scholarly journals Extending Pressure Relief Valve Inspection Intervals by Using Statistical Analysis of Proof Test Data

2006 ◽  
Author(s):  
Robert E. Gross ◽  
Stephen P. Harris
Keyword(s):  
Statistical Analysis ◽  
Test Data ◽  
Test Results ◽  
Relief Valve ◽  
The Past ◽  
Current Test ◽  
Safety Margins ◽  
A Site ◽  
Time In Service ◽  
Site Population

This paper correlates as-received relief valve test results with current inspection intervals and presents conclusions based on statistical analysis. During the past three year period over 500 used valve proof test records from a site population of 3500 safety relief valves were acquired and reviewed. Collection and analysis of spring-loaded relief valve test data continues with the goal being to increase the test intervals within guidelines, reduce costs, and maintain safety margins. Based on current test intervals of 1–7 years, time in service appears to have a minimal effect on valve performance. Seat material and inlet size are identified as having a statistically significant impact on valve performance. An increase in TP/SP of 1–2% per year was noted for soft seated, small inlet sizes. Photographs of failed valve internals and discussion of failure causes are included.

Statistical Analysis of Fatigue Test Data

2017 ◽  
Author(s):  
Carol Johnston
Keyword(s):  
Statistical Analysis ◽  
Fatigue Strength ◽  
Cyclic Loading ◽  
Fatigue Test ◽  
Test Data ◽  
Fatigue Tests ◽  
Fatigue Performance ◽  
Test Results ◽  
Girth Welds ◽  
New Procedures

The offshore environment contains many sources of cyclic loading. Standard design S-N curves, such as those in DNVGL-RP-C203, are usually assigned to ensure a particular design life can be achieved for a particular set of anticipated loading conditions. Girth welds are often the ‘weak link’ in terms of fatigue strength and so it is important to show that girth welds made using new procedures for new projects that are intended to be used in fatigue sensitive risers or flowlines do indeed have the required fatigue performance. Alternatively, designers of new subsea connectors, used for example in tendons for tension leg platforms, mooring applications or well-heads which will experience cyclic loading in service, also wish to verify the fatigue performance of their new designs. Often operators require contractors to carry out resonance fatigue tests on representative girth welds in order to show that girth welds made using new procedures qualify to the required design S-N curve. Operators and contractors must then interpret the results, which is not necessarily straightforward if the fatigue lives are lower than expected. Many factors influence a component’s fatigue strength so there is usually scatter in results obtained when a number of fatigue tests are carried out on real, production standard components. This scatter means that it is important first to carry out the right number of tests in order to obtain a reasonable understanding of the component’s fatigue strength, and then to interpret the fatigue test results properly. A working knowledge of statistics is necessary for both specifying the test programme and interpreting the test results and there is often confusion over various aspects of test specification and interpretation. This paper describes relevant statistical concepts in a way that is accessible to non-experts and that can be used, practically, by designers. The paper illustrates the statistical analysis of test data with examples of the ‘target life’ approach (that is now included in BS7608:2014 + A1) and the equivalent approach in DNVGL-RP-C203, which uses the stress modification factor. It gives practical examples to designers of a pragmatic method that can be used when specifying test programmes and interpreting the results obtained from tests carried out during qualification programmes, which for example, aim to determine whether girth welds made using a new procedure qualify to a particular design curve. It will help designers who are tasked with specifying test programmes to choose a reasonable number of test specimens and stress ranges, and to understand the outcome when results have been obtained.

scholarly journals STUDI TEMPERAMEN SAPI BALI BERTANDUK DAN TIDAK BERTANDUK (Study on the Temperament of Polled and Horned Bali Cattle)

2020 ◽  
Vol 8 (1) ◽  
pp. 22-28
Author(s):  
Abdul Qayyum ◽  
Baco Sudirman ◽  
Zulkharnaim Zulkharnaim
Keyword(s):  
Statistical Analysis ◽  
Test Data ◽  
Cortisol Level ◽  
T Test ◽  
Covariance Analysis ◽  
Test Results ◽  
Exit Velocity ◽  
Breeding Center ◽  
Bali Cattle ◽  
Cortisol Levels

This study was aimed to determine the nature of the differences in temperament of horned and polled Bali cattle. The research was conducted in February-March 2018 in Maiwa Ranch/Maiwa Breeding Center (MBC) Enrekang regency. The research used 25 heads of Bali Cattle, 19 heads of horned Bali cattle and 6 heads of Bali polled. Temperament test data was analyzed by descriptive and cortisol levels were analyzed using T-test statistical analysis, temperance, and cortisol level test results. Data were analyzed using covariance analysis. The results of this study indicated that according to the temperament tests parameters (pen score, chute score, chute exit velocity), Bali polled were tamer than Bali horned cattle. Cortisol levels of Bali polled also observed lower than the horned Bali cattle

