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In simulation of fractured rock mass such as mechanical calculation, hydraulic calculation or coupled hydro-mechanical calculation, the representative element volume of fractured rock mass in the simulating code is very important and give the success of simulation works. The difficulties of how to make a representative element volume are come from the numerous fractures distributed in different orientation, length, location of the actual fracture network. Based on study of fracture characteristics of some fractured sites in the world, the paper presented some main items concerning to the fracture properties. A methodology of re-generating a representative element volume of fractured rock mass by DEAL.II code was presented in this paper. Finally, some applications were introduced to highlight the performance as well as efficiency of this methodology.

O presente artigo visa construir, a partir das canções escolhidas por Eduardo Coutinho para o documentário As Canções (Brasil, 2001), um paralelo entre a representação de brasileiros e parte da literatura que aborda o tema, mais especificamente em obras de Marilena Chauí, Darcy Ribeiro e Sergio Buarque de Holanda. O texto é iniciado apresentando-se o contexto da utilização do gênero canção como elemento representativo da sociedade, da história do documentário e posteriormente, apresenta-se um retrato da sociedade brasileira em relação à análise de personagens da peça audiovisual propriamente dita. Como resultados da análise, é possível observar que o diretor de As Canções, se utilizou do gênero canção e da escolha das obras como parte do processo de produção do filme e como forma de representação de parte da sociedade brasileira.

This paper presents a novel and straightforward procedure for the derivation of homogenized failure surfaces for non-periodic masonry. The most innovative feature of this procedure is the automatic generation of a convenient finite element mesh directly from the sketch of the considered masonry panel, based on the so-called “pixel strategy” that converts each pixel into an element. An upper bound limit analysis problem coupled with homogenization is then solved by aptly formulating it as a linear programming problem. Another main feature is the implementation of a reduced formulation of such problem (called “master-slave approach”) so that the number of unknown variables is reduced and, consequently, the computational times needed for the extraction of the homogenized failure surfaces are shortened as well. A simple procedure is also implemented for a quick identification of the statistical Representative Element of Volume (or REV) for a non-periodic masonry panel. The REV is the smallest portion of a composite material that includes all the physical and geometrical characteristics needed for its complete description. The reliability of the procedure is tested by investigating six case studies displaying different degrees of non-periodicity, extracting and critically commenting the results obtained in terms of homogenized failure surfaces and failure modes.

Specialty about balcony as a building element is explained through its attribute of connecting different spheres that are public and private, the individual and collective, the indoor and outdoor (BK at the Biennale: anatomy of a balcony, 2014). Regarding it as the border between public and private, the individual and collective, the indoor and outdoor; this study aims to display the role of balcony railings of modern apartment block typology that developed rapidly through Flat Ownership Law in 1965, as a representative element of collective memory. Thus, the year 1965 marks a turning point in terms of housing production that in turn defines the new face of Ankara streets. The standardization of the apartment block due to the limitations of urban parcels forced architects or builders to search for means of breaking the monotony of this new face. One of the subsidiary elements were iron balcony railings that could be defined as “industrialized ornament”. They act as a retouching in an industrial way in order to aesthetize what is very ordinary. This tactic of building supports Heynen’s idea of dwelling, as in the first instance being associated with tradition, security, and harmony. The aesthetized balcony railings are a response to the dilemma created by the ordinary apartment block typolog and the idea of dwelling. The representative role of balcony railings will be exhibited through an archival study on balcony railings of Ankara, in which nine districts (Bahçelievler, Emek, Anıttepe, Maltepe, Kızılay, Küçükeast, Kavaklıdere, Gaziosmanpaşa, Çankaya) were selected as the case study. Around 1900 apartment buildings built between 1950 and 1975 that carried the characteristics of “modernized ornament” were photographed and the photographs were categorized according to the following criteria: style, form, material, details, use of color, etc. In parallel with Durkheim’s belief that every society exhibits and requires a sense of continuity with the past, this study aims to reveal that the archival of these railings as a representative element would remind Ankara dwellers of their shared memory.

