947 resultados para Negative stiffness structure, snap through, elastomers, hyperelastic model, root cause analysis


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Methods for understanding classical disordered spin systems with interactions conforming to some idealized graphical structure are well developed. The equilibrium properties of the Sherrington-Kirkpatrick model, which has a densely connected structure, have become well understood. Many features generalize to sparse Erdös- Rényi graph structures above the percolation threshold and to Bethe lattices when appropriate boundary conditions apply. In this paper, we consider spin states subject to a combination of sparse strong interactions with weak dense interactions, which we term a composite model. The equilibrium properties are examined through the replica method, with exact analysis of the high-temperature paramagnetic, spin-glass, and ferromagnetic phases by perturbative schemes. We present results of replica symmetric variational approximations, where perturbative approaches fail at lower temperature. Results demonstrate re-entrant behaviors from spin glass to ferromagnetic phases as temperature is lowered, including transitions from replica symmetry broken to replica symmetric phases. The nature of high-temperature transitions is found to be sensitive to the connectivity profile in the sparse subgraph, with regular connectivity a discontinuous transition from the paramagnetic to ferromagnetic phases is apparent.

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The design and implementation of data bases involve, firstly, the formulation of a conceptual data model by systematic analysis of the structure and information requirements of the organisation for which the system is being designed; secondly, the logical mapping of this conceptual model onto the data structure of the target data base management system (DBMS); and thirdly, the physical mapping of this structured model into storage structures of the target DBMS. The accuracy of both the logical and physical mapping determine the performance of the resulting systems. This thesis describes research which develops software tools to facilitate the implementation of data bases. A conceptual model describing the information structure of a hospital is derived using the Entity-Relationship (E-R) approach and this model forms the basis for mapping onto the logical model. Rules are derived for automatically mapping the conceptual model onto relational and CODASYL types of data structures. Further algorithms are developed for partly automating the implementation of these models onto INGRES, MIMER and VAX-11 DBMS.

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Self-similar optical pulses (or “similaritons”) of parabolic intensity profile can be found as asymptotic solutions of the nonlinear Schr¨odinger equation in a gain medium such as a fiber amplifier or laser resonator. These solutions represent a wide-ranging significance example of dissipative nonlinear structures in optics. Here, we address some issues related to the formation and evolution of parabolic pulses in a fiber gain medium by means of semi-analytic approaches. In particular, the effect of the third-order dispersion on the structure of the asymptotic solution is examined. Our analysis is based on the resolution of ordinary differential equations, which enable us to describe the main properties of the pulse propagation and structural characteristics observable through direct numerical simulations of the basic partial differential equation model with sufficient accuracy.

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Classification is the most basic method for organizing resources in the physical space, cyber space, socio space and mental space. To create a unified model that can effectively manage resources in different spaces is a challenge. The Resource Space Model RSM is to manage versatile resources with a multi-dimensional classification space. It supports generalization and specialization on multi-dimensional classifications. This paper introduces the basic concepts of RSM, and proposes the Probabilistic Resource Space Model, P-RSM, to deal with uncertainty in managing various resources in different spaces of the cyber-physical society. P-RSM’s normal forms, operations and integrity constraints are developed to support effective management of the resource space. Characteristics of the P-RSM are analyzed through experiments. This model also enables various services to be described, discovered and composed from multiple dimensions and abstraction levels with normal form and integrity guarantees. Some extensions and applications of the P-RSM are introduced.

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Self-similar optical pulses (or “similaritons”) of parabolic intensity profile can be found as asymptotic solutions of the nonlinear Schr¨odinger equation in a gain medium such as a fiber amplifier or laser resonator. These solutions represent a wide-ranging significance example of dissipative nonlinear structures in optics. Here, we address some issues related to the formation and evolution of parabolic pulses in a fiber gain medium by means of semi-analytic approaches. In particular, the effect of the third-order dispersion on the structure of the asymptotic solution is examined. Our analysis is based on the resolution of ordinary differential equations, which enable us to describe the main properties of the pulse propagation and structural characteristics observable through direct numerical simulations of the basic partial differential equation model with sufficient accuracy.

