Influence of severe thermal preconditioning on the bond between carbon FRCM and masonry substrate: Effect of textile pre-impregnation

Fabric-reinforced cementitious matrix (FRCM) composites often include polymer-impregnated bundles to improve the exploitation of the textile mechanical properties. However, organic components may degrade when exposed to elevated temperature. In this paper, the bond behavior of a carbon FRCM applied to a masonry substrate and exposed to a thermal preconditioning up to 300 °C for 250 min is investigated. Tensile tests on the textile and flexural and compression tests on the mortar matrix, as well as single-lap direct shear tests of FRCM-masonry joints with bare and impregnated textiles, are performed. Results show that the polymeric impregnation improves the mechanical properties of the FRCM even after thermal preconditioning

Bending and shear behavior of historic walls strengthened with composite reinforced mortar

Composite reinforced mortar (CRM) is a relatively new solution for the strengthening of existing masonry members that comprises fiber-reinforced polymer (FRP) grids reinforcing inorganic mortar overlays. CRMs were proven to be effective in strengthening masonry members against in- and out-of- plane loads. In this paper, a glass FRP-CRM is employed to strengthen 5-leaf historic masonry walls cut from an existing building located in Milan, Italy. The walls were strengthened and then subjected to three-point bending and diagonal compression tests. Results were compared with those of corresponding non-strengthened walls and showed the CRM effectiveness also in the case of thick masonry members

Effect of cyclic load on the tensile behavior of a PBO FRCM composite

The use of externally bonded fiber-reinforced cementitious matrix (FRCM) composites represents a valid alternative to traditional techniques for the strengthening and retrofitting of existing reinforced concrete and masonry structures. FRCM composites are comprised of high strength textiles embedded within inorganic matrices and can be directly applied to the external surface of the existing structural element to increase its displacement and load capacity (i.e., axial, flexural, and shear strength). Thus, FRCM have a low invasiveness and a high strength-to-weight ratio. Recently, investigations on the bond behavior of FRCM composites showed that the presence of friction between the textile and matrix can induce damage to the fiber, which in turn determines possible reductions in the strengthened element capacity. This effect appears particularly critical in the case of cyclic and dynamic loads. In this paper, the cyclic behavior of a PBO FRCM composite is experimentally investigated using low-cycle tensile tests on composite specimens. Namely, FRCM rectangular coupons are subjected to clamping- and clevis-grip tensile tests. These tests provide important information on the effect of low-frequency dynamic loading on the composite tensile properties under different test configurations

The i-process and CEMP-r/s stars

© Copyright owned by the author(s) under the terms of the Creative Commons Attribution-NonCommercial-ShareAlike Licence. We investigate whether the anomalous elemental abundance patterns in some of the C-enhanced metal-poor-r/s (CEMP-r/s) stars are consistent with predictions of nucleosynthesis yields from the i-process, a neutron-capture regime at neutron densities intermediate between those typical for the slow (s) and rapid (r) processes. Conditions necessary for the i-process are expected to be met at multiple stellar sites, such as the He-core and He-shell flashes in low-metallicity low-mass stars, super-AGB and post-AGB stars, as well as low-metallicity massive stars. We have found that single-exposure one-zone simulations of the i-process reproduce the abundance patterns in some of the CEMP-r/s stars much better than the model that assumes a superposition of yields from s and r-process sources. Our previous study of nuclear data uncertainties relevant to the i-process revealed that they could have a significant impact on the i-process yields obtained in our idealized one-zone calculations, leading, for example, to ∼ 0:7dex uncertainty in our predicted [Ba/La] ratio. Recent 3D hydrodynamic simulations of convection driven by a He-shell flash in post-AGB Sakurai's object have discovered a new mode of non-radial instabilities: the Global Oscillation of Shell H-ingestion. This has demonstrated that spherically symmetric stellar evolution simulations cannot be used to accurately model physical conditions for the i-process

