334 research outputs found

    Seismic performance assessment of conventional steel and steel-concrete composite moment frames using CFST columns

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    [EN] The research reported in this paper focuses on the assessment of the seismic performance of conventional steel moment-resisting frames (MRFs) and steel-concrete composite moment-resisting frames employing circular Concrete-Filled Steel Tube (CFST) columns. Two comparable archetypes (i.e. one steel MRF, with steel columns and steel beams; and one composite MRF, with circular CFST columns and steel beams) are designed, and used as the basis for comparison between the seismic performance associated with each typology. Both structures are designed against earthquake loads following the recommendations of Eurocode 8. The comparison of the obtained design solutions allows concluding that the amount of steel associated with the main structural members is higher for the steel-only archetype, even though the composite MRF has the higher level of lateral stiffness. This aspect is particularly relevant when one considers that a minimum level of lateral stiffness (associated with the P-Δ inter-storey drift sensitivity coefficient, θ), is imposed by the European code, which may ultimately govern the design process. The two case-studies are then numerically modelled in OpenSees, and their seismic performance is assessed through fragility assessment for a number of relevant limit states, and, finally, earthquake-induced loss estimation. In general, the results obtained clearly indicate that the composite MRF with circular CFST columns exhibits better seismic performance than the equivalent steel-only archetype. This is noticeably shown in the comparison of the fragility curves associated with the collapse limit state, which tend to show substantially higher probabilities of exceedance, at similar levels of 1st-mode spectral acceleration, for the steel-only case. Furthermore, seismic losses at several seismic intensity levels of interest tend to be higher for the steel MRF.Silva, A.; Jiang, Y.; Macedo, L.; Castro, JM.; Monteiro, R. (2018). Seismic performance assessment of conventional steel and steel-concrete composite moment frames using CFST columns. En Proceedings of the 12th International Conference on Advances in Steel-Concrete Composite Structures. ASCCS 2018. Editorial Universitat Politècnica de València. 685-692. https://doi.org/10.4995/ASCCS2018.2018.7165OCS68569

    FEASIBILITY OF EARLY Pinus taeda L. SELECTION TO ASSESS GROWTH VARIABLES IN PROGENY TEST

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    Forest species breeding programs require a long period-of-time for plants to reach the proper age to enable selecting superior genotypes, which is a critical factor in selection processes. Thus, the aims of the current study are to estimate genetic parameters in juvenile and adult plants (6, 10 and 20 years) in order to investigate genetic correlations between variables at different ages and at certain ages; as well as to determine whether it is possible performing efficient early selection in juvenile plants. The test was implemented in 1997; it comprised 120 progenies and followed a randomized block design, with five repetitions - linear plots comprised 5 plants at 2.5 m x 2.5 m spacing. DBH (cm), H (m) and VOL (m³) of all tested subjects were measured at the age of 6, 10 and 20 years. Variance components, genetic parameters, as well as genetic correlations between variables and between ages were estimated in Selegen REML/BLUP® software. Genetic parameter estimates have shown superiority at 10 years, in comparison to that estimated at 6 and 20 years. Variable ‘DBH’ has shown high genetic correlation to height (H) and volume (VOL), whereas DBH x VOL have shown high genetic correlation (0.98) in 10-year-old plants. With respect to genetic correlation between ages, 10-year-old plants have shown moderate correlation to 6- and 20-year-old plants. Early selection is indicated for 10-year-old plants, in 20-year cycles, since plants at this age have shown higher selection efficiency to predict gains in comparison to adult plants

    Multipoverty in Venezuela

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    Poverty has been defined by several authors and international organizations from similar perspectives. However, those definitions tend to be simplistic and not powerful enough to deal with complex situations that involve different points of view on the poverty phenomenon. The aim of this paper is to use a praxeological standpoint and introduce a new definition, multipoverty, while using it to analyze the current crisis in Venezuela. Three main conclusions are drawn: in current Venezuela, all common people are very likely to be poor, and a social explosion there is possible; the nature of the human being is too complex to be analyzed under a simplistic approach based on the rigidness of pure quantitative methods; the multipoverty approach adds a humanistic, praxeological, and individualistic edge, based upon ideas of freedom of action, to the traditional definitions of poverty and helps to better understand the phenomena

    Cardiovascular responses to passive static flexibility exercises are influenced by the stretched muscle mass and the Valsalva maneuver

