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Wildfires have increased in the last years and, when caused by intentional illegal burnings, are frequently run out of control. Wildfire has been pointed out as an important source of polycyclic aromatic hydrocarbons (PAHs) and trace elements (TEs) - such as, As, Ni, and Pb - to environmental compartments, and thus may pose a risk to human health and to the ecosystem. In 2020, the Brazilian biome, Pantanal, faced the largest losses by wildfires in the last 22 years. Ashes from the topsoil layer in Pantanal were collected after these wildfires at 20 sites divided into the sediment, forest, PF, PS, and degraded sites. Toxicity and associated risks for human health were also evaluated. The areas highly impacted by wildfires and by artisanal gold mining activities showed higher concentrations for TEs and PAHs than the protected areas. Pb varied from 8 ± 4 to 224 ± 81 mg kgThe online version contains supplementary material available at 10.1007/s11869-022-01248-2.

The deterioration of water quality worldwide is a serious environmental problem. Water managers still need operational tools to assess water issues and to inform water planning and decision-making. The aim of this article is to propose a 3-step methodological framework for assessing water pollution problems by combining a conceptual modeling tool (DPSIR) with the development of a quantitative model (Multi-Criteria Decision Model). This contribution provides a practical and flexible evaluation tool for conducting an integrated assessment of eutrophication and agrochemicals delivered to groundwater-dependent shallow lakes. It lays out action guidelines for decision-making environmental managers within the context of intermediate cities in developing countries. Forty-one indicators were identified to characterize the D-P-S-I compartments and for the multi-criteria model conceptualization. In this work, response options analysis consisted of evaluating and choosing water management instruments via a decision support tool. Two lake watersheds located in the peri-urban of two middle-size cities, in Argentina, were chosen to illustrate this methodological approach. The ensuing results allowed establishing a ranking of areas to prioritize, identifying a criteria and sub-criteria to focus on in order to set out action guidelines to minimize water pollution and eutrophication. These action guidelines are urgently needed in emerging countries, where financial, human resources and infrastructure are limited. The scarcity of such causes important implications regarding policy solutions for environmental issues. The implemented decision support tool in both lake watersheds provided a common basis for the understanding of the ongoing water pollution problems and a quantitative ranking (i.e., decision scores) for defining specific actions (responses) for human-induced stresses on such natural systems.

Study design Multicentre cross-sectional study. Objective The objective of this study is to evaluate prevalence, location and characteristics of pain in hospital inpatients people with spinal cord injury (SCI). Setting Ten Italian rehabilitation centres specialized in spinal injury care, where inpatients are admitted both after the acute lesion and for late complications (time since injury, median [IQR]: 0.8 [0.2-8.2] years). Methods All the persons were submitted to AIS scale assessment [1] and modified Ashworth scale [2]; personal data and anamnesis were recorded; any pain within 1 week was investigated and the International Spinal Cord Injury Pain Basic Data Set (ISCIPBDS) Italian version [3] was administered by physicians expert in type of pain definition. Results Of 385 included persons, 275 (72%) suffered pain, with the score value median [IQR]: 6 [4-8]. The worst pain of the person was nociceptive in 52% and neuropathic in 48% of the cases; 46% of nociceptive pain was located in the neck-shoulder region, whereas 67% of neuropathic pain was located in the sublesional part of the body. In 48% of the whole population, spasticity was observed but only 74% of them had pain. Being old and female are associated with high pain development, OR (95% CI): 1.24 (1.01-1.04) and 1.83 (1.05-3.20), respectively. Conclusions A high prevalence of pain is confirmed in persons with SCI, with both nociceptive and neuropathic pain characteristics. Only old age and female sex resulted as variables highly associated with pain.

Reinforced concrete structural walls (RCSWs) are one of the most efficient lateral force-resisting systems used in buildings, providing sufficient strength, stiffness, and deformation capacities to withstand the forces generated during earthquake ground motions. Identifying the failure mode of the RCSWs is a critical task that can assist engineers and designers in choosing appropriate retrofitting solutions. This study evaluates the efficiency of three ensemble deep neural network models, including the model averaging ensemble, weighted average ensemble, and integrated stacking ensemble for predicting the failure mode of the RCSWs. The ensemble deep neural network models are compared against previous studies that used traditional well-known ensemble models (AdaBoost, XGBoost, LightGBM, CatBoost) and traditional machine learning methods (Naïve Bayes, K-Nearest Neighbors, Decision Tree, and Random Forest). The weighted average ensemble model is proposed as the best-suited prediction model for identifying the failure mode since it has the highest accuracy, precision, and recall among the alternative models. In addition, since complex and advanced machine learning-based models are commonly referred to as black-box, the SHapley Additive exPlanation method is also used to interpret the model workflow and illustrate the importance and contribution of the components that impact determining the failure mode of the RCSWs.

