivity. The mechanical properties of binary iron aluminides (Fe-Al) are average at higher temperatures but strengthening effect of alloying elements is significant. The aim of the article is to show influence of non-critical additives (such as C, Ti, Zr) and also “slightly critical” elements as e.g. Ce, Nb on high temperature creep properties of alloys.

Ground test facility for SEI nuclear rocket engines

NASA Astrophysics Data System (ADS)

Harmon, Charles D.; Ottinger, Cathy A.; Sanchez, Lawrence C.; Shipers, Larry R.

1992-07-01

Nuclear (fission) thermal propulsion has been identified as a critical technology for a manned mission to Mars by the year 2019. Facilities are required that will support ground tests to qualify the nuclear rocket engine design, which must support a realistic thermal and neutronic environment in which the fuel elements will operate at a fraction of the power for a flight weight reactor/engine. This paper describes the design of a fuel element ground test facility, with a strong emphasis on safety and economy. The details of major structures and support systems of the facility are discussed, and a design diagram of the test facility structures is presented.

Simulating flaring events in complex active regions driven by observed magnetograms

NASA Astrophysics Data System (ADS)

Dimitropoulou, M.; Isliker, H.; Vlahos, L.; Georgoulis, M. K.

2011-05-01

Context. We interpret solar flares as events originating in active regions that have reached the self organized critical state, by using a refined cellular automaton model with initial conditions derived from observations. Aims: We investigate whether the system, with its imposed physical elements, reaches a self organized critical state and whether well-known statistical properties of flares, such as scaling laws observed in the distribution functions of characteristic parameters, are reproduced after this state has been reached. Methods: To investigate whether the distribution functions of total energy, peak energy and event duration follow the expected scaling laws, we first applied a nonlinear force-free extrapolation that reconstructs the three-dimensional magnetic fields from two-dimensional vector magnetograms. We then locate magnetic discontinuities exceeding a threshold in the Laplacian of the magnetic field. These discontinuities are relaxed in local diffusion events, implemented in the form of cellular automaton evolution rules. Subsequent loading and relaxation steps lead the system to self organized criticality, after which the statistical properties of the simulated events are examined. Physical requirements, such as the divergence-free condition for the magnetic field vector, are approximately imposed on all elements of the model. Results: Our results show that self organized criticality is indeed reached when applying specific loading and relaxation rules. Power-law indices obtained from the distribution functions of the modeled flaring events are in good agreement with observations. Single power laws (peak and total flare energy) are obtained, as are power laws with exponential cutoff and double power laws (flare duration). The results are also compared with observational X-ray data from the GOES satellite for our active-region sample. Conclusions: We conclude that well-known statistical properties of flares are reproduced after the system has reached self organized criticality. A significant enhancement of our refined cellular automaton model is that it commences the simulation from observed vector magnetograms, thus facilitating energy calculation in physical units. The model described in this study remains consistent with fundamental physical requirements, and imposes physically meaningful driving and redistribution rules.

Critical roles of orthopaedic surgeon leadership in healthcare systems to improve orthopaedic surgical patient safety.

PubMed

Kuo, Calvin C; Robb, William J

2013-06-01

The prevention of medical and surgical harm remains an important public health problem despite increased awareness and implementation of safety programs. Successful introduction and maintenance of surgical safety programs require both surgeon leadership and collaborative surgeon-hospital alignment. Documentation of success of such surgical safety programs in orthopaedic practice is limited. We describe the scope of orthopaedic surgical patient safety issues, define critical elements of orthopaedic surgical safety, and outline leadership roles for orthopaedic surgeons needed to establish and sustain a culture of safety in contemporary healthcare systems. We identified the most common causes of preventable surgical harm based on adverse and sentinel surgical events reported to The Joint Commission. A comprehensive literature review through a MEDLINE(®) database search (January 1982 through April 2012) to identify pertinent orthopaedic surgical safety articles found 14 articles. Where gaps in orthopaedic literature were identified, the review was supplemented by 22 nonorthopaedic surgical references. Our final review included 36 articles. Six important surgical safety program elements needed to eliminate preventable surgical harm were identified: (1) effective surgical team communication, (2) proper informed consent, (3) implementation and regular use of surgical checklists, (4) proper surgical site/procedure identification, (5) reduction of surgical team distractions, and (6) routine surgical data collection and analysis to improve the safety and quality of surgical patient care. Successful surgical safety programs require a culture of safety supported by all six key surgical safety program elements, active surgeon champions, and collaborative hospital and/or administrative support designed to enhance surgical safety and improve surgical patient outcomes. Further research measuring improvements from such surgical safety systems in orthopaedic care is needed.

Precision machining of optical surfaces with subaperture correction technologies MRF and IBF

NASA Astrophysics Data System (ADS)

Schmelzer, Olaf; Feldkamp, Roman

2015-10-01

Precision optical elements are used in a wide range of technical instrumentations. Many optical systems e.g. semiconductor inspection modules, laser heads for laser material processing or high end movie cameras, contain precision optics even aspherical or freeform surfaces. Critical parameters for such systems are wavefront error, image field curvature or scattered light. Following these demands the lens parameters are also critical concerning power and RMSi of the surface form error and micro roughness. How can we reach these requirements? The emphasis of this discussion is set on the application of subaperture correction technologies in the fabrication of high-end aspheres and free-forms. The presentation focuses on the technology chain necessary for the production of high-precision aspherical optical components and the characterization of the applied subaperture finishing tools MRF (magneto-rheological finishing) and IBF (ion beam figuring). These technologies open up the possibility of improving the performance of optical systems.

Exploration Life Support Critical Questions for Future Human Space Missions

NASA Technical Reports Server (NTRS)

Ewert, Michael K.; Barta, Daniel J.; McQuillan, Jeff

2009-01-01

Exploration Life Support (ELS) is a project under NASA s Exploration Technology Development Program. The ELS Project plans, coordinates and implements the development of advanced life support technologies for human exploration missions in space. Recent work has focused on closed loop atmosphere and water systems for a lunar outpost, including habitats and pressurized rovers. But, what are the critical questions facing life support system developers for these and other future human missions? This paper explores those questions and discusses how progress in the development of ELS technologies can help answer them. The ELS Project includes Atmosphere Revitalization Systems (ARS), Water Recovery Systems (WRS), Waste Management Systems (WMS), Habitation Engineering, Systems Integration, Modeling and Analysis (SIMA), and Validation and Testing, which includes the sub-elements Flight Experiments and Integrated Testing. Systems engineering analysis by ELS seeks to optimize the overall mission architecture by considering all the internal and external interfaces of the life support system and the potential for reduction or reuse of commodities. In particular, various sources and sinks of water and oxygen are considered along with the implications on loop closure and the resulting launch mass requirements.

System-level planning, coordination, and communication: care of the critically ill and injured during pandemics and disasters: CHEST consensus statement.

PubMed

Dichter, Jeffrey R; Kanter, Robert K; Dries, David; Luyckx, Valerie; Lim, Matthew L; Wilgis, John; Anderson, Michael R; Sarani, Babak; Hupert, Nathaniel; Mutter, Ryan; Devereaux, Asha V; Christian, Michael D; Kissoon, Niranjan

2014-10-01

System-level planning involves uniting hospitals and health systems, local/regional government agencies, emergency medical services, and other health-care entities involved in coordinating and enabling care in a major disaster. We reviewed the literature and sought expert opinions concerning system-level planning and engagement for mass critical care due to disasters or pandemics and offer suggestions for system-planning, coordination, communication, and response. The suggestions in this chapter are important for all of those involved in a pandemic or disaster with multiple critically ill or injured patients, including front-line clinicians, hospital administrators, and public health or government officials. The American College of Chest Physicians (CHEST) consensus statement development process was followed in developing suggestions. Task Force members met in person to develop nine key questions believed to be most relevant for system-planning, coordination, and communication. A systematic literature review was then performed for relevant articles and documents, reports, and other publications reported since 1993. No studies of sufficient quality were identified upon which to make evidence-based recommendations. Therefore, the panel developed expert opinion-based suggestions using a modified Delphi process. Suggestions were developed and grouped according to the following thematic elements: (1) national government support of health-care coalitions/regional health authorities (HC/RHAs), (2) teamwork within HC/RHAs, (3) system-level communication, (4) system-level surge capacity and capability, (5) pediatric patients and special populations, (6) HC/RHAs and networks, (7) models of advanced regional care systems, and (8) the use of simulation for preparedness and planning. System-level planning is essential to provide care for large numbers of critically ill patients because of disaster or pandemic. It also entails a departure from the routine, independent system and involves all levels from health-care institutions to regional health authorities. National government support is critical, as are robust communication systems and advanced planning supported by realistic exercises.

Complexity and Productivity Differentiation Models of Metallogenic Indicator Elements in Rocks and Supergene Media Around Daijiazhuang Pb-Zn Deposit in Dangchang County, Gansu Province

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

He, Jin-zhong, E-mail: viewsino@163.com; Yao, Shu-zhen; Zhang, Zhong-ping

2013-03-15

With the help of complexity indices, we quantitatively studied multifractals, frequency distributions, and linear and nonlinear characteristics of geochemical data for exploration of the Daijiazhuang Pb-Zn deposit. Furthermore, we derived productivity differentiation models of elements from thermodynamics and self-organized criticality of metallogenic systems. With respect to frequency distributions and multifractals, only Zn in rocks and most elements except Sb in secondary media, which had been derived mainly from weathering and alluviation, exhibit nonlinear distributions. The relations of productivity to concentrations of metallogenic elements and paragenic elements in rocks and those of elements strongly leached in secondary media can be seenmore » as linear addition of exponential functions with a characteristic weak chaos. The relations of associated elements such as Mo, Sb, and Hg in rocks and other elements in secondary media can be expressed as an exponential function, and the relations of one-phase self-organized geological or metallogenic processes can be represented by a power function, each representing secondary chaos or strong chaos. For secondary media, exploration data of most elements should be processed using nonlinear mathematical methods or should be transformed to linear distributions before processing using linear mathematical methods.« less

ON CRITICAL MASS ANALYSIS OF JRR-2

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

None

1961-01-01

The critica mass of the JRR-2 was found to be 15 fuel elements, instead of 8 as expected, when the reactor reached criticaity. The critica mass was analyzed by AMF and JAERI a few years ago, but afterwards some modifications have been made of the stucture for the reinforcement, for example, during the construction. The critical mass is recalculated perfectly and the difference bctween 15 and S fuel elements is discussed. The deviation of the critical mass is mainly caused by the effects of control rods, fuel elcments, grid-plate, etc., in the reflector; only heavy water or light water wasmore » conaidered as the reflector in the previous calculation. A simple method is used to calculate the critical mass. The effective multiplication factor for the core with 15 fuel elements is obtained about 2% higher than the experimental value. This difference is also discussed in detail. (auth)« less

Medical education in cyberspace: critical considerations in the health system

PubMed Central

YAZDANI, SHAHRAM; KHOSHGOFTAR, ZOHREH; AHMADY, SOLEIMAN; RASTEGARPOUR, HASSAN; FOROUTAN, SEYED ABBAS

2017-01-01

Introduction: Over the past few decades, two revolutionary approaches have emerged as a new form of medical education: Electronic Medical Education and Web-based Medical Education. A number of well-known medical institutions, such as Harvard and Johns Hopkins used a wide range of cyberspace capabilities to increase their competitiveness. Researchers have expressed that cyberspace will change health system’s main objective of training physicians and medical education. We conducted this study to identify the health system critical considerations on core issues, involving the development of medical education on cyberspace. Methods: In order to conduct this study, we observed the steps of a critical literature review, combined with the ‘Four-phase method’ adopted by Carnwell and Daly. We focused on particular literature on health and cyber system functions; it was associated with systemic approach. Results: We developed a six-level taxonomy, Cyber level, Governance level, Ministerial level, Organizational level, Program level and Performance level, as a key solution that can be applied for the success of medical education on cyberspace. The results were summarized and appraised in more details. Conclusion: Medical education on cyberspace is a complex interdisciplinary system. It is important that all aspects of the health systems be involved as integral to the development of cyber based medical education; without this convergence, we will be confused by the decisions made by others within the system. Health system should also communicate with those external sectors that are critical to achieving better learning on cyberspace. Integrated planning, governance and management of medical education in cyberspace are pivotal elements for the promotion. PMID:28124017

CIS: where are we going and what should we demand from industry?

PubMed

Frassica, Joseph J

2004-12-01

Clinical information systems designed for use in the critical care setting have been available for many years. Yet, despite significant evidence that these systems contribute to patient safety and efficiency of care, they have not achieved widespread use. This paper examines some of the factors responsible for the slow growth in use of clinical information systems in the intensive care unit. We further examine the elements that will be necessary to support widespread adoption of future clinical information systems. We give an outline of functionalities, processes, and standards that users will demand from industry as they develop the information systems of the future.

Criticality of iron and its principal alloying elements.

PubMed

Nuss, Philip; Harper, E M; Nassar, N T; Reck, Barbara K; Graedel, T E

2014-04-01

Because modern technology depends on reliable supplies of a wide variety of materials and because of increasing concern about those supplies, a comprehensive methodology was created to quantify the degree of criticality of the metals of the periodic table. In this paper, we apply this methodology to iron and several of its main alloying elements (i.e., vanadium, chromium, manganese, and niobium). These elements represent the basic metals of any industrial society and are vital for national security and economic well-being. Assessments relating to the dimensions of criticality - supply risk, vulnerability to supply restriction, and environmental implications - for 2008 are made on the global level and for the United States. Evaluations of each of the multiple indicators are presented, with aggregate results plotted in "criticality space", together with Monte Carlo simulation-derived "uncertainty cloud" estimates. Iron has the lowest supply risk, primarily because of its widespread geological occurrence. Vanadium displays the highest cradle-to-gate environmental implications, followed by niobium, chromium, manganese, and iron. Chromium and manganese, both essential in steel making, display the highest vulnerability to supply restriction, largely because substitution or substitution at equal performance is not possible for all end-uses. From a comprehensive perspective, we regard the overall criticality as low for iron and modest for the alloying elements we evaluated.

Building clinical data groups for electronic medical record in China.

PubMed

Tu, Haibo; Yu, Yingtao; Yang, Peng; Tang, Xuejun; Hu, Jianping; Rao, Keqin; Pan, Feng; Xu, Yongyong; Liu, Danhong

2012-04-01

This article aims at building clinical data groups for Electronic Medical Records (EMR) in China. These data groups can be reused as basic information units in building the medical sheets of Electronic Medical Record Systems (EMRS) and serve as part of its implementation guideline. The results were based on medical sheets, the forms that are used in hospitals, which were collected from hospitals. To categorize the information in these sheets into data groups, we adopted the Health Level 7 Clinical Document Architecture Release 2 Model (HL7 CDA R2 Model). The regulations and legal documents concerning health informatics and related standards in China were implemented. A set of 75 data groups with 452 data elements was created. These data elements were atomic items that comprised the data groups. Medical sheet items contained clinical records information and could be described by standard data elements that exist in current health document protocols. These data groups match different units of the CDA model. Twelve data groups with 87 standardized data elements described EMR headers, and 63 data groups with 405 standardized data elements constituted the body. The later 63 data groups in fact formed the sections of the model. The data groups had two levels. Those at the first level contained both the second level data groups and the standardized data elements. The data groups were basically reusable information units that served as guidelines for building EMRS and that were used to rebuild a medical sheet and serve as templates for the clinical records. As a pilot study of health information standards in China, the development of EMR data groups combined international standards with Chinese national regulations and standards, and this was the most critical part of the research. The original medical sheets from hospitals contain first hand medical information, and some of their items reveal the data types characteristic of the Chinese socialist national health system. It is possible and critical to localize and stabilize the adopted international health standards through abstracting and categorizing those items for future sharing and for the implementation of EMRS in China.

Biomimetric sentinel reef structures for optical sensing and communications

NASA Astrophysics Data System (ADS)

Fries, David; Hutcheson, Tim; Josef, Noam; Millie, David; Tate, Connor

2017-05-01

Traditional artificial reef structures are designed with uniform cellular architectures and topologies and do not mimic natural reef forms. Strings and ropes are a proven, common fisheries and mariculture construction element throughout the world and using them as artificial reef scaffolding can enable a diversity of ocean sensing, communications systems including the goal of sentinel reefs. The architecture and packaging of electronics is key to enabling such structures and systems. The distributed sensor reef concept leads toward a demonstrable science-engineering-informed framework for 3D smart habitat designs critical to stock fish development and coastal monitoring and protection. These `nature-inspired' reef infrastructures, can enable novel instrumented `reef observatories' capable of collecting real-time ecosystem data. Embedding lighting and electronic elements into artificial reef systems are the first systems conceptualized. This approach of bringing spatial light to the underwater world for optical sensing, communication and even a new breed of underwater robotic vehicle is an interdisciplinary research activity which integrates principles of electronic packaging, and ocean technology with art/design.

PL-3, PHASE I, TASK 3, RESEARCH AND DEVELOPMENT REPORT

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

Humphries, G. E.

1962-03-12

Results of researeh and development tasks are presented along with recommendations for future development work Work (s reported ofn the areas of plant assembly and relocation, housings and footings, waste heat dissipation, instrumentation, refueling systems, waste disposal, shiceding, core nuclear thermal and hydraulic studies, gaseous waste processing, and critical experiments on a 5 x 5 array of Type 3 fuel elements. (auth)

Zirconium as a Structural Material for Naval Systems

DTIC Science & Technology

1985-03-29

case with the technologically critical chemical elements chromium and cobalt, for example, from a military perspective. The case, therefore, for...By adding small amounts of tin, iron, nickel, and chromium , the impurities were effectively bound or coalesced within the metal and the corrosion...and nitrogen from the atmosphere, embrittling the weld. The techniques used for zirconium welding are gas tungsten arc welding ( GTAW ), tungsten inert

[Risk management in anesthesia and critical care medicine].

PubMed

Eisold, C; Heller, A R

2017-03-01

Throughout its history, anesthesia and critical care medicine has experienced vast improvements to increase patient safety. Consequently, anesthesia has never been performed on such a high level as it is being performed today. As a result, we do not always fully perceive the risks involved in our daily activity. A survey performed in Swiss hospitals identified a total of 169 hot spots which endanger patient safety. It turned out that there is a complex variety of possible errors that can only be tackled through consistent implementation of a safety culture. The key elements to reduce complications are continuing staff education, algorithms and standard operating procedures (SOP), working according to the principles of crisis resource management (CRM) and last but not least the continuous work-up of mistakes identified by critical incident reporting systems.

Antioxidant Vitamins and Trace Elements in Critical Illness.

PubMed

Koekkoek, W A C Kristine; van Zanten, Arthur R H

2016-08-01

This comprehensive narrative review summarizes relevant antioxidant mechanisms, the antioxidant status, and effects of supplementation in critically ill patients for the most studied antioxidant vitamins A, C, and E and the enzyme cofactor trace elements selenium and zinc. Over the past 15 years, oxidative stress-mediated cell damage has been recognized to be fundamental to the pathophysiology of various critical illnesses such as acute respiratory distress syndrome, ischemia-reperfusion injury, and multiorgan dysfunction in sepsis. Related to these conditions, low plasma levels of antioxidant enzymes, vitamins, and trace elements have been frequently reported, and thus supplementation seems logical. However, low antioxidant plasma levels per se may not indicate low total body stores as critical illness may induce redistribution of antioxidants. Furthermore, low antioxidant levels may even be beneficial as pro-oxidants are essential in bacterial killing. The reviewed studies in critically ill patients show conflicting results. This may be due to different patient populations, study designs, timing, dosing regimens, and duration of the intervention and outcome measures evaluated. Therefore, at present, it remains unclear whether supplementation of antioxidant micronutrients has any clinical benefit in critically ill patients as some studies show clear benefits, whereas others demonstrate neutral outcomes and even harm. Combination therapy of antioxidants seems logical as they work in synergy and function as elements of the human antioxidant network. Further research should focus on defining the normal antioxidant status for critically ill patients and to study optimal supplement combinations either by nutrition enrichment or by enteral or parenteral pharmacological interventions. © 2016 American Society for Parenteral and Enteral Nutrition.

Overview of the Development and Mission Application of the Advanced Electric Propulsion System (AEPS)

NASA Technical Reports Server (NTRS)

Herman, Daniel A.; Tofil, Todd; Santiago, Walter; Kamhawi, Hani; Polk, James E.; Snyder, John Steven; Hofer, Richard R.; Picha, Frank; Jackson, Jerry; Allen, May

2017-01-01

NASA remains committed to the development and demonstration of a high-power solar electric propulsion capability for the Agency. NASA is continuing to develop the 14 kilowatt Advanced Electric Propulsion System (AEPS), which has recently completed an Early Integrated System Test and System Preliminary Design Review. NASA continues to pursue Solar Electric Propulsion (SEP) Technology Demonstration Mission partners and mature high-power SEP mission concepts. The recent announcement of the development of a Power and Propulsion Element (PPE) as the first element of an evolvable human architecture to Mars has replaced the Asteroid Redirect Robotic Mission as the most probable first application of the AEPS Hall thruster system. This high-power SEP capability, or an extensible derivative of it, has been identified as a critical part of an affordable, beyond-low-Earth-orbit, manned-exploration architecture. This paper presents the status of the combined NASA and Aerojet AEPS development activities and updated mission concept for implementation of the AEPS hardware as part of the ion propulsion system for a PPE.

Overview of the Development and Mission Application of the Advanced Electric Propulsion System (AEPS)

NASA Technical Reports Server (NTRS)

Herman, Daniel A.; Tofil, Todd A.; Santiago, Walter; Kamhawi, Hani; Polk, James E.; Snyder, John S.; Hofer, Richard R.; Picha, Frank Q.; Jackson, Jerry; Allen, May

2018-01-01

NASA remains committed to the development and demonstration of a high-power solar electric propulsion capability for the Agency. NASA is continuing to develop the 14 kW Advanced Electric Propulsion System (AEPS), which has recently completed an Early Integrated System Test and System Preliminary Design Review. NASA continues to pursue Solar Electric Propulsion (SEP) Technology Demonstration Mission partners and mature high-power SEP mission concepts. The recent announcement of the development of a Power and Propulsion Element (PPE) as the first element of an evolvable human architecture to Mars has replaced the Asteroid Redirect Robotic Mission (ARRM) as the most probable first application of the AEPS Hall thruster system. This high-power SEP capability, or an extensible derivative of it, has been identified as a critical part of an affordable, beyond-low-Earth-orbit, manned exploration architecture. This paper presents the status of the combined NASA and Aerojet Rocketdyne AEPS development activities and updated mission concept for implementation of the AEPS hardware as part of the ion propulsion system for a PPE.

Research and technology, fiscal year 1986, Marshall Space Flight Center

NASA Technical Reports Server (NTRS)

1986-01-01

The Marshall Space Flight Center is continuing its vigorous efforts in space-related research and technology. Extensive activities in advanced studies have led to the approval of the Orbital Maneuvering Vehicle as a new start. Significant progress was made in definition studies of liquid rocket engine systems for future space transportation needs and the conceptualization of advanced laucnch vehicles. The space systems definition studies have brought the Advanced X-ray Astrophysics Facility and Gravity Probe-B to a high degree of maturity. Both are ready for project implementation. Also discussed include significant advances in low gravity sciences, solar terrestrial physics, high energy astrophysics, atmospheric sciences, propulsion systems, and on the critical element of the Space Shuttle Main Engine in particular. The goals of improving the productivity of high-cost repetitive operations on reusable transportation systems, and extending the useful life of such systems are examined. The research and technology highlighted provides a foundation for progress on the Hubble Space Telescope, the Space Station, all elements of the Space Transportation System, and the many other projects assigned to this Center.

Thermionic fast spectrum reactor-converter on the basis of multi-cell TFE

NASA Astrophysics Data System (ADS)

Ponomarev-Stepnoi, N. N.; Kompaniets, G. V.; Poliakov, D. N.; Stepennov, B. S.; Andreev, P. V.; Zhabotinsky, E. E.; Nikolaev, Yu. V.; Lapochkin, N. V.

2001-02-01

Today Russian experts have technological experience in development of in-core thermionic converters for reactors of space nuclear power plants. Such a converter contains nuclear fuel inside and really represents a fuel element of a reactor. Two types of reactors can be considered on the basis of these thermionic fuel elements: with thermal or intermediate neutron spectrum, and with fast neutron spectrum. The first type is characterized by the presence of moderator in core that ensures most economical usage of nuclear fuel. The estimation shows that moderated system is the most effective in the power range of about 5 ... 100 kWe. The power systems of higher level are characterized by larger dimensions due to the presence of moderator. The second type of reactor is considered for higher power levels. This power range is about hundreds kWe. Dimensions of the fast reactor and core configuration are determined by the necessity to ensure the required net output power, on the one hand, and the necessity to ensure critical state on the other hand. In the case of using in-core thermionic fuel elements of the specified design, minimal reactor output power is determined by reactor criticality condition, and maximum reactor power output is determined by specifications and launcher capabilities. In the present paper the effective multiplication factor of a fast spectrum reactor on the basis of a multi-cell TFE developed by ``Lutch'' is considered a function of the total number of TFEs in the reactor. The MCU Monte-Carlo code, developed in Russia (Alekseev, et al., 1991), was used for computations. TFE computational models are placed in the nodes of a uniform triangular lattice and surrounded with pressure vessel and a side reflector. Ordinary fuel pins without thermionic converters were used instead of some TFEs to optimize criticality parameters, dimensions and output power of the reactor. General weight parameters of the reactor are presented in the paper. .

ViDI: Virtual Diagnostics Interface. Volume 2; Unified File Format and Web Services as Applied to Seamless Data Transfer

NASA Technical Reports Server (NTRS)

Fleming, Gary A. (Technical Monitor); Schwartz, Richard J.

2004-01-01

The desire to revolutionize the aircraft design cycle from its currently lethargic pace to a fast turn-around operation enabling the optimization of non-traditional configurations is a critical challenge facing the aeronautics industry. In response, a large scale effort is underway to not only advance the state of the art in wind tunnel testing, computational modeling, and information technology, but to unify these often disparate elements into a cohesive design resource. This paper will address Seamless Data Transfer, the critical central nervous system that will enable a wide variety of varied components to work together.

Reliability and Maintainability Engineering - A Major Driver for Safety and Affordability

NASA Technical Reports Server (NTRS)

Safie, Fayssal M.

2011-01-01

The United States National Aeronautics and Space Administration (NASA) is in the midst of an effort to design and build a safe and affordable heavy lift vehicle to go to the moon and beyond. To achieve that, NASA is seeking more innovative and efficient approaches to reduce cost while maintaining an acceptable level of safety and mission success. One area that has the potential to contribute significantly to achieving NASA safety and affordability goals is Reliability and Maintainability (R&M) engineering. Inadequate reliability or failure of critical safety items may directly jeopardize the safety of the user(s) and result in a loss of life. Inadequate reliability of equipment may directly jeopardize mission success. Systems designed to be more reliable (fewer failures) and maintainable (fewer resources needed) can lower the total life cycle cost. The Department of Defense (DOD) and industry experience has shown that optimized and adequate levels of R&M are critical for achieving a high level of safety and mission success, and low sustainment cost. Also, lessons learned from the Space Shuttle program clearly demonstrated the importance of R&M engineering in designing and operating safe and affordable launch systems. The Challenger and Columbia accidents are examples of the severe impact of design unreliability and process induced failures on system safety and mission success. These accidents demonstrated the criticality of reliability engineering in understanding component failure mechanisms and integrated system failures across the system elements interfaces. Experience from the shuttle program also shows that insufficient Reliability, Maintainability, and Supportability (RMS) engineering analyses upfront in the design phase can significantly increase the sustainment cost and, thereby, the total life cycle cost. Emphasis on RMS during the design phase is critical for identifying the design features and characteristics needed for time efficient processing, improved operational availability, and optimized maintenance and logistic support infrastructure. This paper discusses the role of R&M in a program acquisition phase and the potential impact of R&M on safety, mission success, operational availability, and affordability. This includes discussion of the R&M elements that need to be addressed and the R&M analyses that need to be performed in order to support a safe and affordable system design. The paper also provides some lessons learned from the Space Shuttle program on the impact of R&M on safety and affordability.

NCC: A Multidisciplinary Design/Analysis Tool for Combustion Systems

NASA Technical Reports Server (NTRS)

Liu, Nan-Suey; Quealy, Angela

1999-01-01

A multi-disciplinary design/analysis tool for combustion systems is critical for optimizing the low-emission, high-performance combustor design process. Based on discussions between NASA Lewis Research Center and the jet engine companies, an industry-government team was formed in early 1995 to develop the National Combustion Code (NCC), which is an integrated system of computer codes for the design and analysis of combustion systems. NCC has advanced features that address the need to meet designer's requirements such as "assured accuracy", "fast turnaround", and "acceptable cost". The NCC development team is comprised of Allison Engine Company (Allison), CFD Research Corporation (CFDRC), GE Aircraft Engines (GEAE), NASA Lewis Research Center (LeRC), and Pratt & Whitney (P&W). This development team operates under the guidance of the NCC steering committee. The "unstructured mesh" capability and "parallel computing" are fundamental features of NCC from its inception. The NCC system is composed of a set of "elements" which includes grid generator, main flow solver, turbulence module, turbulence and chemistry interaction module, chemistry module, spray module, radiation heat transfer module, data visualization module, and a post-processor for evaluating engine performance parameters. Each element may have contributions from several team members. Such a multi-source multi-element system needs to be integrated in a way that facilitates inter-module data communication, flexibility in module selection, and ease of integration.

A program for advancing the technology of space concentrators

NASA Technical Reports Server (NTRS)

Naujokas, Gerald J.; Savino, Joseph M.

1989-01-01

In 1985, the NASA Lewis Research Center formed a project, the Advanced Solar Dynamics Power Systems Project, for the purpose of advancing the technology of Solar Dynamic Power Systems for space applications beyond 2000. Since then, technology development activities have been initiated for the major components and subsystems such as the concentrator, heat receiver and engine, and radiator. Described here is a program for developing long lived (10 years or more), lighter weight, and more reflective space solar concentrators than is presently possible. The program is progressing along two parallel paths: one is concentrator concept development and the other is the resolution of those critical technology issues that will lead to durable, highly specular, and lightweight reflector elements. Outlined are the specific objectives, long-term goals, approach, planned accomplishments for the future, and the present status of the various program elements.

A program for advancing the technology of space concentrators

NASA Technical Reports Server (NTRS)

Naujokas, Gerald J.; Savino, Joseph M.

1989-01-01

In 1985, the NASA Lewis Research Center formed a project, the Advanced Solar Dynamics Power Systems Project, for the purpose of advancing the technology of Solar Dynamic Power Systems for space applications beyond 2000. Since then, technology development activities have been initiated for the major components and subsystems such as the concentrator, heat receiver and engine, and radiator. Described here is a program for developing long lived (10 years or more), lighter weight, and more reflective space solar concentrators than is presently possible. The program is progressing along two parallel paths: one is concentrator concept development and the other is the resolution of those critical technology issues that will lead to durable, highly specular, and lightweight reflector elements. Outlined are the specific objectives, long term goals, approach, planned accomplishments for the future, and the present status of the various program elements.