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    BACKGROUND: The respiratory pattern is often modified or even blocked during flexibility exercises, but little is known about the cardiovascular response to concomitant stretching and the Valsalva maneuver (VM) in healthy subjects. OBJECTIVES: This study evaluated the heart rate (HR), systolic blood pressure (SBP), and rate-pressure product (RPP) during and after large and small muscle group flexibility exercises performed simultaneously with the VM. METHODS: Asymptomatic volunteers (N = 22) with the following characteristics were recruited: age, 22 ± 3 years; weight, 73 ± 6 kg; height, 175 ± 5 cm; HR at rest, 66 ± 9 BPM; and SBP at rest, 113 ± 10 mmHg. They performed two exercises: four sets of passive static stretching for 30 s of the dorsi-flexion (DF) of the gastrocnemius and the hip flexion (HF) of the ischio-tibialis. The exercises were performed with (V+) or without (V-) the VM in a counterbalanced order. The SBP and HR were measured, and the RPP was calculated before the exercise session, at the end of each set, and during a 30-min post-exercise recovery period. RESULTS: The within-group comparisons showed that only the SBP and RPP increased throughout the sets (p<0.05), but no post-exercise hypotension was detected. The between-group comparisons showed that greater SBP increases were related to the VM and to a larger stretched muscle mass. Differences for a given set were identified for the HR (the HFV+ and HFV- values were higher than the DFV+ and DFV- values by approximately 12 BPM), SBP (the HFV+ value was higher than the DFV+ and DFV- values by approximately 12 to 15 mmHg), and RPP (the HFV+ value was higher than the HFV- value by approximately 2000 mmHGxBPM, and the HFV+ value was higher than the DFV+ and DFV- values by approximately 4000 mmHGxBPM). CONCLUSION: Both the stretched muscle mass and the VM influence acute cardiovascular responses to multiple-set passive stretching exercise sessions

    Caracterização do pão regional do distrito de Viseu e de Pão São

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    Dissertação de Mestrado em Qualidade e Tecnologia AlimentarO objectivo deste estudo visa a caracterização de diferentes amostras de pão Regional e pão São, procurando encontrar semelhanças e identificar os elementos diferenciadores dos mesmos. As amostras de pão Regional foram recolhidas no distrito de Viseu: Carregal do Sal, Cabanas de Viriato, Santar, Viseu, Mangualde, São Pedro do Sul e São Cipriano. No caso do pão São as amostras foram fornecidas pela empresa produtora, Fábrica do Pão localizada em Seia. Procedeu-se à caracterização física, química e sensorial, tendo sido avaliadas as diferentes propriedades em termos de média e desvio padrão das réplicas efectuadas. Posteriormente, procedeu-se a uma análise estatística, para comparação de médias e avaliação da significância das diferenças, tendo para tal sido usado o teste de Tuckey HSD. Foram ainda calculados os coeficientes de correlação de Pearson. Os resultados foram analisados recorrendo ao software SPSS para o Windows versão 19.0 e Statistic versão 6., sendo realizado o teste de análise de variância "one-way" (ANOVA). Numa fase posterior, os valores obtidos para as características do pão foram sujeitos a uma análise de componentes principais (PCA) e uma análise de Cluster. Em relação aos parâmetros químicos analisados no pão Regional, as amostras apresentaram algumas semelhanças e algumas diferenças, assim como também a nível físico e sensorial. No entanto, no que respeita à análise sensorial, as amostras foram, de modo geral, percepcionadas da mesma forma pelos provadores, não sendo detectadas diferenças significativas. Ainda assim, em termos de apreciação global a amostra preferida foi a da pastelaria Flor de Cabanas. Em relação aos parâmetros químicos, físicose sensoriais do pão São, as amostras mostraram-se semelhantes entre si, o que pode ser explicado por terem basicamente a mesma constituição em termos de ingredientes. Contudo, será de assinalar algumas diferenças em termos de fibra, hidratos de carbono, proteína e cloretos, devido à presença de farinha de tremoço numa das amostras. Quando comparadas as amostras de pão Regional com as de pão São, verificou-se que estas se apresentaram bastante diferentes, quer em termos químicos, físicos ou nível sensorial. Foi possível observar que ao nível sensorial os pães Regionais foram os preferidos pelos provadores.ABSTRACT: The aim of this study is the characterization of different samples of regional bread and healthy bread, trying to identify the similarities and contrasting elements in them. The regional bread samples were collected in the District of Viseu: Carregal do Sal, Cabanas de Viriato, Santar, Viseu, São Pedro do Sul and São Cipriano. The healthy bread samples were provided by the production company "Fábrica do Pão", located in Seia. The physical, chemical and sensory characterization was undertaken, having been avaluted the different proprerties in terms of mean value and standard deviation of the replicas made. Later, we proceeded to a statistical analysis for comparison of means and assessing the significance of the differences, having been used for this the Tukey HSD test. We also calculated the Pearson correlation coefficients. The results were analyzaed using the SPSS software version 19.0 for Windows and Statistica version 6, having been performed an analysis of variance "one way"(ANOVA). At a later stage, the values obtained for the characteristics of bread were subjected to principal components analysis (PCA) and cluster analysis. Regardind the chemical parameters analyzed in the regional bread, the samples showed some similarities and differences, as well as regarding the physical and sensory parameters. However, concerning the sensory analysis, the samples were generally perceived by the panelists in the same way, and no significant differences were observed. Still, in terms of the same way preferred by the panelists the sample from pastry "Flor de Cabanas". With respect to chemical, physical and sensory parameters of the healthy bread, the samples were similar, which can be explained by having basically the same constitution in terms of ingredients. However, there can be noted some differences in terms of fiber, carbohydrates, protein and chlorides, due to the presence of lupine flour in one sample. When comparing the regional bread samples with the healthy bread ones, it was found that they quite different, either at the chemical, physical or sensory levels. It was observed that at the sensory level the regional breads were those preferred by the tasters

