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Sample records for achieve reliable operation

  1. Understanding the Elements of Operational Reliability: A Key for Achieving High Reliability

    NASA Technical Reports Server (NTRS)

    Safie, Fayssal M.

    2010-01-01

    This viewgraph presentation reviews operational reliability and its role in achieving high reliability through design and process reliability. The topics include: 1) Reliability Engineering Major Areas and interfaces; 2) Design Reliability; 3) Process Reliability; and 4) Reliability Applications.

  2. Achieving High Reliability Operations Through Multi-Program Integration

    SciTech Connect

    Holly M. Ashley; Ronald K. Farris; Robert E. Richards

    2009-04-01

    Over the last 20 years the Idaho National Laboratory (INL) has adopted a number of operations and safety-related programs which has each periodically taken its turn in the limelight. As new programs have come along there has been natural competition for resources, focus and commitment. In the last few years, the INL has made real progress in integrating all these programs and are starting to realize important synergies. Contributing to this integration are both collaborative individuals and an emerging shared vision and goal of the INL fully maturing in its high reliability operations. This goal is so powerful because the concept of high reliability operations (and the resulting organizations) is a masterful amalgam and orchestrator of the best of all the participating programs (i.e. conduct of operations, behavior based safety, human performance, voluntary protection, quality assurance, and integrated safety management). This paper is a brief recounting of the lessons learned, thus far, at the INL in bringing previously competing programs into harmony under the goal (umbrella) of seeking to perform regularly as a high reliability organization. In addition to a brief diagram-illustrated historical review, the authors will share the INL’s primary successes (things already effectively stopped or started) and the gaps yet to be bridged.

  3. Achieving Reliable Communication in Dynamic Emergency Responses

    PubMed Central

    Chipara, Octav; Plymoth, Anders N.; Liu, Fang; Huang, Ricky; Evans, Brian; Johansson, Per; Rao, Ramesh; Griswold, William G.

    2011-01-01

    Emergency responses require the coordination of first responders to assess the condition of victims, stabilize their condition, and transport them to hospitals based on the severity of their injuries. WIISARD is a system designed to facilitate the collection of medical information and its reliable dissemination during emergency responses. A key challenge in WIISARD is to deliver data with high reliability as first responders move and operate in a dynamic radio environment fraught with frequent network disconnections. The initial WIISARD system employed a client-server architecture and an ad-hoc routing protocol was used to exchange data. The system had low reliability when deployed during emergency drills. In this paper, we identify the underlying causes of unreliability and propose a novel peer-to-peer architecture that in combination with a gossip-based communication protocol achieves high reliability. Empirical studies show that compared to the initial WIISARD system, the redesigned system improves reliability by as much as 37% while reducing the number of transmitted packets by 23%. PMID:22195075

  4. Reliability achievement in high technology space systems

    NASA Technical Reports Server (NTRS)

    Lindstrom, D. L.

    1981-01-01

    The production of failure-free hardware is discussed. The elements required to achieve such hardware are: technical expertise to design, analyze, and fully understand the design; use of high reliability parts and materials control in the manufacturing process; and testing to understand the system and weed out defects. The durability of the Hughes family of satellites is highlighted.

  5. Achieving TASAR Operational Readiness

    NASA Technical Reports Server (NTRS)

    Wing, David J.

    2015-01-01

    NASA has been developing and testing the Traffic Aware Strategic Aircrew Requests (TASAR) concept for aircraft operations featuring a NASA-developed cockpit automation tool, the Traffic Aware Planner (TAP), which computes traffic/hazard-compatible route changes to improve flight efficiency. The TAP technology is anticipated to save fuel and flight time and thereby provide immediate and pervasive benefits to the aircraft operator, as well as improving flight schedule compliance, passenger comfort, and pilot and controller workload. Previous work has indicated the potential for significant benefits for TASAR-equipped aircraft, and a flight trial of the TAP software application in the National Airspace System has demonstrated its technical viability. This paper reviews previous and ongoing activities to prepare TASAR for operational use.

  6. Reliability Considerations for the Operation of Large Accelerator User Facilities

    SciTech Connect

    Willeke, F. J.

    2016-01-29

    The lecture provides an overview of considerations relevant for achieving highly reliable operation of accelerator based user facilities. The article starts with an overview of statistical reliability formalism which is followed by high reliability design considerations with examples. Finally, the article closes with operational aspects of high reliability such as preventive maintenance and spares inventory.

  7. Reliability measurement for operational avionics software

    NASA Technical Reports Server (NTRS)

    Thacker, J.; Ovadia, F.

    1979-01-01

    Quantitative measures of reliability for operational software in embedded avionics computer systems are presented. Analysis is carried out on data collected during flight testing and from both static and dynamic simulation testing. Failure rate is found to be a useful statistic for estimating software quality and recognizing reliability trends during the operational phase of software development.

  8. Methods and Costs to Achieve Ultra Reliable Life Support

    NASA Technical Reports Server (NTRS)

    Jones, Harry W.

    2012-01-01

    A published Mars mission is used to explore the methods and costs to achieve ultra reliable life support. The Mars mission and its recycling life support design are described. The life support systems were made triply redundant, implying that each individual system will have fairly good reliability. Ultra reliable life support is needed for Mars and other long, distant missions. Current systems apparently have insufficient reliability. The life cycle cost of the Mars life support system is estimated. Reliability can be increased by improving the intrinsic system reliability, adding spare parts, or by providing technically diverse redundant systems. The costs of these approaches are estimated. Adding spares is least costly but may be defeated by common cause failures. Using two technically diverse systems is effective but doubles the life cycle cost. Achieving ultra reliability is worth its high cost because the penalty for failure is very high.

  9. Operational reliability of standby safety systems

    SciTech Connect

    Grant, G.M.; Atwood, C.L.; Gentillon, C.D.

    1995-04-01

    The Idaho National Engineering Laboratory (INEL) is evaluating the operational reliability of several risk-significant standby safety systems based on the operating experience at US commercial nuclear power plants from 1987 through 1993. The reliability assessed is the probability that the system will perform its Probabilistic Risk Assessment (PRA) defined safety function. The quantitative estimates of system reliability are expected to be useful in risk-based regulation. This paper is an overview of the analysis methods and the results of the high pressure coolant injection (HPCI) system reliability study. Key characteristics include (1) descriptions of the data collection and analysis methods, (2) the statistical methods employed to estimate operational unreliability, (3) a description of how the operational unreliability estimates were compared with typical PRA results, both overall and for each dominant failure mode, and (4) a summary of results of the study.

  10. Reliable multicast protocol specifications protocol operations

    NASA Technical Reports Server (NTRS)

    Callahan, John R.; Montgomery, Todd; Whetten, Brian

    1995-01-01

    This appendix contains the complete state tables for Reliable Multicast Protocol (RMP) Normal Operation, Multi-RPC Extensions, Membership Change Extensions, and Reformation Extensions. First the event types are presented. Afterwards, each RMP operation state, normal and extended, is presented individually and its events shown. Events in the RMP specification are one of several things: (1) arriving packets, (2) expired alarms, (3) user events, (4) exceptional conditions.

  11. Reliability Technology to Achieve Insertion of Advanced Packaging (RELTECH) program

    NASA Technical Reports Server (NTRS)

    Fayette, Daniel F.; Speicher, Patricia; Stoklosa, Mark J.; Evans, Jillian V.; Evans, John W.; Gentile, Mike; Pagel, Chuck A.; Hakim, Edward

    1993-01-01

    A joint military-commercial effort to evaluate multichip module (MCM) structures is discussed. The program, Reliability Technology to Achieve Insertion of Advanced Packaging (RELTECH), has been designed to identify the failure mechanisms that are possible in MCM structures. The RELTECH test vehicles, technical assessment task, product evaluation plan, reliability modeling task, accelerated and environmental testing, and post-test physical analysis and failure analysis are described. The information obtained through RELTECH can be used to address standardization issues, through development of cost effective qualification and appropriate screening criteria, for inclusion into a commercial specification and the MIL-H-38534 general specification for hybrid microcircuits.

  12. 76 FR 16240 - Mandatory Reliability Standards for Interconnection Reliability Operating Limits

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-03-23

    ... system operating limits other than interconnection reliability operating limits. DATES: Effective Date.... Documented Methodology to Identify System 33 Operating Limit Information 3. Current Practices for the... for the reliability coordinator to monitor and analyze system operating limits (SOL) \\4\\ other...

  13. 75 FR 71613 - Mandatory Reliability Standards for Interconnection Reliability Operating Limits

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-11-24

    ... Energy Regulatory Commission 18 CFR Part 40 Mandatory Reliability Standards for Interconnection Reliability Operating Limits November 18, 2010. AGENCY: Federal Energy Regulatory Commission. ACTION: Notice... Regulatory Commission proposes to approve three new Interconnection Reliability Operations and...

  14. Impact of staffing parameters on operational reliability

    SciTech Connect

    Hahn, H.A.; Houghton, F.K.

    1993-02-01

    This paper reports on a project related to human resource management of the Department of Energy`s (DOE`s) High-Level Waste (HLW) Tank program. Safety and reliability of waste tank operations is impacted by several issues, including not only the design of the tanks themselves, but also how operations and operational personnel are managed. As demonstrated by management assessments performed by the Tiger Teams, DOE believes that the effective use of human resources impacts environment safety, and health concerns. For the of the current paper, human resource management activities are identified as ``Staffing`` and include the of developing the functional responsibilities and qualifications of technical and administrative personnel. This paper discusses the importance of staff plans and management in the overall view of safety and reliability. The work activities and procedures associated with the project, a review of the results of these activities, including a summary of the literature and a preliminary analysis of the data. We conclude that although identification of staffing issues and the development of staffing plans contributes to the overall reliability and safety of the HLW tanks, the relationship is not well understood and is in need of further development.

  15. Impact of staffing parameters on operational reliability

    SciTech Connect

    Hahn, H.A.; Houghton, F.K.

    1993-01-01

    This paper reports on a project related to human resource management of the Department of Energy's (DOE's) High-Level Waste (HLW) Tank program. Safety and reliability of waste tank operations is impacted by several issues, including not only the design of the tanks themselves, but also how operations and operational personnel are managed. As demonstrated by management assessments performed by the Tiger Teams, DOE believes that the effective use of human resources impacts environment safety, and health concerns. For the of the current paper, human resource management activities are identified as Staffing'' and include the of developing the functional responsibilities and qualifications of technical and administrative personnel. This paper discusses the importance of staff plans and management in the overall view of safety and reliability. The work activities and procedures associated with the project, a review of the results of these activities, including a summary of the literature and a preliminary analysis of the data. We conclude that although identification of staffing issues and the development of staffing plans contributes to the overall reliability and safety of the HLW tanks, the relationship is not well understood and is in need of further development.

  16. 76 FR 42534 - Mandatory Reliability Standards for Interconnection Reliability Operating Limits; System...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-07-19

    ... Reliability Operating Limits; System Restoration Reliability Standards AGENCY: Federal Energy Regulatory... necessary to analyze and monitor Interconnection Reliability Operating Limits (IROL) within its Wide-Area... Interconnection Reliability Operating Limits, Order No. 748, 134 FERC ] 61,213 (2011). \\2\\ The term...

  17. 18 CFR 292.308 - Standards for operating reliability.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... reliability. 292.308 Section 292.308 Conservation of Power and Water Resources FEDERAL ENERGY REGULATORY... Act of 1978 § 292.308 Standards for operating reliability. Any State regulatory authority (with... may establish reasonable standards to ensure system safety and reliability of...

  18. Distribution and reliability in a multiprocessor operating system

    SciTech Connect

    Sindhu, P.S.

    1984-01-01

    This thesis explores whether distributed hardware can be used to build reliable systems that are practical. It deals mostly with issues in the design and construction of the MEDUSA operating system, built to run of the distributed multiprocessor Cm. The goal is to exploit the redundancy, physical distribution, and powerful communication facilities within Cm to produce a robust system - one that can function satisfactorily in spite of hardware failure, bad data, heavy demands on its services, and other disruptive occurrences. The thesis demonstrates that, given appropriate hardware, it is possible to provide robustness without significantly sacrificing performance or greatly increasing complexity. Factors important to this success were 1) the treatment of reliability as a probabilistic rather than an absolute guarantee, which resulted in a structure whose components explicitly acknowledge and cope with failures in one another; 2) the adoption of a systematic approach to exception processing, which made the complexity of recovery manageable; and 3) the exploitation of system knowledge in the design of reliability mechanisms, which made it possible to achieve robustness while retaining good normal-case performance.

  19. Validity and Reliability of Trichotomous Achievement Goal Scale

    ERIC Educational Resources Information Center

    Ilker, Gokce Erturan; Arslan, Yunus; Demirhan, Giyasettin

    2011-01-01

    The Trichotomous Achievement Goal Scale was developed by Agbuga and Xiang (2008) by including selected items from the scales of Duda and Nicholls (1992), Elliot (1999), and Elliot and Church (1997) and adapting them into Turkish. The scale consists of 18 items, and students rated each item on a 7-point Likert scale. To ascertain the validity and…

  20. Fair and Just Culture, Team Behavior, and Leadership Engagement: The Tools to Achieve High Reliability

    PubMed Central

    Frankel, Allan S; Leonard, Michael W; Denham, Charles R

    2006-01-01

    Background Disparate health care provider attitudes about autonomy, teamwork, and administrative operations have added to the complexity of health care delivery and are a central factor in medicine's unacceptably high rate of errors. Other industries have improved their reliability by applying innovative concepts to interpersonal relationships and administrative hierarchical structures (Chandler 1962). In the last 10 years the science of patient safety has become more sophisticated, with practical concepts identified and tested to improve the safety and reliability of care. Objective Three initiatives stand out as worthy regarding interpersonal relationships and the application of provider concerns to shape operational change: The development and implementation of Fair and Just Culture principles, the broad use of Teamwork Training and Communication, and tools like WalkRounds that promote the alignment of leadership and frontline provider perspectives through effective use of adverse event data and provider comments. Methods Fair and Just Culture, Teamwork Training, and WalkRounds are described, and implementation examples provided. The argument is made that they must be systematically and consistently implemented in an integrated fashion. Conclusions There are excellent examples of institutions applying Just Culture principles, Teamwork Training, and Leadership WalkRounds—but to date, they have not been comprehensively instituted in health care organizations in a cohesive and interdependent manner. To achieve reliability, organizations need to begin thinking about the relationship between these efforts and linking them conceptually. PMID:16898986

  1. Operator adaptation to changes in system reliability under adaptable automation.

    PubMed

    Chavaillaz, Alain; Sauer, Juergen

    2016-11-25

    This experiment examined how operators coped with a change in system reliability between training and testing. Forty participants were trained for 3 h on a complex process control simulation modelling six levels of automation (LOA). In training, participants either experienced a high- (100%) or low-reliability system (50%). The impact of training experience on operator behaviour was examined during a 2.5 h testing session, in which participants either experienced a high- (100%) or low-reliability system (60%). The results showed that most operators did not often switch between LOA. Most chose an LOA that relieved them of most tasks but maintained their decision authority. Training experience did not have a strong impact on the outcome measures (e.g. performance, complacency). Low system reliability led to decreased performance and self-confidence. Furthermore, complacency was observed under high system reliability. Overall, the findings suggest benefits of adaptable automation because it accommodates different operator preferences for LOA. Practitioner Summary: The present research shows that operators can adapt to changes in system reliability between training and testing sessions. Furthermore, it provides evidence that each operator has his/her preferred automation level. Since this preference varies strongly between operators, adaptable automation seems to be suitable to accommodate these large differences.

  2. Desert ants achieve reliable recruitment across noisy interactions.

    PubMed

    Razin, Nitzan; Eckmann, Jean-Pierre; Feinerman, Ofer

    2013-05-06

    We study how desert ants, Cataglyphis niger, a species that lacks pheromone-based recruitment mechanisms, inform each other about the presence of food. Our results are based on automated tracking that allows us to collect a large database of ant trajectories and interactions. We find that interactions affect an ant's speed within the nest. Fast ants tend to slow down, whereas slow ones increase their speed when encountering a faster ant. Faster ants tend to exit the nest more frequently than slower ones. So, if an ant gains enough speed through encounters with others, then she tends to leave the nest and look for food. On the other hand, we find that the probability for her to leave the nest depends only on her speed, but not on whether she had recently interacted with a recruiter that has found the food. This suggests a recruitment system in which ants communicate their state by very simple interactions. Based on this assumption, we estimate the information-theoretical channel capacity of the ants' pairwise interactions. We find that the response to the speed of an interacting nest-mate is very noisy. The question is then how random interactions with ants within the nest can be distinguished from those interactions with a recruiter who has found food. Our measurements and model suggest that this distinction does not depend on reliable communication but on behavioural differences between ants that have found the food and those that have not. Recruiters retain high speeds throughout the experiment, regardless of the ants they interact with; non-recruiters communicate with a limited number of nest-mates and adjust their speed following these interactions. These simple rules lead to the formation of a bistable switch on the level of the group that allows the distinction between recruitment and random noise in the nest. A consequence of the mechanism we propose is a negative effect of ant density on exit rates and recruitment success. This is, indeed, confirmed by our

  3. Process validation: achieving the Operational Qualification phase.

    PubMed

    Buffaloe, Vera

    2004-01-01

    The OQ phase of process validation is very important and is where the complete understanding of the process is determined by experimentation. This understanding is useful to: * establish optimal process parameters * understand variation that affect the process * aid in investigating process deviations. OQ is an important part of the entire process validation activity and essential to understanding a manufacturing process. The benefits of completing the OQ and overall process validation are the reasons that it makes business sense and receive the long-term benefits of producing high quality product and achieving customer satisfaction.

  4. Challenges in Achieving Trajectory-Based Operations

    NASA Technical Reports Server (NTRS)

    Cate, Karen Tung

    2012-01-01

    In the past few years much of the global ATM research community has proposed advanced systems based on Trajectory-Based Operations (TBO). The concept of TBO uses four-dimensional aircraft trajectories as the base information for managing safety and capacity. Both the US and European advanced ATM programs call for the sharing of trajectory data across different decision support tools for successful operations. However, the actual integration of TBO systems presents many challenges. Trajectory predictors are built to meet the specific needs of a particular system and are not always compatible with others. Two case studies are presented which examine the challenges of introducing a new concept into two legacy systems in regards to their trajectory prediction software. The first case describes the issues with integrating a new decision support tool with a legacy operational system which overlap in domain space. These tools perform similar functions but are driven by different requirements. The difference in the resulting trajectories can lead to conflicting advisories. The second case looks at integrating this same new tool with a legacy system originally developed as an integrated system, but diverged many years ago. Both cases illustrate how the lack of common architecture concepts for the trajectory predictors added cost and complexity to the integration efforts.

  5. Technical information report: Plasma melter operation, reliability, and maintenance analysis

    SciTech Connect

    Hendrickson, D.W.

    1995-03-14

    This document provides a technical report of operability, reliability, and maintenance of a plasma melter for low-level waste vitrification, in support of the Hanford Tank Waste Remediation System (TWRS) Low-Level Waste (LLW) Vitrification Program. A process description is provided that minimizes maintenance and downtime and includes material and energy balances, equipment sizes and arrangement, startup/operation/maintence/shutdown cycle descriptions, and basis for scale-up to a 200 metric ton/day production facility. Operational requirements are provided including utilities, feeds, labor, and maintenance. Equipment reliability estimates and maintenance requirements are provided which includes a list of failure modes, responses, and consequences.

  6. Development of Achievement Test: Validity and Reliability Study for Achievement Test on Matter Changing

    ERIC Educational Resources Information Center

    Kara, Filiz; Celikler, Dilek

    2015-01-01

    For "Matter Changing" unit included in the Secondary School 5th Grade Science Program, it is intended to develop a test conforming the gains described in the program, and that can determine students' achievements. For this purpose, a multiple-choice test of 48 questions is arranged, consisting of 8 questions for each gain included in the…

  7. Factors that Affect Operational Reliability of Turbojet Engines

    NASA Technical Reports Server (NTRS)

    1956-01-01

    The problem of improving operational reliability of turbojet engines is studied in a series of papers. Failure statistics for this engine are presented, the theory and experimental evidence on how engine failures occur are described, and the methods available for avoiding failure in operation are discussed. The individual papers of the series are Objectives, Failure Statistics, Foreign-Object Damage, Compressor Blades, Combustor Assembly, Nozzle Diaphrams, Turbine Buckets, Turbine Disks, Rolling Contact Bearings, Engine Fuel Controls, and Summary Discussion.

  8. SLAC modulator operation and reliability in the SLC Era

    SciTech Connect

    Donaldson, A.R.; Ashton, J.R.

    1992-06-01

    A discussion of the operation and reliability of the 244 modulators in the SLAC linac with an emphasis on the past three years of operation. The linac modulators were designed and built in the 60's, upgraded for the SLAC Linear Collider (SLC) in the mid 80s, and despite their age are still reliable accelerator components. The 60s modulator operated at 65 MW peak and 83 kW average power. The upgrade resulted in 150 MW peak output at an average power of 87 kW, a modest increase since the repetition rate was dropped from 360 to 120 Hz. In the present accelerator configuration, the Linac operates as a source of electrons and positrons to a single pass coillider. The classic collider is a storage ring filled with oppositely charged, counter-rotating particles which are allowed to collide until an accelerator fault occurs and the stored beams are aborted. A reasonable storage ring can store and collide particles for as long as eight hours with a 10 or 20 minute filling time. A single pass collider, + on the other hand, can only produce e{sup {minus}} and e{sup +} collisions at whatever rate the source operates. To be effective the SLC must operate at 120 Hz with a very high degree of reliability and on a continuous basis. Fortunately, the linac has a modest excess of modulator/klystron systems which allows some measure of redundancy and hence some freedom from the constraint that all 244 modulator/klystrons operate simultaneously. Nonetheless, high importance is placed on modulator MTBF and MTRR or, in the parlance of reliability experts and accelerator physicists, availability. This is especially true of the modulators associated with the fundamental requirements of a collider such as injection, compression and positron production.

  9. SLAC modulator operation and reliability in the SLC Era

    SciTech Connect

    Donaldson, A.R.; Ashton, J.R.

    1992-06-01

    A discussion of the operation and reliability of the 244 modulators in the SLAC linac with an emphasis on the past three years of operation. The linac modulators were designed and built in the 60`s, upgraded for the SLAC Linear Collider (SLC) in the mid 80s, and despite their age are still reliable accelerator components. The 60s modulator operated at 65 MW peak and 83 kW average power. The upgrade resulted in 150 MW peak output at an average power of 87 kW, a modest increase since the repetition rate was dropped from 360 to 120 Hz. In the present accelerator configuration, the Linac operates as a source of electrons and positrons to a single pass coillider. The classic collider is a storage ring filled with oppositely charged, counter-rotating particles which are allowed to collide until an accelerator fault occurs and the stored beams are aborted. A reasonable storage ring can store and collide particles for as long as eight hours with a 10 or 20 minute filling time. A single pass collider, + on the other hand, can only produce e{sup {minus}} and e{sup +} collisions at whatever rate the source operates. To be effective the SLC must operate at 120 Hz with a very high degree of reliability and on a continuous basis. Fortunately, the linac has a modest excess of modulator/klystron systems which allows some measure of redundancy and hence some freedom from the constraint that all 244 modulator/klystrons operate simultaneously. Nonetheless, high importance is placed on modulator MTBF and MTRR or, in the parlance of reliability experts and accelerator physicists, availability. This is especially true of the modulators associated with the fundamental requirements of a collider such as injection, compression and positron production.

  10. Spaceflight tracking and data network operational reliability assessment for Skylab

    NASA Technical Reports Server (NTRS)

    Seneca, V. I.; Mlynarczyk, R. H.

    1974-01-01

    Data on the spaceflight communications equipment status during the Skylab mission were subjected to an operational reliability assessment. Reliability models were revised to reflect pertinent equipment changes accomplished prior to the beginning of the Skylab missions. Appropriate adjustments were made to fit the data to the models. The availabilities are based on the failure events resulting in the stations inability to support a function of functions and the MTBF's are based on all events including 'can support' and 'cannot support'. Data were received from eleven land-based stations and one ship.

  11. ADVANCED COMPRESSOR ENGINE CONTROLS TO ENHANCE OPERATION, RELIABILITY AND INTEGRITY

    SciTech Connect

    Gary D. Bourn; Jess W. Gingrich; Jack A. Smith

    2004-03-01

    This document is the final report for the ''Advanced Compressor Engine Controls to Enhance Operation, Reliability, and Integrity'' project. SwRI conducted this project for DOE in conjunction with Cooper Compression, under DOE contract number DE-FC26-03NT41859. This report addresses an investigation of engine controls for integral compressor engines and the development of control strategies that implement closed-loop NOX emissions feedback.

  12. ANALYSIS OF AVAILABILITY AND RELIABILITY IN RHIC OPERATIONS.

    SciTech Connect

    PILAT, F.; INGRASSIA, P.; MICHNOFF, R.

    2006-06-26

    RHIC has been successfully operated for 5 years as a collider for different species, ranging from heavy ions including gold and copper, to polarized protons. We present a critical analysis of reliability data for RHIC that not only identifies the principal factors limiting availability but also evaluates critical choices at design times and assess their impact on present machine performance. RHIC availability data are typical when compared to similar high-energy colliders. The critical analysis of operations data is the basis for studies and plans to improve RHIC machine availability beyond the 50-60% typical of high-energy colliders.

  13. 76 FR 58101 - Electric Reliability Organization Interpretation of Transmission Operations Reliability Standard

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-09-20

    ... of Reliability Standard, TOP-001-1, Requirement R8, which pertains to the restoration of real and... Requirement R8 in Commission-approved NERC Reliability Standard TOP-001-1-- Reliability Responsibilities and... 107 Reliability Standards filed by NERC, including Reliability Standard TOP-001-1.\\4\\ \\2\\...

  14. ASTER system operating achievement for 15 years on orbit

    NASA Astrophysics Data System (ADS)

    Inada, Hitomi; Ito, Yoshiyuki; Kikuchi, Masakuni; Sakuma, Fumihiro; Tatsumi, Kenji; Akagi, Shigeki; Ono, Hidehiko

    2015-10-01

    ASTER (Advanced Spaceborne Thermal Emission and Reflection Radiometer) System is operating more than 15 years since launched on board of NASA's Terra spacecraft in December 1999. ASTER System is composed of 3 radiometers (VNIR (Visible and Near Infrared Radiometer), SWIR (Short-Wave Infrared Radiometer), and TIR (Thermal Infrared Radiometer)), CSP (Common Signal Processor) and MSP (Master Power Supply). This paper describes the ASTER System operating history and the achievement of ASTER System long term operation since the initial checkout operation, the normal operation, and the continuous operation. Through the 15 years operation, ASTER system had totally checked the all subsystems (MPS, VNIR, TIR, SWIR, and CSP) health and safety check using telemetry data trend evaluation, and executed the necessary action. The watch items are monitored as the life control items. The pointing mechanics for VNIR, SWIR and TIR, and the cooler for SWIR and TIR are all operating with any problem for over 15 years. In 2003, ASTER was successfully operated for the lunar calibration. As the future plan, ASTER team is proposing the 2nd lunar calibration before the end of mission.

  15. ICAROUS - Integrated Configurable Algorithms for Reliable Operations Of Unmanned Systems

    NASA Technical Reports Server (NTRS)

    Consiglio, María; Muñoz, César; Hagen, George; Narkawicz, Anthony; Balachandran, Swee

    2016-01-01

    NASA's Unmanned Aerial System (UAS) Traffic Management (UTM) project aims at enabling near-term, safe operations of small UAS vehicles in uncontrolled airspace, i.e., Class G airspace. A far-term goal of UTM research and development is to accommodate the expected rise in small UAS traffic density throughout the National Airspace System (NAS) at low altitudes for beyond visual line-of-sight operations. This paper describes a new capability referred to as ICAROUS (Integrated Configurable Algorithms for Reliable Operations of Unmanned Systems), which is being developed under the UTM project. ICAROUS is a software architecture comprised of highly assured algorithms for building safety-centric, autonomous, unmanned aircraft applications. Central to the development of the ICAROUS algorithms is the use of well-established formal methods to guarantee higher levels of safety assurance by monitoring and bounding the behavior of autonomous systems. The core autonomy-enabling capabilities in ICAROUS include constraint conformance monitoring and contingency control functions. ICAROUS also provides a highly configurable user interface that enables the modular integration of mission-specific software components.

  16. 76 FR 23222 - Electric Reliability Organization Interpretation of Transmission Operations Reliability

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-04-26

    ...) proposed interpretation of Reliability Standard, TOP-001-1, Requirement R8. DATES: Comments are due June 27... Requirement R8 in Commission-approved NERC Reliability Standard TOP-001-1 -- Reliability Responsibilities and... by NERC, including Reliability Standard TOP-001-1.\\5\\ \\3\\ Rules Concerning Certification of...

  17. PLATEAUING COSMIC RAY DETECTORS TO ACHIEVE OPTIMUM OPERATING VOLTAGE

    SciTech Connect

    Knoff, E.N.; Peterson, R.S.

    2008-01-01

    Through QuarkNet, students across the country have access to cosmic ray detectors in their high school classrooms. These detectors operate using a scintillator material and a photomultiplier tube (PMT). A data acquisition (DAQ) board counts cosmic ray hits from the counters. Through an online e-Lab, students can analyze and share their data. In order to collect viable data, the PMTs should operate at their plateau voltages. In these plateau ranges, the number of counts per minute remains relatively constant with small changes in PMT voltage. We sought to plateau the counters in the test array and to clarify the plateauing procedure itself. In order to most effectively plateau the counters, the counters should be stacked and programmed to record the number of coincident hits as well as their singles rates. We also changed the threshold value that a signal must exceed in order to record a hit and replateaued the counters. For counter 1, counter 2, and counter 3, we found plateau voltages around 1V. The singles rate plateau was very small, while the coincidence plateau was very long. The plateau voltages corresponded to a singles rate of 700–850 counts per minute. We found very little effect of changing the threshold voltages. Our chosen plateau voltages produced good performance studies on the e-Lab. Keeping in mind the nature of the experiments conducted by the high school students, we recommend a streamlined plateauing process. Because changing the threshold did not drastically affect the plateau voltage or the performance study, students should choose a threshold value, construct plateau graphs, and analyze their data using a performance study. Even if the counters operate slightly off their plateau voltage, they should deliver good performance studies and return reliable results.

  18. The Interim: Until You Achieve an Operationally Responsive Ground System

    NASA Technical Reports Server (NTRS)

    Wendlandt, Bob; Clarke, Kelly; Miyamoto, Charles; Lei, Jordan; Owen-Mankovich, Kyran

    2008-01-01

    Everyone wants to achieve a 'Responsive' Ground Data System (GDS), but that takes time. What do you do in the interim? Our group, called the Integration, Test and Deployment Team (ITD), is a group of responsive engineers whose primary focus is to assist JPL projects to successfully adapt, test, integrate and deploy their ground data system. The team configures and adapts the GDS for a project, so that analysts, engineers and scientist do not need to be experts in the GDS to operate it. The team has developed a human interface to accommodate all types of users. It provides Graphical User Interfaces (GUI's) for those that want GUI's, command line interfaces for those that want control, and selection button interfaces for other users. The cornerstone of a responsive Ground Data System is responsive people. Without individuals who can be aware of a project's changing needs and requirements, how can the GDS become responsive?.

  19. The Interim : until you achieve an operationally responsive ground system

    NASA Technical Reports Server (NTRS)

    Wendlandt, Bob; Clarke, Kelly; Lei, Jordan; Miyamoto, Charles; Owen-Mankovich, Kyran

    2008-01-01

    Everyone wants to achieve a 'Responsive' Ground Data System (GDS), but that takes time. What do you do in the interim? Our group, called the Integration, Test and Deployment Team (ITD), is a group of responsive engineers whose primary focus is to assist JPL projects to successfully adapt, test, integrate and deploy their ground data system. The team configures and adapts the GDS for a project, so that analysts, engineers and scientist do not need to be experts in the GDS to operate it. The team has developed a human interface to accommodate all types of users. It provides Graphical User Interfaces (GUI's) for those that want GUI's, command line interfaces for those that want control, and selection button interfaces for other users. The cornerstone of a responsive Ground Data System is responsive people. Without individuals who can be aware of a project's changing needs and requirements, how can the GDS become responsive

  20. Remotely Operated Vehicle ROV/AUV Reliability Study. Phase 2.

    DTIC Science & Technology

    1989-09-01

    Cable Connectors for Deep Ocean Applications . Port Hueneme, CA: Civil Engineering Lab., Naval Construction Battalion Center, Technical Report R806...competition. As a result, commercial- grade vehicles with broad applications are modified for specific requirements. These vehicles have reliability and other...Navy’s use of commercial grade broad application vehicles that have been modified for specific requirements. Long term reliability is not a design

  1. Nuclear electric propulsion operational reliability and crew safety study: NEP systems/modeling report

    NASA Technical Reports Server (NTRS)

    Karns, James

    1993-01-01

    The objective of this study was to establish the initial quantitative reliability bounds for nuclear electric propulsion systems in a manned Mars mission required to ensure crew safety and mission success. Finding the reliability bounds involves balancing top-down (mission driven) requirements and bottom-up (technology driven) capabilities. In seeking this balance we hope to accomplish the following: (1) provide design insights into the achievability of the baseline design in terms of reliability requirements, given the existing technology base; (2) suggest alternative design approaches which might enhance reliability and crew safety; and (3) indicate what technology areas require significant research and development to achieve the reliability objectives.

  2. DG Planning with Amalgamation of Operational and Reliability Considerations

    NASA Astrophysics Data System (ADS)

    Battu, Neelakanteshwar Rao; Abhyankar, A. R.; Senroy, Nilanjan

    2016-04-01

    Distributed Generation has been playing a vital role in dealing issues related to distribution systems. This paper presents an approach which provides policy maker with a set of solutions for DG placement to optimize reliability and real power loss of the system. Optimal location of a Distributed Generator is evaluated based on performance indices derived for reliability index and real power loss. The proposed approach is applied on a 15-bus radial distribution system and a 18-bus radial distribution system with conventional and wind distributed generators individually.

  3. Magnetically operated limit switch has improved reliability, minimizes arcing

    NASA Technical Reports Server (NTRS)

    Steiner, R.

    1966-01-01

    Limit switch for reliable, low-travel, snap action with negligible arcing uses an electrically nonconductive permanent magnet consisting of a ferrimagnetic ceramic and ferromagnetic pole shoes which form a magnetic and electrically conductive circuit with a ferrous-metal armature.

  4. 76 FR 23171 - Electric Reliability Organization Interpretations of Interconnection Reliability Operations and...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-04-26

    ... will result in the failure of the Special Protection System to operate as designed. DATES: Effective... neighboring systems upon request, or when the loss of the communication channel will result in the failure of... Protection System including any degradation or potential failure to operate as expected. 2....

  5. The Stories Clinicians Tell: Achieving High Reliability and Improving Patient Safety

    PubMed Central

    Cohen, Daniel L; Stewart, Kevin O

    2016-01-01

    The patient safety movement has been deeply affected by the stories patients have shared that have identified numerous opportunities for improvements in safety. These stories have identified system and/or human inefficiencies or dysfunctions, possibly even failures, often resulting in patient harm. Although patients’ stories tell us much, less commonly heard are the stories of clinicians and how their personal observations regarding the environments they work in and the circumstances and pressures under which they work may degrade patient safety and lead to harm. If the health care industry is to function like a high-reliability industry, to improve its processes and achieve the outcomes that patients rightly deserve, then leaders and managers must seek and value input from those on the front lines—both clinicians and patients. Stories from clinicians provided in this article address themes that include incident identification, disclosure and transparency, just culture, the impact of clinical workload pressures, human factors liabilities, clinicians as secondary victims, the impact of disruptive and punitive behaviors, factors affecting professional morale, and personal failings. PMID:26580146

  6. How Long Can the Hubble Space Telescope Operate Reliably?

    NASA Technical Reports Server (NTRS)

    Xapsos, M. A.; Stauffer, C.; Jordan, T.; Poivey, C.; Lum, G.; Haskins, D. N.; Pergosky, A. M.; Smith, D. C.; LaBel, K. A.

    2014-01-01

    Total ionizing dose exposure of electronic parts in the Hubble Space Telescope is analyzed using 3-D ray trace and Monte Carlo simulations. Results are discussed along with other potential failure mechanisms for science operations.

  7. WEF/WERF study of BNR plants achieving very low N and P limits: evaluation of technology performance and process reliability.

    PubMed

    Bott, Charles B; Parker, Denny S; Jimenez, Jose; Miller, Mark W; Neethling, J B

    2012-01-01

    The Water Environment Research Foundation (WERF) funded a two-year comprehensive study of nutrient removal plants designed and operated to meet very low effluent total nitrogen (TN) and total phosphorus (TP) concentrations. WERF worked with the Water Environment Federation (WEF) to solicit participation of volunteers and provide a forum for information exchange at workshops at its annual conferences. Both existing and new technologies are being adapted to meet requirements that are as low as 3.0 mg/L TN and 0.1 mg/L TP, and there is a need to define their capabilities and reliabilities in the real world situation of wastewater treatment plants. A concern over very low daily permits for ammonia caused the work to be extended to include nitrification reliability. This effort focused on maximizing what can be learned from existing technologies in order to provide a database that will inform key decision makers about proper choices for both technologies and rationale bases for statistical permit writing. To this end, managers of 22 plants, 10 achieving low effluent TP, nine achieving low effluent TN, and three achieving low effluent NH(3)-N, provided three years of operational data that were analyzed using a consistent statistical approach. Technology Performance Statistics (TPSs) were developed as three separate values representing the ideal, median, and reliably achievable performance. Technological conclusions can be drawn from the study in terms of what can be learned by comparing the different nutrient removal and nitrification processes employed at these 22 plants.

  8. Balancing low cost with reliable operation in the rotordynamic design of the ALS Liquid Hydrogen Fuel Turbopump

    NASA Technical Reports Server (NTRS)

    Greenhill, L. M.

    1990-01-01

    The Air Force/NASA Advanced Launch System (ALS) Liquid Hydrogen Fuel Turbopump (FTP) has primary design goals of low cost and high reliability, with performance and weight having less importance. This approach is atypical compared with other rocket engine turbopump design efforts, such as on the Space Shuttle Main Engine (SSME), which emphasized high performance and low weight. Similar to the SSME turbopumps, the ALS FTP operates supercritically, which implies that stability and bearing loads strongly influence the design. In addition, the use of low cost/high reliability features in the ALS FTP such as hydrostatic bearings, relaxed seal clearances, and unshrouded turbine blades also have a negative influence on rotordynamics. This paper discusses the analysis conducted to achieve a balance between low cost and acceptable rotordynamic behavior, to ensure that the ALS FTP will operate reliably without subsynchronous instabilities or excessive bearing loads.

  9. The reliability analysis of a separated, dual fail operational redundant strapdown IMU. [inertial measurement unit

    NASA Technical Reports Server (NTRS)

    Motyka, P.

    1983-01-01

    A methodology for quantitatively analyzing the reliability of redundant avionics systems, in general, and the dual, separated Redundant Strapdown Inertial Measurement Unit (RSDIMU), in particular, is presented. The RSDIMU is described and a candidate failure detection and isolation system presented. A Markov reliability model is employed. The operational states of the system are defined and the single-step state transition diagrams discussed. Graphical results, showing the impact of major system parameters on the reliability of the RSDIMU system, are presented and discussed.

  10. Resource reliability, accessibility and governance: pillars for managing water resources to achieve water security in Nepal

    NASA Astrophysics Data System (ADS)

    Biggs, E. M.; Duncan, J.; Atkinson, P.; Dash, J.

    2013-12-01

    As one of the world's most water-abundant countries, Nepal has plenty of water yet resources are both spatially and temporally unevenly distributed. With a population heavily engaged in subsistence farming, whereby livelihoods are entirely dependent on rain-fed agriculture, changes in freshwater resources can substantially impact upon survival. The two main sources of water in Nepal come from monsoon precipitation and glacial runoff. The former is essential for sustaining livelihoods where communities have little or no access to perennial water resources. Much of Nepal's population live in the southern Mid-Hills and Terai regions where dependency on the monsoon system is high and climate-environment interactions are intricate. Any fluctuations in precipitation can severely affect essential potable resources and food security. As the population continues to expand in Nepal, and pressures build on access to adequate and clean water resources, there is a need for institutions to cooperate and increase the effectiveness of water management policies. This research presents a framework detailing three fundamental pillars for managing water resources to achieve sustainable water security in Nepal. These are (i) resource reliability; (ii) adequate accessibility; and (iii) effective governance. Evidence is presented which indicates that water resources are adequate in Nepal to sustain the population. In addition, aspects of climate change are having less impact than previously perceived e.g. results from trend analysis of precipitation time-series indicate a decrease in monsoon extremes and interannual variation over the last half-century. However, accessibility to clean water resources and the potential for water storage is limiting the use of these resources. This issue is particularly prevalent given the heterogeneity in spatial and temporal distributions of water. Water governance is also ineffective due to government instability and a lack of continuity in policy

  11. 76 FR 23470 - Version One Regional Reliability Standard for Transmission Operations

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-04-27

    ... Reliability Standard TOP-007-WECC-1 (System Operating Limits) developed by the Western Electric Coordinating... associated scheduled flows on major WECC transfer paths do not exceed system operating limits for more than... TOP-007-WECC-1 (System Operating Limits) developed by the Western Electricity Coordinating...

  12. Achieving Unity of Effort: A Challenge in Domestic Support Operations.

    DTIC Science & Technology

    2007-11-02

    active duty soldiers and 13,376 National Guard soldiers from 47 states and territories in support of the Olympic and Paralympic Games. There was no...Olympic and Paralympic area of operations to support the federal response to a major disaster or terrorist incident involving WMD in Alabama...Olympic and Paralympic Games Contingency Operations," presented at the DOD Emergency Preparedness Course 97-01,1 Nov 97. Hereafter cited as Steinmetz

  13. Using Information from Operating Experience to Inform Human Reliability Analysis

    SciTech Connect

    Bruce P. Hallbert; David I. Gertman; Julie Marble; Erasmia Lois; Nathan Siu

    2004-06-01

    This paper reports on efforts being sponsored by the U.S. NRC and performed by INEEL to develop a technical basis and perform work to extract information from sources for use in HRA. The objectives of this work are to: 1) develop a method for conducting risk-informed event analysis of human performance information that stems from operating experience at nuclear power plants and for compiling and documenting the results in a structured manner; 2) provide information from these analyses for use in risk-informed and performance-based regulatory activities; 3) create methods for information extraction and a repository for this information that, likewise, support HRA methods and their applications.

  14. Reliability of High Power Laser Diode Arrays Operating in Long Pulse Mode

    NASA Technical Reports Server (NTRS)

    Amzajerdian, Farzin; Meadows, Byron L.; Barnes, Bruce W.; Lockard, George E.; Singh, Upendra N.; Kavaya, Michael J.; Baker, Nathaniel R.

    2006-01-01

    Reliability and lifetime of quasi-CW laser diode arrays are greatly influenced by their thermal characteristics. This paper examines the thermal properties of laser diode arrays operating in long pulse duration regime.

  15. Updating the reference population to achieve constant genomic prediction reliability across generations.

    PubMed

    Pszczola, M; Calus, M P L

    2016-06-01

    The reliability of genomic breeding values (DGV) decays over generations. To keep the DGV reliability at a constant level, the reference population (RP) has to be continuously updated with animals from new generations. Updating RP may be challenging due to economic reasons, especially for novel traits involving expensive phenotyping. Therefore, the goal of this study was to investigate a minimal RP update size to keep the reliability at a constant level across generations. We used a simulated dataset resembling a dairy cattle population. The trait of interest was not included itself in the selection index, but it was affected by selection pressure by being correlated with an index trait that represented the overall breeding goal. The heritability of the index trait was assumed to be 0.25 and for the novel trait the heritability equalled 0.2. The genetic correlation between the two traits was 0.25. The initial RP (n=2000) was composed of cows only with a single observation per animal. Reliability of DGV using the initial RP was computed by evaluating contemporary animals. Thereafter, the RP was used to evaluate animals which were one generation younger from the reference individuals. The drop in the reliability when evaluating younger animals was then assessed and the RP was updated to re-gain the initial reliability. The update animals were contemporaries of evaluated animals (EVA). The RP was updated in batches of 100 animals/update. First, the animals most closely related to the EVA were chosen to update RP. The results showed that, approximately, 600 animals were needed every generation to maintain the DGV reliability at a constant level across generations. The sum of squared relationships between RP and EVA and the sum of off-diagonal coefficients of the inverse of the genomic relationship matrix for RP, separately explained 31% and 34%, respectively, of the variation in the reliability across generations. Combined, these parameters explained 53% of the

  16. Is "School Achievement" Enhanced by Teaching Children Operational Concepts?

    ERIC Educational Resources Information Center

    Bearison, David J.

    Several curricula for early childhood education rely heavily upon Piagetian theory, based on the reasoning that children who have acquired operational structures of thought one or two years earlier than their peers are differently oriented to instruction than their more recently conserving peers. This paper emphasizes that there is no evidence…

  17. Inspiration, Perspiration, and Time: Operations and Achievement in Edison Schools

    ERIC Educational Resources Information Center

    Gill, Brian P.; Hamilton, Laura S.; Lockwood, J. R.; Marsh, Julie A.; Zimmer, Ron W.; Hill, Deanna; Pribesh, Shana

    2005-01-01

    New forms of governing and managing public schools have proliferated in recent years, spawning the establishment and growth of companies that operate public schools under contract. Among these education management organizations, or EMOs, the largest and most visible is Edison Schools, Inc., with a nationwide network in 2004-2005 of 103 managed…

  18. Is It Really Possible to Test All Educationally Significant Achievements with High Levels of Reliability?

    ERIC Educational Resources Information Center

    Davis, Andrew

    2015-01-01

    PISA claims that it can extend its reach from its current core subjects of Reading, Science, Maths and problem-solving. Yet given the requirement for high levels of reliability for PISA, especially in the light of its current high stakes character, proposed widening of its subject coverage cannot embrace some important aspects of the social and…

  19. Independent transmission system operators and their role in maintaining reliability in a restructured electric power industry

    SciTech Connect

    1998-01-01

    This report summarizes the current status of proposals to form Independent System Operators (ISOs) to operate high-voltage transmission systems in the United States and reviews their potential role in maintaining bulk power system reliability. As background information, the likely new industry structure, nature of deregulated markets, and institutional framework for bulk power system reliability are reviewed. The report identifies issues related to the formation of ISOs and their roles in markets and in reliability, and describes potential policy directions for encouraging the formation of effective ISOs and ensuring bulk system reliability. Two appendices are provided, which address: (1) system operation arrangements in other countries, and (2) summaries of regional U.S. ISO proposals.

  20. Reliability and Validity of the "Achievement Emotions Questionnaire": A Study of Argentinean University Students

    ERIC Educational Resources Information Center

    Paoloni, Paola Verónica; Vaja, Arabela Beatriz; Muñoz, Verónica Lilian

    2014-01-01

    Introduction: This paper aims at describing the psychometric features of the Achievement Emotions Questionnaire (AEQ), focusing specifically on the section that measures class emotions. From a theoretical perspective, this instrument was designed based on the control-value theory of achievement emotions. Therefore, a description of the…

  1. Kosovo Armed Forces Development; Achieving NATO Non-Article 5 Crisis Response Operations Interoperability

    DTIC Science & Technology

    2014-12-12

    KOSOVO ARMED FORCES DEVELOPMENT; ACHIEVING NATO NON-ARTICLE 5 CRISIS RESPONSE OPERATIONS INTEROPERABILITY A thesis presented...Achieving NATO Non- Article 5 Crisis Response Operations Interoperability 5a. CONTRACT NUMBER 5b. GRANT NUMBER 5c. PROGRAM ELEMENT NUMBER 6...interoperable and effective in NATO-led Crisis Response Operations. Therefore, this study focuses in examining current Kosovo Armed Forces development program

  2. Achieving cost reductions in EOSDIS operations through technology evolution

    NASA Technical Reports Server (NTRS)

    Newsome, Penny; Moe, Karen; Harberts, Robert

    1996-01-01

    The earth observing system (EOS) data information system (EOSDIS) mission includes the cost-effective management and distribution of large amounts of data to the earth science community. The effect of the introduction of new information system technologies on the evolution of EOSDIS is considered. One of the steps taken by NASA to enable the introduction of new information system technologies into the EOSDIS is the funding of technology development through prototyping. Recent and ongoing prototyping efforts and their potential impact on the performance and cost-effectiveness of the EOSDIS are discussed. The technology evolution process as it related to the effective operation of EOSDIS is described, and methods are identified for the support of the transfer of relevant technology to EOSDIS components.

  3. Laser welding of automotive aluminum alloys to achieve defect-free, structurally sound and reliable welds

    SciTech Connect

    DebRoy, T.

    2000-11-17

    The objective of this program was to seek improved process control and weldment reliability during laser welding of automotive aluminum alloys while retaining the high speed and accuracy of the laser beam welding process. The effects of various welding variables on the loss of alloying elements and the formation of porosity and other geometric weld defects such as underfill and overfill were studied both experimentally and theoretically.

  4. A study of the longevity and operational reliability of Goddard Spacecraft, 1960-1980

    NASA Technical Reports Server (NTRS)

    Shockey, E. F.

    1981-01-01

    Compiled data regarding the design lives and lifetimes actually achieved by 104 orbiting satellites launched by the Goddard Spaceflight Center between the years 1960 and 1980 is analyzed. Historical trends over the entire 21 year period are reviewed, and the more recent data is subjected to an examination of several key parameters. An empirical reliability function is derived, and compared with various mathematical models. Data from related studies is also discussed. The results provide insight into the reliability history of Goddard spacecraft an guidance for estimating the reliability of future programs.

  5. Operation Reliability Assessment for Cutting Tools by Applying a Proportional Covariate Model to Condition Monitoring Information

    PubMed Central

    Cai, Gaigai; Chen, Xuefeng; Li, Bing; Chen, Baojia; He, Zhengjia

    2012-01-01

    The reliability of cutting tools is critical to machining precision and production efficiency. The conventional statistic-based reliability assessment method aims at providing a general and overall estimation of reliability for a large population of identical units under given and fixed conditions. However, it has limited effectiveness in depicting the operational characteristics of a cutting tool. To overcome this limitation, this paper proposes an approach to assess the operation reliability of cutting tools. A proportional covariate model is introduced to construct the relationship between operation reliability and condition monitoring information. The wavelet packet transform and an improved distance evaluation technique are used to extract sensitive features from vibration signals, and a covariate function is constructed based on the proportional covariate model. Ultimately, the failure rate function of the cutting tool being assessed is calculated using the baseline covariate function obtained from a small sample of historical data. Experimental results and a comparative study show that the proposed method is effective for assessing the operation reliability of cutting tools. PMID:23201980

  6. Operation reliability assessment for cutting tools by applying a proportional covariate model to condition monitoring information.

    PubMed

    Cai, Gaigai; Chen, Xuefeng; Li, Bing; Chen, Baojia; He, Zhengjia

    2012-09-25

    The reliability of cutting tools is critical to machining precision and production efficiency. The conventional statistic-based reliability assessment method aims at providing a general and overall estimation of reliability for a large population of identical units under given and fixed conditions. However, it has limited effectiveness in depicting the operational characteristics of a cutting tool. To overcome this limitation, this paper proposes an approach to assess the operation reliability of cutting tools. A proportional covariate model is introduced to construct the relationship between operation reliability and condition monitoring information. The wavelet packet transform and an improved distance evaluation technique are used to extract sensitive features from vibration signals, and a covariate function is constructed based on the proportional covariate model. Ultimately, the failure rate function of the cutting tool being assessed is calculated using the baseline covariate function obtained from a small sample of historical data. Experimental results and a comparative study show that the proposed method is effective for assessing the operation reliability of cutting tools.

  7. Quantifying the Operational Benefits of Conventional and Advanced Pumped Storage Hydro on Reliability and Efficiency: Preprint

    SciTech Connect

    Krad, I.; Ela, E.; Koritarov, V.

    2014-07-01

    Pumped storage hydro (PSH) plants have significant potential to provide reliability and efficiency benefits in future electric power systems with high penetrations of variable generation. New PSH technologies, such as adjustable-speed PSH, have been introduced that can also present further benefits. This paper demonstrates and quantifies some of the reliability and efficiency benefits afforded by PSH plants by utilizing the Flexible Energy Scheduling Tool for the Integration of Variable generation (FESTIV), an integrated power system operations tool that evaluates both reliability and production costs.

  8. Advanced Stirling Radioisotope Generator: Design Processes, Reliability Analyses Impacts, and Extended Operation Tests

    NASA Astrophysics Data System (ADS)

    Ha, Chuong T.; Fernandez, René; Cornford, Steven L.; Feather, Martin S.

    2008-01-01

    NASA is currently funding an effort involving the Department of Energy (DOE), Lockheed Martin (LM), Glenn Research Center (GRC), and Sunpower (SP), Inc. to develop a high specific power Advanced Stirling Radioisotope Generator (ASRG). GRC and SP are responsible for providing the Stirling convertor, while LM is responsible for the generator housing, controller, and system integration. GRC also provides supporting technologies for various components as well as extended operation testing, both in air and in a thermal vacuum environment. Because of the 17-year life requirement of the ASRG, reliability considerations are the main design driver. Components such as the heater head, fasteners, magnets, and planar spring have been studied to ensure high reliability. To encompass unique design features, long lifetimes and extreme environmental conditions, both reliability analyses and qualification tests are used to support the design process. This paper presents an overview of the ASRG reliability approach and the impact of the Reliability Working Group (RWG) on the recently finished design effort. It also provides a summary of current and planned extended operation tests, specifically targeted to demonstrate long-life capability and to support further reliability assessment. In the event of no, or minimal failures during these extended tests, a Weibayes approach will be used to create a trend of improving reliability predictions.

