Large Scale Modelling of Damage and Failure of Nuclear Graphite Moderated Reactor

The UK Advanced Gas-Cooled reactors (AGRs) have cores made of graphite bricks with dual functions: as structural elements of the core, providing space for and separating fuel and control rods; and as moderator of the nuclear reaction. Nuclear graphite is a quasi-brittle material, where the dominant mechanism for failure is cracking. While cracking of isolated bricks is expected due to operation-induced changes in graphite microstructure and stress fields, these could be tolerated as far as the overall structural function of the core is maintained. Assessment of the whole core behaviour has been previously done with whole scale models where bricks have been considered as rigid body elements connected by elastic-brittle springs. This approach does not allow for the realistic assessment of the stresses in the bricks and associated brick cracking. Reported here are results from an ongoing project, which addresses this shortcoming. The proposed model uses deformable bricks with appropriate interactions, allowing for physically realistic whole core analysis. The results are focused on the damage that a graphite moderated reactor develops during a life cycle, how this affects the behaviour of the whole core, and how changes in bricks' behaviour impacts the core integrity. The proposed methodology is a major step towards high-fidelity assessment of AGRs' fitness for service, required for supporting continuous safe operation and life-extension decisions.

Lipid Profiles of the Heads of Four Shrimp Species by UPLC–Q–Exactive Orbitrap/MS and Their Cardiovascular Activities

Lipids are key factors in nutrition, structural function, metabolic features, and other biological functions. In this study, the lipids from the heads of four species of shrimp (Fenneropenaeus chinensis (FC), Penaeus japonicus (PJ), Penaeus vannamei (PV), and Procambarus clarkia (PCC)) were compared and characterized based on UPLC–Q–Exactive Orbitrap/MS. We compared the differences in lipid composition of four kinds of shrimp head using multivariate analysis. In addition, a zebrafish model was used to evaluate pro-angiogenic, anti-inflammatory, anti-thrombotic, and cardioprotective activities of the shrimp head lipids. The lipids from the four kinds of shrimp head had different degrees of pro-angiogenic activities, and the activities of PCC and PJ shrimp lipids were more significant than those of the other two species. Four lipid groups displayed strong anti-inflammatory activities. For antithrombotic activity, only PCC (25 μg/mL) and PV (100 μg/mL) groups showed obvious activity. In terms of cardioprotective activity, the four kinds of lipid groups significantly increased the zebrafish heart rhythms. The heart distances were shortened, except for those of the FC (100 μg/mL) and PJ (25 μg/mL) groups. Our comprehensive lipidomics analysis and bioactivity study of lipids from different sources could provide a basis for the better utilization of shrimp.

A Generalized Non-Parametric Instrumental Variable-Control Function Approach to Estimation in Nonlinear Settings

When the endogenous variables enter non-parametrically into the regression equation standard linear instrumental variables approaches fail. Two existing solutions are the non-parametric instrumental variables (NPIVs) estimators, which are based on a set of conditional moment restrictions (CMRs), and the control function (CF) estimators, which use conditional mean independence (CMI) restrictions. Our first contribution is to show that – similar to CMI – the CMR place shape restrictions on the conditional expectation of the error given the instruments and endogenous variables that are sufficient for identification, and we call our new estimator based on these restrictions the CMR-CF estimator. Our second contribution is to develop an estimator for non-linear and non-parametric settings that can combine both CMR and CMI restrictions, which cannot be done in either the NPIV nor the non-parametric CF setting. This new “Generalized CMR-CF” uses both CMR and CMI restrictions together by allowing the conditional expectation of the structural error to depend on both instruments and control variables. When sieves are used to approximate both the structural function and the CF our estimator reduces to a series of least squares regressions. Our Monte Carlos illustrate that our new estimator performs well across several economic settings.