Purpose With an increase in the number of adapted sports, the need to monitor sports performance in people with different abilities has grown. Indeed, a thorough evaluation of the sports gesture could prevent the occurrence of injuries, enable a continuous performance assessment, and allow to verify the compliance of the requirements for the competitions. Gesture kinematics provides an assessment of performance, while the muscle activities reveal the underlying strategies adopted by each athlete. In this context, we propose an instrumented evaluation to assess performance in Para-powerlifting. Our goal is to define and test a setup and a protocol to quantitatively assess the execution of bench press exercise in athletes with different abilities. Methods We recruited an unimpaired athlete and three Paralympic athletes. They were requested to execute the bench press exercise while we recorded muscle activity and kinematic data from the upper body. We investigated the sport gesture by extracting parameters describing coordination, symmetry, and synchronism between arms, and motor variability while repeating the gesture. Results Paralympic athletes performed the gestures with higher coordination between arms and low variability across repetitions compared to the unimpaired athlete, who was not at the Olympic level. All participants obtained similar kinematic performance by adopting different muscle strategies. Conclusions This study is a proof of concept that the instrumented evaluation proposed here can allow to conduct a complete assessment of the bench press exercise, in terms of kinematics, muscle activity and performance in athletes with different abilities.

This work focuses on the study of the influence of microshrinkage cavities on the plastic deformation and fracture of ferritic ductile iron. Cast samples were especially developed to include dispersed microshrinkage. Tensile testing and digital image correlation analysis are employed to assess the influence of dispersed microshrinkage cavities as preferential sites for crack initiation and propagation under uniaxial static load. The results show that small microshrinkage cavities of up to 3.5 times the area of graphite nodules are not linked to the initiation and propagation of cracks in ductile iron. The methodology developed in this work becomes useful to evaluate the influence of size, distribution, and morphology of different microshrinkage defects on the damage evolution during tensile loading.

The evaluation of sky characteristics plays a fundamental role for many astrophysical experiments and ground-based observations. In solar physics, the main requirement for such observations is a very low sky brightness value, less than $10^{-6}$ 10 − 6 of the solar disk brightness ($\mathrm{B}_{\odot }$ B ⊙ ). Few places match such a requirement for ground-based, out-of-eclipse coronagraphic measurements. One of these places is, for instance, the Mauna Loa Observatory ($\approx 3400~\mbox{m}$ ≈ 3400 m a.s.l.). Another candidate coronagraphic site is the Dome C plateau in Antarctica. In this article, we show the first results of the sky brightness measurements at Dome C with the Extreme Solar Coronagraphy Antarctic Program Experiment (ESCAPE) at the Italian–French Concordia Station, on Dome C, Antarctica ($\approx 3300~\mbox{m}$ ≈ 3300 m a.s.l.) during the 34th and 35th summer Campaigns of the Italian Piano Nazionale Ricerche Antartiche (PNRA). The sky brightness measurements were carried out with the internally occulted Antarctic coronagraph AntarctiCor. In optimal atmospheric conditions the sky brightness of Dome C has reached values of the order of 1.0 – $0.7 \times 10^{-6}~\mathrm{B}_{\odot }$ 0.7 × 10 − 6 B ⊙ .

Three medium-carbon, high-silicon cast steels with different alloy contents were austempered at 330 °C for different holding times in order to obtain carbide-free bainitic microstructures. Aiming at evaluating the influence of holding time and microstructural features on strength and ductility, tensile properties were measured for each steel at selected austempering times. The results obtained indicate that it is possible to adjust holding time in order to obtain the best strength/ductility combination at determined austempering temperature. Moreover, it has been shown that the mechanical stability of retained austenite is the key factor in controlling tensile performance. Short austempering times result in low carbon enrichment of the austenite (low stability) and promote higher ultimate tensile strength and lower ductility. For longer austempering times, steels present a slight decrease in ultimate tensile strength but a marked increase in ductility. This work shows that it is possible to obtain cast steels with ultimate tensile strength of 1682 MPa, yield strength of 1493 MPa and total elongation of 12.5% by means of bainitic reaction. This strength/ductility combination and others reported in this study are remarkable for cast steels.

