bluuebunny/crossref_metadata_2025_split huggingface dataset:
Nonuraemic nonfatal idiopathic calciphylaxis in a kitten
Authors: Thom Nina , Er Elif , Reinacher Manfred 
Published: August 2013

BackgroundCalciphylaxis is a rare cutaneous disorder, characterized by vascular calcification and progressive skin necrosis, not yet described in cats. It is scarcely reported in animals, mostly due to iatrogenic or uraemic disturbances of the calcium–phosphate balance. In human patients, it is most commonly seen with end‐stage renal disease, but several nonuraemic disorders, including inherited dysfunctions of tissue calcification inhibitors, have also been described.Hypothesis/ObjectivesTo describe a case of nonuraemic calciphylaxis in a cat.AnimalsA 10‐week‐old male domestic short hair kitten was presented with hyperacute skin lesions. Initial dermatological signs were characterized by sharp demarcated erosions and ulcerations on the face, including the nasal planum and lips. Cutaneous lesions rapidly progressed into thick crusts with ulcerations, involving parts of the face and pinna as well as abdominal skin.MethodsComplete blood count, serum chemistry profile, urinalysis, parathyroid hormone measurement and histopathological examination of skin biopsies.ResultsHistopathology from newly developed abdominal skin lesions revealed severe epidermal necrosis and calcification, multifocal pannicular calcification and calcified subcutaneous vessels, supporting a diagnosis of calciphylaxis. Treatment consisted of systemic and topical antimicrobials, analgesics, pentoxifylline, Lantharenol®, sodium thiosulfate and vitamin K. After initiation of therapy, no further progression was noticed; all medications could be discontinued eventually, and no relapse was seen in the following 2 years.Conclusions and clinical importanceCalciphylaxis should be considered as a differential diagnosis for ulcerative cutaneous disorders in young cats. More information on this disease is needed to elucidate the pathomechanism.
Estimated SIL Levels and Risk Comparisons for Relief Valves as a Function of Time-in-Service
Authors: Mitchell Emily M. , Gross Robert E. , Harris Stephen P. 
Published: August 2013

The probability of failure on demand for spring-operated pressure relief valves (SORVs) is estimated by applying the Fréchet and Weibull probability distributions using proof test data from the United States Department of Energy’s Savannah River Site (SRS) in Aiken, South Carolina. The data can be accessed through the Center for Chemical Process Safety (CCPS) Process Equipment Reliability Database (PERD). The probability distributions enable the evaluation of risk, estimation of ANSI/ISA-84.00.01 Safety Integrity Levels (SILs), and the impact of potential modifications of the maintenance plan.
Current SRS practices are reviewed, and recommendations are made for risk-based adjustments to the maintenance plan. Subsets of valves are identified in which maintenance times can be extended and in which increased safety margins may be needed.
Effect of Pre-Strain on Mechanical Properties of Pressure Vessel Grades: Assessment of Stress Relieving/Post Weld Heat Treatments Efficiency at Regenerating Properties
Authors: Heritier Deborah , Pillot Sylvain , Corre Stéphanie , Chauvy Cédric , Toussaint Patrick 
Published: August 2013

