bluuebunny/crossref_metadata_2025_split huggingface dataset:
Relevance of UV filter/sunscreen product photostability to human safety
Authors: Nash J. Frank , Tanner Paul R. 
Published: January 2014

SummaryPhotostability or photo‐instability of sunscreen products is most often discussed in undesirable terms with respect to human safety. The health risks, specifically associated with sunscreens, photostable or photo‐unstable, include phototoxic/photoirritation or photoallergic responses and, longer‐term, an increased risk of skin cancers or photoageing. The aims of this paper are to define photostability/photo‐instability and objectively assess the acute and chronic toxicological consequences from the human exposure to UV filter/sunscreens and any probable photo‐degradation products. The reported prevalence of photoirritation and photoallergic responses to sunscreens is rare compared with adverse events, for example, skin irritation or sensitization, produced by cosmetics or topically applied drugs and do not directly implicate potential photo‐degradation products of UV filters. Moreover, for at least one photo‐unstable combination, octyl methoxycinnamate and avobenzone, the long‐term benefits to humans, i.e., reduction in skin cancers, seem to outweigh any potential adverse consequences attributed to photo‐degradation. Sunscreen products are formulated to achieve maximum efficacy which, by necessity and design, incorporate measures to support and promote photostability since all organic UV filters have the potential to photo‐degrade. Current performance measures, in vivo SPF and in vitro UVA, conducted under standardized conditions, in part account for photostability. The concerns expressed when considering human exposure to potential photo‐unstable UV filters or sunscreen products may not manifest as health risks under conditions of use. Still, improvement in sunscreen product photostability continues to be a key strategic objective for manufacturers.
Analysing the Notch Effect Within the Ductile-to-Brittle Transition Zone of S275JR Steel
Authors: Cicero Sergio , García Tiberio , Madrazo Virginia , Cuervo Jorge , Ruiz Estela , Gutiérrez-Solana Federico 
Published: January 2014

This paper analyses the notch effect in ferritic-pearlitic steel S275JR in a range of temperatures within the material Ductile-to-Brittle Transition Zone (DBTZ). The notch effect is evaluated in terms of load-bearing capacity, apparent fracture toughness (modeled here using the Theory of Critical Distances) and fracture micromechanisms. The concept of Master Curve in notched conditions is also presented.
To this end, experimental results obtained in S275JR notched specimens are presented, together with Scanning Electron Microscopy (SEM) fractographies. The analysis is performed at −50 °C, −30 °C and −10 °C, the material Transition Temperature (T0) being −26.1 °C, with the notch radii ranging from 0 mm (crack-type defects) up to 2.0 mm.
The results show how the lower the temperature the larger the notch effect, and also that the evolution of both the load bearing capacity and the apparent fracture toughness is directly related to the evolution of fracture micromechanisms. Moreover, the proposed Master Curve in notched conditions has provided good predictions of the experimental results.
Consideration of Design Assessments for Pipeline/Facilities Dynamic Behavior
Authors: Motriuk Roman W. 
Published: January 2014

Information of PTQ (pressure, temperature, flow) in hydrocarbon transmission pipelines or facilities is critical because modeling of such systems, or their parts, involves fluid transport-properties that critically influence any fluid-pipe and soil-pipe interactions. These properties across soil varieties are integral to predicting pipeline systems’ behavior.
The mechanical/fluid aspect of analysis is reviewed in this work, with emphasis on steady-state and transient system responses. In general terms, the necessary steps of dynamic analysis used at the design stage of pipelines and facilities are described. Comments on sources of excitation and the response of pipe/pipelines, which take into account transient and steady-state system behavior, as well as the importance of using accurate fluid transport properties are discussed.
Evaluation of Mechanical Properties of Primary Circuit Components Using SPT Technique
Authors: Březina Martin , Petzová Jana , Kupča Ľudovít 
Published: January 2014