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The cross-country petroleum pipelines are environmentally sensitive because they traverse through varied terrain covering crop fields, forests, rivers, populated areas, desert, hills and offshore. Any malfunction of these pipelines may cause devastating effect on the environment. Hence, the pipeline operators plan and design pipelines projects with sufficient consideration of environment and social aspects along with the technological alternatives. Traditionally, in project appraisal, optimum technical alternative is selected using financial analysis. Impact assessments (IA) are then carried out to justify the selection and subsequent statutory approval. However, the IAs often suggest alternative sites and/or alternate technology and implementation methodology, resulting in revision of entire technical and financial analysis. This study addresses the above issues by developing an integrated framework for project feasibility analysis with the application of analytic hierarchy process (AHP), a multiple attribute decision-making technique. The model considers technical analysis (TA), socioeconomic IA (SEIA) and environmental IA (EIA) in an integrated framework to select the best project from a few alternative feasible projects. Subsequent financial analysis then justifies the selection. The entire methodology has been explained here through a case application on cross-country petroleum pipeline project in India.

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This dissertation presents an analysis of the impacts of trade policy reforms in Sri Lanka. A Computable General Equilibrium (CGE) model is constructed with detailed description of the domestic production structure and foreign trade. The model is then used to investigate the effects of trade policy reforms on resource allocation and welfare.^ Prior to 1977, Sri Lanka maintained stringent control over its imports through rigid quantitative restrictions. A new economic policy reform package was introduced in 1977, and it shifted Sri Lanka's development strategy toward an export oriented policy regime. The shift of policy focus from a restrictive trade regime toward a more open trade regime is expected to have a significant impact on the volume of external trade, domestic production structure, allocation of resources, and social welfare.^ Simulations are carried out to assess the effects of three major policy reforms: (1) a devaluation of the Sri Lanka rupee, (2) a partial or a complete elimination of export duties, and (3) a devaluation-cum-removal of export duties.^ Simulation results indicate that the macroeconomic impact of a devaluation-cum-removal of export duties can be substantial. They also suggest that the resource-pull effects of a devaluation and a devaluation-cum-export duty removal policy are significant. However, the model shows that a devaluation combined with an export duty reduction is likely to be a superior strategy. ^

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The purpose of this study was to document and critically analyze the lived experience of selected nursing staff developers in the process of moving toward a new model for hospital nursing education. Eleven respondents were drawn from a nation-wide population of about two hundred individuals involved in nursing staff development. These subjects were responsible for the implementation of the Performance Based Development System (PBDS) in their institutions.^ A purposive, criterion-based sampling technique was used with respondents being selected according to size of hospital, primary responsibility for orchestration of the change, influence over budgetary factors and managerial responsibility for PBDS. Data were gathered by the researcher through both in-person and telephone interviews. A semi-structured interview guide, designed by the researcher was used, and respondents were encouraged to amplify on their recollections as desired. Audiotapes were transcribed and resulting computer files were analyzed using the program "Martin". Answers to interview questions were compiled and reported across cases. The data was then reviewed a second time and interpreted for emerging themes and patterns.^ Two types of verification were used in the study. Internal verification was done through interview transcript review and feedback by respondents. External verification was done through review and feedback on data analysis by readers who were experienced in management of staff development departments.^ All respondents were female, so Gilligan's concept of the "ethic of care" was examined as a decision making strategy. Three levels of caring which influenced decision making were found. They were caring: (a) for the organization, (b) for the employee, and (c) for the patient. The four existentials of the lived experience, relationality, corporeality, temporality and spatiality were also examined to reveal the everydayness of making change. ^

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An integrated surface-subsurface hydrological model of Everglades National Park (ENP) was developed using MIKE SHE and MIKE 11 modeling software. The model has a resolution of 400 meters, covers approximately 1050 square miles of ENP, includes 110 miles of drainage canals with a variety of hydraulic structures, and processes hydrological information, such as evapotranspiration, precipitation, groundwater levels, canal discharges and levels, and operational schedules. Calibration was based on time series and probability of exceedance for water levels and discharges in the years 1987 through 1997. Model verification was then completed for the period of 1998 through 2005. Parameter sensitivity in uncertainty analysis showed that the model was most sensitive to the hydraulic conductivity of the regional Surficial Aquifer System, the Manning's roughness coefficient, and the leakage coefficient, which defines the canal-subsurface interaction. The model offers an enhanced predictive capability, compared to other models currently available, to simulate the flow regime in ENP and to forecast the impact of topography, water flows, and modifying operation schedules.

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The applicability of carbon-based foams as an insulating or active cooling material in thermal protection systems (TPSs) of space vehicles is considered using a computer modeling. This study focuses on numerical investigation of the performance of carbon foams for use in TPSs of space vehicles. Two kinds of carbon foams are considered in this study. For active cooling, the carbon foam that has a thermal conductivity of 100 W/m-k is used and for the insulation, the carbon foam having a thermal conductivity of 0.225 W/m-k is used. A 3D geometry is employed to simulate coolant flow and heat transfer through carbon foam model. Gambit has been used to model the 3D geometry and the numerical simulation is carried out in FLUENT. Numerical results from this thesis suggests that the use of CFOAM and HTC carbon foams in TPS's may effectively protect the aluminum structure of the space shuttle during reentry of the space vehicle.