During fabrication of large pressure vessels, thick plates are submitted to numerous process phases that may affect the initial (i.e. as delivered) properties of the material. Regarding the advantages (both technical and economical) of cold forming process, this technique is largely preferred and widely spread.
Modern forming presses and rollers are now sufficiently powerful to roll very thick plates (typically up to 250mm thick) devoted to ultra-heavy pressure equipments. As force does not really constitute a limitation anymore, current limitations are now focusing on maximum admissible strain in materials. This particular limit is linked to:
- Intrinsic maximum deformation admissible by the material (given by tensile tests),
- Regulation rules coming from construction codes.
From a practical point of view, the actual limitation comes from the construction codes that are very severe.
Main codes (ASME Boilers and Pressure Vessels Construction Code from American side and EN 13445 Unfired Pressure Vessels Construction Code from European side) both give a limit equal to 5% strain for using material in “as-strained” condition without any heat treatment. Above this limit, the philosophy differs from one code to another.
While European Code requires a full quality treatment of the strained material (Normalisation or Austenitization / Tempering), American code only requires Tempering, allowing fabricators the possibility of using the mandatory Post Weld Heat Treatment (PWHT) (needed by welded zones) as a tempering treatment to improve welded zone toughness and to regenerate material properties.
The purpose of this contribution is to review the effect of pre-strain on mechanical properties (Hardness, Tensile and Toughness transition curves) for different strain levels and to evaluate the ability of typical PWHT to regenerate material properties. Results presented in this paper are based on both recent studies on the most common up-to-date materials as well as on historical data collected in the last decades.
This study clearly demonstrates that the required PWHT is efficient enough to regenerate all material properties and that there is no need to apply a full quality heat treatment, even for the highest level of strain. This benefits both the fabricator and the end user as it implies reducing costs and risks of components deformation while maintaining the necessary level of service properties.
CMOD Compliance of B×B Single Edge Bend Specimens
Authors: Shen Guowu , Tyson William R. , Gianetto James A. 
Published: August 2013

In ASTM standard E1820, the single edge bend (SE(B)) geometry is one of those recommended for fracture toughness testing. The width to thickness (W/B) ratio recommended in E1820 for this specimen is 2. However, in certain cases, it is desirable to use specimens having alternative W/B ratios; the range of W/B suggested in E1820 is 1 to 4. In E1820, the crack size a may be evaluated during J-integral or CTOD resistance testing using the crack mouth opening displacement (CMOD) elastic unloading compliance C. The equation given to relate a to C using a dimensionless compliance BCE incorporates Young’s modulus E. For the three-dimensional (3-D) SE(B) specimens that are in neither plane stress nor plane strain condition, this parameter E may be considered as a normalizing parameter varying between extremes E (plane stress) and E/(1−ν2) (plane strain) depending on crack depth (a/W) and specimen W/B ratio.
In the present study, 3-D finite element analysis (FEA) was used to evaluate the CMOD compliance of B×B SE(B) specimens with shallow and deep cracks and compared with that from Tada’s plane stress equation. Crack sizes evaluated using plane stress and plane strain assumptions with the 3-D CMOD compliance obtained from FEA were compared with the actual crack size of the specimens used in FEA. It was found that the errors in crack size using plane strain or plane stress assumptions can be larger than 5%, especially for shallow-cracked specimens. In the present study, an effective modulus with values between plane stress and plane strain is proposed and evaluated by FEA for the 3-D B×B SE(B) specimens. The values were fitted to a polynomial equation as a function of u = 1/(√(BCE)+1) for use in estimating the dimensionless compliance for crack size evaluation for B×B SE(B) specimens. It is shown that the errors in crack size evaluation can be significantly reduced using this effective modulus.
Predicting Post-Weld Residual Stresses in Ferritic Steel Weldments
Authors: Hamelin Cory J. , Muránsky Ondrej , Bendeich Philip J. , Edwards Lyndon 
Published: August 2013

The implementation of a semi-empirical solid-state phase transformation subroutine in the ABAQUS finite element package is presented to predict the influence of transformation strain on the post-weld residual stress field in ferritic steels. The phase transformation subroutine has been outlined in a previous study (PVP2011-57426), where it was proven accurate in predicting the phase compositions in the fusion and heat affected zone (HAZ) of an autogenous TIG beam weld in SA508 Gr.3 Cl.1 steel.
While previous work focused on predictions of the steady-state material response using a 2D thermal model, the present analyses are 3D and capture the varying phase composition at weld start- and stop-ends. Predicted cooling rates at either end of the specimen are significantly higher, leading to a variation in the predicted microstructure along the weld line.
To better understand the structural changes that occur in ferritic steels during a conventional welding process, a representative model of SA508 Gr.3 Cl.1 steel is discussed. The contribution of thermal, metallurgical, and transformation-induced plastic strain is highlighted in this example, providing insight to the key simulation variables necessary for accurate weld models of ferritic steels. Preliminary coupled thermo-mechanical analyses are presented that compare predicted residual stress distributions with those measured in SA508 Gr.3 Cl.1 beam welds via neutron diffraction; good agreement is observed.
Further Predictions of Fracture Experiments of a Pre-Cracked Pressurised Thermal Shock Disk (PTS-D) Specimen Under Warm Prestressing Loading Cycles
Authors: Teng H. , Sharples J. K. , Budden P. J. 
Published: August 2013