A synthetic rock mass (SRM) model coupling discrete fracture networks (DFNs) and a discrete element grain-based model (DEM) is used to characterize the mechanical properties of moderately jointed rockmasses under confined and unconfined conditions. The scale dependency of the rockmass properties is investigated using the concept of representative element volume (REV). The numerical results are compared with the estimated values from empirical methods. It is determined that the empirical Hoek-Brown criterion correctly estimates the unconfined strength of the rockmass with non-persistent joints, while it overestimates the strength under confined conditions. An S-shaped strength envelope is obtained from the numerical results.

A regularized lattice Bhatnagar–Gross–Krook model for flow and heat transfer in porous media at the representative element volume scale is presented. In the model, the regularization process is extended to the existing Darcy–Forchheimer-based lattice Bhatnagar–Gross–Krook scheme. Numerical results show good agreement between the present model and the previous ones. Also, the present model shows better numerical stability than its lattice Bhatnagar–Gross–Krook counterpart.

As a popularly adopted design of thin-walled energy absorber, a circular tube under free inversion has been studied theoretically since 1960s However, in all the existing models, the profile of inversion is assumed to be a semi-circle, i.e., the curvature in the region of inversion is a constant. In this study, from equilibrium of a representative element, the curvature is found to be varying, due to bending moment distribution. The conclusion of varying curvature is verified by the corresponding finite element simulations. Then the deformation mechanism of a tube under free inversion is theoretically investigated by establishing a curvature varying model. Considering the interaction of bending and tension, the steady inversion load and knuckle radius predicted by current model agree well with those obtained from FE simulations as well as the experimental data published in literature.

Digital rock analysis (DRA) has exhibited strong ability and significant potential to help people to image geological microstructures and understand transport mechanisms in rocks underground, especially for unconventional reservoirs like tight sandstone and shale. More and more new technologies have been developed for higher resolutions, which always come with higher expense. However, the balance between cost (money and time) and benefit has never been figured out quantitatively for these studies. As the cost and benefit are directly related to image resolution and size, this work is focusing on whether there is a critical resolution and sample size when using DRA for accurate enough predictions of rock properties. By numerically changing the digital resolutions of the reconstructed structures from high-resolution micro-computed tomography (CT) scanned tight rock samples, it is found that the permeability predictions get stable when the resolution is higher than a cut-off resolution (COR). Different from physical rocks, the representative element volume (REV) of a digital rock is influenced by the digital resolution. The results of pore-scale modeling indicate that once sample size is larger than the critical sample size and the scan resolution higher than the critical resolution for a given rock, the predicted rock properties by DRA are accurate and representative.

El objetivo de este estudio era conocer la imagen que tienen los habitantes de A Coruña sobre su ciudad. Con este fin, se presentó el cuestionario utilizado por Boira (1992), con algunas modificaciones, a un grupo de 130 estudiantes de la Facultad de Ciencias de la Educación de la ciudad de A Coruña (España). Se confirma el papel central de la Torre de Hércules como elemento simbólico y representativo, la asociación de ésta y del mar y las playas con la idea que la mayoría tiene de la ciudad, y la percepción de las plazas de María Pita y de Pontevedra como corazón de la ciudad y como nodo más importante, respectivamente. La ciudad ha sido descrita por muchos participantes como “una ciudad pequeña con todos los servicios cerca”.

In the late fifteenth century the helical staircase appeared in Spain as a representative element of late Gothic architecture. To gain a better understanding of this staircase and to carry out a proper preservation plan, it is essential to deepen our understanding of its construction and structure. This involves getting to know its geometrical configuration in depth, since its structural stability was ensured by rules of proportions. For this reason, this paper focuses on two broad types of staircases, classified according to the geometrical design strategy that solves the central aperture: the helical staircase by “radial solution” and by “tangent solution”. The paper analyzes both solutions on the basis of objective criteria. In addition, it considers whether the limited use of some of these solutions was motivated by their particular geometry or was caused by other reasons is addressed. As result of this study it is demonstrated that although the two approaches solve the helical staircase in a similar way, the oblivion of the tangent approach was more objectively motivated.

Any element used in a pedagogical work is important as long as it points towards innovation and improvement for educational practices, as well as the motivation of children and young people for their academic formation. The proposal intends to show the scope of the pedagogical experience with the secondary and middle school students of the “Nuestra Senora del Pilar” Educational Institution of the municipality of Guatape - Colombia, which has tried to use a representative element of its culture: the zocalo, as a didactic tool and its contribution in the teaching of the social sciences applied in each of its disciplines, at the same time, where learning is motivated and generates, in the students, an interest in the investigative thought.