  9. Reliability and Validity Evidence for Achievement Goal Models in High School Physical Education Settings

    ERIC Educational Resources Information Center

    Guan, Jianmin; McBride, Ron; Xiang, Ping

    2007-01-01

    Although empirical research in academic areas provides support for both a 3-factor as well as a 4-factor achievement goal model, both models were proposed and tested with a collegiate sample. Little is known about the generalizability of either model with high school level samples. This study was designed to examine whether the 3-factor model…

  10. Operational Impacts of Operating Reserve Demand Curves on Production Cost and Reliability

    SciTech Connect

    Krad, Ibrahim; Ibanez, Eduardo; Ela, Erik; Gao, Wenzhong

    2015-11-02

    The electric power industry landscape is continually evolving. As emerging technologies such as wind, solar, electric vehicles, and energy storage systems become more cost-effective and present in the system, traditional power system operating strategies will need to be reevaluated. The presence of wind and solar generation (commonly referred to as variable generation) may result in an increase in the variability and uncertainty of the net load profile. One mechanism to mitigate this is to schedule and dispatch additional operating reserves. These operating reserves aim to ensure that there is enough capacity online in the system to account for the increased variability and uncertainty occurring at finer temporal resolutions. A new operating reserve strategy, referred to as flexibility reserve, has been introduced in some regions. A similar implementation is explored in this paper, and its implications on power system operations are analyzed.

  11. Operational Impacts of Operating Reserve Demand Curves on Production Cost and Reliability: Preprint

    SciTech Connect

    Krad, Ibrahim; Ibanez, Eduardo; Ela, Erik; Gao, Wenzhong

    2015-10-27

    The electric power industry landscape is continually evolving. As emerging technologies such as wind, solar, electric vehicles, and energy storage systems become more cost-effective and present in the system, traditional power system operating strategies will need to be reevaluated. The presence of wind and solar generation (commonly referred to as variable generation) may result in an increase in the variability and uncertainty of the net load profile. One mechanism to mitigate this is to schedule and dispatch additional operating reserves. These operating reserves aim to ensure that there is enough capacity online in the system to account for the increased variability and uncertainty occurring at finer temporal resolutions. A new operating reserve strategy, referred to as flexibility reserve, has been introduced in some regions. A similar implementation is explored in this paper, and its implications on power system operations are analyzed.

  12. Piagetian Formal Operational Tasks: A Crossover Study of Learning Effect and Reliability

    ERIC Educational Resources Information Center

    Lawson, Anton E.; And Others

    1974-01-01

    The general purposes of this study were to analyze responses on five Piagetian formal operational tasks in a test-retest situation to determine the extent to which taking a pretest effected scores on posttests and to determine task and examiner reliabilities. Significant test score gains on Piagetian tasks appeared to result from test-retest…

  13. 29 CFR 779.219 - Unified operation may be achieved without common control or common ownership.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 29 Labor 3 2010-07-01 2010-07-01 false Unified operation may be achieved without common control or common ownership. 779.219 Section 779.219 Labor Regulations Relating to Labor (Continued) WAGE AND HOUR... Act May Apply; Enterprise Coverage Unified Operation Or Common Control § 779.219 Unified operation...

  14. Wind turbine reliability : understanding and minimizing wind turbine operation and maintenance costs.

    SciTech Connect

    Not Available

    2004-11-01

    Wind turbine system reliability is a critical factor in the success of a wind energy project. Poor reliability directly affects both the project's revenue stream through increased operation and maintenance (O&M) costs and reduced availability to generate power due to turbine downtime. Indirectly, the acceptance of wind-generated power by the financial and developer communities as a viable enterprise is influenced by the risk associated with the capital equipment reliability; increased risk, or at least the perception of increased risk, is generally accompanied by increased financing fees or interest rates. Cost of energy (COE) is a key project evaluation metric, both in commercial applications and in the U.S. federal wind energy program. To reflect this commercial reality, the wind energy research community has adopted COE as a decision-making and technology evaluation metric. The COE metric accounts for the effects of reliability through levelized replacement cost and unscheduled maintenance cost parameters. However, unlike the other cost contributors, such as initial capital investment and scheduled maintenance and operating expenses, costs associated with component failures are necessarily speculative. They are based on assumptions about the reliability of components that in many cases have not been operated for a complete life cycle. Due to the logistical and practical difficulty of replacing major components in a wind turbine, unanticipated failures (especially serial failures) can have a large impact on the economics of a project. The uncertainty associated with long-term component reliability has direct bearing on the confidence level associated with COE projections. In addition, wind turbine technology is evolving. New materials and designs are being incorporated in contemporary wind turbines with the ultimate goal of reducing weight, controlling loads, and improving energy capture. While the goal of these innovations is reduction in the COE, there is a

  15. Reliable operation of 976nm high power DFB broad area diode lasers with over 60% power conversion efficiency

    NASA Astrophysics Data System (ADS)

    Crump, P.; Schultz, C. M.; Wenzel, H.; Knigge, S.; Brox, O.; Maaßdorf, A.; Bugge, F.; Erbert, G.

    2011-02-01

    Diode lasers that deliver high continuous wave optical output powers (> 5W) within a narrow, temperature-stable spectral window are required for many applications. One technical solution is to bury Bragg-gratings within the semiconductor itself, using epitaxial overgrowth techniques to form distributed-feedback broad-area (DFB-BA) lasers. However, such stabilization is only of interest when reliability, operating power and power conversion efficiency are not compromised. Results will be presented from the ongoing optimization of such DFB-BA lasers at the Ferdinand-Braun- Institut (FBH). Our development work focused on 976nm devices with 90μm stripe width, as required for pumping Nd:YAG, as well as for direct applications. Such devices operate with a narrow spectral width of < 1nm (95% power content) to over 10W continuous wave (CW) optical output. Further optimization of epitaxial growth and device design has now largely eliminated the excess optical loss and electrical resistance typically associated with the overgrown grating layer. These developments have enabled, for the first time, DFB-BA lasers with peak CW power conversion efficiency of > 60% with < 1nm spectral width (95% power content). Reliable operation has also been demonstrated, with 90μm stripe devices operating for over 4000 hours to date without failure at 7W (CW). We detail the technological developments required to achieve these results and discuss the options for further improvements.

  16. Long term reliability and machine operation diagnosis with fiber optic sensors at large turbine generators

    NASA Astrophysics Data System (ADS)

    Bosselmann, T.; Strack, S.; Villnow, M.; Weidner, J. R.; Willsch, M.

    2013-05-01

    The increasing quantity of renewable energy in electric power generation leads to a higher flexibility in the operation of conventional power plants. The turbo generator has to face the influence of frequent start-stop-operation on thermal movement and vibration of the stator end windings. Large indirect cooled turbo generators have been equipped with FBG strain and temperature sensors to monitor the influence of peak load operation. Fiber optic accelerometers measure the vibration of the end windings at several turbine generators since many years of operation. The long term reliability of fiber optic vibration, temperature and strain sensors has been successfully proved during years of online operation. The analysis of these data in correlation to significant operation parameter lead to important diagnostic information.

  17. Achieving Lights-Out Operation of SMAP Using Ground Data System Automation

    NASA Technical Reports Server (NTRS)

    Sanders, Antonio

    2013-01-01

    The approach used in the SMAP ground data system to provide reliable, automated capabilities to conduct unattended operations has been presented. The impacts of automation on the ground data system architecture were discussed, including the three major automation patterns identified for SMAP and how these patterns address the operations use cases. The architecture and approaches used by SMAP will set the baseline for future JPL Earth Science missions.

  18. Operating Experience and Reliability Improvements on the 5 kW CW Klystron at Jefferson Lab

    NASA Astrophysics Data System (ADS)

    Nelson, R.; Holben, S.

    1997-05-01

    With substantial operating hours on the RF system, considerable information on reliability of the 5 kW CW klystrons has been obtained. High early failure rates led to examination of the operating conditions and failure modes. Internal ceramic contamination caused premature failure of gun potting material and ultimate tube demise through arcing or ceramic fracture. A planned course of repotting and reconditioning of approximately 300 klystrons, plus careful attention to operating conditions and periodic analysis of operational data, has substantially reduced the failure rate. It is anticipated that implementation of planned supplemental monitoring systems for the klystrons will allow most catastrophic failures to be avoided. By predicting end of life, tubes can be changed out before they fail, thus minimizing unplanned downtime. Initial tests have also been conducted on this same klystron operated at higher voltages with resultant higher output power. The outcome of these tests will provide information to be considered for future upgrades to the accelerator.

  19. Operating experience and reliability improvements on the 5 kW CW klystron at Jefferson Lab

    SciTech Connect

    Nelson, R.; Holben, S.

    1997-06-01

    With substantial operating hours on the RF system, considerable information on reliability of the 5 kW CW klystrons has been obtained. High early failure rates led to examination of the operating conditions and failure modes. Internal ceramic contamination caused premature failure of gun potting material and ultimate tube demise through arcing or ceramic fracture. A planned course of reporting and reconditioning of approximately 300 klystrons, plus careful attention to operating conditions and periodic analysis of operational data, has substantially reduced the failure rate. It is anticipated that implementation of planned supplemental monitoring systems for the klystrons will allow most catastrophic failures to be avoided. By predicting end of life, tubes can be changed out before they fail, thus minimizing unplanned downtime. Initial tests have also been conducted on this same klystron operated at higher voltages with resultant higher output power. The outcome of these tests will provide information to be considered for future upgrades to the accelerator.

  20. Knowledge Visualizations: A Tool to Achieve Optimized Operational Decision Making and Data Integration

    DTIC Science & Technology

    2015-06-01

    and pedigree possess additive implications toward the quality of the data utilized within the DSS. F. SUMMARY Decision - making theories such as...VISUALIZATIONS: A TOOL TO ACHIEVE OPTIMIZED OPERATIONAL DECISION MAKING AND DATA INTEGRATION by Paul C. Hudson Jeffrey A. Rzasa June 2015 Thesis...TOOL TO ACHIEVE OPTIMIZED OPERATIONAL DECISION MAKING AND DATA INTEGRATION 5. FUNDING NUMBERS 6. AUTHOR(S) Paul C. Hudson, and Jeffrey A. Rzasa

  1. Uncertainty quantification and reliability assessment in operational oil spill forecast modeling system.

    PubMed

    Hou, Xianlong; Hodges, Ben R; Feng, Dongyu; Liu, Qixiao

    2017-03-15

    As oil transport increasing in the Texas bays, greater risks of ship collisions will become a challenge, yielding oil spill accidents as a consequence. To minimize the ecological damage and optimize rapid response, emergency managers need to be informed with how fast and where oil will spread as soon as possible after a spill. The state-of-the-art operational oil spill forecast modeling system improves the oil spill response into a new stage. However uncertainty due to predicted data inputs often elicits compromise on the reliability of the forecast result, leading to misdirection in contingency planning. Thus understanding the forecast uncertainty and reliability become significant. In this paper, Monte Carlo simulation is implemented to provide parameters to generate forecast probability maps. The oil spill forecast uncertainty is thus quantified by comparing the forecast probability map and the associated hindcast simulation. A HyosPy-based simple statistic model is developed to assess the reliability of an oil spill forecast in term of belief degree. The technologies developed in this study create a prototype for uncertainty and reliability analysis in numerical oil spill forecast modeling system, providing emergency managers to improve the capability of real time operational oil spill response and impact assessment.

  2. Wind turbine reliability :understanding and minimizing wind turbine operation and maintenance costs.

    SciTech Connect

    Walford, Christopher A. (Global Energy Concepts. Kirkland, WA)

    2006-03-01

    Wind turbine system reliability is a critical factor in the success of a wind energy project. Poor reliability directly affects both the project's revenue stream through increased operation and maintenance (O&M) costs and reduced availability to generate power due to turbine downtime. Indirectly, the acceptance of wind-generated power by the financial and developer communities as a viable enterprise is influenced by the risk associated with the capital equipment reliability; increased risk, or at least the perception of increased risk, is generally accompanied by increased financing fees or interest rates. This paper outlines the issues relevant to wind turbine reliability for wind turbine power generation projects. The first sections describe the current state of the industry, identify the cost elements associated with wind farm O&M and availability and discuss the causes of uncertainty in estimating wind turbine component reliability. The latter sections discuss the means for reducing O&M costs and propose O&M related research and development efforts that could be pursued by the wind energy research community to reduce cost of energy.

  3. The Effect of Instructional Mode on School Achievement of Concrete and Formal Operational Students.

    ERIC Educational Resources Information Center

    Rastovac, John J.

    The effectiveness of audiotutorial and teacher-directed inquiry in promoting school achievement was explored. High school biology students from two dissimilar populations were administered ten Piagetian-styled tasks to determine the student's operational level. Analysis of data on operational level and age determined that inner-city students…

  4. A survey of HVDC operating and maintenance practices and their impact on reliability and performance

    SciTech Connect

    Cochrane, J.J.; Emerson, M.P.; Donahue, J.A.; Wolf, G.

    1996-01-01

    A questionnaire about operating, maintenance, and spare parts practices and station performance was sent to all HVDC converter stations worldwide. This survey is sponsored by IEEE Working Groups 15.05.08, Economics and Operating Strategies, and I7, Reliability of HVDC Converter Stations. Responses from 38 stations are analyzed, and information bout the most popular practices is reported. One important conclusion is that energy contracts, ac system constraints, and dedicated generation frequency have strong influences on the operation and maintenance practices of HVDC stations. A search is made for correlations between the operating, maintenance, and spare parts practices, including spending, and the stations` performance and availability. No conclusions about the most cost-effective practices can be made. The results are compared with those of a study published in 1992 which covered a few of the same topics.

  5. Improving Reliability of Service Operation Using FMEA Review and New Opportunity for Investigations

    NASA Astrophysics Data System (ADS)

    Sutrisno, Agung; Gunawan, Indra

    2016-01-01

    Despite its growing contribution to the global economy, investigation on the application status of service FMEA study to support realization of reliable service operation is very limited in literature. Motivated by such situation, the paper presented an initial survey on the status and research gaps in developing and applying FMEA in service sectors. Systematic preliminary survey using specific criteria are undertaken. Our study indicated that development and application of service FMEA are partially addressing the characteristics of service operations and it is still applied into the good deed and profit oriented operations. Opportunities for further investigation pertaining to advancement of its decision supporting tool for service risk appraisal, its modification to cope with sustainability related requirements and application of service FMEA in not for profit oriented operations are presented as new avenues for further investigation

  6. Operations & Maintenance Best Practices - A Guide to Achieving Operational Efficiency Release 3.0

    SciTech Connect

    2010-08-01

    This Operations and Maintenance (O&M) Best Practices Guide was developed under the direction of the U.S. Department of Energy’s Federal Energy Management Program (FEMP). The mission of FEMP is to facilitate the Federal Government’s implementation of sound, cost effective energy management and investment practices to enhance the nation’s energy security and environmental stewardship.

  7. Reliable and Fault-Tolerant Software-Defined Network Operations Scheme for Remote 3D Printing

    NASA Astrophysics Data System (ADS)

    Kim, Dongkyun; Gil, Joon-Min

    2015-03-01

    The recent wide expansion of applicable three-dimensional (3D) printing and software-defined networking (SDN) technologies has led to a great deal of attention being focused on efficient remote control of manufacturing processes. SDN is a renowned paradigm for network softwarization, which has helped facilitate remote manufacturing in association with high network performance, since SDN is designed to control network paths and traffic flows, guaranteeing improved quality of services by obtaining network requests from end-applications on demand through the separated SDN controller or control plane. However, current SDN approaches are generally focused on the controls and automation of the networks, which indicates that there is a lack of management plane development designed for a reliable and fault-tolerant SDN environment. Therefore, in addition to the inherent advantage of SDN, this paper proposes a new software-defined network operations center (SD-NOC) architecture to strengthen the reliability and fault-tolerance of SDN in terms of network operations and management in particular. The cooperation and orchestration between SDN and SD-NOC are also introduced for the SDN failover processes based on four principal SDN breakdown scenarios derived from the failures of the controller, SDN nodes, and connected links. The abovementioned SDN troubles significantly reduce the network reachability to remote devices (e.g., 3D printers, super high-definition cameras, etc.) and the reliability of relevant control processes. Our performance consideration and analysis results show that the proposed scheme can shrink operations and management overheads of SDN, which leads to the enhancement of responsiveness and reliability of SDN for remote 3D printing and control processes.

  8. Renewal of the Control System and Reliable Long Term Operation of the LHD Cryogenic System

    NASA Astrophysics Data System (ADS)

    Mito, T.; Iwamoto, A.; Oba, K.; Takami, S.; Moriuchi, S.; Imagawa, S.; Takahata, K.; Yamada, S.; Yanagi, N.; Hamaguchi, S.; Kishida, F.; Nakashima, T.

    The Large Helical Device (LHD) is a heliotron-type fusion plasma experimental machine which consists of a fully superconducting magnet system cooled by a helium refrigerator having a total equivalent cooling capacity of 9.2 kW@4.4 K. Seventeenplasma experimental campaigns have been performed successfully since1997 with high reliability of 99%. However, sixteen years have passed from the beginning of the system operation. Improvements are being implementedto prevent serious failures and to pursue further reliability.The LHD cryogenic control system was designed and developed as an open system utilizing latest control equipment of VME controllers and UNIX workstations at the construction time. Howeverthe generation change of control equipment has been advanced. Down-sizing of control deviceshas beenplanned from VME controllers to compact PCI controllers in order to simplify the system configuration and to improve the system reliability. The new system is composed of compact PCI controller and remote I/O connected with EtherNet/IP. Making the system redundant becomes possible by doubling CPU, LAN, and remote I/O respectively. The smooth renewal of the LHD cryogenic controlsystem and the further improvement of the cryogenic system reliability are reported.

  9. Operations & Maintenance Best Practices - A Guide to Achieving Operational Efficiency (Release 3)

    SciTech Connect

    Sullivan, Greg; Pugh, Ray; Melendez, Aldo P.; Hunt, W. D.

    2010-08-04

    This guide highlights operations and maintenance programs targeting energy and water efficiency that are estimated to save 5% to 20% on energy bills without a significant capital investment. The purpose of this guide is to provide you, the Operations and Maintenance (O&M)/Energy manager and practitioner, with useful information about O&M management, technologies, energy and water efficiency, and cost-reduction approaches. To make this guide useful and to reflect your needs and concerns, the authors met with O&M and Energy managers via Federal Energy Management Program (FEMP) workshops. In addition, the authors conducted extensive literature searches and contacted numerous vendors and industry experts. The information and case studies that appear in this guide resulted from these activities. It needs to be stated at the outset that this guide is designed to provide information on effective O&M as it applies to systems and equipment typically found at Federal facilities. This guide is not designed to provide the reader with step-by-step procedures for performing O&M on any specific piece of equipment. Rather, this guide first directs the user to the manufacturer's specifications and recommendations. In no way should the recommendations in this guide be used in place of manufacturer's recommendations. The recommendations in this guide are designed to supplement those of the manufacturer, or, as is all too often the case, provide guidance for systems and equipment for which all technical documentation has been lost. As a rule, this guide will first defer to the manufacturer's recommendations on equipment operation and maintenance.

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

    SciTech Connect

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

    2015-06-01

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

  11. The Effect of Stages and Levels of Automation and Reliability on Workload and Performance for Remotely Piloted Aircraft Operations

    DTIC Science & Technology

    2015-03-26

    REMOTELY PILOTED AIRCRAFT OPERATIONS THESIS MARCH 2015 Stephen P. Katrein, 2d Lieutenant, USAF AFIT-ENV-MS-15-M-201 DEPARTMENT OF THE AIR...RELIABILITY ON WORKLOAD AND PERFORMANCE FOR REMOTELY PILOTED AIRCRAFT OPERATIONS THESIS Presented to the Faculty Department of Systems...STAGES AND LEVELS OF AUTOMATION AND RELIABILITY ON WORKLOAD AND PERFORMANCE FOR REMOTELY PILOTED AIRCRAFT OPERATIONS Stephen P. Katrein, BS

  12. Reliable assessment of laparoscopic performance in the operating room using videotape analysis.

    PubMed

    Chang, Lily; Hogle, Nancy J; Moore, Brianna B; Graham, Mark J; Sinanan, Mika N; Bailey, Robert; Fowler, Dennis L

    2007-06-01

    The Global Operative Assessment of Laparoscopic Skills (GOALS) is a valid assessment tool for objectively evaluating the technical performance of laparoscopic skills in surgery residents. We hypothesized that GOALS would reliably differentiate between an experienced (expert) and an inexperienced (novice) laparoscopic surgeon (construct validity) based on a blinded videotape review of a laparoscopic cholecystectomy procedure. Ten board-certified surgeons actively engaged in the practice and teaching of laparoscopy reviewed and evaluated the videotaped operative performance of one novice and one expert laparoscopic surgeon using GOALS. Each reviewer recorded a score for both the expert and the novice videotape reviews in each of the 5 domains in GOALS (depth perception, bimanual dexterity, efficiency, tissue handling, and overall competence). The scores for the expert and the novice were compared and statistically analyzed using single-factor analysis of variance (ANOVA). The expert scored significantly higher than the novice did in the domains of depth perception (p = .005), bimanual dexterity (p = .001), efficiency (p = .001), and overall competence ( p = .001). Interrater reliability for the reviewers of the novice tape was Cronbach alpha = .93 and the expert tape was Cronbach alpha = .87. There was no difference between the two for tissue handling. The Global Operative Assessment of Laparoscopic Skills is a valid, objective assessment tool for evaluating technical surgical performance when used to blindly evaluate an intraoperative videotape recording of a laparoscopic procedure.

  13. The Achievement of Therapeutic Objectives Scale: Interrater Reliability and Sensitivity to Change in Short-Term Dynamic Psychotherapy and Cognitive Therapy

    ERIC Educational Resources Information Center

    Valen, Jakob; Ryum, Truls; Svartberg, Martin; Stiles, Tore C.; McCullough, Leigh

    2011-01-01

    This study examined interrater reliability and sensitivity to change of the Achievement of Therapeutic Objectives Scale (ATOS; McCullough, Larsen, et al., 2003) in short-term dynamic psychotherapy (STDP) and cognitive therapy (CT). The ATOS is a process scale originally developed to assess patients' achievements of treatment objectives in STDP,…

  14. Investigation of the impact of main control room digitalization on operators cognitive reliability in nuclear power plants.

    PubMed

    Zhou, Yong; Mu, Haiying; Jiang, Jianjun; Zhang, Li

    2012-01-01

    Currently, there is a trend in nuclear power plants (NPPs) toward introducing digital and computer technologies into main control rooms (MCRs). Safe generation of electric power in NPPs requires reliable performance of cognitive tasks such as fault detection, diagnosis, and response planning. The digitalization of MCRs has dramatically changed the whole operating environment, and the ways operators interact with the plant systems. If the design and implementation of the digital technology is incompatible with operators' cognitive characteristics, it may have negative effects on operators' cognitive reliability. Firstly, on the basis of three essential prerequisites for successful cognitive tasks, a causal model is constructed to reveal the typical human performance issues arising from digitalization. The cognitive mechanisms which they impact cognitive reliability are analyzed in detail. Then, Bayesian inference is used to quantify and prioritize the influences of these factors. It suggests that interface management and unbalanced workload distribution have more significant impacts on operators' cognitive reliability.

  15. Turbine Reliability and Operability Optimization through the use of Direct Detection Lidar Final Technical Report

    SciTech Connect

    Johnson, David K; Lewis, Matthew J; Pavlich, Jane C; Wright, Alan D; Johnson, Kathryn E; Pace, Andrew M

    2013-02-01

    The goal of this Department of Energy (DOE) project is to increase wind turbine efficiency and reliability with the use of a Light Detection and Ranging (LIDAR) system. The LIDAR provides wind speed and direction data that can be used to help mitigate the fatigue stress on the turbine blades and internal components caused by wind gusts, sub-optimal pointing and reactionary speed or RPM changes. This effort will have a significant impact on the operation and maintenance costs of turbines across the industry. During the course of the project, Michigan Aerospace Corporation (MAC) modified and tested a prototype direct detection wind LIDAR instrument; the resulting LIDAR design considered all aspects of wind turbine LIDAR operation from mounting, assembly, and environmental operating conditions to laser safety. Additionally, in co-operation with our partners, the National Renewable Energy Lab and the Colorado School of Mines, progress was made in LIDAR performance modeling as well as LIDAR feed forward control system modeling and simulation. The results of this investigation showed that using LIDAR measurements to change between baseline and extreme event controllers in a switching architecture can reduce damage equivalent loads on blades and tower, and produce higher mean power output due to fewer overspeed events. This DOE project has led to continued venture capital investment and engagement with leading turbine OEMs, wind farm developers, and wind farm owner/operators.

  16. Post-event human decision errors: operator action tree/time reliability correlation

    SciTech Connect

    Hall, R E; Fragola, J; Wreathall, J

    1982-11-01

    This report documents an interim framework for the quantification of the probability of errors of decision on the part of nuclear power plant operators after the initiation of an accident. The framework can easily be incorporated into an event tree/fault tree analysis. The method presented consists of a structure called the operator action tree and a time reliability correlation which assumes the time available for making a decision to be the dominating factor in situations requiring cognitive human response. This limited approach decreases the magnitude and complexity of the decision modeling task. Specifically, in the past, some human performance models have attempted prediction by trying to emulate sequences of human actions, or by identifying and modeling the information processing approach applicable to the task. The model developed here is directed at describing the statistical performance of a representative group of hypothetical individuals responding to generalized situations.

  17. 20W continuous wave reliable operation of 980nm broad-area single emitter diode lasers with an aperture of 96μm

    NASA Astrophysics Data System (ADS)

    Crump, P.; Blume, G.; Paschke, K.; Staske, R.; Pietrzak, A.; Zeimer, U.; Einfeldt, S.; Ginolas, A.; Bugge, F.; Häusler, K.; Ressel, P.; Wenzel, H.; Erbert, G.

    2009-02-01

    High power broad area diode lasers provide the optical energy for all high performance solid state and fiber laser systems. The maximum achievable power density from such systems is limited at source by the performance of the diode lasers. A crucial metric is the reliable continuous wave optical output power from a single broad area laser diode, typically for stripe widths in the 90-100 μm range, which is especially important for users relying on fibered multi-mode pumps. We present the results of a study investigating the reliable power limits of such 980nm sources. We find that 96μm stripe single emitters lasers at 20°C operate under continuous wave power of 20W per emitter for over 4000 hours (to date) without failure, with 60μm stripe devices operating reliably at 10W per stripe. Maximum power testing under 10Hz, 200μs QCW drive conditions shows that 96μm stripes reach 30W and 60μm stripes 21W per emitter, significantly above the reliable operation point. Results are also presented on step-stress-studies, where the current is step-wise increased until failure is observed, in order to clarify the remaining reliability limits. Finally, we detail the barriers to increased peak power and discuss how these can be overcome.

  18. Utilizing clad piping to improve process plant piping integrity, reliability, and operations

    SciTech Connect

    Chakravarti, B.

    1996-07-01

    During the past four years carbon steel piping clad with type 304L (UNS S30403) stainless steel has been used to solve the flow accelerated corrosion (FAC) problem in nuclear power plants with exceptional success. The product is designed to allow ``like for like`` replacement of damaged carbon steel components where the carbon steel remains the pressure boundary and type 304L (UNS S30403) stainless steel the corrosion allowance. More than 3000 feet of piping and 500 fittings in sizes from 6 to 36-in. NPS have been installed in the extraction steam and other lines of these power plants to improve reliability, eliminate inspection program, reduce O and M costs and provide operational benefits. This concept of utilizing clad piping in solving various corrosion problems in industrial and process plants by conservatively selecting a high alloy material as cladding can provide similar, significant benefits in controlling corrosion problems, minimizing maintenance cost, improving operation and reliability to control performance and risks in a highly cost effective manner. This paper will present various material combinations and applications that appear ideally suited for use of the clad piping components in process plants.

  19. Virtualization of Legacy Instrumentation Control Computers for Improved Reliability, Operational Life, and Management.

    PubMed

    Katz, Jonathan E

    2017-01-01

    Laboratories tend to be amenable environments for long-term reliable operation of scientific measurement equipment. Indeed, it is not uncommon to find equipment 5, 10, or even 20+ years old still being routinely used in labs. Unfortunately, the Achilles heel for many of these devices is the control/data acquisition computer. Often these computers run older operating systems (e.g., Windows XP) and, while they might only use standard network, USB or serial ports, they require proprietary software to be installed. Even if the original installation disks can be found, it is a burdensome process to reinstall and is fraught with "gotchas" that can derail the process-lost license keys, incompatible hardware, forgotten configuration settings, etc. If you have running legacy instrumentation, the computer is the ticking time bomb waiting to put a halt to your operation.In this chapter, I describe how to virtualize your currently running control computer. This virtualized computer "image" is easy to maintain, easy to back up and easy to redeploy. I have used this multiple times in my own lab to greatly improve the robustness of my legacy devices.After completing the steps in this chapter, you will have your original control computer as well as a virtual instance of that computer with all the software installed ready to control your hardware should your original computer ever be decommissioned.

  20. Effect of system workload on operating system reliability - A study on IBM 3081

    NASA Technical Reports Server (NTRS)

    Iyer, R. K.; Rossetti, D. J.

    1985-01-01

    This paper presents an analysis of operating system failures on an IBM 3081 running VM/SP. Three broad categories of software failures are found: error handling, program control or logic, and hardware related; it is found that more than 25 percent of software failures occur in the hardware/software interface. Measurements show that results on software reliability cannot be considered representative unless the system workload is taken into account. The overall CPU execution rate, although measured to be close to 100 percent most of the time, is not found to correlate strongly with the occurrence of failures. Possible reasons for the observed workload failure dependency, based on detailed investigations of the failure data, are discussed.

  1. The National Aeronautics and Space Administration Nondestructive Evaluation Program for Safe and Reliable Operations

    NASA Technical Reports Server (NTRS)

    Generazio, Ed

    2005-01-01

    The National Aeronautics and Space Administration (NASA) Nondestructive Evaluation (NDE) Program is presented. As a result of the loss of seven astronauts and the Space Shuttle Columbia on February 1, 2003, NASA has undergone many changes in its organization. NDE is one of the key areas that are recognized by the Columbia Accident Investigation Board (CAIB) that needed to be strengthened by warranting NDE as a discipline with Independent Technical Authority (iTA). The current NASA NDE system and activities are presented including the latest developments in inspection technologies being applied to the Space Transportation System (STS). The unfolding trends and directions in NDE for the future are discussed as they apply to assuring safe and reliable operations.

  2. Design and operation of a low cost, reliable millimeter-wave interferometer

    SciTech Connect

    Porte, L.; Rettig, C.L.; Peebles, W.A.; Ngyuen, X.

    1999-01-01

    Knowledge of basic plasma parameters, such as line integrated density and turbulence spectra, is essential for physics understanding and plasma control. Integration of plasma diagnostic systems into a single port combined with diagnostic cost reduction is an important advance that can impact measurement availability on all fusion devices. This article presents preliminary data from a unique, low cost and reliable millimeter-wave interferometer that has been integrated to operate simultaneously with a collective Thomson scattering system. The interferometer uses only one commercially available frequency chirped source and only one detector. The DIII-D system design will be described together with preliminary design of a tangentially viewing system for the Pegasus spherical torus experiment. {copyright} {ital 1999 American Institute of Physics.}

  3. Data Assembly and Processing for Operational Oceanography: 10 Years of Achievements

    DTIC Science & Technology

    2009-07-20

    detailed map of the very high velocities of the East Australian Current was a group rowing across the Tasman Sea from New Zealand in late 2007. Figure 16...the eddy field of the Tasman Sea , as exemplified by Figure 17. The subsurface temperature field is used operationally by the Australian Fisheries...GHRSST for SST. An overview of other data centers (wind and fluxes, ocean colour, sea ice) will also be given. Major progresses have been achieved

  4. Field Operations Program Chevrolet S-10 (Lead-Acid) Accelerated Reliability Testing - Final Report

    SciTech Connect

    J. Francfort; J. Argueta; M. Wehrey; D. Karner; L. Tyree

    1999-07-01

    This report summarizes the Accelerated Reliability testing of five lead-acid battery-equipped Chevrolet S-10 electric vehicles by the US Department of Energy's Field Operations Program and the Program's testing partners, Electric Transportation Applications (ETA) and Southern California Edison (SCE). ETA and SCE operated the S-10s with the goal of placing 25,000 miles on each vehicle within 1 year, providing an accelerated life-cycle analysis. The testing was performed according to established and published test procedures. The S-10s' average ranges were highest during summer months; changes in ambient temperature from night to day and from season-to-season impacted range by as much as 10 miles. Drivers also noted that excessive use of power during acceleration also had a dramatic effect on vehicle range. The spirited performance of the S-10s created a great temptation to inexperienced electric vehicle drivers to ''have a good time'' and to fully utilize the S-10's acceleration capability. The price of injudicious use of power is greatly reduced range and a long-term reduction in battery life. The range using full-power accelerations followed by rapid deceleration in city driving has been 20 miles or less.

  5. REMOTES: reliable and modular telescope solution for seamless operation and monitoring of various observation facilities

    NASA Astrophysics Data System (ADS)

    Jakubec, M.; Skala, P.; Sedlacek, M.; Nekola, M.; Strobl, J.; Blazek, M.; Hudec, R.

    2012-09-01

    Astronomers often need to put several pieces of equipment together and have to deploy them at a particular location. This task could prove to be a really tough challenge, especially for distant observing facilities with intricate operating conditions, poor communication infrastructure and unreliable power source. To have this task even more complicated, they also expect secure and reliable operation in both attended and unattended mode, comfortable software with user-friendly interface and full supervision over the observation site at all times. During reconstruction of the D50 robotic telescope facility, we faced many of the issues mentioned above. To get rid of them, we based our solution on a flexible group of hardware modules controlling the equipment of the observation site, connected together by the Ethernet network and orchestrated by our management software. This approach is both affordable and powerful enough to fulfill all of the observation requirements at the same time. We quickly figured out that the outcome of this project could also be useful for other observation facilities, because they are probably facing the same issues we have solved during our project. In this contribution, we will point out the key features and benefits of the solution for observers. We will demonstrate how the solution works at our observing location. We will also discuss typical management and maintenance scenarios and how we have supported them in our solution. Finally, the overall architecture and technical aspects of the solution will be presented and particular design and technology decisions will be clarified.

  6. A reliable low-maintenance flashlamp-pumped Ti:sapphire laser operating at 120 PPS

    SciTech Connect

    Witte, K.H.

    1994-03-01

    Flashlamp-pumped Ti:sapphire lasers have been reported to produce high-energy pulses with broad tunability. However, with the flashlamps operated close to their explosion energy, and thermal loading effects in the laser rod, these lasers were restricted to low repetition rates (typically around 10 PPS). Higher repetition rates at constant laser pulse energy reduce the flashlamp lifetime drastically. The author reports on a reliable flashlamp-pumped Ti:sapphire laser that has been operating at 120 PPS for over 10{sup 9} shots with the only cavity or pump chamber maintenance being flashlamp changes less than every 2{times}10{sup 8} pulses -- the lowest maintenance reported. A specular dual-lamp pump chamber was used to pump a 4 mm {times} 6 inches, 0.1% doped Ti:sapphire rod. This resulted in a very low lasing threshold, which ensured a stable output at low pump levels. The criterion for pump power was to obtain a highly stable output at the edge of the selected tuning range, from 790 to 860 nm. The combination of flashlamp walls, flashlamp flow tubes, and rod solarization.

  7. Renewable Resource Integration Project - Scoping Study of Strategic Transmission, Operations, and Reliability Issues

    SciTech Connect

    Eto, Joseph; Budhraja, Vikram; Ballance, John; Dyer, Jim; Mobasheri, Fred; Eto, Joseph

    2008-07-01

    California is on a path to increase utilization of renewable resources. California will need to integrate approximately 30,000 megawatts (MW) of new renewable generation in the next 20 years. Renewable resources are typically located in remote locations, not near the load centers. Nearly two/thirds or 20,000 MW of new renewable resources needed are likely to be delivered to Los Angeles Basin transmission gateways. Integration of renewable resources requires interconnection to the power grid, expansion of the transmission system capability between the backbone power grid and transmission gateways, and increase in delivery capacity from transmission gateways to the local load centers. To scope the transmission, operations, and reliability issues for renewables integration, this research focused on the Los Angeles Basin Area transmission gateways where most of new renewables are likely. Necessary actions for successful renewables integration include: (1) Expand Los Angeles Basin Area transmission gateway and nomogram limits by 10,000 to 20,000 MW; (2) Upgrade local transmission network for deliverability to load centers; (3) Secure additional storage, demand management, automatic load control, dynamic pricing, and other resources that meet regulation and ramping needed in real time operations; (4) Enhance local voltage support; and (5) Expand deliverability from Los Angeles to San Diego and Northern California.

  8. Instrumentation and Control Needs for Reliable Operation of Lunar Base Surface Nuclear Power Systems

    NASA Technical Reports Server (NTRS)

    Turso, James; Chicatelli, Amy; Bajwa, Anupa

    2005-01-01

    needed to enable this critical functionality of autonomous operation. It will be imperative to consider instrumentation and control requirements in parallel to system configuration development so as to identify control-related, as well as integrated system-related, problem areas early to avoid potentially expensive work-arounds . This paper presents an overview of the enabling technologies necessary for the development of reliable, autonomous lunar base nuclear power systems with an emphasis on system architectures and off-the-shelf algorithms rather than hardware. Autonomy needs are presented in the context of a hypothetical lunar base nuclear power system. The scenarios and applications presented are hypothetical in nature, based on information from open-literature sources, and only intended to provoke thought and provide motivation for the use of autonomous, intelligent control and diagnostics.

  9. Reliability and Validity Evidence of Scores on the Achievement Goal Tendencies Questionnaire in a Sample of Spanish Students of Compulsory Secondary Education

    ERIC Educational Resources Information Center

    Ingles, Candido J.; Garcia-Fernandez, Jose M.; Castejon, Juan L.; Valle, Antonio; Delgado, Beatriz; Marzo, Juan C.

    2009-01-01

    This study examined the reliability and validity evidence drawn from the scores of the Spanish version of the Achievement Goal Tendencies Questionnaire (AGTQ) using a sample of 2,022 (51.1% boys) Spanish students from grades 7 to 10. Confirmatory factor analysis replicated the correlated three-factor structure of the AGTQ in this sample: Learning…

  10. Use of Frequency Response Metrics to Assess the Planning and Operating Requirements for Reliable Integration of Variable Renewable Generation

    SciTech Connect

    Eto, Joseph H.; Undrill, John; Mackin, Peter; Daschmans, Ron; Williams, Ben; Haney, Brian; Hunt, Randall; Ellis, Jeff; Illian, Howard; Martinez, Carlos; O'Malley, Mark; Coughlin, Katie; LaCommare, Kristina Hamachi

    2010-12-20

    An interconnected electric power system is a complex system that must be operated within a safe frequency range in order to reliably maintain the instantaneous balance between generation and load. This is accomplished by ensuring that adequate resources are available to respond to expected and unexpected imbalances and restoring frequency to its scheduled value in order to ensure uninterrupted electric service to customers. Electrical systems must be flexible enough to reliably operate under a variety of"change" scenarios. System planners and operators must understand how other parts of the system change in response to the initial change, and need tools to manage such changes to ensure reliable operation within the scheduled frequency range. This report presents a systematic approach to identifying metrics that are useful for operating and planning a reliable system with increased amounts of variable renewable generation which builds on existing industry practices for frequency control after unexpected loss of a large amount of generation. The report introduces a set of metrics or tools for measuring the adequacy of frequency response within an interconnection. Based on the concept of the frequency nadir, these metrics take advantage of new information gathering and processing capabilities that system operators are developing for wide-area situational awareness. Primary frequency response is the leading metric that will be used by this report to assess the adequacy of primary frequency control reserves necessary to ensure reliable operation. It measures what is needed to arrest frequency decline (i.e., to establish frequency nadir) at a frequency higher than the highest set point for under-frequency load shedding within an interconnection. These metrics can be used to guide the reliable operation of an interconnection under changing circumstances.

  11. Charging performance of automotive batteries-An underestimated factor influencing lifetime and reliable battery operation

    NASA Astrophysics Data System (ADS)

    Sauer, Dirk Uwe; Karden, Eckhard; Fricke, Birger; Blanke, Holger; Thele, Marc; Bohlen, Oliver; Schiffer, Julia; Gerschler, Jochen Bernhard; Kaiser, Rudi

    Dynamic charge acceptance and charge acceptance under constant voltage charging conditions are for two reasons essential for lead-acid battery operation: energy efficiency in applications with limited charging time (e.g. PV systems or regenerative braking in vehicles) and avoidance of accelerated ageing due to sulphation. Laboratory tests often use charge regimes which are beneficial for the battery life, but which differ significantly from the operating conditions in the field. Lead-acid batteries in applications with limited charging time and partial-state-of-charge operation are rarely fully charged due to their limited charge acceptance. Therefore, they suffer from sulphation and early capacity loss. However, when appropriate charging strategies are applied most of the lost capacity and thus performance for the user may be recovered. The paper presents several aspects of charging regimes and charge acceptance. Theoretical and experimental investigations show that temperature is the most critical parameter. Full charging within short times can be achieved only at elevated temperatures. A strong dependency of the charge acceptance during charging pulses on the pre-treatment of the battery can be observed, which is not yet fully understood. But these effects have a significant impact on the fuel efficiency of micro-hybrid electric vehicles.

  12. Design considerations in achieving 1 MW CW operation with a whispering-gallery-mode gyrotron

    SciTech Connect

    Felch, K.; Feinstein, J.; Hess, C.; Huey, H.; Jongewaard, E.; Jory, H.; Neilson, J.; Pendleton, R.; Pirkle, D.; Zitelli, L. )

    1989-09-01

    Varian is developing high-power, CW gyrotrons at frequencies in the range 100 GHz to 150 GHz, for use in electron cyclotron heating applications. Early test vehicles have utilized a TE{sub 15,2,1} interaction cavity, have achieved short-pulse power levels of 820 kW and average power levels of 80 kW at 140 GHz. Present tests are aimed at reaching 400 kW under CW operating conditions and up to 1 MW for short pulse durations. Work is also underway on modifications to the present design that will enable power levels of up to 1 MW CW to be achieved. 7 refs., 2 figs.

  13. Complementary split ring resonator metamaterial to achieve multifrequency operation in microstrip-based radiating structure design

    NASA Astrophysics Data System (ADS)

    Patel, Shobhit K.; Kosta, Yogeshwar

    2014-02-01

    Following recent findings on metamaterials, a miniaturized microstrip patch antenna loaded with a complementary split ring resonator (CSRR) was investigated for multiband operation. The proposed structure has a CSRR loaded in the base of the antenna to improve its performance and to make it a metamaterial. Metamaterials exhibit qualitatively new electromagnetic response functions that cannot be found in nature. The CSRR-loaded base allows simultaneous operation over several frequencies. Here, a total of seven bands were achieved by loading the patch antenna with the CSRR. The seven bands were centered around frequencies of 4.33 GHz, 5.29 GHz, 6.256 GHz, 7.066 GHz, 7.846 GHz, 8.86 GHz, and 9.75 GHz. Design results were obtained by using a high-frequency structure simulator that is used for simulating microwave passive components.

  14. A new topology of fuel cell hybrid power source for efficient operation and high reliability

    NASA Astrophysics Data System (ADS)

    Bizon, Nicu

    2011-03-01

    This paper analyzes a new fuel cell Hybrid Power Source (HPS) topology having the feature to mitigate the current ripple of the fuel cell inverter system. In the operation of the inverter system that is grid connected or supplies AC motors in vehicle application, the current ripple normally appears at the DC port of the fuel cell HPS. Consequently, if mitigation measures are not applied, this ripple is back propagated to the fuel cell stack. Other features of the proposed fuel cell HPS are the Maximum Power Point (MPP) tracking, high reliability in operation under sharp power pulses and improved energy efficiency in high power applications. This topology uses an inverter system directly powered from the appropriate fuel cell stack and a controlled buck current source as low power source used for ripple mitigation. The low frequency ripple mitigation is based on active control. The anti-ripple current is injected in HPS output node and this has the LF power spectrum almost the same with the inverter ripple. Consequently, the fuel cell current ripple is mitigated by the designed active control. The ripple mitigation performances are evaluated by indicators that are defined to measure the mitigation ratio of the low frequency harmonics. In this paper it is shown that good performances are obtained by using the hysteretic current control, but better if a dedicated nonlinear controller is used. Two ways to design the nonlinear control law are proposed. First is based on simulation trials that help to draw the characteristic of ripple mitigation ratio vs. fuel cell current ripple. The second is based on Fuzzy Logic Controller (FLC). The ripple factor is up to 1% in both cases.

  15. UAV Research at NASA Langley: Towards Safe, Reliable, and Autonomous Operations

    NASA Technical Reports Server (NTRS)

    Davila, Carlos G.

    2016-01-01

    Unmanned Aerial Vehicles (UAV) are fundamental components in several aspects of research at NASA Langley, such as flight dynamics, mission-driven airframe design, airspace integration demonstrations, atmospheric science projects, and more. In particular, NASA Langley Research Center (Langley) is using UAVs to develop and demonstrate innovative capabilities that meet the autonomy and robotics challenges that are anticipated in science, space exploration, and aeronautics. These capabilities will enable new NASA missions such as asteroid rendezvous and retrieval (ARRM), Mars exploration, in-situ resource utilization (ISRU), pollution measurements in historically inaccessible areas, and the integration of UAVs into our everyday lives all missions of increasing complexity, distance, pace, and/or accessibility. Building on decades of NASA experience and success in the design, fabrication, and integration of robust and reliable automated systems for space and aeronautics, Langley Autonomy Incubator seeks to bridge the gap between automation and autonomy by enabling safe autonomous operations via onboard sensing and perception systems in both data-rich and data-deprived environments. The Autonomy Incubator is focused on the challenge of mobility and manipulation in dynamic and unstructured environments by integrating technologies such as computer vision, visual odometry, real-time mapping, path planning, object detection and avoidance, object classification, adaptive control, sensor fusion, machine learning, and natural human-machine teaming. These technologies are implemented in an architectural framework developed in-house for easy integration and interoperability of cutting-edge hardware and software.

  16. Reliable operation of the Brookhaven EBIS for highly charged ion production for RHIC and NSRL

    SciTech Connect

    Beebe, E. Alessi, J. Binello, S. Kanesue, T. McCafferty, D. Morris, J. Okamura, M. Pikin, A. Ritter, J. Schoepfer, R.

    2015-01-09

    An Electron Beam Ion Source for the Relativistic Heavy Ion Collider (RHIC EBIS) was commissioned at Brookhaven in September 2010 and since then it routinely supplies ions for RHIC and NASA Space Radiation Laboratory (NSRL) as the main source of highly charged ions from Helium to Uranium. Using three external primary ion sources for 1+ injection into the EBIS and an electrostatic injection beam line, ion species at the EBIS exit can be switched in 0.2 s. A total of 16 different ion species have been produced to date. The length and the capacity of the ion trap have been increased by 20% by extending the trap by two more drift tubes, compared with the original design. The fraction of Au{sup 32+} in the EBIS Au spectrum is approximately 12% for 70-80% electron beam neutralization and 8 pulses operation in a 5 Hertz train and 4-5 s super cycle. For single pulse per super cycle operation and 25% electron beam neutralization, the EBIS achieves the theoretical Au{sup 32+} fractional output of 18%. Long term stability has been very good with availability of the beam from RHIC EBIS during 2012 and 2014 RHIC runs approximately 99.8%.

  17. Reliable operation of the Brookhaven EBIS for highly charged ion production for RHIC and NSRL

    NASA Astrophysics Data System (ADS)

    Beebe, E.; Alessi, J.; Binello, S.; Kanesue, T.; McCafferty, D.; Morris, J.; Okamura, M.; Pikin, A.; Ritter, J.; Schoepfer, R.

    2015-01-01

    An Electron Beam Ion Source for the Relativistic Heavy Ion Collider (RHIC EBIS) was commissioned at Brookhaven in September 2010 and since then it routinely supplies ions for RHIC and NASA Space Radiation Laboratory (NSRL) as the main source of highly charged ions from Helium to Uranium. Using three external primary ion sources for 1+ injection into the EBIS and an electrostatic injection beam line, ion species at the EBIS exit can be switched in 0.2 s. A total of 16 different ion species have been produced to date. The length and the capacity of the ion trap have been increased by 20% by extending the trap by two more drift tubes, compared with the original design. The fraction of Au32+ in the EBIS Au spectrum is approximately 12% for 70-80% electron beam neutralization and 8 pulses operation in a 5 Hertz train and 4-5 s super cycle. For single pulse per super cycle operation and 25% electron beam neutralization, the EBIS achieves the theoretical Au32+ fractional output of 18%. Long term stability has been very good with availability of the beam from RHIC EBIS during 2012 and 2014 RHIC runs approximately 99.8%.

  18. A Study of General Cognitive Operations in Two Achievement Test Batteries and Their Relationship to Item Difficulty.

    ERIC Educational Resources Information Center

    Marzano, Robert J.; Jesse, Daniel M.

    In this study 6,942 items from two standardized achievement test batteries--the Stanford (Early School Achievement Battery, Achievement Battery, and Test of Academic Skills) and the Comprehensive Test of Basic Skills--were analyzed. Focus was on determining: (1) the extent to which these test batteries included general cognitive operations (GCOs)…

  19. Using operational data to estimate the reliable yields of water-supply wells

    NASA Astrophysics Data System (ADS)

    Misstear, Bruce D. R.; Beeson, Sarah

    The reliable yield of a water-supply well depends on many different factors, including the properties of the well and the aquifer; the capacities of the pumps, raw-water mains, and treatment works; the interference effects from other wells; and the constraints imposed by ion licences, water quality, and environmental issues. A relatively simple methodology for estimating reliable yields has been developed that takes into account all of these factors. The methodology is based mainly on an analysis of water-level and source-output data, where such data are available. Good operational data are especially important when dealing with wells in shallow, unconfined, fissure-flow aquifers, where actual well performance may vary considerably from that predicted using a more analytical approach. Key issues in the yield-assessment process are the identification of a deepest advisable pumping water level, and the collection of the appropriate well, aquifer, and operational data. Although developed for water-supply operators in the United Kingdom, this approach to estimating the reliable yields of water-supply wells using operational data should be applicable to a wide range of hydrogeological conditions elsewhere. Résumé La productivité d'un puits capté pour l'adduction d'eau potable dépend de différents facteurs, parmi lesquels les propriétés du puits et de l'aquifère, la puissance des pompes, le traitement des eaux brutes, les effets d'interférences avec d'autres puits et les contraintes imposées par les autorisations d'exploitation, par la qualité des eaux et par les conditions environnementales. Une méthodologie relativement simple d'estimation de la productivité qui prenne en compte tous ces facteurs a été mise au point. Cette méthodologie est basée surtout sur une analyse des données concernant le niveau piézométrique et le débit de prélèvement, quand ces données sont disponibles. De bonnes données opérationnelles sont particuli

  20. Guidelines for Assessing the Reliability and Validity of Tools, Techniques and Methods Used to Support Influence Operations

    DTIC Science & Technology

    2010-10-01

    Influence Ops TTMs development more closely with that of traditional Operational Analysis (OA) models . The key objectives are to ensure that Influence Ops...Operational Analysis modelling capabilities. All TTMs should be subject to R&V assessment by review. Those TTMs that produce specific analytical...This paper provides recommended guidance for assessing the reliability and validity (R&V) of the tools, techniques and methods ( TTMs ) developed to

  1. Connection Between Internal Structural Stresses of the Ist and the IInd kind and Operational Reliability of the Boiler Heating Surface

    NASA Astrophysics Data System (ADS)

    Lyubimova, Lyudmila; Tabakaev, Roman; Tashlykov, Alexander; Zavorin, Alexander; Zyubanov, Vadim

    2016-02-01

    This paper presents new approaches to solving problems of forecasting the life of heating surface of boilers, based on an analysis of internal structural stresses of the first and second kind that could affect the intragranular and intergranular strength and reliability of the pipeline in continuous operation by making it work without damage by preventing the disclosure of zone cracks.

  2. 75 FR 81157 - Version One Regional Reliability Standard for Transmission Operations

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-12-27

    ... requests additional information. The Commission also proposes to direct WECC to develop certain limited.... FOR FURTHER INFORMATION CONTACT: Mindi Sauter (Legal Information), Office of the General Counsel... Henery (Technical Information), Office of Electric Reliability, Division of Policy Analysis...

  3. Cryosat: ESA'S Ice Explorer Mission, 6 years in operations: status and achievements

    NASA Astrophysics Data System (ADS)

    Parrinello, Tommaso; Maestroni, Elia; Krassenburg, Mike; Badessi, Stefano; Bouffard, Jerome; Frommknecht, Bjorn; Davidson, Malcolm; Fornari, Marco; Scagliola, Michele

    2016-04-01

    CryoSat-2 was launched on the 8th April 2010 and it is the first European ice mission dedicated to monitoring precise changes in the thickness of polar ice sheets and floating sea ice over a 3-year period. CryoSat-2 carries an innovative radar altimeter called the Synthetic Aperture Interferometric Altimeter (SIRAL) with two antennas and with extended capabilities to meet the measurement requirements for ice-sheets elevation and sea-ice freeboard. Initial results have shown that data is of high quality thanks to an altimeter that is behaving exceptional well within its design specifications. The CryoSat mission reached its 6th years of operational life in April 2016. Since its launch has delivered high quality products to the worldwide cryospheric and marine community that is increasing every year. Scope of this paper is to describe the current mission status and its main scientific achievements. Topics will also include programmatic highlights and information on the next scientific development of the mission in its extended period of operations.

  4. Highly-reliable operation of 638-nm broad stripe laser diode with high wall-plug efficiency for display applications

    NASA Astrophysics Data System (ADS)

    Yagi, Tetsuya; Shimada, Naoyuki; Nishida, Takehiro; Mitsuyama, Hiroshi; Miyashita, Motoharu

    2013-03-01

    Laser based displays, as pico to cinema laser projectors have gathered much attention because of wide gamut, low power consumption, and so on. Laser light sources for the displays are operated mainly in CW, and heat management is one of the big issues. Therefore, highly efficient operation is necessitated. Also the light sources for the displays are requested to be highly reliable. 638 nm broad stripe laser diode (LD) was newly developed for high efficiency and highly reliable operation. An AlGaInP/GaAs red LD suffers from low wall plug efficiency (WPE) due to electron overflow from an active layer to a p-cladding layer. Large optical confinement factor (Γ) design with AlInP cladding layers is adopted to improve the WPE. The design has a disadvantage for reliable operation because the large Γ causes high optical density and brings a catastrophic optical degradation (COD) at a front facet. To overcome the disadvantage, a window-mirror structure is also adopted in the LD. The LD shows WPE of 35% at 25°C, highest record in the world, and highly stable operation at 35°C, 550 mW up to 8,000 hours without any catastrophic optical degradation.

