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Sample records for accelerated reliability testing

  1. OPTIMUM DESIGN OF EXPERIMENTS FOR ACCELERATED RELIABILITY TESTING

    Directory of Open Access Journals (Sweden)

    Sebastian Marian ZAHARIA

    2014-05-01

    Full Text Available In this paper is presented a case study that demonstrates how design to experiments (DOE information can be used to design better accelerated reliability tests. In the case study described in this paper, will be done a comparison and optimization between main accelerated reliability test plans (3 Level Best Standard Plan, 3 Level Best Compromise Plan, 3 Level Best Equal Expected Number Failing Plan, 3 Level 4:2:1 Allocation Plan. Before starting an accelerated reliability test, it is advisable to have a plan that helps in accurately estimating reliability at operating conditions while minimizing test time and costs. A test plan should be used to decide on the appropriate stress levels that should be used (for each stress type and the amount of the test units that need to be allocated to the different stress levels (for each combination of the different stress types' levels. For the case study it used ALTA 7 software what provides a complete analysis for data from accelerated reliability tests

  2. Design of Accelerated Reliability Test for CNC Motorized Spindle Based on Vibration Signal

    Directory of Open Access Journals (Sweden)

    Chen Chao

    2016-01-01

    Full Text Available Motorized spindle is the key functional component of CNC machining centers which is a mechatronics system with long life and high reliability. The reliability test cycle of motorized spindle is too long and infeasible. This paper proposes a new accelerated test for reliability evaluation of motorized spindle. By field reliability test, authors collect and calculate the load data including rotational speed, cutting force and torque. Load spectrum distribution law is analyzed. And authors design a test platform to apply the load spectrum. A new method to define the fuzzy acceleration factor based on the vibration signal is proposed. Then the whole test plan of accelerated reliability test is done.

  3. CERN Technical training 2008 - Learning for the LHC: Special Workshop demonstrating reliability with accelerated testing

    CERN Multimedia

    2008-01-01

    Larry Edson’s workshop will show examples of quantitative reliability predictions based upon accelerated testing and demonstrates that reliability testing during the prototyping phase will help ascertain product shortcomings. When these weak points are addressed and the redesigned product is re-tested, the reliability of that product will become much higher. These methodologies successfully used in industry might be exceedingly useful also for component development in particle physics where reliability is of utmost importance. This training will provide participants with the skills necessary to demonstrate reliability requirements using accelerated testing methods. The workshop will focus on accelerated test design that employs increased stress levels. This approach has the advantage of reducing test time, sample size and test facility resources. The methodologies taught are applicable to all types of stresses, spanning the electro...

  4. CERN Technical training 2008 - Learning for the LHC: Special workshop demonstrating reliability with accelerated testing

    CERN Multimedia

    2008-01-01

    Larry Edson’s workshop will show examples of quantitative reliability predictions based upon accelerated testing and demonstrate that reliability testing during the prototyping phase will help ascertain product shortcomings. When these weak points are addressed and the redesigned product is re-tested, the reliability of that product will become much higher. These methodologies successfully used in industry might be exceedingly useful also for component development in particle physics where reliability is of the utmost importance. This training will provide participants with the skills necessary to demonstrate reliability requirements using accelerated testing methods. The workshop will focus on accelerated test design that employs increased stress levels. This approach has the advantage of reducing test time, sample size and test facility resources. The methodologies taught are applicable to all types of stresses, spanning the elec...

  5. CERN Technical training 2008 - Learning for the LHC: Special Workshop demonstrating reliability with accelerated testing

    CERN Multimedia

    2008-01-01

    Larry Edson’s workshop will show examples of quantitative reliability predictions based upon accelerated testing and demonstrate that reliability testing during the prototyping phase will help ascertain product shortcomings. When these weak points are addressed and the redesigned product is re-tested, the reliability of that product will become much higher. These methodologies successfully used in industry might be exceedingly useful also for component development in particle physics where reliability is of the utmost importance. This training will provide participants with the skills necessary to demonstrate reliability requirements using accelerated testing methods. The workshop will focus on accelerated test design that employs increased stress levels. This approach has the advantage of reducing test time, sample size and test facility resources. The methodologies taught are applicable to all types of stresses, spanning the elec...

  6. The Accelerator Reliability Forum

    CERN Document Server

    Lüdeke, Andreas; Giachino, R

    2014-01-01

    A high reliability is a very important goal for most particle accelerators. The biennial Accelerator Reliability Workshop covers topics related to the design and operation of particle accelerators with a high reliability. In order to optimize the over-all reliability of an accelerator one needs to gather information on the reliability of many different subsystems. While a biennial workshop can serve as a platform for the exchange of such information, the authors aimed to provide a further channel to allow for a more timely communication: the Particle Accelerator Reliability Forum [1]. This contribution will describe the forum and advertise it’s usage in the community.

  7. A Reliability Accelerated Test of High-speed Punch Based on Failure Analysis

    Directory of Open Access Journals (Sweden)

    Chen Lan

    2016-01-01

    Full Text Available By analyzing the maintainability data of a certain high-speed punch, its main fault modes, such as oil/gas parts damage, parts damage and leakages, were identified. According to the fault signal measurability and the accelerated failure mechanism, the content and scheme of a reliability accelerated test (RAT were planned specifically, which was partly verified by some tests on a high-speed punch. This paper provides a basis for the RAT of high-speed punch.

  8. Enabling More than Moore: Accelerated Reliability Testing and Risk Analysis for Advanced Electronics Packaging

    Science.gov (United States)

    Ghaffarian, Reza; Evans, John W.

    2014-01-01

    For five decades, the semiconductor industry has distinguished itself by the rapid pace of improvement in miniaturization of electronics products-Moore's Law. Now, scaling hits a brick wall, a paradigm shift. The industry roadmaps recognized the scaling limitation and project that packaging technologies will meet further miniaturization needs or ak.a "More than Moore". This paper presents packaging technology trends and accelerated reliability testing methods currently being practiced. Then, it presents industry status on key advanced electronic packages, factors affecting accelerated solder joint reliability of area array packages, and IPC/JEDEC/Mil specifications for characterizations of assemblies under accelerated thermal and mechanical loading. Finally, it presents an examples demonstrating how Accelerated Testing and Analysis have been effectively employed in the development of complex spacecraft thereby reducing risk. Quantitative assessments necessarily involve the mathematics of probability and statistics. In addition, accelerated tests need to be designed which consider the desired risk posture and schedule for particular project. Such assessments relieve risks without imposing additional costs. and constraints that are not value added for a particular mission. Furthermore, in the course of development of complex systems, variances and defects will inevitably present themselves and require a decision concerning their disposition, necessitating quantitative assessments. In summary, this paper presents a comprehensive view point, from technology to systems, including the benefits and impact of accelerated testing in offsetting risk.

  9. A Study on the Storage Reliability of LSINS Based on Step-stress Accelerated Life Test

    Directory of Open Access Journals (Sweden)

    Teng Fei

    2015-01-01

    Full Text Available Based on the step-stress accelerated life test and the laser strap-down inertial navigation system, this paper studies the accelerated life model and the test method, provides the likelihood function, the likelihood equation and the two-order derivative when the stress level is k, evaluates the effectiveness of the method with the simulation test model established by MATLAB, applies the research findings in the storage reliability study of the XX laser strap-down inertial navigation system, and puts forward an effective evaluation method of the storage life of the inertial navigation system.

  10. Accelerator reliability workshop

    Energy Technology Data Exchange (ETDEWEB)

    Hardy, L.; Duru, Ph.; Koch, J.M.; Revol, J.L.; Van Vaerenbergh, P.; Volpe, A.M.; Clugnet, K.; Dely, A.; Goodhew, D

    2002-07-01

    About 80 experts attended this workshop, which brought together all accelerator communities: accelerator driven systems, X-ray sources, medical and industrial accelerators, spallation sources projects (American and European), nuclear physics, etc. With newly proposed accelerator applications such as nuclear waste transmutation, replacement of nuclear power plants and others. Reliability has now become a number one priority for accelerator designers. Every part of an accelerator facility from cryogenic systems to data storage via RF systems are concerned by reliability. This aspect is now taken into account in the design/budget phase, especially for projects whose goal is to reach no more than 10 interruptions per year. This document gathers the slides but not the proceedings of the workshop.

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

    Energy Technology Data Exchange (ETDEWEB)

    J. Francfort (INEEL); J. Argueta; M. Wehrey (Southern California Edison); D. Karner; L. Tyree (Electric Transportation Applications)

    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.

  12. Reliability and Lifetime Prediction of Remote Phosphor Plates in Solid-State Lighting Applications Using Accelerated Degradation Testing

    NARCIS (Netherlands)

    Yazdan Mehr, M.; Van Driel, W.D.; Zhang, G.Q.

    2015-01-01

    A methodology, based on accelerated degradation testing, is developed to predict the lifetime of remote phosphor plates used in solid-state lighting (SSL) applications. Both thermal stress and light intensity are used to accelerate degradation reaction in remote phosphor plates. A reliability model,

  13. Advanced Accelerated Power Cycling Test for Reliability Investigation of Power Device Modules

    DEFF Research Database (Denmark)

    Choi, Uimin; Jørgensen, Søren; Blaabjerg, Frede

    2016-01-01

    of tested power IGBT module. The various realistic electrical operating conditions close to real three-phase converter applications can be achieved by the simple control method. Further, by the proposed concept of applying the temperature stress, it is possible to apply various magnitudes of temperature......This paper presents an apparatus and methodology for an advanced accelerated power cycling test of insulated-gate bipolar transistor (IGBT) modules. In this test, the accelerated power cycling test can be performed under more realistic electrical operating conditions with online wear-out monitoring...... power cycling test setup is given. Then, an improved in situ junction temperature estimation method using on-state collector–emitter voltage VCE ON and load current is proposed. In addition, a procedure of advanced accelerated power cycling test and test results with 600 V, 30 A transfer molded IGBT...

  14. Accelerator Availability and Reliability Issues

    Energy Technology Data Exchange (ETDEWEB)

    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.

  15. Reliability and Validity of a New Test of Change-of-Direction Speed for Field-Based Sports: the Change-of-Direction and Acceleration Test (CODAT).

    Science.gov (United States)

    Lockie, Robert G; Schultz, Adrian B; Callaghan, Samuel J; Jeffriess, Matthew D; Berry, Simon P

    2013-01-01

    Field sport coaches must use reliable and valid tests to assess change-of-direction speed in their athletes. Few tests feature linear sprinting with acute change- of-direction maneuvers. The Change-of-Direction and Acceleration Test (CODAT) was designed to assess field sport change-of-direction speed, and includes a linear 5-meter (m) sprint, 45° and 90° cuts, 3- m sprints to the left and right, and a linear 10-m sprint. This study analyzed the reliability and validity of this test, through comparisons to 20-m sprint (0-5, 0-10, 0-20 m intervals) and Illinois agility run (IAR) performance. Eighteen Australian footballers (age = 23.83 ± 7.04 yrs; height = 1.79 ± 0.06 m; mass = 85.36 ± 13.21 kg) were recruited. Following familiarization, subjects completed the 20-m sprint, CODAT, and IAR in 2 sessions, 48 hours apart. Intra-class correlation coefficients (ICC) assessed relative reliability. Absolute reliability was analyzed through paired samples t-tests (p ≤ 0.05) determining between-session differences. Typical error (TE), coefficient of variation (CV), and differences between the TE and smallest worthwhile change (SWC), also assessed absolute reliability and test usefulness. For the validity analysis, Pearson's correlations (p ≤ 0.05) analyzed between-test relationships. Results showed no between-session differences for any test (p = 0.19-0.86). CODAT time averaged ~6 s, and the ICC and CV equaled 0.84 and 3.0%, respectively. The homogeneous sample of Australian footballers meant that the CODAT's TE (0.19 s) exceeded the usual 0.2 x standard deviation (SD) SWC (0.10 s). However, the CODAT is capable of detecting moderate performance changes (SWC calculated as 0.5 x SD = 0.25 s). There was a near perfect correlation between the CODAT and IAR (r = 0.92), and very large correlations with the 20-m sprint (r = 0.75-0.76), suggesting that the CODAT was a valid change-of-direction speed test. Due to movement specificity, the CODAT has value for field sport

  16. RELIABILITY AND VALIDITY OF A NEW TEST OF CHANGE-OF-DIRECTION SPEED FOR FIELD-BASED SPORTS: THE CHANGE-OF-DIRECTION AND ACCELERATION TEST (CODAT

    Directory of Open Access Journals (Sweden)

    Robert G. Lockie

    2013-03-01

    Full Text Available Field sport coaches must use reliable and valid tests to assess change-of-direction speed in their athletes. Few tests feature linear sprinting with acute change- of-direction maneuvers. The Change-of-Direction and Acceleration Test (CODAT was designed to assess field sport change-of-direction speed, and includes a linear 5-meter (m sprint, 45º and 90º cuts, 3- m sprints to the left and right, and a linear 10-m sprint. This study analyzed the reliability and validity of this test, through comparisons to 20-m sprint (0-5, 0-10, 0-20 m intervals and Illinois agility run (IAR performance. Eighteen Australian footballers (age = 23.83 ± 7.04 yrs; height = 1.79 ± 0.06 m; mass = 85.36 ± 13.21 kg were recruited. Following familiarization, subjects completed the 20-m sprint, CODAT, and IAR in 2 sessions, 48 hours apart. Intra-class correlation coefficients (ICC assessed relative reliability. Absolute reliability was analyzed through paired samples t-tests (p < 0.05 determining between-session differences. Typical error (TE, coefficient of variation (CV, and differences between the TE and smallest worthwhile change (SWC, also assessed absolute reliability and test usefulness. For the validity analysis, Pearson's correlations (p < 0.05 analyzed between-test relationships. Results showed no between-session differences for any test (p = 0.19-0.86. CODAT time averaged ~6 s, and the ICC and CV equaled 0.84 and 3.0%, respectively. The homogeneous sample of Australian footballers meant that the CODAT's TE (0.19 s exceeded the usual 0.2 x standard deviation (SD SWC (0.10 s. However, the CODAT is capable of detecting moderate performance changes (SWC calculated as 0.5 x SD = 0.25 s. There was a near perfect correlation between the CODAT and IAR (r = 0.92, and very large correlations with the 20-m sprint (r = 0.75-0.76, suggesting that the CODAT was a valid change-of-direction speed test. Due to movement specificity, the CODAT has value for field sport

  17. Bayes Analysis and Reliability Implications of Stress-Rupture Testing a Kevlar/Epoxy COPV Using Temperature and Pressure Acceleration

    Science.gov (United States)

    Phoenix, S. Leigh; Kezirian, Michael T.; Murthy, Pappu L. N.

    2009-01-01

    Composite Overwrapped Pressure Vessels (COPVs) that have survived a long service time under pressure generally must be recertified before service is extended. Flight certification is dependent on the reliability analysis to quantify the risk of stress rupture failure in existing flight vessels. Full certification of this reliability model would require a statistically significant number of lifetime tests to be performed and is impractical given the cost and limited flight hardware for certification testing purposes. One approach to confirm the reliability model is to perform a stress rupture test on a flight COPV. Currently, testing of such a Kevlar49 (Dupont)/epoxy COPV is nearing completion. The present paper focuses on a Bayesian statistical approach to analyze the possible failure time results of this test and to assess the implications in choosing between possible model parameter values that in the past have had significant uncertainty. The key uncertain parameters in this case are the actual fiber stress ratio at operating pressure, and the Weibull shape parameter for lifetime; the former has been uncertain due to ambiguities in interpreting the original and a duplicate burst test. The latter has been uncertain due to major differences between COPVs in the database and the actual COPVs in service. Any information obtained that clarifies and eliminates uncertainty in these parameters will have a major effect on the predicted reliability of the service COPVs going forward. The key result is that the longer the vessel survives, the more likely the more optimistic stress ratio model is correct. At the time of writing, the resulting effect on predicted future reliability is dramatic, increasing it by about one "nine," that is, reducing the predicted probability of failure by an order of magnitude. However, testing one vessel does not change the uncertainty on the Weibull shape parameter for lifetime since testing several vessels would be necessary.

  18. Study and implementation of a thermal acceleration test for the improvement of the quality and reliability of components and systems; Estudo e implementacao de um teste de aceleracao termica para a melhoria da qualidade e confiabilidade de componentes e sistemas

    Energy Technology Data Exchange (ETDEWEB)

    Leao, Felippe Carneiro

    1993-09-01

    The objective of this work is to introduce the application of the burn-in test (test of thermal acceleration) in electronic products, using the practical example of this test in a power supply and to do an analysis of the application of this test in a production line showing the advantages and disadvantages of its implementation. For that it is made an abbreviation presentation of the basic concepts of quality and reliability. Starting from these concepts are presented the statistical models used in reliability, that describe the behavior of life of products and components. Besides showing, from the speed chemical reaction model , the influence of the temperature about this reliability.

  19. CR reliability testing

    Science.gov (United States)

    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.

  20. Thermal reliability analysis of a BLDC motor in a high-speed axial fan by the accelerated-life test and numerical methods

    Science.gov (United States)

    Hur, Jin-Huek; Lee, Tae-Gu; Moon, Sun-Ae; Lee, Sang-Jae; Yoo, Hoseon; Moon, Seung-Jae; Lee, Jae-Heon

    2008-09-01

    The thermal reliability of a closed-type BLDC motor for a high-speed fan is analyzed by an accelerated-life testing and numerical methods in this paper. Since a module and a motor part are integrated in a closed case, heat generated from a rotor in a motor and electronic components in the PCB module cannot be effectively removed to the outside. Therefore, the module will easily fail due to high temperature. The experiment for measuring the temperature and the surface heat flux of the electronic components is carried out to predict their surface temperature distributions and main heat sources. The accelerated-life test is accomplished to formulate the life equation depending on the environmental temperature. Moreover, the temperature of the PCB module is different from the environmental temperature since the heat generated from the motor cannot be effectively dissipated owing to the motor’s structure. Therefore a numerical method is used to predict the temperature of the PCB module, which is one of the life equation parameter, according to the environment. By numerically obtaining the maxima of the thermal stress and strain of the electronic components according to the operation environments with the temperature results, the fatigue cycle can be estimated.

  1. A Comprehensive Review of Accelerated Life Test

    Institute of Scientific and Technical Information of China (English)

    ZHANG Chun-hua; WANG Ya-shun; CHEN Xun; WEN Xi-sen

    2005-01-01

    Accelerated life test (ALT) is an important branch of reliability test and is a focus of research both for statisticians and reliability engineers. The paper outlines the four topics of study embodied in ALT: statistical analysis of constant-stress test, step-stress test and progressive stress test, and optimal design of ALT. It gives a general review of engineering applications of ALT, and points out some possible directions in ALT, gives some suggestions for further study.

  2. Testing for PV Reliability (Presentation)

    Energy Technology Data Exchange (ETDEWEB)

    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.

  3. Testing Gravity on Accelerators

    CERN Document Server

    Kalaydzhyan, Tigran

    2016-01-01

    Weak equivalence principle (WEP) is one of the cornerstones of the modern theories of gravity, stating that the trajectory of a freely falling test body is independent of its internal structure and composition. Even though WEP is known to be valid for the normal matter with a high precision, it has never been experimentally confirmed for relativistic matter and antimatter. We make an attempt to constrain possible deviations from WEP utilizing the modern accelerator technologies. We analyze the (absence of) vacuum Cherenkov radiation, photon decay, anomalous synchrotron losses and the Compton spectra to put limits on the isotropic Lorentz violation and further convert them to the constraints on the difference between the gravitational and inertial masses of the relativistic electrons/positrons. Our main result is the 0.1% limit on the mentioned difference.

  4. Accelerated Testing of Solar Collector Durability

    DEFF Research Database (Denmark)

    Svendsen, Sv Aa Højgaard

    1996-01-01

    A climatic simulator has been build to test the reliability and durability of solar collectors. In the climatic simulator the collector is expåosed to extreme climatic conditions and temperature variations in an accelerated way and during this process the function of the collector is tested...... and the microclimate in the collector box is measured....

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

    CERN Document Server

    Willeke, F J

    2016-01-01

    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. The article closes with operational aspects of high reliability such as preventive maintenance and spares inventory.

  6. A Statistical Perspective on Highly Accelerated Testing

    Energy Technology Data Exchange (ETDEWEB)

    Thomas, Edward V. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States)

    2015-02-01

    Highly accelerated life testing has been heavily promoted at Sandia (and elsewhere) as a means to rapidly identify product weaknesses caused by flaws in the product's design or manufacturing process. During product development, a small number of units are forced to fail at high stress. The failed units are then examined to determine the root causes of failure. The identification of the root causes of product failures exposed by highly accelerated life testing can instigate changes to the product's design and/or manufacturing process that result in a product with increased reliability. It is widely viewed that this qualitative use of highly accelerated life testing (often associated with the acronym HALT) can be useful. However, highly accelerated life testing has also been proposed as a quantitative means for "demonstrating" the reliability of a product where unreliability is associated with loss of margin via an identified and dominating failure mechanism. It is assumed that the dominant failure mechanism can be accelerated by changing the level of a stress factor that is assumed to be related to the dominant failure mode. In extreme cases, a minimal number of units (often from a pre-production lot) are subjected to a single highly accelerated stress relative to normal use. If no (or, sufficiently few) units fail at this high stress level, some might claim that a certain level of reliability has been demonstrated (relative to normal use conditions). Underlying this claim are assumptions regarding the level of knowledge associated with the relationship between the stress level and the probability of failure. The primary purpose of this document is to discuss (from a statistical perspective) the efficacy of using accelerated life testing protocols (and, in particular, "highly accelerated" protocols) to make quantitative inferences concerning the performance of a product (e.g., reliability) when in fact there is lack-of-knowledge and uncertainty concerning

  7. A Statistical Perspective on Highly Accelerated Testing.

    Energy Technology Data Exchange (ETDEWEB)

    Thomas, Edward V.

    2015-02-01

    Highly accelerated life testing has been heavily promoted at Sandia (and elsewhere) as a means to rapidly identify product weaknesses caused by flaws in the product's design or manufacturing process. During product development, a small number of units are forced to fail at high stress. The failed units are then examined to determine the root causes of failure. The identification of the root causes of product failures exposed by highly accelerated life testing can instigate changes to the product's design and/or manufacturing process that result in a product with increased reliability. It is widely viewed that this qualitative use of highly accelerated life testing (often associated with the acronym HALT) can be useful. However, highly accelerated life testing has also been proposed as a quantitative means for "demonstrating" the reliability of a product where unreliability is associated with loss of margin via an identified and dominating failure mechanism. It is assumed that the dominant failure mechanism can be accelerated by changing the level of a stress factor that is assumed to be related to the dominant failure mode. In extreme cases, a minimal number of units (often from a pre-production lot) are subjected to a single highly accelerated stress relative to normal use. If no (or, sufficiently few) units fail at this high stress level, some might claim that a certain level of reliability has been demonstrated (relative to normal use conditions). Underlying this claim are assumptions regarding the level of knowledge associated with the relationship between the stress level and the probability of failure. The primary purpose of this document is to discuss (from a statistical perspective) the efficacy of using accelerated life testing protocols (and, in particular, "highly accelerated" protocols) to make quantitative inferences concerning the performance of a product (e.g., reliability) when in fact there is lack-of-knowledge and uncertainty concerning

  8. Accelerated Life Test Design for Tractor Powertrain Front Axle

    Directory of Open Access Journals (Sweden)

    Ismail Azianti

    2016-01-01

    Full Text Available Accelerated Life Test (ALT has been applied in the manufacturing for many years due to rapid changing technologies, more complex products, speedier product development, and more demanding customer requirements. These reasons have pushed the manufacturers to acquire reliability information faster. ALT allows reducing the time needed to show the reliability of the product. The purpose of this study is to design accelerated life testing which involved determination of normal test time, acceleration factor, acceleration test time, and finally experimental setup. This case study provides the basis for ALT designs for the tractor front axle based on customer usage and field failure analysis, which were conducted to estimate the current reliability, especially on the B10 life during the operational stage of the product. The accelerated life test conducted has guaranteed the B10 life of 4,000 hours with 90% confidence level for lesser time needed for testing to show the reliability of the front axle assembly.

  9. Advanced Superconducting Test Accelerator (ASTA)

    Data.gov (United States)

    Federal Laboratory Consortium — The Advanced Superconducting Test Accelerator (ASTA) facility will be based on upgrades to the existing NML pulsed SRF facility. ASTA is envisioned to contain 3 to 6...

  10. Advanced Superconducting Test Accelerator (ASTA)

    Data.gov (United States)

    Federal Laboratory Consortium — The Advanced Superconducting Test Accelerator (ASTA) facility will be based on upgrades to the existing NML pulsed SRF facility. ASTA is envisioned to contain 3 to...

  11. Importance, reliability and usefulness of acceleration measures in team sports.

    Science.gov (United States)

    Delaney, Jace A; Cummins, Cloe J; Thornton, Heidi R; Duthie, Grant M

    2017-02-08

    The ability to accelerate, decelerate and change direction efficiently is imperative to successful team-sports performance. Traditional intensity-based thresholds for acceleration and deceleration may be inappropriate for time-series data, and have been shown to exhibit poor reliability, suggesting other techniques may be preferable. This study assessed movement data from one professional rugby league team throughout two full seasons and one pre-season period. Using both 5 Hz and 10 Hz global positioning systems (GPS) units, a range of acceleration-based variables were evaluated for their inter-unit reliability, ability to discriminate between positions, and associations with perceived muscle soreness. The reliability of 5 Hz GPS for measuring acceleration and deceleration ranged from good to poor (CV = 3.7-27.1%), with the exception of high-intensity deceleration efforts (CV = 11.1-11.8%), the 10 Hz units exhibited moderate to good inter-unit reliability (CV = 1.2-6.9%). Reliability of average metrics (average acceleration/deceleration, average acceleration and average deceleration) ranged from good to moderate (CV = 1.2-6.5%). Substantial differences were detected between positions using time spent accelerating and decelerating for all magnitudes, but these differences were less clear when considering the count or distance above acceleration/deceleration thresholds. All average metrics detected substantial differences between positions. All measures were similarly related to perceived muscle soreness, with the exception of high-intensity acceleration and deceleration counts. This study has proposed that averaging the acceleration/deceleration demands over an activity may be a more appropriate method compared to threshold-based methods, due to a greater reliability between units, whilst not sacrificing sensitivity to within and between-subject changes.

  12. Terrestrial Photovoltaic Module Accelerated Test-To-Failure Protocol

    Energy Technology Data Exchange (ETDEWEB)

    Osterwald, C. R.

    2008-03-01

    This technical report documents a test-to-failure protocol that may be used to obtain quantitative information about the reliability of photovoltaic modules using accelerated testing in environmental temperature-humidity chambers.

  13. Accelerated Wafer-Level Integrated Circuit Reliability Testing for Electromigration in Metal Interconnects with Enhanced Thermal Modeling, Structure Design, Control of Stress, and Experimental Measurements.

    Science.gov (United States)

    Shih, Chih-Ching

    Wafer-level electromigration tests have been developed recently to fulfill the need for rapid testing in integrated circuit production facilities. We have developed an improved thermal model-TEARS (Thermal Energy Accounts for the Resistance of the System) that supports these tests. Our model is enhanced by treatments for determination of the thermal conductivity of metal, K_{m}, heat sinking effects of the voltage probes and current lead terminations, and thermoelectric power. Our TEARS analysis of multi-element SWEAT (Standard Wafer-level Electromigration Acceleration Test) structures yields design criteria for the length of current injection leads and choice of voltage probe locations to isolate test units from the heat sinking effect of current lead terminations. This also provides greater insight into the current for thermal runaway. From our TEARS model and Black's equation for lifetime prediction, we have developed an algorithm for a fast and accurate control of stress in SWEAT tests. We have developed a lookup table approach for precise electromigration characterizations without complicated calculations. It decides the peak temperature in the metal, T_ {max}, and the thermal conductivity of the insulator, K_{i}, from an experimental resistance measurement at a given current. We introduce a characteristic temperature, T _{EO}, which is much simpler to use than conventional temperature coefficient of the electrical resistivity of metal for calibration and transfer of calibration data of metallic films as their own temperature sensors. The use of T_{EO} also allows us to establish system specifications for a desirable accuracy in temperature measurement. Our experimental results are the first to show the effects of series elemental SWEAT units on the system failure distribution, spatial failure distribution in SWEAT structures, and bimodal distributions for straight-line structures. The adaptive approach of our TEARS based SWEAT test decides the value of Black

  14. Tractor accelerated test on test rig

    Directory of Open Access Journals (Sweden)

    M. Mattetti

    2013-09-01

    Full Text Available The experimental tests performed to validate a tractor prototype before its production, need a substantial financial and time commitment. The tests could be reduced using accelerated tests able to reproduce on the structural part of the tractor, the same damage produced on the tractor during real life in a reduced time. These tests were usually performed reproducing a particular harsh condition a defined number of times, as for example using a bumpy road on track to carry out the test in any weather condition. Using these procedures the loads applied on the tractor structure are different with respect to those obtained during the real use, with the risk to apply loads hard to find in reality. Recently it has been demonstrated how, using the methodologies designed for cars, it is possible to also expedite the structural tests for tractors. In particular, automotive proving grounds were recently successfully used with tractors to perform accelerated structural tests able to reproduce the real use of the machine with an acceleration factor higher than that obtained with the traditional methods. However, the acceleration factor obtained with a tractor on proving grounds is in any case reduced due to the reduced speed of the tractors with respect to cars. In this context, the goal of the paper is to show the development of a methodology to perform an accelerated structural test on a medium power tractor using a 4 post test rig. In particular, several proving ground testing conditions have been performed to measure the loads on the tractor. The loads obtained were then edited to remove the not damaging portion of signals, and finally the loads obtained were reproduced in a 4 post test rig. The methodology proposed could be a valid alternative to the use of a proving ground to reproduce accelerated structural tests on tractors.

  15. Accelerated Life Test Design for Tractor Powertrain Front Axle

    OpenAIRE

    2016-01-01

    Accelerated Life Test (ALT) has been applied in the manufacturing for many years due to rapid changing technologies, more complex products, speedier product development, and more demanding customer requirements. These reasons have pushed the manufacturers to acquire reliability information faster. ALT allows reducing the time needed to show the reliability of the product. The purpose of this study is to design accelerated life testing which involved determination of normal test time, accelera...

  16. Weibull分布对数线性加速模型的可靠性估计方法%Reliability Estimation for Weibull Log-linear Accelerated Life Testing Model

    Institute of Scientific and Technical Information of China (English)

    刘婷

    2011-01-01

    Accelerated life tests,in which more than one stress is often involved, have become widely used in today's industries. The log-linear accelerated model was proposed to describe the relation between multiple-stress and product's lifetime, and Weibull log-linear accelerated models were established. Due to highly nonlinear and non-monotonic of the log likelihood function, the genetic algorithm could be adopted to determine the maximum likelihood estimates of accelerated model parameters, and then reliability assessment and lifetime prediction could be realized under various stress. Finally,simulation results illustrate reasonability of the method proposed in the paper.%针对Weibull分布产品的多应力加速试验,提出采用对数线性加速模型描述多个应力和产品寿命之间的定量关系,建立了Weibull分布对数线性加速试验的可靠性分析模型.鉴于似然函数的高度非线性和非单调特性,采用遗传算法得到了加速模型参数的极大似然估计,可以实现不同应力之间可靠性特性参数的相互转换.仿真算例验证了所提方法的有效性.

  17. Quantitative Accelerated Life Testing of MEMS Accelerometers

    Directory of Open Access Journals (Sweden)

    Jean-Paul Collette

    2007-11-01

    Full Text Available Quantitative Accelerated Life Testing (QALT is a solution for assessing thereliability of Micro Electro Mechanical Systems (MEMS. A procedure for QALT is shownin this paper and an attempt to assess the reliability level for a batch of MEMSaccelerometers is reported. The testing plan is application-driven and contains combinedtests: thermal (high temperature and mechanical stress. Two variants of mechanical stressare used: vibration (at a fixed frequency and tilting. Original equipment for testing at tiltingand high temperature is used. Tilting is appropriate as application-driven stress, because thetilt movement is a natural environment for devices used for automotive and aerospaceapplications. Also, tilting is used by MEMS accelerometers for anti-theft systems. The testresults demonstrated the excellent reliability of the studied devices, the failure rate in the“worst case” being smaller than 10-7h-1.

  18. Reliability assessment for metallized film pulse capacitors with accelerated degradation test%加速退化试验下金属化膜脉冲电容器可靠性评估

    Institute of Scientific and Technical Information of China (English)

    赵建印; 刘芳; 奚文骏; 贺少勃; 魏晓峰

    2011-01-01

    The high energy density self-healing metallized film pulse capacitor has been applied to all kinds of laser facilities for their power conditioning systems, whose reliability is straightforward affected by the reliability level of capacitors. Reliability analysis of highly reliable devices, such as metallized film capacitors, is a challenge due to cost and time restriction. Accelerated degradation test provides a way to predict its life cost and time effectively. A model and analyses for accelerated degradation data of metallized film capacitors are described. Also described is a method for estimating the distribution of failure time. The estimation values of the unknown parameters in this model are 9. 066 9× 10-8 and 0. 022 1. Both the failure probability density function (PDF) and the cumulative distribution function (CDF) can be presented by this degradation failure model. Based on these estimation values and the PDF/CDF, the reliability model of the metallized film capacitors is obtained. According to the reliability model, the probability of the capacitors surviving to 20 000 shot is 0. 972 4.%分析了金属化膜脉冲电容器的失效机理.根据金属化膜脉冲电容器加速退化数据,研究了其可靠性评价问题.基于疲劳失效的Birnbaum-Saunders模型,建立电容器失效分布函数.根据试验数据可求得该型电容器可靠性模型中参数估计值,并将该值代入失效分布函数即可确定电容器的失效模型,求得该型电容器充放电20 000次的可靠度为0.972 4.使用这种分析方式对金属化膜脉冲电容器进行可靠性分析将更能节省试验时间和费用.

  19. Quantitative accelerated degradation testing: Practical approaches

    Energy Technology Data Exchange (ETDEWEB)

    Mohammadian, S. Hossein, E-mail: seyed-h.mohammadian.1@ulaval.c [Centre Interuniversitaire de Recherche sur les Reseaux d' Entreprise, la Logistique et le Transport (CIRRELT), Departement de Genie Mecanique, Pavillon Adrien-Pouliot, Universite Laval, Quebec, G1V 0A6 (Canada) and Centre Interdisciplinaire de Recherche en Readaptation et en Integration Sociale (CIRRIS), Institut de Readaptation en Deficience Physique de Quebec, 525 Boul. Hamel, Quebec, G1M 2S8 (Canada); Ait-Kadi, Daoud, E-mail: Daoud.Aitkadi@gmc.ulaval.c [Centre Interuniversitaire de Recherche sur les Reseaux d' Entreprise, la Logistique et le Transport (CIRRELT), Departement de Genie Mecanique, Pavillon Adrien-Pouliot, Universite Laval, Quebec, G1V 0A6 (Canada); Centre Interdisciplinaire de Recherche en Readaptation et en Integration Sociale (CIRRIS), Institut de Readaptation en Deficience Physique de Quebec, 525 Boul. Hamel, Quebec, G1M 2S8 (Canada); Routhier, Francois, E-mail: Francois.Routhier@rea.ulaval.c [Centre Interdisciplinaire de Recherche en Readaptation et en Integration Sociale (CIRRIS), Institut de Readaptation en Deficience Physique de Quebec, 525 Boul. Hamel, Quebec, G1M 2S8 (Canada)

    2010-02-15

    The concept of accelerated testing by tracking degradation of samples over test time needs to be developed for reliability estimation. This paper aims at proposing practical approaches to conduct accelerated degradation testing on new and available used samples. For this purpose, product failure is related to a suitable physical property. Then, its failure time is defined as the expected time in which its property reaches the critical level. Degradation model of field samples returned from service due to a degrading failure mode has been estimated based on the least square method, and available gap between manufacturer criterion and user's claim (to report a failure) has also been discussed. For a product under some stresses, a general formula has been proposed by the superposition principle in order to estimate its degradation for independent and dependent failure modes. If used samples are available, and acceleration factor of the related test is unknown, partial aging method has been presented to considerably shorten the test time.

  20. Reliability Approach for Machine Protection Design in Particle Accelerators

    CERN Document Server

    Apollonio, A; Mikulec, B; Puccio, B; Sanchez Alvarez, J L; Schmidt, R; Wagner, S

    2013-01-01

    Particle accelerators require Machine Protection Systems (MPS) to prevent beam-induced damage of equipment in case of failures. This becomes increasingly important for proton colliders with large energy stored in the beam such as LHC, for high power accelerators with a beam power of up to 10 MW, such as the European Spallation Source (ESS), and for linear colliders with high beam power and very small beam size. The reliability of Machine Protection Systems is crucial for safe machine operation; all possible sources of risk need to be taken into account in the early design stage. This paper presents a systematic approach to classify failures and to assess the associated risk, and discusses the impact of such considerations on the design of Machine Protection Systems. The application of this approach will be illustrated using the new design of the MPS for LINAC4, a linear accelerator under construction at CERN.

  1. Predicting edge seal performance from accelerated testing

    Science.gov (United States)

    Hardikar, Kedar; Vitkavage, Dan; Saproo, Ajay; Krajewski, Todd

    2014-10-01

    Degradation in performance of a PV module attributable to moisture ingress has received significant attention in PV reliability research. Assessment of field performance of PV modules against moisture ingress through product-level testing in temperature-humidity control chambers poses challenges. Development of a meaningful acceleration factor model is challenging due to different rates of degradation of components embedded in a PV module, when exposed to moisture. Test results are typically a convolution of moisture barrier performance of the edge seal and degradation of laminated components when exposed to moisture. It is desirable to have an alternate method by which moisture barrier performance of the edge seal in its end product form can be assessed in any given field conditions, independent of particular cell design. In this work, a relatively inexpensive test technique was developed to test the edge seal in its end product form in a manner that is decoupled from other components of the PV module. A theoretical framework was developed to assess moisture barrier performance of edge seal with desiccants subjected to different conditions. This framework enables the analysis of test results from accelerated tests and prediction of the field performance of the edge seal. Results from this study lead to the conclusion that the edge seal on certain Miasole glass-glass modules studied is effective for the most aggressive weather conditions examined, beyond the intended service.

  2. 一种新的恒加试验下双参数指数型产品的可靠性分析%Reliability Analysis for Two-parameter Exponential Unit under Content-stress Accelerated Life Test

    Institute of Scientific and Technical Information of China (English)

    谭伟; 师义民; 孙玉东

    2012-01-01

    针对双参数指数型产品,在具有二项移走(即在每个观测时刻产品的移走数服从二项分布)的分组寿命试验下,研究了分组时刻的确定方法,推导出门限参数、寿命参数和移走概率的极大似然估计。进而,讨论了双参数指数型产品在具有二项移走的恒加寿命分组试验下的可靠性分析问题。利用加速寿命方程,给出了双参数指数型产品的可靠性估计。最后给出随机模拟例子验证了结论的正确性。%Based on two-parameter exponential grouped life test with binomial removals (The number of samples removed obey the binomial distribution at each observation time), the paper studied the method to determine the grouped time, derived out and removal probability. Then, under the situation the MLE of threshold parameter, lifetime parameter of constant-stress accelerated grouped life test with binomial removals, by the aid of the accelerated life equation, the paper gave out the reliability estimation of two-parameter exponential unit. Finally, simulation example is given to verify the correctness of the result.

  3. Accelerated tests of coil coatings

    Directory of Open Access Journals (Sweden)

    Rosales, B. M.

    2003-12-01

    Full Text Available Accelerated laboratory tests on 12 materials in study in the Subgroup 6 of the PATINA Network (CYTED, are discussed for different exposition periods in salt spray, SO2 and Prohesion chambers. International standards used to evaluate failures caused by the different aggressive agents of these laboratory tests are the same as those applied for outdoor expositions. The results exposed contribute to a better understanding of the mechanisms occurred in the diverse natural environments, being mentioned the main analogies and differences respect to factors affecting natural tests. They also allowed to evidence the advantages and limitations in the application of these tests during several days, as compared to the years required to attain similar failure magnitudes through outdoor tests.

    En este trabajo se discuten los ensayos de laboratorio acelerados, realizados sobre 12 materiales de estudio en el Subgrupo 6 de la Red PATINA (CYTED, a diferentes periodos de exposición en cámaras de niebla salina, SO2 y Prohesion. Se utilizaron las normas internacionales para evaluar los fallos causados por los diferentes agentes agresivos de estos ensayos de laboratorio, las cuales se aplican también para los ensayos de exposición a la intemperie. Los resultados expuestos contribuyen a una mejor comprensión de los mecanismos ocurridos en los diversos ambientes naturales, mencionándose las principales analogías y diferencias respecto de los factores que afectan los ensayos naturales. También permitieron evidenciar las ventajas y limitaciones en la aplicación de estos ensayos durante varios días, en comparación con los años requeridos para alcanzar magnitudes de fallos similares por medio de ensayos a intemperie.

  4. Test-retest reliability of trunk accelerometric gait analysis

    DEFF Research Database (Denmark)

    Henriksen, Marius; Lund, Hans; Moe-Nilssen, R

    2004-01-01

    The purpose of this study was to determine the test-retest reliability of a trunk accelerometric gait analysis in healthy subjects. Accelerations were measured during walking using a triaxial accelerometer mounted on the lumbar spine of the subjects. Six men and 14 women (mean age 35.2; range 18...

  5. Modeling Reliability Growth in Accelerated Stress Testing

    Science.gov (United States)

    2013-12-01

    projection models for both continuous use and discrete use systems found anywhere in the literature. The review comprises a synopsis of over 80...pertaining to the research that may have been unfamiliar to the reader. The Chapter has provided a synopsis of the research accomplished in the fields of...Cox, "Analysis of the probability and risk of cause specific failure," International Journal of Radiology Oncology, Biology, Physics, vol. 29, no. 5

  6. Accelerated testing statistical models, test plans, and data analysis

    CERN Document Server

    Nelson, Wayne B

    2009-01-01

    The Wiley-Interscience Paperback Series consists of selected books that have been made more accessible to consumers in an effort to increase global appeal and general circulation. With these new unabridged softcover volumes, Wiley hopes to extend the lives of these works by making them available to future generations of statisticians, mathematicians, and scientists. "". . . a goldmine of knowledge on accelerated life testing principles and practices . . . one of the very few capable of advancing the science of reliability. It definitely belongs in every bookshelf on engineering.""-Dev G.

  7. Accelerators for Fusion Materials Testing

    Science.gov (United States)

    Knaster, Juan; Okumura, Yoshikazu

    Fusion materials research is a worldwide endeavor as old as the parallel one working toward the long term stable confinement of ignited plasma. In a fusion reactor, the preservation of the required minimum thermomechanical properties of the in-vessel components exposed to the severe irradiation and heat flux conditions is an indispensable factor for safe operation; it is also an essential goal for the economic viability of fusion. Energy from fusion power will be extracted from the 14 MeV neutron freed as a product of the deuterium-tritium fusion reactions; thus, this kinetic energy must be absorbed and efficiently evacuated and electricity eventually generated by the conventional methods of a thermal power plant. Worldwide technological efforts to understand the degradation of materials exposed to 14 MeV neutron fluxes >1018 m-2s-1, as expected in future fusion power plants, have been intense over the last four decades. Existing neutron sources can reach suitable dpa (“displacement-per-atom”, the figure of merit to assess materials degradation from being exposed to neutron irradiation), but the differences in the neutron spectrum of fission reactors and spallation sources do not allow one to unravel the physics and to anticipate the degradation of materials exposed to fusion neutrons. Fusion irradiation conditions can be achieved through Li (d, xn) nuclear reactions with suitable deuteron beam current and energy, and an adequate flowing lithium screen. This idea triggered in the late 1970s at Los Alamos National Laboratory (LANL) a campaign working toward the feasibility of continuous wave (CW) high current linacs framed by the Fusion Materials Irradiation Test (FMIT) project. These efforts continued with the Low Energy Demonstrating Accelerator (LEDA) (a validating prototype of the canceled Accelerator Production of Tritium (APT) project), which was proposed in 2002 to the fusion community as a 6.7MeV, 100mA CW beam injector for a Li (d, xn) source to bridge

  8. How Reliable Is Laboratory Testing?

    Science.gov (United States)

    Advertisement Proceeds from website advertising help sustain Lab Tests Online. AACC is a not-for-profit organization and does not endorse non-AACC products and services. Advertising & Sponsorship: Policy | Opportunities ...

  9. Advanced Test Accelerator (ATA) pulse power technology development

    Energy Technology Data Exchange (ETDEWEB)

    Reginato, L.L.; Branum, D.; Cook, E.

    1981-03-09

    The Advanced Test Accelerator (ATA) is a pulsed linear induction accelerator with the following design parameters: 50 MeV, 10 kA, 70 ns, and 1 kHz in a ten-pulse burst. Acceleration is accomplished by means of 190 ferrite-loaded cells, each capable of maintaining a 250 kV voltage pulse for 70 ns across a 1-inch gap. The unique characteristic of this machine is its 1 kHz burst mode capability at very high currents. This paper dscribes the pulse power development program which used the Experimental Test Accelerator (ETA) technology as a starting base. Considerable changes have been made both electrically and mechanically in the pulse power components with special consideration being given to the design to achieve higher reliability. A prototype module which incorporates all the pulse power components has been built and tested for millions of shots. Prototype components and test results are described.

  10. Accelerated life testing effects on CMOS microcircuit characteristics, phase 1

    Science.gov (United States)

    Maximow, B.

    1976-01-01

    An accelerated life test of sufficient duration to generate a minimum of 50% cumulative failures in lots of CMOS devices was conducted to provide a basis for determining the consistency of activation energy at 250 C. An investigation was made to determine whether any thresholds were exceeded during the high temperature testing, which could trigger failure mechanisms unique to that temperature. The usefulness of the 250 C temperature test as a predictor of long term reliability was evaluated.

  11. DARHT II Scaled Accelerator Tests on the ETA II Accelerator*

    Energy Technology Data Exchange (ETDEWEB)

    Weir, J T; Anaya Jr, E M; Caporaso, G J; Chambers, F W; Chen, Y; Falabella, S; Lee, B S; Paul, A C; Raymond, B A; Richardson, R A; Watson, J A; Chan, D; Davis, H A; Day, L A; Scarpetti, R D; Schultze, M E; Hughes, T P

    2005-05-26

    The DARHT II accelerator at LANL is preparing a series of preliminary tests at the reduced voltage of 7.8 MeV. The transport hardware between the end of the accelerator and the final target magnet was shipped to LLNL and installed on ETA II. Using the ETA II beam at 5.2 MeV we completed a set of experiments designed reduce start up time on the DARHT II experiments and run the equipment in a configuration adapted to the reduced energy. Results of the beam transport using a reduced energy beam, including the kicker and kicker pulser system will be presented.

  12. Testing general relativity on accelerators

    Directory of Open Access Journals (Sweden)

    Tigran Kalaydzhyan

    2015-11-01

    Full Text Available Within the general theory of relativity, the curvature of spacetime is related to the energy and momentum of the present matter and radiation. One of the more specific predictions of general relativity is the deflection of light and particle trajectories in the gravitational field of massive objects. Bending angles for electromagnetic waves and light in particular were measured with a high precision. However, the effect of gravity on relativistic massive particles was never studied experimentally. Here we propose and analyze experiments devoted to that purpose. We demonstrate a high sensitivity of the laser Compton scattering at high energy accelerators to the effects of gravity. The main observable – maximal energy of the scattered photons – would experience a significant shift in the ambient gravitational field even for otherwise negligible violation of the equivalence principle. We confirm predictions of general relativity for ultrarelativistic electrons of energy of tens of GeV at a current level of resolution and expect our work to be a starting point of further high-precision studies on current and future accelerators, such as PETRA, European XFEL and ILC.

  13. Testing general relativity on accelerators

    CERN Document Server

    Kalaydzhyan, Tigran

    2015-01-01

    Within the general theory of relativity, the curvature of spacetime is related to the energy and momentum of the present matter and radiation. One of the more specific predictions of general relativity is the deflection of light and particle trajectories in the gravitational field of massive objects. Bending angles for electromagnetic waves and light in particular were measured with a high precision. However, the effect of gravity on relativistic massive particles was never studied experimentally. Here we propose and analyse experiments devoted to that purpose. We demonstrate a high sensitivity of the laser Compton scattering at high energy accelerators to the effects of gravity. The main observable -- maximal energy of the scattered photons -- would experience a significant shift in the Earth's gravitational field even for otherwise negligible violation of the equivalence principle. We confirm predictions of general relativity for ultrarelativistic electrons of energy of tens of GeV at a current level of res...

  14. Conditional Reliability Coefficients for Test Scores.

    Science.gov (United States)

    Nicewander, W Alan

    2017-04-06

    The most widely used, general index of measurement precision for psychological and educational test scores is the reliability coefficient-a ratio of true variance for a test score to the true-plus-error variance of the score. In item response theory (IRT) models for test scores, the information function is the central, conditional index of measurement precision. In this inquiry, conditional reliability coefficients for a variety of score types are derived as simple transformations of information functions. It is shown, for example, that the conditional reliability coefficient for an ordinary, number-correct score, X, is equal to, ρ(X,X'|θ)=I(X,θ)/[I(X,θ)+1] Where: θ is a latent variable measured by an observed test score, X; p(X, X'|θ) is the conditional reliability of X at a fixed value of θ; and I(X, θ) is the score information function. This is a surprisingly simple relationship between the 2, basic indices of measurement precision from IRT and classical test theory (CTT). This relationship holds for item scores as well as test scores based on sums of item scores-and it holds for dichotomous as well as polytomous items, or a mix of both item types. Also, conditional reliabilities are derived for computerized adaptive test scores, and for θ-estimates used as alternatives to number correct scores. These conditional reliabilities are all related to information in a manner similar-or-identical to the 1 given above for the number-correct (NC) score. (PsycINFO Database Record (c) 2017 APA, all rights reserved).

  15. Photovoltaic reliability engineering: quantification testing and probabilistic-design-reliability concept

    Science.gov (United States)

    Suhir, Ephraim; Bechou, Laurent; Bensoussan, Alain; Nicolics, Johann

    2013-09-01

    Qualification testing (QT) is the major means for making a viable photovoltaic (PV) device into a reliable and marketable product. It is well known, however, that the today's PV modules (PVM) that passed the existing QT often exhibit premature field failures. Could the existing QT specifications and testing procedures be improved to an extent that if a PV device, module or a system passed the QT, there is a quantifiable and consistent way to assure that its performance in the field will be satisfactory and that its projected lifetime will indeed take place with the given confidence? The application of the probabilistic design for reliability (PDfR) concept enables one to provide an affirmative answer to this question. The attributes and challenges of this concept and the roles of its major constituents - failure oriented accelerated testing (FOAT) and physically meaningful predictive modeling (PM) - are addressed and discussed in detail.

  16. Reliability of segmental accelerations measured using a new wireless gait analysis system.

    Science.gov (United States)

    Kavanagh, Justin J; Morrison, Steven; James, Daniel A; Barrett, Rod

    2006-01-01

    The purpose of this study was to determine the inter- and intra-examiner reliability, and stride-to-stride reliability, of an accelerometer-based gait analysis system which measured 3D accelerations of the upper and lower body during self-selected slow, preferred and fast walking speeds. Eight subjects attended two testing sessions in which accelerometers were attached to the head, neck, lower trunk, and right shank. In the initial testing session, two different examiners attached the accelerometers and performed the same testing procedures. A single examiner repeated the procedure in a subsequent testing session. All data were collected using a new wireless gait analysis system, which features near real-time data transmission via a Bluetooth network. Reliability for each testing condition (4 locations, 3 directions, 3 speeds) was quantified using a waveform similarity statistic known as the coefficient of multiple determination (CMD). CMD's ranged from 0.60 to 0.98 across all test conditions and were not significantly different for inter-examiner (0.86), intra-examiner (0.87), and stride-to-stride reliability (0.86). The highest repeatability for the effect of location, direction and walking speed were for the shank segment (0.94), the vertical direction (0.91) and the fast walking speed (0.91), respectively. Overall, these results indicate that a high degree of waveform repeatability was obtained using a new gait system under test-retest conditions involving single and dual examiners. Furthermore, differences in acceleration waveform repeatability associated with the reapplication of accelerometers were small in relation to normal motor variability.

  17. High-Voltage Terminal Test of Test Stand for 1-MV Electrostatic Accelerator

    CERN Document Server

    Park, Sae-Hoon

    2015-01-01

    The Korea Multipurpose Accelerator Complex (KOMAC) has been developing a 300-kV test stand for a 1-MV electrostatic accelerator ion source. The ion source and accelerating tube will be installed in a high-pressure vessel. The ion source in the high-pressure vessel is required to have a high reliability. The test stand has been proposed and developed to confirm the stable operating conditions of the ion source. The ion source will be tested at the test stand to verify the long-time operating conditions. The test stand comprises a 300-kV high-voltage terminal, a battery for the ion-source power, a 60-Hz inverter, 200-MHz RF power, a 5-kV extraction power supply, a 300-kV accelerating tube, and a vacuum system. The results of the 300-kV high-voltage terminal tests are presented in this paper.

  18. Reliability Testing Procedure for MEMS IMUs Applied to Vibrating Environments

    Directory of Open Access Journals (Sweden)

    Aurelio Somà

    2010-01-01

    Full Text Available The diffusion of micro electro-mechanical systems (MEMS technology applied to navigation systems is rapidly increasing, but currently, there is a lack of knowledge about the reliability of this typology of devices, representing a serious limitation to their use in aerospace vehicles and other fields with medium and high requirements. In this paper, a reliability testing procedure for inertial sensors and inertial measurement units (IMU based on MEMS for applications in vibrating environments is presented. The sensing performances were evaluated in terms of signal accuracy, systematic errors, and accidental errors; the actual working conditions were simulated by means of an accelerated dynamic excitation. A commercial MEMS-based IMU was analyzed to validate the proposed procedure. The main weaknesses of the system have been localized by providing important information about the relationship between the reliability levels of the system and individual components.

  19. Investigation of reliability attributes and accelerated stress factors of terrestrial solar cells. First annual report

    Energy Technology Data Exchange (ETDEWEB)

    Prince, J.L.; Lathrop, J.W.

    1979-05-01

    The results of accelerated stress testing of four different types of silicon terrestrial solar cells are discussed. The accelerated stress tests used included bias-temperature tests, bias-temperature-humidity tests, thermal cycle and thermal shock tests, and power cycle tests. Characterization of the cells was performed before stress testing and at periodic down-times, using electrical measurement, visual inspection, and metal adherence pull tests. Electrical parameters measured included short-circuit current, I/sub sc/, open circuit voltage, V/sub oc/, and output power, voltage, and current at the maximum power point, P/sub m/, V/sub m/, and I/sub m/ respectively. Incorporated in the report are the distributions of the prestress electrical data for all cell types. Data was also obtained on cell series and shunt resistance. Significant differences in the response to the various stress tests was observed between cell types. On the basis of the experience gained in this research work, a suggested Reliability Qualification Test Schedule was developed.

  20. Reliability test and failure analysis of high power LED packages*

    Institute of Scientific and Technical Information of China (English)

    Chen Zhaohui; Zhang Qin; Wang Kai; Luo Xiaobing; Liu Sheng

    2011-01-01

    A new type application specific light emitting diode (LED) package (ASLP) with freeform polycarbonate lens for street lighting is developed, whose manufacturing processes are compatible with a typical LED packaging process. The reliability test methods and failure criterions from different vendors are reviewed and compared. It is found that test methods and failure criterions are quite different. The rapid reliability assessment standards are urgently needed for the LED industry. 85 ℃/85 RH with 700 mA is used to test our LED modules with three other vendors for 1000 h, showing no visible degradation in optical performance for our modules, with two other vendors showing significant degradation. Some failure analysis methods such as C-SAM, Nano X-ray CT and optical microscope are used for LED packages. Some failure mechanisms such as delaminations and cracks are detected in the LED packages after the accelerated reliability testing. The finite element simulation method is helpful for the failure analysis and design of the reliability of the LED packaging. One example is used to show one currently used module in industry is vulnerable and may not easily pass the harsh thermal cycle testing.

  1. Accelerated propor tional degradation hazards-odds model in accelerated degradation test

    Institute of Scientific and Technical Information of China (English)

    Tingting Huang; Zhizhong Li

    2015-01-01

    An accelerated proportional degradation hazards-odds model is proposed. It is a non-parametric model and thus has path-free and distribution-free properties, avoiding the errors caused by faulty assumptions of degradation paths or distribution of degra-dation measurements. It is established based on a link function which combines the degradation cumulative hazard rate function and the degradation odds function through a transformation pa-rameter, and this makes the accelerated proportional degradation hazards model and the accelerated proportional degradation odds model special cases of it. Hypothesis tests are discussed, and the proposed model is applicable when some model assumptions are satisfied. This model is utilized to estimate the reliability of minia-ture bulbs under low stress levels based on the degradation data obtained under high stress levels to validate the effectiveness of this model.

  2. Analysis of Transmitted Optical Spectrum Enabling Accelerated Testing of CPV Designs: Preprint

    Energy Technology Data Exchange (ETDEWEB)

    Miller, D. C.; Kempe, M. D.; Kennedy, C. E.; Kurtz, S. R.

    2009-07-01

    Reliability of CPV systems' materials is not well known; methods for accelerated UV testing have not been developed. UV and IR spectra transmitted through representative optical systems are evaluated.

  3. Study on Accelerated Life Testing Technology and the Researches for Highly Reliable Components%高可靠产品加速寿命试验技术及其相关研究

    Institute of Scientific and Technical Information of China (English)

    葛莉; 马志宏

    2013-01-01

      Relative concepts of accelerated life testing (ALT) are briefly introduced in this paper. The experiment design and statistical analysis about three types of accelerated life testing are given and also the researches in this field are also presented. Some methods of optimal design for ALT are given. The possible directions for further researches in ALT are advanced in the end.%  本文介绍了加速寿命试验技术的有关概念,概括总结了三种类型加速寿命试验的试验设计和统计分析,阐述了该技术的相关研究内容,提出了加速寿命试验技术优化设计方面的方法,最后指出了一些可以继续研究的相关内容。

  4. SMART empirical approaches for predicting field performance of PV modules from results of reliability tests

    Science.gov (United States)

    Hardikar, Kedar Y.; Liu, Bill J. J.; Bheemreddy, Venkata

    2016-09-01

    Gaining an understanding of degradation mechanisms and their characterization are critical in developing relevant accelerated tests to ensure PV module performance warranty over a typical lifetime of 25 years. As newer technologies are adapted for PV, including new PV cell technologies, new packaging materials, and newer product designs, the availability of field data over extended periods of time for product performance assessment cannot be expected within the typical timeframe for business decisions. In this work, to enable product design decisions and product performance assessment for PV modules utilizing newer technologies, Simulation and Mechanism based Accelerated Reliability Testing (SMART) methodology and empirical approaches to predict field performance from accelerated test results are presented. The method is demonstrated for field life assessment of flexible PV modules based on degradation mechanisms observed in two accelerated tests, namely, Damp Heat and Thermal Cycling. The method is based on design of accelerated testing scheme with the intent to develop relevant acceleration factor models. The acceleration factor model is validated by extensive reliability testing under different conditions going beyond the established certification standards. Once the acceleration factor model is validated for the test matrix a modeling scheme is developed to predict field performance from results of accelerated testing for particular failure modes of interest. Further refinement of the model can continue as more field data becomes available. While the demonstration of the method in this work is for thin film flexible PV modules, the framework and methodology can be adapted to other PV products.

  5. Manufacturing and Testing of Accelerator Superconducting Magnets

    CERN Document Server

    Rossi, L

    2014-01-01

    Manufacturing of superconducting magnet for accelerators is a quite complex process that is not yet fully industrialized. In this paper, after a short history of the evolution of the magnet design and construction, we review the main characteristics of the accelerator magnets having an impact on the construction technology. We put in evidence how the design and component quality impact on construction and why the final product calls for a total-quality approach. LHC experience is widely discussed and main lessons are spelled out. Then the new Nb3Sn technology, under development for the next generation magnet construction, is outlined. Finally, we briefly review the testing procedure of accelerator superconducting magnets, underlining the close connection with the design validation and with the manufacturing process.

  6. Reliability of novel postural sway task test

    Directory of Open Access Journals (Sweden)

    Milan Sedliak

    2013-07-01

    Full Text Available The purpose of this study was to examine the reliability of parameters obtained from a novel postural sway task test based on body movements controlled by visual feedback. Fifty-nine volunteers were divided into two groups. The first group consisted of young (n = 32, 16 females and 16 males, age: 25.2 ± 3.4 years and the second group of elderly individuals (n = 27, 17 females and 10 males, age: 75.7 ± 6.9 years. Participants stood in parallel on a computer based stabilographic platform with the feet approximately a shoulder width apart, the toes slightly pointing outwards, the hands placed on the hips. The computer screen was placed approximately 1.5 meter from the platform at a height of subjects’ eyes. An instantaneous visual feedback of participant’s centre of pressure (COP was given in a form of a blue cross visible on the screen. Participants were instructed to keep the blue cross driven by movements of their hips as close as possible to a predefined curve flowing on the screen. Out of the 6 parameters studied, only the average distance of COP from the curve line and the sum of the COP crossings through the curve line showed high reliability. Correlation between these two highly reliable parameters was -0.89. There was also a statistical difference (p<0.001 between young and elderly in both the average distance of COP from the curve line and the sum of the COP crossings through the curve. To conclude, the novel postural sway task provides a simple tool with relatively low time burden needed for testing. The suggested output parameters measured are highly reliable and easy to interpret.

  7. The macular mapping test: a reliability study

    Directory of Open Access Journals (Sweden)

    Davies Leon N

    2005-08-01

    Full Text Available Abstract Background Age-related macular degeneration (ARMD is the leading cause of visual disability in people over 60 years of age in the developed world. The success of treatment deteriorates with increased latency of diagnosis. The purpose of this study was to determine the reliability of the macular mapping test (MMT, and to investigate its potential as a screening tool. Methods The study population comprised of 31 healthy eyes of 31 participants. To assess reliability, four macular mapping test (MMT measurements were taken in two sessions separated by one hour by two practitioners, with reversal of order in the second session. MMT readings were also taken from 17 age-related maculopathy (ARM, and 12 AMD affected eyes. Results For the normal cohort, average MMT scores ranged from 85.5 to 100.0 MMT points. Scores ranged from 79.0 to 99.0 for the ARM group and from 9.0 to 92.0 for the AMD group. MMT scores were reliable to within ± 7.0 points. The difference between AMD affected eyes and controls (z = 3.761, p = Conclusion The reliability data shows that a change of 14 points or more is required to indicate a clinically significant change. This value is required for use of the MMT as an outcome measure in clinical trials. Although there was no difference between MMT scores from ARM affected eyes and controls, the MMT has the advantage over the Amsler grid in that it uses a letter target, has a peripheral fixation aid, and it provides a numerical score. This score could be beneficial in office and home monitoring of AMD progression, as well as an outcome measure in clinical research.

  8. Test particle acceleration in torsional fan reconnection

    Science.gov (United States)

    Hosseinpour, M.

    2014-12-01

    Magnetic reconnection is understood to be a potential mechanism for particle acceleration in astrophysical and space plasmas, especially in solar flares. Torsional fan reconnection is one of the proposed mechanisms for steady-state three-dimensional (3D) magnetic reconnection. By using the magnetic and electric fields for `torsional fan reconnection', the features of test particle acceleration with input parameters for the solar corona are investigated numerically. We show that torsional fan reconnection is potentially an efficient particle accelerator and a proton can gain up to tens of MeV of kinetic energy within only a few milliseconds. Although the final kinetic energy of the accelerated particle depends on the injection position but there exists only one scenario for the particle's trajectory with different initial positions in which the particle is accelerated on the fan plane. Moreover, adopting either spatially uniform or non-uniform localized plasma resistivity does not much influence the features of trajectory. These results are compared with those of torsional spine reconnection.

