Search

Impact loadings such as vehicle collisions or falling rocks on a structure could lead it to collapse and, eventually, to fatal victims. Among possible alternatives to analyse this issue, Lumped Damage Mechanics is an interesting option due to its formulation and easiness for practical application. Therefore, this paper presents a simplified Lumped Damage model to evaluate reinforced concrete structures under impact loads with shear failure mode. In the proposed approach, the damage variable is considered as an output parameter. Such damage variable takes values between zero and one, which quantifies the concrete cracking due to impact loading. The proposed formulation was applied in experiments of reinforced concrete beams under impact loads that presents shear collapse. The obtained results showed good accuracy between the proposed model and the actual structural behaviour. Moreover, a possible flowchart for practical applications is also presented. Since the model parameters are easily associated to inelastic phenomena, the proposed formulation might become accessible to engineers in practice.

Reinforced concrete structures may need repair in order to ensure the designed durability. The assessment of the structural condition usually is made in loco, but sometimes numerical analyses are required as a low cost and effective preliminary diagnosis. Lumped damage mechanics (LDM) may be used as an alternative diagnosis procedure. In LDM approaches for reinforced concrete structures, the concrete cracking in modelled by a damage variable and the reinforcement yielding is represented by plastic deformations. Therefore, this paper presents LDM as a diagnosis tool to analyse actual structures. Then, the procedure is applied in two case studies. The first one is a former bridge arch tested in laboratory. Such bridge was deactivated after almost three decades in service and some damage were observable. The second case study deals with a reinforced concrete balcony that collapsed after fifteen years of service. In the moment of collapse, only the dead load was acting in the balcony. The results show that LDM numerical response of those structures are quite close to laboratory observations, for the former bridge arch, and to in loco measurements, for the balcony. In this sense, according to the analysed structures, LDM may be used as a diagnosis tool

Analysis of RC structures subjected to seismic loads vary greatly around the world, from simplified static models to more advanced methods, which take account of real dynamic loads and the nonlinear response of structures. As a recent theory, lumped damage mechanics apply the concepts of damage mechanics and the classic fracture in plastic hinges for nonlinear analysis of RC structures. Therefore, this research analysed the behaviour of RC dual system structures designed according to Brazilian Standards Codes, that did not consider the recommendations of NBR 15421, under seven real seismic loads, with magnitude units in Richter scale (ML). It was concluded that all structures regardless of structural system and number of storeys might suffer severe values of structural damage when subjected to earthquake magnitudes equal or greater than 5.0 ML. Besides that, even for earthquake magnitudes above 3.0 ML, in most of structures, the interstorey drift ratio was not in requirements with international standard codes, causing cracking in nonstructural elements and demanding higher repair costs.

The analysis of reinforced concrete structures can be performed by means of experiments or numerical studies. The first way is usually quite expensive, so the second one sometimes is a good option to understand the physical behaviour of actual structures. Lumped damage mechanics appears as one of the latest nonlinear theories and presents itself as an interesting alternative to analyse the mechanical behaviour of reinforced concrete structures. The lumped damage mechanic applies concepts of the classic fracture and damage mechanics in plastic hinges for nonlinear analysis of reinforced concrete structures. Therefore, this paper deals with a novel physical definition of the correction factor γ for cracking evolution that ensures the presented lumped damage model depicts accuracy when it is compared to experimental observations of reinforced concrete beams and arches. Based on such experiments, the numerical analysis showed that γ value has upper and lower thresholds, depending on the physical and geometric properties of the reinforced concrete element. Notwithstanding, for γ values inside of the proposed interval, there is a best value of γ.

This work proposes a new simplified parameter for the calculation of second order global effects, based on the Galerkin’s Method by Weighted Residuals. The proposed criterion was analysed based on 21 planar frames associated with shear wall, reaching results that present satisfactory accuracy compared to the second order global analysis, even for cases where the γz coefficient is greater than 1.30. Resumo Neste trabalho propõe-se um novo parâmetro simplificado para o cálculo dos efeitos globais de segunda ordem, a partir do Método de Galerkin via Resíduos Ponderados. O critério proposto foi analisado com base em 21 pórticos planos associados a pilar-parede, alcançando resultados que apresentam acurácia satisfatória com relação à análise global de segunda ordem, mesmo para os casos em que o coeficiente γz é superior a 1,30.