    Increasing Acid Concentration, Time and Using a Two-Part Silane Potentiates Bond Strength of Lithium Disilicate-Reinforced Glass Ceramic to Resin Composite:An Exploratory Laboratory Study

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    There is still a lack of consensus concerning the recommended etching concentration, application time and type of silane when bonding lithium disilicate-reinforced glass ceramics manufactured by CAD/CAM. The purpose of this study was thus to conduct an in vitro study which investigates the influence of hydrofluoric acid (HF) concentration, etching time and silane type on the microtensile bond strength (μTBS) of lithium disilicate to resin composites. Thirty-nine IPS e.max CAD blocks were randomly divided between thirteen groups (n = 3). The variables were HF concentration (9.5 or 4.9%), etching time (20 or 60 s) and silane type (Bis-Silane, Monobond Plus and ESPE Sil Silane). The blocks were cut into beams, aged for 10,000 cycles in a thermocycler and submitted to tensile stress to determine μTBS. A control group featuring the Monobond Etch & Prime (MEP) agent that combines etching/silanisation into a simultaneous process was also added. This group was discarded from the analysis due to only having pre-test failures. The data were analysed using a three-way ANOVA (α = 0.05). The HF concentration, etching time and silane type significantly influenced μTBS (p < 0.001). Significant interactions between time and silane type (p = 0.004), HF concentration and silane type (p < 0.001) and among the three factors (p < 0.001) were noted. Etching lithium disilicate with 9.5% HF (60 s), followed by the application of Bis-Silane, resulted in the highest μTBS (16.6 ± 9.0 MPa). The highest concentration and etching time under study, combined with a two-part silane, resulted in the highest bond strength, while the application of MEP showed a complete pre-test failure

    Web-GIS approach to preventive conservation of heritage buildings

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    The effective implementation of preventive conservation approaches demands the employment of standardized and robust tools able to integrate the data coming from multiple sources, inspection and diagnosis techniques, as well as to ensure the proper information transfer between expert and non-expert users. Aiming to make a step forward in the state of the art of current conservation approaches, a cutting edge Web-GIS technology resorting to the intuitiveness of 360° panoramas and 3D point clouds in combination with the Internet of Things is presented in this work, demonstrating how physical and digital worlds can be linked for proper documentation and management of cultural heritage. To validate such a pioneering approach, one of the most representative and complex heritage buildings of Spain is used as a case study: the General Historical Library of Salamanca.This work was financed by ERDF funds through the V Sudoe Interreg program within the framework of the HeritageCare project (Ref. SOE1/P5/P0258), by project Patrimonio 5.0 (SA075P17), by FEDER funds through the Competitive Factors Operational Program (COMPETE) and by the Foundation for Science and Technology (FCT) within the scope of projects POCI-01-0145-FEDER-007633. The authors would like to express their gratitude to the personnel from the General Historical Library of the University of Salamanca as well as to the Centre for Computer Graphics of the University of Minho for the web implementation of the platform

