bluuebunny/crossref_metadata_2025_split huggingface dataset:
An extinct, Late Mesoproterozoic, Sveconorwegian mantle wedge beneath SW Fennoscandia, reflected in seismic tomography and assessed by thermal modelling
Authors: Slagstad Trond , Maystrenko Yuriy , Maupin Valerie , Gradmann Sofie 
Published: October 2017

AbstractA channel‐like, low‐velocity zone in the lithospheric mantle beneath W Norway coincides spatially with the extension of a recently discovered 200 × 50 km granite batholith, which formed as a result of oceanic subduction beneath the SW Fennoscandian margin between 1.07 and 1.01 Ga. Based on results from numerical modelling, we argue that the low‐velocity zone, at least in part, reflects the thermal (radioactive) effects of the refertilized mantle wedge of this magmatic arc. The geological record in SW Fennoscandia suggests that active‐margin magmatism terminated as a result of rapid slab rollback and trench retreat starting at ca. 1 Ga. The rapid shift from active‐ to passive‐margin processes was probably critical in preserving the mantle wedge, and its identification can therefore shed light on how active‐margin processes terminated in ancient orogens.
The effect of sex and prematurity on the cardiovascular baroreflex response in sheep
Authors: Allison Beth J. , Nguyen Vivian , Yiallourou Stephanie R. , Nitsos Ilias , Black Mary Jane , Polglase Graeme R. 
Published: October 2017

New Findings
What is the central question of this study?
Late preterm infants are often assumed to escape long‐term morbidities known to impact earlier preterm offspring. Is this true for the cardiovascular system?

What is the main finding and its importance?
We show that late preterm birth is a risk factor for cardiovascular dysfunction in early adulthood and is influenced by sex. Early signs of cardiovascular dysfunction might predispose to heart disease in adulthood.

Very preterm infants have an increased risk of cardiovascular disease; however, the effects of a late preterm birth on future cardiovascular function are not known. We hypothesized that after a late preterm birth, the well‐described impairments in heart rate variability and baroreflex sensitivity would persist into adulthood. To test this hypothesis, sheep born preterm (0.9 gestation; nine male and seven female) or term (11 male and six female) underwent surgery at 14 months of age for insertion of femoral arterial and venous catheters and a femoral flow probe. After recovery, heart rate variability was assessed, followed by a baroreflex challenge (using the vasoactive agents phenylephrine and sodium nitroprusside) in conscious adult lambs. Our data demonstrate decreased low‐frequency normalised units (LFnu) and low‐frequency/high‐frequency ratio in female but not male ex‐preterm sheep at rest. When challenged, mature male ex‐preterm sheep have an increased blood pressure response but dampened heart rate baroreflex response. We show that even a late preterm birth leads to cardiovascular dysfunction in adulthood. These early signs of cardiovascular dysfunction might underpin the later hypertension and increased risk of heart disease observed in adults born preterm. These findings are particularly important because late preterm infants are often assumed to escape the long‐term morbidities known to impact on very preterm and extremely preterm offspring.
Axonal GABAA receptors depolarize presynaptic terminals and facilitate transmitter release in cerebellar Purkinje cells
Authors: Zorrilla de San Martin Javier , Trigo Federico F. , Kawaguchi Shin‐ya 
Published: October 2017

