scholarly journals Recent geodynamics: from crustal movements to monitoring the critical objects

2019 ◽  
pp. 78-103
Author(s):  
Yu. O. Kuzmin

The evolution of the views on the subject and methods of recent geodynamics over the past fifty years is outlined. Metrological provision of the results obtained by repeated observations by means of ground-based and satellite geodesy is discussed. The substantial dependence of the main characteristics of recent geodynamical processes on the degree of spatiotemporal detail of the observational systems is demonstrated. A possible solution of the paradoxes of large and small strain rates which were detected in the studies at geodynamical sites in seismically active and aseismic regions is proposed. To explain the anomalous deformational activity on the platform faults, the mechanism of parametric excitation is suggested. According to this mechanism, the time fluctuations in the internal parameters of a fault zone (stiffness, pore pressure, friction coefficient) create local strain anomalies under quasi static external loading. The results of strain monitoring are demonstrated by the example of a shelf oil field. It is substantiated that the geodynamical testing sites are a universal instrument for exploring recent deformational processes which offers a unified framework for establishing the spatiotemporal structure of different-scale geodynamical phenomena addressed in the fundamental and applied studies.

2020 ◽  
Vol 12 (24) ◽  
pp. 10468
Author(s):  
Muhammad Safdar ◽  
Tim Newson ◽  
Colin Schmidt ◽  
Kenichi Sato ◽  
Takuro Fujikawa ◽  
...  

The disposal of 2011 Japan earthquake waste has become an important issue in Japan and it is not realistic or economical to send all of these wastes to landfill sites, due to limited space, high costs, and related environmental issues. In sustainable geotechnical applications, mixing of the separated soils from disaster wastes with additives (e.g., cement and fiber) is required to improve their strength and stiffness characteristics. In this study, monotonic triaxial drained compression tests are performed on medium dense specimens of Toyoura sand-cement-fiber mixtures with different percentages of fiber and cement (e.g., 0–3%) additives. The experimental results indicate that behavior of the mixtures is significantly affected by the concentration of fiber and cement additives. Based on a comprehensive set of test results, modifications to the series of equations were developed that can be used to evaluate the shear modulus and mobilized stress curves at small-strain levels. The experimental results and model comparison show that the elastic threshold strain (γe), reference strain (γr), increases with fiber and cement additives. In addition, the range of curvature parameter, from 0.88 to 1.0, provides a good comparison with the results of small-strain measurements. Overall, the comparison of the results and model shows that the small-strain measurements obtained using local strain transducers fall within the range of model upper and lower bound curves. The results of the unreinforced, fiber, and cemented sand shows a close agreement with the model mean curve, but fiber-reinforced cemented sand shows a good comparison with model upper bound.


2014 ◽  
Vol 7 (4) ◽  
pp. 422-444 ◽  
Author(s):  
Joseph Amankwah-Amoah

Purpose – Although strategic persistence remains a key issue in change management and strategy literature, the understanding of strategic persistence in the face of other businesses’ failure remains limited. The purpose of this paper is to examine factors that determine strategic persistence in the face of other businesses’ failures. Design/methodology/approach – Through a review and synthesis of the multiple streams of research, the paper provides a number of explanations for strategic persistence. The study complements the analysis with illustrative cases of failed companies. These led to development of an integrated framework of explanations for strategic persistence in the wake of other businesses’ failures. Findings – The analysis led to identification of individual, firm-specific and environmental factors rooted in past events (i.e. past successes, prior commitment and decisions by the top-management team), present circumstances (i.e. nature of the failure) and future outlook (i.e. paradox of success, looming threats and opportunities), which foster strategic persistence. The paper uncovered that persistence may also stem from factors such as “paradox of success” and “too much invested to quit”. Research limitations/implications – The paper suggests that organisations can learn from others’ failures without compromising their values by drawing on the expertise released by failed firms. The study also identified various mechanisms through which organisations can learn from the failure of others and factors that constrain them from doing so. Originality/value – The theorisation and conceptualisation of the literature accommodates the multiple and contrasting perspectives of the subject such as the environmental buffers and paradox of success.


2020 ◽  
Vol 10 (20) ◽  
pp. 7194
Author(s):  
Paolo Ruggeri ◽  
Viviene M. E. Fruzzetti ◽  
Giuseppe Scarpelli

International standards discourage the use of grouted anchors with a fixed length exceeding 10 m. However, grouted anchors with a fixed length between 10 and 20 m are frequently used in Italy to transfer high loads to ground with poor geotechnical properties. This paper presents the results of investigation tests on an anchor with a length of 36 m, of which 18 m is fixed, sloping 40° from the horizontal; the anchor is comprised of a reinforced thread-bar which was instrumented with strain gauges and founded in nonhomogeneous ground, a sand deposit followed by marly clay. The test aimed at investigating the progressive mobilization of the shear strength along the foundation. The results indicate a very low shear strength offered by the sand, probably disturbed by the drilling, and an unusually fast mobilization of the shear strength in the marly clay at the deep end of the anchor. The results are particularly useful to identify the reasons for the observed poor performance of the grouted anchor. In particular, the study once again made it clear how important the influence of the execution details on reaching the expected load capacity may be, and likewise the practice of investigation tests on suitably instrumented test anchors.