  5. New insulating materials and their use to achieve high operating stresses in electrostatic machines

    NASA Astrophysics Data System (ADS)

    Cooke, Chathan M.

    1986-02-01

    Compressed gas insulation has provided the main insulation for sustaining terminal voltages of electrostatic accelerators. Essentially coaxial geometry is used with mechanical support of the terminal achieved by long columns which also support the acceleration tubes. Because of the vacuum insulation in the acceleration tubes, the electric gradient along the columns is typically 10-20 kV/cm, whereas the radial gas gap can operate at stresses about ten times larger. Until now, the terminal support has always been located in the low stress axial direction along the column and not in the radial high stress region. This paper is concerned with support insulation to be used in the radial direction. Advantages of radial supports include: simpler, more compact column structures, higher total voltages, and support of discrete stress redistribution electrodes such as vivitron. Important factors to the design of radial support insulators include the insulation constraints imposed by the gas gap, mechanical contact to the solid insulator, and basic limits of gas-solid dielectric interfaces. The gas gap insulation strength is shown to be limited by surface microirregularities and this accounts for electrode area and pressure effects. Based on the gas gap requirements, a design strategy for the insulators is developed. Epoxy is employed as the dielectric to allow the use of cast-in metal inserts at the ends. The inserts provide mechanical contact, shielding of the triple junction, and redistribution of the interface electric stresses. By careful design, the electric stress on the interface is made lower than that in the plain coaxial electrode gap. Practical experience shows that voltage increases linearly with insulator length and that designs achieve more than 10 MV/m into the multimegavolt region.

  6. Operational scale entomological intervention for malaria control: strategies, achievements and challenges in Zambia

    PubMed Central

    2013-01-01

    Background While consensus on malaria vector control policy and strategy has stimulated unprecedented political-will, backed by international funding organizations and donors, vector control interventions are expansively being implemented based on assumptions with unequaled successes. This manuscript reports on the strategies, achievements and challenges of the past and contemporary malaria vector control efforts in Zambia. Case description All available information and accessible archived documentary records on malaria vector control in Zambia were reviewed. Retrospective analysis of routine surveillance data from the Health Management Information System (HMIS), data from population-based household surveys and various operations research reports was conducted to assess the status in implementing policies and strategies. Discussion and evaluation Empirical evidence is critical for informing policy decisions and tailoring interventions to local settings. Thus, the World Health Organization (WHO) encourages the adoption of the integrated vector management (IVM) strategy which is a rational decision making process for optimal use of available resources. One of the key features of IVM is capacity building at the operational level to plan, implement, monitor and evaluate vector control and its epidemiological and entomological impact. In Zambia, great progress has been made in implementing WHO-recommended vector control policies and strategies within the context of the IVM Global Strategic framework with strong adherence to its five key attributes. Conclusions The country has solid, consistent and coordinated policies, strategies and guidelines for malaria vector control. The Zambian experience demonstrates the significance of a coordinated multi-pronged IVM approach effectively operationalized within the context of a national health system. PMID:23298401

  7. Emotional-volitional components of operator reliability. [sensorimotor function testing under stress

    NASA Technical Reports Server (NTRS)

    Mileryan, Y. A.

    1975-01-01

    Sensorimotor function testing in a tracking task under stressfull working conditions established a psychological characterization for a successful aviation pilot: Motivation significantly increased the reliability and effectiveness of their work. Their acitivities were aimed at suppressing weariness and the feeling of fear caused by the stress factors; they showed patience, endurance, persistence, and a capacity for lengthy volitional efforts.

  8. Towards an Operational Definition of Effective Co-Teaching: Instrument Development, Validity, and Reliability

    ERIC Educational Resources Information Center

    La Monte, Michelle Evonne

    2012-01-01

    This study focused on developing a valid and reliable instrument that can not only identify successful co-teaching, but also the professional development needs of co-teachers and their administrators in public schools. Two general questions about the quality of co-teaching were addressed in this study: (a) How well did descriptors within each of…

  9. A Quantitative Risk Analysis Framework for Evaluating and Monitoring Operational Reliability of Cloud Computing

    ERIC Educational Resources Information Center

    Islam, Muhammad Faysal

    2013-01-01

    Cloud computing offers the advantage of on-demand, reliable and cost efficient computing solutions without the capital investment and management resources to build and maintain in-house data centers and network infrastructures. Scalability of cloud solutions enable consumers to upgrade or downsize their services as needed. In a cloud environment,…

  10. Children's effortful control and academic achievement: do relational peer victimization and classroom participation operate as mediators?

    PubMed

    Valiente, Carlos; Swanson, Jodi; Lemery-Chalfant, Kathryn; Berger, Rebecca H

    2014-08-01

    Given that early academic achievement is related to numerous developmental outcomes, understanding processes that promote early success in school is important. This study was designed to clarify how students' (N=291; M age in fall of kindergarten=5.66 years, SD=0.39 year) effortful control, relational peer victimization, and classroom participation relate to achievement, as students progress from kindergarten to first grade. Effortful control and achievement were assessed in kindergarten, classroom participation and relational peer victimization were assessed in the fall of first grade, and achievement was reassessed in the spring of first grade. Classroom participation, but not relational peer victimization, mediated relations between effortful control and first grade standardized and teacher-rated achievement, controlling for kindergarten achievement. Findings suggest that aspects of classroom participation, such as the ability to work independently, may be useful targets of intervention for enhancing academic achievement in young children.

  11. Operational Vision: The Joint Force Commander’s Essential Quality to Achieve Success in the Future Operating Environment

    DTIC Science & Technology

    2013-05-20

    an understanding and ability to competently leverage to yield a favorable operational outcome. 12 In his monograph Vulcan Anvil, Professor James J...DC: CJCS, 11 August 2011), II-3. 13 James J. Schneider, Vulcan Anvil: The American Civil War and the Foundations of Operational Art, Theoretical

  12. The Role of Demand Resources In Regional Transmission Expansion Planning and Reliable Operations

    SciTech Connect

    Kirby, Brendan J

    2006-07-01

    Investigating the role of demand resources in regional transmission planning has provided mixed results. On one hand there are only a few projects where demand response has been used as an explicit alternative to transmission enhancement. On the other hand there is a fair amount of demand response in the form of energy efficiency, peak reduction, emergency load shedding, and (recently) demand providing ancillary services. All of this demand response reduces the need for transmission enhancements. Demand response capability is typically (but not always) factored into transmission planning as a reduction in the load which must be served. In that sense demand response is utilized as an alternative to transmission expansion. Much more demand response is used (involuntarily) as load shedding under extreme conditions to prevent cascading blackouts. The amount of additional transmission and generation that would be required to provide the current level of reliability if load shedding were not available is difficult to imagine and would be impractical to build. In a very real sense demand response solutions are equitably treated in every region - when proposed, demand response projects are evaluated against existing reliability and economic criteria. The regional councils, RTOs, and ISOs identify needs. Others propose transmission, generation, or responsive load based solutions. Few demand response projects get included in transmission enhancement plans because few are proposed. But this is only part of the story. Several factors are responsible for the current very low use of demand response as a transmission enhancement alternative. First, while the generation, transmission, and load business sectors each deal with essentially the same amount of electric power, generation and transmission companies are explicitly in the electric power business but electricity is not the primary business focus of most loads. This changes the institutional focus of each sector. Second

  13. Deep Space Network equipment performance, reliability, and operations management information system

    NASA Technical Reports Server (NTRS)

    Cooper, T.; Lin, J.; Chatillon, M.

    2002-01-01

    The Deep Space Mission System (DSMS) Operations Program Office and the DeepSpace Network (DSN) facilities utilize the Discrepancy Reporting Management System (DRMS) to collect, process, communicate and manage data discrepancies, equipment resets, physical equipment status, and to maintain an internal Station Log. A collaborative effort development between JPL and the Canberra Deep Space Communication Complex delivered a system to support DSN Operations.

  14. Improving Reliability of High Power Quasi-CW Laser Diode Arrays Operating in Long Pulse Mode

    NASA Technical Reports Server (NTRS)

    Amzajerdian, Farzin; Meadows, Byron L.; Barnes, Bruce W.; Lockard, George E.; Singh, Upendra N.; Kavaya, Michael J.; Baker, Nathaniel R.

    2006-01-01

    Operating high power laser diode arrays in long pulse regime of about 1 msec, which is required for pumping 2-micron thulium and holmium-based lasers, greatly limits their useful lifetime. This paper describes performance of laser diode arrays operating in long pulse mode and presents experimental data of the active region temperature and pulse-to-pulse thermal cycling that are the primary cause of their premature failure and rapid degradation. This paper will then offer a viable approach for determining the optimum design and operational parameters leading to the maximum attainable lifetime.

  15. RELIABILITY MODELS OF AGING PASSIVE COMPONENTS INFORMED BY MATERIALS DEGRADATION METRICS TO SUPPORT LONG-TERM REACTOR OPERATIONS

    SciTech Connect

    Unwin, Stephen D.; Lowry, Peter P.; Toyooka, Michael Y.

    2012-05-01

    Paper describes a methodology for the synthesis of nuclear power plant service data with expert-elicited materials degradation information to estimate the future failure rates of passive components. This method should be an important resource to long-term plant operations and reactor life extension. Conventional probabilistic risk assessments (PRAs) are not well suited to addressing long-term reactor operations. Since passive structures and components are among those for which replacement can be least practical, they might be expected to contribute increasingly to risk in an aging plant; yet, passives receive limited treatment in PRAs. Furthermore, PRAs produce only snapshots of risk based on the assumption of time-independent component failure rates. This assumption is unlikely to be valid in aging systems. The treatment of aging passive components in PRA presents challenges. Service data to quantify component reliability models are sparse, and this is exacerbated by the greater data demands of age-dependent reliability models. Another factor is that there can be numerous potential degradation mechanisms associated with the materials and operating environment of a given component. This deepens the data problem since risk-informed management of component aging will demand an understanding of the long-term risk significance of individual degradation mechanisms. In this paper we describe a Bayesian methodology that integrates metrics of materials degradation susceptibility with available plant service data to estimate age-dependent passive component reliabilities. Integration of these models into conventional PRA will provide a basis for materials degradation management informed by predicted long-term operational risk.

  16. Formal Operational Precocity and Achievement in Biology among Some Nigerian High School Students.

    ERIC Educational Resources Information Center

    Ehindero, Olusola Joseph

    1979-01-01

    Compares the performances on a battery of six Piagetian tasks of 80 Nigerian high school students classified as high and low achievers in biology. The relationship between performance of very bright biology students (high achievers) and intellectual precocity is also investigated. (HM)

  17. The role of reliability graph models in assuring dependable operation of complex hardware/software systems

    NASA Technical Reports Server (NTRS)

    Patterson-Hine, F. A.; Davis, Gloria J.; Pedar, A.

    1991-01-01

    The complexity of computer systems currently being designed for critical applications in the scientific, commercial, and military arenas requires the development of new techniques for utilizing models of system behavior in order to assure 'ultra-dependability'. The complexity of these systems, such as Space Station Freedom and the Air Traffic Control System, stems from their highly integrated designs containing both hardware and software as critical components. Reliability graph models, such as fault trees and digraphs, are used frequently to model hardware systems. Their applicability for software systems has also been demonstrated for software safety analysis and the analysis of software fault tolerance. This paper discusses further uses of graph models in the design and implementation of fault management systems for safety critical applications.

  18. Method and algorithm of ranking boiler plants at block electric power stations by the criterion of operation reliability and profitability

    NASA Astrophysics Data System (ADS)

    Farhadzadeh, E. M.; Muradaliyev, A. Z.; Farzaliyev, Y. Z.

    2015-10-01

    A method and an algorithm of ranking of boiler installations based on their technical and economic indicators are proposed. One of the basic conditions for ranking is the independence of technical and economic indicators. The assessment of their interrelation was carried out with respect to the correlation rate. The analysis of calculation data has shown that the interrelation stability with respect to the value and sign persists only for those indicators that have an evident relationship between each other. One of the calculation steps is the normalization of quantitative estimates of technical and economic indicators, which makes it possible to eliminate differences in dimensions and indicator units. The analysis of the known methods of normalization has allowed one to recommend the relative deviation from the average value as a normalized value and to use the arithmetic mean of the normalized values of independent indicators of each boiler installation as an integrated index of performance reliability and profitability. The fundamental differences from the existing approach to assess the "weak components" of a boiler installation and the quality of monitoring of its operating regimes are that the given approach takes into account the reliability and profitability of the operation of all other analogous boiler installations of an electric power station; it also implements competing elements with respect to the quality of control among the operating personnel of separate boiler installations and is aimed at encouraging an increased quality of maintenance and repairs.

  19. Iterative optical vector-matrix processors (survey of selected achievable operations)

    NASA Technical Reports Server (NTRS)

    Casasent, D.; Neuman, C.

    1981-01-01

    An iterative optical vector-matrix multiplier with a microprocessor-controlled feedback loop capable of performing a wealth of diverse operations was described. A survey and description of many of its operations demonstrates the versatility and flexibility of this class of optical processor and its use in diverse applications. General operations described include: linear difference and differential equations, linear algebraic equations, matrix equations, matrix inversion, nonlinear matrix equations, deconvolution and eigenvalue and eigenvector computations. Engineering applications being addressed for these different operations and for the IOP are: adaptive phased-array radar, time-dependent system modeling, deconvolution and optimal control.

  20. Comparing Pre- and Post-Operative Fontan Hemodynamic Simulations: Implications for the Reliability of Surgical Planning

    PubMed Central

    Haggerty, Christopher M.; de Zélicourt, Diane A.; Restrepo, Maria; Rossignac, Jarek; Spray, Thomas L.; Kanter, Kirk R.; Fogel, Mark A.; Yoganathan, Ajit P.

    2012-01-01

    Background Virtual modeling of cardiothoracic surgery is a new paradigm that allows for systematic exploration of various operative strategies and uses engineering principles to predict the optimal patient-specific plan. This study investigates the predictive accuracy of such methods for the surgical palliation of single ventricle heart defects. Methods Computational fluid dynamics (CFD)-based surgical planning was used to model the Fontan procedure for four patients prior to surgery. The objective for each was to identify the operative strategy that best distributed hepatic blood flow to the pulmonary arteries. Post-operative magnetic resonance data were acquired to compare (via CFD) the post-operative hemodynamics with predictions. Results Despite variations in physiologic boundary conditions (e.g., cardiac output, venous flows) and the exact geometry of the surgical baffle, sufficient agreement was observed with respect to hepatic flow distribution (90% confidence interval-14 ± 4.3% difference). There was also good agreement of flow-normalized energetic efficiency predictions (19 ± 4.8% error). Conclusions The hemodynamic outcomes of prospective patient-specific surgical planning of the Fontan procedure are described for the first time with good quantitative comparisons between preoperatively predicted and postoperative simulations. These results demonstrate that surgical planning can be a useful tool for single ventricle cardiothoracic surgery with the ability to deliver significant clinical impact. PMID:22777126

  1. An Initiative Toward Reliable Long-Duration Operation of Diode Lasers in Space

    NASA Technical Reports Server (NTRS)

    Tratt, David M.; Amzajerdian, Farzin; Stephen, Mark A.; Shapiro, Andrew A.

    2006-01-01

    This viewgraph presentation reviews the workings of the Laser Diode Arrays (LDA) working group. The group facilitates focused interaction between the LDA user and provider communities and it will author standards document for the specification and qualification of LDA's for operation in the space environment. It also reviews the NASA test and evaluation facilities that are available to the community.

  2. NOAA Operational Model Archive Distribution System (NOMADS): High Availability Applications for Reliable Real Time Access to Operational Model Data

    NASA Astrophysics Data System (ADS)

    Alpert, J. C.; Wang, J.

    2009-12-01

    To reduce the impact of natural hazards and environmental changes, the National Centers for Environmental Prediction (NCEP) provide first alert and a preferred partner for environmental prediction services, and represents a critical national resource to operational and research communities affected by climate, weather and water. NOMADS is now delivering high availability services as part of NOAA’s official real time data dissemination at its Web Operations Center (WOC) server. The WOC is a web service used by organizational units in and outside NOAA, and acts as a data repository where public information can be posted to a secure and scalable content server. A goal is to foster collaborations among the research and education communities, value added retailers, and public access for science and development efforts aimed at advancing modeling and GEO-related tasks. The user (client) executes what is efficient to execute on the client and the server efficiently provides format independent access services. Client applications can execute on the server, if it is desired, but the same program can be executed on the client side with no loss of efficiency. In this way this paradigm lends itself to aggregation servers that act as servers of servers listing, searching catalogs of holdings, data mining, and updating information from the metadata descriptions that enable collections of data in disparate places to be simultaneously accessed, with results processed on servers and clients to produce a needed answer. The services used to access the operational model data output are the Open-source Project for a Network Data Access Protocol (OPeNDAP), implemented with the Grid Analysis and Display System (GrADS) Data Server (GDS), and applications for slicing, dicing and area sub-setting the large matrix of real time model data holdings. This approach insures an efficient use of computer resources because users transmit/receive only the data necessary for their tasks including

  3. Review and evaluation of Transamerica Delaval, Inc. , diesel engine reliability and operability: Grand Gulf Nuclear Station Unit 1

    SciTech Connect

    Not Available

    1984-07-01

    PNL and its consultants conclude that the TDI diesel engines at the GGNS have the needed operability and reliability to fulfill their intended (auxiliary) emergency power function for the first refueling cycle. This conclusion is reached with a number of understandings regarding limits to the engine requirements, NRC concurrence with MP and L findings/conclusions regarding items to be supplied to NRC, limitations on the engine Brake Mean Effective Pressure (BMEP), and MP and L's implementation of the modifications to their proposed surveillance and maintenance program.

  4. Leveraging Naval Riverine Forces to Achieve Information Superiority in Stability Operations

    DTIC Science & Technology

    2010-12-01

    countryside around the clock in the hope of spotting insurgents burying bombs or setting up ambushes.” While single events such as these can give the...operations: Operation Iraqi freedom initial impressions report ( IIR ). Retrieved February 4, 2010 from George Town, Grand Cayman: Public

  5. Practical Aspects of Repository Operations for the Software Technology for Adaptable, Reliable Systems

    DTIC Science & Technology

    1990-01-10

    compatibility across a wide performance range of CPU platforms from approximately one MIPS up to 30 MIPS. The VAX central processing unit is a complex...cannot be understated. The goal of repository operation is to design and provide a system which can be understood, used, and accessed by an average user...edit function into the other software products, but imposes a choice upon users. Such decisions and trade-offs are common in repository design . Each

  6. Hanford high level waste (HLW) tank mixer pump safe operating envelope reliability assessment

    SciTech Connect

    Fischer, S.R.; Clark, J.

    1993-10-01

    The US Department of Energy and its contractor, Westinghouse Corp., are responsible for the management and safe storage of waste accumulated from processing defense reactor irradiated fuels for plutonium recovery at the Hanford Site. These wastes, which consist of liquids and precipitated solids, are stored in underground storage tanks pending final disposition. Currently, 23 waste tanks have been placed on a safety watch list because of their potential for generating, storing, and periodically releasing various quantities of hydrogen and other gases. Tank 101-SY in the Hanford SY Tank Farm has been found to release hydrogen concentrations greater than the lower flammable limit (LFL) during periodic gas release events. In the unlikely event that an ignition source is present during a hydrogen release, a hydrogen burn could occur with a potential to release nuclear waste materials. To mitigate the periodic gas releases occurring from Tank 101-SY, a large mixer pump currently is being installed in the tank to promote a sustained release of hydrogen gas to the tank dome space. An extensive safety analysis (SA) effort was undertaken and documented to ensure the safe operation of the mixer pump after it is installed in Tank 101-SY.1 The SA identified a need for detailed operating, alarm, and abort limits to ensure that analyzed safety limits were not exceeded during pump operations.

  7. Summary of the Optics, IR, Injection, Operations, Reliability and Instrumentation Working Group

    SciTech Connect

    Wienands, U.; Funakoshi, Y.; /KEK, Tsukuba

    2012-04-20

    The facilities reported on are all in a fairly mature state of operation, as evidenced by the very detailed studies and correction schemes that all groups are working on. First- and higher-order aberrations are diagnosed and planned to be corrected. Very detailed beam measurements are done to get a global picture of the beam dynamics. More than other facilities the high-luminosity colliders are struggling with experimental background issues, mitigation of which is a permanent challenge. The working group dealt with a very wide rage of practical issues which limit performance of the machines and compared their techniques of operations and their performance. We anticipate this to be a first attempt. In a future workshop in this series, we propose to attempt more fundamental comparisons of each machine, including design parameters. For example, DAPHNE and KEKB employ a finite crossing angle. The minimum value of {beta}*{sub y} attainable at KEKB seems to relate to this scheme. Effectiveness of compensation solenoids and turn-by-turn BPMs etc. should be examined in more detail. In the near future, CESR-C and VEPP-2000 will start their operation. We expect to hear important new experiences from these machines; in particular VEPP-2000 will be the first machine to have adopted round beams. At SLAC and KEK, next generation B Factories are being considered. It will be worthwhile to discuss the design issues of these machines based on the experiences of the existing factory machines.

  8. Highly reliable wind-rolling triboelectric nanogenerator operating in a wide wind speed range

    NASA Astrophysics Data System (ADS)

    Yong, Hyungseok; Chung, Jihoon; Choi, Dukhyun; Jung, Daewoong; Cho, Minhaeng; Lee, Sangmin

    2016-09-01

    Triboelectric nanogenerators are aspiring energy harvesting methods that generate electricity from the triboelectric effect and electrostatic induction. This study demonstrates the harvesting of wind energy by a wind-rolling triboelectric nanogenerator (WR-TENG). The WR-TENG generates electricity from wind as a lightweight dielectric sphere rotates along the vortex whistle substrate. Increasing the kinetic energy of a dielectric converted from the wind energy is a key factor in fabricating an efficient WR-TENG. Computation fluid dynamics (CFD) analysis is introduced to estimate the precise movements of wind flow and to create a vortex flow by adjusting the parameters of the vortex whistle shape to optimize the design parameters to increase the kinetic energy conversion rate. WR-TENG can be utilized as both a self-powered wind velocity sensor and a wind energy harvester. A single unit of WR-TENG produces open-circuit voltage of 11.2 V and closed-circuit current of 1.86 μA. Additionally, findings reveal that the electrical power is enhanced through multiple electrode patterns in a single device and by increasing the number of dielectric spheres inside WR-TENG. The wind-rolling TENG is a novel approach for a sustainable wind-driven TENG that is sensitive and reliable to wind flows to harvest wasted wind energy in the near future.

  9. Highly reliable wind-rolling triboelectric nanogenerator operating in a wide wind speed range.

    PubMed

    Yong, Hyungseok; Chung, Jihoon; Choi, Dukhyun; Jung, Daewoong; Cho, Minhaeng; Lee, Sangmin

    2016-09-22

    Triboelectric nanogenerators are aspiring energy harvesting methods that generate electricity from the triboelectric effect and electrostatic induction. This study demonstrates the harvesting of wind energy by a wind-rolling triboelectric nanogenerator (WR-TENG). The WR-TENG generates electricity from wind as a lightweight dielectric sphere rotates along the vortex whistle substrate. Increasing the kinetic energy of a dielectric converted from the wind energy is a key factor in fabricating an efficient WR-TENG. Computation fluid dynamics (CFD) analysis is introduced to estimate the precise movements of wind flow and to create a vortex flow by adjusting the parameters of the vortex whistle shape to optimize the design parameters to increase the kinetic energy conversion rate. WR-TENG can be utilized as both a self-powered wind velocity sensor and a wind energy harvester. A single unit of WR-TENG produces open-circuit voltage of 11.2 V and closed-circuit current of 1.86 μA. Additionally, findings reveal that the electrical power is enhanced through multiple electrode patterns in a single device and by increasing the number of dielectric spheres inside WR-TENG. The wind-rolling TENG is a novel approach for a sustainable wind-driven TENG that is sensitive and reliable to wind flows to harvest wasted wind energy in the near future.

  10. Highly reliable wind-rolling triboelectric nanogenerator operating in a wide wind speed range

    PubMed Central

    Yong, Hyungseok; Chung, Jihoon; Choi, Dukhyun; Jung, Daewoong; Cho, Minhaeng; Lee, Sangmin

    2016-01-01

    Triboelectric nanogenerators are aspiring energy harvesting methods that generate electricity from the triboelectric effect and electrostatic induction. This study demonstrates the harvesting of wind energy by a wind-rolling triboelectric nanogenerator (WR-TENG). The WR-TENG generates electricity from wind as a lightweight dielectric sphere rotates along the vortex whistle substrate. Increasing the kinetic energy of a dielectric converted from the wind energy is a key factor in fabricating an efficient WR-TENG. Computation fluid dynamics (CFD) analysis is introduced to estimate the precise movements of wind flow and to create a vortex flow by adjusting the parameters of the vortex whistle shape to optimize the design parameters to increase the kinetic energy conversion rate. WR-TENG can be utilized as both a self-powered wind velocity sensor and a wind energy harvester. A single unit of WR-TENG produces open-circuit voltage of 11.2 V and closed-circuit current of 1.86 μA. Additionally, findings reveal that the electrical power is enhanced through multiple electrode patterns in a single device and by increasing the number of dielectric spheres inside WR-TENG. The wind-rolling TENG is a novel approach for a sustainable wind-driven TENG that is sensitive and reliable to wind flows to harvest wasted wind energy in the near future. PMID:27653976

  11. A reliable and efficient method for deleting operational sequences in PACs and BACs.

    PubMed

    Nistala, Ravi; Sigmund, Curt D

    2002-05-15

    P1-derived artificial chromosomes (PACs) and bacterial artificial chromosomes (BACs) have become very useful as tools to study gene expression and regulation in cells and in transgenic mice. They carry large fragments of genomic DNA (> or =100 kb) and therefore may contain all of the cis-regulatory elements required for expression of a gene. Because of this, even when inserted randomly in the genome, they can emulate the native environment of a gene resulting in a tightly regulated pattern of expression. Because these large genomic clones often contain DNA sequences which can manipulate chromatin at the local level, they become immune to position effects which affect expression of smaller transgenes, and thus their expression is proportional to copy number. Transgenic mice containing large BACs and PACs have become excellent models to examine the regulation of gene expression. Their usefulness would certainly be increased if easy and efficient methods are developed to manipulate them. We describe herein a method to make deletion mutations reliably and efficiently using a novel modification of the Chi-stimulated homologous recombination method. Specifically, we generated and employed a Lox511 'floxed' CAM resistance marker that first affords selection for homologous recombination in Escherichia coli, and then can be easily deleted leaving only a single Lox511 site as the footprint.

  12. The visual stress model—A psycho-physiological method for the evaluation of operational reliability of pilots and cosmonauts

    NASA Astrophysics Data System (ADS)

    Kammel, H.; Haase, H.

    An experimental psycho-physiological method is presented for the evaluation of visual-cognitive performance preconditions and operational reliability of pilots and cosmonauts. As visual-cognitive stress are used tachistoscopically presented instrument symbols under conditions of individual speed of work and time pressure. The results of the compared extreme groups consisting of pilots with good and insufficient flight performance showed that the pilots with impairments to the quality of flight activity differ already before the test in their individual habitual characteristics and actual motivation, during the stress in their operational parameters, in the dimensions of their cardiorespiratory activation as well as in their efficiency and after the stress in their subjective experience of the stress. Conclusions are drawn for the evaluation of the aptitude of pilots and cosmonauts.

  13. A highly reliable, high performance open avionics architecture for real time Nap-of-the-Earth operations

    NASA Technical Reports Server (NTRS)

    Harper, Richard E.; Elks, Carl

    1995-01-01

    An Army Fault Tolerant Architecture (AFTA) has been developed to meet real-time fault tolerant processing requirements of future Army applications. AFTA is the enabling technology that will allow the Army to configure existing processors and other hardware to provide high throughput and ultrahigh reliability necessary for TF/TA/NOE flight control and other advanced Army applications. A comprehensive conceptual study of AFTA has been completed that addresses a wide range of issues including requirements, architecture, hardware, software, testability, producibility, analytical models, validation and verification, common mode faults, VHDL, and a fault tolerant data bus. A Brassboard AFTA for demonstration and validation has been fabricated, and two operating systems and a flight-critical Army application have been ported to it. Detailed performance measurements have been made of fault tolerance and operating system overheads while AFTA was executing the flight application in the presence of faults.

  14. Aircraft Carrier Operations at Sea: The Challenges of High Reliability Performance

    DTIC Science & Technology

    1988-07-29

    106 WI-mý 1-----ý2 .L-rwý-2ra.-tLl-p ý ’!?I -21 --g )l-.- q-_; w-ýp-I -- ý -ýý - Table of Contents 1. Introduction and Overview 2. Concepts and...requisites for and limitations of attaining nearly failure-free operations in large scale organizations; and an improved empirical understanding of... empirical conditions associatedJ with successfully attaining what appears on its face to be a nearly impossible requirement? I Attaining nearly failure

  15. Overall Key Performance Indicator to Optimizing Operation of High-Pressure Homogenizers for a Reliable Quantification of Intracellular Components in Pichia pastoris.

    PubMed

    Garcia-Ortega, Xavier; Reyes, Cecilia; Montesinos, José Luis; Valero, Francisco

    2015-01-01

    The most commonly used cell disruption procedures may present lack of reproducibility, which introduces significant errors in the quantification of intracellular components. In this work, an approach consisting in the definition of an overall key performance indicator (KPI) was implemented for a lab scale high-pressure homogenizer (HPH) in order to determine the disruption settings that allow the reliable quantification of a wide sort of intracellular components. This innovative KPI was based on the combination of three independent reporting indicators: decrease of absorbance, release of total protein, and release of alkaline phosphatase activity. The yeast Pichia pastoris growing on methanol was selected as model microorganism due to it presents an important widening of the cell wall needing more severe methods and operating conditions than Escherichia coli and Saccharomyces cerevisiae. From the outcome of the reporting indicators, the cell disruption efficiency achieved using HPH was about fourfold higher than other lab standard cell disruption methodologies, such bead milling cell permeabilization. This approach was also applied to a pilot plant scale HPH validating the methodology in a scale-up of the disruption process. This innovative non-complex approach developed to evaluate the efficacy of a disruption procedure or equipment can be easily applied to optimize the most common disruption processes, in order to reach not only reliable quantification but also recovery of intracellular components from cell factories of interest.

  16. Design and Varactors: Operational Considerations. A Reliability Study for Robust Planar GaAs

    NASA Technical Reports Server (NTRS)

    Maiwald, Frank; Schlecht, Erich; Ward, John; Lin, Robert; Leon, Rosa; Pearson, John; Mehdi, Imran

    2003-01-01

    Preliminary conclusions include: Limits for reverse currents cannot be set. Based on current data we want to avoid any reverse bias current. We know 1 micro-A is too high. Leakage current gets suppressed when operated at 120K. Migration and verification: a) Reverse Bias Voltage will be limited; b) Health check with I/V curve: 1) Minimal reverse voltage shall be x0.75 of the calculated voltage breakdown Vbr; 2) Degradation of the Reverse Bias voltage at given current will be used as indication of ESD incidents or other Damages (high RF power, heat); 3) Calculation of diodes parameter to verify initial health check result in forward direction. RF output power starts to degrade when diode I/V curve is very strongly degraded only. Experienced on 400GHz doubler and 200GHz doubler

  17. Unconventional Warfare and Operational Art: Can We Achieve Continuity in Command and Control?

    DTIC Science & Technology

    2007-11-02

    THREE: UW AND SENGE’S LEARNING DISABILITIES , AN ANALYSIS....... 27 CHAPTER FOUR: CONCLUSION AND RECOMMENDATIONS ..........Error! Bookmark not defined...legitimacy and relevancy of unconventional warfare in achieving the nation’s goals. The Seven Learning Disabilities from Peter Senge’s The Fifth Discipline...the Seven Learning Disabilities . The book describes seven deficiencies that might identify whether or not an organization is a learning

  18. Reliability Analysis of Drilling Operation in Open Pit Mines / Analiza niezawodności urządzeń wiertniczych wykorzystywanych w kopalniach odkrywkowych

    NASA Astrophysics Data System (ADS)

    Rahimdel, M. J.; Ataei, M.; Kakaei, R.; Hoseinie, S. H.

    2013-06-01

    Considering the high investment and operation costs, reliability analysis of mining machineries is essential to achieve a lean operation and to prevent the unwanted stoppages. In open pit mining, drilling, as the initial stage of the exploitation operations, has a significant role in the other stages. Failure of drilling machines causes total delay in blasting operation. In this paper, the reliability of drilling operation has been analyzed using the Markov method. The failure and operation data of four heavy rotary drilling machines in Sarcheshme copper mine in Iran have been used as a case study. Failure rate and repair rate of all machines have been calculated using available data. Then, 16 possible operation states have been defined and the probability of being of drilling fleet in each of the states was calculated using Markov theory. The results showed that there was 77.2% probability that all machines in fleet were in operational condition. It means that, considering 360 working days per year, drilling operation will be in a reliable condition in 277.92 days. Biorąc pod uwagę wysokość kosztów inwestycyjnych a także eksploatacyjnych, przeprowadzenie analizy niezawodności maszyn i urządzeń górniczych jest sprawą kluczową dla zapewnienia sprawnego działania i dla wyeliminowania niepożądanych przestojów. W kopalniach odkrywkowych prace wiertnicze prowadzone w początkowych etapach eksploatacji mają ogromne znaczenie również w późniejszych fazach działalności przedsięwzięcia. Awaria urządzeń wiertniczych powoduje opóźnienia przy pracach strzałowych. W pracy tej przeanalizowano niezawodność urządzeń wiertniczych w oparciu o metodę Markowa. Jako studium przypadku wykorzystano dane zebrane w trakcie eksploatacji i awarii czterech obrotowych urządzeń wiertniczych wykorzystywanych w kopalni rud miedzi Sarcheshme w Iranie. Awaryjność maszyn i zakres oraz częstość napraw obliczono na podstawie dostępnych danych. Zdefiniowano 16

  19. Factors in reliable treatment plant operation for the production of safe water.

    PubMed

    Hendry, Bruce A

    2010-08-01

    This contribution to the International Congress on Production of Safe Water, Izmir, Turkey, 20-24 January, 2009, relates to general aspects of a water supply undertaking rather than to particular technologies or chemistries for water treatment. The paper offers a "creative problem solving" approach following Fogler and LeBlanc (Strategies for creative problem solving. Prentice Hall, NJ, 1995) as a model for generating sustainable solutions when water quality and safety problems arise. Such a structured approach presents a systematic methodology that can promote communication and goal-sharing across the inter-related, but often isolated and dispersed, functions of water scientists and researchers, engineers, operations managers, government departments and communities. A problem-solving strategy, or "heuristic", invokes five main steps (define; generate; decide; implement; evaluate). Associated with each step are various creative and enabling techniques, many of which are quite familiar to us in one form or another, but which we can use more effectively in combination and through our increased awareness and practice. For example, taking a fresh view of a problem can be promoted by a variety of "lateral thinking" tools. First-hand investigation of a problem can trigger new thinking about the real problem and its origins. A good strategy implementation will always address each and every step (though not necessarily every possible technique) and will use them at various stages in the search for and implementation of solutions. The creative nature of our experience with a problem-solving heuristic develops our facility to cope better with complex formal situations, as well as with less formal or everyday problem situations. A few anecdotes are presented that illustrate some of the author's experiences relating to factors involved in safe water supply. Here, the term "factors" may signify people and organisations as agents, as well as meaning those aspects of a problem

  20. Are surgical scrubbing and pre-operative disinfection of the skin in orthopaedic surgery reliable?

    PubMed

    Salvi, M; Chelo, C; Caputo, F; Conte, M; Fontana, C; Peddis, G; Velluti, C

    2006-01-01

    This study attempts to establish the actual effectiveness of pre-surgical disinfection of the patient and surgeon's hands. We evaluated bacterial density and composition on the skin of 15 patients undergoing knee arthroscopy and the left hand of two surgeons after standard disinfection with povidone-iodine. Three samples were taken after the first 6-min scrub in the first surgical operation from the periungual space of the 1 degrees finger, from the interdigital space between the 2 degrees and 3 degrees fingers and from the transverse palmar crest of the left hand of two surgeons for seven consecutive surgical sessions, for a total of 42 samples, and two samples from the pre-patellar skin and from the popliteal skin of 15 patients undergoing knee arthroscopy, for a total of 30 samples. Pre-surgical handwashing and disinfection procedures were identical in each case. Pre-surgical disinfection of the patient's skin with povidone-iodine was shown to be completely effective, with 100% of samples negative. Samples taken from the interdigital space and the palmar crest (100% of samples negative) demonstrated the efficacy of disinfection of the surgeon's hands with povidone-iodine, while the periungual space was contaminated in 50% of the samples. The bacterial strains isolated belong to the staphylococcus genus in 100% of the cases, with pathogenic strains in 29.6% of the cases. Standard pre-surgical disinfection of skin in areas easily accessible to the disinfectant is sufficient in itself to guarantee thorough sanitization. Standard scrubbing of the surgeon's hands is insufficient in eliminating bacterial contamination, including pathogenic germs, in the periungual space, where it is probably difficult for the disinfectant to come into contact with the skin.

  1. Advanced, Integrated Control for Building Operations to Achieve 40% Energy Saving

    SciTech Connect

    Lu, Yan; Song, Zhen; Loftness, Vivian; Ji, Kun; Zheng, Sam; Lasternas, Bertrand; Marion, Flore; Yuebin, Yu

    2012-10-15

    We developed and demonstrated a software based integrated advanced building control platform called Smart Energy Box (SEB), which can coordinate building subsystem controls, integrate variety of energy optimization algorithms and provide proactive and collaborative energy management and control for building operations using weather and occupancy information. The integrated control system is a low cost solution and also features: Scalable component based architecture allows to build a solution for different building control system configurations with needed components; Open Architecture with a central data repository for data exchange among runtime components; Extendible to accommodate variety of communication protocols. Optimal building control for central loads, distributed loads and onsite energy resource; uses web server as a loosely coupled way to engage both building operators and building occupants in collaboration for energy conservation. Based on the open platform of SEB, we have investigated and evaluated a variety of operation and energy saving control strategies on Carnegie Mellon University Intelligent Work place which is equipped with alternative cooling/heating/ventilation/lighting methods, including radiant mullions, radiant cooling/heating ceiling panels, cool waves, dedicated ventilation unit, motorized window and blinds, and external louvers. Based on the validation results of these control strategies, they were integrated in SEB in a collaborative and dynamic way. This advanced control system was programmed and computer tested with a model of the Intelligent Workplace's northern section (IWn). The advanced control program was then installed in the IWn control system; the performance was measured and compared with that of the state of the art control system to verify the overall energy savings great than 40%. In addition advanced human machine interfaces (HMI's) were developed to communicate both with building occupants and

  2. Defense Commissaries: DOD Needs to Improve Business Processes to Ensure Patron Benefits and Achieve Operational Efficiencies

    DTIC Science & Technology

    2017-03-01

    cost of business operations, competition in their market , and the need to generate a profit. In addition, different product distribution options... market conditions such as local labor costs as would be true for a commercial grocery store. Figure 1 shows how DeCA allocated $1.3 billion in...savings rate is calculated as a weighted average based on the market shares from sales in the previous fiscal year

  3. O&M Best Practices - A Guide to Achieving Operational Efficiency (Release 2.0)

    SciTech Connect

    Sullivan, Gregory P.; Pugh, Ray; Melendez, Aldo P.; Hunt, W. D.

    2004-07-31

    This guide, sponsored by DOE's Federal Energy Management Program, highlights operations and maintenance (O&M) programs targeting energy efficiency that are estimated to save 5% to 20% on energy bills without a significant capital investment. The purpose of this guide is to provide the federal O&M energy manager and practitioner with useful information about O&M management, technologies, energy efficiency and cost-reduction approaches.

  4. Naval Readiness, Operational Training, and Environmental Protection: Achieving an Appropriate Balance between Competing National Interests

    DTIC Science & Technology

    1988-06-01

    Readiness: Operational Traininz; Polution 19 ABSTRACT (Continue on reverse if necessary and identify by block number) This paper describes the...Education Command (Quantico, Virginia); Washington Navy Yard, Naval Air Stations Patuxent River % . (Maryland), Bermuda and Keflavik (Iceland); Marine...Corps Air Station lwakuni (Japan); U.S. Naval Base Yokosuka (Japan); =.nd on Okinawa (Japan). The author holds a Bachelor of Science from the United

  5. Force of Choice: Optimizing Theater Special Operations Commands to Achieve Synchronized Effects

    DTIC Science & Technology

    2012-12-01

    AO/AOR Area of Operations/ Area of Responsibility AQIM Al Qaeda in the Islamic Maghreb BILAT Bilateral Exchange Training BPC Build Partner...partners is made more difficult.110 For example, in many cases, multiple JCET’s over a period of time are used for build partner capacity ( BPC ...Since by law the JCET’s must result in U.S. SOF gaining the most training value, the BPC activities are a residual result of the JCET.111 Admittedly

  6. The use of ECDIS equipment to achieve an optimum value for energy efficiency operation index

    NASA Astrophysics Data System (ADS)

    Acomi, N.; Acomi, O. C.; Stanca, C.

    2015-11-01

    To reduce air pollution produced by ships, the International Maritime Organization has developed a set of technical, operational and management measures. The subject of our research addresses the operational measures for minimizing CO2 air emissions and the way how the emission value could be influenced by external factors regardless of ship-owners’ will. This study aims to analyse the air emissions for a loaded voyage leg performed by an oil tanker. The formula that allows us to calculate the predicted Energy Efficiency Operational Index involves the estimation of distance and fuel consumption, while the quantity of cargo is known. The electronic chart display and information system, ECDIS Simulation Software, will be used for adjusting the passage plan in real time, given the predicted severe environmental conditions. The distance will be determined using ECDIS, while the prediction of the fuel consumption will consider the sea trial and the vessel experience records. That way it will be possible to compare the estimated EEOI value in the case of great circle navigation in adverse weather condition with the estimated EEOI value for weather navigation.

  7. The ALMA high speed optical communication link is here: an essential component for reliable present and future operations

    NASA Astrophysics Data System (ADS)

    Filippi, G.; Ibsen, J.; Jaque, S.; Liello, F.; Ovando, N.; Astudillo, A.; Parra, J.; Saldias, Christian

    2016-07-01

    Announced in 2012, started in 2013 and completed in 2015, the ALMA high bandwidth communication system has become a key factor to achieve the operational and scientific goals of ALMA. This paper summarizes the technical, organizational, and operational goals of the ALMA Optical Link Project, focused in the creation and operation of an effective and sustainable communication infrastructure to connect the ALMA Operations Support Facility and Array Operations Site, both located in the Atacama Desert in the Northern region of Chile, with the point of presence of REUNA in Antofagasta, about 400km away, and from there to the Santiago Central Office in the Chilean capital through the optical infrastructure created by the EC-funded EVALSO project and now an integral part of the REUNA backbone. This new infrastructure completed in 2014 and now operated on behalf of ALMA by REUNA, the Chilean National Research and Education Network, uses state of the art technologies, like dark fiber from newly built cables and DWDM transmission, allowing extending the reach of high capacity communication to the remote region where the Observatory is located. The paper also reports on the results obtained during the first year and a half testing and operation period, where different operational set ups have been experienced for data transfer, remote collaboration, etc. Finally, the authors will present a forward look of the impact of it to both the future scientific development of the Chajnantor Plateau, where many installations area are (and will be) located, as well as the potential Chilean scientific backbone long term development.

  8. Conceptual design study of advanced acoustic composite nacelle. [for achieving reductions in community noise and operating expense

    NASA Technical Reports Server (NTRS)

    Goodall, R. G.; Painter, G. W.

    1975-01-01

    Conceptual nacelle designs for wide-bodied and for advanced-technology transports were studied with the objective of achieving significant reductions in community noise with minimum penalties in airplane weight, cost, and in operating expense by the application of advanced composite materials to nacelle structure and sound suppression elements. Nacelle concepts using advanced liners, annular splitters, radial splitters, translating centerbody inlets, and mixed-flow nozzles were evaluated and a preferred concept selected. A preliminary design study of the selected concept, a mixed flow nacelle with extended inlet and no splitters, was conducted and the effects on noise, direct operating cost, and return on investment determined.

  9. Achieving high mobility, low-voltage operating organic field-effect transistor nonvolatile memory by an ultraviolet-ozone treating ferroelectric terpolymer

    NASA Astrophysics Data System (ADS)

    Xiang, Lanyi; Wang, Wei; Xie, Wenfa

    2016-11-01

    Poly(vinylidene fluoride–trifluoroethylene) has been widely used as a dielectric of the ferroelectric organic field-effect transistor (FE-OFET) nonvolatile memory (NVM). Some critical issues, including low mobility and high operation voltage, existed in these FE-OFET NVMs, should be resolved before considering to their commercial application. In this paper, we demonstrated low-voltage operating FE-OFET NVMs based on a ferroelectric terpolymer poly(vinylidene-fluoride-trifluoroethylene-chlorotrifluoroethylene) [P(VDF-TrFE-CTFE)] owed to its low coercive field. By applying an ultraviolet-ozone (UVO) treatment to modify the surface of P(VDF-TrFE-CTFE) films, the growth model of the pentacene film was changed, which improved the pentacene grain size and the interface morphology of the pentacene/P(VDF-TrFE-CTFE). Thus, the mobility of the FE-OFET was significantly improved. As a result, a high performance FE-OFET NVM, with a high mobility of 0.8 cm2 V‑1 s‑1, large memory window of 15.4~19.2, good memory on/off ratio of 103, the reliable memory endurance over 100 cycles and stable memory retention ability, was achieved at a low operation voltage of ±15 V.

  10. Achieving high mobility, low-voltage operating organic field-effect transistor nonvolatile memory by an ultraviolet-ozone treating ferroelectric terpolymer

    PubMed Central

    Xiang, Lanyi; Wang, Wei; Xie, Wenfa

    2016-01-01

    Poly(vinylidene fluoride–trifluoroethylene) has been widely used as a dielectric of the ferroelectric organic field-effect transistor (FE-OFET) nonvolatile memory (NVM). Some critical issues, including low mobility and high operation voltage, existed in these FE-OFET NVMs, should be resolved before considering to their commercial application. In this paper, we demonstrated low-voltage operating FE-OFET NVMs based on a ferroelectric terpolymer poly(vinylidene-fluoride-trifluoroethylene-chlorotrifluoroethylene) [P(VDF-TrFE-CTFE)] owed to its low coercive field. By applying an ultraviolet-ozone (UVO) treatment to modify the surface of P(VDF-TrFE-CTFE) films, the growth model of the pentacene film was changed, which improved the pentacene grain size and the interface morphology of the pentacene/P(VDF-TrFE-CTFE). Thus, the mobility of the FE-OFET was significantly improved. As a result, a high performance FE-OFET NVM, with a high mobility of 0.8 cm2 V−1 s−1, large memory window of 15.4~19.2, good memory on/off ratio of 103, the reliable memory endurance over 100 cycles and stable memory retention ability, was achieved at a low operation voltage of ±15 V. PMID:27824101

  11. The medial and lateral epicondyle as a reliable landmark for intra-operative joint line determination in revision knee arthroplasty

    PubMed Central

    Sen, T.; Cankaya, D.; Kendir, S.; Basarır, K.; Tabak, Y.

    2016-01-01

    Objectives The purpose of this study was to develop an accurate, reliable and easily applicable method for determining the anatomical location of the joint line during revision knee arthroplasty. Methods The transepicondylar width (TEW), the perpendicular distance between the medial and lateral epicondyles and the distal articular surfaces (DMAD, DLAD) and the distance between the medial and lateral epicondyles and the posterior articular surfaces (PMAD, DLAD) were measured in 40 knees from 20 formalin-fixed adult cadavers (11 male and nine female; mean age at death 56.9 years, sd 9.4; 34 to 69). The ratios of the DMAD, PMAD, DLAD and PLAD to TEW were calculated. Results The mean TEW, DMAD, PMAD, DLAD and PLAD were 82.76 mm (standard deviation (sd) 7.74), 28.95 mm (sd 3.3), 28.57 mm (sd 3), 23.97 mm (sd 3.27) and 24.42 mm (sd 3.14), respectively. The ratios between the TEW and the articular distances (DMAD/TEW, DLAD/TEW, PMAD/TEW and PLAD/TEW) were calculated and their means were 0.35 (sd 0.02), 0.34 (sd 0.02), 0.28 (sd 0.03) and 0.29 (sd 0.03), respectively. Conclusion This method provides a simple, reproducible and reliable technique enabling accurate anatomical joint line restoration during revision total knee arthroplasty. Cite this article: B. Ozkurt, T. Sen, D. Cankaya, S. Kendir, K. Basarır, Y. Tabak. The medial and lateral epicondyle as a reliable landmark for intra-operative joint line determination in revision knee arthroplasty. Bone Joint Res 2016;5:280–286. DOI: 10.1302/2046-3758.57.BJR-2016-0002.R1. PMID:27388715

  12. Copper-based micro-channel cooler reliably operated using solutions of distilled-water and ethanol as a coolant

    NASA Astrophysics Data System (ADS)

    Chin, A. K.; Nelson, A.; Chin, R. H.; Bertaska, R.; Jacob, J. H.

    2015-03-01

    Copper-based micro-channel coolers (Cu-MCC) are the lowest thermal-resistance heat-sinks for high-power laserdiode (LD) bars. Presently, the resistivity, pH and oxygen content of the de-ionized water coolant, must be actively controlled to minimize cooler failure by corrosion and electro-corrosion. Additionally, the water must be constantly exposed to ultraviolet radiation to limit the growth of micro-organisms that may clog the micro-channels. In this study, we report the reliable, care-free operation of LD-bars attached to Cu-MCCs, using a solution of distilledwater and ethanol as the coolant. This coolant meets the storage requirements of Mil-Std 810G, e.g. exposure to a storage temperature as low as -51°C and no growth of micro-organisms during passive storage.

  13. Design modification for the modular helium reactor for higher temperature operation and reliability studies for nuclear hydrogen production processes

    NASA Astrophysics Data System (ADS)

    Reza, S. M. Mohsin

    Design options have been evaluated for the Modular Helium Reactor (MHR) for higher temperature operation. An alternative configuration for the MHR coolant inlet flow path is developed to reduce the peak vessel temperature (PVT). The coolant inlet path is shifted from the annular path between reactor core barrel and vessel wall through the permanent side reflector (PSR). The number and dimensions of coolant holes are varied to optimize the pressure drop, the inlet velocity, and the percentage of graphite removed from the PSR to create this inlet path. With the removal of ˜10% of the graphite from PSR the PVT is reduced from 541°C to 421°C. A new design for the graphite block core has been evaluated and optimized to reduce the inlet coolant temperature with the aim of further reduction of PVT. The dimensions and number of fuel rods and coolant holes, and the triangular pitch have been changed and optimized. Different packing fractions for the new core design have been used to conserve the number of fuel particles. Thermal properties for the fuel elements are calculated and incorporated into these analyses. The inlet temperature, mass flow and bypass flow are optimized to limit the peak fuel temperature (PFT) within an acceptable range. Using both of these modifications together, the PVT is reduced to ˜350°C while keeping the outlet temperature at 950°C and maintaining the PFT within acceptable limits. The vessel and fuel temperatures during low pressure conduction cooldown and high pressure conduction cooldown transients are found to be well below the design limits. The reliability and availability studies for coupled nuclear hydrogen production processes based on the sulfur iodine thermochemical process and high temperature electrolysis process have been accomplished. The fault tree models for both these processes are developed. Using information obtained on system configuration, component failure probability, component repair time and system operating modes

  14. Reliability training

    NASA Technical Reports Server (NTRS)

    Lalli, Vincent R. (Editor); Malec, Henry A. (Editor); Dillard, Richard B.; Wong, Kam L.; Barber, Frank J.; Barina, Frank J.

    1992-01-01

    Discussed here is failure physics, the study of how products, hardware, software, and systems fail and what can be done about it. The intent is to impart useful information, to extend the limits of production capability, and to assist in achieving low cost reliable products. A review of reliability for the years 1940 to 2000 is given. Next, a review of mathematics is given as well as a description of what elements contribute to product failures. Basic reliability theory and the disciplines that allow us to control and eliminate failures are elucidated.

  15. Achieving operational two-way laser acquisition for OPALS payload on the International Space Station

    NASA Astrophysics Data System (ADS)

    Abrahamson, Matthew J.; Oaida, Bogdan V.; Sindiy, Oleg; Biswas, Abhijit

    2015-03-01

    The Optical PAyload for Lasercomm Science (OPALS) experiment was installed on the International Space Station (ISS) in April 2014. Developed as a technology demonstration, its objective was to experiment with space-to-ground optical communications transmissions from Low Earth Orbit. More than a dozen successful optical links were established between a Wrightwood, California-based ground telescope and the OPALS flight terminal from June 2014 to September 2014. Each transmission required precise bi-directional pointing to be maintained between the space-based transmitter and ground-based receiver. This was accomplished by acquiring and tracking a laser beacon signal transmitted from the ground telescope to the OPALS flight terminal on the ISS. OPALS demonstrated the ability to nominally acquire the beacon within three seconds at 25° elevation and maintain lock within 140 μrad (3σ) for the full 150-second transmission duration while slewing at rates up to 1°/sec. Additional acquisition attempts in low elevation and weather-challenged conditions provided valuable insight on the optical link robustness under off-nominal operational conditions.

  16. Use of Virtual Mission Operations Center Technology to Achieve JPDO's Virtual Tower Vision

    NASA Technical Reports Server (NTRS)

    Ivancic, William D.; Paulsen, Phillip E.