Entropy-driven loss of gas-phase Group 5 species from GOLD/3-5 compound semiconductor systems

NASA Astrophysics Data System (ADS)

Pugh, J. H.; Williams, R. S.

1986-02-01

Temperature dependent chemical interactions between Au and nine 3-5 compound semiconductors (3=A1, Ga, In and V=P, As, Sb) have been calculated using bulk thermodynamic properties. Enthalpic considerations alone are insufficient to predict metal/compound-semiconductor reactivities. The entropy of vaporization of the group 5 elements is shown to be an extremely important driving force for chemical reactions involving the 3-5's, since it enables several endothermic reactions to occur spontaneously under certain temperature and pressure conditions. Plots of either Gibb's free energies of reaction or equilibrium vapor pressure of the group 5 element versus temperature are used to predict critical reaction temperatures for each of the systems studied. These plots agree extremely well with previous experimental observations of thin film reactions of Au on GaAs.

Nuclear Cryogenic Propulsion Stage Conceptual Design and Mission Analysis

NASA Technical Reports Server (NTRS)

Kos, Larry D.; Russell, Tiffany E.

2014-01-01

The Nuclear Cryogenic Propulsion Stage (NCPS) is an in-space transportation vehicle, comprised of three main elements, designed to support a long-stay human Mars mission architecture beginning in 2035. The stage conceptual design and the mission analysis discussed here support the current nuclear thermal propulsion going on within partnership activity of NASA and the Department of Energy (DOE). The transportation system consists of three elements: 1) the Core Stage, 2) the In-line Tank, and 3) the Drop Tank. The driving mission case is the piloted flight to Mars in 2037 and will be the main point design shown and discussed. The corresponding Space Launch System (SLS) launch vehicle (LV) is also presented due to it being a very critical aspect of the NCPS Human Mars Mission architecture due to the strong relationship between LV lift capability and LV volume capacity.

Sustainability evaluation of essential critical raw materials: cobalt, niobium, tungsten and rare earth elements

NASA Astrophysics Data System (ADS)

Tkaczyk, A. H.; Bartl, A.; Amato, A.; Lapkovskis, V.; Petranikova, M.

2018-05-01

The criticality of raw materials has become an important issue in recent years. As the supply of certain raw materials is essential for technologically-advanced economies, the European Commission and other international counterparts have started several initiatives to secure reliable and unhindered access to raw materials. Such efforts include the EU Raw Materials Initiative, European Innovation Partnership on Raw Materials, US Critical Materials Institute, and others. In this paper, the authors present a multi-faceted and multi-national review of the essentials for the critical raw materials (CRMs) Co, Nb, W, and rare earth elements (REEs). The selected CRMs are of specific interest as they are considered relevant for emerging technologies and will thus continue to be of increasing major economic importance. This paper presents a ‘sustainability evaluation’ for each element, including essential data about markets, applications and recycling, and possibilities for substitution have been summarized and analysed. All the presented elements are vital for the advanced materials and processes upon which modern societies rely. These elements exhibit superior importance in ‘green’ applications and products subject to severe conditions. The annual production quantities are quite low compared to common industrial metals. Of the considered CRMs, only Co and REE gross production exceed 100 000 t. At the same time, the prices are quite high, with W and Nb being in the range of 60 USD kg‑1 and some rare earth compounds costing almost 4000 USD kg‑1. Despite valiant effort, in practice some of the considered elements are de facto irreplaceable for many specialized applications, at today’s technological level. Often, substitution causes a significant loss of quality and performance. Furthermore, possible candidates for substitution may be critical themselves or available in considerably low quantities. It can be concluded that one preferred approach for the investigated elements could be the use of secondary resources derived from recycling. W exhibits the highest recycling rate (37%), whereas Co (16%), Nb (11%) and rare earths (~0%) lag behind. In order to promote recycling of these essential elements, financial incentives as well as an improvement of recycling technologies would be required.

Autothermal reforming catalyst having perovskite structure

DOEpatents

Krumpel, Michael [Naperville, IL; Liu, Di-Jia [Naperville, IL

2009-03-24

The invention addressed two critical issues in fuel processing for fuel cell application, i.e. catalyst cost and operating stability. The existing state-of-the-art fuel reforming catalyst uses Rh and platinum supported over refractory oxide which add significant cost to the fuel cell system. Supported metals agglomerate under elevated temperature during reforming and decrease the catalyst activity. The catalyst is a perovskite oxide or a Ruddlesden-Popper type oxide containing rare-earth elements, catalytically active firs row transition metal elements, and stabilizing elements, such that the catalyst is a single phase in high temperature oxidizing conditions and maintains a primarily perovskite or Ruddlesden-Popper structure under high temperature reducing conditions. The catalyst can also contain alkaline earth dopants, which enhance the catalytic activity of the catalyst, but do not compromise the stability of the perovskite structure.

Materials for high-density electronic packaging and interconnection

NASA Technical Reports Server (NTRS)

1990-01-01

Electronic packaging and interconnections are the elements that today limit the ultimate performance of advanced electronic systems. Materials in use today and those becoming available are critically examined to ascertain what actions are needed for U.S. industry to compete favorably in the world market for advanced electronics. Materials and processes are discussed in terms of the final properties achievable and systems design compatibility. Weak points in the domestic industrial capability, including technical, industrial philosophy, and political, are identified. Recommendations are presented for actions that could help U.S. industry regain its former leadership position in advanced semiconductor systems production.

Influence Map Methodology for Evaluating Systemic Safety Issues

NASA Technical Reports Server (NTRS)

2008-01-01

"Raising the bar" in safety performance is a critical challenge for many organizations, including Kennedy Space Center. Contributing-factor taxonomies organize information about the reasons accidents occur and therefore are essential elements of accident investigations and safety reporting systems. Organizations must balance efforts to identify causes of specific accidents with efforts to evaluate systemic safety issues in order to become more proactive about improving safety. This project successfully addressed the following two problems: (1) methods and metrics to support the design of effective taxonomies are limited and (2) influence relationships among contributing factors are not explicitly modeled within a taxonomy.

Criticality in Bulk Metallic Glass Constituent Elements

NASA Astrophysics Data System (ADS)

Mota, Rodrigo Miguel Ojeda; Graedel, T. E.; Pekarskaya, Evgenia; Schroers, Jan

2017-11-01

Bulk metallic glasses (BMGs), which readily form amorphous phases during solidification, are increasingly being used in first applications of watch components, electronic casings, and sporting goods. The compositions of BMGs typically include four to six elements. Various political and geological factors have recently led to supply disruptions for several metals, including some present in BMG compositions. In this work, we assess the "criticality" of 22 technologically interesting BMG compositions, compare the results with those for three common engineering alloy groups, and derive recommendations for BMG composition choices from a criticality perspective. The criticality of BMGs is found to be generally much higher compared with those for the established engineering alloys. Therefore, criticality concerns should also be considered in the choice between existing and developing novel BMGs.

The critical binary star separation for a planetary system origin of white dwarf pollution

NASA Astrophysics Data System (ADS)

Veras, Dimitri; Xu, Siyi; Rebassa-Mansergas, Alberto

2018-01-01

The atmospheres of between one quarter and one half of observed single white dwarfs in the Milky Way contain heavy element pollution from planetary debris. The pollution observed in white dwarfs in binary star systems is, however, less clear, because companion star winds can generate a stream of matter which is accreted by the white dwarf. Here, we (i) discuss the necessity or lack thereof of a major planet in order to pollute a white dwarf with orbiting minor planets in both single and binary systems, and (ii) determine the critical binary separation beyond which the accretion source is from a planetary system. We hence obtain user-friendly functions relating this distance to the masses and radii of both stars, the companion wind, and the accretion rate on to the white dwarf, for a wide variety of published accretion prescriptions. We find that for the majority of white dwarfs in known binaries, if pollution is detected, then that pollution should originate from planetary material.

Addressing overuse of health services in health systems: a critical interpretive synthesis.

PubMed

Ellen, Moriah E; Wilson, Michael G; Vélez, Marcela; Shach, Ruth; Lavis, John N; Grimshaw, Jeremy M; Moat, Kaelan A

2018-06-15

Health systems are increasingly focusing on the issue of 'overuse' of health services and how to address it. We developed a framework focused on (1) the rationale and context for health systems prioritising addressing overuse, (2) elements of a comprehensive process and approach to reduce overuse and (3) implementation considerations for addressing overuse. We conducted a critical interpretive synthesis informed by a stakeholder-engagement process. The synthesis identified relevant empirical and non-empirical articles about system-level overuse. Two reviewers independently screened records, assessed for inclusion and conceptually mapped included articles. From these, we selected a purposive sample, created structured summaries of key findings and thematically synthesised the results. Our search identified 3545 references, from which we included 251. Most articles (76%; n = 192) were published within 5 years of conducting the review and addressed processes for addressing overuse (63%; n = 158) or political and health system context (60%; n = 151). Besides negative outcomes at the patient, system and global level, there were various contextual factors to addressing service overuse that seem to be key issue drivers. Processes for addressing overuse can be grouped into three elements comprising a comprehensive approach, including (1) approaches to identify overused health services, (2) stakeholder- or patient-led approaches and (3) government-led initiatives. Key implementation considerations include the need to develop 'buy in' from stakeholders and citizens. Health systems want to ensure the use of high-value services to keep citizens healthy and avoid harm. Our synthesis can be used by policy-makers, stakeholders and researchers to understand how the issue has been prioritised, what approaches have been used to address it and implementation considerations. PROSPERO CRD42014013204 .

Active and adaptive Legionella CRISPR-Cas reveals a recurrent challenge to the pathogen.

PubMed

Rao, Chitong; Guyard, Cyril; Pelaz, Carmen; Wasserscheid, Jessica; Bondy-Denomy, Joseph; Dewar, Ken; Ensminger, Alexander W

2016-10-01

Clustered regularly interspaced short palindromic repeats with CRISPR-associated gene (CRISPR-Cas) systems are widely recognized as critical genome defense systems that protect microbes from external threats such as bacteriophage infection. Several isolates of the intracellular pathogen Legionella pneumophila possess multiple CRISPR-Cas systems (type I-C, type I-F and type II-B), yet the targets of these systems remain unknown. With the recent observation that at least one of these systems (II-B) plays a non-canonical role in supporting intracellular replication, the possibility remained that these systems are vestigial genome defense systems co-opted for other purposes. Our data indicate that this is not the case. Using an established plasmid transformation assay, we demonstrate that type I-C, I-F and II-B CRISPR-Cas provide protection against spacer targets. We observe efficient laboratory acquisition of new spacers under 'priming' conditions, in which initially incomplete target elimination leads to the generation of new spacers and ultimate loss of the invasive DNA. Critically, we identify the first known target of L. pneumophila CRISPR-Cas: a 30 kb episome of unknown function whose interbacterial transfer is guarded against by CRISPR-Cas. We provide evidence that the element can subvert CRISPR-Cas by mutating its targeted sequences - but that primed spacer acquisition may limit this mechanism of escape. Rather than generally impinging on bacterial fitness, this element drives a host specialization event - with improved fitness in Acanthamoeba but a reduced ability to replicate in other hosts and conditions. These observations add to a growing body of evidence that host range restriction can serve as an existential threat to L. pneumophila in the wild. © 2016 The Authors Cellular Microbiology Published by John Wiley & Sons Ltd.

Evolution of supercritical fluid in deeply subducted continental crust: a case study of composite granite-quartz veins in the Sulu belt, China

NASA Astrophysics Data System (ADS)

Wang, S.; Wang, L.; Brown, M.

2016-12-01

Although fluid plays a key role in element transport and rock strength during subduction to and exhumation from ultrahigh pressure (UHP) metamorphic conditions, the source of supercritical fluid at P above the second critical endpoints (SCE) and the subsequent evolution are not well constrained. To provide insight into the evolution of supercritical fluid in continental subduction zones, we undertook an integrated study of composite granite-quartz veins in retrogressed and migmatitic UHP eclogite at General's Hill, N of Qingdao, in the central Sulu belt. The composite veins are irregularly distributed in the eclogite, which occurs as blocks within gneiss. The granite component is enriched in large ion lithophile elements and light rare earth elements but depleted in high field strength elements and heavy rare earth elements, indicating crystallization from a melt phase of crustal origin. Additionally, the granite contains high modal phengite (22-30 vol%) and clinozoisite/epidote (3-10 vol%), implying precipitation from a H2O-rich silicate melt. By contrast, the quartz component is dominated by SiO2 (99.10 wt%), and contains low total rare earth elements (ΣREE = 0.46 ppm), indicating precipitation from an aqueous fluid. The crystallization age of the composite veins is 221 ± 2 Ma, which is younger than the UHP metamorphism in the Sulu belt at ca 230 Ma, consistent with formation during exhumation. Initial 176Hf/177Hf ratios and δ18O values of metamorphic zircons from the composite veins, and Sr-Nd isotope compositions of the granites all lie between values for eclogite and gneiss, indicating a mixed source. Accordingly, we propose that a supercritical fluid generated from the gneiss and the included blocks of eclogite at P-T conditions above the SCE for both compositions became trapped in the eclogite during exhumation. At P below the SCE for the hydrous granite system, the mixed supercritical fluid separated into immiscible aqueous melt and aqueous fluid and crystallized as the composite veins. Thus, these vein systems provide information critical to understanding the evolution of supercritical fluid during exhumation and the partitioning of elements between hydrous granite and aqueous fluid. These data inform our understanding of crust-mantle interactions in continental subduction zones.

Overview of the NCC

NASA Technical Reports Server (NTRS)

Liu, Nan-Suey

2001-01-01

A multi-disciplinary design/analysis tool for combustion systems is critical for optimizing the low-emission, high-performance combustor design process. Based on discussions between then NASA Lewis Research Center and the jet engine companies, an industry-government team was formed in early 1995 to develop the National Combustion Code (NCC), which is an integrated system of computer codes for the design and analysis of combustion systems. NCC has advanced features that address the need to meet designer's requirements such as "assured accuracy", "fast turnaround", and "acceptable cost". The NCC development team is comprised of Allison Engine Company (Allison), CFD Research Corporation (CFDRC), GE Aircraft Engines (GEAE), NASA Glenn Research Center (LeRC), and Pratt & Whitney (P&W). The "unstructured mesh" capability and "parallel computing" are fundamental features of NCC from its inception. The NCC system is composed of a set of "elements" which includes grid generator, main flow solver, turbulence module, turbulence and chemistry interaction module, chemistry module, spray module, radiation heat transfer module, data visualization module, and a post-processor for evaluating engine performance parameters. Each element may have contributions from several team members. Such a multi-source multi-element system needs to be integrated in a way that facilitates inter-module data communication, flexibility in module selection, and ease of integration. The development of the NCC beta version was essentially completed in June 1998. Technical details of the NCC elements are given in the Reference List. Elements such as the baseline flow solver, turbulence module, and the chemistry module, have been extensively validated; and their parallel performance on large-scale parallel systems has been evaluated and optimized. However the scalar PDF module and the Spray module, as well as their coupling with the baseline flow solver, were developed in a small-scale distributed computing environment. As a result, the validation of the NCC beta version as a whole was quite limited. Current effort has been focused on the validation of the integrated code and the evaluation/optimization of its overall performance on large-scale parallel systems.

Orbital design strategy for domestic communication satellite systems.

NASA Technical Reports Server (NTRS)

Ramji, S.; Sawitz, P.

1973-01-01

Review of some of the considerations pertinent to efficient orbit utilization in the design of domestic communications satellite systems. A strategy is developed to efficiently locate a heterogeneous system of satellites within the available arc and provide room for future growth. A practical design is illustrated, using a computer simulation model, for the placement of 25 satellites within 73% of the available arc employing frequency and polarization coordination techniques. A number of widely variable factors that influence satellite spacing are examined. These factors include such critical system elements as telephony and television interference noise limits, frequency plan coordination, polarization plan coordination, ground antenna diameter, signal protection ratio, and satellite station keeping.

Suicide Prevention: Critical Elements for Managing Suicidal Clients and Counselor Liability Without the Use of a No-Suicide Contract

ERIC Educational Resources Information Center

Lee, Jeane B.; Bartlett, Mary L.

2005-01-01

Despite its entrenchment as a standard of practice, no-suicide contracts fail to achieve their purpose as an effective part of treatment or as an effective method of inoculating counselors against potential lawsuits should a client commit suicide. Critical elements for managing suicidal clients and counselor liability without reliance on the…

NASA'S Water Resources Element Within the Applied Sciences Program

NASA Technical Reports Server (NTRS)

Toll, David; Doorn, Bradley; Engman, Edwin

2010-01-01

The NASA Applied Sciences Program works within NASA Earth sciences to leverage investment of satellite and information systems to increase the benefits to society through the widest practical use of NASA research results. Such observations provide a huge volume of valuable data in both near-real-time and extended back nearly 50 years about the Earth's land surface conditions such as land cover type, vegetation type and health, precipitation, snow, soil moisture, and water levels and radiation. Observations of this type combined with models and analysis enable satellite-based assessment of numerous water resources management activities. The primary goal of the Earth Science Applied Science Program is to improve future and current operational systems by infusing them with scientific knowledge of the Earth system gained through space-based observation, model results, and development and deployment of enabling technologies, systems, and capabilities. Water resources is one of eight elements in the Applied Sciences Program and it addresses concerns and decision making related to water quantity and water quality. With increasing population pressure and water usage coupled with climate variability and change, water issues are being reported by numerous groups as the most critical environmental problems facing us in the 21st century. Competitive uses and the prevalence of river basins and aquifers that extend across boundaries engender political tensions between communities, stakeholders and countries. Mitigating these conflicts and meeting water demands requires using existing resources more efficiently. The potential crises and conflicts arise when water is competed among multiple uses. For example, urban areas, environmental and recreational uses, agriculture, and energy production compete for scarce resources, not only in the Western U.S. but throughout much of the U.S. but also in many parts of the world. In addition to water availability issues, water quality related problems are seriously affecting human health and our environment. The NASA Water Resources Program Element works to use NASA products to address these critical issues.

Photomask CD and LER characterization using Mueller matrix spectroscopic ellipsometry

NASA Astrophysics Data System (ADS)

Heinrich, A.; Dirnstorfer, I.; Bischoff, J.; Meiner, K.; Ketelsen, H.; Richter, U.; Mikolajick, T.

2014-10-01

Critical dimension and line edge roughness on photomask arrays are determined with Mueller matrix spectroscopic ellipsometry. Arrays with large sinusoidal perturbations are measured for different azimuth angels and compared with simulations based on rigorous coupled wave analysis. Experiment and simulation show that line edge roughness leads to characteristic changes in the different Mueller matrix elements. The influence of line edge roughness is interpreted as an increase of isotropic character of the sample. The changes in the Mueller matrix elements are very similar when the arrays are statistically perturbed with rms roughness values in the nanometer range suggesting that the results on the sinusoidal test structures are also relevant for "real" mask errors. Critical dimension errors and line edge roughness have similar impact on the SE MM measurement. To distinguish between both deviations, a strategy based on the calculation of sensitivities and correlation coefficients for all Mueller matrix elements is shown. The Mueller matrix elements M13/M31 and M34/M43 are the most suitable elements due to their high sensitivities to critical dimension errors and line edge roughness and, at the same time, to a low correlation coefficient between both influences. From the simulated sensitivities, it is estimated that the measurement accuracy has to be in the order of 0.01 and 0.001 for the detection of 1 nm critical dimension error and 1 nm line edge roughness, respectively.

Development and deployment of a passive sampling system in groundwater to characterize the critical zone through isotope tracing

NASA Astrophysics Data System (ADS)

Gal, Frédérick; Négrel, Philippe; Chagué, Bryan

2017-04-01

The Critical Zone (CZ) is the evolving boundary layer where rock, soil, water, air, and living organisms interact, zone controlling the transfer and storage of water and chemical elements. For investigating the CZ, we have developed an integrative sampling system to concentrate the chemical elements in groundwater (CRITEX project). Aims are to measure concentrations and isotopic ratios in groundwater through integrative sampling. In the frame of the groundwater analysis, particularly those located in the critical zone (0-100 m depth), this system makes it possible to create a water flow in a support of passive samplers using Diffusive Gradient in Thin type (DGT) and thus to pre-concentrate the chemical species on a chelating resin by diffusion through a membrane and over a given period in order to facilitate subsequent laboratory measurements. Because DGTs are generally used in surface waters with a high flow rate, the current objective is to create a sufficient flow of water in the sampler to optimize the trapping of elements. Different options and geometries have been modelled by simulation of the flow (agitation of water supplied by a motor and a propeller, pumping ...). The economic model of the device is based on an assembly of commercially available equipment, the novation is based on the support, fully designed in house (patent pending). The device aims to recreate sufficient water flow to avoid the creation of a too large Diffusion Boundary Layer (DBL) on the DGT surface and then to mimic the uptake conditions that prevail in surface waters. The simulations made it possible to optimize the position of the DGT and the velocity of the fluid in order to obtain the maximum flow at its surface and avoid the creation of the DBL. Conditions equivalent to those of a circulation of weakly agitated surface water are thus recreated. The first tests were carried out at lab, in a column simulating a piezometer, including pump, DGT holder and flow meter. Initial functional tests were carried out with tap water to observe the flow of water in the device, to determine the technical characteristics of the system (current, voltage, flow...) and to perform blank measurements to ensure that the device brings no contamination. We then carried out 6 days of immersion of the system on a piezometer of the BRGM site. In parallel, daily sampling was performed using conventional pumping method. Finally, we carried out tests on drillings in the Coët Dan experimental basin (Naizin, Morbihan, France). We established a screening of chemical elements on which isotopic measurements can be done by comparing the accumulated mass in the DGT with respect to the concentration of the elements in water. This suggests that the isotopic determination is possible for U, Sr, Nd and Ni with the exception of Cu and Zn at the moment. Possible contamination of DGTs themselves and/or during field investigations should be further studied in order to rule if Cu or Zn isotope analyses can be foreseen in the future.

Nucleosynthesis: Stellar and Solar Abundances and Atomic Data

NASA Technical Reports Server (NTRS)

Cowan, John J.; Lawler, James E.; Sneden, Christopher; DenHartog, E. A.; Collier, Jason; Dodge, Homer L.

2006-01-01

Abundance observations indicate the presence of often surprisingly large amounts of neutron capture (i.e., s- and r-process) elements in old Galactic halo and globular cluster stars. These observations provide insight into the nature of the earliest generations of stars in the Galaxy the progenitors of the halo stars responsible for neutron-capture synthesis. Comparisons of abundance trends can be used to understand the chemical evolution of the Galaxy and the nature of heavy element nucleosynthesis. In addition age determinations, based upon long-lived radioactive nuclei abundances, can now be obtained. These stellar abundance determinations depend critically upon atomic data. Improved laboratory transition probabilities have been recently obtained for a number of elements. These new gf values have been used to greatly refine the abundances of neutron-capture elemental abundances in the solar photosphere and in very metal-poor Galactic halo stars. The newly determined stellar abundances are surprisingly consistent with a (relative) Solar System r-process pattern, and are also consistent with abundance predictions expected from such neutron-capture nucleosynthesis.

Electronic Repair Concepts for Long-Duration Spaceflight

NASA Technical Reports Server (NTRS)

Easton, John; Pettegrew, Richard D.; Struk, Peter M.

2007-01-01

Constraints on the mass and volume that can be allocated for electronics spares and repair equipment on long-duration space missions mean that NASA must look at repair strategies beyond the traditional approach, which has been to replace faulty subsystems in a modular form, termed Orbital Replacement Units or Line Replacement Units. Other possible strategies include component and board-level replacement, modular designs that allow reprogramming of less-critical systems to take the place of more critical failed systems, and a blended approach which uses elements of each of these approaches, along with a limited number of Line Replacement Units. This paper presents some of the constraints and considerations that affect the decision on how to approach electronics repair for long duration space missions, and discusses the benefits and limitations of each of the previously mentioned strategies.

The NPOESS Preparatory Project Science Data Segment: Brief Overview

NASA Technical Reports Server (NTRS)

Schweiss, Robert J.; Ho, Evelyn; Ullman, Richard; Samadi, Shahin

2006-01-01

The NPOESS Preparatory Project (NPP) provides remotely-sensed land, ocean, atmospheric, ozone, and sounder data that will serve the meteorological and global climate change scientific communities while also providing risk reduction for the National Polar-orbiting Operational Environmental Satellite System (NPOESS), the U.S. Government s future low-Earth orbiting satellite system monitoring global weather and environmental conditions. NPOESS and NPP are a new era, not only because the sensors will provide unprecedented quality and volume of data but also because it is a joint mission of three federal agencies, NASA, NOAA, and DoD. NASA's primary science role in NPP is to independently assess the quality of the NPP science and environmental data records. Such assessment is critical for making NPOESS products the best that they can be for operational use and ultimately for climate studies. The Science Data Segment (SDS) supports science assessment by assuring the timely provision of NPP data to NASA s science teams organized by climate measurement themes. The SDS breaks down into nine major elements, an input element that receives data from the operational agencies and acts as a buffer, a calibration analysis element, five elements devoted to measurement based quality assessment, an element used to test algorithmic improvements, and an element that provides overall science direction. This paper will describe how the NPP SDS will leverage on NASA experience to provide a mission-reliable research capability for science assessment of NPP derived measurements.

Integrated homeland security system with passive thermal imaging and advanced video analytics

NASA Astrophysics Data System (ADS)

Francisco, Glen; Tillman, Jennifer; Hanna, Keith; Heubusch, Jeff; Ayers, Robert

2007-04-01

A complete detection, management, and control security system is absolutely essential to preempting criminal and terrorist assaults on key assets and critical infrastructure. According to Tom Ridge, former Secretary of the US Department of Homeland Security, "Voluntary efforts alone are not sufficient to provide the level of assurance Americans deserve and they must take steps to improve security." Further, it is expected that Congress will mandate private sector investment of over $20 billion in infrastructure protection between 2007 and 2015, which is incremental to funds currently being allocated to key sites by the department of Homeland Security. Nearly 500,000 individual sites have been identified by the US Department of Homeland Security as critical infrastructure sites that would suffer severe and extensive damage if a security breach should occur. In fact, one major breach in any of 7,000 critical infrastructure facilities threatens more than 10,000 people. And one major breach in any of 123 facilities-identified as "most critical" among the 500,000-threatens more than 1,000,000 people. Current visible, nightvision or near infrared imaging technology alone has limited foul-weather viewing capability, poor nighttime performance, and limited nighttime range. And many systems today yield excessive false alarms, are managed by fatigued operators, are unable to manage the voluminous data captured, or lack the ability to pinpoint where an intrusion occurred. In our 2006 paper, "Critical Infrastructure Security Confidence Through Automated Thermal Imaging", we showed how a highly effective security solution can be developed by integrating what are now available "next-generation technologies" which include: Thermal imaging for the highly effective detection of intruders in the dark of night and in challenging weather conditions at the sensor imaging level - we refer to this as the passive thermal sensor level detection building block Automated software detection for creating initial alerts - we refer to this as software level detection, the next level building block Immersive 3D visual assessment for situational awareness and to manage the reaction process - we refer to this as automated intelligent situational awareness, a third building block Wide area command and control capabilities to allow control from a remote location - we refer to this as the management and process control building block integrating together the lower level building elements. In addition, this paper describes three live installations of complete, total systems that incorporate visible and thermal cameras as well as advanced video analytics. Discussion of both system elements and design is extensive.

Tracking progress: Applying the Forest Service 10 Year Wilderness Stewardship Challenge as a model of performance management

Treesearch

Liese C. Dean

2007-01-01

The USDA Forest Service applied a performance management/ accountability system to the 407 wildernesses it oversees by defining and tracking critical work. Work elements were consolidated and packaged into the “10 Year Wilderness Stewardship Challenge.” The goal of the Challenge is to have 100 percent of wildernesses administered by the Forest Service managed to a...

P21 Common Core Toolkit: A Guide to Aligning the Common Core State Standards with the Framework for 21st Century Skills

ERIC Educational Resources Information Center

Partnership for 21st Century Skills, 2011

2011-01-01

Standards drive critical elements of the American educational system--the curricula that schools follow, the textbooks students read, and the tests they take. Similarly, standards establish the levels of performance that students, teachers and schools are expected to meet. To succeed in the 21st century, all students will need to perform to high…

Air Force Office of Scientific Research, 1993 Research Highlights.

DTIC Science & Technology

1993-01-01

used to describe the behavior of critical point phenomena by Nobel laureate Dr. Kenneth Wilson. Their research has produced useful engineering...40 years of its existence, AFOSR has supported the work of about two dozen scientists who, later, have been awarded the Nobel prize as well as a...locations and types of sensor or actuator elements that are suitable for structurally- integrated nondestructive evaluation ( NDE ) systems. The basic

2008 Defense Industrial Base Critical Infrastructure Protection Conference (DIB-CBIP)

DTIC Science & Technology

2008-04-09

a cloak -and- dagger thing. It’s about computer architecture and the soundness of electronic systems." Joel Brenner, ODNI Counterintelligence Office...to support advanced network exploitation and launch attacks on the informational and physical elements of our cyber infrastructure. In order to...entities and is vulnerable to attacks and manipulation. Operations in the cyber domain have the ability to impact operations in other war-fighting

Analysis of Instructional Support Elements for an Online, Educational Simulation on Active Listening for Women Graduate Students in Science and Engineering

ERIC Educational Resources Information Center

Bernstein, Bianca L.; Bekki, Jennifer M.; Wilkins, Kerrie G.; Harrison, Caroline J.

2016-01-01

Strong interpersonal communication skills (ICS) are critical for educational and career success, but effective and widely accessible training systems are not available. This paper describes a 2 × 2 × 2 experimental study of an online, educational simulation for practice with the ICS of active listening. The simulation was customized for women…

Human exploration mission studies

NASA Technical Reports Server (NTRS)

Cataldo, Robert L.

1990-01-01

This paper describes several case studies of human space exploration, considered by the NASA's Office of Exploration in 1988. Special attention is given to the mission scenarios, the critical technology required in these expeditions, and the extraterrestrial power requirements of significant system elements. The cases examined include a manned expedition to Phobos, the inner Martian moon; a human expedition to Mars; the Lunar Observatory; and a lunar outpost to early Mars evolution.

Saliva as a Diagnostic Fluid

PubMed Central

Malamud, Daniel; Rodriguez-Chavez, Isaac R.

2010-01-01

Synopsis Salivary diagnostics is a dynamic and emerging field utilizing nanotechnology and molecular diagnostics to aid in the diagnosis of oral and systemic diseases. Here, we critically review the latest advances using oral biomarkers for disease detection. The use of oral fluids is broadening perspectives in clinical diagnosis, disease monitoring and decision making for patient care. Important elements determining the future possibilities and challenges in this field are also discussed. PMID:21094724

Human factors in spacecraft design

NASA Technical Reports Server (NTRS)

Harrison, Albert A.; Connors, Mary M.

1990-01-01

This paper describes some of the salient implications of evolving mission parameters for spacecraft design. Among the requirements for future spacecraft are new, higher standards of living, increased support of human productivity, and greater accommodation of physical and cultural variability. Design issues include volumetric allowances, architecture and layouts, closed life support systems, health maintenance systems, recreational facilities, automation, privacy, and decor. An understanding of behavioral responses to design elements is a precondition for critical design decisions. Human factors research results must be taken into account early in the course of the design process.