  9. Step-Stress Accelerated Degradation Testing for Solar Reflectors: Preprint

    Energy Technology Data Exchange (ETDEWEB)

    Jones, W.; Elmore, R.; Lee, J.; Kennedy, C.

    2011-09-01

    To meet the challenge to reduce the cost of electricity generated with concentrating solar power (CSP) new low-cost reflector materials are being developed including metalized polymer reflectors and must be tested and validated against appropriate failure mechanisms. We explore the application of testing methods and statistical inference techniques for quantifying estimates and improving lifetimes of concentrating solar power (CSP) reflectors associated with failure mechanisms initiated by exposure to the ultraviolet (UV) part of the solar spectrum. In general, a suite of durability and reliability tests are available for testing a variety of failure mechanisms where the results of a set are required to understand overall lifetime of a CSP reflector. We will focus on the use of the Ultra-Accelerated Weathering System (UAWS) as a testing device for assessing various degradation patterns attributable to accelerated UV exposure. Depending on number of samples, test conditions, degradation and failure patterns, test results may be used to derive insight into failure mechanisms, associated physical parameters, lifetimes and uncertainties. In the most complicated case warranting advanced planning and statistical inference, step-stress accelerated degradation (SSADT) methods may be applied.

  10. Accelerated stress testing of thin film solar cells: Development of test methods and preliminary results

    Science.gov (United States)

    Lathrop, J. W.

    1985-01-01

    If thin film cells are to be considered a viable option for terrestrial power generation their reliability attributes will need to be explored and confidence in their stability obtained through accelerated testing. Development of a thin film accelerated test program will be more difficult than was the case for crystalline cells because of the monolithic construction nature of the cells. Specially constructed test samples will need to be fabricated, requiring committment to the concept of accelerated testing by the manufacturers. A new test schedule appropriate to thin film cells will need to be developed which will be different from that used in connection with crystalline cells. Preliminary work has been started to seek thin film schedule variations to two of the simplest tests: unbiased temperature and unbiased temperature humidity. Still to be examined are tests which involve the passage of current during temperature and/or humidity stress, either by biasing in the forward (or reverse) directions or by the application of light during stress. Investigation of these current (voltage) accelerated tests will involve development of methods of reliably contacting the thin conductive films during stress.

  11. Vacuum system for Advanced Test Accelerator

    Energy Technology Data Exchange (ETDEWEB)

    Denhoy, B.S.

    1981-09-03

    The Advanced Test Accelerator (ATA) is a pulsed linear electron beam accelerator designed to study charged particle beam propagation. ATA is designed to produce a 10,000 amp 50 MeV, 70 ns electron beam. The electron beam acceleration is accomplished in ferrite loaded cells. Each cell is capable of maintaining a 70 ns 250 kV voltage pulse across a 1 inch gap. The electron beam is contained in a 5 inch diameter, 300 foot long tube. Cryopumps turbomolecular pumps, and mechanical pumps are used to maintain a base pressure of 2 x 10/sup -6/ torr in the beam tube. The accelerator will be installed in an underground tunnel. Due to the radiation environment in the tunnel, the controlling and monitoring of the vacuum equipment, pressures and temperatures will be done from the control room through a computer interface. This paper describes the vacuum system design, the type of vacuum pumps specified, the reasons behind the selection of the pumps and the techniques used for computer interfacing.

  12. Investigation of reliability attributes and accelerated stress factors on terrestrial solar cells. Third annual report

    Energy Technology Data Exchange (ETDEWEB)

    Lathrop, J.W.; Hartman, R.A.; Saylor, C.R.

    1981-01-01

    The third year of the accelerated reliability testing program concentrated on electrical measurement instrumentation and in modeling cell behavior in the second quadrant. In addition, some preliminary work was done on correlating cell color changes with electrical degradation. Not reported are results of continuing accelerated stress tests on state of the art cells. A number of new cells were added to the program, but not in time for sufficient data to be obtained, while the older cells are undergoing extended test periods and new data are not yet available on them. The all-digital, microprocessor controlled, short interval tester, which was designed and fabricated, has replaced the manual measurement procedure formerly used. This has improved measurement accuracy and repeatability, reduced measurement time, and through coordinated data management procedures, eliminated data errors. A complete description of the tester including schematics and software is given and its operating procedures described. A computer model, based on the thermal and electrical properties of the cells and encapsulating materials, was developed to relate cell temperature to electrical characteristics in the second quadrant. This model adequately predicted the behavior of both encapsulated and unencapsulated cells, although accurate temperature measurements on encapsulated cells were difficult to obtain. In addition, only cells of one type were used for comparison and other cell types may require different parameter values for fitting. Use of the model should permit the prediction of a cell's sensitivity to degradation in the second quadrant. The computer program is listed together with a description of its operation.

  13. Ultra-accelerated natural sunlight exposure testing

    Energy Technology Data Exchange (ETDEWEB)

    Jorgensen, G.J.; Bingham, C.; Goggin, R.; Lewandowski, A.A.; Netter, J.C.

    2000-06-13

    Process and apparatus are disclosed for providing ultra accelerated natural sunlight exposure testing of samples under controlled weathering without introducing unrealistic failure mechanisms in exposed materials and without breaking reciprocity relationships between flux exposure levels and cumulative dose that includes multiple concurrent levels of temperature and relative humidity at high levels of natural sunlight comprising: (a) concentrating solar flux uniformly; (b) directing the controlled uniform sunlight onto sample materials in a chamber enclosing multiple concurrent levels of temperature and relative humidity to allow the sample materials to be subjected to accelerated irradiance exposure factors for a sufficient period of time in days to provide a corresponding time of about at least a years worth of representative weathering of the sample materials.

  14. Ultra-accelerated natural sunlight exposure testing

    Energy Technology Data Exchange (ETDEWEB)

    Jorgensen, Gary J. (Pine, CO); Bingham, Carl (Lakewood, CO); Goggin, Rita (Englewood, CO); Lewandowski, Allan A. (Evergreen, CO); Netter, Judy C. (Westminster, CO)

    2000-06-13

    Process and apparatus for providing ultra accelerated natural sunlight exposure testing of samples under controlled weathering without introducing unrealistic failure mechanisms in exposed materials and without breaking reciprocity relationships between flux exposure levels and cumulative dose that includes multiple concurrent levels of temperature and relative humidity at high levels of natural sunlight comprising: a) concentrating solar flux uniformly; b) directing the controlled uniform sunlight onto sample materials in a chamber enclosing multiple concurrent levels of temperature and relative humidity to allow the sample materials to be subjected to accelerated irradiance exposure factors for a sufficient period of time in days to provide a corresponding time of about at least a years worth of representative weathering of the sample materials.

  15. Reliability Analysis on English Writing Test of SHSEE in Shanghai

    Institute of Scientific and Technical Information of China (English)

    黄玉麒; 黄芳

    2014-01-01

    As a subjective test, the validity of writing test is acceptable. What about the reliability? Writing test occupies a special position in the senior high school entrance examination (SHSEE for short). It is important to ensure its reliability. By the analysis of recent years’English writing items in SHSEE, the author offer suggestions on how to guarantee the reliability of writing tests.

  16. Accelerated leach test of paraffin waste forms

    Energy Technology Data Exchange (ETDEWEB)

    Choi, Heui Joo; Kim, Ju Youl; Cho, Young Ok; Park, Joo Wan [Nuclear Environment Technology Institute, KEPCO, Taejon (Korea, Republic of)

    1999-07-01

    Leach test for the paraffin waste forms, which was recently introduced to immobilize the dry radioactive waste concentrates at the nuclear power plants in Korea, was conducted in accordance with the Accelerated Leach Test adopted by ASTM as Standard Test Method. The specimens were made of 22 w% paraffin, 78 w% boric acid, and little amount of Co, Sr. and Cs to determine the leaching mechanism. Leach tests for the specimens with different amounts of additives were conducted at three temperatures to investigate the effect of additives on the leach rates. The leach rates of boric acid, Co, Sr, and Cs were measured. The results showed that boric acid and Co leached congruently. The leaching rates are dependent on the temperature as expected. The ALT computer program was used to simulate the experimental data. The ALT program calculation shows that the diffusion can not explain the experimental data. (author)

  17. Acquisition of reliable vacuum hardware for large accelerator systems

    Energy Technology Data Exchange (ETDEWEB)

    Welch, K.M.

    1995-09-06

    Credible and effective communications prove to be the major challenge in the acquisition of reliable vacuum hardware. Technical competence is necessary but not sufficient. The authors must effectively communicate with management, sponsoring agencies, project organizations, service groups, staff and with vendors. Most of Deming`s 14 quality assurance tenants relate to creating an enlightened environment of good communications. All projects progress along six distinct, closely coupled, dynamic phases. All six phases are in a state of perpetual change. These phases and their elements are discussed, with emphasis given to the acquisition phase and its related vocabulary. Large projects require great clarity and rigor as poor communications can be costly. For rigor to be cost effective, it can`t be pedantic. Clarity thrives best in a low-risk, team environment.

  18. Validity and reliability of intra-stroke kayak velocity and acceleration using a GPS-based accelerometer.

    Science.gov (United States)

    Janssen, Ina; Sachlikidis, Alexi

    2010-03-01

    The aim of this study was to assess the validity and reliability of the velocity and acceleration measured by a kayak-mounted GPS-based accelerometer units compared to the video-derived measurements and the effect of satellite configuration on velocity. Four GPS-based accelerometers units of varied accelerometer ranges (2 g or 6 g) were mounted on a kayak as the paddler performed 12 trials at three different stroke rates for each of three different testing sessions (two in the morning vs. one in the afternoon). The velocity and acceleration derived by the accelerometers was compared with the velocity and acceleration derived from high-speed video footage (100Hz). Validity was measured using Bland and Altman plots, R2, and the root of the mean of the squared difference (RMSe), while reliability was calculated using the coefficient of variation, R2, and repeated measures analysis of variance (ANOVA) tests. The GPS-based accelerometers under-reported kayak velocity by 0.14-0.19 m/s and acceleration by 1.67 m/s2 when compared to the video-derived measurements. The afternoon session reported the least difference, indicating a time of day effect on the velocity measured. This study highlights the need for sports utilising GPS-based accelerometers, such as minimaxX, for intra-stroke measurements to conduct sport-specific validity and reliability studies to ensure the accuracy of their data.

  19. Software Reliability, Measurement, and Testing. Volume 2. Guidebook for Software Reliability Measurement and Testing

    Science.gov (United States)

    1992-04-01

    test experiments. Of the three static techniques, 200-4 SOFTWARE TEST TECHNIQUES ST Code Review A Error/ Anamoly Detection T I Structure...anomaly is an unforeseen event , which may not be detected by error-protection mechanisms in time to prevent system failure. The existence of extensive... event , the more difficult it is to make a meaningful prediction. As an example, it can be seen that the reliability of an electronic equipment is known

  20. Analysis on testing and operational reliability of software

    Institute of Scientific and Technical Information of China (English)

    ZHAO Jing; LIU Hong-wei; CUI Gang; WANG Hui-qiang

    2008-01-01

    Software reliability was estimated based on NHPP software reliability growth models. Testing reliability and operational reliability may be essentially different. On the basis of analyzing similarities and differences of the testing phase and the operational phase, using the concept of operational reliability and the testing reliability, different forms of the comparison between the operational failure ratio and the predicted testing failure ratio were conducted, and the mathematical discussion and analysis were performed in detail. Finally, software optimal release was studied using software failure data. The results show that two kinds of conclusions can be derived by applying this method, one conclusion is to continue testing to meet the required reliability level of users, and the other is that testing stops when the required operational reliability is met, thus the testing cost can be reduced.

  1. Test particle acceleration in explosive magnetohydrodynamic reconnection

    CERN Document Server

    Ripperda, Bart; Xia, Chun; Keppens, Rony

    2016-01-01

    Magnetic reconnection is the mechanism behind many violent phenomena in the universe. We demonstrate that energy released during reconnection can lead to non-thermal particle distribution functions. We use a method in which we combine resistive magnetohydrodynamics (MHD) with relativistic test particle dynamics. Using our open-source grid-adaptive MPI-AMRVAC software, we simulate global MHD evolution combined with test particle treatments in MHD snapshots. This approach is used to evaluate particle acceleration in explosive reconnection. The reconnection is triggered by an ideal tilt instability in two-and-a-half dimensional (2.5D) scenarios and by a combination of ideal tilt and kink instabilities in three-dimensional (3D) scenarios. These instabilities occur in a system with two parallel, adjacent, repelling current channels in an initially force-free equilibrium, as a simplified representation of flux ropes in a stellar magnetosphere. The current channels undergo a rotation and a separation on Alfv\\'enic t...

  2. Test-retest reliability for hitting accuracy tennis test.

    Science.gov (United States)

    Strecker, Estevam; Foster, Ernest B; Pascoe, David D

    2011-12-01

    Strecker, E, Foster, EB, and Pascoe, DD. Test-retest reliability for hitting accuracy tennis test. J Strength Cond Res 25(12): 3501-3505, 2011-The purpose of this investigation was to assess a test-retest reliability of the hitting accuracy tennis test (HATT). Twelve National Collegiate Athletic Association (NCAA) division I tennis players (4 men and 8 women) volunteered to participate in this investigation. Skill tests consisted of 15 consecutive ground strokes in all 4 directions (forehand [FH] and backhand [BH]; crosscourt and up the line) with not >1 minute between directions. The court was divided into 12 areas, and each area was assigned a value according to a grid system based on offensive, defensive, and neutral shots ranging from 1 point to 6 points. Total score, unforced errors, and shot index (total number of shots that landed on optimal performance areas 5 and 6 minus total number of unforced errors) were used for statistical analysis. The order of shot direction was randomized between participants and trials. The analysis of variance with repeated measures (p value ≤ 0.05) of this investigation showed no statistical difference between trials on any of the measurements. The results also suggest that division I level tennis players have the ability to hit accurately specific targets on a tennis court using either FH or BH with minimal daily variation. Therefore, we conclude that the HATT for trained tennis athletes is a simple, reliable, and accurate assessment tool to measure tennis skill performance based on accuracy. The HATT is also an easy, inexpensive training device that coaches can use to monitor players development.

  3. First Assessment of Reliability Data for the LHC Accelerator and Detector Cryogenic System Components

    CERN Document Server

    Perinic, G; Alonso-Canella, I; Balle, C; Barth, K; Bel, J F; Benda, V; Bremer, J; Brodzinski, K; Casas-Cubillos, J; Cuccuru, G; Cugnet, M; Delikaris, D; Delruelle, N; Dufay-Chanat, L; Fabre, C; Ferlin, G; Fluder, C; Gavard, E; Girardot, R; Haug, F; Herblin, L; Junker, S; Klabi , T; Knoops, S; Lamboy, J P; Legrand, D; Metselaar, J; Park, A; Perin, A; Pezzetti, M; Penacoba-Fernandez, G; Pirotte, O; Rogez, E; Suraci, A; Stewart, L; Tavian, L J; Tovar-Gonzalez, A; Van Weelderen, R; Vauthier, N; Vullierme, B; Wagner, U

    2012-01-01

    The Large Hadron Collider (LHC) cryogenic system comprises eight independent refrigeration and distribution systems that supply the eight 3.3 km long accelerator sectors with cryogenic refrigeration power as well as four refrigeration systems for the needs of the detectors ATLAS and CMS. In order to ensure the highest possible reliability of the installations, it is important to apply a reliability centred approach for the maintenance. Even though large scale cryogenic refrigeration exists since the mid 20th century, very little third party reliability data is available today. CERN has started to collect data with its computer aided maintenance management system (CAMMS) in 2009, when the accelerator has gone into normal operation. This paper presents the reliability observations from the operation and the maintenance side, as well as statistical data collected by the means of the CAMMS system.

  4. Stripline kicker for integrable optics test accelerator

    Energy Technology Data Exchange (ETDEWEB)

    Antipov, Sergey A.; Didenko, Alexander; Lebedev, Valeri; Valishev, Alexander

    2016-06-30

    We present a design of a stripline kicker for Integrable Optics Test Accelerator (IOTA). For its experimental program IOTA needs two full-aperture kickers, capable to create an arbitrary controllable kick in 2D. For that reason their strengths are variable in a wide range of amplitudes up to 16 mrad, and the pulse length 100 ns is less than a revolution period for electrons. In addition, the kicker should have a physical aperture of 40 mm for a proposed operation with proton beam, and an outer size of 70 mm to fit inside existing quadrupole magnets to save space in the ring. Computer simulations using CST Microwave Studio show high field uniformity and wave impedance close to 50 {\\Omega}.

  5. Stripline kicker for integrable optics test accelerator

    CERN Document Server

    Antipov, Sergey A; Lebedev, Valeri; Valishev, Alexander

    2016-01-01

    We present a design of a stripline kicker for Integrable Optics Test Accelerator (IOTA). For its experimental program IOTA needs two full-aperture kickers, capable to create an arbitrary controllable kick in 2D. For that reason their strengths are variable in a wide range of amplitudes up to 16 mrad, and the pulse length 100 ns is less than a revolution period for electrons. In addition, the kicker should have a physical aperture of 40 mm for a proposed operation with proton beam, and an outer size of 70 mm to fit inside existing quadrupole magnets to save space in the ring. Computer simulations using CST Microwave Studio show high field uniformity and wave impedance close to 50 {\\Omega}.

  6. Planck Scale Gravity Test with Accelerators

    Science.gov (United States)

    Gharibyan, V.

    2015-01-01

    Quantum or torsion gravity models predict unusual properties of space-time at very short distances. In particular, near the Planck length, around 10-35m, empty space may behave as a crystal, singly or doubly refractive. However, this hypothesis remains uncheckable for any direct measurement since the smallest distance accessible in experiment is about 10-19m at the LHC. Here I propose a laboratory test to measure the space refractivity and birefringence induced by gravity. A sensitivity from 10-31m down to the Planck length could be reached at existent GeV and future TeV energy lepton accelerators using laser Compton scattering. There are already experimental hints for gravity signature at distances approaching the Planck length by 5-7 orders of magnitude, derived from SLC and HERA data.

  7. Testing Planck-Scale Gravity with Accelerators

    Science.gov (United States)

    Gharibyan, Vahagn

    2012-10-01

    Quantum or torsion gravity models predict unusual properties of space-time at very short distances. In particular, near the Planck length, around 10-35m, empty space may behave as a crystal, singly or doubly refractive. However, this hypothesis remains uncheckable for any direct measurement, since the smallest distance accessible in experiment is about 10-19m at the LHC. Here I propose a laboratory test to measure the space refractivity and birefringence induced by gravity. A sensitivity from 10-31m down to the Planck length could be reached at existent GeV and future TeV energy lepton accelerators using laser Compton scattering. There are already experimental hints for gravity signature at distances approaching the Planck length by 5-7 orders of magnitude, derived from SLC and HERA data.

  8. Reliability Compliance Testing of Electronic Components for Consumer Electronics

    OpenAIRE

    Peciakowski, E.; Przybyl, E.

    1985-01-01

    In this paper the organisation of reliability compliance testing of electronic components in Poland is discussed. The aim of the testing is to find the reliability of the components to both producer and user and hence to establish reliability for the two parties. The system described is derived from standard methods and has two aims. These are:-1) To enable periodical checks of production to be made.2) To estimate the reliability level of the components produced.Sampling plans are constructed...

  9. Conceptualizing Essay Tests' Reliability and Validity: From Research to Theory

    Science.gov (United States)

    Badjadi, Nour El Imane

    2013-01-01

    The current paper on writing assessment surveys the literature on the reliability and validity of essay tests. The paper aims to examine the two concepts in relationship with essay testing as well as to provide a snapshot of the current understandings of the reliability and validity of essay tests as drawn in recent research studies. Bearing in…

  10. Two Aspects of Scorer Reliability in the Bender Gestalt Test

    Science.gov (United States)

    Morsbach, Gisela; And Others

    1975-01-01

    This study investigated (a) interscorer reliability of the Bender-Gestalt Test by using more than one person to score the same test protocols; and (b) rate-rerate reliability of the Bender-Gestalt Test after a half-year interval. (Author)

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

    Science.gov (United States)

    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…

  12. The Advanced Test Accelerator (ATA) experience

    Energy Technology Data Exchange (ETDEWEB)

    Chambers, F.W.

    1990-10-01

    On January 26, 1990 at 20:03:30, the Advanced Test Accelerator (ATA) was turned off with the shot counter reading 12,425,999. During the interval between 1985 and 1990 there were eight major experiments performed at ATA. Three of these experiments were for the Free Electron Laser program, and five were for the Charged Particle Beam (CPB) program. The five experiments were: Spring 1985 Propagation Experiment (April 1985), December 1985 20m Propagation Experiment (December 1985), Open Air Experiment (March--June 1987), Beam Transport Experiment (Spring 1988), and Multi Pulse Propagation Experiment (September 89--January 90). Several new technologies such as the rise time sharpener, the Beam Director, and the Fast Corrector Coil were also developed. Experiments for diagnostic development such as the transition radiation studies were also conducted. In this report the major experiments will be revisited; their highlights and shortcomings will be outlined. The current view on the understanding of lead pulse stability and CPB feasibility will be discussed.

  13. Design stage confirmation of lifetime improvement for newly modified products through accelerated life testing

    Energy Technology Data Exchange (ETDEWEB)

    Mohammadian, S. Hossein, E-mail: seyed-h.mohammadian.1@ulaval.c [Centre Interuniversitaire de Recherche sur les Reseaux d' Entreprise, la Logistique et le Transport (CIRRELT), Departement de Genie Mecanique, Pavillon Adrien-Pouliot, Universite Laval, Quebec, G1V 0A6 (Canada) and Centre Interdisciplinaire de Recherche en Readaptation et en Integration Sociale (CIRRIS), Institut de Readaptation en Deficience Physique de Quebec, 525 Boul. Hamel, Quebec, G1M 2S8 (Canada); Ait-Kadi, Daoud, E-mail: Daoud.Aitkadi@gmc.ulaval.c [Centre Interuniversitaire de Recherche sur les Reseaux d' Entreprise, la Logistique et le Transport (CIRRELT), Departement de Genie Mecanique, Pavillon Adrien-Pouliot, Universite Laval, Quebec, G1V 0A6 (Canada); Centre Interdisciplinaire de Recherche en Readaptation et en Integration Sociale (CIRRIS), Institut de Readaptation en Deficience Physique de Quebec, 525 Boul. Hamel, Quebec, G1M 2S8 (Canada)

    2010-08-15

    After a modification to the original version of a product and before mass production, the expected improvement in the product lifetime or reliability needs to be validated. This paper presents three approaches based on accelerated life testing to verify, estimate and confirm the lifetime or reliability of a newly modified product at design stage: ALT comparative approach, reliability estimation approach, and reliability validation test. Test samples of the original and modified versions are expected to fail during the tests in order to obtain their failure time data. In ALT comparative approach, the statistical comparison between failure time data of the original and modified versions is used to verify the required improvement in lifetime. In reliability estimation approach, the relationship made between available lifetime and failure time data of the original version is used to extrapolate lifetime data of the modified version from its failure time data. Since modified versions are usually highly reliable, all test samples might survive the tests (without any failures) that results in the lack of failure time data for statistical analysis. To confirm a level of service reliability with confidence, reliability validation test is presented to make an estimate of the number of samples required to survive the tests. To fulfill the same level of confidence for fewer number of prototypes (as test samples), the test time must be extended. On the other hand, more prototypes are needed to pass a shorter test time if there are any time constraints.

  14. A wireless accelerometer node for reliable and valid measurement of lumbar accelerations during treadmill running.

    Science.gov (United States)

    Lindsay, Timothy R; Yaggie, James A; McGregor, Stephen J

    2016-01-01

    This study investigated the reliability of a wireless accelerometer and its agreement with optical motion capture for the measurement of root mean square (RMS) acceleration during running. RMS acceleration provides a whole-body metric of movement mechanics and economy. Fifteen healthy college-age participants performed treadmill running for two 60-s trials at 2.22, 2.78, and 3.33 m/s and one trial of 150 s (five 30-s epochs) at 2.78 m/s. We assessed between-trial and within-trial reliability, and agreement in each axis between a trunk-mounted wireless accelerometer and a reflective marker on the accelerometer measured by optical motion capture. Intraclass correlations assessing between-trial repeatability were 0.89-0.97, depending on the axis, and intraclass correlations assessing within-trial repeatability were 0.99-1.00. Bland-Altman analyses assessing agreement indicated mean difference values between -0.03 and 0.03 g, depending on the axis. Anterio-posterior acceleration had the greatest limits of agreement (LOA) (±0.12 g) and vertical acceleration had the smallest LOA (±0.03 g). For measuring RMS acceleration of the trunk, this wireless accelerometer node provides repeatable and valid measurement compared with the standard laboratory method of optical motion capture.

  15. Sequential accelerated tests: Improving the correlation of accelerated tests to module performance in the field

    Science.gov (United States)

    Felder, Thomas; Gambogi, William; Stika, Katherine; Yu, Bao-Ling; Bradley, Alex; Hu, Hongjie; Garreau-Iles, Lucie; Trout, T. John

    2016-09-01

    DuPont has been working steadily to develop accelerated backsheet tests that correlate with solar panels observations in the field. This report updates efforts in sequential testing. Single exposure tests are more commonly used and can be completed more quickly, and certain tests provide helpful predictions of certain backsheet failure modes. DuPont recommendations for single exposure tests are based on 25-year exposure levels for UV and humidity/temperature, and form a good basis for sequential test development. We recommend a sequential exposure of damp heat followed by UV then repetitions of thermal cycling and UVA. This sequence preserves 25-year exposure levels for humidity/temperature and UV, and correlates well with a large body of field observations. Measurements can be taken at intervals in the test, although the full test runs 10 months. A second, shorter sequential test based on damp heat and thermal cycling tests mechanical durability and correlates with loss of mechanical properties seen in the field. Ongoing work is directed toward shorter sequential tests that preserve good correlation to field data.

  16. Reliability of 16 balance tests in individuals with Down syndrome.

    Science.gov (United States)

    Villamonte, Romina; Vehrs, Pat R; Feland, J Brent; Johnson, A Wayne; Seeley, Matthew K; Eggett, Dennis

    2010-10-01

    To assess test-retest reliability scores on 16 balance tests of 21 individuals with Down syndrome whose ages ranged from 5 to 31 yr., participants performed a standing test on firm and soft surfaces with the eyes open and closed, the balance subset of the Bruininks-Oseretsky test, full turn, timed-up-and-go test, forward reach, and sit-to-stand. Each participant completed all 16 tests twice in one day and then again on a subsequent day for a total of 4 sessions. The interclass reliability correlation coefficients (ICC) value for each measure of balance varied considerably by age and sex. Based on having an ICC > .50, only 3 tests were reliable in young males and young females, whereas 5 tests could reliably be used in adult females and 9 tests could reliably be used in adult males. The results of this study raise suspicions as to the reliability of tests commonly used to assess balance and differences in reliability due to age and sex. Results of balance tests should be interpreted with caution in males and females with Down syndrome across the age span.

  17. Accelerated lifetime testing of energy storage capacitors used in particle accelerators power converters

    CERN Document Server

    AUTHOR|(SzGeCERN)679542; Genton, Charles-Mathieu

    2015-01-01

    Energy storage capacitors are used in large quantities in high power converters for particle accelerators. In this application capacitors see neither a DC nor an AC voltage but a combination of the two. The paper presents a new power converter explicitly designed to perform accelerated testing on these capacitors and the results of the tests.

  18. Renyi Criterion Modification in Testing the Hypotheses About Acceleration Factor Meaning at Variable-Load Tests

    Directory of Open Access Journals (Sweden)

    N. D. Tiannikova

    2014-01-01

    Full Text Available This paper concerns the acceleration factor estimation at strenuous tests of products in case of unstable production process (different batches of the same products may be with different index of reliability.Kartashov has developed techniques for determining the invariant functional from batch to batch, which convert accelerated test results to the normal mode. Its highlight is to conduct socalled preliminary tests of one sample of products, including pre-tests in the variable mode. The standard procedure for the preliminary tests (examination is as follows: testing the n groups of products, with m elements in each group, begins in the normal mode. As soon as one of the products in the group fails, tests of remaining products start in the accelerated mode. In addition to tests in the variable mode, there are also tests conducted in the constantly normal mode. As a result of such tests of products from one batch, an acceleration factor of strenuous tests is determined for this type of products for any batch.The described procedure has the following shortcomings:• tests duration in the normal mode is long and, as a result, is very much time-consuming and cost-demandable;• tests conducted in the variable mode to the failure of all the products have the same drawback.This paper proposes a method for conducting the preliminary studies. It does not require testing in the constant mode and, additionally, allows tests duration in the variable mode to be restricted by the moment of the first failure in the r group. To analyze the results of such tests the Renyi type criterion of homogeneity of two samples is suggested. A method for calculating the distribution of its statistics for the finite sample sizes is developed and implemented in the software complex. The asymptotic distribution of the statistics is given. The estimate of the acceleration factor is provided by its minimization. It is shown that for real sample sizes of products only exact

  19. AREAL test facility for advanced accelerator and radiation source concepts

    Energy Technology Data Exchange (ETDEWEB)

    Tsakanov, V.M., E-mail: tsakanov@asls.candle.am [CANDLE Synchrotron Research Institute, 0040 Yerevan (Armenia); Amatuni, G.A.; Amirkhanyan, Z.G.; Aslyan, L.V.; Avagyan, V.Sh.; Danielyan, V.A.; Davtyan, H.D.; Dekhtiarov, V.S.; Gevorgyan, K.L.; Ghazaryan, N.G.; Grigoryan, B.A.; Grigoryan, A.H.; Hakobyan, L.S. [CANDLE Synchrotron Research Institute, 0040 Yerevan (Armenia); Haroutiunian, S.G. [Yerevan State University, 0025 Yerevan (Armenia); Ivanyan, M.I.; Khachatryan, V.G.; Laziev, E.M. [CANDLE Synchrotron Research Institute, 0040 Yerevan (Armenia); Manukyan, P.S. [State Engineering University of Armenia, 0009 Yerevan (Armenia); Margaryan, I.N.; Markosyan, T.M. [CANDLE Synchrotron Research Institute, 0040 Yerevan (Armenia); and others

    2016-09-01

    Advanced Research Electron Accelerator Laboratory (AREAL) is a 50 MeV electron linear accelerator project with a laser driven RF gun being constructed at the CANDLE Synchrotron Research Institute. In addition to applications in life and materials sciences, the project aims as a test facility for advanced accelerator and radiation source concepts. In this paper, the AREAL RF photoinjector performance, the facility design considerations and its highlights in the fields of free electron laser, the study of new high frequency accelerating structures, the beam microbunching and wakefield acceleration concepts are presented.

  20. Results of metallographical diagnostic examination of Navy half-watt thermoelectric converters degraded by accelerated tests

    Science.gov (United States)

    Rosell, F. E., Jr.; Rouklove, P. G.

    1977-01-01

    To verify the 15-year reliability of the Navy half-watt radioisotope thermoelectric generator (RTG), bismuth-telluride thermoelectric converters were submitted to testing at high temperatures which accelerated the degradation and caused failure of the converters. Metallographic diagnostic examination of failed units verified failure mechanisms. Results of diagnostic examinations are presented.

  1. Accelerated life testing effects on CMOS microcircuit characteristics

    Science.gov (United States)

    1980-01-01

    The 250 C, 200C and 125C accelerated tests are described. The wear-out distributions from the 250 and 200 C tests were used to estimate the activation energy between the two test temperatures. The duration of the 125 C test was not sufficient to bring the test devices into the wear-out region. It was estimated that, for the most complex of the three devices types, the activation energy between 200 C and 125 C should be at least as high as that between 250 C and 200 C. The practicality of the use of high temperature for the accelerated life tests from the point of view of durability of equipment is assessed. Guidlines for the development of accelerated life-test conditions are proposed. The use of the silicon nitride overcoat to improve the high temperature accelerated life-test characteristics of CMOS microcircuits is described.

  2. Acceptance sampling reliability test plans for alpha distributed lifetime

    OpenAIRE

    Khan, Maroof A.; Islam, H. M.

    2013-01-01

    Determining the acceptability of any product, reliability sampling plans are used. In this paper, reliability sampling plans for truncated life test are developed when the lifetimes of a test follow an alpha distribution. The sampling plan proposed here can save the test time in practical situations. Sampling plans are established through an algorithm. Moreover, some tables are provided for the proposed sampling plans so that proposed method can be used conveniently for the practitioner. Oper...

  3. Robust Design of Reliability Test Plans Using Degradation Measures.

    Energy Technology Data Exchange (ETDEWEB)

    Lane, Jonathan Wesley; Lane, Jonathan Wesley; Crowder, Stephen V.; Crowder, Stephen V.

    2014-10-01

    With short production development times, there is an increased need to demonstrate product reliability relatively quickly with minimal testing. In such cases there may be few if any observed failures. Thus, it may be difficult to assess reliability using the traditional reliability test plans that measure only time (or cycles) to failure. For many components, degradation measures will contain important information about performance and reliability. These measures can be used to design a minimal test plan, in terms of number of units placed on test and duration of the test, necessary to demonstrate a reliability goal. Generally, the assumption is made that the error associated with a degradation measure follows a known distribution, usually normal, although in practice cases may arise where that assumption is not valid. In this paper, we examine such degradation measures, both simulated and real, and present non-parametric methods to demonstrate reliability and to develop reliability test plans for the future production of components with this form of degradation.

  4. A Latent Class Approach to Estimating Test-Score Reliability

    Science.gov (United States)

    van der Ark, L. Andries; van der Palm, Daniel W.; Sijtsma, Klaas

    2011-01-01

    This study presents a general framework for single-administration reliability methods, such as Cronbach's alpha, Guttman's lambda-2, and method MS. This general framework was used to derive a new approach to estimating test-score reliability by means of the unrestricted latent class model. This new approach is the latent class reliability…

  5. IRT-Estimated Reliability for Tests Containing Mixed Item Formats

    Science.gov (United States)

    Shu, Lianghua; Schwarz, Richard D.

    2014-01-01

    As a global measure of precision, item response theory (IRT) estimated reliability is derived for four coefficients (Cronbach's a, Feldt-Raju, stratified a, and marginal reliability). Models with different underlying assumptions concerning test-part similarity are discussed. A detailed computational example is presented for the targeted…

  6. Application of a truncated normal failure distribution in reliability testing

    Science.gov (United States)

    Groves, C., Jr.

    1968-01-01

    Statistical truncated normal distribution function is applied as a time-to-failure distribution function in equipment reliability estimations. Age-dependent characteristics of the truncated function provide a basis for formulating a system of high-reliability testing that effectively merges statistical, engineering, and cost considerations.

  7. Reliability and Validity of the English Oral Test

    Institute of Scientific and Technical Information of China (English)

    王芳

    2009-01-01

    English oral test aims to provide a fair and valid measure of a testee's oral proficiency SO as to give an accurate description of his/her oral communicative ability.This paper analysesthe validity and reliability of the coHege enhance English oral test paper of Guangdong province of 2005.In designing an oral test,in order to make the test reliable,the teacher should take the following factors into consideration:test content,test method,testees' mood,rating scales and rater characteristics.

  8. Accelerators for Society - TIARA 2012 Test Infrastructure and Accelerator Research Area (in Polish)

    CERN Document Server

    Romaniuk, R S

    2013-01-01

    TIARA (Test Infrastructure and Accelerator Research Area - Preparatory Phae) is an European Collaboration of Accelerator Technology, which by running research projects, technical, networks and infrastructural has a duty to integrate the research and technical communities and infrastructures in the global scale of Europe. The Collaboration gathers all research centers with large accelerator infrastructures. Other ones, like universities, are affiliated as associate members. TIARA-PP (preparatory phase) is an European infrastructural project run by this Consortium and realized inside EU-FP7. The paper presents a general overview of TIARA activities, with an introduction containing a portrait of contemporary accelerator technology and a digest of its applications in modern society.

  9. Online cognition: factors facilitating reliable online neuropsychological test results.

    Science.gov (United States)

    Feenstra, Heleen E M; Vermeulen, Ivar E; Murre, Jaap M J; Schagen, Sanne B

    2017-01-01

    Online neuropsychological test batteries could allow for large-scale cognitive data collection in clinical studies. However, the few online neuropsychological test batteries that are currently available often still require supervision or lack proper psychometric evaluation. In this paper, we have outlined prerequisites for proper development and use of online neuropsychological tests, with the focus on reliable measurement of cognitive function in an unmonitored setting. First, we identified several technical, contextual, and psychological factors that should be taken into account in order to facilitate reliable test results of online tests in the unmonitored setting. Second, we outlined a methodology of quality assurance needed in order to obtain reliable cognitive data in the long run. Based on factors that distinguish the online unmonitored test setting from the traditional face-to-face setting, we provide a set of basic requirements and suggestions for optimal development and use of unmonitored online neuropsychological tests, including suggestions on acquiring reliability, validity, and norm scores. When properly addressing factors that could hamper reliable test results during development and use, online neuropsychological tests could aid large-scale data collection for clinical studies in the future. Investment in both proper development of online neuropsychological test platforms and the performance of accompanying psychometric studies is currently required.

  10. Molding compound trends in a denser packaging world: Qualification tests and reliability concerns

    Science.gov (United States)

    Nguyen, L. T.; Lo, R. H. Y.; Chen, A. S.; Belani, J. G.

    1993-12-01

    Molding compound development has traditionally been driven by the memory market, then subsequent applications filter down to other IC technologies such as logic, analog, and ASIC. However, this strategy has changed lately with the introduction of thin packages such as PQFP & TSOP. Rather than targeting a compound for a family of IC such as DRAM or SRAM, compound development efforts are now focused at specific classes of packages. The configurations of these thin packages impose new functional requirements that need to be revisited to provide the optimized combination of properties. The evolution of qualification tests mirrors the advances in epoxy and compounding technologies. From the first standard novolac-based epoxies of the 1970s to the latest 3(sup rd)-generation ultra-low stress materials, longer test times at increasingly harsher environments were achieved. This paper benchmarks the current reliability tests used by the electronic industry, examines those tests that affect and are affected by the molding compounds, discusses the relevance of accelerated testing, and addresses the major reliability issues facing current molding compound development efforts. Six compound-related reliability concerns were selected: moldability, package stresses, package cracking, halogen-induced intermetallic growth at bond pads, moisture-induced corrosion, and interfacial delamination. Causes of each failure type are surveyed and remedies are recommended. Accelerated tests are designed to apply to a limited quantity of devices, bias, or environmental conditions larger than usual ratings, to intensify failure mechanisms that would occur under normal operating conditions. The observed behavior is then extrapolated from the lot to the entire population. Emphasis is on compressing the time necessary to obtain reliability data. This approach has two main drawbacks. With increasingly complex devices, even accelerated tests are expensive. And with new technologies, it becomes

  11. Product acceptance environmental and destructive testing for reliability.

    Energy Technology Data Exchange (ETDEWEB)

    Dvorack, Michael A.; Kerschen, Thomas J.; Collins, Elmer W.

    2007-08-01

    To determine whether a component is meeting its reliability requirement during production, acceptance sampling is employed in which selected units coming off the production line are subjected to additional environmental and/or destructive tests that are within the normal environment space to which the component is expected to be exposed throughout its life in the Stockpile. This report describes what these tests are and how they are scored for reliability purposes. The roles of screens, Engineering Use Only tests, and next assembly product acceptance testing are also discussed, along with both the advantages and disadvantages of environmental and destructive testing.

  12. Long-Term Reliability of the Wonderlic Personnel Test.

    Science.gov (United States)

    Dodrill, Carl B.

    1983-01-01

    Compared the Wonderlic Personal Test and the Wechsler Adult Intelligence Scale for a sample of 30 adults first tested in 1976. The two tests were similar in reliability of clinical classification, but the Wonderlic demonstrated fewer practice effects. Despite its ease of administration, Wonderlic intelligence estimates appear stable. (Author/JAC)

  13. Long-Term Reliability of the Wonderlic Personnel Test.

    Science.gov (United States)

    Dodrill, Carl B.

    1983-01-01

    Compared the Wonderlic Personal Test and the Wechsler Adult Intelligence Scale for a sample of 30 adults first tested in 1976. The two tests were similar in reliability of clinical classification, but the Wonderlic demonstrated fewer practice effects. Despite its ease of administration, Wonderlic intelligence estimates appear stable. (Author/JAC)

  14. Estimating the Reliability of a Test Containing Multiple Item Formats.

    Science.gov (United States)

    Qualls, Audrey L.

    1995-01-01

    Classically parallel, tau-equivalently parallel, and congenerically parallel models representing various degrees of part-test parallelism and their appropriateness for tests composed of multiple item formats are discussed. An appropriate reliability estimate for a test with multiple item formats is presented and illustrated. (SLD)

  15. Reliability of four experimental mechanical pain tests in children

    Directory of Open Access Journals (Sweden)

    Soee AL

    2013-02-01

    Full Text Available Ann-Britt L Soee,1 Lise L Thomsen,2 Birte Tornoe,1,3 Liselotte Skov11Department of Pediatrics, Children’s Headache Clinic, Copenhagen University Hospital Herlev, Copenhagen, Denmark; 2Department of Neuropediatrics, Juliane Marie Centre, Copenhagen University Hospital Rigshospitalet, København Ø, Denmark; 3Department of Physiotherapy, Medical Department O, Copenhagen University Hospital Herlev, Herlev, DenmarkPurpose: In order to study pain in children, it is necessary to determine whether pain measurement tools used in adults are reliable measurements in children. The aim of this study was to explore the intrasession reliability of pressure pain thresholds (PPT in healthy children. Furthermore, the aim was also to study the intersession reliability of the following four tests: (1 Total Tenderness Score; (2 PPT; (3 Visual Analog Scale score at suprapressure pain threshold; and (4 area under the curve (stimulus–response functions for pressure versus pain.Participants and methods: Twenty-five healthy school children, 8–14 years of age, participated. Test 2, PPT, was repeated three times at 2 minute intervals on the same day to estimate PPT intrasession reliability using Cronbach’s alpha. Tests 1–4 were repeated after median 21 (interquartile range 10.5–22 days, and Pearson’s correlation coefficient was used to describe the intersession reliability.Results: The PPT test was precise and reliable (Cronbach’s alpha ≥ 0.92. All tests showed a good to excellent correlation between days (intersessions r = 0.66–0.81. There were no indications of significant systematic differences found in any of the four tests between days.Conclusion: All tests seemed to be reliable measurements in pain evaluation in healthy children aged 8–14 years. Given the small sample size, this conclusion needs to be confirmed in future studies.Keywords: repeatability, intraindividual reliability, pressure pain threshold, pain measurement, algometer

  16. Reliability of the Function in Sitting Test (FIST

    Directory of Open Access Journals (Sweden)

    Sharon L. Gorman

    2014-01-01

    Full Text Available The function in sitting test (FIST is a newly developed, performance-based measure examining deficits in seated postural control. The FIST has been shown to be internally consistent and valid in persons with neurological dysfunction but intra- and interrater reliability and test-retest reliability have not been previously described. Seven patients with chronic neurologic dysfunction were tested and videotaped performing the FIST on two consecutive days. Seventeen acute care and inpatient rehabilitation physical therapist raters scored six of the videotaped performance of the FIST on two occasions at least 2 weeks apart. Intraclass correlation coefficients were used to calculate the test-retest and intra- and interrater reliability of the FIST. ICC of 0.97 (95% CI 0.847–0.995 indicated excellent test-retest reliability of the FIST. Intra- and interrater reliability was also excellent with ICCs of 0.99 (95% CI 0.994–0.997 and 0.99 (95% CI 0.988–0.994, respectively. Physical therapists and other rehabilitation professionals can confidently use the FIST in a variety of clinical practice and research settings due to its favorable reliability characteristics. More studies are needed to describe the responsiveness and minimal clinically important level of change in FIST scores to further enhance clinical usefulness of this measure.

  17. Lunar RFC Reliability Testing for Assured Mission Success

    Science.gov (United States)

    Bents, David J.

    2008-01-01

    NASA's Constellation program has selected the closed cycle hydrogen oxygen Polymer Electrolyte Membrane (PEM) regenerative Fuel Cell (RFC) as its baseline solar energy storage system for the lunar outpost and manned rover vehicles. Since the outpost and manned rovers are "human-rated", these energy storage systems will have to be of proven reliability exceeding 99 percent over the length of the mission. Because of the low (TRL=5) development state of the closed cycle hydrogen oxygen PEM RFC at present, and because there is no equivalent technology base in the commercial sector from which to draw or infer reliability information from, NASA will have to spend significant resources developing this technology from TRL 5 to TRL 9, and will have to embark upon an ambitious reliability development program to make this technology ready for a manned mission. Because NASA would be the first user of this new technology, NASA will likely have to bear all the costs associated with its development. When well-known reliability estimation techniques are applied to the hydrogen oxygen RFC to determine the amount of testing that will be required to assure RFC unit reliability over life of the mission, the analysis indicates the reliability testing phase by itself will take at least 2 yr, and could take up to 6 yr depending on the number of QA units that are built and tested and the individual unit reliability that is desired. The cost and schedule impacts of reliability development need to be considered in NASA's Exploration Technology Development Program (ETDP) plans, since life cycle testing to build meaningful reliability data is the only way to assure "return to the moon, this time to stay, then on to Mars" mission success.

  18. Reliability of movement control tests in the lumbar spine

    Directory of Open Access Journals (Sweden)

    de Bruin Eling D

    2007-09-01

    Full Text Available Abstract Background Movement control dysfunction [MCD] reduces active control of movements. Patients with MCD might form an important subgroup among patients with non specific low back pain. The diagnosis is based on the observation of active movements. Although widely used clinically, only a few studies have been performed to determine the test reliability. The aim of this study was to determine the inter- and intra-observer reliability of movement control dysfunction tests of the lumbar spine. Methods We videoed patients performing a standardized test battery consisting of 10 active movement tests for motor control in 27 patients with non specific low back pain and 13 patients with other diagnoses but without back pain. Four physiotherapists independently rated test performances as correct or incorrect per observation, blinded to all other patient information and to each other. The study was conducted in a private physiotherapy outpatient practice in Reinach, Switzerland. Kappa coefficients, percentage agreements and confidence intervals for inter- and intra-rater results were calculated. Results The kappa values for inter-tester reliability ranged between 0.24 – 0.71. Six tests out of ten showed a substantial reliability [k > 0.6]. Intra-tester reliability was between 0.51 – 0.96, all tests but one showed substantial reliability [k > 0.6]. Conclusion Physiotherapists were able to reliably rate most of the tests in this series of motor control tasks as being performed correctly or not, by viewing films of patients with and without back pain performing the task.

  19. Reliability of four experimental mechanical pain tests in children

    DEFF Research Database (Denmark)

    Søe, Ann-Britt Langager; Thomsen, Lise L; Tornoe, Birte

    2013-01-01

    In order to study pain in children, it is necessary to determine whether pain measurement tools used in adults are reliable measurements in children. The aim of this study was to explore the intrasession reliability of pressure pain thresholds (PPT) in healthy children. Furthermore, the aim...... was also to study the intersession reliability of the following four tests: (1) Total Tenderness Score; (2) PPT; (3) Visual Analog Scale score at suprapressure pain threshold; and (4) area under the curve (stimulus-response functions for pressure versus pain)....

  20. A Reliability Test on PBGA Packaging Through Piezoresistive Stress Sensor

    OpenAIRE

    Liu, C.-H.; Chung, H.; Yang, D.-W.; Tseng, K.-F.; Lwo, B.-J.

    2009-01-01

    ISBN: 978-2-35500-009-6; Plastic packaging is the mainstream on microelectronic packaging technology at present. As the continuous requirements for smaller but higher density products, failure and reliability issues on MEMS/MOEMS packaging because of the hygroscopic swelling mismatch stress become more and more serious. To this end, this paper presented the stress monitoring methodologies as well as the reliability tests on a typical PBGA (Plastic Ball-Grid-Array) packaging due to hygroscopic...

  1. Reliability of a New Lower-Extremity Motor Coordination Test

    Directory of Open Access Journals (Sweden)

    Antosiak-Cyrak Katarzyna

    2015-12-01

    Full Text Available Introduction. Motor coordination is a basic motor ability necessary for daily life, which also allows athletes to win a sports rivalry and patients to assess their recovery progress after therapy and rehabilitation. The aim of the present study was to assess the reliability of a new lower-extremity rate of movements test and testing apparatus.

  2. Reliability and Validity of the Standing Heel-Rise Test

    Science.gov (United States)

    Yocum, Allison; McCoy, Sarah Westcott; Bjornson, Kristie F.; Mullens, Pamela; Burton, Gay Naganuma

    2010-01-01

    A standardized protocol for a pediatric heel-rise test was developed and reliability and validity are reported. Fifty-seven children developing typically (CDT) and 34 children with plantar flexion weakness performed three tests: unilateral heel rise, vertical jump, and force measurement using handheld dynamometry. Intraclass correlation…

  3. Test setup for long term reliability investigation of Silicon Carbide MOSFETs

    DEFF Research Database (Denmark)

    Baker, Nick; Munk-Nielsen, Stig; Beczkowski, Szymon

    2013-01-01

    Silicon Carbide MOSFETs are now widely available and have frequently been demonstrated to offer numerous advantages over Silicon based devices. However, reliability issues remain a significant concern in their realisation in commercial power electronic systems. In this paper, a test bench...... is designed that enables an accelerated power cycling test to be performed on packaged Silicon Carbide MOSFETs (TO-247) under realistic operating conditions. An accelerated power cycling test is then performed, with on-state resistance selected as the observed parameter to detect degradation. On......-state resistance is routinely monitored online through the use of an innovative voltage measurement system. The packaged Silicon Carbide MOSFET is shown to exhibit a 25% increase in on-state resistance as the device ages throughout its lifetime, with the test still on-going....

  4. Advanced test accelerator: a high-current induction linac

    Energy Technology Data Exchange (ETDEWEB)

    Cook, E.G.; Birx, D.L.; Reginato, L.L.

    1982-11-01

    The Advanced Test Accelerator (ATA) is a linear induction accelerator being built at Lawrence Livermore National Laboratory. The aim of the ATA, together with its associated physics program is the research and development necessary to resolve whether particle-beam propagation is possible. Since the accelerator is the tool needed to do the basic propagation experiment, many of its design parameters are specified by the physics. The accelerator parameters are: 50 MeV, 10 kA, 70 ns pulse width (FWHM), and a 1 kHz rep-rate during a ten-pulse burst. In addition, beam quality and pulse-to-pulse repeatability must be excellent. The unique features of the accelerator are the 10 kA beam and the 1 kHz burst frequency.

  5. Power test of the separated function RFQ accelerator

    Institute of Scientific and Technical Information of China (English)

    CHEN Jia-Er; ZHU Kun; GUO Zhi-Yu; LU Yuan-Rong; YAN Xue-Qing; GAO Shu-Li; WANG Zhi; KANG Ming-Lei; FANG Jia-Xun; YU Mao-Lin; LI Wei-Guo; GUO Ju-Fang

    2009-01-01

    The progress of the Separated Function RFQ(SFRFQ)accelerator,which can raise the field gradient of acceleration while maintaining the transverse focusing power sufficient for high current beam,is presented.In order to demonstrate the feasibilities of the novel accelerator,a prototype cavity was designed and constructed.Correspondingly,a code SFRFQCODEV 1.0 was developed specially for cavity design and beam dynamics simulation.The prototype cavity will be verified as a post-accelerator for ISR RFQ-1000 (Integral Split Ring RFQ)and accelerate O+ from 1 MeV to 1.6 MeV.To inject a higher current oxygen beam for the prototype cavity,the beam current of ISR RFQ-1000 was upgraded to 2 mA.The status of high power and beam test preparation for the prototype cavity are presented in this paper.

  6. Methodology to improve design of accelerated life tests in civil engineering projects.

    Directory of Open Access Journals (Sweden)

    Jing Lin

    Full Text Available For reliability testing an Energy Expansion Tree (EET and a companion Energy Function Model (EFM are proposed and described in this paper. Different from conventional approaches, the EET provides a more comprehensive and objective way to systematically identify external energy factors affecting reliability. The EFM introduces energy loss into a traditional Function Model to identify internal energy sources affecting reliability. The combination creates a sound way to enumerate the energies to which a system may be exposed during its lifetime. We input these energies into planning an accelerated life test, a Multi Environment Over Stress Test. The test objective is to discover weak links and interactions among the system and the energies to which it is exposed, and design them out. As an example, the methods are applied to the pipe in subsea pipeline. However, they can be widely used in other civil engineering industries as well. The proposed method is compared with current methods.

  7. Methodology to improve design of accelerated life tests in civil engineering projects.

    Science.gov (United States)

    Lin, Jing; Yuan, Yongbo; Zhou, Jilai; Gao, Jie

    2014-01-01

    For reliability testing an Energy Expansion Tree (EET) and a companion Energy Function Model (EFM) are proposed and described in this paper. Different from conventional approaches, the EET provides a more comprehensive and objective way to systematically identify external energy factors affecting reliability. The EFM introduces energy loss into a traditional Function Model to identify internal energy sources affecting reliability. The combination creates a sound way to enumerate the energies to which a system may be exposed during its lifetime. We input these energies into planning an accelerated life test, a Multi Environment Over Stress Test. The test objective is to discover weak links and interactions among the system and the energies to which it is exposed, and design them out. As an example, the methods are applied to the pipe in subsea pipeline. However, they can be widely used in other civil engineering industries as well. The proposed method is compared with current methods.

  8. Test-retest reliability of the Saladin card.

    Science.gov (United States)

    Corbett, Amanda; Maples, W C

    2004-10-01

    Test-retest reliability is a measure of the confidence that results will be identical when the same patient is measured with an instrument in the same manner on more than one occasion. Using the Saladin Near Point Balance Card--an instrument designed to test various near visual findings, including visual acuity, phorias, AC/A ratios, dynamic retinoscopy, fixation disparity, associated phorias, fixation disparity curves, as well as accommodative and vergence facilities--28 first- and second-year optometry students were evaluated on two occasions by one clinician, with the tests separated by approximately two weeks. Subjects were required to demonstrate 20/20 distance visual acuity and at least 100 sec of arc stereopsis. A total of 38 findings were compared, which included near horizontal and vertical phorias, associated phoria, and fixation disparity curves. Twenty-two findings were performed through the subjects' habitual prescription and the remaining findings were taken through the lens indicated by MEM retinoscopy. The purpose of this study was to investigate whether the Saladin Near Point Balance Card had acceptable test-retest reliability. If reliability can be demonstrated, this instrument could be used in clinical situations to diagnose visual departures from normal. All but two of the 38 tests performed demonstrated acceptable test-retest reliability. Coefficients of repeatability and 95% limits of agreement were calculated. The Saladin Near Point Balance Card demonstrated acceptable test-retest reliability. Since it is light-weight, portable, easily and quickly administered, and reliable, the Saladin card can be used by clinicians who are performing screenings or examinations in non-clinical situations, such as nursing homes or schools.

  9. Test-Retest Reliability of an Automated Infrared-Assisted Trunk Accelerometer-Based Gait Analysis System.

    Science.gov (United States)

    Hsu, Chia-Yu; Tsai, Yuh-Show; Yau, Cheng-Shiang; Shie, Hung-Hai; Wu, Chu-Ming

    2016-07-23

    The aim of this study was to determine the test-retest reliability of an automated infrared-assisted, trunk accelerometer-based gait analysis system for measuring gait parameters of healthy subjects in a hospital. Thirty-five participants (28 of them females; age range, 23-79 years) performed a 5-m walk twice using an accelerometer-based gait analysis system with infrared assist. Measurements of spatiotemporal gait parameters (walking speed, step length, and cadence) and trunk control (gait symmetry, gait regularity, acceleration root mean square (RMS), and acceleration root mean square ratio (RMSR)) were recorded in two separate walking tests conducted 1 week apart. Relative and absolute test-retest reliability was determined by calculating the intra-class correlation coefficient (ICC3,1) and smallest detectable difference (SDD), respectively. The test-retest reliability was excellent for walking speed (ICC = 0.87, 95% confidence interval = 0.74-0.93, SDD = 13.4%), step length (ICC = 0.81, 95% confidence interval = 0.63-0.91, SDD = 12.2%), cadence (ICC = 0.81, 95% confidence interval = 0.63-0.91, SDD = 10.8%), and trunk control (step and stride regularity in anterior-posterior direction, acceleration RMS and acceleration RMSR in medial-lateral direction, and acceleration RMS and stride regularity in vertical direction). An automated infrared-assisted, trunk accelerometer-based gait analysis system is a reliable tool for measuring gait parameters in the hospital environment.

  10. COMPACT PROTON INJECTOR AND FIRST ACCELERATOR SYSTEM TEST FOR COMPACT PROTON DIELECTRIC WALL CANCER THERAPY ACCELERATOR

    Energy Technology Data Exchange (ETDEWEB)

    Chen, Y; Guethlein, G; Caporaso, G; Sampayan, S; Blackfield, D; Cook, E; Falabella, S; Harris, J; Hawkins, S; Nelson, S; Poole, B; Richardson, R; Watson, J; Weir, J; Pearson, D

    2009-04-23

    A compact proton accelerator for cancer treatment is being developed by using the high-gradient dielectric insulator wall (DWA) technology [1-4]. We are testing all the essential DWA components, including a compact proton source, on the First Article System Test (FAST). The configuration and progress on the injector and FAST will be presented.

  11. Acceleration of the LHC commissioning tests

    CERN Multimedia

    2008-01-01

    The quadrupole and main dipole circuits have been powered up to 10,200 amps in Sector 4-5. Sector 5-6 is currently being cooled and will be the next to undergo electrical tests, which will be stepped up over the next few weeks.

  12. Analysis of lead-acid battery accelerated testing data

    Science.gov (United States)

    Clifford, J. E.; Thomas, R. E.

    1983-06-01

    Battelle conducted an independent review and analysis of the accelerated test procedures and test data obtained by Exide in the 3 year Phase 1 program to develop advanced lead acid batteries for utility load leveling. Of special importance is the extensive data obtained in deep discharge cycling tests on 60 cells at elevated temperatures over a 2-1/2 year period. The principal uncertainty in estimating cell life relates to projecting cycle life data at elevated temperature to the lower operating temperatures. The accelerated positive grid corrosion test involving continuous overcharge at 500C provided some indication of the degree of grid corrosion that might be tolerable before failure. The accelerated positive material shedding test was not examined in any detail. Recommendations are made for additional studies.

  13. The Advanced Superconducting Test Accelerator at Fermilab: Science Program

    Energy Technology Data Exchange (ETDEWEB)

    Piot, Philippe [Fermilab; Harms, Elvin [Fermilab; Henderson, Stuart [Fermilab; Leibfritz, Jerry [Fermilab; Nagaitsev, Sergei [Fermilab; Shiltsev, Vladimir [Fermilab; Valishev, Alexander [Fermilab

    2014-07-01

    The Advanced Superconducting Test Accelerator (ASTA) currently in commissioning phase at Fermilab is foreseen to support a broad range of beam-based experiments to study fundamental limitations to beam intensity and to develop novel approaches to particle-beam generation, acceleration and manipulation. ASTA incorporates a superconducting radiofrequency (SCRF) linac coupled to a flexible high-brightness photoinjector. The facility also includes a small-circumference storage ring capable of storing electrons or protons. This report summarizes the facility capabilities, and provide an overview of the accelerator-science researches to be enabled.

  14. Computer modeling of test particle acceleration at oblique shocks

    Science.gov (United States)

    Decker, Robert B.

    1988-01-01

    The present evaluation of the basic techniques and illustrative results of charged particle-modeling numerical codes suitable for particle acceleration at oblique, fast-mode collisionless shocks emphasizes the treatment of ions as test particles, calculating particle dynamics through numerical integration along exact phase-space orbits. Attention is given to the acceleration of particles at planar, infinitessimally thin shocks, as well as to plasma simulations in which low-energy ions are injected and accelerated at quasi-perpendicular shocks with internal structure.

  15. TERA high gradient test program of RF cavities for medical linear accelerators

    Energy Technology Data Exchange (ETDEWEB)

    Degiovanni, A., E-mail: alberto.degiovanni@cern.ch [TERA Foundation-via G. Puccini 11, 28100 Novara (Italy); Ecole Polytechnique Federale Lausanne EPFL-1015 Lausanne (Switzerland); Amaldi, U. [TERA Foundation-via G. Puccini 11, 28100 Novara (Italy); Universita Milano Bicocca-Piazza della Scienza 1, 20126 Milan (Italy); Bonomi, R. [TERA Foundation-via G. Puccini 11, 28100 Novara (Italy); Politecnico di Torino-Corso Duca degli Abruzzi 24, 10129 Turin (Italy); Garlasche, M. [TERA Foundation-via G. Puccini 11, 28100 Novara (Italy); Garonna, A. [TERA Foundation-via G. Puccini 11, 28100 Novara (Italy); Ecole Polytechnique Federale Lausanne EPFL-1015 Lausanne (Switzerland); Verdu-Andres, S. [TERA Foundation-via G. Puccini 11, 28100 Novara (Italy); Instituto de Fisica Corpuscular IFIC (CSIC-UVEG)-Paterna, 46071 Valencia (Spain); Wegner, R. [CERN- 1211 Geneva (Switzerland)

    2011-11-21

    The scientific community and the medical industries are putting a considerable effort into the design of compact, reliable and cheap accelerators for hadrontherapy. Up to now only circular accelerators are used to deliver beams with energies suitable for the treatment of deep seated tumors. The TERA Foundation has proposed and designed a hadrontherapy facility based on the cyclinac concept: a high gradient linear accelerator placed downstream of a cyclotron used as an injector. The overall length of the linac, and therefore its final cost, is almost inversely proportional to the average accelerating gradient achieved in the linac. TERA, in collaboration with the CLIC RF group, has started a high gradient test program. The main goal is to study the high gradient behavior of prototype cavities and to determine the appropriate linac operating frequency considering important issues such as machine reliability and availability of distributed power sources. A preliminary test of a 3 GHz cavity has been carried out at the beginning of 2010, giving encouraging results. Further investigations are planned before the end of 2011. A set of 5.7 GHz cavities is under production and will be tested in a near future. The construction and test of a multi-cell structure is also foreseen.

  16. TERA high gradient test program of RF cavities for medical linear accelerators

    Science.gov (United States)

    Degiovanni, A.; Amaldi, U.; Bonomi, R.; Garlasché, M.; Garonna, A.; Verdú-Andrés, S.; Wegner, R.

    2011-11-01

    The scientific community and the medical industries are putting a considerable effort into the design of compact, reliable and cheap accelerators for hadrontherapy. Up to now only circular accelerators are used to deliver beams with energies suitable for the treatment of deep seated tumors. The TERA Foundation has proposed and designed a hadrontherapy facility based on the cyclinac concept: a high gradient linear accelerator placed downstream of a cyclotron used as an injector. The overall length of the linac, and therefore its final cost, is almost inversely proportional to the average accelerating gradient achieved in the linac. TERA, in collaboration with the CLIC RF group, has started a high gradient test program. The main goal is to study the high gradient behavior of prototype cavities and to determine the appropriate linac operating frequency considering important issues such as machine reliability and availability of distributed power sources. A preliminary test of a 3 GHz cavity has been carried out at the beginning of 2010, giving encouraging results. Further investigations are planned before the end of 2011. A set of 5.7 GHz cavities is under production and will be tested in a near future. The construction and test of a multi-cell structure is also foreseen.

  17. Development of seismic technology and reliability based on vibration tests

    Energy Technology Data Exchange (ETDEWEB)

    Sasaki, Youichi [Nuclear Power Engineering Corp., Tokyo (Japan)

    1997-03-01

    This paper deals with some of the vibration tests and investigations on the seismic safety of nuclear power plants (NPPs) in Japan. To ensure the reliability of the seismic safety of nuclear power plants, nuclear power plants in Japan have been designed according to the Technical Guidelines for Aseismic Design of Nuclear Power Plants. This guideline has been developed based on technical date base and findings which were obtained from many vibration tests and investigations. Besides the tests for the guideline, proving tests on seismic reliability of operating nuclear power plants equipment and systems have been carried out. In this paper some vibration tests and their evaluation results are presented. They have crucially contributed to develop the guideline. (J.P.N.)