Solar abundances have been historically assumed to be representative of cosmic abundances. However, our knowledge of the solar abundance of helium, the second most abundant element, relies mainly on models1 and indirect measurements through helioseismic observations2, because actual measurements of helium in the solar atmosphere are very scarce. Helium cannot be directly measured in the photosphere because of its high first ionization potential, and measurements of its abundance in the inner corona have been sporadic3,4. In this Letter, we present simultaneous global images of the helium (out to a heliocentric distance of 3R⊙ (solar radii)) and hydrogen emission in the solar corona during the minimum of solar activity of cycle 23 and directly derive the helium abundance in the streamer region and surrounding corona (out to 2.2R⊙). The morphology of the He+ corona is markedly different from that of the H corona, owing to significant spatial variations in helium abundance. The observations show that the helium abundance is shaped according to and modulated by the structure of the large-scale coronal magnetic field and that helium is almost completely depleted in the equatorial regions during the quiet Sun. This measurement provides a trace back to the coronal source of the anomalously slow solar wind observed in the heliosphere at the Sun–Earth Lagrangian point L1 in 2009, during the exceptionally long-lasting minimum of solar activity cycle 23. Global images of helium and hydrogen emission are used to directly derive the helium abundance out to 2.2R⊙. The helium abundance is shaped by the large-scale coronal magnetic field. Helium is almost completely depleted near the equator in the quiet Sun.

This manuscript summarizes recent investigation of the authors into the solidification and shrinkage defect formation of ductile and compacted graphite cast irons. The study makes use of the DAAS (direct austempering after solidification) technique, developed earlier by some of the authors, to reveal the solidification grains. In addition, color metallography is used to reveal the microsegregation pattern. The formation of shrinkage defects is related to both the solidification macrostructure and the microsegregation pattern. The examination of the macrostructure shows that large solidification grains, composed by dendritic austenite and graphite, characterize the solidification of compacted graphite irons of carbon equivalent values ranging from hypoeutectic to hypereutectic. Similar results are observed for ductile iron, but in this case, the hypereutectic irons display a finer macrostructure. The characteristics of the primary austenite dendrites are revealed by the microsegregation pattern, which is exposed by the color etching reagent. This pattern also clarifies the nature of the interaction between the growing austenite and the compact and spheroidal graphite particles. The microshrinkage cavities in both ductile and compacted graphite irons form at the interior of the austenite grains, where fluid feeding cannot compensate the contraction of the last-to-freeze portions of the melt. Schematics of the solidification of ductile and compacted irons are proposed, accounting for the experimental observations.

Three main stages in the development of groundwater pollution assessment since the 1970s are described. The first steps involved aquifer vulnerability assessment. In the second stage (from the late 1980s), three methodological approaches to risk assessment were developed. The latest stage (from the 1990s) has involved new technologies and approaches. At present, all three stages coexist, and their advantages and disadvantages are discussed. Experience highlights the need to account for the social vulnerability in risk assessment, particularly with respect to large cities in developing countries. Assessing groundwater pollution risk through an integrated approach appears to be the greatest challenge.

There is a current discussion concerning the austenite grains of lamellar graphite irons and its growth at different carbon equivalent contents. The term “grain” is often employed to refer not only to the primary austenite, but also to the colonies or cells formed during the eutectic solidification. This investigation applies advanced experimental methods to study the solidification of lamellar graphite iron. A better understanding of the solidification process should lead to the design of better casting procedures. Samples of lamellar graphite iron were cast and directly austempered after solidification in order to reveal their solidification macrostructure. A typical ingot structure was found, with a narrow columnar-to-equiaxed transition. Electron backscatter diffraction technique was applied to confirm these macroscopic observations. Color etching was employed to determine the size of eutectic colonies at the columnar and equiaxed regions. The EBSD results confirm previous proposals, revealing that the solidification grains result from the growth of austenite dendrites. These grains include several eutectic colonies or cells inside, all these colonies or cells having the same crystalline orientation as the primary austenite dendrite. An analysis of the critical gradient for columnar-to-equiaxed transition could be developed. The size of the eutectic colonies at the columnar zone was found to be smaller than the size of the eutectic colonies at the equiaxed zone. Besides, the size of equiaxed grains strongly decreased with the increase in cooling rate, while no evident differences were obtained when the size of the columnar grains was measured.