The effect of applied load on density–pressure dependence as well as density distribution under axial pressing of powders in closed dies is analyzed. The continuity hypothesis is used for the analysis. The notion of a representative element is introduced. It is established that the size of this element is related to the effective diameter of powder particles. The sensitivity of density–pressure dependence and density distribution to pressing conditions is explained. Some features of axial pressing with a rotating punch are pointed out. The personal contribution of I. D. Radomyselskii to the formulation and solution of basic problems of powder pressing theory is emphasized.

A detailed study is described of the post-yield behaviour of four medium-plasticity heavily overconsolidated UK stiff clays. Sub-layers of the stiff-to-hard Gault, Kimmeridge and Oxford clays were identified, sampled and tested; these, along with facies investigated in an earlier London Clay study, had broadly similar depositional histories. The intention in considering a spread of similar sediments from the Jurassic to the Eocene was to allow any strong effects of geological age, or burial depth, to be identified. A strongly fissured meso-structure was present in three of the four clays, which had a controlling influence on their effective shear strengths, considering that the representative element volume is of paramount importance in measuring the strengths of such soils. All four soils were brittle in shear and, when sheared to sufficient displacements, developed low residual shear strengths. The stiff clays were investigated further through comparisons between natural and reconstituted behaviour, using the latter to normalise the effective stress data for volume and also considering the clays' oedometer swell sensitivities. Normal compression tests, when normalised for void index, implied different degrees of ‘structure' than undrained shear tests, showing that a more elaborate micro- and meso-fabric framework is needed to capture the behaviour of highly overconsolidated and aged geomaterials. This paper focuses on describing the study sites' geotechnical profiles and the stiff clays' yielding behaviours under one-dimensional compression and in triaxial compressive shear.

For dual-pore-fracture rock mass, by considering the effect of facture weakening, a method for determining the cohesion c N and internal friction angle O N of arbitrary plane in a representative element was suggested. It was proven to be reasonable for the coordination of the anisotropy variation curves of rock mass strength obtained by this and Attewell's methods. Introducing the method for the solving of c N and O N into the elastic-plastic FEM code developed by the authors, aimed at a rectangular underground cave, three cases with different fracture states were computed. The results show that with the increasing of fracture set number, the cohesion and internal friction angle of rock mass and the plasticity zone decreased and sharply, nonlinearly grew respectively, and the magnitude and distribution of stress and displacement in the surrounding rock mass changed obviously.

Axisymmetric extrusion and drawing through a die of arbitrary shape is analyzed by the Orowan method. The stress state in a representative element is determined by solving a boundary value problem of plasticity theory.

Studies of strains within granular assemblies using digital image correlation have shown that as the resolution of observation becomes finer so the detail of the local variations of strains becomes more complex. The scale of this observed complexity is typically of the order of a few (5–10?) particles. The notion of a localised shear band of uniform shear or volumetric strain is not easily supported. In addition, studies reveal somewhat regular patterns of heterogeneity within samples which have been subjected to uniform external boundary deformations. A heterogeneous state is the natural state for granular materials. These observations have implications for the scales that should be adopted for testing of granular materials either in single-element or in physical model tests. Testing of a single element of a size that just accommodates a single region of ‘localisation’ will inevitably impose constraints on the particles in this region. On the other hand, one can envisage a representative element that is uniformly heterogeneous. Such an element would need to have dimensions that are large in comparison with the dimensions of the building blocks of the patterns of heterogeneity. These would define a length scale that is two orders of magnitude greater than typical particle sizes.

An elastic-plastic model was developed to describe the deformation and permeability of fractured rocks under confining pressure. Elastic and elastic-plastic contact models were used in the model to analyze the deformations of a representative element containing a single fracture under various confining pressures. The present work utilized elements from contact mechanics and viscous flows to derive an expression for permeability of fractured rocks under a range of confining pressures. The elastic-plastic model predictions for coal permeability under loading and unloading confining pressure were compared with the experimental data. The new model exhibited trends similar to the data for the range of confining pressures used in the experiments. The model can be used to predict the permeability of other fractured media with different material properties.