  18. Engineering Area Investigation of Reliability Attributes and Accelerated Stress Factors on Terrestrial Solar Cells

    Science.gov (United States)

    Lathrop, J. W.; Prince, J. L.

    1979-01-01

    Results obtained include the definition of a simplified stress test schedule for terrestrial solar cells based on the work performed during the first program year, and the design and fabrication of improved jigs and fixtures for electrical measurement and stress testing. Implementation of these advanced techniques for accelerated stress testing is underway on three solar cell types. In addition, review of the literature on second quadrant phenomena was begun and some preliminary second-quadrant electrical measurements were performed. Results obtained at the first down time for 75 C B-T testing and biased and unbiased T-H pressure cooker testing of type F cells showed little or no degradation in electrical parameters. Significant physical effects (large solder bubbles) were noted for type F cells subjected to the pressure cooker stress test.

  19. The Accelerated Test of Chloride Permeability of Concrete

    Institute of Scientific and Technical Information of China (English)

    TAN Ke-feng; ODD E Gjφrv

    2003-01-01

    The availability of accelerated chloride permeability test and the effect of w/c ratio, incorporation of silica fume, maximum aggregate size and aggregate type on the chloride permeability were studied. The mathematic analysis certifies that there is a linear relationship between accelerated test and natural diffusion. Test results show that the chloride permeability of concrete increases as w/c ratio increases whilst a limited amount of replacement of cement with silica fume, the chloride permeability decreases dramatically. The maximum aggregate size in the range of 8 to 25 mm seems also affect chloride permeability but with a much less significant level. The chloride permeability of silica fume lightweight aggregate concrete is very low, especially the concrete made with dry lightweight concrete. The chloride permeability can be evaluated by this accelerated test method.

  20. Optimization of the reliability of ADS accelerators in the framework of the EUROTRANS project; Optimisation de la fiabilite des accelerateurs ADS dans le cadre du projet EUROTRANS

    Energy Technology Data Exchange (ETDEWEB)

    Lucija, Lukovac

    2007-07-01

    In order to limit the number of thermal shocks in the spallation targets and in the core of an ADS (Accelerator Driven System), it is necessary to limit the number of failures of the beam accelerating system. This article presents the improvements in terms of reliability for 2 sub-systems of the ADS: the control system that is in charge of the RF power equipment that delivers the energy necessary to the accelerating system and the power coupler whose purpose is to transfer energy from RF generator to the accelerating cavities. The digitalization of the control system has allowed the application of a compensation method: if one of the cavities fails, the neighbouring cavities are regulated to limit the consequences of the failure on the beam. As for the power coupler, the ceramic window has been designed with great care. The improvements will be tested on 2 prototypes that are being built. (A.C.)

  1. Study of variables for accelerating lifetime testing of SOFCs

    DEFF Research Database (Denmark)

    Ploner, Alexandra; Hagen, Anke; Hauch, Anne

    at a generally accepted result. First accelerated testing approaches were performed under non-steady operation conditions (current cycling,temperature cycling) by different researchers [1, 2]. However, cycling conditions seemed to have no significant impact on degradation mechanisms. Furthermore, tests done...

  2. Gearbox Reliability Collaborative Phase 3 Gearbox 2 Test Plan

    Energy Technology Data Exchange (ETDEWEB)

    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.

  3. Practical Guidelines for Valid and Reliable Youth Fitness Testing

    Science.gov (United States)

    Mahar, Matthew T.; Rowe, David A.

    2008-01-01

    Accurate measures of youth fitness are needed by researchers and practitioners. Evidence of validity and reliability are essential before results of youth fitness tests can be used to make sound decisions. This article describes a three-stage paradigm for validation research and provides guidance for conducting and understanding norm-referenced…

  4. MEMS Reliability: Infrastructure, Test Structures, Experiments, and Failure Modes

    Energy Technology Data Exchange (ETDEWEB)

    TANNER,DANELLE M.; SMITH,NORMAN F.; IRWIN,LLOYD W.; EATON,WILLIAM P.; HELGESEN,KAREN SUE; CLEMENT,J. JOSEPH; MILLER,WILLIAM M.; MILLER,SAMUEL L.; DUGGER,MICHAEL T.; WALRAVEN,JEREMY A.; PETERSON,KENNETH A.

    2000-01-01

    The burgeoning new technology of Micro-Electro-Mechanical Systems (MEMS) shows great promise in the weapons arena. We can now conceive of micro-gyros, micro-surety systems, and micro-navigators that are extremely small and inexpensive. Do we want to use this new technology in critical applications such as nuclear weapons? This question drove us to understand the reliability and failure mechanisms of silicon surface-micromachined MEMS. Development of a testing infrastructure was a crucial step to perform reliability experiments on MEMS devices and will be reported here. In addition, reliability test structures have been designed and characterized. Many experiments were performed to investigate failure modes and specifically those in different environments (humidity, temperature, shock, vibration, and storage). A predictive reliability model for wear of rubbing surfaces in microengines was developed. The root causes of failure for operating and non-operating MEMS are discussed. The major failure mechanism for operating MEMS was wear of the polysilicon rubbing surfaces. Reliability design rules for future MEMS devices are established.

  5. Reliability Evaluation of Concentric Butterfly Valve Using Statistical Hypothesis Test

    Energy Technology Data Exchange (ETDEWEB)

    Chang, Mu Seong; Choi, Jong Sik; Choi, Byung Oh; Kim, Do Sik [Korea Institute of Machinery and Materials, Daejeon (Korea, Republic of)

    2015-12-15

    A butterfly valve is a type of flow-control device typically used to regulate a fluid flow. This paper presents an estimation of the shape parameter of the Weibull distribution, characteristic life, and B10 life for a concentric butterfly valve based on a statistical analysis of the reliability test data taken before and after the valve improvement. The difference in the shape and scale parameters between the existing and improved valves is reviewed using a statistical hypothesis test. The test results indicate that the shape parameter of the improved valve is similar to that of the existing valve, and that the scale parameter of the improved valve is found to have increased. These analysis results are particularly useful for a reliability qualification test and the determination of the service life cycles.

  6. VALIDITY AND RELIABILITY OF CLINICAL TESTS FOR THE SACROILIAC JOINT

    OpenAIRE

    2002-01-01

    Background: The sacroiliac joint (SIJ) can be a source of low back pain. The complexity of the system involving the SIJ and the varied SIJ pain referral pattern makes it difficult to clinically assess SIJ dysfunction. Despite the emergence of detail of the SIJ complex, the basis of the clinical tests has not been thoroughly investigated. Objective: To review the literature from the last decade dealing with the validity and reliability of clinical tests for SIJ dysfunction in order to determin...

  7. Gearbox Reliability Collaborative Phase 3 Gearbox 3 Test Plan

    Energy Technology Data Exchange (ETDEWEB)

    Keller, Jonathan [National Renewable Energy Lab. (NREL), Golden, CO (United States); Wallen, Robb [National Renewable Energy Lab. (NREL), Golden, CO (United States)

    2016-10-01

    This document describes the Phase 3 test plan for the Gearbox Reliability Collaborative Gearbox #3. The primary test objective is to measure the planetary load sharing characteristics in the same conditions as the original gearbox design. If the measured load-sharing characteristics are close to the design model, the projected three-times improvement in planetary section predicted fatigue life and the efficacy of preloaded tapered roller bearings in mitigating the planetary bearing fatigue failure mode will have been demonstrated.

  8. Gearbox Reliability Collaborative Phase 3 Gearbox 2 Test Report

    Energy Technology Data Exchange (ETDEWEB)

    Keller, Jonathan; Wallen, Robb

    2015-06-10

    Many gearboxes in wind turbines have not been achieving their expected design life [1]; they do, however, commonly meet or exceed the design criteria specified in current standards in the gear, bearing, and wind turbine industry as well as third-party certification criteria. The cost of gearbox replacements and rebuilds, as well as the downtime associated with these failures, has elevated the cost of wind energy. In 2006, the U.S. Department of Energy established the National Renewable Energy Laboratory (NREL) Gearbox Reliability Collaborative (GRC). Its key goal is to understand the root causes of premature gearbox failures and improve their reliability [2]. The GRC is examining a hypothesis that the gap between design-estimated and actual wind turbine gearbox reliability is caused by underestimation of loads, inaccurate design tools, the absence of critical elements in the design process, or insufficient testing. This test report describes the recent tests of GRC gearbox (GB) 2 in the National Wind Technology Center (NWTC) dynamometer and documents any modifications to the original test plan [3]. In this manner, it serves as a guide for interpreting the publicly released data sets with brief analyses to illustrate the data. Specific objectives of the test were to assess the effect of dynamic nontorque load (NTL) on the planetary section, generator misalignment on the highspeed shaft (HSS), and field representative conditions on the gearbox in general. Detailed analysis of those test objectives will be presented in subsequent publications.

  9. Empirical Measurement of the Software Testing and Reliability

    Institute of Scientific and Technical Information of China (English)

    Zou Feng-zhong; Xu Ren-zuo

    2004-01-01

    The meanings of parameters of software reliability models are investigated in terms of the process of the software testing and in terms of other measurements of software. Based on the investigation, the empirical estimation of the parameters is addressed. On one hand, these empirical estimates are also measurements of the software, which can be used to control and to optimize the process of the software development. On the other hand, by treating these empirical estimates as Bayes priors, software reliability models are extended such that the engineers' experience can be integrated into and hence to improve the models.

  10. On the reliability of microvariability tests in quasars

    Energy Technology Data Exchange (ETDEWEB)

    De Diego, José A., E-mail: jdo@astro.unam.mx [Instituto de Astronomía, Universidad Nacional Autónoma de México, Avenida Universidad 3000, Ciudad Universitaria, C.P. 04510, Distrito Federal, MexicoAND (Mexico); Instituto de Astrofísica de Canarias-Universidad de La Laguna, CEI Canarias: Campus Atlántico Tricontinental, E-38205 La Laguna, Tenerife (Spain)

    2014-11-01

    Microvariations probe the physics and internal structure of quasars. Unpredictability and small flux variations make this phenomenon elusive and difficult to detect. Variance-based probes such as the C and F tests, or a combination of both, are popular methods to compare the light curves of the quasar and a comparison star. Recently, detection claims in some studies have depended on the agreement of the results of the C and F tests, or of two instances of the F-test, for rejecting the non-variation null hypothesis. However, the C-test is a non-reliable statistical procedure, the F-test is not robust, and the combination of tests with concurrent results is anything but a straightforward methodology. A priori power analysis calculations and post hoc analysis of Monte Carlo simulations show excellent agreement for the analysis of variance test to detect microvariations as well as the limitations of the F-test. Additionally, the combined tests yield correlated probabilities that make the assessment of statistical significance unworkable. However, it is possible to include data from several field stars to enhance the power in a single F-test, increasing the reliability of the statistical analysis. This would be the preferred methodology when several comparison stars are available. An example using two stars and the enhanced F-test is presented. These results show the importance of using adequate methodologies and avoiding inappropriate procedures that can jeopardize microvariability detections. Power analysis and Monte Carlo simulations are useful tools for research planning, as they can demonstrate the robustness and reliability of different research approaches.

  11. Design and test of a superconducting magnet in a linear accelerator for an Accelerator Driven Subcritical System

    Energy Technology Data Exchange (ETDEWEB)

    Peng, Quanling, E-mail: pengql@ihep.ac.cn [Institute of High Energy Physics, Chinese Academy of Sciences, Beijing 100049 (China); Xu, Fengyu [Harbin Institute of Technology, Heilongjiang 150006 (China); Wang, Ting [Beijing Huantong Special Equipment Co., LTD, Beijing 100192 (China); Yang, Xiangchen [Institute of High Energy Physics, Chinese Academy of Sciences, Beijing 100049 (China); Chen, Anbin [Harbin Institute of Technology, Heilongjiang 150006 (China); Wei, Xiaotao [Beijing Huantong Special Equipment Co., LTD, Beijing 100192 (China); Gao, Yao; Hou, Zhenhua; Wang, Bing; Chen, Yuan; Chen, Haoshu [Institute of High Energy Physics, Chinese Academy of Sciences, Beijing 100049 (China)

    2014-11-11

    A batch superconducting solenoid magnet for the ADS proton linear accelerator has been designed, fabricated, and tested in a vertical dewar in Sept. 2013. A total of ten superconducting magnets will be installed into two separate cryomodules. Each cryomodule contains six superconducting spoke RF cavities for beam acceleration and five solenoid magnets for beam focusing. The multifunction superconducting magnet contains a solenoid for beam focusing and two correctors for orbit correction. The design current for the solenoid magnet is 182 A. A quench performance test shows that the operating current of the solenoid magnet can reach above 300 A after natural quenching on three occasions during current ramping (260 A, 268 A, 308 A). The integrated field strength and leakage field at the nearby superconducting spoke cavities all meet the design requirements. The vertical test checked the reliability of the test dewar and the quench detection system. This paper presents the physical and mechanical design of the batch magnets, the quench detection technique, field measurements, and a discussion of the residual field resulting from persistent current effects.

  12. RELIABILITY AND VALIDITY TESTING OF AN ARCHERY CHRONOMETER

    Directory of Open Access Journals (Sweden)

    Hayri Ertan

    2005-06-01

    Full Text Available Keeping the arrow velocity constant during consecutive shots and responding to "clicker's fall" are considered to be an important feature of archery performance. A specially designed device called an archery chronometer was developed to measure the reaction time of an archer to clicker's fall, arrow velocity, and external factors that may affect arrow velocity. The purposes of this study were to test (1 the validity of Clicker Reaction Time (CRT measurer, and (2 the reliability of CRT in accordance with the Flying Time (FT/Average Speed (AS, temperature (TEMP, wind speed (WS and wind direction (WD measurements. 20 elite archers participated in this study. The Reaction Time (RT, which was derived from EMG values and CRT from the archery chronometer were correlated to test the validity of the CRT measurer. The test re-test method was applied to test the reliability of archery chronometer. CRT scores were related with RT scores (r = .787, p < 0.01. The archery chronometer was valid in terms of predicting reaction time. The device was found to be reliable in measuring CRT, AS, FT, WS, WD, and TEMP. It was concluded that archery chronometer could be used for technical evaluation and enhancing ones shooting technique in archery.

  13. Test-retest reliability of knee kinesthesia in healthy adults

    Directory of Open Access Journals (Sweden)

    Flenhagen Johan

    2007-07-01

    Full Text Available Abstract Background Sensory information from mechanoreceptors in the skin, muscles, tendons, and joint structures plays an important role in joint stability. A joint injury can lead to disruption of the sensory system, which can be measured by proprioceptive acuity. When evaluating proprioception, assessment tools need to be reliable. The aim of this study was to assess the test-retest reliability of a device designed to measure knee proprioception. Methods Twenty-four uninjured individuals (14 women and 10 men were examined with regard to test-retest reliability of knee kinesthesia, measured by the threshold to detection of passive motion (TDPM. Measurements were performed towards extension and flexion from the two starting positions, 20 degrees and 40 degrees knee joint flexion, giving four variables. The mean difference between test and retest together with the 95% confidence interval (test 2 minus test 1, the intraclass correlation coefficient (ICC2,1, and Bland and Altman graphs with limits of agreement, were used as statistical methods for assessing test-retest reliability. Results The intraclass correlation coefficients ranged from 0.59 to 0.70 in all variables except one. No difference was found between test and retest in three of the four TDPM variables. TDPM would need to decrease between 10% and 38%, and increase between 17% and 24% in groups of uninjured subjects to be 95% confident of detecting a real change. The limits of agreement were rather wide in all variables. The variables associated with the 20-degree starting position tended to have higher intraclass correlation coefficients and narrower limits of agreement than those associated with 40 degrees. Conclusion Three TDPM variables were considered reliable for observing change in groups of subjects without pathology. However, the limits of agreement revealed that small changes in an individual's performance cannot be detected. The higher intraclass correlation coefficients and

  14. Quick setup of unit test for accelerator controls system

    Energy Technology Data Exchange (ETDEWEB)

    Fu, W.; D' Ottavio, T.; Gassner, D.; Nemesure, S.; Morris, J.

    2011-03-28

    Testing a single hardware unit of an accelerator control system often requires the setup of a program with graphical user interface. Developing a dedicated application for a specific hardware unit test could be time consuming and the application may become obsolete after the unit tests. This paper documents a methodology for quick design and setup of an interface focused on performing unit tests of accelerator equipment with minimum programming work. The method has three components. The first is a generic accelerator device object (ADO) manager which can be used to setup, store, and log testing controls parameters for any unit testing system. The second involves the design of a TAPE (Tool for Automated Procedure Execution) sequence file that specifies and implements all te testing and control logic. The sting third is the design of a PET (parameter editing tool) page that provides the unit tester with all the necessary control parameters required for testing. This approach has been used for testing the horizontal plane of the Stochastic Cooling Motion Control System at RHIC.

  15. Bayesian Approach for Constant-Stress Accelerated Life Testing for Kumaraswamy Weibull Distribution with Censoring

    Directory of Open Access Journals (Sweden)

    Abeer Abd-Alla EL-Helbawy

    2016-09-01

    Full Text Available The accelerated life tests provide quick information on the life time distributions by testing materials or products at higher than basic conditional levels of stress such as pressure, high temperature, vibration, voltage or load to induce failures. In this paper, the acceleration model assumed is log linear model. Constant stress tests are discussed based on Type I and Type II censoring. The Kumaraswmay Weibull distribution is used. The estimators of the parameters, reliability, hazard rate functions and p-th percentile at normal condition, low stress, and high stress are obtained. In addition, credible intervals for parameters of the models are constructed. Optimum test plan are designed. Some numerical studies are used to solve the complicated integrals such as Laplace and Markov Chain Monte Carlo methods.

  16. Next Linear Collider Test Accelerator conceptual design report

    Energy Technology Data Exchange (ETDEWEB)

    1993-08-01

    This document presents the scientific justification and the conceptual design for the {open_quotes}Next Linear Collider Test Accelerator{close_quotes} (NLCTA) at SLAC. The goals of the NLCTA are to integrate the new technologies of X-band accelerator structures and rf systems being developed for the Next Linear Collider, to measure the growth of the {open_quotes}dark current{close_quotes} generated by rf field emission in the accelerator, to demonstrate multi-bunch beam-loading energy compensation and suppression of higher-order deflecting modes, and to measure any transverse components of the accelerating field. The NLCTA will be a 42-meter-long beam line consisting, consecutively, of a thermionic-cathode gun, an X-band buncher, a magnetic chicane, six 1.8-meter-long sections of 11.4-GHz accelerator structure, and a magnetic spectrometer. Initially, the unloaded accelerating gradient will be 50 MV/m. A higher-gradient upgrade option eventually would increase the unloaded gradient to 100 MV/m.

  17. The BNL Accelerator Test Facility and experimental program

    Energy Technology Data Exchange (ETDEWEB)

    Ben-Zvi, I. (Brookhaven National Lab., Upton, NY (United States) State Univ. of New York, Stony Brook, NY (United States). Dept. of Physics)

    1991-01-01

    The Accelerator Test Facility (ATF) at BNL is a users' facility for experiments in Accelerator and Beam Physics. The ATF provides high brightness electron beams and high power laser pulses synchronized to the electron beam, suitable for studies of new methods of high gradient acceleration and state of the art free electron lasers. The electrons are produced by a laser photocathode rf gun and accelerated to 50 to 100 MeV by two traveling wave accelerator sections. The lasers include a 10 mJ, 10 ps Nd:YAG laser and a 100 mJ, 10 ps CO{sub 2} laser. A number of users from National Laboratories, universities and industry take part in experiments at the ATF. The experimental program includes various acceleration schemes, Free-Electron Laser experiments and a program on the development of high brightness electron beams. The AFT's experimental program commenced in early 1991 at an energy of about 4 MeV. The full program, with 50 MeV and the High power laser will begin operation this year. 28 refs., 4 figs.

  18. The BNL Accelerator Test Facility and experimental program

    Energy Technology Data Exchange (ETDEWEB)

    Ben-Zvi, I. [Brookhaven National Lab., Upton, NY (United States)]|[State Univ. of New York, Stony Brook, NY (United States). Dept. of Physics

    1992-09-01

    The Accelerator Test Facility (ATF) at BNL is a users` facility for experiments in Accelerator and Beam Physics. The ATF provides high brightness electron beams and high-power laser pulses synchronized to the electron beam, suitable for studies of new methods of high-gradient acceleration and state-of-the-art Free-Electron Lasers. The electrons are produced by a laser photocathode rf gun and accelerated to 50 MeV by two traveling wave accelerator sections. The lasers include a 10 mJ, 10 ps ND:YAG laser and a 500 mJ, 10 to 100 ps C0{sub 2} laser. A number of users from National Laboratories, universities and industry take part in experiments at the ATF. The experimental program includes various laser acceleration schemes, Free-Electron Laser experiments and a program on the development of high-brightness electron beams. The ATF`s experimental program commenced in early 1991 at an energy of about 4 MeV. The full program, with 50 MeV and the high-power laser will begin operation this year.

  19. The BNL Accelerator Test Facility and experimental program

    Energy Technology Data Exchange (ETDEWEB)

    Ben-Zvi, I. (Brookhaven National Lab., Upton, NY (United States) State Univ. of New York, Stony Brook, NY (United States). Dept. of Physics)

    1992-01-01

    The Accelerator Test Facility (ATF) at BNL is a users' facility for experiments in Accelerator and Beam Physics. The ATF provides high brightness electron beams and high-power laser pulses synchronized to the electron beam, suitable for studies of new methods of high-gradient acceleration and state-of-the-art Free-Electron Lasers. The electrons are produced by a laser photocathode rf gun and accelerated to 50 MeV by two traveling wave accelerator sections. The lasers include a 10 mJ, 10 ps ND:YAG laser and a 500 mJ, 10 to 100 ps C0{sub 2} laser. A number of users from National Laboratories, universities and industry take part in experiments at the ATF. The experimental program includes various laser acceleration schemes, Free-Electron Laser experiments and a program on the development of high-brightness electron beams. The ATF's experimental program commenced in early 1991 at an energy of about 4 MeV. The full program, with 50 MeV and the high-power laser will begin operation this year.

  20. Design of Octupole Channel for Integrable Optics Test Accelerator

    Energy Technology Data Exchange (ETDEWEB)

    Antipov, Sergey [Chicago U.; Carlson, Kermit [Fermilab; Castellotti, Riccardo [Unlisted, IT; Valishev, Alexander [Fermilab; Wesseln, Steven [Fermilab

    2016-06-01

    We present the design of octupole channel for Integrable Optics Test Accelerator (IOTA). IOTA is a test accelerator at Fermilab, aimed to conduct research towards high-intensity machines. One of the goals of the project is to demonstrate high nonlinear betatron tune shifts while retaining large dynamic aperture in a realistic accelerator design. At the first stage the tune shift will be attained with a special channel of octupoles, which creates a variable octupole potential over a 1.8 m length. The channel consists of 18 identical air-cooled octupole magnets. The magnets feature a simple low-cost design, while meeting the requirements on maximum gradient - up to 1.4 kG/cm³, and field quality - strength of harmonics below 1%. Numerical simulations show that the channel is capable of producing a nonlinear tune shift of 0.08 without restriction of dynamic aperture of the ring.

  1. Reliability Testing the Die-Attach of CPV Cell Assemblies

    Energy Technology Data Exchange (ETDEWEB)

    Bosco, N.; Sweet, C.; Kurtz, S.

    2011-02-01

    Results and progress are reported for a course of work to establish an efficient reliability test for the die-attach of CPV cell assemblies. Test vehicle design consists of a ~1 cm2 multijunction cell attached to a substrate via several processes. A thermal cycling sequence is developed in a test-to-failure protocol. Methods of detecting a failed or failing joint are prerequisite for this work; therefore both in-situ and non-destructive methods, including infrared imaging techniques, are being explored as a method to quickly detect non-ideal or failing bonds.

  2. Reliability of diagnostic tests in rotator cuff muscle pathology

    Directory of Open Access Journals (Sweden)

    R. Sadenbergh

    2006-02-01

    Full Text Available Background: Several tests to assist it in the diagnoses of rota-tor cuff impairment have been described in the literature but controversystill exists as to the accuracy of these tests. A study was therefore conducted to determine the reliability of the rotator cuff muscle tests (empty can, full can, lift off and external rotation as a diagnostic tool.Methodology: Fifty three patients experiencing shoulder pain were assessedusing manual muscle tests (empty can; full can; lift off and external rotationtests. Both pain and weakness were recorded using numerical scales adapted from tests performed by Itoi et al, (1999. These results were compared to ultrasonic diagnoses made by a surgeon. Informed consent was obtained and anonymity was ensured for all participants.Results: A test was false positive when ultrasonic diagnosis indicated no tear in the muscle (although oedema or calcification may have been present, but the manual muscle test was positive regarding pain and weakness. A test on the other hand was false negative when the ultrasonic diagnosis indicated a muscle tear but the manual muscle tests indicated no pain or muscle weakness. Reliability was tested using sensitivity and specificity tests. The sensitivity of all four tests was high (80%, but the specificity was low (20% to 40%, implying that a large number of false positive diagnoses can be made. The major contributors to the false positive results were sub-acromial sub-deltoid bursitis and a decreased acromio-humeral space. When considering pain alone for a positive result the correlation increased a  little, however, taking both pain and muscle weakness into account, the correlation increased even more.Conclusion: The manual muscle tests were not as reliable as expected, but concurrent pathologies may be the main factor influencing the results of the tests. The combination of muscle strength and pain could be recommendedas criteria for a positive test. The empty can and full can

  3. Test of the law of gravitation at small accelerations

    Energy Technology Data Exchange (ETDEWEB)

    Meyer, H. [Wuppertal Univ. (Germany); Lohrmann, E.; Schubert, S. [Hamburg Univ. (Germany). Inst. fuer Experimentalphysik; Bartel, W.; Glazov, A.; Loehr, B.; Niebuhr, C.; Wuensch, E. [Deutsches Elektronen-Synchrotron (DESY), Hamburg (Germany); Joensson, L.; Kempf, G. [Lund Univ. (Sweden)

    2011-12-15

    Newton's Law of Gravitation has been tested at small values a of the acceleration, down to a {approx}10{sup -10} ms{sup -2}, the approximate value of MOND's constant a{sub 0}. No deviations were found. (orig.)

  4. Reliability of Maximal Strength Testing in Novice Weightlifters

    Science.gov (United States)

    Loehr, James A.; Lee, Stuart M. C.; Feiveson, Alan H.; Ploutz-Snyder, Lori L.

    2009-01-01

    The one repetition maximum (1RM) is a criterion measure of muscle strength. However, the reliability of 1RM testing in novice subjects has received little attention. Understanding this information is crucial to accurately interpret changes in muscle strength. To evaluate the test-retest reliability of a squat (SQ), heel raise (HR), and deadlift (DL) 1RM in novice subjects. Twenty healthy males (31 plus or minus 5 y, 179.1 plus or minus 6.1 cm, 81.4 plus or minus 10.6 kg) with no weight training experience in the previous six months participated in four 1RM testing sessions, with each session separated by 5-7 days. SQ and HR 1RM were conducted using a smith machine; DL 1RM was assessed using free weights. Session 1 was considered a familiarization and was not included in the statistical analyses. Repeated measures analysis of variance with Tukey fs post-hoc tests were used to detect between-session differences in 1RM (p.0.05). Test-retest reliability was evaluated by intraclass correlation coefficients (ICC). During Session 2, the SQ and DL 1RM (SQ: 90.2 }4.3, DL: 75.9 }3.3 kg) were less than Session 3 (SQ: 95.3 }4.1, DL: 81.5 plus or minus 3.5 kg) and Session 4 (SQ: 96.6 }4.0, DL: 82.4 }3.9 kg), but there were no differences between Session 3 and Session 4. HR 1RM measured during Session 2 (150.1 }3.7 kg) and Session 3 (152.5 }3.9 kg) were not different from one another, but both were less than Session 4 (157.5 }3.8 kg). The reliability (ICC) of 1RM measures for Sessions 2-4 were 0.88, 0.83, and 0.87, for SQ, HR, and DL, respectively. When considering only Sessions 3 and 4, the reliability was 0.93, 0.91, and 0.86 for SQ, HR, and DL, respectively. One familiarization session and 2 test sessions (for SQ and DL) were required to obtain excellent reliability (ICC greater than or equal to 0.90) in 1RM values with novice subjects. We were unable to attain this level of reliability following 3 HR testing sessions therefore additional sessions may be required to obtain an

  5. Final report : testing and evaluation for solar hot water reliability.

    Energy Technology Data Exchange (ETDEWEB)

    Caudell, Thomas P. (University of New Mexico, Albuquerque, NM); He, Hongbo (University of New Mexico, Albuquerque, NM); Menicucci, David F. (Building Specialists, Inc., Albuquerque, NM); Mammoli, Andrea A. (University of New Mexico, Albuquerque, NM); Burch, Jay (National Renewable Energy Laboratory, Golden CO)

    2011-07-01

    Solar hot water (SHW) systems are being installed by the thousands. Tax credits and utility rebate programs are spurring this burgeoning market. However, the reliability of these systems is virtually unknown. Recent work by Sandia National Laboratories (SNL) has shown that few data exist to quantify the mean time to failure of these systems. However, there is keen interest in developing new techniques to measure SHW reliability, particularly among utilities that use ratepayer money to pay the rebates. This document reports on an effort to develop and test new, simplified techniques to directly measure the state of health of fielded SHW systems. One approach was developed by the National Renewable Energy Laboratory (NREL) and is based on the idea that the performance of the solar storage tank can reliably indicate the operational status of the SHW systems. Another approach, developed by the University of New Mexico (UNM), uses adaptive resonance theory, a type of neural network, to detect and predict failures. This method uses the same sensors that are normally used to control the SHW system. The NREL method uses two additional temperature sensors on the solar tank. The theories, development, application, and testing of both methods are described in the report. Testing was performed on the SHW Reliability Testbed at UNM, a highly instrumented SHW system developed jointly by SNL and UNM. The two methods were tested against a number of simulated failures. The results show that both methods show promise for inclusion in conventional SHW controllers, giving them advanced capability in detecting and predicting component failures.

  6. Reliability of wind turbine blades: An overview of materials testing

    DEFF Research Database (Denmark)

    Holmes, John W.; Sørensen, Bent F.; Brøndsted, Povl

    2007-01-01

    an understanding of how damage develops in composite structures, composite materials and adhesives. Designing reliable wind turbine blades also requires the further development of laboratory scale and full scale test methods to evaluate the structural response and durability of new materials under various loading...... and environmental conditions. This paper highlights recent advances in methods used to characterize adhesive joints in wind turbine blades and the manner in which laboratory data is used to predict the structural response of wind turbine blades....

  7. Acceleration tests of a 3 GHz proton linear accelerator (LIBO) for hadrontherapy

    Energy Technology Data Exchange (ETDEWEB)

    De Martinis, C., E-mail: carlo.demartinis@mi.infn.it [University of Milan and INFN, Milan (Italy); Giove, D. [University of Milan and INFN, Milan (Italy); Amaldi, U.; Berra, P.; Crandall, K.; Mauri, M.; Weiss, M.; Zennaro, R. [TERA Foundation, Novara (Italy); Rosso, E.; Szeless, B.; Vretenar, M. [CERN, Geneva (Switzerland); Masullo, M.R.; Vaccaro, V. [University and INFN of Naples (Italy); Calabretta, L.; Rovelli, A. [INFN-LNS Catania (Italy)

    2012-07-21

    This paper describes the acceleration tests performed at the Catania LNS Laboratory on a 3 GHz linac module of the side coupled type, which boosts the proton energy of a beam extracted from a cyclotron from 62 to 72 MeV. The output proton energy was measured with two devices: a NaI(Tl) crystal and a bending magnet. The experimental spectra are in good agreement with the calculated ones. From their shape it is obtained that (18{+-}3.0)% of the transmitted protons fall in a {+-}2 MeV interval centered around 72 MeV. This result is in good agreement with the 20% value derived from the simulation of the acceleration process. The measured energy of the accelerated protons was used to check that the shunt impedance of the structure is equal to the computed one within 3%. This was the first time that a 3 GHz structure has been used to accelerate protons, and the results of the tests have demonstrated that a high frequency linac can be used as a cyclotron booster.

  8. Acceleration tests of a 3 GHz proton linear accelerator (LIBO) for hadrontherapy

    Science.gov (United States)

    De Martinis, C.; Giove, D.; Amaldi, U.; Berra, P.; Crandall, K.; Mauri, M.; Weiss, M.; Zennaro, R.; Rosso, E.; Szeless, B.; Vretenar, M.; Masullo, M. R.; Vaccaro, V.; Calabretta, L.; Rovelli, A.

    2012-07-01

    This paper describes the acceleration tests performed at the Catania LNS Laboratory on a 3 GHz linac module of the side coupled type, which boosts the proton energy of a beam extracted from a cyclotron from 62 to 72 MeV. The output proton energy was measured with two devices: a NaI(Tl) crystal and a bending magnet. The experimental spectra are in good agreement with the calculated ones. From their shape it is obtained that (18±3.0)% of the transmitted protons fall in a ±2 MeV interval centered around 72 MeV. This result is in good agreement with the 20% value derived from the simulation of the acceleration process. The measured energy of the accelerated protons was used to check that the shunt impedance of the structure is equal to the computed one within 3%. This was the first time that a 3 GHz structure has been used to accelerate protons, and the results of the tests have demonstrated that a high frequency linac can be used as a cyclotron booster.

  9. Reliability of the Timed Up and Go Test in Fibromyalgia.

    Science.gov (United States)

    Collado-Mateo, Daniel; Domínguez-Muñoz, Francisco J; Adsuar, José C; Merellano-Navarro, Eugenio; Olivares, Pedro R; Gusi, Narcis

    2016-10-26

    To evaluate the test-retest reliability of the timed-up and go test using manual and automatic chronometer (chronopic) in women with fibromyalgia. Cross-sectional study with convenience sample. A total of 49 women with FM, aged 50.20 ± 10.01, participated in the study. The Intraclass correlation coefficient was 0.935 with the manual stopwatch, and 0.955 with the chronopic. The smallest real difference using manual stopwatch was 9.327%, whereas for the timed-up and go using the chronopic was 7.708%. Mean of the three repetitions was significantly different (p = .005) between both chronometers. Timed-up and go is a reliable physical fitness test for assessing agility/dynamic balance in women with fibromyalgia. The reliability is higher when the time is tracked using an automatic chronometer, which is easy to use and not expensive in terms of time and money, the use of this device is recommended in the nursing practice. © 2016 Association of Rehabilitation Nurses.

  10. Diagnostic reliability of MMPI-2 computer-based test interpretations.

    Science.gov (United States)

    Pant, Hina; McCabe, Brian J; Deskovitz, Mark A; Weed, Nathan C; Williams, John E

    2014-09-01

    Reflecting the common use of the MMPI-2 to provide diagnostic considerations, computer-based test interpretations (CBTIs) also typically offer diagnostic suggestions. However, these diagnostic suggestions can sometimes be shown to vary widely across different CBTI programs even for identical MMPI-2 profiles. The present study evaluated the diagnostic reliability of 6 commercially available CBTIs using a 20-item Q-sort task developed for this study. Four raters each sorted diagnostic classifications based on these 6 CBTI reports for 20 MMPI-2 profiles. Two questions were addressed. First, do users of CBTIs understand the diagnostic information contained within the reports similarly? Overall, diagnostic sorts of the CBTIs showed moderate inter-interpreter diagnostic reliability (mean r = .56), with sorts for the 1/2/3 profile showing the highest inter-interpreter diagnostic reliability (mean r = .67). Second, do different CBTIs programs vary with respect to diagnostic suggestions? It was found that diagnostic sorts of the CBTIs had a mean inter-CBTI diagnostic reliability of r = .56, indicating moderate but not strong agreement across CBTIs in terms of diagnostic suggestions. The strongest inter-CBTI diagnostic agreement was found for sorts of the 1/2/3 profile CBTIs (mean r = .71). Limitations and future directions are discussed. PsycINFO Database Record (c) 2014 APA, all rights reserved.

  11. Reliability of indicators of nursing care quality: testing interexaminer agreement and reliability

    Directory of Open Access Journals (Sweden)

    Dagmar Willamowius Vituri

    2014-04-01

    Full Text Available OBJECTIVE: this study sought to test the interexaminer agreement and reliability of 15 indicators of nursing care quality.METHODS: this was a quantitative, methodological, experimental, and applied study conducted at a large, tertiary, public teaching hospital in the state of Paraná. For data analysis, the Kappa (k statistic was applied to the categorical variables - indicators 1 to 11 and 15 - and the interclass correlation coefficient (ICC to the continuous variables - indicators 12, 13, and 14, with the corresponding 95% confidence intervals. The categorical data were analyzed using the Lee software, elaborated by the Laboratory of Epidemiology and Statistics of Dante Pazzanese Institute of Cardiology - Brazil, and the continuous data were assessed using BioEstat 5.0.RESULTS: the k-statistic results indicated excellent agreement, which was statistically significant, and the values of the ICC denoted excellent and statistically significant reproducibility/agreement relative to the investigated indicators.CONCLUSION: the investigated indicators exhibited excellent reliability and reproducibility, thus showing that it is possible to formulate valid and reliable assessment instruments for the management of nursing care.

  12. ACCELERATED AGING AND ELECTRICAL CONDUCTIVITY TESTS IN CRAMBE SEEDS

    Directory of Open Access Journals (Sweden)

    Juliana Joice Pereira Lima

    2015-02-01

    Full Text Available The aim of this study was to adapt the methodology of the accelerated aging and electrical conductivity tests for determination of physiological potential in crambe seeds. Six seed lots of crambe (cv. FMS Brilhante were subjected to determination of moisture content, germination test, first count germination, emergence, and emergence speed index. For the accelerated aging test, the traditional methodology was used with water, and with a saturated potassium chloride and sodium chloride solution in three periods of exposure (24, 48, and 72 hours at 41°C; the electrical conductivity test was performed with four pre-soaking treatments (0, 2, 4, and 8 hours and four soaking periods (4, 8, 16, and 24 hours at 25°C. The accelerated aging test with water for 72 hours and the electrical conductivity test with 2 hours of pre-soaking and assessment after 16 hours were effective for classification of the crambe seed lots in regard to physiological quality.

  13. Test-retest reliability of the Frankfurt Complaint Questionnaire.

    Science.gov (United States)

    Loas, Gwenolé; Yon, Valerie; Monestès, Jean Louis; Cuesta, Manuel J

    2011-04-01

    Long-term reliability of the Frankfurt Complaint Questionnaire (FCQ) was investigated in two follow-up studies of participants with psychosis using a test-retest method. In the first study (N = 56), the duration of the follow-up ranged from 6 months to 2 years; Spearman rho was .62 for the abridged (18 items) Spanish version of the questionnaire. In Study 2 (N = 21), in participants with stable schizophrenia, the follow-up ranged from 8 to 11 years; test-retest Spearman rho was .83 for the French version of the questionnaire. Subjective experiences could constitute, in psychosis-prone people, traits or markers of psychotic vulnerability.

  14. NDT Reliability - Final Report. Reliability in non-destructive testing (NDT) of the canister components

    Energy Technology Data Exchange (ETDEWEB)

    Pavlovic, Mato; Takahashi, Kazunori; Mueller, Christina; Boehm, Rainer (BAM, Federal Inst. for Materials Research and Testing, Berlin (Germany)); Ronneteg, Ulf (Swedish Nuclear Fuel and Waste Management Co., Stockholm (Sweden))

    2008-12-15

    This report describes the methodology of the reliability investigation performed on the ultrasonic phased array NDT system, developed by SKB in collaboration with Posiva, for inspection of the canisters for permanent storage of nuclear spent fuel. The canister is composed of a cast iron insert surrounded by a copper shell. The shell is composed of the tube and the lid/base which are welded to the tube after the fuel has been place, in the tube. The manufacturing process of the canister parts and the welding process are described. Possible defects, which might arise in the canister components during the manufacturing or in the weld during the welding, are identified. The number of real defects in manufactured components have been limited. Therefore the reliability of the NDT system has been determined using a number of test objects with artificial defects. The reliability analysis is based on the signal response analysis. The conventional signal response analysis is adopted and further developed before applied on the modern ultrasonic phased-array NDT system. The concept of multi-parameter a, where the response of the NDT system is dependent on more than just one parameter, is introduced. The weakness of use of the peak signal response in the analysis is demonstrated and integration of the amplitudes in the C-scan is proposed as an alternative. The calculation of the volume POD, when the part is inspected with more configurations, is also presented. The reliability analysis is supported by the ultrasonic simulation based on the point source synthesis method

  15. Test particle acceleration in torsional spine magnetic reconnection

    Science.gov (United States)

    Hosseinpour, M.

    2014-10-01

    Three-dimensional (3D) magnetic reconnection is taking place commonly in astrophysical and space plasmas, especially in solar flares which are rich sources of highly energetic particles. One of the proposed mechanisms for steady-state 3D magnetic reconnection is "torsional spine reconnection". By using the magnetic and electric fields for "torsional spine reconnection", we numerically investigate the features of test particle acceleration with input parameters for the solar corona. We show that efficient acceleration of a relativistic proton is possible near the null point where it can gain up to 100 MeV of kinetic energy within a few milliseconds. However, varying the injection position results in different scenarios for proton acceleration. A proton is most efficiently accelerated when it is injected at the point where the magnetic field lines change their curvature in the fan plane. Moreover, a proton injected far away from the null point cannot be accelerated and, even in some cases, it is trapped in the magnetic field. In addition, adopting either spatially uniform or non-uniform localized plasma resistivity does not much influence the features of trajectory.

  16. Reliability and validity of a novel intermittent peak running speed test for Australian football.

    Science.gov (United States)

    Mooney, Mitchell G; Hunter, Jayden R; O'Brien, Brendan J; Berry, Jason T; Young, Warren B

    2011-04-01

    Australian football requires frequent intermittent sprinting close to peak running speed. However, tests assessing the capability to maintain intermittent peak running speed are not reported in scientific literature. Therefore, our objective is to report the reliability and validity of a novel intermittent peak running speed test. The intermittent peak running speed test required footballers to perform 10 repetitions on 25-second intervals. Each repetition required 15-m jogging, 20-m acceleration to peak speed, 10 m to sustain peak speed, 20-m deceleration, and finally a 15-m jog. Intermittent peak running speed was determined by portable global positioning system. To assess reliability, 26 footballers performed the intermittent peak running speed test on 2 occasions 3-5 days apart. Our results revealed that average peak speed had a coefficient of variation of 2.2% and an intraclass correlation of 0.91. To assess construct validity, average peak speed was compared between elite, sub-elite, and regional footballers. The average peak speed of the elite footballers (28.6 ± 1.7 km · h(-1)) was higher than that of the sub-elite (27.4 ± 1.7 km · h(-1)) and regional (27 ± 1.9 km · h(-1)) competitors (p intermittent peak running speed test possesses acceptable reliability and distinguishes between elite and sub-elite footballers.

  17. Accelerated cycle-life testing of small sealed lead/acid batteries

    Science.gov (United States)

    Kim, I.; Oh, S. H.; Kang, H. Y.

    An attempt has been made to devise methods for reducing the cycle-testing time of long-life sealed lead/acid batteries. In order for the accelerated test results to equate to the actual field operations, it is assumed that the failure modes under both normal and accelerated conditions must be the same. As a first step in the search for a reliable accelerated test, observations of the battery ageing process have been made under different daily duty cycles, viz., 1 (normal), 8 and 16 cycles/day at ambient temperature and 80% depth-of-discharge. It has been found that the main cause of failure is different for a given duty cycle. This complicates the task of applying accelerated test results to field operations. For the 8 cycles/day schedule, the main cause of failure is degradation of the positive active material. Positive grid corrosion is the main factor in the 16 cycles/day case. Under normal conditions, both grid corrosion and PbO 2 degradation appear to be equally significant.

  18. Lifetime Prediction for Degradation of Solar Mirrors using Step-Stress Accelerated Testing (Presentation)

    Energy Technology Data Exchange (ETDEWEB)

    Lee, J.; Elmore, R.; Kennedy, C.; Gray, M.; Jones, W.

    2011-09-01

    This research is to illustrate the use of statistical inference techniques in order to quantify the uncertainty surrounding reliability estimates in a step-stress accelerated degradation testing (SSADT) scenario. SSADT can be used when a researcher is faced with a resource-constrained environment, e.g., limits on chamber time or on the number of units to test. We apply the SSADT methodology to a degradation experiment involving concentrated solar power (CSP) mirrors and compare the results to a more traditional multiple accelerated testing paradigm. Specifically, our work includes: (1) designing a durability testing plan for solar mirrors (3M's new improved silvered acrylic "Solar Reflector Film (SFM) 1100") through the ultra-accelerated weathering system (UAWS), (2) defining degradation paths of optical performance based on the SSADT model which is accelerated by high UV-radiant exposure, and (3) developing service lifetime prediction models for solar mirrors using advanced statistical inference. We use the method of least squares to estimate the model parameters and this serves as the basis for the statistical inference in SSADT. Several quantities of interest can be estimated from this procedure, e.g., mean-time-to-failure (MTTF) and warranty time. The methods allow for the estimation of quantities that may be of interest to the domain scientists.

  19. Gearbox Reliability Collaborative Phase 3 Gearbox 3 Test Report

    Energy Technology Data Exchange (ETDEWEB)

    Keller, Jonathan [National Renewable Energy Lab. (NREL), Golden, CO (United States); Wallen, Robb [National Renewable Energy Lab. (NREL), Golden, CO (United States)

    2017-02-24

    Many gearboxes in wind turbines do not achieve their expected design life; they do, however, commonly meet or exceed the design criteria specified in current standards in the gear, bearing, and wind turbine industry as well as third-party certification criteria. The cost of gearbox replacements and rebuilds, as well as the downtime associated with these failures, increases the cost of wind energy. In 2007, the U.S. Department of Energy established the National Renewable Energy Laboratory (NREL) Gearbox Reliability Collaborative (GRC). Its goals are to understand the root causes of premature gearbox failures and to improve their reliability. The GRC is examining a hypothesis that the gap between design-estimated and actual wind turbine gearbox reliability is caused by underestimation of loads, inaccurate design tools, the absence of critical elements in the design process, or insufficient testing. This report describes the recently completed tests of GRC Gearbox 3 in the National Wind Technology Center dynamometer and documents any modifications to the original test plan. In this manner, it serves as a guide for interpreting the publicly released data sets with brief analyses to illustrate the data. The primary test objective was to measure the planetary load-sharing characteristics in the same conditions as the original GRC gearbox design. If the measured load-sharing characteristics are close to the design model, the projected improvement in planetary section fatigue life and the efficacy of preloaded TRBs in mitigating the planetary bearing fatigue failure mode will have been demonstrated. Detailed analysis of that test objective will be presented in subsequent publications.

  20. Reliability and validity testing of an archery chronometer.

    Science.gov (United States)

    Ertan, Hayri; Kentel, Behzat B; Tümer, S Turgut; Korkusuz, Feza

    2005-06-01

    Keeping the arrow velocity constant during consecutive shots and responding to "clicker's fall "are considered to be an important feature of archery performance. A specially designed device called an archery chronometer was developed to measure the reaction time of an archer to clicker's fall, arrow velocity, and external factors that may affect arrow velocity. The purposes of this study were to test (1) the validity of Clicker Reaction Time (CRT) measurer, and (2) the reliability of CRT in accordance with the Flying Time (FT)/Average Speed (AS), temperature (TEMP), wind speed (WS) and wind direction (WD) measurements. 20 elite archers participated in this study. The Reaction Time (RT), which was derived from EMG values and CRT from the archery chronometer were correlated to test the validity of the CRT measurer. The test re-test method was applied to test the reliability of archery chronometer. CRT scores were related with RT scores (r = .787, p archery chronometer was valid in terms of predicting reaction time. The device was found to be reliable in measuring CRT, AS, FT, WS, WD, and TEMP. It was concluded that archery chronometer could be used for technical evaluation and enhancing ones shooting technique in archery. Key PointsClicker Reaction Time could be used as a predictor of Reaction Time in archery.Archery Chronometer can be used for evaluating the archers' shooting technique and the bow-arrow interaction.Archery Chronometer can also be used as an indicator for ballistic flight of an arrow.Archery Chronometer can be used by the coaches and the archers to evaluate and enhance shooting technique in the natural settings of their training environment.

  1. Chemical complexity of odors increases reliability of olfactory threshold testing.

    Science.gov (United States)

    Oleszkiewicz, Anna; Pellegrino, Robert; Pusch, Katharina; Margot, Celine; Hummel, Thomas

    2017-01-10

    Assessment of odor thresholds is a widely recognized method of measuring olfactory abilities in humans. To date no attempts have been made to assess whether chemical complexity of odors used can produce more reliable results. To this end, we performed two studies of repeated measures design with 121 healthy volunteers (age 19-62 years). In Study 1, we compared thresholds obtained from tests based on one odor presented in a pen-like odor dispensing device with three odors and six odors mixtures presented in glass containers. In study 2 we compared stimuli of one and three odors, both presented in glass containers. In both studies measurements were performed twice, separated by at least three days. Results indicate that the multiple odor mixtures produced more reliable threshold scores, as compared to thresholds based on a single substance.

  2. On the reliability of microvariability tests in quasars

    CERN Document Server

    de Diego, José A

    2014-01-01

    Microvariations probe the physics and internal structure of quasars. Unpredictability and small flux variations make this phenomenon elusive and difficult to detect. Variance based probes such as the C and F tests, or a combination of both, are popular methods to compare the light-curves of the quasar and a comparison star. Recently, detection claims in some studies depend on the agreement of the results of the C and F tests, or of two instances of the F-test, in rejecting the non-variation null hypothesis. However, the C-test is a non-reliable statistical procedure, the F-test is not robust, and the combination of tests with concurrent results is anything but a straightforward methodology. A priori Power Analysis calculations and post hoc analysis of Monte-Carlo simulations show excellent agreement for the Analysis of Variance test to detect microvariations, as well as the limitations of the F-test. Additionally, combined tests yield correlated probabilities that make the assessment of statistical significan...

  3. Mechanical Stability Study for Integrable Optics Test Accelerator at Fermilab

    Energy Technology Data Exchange (ETDEWEB)

    McGee, Mike [Fermilab; Andrews, Richard [Fermilab; Carlson, Kermit [Fermilab; Leibfritz, Jerry [Fermilab; Nobrega, Lucy [Fermilab; Valishev, Alexander [Fermilab

    2016-07-01

    The Integrable Optics Test Accelerator (IOTA) is proposed for operation at Fermilab. The goal of IOTA is to create practical nonlinear accelerator focusing systems with a large frequency spread and stable particle motion. The IOTA is a 40 m circumference, 150 MeV (e-), 2.5 MeV (p⁺) diagnostic test ring. A heavy low frequency steel floor girder is proposed as the primary tier for IOTA device component support. Two design lengths; (8) 4 m and (2) 2.8 m long girders with identical cross section completely encompass the ring. This study focuses on the 4 m length girder and the development of a working prototype. Hydrostatic Level Sensor (HLS), temperature, metrology and fast motion measurements characterize the anticipated mechanical stability of the IOTA ring.

  4. European accelerator facilities for single event effects testing

    Energy Technology Data Exchange (ETDEWEB)

    Adams, L.; Nickson, R.; Harboe-Sorensen, R. [ESA-ESTEC, Noordwijk (Netherlands); Hajdas, W.; Berger, G.

    1997-03-01

    Single event effects are an important hazard to spacecraft and payloads. The advances in component technology, with shrinking dimensions and increasing complexity will give even more importance to single event effects in the future. The ground test facilities are complex and expensive and the complexities of installing a facility are compounded by the requirement that maximum control is to be exercised by users largely unfamiliar with accelerator technology. The PIF and the HIF are the result of experience gained in the field of single event effects testing and represent a unique collaboration between space technology and accelerator experts. Both facilities form an essential part of the European infrastructure supporting space projects. (J.P.N.)

  5. Mechanical stability study for Integrable Optics Test Accelerator at Fermilab

    CERN Document Server

    McGee, M W; Carlson, K; Leibfritz, J; Nobrega, L; Valishev, A

    2016-01-01

    The Integrable Optics Test Accelerator (IOTA) is proposed for operation at Fermilab. The goal of IOTA is to create practical nonlinear accelerator focusing systems with a large frequency spread and stable particle motion. The IOTA is a 40 m circumference, 150 MeV (e-), 2.5 MeV (p+) diagnostic test ring. A heavy low frequency steel floor girder is proposed as the primary tier for IOTA device component support. Two design lengths; (8) 3.96 m and (2) 3.1 m long girders with identical cross section completely encompass the ring. This study focuses on the 3.96 m length girder and the development of a working prototype. Hydrostatic Level Sensor (HLS), temperature, metrology and fast motion measurements characterize the anticipated mechanical stability of the IOTA ring.

  6. Timed Up and Go Test: A Reliable and Valid Test in Patients With Chronic Heart Failure.

    Science.gov (United States)

    Hwang, Rita; Morris, Norman R; Mandrusiak, Allison; Mudge, Alison; Suna, Jessica; Adsett, Julie; Russell, Trevor

    2016-08-01

    The timed up and go test (TUGT) is a short-duration functional test frequently used in rehabilitation settings as a measure of balance and mobility. Reliability and validity for patients with chronic heart failure (CHF) has yet to be determined. This prospective cohort study aimed to determine test-retest reliability of the TUGT in patients with CHF, relationships between the TUGT and other variables, including functional tests, and predictors of the TUGT. This was a secondary analysis of data collected in a multicenter randomized controlled trial of exercise training in recently hospitalized patients with heart failure (EJECTION-HF). The TUGT was conducted twice at baseline to determine reliability. Assessments were compared with 6-minute walk distance (6MWD), 10-m walk test time, and other clinical variables. Intraclass correlation coefficient (ICC) was used to determine test-retest reliability and correlations for relationships with other variables. A multiple regression was used to identify predictors of the TUGT. In 278 participants (mean age 62 years), the TUGT demonstrated excellent within-day test-retest reliability (ICC 0.93). A shorter (better) TUGT time was associated with longer 6MWD (r = -0.81; P time (rs = 0.80; P < .001). Best predictors of the TUGT were 6MWD and age, which accounted for 66% of the variance. The TUGT appears to be a reliable and valid functional measurement in patients with CHF. Crown Copyright © 2015. Published by Elsevier Inc. All rights reserved.

  7. Accelerated Creep Testing of High Strength Aramid Webbing

    Science.gov (United States)

    Jones, Thomas C.; Doggett, William R.; Stnfield, Clarence E.; Valverde, Omar

    2012-01-01

    A series of preliminary accelerated creep tests were performed on four variants of 12K and 24K lbf rated Vectran webbing to help develop an accelerated creep test methodology and analysis capability for high strength aramid webbings. The variants included pristine, aged, folded and stitched samples. This class of webbings is used in the restraint layer of habitable, inflatable space structures, for which the lifetime properties are currently not well characterized. The Stepped Isothermal Method was used to accelerate the creep life of the webbings and a novel stereo photogrammetry system was used to measure the full-field strains. A custom MATLAB code is described, and used to reduce the strain data to produce master creep curves for the test samples. Initial results show good correlation between replicates; however, it is clear that a larger number of samples are needed to build confidence in the consistency of the results. It is noted that local fiber breaks affect the creep response in a similar manner to increasing the load, thus raising the creep rate and reducing the time to creep failure. The stitched webbings produced the highest variance between replicates, due to the combination of higher local stresses and thread-on-fiber damage. Large variability in the strength of the webbings is also shown to have an impact on the range of predicted creep life.

  8. Test-Retest Reliability of an Automated Infrared-Assisted Trunk Accelerometer-Based Gait Analysis System

    Directory of Open Access Journals (Sweden)

    Chia-Yu Hsu

    2016-07-01

    Full Text Available The aim of this study was to determine the test-retest reliability of an automated infrared-assisted, trunk accelerometer-based gait analysis system for measuring gait parameters of healthy subjects in a hospital. Thirty-five participants (28 of them females; age range, 23–79 years performed a 5-m walk twice using an accelerometer-based gait analysis system with infrared assist. Measurements of spatiotemporal gait parameters (walking speed, step length, and cadence and trunk control (gait symmetry, gait regularity, acceleration root mean square (RMS, and acceleration root mean square ratio (RMSR were recorded in two separate walking tests conducted 1 week apart. Relative and absolute test-retest reliability was determined by calculating the intra-class correlation coefficient (ICC3,1 and smallest detectable difference (SDD, respectively. The test-retest reliability was excellent for walking speed (ICC = 0.87, 95% confidence interval = 0.74–0.93, SDD = 13.4%, step length (ICC = 0.81, 95% confidence interval = 0.63–0.91, SDD = 12.2%, cadence (ICC = 0.81, 95% confidence interval = 0.63–0.91, SDD = 10.8%, and trunk control (step and stride regularity in anterior-posterior direction, acceleration RMS and acceleration RMSR in medial-lateral direction, and acceleration RMS and stride regularity in vertical direction. An automated infrared-assisted, trunk accelerometer-based gait analysis system is a reliable tool for measuring gait parameters in the hospital environment.

  9. Beam Profile Measurement of 300 kV Ion Source Test Stand for 1 MV Electrostatic Accelerator

    Energy Technology Data Exchange (ETDEWEB)

    Park, Sae-Hoon; Kim, Yu-Seok [Dongguk University, Gyeonju (Korea, Republic of); Kim, Dae-Il; Kwon, Hyeok-Jung; Cho, Yong-Sub [Korea Multipurpose Accelerator Complex, Gyeongju (Korea, Republic of)

    2015-10-15

    In this paper, RF ion source, test stand of the ion source and its test results are presented. Beam profile was measured at the downstream from the accelerating tube and at the beam dump by using BPM and wire scanner. The RF ion source of the test stand is verified by measuring the total beam current with a faraday cup in the chamber. The KOMAC (KOrea Multi-purpose Accelerator Complex) has been developing a 300 kV ion source test stand for a 1 MV electrostatic accelerator. An ion source and accelerating tube will be installed in a high pressure vessel. The ion source in a high pressure vessel requires high reliability. To confirm the stable operation of the ion source, a test stand was proposed and developed. The ion source will be tested at the test stand to verify its long-term operation conditions. The test stand consists of a 300 kV high voltage terminal, a battery for the ion source power, a 60 Hz inverter, a 200 MHz RF power, a 5 kV extraction power supply, a 300 kV accelerating tube, and a vacuum system. The beam profile monitor was installed at the downstream from the accelerating tube. Wire scanner and faraday-cup was installed at the end of the chamber.

  10. Test re-test reliability and construct validity of the star-track test of manual dexterity

    DEFF Research Database (Denmark)

    Kildebro, Niels; Amirian, Ilda; Gögenur, Ismail

    2015-01-01

    integrated scores ranging from 47-59% difference in mean. Conclusion. The star track test of manual dexterity had a strong test re-test reliability, and was able to discriminate between a subject's normal manual dexterity and dexterity after exposure to fatigue and/or stress.......Objectives. We wished to determine test re-test reliability and construct validity of the star-track test of manual dexterity. Design. Test re-test reliability was examined in a controlled study. Construct validity was tested in a blinded randomized crossover study. Setting. The study was performed...... at a university hospital in Denmark. Participants. A total of 11 subjects for test re-test and 20 subjects for the construct validity study were included. All subjects were healthy volunteers. Intervention. The test re-test trial had two measurements with 2 days pause in between. The interventions...

  11. FY 88 laser transport experiments on ATA (Advanced Test Accelerator)

    Energy Technology Data Exchange (ETDEWEB)

    Chambers, F.W.; Boyd, J.K.; Caporaso, G.J.; Chong, Y.P.; Fawley, W.M.; Hildum, J.S.; Lee, P.; Orzechowski, T.J.; Prono, D.S.; Smith, A.C.

    1988-11-01

    An experiment was conducted at the Advanced Test Accelerator (ATA) in the spring/summer of 1988 to study the transport of the ''laser guided'' electron beam through the accelerator and beyond. The electron beam was guided from the /approximately/3.75 MeV point through the accelerator on an ion channel created by firing a KrF laser (248 nm, P approx.100--400 mJ) into a benzene filled (p approx..1 ..mu..) beamline. Beam transport was documented at several locations with a variety of diagnostics for various beam parameters; channel, gas, and laser parameters; and for various machine configurations. The focus of this experiment was to document, understand, and then alter (remove) the time variation in the observed accelerated beam parameters. The temporal variation of the beam manifests itself in several ways as has been documented. Beam radius versus time, R(t), from both bow probe and optical data shows the beam radius expanding by factors of up to several over the 40 ns of beam pulse. When the beam is threaded through any device with a limited acceptance the radius variation is parlayed into a current variation, I(t). This has been documented for transport through the fusible link, rise time sharpener, slits, bends, emittance selectors, and during free expansion. The beam temporal variation in time may be viewed as radius increase or blowup, brightness degradation, or emittance increase. The observations of blowup predate the introduction of the collimator. The observations prior to this experiment were made in the post accelerator transport sections. 9 refs., 4 figs.

  12. Reliability and Validity of the Inline Skating Skill Test

    Directory of Open Access Journals (Sweden)

    Ivan Radman, Lana Ruzic, Viktoria Padovan, Vjekoslav Cigrovski, Hrvoje Podnar

    2016-09-01

    Full Text Available This study aimed to examine the reliability and validity of the inline skating skill test. Based on previous skating experience forty-two skaters (26 female and 16 male were randomized into two groups (competitive level vs. recreational level. They performed the test four times, with a recovery time of 45 minutes between sessions. Prior to testing, the participants rated their skating skill using a scale from 1 to 10. The protocol included performance time measurement through a course, combining different skating techniques. Trivial changes in performance time between the repeated sessions were determined in both competitive females/males and recreational females/males (-1.7% [95% CI: -5.8–2.6%] – 2.2% [95% CI: 0.0–4.5%]. In all four subgroups, the skill test had a low mean within-individual variation (1.6% [95% CI: 1.2–2.4%] – 2.7% [95% CI: 2.1–4.0%] and high mean inter-session correlation (ICC = 0.97 [95% CI: 0.92–0.99] – 0.99 [95% CI: 0.98–1.00]. The comparison of detected typical errors and smallest worthwhile changes (calculated as standard deviations × 0.2 revealed that the skill test was able to track changes in skaters’ performances. Competitive-level skaters needed shorter time (24.4–26.4%, all p < 0.01 to complete the test in comparison to recreational-level skaters. Moreover, moderate correlation (ρ = 0.80–0.82; all p < 0.01 was observed between the participant’s self-rating and achieved performance times. In conclusion, the proposed test is a reliable and valid method to evaluate inline skating skills in amateur competitive and recreational level skaters. Further studies are needed to evaluate the reproducibility of this skill test in different populations including elite inline skaters.

  13. Vibrational measurement for commissioning SRF Accelerator Test Facility at Fermilab

    CERN Document Server

    McGee, M W; Martinez, A; Pischalnikov, Y; Schappert, W

    2012-01-01

    The commissioning of two cryomodule components is underway at Fermilab's Superconducting Radio Frequency (SRF) Accelerator Test Facility. The research at this facility supports the next generation high intensity linear accelerators such as the International Linear Collider (ILC), a new high intensity injector (Project X) and other future machines. These components, Cryomodule #1 (CM1) and Capture Cavity II (CC2), which contain 1.3 GHz cavities are connected in series in the beamline and through cryogenic plumbing. Studies regarding characterization of ground motion, technical and cultural noise continue. Mechanical transfer functions between the foundation and critical beamline components have been measured and overall system displacement characterized. Baseline motion measurements given initial operation of cryogenic, vacuum systems and other utilities are considered.