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The search for new meanings in the basic education teaching-learning process has caused the development of public policies for mother language teaching, such as the Portuguese Language Olympics (OLP). To contribute to this search, this intervention project has as object of study reading and writing practices developed in the OLP through the educational model arising from literacy projects (TINOCO, 2008). In working towards, the general aim of reframing reading and writing practices through the PLO, developed from the teaching model that comes of literacy projects, we established three specific objectives: a) reflect on a national writing contest; b) to realign conceptual and methodological the Portuguese classes of the 7th grade school due to the developed project; c) to improve the reading and writing practices of the students in 7th grade of school where we operate. Therefore, we base ourselves in the history of Portuguese teaching in Brazil (SOARES, 2002; GERALDI, 2008), the dialogical conception of language (BAKHTIN, VOLOCHÍNOV [1929] 2009; SOARES, 1998; FARACO, 2009) in Literacy Studies (KLEIMAN, 2001, 2005, 2006; TINOCO, 2008; OLIVEIRA; TINOCO; SANTOS, 2011; STREET, 2014), the learning community concept (AFONSO, 2001), in studies of retextualization (OLIVEIRA, 2005; MARCUSCHI, 2010), gender discursive literary memories (CLARA; ALTENFELDER; ALMEIDA, 20--), in written evidence (POSSENTI, 2002) and Textual Linguistics (MARCUSCHI, 2008; ANTUNES, 2009; KOCH, 2011; SILVA [et. al.], 2013). Methodologically, this qualitative research (LÜDKE; ANDRÉ, 1986; ANDRÉ, 2005) is anchored in Applied Linguistics (MOITA LOPES, 1996). This research was supporting by students in the 7th grade, teachers, management team and parents, as well as people outside of school community. The instruments used for the generation of data were semi-structured interview, students‟ texts, audio recordings and video, photos, OLP material (teacher's book, a collection of texts and CD-ROM). The data generated allowed us to establish the following categories of analysis in relation to the texts produced: authorship, in formativeness, discursive progression, compositional structure, content, style, and language aspects. In addition, throughout the project, the collaborators have produced texts of various genres: oral interview and written request letter, legal, literary memories, oral and experience report. Also experienced a local award and participated in a national competition. They produced a video and a book with stories and student authorship of illustrations. The results achieved show that the literacy project developed also allowed macro changes: reading and writing practices, once considered strictly school studied, they were transformed into broader social practices, through which various literacy agents were able to collaboratively act. In short, they experienced writing practices that go beyond the classroom and the teacher-student relationship.

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Studies have shown that resident informally plays the role of teacher. It is estimated that up to 25% of the residents of the time is devoted to teaching, mainly contributing as a facilitator, however, almost the entire medical residency programs in Brazil did not offer teacher training during residency education. This paper aims to introduce educational content initiation to teaching as part of the training of resident physician inserted in residency program of the University Hospital Onofre Lopes (HUOL). It is an exploratory, descriptive and prospective study in HUOL the Federal University of Rio Grande do Norte. Three steps were developed: preparation and planning of a pedagogic course, associated with a motivating technical content (basic and advanced life support); second stage, testing of pedagogical model for medical students; and finally, replication to residents. The interventions were made two practice stations life support with performance evaluation in practical activity through OSPE (Objective Structured Practical Examination). The techniques presented teachings were one-minute preceptor and feedback. Data collection was conducted through a structured evaluation form during the life support stations and at the end of the course, and analyzed using descriptive statistics. The results showed that the feedback and one minute preceptor were considered important for teaching and learning for more than 85% of participants. The feedback from evaluators practices stations added information about the performance and were held appreciatively way, according to 100% of the participants. Positive aspects highlighted by the participants were related to educational content, especially the participants of the first intervention. The time of the lectures of motivating technical content was the most repeated negative. Based on the good acceptance of pedagogical contents, this pioneer teacher training strategy was included in the formal residency program in Cardiology of our institution. It is considered therefore that the educational training model with motivating technical content was feasible and had a good evaluation and acceptance by most participants in both interventions. Thus, we believe that the educational content can be inserted in the formal curriculum of medical residency of other programs at HUOL through the training model developed in this study.