The paper deals with the evaluation of mechanical properties of safety-related components of the primary circuit of nuclear power plants (NPPs). During a long-term operation of NPPs, changes of mechanical properties occur. To ensure the safe operation of NPP it is necessary to monitor and evaluate these changes. One possibility how to solve this problem is a direct sampling and the assessment of the actual mechanical properties using the small punch test (SPT) technique. By the SPT technique it is possible to evaluate the basic tensile properties such as the ultimate tensile strength and the yield stress of the tested materials as well as the transition temperature.
The authors describe model examples of surface sampling using the special Rolls Royce equipment SSam™-2. The SPT specimens were prepared from the removed samples by application of the wire electrical discharge machining and fine grinding. The prepared specimens were tested and the obtained data were evaluated. Original pieces of primary tubes with diameter 500 mm made of stainless steel type 08Ch18N10T (AISI 321) were used for these model examples. Another experimental material used was a block of the reactor pressure vessel wall cut from NPP Greifswald Unit 7 which contains a weld joint. Those experiments were a part of the preparatory activities for the planned sampling and the assessment of the actual mechanical properties of primary components such as the main primary coolant piping, the steam generator shell and the reactor pressure vessel.
Cleavage Fracture Modelling for RPV Steels: Discrete Model for Collective Behaviour of Micro-Cracks
Authors: Abu-Muharib Andrew , Jivkov Andrey P. , James Peter , Yates John R. 
Published: January 2014

The ability to predict variations in cleavage fracture toughness behaviour of ferritic RPV steels, accounting for the effects of irradiation and defect geometry, is vital to safety assessment and life extension decisions. Local approaches to cleavage fracture offer a promising methodology to accomplish such calculations. However, the limited progress achieved by improving the local failure probability expression suggests that the methodology for calculating global cleavage might not be adequately representing real material. The basis for the existing methodology is the weakest-link assumption that all individual failure events are independent and non-interacting. Here an approach is considered which utilises a microstructure-informed model incorporating the experimental knowledge needed to postulate deterministic criteria for particle rupture and micro-crack propagation, whilst accounting for the probabilistic distribution of particle sizes. This is then used in a lattice model that can help detail the evolution of the formation of micro-cracks on global failure, therefore inferring the suitability of the weakest-link assumption. Predicting the probability of cleavage fracture requires such models, as the macroscopic cleavage phenomenon is governed by a number of micro-structural features.
The material microstructure is represented by a regular lattice of truncated octahedral cells forming a computational site-bond model, with sites located at the cell centres and connected by two distinct sets of bonds. These bonds are modelled with structural beam elements, which represent all the possible relative deformations between coordinated sites. Particles of various sizes are distributed in the bonds, based on an experimentally determined distribution of cleavage initiating particles in RPV steel (Euro Material A). Although only elastic deformations are considered here, the results demonstrate that the interactions between individual failure events could potentially have a strong effect on the way global failure is reached.
Nucleation of micro-cracks by rupturing second-phase particles affects their subsequent formation. In particular, it was found that once formed there is a reduced probability of further development of micro-cracks at particles outside the crack planes and an enhanced probability of formation at particles along the crack planes. This will therefore influence the distribution of micro-crack sizes that could in principle be used to calculate the global probability of failure, and could lead to substantially different distributions of particle sizes, then used in the current local approach methods.
Detail Investigation of Omega Method for Creep Analysis of Pressure Vessel Components
Authors: Vivio Francesco , Gaetani Luca , Ferracci Michele , Masia Alessandro 
Published: January 2014