Finite element analyses have been performed to investigate the effects of warm prestressing (WPS) of a pre-cracked PTS-D (Pressurized Thermal Shock Disk) specimen. Three basic types of WPS loading cycles were used in the analyses: LUCF (Load-Unload-Cool-Fracture) cycle; LCF (Load-Cool-Fracture) cycle; and LCTF (Load-Cool-Transient-Fracture) cycle. The analyses aimed to predict the fracture toughness enhancements due to WPS using different analysis methods and to make comparisons with the experimental work conducted by the Belgium SCK-CEN organisation under the European NESC VII project.
The finite element results were used to derive the enhanced fracture toughness by three different engineering methods: (1) Chell’s displacement superposition method; (2) the local stress matching method; and (3) Wallin’s empirical formula. The enhanced fracture toughness was evaluated at the deepest point of the semi-elliptical crack based on three different levels of as-received fracture toughness of 43.96, 65.94, and 86.23 MPam1/2, which correspond to probabilities of failure of 5%, 50% and 95%, respectively.
The predicted fracture loads were compared with the experimental fracture loads for the three WPS loadings cycles. The results show good agreement.
Flow Loads on the Shroud in a Boiling Water Reactor due to a Recirculation Outlet Line Break: A Comparative Study Between Potential Flow and Computational Fluid Dynamics Methodologies
Authors: Ananth Raju , Sowah Sandra , Gillis Jay 
Published: August 2013

This paper compares two methodologies for estimating the flow loads on the shroud of a typical BWR caused by a Recirculation Outlet Line Break. First, assuming an ideal and irrotational flow field, the complex potential methodology is used to calculate a two dimensional approximation of the flow field by ignoring variations along the radial direction. As a simplification for the comparative study the annulus will be assumed to be devoid of any structural components such as the jet pumps. The flow field derived from the potential flow approach will be used to compute the total lateral and moment loads acting on the shroud. These load values will be compared against similar values derived from a three dimensional and more realistic flow field computed by Computational Fluid Dynamics (CFD).
The potential flow based method is computationally simpler as compared to the more time consuming CFD approach.
Scanning Electron Microscope of Fatigue and Creep-Fatigue From Stress Concentrations in Plates
Authors: Watanabe Osamu , Kikuchi Marina , Matsuda Akihiro 
Published: August 2013

Fatigue crack propagation forms a distinctive pattern which is observable on the fracture surfaces of materials. Purpose of this study is to analyze the fracture process of the materials received under cyclic distortion loading using scanning electron microscope. The test piece made of type 304 stainless steel with the hole of a different size is examined on the conditions of the high temperature fatigue and creep-fatigue. This study first takes a picture of the fracture with SEM, and measures the intervals of striation on fracture surfaces. Next, this study calculates the number of the crack propagation cycles and compares with the original experimental data defined by the load decrease condition or the crack length.
Consequently, there is not so much differences at striation intervals regardless of the size of the root notch radius in the present tests. However, the striation spacing in the creep fatigue test has grown about twice of striation intervals in the high temperature fatigue-test.
Study on the Frequency Response Characteristics of Thermal Stress Induced by Multidimensional Fluid Temperature Fluctuation
Authors: Perez T. Cristian Santiago , Kasahara Naoto 
Published: August 2013

