The k0-INRIM software version 2.0: presentation and an analysis vademecum

The k0-INRIM software was developed at INRIM to perform k(0)-standardization Neutron Activation Analysis and evaluate combined uncertainty through application of the spreadsheet method. However, the presence of some limitation made its use, as a tool for routine NAA, impractical. With the aim to participate to the 2021 IAEA k(0)-NAA software intercomparison to evaluate the effect on mass fraction results due to software used, the k0-INRIM was sizably updated in order to meet the agreed functionality requirements to take part to the exercise. In this work, the version 2.0 of the software is presented and a point-by-point example analysis is displayed. The software version here described is available for download together with the corresponding updated user's manual

Mapping Moho depth variations in central Italy from PsMoho-P delay times: Evidence of an E-W transition in the Adriatic Moho at 42°N latitude

Along the Italian peninsula adjoin two crustal domains, peri-Tyrrhenian and Adriatic, whose boundary is not univocal in central Italy. In this area, we attempt to map the extent of the Moho in the two terrains from variations of the travel time difference between the direct P wave and the P-to-S wave converted at the crust-mantle boundary, called PsMoho. We use teleseismic receiver functions computed at 38 broad-band stations in this and previous studies, and assigned each of the recording sites to the Adriatic or peri-Tyrrhenian terrains based on station location, geologic and geophysical data and interpretation, and consistency of delays with the regional Moho trend. The results of the present study show that the PsMoho arrival time varies from 2.3 to 4.1 s in the peri-Tyrrhenian domain and from 3.7 to 5.5 s in the Adriatic domain. As expected, the lowest time difference is observed along the Tyrrhenian coastline and the largest values are observed in the axial zone of the Apennine chain. A key new result of this study is a sharp E-W boundary in the Adriatic domain that separates a deeper Moho north of about 42 N latitude from a shallower Moho to the south. This feature is constrained for a length of about 40 km by the observations available in this study. The E-W boundary requires a revision of prior mapping of the Moho in central Italy and supports previous hypotheses of lithosphere segmentation

Numerical modelling via a coupled discrete approach of the autogenous healing for Fibre-Reinforced Cementitious Composites (FRCCs)

Aiming to predict long-term performance of advanced cement-based materials and design more durable structures, a reliable modelling of the autogenous healing of cementitious materials is crucial. A dis-crete model for the regain in terms of water tightness, stiffness and strength induced by the autogenous and/or “stimulate" autogenous healing was recently proposed for ordinary plain concrete. The modelling proposal stemmed from the coupling of two models, namely the Hygro-Thermo-Chemical (HTC) model, on one side,and the Lattice Discrete Particle Model (LDPM), on the other side, resulting in the Multiphysics-Lattice Discrete Particle Model (M-LDPM). Being this approach not customised only for ordinary concrete, but for the whole broad category of cementitious materials, in this paper, its application to Fibre-Reinforced Cementitious Composites is presented. To accurately simulate what has been experimentally observed so far, the mechanical model is updated to also include the self-healing of the tunnel cracks at the fibre-matrix interfaces. Therefore,the self-repairing process is modelled to develop on two independent stages: (a) matrix cracks healing, and(b) fibre bridging action restoring. This research activity is part of the modelling tasks framed into the project ReSHEALience, funded from the European Union’s Horizon 2020 Research and Innovation Programme

Hygro-thermo-chemo-mechanical coupled discrete model for the self-healing in Ultra High Performance Concrete

Reliable durability predictions and design for advanced cement-based materials cannot disregard the modelling of their inherent self-healing capability. A discrete meso-scale model to simulate the recovery in water tightness, stiffness and strength induced by the (stimulated) autogenous healing of cracks for Ultra High Performance Concrete is presented. In this paper the model is implemented into the numerical framework of the Multiphysics-Lattice Discrete Particle Model (M-LDPM), resulting from the coupling of the Hygro-Thermo-Chemical (HTC) model and Lattice Discrete Particle Model (LDPM). Consistently with experimental evidence, the development of the self-repairing process is modelled as consisting of two independent stages: (a) the healing of matrix cracks, affecting both moisture permeability and fracture strength in the cracked state, and (b) the recovery in terms of fibre bridging action, relying on the adhesion between the healing products and the walls of the tunnel cracks which form during the fibre debonding process. This research activity is framed into the Horizon 2020 project ReSHEALience (GA 760824)

Potential rockfalls and analysis of slope dynamics in the palatine archaeological area (Rome, Italy)