Structural design procedures are based on simplified hypotheses that attempt to approximate the actual behaviour. Depending on the adopted hypothesis, the design procedure may not satisfactorily describe the structural actual behaviour. Such condition occurs in the design of reinforced concrete pipes, where there are uncertainties related especially on the internal forces and the installation type of the pipe. Moreover, the main design hypothesis is that the cross section is plane and perpendicular to the deformed axis. Based on materials resistance principles it is known that this hypothesis is unsatisfactory to pipes with aspect ratio lower than ten. Note that the commercial reinforced concrete pipes usually present aspect ratio well below ten. In the light of the foregoing, the main objective of this paper is to analyse the accuracy of the design procedure for reinforced concrete pipes. Therefore, statistical processes were used to compare design values with experimental results. The comparisons in this paper showed that the design procedure results in oversized pipes.

O gerenciamento hídrico compreende não só a captação de dados, mas também o tratamento, armazenamento e posterior apresentação ao usuário. Deste modo, o presente trabalho buscou desenvolver uma aplicação web usando a biblioteca Google Charts para que os dados sejam apresentados de forma gráfica. O trabalho desenvolvido no Laboratório de Hidráulica do Instituto de Ciências Agrárias da Universidade Federal de Minas Gerais, valeu-se da linguagem de programação JavaScript e da biblioteca jQuery para recuperar dados de um reservatório, armazenados em um servidor web e plotá-los em uma página HTML. Deste modo, criou-se uma aplicação que apresenta ao usuário o estado de um reservatório em tempo real, pois, o gráfico de nível do mesmo é atualizado a cada minuto. Concluiu-se então que o uso da biblioteca Google Charts no gerenciamento hídrico é viável, apresentando a gestores de recursos hídricos uma nova ferramenta de apoio a tomada de decisões. Water management comprises not only the capture of data, but also the treatment, storage and subsequent presentationto the user. Thus, the present work sought to develop a Web application using the Google Charts library so that the data will be presented graphically. The work, developed at the Hydraulics Laboratory of the Agricultural Science Institute of the Federal University of Minas Gerais, used the JavaScript programming language and the jQuery library to retrieve data from a reservoir, stored on a Web server, and plot them in an HTML page. In this way, an application is created that presents the user with the state of a reservoir in real time, Therefore, the same level chart is updated every minute. It was then concluded that the use of the Google Charts Library in water management is feasible, introducing water resource managers a new tool to support decision-making.

Objective Hand sensory tests do not consider distinct physiological receptors, nor detect normal range variations concerning developmental or pathological changes. We developed an instrument with a set of tests with timing and scoring for assessing haptic perception, which is the interaction between sensory and motor systems, in surfaces exploration, by moving hands. Method Firstly, group meetings were set for test/manual conception and materials testing. The test/manual were submitted to 30 reviewers in 3 stages (10 reviewers on each stage). Results The Hand Haptic Perception Instrument (HHPI) evaluates hand sensorimotor performance on six domains: depression, elevation, texture, compressibility, weight (barognosis) and form perception. Each domain requires specific materials. Score ranges from 0 to 57, being 0 the worst rating. Conclusion This methodological process allowed the development of six domains and instructions to assess haptic perception. This version of HHPI is a pilot model. Further studies will determine reliability and normality ranges.

This paper presents a simple lumped damage model to analyse reinforced concrete beams under impact loads. The proposed model is based on the thermodynamics of irreversible processes. In this framework, key concepts of fracture and damage mechanics are applied on plastic hinges. Since the inelastic phenomena are modelled by two internal variables, named damage and plastic rotation, the plastic hinges are now called inelastic hinges. Therefore, the proposed finite element is an assemblage of an elastic beam with two inelastic hinges at its edges. Experimental results are used to propose the evolution laws of the internal variables. The proposed model is applied to other experiments and the obtained results show its accuracy. Finally, if an extensive experimental campaign could be carried out, a practical engineering criterion can be elaborated in terms of the damage variable (concrete cracking), which may be useful as a decision-making criteria for retrofit worthiness.