A comprehensive creep material model for evaluation of high temperature applications of ferritic, martensitic and austenitic steels is available in API 579-1/ASME FFS and in ASME VIII Div 2 CC-2605-1 codes based on MPC Project Omega.
Although the model can be used directly to analyze pressure vessels components behavior in a non-linear finite element creep analysis, several numerical and theoretical limits are to be taken into account in the implementation of the FE user-subroutine of the material model.
In this context, a deep parametric analysis, both theoretical and numerical, based on different possible operating conditions and material behavior (temperature, pressure, stress field, elastic-plastic material properties and plastic flow rules) has been performed to review the model results on a high pressure vessel component.
Based on results of these analyses, a theoretical critical review of the method is presented.
Experiments to Determine the Influence of Residual Stress and Elastic Follow-Up on Creep Crack Initiation
Authors: Shirahatti A. M. , Truman C. E. , Smith D. J. 
Published: January 2014

Components used in the power generation sector are often continuously exposed to high temperatures and corrosive environments. Failure processes, such as net section rupture, creep crack growth or fatigue crack growth therefore occur within the high temperature regime. The presence of residual stresses plays an important role in the subsequent failure of engineering components and structures. Residual stresses can arise from almost all manufacturing and fabrication processes and can also arise during service. Tensile residual stresses may combine with in-service loads to promote failure at a load the designer would view as safe. A quantitative understanding of how residual stresses interact with applied service loads is thus required for accurate safety assessments.
In this paper a test rig based on a three bar structural model is used to introduce long range residual stresses in a 316H steel C(T) specimen at high temperature. The residual stresses induced are characterized easily without use of time consuming residual stress measurement techniques. The complete test rig is then subjected to an applied load. The magnitude of the residual and applied stress in the 316H C(T) specimen is a function of the initial misfit displacement, applied load and relative stiffness of the components of the test rig. The experimental results show that a test rig with a higher elastic follow-up value will have more crack growth compared to a rig with a lower elastic follow-up. Also, both tests demonstrate that as the crack grows, relaxation of residual stress in the C(T) specimen occurs, and it is compensated by a change in residual stress distribution in other parts of the rig. Furthermore, creep crack initiation data is compared with load controlled tests conducted. It is found that the time for the crack to initiate is increased in the case of mixed boundary conditions compared to load controlled conditions.
The Effect of Different Types of Surface Preparation on Lap Shear Strength of a Typical Ambient Cured Carbon Fiber Composite Repair System
Authors: Mally Timothy S. , Keller Michael W. , Walker Roger H. 
Published: January 2014

A crucial factor in a composite repair installation is the degree of surface preparation that is available. The surface profile that is created is directly proportional to the bond strength of the composite repair to the substrate. A NACE-2 near-white metal sandblast is ideal surface preparation for a composite repair. However, this degree of surface preparation is not available for every installation for various reasons. As a result, this paper details the effects of several different kinds of surface preparation on composite bond strength.
Details are presented for the lap shear testing of a carbon fiber reinforced polymer (CFRP) according to ASTM D5868. Five different surface preparation techniques are tested, including NACE-2 sandblast, bristle blast, wire brush, carbide grinder, and sand paper. The testing is used to calculate the necessary degree of surface preparation required to sustain an acceptable field repair.
Test samples are fabricated according to the ASTM standard, and are tensile tested on an MTI-5K tensile machine. The lap shear values are compared to acceptable values required in the ASME Post Construction Code 2. Industry experience is also considered as it is determined whether these surface preparation methods are acceptable for in-situ composite repair.
Comparison of R5 and ASME NH Creep-Fatigue Damage Assessment Methodologies
Authors: Sheridan Michael , Knowles David , Montgomery Oliver 
Published: January 2014