A simplified one dimensional approach for predicting the thermal stress in structures subject to near wall fluid temperature fluctuations has been previously developed and published by the author Kasahara. The method predicted the thermal stress by calculating the frequency response, formulated by the product of the effective heat transfer and the effective thermal stress related to one-dimensional temperature gradient developed through the wall thickness of the structure. Although, currently adopted by the Japanese Society of Mechanical Engineers (JSME) guideline for calculating the thermal fatigue damage in structures, recent studies have highlighted the limitations of the one dimensional approach by showing the presences of multidimensional fluid temperature fluctuation in plane direction, increasing the need to extend the current analysis to more detailed multidimensional guideline.
The aim of this research is to advance the theoretical knowledge and understanding of complex multidimensional phenomenon related to local thermal fluctuations within small localized area at the surface of the structure, referred to as “Hot Spot” which is observed to have important effects on the thermal stress phenomenon. Furthermore, the understanding of heat transfer processes in the structure, especially heat diffusion that is known to produce a thermal gradient and, therefore, thermal stress. Understanding the behavior of each heat transfer process in the Hot Spot and the relationship to the response in frequency has formed the bases for extending the current one-dimensional model.
This paper presents the analytical results of the study and proposes an extended multidimensional model to understand the thermal stress in tee-junction due to fluid temperature fluctuation and the close relation with the frequency. The model is derived from the understanding of the phenomenon which has leaded to quantify the effect by introducing certain multidimensional factors to explain the impact of the multidimensional fluid temperature fluctuation.
Experimental Incompressible Forces Applied in a Safety Valve
Authors: Chabane Saïd , Corbin François , Couzinet Anthony , Pierrat Daniel , Bayart Martin 
Published: August 2013

Safety valves are crucial devices in the industry. Indeed, these valves are simple and robust in their design. Safety valves are the ultimate overpressure device protection when all other devices are insufficient or failed. The poor design of these devices can be disastrous.
A conventional safety relief valve is mainly composed of a disk maintained pressed against a nozzle by a spring. When the pressure forces on the upstream face of the disk are below the force applied to the spring, the valve is closed. If an accidental overpressure event occurs in the process under protection, the pressure forces become high compared to spring elastic forces and the safety valve opens to relief pressure. Thus, the pressure in the process under protection is reduced to an acceptable value.
The force exerted by the pressure on a disk of a safety valve is essential for a correct design of the spring and the inner ring. To understand the forces, a safety relief valve was modified and the spring removed; a force measurement tool was mounted in order to measure the forces exerted at different inlet pressure and lift. These tests were made for several ring settings.
These measurements were made in incompressible fluid on a water test loop.
Finally, inlet and outlet conditions of the safety valves were modeled respectively by thermodynamic 1D-model. The safety valve is described by dynamic 1D-model where the hydrodynamics forces applied to the moving disk are provided by measurements in water.
Dealing With Heavy Loads in Large Diameter Piping
Authors: Rojas Hector , Gutkovsky Andrey 
Published: August 2013

It is common in a refinery that some piping systems have to handle several flow conditions. However, when a new proposed condition implies the filling of an existing 68″ (1727 mm) line with molten Sulfur, which was initially designed for gas operation, a well thought engineering case study is required to guarantee that no damage will occur under the new operating conditions.
This paper covers the procedures employed to qualify the integrity of a 68″ (1727 mm) piping system, initially designed to carry Sulfur vapors and required to handle occasional filling with molten Sulfur due to operational demands.
The procedures of reviewing the initial configuration, design of modifications and reinforcements to the piping system and the use of Finite Element Analysis (FEA) in order to qualify several unique support configurations are explained in this paper.
Alternative Tracing Gas Mixtures for Valve Fugitive Emission Measurements
Authors: Lejeune Hubert , Cougnon Laurent 
Published: August 2013

