HRSG Header Creep-Assessment Through a Procedure for the Italian Code Application and Comparison With the American Standard

2015 ◽  
Author(s):  
Ottaviano Grisolia ◽  
Lorenzo Scano
Keyword(s):  
Weight Fraction ◽  
External Loading ◽  
Creep Life ◽  
Element Analysis ◽  
Creep Analysis ◽  
Level 3 ◽  
Approach Method ◽  
American Standard ◽  
Level 1 ◽  
Minimum Stress

Lower headers of bottom-supported heat-recovery steam generators (HRSG) may be critical because of their longitudinal dimensions, thermal expansions and external loading (the harp’s weight): Present work considers the creep analysis of the high-temperature-section (superheater /reheater) headers: they may be critical because of the long continued service (175000 hours or twenty years), larger dimensions and the external loads, including a negligible steam-drum weight fraction. The aim of the work is to compare life results from the Italian creep code with those predicted by the American standard API 579-1. This work also checks the compatibility of results coming from the two polynomial models in both Italian and API 579-1 procedures. Classical methods, applied using both ASME and Italian pressure formulae, show that, as for the evaporator-section header, the pressure contribution to longitudinal stress may be greater than bending alone; considering now the increased header’s weight, the stress ratio is also comparable to the evaporator’s. Consistency of results from numerical-model stress analysis (elastic) is good, confirming the pressure contribution is greatest. For the Level-1 assessment (B31.1 stresses), the Italian procedure and the API 579-1 return consistent creep life results, though the API 579-1 results appear more conservative than the Italian-procedure’s. Level-1 assessment, acted through an elastic finite element analysis (FEA), uses Larson-Miller parameter (LMP)-approach method with minimum stress-to-rupture data: the Italian procedure and API 579-1 return consistent creep life results when evaluated on the tubehole branch side, Italian-procedure’s appearing little more conservative than the API 579-1’s. For the Level-2 assessment (FEA stresses), again the Italian procedure and the API 579-1 return consistent creep life results with the Italian-procedure ones again a little more conservative than the API 579-1’s for both sides of the intersection. Level-3 assessment (incorporating creep, plasticity and relaxation) shows (short) creep lives similar to Italian-procedure’s.

FFS Assessment of Pressurized Equipment Utilizing a Thickness Mapping Tool

2016 ◽  
Author(s):  
Benjamin Hantz ◽  
Venkata M. K. Akula ◽  
John Leroux
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
Response Prediction ◽  
Accurate Estimate ◽  
Pressure Vessels ◽  
The Finite Element Method ◽  
Element Analysis ◽  
Level 3 ◽  
Level 1 ◽  
Element Method

For pressure vessels, loss of thickness detected during scheduled maintenance utilizing UT scans can be assessed based on Level 1 or 2 analyses as per API 579 guidelines. However, Level 1 and 2 analyses can point to excessively conservative assessments. Level – 3 assessments utilizing the finite element method can be performed for a more accurate estimate of the load carrying capacity of the corroded structure. However, for a high fidelity structural response prediction using the finite element method, the characteristics of the model must be accurately represented. Although the three nonlinearities, namely, the geometric, material, and contact nonlinearities can be adequately included in a finite element analysis, procedures to accurately include the thickness measurements are not readily available. In this paper, a tool to map thicknesses obtained from UT scans onto a shell based finite element models, to perform Level – 3 analyses is discussed. The tool works in conjunction with Abaqus/CAE and is illustrated for two different structures following the elastic-plastic analysis procedure outlined in the API 579 document. The tool is intended only as a means to reduce the modeling time associated with mapping thicknesses. The results of the analyses and insights gained are presented.

Steam Generator Grade P91 Steel Components Creep-Assessment Through a Procedure for the Italian Code Application and Comparison With the ECCC Recommendations, American Standard

2017 ◽  
Author(s):  
Ottaviano Grisolia ◽  
Lorenzo Scano
Keyword(s):  
High Temperature ◽  
Steam Generator ◽  
Polynomial Function ◽  
Steam Generators ◽  
Steel Microstructure ◽  
Operation Temperature ◽  
Creep Analysis ◽  
Material Creep ◽  
Level 3 ◽  
American Standard