The R5 volume 2/3 procedures [1] were developed by British Energy (now EDF Energy) to assess the high temperature response of uncracked metallic structures under steady state or cyclic loading. They contain the basic principles of:
• Application of reference stress methods
• Consideration of elastic follow up
• A ductility exhaustion approach to calculate creep damage accumulation.
These considerations represent a fundamental distinction from ASME BPVC Section III, Subsection NH [2].
This paper draws on literature review and experience to explain the principal differences in the limits of application, cycle construction and damage calculation between these codes/procedures focusing on creep-fatigue damage determination. The implications of the differences between the codes and standards are explored.
The output of this work is aimed at two groups of structural integrity engineers; those using these codes and standards to assess existing conventional and nuclear plant, and also those looking to ASME and R5 to design Generation IV PWRs with design temperatures much elevated from those of Generation III and III+.
The conclusions from this paper offer some practical guidance to structural integrity engineers which may assist in selecting the more appropriate procedure to assess creep-fatigue damage for a particular situation.
A Design Approach Based on Historical Test Data and Bayesian Statistics
Authors: Wei Zhigang , Yang Fulun , Konson Dmitri , Nikbin Kamran 
Published: January 2014

Testing is still the final verification for a design even though there are substantial number of analytical and simulation methods available. Testing is seen to be also an indispensable part in the foreseeable future. Numerous test data have been generated in many testing institutions over the years and it is clear that future new tests will be conducted. Historical data with similar design and operating conditions can shed light on the current and future designs since they would share some common features when the changes are not dramatic. To effectively utilize the historical data for future design, two steps are necessary: (1) finding an approach to consistently correlate test data obtained from various conditions; (2) Use of Bayesian statistics which can provide a rational mathematical tool for extracting useful information from the historical data.
In this paper, the basic Bayesian statistical procedure based on the historical data is outlined. With this information the reduction of sample size number or improving the accuracy and confidence with the same sample size are becoming possible. Examples of utilizing the historical data are also presented and the benefit of using the Bayesian statistics are highlighted.
Influence of Phase Transformations on Residual Stresses in Welded Structures
Authors: Dennis R. J. , Kulka R. , Muransky O. , Smith M. C. 
Published: January 2014

A key aspect of any numerical simulation to predict welding induced residual stresses is the development and application of an appropriate material model. Often significant effort is expended characterising the thermal, physical and hardening properties including complex phenomena such as high temperature annealing. Consideration of these aspects is sufficient to produce a realistic prediction for austenitic steels, however ferritic steels are susceptible to solid state phase transformations when heated to high temperatures. On cooling a reverse transformation occurs, with an associated volume change at the isothermal transformation temperature.
Although numerical models exist (e.g. Leblond) to predict the evolution of the metallurgical phases, accounting for volumetric changes, it remains a matter of debate as to the magnitude of the impact of phase transformations on residual stresses. Often phase transformations are neglected entirely. In this work a simple phase transformation model is applied to a range of welded structures with the specific aim of assessing the impact, or otherwise, of phase transformations on the magnitude and distribution of predicted residual stresses. The welded structures considered account for a range of geometries from a simple ferritic beam specimen to a thick section multi-pass weld. The outcome of this work is an improved understanding of the role of phase transformation on residual stresses and an appreciation of the circumstances in which it should be considered.
Determination of the Transition Temperature Scatter Using the Charpy Data Scatter
Authors: Orynyak Igor , Zarazovskii Maksym , Bogdan Andrii 
Published: January 2014

For a pressure vessels integrity assessment it is necessary to know the transition temperature of metal. It is defined from the hyperbolic tangent curve, which best approximates the Charpy V-notched (CVN) impact tests data, as the temperature corresponding to some fixed Charpy impact energy.
However, when planning experiments, processing of the results, and interpreting of the resulting transition temperature, two problems arise which have not been studied in the literature. First — sufficiency of the CVN impact tests data for a curve fit building and transition temperature determination. Second — experimental data scatter accounting while determining the transition temperature.
This work proposes to define two quantitative characteristics: the “importance” of each CVN impact test for the defined transition temperature; the transition temperature scatter which is calculated from the Charpy impact energy data scatter with consideration of the above “importance”. Also the data points sufficiency criterion for adequate defining the transition temperature is formulated.
Numerical experiments carried out on sets of test data have shown a good correlation between transition temperatures scatter calculated by the standard method and by the one developed in the present paper. Analysis of RPV weld metal surveillance data in the initial and irradiated conditions for Unit 1 and 2 of South-Ukrainian NPP shows that the transition temperature scatter, determined in this way, reaches 26°C.
Deflection of Gaskets and its Effect on Tightness of Flanged Connections in Long Term
Authors: Kobayashi Takashi , Nishiura Kengou , Hiratsuka Masaaki , Itoi Katsutoyo 
Published: January 2014