Helium is commonly used as a tracer gas for leakage measurements across the world. This gas is easy to use without safety issues and enables to measure a very wide magnitude of leakage rates with well proven detectors (Mass Spectrometers). Nevertheless, shortage and price increase of helium in several world areas, encourage industry users to look for alternative tracing gases for leakage measurement.
The Valve Commission of CETIM has decided to investigate the use of two alternative tracer gas mixtures in the field of packing fugitive emissions testing according to ISO 15848-1. This standard allows the use of Helium and Methane as tracer gases. The leakage measurements based on Hydrogen tracer gas has been developed in the recent years, with the use of Hydrogen (5%)-Nitrogen (95%) mixture for safety concerns.
The test programme involves comparative fugitive emission measurements on graphite packing, following ISO 15848-1 test procedure with Helium, Hydrogen (5%)-Nitrogen (95%) and Methane (10%)-Nitrogen (90%) mix tracer gases. Several measuring methods are investigated as sniffing, accumulation, flushing and global vacuum using the relevant detectors for the different gases and measurement methods.
Whereas the measurements did not appear to be sensitive enough with the Methane (10%)-Nitrogen (90%) for some measurements methods, the Hydrogen (5%)-Nitrogen (95%) mixture has shown a good potential for fugitive emission measurements according to ISO 15848-1.
Cleavage Crack Propagation and Arrest in a Nuclear Pressure Vessel Steel
Authors: Bousquet Amaury , Marie Stéphane , Bompard Philippe 
Published: August 2013

The integrity assessment of Reactor Pressure Vessels, mainly based on crack initiation, can be completed by studying crack propagation and arrest. Whereas engineering approaches do not take into account dynamic effects, these effects are important in unstable cleavage crack propagation, arrest and possible propagation re-initiation events. This study deals with physical mechanisms of cleavage crack propagation and numerical computations related to brittle fracture in the framework of local approach to fracture.
Experiments were carried out on thin CT 25 specimens made of 16MND5 PWR vessel steel at five temperatures (−150°C, −125°C, −100°C, −75°C, −50°C). Two kinds of crack path, straight or branching path, were observed. Branching cracks appear for the highest critical loadings at initiation, that increase the elastic stored energy and the effect of plasticity. The elastic-viscoplastic behavior of the ferritic steel was studied up to a strain rate of 104 s−1 and taken into account in the numerical simulations. The eXtended Finite Element Method (X-FEM) was used in CAST3M FE software to model crack propagation. Numerical computations combine a local non linear dynamic approach with a RKR type fracture stress criterion. The different physical micro-mechanisms, involved in cleavage fracture, were examined by the means of SEM fracture surface analyses at different temperatures and strain rates for the two kinds of crack path.
The links of the critical fracture stress with both temperature and strain rate for straight crack path as well as analyses of branching crack phenomena were considered by the means of Scanning Electron Microscopy (SEM) fracture surface analyses, 3D quantitative optical microscopy and FE computations in order to aim at a robust physical justification of the propagation model which has already been developed at CEA in the frame of the B. Prabel PhD.
Study on Collapse Characteristics and CSRF Method for 45 Deg Cylinder-to-Cylinder Intersections
Authors: Honda Takuro , Kataoka Shunji , Sato Takuya 
Published: August 2013

It is known that the collapse strength of complex three dimensional structures is hard to evaluate accurately with elastic analysis, and more accurate results require the use of inelastic analysis. A cylinder-to-cylinder acute lateral intersection is one of basic structures of process plants. It is known that a high stress concentration occurs at an acute lateral more than 90 deg-lateral. In general, the area replacement method and the elastic analysis are applied for the design of acute lateral. However, these results may provide overly-conservative designs.
In the previous work, the authors proposed CSRF (Collapse Strength Reduction Factor) method. The CSRF was defined as a ratio of the simple cylinder collapse pressure to the cylinder-to-cylinder collapse pressure. The proposed CSRF method provided more reasonable design than the elastic analysis.
In this paper, the concept of the CSRF was redefined by using the maximum allowable working pressure. The CSRF were evaluated on the 45 deg and 90 deg-laterals based on the area replacement method, the elastic analysis, the limit load analysis and the elastic plastic analysis to study the collapse characteristics of 45 deg-laterals. The 45 deg-laterals are weaker than 90 deg-laterals, and inelastic analysis provides greater strength of 45 deg-laterals than elastic analysis. The results of elastic plastic analysis showed that overly-large plastic strain occurs on 45 deg-laterals. This plastic strain should be evaluated in addition to the collapse pressure.