The Role of Sphingolipids Metabolism in Cancer Drug Resistance

Drug resistance continues to be one of the major challenges to cure cancer. As research in this field evolves, it has been proposed that numerous bioactive molecules might be involved in the resistance of cancer cells to certain chemotherapeutics. One well-known group of lipids that play a major role in drug resistance are the sphingolipids. Sphingolipids are essential components of the lipid raft domains of the plasma membrane and this structural function is important for apoptosis and/or cell proliferation. Dysregulation of sphingolipids, including ceramide, sphingomyelin or sphingosine 1-phosphate, has been linked to drug resistance in different types of cancer, including breast, melanoma or colon cancer. Sphingolipid metabolism is complex, involving several lipid catabolism with the participation of key enzymes such as glucosylceramide synthase (GCS) and sphingosine kinase 1 (SPHK1). With an overview of the latest available data on this topic and its implications in cancer therapy, this review focuses on the main enzymes implicated in sphingolipids metabolism and their intermediate metabolites involved in cancer drug resistance.

Mechanical Properties of a 3D Printed Wall Segment Made with an Earthen Mixture

This paper is part of the research on 3D printing of earthen housing modules, made with earth taken in situ. Previous studies have already led to the definition of 3D printed earthen elements for the external cladding of single-story wooden load-bearing structures. With this work, we intend to take a step forward in the use of 3D printed earthen elements, studying their load-bearing capacity for vertical loads. The goal is to create load-bearing structures entirely in earth, with two or more floors. To this end, the present work investigates two of the major presumed criticalities of 3D printed elements under vertical load, namely the detachments due to poor cohesion between extruded layers and the detachments between internal infill and external coating. The uniaxial compression test on a specially 3D printed wall segment did not actually show any particular danger for the stability of the structure, due to detachment phenomena. Rather, the experimental results showed some quite anomalous mechanical behaviors for a brittle construction material (studied at the mesoscale), especially as regards Poisson’s modulus and volumetric strain. The main experimental finding concerns the contribution of the internal infill, which seems to have a structural function and not just a filling function.

Understanding expressive intonation

Research on intonation has mainly sought for classifying and/or expressive explanations for performers’ strategies. In the field of music psychology and music perception, such explanations have been explored in terms of interval direction, size, or type; in the field of performance analysis, to which this article belongs, investigation on intonation has been not only scarce but also limited to short excerpts. In this context, this article explores Pau Casals’ intonational practice specific to his recording of Bach’s E flat major prelude for solo cello. To do so, on the basis of exact empirical measurements, it places such practice alongside the cellist’s conscious, theoretical recommendations apropos what he called “expressive” string intonation, showing that the interpretation of the latter should is not straightforward. It also proposes several reference points and tuning systems which could serve as models for Casals’ practice and looks for explanations beyond simple interval classification. In this manner, it ultimately proposes a structural function for intonation, in partnership with tempo and dynamics. Similarly, it understands Casals’ intonational practice not as a choice between but as a compromise for multiple options in tuning systems (mostly equal temperament and Pythagorean tuning), reference points (the fundamental note of the chord and the immediately preceding tone), the nature of the compositional materials (harmonic and melodic), and, most importantly, structure and expression.

Anisotropy of turbulent flow behind an asymmetric airfoil

Feature of turbulent flow anisotropy behavior behind an asymmetric NACA 64-618 airfoil investigated in this paper. Experimental studies were performed using a hot-wire anemometery with X-probe at the chord-based Reynolds number $$1.7 \times 10^5$$ 1.7 × 10 5 . The average ensemble velocity and Reynolds stress components are used to determine the wake topology and anisotropy of turbulence. The obtained data allowed to identify the outside wake region, which is characterized by low instability and a high degree of anisotropy of the turbulent flow. This tendency is observed at different angles incident. Further, to gain better insight into the physics of this phenomenon the structure of turbulence have been evaluated. Integral turbulence length and time scales were estimated by the area of the autocorrelation function of velocity fluctuations. Then, using the second-order structural function, we obtained the dissipation characteristics of the flow. In addition, the features of the energy spectrum in the region with high and low degrees of turbulence anisotropy were analyzed.

