Theoretical And Experimental Analysis Of Rhs/chs K Gap Joints [análise Teórico E Experimental De Ligações Tipo Rhs/chs Com Afastamento]

This work presents a study of welded K joints with gap, formed by a structural steel hot rolled hollow section, having rectangular hollow sections at the chords and circular hollow sections in the others members. The study developed theoretical and numerical analyses for the joints, experimental tests in full scale prototypes. Theoretical analyses were performed using code standards for K joints. The results in terms of behavior, ultimate load and collapse mode were analyzed and compared with numerical (finite elements) and theoretical models. The theoretical analysis was carried out from the code regulations. The joints tested indicated the failure mode of Plastic failure of the chord face (mode A). The results showed that the loads using code regulations and the ones from the numerical analysis had good agreement for the K joint.663295300(2007) Useŕs Manual For Revision 11. Swanson Analysis Systems Inc, , ANSYS, Houston, PA(2005) Design of Steel Structures - Structures - Part 1-8: General Rules and Rules For Buildings, p. 138. , Eurocode 3, Brussels: CEN, European Committee for StandardizationLu, L.H., Winkel, G.D., Yu, Y., Wardenier, J., Deformation limit for the strength of hollow sections joints (1994) International Symposium On Tubular Structures, pp. 341-347. , 6. Melbourne, AustraliaMayor, I.S., (2010) Análise Teórico-experimental De Ligações Tipo K E KT Compostas Por Perfis Tubulares De Seção Retangular E Circular, , Universidade Federal de Ouro Preto, Dissertação de Mestrado in portuguese)Nunes, G.V., (2012) Estudo Paramétrico De Ligações Tipo "T", "K"e "KT" Compostas Por Perfis Tubulares De Seção Retangular E Circular, , Universidade Federal de Ouro Preto, Dissertação de mestrado in portuguese)Mendanha, F.O., Freitas, A.M.S., Freitas, M.S.R., Muniz, C.D.G., Análise de ligações em perfis tubulares de aço do tipo K e KT com afastamento entre as diagonais e o montante (2007) REM - Revista Escola De Minas, 60 (2), pp. 419-426Mendes, F.C., Freitas, M.S.R., Freitas, A.M.S., Estudo teórico experimental de ligações T e KT em perfis tubulares (2012) REM - Revista Escola De Minas, 65 (2), pp. 175-180Packer, J.A., Wardenier, J., Zhao, X.-L., Van Der Vegte, G.J., Kurobane, Y., (2009) Design Guide - For Rectangular Hollow Section (RHS) Joints Under Predominantly Static Loading, p. 149. , 2nd Edition). Canadá: CIDECT(2011) Projetos De Estruturas De Aço E De Estruturas Mistas De Aço E Concreto De Edificações Com Perfis Tubulares, , PN 02:125.03-004, Rio de Janeiro: ABNTWardenier, J., Packer, J.A., Zhao, X.-L., Van Der Vegte, G.J., (2010) Hollow Sections In Structural Applications, p. 232. , Netherland: Bouwen met Staa

Chromone derivatives and other constituents from cultures of the marine sponge-associated fungus penicillium erubescens KUFA0220 and their antibacterial activity