Reliability Testing of Pressure Relief Valves

2004 ◽  
Author(s):  
Robert E. Gross
Keyword(s):  
Test Results ◽  
Relief Valve ◽  
Pressure Relief ◽  
Data Set ◽  
System Service ◽  
Utility System ◽  
Pressure Relief Valves ◽  
Clean Air ◽  
The One ◽  
Time In Service

Following a brief description of pressure relief valves, this paper presents as-found set point test results for pressure relief valves that have been in process or utility system service. The paper examines the reliability of the relief valve to open at set pressure as a function of several key parameters, including time in service, fluid, size, and valve design (vendor). Although it may be that steam and water service valves are affected adversely by service conditions, this analysis is focused primarily on clean air/gas service. The probable correlation between fluid cleanliness and reliability is not being made, but will be considered in future studies. Valves that discharge outside allowable ASME tolerances are evaluated to determine possible causes of the deviation. Three failure case studies are presented. A final summary of test results indicates that valve reliability is not a strong function of time in service for the one-to-five year operating periods investigated. Additionally, this data set indicates that less than one percent (0.96%) of all valves pop tested at greater than 1.4 times tag set pressure.

scholarly journals Role of Paleomagnetism in the Construction of Earth’s Geographic Past

2020 ◽  
Vol 11 (1) ◽  
Author(s):  
Stephanie Robinson ◽  
Keyword(s):  
Statistical Analysis ◽  
Magnetic Particles ◽  
The Past ◽  
Northwest Africa ◽  
A Site ◽  
Magnetic Poles ◽  
Trigonometric Equations ◽  
Mesoproterozoic Era

Rocks have the ability to preserve magnetic information used in determining past geographic formations. The purpose of this report is to determine the past location of a site from a given data set’s magnetic information and the calculations found through their application to paleomagnetism. Magnetic information includes the rock sample’s location and concentration of trace magnetic particles which were used to find declination and inclination on site. The sample’s paleolatitude and paleolongitude are calculated using trigonometric equations that are derived using calculus. After a statistical analysis, these results are compared to the present day’s magnetic poles to determine the past location of the site. This location, along with the magnetic information, is combined to construct a past geographic formation that existed a billion years ago. This process reveals that the site currently found in southwest Namibia, was located near the coast of modern-day northwest Africa during the late Mesoproterozoic Era within a 95% certainty. When compared to past literature these results show the reliability and role of paleomagnetism, as well as the importance of collaboration across the geosciences.

Pemberian Umpan Balik Dalam Meningkatkan Hasil Belajar dan Minat Belajar Mahasiswa

2015 ◽  
Vol 4 (3) ◽  
Author(s):  
Seruni Seruni ◽  
Nurul Hikmah
Keyword(s):  
Information Technology ◽  
Learning Outcomes ◽  
Test Data ◽  
Random Sampling ◽  
Covariance Matrices ◽  
Test Results ◽  
Immediate Feedback ◽  
Statistics Course ◽  
Independent Variable ◽  
Descriptive Statistical Analysis

<p>The purpose of this study is to find and analyze the effect of feedback on <br />learning outcomes in mathematics and an interest in basic statistics course. The <br />population in this study are affordable Information Technology Student cademic Year 2012/2013 Semester II Indraprasta PGRI University of South Jakarta. Sample The study sample was obtained through random sampling. This study used an experimental method to the analysis using the MANOVA test. This study has three variables, consisting of: one independent variable, namely the provision of feedback (immediate and delayed), and two dependent variable is the result of interest in the study of mathematics and basic statistics course. The data was collected for the test results to learn mathematics, and a questionnaire for the interest in basic statistics course. Collected data were analyzed using the MANOVA test. Before the data were analyzed, first performed descriptive statistical analysis and test data analysis requirements (test data normality and homogeneity of covariance matrices). The results show that the learning outcomes of interest in mathematics and basic statistics course for students who are given immediate feedback higher than students given feedback delayed. <br /><br /></p>

ANALISIS PENGARUH MOTIVASI DAN KEDISIPLINAN TERHADAP PRESTASI KERJA PEGAWAI MELALUI PERILAKU KERJA PADA DKIPS PROVINSI SULAWESI BARAT