Low cycle fatigue life of high-strength reinforcing steel bars (ASTM A706 Grade 80), using photogrammetry by RGB methodology is evaluated. Fatigue tests are performed on specimens under constant axial displacement with total strain amplitudes ranging from 0.01 to 0.05. The experimental observations indicate that buckling of high-strength reinforcing bars results in a damaging degradation of their fatigue life performance as the slenderness ratio increases, including an early rebar failure as the total strain amplitude increases since it achieves the plastic range faster. In addition to this, the results show that the ratio of the ultimate tensile strength to yield strength satisfies the minimum of 1.25 specified in ASTM A706 for reinforcement. On the other hand, the RGB methodology indicates that the axial strains measured by photogrammetry provide more accurate data since the registered results by the traditional experimental setup do not detect second-order effects, such as slippage or lengthening of the specimens within the clamps. Moreover, the RGB filter is faster than digital image correlation (DIC) because the RGB methodology requires a fewer computational cost than DIC algorithms. The RGB methodology allows to reduce the total strain amplitude up to 45% compared to the results obtained by the traditional setup. Finally, models relating total strain amplitude with half-cycles to failure and total strain amplitude with total energy dissipated for multiple slenderness ratios (L/d of 5, 10, and 15) are obtained.

This paper presents information on development, calibration, and validation of three companion macroscopic modeling approaches for nonlinear analysis of reinforced concrete (RC) structural walls, including: (1) the baseline two-dimensional two-node formulation of the Shear–Flexure-Interaction Multiple-Vertical-Line-Element-Model (SFI-MVLEM), (2) extension of the baseline SFI-MVLEM for modeling of squat walls (SFI-MVLEM-SQ), and (3) extension of the baseline SFI-MVLEM to a three-dimensional four-node element for simulation of non-planar RC walls under multi-directional loading (SFI-MVLEM-3D). The models are implemented in the computational platform OpenSees. Models presented are calibrated and validated against experimental results obtained from tests on RC wall specimens that cover a wide range of physical and behavioral characteristics, including: (1) one slender, two moderately-slender and one medium-rise planar RC walls tested under in-plane loading used for validation of the baseline SFI-MVLEM, (2) three squat planar RC wall specimens tested under in-plane loading used for validation of the SFI-MVLEM-SQ, and (3) one T-shaped and one U-shaped RC wall specimen tested under unidirectional and multi-directional loading, respectively, used for validation of SFI-MVLEM-3D. The comprehensive comparisons between analytically-obtained and experimentally-measured wall responses suggest that the analytical models proposed can accurately simulate both global and local wall responses, within their range of applicability. The models capture load–displacement response features of the walls, including lateral load capacity, lateral stiffness, cyclic stiffness degradation, and pinching characteristics, as well as nonlinear shear deformations and their coupling with flexural deformations during cyclic loading. Comparisons between experimental and analytical results at local response levels suggest that the models can also replicate distributions and magnitudes of wall vertical strains and curvatures at various locations. Overall, the analytical models presented provide robust and reliable tools for nonlinear analysis of RC walls, with a wide range of applicability.