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Studies have shown that resident informally plays the role of teacher. It is estimated that up to 25% of the residents of the time is devoted to teaching, mainly contributing as a facilitator, however, almost the entire medical residency programs in Brazil did not offer teacher training during residency education. This paper aims to introduce educational content initiation to teaching as part of the training of resident physician inserted in residency program of the University Hospital Onofre Lopes (HUOL). It is an exploratory, descriptive and prospective study in HUOL the Federal University of Rio Grande do Norte. Three steps were developed: preparation and planning of a pedagogic course, associated with a motivating technical content (basic and advanced life support); second stage, testing of pedagogical model for medical students; and finally, replication to residents. The interventions were made two practice stations life support with performance evaluation in practical activity through OSPE (Objective Structured Practical Examination). The techniques presented teachings were one-minute preceptor and feedback. Data collection was conducted through a structured evaluation form during the life support stations and at the end of the course, and analyzed using descriptive statistics. The results showed that the feedback and one minute preceptor were considered important for teaching and learning for more than 85% of participants. The feedback from evaluators practices stations added information about the performance and were held appreciatively way, according to 100% of the participants. Positive aspects highlighted by the participants were related to educational content, especially the participants of the first intervention. The time of the lectures of motivating technical content was the most repeated negative. Based on the good acceptance of pedagogical contents, this pioneer teacher training strategy was included in the formal residency program in Cardiology of our institution. It is considered therefore that the educational training model with motivating technical content was feasible and had a good evaluation and acceptance by most participants in both interventions. Thus, we believe that the educational content can be inserted in the formal curriculum of medical residency of other programs at HUOL through the training model developed in this study.

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The six-layered neuron structure in the cerebral cortex is the foundation for human mental abilities. In the developing cerebral cortex, neural stem cells undergo proliferation and differentiate into intermediate progenitors and neurons, a process known as embryonic neurogenesis. Disrupted embryonic neurogenesis is the root cause of a wide range of neurodevelopmental disorders, including microcephaly and intellectual disabilities. Multiple layers of regulatory networks have been identified and extensively studied over the past decades to understand this complex but extremely crucial process of brain development. In recent years, post-transcriptional RNA regulation through RNA binding proteins has emerged as a critical regulatory nexus in embryonic neurogenesis. The exon junction complex (EJC) is a highly conserved RNA binding complex composed of four core proteins, Magoh, Rbm8a, Eif4a3, and Casc3. The EJC plays a major role in regulating RNA splicing, nuclear export, subcellular localization, translation, and nonsense mediated RNA decay. Human genetic studies have associated individual EJC components with various developmental disorders. We showed previously that haploinsufficiency of Magoh causes microcephaly and disrupted neural stem cell differentiation in mouse. However, it is unclear if other EJC core components are also required for embryonic neurogenesis. More importantly, the molecular mechanism through which the EJC regulates embryonic neurogenesis remains largely unknown. Here, we demonstrated with genetically modified mouse models that both Rbm8a and Eif4a3 are required for proper embryonic neurogenesis and the formation of a normal brain. Using transcriptome and proteomic analysis, we showed that the EJC posttranscriptionally regulates genes involved in the p53 pathway, splicing and translation regulation, as well as ribosomal biogenesis. This is the first in vivo evidence suggesting that the etiology of EJC associated neurodevelopmental diseases can be ribosomopathies. We also showed that, different from other EJC core components, depletion of Casc3 only led to mild neurogenesis defects in the mouse model. However, our data suggested that Casc3 is required for embryo viability, development progression, and is potentially a regulator of cardiac development. Together, data presented in this thesis suggests that the EJC is crucial for embryonic neurogenesis and that the EJC and its peripheral factors may regulate development in a tissue-specific manner.

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Tropical Cyclones are a continuing threat to life and property. Willoughby (2012) found that a Pareto (power-law) cumulative distribution fitted to the most damaging 10% of US hurricane seasons fit their impacts well. Here, we find that damage follows a Pareto distribution because the assets at hazard follow a Zipf distribution, which can be thought of as a Pareto distribution with exponent 1. The Z-CAT model is an idealized hurricane catastrophe model that represents a coastline where populated places with Zipf- distributed assets are randomly scattered and damaged by virtual hurricanes with sizes and intensities generated through a Monte-Carlo process. Results produce realistic Pareto exponents. The ability of the Z-CAT model to simulate different climate scenarios allowed testing of sensitivities to Maximum Potential Intensity, landfall rates and building structure vulnerability. The Z-CAT model results demonstrate that a statistical significant difference in damage is found when only changes in the parameters create a doubling of damage.