  14. Vibrational measurement for commissioning SRF Accelerator Test Facility at Fermilab

    Energy Technology Data Exchange (ETDEWEB)

    McGee, M.W.; Leibfritz, J.; Martinez, A.; Pischalnikov, Y.; Schappert, W.; /Fermilab

    2011-03-01

    The commissioning of two cryomodule components is underway at Fermilab's Superconducting Radio Frequency (SRF) Accelerator Test Facility. The research at this facility supports the next generation high intensity linear accelerators such as the International Linear Collider (ILC), a new high intensity injector (Project X) and other future machines. These components, Cryomodule No.1 (CM1) and Capture Cavity II (CC2), which contain 1.3 GHz cavities are connected in series in the beamline and through cryogenic plumbing. Studies regarding characterization of ground motion, technical and cultural noise continue. Mechanical transfer functions between the foundation and critical beamline components have been measured and overall system displacement characterized. Baseline motion measurements given initial operation of cryogenic, vacuum systems and other utilities are considered.

  15. The reliability of specific sacro-occipital technique diagnostic tests.

    Science.gov (United States)

    Leboeuf, C

    1991-01-01

    Four interexaminer and one intraexaminer agreement studies were performed on specific diagnostic tests commonly employed within sacro-occipital technique (SOT). Ten of the tests were evaluated in more than one interexaminer study. Of these, only one test (bilateral supine leg raise with cervical compaction) had at least fair reliability more than once. Six of these 10 tests obtained poor agreement in more than one study. One examiner out of two had a number of excellent and fair intraexaminer values, whereas the other examiner generally had poor results. There may have been some treatment effect as a comparison of the combined intraexaminer diagnosis for two observers after no treatment and after treatment showed that the repeatability diminished from Kappa of 0.36 in untreated cases (which were expected to have high agreement of before and after treatment findings) to a Kappa of 0.27 for those subjects having received treatment (which were expected to have low agreement of before and after treatment findings). It appears unlikely that SOT tests can be reproduced to a sufficiently high degree to constitute useful clinical procedures.

  16. GNSS Reliability Testing in Signal-Degraded Scenario

    Directory of Open Access Journals (Sweden)

    A. Angrisano

    2013-01-01

    Full Text Available Multiconstellation satellite navigation is critical in signal-degraded environments where signals are strongly corrupted. In this case, the use of a single GNSS system does not guarantee an accurate and continuous positioning. A possible approach to solve this problem is the use of multiconstellation receivers that provide additional measurements and allows robust reliability testing; in this work, a GPS/GLONASS combination is considered. In urban scenario, a modification of the classical RAIM technique is necessary taking into account frequent multiple blunders. The FDE schemes analysed are the “Observation Subset Testing,” “Forward-Backward Method,” and “Danish Method”; they are obtained by combining different basic statistical tests. The considered FDE methods are modified to optimize their behaviour in urban scenario. Specifically a preliminary check is implemented to screen out bad geometries. Moreover, a large blunder could cause multiple test failures; hence, a separability index is implemented to avoid the incorrect exclusion of blunder-free measurements. Testing the RAIM algorithms of GPS/GLONASS combination to verify the benefits relative to GPS only case is a main target of this work too. The performance of these methods is compared in terms of RMS and maximum error for the horizontal and vertical components of position and velocity.

  17. Particle accelerators and nuclear energy: the challenge of reliability; Acceleradores de particulas y energia nuclear: el desafio de la fiabilidad

    Energy Technology Data Exchange (ETDEWEB)

    Brucker, R.; Fernandez Ramos, P.

    2011-07-01

    High energy particle accelerators, that used to serve a purpose only in fundamental research, will soon be used in industrial applications of nuclear energy. In this context, they will be submitted to unprecedented (as far as such machines are concerned) reliability requirements. In order to meet them, reliability studies need to be carried out. This article describes the experience gained by Empresarios Agrupados in that field (with the Eurotrans and Ifmif projects) and presents their future activities in the framework of the Myrrha project, that is aimed at building the first ADS reactor in the world. (Author)

  18. Optimum Accelerated Degradation Tests for the Gamma Degradation Process Case under the Constraint of Total Cost

    Directory of Open Access Journals (Sweden)

    Heonsang Lim

    2015-04-01

    Full Text Available An accelerated degradation test (ADT is regarded as an effective alternative to an accelerated life test in the sense that an ADT can provide more accurate information on product reliability, even when few or no failures may be expected before the end of a practical test period. In this paper, statistical methods for optimal designing ADT plans are developed assuming that the degradation characteristic follows a gamma process (GP. The GP-based approach has an advantage that it can deal with more frequently encountered situations in which the degradation should always be nonnegative and strictly increasing over time. The optimal ADT plan is developed under the total experimental cost constraint by determining the optimal settings of variables such as the number of measurements, the measurement times, the test stress levels and the number of units allocated to each stress level such that the asymptotic variance of the maximum likelihood estimator of the q-th quantile of the lifetime distribution at the use condition is minimized. In addition, compromise plans are developed to provide means to check the adequacy of the assumed acceleration model. Finally, sensitivity analysis procedures for assessing the effects of the uncertainties in the pre-estimates of unknown parameters are illustrated with an example.

  19. Improved Accelerated Stress Tests Based on Fuel Cell Vehicle Data

    Energy Technology Data Exchange (ETDEWEB)

    Patterson, Timothy [Research Engineer; Motupally, Sathya [Research Engineer

    2012-06-01

    UTC will led a top-tier team of industry and national laboratory participants to update and improve DOE’s Accelerated Stress Tests (AST’s) for hydrogen fuel cells. This in-depth investigation will focused on critical fuel cell components (e.g. membrane electrode assemblies - MEA) whose durability represented barriers for widespread commercialization of hydrogen fuel cell technology. UTC had access to MEA materials that had accrued significant load time under real-world conditions in PureMotion® 120 power plant used in transit buses. These materials are referred to as end-of-life (EOL) components in the rest of this document. Advanced characterization techniques were used to evaluate degradation mode progress using these critical cell components extracted from both bus power plants and corresponding materials tested using the DOE AST’s. These techniques were applied to samples at beginning-of-life (BOL) to serve as a baseline. These comparisons advised the progress of the various failure modes that these critical components were subjected to, such as membrane degradation, catalyst support corrosion, platinum group metal dissolution, and others. Gaps in the existing ASTs predicted the degradation observed in the field in terms of these modes were outlined. Using the gaps, new AST’s were recommended and tested to better reflect the degradation modes seen in field operation. Also, BOL components were degraded in a test vehicle at UTC designed to accelerate the bus field operation.

  20. Reliability and validity of the maximal anaerobic running test.

    Science.gov (United States)

    Nummela, A; Alberts, M; Rijntjes, R P; Luhtanen, P; Rusko, H

    1996-07-01

    Physically active men (n = 13) twice performed the Maximal Anaerobic Running Test (MART) on a treadmill and once the Wingate Anaerobic Test (WAnT) on a cycle ergometer. The MART consisted of n 20-s runs with 100-s recovery between the runs. The speed of the first run was 14.6 km.h-1 and the inclination 4 degrees. Thereafter, the speed was increased by 1.37 km.h-1 every run until exhaustion. During all tests oxygen uptake was measured breath-by-breath and blood samples were taken from the fingertip 40s after each run to determine the lactate concentration (BLa). Power at submaximal BLa levels and maximal power (P5mM, P10mM and Pmax, respectively) were calculated and P was expressed as the oxygen demand of running according to the American College of Sports Medicine equation. In the MART the Pmax was 108 ml.kg-1.min-1 and peak BLa was 15.6 mM. The reliability for the power indices in the MART were as follows: r = 0.92 (p cycle ergometer test measure slightly different qualities.

  1. Reliability Tests of the LHC Beam Loss Monitoring FPGA Firmware

    CERN Document Server

    Hajdu, C F; Dehning, B; Jackson, S

    2010-01-01

    The LHC Beam Loss Monitoring (BLM) system is one of the most complex instrumentation systems deployed in the LHC. In addition to protecting the collider, the system also needs to provide a means of diagnosing machine faults and deliver a feedback of losses to the control room as well as to several systems for their setup and analysis. It has to transmit and process signals from almost 4’000 monitors, and has nearly 3 million configurable parameters. In a system of such complexity, firmware reliability is a critical issue. The integrity of the signal chain of the LHC BLM system and its ability to correctly detect unwanted scenarios and thus provide the required protection level must be ensured. In order to analyze the reliability and functionality, an advanced verification environment has been developed to evaluate the performance and response of the FPGA-based data analysis firmware. This paper will report on the numerous tests that have been performed and on how the results are used to quantify the reliabi...

  2. Reliability of brain volume measurements: a test-retest dataset.

    Science.gov (United States)

    Maclaren, Julian; Han, Zhaoying; Vos, Sjoerd B; Fischbein, Nancy; Bammer, Roland

    2014-01-01

    Evaluation of neurodegenerative disease progression may be assisted by quantification of the volume of structures in the human brain using magnetic resonance imaging (MRI). Automated segmentation software has improved the feasibility of this approach, but often the reliability of measurements is uncertain. We have established a unique dataset to assess the repeatability of brain segmentation and analysis methods. We acquired 120 T1-weighted volumes from 3 subjects (40 volumes/subject) in 20 sessions spanning 31 days, using the protocol recommended by the Alzheimer's Disease Neuroimaging Initiative (ADNI). Each subject was scanned twice within each session, with repositioning between the two scans, allowing determination of test-retest reliability both within a single session (intra-session) and from day to day (inter-session). To demonstrate the application of the dataset, all 3D volumes were processed using FreeSurfer v5.1. The coefficient of variation of volumetric measurements was between 1.6% (caudate) and 6.1% (thalamus). Inter-session variability exceeded intra-session variability for lateral ventricle volume (P<0.0001), indicating that ventricle volume in the subjects varied between days.

  3. Acceleration of dormant storage effects to address the reliability of silicon surface micromachined Micro-Electro-Mechanical Systems (MEMS).

    Energy Technology Data Exchange (ETDEWEB)

    Cox, James V.; Candelaria, Sam A.; Dugger, Michael Thomas; Duesterhaus, Michelle Ann; Tanner, Danelle Mary; Timpe, Shannon J.; Ohlhausen, James Anthony; Skousen, Troy J.; Jenkins, Mark W.; Jokiel, Bernhard, Jr.; Walraven, Jeremy Allen; Parson, Ted Blair

    2006-06-01

    Qualification of microsystems for weapon applications is critically dependent on our ability to build confidence in their performance, by predicting the evolution of their behavior over time in the stockpile. The objective of this work was to accelerate aging mechanisms operative in surface micromachined silicon microelectromechanical systems (MEMS) with contacting surfaces that are stored for many years prior to use, to determine the effects of aging on reliability, and relate those effects to changes in the behavior of interfaces. Hence the main focus was on 'dormant' storage effects on the reliability of devices having mechanical contacts, the first time they must move. A large number ({approx}1000) of modules containing prototype devices and diagnostic structures were packaged using the best available processes for simple electromechanical devices. The packaging processes evolved during the project to better protect surfaces from exposure to contaminants and water vapor. Packages were subjected to accelerated aging and stress tests to explore dormancy and operational environment effects on reliability and performance. Functional tests and quantitative measurements of adhesion and friction demonstrated that the main failure mechanism during dormant storage is change in adhesion and friction, precipitated by loss of the fluorinated monolayer applied after fabrication. The data indicate that damage to the monolayer can occur at water vapor concentrations as low as 500 ppm inside the package. The most common type of failure was attributed to surfaces that were in direct contact during aging. The application of quantitative methods for monolayer lubricant analysis showed that even though the coverage of vapor-deposited monolayers is generally very uniform, even on hidden surfaces, locations of intimate contact can be significantly depleted in initial concentration of lubricating molecules. These areas represent defects in the film prone to adsorption of

  4. Reliability of the Test of Wheeled Mobility (TOWM) and the Short Wheelie Test

    NARCIS (Netherlands)

    Fliess-Douer, Osnat; Van der Woude, Lucas H. V.; Vanlandewijck, Yves C.

    2013-01-01

    Objective: To assess the reliability of the Test of Wheeled Mobility (TOWM) and the Wheelie test. Design: Cohort study. Setting: Gymnasium. Participants: Manual wheelchair users (N=30, age 23-53y) with a spinal cord injury. Intervention: Participants performed the 30 skills of the TOWM and the 8 ski

  5. Forward lunge as a functional performance test in ACL deficient subjects: test-retest reliability

    DEFF Research Database (Denmark)

    Alkjaer, Tine; Henriksen, Marius; Dyhre-Poulsen, Poul

    2009-01-01

    The forward lunge movement may be used as a functional performance test of anterior cruciate ligament (ACL) deficient and reconstructed subjects. The purposes were 1) to determine the test-retest reliability of a forward lunge in healthy subjects and 2) to determine the required numbers of repeti...

  6. Simulations and Vacuum Tests of a CLIC Accelerating Structure

    CERN Document Server

    Garion, C

    2011-01-01

    The Compact LInear Collider, under study, is based on room temperature high gradient structures. The vacuum specificities of these cavities are low conductance, large surface areas and a non-baked system. The main issue is to reach UHV conditions (typically 10-7 Pa) in a system where the residual vacuum is driven by water outgassing. A finite element model based on an analogy thermal/vacuum has been built to estimate the vacuum profile in an accelerating structure. Vacuum tests are carried out in a dedicated set-up, the vacuum performances of different configurations are presented and compared with the predictions.

  7. Proton Injection into the Fermilab Integrable Optics Test Accelerator (IOTA)

    Energy Technology Data Exchange (ETDEWEB)

    Prebys, Eric [Fermilab; Antipov, Sergey [Chicago U.; Piekarz, Henryk [Fermilab; Valishev, A. [Fermilab

    2015-06-01

    The Integrable Optics Test Accelerator (IOTA) is an experimental synchrotron being built at Fermilab to test the concept of non-linear "integrable optics". These optics are based on a lattice including non-linear elements that satisfies particular conditions on the Hamiltonian. The resulting particle motion is predicted to be stable but without a unique tune. The system is therefore insensitive to resonant instabilities and can in principle store very intense beams, with space charge tune shifts larger than those which are possible in conventional linear synchrotrons. The ring will initially be tested with pencil electron beams, but this poster describes the ultimate plan to install a 2.5 MeV RFQ to inject protons, which will produce tune shifts on the order of unity. Technical details will be presented, as well as simulations of protons in the ring.

  8. Proton Injection into the Fermilab Integrable Optics Test Accelerator (IOTA)

    Energy Technology Data Exchange (ETDEWEB)

    Prebys, Eric [Fermilab; Antipov, Sergey [Chicago U.; Piekarz, Henryk [Fermilab; Valishev, A. [Fermilab

    2015-06-01

    The Integrable Optics Test Accelerator (IOTA) is an experimental synchrotron being built at Fermilab to test the concept of non-linear "integrable optics". These optics are based on a lattice including non-linear elements that satisfies particular conditions on the Hamiltonian. The resulting particle motion is predicted to be stable but without a unique tune. The system is therefore insensitive to resonant instabilities and can in principle store very intense beams, with space charge tune shifts larger than those which are possible in conventional linear synchrotrons. The ring will initially be tested with pencil electron beams, but this poster describes the ultimate plan to install a 2.5 MeV RFQ to inject protons, which will produce tune shifts on the order of unity. Technical details will be presented, as well as simulations of protons in the ring.

  9. Testing the Difference between Reliability Coefficients Alpha and Omega

    Science.gov (United States)

    Deng, Lifang; Chan, Wai

    2017-01-01

    Reliable measurements are key to social science research. Multiple measures of reliability of the total score have been developed, including coefficient alpha, coefficient omega, the greatest lower bound reliability, and others. Among these, the coefficient alpha has been most widely used, and it is reported in nearly every study involving the…

  10. Face Perception and Test Reliabilities in Congenital Prosopagnosia in Seven Tests.

    Science.gov (United States)

    Esins, Janina; Schultz, Johannes; Stemper, Claudia; Kennerknecht, Ingo; Bülthoff, Isabelle

    2016-01-01

    Congenital prosopagnosia, the innate impairment in recognizing faces, is a very heterogeneous disorder with different phenotypical manifestations. To investigate the nature of prosopagnosia in more detail, we tested 16 prosopagnosics and 21 controls with an extended test battery addressing various aspects of face recognition. Our results show that prosopagnosics exhibited significant impairments in several face recognition tasks: impaired holistic processing (they were tested amongst others with the Cambridge Face Memory Test (CFMT)) as well as reduced processing of configural information of faces. This test battery also revealed some new findings. While controls recognized moving faces better than static faces, prosopagnosics did not exhibit this effect. Furthermore, prosopagnosics had significantly impaired gender recognition-which is shown on a groupwise level for the first time in our study. There was no difference between groups in the automatic extraction of face identity information or in object recognition as tested with the Cambridge Car Memory Test. In addition, a methodological analysis of the tests revealed reduced reliability for holistic face processing tests in prosopagnosics. To our knowledge, this is the first study to show that prosopagnosics showed a significantly reduced reliability coefficient (Cronbach's alpha) in the CFMT compared to the controls. We suggest that compensatory strategies employed by the prosopagnosics might be the cause for the vast variety of response patterns revealed by the reduced test reliability. This finding raises the question whether classical face tests measure the same perceptual processes in controls and prosopagnosics.

  11. Face Perception and Test Reliabilities in Congenital Prosopagnosia in Seven Tests

    Directory of Open Access Journals (Sweden)

    Janina Esins

    2016-01-01

    Full Text Available Congenital prosopagnosia, the innate impairment in recognizing faces, is a very heterogeneous disorder with different phenotypical manifestations. To investigate the nature of prosopagnosia in more detail, we tested 16 prosopagnosics and 21 controls with an extended test battery addressing various aspects of face recognition. Our results show that prosopagnosics exhibited significant impairments in several face recognition tasks: impaired holistic processing (they were tested amongst others with the Cambridge Face Memory Test (CFMT as well as reduced processing of configural information of faces. This test battery also revealed some new findings. While controls recognized moving faces better than static faces, prosopagnosics did not exhibit this effect. Furthermore, prosopagnosics had significantly impaired gender recognition—which is shown on a groupwise level for the first time in our study. There was no difference between groups in the automatic extraction of face identity information or in object recognition as tested with the Cambridge Car Memory Test. In addition, a methodological analysis of the tests revealed reduced reliability for holistic face processing tests in prosopagnosics. To our knowledge, this is the first study to show that prosopagnosics showed a significantly reduced reliability coefficient (Cronbach’s alpha in the CFMT compared to the controls. We suggest that compensatory strategies employed by the prosopagnosics might be the cause for the vast variety of response patterns revealed by the reduced test reliability. This finding raises the question whether classical face tests measure the same perceptual processes in controls and prosopagnosics.

  12. GPUs, a new tool of acceleration in CFD: efficiency and reliability on smoothed particle hydrodynamics methods.

    Science.gov (United States)

    Crespo, Alejandro C; Dominguez, Jose M; Barreiro, Anxo; Gómez-Gesteira, Moncho; Rogers, Benedict D

    2011-01-01

    Smoothed Particle Hydrodynamics (SPH) is a numerical method commonly used in Computational Fluid Dynamics (CFD) to simulate complex free-surface flows. Simulations with this mesh-free particle method far exceed the capacity of a single processor. In this paper, as part of a dual-functioning code for either central processing units (CPUs) or Graphics Processor Units (GPUs), a parallelisation using GPUs is presented. The GPU parallelisation technique uses the Compute Unified Device Architecture (CUDA) of nVidia devices. Simulations with more than one million particles on a single GPU card exhibit speedups of up to two orders of magnitude over using a single-core CPU. It is demonstrated that the code achieves different speedups with different CUDA-enabled GPUs. The numerical behaviour of the SPH code is validated with a standard benchmark test case of dam break flow impacting on an obstacle where good agreement with the experimental results is observed. Both the achieved speed-ups and the quantitative agreement with experiments suggest that CUDA-based GPU programming can be used in SPH methods with efficiency and reliability.

  13. GPUs, a new tool of acceleration in CFD: efficiency and reliability on smoothed particle hydrodynamics methods.

    Directory of Open Access Journals (Sweden)

    Alejandro C Crespo

    Full Text Available Smoothed Particle Hydrodynamics (SPH is a numerical method commonly used in Computational Fluid Dynamics (CFD to simulate complex free-surface flows. Simulations with this mesh-free particle method far exceed the capacity of a single processor. In this paper, as part of a dual-functioning code for either central processing units (CPUs or Graphics Processor Units (GPUs, a parallelisation using GPUs is presented. The GPU parallelisation technique uses the Compute Unified Device Architecture (CUDA of nVidia devices. Simulations with more than one million particles on a single GPU card exhibit speedups of up to two orders of magnitude over using a single-core CPU. It is demonstrated that the code achieves different speedups with different CUDA-enabled GPUs. The numerical behaviour of the SPH code is validated with a standard benchmark test case of dam break flow impacting on an obstacle where good agreement with the experimental results is observed. Both the achieved speed-ups and the quantitative agreement with experiments suggest that CUDA-based GPU programming can be used in SPH methods with efficiency and reliability.

  14. Test-retest reliability of white matter structural brain networks: A multiband diffusion MRI study

    Directory of Open Access Journals (Sweden)

    Tengda eZhao

    2015-02-01

    Full Text Available The multiband EPI sequence has been developed for the human connectome project to accelerate MRI data acquisition. However, no study has yet investigated the test-retest (TRT reliability of the graph metrics of white matter (WM structural brain networks constructed from this new sequence. Here, we employed a multiband diffusion MRI (dMRI dataset with repeated scanning sessions and constructed both low- and high-resolution WM networks by volume- and surface-based parcellation methods. The reproducibility of network metrics and its dependence on type of construction procedures was assessed by the intra-class correlation coefficient (ICC. We observed conserved topological architecture of WM structural networks constructed from the multiband dMRI data as previous findings from conventional dMRI. For the global network properties, the first order metrics were more reliable than second order metrics. Between two parcellation methods, networks with volume-based parcellation showed better reliability than surface-based parcellation, especially for the global metrics. Between different resolutions, the high-resolution network exhibited higher TRT performance than the low-resolution in terms of the global metrics with a large effect size, whereas the low-resolution performs better in terms of local (region and connection properties with a relatively low effect size. Moreover, we identified that the association and primary cortices showed higher reproducibility than the paralimbic/limbic regions. The important hub regions and rich-club connections are more reliable than the non-hub regions and connections. Finally, we found WM networks from the multiband dMRI showed higher reproducibility compared with those from the conventional dMRI. Together, our results demonstrated the fair to good reliability of the WM structural brain networks from the multiband EPI sequence, suggesting its potential utility for exploring individual differences and for clinical

  15. Test-retest reliability of white matter structural brain networks: a multiband diffusion MRI study.

    Science.gov (United States)

    Zhao, Tengda; Duan, Fei; Liao, Xuhong; Dai, Zhengjia; Cao, Miao; He, Yong; Shu, Ni

    2015-01-01

    The multiband EPI sequence has been developed for the human connectome project to accelerate MRI data acquisition. However, no study has yet investigated the test-retest (TRT) reliability of the graph metrics of white matter (WM) structural brain networks constructed from this new sequence. Here, we employed a multiband diffusion MRI (dMRI) dataset with repeated scanning sessions and constructed both low- and high-resolution WM networks by volume- and surface-based parcellation methods. The reproducibility of network metrics and its dependence on type of construction procedures was assessed by the intra-class correlation coefficient (ICC). We observed conserved topological architecture of WM structural networks constructed from the multiband dMRI data as previous findings from conventional dMRI. For the global network properties, the first order metrics were more reliable than second order metrics. Between two parcellation methods, networks with volume-based parcellation showed better reliability than surface-based parcellation, especially for the global metrics. Between different resolutions, the high-resolution network exhibited higher TRT performance than the low-resolution in terms of the global metrics with a large effect size, whereas the low-resolution performs better in terms of local (region and connection) properties with a relatively low effect size. Moreover, we identified that the association and primary cortices showed higher reproducibility than the paralimbic/limbic regions. The important hub regions and rich-club connections are more reliable than the non-hub regions and connections. Finally, we found WM networks from the multiband dMRI showed higher reproducibility compared with those from the conventional dMRI. Together, our results demonstrated the fair to good reliability of the WM structural brain networks from the multiband EPI sequence, suggesting its potential utility for exploring individual differences and for clinical applications.

  16. Chapter 9: Reliability

    Energy Technology Data Exchange (ETDEWEB)

    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.

  17. Reliability of Diagnostic Tests for Helicobacter pylori Infection

    Directory of Open Access Journals (Sweden)

    S. Redéen

    2011-01-01

    Full Text Available Introduction. Helicobacter pylori (H. pylori infection is very common worldwide. A reliable diagnosis is crucial for patients with H. pylori-related diseases. At followup, it is important to confirm that eradication therapy has been successful. There is no established gold standard for the diagnosis of H. pylori infection. Material and Methods. A sample of 304 volunteers from the general population was screened for H. pylori infection with serology, 13C-urea breath test (UBT, rapid urease test (RUT on fresh biopsy, culture from biopsy, and histological examination. Culture was used as gold standard. Results. The sensitivity was 0.99 for serology, 0.90 for UBT, 0.90 for RUT, and 0.90 for histological examination. Corresponding specificities were 0.82, 0.99, 0.98, and 0.97, respectively. The accuracy was 0.86 for serology, 0.96 for UBT, 0.95 for RUT, 0.93 for culture, and 0.95 for histology. There was a strong correlation between the results of UBT and the histological scores of H. pylori colonisation as well as between the results of UBT and the scores of RUT. Conclusion. There were only minor differences in accuracy between the three invasive tests for H. pylori infection in this population. RUT may be recommended as the first choice since a result is obtained within hours. The accuracy of UBT was comparable to the invasive tests, and it is recommended for situations when endoscopy is not needed.

  18. Bayesian optimal design of step stress accelerated degradation testing

    Institute of Scientific and Technical Information of China (English)

    Xiaoyang Li; Mohammad Rezvanizaniani; Zhengzheng Ge; Mohamed Abuali; Jay Lee

    2015-01-01

    This study presents a Bayesian methodology for de-signing step stress accelerated degradation testing (SSADT) and its application to batteries. First, the simulation-based Bayesian de-sign framework for SSADT is presented. Then, by considering his-torical data, specific optimal objectives oriented Kul back–Leibler (KL) divergence is established. A numerical example is discussed to il ustrate the design approach. It is assumed that the degrada-tion model (or process) fol ows a drift Brownian motion;the accele-ration model fol ows Arrhenius equation; and the corresponding parameters fol ow normal and Gamma prior distributions. Using the Markov Chain Monte Carlo (MCMC) method and WinBUGS software, the comparison shows that KL divergence is better than quadratic loss for optimal criteria. Further, the effect of simulation outliers on the optimization plan is analyzed and the preferred sur-face fitting algorithm is chosen. At the end of the paper, a NASA lithium-ion battery dataset is used as historical information and the KL divergence oriented Bayesian design is compared with maxi-mum likelihood theory oriented local y optimal design. The results show that the proposed method can provide a much better testing plan for this engineering application.

  19. Using Uncertainty Analysis to Guide the Development of Accelerated Stress Tests (Presentation)

    Energy Technology Data Exchange (ETDEWEB)

    Kempe, M.

    2014-03-01

    Extrapolation of accelerated testing to the long-term results expected in the field has uncertainty associated with the acceleration factors and the range of possible stresses in the field. When multiple stresses (such as temperature and humidity) can be used to increase the acceleration, the uncertainty may be reduced according to which stress factors are used to accelerate the degradation.

  20. Repair mortars based on lime. Accelerated aging tests

    Directory of Open Access Journals (Sweden)

    Martínez-Ramírez, S.

    1995-06-01

    Full Text Available The behaviour under different accelerated aging tests (freeze/thaw and crystallization cycles of a new lime mortar with biocide properties destinated to monumental repair has been studied. New mortars (which have the biocide impregnated in a clay called sepiolite have a similar behaviour to lime mortars used as a reference. After the aging tests, the biocide properties of the mortars have been tried.

    Se ha estudiado el comportamiento frente a distintos ensayos de envejecimiento acelerado (ciclos de hielo/deshielo y cristalización de sales de un nuevo mortero de cal con propiedades biocidas, destinado a la reparación monumental. Se ha comprobado que los nuevos morteros (que llevan incorporado el biocida impregnado en una arcilla denominada sepiolita tienen un comportamiento muy similar a los morteros de cal utilizados como referencia. Tras los ensayos de envejecimiento se ha visto que las propiedades biocidas de los morteros se mantienen.

  1. Performance of the CREAM calorimeter in accelerator beam test

    CERN Document Server

    Yoon, Y S; Bagliesi, M G; Bigongiari, G; Ganel, O; Han, J H; Hyun, H J; Jeon, J A; Kang, T G; Kim, H J; Kim, K C; Lee, J K; Lee, M H; Lutz, L; Maestro, P; Malinine, A; Marrocchesi, P S; Nam, S W; Park, H; Park, I H; Park, N H; Seo, E S; Sina, R; Wu, J; Yang, J; Zei, R; Zinn, S Y

    2010-01-01

    The CREAM calorimeter, designed to measure the spectra of cosmic-ray nuclei from under 1 TeV to 1000 TeV, is a 20 radiation length (X0) deep sampling calorimeter. The calorimeter is comprised of 20 layers of tungsten interleaved with 20 layers of scintillating fiber ribbons, and is preceded by a pair of graphite interaction targets providing about 0.42 proton interaction lengths (\\lambda int). The calorimeter was placed in one of CERN's SPS accelerator beams for calibration and testing. Beams of 150 GeV electrons were used for calibration, and a variety of electron, proton, and nuclear fragment beams were used to test the simulation model of the detector. In this paper we discuss the performance of the calorimeter in the electron beam and compare electron beam data with simulation results.

  2. Accelerated Leach Testing of GLASS: ALTGLASS Version 3.0

    Energy Technology Data Exchange (ETDEWEB)

    Trivelpiece, Cory L. [Savannah River Site (SRS), Aiken, SC (United States). Savannah River National Lab. (SRNL); Jantzen, Carol M. [Savannah River Site (SRS), Aiken, SC (United States). Savannah River National Lab. (SRNL); Crawford, Charles L. [Savannah River Site (SRS), Aiken, SC (United States). Savannah River National Lab. (SRNL)

    2016-12-31

    The Accelerated Leach Testing of GLASS (ALTGLASS) database is a collection of data from short- and long-term product consistency tests (PCT, ASTM C1285 A and B) on high level waste (HLW) as well as low activity waste (LAW) glasses. The database provides both U.S. and international researchers with an archive of experimental data for the purpose of studying, modeling, or validating existing models of nuclear waste glass corrosion. The ALTGLASS database is maintained and updated by researchers at the Savannah River National Laboratory (SRNL). This newest version, ALTGLASS Version 3.0, has been updated with an additional 503 rows of data representing PCT results from corrosion experiments conducted in the United States by the Savannah River National Laboratory, Pacific Northwest National Laboratory, Argonne National Laboratory, and the Vitreous State Laboratory (SRNL, PNNL, ANL, VSL, respectively) as well as the National Nuclear Laboratory (NNL) in the United Kingdom.

  3. Planning failure-censored constant-stress par tially accelerated life test

    Institute of Scientific and Technical Information of China (English)

    Ali A Ismail; Abdulhakim A Al-Babtain

    2015-01-01

    This article deals with the case of the failure-censored constant-stress partial y accelerated life test (CSPALT) for highly reliable materials or products assuming the Pareto distribution of the second kind. The maximum likelihood (ML) method is used to estimate the parameters of the CSPALT model. The performance of ML estimators is investigated via their mean square error. Also, the average confidence interval length (IL) and the associated co-verage probability (CP) are obtained. Moreover, optimum CSPALT plans that determine the optimal proportion of the test units al-located to each stress are developed. Such optimum test plans minimize the generalized asymptotic variance (GAV) of the ML estimators of the model parameters. For il ustration, Monte Carlo simulation studies are given and a real life example is provided.

  4. LED照明产品加速衰减试验方法研究%Accelerated Luminous Depreciation Testing for LED Lighting Products

    Institute of Scientific and Technical Information of China (English)

    钱诚; 孙博; 曹峻松

    2014-01-01

    With the application of energy-saving, environmental and durable LED lighting products, the reliability testing has become a pivot point for the large scale industrialization and popularization. The paper briefly introduces two methods to be respectively applied in the accelerated depreciation testing for the luminous flex of LED lighting products and the life of outdoor LED-driving power, which can sharply shorten the time for lifetime test, providing references for the LED lighting products’ reliability evaluation.

  5. ACCELERATORS Control system for the CSNS ion source test stand

    Science.gov (United States)

    Lu, Yan-Hua; Li, Gang; Ouyang, Hua-Fu

    2010-12-01

    A penning plasma surface H- ion source test stand for the CSNS has just been constructed at the IHEP. In order to achieve a safe and reliable system, nearly all devices of the ion source are designed to have the capability of both local and remote operation function. The control system consists of PLCs and EPICS real-time software tools separately serving device control and monitoring, PLC integration and OPI support. This paper summarizes the hardware and software implementation satisfying the requirements of the ion source control system.

  6. Accelerated radiation damage test facility using a 5 MV tandem ion accelerator

    Energy Technology Data Exchange (ETDEWEB)

    Wady, P.T., E-mail: paul.wady@manchester.ac.uk [Dalton Cumbrian Facility, University of Manchester, Westlakes Science & Technology Park, Moor Row, Cumbria CA24 3HA (United Kingdom); Draude, A.; Shubeita, S.M.; Smith, A.D.; Mason, N. [Dalton Cumbrian Facility, University of Manchester, Westlakes Science & Technology Park, Moor Row, Cumbria CA24 3HA (United Kingdom); Pimblott, S.M. [Dalton Cumbrian Facility, University of Manchester, Westlakes Science & Technology Park, Moor Row, Cumbria CA24 3HA (United Kingdom); School of Chemistry, University of Manchester, Oxford Road, Manchester M13 9PL (United Kingdom); Jimenez-Melero, E. [Dalton Cumbrian Facility, University of Manchester, Westlakes Science & Technology Park, Moor Row, Cumbria CA24 3HA (United Kingdom); School of Materials, University of Manchester, Oxford Road, Manchester M13 9PL (United Kingdom)

    2016-01-11

    We have developed a new irradiation facility that allows to perform accelerated damage tests of nuclear reactor materials at temperatures up to 400 °C using the intense proton (<100 μA) and heavy ion (≈10 μA) beams produced by a 5 MV tandem ion accelerator. The dedicated beam line for radiation damage studies comprises: (1) beam diagnosis and focusing optical components, (2) a scanning and slit system that allows uniform irradiation of a sample area of 0.5–6 cm{sup 2}, and (3) a sample stage designed to be able to monitor in-situ the sample temperature, current deposited on the sample, and the gamma spectrum of potential radio-active nuclides produced during the sample irradiation. The beam line capabilities have been tested by irradiating a 20Cr–25Ni–Nb stabilised stainless steel with a 3 MeV proton beam to a dose level of 3 dpa. The irradiation temperature was 356 °C, with a maximum range in temperature values of ±6 °C within the first 24 h of continuous irradiation. The sample stage is connected to ground through an electrometer to measure accurately the charge deposited on the sample. The charge can be integrated in hardware during irradiation, and this methodology removes uncertainties due to fluctuations in beam current. The measured gamma spectrum allowed the identification of the main radioactive nuclides produced during the proton bombardment from the lifetimes and gamma emissions. This dedicated radiation damage beam line is hosted by the Dalton Cumbrian Facility of the University of Manchester.

  7. Mir Cooperative Solar Array Project Accelerated Life Thermal Cycling Test

    Science.gov (United States)

    Hoffman, David J.; Scheiman, David A.

    1996-01-01

    The Mir Cooperative Solar Array (MCSA) project was a joint U.S./Russian effort to build a photovoltaic (PV) solar array and deliver it to the Russian space station Mir. The MCSA will be used to increase the electrical power on Mir and provide PV array performance data in support of Phase 1 of the International Space Station. The MCSA was brought to Mir by space shuttle Atlantis in November 1995. This report describes an accelerated thermal life cycle test which was performed on two samples of the MCSA. In eight months time, two MCSA solar array 'mini' panel test articles were simultaneously put through 24,000 thermal cycles. There was no significant degradation in the structural integrity of the test articles and no electrical degradation, not including one cell damaged early and removed from consideration. The nature of the performance degradation caused by this one cell is briefly discussed. As a result of this test, changes were made to improve some aspects of the solar cell coupon-to-support frame interface on the flight unit. It was concluded from the results that the integration of the U.S. solar cell modules with the Russian support structure would be able to withstand at least 24,000 thermal cycles (4 years on-orbit). This was considered a successful development test.

  8. THE DYNAMIC LEAP AND BALANCE TEST (DLBT): A TEST-RETEST RELIABILITY STUDY.

    Science.gov (United States)

    Jaffri, Abbis H; Newman, Thomas M; Smith, Brent I; John Miller, Sayers

    2017-08-01

    There is a need for new clinical assessment tools to test dynamic balance during typical functional movements. Common methods for assessing dynamic balance, such as the Star Excursion Balance Test, which requires controlled movement of body segments over an unchanged base of support, may not be an adequate measure for testing typical functional movements that involve controlled movement of body segments along with a change in base of support. The purpose of this study was to determine the reliability of the Dynamic Leap and Balance Test (DLBT) by assessing its test-retest reliability. It was hypothesized that there would be no statistically significant differences between testing days in time taken to complete the test. Reliability study. Thirty healthy college aged individuals participated in this study. Participants performed a series of leaps in a prescribed sequence, unique to the DLBT test. Time required by the participants to complete the 20-leap task was the dependent variable. Subjects leaped back and forth from peripheral to central targets alternating weight bearing from one leg to the other. Participants landed on the central target with the tested limb and were required to stabilize for two seconds before leaping to the next target. Stability was based upon qualitative measures similar to Balance Error Scoring System. Each assessment was comprised of three trials and performed on two days with a separation of at least six days. Two-way mixed ANOVA was used to analyze the differences in time to complete the sequence between the three trial averages of the two testing sessions. Intraclass Correlation Coefficient (ICC3,1) was used to establish between session test-retest reliability of the test trial averages. Significance was set a priori at p ≤ 0.05. No significant differences (p > 0.05) were detected between the two testing sessions. The ICC was 0.93 with a 95% confidence interval from 0.84 to 0.96. This test is a cost-effective, easy to

  9. Internal consistency and test-retest reliability of an instrumented functional reaching task using wireless electromyographic sensors.

    Science.gov (United States)

    Varghese, Rini; Hui-Chan, Christina W Y; Wang, Edward; Bhatt, Tanvi

    2014-10-01

    The purpose of this study was to establish the internal consistency and test-retest reliability of the electromyographic and accelerometric data sampled from the prime movers of the dominant arm during an antigravity, within-arm's length stand-reaching task without trunk restraint. Ten healthy young adults participated in two experimental sessions, approximately 7-10days apart. During each session, subjects performed 15 trials of both a flexion- and an abduction-reaching task. Surface EMG and acceleration using wireless sensors were sampled from the anterior and middle deltoid. Reliability was established using Cronbach's alpha, intraclass correlation coefficients (ICC 2, k) and standard error of measurements (SEM) for electromyographic reaction time, burst duration and normalized amplitude along with peak acceleration. Results indicated high degrees of inter-trial and test-retest reliability for flexion (Cronbach's α range=0.92-0.99; ICC range=0.82-0.92) as well as abduction (Cronbach's α range=0.94-0.99; ICC range=0.81-0.94) reaching. The SEM associated with response variables for flexion and abduction ranged from 1.55-3.26% and 3.33-3.95% of means, respectively. Findings from this study revealed that electromyographic and accelerometric data collected from prime movers of the arm during the relatively functional stand-reaching task were highly reproducible. Given its high reliability and portability, the proposed test could have applications in clinical and laboratory settings to quantify upper limb function.

  10. Reliability assessment of MEMS switches for space applications: laboratory and launch testing

    Science.gov (United States)

    O'Mahony, Conor; Olszewski, Oskar; Hill, Ronan; Houlihan, Ruth; Ryan, Cormac; Rodgers, Ken; Kelleher, Carmel; Duane, Russell; Hill, Martin

    2014-12-01

    A novel combination of ground-based and flight tests was employed to examine the reliability of capacitive radio-frequency microelectromechanical switches for use in space applications. Laboratory tests were initially conducted to examine the thermomechanical effects of packaging and space-like thermal stresses on the pull-in voltage of the devices; during this process it was observed that operational stability is highly dependent on the geometrical design of the switch and this must be taken in to account during the design stage. To further expose the switches to acceleration levels experienced during a space mission, they were launched on board a sounding rocket and then subjected to free-fall from a height of over 1.3 km with a resulting impact of over 3500g. Post launch analysis indicates that the switches are remarkably resilient to high levels of acceleration. Some evidence is also present to indicate that time-dependent strain relaxation in die attach epoxy materials may contribute to minor variations in device shape and performance.

  11. Cosmic acceleration without dark energy: background tests and thermodynamic analysis

    Energy Technology Data Exchange (ETDEWEB)

    Lima, J.A.S. [Departamento de Astronomia, Universidade de São Paulo, 55080-900, São Paulo, SP (Brazil); Graef, L.L. [Instituto de Física, Universidade de São Paulo, Rua do Matão travessa R, 05508-090, São Paulo, SP (Brazil); Pavón, D. [Departamento de Física, Universidad Autónoma de Barcelona, 08193 Bellaterra, Barcelona (Spain); Basilakos, Spyros, E-mail: jas.lima@iag.usp.br, E-mail: leilagraef@usp.br, E-mail: diego.pavon@uab.es, E-mail: svasil@academyofathens.gr [Academy of Athens, Research Center for Astronomy and Applied Mathematics, Soranou Efesiou 4, 11527, Athens (Greece)

    2014-10-01

    A cosmic scenario with gravitationally induced particle creation is proposed. In this model the Universe evolves from an early to a late time de Sitter era, with the recent accelerating phase driven only by the negative creation pressure associated with the cold dark matter component. The model can be interpreted as an attempt to reduce the so-called cosmic sector (dark matter plus dark energy) and relate the two cosmic accelerating phases (early and late time de Sitter expansions). A detailed thermodynamic analysis including possible quantum corrections is also carried out. For a very wide range of the free parameters, it is found that the model presents the expected behavior of an ordinary macroscopic system in the sense that it approaches thermodynamic equilibrium in the long run (i.e., as it nears the second de Sitter phase). Moreover, an upper bound is found for the Gibbons–Hawking temperature of the primordial de Sitter phase. Finally, when confronted with the recent observational data, the current 'quasi'-de Sitter era, as predicted by the model, is seen to pass very comfortably the cosmic background tests.

  12. Detailed Test Report for the Static Acceleration Testing of a cRIO Data Acquisition System

    Science.gov (United States)

    2014-10-01

    unit survives this acceleration test). The Environmental Engineering Branch ( EEB ) will use a centrifuge to apply a load of no less than 136 g’s for...external EEB data acquisition system (DAS).  A cRIO unit health monitoring sine wave will be generated by the cRIO unit and transmitted to the...external EEB DAS.  Acceleration data will be acquired via another accelerometer attached to the cRIO unit or test fixture, via slip rings in the

  13. Reliability Analysis and Test Planning using CAPO-Test for Existing Structures

    DEFF Research Database (Denmark)

    Sørensen, John Dalsgaard; Engelund, S.; Faber, M. H.

    2000-01-01

    of uncertainty related to this method are described. It is shown how the uncertainty in the transformation from the CAPO-test results to estimates of the concrete strength can be modeled. Further, the statistical uncertainty is modeled using Bayesian statistics. Finally, it is shown how reliability-based optimal...

  14. Accelerated gravity testing of aquitard core permeability and implications at formation and regional scale

    Directory of Open Access Journals (Sweden)

    W. A. Timms

    2015-03-01

    Full Text Available Evaluating the possibility of leakage through low permeability geological strata is critically important for sustainable water supplies, the extraction of fuels from strata such as coal beds, and the confinement of waste within the earth. The current work demonstrates that relatively rapid and reliable hydraulic conductivity (K measurement of aquitard cores using accelerated gravity can inform and constrain larger scale assessments of hydraulic connectivity. Steady state fluid velocity through a low K porous sample is linearly related to accelerated gravity (g-level in a centrifuge permeameter (CP unless consolidation or geochemical reactions occur. The CP module was custom designed to fit a standard 2 m diameter geotechnical centrifuge (550 g maximum with a capacity for sample dimensions of 30 to 100 mm diameter and 30 to 200 mm in length, and a maximum total stress of ~2 MPa at the base of the core. Formation fluids were used as influent to limit any shrink–swell phenomena which may alter the permeability. Vertical hydraulic conductivity (Kv results from CP testing of cores from three sites within the same regional clayey silt formation varied (10−7 to 10−9 m s−1, n = 14. Results at one of these sites (1.1 × 10−10 to 3.5 × 10−9 m s−1, n = 5 that were obtained in Kv values (3 × 10−9 m s−1 from pore pressure responses over several weeks within a 30 m clayey sequence. Core scale and in situ Kv results were compared with vertical connectivity within a regional flow model, and considered in the context of heterogeneity and preferential flow paths at site and formation scale. More reliable assessments of leakage and solute transport though aquitards over multi-decadal timescales can be achieved by accelerated core testing together with advanced geostatistical and numerical methods.

  15. A universal alternating immersion simulator for accelerated cyclic corrosion tests

    Energy Technology Data Exchange (ETDEWEB)

    Hassel, A.W.; Bonk, S.; Tsuri, S.; Stratmann, M. [Max-Planck-Institut fuer Eisenforschung GmbH, Duesseldorf (Germany)

    2008-02-15

    A new device for performing accelerated cyclic immersion tests is described. The main achievement is to realise a high cycling rate without a proportional increase in the test duration. The device is also capable of performing tests according to EU ISO 11130 specification. A minimal invasive drying system is used that neither heats air nor sample and the flow rate is still low as to prevent a mechanical delamination of paints or loose corrosion products. A multiple sample set-up is realised that provides individual reference electrodes. The random access through a multiplexer allows individual investigation of the samples even by electrochemical impedance spectroscopy under immersion conditions. The device and its test principle are applicable in both industrial and laboratorial scale applications. Two application examples are given to demonstrate the versatility of the alternating immersion tester. One addresses the corrosion protection performance of different zinc-coated steel sheets; the other quantifies the patina formation kinetics of low-alloyed steels with weathering properties. (Abstract Copyright [2008], Wiley Periodicals, Inc.)

  16. RELIABILITY OF TEST LANDS TARGETING IN BED-OF-NAILS STYLE TEST FIXTURE

    Institute of Scientific and Technical Information of China (English)

    2006-01-01

    A systematic, accurate and robust evaluating method for fine pitch printed circuit board (PCB) positioning assessment in testing fixture is developed. Targeting reliability of bed-of-nails tester is successfully evaluated by the 2D pattern transform. Probe offset vector with its Weibull and Gaussian distribution estimates are obtained for further investigation about the causes of misalignment on the basis of a batch tests for same kind of PCBs.

  17. Vibrational Stability of SRF Accelerator Test Facility at Fermilab

    Energy Technology Data Exchange (ETDEWEB)

    McGee, M.W.; Volk, J.T.; /Fermilab

    2009-05-01

    Recently developed, the Superconducting Radio Frequency (SRF) Accelerator Test Facilities at Fermilab support the International Linear Collider (ILC), High Intensity Neutrino Source (HINS), a new high intensity injector (Project X) and other future machines. These facilities; Meson Detector Building (MDB) and New Muon Lab (NML) have very different foundations, structures, relative elevations with respect to grade level and surrounding soil composition. Also, there are differences in the operating equipment and their proximity to the primary machine. All the future machines have stringent operational stability requirements. The present study examines both near-field and ambient vibration in order to develop an understanding of the potential contribution of near-field sources (e.g. compressors, ultra-high and standard vacuum equipment, klystrons, modulators, utility fans and pumps) and distant noise sources to the overall system displacements. Facility vibration measurement results and methods of possible isolation from noise sources are presented and discussed.

  18. Analysis of cracking in reinforced concrete using accelerated tests

    Energy Technology Data Exchange (ETDEWEB)

    Nguyen, Q.T.; Berthaud, Y. [Univ Paris 06, CNRS, ENSC, LMT, F-94235 Cachan (France); Care, S [CNRS, ENPC, LCPC, Inst Navier, LMSGC, F-77420 Champs Sur Marne (France); Millard, A. [CEA, DEN/DM2S/SEMT/LM2S, F-91191 Gif Sur Yvette (France)

    2007-02-15

    We present in this Note an experimental study-in a laboratory setup-of the mechanical effect (cracking of concrete) of corrosion on plates made of reinforced concrete. Due to the geometry it is possible to use digital image correlation to follow the evolution of strains induced by the corrosion of reinforcement. The corrosion is accelerated by the imposition of current density. Even if the representativeness of this test is still discussed, it allows one to record the entire strain history. The kinetics of cracking has been obtained and compared to a very simple model in which the increase of the corroded layer is modelled by a fictitious thermal load, the reinforcement remaining elastic and the concrete being damageable. (authors)

  19. Accelerators of particles and nuclear energy: the challenge of reliability; Aceleradores de partaculas y energia nuclear: el desafio de la fiabilidad

    Energy Technology Data Exchange (ETDEWEB)

    Fernandez Ramos, P.

    2011-07-01

    The use of particle accelerators for high energy industrial technology involves subjecting the reliability requirements more stringent than those that exist and become the main objective from the early stages of design.

  20. Method for the Accelerated Testing of the Durability of a Construction Binder using the Arrhenius Approach

    Science.gov (United States)

    Fridrichová, Marcela; Dvořák, Karel; Gazdič, Dominik

    2016-03-01

    The single most reliable indicator of a material's durability is its performance in long-term tests, which cannot always be carried out due to a limited time budget. The second option is to perform some kind of accelerated durability tests. The aim of the work described in this article was to develop a method for the accelerated durability testing of binders. It was decided that the Arrhenius equation approach and the theory of chemical reaction kinetics would be applied in this case. The degradation process has been simplified to a single quantifiable parameter, which became compressive strength. A model hydraulic binder based on fluidised bed combustion ash (FBC ash) was chosen as the test subject for the development of the method. The model binder and its hydration products were tested by high-temperature X-ray diffraction analysis. The main hydration product of this binder was ettringite. Due to the thermodynamic instability of this mineral, it was possible to verify the proposed method via long term testing. In order to accelerate the chemical reactions in the binder, four combinations of two temperatures (65 and 85°C) and two different relative humidities (14 and 100%) were used. The upper temperature limit was chosen because of the results of the high-temperature x-ray testing of the ettringite's decomposition. The calculation formulae for the accelerated durability tests were derived on the basis of data regarding the decrease in compressive strength under the conditions imposed by the four above-mentioned combinations. The mineralogical composition of the binder after degradation was also described. The final degradation product was gypsum under dry conditions and monosulphate under wet conditions. The validity of the method and formula was subsequently verified by means of long-term testing. A very good correspondence between the calculated and real values was achieved. The deviation of these values did not exceed 5 %. The designed and verified method

  1. Linear Accelerator Test Facility at LNF Conceptual Design Report

    CERN Document Server

    Valente, Paolo; Bolli, Bruno; Buonomo, Bruno; Cantarella, Sergio; Ceccarelli, Riccardo; Cecchinelli, Alberto; Cerafogli, Oreste; Clementi, Renato; Di Giulio, Claudio; Esposito, Adolfo; Frasciello, Oscar; Foggetta, Luca; Ghigo, Andrea; Incremona, Simona; Iungo, Franco; Mascio, Roberto; Martelli, Stefano; Piermarini, Graziano; Sabbatini, Lucia; Sardone, Franco; Sensolini, Giancarlo; Ricci, Ruggero; Rossi, Luis Antonio; Rotundo, Ugo; Stella, Angelo; Strabioli, Serena; Zarlenga, Raffaele

    2016-01-01

    Test beam and irradiation facilities are the key enabling infrastructures for research in high energy physics (HEP) and astro-particles. In the last 11 years the Beam-Test Facility (BTF) of the DA{\\Phi}NE accelerator complex in the Frascati laboratory has gained an important role in the European infrastructures devoted to the development and testing of particle detectors. At the same time the BTF operation has been largely shadowed, in terms of resources, by the running of the DA{\\Phi}NE electron-positron collider. The present proposal is aimed at improving the present performance of the facility from two different points of view: extending the range of application for the LINAC beam extracted to the BTF lines, in particular in the (in some sense opposite) directions of hosting fundamental physics and providing electron irradiation also for industrial users; extending the life of the LINAC beyond or independently from its use as injector of the DA{\\Phi}NE collider, as it is also a key element of the electron/...

  2. Advanced Beamline Design for Fermilab's Advanced Superconducting Test Accelerator

    Energy Technology Data Exchange (ETDEWEB)

    Prokop, Christopher [Northern Illinois Univ., DeKalb, IL (United States)

    2014-01-01

    The Advanced Superconducting Test Accelerator (ASTA) at Fermilab is a new electron accelerator currently in the commissioning stage. In addition to testing superconducting accelerating cavities for future accelerators, it is foreseen to support a variety of Advanced Accelerator R&D (AARD) experiments. Producing the required electron bunches with the expected flexibility is challenging. The goal of this dissertation is to explore via numerical simulations new accelerator beamlines that can enable the advanced manipulation of electron bunches. The work especially includes the design of a low-energy bunch compressor and a study of transverse-to-longitudinal phase space exchangers.

  3. Calibration of full-scale accelerated pavement testing data using long-term pavement performance data

    CSIR Research Space (South Africa)

    VdM Steyn, WJ

    2012-09-01

    Full Text Available Accelerated Pavement Testing (APT) has always been conducted with the objective of improving the understanding of real pavements under real traffic and environmental conditions. While APT provides an accelerated view of some of the major structural...

  4. Self-discrepancy: Long-term test-retest reliability and test-criterion predictive validity.

    Science.gov (United States)

    Watson, Neill; Bryan, Brandon C; Thrash, Todd M

    2016-01-01

    Long-term test-retest reliability and predictive test-criterion evidence of validity of scores on measures of the real-ideal self-discrepancy and of the real-ought self-discrepancy were tested over periods of 1 year and 3 years. A sample of 184 undergraduates completed at 2 time points 1 year apart 3 instruments that each measure the 2 self-discrepancies: the idiographic Self-Concept Questionnaire-Personal Constructs, the nonidiographic Self-Concept Questionnaire-Conventional Constructs, and the content-free Abstract Measures. A separate sample of 141 undergraduates completed the instruments 3 years apart. Both samples completed 3 depression instruments and 3 anxiety instruments at the second time point. Results of analyses using latent variables modeled with 3 observed variables showed substantial statistically significant test-retest reliabilities and significant test-criterion prediction of anxiety and depression on the real-ideal and real-ought discrepancy measures over both time periods. Results for the observed variables showed significant 1-year and 3-year reliabilities for scores on all self-discrepancy measures, as well as significant 1-year and 3-year predictive validity for scores on all self-discrepancy measures, except the abstract measure of real-ought discrepancy in predicting scores on all depression measures and on at least 1 anxiety measure. The findings support very strong long-term stabilities of the self-discrepancy personality constructs and their long-term associations with anxiety and depression.

  5. Optimal Constant-Stress Accelerated Degradation Test Plans Using Nonlinear Generalized Wiener Process

    Directory of Open Access Journals (Sweden)

    Zhen Chen

    2016-01-01

    Full Text Available Accelerated degradation test (ADT has been widely used to assess highly reliable products’ lifetime. To conduct an ADT, an appropriate degradation model and test plan should be determined in advance. Although many historical studies have proposed quite a few models, there is still room for improvement. Hence we propose a Nonlinear Generalized Wiener Process (NGWP model with consideration of the effects of stress level, product-to-product variability, and measurement errors for a higher estimation accuracy and a wider range of use. Then under the constraints of sample size, test duration, and test cost, the plans of constant-stress ADT (CSADT with multiple stress levels based on the NGWP are designed by minimizing the asymptotic variance of the reliability estimation of the products under normal operation conditions. An optimization algorithm is developed to determine the optimal stress levels, the number of units allocated to each level, inspection frequency, and measurement times simultaneously. In addition, a comparison based on degradation data of LEDs is made to show better goodness-of-fit of the NGWP than that of other models. Finally, optimal two-level and three-level CSADT plans under various constraints and a detailed sensitivity analysis are demonstrated through examples in this paper.

  6. Spinal appearance questionnaire: factor analysis, scoring, reliability, and validity testing.

    Science.gov (United States)

    Carreon, Leah Y; Sanders, James O; Polly, David W; Sucato, Daniel J; Parent, Stefan; Roy-Beaudry, Marjolaine; Hopkins, Jeffrey; McClung, Anna; Bratcher, Kelly R; Diamond, Beverly E

    2011-08-15

    Cross sectional. This study presents the factor analysis of the Spinal Appearance Questionnaire (SAQ) and its psychometric properties. Although the SAQ has been administered to a large sample of patients with adolescent idiopathic scoliosis (AIS) treated surgically, its psychometric properties have not been fully evaluated. This study presents the factor analysis and scoring of the SAQ and evaluates its psychometric properties. The SAQ and the Scoliosis Research Society-22 (SRS-22) were administered to AIS patients who were being observed, braced or scheduled for surgery. Standard demographic data and radiographic measures including Lenke type and curve magnitude were also collected. Of the 1802 patients, 83% were female; with a mean age of 14.8 years and mean initial Cobb angle of 55.8° (range, 0°-123°). From the 32 items of the SAQ, 15 loaded on two factors with consistent and significant correlations across all Lenke types. There is an Appearance (items 1-10) and an Expectations factor (items 12-15). Responses are summed giving a range of 5 to 50 for the Appearance domain and 5 to 20 for the Expectations domain. The Cronbach's α was 0.88 for both domains and Total score with a test-retest reliability of 0.81 for Appearance and 0.91 for Expectations. Correlations with major curve magnitude were higher for the SAQ Appearance and SAQ Total scores compared to correlations between the SRS Appearance and SRS Total scores. The SAQ and SRS-22 Scores were statistically significantly different in patients who were scheduled for surgery compared to those who were observed or braced. The SAQ is a valid measure of self-image in patients with AIS with greater correlation to curve magnitude than SRS Appearance and Total score. It also discriminates between patients who require surgery from those who do not.

  7. The reliability of knee joint position testing using electrogoniometry

    Directory of Open Access Journals (Sweden)

    Winter Adele

    2008-01-01

    Full Text Available Abstract Background The current investigation examined the inter- and intra-tester reliability of knee joint angle measurements using a flexible Penny and Giles Biometric® electrogoniometer. The clinical utility of electrogoniometry was also addressed. Methods The first study examined the inter- and intra-tester reliability of measurements of knee joint angles in supine, sitting and standing in 35 healthy adults. The second study evaluated inter-tester and intra-tester reliability of knee joint angle measurements in standing and after walking 10 metres in 20 healthy adults, using an enhanced measurement protocol with a more detailed electrogoniometer attachment procedure. Both inter-tester reliability studies involved two testers. Results In the first study, inter-tester reliability (ICC[2,10] ranged from 0.58–0.71 in supine, 0.68–0.79 in sitting and 0.57–0.80 in standing. The standard error of measurement between testers was less than 3.55° and the limits of agreement ranged from -12.51° to 12.21°. Reliability coefficients for intra-tester reliability (ICC[3,10] ranged from 0.75–0.76 in supine, 0.86–0.87 in sitting and 0.87–0.88 in standing. The standard error of measurement for repeated measures by the same tester was less than 1.7° and the limits of agreement ranged from -8.13° to 7.90°. The second study showed that using a more detailed electrogoniometer attachment protocol reduced the error of measurement between testers to 0.5°. Conclusion Using a standardised protocol, reliable measures of knee joint angles can be gained in standing, supine and sitting by using a flexible goniometer.

  8. Research on the overload protection reliability of moulded case circuit-breakers and its test device

    Institute of Scientific and Technical Information of China (English)

    LI Kui; LU Jian-guo; WU Yi; QIN Zhi-jun; YAO Dong-mei

    2007-01-01

    This paper analyzed the reliability and put forward the reliability index of overload protection for moulded case circuit breaker. The success rate was adopted as its reliability index of overload protection. Based on the reliability index and the reliability level, the reliability examination plan was analyzed and a test device for the overload protection of moulded case circuit-breaker was developed. In the reliability test of overload protection, two power sources were used, which reduced the time of conversion and regulation between two different test currents in the overload protection test, which made the characteristic test more accurate. The test device was designed on the base of a Windows system, which made its operation simple and friendly.

  9. Failure modes and effects criticality analysis and accelerated life testing of LEDs for medical applications

    Science.gov (United States)

    Sawant, M.; Christou, A.

    2012-12-01

    While use of LEDs in Fiber Optics and lighting applications is common, their use in medical diagnostic applications is not very extensive. Since the precise value of light intensity will be used to interpret patient results, understanding failure modes [1-4] is very important. We used the Failure Modes and Effects Criticality Analysis (FMECA) tool to identify the critical failure modes of the LEDs. FMECA involves identification of various failure modes, their effects on the system (LED optical output in this context), their frequency of occurrence, severity and the criticality of the failure modes. The competing failure modes/mechanisms were degradation of: active layer (where electron-hole recombination occurs to emit light), electrodes (provides electrical contact to the semiconductor chip), Indium Tin Oxide (ITO) surface layer (used to improve current spreading and light extraction), plastic encapsulation (protective polymer layer) and packaging failures (bond wires, heat sink separation). A FMECA table is constructed and the criticality is calculated by estimating the failure effect probability (β), failure mode ratio (α), failure rate (λ) and the operating time. Once the critical failure modes were identified, the next steps were generation of prior time to failure distribution and comparing with our accelerated life test data. To generate the prior distributions, data and results from previous investigations were utilized [5-33] where reliability test results of similar LEDs were reported. From the graphs or tabular data, we extracted the time required for the optical power output to reach 80% of its initial value. This is our failure criterion for the medical diagnostic application. Analysis of published data for different LED materials (AlGaInP, GaN, AlGaAs), the Semiconductor Structures (DH, MQW) and the mode of testing (DC, Pulsed) was carried out. The data was categorized according to the materials system and LED structure such as AlGaInP-DH-DC, Al

  10. Reliability of Self-Report Measures of Drug Use in Prevention Research: Evaluation of the Project SMART Questionnaire via the Test-Retest Reliability Matrix.

    Science.gov (United States)

    Graham, John W.; And Others

    1984-01-01

    Describes an evaluation of a self-report questionnaire administered to seventh graders (N=396). Using the test-retest reliability matrix, eight of nine drug-use indices appeared to have acceptable to good reliability. The three measures included in the test-retest reliability matrix provide stronger evidence for good reliability than could any…

  11. Feasibility and Reliability of Physical Fitness Tests in Older Adults with Intellectual Disability: A Pilot Study

    Science.gov (United States)

    Hilgenkamp, Thessa I. M.; van Wijck, Ruud; Evenhuis, Heleen M.

    2012-01-01

    Background: Physical fitness is relevant for wellbeing and health, but knowledge on the feasibility and reliability of instruments to measure physical fitness for older adults with intellectual disability is lacking. Methods: Feasibility and test-retest reliability of a physical fitness test battery (Box and Block Test, Response Time Test, walking…

  12. Feasibility and Reliability of Physical Fitness Tests in Older Adults with Intellectual Disability: A Pilot Study

    Science.gov (United States)

    Hilgenkamp, Thessa I. M.; van Wijck, Ruud; Evenhuis, Heleen M.

    2012-01-01

    Background: Physical fitness is relevant for wellbeing and health, but knowledge on the feasibility and reliability of instruments to measure physical fitness for older adults with intellectual disability is lacking. Methods: Feasibility and test-retest reliability of a physical fitness test battery (Box and Block Test, Response Time Test, walking…

  13. Voltage stress effects on microcircuit accelerated life test failure rates

    Science.gov (United States)

    Johnson, G. M.

    1976-01-01

    The applicability of Arrhenius and Eyring reaction rate models for describing microcircuit aging characteristics as a function of junction temperature and applied voltage was evaluated. The results of a matrix of accelerated life tests with a single metal oxide semiconductor microcircuit operated at six different combinations of temperature and voltage were used to evaluate the models. A total of 450 devices from two different lots were tested at ambient temperatures between 200 C and 250 C and applied voltages between 5 Vdc and 15 Vdc. A statistical analysis of the surface related failure data resulted in bimodal failure distributions comprising two lognormal distributions; a 'freak' distribution observed early in time, and a 'main' distribution observed later in time. The Arrhenius model was shown to provide a good description of device aging as a function of temperature at a fixed voltage. The Eyring model also appeared to provide a reasonable description of main distribution device aging as a function of temperature and voltage. Circuit diagrams are shown.

