New analysis method for continuous base-flow and availability of water resources based on Parallel Linear Reservoir models

Water flows in the hydrosphere through a tangled and tortuous labyrinth of ways that is the hydrological cycle. Flow separation models are an attempt to group such complexity of paths into a few components of flow and storage so as to reflect the overall behaviour of a basin. A new method of analysis and separation of flow components, based on equations of dynamic relations between Linear Reservoirs connected in Parallel (PLR models), is developed in this article. A synthesis of models based on mathematical filter equations is carried out in order to make comparisons with the proposed model. Reference is also made to the methodology of adjustment and calibration of the PLR models based on the recession curves of the real hydrographs. The models are tested with the continuous register of a basin located in the northeast of Spain. The simulations are carried out with two reservoir models (2R models), three reservoirs (3R models) and with a mathematical filter model to compare the results. With the results of the models, flow duration curves (FDCs) and storage duration curves (SDCs) were elaborated, thus allowing assessment of the origin of the water resources of the basin, a guarantee of their regulation and availability, the dynamic storage in the catchment, residence times and other features

A procedure for indirect and automatic measurement of prior austenite grain size in bainite/martensite microstructures

An alternative procedure for indirect and automatic measurement of the prior austenite grain size (PAGS) in bainite/martensite is proposed in this work. It consists in the determination of an effective grain size (EGS) by means of statistical post-processing of electron backscatter diffraction (EBSD) data. The algorithm developed for that purpose, which is available on-line, has been applied to simulated EBSD maps as well as to both a nanocrystalline bainitic steel and a commercial hot-rolled air-cooled steel with a granular bainitic microstructure. The new proposed method has been proven to be robust and results are in good agreement with conventional PAGS measurements. The added value of the procedure comes from its simplicity, as no parent reconstruction is involved during the process, and its suitability for low-magnification EBSD maps, thus allowing a large step-size and coverage of a substantially broader area of the sample than the previous methods reported.Spanish Ministry of Economy and Competitiveness for funding this research under the contract IPT-2012-0320-420000. L.M.-R. also acknowledges the Spanish Ministry of Economy and Competitiveness for financial support in the form of a PhD research grant (FPI-Ref. BES-2011-044186).Peer reviewe

Aplicación de nuevas técnicas de investigación biomecánica en cirugía de los tendones flexores

Con el objeto de investigar la tensión intratendinosa, la distribución de la carga y la orientación de las líneas de fuerza, a nivel de las suturas tendinosas, se proponen 2 métodos: fotoelasticidad y elementos finitos, basados en técnicas utilizadas en ingeniería mecánica. Obtenida previamente una probeta de resina epoxi, de comportamiento similar al tendón y propiedades fotoelásticas adecuadas para el estudio, se ha mecanizado según el método de sutura y sometido a tracción continua en el banco de carga de un polariscopio, constituyendo 3 grupos con 72 estudios cada uno. Todos los datos obtenidos fueron procesados con un programa para estudios,fotoelásticos utilizado por el Departamento de Mecánica y valorados estadísticamente con el Sigma. Posteriormente se ha realizado el mismo estudio mediante el método de elementos finitos utilizando el módulo Geostar del Cosmos/M v 1.61. La carga intratendinosa más alta y su distribución central se obtiene en los métodos de lazo (BUNNELL y KLEINERT). Por el contrario, los métodos en cuadro son menos isquemiantes, con menor carga y distribución periférica de la tensión, siendo el método de Kessler el que mejor orientación axial presenta. Proponemos el método de Kesslev, como técnica de elección biomecánicamente, en cirugía de los tendones flexores.Peer Reviewe

Hall-Petch strengthening of the constrained metallic binder in WC-Co cemented carbides: Experimental assessment by means of massive nanoindentation and statistical analysis

WC–Co cemented carbides are geometrically complex composites constituted for two interpenetrating networks of the constitutive ceramic and metal phases. Accordingly, assessment of microstructural effects on the local mechanical properties of each phase is a challenging task, especially for the metallic binder. In this work, it is attempted by combining massive nanoindentation, statistical analysis, and implementation of a thin film model for deconvolution of the intrinsic hardness and flow stress of the metallic phase. Plotting of yield stress values as a function of the binder mean free path results in a Hall-Petch strengthening relationship with a slope (ky) of 0.98 MPa m1/2. This value points out the effectiveness of WC–Co phase boundaries as strong obstacles to slip propagation; and thus, for toughening of the brittle phase (WC) by means of crack-bridging ductile (Co) reinforcement.Peer ReviewedPostprint (author's final draft

Evaluation of potential of high Si high C steel nanostructured bainite for wear and fatigue applications

The present study is concerned with the potential of high carbon, high silicon steel grades isothermally transformed to bainite at low temperature (<300 C). The first part gives an overview of the design principles, allowing very high strength and ductility to be achieved while minimising transformation duration. Wear and fatigue properties are then investigated for over 10 variants of such materials, manufactured in the laboratory or industrially. The results are discussed against published data. Tensile strengths above 2 GPa are routinely achieved, with, in one case, an exceptional and unprecedented total elongation of over 20%. Bainite plate thickness and retained austenite content are shown to be important factors in controlling the yield strength, though additional, non-negligible parameters remain to be quantified. Rolling-sliding wear performances are found to be exceptional, with as little as 1% of the specific wear rate of conventional 100Cr6 isothermally transformed to bainite. It is suggested that this results from the decomposition of retained austenite in the worn layer, which considerably increases hardness and presumably introduces compressive residual stresses. Fatigue performance was slightly improved over 100Cr6 for one of the two industrially produced materials but significantly lower otherwise. Factors controlling fatigue resistance require further investigations. © 2013 Institute of Materials, Minerals and Mining Published by Maney on behalf of the Institute.Peer Reviewe

