An orthotropic macromechanical model with damage for the analysis of masonry structures

The in-plane response of masonry walls is analyzed by using a novel macromechanical damage model. This is able to capture the directional mechanical properties characterizing regular masonry textures by adopting an orthotropic description of the elastic and inelastic behavior. A damage matrix, defined in terms of damage independent scalar variables, is introduced in the constitutive law to describe and distinguish the stiffness degradation due to tensile, compressive and shear states along masonry natural axes, fixed as the parallel and normal direction to bed joints. The model is implemented in a finite element procedure, where the mesh-dependency drawback is overcome by adopting a classical nonlocal integral approach. Comparisons of numerical and experimental results are performed to test the model capability of describing influence of the orientation of applied stresses with respect to bed joints direction. Moreover, a numerical study is conducted with reference to different masonry textures with the aim of evaluating the effect of bricks and mortar relative arrangement on the elastic properties of the homogenized material. Finally, the response of a large scale masonry wall subjected to seismic loads is studied and the obtained pushover curve is compared with those collected from existing literature models

Dynamic characterization of a system with degradation: A masonry wall

Characterization of the dynamic behavior of linear systems is exhaustively described with a single frequency response curve (frc). For nonlinear systems, which tend to depend on load amplitude, at least one frc for each excitation intensity is required to detect the main characteristics of the dynamic response. Nonlinear systems, more commonly dealt with in the literature, are invariant with respect to the deformation history and, thus, frcs obtained with increasing and decreasing driving frequency coincide, apart from the frequency range with coexistent solutions. This is not so for many real systems which suffer from their past, often exhibiting degradation of their mechanical properties. Here the focus is on the effects of damage on the dynamic signature of systems. The response of a masonry wall, representative of systems with a degrading restoring force, is analyzed under harmonic excitation. A refined finite element model is used to represent the typical degradation that occurs in masonry and its reliability is proved by comparing numerical results and experimental outcomes from shaking table tests. Particular attention is paid to the wall frcs, emphasizing the influence of the deformation history on the curves characteristics and their role in the dynamic characterization of a system with degradation

Inference of gene regulatory networks and compound mode of action from time course gene expression profiles.

MOTIVATION: Time series expression experiments are an increasingly popular method for studying a wide range of biological systems. Here we developed an algorithm that can infer the local network of gene-gene interactions surrounding a gene of interest. This is achieved by a perturbation of the gene of interest and subsequently measuring the gene expression profiles at multiple time points. We applied this algorithm to computer simulated data and to experimental data on a nine gene network in Escherichia coli. RESULTS: In this paper we show that it is possible to recover the gene regulatory network from a time series data of gene expression following a perturbation to the cell. We show this both on simulated data and on a nine gene subnetwork part of the DNA-damage response pathway (SOS pathway) in the bacteria E. coli

Effect of oils administration on diets digestibility and haematic fatty acids profile in exercising horses

The ration of performance horse usually includes great amount of cereals. Nevertheless there is a limit to the amount of starch which a ration should contain. Addition of dietary fat to improve the caloric density of horse mixed feed is a common practice. Fat supplement reduces the negative effect of excessive starch fermentations in large intestine

Strain partitioning in host rock controls LREE release from allanite-(Ce) in subduction zones

Combined microstructural, mineral chemical, X-ray maps, and X-ray single-crystal diffraction analyses are used to reveal the rheological behaviour of individual grains of magmatic allanite relicts hosted in variably deformed metagranitoids at Lago della Vecchia (inner part of the Sesia-Lanzo Zone, Western Alps, Europe), which experienced high pressure and low temperature metamorphism during the Alpine subduction. X-ray single crystal diffraction shows that none of the allanite crystals, irrespective of the strain state of the host rock, record any evidence of plastic deformation (i.e., intracrystalline deformation), as indicated by the shape of the Bragg diffraction spots, the atomic site positions, and their displacement around the centre of gravity. On the contrary, strong plastic deformation affected matrix minerals, such as quartz, white mica, and feldspar of the hosting rocks, during the development of the Alpine eclogitic- and blueschist-facies metamorphism. Despite the strain-free atomic structures of allanite, different patterns of chemical zoning, as a function of strain accumulated in the rock matrix, are observed. Since allanite occurs in magmatic and metamorphic rocks and it is stable at high pressure and low temperature conditions, we infer that allanite could behave as one of the main carriers of light-rare-earth-elements into the mantle wedge during subduction of continental crust. In particular, the release of light-rare-earth-elements from allanite, under high pressure conditions in subduction zones, is facilitated by high strain accumulated in the host rock

Development and distribution of the non-indigenous Pacific oyster (Crassostrea gigas) in the Dutch Wadden Sea