87Sr/86Sr and 143Nd/144Nd for disentangling anthropogenic and natural REE contributions in river water during flood events.

NASA Astrophysics Data System (ADS)

Hissler, Christophe; Stille, Peter; Pfister, Laurent

2017-04-01

The sustainable management of water resources is one of the greatest challenges of the 21st century. Water is a vital resource that is increasingly put under pressure from multiple perspectives. While the global population is on the rise, socio-economic development makes equally rapid progress - eventually compromising access to clean water bodies. Multiple pollution sources constitute an immediate threat to aquatic ecosystems and are likely to cause long lasting contaminations of water bodies that are critical for drinking and/or irrigation water production. There is a pressing need for an adequate quantification of anthropogenic impacts on the critical zone of river basins and the identification of the temporal dynamics of these impacts. As an example, despite the work done to assess the environmental impact of REE pollutions in larger river systems, we are still lacking information on the dynamics of these anthropogenic compounds in relation to rapid hydrological changes. Filling these knowledge gaps is a pre-requisite for the design and implementation of sustainable water resources management strategies. In order to better constrain the relative contributions of both anthropogenic and geogenic trace element sources we propose using a multitracer approach combining elemental and 87Sr/86Sr, 143Nd/144Nd, and 206Pb/207Pb isotopic ratios. The use of these three separate isotopic systems together with REE concentrations is new in the field of anthropogenic source identification in river systems. We observed enrichments in Anthropogenic Rare Earth Elements (AREE) for dissolved Gd and suspended Nd loads of river water. With increasing discharge, AREE anomalies progressively disappeared and gave way to the geogenic chemical signature of the basin in both dissolved and suspended loads. The isotopic data confirm these observations and shed new light on the trace elements sources. On the one hand, dissolved loads have peculiar isotopic characteristics and carry mainly limestone-derived and anthropogenic Sr and Nd as well as significant amounts of anthropogenic Pb. On the other hand, the results clearly indicate that anthropogenic contributions impact the suspended loads in all hydrological conditions. This study demonstrates that (i) the composition of the AREE pool is characteristic of a given river basin and controlled by the different anthropogenic contributions located in a specific study area and (ii) the anthropogenic contributions to the river may change not only Pb, but also Sr and Nd isotopic compositions in both dissolved and suspended loads. This is of importance for future provenance studies in the critical zone of polluted river basins.

A demonstration of real-time connected element interferometry for spacecraft navigation

NASA Technical Reports Server (NTRS)

Edwards, C.; Rogstad, D.; Fort, D.; White, L.; Iijima, B.

1992-01-01

Connected element interferometry is a technique of observing a celestial radio source at two spatially separated antennas, and then interfering the received signals to extract the relative phase of the signal at the two antennas. The high precision of the resulting phase delay data type can provide an accurate determination of the angular position of the radio source relative to the baseline vector between the two stations. A connected element interferometer on a 21-km baseline between two antennas at the Deep Space Network's Goldstone, CA tracking complex is developed. Fiber optic links are used to transmit the data at 112 Mbit/sec to a common site for processing. A real-time correlator to process these data in real-time is implemented. The architecture of the system is described, and observational data is presented to characterize the potential performance of such a system. The real-time processing capability offers potential advantages in terms of increased reliability and improved delivery of navigational data for time-critical operations. Angular accuracies of 50-100 nrad are achievable on this baseline.

Resonance of magnetization excited by voltage in magnetoelectric heterostructures

NASA Astrophysics Data System (ADS)

Yu, Guoliang; Zhang, Huaiwu; Li, Yuanxun; Li, Jie; Zhang, Dainan; Sun, Nian

2018-04-01

Manipulation of magnetization dynamics is critical for spin-based devices. Voltage driven magnetization resonance is promising for realizing low-power information processing systems. Here, we show through Finite Element Method (FEM) simulations that magnetization resonance in nanoscale magnetic elements can be generated by a radio frequency (rf) voltage via the converse magnetoelectric (ME) effect. The magnetization dynamics induced by voltage in a ME heterostructures is simulated by taking into account the magnetoelastic and piezoelectric coupling mechanisms among magnetization, strain and voltage. The frequency of the excited magnetization resonance is equal to the driving rf voltage frequency. The proposed voltage driven magnetization resonance excitation mechanism opens a way toward energy-efficient spin based device applications.

Finite Element Analysis and Test Results Comparison for the Hybrid Wing Body Center Section Test Article

NASA Technical Reports Server (NTRS)

Przekop, Adam; Jegley, Dawn C.; Rouse, Marshall; Lovejoy, Andrew E.

2016-01-01

This report documents the comparison of test measurements and predictive finite element analysis results for a hybrid wing body center section test article. The testing and analysis efforts were part of the Airframe Technology subproject within the NASA Environmentally Responsible Aviation project. Test results include full field displacement measurements obtained from digital image correlation systems and discrete strain measurements obtained using both unidirectional and rosette resistive gauges. Most significant results are presented for the critical five load cases exercised during the test. Final test to failure after inflicting severe damage to the test article is also documented. Overall, good comparison between predicted and actual behavior of the test article is found.

Radiation source with shaped emission

DOEpatents

Kubiak, Glenn D.; Sweatt, William C.

2003-05-13

Employing a source of radiation, such as an electric discharge source, that is equipped with a capillary region configured into some predetermined shape, such as an arc or slit, can significantly improve the amount of flux delivered to the lithographic wafers while maintaining high efficiency. The source is particularly suited for photolithography systems that employs a ringfield camera. The invention permits the condenser which delivers critical illumination to the reticle to be simplified from five or more reflective elements to a total of three or four reflective elements thereby increasing condenser efficiency. It maximizes the flux delivered and maintains a high coupling efficiency. This architecture couples EUV radiation from the discharge source into a ring field lithography camera.

Linkages Between Critical Wedges and Crustal Channels Using 2-D Coupled Thermomechanical Finite Element Models: Implications for Himalayan Orogenic Evolution

NASA Astrophysics Data System (ADS)

Sparks, S. A.; Thigpen, J. R.

2017-12-01

In continental tectonics, questions remain regarding the dominant mechanisms of shortening accommodation during orogen evolution. Two quantitatively-supported models, critical wedge and channel flow, have been applied to the Himalaya and proposed for other large collisional systems. These two models represent fundamentally distinct mechanisms for accommodating shortening in collisional systems and until recently have been viewed as mutually exclusive. While there remains support for these mechanisms being incompatible end-members, in more recent studies it has been proposed that either: (1) both geodynamic mechanisms may operate simultaneously yet in spatially distinct parts of the larger composite orogenic system or (2) both mechanisms are present yet they operate at temporally distinct intervals, wherein the orogen progressively develops through stages dominated by mid-crustal channel flow followed by shallow thrust stacking and duplex development. In both scenarios, the mechanism active at each stage in orogen evolution is presumably dependent upon local to regional scale rheological conditions (as a function of orogen dynamic and thermal evolution) that are likely to be transient in both space and time. However, questions regarding the dynamic, mechanical, and thermal-kinematic relationships of such a system remain. Also, while field observations and deformation records derived from analyses of transects within the Himalaya can be interpreted in such a way to be consistent with a unified model, numerical models that predict the behavior of interactions between the end-member models have - until now - not existed. Here, we present results from 2-D coupled thermomechanical finite-element numerical experiments that examine the necessary conditions for mechanical compatibility between the channel and critical wedge by focusing on the role of rheology. These model results will eventually allow us to make preliminary comparisons between model-derived stress predictions and differential stress values determined from quartz paleopiezometry from samples collected in the Langtang and Annapurna regions of central Nepal.

Stable mineral recrystallization in low temperature aqueous systems: A critical review

NASA Astrophysics Data System (ADS)

Gorski, Christopher A.; Fantle, Matthew S.

2017-02-01

Minerals may undergo recrystallization reactions in low temperature (<100 °C) aqueous systems, during which they exchange isotopes and trace elements with the dissolved reservoir without undergoing overt structural, bulk compositional, or morphological changes. These interfacial reactions, which are often referred to in the literature as "atom exchange" and herein as "stable mineral recrystallization", have important implications for the use of isotopic and elemental proxies to interpret past temperatures, oxidation states, and aqueous chemistries on Earth. The reactions are also significant for modern environments, including engineered systems, as they imply that mineral lattices may be substantially more open to exchanging toxic elements and radionuclides with coexisting solutions than previously thought. To date, observations of stable mineral recrystallization are distributed among several disciplines, and no work has attempted to review their findings comprehensively. Accordingly, this review article presents laboratory evidence for stable mineral recrystallization, describes data collection and interpretation strategies, summarizes similar recrystallization systematics observed in multiple studies, explores the potential occurrence of stable mineral recrystallization in natural systems, and discusses possible mechanisms by which stable mineral recrystallization occurs. The review focuses primarily on carbonates, sulfates, and iron oxides because these minerals have been studied most extensively to date. The review concludes by presenting key questions that should be addressed in this field to further understand and account for stable mineral recrystallization in natural and engineered aqueous systems at low temperatures.

A general architecture for intelligent training systems

NASA Technical Reports Server (NTRS)

Loftin, R. Bowen

1987-01-01

A preliminary design of a general architecture for autonomous intelligent training systems was developed. The architecture integrates expert system technology with teaching/training methodologies to permit the production of systems suitable for use by NASA, other government agencies, industry, and academia in the training of personnel for the performance of complex, mission-critical tasks. The proposed architecture consists of five elements: a user interface, a domain expert, a training session manager, a trainee model, and a training scenario generator. The design of this architecture was guided and its efficacy tested through the development of a system for use by Mission Control Center Flight Dynamics Officers in training to perform Payload-Assist Module Deploys from the orbiter.

Lasercom system architecture with reduced complexity

NASA Technical Reports Server (NTRS)

Lesh, James R. (Inventor); Chen, Chien-Chung (Inventor); Ansari, Homayoon (Inventor)

1994-01-01

Spatial acquisition and precision beam pointing functions are critical to spaceborne laser communication systems. In the present invention, a single high bandwidth CCD detector is used to perform both spatial acquisition and tracking functions. Compared to previous lasercom hardware design, the array tracking concept offers reduced system complexity by reducing the number of optical elements in the design. Specifically, the design requires only one detector and one beam steering mechanism. It also provides the means to optically close the point-ahead control loop. The technology required for high bandwidth array tracking was examined and shown to be consistent with current state of the art. The single detector design can lead to a significantly reduced system complexity and a lower system cost.

LaserCom System Architecture With Reduced Complexity

NASA Technical Reports Server (NTRS)

Lesh, James R. (Inventor); Chen, Chien-Chung (Inventor); Ansari, Homa-Yoon (Inventor)

1996-01-01

Spatial acquisition and precision beam pointing functions are critical to spaceborne laser communication systems. In the present invention a single high bandwidth CCD detector is used to perform both spatial acquisition and tracking functions. Compared to previous lasercom hardware design, the array tracking concept offers reduced system complexity by reducing the number of optical elements in the design. Specifically, the design requires only one detector and one beam steering mechanism. It also provides means to optically close the point-ahead control loop. The technology required for high bandwidth array tracking was examined and shown to be consistent with current state of the art. The single detector design can lead to a significantly reduced system complexity and a lower system cost.

A new holistic approach to vulnerability assessment to natural hazards of socio-economic systems by means of Graph Theory

NASA Astrophysics Data System (ADS)

Arosio, Marcello; Martina, Mario L. V.

2017-04-01

In the last years, the relations and interactions between multi-hazards, vulnerability, exposure and resilience spheres are assuming more and more attention and the scientific community recognized that they are very dynamic, complex and interconnected. The traditional approaches define risk as the potential economic, social and environmental consequences due to a hazardous phenomenon in a specific period. Although there have been major improvements in recent years, there are still some limitation in term of a holistic approach that is able to include the emergent value hidden in the relation and interaction between the different spheres. Furthermore, the emergent behaviour of a society makes the collective risk greater than the sum of the parts and this requires a holistic, systematic and integrated approach. For this reason, it is important to consider the connections between elements to assess properly the vulnerability of systems. In a system (e.g. road, hospital and ecological network, etc.), or in a System of System (e.g. socio-technical urban service), there are critical elements that, beyond the intrinsic vulnerability, can be characterize by greater or lower vulnerability because of their physical, geographical, cyber or logical connections. To understand the system response to a perturbation, and therefore its resilience, is necessary not only to represent but also to quantify the relative importance of the elements and their interconnections. To this aim, we propose an innovative approach in the field of natural risk assessment based on the properties of graph G=(N,L). A graph consists of two sets N (nodes) and L (links): the nodes represent the single exposed elements (physical, social, environmental, etc.) to a hazard, while the links (or connections) represent the interaction between the elements. This approach encourages the risk assessment to a new prospective: from reductionist to holistic. The final goal is to provide insight in understanding how to quantify integrated collective vulnerability, resilience and risk.

Variations in Party Line Information Requirements for Flight Crew Situation Awareness in the Datalink Environment

NASA Technical Reports Server (NTRS)

Pritchett, Amy R.; Hansman, R. John

1994-01-01

Current Air Traffic Control communications use shared very high frequency (VHF) voice frequencies from which pilots can obtain 'Party Line' Information (PLI) by overhearing communications addressed to other aircraft. A prior study has shown pilots perceive this PLI to be important. There is concern that some critical PLI may be lost in the proposed datalink environment where communications will be discretely addressed. Different types of flight operations will be, equipped with datalink equipment at different times, generating a 'mixed environment' where some pilots may rely on PLI while others will receive their information by datalink. To research the importance, availability and accuracy of PLI and to query pilots on the information they feel is necessary, a survey was distributed to pilots. The pilots were selected from four flight operation groups to study the variations in PLI requirements in the mixed datalink environment. Pilots perceived PLI to be important overall. Specific information elements pertaining to traffic and weather information were identified as Critical. Most PLI elements followed a pattern of higher perceived importance during terminal area operations, final approach and landing. Pilots from the different flight operation groups identified some elements as particularly important. Pilots perceived PLI to be only moderately available and accurate overall. Several PLI elements received very low availability and accuracy ratings but are perceived as important. In a free response question designed to find the information requirements for global situation awareness, pilots frequently indicated a need for traffic and weather information. These elements were also frequently cited by them as information that could be presented by a datalink system. The results of this survey identify specific concerns to be addressed when implementing datalink communications.

Infiltration behaviour of elemental mercury DNAPL in fully and partially water saturated porous media

NASA Astrophysics Data System (ADS)

D'Aniello, Andrea; Hartog, Niels; Sweijen, Thomas; Pianese, Domenico

2018-02-01

Mercury is a contaminant of global concern due to its harmful effects on human health and for the detrimental consequences of its release in the environment. Sources of liquid elemental mercury are usually anthropogenic, such as chlor-alkali plants. To date insight into the infiltration behaviour of liquid elemental mercury in the subsurface is lacking, although this is critical for assessing both characterization and remediation approaches for mercury DNAPL contaminated sites. Therefore, in this study the infiltration behaviour of elemental mercury in fully and partially water saturated systems was investigated using column experiments. The properties affecting the constitutive relations governing the infiltration behaviour of liquid Hg0, and PCE for comparison, were determined using Pc(S) experiments with different granular porous media (glass beads and sands) for different two- and three-phase configurations. Results showed that, in water saturated porous media, elemental mercury, as PCE, acted as a non-wetting fluid. The required entry head for elemental mercury was higher (from about 5 to 7 times). However, due to the almost tenfold higher density of mercury, the required NAPL entry heads of 6.19 cm and 12.51 cm for mercury to infiltrate were 37.5% to 20.7% lower than for PCE for the same porous media. Although Leverett scaling was able to reproduce the natural tendency of Hg0 to be more prone than PCE to infiltrate in water saturated porous media, it considerably underestimated Hg0 infiltration capacity in comparison with the experimental results. In the partially water saturated system, in contrast with PCE, elemental mercury also acted as a nonwetting fluid, therefore having to overcome an entry head to infiltrate. The required Hg0 entry heads (10.45 and 15.74 cm) were considerably higher (68.9% and 25.8%) than for the water saturated porous systems. Furthermore, in the partially water saturated systems, experiments showed that elemental mercury displaced both air and water, depending on the initial water distribution within the pores. This indicates that the conventional wettability hierarchy, in which the NAPL has an intermediate wetting state between the air and the water phases, is not valid for liquid elemental mercury. Therefore, for future modelling of elemental mercury DNAPL infiltration behaviour in variably water saturated porous media, a different formulation of the governing constitutive relations will be required.

Micro-optics for microfluidic analytical applications.

PubMed

Yang, Hui; Gijs, Martin A M

2018-02-19

This critical review summarizes the developments in the integration of micro-optical elements with microfluidic platforms for facilitating detection and automation of bio-analytical applications. Micro-optical elements, made by a variety of microfabrication techniques, advantageously contribute to the performance of an analytical system, especially when the latter has microfluidic features. Indeed the easy integration of optical control and detection modules with microfluidic technology helps to bridge the gap between the macroscopic world and chip-based analysis, paving the way for automated and high-throughput applications. In our review, we start the discussion with an introduction of microfluidic systems and micro-optical components, as well as aspects of their integration. We continue with a detailed description of different microfluidic and micro-optics technologies and their applications, with an emphasis on the realization of optical waveguides and microlenses. The review continues with specific sections highlighting the advantages of integrated micro-optical components in microfluidic systems for tackling a variety of analytical problems, like cytometry, nucleic acid and protein detection, cell biology, and chemical analysis applications.

Localization of multiple defects using the compact phased array (CPA) method

NASA Astrophysics Data System (ADS)

Senyurek, Volkan Y.; Baghalian, Amin; Tashakori, Shervin; McDaniel, Dwayne; Tansel, Ibrahim N.

2018-01-01

Array systems of transducers have found numerous applications in detection and localization of defects in structural health monitoring (SHM) of plate-like structures. Different types of array configurations and analysis algorithms have been used to improve the process of localization of defects. For accurate and reliable monitoring of large structures by array systems, a high number of actuator and sensor elements are often required. In this study, a compact phased array system consisting of only three piezoelectric elements is used in conjunction with an updated total focusing method (TFM) for localization of single and multiple defects in an aluminum plate. The accuracy of the localization process was greatly improved by including wave propagation information in TFM. Results indicated that the proposed CPA approach can locate single and multiple defects with high accuracy while decreasing the processing costs and the number of required transducers. This method can be utilized in critical applications such as aerospace structures where the use of a large number of transducers is not desirable.

Design approach of an aquaculture cage system for deployment in the constructed channel flow environments of a power plant

PubMed Central

Lee, Jihoon; Fredriksson, David W.; DeCew, Judson; Drach, Andrew; Yim, Solomon C.

2018-01-01

This study provides an engineering approach for designing an aquaculture cage system for use in constructed channel flow environments. As sustainable aquaculture has grown globally, many novel techniques have been introduced such as those implemented in the global Atlantic salmon industry. The advent of several highly sophisticated analysis software systems enables the development of such novel engineering techniques. These software systems commonly include three-dimensional (3D) drafting, computational fluid dynamics, and finite element analysis. In this study, a combination of these analysis tools is applied to evaluate a conceptual aquaculture system for potential deployment in a power plant effluent channel. The channel is supposedly clean; however, it includes elevated water temperatures and strong currents. The first portion of the analysis includes the design of a fish cage system with specific net solidities using 3D drafting techniques. Computational fluid dynamics is then applied to evaluate the flow reduction through the system from the previously generated solid models. Implementing the same solid models, a finite element analysis is performed on the critical components to assess the material stresses produced by the drag force loads that are calculated from the fluid velocities. PMID:29897954

Independent Orbiter Assessment (IOA): Analysis of the extravehicular mobility unit

NASA Technical Reports Server (NTRS)

Raffaelli, Gary G.

1986-01-01

The results of the Independent Orbiter Assessment (IOA) of the Failure Modes and Effects Analysis (FMEA) and Critical Items List (CIL) are presented. The IOA approach features a top-down analysis of the hardware to determine failure modes, criticality, and potential critical items (PCIs). To preserve independence, this analysis was accomplished without reliance upon the results contained within the NASA FMEA/CIL documentation. This report documents the independent analysis results corresponding to the Extravehicular Mobility Unit (EMU) hardware. The EMU is an independent anthropomorphic system that provides environmental protection, mobility, life support, and communications for the Shuttle crewmember to perform Extravehicular Activity (EVA) in Earth orbit. Two EMUs are included on each baseline Orbiter mission, and consumables are provided for three two-man EVAs. The EMU consists of the Life Support System (LSS), Caution and Warning System (CWS), and the Space Suit Assembly (SSA). Each level of hardware was evaluated and analyzed for possible failure modes and effects. The majority of these PCIs are resultant from failures which cause loss of one or more primary functions: pressurization, oxygen delivery, environmental maintenance, and thermal maintenance. It should also be noted that the quantity of PCIs would significantly increase if the SOP were to be treated as an emergency system rather than as an unlike redundant element.

Beyond adaptive-critic creative learning for intelligent mobile robots

NASA Astrophysics Data System (ADS)

Liao, Xiaoqun; Cao, Ming; Hall, Ernest L.

2001-10-01

Intelligent industrial and mobile robots may be considered proven technology in structured environments. Teach programming and supervised learning methods permit solutions to a variety of applications. However, we believe that to extend the operation of these machines to more unstructured environments requires a new learning method. Both unsupervised learning and reinforcement learning are potential candidates for these new tasks. The adaptive critic method has been shown to provide useful approximations or even optimal control policies to non-linear systems. The purpose of this paper is to explore the use of new learning methods that goes beyond the adaptive critic method for unstructured environments. The adaptive critic is a form of reinforcement learning. A critic element provides only high level grading corrections to a cognition module that controls the action module. In the proposed system the critic's grades are modeled and forecasted, so that an anticipated set of sub-grades are available to the cognition model. The forecasting grades are interpolated and are available on the time scale needed by the action model. The success of the system is highly dependent on the accuracy of the forecasted grades and adaptability of the action module. Examples from the guidance of a mobile robot are provided to illustrate the method for simple line following and for the more complex navigation and control in an unstructured environment. The theory presented that is beyond the adaptive critic may be called creative theory. Creative theory is a form of learning that models the highest level of human learning - imagination. The application of the creative theory appears to not only be to mobile robots but also to many other forms of human endeavor such as educational learning and business forecasting. Reinforcement learning such as the adaptive critic may be applied to known problems to aid in the discovery of their solutions. The significance of creative theory is that it permits the discovery of the unknown problems, ones that are not yet recognized but may be critical to survival or success.

KSC-00pp1054

NASA Image and Video Library

2000-07-31

The Zenith-1 (Z-1) Truss, the cornerstone truss of the Space Station, is shown on the floor of the Space Station Processing Facility. The Z-1 Truss was officially turned over to NASA from The Boeing Co. on July 31. It is scheduled to fly in Space Shuttle Discovery's payload pay on STS-92 targeted for launch Oct. 5, 2000. The Z-1 is considered a cornerstone truss because it carries critical components of the Station's attitude, communications, thermal and power control systems as well as four control moment gyros, high and low gain antenna systems, and two plasma contactor units used to disperse electrical charge build-ups. The Z-1 truss and a Pressurized Mating Adapter (PMA-3), also flying to the Station on the same mission, will be the first major U.S. elements flown to the ISS aboard the Shuttle since the launch of the Unity element in December 1998

Fabrication of microfluidic integrated biosensor

NASA Astrophysics Data System (ADS)

Adam, Tijjani; Dhahi, Th S.; Mohammed, Mohammed; Hashim, U.; Noriman, N. Z.; Dahham, Omar S.

2017-09-01

An event of miniaturizing for sensor systems to carry out biological diagnostics are gaining wade spread acceptance. The system may contain several different sensor units for the detection of specific analyte, the analyte to be detected might be any kind of biological molecules (DNA, mRNA or proteins) or chemical substances. In most cases, the detection is based on receptor-ligand binding like DNA hybridization or antibody-antigen interaction, achieving this on a nanostructure. DNA or protein must be attached to certain locations within the structure. Critical for this is to have a robust binding chemistry to the surface in the microstructure. Here we successfully designed and fabricated microfluidics element for passive fluid delivery into polysilicon Nanowire sensing domain, we further demonstrated a very simple and effective way of integrating the two devices to give full functionalities of laboratory on a single chip. The sensing element was successfully surface modified and tested on real biomedical clinical sample for evaluation and validation.

On the stability analysis of hyperelastic boundary value problems using three- and two-field mixed finite element formulations

NASA Astrophysics Data System (ADS)

Schröder, Jörg; Viebahn, Nils; Wriggers, Peter; Auricchio, Ferdinando; Steeger, Karl

2017-09-01

In this work we investigate different mixed finite element formulations for the detection of critical loads for the possible occurrence of bifurcation and limit points. In detail, three- and two-field formulations for incompressible and quasi-incompressible materials are analyzed. In order to apply various penalty functions for the volume dilatation in displacement/pressure mixed elements we propose a new consistent scheme capturing the non linearities of the penalty constraints. It is shown that for all mixed formulations, which can be reduced to a generalized displacement scheme, a straight forward stability analysis is possible. However, problems based on the classical saddle-point structure require a different analyses based on the change of the signature of the underlying matrix system. The basis of these investigations is the work from Auricchio et al. (Comput Methods Appl Mech Eng 194:1075-1092, 2005, Comput Mech 52:1153-1167, 2013).

Web-Based Intervention for Women With Type 1 Diabetes in Pregnancy and Early Motherhood: Critical Analysis of Adherence to Technological Elements and Study Design.

PubMed

Berg, Marie; Linden, Karolina; Adolfsson, Annsofie; Sparud Lundin, Carina; Ranerup, Agneta

2018-05-02

Numerous Web-based interventions have been implemented to promote health and health-related behaviors in persons with chronic conditions. Using randomized controlled trials to evaluate such interventions creates a range of challenges, which in turn can influence the study outcome. Applying a critical perspective when evaluating Web-based health interventions is important. The objective of this study was to critically analyze and discuss the challenges of conducting a Web-based health intervention as a randomized controlled trial. The MODIAB-Web study was critically examined using an exploratory case study methodology and the framework for analysis offered through the Persuasive Systems Design model. Focus was on technology, study design, and Web-based support usage, with special focus on the forum for peer support. Descriptive statistics and qualitative content analysis were used. The persuasive content and technological elements in the design of the randomized controlled trial included all four categories of the Persuasive Systems Design model, but not all design principles were implemented. The study duration was extended to a period of four and a half years. Of 81 active participants in the intervention group, a maximum of 36 women were simultaneously active. User adherence varied greatly with a median of 91 individual log-ins. The forum for peer support was used by 63 participants. Although only about one-third of the participants interacted in the forum, there was a fairly rich exchange of experiences and advice between them. Thus, adherence in terms of social interactions was negatively affected by limited active participation due to prolonged recruitment process and randomization effects. Lessons learned from this critical analysis are that technology and study design matter and might mutually influence each other. In Web-based interventions, the use of design theories enables utilization of the full potential of technology and promotes adherence. The randomization element in a randomized controlled trial design can become a barrier to achieving a critical mass of user interactions in Web-based interventions, especially when social support is included. For extended study periods, the technology used may need to be adapted in line with newly available technical options to avoid the risk of becoming outdated in the user realm, which in turn might jeopardize study validity in terms of randomized controlled trial designs. On the basis of lessons learned in this randomized controlled trial, we give recommendations to consider when designing and evaluating Web-based health interventions. ©Marie Berg, Karolina Linden, Annsofie Adolfsson, Carina Sparud Lundin, Agneta Ranerup. Originally published in the Journal of Medical Internet Research (http://www.jmir.org), 02.05.2018.

AST Critical Propulsion and Noise Reduction Technologies for Future Commercial Subsonic Engines Area of Interest 1.0: Reliable and Affordable Control Systems

NASA Technical Reports Server (NTRS)

Myers, William; Winter, Steve

2006-01-01

The General Electric Reliable and Affordable Controls effort under the NASA Advanced Subsonic Technology (AST) Program has designed, fabricated, and tested advanced controls hardware and software to reduce emissions and improve engine safety and reliability. The original effort consisted of four elements: 1) a Hydraulic Multiplexer; 2) Active Combustor Control; 3) a Variable Displacement Vane Pump (VDVP); and 4) Intelligent Engine Control. The VDVP and Intelligent Engine Control elements were cancelled due to funding constraints and are reported here only to the state they progressed. The Hydraulic Multiplexing element developed and tested a prototype which improves reliability by combining the functionality of up to 16 solenoids and servo-valves into one component with a single electrically powered force motor. The Active Combustor Control element developed intelligent staging and control strategies for low emission combustors. This included development and tests of a Controlled Pressure Fuel Nozzle for fuel sequencing, a Fuel Multiplexer for individual fuel cup metering, and model-based control logic. Both the Hydraulic Multiplexer and Controlled Pressure Fuel Nozzle system were cleared for engine test. The Fuel Multiplexer was cleared for combustor rig test which must be followed by an engine test to achieve full maturation.

The constructed catchment Chicken Creek as Critical Zone Observatory under transition

NASA Astrophysics Data System (ADS)

Gerwin, Werner; Schaaf, Wolfgang; Elmer, Michael; Hinz, Christoph

2014-05-01

The constructed catchment Chicken Creek was established in 2005 as an experimental landscape laboratory for ecosystem research. The 6 ha area with clearly defined horizontal as well as vertical boundary conditions was left for an unrestricted primary succession. All Critical Zone elements are represented at this site, which allows the study of most processes occurring at the interface of bio-, pedo-, geo- and hydrosphere. It provides outstanding opportunities for investigating interactions and feedbacks between different evolving compartments during ecosystem development. The catchment is extensively instrumented since 2005 in order to detect transition stages of the ecosystem. Data recorded with a high spatial and temporal resolution include hydrological, geomorphological, pedological, limnological as well as biological parameters. In contrast to other Critical Zone Observatories, this site offers the unique situation of an early stage ecosystem with highly dynamic system properties. The first years of development were characterized by a fast formation of geomorphological structures due to massive erosion processes at the initially non-vegetated surface. Hydrological processes led to the establishment of a local groundwater body within 5 years. In the following years the influence of biological structures like vegetation patterns gained an increasing importance. Feedbacks between developing vegetation and e.g. hydrological features became more and more dominant. As a result, different phases of ecosystem development could be distinguished until now. This observatory offers manifold possibilities to identify and disentangle complex interactions between Critical Zone processes in situ under natural conditions. The originally low complexity of the system is growing with time facilitating the identification of influences of newly developing structures on system functions. Thus, it is possible to study effects of small-scale processes on the whole system at the landscape scale. In addition, the highly dynamic initial system properties allow the observation of multifaceted changes of Critical Zone properties and functions within short periods of time. Chicken Creek could complement the existing network of Critical Zone Observatories which are usually established at ecosystems in a mature state.

A Critical Analysis of the Common Elements of a High School Social Justice Curriculum: Quantitative Research vs. Qualitative Research

ERIC Educational Resources Information Center

Hartlep, Nicholas Daniel

2010-01-01

The topic of this article is high school social justice curriculum [SJC]. Three socially-just focused studies were critically analyzed. Sample sizes in these studies varied from n = 12 to n = 55. It is the author's belief, based on the research of others (Kerssen-Griep & Eifler, 2008) that an effective SJC should consist of the following elements:…

Lockheed Martin approach to a Reusable Launch Vehicle (RLV)

NASA Astrophysics Data System (ADS)

Elvin, John D.