ASTM A 335-Grade P91 components of steam generators may be critical because of possible steel microstructure changes and/or embrittlement due to the FATT increase during service at high temperature: both phenomena may worsen the material creep behavior globally. Operation temperatures below 600°C such as in the worked case considered herein should be less critical; nevertheless, the worked case plan has included additional controls on microstructure also to have a reference for the future. Present study considers for the worked case steam generator the creep analysis of high-temperature-section (superheater / reheater) two components, outflow tubing and manifold: they may be critical because of the long continued service (110,000 hours or twelve years) and loading conditions (maximum operation temperature and applied stress at the intersection). Aim of the work is to compare life results from the Italian creep code with those predicted by the API 579-1; it also checks compatibility of results from the polynomial models in Italian, ECCC and API 579-1 procedures. Life results based on the Italian-code polynomial function are consistent with those based on the polynomial function proposed in ECCC: With preliminary stresses from pressure formulas, life estimates are a bit more conservative than the ECCC model’s. Finally, life results obtained through the API 579-1 Level 3 assessment appear consistent with those predicted by the Italian creep code, ECCC recommendations application.

Application of the Creep Italian Standard Through an Automatic Procedure and Comparison With the American Code

2013 ◽  
Author(s):  
Ottaviano Grisolia ◽  
Lorenzo Scano
Keyword(s):  
Residual Life ◽  
High Energy ◽  
Sensitive Material ◽  
Element Analysis ◽  
Operation Temperature ◽  
Omega Method ◽  
First Choice ◽  
Level 3 ◽  
Level 1 ◽  
Critical Components

A previously-developed computer program [1] features the least-squares analysis for finding the best fitting model’s regression coefficients: The analysis is acted on points (test temperature, ultimate strength at 100000 hours) available in literature for any creep-sensitive material. The automatic procedure gives time to rupture at operation temperature directly through the model chosen for the curve Larson-Miller parameter (LMP) – stress. It applies the first-choice method in the Section II of the guideline [2] to the Italian technical procedure for creep-operated pressure vessel components [3]. Aim of the present work is to compare the results of the Italian code with those predicted by the API 579-1 standard [4]. Comparison is on data gathered by one author in his previous work [5]. That investigated a high energy pipeline after 230000 hours of service and calculated critical components’ life through an API 579-1 Level-3 assessment. Present study uses stresses from standard analysis based on B31.1 code [6] and from a finite element analysis (FEA, elastic and plastic): it finds out the residual life of three components, a 90-LR bend and two tees. Besides, it carries out creep assessment according to the Italian procedure and API 579-1 (Level 1 to 3); the former is LMP-approach based whereas the latter uses both LMP and the Omega methods. For the Level-1 assessment (B31.1 stresses), the Italian procedure and the API 579-1 return consistent results. Acting a Level-2 assessment through an elastic FEA, results are consistent only when the API 579-1 analysis adopts the Omega Method. The LMP-approach method (minimum stress to rupture data) shows instead more conservative results. API 579-1 Level-3 assessment incorporates creep, plasticity and relaxation: When compared with the Italian procedure it predicts longer creep lives (up to a factor of ten).

Anwendung des 10-Gruppenklassifikationssystems nach Robson für den Vergleich eines Perinatalzentrums Level 1 mit einem Level-3-Zentrum

2020 ◽  
Author(s):  
C Pulvermacher ◽  
P van de Vondel ◽  
L Gerzen ◽  
U Gembruch ◽  
W Merz
Keyword(s):  
Level 3 ◽  
Level 1

EVALUASI PELATIHAN DI PT. PUPUK KUJANG CIKAMPEK

2018 ◽  
Vol 3 (2) ◽  
Author(s):  
Lania Muharsih ◽  
Ratih Saraswati
Keyword(s):  
Training Evaluation ◽  
Work Productivity ◽  
Learning Behavior ◽  
Level 3 ◽  
Level 1 ◽  
Four Levels ◽  
A Company ◽  
Level 2 ◽  
Evaluation Sheet ◽  
Assessment Factor