    2006-01-01

    The Joint Program Development Office has proposed that the Next Generation Air Transportation System (NGATS) consolidate control centers. NGATS would be managed from a few strategically located facilities with virtual towers and TRACONS. This consolidation is about combining the delivery locations for these services not about decreasing service. By consolidating these locations, cost savings in the order of $500 million have been projected. Evolving to spaced-based communication, navigation, and surveillance offers the opportunity to reduce or eliminate much of the ground-based infrastructure cost. Dynamically adjusted airspace offers the opportunity to reduce the number of sectors and boundary inconsistencies; eliminate or reduce "handoffs;" and eliminate the distinction between Towers, TRACONS, and Enroute Centers. To realize a consolidation vision for air traffic management there must be investment in networking. One technology that holds great potential is the use of Virtual Mission Operations Centers to provide secure, automated, intelligent management of the NGATS. This paper provides a conceptual framework for incorporating VMOC into the NGATS.

  17. Reliability assurance for regulation of advanced reactors

    SciTech Connect

    Fullwood, R.; Lofaro, R.; Samanta, P.

    1991-12-31

    The advanced nuclear power plants must achieve higher levels of safety than the first generation of plants. Showing that this is indeed true provides new challenges to reliability and risk assessment methods in the analysis of the designs employing passive and semi-passive protection. Reliability assurance of the advanced reactor systems is important for determining the safety of the design and for determining the plant operability. Safety is the primary concern, but operability is considered indicative of good and safe operation. This paper discusses several concerns for reliability assurance of the advanced design encompassing reliability determination, level of detail required in advanced reactor submittals, data for reliability assurance, systems interactions and common cause effects, passive component reliability, PRA-based configuration control system, and inspection, training, maintenance and test requirements. Suggested approaches are provided for addressing each of these topics.

  18. Proof-of-Concept Demonstrations for Computation-Based Human Reliability Analysis. Modeling Operator Performance During Flooding Scenarios

    SciTech Connect

    Joe, Jeffrey Clark; Boring, Ronald Laurids; Herberger, Sarah Elizabeth Marie; Mandelli, Diego; Smith, Curtis Lee

    2015-09-01

    The United States (U.S.) Department of Energy (DOE) Light Water Reactor Sustainability (LWRS) program has the overall objective to help sustain the existing commercial nuclear power plants (NPPs). To accomplish this program objective, there are multiple LWRS “pathways,” or research and development (R&D) focus areas. One LWRS focus area is called the Risk-Informed Safety Margin and Characterization (RISMC) pathway. Initial efforts under this pathway to combine probabilistic and plant multi-physics models to quantify safety margins and support business decisions also included HRA, but in a somewhat simplified manner. HRA experts at Idaho National Laboratory (INL) have been collaborating with other experts to develop a computational HRA approach, called the Human Unimodel for Nuclear Technology to Enhance Reliability (HUNTER), for inclusion into the RISMC framework. The basic premise of this research is to leverage applicable computational techniques, namely simulation and modeling, to develop and then, using RAVEN as a controller, seamlessly integrate virtual operator models (HUNTER) with 1) the dynamic computational MOOSE runtime environment that includes a full-scope plant model, and 2) the RISMC framework PRA models already in use. The HUNTER computational HRA approach is a hybrid approach that leverages past work from cognitive psychology, human performance modeling, and HRA, but it is also a significant departure from existing static and even dynamic HRA methods. This report is divided into five chapters that cover the development of an external flooding event test case and associated statistical modeling considerations.

  19. Robust fusion with reliabilities weights

    NASA Astrophysics Data System (ADS)

    Grandin, Jean-Francois; Marques, Miguel

    2002-03-01

    The reliability is a value of the degree of trust in a given measurement. We analyze and compare: ML (Classical Maximum Likelihood), MLE (Maximum Likelihood weighted by Entropy), MLR (Maximum Likelihood weighted by Reliability), MLRE (Maximum Likelihood weighted by Reliability and Entropy), DS (Credibility Plausibility), DSR (DS weighted by reliabilities). The analysis is based on a model of a dynamical fusion process. It is composed of three sensors, which have each it's own discriminatory capacity, reliability rate, unknown bias and measurement noise. The knowledge of uncertainties is also severely corrupted, in order to analyze the robustness of the different fusion operators. Two sensor models are used: the first type of sensor is able to estimate the probability of each elementary hypothesis (probabilistic masses), the second type of sensor delivers masses on union of elementary hypotheses (DS masses). In the second case probabilistic reasoning leads to sharing the mass abusively between elementary hypotheses. Compared to the classical ML or DS which achieves just 50% of correct classification in some experiments, DSR, MLE, MLR and MLRE reveals very good performances on all experiments (more than 80% of correct classification rate). The experiment was performed with large variations of the reliability coefficients for each sensor (from 0 to 1), and with large variations on the knowledge of these coefficients (from 0 0.8). All four operators reveal good robustness, but the MLR reveals to be uniformly dominant on all the experiments in the Bayesian case and achieves the best mean performance under incomplete a priori information.

  20. Validity, Reliability, and Performance Determinants of a New Job-Specific Anaerobic Work Capacity Test for the Norwegian Navy Special Operations Command.

    PubMed

    Angeltveit, Andreas; Paulsen, Gøran; Solberg, Paul A; Raastad, Truls

    2016-02-01

    Operators in Special Operation Forces (SOF) have a particularly demanding profession where physical and psychological capacities can be challenged to the extremes. The diversity of physical capacities needed depend on the mission. Consequently, tests used to monitor SOF operators' physical fitness should cover a broad range of physical capacities. Whereas tests for strength and aerobic endurance are established, there is no test for specific anaerobic work capacity described in the literature. The purpose of this study was therefore to evaluate the reliability, validity, and to identify performance determinants of a new test developed for testing specific anaerobic work capacity in SOF operators. Nineteen active young students were included in the concurrent validity part of the study. The students performed the evacuation (EVAC) test 3 times and the results were compared for reliability and with performance in the Wingate cycle test, 300-m sprint, and a maximal accumulated oxygen deficit (MAOD) test. In part II of the study, 21 Norwegian Navy Special Operations Command operators conducted the EVAC test, anthropometric measurements, a dual x-ray absorptiometry scan, leg press, isokinetic knee extensions, maximal oxygen uptake test, and countermovement jump (CMJ) test. The EVAC test showed good reliability after 1 familiarization trial (intraclass correlation = 0.89; coefficient of variance = 3.7%). The EVAC test correlated well with the Wingate test (r = -0.68), 300-m sprint time (r = 0.51), and 300-m mean power (W) (r = -0.67). No significant correlation was found with the MAOD test. In part II of the study, height, body mass, lean body mass, isokinetic knee extension torque, maximal oxygen uptake, and maximal power in a CMJ was significantly correlated with performance in the EVAC test. The EVAC test is a reliable and valid test for anaerobic work capacity for SOF operators, and muscle mass, leg strength, and leg power seem to be the most important determinants

  1. Field-Induced Crystalline-to-Amorphous Phase Transformation on the Si Nano-Apex and the Achieving of Highly Reliable Si Nano-Cathodes

    PubMed Central

    Huang, Yifeng; Deng, Zexiang; Wang, Weiliang; Liang, Chaolun; She, Juncong; Deng, Shaozhi; Xu, Ningsheng

    2015-01-01

    Nano-scale vacuum channel transistors possess merits of higher cutoff frequency and greater gain power as compared with the conventional solid-state transistors. The improvement in cathode reliability is one of the major challenges to obtain high performance vacuum channel transistors. We report the experimental findings and the physical insight into the field induced crystalline-to-amorphous phase transformation on the surface of the Si nano-cathode. The crystalline Si tip apex deformed to amorphous structure at a low macroscopic field (0.6~1.65 V/nm) with an ultra-low emission current (1~10 pA). First-principle calculation suggests that the strong electrostatic force exerting on the electrons in the surface lattices would take the account for the field-induced atomic migration that result in an amorphization. The arsenic-dopant in the Si surface lattice would increase the inner stress as well as the electron density, leading to a lower amorphization field. Highly reliable Si nano-cathodes were obtained by employing diamond like carbon coating to enhance the electron emission and thus decrease the surface charge accumulation. The findings are crucial for developing highly reliable Si-based nano-scale vacuum channel transistors and have the significance for future Si nano-electronic devices with narrow separation. PMID:25994377

  2. Achieving higher pathological complete response rates in HER-2-positive patients with induction chemotherapy without trastuzumab in operable breast cancer.

    PubMed

    Penault-Llorca, Frédérique; Abrial, Catherine; Mouret-Reynier, Marie-Ange; Raoelfils, Inès; Durando, Xavier; Leheurteur, Marianne; Gimbergues, Pierre; Tortochaux, Jacques; Curé, Hervé; Chollet, Philippe

    2007-04-01

    Recent trials of induction chemotherapy in bulky operable breast cancer have shown much higher pathological complete response (pCR) rates with trastuzumab-driven combinations. However, it is useful to take into account the specific chemosensitivity of HER-2-positive tumors. The aim of this study was to assess the pCR rate according to HER-2 status in response to chemotherapy, without an anti-HER-2 specific biological agent, in 710 operable breast cancer patients. Since 1982, these patients have been treated with several different neoadjuvant chemotherapy combinations. During this period, HER-2 overexpression was most often not assessed. Subsequently, we assessed HER-2 expression using archival paraffin-embedded tissue. A technically usable specimen was available for 413 of the 710 patients. Before treatment, 51 patients were HER-2 positive, 287 patients were HER-2 negative, and the results were inconclusive for 75 patients. Of these patients, a pCR in breast and nodes was obtained in 94 patients (14.3%), but this event was threefold more frequent for HER-2-positive patients (23.5%) than for HER-2-negative patients (7%). The overall survival (OS) and disease-free survival (DFS) rates at 10 years were 66.6% and 57.4%, respectively. The DFS rate was, as expected, better for HER-2-negative patients, with HER-2 status assessed before as well as after chemotherapy. A significant difference was found for OS in favor of HER-2-negative patients only with postchemotherapy assessment of HER-2, a fact similar to our previous findings. Finally, there was a tendency toward a higher DFS rate for HER-2-positive patients who achieved a pCR compared with HER-2-positive patients who did not.

  3. Inter-operator Reliability of Magnetic Resonance Image-Based Computational Fluid Dynamics Prediction of Cerebrospinal Fluid Motion in the Cervical Spine.

    PubMed

    Martin, Bryn A; Yiallourou, Theresia I; Pahlavian, Soroush Heidari; Thyagaraj, Suraj; Bunck, Alexander C; Loth, Francis; Sheffer, Daniel B; Kröger, Jan Robert; Stergiopulos, Nikolaos

    2016-05-01

    For the first time, inter-operator dependence of MRI based computational fluid dynamics (CFD) modeling of cerebrospinal fluid (CSF) in the cervical spinal subarachnoid space (SSS) is evaluated. In vivo MRI flow measurements and anatomy MRI images were obtained at the cervico-medullary junction of a healthy subject and a Chiari I malformation patient. 3D anatomies of the SSS were reconstructed by manual segmentation by four independent operators for both cases. CFD results were compared at nine axial locations along the SSS in terms of hydrodynamic and geometric parameters. Intraclass correlation (ICC) assessed the inter-operator agreement for each parameter over the axial locations and coefficient of variance (CV) compared the percentage of variance for each parameter between the operators. Greater operator dependence was found for the patient (0.19 < ICC < 0.99) near the craniovertebral junction compared to the healthy subject (ICC > 0.78). For the healthy subject, hydraulic diameter and Womersley number had the least variance (CV = ~2%). For the patient, peak diastolic velocity and Reynolds number had the smallest variance (CV = ~3%). These results show a high degree of inter-operator reliability for MRI-based CFD simulations of CSF flow in the cervical spine for healthy subjects and a lower degree of reliability for patients with Type I Chiari malformation.

  4. Spaceflight tracking and data network operational reliability computer output for MTBF and availability. Appendix V to CSC-1-395

    NASA Technical Reports Server (NTRS)

    Seneca, V. I.; Mlynarczyk, R. H.

    1974-01-01

    Tables of data are provided to show the availability of Skylab data to selected ground stations during the phases of Skylab preflight, Skylab unmanned condition, and Skylab manned condition. The mean time between failure (MTBF) of the same Skylab functions is tabulated for the selected ground stations. All reliability data are based on a 90 percent confidence interval.

  5. Reliable experimental setup to test the pressure modulation of Baerveldt Implant tubes for reducing post-operative hypotony

    NASA Astrophysics Data System (ADS)

    Ramani, Ajay

    Glaucoma encompasses a group of conditions that result in damage to the optic nerve and can cause loss of vision and blindness. The nerve is damaged due to an increase in the eye's internal (intraocular) pressure (IOP) above the nominal range of 15 -- 20 mm Hg. There are many treatments available for this group of diseases depending on the complexity and stage of nerve degradation. In extreme cases where drugs or laser surgery do not create better conditions for the patient, ophthalmologists use glaucoma drainage devices to help alleviate the IOP. Many drainage implants have been developed over the years and are in use; but two popular implants are the Baerveldt Glaucoma Implant and the Ahmed Glaucoma Valve Implant. Baerveldt Implants are non-valved and provide low initial resistance to outflow of fluid, resulting in post-operative complications such as hypotony, where the IOP drops below 5 mm of Hg. Ahmed Glaucoma Valve Implants are valved implants which initially restrict the amount of fluid flowing out of the eye. The long term success rates of Baerveldt Implants surpass those of Ahmed Valve Implants because of post-surgical issues; but Baerveldt Implants' initial effectiveness is poor without proper flow restriction. This drives the need to develop new ways to improve the initial effectiveness of Baerveldt Implants. A possible solution proposed by our research team is to place an insert in the Baerveldt Implant tube of inner diameter 305 microns. The insert must be designed to provide flow resistance for the early time frame [e.g., first 30 -- 60 post-operative days] until sufficient scar tissue has formed on the implant. After that initial stage with the insert, the scar tissue will provide the necessary flow resistance to maintain the IOP above 5 mm Hg. The main objective of this project was to develop and validate an experimental apparatus to measure pressure drop across a Baerveldt Implant tube, with and without inserts. This setup will be used in the

  6. The quadruple squeeze: defining the safe operating space for freshwater use to achieve a triply green revolution in the anthropocene.

    PubMed

    Rockström, Johan; Karlberg, Louise

    2010-05-01

    Humanity has entered a new phase of sustainability challenges, the Anthropocene, in which human development has reached a scale where it affects vital planetary processes. Under the pressure from a quadruple squeeze-from population and development pressures, the anthropogenic climate crisis, the anthropogenic ecosystem crisis, and the risk of deleterious tipping points in the Earth system-the degrees of freedom for sustainable human exploitation of planet Earth are severely restrained. It is in this reality that a new green revolution in world food production needs to occur, to attain food security and human development over the coming decades. Global freshwater resources are, and will increasingly be, a fundamental limiting factor in feeding the world. Current water vulnerabilities in the regions in most need of large agricultural productivity improvements are projected to increase under the pressure from global environmental change. The sustainability challenge for world agriculture has to be set within the new global sustainability context. We present new proposed sustainability criteria for world agriculture, where world food production systems are transformed in order to allow humanity to stay within the safe operating space of planetary boundaries. In order to secure global resilience and thereby raise the chances of planet Earth to remain in the current desired state, conducive for human development on the long-term, these planetary boundaries need to be respected. This calls for a triply green revolution, which not only more than doubles food production in many regions of the world, but which also is environmentally sustainable, and invests in the untapped opportunities to use green water in rainfed agriculture as a key source of future productivity enhancement. To achieve such a global transformation of agriculture, there is a need for more innovative options for water interventions at the landscape scale, accounting for both green and blue water, as well

  7. PV Systems Reliability Final Technical Report.

    SciTech Connect

    Lavrova, Olga; Flicker, Jack David; Johnson, Jay; Armijo, Kenneth Miguel; Gonzalez, Sigifredo; Schindelholz, Eric John; Sorensen, Neil R.; Yang, Benjamin Bing-Yeh

    2015-12-01

    The continued exponential growth of photovoltaic technologies paves a path to a solar-powered world, but requires continued progress toward low-cost, high-reliability, high-performance photovoltaic (PV) systems. High reliability is an essential element in achieving low-cost solar electricity by reducing operation and maintenance (O&M) costs and extending system lifetime and availability, but these attributes are difficult to verify at the time of installation. Utilities, financiers, homeowners, and planners are demanding this information in order to evaluate their financial risk as a prerequisite to large investments. Reliability research and development (R&D) is needed to build market confidence by improving product reliability and by improving predictions of system availability, O&M cost, and lifetime. This project is focused on understanding, predicting, and improving the reliability of PV systems. The two areas being pursued include PV arc-fault and ground fault issues, and inverter reliability.

  8. 76 FR 66328 - Callaway Golf Ball Operations, Inc., Including On-Site Leased Workers From Reliable Temp Services...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-10-26

    ... Employment and Training Administration Callaway Golf Ball Operations, Inc., Including On-Site Leased Workers..., 2011, applicable to workers of Callaway Golf Ball Operations, Inc., including on-site leased workers... are engaged in activities related to the production of golf balls. The notice was published in...

  9. Assuring reliability program effectiveness.

    NASA Technical Reports Server (NTRS)

    Ball, L. W.

    1973-01-01

    An attempt is made to provide simple identification and description of techniques that have proved to be most useful either in developing a new product or in improving reliability of an established product. The first reliability task is obtaining and organizing parts failure rate data. Other tasks are parts screening, tabulation of general failure rates, preventive maintenance, prediction of new product reliability, and statistical demonstration of achieved reliability. Five principal tasks for improving reliability involve the physics of failure research, derating of internal stresses, control of external stresses, functional redundancy, and failure effects control. A final task is the training and motivation of reliability specialist engineers.

  10. Study on the Interrater Reliability of an OSPE (Objective Structured Practical Examination) – Subject to the Evaluation Mode in the Phantom Course of Operative Dentistry

    PubMed Central

    Schmitt, Laura; Möltner, Andreas; Rüttermann, Stefan; Gerhardt-Szép, Susanne

    2016-01-01

    Introduction: The aim of the study presented here was to evaluate the reliability of an OSPE end-of-semester exam in the phantom course for operative dentistry in Frankfurt am Main taking into consideration different modes of evaluation (examiner’s checklist versus instructor’s manual) and number of examiners (three versus four). Methods: In an historic, monocentric, comparative study, two different methods of evaluation were examined in a real end-of-semester setting held in OSPE form (Group I: exclusive use of an examiner’s checklist versus Group II: use of an examiner’s checklist including an instructor’s manual). For the analysis of interrater reliability, the generalisability theory was applied that contains a generalisation of the concept of internal consistency (Cronbach’s alpha). Results: The results show that the exclusive use of the examiner’s checklist led to higher interrater reliability values than the in-depth instructor’s manual used in addition to the list. Conclusion: In summary it can be said that the examiner’s checklists used in the present study, without the instructor’s manual, resulted in the highest interrater reliability in combination with three evaluators within the context of the completed OSPE. PMID:27579361

  11. Strategies and Decision Support Systems for Integrating Variable Energy Resources in Control Centers for Reliable Grid Operations

    SciTech Connect

    Jones, Lawrence E.

    2011-11-01

    This report provides findings from the field regarding the best ways in which to guide operational strategies, business processes and control room tools to support the integration of renewable energy into electrical grids.

  12. Strategies and Decision Support Systems for Integrating Variable Energy Resources in Control Centers for Reliable Grid Operations. Executive Summary

    SciTech Connect

    Jones, Lawrence E.

    2011-11-01

    This is the executive summary for a report that provides findings from the field regarding the best ways in which to guide operational strategies, business processes and control room tools to support the integration of renewable energy into electrical grids.

  13. Investigation of the Long-Term Performance of the 324 MHz Klystrons for Achieving the Efficient Operation of the Linac at J-PARC

    NASA Astrophysics Data System (ADS)

    Hori, T.; Shinozaki, S.; Chishiro, E.; Sato, F.; Kawamura, M.; Futatsukawa, K.; Fukui, Y.; Oguri, H.

    As a part of the researches of the reliability and life time of klystrons, the cathode performance test of 324 MHz klystrons operated for 32000 hours on line has been performed at the klystron test stand. The experimental results coincide approximately with the data both reported in the literature for the cathode performance and the one obtained from the data base of RF data acquisition system. In this test, two parameters such as klystron beam perveance and knee-point were used to investigate the emission performance. It turned out that klystron beam perveance is most suitable parameter for understanding the klystron performance under operating condition on line.

  14. A CTE matched hard solder passively cooled laser diode package combined with nXLT facet passivation enables high power, high reliability operation

    NASA Astrophysics Data System (ADS)

    Hodges, Aaron; Wang, Jun; DeFranza, Mark; Liu, Xingsheng; Vivian, Bill; Johnson, Curt; Crump, Paul; Leisher, Paul; DeVito, Mark; Martinsen, Robert; Bell, Jacob

    2007-04-01

    A conductively cooled laser diode package design with hard AuSn solder and CTE matched sub mount is presented. We discuss how this platform eliminates the failure mechanisms associated with indium solder. We present the problem of catastrophic optical mirror damage (COMD) and show that nLight's nXLT TM facet passivation technology effectively eliminates facet defect initiated COMD as a failure mechanism for both single emitter and bar format laser diodes. By combining these technologies we have developed a product that has high reliability at high powers, even at increased operation temperatures. We present early results from on-going accelerated life testing of this configuration that suggests an 808nm, 30% fill factor device will have a MTTF of more than 21khrs at 60W CW, 25°C operating conditions and a MTTF of more than 6.4khrs when operated under hard pulsed (1 second on, 1 second off) conditions.

  15. Network reliability

    NASA Technical Reports Server (NTRS)

    Johnson, Marjory J.

    1985-01-01

    Network control (or network management) functions are essential for efficient and reliable operation of a network. Some control functions are currently included as part of the Open System Interconnection model. For local area networks, it is widely recognized that there is a need for additional control functions, including fault isolation functions, monitoring functions, and configuration functions. These functions can be implemented in either a central or distributed manner. The Fiber Distributed Data Interface Medium Access Control and Station Management protocols provide an example of distributed implementation. Relative information is presented here in outline form.

  16. Reliability of overbite depth indicator (ODI) and anteroposterior dysplasia indicator (APDI) in the assessment of different vertical and sagittal dental malocclusions: a receiver operating characteristic (ROC) analysis

    PubMed Central

    Fatima, Farheen; Fida, Mubassar; Shaikh, Attiya

    2016-01-01

    ABSTRACT Introduction: Differential diagnosis of skeletal and dental relationships is crucial for planning orthodontic treatment. Overbite depth indicator (ODI) and anteroposterior dysplasia indicator (APDI) had been introduced in the past for assessment of vertical and sagittal jaw relationships, respectively. Objective: The objectives of this study were to evaluate the reliability of ODI and APDI in overbite and Angle malocclusions, as well as assess their diagnostic reliability among males and females of different age groups. Material and Methods: This study was conducted using pretreatment dental casts and lateral cephalograms of 90 subjects. For ODI, subjects were divided into three groups based on overbite (normal overbite, open bite and deep bite). Likewise, the same subjects were divided for APDI into three groups, based on Angle's malocclusion classification (dental Class I, II and III malocclusions). Mann-Whitney U test was applied for comparison of study parameters regarding sex and different age groups. The mean values of ODI and APDI were compared among study groups by means of Kruskal-Wallis and post-hoc Dunnet T3 tests. The receiver operating characteristic (ROC) curve was applied to test diagnostic reliability. Results: Insignificant differences were found for ODI and APDI angles, particularly in regards to sex and age. Significant intergroup differences were found in different overbite groups and Angle's classification for ODI and APDI, respectively (p < 0.001). ROC showed 91% and 88% constancy with dental pattern in ODI and APDI, respectively. Conclusions: ODI can reliably differentiate deep bite versus normal overbite and deep bite versus open bite. APDI can reliably differentiate dental Class I, II and III malocclusions. PMID:27901232

  17. High-power operation of highly reliable narrow stripe pseudomorphic single quantum well lasers emitting at 980 nm

    NASA Technical Reports Server (NTRS)

    Larsson, A.; Forouhar, S.; Cody, J.; Lang, R. J.

    1990-01-01

    Ridge waveguide pseudomorphic InGaAs/GaAs/AlGaAs single-quantum-well lasers exhibiting record high quantum efficiencies and high output power densities (105 mW per facet from a 6 micron wide stripe) at a lasing wavelength of 980 nm are discussed that were fabricated from a graded index separate confinement heterostructure grown by molecular beam epitaxy. Life testing at an output power of 30 mW per uncoated facet reveals a slow gradual degradation during the initial 500 h of operation after which the operating characteristics of the lasers become stable. The emission wavelength, the high output power, and the fundamental lateral mode operation render these lasers suitable for pumping Er3+-doped fiber amplifiers.

  18. Can EGFR mutation status be reliably determined in pre-operative needle biopsies from adenocarcinomas of the lung?

    PubMed

    Lindahl, Kim Hein; Sørensen, Flemming Brandt; Jonstrup, Søren Peter; Olsen, Karen Ege; Loeschke, Siegfried

    2015-04-01

    The identification of EGFR mutations in non-small-cell lung cancer is important for selecting patients, who may benefit from treatment with EGFR tyrosine kinase inhibitors. The analysis is usually performed on cytological aspirates and/or histological needle biopsies, representing a small fraction of the tumour volume. The aim of the present investigation was to evaluate the diagnostic performance of this molecular test. We retrospectively included 201 patients with primary adenocarcinoma of the lung. EGFR mutation status (exon 19 deletions and exon 21 L858R point mutation) was evaluated on both pre-operative biopsies (131 histological and 70 cytological) and on the surgical specimens, using PCR. Samples with low tumour cell fraction were assigned to laser micro-dissection (LMD). We found nine (4.5%) patients with EGFR mutation in the lung tumour resections, but failed to identify mutation in one of the corresponding pre-operative, cytological specimens. Several (18.4%) analyses of the pre-operative biopsies were inconclusive, especially in case of biopsies undergoing LMD and regarding exon 21 analysis. Discrepancy of mutation status in one patient may reflect intra-tumoural heterogeneity or technical issues. Moreover, several inconclusive results in the diagnostic biopsies reveal that attention must be paid on the suitability of pre-operative biopsies for EGFR mutation analysis.

  19. Battery Energy Storage System battery durability and reliability under electric utility grid operations: Analysis of 3 years of real usage

    NASA Astrophysics Data System (ADS)

    Dubarry, Matthieu; Devie, Arnaud; Stein, Karl; Tun, Moe; Matsuura, Marc; Rocheleau, Richard

    2017-01-01

    Battery Energy Storage Systems (BESSs) show promise to help renewable energy sources integration onto the grid. These systems are expected to last for a decade or more, but the actual battery degradation under different real world conditions is still largely unknown. In this paper we analyze 3 years of usage of a lithium titanate BESS installed and in operation on an island power system in Hawai'i. The BESS was found to be operational 90% of the time and stored a cumulative 1.5 GWh of energy, which represents more than 5000 equivalent full cycles on the cells. This paper presents a statistical analysis of the BESS usage, develops a representative duty cycle, and provides an initial estimate of BESS degradation. The battery duty cycle was characterized based on 5 parameters: pulses duration, pulses intensity (current), SOC swing range, SOC event ramp rate, and temperature.

  20. Application of gasket performance data for design and operation of low emissions, high-reliability gasketed joints

    SciTech Connect

    Waterland, A.F. III

    1996-07-01

    The MTI project No. 47, Test Methods for Non-Asbestos Gasket Materials, opened everyone`s eyes to the breadth of performance and use information for gasket materials. What the MTI has started has resulted in a quiet revolution in gasketing, and just in time. Today`s emissions and reliability mandates have created a situation whereby gasket materials can no longer be selected and designed into systems simply through practicable experience and personnel judgment. A defined engineering approach is required. Based on the work initiated by the MTI and furthered by groups such as ASME and PVRC, there now exists extensive performance data for all gasketing materials. This presentation addresses the existence and usage of the various MTI and PVRC-type performance data as a tool for initial material selection. With this background, a novel simplification to the future ASME code procedure is introduced which allows for a simple yet accurate means of applying this widely available data to an emissions` control program at the plant level.

  1. Achieving Shared Situational Awareness During Steady-State Operations in New York State: A Model for Success

    DTIC Science & Technology

    2010-03-01

    organization and shared situational awareness 15 is sought between organizations and others. It is a metacognition of the operating environment that...understanding of a situation and perceives it, its history, and potential future(s), in the same way. It is a metacognition of the operating environment that...This assessment should culminate in the creation of a risk portfolio that includes a hierarchical prioritization of hazards, based upon their

  2. Window for Optimal Frequency Operation and Reliability of 3DEG and 2DEG Channels for Oxide Microwave MESFETs and HFETs

    DTIC Science & Technology

    2016-04-01

    Samples……………………………………………….…….9 Pulsed Measurement of Noise Temperature ………………10 Estimation of Background Temperature …………………..14 Hot-electron Energy...for pulsed hot-electron noise temperature measurement. Figure 4. Noise spectra under pulsed operation at different electric fields (stars stand for X...represents extrapolation, and the dotted lines are guides to the eye. [22] Figure 5. Time-dependent excess noise temperature measured during and after

  3. High Availability Applications for NOMADS at the NOAA Web Operations Center Aimed at Providing Reliable Real Time Access to Operational Model Data

    NASA Astrophysics Data System (ADS)

    Alpert, J. C.; Rutledge, G.; Wang, J.; Freeman, P.; Kang, C. Y.

    2009-05-01

    The NOAA Operational Modeling Archive Distribution System (NOMADS) is now delivering high availability services as part of NOAA's official real time data dissemination at its Web Operations Center (WOC). The WOC is a web service used by all organizational units in NOAA and acts as a data repository where public information can be posted to a secure and scalable content server. A goal is to foster collaborations among the research and education communities, value added retailers, and public access for science and development efforts aimed at advancing modeling and GEO-related tasks. The services used to access the operational model data output are the Open-source Project for a Network Data Access Protocol (OPeNDAP), implemented with the Grid Analysis and Display System (GrADS) Data Server (GDS), and applications for slicing, dicing and area sub-setting the large matrix of real time model data holdings. This approach insures an efficient use of computer resources because users transmit/receive only the data necessary for their tasks including metadata. Data sets served in this way with a high availability server offer vast possibilities for the creation of new products for value added retailers and the scientific community. New applications to access data and observations for verification of gridded model output, and progress toward integration with access to conventional and non-conventional observations will be discussed. We will demonstrate how users can use NOMADS services to repackage area subsets either using repackaging of GRIB2 files, or values selected by ensemble component, (forecast) time, vertical levels, global horizontal location, and by variable, virtually a 6- Dimensional analysis services across the internet.

  4. Systems reliability analysis for the national ignition facility

    SciTech Connect

    Majumdar, K.C.; Annese, C.E.; MacIntyre, A.T.; Sicherman, A.

    1996-06-12

    A Reliability, Availability and Maintainability (RAM) analysis was initiated for the National Ignition Facility (NIF). The NIF is an inertial confinement fusion research facility designed to achieve controlled thermonuclear reaction; the preferred site for the NIF is the Lawrence Livermore National Laboratory (LLNL). The NIF RAM analysis has three purposes: (1) to allocate top level reliability and availability goals for the systems, (2) to develop an operability model for optimum maintainability, and (3) to determine the achievability of the allocated goals of the RAM parameters for the NIF systems and the facility operation as a whole. An allocation model assigns the reliability and availability goals for front line and support systems by a top-down approach; reliability analysis uses a bottom-up approach to determine the system reliability and availability from component level to system level.

  5. European tendencies and co-operation in the field of ITS systems - national achievements and challenges in Hungary

    NASA Astrophysics Data System (ADS)

    Lindenbach, Ágnes

    2016-06-01

    The article presents the role of intelligent transport systems/services related to the implementation of the essential European and Hungarian transport policy objectives. The `ITS Directive' will provide a framework for the tasks/works to be performed in the forthcoming years within the priority areas of ITS. The European Commission published regulations / specifications for the priority actions in the form of delegated acts defining the tasks/responsibilities of Member States. Regional/European co-operation for Hungary started after the EU-accession of the country. Hungary was an active partner within the European CONNECT and EasyWay projects, currently Hungary is a member of the CROCODILE consortium.

  6. Reliability Analysis Model

    NASA Technical Reports Server (NTRS)

    1970-01-01

    RAM program determines probability of success for one or more given objectives in any complex system. Program includes failure mode and effects, criticality and reliability analyses, and some aspects of operations, safety, flight technology, systems design engineering, and configuration analyses.

  7. Estimating the Reliability of a Crewed Spacecraft

    NASA Astrophysics Data System (ADS)

    Lutomski, M. G.; Garza, J.

    2012-01-01

    Now that the Space Shuttle Program has been retired, the Russian Soyuz Launcher and Soyuz Spacecraft are the only means for crew transportation to and from the International Space Station (ISS). Are the astronauts and cosmonauts safer on the Soyuz than the Space Shuttle system? How do you estimate the reliability of such a crewed spacecraft? The recent loss of the 44 Progress resupply flight to the ISS has put these questions front and center. The Soyuz launcher has been in operation for over 40 years. There have been only two Loss of Crew (LOC) incidents and two Loss of Mission (LOM) incidents involving crew missions. Given that the most recent crewed Soyuz launcher incident took place in 1983, how do we determine current reliability of such a system? How do all of the failures of unmanned Soyuz family launchers such as the 44P impact the reliability of the currently operational crewed launcher? Does the Soyuz exhibit characteristics that demonstrate reliability growth and how would that be reflected in future estimates of success? In addition NASA has begun development of the Orion or Multi-Purpose Crewed Vehicle as well as started an initiative to purchase Commercial Crew services from private firms. The reliability targets are currently several times higher than the last Shuttle reliability estimate. Can these targets be compared to the reliability of the Soyuz arguably the highest reliable crewed spacecraft and launcher in the world to determine whether they are realistic and achievable? To help answer these questions this paper will explore how to estimate the reliability of the Soyuz launcher/spacecraft system over its mission to give a benchmark for other human spaceflight vehicles and their missions. Specifically this paper will look at estimating the Loss of Mission (LOM) and Loss of Crew (LOC) probability for an ISS crewed Soyuz launcher/spacecraft mission using historical data, reliability growth, and Probabilistic Risk Assessment (PRA) techniques.

  8. Optimizing results from pQCT: reliability of operator-dependent pQCT variables in cadavers and humans with low bone mass.

    PubMed

    Ashe, Maureen C; Liu-Ambrose, Teresa; Khan, Karim M; White, Neil; McKay, Heather A

    2005-01-01

    Peripheral quantitative computed tomography (pQCT) can assess bone geometric properties and separate cortical from trabecular bone. Despite pQCT's potential benefits for research, most reliability and accuracy studies have used a constant acquisition and analysis protocol. There are, however, numerous steps in the pQCT scan acquisition and analysis that are operator dependent. Whether or not these influence the quality of the pQCT scans and, potentially, the precision and validity of the data collected has been little explored. We investigated how pQCT outputs changed when operator-dependent parameters were varied, particularly when the bone of interest was of low mineral density. We found that bone parameters and scan failure rate varied significantly depending on the acquisition resolution; only one scan slice at the 10 and 30% radius is required to maintain adequate precision, and reference lines for sites should use a reproducible landmark. These results provide a foundation for recommending scan acquisition and analysis options for patients with low bone mass.

  9. Cw operation of the FMIT RFQ accelerator

    SciTech Connect

    Cornelius, W.D.

    1985-01-01

    Recently, we have achieved reliable cw operation of the Fusion Materials Irradiation Test (FMIT) radio-frequency quadrupole (RFQ) accelerator. In addition to the operational experiences in achieving this status, some of the modifications of the vacuum system, cooling system, and rf structure are discussed. Preliminary beam-characterization results are presented. 10 refs., 8 figs.

  10. Reliability assessment of GaAs- and InP-based diode lasers for high-energy single-pulse operation

    NASA Astrophysics Data System (ADS)

    Maiorov, M.; Damm, D.; Trofimov, I.; Zeidel, V.; Sellers, R.

    2009-08-01

    With the maturing of high-power diode laser technology, studies of laser-assisted ignition of a variety of substances are becoming an increasingly popular research topic. Its range of applications is wide - from fusing in the defense, construction and exploration industries to ignition in future combustion engines. Recent advances in InP-based technology have expanded the wavelength range that can be covered by multi-watt GaAs- and InP-based diode lasers to about 0.8 to 2 μm. With such a wide range, the wattage is no longer the sole defining factor for efficient ignition. Ignition-related studies should include the interaction of radiation of various wavelengths with matter and the reliability of devices based on different material systems. In this paper, we focus on the reliability of pulsed laser diodes for use in ignition applications. We discuss the existing data on the catastrophic optical damage (COD) of the mirrors of the GaAsbased laser diodes and come up with a non-destructive test method to predict the COD level of a particular device. This allows pre-characterization of the devices intended for fusing to eliminate failures during single-pulse operation in the field. We also tested InP-based devices and demonstrated that the maximum power is not limited by COD. Currently, devices with >10W output power are available from both GaAs- and InP-based devices, which dramatically expands the potential use of laser diodes in ignition systems.

  11. RFA-based 589-nm guide star lasers for ESO VLT: a paradigm shift in performance, operational simplicity, reliability, and maintenance

    NASA Astrophysics Data System (ADS)

    Friedenauer, Axel; Karpov, Vladimir; Wei, Daoping; Hager, Manfred; Ernstberger, Bernhard; Clements, Wallace R. L.; Kaenders, Wilhelm G.

    2012-07-01

    Large telescopes equipped with adaptive optics require 20-25W CW 589-nm sources with emission linewidths of ~5 MHz. These Guide Star (GS) lasers should also be highly reliable and simple to operate and maintain for many years at the top of a mountain facility. Under contract from ESO, industrial partners TOPTICA and MPBC are nearing completion of the development of GS lasers for the ESO VLT, with delivery of the first of four units scheduled for December 2012. We report on the design and performance of the fully-engineered Pre-Production Unit (PPU), including system reliability/availability analysis, the successfully-concluded qualification testing, long-term component and system level tests and long-term maintenance and support planning. The chosen approach is based on ESO's patented narrow-band Raman Fiber Amplifier (EFRA) technology. A master oscillator signal from a linearly-polarized TOPTICA 20-mW, 1178-nm CW diode laser, with stabilized emission frequency and controllable linewidth up to a few MHz, is amplified in an MPBC polarization-maintaining (PM) RFA pumped by a high-power 1120-nm PM fiber laser. With efficient stimulated Brillouin scattering suppression, an unprecedented 40W of narrow-band RFA output has been obtained. This is then mode-matched into a resonant-cavity doubler with a free-spectral-range matching the sodium D2a to D2b separation, allowing simultaneous generation of an additional frequency component (D2b line) to re-pump the sodium atom electronic population. With this technique, the return flux can be increased without having to resort to electro-optical modulators and without the risk of introducing optical wave front distortions. The demonstrated output powers with doubling efficiencies >80% at 589 nm easily exceed the 20W design goal and require less than 700 W of electrical power. In summary, the fiber-based guide star lasers provide excellent beam quality and are modular, turn-key, maintenance-free, reliable, efficient, and ruggedized

  12. General Aviation Aircraft Reliability Study

    NASA Technical Reports Server (NTRS)

    Pettit, Duane; Turnbull, Andrew; Roelant, Henk A. (Technical Monitor)

    2001-01-01

    This reliability study was performed in order to provide the aviation community with an estimate of Complex General Aviation (GA) Aircraft System reliability. To successfully improve the safety and reliability for the next generation of GA aircraft, a study of current GA aircraft attributes was prudent. This was accomplished by benchmarking the reliability of operational Complex GA Aircraft Systems. Specifically, Complex GA Aircraft System reliability was estimated using data obtained from the logbooks of a random sample of the Complex GA Aircraft population.

  13. Chapter 9: Reliability

    SciTech Connect

    Algora, Carlos; Espinet-Gonzalez, Pilar; Vazquez, Manuel; Bosco, Nick; Miller, David; Kurtz, Sarah; Rubio, Francisca; McConnell,Robert

    2016-04-15

    This chapter describes the accumulated knowledge on CPV reliability with its fundamentals and qualification. It explains the reliability of solar cells, modules (including optics) and plants. The chapter discusses the statistical distributions, namely exponential, normal and Weibull. The reliability of solar cells includes: namely the issues in accelerated aging tests in CPV solar cells, types of failure and failures in real time operation. The chapter explores the accelerated life tests, namely qualitative life tests (mainly HALT) and quantitative accelerated life tests (QALT). It examines other well proven and experienced PV cells and/or semiconductor devices, which share similar semiconductor materials, manufacturing techniques or operating conditions, namely, III-V space solar cells and light emitting diodes (LEDs). It addresses each of the identified reliability issues and presents the current state of the art knowledge for their testing and evaluation. Finally, the chapter summarizes the CPV qualification and reliability standards.

  14. Mission reliability model programmers guide

    NASA Astrophysics Data System (ADS)

    Medina, Joseph M.; Simonson, Jonathan H.; Veatch, Michael H.

    1986-12-01

    The Mission Reliability Model (MIREM) has been developed to evaluate the reliability and sustained operating capability of advanced electronic circuits during the early stages of development. MIREM is applicable to integrated systems that achieve fault tolerance through dynamic fault detection, fault isolation, and reconfiguration. The model can also be valuable in evaluating designs that employ only dedicated or hard-wired redundancy. The most unique feature of MIREM is its ability to accurately reflect the impact of reconfigurable, competing functions on system reliability. The user defines the resources necessary to support a required function, e.g., Global Positioning System (GPS), and the model will compute the probability of losing that functional capability over a certain operating time. A critical failure occurs when there is not a sufficient number of working resources to support a specified function. As an analytic model, MIREM determines a value for Mean Time Between Critical Failure, Mission Completion Success Probability, and Failure Resiliency. The MIREM Programmers Guide addresses the model's program structure, function of routines, interdependence of subprograms and common blocks, and file usage. The information needed to port the model to other computer systems is also provided.

  15. Unmanned Aerial Vehicle (UAV) Dynamic-Tracking Directional Wireless Antennas for Low Powered Applications that Require Reliable Extended Range Operations in Time Critical Scenarios

    SciTech Connect

    Scott G. Bauer; Matthew O. Anderson; James R. Hanneman

    2005-10-01

    The proven value of DOD Unmanned Aerial Vehicles (UAVs) will ultimately transition to National and Homeland Security missions that require real-time aerial surveillance, situation awareness, force protection, and sensor placement. Public services first responders who routinely risk personal safety to assess and report a situation for emergency actions will likely be the first to benefit from these new unmanned technologies. ‘Packable’ or ‘Portable’ small class UAVs will be particularly useful to the first responder. They require the least amount of training, no fixed infrastructure, and are capable of being launched and recovered from the point of emergency. All UAVs require wireless communication technologies for real- time applications. Typically on a small UAV, a low bandwidth telemetry link is required for command and control (C2), and systems health monitoring. If the UAV is equipped with a real-time Electro-Optical or Infrared (EO/Ir) video camera payload, a dedicated high bandwidth analog/digital link is usually required for reliable high-resolution imagery. In most cases, both the wireless telemetry and real-time video links will be integrated into the UAV with unity gain omni-directional antennas. With limited on-board power and payload capacity, a small UAV will be limited with the amount of radio-frequency (RF) energy it transmits to the users. Therefore, ‘packable’ and ‘portable’ UAVs will have limited useful operational ranges for first responders. This paper will discuss the limitations of small UAV wireless communications. The discussion will present an approach of utilizing a dynamic ground based real-time tracking high gain directional antenna to provide extend range stand-off operation, potential RF channel reuse, and assured telemetry and data communications from low-powered UAV deployed wireless assets.

  16. Operational research in primary health care planning: a theoretical model for estimating the coverage achieved by different distributions of staff and facilities

    PubMed Central

    Kemball-Cook, D.; Vaughan, J. P.

    1983-01-01

    This report outlines a basic operational research model for estimating the coverage achieved by different distributions of primary health care staff and facilities, using antenatal home visiting as an illustrative example. Coverage is estimated in terms of the average number of patient contacts achieved per annum. The model takes into account such features as number of facilities and health workers per 10 000 population, the radius of the health facility area, the overall population density in the region, the number of working days in the year, and the health worker's travelling time and work rate. A theoretical planning situation is also presented, showing the application of the model in defining various possible strategies, using certain planning norms for new levels of staff and facilities. This theoretical model is presented as an example of the use of operational research in primary health care, but it requires to be tested and validated in known situations before its usefulness can be assessed. Some indications are given of the ways in which the model could be adapted and improved for application to a real planning situation. PMID:6602666

  17. Operationally Efficient Propulsion System Study (OEPPS)

    NASA Technical Reports Server (NTRS)

    Wong, G. S.; Waldrop, G. S.; Byrd, R. J.; Ziese, J. M.

    1991-01-01

    A description is presented, through view graphs, of the problems encountered in today's launch vehicles and how these problems have adversely affected the ability to achieve serviceability, reliability, and operability. The need is emphasized to recognize and understand the operations problems and the effort that must be made to avoid them in future designs. Technology areas that will enhance operations requirements are also presented.

  18. Working Group summary reports from the Advanced Photon Source reliability workshop

    SciTech Connect

    Not Available

    1992-05-01

    A workshop was held at APS to address reliability goals for accelerator systems. Seventy-one individuals participated in the workshop, including 30 from other institutions. The goals of the workshop were to: (1) Give attendees an introduction to the basic concepts of reliability analysis. (2) Exchange information on operating experience at existing accelerator facilities and strategies for achieving reliability at facilities under design or in construction. (3) Discuss reliability goals for APS and the means of their achievement. This report contains the working group summary report an APS`s following systems: RF Systems; Power Supplies; Magnet Systems; Interlock and Diagnostics; and Vacuum Systems.

  19. Working Group summary reports from the Advanced Photon Source reliability workshop

    SciTech Connect

    Not Available

    1992-05-01

    A workshop was held at APS to address reliability goals for accelerator systems. Seventy-one individuals participated in the workshop, including 30 from other institutions. The goals of the workshop were to: (1) Give attendees an introduction to the basic concepts of reliability analysis. (2) Exchange information on operating experience at existing accelerator facilities and strategies for achieving reliability at facilities under design or in construction. (3) Discuss reliability goals for APS and the means of their achievement. This report contains the working group summary report an APS's following systems: RF Systems; Power Supplies; Magnet Systems; Interlock and Diagnostics; and Vacuum Systems.

  20. 76 FR 16277 - System Restoration Reliability Standards

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-03-23

    ... Energy Regulatory Commission 18 CFR Part 40 System Restoration Reliability Standards AGENCY: Federal... Act, the Commission approves three Emergency Operations and Preparedness (EOP) Reliability Standards... Resource'' submitted to the Commission for approval by the North American Electric Reliability...

  1. Operations

    ERIC Educational Resources Information Center

    Wilkins, Jesse L. M.; Norton, Anderson; Boyce, Steven J.

    2013-01-01

    Previous research has documented schemes and operations that undergird students' understanding of fractions. This prior research was based, in large part, on small-group teaching experiments. However, written assessments are needed in order for teachers and researchers to assess students' ways of operating on a whole-class scale. In this study,…

  2. Reliability and Maintainability Issues for the Next Linear Collider

    SciTech Connect

    Wilson, Zane J.; Gold, Saul L.; Koontz, Ron F.; Lavine, Ted L.; /SLAC

    2011-08-26

    Large accelerators for high energy physics research traditionally have been designed using informal best design, engineering, and management practices to achieve acceptable levels of operational availability. However, the Next Linear Collider(NLC) project presents a particular challenge for operational availability due to the unprecedented size and complexity of the accelerator systems required to achieve the physics goals of high center-of-mass energy and high luminosity. Formal reliability and maintainability analysis, design, and implementation will be required to achieve acceptable operational availability for the high energy physics research program. This paper introduces some of the basic concepts of reliability analysis and applies them to the 2.6-cm microwave power system of the two 10-km-long, 250-GeV linacs that are currently proposed for the NLC design.

  3. Reliability of the Planned Pedicle Screw Trajectory versus the Actual Pedicle Screw Trajectory using Intra-operative 3D CT and Image Guidance

    PubMed Central

    Ledonio, Charles G.; Hunt, Matthew A.; Siddiq, Farhan; Polly, David W.

    2016-01-01

    Background Technological advances, including navigation, have been made to improve safety and accuracy of pedicle screw fixation. We evaluated the accuracy of the virtual screw placement (Stealth projection) compared to actual screw placement (intra-operative O-Arm) and examined for differences based on the distance from the reference frame. Methods A retrospective evaluation of prospectively collected data was conducted from January 2013 to September 2013. We evaluated thoracic and lumbosacral pedicle screws placed using intraoperative O-arm and Stealth navigation by obtaining virtual screw projections and intraoperative O-arm images after screw placement. The screw trajectory angle to the midsagittal line and superior endplate was compared in the axial and sagittal views, respectively. Percent error and paired t-test statistics were then performed. Results Thirty-one patients with 240 pedicle screws were analyzed. The mean angular difference between the virtual and actual image in all screws was 2.17° ± 2.20° on axial images and 2.16° ± 2.24° on sagittal images. There was excellent agreement between actual and virtual pedicle screw trajectories in the axial and sagittal plane with ICC = 0.99 (95%CI: 0.992-0.995) (p<0.001) and ICC= 0.81 (95%CI: 0.759-0.855) (p<0.001) respectively. When comparing thoracic and lumbar screws, there was a significant difference in the sagittal angulation between the two distributions. No statistical differences were found distance from the reference frame. Conclusion The virtual projection view is clinically accurate compared to the actual placement on intra-operative CT in both the axial and sagittal views. There is slight imprecision (~2°) in the axial and sagittal planes and a minor difference in the sagittal thoracic and lumbar angulation, although these did not affect clinical outcomes. In general, we find that pedicle screw placement using intraoperative cone beam CT and navigation to be accurate and reliable, and as such

  4. Multiple-factor analysis of the first radioactive iodine therapy in post-operative patients with differentiated thyroid cancer for achieving a disease-free status

    PubMed Central

    Liu, Na; Meng, Zhaowei; Jia, Qiang; Tan, Jian; Zhang, Guizhi; Zheng, Wei; Wang, Renfei; Li, Xue; Hu, Tianpeng; Upadhyaya, Arun; Zhou, Pingping; Wang, Sen

    2016-01-01

    131I treatment is an important management method for patients with differentiated thyroid cancer (DTC). Unsuccessful 131I ablation drastically affects the prognosis of the patients. This study aimed to analyze potential predictive factors influencing the achievement of a disease-free status following the first 131I therapy. This retrospective review included 315 DTC patients, and multiple factors were analyzed. Tumor size, pathological tumor stage, lymph node (LN) metastasis, distant metastasis, American Thyroid Association recommended risks, pre-ablation thyroglobulin (Tg), and thyroid stimulating hormone (TSH) displayed significant differences between unsuccessful and successful group. Cutoff values of Tg and TSH to predict a successful outcome were 3.525 ng/mL and 99.700 uIU/ml by receiver operating characteristic curves analysis. Binary logistic regression analysis showed that tumor stage T3 or T4, LN metastasis to N1b station, intermediate and high risks, pre-ablation Tg ≥ 3.525 ng/ml and TSH <99.700 μIU/mL were significantly associated with unsuccessful outcomes. Logistic regression equation for achieving a disease-free status could be rendered as: y (successful treatment) = −0.270–0.503 X1 (LN metastasis) −0.236 X2 (Tg) + 0.015 X3 (TSH). This study demonstrated LN metastasis, pre-ablation Tg and TSH were the most powerful predictors for achieving a disease-free status by the first 131I therapy. PMID:27721492

  5. Person Reliability

    ERIC Educational Resources Information Center

    Lumsden, James

    1977-01-01

    Person changes can be of three kinds: developmental trends, swells, and tremors. Person unreliability in the tremor sense (momentary fluctuations) can be estimated from person characteristic curves. Average person reliability for groups can be compared from item characteristic curves. (Author)

  6. Kinematics of the upper cervical spine during high velocity-low amplitude manipulation. Analysis of intra- and inter-operator reliability for pre-manipulation positioning and impulse displacements.

    PubMed

    Dugailly, Pierre-Michel; Beyer, Benoît; Sobczak, Stéphane; Salvia, Patrick; Rooze, Marcel; Feipel, Véronique

    2014-10-01

    To date, kinematics data analyzing continuous 3D motion of upper cervical spine (UCS) manipulation is lacking. This in vitro study aims at investigating inter- and intra-operator reliability of kinematics during high velocity low amplitude manipulation of the UCS. Three fresh specimens were used. Restricted dissection was realized to attach technical clusters to each bone (skull to C2). Motion data was obtained using an optoelectronic system during manipulation. Kinematics data were integrated into specific-subject 3D models to provide anatomical motion representation during thrust manipulation. The reliability of manipulation kinematics was assessed for three practitioners performing two sessions of three repetitions on two separate days. For pre-manipulation positioning, average UCS ROM (SD) were 10° (5°), 22° (5°) and 14° (4°) for lateral bending, axial rotation and flexion-extension, respectively. For the impulse phase, average axial rotation magnitude ranged from 7° to 12°. Reliability analysis showed average RMS up to 8° for pre-manipulation positioning and up to 5° for the impulse phase. As compared to physiological ROM, this study supports the limited angular displacement during manipulation for UCS motion components, especially for axial rotation. Kinematics reliability confirms intra- and inter-operator consistency although pre-manipulation positioning reliability is slightly lower between practitioners and sessions.

  7. Reliability physics

    NASA Technical Reports Server (NTRS)

    Cuddihy, E. F.; Ross, R. G., Jr.

    1984-01-01

    Speakers whose topics relate to the reliability physics of solar arrays are listed and their topics briefly reviewed. Nine reports are reviewed ranging in subjects from studies of photothermal degradation in encapsulants and polymerizable ultraviolet stabilizers to interface bonding stability to electrochemical degradation of photovoltaic modules.