Key points
GABAA receptors have been described in the axonal compartment of neurons; contrary to dendritic GABAA receptors, axonal GABAA receptors usually induce depolarizing responses.
In this study we describe the presence of functional axonal GABAA receptors in cerebellar Purkinje cells by using a combination of direct patch‐clamp recordings from the axon terminals and laser GABA photolysis.
In Purkinje cells, axonal GABAA receptors are depolarizing and induce an increase in neurotransmitter release that results in a change of short‐term synaptic plasticity.
These results contribute to our understanding of the cellular mechanisms of action of axonal GABAA receptors and highlight the importance of the presynaptic compartment in neuronal computation.
AbstractIn neurons of the adult brain, somatodendritic GABAA receptors (GABAARs) mediate fast synaptic inhibition and play a crucial role in synaptic integration. GABAARs are not only present in the somatodendritic compartment, but also in the axonal compartment where they modulate action potential (AP) propagation and transmitter release. Although presynaptic GABAARs have been reported in various brain regions, their mechanisms of action and physiological roles remain obscure, particularly at GABAergic boutons. Here, using a combination of direct whole‐bouton or perforated patch‐clamp recordings and local GABA photolysis in single axonal varicosities of cerebellar Purkinje cells, we investigate the subcellular localization and functional role of axonal GABAARs both in primary cultures and acute slices. Our results indicate that presynaptic terminals of PCs carry GABAARs that behave as auto‐receptors; their activation leads to a depolarization of the terminal membrane after an AP due to the relatively high cytoplasmic Cl− concentration in the axon, but they do not modulate the AP itself. Paired recordings from different terminals of the same axon show that the GABAAR‐mediated local depolarizations propagate substantially to neighbouring varicosities. Finally, the depolarization mediated by presynaptic GABAAR activation augmented Ca2+ influx and transmitter release, resulting in a marked effect on short‐term plasticity. Altogether, our results reveal a mechanism by which presynaptic GABAARs influence neuronal computation.
Gaseous Deflagration in Piping: Part 2 — Proposed Methods and Code Acceptance Criteria
Authors: Minichiello John C. , Ligon Thomas C. , Gross David J. 
Published: October 2017

This paper proposes Piping Code rules to address the effects of hydrogen deflagrations inside piping. Previous work proposed a set of criteria for piping subject to detonation loading [PVP2012-78519, PVP2012-78525]. This paper provides criteria to evaluate the effect of deflagrations, which typically have a slower rise time and lower energy, inside the piping. These deflagration criteria, coupled with the previously cited detonation criteria, are being used at the Hanford Tank Waste Treatment and Immobilization Plant to evaluate piping systems subject to hydrogen accumulation.
The previous papers did not investigate or propose criteria for deflagrations, as these were known to have lower pressures and slower pressure rise times, but are still of some significance for piping design. Recent work has shown that there exists a scenario in which the deflagration loading may be very significant: deflagrations in small gas pockets surrounded by large waste slugs. Depending on the assumptions used to develop the loading, the unbalanced forces on piping segments in a long piping system can become high during a deflagration event. Thus, for the set of criteria chosen for deflagration, the deflagration event may become the limiting event, especially if it is the more frequent event. The criteria proposed need to recognize this scenario and guide the user to possible solutions. This paper presents the original methodology for evaluating these “slug” events, briefly discusses the recent testing and theory being pursued to reduce the effect of the loading [PVP2015-45970, PVP2016-63260, PVP2016-63262], and then proposes criteria for evaluating deflagration induced stresses and loads.
Correlation of Fractographic Examinations With Numerical Calculations Regarding Dynamic Fracture
Authors: Tlatlik Johannes , Reichert Thomas 
Published: October 2017

In practice, cleavage fracture assessment for ferritic reactor pressure vessel steels is standardized by the quasi-static Master Curve concept (ASTM E 1921) on a macroscopic level. This standard is technically valid for dynamic loading conditions, yet recent work has shown that experimentally determined fracture toughness values under rapid loading lead to discrepancies regarding the shape of the Master Curve. It is assumed that one reason for these discrepancies is the profound adiabatic heating. The investigation of this, as well as related phenomena, is subject of this work.
Regarding this work, these experimental discrepancies are specified by a wide range of experiments. Moreover, fractographic investigations were performed on this experimental database to determine the exact origin of cleavage fracture, and compared to data from quasi-static experiments. In a second step numerical simulations were conducted for various crack-tip loading rates and testing temperatures, whereupon the temperature development in the cleavage fracture relevant region was quantified. This also allowed a determination of the individual initiation temperatures, which were analyzed and discussed whilst also taking into account the increase in local strain rate at the origin of cleavage fracture.
Finally, fractographic examinations also revealed the relevance of local crack arrest (crack stop) which was quantified, and also linked to the mentioned experimental discrepancies regarding the Master Curve concept.
Vibration Testing of Compression Joints
Authors: Hirschberg Paul , Sindelar Mark , Kassar Maher , Haupt Ron 
Published: October 2017