This paper aims to determine the strength properties of jointed rock masses by means of the homogenization method. To reflect the microstructure of jointed rock masses, a representative element volume (REV) is selected. Assuming being rigid and perfectly plastic and utilizing the Mohr-Coulomb yield criterion for rock and joints, an upper bound limit analysis method is proposed based on the homogenization theory. By using the finite element method and Goodman joint element, a nonlinear mathematical programming with equality constraints is formulated, which can be solved by a direct iterative algorithm. Numerical results show the strength of jointed rock masses behaves anisotropy with different joint directions. This method presents an effective tool for the strength analysis of jointed rock masses.

Laboratory metal dusting test of several Ni binary alloys containing the representative element was conducted in a simulated syngas atmosphere at 650°C for 100h. The Ni alloys containing element belonging to Group 14 and 15 in the periodic series exhibited excellent metal dusting resistance, while those containing Group 13 did not. This behavior was able to be reasonably interpreted from the Blyholder mechanism and the concept of Pauling’s electronegativity.

Discontinuities such as fractures or cracks are common in geo-materials. Connectivity is a comprehensive parameter that includes the influence of length, orientation and density of the discontinuities. The main objectives of this paper are to define connectivity based on the statistical geometrical parameters of a network of random discontinuities and to quantify the hydraulic properties of the network using connectivity. An analytical method is first proposed to evaluate connectivity through the density of degree of freedom (DDOF). The analytically estimated DDOF is verified using numerical analysis. DDOF increases with the increases in the mean length, relative orientation and density of the random discontinuity network. Connectivity becomes better and the permeability becomes larger with increasing DDOF. The representative element volume (REV) of a random discontinuity network can be estimated based on connectivity. When a discontinuity network is poorly connected, a REV does not exist when the size of the discontinuity network is smaller than 10 times of the mean length of the discontinuities. When a discontinuity network is normally connected, a REV exists when the REV size is smaller than 10 times of the mean length of the discontinuities. When the discontinuity network is highly connected, the REV size is only 2–4 times of the mean length of the discontinuities. The results indicate that DDOF is a good indicator to quantify the connectivity of a random discontinuity network and the relationship between connectivity and permeability.

Culture is the most representative element of any country, nation or city, and museums are one of the best mediums for its transmission. The Capital Museum exemplifies Beijing’s urban culture; its ...

The destruction of forests in Panama, the effects of climate change, collectors and illegal trafficking has led to Orchid Peristeria Elata having the status of endangered species. Known in Panama under the name Flower of the Holy Spirit, this orchid has been declared by law as representative element of Panamanian folklore. Despite the efforts made to conserve this orchid in its natural habitat, the results are still insufficient. In this paper we propose using an open source platform for low-cost computing to monitor and control environmental conditions in an unheated greenhouse for the care of the orchid Peristeria Elata. This platform is based on the Web and Arduino technology. Through this platform the monitoring will be done remotely; using sensors, a set of environmental variables will be monitored inside the greenhouse and irrigation mechanisms will be controlled. Using these technologies can play similar conditions this orchid in their natural habitat.

The connection of Bal'shin consolidation theory with contemporary compaction mechanics is considered. The main principles of Bal'shin and proposals for powder compaction theory formulated by him are analyzed. A connection is established between the identity principle and the hypothesis of the existence of a representative element, and one possible way of determining its dimensions is demonstrated. The main attention is devoted to the hypothesis of continuity and the results of compaction mechanics, which are obtained based on it. A connection is noted between consolidation theory and the concept of the mean-square viscous stresses of Skorokhod. Problems of Bal'shin are indicated that may easily be resolved by means of the concept of mean-square viscous stress. The relative solution of the problem of evaluating density distribution is noted. Problems are discussed for powder breaking directly during compaction in a rigid die. The contribution of scientists from Armenia, Belarus, Russia and Ukraine in setting up contemporary compaction mechanics is evaluated.

Cold joint in concrete due to delayed concrete placing may cause a reduced shear resistance and increased water permeation. This study presents an analytical model based on the concept of REV (Representative Element Volume) to assess the effect of water permeability in cold joint concrete. Here, OPC (Ordinary Portland Cement) concrete samples with cold joint are prepared and WPT (Water Permeability Test) is performed on the samples cured for 91 days. In order to account for the effect of GGBFS (Granulated Ground Blast Furnace Slag) on water permeability, concrete samples with the same W/B (Water to Binder) ratio and 40% replacement ratio of GGBFS are tested as well. Utilizing the previous models handling porosity and saturation, the analysis technique for equivalent water permeability with effective cold joint width is proposed. Water permeability in cold joint increases to 140.7% in control case but it decreases to 120.7% through GGBFS replacement. Simulation results agree reasonably well with experimental data gathered for sound and cold joint concrete.