  8. Reliability Design Handbook

    DTIC Science & Technology

    1976-03-01

    prediction, failure modes and effects analysis ( FMEA ) and reliability growth techniques represent those prediction and design evaluation methods that...Assessment Production Operation Ö Maintenance MIL-HDBK- 217 Bayesian Techniques Probabilistic Design FMEA I R Growth " I...devices suffer thermal aging; oxidation and other chemical reactions are enhanced; viscosity reduction and evaporation of lubricants are problems

  9. Multidisciplinary System Reliability Analysis

    NASA Technical Reports Server (NTRS)

    Mahadevan, Sankaran; Han, Song; Chamis, Christos C. (Technical Monitor)

    2001-01-01

    The objective of this study is to develop a new methodology for estimating the reliability of engineering systems that encompass multiple disciplines. The methodology is formulated in the context of the NESSUS probabilistic structural analysis code, developed under the leadership of NASA Glenn Research Center. The NESSUS code has been successfully applied to the reliability estimation of a variety of structural engineering systems. This study examines whether the features of NESSUS could be used to investigate the reliability of systems in other disciplines such as heat transfer, fluid mechanics, electrical circuits etc., without considerable programming effort specific to each discipline. In this study, the mechanical equivalence between system behavior models in different disciplines are investigated to achieve this objective. A new methodology is presented for the analysis of heat transfer, fluid flow, and electrical circuit problems using the structural analysis routines within NESSUS, by utilizing the equivalence between the computational quantities in different disciplines. This technique is integrated with the fast probability integration and system reliability techniques within the NESSUS code, to successfully compute the system reliability of multidisciplinary systems. Traditional as well as progressive failure analysis methods for system reliability estimation are demonstrated, through a numerical example of a heat exchanger system involving failure modes in structural, heat transfer and fluid flow disciplines.

  10. Engineering measures to ensure reliable operation of the Tugur Tidal Power Station under the severe ice conditions of the Sea of Okhotsk

    SciTech Connect

    Karnovich, V.N.; Vasilevskii, A.G.; Tregub, G.A.; Shatalina, I.N.; Bernshtein, L.B.

    1994-06-01

    The complex energy situation in the Far East as a consequence of the impossibility of constructing reliable nuclear power stations at the given stage makes quite urgent the use of the energy of the tides occurring in the Tugur Bay of the Sea of Okhotsk.

  11. Stirling machine operating experience

    NASA Technical Reports Server (NTRS)

    Ross, Brad; Dudenhoefer, James E.

    1991-01-01

    Numerous Stirling machines have been built and operated, but the operating experience of these machines is not well known. It is important to examine this operating experience in detail, because it largely substantiates the claim that Stirling machines are capable of reliable and lengthy lives. The amount of data that exists is impressive, considering that many of the machines that have been built are developmental machines intended to show proof of concept, and were not expected to operate for any lengthy period of time. Some Stirling machines (typically free-piston machines) achieve long life through non-contact bearings, while other Stirling machines (typically kinematic) have achieved long operating lives through regular seal and bearing replacements. In addition to engine and system testing, life testing of critical components is also considered.

  12. Reliability Engineering Handbook

    DTIC Science & Technology

    1964-06-01

    INTEVAL 00 0 542 917 1953 OPERATING TIME IN HOURS Figure 6-4. TWT Reliability Function, Showing the 90% Confidence Interval 6-7 6-2-4 to 6-2-5 NAVWEPS...the lower one-sided 90% greater than 977 hours, or 90% confidence confidence limit on 0 is (.704)(530) = 373 that 0 lies between these two bounds . R...6-4 6-2-2 Measurement of Reliability (Application of Confidence Limits).. 6-4 6-2-3 Procedural Steps

  13. 75 FR 71625 - System Restoration Reliability Standards

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-11-24

    ... Energy Regulatory Commission 18 CFR Part 40 System Restoration Reliability Standards November 18, 2010... to approve Reliability Standards EOP-001-1 (Emergency Operations Planning), EOP- 005-2 (System... Commission by the North American Electric Reliability Corporation, the Electric Reliability Organization...

  14. Electrical insulation design requirements and reliability goals

    NASA Astrophysics Data System (ADS)

    Ross, R. G., Jr.

    1983-11-01

    The solar cells in a photovoltaic module which must be electrically isolated from module exterior surfaces to satisfy a variety of safety and operating considerations are discussed. The performance and reliability of the insulation system are examined. Technical requirements involve the capability of withstanding the differential voltage from the solar cells to the module frame. The maximum system voltage includes consideration of maximum open circuit array voltages achieved under low-temperature, high-irradiance conditions, and transient overvoltages due to system feedback of lightning transients. The latter is bounded by the characteristics of incorporated voltage limiting devices such as MOVs.

  15. Reliability Centered Maintenance - Methodologies

    NASA Technical Reports Server (NTRS)

    Kammerer, Catherine C.

    2009-01-01

    Journal article about Reliability Centered Maintenance (RCM) methodologies used by United Space Alliance, LLC (USA) in support of the Space Shuttle Program at Kennedy Space Center. The USA Reliability Centered Maintenance program differs from traditional RCM programs because various methodologies are utilized to take advantage of their respective strengths for each application. Based on operational experience, USA has customized the traditional RCM methodology into a streamlined lean logic path and has implemented the use of statistical tools to drive the process. USA RCM has integrated many of the L6S tools into both RCM methodologies. The tools utilized in the Measure, Analyze, and Improve phases of a Lean Six Sigma project lend themselves to application in the RCM process. All USA RCM methodologies meet the requirements defined in SAE JA 1011, Evaluation Criteria for Reliability-Centered Maintenance (RCM) Processes. The proposed article explores these methodologies.

  16. Computational methods for efficient structural reliability and reliability sensitivity analysis

    NASA Technical Reports Server (NTRS)

    Wu, Y.-T.

    1993-01-01

    This paper presents recent developments in efficient structural reliability analysis methods. The paper proposes an efficient, adaptive importance sampling (AIS) method that can be used to compute reliability and reliability sensitivities. The AIS approach uses a sampling density that is proportional to the joint PDF of the random variables. Starting from an initial approximate failure domain, sampling proceeds adaptively and incrementally with the goal of reaching a sampling domain that is slightly greater than the failure domain to minimize over-sampling in the safe region. Several reliability sensitivity coefficients are proposed that can be computed directly and easily from the above AIS-based failure points. These probability sensitivities can be used for identifying key random variables and for adjusting design to achieve reliability-based objectives. The proposed AIS methodology is demonstrated using a turbine blade reliability analysis problem.

  17. Reliability of large superconducting magnets through design

    NASA Astrophysics Data System (ADS)

    Henning, C. D.

    1980-09-01

    As superconducting magnet systems grow larger and become the central component of major systems involving fusion, magnetohydrodynamics, and high energy physics, their reliability must be commensurate with the enormous capital investment in the project. Creative design is the most effective way of ensuring magnet reliability and providing a reasonable limit on the amount of quality control needed. By subjecting the last drawing operation in superconductor manufacture to a stress larger than the magnet design stress, a 100 percent proof test is achieved; cabled conductors offer mechanical redundancy, as do some methods of conductor joining; ground plane insulation should be multilayered to prevent arcs, and interturn and interlayer insulation spaced to be compatible with the self-extinguishing of arcs during quench voltages; electrical leads should be thermally protected; and guard vacuum spaces can be incorporated to control helium leaks.

  18. Reliable avionics design for deep space

    NASA Astrophysics Data System (ADS)

    Johnson, Stephen B.

    The technical and organizational problems posed by the Space Exploration Initiative (SEI) are discussed, and some possible solutions are examined. It is pointed out that SEI poses a whole new set of challenging problems in the design of reliable systems. These missions and their corresponding systems are far more complex than current systems. The initiative requires a set of vehicles and systems which must have very high levels of autonomy, reliability, and operability for long periods of time. It is emphasized that to achieve these goals in the face of great complexity, new technologies and organizational techniques will be necessary. It is noted that the key to a good design is good people. Not only must good people be found, but they must be placed in positions appropriate to their skills. It is argued that the atomistic and autocratic paradigm of vertical organizations must be replaced with more team-oriented and democratic structures.

  19. Crystalline-silicon reliability lessons for thin-film modules

    NASA Technical Reports Server (NTRS)

    Ross, R. G., Jr.

    1985-01-01

    The reliability of crystalline silicon modules has been brought to a high level with lifetimes approaching 20 years, and excellent industry credibility and user satisfaction. The transition from crystalline modules to thin film modules is comparable to the transition from discrete transistors to integrated circuits. New cell materials and monolithic structures will require new device processing techniques, but the package function and design will evolve to a lesser extent. Although there will be new encapsulants optimized to take advantage of the mechanical flexibility and low temperature processing features of thin films, the reliability and life degradation stresses and mechanisms will remain mostly unchanged. Key reliability technologies in common between crystalline and thin film modules include hot spot heating, galvanic and electrochemical corrosion, hail impact stresses, glass breakage, mechanical fatigue, photothermal degradation of encapsulants, operating temperature, moisture sorption, circuit design strategies, product safety issues, and the process required to achieve a reliable product from a laboratory prototype.

  20. Reliability model of a monopropellant auxiliary propulsion system

    NASA Technical Reports Server (NTRS)

    Greenberg, J. S.

    1971-01-01

    A mathematical model and associated computer code has been developed which computes the reliability of a monopropellant blowdown hydrazine spacecraft auxiliary propulsion system as a function of time. The propulsion system is used to adjust or modify the spacecraft orbit over an extended period of time. The multiple orbit corrections are the multiple objectives which the auxiliary propulsion system is designed to achieve. Thus the reliability model computes the probability of successfully accomplishing each of the desired orbit corrections. To accomplish this, the reliability model interfaces with a computer code that models the performance of a blowdown (unregulated) monopropellant auxiliary propulsion system. The computer code acts as a performance model and as such gives an accurate time history of the system operating parameters. The basic timing and status information is passed on to and utilized by the reliability model which establishes the probability of successfully accomplishing the orbit corrections.

  1. Accelerator Availability and Reliability Issues

    SciTech Connect

    Steve Suhring

    2003-05-01

    Maintaining reliable machine operations for existing machines as well as planning for future machines' operability present significant challenges to those responsible for system performance and improvement. Changes to machine requirements and beam specifications often reduce overall machine availability in an effort to meet user needs. Accelerator reliability issues from around the world will be presented, followed by a discussion of the major factors influencing machine availability.

  2. Reliable broadcast protocols

    NASA Technical Reports Server (NTRS)

    Joseph, T. A.; Birman, Kenneth P.

    1989-01-01

    A number of broadcast protocols that are reliable subject to a variety of ordering and delivery guarantees are considered. Developing applications that are distributed over a number of sites and/or must tolerate the failures of some of them becomes a considerably simpler task when such protocols are available for communication. Without such protocols the kinds of distributed applications that can reasonably be built will have a very limited scope. As the trend towards distribution and decentralization continues, it will not be surprising if reliable broadcast protocols have the same role in distributed operating systems of the future that message passing mechanisms have in the operating systems of today. On the other hand, the problems of engineering such a system remain large. For example, deciding which protocol is the most appropriate to use in a certain situation or how to balance the latency-communication-storage costs is not an easy question.

  3. Reliability of sheet moulding composites (SMC) for the automotive industry

    NASA Astrophysics Data System (ADS)

    Lamanna, Giuseppe; Ceparano, Angelo; Sartore, Luciana

    2014-05-01

    The reliability of Sheet Moulding Composite (SMC) has been analysed by means of mechanical static and fatigue tests. SMCs showed substantial in-plane anisotropy either in terms of stiffness or strength reflecting the preferential orientation of the short fibres along the direction of the conveyor belt during the processing operations. The static data were modelled on a statistical basis assuming that the monotonic tensile strength follows a two-parameter Weibull distribution, while for the fatigue test we adopted a two parameters model already validated for Glass Fibre Reinforced Plastics (GFRP). Overall, the procedure indicated that he material reliability and its applicability limits can be achieved with a minimum of experimental tests.

  4. Ferrite logic reliability study

    NASA Technical Reports Server (NTRS)

    Baer, J. A.; Clark, C. B.

    1973-01-01

    Development and use of digital circuits called all-magnetic logic are reported. In these circuits the magnetic elements and their windings comprise the active circuit devices in the logic portion of a system. The ferrite logic device belongs to the all-magnetic class of logic circuits. The FLO device is novel in that it makes use of a dual or bimaterial ferrite composition in one physical ceramic body. This bimaterial feature, coupled with its potential for relatively high speed operation, makes it attractive for high reliability applications. (Maximum speed of operation approximately 50 kHz.)

  5. 20 000 h reliable operation of 100 µm stripe width 650 nm broad area lasers at more than 1.1 W output power

    NASA Astrophysics Data System (ADS)

    Sumpf, Bernd; Fricke, Jörg; Ressel, Peter; Zorn, Martin; Erbert, Götz; Tränkle, Günther

    2011-10-01

    Reliability tests for highly efficient high-power 650 nm broad area diode lasers will be presented. The devices have a 5 nm thick single GaInP quantum well as an active layer, which is embedded in AlGaInP waveguide layers and n-AlInP and p-AlGaAs cladding layers. The devices with a stripe width of 100 µm and a cavity length of 1.5 mm were soldered on diamond submounts and mounted on standard C-mounts for an efficient heat removal. The test was performed at a temperature of 15 °C over a first period of 10 000 h at 1.1 W followed by a second period of 10 000 h at 1.2 W. Based on the aging test and assuming a 60% confidence level, the lower limit of the mean time to failure of 87 000 h was determined for the devices.

  6. Virtually simulating the next generation of clean energy technologies: NETL's AVESTAR Center is dedicated to the safe, reliable and efficient operation of advanced energy plants with carbon capture

    SciTech Connect

    Zitney, S.

    2012-01-01

    Imagine using a real-time virtual simulator to learn to fly a space shuttle or rebuild your car's transmission without touching a piece of equipment or getting your hands dirty. Now, apply this concept to learning how to operate and control a state-of-the-art, electricity-producing power plant capable of carbon dioxide (CO{sub 2}) capture. That's what the National Energy Technology Laboratory's (NETL) Advanced Virtual Energy Simulation Training and Research (AVESTAR) Center (www.netl.doe.gov/avestar) is designed to do. Established as part of the Department of Energy's (DOE) initiative to advance new clean energy technology for power generation, the AVESTAR Center focuses primarily on providing simulation-based training for process engineers and energy plant operators, starting with the deployment of a first-of-a-kind operator training simulator for an integrated gasification combined cycle (IGCC) power plant with CO{sub 2} capture. The IGCC dynamic simulator builds on, and reaches beyond, conventional power plant simulators to merge, for the first time, a 'gasification with CO{sub 2} capture' process simulator with a 'combined-cycle' power simulator. Based on Invensys Operations Management's SimSci-Esscor DYNSIM software, the high-fidelity dynamic simulator provides realistic training on IGCC plant operations, including normal and faulted operations, as well as plant start-up, shutdown and power demand load changes. The highly flexible simulator also allows for testing of different types of fuel sources, such as petcoke and biomass, as well as co-firing fuel mixtures. The IGCC dynamic simulator is available at AVESTAR's two locations, NETL (Figure 1) and West Virginia University's National Research Center for Coal and Energy (www.nrcce.wvu.edu), both in Morgantown, W.Va. By offering a comprehensive IGCC training program, AVESTAR aims to develop a workforce well prepared to operate, control and manage commercial-scale gasification-based power plants with CO{sub 2

  7. High-Reliability Health Care: Getting There from Here

    PubMed Central

    Chassin, Mark R; Loeb, Jerod M

    2013-01-01

    Context Despite serious and widespread efforts to improve the quality of health care, many patients still suffer preventable harm every day. Hospitals find improvement difficult to sustain, and they suffer “project fatigue” because so many problems need attention. No hospitals or health systems have achieved consistent excellence throughout their institutions. High-reliability science is the study of organizations in industries like commercial aviation and nuclear power that operate under hazardous conditions while maintaining safety levels that are far better than those of health care. Adapting and applying the lessons of this science to health care offer the promise of enabling hospitals to reach levels of quality and safety that are comparable to those of the best high-reliability organizations. Methods We combined the Joint Commission's knowledge of health care organizations with knowledge from the published literature and from experts in high-reliability industries and leading safety scholars outside health care. We developed a conceptual and practical framework for assessing hospitals’ readiness for and progress toward high reliability. By iterative testing with hospital leaders, we refined the framework and, for each of its fourteen components, defined stages of maturity through which we believe hospitals must pass to reach high reliability. Findings We discovered that the ways that high-reliability organizations generate and maintain high levels of safety cannot be directly applied to today's hospitals. We defined a series of incremental changes that hospitals should undertake to progress toward high reliability. These changes involve the leadership's commitment to achieving zero patient harm, a fully functional culture of safety throughout the organization, and the widespread deployment of highly effective process improvement tools. Conclusions Hospitals can make substantial progress toward high reliability by undertaking several specific

  8. Improve filtration for optimum equipment reliability

    SciTech Connect

    Cervera, S.M.

    1996-01-01

    The introduction 20 years ago of the American Petroleum Institute Standard API-614 as a purchase specification for lubrication, shaft sealing and control oil systems, had a considerable impact and did much to improve system reliability at that time. Today, however, these recommendations regarding filter rating and flushing cleanliness are outdated. Much research in the tribology field correlates clearance size particulate contamination with accelerated component wear, fatigue and performance degradation. Some of these studies demonstrate that by decreasing the population of clearance size particulate in lubrication oils, component life increases exponentially. Knowing the dynamic clearances of a piece of machinery makes it possible, using the ISO 4406 Cleanliness Code, to determine what cleanliness level will minimize contamination-related component wear/fatigue and thus help optimize machinery performance and reliability. Data obtained by the author through random sampling of rotating equipment lube and seal oil systems indicate that the API-614 standard, as it pertains to filtration and flushing, is insufficient to ensure that particulate contamination is maintained to within the levels necessary to achieve optimum equipment reliability and safety, without increasing operating cost. Adopting and practicing the guidelines presented should result in the following benefits: (1) the frequency of bearing, oil pump, mechanical seal, fluid coupling, gearbox and hydraulic control valve failures would be minimized; (2) the mean time between planned maintenance (MTBPM) would be increased. The result will be a substantial increase in safety and cost savings to the operator.

  9. Reliability science and patient safety.

    PubMed

    Luria, Joseph W; Muething, Stephen E; Schoettker, Pamela J; Kotagal, Uma R

    2006-12-01

    Reliability is failure-free operation over time--the measurable capability of a process, procedure, or service to perform its intended function. Reliability science has the potential to help health care organizations reduce defects in care, increase the consistency with which care is delivered, and improve patient outcomes. Based on its principles, the Institute for Health care Improvement has developed a three-step model to prevent failures, mitigate the failures that occur, and redesign systems to reduce failures. Lessons may also be learned from complex organizations that have already adopted the principles of reliability science and operate with high rates of reliability. They share a preoccupation with failure, reluctance to simplify interpretations, sensitivity to operations, commitment to resilience, and underspecification of structures.

  10. Maintaining radiation exposures as low as reasonably achievable (ALARA) for dental personnel operating portable hand-held x-ray equipment.

    PubMed

    McGiff, Thomas J; Danforth, Robert A; Herschaft, Edward E

    2012-08-01

    Clinical experience indicates that newly available portable hand-held x-ray units provide advantages compared to traditional fixed properly installed and operated x-ray units in dental radiography. However, concern that hand-held x-ray units produce higher operator doses than fixed x-ray units has caused regulatory agencies to mandate requirements for use of hand-held units that go beyond those recommended by the manufacturer and can discourage the use of this technology. To assess the need for additional requirements, a hand-held x-ray unit and a pair of manikins were used to measure the dose to a simulated operator under two conditions: exposures made according to the manufacturer's recommendations and exposures made according to manufacturer's recommendation except for the removal of the x-ray unit's protective backscatter shield. Dose to the simulated operator was determined using an array of personal dosimeters and a pair of pressurized ion chambers. The results indicate that the dose to an operator of this equipment will be less than 0.6 mSv y⁻¹ if the device is used according to the manufacturer's recommendations. This suggests that doses to properly trained operators of well-designed, hand-held dental x-ray units will be below 1.0 mSv y⁻¹ (2% of the annual occupational dose limit) even if additional no additional operational requirements are established by regulatory agencies. This level of annual dose is similar to those reported as typical dental personnel using fixed x-ray units and appears to satisfy the ALARA principal for this class of occupational exposures.

  11. Comparison of reliability performance of group connected and conventional HVDC transmission systems

    SciTech Connect

    Kuruganty, S.

    1995-10-01

    A group connected HVDC transmission scheme is a variant of the unit connection where instead of a single generator, a group of generators are directly connected to the converter. Studies conducted in the past indicated that significant cost reduction can be achieved using this scheme. This is mainly due to the elimination of many components which results in considerable capital and operating cost savings to the utility. Concerns regarding the reliability performance of unit connected schemes were raised, however, there has not been a detailed reliability study conducted. This paper addresses the reliability evaluation aspect of a group connected scheme and compares the reliability performance of the group connected scheme with that of the conventional common collector system. Reliability models for both schemes were developed using a hypothetical system model based on the Nelson River system. Practical system component outage data was used to examine the reliability performance of both schemes.

  12. Recent advances in computational structural reliability analysis methods

    NASA Technical Reports Server (NTRS)

    Thacker, Ben H.; Wu, Y.-T.; Millwater, Harry R.; Torng, Tony Y.; Riha, David S.

    1993-01-01

    The goal of structural reliability analysis is to determine the probability that the structure will adequately perform its intended function when operating under the given environmental conditions. Thus, the notion of reliability admits the possibility of failure. Given the fact that many different modes of failure are usually possible, achievement of this goal is a formidable task, especially for large, complex structural systems. The traditional (deterministic) design methodology attempts to assure reliability by the application of safety factors and conservative assumptions. However, the safety factor approach lacks a quantitative basis in that the level of reliability is never known and usually results in overly conservative designs because of compounding conservatisms. Furthermore, problem parameters that control the reliability are not identified, nor their importance evaluated. A summary of recent advances in computational structural reliability assessment is presented. A significant level of activity in the research and development community was seen recently, much of which was directed towards the prediction of failure probabilities for single mode failures. The focus is to present some early results and demonstrations of advanced reliability methods applied to structural system problems. This includes structures that can fail as a result of multiple component failures (e.g., a redundant truss), or structural components that may fail due to multiple interacting failure modes (e.g., excessive deflection, resonate vibration, or creep rupture). From these results, some observations and recommendations are made with regard to future research needs.

  13. Reliable VLSI sequential controllers

    NASA Technical Reports Server (NTRS)

    Whitaker, S.; Maki, G.; Shamanna, M.

    1990-01-01

    A VLSI architecture for synchronous sequential controllers is presented that has attractive qualities for producing reliable circuits. In these circuits, one hardware implementation can realize any flow table with a maximum of 2(exp n) internal states and m inputs. Also all design equations are identical. A real time fault detection means is presented along with a strategy for verifying the correctness of the checking hardware. This self check feature can be employed with no increase in hardware. The architecture can be modified to achieve fail safe designs. With no increase in hardware, an adaptable circuit can be realized that allows replacement of faulty transitions with fault free transitions.

  14. Integrated modular engine - Reliability assessment

    NASA Astrophysics Data System (ADS)

    Parsley, R. C.; Ward, T. B.

    1992-07-01

    A major driver in the increased interest in integrated modular engine configurations is the desire for ultra reliability for future rocket propulsion systems. The concept of configuring multiple sets of turbomachinery networked to multiple thrust chamber assemblies has been identified as an approach with potential to achieve significant reliability enhancement. This paper summarizes the results of a reliability study comparing networked systems vs. discrete engine installations, both with and without major module and engine redundancy. The study was conducted for gas generator, expander, and staged combustion cycles. The results are representative of either booster or upper-stage applications and are indicative of either plug or nonplug installation philosophies.

  15. Load Control System Reliability

    SciTech Connect

    Trudnowski, Daniel

    2015-04-03

    This report summarizes the results of the Load Control System Reliability project (DOE Award DE-FC26-06NT42750). The original grant was awarded to Montana Tech April 2006. Follow-on DOE awards and expansions to the project scope occurred August 2007, January 2009, April 2011, and April 2013. In addition to the DOE monies, the project also consisted of matching funds from the states of Montana and Wyoming. Project participants included Montana Tech; the University of Wyoming; Montana State University; NorthWestern Energy, Inc., and MSE. Research focused on two areas: real-time power-system load control methodologies; and, power-system measurement-based stability-assessment operation and control tools. The majority of effort was focused on area 2. Results from the research includes: development of fundamental power-system dynamic concepts, control schemes, and signal-processing algorithms; many papers (including two prize papers) in leading journals and conferences and leadership of IEEE activities; one patent; participation in major actual-system testing in the western North American power system; prototype power-system operation and control software installed and tested at three major North American control centers; and, the incubation of a new commercial-grade operation and control software tool. Work under this grant certainly supported the DOE-OE goals in the area of “Real Time Grid Reliability Management.”

  16. Statistical modeling of software reliability

    NASA Technical Reports Server (NTRS)

    Miller, Douglas R.

    1992-01-01

    This working paper discusses the statistical simulation part of a controlled software development experiment being conducted under the direction of the System Validation Methods Branch, Information Systems Division, NASA Langley Research Center. The experiment uses guidance and control software (GCS) aboard a fictitious planetary landing spacecraft: real-time control software operating on a transient mission. Software execution is simulated to study the statistical aspects of reliability and other failure characteristics of the software during development, testing, and random usage. Quantification of software reliability is a major goal. Various reliability concepts are discussed. Experiments are described for performing simulations and collecting appropriate simulated software performance and failure data. This data is then used to make statistical inferences about the quality of the software development and verification processes as well as inferences about the reliability of software versions and reliability growth under random testing and debugging.

  17. Influence of shutdown phases on the microbial community composition and their effects on the operational reliability in a geothermal plant in the North German Basin

    NASA Astrophysics Data System (ADS)

    Westphal, Anke; Lerm, Stephanie; Miethling-Graff, Rona; Seibt, Andrea; Wolfgramm, Markus; Würdemann, Hilke

    2014-05-01

    Microbial activity can influence the dissolution and/or precipitation of minerals, as well as corrosion phenomena that may lead to a lower efficiency of engineered systems. To enhance the understanding of these processes, the microbial biocenosis in fluids produced from the cold well of a deep geothermal heat store located in the North German Basin (NGB) was characterized during normal plant operation and immediately after plant downtime phases. The microbial community composition was dominated by three different genera of sulphate reducing bacteria (SRB) and fermentative Halanaerobiaceae in the 46 ° C tempered fluids during regular operation, whereas after shut down phases sequences of sulphur oxidizing bacteria (SOB) were additionally detected. The detection of SOB is regarded as an indication of oxygen introduction into the well during the downtime phase. This corresponded to the higher redox potential of fluids taken directly after the restart of fluid production in the cold well. In addition to an extremely high particle loading rate after plant restart, a higher DNA content as well as an increase of specific gene copy numbers of SRB and SOB by a factor of 104 and 105 respectively were observed. Obviously stagnant conditions favored the enrichment of biomass and particles in the well. This is supported by the determination of a higher sulphate and hydrogen sulphide content in the fluids taken initially after plant restart. With increasing fluid production during the restart, SRB specific gene copy numbers decreased much slower than SOB specific gene copy numbers, which led to the assumption that SOB abundance is limited to the near wellbore area. Besides the absence of particle removal by fluid flow and the deposition of particles by sedimentation during the shut down phase, oxygen introduction and subsequent activity of SOB may also have favored microbial induced formation of precipitates in the well. It is quite likely that the interaction of SRB and SOB

  18. Reliability Growth Prediction

    DTIC Science & Technology

    1986-09-01

    the Duane model because: *e ’he reliability gSod’ data analyzed were reflective of a single Lesr- for • each equipment as opposed to a series of zest ...fabrication) and costs wbich are a function of test length (e.g., chamber operations). A life -cycle cost model, Ref. 14 for example, can be exercised tc...J. Gibson and K. K. Mcain APPROVED FOR FUBLIC RE1EAS NI ODSrRUTIG1,N UY-LUlHfF :-:-4 ROME AIR DEVELOPMENT CENTER Air Force Systems Command Griffiss

  19. Blade reliability collaborative :

    SciTech Connect

    Ashwill, Thomas D.; Ogilvie, Alistair B.; Paquette, Joshua A.

    2013-04-01

    The Blade Reliability Collaborative (BRC) was started by the Wind Energy Technologies Department of Sandia National Laboratories and DOE in 2010 with the goal of gaining insight into planned and unplanned O&M issues associated with wind turbine blades. A significant part of BRC is the Blade Defect, Damage and Repair Survey task, which will gather data from blade manufacturers, service companies, operators and prior studies to determine details about the largest sources of blade unreliability. This report summarizes the initial findings from this work.

  20. Developing and establishing the validity and reliability of the perceptions toward Aviation Safety Action Program (ASAP) and Line Operations Safety Audit (LOSA) questionnaires

    NASA Astrophysics Data System (ADS)

    Steckel, Richard J.

    Aviation Safety Action Program (ASAP) and Line Operations Safety Audits (LOSA) are voluntary safety reporting programs developed by the Federal Aviation Administration (FAA) to assist air carriers in discovering and fixing threats, errors and undesired aircraft states during normal flights that could result in a serious or fatal accident. These programs depend on voluntary participation of and reporting by air carrier pilots to be successful. The purpose of the study was to develop and validate a measurement scale to measure U.S. air carrier pilots' perceived benefits and/or barriers to participating in ASAP and LOSA programs. Data from these surveys could be used to make changes to or correct pilot misperceptions of these programs to improve participation and the flow of data. ASAP and LOSA a priori models were developed based on previous research in aviation and healthcare. Sixty thousand ASAP and LOSA paper surveys were sent to 60,000 current U.S. air carrier pilots selected at random from an FAA database of pilot certificates. Two thousand usable ASAP and 1,970 usable LOSA surveys were returned and analyzed using Confirmatory Factor Analysis. Analysis of the data using confirmatory actor analysis and model generation resulted in a five factor ASAP model (Ease of use, Value, Improve, Trust and Risk) and a five factor LOSA model (Value, Improve, Program Trust, Risk and Management Trust). ASAP and LOSA data were not normally distributed, so bootstrapping was used. While both final models exhibited acceptable fit with approximate fit indices, the exact fit hypothesis and the Bollen-Stine p value indicated possible model mis-specification for both ASAP and LOSA models.

  1. Stirling Convertor Fasteners Reliability Quantification

    NASA Technical Reports Server (NTRS)

    Shah, Ashwin R.; Korovaichuk, Igor; Kovacevich, Tiodor; Schreiber, Jeffrey G.

    2006-01-01

    Onboard Radioisotope Power Systems (RPS) being developed for NASA s deep-space science and exploration missions require reliable operation for up to 14 years and beyond. Stirling power conversion is a candidate for use in an RPS because it offers a multifold increase in the conversion efficiency of heat to electric power and reduced inventory of radioactive material. Structural fasteners are responsible to maintain structural integrity of the Stirling power convertor, which is critical to ensure reliable performance during the entire mission. Design of fasteners involve variables related to the fabrication, manufacturing, behavior of fasteners and joining parts material, structural geometry of the joining components, size and spacing of fasteners, mission loads, boundary conditions, etc. These variables have inherent uncertainties, which need to be accounted for in the reliability assessment. This paper describes these uncertainties along with a methodology to quantify the reliability, and provides results of the analysis in terms of quantified reliability and sensitivity of Stirling power conversion reliability to the design variables. Quantification of the reliability includes both structural and functional aspects of the joining components. Based on the results, the paper also describes guidelines to improve the reliability and verification testing.

  2. Reliability analysis framework for computer-assisted medical decision systems

    SciTech Connect

    Habas, Piotr A.; Zurada, Jacek M.; Elmaghraby, Adel S.; Tourassi, Georgia D.

    2007-02-15

    We present a technique that enhances computer-assisted decision (CAD) systems with the ability to assess the reliability of each individual decision they make. Reliability assessment is achieved by measuring the accuracy of a CAD system with known cases similar to the one in question. The proposed technique analyzes the feature space neighborhood of the query case to dynamically select an input-dependent set of known cases relevant to the query. This set is used to assess the local (query-specific) accuracy of the CAD system. The estimated local accuracy is utilized as a reliability measure of the CAD response to the query case. The underlying hypothesis of the study is that CAD decisions with higher reliability are more accurate. The above hypothesis was tested using a mammographic database of 1337 regions of interest (ROIs) with biopsy-proven ground truth (681 with masses, 656 with normal parenchyma). Three types of decision models, (i) a back-propagation neural network (BPNN), (ii) a generalized regression neural network (GRNN), and (iii) a support vector machine (SVM), were developed to detect masses based on eight morphological features automatically extracted from each ROI. The performance of all decision models was evaluated using the Receiver Operating Characteristic (ROC) analysis. The study showed that the proposed reliability measure is a strong predictor of the CAD system's case-specific accuracy. Specifically, the ROC area index for CAD predictions with high reliability was significantly better than for those with low reliability values. This result was consistent across all decision models investigated in the study. The proposed case-specific reliability analysis technique could be used to alert the CAD user when an opinion that is unlikely to be reliable is offered. The technique can be easily deployed in the clinical environment because it is applicable with a wide range of classifiers regardless of their structure and it requires neither additional

  3. LCOGT network observatory operations

    NASA Astrophysics Data System (ADS)

    Pickles, Andrew; Hjelstrom, Annie; Boroson, Todd; Burleson, Ben; Conway, Patrick; De Vera, Jon; Elphick, Mark; Haworth, Brian; Rosing, Wayne; Saunders, Eric; Thomas, Doug; White, Gary; Willis, Mark; Walker, Zach

    2014-08-01

    We describe the operational capabilities of the Las Cumbres Observatory Global Telescope Network. We summarize our hardware and software for maintaining and monitoring network health. We focus on methodologies to utilize the automated system to monitor availability of sites, instruments and telescopes, to monitor performance, permit automatic recovery, and provide automatic error reporting. The same jTCS control system is used on telescopes of apertures 0.4m, 0.8m, 1m and 2m, and for multiple instruments on each. We describe our network operational model, including workloads, and illustrate our current tools, and operational performance indicators, including telemetry and metrics reporting from on-site reductions. The system was conceived and designed to establish effective, reliable autonomous operations, with automatic monitoring and recovery - minimizing human intervention while maintaining quality. We illustrate how far we have been able to achieve that.

  4. How to Conduct Multimethod Field Studies in the Operating Room: The iPad Combined With a Survey App as a Valid and Reliable Data Collection Tool

    PubMed Central

    Tscholl, David W; Weiss, Mona; Spahn, Donat R

    2016-01-01

    Background Tablet computers such as the Apple iPad are progressively replacing traditional paper-and-pencil-based data collection. We combined the iPad with the ready-to-use survey software, iSurvey (from Harvestyourdata), to create a straightforward tool for data collection during the Anesthesia Pre-Induction Checklist (APIC) study, a hospital-wide multimethod intervention study involving observation of team performance and team member surveys in the operating room (OR). Objective We aimed to provide an analysis of the factors that led to the use of the iPad- and iSurvey-based tool for data collection, illustrate our experiences with the use of this data collection tool, and report the results of an expert survey about user experience with this tool. Methods We used an iPad- and iSurvey-based tool to observe anesthesia inductions conducted by 205 teams (N=557 team members) in the OR. In Phase 1, expert raters used the iPad- and iSurvey-based tool to rate team performance during anesthesia inductions, and anesthesia team members were asked to indicate their perceptions after the inductions. In Phase 2, we surveyed the expert raters about their perceptions regarding the use of the iPad- and iSurvey-based tool to observe, rate, and survey teams in the ORs. Results The results of Phase 1 showed that training data collectors on the iPad- and iSurvey-based data collection tool was effortless and there were no serious problems during data collection, upload, download, and export. Interrater agreement of the combined data collection tool was found to be very high for the team observations (median Fleiss’ kappa=0.88, 95% CI 0.78-1.00). The results of the follow-up expert rater survey (Phase 2) showed that the raters did not prefer a paper-and-pencil-based data collection method they had used during other earlier studies over the iPad- and iSurvey-based tool (median response 1, IQR 1-1; 1=do not agree, 2=somewhat disagree, 3=neutral, 4=somewhat agree, 5=fully agree). They

  5. Applicability and Limitations of Reliability Allocation Methods

    NASA Technical Reports Server (NTRS)

    Cruz, Jose A.

    2016-01-01

    Reliability allocation process may be described as the process of assigning reliability requirements to individual components within a system to attain the specified system reliability. For large systems, the allocation process is often performed at different stages of system design. The allocation process often begins at the conceptual stage. As the system design develops, more information about components and the operating environment becomes available, different allocation methods can be considered. Reliability allocation methods are usually divided into two categories: weighting factors and optimal reliability allocation. When properly applied, these methods can produce reasonable approximations. Reliability allocation techniques have limitations and implied assumptions that need to be understood by system engineers. Applying reliability allocation techniques without understanding their limitations and assumptions can produce unrealistic results. This report addresses weighting factors, optimal reliability allocation techniques, and identifies the applicability and limitations of each reliability allocation technique.

  6. Photovoltaic power system reliability considerations

    NASA Technical Reports Server (NTRS)

    Lalli, V. R.

    1980-01-01

    An example of how modern engineering and safety techniques can be used to assure the reliable and safe operation of photovoltaic power systems is presented. This particular application is for a solar cell power system demonstration project designed to provide electric power requirements for remote villages. The techniques utilized involve a definition of the power system natural and operating environment, use of design criteria and analysis techniques, an awareness of potential problems via the inherent reliability and FMEA methods, and use of fail-safe and planned spare parts engineering philosophy.

  7. Compact, Reliable EEPROM Controller

    NASA Technical Reports Server (NTRS)

    Katz, Richard; Kleyner, Igor

    2010-01-01

    A compact, reliable controller for an electrically erasable, programmable read-only memory (EEPROM) has been developed specifically for a space-flight application. The design may be adaptable to other applications in which there are requirements for reliability in general and, in particular, for prevention of inadvertent writing of data in EEPROM cells. Inadvertent writes pose risks of loss of reliability in the original space-flight application and could pose such risks in other applications. Prior EEPROM controllers are large and complex and do not provide all reasonable protections (in many cases, few or no protections) against inadvertent writes. In contrast, the present controller provides several layers of protection against inadvertent writes. The controller also incorporates a write-time monitor, enabling determination of trends in the performance of an EEPROM through all phases of testing. The controller has been designed as an integral subsystem of a system that includes not only the controller and the controlled EEPROM aboard a spacecraft but also computers in a ground control station, relatively simple onboard support circuitry, and an onboard communication subsystem that utilizes the MIL-STD-1553B protocol. (MIL-STD-1553B is a military standard that encompasses a method of communication and electrical-interface requirements for digital electronic subsystems connected to a data bus. MIL-STD- 1553B is commonly used in defense and space applications.) The intent was to both maximize reliability while minimizing the size and complexity of onboard circuitry. In operation, control of the EEPROM is effected via the ground computers, the MIL-STD-1553B communication subsystem, and the onboard support circuitry, all of which, in combination, provide the multiple layers of protection against inadvertent writes. There is no controller software, unlike in many prior EEPROM controllers; software can be a major contributor to unreliability, particularly in fault

  8. Reliability and Maintainability (RAM) Training

    NASA Technical Reports Server (NTRS)

    Lalli, Vincent R. (Editor); Malec, Henry A. (Editor); Packard, Michael H. (Editor)

    2000-01-01

    The theme of this manual is failure physics-the study of how products, hardware, software, and systems fail and what can be done about it. The intent is to impart useful information, to extend the limits of production capability, and to assist in achieving low-cost reliable products. In a broader sense the manual should do more. It should underscore the urgent need CI for mature attitudes toward reliability. Five of the chapters were originally presented as a classroom course to over 1000 Martin Marietta engineers and technicians. Another four chapters and three appendixes have been added, We begin with a view of reliability from the years 1940 to 2000. Chapter 2 starts the training material with a review of mathematics and a description of what elements contribute to product failures. The remaining chapters elucidate basic reliability theory and the disciplines that allow us to control and eliminate failures.

  9. Ultimately Reliable Pyrotechnic Systems

    NASA Technical Reports Server (NTRS)

    Scott, John H.; Hinkel, Todd

    2015-01-01

    This paper presents the methods by which NASA has designed, built, tested, and certified pyrotechnic devices for high reliability operation in extreme environments and illustrates the potential applications in the oil and gas industry. NASA's extremely successful application of pyrotechnics is built upon documented procedures and test methods that have been maintained and developed since the Apollo Program. Standards are managed and rigorously enforced for performance margins, redundancy, lot sampling, and personnel safety. The pyrotechnics utilized in spacecraft include such devices as small initiators and detonators with the power of a shotgun shell, detonating cord systems for explosive energy transfer across many feet, precision linear shaped charges for breaking structural membranes, and booster charges to actuate valves and pistons. NASA's pyrotechnics program is one of the more successful in the history of Human Spaceflight. No pyrotechnic device developed in accordance with NASA's Human Spaceflight standards has ever failed in flight use. NASA's pyrotechnic initiators work reliably in temperatures as low as -420 F. Each of the 135 Space Shuttle flights fired 102 of these initiators, some setting off multiple pyrotechnic devices, with never a failure. The recent landing on Mars of the Opportunity rover fired 174 of NASA's pyrotechnic initiators to complete the famous '7 minutes of terror.' Even after traveling through extreme radiation and thermal environments on the way to Mars, every one of them worked. These initiators have fired on the surface of Titan. NASA's design controls, procedures, and processes produce the most reliable pyrotechnics in the world. Application of pyrotechnics designed and procured in this manner could enable the energy industry's emergency equipment, such as shutoff valves and deep-sea blowout preventers, to be left in place for years in extreme environments and still be relied upon to function when needed, thus greatly enhancing

  10. Stirling machine operating experience

    SciTech Connect

    Ross, B.; Dudenhoefer, J.E.

    1994-09-01

    Numerous Stirling machines have been built and operated, but the operating experience of these machines is not well known. It is important to examine this operating experience in detail, because it largely substantiates the claim that stirling machines are capable of reliable and lengthy operating lives. The amount of data that exists is impressive, considering that many of the machines that have been built are developmental machines intended to show proof of concept, and are not expected to operate for lengthy periods of time. Some Stirling machines (typically free-piston machines) achieve long life through non-contact bearings, while other Stirling machines (typically kinematic) have achieved long operating lives through regular seal and bearing replacements. In addition to engine and system testing, life testing of critical components is also considered. The record in this paper is not complete, due to the reluctance of some organizations to release operational data and because several organizations were not contacted. The authors intend to repeat this assessment in three years, hoping for even greater participation.

  11. Operating Experience of the Tritium Laboratory at CRL

    SciTech Connect

    Gallagher, C.L.; McCrimmon, K.D.

    2005-07-15

    The Chalk River Laboratories Tritium Laboratory has been operating safely and reliably for over 20 years. Safe operations are achieved through proper management, supervision, training and using approved operating procedures and techniques. Reliability is achieved through appropriate equipment selection, routine equipment surveillance testing and routine preventative maintenance. This paper summarizes the laboratory's standard operating protocols and formal compliance programs followed to ensure safe operations. The paper will also review the general set-up of the laboratory and will focus on the experience gained with the operation of various types of equipment such as tritium monitors, tritium analyzers, pumps, purification systems and other systems used in the laboratory during its 20 years of operation.

  12. Reliability model generator

    NASA Technical Reports Server (NTRS)

    McMann, Catherine M. (Inventor); Cohen, Gerald C. (Inventor)

    1991-01-01

    An improved method and system for automatically generating reliability models for use with a reliability evaluation tool is described. The reliability model generator of the present invention includes means for storing a plurality of low level reliability models which represent the reliability characteristics for low level system components. In addition, the present invention includes means for defining the interconnection of the low level reliability models via a system architecture description. In accordance with the principles of the present invention, a reliability model for the entire system is automatically generated by aggregating the low level reliability models based on the system architecture description.

  13. Condensate polishers add operating reliability and flexibility

    SciTech Connect

    Layman, C.M.; Bennett, L.L.

    2008-08-15

    Many of today's advanced steam generators favour either an all-volatile treatment or oxygenated treatment chemistry programme, both of which require strict maintenance of an ultra-pure boiler fedwater ro condensate system. Those requirements are many times at odds with the lower-quality water sources, such as greywater, available for plant makeup and cooling water. Adding a condensate polisher can be a simple, cost-effective solution. 4 figs.

  14. RICOR's new development of a highly reliable integral rotary cooler: engineering and reliability aspects

    NASA Astrophysics Data System (ADS)

    Filis, Avishai; Pundak, Nachman; Barak, Moshe; Porat, Ze'ev; Jaeger, Mordechai

    2011-06-01

    The growing demand for EO applications that work around the clock 24hr/7days a week, such as in border surveillance systems, emphasizes the need for a highly reliable cryocooler having increased operational availability and decreased integrated system Life Cycle (ILS) cost. In order to meet this need RICOR has developed a new rotary Stirling cryocooler, model K508N, intended to double the K508's operating MTTF achieving 20,000 operating MTTF hours. The K508N employs RICOR's latest mechanical design technologies such as optimized bearings and greases, bearings preloading, advanced seals, laser welded cold finger and robust design structure with increased natural frequency compared to the K508 model. The cooler enhanced MTTF was demonstrated by a Validation and Verification (V&V) plan comprising analytical means and a comparative accelerated life test between the standard K508 and the K508N models. Particularly, point estimate and confidence interval for the MTTF improvement factor where calculated periodically during and after the test. The (V&V) effort revealed that the K508N meets its MTTF design goal. The paper will focus on the technical and engineering aspects of the new design. In addition it will discuss the market needs and expectations, investigate the reliability data of the present reference K508 model; and report the accelerate life test data and the statistical analysis methodology as well as its underlying assumptions and results.

  15. Interactive Maximum Reliability Cluster Analysis.

    ERIC Educational Resources Information Center

    Mays, Robert

    1978-01-01

    A FORTRAN program for clustering variables using the alpha coefficient of reliability is described. For batch operation, a rule for stopping the agglomerative precedure is available. The conversational version of the program allows the user to intervene in the process in order to test the final solution for sensitivity to changes. (Author/JKS)

  16. 76 FR 66055 - North American Electric Reliability Corporation; Order Approving Interpretation of Reliability...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-10-25

    ... the planning required to meet all System Operating Limits and Interconnection Reliability Operating...). Each Balancing Authority and Transmission Operator shall plan to meet all System Operating Limits (SOLs... under TOP-002-2a, Requirement R10 to ``plan to meet all System Operating Limits (SOLs)...

  17. Epistemological Beliefs and Academic Achievement

    ERIC Educational Resources Information Center

    Arslantas, Halis Adnan

    2016-01-01

    This study aimed to identify the relationship between teacher candidates' epistemological beliefs and academic achievement. The participants of the study were 353 teacher candidates studying their fourth year at the Education Faculty. The Epistemological Belief Scale was used which adapted to Turkish through reliability and validity work by…

  18. Reliability Generalization: "Lapsus Linguae"

    ERIC Educational Resources Information Center

    Smith, Julie M.

    2011-01-01

    This study examines the proposed Reliability Generalization (RG) method for studying reliability. RG employs the application of meta-analytic techniques similar to those used in validity generalization studies to examine reliability coefficients. This study explains why RG does not provide a proper research method for the study of reliability,…

  19. Can There Be Reliability without "Reliability?"

    ERIC Educational Resources Information Center

    Mislevy, Robert J.

    2004-01-01

    An "Educational Researcher" article by Pamela Moss (1994) asks the title question, "Can there be validity without reliability?" Yes, she answers, if by reliability one means "consistency among independent observations intended as interchangeable" (Moss, 1994, p. 7), quantified by internal consistency indices such as…

  20. Lessons from NASA. [spacecraft reliability engineering

    NASA Technical Reports Server (NTRS)

    Williams, W. C.

    1981-01-01

    Particular requirements related to the design and the operation of spacecraft have forced NASA to take a reliability approach that differs somewhat from that used in many other applications. NASA has found that some of the traditional tools of reliability engineering, such as life testing, reliability demonstration testing, maintainability analysis, and direct failure analysis, are impractical for spacecraft. In place of a statistical approach, the space agency uses an engineering approach to mission reliability. Reliability is to be obtained with the aid of three different approaches, including the application of effective design principles, the control and screening of all parts, and the testing of the entire spacecraft or its prototype for predicted capabilities. Attention is given to failure-mode analysis, the enhancement of Voyager reliability by autonomous operation, the redundancy in Shuttle design, the weeding out of bad hardware, and the preference for off-the-shelf devices.

  1. High reliability megawatt transformer/rectifier

    NASA Technical Reports Server (NTRS)

    Zwass, Samuel; Ashe, Harry; Peters, John W.

    1991-01-01

    The goal of the two phase program is to develop the technology and design and fabricate ultralightweight high reliability DC to DC converters for space power applications. The converters will operate from a 5000 V dc source and deliver 1 MW of power at 100 kV dc. The power weight density goal is 0.1 kg/kW. The cycle to cycle voltage stability goals was + or - 1 percent RMS. The converter is to operate at an ambient temperature of -40 C with 16 minute power pulses and one hour off time. The uniqueness of the design in Phase 1 resided in the dc switching array which operates the converter at 20 kHz using Hollotron plasma switches along with a specially designed low loss, low leakage inductance and a light weight high voltage transformer. This approach reduced considerably the number of components in the converter thereby increasing the system reliability. To achieve an optimum transformer for this application, the design uses four 25 kV secondary windings to produce the 100 kV dc output, thus reducing the transformer leakage inductance, and the ac voltage stresses. A specially designed insulation system improves the high voltage dielectric withstanding ability and reduces the insulation path thickness thereby reducing the component weight. Tradeoff studies and tests conducted on scaled-down model circuits and using representative coil insulation paths have verified the calculated transformer wave shape parameters and the insulation system safety. In Phase 1 of the program a converter design approach was developed and a preliminary transformer design was completed. A fault control circuit was designed and a thermal profile of the converter was also developed.

  2. Test effectiveness study report: An analytical study of system test effectiveness and reliability growth of three commercial spacecraft programs

    NASA Technical Reports Server (NTRS)

    Feldstein, J. F.

    1977-01-01

    Failure data from 16 commercial spacecraft were analyzed to evaluate failure trends, reliability growth, and effectiveness of tests. It was shown that the test programs were highly effective in ensuring a high level of in-orbit reliability. There was only a single catastrophic problem in 44 years of in-orbit operation on 12 spacecraft. The results also indicate that in-orbit failure rates are highly correlated with unit and systems test failure rates. The data suggest that test effectiveness estimates can be used to guide the content of a test program to ensure that in-orbit reliability goals are achieved.

  3. Asperger Syndrome and Academic Achievement.

    ERIC Educational Resources Information Center

    Griswold, Deborah E.; Barnhill, Gena P.; Myles, Brenda Smith; Hagiwara, Taku; Simpson, Richard L.

    2002-01-01

    A study focused on identifying the academic characteristics of 21 children and youth who have Asperger syndrome. Students had an extraordinary range of academic achievement scores, extending from significantly above average to far below grade level. Lowest achievement scores were shown for numerical operations, listening comprehension, and written…

  4. 78 FR 38851 - Electric Reliability Organization Proposal To Retire Requirements in Reliability Standards

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-06-28

    ... R5--Facility Ratings FAC-010-2.1, Requirement R5--System Operating Limits Methodology for the Planning Horizon FAC-011-2.1, Requirement R5--System Operating Limits Methodology for the Operations... system operating limits used in the reliable planning of the bulk electric system are determined based...

  5. Power electronics reliability analysis.

    SciTech Connect

    Smith, Mark A.; Atcitty, Stanley

    2009-12-01

    This report provides the DOE and industry with a general process for analyzing power electronics reliability. The analysis can help with understanding the main causes of failures, downtime, and cost and how to reduce them. One approach is to collect field maintenance data and use it directly to calculate reliability metrics related to each cause. Another approach is to model the functional structure of the equipment using a fault tree to derive system reliability from component reliability. Analysis of a fictitious device demonstrates the latter process. Optimization can use the resulting baseline model to decide how to improve reliability and/or lower costs. It is recommended that both electric utilities and equipment manufacturers make provisions to collect and share data in order to lay the groundwork for improving reliability into the future. Reliability analysis helps guide reliability improvements in hardware and software technology including condition monitoring and prognostics and health management.

  6. Human Reliability Program Overview

    SciTech Connect

    Bodin, Michael

    2012-09-25

    This presentation covers the high points of the Human Reliability Program, including certification/decertification, critical positions, due process, organizational structure, program components, personnel security, an overview of the US DOE reliability program, retirees and academia, and security program integration.

  7. The Advanced Communications Technology Satellite - Performance, Reliability and Lessons Learned

    NASA Technical Reports Server (NTRS)

    Krawczyk, Richard J.; Ignaczak, Louis R.

    2000-01-01

    The Advanced Communications Satellite (ACTS) was conceived and developed in the mid- 1980s as an experimental satellite to demonstrate unproven Ka-band technology, and potential new commercial applications and services. Since launch into geostationary orbit in September 1993. ACTS has accumulated almost seven years of essentially trouble-free operation and met all program objectives. The unique technology, service experiments. and system level demonstrations accomplished by ACTS have been reported in many forums over the past several years. As ACTS completes its final experiments activity, this paper will relate the top-level program goals that have been achieved in the design, operation, and performance of the particular satellite subsystems. Pre-launch decisions to ensure satellite reliability and the subsequent operational experiences contribute to lessons learned that may be applicable to other comsat programs.