This work investigates the size and morphology of the primary austenite grains present in lamellar graphite cast iron. Samples of lamellar graphite iron were cast and austempered during the post-solidification cooling stage in order to preserve part of the original austenite at room temperature. Electron backscatter diffraction technique was applied to reveal the regions of different crystalline orientation of the austenite. The eutectic colonies and the last-to-freeze areas were also examined by color etching of the same regions previously analyzed by electron backscatter diffraction. The results reveal that the solidification units of lamellar graphite iron are formed by austenite grains that include several eutectic colonies inside, all of which have the same crystalline orientation as the primary austenite grain. For all the samples studied, it can be confirmed that there are no eutectic colonies with a different crystalline orientation than that of the primary austenite dendrites. Fil: López, Marcos Gabriel. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mar del Plata. Instituto de Investigaciones en Ciencia y Tecnología de Materiales. Universidad Nacional de Mar del Plata. Facultad de Ingeniería. Instituto de Investigaciones en Ciencia y Tecnología de Materiales; Argentina Fil: Brewer, Luke N.. University Of Alabama; Estados Unidos Fil: Massone, Juan Miguel. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mar del Plata. Instituto de Investigaciones en Ciencia y Tecnología de Materiales. Universidad Nacional de Mar del Plata. Facultad de Ingeniería. Instituto de Investigaciones en Ciencia y Tecnología de Materiales; Argentina Fil: Boeri, Roberto Enrique. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mar del Plata. Instituto de Investigaciones en Ciencia y Tecnología de Materiales. Universidad Nacional de Mar del Plata. Facultad de Ingeniería. Instituto de Investigaciones en Ciencia y Tecnología de Materiales; Argentina

Investigation were carried out targeting distribution and source apportioning of hydrocarbons in surface sediments from shallow to deep waters in the Campos Basin, one of the most important oil-producing provinces in Brazil. The observed levels of aliphatic (≤ 124 μg g−1) and polycyclic aromatic hydrocarbons (PAHs ≤ 599 ng g−1) are lower than those considered relevant for environmental risk to the benthic habitats. Higher median concentrations of aliphatic hydrocarbons (8.49 μg g−1) and PAHs (84.8 ng g−1) in the middle slope sediments (700–1000-m water depths) showed the influence of hydrodynamics upon hydrocarbon accumulation in the sediments. Diagnostic ratios and conventional statistical analysis applied to hydrocarbon data produced insufficient information on the contribution of different sources. These traditional approaches do not consider the potential changes affecting source assignment and therefore cannot deal with the uncertainties. The fuzzy logic applied as an alternative method for data treatment successfully incorporated the uncertainties in the differentiation between petrogenic and pyrolytic sources, including those due to degradation. Moreover, by using fuzzy logic, it was possible to identify that water circulation patterns, mass transport, deposition, and degradation processes are more relevant factors in determining hydrocarbon composition than source proximity.

This work evaluates the factors affecting the presence of organochlorine pesticides in Pampeano aquifer in the Quequén Grande River watershed, Buenos Aires Province, Argentina. Eighteen sampling sites were selected in order to have representatives of different type of wells and types of soil. Among the analyzed compounds, endosulfan showed the highest concentrations(4.75 ng l−1 mean), which could be related to use in the recent past. Others important pesticides groups detected were HCHs (1.1 ng l−1 mean) and heptachlors (2.17 ng l−1mean). The analysis of the results show that the thickness of theunsaturated zone is the main factor related to the concentrations of pesticides and there were no differences according to wells or soil types. Although agricultural use of most OCPs has been banned in Argentina from more than 30 years ago, their residues are still detected in groundwater of the region, indicating their high persistence. Fil: Grondona, Sebastian. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mar del Plata. Instituto de Investigaciones Marinas y Costeras. Universidad Nacional de Mar del Plata. Facultad de Ciencias Exactas y Naturales. Instituto de Investigaciones Marinas y Costeras; Argentina. Universidad Nacional de Mar del Plata. Facultad de Ciencias Exactas y Naturales. Instituto de Geología de Costas y del Cuaternario. Provincia de Buenos Aires. Gobernación. Comisión de Investigaciones Científicas. Instituto de Geología de Costas y del Cuaternario; Argentina Fil: Gonzalez, Mariana. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mar del Plata. Instituto de Investigaciones Marinas y Costeras. Universidad Nacional de Mar del Plata. Facultad de Ciencias Exactas y Naturales. Instituto de Investigaciones Marinas y Costeras; Argentina Fil: Martinez, Daniel Emilio. Universidad Nacional de Mar del Plata. Facultad de Ciencias Exactas y Naturales. Instituto de Geología de Costas y del Cuaternario. Provincia de Buenos Aires. Gobernación. Comisión de Investigaciones Científicas. Instituto de Geología de Costas y del Cuaternario; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mar del Plata. Instituto de Investigaciones Marinas y Costeras. Universidad Nacional de Mar del Plata. Facultad de Ciencias Exactas y Naturales. Instituto de Investigaciones Marinas y Costeras; Argentina Fil: Massone, Hector Enrique. Universidad Nacional de Mar del Plata. Facultad de Ciencias Exactas y Naturales. Instituto de Geología de Costas y del Cuaternario. Provincia de Buenos Aires. Gobernación. Comisión de Investigaciones Científicas. Instituto de Geología de Costas y del Cuaternario; Argentina Fil: Miglioranza, Karina Silvia Beatriz. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mar del Plata. Instituto de Investigaciones Marinas y Costeras. Universidad Nacional de Mar del Plata. Facultad de Ciencias Exactas y Naturales. Instituto de Investigaciones Marinas y Costeras; Argentina