2020 ◽  
Vol 2 (1) ◽  
pp. 5-8
Author(s):  
Arnas A.M Patonangi ◽  
Cahyono Cahyono ◽  
Muhlis Ruslan
Keyword(s):  
Statistical Analysis ◽  
Work Performance ◽  
Work Motivation ◽  
Employee Performance ◽  
Partial Least Square ◽  
Least Square ◽  
Work Behavior ◽  
Test Results ◽  
Analysis Technique ◽  
Descriptive Statistical Analysis

Penelitian ini bertujuan untuk mengetahui apakah motivasi, kedisiplinan berpengaruh terhadap perilaku kerja, apakah motivasi dan kedisiplinan berpengaruh terhadap prestasi kerja, apakah perilaku kerja berpengaruh terhadap prestasi kerja, apakah motivasi berpengaruh terhadap prestasi kerja pegawai melalui perilaku kerja, serta apakah kedisiplinan berpengaruh terhadap prestasi kerja pegawai melalui perilaku kerja pada DKIPS Provinsi Sulawesi Barat. Teknik pengumpulan data melalui observasi, interview dan dokumentasi serta kuesioner. Sedangkan teknik analisis data yang digunakan adalah analisis statistic deskriptif, statistik infe-rensial, PLS (Partial Least Square), pengujian hipotesis. Hasil penelitian menemukan bahwa motivasi kerja berpengaruh positif dan signifikan terhadap perilaku kerja, Kedisiplinan berpengaruh positif dan signifikan terhadap perilaku kerja, Motivasi kerja berpengaruh positif dan signifikan terhadap prestasi kerja, Kedisiplinan berpengaruh positif dan signifikan terhadap prestasi kerja pegawai, Perilaku kerja berpengaruh positif dan signifikan terhadap prestasi kerja pegawai, hasil uji mediasi menunjukkan bahwa perilaku kerja dapat memediasi motivasi kerja terhadap prestasi kerja pegawai pada DKIPS Provinsi Sulawesi Barat, serta hasil uji mediasi menunjukkan bahwa perilaku kerja dapat memediasi disiplin kerja terhadap prestasi kerja pegawai pada DKIPS Provinsi Sulawesi Barat. This study aims to determine whether motivation, discipline affect work behavior, do motivation and discipline affect work performance, does work behavior affect work performance, does motivation affect employee performance through work behavior, and does discipline affect work performance through work behavior in West Sulawesi Province DKIPS. Data collection techniques through observation, interviews and documentation and questionnaires. While the data analysis technique used is descriptive statistical analysis, inferential statistics, PLS (Partial Least Square), hypothesis testing. The results found that work motivation has a positive and significant effect on work behavior, the discipline has a positive and significant effect on work behavior, work motivation has a positive and significant effect on work performance, the discipline has a positive and significant effect on employee work performance, work behavior has a positive and significant effect on employee work performance, mediation test results indicate that work behavior can mediate work motivation on employee work performance in DKIPS Province of West Sulawesi, and mediation test results indicate that work behavior can mediate work discipline towards employee work performance at DKIPS Province of West Sulawesi.

MONARCHS, TRAVELLERS AND EMPIRE IN THE PACIFIC'S AGE OF REVOLUTIONS

2020 ◽  
Vol 30 ◽  
pp. 77-96
Author(s):  
Sujit Sivasundaram
Keyword(s):  
Pacific Islanders ◽  
Modern World ◽  
Global History ◽  
The Past ◽  
The Pacific ◽  
Cultural Terms ◽  
The Pacific Ocean ◽  
Definition Of ◽  
The Uk ◽  
A Site

AbstractThe Pacific has often been invisible in global histories written in the UK. Yet it has consistently been a site for contemplating the past and the future, even among Britons cast on its shores. In this lecture, I reconsider a critical moment of globalisation and empire, the ‘age of revolutions’ at the end of the eighteenth century and the start of the nineteenth century, by journeying with European voyagers to the Pacific Ocean. The lecture will point to what this age meant for Pacific islanders, in social, political and cultural terms. It works with a definition of the Pacific's age of revolutions as a surge of indigeneity met by a counter-revolutionary imperialism. What was involved in undertaking a European voyage changed in this era, even as one important expedition was interrupted by news from revolutionary Europe. Yet more fundamentally vocabularies and practices of monarchy were consolidated by islanders across the Pacific. This was followed by the outworkings of counter-revolutionary imperialism through agreements of alliance and alleged cessation. Such an argument allows me, for instance, to place the 1806 wreck of the Port-au-Prince within the Pacific's age of revolutions. This was an English ship used to raid French and Spanish targets in the Pacific, but which was stripped of its guns, iron, gunpowder and carronades by Tongans. To chart the trajectory from revolution and islander agency on to violence and empire is to appreciate the unsettled paths that gave rise to our modern world. This view foregrounds people who inhabited and travelled through the earth's oceanic frontiers. It is a global history from a specific place in the oceanic south, on the opposite side of the planet to Europe.