  14. Accelerated atmospheric corrosion testing of electroplated gold mirror coatings

    Science.gov (United States)

    Chu, C.-T.; Alaan, D. R.; Taylor, D. P.

    2010-08-01

    Gold-coated mirrors are widely used in infrared optics for industrial, space, and military applications. These mirrors are often made of aluminum or beryllium substrates with polished nickel plating. Gold is deposited on the nickel layer by either electroplating or vacuum deposition processes. Atmospheric corrosion of gold-coated electrical connectors and contacts was a well-known problem in the electronic industry and studied extensively. However, there is limited literature data that correlates atmospheric corrosion to the optical properties of gold mirror coatings. In this paper, the atmospheric corrosion of different electroplated gold mirror coatings were investigated with an accelerated mixed flowing gas (MFG) test for up to 50 days. The MFG test utilizes a combination of low-level air pollutants, humidity, and temperatures to achieve a simulated indoor environment. Depending on the gold coating thickness, pore corrosion started to appear on samples after about 10 days of the MFG exposure. The corrosion behavior of the gold mirror coatings demonstrated the porous nature of the electroplated gold coatings as well as the variation of porosity to the coating thickness. The changes of optical properties of the gold mirrors were correlated to the morphology of corrosion features on the mirror surface.

  15. Accelerated indoor durability testing of polymeric photovoltaic encapsulation materials

    Science.gov (United States)

    Oreski, Gernot

    2010-08-01

    The aim of these investigations was to determine the influence of the relevant load parameters temperature and humidity on the degradation behavior of selected polymeric PV encapsulation materials. A test program concerning three accelerated artificial ageing tests was set up and a comprehensive study of the selected candidate materials and its degradation behavior was done. To assess the long term performance and durability of materials, it was necessary not only to measure the deterioration of macroscopic physical properties, but also to gain information about degradation processes taking place at a molecular level. Therefore, the material properties and the aging behaviour were characterized by infrared spectroscopy, by UV/VIS spectroscopy, by differential scanning calorimetry, by dynamical mechanical analysis and by tensile tests. By IR spectroscopy no significant thermal oxidation was detected for all investigated materials. But UV/VIS spectroscopy showed a significant drop in solar transmittance and reflectance values. Yellowing was observed due to the formation of chromophoric degradation products. For all materials a significant decrease in ultimate mechanical properties due to chemical aging was measured. For both backsheet materials the changes in ultimate mechanical properties can be attributed nearly exclusiveley to the polyester layer. On the other hand, a stiffening of all materials due to physical aging was observed within the first 1000h of damp heat testing. For the backsheet laminates, delamination at the edges was observed. Generally, higher temperature levels during exposure induced faster rate of chemical and physical aging. High humidity levels showed to be less influential on polymer degradation than temperature.

  16. Criterion validity and reliability of a smartphone delivered sub-maximal fitness test for people with type 2 diabetes

    DEFF Research Database (Denmark)

    Brinklov, Cecilie Fau; Thorsen, Ida Kær; Karstoft, Kristian

    2016-01-01

    Background: Prevention of multi-morbidities following non-communicable diseases requires a systematic registration of adverse modifiable risk factors, including low physical fitness. The aim of the study was to establish criterion validity and reliability of a smartphone app (InterWalk) delivered...... calorimetry and the acceleration (vector magnitude) from the smartphone was obtained. The vector magnitude was used to predict VO2peak along with the co-variates weight, height and sex. The validity of the algorithm was tested when the smartphone was placed in the right pocket of the pants or jacket....... The algorithm was validated using leave-one-out cross validation. Test-retest reliability was tested in a subset of participants (N = 10). Results: The overall VO2peak prediction of the algorithm (R2) was 0.60 and 0.45 when the smartphone was placed in the pockets of the pants and jacket, respectively (p

  17. Design and testing of a dc ion injector suitable for accelerator-driven transmutation

    Energy Technology Data Exchange (ETDEWEB)

    Schneider, J.D.; Meyer, E.; Stevens, R.R. Jr.; Hansborough, L.; Sherman, J.

    1994-08-01

    For a number of years, Los Alamos have collaborated with a team of experimentalists at Chalk River Labs who were pursuing the development of the front end of a high power cw proton accelerator. With the help of internal laboratory funding and modest defense conversion funds, we have set up and operated the accelerator at Los Alamos Operational equipment includes a slightly modified Chalk River Injector Test Stand (CRITS) including a 50 keV proton injector and a 1.25 MeV radio-frequency quadrupole (RFQ) with a klystrode rf power system. Many of the challenges involved in operating an rf linear accelerator to provide neutrons for an accelerator-driven reactor are encountered at the front (low energy) end of this system. The formation of the ion beam, the control of the beam parameters, and the focusing and matching of a highly space-charge-dominated beam are major problems. To address the operating problems in this critical front end, the Accelerator Operations and Technology Division at the Los Alamos National Laboratory has designed the APDF (Accelerator Prototype Demonstration Facility). The front end of this facility is a 75 keV, high-current, ion injector which has been assembled and is now being tested. This paper discusses the design modifications required in going from the 50 keV CRITS injector to the higher current, 75 keV injector. Major innovative changes were made in the design of this injector. This design eliminates all the control electronics and most of the ion source equipment at high potential. Also, a new, high-quality, ion-extractor system has been built. A dual-solenoid lens will be used in the low energy beam transport (LEBT) line to provide the capability of matching the extracted beam to a high-current ADTT linac. This new injector is the first piece of hardware in the APDF program and will be used to develop the long-term, reliable cw beam operation required for ADIT applications.

  18. Accelerated stress testing and diagnostic analysis of degradation in CdTe solar cells

    Science.gov (United States)

    Albin, David S.

    2008-08-01

    Solar cell module reliability is inextricably linked to cell-level reliability. This is particularly so with thin-film technologies. In CdTe, reliability issues historically associate with back contact stability and the use of Cu as an extrinsic dopant. Using a simple approach by which identical cells are heated under open-circuit bias and 1-sun illumination, degradation activation energies of 0.63 and 2.94 eV in laboratory-scale CdS/CdTe devices were identified in the accelerated stress temperature range of 60 to 120 °C. At lower stress temperatures, cell performance changes were linearly correlated with changes in both fill factor (FF) and short-circuit current (Jsc). At higher stress temperatures, changes in efficiency were correlated with changes in FF and open-circuit voltage (Voc). The measured activation energy of 0.63 is associated with Cu-diffusion. During the early stage of stress testing, which may provide additional back contact annealing, improvements in FF were due to Cu-diffusion. Decreased performance observed at longer stress times (decreased FF and Voc), according to a two-diode Pspice model, were due to both increased space-charge recombination (near the junction) and decreased recombination in the bulk. Kirkendall void formation (S-outdiffusion) at the CdS/CdTe interface is given as responsible for the 2.9 eV degradation mechanism.

  19. Test-retest reliability of an emotion maintenance task.

    Science.gov (United States)

    Broome, Rose; Gard, David E; Mikels, Joseph A

    2012-01-01

    Research on working memory has suggested domain-specific components for visual, verbal, and spatial information, and more recently for emotion. Affective working memory has been proposed as the set of processes involved in the maintenance of emotions to guide behaviour. The current study examined the reliability of an emotion maintenance/affective working memory task over two experimental sessions separated by one week. Subjective accuracy based on individual ratings was found to correlate over time and was highest for negatively valenced pictures. Results suggest that this paradigm is a reliable measure of emotion maintenance, underscoring the utility of this measure as an assessment tool for normative and clinical populations.

  20. One-month test-retest reliability of the ImPACT test battery.

    Science.gov (United States)

    Schatz, Philip; Ferris, Charles S

    2013-08-01

    In order to better understand the test-retest reliability of the ImPACT test battery, 25 undergraduate students completed two ImPACT tests across a time frame of 4 weeks between assessments. Participants had not previously completed ImPACT and had no history of concussion. Pearson's correlation coefficients (r) and intraclass correlation coefficients (ICCs) were as follows: Verbal Memory = .66/.79 (r/ICC), Visual Memory = .43/.60, Visual Motor Speed = .78/.88, Reaction Time = .63/.77, and Total Symptoms = .75/.81. Dependent sample t-tests revealed significant improvement on only Visual Motor Speed composite scores. Reliable Change Indices showed a significant number of participants fell outside 80% and 95% confidence intervals for only Visual Motor Speed scores (but no other indices), whereas all scores were within 80% and 95% confidence intervals using regression-based measures. Results suggest that repeated exposure to the ImPACT test may result in significant improvements in the physical mechanics of how college students interact with the test (e.g., performance on Visual Motor Speed), but repeated exposure across 1 month does not result in practice effects in memory performance or reaction time.

  1. Reliability, construct and discriminative validity of clinical testing in subjects with and without chronic neck pain

    DEFF Research Database (Denmark)

    Jørgensen, René; Ris Hansen, Inge; Falla, Deborah

    2014-01-01

    BACKGROUND: The reliability of clinical tests for the cervical spine has not been adequately evaluated. Six cervical clinical tests, which are low cost and easy to perform in clinical settings, were tested for intra- and inter-examiner reliability, and two performance tests were assessed for test......-Cervical Flexion Test (CCFT), Range of Movement (ROM), Joint Position Error (JPE), Gaze Stability (GS), Smooth Pursuit Neck Torsion Test (SPNTT), and neuromuscular control of the Deep Cervical Extensors (DCE). Test-retest reliability was assessed for Postural Control (SWAY) and Pressure Pain Threshold (PPT) over...

  2. Testing reliability of raster - report of experiment with Kerckhoffs students

    NARCIS (Netherlands)

    Vriezekolk, Eelco

    2014-01-01

    We are working on the development of an availability risk assessment method for telecommunication services, called Raster. From previous research we know that Raster can produce assessments with reasonable effort, but we have not yet shown that its results are reliable (repeatable) and accurate (cor

  3. Test-retest reliability of innovated strength tests for hip muscles.

    Directory of Open Access Journals (Sweden)

    Christophe Meyer

    Full Text Available The burden of hip muscles weakness and its relation to other impairments has been well documented. It is therefore a pre-requisite to have a reliable method for clinical assessment of hip muscles function allowing the design and implementation of a proper strengthening program. Motor-driven dynamometry has been widely accepted as the gold-standard for lower limb muscle strength assessment but is mainly related to the knee joint. Studies focusing on the hip joint are less exhaustive and somewhat discrepant with regard to optimal participants position, consequently influencing outcome measures. Thus, we aimed to develop a standardized test setup for the assessment of hip muscles strength, i.e. flexors/extensors and abductors/adductors, with improved participant stability and to define its psychometric characteristics. Eighteen participants performed unilateral isokinetic and isometric contractions of the hip muscles in the sagittal and coronal plane at two separate occasions. Peak torque and normalized peak torque were measured for each contraction. Relative and absolute measures of reliability were calculated using the intraclass correlation coefficient and standard error of measurement, respectively. Results from this study revealed higher levels of between-day reliability of isokinetic/isometric hip abduction/flexion peak torque compared to existing literature. The least reliable measures were found for hip extension and adduction, which could be explained by a less efficient stabilization technique. Our study additionally provided a first set of reference normalized data which can be used in future research.

  4. Test re-test reliability and construct validity of the star-track test of manual dexterity

    Directory of Open Access Journals (Sweden)

    Niels Kildebro

    2015-04-01

    Full Text Available Objectives. We wished to determine test re-test reliability and construct validity of the star-track test of manual dexterity.Design. Test re-test reliability was examined in a controlled study. Construct validity was tested in a blinded randomized crossover study.Setting. The study was performed at a university hospital in Denmark.Participants. A total of 11 subjects for test re-test and 20 subjects for the construct validity study were included. All subjects were healthy volunteers.Intervention. The test re-test trial had two measurements with 2 days pause in between. The interventions in the construct validity study included baseline measurement, intervention 1: fatigue, intervention 2: stress, and intervention 3: fatigue and stress. There was a 2 day pause between each intervention.Main outcome measure. An integrated measure of completion time and number of errors was used.Results. All participants completed the study (test re-test n = 11; construct validity n = 20. The test re-testshowed a strong Pearson product-moment correlation (r = 0.90, n = 11, P < 0.01 with no sign of learning effect. The 20 subjects in the construct validity trial were randomized to the order of the four interventions, so that all subjects completed each intervention once. A repeated measures ANOVA determined that mean integrated measure differed between interventions (p = 0.002. Post hoc tests using Bonferroni correction revealed that compared with baseline all interventions had significantly higher integrated scores ranging from 47–59% difference in mean.Conclusion. The star track test of manual dexterity had a strong test re-test reliability, and was able to discriminate between a subject’s normal manual dexterity and dexterity after exposure to fatigue and/or stress.

  5. Test of understanding of vectors: A reliable multiple-choice vector concept test

    Science.gov (United States)

    Barniol, Pablo; Zavala, Genaro

    2014-06-01

    In this article we discuss the findings of our research on students' understanding of vector concepts in problems without physical context. First, we develop a complete taxonomy of the most frequent errors made by university students when learning vector concepts. This study is based on the results of several test administrations of open-ended problems in which a total of 2067 students participated. Using this taxonomy, we then designed a 20-item multiple-choice test [Test of understanding of vectors (TUV)] and administered it in English to 423 students who were completing the required sequence of introductory physics courses at a large private Mexican university. We evaluated the test's content validity, reliability, and discriminatory power. The results indicate that the TUV is a reliable assessment tool. We also conducted a detailed analysis of the students' understanding of the vector concepts evaluated in the test. The TUV is included in the Supplemental Material as a resource for other researchers studying vector learning, as well as instructors teaching the material.

  6. Validity and reliability of tests determining performance-related components of wheelchair basketball

    NARCIS (Netherlands)

    De Groot, Sonja; Balvers, Inge J. M.; Kouwenhoven, Sanne M.; Janssen, Thomas W. J.

    2012-01-01

    The purpose of this study was to investigate the reliability and validity of wheelchair basketball field tests. Nineteen wheelchair basketball players performed 10 test items twice to determine the reliability. The validity of the tests was assessed by relating the scores to the players'

  7. Validity and reliability of tests determining performance-related components of wheelchair basketball

    NARCIS (Netherlands)

    De Groot, Sonja; Balvers, Inge J. M.; Kouwenhoven, Sanne M.; Janssen, Thomas W. J.

    2012-01-01

    The purpose of this study was to investigate the reliability and validity of wheelchair basketball field tests. Nineteen wheelchair basketball players performed 10 test items twice to determine the reliability. The validity of the tests was assessed by relating the scores to the players' classificat

  8. The Five-Point Test : Reliability, validity and normative data for children and adults

    NARCIS (Netherlands)

    Tucha, L.I.; Aschenbrenner, S.; Koerts, J.; Lange, K.W.

    2012-01-01

    The present study provides normative data from a sample of 257 healthy children and 608 adults on a modified version of the Five-Point Test (5PT). The 5PT is a structured and standardized test measuring figural fluency functions. Interrater reliability, test-retest-reliability and construct validity

  9. Multiple Choice and True/False Tests: Reliability Measures and Some Implications of Negative Marking

    Science.gov (United States)

    Burton, Richard F.

    2004-01-01

    The standard error of measurement usefully provides confidence limits for scores in a given test, but is it possible to quantify the reliability of a test with just a single number that allows comparison of tests of different format? Reliability coefficients do not do this, being dependent on the spread of examinee attainment. Better in this…

  10. The timed "up and go" test : Reliability and validity in persons with unilateral lower limb amputation

    NARCIS (Netherlands)

    Schoppen, Tanneke; Boonstra, Antje; Groothoff, JW; de Vries, J; Goeken, LNH; Eisma, Willem

    Objective: To determine the interrater and interrater reliability and the validity of the Timed "up and go" test as a measure for physical mobility in elderly patients with an amputation of the lower extremity. Design: To test interrater reliability, the test was performed for two observers at

  11. Construction and Evaluation of Reliability and Validity of Reasoning Ability Test

    Science.gov (United States)

    Bhat, Mehraj A.

    2014-01-01

    This paper is based on the construction and evaluation of reliability and validity of reasoning ability test at secondary school students. In this paper an attempt was made to evaluate validity, reliability and to determine the appropriate standards to interpret the results of reasoning ability test. The test includes 45 items to measure six types…

  12. Validity and reliability of tests determining performance-related components of wheelchair basketball

    NARCIS (Netherlands)

    De Groot, Sonja; Balvers, Inge J. M.; Kouwenhoven, Sanne M.; Janssen, Thomas W. J.

    2012-01-01

    The purpose of this study was to investigate the reliability and validity of wheelchair basketball field tests. Nineteen wheelchair basketball players performed 10 test items twice to determine the reliability. The validity of the tests was assessed by relating the scores to the players' classificat

  13. Reliability of pre- and intraoperative tests for biliary lithiasis

    Energy Technology Data Exchange (ETDEWEB)

    Escallon, A. Jr.; Rosales, W.; Aldrete, J.S.

    1985-05-01

    The records of 242 patients, operated consecutively for biliary lithiasis, were analyzed to determine the reliability of oral cholecystography (OCG), ultrasonography (US), and HIDA in detecting biliary calculi. Preoperative interpretations were correlated to operative findings. OCG obtained in 138 patients was accurate in 92%. US obtained in 150 was correct in 89%. The accuracy of HIDA was 92% in acute and 78% in chronic cholecystitis. Intraoperative cholangiography (IOC) done in 173 patients indicated the need for exploratory choledochotomy in 24; 21 had choledocholithiasis. These observations suggest that OCG and US are very accurate, but not infallible, in detecting cholelithiasis. US should be done first; when doubt persists, the addition of OCG allows the preoperative diagnosis of gallstones in 97% of the cases. HIDA is highly accurate but not infallible in detecting acute calculous cholecystitis. IOC is very reliable in detecting choledocholithiasis; thus, its routine is justifiable.

  14. Reliability of pre- and intraoperative tests for biliary lithiasis.

    Science.gov (United States)

    Escallon, A; Rosales, W; Aldrete, J S

    1985-01-01

    The records of 242 patients, operated consecutively for biliary lithiasis, were analyzed to determine the reliability of oral cholecystography (OCG), ultrasonography (US), and HIDA in detecting biliary calculi. Preoperative interpretations were correlated to operative findings. OCG obtained in 138 patients was accurate in 92%. US obtained in 150 was correct in 89%. The accuracy of HIDA was 92% in acute and 78% in chronic cholecystitis. Intraoperative cholangiography (IOC) done in 173 patients indicated the need for exploratory choledochotomy in 24; 21 had choledocholithiasis. These observations suggest that OCG and US are very accurate, but not infallible, in detecting cholelithiasis. US should be done first; when doubt persists, the addition of OCG allows the preoperative diagnosis of gallstones in 97% of the cases. HIDA is highly accurate but not infallible in detecting acute calculous cholecystitis. IOC is very reliable in detecting choledocholithiasis; thus, its routine is justifiable. PMID:3888131

  15. Development of a Rapid, Reliable Genetic Test for Pseudoxanthoma Elasticum

    OpenAIRE

    Shi, Yanggu; Terry, Sharon F.; Terry, Patrick F.; Bercovitch, Lionel G.; Gerard, Gary F.

    2007-01-01

    Mutations in the human ABCC6 gene cause pseudoxanthoma elasticum (PXE), a hereditary disorder that impacts the skin, eyes, and cardiovascular system. Currently, the diagnosis of PXE is based on physical findings and histological examination of a biopsy of affected skin. We have combined two simple, polymerase chain reaction (PCR)-based methods to develop a rapid, reliable genetic assay for the majority of known PXE mutations. After PCR amplification and heteroduplex formation, mutations in ex...

  16. The PIVKA II test: the first reliable coagulation test for autopsy investigations.

    Science.gov (United States)

    Rutty, G N; Woolley, A; Brookfield, C; Shepherd, F; Kitchen, S

    2003-06-01

    To date there is no routinely used reliable diagnostic test that can be performed in the post-mortem period to investigate whether a deceased had a coagulation disorder. This paper describes a series of experiments to assess the use of an antigen-based method to investigate the vitamin K-dependent factor II function in the deceased. It illustrates that by using this approach the functional status of factor II can be investigated in the post-mortem period. The abnormal proteins that are investigated by this method appear to remain stable for at least 72 h and potentially up to at least 7 days. The method that is illustrated could thus be reliably used in the post-mortem period to identify a natural or drug-induced factor II abnormality. The potential for other protein components of the coagulation cascade to be investigated by similar antigen-based methodology is suggested.

  17. Microelectronics Reliability

    Science.gov (United States)

    2017-01-17

    convey any rights or permission to manufacture, use, or sell any patented invention that may relate to them. This report was cleared for public release...testing for reliability prediction of devices exhibiting multiple failure mechanisms. Also presented was an integrated accelerating and measuring ...13  Table 2  T, V, F and matrix versus  measured  FIT

  18. Reliability of the Groningen Fitness Test for the Elderly

    NARCIS (Netherlands)

    Lemmink, KAPM; Han, K; de Greef, MHG; Rispens, P; Stevens, M

    2001-01-01

    Several items of the Groningen Fitness Test for the Elderly (GFE) were tested. The GFE tests were administered twice, with 1 week between sessions. The participants were 458 independently living adults >55 yeats of age. For most tests, there was reasonable agreement between sessions, indicating abso

  19. Status and plans for a SRF accelerator test faciliy at Fermilab

    CERN Document Server

    Leibfritz, J; Carlson, K; Chase, B; Church, M; Harms, E; Klebaner, A; Kucera, M; Lackey, S; Martinez, A; Nagaitsev, S; Nobrega, L; Piot, P; Reid, J; Wendt, M; Wesseln, S

    2012-01-01

    A superconducting RF accelerator test facility is being constructed at Fermilab. The existing New Muon Lab (NML) building is being converted for this facility. The accelerator will consist of an electron gun, injector, beam acceleration section consisting of 3 TTF-type or ILC-type cryomodules, multiple downstream beam lines for testing diagnostics and conducting various beam tests, and a high power beam dump. When completed, it is envisioned that this facility will initially be capable of generating an 810 MeV electron beam with ILC beam intensity. Expansion plans of the facility are underway that will provide the capability to upgrade the accelerator to a total beam energy of 1.5 GeV. In addition to testing accelerator components, this facility will be used to test RF power equipment, instrumentation, LLRF and controls systems for future SRF accelerators such as the ILC and Project-X. This paper describes the current status and overall plans for this facility.

  20. Accelerated stability testing of organic photovoltaics using concentrated sunlight

    DEFF Research Database (Denmark)

    Katz, Eugene A.; Manor, Assaf; Mescheloff, Asaf;

    2012-01-01

    We suggest to use concentrated sunlight for accelerated studies of light-induced mechanisms in the degradation of organic photovoltaics (OPV) based on the polymer (P3HT)/fullerene (PCBM) bulk heterojunctions. Two particular cases of the degradation are reported.......We suggest to use concentrated sunlight for accelerated studies of light-induced mechanisms in the degradation of organic photovoltaics (OPV) based on the polymer (P3HT)/fullerene (PCBM) bulk heterojunctions. Two particular cases of the degradation are reported....

  1. RELIABILITY OF CERTAIN TESTS FOR EVALUATION OF JUDO TECHNIQUES

    Directory of Open Access Journals (Sweden)

    Slavko Obadov

    2007-05-01

    Full Text Available The sample included 106 judokas. Assessment of the level of mastership of judo techniques was carried out by evaluation of fi ve competent studies. Each subject performed a technique three times and each performance was evaluated by the judges. In order to evaluate measurement of each technique, Cronbach’s coeffi cient of reliability  was calculated. During the procedure the subjects's results were also transformed to factor scores i.e. the results of each performer at the main component of evaluation in the fi ve studies. These factor scores could be used in the subsequent procedure of multivariant statistical analysis.

  2. Test-retest reliability and task order effects of emotional cognitive tests in healthy subjects.

    Science.gov (United States)

    Adams, Thomas; Pounder, Zoe; Preston, Sally; Hanson, Andy; Gallagher, Peter; Harmer, Catherine J; McAllister-Williams, R Hamish

    2016-11-01

    Little is known of the retest reliability of emotional cognitive tasks or the impact of using different tasks employing similar emotional stimuli within a battery. We investigated this in healthy subjects. We found improved overall performance in an emotional attentional blink task (EABT) with repeat testing at one hour and one week compared to baseline, but the impact of an emotional stimulus on performance was unchanged. Similarly, performance on a facial expression recognition task (FERT) was better one week after a baseline test, though the relative effect of specific emotions was unaltered. There was no effect of repeat testing on an emotional word categorising, recall and recognition task. We found no difference in performance in the FERT and EABT irrespective of task order. We concluded that it is possible to use emotional cognitive tasks in longitudinal studies and combine tasks using emotional facial stimuli in a single battery.

  3. Development, reliability, and validity testing of the Ethical Behavior Test: a measure for nurses' ethical behavior.

    Science.gov (United States)

    Dierckx de Casterlé, B; Grypdonck, M; Vuylsteke-Wauters, M

    1997-01-01

    The need for reliable and valid measures for ethical behavior of nurses has encouraged the authors to develop a new instrument to measure students' ethical behavior in daily nursing dilemmas. Characteristic of the instrument presented is the inclusion of two fundamental components of ethical behavior: (1) ethical reasoning (and the resulting decision), and (2) the actual implementation of the ethical decision. As for many instruments, Kohlberg's theory of moral development has been used as the conceptual framework. However, Kohlberg's abstract justice orientation was refined by a care perspective and representative nursing dilemmas were used to make the instrument conceptually more appropriate for measuring nurses' ethical behavior. The analysis of the psychometric properties of the instrument has provided several relevant indications for the reliability and validity of the ethical reasoning and implementation scores. The revealed inconsistencies in the Ethical Behavior Test could be satisfactorily interpreted in terms of Kohlberg's theory and related empirical research findings, supporting the reliability of the ethical behavior scores. The content validity rests upon the careful development of the instrument resulting in an optimal mix of dilemmas, arguments and care situations to reveal nurses' ethical behavior and in a substantial degree of correspondence between the concept and operationalization. The congruency between the patterns of ethical behavior and Kohlberg's theoretical insights about ethical reasoning and practice support the construct validity of the instrument.

  4. Development of a rapid, reliable genetic test for pseudoxanthoma elasticum.

    Science.gov (United States)

    Shi, Yanggu; Terry, Sharon F; Terry, Patrick F; Bercovitch, Lionel G; Gerard, Gary F

    2007-02-01

    Mutations in the human ABCC6 gene cause pseudoxanthoma elasticum (PXE), a hereditary disorder that impacts the skin, eyes, and cardiovascular system. Currently, the diagnosis of PXE is based on physical findings and histological examination of a biopsy of affected skin. We have combined two simple, polymerase chain reaction (PCR)-based methods to develop a rapid, reliable genetic assay for the majority of known PXE mutations. After PCR amplification and heteroduplex formation, mutations in exon 24 and exon 28 of the ABCC6 gene were detected with Surveyor nuclease, which cleaves double-stranded DNA at any mismatch site. Mutations originating from deletion of a segment of the ABCC6 gene between exon 23 and exon 29 (ex23_ex29del) were detected by long-range PCR. Size analysis of digestion fragments and long-range PCR products was performed by agarose gel electrophoresis. The methods accurately identified mutations or the absence thereof in 16 affected individuals as confirmed by DNA sequencing. Fifteen patients had one or two point mutations, and two of these individuals carried the ex23_ex29del in their second allele. This mutation detection and mapping strategy provides a simple and reliable genetic assay to assist in diagnosis of PXE, differential diagnosis of PXE-like conditions, and study of PXE genetics.

  5. Intra-Rater, Inter-Rater and Test-Retest Reliability of an Instrumented Timed Up and Go (iTUG Test in Patients with Parkinson's Disease.

    Directory of Open Access Journals (Sweden)

    Rob C van Lummel

    Full Text Available The "Timed Up and Go" (TUG is a widely used measure of physical functioning in older people and in neurological populations, including Parkinson's Disease. When using an inertial sensor measurement system (instrumented TUG [iTUG], the individual components of the iTUG and the trunk kinematics can be measured separately, which may provide relevant additional information.The aim of this study was to determine intra-rater, inter-rater and test-retest reliability of the iTUG in patients with Parkinson's Disease.Twenty eight PD patients, aged 50 years or older, were included. For the iTUG the DynaPort Hybrid (McRoberts, The Hague, The Netherlands was worn at the lower back. The device measured acceleration and angular velocity in three directions at a rate of 100 samples/s. Patients performed the iTUG five times on two consecutive days. Repeated measurements by the same rater on the same day were used to calculate intra-rater reliability. Repeated measurements by different raters on the same day were used to calculate intra-rater and inter-rater reliability. Repeated measurements by the same rater on different days were used to calculate test-retest reliability.Nineteen ICC values (15% were ≥ 0.9 which is considered as excellent reliability. Sixty four ICC values (49% were ≥ 0.70 and < 0.90 which is considered as good reliability. Thirty one ICC values (24% were ≥ 0.50 and < 0.70, indicating moderate reliability. Sixteen ICC values (12% were ≥ 0.30 and < 0.50 indicating poor reliability. Two ICT values (2% were < 0.30 indicating very poor reliability.In conclusion, in patients with Parkinson's disease the intra-rater, inter-rater, and test-retest reliability of the individual components of the instrumented TUG (iTUG was excellent to good for total duration and for turning durations, and good to low for the sub durations and for the kinematics of the SiSt and StSi. The results of this fully automated analysis of instrumented TUG movements

  6. Intra-Rater, Inter-Rater and Test-Retest Reliability of an Instrumented Timed Up and Go (iTUG) Test in Patients with Parkinson's Disease.

    Science.gov (United States)

    van Lummel, Rob C; Walgaard, Stefan; Hobert, Markus A; Maetzler, Walter; van Dieën, Jaap H; Galindo-Garre, Francisca; Terwee, Caroline B

    2016-01-01

    The "Timed Up and Go" (TUG) is a widely used measure of physical functioning in older people and in neurological populations, including Parkinson's Disease. When using an inertial sensor measurement system (instrumented TUG [iTUG]), the individual components of the iTUG and the trunk kinematics can be measured separately, which may provide relevant additional information. The aim of this study was to determine intra-rater, inter-rater and test-retest reliability of the iTUG in patients with Parkinson's Disease. Twenty eight PD patients, aged 50 years or older, were included. For the iTUG the DynaPort Hybrid (McRoberts, The Hague, The Netherlands) was worn at the lower back. The device measured acceleration and angular velocity in three directions at a rate of 100 samples/s. Patients performed the iTUG five times on two consecutive days. Repeated measurements by the same rater on the same day were used to calculate intra-rater reliability. Repeated measurements by different raters on the same day were used to calculate intra-rater and inter-rater reliability. Repeated measurements by the same rater on different days were used to calculate test-retest reliability. Nineteen ICC values (15%) were ≥ 0.9 which is considered as excellent reliability. Sixty four ICC values (49%) were ≥ 0.70 and < 0.90 which is considered as good reliability. Thirty one ICC values (24%) were ≥ 0.50 and < 0.70, indicating moderate reliability. Sixteen ICC values (12%) were ≥ 0.30 and < 0.50 indicating poor reliability. Two ICT values (2%) were < 0.30 indicating very poor reliability. In conclusion, in patients with Parkinson's disease the intra-rater, inter-rater, and test-retest reliability of the individual components of the instrumented TUG (iTUG) was excellent to good for total duration and for turning durations, and good to low for the sub durations and for the kinematics of the SiSt and StSi. The results of this fully automated analysis of instrumented TUG movements demonstrate

  7. Assessing Reliability of Two Versions of Vocabulary Levels Tests in Iranian Context

    Science.gov (United States)

    Bayazidi, Aso; Saeb, Fateme

    2017-01-01

    This study examined the equivalence and reliability of the two versions of the Vocabulary Levels Test in an Iranian context. This study was motivated by the fact that the Vocabulary Levels test is increasingly being used in Iran for both research and pedagogical purposes without having been checked for validity and reliability in this context. The…

  8. Reliability and Validity of the Rey Visual Design Learning Test in Primary School Children

    NARCIS (Netherlands)

    Wilhelm, P.

    2004-01-01

    The Rey Visual Design Learning Test (Rey, 1964, in Spreen & Strauss, 1991) assesses immediate memory span, new learning and recognition for non-verbal material. Three studies are presented that focused on the reliability and validity of the RVDLT in primary school children. Test-retest reliability a

  9. Feasibility and reliability of physical fitness tests in older adults with intellectual disability : A pilot study

    NARCIS (Netherlands)

    Hilgenkamp, Thessa I. M.; van Wijck, Ruud; Evenhuis, Heleen M.

    2012-01-01

    Background Physical fitness is relevant for wellbeing and health, but knowledge on the feasibility and reliability of instruments to measure physical fitness for older adults with intellectual disability is lacking. Methods Feasibility and test-retest reliability of a physical fitness test battery (

  10. Feasibility and reliability of physical fitness tests in older adults with intellectual disability : A pilot study

    NARCIS (Netherlands)

    Hilgenkamp, Thessa I. M.; van Wijck, Ruud; Evenhuis, Heleen M.

    Background Physical fitness is relevant for wellbeing and health, but knowledge on the feasibility and reliability of instruments to measure physical fitness for older adults with intellectual disability is lacking. Methods Feasibility and test-retest reliability of a physical fitness test battery

  11. The SCMC test: a reliable monitor for antispermatozoal antibodies.

    Science.gov (United States)

    Franken, D R; Grobler, S; Pretorius, E

    1988-07-01

    Seventeen couples (13%) were selected from a group of 129 infertile patients according to the following criteria: (i) unexplained infertility for 3 years and (ii) greater than 50% shaking spermatozoa during SCMC testing. The couples were tested for sperm antibodies after a complete diagnostic work-up schedule. Post-coital tests were performed during the first menstrual cycle of the wife, followed by SCMC and sperm antibody titre testing. Ten males and seven females were thus treated with 96 mg methylprednisolone. Nine (52%) of the 17 with sperm antibodies achieved a pregnancy. The results of the SCMC test were in all the cases indicative of the actual sperm antibody titre. Reduction of the antibody titre and a decrease in the percentage of shaking spermatozoa as detected by the SCMC test correlated well with the pregnancy rate amongst the patients.

  12. Framework for a Comparative Accelerated Testing Standard for PV Modules: Preprint

    Energy Technology Data Exchange (ETDEWEB)

    Kurtz, S.; Wohlgemuth, J.; Yamamichi, M.; Sample, T.; Miller, D.; Meakin, D.; Monokroussos, C.; TamizhMani, M.; Kempe, M.; Jordan, D.; Bosco, N.; Hacke, P.; Bermudez, V.; Kondo, M.

    2013-08-01

    As the photovoltaic industry has grown, the interest in comparative accelerated testing has also grown. Private test labs offer testing services that apply greater stress than the standard qualification tests as tools for differentiating products and for gaining increased confidence in long-term PV investments. While the value of a single international standard for comparative accelerated testing is widely acknowledged, the development of a consensus is difficult. This paper strives to identify a technical basis for a comparative standard.

  13. Testing the reliability of ice-cream cone model

    Science.gov (United States)

    Pan, Zonghao; Shen, Chenglong; Wang, Chuanbing; Liu, Kai; Xue, Xianghui; Wang, Yuming; Wang, Shui

    2015-04-01

    Coronal Mass Ejections (CME)'s properties are important to not only the physical scene itself but space-weather prediction. Several models (such as cone model, GCS model, and so on) have been raised to get rid of the projection effects within the properties observed by spacecraft. According to SOHO/ LASCO observations, we obtain the 'real' 3D parameters of all the FFHCMEs (front-side full halo Coronal Mass Ejections) within the 24th solar cycle till July 2012, by the ice-cream cone model. Considering that the method to obtain 3D parameters from the CME observations by multi-satellite and multi-angle has higher accuracy, we use the GCS model to obtain the real propagation parameters of these CMEs in 3D space and compare the results with which by ice-cream cone model. Then we could discuss the reliability of the ice-cream cone model.

  14. Reliability and information content of tests with cardioleader in cyclic types of sports

    Science.gov (United States)

    Utkin, V. L.

    1980-01-01

    Tests with cardioleader to control the physical, technical and tactical preparedness of athletes in cyclic types of sports are discussed. Ways of increasing the reliability and information content of the tests were studied.

  15. Specifications, quality control, manufacturing, and testing of accelerator magnets

    CERN Document Server

    Einfeld, D

    2010-01-01

    The performance of the magnets plays an important role in the functioning of an accelerator. Most of the magnets are designed at the accelerator laboratory and built by industry. The link between the laboratory and the manufacturer is the contract containing the Technical Specifications of the magnets. For an overview of the contents of the Technical Specifications, the specifications for the magnets of ALBA (bending, quadrupole, and sextupole) are described in this paper. The basic rules of magnet design are reviewed in Appendix A.

  16. 论语言测试的信度与放度%On Reliability and Validity in Language Testing

    Institute of Scientific and Technical Information of China (English)

    雷雪梅; 宋静

    2007-01-01

    This paper dwells on the two important factors--reliability and validity in language testing: explain the concepts of reliability and validity; factors influencing reliability and validity; possible ways to achieve high reliability and validity; comments on the modern language testing tendency on reliability and validity and authors' own ideas.

  17. Obtaining reliable likelihood ratio tests from simulated likelihood functions

    DEFF Research Database (Denmark)

    Andersen, Laura Mørch

    2014-01-01

    likely to cause misleading test results for the number of draws usually used today. The paper illustrates that increasing the number of draws is a very inefficient solution strategy requiring very large numbers of draws to ensure against misleading test statistics. The main conclusion of this paper...

  18. The validity and reliability of a dynamic neuromuscular stabilization-heel sliding test for core stability.

    Science.gov (United States)

    Cha, Young Joo; Lee, Jae Jin; Kim, Do Hyun; You, Joshua Sung H

    2017-07-21

    Core stabilization plays an important role in the regulation of postural stability. To overcome shortcomings associated with pain and severe core instability during conventional core stabilization tests, we recently developed the dynamic neuromuscular stabilization-based heel sliding (DNS-HS) test. The purpose of this study was to establish the criterion validity and test-retest reliability of the novel DNS-HS test. Twenty young adults with core instability completed both the bilateral straight leg lowering test (BSLLT) and DNS-HS test for the criterion validity study and repeated the DNS-HS test for the test-retest reliability study. Criterion validity was determined by comparing hip joint angle data that were obtained from BSLLT and DNS-HS measures. The test-retest reliability was determined by comparing hip joint angle data. Criterion validity was (ICC2,3) = 0.700 (pcore stability measures. Test-retest reliability was (ICC3,3) = 0.953 (pcore stability measures. Test-retest reliability data suggests that DNS-HS core stability was a reliable test for core stability. Clinically, the DNS-HS test is useful to objectively quantify core instability and allow early detection and evaluation.

  19. Construct Validity and Test Re-Test Reliability of the Forgotten Joint Score.

    Science.gov (United States)

    Thompson, Simon M; Salmon, Lucy J; Webb, Justin M; Pinczewski, Leo A; Roe, Justin P

    2015-11-01

    Consecutive patients undergoing knee arthroplasty completed questionnaires: FJS, Knee Injury and Osteoarthritis Outcome Score (KOOS) and WOMAC Score (mean 39 months after surgery), and were mailed a repeat questionnaire after 4 to 6 weeks. The test-retest reliability was almost perfect for the FJS (ICC = 0.97), and the FJS subdomains (ICC > 0.8). Convergent construct validity of the FJS was correlated with the KOOS Subscores of Quality of Life (0.63, P = 0.001), Symptom (0.33, P = 0.001), Pain (0.68, P = 0.001) and ADL (0.66, P = 0.001) and the Total WOMAC (0.70, P = 0.001). The FJS demonstrates high test-retest reliability and construct validity compared to the Normalised WOMAC and KOOS Subscales. The FJS does not demonstrate the ceiling effect of the WOMAC or KOOS pain scores so may have greater discriminatory ability following TKR. Copyright © 2015 Elsevier Inc. All rights reserved.

  20. STATISTICAL INFERENCE OF WEIBULL DISTRIBUTION FOR TAMPERED FAILURE RATE MODEL IN PROGRESSIVE STRESS ACCELERATED LIFE TESTING

    Institute of Scientific and Technical Information of China (English)

    WANG Ronghua; FEI Heliang

    2004-01-01

    In this note, the tampered failure rate model is generalized from the step-stress accelerated life testing setting to the progressive stress accelerated life testing for the first time. For the parametric setting where the scale parameter satisfying the equation of the inverse power law is Weibull, maximum likelihood estimation is investigated.

  1. Accelerator Stewardship Test Facility Program - Elliptical Twin Cavity for Accelerator Applications

    Energy Technology Data Exchange (ETDEWEB)

    Hutton, Andrew [TJNAF; Areti, Hari [TJNAF

    2015-08-01

    Funding is being requested pursuant to the proposals entitled Elliptical Twin Cavity for Accelerator Applications that was submitted and reviewed through the Portfolio Analysis and Management System (PAMS). The PAMS proposal identifier number is 0000219731. The proposed new type of superconducting cavity, the Elliptical Twin Cavity, is capable of accelerating or decelerating beams in two separate beam pipes. This configuration is particularly effective for high-current, low energy electron beams that will be used for bunched beam cooling of high-energy protons or ions. Having the accelerated beam physically separated from the decelerated beam, but interacting with the same RF mode, means that the low energy beam from the gun can be injected into to the superconducting cavity without bends enabling a small beam emittance to be maintained. A staff engineer who has been working with non-standard complicated cavity structures replaces the senior engineer (in the original budget) who is moving on to be a project leader. This is reflected in a slightly increased engineer time and in reduced costs. The Indirect costs for FY16 are lower than the previous projection. As a result, there is no scope reduction.

  2. [Use and reliability of the Delvo-P-test].

    Science.gov (United States)

    Hässig, M

    2003-02-01

    The Delvo-P-test (Gist-brocades nr, Delft, The Netherlands) is based on biological detection of antibiotics in the milk. According to the procedure of the manufacture the test is suited for bulk milk processing factories. Problems arise when the test is used on milk samples of a single cow. Buffers, cells, bacteria, cell contents, and desinfection without using antibiotics may give false positive and false negative results. An error up to 44.8% was detected on single cow milk samples. The test is well suited for bulk milk, where the processing of milk follows a biological procedure as for cheese. The use on single cow milk samples to prove absence of antibiotics is not recommended.

  3. Reliability of genetic bottleneck tests for detecting recent population declines

    NARCIS (Netherlands)

    Peery, M. Zachariah; Kirby, Rebecca; Reid, Brendan N.; Stoelting, Ricka; Doucet-Beer, Elena; Robinson, Stacie; Vasquez-Carrillo, Catalina; Pauli, Jonathan N.; Palsboll, Per J.

    2012-01-01

    The identification of population bottlenecks is critical in conservation because populations that have experienced significant reductions in abundance are subject to a variety of genetic and demographic processes that can hasten extinction. Genetic bottleneck tests constitute an appealing and popula

  4. Reliability Analysis of Bearing Capacity of Large-Diameter Piles under Osterberg Test

    Directory of Open Access Journals (Sweden)

    Lei Nie

    2013-05-01

    Full Text Available This study gives the reliability analysis of bearing capacity of large-diameter piles under osterberg test. The limit state equation of dimensionless random variables is utilized in the reliability analysis of vertical bearing capacity of large-diameter piles based on Osterberg loading tests. And the reliability index and the resistance partial coefficient under the current specifications are calculated using calibration method. The results show: the reliable index of large-diameter piles is correlated with the load effect ratio and is smaller than the ordinary piles; resistance partial coefficient of 1.53 is proper in design of large-diameter piles.

  5. Integrated Vibration and Acceleration Testing to Reduce Payload Mass, Cost and Mission Risk Project

    Data.gov (United States)

    National Aeronautics and Space Administration — We propose to develop a capability to provide integrated acceleration, vibration, and shock testing using a state-of-the-art centrifuge, allowing for the test of...

  6. Experimental evaluation of the Battelle accelerated test design for the solar array at Mead, Nebraska

    Science.gov (United States)

    Frickland, P. O.; Repar, J.

    1982-01-01

    A previously developed test design for accelerated aging of photovoltaic modules was experimentally evaluated. The studies included a review of relevant field experience, environmental chamber cycling of full size modules, and electrical and physical evaluation of the effects of accelerated aging during and after the tests. The test results indicated that thermally induced fatigue of the interconnects was the primary mode of module failure as measured by normalized power output. No chemical change in the silicone encapsulant was detectable after 360 test cycles.

  7. Experimental evaluation of the Battelle accelerated test design for the solar array at Mead, Nebraska

    Science.gov (United States)

    Frickland, P. O.; Repar, J.

    1982-04-01

    A previously developed test design for accelerated aging of photovoltaic modules was experimentally evaluated. The studies included a review of relevant field experience, environmental chamber cycling of full size modules, and electrical and physical evaluation of the effects of accelerated aging during and after the tests. The test results indicated that thermally induced fatigue of the interconnects was the primary mode of module failure as measured by normalized power output. No chemical change in the silicone encapsulant was detectable after 360 test cycles.

  8. Obtaining reliable Likelihood Ratio tests from simulated likelihood functions

    DEFF Research Database (Denmark)

    Andersen, Laura Mørch

    It is standard practice by researchers and the default option in many statistical programs to base test statistics for mixed models on simulations using asymmetric draws (e.g. Halton draws). This paper shows that when the estimated likelihood functions depend on standard deviations of mixed...

  9. AMSTERDAM-NIJMEGEN EVERYDAY LANGUAGE TEST - CONSTRUCTION, RELIABILITY AND VALIDITY

    NARCIS (Netherlands)

    BLOMERT, L; KEAN, ML; KOSTER, C; SCHOKKER, J

    1994-01-01

    The Amsterdam-Nijmegen Everyday Language Test (ANELT) is designed to measure, first, the level of verbal communicative abilities of aphasic patients and, second, changes in these abilities over time. The level of communicative effectiveness is determined by the adequacy of bringing a message across.

  10. Acceleration Test Method for Failure Prediction of the End Cap Contact Region of Sodium Cooled Fast Reactor Fuel Rod

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Hyung-Kyu; Lee, Young-Ho; Lee, Hyun-Seung; Lee, Kang-Hee [Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of)

    2017-05-15

    This paper reports the results of an acceleration test to predict the contact-induced failure that could occur at the cylinder-to-hole joint for the fuel rod of a sodium-cooled fast reactor (SFR). To incorporate the fuel life of the SFR currently under development at KAERI (around 35,000 h), the acceleration test method of reliability engineering was adopted in this work. A finite element method was used to evaluate the flow-induced vibration frequency and amplitude for the test parameter values. Five specimens were tested. The failure criterion during the life of the SFR fuel was applied. The S-N curve of the HT-9, the material of concern, was used to obtain the acceleration factor. As a result, a test time of 16.5 h was obtained for each specimen. It was concluded that the B{sub 0.004} life would be guaranteed for the SFR fuel rods with 99% confidence if no failure was observed at any of the contact surfaces of the five specimens.

  11. Reliability and normative values of the foot line test: a technique to assess foot posture

    DEFF Research Database (Denmark)

    Brushøj, C; Larsen, Klaus; Nielsen, MB;

    2007-01-01

    STUDY DESIGN: Test-retest reliability. OBJECTIVE: To examine the reliability and report normative values of a novel test, the foot line test (FLT), to describe foot morphology. BACKGROUND: Numerous foot examinations are performed each day, but most existing examination techniques have considerable......). There was no significant association between foot size and FLT values. CONCLUSION: The FLT is a reproducible technique to assess foot posture....

  12. Proving test on the seismic reliability of nuclear power plant: PWR reactor containment vessel

    Energy Technology Data Exchange (ETDEWEB)

    Akiyama, Hiroshi; Yoshikawa, Teiichi; Ohno, Tokue; Yoshikawa, Eiji.

    1989-01-01

    Seismic reliability proving tests of nuclear power plant facilities are carried out by the Nuclear Power Engineering Test Center, using the large-scale, high-performance vibration table of Tadotsu Engineering Laboratory, and sponsored by the Ministry of International Trade and Industry. In 1982, the seismic reliability proving test of a PWR containment vessel was conducted using a test component of reduced scale 1/3.7. As a result of this test, the test component proved to have structural soundness against earthquakes, and at the same time its stable function was proved by leak tests which were carried out before and after the vibration test. In 1983, the detailed analysis and evaluation of these test results were carried out, and the analysis methods for evaluating strength against earthquakes were established. The seismic analysis and evaluation on the actual containment vessel were then performed using these analysis methods, and the safety and reliability of the PWR reactor containment vessel were confirmed.

  13. Reliability of physical examination tests for the diagnosis of knee disorders: Evidence from a systematic review.

    Science.gov (United States)

    Décary, Simon; Ouellet, Philippe; Vendittoli, Pascal-André; Desmeules, François

    2016-12-01

    Clinicians often rely on physical examination tests to guide them in the diagnostic process of knee disorders. However, reliability of these tests is often overlooked and may influence the consistency of results and overall diagnostic validity. Therefore, the objective of this study was to systematically review evidence on the reliability of physical examination tests for the diagnosis of knee disorders. A structured literature search was conducted in databases up to January 2016. Included studies needed to report reliability measures of at least one physical test for any knee disorder. Methodological quality was evaluated using the QAREL checklist. A qualitative synthesis of the evidence was performed. Thirty-three studies were included with a mean QAREL score of 5.5 ± 0.5. Based on low to moderate quality evidence, the Thessaly test for meniscal injuries reached moderate inter-rater reliability (k = 0.54). Based on moderate to excellent quality evidence, the Lachman for anterior cruciate ligament injuries reached moderate to excellent inter-rater reliability (k = 0.42 to 0.81). Based on low to moderate quality evidence, the Tibiofemoral Crepitus, Joint Line and Patellofemoral Pain/Tenderness, Bony Enlargement and Joint Pain on Movement tests for knee osteoarthritis reached fair to excellent inter-rater reliability (k = 0.29 to 0.93). Based on low to moderate quality evidence, the Lateral Glide, Lateral Tilt, Lateral Pull and Quality of Movement tests for patellofemoral pain reached moderate to good inter-rater reliability (k = 0.49 to 0.73). Many physical tests appear to reach good inter-rater reliability, but this is based on low-quality and conflicting evidence. High-quality research is required to evaluate the reliability of knee physical examination tests.

  14. The reliability of two visual motor integration tests used with healthy adults.

    Science.gov (United States)

    Brown, Ted; Chinner, Alexandra; Stagnitti, Karen

    2010-10-01

    ABSTRACT Occupational therapists often assess the visual motor integration (VMI) skills of children, adults, and the elderly, which are parts of the Body Functions and Structures of the International Classification of Functioning, Disability and Health. Objective. As it is imperative that therapists use tests and measures with strong psychometric properties, this study aims to examine the reliability of two VMI tests used with adults. Method. Sixty-one healthy adults, 18 males and 43 females, with an average age of 31.82 years, completed the Developmental Test of Visual Motor Integration (DTVMI) and the Full Range Test of Visual Motor Integration (FRTVMI). The Cronbach's alpha coefficient was used to examine the tests' internal consistency, while the Spearman's rho correlation was used to evaluate the test-retest reliability, intrarater reliability, and interrater reliability of the two VMI tests. Results. The Cronbach's alpha coefficient for the DTVMI and FRTVMI was 0.66 and 0.80, respectively. The test-retest reliability coefficient was 0.77 (p VMI tests appear to exhibit reasonable levels of reliability and are recommended for use with adults and the elderly.

  15. First reliability test of a surface micromachined microengine using SHiMMeR

    Energy Technology Data Exchange (ETDEWEB)

    Tanner, D.M.; Smith, N.F.; Bowman, D.J. [and others

    1997-08-01

    The first-ever reliability stress test on surface micromachined microengines developed at Sandia National Laboratories (SNL) has been completed. We stressed 41 microengines at 36,000 RPM and inspected the functionality at 60 RPM. We have observed an infant mortality region, a region of low failure rate (useful life), and no signs of wearout in the data. The reliability data are presented and interpreted using standard reliability methods. Failure analysis results on the stressed microengines are presented. In our effort to study the reliability of MEMS, we need to observe the failures of large numbers of parts to determine the failure modes. To facilitate testing of large numbers of micromachines. The Sandia High Volume Measurement of Micromachine Reliability (SHiMMeR) system has computer controlled positioning and the capability to inspect moving parts. The development of this parallel testing system is discussed in detail.

  16. Reliability of "Modified timed up and go" test in children with cerebral palsy.

    Science.gov (United States)

    Dhote, Sanjivani N; Khatri, Prema A; Ganvir, Suvarna S

    2012-05-01

    Timed up and go (TUG) is a quick test used in clinical practice as an outcome measure to assess functional ambulatory mobility or dynamic balance in adults. However, little information is available on TUG test used in cerebral palsy. Hence, the purpose of our study was to assess the intra-rater reliability of TUG test in cerebral palsy children. To assess within-session and test-retest reliability after 1 week of TUG test in cerebral palsy children. It was an a cross-sectional observational study conducted in a neurorehabilitation unit, with 30 cerebral palsy children of 4-12 years, within Gross Motor Function Classification System (GMFCS) level I, II, III, and with an IQ ≥50.The sampling technique used was purposive sampling excluding children with cognitive deficit. Subjects performed TUG on three occasions - Initial assessment (time 1), 30 min after initial assessment (time 2), and 1 week after initial assessment (time 3). Three trails were conducted for each of the three occasions. The mean score of three trials was documented as the final score. Within-session and test-retest reliability were analyzed using scores of time 1 and 2, and time 1 and 3, respectively. The documented data were analyzed for within-session and test-retest reliability after 1 week of TUG test by using intraclass correlation coefficient (ICC). Reliability of TUG test was high, with ICC of 0.99 for within-session reliability and 0.99 for test-retest reliability. Intra-rater reliability of TUG test in cerebral palsy children was found to be high.

  17. Reliability of "Modified timed up and go" test in children with cerebral palsy

    Directory of Open Access Journals (Sweden)

    Sanjivani N Dhote

    2012-01-01

    Full Text Available Background: Timed up and go (TUG is a quick test used in clinical practice as an outcome measure to assess functional ambulatory mobility or dynamic balance in adults. However, little information is available on TUG test used in cerebral palsy. Hence, the purpose of our study was to assess the intra-rater reliability of TUG test in cerebral palsy children. Aim and Objective: To assess within-session and test-retest reliability after 1 week of TUG test in cerebral palsy children. Setting and Design: It was an a cross-sectional observational study conducted in a neurorehabilitation unit, with 30 cerebral palsy children of 4-12 years, within Gross Motor Function Classification System (GMFCS level I, II, III, and with an IQ ≥50.The sampling technique used was purposive sampling excluding children with cognitive deficit. Materials and Methods: Subjects performed TUG on three occasions - Initial assessment (time 1, 30 min after initial assessment (time 2, and 1 week after initial assessment (time 3. Three trails were conducted for each of the three occasions. The mean score of three trials was documented as the final score. Within-session and test-retest reliability were analyzed using scores of time 1 and 2, and time 1 and 3, respectively. Statistical Analysis: The documented data were analyzed for within-session and test-retest reliability after 1 week of TUG test by using intraclass correlation coefficient (ICC. Results: Reliability of TUG test was high, with ICC of 0.99 for within-session reliability and 0.99 for test-retest reliability. Conclusion: Intra-rater reliability of TUG test in cerebral palsy children was found to be high.

  18. Validity and reliability of a new test for Turkish-speaking aphasic patients: Ege Aphasia Test.

    Science.gov (United States)

    Calis, Funda Atamaz; On, Arzu Yagiz; Durmaz, Berrin

    2013-01-01

    Due to the fact that the phonetic, morphological and syntactic structures of the Turkish language differ significantly from other European languages, the translated forms of the currently available aphasia assessment batteries are not adequate for Turkish-speaking aphasic patients. The aim of this study was to assess the validity and reliability of the Ege Aphasia Test that we have developed. The test, which includes the 8 subtests of praxia, spontaneous language, auditory and verbal comprehension, repetition, naming, reading, writing and calculating, was applied into 100 aphasic patients, 40 dysarthric patients and 40 healthy subjects. All test-retest intra-class correlation coefficients were found to be excellent (ICC = 0.99). The Cronbach's coefficients ranged from 0.71 to 0.91. All the subtests showed significantly greater scores in aphasic patients (p language, which is spoken mainly in Turkey and in the surrounding regions. We believe that this study will pioneer the development of aphasia rehabilitation in these countries and contribute to future studies.

  19. Reliability of ultrasound thickness measurement of the abdominal muscles during clinical isometric endurance tests.

    Science.gov (United States)

    ShahAli, Shabnam; Arab, Amir Massoud; Talebian, Saeed; Ebrahimi, Esmaeil; Bahmani, Andia; Karimi, Noureddin; Nabavi, Hoda

    2015-07-01

    The study was designed to evaluate the intra-examiner reliability of ultrasound (US) thickness measurement of abdominal muscles activity when supine lying and during two isometric endurance tests in subjects with and without Low back pain (LBP). A total of 19 women (9 with LBP, 10 without LBP) participated in the study. Within-day reliability of the US thickness measurements at supine lying and the two isometric endurance tests were assessed in all subjects. The intra-class correlation coefficient (ICC) was used to assess the relative reliability of thickness measurement. The standard error of measurement (SEM), minimal detectable change (MDC) and the coefficient of variation (CV) were used to evaluate the absolute reliability. Results indicated high ICC scores (0.73-0.99) and also small SEM and MDC scores for within-day reliability assessment. The Bland-Altman plots of agreement in US measurement of the abdominal muscles during the two isometric endurance tests demonstrated that 95% of the observations fall between the limits of agreement for test and retest measurements. Together the results indicate high intra-tester reliability for the US measurement of the thickness of abdominal muscles in all the positions tested. According to the study's findings, US imaging can be used as a reliable method for assessment of abdominal muscles activity in supine lying and the two isometric endurance tests employed, in participants with and without LBP.

  20. The new features of the ExaMe evaluation system and reliability of its fixed tests.

    Science.gov (United States)

    Martinková, P; Zvára, K; Zvárová, J; Zvára, K

    2006-01-01

    The ExaMe system for the evaluation of targeted knowledge has been in development since 1998. The new features of the ExaMe system are introduced in this paper. Especially, the new three-layer architecture is described. Besides the system itself, the properties of fixed tests in the ExaMe system are studied. In special detail, the reliability of the fixed tests is discussed. The theory background is explained and some limitations of the reliability are pointed out. Three characteristics used for estimation of reliability of educational tests are discussed: Cronbach's alpha, standardized item alpha and split half coefficient. The relation between these characteristics and reliability and between characteristics themselves is investigated. In more detail, the properties of Cronbach's alpha, the characteristics mostly used for the estimation of reliability, are discussed. A confidence interval is introduced for the characteristics. Since 2000, the serviceability of the ExaMe evaluation system as the supporting evaluation tool has been repeatedly shown at the courses of Ph.D. studies in biomedical informatics at Charles University in Prague. The ExaMe system also opens new possibilities for self-evaluation and distance learning, especially when connected with electronic books on the Internet. The estimation of reliability of tests contains some limitations. Keeping them in mind, we can still get some information about the quality of certain educational tests. Therefore, the estimation of reliability of the fixed tests is implemented in the ExaMe system.

  1. Digital System Reliability Test for the Evaluation of safety Critical Software of Digital Reactor Protection System

    Directory of Open Access Journals (Sweden)

    Hyun-Kook Shin

    2006-08-01

    Full Text Available A new Digital Reactor Protection System (DRPS based on VME bus Single Board Computer has been developed by KOPEC to prevent software Common Mode Failure(CMF inside digital system. The new DRPS has been proved to be an effective digital safety system to prevent CMF by Defense-in-Depth and Diversity (DID&D analysis. However, for practical use in Nuclear Power Plants, the performance test and the reliability test are essential for the digital system qualification. In this study, a single channel of DRPS prototype has been manufactured for the evaluation of DRPS capabilities. The integrated functional tests are performed and the system reliability is analyzed and tested. The results of reliability test show that the application software of DRPS has a very high reliability compared with the analog reactor protection systems.

  2. Coefficient Alpha as an Estimate of Test Reliability under Violation of Two Assumptions.

    Science.gov (United States)

    Zimmerman, Donald W.; And Others

    1993-01-01

    Coefficient alpha was examined through computer simulation as an estimate of test reliability under violation of two assumptions. Coefficient alpha underestimated reliability under violation of the assumption of essential tau-equivalence of subtest scores and overestimated it under violation of the assumption of uncorrelated subtest error scores.…

  3. Estimation of Internal Consistency Reliability When Test Parts Vary in Effective Length.

    Science.gov (United States)

    Feldt, Leonard S.; Charter, Richard A.

    2003-01-01

    Evaluating a test's reliability often requires dividing it into 3 or more unequal parts, which causes violation of the tau equivalence assumption of Cronbach's alpha. This article presents a criterion for abandoning alpha and an approach for computing a more appropriate estimate of reliability, the Gilmer-Feldt coefficient. (Author)

  4. Reliability and accuracy of Cooper's test in male long distance runners

    Directory of Open Access Journals (Sweden)

    J.R. Alvero-Cruz

    2017-06-01

    Conclusions: All together, our results may confirm a good accuracy and reliability of Cooper's test in amateur long distance runners. Also, improvements or impairment lower than 52.2 m must not be associated with exercise training or retraining, since they are below the values of intra-subject reliability.

  5. Test-Retest Reliability of Dual-Task Outcome Measures in People With Parkinson Disease

    NARCIS (Netherlands)

    Strouwen, C.; Molenaar, E.A.; Keus, S.H.; Munks, L.; Bloem, B.R.; Nieuwboer, A.

    2016-01-01

    BACKGROUND: Dual-task (DT) training is gaining ground as a physical therapy intervention in people with Parkinson disease (PD). Future studies evaluating the effect of such interventions need reliable outcome measures. To date, the test-retest reliability of DT measures in patients with PD remains l

  6. Interrater Reliability of the 6-Minute Walk Test in Women With Hip Fracture

    DEFF Research Database (Denmark)

    Overgaard, Jan; Larsen, Camilla Marie; Holtze, Steffen

    2017-01-01

    BACKGROUND AND PURPOSE: The 6-minute walk test (6MWT) is widely used as a clinical outcome measure. However, the reliability of the 6MWT is unknown in individuals who have recently experienced a hip fracture. The aim of this study was to evaluate the relative and absolute interrater reliability o...

  7. DETERMINING THE RELIABILITY AND VALIDITY OF A MODIFICATION OF THE CET 4 WRITING TEST

    Institute of Scientific and Technical Information of China (English)

    1997-01-01

    The CET 4 writing test is widely used in China,but whether it is a more reliable and valid test ofwriting for CET 4 than other methods of evaluation is still not clear.The purpose of this study was to examine the reliability and the validity of a modification of this test.In carrying out the study,a total of 60 Band 4 students in Zhejiang University took the modified test,aCET 4 test and a First Certificate Practice Test.The results of this study demonstrate that themodified version is a significantly more reliable and valid writing test than the present CET 4 writingtest.These results suggest that the CET 4 writing test needs modification.