Slender RC walls are often used in Chile and commonly, due to architectural constraint, the length of walls increases (setback) between floors designated for parking space and upper floors. These types of elements are commonly called flag walls. In this research, the behavior of slender reinforced concrete walls with a constant axial load and a cyclic lateral displacement is numerically studied, in order to compare the results obtained with previous tests. Two different model alternatives are considered: a finite element model and a strut-and-tie model. The selected models allow understanding local response, as well as, distribution of internal forces, which is also relevant information for wall design and detailing. The studied finite element model, based on quadrilateral elements with 3 degrees of freedom per node (2 translational and 1 rotation) and a model of smeared reinforced concrete material based on a rotating angle approach, is able to correctly capture the global response, showing the capacity, degradation and failure mode obtained in the tests. On the other hand, a parametric analysis is performed for models of walls with higher aspect ratio (tall buildings) with small discontinuities, showing a larger impact in deformation capacity due to the high concentration of damage at the discontinuity. These results indicate that in 25-floor high walls (or taller) a reduction of displacement capacity of 40% for discontinuities located at the first floor could be observed. In addition, by incorporating the effect of the slabs into the model, the results indicate that a pure flexure model is an adequate and sufficient tool for analysis. Finally, a strut-and-tie model is also proposed for each direction of the lateral load, whose results are compared with the estimated load calculated with the strains measured by photogrammetry. The considered strut-and-tie model for the case of lateral load with tension in the continuous wall boundary is similar to the wall without discontinuity, which is consistent with the measured strains. For both lateral loading directions, the estimated forces of the horizontally distributed bars and boundary reinforcements are consistent with photogrammetry in the lower zone of the wall, where cracking is relevant. The strut-and-tie model also adequately interprets the effect of the discontinuous bar on the discontinuous boundary of the wall. All these results can help designing and detailing flag walls.

In this article, a simple and accurate quadrilateral thin flat layered shell element formulation for the nonlinear analysis of reinforced concrete (RC) wall systems under static and cycling loads is presented. The 4 node shell element, with 6 degree of freedom (DOF) per node (3 displacements and 3 rotations) is created by superposing the quadrilateral layered membrane element with drilling degrees of freedom (12 DOF, 2 displacement and 1 rotation per node) developed by Rojas et al. (Eng Struct 124:521–538, 2016), and the Discrete Kirchhoff Quadrilateral Element (12 DOF, 1 displacement and 2 rotations) formulated by Batoz and Tahar (Int J Numer Methods Eng 18(11):1655–1677, 1982), to model the in-plane and the out of plane bending behavior of the shell element, respectively. In addition, to model the complex behavior and coupling of the axial, flexural and shear behavior, observed in complex RC wall structures, the transversal section of the shell element consists of a layered system of fully bonded, smeared steel reinforcement and smeared orthotropic concrete material with the rotating angle formulation. The formulation used a tangent stiffness matrix approach, which include the coupling of membrane and bending effects. For verification, the shell element formulation is used to model a set of experimental results for T-shaped RC walls that are available in the literature. The proposed element is robust, simple to implement, and it can predict the global results (load vs. displacement and maximum capacity) and also the local behavior (vertical strain at the base level along the web and the flange) observed in RC wall structures.