1996-03-01

This paper discusses Lockheed Martin's perspective on the development of a cost effective Reusable Launch Vehicle (RLV). Critical to a successful Single Stage To Orbit (SSTO) program are; an economic development plan sensitive to fiscal constraints; a vehicle concept satisfying present and future US launch needs; and an operations concept commensurate with a market driven program. Participation in the economic plan by government, industry, and the commercial sector is a key element of integrating our development plan and funding profile. The RLV baseline concept design, development evolution and several critical trade studies illustrate the superior performance achieved by our innovative approach to the problem of SSTO. Findings from initial aerodynamic and aerothermodynamic wind tunnel tests and trajectory analyses on this concept confirm the superior characteristics of the lifting body shape combined with the Linear Aerospike rocket engine. This Aero Ballistic Rocket (ABR) concept captures the essence of The Skunk Works approach to SSTO RLV technology integration and system engineering. These programmatic and concept development topics chronicle the key elements to implementing an innovative market driven next generation RLV.

Implementing emergency manuals: can cognitive aids help translate best practices for patient care during acute events?

PubMed

Goldhaber-Fiebert, Sara N; Howard, Steven K

2013-11-01

In this article, we address whether emergency manuals are an effective means of helping anesthesiologists and perioperative teams apply known best practices for critical events. We review the relevant history of such cognitive aids in health care, as well as examples from other high stakes industries, and describe why emergency manuals have a role in improving patient care during certain events. We propose 4 vital elements: create, familiarize, use, and integrate, necessary for the widespread, successful development, and implementation of medical emergency manuals, using the specific example of the perioperative setting. The details of each element are presented, drawing from the medical literature as well as from our combined experience of more than 30 years of observing teams of anesthesiologists managing simulated and real critical events. We emphasize the importance of training clinicians in the use of emergency manuals for education on content, format, and location. Finally, we discuss cultural readiness for change, present a system example of successful integration, and highlight the importance of further research on the implementation of emergency manuals.

Delamination analysis of metal-ceramic multilayer coatings subject to nanoindentation

DOE PAGES

Jamison, Ryan Dale; Shen, Yu -Lin

2016-01-22

Internal damage has been experimentally observed in aluminum (Al)/silicon carbide (SiC) multilayer coatings subject to nanoindentation loading. Post-indentation characterization has identified that delamination at the coating/substrate interface is the most prominent form of damage. In this study the finite element method is employed to study the effect of delamination on indentation-derived hardness and Young's modulus. The model features alternating Al/SiC nanolayers above a silicon (Si) substrate, in consistence with the actual material system used in earlier experiments. Cohesive elements with a traction–separation relationship are used to facilitate delamination along the coating/substrate interface. Delamination is observed numerically to be sensitive tomore » the critical normal and shear stresses that define the cohesive traction–separation behavior. Axial tensile stress below the edge of indentation contact is found to be the largest contributor to damage initiation and evolution. Delamination results in a decrease in both indentation-derived hardness and Young's modulus. As a result, a unique finding is that delamination can occur during the unloading process of indentation, depending on the loading condition and critical tractions.« less

Work and power fluctuations in a critical heat engine.

PubMed

Holubec, Viktor; Ryabov, Artem

2017-09-01

We investigate fluctuations of output work for a class of Stirling heat engines with working fluid composed of interacting units and compare these fluctuations to an average work output. In particular, we focus on engine performance close to a critical point where Carnot's efficiency may be attained at a finite power as reported by M. Campisi and R. Fazio [Nat. Commun. 7, 11895 (2016)2041-172310.1038/ncomms11895]. We show that the variance of work output per cycle scales with the same critical exponent as the heat capacity of the working fluid. As a consequence, the relative work fluctuation diverges unless the output work obeys a rather strict scaling condition, which would be very hard to fulfill in practice. Even under this condition, the fluctuations of work and power do not vanish in the infinite system size limit. Large fluctuations of output work thus constitute inseparable and dominant element in performance of the macroscopic heat engines close to a critical point.

Work and power fluctuations in a critical heat engine

NASA Astrophysics Data System (ADS)

Holubec, Viktor; Ryabov, Artem

2017-09-01

We investigate fluctuations of output work for a class of Stirling heat engines with working fluid composed of interacting units and compare these fluctuations to an average work output. In particular, we focus on engine performance close to a critical point where Carnot's efficiency may be attained at a finite power as reported by M. Campisi and R. Fazio [Nat. Commun. 7, 11895 (2016), 10.1038/ncomms11895]. We show that the variance of work output per cycle scales with the same critical exponent as the heat capacity of the working fluid. As a consequence, the relative work fluctuation diverges unless the output work obeys a rather strict scaling condition, which would be very hard to fulfill in practice. Even under this condition, the fluctuations of work and power do not vanish in the infinite system size limit. Large fluctuations of output work thus constitute inseparable and dominant element in performance of the macroscopic heat engines close to a critical point.

Slab melting versus slab dehydration in subduction-zone magmatism

PubMed Central

Mibe, Kenji; Kawamoto, Tatsuhiko; Matsukage, Kyoko N.; Fei, Yingwei; Ono, Shigeaki

2011-01-01

The second critical endpoint in the basalt-H2O system was directly determined by a high-pressure and high-temperature X-ray radiography technique. We found that the second critical endpoint occurs at around 3.4 GPa and 770 °C (corresponding to a depth of approximately 100 km in a subducting slab), which is much shallower than the previously estimated conditions. Our results indicate that the melting temperature of the subducting oceanic crust can no longer be defined beyond this critical condition and that the fluid released from subducting oceanic crust at depths greater than 100 km under volcanic arcs is supercritical fluid rather than aqueous fluid and/or hydrous melts. The position of the second critical endpoint explains why there is a limitation to the slab depth at which adakitic magmas are produced, as well as the origin of across-arc geochemical variations of trace elements in volcanic rocks in subduction zones. PMID:21536910

Molecular- and Domain-level Microstructure-dependent Material Model for Nano-segregated Polyurea

DTIC Science & Technology

2013-04-15

material subroutine VUMAT of ABAQUS /Explicit (Dassault Systems, 2010), a commercial finite element code. This subroutine is called by the ABAQUS solver...rate of change of the local internal thermal energy is equal to the corresponding rate of dissipative work. Critical assessment of this model identified...The model also takes into account the plastic expansion or contraction of voids and therefore the stresses are appropriately modified to account for

Leveraging Embedded Training Systems to Build Higher Level Cognitive Skills in Warfighters

DTIC Science & Technology

2009-10-01

is not just passive, waiting for key information to be presented, but is an active process . The information that is available to military pilots...train situation awareness (SA) skills and knowledge in military settings. SA is the key cognitive construct upon which decision making rests and one...task analyses in the military domain settings that reveal the critical SA elements for a given warfighter role and the challenges they must contend

Thermal analysis of the in-vessel components of the ITER plasma-position reflectometry.

PubMed

Quental, P B; Policarpo, H; Luís, R; Varela, P

2016-11-01

The ITER plasma position reflectometry system measures the edge electron density profile of the plasma, providing real-time supplementary contribution to the magnetic measurements of the plasma-wall distance. Some of the system components will be in direct sight of the plasma and therefore subject to plasma and stray radiation, which may cause excessive temperatures and stresses. In this work, thermal finite element analysis of the antenna and adjacent waveguides is conducted with ANSYS V17 (ANSYS® Academic Research, Release 17.0, 2016). Results allow the identification of critical temperature points, and solutions are proposed to improve the thermal behavior of the system.

Thermal analysis of the in-vessel components of the ITER plasma-position reflectometry

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

Quental, P. B., E-mail: pquental@ipfn.tecnico.ulisboa.pt; Policarpo, H.; Luís, R.

The ITER plasma position reflectometry system measures the edge electron density profile of the plasma, providing real-time supplementary contribution to the magnetic measurements of the plasma-wall distance. Some of the system components will be in direct sight of the plasma and therefore subject to plasma and stray radiation, which may cause excessive temperatures and stresses. In this work, thermal finite element analysis of the antenna and adjacent waveguides is conducted with ANSYS V17 (ANSYS® Academic Research, Release 17.0, 2016). Results allow the identification of critical temperature points, and solutions are proposed to improve the thermal behavior of the system.

Strategic Research Directions In Microgravity Materials Science

NASA Technical Reports Server (NTRS)

Clinton, Raymond G., Jr.; Wargo, Michael J.; Marzwell, Neville L.; Sanders, Gerald; Schlagheck, Ron; Semmes, Ed; Bassler, Julie; Cook, Beth

2004-01-01

The Office of Biological and Physical Research (OBPR) is moving aggressively to align programs, projects, and products with the vision for space exploration. Research in advanced materials is a critical element in meeting exploration goals. Research in low gravity materials science in OBPR is being focused on top priority needs in support of exploration: 1) Space Radiation Shielding; 2) In Situ Resource Utilization; 3) In Situ Fabrication and Repair; 4) Materials Science for Spacecraft and Propulsion Systems; 5) Materials Science for Advanced Life Support Systems. Roles and responsibilities in low gravity materials research for exploration between OBPR and the Office of Exploration Systems are evolving.

Gaseous fuel reactors for power systems

NASA Technical Reports Server (NTRS)

Kendall, J. S.; Rodgers, R. J.

1977-01-01

Gaseous-fuel nuclear reactors have significant advantages as energy sources for closed-cycle power systems. The advantages arise from the removal of temperature limits associated with conventional reactor fuel elements, the wide variety of methods of extracting energy from fissioning gases, and inherent low fissile and fission product in-core inventory due to continuous fuel reprocessing. Example power cycles and their general performance characteristics are discussed. Efficiencies of gaseous fuel reactor systems are shown to be high with resulting minimal environmental effects. A technical overview of the NASA-funded research program in gaseous fuel reactors is described and results of recent tests of uranium hexafluoride (UF6)-fueled critical assemblies are presented.

Reliability program requirements for aeronautical and space system contractors

NASA Technical Reports Server (NTRS)

1987-01-01

General reliability program requirements for NASA contracts involving the design, development, fabrication, test, and/or use of aeronautical and space systems including critical ground support equipment are prescribed. The reliability program requirements require (1) thorough planning and effective management of the reliability effort; (2) definition of the major reliability tasks and their place as an integral part of the design and development process; (3) planning and evaluating the reliability of the system and its elements (including effects of software interfaces) through a program of analysis, review, and test; and (4) timely status indication by formal documentation and other reporting to facilitate control of the reliability program.

Element distinctness revisited

NASA Astrophysics Data System (ADS)

Portugal, Renato

2018-07-01

The element distinctness problem is the problem of determining whether the elements of a list are distinct, that is, if x=(x_1,\\ldots ,x_N) is a list with N elements, we ask whether the elements of x are distinct or not. The solution in a classical computer requires N queries because it uses sorting to check whether there are equal elements. In the quantum case, it is possible to solve the problem in O(N^{2/3}) queries. There is an extension which asks whether there are k colliding elements, known as element k-distinctness problem. This work obtains optimal values of two critical parameters of Ambainis' seminal quantum algorithm (SIAM J Comput 37(1):210-239, 2007). The first critical parameter is the number of repetitions of the algorithm's main block, which inverts the phase of the marked elements and calls a subroutine. The second parameter is the number of quantum walk steps interlaced by oracle queries. We show that, when the optimal values of the parameters are used, the algorithm's success probability is 1-O(N^{1/(k+1)}), quickly approaching 1. The specification of the exact running time and success probability is important in practical applications of this algorithm.

Health management and controls for Earth-to-orbit propulsion systems

NASA Astrophysics Data System (ADS)

Bickford, R. L.

1995-03-01

Avionics and health management technologies increase the safety and reliability while decreasing the overall cost for Earth-to-orbit (ETO) propulsion systems. New ETO propulsion systems will depend on highly reliable fault tolerant flight avionics, advanced sensing systems and artificial intelligence aided software to ensure critical control, safety and maintenance requirements are met in a cost effective manner. Propulsion avionics consist of the engine controller, actuators, sensors, software and ground support elements. In addition to control and safety functions, these elements perform system monitoring for health management. Health management is enhanced by advanced sensing systems and algorithms which provide automated fault detection and enable adaptive control and/or maintenance approaches. Aerojet is developing advanced fault tolerant rocket engine controllers which provide very high levels of reliability. Smart sensors and software systems which significantly enhance fault coverage and enable automated operations are also under development. Smart sensing systems, such as flight capable plume spectrometers, have reached maturity in ground-based applications and are suitable for bridging to flight. Software to detect failed sensors has reached similar maturity. This paper will discuss fault detection and isolation for advanced rocket engine controllers as well as examples of advanced sensing systems and software which significantly improve component failure detection for engine system safety and health management.

Liquid Bismuth Feed System for Electric Propulsion

NASA Technical Reports Server (NTRS)

Markusic, T. E.; Polzin, K. A.; Stanojev, B. J.

2006-01-01

Operation of Hall thrusters with bismuth propellant has been shown to be a promising path toward high-power, high-performance, long-lifetime electric propulsion for spaceflight missions. For example, the VHITAL project aims td accurately, experimentally assess the performance characteristics of 10 kW-class bismuth-fed Hall thrusters - in order to validate earlier results and resuscitate a promising technology that has been relatively dormant for about two decades. A critical element of these tests will be the precise metering of propellant to the thruster, since performance cannot be accurately assessed without an accurate accounting of mass flow rate. Earlier work used a pre/post-test propellant weighing scheme that did not provide any real-time measurement of mass flow rate while the thruster was firing, and makes subsequent performance calculations difficult. The motivation of the present work was to develop a precision liquid bismuth Propellant Management System (PMS) that provides real-time propellant mass flow rate measurement and control, enabling accurate thruster performance measurements. Additionally, our approach emphasizes the development of new liquid metal flow control components and, hence, will establish a basis for the future development of components for application in spaceflight. The design of various critical components in a bismuth PMS are described - reservoir, electromagnetic pump, hotspot flow sensor, and automated control system. Particular emphasis is given to material selection and high-temperature sealing techniques. Open loop calibration test results are reported, which validate the systems capability to deliver bismuth at mass flow rates ranging from 10 to 100 mg/sec with an uncertainty of less than +/- 5%. Results of integrated vaporizer/liquid PMS tests demonstrate all of the necessary elements of a complete bismuth feed system for electric propulsion.

Teaching Critical Reflection. Trends and Issues Alerts.

ERIC Educational Resources Information Center

Imel, Susan

Recently, the topic of reflection and the development of reflective practitioners have received a great deal of attention. Four elements are central to critical reflection: assumption analysis, contextual awareness, imaginative speculation, and reflective skepticism. Definitions of critical reflection often reveal differing theoretical…

System-Level Planning, Coordination, and Communication

PubMed Central

Kanter, Robert K.; Dries, David; Luyckx, Valerie; Lim, Matthew L.; Wilgis, John; Anderson, Michael R.; Sarani, Babak; Hupert, Nathaniel; Mutter, Ryan; Devereaux, Asha V.; Christian, Michael D.; Kissoon, Niranjan; Christian, Michael D.; Devereaux, Asha V.; Dichter, Jeffrey R.; Kissoon, Niranjan; Rubinson, Lewis; Amundson, Dennis; Anderson, Michael R.; Balk, Robert; Barfield, Wanda D.; Bartz, Martha; Benditt, Josh; Beninati, William; Berkowitz, Kenneth A.; Daugherty Biddison, Lee; Braner, Dana; Branson, Richard D; Burkle, Frederick M.; Cairns, Bruce A.; Carr, Brendan G.; Courtney, Brooke; DeDecker, Lisa D.; De Jong, Marla J.; Dominguez-Cherit, Guillermo; Dries, David; Einav, Sharon; Erstad, Brian L.; Etienne, Mill; Fagbuyi, Daniel B.; Fang, Ray; Feldman, Henry; Garzon, Hernando; Geiling, James; Gomersall, Charles D.; Grissom, Colin K.; Hanfling, Dan; Hick, John L.; Hodge, James G.; Hupert, Nathaniel; Ingbar, David; Kanter, Robert K.; King, Mary A.; Kuhnley, Robert N.; Lawler, James; Leung, Sharon; Levy, Deborah A.; Lim, Matthew L.; Livinski, Alicia; Luyckx, Valerie; Marcozzi, David; Medina, Justine; Miramontes, David A.; Mutter, Ryan; Niven, Alexander S.; Penn, Matthew S.; Pepe, Paul E.; Powell, Tia; Prezant, David; Reed, Mary Jane; Rich, Preston; Rodriquez, Dario; Roxland, Beth E.; Sarani, Babak; Shah, Umair A.; Skippen, Peter; Sprung, Charles L.; Subbarao, Italo; Talmor, Daniel; Toner, Eric S.; Tosh, Pritish K.; Upperman, Jeffrey S.; Uyeki, Timothy M.; Weireter, Leonard J.; West, T. Eoin; Wilgis, John; Ornelas, Joe; McBride, Deborah; Reid, David; Baez, Amado; Baldisseri, Marie; Blumenstock, James S.; Cooper, Art; Ellender, Tim; Helminiak, Clare; Jimenez, Edgar; Krug, Steve; Lamana, Joe; Masur, Henry; Mathivha, L. Rudo; Osterholm, Michael T.; Reynolds, H. Neal; Sandrock, Christian; Sprecher, Armand; Tillyard, Andrew; White, Douglas; Wise, Robert; Yeskey, Kevin

2014-01-01

BACKGROUND: System-level planning involves uniting hospitals and health systems, local/regional government agencies, emergency medical services, and other health-care entities involved in coordinating and enabling care in a major disaster. We reviewed the literature and sought expert opinions concerning system-level planning and engagement for mass critical care due to disasters or pandemics and offer suggestions for system-planning, coordination, communication, and response. The suggestions in this chapter are important for all of those involved in a pandemic or disaster with multiple critically ill or injured patients, including front-line clinicians, hospital administrators, and public health or government officials. METHODS: The American College of Chest Physicians (CHEST) consensus statement development process was followed in developing suggestions. Task Force members met in person to develop nine key questions believed to be most relevant for system-planning, coordination, and communication. A systematic literature review was then performed for relevant articles and documents, reports, and other publications reported since 1993. No studies of sufficient quality were identified upon which to make evidence-based recommendations. Therefore, the panel developed expert opinion-based suggestions using a modified Delphi process. RESULTS: Suggestions were developed and grouped according to the following thematic elements: (1) national government support of health-care coalitions/regional health authorities (HC/RHAs), (2) teamwork within HC/RHAs, (3) system-level communication, (4) system-level surge capacity and capability, (5) pediatric patients and special populations, (6) HC/RHAs and networks, (7) models of advanced regional care systems, and (8) the use of simulation for preparedness and planning. CONCLUSIONS: System-level planning is essential to provide care for large numbers of critically ill patients because of disaster or pandemic. It also entails a departure from the routine, independent system and involves all levels from health-care institutions to regional health authorities. National government support is critical, as are robust communication systems and advanced planning supported by realistic exercises. PMID:25144713

Flight telerobotic servicer legacy

NASA Astrophysics Data System (ADS)

Shattuck, Paul L.; Lowrie, James W.

1992-11-01

The Flight Telerobotic Servicer (FTS) was developed to enhance and provide a safe alternative to human presence in space. The first step for this system was a precursor development test flight (DTF-1) on the Space Shuttle. DTF-1 was to be a pathfinder for manned flight safety of robotic systems. The broad objectives of this mission were three-fold: flight validation of telerobotic manipulator (design, control algorithms, man/machine interfaces, safety); demonstration of dexterous manipulator capabilities on specific building block tasks; and correlation of manipulator performance in space with ground predictions. The DTF-1 system is comprised of a payload bay element (7-DOF manipulator with controllers, end-of-arm gripper and camera, telerobot body with head cameras and electronics module, task panel, and MPESS truss) and an aft flight deck element (force-reflecting hand controller, crew restraint, command and display panel and monitors). The approach used to develop the DTF-1 hardware, software and operations involved flight qualification of components from commercial, military, space, and R controller, end-of-arm tooling, force/torque transducer) and the development of the telerobotic system for space applications. The system is capable of teleoperation and autonomous control (advances state of the art); reliable (two-fault tolerance); and safe (man-rated). Benefits from the development flight included space validation of critical telerobotic technologies and resolution of significant safety issues relating to telerobotic operations in the Shuttle bay or in the vicinity of other space assets. This paper discusses the lessons learned and technology evolution that stemmed from developing and integrating a dexterous robot into a manned system, the Space Shuttle. Particular emphasis is placed on the safety and reliability requirements for a man-rated system as these are the critical factors which drive the overall system architecture. Other topics focused on include: task requirements and operational concepts for servicing and maintenance of space platforms; origins of technology for dexterous robotic systems; issues associated with space qualification of components; and development of the industrial base to support space robotics.

Eight critical factors in creating and implementing a successful simulation program.

PubMed

Lazzara, Elizabeth H; Benishek, Lauren E; Dietz, Aaron S; Salas, Eduardo; Adriansen, David J

2014-01-01

Recognizing the need to minimize human error and adverse events, clinicians, researchers, administrators, and educators have strived to enhance clinicians' knowledge, skills, and attitudes through training. Given the risks inherent in learning new skills or advancing underdeveloped skills on actual patients, simulation-based training (SBT) has become an invaluable tool across the medical education spectrum. The large simulation, training, and learning literature was used to provide a synthesized yet innovative and "memorable" heuristic of the important facets of simulation program creation and implementation, as represented by eight critical "S" factors-science, staff, supplies, space, support, systems, success, and sustainability. These critical factors advance earlier work that primarily focused on the science of SBT success, to also include more practical, perhaps even seemingly obvious but significantly challenging components of SBT, such as resources, space, and supplies. SYSTEMS: One of the eight critical factors-systems-refers to the need to match fidelity requirements to training needs and ensure that technological infrastructure is in place. The type of learning objectives that the training is intended to address should determine these requirements. For example, some simulators emphasize physical fidelity to enable clinicians to practice technical and nontechnical skills in a safe environment that mirrors real-world conditions. Such simulators are most appropriate when trainees are learning how to use specific equipment or conduct specific procedures. The eight factors-science, staff, supplies, space, support, systems, success, and sustainability-represent a synthesis of the most critical elements necessary for successful simulation programs. The order of the factors does not represent a deliberate prioritization or sequence, and the factors' relative importance may change as the program evolves.

Analysis of Space Station Centrifuge Rotor Bearing Systems: A Case Study

NASA Technical Reports Server (NTRS)

Poplawski, Joseph V.; Loewenthal, Stuart H.; Oswald, Fred B.; Zaretsky, Erwin V.; Morales, Wilfredo; Street, Kenneth W., Jr.

2014-01-01

A team of NASA bearing and lubrication experts was assembled to assess the risk for the rolling-element bearings used in the International Space Station (ISS) centrifuge rotor (CR) to seize or otherwise fail to survive for the required 10-year life. The CR was designed by the Japan Aerospace Exploration Agency and their subcontractor, NEC Toshiba Space Systems, Ltd. (NTSpace). The NASA team performed a design audit for the most critical rolling-element bearing systems and reviewed the lubricant selected. There is uncertainty regarding the ability of the Braycote 601 grease (Castrol Limited) to reliably provide the 10-year continuous life required without relubrication of the system. The fatigue life of the Rotor Shaft Assembly (RSA) spring loaded face-to-face mount at a 99-percent probability of survival (L1 life) for the ball bearing set was estimated at 700 million hours and the single ball bearing (Row 3) at 58 million hours. These lives satisfy the mission requirements for fatigue. Rolling-element seizure tests on the RSA and fluid slip joint bearings were found unlikely to stop the centrifuge, which can cause damage to the ISS structure. The spin motor encoder duplex angular-contact ball bearings have a hard preload and a large number of small balls have the highest risk of failure. These bearings were not tested for seizure even though they are less tolerant to debris or internal clearance reductions.

Binary Phase Diagrams and Thermodynamic Properties of Silicon and Essential Doping Elements (Al, As, B, Bi, Ga, In, N, P, Sb and Tl)

PubMed Central

Mostafa, Ahmad; Medraj, Mamoun

2017-01-01

Fabrication of solar and electronic silicon wafers involves direct contact between solid, liquid and gas phases at near equilibrium conditions. Understanding of the phase diagrams and thermochemical properties of the Si-dopant binary systems is essential for providing processing conditions and for understanding the phase formation and transformation. In this work, ten Si-based binary phase diagrams, including Si with group IIIA elements (Al, B, Ga, In and Tl) and with group VA elements (As, Bi, N, P and Sb), have been reviewed. Each of these systems has been critically discussed on both aspects of phase diagram and thermodynamic properties. The available experimental data and thermodynamic parameters in the literature have been summarized and assessed thoroughly to provide consistent understanding of each system. Some systems were re-calculated to obtain a combination of the best evaluated phase diagram and a set of optimized thermodynamic parameters. As doping levels of solar and electronic silicon are of high technological importance, diffusion data has been presented to serve as a useful reference on the properties, behavior and quantities of metal impurities in silicon. This paper is meant to bridge the theoretical understanding of phase diagrams with the research and development of solar-grade silicon production, relying on the available information in the literature and our own analysis. PMID:28773034

Applications of finite-size scaling for atomic and non-equilibrium systems

NASA Astrophysics Data System (ADS)

Antillon, Edwin A.

We apply the theory of Finite-size scaling (FSS) to an atomic and a non-equilibrium system in order to extract critical parameters. In atomic systems, we look at the energy dependence on the binding charge near threshold between bound and free states, where we seek the critical nuclear charge for stability. We use different ab initio methods, such as Hartree-Fock, Density Functional Theory, and exact formulations implemented numerically with the finite-element method (FEM). Using Finite-size scaling formalism, where in this case the size of the system is related to the number of elements used in the basis expansion of the wavefunction, we predict critical parameters in the large basis limit. Results prove to be in good agreement with previous Slater-basis set calculations and demonstrate that this combined approach provides a promising first-principles approach to describe quantum phase transitions for materials and extended systems. In the second part we look at non-equilibrium one-dimensional model known as the raise and peel model describing a growing surface which grows locally and has non-local desorption. For a specific values of adsorption ( ua) and desorption (ud) the model shows interesting features. At ua = ud, the model is described by a conformal field theory (with conformal charge c = 0) and its stationary probability can be mapped to the ground state of a quantum chain and can also be related a two dimensional statistical model. For ua ≥ ud, the model shows a scale invariant phase in the avalanche distribution. In this work we study the surface dynamics by looking at avalanche distributions using FSS formalism and explore the effect of changing the boundary conditions of the model. The model shows the same universality for the cases with and with our the wall for an odd number of tiles removed, but we find a new exponent in the presence of a wall for an even number of avalanches released. We provide new conjecture for the probability distribution of avalanches with a wall obtained by using exact diagonalization of small lattices and Monte-Carlo simulations.

User's manual for University of Arizona APART program (Analysis Program - Arizona Radiation Trace)

NASA Technical Reports Server (NTRS)

Breault, R. P.

1975-01-01

A description and operating instructions for the Analysis Program Arizona Radiation Trace (APART) are given. This is a computer program that is able to efficiently and accurately predict the off-axis rejection characteristics of unwanted stray radiation for complex rotationally symmetric optical systems. The program first determines the critical objects or areas that scatter radiation to the image plane either directly or through imaging elements: this provides the opportunity to modify, if necessary, the design so that the number of critical areas seen by the image plane is reduced or the radiation to these critical areas is minimized. Next, the power distribution reaching the image plane and a sectional power map of all internal surfaces are computed. Angular information is also provided that relates the angle by which the radiation came into a surface to the angle by which the radiation is scattered out of the surface.

Critical behavior of magnetization in URhAl: Quasi-two-dimensional Ising system with long-range interactions

NASA Astrophysics Data System (ADS)

Tateiwa, Naoyuki; Pospíšil, Jiří; Haga, Yoshinori; Yamamoto, Etsuji

2018-02-01

The critical behavior of dc magnetization in the uranium ferromagnet URhAl with the hexagonal ZrNiAl-type crystal structure has been studied around the ferromagnetic transition temperature TC. The critical exponent β for the temperature dependence of the spontaneous magnetization below TC,γ for the magnetic susceptibility, and δ for the magnetic isotherm at TC, have been obtained with a modified Arrott plot, a Kouvel-Fisher plot, the critical isotherm analysis, and the scaling analysis. We have determined the critical exponents as β =0.287 ±0.005 , γ =1.47 ±0.02 , and δ =6.08 ±0.04 by the scaling analysis and the critical isotherm analysis. These critical exponents satisfy the Widom scaling law δ =1 +γ /β . URhAl has strong uniaxial magnetic anisotropy, similar to its isostructural UCoAl that has been regarded as a three-dimensional (3D) Ising system in previous studies. However, the universality class of the critical phenomenon in URhAl does not belong to the 3D Ising model (β =0.325 , γ =1.241 , and δ =4.82 ) with short-range exchange interactions between magnetic moments. The determined exponents can be explained with the results of the renormalization group approach for a two-dimensional (2D) Ising system coupled with long-range interactions decaying as J (r ) ˜r-(d +σ ) with σ =1.44 . We suggest that the strong hybridization between the uranium 5 f and rhodium 4 d electrons in the U-RhI layer in the hexagonal crystal structure is a source of the low-dimensional magnetic property. The present result is contrary to current understandings of the physical properties in a series of isostructural UTX uranium ferromagnets (T: transition metals, X: p -block elements) based on the 3D Ising model.

Profile of Students’ Critical Thinking Skill Measured by Science Virtual Test on Living Things and Environmental Sustainability Theme

NASA Astrophysics Data System (ADS)

Maulida, N. I.; Firman, H.; Rusyati, L.

2017-02-01

The aims of this study are: (1) to investigate the level of students’ critical thinking skill on living things and environmental sustainability theme for each Inch’ critical thinking elements and overall, (2) to investigate the level of students’ critical thinking skill on living things characteristic, biodiversity, energy resources, ecosystem, environmental pollution, and global warming topics. The research was conducted due to the important of critical thinking measurement to get the current skill description as the basic consideration for further critical thinking skill improvement in lower secondary science. The research method used was descriptive. 331 seventh grade students taken from five lower secondary schools in Cirebon were tested to get the critical thinking skill data by using Science Virtual Test as the instrument. Generally, the mean scores on eight Inch’ critical thinking elements and overall score from descriptive statistic reveals a moderate attainments level. Students’ critical thinking skill on biodiversity, energy resources, ecosystem, environmental pollution, and global warming topics are in moderate level. While students’ critical thinking skill on living things characteristic is identified as high level. Students’ experience in thinking critically during science learning process and the characteristic of the topic are emerged as the reason behind the students’ critical thinking skill level on certain science topic.