  8. The Reliability of Strength Tests Performed In Elevated Shoulder Positions Using a Handheld Dynamometer.

    Science.gov (United States)

    McLaine, Sally J; Ginn, Karen A; Kitic, Cecilia M; Fell, James W; Bird, Marie-Louise

    2016-06-06

    The reliable measurement of shoulder strength is important when assessing athletes involved in overhead activities. Swimmers' shoulders are subject to repetitive humeral elevation and consequently have a high risk of developing movement-control issues and pain. Shoulder-strength tests performed in positions of elevation assist with the detection of strength deficits that may affect injury and performance. The reliability of isometric strength tests performed in positions of humeral elevation without manual stabilization, which is a typical clinical scenario, has not been established. To establish the relative and absolute intrarater reliability of shoulder-strength tests functional to swimming in 3 body positions commonly used in the clinical setting. Repeated-measures reliability study. Research laboratory. 15 university students and staff (mean ± SD age 24 ± 8.2 y). Isometric shoulder-strength tests were performed in positions of humeral elevation (flexion and extension in 140° abduction in the scapular plane, internal and external rotation in 90° abduction) on subjects without shoulder pain in supine, prone, and sitting. Subjects were tested by 1 examiner with a handheld dynamometer and retested after 48 h. Relative reliability (ICC3,1) values with 95% CI. Absolute reliability was reported by minimal detectable change (MDC). Good to excellent intrarater reliability was found for all shoulder-strength tests (ICC .87-.99). Intrarater reliability was not affected by body position. MDC% was rotation strength tests performed in humeral elevation demonstrated excellent to good intrarater reliability regardless of body position. A strength change of more than 15% in any position can be considered meaningful.

  9. Testing the stability and reliability of starspot modelling.

    Science.gov (United States)

    Kovari, Zs.; Bartus, J.

    1997-07-01

    Since the mid 70's different starspot modelling techniques have been used to describe the observed spot variability on active stars. Spot positions and temperatures are calculated by application of surface integration techniques or solution of analytic equations on observed photometric data. Artificial spotted light curves were generated, by use of the analytic expressions of Budding (1977Ap&SS..48..207B), to test how the different constraints like the intrinsic scatter of the observed data or the angle of inclination affects the spot solutions. Counteractions between the different parameters like inclination, latitude and spot size were also investigated. The results of re-modelling the generated data were scrutinized statistically. It was found, that (1) 0.002-0.005mag of photometric accuracy is required to recover geometrical spot parameters within an acceptable error box; (2) even a 0.03-0.05mag error in unspotted brightness substantially affects the recovery of the original spot distribution; (3) especially at low inclination, under- or overestimation of inclination by 10° leads to an important systematic error in spot latitude and size; (4) when the angle of inclination i<~20° photometric spot modelling is unable to provide satisfactory information on spot location and size.

  10. Reliability of health-related physical fitness tests in adolescents: the MOVE Program.

    Science.gov (United States)

    Vanhelst, Jérémy; Béghin, Laurent; Fardy, Paul S; Ulmer, Zekya; Czaplicki, Grégory

    2016-03-01

    The aim was to examine the reliability of health-related physical fitness tests that were used in a French health promotion program 'Move…A priority for your health'. Participants were 174 French youth (88 children and 86 adolescents) aged 8·2-16·2 years. Aerobic fitness, muscular strength, speed and flexibility were tested using 20-m shuttle run test, ½ mile run test, basketball throw, standing long jump, shoulder stretch and 20/30/50-m sprint tests. Reliability was calculated for the basketball throw, standing long jump, shoulder stretch and sprint tests. The tests were performed two times, 1 week apart on the same day of the week. Reliability was examined with intraclass correlation coefficients (ICCs) and Bland-Altman analysis. With the exception of the ½ mile run test, which resulted in moderate agreement (0·66), all tests had high reliability. ICCs were 0·97, 0·93, 0·91 and 0·93 for the sprint test, basketball throw, shoulder stretch and the standing long jump, respectively. The differences obtained between the first and the second trial were non-significant. Results from this study indicate that the BOUGE health-related physical fitness battery, administrated by physical education teachers, was reliable for measuring health-related components of fitness in children and adolescents in a school setting.

  11. Assessing Reliability of Two Versions of Vocabulary Levels Tests in Iranian Context

    Directory of Open Access Journals (Sweden)

    Aso Bayazidi

    2017-02-01

    Full Text Available This study examined the equivalence and reliability of the two versions of the Vocabulary Levels Test in an Iranian context. This study was motivated by the fact that the Vocabulary Levels test is increasingly being used in Iran for both research and pedagogical purposes without having been checked for validity and reliability in this context. The equivalence and reliability of the two versions of the test were examined through the parallel-form approach to reliability in Classical True Score theory. Seventy-five intermediate learners of English as a foreign language at the Iran Language Institute took the two versions of the test with one week interval between the two administrations in a counterbalanced fashion. To examine the equivalence of the two versions, the means and variances of the scores obtained for the two tests were compared using paired-sample t-test and one-way ANOVA, respectively. The results of the analyses indicated that the difference between the means of the two versions was significant, and the two versions cannot be considered as parallel forms. To assess the reliability of the two versions, the correlation between the scores obtained from them was estimated using Pearson Product Moment correlation. The results of the analyses showed that the two versions are highly correlated and are reliable tests. It is concluded that the two versions should not be treated as equivalent in longitudinal and gain score studies.

  12. Reliability of static and dynamic quantitative sensory testing in patients with painful chronic pancreatitis.

    NARCIS (Netherlands)

    Olesen, S.S.; Goor, H. van; Bouwense, S.A.W.; Wilder-Smith, O.H.G.; Drewes, A.M.

    2012-01-01

    BACKGROUND AND OBJECTIVES: Quantitative sensory testing (QST) has proven to be an important instrument to characterize mechanisms underlying somatic and neuropathic pain disorders. However, its reliability has not previously been established in patients with visceral pain. We investigated the

  13. Test–re-test reliability and inter-rater reliability of a digital pelvic inclinometer in young, healthy males and females

    Directory of Open Access Journals (Sweden)

    Chris Beardsley

    2016-03-01

    Full Text Available Objective. The purpose of this study was to investigate the reliability of a digital pelvic inclinometer (DPI for measuring sagittal plane pelvic tilt in 18 young, healthy males and females. Method. The inter-rater reliability and test–re-test reliabilities of the DPI for measuring pelvic tilt in standing on both the right and left sides of the pelvis were measured by two raters carrying out two rating sessions of the same subjects, three weeks apart. Results. For measuring pelvic tilt, inter-rater reliability was designated as good on both sides (ICC = 0.81–0.88, test–re-test reliability within a single rating session was designated as good on both sides (ICC = 0.88–0.95, and test–re-test reliability between two rating sessions was designated as moderate on the left side (ICC = 0.65 and good on the right side (ICC = 0.85. Conclusion. Inter-rater reliability and test–re-test reliability within a single rating session of the DPI in measuring pelvic tilt were both good, while test–re-test reliability between rating sessions was moderate-to-good. Caution is required regarding the interpretation of the test–re-test reliability within a single rating session, as the raters were not blinded. Further research is required to establish validity.

  14. Test-retest reliability and age-related characteristics of the ocular and cervical vestibular evoked myogenic potential tests.

    Science.gov (United States)

    Nguyen, Kimanh D; Welgampola, Miriam S; Carey, John P

    2010-07-01

    To determine the test-retest reliability and age-related trends of the cervical and ocular vestibular evoked myogenic potential (cVEMP and oVEMP, respectively) responses to air-conducted sound and bone-conducted vibration stimulation. Prospective study. Tertiary referral center. Fifty-three healthy adults with no hearing or vestibular deficits. All subjects underwent cVEMP and oVEMP testing in response to sounds (0.1-ms clicks and 500-Hz tone bursts) and vibration (midline forehead taps at the hairline, Fz, with a reflex hammer and a Brüel & Kjaer Mini-Shaker Type 4810). Twelve subjects underwent an additional testing session that was conducted at a mean of 10 weeks after the first one. Test-retest reliability for VEMP response parameters (latency, peak-to-peak amplitude, and asymmetry ratio) were assessed using the intraclass correlation coefficient (ICC). : oVEMP amplitudes had excellent test-retest reliability (ICC > 0.75) for all 4 stimuli; cVEMP amplitudes had excellent reliability for hammer taps and fair-to-good reliability for other stimuli. oVEMP asymmetry ratios had excellent reliability for clicks and fair-to-good reliability (ICC = 0.4-0.75) for other stimuli; cVEMP asymmetry ratios had fair-to-good reliability for clicks and hammer taps. Older subjects (>50 years old) were found to have significantly decreased cVEMP amplitudes in response to clicks, tones, and taps with a Mini-Shaker and significantly decreased oVEMP amplitudes in response to clicks, tones, and taps with a reflex hammer. No age-related changes were found for latencies or asymmetry ratios. Overall, oVEMP response parameters demonstrated better test-retest reliability than cVEMP response parameters, but oVEMPs and cVEMPs had similar age-related changes.

  15. Maintenance and improvement of interobserver reliability of osteopathic palpatory tests over a 4-month period.

    Science.gov (United States)

    Degenhardt, Brian F; Johnson, Jane C; Snider, Karen T; Snider, Eric J

    2010-10-01

    Few studies have shown that diagnostic palpation is reliable. No studies have shown that the reliability of diagnostic palpatory skills can be maintained and improved over time. To investigate whether the reliability of selected palpatory tests used to identify lumbar somatic dysfunction was maintained during a 4-month period as part of a clinical observational study. Participants with low back pain and participants without low back pain, recruited from a rural Midwestern community, were examined during 6 separate sessions over a 4-month period. During each data collection session, two blinded examiners, who had previously completed comprehensive consensus training, evaluated the lumbar region with four tests: static segmental positional asymmetry of the transverse processes in the horizontal plane, tissue texture abnormalities, resistance to anterior springing on the spinous processes, and tenderness induced by pressure on the spinous processes. Detailed protocols for each test were defined during a previous comprehensive consensus training period and were not revised during the current study. To verify that established interobserver reliability was maintained throughout the clinical study, quality control sampling was performed on all data. When findings were inconsistent between the two examiners, focused consensus training was performed as a means of recalibration to understand why assessments were inconsistent. Interobserver reliability for determining the presence or absence of somatic dysfunction was assessed using kappa coefficients. The study enrolled 64 participants, and 14 to 33 participants were examined per session. All four tests had acceptable interobserver reliability by the final data collection session. The test for static segmental positional asymmetry of the transverse processes in the horizontal plane had moderate to substantial reliability in all 6 sessions. The test for tissue texture abnormalities had moderate reliability in 5 of the 6

  16. Study Of Ceramic-Polymer Composites Reliability Based On The Bending Strength Test

    Directory of Open Access Journals (Sweden)

    Walczak Agata

    2015-11-01

    Full Text Available In this paper the reliability assessment of structural reliability of the selected light-cured dental composites based on the biaxial flexural strength test results has been presented. A two-parameter Weibull distribution was applied as a reliability model in order to estimate probability of strength maintenance in the analysed population. Weibull distribution parameters were interpreted as a characteristic material strength (scale parameter and structural reliability parameter in terms of ability to maintain strength by each of specimen from the general population (shape parameter. 20 composite specimens underwent strength tests, including 2 “flow” type composites and 2 standard composites (with typical filler content. “Flow” type composites were characterized with lower characteristic strength and higher structural reliability comparing to other studied composites.

  17. A Pilot Study of Visual-Motor Developmental Inter-Test Reliability: The Beery Developmental Test of Visual Motor Integration and the Bender Visual Motor Gestalt Test.

    Science.gov (United States)

    Porter, Gary L.; Binder, Dorothy M.

    1981-01-01

    To determine the intertest reliability of the Beery Developmental Test of Visual Motor Integration (VMI) and the Bender Visual Motor Gestalt Test (BGT), 64 six to nine year olds were administered both tests.

  18. A comparative study of an accelerated life-test model and a toxicokinetics-based model for the analysis of Porcellio scaber survival data.

    Science.gov (United States)

    Ren, Shijin

    2004-01-01

    Statistical models have long been used for reliability analysis and risk assessment. In the present study, an accelerated life-test model was used to analyze a set of dose-time-response data obtained with the terrestrial isopod Porcellio scaber. Survival data were experimentally obtained by exposing P. scaber to diazinon (a nonpersistent insecticide) at six concentrations between 2 and 11.31 microg/g (toxicant/soil). Survival data are presented on a weekly basis. The accelerated life-test model assumed a log-normal distribution and constant variance across all diazinon concentrations. Model parameters were obtained by maximum likelihood estimation. The accelerated life-test model was compared to a toxicokinetics-based model reported in the literature. Survival predictions made by both models were compared with the observed data. Both the accelerated life-test model and the toxicokinetics-based model underestimated toxicity at a diazinon concentration of 8 microg/g. Overall, however, the accelerated life-test model outperformed the toxicokinetics-based model, with survival predictions closer to the observed data in most cases and a stronger correlation between predicted and observed survivals. However, as a statistical model, the accelerated life-test model did not reveal mechanistic information, and only statistical and distributional interpretations of its model parameters could be made.

  19. The reliability of aerobic capacity (VO2max) testing in adolescent girls.

    Science.gov (United States)

    Pivarnik, J M; Dwyer, M C; Lauderdale, M A

    1996-09-01

    Despite the fact that our subjects were naive regarding the test procedures, it appears that aerobic fitness testing using an incremental treadmill protocol is extremely reliable in adolescent girls. In addition, day-to-day variability of VO2max in our subjects averaged less than 5%, which is similar to results obtained with adults (Katch, Sady, & Freedson, 1982). Finally, it was most encouraging to find that a single VO2max test trial resulted in high reliability coefficients. This finding should provide a great deal of confidence to investigators who are performing aerobic fitness tests on large numbers of subjects where multiple testing is neither practical nor cost-effective.

  20. Reliability of Health-Related Physical Fitness Tests among Colombian Children and Adolescents: The FUPRECOL Study

    OpenAIRE

    Robinson Ramírez-Vélez; Diogo Rodrigues-Bezerra; Jorge Enrique Correa-Bautista; Mikel Izquierdo; Felipe Lobelo

    2015-01-01

    Substantial evidence indicates that youth physical fitness levels are an important marker of lifestyle and cardio-metabolic health profiles and predict future risk of chronic diseases. The reliability physical fitness tests have not been explored in Latino-American youth population. This study's aim was to examine the reliability of health-related physical fitness tests that were used in the Colombian health promotion "Fuprecol study". Participants were 229 Colombian youth (boys n = 124 and g...

  1. Reliability of “Modified timed up and go” test in children with cerebral palsy

    Science.gov (United States)

    Dhote, Sanjivani N.; Khatri, Prema A.; Ganvir, Suvarna S.

    2012-01-01

    Background: Timed up and go (TUG) is a quick test used in clinical practice as an outcome measure to assess functional ambulatory mobility or dynamic balance in adults. However, little information is available on TUG test used in cerebral palsy. Hence, the purpose of our study was to assess the intra-rater reliability of TUG test in cerebral palsy children. Aim and Objective: To assess within–session and test-retest reliability after 1 week of TUG test in cerebral palsy children. Setting and Design: It was an a cross-sectional observational study conducted in a neurorehabilitation unit, with 30 cerebral palsy children of 4–12 years, within Gross Motor Function Classification System (GMFCS) level I, II, III, and with an IQ ≥50.The sampling technique used was purposive sampling excluding children with cognitive deficit. Materials and Methods: Subjects performed TUG on three occasions – Initial assessment (time 1), 30 min after initial assessment (time 2), and 1 week after initial assessment (time 3). Three trails were conducted for each of the three occasions. The mean score of three trials was documented as the final score. Within-session and test–retest reliability were analyzed using scores of time 1 and 2, and time 1 and 3, respectively. Statistical Analysis: The documented data were analyzed for within-session and test–retest reliability after 1 week of TUG test by using intraclass correlation coefficient (ICC). Results: Reliability of TUG test was high, with ICC of 0.99 for within-session reliability and 0.99 for test–retest reliability. Conclusion: Intra-rater reliability of TUG test in cerebral palsy children was found to be high. PMID:23248683

  2. Inter- and intra-observer reliability of clinical movement-control tests for marines

    Directory of Open Access Journals (Sweden)

    Monnier Andreas

    2012-12-01

    Full Text Available Abstract Background Musculoskeletal disorders particularly in the back and lower extremities are common among marines. Here, movement-control tests are considered clinically useful for screening and follow-up evaluation. However, few studies have addressed the reliability of clinical tests, and no such published data exists for marines. The present aim was therefore to determine the inter- and intra-observer reliability of clinically convenient tests emphasizing movement control of the back and hip among marines. A secondary aim was to investigate the sensitivity and specificity of these clinical tests for discriminating musculoskeletal pain disorders in this group of military personnel. Methods This inter- and intra-observer reliability study used a test-retest approach with six standardized clinical tests focusing on movement control for back and hip. Thirty-three marines (age 28.7 yrs, SD 5.9 on active duty volunteered and were recruited. They followed an in-vivo observation test procedure that covered both low- and high-load (threshold tasks relevant for marines on operational duty. Two independent observers simultaneously rated performance as “correct” or “incorrect” following a standardized assessment protocol. Re-testing followed 7–10 days thereafter. Reliability was analysed using kappa (κ coefficients, while discriminative power of the best-fitting tests for back- and lower-extremity pain was assessed using a multiple-variable regression model. Results Inter-observer reliability for the six tests was moderate to almost perfect with κ-coefficients ranging between 0.56-0.95. Three tests reached almost perfect inter-observer reliability with mean κ-coefficients > 0.81. However, intra-observer reliability was fair-to-moderate with mean κ-coefficients between 0.22-0.58. Three tests achieved moderate intra-observer reliability with κ-coefficients > 0.41. Combinations of one low- and one high-threshold test best discriminated

  3. The four square step test in children with Down syndrome: Reliability and concurrent validity

    Directory of Open Access Journals (Sweden)

    Ajai Verma

    2014-01-01

    Full Text Available Purpose: To estimate test-retest reliability, inter-rater reliability and validation of a method for measuring balance by stepping over four squares, four square step test (FSST in children with Down syndrome (DS. Methods: A sample of 13 children with DS was recruited for the cross-sectional study. They were asked to perform FSST and the time taken was noted. For estimating test-retest reliability, FSST was done by principal investigator twice and Inter-rater reliability was assessed by principal investigator and second investigator with an interval of 7 days. FRT was used as the criterion dynamic balance measure to validate FSST. The data was tabulated and analysed statistically. Results: The test-retest reliability and inter-rater reliability of FSST are ICC (1,1 = 0.70 (0.64-0.90 and ICC (2,1 = 0.78 (0.62-0.91 respectively. The Bland-Altman limits of agreement were also satisfied. Concurrent validity between FRT and FSST with Spearman′s ρ = −0.58 (−0.86 to −0.13. Conclusion: FSST has moderate to good concurrent validity and good reliability among the children with Down syndrome.

  4. Test-Retest Reliability and Physiological Responses Associated with the Steep Ramp Anaerobic Test in Patients with COPD

    Directory of Open Access Journals (Sweden)

    Robyn L. Chura

    2012-01-01

    Full Text Available The Steep Ramp Anaerobic Test (SRAT was developed as a clinical test of anaerobic leg muscle function for use in determining anaerobic power and in prescribing high-intensity interval exercise in patients with chronic heart failure and Chronic Obstructive Pulmonary Disease (COPD; however, neither the test-retest reliability nor the physiological qualities of this test have been reported. We therefore, assessed test-retest reliability of the SRAT and the physiological characteristics associated with the test in patients with COPD. 11 COPD patients (mean FEV1 43% predicted performed a cardiopulmonary exercise test (CPET on Day 1, and an SRAT and a 30-second Wingate anaerobic test (WAT on each of Days 2 and 3. The SRAT showed a high degree of test-retest reliability (ICC=0.99; CV=3.8%, and bias 4.5 W, error −15.3–24.4 W. Power output on the SRAT was 157 W compared to 66 W on the CPET and 231 W on the WAT. Despite the differences in workload, patients exhibited similar metabolic and ventilatory responses between the three tests. Measures of ventilatory constraint correlated more strongly with the CPET than the WAT; however, physiological variables correlated more strongly with the WAT. The SRAT is a highly reliable test that better reflects physiological performance on a WAT power test despite a similar level of ventilatory constraint compared to CPET.

  5. Measuring test mass acceleration noise in space-based gravitational wave astronomy

    CERN Document Server

    Congedo, Giuseppe

    2014-01-01

    The basic constituent of interferometric gravitational wave detectors -- the test mass to test mass interferometric link -- behaves as a differential dynamometer measuring effective differential forces, comprising an integrated measure of gravity curvature, inertial effects, as well as non-gravitational spurious forces. This last contribution is going to be characterised by the LISA Pathfinder mission, a technology precursor of future space-borne detectors like eLISA. Changing the perspective from displacement to acceleration can benefit the data analysis of LISA Pathfinder and future detectors. The response in differential acceleration to gravitational waves is derived for a space-based detector's interferometric link. The acceleration formalism can also be integrated into time delay interferometry by building up the unequal-arm Michelson differential acceleration combination. The differential acceleration is nominally insensitive to the system free evolution dominating the slow displacement dynamics of low-...

  6. Test-retest reliability of sensor-based sit-to-stand measures in young and older adults

    NARCIS (Netherlands)

    Regterschot, G. Ruben H.; Zhang, Wei; Baldus, Heribert; Stevens, Martin; Zijlstra, Wiebren

    2014-01-01

    This study investigated test-retest reliability of sensor-based sit-to-stand (STS) peak power and other STS measures in young and older adults. In addition, test-retest reliability of the sensor method was compared to test-retest reliability of the Timed Up and Go Test (TUGT) and Five-Times-Sit-to-S

  7. Interpretation of Key Concepts in Language Testing:Validity, Validation and Reliability

    Institute of Scientific and Technical Information of China (English)

    黄丽娜

    2013-01-01

    Language testing is an important link in language teaching, in this paper, the two important criteria of language test the reliability and validity has carried on the detailed elaboration, in order to a language teacher proposition and evaluation test more scientific.

  8. Feasibility and Reliability of Two Different Walking Tests in People With Severe Intellectual and Sensory Disabilities

    NARCIS (Netherlands)

    Waninge, A.; Evenhuis, I. J.; van Wijck, R.; van der Schans, C. P.

    2011-01-01

    Background The purpose of this study is to describe feasibility and test-retest reliability of the six-minute walking distance test (6MWD) and an adapted shuttle run test (aSRT) in persons with severe intellectual and sensory (multiple) disabilities. Materials and Methods Forty-seven persons with se

  9. Reliability Analysis of Component Software in Wireless Sensor Networks Based on Transformation of Testing Data

    Directory of Open Access Journals (Sweden)

    Chunyan Hou

    2009-08-01

    Full Text Available We develop an approach of component software reliability analysis which includes the benefits of both time domain, and structure based approaches. This approach overcomes the deficiency of existing NHPP techniques that fall short of addressing repair, and internal system structures simultaneously. Our solution adopts a method of transformation of testing data to cover both methods, and is expected to improve reliability prediction. This paradigm allows component-based software testing process doesn’t meet the assumption of NHPP models, and accounts for software structures by the way of modeling the testing process. According to the testing model it builds the mapping relation from the testing profile to the operational profile which enables the transformation of the testing data to build the reliability dataset required by NHPP models. At last an example is evaluated to validate and show the effectiveness of this approach.

  10. Acceleration test of TIT-IHQ linac for heavy ion irradiation

    Science.gov (United States)

    Takashi, Ito; Noriyosu, Hayashizaki; Shinjiro, Matsui; Kimikazu, Sasa; Schubert, H.; Osvath, E.; Toshiyuki, Hattori

    2000-03-01

    We have developed an interdigital-H quadrupole (IHQ) linac for industrial applications. This linac was designed to accelerate particles with charge to mass ratio greater than 1/16 from 21.8 up to 145 keV/u. The particles are focused by an electric quadrupole field exited by fingertips on the drift tubes. This IHQ linac was installed at Tokyo Institute of Technology in 1997 and some tests such as low power tuning and vacuum tests were done. Then, proton acceleration tests ware performed in 1998, and the proton beam was successfully accelerated up to the designed energy. As a result of this experiment, the effective shunt impedance was determined to be 210 MΩ/m, the required RF power consumption was 93 W and the beam transmission rate was about 9%. In this paper, the results of the high power acceleration test with H + ion are described.

  11. Effects of Accelerated Exposure Testing (AET) Conditions on Performance Degradation of Solar Cells and Encapsulants

    Energy Technology Data Exchange (ETDEWEB)

    Glick, S. H.; Pern, F. J.

    2000-01-01

    The paper briefly summarizes the results from several accelerated exposure tests (AET) studies. Causes responsible for the photothermal instability of the encapsulated Si solar cells appear to be multiple and complex.

  12. Accelerated life testing and temperature dependence of device characteristics in GaAs CHFET devices

    Science.gov (United States)

    Gallegos, M.; Leon, R.; Vu, D. T.; Okuno, J.; Johnson, A. S.

    2002-01-01

    Accelerated life testing of GaAs complementary heterojunction field effect transistors (CHFET) was carried out. Temperature dependence of single and synchronous rectifier CHFET device characteristics were also obtained.

  13. Evaluation of accelerated deterioration in NAPTF flexible test pavements

    Institute of Scientific and Technical Information of China (English)

    Kasthurirangan GOPALAKRISHNAN

    2008-01-01

    Previous research studies have successfully demonstrated the use of artificial neural network(ANN)models for predicting critical structural responses and layer moduli of highway flexible pavements.The primary objective of this study was to develop an ANN-based approach for backcalculation of pavement moduli based on heavy weight deflectometer(HWD)test data,especially in the analysis of airport flexible pavements subjected to new generation aircraft(NGA).Two medium-strength subgrade flexible test sections,at the National Airport Pavement Test Facility(NAPTF),were modeled using a finite element(FE) based pavement analysis program,which can consider the non-linear stress-dependent behavior of pavement geomaterials.A multi-layer,feed-forward network which uses an error-backpropagation algorithm was trained to approximate the HWD backcalculation function using the FE program generated synthetic database.At the NAPTF,test sections were subjected to Boeing 777 (B777)trafficking on one lane and Boeing 747(B747)trafficking on the other lane using a test machine.To monitor the effect of traffic and climatic variations on pavement structural responses.HWD tests were conducted on the traffieked lanes and on the untraffieked centerline of test sections as trafficking progressed.The trained ANN models were successfully applied on the actual HWD test data acquired at the NAPTF to predict the asphalt concrete moduli and non-1inear subgrade moduli of the medium-strength subgrade flexible test sections.

  14. Accelerated aging tests of radiation damaged lasers and photodiodes for the CMS tracker optical links

    CERN Document Server

    Gill, K; Batten, J; Cervelli, G; Grabit, R; Jensen, F; Troska, Jan K; Vasey, F

    1999-01-01

    The combined effects of radiation damage and accelerated ageing in COTS lasers and p-i-n photodiodes are presented. Large numbers of these devices are employed in future High Energy Physics experiments and it is vital that these devices are confirmed to be sufficiently robust in terms of both radiation resistance and reliability. Forty 1310 nm InGaAsP edge-emitting lasers (20 irradiated) and 30 InGaAs p- i-n photodiodes (19 irradiated) were aged for 4000 hours at 80 degrees C with periodic measurements made of laser threshold and efficiency, in addition to p-i-n leakage current and photocurrent. There were no sudden failures and there was very little wearout- related degradation in either unirradiated or irradiated sample groups. The results suggest that the tested devices have a sufficiently long lifetime to operate for at least 10 years inside the Compact Muon Solenoid experiment despite being exposed to a harsh radiation environment. (13 refs).

  15. Exploring the reliability and acceptability of cognitive tests for Indigenous Australians: a pilot study.

    Science.gov (United States)

    Dingwall, Kylie M; Gray, Allison O; McCarthy, Annette R; Delima, Jennifer F; Bowden, Stephen C

    2017-08-02

    Reliable cognitive assessment for Indigenous Australians is difficult given that mainstream tests typically rely on Western concepts, content and values. A test's psychometric properties should therefore be assessed prior to use in other cultures. The aim of this pilot study was to examine the reliability and acceptability of four cognitive tests for Australian Aboriginal people. Participants were 40 male and 44 female (N = 84) Aboriginal patients from Alice Springs Hospital. Four tests were assessed for reliability and acceptability - Rowland Universal Dementia Assessment Screen (RUDAS) (n = 19), PEBL Corsi Blocks (Corsi) (n = 19), Story Memory Recall Test (SMRT) (n = 17) and a CogState battery (n = 18). Participants performed one to three of the tests with repeated assessment to determine test-retest reliability. Qualitative interviews were conducted and analysed based on an adapted phenomenological approach to explore test acceptability. An Indigenous Reference Group gave advice and guidance. Intra-class correlations (ICC) for test retest reliability ranged from r = 0.58 (CogState One Back accuracy) to 0.86 (RUDAS). Themes emerged relating to general impressions, impacts on understanding and performance, appropriateness, task preferences and suggested improvements. RUDAS, CogState Identification task, and SMRT showed the highest reliabilities. Overall the tests were viewed as a positive challenge and an opportunity to learn about the brain despite provoking some anxiety in the patients. Caveats for test acceptability included issues related to language, impacts of convalescence and cultural relevance.

  16. Lunar Regenerative Fuel Cell (RFC) Reliability Testing for Assured Mission Success

    Science.gov (United States)

    Bents, David J.

    2009-01-01

    NASA's Constellation program has selected the closed cycle hydrogen oxygen Polymer Electrolyte Membrane (PEM) Regenerative Fuel Cell (RFC) as its baseline solar energy storage system for the lunar outpost and manned rover vehicles. Since the outpost and manned rovers are "human-rated," these energy storage systems will have to be of proven reliability exceeding 99 percent over the length of the mission. Because of the low (TRL=5) development state of the closed cycle hydrogen oxygen PEM RFC at present, and because there is no equivalent technology base in the commercial sector from which to draw or infer reliability information from, NASA will have to spend significant resources developing this technology from TRL 5 to TRL 9, and will have to embark upon an ambitious reliability development program to make this technology ready for a manned mission. Because NASA would be the first user of this new technology, NASA will likely have to bear all the costs associated with its development.When well-known reliability estimation techniques are applied to the hydrogen oxygen RFC to determine the amount of testing that will be required to assure RFC unit reliability over life of the mission, the analysis indicates the reliability testing phase by itself will take at least 2 yr, and could take up to 6 yr depending on the number of QA units that are built and tested and the individual unit reliability that is desired. The cost and schedule impacts of reliability development need to be considered in NASA's Exploration Technology Development Program (ETDP) plans, since life cycle testing to build meaningful reliability data is the only way to assure "return to the moon, this time to stay, then on to Mars" mission success.

  17. Status and Plans for a Superconducting RF Accelerator Test Facility at Fermilab

    Energy Technology Data Exchange (ETDEWEB)

    Leibfritz, J.; Andrews, R.; Baffes, C.M.; Carlson, K.; Chase, B.; Church, M.D.; Harms, E.R.; Klebaner, A.L.; Kucera, M.; Martinez, A.; Nagaitsev, S.; /Fermilab

    2012-05-01

    The Advanced Superconducting Test Accelerator (ASTA) is being constructed at Fermilab. The existing New Muon Lab (NML) building is being converted for this facility. The accelerator will consist of an electron gun, injector, beam acceleration section consisting of 3 TTF-type or ILC-type cryomodules, multiple downstream beam lines for testing diagnostics and conducting various beam tests, and a high power beam dump. When completed, it is envisioned that this facility will initially be capable of generating a 750 MeV electron beam with ILC beam intensity. An expansion of this facility was recently completed that will provide the capability to upgrade the accelerator to a total beam energy of 1.5 GeV. Two new buildings were also constructed adjacent to the ASTA facility to house a new cryogenic plant and multiple superconducting RF (SRF) cryomodule test stands. In addition to testing accelerator components, this facility will be used to test RF power systems, instrumentation, and control systems for future SRF accelerators such as the ILC and Project-X. This paper describes the current status and overall plans for this facility.

  18. Diagnosis of carpal tunnel syndrome: interobserver reliability of the blinded scratch-collapse test.

    Science.gov (United States)

    Blok, Robin D; Becker, Stéphanie J E; Ring, David C

    2014-06-01

    The reliability of the scratch-collapse test for diagnosis of carpal tunnel syndrome (CTS) has not been tested by independent investigators. This study measured the reliability of the scratch-collapse test comparing the treating hand surgeon and blinded evaluators. We performed a prospective observational study of 41 patients with a provisional diagnosis of CTS or a combination of CTS and cubital tunnel syndrome and prescribed electrodiagnostic testing. The treating hand surgeon performed the scratch-collapse test. Next, the test was administered by one of the six observers, unaware of the patient's symptoms and the diagnosis made by treating hand surgeon. The kappa statistic (κ) was used to calculate the interrater reliability between the treating hand surgeons and blinded scratchers. The agreement between the blinded observers and the hand surgeons on the scratch-collapse test was substantial 0.63 (95 % CI, 0.34-0.87; p scratch test in our sample was 32 %. In a small study with a spectrum bias favoring electrophysiologically confirmed CTS the reliability was lower than that reported by the inventors of the test, but was still substantial. We propose a larger study of patients with a greater variety of electrodiagnostic test results using fewer observers with more experience.

  19. Status and Plans for an SRF Accelerator Test Facility at Fermilab

    CERN Document Server

    Church, M; Nagaitsev, S

    2012-01-01

    A superconducting RF accelerator test facility is currently under construction at Fermilab. The accelerator will consist of an electron gun, 40 MeV injector, beam acceleration section consisting of 3 TTF-type or ILC-type cryomodules, and multiple downstream beam lines for testing diagnostics and performing beam experiments. With 3 cryomodules installed this facility will initially be capable of generating an 810 MeV electron beam with ILC beam intensity. The facility can accommodate up to 6 cryomodules for a total beam energy of 1.5 GeV. This facility will be used to test SRF cryomodules under high intensity beam conditions, RF power equipment, instrumentation, and LLRF and controls systems for future SRF accelerators such as the ILC and Project-X. This paper describes the current status and overall plans for this facility.

  20. Reliability of the Test of Integrated Language and Literacy Skills (TILLS).

    Science.gov (United States)

    Mailend, Marja-Liisa; Plante, Elena; Anderson, Michele A; Applegate, E Brooks; Nelson, Nickola W

    2016-07-01

    As new standardized tests become commercially available, it is critical that clinicians have access to the information about a test's psychometric properties, including aspects of reliability. The purpose of the three studies reported in this article was to investigate the reliability of a new test, the Test of Integrated Language and Literacy Skills (TILLS), with consideration of both internal and external sources of measurement error. The TILLS was administered to children aged 6;0-18;11 years. The participants varied in terms of their language and literacy skills and included children with typical language development as well as those diagnosed with language or learning disability. The sample of children also varied in terms of their racial and socioeconomic backgrounds. Study 1 (N = 1056) assessed the internal consistency of TILLS calculating the coefficient omega for each subtest. Study 2 (N = 103) and Study 3 (N = 39) used the intra-class correlation coefficients to report on test-retest and inter-rater reliability respectively. The results indicate strong internal consistency and inter-rater reliability for all subtests of TILLS. The test-retest reliability was strong for all but one subtest, for which the intra-class correlation coefficient was in the acceptable range. This article provides clinicians with essential scientific information that supports the internal and external reliability of a new test of oral and written language skills, the TILLS. Information about reliability is critical for guiding the selection of an appropriate diagnostic tool amongst a number of options. © 2016 Royal College of Speech and Language Therapists.

  1. Accelerated fatigue testing of LM 19.1 blades

    DEFF Research Database (Denmark)

    Kristensen, Ole Jesper Dahl; Jørgensen, E.

    2003-01-01

    material. In addition to the thermal imaging surveillance the blades were instrumented with strain gauges. This report presents the temperature duringtest, calibration test results, moment range measurements, strain statistics, thermal imaging registrations and a determination of the size and cause...

  2. Accelerated Life Test for Photovoltaic Cells Using Concentrated Light

    OpenAIRE

    Daniel Tudor Cotfas; Petru Adrian Cotfas; Dan Ion Floroian; Laura Floroian

    2016-01-01

    This paper presents a new method developed to significantly reduce the necessary time for the ageing tests for different types of photovoltaic cells. Two ageing factors have been applied to the photovoltaic cells: the concentrated light and the temperature. The maximum power of the photovoltaic cells was monitored during the ageing process. The electrical dc and ac parameters of the photovoltaic cells were measured and analyzed at 1 sun irradiance, before and after the test stress. During the...

  3. Reliability testing of a portfolio assessment tool for postgraduate family medicine training in South Africa

    Directory of Open Access Journals (Sweden)

    Louis Jenkins

    2013-01-01

    Full Text Available Background: Competency-based education and the validity and reliability of workplace-based assessment of postgraduate trainees have received increasing attention worldwide.Family medicine was recognised as a speciality in South Africa six years ago and a satisfactory portfolio of learning is a prerequisite to sit the national exit exam. A massive scaling up of the number of family physicians is needed in order to meet the health needs of the country.Aim: The aim of this study was to develop a reliable, robust and feasible portfolio assessment tool (PAT for South Africa.Methods: Six raters each rated nine portfolios from the Stellenbosch University programme, using the PAT, to test for inter-rater reliability. This rating was repeated three months later to determine test–retest reliability. Following initial analysis and feedback the PAT was modified and the inter-rater reliability again assessed on nine new portfolios. An acceptable intra-classcorrelation was considered to be > 0.80.Results: The total score was found to be reliable, with a coefficient of 0.92. For test–retest reliability, the difference in mean total score was 1.7%, which was not statistically significant. Amongst the subsections, only assessment of the educational meetings and the logbook showed reliability coefficients > 0.80.Conclusion: This was the first attempt to develop a reliable, robust and feasible national portfolio assessment tool to assess postgraduate family medicine training in the South African context. The tool was reliable for the total score, but the low reliability of several sections in the PAT helped us to develop 12 recommendations regarding the use of the portfolio, the design of the PAT and the training of raters.

  4. Reliability testing of a portfolio assessment tool for postgraduate family medicine training in South Africa

    Science.gov (United States)

    Mash, Bob; Derese, Anselme

    2013-01-01

    Abstract Background Competency-based education and the validity and reliability of workplace-based assessment of postgraduate trainees have received increasing attention worldwide. Family medicine was recognised as a speciality in South Africa six years ago and a satisfactory portfolio of learning is a prerequisite to sit the national exit exam. A massive scaling up of the number of family physicians is needed in order to meet the health needs of the country. Aim The aim of this study was to develop a reliable, robust and feasible portfolio assessment tool (PAT) for South Africa. Methods Six raters each rated nine portfolios from the Stellenbosch University programme, using the PAT, to test for inter-rater reliability. This rating was repeated three months later to determine test–retest reliability. Following initial analysis and feedback the PAT was modified and the inter-rater reliability again assessed on nine new portfolios. An acceptable intra-class correlation was considered to be > 0.80. Results The total score was found to be reliable, with a coefficient of 0.92. For test–retest reliability, the difference in mean total score was 1.7%, which was not statistically significant. Amongst the subsections, only assessment of the educational meetings and the logbook showed reliability coefficients > 0.80. Conclusion This was the first attempt to develop a reliable, robust and feasible national portfolio assessment tool to assess postgraduate family medicine training in the South African context. The tool was reliable for the total score, but the low reliability of several sections in the PAT helped us to develop 12 recommendations regarding the use of the portfolio, the design of the PAT and the training of raters.

  5. Development and testing of the improved focusing quadrupole for heavy ion fusion accelerators

    Energy Technology Data Exchange (ETDEWEB)

    Manahan, R R; Martovetsky, N N; Meinke, R B; Chiesa, L; Lietzke, A F; Sabbi, G L; Seidl, P A

    2003-10-23

    An improved version of the focusing magnet for a Heavy Ion Fusion (HIF) accelerator was designed, built and tested in 2002-2003. This quadrupole has higher focusing power and lower error field than the previous version of the focusing quadrupoles successfully built and tested in 2001. We discuss the features of the new design, selected fabrication issues and test results.

  6. Content validity and reliability of test of gross motor development in Chilean children

    Directory of Open Access Journals (Sweden)

    Marcelo Cano-Cappellacci

    2015-01-01

    Full Text Available ABSTRACT OBJECTIVE To validate a Spanish version of the Test of Gross Motor Development (TGMD-2 for the Chilean population. METHODS Descriptive, transversal, non-experimental validity and reliability study. Four translators, three experts and 92 Chilean children, from five to 10 years, students from a primary school in Santiago, Chile, have participated. The Committee of Experts has carried out translation, back-translation and revision processes to determine the translinguistic equivalence and content validity of the test, using the content validity index in 2013. In addition, a pilot implementation was achieved to determine test reliability in Spanish, by using the intraclass correlation coefficient and Bland-Altman method. We evaluated whether the results presented significant differences by replacing the bat with a racket, using T-test. RESULTS We obtained a content validity index higher than 0.80 for language clarity and relevance of the TGMD-2 for children. There were significant differences in the object control subtest when comparing the results with bat and racket. The intraclass correlation coefficient for reliability inter-rater, intra-rater and test-retest reliability was greater than 0.80 in all cases. CONCLUSIONS The TGMD-2 has appropriate content validity to be applied in the Chilean population. The reliability of this test is within the appropriate parameters and its use could be recommended in this population after the establishment of normative data, setting a further precedent for the validation in other Latin American countries.

  7. Intra- and inter-tester reliability of sensibility testing in leprosy.

    Science.gov (United States)

    van Brakel, W H; Khawas, I B; Gurung, K S; Kets, C M; van Leerdam, M E; Drever, W

    1996-09-01

    We conducted an intra- and inter-tester agreement study of three sensory screening tests used in nerve function assessment of leprosy patients: the Semmes-Weinstein monofilament (SWM) test, moving 2-point discrimination (M2PD), and the pin prick test. The weighted kappa (Kw) statistic was used as the reliability coefficient. The SWM had intra-observer Kws ranging from 0.83 to 0.92 and inter-observer Kws ranging from 0.76 to 0.89. The M2PD had intra- and inter-tester Kws ranging from 0.75 to 0.82 and 0.54 to 0.82, respectively. Inter-tester agreement for the pin prick test ranged from 0.45 to 0.85. There was evidence that the main source of variability between testers was testing skill and experience. Among the experienced physiotechnicians there was no significant difference between intra- and inter-tester reliability. We conclude that reliability of the SWM test was very good, closely followed by the M2PD test. Reliability of the pin prick test was less good than that of the SWM and M2PD, making it less suitable for serial testing.

  8. Reliability and criterion-related validity with a smartphone used in timed-up-and-go test.

    Science.gov (United States)

    Galán-Mercant, Alejandro; Barón-López, Francisco Javier; Labajos-Manzanares, María T; Cuesta-Vargas, Antonio I

    2014-12-02

    The capacity to diagnosys, quantify and evaluate movement beyond the general confines of a clinical environment under effectiveness conditions may alleviate rampant strain on limited, expensive and highly specialized medical resources. An iPhone 4® mounted a three dimensional accelerometer subsystem with highly robust software applications. The present study aimed to evaluate the reliability and concurrent criterion-related validity of the accelerations with an iPhone 4® in an Extended Timed Get Up and Go test. Extended Timed Get Up and Go is a clinical test with that the patient get up from the chair and walking ten meters, turn and coming back to the chair. A repeated measure, cross-sectional, analytical study. Test-retest reliability of the kinematic measurements of the iPhone 4® compared with a standard validated laboratory device. We calculated the Coefficient of Multiple Correlation between the two sensors acceleration signal of each subject, in each sub-stage, in each of the three Extended Timed Get Up and Go test trials. To investigate statistical agreement between the two sensors we used the Bland-Altman method. With respect to the analysis of the correlation data in the present work, the Coefficient of Multiple Correlation of the five subjects in their triplicated trials were as follows: in sub-phase Sit to Stand the ranged between r = 0.991 to 0.842; in Gait Go, r = 0.967 to 0.852; in Turn, 0.979 to 0.798; in Gait Come, 0.964 to 0.887; and in Turn to Stand to Sit, 0.992 to 0.877. All the correlations between the sensors were significant (p Timed Get Up and Go test. The inertial sensor mounted in the iPhone 4® is sufficiently reliable and accurate to evaluate and identify the kinematic patterns in an Extended Timed Get and Go test. While analysis and interpretation of 3D kinematics data continue to be dauntingly complex, the iPhone 4® makes the task of acquiring the data relatively inexpensive and easy to use.

  9. Reliable and Valid Procedures to Create an Authentic Listening Test in EFL Context

    Institute of Scientific and Technical Information of China (English)

    吴婷

    2012-01-01

      Listening testing is a universal social activity, especially for school life as well as an indispensable part to language as⁃sessment. How test takers perform during the tests may affect their entry to many significant roles both in society and schools. This paper is an attempt to explore how to design a reliable and valid listening test for particular purposes in EFL context.

  10. Study of Optimal Perimetric Testing in Children (OPTIC: Feasibility, Reliability and Repeatability of Perimetry in Children.

    Directory of Open Access Journals (Sweden)

    Dipesh E Patel

    Full Text Available To investigate feasibility, reliability and repeatability of perimetry in children.A prospective, observational study recruiting 154 children aged 5-15 years, without an ophthalmic condition that affects the visual field (controls, identified consecutively between May 2012 and November 2013 from hospital eye clinics. Perimetry was undertaken in a single sitting, with standardised protocols, in a randomised order using the Humphrey static (SITA 24-2 FAST, Goldmann and Octopus kinetic perimeters. Data collected included test duration, subjective experience and test quality (incorporating examiner ratings on comprehension of instructions, fatigue, response to visual and auditory stimuli, concentration and co-operation to assess feasibility and reliability. Testing was repeated within 6 months to assess repeatability.Overall feasibility was very high (Goldmann=96.1%, Octopus=89% and Humphrey=100% completed the tests. Examiner rated reliability was 'good' in 125 (81.2% children for Goldmann, 100 (64.9% for Octopus and 98 (63.6% for Humphrey perimetry. Goldmann perimetry was the most reliable method in children under 9 years of age. Reliability improved with increasing age (multinomial logistic regression (Goldmann, Octopus and Humphrey, p<0.001. No significant differences were found for any of the three test strategies when examining initial and follow-up data outputs (Bland-Altman plots, n=43, suggesting good test repeatability, although the sample size may preclude detection of a small learning effect.Feasibility and reliability of formal perimetry in children improves with age. By the age of 9 years, all the strategies used here were highly feasible and reliable. Clinical assessment of the visual field is achievable in children as young as 5 years, and should be considered where visual field loss is suspected. Since Goldmann perimetry is the most effective strategy in children aged 5-8 years and this perimeter is no longer available, further

  11. Development, construct validity and test-retest reliability of a field-based wheelchair mobility performance test for wheelchair basketball

    NARCIS (Netherlands)

    de Witte, Annemarie M H; Hoozemans, Marco J M; Berger, Monique A M; van der Slikke, Rienk M A; van der Woude, Lucas H V; Veeger, Dirkjan H E J

    2017-01-01

    The aim of this study was to develop and describe a wheelchair mobility performance test in wheelchair basketball and to assess its construct validity and reliability. To mimic mobility performance of wheelchair basketball matches in a standardised manner, a test was designed based on observation of

  12. Test-retest reliability of lower limb isokinetic endurance in COPD: a comparison of angular velocities

    Directory of Open Access Journals (Sweden)

    Ribeiro F

    2015-06-01

    Full Text Available Fernanda Ribeiro,* Pierre-Alexis Lépine,* Corine Garceau-Bolduc, Valérie Coats, Étienne Allard, François Maltais, Didier Saey Centre de recherche de l’Institut Universitaire de cardiologie et de pneumologie de Québec, Université Laval, Québec, Canada *These authors contributed equally to this workBackground: The purpose of this study was to determine and compare the test-retest reliability of quadriceps isokinetic endurance testing at two knee angular velocities in patients with chronic obstructive pulmonary disease (COPD. Methods: After one familiarization session, 14 patients with moderate to severe COPD (mean age 65±4 years; forced expiratory volume in 1 second (FEV1 55%±18% predicted performed two quadriceps isokinetic endurance tests on two separate occasions within a 5–7-day interval. Quadriceps isokinetic endurance tests consisted of 30 maximal knee extensions at angular velocities of 90° and 180° per second, performed in random order. Test-retest reliability was assessed for peak torque, muscle endurance, work slope, work fatigue index, and changes in FEV1 for dyspnea and leg fatigue from rest to the end of the test. The intraclass correlation coefficient, minimal detectable change, and limits of agreement were calculated. Results: High test-retest reliability was identified for peak torque and muscle total work at both velocities. Work fatigue index was considered reliable at 90° per second but not at 180° per second. A lower reliability was identified for dyspnea and leg fatigue scores at both angular velocities. Conclusion: Despite a limited sample size, our findings su pport the use of a 30-maximal repetition isokinetic muscle testing procedure at angular velocities of 90° and 180° per second in patients with moderate to severe COPD. Endurance measurement (total isokinetic work at 90° per second was highly reliable, with a minimal detectable change at the 95% confidence level of 10%. Peak torque and fatigue index

  13. Keitel Functional Test for patients with rheumatoid arthritis: translation, reliability, validity, and responsiveness

    DEFF Research Database (Denmark)

    Jacobsen, S.; Skjodt, H.; Klarlund, M.;

    2008-01-01

    BACKGROUND AND PURPOSE: The purpose of this study was to translate the German Keitel Functional Test (KFT) into Danish and test it for reliability, concurrent and predictive validity, and responsiveness in patients with rheumatoid arthritis (RA). METHODS: Translation of the KFT was performed acco...

  14. Test-Retest Reliability in fMRI of Language: Group and Task Effects

    Science.gov (United States)

    Chen, E. Elinor; Small, Steven L.

    2007-01-01

    This paper explores how the test-retest reliability is modulated by different groups of participants and experimental tasks. A group of 12 healthy participants and a group of nine stroke patients performed the same language imaging experiment twice, test and retest, on different days. The experiment consists of four conditions, one audio condition…

  15. Lexical Testing and the Reliability of the Modified Vocabulary Knowledge Scale

    Directory of Open Access Journals (Sweden)

    Debbita Tan

    2016-10-01

    Full Text Available This paper highlights some of the vocabulary tests available, and reports the reliability of the modified Vocabulary Knowledge Scale (VKS (Rosszell, 2007. Although there is no consensus as to what actually constitutes vocabulary knowledge, the notion that it is made up of receptive knowledge (words recognised or known when seen or heard and productive knowledge (words appropriately used when we write or speak is widely accepted. Lexical testing is important for various reasons, chiefly to determine reading ability which requires the use of a size test, and to monitor overall vocabulary development which necessitates the use of a test measuring both receptive and productive knowledge (for instance, the modified VKS. The modified VKS was pilot-tested on 28 university-level Malaysian remedial English language learners and analysed for ‘reliability as stability over similar samples’. Data analyses returned values indicating the test to be reliable, thus presenting it as a feasible option for use among similar cohorts. This is of significance to scholars, researchers, language instructors and curriculum designers intending to employ the test in their own research, classrooms and literacy programmes.Keywords: lexical testing, receptive and productive vocabulary knowledge, modified Vocabulary Knowledge Scale, reliability, tertiary learners 

  16. An Examination of Reliability and Validity Claims of a Foreign Language Proficiency Test

    Science.gov (United States)

    Mircea-Pines, Walter J.

    2009-01-01

    This dissertation study examined the reliability and validity claims of a modified version of the Spanish Modern Language Association Foreign Language Proficiency Test for Teachers and Advanced Students administered at George Mason University (GMU). The study used the 1999 computerized GMU version that was administered to 277 test-takers via…

  17. Test-retest, inter-assessor and intra-assessor reliability of the modified Touwen examination

    NARCIS (Netherlands)

    Peters, Lieke H. J.; Maathuis, Karel G. B.; Kouw, Eva; Hamming, Marjolein; Hadders-Algra, Mijna

    2008-01-01

    Interest in the Touwen examination (1979) for the assessment of minor neurological dysfunction (MND) is growing. However, information on psychometric properties of this assessment is scarce. Therefore the present study aimed at assessing the test's test-retest, inter- and intra-assessor reliability.

  18. Developing a Science Process Skills Test for Secondary Students: Validity and Reliability Study

    Science.gov (United States)

    Feyzioglu, Burak; Demirdag, Baris; Akyildiz, Murat; Altun, Eralp

    2012-01-01

    Science process skills are claimed to enable an individual to improve their own life visions and give a scientific view/literacy as a standard of their understanding about the nature of science. The main purpose of this study was to develop a test for measuring a valid, reliable and practical test for Science Process Skills (SPS) in secondary…

  19. The interval shuttle run test for intermittent sport players : evaluation of reliability

    NARCIS (Netherlands)

    Lemmink, K.A.P.M.; Visscher, C.; Lambert, M.I.; Lamberts, R.P.

    2004-01-01

    The reliability of the interval shuttle run test (ISRT) as a submaximal and maximal field test to measure intermittent endurance capacity was examined. During the ISRT, participants alternately run for 30 seconds and walk for 15 seconds. The running speed is increased from 10 km.h(-1) every 90 secon

  20. Test-retest reliability of Eurofit Physical Fitness items for children with visual impairments

    NARCIS (Netherlands)

    Houwen, Suzanne; Visscher, Chris; Hartman, Esther; Lemmink, Koen A. P. M.

    2006-01-01

    The purpose of this study was to examine the test-retest reliability of physical fitness items from the European Test of Physical Fitness (Eurofit) for children with visual impairments. A sample of 21 children, ages 6-12 years, that were recruited from a special school for children with visual impai

  1. Reliability and feasibility of the six minute walk test in subjects with myotonic dystrophy.

    Science.gov (United States)

    Kierkegaard, Marie; Tollbäck, Anna

    2007-12-01

    The objective was to describe test-retest reliability and feasibility of the six minute walk test in adult subjects with myotonic dystrophy type 1. Twelve subjects (28-68 years, mean 44) performed three six minute walk tests on two occasions, one week apart. Relative reliability was high (ICC(2.1)=0.99) and absolute reliability values were low (standard error of measurement 12 m, repeatability 33 m). Feasibility was investigated in a sample of 64 subjects (19-70 years, mean 43). Fifty-two subjects were able to perform two tests on the same day. Subjects with severe proximal weakness had difficulties performing repeated tests. A practice trial followed by a second test on the same day can be recommended for most subjects, and the best test should be used for evaluations. In conclusion, even though the study sample was small, the present study indicates that the six minute walk test is reliable and feasible in subjects with myotonic dystrophy type 1.

  2. The steep ramp test in healthy children and adolescents: reliability and validity

    NARCIS (Netherlands)

    Bongers, B.C.; Vries, S.I. de; Helders, P.J.M.; Takken, T.

    2013-01-01

    PURPOSE: This study aimed to examine the reliability and validity of the steep ramp test (SRT), a feasible, maximal exercise test on a cycle ergometer that does not require the use of respiratory gas analysis, in healthy children and adolescents.METHODS: Seventy-five children were randomly divided i

  3. Novel accelerated corrosion test for LY12CZ and LC4CS aluminum alloys

    Institute of Scientific and Technical Information of China (English)

    CAI Jian-ping; LIU Ming

    2006-01-01

    A new accelerated corrosion test-comprehensive environmental test (CET) was developed in order to estimate the outdoor corrosion of aluminum alloys in marine environment. The environmental characteristics in CET were studied by atmospheric corrosion monitor (ACM), and the morphology of corrosion product was observed by SEM. The correlation between the accelerated corrosion tests and outdoor exposure was discussed. The results show that the anti-corrosion ranking for LY12CZ, LC4CS, clad LY12CZ, and clad LC4CS in CET is the same as that of the alloys exposed outdoor, and ACM study shows that CET demonstrates the same environmental characteristics as that exposed outdoor. CET is a more accurate accelerated corrosion test, and a mathematical relation was obtained to describe the relation between CET and outdoor test.

  4. Evaluation of the Accelerate Pheno System for Fast Identification and Antimicrobial Susceptibility Testing from Positive Blood Cultures in Bloodstream Infections Caused by Gram-Negative Pathogens.

    Science.gov (United States)

    Marschal, Matthias; Bachmaier, Johanna; Autenrieth, Ingo; Oberhettinger, Philipp; Willmann, Matthias; Peter, Silke

    2017-07-01

    Bloodstream infections (BSI) are an important cause of morbidity and mortality. Increasing rates of antimicrobial-resistant pathogens limit treatment options, prompting an empirical use of broad-range antibiotics. Fast and reliable diagnostic tools are needed to provide adequate therapy in a timely manner and to enable a de-escalation of treatment. The Accelerate Pheno system (Accelerate Diagnostics, USA) is a fully automated test system that performs both identification and antimicrobial susceptibility testing (AST) directly from positive blood cultures within approximately 7 h. In total, 115 episodes of BSI with Gram-negative bacteria were included in our study and compared to conventional culture-based methods. The Accelerate Pheno system correctly identified 88.7% (102 of 115) of all BSI episodes and 97.1% (102 of 105) of isolates that are covered by the system's identification panel. The Accelerate Pheno system generated an AST result for 91.3% (95 of 104) samples in which the Accelerate Pheno system identified a Gram-negative pathogen. The overall category agreement between the Accelerate Pheno system and culture-based AST was 96.4%, the rates for minor discrepancies 1.4%, major discrepancies 2.3%, and very major discrepancies 1.0%. Of note, ceftriaxone, piperacillin-tazobactam, and carbapenem resistance was correctly detected in blood culture specimens with extended-spectrum beta-lactamase-producing Escherichia coli (n = 7) and multidrug-resistant Pseudomonas aeruginosa (n = 3) strains. The utilization of the Accelerate Pheno system reduced the time to result for identification by 27.49 h (P based methods in our laboratory setting. In conclusion, the Accelerate Pheno system provided fast, reliable results while significantly improving turnaround time in blood culture diagnostics of Gram-negative BSI. Copyright © 2017 American Society for Microbiology.

  5. Fukuda and Babinski-Weil tests: within-subject variability and test-retest reliability in nondisabled adults.

    Science.gov (United States)

    Paquet, Nicole; Taillon-Hobson, Anne; Lajoie, Yves

    2014-01-01

    The Fukuda Stepping Test and the Babinski-Weil test are clinical assessments that presumably reveal unilateral vestibular hypofunction. However, abnormal performances on both of these two tests have been found in nondisabled individuals. This study compared measures of lateral and longitudinal displacements and body rotation for both tests, as well as the within-subject variability and test-retest reliability of the measures. In addition, correlations between hand and foot dominance and these measures were studied. Fifty young, nondisabled participants performed three trials of the 100-step Fukuda test and three trials of the Babinski-Weil test. The testing session was repeated 7 d later (retest). Lateral displacement, body rotation, and within-subject variability of these two measures were larger on the Fukuda than the Babinski-Weil test. No difference in test-retest reliability was found between the two tests, and a significant correlation was found between body rotation on the Fukuda test and score on the Waterloo Footedness Questionnaire. There may have been smaller variability in results of the Babinski-Weil test because it contains fewer steps (36) than the 100-step Fukuda test. Future research should compare tests with an equal number of steps; but, in the meantime, the Babinski-Weil test seems to have better psychometric properties than the Fukuda test, at least in nondisabled individuals.

  6. Accounting for Proof Test Data in a Reliability Based Design Optimization Framework

    Science.gov (United States)

    Ventor, Gerharad; Scotti, Stephen J.

    2012-01-01

    This paper investigates the use of proof (or acceptance) test data during the reliability based design optimization of structural components. It is assumed that every component will be proof tested and that the component will only enter into service if it passes the proof test. The goal is to reduce the component weight, while maintaining high reliability, by exploiting the proof test results during the design process. The proposed procedure results in the simultaneous design of the structural component and the proof test itself and provides the designer with direct control over the probability of failing the proof test. The procedure is illustrated using two analytical example problems and the results indicate that significant weight savings are possible when exploiting the proof test results during the design process.

  7. Accelerated ultrasonic fatigue testing applications and research trends

    Energy Technology Data Exchange (ETDEWEB)

    Cho, In Sik; Shin, Choongshig; Kim, Jong Yup; Jeon, Yongho [Ajou Univ., Gyeonggi (Somalia)

    2012-06-15

    Very high cycle fatigue (VHCF) behavior of aerospace components has emerged much attention due to their long service life. In this study, a piezoelectric ultrasonic fatigue testing (UFT) system has been developed by Mbrosiatec Co., Ltd. to study the high cycle fatigue (HCF) strength of Ti 6Al 4V alloy. Hourglass shaped specimens have been investigated in the range from 10'6' to 10'9' cycles at room temperature under completely reversed R=-1 loading conditions, Scanning electron microscopy (SEM) analysis revealed that failures occurred in the entire range up to the gigacycle regime, and the fractures have been found to be initiated from the surface, unlike in steels. However, it was found from the SEM microgprahs that microcracks transformed into intergranular fractures. Thus, it can be concluded from according to the results that this test method can be applicable to commercialized automotive and railroad parts that require high cycle fatigue strength.

  8. Physical design and cooling test of C-band standing wave accelerating tube

    Institute of Scientific and Technical Information of China (English)

    Bai Wei; Xu Zhou; Jin Xiao; Li Ming

    2006-01-01

    The physical design and cooling test of a C-band 2MeV standing wave (SW) accelerating tube are described in this paper. The designed accelerating structure consists of 3-cell buncher and 4-cell accelerating section with a total length of about 163mm , excited with 1MW magnetron. Dynamic simulation presents that about 150mA beam pulse current and 30% capture efficiency can be achieved. By means of nonlinear Gauss fit on electron transverse distribution, the diameter of beam spot FWHM (full width at half maximum of density distribution) is about 0.55mm. Cooling test results of the accelerating tube show that frequencies of cavities are tuned to 5527MHz and the field distribution of bunching section is about 3:9:10.

  9. Benefits of Considering More than Temperature Acceleration for GaN HEMT Life Testing

    Directory of Open Access Journals (Sweden)

    Ronald A. Coutu

    2016-06-01

    Full Text Available The purpose of this work was to investigate the validity of Arrhenius accelerated-life testing when applied to gallium nitride (GaN high electron mobility transistors (HEMT lifetime assessments, where the standard assumption is that only critical stressor is temperature, which is derived from operating power, device channel-case, thermal resistance, and baseplate temperature. We found that power or temperature alone could not explain difference in observed degradation, and that accelerated life tests employed by industry can benefit by considering the impact of accelerating factors besides temperature. Specifically, we found that the voltage used to reach a desired power dissipation is important, and also that temperature acceleration alone or voltage alone (without much power dissipation is insufficient to assess lifetime at operating conditions.

  10. Design and Factory Test of the E /E- Frascati Linear Accelerator for DAFNE

    Energy Technology Data Exchange (ETDEWEB)

    Anamkath, H.; Lyons, S.; Nett, D.; Treas, P.; Whitham, K.; Zante, T.; /Titan Beta, Dublin; Miller, R.; /Titan Beta, Dublin /SLAC; Boni, R.; Hsieh, H.; Sannibale, F.; Vescovi, M.; Vignola, G.; /Frascati

    2011-11-28

    The electron-positron accelerator for the DAFNE project has been built and is in test at Titan Beta in Dublin, CA. This S-Band RF linac system utilizes four 45 MW sledded klystrons and 16-3 m accelerating structures to achieve the required performance. It delivers a 4 ampere electron beam to the positron converter and accelerates the resulting positrons to 550 MeV. The converter design uses a 4.3T pulsed tapered flux compressor along with a pseudo-adiabatic tapered field to a 5 KG solenoid over the first two positron accelerating sections. Quadrupole focusing is used after 100 MeV. The system performance is given in Table 1. This paper briefly describes the design and development of the various subassemblies in this system and gives the initial factory test data.

  11. Reliability of Arm Curl and Chair Stand tests for assessing muscular endurance in older people

    Directory of Open Access Journals (Sweden)

    Boneth M

    2012-05-01

    Full Text Available Objective: to assess the test-retest reliability and level of agreement between measures of the 30 second (30-s Arm Curl and 30-s Chair Stand test in a sample of older adults from Bucaramanga. Materials and methods: a study of evaluation of diagnostic technology was done. Both tests were administered by the same evaluator to 111 adults older than 59 year-old (70,4 ± 7,3, on two occasions, with an interval of time between measures of 4 to 8 days. In the analysis, test-retest reliability was determined using the Intraclass Correlation Coefficient ICC= 2,1 with their confidence interval 95% (CI 95% respective. The agreement level was established by the Bland and Altman method. Results: the test-retest reproducibility of the 30-s Arm Curl test was very good ICC= 0,88 and to the Chair Stand test was good ICC= 0,78. The agreement was very good for both tests of muscle endurance. The CI 95% were between -3,8 and 3,2 stands to 30-s Chair Stand test and between -3,1 and 2,8 curls to 30-s Arm Curl test. Conclusion: the 30-s Arm Curl and 30-s Chair Stand test have good reliability and agreement to assess muscle endurance in older adults functionally independent.