The use of compression joints in ASME Nuclear Class 2 and 3 small diameter piping systems has become increasingly popular because their installation does not require welding, and therefore saves time, money, and radiation dose. An important question is whether these types of joints can be a practical alternative to socket welds in piping systems subject to vibration. There have been numerous operating experience events where socket welds have developed cracks due to high cycle fatigue. On the other hand, parts of compression joints plastically deform the pipe to grip and create their sealing connection; the application of a high cycle vibration load to an already plastically strained pipe might lead to premature failure. It is desired to know whether at least one type of compression joint would perform better or worse than socket welds in such an environment.
In this paper, a testing methodology is described, in which one supplier’s coupling joint design was tested for vibration loading in tubing assemblies of varying sizes. The intended application for these joints is in an Electro-Hydraulic Control system at a northeastern Boiling Water Reactor plant. Industry experience reports have identified past vibration problems in this system at other plants. A test setup was devised, in which multiple specimens could be tested simultaneously by adjusting specimen natural frequency, shake table speed, and input acceleration. Fatigue Strength Reduction Factors were derived, allowing the resistance to fatigue failure to be quantified. Both compression joints and socket welds were tested using the same procedures, in order that the fatigue damage resistance could be compared between the two types of joints.
Effect of Material Anisotropy on the Structural Integrity of Composite Bolted Flanged Joints
Authors: K. Vafadar Ali , Bouzid Abdel-Hakim , Ngô Anh Dung 
Published: October 2017

The leakage tightness and structural integrity are the two most important criteria that are considered in the design of bolted flanged joints; composite flanges are no exception. Although the current practice is to use existing design methods for metallic flanges in the design of FRP flanges, their ability to appropriately address the anisotropic behavior of composite flanges is of major concern. Several failures of such flanges has fostered new alternative to design composite flanges.
This paper assess the reliability of numerical modeling of FRP bolted joints based on isotropy and compares the results with anisotropic based numerical Finite Element (FE) modeling. Experimental data are included to support the findings and emphasis the importance of including anisotropy to predict stresses and strains in composite flanges.
Optimizing Maintenance Strategy of a Reactor Pressure Vessel Using 3D-CFD and FEM Based Probabilistic Pressurized Thermal Shock Analysis
Authors: Ruan Xiaoyong , Nakasuji Toshiki , Morishita Kazunori 
Published: October 2017

The structural integrity of a reactor pressure vessel (RPV) is important for the safety of a nuclear power plant. When the emergency core cooling system (ECCS) is operated and the coolant water is injected into the RPV due to a loss-of-coolant accident (LOCA), the pressurized thermal shock (PTS) loading takes place. With the neutron irradiation, PTS loading may lead a RPV to fracture. Therefore, it is necessary to evaluate the performance of RPV during PTS loading to keep the reactor safety.
In the present study, optimization of RPV maintenance is considered, where two different attempts are made to investigate the RPV integrity during PTS loading by employing the deterministic and probabilistic methodologies. For the deterministic integrity evaluation, 3D-CFD and finite element method (FEM) simulations are performed, and stress intensity factors (SIFs) are obtained as a function of crack position inside the RPV. As to the probabilistic integrity evaluation, on the other hand, a more accurate spatial distribution of SIF on the RPV is calculated. By comparing the distribution thus obtained with the fracture toughness included as a part of the master curve, the dependence of fracture probabilities on the position inside the RPV is obtained. Using the spatial distribution of fracture probabilities in RPV, the priority of the inspection and maintenance is finally discussed.
Finite Element Analysis Based Stress Intensification Factor Calculation and Comparison With Various Approaches for Stress Intensification Factor Calculation
Authors: Kulkarni Mahesh , Dewangan Vivek 
Published: October 2017