The deflections of gaskets after initial tightening largely affect the residual bolt forces and the tightness of bolted flanged connections. The bolt forces decrease significantly due to the deflections of gaskets after initial tightening in the cases where PTFE gaskets are used. The visco-elastic characteristic of gaskets is the main cause for the phenomenon. It has been shown that the tightness improved even if the bolt forces reduced in the long term. The reason was thought that gaskets became packed under a high gasket stress. Because of this effect, the leak rate decreased. It is important to estimate the thickness change of gaskets to evaluate the tightness of flanged connections.
In this paper, a model of a flanged connection, in which the flange, the bolts and the gasket are represented by spring constants, is proposed. Using the model, the relationship between the gasket deflection and the tightness are discussed.
Use of the Alternating Current Potential Drop (ACPD) Technique to Monitor Creep Behaviour of Austenitic Steels
Authors: Narayanan Aditya , Davies Catrin M. , Mahmoud Yasser K. 
Published: January 2014

The Alternating Current Potential Drop (ACPD) strain sensor has been developed as a tool to monitor the condition of a material. It is comprised of a square array of sensors that measures the resistance in two orthogonal directions, using the changes in the material’s resistance over time as a measure of its deformation and evolution of damage within it due to creep. The method expresses the change in resistance as the ratio of axial to lateral resistance, suppressing temperature-related effects on material resistivity, which are mostly isotropic.
Previous experiments have seen this method applied to samples of ferritic (2.25CrMoV) steel at 650°C [1]. Within this paper, the method has been extended to include work on the austenitic stainless steel 316H (17Cr11NiMo). Results of a series of interrupted creep tests are presented that show the resistance behaviour of the material at different points in its creep life. Metallographic studies have also been performed so as to establish how data gained using this technique is related to the condition of the material.
Study on Validity of Stress Intensity Factor in CT Specimen for Materials With Low Yield Stress
Authors: Takanashi Masahiro , Itabashi Yu , Hirano Takashi 
Published: January 2014

This paper discusses the validity of a stress intensity factor K for compact tension (CT) specimens of stainless and low-alloy steels by computing J-integral values. In fracture mechanics testing, specimen configurations and loading conditions are strictly regulated to meet the small-scale yielding (SSY) condition and obtain valid data. For some materials, particularly those without an obvious yield point, it is hard to meet the SSY condition. The regulations specified in fracture mechanics test standards are based on experimental results. The theoretical reason for the SSY condition is not necessarily clear and the condition seems conservative.
This study focuses on a correlation with the stress intensity factors K and the J-integral values under the SSY condition. J-integral values of CT specimens were analyzed by elasto-plastic finite element analysis. Subsequently, the validity of the stress intensity factor K was checked by comparing K and J–integral values to determine whether CT specimens were under the SSY condition or not. To simplify the comparison, J-integral values were converted to K values, equivalent stress intensity factor KJ values.
When K values were low enough to meet the SYY condition of the specimen, they equaled KJ values. Meanwhile, KJ values exceed K values in a high K region, which means the specimen is no longer under a SSY condition. It is possible to determine whether the specimen is under the SSY condition or not by comparing the values of KJ and K. This paper evaluated the validity of K values using the correlative relationship and showed that they were valid to some extent even if loading conditions and specimen configurations were outside the scope of the specification by the test standards. The validity of K values with 0.2% offset strength or flow strength instead of yield stress is also confirmed by this method.