Leveraging cues from person-generated health data for peer matching in online communities

PubMed Central

Hartzler, Andrea L; Taylor, Megan N; Park, Albert; Griffiths, Troy; Backonja, Uba; McDonald, David W; Wahbeh, Sam; Brown, Cory; Pratt, Wanda

2016-01-01

Objective Online health communities offer a diverse peer support base, yet users can struggle to identify suitable peer mentors as these communities grow. To facilitate mentoring connections, we designed a peer-matching system that automatically profiles and recommends peer mentors to mentees based on person-generated health data (PGHD). This study examined the profile characteristics that mentees value when choosing a peer mentor. Materials and Methods Through a mixed-methods user study, in which cancer patients and caregivers evaluated peer mentor recommendations, we examined the relative importance of four possible profile elements: health interests, language style, demographics, and sample posts. Playing the role of mentees, the study participants ranked mentors, then rated both the likelihood that they would hypothetically contact each mentor and the helpfulness of each profile element in helping the make that decision. We analyzed the participants’ ratings with linear regression and qualitatively analyzed participants’ feedback for emerging themes about choosing mentors and improving profile design. Results Of the four profile elements, only sample posts were a significant predictor for the likelihood of a mentee contacting a mentor. Communication cues embedded in posts were critical for helping the participants choose a compatible mentor. Qualitative themes offer insight into the interpersonal characteristics that mentees sought in peer mentors, including being knowledgeable, sociable, and articulate. Additionally, the participants emphasized the need for streamlined profiles that minimize the time required to choose a mentor. Conclusion Peer-matching systems in online health communities offer a promising approach for leveraging PGHD to connect patients. Our findings point to interpersonal communication cues embedded in PGHD that could prove critical for building mentoring relationships among the growing membership of online health communities. PMID:26911825

Strain-Based Damage Determination Using Finite Element Analysis for Structural Health Management

NASA Technical Reports Server (NTRS)

Hochhalter, Jacob D.; Krishnamurthy, Thiagaraja; Aguilo, Miguel A.

2016-01-01

A damage determination method is presented that relies on in-service strain sensor measurements. The method employs a gradient-based optimization procedure combined with the finite element method for solution to the forward problem. It is demonstrated that strains, measured at a limited number of sensors, can be used to accurately determine the location, size, and orientation of damage. Numerical examples are presented to demonstrate the general procedure. This work is motivated by the need to provide structural health management systems with a real-time damage characterization. The damage cases investigated herein are characteristic of point-source damage, which can attain critical size during flight. The procedure described can be used to provide prognosis tools with the current damage configuration.

Long-Term Effects of Dredging Operations Program. Long-Term Evaluation of Plants and Animals Colonizing Contaminated Estuarine Dredged Material Placed in Both Upland and Wetland Environments

DTIC Science & Technology

1991-09-01

MP D-91-5, September 1991 References Beckett, P. H. T., and Davis, R. D. 1977. Upper critical levels of toxic elements in plants. New Phytology 79:95...and ryegrass. New Phytology 80:23-42. Davis, R. D., Beckett, P. H. T., and Wollan, E. 1978. Critical levels of twenty potentially toxic elements in

Method for fabrication and verification of conjugated nanoparticle-antibody tuning elements for multiplexed electrochemical biosensors.

PubMed

La Belle, Jeffrey T; Fairchild, Aaron; Demirok, Ugur K; Verma, Aman

2013-05-15

There is a critical need for more accurate, highly sensitive and specific assay for disease diagnosis and management. A novel, multiplexed, single sensor using rapid and label free electrochemical impedance spectroscopy tuning method has been developed. The key challenges while monitoring multiple targets is frequency overlap. Here we describe the methods to circumvent the overlap, tune by use of nanoparticle (NP) and discuss the various fabrication and characterization methods to develop this technique. First sensors were fabricated using printed circuit board (PCB) technology and nickel and gold layers were electrodeposited onto the PCB sensors. An off-chip conjugation of gold NP's to molecular recognition elements (with verification technique) is described as well. A standard covalent immobilization of the molecular recognition elements is also discussed with quality control techniques. Finally use and verification of sensitivity and specificity is also presented. By use of gold NP's of various sizes, we have demonstrated the possibility and shown little loss of sensitivity and specificity in the molecular recognition of inflammatory markers as "model" targets for our tuning system. By selection of other sized NP's or NP's of various materials, the tuning effect can be further exploited. The novel platform technology developed could be utilized in critical care, clinical management and at home health and disease management. Copyright © 2013 Elsevier Inc. All rights reserved.

Impact of configuration management system of computer center on support of scientific projects throughout their lifecycle

NASA Astrophysics Data System (ADS)

Bogdanov, A. V.; Iuzhanin, N. V.; Zolotarev, V. I.; Ezhakova, T. R.

2017-12-01

In this article the problem of scientific projects support throughout their lifecycle in the computer center is considered in every aspect of support. Configuration Management system plays a connecting role in processes related to the provision and support of services of a computer center. In view of strong integration of IT infrastructure components with the use of virtualization, control of infrastructure becomes even more critical to the support of research projects, which means higher requirements for the Configuration Management system. For every aspect of research projects support, the influence of the Configuration Management system is being reviewed and development of the corresponding elements of the system is being described in the present paper.

Two Kinds of "Elements" and the Dialectic between Synthetic-deductive and Analytic-genetic Approaches in Mathematics.

ERIC Educational Resources Information Center

Steiner, Hans-Georg

1988-01-01

Describes two kinds of elements in mathematics: Euclid's and Bourbaki's. Discusses some criticisms on the two concepts of elements from a philosophical, methodological, and didactical point of view. Suggests a complementarist view and several implications for mathematics education. (YP)

A Numerical Study on the Edgewise Compression Strength of Sandwich Structures with Facesheet-Core Disbonds

NASA Technical Reports Server (NTRS)

Bergan, Andrew C.

2017-01-01

Damage tolerant design approaches require determination of critical damage modes and flaw sizes in order to establish nondestructive evaluation detection requirements. A finite element model is developed to assess the effect of circular facesheet-core disbonds on the strength of sandwich specimens subjected to edgewise compressive loads for the purpose of predicting the critical flaw size for a variety of design parameters. Postbuckling analyses are conducted in which an initial imperfection is seeded using results from a linear buckling analysis. Both the virtual crack closure technique (VCCT) and cohesive elements are considered for modeling disbond growth. Predictions from analyses using the VCCT and analyses using cohesive elements are in good correlation. A series of parametric analyses are conducted to investigate the effect of core thickness and material, facesheet layup, facesheet-core interface properties, and curvature on the criticality of facesheet-core disbonds of various sizes. The results from these analyses provide a basis for determining the critical flaw size for facesheet-core disbonds subjected to edgewise compression loads and, therefore, nondestructive evaluation flaw detection requirements for this configuration.

Systematic construction and control of stereo nerve vision network in intelligent manufacturing

NASA Astrophysics Data System (ADS)

Liu, Hua; Wang, Helong; Guo, Chunjie; Ding, Quanxin; Zhou, Liwei

2017-10-01

A system method of constructing stereo vision by using neural network is proposed, and the operation and control mechanism in actual operation are proposed. This method makes effective use of the neural network in learning and memory function, by after training with samples. Moreover, the neural network can learn the nonlinear relationship in the stereoscopic vision system and the internal and external orientation elements. These considerations are Worthy of attention, which includes limited constraints, the scientific of critical group, the operating speed and the operability in technical aspects. The results support our theoretical forecast.

NAS-current status and future plans

NASA Technical Reports Server (NTRS)

Bailey, F. R.

1987-01-01

The Numerical Aerodynamic Simulation (NAS) has met its first major milestone, the NAS Processing System Network (NPSN) Initial Operating Configuration (IOC). The program has met its goal of providing a national supercomputer facility capable of greatly enhancing the Nation's research and development efforts. Furthermore, the program is fulfilling its pathfinder role by defining and implementing a paradigm for supercomputing system environments. The IOC is only the begining and the NAS Program will aggressively continue to develop and implement emerging supercomputer, communications, storage, and software technologies to strengthen computations as a critical element in supporting the Nation's leadership role in aeronautics.

Friction-Stir Welding of Large Scale Cryogenic Fuel Tanks for Aerospace Applications

NASA Technical Reports Server (NTRS)

Jones, Clyde S., III; Venable, Richard A.

1998-01-01

The Marshall Space Flight Center has established a facility for the joining of large-scale aluminum-lithium alloy 2195 cryogenic fuel tanks using the friction-stir welding process. Longitudinal welds, approximately five meters in length, were made possible by retrofitting an existing vertical fusion weld system, designed to fabricate tank barrel sections ranging from two to ten meters in diameter. The structural design requirements of the tooling, clamping and the spindle travel system will be described in this paper. Process controls and real-time data acquisition will also be described, and were critical elements contributing to successful weld operation.

Assessment of Critical Events Corridors through Multivariate Cascading Outages Analysis

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

Makarov, Yuri V.; Samaan, Nader A.; Diao, Ruisheng

2011-10-17

Massive blackouts of electrical power systems in North America over the past decade has focused increasing attention upon ways to identify and simulate network events that may potentially lead to widespread network collapse. This paper summarizes a method to simulate power-system vulnerability to cascading failures to a supplied set of initiating events synonymously termed as Extreme Events. The implemented simulation method is currently confined to simulating steady state power-system response to a set of extreme events. The outlined method of simulation is meant to augment and provide a new insight into bulk power transmission network planning that at present remainsmore » mainly confined to maintaining power system security for single and double component outages under a number of projected future network operating conditions. Although one of the aims of this paper is to demonstrate the feasibility of simulating network vulnerability to cascading outages, a more important goal has been to determine vulnerable parts of the network that may potentially be strengthened in practice so as to mitigate system susceptibility to cascading failures. This paper proposes to demonstrate a systematic approach to analyze extreme events and identify vulnerable system elements that may be contributing to cascading outages. The hypothesis of critical events corridors is proposed to represent repeating sequential outages that can occur in the system for multiple initiating events. The new concept helps to identify system reinforcements that planners could engineer in order to 'break' the critical events sequences and therefore lessen the likelihood of cascading outages. This hypothesis has been successfully validated with a California power system model.« less

Review of Rover fuel element protective coating development at Los Alamos

NASA Technical Reports Server (NTRS)

Wallace, Terry C.

1991-01-01

The Los Alamos Scientific Laboratory (LASL) entered the nuclear propulsion field in 1955 and began work on all aspects of a nuclear propulsion program with a target exhaust temperature of about 2750 K. A very extensive chemical vapor deposition coating technology for preventing catastrophic corrosion of reactor core components by the high temperature, high pressure hydrogen propellant gas was developed. Over the 17-year term of the program, more than 50,000 fuel elements were coated and evaluated. Advances in performance were achieved only through closely coupled interaction between the developing fuel element fabrication and protective coating technologies. The endurance of fuel elements in high temperature, high pressure hydrogen environment increased from several minutes at 2000 K exit gas temperature to 2 hours at 2440 K exit gas temperature in a reactor test and 10 hours at 2350 K exit gas temperature in a hot gas test. The purpose of this paper is to highlight the rationale for selection of coating materials used (NbC and ZrC), identify critical fuel element-coat interactions that had to be modified to increase system performance, and review the evolution of protective coating technology.

Vulnerability-Based Critical Neurons, Synapses, and Pathways in the Caenorhabditis elegans Connectome

PubMed Central

Kim, Seongkyun; Kim, Hyoungkyu; Kralik, Jerald D.; Jeong, Jaeseung

2016-01-01

Determining the fundamental architectural design of complex nervous systems will lead to significant medical and technological advances. Yet it remains unclear how nervous systems evolved highly efficient networks with near optimal sharing of pathways that yet produce multiple distinct behaviors to reach the organism’s goals. To determine this, the nematode roundworm Caenorhabditis elegans is an attractive model system. Progress has been made in delineating the behavioral circuits of the C. elegans, however, many details are unclear, including the specific functions of every neuron and synapse, as well as the extent the behavioral circuits are separate and parallel versus integrative and serial. Network analysis provides a normative approach to help specify the network design. We investigated the vulnerability of the Caenorhabditis elegans connectome by performing computational experiments that (a) “attacked” 279 individual neurons and 2,990 weighted synaptic connections (composed of 6,393 chemical synapses and 890 electrical junctions) and (b) quantified the effects of each removal on global network properties that influence information processing. The analysis identified 12 critical neurons and 29 critical synapses for establishing fundamental network properties. These critical constituents were found to be control elements—i.e., those with the most influence over multiple underlying pathways. Additionally, the critical synapses formed into circuit-level pathways. These emergent pathways provide evidence for (a) the importance of backward locomotion, avoidance behavior, and social feeding behavior to the organism; (b) the potential roles of specific neurons whose functions have been unclear; and (c) both parallel and serial design elements in the connectome—i.e., specific evidence for a mixed architectural design. PMID:27540747

The contribution of nature to people: Applying concepts of values and properties to rate the management importance of natural elements.

PubMed

Smith, Michael J; Wagner, Christian; Wallace, Ken J; Pourabdollah, Amir; Lewis, Loretta

2016-06-15

An important, and yet unresolved question in natural resource management is how best to manage natural elements and their associated values to ensure human wellbeing. Specifically, there is a lack of measurement tools to assess the contribution of nature to people. We present one approach to overcome this global issue and show that the preferred state of any system element, in terms of realising human values, is a function of element properties. Consequently, natural resource managers need to understand the nature of the relationships between element properties and values if they are to successfully manage for human wellbeing. In two case studies of applied planning, we demonstrate how to identify key element properties, quantify their relationships to priority human values, and combine this information to model the contribution of elements to human wellbeing. In one of the two case studies we also compared the modelling outputs with directly elicited stakeholder opinions regarding the importance of the elements for realising the given priority values. The two, largely congruent outputs provide additional support for the approach. The study shows that rating sets of elements on their relative overall value for human wellbeing, or utility, provides critical information for subsequent management decisions and a basis for productive new research. We consider that the described approach is broadly applicable within the domain of natural resource management. Copyright © 2016 The Authors. Published by Elsevier Ltd.. All rights reserved.

Civilian Radioactive Waste Management System Requirements Document

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

C.A. Kouts

2006-05-10

The CRD addresses the requirements of Department of Energy (DOE) Order 413.3-Change 1, ''Program and Project Management for the Acquisition of Capital Assets'', by providing the Secretarial Acquisition Executive (Level 0) scope baseline and the Program-level (Level 1) technical baseline. The Secretarial Acquisition Executive approves the Office of Civilian Radioactive Waste Management's (OCRWM) critical decisions and changes against the Level 0 baseline; and in turn, the OCRWM Director approves all changes against the Level 1 baseline. This baseline establishes the top-level technical scope of the CRMWS and its three system elements, as described in section 1.3.2. The organizations responsible formore » design, development, and operation of system elements described in this document must therefore prepare subordinate project-level documents that are consistent with the CRD. Changes to requirements will be managed in accordance with established change and configuration control procedures. The CRD establishes requirements for the design, development, and operation of the CRWMS. It specifically addresses the top-level governing laws and regulations (e.g., ''Nuclear Waste Policy Act'' (NWPA), 10 Code of Federal Regulations (CFR) Part 63, 10 CFR Part 71, etc.) along with specific policy, performance requirements, interface requirements, and system architecture. The CRD shall be used as a vehicle to incorporate specific changes in technical scope or performance requirements that may have significant program implications. Such may include changes to the program mission, changes to operational capability, and high visibility stakeholder issues. The CRD uses a systems approach to: (1) identify key functions that the CRWMS must perform, (2) allocate top-level requirements derived from statutory, regulatory, and programmatic sources, and (3) define the basic elements of the system architecture and operational concept. Project-level documents address CRD requirements by further defining system element functions, decomposing requirements into significantly greater detail, and developing designs of system components, facilities, and equipment. The CRD addresses the identification and control of functional, physical, and operational boundaries between and within CRWMS elements. The CRD establishes requirements regarding key interfaces between the CRWMS and elements external to the CRWMS. Project elements define interfaces between CRWMS program elements. The Program has developed a change management process consistent with DOE Order 413.3-Change 1. Changes to the Secretarial Acquisition Executive and Program-level baselines must be approved by a Program Baseline Change Control Board. Specific thresholds have been established for identifying technical, cost, and schedule changes that require approval. The CRWMS continually evaluates system design and operational concepts to optimize performance and/or cost. The Program has developed systems analysis tools to assess potential enhancements to the physical system and to determine the impacts from cost saving initiatives, scientific and technological improvements, and engineering developments. The results of systems analyses, if appropriate, are factored into revisions to the CRD as revised Programmatic Requirements.« less

Intelligent Sensors: An Integrated Systems Approach

NASA Technical Reports Server (NTRS)

Mahajan, Ajay; Chitikeshi, Sanjeevi; Bandhil, Pavan; Utterbach, Lucas; Figueroa, Fernando

2005-01-01

The need for intelligent sensors as a critical component for Integrated System Health Management (ISHM) is fairly well recognized by now. Even the definition of what constitutes an intelligent sensor (or smart sensor) is well documented and stems from an intuitive desire to get the best quality measurement data that forms the basis of any complex health monitoring and/or management system. If the sensors, i.e. the elements closest to the measurand, are unreliable then the whole system works with a tremendous handicap. Hence, there has always been a desire to distribute intelligence down to the sensor level, and give it the ability to assess its own health thereby improving the confidence in the quality of the data at all times. This paper proposes the development of intelligent sensors as an integrated systems approach, i.e. one treats the sensors as a complete system with its own sensing hardware (the traditional sensor), A/D converters, processing and storage capabilities, software drivers, self-assessment algorithms, communication protocols and evolutionary methodologies that allow them to get better with time. Under a project being undertaken at the NASA Stennis Space Center, an integrated framework is being developed for the intelligent monitoring of smart elements. These smart elements can be sensors, actuators or other devices. The immediate application is the monitoring of the rocket test stands, but the technology should be generally applicable to the Intelligent Systems Health Monitoring (ISHM) vision. This paper outlines some fundamental issues in the development of intelligent sensors under the following two categories: Physical Intelligent Sensors (PIS) and Virtual Intelligent Sensors (VIS).

Patient- and family-centered care coordination: a framework for integrating care for children and youth across multiple systems.

PubMed

2014-05-01

Understanding a care coordination framework, its functions, and its effects on children and families is critical for patients and families themselves, as well as for pediatricians, pediatric medical subspecialists/surgical specialists, and anyone providing services to children and families. Care coordination is an essential element of a transformed American health care delivery system that emphasizes optimal quality and cost outcomes, addresses family-centered care, and calls for partnership across various settings and communities. High-quality, cost-effective health care requires that the delivery system include elements for the provision of services supporting the coordination of care across settings and professionals. This requirement of supporting coordination of care is generally true for health systems providing care for all children and youth but especially for those with special health care needs. At the foundation of an efficient and effective system of care delivery is the patient-/family-centered medical home. From its inception, the medical home has had care coordination as a core element. In general, optimal outcomes for children and youth, especially those with special health care needs, require interfacing among multiple care systems and individuals, including the following: medical, social, and behavioral professionals; the educational system; payers; medical equipment providers; home care agencies; advocacy groups; needed supportive therapies/services; and families. Coordination of care across settings permits an integration of services that is centered on the comprehensive needs of the patient and family, leading to decreased health care costs, reduction in fragmented care, and improvement in the patient/family experience of care. Copyright © 2014 by the American Academy of Pediatrics.

The Multiplicative Situation

ERIC Educational Resources Information Center

Hurst, Chris

2015-01-01

The relationships between three critical elements, and the associated mathematical language, to assist students to make the critical transition from additive to multiplicative thinking are examined in this article by Chris Hurst.

Enhanced terahertz imaging system performance analysis and design tool for concealed weapon identification

NASA Astrophysics Data System (ADS)

Murrill, Steven R.; Franck, Charmaine C.; Espinola, Richard L.; Petkie, Douglas T.; De Lucia, Frank C.; Jacobs, Eddie L.

2011-11-01

The U.S. Army Research Laboratory (ARL) and the U.S. Army Night Vision and Electronic Sensors Directorate (NVESD) have developed a terahertz-band imaging system performance model/tool for detection and identification of concealed weaponry. The details of the MATLAB-based model which accounts for the effects of all critical sensor and display components, and for the effects of atmospheric attenuation, concealment material attenuation, and active illumination, were reported on at the 2005 SPIE Europe Security & Defence Symposium (Brugge). An advanced version of the base model that accounts for both the dramatic impact that target and background orientation can have on target observability as related to specular and Lambertian reflections captured by an active-illumination-based imaging system, and for the impact of target and background thermal emission, was reported on at the 2007 SPIE Defense and Security Symposium (Orlando). This paper will provide a comprehensive review of an enhanced, user-friendly, Windows-executable, terahertz-band imaging system performance analysis and design tool that now includes additional features such as a MODTRAN-based atmospheric attenuation calculator and advanced system architecture configuration inputs that allow for straightforward performance analysis of active or passive systems based on scanning (single- or line-array detector element(s)) or staring (focal-plane-array detector elements) imaging architectures. This newly enhanced THz imaging system design tool is an extension of the advanced THz imaging system performance model that was developed under the Defense Advanced Research Project Agency's (DARPA) Terahertz Imaging Focal-Plane Technology (TIFT) program. This paper will also provide example system component (active-illumination source and detector) trade-study analyses using the new features of this user-friendly THz imaging system performance analysis and design tool.

Development of an accurate, sensitive, and robust isotope dilution laser ablation ICP-MS method for simultaneous multi-element analysis (chlorine, sulfur, and heavy metals) in coal samples.

PubMed

Boulyga, Sergei F; Heilmann, Jens; Prohaska, Thomas; Heumann, Klaus G

2007-10-01

A method for the direct multi-element determination of Cl, S, Hg, Pb, Cd, U, Br, Cr, Cu, Fe, and Zn in powdered coal samples has been developed by applying inductively coupled plasma isotope dilution mass spectrometry (ICP-IDMS) with laser-assisted introduction into the plasma. A sector-field ICP-MS with a mass resolution of 4,000 and a high-ablation rate laser ablation system provided significantly better sensitivity, detection limits, and accuracy compared to a conventional laser ablation system coupled with a quadrupole ICP-MS. The sensitivity ranges from about 590 cps for (35)Cl+ to more than 6 x 10(5) cps for (238)U+ for 1 microg of trace element per gram of coal sample. Detection limits vary from 450 ng g(-1) for chlorine and 18 ng g(-1) for sulfur to 9.5 pg g(-1) for mercury and 0.3 pg g(-1) for uranium. Analyses of minor and trace elements in four certified reference materials (BCR-180 Gas Coal, BCR-331 Steam Coal, SRM 1632c Trace Elements in Coal, SRM 1635 Trace Elements in Coal) yielded good agreement of usually not more than 5% deviation from the certified values and precisions of less than 10% relative standard deviation for most elements. Higher relative standard deviations were found for particular elements such as Hg and Cd caused by inhomogeneities due to associations of these elements within micro-inclusions in coal which was demonstrated for Hg in SRM 1635, SRM 1632c, and another standard reference material (SRM 2682b, Sulfur and Mercury in Coal). The developed LA-ICP-IDMS method with its simple sample pretreatment opens the possibility for accurate, fast, and highly sensitive determinations of environmentally critical contaminants in coal as well as of trace impurities in similar sample materials like graphite powder and activated charcoal on a routine basis.

Photovoltaic system criteria documents. Volume 4: Review criteria for photovoltaic applications

NASA Technical Reports Server (NTRS)

Koenig, John C.; Billitti, Joseph W.; Tallon, John M.

1979-01-01

Guidelines are provided for the organization, preparation and conduct of program reviews for photovoltaic applications. These criteria apply to all photovoltaic applications. They include, but are not limited to, the following: (1) Conceptual design review; (2) Preliminary design review; (3) Critical design review; and (4) Operational readiness review. Contract goal's and objectives are met through program monitoring for cost, schedule, and performance for both managerial and technical elements for all PV applications activities.

Power-Conversion Concept Designed for the Jupiter Icy Moons Orbiter

NASA Technical Reports Server (NTRS)

Mason, Lee S.

2004-01-01

The Jupiter Icy Moons Orbiter (JIMO) is a bold new mission being developed by NASA's Office of Space Science under Project Prometheus. JIMO is examining the potential of nuclear electric propulsion (NEP) technology to efficiently deliver scientific payloads to three of Jupiter's moons: Callisto, Ganymede, and Europa. A critical element of the NEP spacecraft is the space reactor power system (SRPS), consisting of the nuclear reactor, power conversion, heat rejection, and power management and distribution (PMAD).

Thematic mapper critical elements breadboard program

NASA Technical Reports Server (NTRS)

Dale, C. H., Jr.; Engel, J. L.; Harney, E. D.

1976-01-01

A 40.6 cm bidirectional scan mirror assembly, a scan line corrector and a silicon photodiode array with integral preamplifier input stages were designed, fabricated, and tested to demonstrate performance consistent with requirements of the Hughes thematic mapper system. The measured performance met or exceeded the original design goals in all cases with the qualification that well defined and well understood deficiencies in the design of the photodiode array package will require the prescribed corrections before flight use.

Business Sector Development: A Critical Component of an Operational Approach to Stability Operations

DTIC Science & Technology

2010-11-30

CONTRACT NUMBER 5b. GRANT NUMBER 5c. PROGRAM ELEMENT NUMBER 6. AUTHOR (S) Major Travis J. Lindberg, United States Army 5d. PROJECT... nature of the local free-market system, to include the much-heralded National Solidarity Programme, will inevitably produce benefits whose costs are... author , and do not represent the views of the US Army School of Advanced Military Studies, the US Army Command and General Staff College, the United

Critical evaluation and thermodynamic optimization of the Iron-Rare-Earth systems

NASA Astrophysics Data System (ADS)

Konar, Bikram

Rare-Earth elements by virtue of its typical magnetic, electronic and chemical properties are gaining importance in power, electronics, telecommunications and sustainable green technology related industries. The Magnets from RE-alloys are more powerful than conventional magnets which have more longevity and high temperature workability. The dis-equilibrium in the Rare-Earth element supply and demand has increased the importance of recycling and extraction of REE's from used permanent Magnets. However, lack of the thermodynamic data on RE alloys has made it difficult to design an effective extraction and recycling process. In this regard, Computational Thermodynamic calculations can serve as a cost effective and less time consuming tool to design a waste magnet recycling process. The most common RE permanent magnet is Nd magnet (Nd 2Fe14B). Various elements such as Dy, Tb, Pr, Cu, Co, Ni, etc. are also added to increase its magnetic and mechanical properties. In order to perform reliable thermodynamic calculations for the RE recycling process, accurate thermodynamic database for RE and related alloys are required. The thermodynamic database can be developed using the so-called CALPHAD method. The database development based on the CALPHAD method is essentially the critical evaluation and optimization of all available thermodynamic and phase diagram data. As a results, one set of self-consistent thermodynamic functions for all phases in the given system can be obtained, which can reproduce all reliable thermodynamic and phase diagram data. The database containing the optimized Gibbs energy functions can be used to calculate complex chemical reactions for any high temperature processes. Typically a Gibbs energy minimization routine, such as in FactSage software, can be used to obtain the accurate thermodynamic equilibrium in multicomponent systems. As part of a large thermodynamic database development for permanent magnet recycling and Mg alloy design, all thermodynamic and phase diagram data in the literature for the fourteen Fe-RE binary systems: Fe-La, Fe-Ce, Fe-Pr, Fe-Nd, Fe-Sm, Fe-Gd, Fe-Tb, Fe-Dy, Fe-Ho, Fe-Er, Fe-Tm, Fe-Lu, Fe-Sc and Fe-Y are critically evaluated and optimized to obtain thermodynamic model parameters. The model parameters can be used to calculate phase diagrams and Gibbs energies of all phases as functions of temperature and composition. This database can be incorporated with the present thermodynamic database in FactSage software to perform complex chemical reactions and phase diagram calculations for RE magnet recycling process.

Concepts and Benefits of Lunar Core Drilling

NASA Technical Reports Server (NTRS)

McNamara, K. M.; Bogard, D. D.; Derkowski, B. J.; George, J. A.; Askew, R. S.; Lindsay, J. F.

2007-01-01

Understanding lunar material at depth is critical to nearly every aspect of NASA s Vision and Strategic Plan. As we consider sending human s back to the Moon for brief and extended periods, we will need to utilize lunar materials in construction, for resource extraction, and for radiation shielding and protection. In each case, we will be working with materials at some depth beneath the surface. Understanding the properties of that material is critical, thus the need for Lunar core drilling capability. Of course, the science benefit from returning core samples and operating down-hole autonomous experiments is a key element of Lunar missions as defined by NASA s Exploration Systems Architecture Study. Lunar missions will be targeted to answer specific questions concerning lunar science and re-sources.

Images of health insurance in popular film: the dissolving critique.

PubMed

Pendo, Elizabeth A

2004-01-01

Several recent films have villainized the health-insurance industry as a central element of their plots. This Article examines three of those films: Critical Care, The Rainmaker, and John Q. It analyzes these films through the context of the consumer backlash against managed care that began in the 1990s and shows how these films reflect the consumer sentiment regarding health-insurance companies and the cost controlling strategies they employ. In addition, the Article identifies three key premises about health insurance in the films that, although exaggerated and incomplete, have significant factual support. Ultimately, the author argues that, despite their passionately critical and liberal tone, these films actually put forward solutions that are highly individualist and conservative, rather than inclusive and systemic.

A Critical Review of High Entropy Alloys and Related Concepts (Postprint)

DTIC Science & Technology

2016-10-21

448e511 451The purpose of this paper is to critically assess the major ideas and proposed characteristics of high entropy and multi-principal element...re-introduced once again to put the modern HEA and MPEA concepts into his- torical perspective [17]. A second paper of historical note applied the...MPEA concept to metallic glasses [19]. This paper used equi- molar substitution of chemically similar elements in a known metallic glass alloy. This is

Diffraction as a Method of Critical Policy Analysis

ERIC Educational Resources Information Center

Ulmer, Jasmine B.

2016-01-01

Recent developments in critical policy analysis have occurred alongside the new materialisms in qualitative research. These lines of scholarship have unfolded along two separate, but related, tracks. In particular, the new materialist method of "diffraction" aligns with many elements of critical policy analysis. Both involve critical…

Adapting Entry-Level Engineering Courses to Emphasize Critical Thinking

ERIC Educational Resources Information Center

Hagerty, D. Joseph; Rockaway, Thomas D.

