147 research outputs found

    A parametric study on a RC frame based on “PUSHOVER” analysis

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    Three commercial software packages (SAP 2000, SeismoStruck and MIDAS/CIVIL) universally used in the design of civil engineering structures, are applied on a parametric study of pushover analyses of a RC frame of an office building under a few evaluative phases. In order to represent the influence of the masonry infill panels the equivalent tie method is used; for a sensitivity study on the capacity curves, several values for the tie width are considered. The comprehensive parametric study also addresses the influence of other parameters, on the structural behavior and non linear capacity curves of the RC frame, namely: length and location of the plastic hinges forming near the end of the structural elements, and different loading patterns (with uniform, modal and triangular distributions)

    Expected Response To Early-generation Selection For Yield And Tuber Appearance Traits In Potatoes

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    The aim of this study was to evaluate the performance of potato clonal families, and to estimate genetic variance, heritability and the expected response to selection of tuber yield and appearance traits in early generations. Twelve potato families were obtained from crosses between two groups of randomly-selected genotypes, including Eliza, C1730-7-94, and C1742-8-95 in group 1; and Shepody, Asterix, Caesar, and White Lady in group 2. The crosses were made in factorial design (3 genotypes x 4 genotypes), and each family consisted of 75 genotypes. Experiments were conducted in the fall of 2010, with a seedling generation under greenhouse conditions, and in the fall of 2011, with a clonal generation under field condition. High heritability estimates suggest that mild to moderate selection can be applied in the seedling generation to eye depth, eyebrow prominence, tuber curvature, flattening and shape uniformity. The C1742-8-95/White Lady stood out as a superior cross, as did all other crosses with White Lady, regarding tuber appearance and yield traits.3752849285

    Soil biochemistry and microbial activity in vineyards under conventional and organic management at Northeast Brazil.

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    The São Francisco Submedium Valley is located at the Brazilian semiarid region and is an important center for irrigated fruit growing. This region is responsible for 97% of the national exportation of table grapes, including seedless grapes. Based on the fact that orgThe São Francisco Submedium Valley is located at the Brazilian semiarid region and is an important center for irrigated fruit growing. This region is responsible for 97% of the national exportation of table grapes, including seedless grapes. Based on the fact that organic fertilization can improve soil quality, we compared the effects of conventional and organic soil management on microbial activity and mycorrhization of seedless grape crops. We measured glomerospores number, most probable number (MPN) of propagules, richness of arbuscular mycorrhizal fungi (AMF) species, AMF root colonization, EE-BRSP production, carbon microbial biomass (C-MB), microbial respiration, fluorescein diacetate hydrolytic activity (FDA) and metabolic coefficient (qCO2). The organic management led to an increase in all variables with the exception of EE-BRSP and qCO2. Mycorrhizal colonization increased from 4.7% in conventional crops to 15.9% in organic crops. Spore number ranged from 4.1 to 12.4 per 50 g-1 soil in both management systems. The most probable number of AMF propagules increased from 79 cm-3 soil in the conventional system to 110 cm-3 soil in the organic system. Microbial carbon, CO2 emission, and FDA activity were increased by 100 to 200% in the organic crop. Thirteen species of AMF were identified, the majority in the organic cultivation system. Acaulospora excavata, Entrophospora infrequens, Glomus sp.3 and Scutellospora sp. were found only in the organically managed crop. S. gregaria was found only in the conventional crop. Organically managed vineyards increased mycorrhization and general soil microbial activity

    Quantification of structure–property relationships for plant polyesters reveals suberin and cutin idiosyncrasies

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    Polyesters, as they exist in planta, are promising materials with which to begin the development of “green” replacements. Cutin and suberin, polyesters found ubiquitously in plants, are prime candidates. Samples enriched for plant polyesters, and in which their native backbones were largely preserved, were studied to identify “natural” structural features; features that influence critical physical properties. Quantitative nuclear magnetic resonance (NMR), differential scanning calorimetry (DSC), and X-ray scattering methods were used to quantify structure–property relationships in these polymeric materials. The degree of esterification, namely, the presence of acylglycerol linkages in suberin and of secondary esters in cutin, and the existence of mid-chain epoxide groups defining the packing of the aliphatic chains were observed. This packing determines polymer crystallinity, the resulting crystal structure, and the melting temperature. To evaluate the strength of this rule, tomato cutin from the same genotype, studying wild-type plants and two well-characterized mutants, was analyzed. The results show that cutin’s material properties are influenced by the amount of unbound aliphatic hydroxyl groups and by the length of the aliphatic chain. Collectively, the acquired data can be used as a tool to guide the selection of plant polyesters with precise structural features, and hence physicochemical properties

    Design procedures of reinforced concrete framed buildings in Nepal and its impact on seismic safety

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    The present paper analyses the design procedure and its impact on seismic safety of the structures. For this, a representative reinforced concrete frame building (WDS) is designed and the results are compared with similar buildings detailed with: i) Current Construction Practices (CCP); ii) the Nepal Building Code (NBC) and iii) the Modified Nepal Building Code (NBC+) recommendations. The seismic performance evaluation is done with global strength, inter-storey drift and displacement of the structures. Likewise, the sensitivity of the structural and geometrical parameters of the RC frame building is studied through nonlinear analysis. The study parameters considered for parametric analysis are column size, beam size, inter-storey height, bay length, bay width, and compressive strength of concrete. The results show that the influence on the structural behaviour, particularly by variation in column size and inter-storey height. Additionally, the influence of the seismic zone factor on reinforcement demand of the structure is studied. The result shows that structures designed for high to medium seismic hazard demands double the reinforcement in beams compared to structures in low seismic zone
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