  12. Reasoning with Inductive Argument Test: A Study of Validity and Reliability

    Directory of Open Access Journals (Sweden)

    Mehmet Emrah Karadere

    2013-11-01

    Full Text Available Reasoning with Inductive Argument Test:A Study of Validity and Reliability Objective: The aim of our study is to research reliability and validity and to evaluate the usability of Turkish version of Reasoning with Inductive Argument Test (RIAT in Turkish healty population. Method: 51 healty volunteers who work in Ankara Dıskapi Yildirim Beyazit Research and Training Hospital participated in this study. Reasoning with Inductive Argument Test (RIAT was translated into Turkish by three clinical good knowledge of English. Participants were given a sociodemographic data form, and RIAT were performed by clinicians. To test the reliability of the Turkish version of RIAT, Cronbach’s alpha coefficient was calculated and the halving method was used for the test. Results: The internal consistency of the Reasoning with Inductive Argument Test (RIAT items, Cronbach’s alpha internal consistency coefficient measurements of 0.73 was found to be statistically significant. Spearman-Brown coefficient that determines the reliability of the whole test r=0.74 was found. Kurtosis values of all the items was below 1.5 and the percentages in the second evaluation were mainly lower. At the same time, both change in belief between self produced RIAT options and given RIAT options (p=0.02, z=-2296 as well as changes in beliefs between related and unrelated items for Obsessive Compulsive Disorder (OCD difference (p=0.03, z=-2.199 were significant. Conclusion: The preliminary data obtained from the study of reliability and validity of the scale shows that ‘Reasoning with Inductive Argument Test’ supports reliability and validity in Turkish population.

  13. Life Prediction on a T700 Carbon Fiber Reinforced Cylinder with Limited Accelerated Life Testing Data

    Directory of Open Access Journals (Sweden)

    Ma Xiaobing

    2015-01-01

    Full Text Available An accelerated life testing investigation was conducted on a composite cylinder that consists of aluminum alloy and T700 carbon fiber. The ultimate failure stress predictions of cylinders were obtained by the mixing rule and verified by the blasting static pressure method. Based on the stress prediction of cylinder under working conditions, the constant stress accelerated life test of the cylinder was designed. However, the failure data cannot be sufficiently obtained by the accelerated life test due to the time limitation. Therefore, most of the data presented to be high censored in high stress level and zero-failure data in low stress level. When using the traditional method for rupture life prediction, the results showed to be of lower confidence. In this study, the consistency of failure mechanism for carbon fiber and cylinder was analyzed firstly. According to the analysis result, the statistical test information of carbon fiber could be utilized for the accelerated model constitution. Then, rupture life prediction method for cylinder was proposed based on the accelerated life test data and carbon fiber test data. In this way, the life prediction accuracy of cylinder could be improved obviously, and the results showed that the accuracy of this method increased by 35%.

  14. Technological Issues and High Gradient Test Results on X-Band Molybdenum Accelerating Structures

    Energy Technology Data Exchange (ETDEWEB)

    Spataro, B.; /LNF, Dafne Light; Alesini, D.; /LNF, Dafne Light; Chimenti, V.; /LNF, Dafne Light; Dolgashev, V.; /SLAC; Haase, A.; /SLAC; Tantawi, S.G.; /SLAC; Higashi, Y.; /KEK, Tsukuba; Marrelli, C.; /Rome U.; Mostacci, A.; /Rome U.; Parodi, R.; /INFN, Genoa; Yeremian, A.D.; /SLAC

    2012-04-24

    Two 11.424 GHz single cell standing wave accelerating structures have been fabricated for high gradient RF breakdown studies. Both are brazed structures: one made from copper and the other from sintered molybdenum bulk. The tests results are presented and compared to those of similar devices constructed at SLAC (Stanford Linear Accelerator Center) and KEK (Ko Enerugi Kasokuki Kenkyu Kiko). The technological issues to build both sections are discussed.

  15. Technological issues and high gradient test results on X-band molybdenum accelerating structures

    Energy Technology Data Exchange (ETDEWEB)

    Spataro, B., E-mail: bruno.spataro@lnf.infn.it [INFN-LNF, Via E. Fermi 40, 00044 Frascati (Italy); Alesini, D.; Chimenti, V. [INFN-LNF, Via E. Fermi 40, 00044 Frascati (Italy); Dolgashev, V.; Haase, A.; Tantawi, S.G. [SLAC, 2575 Sand Hill Road, Menlo Park, CA 94025 (United States); Higashi, Y. [KEK 1-1 Oho, Tsukuba, Ibaraki, 305-0801 (Japan); Marrelli, C.; Mostacci, A. [University of Rome Sapienza, Department of Fundamental and Applied Science for Engineering, Via A. Scarpa 14, 00185 Rome (Italy); Parodi, R. [INFN-Genova, Via Dodecaneso 33, 16146 Genova (Italy); Yeremian, A.D. [SLAC, 2575 Sand Hill Road, Menlo Park, CA 94025 (United States)

    2011-11-21

    Two 11.424 GHz single cell standing wave accelerating structures have been fabricated for high gradient RF breakdown studies. Both are brazed structures: one made from copper and the other from sintered molybdenum bulk. The tests results are presented and compared to those of similar devices constructed at SLAC (Stanford Linear Accelerator Center) and KEK (Ko Enerugi Kasokuki Kenkyu Kiko). The technological issues to build both sections are discussed.

  16. Reliability and criterion-related validity of a new repeated agility test

    Directory of Open Access Journals (Sweden)

    MS Fessi

    2016-04-01

    Full Text Available The study aimed to assess the reliability and the criterion-related validity of a new repeated sprint T-test (RSTT that includes intense multidirectional intermittent efforts. The RSTT consisted of 7 maximal repeated executions of the agility T-test with 25 s of passive recovery rest in between. Forty-five team sports players performed two RSTTs separated by 3 days to assess the reliability of best time (BT and total time (TT of the RSTT. The intra-class correlation coefficient analysis revealed a high relative reliability between test and retest for BT and TT (>0.90. The standard error of measurement (<0.50 showed that the RSTT has a good absolute reliability. The minimal detectable change values for BT and TT related to the RSTT were 0.09 s and 0.58 s, respectively. To check the criterion-related validity of the RSTT, players performed a repeated linear sprint (RLS and a repeated sprint with changes of direction (RSCD. Significant correlations between the BT and TT of the RLS, RSCD and RSTT were observed (p<0.001. The RSTT is, therefore, a reliable and valid measure of the intermittent repeated sprint agility performance. As this ability is required in all team sports, it is suggested that team sports coaches, fitness coaches and sports scientists consider this test in their training follow-up.

  17. Vertical jumping tests in volleyball: reliability, validity, and playing-position specifics.

    Science.gov (United States)

    Sattler, Tine; Sekulic, Damir; Hadzic, Vedran; Uljevic, Ognjen; Dervisevic, Edvin

    2012-06-01

    Vertical jumping is known to be important in volleyball, and jumping performance tests are frequently studied for their reliability and validity. However, most studies concerning jumping in volleyball have dealt with standard rather than sport-specific jumping procedures and tests. The aims of this study, therefore, were (a) to determine the reliability and factorial validity of 2 volleyball-specific jumping tests, the block jump (BJ) test and the attack jump (AJ) test, relative to 2 frequently used and systematically validated jumping tests, the countermovement jump test and the squat jump test and (b) to establish volleyball position-specific differences in the jumping tests and simple anthropometric indices (body height [BH], body weight, and body mass index [BMI]). The BJ was performed from a defensive volleyball position, with the hands positioned in front of the chest. During an AJ, the players used a 2- to 3-step approach and performed a drop jump with an arm swing followed by a quick vertical jump. A total of 95 high-level volleyball players (all men) participated in this study. The reliability of the jumping tests ranged from 0.97 to 0.99 for Cronbach's alpha coefficients, from 0.93 to 0.97 for interitem correlation coefficients and from 2.1 to 2.8 for coefficients of variation. The highest reliability was found for the specific jumping tests. The factor analysis extracted one significant component, and all of the tests were highly intercorrelated. The analysis of variance with post hoc analysis showed significant differences between 5 playing positions in some of the jumping tests. In general, receivers had a greater jumping capacity, followed by libero players. The differences in jumping capacities should be emphasized vis-a-vis differences in the anthropometric measures of players, where middle hitters had higher BH and body weight, followed by opposite hitters and receivers, with no differences in the BMI between positions.

  18. Reliability of Cognitive Tests of ELSA-Brasil, the Brazilian Longitudinal Study of Adult Health

    Directory of Open Access Journals (Sweden)

    Juliana Alves Batista

    Full Text Available ABSTRACT Cognitive function evaluation entails the use of neuropsychological tests, applied exclusively or in sequence. The results of these tests may be influenced by factors related to the environment, the interviewer or the interviewee. Objectives: We examined the test-retest reliability of some tests of the Brazilian version from the Consortium to Establish a Registry for Alzheimer's disease. Methods: The ELSA-Brasil is a multicentre study of civil servants (35-74 years of age from public institutions across six Brazilian States. The same tests were applied, in different order of appearance, by the same trained and certified interviewer, with an approximate 20-day interval, to 160 adults (51% men, mean age 52 years. The Intraclass Correlation Coefficient (ICC was used to assess the reliability of the measures; and a dispersion graph was used to examine the patterns of agreement between them. Results: We observed higher retest scores in all tests as well as a shorter test completion time for the Trail Making Test B. ICC values for each test were as following: Word List Learning Test (0.56, Word Recall (0.50, Word Recognition (0.35, Phonemic Verbal Fluency Test (VFT, 0.61, Semantic VFT (0.53 and Trail B (0.91. The Bland-Altman plot showed better correlation of executive function (VFT and Trail B than of memory tests. Conclusions: Better performance in retest may reflect a learning effect, and suggest that retest should be repeated using alternate forms or after longer periods. In this sample of adults with high schooling level, reliability was only moderate for memory tests whereas the measurement of executive function proved more reliable.

  19. Research on Wind Turbine Generator Dynamic Reliability Test System Based on Feature Recognition

    Directory of Open Access Journals (Sweden)

    Bin Wang

    2013-09-01

    Full Text Available Wind power resource development is increasingly becoming the focus of the current research and development in various countries' relevant scientific institutions. To make sure the secure and reliable operation of wind turbine generator, the study develops the wind turbine generator dynamic reliability test system. When the fault of gearbox and spindle occurs, their features of vibration signals are special. According to the feature recognition technology, the application of time and frequency domain model identification method has practical significance to the test system. Based on Bayesian network fault diagnosis method, the vibration feature recognition system of wind turbine generator is constructed. Finally, the paper uses GPRS technology to realize the wireless transmission of operation information. The wind turbine generator dynamic reliability test system is built based on GPRS technology to realize automatic control and remote intelligent monitoring and to ensure the safe and stable operation of wind farms.

  20. [Reliability and validity of the modified Allen test: a systematic review and metanalysis].

    Science.gov (United States)

    Romeu-Bordas, Óscar; Ballesteros-Peña, Sendoa

    2017-01-01

    The objective was to evaluate the reliability and validity of the modified Allen test in screening for collateral circulation deficits in the palm and for predicting distal hand ischemia. We performed a systematic review of the literature indexed in 6 databases. We developed a search strategy to locate studies comparing the Allen test to Doppler ultrasound to detect circulation deficits in the hand, studies assessing the incidence of ischemic events on arterial puncture after an abnormal Allen test result, and studies of Allen test interobserver agreement. Fourteen articles met the inclusion criteria. Nine assessed the validity of the test as a screening tool for detecting collateral circulation deficits. From data published in 3 studies that had followed comparable designs we calculated a sensitivity of 77% and specificity of 93% for the Allen test. Four studies that assessed the ability of the test to predict ischemia did not predict any ischemic hand events following arterial puncture in patients with abnormal Allen test results. A single study assessing the test's reliability reported an interobserver agreement rate of 71.5%. This systematic review and metanalysis allows to conclude that the Allen test does not have sufficient diagnostic validity to serve as a screening tool for collateral circulation deficits in the hand. Nor is it a good predictor of hand ischemia after arterial puncture. Moreover, its reliability is limited. There is insufficient evidence to support its systematic use before arterial puncture.

  1. Interrater reliability of mechanical tests for functional classification of transtibial prosthesis components distal to the socket

    Directory of Open Access Journals (Sweden)

    Matthew J. Major, PhD

    2015-08-01

    Full Text Available Substantial evidence suggests that the design and associated mechanical function of lower-limb prostheses affects user health and mobility, supporting common standards of clinical practice for appropriate matching of prosthesis design and user needs. This matching process is dependent on accurate and reliable methods for the functional classification of prosthetic components. The American Orthotic & Prosthetic Association developed a set of tests for L-code characterization of prosthesis mechanical properties to facilitate functional classification of passive below-knee prosthetic components. The mechanical tests require use of test-specific fixtures to be installed in a materials testing machine by a test administrator. Therefore, the purpose of this study was to assess the interrater reliability of test outcomes between two administrators using the same testing facility. Ten prosthetic components (8 feet and 2 pylons that spanned the range of commercial designs were subjected to all appropriate tests. Tests with scalar outcomes demonstrated high interrater reliability (intraclass correlation coefficient (2,1 >/= 0.935, and there was no discrepancy in observation-based outcomes between administrators, suggesting that between-administrator variability may not present a significant source of error. These results support the integration of these mechanical tests for prosthesis classification, which will help enhance objectivity and optimization of the prosthesis-patient matching process for maximizing rehabilitation outcomes.

  2. Interrater reliability of mechanical tests for functional classification of transtibial prosthesis components distal to the socket.

    Science.gov (United States)

    Major, Matthew J; Johnson, William Brett; Gard, Steven A

    2015-01-01

    Substantial evidence suggests that the design and associated mechanical function of lower-limb prostheses affects user health and mobility, supporting common standards of clinical practice for appropriate matching of prosthesis design and user needs. This matching process is dependent on accurate and reliable methods for the functional classification of prosthetic components. The American Orthotic & Prosthetic Association developed a set of tests for L-code characterization of prosthesis mechanical properties to facilitate functional classification of passive below-knee prosthetic components. The mechanical tests require use of test-specific fixtures to be installed in a materials testing machine by a test administrator. Therefore, the purpose of this study was to assess the interrater reliability of test outcomes between two administrators using the same testing facility. Ten prosthetic components (8 feet and 2 pylons) that spanned the range of commercial designs were subjected to all appropriate tests. Tests with scalar outcomes demonstrated high interrater reliability (intraclass correlation coefficient(2,1) >/= 0.935), and there was no discrepancy in observation-based outcomes between administrators, suggesting that between-administrator variability may not present a significant source of error. These results support the integration of these mechanical tests for prosthesis classification, which will help enhance objectivity and optimization of the prosthesis-patient matching process for maximizing rehabilitation outcomes.

  3. Reliability of squat and countermovement jump tests in children 6 to 8 years of age.

    Science.gov (United States)

    Acero, Rafael Martin; Fernández-del Olmo, Miguel; Sánchez, Jose Andres; Otero, Xose Luis; Aguado, Xavier; Rodríguez, Ferran A

    2011-02-01

    The aim of this study was to determine the reliability of the squat jump test (SJ) and countermovement jump test (CMJ), in fifty-six children (30 girls and 26 boys) with ages ranging from 6 to 8 years. Each subject performed two evaluation sessions (T1, T2) with seven days between tests. The results show that the CMJ test has a high intratrial reproducibility in T1 and T2 measured through intraclass correlation coefficient (ICC ≥ 0.95). The ICC for the SJ test had a high value (0.99) only in T1. The variability for both tests among children under 9 years of age is higher than those reported for adult subjects in other studies. The intersession reliability was questionable with a high methodical error (ME= 9.86-15.1%, for the SJ and CMJ, respectively) and a significant worsening of the results of CMJ in T2 (p < .05).

  4. Reliability of the "Ten Test" for assessment of discriminative sensation in hand trauma.

    Science.gov (United States)

    Berger, Michael J; Regan, William R; Seal, Alex; Bristol, Sean G

    2016-10-01

    "Ten Test" (TT) is a bedside measure of discriminative sensation, whereby the magnitude of abnormal sensation to moving light touch is normalized to an area of normal sensation on an 11-point Likert scale (0-10). The purposes of this study were to determine reliability parameters of the TT in a cohort of patients presenting to a hand trauma clinic with subjectively altered sensation post-injury and to compare the reliability of TT to that of the Weinstein Enhanced Sensory Test (WEST). Study participants (n = 29, mean age = 37 ± 12) comprised patients presenting to an outpatient hand trauma clinic with recent hand trauma and self reported abnormal sensation. Participants underwent TT and WEST by two separate raters on the same day. Interrater reliability, response stability and responsiveness of each test were determined by the intraclass correlation coefficient (ICC: 2, 1), standard error of measurement (SEM) with 95% confidence intervals (CI) and minimal detectable difference score, with 95% CI (MDD95), respectively. The TT displayed excellent interrater reliability (ICC = 0.95, 95% CI 0.89-0.97) compared to good reliability for WEST (ICC = 0.78, 95% CI 0.58-0.89). The range of true scores expected with 95% confidence based on the SEM (i.e. response stability), was ±1.1 for TT and ±1.1 for WEST. MDD95 scores reflecting test responsiveness were 1.5 and 1.6 for TT and WEST, respectively. The TT displayed excellent reliability parameters in this patient population. Reliability parameters were stronger for TT compared to WEST. These results provide support for the use of TT as a component of the sensory exam in hand trauma.

  5. Evaluation of accelerated UV and thermal testing for benzene formation in beverages containing benzoate and ascorbic acid.

    Science.gov (United States)

    Nyman, Patricia J; Wamer, Wayne G; Begley, Timothy H; Diachenko, Gregory W; Perfetti, Gracia A

    2010-04-01

    Under certain conditions, benzene can form in beverages containing benzoic and ascorbic acids. The American Beverage Assn. (ABA) has published guidelines to help manufacturers mitigate benzene formation in beverages. These guidelines recommend accelerated testing conditions to test product formulations, because exposure to ultraviolet (UV) light and elevated temperature over the shelf life of the beverage may result in benzene formation in products containing benzoic and ascorbic acids. In this study, the effects of UVA exposure on benzene formation were determined. Benzene formation was examined for samples contained in UV stabilized and non-UV stabilized packaging. Additionally, the usefulness of accelerated thermal testing to simulate end of shelf-life benzene formation was evaluated for samples containing either benzoic or ascorbic acid, or both. The 24 h studies showed that under intense UVA light benzene levels increased by as much as 53% in model solutions stored in non-UV stabilized bottles, whereas the use of UV stabilized polyethylene terephthalate bottles reduced benzene formation by about 13% relative to the non-UV stabilized bottles. Similar trends were observed for the 7 d study. Retail beverages and positive and negative controls were used to study the accelerated thermal testing conditions. The amount of benzene found in the positive controls and cranberry juice suggests that testing at 40 degrees C for 14 d may more reliably simulate end of shelf-life benzene formation in beverages. Except for cranberry juice, retail beverages were not found to contain detectable amounts of benzene (<0.05 ng/g) at the end of their shelf lives.

  6. The long-term reliability of static and dynamic Quantitative Sensory Testing in healthy individuals.

    Science.gov (United States)

    Marcuzzi, Anna; Wrigley, Paul J; Dean, Catherine M; Adams, Roger; Hush, Julia M

    2017-03-21

    Quantitative sensory tests (QST) have been increasingly used to investigate alterations in somatosensory function in a wide range of painful conditions. The interpretation of these findings is based on the assumption that the measures are stable and reproducible. To date, reliability of QST has been investigated for short test-retest intervals. The aim of this study was to investigate the long-term reliability of a multimodal QST assessment in healthy people, with testing conducted on three occasions over 4-months. Forty-two healthy people were enrolled in the study. Static and dynamic tests were performed, including cold and heat pain threshold (CPT, HPT), mechanical wind up (WUR), pressure pain threshold (PPT), two-point discrimination (TPD) and conditioned pain modulation (CPM). Systematic bias, relative reliability and agreement were analysed using repeated measure ANOVA, intraclass correlation coefficients (ICCs3,1) and standard error of the measurement (SEM), respectively. Static QST (CPT, HPT, PPT and TPD) showed good to excellent reliability (ICCs: 0.68 to 0.90). Dynamic QST (WUR and CPM) showed poor to good reliability (ICCs: 0.35 to 0.61). A significant linear decrease over time was observed for mechanical QST at the back (PPT and TPD) and for CPM (p<0.01). Static QST were stable over a period of 4 months; however, a small systematic decrease over time has been observed for mechanical QST. Dynamic QST showed considerable variability over time; in particular, CPM using PPT as the test stimulus did not show adequate reliability, suggesting that this test paradigm may be less useful for monitoring individuals over time.

  7. We need more replication research - A case for test-retest reliability.

    Science.gov (United States)

    Leppink, Jimmie; Pérez-Fuster, Patricia

    2017-06-01

    Following debates in psychology on the importance of replication research, we have also started to see pleas for a more prominent role for replication research in medical education. To enable replication research, it is of paramount importance to carefully study the reliability of the instruments we use. Cronbach's alpha has been the most widely used estimator of reliability in the field of medical education, notably as some kind of quality label of test or questionnaire scores based on multiple items or of the reliability of assessment across exam stations. However, as this narrative review outlines, Cronbach's alpha or alternative reliability statistics may complement but not replace psychometric methods such as factor analysis. Moreover, multiple-item measurements should be preferred above single-item measurements, and when using single-item measurements, coefficients as Cronbach's alpha should not be interpreted as indicators of the reliability of a single item when that item is administered after fundamentally different activities, such as learning tasks that differ in content. Finally, if we want to follow up on recent pleas for more replication research, we have to start studying the test-retest reliability of the instruments we use.

  8. Test - retest reliability of two instruments for measuring public attitudes towards persons with mental illness

    Directory of Open Access Journals (Sweden)

    Leufstadius Christel

    2011-01-01

    Full Text Available Abstract Background Research has identified stigmatization as a major threat to successful treatment of individuals with mental illness. As a consequence several anti-stigma campaigns have been carried out. The results have been discouraging and the field suffers from lack of evidence about interventions that work. There are few reports on psychometric data for instruments used to assess stigma, which thus complicates research efforts. The aim of the present study was to investigate test-retest reliability of the Swedish versions of the questionnaires: FABI and "Changing Minds" and to examine the internal consistency of the two instruments. Method Two instruments, fear and behavioural intentions (FABI and "Changing Minds", used in earlier studies on public attitudes towards persons with mental illness were translated into Swedish and completed by 51 nursing students on two occasions, with an interval of three weeks. Test-retest reliability was calculated by using weighted kappa coefficient and internal consistency using the Cronbach's alpha coefficient. Results Both instruments attain at best moderate test-retest reliability. For the Changing Minds questionnaire almost one fifth (17.9% of the items present poor test-retest reliability and the alpha coefficient for the subscales ranges between 0.19 - 0.46. All of the items in the FABI reach a fair or a moderate agreement between the test and retest, and the questionnaire displays a high internal consistency, alpha 0.80. Conclusions There is a need for development of psychometrically tested instruments within this field of research.

  9. Reliability of functional fitness tests in women from 60 to 80 years

    Directory of Open Access Journals (Sweden)

    Jair Sindra Virtuoso Júnior

    2011-06-01

    Full Text Available The aim of the present study was to verify the reliability expressed by the internal consistency and stability of two series of specific functional fitness tests (AAHPERD and Fullerton in elderly populations. Thirty-six women, mean age 68-year-old, were selected (SD = 6.64. Parameters of functional fitness evaluated were: body strength, flexibility, agility and dynamic balance, coordination, and aerobic endurance. Descriptive statistics were used to analyze the data and describe the sample (frequency, mean and standard deviation, and the intraclass correlation coefficient (ricc was used to verify the concordance between the stability and internal consistency of the tests. Estimated intervals of 95% of reliability was adopted. In general, the two series showed acceptable rates of reliability, the ricc varying from 0.60 to 0.94. Fullerton test proved to be more consistent in the ricc of the proposed tests, mainly in relation to flexibility of the hip and the two-minute-stationary-walking test for the evaluation of aerobic endurance. Results allowed for the conclusion that both series of tests present acceptable levels of reliability.

  10. Reliability of functional fitness tests in women from 60 to 80 years

    Directory of Open Access Journals (Sweden)

    J.S. Virtuoso Júnior

    2011-01-01

    Full Text Available The aim of the present study was to verify the reliability expressed by the internal consistency and stability of two series of specific functional fitness tests (AAHPERD and Fullerton in elderly populations. Thirty-six women, mean age 68-year-old, were selected (SD = 6.64. Parameters of functional fitness evaluated were: body strength, flexibility, agility and dynamic balance, coordination, and aerobic endurance. Descriptive statistics were used to analyze the data and describe the sample (frequency, mean and standard deviation, and the intraclass correlation coefficient (ricc was used to verify the concordance between the stability and internal consistency of the tests. Estimated intervals of 95% of reliability was adopted. In general, the two series showed acceptable rates of reliability, the ricc varying from 0.60 to 0.94. Fullerton test proved to be more consistent in the ricc of the proposed tests, mainly in relation to flexibility of the hip and the two-minute-stationary-walking test for the evaluation of aerobic endurance. Results allowed for the conclusion that both series of tests present acceptable levels of reliability.

  11. The status of failure and reliability testing of artificial blood pumps.

    Science.gov (United States)

    Patel, Sonna M; Throckmorton, Amy L; Untaroiu, Alexandrina; Allaire, Paul E; Wood, Houston G; Olsen, Don B

    2005-01-01

    Artificial blood pumps are today's most promising bridge-to-transplant, bridge-to-recovery, and destination therapy solutions for patients with congestive heart failure. There is a critical need for increased reliability and safety as the next generation of artificial blood pumps approach final development for long-term destination therapy. To date, extensive failure and reliability studies of these devices are considered intellectual property and thus remain unpublished. Presently, the Novacor N100PC, Thoratec VAD, and HeartMate LVAS (IP and XVE) comprise the only four artificial blood pumps commercially available for the treatment of congestive heart failure in the United States. The CardioWest TAH recently received premarket approval from the US Food and Drug Administration. With investigational device exemptions, the AB-180, AbioCor, LionHeart, DeBakey, and Flowmaker are approved for clinical testing. Other blood pumps, such as the American BioMed-Baylor TAH, CorAide, Cleveland Clinic-Nimbus TAH, HeartMate III, Hemadyne, and MagScrew TAH are currently in various stages of mock loop and animal testing, as indicated in published literature. This article extensively reviews in vitro testing, in vivo testing, and the early clinical testing of artificial blood pumps in the United States, as it relates to failure and reliability. This detailed literature review has not been published before and provides a thorough documentation of available data and testing procedures regarding failure and reliability of these various pumps.

  12. Upper Quarter Y Balance Test: reliability and performance comparison between genders in active adults.

    Science.gov (United States)

    Gorman, Paul P; Butler, Robert J; Plisky, Phillip J; Kiesel, Kyle B

    2012-11-01

    The inclusion of movement tests before performance training and sport participation is gaining popularity as part of musculoskeletal screening for injury. The identification of an athlete's asymmetries and poor performance in the preseason allows coaches and sports medicine clinicians the opportunity to proactively address these deficits to reduce the potential for injury. Currently, there are no tests reported in the literature that simultaneously require shoulder and core stability while taking the subjects through a large range of motion at the end range of their stability. Thus, the purpose of this article was to describe the Upper Quarter Y Balance Test and report the gender differences in the performance of the test. Upper extremity reach distances were measured in 95 active adults using a standardized upper extremity balance-and-reach protocol. Intraclass correlation coefficients were used to assess reliability, and gender differences were analyzed using an independent samples t-test, whereas bilateral differences were analyzed using a dependent samples t-test for the normalized composite reach scores. Intraclass correlation coefficient (3.1) for test-retest reliability ranged from 0.80 to 0.99. Intraclass correlation coefficient (3.1) for interrater reliability was 1.00. Average composite scores (right/left) reported as a percentage of limb length were 81.7/82.3% for men and 80.7/80.7% for women. The results of the study suggest that the Upper Quarter Y Balance Test is a reliable test for measuring upper extremity reach distance while in a closed-chain position. It was further determined that there was no significant difference in performance between genders or between sides on the test when normalized to limb length. Coaches and sports medicine professionals may consider incorporating the Upper Quarter Y Balance Test as part of their preprogram testing to identify movement limitations and asymmetries in athletes and thereby may reduce injury.

  13. Reliability and validity of the L test in participants with chronic stroke.

    Science.gov (United States)

    Kim, J S; Chu, D Y; Jeon, H S

    2015-06-01

    Many clinical mobility tests have been used for individuals who have suffered a stroke; however, the ceiling effect has been identified as a limitation for relatively high functioning individuals. The L test, a variation of the timed up and go test (TUG), was developed as a mobility test for patients after amputation. The objective of this study was to examine the reliability and validity of the L test among patients following a stroke. Cross-sectional. Rehabilitation hospital. Thirty-three chronic stroke survivors {20 males and 13 females, mean age 52.4 [standard deviation (SD) 11.2] years; mean time since stroke 29.1 (SD 13.3) months}. Not applicable. Validity was assessed by correlating the L test with other mobility tests (TUG, 10-m walk test and 2-minute walk test). Intra-class correlation coefficients (ICCs) were used to investigate reliability. The minimal detectable change (MDC) was used to determine true change. The L test was strongly correlated with the TUG test (r=0.887), and had excellent intra-rater (ICC3,1=0.99) and inter-rater reliability (ICC2,1=0.99). The MDC with a 95% confidence interval was 4seconds. The L test is a reliable, valid tool for evaluating gait in patients following a stroke. It is a more applicable method to assess individuals who are able to walk greater distances and have better gait in more functional situations. Copyright © 2014 Chartered Society of Physiotherapy. Published by Elsevier Ltd. All rights reserved.

  14. Proof test on thermal and hydraulic design reliability of Japanese PWR fuel assemblies

    Energy Technology Data Exchange (ETDEWEB)

    Akiyama, Mamoru (Univ. of Tokyo (Japan)); Inoue, Akira (Tokyo Institute of Technology (Japan)); Miyazaki, Keiji (Osaka Univ. (Japan)); Abeta, Sadaaki (Mitsubishi, Tokyo (Japan)); Hori, Keiichi (Mitsubishi, Hyogo (Japan)); Mukasa, Tomio; Oishi, Masao; Aoki, Toshimasa; Makihara, Yoshiaki

    1990-01-01

    A series of departure from nucleate boiling (DNB) tests for pressurized water reactors (PWRs) was performed at the Nuclear Power Engineering Test Center. The objective was to prove the reliability of fuel assembly design by confirming the thermal margin of heat transfer. The present method for evaluating the DNB ratio in a Japanese 17 x 17 PWR core is adequate according to the newly obtained DNB test data.

  15. Development of a 20-MeV Dielectric-Loaded Accelerator Test Facility

    CERN Document Server

    Gold, Steven H; Gai, Wei; Hu, Yuan; Jing, Chunguang; Kinkead, Allen; Konecny, Richard; Lin, Y; Nantista, Christopher D; Power, John G; Tang, C; Tantawi, Sami G

    2006-01-01

    This paper will describe a joint project by the Naval Research Laboratory (NRL) and Argonne National Laboratory (ANL), in collaboration with the Stanford Linear Accelerator Center (SLAC), to develop a dielectric-loaded accelerator (DLA) test facility powered by the high-power 11.424-GHz magnicon that was developed by NRL and Omega-P, Inc. The magnicon can presently produce 25 MW of output power in a 250-ns pulse at 10 Hz, and efforts are in progress to increase this to 50 MW.* The facility will include a 5-MeV electron injector being developed by the Accelerator Laboratory of Tsinghua University in Beijing, China. The DLA test structures are being developed by ANL, and some have undergone testing at NRL at gradients up to ~8 MV/m.** SLAC is developing a means to combine the two magnicon output arms, and to drive an injector and accelerator with separate control of the power ratio and relative phase. The installation and testing of the first dielectric-loaded test accelerator, including injector, DLA structure...

  16. Analysis of strain gage reliability in F-100 jet engine testing at NASA Lewis Research Center

    Science.gov (United States)

    Holanda, R.

    1983-01-01

    A reliability analysis was performed on 64 strain gage systems mounted on the 3 rotor stages of the fan of a YF-100 engine. The strain gages were used in a 65 hour fan flutter research program which included about 5 hours of blade flutter. The analysis was part of a reliability improvement program. Eighty-four percent of the strain gages survived the test and performed satisfactorily. A post test analysis determined most failure causes. Five failures were caused by open circuits, three failed gages showed elevated circuit resistance, and one gage circuit was grounded. One failure was undetermined.

  17. Traveling-wave tube reliability estimates, life tests, and space flight experience

    Science.gov (United States)

    Lalli, V. R.; Speck, C. E.

    1977-01-01

    Infant mortality, useful life, and wearout phase of twt life are considered. The performance of existing developmental tubes, flight experience, and sequential hardware testing are evaluated. The reliability history of twt's in space applications is documented by considering: (1) the generic parts of the tube in light of the manner in which their design and operation affect the ultimate reliability of the device, (2) the flight experience of medium power tubes, and (3) the available life test data for existing space-qualified twt's in addition to those of high power devices.

  18. 加速退化试验技术研究、应用与发展%Research, Application and Development of Accelerated Degradation Test Technology

    Institute of Scientific and Technical Information of China (English)

    郑德强; 张正平; 李海波; 吴建国; 徐静

    2011-01-01

    长寿命、高可靠性已经成为工业领域产品的发展目标和要求,对传统的可靠性技术研究提出了新的挑战.加速退化试验技术为长寿命、高可靠产品的寿命和可靠性研究提供了一种有效的途径,成为目前研究的热点.在总结国内外的研究成果的基础上,对加速退化试验的研究背景、试验方法、加速退化模型、工程应用和优化设计等进行了综述和研究,最后分析了加速退化试验的研究现状并展望了后续的研究方向.%Long-lifespan and high-reliability has become the development goal and requirement of industrial products,which brings forwards a new challenge to traditional reliability technologies. Accelerated degradation test technology is an effective approach to evaluate the life and reliability of long-lifespan and high-reliability equipment, and becomes a hot spot of research.Based on analysis of domestic and abroad research achievements, the demand background, testing methods, accelerated degradation models, engineering applications and optimization of accelerated degradation testing were summarized and studied. The main research problems of accelerated degradation test were analyzed and the future development direction was prospected.

  19. Accelerated testing of solid oxide fuel cell stacks for micro combined heat and power application

    DEFF Research Database (Denmark)

    Hagen, Anke; Høgh, Jens Valdemar Thorvald; Barfod, Rasmus

    2015-01-01

    State-of-the-art (SoA) solid oxide fuel cell (SOFC) stacks are tested using profiles relevant for use in micro combined heat and power (CHP) units. Such applications are characterised by dynamic load profiles. In order to shorten the needed testing time and to investigate potential acceleration...

  20. Reliability, usefulness, and validity of a repeated sprint and jump ability test.

    Science.gov (United States)

    Buchheit, Martin; Spencer, Matt; Ahmaidi, Said

    2010-03-01

    Two studies involving 122 handball players were conducted to assess the reliability, usefulness, and validity of a repeated shuttle-sprint and jump ability (RSSJA) test. The test consisted of 6x(2x12.5-m) sprints departing on 25 s, with a countermovement jump performed during recovery between sprints. For the reliability and usefulness study, 14 well-trained male handball players performed the RSSJA test 7 d apart. Reliability of the test variables was assessed by the typical error of measurement, expressed as a coefficient of variation (CV). The minimal changes likely to be "real" in sprint time and jump power were also calculated. For the validity study, players of seven teams (national to international levels, women and men) performed the RSSJA test. CV values for best and mean sprint time were 1.0% (90% CL, 0.7 to 1.6) and 1.0% (90% CL, 0.7 to 1.4). CV values for best and mean jump peak power were 1.7% (90% CL, 1.2 to 2.7) and 1.5% (90% CL, 1.1 to 2.5). The percent sprint and jump decrements were less reliable, with CVs of 22.3% (90% CL, 15.7 to 38.3) and 34.8% (90% CL, 24.2 to 61.8). Minimal changes likely to be "real" for mean sprint time and jumping peak power were -2.6% and 4.8%. Qualitative analysis revealed that the majority of between-team differences were rated as "almost certain" (ie, 100% probability that the true differences were meaningful) for mean sprint and jump performances. The RSSJA test is reliable and valid to assess repeated explosive effort sequences in team sports such as handball. Test results are likely to be representative of gender and competition level; thus the test could be used to discriminate across playing standards and monitor fitness levels.

  1. Reliability and minimal detectable change of the weight-bearing lunge test: A systematic review.

    Science.gov (United States)

    Powden, Cameron J; Hoch, Johanna M; Hoch, Matthew C

    2015-08-01

    Ankle dorsiflexion range of motion (DROM) is often a point of emphasis during the rehabilitation of lower extremity pathologies. With the growing popularity of weight-bearing DROM assessments, several versions of the weight-bearing lunge (WBLT) test have been developed and numerous reliability studies have been conducted. The purpose of this systematic review was to critically appraise and synthesize the studies which examined the reliability and responsiveness of the WBLT to assess DROM. A systematic search of PubMed and EBSCO Host databases from inception to September 2014 was conducted to identify studies whose primary aim was assessing the reliability of the WBLT. The Quality Appraisal of Reliability Studies assessment tool was utilized to determine the quality of included studies. Relative reliability was examined through intraclass correlation coefficients (ICC) and responsiveness was evaluated through minimal detectable change (MDC). A total of 12 studies met the eligibility criteria and were included. Nine included studies assessed inter-clinician reliability and 12 included studies assessed intra-clinician reliability. There was strong evidence that inter-clinician reliability (ICC = 0.80-0.99) as well as intra-clinician reliability (ICC = 0.65-0.99) of the WBLT is good. Additionally, average MDC scores of 4.6° or 1.6 cm for inter-clinician and 4.7° or 1.9 cm for intra-clinician were found, indicating the minimal change in DROM needed to be outside the error of the WBLT. This systematic review determined that the WBLT, regardless of method, can be used clinically to assess DROM as it provides consistent results between one or more clinicians and demonstrates reasonable responsiveness. Copyright © 2015 Elsevier Ltd. All rights reserved.

  2. Familiarization, reliability, and comparability of a 40-m maximal shuttle run test.

    Science.gov (United States)

    Glaister, Mark; Hauck, Hanna; Abraham, Corinne S; Merry, Kevin L; Beaver, Dean; Woods, Bernadette; McInnes, Gillian

    2009-01-01

    The aims of this study were to examine familiarization and reliability associated with a 40-m maximal shuttle run test (40-m MST), and to compare performance measures from the test with those of a typical unidirectional multiple sprint running test (UMSRT). 12 men and 4 women completed four trials of the 40-m MST (8 × 40-m; 20 s rest periods) followed by one trial of a UMSRT (12 × 30-m; repeated every 35 s); with seven days between trials. All trials were conducted indoors and performance times were recorded via twin-beam photocells. Significant between-trial differences in mean 40-m MST times were indicative of learning effects between trials 1 and 2. Test-retest reliability across the remaining trials as determined by coefficient of variation (CV) and intraclass correlation coefficient (ICC) revealed: a) very good reliability for measures of fastest and mean shuttle time (CV = 1.1 - 1.3%; ICC = 0.91 - 0.92); b) good reliability for measures of blood lactate (CV = 10.1 - 23.9%; ICC = 0.74 - 0.82) and ratings of perceived exertion (CV = 5.3 - 7.6%; ICC = 0.79 - 0.84); and c) poor reliability for measures of fatigue (CV = 38.7%; ICC = 0.59). Comparisons between performance indices of the 40-m MST and the UMSRT revealed significant correlations between all measures, except pre-test blood lactate concentration (r = 0. 47). Whilst the 40-m MST does not appear to provide more information than can be gleaned from a typical UMSRT, following the completion of a familiarization trial, the 40-m MST provides an alternative and, except for fatigue measures, reliable means of evaluating repeated sprint ability. Key pointsTests of multiple sprint performance are a popular means of evaluating repeated sprint ability.Multiple sprint tests incorporating changes of direction may be more ecologically valid than unidirectional protocols.The 40-m maximal shuttle run test is a reliable way of evaluating repeated sprint ability following the completion of one familiarization trial

  3. FAMILIARIZATION, RELIABILITY, AND COMPARABILITY OF A 40-M MAXIMAL SHUTTLE RUN TEST

    Directory of Open Access Journals (Sweden)

    Mark Glaister

    2009-03-01

    Full Text Available The aims of this study were to examine familiarization and reliability associated with a 40-m maximal shuttle run test (40-m MST, and to compare performance measures from the test with those of a typical unidirectional multiple sprint running test (UMSRT. 12 men and 4 women completed four trials of the 40-m MST (8 × 40-m; 20 s rest periods followed by one trial of a UMSRT (12 × 30-m; repeated every 35 s; with seven days between trials. All trials were conducted indoors and performance times were recorded via twin-beam photocells. Significant between-trial differences in mean 40-m MST times were indicative of learning effects between trials 1 and 2. Test-retest reliability across the remaining trials as determined by coefficient of variation (CV and intraclass correlation coefficient (ICC revealed: a very good reliability for measures of fastest and mean shuttle time (CV = 1.1 - 1.3%; ICC = 0.91 - 0.92; b good reliability for measures of blood lactate (CV = 10.1 - 23.9%; ICC = 0.74 - 0.82 and ratings of perceived exertion (CV = 5.3 - 7.6%; ICC = 0.79 - 0.84; and c poor reliability for measures of fatigue (CV = 38.7%; ICC = 0.59. Comparisons between performance indices of the 40-m MST and the UMSRT revealed significant correlations between all measures, except pre-test blood lactate concentration (r = 0. 47. Whilst the 40-m MST does not appear to provide more information than can be gleaned from a typical UMSRT, following the completion of a familiarization trial, the 40-m MST provides an alternative and, except for fatigue measures, reliable means of evaluating repeated sprint ability

  4. Statistical Degradation Models for Reliability Analysis in Non-Destructive Testing

    Science.gov (United States)

    Chetvertakova, E. S.; Chimitova, E. V.

    2017-04-01

    In this paper, we consider the application of the statistical degradation models for reliability analysis in non-destructive testing. Such models enable to estimate the reliability function (the dependence of non-failure probability on time) for the fixed critical level using the information of the degradation paths of tested items. The most widely used models are the gamma and Wiener degradation models, in which the gamma or normal distributions are assumed as the distribution of degradation increments, respectively. Using the computer simulation technique, we have analysed the accuracy of the reliability estimates, obtained for considered models. The number of increments can be enlarged by increasing the sample size (the number of tested items) or by increasing the frequency of measuring degradation. It has been shown, that the sample size has a greater influence on the accuracy of the reliability estimates in comparison with the measuring frequency. Moreover, it has been shown that another important factor, influencing the accuracy of reliability estimation, is the duration of observing degradation process.

  5. An empirical look at the Defense Mechanism Test (DMT): reliability and construct validity.

    Science.gov (United States)

    Ekehammar, Bo; Zuber, Irena; Konstenius, Marja-Liisa

    2005-07-01

    Although the Defense Mechanism Test (DMT) has been in use for almost half a century, there are still quite contradictory views about whether it is a reliable instrument, and if so, what it really measures. Thus, based on data from 39 female students, we first examined DMT inter-coder reliability by analyzing the agreement among trained judges in their coding of the same DMT protocols. Second, we constructed a "parallel" photographic picture that retained all structural characteristic of the original and analyzed DMT parallel-test reliability. Third, we examined the construct validity of the DMT by (a) employing three self-report defense-mechanism inventories and analyzing the intercorrelations between DMT defense scores and corresponding defenses in these instruments, (b) studying the relationships between DMT responses and scores on trait and state anxiety, and (c) relating DMT-defense scores to measures of self-esteem. The main results showed that the DMT can be coded with high reliability by trained coders, that the parallel-test reliability is unsatisfactory compared to traditional psychometric standards, that there is a certain generalizability in the number of perceptual distortions that people display from one picture to another, and that the construct validation provided meager empirical evidence for the conclusion that the DMT measures what it purports to measure, that is, psychological defense mechanisms.

  6. Test-Retest Reliability of the Dual-Microphone Voice Range Profile.

    Science.gov (United States)

    Printz, Trine; Sorensen, Jesper Roed; Godballe, Christian; Grøntved, Ågot Møller

    2017-05-16

    The voice range profile (VRP) measures vocal intensity and fundamental frequency. Phonosurgical and logopedic treatment outcome studies using the VRP report voice improvements of 3-6 semitones (ST) in ST range and 4-7 decibels (dB) in sound pressure level range after treatment. These small improvements stress the importance of reliable measurements. The aim was to evaluate the test-retest reliability of the dual-microphone computerized VRP on participants with healthy voices. This is a prospective test-retest reliability study. Dual-microphone VRPs were repeated twice on healthy participants (n = 37) with an interval of 6-37 days. Voice frequency and intensity (minimum, maximum, and ranges) were assessed in combination with the area of the VRP. Correlations between VRP parameters were high (r > 0.60). However, in the retest, a statistically significant increase in voice frequency range (1.4 ST [95% confidence interval {CI}: 0.8-2.1 ST], P VRP (148 cells [95% CI: 87-210 cells], P VRP is well below the differences seen after surgical or logopedic intervention, even when measuring in non-sound-treated rooms. There is a need for studies regarding inter-examiner reliability with a longer interval between test and retest before the assessment is fully reliable for clinical application. Copyright © 2016 The Authors. Published by Elsevier Inc. All rights reserved.

  7. Reliability and smallest worthwhile difference of the NFL-225 test in NCAA Division I football players.

    Science.gov (United States)

    Mann, J Bryan; Ivey, Pat J; Brechue, William F; Mayhew, Jerry L

    2014-05-01

    The NFL-225 test is widely used to assess the strength level and evaluate the progress of college football players during resistance training. Despite the studies evaluating the validity of this test, there are no reports assessing its reliability. The purpose of this study was to determine the reliability and smallest worthwhile difference (SWD) of the NFL-225 test in Division I college football players. Seventy-two players were assessed for more than 3 weeks for the number of repetitions completed with a constant load of 102.3 kg (225 lbs) during winter conditioning. Test sessions occurred on the same day and at the same time 1 week apart. Intraclass correlation coefficients (ICCs) between weeks 1 and 2 (ICC = 0.987), weeks 2 and 3 (ICC = 0.981), and across weeks 1, 2, and 3 (ICC = 0.988) indicated high relative reliability. A small technical error (TE) (TE = 0.5 repetitions) provided strong absolute reliability. The SWD suggests that a change in performance of 3 repetitions or more after training would indicate a meaningful improvement in performance for this test.

  8. Reliability and validity of the Korean version of the internet addiction test among college students.

    Science.gov (United States)

    Lee, Kounseok; Lee, Hye-Kyung; Gyeong, Hyunsu; Yu, Byeongkwan; Song, Yul-Mai; Kim, Daeho

    2013-05-01

    We developed a Korean translation of the Internet Addiction Test (KIAT), widely used self-report for internet addiction and tested its reliability and validity in a sample of college students. Two hundred seventy-nine college students at a national university completed the KIAT. Internal consistency and two week test-retest reliability were calculated from the data, and principal component factor analysis was conducted. Participants also completed the Internet Addiction Diagnostic Questionnaire (IADQ), the Korea Internet addiction scale (K-scale), and the Patient Health Questionnaire-9 for the criterion validity. Cronbach's alpha of the whole scale was 0.91, and test-retest reliability was also good (r = 0.73). The IADQ, the K-scale, and depressive symptoms were significantly correlated with the KIAT scores, demonstrating concurrent and convergent validity. The factor analysis extracted four factors (Excessive use, Dependence, Withdrawal, and Avoidance of reality) that accounted for 59% of total variance. The KIAT has outstanding internal consistency and high test-retest reliability. Also, the factor structure and validity data show that the KIAT is comparable to the original version. Thus, the KIAT is a psychometrically sound tool for assessing internet addiction in the Korean-speaking population.

  9. Reliability of specific on-ice repeated-sprint ability test for ice-hockey players

    Directory of Open Access Journals (Sweden)

    Karel Hůlka

    2014-06-01

    Full Text Available Background: Repeated sprint ability tests are today widely used to evaluate the performance capability in team sports. Objective: The aim of this study was to determine the reliability of a specific ice hockey test, which indicates the agility and repeated-sprint ability of the players. Methods: Twenty four highly trained junior ice hockey players (age = 17.68 ± 1.52 years; BMI = 23.8 ± 1.92 kg . m-2 participated in the study. Each participant was assessed for specific on-ice repeated-sprint ability test 12 × 54 m with 30 s rest. Intraclass correlation coefficient (association between two repeated measurements and coefficient of variation were calculated to assess the reliability of the test. Results: All intraclass correlation coefficients were .78 for sprint decrement and .98 for total time and the best time, the coefficient of variation was 1.52% for best sprint time, 1.31% for total time and 19.3% for sprint decrement variable. Conclusions: The results suggest the high reliability of the ice hockey agility test expressed by the best sprint time and repeated-sprint ability by the total time and less reliability of sprint decrement.

  10. Reliability of Health-Related Physical Fitness Tests among Colombian Children and Adolescents: The FUPRECOL Study.

    Directory of Open Access Journals (Sweden)

    Robinson Ramírez-Vélez

    Full Text Available Substantial evidence indicates that youth physical fitness levels are an important marker of lifestyle and cardio-metabolic health profiles and predict future risk of chronic diseases. The reliability physical fitness tests have not been explored in Latino-American youth population. This study's aim was to examine the reliability of health-related physical fitness tests that were used in the Colombian health promotion "Fuprecol study". Participants were 229 Colombian youth (boys n = 124 and girls n = 105 aged 9 to 17.9 years old. Five components of health-related physical fitness were measured: 1 morphological component: height, weight, body mass index (BMI, waist circumference, triceps skinfold, subscapular skinfold, and body fat (% via impedance; 2 musculoskeletal component: handgrip and standing long jump test; 3 motor component: speed/agility test (4x10 m shuttle run; 4 flexibility component (hamstring and lumbar extensibility, sit-and-reach test; 5 cardiorespiratory component: 20-meter shuttle-run test (SRT to estimate maximal oxygen consumption. The tests were performed two times, 1 week apart on the same day of the week, except for the SRT which was performed only once. Intra-observer technical errors of measurement (TEMs and inter-rater (reliability were assessed in the morphological component. Reliability for the Musculoskeletal, motor and cardiorespiratory fitness components was examined using Bland-Altman tests. For the morphological component, TEMs were small and reliability was greater than 95% of all cases. For the musculoskeletal, motor, flexibility and cardiorespiratory components, we found adequate reliability patterns in terms of systematic errors (bias and random error (95% limits of agreement. When the fitness assessments were performed twice, the systematic error was nearly 0 for all tests, except for the sit and reach (mean difference: -1.03% [95% CI = -4.35% to -2.28%]. The results from this study indicate that the

  11. Reliability of Health-Related Physical Fitness Tests among Colombian Children and Adolescents: The FUPRECOL Study.

    Science.gov (United States)

    Ramírez-Vélez, Robinson; Rodrigues-Bezerra, Diogo; Correa-Bautista, Jorge Enrique; Izquierdo, Mikel; Lobelo, Felipe

    2015-01-01

    Substantial evidence indicates that youth physical fitness levels are an important marker of lifestyle and cardio-metabolic health profiles and predict future risk of chronic diseases. The reliability physical fitness tests have not been explored in Latino-American youth population. This study's aim was to examine the reliability of health-related physical fitness tests that were used in the Colombian health promotion "Fuprecol study". Participants were 229 Colombian youth (boys n = 124 and girls n = 105) aged 9 to 17.9 years old. Five components of health-related physical fitness were measured: 1) morphological component: height, weight, body mass index (BMI), waist circumference, triceps skinfold, subscapular skinfold, and body fat (%) via impedance; 2) musculoskeletal component: handgrip and standing long jump test; 3) motor component: speed/agility test (4x10 m shuttle run); 4) flexibility component (hamstring and lumbar extensibility, sit-and-reach test); 5) cardiorespiratory component: 20-meter shuttle-run test (SRT) to estimate maximal oxygen consumption. The tests were performed two times, 1 week apart on the same day of the week, except for the SRT which was performed only once. Intra-observer technical errors of measurement (TEMs) and inter-rater (reliability) were assessed in the morphological component. Reliability for the Musculoskeletal, motor and cardiorespiratory fitness components was examined using Bland-Altman tests. For the morphological component, TEMs were small and reliability was greater than 95% of all cases. For the musculoskeletal, motor, flexibility and cardiorespiratory components, we found adequate reliability patterns in terms of systematic errors (bias) and random error (95% limits of agreement). When the fitness assessments were performed twice, the systematic error was nearly 0 for all tests, except for the sit and reach (mean difference: -1.03% [95% CI = -4.35% to -2.28%]. The results from this study indicate that the "Fuprecol

  12. Reliability of Health-Related Physical Fitness Tests among Colombian Children and Adolescents: The FUPRECOL Study

    Science.gov (United States)

    Ramírez-Vélez, Robinson; Rodrigues-Bezerra, Diogo; Correa-Bautista, Jorge Enrique; Izquierdo, Mikel; Lobelo, Felipe

    2015-01-01

    Substantial evidence indicates that youth physical fitness levels are an important marker of lifestyle and cardio-metabolic health profiles and predict future risk of chronic diseases. The reliability physical fitness tests have not been explored in Latino-American youth population. This study’s aim was to examine the reliability of health-related physical fitness tests that were used in the Colombian health promotion “Fuprecol study”. Participants were 229 Colombian youth (boys n = 124 and girls n = 105) aged 9 to 17.9 years old. Five components of health-related physical fitness were measured: 1) morphological component: height, weight, body mass index (BMI), waist circumference, triceps skinfold, subscapular skinfold, and body fat (%) via impedance; 2) musculoskeletal component: handgrip and standing long jump test; 3) motor component: speed/agility test (4x10 m shuttle run); 4) flexibility component (hamstring and lumbar extensibility, sit-and-reach test); 5) cardiorespiratory component: 20-meter shuttle-run test (SRT) to estimate maximal oxygen consumption. The tests were performed two times, 1 week apart on the same day of the week, except for the SRT which was performed only once. Intra-observer technical errors of measurement (TEMs) and inter-rater (reliability) were assessed in the morphological component. Reliability for the Musculoskeletal, motor and cardiorespiratory fitness components was examined using Bland–Altman tests. For the morphological component, TEMs were small and reliability was greater than 95% of all cases. For the musculoskeletal, motor, flexibility and cardiorespiratory components, we found adequate reliability patterns in terms of systematic errors (bias) and random error (95% limits of agreement). When the fitness assessments were performed twice, the systematic error was nearly 0 for all tests, except for the sit and reach (mean difference: -1.03% [95% CI = -4.35% to -2.28%]. The results from this study indicate that the

  13. The graded cycling test combined with the talk test is reliable for patients with ischemic heart disease

    DEFF Research Database (Denmark)

    Nielsen, Susanne Grøn; Buus, Lise; Hage, Tine

    2014-01-01

    PURPOSE: To assess relative reliability and measurement error of the Graded Cycling Test (GCT) with the Talk Test (TT) for patients with cardiac disease. METHODS: Patients (N = 64; women, n = 30) with ischemic heart disease performed the GCT with the TT twice in 1 day. Every minute the patient...... with cardiac disease in clinical settings with small measurement error and an excellent relative reliability. These results apply to both patient-rated and PT-rated TT.......)2.1 and absolute reliability: standard error of measurement with 95% CI (SEM95) and smallest real difference (SRD) were calculated. RESULTS: Intraclass correlation coefficient values of 0.90, 0.91, and 0.90 were observed for TT+, TT±, and TT-, respectively. Physiotherapist ICCs ranged between 0...

  14. Concept, implementation and commissioning of the automation system for the accelerator module test facility AMTF

    Energy Technology Data Exchange (ETDEWEB)

    Böckmann, Torsten A.; Korth, Olaf; Clausen, Matthias; Schoeneburg, Bernd [MKS, Deutsches Elektronen Synchrotron DESY, 22607 Hamburg (Germany)

    2014-01-29

    The European XFEL project launched on June 5, 2007 will require about 103 accelerator modules as a main part of the XFEL linear accelerator. All superconducting components constituting the accelerator module like cavities and magnets have to be tested before the assembly. For the tests of the individual cavities and the complete modules an XFEL Accelerator Module Test Facility (AMTF) has been erected at DESY. The process control system EPICS (Experimental Physics and Industrial Control System) is used to control and operate the cryogenic plant and all its subcomponents. A complementary component of EPICS is the Open Source software suit CSS (Control System Studio). CSS is an integrated engineering, maintenance and operating tool for EPICS. CSS enables local and remote operating and monitoring of the complete system and thus represents the human machine interface. More than 250 PROFIBUS nodes work at the accelerator module test facility. DESY installed an extensive diagnostic and condition monitoring system. With these diagnostic tools it is possible to examine the correct installation and configuration of all PROFIBUS nodes in real time. The condition monitoring system based on FDT/DTM technology shows the state of the PROFIBUS devices at a glance. This information can be used for preventive maintenance which is mandatory for continuous operation of the AMTF facility. The poster will describe all steps form engineering to implementation and commissioning.

  15. An Evaluation of High Frequency Acceleration Test at XLPE Cable’s Insulator

    Science.gov (United States)

    Iwasaki, Kimihiro; Nakade, Masahiko; Tanaka, Atsushi; Tanimoto, Mihoko; Okashita, Minoru; Ito, Kazumi

    We investigated whether a high frequency acceleration method has validity at the degradation of XLPE in case of no influence of water for realizing a lifetime test at near the operating electric field. The tests was carried out at 50Hz, 1000Hz, and 3000Hz frequency using Recessed specimen and the specimen under Needle-plane electrode system, time-to-breakdown was measured. A clear property of frequency acceleration was checked in both results of tests, and the validity of the frequency acceleration technique was shown. And we realize that frequency acceleration factor is lower than the frequency ratio at both tests of specimens. We think the reason is that the amount of accumulation of the space charge per cycle at a defect or a tree tip at high frequency is less than the accumulation at 50Hz. Moreover, tree growth time effects at the time to breakdown of Needle-plane system specimen, but it effects a little at Recessed specimen, so there is difference of acceleration rate between both specimens. The lifetime exponent of V-t characteristic, n, increases at a 3000Hz examination, so it is suggested that n has a frequency dependence.

  16. Concept, implementation and commissioning of the automation system for the accelerator module test facility AMTF

    Science.gov (United States)

    Böckmann, Torsten A.; Korth, Olaf; Clausen, Matthias; Schoeneburg, Bernd

    2014-01-01

    The European XFEL project launched on June 5, 2007 will require about 103 accelerator modules as a main part of the XFEL linear accelerator. All superconducting components constituting the accelerator module like cavities and magnets have to be tested before the assembly. For the tests of the individual cavities and the complete modules an XFEL Accelerator Module Test Facility (AMTF) has been erected at DESY. The process control system EPICS (Experimental Physics and Industrial Control System) is used to control and operate the cryogenic plant and all its subcomponents. A complementary component of EPICS is the Open Source software suit CSS (Control System Studio). CSS is an integrated engineering, maintenance and operating tool for EPICS. CSS enables local and remote operating and monitoring of the complete system and thus represents the human machine interface. More than 250 PROFIBUS nodes work at the accelerator module test facility. DESY installed an extensive diagnostic and condition monitoring system. With these diagnostic tools it is possible to examine the correct installation and configuration of all PROFIBUS nodes in real time. The condition monitoring system based on FDT/DTM technology shows the state of the PROFIBUS devices at a glance. This information can be used for preventive maintenance which is mandatory for continuous operation of the AMTF facility. The poster will describe all steps form engineering to implementation and commissioning.

  17. Validity and Reliability of an English Test Paper in Junior Middle School

    Institute of Scientific and Technical Information of China (English)

    轩慧芳

    2012-01-01

      Test plays an important role in our lives in that it can cause backwash towards our teaching and learning. Thus the pur⁃pose of the present study is to examine the quality of an English test paper in a junior middle school of Urumqi according to the language test theories. Through the data collection and analyses, the results indicate that the test paper is a medium-level test and the reliability is suitable. From the correlation analysis, we can see that each part has a high correlation value to the total, indicat⁃ing that all of them contribute to generate language proficiency.

  18. Accelerated tests for the soft error rate determination of single radiation particles in components of terrestrial and avionic electronic systems; Tests acceleres pour la determination du taux d'erreurs induits par les particules uniques pour les composants des systemes electroniques terrestres et aeronautiques

    Energy Technology Data Exchange (ETDEWEB)

    Flament, O. [CEA Bruyeres-le-Chatel, DIF, 91 (France); Baggio, J. [CESTA - CEA Centre d' Etudes Scientifiques et Techniques d' Aquitaine, 33 - Le Barp (France)

    2010-03-15

    This paper describes the main features of the accelerated test procedures used to determine reliability data of microelectronics devices used in terrestrial environment.This paper focuses on the high energy particle test that could be performed through spallation neutron source or quasi-mono-energetic neutron or proton. Improvements of standards are illustrated with respect to the state of the art of knowledge in radiation effects and scaling down of microelectronics technologies. (authors)

  19. Publishing nutrition research: validity, reliability, and diagnostic test assessment in nutrition-related research.

    Science.gov (United States)

    Gleason, Philip M; Harris, Jeffrey; Sheean, Patricia M; Boushey, Carol J; Bruemmer, Barbara

    2010-03-01

    This is the sixth in a series of monographs on research design and analysis. The purpose of this article is to describe and discuss several concepts related to the measurement of nutrition-related characteristics and outcomes, including validity, reliability, and diagnostic tests. The article reviews the methodologic issues related to capturing the various aspects of a given nutrition measure's reliability, including test-retest, inter-item, and interobserver or inter-rater reliability. Similarly, it covers content validity, indicators of absolute vs relative validity, and internal vs external validity. With respect to diagnostic assessment, the article summarizes the concepts of sensitivity and specificity. The hope is that dietetics practitioners will be able to both use high-quality measures of nutrition concepts in their research and recognize these measures in research completed by others.

  20. Sport-Specific Motor Fitness Tests in Water Polo: Reliability, Validity and Playing Position Differences

    Directory of Open Access Journals (Sweden)

    Ognjen Uljevic

    2013-12-01

    Full Text Available Sport-specific motor fitness tests are not often examined in water polo. In this study we examined the reliability, factorial and discriminative validity of 10 water-polo-specific motor-fitness tests, namely: three tests of in-water jumps (thrusts, two characteristic swimming sprints (10 and 20 metres from the water start, three ball-throws (shoots, one test of passing precision (accuracy, and a test of the dynamometric force produced while using the eggbeater kick. The sample of subjects consisted of 54 young male water polo players (15 to 17 years of age; 1.86 ± 0.07 m, and 83.1 ± 9.9 kg. All tests were applied over three testing trials. Reliability analyses included Cronbach Alpha coefficients (CA, inter-item- correlations (IIR and coefficients of the variation (CV, while an analysis of variance was used to define any systematic bias between the testing trials. All tests except the test of accuracy (precision were found to be reliable (CA ranged from 0.83 to 0.97; IIR from 0.62 to 0.91; CV from 2% to 21%; with small and irregular biases between the testing trials. Factor analysis revealed that jumping capacities as well as throwing and sprinting capacities should be observed as a relatively independent latent dimensions among young water polo players. Discriminative validity of the applied tests is partially proven since the playing positions significantly (p < 0.05 differed in some of the applied tests, with the points being superior in their fitness capacities in comparison to their teammates. This study included players from one of the world’s best junior National leagues, and reported values could be used as fitness standards for such an age. Further studies are needed to examine the applicability of the proposed test procedures to older subjects and females.

  1. [Attempt for development of rapid word reading test for children--evaluation of reliability and validity].