RC structural slender walls under large seismic excitation are expected to reach base moment capacity mainly affected by the first vibration mode. However, the base shear could be affected by higher modes once yielding in flexure has occurred, which might result in base shear underestimation in linear design. In this work, an experimental program is carried out on five RC rectangular walls 1:10 scaled. All five specimens considered irregularities at base, common in construction and one specimen did not consider shear reinforcement or boundary detailing. Tests are carried on a unidirectional shaking table and excitation is based on two Chile earthquake records with different intensities. Damage is concentrated at the wall base for all specimens; primary due to flexure with some participation of shear. For one of the records an average amplification of 1.3 is obtained, and a decrease in height of the resultant equivalent lateral force closes to 0.4 hw. By increasing the intensity of the input record, amplification grows to an average of 1.7, while it decreases drastically when subjected to input records with low frequency content. No significant difference is observed in shear amplification in specimens with a base central opening, nor with setback, even though the cracking and failure mode was different for such specimens. Ductility demand shows no correlation when two different earthquakes are considered, whereas the frequency content and Arias intensity (Ia) of the input record directly affected the shear amplification.

Health education is fundamental in the management of RA patients. This study explored patient needs for educational material appropriate for RA patients in our region through a website. This study includes seven focus groups and semi-structured interviews across 4 countries (Argentina, Chile, Colombia, and Mexico) with 71 RA patients. Transcripts were analyzed by anthropologists using qualitative analysis (QA), resulting in themes and subthemes to be developed. Five themes and over 50 subthemes of interest were identified by patients. Grouped into categories as follows: (1) knowing the disease, (2) living with arthritis, (3) treatment and therapies for RA, (4) psychosocial support, and (5) information for families. A response was written by the team in plain Spanish on patient subthemes of interest including additional areas that the team considered relevant. Three videos for YouTube were produced: on patient-doctor relationships, patients at work, and home and at the clinic. Illustrations in a comic book format on RA diagnosis were created. The educational site on RA of PANLAR can be found at htpp://artritisreumatoide.cl. This project accomplished a comprehensive list of RA patient interests, revealing the complex relationship between the information on the disease, the experience of a chronic disease, and the way in which patients approach, conceive, and manage their disease. We expect to gather information on how the website will be used in the future for patients and their families and maintain and improve the website as well as adapt its content to different socioeconomic realities.

This work deals with the piston failures found in diesel engines functioning in light trucks. The failure was a hole inside the bowl located at the top of the piston, which is the combustion chamber of the engine. This hole progressed and finds its way out between the second and third rings. The operational characteristics of the engine were analyzed in order to elucidate the probable acting failure mechanisms. For the evaluation, obviously were assessed the damaged pistons but also pistons of the same engine without the mentioned failure and a new piston. Different studies and measurements were carried out such as microstructural morphologies and transformations, hardness, fracture surface analysis and chemical composition. The piston design, the material used and the operational conditions (thermal and mechanical) were studied with the purpose of determining the failure origin. It was concluded that thermomechanical fatigue along with some degree of degradation suffered by the material is responsible of the reported failure. Fil: Caldera, Martin. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mar del Plata. Instituto de Investigaciones en Ciencia y Tecnología de Materiales. Universidad Nacional de Mar del Plata. Facultad de Ingeniería. Instituto de Investigaciones en Ciencia y Tecnología de Materiales; Argentina Fil: Massone, Juan Miguel. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mar del Plata. Instituto de Investigaciones en Ciencia y Tecnología de Materiales. Universidad Nacional de Mar del Plata. Facultad de Ingeniería. Instituto de Investigaciones en Ciencia y Tecnología de Materiales; Argentina Fil: Martinez, Ricardo Antonio. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mar del Plata. Instituto de Investigaciones en Ciencia y Tecnología de Materiales. Universidad Nacional de Mar del Plata. Facultad de Ingeniería. Instituto de Investigaciones en Ciencia y Tecnología de Materiales; Argentina

A simple yet effective constitutive model-referred to as the “Fixed Strut Angle Model” (FSAM)-is presented in this paper for simulating the nonlinear axial/shear behavior of reinforced concrete membrane (panel) elements subjected to generalized and reversed cyclic loading conditions. In the formulation of the FSAM, normal stresses in cracked concrete are calculated along fixed crack (strut) directions. Shear stresses developing along crack surfaces, which are calculated using a simple friction-based constitutive relationship, are superimposed with the concrete stresses along the struts, for obtaining the total stress field in concrete. Model predictions were compared with panel tests results available in the literature, at various global and local response levels. The model was demonstrated to reasonably capture the overall response characteristics of reinforced concrete panels, including hysteretic shear stress vs. strain behavior, shear stress capacity, hysteretic shear stiffness attributes, ductility, pinching behavior, governing failure mode, principal strain and stress directions, and local deformations.