  8. Highly reliable multisensor array (MSA) smart transducers

    NASA Astrophysics Data System (ADS)

    Perotti, José; Lucena, Angel; Mackey, Paul; Mata, Carlos; Immer, Christopher

    2006-05-01

    Many developments in the field of multisensor array (MSA) transducers have taken place in the last few years. Advancements in fabrication technology, such as Micro-Electro-Mechanical Systems (MEMS) and nanotechnology, have made implementation of MSA devices a reality. NASA Kennedy Space Center (KSC) has been developing this type of technology because of the increases in safety, reliability, and performance and the reduction in operational and maintenance costs that can be achieved with these devices. To demonstrate the MSA technology benefits, KSC quantified the relationship between the number of sensors (N) and the associated improvement in sensor life and reliability. A software algorithm was developed to monitor and assess the health of each element and the overall MSA. Furthermore, the software algorithm implemented criteria on how these elements would contribute to the MSA-calculated output to ensure required performance. The hypothesis was that a greater number of statistically independent sensor elements would provide a measurable increase in measurement reliability. A computer simulation was created to answer this question. An array of N sensors underwent random failures in the simulation and a life extension factor (LEF equals the percentage of the life of a single sensor) was calculated by the program. When LEF was plotted as a function of N, a quasiexponential behavior was detected with marginal improvement above N = 30. The hypothesis and follow-on simulation results were then corroborated experimentally. An array composed of eight independent pressure sensors was fabricated. To accelerate sensor life cycle and failure and to simulate degradation over time, the MSA was exposed to an environmental tem-perature of 125°C. Every 24 hours, the experiment's environmental temperature was returned to ambient temperature (27°C), and the outputs of all the MSA sensor elements were measured. Once per week, the MSA calibration was verified at five different

  9. Integrated avionics reliability

    NASA Technical Reports Server (NTRS)

    Alikiotis, Dimitri

    1988-01-01

    The integrated avionics reliability task is an effort to build credible reliability and/or performability models for multisensor integrated navigation and flight control. The research was initiated by the reliability analysis of a multisensor navigation system consisting of the Global Positioning System (GPS), the Long Range Navigation system (Loran C), and an inertial measurement unit (IMU). Markov reliability models were developed based on system failure rates and mission time.

  10. Reliable Design Versus Trust

    NASA Technical Reports Server (NTRS)

    Berg, Melanie; LaBel, Kenneth A.

    2016-01-01

    This presentation focuses on reliability and trust for the users portion of the FPGA design flow. It is assumed that the manufacturer prior to hand-off to the user tests FPGA internal components. The objective is to present the challenges of creating reliable and trusted designs. The following will be addressed: What makes a design vulnerable to functional flaws (reliability) or attackers (trust)? What are the challenges for verifying a reliable design versus a trusted design?

  11. Integrated Design Methodology for Highly Reliable Liquid Rocket Engine

    NASA Astrophysics Data System (ADS)

    Kuratani, Naoshi; Aoki, Hiroshi; Yasui, Masaaki; Kure, Hirotaka; Masuya, Goro

    The Integrated Design Methodology is strongly required at the conceptual design phase to achieve the highly reliable space transportation systems, especially the propulsion systems, not only in Japan but also all over the world in these days. Because in the past some catastrophic failures caused some losses of mission and vehicle (LOM/LOV) at the operational phase, moreover did affect severely the schedule delays and cost overrun at the later development phase. Design methodology for highly reliable liquid rocket engine is being preliminarily established and investigated in this study. The sensitivity analysis is systematically performed to demonstrate the effectiveness of this methodology, and to clarify and especially to focus on the correlation between the combustion chamber, turbopump and main valve as main components. This study describes the essential issues to understand the stated correlations, the need to apply this methodology to the remaining critical failure modes in the whole engine system, and the perspective on the engine development in the future.

  12. Estimating the Reliability of Electronic Parts in High Radiation Fields

    NASA Technical Reports Server (NTRS)

    Everline, Chester; Clark, Karla; Man, Guy; Rasmussen, Robert; Johnston, Allan; Kohlhase, Charles; Paulos, Todd

    2008-01-01

    Radiation effects on materials and electronic parts constrain the lifetime of flight systems visiting Europa. Understanding mission lifetime limits is critical to the design and planning of such a mission. Therefore, the operational aspects of radiation dose are a mission success issue. To predict and manage mission lifetime in a high radiation environment, system engineers need capable tools to trade radiation design choices against system design and reliability, and science achievements. Conventional tools and approaches provided past missions with conservative designs without the ability to predict their lifetime beyond the baseline mission.This paper describes a more systematic approach to understanding spacecraft design margin, allowing better prediction of spacecraft lifetime. This is possible because of newly available electronic parts radiation effects statistics and an enhanced spacecraft system reliability methodology. This new approach can be used in conjunction with traditional approaches for mission design. This paper describes the fundamentals of the new methodology.

  13. High reliability linear drive device for artificial hearts

    NASA Astrophysics Data System (ADS)

    Ji, Jinghua; Zhao, Wenxiang; Liu, Guohai; Shen, Yue; Wang, Fangqun

    2012-04-01

    In this paper, a new high reliability linear drive device, termed as stator-permanent-magnet tubular oscillating actuator (SPM-TOA), is proposed for artificial hearts (AHs). The key is to incorporate the concept of two independent phases into this linear AH device, hence achieving high reliability operation. The fault-tolerant teeth are employed to provide the desired decoupling phases in magnetic circuit. Also, as the magnets and the coils are located in the stator, the proposed SPM-TOA takes the definite advantages of robust mover and direct-drive capability. By using the time-stepping finite element method, the electromagnetic characteristics of the proposed SPM-TOA are analyzed, including magnetic field distributions, flux linkages, back- electromotive forces (back-EMFs) self- and mutual inductances, as well as cogging and thrust forces. The results confirm that the proposed SPM-TOA meets the dimension, weight, and force requirements of the AH drive device.

  14. Reliability Value of Fast State Estimation on Power Systems

    SciTech Connect

    Elizondo, Marcelo A.; Chen, Yousu; Huang, Zhenyu

    2012-05-07

    Monitoring the state of a power system under stress is key to achieving reliable operation. State estimation and timely measurements become more important when applying and designing corrective control actions (manual and automatic) to arrest or mitigate cascading blackouts. The execution time of each process, including state estimation, should be as short as possible to allow for timely action. In this paper, we provide a methodology for estimating one of the components of value of faster and more frequent state estimation: the reliability value of state estimation to assist corrective control actions for arresting or mitigating cascading blackouts. We present a new algorithm for estimating the time between successive line trips in a cascading failure. The algorithm combines power flow calculations with characteristics of the protection system to estimate the time between successive equipment trips. Using this algorithm, we illustrate the value of fast state estimation by calculating the time remaining for automatic or manual corrective actions after state estimation is finalized.

  15. Reliability and structural integrity

    NASA Technical Reports Server (NTRS)

    Davidson, J. R.

    1976-01-01

    An analytic model is developed to calculate the reliability of a structure after it is inspected for cracks. The model accounts for the growth of undiscovered cracks between inspections and their effect upon the reliability after subsequent inspections. The model is based upon a differential form of Bayes' Theorem for reliability, and upon fracture mechanics for crack growth.

  16. Reliability model generator specification

    NASA Technical Reports Server (NTRS)

    Cohen, Gerald C.; Mccann, Catherine

    1990-01-01

    The Reliability Model Generator (RMG), a program which produces reliability models from block diagrams for ASSIST, the interface for the reliability evaluation tool SURE is described. An account is given of motivation for RMG and the implemented algorithms are discussed. The appendices contain the algorithms and two detailed traces of examples.

  17. Viking Lander reliability program

    NASA Technical Reports Server (NTRS)

    Pilny, M. J.

    1978-01-01

    The Viking Lander reliability program is reviewed with attention given to the development of the reliability program requirements, reliability program management, documents evaluation, failure modes evaluation, production variation control, failure reporting and correction, and the parts program. Lander hardware failures which have occurred during the mission are listed.

  18. Theory of reliable systems

    NASA Technical Reports Server (NTRS)

    Meyer, J. F.

    1975-01-01

    An attempt was made to refine the current notion of system reliability by identifying and investigating attributes of a system which are important to reliability considerations. Techniques which facilitate analysis of system reliability are included. Special attention was given to fault tolerance, diagnosability, and reconfigurability characteristics of systems.

  19. Predicting software reliability

    NASA Technical Reports Server (NTRS)

    Littlewood, B.

    1989-01-01

    A detailed look is given to software reliability techniques. A conceptual model of the failure process is examined, and some software reliability growth models are discussed. Problems for which no current solutions exist are addressed, emphasizing the very difficult problem of safety-critical systems for which the reliability requirements can be enormously demanding.

  20. Creating Highly Reliable Accountable Care Organizations.

    PubMed

    Vogus, Timothy J; Singer, Sara J

    2016-12-01

    Accountable Care Organizations' (ACOs) pursuit of the triple aim of higher quality, lower cost, and improved population health has met with mixed results. To improve the design and implementation of ACOs we look to organizations that manage similarly complex, dynamic, and tightly coupled conditions while sustaining exceptional performance known as high-reliability organizations. We describe the key processes through which organizations achieve reliability, the leadership and organizational practices that enable it, and the role that professionals can play when charged with enacting it. Specifically, we present concrete practices and processes from health care organizations pursuing high-reliability and from early ACOs to illustrate how the triple aim may be met by cultivating mindful organizing, practicing reliability-enhancing leadership, and identifying and supporting reliability professionals. We conclude by proposing a set of research questions to advance the study of ACOs and high-reliability research.

  1. LAMPF reliability history and program

    SciTech Connect

    van Dyck, O.

    1994-09-01

    Many years of service of the 800-MeV LAMPF H{sup +}/H{sup {minus}} linac offers the opportunity to evaluate the long-term reliability characteristics of a high-power machine, which with up to 800-kW beam power available is as close to an ADTT machine as exists in the world today. Records from the last 15 years of operation were analyzed for trends and areas of deteriorating reliability or disproportionate downtime and used to support engineering judgment on facility refurbishment to regain beam availability. This round of analysis has helped define a further level of detail and automation to be implemented in availability recording. Interesting features which emerge from the history include a clear measurement of the lower availability in the first operating cycle following extended maintenance periods, and a consistent picture of the highest availability to be expected in extended operating periods with the facility as used and maintained. The results provide a starting point for informed discussion of reliability goals.

  2. Reliability Growth in Space Life Support Systems

    NASA Technical Reports Server (NTRS)

    Jones, Harry W.

    2014-01-01

    A hardware system's failure rate often increases over time due to wear and aging, but not always. Some systems instead show reliability growth, a decreasing failure rate with time, due to effective failure analysis and remedial hardware upgrades. Reliability grows when failure causes are removed by improved design. A mathematical reliability growth model allows the reliability growth rate to be computed from the failure data. The space shuttle was extensively maintained, refurbished, and upgraded after each flight and it experienced significant reliability growth during its operational life. In contrast, the International Space Station (ISS) is much more difficult to maintain and upgrade and its failure rate has been constant over time. The ISS Carbon Dioxide Removal Assembly (CDRA) reliability has slightly decreased. Failures on ISS and with the ISS CDRA continue to be a challenge.

  3. Human Reliability Analysis for Design: Using Reliability Methods for Human Factors Issues

    SciTech Connect

    Ronald Laurids Boring

    2010-11-01

    This paper reviews the application of human reliability analysis methods to human factors design issues. An application framework is sketched in which aspects of modeling typically found in human reliability analysis are used in a complementary fashion to the existing human factors phases of design and testing. The paper provides best achievable practices for design, testing, and modeling. Such best achievable practices may be used to evaluate and human system interface in the context of design safety certifications.

  4. Reliable, efficient systems for biomedical research facility

    SciTech Connect

    Basso, P.

    1997-05-01

    Medical Sciences Research Building III (MSRB III) is a 10-story, 207,000 ft{sup 2} (19,230 m{sup 2}) biomedical research facility on the campus of the University of Michigan. The design of MSRB III required a variety of technological solutions to complex design issues. The systems also had to accommodate future modifications. Closely integrated, modular systems with a high degree of flexibility were designed to respond to this requirement. Additionally, designs were kept as simple as possible for operation and maintenance personnel. Integrated electronic controls were used to provide vital data during troubleshooting and maintenance procedures. Equipment was also specified that provides reliability and minimizes maintenance. Other features include 100% redundancy of all central equipment servicing the animal housing area; redundant temperature controls for each individual animal housing room for fail-safe operation to protect the animals against overheating; and accessibility to all items requiring maintenance through an above-ceiling coordination process. It is critical that the engineering systems for MSRB III provide a safe, comfortable, energy efficient environment. The achievement of this design intent was noted by the University`s Commissioning Review Committee which stated: The Commissioning Process performed during both the design phase and construction phase of MSRB III was a significant success, providing an efficiently functioning facility that has been built in accordance with its design intent.

  5. Reliability assessment for components of large scale photovoltaic systems

    NASA Astrophysics Data System (ADS)

    Ahadi, Amir; Ghadimi, Noradin; Mirabbasi, Davar

    2014-10-01

    Photovoltaic (PV) systems have significantly shifted from independent power generation systems to a large-scale grid-connected generation systems in recent years. The power output of PV systems is affected by the reliability of various components in the system. This study proposes an analytical approach to evaluate the reliability of large-scale, grid-connected PV systems. The fault tree method with an exponential probability distribution function is used to analyze the components of large-scale PV systems. The system is considered in the various sequential and parallel fault combinations in order to find all realistic ways in which the top or undesired events can occur. Additionally, it can identify areas that the planned maintenance should focus on. By monitoring the critical components of a PV system, it is possible not only to improve the reliability of the system, but also to optimize the maintenance costs. The latter is achieved by informing the operators about the system component's status. This approach can be used to ensure secure operation of the system by its flexibility in monitoring system applications. The implementation demonstrates that the proposed method is effective and efficient and can conveniently incorporate more system maintenance plans and diagnostic strategies.

  6. Reliability and availability studies in the RIA driver linac.

    SciTech Connect

    Lessner, E. S.; Ostroumov, P. N.; Physics

    2005-01-01

    The Rare Isotope Accelerator (RIA) facility will include various complex systems and must provide radioactive beams to many users simultaneously. The availability of radioactive beams for most experiments at the fully-commissioned facility should be as high as possible within design cost limitations. To make a realistic estimate of the achievable reliability a detailed analysis is required. The RIA driver linac is a complex machine containing a large number of superconducting (SC) resonators and capable of accelerating multiple-charge-state beams [1]. At the pre-CDR stage of the design it is essential to identify critical facility subsystem failures that can prevent the driver linac from operating. The reliability and availability of the driver linac were studied using expert information and data from operating machines such as ATLAS, APS, JLab, and LANL. Availability studies are performed with a Monte-Carlo simulation code previously applied to availability assessments of the NLC facility [2] and the results used to identify subsystem failures that most affect the availability and reliability of the RIA driver, and guide design iterations and component specifications to address identified problems.

  7. Designing magnetic systems for reliability

    SciTech Connect

    Heitzenroeder, P.J.

    1991-01-01

    Designing magnetic system is an iterative process in which the requirements are set, a design is developed, materials and manufacturing processes are defined, interrelationships with the various elements of the system are established, engineering analyses are performed, and fault modes and effects are studied. Reliability requires that all elements of the design process, from the seemingly most straightforward such as utilities connection design and implementation, to the most sophisticated such as advanced finite element analyses, receives a balanced and appropriate level of attention. D.B. Montgomery's study of magnet failures has shown that the predominance of magnet failures tend not to be in the most intensively engineered areas, but are associated with insulation, leads, ad unanticipated conditions. TFTR, JET, JT-60, and PBX are all major tokamaks which have suffered loss of reliability due to water leaks. Similarly the majority of causes of loss of magnet reliability at PPPL has not been in the sophisticated areas of the design but are due to difficulties associated with coolant connections, bus connections, and external structural connections. Looking towards the future, the major next-devices such as BPX and ITER are most costly and complex than any of their predecessors and are pressing the bounds of operating levels, materials, and fabrication. Emphasis on reliability is a must as the fusion program enters a phase where there are fewer, but very costly devices with the goal of reaching a reactor prototype stage in the next two or three decades. This paper reviews some of the magnet reliability issues which PPPL has faced over the years the lessons learned from them, and magnet design and fabrication practices which have been found to contribute to magnet reliability.

  8. Six Motivational Reasons for Low School Achievement

    ERIC Educational Resources Information Center

    Reiss, Steven

    2009-01-01

    Reiss ("The normal personality: a new way of thinking about people." Cambridge University Press, New York, 2008) empirically derived a reliable and valid taxonomy of 16 life motives ("psychological needs"). The model suggests six motivational reasons for low achievement in school. Low achievement may be motivated by fear of failure (high need for…

  9. Software Reliability 2002

    NASA Technical Reports Server (NTRS)

    Wallace, Dolores R.

    2003-01-01

    In FY01 we learned that hardware reliability models need substantial changes to account for differences in software, thus making software reliability measurements more effective, accurate, and easier to apply. These reliability models are generally based on familiar distributions or parametric methods. An obvious question is 'What new statistical and probability models can be developed using non-parametric and distribution-free methods instead of the traditional parametric method?" Two approaches to software reliability engineering appear somewhat promising. The first study, begin in FY01, is based in hardware reliability, a very well established science that has many aspects that can be applied to software. This research effort has investigated mathematical aspects of hardware reliability and has identified those applicable to software. Currently the research effort is applying and testing these approaches to software reliability measurement, These parametric models require much project data that may be difficult to apply and interpret. Projects at GSFC are often complex in both technology and schedules. Assessing and estimating reliability of the final system is extremely difficult when various subsystems are tested and completed long before others. Parametric and distribution free techniques may offer a new and accurate way of modeling failure time and other project data to provide earlier and more accurate estimates of system reliability.

  10. Recalibrating software reliability models

    NASA Technical Reports Server (NTRS)

    Brocklehurst, Sarah; Chan, P. Y.; Littlewood, Bev; Snell, John

    1990-01-01

    In spite of much research effort, there is no universally applicable software reliability growth model which can be trusted to give accurate predictions of reliability in all circumstances. Further, it is not even possible to decide a priori which of the many models is most suitable in a particular context. In an attempt to resolve this problem, techniques were developed whereby, for each program, the accuracy of various models can be analyzed. A user is thus enabled to select that model which is giving the most accurate reliability predicitons for the particular program under examination. One of these ways of analyzing predictive accuracy, called the u-plot, in fact allows a user to estimate the relationship between the predicted reliability and the true reliability. It is shown how this can be used to improve reliability predictions in a completely general way by a process of recalibration. Simulation results show that the technique gives improved reliability predictions in a large proportion of cases. However, a user does not need to trust the efficacy of recalibration, since the new reliability estimates prodcued by the technique are truly predictive and so their accuracy in a particular application can be judged using the earlier methods. The generality of this approach would therefore suggest that it be applied as a matter of course whenever a software reliability model is used.

  11. Recalibrating software reliability models

    NASA Technical Reports Server (NTRS)

    Brocklehurst, Sarah; Chan, P. Y.; Littlewood, Bev; Snell, John

    1989-01-01

    In spite of much research effort, there is no universally applicable software reliability growth model which can be trusted to give accurate predictions of reliability in all circumstances. Further, it is not even possible to decide a priori which of the many models is most suitable in a particular context. In an attempt to resolve this problem, techniques were developed whereby, for each program, the accuracy of various models can be analyzed. A user is thus enabled to select that model which is giving the most accurate reliability predictions for the particular program under examination. One of these ways of analyzing predictive accuracy, called the u-plot, in fact allows a user to estimate the relationship between the predicted reliability and the true reliability. It is shown how this can be used to improve reliability predictions in a completely general way by a process of recalibration. Simulation results show that the technique gives improved reliability predictions in a large proportion of cases. However, a user does not need to trust the efficacy of recalibration, since the new reliability estimates produced by the technique are truly predictive and so their accuracy in a particular application can be judged using the earlier methods. The generality of this approach would therefore suggest that it be applied as a matter of course whenever a software reliability model is used.

  12. Key Reliability Drivers of Liquid Propulsion Engines and A Reliability Model for Sensitivity Analysis

    NASA Technical Reports Server (NTRS)

    Huang, Zhao-Feng; Fint, Jeffry A.; Kuck, Frederick M.

    2005-01-01

    This paper is to address the in-flight reliability of a liquid propulsion engine system for a launch vehicle. We first establish a comprehensive list of system and sub-system reliability drivers for any liquid propulsion engine system. We then build a reliability model to parametrically analyze the impact of some reliability parameters. We present sensitivity analysis results for a selected subset of the key reliability drivers using the model. Reliability drivers identified include: number of engines for the liquid propulsion stage, single engine total reliability, engine operation duration, engine thrust size, reusability, engine de-rating or up-rating, engine-out design (including engine-out switching reliability, catastrophic fraction, preventable failure fraction, unnecessary shutdown fraction), propellant specific hazards, engine start and cutoff transient hazards, engine combustion cycles, vehicle and engine interface and interaction hazards, engine health management system, engine modification, engine ground start hold down with launch commit criteria, engine altitude start (1 in. start), Multiple altitude restart (less than 1 restart), component, subsystem and system design, manufacturing/ground operation support/pre and post flight check outs and inspection, extensiveness of the development program. We present some sensitivity analysis results for the following subset of the drivers: number of engines for the propulsion stage, single engine total reliability, engine operation duration, engine de-rating or up-rating requirements, engine-out design, catastrophic fraction, preventable failure fraction, unnecessary shutdown fraction, and engine health management system implementation (basic redlines and more advanced health management systems).

  13. Graded Achievement, Tested Achievement, and Validity

    ERIC Educational Resources Information Center

    Brookhart, Susan M.

    2015-01-01

    Twenty-eight studies of grades, over a century, were reviewed using the argument-based approach to validity suggested by Kane as a theoretical framework. The review draws conclusions about the meaning of graded achievement, its relation to tested achievement, and changes in the construct of graded achievement over time. "Graded…

  14. Reliability based design optimization: Formulations and methodologies

    NASA Astrophysics Data System (ADS)

    Agarwal, Harish

    Modern products ranging from simple components to complex systems should be designed to be optimal and reliable. The challenge of modern engineering is to ensure that manufacturing costs are reduced and design cycle times are minimized while achieving requirements for performance and reliability. If the market for the product is competitive, improved quality and reliability can generate very strong competitive advantages. Simulation based design plays an important role in designing almost any kind of automotive, aerospace, and consumer products under these competitive conditions. Single discipline simulations used for analysis are being coupled together to create complex coupled simulation tools. This investigation focuses on the development of efficient and robust methodologies for reliability based design optimization in a simulation based design environment. Original contributions of this research are the development of a novel efficient and robust unilevel methodology for reliability based design optimization, the development of an innovative decoupled reliability based design optimization methodology, the application of homotopy techniques in unilevel reliability based design optimization methodology, and the development of a new framework for reliability based design optimization under epistemic uncertainty. The unilevel methodology for reliability based design optimization is shown to be mathematically equivalent to the traditional nested formulation. Numerical test problems show that the unilevel methodology can reduce computational cost by at least 50% as compared to the nested approach. The decoupled reliability based design optimization methodology is an approximate technique to obtain consistent reliable designs at lesser computational expense. Test problems show that the methodology is computationally efficient compared to the nested approach. A framework for performing reliability based design optimization under epistemic uncertainty is also developed

  15. A highly reliable LAN protocol

    NASA Astrophysics Data System (ADS)

    Weaver, A. C.

    1986-10-01

    As a research project for NASA's Langley Research Center, a variation on the military standard for avionics buses was developed to increase fault tolerance. The resulting protocol, called implicit token passing (ITP), replaces an explicit token with brief 'soundoff' messages from all nodes participating on the LAN. ITP features high throughput and bounded message delay, and achieves high reliability through tolerance of failed nodes and automatic resynchronization when failed nodes are revived. The protocol is ideally suited for a bus topology and fiber optic media.

  16. Reliability, Recursion, and Risk.

    ERIC Educational Resources Information Center

    Henriksen, Melvin, Ed.; Wagon, Stan, Ed.

    1991-01-01

    The discrete mathematics topics of trees and computational complexity are implemented in a simple reliability program which illustrates the process advantages of the PASCAL programing language. The discussion focuses on the impact that reliability research can provide in assessment of the risks found in complex technological ventures. (Author/JJK)

  17. Monte Carlo Reliability Analysis.

    DTIC Science & Technology

    1987-10-01

    to Stochastic Processes , Prentice-Hall, Englewood Cliffs, NJ, 1975. (5) R. E. Barlow and F. Proscham, Statistical TheorX of Reliability and Life...Lewis and Z. Tu, "Monte Carlo Reliability Modeling by Inhomogeneous ,Markov Processes, Reliab. Engr. 16, 277-296 (1986). (4) E. Cinlar, Introduction

  18. Hawaii electric system reliability.

    SciTech Connect

    Silva Monroy, Cesar Augusto; Loose, Verne William

    2012-09-01

    This report addresses Hawaii electric system reliability issues; greater emphasis is placed on short-term reliability but resource adequacy is reviewed in reference to electric consumers' views of reliability %E2%80%9Cworth%E2%80%9D and the reserve capacity required to deliver that value. The report begins with a description of the Hawaii electric system to the extent permitted by publicly available data. Electrical engineering literature in the area of electric reliability is researched and briefly reviewed. North American Electric Reliability Corporation standards and measures for generation and transmission are reviewed and identified as to their appropriateness for various portions of the electric grid and for application in Hawaii. Analysis of frequency data supplied by the State of Hawaii Public Utilities Commission is presented together with comparison and contrast of performance of each of the systems for two years, 2010 and 2011. Literature tracing the development of reliability economics is reviewed and referenced. A method is explained for integrating system cost with outage cost to determine the optimal resource adequacy given customers' views of the value contributed by reliable electric supply. The report concludes with findings and recommendations for reliability in the State of Hawaii.

  19. Hawaii Electric System Reliability

    SciTech Connect

    Loose, Verne William; Silva Monroy, Cesar Augusto

    2012-08-01

    This report addresses Hawaii electric system reliability issues; greater emphasis is placed on short-term reliability but resource adequacy is reviewed in reference to electric consumers’ views of reliability “worth” and the reserve capacity required to deliver that value. The report begins with a description of the Hawaii electric system to the extent permitted by publicly available data. Electrical engineering literature in the area of electric reliability is researched and briefly reviewed. North American Electric Reliability Corporation standards and measures for generation and transmission are reviewed and identified as to their appropriateness for various portions of the electric grid and for application in Hawaii. Analysis of frequency data supplied by the State of Hawaii Public Utilities Commission is presented together with comparison and contrast of performance of each of the systems for two years, 2010 and 2011. Literature tracing the development of reliability economics is reviewed and referenced. A method is explained for integrating system cost with outage cost to determine the optimal resource adequacy given customers’ views of the value contributed by reliable electric supply. The report concludes with findings and recommendations for reliability in the State of Hawaii.

  20. Reliability and performance of 808-nm single emitter multi-mode laser diodes

    NASA Astrophysics Data System (ADS)

    Wang, J.; Bao, L.; Devito, M.; Xu, D.; Wise, D.; Grimshaw, M.; Dong, W.; Zhang, S.; Bai, C.; Leisher, P.; Li, D.; Zhou, H.; Patterson, S.; Martinsen, R.; Haden, J.

    2010-02-01

    Performance, lifetest data, as well as failure modes from two different device structures will be discussed in this paper, with emitting wavelengths from 780nm to 800nm. The first structure, designed for high temperature operation, has demonstrated good reliability on various packages with output power up to 10W from a 200μm emitting area. The device structure can be operated up to 60°C heatsink temperatures under CW conditions. Then a high efficiency structure is shown with further improvement on operation power and reliability, for room temperature operation. With ongoing lifetest at 12A and 50°C heatsink temperature, <1000 FIT has been achieved for 6.5W and 33°C operation, on both designs. MTT10%F at 10W and 25°C operation is estimated to be more than 20,000 hours. Devices retain more than 20W rollover power under CW conditions, when re-tested after several thousand hours of accelerated lifetest. Paths for reliability improvement will also be discussed based on observed lifetest failure modes from these two structures.

  1. Estimating the Reliability of a Soyuz Spacecraft Mission

    NASA Technical Reports Server (NTRS)

    Lutomski, Michael G.; Farnham, Steven J., II; Grant, Warren C.

    2010-01-01

    Once the US Space Shuttle retires in 2010, the Russian Soyuz Launcher and Soyuz Spacecraft will comprise the only means for crew transportation to and from the International Space Station (ISS). The U.S. Government and NASA have contracted for crew transportation services to the ISS with Russia. The resulting implications for the US space program including issues such as astronaut safety must be carefully considered. Are the astronauts and cosmonauts safer on the Soyuz than the Space Shuttle system? Is the Soyuz launch system more robust than the Space Shuttle? Is it safer to continue to fly the 30 year old Shuttle fleet for crew transportation and cargo resupply than the Soyuz? Should we extend the life of the Shuttle Program? How does the development of the Orion/Ares crew transportation system affect these decisions? The Soyuz launcher has been in operation for over 40 years. There have been only two loss of life incidents and two loss of mission incidents. Given that the most recent incident took place in 1983, how do we determine current reliability of the system? Do failures of unmanned Soyuz rockets impact the reliability of the currently operational man-rated launcher? Does the Soyuz exhibit characteristics that demonstrate reliability growth and how would that be reflected in future estimates of success? NASA s next manned rocket and spacecraft development project is currently underway. Though the projects ultimate goal is to return to the Moon and then to Mars, the launch vehicle and spacecraft s first mission will be for crew transportation to and from the ISS. The reliability targets are currently several times higher than the Shuttle and possibly even the Soyuz. Can these targets be compared to the reliability of the Soyuz to determine whether they are realistic and achievable? To help answer these questions this paper will explore how to estimate the reliability of the Soyuz Launcher/Spacecraft system, compare it to the Space Shuttle, and its

  2. 18 CFR 40.2 - Mandatory Reliability Standards.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 18 Conservation of Power and Water Resources 1 2010-04-01 2010-04-01 false Mandatory Reliability..., DEPARTMENT OF ENERGY REGULATIONS UNDER THE FEDERAL POWER ACT MANDATORY RELIABILITY STANDARDS FOR THE BULK-POWER SYSTEM § 40.2 Mandatory Reliability Standards. (a) Each applicable user, owner or operator of...

  3. 75 FR 35689 - System Personnel Training Reliability Standards

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-06-23

    ... Energy Regulatory Commission 18 CFR Part 40 System Personnel Training Reliability Standards June 17, 2010... approve Reliability Standards PER-005-1 (System Personnel Training) and PER- 004-2 (Reliability... coordinators, balancing authorities, and transmission operators to establish a training program for...

  4. Reliability modelling and analysis of thermal MEMS

    NASA Astrophysics Data System (ADS)

    Muratet, Sylvaine; Lavu, Srikanth; Fourniols, Jean-Yves; Bell, George; Desmulliez, Marc P. Y.

    2006-04-01

    This paper presents a MEMS reliability study methodology based on the novel concept of 'virtual prototyping'. This methodology can be used for the development of reliable sensors or actuators and also to characterize their behaviour in specific use conditions and applications. The methodology is demonstrated on the U-shaped micro electro thermal actuator used as test vehicle. To demonstrate this approach, a 'virtual prototype' has been developed with the modeling tools MatLab and VHDL-AMS. A best practice FMEA (Failure Mode and Effect Analysis) is applied on the thermal MEMS to investigate and assess the failure mechanisms. Reliability study is performed by injecting the identified defaults into the 'virtual prototype'. The reliability characterization methodology predicts the evolution of the behavior of these MEMS as a function of the number of cycles of operation and specific operational conditions.

  5. Reliability of Search and Rescue Action

    NASA Astrophysics Data System (ADS)

    Burciu, Zbigniew

    2012-06-01

    Determination of the reliability of Search and Rescue action system allows the SAR Mission Coordinator to increase the effectiveness of the action through the proper selection of operational characteristics of the system elements, in particular the selection of the rescue units and auxiliary units. The paper presents the example of the influence of water temperature and time of the action on the reliability of search and rescue action in the case of rescuing a survivor in the water.

  6. Validation of reliability of fire extinguishers for medical pressure chambers

    NASA Astrophysics Data System (ADS)

    Kharisov, G. K.; Bubyr, N. F.

    1985-11-01

    During a fire in a medical pressure chamber when operated in the regular mode it is impossible to evacuate people, and the only way to save human lives is by extinguishing the fire. The level of reliability of fire extinguishers intended for pressure chamber is examined. In case of fire, the life of people in the chamber depends entirely on reliability of operation of the fire extinguisher. The reliability of equipment, including fire extinguishers, depends on the cost. By regulating the reliability of its cost is also regulated. At the present time no standards are set for parameters of reliability of equipment which protects people from the hazards of a fire.

  7. Reliability techniques in the petroleum industry

    NASA Technical Reports Server (NTRS)

    Williams, H. L.

    1971-01-01

    Quantitative reliability evaluation methods used in the Apollo Spacecraft Program are translated into petroleum industry requirements with emphasis on offsetting reliability demonstration costs and limited production runs. Described are the qualitative disciplines applicable, the definitions and criteria that accompany the disciplines, and the generic application of these disciplines to the chemical industry. The disciplines are then translated into proposed definitions and criteria for the industry, into a base-line reliability plan that includes these disciplines, and into application notes to aid in adapting the base-line plan to a specific operation.

  8. A Year of Exceptional Achievements FY 2008

    SciTech Connect

    devore, L; Chrzanowski, P

    2008-11-06

    2008 highlights: (1) Stockpile Stewardship and Complex Transformation - LLNL achieved scientific breakthroughs that explain some of the key 'unknowns' in nuclear weapons performance and are critical to developing the predictive science needed to ensure the safety, reliability, and security of the U.S. nuclear deterrent without nuclear testing. In addition, the National Ignition Facility (NIF) passed 99 percent completion, an LLNL supercomputer simulation won the 2007 Gordon Bell Prize, and a significant fraction of our inventory of special nuclear material was shipped to other sites in support of complex transformation. (2) National and Global Security - Laboratory researchers delivered insights, technologies, and operational capabilities that are helping to ensure national security and global stability. Of particular note, they developed advanced detection instruments that provide increased speed, accuracy, specificity, and resolution for identifying and characterizing biological, chemical, nuclear, and high-explosive threats. (3) Exceptional Science and Technology - The Laboratory continued its tradition of scientific excellence and technical innovation. LLNL scientists made significant contributions to Nobel Prize-winning work on climate change. LLNL also received three R&D 100 awards and six Nanotech 50 awards, and dozens of Laboratory scientists and engineers were recognized with professional awards. These honors provide valuable confirmation that peers and outside experts recognize the quality of our staff and our work. (4) Enhanced Business and Operations - A major thrust under LLNS is to make the Laboratory more efficient and cost competitive. We achieved roughly $75 million in cost savings for support activities through organizational changes, consolidation of services, improved governance structures and work processes, technology upgrades, and systems shared with Los Alamos National Laboratory. We realized nonlabor cost savings of $23 million. Severe

  9. The Challenge of Wireless Reliability and Coexistence.

    PubMed

    Berger, H Stephen

    2016-09-01

    Wireless communication plays an increasingly important role in healthcare delivery. This further heightens the importance of wireless reliability, but quantifying wireless reliability is a complex and difficult challenge. Understanding the risks that accompany the many benefits of wireless communication should be a component of overall risk management. The emerging trend of using sensors and other device-to-device communications, as part of the emerging Internet of Things concept, is evident in healthcare delivery. The trend increases both the importance and complexity of this challenge. As with most system problems, finding a solution requires breaking down the problem into manageable steps. Understanding the operational reliability of a new wireless device and its supporting system requires developing solid, quantified answers to three questions: 1) How well can this new device and its system operate in a spectral environment where many other wireless devices are also operating? 2) What is the spectral environment in which this device and its system are expected to operate? Are the risks and reliability in its operating environment acceptable? 3) How might the new device and its system affect other devices and systems already in use? When operated under an insightful risk management process, wireless technology can be safely implemented, resulting in improved delivery of care.

  10. The rating reliability calculator

    PubMed Central

    Solomon, David J

    2004-01-01

    Background Rating scales form an important means of gathering evaluation data. Since important decisions are often based on these evaluations, determining the reliability of rating data can be critical. Most commonly used methods of estimating reliability require a complete set of ratings i.e. every subject being rated must be rated by each judge. Over fifty years ago Ebel described an algorithm for estimating the reliability of ratings based on incomplete data. While his article has been widely cited over the years, software based on the algorithm is not readily available. This paper describes an easy-to-use Web-based utility for estimating the reliability of ratings based on incomplete data using Ebel's algorithm. Methods The program is available public use on our server and the source code is freely available under GNU General Public License. The utility is written in PHP, a common open source imbedded scripting language. The rating data can be entered in a convenient format on the user's personal computer that the program will upload to the server for calculating the reliability and other statistics describing the ratings. Results When the program is run it displays the reliability, number of subject rated, harmonic mean number of judges rating each subject, the mean and standard deviation of the averaged ratings per subject. The program also displays the mean, standard deviation and number of ratings for each subject rated. Additionally the program will estimate the reliability of an average of a number of ratings for each subject via the Spearman-Brown prophecy formula. Conclusion This simple web-based program provides a convenient means of estimating the reliability of rating data without the need to conduct special studies in order to provide complete rating data. I would welcome other researchers revising and enhancing the program. PMID:15117416

  11. Reliability, Availability and Maintainability Design Practices Guide. Volume 1,

    DTIC Science & Technology

    1981-03-01

    5-11 Reliability Prediction of Mechanical and Structural 2-5-12 Systems Applications of Helicopter Mockups to Maintainability and 2-5-13 Other...Equations APRDCT -Apportionment/ Prediction 4-1-11 Exact Minimal Path and Minimal Cut Techniques for 4-1-12a Determining System Reliability Reliability ...3-0 Cost Optimizing System to Evaluate Reliability (COSTER) 4-3-la Operating and Support Cost Model 4-3-2 The Avionics Laboratory Predictive

  12. Metrology automation reliability

    NASA Astrophysics Data System (ADS)

    Chain, Elizabeth E.

    1996-09-01

    At Motorola's MOS-12 facility automated measurements on 200- mm diameter wafers proceed in a hands-off 'load-and-go' mode requiring only wafer loading, measurement recipe loading, and a 'run' command for processing. Upon completion of all sample measurements, the data is uploaded to the factory's data collection software system via a SECS II interface, eliminating the requirement of manual data entry. The scope of in-line measurement automation has been extended to the entire metrology scheme from job file generation to measurement and data collection. Data analysis and comparison to part specification limits is also carried out automatically. Successful integration of automated metrology into the factory measurement system requires that automated functions, such as autofocus and pattern recognition algorithms, display a high degree of reliability. In the 24- hour factory reliability data can be collected automatically on every part measured. This reliability data is then uploaded to the factory data collection software system at the same time as the measurement data. Analysis of the metrology reliability data permits improvements to be made as needed, and provides an accurate accounting of automation reliability. This reliability data has so far been collected for the CD-SEM (critical dimension scanning electron microscope) metrology tool, and examples are presented. This analysis method can be applied to such automated in-line measurements as CD, overlay, particle and film thickness measurements.

  13. Calculation reliability in vehicle accident reconstruction.

    PubMed

    Wach, Wojciech

    2016-06-01

    The reconstruction of vehicle accidents is subject to assessment in terms of the reliability of a specific system of engineering and technical operations. In the article [26] a formalized concept of the reliability of vehicle accident reconstruction, defined using Bayesian networks, was proposed. The current article is focused on the calculation reliability since that is the most objective section of this model. It is shown that calculation reliability in accident reconstruction is not another form of calculation uncertainty. The calculation reliability is made dependent on modeling reliability, adequacy of the model and relative uncertainty of calculation. All the terms are defined. An example is presented concerning the analytical determination of the collision location of two vehicles on the road in the absence of evidential traces. It has been proved that the reliability of this kind of calculations generally does not exceed 0.65, despite the fact that the calculation uncertainty itself can reach only 0.05. In this example special attention is paid to the analysis of modeling reliability and calculation uncertainty using sensitivity coefficients and weighted relative uncertainty.

  14. Accurate, reliable prototype earth horizon sensor head

    NASA Technical Reports Server (NTRS)

    Schwarz, F.; Cohen, H.

    1973-01-01

    The design and performance is described of an accurate and reliable prototype earth sensor head (ARPESH). The ARPESH employs a detection logic 'locator' concept and horizon sensor mechanization which should lead to high accuracy horizon sensing that is minimally degraded by spatial or temporal variations in sensing attitude from a satellite in orbit around the earth at altitudes in the 500 km environ 1,2. An accuracy of horizon location to within 0.7 km has been predicted, independent of meteorological conditions. This corresponds to an error of 0.015 deg-at 500 km altitude. Laboratory evaluation of the sensor indicates that this accuracy is achieved. First, the basic operating principles of ARPESH are described; next, detailed design and construction data is presented and then performance of the sensor under laboratory conditions in which the sensor is installed in a simulator that permits it to scan over a blackbody source against background representing the earth space interface for various equivalent plant temperatures.

  15. Gearbox Reliability Collaborative Phase 3 Gearbox 2 Test Plan

    SciTech Connect

    Link, H.; Keller, J.; Guo, Y.; McNiff, B.

    2013-04-01

    Gearboxes in wind turbines have not been achieving their expected design life even though they commonly meet or exceed the design criteria specified in current design standards. One of the basic premises of the National Renewable Energy Laboratory (NREL) Gearbox Reliability Collaborative (GRC) is that the low gearbox reliability results from the absence of critical elements in the design process or insufficient design tools. Key goals of the GRC are to improve design approaches and analysis tools and to recommend practices and test methods resulting in improved design standards for wind turbine gearboxes that lower the cost of energy (COE) through improved reliability. The GRC uses a combined gearbox testing, modeling and analysis approach, along with a database of information from gearbox failures collected from overhauls and investigation of gearbox condition monitoring techniques to improve wind turbine operations and maintenance practices. Testing of Gearbox 2 (GB2) using the two-speed turbine controller that has been used in prior testing. This test series will investigate non-torque loads, high-speed shaft misalignment, and reproduction of field conditions in the dynamometer. This test series will also include vibration testing using an eddy-current brake on the gearbox's high speed shaft.

  16. Maximally reliable spatial filtering of steady state visual evoked potentials.

    PubMed

    Dmochowski, Jacek P; Greaves, Alex S; Norcia, Anthony M

    2015-04-01

    Due to their high signal-to-noise ratio (SNR) and robustness to artifacts, steady state visual evoked potentials (SSVEPs) are a popular technique for studying neural processing in the human visual system. SSVEPs are conventionally analyzed at individual electrodes or linear combinations of electrodes which maximize some variant of the SNR. Here we exploit the fundamental assumption of evoked responses--reproducibility across trials--to develop a technique that extracts a small number of high SNR, maximally reliable SSVEP components. This novel spatial filtering method operates on an array of Fourier coefficients and projects the data into a low-dimensional space in which the trial-to-trial spectral covariance is maximized. When applied to two sample data sets, the resulting technique recovers physiologically plausible components (i.e., the recovered topographies match the lead fields of the underlying sources) while drastically reducing the dimensionality of the data (i.e., more than 90% of the trial-to-trial reliability is captured in the first four components). Moreover, the proposed technique achieves a higher SNR than that of the single-best electrode or the Principal Components. We provide a freely-available MATLAB implementation of the proposed technique, herein termed "Reliable Components Analysis".

  17. An approximation formula for a class of Markov reliability models

    NASA Technical Reports Server (NTRS)

    White, A. L.

    1984-01-01

    A way of considering a small but often used class of reliability model and approximating algebraically the systems reliability is shown. The models considered are appropriate for redundant reconfigurable digital control systems that operate for a short period of time without maintenance, and for such systems the method gives a formula in terms of component fault rates, system recovery rates, and system operating time.

  18. Reliability on ISS Talk Outline

    NASA Technical Reports Server (NTRS)

    Misiora, Mike

    2015-01-01

    1. Overview of ISS 2. Space Environment and it effects a. Radiation b. Microgravity 3. How we ensure reliability a. Requirements b. Component Selection i. Note: I plan to stay away from talk about Rad Hardened components and talk about why we use older processors because they are less susceptible to SEUs. c. Testing d. Redundancy / Failure Tolerance e. Sparing strategies 4. Operational Examples a. Multiple MDM Failures on 6A due to hard drive failure In general, my plan is to only talk about data that is currently available via normal internet sources to ensure that I stay away from any topics that would be Export Controlled, ITAR, or NDA-controlled. The operational example has been well-reported on in the media and those are the details that I plan to cover. Additionally I am not planning on using any slides or showing any photos during the talk.

  19. Development of brain systems for nonsymbolic numerosity and the relationship to formal math academic achievement.

    PubMed

    Haist, Frank; Wazny, Jarnet H; Toomarian, Elizabeth; Adamo, Maha

    2015-02-01

    A central question in cognitive and educational neuroscience is whether brain operations supporting nonlinguistic intuitive number sense (numerosity) predict individual acquisition and academic achievement for symbolic or "formal" math knowledge. Here, we conducted a developmental functional magnetic resonance imaging (MRI) study of nonsymbolic numerosity task performance in 44 participants including 14 school age children (6-12 years old), 14 adolescents (13-17 years old), and 16 adults and compared a brain activity measure of numerosity precision to scores from the Woodcock-Johnson III Broad Math index of math academic achievement. Accuracy and reaction time from the numerosity task did not reliably predict formal math achievement. We found a significant positive developmental trend for improved numerosity precision in the parietal cortex and intraparietal sulcus specifically. Controlling for age and overall cognitive ability, we found a reliable positive relationship between individual math achievement scores and parietal lobe activity only in children. In addition, children showed robust positive relationships between math achievement and numerosity precision within ventral stream processing areas bilaterally. The pattern of results suggests a dynamic developmental trajectory for visual discrimination strategies that predict the acquisition of formal math knowledge. In adults, the efficiency of visual discrimination marked by numerosity acuity in ventral occipital-temporal cortex and hippocampus differentiated individuals with better or worse formal math achievement, respectively. Overall, these results suggest that two different brain systems for nonsymbolic numerosity acuity may contribute to individual differences in math achievement and that the contribution of these systems differs across development.

  20. Photovoltaic-reliability R&D toward a solar-powered world

    NASA Astrophysics Data System (ADS)

    Kurtz, Sarah; Granata, Jennifer; Quintana, Michael

    2009-08-01

    The continued exponential growth of photovoltaic technologies paves a path to a solar-powered world, but requires continued progress toward low-cost, high-reliability, and high-performance PV systems. High reliability is an essential element in achieving low-cost solar electricity by reducing operation and maintenance (O&M) costs and by extending system lifetime and availability, but these attributes are difficult to verify at the time of installation. Utilities, financiers, homeowners, and planners are demanding this information in order to evaluate their financial risk as a prerequisite to large investments. Reliability research and development (R&D) is needed to build market confidence by improving product reliability and by improving predictions of system availability, O&M cost, and system lifetime. Universities, industry, National Labs, and other research entities can be most effective by working together and in complementary ways. The Department of Energy supports a variety of research projects to improve PV-system reliability. These projects and current reliability issues for each PV technology are surveyed.

  1. Reliability and availability requirements analysis for DEMO: fuel cycle system

    SciTech Connect

    Pinna, T.; Borgognoni, F.

    2015-03-15

    The Demonstration Power Plant (DEMO) will be a fusion reactor prototype designed to demonstrate the capability to produce electrical power in a commercially acceptable way. Two of the key elements of the engineering development of the DEMO reactor are the definitions of reliability and availability requirements (or targets). The availability target for a hypothesized Fuel Cycle has been analysed as a test case. The analysis has been done on the basis of the experience gained in operating existing tokamak fusion reactors and developing the ITER design. Plant Breakdown Structure (PBS) and Functional Breakdown Structure (FBS) related to the DEMO Fuel Cycle and correlations between PBS and FBS have been identified. At first, a set of availability targets has been allocated to the various systems on the basis of their operating, protection and safety functions. 75% and 85% of availability has been allocated to the operating functions of fuelling system and tritium plant respectively. 99% of availability has been allocated to the overall systems in executing their safety functions. The chances of the systems to achieve the allocated targets have then been investigated through a Failure Mode and Effect Analysis and Reliability Block Diagram analysis. The following results have been obtained: 1) the target of 75% for the operations of the fuelling system looks reasonable, while the target of 85% for the operations of the whole tritium plant should be reduced to 80%, even though all the tritium plant systems can individually reach quite high availability targets, over 90% - 95%; 2) all the DEMO Fuel Cycle systems can reach the target of 99% in accomplishing their safety functions. (authors)

  2. Back to the Basics: In Defense of Achievement (and Achievement Tests) in College Admissions

    ERIC Educational Resources Information Center

    Geiser, Saul

    2009-01-01

    In this article, the author describes the growth and acceptance of achievement tests, such as the Scholastic Aptitude Test (SAT), over the past century, advocating that many SAT claims of equity, uniformity, technical reliability, and prediction, over traditional measures of academic achievement have been found to be illusory. Summarizing a series…

  3. Test Reliability by Ability Level of Examinees.

    ERIC Educational Resources Information Center

    Green, Kathy; Sax, Gilbert

    Achievement test reliability as a function of ability was determined for multiple sections of a large university French class (n=193). A 5-option multiple-choice examination was constructed, least attractive distractors were eliminated based on the instructor's judgment, and the resulting three forms of the examination (i.e. 3-, 4-, or 5-choice…

  4. Flight control electronics reliability/maintenance study

    NASA Technical Reports Server (NTRS)

    Dade, W. W.; Edwards, R. H.; Katt, G. T.; Mcclellan, K. L.; Shomber, H. A.

    1977-01-01

    Collection and analysis of data are reported that concern the reliability and maintenance experience of flight control system electronics currently in use on passenger carrying jet aircraft. Two airlines B-747 airplane fleets were analyzed to assess the component reliability, system functional reliability, and achieved availability of the CAT II configuration flight control system. Also assessed were the costs generated by this system in the categories of spare equipment, schedule irregularity, and line and shop maintenance. The results indicate that although there is a marked difference in the geographic location and route pattern between the airlines studied, there is a close similarity in the reliability and the maintenance costs associated with the flight control electronics.

  5. Reliable reactor coolant pump seal performance - the station's role

    SciTech Connect

    Pothier, N.E.; Metcalfe, R.

    1989-01-01

    During the early days of the Canada deuterium uranium (CANDU) power reactor program, operators and designers learned that close attention to reactor coolant pump (RCP) seals was imperative for achieving high-capacity factors. This lesson was driven home by unpredictable and frequent seal failures in the following early CANDU plants. Those seal failures caused forced outages, maintenance/dose burdens, and heavy-water losses. Because then-available industrial seal technology proved inadequate in providing satisfactory fixes, Atomic Energy of Canada Limited (AECL) began a major effort to understand seal performance, develop improved designs, and evolve the station technology needed to attain the RCP seal reliable lifetime requirement of 4 yr. The payback has been huge: Fixes have been successfully implemented and excellent performance is now being achieved with AECL improved RCP seals. In this paper, the CANDU RCP seal experience, the methodology (with emphasis on the station's role) for attaining reliable long RCP seal life, and the adaptability of this technology to US light water reactors (LWRs) are discussed.

  6. Statistical modelling of software reliability

    NASA Technical Reports Server (NTRS)

    Miller, Douglas R.

    1991-01-01

    During the six-month period from 1 April 1991 to 30 September 1991 the following research papers in statistical modeling of software reliability appeared: (1) A Nonparametric Software Reliability Growth Model; (2) On the Use and the Performance of Software Reliability Growth Models; (3) Research and Development Issues in Software Reliability Engineering; (4) Special Issues on Software; and (5) Software Reliability and Safety.

  7. Photovoltaic module reliability workshop

    SciTech Connect

    Mrig, L.

    1990-01-01

    The paper and presentations compiled in this volume form the Proceedings of the fourth in a series of Workshops sponsored by Solar Energy Research Institute (SERI/DOE) under the general theme of photovoltaic module reliability during the period 1986--1990. The reliability Photo Voltaic (PV) modules/systems is exceedingly important along with the initial cost and efficiency of modules if the PV technology has to make a major impact in the power generation market, and for it to compete with the conventional electricity producing technologies. The reliability of photovoltaic modules has progressed significantly in the last few years as evidenced by warranties available on commercial modules of as long as 12 years. However, there is still need for substantial research and testing required to improve module field reliability to levels of 30 years or more. Several small groups of researchers are involved in this research, development, and monitoring activity around the world. In the US, PV manufacturers, DOE laboratories, electric utilities and others are engaged in the photovoltaic reliability research and testing. This group of researchers and others interested in this field were brought together under SERI/DOE sponsorship to exchange the technical knowledge and field experience as related to current information in this important field. The papers presented here reflect this effort.

  8. Photovoltaic module reliability workshop

    NASA Astrophysics Data System (ADS)

    Mrig, L.

    The paper and presentations compiled in this volume form the Proceedings of the fourth in a series of Workshops sponsored by Solar Energy Research Institute (SERI/DOE) under the general theme of photovoltaic module reliability during the period 1986 to 1990. The reliability photovoltaic (PV) modules/systems is exceedingly important along with the initial cost and efficiency of modules if the PV technology has to make a major impact in the power generation market, and for it to compete with the conventional electricity producing technologies. The reliability of photovoltaic modules has progressed significantly in the last few years as evidenced by warrantees available on commercial modules of as long as 12 years. However, there is still need for substantial research and testing required to improve module field reliability to levels of 30 years or more. Several small groups of researchers are involved in this research, development, and monitoring activity around the world. In the U.S., PV manufacturers, DOE laboratories, electric utilities and others are engaged in the photovoltaic reliability research and testing. This group of researchers and others interested in this field were brought together under SERI/DOE sponsorship to exchange the technical knowledge and field experience as related to current information in this important field. The papers presented here reflect this effort.

  9. Orbiter Autoland reliability analysis

    NASA Technical Reports Server (NTRS)

    Welch, D. Phillip

    1993-01-01

    The Space Shuttle Orbiter is the only space reentry vehicle in which the crew is seated upright. This position presents some physiological effects requiring countermeasures to prevent a crewmember from becoming incapacitated. This also introduces a potential need for automated vehicle landing capability. Autoland is a primary procedure that was identified as a requirement for landing following and extended duration orbiter mission. This report documents the results of the reliability analysis performed on the hardware required for an automated landing. A reliability block diagram was used to evaluate system reliability. The analysis considers the manual and automated landing modes currently available on the Orbiter. (Autoland is presently a backup system only.) Results of this study indicate a +/- 36 percent probability of successfully extending a nominal mission to 30 days. Enough variations were evaluated to verify that the reliability could be altered with missions planning and procedures. If the crew is modeled as being fully capable after 30 days, the probability of a successful manual landing is comparable to that of Autoland because much of the hardware is used for both manual and automated landing modes. The analysis indicates that the reliability for the manual mode is limited by the hardware and depends greatly on crew capability. Crew capability for a successful landing after 30 days has not been determined yet.

  10. Proposed reliability cost model

    NASA Technical Reports Server (NTRS)

    Delionback, L. M.