This study aims to determine the training evaluation at PT. Kujang Fertilizer. PT. Pupuk Kujang is a company engaged in the field of petrochemicals. Evaluation sheet of PT. Fertilizer Kujang is made based on Kirkpatrick's theory which consists of four levels of evaluation, namely reaction, learning, behavior, and results. At level 1, namely reaction, in the evaluation sheet is in accordance with the theory of Kirkpatrick, at level 2 that is learning should be held pretest and posttest but only made scale. At level 3, behavior, according to theory, but on assessment factor number 3, quantity and work productivity should not need to be included because they are included in level 4. At level 4, that is the result, here is still lacking to get a picture of the results of the training that has been carried out because only based on answers from superiors without evidence of any documents.   Keywords: Training Evaluation, Kirkpatrick Theory.    Penelitian ini bertujuan mengetahui evaluasi training di PT. Pupuk Kujang. PT. Pupuk Kujang merupakan perusahaan yang bergerak di bidang petrokimia. Lembar evaluasi PT. Pupuk Kujang dibuat berdasarkan teori Kirkpatrick yang terdiri dari empat level evaluasi, yaitu reaksi, learning, behavior, dan hasil. Pada level 1 yaitu reaksi, di lembar evaluasi tersebut sudah sesuai dengan teori dari Kirkpatrick, pada level 2 yaitu learning seharusnya diadakan pretest dan posttest namun hanya dibuatkan skala. Pada level 3 yaitu behavior, sudah sesuai teori namun pada faktor penilaian nomor 3 kuantitas dan produktivitas kerja semestinya tidak perlu dimasukkan karena sudah termasuk ke dalam level 4. Pada level 4 yaitu hasil, disini masih sangat kurang untuk mendapatkan gambaran hasil dari pelatihan yang sudah dilaksanakan karena hanya berdasarkan dari jawaban atasan tanpa bukti dokumen apapun.   Kata kunci: Evaluasi Pelatihan, Teori Kirkpatrick.

scholarly journals 905 How to prioritise patients and safely resume elective surgery during the Covid-19 pandemic

2021 ◽  
Vol 108 (Supplement_2) ◽  
Author(s):  
H Subbiah Ponniah ◽  
M Ahmed ◽  
T Edwards ◽  
J Cobb ◽  
E Dean ◽  
...  
Keyword(s):  
Patient Safety ◽  
High Risk ◽  
Orthopaedic Surgery ◽  
Elective Surgery ◽  
Paediatric Patients ◽  
Level 3 ◽  
Level 1 ◽  
Surgical Unit

Abstract Introduction There are now over 2.5 million NHS patients awaiting elective surgery, with the most in orthopaedics. We present an algorithm and results for safely and equitably restarting surgery at COVID-light sites. Method An MDT applied the COVID-19 Algorithm for Resuming Elective Surgery (CARES) on 1169 patients awaiting elective orthopaedic surgery. It assessed safety, procedural efficacy, and biopsychosocial factors, to prioritise patients. They were assigned to five categories and underwent surgery at one of three COVID-light sites (1. access to HDU/ITU/Paediatrics/specialist equipment, 2. an NHS elective surgical unit and 3. a private elective surgical unit). Results 21 ‘Urgent’ patients received expedited care; 118 were Level 1/2; 222 were Level 3; 808 were Level 4. In 6 weeks, 355 surgeries were performed, with Urgent and Level 1/2 cases performed soonest (mean 18 days, p < 0.001). 33 high-risk/complex/paediatric patients had surgery at Site 1 and the rest at Sites 2 and 3. No patients contracted COVID-19 within 2 weeks of surgery. Conclusions We validated a widely generalisable model to facilitate resumption of elective surgery in COVID-light sites. It enabled surgery for patients in most suffering, undergoing the most efficacious procedures and/or at highest risk of deterioration, without compromising patient-safety.

scholarly journals An Atmospheric Visibility Grading Method Based on Ensemble Learning and Stochastic Weight Average

Atmosphere ◽  
2021 ◽  
Vol 12 (7) ◽  
pp. 869
Author(s):  
Xiuguo Zou ◽  
Jiahong Wu ◽  
Zhibin Cao ◽  
Yan Qian ◽  
Shixiu Zhang ◽  
...  
Keyword(s):  
Ensemble Learning ◽  
Traffic Accidents ◽  
Feature Sets ◽  
Atmospheric Visibility ◽  
Average Accuracy ◽  
Level 3 ◽  
Visual Characteristics ◽  
Level 1 ◽  
Grading Model ◽  
Level 2

In order to adequately characterize the visual characteristics of atmospheric visibility and overcome the disadvantages of the traditional atmospheric visibility measurement method with significant dependence on preset reference objects, high cost, and complicated steps, this paper proposed an ensemble learning method for atmospheric visibility grading based on deep neural network and stochastic weight averaging. An experiment was conducted using the scene of an expressway, and three visibility levels were set, i.e., Level 1, Level 2, and Level 3. Firstly, the EfficientNet was transferred to extract the abstract features of the images. Then, training and grading were performed on the feature sets through the SoftMax regression model. Subsequently, the feature sets were ensembled using the method of stochastic weight averaging to obtain the atmospheric visibility grading model. The obtained datasets were input into the grading model and tested. The grading model classified the results into three categories, with the grading accuracy being 95.00%, 89.45%, and 90.91%, respectively, and the average accuracy of 91.79%. The results obtained by the proposed method were compared with those obtained by the existing methods, and the proposed method showed better performance than those of other methods. This method can be used to classify the atmospheric visibility of traffic and reduce the incidence of traffic accidents caused by atmospheric visibility.