The Palatine Hill is among the main archaeological sites of Roman antiquity. Today, this place requires continuous care for its safeguarding and conservation. Among the main problems, slope instabilities threaten the southwestern border of the hill flanked by the Velabrum Valley, as also testified by historical documents. The upper part of the investigated slope is characterized by Middle Pleistocene red-brownish tuffs known as "Tufo Lionato". The rock mass is affected by two jointing belts featuring the slope edge and its internal portion with different joint frequency and distribution. The analysis of the geometric relationship between the joint systems and the slope attitude evidenced possible planar sliding and toppling failure mechanisms on the exposed tuff cliffs. Potential rock block failures threatening the local cultural heritage were contrasted with preliminary works for site remediation. In addition, stress-strain numerical modelling verified the hypothesis of a tensile origin for the jointing belts, suggested by fracture characteristics and orientation. A first modelling was limited to the southwestern edge of the Palatine Hill and analysed the present stress-strain condition of the slope, proving the inconsistency with the observed deformation. A second modelling was extended to the Palatine-Velabrum slope-to-valley system to consider the role played by the geomorphological evolution of the area on the local slope dynamics during the late Pleistocene-Holocene. Results demonstrate how original conditions of slope instability, deformation and retreat along the Palatine western edge were determined by deep valley incision, and controlled by deformability contrasts within the slope. Slope instability influenced the site occupation and development during the Roman civilization, as also indicated by the remnants of retaining walls of different ages at the slope base

Tertiary creep in concrete

Time dependent concrete fracture is simulated using a rate type creep model coupled with a discrete concrete model. The numerical study uses experimental data, of various tests, three point bending, relaxation, tensile, performed on concrete. This contribution demonstrates the capability of the model to capture the time dependent fracture behavior of concrete, and predicts the critical time of failure

Cohesive crack analysis of size effect for samples with blunt notches and generalized size effect curve for quasi-brittle materials

This paper deals with the study of size effect on structural strength for quasi-brittle materials under mode I fracture conditions. By using a linear cohesive crack model, accurate numerical simulations were performed to compute the size effect curves for two test configurations – namely, the three-point bending test with span-to-depth ratio equal to 3 and the center crack panel test – featuring sharp notches and blunt notches whose width is also scaled with the specimen dimension. The analysis of the results shows that, as the specimen size tends to infinity, the asymptotic behavior depends on the type of notch. For sharp notches the size effect curve tends asymptotically to Bažant's Size Effect Law. On the contrary, for blunt notches the size effect curve tends to a horizontal asymptote corresponding to the elastic limit. The elastic limit can be calculated by the tensile strength reduced by the stress concentration factor at the tip of the blunt notch and it depends on the geometry of the specimen. Furthermore, the numerical results were utilized to derive the expression of a Generalized Cohesive Size Effect Curve (GCSEC) which agrees well with Bažant's Universal Size Effect Law (USEL) and with some experimental data gathered from the literature

Modelling of autogenous healing for regular concrete via a discrete model

In this paper a numerical model for autogenous healing of normal strength concrete is presented in detail, along with preliminary results of its validation, which is planned to be achieved by comparing the results of numerical analyses with those of a dedicated experimental campaign. Recently the SMM (Solidification-Microprestress-Microplane model M4) model for concrete, which makes use of a modified microplane model M4 and the solidification-microprestress theory, has been extended to incorporate the autogenous healing effects. The moisture and heat fields, as well as the hydration degree, are obtained from the solution of a hygro-thermo-chemical problem, which is coupled with the SMM model. The updated model can also simulate the effects of cracking on the permeability and the restoring effect of the self-healing on the mechanical constitutive laws, i.e. the microplane model. In this work, the same approach is introduced into a discrete model, namely the Lattice Discrete Particle Model (LDPM). A numerical example is presented to validate the proposed computational model employing experimental data from a recent test series undertaken at Politecnico di Milano

Advancement of a Soil Parameters Geodatabase for the Modeling Assessment of Conservation Practice Outcomes in the United States

US-ModSoilParms-TEMPLE is a database composed of a set of geographic databases functionally storing soil-spatial units and soil hydraulic, physical, and chemical parameters for three agriculture management simulation models, SWAT, APEX, and ALMANAC. This paper introduces the updated US-ModSoilParms-TEMPLE, which covers the entire United States and is organized as a framework of 22 nested and hydrologically-ordered regional geographic databases with internal spatial segmentation drainage-defined at a conveniently manageable tile (Watershed Boundary Dataset’s, WBD, 8-digit Subbasin) level. Spatial features are stored in multiple formats (raster and vector) and resolutions (10-meter and 30-meter), while being in direct relationship with the table of attributes storing the models’ parameters. A significant number of former parameter voids, determined by the local incompleteness of the source datasets, were filled using a methodology leveraging upon the hierarchy of the Soil Taxonomy information and the geographic location of the gaps. The functionality of each geographic database was extended by adding customized tools, which streamline the incorporation into geoprocessing workflows, the aggregation and extraction of data sets, and finally the export to other model support software user environments. These tools are attached and conveniently distributed along with detailed metadata documentation within each of the developed regional geographic databases. The system hosting this framework is developed using a proprietary software format (ESRI® File Geodatabase), however, a companion version of the framework of 8-digit tiles is also developed and provided using openly accessible formats. The experience shared in this paper might help other efforts in developing hydrology-oriented geographical databases