    1973-01-01

    The research investigations which were involved in the study include: cost analysis/allocation, reliability and product assurance, forecasting methodology, systems analysis, and model-building. This is a classic example of an interdisciplinary problem, since the model-building requirements include the need for understanding and communication between technical disciplines on one hand, and the financial/accounting skill categories on the other. The systems approach is utilized within this context to establish a clearer and more objective relationship between reliability assurance and the subcategories (or subelements) that provide, or reenforce, the reliability assurance for a system. Subcategories are further subdivided as illustrated by a tree diagram. The reliability assurance elements can be seen to be potential alternative strategies, or approaches, depending on the specific goals/objectives of the trade studies. The scope was limited to the establishment of a proposed reliability cost-model format. The model format/approach is dependent upon the use of a series of subsystem-oriented CER's and sometimes possible CTR's, in devising a suitable cost-effective policy.

  11. Science Operations on the Lunar Surface - Understanding the Past, Testing in the Present, Considering the Future

    NASA Technical Reports Server (NTRS)

    Eppler, Dean B.

    2013-01-01

    The scientific success of any future human lunar exploration mission will be strongly dependent on design of both the systems and operations practices that underpin crew operations on the lunar surface. Inept surface mission preparation and design will either ensure poor science return, or will make achieving quality science operation unacceptably difficult for the crew and the mission operations and science teams. In particular, ensuring a robust system for managing real-time science information flow during surface operations, and ensuring the crews receive extensive field training in geological sciences, are as critical to mission success as reliable spacecraft and a competent operations team.

  12. Reliability, Maintainability, and Availability: Consideration During the Design Phase in Ground Systems to Ensure Successful Launch Support

    NASA Technical Reports Server (NTRS)

    Gillespie, Amanda M.

    2012-01-01

    The future of Space Exploration includes missions to the moon, asteroids, Mars, and beyond. To get there, the mission concept is to launch multiple launch vehicles months, even years apart. In order to achieve this, launch vehicles, payloads (satellites and crew capsules), and ground systems must be highly reliable and/or available, to include maintenance concepts and procedures in the event of a launch scrub. In order to achieve this high probability of mission success, Ground Systems Development and Operations (GSDO) has allocated Reliability, Maintainability, and Availability (RMA) requirements to all hardware and software required for both launch operations and, in the event of a launch scrub, required to support a repair of the ground systems, launch vehicle, or payload. This is done concurrently with the design process (30/60/90 reviews).

  13. Leader as achiever.

    PubMed

    Dienemann, Jacqueline

    2002-01-01

    This article examines one outcome of leadership: productive achievement. Without achievement one is judged to not truly be a leader. Thus, the ideal leader must be a visionary, a critical thinker, an expert, a communicator, a mentor, and an achiever of organizational goals. This article explores the organizational context that supports achievement, measures of quality nursing care, fiscal accountability, leadership development, rewards and punishments, and the educational content and teaching strategies to prepare graduates to be achievers.

  14. Gearbox Reliability Collaborative Update (Presentation)

    SciTech Connect

    Sheng, S.; Keller, J.; Glinsky, C.

    2013-10-01

    This presentation was given at the Sandia Reliability Workshop in August 2013 and provides information on current statistics, a status update, next steps, and other reliability research and development activities related to the Gearbox Reliability Collaborative.

  15. Continuous Reliability Enhancement for Wind (CREW) database :

    SciTech Connect

    Hines, Valerie Ann-Peters; Ogilvie, Alistair B.; Bond, Cody R.

    2013-09-01

    To benchmark the current U.S. wind turbine fleet reliability performance and identify the major contributors to component-level failures and other downtime events, the Department of Energy funded the development of the Continuous Reliability Enhancement for Wind (CREW) database by Sandia National Laboratories. This report is the third annual Wind Plant Reliability Benchmark, to publically report on CREW findings for the wind industry. The CREW database uses both high resolution Supervisory Control and Data Acquisition (SCADA) data from operating plants and Strategic Power Systems ORAPWindª (Operational Reliability Analysis Program for Wind) data, which consist of downtime and reserve event records and daily summaries of various time categories for each turbine. Together, these data are used as inputs into CREWs reliability modeling. The results presented here include: the primary CREW Benchmark statistics (operational availability, utilization, capacity factor, mean time between events, and mean downtime); time accounting from an availability perspective; time accounting in terms of the combination of wind speed and generation levels; power curve analysis; and top system and component contributors to unavailability.

  16. Reliability and Failure in NASA Missions: Blunders, Normal Accidents, High Reliability, Bad Luck

    NASA Technical Reports Server (NTRS)

    Jones, Harry W.

    2015-01-01

    NASA emphasizes crew safety and system reliability but several unfortunate failures have occurred. The Apollo 1 fire was mistakenly unanticipated. After that tragedy, the Apollo program gave much more attention to safety. The Challenger accident revealed that NASA had neglected safety and that management underestimated the high risk of shuttle. Probabilistic Risk Assessment was adopted to provide more accurate failure probabilities for shuttle and other missions. NASA's "faster, better, cheaper" initiative and government procurement reform led to deliberately dismantling traditional reliability engineering. The Columbia tragedy and Mars mission failures followed. Failures can be attributed to blunders, normal accidents, or bad luck. Achieving high reliability is difficult but possible.

  17. MOV reliability evaluation and periodic verification scheduling

    SciTech Connect

    Bunte, B.D.

    1996-12-01

    The purpose of this paper is to establish a periodic verification testing schedule based on the expected long term reliability of gate or globe motor operated valves (MOVs). The methodology in this position paper determines the nominal (best estimate) design margin for any MOV based on the best available information pertaining to the MOVs design requirements, design parameters, existing hardware design, and present setup. The uncertainty in this margin is then determined using statistical means. By comparing the nominal margin to the uncertainty, the reliability of the MOV is estimated. The methodology is appropriate for evaluating the reliability of MOVs in the GL 89-10 program. It may be used following periodic testing to evaluate and trend MOV performance and reliability. It may also be used to evaluate the impact of proposed modifications and maintenance activities such as packing adjustments. In addition, it may be used to assess the impact of new information of a generic nature which impacts safety related MOVs.

  18. South Africa and the 21st Century Power Partnership: Paving the Way to a Clean, Reliable, and Resilient Power System

    SciTech Connect

    None, None

    2016-05-01

    Established in 2012, the 21CPP South Africa Programme is a global initiative that connects South African stakeholders with an international community
    of expertise. The overall goal of this program is to support South Africa's power system transformation by accelerating the transition to a reliable, financially robust, and low-carbon power system. 21CPP activities focus on achieving positive outcomes for all participants, especially addressing critical questions and challenges facing system planners, regulators, and operators.

  19. Reliability-based pricing of electricity service

    SciTech Connect

    Hagazy, Y.A.

    1993-01-01

    This research has two objectives: (a) to develop a price structure that unbundles electricity service by reliability levels, and (b) to analyze the implications of such a structure on economic welfare, system operation, load management, and energy conservation. The authors developed a pricing mechanism for electricity service that combines priority (reliability differentiation) pricing with real-time Ramsey type pricing. The electric utility is assumed to be a single welfare-maximizing firm able to set and communicate prices instantly. At time of supply shortages, the utility has direct control over customer loads and follows a rationing method among customers willing to accept power interruptions. Therefore, customers are given the choice either to be served with a high reliability [open quotes]firm[close quotes] service, or to be subject to interruption. To encourage customers to make rational reliability choices, a payment/compensation mechanism was integrated into the welfare-maximization model. In order to account for uncertainties associated with the operation of electric power systems, a stochastic production cost simulation is also integrated with the model. The stochastic production cost simulation yields the estimation of the expected production, cost, marginal costs, and system reliability level at total demand. The authors examine the welfare gain and energy and reserve saving possibilities due to different pricing schemes. The results show that reliability-based pricing yields higher economic efficiency and energy and power saving than both spot and Ramsey pricing when system imperfect reliability is considered. Therefore, the implication of this research is that reliability-based pricing provides a feasible solution to electric utilities as a substitute for power purchases, and/or new capacity investment.

  20. Assuring Software Reliability

    DTIC Science & Technology

    2014-08-01

    resources.sei.cmu.edu/asset_files/WhitePaper/2009_019_001_29066.pdf [Boydston 2009] Boydston, A. & Lewis , W. Qualification and Reliability of...Woody, Carol . Survivability Analysis Framework (CMU/SEI-2010-TN-013). Software Engineering Institute, Carnegie Mellon University, 2010. http

  1. Parametric Mass Reliability Study

    NASA Technical Reports Server (NTRS)

    Holt, James P.

    2014-01-01

    The International Space Station (ISS) systems are designed based upon having redundant systems with replaceable orbital replacement units (ORUs). These ORUs are designed to be swapped out fairly quickly, but some are very large, and some are made up of many components. When an ORU fails, it is replaced on orbit with a spare; the failed unit is sometimes returned to Earth to be serviced and re-launched. Such a system is not feasible for a 500+ day long-duration mission beyond low Earth orbit. The components that make up these ORUs have mixed reliabilities. Components that make up the most mass-such as computer housings, pump casings, and the silicon board of PCBs-typically are the most reliable. Meanwhile components that tend to fail the earliest-such as seals or gaskets-typically have a small mass. To better understand the problem, my project is to create a parametric model that relates both the mass of ORUs to reliability, as well as the mass of ORU subcomponents to reliability.

  2. Sequential Reliability Tests.

    ERIC Educational Resources Information Center

    Eiting, Mindert H.

    1991-01-01

    A method is proposed for sequential evaluation of reliability of psychometric instruments. Sample size is unfixed; a test statistic is computed after each person is sampled and a decision is made in each stage of the sampling process. Results from a series of Monte-Carlo experiments establish the method's efficiency. (SLD)

  3. Designing reliability into accelerators

    SciTech Connect

    Hutton, A.

    1992-08-01

    For the next generation of high performance, high average luminosity colliders, the ``factories,`` reliability engineering must be introduced right at the inception of the project and maintained as a central theme throughout the project. There are several aspects which will be addressed separately: Concept; design; motivation; management techniques; and fault diagnosis.

  4. Designing reliability into accelerators

    SciTech Connect

    Hutton, A.

    1992-08-01

    For the next generation of high performance, high average luminosity colliders, the factories,'' reliability engineering must be introduced right at the inception of the project and maintained as a central theme throughout the project. There are several aspects which will be addressed separately: Concept; design; motivation; management techniques; and fault diagnosis.

  5. Reliable solar cookers

    SciTech Connect

    Magney, G.K.

    1992-12-31

    The author describes the activities of SERVE, a Christian relief and development agency, to introduce solar ovens to the Afghan refugees in Pakistan. It has provided 5,000 solar cookers since 1984. The experience has demonstrated the potential of the technology and the need for a durable and reliable product. Common complaints about the cookers are discussed and the ideal cooker is described.

  6. Software reliability report

    NASA Technical Reports Server (NTRS)

    Wilson, Larry

    1991-01-01

    There are many software reliability models which try to predict future performance of software based on data generated by the debugging process. Unfortunately, the models appear to be unable to account for the random nature of the data. If the same code is debugged multiple times and one of the models is used to make predictions, intolerable variance is observed in the resulting reliability predictions. It is believed that data replication can remove this variance in lab type situations and that it is less than scientific to talk about validating a software reliability model without considering replication. It is also believed that data replication may prove to be cost effective in the real world, thus the research centered on verification of the need for replication and on methodologies for generating replicated data in a cost effective manner. The context of the debugging graph was pursued by simulation and experimentation. Simulation was done for the Basic model and the Log-Poisson model. Reasonable values of the parameters were assigned and used to generate simulated data which is then processed by the models in order to determine limitations on their accuracy. These experiments exploit the existing software and program specimens which are in AIR-LAB to measure the performance of reliability models.

  7. Reliable vision-guided grasping

    NASA Technical Reports Server (NTRS)

    Nicewarner, Keith E.; Kelley, Robert B.

    1992-01-01

    Automated assembly of truss structures in space requires vision-guided servoing for grasping a strut when its position and orientation are uncertain. This paper presents a methodology for efficient and robust vision-guided robot grasping alignment. The vision-guided grasping problem is related to vision-guided 'docking' problems. It differs from other hand-in-eye visual servoing problems, such as tracking, in that the distance from the target is a relevant servo parameter. The methodology described in this paper is hierarchy of levels in which the vision/robot interface is decreasingly 'intelligent,' and increasingly fast. Speed is achieved primarily by information reduction. This reduction exploits the use of region-of-interest windows in the image plane and feature motion prediction. These reductions invariably require stringent assumptions about the image. Therefore, at a higher level, these assumptions are verified using slower, more reliable methods. This hierarchy provides for robust error recovery in that when a lower-level routine fails, the next-higher routine will be called and so on. A working system is described which visually aligns a robot to grasp a cylindrical strut. The system uses a single camera mounted on the end effector of a robot and requires only crude calibration parameters. The grasping procedure is fast and reliable, with a multi-level error recovery system.

  8. System reliability, performance and trust in adaptable automation.

    PubMed

    Chavaillaz, Alain; Wastell, David; Sauer, Jürgen

    2016-01-01

    The present study examined the effects of reduced system reliability on operator performance and automation management in an adaptable automation environment. 39 operators were randomly assigned to one of three experimental groups: low (60%), medium (80%), and high (100%) reliability of automation support. The support system provided five incremental levels of automation which operators could freely select according to their needs. After 3 h of training on a simulated process control task (AutoCAMS) in which the automation worked infallibly, operator performance and automation management were measured during a 2.5-h testing session. Trust and workload were also assessed through questionnaires. Results showed that although reduced system reliability resulted in lower levels of trust towards automation, there were no corresponding differences in the operators' reliance on automation. While operators showed overall a noteworthy ability to cope with automation failure, there were, however, decrements in diagnostic speed and prospective memory with lower reliability.

  9. Reliability Generalization (RG) Analysis: The Test Is Not Reliable

    ERIC Educational Resources Information Center

    Warne, Russell

    2008-01-01

    Literature shows that most researchers are unaware of some of the characteristics of reliability. This paper clarifies some misconceptions by describing the procedures, benefits, and limitations of reliability generalization while using it to illustrate the nature of score reliability. Reliability generalization (RG) is a meta-analytic method…

  10. Reliability and Uncertainty in Situational Awareness

    DTIC Science & Technology

    2006-12-01

    6 RTO-MP-IST-063 Reliability and Uncertainty in Situation Awareness Presented by: Glen Nakamoto Tom Johansen Group 3 2 Members David Hall Glen... Nakamoto D. M. Akbar Hussain Tom Johansen Vera Kamp Kesh Kesavadas 3 Motivation –Current Reality Operational Tempo Short Decision Time High Stress

  11. System reliability analysis through corona testing

    NASA Technical Reports Server (NTRS)

    Lalli, V. R.; Mueller, L. A.; Koutnik, E. A.

    1975-01-01

    In the Reliability and Quality Engineering Test Laboratory at the NASA Lewis Research Center a nondestructive, corona-vacuum test facility for testing power system components was developed using commercially available hardware. The test facility was developed to simulate operating temperature and vacuum while monitoring corona discharges with residual gases. This facility is being used to test various high voltage power system components.

  12. System reliability analysis through corona testing

    NASA Technical Reports Server (NTRS)

    Lalli, V. R.; Mueller, L. A.; Koutnik, E. A.

    1975-01-01

    A corona vacuum test facility for nondestructive testing of power system components was built in the Reliability and Quality Engineering Test Laboratories at the NASA Lewis Research Center. The facility was developed to simulate operating temperature and vacuum while monitoring corona discharges with residual gases. The facility is being used to test various high-voltage power system components.

  13. Teacher Involvement To Evaluate Science Achievement.

    ERIC Educational Resources Information Center

    Ediger, Marlow

    Teacher-developed tests can be more valid and reliable than standardized tests or state-mandated tests in evaluating student achievement in science. Many teachers, however, are not acquainted with the standards to use in test writing. The National Research Council has released "Classroom Assessment and the National Education Standards," a…

  14. Three brief assessments of math achievement.

    PubMed

    Steiner, Eric T; Ashcraft, Mark H

    2012-12-01

    Because of wide disparities in college students' math knowledge-that is, their math achievement-studies of cognitive processing in math tasks also need to assess their individual level of math achievement. For many research settings, however, using existing math achievement tests is either too costly or too time consuming. To solve this dilemma, we present three brief tests of math achievement here, two drawn from the Wide Range Achievement Test and one composed of noncopyrighted items. All three correlated substantially with the full achievement test and with math anxiety, our original focus, and all show acceptable to excellent reliability. When lengthy testing is not feasible, one of these brief tests can be substituted.

  15. Reliability Degradation Due to Stockpile Aging

    SciTech Connect

    Robinson, David G.

    1999-04-01

    The objective of this reseach is the investigation of alternative methods for characterizing the reliability of systems with time dependent failure modes associated with stockpile aging. Reference to 'reliability degradation' has, unfortunately, come to be associated with all types of aging analyes: both deterministic and stochastic. In this research, in keeping with the true theoretical definition, reliability is defined as a probabilistic description of system performance as a funtion of time. Traditional reliability methods used to characterize stockpile reliability depend on the collection of a large number of samples or observations. Clearly, after the experiments have been performed and the data has been collected, critical performance problems can be identified. A Major goal of this research is to identify existing methods and/or develop new mathematical techniques and computer analysis tools to anticipate stockpile problems before they become critical issues. One of the most popular methods for characterizing the reliability of components, particularly electronic components, assumes that failures occur in a completely random fashion, i.e. uniformly across time. This method is based primarily on the use of constant failure rates for the various elements that constitute the weapon system, i.e. the systems do not degrade while in storage. Experience has shown that predictions based upon this approach should be regarded with great skepticism since the relationship between the life predicted and the observed life has been difficult to validate. In addition to this fundamental problem, the approach does not recognize that there are time dependent material properties and variations associated with the manufacturing process and the operational environment. To appreciate the uncertainties in predicting system reliability a number of alternative methods are explored in this report. All of the methods are very different from those currently used to assess stockpile

  16. Multi-Disciplinary System Reliability Analysis

    NASA Technical Reports Server (NTRS)

    Mahadevan, Sankaran; Han, Song

    1997-01-01

    The objective of this study is to develop a new methodology for estimating the reliability of engineering systems that encompass multiple disciplines. The methodology is formulated in the context of the NESSUS probabilistic structural analysis code developed under the leadership of NASA Lewis Research Center. The NESSUS code has been successfully applied to the reliability estimation of a variety of structural engineering systems. This study examines whether the features of NESSUS could be used to investigate the reliability of systems in other disciplines such as heat transfer, fluid mechanics, electrical circuits etc., without considerable programming effort specific to each discipline. In this study, the mechanical equivalence between system behavior models in different disciplines are investigated to achieve this objective. A new methodology is presented for the analysis of heat transfer, fluid flow, and electrical circuit problems using the structural analysis routines within NESSUS, by utilizing the equivalence between the computational quantities in different disciplines. This technique is integrated with the fast probability integration and system reliability techniques within the NESSUS code, to successfully compute the system reliability of multi-disciplinary systems. Traditional as well as progressive failure analysis methods for system reliability estimation are demonstrated, through a numerical example of a heat exchanger system involving failure modes in structural, heat transfer and fluid flow disciplines.

  17. Comparing Science Achievement Constructs: Targeted and Achieved

    ERIC Educational Resources Information Center

    Ferrara, Steve; Duncan, Teresa

    2011-01-01

    This article illustrates how test specifications based solely on academic content standards, without attention to other cognitive skills and item response demands, can fall short of their targeted constructs. First, the authors inductively describe the science achievement construct represented by a statewide sixth-grade science proficiency test.…

  18. Which Achievement Gap?

    ERIC Educational Resources Information Center

    Anderson, Sharon; Medrich, Elliott; Fowler, Donna

    2007-01-01

    From the halls of Congress to the local elementary school, conversations on education reform have tossed around the term "achievement gap" as though people all know precisely what that means. As it's commonly used, "achievement gap" refers to the differences in scores on state or national achievement tests between various…

  19. Reliable, Economic, Efficient CO2 Heat Pump Water Heater for North America

    SciTech Connect

    Radcliff, Thomas D; Sienel, Tobias; Huff, Hans-Joachim; Thompson, Adrian; Sadegh, Payman; Olsommer, Benoit; Park, Young

    2006-12-31

    Adoption of heat pump water heating technology for commercial hot water could save up to 0.4 quads of energy and 5 million metric tons of CO2 production annually in North America, but industry perception is that this technology does not offer adequate performance or reliability and comes at too high of a cost. Development and demonstration of a CO2 heat pump water heater is proposed to reduce these barriers to adoption. Three major themes are addressed: market analysis to understand barriers to adoption, use of advanced reliability models to design optimum qualification test plans, and field testing of two phases of water heater prototypes. Market experts claim that beyond good performance, market adoption requires 'drop and forget' system reliability and a six month payback of first costs. Performance, reliability and cost targets are determined and reliability models are developed to evaluate the minimum testing required to meet reliability targets. Three phase 1 prototypes are designed and installed in the field. Based on results from these trials a product specification is developed and a second phase of five field trial units are built and installed. These eight units accumulate 11 unit-years of service including 15,650 hours and 25,242 cycles of compressor operation. Performance targets can be met. An availability of 60% is achieved and the capability to achieve >90% is demonstrated, but overall reliability is below target, with an average of 3.6 failures/unit-year on the phase 2 demonstration. Most reliability issues are shown to be common to new HVAC products, giving high confidence in mature product reliability, but the need for further work to minimize leaks and ensure reliability of the electronic expansion valve is clear. First cost is projected to be above target, leading to an expectation of 8-24 month payback when substituted for an electric water heater. Despite not meeting all targets, arguments are made that an industry leader could sufficiently

  20. Designing for Reliability and Robustness

    NASA Technical Reports Server (NTRS)

    Svetlik, Randall G.; Moore, Cherice; Williams, Antony

    2017-01-01

    Long duration spaceflight has a negative effect on the human body, and exercise countermeasures are used on-board the International Space Station (ISS) to minimize bone and muscle loss, combatting these effects. Given the importance of these hardware systems to the health of the crew, this equipment must continue to be readily available. Designing spaceflight exercise hardware to meet high reliability and availability standards has proven to be challenging throughout the time the crewmembers have been living on ISS beginning in 2000. Furthermore, restoring operational capability after a failure is clearly time-critical, but can be problematic given the challenges of troubleshooting the problem from 220 miles away. Several best-practices have been leveraged in seeking to maximize availability of these exercise systems, including designing for robustness, implementing diagnostic instrumentation, relying on user feedback, and providing ample maintenance and sparing. These factors have enhanced the reliability of hardware systems, and therefore have contributed to keeping the crewmembers healthy upon return to Earth. This paper will review the failure history for three spaceflight exercise countermeasure systems identifying lessons learned that can help improve future systems. Specifically, the Treadmill with Vibration Isolation and Stabilization System (TVIS), Cycle Ergometer with Vibration Isolation and Stabilization System (CEVIS), and the Advanced Resistive Exercise Device (ARED) will be reviewed, analyzed, and conclusions identified so as to provide guidance for improving future exercise hardware designs. These lessons learned, paired with thorough testing, offer a path towards reduced system down-time.

  1. Reliability of steam generator tubing

    SciTech Connect

    Kadokami, E.

    1997-02-01

    The author presents results on studies made of the reliability of steam generator (SG) tubing. The basis for this work is that in Japan the issue of defects in SG tubing is addressed by the approach that any detected defect should be repaired, either by plugging the tube or sleeving it. However, this leaves open the issue that there is a detection limit in practice, and what is the effect of nondetectable cracks on the performance of tubing. These studies were commissioned to look at the safety issues involved in degraded SG tubing. The program has looked at a number of different issues. First was an assessment of the penetration and opening behavior of tube flaws due to internal pressure in the tubing. They have studied: penetration behavior of the tube flaws; primary water leakage from through-wall flaws; opening behavior of through-wall flaws. In addition they have looked at the question of the reliability of tubing with flaws during normal plant operation. Also there have been studies done on the consequences of tube rupture accidents on the integrity of neighboring tubes.

  2. Space Shuttle Propulsion System Reliability

    NASA Technical Reports Server (NTRS)

    Welzyn, Ken; VanHooser, Katherine; Moore, Dennis; Wood, David

    2011-01-01

    This session includes the following sessions: (1) External Tank (ET) System Reliability and Lessons, (2) Space Shuttle Main Engine (SSME), Reliability Validated by a Million Seconds of Testing, (3) Reusable Solid Rocket Motor (RSRM) Reliability via Process Control, and (4) Solid Rocket Booster (SRB) Reliability via Acceptance and Testing.

  3. Construction of Valid and Reliable Test for Assessment of Students

    ERIC Educational Resources Information Center

    Osadebe, P. U.

    2015-01-01

    The study was carried out to construct a valid and reliable test in Economics for secondary school students. Two research questions were drawn to guide the establishment of validity and reliability for the Economics Achievement Test (EAT). It is a multiple choice objective test of five options with 100 items. A sample of 1000 students was randomly…

  4. Human Reliability Program Workshop

    SciTech Connect

    Landers, John; Rogers, Erin; Gerke, Gretchen

    2014-05-18

    A Human Reliability Program (HRP) is designed to protect national security as well as worker and public safety by continuously evaluating the reliability of those who have access to sensitive materials, facilities, and programs. Some elements of a site HRP include systematic (1) supervisory reviews, (2) medical and psychological assessments, (3) management evaluations, (4) personnel security reviews, and (4) training of HRP staff and critical positions. Over the years of implementing an HRP, the Department of Energy (DOE) has faced various challenges and overcome obstacles. During this 4-day activity, participants will examine programs that mitigate threats to nuclear security and the insider threat to include HRP, Nuclear Security Culture (NSC) Enhancement, and Employee Assistance Programs. The focus will be to develop an understanding of the need for a systematic HRP and to discuss challenges and best practices associated with mitigating the insider threat.

  5. Availability and End-to-end Reliability in Low Duty Cycle Multihop Wireless Sensor Networks.

    PubMed

    Suhonen, Jukka; Hämäläinen, Timo D; Hännikäinen, Marko

    2009-01-01

    A wireless sensor network (WSN) is an ad-hoc technology that may even consist of thousands of nodes, which necessitates autonomic, self-organizing and multihop operations. A typical WSN node is battery powered, which makes the network lifetime the primary concern. The highest energy efficiency is achieved with low duty cycle operation, however, this alone is not enough. WSNs are deployed for different uses, each requiring acceptable Quality of Service (QoS). Due to the unique characteristics of WSNs, such as dynamic wireless multihop routing and resource constraints, the legacy QoS metrics are not feasible as such. We give a new definition to measure and implement QoS in low duty cycle WSNs, namely availability and reliability. Then, we analyze the effect of duty cycling for reaching the availability and reliability. The results are obtained by simulations with ZigBee and proprietary TUTWSN protocols. Based on the results, we also propose a data forwarding algorithm suitable for resource constrained WSNs that guarantees end-to-end reliability while adding a small overhead that is relative to the packet error rate (PER). The forwarding algorithm guarantees reliability up to 30% PER.

  6. Designing reliability into accelerators

    NASA Astrophysics Data System (ADS)

    Hutton, A.

    1992-07-01

    Future accelerators will have to provide a high degree of reliability. Quality must be designed in right from the beginning and must remain a central theme throughout the project. The problem is similar to the problems facing US industry today, and examples of the successful application of quality engineering will be given. Different aspects of an accelerator project will be addressed: Concept, Design, Motivation, Management Techniques, and Fault Diagnosis. The importance of creating and maintaining a coherent team will be stressed.

  7. Reliability and testing

    NASA Technical Reports Server (NTRS)

    Auer, Werner

    1996-01-01

    Reliability and its interdependence with testing are important topics for development and manufacturing of successful products. This generally accepted fact is not only a technical statement, but must be also seen in the light of 'Human Factors.' While the background for this paper is the experience gained with electromechanical/electronic space products, including control and system considerations, it is believed that the content could be also of interest for other fields.

  8. Laser System Reliability

    DTIC Science & Technology

    1977-03-01

    NEALE CAPT. RANDALL D. GODFREY CAPT. JOHN E. ACTON HR. DAVE B. LEMMING (ASD) :,^ 19 . ••^w**** SECTION III RELIABILITY PREDICTION...Dete Exchange Program) failure rate date bank. In addition, some data have been obtained from Hughes. Rocketdyne , Garrett, and the AFWL’s APT Failure...Central Ave, Suite 306, Albuq, NM 87108 R/M Systems, Inc (Dr. K. Blemel), 10801 Lomas 81vd NE, Albuquerque, NM 87112 Rocketdyne 01 v, Rockwell

  9. Spacecraft transmitter reliability

    NASA Technical Reports Server (NTRS)

    1980-01-01

    A workshop on spacecraft transmitter reliability was held at the NASA Lewis Research Center on September 25 and 26, 1979, to discuss present knowledge and to plan future research areas. Since formal papers were not submitted, this synopsis was derived from audio tapes of the workshop. The following subjects were covered: users' experience with space transmitters; cathodes; power supplies and interfaces; and specifications and quality assurance. A panel discussion ended the workshop.

  10. Software reliability studies

    NASA Technical Reports Server (NTRS)

    Hoppa, Mary Ann; Wilson, Larry W.

    1994-01-01

    There are many software reliability models which try to predict future performance of software based on data generated by the debugging process. Our research has shown that by improving the quality of the data one can greatly improve the predictions. We are working on methodologies which control some of the randomness inherent in the standard data generation processes in order to improve the accuracy of predictions. Our contribution is twofold in that we describe an experimental methodology using a data structure called the debugging graph and apply this methodology to assess the robustness of existing models. The debugging graph is used to analyze the effects of various fault recovery orders on the predictive accuracy of several well-known software reliability algorithms. We found that, along a particular debugging path in the graph, the predictive performance of different models can vary greatly. Similarly, just because a model 'fits' a given path's data well does not guarantee that the model would perform well on a different path. Further we observed bug interactions and noted their potential effects on the predictive process. We saw that not only do different faults fail at different rates, but that those rates can be affected by the particular debugging stage at which the rates are evaluated. Based on our experiment, we conjecture that the accuracy of a reliability prediction is affected by the fault recovery order as well as by fault interaction.

  11. Illustrated structural application of universal first-order reliability method

    NASA Technical Reports Server (NTRS)

    Verderaime, V.

    1994-01-01

    The general application of the proposed first-order reliability method was achieved through the universal normalization of engineering probability distribution data. The method superimposes prevailing deterministic techniques and practices on the first-order reliability method to surmount deficiencies of the deterministic method and provide benefits of reliability techniques and predictions. A reliability design factor is derived from the reliability criterion to satisfy a specified reliability and is analogous to the deterministic safety factor. Its application is numerically illustrated on several practical structural design and verification cases with interesting results and insights. Two concepts of reliability selection criteria are suggested. Though the method was developed to support affordable structures for access to space, the method should also be applicable for most high-performance air and surface transportation systems.

  12. Reliability of high power/brightness diode lasers emitting from 790 to 980 nm

    NASA Astrophysics Data System (ADS)

    Bao, L.; Bai, J.; Price, K.; Devito, M.; Grimshaw, M.; Dong, W.; Guan, X.; Zhang, S.; Zhou, H.; Bruce, K.; Dawson, D.; Kanskar, M.; Martinsen, R.; Haden, J.

    2013-02-01

    This paper presents recent progress in the development of high power single emitter laser diodes from 790 nm to 980 nm for reliable use in industrial and pumping applications. High performance has been demonstrated on diode lasers from 790 nm to 980 nm, with corresponding peak efficiency ~65%. Reliability has been fully demonstrated on high power diode lasers of 3.8 mm laser cavity at 3 major wavelengths. We report on the correlation between photon-energy (wavelength) and device failure modes (reliability). A newly released laser design demonstrates diode lasers with 5.0 mm laser cavity at 915-980 nm and 790 nm, with efficiency that matches the values achieved with 3.8 mm cavity length. 915-980 nm single emitters with 5.0 mm laser cavity were especially designed for high power and high brightness applications and can be reliably operated at 12 W to 18 W. These pumps have been incorporated into nLIGHT's newly developed fiber coupled pump module, elementTM. Ongoing highly accelerated diode life-tests have accumulated over 200,000 raw device hours, with extremely low failure rate observed to date. High reliability has also been demonstrated from multiple accelerated module-level lifetests.

  13. A Report on Simulation-Driven Reliability and Failure Analysis of Large-Scale Storage Systems

    SciTech Connect

    Wan, Lipeng; Wang, Feiyi; Oral, H. Sarp; Vazhkudai, Sudharshan S.; Cao, Qing

    2014-11-01

    High-performance computing (HPC) storage systems provide data availability and reliability using various hardware and software fault tolerance techniques. Usually, reliability and availability are calculated at the subsystem or component level using limited metrics such as, mean time to failure (MTTF) or mean time to data loss (MTTDL). This often means settling on simple and disconnected failure models (such as exponential failure rate) to achieve tractable and close-formed solutions. However, such models have been shown to be insufficient in assessing end-to-end storage system reliability and availability. We propose a generic simulation framework aimed at analyzing the reliability and availability of storage systems at scale, and investigating what-if scenarios. The framework is designed for an end-to-end storage system, accommodating the various components and subsystems, their interconnections, failure patterns and propagation, and performs dependency analysis to capture a wide-range of failure cases. We evaluate the framework against a large-scale storage system that is in production and analyze its failure projections toward and beyond the end of lifecycle. We also examine the potential operational impact by studying how different types of components affect the overall system reliability and availability, and present the preliminary results

  14. Photovoltaic-Reliability R&D Toward a Solar-Powered World (Presentation)

    SciTech Connect

    Kurtz, S.; Granata, J.

    2009-08-01

    Presentation about the importance of continued progress toward low-cost, high-reliability, and high-performance PV systems. High reliability is an essential element in achieving low-cost solar electricity.

  15. Reliability evaluation methodology for NASA applications

    NASA Technical Reports Server (NTRS)

    Taneja, Vidya S.

    1992-01-01

    Liquid rocket engine technology has been characterized by the development of complex systems containing large number of subsystems, components, and parts. The trend to even larger and more complex system is continuing. The liquid rocket engineers have been focusing mainly on performance driven designs to increase payload delivery of a launch vehicle for a given mission. In otherwords, although the failure of a single inexpensive part or component may cause the failure of the system, reliability in general has not been considered as one of the system parameters like cost or performance. Up till now, quantification of reliability has not been a consideration during system design and development in the liquid rocket industry. Engineers and managers have long been aware of the fact that the reliability of the system increases during development, but no serious attempts have been made to quantify reliability. As a result, a method to quantify reliability during design and development is needed. This includes application of probabilistic models which utilize both engineering analysis and test data. Classical methods require the use of operating data for reliability demonstration. In contrast, the method described in this paper is based on similarity, analysis, and testing combined with Bayesian statistical analysis.

  16. 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

  17. Methodology for making environmental as low as reasonably achievable (ALARA) determinations

    SciTech Connect

    Brown, R.C.; Speer, D.R.

    1982-01-01

    An overall evaluation concept for use in making differential cost-benefit analyses in environmental as low as reasonably achievable (ALARA) determinations is being implemented by Rockwell Hanford Operations. This evaluation includes consideration of seven categories: (1) capital costs; (2) operating costs; (3) state of the art; (4) safety; (5) accident or upset consequences; (6) reliability, operability, and maintainability; and (7) decommissionability. Appropriate weighting factors for each of these categories are under development so that ALARA determinations can be made by comparing scores of alternative proposals for facility design, operations, and upgrade. This method of evaluation circumvents the traditional basis of a stated monetary sum per person-rem of dose commitment. This alternative was generated by advice from legal counsel who advised against formally pursuing this avenue of approach to ALARA for environmental and occupational dose commitments.

  18. Optimal PGU operation strategy in CHP systems

    NASA Astrophysics Data System (ADS)

    Yun, Kyungtae

    Traditional power plants only utilize about 30 percent of the primary energy that they consume, and the rest of the energy is usually wasted in the process of generating or transmitting electricity. On-site and near-site power generation has been considered by business, labor, and environmental groups to improve the efficiency and the reliability of power generation. Combined heat and power (CHP) systems are a promising alternative to traditional power plants because of the high efficiency and low CO2 emission achieved by recovering waste thermal energy produced during power generation. A CHP operational algorithm designed to optimize operational costs must be relatively simple to implement in practice such as to minimize the computational requirements from the hardware to be installed. This dissertation focuses on the following aspects pertaining the design of a practical CHP operational algorithm designed to minimize the operational costs: (a) real-time CHP operational strategy using a hierarchical optimization algorithm; (b) analytic solutions for cost-optimal power generation unit operation in CHP Systems; (c) modeling of reciprocating internal combustion engines for power generation and heat recovery; (d) an easy to implement, effective, and reliable hourly building load prediction algorithm.

  19. Reliability optimization of a surveillance radar

    NASA Astrophysics Data System (ADS)

    Bajakian, A.; Cawood, G.; Kott, M.; Stiebohr, K.

    The PAVE FAWS phase-array search/track radar for submarine launched ballistic missile target detection and characterization supplies the USAF SPACETRACK with satellite detection, tracking, and identification. The USAF proposal specifies MTBF of 100 hr and an operational availability of 0.98 which can be accomplished by a system architecture which optimizes reliability, availability, and easy maintenance. The architecture is designed for hardware redundancy, fault tolerance in antenna electronics allowing degradation within the specification, high reliability screened and qualified parts, and automated diagnostics.

  20. Gearbox Reliability Collaborative Update: A Brief (Presentation)

    SciTech Connect

    Sheng, S.; Keller, J.; McDade, M.

    2012-01-01

    This presentation is an update on the Gearbox Reliability Collaborative (GRC) for the AWEA Wind Project Operations, Maintenance & Reliability Seminar. GRC accomplishments are: (1) Failure database software deployed - partners see business value for themselves and customers; (2) Designed, built, instrumented, and tested two gearboxes - (a) Generated unprecedented public domain test data from both field testing and dynamometer testing, (b) Different responses from 'identical' gearboxes, (c) Demonstrated importance of non-torque loading and modeling approach; and (3) Active collaborative, with wide industry support, leveraging DOE funding - Modeling round robin and Condition Monitoring round robin.

  1. Microcircuit Device Reliability. Digital Failure Rate Data

    DTIC Science & Technology

    1981-01-01

    dfc ^MlM "" ■ ’’ •""" DIGITAL DEVICE DATA VARIOUS TTL t MANUFACTURER OPERATIONAL TYPE RELIABILITt ANALYSIS...Analysis Center I $ ^: io Microcircuit Device Reliability DIGITAL FAILURE RATE DATA t - D D Summer 1981 Prepared by: Reliability Analysis...Approved for Public Release, Distribution Unlimited .. .11 ■■’■’■’■.■^"■i;>;->k:.v.v^-:.-.,-,->■’^ ■.■»[ >** T *»,*-’,>;’ * ’^ ■ t , ■ A

  2. Ultra Reliable Closed Loop Life Support for Long Space Missions

    NASA Technical Reports Server (NTRS)

    Jones, Harry W.; Ewert, Michael K.

    2010-01-01

    Spacecraft human life support systems can achieve ultra reliability by providing sufficient spares to replace all failed components. The additional mass of spares for ultra reliability is approximately equal to the original system mass, provided that the original system reliability is not too low. Acceptable reliability can be achieved for the Space Shuttle and Space Station by preventive maintenance and by replacing failed units. However, on-demand maintenance and repair requires a logistics supply chain in place to provide the needed spares. In contrast, a Mars or other long space mission must take along all the needed spares, since resupply is not possible. Long missions must achieve ultra reliability, a very low failure rate per hour, since they will take years rather than weeks and cannot be cut short if a failure occurs. Also, distant missions have a much higher mass launch cost per kilogram than near-Earth missions. Achieving ultra reliable spacecraft life support systems with acceptable mass will require a well-planned and extensive development effort. Analysis must determine the reliability requirement and allocate it to subsystems and components. Ultra reliability requires reducing the intrinsic failure causes, providing spares to replace failed components and having "graceful" failure modes. Technologies, components, and materials must be selected and designed for high reliability. Long duration testing is needed to confirm very low failure rates. Systems design should segregate the failure causes in the smallest, most easily replaceable parts. The system must be designed, developed, integrated, and tested with system reliability in mind. Maintenance and reparability of failed units must not add to the probability of failure. The overall system must be tested sufficiently to identify any design errors. A program to develop ultra reliable space life support systems with acceptable mass should start soon since it must be a long term effort.

  3. Experts’ Opinions on the Reliability Gap and Some Practical Guidelines on Reliability Growth

    DTIC Science & Technology

    1988-09-01

    and found the ratio of the disparity to range 2 from 2.1:1 to 9.1:1 (38:231). Furthermore, Montemayor (54) studied the reliability gap between...Production, 17 October 1986. 54. Montemayor , A. J. "Achieved versus Predicted Mean-Time-Between-Failures (M.TBF)." The Boeing Company, D194-300341, March

  4. Development of a Pattern Recognition Methodology for Determining Operationally Optimal Heat Balance Instrumentation Calibration Schedules

    SciTech Connect

    Kurt Beran; John Christenson; Dragos Nica; Kenny Gross

    2002-12-15

    The goal of the project is to enable plant operators to detect with high sensitivity and reliability the onset of decalibration drifts in all of the instrumentation used as input to the reactor heat balance calculations. To achieve this objective, the collaborators developed and implemented at DBNPS an extension of the Multivariate State Estimation Technique (MSET) pattern recognition methodology pioneered by ANAL. The extension was implemented during the second phase of the project and fully achieved the project goal.

  5. The 747 primary flight control systems reliability and maintenance study

    NASA Technical Reports Server (NTRS)

    1979-01-01

    The major operational characteristics of the 747 Primary Flight Control Systems (PFCS) are described. Results of reliability analysis for separate control functions are presented. The analysis makes use of a NASA computer program which calculates reliability of redundant systems. Costs for maintaining the 747 PFCS in airline service are assessed. The reliabilities and cost will provide a baseline for use in trade studies of future flight control system design.

  6. Algebraic Methods Applied to Network Reliability Problems. Revision.

    DTIC Science & Technology

    1986-09-01

    RD-RIBs 38? ALGEBRAIC METHODS APPLIED TO NETHORK RELIABILITY 1/1 PROBLEMS REVISIOU(U) CLEMSON UNIV SC DEPT OF MATEMATICAL SCIENCES D R SHIER ET AL...class of directed networks, Oper. Res., 32 (1984), pp. 493-515. -2 " 16 [3] A. AGRAWAL AND A. SATYANARAYANA, Network reliability analysis using 2...Networks, 13 (1983), pp. 107-120. [20] A. SATYANARAYANA AND A. PRABHAKAR, A new topological formula and rapid algorithm for reliability analysis of complex

  7. CR reliability testing

    NASA Astrophysics Data System (ADS)

    Honeyman-Buck, Janice C.; Rill, Lynn; Frost, Meryll M.; Staab, Edward V.

    1998-07-01

    The purpose of this work was to develop a method for systematically testing the reliability of a CR system under realistic daily loads in a non-clinical environment prior to its clinical adoption. Once digital imaging replaces film, it will be very difficult to revert back should the digital system become unreliable. Prior to the beginning of the test, a formal evaluation was performed to set the benchmarks for performance and functionality. A formal protocol was established that included all the 62 imaging plates in the inventory for each 24-hour period in the study. Imaging plates were exposed using different combinations of collimation, orientation, and SID. Anthropomorphic phantoms were used to acquire images of different sizes. Each combination was chosen randomly to simulate the differences that could occur in clinical practice. The tests were performed over a wide range of times with batches of plates processed to simulate the temporal constraints required by the nature of portable radiographs taken in the Intensive Care Unit (ICU). Current patient demographics were used for the test studies so automatic routing algorithms could be tested. During the test, only three minor reliability problems occurred, two of which were not directly related to the CR unit. One plate was discovered to cause a segmentation error that essentially reduced the image to only black and white with no gray levels. This plate was removed from the inventory to be replaced. Another problem was a PACS routing problem that occurred when the DICOM server with which the CR was communicating had a problem with disk space. The final problem was a network printing failure to the laser cameras. Although the units passed the reliability test, problems with interfacing to workstations were discovered. The two issues that were identified were the interpretation of what constitutes a study for CR and the construction of the look-up table for a proper gray scale display.

  8. Testing of reliability - Analysis tools

    NASA Technical Reports Server (NTRS)

    Hayhurst, Kelly J.

    1989-01-01

    An outline is presented of issues raised in verifying the accuracy of reliability analysis tools. State-of-the-art reliability analysis tools implement various decomposition, aggregation, and estimation techniques to compute the reliability of a diversity of complex fault-tolerant computer systems. However, no formal methodology has been formulated for validating the reliability estimates produced by these tools. The author presents three states of testing that can be performed on most reliability analysis tools to effectively increase confidence in a tool. These testing stages were applied to the SURE (semi-Markov Unreliability Range Evaluator) reliability analysis tool, and the results of the testing are discussed.

  9. Reliable inverter systems

    NASA Technical Reports Server (NTRS)

    Nagano, S.

    1979-01-01

    Base driver with common-load-current feedback protects paralleled inverter systems from open or short circuits. Circuit eliminates total system oscillation that can occur in conventional inverters because of open circuit in primary transformer winding. Common feedback signal produced by functioning modules forces operating frequency of failed module to coincide with clock drive so module resumes normal operating frequency in spite of open circuit.

  10. Schoolbook Texts: Behavioral Achievement Priming in Math and Language.

    PubMed

    Engeser, Stefan; Baumann, Nicola; Baum, Ingrid

    2016-01-01

    Prior research found reliable and considerably strong effects of semantic achievement primes on subsequent performance. In order to simulate a more natural priming condition to better understand the practical relevance of semantic achievement priming effects, running texts of schoolbook excerpts with and without achievement primes were used as priming stimuli. Additionally, we manipulated the achievement context; some subjects received no feedback about their achievement and others received feedback according to a social or individual reference norm. As expected, we found a reliable (albeit small) positive behavioral priming effect of semantic achievement primes on achievement in math (Experiment 1) and language tasks (Experiment 2). Feedback moderated the behavioral priming effect less consistently than we expected. The implication that achievement primes in schoolbooks can foster performance is discussed along with general theoretical implications.

  11. Schoolbook Texts: Behavioral Achievement Priming in Math and Language

    PubMed Central

    Engeser, Stefan; Baumann, Nicola; Baum, Ingrid

    2016-01-01

    Prior research found reliable and considerably strong effects of semantic achievement primes on subsequent performance. In order to simulate a more natural priming condition to better understand the practical relevance of semantic achievement priming effects, running texts of schoolbook excerpts with and without achievement primes were used as priming stimuli. Additionally, we manipulated the achievement context; some subjects received no feedback about their achievement and others received feedback according to a social or individual reference norm. As expected, we found a reliable (albeit small) positive behavioral priming effect of semantic achievement primes on achievement in math (Experiment 1) and language tasks (Experiment 2). Feedback moderated the behavioral priming effect less consistently than we expected. The implication that achievement primes in schoolbooks can foster performance is discussed along with general theoretical implications. PMID:26938446

  12. Natural Circulation in Water Cooled Nuclear Power Plants Phenomena, models, and methodology for system reliability assessments

    SciTech Connect

    Jose Reyes

    2005-02-14

    In recent years it has been recognized that the application of passive safety systems (i.e., those whose operation takes advantage of natural forces such as convection and gravity), can contribute to simplification and potentially to improved economics of new nuclear power plant designs. In 1991 the IAEA Conference on ''The Safety of Nuclear Power: Strategy for the Future'' noted that for new plants the use of passive safety features is a desirable method of achieving simplification and increasing the reliability of the performance of essential safety functions, and should be used wherever appropriate''.

  13. Manufacturing process controls for high reliability carbon filament-wound seamless-aluminum-lined composite pressure vessels

    NASA Astrophysics Data System (ADS)

    Braun, C. A.; Haddock, R. C.

    1992-07-01

    An account is given of the manufacturing, inspection, and test-process variables associated with the production of carbon filament-wound/epoxy-matrix, seamless aluminum-lined pressure vessels, which have achieved operating pressures of the order of 10,000 psi and burst-to-operating safety factors of as low as 1.5-1.0. Attention is given to the process controls that are needed to reach current reliability requirements. Attention is given to liner surface preparation, age sensitivity, and the dangers of exposure to heat and stress.

  14. Self Regulated Learning of High Achievers

    ERIC Educational Resources Information Center

    Rathod, Ami

    2010-01-01

    The study was conducted on high achievers of Senior Secondary school. Main objectives were to identify the self regulated learners among the high achievers, to find out dominant components and characteristics operative in self regulated learners and to compare self regulated learning of learners with respect to their subject (science and non…

  15. Integrated circuit reliability testing

    NASA Technical Reports Server (NTRS)

    Buehler, Martin G. (Inventor); Sayah, Hoshyar R. (Inventor)

    1990-01-01

    A technique is described for use in determining the reliability of microscopic conductors deposited on an uneven surface of an integrated circuit device. A wafer containing integrated circuit chips is formed with a test area having regions of different heights. At the time the conductors are formed on the chip areas of the wafer, an elongated serpentine assay conductor is deposited on the test area so the assay conductor extends over multiple steps between regions of different heights. Also, a first test conductor is deposited in the test area upon a uniform region of first height, and a second test conductor is deposited in the test area upon a uniform region of second height. The occurrence of high resistances at the steps between regions of different height is indicated by deriving the measured length of the serpentine conductor using the resistance measured between the ends of the serpentine conductor, and comparing that to the design length of the serpentine conductor. The percentage by which the measured length exceeds the design length, at which the integrated circuit will be discarded, depends on the required reliability of the integrated circuit.

  16. Integrated circuit reliability testing

    NASA Technical Reports Server (NTRS)

    Buehler, Martin G. (Inventor); Sayah, Hoshyar R. (Inventor)

    1988-01-01

    A technique is described for use in determining the reliability of microscopic conductors deposited on an uneven surface of an integrated circuit device. A wafer containing integrated circuit chips is formed with a test area having regions of different heights. At the time the conductors are formed on the chip areas of the wafer, an elongated serpentine assay conductor is deposited on the test area so the assay conductor extends over multiple steps between regions of different heights. Also, a first test conductor is deposited in the test area upon a uniform region of first height, and a second test conductor is deposited in the test area upon a uniform region of second height. The occurrence of high resistances at the steps between regions of different height is indicated by deriving the measured length of the serpentine conductor using the resistance measured between the ends of the serpentine conductor, and comparing that to the design length of the serpentine conductor. The percentage by which the measured length exceeds the design length, at which the integrated circuit will be discarded, depends on the required reliability of the integrated circuit.

  17. The Reliability of Neurons

    PubMed Central

    Bullock, Theodore Holmes

    1970-01-01

    The prevalent probabilistic view is virtually untestable; it remains a plausible belief. The cases usually cited can not be taken as evidence for it. Several grounds for this conclusion are developed. Three issues are distinguished in an attempt to clarify a murky debate: (a) the utility of probabilistic methods in data reduction, (b) the value of models that assume indeterminacy, and (c) the validity of the inference that the nervous system is largely indeterministic at the neuronal level. No exception is taken to the first two; the second is a private heuristic question. The third is the issue to which the assertion in the first two sentences is addressed. Of the two kinds of uncertainty, statistical mechanical (= practical unpredictability) as in a gas, and Heisenbergian indeterminancy, the first certainly exists, the second is moot at the neuronal level. It would contribute to discussion to recognize that neurons perform with a degree of reliability. Although unreliability is difficult to establish, to say nothing of measure, evidence that some neurons have a high degree of reliability, in both connections and activity is increasing greatly. An example is given from sternarchine electric fish. PMID:5462670

  18. Reliable Entanglement Verification

    NASA Astrophysics Data System (ADS)

    Arrazola, Juan; Gittsovich, Oleg; Donohue, John; Lavoie, Jonathan; Resch, Kevin; Lütkenhaus, Norbert

    2013-05-01

    Entanglement plays a central role in quantum protocols. It is therefore important to be able to verify the presence of entanglement in physical systems from experimental data. In the evaluation of these data, the proper treatment of statistical effects requires special attention, as one can never claim to have verified the presence of entanglement with certainty. Recently increased attention has been paid to the development of proper frameworks to pose and to answer these type of questions. In this work, we apply recent results by Christandl and Renner on reliable quantum state tomography to construct a reliable entanglement verification procedure based on the concept of confidence regions. The statements made do not require the specification of a prior distribution nor the assumption of an independent and identically distributed (i.i.d.) source of states. Moreover, we develop efficient numerical tools that are necessary to employ this approach in practice, rendering the procedure ready to be employed in current experiments. We demonstrate this fact by analyzing the data of an experiment where photonic entangled two-photon states were generated and whose entanglement is verified with the use of an accessible nonlinear witness.

  19. 14 CFR 91.1415 - CAMP: Mechanical reliability reports.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... 14 Aeronautics and Space 2 2011-01-01 2011-01-01 false CAMP: Mechanical reliability reports. 91.1415 Section 91.1415 Aeronautics and Space FEDERAL AVIATION ADMINISTRATION, DEPARTMENT OF... Ownership Operations Program Management § 91.1415 CAMP: Mechanical reliability reports. (a) Each...

  20. 14 CFR 91.1415 - CAMP: Mechanical reliability reports.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... 14 Aeronautics and Space 2 2012-01-01 2012-01-01 false CAMP: Mechanical reliability reports. 91.1415 Section 91.1415 Aeronautics and Space FEDERAL AVIATION ADMINISTRATION, DEPARTMENT OF... Ownership Operations Program Management § 91.1415 CAMP: Mechanical reliability reports. (a) Each...

  1. 14 CFR 91.1415 - CAMP: Mechanical reliability reports.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... 14 Aeronautics and Space 2 2013-01-01 2013-01-01 false CAMP: Mechanical reliability reports. 91.1415 Section 91.1415 Aeronautics and Space FEDERAL AVIATION ADMINISTRATION, DEPARTMENT OF... Ownership Operations Program Management § 91.1415 CAMP: Mechanical reliability reports. (a) Each...

  2. 'No delays achiever'.

    PubMed

    2007-05-01

    The latest version of the NHS Institute for Innovation and Improvement's 'no delays achiever', a web based tool created to help NHS organisations achieve the 18-week target for GP referrals to first treatment, is available at www.nodelaysachiever.nhs.uk.