2021 ◽  
Vol 3 (3) ◽  
pp. 50-75
Author(s):  
E.G. Komissarova

Introduction: the methodology of scientific knowledge plays a dominant role in the system of science as a whole, regardless of the subject and branch of scientific knowledge. The geography of methodological knowledge is gradually expanding, the branch of law is becoming more and more receptive to it. The reason is known, it is in the chronic presence both in the theory of law and in certain branches of law of thematic discourses about methodology, focused on the thematization of its subject qualities. Not without this, lawyers are gradually forming their own methodological “philosophy”, whose semantic differences from the actual philosophical methodology ensure the availability of its tools for lawyers. A natural consequence of the relevance of research interest in methodological values in the future should be to improve the theoretical quality of legal research that is not related to the methodology, but is able to identify its scientific guidelines for the purposes of their own research. Meanwhile, there are few works in jurisprudence that focus on the applied nature of methodological knowledge. Textbooks on the methodology of jurisprudence, intended according to the title information, educational knowledge of its subject features and internal parameters, still go to “distant philosophical distances”, operating with capacious and abstract judgments about methodological phenomena, and therefore are actually addressed not so much to students as to colleagues in the “methodological workshop”. Purpose: to bring the canons of methodological regulations closer to the scientific audience working in other thematic areas that are far from methodological values, but strive to learn them for practical purposes. Methods: descriptive, explanatory, and narrative. Results: based on the results of the study, the author formulated the following theoretical conclusions. The understanding of such a complex phenomenon as the methodology of jurisprudence in its applied meaning is proposed to be carried out according to the “pandect template”. For this purpose, the author “separates” the strictly philosophical and specifically scientific methodology of jurisprudence, offering to distinguish between the general and special parts of the methodological regulations. The general part contains an answer to the subject question what is the methodology and what is the status of methodological knowledge. The special part answers the question of how and what methodological units fill in the methodology parameters and how they work.


Polymers ◽  
2018 ◽  
Vol 10 (7) ◽  
pp. 777 ◽  
Author(s):  
Yanlei Wang ◽  
Yongshuai Wang ◽  
Baoguo Han ◽  
Baolin Wan ◽  
Gaochuang Cai ◽  
...  

In this study, conductive carbon nanofibers (CNFs) were dispersed into epoxy resin and then infused into glass fiber fabric to fabricate CNF/glass fiber-reinforced polymer (GFRP) laminates. The electrical resistance and strain of CNF/GFRP laminates were measured simultaneously during tensile loadings to investigate the in situ strain and damage monitoring capability of CNF/GFRP laminates. The damage evolution and conduction mechanisms of the laminates were also presented. The results indicated that the percolation threshold of CNFs content for CNF/GFRP laminates was 0.86 wt % based on a typical power law. The resistance response during monotonic tensile loading could be classified into three stages corresponding to different damage mechanisms, which demonstrated a good ability of in situ damage monitoring of the CNF/GFRP laminates. In addition, the capacity of in situ strain monitoring of the laminates during small strain stages was also confirmed according to the synchronous and reversible resistance responses to strain under constant cyclic tensile loading. Moreover, the analysis of the resistance responses during incremental amplitude cyclic tensile loading with the maximum strain of 1.5% suggested that in situ strain and damage monitoring of the CNF/GFRP laminates were feasible and stable.


Metals ◽  
2021 ◽  
Vol 11 (2) ◽  
pp. 257
Author(s):  
Anne Tanguy ◽  
Peifang Chen ◽  
Thibaut Chaise ◽  
Daniel Nélias

The case of a frictionless contact between a spherical body and a flat metallic glass is studied using a mesoscopic description of plasticity combined with a semi-analytical description of the elastic deformation in a contact geometry (code ISAAC). Plasticity is described by irreversible strain rearrangements in the maximum deviatoric strain direction, above some random strain threshold. In the absence of adhesion or friction, the plastic deformation is initiated below the surface. To represent the singularities due to adhesion, initial rearrangements are forced at the boundary of the contact. Then, the structural disorder is introduced in two different levels: either in the local strain thresholds for plasticity or in the residual plastic strains. It is shown that the spatial organization of plastic rearrangements is not universal, but it is very dependent on the choice of disorder and external loading conditions. Spatial curved shear bands may appear below the contact but only for a very specific set of parameters, especially those characterizing the random thresholds compared to externally induced strain gradients.