When managing software development projects, it is common to have some problems during the iterations of the project. This work presents an analysis and review of agile methodologies and some of the most well-known project management techniques, all these methodologies and techniques contextualized in the computational scope. Based on this information was possible to propose a new model more comprehensive that allows the mitigation of some recurring problems in the progress of software projects and give to final users good results. It was detailed a case study of an innovative project entitled “Calculadora CUG”, where the combination of referenced techniques and concepts were introduced in the development process allowing more flow to some of the features of the project pointed out by the client (first final user) and to create, in a way, more efficient releases in involvement with the user.

This paper presents a formulation for the analysis of the inelastic behavior of pipes, tunnels and rings. This new framework is based on lumped damage mechanics and emphasizes on the mathematical description of concrete cracking; the approach can be extended to other brittle materials as well. Lumped damage mechanics combines the concept of plastic hinge with the ideas and procedures of fracture and continuum damage mechanics. The resulting models allow for the characterization of the damage state of the structure, it is even possible to quantify the crack opening displacements in a simplified way. Experimental and fracture mechanics results were used to validate the proposed method. The structural analyses can be carried out using very few elements (less than a dozen in most cases) while the conventional approaches require tens of thousands of them. Thus, even if the models can be implemented in conventional finite element programs, the computations can also be carried out with symbolic manipulators, general numerical analysis programs (Maple, Matlab, Mathematica, Mathcad, and so on) or even spreadsheet applications. This simplified approach can be used for design purposes, validation of finite element analysis or structural reliability assessment where thousands of analyses of a same structure are needed.

In the present article, we provide shortly, data on risk factors for acquiring Toxocara spp. infection and investigate possible associations between this infection with atopy and asthma in school children of a small town and its semi-rural areas of Northeast Brazil. The data set are composed by demographic, social and home environment variables. The detection of anti-Toxocara spp. IgG and specific IgE to aeroallergens was determined by ELISA and ImmunocAP/Phadiatrope systems, respectively. The data presented in this article are related to the article entitled “Risk factors for Toxocara spp. seroprevalence and its association with atopy and asthma phenotypes in school-age children in a small town and semi-rural areas of Northeast Brazil” (M.B. Silva, A.L. Amor, L.N. Santos, A.A. Galvão, A.V. Oviedo Vera, E.S. Silva et al., 2016) [1].