  3. Vicarious Achievement Orientation.

    ERIC Educational Resources Information Center

    Leavitt, Harold J.; And Others

    This study tests hypotheses about achievement orientation, particularly vicarious achievement. Undergraduate students (N=437) completed multiple-choice questionnaires, indicating likely responses of one person to the success of another. The sex of succeeder and observer, closeness of relationship, and setting (medical school or graduate school of…

  4. Heritability of Creative Achievement

    ERIC Educational Resources Information Center

    Piffer, Davide; Hur, Yoon-Mi

    2014-01-01

    Although creative achievement is a subject of much attention to lay people, the origin of individual differences in creative accomplishments remain poorly understood. This study examined genetic and environmental influences on creative achievement in an adult sample of 338 twins (mean age = 26.3 years; SD = 6.6 years). Twins completed the Creative…

  5. Confronting the Achievement Gap

    ERIC Educational Resources Information Center

    Gardner, David

    2007-01-01

    This article talks about the large achievement gap between children of color and their white peers. The reasons for the achievement gap are varied. First, many urban minorities come from a background of poverty. One of the detrimental effects of growing up in poverty is receiving inadequate nourishment at a time when bodies and brains are rapidly…

  6. Achievement-Based Resourcing.

    ERIC Educational Resources Information Center

    Fletcher, Mike; And Others

    1992-01-01

    This collection of seven articles examines achievement-based resourcing (ABR), the concept that the funding of educational institutions should be linked to their success in promoting student achievement, with a focus on the application of ABR to postsecondary education in the United Kingdom. The articles include: (1) "Introduction" (Mick…

  7. States Address Achievement Gaps.

    ERIC Educational Resources Information Center

    Christie, Kathy

    2002-01-01

    Summarizes 2 state initiatives to address the achievement gap: North Carolina's report by the Advisory Commission on Raising Achievement and Closing Gaps, containing an 11-point strategy, and Kentucky's legislation putting in place 10 specific processes. The North Carolina report is available at www.dpi.state.nc.us.closingthegap; Kentucky's…

  8. Selected reliability studies for the NERVA program

    NASA Technical Reports Server (NTRS)

    Hoover, S. V.; Murphy, R. J.; Nowak, W. B.; Sexton, R. W.

    1974-01-01

    An investigation was made into certain methods of reliability analysis that are particularly suitable for complex mechanisms or systems in which there are many interactions. The methods developed were intended to assist in the design of such mechanisms, especially for analysis of failure sensitivity to parameter variations and for estimating reliability where extensive and meaningful life testing is not feasible. The system is modeled by a network of interconnected nodes. Each node is a state or mode of operation, or is an input or output node, and the branches are interactions. The network, with its probabilistic and time-dependent paths is also analyzed for reliability and failure modes by a Monte Carlo, computerized simulation of system performance.

  9. Program for computer aided reliability estimation

    NASA Technical Reports Server (NTRS)

    Mathur, F. P. (Inventor)

    1972-01-01

    A computer program for estimating the reliability of self-repair and fault-tolerant systems with respect to selected system and mission parameters is presented. The computer program is capable of operation in an interactive conversational mode as well as in a batch mode and is characterized by maintenance of several general equations representative of basic redundancy schemes in an equation repository. Selected reliability functions applicable to any mathematical model formulated with the general equations, used singly or in combination with each other, are separately stored. One or more system and/or mission parameters may be designated as a variable. Data in the form of values for selected reliability functions is generated in a tabular or graphic format for each formulated model.

  10. Experiences with Two Reliability Data Collection Efforts (Presentation)

    SciTech Connect

    Sheng, S.; Lantz, E.

    2013-08-01

    This presentation, given by NREL at the Wind Reliability Experts Meeting in Albuquerque, New Mexico, outlines the causes of wind plant operational expenditures and gearbox failures and describes NREL's efforts to create a gearbox failure database.

  11. Allocating SMART Reliability and Maintainability Goals to NASA Ground Systems

    NASA Technical Reports Server (NTRS)

    Gillespie, Amanda; Monaghan, Mark

    2013-01-01

    This paper will describe the methodology used to allocate Reliability and Maintainability (R&M) goals to Ground Systems Development and Operations (GSDO) subsystems currently being designed or upgraded.

  12. Real Time Grid Reliability Management 2005

    SciTech Connect

    Eto, Joe; Eto, Joe; Lesieutre, Bernard; Lewis, Nancy Jo; Parashar, Manu

    2008-07-07

    The increased need to manage California?s electricity grid in real time is a result of the ongoing transition from a system operated by vertically-integrated utilities serving native loads to one operated by an independent system operator supporting competitive energy markets. During this transition period, the traditional approach to reliability management -- construction of new transmission lines -- has not been pursued due to unresolved issues related to the financing and recovery of transmission project costs. In the absence of investments in new transmission infrastructure, the best strategy for managing reliability is to equip system operators with better real-time information about actual operating margins so that they can better understand and manage the risk of operating closer to the edge. A companion strategy is to address known deficiencies in offline modeling tools that are needed to ground the use of improved real-time tools. This project: (1) developed and conducted first-ever demonstrations of two prototype real-time software tools for voltage security assessment and phasor monitoring; and (2) prepared a scoping study on improving load and generator response models. Additional funding through two separate subsequent work authorizations has already been provided to build upon the work initiated in this project.

  13. Multi-core fiber technology for highly reliable optical network in access areas

    NASA Astrophysics Data System (ADS)

    Tanaka, Ken-ichi; Lee, Yong; Nomoto, Etsuko; Arimoto, Hideo; Sugawara, Toshiki

    2015-03-01

    A failure recovery system utilizing a multi-core fiber (MCF) link with field programmable gate array-based optical switch units was developed to achieve high capacity and highly reliable optical networks in access areas. We describe the novel MCF link based on a multi-ring structure and a protection scheme to prevent link failures. Fan-in/ -out devices and connectors are also presented to demonstrate the development status of the MCF connection technology for the link. We demonstrated path recovery by switching operation within a sufficiently short time, which is required by ITU-T. The selection of a protecting path as a failure working path was also optimized as the minimum passage of units for low loss transmission. The results we obtained indicate that our proposed link has potential for the network design of highly reliable network topologies in access areas such as data centers, systems in business areas, and fiber to the home systems in residential areas.

  14. Achievability for telerobotic systems

    NASA Astrophysics Data System (ADS)

    Kress, Reid L.; Draper, John V.; Hamel, William R.

    2001-02-01

    Methods are needed to improve the capabilities of autonomous robots to perform tasks that are difficult for contemporary robots, and to identify those tasks that robots cannot perform. Additionally, in the realm of remote handling, methods are needed to assess which tasks and/or subtasks are candidates for automation. We are developing a new approach to understanding the capability of autonomous robotic systems. This approach uses formalized methods for determining the achievability of tasks for robots, that is, the likelihood that an autonomous robot or telerobot can successfully complete a particular task. Any autonomous system may be represented in achievability space by the volume describing that system's capabilities within the 3-axis space delineated by perception, cognition, and action. This volume may be thought of as a probability density with achievability decreasing as the distance from the centroid of the volume increases. Similarly, any task may be represented within achievability space. However, as tasks have more finite requirements for perception, cognition, and action, each may be represented as a point (or, more accurately, as a small sphere) within achievability space. Analysis of achievability can serve to identify, a priori, the survivability of robotic systems and the likelihood of mission success; it can be used to plan a mission or portions of a mission; it can be used to modify a mission plan to accommodate unpredicted occurrences; it can also serve to identify needs for modifications to robotic systems or tasks to improve achievability. .

  15. Testing for PV Reliability (Presentation)

    SciTech Connect

    Kurtz, S.; Bansal, S.

    2014-09-01

    The DOE SUNSHOT workshop is seeking input from the community about PV reliability and how the DOE might address gaps in understanding. This presentation describes the types of testing that are needed for PV reliability and introduces a discussion to identify gaps in our understanding of PV reliability testing.

  16. Making Reliability Arguments in Classrooms

    ERIC Educational Resources Information Center

    Parkes, Jay; Giron, Tilia

    2006-01-01

    Reliability methodology needs to evolve as validity has done into an argument supported by theory and empirical evidence. Nowhere is the inadequacy of current methods more visible than in classroom assessment. Reliability arguments would also permit additional methodologies for evidencing reliability in classrooms. It would liberalize methodology…

  17. Reliability of microcantilevers in liquid environments

    NASA Astrophysics Data System (ADS)

    Ali, S. M.; Mantell, Susan C.; Longmire, Ellen K.

    2006-01-01

    Reliable operation of MEMS in liquid environments is an important design requirement for numerous MEMS devices in chemical, pharmaceutical, biomedical, consumer product, and defense industries. In this paper, reliability and long-term performance of microcantilevers in liquid environments is investigated. Single crystal silicon microcantilevers are subjected to long-term cyclic actuation (~10 8 -10 9 cycles) in enclosures filled with two different liquids- de-ionized water and saline solution. Additionally, silicon microcantilevers are actuated in air to enable comparison of experimental data in air and liquids. The microcantilevers have an electroplated Permalloy layer and are magnetically actuated. The resonance frequency of the microcantilevers is periodically monitored to track changes in stiffness and mechanical performance. The microcantilevers are subjected to peak stresses ranging from 0-10 MPa, which are typical for MEMS applications like AFM tips, and resonating sensors. Since the peak stresses are small compared to the tensile strength of silicon (1-3 GPa), complete structural fatigue failure is neither expected nor observed. However, operational failures characterized by a gradual decrease in resonance frequency of the microcantilevers are observed in saline solution. Changes in resonance frequency of microcantilevers actuated in air and water were negligible to within the limits of experimental accuracy. These results demonstrate that an understanding of MEMS reliability in air cannot necessarily be extended to explain and predict device reliability in liquid environments.

  18. Discrete Reliability Projection

    DTIC Science & Technology

    2014-12-01

    Defense, Handbook MIL - HDBK -189C, 2011 Hall, J. B., Methodology for Evaluating Reliability Growth Programs of Discrete Systems, Ph.D. thesis, University...pk,i ] · [ 1− (1− θ̆k) · ( N k · T )]k−m , (2.13) 5 2 Hall’s Model where m is the number of observed failure modes and d∗i estimates di (either based...Mode Failures FEF Ni d ∗ i 1 1 0.95 2 1 0.70 3 1 0.90 4 1 0.90 5 4 0.95 6 2 0.70 7 1 0.80 Using equations 2.1 and 2.2 we can calculate the failure

  19. Reliability of Radioisotope Stirling Convertor Linear Alternator

    NASA Technical Reports Server (NTRS)

    Shah, Ashwin; Korovaichuk, Igor; Geng, Steven M.; Schreiber, Jeffrey G.

    2006-01-01

    Onboard radioisotope power systems being developed and planned for NASA s deep-space missions would require reliable design lifetimes of up to 14 years. Critical components and materials of Stirling convertors have been undergoing extensive testing and evaluation in support of a reliable performance for the specified life span. Of significant importance to the successful development of the Stirling convertor is the design of a lightweight and highly efficient linear alternator. Alternator performance could vary due to small deviations in the permanent magnet properties, operating temperature, and component geometries. Durability prediction and reliability of the alternator may be affected by these deviations from nominal design conditions. Therefore, it is important to evaluate the effect of these uncertainties in predicting the reliability of the linear alternator performance. This paper presents a study in which a reliability-based methodology is used to assess alternator performance. The response surface characterizing the induced open-circuit voltage performance is constructed using 3-D finite element magnetic analysis. Fast probability integration method is used to determine the probability of the desired performance and its sensitivity to the alternator design parameters.

  20. NASA Applications and Lessons Learned in Reliability Engineering

    NASA Technical Reports Server (NTRS)

    Safie, Fayssal M.; Fuller, Raymond P.

    2011-01-01

    Since the Shuttle Challenger accident in 1986, communities across NASA have been developing and extensively using quantitative reliability and risk assessment methods in their decision making process. This paper discusses several reliability engineering applications that NASA has used over the year to support the design, development, and operation of critical space flight hardware. Specifically, the paper discusses several reliability engineering applications used by NASA in areas such as risk management, inspection policies, components upgrades, reliability growth, integrated failure analysis, and physics based probabilistic engineering analysis. In each of these areas, the paper provides a brief discussion of a case study to demonstrate the value added and the criticality of reliability engineering in supporting NASA project and program decisions to fly safely. Examples of these case studies discussed are reliability based life limit extension of Shuttle Space Main Engine (SSME) hardware, Reliability based inspection policies for Auxiliary Power Unit (APU) turbine disc, probabilistic structural engineering analysis for reliability prediction of the SSME alternate turbo-pump development, impact of ET foam reliability on the Space Shuttle System risk, and reliability based Space Shuttle upgrade for safety. Special attention is given in this paper to the physics based probabilistic engineering analysis applications and their critical role in evaluating the reliability of NASA development hardware including their potential use in a research and technology development environment.

  1. 78 FR 14783 - Citizens Energy Task Force, Save Our Unique Lands (Complainants) v. Midwest Reliability...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-03-07

    ... Reliability Organization, Midwest Independent Transmission System Operator, Inc., Xcel Energy, Inc., Great River Energy, Dairyland Power Cooperative, Wisconsin Public Power Inc., (Respondents); Notice of... grid were not considered, and that instead of improving the reliability of the system, it...

  2. Operation Poorman

    SciTech Connect

    Pruvost, N.; Tsitouras, J.

    1981-03-18

    The objectives of Operation Poorman were to design and build a portable seismic system and to set up and use this system in a cold-weather environment. The equipment design uses current technology to achieve a low-power, lightweight system that is configured into three modules. The system was deployed in Alaska during wintertime, and the results provide a basis for specifying a mission-ready seismic verification system.

  3. 76 FR 23801 - North American Electric Reliability Corporation; Order Approving Reliability Standard

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-04-28

    ... cost of Reliability Standard EOP-008-1 should not present a significant operating cost to a substantial...-Requirement one of four violation severity levels--low, moderate, high, and severe--as measurements for the... functionality (one-time). Total one-time 7,540 Total recurring 1,720 Total 9,260 Information Collection...

  4. Culture and Achievement Motivation

    ERIC Educational Resources Information Center

    Maehr, Martin L.

    1974-01-01

    A framework is suggested for the cross-cultural study of motivation that stresses the importance of contextual conditions in eliciting achievement motivation and emphasizes cultural relativity in the definition of the concept. (EH)

  5. Achieving Salary Equity

    ERIC Educational Resources Information Center

    Nevill, Dorothy D.

    1975-01-01

    Three techniques are outlined for use by higher education institutions to achieve salary equity: salary prediction (using various statistical procedures), counterparting (comparing salaries of persons of similar rank), and grievance procedures. (JT)

  6. Modified aerospace reliability and quality assurance method for wind turbines

    NASA Technical Reports Server (NTRS)

    Klein, W. E.

    1980-01-01

    The safety, reliability, and quality assurance (SR&QA) approach developed for the first large wind turbine generator project is described. The SR&QA approach was used to assure that the machine would not be hazardous to the public or operating personnel, would operate unattended on a utility grid, would demonstrate reliable operation and would help establish the quality assurance and maintainability requirements for future wind turbine projects. A modified failure modes and effects analysis during the design phase, minimal hardware inspections during parts fabrication, and three simple documents to control activities during machine construction and operation were presented.

  7. Reliability and quality assurance on the MOD 2 wind system

    NASA Technical Reports Server (NTRS)

    Mason, W. E. B.; Jones, B. G.

    1981-01-01

    The Safety, Reliability, and Quality Assurance (R&QA) approach developed for the largest wind turbine generator, the Mod 2, is described. The R&QA approach assures that the machine is not hazardous to the public or to the operating personnel, is operated unattended on a utility grid, demonstrates reliable operation, and helps establish the quality assurance and maintainability requirements for future wind turbine projects. The significant guideline consisted of a failure modes and effects analysis (FMEA) during the design phase, hardware inspections during parts fabrication, and three simple documents to control activities during machine construction and operation.

  8. A New Tissue Resonator Indenter Device and Reliability Study

    PubMed Central

    Jia, Ming; Zu, Jean W.; Hariri, Alireza

    2011-01-01

    Knowledge of tissue mechanical properties is widely required by medical applications, such as disease diagnostics, surgery operation, simulation, planning, and training. A new portable device, called Tissue Resonator Indenter Device (TRID), has been developed for measurement of regional viscoelastic properties of soft tissues at the Bio-instrument and Biomechanics Lab of the University of Toronto. As a device for soft tissue properties in-vivo measurements, the reliability of TRID is crucial. This paper presents TRID’s working principle and the experimental study of TRID’s reliability with respect to inter-reliability, intra-reliability, and the indenter misalignment effect as well. PMID:22346623

  9. Reliable aerial thermography for energy conservation

    NASA Technical Reports Server (NTRS)

    Jack, J. R.; Bowman, R. L.

    1981-01-01

    A method for energy conservation, the aerial thermography survey, is discussed. It locates sources of energy losses and wasteful energy management practices. An operational map is presented for clear sky conditions. The map outlines the key environmental conditions conductive to obtaining reliable aerial thermography. The map is developed from defined visual and heat loss discrimination criteria which are quantized based on flat roof heat transfer calculations.

  10. Reliability/Maintainability/Testability Design for Dormancy

    DTIC Science & Technology

    1988-05-01

    productive. In general, the advantage of imple- menting confidence testing increases as an inverse function of non- operating reliability. Mathematical models ...applying the over-stress technique. These models are: the Arrhenius Model , the Eyring Model , the Inverse Power Model , and the 10-Degree Rule. The...stress n = c + (d/kT) The Inverse Power model has been applied to problems such as the fa- tigue testing of metals, the dielectric breakdown of

  11. Sonar Transducer Reliability Improvement Program FY80.

    DTIC Science & Technology

    1980-01-01

    band Threshold - less than ±2 dB variation from the specified value over operational frequency band The Sonar Transducer Reliability Improvement...were Qetiker preformed clamps, Band -It preformed clamps, and Band -It Scru-Loct retrofittable clamps. *TASK 5: Manufacture Instrumented Connectors Under...cycle 6 PRE-kORM 10 PU-U Cable bond failure, Remove from test after DSS-3 under gap in clamp cycle 5 OETIKER 11 N-G " ring leakage was Removed from

  12. Barriers to Achieving Mentally Agile Junior Leaders

    DTIC Science & Technology

    2009-01-21

    To help answer this question, this paper will describe the operational environment the agile leader must be prepared to operate within and the...senior leadership identified their need over eight years ago? To help answer this question, this paper will describe the operational environment the agile...to the reader. BARRIERS TO ACHIEVING MENTALLY AGILE JUNIOR LEADERS Persistent conflict and change characterize the strategic environment . We have

  13. Achieving quality assurance through clinical audit.

    PubMed

    Patel, Seraphim

    2010-06-01

    Audit is a crucial component of improvements to the quality of patient care. Clinical audits are undertaken to help ensure that patients can be given safe, reliable and dignified care, and to encourage them to self-direct their recovery. Such audits are undertaken also to help reduce lengths of patient stay in hospital, readmission rates and delays in discharge. This article describes the stages of clinical audit and the support required to achieve organisational core values.

  14. SLAC modulator system improvements and reliability results

    SciTech Connect

    Donaldson, A.R.

    1998-06-01

    In 1995, an improvement project was completed on the 244 klystron modulators in the linear accelerator. The modulator system has been previously described. This article offers project details and their resulting effect on modulator and component reliability. Prior to the project, the authors had collected four operating cycles (1991 through 1995) of MTTF data. In this discussion, the '91 data will be excluded since the modulators operated at 60 Hz. The five periods following the '91 run were reviewed due to the common repetition rate at 120 Hz.

  15. Reliability and lifetime predictions of SLC klystrons

    SciTech Connect

    Allen, M.A.; Callin, R.S.; Fowkes, W.R.; Lee, T.G.; Vlieks, A.E.

    1989-03-01

    The energy upgrade of SLAC, with the first of the new 67 MW SLAC Linear Collider (SLC) klystrons, began over four years ago. Today there are over 200 of these klystrons in operation. As a result, there is a wealth klystron performance and failure information that enables reasonable predictions to be made on life expectancy and reliability. Data from initial tests, follow-up tests and daily operation monitoring on the accelerator is stores for analysis. Presented here are life expectancy predictions with particular emphasis on cathode life. Also, based on this data, we will discuss some of the principal modes of failure. 3 refs., 2 figs.

  16. Sonar Transducer Reliability Improvement Program FY 80

    DTIC Science & Technology

    1980-10-01

    Polyphenylene Sulfide 15,320 23,000 Nylon 6/10 14,070 26,000 High-Strength Nylon (ZYTEL) 11,270 24,000 Amorphous Nylon 14,139 25,000 PBT Polyester...transducer receiving sensitivity Goal -- less than ±1 dB variation from the specified value over operational frequency band . Threshold - less than ±2 dB...variation from the specified value over operational feequency band . rhe Sonar Transducer Reliability Impruvemen: Program (STRIP) is a part of Program

  17. Preliminary evaluation and experimentation of the push-slip method for achieving micrometer and submicrometer step sizes with a miniature piezoactuated three-legged robot operating under high normal

    NASA Astrophysics Data System (ADS)

    Martel, Sylvain M.; Saraswat, Anant; Michel, Arthur; Hunter, Ian W.

    2000-10-01

    The NanoWalker is a miniature autonomous wireless robot under development. The robot is designed to accomplish complex tasks at the molecular and atomic scales. One concern is the total mass of the robot. With all the components including the mechanical structure and the complex electronic system necessary to embed the required functionality of throughput for such tasks, the mass of such a robot is estimated to be in the range of 100-200 grams depending on tradeoffs in the final design. With such a mass and limitations on the maximum voltage and current outputs that can be generated in a small form factor to deflect the piezo-ceramic legs with high-precision, a preliminary evaluation and experimentation phase of the motion behavior is essential prior to completing the final desing. It is shown both theoretically and experimentally that adequate motions are possible under such high normal forces. This was achieved through a new walking strategy referred to here as the push-slip method. The method uses the high normal forces combined with the resulting coefficient of friction between the termination of each leg and the walking surface to create initial opposite forces to the bending forces of each leg. These opposite forces, bounded by the maximum static force of friction, can be used for pushing or slipping through additional torque if the bending forces are applied reciprocal or in the direction of intended motions respectively. With the right parameters combined with tight and proper synchronizations of the legs, very effective motions can be achieved.

  18. Systems Issues In Terrestrial Fiber Optic Link Reliability

    NASA Astrophysics Data System (ADS)

    Spencer, James L.; Lewin, Barry R.; Lee, T. Frank S.

    1990-01-01

    This paper reviews fiber optic system reliability issues from three different viewpoints - availability, operating environment, and evolving technologies. Present availability objectives for interoffice links and for the distribution loop must be re-examined for applications such as the Synchronous Optical Network (SONET), Fiber-to-the-Home (FTTH), and analog services. The hostile operating environments of emerging applications (such as FTTH) must be carefully considered in system design as well as reliability assessments. Finally, evolving technologies might require the development of new reliability testing strategies.

  19. Wind turbine reliability : a database and analysis approach.

    SciTech Connect

    Linsday, James; Briand, Daniel; Hill, Roger Ray; Stinebaugh, Jennifer A.; Benjamin, Allan S.

    2008-02-01

    The US wind Industry has experienced remarkable growth since the turn of the century. At the same time, the physical size and electrical generation capabilities of wind turbines has also experienced remarkable growth. As the market continues to expand, and as wind generation continues to gain a significant share of the generation portfolio, the reliability of wind turbine technology becomes increasingly important. This report addresses how operations and maintenance costs are related to unreliability - that is the failures experienced by systems and components. Reliability tools are demonstrated, data needed to understand and catalog failure events is described, and practical wind turbine reliability models are illustrated, including preliminary results. This report also presents a continuing process of how to proceed with controlling industry requirements, needs, and expectations related to Reliability, Availability, Maintainability, and Safety. A simply stated goal of this process is to better understand and to improve the operable reliability of wind turbine installations.

  20. Developing Ultra Reliable Life Support for the Moon and Mars

    NASA Technical Reports Server (NTRS)

    Jones, Harry W.

    2009-01-01

    Recycling life support systems can achieve ultra reliability by using spares to replace failed components. The added mass for spares is approximately equal to the original system mass, provided the original system reliability is not very low. Acceptable reliability can be achieved for the space shuttle and space station by preventive maintenance and by replacing failed units, However, this maintenance and repair depends on a logistics supply chain that provides the needed spares. The Mars mission must take all the needed spares at launch. The Mars mission also must achieve ultra reliability, a very low failure rate per hour, since it requires years rather than weeks and cannot be cut short if a failure occurs. Also, the Mars mission has a much higher mass launch cost per kilogram than shuttle or station. Achieving ultra reliable space life support with acceptable mass will require a well-planned and extensive development effort. Analysis must define the reliability requirement and allocate it to subsystems and components. Technologies, components, and materials must be designed and selected for high reliability. Extensive testing is needed to ascertain very low failure rates. Systems design should segregate the failure causes in the smallest, most easily replaceable parts. The systems must be designed, produced, integrated, and tested without impairing system reliability. Maintenance and failed unit replacement should not introduce any additional probability of failure. The overall system must be tested sufficiently to identify any design errors. A program to develop ultra reliable space life support systems with acceptable mass must start soon if it is to produce timely results for the moon and Mars.

  1. Improving Search Engine Reliability

    NASA Astrophysics Data System (ADS)

    Pruthi, Jyoti; Kumar, Ela

    2010-11-01

    Search engines on the Internet are used daily to access and find information. While these services are providing an easy way to find information globally, they are also suffering from artificially created false results. This paper describes two techniques that are being used to manipulate the search engines: spam pages (used to achieve higher rankings on the result page) and cloaking (used to feed falsified data into search engines). This paper also describes two proposed methods to fight this kind of misuse, algorithms for both of the formerly mentioned cases of spamdexing.

  2. Secure Reliable Processing Systems

    DTIC Science & Technology

    1984-02-21

    specification successfully executed by application processes, technique draws from both the techniques of abstract data 121 Communications February 1980 of...J. and Farber. David A. "A \\lod’l for Verification of Data Security in Operating Systems." Communications of the ACM. Vol.21. No.9. September 1978. pp...the data being communicated exists in dleanext form as it is passed from one encrypted link to the next by the switch. Therefore the software in the

  3. Improving reliability of live/dead cell counting through automated image mosaicing.

    PubMed

    Piccinini, Filippo; Tesei, Anna; Paganelli, Giulia; Zoli, Wainer; Bevilacqua, Alessandro

    2014-12-01

    Cell counting is one of the basic needs of most biological experiments. Numerous methods and systems have been studied to improve the reliability of counting. However, at present, manual cell counting performed with a hemocytometer still represents the gold standard, despite several problems limiting reproducibility and repeatability of the counts and, at the end, jeopardizing their reliability in general. We present our own approach based on image processing techniques to improve counting reliability. It works in two stages: first building a high-resolution image of the hemocytometer's grid, then counting the live and dead cells by tagging the image with flags of different colours. In particular, we introduce GridMos (http://sourceforge.net/p/gridmos), a fully-automated mosaicing method to obtain a mosaic representing the whole hemocytometer's grid. In addition to offering more significant statistics, the mosaic "freezes" the culture status, thus permitting analysis by more than one operator. Finally, the mosaic achieved can thus be tagged by using an image editor, thus markedly improving counting reliability. The experiments performed confirm the improvements brought about by the proposed counting approach in terms of both reproducibility and repeatability, also suggesting the use of a mosaic of an entire hemocytometer's grid, then labelled trough an image editor, as the best likely candidate for the new gold standard method in cell counting.

  4. Overview of ten-year operation of the superconducting linear accelerator at the Spallation Neutron Source

    NASA Astrophysics Data System (ADS)

    Kim, S.-H.; Afanador, R.; Barnhart, D. L.; Crofford, M.; Degraff, B. D.; Doleans, M.; Galambos, J.; Gold, S. W.; Howell, M. P.; Mammosser, J.; McMahan, C. J.; Neustadt, T. S.; Peters, C.; Saunders, J. W.; Strong, W. H.; Vandygriff, D. J.; Vandygriff, D. M.

    2017-04-01

    The Spallation Neutron Source (SNS) has acquired extensive operational experience of a pulsed proton superconducting linear accelerator (SCL) as a user facility. Numerous lessons have been learned in its first 10 years operation to achieve a stable and reliable operation of the SCL. In this paper, an overview of the SNS SCL design, qualification of superconducting radio frequency (SRF) cavities and ancillary subsystems, an overview of the SNS cryogenic system, the SCL operation including SCL output energy history and downtime statistics, performance stability of the SRF cavities, efforts for SRF cavity performance recovery and improvement at the SNS, and maintenance activities for cryomodules are introduced.

  5. Overview of ten-year operation of the superconducting linear accelerator at the Spallation Neutron Source

    DOE PAGES

    Kim, Sang-Ho; Afanador, Ralph; Barnhart, Debra L.; ...

    2017-02-04

    The Spallation Neutron Source (SNS) has acquired extensive operational experience of a pulsed proton superconducting linear accelerator (SCL) as a user facility. Numerous lessons have been learned in its first 10 years operation to achieve a stable and reliable operation of the SCL. In this paper, an overview of the SNS SCL design, qualification of superconducting radio frequency (SRF) cavities and ancillary subsystems, an overview of the SNS cryogenic system, the SCL operation including SCL output energy history and downtime statistics, performance stability of the SRF cavities, efforts for SRF cavity performance recovery and improvement at the SNS, and maintenancemore » activities for cryomodules are introduced.« less

  6. Development of brain systems for nonsymbolic numerosity and the relationship to formal math academic achievement

    PubMed Central

    Haist, Frank; Wazny, Jarnet H.; Toomarian, Elizabeth; Adamo, Maha

    2015-01-01

    A central question in cognitive and educational neuroscience is whether brain operations supporting non-linguistic intuitive number sense (numerosity) predict individual acquisition and academic achievement for symbolic or “formal” math knowledge. Here, we conducted a developmental functional MRI study of nonsymbolic numerosity task performance in 44 participants including 14 school age children (6–12 years-old), 14 adolescents (13–17 years-old), and 16 adults and compared a brain activity measure of numerosity precision to scores from the Woodcock-Johnson III Broad Math index of math academic achievement. Accuracy and reaction time from the numerosity task did not reliably predict formal math achievement. We found a significant positive developmental trend for improved numerosity precision in the parietal cortex and intraparietal sulcus (IPS) specifically. Controlling for age and overall cognitive ability, we found a reliable positive relationship between individual math achievement scores and parietal lobe activity only in children. In addition, children showed robust positive relationships between math achievement and numerosity precision within ventral stream processing areas bilaterally. The pattern of results suggests a dynamic developmental trajectory for visual discrimination strategies that predict the acquisition of formal math knowledge. In adults, the efficiency of visual discrimination marked by numerosity acuity in ventral occipital-temporal cortex and hippocampus differentiated individuals with better or worse formal math achievement, respectively. Overall, these results suggest that two different brain systems for nonsymbolic numerosity acuity may contribute to individual differences in math achievement and that the contribution of these systems differs across development. PMID:25327879

  7. Reliability assessment of autonomous power systems incorporating HVDC interconnection links

    SciTech Connect

    Dialynas, E.N.; Koskolos, N.C.; Agoris, D.

    1996-01-01

    The objective of this paper is to present an improved computational method for the overall reliability assessment of autonomous power systems that may or may not contain HVdc interconnection links. This is a hybrid method based on a Monte-Carlo simulation sequential approach which incorporates an analytical approach for the reliability modeling of the HVdc transmission links. The developed models and techniques have been implemented into a computer program that can be used to simulate the operational practices and characteristics of the overall system under study efficiently and realistically. A set of reliability indices are calculated for each load-point of interest and the entire system while a set of additional indices is calculated for quantifying the reliability performance of the interconnection links under the specified operating requirements. The analysis of a practical system is also included for a number of studies representing its various operating and design characteristics.

  8. Aligning Items and Achievement Levels: A Study Comparing Expert Judgments

    ERIC Educational Resources Information Center

    Kaliski, Pamela; Huff, Kristen; Barry, Carol

    2011-01-01

    For educational achievement tests that employ multiple-choice (MC) items and aim to reliably classify students into performance categories, it is critical to design MC items that are capable of discriminating student performance according to the stated achievement levels. This is accomplished, in part, by clearly understanding how item design…

  9. CEBAF Accelerator Achievements

    NASA Astrophysics Data System (ADS)

    Chao, Y. C.; Drury, M.; Hovater, C.; Hutton, A.; Krafft, G. A.; Poelker, M.; Reece, C.; Tiefenback, M.

    2011-05-01

    In the past decade, nuclear physics users of Jefferson Lab's Continuous Electron Beam Accelerator Facility (CEBAF) have benefited from accelerator physics advances and machine improvements. As of early 2011, CEBAF operates routinely at 6 GeV, with a 12 GeV upgrade underway. This article reports highlights of CEBAF's scientific and technological evolution in the areas of cryomodule refurbishment, RF control, polarized source development, beam transport for parity experiments, magnets and hysteresis handling, beam breakup, and helium refrigerator operational optimization.

  10. Design and operating guidelines for nuclear power plant condensers

    SciTech Connect

    Not Available

    1991-09-01

    Recommendations and associated technical justifications are provided for the design and operation of condensate polishing systems. Both deep bed and powdered resin system are addressed. The objective of the guidelines is to ensure that impurity levels in the PWR secondary cycle are reduced to the minimum achievable levels through proper design and operation of the condensate polisher system. Reduction of the condensate polisher to the steam generators has been demonstrated to improve steam generator reliability and limit corrosion of steam generator materials. 19 refs., 12 figs., 4 tabs.

  11. Design-for-reliability (DfR) of aerospace electronics: Attributes and challenges

    NASA Astrophysics Data System (ADS)

    Bensoussan, A.; Suhir, E.

    The next generation of multi-beam satellite systems that would be able to provide effective interactive communication services will have to operate within a highly flexible architecture. One option to develop such flexibility is to employ microwaves and/or optoelectronic components and to make them reliable. The use of optoelectronic devices, equipments and systems will result indeed in significant improvement in the state-of-the-art only provided that the new designs will suggest a novel and effective architecture that will combine the merits of good functional performance, satisfactory mechanical (structural) reliability and high cost effectiveness. The obvious challenge is the ability to design and fabricate equipment based on EEE components that would be able to successfully withstand harsh space environments for the entire duration of the mission. It is imperative that the major players in the space industry, such as manufacturers, industrial users, and space agencies, understand the importance and the limits of the achievable quality and reliability of optoelectronic devices operated in harsh environments. It is equally imperative that the physics of possible failures is well understood and, if necessary, minimized, and that adequate Quality Standards are developed and employed. The space community has to identify and to develop the strategic approach for validating optoelectronic products. This should be done with consideration of numerous intrinsic and extrinsic requirements for the systems' performance. When considering a particular next generation optoelectronic space system, the space community needs to address the following major issues: proof of concept for this system, proof of reliability and proof of performance. This should be done with taking into account the specifics of the anticipated application. High operational reliability cannot be left to the prognostics and health monitoring/management (PHM) effort and stage, no matter how important and

  12. Reliability centered maintenance in astronomical infrastructure facilities

    NASA Astrophysics Data System (ADS)

    Ansorge, W. R.

    2006-06-01

    Hundreds of mirror segment, thousands of high precision actuators, highly complex mechanical, hydraulic, electrical and other technology subsystems, and highly sophisticated control systems: an ELT system consists of millions of individual parts and components, each of them may fail and lead to a partial or complete system breakdown. The traditional maintenance concepts characterized by predefined preventive maintenance activities and rigid schedules are not suitable for handling this large number of potential failures and malfunctions and the extreme maintenance workload. New maintenance strategies have to be found suitable to increase reliability while reducing the cost of needless maintenance services. The Reliability Centred Maintenance (RCM) methodology is already used extensively by airlines, and in industrial and marine facilities and even by scientific institutions like NASA. Its application increases the operational reliability while reducing the cost of unnecessary maintenance activities and is certainly also a solution for current and future ELT facilities. RCM is a concept of developing a maintenance scheme based on the reliability of the various components of a system by using "feedback loops between instrument / system performance monitoring and preventive/corrective maintenance cycles." Ideally RCM has to be designed within a system and should be located in the requirement definition, the preliminary and final design phases of new equipment and complicated systems. However, under certain conditions, an implementation of RCM into the maintenance management strategy of already existing astronomical infrastructure facilities is also possible. This presentation outlines the principles of the RCM methodology, explains the advantages, and highlights necessary changes in the observatory development, operation and maintenance philosophies. Presently, it is the right time to implement RCM into current and future ELT projects and to save up to 50% maintenance

  13. Secure Reliable Processing Systems

    DTIC Science & Technology

    1981-07-01

    UCLA-ENG-7854), August 1978. Popek, G.J. and D.A. Farber. "A Model for Verification of Data Security in Operating Systems," Communications of the ACM...via covert channels is a data security problem. On the other hand, the unauthorized use of the system to communicate is a confinement problem. The...point here is that if there exists a communication channel, it may be accidentally used by a user and information leaked. For a system to be data secure

  14. Reliability of Wireless Sensor Networks

    PubMed Central

    Dâmaso, Antônio; Rosa, Nelson; Maciel, Paulo

    2014-01-01

    Wireless Sensor Networks (WSNs) consist of hundreds or thousands of sensor nodes with limited processing, storage, and battery capabilities. There are several strategies to reduce the power consumption of WSN nodes (by increasing the network lifetime) and increase the reliability of the network (by improving the WSN Quality of Service). However, there is an inherent conflict between power consumption and reliability: an increase in reliability usually leads to an increase in power consumption. For example, routing algorithms can send the same packet though different paths (multipath strategy), which it is important for reliability, but they significantly increase the WSN power consumption. In this context, this paper proposes a model for evaluating the reliability of WSNs considering the battery level as a key factor. Moreover, this model is based on routing algorithms used by WSNs. In order to evaluate the proposed models, three scenarios were considered to show the impact of the power consumption on the reliability of WSNs. PMID:25157553

  15. Nuclear weapon reliability evaluation methodology

    SciTech Connect

    Wright, D.L.

    1993-06-01

    This document provides an overview of those activities that are normally performed by Sandia National Laboratories to provide nuclear weapon reliability evaluations for the Department of Energy. These reliability evaluations are first provided as a prediction of the attainable stockpile reliability of a proposed weapon design. Stockpile reliability assessments are provided for each weapon type as the weapon is fielded and are continuously updated throughout the weapon stockpile life. The reliability predictions and assessments depend heavily on data from both laboratory simulation and actual flight tests. An important part of the methodology are the opportunities for review that occur throughout the entire process that assure a consistent approach and appropriate use of the data for reliability evaluation purposes.

  16. Reliable measurement of the receding contact angle.

    PubMed

    Korhonen, Juuso T; Huhtamäki, Tommi; Ikkala, Olli; Ras, Robin H A

    2013-03-26

    Surface wettability is usually evaluated by the contact angle between the perimeter of a water drop and the surface. However, this single measurement is not enough for proper characterization, and the so-called advancing and receding contact angles also need to be measured. Measuring the receding contact angle can be challenging, especially for extremely hydrophobic surfaces. We demonstrate a reliable procedure by using the common needle-in-the-sessile-drop method. Generally, the contact line movement needs to be followed, and true receding movement has to be distinguished from "pseudo-movement" occurring before the receding angle is reached. Depending on the contact angle hysteresis, the initial size of the drop may need to be surprisingly large to achieve a reliable result. Although our motivation for this work was the characterization of superhydrophobic surfaces, we also show that this method works universally ranging from hydrophilic to superhydrophobic surfaces.

  17. Probabilistic Methods for Structural Design and Reliability

    NASA Technical Reports Server (NTRS)

    Chamis, Christos C.; Whitlow, Woodrow, Jr. (Technical Monitor)

    2002-01-01

    This report describes a formal method to quantify structural damage tolerance and reliability in the presence of a multitude of uncertainties in turbine engine components. The method is based at the material behavior level where primitive variables with their respective scatter ranges are used to describe behavior. Computational simulation is then used to propagate the uncertainties to the structural scale where damage tolerance and reliability are usually specified. Several sample cases are described to illustrate the effectiveness, versatility, and maturity of the method. Typical results from this method demonstrate, that it is mature and that it can be used to probabilistically evaluate turbine engine structural components. It may be inferred from the results that the method is suitable for probabilistically predicting the remaining life in aging or in deteriorating structures, for making strategic projections and plans, and for achieving better, cheaper, faster products that give competitive advantages in world markets.

  18. Optimal Implementations for Reliable Circadian Clocks

    NASA Astrophysics Data System (ADS)

    Hasegawa, Yoshihiko; Arita, Masanori

    2014-09-01

    Circadian rhythms are acquired through evolution to increase the chances for survival through synchronizing with the daylight cycle. Reliable synchronization is realized through two trade-off properties: regularity to keep time precisely, and entrainability to synchronize the internal time with daylight. We find by using a phase model with multiple inputs that achieving the maximal limit of regularity and entrainability entails many inherent features of the circadian mechanism. At the molecular level, we demonstrate the role sharing of two light inputs, phase advance and delay, as is well observed in mammals. At the behavioral level, the optimal phase-response curve inevitably contains a dead zone, a time during which light pulses neither advance nor delay the clock. We reproduce the results of phase-controlling experiments entrained by two types of periodic light pulses. Our results indicate that circadian clocks are designed optimally for reliable clockwork through evolution.

  19. Achieving Energy Efficiency Through Real-Time Feedback

    SciTech Connect

    Nesse, Ronald J.

    2011-09-01

    Through the careful implementation of simple behavior change measures, opportunities exist to achieve strategic gains, including greater operational efficiencies, energy cost savings, greater tenant health and ensuing productivity and an improved brand value through sustainability messaging and achievement.

  20. SALT and Spelling Achievement.

    ERIC Educational Resources Information Center

    Nelson, Joan

    A study investigated the effects of suggestopedic accelerative learning and teaching (SALT) on the spelling achievement, attitudes toward school, and memory skills of fourth-grade students. Subjects were 20 male and 28 female students from two self-contained classrooms at Kennedy Elementary School in Rexburg, Idaho. The control classroom and the…

  1. Iowa Women of Achievement.

    ERIC Educational Resources Information Center

    Ohrn, Deborah Gore, Ed.

    1993-01-01

    This issue of the Goldfinch highlights some of Iowa's 20th century women of achievement. These women have devoted their lives to working for human rights, education, equality, and individual rights. They come from the worlds of politics, art, music, education, sports, business, entertainment, and social work. They represent Native Americans,…

  2. Schools Achieving Gender Equity.

    ERIC Educational Resources Information Center

    Revis, Emma

    This guide is designed to assist teachers presenting the Schools Achieving Gender Equity (SAGE) curriculum for vocational education students, which was developed to align gender equity concepts with the Kentucky Education Reform Act (KERA). Included in the guide are lesson plans for classes on the following topics: legal issues of gender equity,…

  3. Achieving Peace through Education.

    ERIC Educational Resources Information Center

    Clarken, Rodney H.

    While it is generally agreed that peace is desirable, there are barriers to achieving a peaceful world. These barriers are classified into three major areas: (1) an erroneous view of human nature; (2) injustice; and (3) fear of world unity. In a discussion of these barriers, it is noted that although the consciousness and conscience of the world…

  4. Explorations in achievement motivation

    NASA Technical Reports Server (NTRS)

    Helmreich, Robert L.

    1982-01-01

    Recent research on the nature of achievement motivation is reviewed. A three-factor model of intrinsic motives is presented and related to various criteria of performance, job satisfaction and leisure activities. The relationships between intrinsic and extrinsic motives are discussed. Needed areas for future research are described.

  5. Increasing Male Academic Achievement

    ERIC Educational Resources Information Center

    Jackson, Barbara Talbert

    2008-01-01

    The No Child Left Behind legislation has brought greater attention to the academic performance of American youth. Its emphasis on student achievement requires a closer analysis of assessment data by school districts. To address the findings, educators must seek strategies to remedy failing results. In a mid-Atlantic district of the Unites States,…

  6. Appraising Reading Achievement.

    ERIC Educational Resources Information Center

    Ediger, Marlow

    To determine quality sequence in pupil progress, evaluation approaches need to be used which guide the teacher to assist learners to attain optimally. Teachers must use a variety of procedures to appraise student achievement in reading, because no one approach is adequate. Appraisal approaches might include: (1) observation and subsequent…

  7. Cognitive Processes and Achievement.

    ERIC Educational Resources Information Center

    Hunt, Dennis; Randhawa, Bikkar S.

    For a group of 165 fourth- and fifth-grade students, four achievement test scores were correlated with success on nine tests designed to measure three cognitive functions: sustained attention, successive processing, and simultaneous processing. This experiment was designed in accordance with Luria's model of the three functional units of the…

  8. Graders' Mathematics Achievement

    ERIC Educational Resources Information Center

    Bond, John B.; Ellis, Arthur K.

    2013-01-01

    The purpose of this experimental study was to investigate the effects of metacognitive reflective assessment instruction on student achievement in mathematics. The study compared the performance of 141 students who practiced reflective assessment strategies with students who did not. A posttest-only control group design was employed, and results…

  9. Achieving All Our Ambitions

    ERIC Educational Resources Information Center

    Hartley, Tricia

    2009-01-01

    National learning and skills policy aims both to build economic prosperity and to achieve social justice. Participation in higher education (HE) has the potential to contribute substantially to both aims. That is why the Campaign for Learning has supported the ambition to increase the proportion of the working-age population with a Level 4…

  10. Improving Educational Achievement.

    ERIC Educational Resources Information Center

    New York University Education Quarterly, 1979

    1979-01-01

    This is a slightly abridged version of the report of the National Academy of Education panel, convened at the request of HEW Secretary Joseph Califano and Assistant Secretary for Education Mary F. Berry, to study recent declines in student achievement and methods of educational improvement. (SJL)

  11. The Achievement Club

    ERIC Educational Resources Information Center

    Rogers, Ibram

    2009-01-01

    When Gabrielle Carpenter became a guidance counselor in Northern Virginia nine years ago, she focused on the academic achievement gap and furiously tried to close it. At first, she was compelled by tremendous professional interest. However, after seeing her son lose his zeal for school, Carpenter joined forces with other parents to form an…

  12. Achievement in Problem Solving

    ERIC Educational Resources Information Center

    Friebele, David

    2010-01-01

    This Action Research Project is meant to investigate the effects of incorporating research-based instructional strategies into instruction and their subsequent effect on student achievement in the area of problem-solving. The two specific strategies utilized are the integration of manipulatives and increased social interaction on a regular basis.…

  13. Essays on Educational Achievement

    ERIC Educational Resources Information Center

    Ampaabeng, Samuel Kofi

    2013-01-01

    This dissertation examines the determinants of student outcomes--achievement, attainment, occupational choices and earnings--in three different contexts. The first two chapters focus on Ghana while the final chapter focuses on the US state of Massachusetts. In the first chapter, I exploit the incidence of famine and malnutrition that resulted to…

  14. Advancing Student Achievement

    ERIC Educational Resources Information Center

    Walberg, Herbert J.

    2010-01-01

    For the last half century, higher spending and many modern reforms have failed to raise the achievement of students in the United States to the levels of other economically advanced countries. A possible explanation, says Herbert Walberg, is that much current education theory is ill informed about scientific psychology, often drawing on fads and…

  15. NCLB: Achievement Robin Hood?

    ERIC Educational Resources Information Center

    Bracey, Gerald W.

    2008-01-01

    In his "Wall Street Journal" op-ed on the 25th of anniversary of "A Nation At Risk", former assistant secretary of education Chester E. Finn Jr. applauded the report for turning U.S. education away from equality and toward achievement. It was not surprising, then, that in mid-2008, Finn arranged a conference to examine the…

  16. Mass and Reliability System (MaRS)

    NASA Technical Reports Server (NTRS)

    Barnes, Sarah

    2016-01-01

    The Safety and Mission Assurance (S&MA) Directorate is responsible for mitigating risk, providing system safety, and lowering risk for space programs from ground to space. The S&MA is divided into 4 divisions: The Space Exploration Division (NC), the International Space Station Division (NE), the Safety & Test Operations Division (NS), and the Quality and Flight Equipment Division (NT). The interns, myself and Arun Aruljothi, will be working with the Risk & Reliability Analysis Branch under the NC Division's. The mission of this division is to identify, characterize, diminish, and communicate risk by implementing an efficient and effective assurance model. The team utilizes Reliability and Maintainability (R&M) and Probabilistic Risk Assessment (PRA) to ensure decisions concerning risks are informed, vehicles are safe and reliable, and program/project requirements are realistic and realized. This project pertains to the Orion mission, so it is geared toward a long duration Human Space Flight Program(s). For space missions, payload is a critical concept; balancing what hardware can be replaced by components verse by Orbital Replacement Units (ORU) or subassemblies is key. For this effort a database was created that combines mass and reliability data, called Mass and Reliability System or MaRS. The U.S. International Space Station (ISS) components are used as reference parts in the MaRS database. Using ISS components as a platform is beneficial because of the historical context and the environment similarities to a space flight mission. MaRS uses a combination of systems: International Space Station PART for failure data, Vehicle Master Database (VMDB) for ORU & components, Maintenance & Analysis Data Set (MADS) for operation hours and other pertinent data, & Hardware History Retrieval System (HHRS) for unit weights. MaRS is populated using a Visual Basic Application. Once populated, the excel spreadsheet is comprised of information on ISS components including

  17. A fourth generation reliability predictor

    NASA Technical Reports Server (NTRS)

    Bavuso, Salvatore J.; Martensen, Anna L.

    1988-01-01

    A reliability/availability predictor computer program has been developed and is currently being beta-tested by over 30 US companies. The computer program is called the Hybrid Automated Reliability Predictor (HARP). HARP was developed to fill an important gap in reliability assessment capabilities. This gap was manifested through the use of its third-generation cousin, the Computer-Aided Reliability Estimation (CARE III) program, over a six-year development period and an additional three-year period during which CARE III has been in the public domain. The accumulated experience of the over 30 establishments now using CARE III was used in the development of the HARP program.

  18. Tutorial: Performance and reliability in redundant disk arrays

    NASA Technical Reports Server (NTRS)

    Gibson, Garth A.

    1993-01-01

    A disk array is a collection of physically small magnetic disks that is packaged as a single unit but operates in parallel. Disk arrays capitalize on the availability of small-diameter disks from a price-competitive market to provide the cost, volume, and capacity of current disk systems but many times their performance. Unfortunately, relative to current disk systems, the larger number of components in disk arrays leads to higher rates of failure. To tolerate failures, redundant disk arrays devote a fraction of their capacity to an encoding of their information. This redundant information enables the contents of a failed disk to be recovered from the contents of non-failed disks. The simplest and least expensive encoding for this redundancy, known as N+1 parity is highlighted. In addition to compensating for the higher failure rates of disk arrays, redundancy allows highly reliable secondary storage systems to be built much more cost-effectively than is now achieved in conventional duplicated disks. Disk arrays that combine redundancy with the parallelism of many small-diameter disks are often called Redundant Arrays of Inexpensive Disks (RAID). This combination promises improvements to both the performance and the reliability of secondary storage. For example, IBM's premier disk product, the IBM 3390, is compared to a redundant disk array constructed of 84 IBM 0661 3 1/2-inch disks. The redundant disk array has comparable or superior values for each of the metrics given and appears likely to cost less. In the first section of this tutorial, I explain how disk arrays exploit the emergence of high performance, small magnetic disks to provide cost-effective disk parallelism that combats the access and transfer gap problems. The flexibility of disk-array configurations benefits manufacturer and consumer alike. In contrast, I describe in this tutorial's second half how parallelism, achieved through increasing numbers of components, causes overall failure rates to rise

  19. A comparative evaluation of the reliability improvement in line replaceable units warranted under the F-16 reliability improvement warranty

    NASA Astrophysics Data System (ADS)

    Lemke, S. J.

    1985-09-01

    This thesis examined the effects a reliability improvement warranty (RIW) had on the actual operational reliability of the warranted avionics equipment. To accomplish this, the most comprehensive DOD application of RIW to date, the F-16 RIW, was investigated. This study was designed to answer the question of whether or not a warranted weapons system was significantly more reliable than it would have been without the warranty. Specifically, the observed mean flight hours between failures (MFHBFs) and the observed reliability growths of the warranted F-16 equipment were compared to those of functionally similar non-warranted F-15 equipment. Also, the reliability growth of the F-16 warranted equipment was compared to that of other non-warranted F-16 equipment. The AMSAA Reliability Growth Model was used as a basis for the reliability growth analyses. Comparable life cycle time periods for each aircraft were studied, using AFM 66-1 D056 failure and flight time data. The results of the investigation indicated that, in general, the observed MFHBFs of the F-16 warranted equipment were statistically greater than the MFHBFs of the equivalent F-15 equipment. The same could not be concluded for the reliability growths of the F-16 and equivalent F-15 equipment. However, the reliability growth of the warranted F-16 equipment was found to be statistically greater than the reliability growth of the non-warranted F-16 equipment.

  20. Space reliability technology - A historical perspective

    NASA Technical Reports Server (NTRS)

    Cohen, H.

    1984-01-01

    The progressive improvements in reliability of launch vehicles is traced from the Vanguard rocket to the STS. The Vanguard, built with minimal redundancy and a high mass ratio, was used as an operational vehicle midway through its test program in an attempt to meet the perceived challenge represented by the Sputnik. The fourth Vanguard failed due to inadequate contamination prevention and lack of inspection ports. Automatic firing sequences were adopted for the Titan rockets, which were an order of magnitude larger than the Vanguard and therefore had room for interior inspections. Qualification testing and reporting were introduced for components, along with X ray inspection of fuel tank welds. Dual systems were added for flight critical components when the Titan became man-rated for the Gemini program. Designs incorporated full failure mode effects and criticality analyses for the Apollo program, which exposed the limits of applicability of numerical reliability models. Fault tree analyses and program milestone reviews were initiated. The worth of man-in-the-loop in space activities for reliability was demonstrated with the rescue of Skylab after solar panel and meteoroid shield failures. It is now the reliability of the payload, rather than the vehicle, that is questioned for Shuttle launches.