Piping caters a major role in the process industries wherein stress intensification factor (SIF) express the Piping flexibility of the system. A typical Piping system consists of combination of pipes and various fittings with intersection geometries namely bend, tee, reducer, etc. A SIF is a multiplier on nominal bending stress so that the effect of geometry and welding can be considered in a flexibility analysis. An attempt has been made to compare the SIF values among ASME Piping B31.3, Welded Research Council (WRC) Bulletin 329, Paulin Research Group (PRG) empirical data and shell-based finite element analysis (FEA) for various tee sections based on in-plane and out-plane bending moments through this paper. The bending moment which causes tee to open/close in the plane formed by two limbs of tee is called in-plane bending moment. The bending moment which causes branch of tee to displace out of the plane retaining run pipe steady is called Out-plane bending moment.
ASME B31.3 provide guidelines to evaluate SIF values through empirical formulation as per Appendix-D with few limitations listed below.
1. Valid for d/D < 0.5 only
2. Non-conservative for 0.5 < d/D < 1.0
3. Valid for D/T ≤ 100
4. SIF values calculated with respect to header pipe. There is no difference in SIF values for header and branch pipe and it is the average value.
WRC 329 was published in 1987 and has not been updated taking ASME B31.3 latest edition into account. PRG carried out SIF for the various sizes and types of tee fittings and prepared correlation equations through detailed FEA using nonlinear regression and test data.
Dynamics Modeling and Analysis of Riveted Mainframe Computer Structure
Authors: Notohardjono Budy , Ecker Richard , Canfield Shawn 
Published: October 2017

A typical mainframe computer rack is narrow, tall and long. In certain installations, during its functional operation, the server can be subjected to earthquake events. The rack is a steel structure joined together with steel rivets. One of the rack’s functions is to protect the critical components such as the processor, input-output and storage drawers from excessive motion by minimizing the amount of deflection. The riveted joints pose a challenge in accurately representing more than three thousand joints in a finite element (FE) model. In the FE model, bonding together sheet metal regions around the rivet joints will lead to a significantly stiffer model than the actual structure. On the other hand, an accurate representation of the riveted joints will lead to a better representation of the dynamic response of the server rack under vertical and horizontal loadings.
This paper presents a method of analyzing rivet joints. The rivet joints are represented by beam elements with cylindrical cross-sections in the FE model. This is accomplished by identifying two parallel or overlapping plates and inserting discrete beam elements at the riveted joint. This method will be used to predict the dynamics modes of the structure. To validate the FE model, a prototype server rack was subjected to side to side vibration tests. A sine sweep vibration test identifies dominant mode shapes and the transmissibility of the input vibration. The results of the tests on the prototype rack serve as input for FE model refinement. The test data show that representing the riveted joints with beams does provide results that closely match the actual test data. A validated FE model will be used to evaluate dominant vibration modes for several configurations of rack weight as well as configurations to stiffen the structure in the side to side direction. The dynamic mode shapes visualize the effect of stiffening brackets on dominant frequencies of the rack. The optimal stiffening design will be the one that results in the minimum deflection under the standard testing profile.
Plastic Loads for Cones Subjected to Internal Pressure and Axial Tension
Authors: Błachut J. , Sala D. 
Published: October 2017

The paper discusses envelopes of combined loading corresponding to: (i) first yield (ii) plastic load, and (iii) plastic instability load. The latter two were researched in the past but for a single load, only. The past idea has been expanded in the paper to two, practically relevant, simultaneously acting loads. Conical shell serves here as an example.
It is shown that the ratio of area of plastic load envelope to the area associated with the first-yield envelope is 3.2 whilst the similar ratio of plastic instability to the first-yield envelope amounts to 25.8. This indicates ‘a modest’ (320 %) increase of possible range of loading, and a substantial reserve of strength above the end-of-elastic behavior (approx. 26-times).
Failure Mode of ED and AD Type Head Plates Subject to Convex Side Pressure
Authors: Yada Hiroki , Ando Masanori , Tsukimori Kazuyuki , Ichimiya Masakazu , Anoda Yoshinari 
Published: October 2017