A previously unreported chromene derivative, 1-hydroxy-12-methoxycitromycin (1c), and four previously undescribed chromone derivatives, including pyanochromone (3b), spirofuranochromone (4), 7-hydroxy-6-methoxy-4-oxo-3-[(1E)-3-oxobut-1-en-1-yl]-4H-chromene-5-carboxylic acid (5), a pyranochromone dimer (6) were isolated, together with thirteen known compounds: β-sitostenone, ergosterol 5,8-endoperoxide, citromycin (1a), 12-methoxycitromycin (1b), myxotrichin D (1d), 12-methoxycitromycetin (1e), anhydrofulvic acid (2a), myxotrichin C (2b), penialidin D (2c), penialidin F (3a), SPF-3059-30 (7), GKK1032B (8) and secalonic acid A (9), from cultures of the marine sponge- associated fungus Penicillium erubescens KUFA0220. Compounds 1a-e, 2a, 3a, 4, 7-9, were tested for their antibacterial activity against Gram-positive and Gram-negative reference and multidrug-resistant strains isolated from the environment. Only 8 exhibited an in vitro growth inhibition of all Gram-positive bacteria whereas 9 showed growth inhibition of methicillin-resistant Staphyllococus aureus (MRSA). None of the compounds were active against Gram-negative bacteria tested. © 2018 MDPI. All Rights Reserved.Funding: This research was funded by Fundação para a Ciências e Tecnologia (FCT) (grant number POCI-01-0145-FEDER-016790) and North Portugal Regional Operational Programme (NORTE 2020)(grant number NORTE-01-0145-FEDER-000035). Acknowledgments: This work was partially supported through national funds provided by FCT/MCTES-Foundation for Science and Technology from the Minister of Science, Technology and Higher Education (PIDDAC) and European Regional Development Fund (ERDF) through the COMPETE—Programa Operacional Factores de Competitividade (POFC) programme, under the project PTDC/MAR-BIO/4694/2014 (reference POCI-01-0145-FEDER-016790; Project 3599-Promover a Produção Científica e Desenvolvimento Tecnológico e a Constituição de Redes Temáticas (3599-PPCDT)) in the framework of the programme PT2020 as well as by the project INNOVMAR-Innovation and Sustainability in the Management and Exploitation of Marine Resources (reference NORTE-01-0145-FEDER-000035, within Research Line NOVELMAR), supported by North Portugal Regional Operational Programme (NORTE 2020), under the PORTUGAL 2020 Partnership Agreement, through the European Regional Development Fund (ERDF). Decha Kumla thanks the Alfabet Project of the Erasmus Mundus for a PhD’s scholarship. We thank Júlia Bessa and Sara Cravo for technical support

Development and bloom in hybrids of wild passion fruit cultivated in different types of pots and shading levels

Ornamental hybrids of passion flowers are thoroughly diffused in many countries and used in the decoration of houses and gardens. However, the cultivation of ornamental passion fruits practically unexploited in Brazil. This study aimed at evaluating the growth and blooming of F1 hybrids of Passiflora L. (P. sublanceolata J.M. MacDougal [ex P. palmeri var. sublanceolata Killip] vs. P. foetida var. foetida L.) cultivated in ceramic and concrete pots under different shading levels. The vegetative and flower evaluations were carried out weekly, in clonal cuttings 60 days after rooting. The height, leaf length and width, the number of internodes and leaves and stem diameter were evaluated using a randomized complete design in a factorial scheme which corresponded to two genotypes, two types of pot, three shading levels (25 %, 50 %, 75 %) and seven weeks of evaluation, with four replications. For the variable number of flowers, the same experimental design was adopted. However, the number of evaluations was modified for three periods, but this was not considered for the flower diameter and leaf area. The shading levels of 25 % and 50 % were the most favorable to the growth in height, whereas hybrid genotypes under 25 % shade had greater increase in the number of leaves, internodes and stem diameter, showing tolerance to moderate shade. The higher values for length, width and leaf area were observed at 75 % shade. The greatest number of flowers was verified at 25 % shadow in concrete pots. As for the types of pot, the ceramic ones were more favorable to the growth of hybrid plants during the first weeks of acclimatization to the treatments, and the concrete ones were more propitious to blooming. Thus, the use of hybrid plants in concrete pots for the ornamentation of internal environments is recommended, if they are well illuminated

Oxidation mechanisms occurring in wines

The present review aims to show the state of the art on the oxidation mechanisms occurring in wines, as well as the methods to monitor, classify and diagnose wine oxidation. Wine oxidation can be divided in enzymatic oxidation and non-enzymatic oxidation. Enzymatic oxidation almost entirely occurs in grape must and is largely correlated with the content of hydroxycinnamates, such as caffeoyltartaric acid and para-coumaroyltartaric acid, and flavan-3-ols. Non-enzymatic oxidation, also called chemical oxidation of wine, prevails in fermented wine and begin by the oxidation of polyphenols containing a catechol or a galloyl group. These phenolic reactions, both enzymatic and non-enzymatic, result in by-products named quinones. However, in non-enzymatic oxidation, oxygen does not react directly with phenolic compounds. The limitation on the reactivity of triplet oxygen is overcome by the stepwise addition of a single electron, which can be provided by reduced transition metal ions, essentially iron(II) and copper(I). The sequential electron transfer leads to the formation of hydroperoxide radical (HOO•), hydrogen peroxide (H2O2), and hydroxyl radical (HO•). The later radical will oxidize almost any organic molecule found in wine and will react with the first species it encounters, depending on their concentration. Sulfur dioxide (SO2) and ascorbic acid, when added to wine, are able to reduce the quinones. Alternative options have been assessed for the prevention of oxidation during wine storage; nevertheless, these are not fully understood or commonly accepted. During aging, aldehydes are important intermediates in the chemical transformations occurring in wines, leading to color and flavor changes. In the same way, a range of off-flavors can be formed from wine oxidation. At low concentrations these flavors may add to the complexity of a wine, but as these increase they begin to detract from wine quality. In addition to the major chemical browning involving wine phenols, the main oxidation reactions occurring during grape juice heating or storage are caramelization and Maillard reaction, which are temperature dependent. Different methods have been proposed in the literature, addressing the complexity and multi-scale related with the oxidation process, to attempt the quantification of antioxidant activity in wines. These methods can be broadly divided in: i) methods based on chemical reactions and ii) methods based on the chemical-physical properties of antioxidants. © 2011 Elsevier Ltd.Revie