Put to the Test: The Folk-­Tale Motif of the "Test to Prove Worthiness" in Three of Shakespeare's Comedies

<p>Critics have recognised folk‐tales as being among the varied sources Shakespeare has mined for the plots of his plays. However, this recognition has often formed the basis of an argument which seeks to excuse what are perceived as flaws in Shakespeare’s plays, for example claiming that humanised characters jostle against their folk‐tale or popular culture archetypes, or that friction is generated when a folk‐tale plot is placed into a realistic setting. There has been little examination of Shakespeare’s relationship to his sources from folk‐tale, and so in this thesis I use the motif of the “test imposed to prove worthiness” (Stith Thompson’s Motif H900) as an example of the way Shakespeare develops, doubles and ultimately subverts these sources. I examine three comedies which employ this motif: The Taming of the Shrew, The Merchant of Venice and All’s Well That Ends Well. In the first play I argue that the testing of Katherina’s obedience rebounds to test Petruccio’s masculinity. In The Merchant, I argue that the casket test and doubled ring test play a crucial role in the development of Bassanio’s worthiness and loyalty, simultaneously casting doubt on Portia’s faithfulness. Finally, in relation to All’s Well, I argue that the test motif and by extension its folk‐tale sources are subverted so that the impossible tasks rebound not only on Bertram, but on the play as a whole, testing the genres of romance and realism. I find that testing cycles have a structural function as they fall between the couples’ weddings and consummations. Because of this placement, they are linked to private and public anxieties about sexuality and fidelity, in turn demonstrating their thematic function. The development, doubling and subversion of folk‐tales allow Shakespeare to explore ideas fully, often contrapuntally. Thus, my thesis seeks to address the gap in the critical studies by contending that Shakespeare makes innovative use of his folk‐tale sources. While ambiguity is certainly generated in each of the three plays, this is a deliberate effect rather than a flaw; no apology is required.</p>

Put to the Test: The Folk-­Tale Motif of the "Test to Prove Worthiness" in Three of Shakespeare's Comedies

<p>Critics have recognised folk‐tales as being among the varied sources Shakespeare has mined for the plots of his plays. However, this recognition has often formed the basis of an argument which seeks to excuse what are perceived as flaws in Shakespeare’s plays, for example claiming that humanised characters jostle against their folk‐tale or popular culture archetypes, or that friction is generated when a folk‐tale plot is placed into a realistic setting. There has been little examination of Shakespeare’s relationship to his sources from folk‐tale, and so in this thesis I use the motif of the “test imposed to prove worthiness” (Stith Thompson’s Motif H900) as an example of the way Shakespeare develops, doubles and ultimately subverts these sources. I examine three comedies which employ this motif: The Taming of the Shrew, The Merchant of Venice and All’s Well That Ends Well. In the first play I argue that the testing of Katherina’s obedience rebounds to test Petruccio’s masculinity. In The Merchant, I argue that the casket test and doubled ring test play a crucial role in the development of Bassanio’s worthiness and loyalty, simultaneously casting doubt on Portia’s faithfulness. Finally, in relation to All’s Well, I argue that the test motif and by extension its folk‐tale sources are subverted so that the impossible tasks rebound not only on Bertram, but on the play as a whole, testing the genres of romance and realism. I find that testing cycles have a structural function as they fall between the couples’ weddings and consummations. Because of this placement, they are linked to private and public anxieties about sexuality and fidelity, in turn demonstrating their thematic function. The development, doubling and subversion of folk‐tales allow Shakespeare to explore ideas fully, often contrapuntally. Thus, my thesis seeks to address the gap in the critical studies by contending that Shakespeare makes innovative use of his folk‐tale sources. While ambiguity is certainly generated in each of the three plays, this is a deliberate effect rather than a flaw; no apology is required.</p>