    AGRUPAMENTO DE FAMÍLIAS DE MEIO-IRMÃOS DE Pinus taeda BASEADO EM CARACTERÍSTICAS FÍSICAS E MECÂNICAS DA MADEIRA

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    Este trabalho teve como objetivo agrupar famílias de um teste de progênies de Pinus taeda L. com base nas propriedades físicas e mecânicas da madeira, para inclusão dessas características qualitativas da madeira em um programa de melhoramento genético. As variáveis analisadas foram: massa específica básica e aparente, coeficientes de contração máxima volumétrica e linear tangencial, radial e longitudinal, anisotropia de contração e coeficientes de retratibilidade volumétrico, tangencial e radial, MOE, MOR e tensão de cisalhamento. As árvores avaliadas pertenciam a um teste de progênies instalado em blocos casualizados com cinco repetições, 120 famílias. Dentre as cinco plantas por parcela foi amostrada uma. Foram coletados os discos base, 25%, 50%, 75% e 100% da altura, para determinação da massa específica básica. A primeira e segunda toras foram utilizadas na preparação de amostras para as demais análises físicas e mecânicas. Na análise do experimento, foi utilizada a análise de componentes principais e de agrupamento. A análise de componentes principais permitiu destacar seis autovalores, explicando 82,51% da variância total das observações, e a análise de agrupamento possibilitou o agrupamento das 120 famílias em seis grupos, os quais apresentam distintas características de qualidade da madeira relacionadas à produção para diferentes finalidades.This research aimed to gather families of a Pinus taeda L. progeny test based on physical and mechanical properties of wood, in order to include these wood characteristics in a breeding program. The variables focused were: specific gravity and apparent maximum volumetric shrinkage coefficients and linear tangential, radial and longitudinal shrinkage anisotropy coefficients and volumetric shrinkage, the tangential and radial MOE and MOR and shear stress. Trees evaluated were sampled (one plant per plot) in a progeny test planted in randomized blocks with 120 families, five replicates, and five plants per linear plot. After measuring the DBH on standing trees the discs were collected to evaluate the specific gravity, on the following positions: base, 25%, 50%, 75% and 100% of the commercial height. The first and second logs were used for sample preparation for other physical and mechanical analysis. The principal component analysis allowed to highlight six eigenvalues which explained 82.51% of the total observations variance, and cluster analysis allowed 120 families gathering in six groups, which have different quality characteristics related to production of wood for different purposes

    INFLUÊNCIA DE DIFERENTES SÍTIOS DE CRESCIMENTO SOBRE A QUALIDADE DA MADEIRA DE Pinus taeda

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    The present paper analyzes the effects of different growing sites and spacings on the quality of the Pinus taeda wood, as well as testing the non-destructive technique of stress wave application for estimating wood properties. Three sites containing 14, 16 and 18-year-old trees were analyzed. For site characterization undisturbed and compound soil samples were collected. In each site, five trees were selected. On these standing trees measurements of propagation time of stress waves, total and commercial height as well as the breast height diameter were measured and discs were taken from five different positions along the trunk. Afterwards, measurements of propagation time of stress waves were done on these newly cut logs. Needles were also collected from the middle third of each tree. In relation to the growing sites in general, the wood that comes from fast growing rate sites showed higher value for specific mass, shorter and broader fibers with a larger diameter and thicker walls and, consequently, higher values for Runkel index and fraction wall and lower values for coefficient of flexibility and felting index. Significant correlations were detected, thus showing that the technique can be applied for indirect estimate (non-destructive) of these properties.O presente trabalho analisa os efeitos de diferentes sítios de crescimento na qualidade da madeira de Pinus taeda, além de testar a técnica não-destrutiva de aplicação de ondas de tensão para estimativa das características da madeira. Foram analisados três sítios com árvores de 14, 16 e 18 anos de idade. Para a caracterização do sítio, foram coletadas amostras de solo indeformadas e compostas. Em cada sítio foram selecionadas cinco árvores. Com elas ainda em pé, foram realizadas medições do tempo de propagação de ondas de tensão. Também foram medidos a altura total e comercial e o diâmetro à altura do peito, e retirados discos em cinco posições ao longo do fuste. Posteriormente, nas toras recém-abatidas, efetuaram-se novamente as medições do tempo de propagação das ondas de tensão, além de serem coletadas acículas do terço médio da copa de cada árvore. De maneira geral, as madeiras provenientes de sítios com taxa de crescimento elevado apresentaram maiores valores para massa específica, fibras mais curtas, mais largas, com diâmetros maiores e paredes mais espessas – conseqüentemente, maiores valores para índice de Runkel e fração parede e menores valores para coeficiente de flexibilidade e índice de enfeltramento. Correlações significativas foram detectadas, indicando que a técnica não-destrutiva pode ser empregada para determinação indireta dessas características

    EFICIÊNCIA ENERGÉTICA E TRATAMENTO DE RESÍDUOS APLICADO À SERRARIA DE QUARTZITO NA PARAÍBA

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    Com o crescimento acentuado da construção civil, o comércio de rochas ornamentais sofreu um forte aumento nos últimos anos, dentre estas está inserido o Quartzito. Rocha com suas particularidades características e de variadas aplicabilidades, é encontrada em diversas cores e em abundância no município de Junco do Seridó na Mesorregião do estado da Paraíba. Com o aumento do beneficiamento do Quartzito, consequentemente, tem acrescido a quantidade de resíduos gerados e a problemática de sua destinação correta. A busca da reutilização desses resíduos no processo produtivo das fabricas que beneficiam essas rochas vem aumentado, tanto pelo incremento econômico quanto pela preservação ambiental. Desta forma, neste trabalho objetiva-se caracterizar os resíduos gerados no beneficiamento do Quartzito e propor soluções de tratamento e alternativas de aplicabilidade para estes
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