2012-01-01

The University of Louisville recently developed a Quality Enhancement Plan (QEP) to improve undergraduate instruction across all disciplines as part of its ongoing accreditation requirements. Central elements of the plan are emphasis on critical thinking; integration of critical thinking throughout the curriculum; service learning for…

A Status of the Advanced Space Transportation Program from Planning to Action

NASA Technical Reports Server (NTRS)

Lyles, Garry; Griner, Carolyn

1998-01-01

A Technology Plan for Enabling Commercial Space Business was presented at the 48th International Astronautical Congress in Turin, Italy. This paper presents a status of the program's accomplishments. Technology demonstrations have progressed in each of the four elements of the program; (1) Low Cost Technology, (2) Advanced Reusable Technology, (3) Space Transfer Technology and (4) Space Transportation Research. The Low Cost Technology program element is primarily focused at reducing development and acquisition costs of aerospace hardware using a "design to cost" philosophy with robust margins, adapting commercial manufacturing processes and commercial off-the-shelf hardware. The attributes of this philosophy for small payload launch are being demonstrated at the component, sub-system, and system level. The X-34 "Fastrac" engine has progressed through major component and subsystem demonstrations. A propulsion system test bed has been implemented for system-level demonstration of component and subsystem technologies; including propellant tankage and feedlines, controls, pressurization, and engine systems. Low cost turbopump designs, commercial valves and a controller are demonstrating the potential for a ten-fold reduction in engine and propulsion system costs. The Advanced Reusable Technology program element is focused on increasing life through high strength-to-weight structures and propulsion components, highly integrated propellant tanks, automated checkout and health management and increased propulsion system performance. The validation of rocket based combined cycle (RBCC) propulsion is pro,-,ressing through component and subsystem testing. RBCC propulsion has the potential to provide performance margin over an all rocket system that could result in lower gross liftoff weight, a lower propellant mass fraction or a higher payload mass fraction. The Space Transfer Technology element of the program is pursuing technology that can improve performance and dramatically reduce the propellant and structural mass of orbit transfer and deep space systems. Flight demonstration of ion propulsion is progressing towards launch. Ion propulsion is the primary propulsion for Deep Space 1; a flyby of comet West-kohoutek-lkemura and asteroid 3352 McAuliffe. Testing of critical solar-thermal propulsion subsystems have been accomplished and planning is continuing for the flight demonstration of an electrodynamic tether orbit transfer system. The forth and final element of the program, Space Transportation Research, has progressed in several areas of propulsion research. This element of the program is focused at long-term (25 years) breakthrough concepts that could bring launch costs to a factor of one hundred below today's cost or dramatically expand planetary travel and enable interstellar travel.

Infiltration behaviour of elemental mercury DNAPL in fully and partially water saturated porous media.

PubMed

D'Aniello, Andrea; Hartog, Niels; Sweijen, Thomas; Pianese, Domenico

2018-02-01

Mercury is a contaminant of global concern due to its harmful effects on human health and for the detrimental consequences of its release in the environment. Sources of liquid elemental mercury are usually anthropogenic, such as chlor-alkali plants. To date insight into the infiltration behaviour of liquid elemental mercury in the subsurface is lacking, although this is critical for assessing both characterization and remediation approaches for mercury DNAPL contaminated sites. Therefore, in this study the infiltration behaviour of elemental mercury in fully and partially water saturated systems was investigated using column experiments. The properties affecting the constitutive relations governing the infiltration behaviour of liquid Hg 0 , and PCE for comparison, were determined using P c (S) experiments with different granular porous media (glass beads and sands) for different two- and three-phase configurations. Results showed that, in water saturated porous media, elemental mercury, as PCE, acted as a non-wetting fluid. The required entry head for elemental mercury was higher (from about 5 to 7 times). However, due to the almost tenfold higher density of mercury, the required NAPL entry heads of 6.19cm and 12.51cm for mercury to infiltrate were 37.5% to 20.7% lower than for PCE for the same porous media. Although Leverett scaling was able to reproduce the natural tendency of Hg 0 to be more prone than PCE to infiltrate in water saturated porous media, it considerably underestimated Hg 0 infiltration capacity in comparison with the experimental results. In the partially water saturated system, in contrast with PCE, elemental mercury also acted as a nonwetting fluid, therefore having to overcome an entry head to infiltrate. The required Hg 0 entry heads (10.45 and 15.74cm) were considerably higher (68.9% and 25.8%) than for the water saturated porous systems. Furthermore, in the partially water saturated systems, experiments showed that elemental mercury displaced both air and water, depending on the initial water distribution within the pores. This indicates that the conventional wettability hierarchy, in which the NAPL has an intermediate wetting state between the air and the water phases, is not valid for liquid elemental mercury. Therefore, for future modelling of elemental mercury DNAPL infiltration behaviour in variably water saturated porous media, a different formulation of the governing constitutive relations will be required. Copyright © 2018 Elsevier B.V. All rights reserved.

The Development and Implementation of Cognitive Aids for Critical Events in Pediatric Anesthesia: The Society for Pediatric Anesthesia Critical Events Checklists.

PubMed

Clebone, Anna; Burian, Barbara K; Watkins, Scott C; Gálvez, Jorge A; Lockman, Justin L; Heitmiller, Eugenie S

2017-03-01

Cognitive aids such as checklists are commonly used in modern operating rooms for routine processes, and the use of such aids may be even more important during critical events. The Quality and Safety Committee of the Society for Pediatric Anesthesia (SPA) has developed a set of critical-event checklists and cognitive aids designed for 3 purposes: (1) as a repository of the latest evidence-based and expert opinion-based information to guide response and management of critical events, (2) as a source of just-in-time information during critical events, and (3) as a method to facilitate a shared understanding of required actions among team members during a critical event. Committee members, who represented children's hospitals from across the nation, used the recent literature and established guidelines (where available) and incorporated the expertise of colleagues at their institutions to develop these checklists, which included relevant factors to consider and steps to take in response to critical events. Human factors principles were incorporated to enhance checklist usability, facilitate error-free accomplishment, and ensure a common approach to checklist layout, formatting, structure, and design.The checklists were made available in multiple formats: a PDF version for easy printing, a mobile application, and at some institutions, a Web-based application using the anesthesia information management system. After the checklists were created, training commenced, and plans for validation were begun. User training is essential for successful implementation and should ideally include explanation of the organization of the checklists; familiarization of users with the layout, structure, and formatting of the checklists; coaching in how to use the checklists in a team environment; reviewing of the items; and simulation of checklist use. Because of the rare and unpredictable nature of critical events, clinical trials that use crisis checklists are difficult to conduct; however, recent and future simulation studies with adult checklists provide a promising avenue for future validation of the SPA checklists. This article will review the developmental steps in producing the SPA crisis checklists, including creation of content, incorporation of human factors elements, and validation in simulation. Critical-events checklists have the potential to improve patient care during emergency events, and it is hoped that incorporating the elements presented in this article will aid in successful implementation of these essential cognitive aids.

Prediction of shear critical behavior of high-strength reinforced concrete columns using finite element methods

NASA Astrophysics Data System (ADS)

Alrasyid, Harun; Safi, Fahrudin; Iranata, Data; Chen-Ou, Yu

2017-11-01

This research shows the prediction of shear behavior of High-Strength Reinforced Concrete Columns using Finite-Element Method. The experimental data of nine half scale high-strength reinforced concrete were selected. These columns using specified concrete compressive strength of 70 MPa, specified yield strength of longitudinal and transverse reinforcement of 685 and 785 MPa, respectively. The VecTor2 finite element software was used to simulate the shear critical behavior of these columns. The combination axial compression load and monotonic loading were applied at this prediction. It is demonstrated that VecTor2 finite element software provides accurate prediction of load-deflection up to peak at applied load, but provide similar behavior at post peak load. The shear strength prediction provide by VecTor 2 are slightly conservative compare to test result.

Biospheres and solar system exploration

NASA Technical Reports Server (NTRS)

Paine, Thomas O.

1990-01-01

The implications of biosphere technology is briefly examined. The exploration status and prospects of each world in the solar system is briefly reviewed, including the asteroid belt, the moon, and comets. Five program elements are listed as particularly critical for future interplanetary operations during the coming extraterrestrial century. They include the following: (1) a highway to Space (earth orbits); (2) Orbital Spaceports to support spacecraft assembly, storage, repair, maintenance, refueling, launch, and recovery; (3) a Bridge Between Worlds to transport cargo and crews to the moon and beyond to Mars; (4) Prospecting and Resource Utilization Systems to map and characterize the resources of planets, moons, and asteroids; and (5) Closed Ecology Biospheres. The progress in these five field is reviewed.

The Opportunity in Commercial Approaches for Future NASA Deep Space Exploration Elements

NASA Technical Reports Server (NTRS)

Zapata, Edgar

2017-01-01

In 2011, NASA released a report assessing the market for commercial crew and cargo services to low Earth orbit (LEO). The report stated that NASA had spent a few hundred million dollars in the Commercial Orbital Transportation Services (COTS) program on the portion related to the development of the Falcon 9 launch vehicle. Yet a NASA cost model predicted the cost would have been significantly more with a non-commercial cost-plus contracting approach. By 2016 a NASA request for information stated it must "maximize the efficiency and sustainability of the Exploration Systems development programs", as "critical to free resources for reinvestment...such as other required deep space exploration capabilities." This work joins the previous two events, showing the potential for commercial, public private partnerships, modeled on programs like COTS, to reduce the cost to NASA significantly for "...other required deep space exploration capabilities." These other capabilities include landers, stages and more. We mature the concept of "costed baseball cards", adding cost estimates to NASA's space systems "baseball cards." We show some potential costs, including analysis, the basis of estimates, data sources and caveats to address a critical question - based on initial assessment, are significant agency resources justified for more detailed analysis and due diligence to understand and invest in public private partnerships for human deep space exploration systems? The cost analysis spans commercial to cost-plus contracting approaches, for smaller elements vs. larger, with some variation for lunar or Mars. By extension, we delve briefly into the potentially much broader significance of the individual cost estimates if taken together as a NASA investment portfolio where public private partnership are stitched together for deep space exploration. How might multiple improvements in individual systems add up to NASA human deep space exploration achievements, realistically, affordably, sustainably, in a relevant timeframe?

Applications of the DOE/NASA wind turbine engineering information system

NASA Technical Reports Server (NTRS)

Neustadter, H. E.; Spera, D. A.

1981-01-01

A statistical analysis of data obtained from the Technology and Engineering Information Systems was made. The systems analyzed consist of the following elements: (1) sensors which measure critical parameters (e.g., wind speed and direction, output power, blade loads and component vibrations); (2) remote multiplexing units (RMUs) on each wind turbine which frequency-modulate, multiplex and transmit sensor outputs; (3) on-site instrumentation to record, process and display the sensor output; and (4) statistical analysis of data. Two examples of the capabilities of these systems are presented. The first illustrates the standardized format for application of statistical analysis to each directly measured parameter. The second shows the use of a model to estimate the variability of the rotor thrust loading, which is a derived parameter.

Advancement of Optical Component Control for an Imaging Fabry-Perot Interferometer

NASA Technical Reports Server (NTRS)

Larar, Allen M.; Cook, William B.; Flood, Michael A.; Campbell, Joel F.; Boyer, Charles M.

2009-01-01

Risk mitigation activities associated with a prototype imaging Fabry-Perot Interferometer (FPI) system are continuing at the NASA Langley Research Center. The system concept and technology center about enabling and improving future space-based atmospheric composition missions, with a current focus on observing tropospheric ozone around 9.6 micron, while having applicability toward measurement in different spectral regions and other applications. Recent activities have focused on improving an optical element control subsystem to enable precise and accurate positioning and control of etalon plates; this is needed to provide high system spectral fidelity critical for enabling the required ability to spectrally-resolve atmospheric line structure. The latest results pertaining to methodology enhancements, system implementation, and laboratory characterization testing will be reported

A Solution Space for a System of Null-State Partial Differential Equations: Part 4

NASA Astrophysics Data System (ADS)

Flores, Steven M.; Kleban, Peter

2015-01-01

This article is the last of four that completely and rigorously characterize a solution space for a homogeneous system of 2 N + 3 linear partial differential equations in 2 N variables that arises in conformal field theory (CFT) and multiple Schramm-Löwner evolution (SLE). The system comprises 2 N null-state equations and three conformal Ward identities that govern CFT correlation functions of 2 N one-leg boundary operators. In the first two articles (Flores and Kleban in Commun Math Phys, 2012; Flores and Kleban, in Commun Math Phys, 2014), we use methods of analysis and linear algebra to prove that dim , with C N the Nth Catalan number. Using these results in the third article (Flores and Kleban, in Commun Math Phys, 2013), we prove that dim and is spanned by (real-valued) solutions constructed with the Coulomb gas (contour integral) formalism of CFT. In this article, we use these results to prove some facts concerning the solution space . First, we show that each of its elements equals a sum of at most two distinct Frobenius series in powers of the difference between two adjacent points (unless is odd, in which case a logarithmic term may appear). This establishes an important element in the operator product expansion for one-leg boundary operators, assumed in CFT. We also identify particular elements of , which we call connectivity weights, and exploit their special properties to conjecture a formula for the probability that the curves of a multiple-SLE process join in a particular connectivity. This leads to new formulas for crossing probabilities of critical lattice models inside polygons with a free/fixed side-alternating boundary condition, which we derive in Flores et al. (Partition functions and crossing probabilities for critical systems inside polygons, in preparation). Finally, we propose a reason for why the exceptional speeds [certain values that appeared in the analysis of the Coulomb gas solutions in Flores and Kleban (Commun Math Phys, 2013)] and the minimal models of CFT are connected.

Cold Aero Performance of a Two-Dimensional Mixer Ejector Nozzle

NASA Technical Reports Server (NTRS)

Balan, C.

2005-01-01

Since 1986, NASA and the U.S. aerospace industry have been assessing the economic viability and environmental acceptability of a second-generation supersonic civil transport, or High Speed Civil Transport (HSCT). Environmental acceptability in terms of airport community noise and economic viability are critical elements in this endeavor. Development of a propulsion system that satisfies strict airport noise regulations (FAR36 Stage III levels), at acceptable performance and weight, is critical to the success of any HSCT program. Two-dimensional mixer-ejector (2DME) exhaust systems are one approach in achieving this goal. In support of HSCT development, GEAE (GE Aircraft Engines), under contract to the NASA Glenn Research Center, conducted this test program at the NASA Langley 16 ft transonic wind tunnel to evaluate the cold aerodynamic performance aspects of the 2DME exhaust system concept. The effects of SAR (SAR, suppressor area ratio, = mixed-flow area/primary nozzle throat area), MAR (MAR = overall exhaust system exit/mixing-plane area), flap length, CER (suppressor chute expansion ratio), chute alignment, and free stream Mach number were investigated on a 1/11th cold aerodynamic scale model of a 2DME exhaust system.

Study of magnetization switching in coupled magnetic nanostructured systems

NASA Astrophysics Data System (ADS)

Radu, Cosmin

A study of magnetization dynamics experiments in nanostructured materials using the rf susceptibility tunnel diode oscillator (TDO) method is presented along with a extensive theoretical analysis. An original, computer controlled experimental setup that measures the change in susceptibility with the variation in external magnetic field and sample temperature was constructed. The TDO-based experiment design and construction is explained in detail, showing all the elements of originality. This experimental technique has proven reliable for characterizing samples with uncoupled magnetic structure and various magnetic anisotropies like: CrO2, FeCo/IrMn and Co/SiO2 thin films. The TDO was subsequently used to explore the magnetization switching in coupled magnetic systems, like synthetic antiferromagnet (SAF) structures. Magnetoresistive random access memory (MRAM) is an important example of devices where the use of SAF structure is essential. To support the understanding of the SAF magnetic behavior, its configuration and application are reviewed and more details are provided in an appendix. Current problems in increasing the scalability and decreasing the error rate of MRAM devices are closely connected to the switching properties of the SAF structures. Several theoretical studies that were devoted to the understanding of the concepts of SAF critical curve are reviewed. As one can notice, there was no experimental determination of SAF critical curve, due to the difficulties in characterizing a magnetic coupled structure. Depending of the coupling strength between the two ferromagnetic layers, on the SAF critical curve one distinguishes several new features, inexistent in the case of uncoupled systems. Knowing the configuration of the SAF critical curve is of great importance in order to control its switching characteristics. For the first time a method of experimentally recording the critical curve for SAF is proposed in this work. In order to overcome technological limitations, a new way of recording the critical curve by using an additional magnetic bias field was explored. Keywords: magnetization dynamics, magnetic susceptibility, tunnel diode oscillator, critical curve, synthetic antiferromagnet, coupled magnetic structures, MRAM.

Optimizing the way kinematical feed chains with great distance between slides are chosen for CNC machine tools

NASA Astrophysics Data System (ADS)

Lucian, P.; Gheorghe, S.

2017-08-01

This paper presents a new method, based on FRISCO formula, for optimizing the choice of the best control system for kinematical feed chains with great distance between slides used in computer numerical controlled machine tools. Such machines are usually, but not limited to, used for machining large and complex parts (mostly in the aviation industry) or complex casting molds. For such machine tools the kinematic feed chains are arranged in a dual-parallel drive structure that allows the mobile element to be moved by the two kinematical branches and their related control systems. Such an arrangement allows for high speed and high rigidity (a critical requirement for precision machining) during the machining process. A significant issue for such an arrangement it’s the ability of the two parallel control systems to follow the same trajectory accurately in order to address this issue it is necessary to achieve synchronous motion control for the two kinematical branches ensuring that the correct perpendicular position it’s kept by the mobile element during its motion on the two slides.

Emerging Frontiers of Neuroengineering: A Network Science of Brain Connectivity

PubMed Central

Bassett, Danielle S.; Khambhati, Ankit N.; Grafton, Scott T.

2018-01-01

Neuroengineering is faced with unique challenges in repairing or replacing complex neural systems that are composed of many interacting parts. These interactions form intricate patterns over large spatiotemporal scales and produce emergent behaviors that are difficult to predict from individual elements. Network science provides a particularly appropriate framework in which to study and intervene in such systems by treating neural elements (cells, volumes) as nodes in a graph and neural interactions (synapses, white matter tracts) as edges in that graph. Here, we review the emerging discipline of network neuroscience, which uses and develops tools from graph theory to better understand and manipulate neural systems from micro- to macroscales. We present examples of how human brain imaging data are being modeled with network analysis and underscore potential pitfalls. We then highlight current computational and theoretical frontiers and emphasize their utility in informing diagnosis and monitoring, brain–machine interfaces, and brain stimulation. A flexible and rapidly evolving enterprise, network neuroscience provides a set of powerful approaches and fundamental insights that are critical for the neuroengineer’s tool kit. PMID:28375650

Fostering Critical Thinking in the Classroom

ERIC Educational Resources Information Center

Sahamid, Husniah

2014-01-01

The ability to cite reasons, to justify claims and give support to arguments is seen as primary characteristics of a critical thinker. This paper discusses how the "Elements of Reasoning" is employed with Socratic Questioning to develop critical thinking in the language classroom. The principles that guide the questioning are laid out…

Active Student Involvement Focusing on Critical Analysis of Commercial Television.

ERIC Educational Resources Information Center

Notar, Ellen E.; Robinson, Rhonda S.

This paper examines classroom techniques for stimulating students' critical faculties in viewing commercial television. The thrust is not only to increase critical viewing judgments, but also to heighten their knowledge of the literary elements of television. Television literacy may be developed by attention to the artistry of the television…

Program Development for Primary School Teachers' Critical Thinking

ERIC Educational Resources Information Center

Boonjeam, Waraporn; Tesaputa, Kowat; Sri-ampai, Anan

2017-01-01

The objectives of this research were: 1) to study the elements and indicators of primary school teachers' critical thinking, 2) to study current situation, desirable situation, development technique, and need for developing the primary school teachers' critical thinking, 3) to develop the program for developing the primary school teachers'…

Effects of Critical Thinking Intervention for Early Childhood Teacher Candidates

ERIC Educational Resources Information Center

Han, Heejeong Sophia; Brown, E. Todd

2013-01-01

This study is based on an intervention designed to enhance early childhood teacher candidates' critical thinking abilities. The concept, elements, standards, and traits of critical thinking were integrated into the main course contents, and the effects of the intervention were examined. The results indicated that early childhood teacher…

Negotiating Democratic Relations in a Doctoral Project Examining University Conditions and Pedagogical Praxis

ERIC Educational Resources Information Center

Mahon, Kathleen

2017-01-01

This article is a critically reflexive account of how collaborative processes and democratic relations were negotiated in a doctoral research project which combined elements of institutional ethnography, self-study, and, significantly for this article, critical participatory action research. The critical participatory action research dimension of…

On the roles of repetitive DNA elements in the context of a unified genomic-epigenetic system.

PubMed

von Sternberg, Richard

2002-12-01

Repetitive DNA sequences comprise a substantial portion of most eukaryotic and some prokaryotic chromosomes. Despite nearly forty years of research, the functions of various sequence families as a whole and their monomer units remain largely unknown. The inability to map specific functional roles onto many repetitive DNA elements (REs), coupled with the taxon-specificity of sequence families, have led many to speculate that these genomic components are "selfish" replicators generating genomic "junk." The purpose of this paper is to critically examine the selfishness, evolutionary effects, and functionality of REs. First, a brief overview of the range of ideas pertaining to RE function is presented. Second, the argument is presented that the selfish DNA "hypothesis" is actually a narrative scheme, that it serves to protect neo-Darwinian assumptions from criticism, and that this story is untestable and therefore not a hypothesis. Third, attempts to synthesize the selfish DNA concept with complex systems models of the genome and RE functionality are critiqued. Fourth, the supposed connection between RE-induced mutations and macroevolutionary events are stated to be at variance with empirical evidence and theoretical considerations. Hypotheses that base phylogenetic transitions in repetitive sequence changes thus remain speculative. Fifth and finally, the case is made for viewing REs as integrally functional components of chromosomes, genomes, and cells. It is argued throughout that a new conceptual framework is needed for understanding the roles of repetitive DNA in genomic/epigenetic systems, and that neo-Darwinian "narratives" have been the primary obstacle to elucidating the effects of these enigmatic components of chromosomes.

Considerations on the performance and fabrication of candidate materials for the Yucca Mountain repository waste packages highly corrosion resistant nickel-base and titanium-base alloys

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

Dalder, E; Goldberg, A

1995-11-30

Among the metallurgical factors that affect the performance of a material in a given environment are alloy composition, alloy segregation, depletion of alloying elements, non-uniform microstructures, precipitation leading to an increase in susceptibility to corrosion as well as decreases in ductility, residual plastic deformation, and residual stresses. Precipitation often occurs preferentially at grain boundaries, causing depletion of critical elements in regions adjacent to these boundaries. Continuous grain-boundary precipitates can lead to drops in ductility and toughness. The presence of non-metallic inclusions, if excessive and/or segregated, can also cause embrittlement. Segregation of alloying elements can result in localized galvanic action. Depletionmore » of alloying elements as well as segregation can result in reductions in the concentrations of critical elements below those necessary to resist localized corrosion. Segregation and alloy depletion can also facilitate precipitation that could lead to embrittlement.« less

New alloys to conserve critical elements. [replacing chromium in steels

NASA Technical Reports Server (NTRS)

Stephens, J. R.

1978-01-01

Previous studies and surveys on availability of domestic reserves have shown that chromium is a most critical element within the U.S. metal industry. More precisely, the bulk of chromium is consumed in the production of stainless steels, specifically Type 304 stainless steel (304SS) which contains 18% Cr. The present paper deals with means of reducing chromium in commercial stainless steels by substituting more abundant or less expensive elements with the intent of maintaining the properties of 304SS. The discussion focuses on some of the oxidation and corrosion properties of new substitute stainless steels with only 12% Cr, which represents a potential saving of 33% of the chromium consumed in the production of 304SS. The alloying elements substituted for Cr in 304SS are selected according to their potential for protective oxide formation during high-temperature oxidation; these are Al, Si, Ti, Y, and misch metal which is 99.7% rare-earth metals containing 50 to 55% cerium. Other alloying elements to impart corrosion resistance are Mn, Mo, and V.

Nickel-hydrogen separator development

NASA Technical Reports Server (NTRS)

Gonzalez-Sanabria, O. D.

1986-01-01

The separator technology is a critical element in the nickel-hydrogen (Ni-H2) systems. Previous research and development work carried out at NASA Lewis Research Center has determined that separators made from zirconium oxide (ZrO2) and potassium titanate (PKT) fibers will function satisfactorily in Ni-H2 cells without exhibiting the problems associated with the asbestos separators. A program has been established to transfer the separator technology into a commercial production line. A detailed plan of this program will be presented and the preliminary results will be discussed.

Probabilistic Structural Analysis Methods for select space propulsion system components (PSAM). Volume 3: Literature surveys and technical reports

NASA Technical Reports Server (NTRS)

1992-01-01

The technical effort and computer code developed during the first year are summarized. Several formulations for Probabilistic Finite Element Analysis (PFEA) are described with emphasis on the selected formulation. The strategies being implemented in the first-version computer code to perform linear, elastic PFEA is described. The results of a series of select Space Shuttle Main Engine (SSME) component surveys are presented. These results identify the critical components and provide the information necessary for probabilistic structural analysis.

[Quality control in herbal supplements].

PubMed

Oelker, Luisa

2005-01-01

Quality and safety of food and herbal supplements are the result of a whole of different elements as good manufacturing practice and process control. The process control must be active and able to individuate and correct all possible hazards. The main and most utilized instrument is the hazard analysis critical control point (HACCP) system the correct application of which can guarantee the safety of the product. Herbal supplements need, in addition to standard quality control, a set of checks to assure the harmlessness and safety of the plants used.

Comparison of the Frequency Response and Voltage Tuning Characteristics of a FFP and a MEMS Fiber Optic Tunable Filter

DTIC Science & Technology

2004-05-12

Structural Engineering, La Jolla, CA 92093 14. ABSTRACT Tunable optical filters based on a Fabry - Perot element are a critical component in many...wavelength based fiber optic sensor systems. This report compares the performance of two fiber-pigtailed tunable optical filters, the fiber Fabry - Perot (FFP...both filters suggests that they can operate at frequencies up to 20 kHz and possibly as high as 100 kHz. 15. SUBJECT TERMS Tunable Fabry - Perot filters

Micro-XRF : Elemental Analysis for In Situ Geology and Astrobiology Exploration

NASA Technical Reports Server (NTRS)

Allwood, Abigail; Hodyss, Robert; Wade, Lawrence

2012-01-01

The ability to make close-up measurements of rock chemistry is one of the most fundamental tools for astrobiological exploration of Mars and other rocky bodies of the solar system. When conducting surface-based exploration, lithochemical measurements provide critical data that enable interpretation of the local geology, which in turn is vital for determining habitability and searching for evidence of life. The value of lithochemical measurements for geological interpretations has been repeatedly demonstrated with virtually every landed Mars mission over the past four decades.

[Social control and information democratization: a process under construction].

PubMed

Assis, Marluce Maria Araújo; Villa, Tereza Cristina Scatena

2003-01-01

This work aims at a critical reflection on social control as a legal-institutional achievement and its legitimacy conditions, pointing out strategies for information democratization in the local health system. The text was developed according to three thematic units: the first discusses social participation as a legal-institutional achievement; the second analyzes the essential conditions for legitimacy and the third presents information as a fundamental element for management and social control as an unfinished process that is still under construction.

Software Assurance in Acquisition: Mitigating Risks to the Enterprise. A Reference Guide for Security-Enhanced Software Acquisition and Outsourcing

DTIC Science & Technology

2009-02-01

management, available at <http://www.iso.org/ iso /en/CatalogueDetailPage.CatalogueDetail?CSNUMBER=39612&ICS1=35&ICS2=40 &ICS3=>. ISO /IEC 27001 . Information...Management of the Systems Engineering Process. [ ISO /IEC 27001 ] ISO /IEC 27001 :2005. Information technology -- Security techniques -- Information security...software life cycles [ ISO /IEC 15026]. Software assurance is a key element of national security and homeland security. It is critical because dramatic

Critical early mission design considerations for lunar data systems architecture

NASA Technical Reports Server (NTRS)

Hei, Donald J., Jr.; Stephens, Elaine

1992-01-01

This paper outlines recent early mission design activites for a lunar data systems architecture. Each major functional element is shown to be strikingly similar when viewed in a common reference system. While this similarity probably deviates with lower levels of decomposition, the sub-functions can always be arranged into similar and dissimilar categories. Similar functions can be implemented as objects - implemented once and reused several times like today's advanced integrated circuits. This approach to mission data systems, applied to other NASA programs, may result in substantial agency implementation and maintenance savings. In today's zero-sum-game budgetary environment, this approach could help to enable a lunar exploration program in the next decade. Several early mission studies leading to such an object-oriented data systems design are recommended.

Building Construction Progress Monitoring Using Unmanned Aerial System (uas), Low-Cost Photogrammetry, and Geographic Information System (gis)

NASA Astrophysics Data System (ADS)

Bognot, J. R.; Candido, C. G.; Blanco, A. C.; Montelibano, J. R. Y.

2018-05-01

Monitoring the progress of building's construction is critical in construction management. However, measuring the building construction's progress are still manual, time consuming, error prone, and impose tedious process of analysis leading to delays, additional costings and effort. The main goal of this research is to develop a methodology for building construction progress monitoring based on 3D as-built model of the building from unmanned aerial system (UAS) images, 4D as-planned model (with construction schedule integrated) and, GIS analysis. Monitoring was done by capturing videos of the building with a camera-equipped UAS. Still images were extracted, filtered, bundle-adjusted, and 3D as-built model was generated using open source photogrammetric software. The as-planned model was generated from digitized CAD drawings using GIS. The 3D as-built model was aligned with the 4D as-planned model of building formed from extrusion of building elements, and integration of the construction's planned schedule. The construction progress is visualized via color-coding the building elements in the 3D model. The developed methodology was conducted and applied from the data obtained from an actual construction site. Accuracy in detecting `built' or `not built' building elements ranges from 82-84 % and precision of 50-72 %. Quantified progress in terms of the number of building elements are 21.31% (November 2016), 26.84 % (January 2017) and 44.19 % (March 2017). The results can be used as an input for progress monitoring performance of construction projects and improving related decision-making process.

A globally well-posed finite element algorithm for aerodynamics applications

NASA Technical Reports Server (NTRS)

Iannelli, G. S.; Baker, A. J.

1991-01-01

A finite element CFD algorithm is developed for Euler and Navier-Stokes aerodynamic applications. For the linear basis, the resultant approximation is at least second-order-accurate in time and space for synergistic use of three procedures: (1) a Taylor weak statement, which provides for derivation of companion conservation law systems with embedded dispersion-error control mechanisms; (2) a stiffly stable second-order-accurate implicit Rosenbrock-Runge-Kutta temporal algorithm; and (3) a matrix tensor product factorization that permits efficient numerical linear algebra handling of the terminal large-matrix statement. Thorough analyses are presented regarding well-posed boundary conditions for inviscid and viscous flow specifications. Numerical solutions are generated and compared for critical evaluation of quasi-one- and two-dimensional Euler and Navier-Stokes benchmark test problems.

Postbuckling and Growth of Delaminations in Composite Plates Subjected to Axial Compression

NASA Technical Reports Server (NTRS)

Reeder, James R.; Chunchu, Prasad B.; Song, Kyongchan; Ambur, Damodar R.

2002-01-01

The postbuckling response and growth of circular delaminations in flat and curved plates are investigated as part of a study to identify the criticality of delamination locations through the laminate thickness. The experimental results from tests on delaminated plates are compared with finite element analysis results generated using shell models. The analytical prediction of delamination growth is obtained by assessing the strain energy release rate results from the finite element model and comparing them to a mixed-mode fracture toughness failure criterion. The analytical results for onset of delamination growth compare well with experimental results generated using a 3-dimensional displacement visualization system. The record of delamination progression measured in this study has resulted in a fully 3-dimensional test case with which progressive failure models can be validated.