The Itapema formation consists fairly of a limestone reservoir section with coquinas (shell fragments) deposited under high salinity lacustrine conditions. The environment in which this deposits accumulated along with the diagenetic processes subsequently undertaken created reservoir rocks with high heterogeneity in several scales of investigation. The representative elementary length plays a major role to characterize such reservoirs. The present work describes a quantitative approach to determine the size of a representative elementary area (REA) using both numerical and statistical methods defined for a Coquinas analogue. Two effective properties are determined for the REA: Porosity and Permeability. The porosity is defined here as the visible porosity from a micro tomography slice and the permeability estimated from a virtual Darcy's experiment using a finite element implementation of Brinkman's equation. Brinkman's equation is deemed necessary to properly model the flow within the vugs and porous matrix. The REA is subject to periodic boundary conditions with a pressure gradient on each boundary face. The variance is estimated and used as a statistical instrument to guide the REA size and later compared to the results obtained from the porosity and permeability estimations. The laboratory routine core analysis (RCA) provides a bulk measurement for porosity and permeability of the whole Coquinas sample. The RCA is used to constraint the obtained results for the simulations and statistical estimation and delineate the asymptotic behavior.

A model and design model for representative-element analysis of the decay of the Saint-Venant edge effects in laminated materials are proposed. The decay of the edge effect in a matrix with laminated covering (a composite material of irregular structure) is considered for the case of symmetric deformation. The source of the edge effect is simulated by a piecewise-constant surface periodic load normal to the layers. This load is local for the working domain and is varied within a boundary section that is commensurable with the characteristic size of the heterogeneity of the material structure. The equations of the linear theory of elasticity, a model of a piecewise-homogeneous medium, and quantitative criteria for identification of edge effects are used. A discrete model of the problem and its solution are constructed within the concept of basic schemes. Data on the zone of the edge effect and the character of its decay for a representative element of the material are analyzed.

De manera paralela al desarrollo del magisterio de capilla ejercido por Melchor López en la catedral de Santiago de Compostela (1783-1822), se produjo la renovación de su orquesta hasta alcanzar de un modo estable los patrones del tipo básico de orquesta sinfónica clásica surgido con fuerza en Europa central años antes. Este hecho infl uyó en la música del maestro, formado en Madrid y admirador de la música de F. J. Haydn, donde el acompañamiento orquestal preciosista a las voces solistas y al coro, se convirtió en protagonista de la misma, posibilitando además la renovación del repertorio instrumental que se interpretaba en las funciones litúrgicas (Misas, Vísperas) y en otros momentos paralelos a los litúrigicos como eran las siestas que se celebraban durante el octavario del Corpus. Dentro de esta renovación, tuvo especial importancia la recepción del estilo de Haydn, cuyas sinfonías llegaron a la catedral en la década de 1790 y son quizá el elemento más representativo de la renovación de dicho repertorio. At the same time as Melchor López was carrying out his teaching duties within the music chapel of the cathedral of Santiago (1783-1822), the renovation of his orchestra was undertaken to the point of accomplishing a stable symphony orchestra of the classical sort which had long been fi rmly established in Central Europe. This greatly infl uenced the maestro’s music, having studied in Madrid and admirer of F.J. Haydn’s music, where the precise orchestral accompaniment for solo voices and for choirs became the central part of his works and made possible the renovation of the instrumental repertoire which was being used in the liturgy (Masses, Vespers) and on other occasions for paraliturgy functions such as the siestas celebrated during the octave of Corpus. Within this renovation, the reception of Haydn’s infl uence was especially important: his symphonies arrived at the cathedral in the 1790s and are perhaps the most representative element of this renovation which the aforementioned repertoire underwent

A new constitutional balance. The benefits of guaranteed assemblies: the core proposition of parliamentarianism. The significance of parliamentary law as “that which makes and constitutes a kingdom”: the practical and philosophical justification for a representative element in government.