scholarly journals Evaluating AOV and MOV Performance

2017 ◽  
Author(s):  
Tom Walker ◽  
Nick Camilli
Keyword(s):  
The Past ◽  
Design Basis ◽  
Predictive Methods ◽  
Recent Project ◽  
Valve Operation ◽  
Rate Of Loading

Calculating margin for valve operation under design basis conditions requires evaluation of the stem loads required to operate the valve and the load capability of the actuator. These evaluations require justified and validated methodologies with verified inputs to implement the methodologies. The lack of validated methodologies in the past led to plant events and issues that prompted three NRC generic letters for MOVs and numerous generic correspondence documents from the NRC on AOV and MOV performance. Over the past 25 years, EPRI has performed extensive research to better understand the performance of valves and power operators. This research has been used to develop predictive methods for the evaluation of valve required operating loads and actuator output capability. This paper summarizes EPRI’s research related to the development of predictive methodologies for valves and power operators and methods that are available, specifically methods for: • Predicting required operating loads under design basis conditions, • Predicting actuator output capability, • Addressing thermal binding of gate valves, and • Addressing the rate-of-loading phenomenon for MOVs. This paper also describes a recent project to develop and validate a method for predicting the required thrust to overcome friction between the valve disk and body due to disk side-loading in cage-guided balanced disk globe valves. Paper published with permission.

scholarly journals Questioning the Subject in Biographical Interviewing

2006 ◽  
Vol 11 (3) ◽  
pp. 16-25 ◽  
Author(s):  
Jennifer Harding
Keyword(s):  
Young People ◽  
University Students ◽  
The Self ◽  
Subject Positions ◽  
Training Video ◽  
The Past ◽  
Emotional Aspects ◽  
The Subject ◽  
Recent Project

This paper considers how different approaches to interviewing and styles of questioning produce different sorts of biographical subjects and accounts. It compares styles of biographical interview (chronological and narrative) and types of question (narrative and explanatory), and presents an approach, which treats the interview as a collaborative co-production primarily concerned with the present and subjectivity, rather than the past and fact. It also considers how biographical interviewing may direct and contain narratives of the self through the subject positions it creates and offers interviewees. Discussion is grounded in reflection on a recent project involving university students in interviewing young people leaving care about their care experiences and making a training video for professionals. The paper highlights the inter-subjective and emotional aspects of interviewing in this context.

What can the Twenty-First Century Church of England Learn from the Victorians?

Ecclesiology ◽  
2013 ◽  
Vol 9 (2) ◽  
pp. 205-222
Author(s):  
John Wolffe
Keyword(s):  
Nineteenth Century ◽  
Historical Perspective ◽  
Church Attendance ◽  
Church Of England ◽  
First Century ◽  
Constructive Thinking ◽  
The Past ◽  
Critical Engagement ◽  
Ambivalent Attitude ◽  
Recent Project

Present-day Anglicans have an ambivalent attitude to the Victorians. There are, however, as illustrated by a recent project in the diocese of London, important ways in which critical engagement with the past can inform constructive thinking in contemporary churches. In particular an understanding of patterns of church attendance in the nineteenth century provides context for evaluating more recent statistics, while knowledge of the circumstances leading to the building of Victorian churches can inform decisions about their present-day use. Awareness of the sometimes bitterly divided Victorian church helps to set current internal Anglican tensions in proportion, while a long historical perspective can be of assistance in the setting of realistic expectations in the present.

scholarly journals The past and future human impact on mammalian diversity

2020 ◽  
Vol 6 (36) ◽  
pp. eabb2313 ◽  
Author(s):  
Tobias Andermann ◽  
Søren Faurby ◽  
Samuel T. Turvey ◽  
Alexandre Antonelli ◽  
Daniele Silvestro
Keyword(s):  
Human Impact ◽  
Fossil Record ◽  
Human Population ◽  
Biodiversity Crisis ◽  
The Past ◽  
Extinction Rates ◽  
Current Trends ◽  
Predictive Methods ◽  
Near Future ◽  
Better Than

To understand the current biodiversity crisis, it is crucial to determine how humans have affected biodiversity in the past. However, the extent of human involvement in species extinctions from the Late Pleistocene onward remains contentious. Here, we apply Bayesian models to the fossil record to estimate how mammalian extinction rates have changed over the past 126,000 years, inferring specific times of rate increases. We specifically test the hypothesis of human-caused extinctions by using posterior predictive methods. We find that human population size is able to predict past extinctions with 96% accuracy. Predictors based on past climate, in contrast, perform no better than expected by chance, suggesting that climate had a negligible impact on global mammal extinctions. Based on current trends, we predict for the near future a rate escalation of unprecedented magnitude. Our results provide a comprehensive assessment of the human impact on past and predicted future extinctions of mammals.

Observations of the continuum near the galactic centre

1967 ◽  
Vol 31 ◽  
pp. 405
Author(s):  
F. J. Kerr
Keyword(s):  
Galactic Centre ◽  
The Past ◽  
Centre Region ◽  
The Continuum

A continuum survey of the galactic-centre region has been carried out at Parkes at 20 cm wavelength over the areal11= 355° to 5°,b11= -3° to +3° (Kerr and Sinclair 1966, 1967). This is a larger region than has been covered in such surveys in the past. The observations were done as declination scans.