Dismantlement of the TSF-SNAP Reactor Assembly

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

Peretz, Fred J

2009-01-01

This paper describes the dismantlement of the Tower Shielding Facility (TSF)?Systems for Nuclear Auxiliary Power (SNAP) reactor, a SNAP-10A reactor used to validate radiation source terms and shield performance models at Oak Ridge National Laboratory (ORNL) from 1967 through 1973. After shutdown, it was placed in storage at the Y-12 National Security Complex (Y-12), eventually falling under the auspices of the Highly Enriched Uranium (HEU) Disposition Program. To facilitate downblending of the HEU present in the fuel elements, the TSF-SNAP was moved to ORNL on June 24, 2006. The reactor assembly was removed from its packaging, inspected, and the sodium-potassiummore » (NaK) coolant was drained. A superheated steam process was used to chemically react the residual NaK inside the reactor assembly. The heat exchanger assembly was removed from the top of the reactor vessel, and the criticality safety sleeve was exchanged for a new safety sleeve that allowed for the removal of the vessel lid. A chain-mounted tubing cutter was used to separate the lid from the vessel, and the 36 fuel elements were removed and packaged in four U.S. Department of Transportation 2R/6M containers. The fuel elements were returned to Y-12 on July 13, 2006. The return of the fuel elements and disposal of all other reactor materials accomplished the formal objectives of the dismantlement project. In addition, a project model was established for the handling of a fully fueled liquid-metal?cooled reactor assembly. Current criticality safety codes have been benchmarked against experiments performed by Atomics International in the 1950s and 1960s. Execution of this project provides valuable experience applicable to future projects addressing space and liquid-metal-cooled reactors.« less

Structural Element Testing in Support of the Design of the NASA Composite Crew Module

NASA Technical Reports Server (NTRS)

Kellas, Sotiris; Jackson, Wade C.; Thesken, John C.; Schleicher, Eric; Wagner, Perry; Kirsch, Michael T.

2012-01-01

In January 2007, the NASA Administrator and Associate Administrator for the Exploration Systems Mission Directorate chartered the NASA Engineering and Safety Center (NESC) to design, build, and test a full-scale Composite Crew Module (CCM). For the design and manufacturing of the CCM, the team adopted the building block approach where design and manufacturing risks were mitigated through manufacturing trials and structural testing at various levels of complexity. Following NASA's Structural Design Verification Requirements, a further objective was the verification of design analysis methods and the provision of design data for critical structural features. Test articles increasing in complexity from basic material characterization coupons through structural feature elements and large structural components, to full-scale structures were evaluated. This paper discusses only four elements tests three of which include joints and one that includes a tapering honeycomb core detail. For each test series included are specimen details, instrumentation, test results, a brief analysis description, test analysis correlation and conclusions.

Neutron-Capture Elements in Very Metal-Poor Halo Stars

NASA Astrophysics Data System (ADS)

French, R. S.; Sneden, C.; Cowan, J. J.; Lawler, J. E.; Primas, F.; Beers, T. C.; Truran, J. W.

2000-05-01

Abundances of the most massive stable elements (Os -> Pb or 76 <= Z <= 82) in metal-poor stars can provide crucial information about the so-called ``third neutron-capture peak,'' and are critical to the radioactive-dating technique that uses unstable thorium and uranium as chronometers. As the relevant transitions occur in the UV and are inaccessable to ground-based telescopes, we have obtained high resolution (R ~= 30,000) UV spectra of 10 very metal-poor (--3.0 <= [Fe/H] <= --1.4) halo giants using the Space Telescope Imaging Spectrograph (STIS) aboard the Hubble Space Telescope. Using iterative spectrum synthesis techniques, we derive abundances for some of these heavy elements. We compare our abundances to those predicted for very metal-poor stars based on a scaled solar system rapid-process (production in rapid neutron-capture synthesis events, such as occurs during supernovae explosions). This research is supported by NASA STScI grant GO-08342 and NSF grants AST-9618364 to C.S. and AST-9618332 to J.J.C.

Communications between local health departments and the public during emergencies: the importance of standardized web sites.

PubMed

Fallon, L Fleming; Schmalzried, Hans D; Hasan, Nausheen

2011-01-01

Of the 2790 local health departments (LHDs) in the United States, Internet homepages were located for 1986. We reviewed each homepage to document the presence of 9 elements deemed to be critical for effective communications during emergency or disaster situations. LHD Web site homepages had a mean of 4.1 (±1.4) elements. Among the findings, this review revealed that 4 of 5 (80.5%) of the LHDs included the agency phone number, half (49.4%) provided links to emergency information, and about 1 in 5 (19.6%) listed an agency e-mail address. Fewer than 1 in 20 (4.3%) of the LHD homepages reviewed allowed visitors to sign up for automatic alerts or notifications. We suggest that these results be used as a starting point in developing a standardized template containing the 9 homepage elements. Such a template complements National Incident Management System protocols and can provide a recognizable source of consistent and reliable information for people during a public health emergency or disaster.

A Lean Six Sigma quality improvement project to increase discharge paperwork completeness for admission to a comprehensive integrated inpatient rehabilitation program.

PubMed

Neufeld, Nathan J; Hoyer, Erik H; Cabahug, Philippines; González-Fernández, Marlís; Mehta, Megha; Walker, N Colbey; Powers, Richard L; Mayer, R Samuel

2013-01-01

Lean Six Sigma (LSS) process analysis can be used to increase completeness of discharge summary reports used as a critical communication tool when a patient transitions between levels of care. The authors used the LSS methodology as an intervention to improve systems process. Over the course of the project, 8 required elements were analyzed in the discharge paperwork. The authors analyzed the discharge paperwork of patients (42 patients preintervention and 143 patients postintervention) of a comprehensive integrated inpatient rehabilitation program (CIIRP). Prior to this LSS project, 61.8% of required discharge elements were present. The intervention improved the completeness to 94.2% of the required elements. The percentage of charts that were 100% complete increased from 11.9% to 67.8%. LSS is a well-established process improvement methodology that can be used to make significant improvements in complex health care workflow issues. Specifically, the completeness of discharge documentation required for transition of care to CIIRP can be improved.

Selfish genetic elements and the gene’s-eye view of evolution

PubMed Central

2016-01-01

During the last few decades, we have seen an explosion in the influx of details about the biology of selfish genetic elements. Ever since the early days of the field, the gene’s-eye view of Richard Dawkins, George Williams, and others, has been instrumental to make sense of new empirical observations and to the generation of new hypotheses. However, the close association between selfish genetic elements and the gene’s-eye view has not been without critics and several other conceptual frameworks have been suggested. In particular, proponents of multilevel selection models have used selfish genetic elements to criticize the gene’s-eye view. In this paper, I first trace the intertwined histories of the study of selfish genetic elements and the gene’s-eye view and then discuss how their association holds up when compared with other proposed frameworks. Next, using examples from transposable elements and the major transitions, I argue that different models highlight separate aspects of the evolution of selfish genetic elements and that the productive way forward is to maintain a plurality of perspectives. Finally, I discuss how the empirical study of selfish genetic elements has implications for other conceptual issues associated with the gene’s-eye view, such as agential thinking, adaptationism, and the role of fitness maximizing models in evolution. PMID:29491953

Electronic health record systems in ophthalmology: impact on clinical documentation.

PubMed

Sanders, David S; Lattin, Daniel J; Read-Brown, Sarah; Tu, Daniel C; Wilson, David J; Hwang, Thomas S; Morrison, John C; Yackel, Thomas R; Chiang, Michael F

2013-09-01

To evaluate quantitative and qualitative differences in documentation of the ophthalmic examination between paper and electronic health record (EHR) systems. Comparative case series. One hundred fifty consecutive pairs of matched paper and EHR notes, documented by 3 attending ophthalmologist providers. An academic ophthalmology department implemented an EHR system in 2006. Database queries were performed to identify cases in which the same problems were documented by the same provider on different dates, using paper versus EHR methods. This was done for 50 consecutive pairs of examinations in 3 different diseases: age-related macular degeneration (AMD), glaucoma, and pigmented choroidal lesions (PCLs). Quantitative measures were used to compare completeness of documenting the complete ophthalmologic examination, as well as disease-specific critical findings using paper versus an EHR system. Qualitative differences in paper versus EHR documentation were illustrated by selecting representative paired examples. (1) Documentation score, defined as the number of examination elements recorded for the slit-lamp examination, fundus examination, and complete ophthalmologic examination and for critical clinical findings for each disease. (2) Paired comparison of qualitative differences in paper versus EHR documentation. For all 3 diseases (AMD, glaucoma, PCL), the number of complete examination findings recorded was significantly lower with paper than the EHR system (P ≤ 0.004). Among the 3 individual examination sections (general, slit lamp, fundus) for the 3 diseases, 5 of the 9 possible combinations had significantly lower mean documentation scores with paper than EHR notes. For 2 of the 3 diseases, the number of critical clinical findings recorded was significantly lower using paper versus EHR notes (P ≤ 0.022). All (150/150) paper notes relied on graphical representations using annotated hand-drawn sketches, whereas no (0/150) EHR notes contained drawings. Instead, the EHR systems documented clinical findings using textual descriptions and interpretations. There were quantitative and qualitative differences in the nature of paper versus EHR documentation of ophthalmic findings in this study. The EHR notes included more complete documentation of examination elements using structured textual descriptions and interpretations, whereas paper notes used graphical representations of findings. The author(s) have no proprietary or commercial interest in any materials discussed in this article. Copyright © 2013 American Academy of Ophthalmology. Published by Elsevier Inc. All rights reserved.

Zenith 1 truss transfer ceremony

NASA Technical Reports Server (NTRS)

2000-01-01

The Zenith-1 (Z-1) Truss is officially presented to NASA by The Boeing Co. on the Space Station Processing Facility floor on July 31. STS-92 Commander Col. Brian Duffy, comments on the presentation. Pictured are The Boeing Co. processing team and STS-92 astronauts. The Z-1 Truss is the cornerstone truss of the International Space Station and is scheduled to fly in Space Shuttle Discovery's payload pay on STS-92 targeted for launch Oct. 5, 2000. The Z-1 is considered a cornerstone truss because it carries critical components of the Station's attitude, communications, thermal and power control systems as well as four control moment gyros, high and low gain antenna systems, and two plasma contactor units used to disperse electrical charge build- ups. The Z-1 truss and a Pressurized Mating Adapter (PMA-3), also flying to the Station on the same mission, will be the first major U.S. elements flown to the ISS aboard the Shuttle since the launch of the Unity element in December 1998.

Zenith 1 truss transfer ceremony

NASA Technical Reports Server (NTRS)

2000-01-01

The STS-92 astronaut team study the the Zenith-1 (Z-1) Truss during the Crew Equipment Interface Test. The Z-1 Truss was officially presented to NASA by The Boeing Co. on the Space Station Processing Facility floor on July 31. The truss is the cornerstone truss of the International Space Station and is scheduled to fly in Space Shuttle Discovery's payload pay on STS- 92 targeted for launch Oct. 5, 2000. The Z-1 is considered a cornerstone truss because it carries critical components of the Station's attitude, communications, thermal and power control systems as well as four control moment gyros, high and low gain antenna systems, and two plasma contactor units used to disperse electrical charge build-ups. The Z-1 truss and a Pressurized Mating Adapter (PMA-3), also flying to the Station on the same mission, will be the first major U.S. elements flown to the ISS aboard the Shuttle since the launch of the Unity element in December 1998.

Large enhancement of superconductivity in Zr point contacts.

PubMed

Aslam, Mohammad; Singh, Chandan; Das, Shekhar; Kumar, Ritesh; Datta, Soumya; Halder, Soumyadip; Gayen, Sirshendu; Kabir, Mukul; Sheet, Goutam

2018-04-30

For certain complex superconducting systems, the superconducting properties get enhanced under mesoscopic point contacts made of elemental non-superconducting metals. However, understanding of the mechanism through which such contact induced local enhancement of superconductivity happens has been limited due to the complex nature of such compounds. In this paper we present a large enhancement of superconducting transition temperature (T_c) and superconducting energy gap (Δ) in a simple elemental superconductor Zr. While bulk Zr shows a critical temperature around 0.6K, superconductivity survives at Ag/Zr and Pt/Zr point contacts up to 3K with a corresponding five-fold enhancement of Δ. Further, the first-principles calculations on a model system provide useful insights. We show that the enhancement in superconducting properties can be attributed to a modification in the electron-phonon coupling accompanied by an enhancement of the density of states which involves the appearance of a new electron band at the Ag/Zr interfaces. © 2018 IOP Publishing Ltd.

KSC-00pp1060

NASA Image and Video Library

2000-07-31

The STS-92 astronaut team study the the Zenith-1 (Z-1) Truss during the Crew Equipment Interface Test. The Z-1 Truss was officially presented to NASA by The Boeing Co. on the Space Station Processing Facility floor on July 31. The truss is the cornerstone truss of the International Space Station and is scheduled to fly in Space Shuttle Discovery's payload pay on STS-92 targeted for launch Oct. 5, 2000. The Z-1 is considered a cornerstone truss because it carries critical components of the Station's attitude, communications, thermal and power control systems as well as four control moment gyros, high and low gain antenna systems, and two plasma contactor units used to disperse electrical charge build-ups. The Z-1 truss and a Pressurized Mating Adapter (PMA-3), also flying to the Station on the same mission, will be the first major U.S. elements flown to the ISS aboard the Shuttle since the launch of the Unity element in December 1998

KSC-00pp1059

NASA Image and Video Library

2000-07-31

The Zenith-1 (Z-1) Truss is officially presented to NASA by The Boeing Co. on the Space Station Processing Facility floor on July 31. STS-92 Commander Col. Brian Duffy discusses the significance of the Z-1 Truss during a press conference after the presentation. The Z-1 Truss is the cornerstone truss of the International Space Station and is scheduled to fly in Space Shuttle Discovery's payload pay on STS-92 targeted for launch Oct. 5, 2000. The Z-1 is considered a cornerstone truss because it carries critical components of the Station's attitude, communications, thermal and power control systems as well as four control moment gyros, high and low gain antenna systems, and two plasma contactor units used to disperse electrical charge build-ups. The Z-1 truss and a Pressurized Mating Adapter (PMA-3), also flying to the Station on the same mission, will be the first major U.S. elements flown to the ISS aboard the Shuttle since the launch of the Unity element in December 1998

KSC-00pp1058

NASA Image and Video Library

2000-07-31

The Zenith-1 (Z-1) Truss is officially presented to NASA by The Boeing Co. on the Space Station Processing Facility floor on July 31. STS-92 Commander Col. Brian Duffy, comments on the presentation. Pictured are The Boeing Co. processing team and STS-92 astronauts. The Z-1 Truss is the cornerstone truss of the International Space Station and is scheduled to fly in Space Shuttle Discovery's payload pay on STS-92 targeted for launch Oct. 5, 2000. The Z-1 is considered a cornerstone truss because it carries critical components of the Station's attitude, communications, thermal and power control systems as well as four control moment gyros, high and low gain antenna systems, and two plasma contactor units used to disperse electrical charge build-ups. The Z-1 truss and a Pressurized Mating Adapter (PMA-3), also flying to the Station on the same mission, will be the first major U.S. elements flown to the ISS aboard the Shuttle since the launch of the Unity element in December 1998

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

Nelsen, Nicholas H.; Kolb, James D.; Kulkarni, Akshay G.

Mechanical component response to shock environments must be predictable in order to ensure reliability and safety. Whether the shock input results from accidental drops during transportation to projectile impact scenarios, the system must irreversibly transition into a safe state that is incapable of triggering the component . With this critical need in mind, the 2017 Nuclear Weapons Summer Product Realization Institute (NW SPRINT) program objective sought the design of a passive shock failsafe with emphasis on additively manufactured (AM) components. Team Advanced and Exploratory (A&E) responded to the challenge by designing and delivering multiple passive shock sensing mech anisms thatmore » activate within a prescribed mechanical shock threshold. These AM failsafe designs were tuned and validated using analytical and computational techniques including the shock response spectrum (SRS) and finite element analysis (FEA). After rapid prototyping, the devices experienced physical shock tests conducted on Sandia drop tables to experimentally verify performance. Keywords: Additive manufacturing, dynamic system, failsafe, finite element analysis, mechanical shock, NW SPRINT, shock respon se spectrum« less

Flow prediction over a transport multi-element high-lift system and comparison with flight measurements

NASA Technical Reports Server (NTRS)

Vijgen, P. M. H. W.; Hardin, J. D.; Yip, L. P.

1992-01-01

Accurate prediction of surface-pressure distributions, merging boundary-layers, and separated-flow regions over multi-element high-lift airfoils is required to design advanced high-lift systems for efficient subsonic transport aircraft. The availability of detailed measurements of pressure distributions and both averaged and time-dependent boundary-layer flow parameters at flight Reynolds numbers is critical to evaluate computational methods and to model the turbulence structure for closure of the flow equations. Several detailed wind-tunnel measurements at subscale Reynolds numbers were conducted to obtain detailed flow information including the Reynolds-stress component. As part of a subsonic-transport high-lift research program, flight experiments are conducted using the NASA-Langley B737-100 research aircraft to obtain detailed flow characteristics for support of computational and wind-tunnel efforts. Planned flight measurements include pressure distributions at several spanwise locations, boundary-layer transition and separation locations, surface skin friction, as well as boundary-layer profiles and Reynolds stresses in adverse pressure-gradient flow.

Critical Elements in Fly Ash from the Combustion of Bituminous Coal in Major Polish Power Plants

NASA Astrophysics Data System (ADS)

Bielowicz, Barbara; Botor, Dariusz; Misiak, Jacek; Wagner, Marian

2018-03-01

The concentration of critical elements, including such REE as Fe, Co, W, Zn, Cr, Ni, V, Mn, Ti, Ag, Ga, Ta, Sr, Li, and Cu, in the so-called fly ash obtained from the 9 Polish power plants and 1 thermal power station has been determined. The obtained values, compared with the global average concentration in bituminous coal ash and sedimentary rocks (Clarke values), have shown that the enrichment of fly ash in the specified elements takes place in only a few bituminous coal processing sites in Poland. The enrichment factor (EF) is only slightly higher (the same order of magnitude) than the Clarke values. The enrichment factor in relation to the Clarke value in the Earth's crust reached values above 10 in all of the examined ashes for the following elements: Cr, Ni, V, W, and, in some ash samples, also Cu and Zn. The obtained values are low, only slightly higher than the global average concentrations in sedimentary rocks and bituminous coal ashes. The ferromagnetic grains (microspheres) found in bituminous coal fly ashes seem to be the most economically prospective in recovery of selected critical elements. The microanalysis has shown that iron cenospheres and plerospheres in fly ash contain, in addition to enamel and iron oxides (magnetite and hematite), iron spinels enriched in Co, Cr, Cu, Mn, Ni, W, and Zn.

Elastic Critical Axial Force for the Torsional-Flexural Buckling of Thin-Walled Metal Members: An Approximate Method

NASA Astrophysics Data System (ADS)

Kováč, Michal

2015-03-01

Thin-walled centrically compressed members with non-symmetrical or mono-symmetrical cross-sections can buckle in a torsional-flexural buckling mode. Vlasov developed a system of governing differential equations of the stability of such member cases. Solving these coupled equations in an analytic way is only possible in simple cases. Therefore, Goľdenvejzer introduced an approximate method for the solution of this system to calculate the critical axial force of torsional-flexural buckling. Moreover, this can also be used in cases of members with various boundary conditions in bending and torsion. This approximate method for the calculation of critical force has been adopted into norms. Nowadays, we can also solve governing differential equations by numerical methods, such as the finite element method (FEM). Therefore, in this paper, the results of the approximate method and the FEM were compared to each other, while considering the FEM as a reference method. This comparison shows any discrepancies of the approximate method. Attention was also paid to when and why discrepancies occur. The approximate method can be used in practice by considering some simplifications, which ensure safe results.

Compassion Satisfaction and Compassion Fatigue Among Critical Care Nurses.

PubMed

Sacco, Tara L; Ciurzynski, Susan M; Harvey, Megan Elizabeth; Ingersoll, Gail L

2015-08-01

Although critical care nurses gain satisfaction from providing compassionate care to patients and patients' families, the nurses are also at risk for fatigue. The balance between satisfaction and fatigue is considered professional quality of life. To establish the prevalence of compassion satisfaction and compassion fatigue in adult, pediatric, and neonatal critical care nurses and to describe potential contributing demographic, unit, and organizational characteristics. In a cross-sectional design, nurses were surveyed by using a demographic questionnaire and the Professional Quality of Life Scale to measure levels of compassion fatigue and compassion satisfaction. Nurses (n = 221) reported significant differences in compassion satisfaction and compassion fatigue on the basis of sex, age, educational level, unit, acuity, change in nursing management, and major systems change. Understanding the elements of professional quality of life can have a positive effect on work environment. The relationship between professional quality of life and the standards for a healthy work environment requires further investigation. Once this relationship is fully understood, interventions to improve this balance can be developed and tested. ©2015 American Association of Critical-Care Nurses.

Contact angle change during evaporation of near-critical liquids

NASA Astrophysics Data System (ADS)

Nikolayev, Vadim; Hegseth, John; Beysens, Daniel

1998-11-01

An unexpected change of the dynamic contact angle was recently observed in a near-critical liquid-gas system in a space experiment. While the near-critical liquid completely wets a solid under equilibrium conditions, the apparent contact angle changed from 0^circ to about 120^circ during evaporation. We propose an explanation for this phenomenon by taking into account vapor recoil due to evaporation (motion of the vapor from the free liquid surface). This force is normal to the vapor-liquid interface and is directed towards the liquid. It increases sharply near the triple contact line. Near the critical point, where the surface tension force is very weak, the vapor recoil force can be important enough to change the apparent contact angle. A similar effect can also explain the drying of a heater during boiling at high heat flux. The drying greatly reduces the heat transfer to the liquid causing the heater to melt. This phenomenon is called ``boiling crisis", ``burnout" or ``Departure from Nuclear Boiling". We report the preliminary results of the numerical simulation of the liquid evaporation by the Boundary Element method.

Results of adolescent health risk assesment on exposure to habitat water peroral factor in conditions of a large industrial city

NASA Astrophysics Data System (ADS)

Valeeva, E. R.; Stepanova, N. V.; Ismagilova, G. A.; Ziyatdinova, A. I.; Semanov, D. A.

2018-01-01

Results of the non-carcinogenic risk assessment on ingestion of chemical substances with drinking water showed that the risk value corresponded to the allowable level of the non-carcinogenic risk (HQ < 1) for the major part of elements in all zones. The excess of the allowable level is observed only in oil products in the 1st zone (2.05) and the 4th zone (1.04). However, the total hazard index (HI) on combined peroral ingestion of chemical compounds and elements with drinking water in selected zones of the city of Kazan implies a low risk level for adolescents living in the 1st and the 4th zones (3.7 and 3.59) correspondingly, and is dangerous for health. According to the results of analysis carried out in all zones, the following basic critical organs and systems were identified: blood, CNS, kidneys, endocrine system, cardiovascular system, skeletal system and teeth. The total hazard indices in the 1st and the 4th zones deserve particular attention. The following elements: oil products (29.7% - 54.0%), nitrates (in NO3), chloroform and fluorides make a major contribution to the value of risk. In all other zones, irrespective of the value of exposure factors, total hazard quotients indicate alarming and unacceptable risk levels at HIMe = from 4 to 8.67; and at HI 95th Perc = from 8.7 to 16.8.

HAT-P-26b: A Neptune-mass Exoplanet with Primordial Solar Heavy Element Abundance

NASA Astrophysics Data System (ADS)

Wakeford, Hannah R.; Sing, David K.; Kataria, Tiffany; Deming, Drake; Nikolov, Nikolay; Lopez, Eric; Tremblin, Pascal; Skalid Amundsen, David; Lewis, Nikole K.; Mandell, Avi; Fortney, Jonathan J.; Knutson, Heather; Benneke, Björn; Evans, Tom M.

2017-01-01

A trend in giant planet mass and atmospheric heavy elemental abundance was first noted last century from observations of planets in our own solar system. These four data points from Jupiter, Saturn, Uranus, and Neptune have served as a corner stone of planet formation theory. Here we add another point in the mass-metallicity trend from a detailed observational study of the extrasolar planet HAT-P-26b, which inhabits the critical mass regime near Neptune and Uranus. Neptune-sized worlds are among the most common planets in our galaxy and frequently exist in orbital periods very different from that of our own solar system ice giants. Atmospheric studies are the principal window into these worlds, and thereby into their formation and evolution, beyond those of our own solar system. Using the Hubble Space Telescope and Spitzer, from the optical to the infrared, we conducted a detailed atmospheric study of the Neptune-mass exoplanet HAT-P-26b over 0.5 to 4.5 μm. We detect prominent H2O absorption at 1.4 μm to 525 ppm in the atmospheric transmission spectrum. We determine that HAT-P-26b’s atmosphere is not rich in heavy elements (≈1.8×solar), which goes distinctly against the solar system mass-metallicity trend. This likely indicates that HAT-P-26b’s atmosphere is primordial and obtained its gaseous envelope late in its disk lifetime with little contamination from metal-rich planetesimals.

HAT-P-26b: A Neptune-mass Exoplanet with Primordial Solar Heavy Element Abundance

NASA Astrophysics Data System (ADS)

Wakeford, Hannah; Sing, David; Deming, Drake; Kataria, Tiffany; Lopez, Eric

2016-10-01

A trend in giant planet mass and atmospheric heavy elemental abundance was first noted last century from observations of planets in our own solar system. These four data points from Jupiter, Saturn, Uranus, and Neptune have served as a corner stone of planet formation theory. Here we add another point in the mass-metallicity trend from a detailed observational study of the extrasolar planet HAT-P-26b, which inhabits the critical mass regime near Neptune and Uranus. Neptune-sized worlds are among the most common planets in our galaxy and frequently exist in orbital periods very different from that of our own solar system ice giants. Atmospheric studies are the principal window into these worlds, and thereby into their formation and evolution, beyond those of our own solar system. Using the Hubble Space Telescope and Spitzer, from the optical to the infrared, we conducted a detailed atmospheric study of the Neptune-mass exoplanet HAT-P-26b over 0.5 to 4.5 μm. We detect prominent H2O absorption at 1.4 μm to 525 ppm in the atmospheric transmission spectrum. We determine that HAT-P-26b's atmosphere is not rich in heavy elements (≈1.8×solar), which goes distinctly against the solar system mass-metallicity trend. This likely indicates that HAT-P-26b's atmosphere is primordial and obtained its gaseous envelope late in its disk lifetime with little contamination from metal-rich planetesimals.

Episodic growth of fold-thrust belts: Insights from Finite Element Modelling

NASA Astrophysics Data System (ADS)

Yang, Xiaodong; Peel, Frank J.; Sanderson, David J.; McNeill, Lisa C.

2017-09-01

The sequential development of a fold-thrust belt was investigated using 2D Finite Element Modelling (FEM). The new model results show that a thrust system is typically composed of three distinct regions: the thrust wedge, pre-wedge, and undeformed region. The thrust wedge involves growth that repeats episodically and cyclically. A cycle of wedge building starts as frontal accretion occurs, which is accompanied by a rapid increase in wedge width reducing the taper angle below critical. In response to this, the wedge interior (tracked here by the 50 m displacement position) rapidly propagates forwards into a region of incipient folding. The taper angle progressively increases until it obtains a constant apparent critical value (∼10°). During this period, the wedge experiences significant shortening after a new thrust initiates at the failure front, leading to a decrease in wedge width. Successive widening of the wedge and subsequent shortening and thrusting maintain a reasonably constant taper angle. The fold-thrust belt evolves cyclically, through a combination of rapid advancement of the wedge and subsequent gradual, slow wedge growth. The new model results also highlights that there is clear, although minor, deformation (0-10 m horizontal displacement) in front of the thrust wedge.

A study on artificial rare earth (RE2O3) based neutron absorber.

PubMed

Kim, Kyung-O; Kyung Kim, Jong

2015-11-01

A new concept of a neutron absorption material (i.e., an artificial rare earth compound) was introduced for criticality control in a spent fuel storage system. In particular, spent nuclear fuels were considered as a potential source of rare earth elements because the nuclear fission of uranium produces a full range of nuclides. It was also found that an artificial rare earth compound (RE2O3) as a High-Level Waste (HLW) was naturally extracted from pyroprocessing technology developed for recovering uranium and transuranic elements (TRU) from spent fuels. In this study, various characteristics (e.g., activity, neutron absorption cross-section) were analyzed for validating the application possibility of this waste compound as a neutron absorption material. As a result, the artificial rare earth compound had a higher neutron absorption probability in the entire energy range, and it can be used for maintaining sub-criticality for more than 40 years on the basis of the neutron absorption capability of Boral™. Therefore, this approach is expected to vastly improve the efficiency of radioactive waste management by simultaneously keeping HLW and spent nuclear fuel in a restricted space. Copyright © 2015 Elsevier Ltd. All rights reserved.

Extraction of Molecular Features through Exome to Transcriptome Alignment

PubMed Central

Mudvari, Prakriti; Kowsari, Kamran; Cole, Charles; Mazumder, Raja; Horvath, Anelia

2014-01-01

Integrative Next Generation Sequencing (NGS) DNA and RNA analyses have very recently become feasible, and the published to date studies have discovered critical disease implicated pathways, and diagnostic and therapeutic targets. A growing number of exomes, genomes and transcriptomes from the same individual are quickly accumulating, providing unique venues for mechanistic and regulatory features analysis, and, at the same time, requiring new exploration strategies. In this study, we have integrated variation and expression information of four NGS datasets from the same individual: normal and tumor breast exomes and transcriptomes. Focusing on SNPcentered variant allelic prevalence, we illustrate analytical algorithms that can be applied to extract or validate potential regulatory elements, such as expression or growth advantage, imprinting, loss of heterozygosity (LOH), somatic changes, and RNA editing. In addition, we point to some critical elements that might bias the output and recommend alternative measures to maximize the confidence of findings. The need for such strategies is especially recognized within the growing appreciation of the concept of systems biology: integrative exploration of genome and transcriptome features reveal mechanistic and regulatory insights that reach far beyond linear addition of the individual datasets. PMID:24791251

Physiologically relevant organs on chips

PubMed Central

Yum, Kyungsuk; Hong, Soon Gweon; Lee, Luke P.

2015-01-01

Recent advances in integrating microengineering and tissue engineering have generated promising microengineered physiological models for experimental medicine and pharmaceutical research. Here we review the recent development of microengineered physiological systems, or organs on chips, that reconstitute the physiologically critical features of specific human tissues and organs and their interactions. This technology uses microengineering approaches to construct organ-specific microenvironments, reconstituting tissue structures, tissue–tissue interactions and interfaces, and dynamic mechanical and biochemical stimuli found in specific organs, to direct cells to assemble into functional tissues. We first discuss microengineering approaches to reproduce the key elements of physiologically important, dynamic mechanical microenvironments, biochemical microenvironments, and microarchitectures of specific tissues and organs in microfluidic cell culture systems. This is followed by examples of microengineered individual organ models that incorporate the key elements of physiological microenvironments into single microfluidic cell culture systems to reproduce organ-level functions. Finally, microengineered multiple organ systems that simulate multiple organ interactions to better represent human physiology, including human responses to drugs, is covered in this review. This emerging organs-on-chips technology has the potential to become an alternative to 2D and 3D cell culture and animal models for experimental medicine, human disease modeling, drug development, and toxicology. PMID:24357624

Solitonic Josephson-based meminductive systems

NASA Astrophysics Data System (ADS)

Guarcello, Claudio; Solinas, Paolo; di Ventra, Massimiliano; Giazotto, Francesco

2017-04-01

Memristors, memcapacitors, and meminductors represent an innovative generation of circuit elements whose properties depend on the state and history of the system. The hysteretic behavior of one of their constituent variables, is their distinctive fingerprint. This feature endows them with the ability to store and process information on the same physical location, a property that is expected to benefit many applications ranging from unconventional computing to adaptive electronics to robotics. Therefore, it is important to find appropriate memory elements that combine a wide range of memory states, long memory retention times, and protection against unavoidable noise. Although several physical systems belong to the general class of memelements, few of them combine these important physical features in a single component. Here, we demonstrate theoretically a superconducting memory based on solitonic long Josephson junctions. Moreover, since solitons are at the core of its operation, this system provides an intrinsic topological protection against external perturbations. We show that the Josephson critical current behaves hysteretically as an external magnetic field is properly swept. Accordingly, long Josephson junctions can be used as multi-state memories, with a controllable number of available states, and in other emerging areas such as memcomputing, i.e., computing directly in/by the memory.