The Magical Number Two, Plus or Minus One: Some Limits on our Capacity for Processing Musical Information

2002 ◽  
Vol 6 (2) ◽  
pp. 185-219 ◽  
Author(s):  
Adam Ockelford
Keyword(s):  
Cognitive Processing ◽  
General Principle ◽  
Empirical Work ◽  
Theoretical Framework ◽  
Musical Structure ◽  
Magical Number ◽  
Level 3 ◽  
Level 1 ◽  
Level 2

Like all fields of human artistic endeavour, music is constrained by our cognitive processing requirements and limitations (Swain, 1986; Lerdahl, 1988; Huron, 2001). This articleconsiders particular forms of constraint pertaining to the relationships that the structure-seeking mind (subconsciously) fabricates between perceived musical events. It is proposed that 2±1 may be a universal limitation pertaining to the level of relationships so ideated. That is, in terms of Lewin'S (1987) theoretical framework in which “intervals” can be intuited between the “elements” of musical “spaces”, it is posited that the cognition of musical structure occurs either through intervals (level 1), through intervals between these (level 2), or — in some circumstances — through intervals between these(level 3). This proposition is explored through the psychomusicological model developed by Ockelford (1991, 1993, 1999), which too analyses musical structure in terms of the relationships that may be cognised between its discrete perceptual components. In particular, the model identifies a type of cognitive link through which events (at any level) arefelt to imply others the same or similar — through so-called “zygonic” relationships. This theory suggests a further general principle: that the highest level of relationship inoperation at any given point must be zygonic if the music is to be structurally coherent. Evidence for this, and for the limit on the level of relationships of 2±1, is offeredthrough a series of musical examples, which illustrate a variety of musical organisation in action. Finally, empirical work is suggested to explore further the theoretical ideas that arepresented here.

Systems biology markup language: Level 2 and beyond

2003 ◽  
Vol 31 (6) ◽  
pp. 1472-1473 ◽  
Author(s):  
A. Finney ◽  
M. Hucka
Keyword(s):  
Systems Biology ◽  
Computational Models ◽  
Chemical Species ◽  
Biochemical Networks ◽  
Markup Language ◽  
Exchange Format ◽  
Systems Biology Markup Language ◽  
Level 3 ◽  
Level 1 ◽  
Level 2

The SBML (systems biology markup language) is a standard exchange format for computational models of biochemical networks. We continue developing SBML collaboratively with the modelling community to meet their evolving needs. The recently introduced SBML Level 2 includes several enhancements to the original Level 1, and features under development for SBML Level 3 include model composition, multistate chemical species and diagrams.

Knowledge Acquired from Learning: New Evidence of Hierarchical Conceptualization

1994 ◽  
Vol 79 (2) ◽  
pp. 975-993 ◽  
Author(s):  
Alberto Montare
Keyword(s):  
Sex Differences ◽  
Knowledge Acquisition ◽  
Reversal Learning ◽  
Concept Formation ◽  
Learning Task ◽  
Learning Rates ◽  
Level 3 ◽  
Level 1 ◽  
New Evidence ◽  
Level 2

Following successful inductive acquisition of procedural cognition of a discrimination-reversal learning task, 50 female and 50 male undergraduates articulated declarative cognizance of knowledge acquired from learning. Tests of four hypotheses showed that (1) increasingly higher levels of declarative cognizance were associated with faster learning rates, (2) six new cases of cognition-without-cognizance were observed, (3) students presumably using secondary signalization learned faster than those presumably using primary signalization, and (4) no sex differences in learning rates or declarative cognizance were observed. The notion that explicit levels of declarative cognizance may represent implicit hierarchical conceptualization comprised of four systems of knowledge acquisition led to the conclusions that primary signalization may account for inductive senscept formation at Level 1 and for inductive percept formation at Level 2, whereas emergent secondary signalization may account for inductive precept formation at Level 3 and for inductive concept formation at Level 4.

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