Containment vessel is an important structure to prevent a significant and sudden radioactive release, however, the safety margin of the containment vessel against the internal or external pressure are not numerically clarified. Namely, the safety margins due to the relationship of the ultimate toughness of containment vessel structures and maximum design pressure is not clear. Indeed, to clarify the progress of events under the beyond design basis events (BDBE) and to design the BDBE countermeasure equipment, it is necessary to evaluate the pressure toughness of containment vessel adequately. The containment vessel of fast reactor is composed of the various structures. The head plate that composes the boundary between primary and secondary coolant in intermediate heat exchanger has an important role when the progress of the BDBE is considered. Therefore, in order to develop the evaluation method of the pressure toughness of the head plate under the BDBE, the pressure failure tests and finite element analysis of head plate structure subjected to convex side pressure was performed in this study.
Two types of head plates were applied for pressure failure tests. ED type and AD type head plates were chosen as a representative to clarify the effect of shape. These head plates have 250mm diameter and 3mm thickness. The head plates were subjected to pressure on convex side by water in the pressure failure tests. In tests, almost completely inside-out of each head plate was caused after buckling.
Then after that, leakage was observed near the rim. Two types of head plates had similar failure mode in spite of difference original shapes. The circumferential through-wall crack was observed near the rim of each head plates.
According to the results of pressure failure tests, it is seemed that the circumferential crack was caused by straightening following bending associated with large deformation as inside-out. To clarify the relationship between bending radius and crack initiation, straightening following the bending deformation (bending-straightening) tests were performed.
As a result, the crack was initiated in the test case of the bending radius smaller than 3 mm. 3 mm of bending radius generate 33 % strain. The bending radius at the time of leakage observed of head plates was estimated almost similar value at which crack initiated. Therefore, it can be concluded that a failure mode of a head plate subjected convex side pressure is circumferential through-wall crack caused by straightening following bending deformation near the rim.
INCEFA-PLUS (Increasing Safety in Nuclear Power Plants by Covering Gaps in Environmental Fatigue Assessment)
Authors: Mottershead Kevin , Bruchhausen Matthias , Métais Thomas , Cicero Sergio , Tice David 
Published: October 2017

INCEFA-PLUS is a five year project supported by the European Commission HORIZON2020 program. The project commenced in mid-2015. 16 organizations from across Europe have combined forces to deliver new experimental data which will support the development of improved guidelines for assessment of environmental fatigue damage to ensure safe operation of nuclear power plants. Within INCEFA-PLUS, the effects of mean strain, hold time, strain amplitude and surface finish on fatigue endurance of austenitic stainless steels in light water reactor environments are being studied experimentally, these being issues of common interest to all participants. The data obtained are being collected and standardized in an online environmental fatigue database, implemented with the assistance of a CEN workshop led by members of the INCEFA-PLUS project. Later in the project it is planned that INCEFA-PLUS will develop and disseminate methods for including the new data into assessment approaches for environmental fatigue degradation.
This paper provides an update to the project introduction presented at PVP2016 (PVP2016-63149). In particular the paper presents the finalized matrix of test conditions for Phase 1 testing planned for 2017, including the agreed positions on testing for the effects of mean stress/strain and hold time. The materials being tested are summarized, together with available material characterization data. The specimen surface finishes used in the phase 1 testing are described, including measures taken to ensure uniformity of surface conditions throughout the consortium and characterization results for the two chosen surface finishes for each specimen geometry and material. The emerging plans for Phase 2 testing is also described, with a focus on steps being taken to enable more plant-relevant testing for the effects of mean stress and exploration of sensitivities to hold times within plant transients. The latest view on how the project results will be used to advance development of improved assessment guidelines is also discussed. An update is provided on the discussions at the CEN workshop on Standards-Compliant Formats for Fatigue Test Data (FATEDA) including progress towards agreeing test data formats and trials of XML data transfers from laboratory to database. Finally, a summary is provided of project dissemination activities.