2021 ◽  
Vol 34 (72) ◽  
pp. 1055-1076
Author(s):  
Pierre Guenancia

Descartes e a ideia de homem. Imperfeição e perfeição do homem Resumo: O autor nota, por um lado, que Descartes se refere a uma compreensão muito larga, mas também comum e corrente, do homem e, por outro, que o homem não pode ser identificado nem ao corpo, nem à alma, nem mesmo à união do corpo e da alma. Quando falamos da natureza humana, ela evoca o caráter de uma perfeição limitada, cuja particularidade é sua capacidade de ter o livre-arbítrio. A noção do homem enquanto sujeito de (não) perfeição é baseada sobre uma ideia que se define por uma relação à ideia do infinito sob a forma da aspiração a ser mais perfeito. O exercício do livre-arbítrio se articula concretamente a um esforço de atenção e de vigilância que permite evitar um juízo errôneo. A tese exposta se desenvolve, em seguida, em três tópicos. Primeiramente, a razão se apresenta como um instrumento universal do homem, que, por sua vez, aparece como ser polivalente que o utiliza, sendo capaz de se adaptar às situações as mais diversas. Em segundo lugar, a perfeição especificamente humana significará a capacidade de exercer a dúvida e de recorrer às suposições e probabilidades no plano cognitivo. Isso significa, entre outros, que, para a aquisição da perfeição, é preciso reconhecer a sua própria imperfeição. Enfim, em terceiro lugar, a capacidade de usar propriamente o livre-arbítrio conduz à definição de homem como generoso, em que o homem é compreendido no sentido moral mais que no metafísico. Palavras-chave: Homem; Perfeição; Finitude; Atenção ; Livre arbítrio; Generosidade. Descartes et l’idée de l’homme. Imperfection et perfection de l’homme. Résumé: L'auteur note que, d'une part, Descartes se réfère à une compréhension très large, mais aussi commune et courante de l'homme, et de l'autre que l'homme ne peut pas être identifié ni au corps, ni à l'âme, ni même à l'union du corps et de l'âme. Lorsqu’on parle de la nature humaine, elle porte le caractère d'une perfection limitée, dont la particularité est sa capacité d'avoir le libre arbitre. La notion de l'homme en tant que sujet de (non) perfection est basée sur une idée qui se définit par rapport à l'idée de l'infini sous la forme de l'aspiration à être plus parfait. L’exercice du libre arbitre se joint concrètement à un effort d'attention et de vigilance qui permet d’éviter un jugement erroné. La thèse ci-dessus se développe ensuite en trois points. Premièrement, la raison se présente comme un instrument universel de l'homme qui à son tour apparait comme être polyvalent l'utilisant et étant capable de s'adapter aux situations les plus diverses. Deuxièmement, la perfection spécifiquement humaine signifiera la capacité d’exercer le doute et de recourir aux suppositions et probabilités sur le plan cognitif. Cela signifie entre autres que pour l'acquisition de la perfection, il faut reconnaître sa propre imperfection. Enfin, troisièmement, la capacité d'user proprement le libre arbitre conduit à la définition de l'homme comme généreux, où l'homme est compris au sens moral plus que métaphysique. Mots clé: Homme; La Perfection; Finitude; Attention ; Libre arbitre ; La Générosité. Descartes and the idea of man. Imperfection and perfection of man Abstract: The author notes that, on the one hand, Descartes refers to a very broad, but also common and current understanding of man, and on the other that man cannot be identified nor with the body , neither to the soul, nor even to the union of body and soul. When we speak of human nature, it carries the character of a limited perfection, the particularity of which is the ability to have free will. The notion of man as the subject of (non) perfection is based on an idea which is defined in relation to the idea of ​​infinity in the form of the aspiration to be more perfect. The exercise of free will is joined concretely to an effort of attention and vigilance which makes it possible to avoid erroneous judgment. The thesis above then develops in three points. First, reason presents itself as a universal instrument of man who in turn appears to be versatile, using it and being able to adapt to the most diverse situations. Second, specifically human perfection will mean the ability to exercise doubt and use cognitive assumptions and probabilities. Among other things, this means that in order to acquire perfection, you have to recognize your own imperfection. Finally, thirdly, the ability to use free will properly leads to the definition of man as generous, where man is understood more in the moral sense than in the metaphysical sense. Keywords: Man; Perfection; Finitude; Attention ; Free will ; Generosity. Data de registro: 17/11/2020 Data de aceite: 30/12/2020  


Author(s):  
G. L. Clark

SummaryLittle progress has been made in the development of a relativity theory of elasticity, although it has been realised that no disturbance can be propagated with a velocity greater than that of light. In 1917 Lorentz (1) gave a relativistic formulation of the laws of elasticity in the case of small strain and, applying the theory to the problem of a rotating, incompressible, homogeneous disc, he claimed that the radius as measured by an observer at rest on the disc undergoes a contraction. His result was accepted by Eddington (4) but was attacked by others. A great deal has been written on the subject, but it has never been pointed out that both Lorentz and Eddington were considering material in which the waves of dilatation travel with an infinite velocity. In this paper we define “incompressible” matter as that in which these waves are propagated with the velocity of light and Poisson's ratio tends to the value ½. This gives an upper limit to the modulus of compression k, which in this case is the elastic constant λ, and as a result the expansion determined by the ordinary classical theory has to be taken into account. It is found that the “relativity contraction” is exactly cancelled by the “classical expansion”. Throughout the discussion on the rotating disc the analysis is restricted to the case of small strain.The equations of equilibrium of a continuous static distribution of matter are also investigated in the case of weak fields for which the fourth power of the density may be neglected.


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