Java Source Code Analysis for API Migration to Embedded Systems

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

Winter, Victor; McCoy, James A.; Guerrero, Jonathan

Embedded systems form an integral part of our technological infrastructure and oftentimes play a complex and critical role within larger systems. From the perspective of reliability, security, and safety, strong arguments can be made favoring the use of Java over C in such systems. In part, this argument is based on the assumption that suitable subsets of Java’s APIs and extension libraries are available to embedded software developers. In practice, a number of Java-based embedded processors do not support the full features of the JVM. For such processors, source code migration is a mechanism by which key abstractions offered bymore » APIs and extension libraries can made available to embedded software developers. The analysis required for Java source code-level library migration is based on the ability to correctly resolve element references to their corresponding element declarations. A key challenge in this setting is how to perform analysis for incomplete source-code bases (e.g., subsets of libraries) from which types and packages have been omitted. This article formalizes an approach that can be used to extend code bases targeted for migration in such a manner that the threats associated the analysis of incomplete code bases are eliminated.« less

Selection of rolling-element bearing steels for long-life applications

NASA Technical Reports Server (NTRS)

Zaretsky, Erwin V.

1989-01-01

Nearly four decades of research in bearing steel metallurgy and processing have resulted in improvements in bearing life by a factor of 100 over that obtained in the early 1940s. For critical applications such as aircraft, these improvements have resulted in longer lived, more reliable commercial aircraft engines. Material factors such as hardness, retained austenite, grain size and carbide size, number, and area can influence rolling-element fatigue life. Bearing steel processing such as double vacuum melting can have a greater effect on bearing life than material chemistry. The selection and specification of a bearing steel is dependent on the integration of all these considerations into the bearing design and application. The paper reviews rolling-element fatigue data and analysis which can enable the engineer or metallurgist to select a rolling-element bearing steel for critical applications where long life is required.

Selection of rolling-element bearing steels for long-life application

NASA Technical Reports Server (NTRS)

Zaretsky, E. V.

1986-01-01

Nearly four decades of research in bearing steel metallurgy and processing have resulted in improvements in bearing life by a factor of 100 over that obtained in the early 1940's. For critical applications such as aircraft, these improvements have resulted in longer lived, more reliable commercial aircraft engines. Material factors such as hardness, retained austenite, grain size and carbide size, number, and area can influence rolling-element fatigue life. Bearing steel processing such as double vacuum melting can have a greater efect on bearing life than material chemistry. The selection and specification of a bearing steel is dependent on the integration of all these considerations into the bearing design and application. The paper reviews rolling-element fatigue data and analysis which can enable the engineer or metallurgist to select a rolling-element bearing steel for critical applications where long life is required.

Cryotank Skin/Stringer Bondline Analysis

NASA Technical Reports Server (NTRS)

Nguyen, Bao

1999-01-01

The need for light weight structure for advanced launch systems have presented great challenges and led to the usage of composites materials in a variety of structural assemblies where joining of two or more components is imperative. Although joints can be mechanically bolted, adhesive bonding has always been a very desirable method for joining the composite components, particularly for the cryotank systems, to achieve maximum structural efficiency. This paper presents the analytical approach resulted from the conceptual development of the DC-Y composite cryotank, conducted under the NASA/Boeing NRA 8-12 Partnership, to support the continued progress of SSTO (Single-Stage-To-Orbit) concepts. One of the critical areas of design was identified as the bonded interface between the skin (tank wall) and stringer. The approach to analyze this critical area will be illustrated through the steps which were used to evaluate the structural integrity of the bondline. Detailed finite element models were developed and numerous coupon test data were also gathered as part of the approach. Future plan is to incorporate this approach as a building block in analyzing bondline for the cryotank systems of RLVs (Reusable Launch Vehicles).

Critical infrastructure protection: why physicians, nurses, and other healthcare professionals need to be involved.

PubMed

Lavin, Roberta; Harrington, Michael B; Agbor-tabi, Elisabeth; Erger, Nurit

2006-01-01

What is present in nearly every U.S. community, performs myriad services from the routine to the life saving on a daily basis, responds to every disaster, and functions 24 hours a day every day of the year? The answer, of course, is the nation's $1.8 trillion public health and healthcare system. Protection of this system's vast infrastructure has assumed increasing urgency since September 11, and there are at least two reasons for this. The first is that this sector must respond to every conceivable event involving risks to human life, including those traditionally within the purview of public health, so its ability to respond to these events must be preserved. The second is that elements of the sector itself face increasing threats to facilities, information systems, and workforces. These reasons alone warrant greater emphasis on protective programs than may have seemed necessary in the past, and the public health and healthcare sector should recognize that it must now understand critical infrastructure protection as well as it does healthcare management.

Helping Students to Recognize and Evaluate an Assumption in Quantitative Reasoning: A Basic Critical-Thinking Activity with Marbles and Electronic Balance

ERIC Educational Resources Information Center

Slisko, Josip; Cruz, Adrian Corona

2013-01-01

There is a general agreement that critical thinking is an important element of 21st century skills. Although critical thinking is a very complex and controversial conception, many would accept that recognition and evaluation of assumptions is a basic critical-thinking process. When students use simple mathematical model to reason quantitatively…

Lee as Critical Thinker: The Example of the Gettysburg Campaign

DTIC Science & Technology

2012-05-04

well as what should have been done if the critical thinking process had been conducted appropriately. Conclusion: Several human and military...of reasoning that make up the cognitive decision making process .6 The critical thinking elements of the model (Clarify Concern, Point of View...Finally, there are three remaining biases, traps, and errors that can negatively affect the critical thinking process . A confirmation trap describes

An enhanced MMW and SMMW/THz imaging system performance prediction and analysis tool for concealed weapon detection and pilotage obstacle avoidance

NASA Astrophysics Data System (ADS)

Murrill, Steven R.; Jacobs, Eddie L.; Franck, Charmaine C.; Petkie, Douglas T.; De Lucia, Frank C.

2015-10-01

The U.S. Army Research Laboratory (ARL) has continued to develop and enhance a millimeter-wave (MMW) and submillimeter- wave (SMMW)/terahertz (THz)-band imaging system performance prediction and analysis tool for both the detection and identification of concealed weaponry, and for pilotage obstacle avoidance. The details of the MATLAB-based model which accounts for the effects of all critical sensor and display components, for the effects of atmospheric attenuation, concealment material attenuation, and active illumination, were reported on at the 2005 SPIE Europe Security and Defence Symposium (Brugge). An advanced version of the base model that accounts for both the dramatic impact that target and background orientation can have on target observability as related to specular and Lambertian reflections captured by an active-illumination-based imaging system, and for the impact of target and background thermal emission, was reported on at the 2007 SPIE Defense and Security Symposium (Orlando). Further development of this tool that includes a MODTRAN-based atmospheric attenuation calculator and advanced system architecture configuration inputs that allow for straightforward performance analysis of active or passive systems based on scanning (single- or line-array detector element(s)) or staring (focal-plane-array detector elements) imaging architectures was reported on at the 2011 SPIE Europe Security and Defence Symposium (Prague). This paper provides a comprehensive review of a newly enhanced MMW and SMMW/THz imaging system analysis and design tool that now includes an improved noise sub-model for more accurate and reliable performance predictions, the capability to account for postcapture image contrast enhancement, and the capability to account for concealment material backscatter with active-illumination- based systems. Present plans for additional expansion of the model's predictive capabilities are also outlined.

Current Practices in Runway Configuration Management (RCM) and Arrival/Departure Runway Balancing (ADRB)

NASA Technical Reports Server (NTRS)

Lohr, Gary W.; Williams, Daniel M.

2008-01-01

Significant air traffic increases are anticipated for the future of the National Airspace System (NAS). To cope with future traffic increases, fundamental changes are required in many aspects of the air traffic management process including the planning and use of NAS resources. Two critical elements of this process are the selection of airport runway configurations, and the effective management of active runways. Two specific research areas in NASA's Airspace Systems Program (ASP) have been identified to address efficient runway management: Runway Configuration Management (RCM) and Arrival/Departure Runway Balancing (ADRB). This report documents efforts in assessing past as well as current work in these two areas.

Arctic melt ponds and energy balance in the climate system

NASA Astrophysics Data System (ADS)

Sudakov, Ivan

2017-02-01

Elements of Earth's cryosphere, such as the summer Arctic sea ice pack, are melting at precipitous rates that have far outpaced the projections of large scale climate models. Understanding key processes, such as the evolution of melt ponds that form atop Arctic sea ice and control its optical properties, is crucial to improving climate projections. These types of critical phenomena in the cryosphere are of increasing interest as the climate system warms, and are crucial for predicting its stability. In this paper, we consider how geometrical properties of melt ponds can influence ice-albedo feedback and how it can influence the equilibria in the energy balance of the planet.

Nature of non-nuclear (3, -3) π-attractor and π-bonding: Theoretical analysis on π-electron density

NASA Astrophysics Data System (ADS)

Lv, Jiao; Yang, Lihua; Sun, Zheng; Meng, Lingpeng; Li, Xiaoyan

2018-01-01

Understanding the nature of π-electron density is important to characterize the conjugate π molecular systems. In this work, the π-electron densities of some typical conjugated π molecular systems were separated from their total electron densities; the positions and natures of non-nuclear (3, -3) π-attractors and the π-bond critical points (π-BCPs) are investigated. The calculated results show that for the same element, the position of the π-attractor is constant, regardless of the chemical surroundings. The position of the π-BCP is closer to the atom with the larger electronegativity.

Design and operations technologies - Integrating the pieces. [for future space systems design

NASA Technical Reports Server (NTRS)

Eldred, C. H.

1979-01-01

As major elements of life-cycle costs (LCC) having critical impacts on the initiation and utilization of future space programs, the areas of vehicle design and operations are reviewed in order to identify technology requirements. Common to both areas is the requirement for efficient integration of broad, complex systems. Operations technologies focus on the extension of space-based capabilities and cost reduction through the combination of innovative design, low-maintenance hardware, and increased manpower productivity. Design technologies focus on computer-aided techniques which increase productivity while maintaining a high degree of flexibility which enhances creativity and permits graceful design changes.

Design and manufacturing methods for the integral field unit of the nirspec instrument on JWST

NASA Astrophysics Data System (ADS)

Lobb, Dan; Robertson, David

2017-11-01

An integral field unit, to be used with the near-IR spectrometer instrument of the James Webb Space Telescope (JWST), is currently under development by SSTL and CfAI. Special problems in design and manufacture of the optical system are outlined, and manufacturing methods for critical optical elements are discussed. The optical system is complex, requiring a total of 95 mirrors to produce 30 output channels. Emphasis is placed on the advantages of free-form machining in aluminium. These include: resistance to launch stress, insensitivity to temperature variations from ambient to cryogenic, and the possibility of relatively complex mirror surface shapes.

RF Frequency Oscillations in the Early Stages of Vacuum Arc Collapse

NASA Technical Reports Server (NTRS)

Griffin, Steven T.; Thio, Y. C. Francis

2003-01-01

RF frequency oscillations may be produced in a typical capacitive charging / discharging pulsed power system. These oscillations may be benign, parasitic, destructive or crucial to energy deposition. In some applications, proper damping of oscillations may be critical to proper plasma formation. Because the energy deposited into the plasma is a function of plasma and circuit conditions, the entire plasma / circuit system needs to be considered as a unit To accomplish this, the initiation of plasma is modeled as a time-varying, non-linear element in a circuit analysis model. The predicted spectra are compared to empirical power density spectra including those obtained from vacuum arcs.

Opportunities for Fundamental University-Based Research in Energy and Resource Recovery

NASA Astrophysics Data System (ADS)

Zoback, M. D.; Hitzman, M.; Tester, J. W.

2012-12-01

In this talk we present, from a university perspective, a few examples of fundamental research needs related to improved energy and resource recovery. One example of such a research need is related to the fact that it is not widely recognized that meeting domestic and worldwide energy needs with renewables such as wind and solar will be materials intensive. If widely deployed, the elements required by renewable technologies will be needed in significant quantities and shortage of these "energy critical elements" could significantly inhibit the adoption of otherwise game changing energy technologies. It is imperative to better understand the geology, metallurgy, and mining engineering of critical mineral deposits if we are to sustainably develop these new technologies. Unfortunately, there is currently no consensus among federal and state agencies, the national and international mining industry, the public, and the U.S. academic community regarding the importance of economic geology in the context of securing sufficient energy critical elements to undertake large-scale renewable energy development. Another option for transitioning away from our current hydrocarbon-based energy system to non-carbon based sources, is geothermal energy - from both conventional hydrothermal resources and enhanced or engineered geothermal systems (EGS). Although geothermal energy is currently used for both electric and non-electric applications worldwide from conventional hydrothermal resources and in ground source heat pumps, most of the emphasis in the US has been generating electricity. To this end, there is a need for research, development and demonstration in five important areas - estimating the magnitude and distribution of recoverable geothermal resources, establishing requirements for extracting and utilizing energy from EGS reservoirs the including drilling, reservoir design and stimulation, exploring end use options for district heating, electricity generation and co-generation, evaluating environmental impacts and tradeoffs (from dealing with water and land use to seismic risk) and projecting costs for EGS supplied electricity as a function of invested funds in research and development and deployment in evolving energy markets Finally, the shale gas revolution that has been underway in North America for the past few years has been of unprecedented scale and importance. As such resources are beginning to be developed globally, there is a critical need for fundamental research on such questions as how shale properties affect the success of stimulation, the importance of seismic and aseismic deformation mechanisms during reservoir stimulation, the factors that affect ultimate recovery and the development of methodologies that minimize the environmental impact of shale gas development.

Empirical Critical Loads of Atmospheric Nitrogen Deposition for Nutrient Enrichment and Acidification of Sensitive US Lakes

EPA Science Inventory

A critical load is a “quantitative estimate of the exposure to one or more pollutants below which significant harmful effects on specified sensitive elements of the environment do not occur according to present knowledge”. Critical loads can be either modeled, or calculated empi...

The Three-Part Harmony of Adult Learning, Critical Thinking, and Decision-Making

ERIC Educational Resources Information Center

Moore, Kyle

2010-01-01

Adult learning, critical thinking, and decision-making are fields that receive attention individually, although they are interspersed with elements of each other's theories and philosophies. In addressing adult learning precepts, it is essential to include critical thinking and decision-making. One without the other creates weakness; all must be…

A Critical Theory of Adult and Community Education

ERIC Educational Resources Information Center

Brookfield, Stephen

2012-01-01

Critical theory is one of the most influential theoretical frameworks influencing scholarship within the field of adult and community education. This chapter outlines what constitute the chief elements of critical theory using Horkheimer's (1937/1995) classic essay as a touchstone for this analysis. It argues for a set of adult learning tasks that…

Reinventing Critical Pedagogy: Widening the Circle of Anti-Oppression Education

ERIC Educational Resources Information Center

Rossatto, Cesar Augusto; Allen, Ricky Lee; Pruyn, Marc

2006-01-01

This book offers a fresh perspective from which to read, discuss, and debate recent critical interpretations of schooling and our world at present. The authors build upon past accomplishments of critical pedagogy and critique those elements that contradict the radically democratic orientation of the field. Ultimately, they argue that critical…

SKYWARD: the next generation airborne infrared search and track

NASA Astrophysics Data System (ADS)

Fortunato, L.; Colombi, G.; Ondini, A.; Quaranta, C.; Giunti, C.; Sozzi, B.; Balzarotti, G.

2016-05-01

Infrared Search and Track systems are an essential element of the modern and future combat aircrafts. Passive automatic search, detection and tracking functions, are key points for silent operations or jammed tactical scenarios. SKYWARD represents the latest evolution of IRST technology in which high quality electro-optical components, advanced algorithms, efficient hardware and software solutions are harmonically integrated to provide high-end affordable performances. Additionally, the reduction of critical opto-mechanical elements optimises weight and volume and increases the overall reliability. Multiple operative modes dedicated to different situations are available; many options can be selected among multiple or single target tracking, for surveillance or engagement, and imaging, for landing or navigation aid, assuring the maximum system flexibility. The high quality 2D-IR sensor is exploited by multiple parallel processing chains, based on linear and non-linear techniques, to extract the possible targets from background, in different conditions, with false alarm rate control. A widely tested track processor manages a large amount of candidate targets simultaneously and allows discriminating real targets from noise whilst operating with low target to background contrasts. The capability of providing reliable passive range estimation is an additional qualifying element of the system. Particular care has been dedicated to the detector non-uniformities, a possible limiting factor for distant targets detection, as well as to the design of the electro-optics for a harsh airborne environment. The system can be configured for LWIR or MWIR waveband according to the customer operational requirements. An embedded data recorder saves all the necessary images and data for mission debriefing, particularly useful during inflight system integration and tuning.

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

NASA Astrophysics Data System (ADS)

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

2017-08-01

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

Damage Characterization Using the Extended Finite Element Method for Structural Health Management

NASA Technical Reports Server (NTRS)

Krishnamurthy, Thiagarajan; Gallegos, Adam M.

2011-01-01

The development of validated multidisciplinary Integrated Vehicle Health Management (IVHM) tools, technologies, and techniques to enable detection, diagnosis, prognosis, and mitigation in the presence of adverse conditions during flight will provide effective solutions to deal with safety related challenges facing next generation aircraft. The adverse conditions include loss of control caused by environmental factors, actuator and sensor faults or failures, and damage conditions. A major concern in these structures is the growth of undetected damage/cracks due to fatigue and low velocity foreign impact that can reach a critical size during flight, resulting in loss of control of the aircraft. Hence, development of efficient methodologies to determine the presence, location, and severity of damage/cracks in critical structural components is highly important in developing efficient structural health management systems.

Physical approach to complex systems

NASA Astrophysics Data System (ADS)

Kwapień, Jarosław; Drożdż, Stanisław

2012-06-01

Typically, complex systems are natural or social systems which consist of a large number of nonlinearly interacting elements. These systems are open, they interchange information or mass with environment and constantly modify their internal structure and patterns of activity in the process of self-organization. As a result, they are flexible and easily adapt to variable external conditions. However, the most striking property of such systems is the existence of emergent phenomena which cannot be simply derived or predicted solely from the knowledge of the systems’ structure and the interactions among their individual elements. This property points to the holistic approaches which require giving parallel descriptions of the same system on different levels of its organization. There is strong evidence-consolidated also in the present review-that different, even apparently disparate complex systems can have astonishingly similar characteristics both in their structure and in their behaviour. One can thus expect the existence of some common, universal laws that govern their properties. Physics methodology proves helpful in addressing many of the related issues. In this review, we advocate some of the computational methods which in our opinion are especially fruitful in extracting information on selected-but at the same time most representative-complex systems like human brain, financial markets and natural language, from the time series representing the observables associated with these systems. The properties we focus on comprise the collective effects and their coexistence with noise, long-range interactions, the interplay between determinism and flexibility in evolution, scale invariance, criticality, multifractality and hierarchical structure. The methods described either originate from “hard” physics-like the random matrix theory-and then were transmitted to other fields of science via the field of complex systems research, or they originated elsewhere but turned out to be very useful also in physics - like, for example, fractal geometry. Further methods discussed borrow from the formalism of complex networks, from the theory of critical phenomena and from nonextensive statistical mechanics. Each of these methods is helpful in analyses of specific aspects of complexity and all of them are mutually complementary.

Cockpit emergency safety system

NASA Astrophysics Data System (ADS)

Keller, Leo

2000-06-01

A comprehensive safety concept is proposed for aircraft's experiencing an incident to the development of fire and smoke in the cockpit. Fire or excessive heat development caused by malfunctioning electrical appliance may produce toxic smoke, may reduce the clear vision to the instrument panel and may cause health-critical respiration conditions. Immediate reaction of the crew, safe respiration conditions and a clear undisturbed view to critical flight information data can be assumed to be the prerequisites for a safe emergency landing. The personal safety equipment of the aircraft has to be effective in supporting the crew to divert the aircraft to an alternate airport in the shortest possible amount of time. Many other elements in the cause-and-effect context of the emergence of fire, such as fire prevention, fire detection, the fire extinguishing concept, systematic redundancy, the wiring concept, the design of the power supplying system and concise emergency checklist procedures are briefly reviewed, because only a comprehensive and complete approach will avoid fatal accidents of complex aircraft in the future.

Structuring payment to medical homes after the affordable care act.

PubMed

Edwards, Samuel T; Abrams, Melinda K; Baron, Richard J; Berenson, Robert A; Rich, Eugene C; Rosenthal, Gary E; Rosenthal, Meredith B; Landon, Bruce E

2014-10-01

The Patient-Centered Medical Home (PCMH) is a leading model of primary care reform, a critical element of which is payment reform for primary care services. With the passage of the Affordable Care Act, the Accountable Care Organization (ACO) has emerged as a model of delivery system reform, and while there is theoretical alignment between the PCMH and ACOs, the discussion of physician payment within each model has remained distinct. Here we compare payment for medical homes with that for accountable care organizations, consider opportunities for integration, and discuss implications for policy makers and payers considering ACO models. The PCMH and ACO are complementary approaches to reformed care delivery: the PCMH ultimately requires strong integration with specialists and hospitals as seen under ACOs, and ACOs likely will require a high functioning primary care system as embodied by the PCMH. Aligning payment incentives within the ACO will be critical to achieving this integration and enhancing the care coordination role of primary care in these settings.

Experience with soluble neutron poisons for criticality control at ICPP

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

Wilson, R.E.; Mortimer, S.R.

1978-01-01

Soluble neutron poisons assure criticality control in two of the headend fuel reprocessing systems at the Idaho Chemical Processing Plant. Soluble poisons have been used successfully since 1964 and will be employed in the projected new headend processes. The use of soluble poisons (1) greatly increases the process output (2) allows versatility in the size of fuel assemblies processed and (3) allows the practical reprocessing of some fuels. The safety limit for all fluids entering the U-Zr alloy dissolver is 3.6 g/liter boron. To allow for possible deviations in the measurement systems and drift between analytical sampling periods, the standardmore » practice is to use 3.85 g/liter boron as the lower limit. This dissolver has had 4000 successful hours of operation using soluble poisons. The electrolytic dissolution process depends on soluble gadolinium for criticality safety. This system is used to process high enriched uranium clad in stainless steel. Electrolytic dissolution takes advantage of the anodic corrosion that occurs when a large electrical current is passed through the fuel elements in a corrosive environment. Three control methods are used on each headend system. First, the poison is mixed according to standard operating procedures and the measurements are affirmed by the operator's supervisor. Second, the poisoned solution is stirred, sampled, analyzed, and the analysis reported while still in the mix tank. Finally, a Nuclear Poison Detection System (NPDS) must show an acceptable poison concentration before the solution can be transferred. The major disadvantage of using soluble poisons is the need for very sophisticated control systems and procedures, which require extensive checkout. The need for a poisoned primary heating and cooling system means a secondary system is needed as well. Experience has shown, however, that production enhancement more than makes up for the problems.« less

The Role of Transition Metal Transporters for Iron, Zinc, Manganese, and Copper in the Pathogenesis of Yersinia pestis

PubMed Central

Perry, Robert D.; Bobrov, Alexander G.; Fetherston, Jacqueline D.

2015-01-01

Yersinia pestis, the causative agent of bubonic, septicemic and pneumonic plague, encodes a multitude of Fe transport systems. Some of these are defective due to frameshift or IS element insertions, while others are functional in vitro but have no established role in causing infections. Indeed only 3 Fe transporters (Ybt, Yfe and Feo) have been shown to be important in at least one form of plague. The yersiniabactin (Ybt) system is essential in the early dermal/lymphatic stages of bubonic plague, irrelevant in the septicemic stage, and critical in pneumonic plague. Two Mn transporters have been characterized (Yfe and MntH). These two systems play a role in bubonic plague but the double yfe mntH mutant is fully virulent in a mouse model of pneumonic plague. The same in vivo phenotype occurs with a mutant lacking two (Yfe and Feo) of four ferrous transporters. A role for the Ybt siderophore in Zn acquisition has been revealed. Ybt-dependent Zn acquisition uses a transport system completely independent of the Fe-Ybt uptake system. Together Ybt components and ZnuABC play a critical role in Zn acquisition in vivo. Single mutants in either system retain high virulence in a mouse model of septicemic plague while the double mutant is completely avirulent. PMID:25891079

The role of transition metal transporters for iron, zinc, manganese, and copper in the pathogenesis of Yersinia pestis.

PubMed

Perry, Robert D; Bobrov, Alexander G; Fetherston, Jacqueline D

2015-06-01

Yersinia pestis, the causative agent of bubonic, septicemic and pneumonic plague, encodes a multitude of Fe transport systems. Some of these are defective due to frameshift or IS element insertions, while others are functional in vitro but have no established role in causing infections. Indeed only 3 Fe transporters (Ybt, Yfe and Feo) have been shown to be important in at least one form of plague. The yersiniabactin (Ybt) system is essential in the early dermal/lymphatic stages of bubonic plague, irrelevant in the septicemic stage, and critical in pneumonic plague. Two Mn transporters have been characterized (Yfe and MntH). These two systems play a role in bubonic plague but the double yfe mntH mutant is fully virulent in a mouse model of pneumonic plague. The same in vivo phenotype occurs with a mutant lacking two (Yfe and Feo) of four ferrous transporters. A role for the Ybt siderophore in Zn acquisition has been revealed. Ybt-dependent Zn acquisition uses a transport system completely independent of the Fe-Ybt uptake system. Together Ybt components and ZnuABC play a critical role in Zn acquisition in vivo. Single mutants in either system retain high virulence in a mouse model of septicemic plague while the double mutant is completely avirulent.

Outsourcing critical financial system operations.

PubMed

Cox, Nora; Pilbauer, Jan

2018-01-01

Payments Canada provides Canada's national payments systems and is responsible for the clearing and settlement infrastructure, processes and rules that underpin the exchange of billions of dollars each day through the Canadian economy. Strategic sourcing is a reality for this small organisation with a broad scope of national regulations and global standards to comply with. This paper outlines Payments Canada's approach to outsourcing its critical financial system operations, which centres on four key principles: strong relationship management; continuous learning, recording and reporting; evaluating the business landscape; and a commitment to evolving the organisation to greater resilience. This last point is covered in detail with an exploration of the organisation's resilience and security strategy as well as its risk appetite. As Payments Canada progresses to its future state, which includes modernising its core payment systems, underlying rules and standards, risk management for the industry as a whole will remain at the forefront of its collective mind. The expectation is that outsourcing will remain a fundamental element of its operating model in future, a strategy that will ensure the organisation can focus on its core business competencies and eliminate the need to develop and support in-house expertise in commodity areas.

Topographic measurement of buried thin-film interfaces using a grazing resonant soft x-ray scattering technique

NASA Astrophysics Data System (ADS)

Gann, Eliot; Watson, Anne; Tumbleston, John R.; Cochran, Justin; Yan, Hongping; Wang, Cheng; Seok, Jaewook; Chabinyc, Michael; Ade, Harald

2014-12-01

The internal structures of thin films, particularly interfaces between different materials, are critical to system properties and performance across many disciplines, but characterization of buried interface topography is often unfeasible. In this work, we demonstrate that grazing resonant soft x-ray scattering (GRSoXS), a technique measuring diffusely scattered soft x rays from grazing incidence, can reveal the statistical topography of buried thin-film interfaces. By controlling and predicting the x-ray electric field intensity throughout the depth of the film and simultaneously the scattering contrast between materials, we are able to unambiguously identify the microstructure at different interfaces of a model polymer bilayer system. We additionally demonstrate the use of GRSoXS to selectively measure the topography of the surface and buried polymer-polymer interface in an organic thin-film transistor, revealing different microstructure and markedly differing evolution upon annealing. In such systems, where only indirect control of interface topography is possible, accurate measurement of the structure of interfaces for feedback is critically important. While we demonstrate the method here using organic materials, we also show that the technique is readily extendable to any thin-film system with elemental or chemical contrasts exploitable at absorption edges.

The relationship between students critical thinking measured by science virtual test and students logical thinking on eighth grade secondary school

NASA Astrophysics Data System (ADS)

Nurismawati, R.; Sanjaya, Y.; Rusyati, L.

2018-05-01

The aim of this study is to examine the relationship between students’ critical thinking skill and students’ logical thinking skill of Junior High School students in Tasikmalaya city. The respondent consists of 168 students from eighth grade at three public schools in Tasikmalaya City. Science Virtual Test and Test of Logical Thinking were used in this research study. Science virtual test instrument consist of 26 questions with 5 different topics. IBM SPSS 23.00 program was used for analysis of the data. By the findings; students’ critical thinking skill has significant differences in elements of generating purpose, embodying point of view, utilizing concept and making implication and consequence. By Post Hoc LSD Test, from those four elements, there are significant differences between concrete - transitional groups and transitional – concrete groups. There is positive and weak correlation between students’ critical thinking and students’ logical thinking attainment.

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

Van Der Marck, S. C.

Three nuclear data libraries have been tested extensively using criticality safety benchmark calculations. The three libraries are the new release of the US library ENDF/B-VII.1 (2011), the new release of the Japanese library JENDL-4.0 (2011), and the OECD/NEA library JEFF-3.1 (2006). All calculations were performed with the continuous-energy Monte Carlo code MCNP (version 4C3, as well as version 6-beta1). Around 2000 benchmark cases from the International Handbook of Criticality Safety Benchmark Experiments (ICSBEP) were used. The results were analyzed per ICSBEP category, and per element. Overall, the three libraries show similar performance on most criticality safety benchmarks. The largest differencesmore » are probably caused by elements such as Be, C, Fe, Zr, W. (authors)« less

Dynamic modelling and response characteristics of a magnetic bearing rotor system with auxiliary bearings

NASA Technical Reports Server (NTRS)

Free, April M.; Flowers, George T.; Trent, Victor S.

1995-01-01

Auxiliary bearings are a critical feature of any magnetic bearing system. They protect the soft iron core of the magnetic bearing during an overload or failure. An auxiliary bearing typically consists of a rolling element bearing or bushing with a clearance gap between the rotor and the inner race of the support. The dynamics of such systems can be quite complex. It is desired to develop a rotordynamic model which describes the dynamic behavior of a flexible rotor system with magnetic bearings including auxiliary bearings. The model is based upon an experimental test facility. Some simulation studies are presented to illustrate the behavior of the model. In particular, the effects of introducing sideloading from the magnetic bearing when one coil fails is studied.