The Origin of the Moon and its Relationship to the Origin of the Solar System

1962 ◽  
Vol 14 ◽  
pp. 133-148 ◽  
Author(s):  
Harold C. Urey
Keyword(s):  
Solar System ◽  
The Moon ◽  
The Past ◽  
The Earth ◽  
Short Period ◽  
Origin Of The Moon

During the last 10 years, the writer has presented evidence indicating that the Moon was captured by the Earth and that the large collisions with its surface occurred within a surprisingly short period of time. These observations have been a continuous preoccupation during the past years and some explanation that seemed physically possible and reasonably probable has been sought.

On The Possibility of an Autonomous History of Modern Southeast Asia

1961 ◽  
Vol 2 (2) ◽  
pp. 73-105 ◽  
Author(s):  
John R. W. Small
Keyword(s):  
Southeast Asia ◽  
Contemporary History ◽  
The Past ◽  
History Of

It is generally accepted that history is an element of culture and the historian a member of society, thus, in Croce's aphorism, that the only true history is contemporary history. It follows from this that when there occur great changes in the contemporary scene, there must also be great changes in historiography, that the vision not merely of the present but also of the past must change.

Stellar Evolution

1962 ◽  
Vol 11 (02) ◽  
pp. 137-143
Author(s):  
M. Schwarzschild
Keyword(s):  
Solar System ◽  
Stellar Evolution ◽  
Space Craft ◽  
New Techniques ◽  
Substantial Body ◽  
Individual Stars ◽  
The Past ◽  
Evolution Of Galaxies ◽  
History Of ◽  
Fast Flow

It is perhaps one of the most important characteristics of the past decade in astronomy that the evolution of some major classes of astronomical objects has become accessible to detailed research. The theory of the evolution of individual stars has developed into a substantial body of quantitative investigations. The evolution of galaxies, particularly of our own, has clearly become a subject for serious research. Even the history of the solar system, this close-by intriguing puzzle, may soon make the transition from being a subject of speculation to being a subject of detailed study in view of the fast flow of new data obtained with new techniques, including space-craft.

Novae in the Magellanic Clouds

1979 ◽  
Vol 46 ◽  
pp. 96-101
Author(s):  
J.A. Graham
Keyword(s):  
Large Magellanic Cloud ◽  
Magellanic Cloud ◽  
Magellanic Clouds ◽  
University Of Michigan ◽  
The Past ◽  
Spectroscopic Information ◽  
Objective Prism ◽  
The University ◽  
Small Cloud ◽  
Low Dispersion

During the past several years, a systematic search for novae in the Magellanic Clouds has been carried out at Cerro Tololo Inter-American Observatory. The Curtis Schmidt telescope, on loan to CTIO from the University of Michigan is used to obtain plates every two weeks during the observing season. An objective prism is used on the telescope. This provides additional low-dispersion spectroscopic information when a nova is discovered. The plates cover an area of 5°x5°. One plate is sufficient to cover the Small Magellanic Cloud and four are taken of the Large Magellanic Cloud with an overlap so that the central bar is included on each plate. The methods used in the search have been described by Graham and Araya (1971). In the CTIO survey, 8 novae have been discovered in the Large Cloud but none in the Small Cloud. The survey was not carried out in 1974 or 1976. During 1974, one nova was discovered in the Small Cloud by MacConnell and Sanduleak (1974).

Immunoferritin localization of intracellular antigens in positively stained frozen sections

1978 ◽  
Vol 36 (2) ◽  
pp. 168-169
Author(s):  
K. T. Tokuyasu
Keyword(s):  
Surface Tension ◽  
Water Surface ◽  
Thin Layers ◽  
The Other ◽  
Positive Staining ◽  
Frozen Sections ◽  
The Past ◽  
Ultrathin Frozen Sections ◽  
Definition Of

During the past investigations of immunoferritin localization of intracellular antigens in ultrathin frozen sections, we found that the degree of negative staining required to delineate u1trastructural details was often too dense for the recognition of ferritin particles. The quality of positive staining of ultrathin frozen sections, on the other hand, has generally been far inferior to that attainable in conventional plastic embedded sections, particularly in the definition of membranes. As we discussed before, a main cause of this difficulty seemed to be the vulnerability of frozen sections to the damaging effects of air-water surface tension at the time of drying of the sections.Indeed, we found that the quality of positive staining is greatly improved when positively stained frozen sections are protected against the effects of surface tension by embedding them in thin layers of mechanically stable materials at the time of drying (unpublished).

The Use of Advanced Analytical Techniques for Characterization of the Chemical, Physical, and Crystallographic Nature of a Surface

1973 ◽  
Vol 31 ◽  
pp. 132-133 ◽  
Author(s):  
R. E. Herfert
Keyword(s):  
Surface Characterization ◽  
Analytical Techniques ◽  
X Ray Diffraction ◽  
Depth Of Penetration ◽  
X Ray ◽  
The Past ◽  
Transmission Electron ◽  
Scanning Electron

Studies of the nature of a surface, either metallic or nonmetallic, in the past, have been limited to the instrumentation available for these measurements. In the past, optical microscopy, replica transmission electron microscopy, electron or X-ray diffraction and optical or X-ray spectroscopy have provided the means of surface characterization. Actually, some of these techniques are not purely surface; the depth of penetration may be a few thousands of an inch. Within the last five years, instrumentation has been made available which now makes it practical for use to study the outer few 100A of layers and characterize it completely from a chemical, physical, and crystallographic standpoint. The scanning electron microscope (SEM) provides a means of viewing the surface of a material in situ to magnifications as high as 250,000X.

Sign in / Sign up

Export Citation Format

Share Document