The Foziling multi-arch dam, one of the few multi-arch dams in the world, was built on the bedrock with complicated geological conditions. It has undergone several reinforcements since it was put ...into service in the 1950s. In this study, the dam safety is evaluated by analyzing the measured displacements and simulating stresses in the concrete. Firstly, the multiple linear stepwise regression (MLSR) is used to train and test the relationships between the loads and displacement based on the hydrostatic-temperature-time (HTT) model. Subsequently, the contributions of water level, temperature, and time to displacements are determined, and the influence characteristics of water level and temperature on displacements are interpreted. Finally, the dam stress state is evaluated by establishing a dam finite element model and simulating the stress distribution in various operating conditions. The results indicate that (1) the dam is currently in an elastic state after the last reinforcement; (2) temperature contributes the most to the displacement, and the drastic fluctuation of temperature is the disadvantage factor for multi-arch dam safety; (3) the stresses generally can meet the requirements of code; and (4) the ideas and methods of the study can provide references for the safety evaluation of other concrete dams.
Experimental tests on crack propagation in concrete under constant post-peak loading are simulated using the finite element method and the cohesive crack model, in both Mode I and Mixed-mode ...conditions. The time-dependent behaviour of concrete in the process zone is due to the interaction and growth of microcracks, a phenomenon which, for high constant load levels, turns out to be predominant over linear viscoelastic creep in the bulk material. In mechanical systems based on this type of material behaviour (creep and strain-softening taking place simultaneously), the initial value problem is non-parabolic, i.e., the error at one time level is affected by the accumulation of errors introduced at earlier time levels. Despite these difficulties, the scatter in numerical failure lifetime vs. load level turns out to be negligible in Mode I conditions and practically acceptable in Mixed-mode conditions. Therefore the time-dependent behaviour of the process zone can be inferred solely from the results of direct tensile tests.
•The delamination of plasters in the “Sacro Monte di Varallo” historical buildings walls has been simulated in laboratory.•The delamination between repair mortar and masonry stone is characterized by ...a stick-slip behavior.•The AE monitoring describes the delamination fracture modes at plaster-stone interface.
The delamination process of plasters applied for the repair work of historical walls was often caused by humidity phenomena or physical-mechanical cycles stress. In this paper a new experimental methodology has been conducted by testing in the laboratory mixed stone-mortar specimens and analyzing the delamination progression. The experiment simulated the recurring delamination in the stone walls of the Sacro Monte di Varallo, an UNESCO site in Piedmont (Italy). Through the monitoring by means of acoustic emission (AE) sensors during the tests it was possible to qualify the different fracture modes characterizing the delamination process, which takes place during the tests at the interface between plaster mortar and stone block. AE is a non-destructive technique useful to estimate the amount of energy released from fracture propagation in the adherence surface between mortar and stone. The experimental results confirmed the stick-slip behaviour that characterises the friction process inside the delamination surface between repair mortar and masonry stone.
Often masonry walls of historical buildings are subject to rising damp effects due to capillary or rain infiltrations. In the time, their cyclic action produces decay and delamination of historical ...plasters. An experimental laboratory procedure for the pre-qualification of repair mortars is described. Long-term plaster delamination frequently occurs because of the mechanical incompatibility of new repair mortars. The tested mortars are suitable for new dehumidified plasters applied to historical masonry walls. Compression static tests were carried out on composite specimens stSone block-repair mortar, which specific geometry can test the de-bonding process of mortar in adherence with historical masonry structure. A numerical simulation based on the cohesive crack model was used to follow the experimental data, in order to describe the evolutionary phenomenon of de-bonding as a function of a small number of parameters. This method supplies useful indication for selecting the product that is best in keeping with the mechanical characteristics of the historical material, thereby avoiding errors associated with materials that are not mechanically compatible. Currently, the methodology is being used at Sacro Monte di Varallo Special Natural Reserve （UNESCO heritage site） in Piedmont （Italy）.
•The corrosion induced by the water penetration reduces the joint strength properties.•The hydro-mechanical coupling can be taken into account.•The cohesive zone model can be used in the context of ...large scale engineering problems.•The two-stage approach proposed is able to control three different mechanical regimes.
When the long-time behavior of a concrete dam is analyzed, the International Commission of Large Dams recommends to neglect the tensile strength of the dam-foundation joint and to include the uplift pressure due to the water penetrating into the crack. In this context a non-linear problem of contact with friction occurs in the vicinity of the point which separates the damaged part of the joint from the undamaged one. In these conditions the solution depends on the stress path followed during the quasi-static incremental process. Therefore the classical Newton–Raphson fails to converge and has to be replaced by a Large Time Increment method. In this way it was possible to obtain realistic solutions for three different mechanical regimes.
•The simulation of the dam-foundation joint is necessary to analyse the structure.•Since the friction process is dissipative, the solution becomes path-dependent.•Since the friction process is ...path-dependent, a numerical convergence issue is faced.•The convergent excavation prevents the cracks in the lower part of the dam.