Pacific oysters (Crassostrea gigas) were first observed in the Dutch Wadden Sea near Texel in 1983. The population increased slowly in the beginning but grew exponentially from the mid-1990s onwards, although now some stabilisation seems to be occurring. They occur on a variety of substrates such as mussel beds (Mytilus edulis), shell banks, dikes and poles. After initial settlement spat may fall on older individuals and congregate to dense clumps and subsequently form reefs. Individual Pacific oysters grow 3–4 cm long in their first year and 2–3 cm in their second year. Many mussel beds (Mytilus edulis) are slowly taken over by Pacific oysters, but there are also several reports of mussel spat settling on Pacific oyster reefs. This might in the end result in combined reefs. Successful Pacific oyster spat fall seems to be related to high summer temperatures, but also after mild summers much spat can be found on old (Pacific oyster) shells. Predation is of limited importance. Mortality factors are unknown, but every now and then unexplained mass mortality occurs. The gradual spread of the Pacific oyster in the Dutch Wadden Sea is documented in the first instance based on historical and anecdotal information. At the start of the more in-depth investigation in 2002, Pacific oysters of all size classes were already present near Texel. Near Ameland the development could be followed from the first observed settlement. On dense reefs each square metre may contain more than 500 adult Pacific oysters, weighing more than 100 kg per m² fresh weigh

Multiscale analysis of masonry vaults coupling shell elements to 3D-Cauchy continuum

This study adopts an enhanced multiscale approach to investigate the effects of the damaging process on the structural behavior of masonry vaults with regular texture, in view of their safety assessment. The model, recently developed by the authors, links two different structural models at macro and microscale, exploiting the advantages of each formulation. At the macroscopic level a homogeneous Mindlin-Reissner shell is modeled and its constitutive response is derived by the detailed analysis of a three-dimensional (3D) masonry Unit Cell (UC) studied at microlevel. The UC is considered as the assembly of elastic bricks and damage-plastic zerothickness interfaces, representative of both mortar and mortar-unit interaction, thus accounting for the actual geometry, arrangement and constitutive response of each constituent material. A Transformation Field Analysis procedure is used to link the two scales, speeding up the numerical simulations. Structural response of a masonry vault under differential settlements is investigated, determining its load-bearing capacity and the damaging path evolving in the structure up to collapse. The reliability of the results is proved by comparison with outcomes derived by detailed micromechanical analysis, interpreting and arguing similarities and differences. © 2023, Association of American Publishers. All rights reserved

Faba bean (Vicia faba minor) and pea seeds (Pisum sativum) as protein sources in lactating ewes' diets.

18 Massese lactating ewes, divided into 3 homogeneous groups for parity and milk yield, were used to evaluate the replacement effects of soybean meal by Faba bean (Vicia faba minor) and Pea (Pisum sativum) seeds. During a 70 days trial (beginning after weaning: 30±1.5 days after lambing) animals were fed three isonitrogenous and isocaloric diets. Each diet was characterised by the presence of only one protein feed. The diets consisted of alfalfa hay (1.1 kg/head/d) and a decreasing amount of mixed feed (from 1.1 to 0.7 kg/head/d) to fit animals' requirements. Milk yield, milk chemical composition, animals live weight and BCS, health state and hematochemical parameters were regularly monitored. No diets palatability problems were detected. No significant differences resulted for live weight, BCS, milk yield and milk chemical composition, except for milk protein: higher for faba bean (6.54%) and soybean (6.39%) respect pea (5.66%) diets, P<0.05. No differences resulted for blood parameters too and no clinical signs of illness were observed. Therefore faba bean and pea seeds seem to be able to replace the soybean well

Apparent digestibility of three diets in the Amiata breed donkey during lactation

The aim of the trial was to evaluate the apparent digestibility of three isonitrogenous and isocaloric diets for lactating donkeys: a diet with 8 kg of hay and 1.5 kg of commercial flaked mixed feed (CM) (Diet 1); a diet with 7 kg of hay and a 2.2 kg of CM (Diet 2) and a diet with 7 kg of hay, 1.5 kg of CM, 200 ml of corn oil and 0.2 kg of soybean meal (Diet 3). Four pluriparous donkeys (309±12 kg BW) at approximately 2-4 months of lactation were used. The trial was conducted according to a 3x3 Latin Square design with 1 or 2 subject per each cell. Feed and faeces samples were analysed for DM, OM, CP, EE, CF, NDF, ADF and gross energy. Acid insoluble ash was used as marker to calculate the apparent digestibility. The apparent digestibility of the main dietary components showed not significant differences among the three diets but generally they were lower in Diet 3. DM intakes of every diet exceeded the esti- mated energy requirement, whereas protein requirements were not significantly satisfied by Diet 1

Multiscale Finite Element Modeling Linking Shell Elements to 3D Continuum

The present paper investigates the response of masonry structural elements with periodic texture adopting an advanced multiscale finite element model, coupling different formualations at the two selected scales of analysis. At the macroscopic structural level, a homogeneous thick shell is considered and its constitutive response is derived by the detailed analysis of the masonry repetitive Unit Cell (UC), analyzed at the microlevel in the framework of the three-dimensional (3D) Cauchy continuum. The UC is formed by the assembly of elastic bricks and nonlinear mortar joints, modeled as zero-thickness interfaces. The Transformation Field Analysis procedure is invoked to address the nonlinear homogenization problem of the regular masonry. The performance of the model in reproducing various masonry textures is explored by referring to an experimentally tested pointed vault under different profiles of prescribed differential settlements. The structural behavior of the vault is studied in terms of global load-displacement curves and damaging patterns and the numerical results are compared with those recovered by detailed micromechanical analyses and experimental evidences