Unravelling plant diversification: Intraspecific genetic differentiation in hybridizing Anacyclus species in the western Mediterranean Basin

Premise: The interfertile species Anacyclus clavatus, A. homogamos, and A. valentinus represent a plant complex coexisting in large anthropic areas of the western Mediterranean Basin with phenotypically mixed populations exhibiting a great floral variation. The goal of this study was to estimate the genetic identity of each species, to infer the role of hybridization in the observed phenotypic diversity, and to explore the effect of climate on the geographic distribution of species and genetic clusters. Methods: We used eight nuclear microsatellites to genotype 585 individuals from 31 populations of three Anacyclus species for population genetic analyses by using clustering algorithms based on Bayesian models and ordination methods. In addition, we used ecological niche models and niche overlap analyses for both the species and genetic clusters. We used an expanded data set, including 721 individuals from 129 populations for ecological niche models of the genetic clusters. Results: We found a clear correspondence between species and genetic clusters, except for A. clavatus that included up to three genetic clusters. We detected individuals with admixed genetic ancestry in A. clavatus and in mixed populations. Ecological niche models predicted similar distributions for species and genetic clusters. For the two specific genetic clusters of A. clavatus, ecological niche models predicted remarkably different areas. Conclusions: Gene flow between Anacyclus species likely explains phenotypic diversity in contact areas. In addition, we suggest that introgression could be involved in the origin of one of the two A. clavatus genetic clusters, which also showed ecological differentiationPID2019‐104135GB‐I00, PID2021‐124187NB‐I0

The sequential twinning-transformation induced plasticity effects in a thermomechanically processed high Mn austenitic steel

Different initial microstructures with various bimodal grain size distributions (BGSD) were produced in a high Mn austenitic steel through applying a predetermined set of thermomechanical processing cycles. The corresponding room temperature mechanical properties and the related strain hardening behaviors were assessed using tensile testing method. The results indicated that in the microstructure with high grain size bimodality, the length and amplitude of rapid hardening region was well higher than the others. This was attributed to its higher capability to a'-martensite formation. In addition, the threshold strain to initiate martensitic transformation was shifted to the lower one in the microstructure with higher bimodal grain size distribution. The latter was related to the lower arisen back stresses in the interior regions of the coarser grains. Furthermore, different transformation paths were identified as the BGSD changed. The austenite could directly transform to a'-martensite (¿a') in the microstructure with lower BGSD; in this case the a'-martensite mainly appeared at the intersections of deformation twins. In contrast, in microstructures with higher BGSD, the nucleation occurred at the intersections of e-martensite platelets. The co-existence of these transformation paths provided an extended transformation induced plasticity effect ending to a higher elongation to fracture in the course of deformation. In order to summarize the contribution of various strain hardening mechanisms, a deformation map was also constructed. Accordingly, the enhanced ductility/strength properties were attributed to the sequential operation of extended transformation induced plasticity and twinning induced plasticity effects.Peer ReviewedPostprint (author's final draft

Influence of testing mode on the fatigue behavior of <111> austenitic grain at the nanometric length scale for TRIP steels

Metastable austenitic stainless steels, and in particular the TRansformation Induced Plasticity steels, rely on a phase transformation from a ductile austenite to a slightly harder martensite. These materials under fatigue testing conditions at the macrometric length scale can induce a softening or hardening effect as a function of the underlying deformation feature activated. Thus, given the interaction of single grains in polycrystalline materials, the collective response to macroscopic fatigue testing is not trivial to interpret. Within this context, small scale tests are required to obtain a more in detail understanding of the fatigue properties at the local level of those materials. In this regard, cyclic nanoindentation tests represent a suitable technique to give insight on the local fatigue of metastable stainless steels for a certain crystallographic orientation. In this experimental work, the influence of the testing mode (loading and/or displacement control mode) on the fatigue behavior of austenitic grains as a function of their micromechanical properties as well as their deformation features was investigated in detail. It was found that the experiments done under loading control mode could be compared to conventional low cycle fatigue tests. In contrast when experiments were performed under displacement control mode they may be compared to high cycle fatigue tests. Furthermore, the microstructural observation by transmission electron microscopy allowed to observe the formation of shear bands. This phenomenon preceded the apparition of martensitic laths during the cyclic indentation process.Peer ReviewedPreprin

Reversible phase transformation in polycrystalline TRIP steels induced by cyclic indentation performed at the nanometric length scale

Metastable austenitic stainless steels are an interesting group of materials, which exhibit the Transformation Induced Plasticity effect. In this regard, phase transformation from austenite to martensite enhances the work hardening of the metastable austenitic stainless steels affecting the deformation dynamics and mechanical properties including fatigue properties. Within this context, the reversible load-induced phase transformation from ¿ to ¿-martensite is investigated at the local scale under cyclic indentation. This reversible phase transformation is manifested itself by a combination of hysteresis loops, elbow formation, and reversible pop-ins in the loading curve. The initial cyclic achieved through the nanoindentation technique allows to identify three different deformation regimes for the austenitic grains. Firstly, a softening effect takes place due to the dislocation activation; subsequently the phase transformation induces a hardening effect and finally, the load deformation curve reaches a plateau where no more plastic deformation is observed.Peer ReviewedPostprint (author's final draft