Topography of the Dolomites modulates range dynamics of narrow endemic plants under climate change

open9noClimate change is expected to threaten endemic plants in the Alps. In this context, the factors that may modulate species responses are rarely investigated at a local scale. We analyzed eight alpine narrow endemics of the Dolomites (southeastern Alps) under different predicted climate change scenarios at fine spatial resolutions. We tested possible differences in elevation, topographic heterogeneity and velocity of climate change among areas of gained, lost, or stable climatic habitat. The negative impact of climate change ranged from moderate to severe, depending on scenario and species. Generally, range loss occurred at the lowest elevations, while gained and stable areas were located at highest elevations. For six of the species, climate change velocity had higher values in stable and gained areas than in lost ones. Our findings support the role of topographic heterogeneity in maintaining climatic microrefugia, however, the peculiar topography of the Dolomites, characterized by high altitude plateaus, resulted in high climate change velocity in areas of projected future climatic suitability. Our study supports the usefulness of multiple predictors of spatio-temporal range dynamics for regional climate-adapted management and eventual assisted colonization planning to not overlook or overestimate the potential impact of climate change locally.openRota F.; Casazza G.; Genova G.; Midolo G.; Prosser F.; Bertolli A.; Wilhalm T.; Nascimbene J.; Wellstein C.Rota, F.; Casazza, G.; Genova, G.; Midolo, G.; Prosser, F.; Bertolli, A.; Wilhalm, T.; Nascimbene, J.; Wellstein, C

L'importanza ecologica e fitoalimurgica dei prati ricchi di specie del Trentino

Il cambiamento del sistema foraggero-zootecnico, da estensivo a intensivo, ha determinato la progressiva sostituzione del letame con il liquame. L’uso del liquame come fertilizzante riduce l’oligotrofia del suolo e porta alla banalizzazione delle fitocenosi erbacee. Nell’ambito del progetto Bioagrimont sono state indagate con metodo floristico-vegetazionale e statistico 25 fitocenosi (plots 5m x 5m) prato-pascolive a diversa gestione e quota altimetrica delle valli di Fiemme, di Fassa e Passo di Lavazè. I risultati confermano la correlazione negativa tra ricchezza floristica (S) e apporto di nutrienti (N) ed evidenziano una sensibile perdita del valore naturalistico per i prati del fondovalle. Si dimostra inoltre che le praterie a maggior ricchezza floristica, legate a ridotto o nullo apporto di nutrienti, funzionano da serbatoio di specie potenzialmente utili anche a livello alimentare e officinal

Implicit mapping of pointers inside C++ Lambda closure objects in OpenMP target offload regions

With the diversification of HPC architectures beyond traditional CPU-based clusters, a number of new frameworks for performance portability across architectures have arisen. One way of implementing such frameworks is to use C++ templates and lambda expressions to design loop-like functions. However, lower level programming APIs that these implementations must use are often designed with C in mind and do not specify how they interact with C++ features such as lambda expressions. This paper proposes a change to the behavior of the OpenMP specification with respect to lambda expressions such that when functions generated by lambda expressions are called inside GPU regions, any pointers used in the lambda expression correctly refer to device pointers. This change has been implemented in a branch of the Clang C++ compiler and demonstrated with two representative codes. Our results show that the implicit mapping of lambda expressions always exhibits identical performance to an explicit mapping but without breaking the abstraction provided by the high level frameworks, and therefore also reduces the burden on the application developer

Pointers inside lambda closure objects in OpenMP target offload regions

With the diversification of HPC architectures beyond traditional CPU-based clusters, a number of new frameworks for performance portability across architectures have arisen. One way of implementing such frameworks is to use C++ templates and lambda expressions to design loop-like functions. However, lower level programming APIs that these implementations must use are often designed with C in mind and do not specify how they interact with C++ features such as lambda expressions. This paper discusses a change to the behavior of the OpenMP specification with respect to lambda expressions such that when functions generated by lambda expressions are called inside GPU regions, any pointers used in the lambda expression correctly refer to device pointers. This change has been implemented in a branch of the Clang C++ compiler and demonstrated with two representative codes. This change has also been accepted into the draft OpenMP specification for inclusion in OpenMP 5. Our results show that the implicit mapping of lambda expressions always exhibits identical performance to an explicit mapping but without breaking the abstraction provided by the high level frameworks