Modeling the Tensile Behaviour of a SiC/SiC Composite by Master Curves

2000 ◽  
Author(s):  
J. Shi
Keyword(s):  
Master Curve ◽  
Ceramic Matrix Composites ◽  
Test Material ◽  
Tensile Behaviour ◽  
Matrix Composites ◽  
Test Results ◽  
Master Curves ◽  
The Past ◽  
Test Parameters ◽  
Tensile Data

Scatter in test results is common for relatively brittle materials such as ceramic matrix composites. The scatter may come from differences in material processing conditions, specimen machining/handling and from variations in test parameters for nominally the same test material. Large scatter in test results makes material modeling difficult. In the past, master curve concepts have been proposed to reduce scatter in tensile data and to interpret fatigue/creep results. In this paper, one such concept is examined in detail by applying it to the recent tensile test results of a SiC/SiC composite. It was found that the way to construct master curves did not apply to the CMC studied and thus a new master curve was developed to better represent the tensile data. In addition, the test data were analysed statistically based on the new master curve.

scholarly journals The elusive parasite: comparing macroscopic, immunological, and genomic approaches to identifying malaria in human skeletal remains from Sayala, Egypt (third to sixth centuries AD)

2021 ◽  
Vol 13 (7) ◽  
Author(s):  
Alvie Loufouma Mbouaka ◽  
Michelle Gamble ◽  
Christina Wurst ◽  
Heidi Yoko Jäger ◽  
Frank Maixner ◽  
...  
Keyword(s):  
Diagnostic Tests ◽  
Sample Selection ◽  
Human Remains ◽  
Rapid Diagnostic Tests ◽  
Skeletal Remains ◽  
Pathological Changes ◽  
Human Skeletal Remains ◽  
The Past ◽  
A Site ◽  
Capture Sequencing

AbstractAlthough malaria is one of the oldest and most widely distributed diseases affecting humans, identifying and characterizing its presence in ancient human remains continue to challenge researchers. We attempted to establish a reliable approach to detecting malaria in human skeletons using multiple avenues of analysis: macroscopic observations, rapid diagnostic tests, and shotgun-capture sequencing techniques, to identify pathological changes, Plasmodium antigens, and Plasmodium DNA, respectively. Bone and tooth samples from ten individuals who displayed skeletal lesions associated with anaemia, from a site in southern Egypt (third to sixth centuries AD), were selected. Plasmodium antigens were detected in five of the ten bone samples, and traces of Plasmodium aDNA were detected in six of the twenty bone and tooth samples. There was relatively good synchronicity between the biomolecular findings, despite not being able to authenticate the results. This study highlights the complexity and limitations in the conclusive identification of the Plasmodium parasite in ancient human skeletons. Limitations regarding antigen and aDNA preservation and the importance of sample selection are at the forefront of the search for malaria in the past. We confirm that, currently, palaeopathological changes such as cribra orbitalia are not enough to be certain of the presence of malaria. While biomolecular methods are likely the best chance for conclusive identification, we were unable to obtain results which correspond to the current authentication criteria of biomolecules. This study represents an important contribution in the refinement of biomolecular techniques used; also, it raises new insight regarding the consistency of combining several approaches in the identification of malaria in past populations.

scholarly journals The two-sided spectacle at the border: Frontex, NGOs and the theatres of sovereignty

2021 ◽  
pp. 136248062110078
Author(s):  
Katja Franko
Keyword(s):  
Visual Analysis ◽  
Ethical Dilemmas ◽  
Moral Authority ◽  
Living Conditions ◽  
Coast Guard ◽  
The Past ◽  
Southern Mediterranean ◽  
The Mediterranean ◽  
A Site ◽  
Previous Scholarship

The Southern Mediterranean border has in the past decade become one of the most deeply contested political spaces in Europe and has been described as a site of the border spectacle. Drawing on textual and visual analysis of Twitter messages by two of the most prominent actors in the field, the European Border and Coast Guard Agency, Frontex, and the humanitarian and medical NGO Médecins Sans Frontières, the article examines the split nature of the Mediterranean border which is, among others, visible in radically different narratives about migrants’ journeys, border deaths and living conditions. The findings challenge previous scholarship about convergence of humanitarianism and policing. The two actors are waging a fierce media battle for moral authority, where they use widely diverging strategies of claiming authority, each of which carries a particular set of ethical dilemmas.

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