In the case of a narrow valley, characterized by a strong rock mass, the excavation can be designed according to the so called convergent way. In this case, the mean value of the compression stresses at the dam-foundation joint increases as the dam moves towards down-stream under the action of the water pressure applied to the up-stream side. During this slip settlement, the stress level in both materials, concrete and rock, remains allowable. It is true that the seismic load is able to increase such a slip displacement, nevertheless, since the structure is designed for horizontal hydrostatic loads, the stress level remains allowable even in such a seismic condition. The above mentioned issue was discussed during the 14th Benchmark Workshop on the Numerical Analysis of Dams organized by the International Commission on Large Dams (Stockholm, 6–9 September 2017). The theme B of the above mentioned Workshop was the static and seismic analysis of the Janneh dam. It is an arc-gravity dam, 157 meters high, now under construction in Lebanon, a high-seismicity region. The ten participants compared their results, obtained independently from each other and through different numerical models. In this paper the contribution of the authors is presented and the mechanical hypotheses at the base of the three-dimensional evolution of the crack path, at the dam-foundation joint, are discussed.
The nonlinear behavior of concrete-like materials in tension is characterised by strain-softening. Phenomena involving the localisation of strain caused by strain softening can be analysed accurately ...through the so-called “cohesive crack model” which uses the length of the fictitious crack as a control variable. In this approach, the length of the process zone is not fixed and the ratio between this length and the length of the specimen decreases with increasing size-scale. This phenomenon is evident even for small changes in size. It can explain why, in four point shear test, a critical size is observed, below which a secondary crack starts to propagate. This is a size-related phenomenon of bifurcation of equilibrium path, which is predicted by the cohesive crack model and confirmed experimentally. The theoretical results obtained by means of the cohesive crack model involving two cracks are in good agreement with experimental results.
As diretivas antecipadas de vontade para o fim da vida são documentos que expressam os desejos da pessoa relacionados aos procedimentos que podem ser aplicados a ela em uma situação de assistência ...médica no fim da vida. Nesse sentido, as diretivas são úteis para informar as equipes de assistência médica a respeito dos tipos específicos de tratamento que o paciente permite, ou não permite, quando não estiver apto a manifestar suas vontades em uma hipotética situação futura de incapacidade. Este tipo de documento foi elaborado nos Estados Unidos na década de 1970, e foi introduzido no ordenamento ético brasileiro pela Resolução 1995/2012 do Conselho Federal de Medicina. O objetivo desta dissertação é estudar essa norma ética sob o enfoque do direito penal, uma vez que as diretivas antecipadas de vontade para o fim da vida possuem uma íntima relação com a ortotanásia e a eutanásia, que são passíveis de sanção penal no Brasil. Assim, é fundamental analisar as diretivas antecipadas utilizando as ferramentas da doutrina penal, e princípios como os da dignidade humana e razoabilidade. O objetivo é pesquisar as qualidades, imperfeições e limites das diretivas antecipadas sob o ordenamento jurídico nacional, e também compreender as bases legais das diretivas antecipadas, que são os institutos da autonomia e do consentimento. Concluímos que, ainda que as diretivas antecipadas de vontade sejam uma norma ética bem-vinda, demandam algumas melhorias e refinamentos, que poderiam ser representados pelos planejamentos antecipados de tratamentos, um tipo de documento direcionado aos valores de vida das pessoas. Além disso, uma mudança de paradigma relacionada à eutanásia, particularmente a eutanásia passiva e a ortotanásia, no sentido de descriminalizá-las, seria importante para que as diretivas antecipadas tenham eficácia no Brasil.
Advance directives for dying patients are documents which express personal desires related to procedures that may be applied to people in a situation of medical assistance in the end of life. In this sense, they are useful to make health assistance teams know about what kind of specific treatment the patients permit, or do not permit, when they are not able to communicate their wishes in a hypothetical and future situation of disability. This kind of document was created in the United States in the seventies, and entered Brazilian ethical law by Resolution 1995/2012 of the Federal Council of Medicine. The aim of this dissertation is to study this ethical rule by means of the criminal law, because advance directives have a close relation to euthanasia and ortothanasia, which are prone to criminal sanction in Brazil. Therefore, it is paramount to analyze the advance directives using the doctrinal tools of criminal law and principles like human dignity and reasonability. The goal is surveying the qualities, inadequacies and limits of advance directives under Brazilian law, and also to understand the legal basis of the advance directives, which are the institutes of autonomy and consent. We concluded that, although advance directives for dying patients are a welcome ethical law, it demands some improvement and refinement, which could be represented by the advance care planning, a kind of document that is focused on the life values of people. Furthermore, a change of paradigm related to euthanasia, particularly passive euthanasia and ortothanasia, in the direction of making them apart of criminalization, would be vital to promote the adequate efficacy of the advance directives in Brazil.
Technology and Influence on Innovation Loureiro, Ruben Joaquim Pinto; Simões, Jorge Manuel Marques; Silva, Sílvio Manuel Valente da ...
Journal of business and economics (Bradenton, Fla.),
04/2019, Letnik:
10, Številka:
4
Journal Article
Innovation can be the key element of a company, yet it is dependent on business resources. The relationship between innovation and performance is addressed by several authors who advocate this theme ...as a driver to solve problems at the business level and subsequently improve performance. Innovation is essentially under great uncertainty, but little information exists about innovation in developing countries. The present research aims to add knowledge about innovation in developing countries, analyzing whether innovation improves business performance (influenced by technology). Thus, the research question is: What is the relationship between innovation and performance in companies? These hypotheses are related to a specific objective: to identify the factors that improve the company’s performance. Using secondary data obtained by the World Bank, and seeking to make known developments in innovation and the relationship with technology and performance in developing countries, the correlation of several variables was worked out in a first approach to the theme through an analysis factorial. It is concluded that there is no positive relationship between performance and innovation in developing countries.
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