A new ergosterol analog, a new bis-anthraquinone and anti-obesity activity of anthraquinones from the marine sponge-associated fungus Talaromyces stipitatus KUFA 0207

A new ergosterol analog, talarosterone (1) and a new bis-anthraquinone derivative (3) were isolated, together with ten known compounds including palmitic acid, ergosta-4,6,8(14),22- tetraen-3-one, ergosterol-5,8-endoperoxide, cyathisterone (2), emodin (4a), questinol (4b), citreorosein (4c), fallacinol (4d), rheoemodin (4e) and secalonic acid A (5), from the ethyl acetate extract of the culture of the marine sponge-associated fungus Talaromyces stipitatus KUFA 0207. The structures of the new compounds were established based on extensive 1D and 2D spectral analysis, and in the case of talarosterone (1), the absolute configurations of its stereogenic carbons were determined by X-ray crystallographic analysis. The structure and stereochemistry of cyathisterone (2) was also confirmed by X-ray analysis. The anthraquinones 4a-e and secalonic acid A (5) were tested for their anti-obesity activity using the zebrafish Nile red assay. Only citreorosein (4c) and questinol (4b) exhibited significant anti-obesity activity, while emodin (4a) and secalonic acid A (5) caused toxicity (death) for all exposed zebrafish larvae after 24 h. © 2017 by the authors. Licensee MDPI.This work was partially supported through national funds provided by the FCT-Foundation for Science and Technology and European Regional Development Fund (ERDF) and COMPETE, under the projects PEst-C/MAR/LA0015/2013, PTDC/MAR-BIO/4694/2014, as well as by the project INNOVMAR - Innovation and Sustainability in the Management and Exploitation of Marine Resources (reference NORTE-01-0145-FEDER-000035, within Research Line NOVELMAR/INSEAFOOD /ECOSERVICES), supported by the North Portugal Regional Operational Programme (NORTE 2020), under the PORTUGAL 2020 Partnership Agreement, through the European Regional Development Fund (ERDF). J. Noitnart thanks the ALFABET project under the ERASMUS MUNDUS ACTION 2 with South East Asia, for a scholarship. We thank J?lia Bessa and Sara Cravo for technical support

Comparison among series compensators for transient stability enhancement of doubly fed induction generator based variable speed wind turbines

This study investigates the effects of series compensators, such as the dynamic voltage restorer (DVR), series dynamic braking resistor, thyristor switched series capacitor, and the high temperature superconducting fault current limiter (SFCL), in enhancing the transient stability of a doubly fed induction machine based variable speed wind generator system. The tested system consists of a 9 MW doubly fed induction generator based wind farm connected to an infinite bus through two step-up transformers and a double run transmission lines. A three-phase-to-ground (3LG) fault and a single-line-to-ground fault (1LG) were applied to one of the lines to demonstrate the transient stability enhancement ability of the series devices. A performance comparison among the four series compensators is made based on responses of active/reactive power, terminal voltage, rotor speed, dc link voltage, and current variations. Simulations were carried out in the MATLAB/Simulink environment. Simulation results show that all series devices can improve the transient stability, however, the SFCL is the most efficient in terms of active power, rotor speed stability and fault current suppression, and the DVR seems to have a better performance than the SFCL in terms of voltage and reactive power