The accurate description of the nonlinear structural behaviour is an important issue in engineering science. Usually, classic nonlinear theories, such as fracture and damage mechanics, applied to finite element programmes are used to fulfil that purpose. Classic fracture mechanics describes the structural deterioration process by a few discrete cracks. This theory presents good precision for structures with simple geometries, few cracks and homogeneous materials. Classic damage mechanics measures the deterioration process by an internal variable called damage. This theory has been successful in the description of several deterioration mechanisms in continuum media. Despite their accuracy, classic fracture and damage mechanics present some drawbacks. Firstly, regarding civil engineering problems, both theories are not suitable for some practical applications. Secondly, fracture mechanics demands the consideration of initial cracks to begin the analysis. Lastly, classic damage models may present an issue known as localisation, what essentially leads to ill-posed problems and mesh-dependent numerical algorithms. Alternatively, a recent theory, called lumped damage mechanics, was proposed in order to achieve good accuracy in actual engineering problems. Such theory applies key concepts from fracture and damage mechanics in plastic hinges. In the light of the foregoing, the main goal of this thesis is the extension of the lumped damage mechanics framework to analyse different engineering problems. So far, lumped damage mechanics was characterised as a simplified methodology to analyse reinforced concrete frames under seismic and monotonic loadings; even with a few contributions on the analysis of local buckling in metallic structures. Therefore, this work extends the lumped damage mechanics framework to analyse reinforced concrete arches, unreinforced concrete structures, high cycle fatigue and continuum problems. The application examples show the accuracy of the proposed methodologies. A descrição acurada do comportamento não linear de estruturas é um problema importante na engenharia. Usualmente, teorias não lineares clássicas, tais como as mecânicas da fratura e do dano, aplicadas a programas de elementos finitos são utilizadas a fim de cumprir aquele propósito. A mecânica da fratura clássica descreve o processo de deterioração estrutural por meio de um pequeno número de fissuras discretas. Esta teoria apresenta boa precisão para estruturas com geometrias simples, poucas fissuras e materiais homogêneos. A mecânica do dano clássica tem sido exitosa na descrição de diversos mecanismos de deterioração em meios contínuos. Apesar de precisas, as abordagens clássicas em fratura e dano apresentam alguns entraves. Primeiramente, tratando-se de problemas da engenharia civil, ambas teorias não são adequadas para aplicações práticas. Em segundo lugar, os modelos clássicos de fratura demandam a consideração de fissuras iniciais para iniciar a análise. Por fim, os modelos clássicos de dano podem apresentar um problema conhecido como localização, o que essencialmente implica em problemas mal colocados e algoritmos com dependência de malha. Alternativamente, uma teoria recente, chamada teoria do dano concentrado, foi proposta a fim de obter boa precisão em problemas reais de engenharia. Tal teoria aplica conceitos-chave das mecânicas da fratura e do dano em rótulas plásticas. À luz do exposto, o principal objetivo desta tese é a extensão da teoria do dano concentrado para analisar diferente problemas da engenharia. Até então, a teoria do dano concentrado era caracterizada como uma metodologia simplificada para analisar pórticos de concreto armado sob solicitações monotônicas ou sísmicas; mesmo com algumas poucas contribuições na análise de instabilidade local em estruturas metálicas. Desta forma, este trabalho estende a teoria do dano concentrado a fim de analisar arcos de concreto armado, estruturas de concreto simples, fadiga de alto ciclo e problemas contínuos. Os exemplos de aplicação mostram a acurácia das metodologias propostas.

Toxocara canis, Toxocara cati, are roundworms that live in the intestines of dogs and cats, respectively, and are predominantly agents of human toxocariasis. Studies have suggested that Toxocara spp. seroprevalence increases levels of total and aeroallergen-specific IgE (sIgE), asthma prevalence and asthma morbidity. Nevertheless, other work reported a negative association between Toxocara spp. seropositivity with skin hypersensititity and a positive association with sIgE. The objective of the present study was to evaluate risk factors for acquiring Toxocara spp. infection and to investigate possible significant association between its seroprevalence with atopy and asthma. Students from elementary schools, residents in a small town and its surroundings of Northeast Brazil, underwent blood sampling to measure levels of anti-Toxocara spp. IgG, peripheral blood eosinophils, and specific IgE to aeroallergens. We used univariable and multivariable logistic regression analyses to assess possible risk factors for Toxocara spp. seropositivity and its association with atopy, wheeze/asthma with asthma phenotypes, in a sample of 791 elementary school children aged 6-13 years. Toxocara spp. seroprevalence reached 63.6%; 49.9% had sIgE; 7.2% and 3.3% had atopic wheeze/asthma and non-atopic wheeze/asthma respectively. Risk factors associated with Toxocara spp. seropositivity were: contact with dogs (adj. OR 2.33; 95% CI=1.70-3.19) and cats (adj. OR 3.09; 95% CI=2.10-4.55), and male sex (adj. OR 2.21; 95% CI=1.62-3.02). The presence of anti-Toxocara IgG was statistically associated with blood eosinophils >4% and >10% (adj. OR 1.84; 95% CI=1.33-2.55 and adj. OR 2.07; 95% CI=1.45-2.97, respectively), and atopy (adj. OR 2.00; 95% CI=1.49-2.68), but it was not associated with wheeze/asthma. Concluding, the results obtained in this study showing the association of Toxocara spp. seroprevalence with sIgE may suggest a possible immunological cross-reactivity between IgE epitopes from Toxocara spp. and aeroallergens.