    Science.gov (United States)

    Hashimoto, Ryusaku; Kashiwagi, Mitsuru; Suzuki, Shuhei

    2008-09-01

    We developed a rapid word reading test for examining the phonological processing ability of Japanese children. We prepared two versions of the test, version A and B. Each test has word and non-word tasks. Twenty-two healthy boys of third grade in primary schools participated in this validation study. For criterion related validity, we performed the serial Hiragana reading test, the sentence reading test, Raven's coloured progressive matrices (RCPM), the Token test for children, the Kana word dictation test, the standardized comprehension test of abstract words (SCTAW), and Trail Circle test. The reading times of the newly developed test correlated moderately or highly with those of the serial Hiragana reading test and the sentence reading test. However, the scores of the other tests (RCPM, Token test for children, Kana word dictation test, SCTAW, Trail Circle test) did not correlated with the reading time of the rapid word reading test. Test-retest reliabilities in the word tasks were more than moderate: 0.52 and 0.76 in versions A and B, while those in the non-word tasks were high: 0.91 and 0.88 in versions A and B. The correlation coefficient between versions A and B was 0.7 for the word tasks and 0.92 for the non-word tasks. This study showed that the rapid word reading test has substantial validity and reliability for testing the phonological processing ability of Japanese children. In addition, the non-word tasks were more suitable for selectively examining the speed of the grapheme to phoneme conversion process.

  2. Test-retest reliability of a questionnaire measuring perceptions of neighborhood food environment.

    Science.gov (United States)

    Ma, Xiaoguang; Barnes, Timothy L; Freedman, Darcy A; Bell, Bethany A; Colabianchi, Natalie; Liese, Angela D

    2013-05-01

    There is a lack of validated and reliable instruments on perception of the food environment, in particular for rural environments. We estimated the test-retest reliability of a questionnaire assessing perceptions of the food environment. A total of 101 primary food shoppers in South Carolina were interviewed by phone to assess their perceptions of the food environment and presence of different food outlet types in their neighborhood. The survey was repeated approximately one month after the initial administration. The intra-class correlation (ICC) and Phi coefficient are reported as measures of reliability. The majority of questions on perceptions of the neighborhood food environment appear highly reliable (ICCs range from 0.55 to 0.71), including the 3-item scale on healthy food availability (ICC 0.71). Compared to participants in rural areas, those in urban areas demonstrated better reliability for questions on opportunities to purchase fast food and perceived presence of a supercenter. More research is needed to evaluate potential rural-urban differences in reliability.

  3. Virtual accelerator concept, implementation and preliminary test; Accelerateur virtuel Concept, implementation et premier test

    Energy Technology Data Exchange (ETDEWEB)

    Uriot, D.; Duperrier, R

    2006-05-15

    A virtual accelerator is the coupling of a simulation code with the control system of a real machine. 3 operating modes are considered. First, the monitoring mode in which any action on the control system has an impact on both real and virtual machines. This mode allows a direct comparison between simulation results and the real behaviour of the accelerator. Secondly, the flight simulation mode, this mode allows the accelerator operators to simulate the effect of any change in the parameters of the control system before transferring them to the real machine. The main advantage of this mode is to allow the assessment of operating procedures before implementing them on the real machine. The third mode is the automatic steering mode in which the simulation code assumes the reins of the control system of the real machine. This mode allows the making of complex and time-consuming adjustment procedures in an automatic way. TraceWin is a simulation code dedicated to the behaviour of charged-particle beams in a linear accelerator. TraceWin is consistent with the EPICS technology on which the control system of most accelerators is based. A virtual accelerator composed of the SILHI injector combined to the TraceWin code via the EPICS environment has showed its efficiency in the automatic steering mode. (A.C.)

  4. Investigation of Gallium Nitride Transistor Reliability through Accelerated Life Testing and Modeling

    Science.gov (United States)

    2011-12-01

    appreciated my associations with classmates and friends: Ben Crossley, Derrick Langley, Will Cobb, Neal Kraft , Scott Callihan, Dane Fuller, Kurt... saturation region, when VD ≥ (VG – VT), the drain current is 2( ) ( ) 2 ( )D G T W xI V V L d d      . (8) Typical drain current versus...The unity current gain cut-off frequency is sat T gs g gd vf L L L    (11) where vsat is the saturation velocity of the narrow bandgap

  5. Reliability of the one-repetition-maximum power clean test in adolescent athletes.

    Science.gov (United States)

    Faigenbaum, Avery D; McFarland, James E; Herman, Robert E; Naclerio, Fernando; Ratamess, Nicholas A; Kang, Jie; Myer, Gregory D

    2012-02-01

    Although the power clean test is routinely used to assess strength and power performance in adult athletes, the reliability of this measure in younger populations has not been examined. Therefore, the purpose of this study was to determine the reliability of the 1-repetition maximum (1RM) power clean in adolescent athletes. Thirty-six male athletes (age 15.9 ± 1.1 years, body mass 79.1 ± 20.3 kg, height 175.1 ±7.4 cm) who had >1 year of training experience in weightlifting exercises performed a 1RM power clean on 2 nonconsecutive days in the afternoon following standardized procedures. All test procedures were supervised by a senior level weightlifting coach and consisted of a systematic progression in test load until the maximum resistance that could be lifted for 1 repetition using proper exercise technique was determined. Data were analyzed using an intraclass correlation coefficient (ICC[2,k]), Pearson correlation coefficient (r), repeated measures analysis of variance, Bland-Altman plot, and typical error analyses. Analysis of the data revealed that the test measures were highly reliable demonstrating a test-retest ICC of 0.98 (95% confidence interval = 0.96-0.99). Testing also demonstrated a strong relationship between 1RM measures in trials 1 and 2 (r = 0.98, p adolescent athletes when standardized testing procedures are followed and qualified instruction is present.

  6. RELIABILITY OF THE ONE REPETITION-MAXIMUM POWER CLEAN TEST IN ADOLESCENT ATHLETES

    Science.gov (United States)

    Faigenbaum, Avery D.; McFarland, James E.; Herman, Robert; Naclerio, Fernando; Ratamess, Nicholas A.; Kang, Jie; Myer, Gregory D.

    2013-01-01

    Although the power clean test is routinely used to assess strength and power performance in adult athletes, the reliability of this measure in younger populations has not been examined. Therefore, the purpose of this study was to determine the reliability of the one repetition maximum (1 RM) power clean in adolescent athletes. Thirty-six male athletes (age 15.9 ± 1.1 yrs, body mass 79.1 ± 20.3 kg, height 175.1 ±7.4 cm) who had more than 1 year of training experience with weightlifting exercises performed a 1 RM power clean on two nonconsecutive days in the afternoon following standardized procedures. All test procedures were supervised by a senior level weightlifting coach and consisted of a systematic progression in test load until the maximum resistance that could be lifted for one repetition using proper exercise technique was determined. Data were analyzed using an intraclass correlation coefficient (ICC [2,k]), Pearson correlation coefficient (r), repeated measures ANOVA, Bland-Altman plot, and typical error analyses. Analysis of the data revealed that the test measures were highly reliable demonstrating a test-retest ICC of 0.98 (95% CI = 0.96–0.99). Testing also demonstrated a strong relationship between 1 RM measures on trial 1 and trial 2 (r=0.98, padolescent athletes when standardized testing procedures are followed and qualified instruction is present. PMID:22233786

  7. Full-Scale Accelerated Pavement Testing of Warm-Mix Asphalt (WMA) for Airfield Pavements

    Science.gov (United States)

    2014-01-01

    ER D C/ G SL T R -1 4 -3 Full-Scale Accelerated Pavement Testing of Warm-Mix Asphalt (WMA) for Airfield Pavements G eo te ch n ic al...2014 Full-Scale Accelerated Pavement Testing of Warm-Mix Asphalt (WMA) for Airfield Pavements Mariely Mejías-Santiago, Jesse D. Doyle, and John F... asphalt (WMA) mixtures designed for airfield pavements. Three WMA mixtures were evaluated and compared to a control hot-mix asphalt (HMA) mixture. Data

  8. Status and Plans for a Superconducting RF Accelerator Test Facility at Fermilab

    CERN Document Server

    Leibfritz, J; Baffes, C M; Carlson, K; Chase, B; Church, M D; Harms, E R; Klebaner, A L; Kucera, M; Martinez, A; Nagaitsev, S; Nobrega, L E; Piot, P; Reid, J; Wendt, M; Wesseln, S J

    2013-01-01

    The Advanced Superconducting Test Acccelerator (ASTA) is being constructed at Fermilab. The existing New Muon Lab (NML) building is being converted for this facility. The accelerator will consist of an electron gun, injector, beam acceleration section consisting of 3 TTF-type or ILC-type cryomodules, multiple downstream beamlines for testing diagnostics and conducting various beam tests, and a high power beam dump. When completed, it is envisioned that this facility will initially be capable of generating a 750-MeV electron beam with ILC beam intensity. An expansion of this facility was recently completed that will provide the capability to upgrade the accelerator to a total beam energy of 1.5-GeV. Two new buildings were also constructed adjacent to the ASTA facility to house a new cryogenic plant and multiple superconducting RF (SRF) cryomodule test stands. In addition to testing accelerator components, this facility will be used to test RF power systems, instrumentation, and control systems for future SRF a...

  9. A testing-coverage software reliability model considering fault removal efficiency and error generation.

    Science.gov (United States)

    Li, Qiuying; Pham, Hoang

    2017-01-01

    In this paper, we propose a software reliability model that considers not only error generation but also fault removal efficiency combined with testing coverage information based on a nonhomogeneous Poisson process (NHPP). During the past four decades, many software reliability growth models (SRGMs) based on NHPP have been proposed to estimate the software reliability measures, most of which have the same following agreements: 1) it is a common phenomenon that during the testing phase, the fault detection rate always changes; 2) as a result of imperfect debugging, fault removal has been related to a fault re-introduction rate. But there are few SRGMs in the literature that differentiate between fault detection and fault removal, i.e. they seldom consider the imperfect fault removal efficiency. But in practical software developing process, fault removal efficiency cannot always be perfect, i.e. the failures detected might not be removed completely and the original faults might still exist and new faults might be introduced meanwhile, which is referred to as imperfect debugging phenomenon. In this study, a model aiming to incorporate fault introduction rate, fault removal efficiency and testing coverage into software reliability evaluation is developed, using testing coverage to express the fault detection rate and using fault removal efficiency to consider the fault repair. We compare the performance of the proposed model with several existing NHPP SRGMs using three sets of real failure data based on five criteria. The results exhibit that the model can give a better fitting and predictive performance.

  10. The Reliability of Results from National Tests, Public Examinations, and Vocational Qualifications in England

    Science.gov (United States)

    He, Qingping; Opposs, Dennis

    2012-01-01

    National tests, public examinations, and vocational qualifications in England are used for a variety of purposes, including the certification of individual learners in different subject areas and the accountability of individual professionals and institutions. However, there has been ongoing debate about the reliability and validity of their…

  11. The navicular position test - a reliable measure of the navicular bone position during rest and loading

    DEFF Research Database (Denmark)

    Spörndly-Nees, Søren; Dåsberg, Brian; Nielsen, Rasmus Oestergaard;

    2011-01-01

    Lower limb injuries are a large problem in athletes. However, there is a paucity of knowledge on the relationship between alignment of the medial longitudinal arch (MLA) of the foot and development of such injuries. A reliable and valid test to quantify foot type is needed to be able to investiga...

  12. Test-retest reliability of MRI-based disk position diagnosis of the temporomandibular joint.

    Science.gov (United States)

    Nagamatsu-Sakaguchi, Chiyomi; Maekawa, Kenji; Ono, Tsuyoshi; Yanagi, Yoshinobu; Minakuchi, Hajime; Miyawaki, Shouichi; Asaumi, Junichi; Takano-Yamamoto, Teruko; Clark, Glenn T; Kuboki, Takuo

    2012-02-01

    This study evaluated the test-retest reliability for determining the temporomandibular joint (TMJ) disk position, diagnosed using magnetic resonance imaging (MRI). These assessments were done as a base-line measurement for a prospective cohort study, which examines the risk factors for precipitation and progression of temporomandibular disorders. Fifteen subjects (mean age, 24.2 ± 0.94 years; male/female = 8/7) were recruited from the students of Okayama University Dental School. Sagittal MR TMJ images were taken with a 1.5-T MR scanner (Magneton Vision, Siemens) in close and maximal open positions twice at about 1-week (6-11 days) interval. The images were displayed using 200% magnification on a computer screen with a commercially available image software package (OSIRIS, UIN/HCUG). Three calibrated examiners diagnosed the disk positions using the standardized criteria. The disk position of each joint was classified as normal, anterior disk displacement with or without reduction, and others. The first and second disk position diagnoses were compared, and the test-retest reliability level was calculated using the kappa index. The second disk position diagnosis was consistent with the first in 27 out of 30 joints. The calculated kappa value representing the test-retest reliability level between the first and second disk position diagnosis was 0.812. These results indicated that the test-retest reliability of MRI-based diagnosis of TMJ disk positions at about 1-week interval was substantially high, even though they were not completely consistent.

  13. Reliability characteristics and applicability of a repeated sprint ability test in male young soccer players.

    Science.gov (United States)

    Castagna, Carlo; Francini, Lorenzo; Krustrup, Peter; Fenarnandes-da-Silva, Juliano; Póvoas, Susana C A; Bernardini, Andrea; D'Ottavio, Stefano

    2017-07-28

    The aim of this study was to examine the usefulness and reliability characteristics of a repeated sprint ability test considering 5 line sprints of 30-m interspersed with 30-s of active recovery in non-elite outfield young male soccer players. Twenty-six (age 14.9±1.2 years, height 1.72±0.12 cm, body mass 62.2±5.1 kg) players were tested 48 hours and 7 days apart for 5x30-m performance over 5 trials (T1-T5). Short- (T1-T2) and long-term reliability (T1-T3-T4-T5) were assessed with Intraclass Correlation Coefficient (ICC) and with typical error for measurement (TEM). Short- and long-term reliability ICCs and TEMs for total sprint time and best sprint performance were nearly perfect and satisfactory, respectively. Usefulness (as smallest worthwhile change and TEM ratio) resulted acceptable (i.e =1) and good (i.e >1) for total sprint time and best sprint performance, respectively. The present study revealed that the 5x30-m sprint test is a reliable field test in the short and long-term when the sum of sprint times and the best sprint performance are considered as outcome variables. Sprint performance decrements variables showed large variability across trials.

  14. Test-Retest Reliability of Self-Reported Sexual Health Measures among US Hispanic Adolescents

    Science.gov (United States)

    Jerman, Petra; Berglas, Nancy F.; Rohrbach, Louise A.; Constantine, Norman A.

    2016-01-01

    Objective: Although Hispanic adolescents in the USA are often the focus of sexual health interventions, their response to survey measures has rarely been assessed within evaluation studies. This study documents the test-retest reliability of a wide range of self-reported sexual health values, attitudes, knowledge and behaviours among Hispanic…

  15. Reliability and sensitivity to change of the timed standing balance test in children with down syndrome

    Directory of Open Access Journals (Sweden)

    Vencita Priyanka Aranha

    2016-01-01

    Full Text Available Objective: To estimate the reliability and sensitivity to change of the timed standing balance test in children with Down syndrome (DS. Methods: It was a nonblinded, comparison study with a convenience sample of subjects consisting of children with DS (n = 9 aged 8–17 years. The main outcome measure was standing balance which was assessed using timed standing balance test, the time required to maintain in four conditions, eyes open static, eyes closed static, eyes open dynamic, and eyes closed dynamic. Results: Relative reliability was excellent for all four conditions with an Interclass Correlation Coefficient (ICC ranging from 0.91 to 0.93. The variation between repeated measurements for each condition was minimal with standard error of measurement (SEM of 0.21–0.59 s, suggestive of excellent absolute reliability. The sensitivity to change as measured by smallest real change (SRC was 1.27 s for eyes open static, 1.63 s for eyes closed static, 0.58 s for eyes open dynamic, and 0.61 s for eyes closed static. Conclusions: Timed standing balance test is an easy to administer test and sensitive to change with strong absolute and relative reliabilities, an important first step in establishing its utility as a clinical balance measure in children with DS.

  16. Test-retest reliability of joint position and kinesthetic sense in the elbow of healthy subjects

    DEFF Research Database (Denmark)

    Juul-Kristensen, B.; Lund, Hans Aage; Hansen, K.;

    2008-01-01

    Proprioception is an important effect measure in neuromuscular function training in physiotherapy. Reliability studies of methods for measuring proprioception are few on joint position sense (JPS) and threshold to detection of a passive movement (TDPM) on the elbow. The aim was to study test...

  17. Reliability of biopsy-based diagnostic tests for Helicobacter pylori after treatment aimed at its eradication

    NARCIS (Netherlands)

    van der Wouden, ET; Thijs, JC; van Zwet, AA; Oey, HB; Kleibeuker, JH

    1999-01-01

    Objective Recurrence of Heliobacter pylori after apparently successful treatment mostly represents resurgence of the infection, rather than a new one. Therefore, the reliability of biopsy-based tests after treatment was investigated. Methods Four weeks or more after treatment, antral biopsy samples

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

    Science.gov (United States)

    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.

  19. The navicular position test - a reliable measure of the navicular bone position during rest and loading

    DEFF Research Database (Denmark)

    Spörndly-Nees, Søren; Dåsberg, Brian; Nielsen, Rasmus Oestergaard

    2011-01-01

    Lower limb injuries are a large problem in athletes. However, there is a paucity of knowledge on the relationship between alignment of the medial longitudinal arch (MLA) of the foot and development of such injuries. A reliable and valid test to quantify foot type is needed to be able to investigate...

  20. Temporal Stability of Strength-Based Assessments: Test-Retest Reliability of Student and Teacher Reports

    Science.gov (United States)

    Romer, Natalie; Merrell, Kenneth W.

    2013-01-01

    This study focused on evaluating the temporal stability of self-reported and teacher-reported perceptions of students' social and emotional skills and assets. We used a test-retest reliability procedure over repeated administrations of the child, adolescent, and teacher versions of the "Social-Emotional Assets and Resilience Scales".…

  1. Test-retest reliability of resting-state magnetoencephalography power in sensor and source space.

    Science.gov (United States)

    Martín-Buro, María Carmen; Garcés, Pilar; Maestú, Fernando

    2016-01-01

    Several studies have reported changes in spontaneous brain rhythms that could be used as clinical biomarkers or in the evaluation of neuropsychological and drug treatments in longitudinal studies using magnetoencephalography (MEG). There is an increasing necessity to use these measures in early diagnosis and pathology progression; however, there is a lack of studies addressing how reliable they are. Here, we provide the first test-retest reliability estimate of MEG power in resting-state at sensor and source space. In this study, we recorded 3 sessions of resting-state MEG activity from 24 healthy subjects with an interval of a week between each session. Power values were estimated at sensor and source space with beamforming for classical frequency bands: delta (2-4 Hz), theta (4-8 Hz), alpha (8-13 Hz), low beta (13-20 Hz), high beta (20-30 Hz), and gamma (30-45 Hz). Then, test-retest reliability was evaluated using the intraclass correlation coefficient (ICC). We also evaluated the relation between source power and the within-subject variability. In general, ICC of theta, alpha, and low beta power was fairly high (ICC > 0.6) while in delta and gamma power was lower. In source space, fronto-posterior alpha, frontal beta, and medial temporal theta showed the most reliable profiles. Signal-to-noise ratio could be partially responsible for reliability as low signal intensity resulted in high within-subject variability, but also the inherent nature of some brain rhythms in resting-state might be driving these reliability patterns. In conclusion, our results described the reliability of MEG power estimates in each frequency band, which could be considered in disease characterization or clinical trials.

  2. Test-retest reliability of the safe driving behavior measure for community-dwelling elderly drivers.

    Science.gov (United States)

    Song, Chiang-Soon; Lee, Joo-Hyun; Han, Sang-Woo

    2016-06-01

    [Purpose] The Safe Driving Behavior Measure (SDBM) is a self-report measurement tools that assesses the safe-driving behaviors of the elderly. The purpose of this study was to evaluate the test-retest reliability of the SDBM among community-dwelling elderly drivers. [Subjects and Methods] A total of sixty-one community-dwelling elderly were enrolled to investigate the reliability of the SDBM. The SDBM was assessed in two sessions that were conducted three days apart in a quiet and well-organized assessment room. That test-retest reliability of overall scores and three domain scores of the SDBM were statistically evaluated using intraclass correlation coefficients [ICC (2.1)]. Pearson correlation coefficients were used to quantify bivariate associations among the three domains of the SDBM. [Results] The SDBM demonstrated excellent rest-retest reliability for community-dwelling elderly drivers. The Cronbach alpha coefficients of the three domains of person-vehicle (0.979), person-environment (0.944), and person-vehicle-environment (0.971) of the SDBM indicate high internal consistency. [Conclusion] The results of this study suggest that the SDBM is a reliable measure for evaluating the safe- driving of automobiles by community-dwelling elderly, and is adequate for detecting changes in scores in clinical settings.

  3. Test-retest reliability of the 40 Hz EEG auditory steady-state response.

    Directory of Open Access Journals (Sweden)

    Kristina L McFadden

    Full Text Available Auditory evoked steady-state responses are increasingly being used as a marker of brain function and dysfunction in various neuropsychiatric disorders, but research investigating the test-retest reliability of this response is lacking. The purpose of this study was to assess the consistency of the auditory steady-state response (ASSR across sessions. Furthermore, the current study aimed to investigate how the reliability of the ASSR is impacted by stimulus parameters and analysis method employed. The consistency of this response across two sessions spaced approximately 1 week apart was measured in nineteen healthy adults using electroencephalography (EEG. The ASSR was entrained by both 40 Hz amplitude-modulated white noise and click train stimuli. Correlations between sessions were assessed with two separate analytical techniques: a channel-level analysis across the whole-head array and b signal-space projection from auditory dipoles. Overall, the ASSR was significantly correlated between sessions 1 and 2 (p<0.05, multiple comparison corrected, suggesting adequate test-retest reliability of this response. The current study also suggests that measures of inter-trial phase coherence may be more reliable between sessions than measures of evoked power. Results were similar between the two analysis methods, but reliability varied depending on the presented stimulus, with click train stimuli producing more consistent responses than white noise stimuli.

  4. Gearbox Reliability Collaborative Phase 1 and 2: Testing and Modeling Results; Preprint

    Energy Technology Data Exchange (ETDEWEB)

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

    2012-05-01

    The Gearbox Reliability Collaborative (GRC) investigates root causes of wind turbine gearbox premature failures and validates design assumptions that affect gearbox reliability using a combined testing and modeling approach. Knowledge gained from the testing and modeling of the GRC gearboxes builds an understanding of how the selected loads and events translate into internal responses of three-point mounted gearboxes. This paper presents some testing and modeling results of the GRC research during Phase 1 and 2. Non-torque loads from the rotor including shaft bending and thrust, traditionally assumed to be uncoupled with gearbox, affect gear and bearing loads and resulting gearbox responses. Bearing clearance increases bearing loads and causes cyclic loading, which could contribute to a reduced bearing life. Including flexibilities of key drivetrain subcomponents is important in order to reproduce the measured gearbox response during the tests using modeling approaches.

  5. Test-retest reliability of the Advanced Psychodiagnostic Interpretation (API) scoring system for the Bender Gestalt in chronic schizophrenics.

    Science.gov (United States)

    Aucone, E J; Wagner, E E; Raphael, A J; Golden, C J; Espe-Pfeifer, P; Dornheim, L; Seldon, J; Pospisil, T; Proctor-Weber, Z; Calabria, M

    2001-09-01

    This study assesses the test-retest reliability of the revised Advanced Psychodiagnostic Interpretation (API) scoring system for the Bender Gestalt Test (BGT). The API system identifies 207 possible distortions in a BGT protocol. Test-retest reliability for 40 schizophrenic patients tested twice with a mean interval of 6.4 years (SD=3.8 years) was good, ranging from .71 to .80. Further reliability and validity studies are needed to further demonstrate the effectiveness of the system.

  6. Implication of Atmospheric Wetness Levels on Corrosion at a Coating Defect during Accelerated Testing

    Science.gov (United States)

    2012-08-28

    Outline • Objectives • Atmospheric corrosion • Testing Approach • Effect of RH on corrosion of steel • Effect of inhibitor addition on coated steel... inhibitor migration in the coating . For a given test method, wet and dry times will influence inhibitor mobility, and thus corrosion rate Continuous...Implication of Atmospheric Wetness Levels on Corrosion at a Coating Defect during Accelerated Testing James F. Dante Southwest Research Institute

  7. Development of a photovoltaic module qualification test based on combined-environment accelerated stress data

    Science.gov (United States)

    Trenchard, S. E.; Royal, E.; Anderson, R. T.

    1982-01-01

    The U.S. Coast Guard has developed a qualification test to screen photovoltaic modules for utilization on marine aids to navigation. The test is based on a combined-environment of hot and cold saltwater immersion and air pressurization. The test has demonstrated a very high acceleration factor and excellent correlation of electrical failures with modules in a concurrent real-time marine exposure.

  8. Students' Initial Knowledge State and Test Design: Towards a Valid and Reliable Test Instrument

    Science.gov (United States)

    CoPo, Antonio Roland I.

    2015-01-01

    Designing a good test instrument involves specifications, test construction, validation, try-out, analysis and revision. The initial knowledge state of forty (40) tertiary students enrolled in Business Statistics course was determined and the same test instrument undergoes validation. The designed test instrument did not only reveal the baseline…

  9. Reliability of utricular function testing sinusoidal translation profile during unilateral centrifugation.

    Science.gov (United States)

    Buytaert, K I; Vanspauwen, R; Van de Heyning, P H; Wuyts, F L

    2010-01-01

    The unilateral centrifugation test is one of the few vestibular tests that evaluate the utricles side by side. During this test, a subject is rotated about an earth vertical axis at high rotation speeds (e.g. 400 degrees/s) and translated sideways along the interaural axis to align the axis of rotation consecutively with the right and the left utricle. The combined rotation and translation induces ocular counter rolling (OCR), which is measured using three-dimensional video-oculography. Recently, a new model has been proposed to analyse the OCR. The model is based on contributions from both the semicircular canals and the utricles. Concomitant with the new model a new stimulation profile using a sinusoidal translation profile during the unilateral centrifugation has been introduced [1]. The current study presents the test-retest reliability as well as the robustness of the new stimulation method, based on data of 67 healthy subjects. Test-retest reliability was based on repeated measurements of a group of subjects. To test the robustness of the new sinusoidal translation paradigm, we investigated the effect of a different amplitude of the sinusoidal translation (6 cm instead of 4 cm) and of an offset in translation (from -3 to +5 cm, instead of from -4 to +4 cm) on the parameters. Several statistical measures were used to reflect the reliability: intraclass correlation coefficient (ICC), the "coefficient of variation of the method error" and the "minimal difference" (MD). All relevant variables from the physiological model for the OCR induced by unilateral centrifugation show a good to excellent reliability during the test-retest study and the relevant parameters remain unaffected by the changes applied to the translation profile (p > 0.05) as predicted by the model. Additionally, all observed differences are smaller than the MD values calculated in the test-retest part of the study.

  10. INFLUENCE BILIARY DYSKINESIA ON RELIABLE CHAIR-TEST IN PATIENTS WITH CHRONIC NON-ATROPHIC GASTRITIS

    OpenAIRE

    Avramenko, A. A.; Korolenko, R N; Shuhtina, I. N.

    2017-01-01

    It was carried out a comprehensive survey of 45 patients with chronic non-atrophic gastritis with biliary dyskinesia, which included ultrasound diagnosis of abdominal organs, pH meters, esophagogastroduodenoscopy, double testing for H. pylori infection and histological examination of the gastric mucosa to 4 - m topographic zones, stool test and determine the level of antibodies to HP infection by ELISA. It was found that the presence of biliary dyskinesia reduces the reliability of the chair-...

  11. THE RELIABILITY AND VALIDITY OF THE NEW HARRIS-GOODENOUGH DRAW-A-MAN TEST.

    Science.gov (United States)

    DUNN, JAMES A.

    A SERIES OF STUDIES SOUGHT TO ASCERTAIN (1) INTER- AND INTRA-RATER RELIABILITY FOR THE HARRIS-GOODENOUGH DRAW-A-MAN TEST, (2) DRAW-A-MAN (DAM) VALIDITY, AND DRAW-A-WOMAN (DAW) VALIDITY. THE DRAWINGS OF 72 STUDENTS IN AN UPPER MIDDLE CLASS WERE SCORED INDEPENDENTLY BY TWO SELF-TAUGHT SCORERS, ONE OF WHOM ALSO RESCORED THE TEST A WEEK LATER. THE…

  12. Interrater and Test-Retest Reliability of the Beery Visual-Motor Integration in Schoolchildren.

    Science.gov (United States)

    Harvey, Erin M; Leonard-Green, Tina K; Mohan, Kathleen M; Kulp, Marjean Taylor; Davis, Amy L; Miller, Joseph M; Twelker, J Daniel; Campus, Irene; Dennis, Leslie K

    2017-05-01

    To assess interrater and test-retest reliability of the 6th Edition Beery-Buktenica Developmental Test of Visual-Motor Integration (VMI) and test-retest reliability of the VMI Visual Perception Supplemental Test (VMIp) in school-age children. Subjects were 163 Native American third- to eighth-grade students with no significant refractive error (astigmatism VMI and VMIp were administered twice, on separate days. All VMI tests were scored by two trained scorers, and a subset of 50 tests was also scored by an experienced scorer. Scorers strictly applied objective scoring criteria. Analyses included interrater and test-retest assessments of bias, 95% limits of agreement, and intraclass correlation analysis. Trained scorers had no significant scoring bias compared with the experienced scorer. One of the two trained scorers tended to provide higher scores than the other (mean difference in standardized scores = 1.54). Interrater correlations were strong (0.75 to 0.88). VMI and VMIp test-retest comparisons indicated no significant bias (subjects did not tend to score better on retest). Test-retest correlations were moderate (0.54 to 0.58). The 95% limits of agreement for the VMI were -24.14 to 24.67 (scorer 1) and -26.06 to 26.58 (scorer 2), and the 95% limits of agreement for the VMIp were -27.11 to 27.34. The 95% limit of agreement for test-retest differences will be useful for determining if the VMI and VMIp have sufficient sensitivity for detecting change with treatment in both clinical and research settings. Further research on test-retest reliability reporting 95% limits of agreement for children across different age ranges is recommended, particularly if the test is to be used to detect changes due to intervention or treatment.

  13. Test-retest reliability of patient reports of low back pain.

    Science.gov (United States)

    Roach, K E; Brown, M D; Dunigan, K M; Kusek, C L; Walas, M

    1997-11-01

    Low back pain is, in large part, a subjective illness. Clinicians must use patient descriptions of the severity and location of low back pain and how it responds to various activities and positions to make diagnostic and treatment decisions. Therefore, it is important to understand how reliably patients describe these aspects of low back pain. The purpose of this study was to determine the test-retest reliability of a visual analogue scale measure of pain intensity, a pain drawing measure of pain location, and the pain response to activity and position questionnaire. Fifty-three subjects (28 men and 25 women) with a mean age of 54.2 years were recruited from an outpatient orthopaedic clinic. They completed the visual analogue scale, pain drawing, and pain response to activity and position questionnaire before and again immediately after seeing their physician. Thirty-three subjects also completed the visual analogue scale and pain drawing measure that evening and the next morning. Test-retest reliability of the visual analogue scale and pain drawing measure was examined using an intraclass correlation coefficient. Reliability of each item on the pain response to activity and position questionnaire was examined by calculating an unweighted Cohen's kappa. Overall, the three pain measures demonstrated fair to good test-retest reliability: 1) visual analogue scale = .66-.93, 2) pain drawing = .58-.94, and 3) pain response to activity and position questionnaire = .46-.89. The results of this study suggest that, although there is some variability in how consistently patients report various aspects of low back pain, the reliability of these pain measures is sufficient to permit their use in making clinical decisions and measuring treatment outcomes.

  14. Meeting Human Reliability Requirements through Human Factors Design, Testing, and Modeling

    Energy Technology Data Exchange (ETDEWEB)

    R. L. Boring

    2007-06-01

    In the design of novel systems, it is important for the human factors engineer to work in parallel with the human reliability analyst to arrive at the safest achievable design that meets design team safety goals and certification or regulatory requirements. This paper introduces the System Development Safety Triptych, a checklist of considerations for the interplay of human factors and human reliability through design, testing, and modeling in product development. This paper also explores three phases of safe system development, corresponding to the conception, design, and implementation of a system.

  15. Test-particle acceleration in a hierarchical three-dimensional turbulence model

    Energy Technology Data Exchange (ETDEWEB)

    Dalena, S.; Rappazzo, A. F.; Matthaeus, W. H. [Bartol Research Institute, Department of Physics and Astronomy, University of Delaware, DE 19716 (United States); Dmitruk, P. [Departamento de Fisica, Facultad de Ciencias Exactas y Naturales, Universidad de Buenos Aires, Ciudad Universitaria, 1428 Buenos Aires (Argentina); Greco, A., E-mail: serena.dalena@fis.unical.it [Dipartimento di Fisica, Università della Calabria, I-87036 Cosenza (Italy)

    2014-03-10

    The acceleration of charged particles is relevant to the solar corona over a broad range of scales and energies. High-energy particles are usually detected in concomitance with large energy release events like solar eruptions and flares. Nevertheless, acceleration can occur at smaller scales, characterized by dynamical activity near current sheets. To gain insight into the complex scenario of coronal charged particle acceleration, we investigate the properties of acceleration with a test-particle approach using three-dimensional magnetohydrodynamic (MHD) models. These are obtained from direct solutions of the reduced MHD equations, well suited for a plasma embedded in a strong axial magnetic field, relevant to the inner heliosphere. A multi-box, multiscale technique is used to solve the equations of motion for protons. This method allows us to resolve an extended range of scales present in the system, namely, from the ion inertial scale of the order of a meter up to macroscopic scales of the order of 10 km (1/100th of the outer scale of the system). This new technique is useful to identify the mechanisms that, acting at different scales, are responsible for acceleration to high energies of a small fraction of the particles in the coronal plasma. We report results that describe acceleration at different stages over a broad range of time, length, and energy scales.

  16. The conversion of CESR to operate as the Test Accelerator, CesrTA. Part 1: overview

    Science.gov (United States)

    Billing, M. G.

    2015-07-01

    Cornell's electron/positron storage ring (CESR) was modified over a series of accelerator shutdowns beginning in May 2008, which substantially improves its capability for research and development for particle accelerators. CESR's energy span from 1.8 to 5.6 GeV with both electrons and positrons makes it ideal for the study of a wide spectrum of accelerator physics issues and instrumentation related to present light sources and future lepton damping rings. Additionally a number of these are also relevant for the beam physics of proton accelerators. This paper outlines the motivation, design and conversion of CESR to a test accelerator, CESRTA, enhanced to study such subjects as low emittance tuning methods, electron cloud (EC) effects, intra-beam scattering, fast ion instabilities as well as general improvements to beam instrumentation. While the initial studies of CESRTA focussed on questions related to the International Linear Collider (ILC) damping ring design, CESRTA is a very flexible storage ring, capable of studying a wide range of accelerator physics and instrumentation questions. This paper contains the outline and the basis for a set of papers documenting the reconfiguration of the storage ring and the associated instrumentation required for the studies described above. Further details may be found in these papers.

  17. Proposal of the Next Incarnation of Accelerator Test Facility at KEK for the International Linear Collider

    CERN Document Server

    Hayano, Hitoshi; Angal-Kalinin, Deepa; Appleby, Robert; Araki, Sakae; Bambade, Philip; Bane, Karl Leopold Freitag; Blair, Grahame A; Boogert, Stewart Takashi; Boorman, Gary; Brachmann, Axel; Braun, Hans Heinrich; Burrows, P N; Carter, John; Choi Jae Young; Christian, Glenn B; Danagulyan, S; Delerue, Nicolas; Driouichi, Chafik; Gao, Jie; Grishanov, Boris I; Gronberg, Jeff; Higashi, Yasuo; Himel, Thomas; Honda, Yosuke; Howell, David Francis; Iwashita, Yoshihisa; Jones, James; Kalinin, Alexander; Kanazawa, Ken Ichi; Kang Heung Sik; Kim Eun San; Kim Sang Hee; Kubo, Kiyoshi; Kumada, Masayuki; Kume, T; Kuriki, Masao; Kuroda, Shigeru; Lyapin, A; Liu Wan Ming; Logatchev, P V; Malton, Stephen; Markiewicz, Thomas W; Masuzawa, Mika; Mihara, Takanori; Molloy, Stephen; Mtingwa, S; Naito, Takashi; Napoly, Olivier; Nelson, Janice; Okugi, Toshiyuki; Payet, Jacques; Pei Guo Xi; Phinney, Nan; Pivi, M T F; Podgorny, Fedor; Price, Michael T; Raubenheimer, Tor O; Reichold, Armin; Ross, Marc; Ruland, Robert; Sanuki, Tomoyuki; Schulte, Daniel; Seryi, Andrei; Soo Ko In; Spencer, Cherrill M; Suehara, Taikan; Sugahara, Ryuhei; Takahashi, Takeshi; Tauchi, Toshiaki; Telnov, Valery I; Tenenbaum, P G; Terunuma, Nobuhiro; Toge, Nobu; Torrence, Eric; Urakawa, Junji; Urner, David; Vogel, Vladimir; Walker, Nicholas J; Wang Jiu Qing; White, Glen; Woodley, Mark; Yamaoka, Hiroshi; Yokoya, Kaoru; Yun Huang Jung; Zimmermann, Frank

    2005-01-01

    The realization of the International Linear Collider (ILC) will require the ability to create and reliably maintain nanometer size beams. The ATF damping ring is the unique facility where ILC emittancies are possible. In this paper we present and evaluate the proposal to create a final focus facility at the ATF which, using compact final focus optics and an ILC-like bunch train, would be capable of achieving 35nm beam size. Such a facility would enable the development of beam diagnostics and tuning methods, as well as the training of young accelerator physicists.

  18. Proposal of the Next Incarnation of Accelerator Test Facility at KEK for the International Linear Collider

    Energy Technology Data Exchange (ETDEWEB)

    Araki, S.; Hayano, H.; Higashi, Y.; Honda, Y.; Kanazawa, K.; Kubo, K.; Kume, T.; Kuriki, M.; Kuroda, S.; Masuzawa, M.; Naito, T.; Okugi, T.; Sugahara, R.; Takahashi, T.; Tauchi, T.; Terunuma, N.; Toge, N.; Urakawa, J.; Vogel, V.; Yamaoka, H.; Yokoya, K.; /KEK, Tsukuba /Beijing, Inst. High Energy Phys. /Novosibirsk, IYF /Daresbury /CERN /Hiroshima

    2005-05-27

    To reach design luminosity, the International Linear Collider (ILC) must be able to create and reliably maintain nanometer size beams. The ATF damping ring is the unique facility where ILC emittances are possible. In this paper we present and evaluate the proposal to create a final focus facility at the ATF which, using compact final focus optics and an ILC-like bunch train, would be capable of achieving 37 nm beam size. Such a facility would enable the development of beam diagnostics and tuning methods, as well as the training of young accelerator physicists.

  19. Reliability and Validity of Culturally Adapted Executive Function Performance Test for Koreans with Stroke.

    Science.gov (United States)

    Kim, Hee; Lee, Yu-Na; Jo, Eun-Mi; Lee, Eun-Young

    2017-05-01

    Executive Function Performance Test was unusable in Asia because of cultural differences, although evaluating the effect that executive function has on real life is essential to people with stroke. The aims of this study were to report the development and standardization of culturally appropriate Executive Function Performance Test for Koreans (EFPT-K) and to verify its reliability and validity in the stroke population. EFPT-K was developed by going through the process of translation, back-translation, and an expert committee's conference on cultural adaptation. Inter-rater reliability was examined and 34 people with stroke were recruited to test the internal consistency and criterion validity of EFPT-K. To verify the criterion validity, EFPT-K scores were compared with those of the Trail-Making Test, the Korean Color-Word Stroop Test, the Digit Span Test, and the Assessment of Motor and Process Skills (AMPS). Inter-rater reliability and internal consistency of the total score of EFPT-K supported high levels of reliability. In the criterion validity of EFPT-K, all neuropsychological tests but digits backward showed a correlation with the total score of EFPT-K, and AMPS components of initiation, notice/response, and termination showed a moderate correlation with the EFPT-K score. EFPT-K is a useful tool to evaluate the executive functioning of patients with stroke in real-life tasks and could be used as a sample in other Asian cultures where thorough evaluation of executive function in the performance of daily life is needed. Copyright © 2017 National Stroke Association. Published by Elsevier Inc. All rights reserved.

  20. Development of Neural Network Model for Predicting Peak Ground Acceleration Based on Microtremor Measurement and Soil Boring Test Data

    Directory of Open Access Journals (Sweden)

    T. Kerh

    2012-01-01

    Full Text Available It may not be possible to collect adequate records of strong ground motions in a short period of time; hence microtremor survey is frequently conducted to reveal the stratum structure and earthquake characteristics at a specified construction site. This paper is therefore aimed at developing a neural network model, based on available microtremor measurement and on-site soil boring test data, for predicting peak ground acceleration at a site, in a science park of Taiwan. The four key parameters used as inputs for the model are soil values of the standard penetration test, the medium grain size, the safety factor against liquefaction, and the distance between soil depth and measuring station. The results show that a neural network model with four neurons in the hidden layer can achieve better performance than other models presently available. Also, a weight-based neural network model is developed to provide reliable prediction of peak ground acceleration at an unmeasured site based on data at three nearby measuring stations. The method employed in this paper provides a new way to treat this type of seismic-related problem, and it may be applicable to other areas of interest around the world.

  1. Development, test-retest reliability and validity of the Pharmacy Value-Added Services Questionnaire (PVASQ).

    Science.gov (United States)

    Tan, Christine L; Hassali, Mohamed A; Saleem, Fahad; Shafie, Asrul A; Aljadhey, Hisham; Gan, Vincent B

    2015-01-01

    (i) To develop the Pharmacy Value-Added Services Questionnaire (PVASQ) using emerging themes generated from interviews. (ii) To establish reliability and validity of questionnaire instrument. Using an extended Theory of Planned Behavior as the theoretical model, face-to-face interviews generated salient beliefs of pharmacy value-added services. The PVASQ was constructed initially in English incorporating important themes and later translated into the Malay language with forward and backward translation. Intention (INT) to adopt pharmacy value-added services is predicted by attitudes (ATT), subjective norms (SN), perceived behavioral control (PBC), knowledge and expectations. Using a 7-point Likert-type scale and a dichotomous scale, test-retest reliability (N=25) was assessed by administrating the questionnaire instrument twice at an interval of one week apart. Internal consistency was measured by Cronbach's alpha and construct validity between two administrations was assessed using the kappa statistic and the intraclass correlation coefficient (ICC). Confirmatory Factor Analysis, CFA (N=410) was conducted to assess construct validity of the PVASQ. The kappa coefficients indicate a moderate to almost perfect strength of agreement between test and retest. The ICC for all scales tested for intra-rater (test-retest) reliability was good. The overall Cronbach' s alpha (N=25) is 0.912 and 0.908 for the two time points. The result of CFA (N=410) showed most items loaded strongly and correctly into corresponding factors. Only one item was eliminated. This study is the first to develop and establish the reliability and validity of the Pharmacy Value-Added Services Questionnaire instrument using the Theory of Planned Behavior as the theoretical model. The translated Malay language version of PVASQ is reliable and valid to predict Malaysian patients' intention to adopt pharmacy value-added services to collect partial medicine supply.

  2. Development, test-retest reliability and validity of the Pharmacy Value-Added Services Questionnaire (PVASQ

    Directory of Open Access Journals (Sweden)

    Tan CL

    2015-09-01

    Full Text Available Objective: (i To develop the Pharmacy Value-Added Services Questionnaire (PVASQ using emerging themes generated from interviews. (ii To establish reliability and validity of questionnaire instrument. Methods: Using an extended Theory of Planned Behavior as the theoretical model, face-to-face interviews generated salient beliefs of pharmacy value-added services. The PVASQ was constructed initially in English incorporating important themes and later translated into the Malay language with forward and backward translation. Intention (INT to adopt pharmacy value-added services is predicted by attitudes (ATT, subjective norms (SN, perceived behavioral control (PBC, knowledge and expectations. Using a 7-point Likert-type scale and a dichotomous scale, test-retest reliability (N=25 was assessed by administrating the questionnaire instrument twice at an interval of one week apart. Internal consistency was measured by Cronbach’s alpha and construct validity between two administrations was assessed using the kappa statistic and the intraclass correlation coefficient (ICC. Confirmatory Factor Analysis, CFA (N=410 was conducted to assess construct validity of the PVASQ. Results: The kappa coefficients indicate a moderate to almost perfect strength of agreement between test and retest. The ICC for all scales tested for intra-rater (test-retest reliability was good. The overall Cronbach’ s alpha (N=25 is 0.912 and 0.908 for the two time points. The result of CFA (N=410 showed most items loaded strongly and correctly into corresponding factors. Only one item was eliminated. Conclusions: This study is the first to develop and establish the reliability and validity of the Pharmacy Value-Added Services Questionnaire instrument using the Theory of Planned Behavior as the theoretical model. The translated Malay language version of PVASQ is reliable and valid to predict Malaysian patients’ intention to adopt pharmacy value-added services to collect partial

  3. Evidence of Reliability and Validity for a Children’s Auditory Continuous Performance Test

    Directory of Open Access Journals (Sweden)

    Michael J. Lasee

    2013-11-01

    Full Text Available Continuous Performance Tests (CPTs are commonly utilized clinical measures of attention and response inhibition. While there have been many studies of CPTs that utilize a visual format, there is considerably less research employing auditory CPTs. The current study provides initial reliability and validity evidence for the Auditory Vigilance Screening Measure (AVSM, a newly developed CPT. Participants included 105 five- to nine-year-old children selected from two rural Midwestern school districts. Reliability data for the AVSM was collected through retesting of 42 participants. Validity was evaluated through correlation of AVSM scales with subscales from the ADHD Rating Scale–IV. Test–retest reliability coefficients ranged from .62 to .74 for AVSM subscales. A significant (r = .31 correlation was obtained between the AVSM Impulsivity Scale and teacher ratings of inattention. Limitations and implications for future study are discussed.

  4. Evidences of validity and reliability of the Luria-Nebraska Test for Children

    Directory of Open Access Journals (Sweden)

    Ricardo Franco de Lima

    2016-01-01

    Full Text Available Abstract This paper aimed to verify evidences of validity and reliability of Luria-Nebraska Test for Children (TLN-C, in Portuguese. Three hundred eighty-seven students aged 6–13 years old, with learning difficulties, comprised the study. They were assessed with the Wechsler Intelligence Scale for Children (WISC-III and TLN-C; and effect of age differences, as well as accuracy rating by internal consistency were investigated. Age effects were found for all subtests and in the general score, except for receptive speech subtest, even when total IQ effect was controlled. Reliability analysis had satisfactory results (0.79. The TLN-C showed evidences of validity and reliability. Receptive speech subtest requires revision.

  5. Test-retest reliability of a continuous glucose monitoring system in individuals with type 2 diabetes.

    Science.gov (United States)

    Terada, Tasuku; Loehr, Sarah; Guigard, Emmanuel; McCargar, Linda J; Bell, Gordon J; Senior, Peter; Boulé, Normand G

    2014-08-01

    This study determined the test-retest reliability of a continuous glucose monitoring system (CGMS) (iPro™2; Medtronic, Northridge, CA) under standardized conditions in individuals with type 2 diabetes (T2D). Fourteen individuals with T2D spent two nonconsecutive days in a calorimetry unit. On both days, meals, medication, and exercise were standardized. Glucose concentrations were measured continuously by CGMS, from which daily mean glucose concentration (GLU(mean)), time spent in hyperglycemia (t(>10.0 mmol/L)), and meal, exercise, and nocturnal mean glucose concentrations, as well as glycemic variability (SD(w), percentage coefficient of variation [%cv(w)], mean amplitude of glycemic excursions [MAGEc, MAGE(ave), and MAGE(abs.gos)], and continuous overlapping net glycemic action [CONGA(n)]) were estimated. Absolute and relative reliabilities were investigated using coefficient of variation (CV) and intraclass correlation, respectively. Relative reliability ranged from 0.77 to 0.95 (Pmeal, exercise, and nocturnal glycemia with CV ranging from 3.9% to 11.7%. Despite significant relative reliability (R=0.93; P10.0 mmol/L) showed larger CV (54.7%). Among the different glycemic variability measures, a significant between-day difference was observed in MAGEc, MAGE(ave), CONGA6, and CONGA12. The remaining measures (i.e., SD(w), %cv(w), MAGE(abs.gos), and CONGA1-4) indicated no between-day differences and significant relative reliability. In individuals with T2D, CGMS-estimated glycemic profiles were characterized by high relative and absolute reliability for both daily and shorter-term measurements as represented by GLUmean and meal, exercise, and nocturnal glycemia. Among the different methods to calculate glycemic variability, our results showed SD(w), %cv(w), MAGE(abs.gos), and CONGAn with n ≤ 4 were reliable measures. These results suggest the usefulness of CGMS in clinical trials utilizing repeated measured.

  6. Test-retest reliability of the Bod Pod: the effect of multiple assessments.

    Science.gov (United States)

    Tucker, Larry A; Lecheminant, James D; Bailey, Bruce W

    2014-04-01

    The Bod Pod uses air-displacement plethysmography to estimate body fat percentage (BF%). This study was designed to assess the test-retest reliability of the Bod Pod. The study included 283 women (M age = 41.0 yr., SD = 3.0). Each participant was tested at least twice in the Bod Pod. Results showed no significant mean difference between the test and the retest. The intraclass correlation coefficient (ICC) was .991. However, the absolute value of the initial trial differences (absolute mean difference) was .96 (SD = .90). A third assessment of BF% was taken when the initial trial difference was greater than 1 percentage point, and the two closest values were compared. This strategy resulted in a significant decrease in the absolute mean difference, from .96 to .55 percentage point, and ICC increased to .998. The Bod Pod appears to measure body fat percentage reliably; however, findings suggest that multiple trials may be necessary to detect small treatment effects.

  7. Test-retest reliability of lifting and carrying in a 2-day functional capacity evaluation.

    Science.gov (United States)

    Reneman, M F; Dijkstra, P U; Westmaas, M; Göeken, L N H

    2002-12-01

    The objectives of this study were to establish test-retest reliability of lifting and carrying of a functional capacity evaluation (FCE) on two consecutive days and to verify the need for a 2-day protocol. A cohort of 50 patients (39 men, 11 women) with nonspecific low back pain were evaluated using a 2-day FCE protocol. Intraclass correlation coefficients (ICC) were calculated for weight lifted and carried. Predictive relationships between test and retest were explored by means of a regression analysis. The results of ICC were lifting low 0.87, lifting overhead 0.87, and carrying 0.77. Performances on day 2 were on an average 6-9% higher. Other than the amount of weight handled on day 1, no variable was found to predict performance on day 2. It was concluded that test-retest reliability of lifting and carrying was good, and the need for a 2-day protocol could not be confirmed.

  8. Accuracy and reliability of Tzanck test compared to histopathology for diagnosis of basal cell carcinoma

    Directory of Open Access Journals (Sweden)

    Vivek Kumar Dey

    2015-01-01

    Full Text Available Background: Histopathology is considered the gold standard for diagnosis of basal cell carcinoma (BCC but is time consuming and needs expertise to make a correct diagnosis. On the other hand, Tzanck test is a simple, easy, inexpensive and rapid test which uses exfoliative cytology to make a diagnosis. Objective: To compare the results of Tzanck test with histopathology in the diagnosis of BCC and to evaluate the diagnostic reliability and accuracy of Tzanck test in BCC. Materials and Method: Twenty-six patients with clinical suspicion of BCC were recruited. Samples for Tzanck test and histopathology were taken and diagnoses made independently. Results of Tzanck test were compared with histopathology. Results: Twenty-three cases were histopathologically proved to be BCC. Tzanck test correlated in 12 cases of BCC and could exclude all three non-BCC lesions. In 11 cases it failed to diagnose BCC. The sensitivity and specificity of Tzanck test were 52.2% and 100%, respectively, and positive and negative predictive values were 100% and 21.4%. Conclusion: Tzanck test can be recommended for initial, rapid evaluation of a clinically diagnosed case of BCC. Under experienced hands, it reliably confirms BCC. The limitation is low negative predictive value. Since it does not give information about subtypes of BCC which is of great value in therapeutic planning, histopathological confirmation is mandatory.

  9. The navicular position test - a reliable measure of the navicular bone position during rest and loading

    DEFF Research Database (Denmark)

    Spörndly-Nees, Søren; Dåsberg, Brian; Nielsen, Rasmus Oestergaard

    2011-01-01

    Background: Lower limb injuries are a large problem in athletes. However, there is a paucity of knowledge on the relationship between alignment of the medial longitudinal arch (MLA) of the foot and development of such injuries. A reliable and valid test to quantify foot type is needed to be able ....... When cut off values to categorize the MLA into planus, rectus, or cavus feet, has been determined and presented, the test could be used in prospective observational studies investigating the role of the arch type on the development of various lower limb injuries.......Background: Lower limb injuries are a large problem in athletes. However, there is a paucity of knowledge on the relationship between alignment of the medial longitudinal arch (MLA) of the foot and development of such injuries. A reliable and valid test to quantify foot type is needed to be able...... to investigate the relationship between arch type and injury likelihood. Feiss Line is a valid clinical measure of the MLA. However, no study has investigated the reliability of the test. Objectives: The purpose was to describe a modified version of the Feiss Line test and to determine the intra- and inter...

  10. Reliability and validity of the NeuroCognitive Performance Test, a web-based neuropsychological assessment.

    Science.gov (United States)

    Morrison, Glenn E; Simone, Christa M; Ng, Nicole F; Hardy, Joseph L

    2015-01-01

    The NeuroCognitive Performance Test (NCPT) is a brief, repeatable, web-based cognitive assessment platform that measures performance across several cognitive domains. The NCPT platform is modular and includes 18 subtests that can be arranged into customized batteries. Here we present normative data from a sample of 130,140 healthy volunteers for an NCPT battery consisting of 8 subtests. Participants took the NCPT remotely and without supervision. Factor structure and effects of age, education, and gender were evaluated with this normative dataset. Test-retest reliability was evaluated in a subset of participants who took the battery again an average of 78.8 days later. The eight NCPT subtests group into 4 putative cognitive domains, have adequate to good test-retest reliability, and are sensitive to expected age- and education-related cognitive effects. Concurrent validity to standard neuropsychological tests was demonstrated in 73 healthy volunteers. In an exploratory analysis the NCPT battery could differentiate those who self-reported Mild Cognitive Impairment or Alzheimer's disease from matched healthy controls. Overall these results demonstrate the reliability and validity of the NCPT battery as a measure of cognitive performance and support the feasibility of web-based, unsupervised testing, with potential utility in clinical and research settings.

  11. Test-retest reliability of the Clinical Learning Environment, Supervision and Nurse Teacher (CLES + T) scale.

    Science.gov (United States)

    Gustafsson, Margareta; Blomberg, Karin; Holmefur, Marie

    2015-07-01

    The Clinical Learning Environment, Supervision and Nurse Teacher (CLES + T) scale evaluates the student nurses' perception of the learning environment and supervision within the clinical placement. It has never been tested in a replication study. The aim of the present study was to evaluate the test-retest reliability of the CLES + T scale. The CLES + T scale was administered twice to a group of 42 student nurses, with a one-week interval. Test-retest reliability was determined by calculations of Intraclass Correlation Coefficients (ICCs) and weighted Kappa coefficients. Standard Error of Measurements (SEM) and Smallest Detectable Difference (SDD) determined the precision of individual scores. Bland-Altman plots were created for analyses of systematic differences between the test occasions. The results of the study showed that the stability over time was good to excellent (ICC 0.88-0.96) in the sub-dimensions "Supervisory relationship", "Pedagogical atmosphere on the ward" and "Role of the nurse teacher". Measurements of "Premises of nursing on the ward" and "Leadership style of the manager" had lower but still acceptable stability (ICC 0.70-0.75). No systematic differences occurred between the test occasions. This study supports the usefulness of the CLES + T scale as a reliable measure of the student nurses' perception of the learning environment within the clinical placement at a hospital.

  12. Effect of precipitation pattern on leaching of preservative from treated wood and implications for accelerated testing

    Science.gov (United States)

    Stan Lebow

    2014-01-01

    There is a need to develop improved accelerated test methods for evaluating the leaching of wood preservatives from treated wood exposed to precipitation. In this study the effects of rate of rainfall and length of intervals between rainfall events on leaching was evaluated by exposing specimens to varying patterns of simulated rainfall under controlled laboratory...

  13. Compilation of radiation damage test data part III: materials used around high-energy accelerators

    CERN Document Server

    Beynel, P; Schönbacher, H; CERN. Geneva

    1982-01-01

    For pt.II see CERN report 79-08 (1979). This handbook gives the results of radiation damage tests on various engineering materials and components intended for installation in radiation areas of the CERN high-energy particle accelerators. It complements two previous volumes covering organic cable-insulating materials and thermoplastic and thermosetting resins.

  14. Three decades of development and achievements: the heavy vehicle simulator in accelerated pavement testing

    CSIR Research Space (South Africa)

    Du Plessis, L

    2006-06-01

    Full Text Available The purpose of this paper is two fold. First, it will provide a brief description of the technological developments involved in the Heavy Vehicle Simulator (HVS) accelerated pavement testing equipment. This covers the period from concept in the late...

  15. Matching marine corrosion: new accelerated test gives good correlation with outdoor exposure

    NARCIS (Netherlands)

    Hoeflaak, M.

    2004-01-01

    An extensive study of the corrosion resistance of a large number and a large variety of coatings systems for steel protection has been carried out. With these, three types of accelerated tests have been correlated with observerations from two years of outdoor exposure in a marine environment, and a

  16. Reliability of a new supination resistance measurement device and validation of the manual supination resistance test.

    Science.gov (United States)

    Griffiths, Ian B; McEwan, Islay M

    2012-01-01

    Kinematic observations are inconsistent in predicting lower-extremity injury risk, and research suggests that kinetic variables may be more important in this regard. Before kinetics can be prospectively investigated, we need reliable ways of measuring them clinically. A measurement instrument was manufactured that closely mirrors a manual test used to clinically estimate supination resistance force. The reliability of the instrument and the validity of the clinical test were investigated. The left feet of 26 healthy individuals (17 men and 9 women; mean ± SD age, 25.9 ± 9.2 years; mean ± SD weight, 77.7 ± 13.3 kg) were assessed. Foot Posture Index (FPI-6), manual supination resistance, and machine supination resistance were measured. Intrarater and interrater reliability of all of the measurements were calculated. Correlations of the supination resistance measured by the device with FPI-6, the manual supination resistance test, and body weight were investigated. Interrater reliability of all of the measurements was generally poor. The supination resistance machine correlated highly with the manual supination test for the rater experienced with its use. Supination resistance measurements correlated poorly with the FPI-6 and weakly with body weight. The supination resistance machine was shown to have sufficient limits of agreement for the study, but improvements need to be made for more meaningful research going forward. In this study, the force required to supinate a foot was independent of its posture, and approximately 12% of it was explained by body weight. Further work is required with a much larger sample size to build regression models that sufficiently predict supination resistance force and that will be of clinical use. The manual supination test is a valid clinical test for clinicians experienced in its use.

  17. Reliability of clinical tests to evaluate nerve function and mechanosensitivity of the upper limb peripheral nervous system

    Directory of Open Access Journals (Sweden)

    Bachmann Lucas M

    2009-01-01

    Full Text Available Abstract Background Clinical tests to assess peripheral nerve disorders can be classified into two categories: tests for afferent/efferent nerve function such as nerve conduction (bedside neurological examination and tests for increased mechanosensitivity (e.g. upper limb neurodynamic tests (ULNTs and nerve palpation. Reliability reports of nerve palpation and the interpretation of neurodynamic tests are scarce. This study therefore investigated the intertester reliability of nerve palpation and ULNTs. ULNTs were interpreted based on symptom reproduction and structural differentiation. To put the reliability of these tests in perspective, a comparison with the reliability of clinical tests for nerve function was made. Methods Two experienced clinicians examined 31 patients with unilateral arm and/or neck pain. The examination included clinical tests for nerve function (sensory testing, reflexes and manual muscle testing (MMT and mechanosensitivity (ULNTs and palpation of the median, radial and ulnar nerve. Kappa statistics were calculated to evaluate intertester reliability. A meta-analysis determined an overall kappa for the domains with multiple kappa values (MMT, ULNT, palpation. We then compared the difference in reliability between the tests of mechanosensitivity and nerve function using a one-sample t-test. Results We observed moderate to substantial reliability for the tests for afferent/efferent nerve function (sensory testing: kappa = 0.53; MMT: kappa = 0.68; no kappa was calculated for reflexes due to a lack of variation. Tests to investigate mechanosensitivity demonstrated moderate reliability (ULNT: kappa = 0.45; palpation: kappa = 0.59. When compared statistically, there was no difference in reliability for tests for nerve function and mechanosensitivity (p = 0.06. Conclusion This study demonstrates that clinical tests which evaluate increased nerve mechanosensitivity and afferent/efferent nerve function have comparable moderate to

  18. First Beam and High-Gradient Cryomodule Commissioning Results of the Advanced Superconducting Test Accelerator at Fermilab

    Energy Technology Data Exchange (ETDEWEB)

    Crawford, Darren; et al.

    2015-06-01

    The advanced superconducting test accelerator at Fermilab has accelerated electrons to 20 MeV and, separately, the International Linear Collider (ILC) style 8-cavity cryomodule has achieved the ILC performance milestone of 31.5 MV/m per cavity. When fully completed, the accelerator will consist of a photoinjector, one ILC-type cryomodule, multiple accelerator R&D beamlines, and a downstream beamline to inject 300 MeV electrons into the Integrable Optics Test Accelerator (IOTA). We report on the results of first beam, the achievement of our cryomodule to ILC gradient specifications, and near-term future plans for the facility.

  19. Reliability and Responsiveness of Cardiopulmonary Exercise Testing in Fatigued Persons with Multiple Sclerosis and Low to Mild Disability

    NARCIS (Netherlands)

    Heine, Martin; van den Akker, Lizanne Eva; Verschuren, Olaf; Visser-Meily, Anne; Kwakkel, Gert

    2015-01-01

    Background Peak oxygen uptake (VO(2)peak) via cardiopulmonary exercise testing is considered the gold standard for testing aerobic capacity in healthy participants and people with various medical conditions. The reliability and responsiveness of cardiopulmonary exercise testing outcomes in persons

  20. Exploration of multi-fold symmetry element-loaded superconducting radio frequency structure for reliable acceleration of low- & medium-beta ion species

    Energy Technology Data Exchange (ETDEWEB)

    Huang, Shichun [Thomas Jefferson National Accelerator Facility, Newport News, VA (United States); Geng, Rongli [Thomas Jefferson National Accelerator Facility, Newport News, VA (United States)

    2015-09-01

    Reliable acceleration of low- to medium-beta proton or heavy ion species is needed for future high-current superconducting radio frequency (SRF) accelerators. Due to the high-Q nature of an SRF resonator, it is sensitive to many factors such as electron loading (from either the accelerated beam or from parasitic field emitted electrons), mechanical vibration, and liquid helium bath pressure fluctuation etc. To increase the stability against those factors, a mechanically strong and stable RF structure is desirable. Guided by this consideration, multi-fold symmetry element-loaded SRF structures (MFSEL), cylindrical tanks with multiple (n>=3) rod-shaped radial elements, are being explored. The top goal of its optimization is to improve mechanical stability. A natural consequence of this structure is a lowered ratio of the peak surface electromagnetic field to the acceleration gradient as compared to the traditional spoke cavity. A disadvantage of this new structure is an increased size for a fixed resonant frequency and optimal beta. This paper describes the optimization of the electro-magnetic (EM) design and preliminary mechanical analysis for such structures.