The aim of this study was to contribute to the understanding of the hydrogeological system of the Argentine Patagonia Extra-Andina region, focused on the Atlantic coastal area at 46° south latitude. The hydrogeochemical aspects of this aquifer system were taken into consideration for this purpose. The database includes 193 chemical analyses of major ions obtained through standard laboratory methods. A statistical analysis of the data, as well as the realization of hydrochemical models using PHREEQC software, was performed. The regional groundwater flows from west to east, with the recharge water being a sodium-chloride-bicarbonate type, and the discharge of water is typified as a sodium-sulfate-chloride type. The hydrogeochemical evolution of the aquifer shows a general augmentation of salinity and major ions in the groundwater-flow path, except for HCO3−. Inverse hydrochemical modeling showed that gypsum dissolution with calcite precipitation, Ca2+/Na+ and Mg2+/Na+ ionic exchange, and dedolomitization are the main processes along the groundwater flow pathway. Fil: Baumann, Guilermo Osvaldo. Municipio de Rio Gallegos; Argentina Fil: Vital, Mélanie. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mar del Plata. Instituto de Investigaciones Marinas y Costeras. Universidad Nacional de Mar del Plata. Facultad de Ciencias Exactas y Naturales. Instituto de Investigaciones Marinas y Costeras; Argentina Fil: Glok Galli, Melisa. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mar del Plata. Instituto de Investigaciones Marinas y Costeras. Universidad Nacional de Mar del Plata. Facultad de Ciencias Exactas y Naturales. Instituto de Investigaciones Marinas y Costeras; Argentina Fil: Grondona, Sebastián. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mar del Plata. Instituto de Investigaciones Marinas y Costeras. Universidad Nacional de Mar del Plata. Facultad de Ciencias Exactas y Naturales. Instituto de Investigaciones Marinas y Costeras; Argentina Fil: Massone, Hector Enrique. Universidad Nacional de Mar del Plata; Argentina Fil: Martinez, Daniel Emilio. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mar del Plata. Instituto de Investigaciones Marinas y Costeras. Universidad Nacional de Mar del Plata. Facultad de Ciencias Exactas y Naturales. Instituto de Investigaciones Marinas y Costeras; Argentina. Universidad Nacional de Mar del Plata. Facultad de Ciencias Exactas y Naturales. Instituto de Geología de Costas y del Cuaternario. Provincia de Buenos Aires. Gobernación. Comisión de Investigaciones Científicas. Instituto de Geología de Costas y del Cuaternario; Argentina

Reinforcing bars removed from structural walls that belonged to a damaged building during the 2010 earthquake in Chile are studied under low-cycle fatigue testing. Damage of such walls was characterized by concrete crushing and boundary longitudinal reinforcement buckling. Reinforcement bars are selected from damaged areas, including reinforcement with and without visible buckling. Cyclic load tests are performed with constant strain amplitude in the plastic range (3% and 5%), using an aspect ratio of 20. Fatigue life loss is observed in specimens from reinforcement bars with visible buckling damage with up to 15 cycles less than unaltered bars (3% amplitude tests), and with a fatigue life reduction of at least 40% for bars with and without observed buckling compared to unaltered bars, which indicates a low remaining fatigue capacity. A strain amplitude model also indicates that for a given number of cycles to fatigue failure, the strain amplitude reduces to 36% when comparing bars in buckled zone to unaltered bars. The seismic displacement demand on the building is of about 5 cycles of large amplitude and considering that some longitudinal bars fractured, it indicates that they could have reached 5% strain amplitude.

The Hough transform is a standard pattern recognition technique introduced between the 1960s and the 1970s for the detection of straight lines, circles, and ellipses with several applications including the detection of symmetries in images. Recently, based on algebraic geometry arguments, the procedure has been extended to the automated recognition of special classes of algebraic plane curves. This allows us to detect curves of symmetry present in images, that is, curves that recognize midpoints maps of various shapes extracted by an ad hoc symmetry algorithm, here proposed. Further, in the case of straight lines, the detection of lines of symmetry allows us, by a pre-processing step of the image, to improve the efficiency of the recognition algorithm on which the Hough transform technique is founded, without loss of generality and additional computational costs.