Background : Restricted Environmental Stimulation Therapy (REST) promotes physiological and behavioral changes that reduce the deleterious effects of stress. However, it requires expensive equipment and is accessible to a limited number of professionals and patients. We aimed to evaluate the physiological and behavioral effects of modified REST (mREST) in healthy young women. Method: Twenty-one healthy young women (20-25 yrs) participated. mREST consists of positioning the patient floating in the pool with 32 o C for about 15 minutes, for twelve sessions, with blindfolded and wearing earplugs. The evaluation was performed before and after the intervention. The analysis of the state of relaxation was investigated by a questionnaire and the self-reports were categorized. Measures of heart rate and blood pressure were used as indicators of the cardiovascular response. Flexibility, measured by the finger-to-floor test, was used as an indicator of muscle relaxation. Results : Heart rate and blood pressure significantly decreased while flexibility and relaxation increased after the sessions (p

Aim: This study's objective was to investigate whether candidin or trichophytin elicit recall immune responses that could potentially inhibit a Th2 response. Materials & methods: Peripheral blood mononuclear cells from nine allergic and seven nonallergic individuals were cultivated in vitro in the presence or absence of these fungal extracts. Results: Trichophytin or candidin, or both, stimulated the production of regulatory cytokines (TGF-β and/or IL-10), accompanied or not by stimulation of production of cytokines associated with the Th1 response (TNF-α, IL-12 and IFN-γ), but without stimulation of Th2 cytokines (IL-5 and IL-13) and IL-17, by peripheral blood mononuclear cells of most allergic and nonallergic individuals. Conclusion: These results indicate that these fungal extracts could be used as adjuvants in personalized therapeutic vaccines in a fair proportion of individuals. In addition, they justify the carrying out of investigations aimed at identifying molecules in these extracts that might exclusively induce Treg and/or Th1 immune responses.

Submitted by ROBERTO PAULO CORREIA DE ARAÚJO (ppgorgsistem@ufba.br) on 2017-06-02T14:45:12Z No. of bitstreams: 1 14_v.9_1.pdf: 122550 bytes, checksum: 1b6e55af84b0a498c238591e18903c2d (MD5) Made available in DSpace on 2017-06-02T14:45:12Z (GMT). No. of bitstreams: 1 14_v.9_1.pdf: 122550 bytes, checksum: 1b6e55af84b0a498c238591e18903c2d (MD5) Previous issue date: 2010-01 As doenças cardiovasculares são as maiores causadoras de óbitos no mundo, e o aumento do LDL (lipoproteína de baixa densidade) é apontado como um dos fatores de risco mais importantes para essas doenças. Hoje em dia, as estatinas são os fármacos mais potentes e eficazes na diminuição do LDL, mas apesar de seus efeitos potencialmente benéficos, elas devem ser administradas com precaução, já que também apresentam efeitos colaterais. O objetivo deste trabalho foi fazer uma revisão de literatura que buscasse elucidar os mecanismos dos efeitos adversos causados pelas estatinas e as evidências clínicas destes efeitos. Os mecanismos bioquímicos e celulares da toxicidade muscular, hepática e neuronal estão abordados. Em suma, os efeitos terapêuticos das estatinas, assim como os efeitos adversos, ocorrem devido à inibição da síntese de moléculas dependentes da enzima HMG-CoA-redutase, tais como o mevalonato e isoprenóides. O real panorama de ocorrência das reações adversas e uma breve comparação entre as estatinas utilizadas terapeuticamente também são apresentados. Salvador

A simplified model of cracking and damage in RC circular elements is proposed. The model can be used for the structural assessment of arches and rings. The constitutive equations are based on lumped damage mechanics which is an adaptation of fracture and continuum damage mechanics to the theory of frames with plastic hinges. An arch element is assumed to be the assemblage of an elastic circular component and two inelastic hinges where the main inelastic effects, plastic yielding of the longitudinal reinforcement and concrete cracking, are concentrated. Deformations in the elastic part are assumed to be small but the model may include some geometrically nonlinear effects due to large displacements or rotations of the hinges. The numerical examples presented in the paper show that the model describes correctly the global behavior of two structures including the softening phase.