Robustness of timber structures in seismic areas

Major similarities between robustness assessment and seismic design exist, and significant information can be brought from seismic design to robustness design. As will be discussed, although some methods and limitations considered in seismic design can improve robustness, the capacity of the structure to sustain limited damage without disproportionate effects is significantly more complex. In fact, seismic design can either improve or reduce the resistance of structures to unforeseeable events, depending on the structural type, triggering event, structural material, among others. Based on a case study, the influence of redundancy and ductility on the seismic behavior and robustness of a long-span timber structure is assessed.COST E 5

Solid catalysts obtained from wastes for FAME production using mixtures of refined palm oil and waste cooking oils

More than 95% of biodiesel production feedstocks come from edible oils, however it may cause some problems such as the competition of land use between food production and biodiesel production. The waste cooking oils (WCO) are an alternative feedstock for biodiesel production; its usage reduces significantly the cost of biodiesel production and has environmental benefits, e.g., a waste recovery instead of its elimination. This work aims to produce a low-cost efficient solid catalyst for fatty acid methyl esters (FAME) production using mixtures of refined palm oil (RPO) and WCO. Four low cost catalysts were prepared (biomass fly ashes, natural dolomite rock, chicken eggshells and polyethylene terephthalate - PET), characterized (by SEM, EDX, XRD, BET, FT-IR and Hammett indicators) and tested regarding their performance in FAME production. The maximum yield of FAME achieved was around 96%wt. for biomass fly ashes catalyst at 60 °C, 9:1 (mol/mol) of methanol to oil mixture, 10%wt. catalyst to oil mixture, over 180 min in batch reactor. The results point out for promising bifunctional catalysts able to achieve also conversion of free fatty acids up to 100% using mixtures of RPO and WCO.publishe

Assessing the effects of link-repair sequences on road network resilience

Disruptions to transport networks are inevitable and detrimental to the functioning of society. Improving the resilience of transport networks to disruptive events has, therefore, a significant impact on society. Although the resilience of a transport system depends on the ability of the network to sustain the consequences of initial disruption (i.e. robustness) and quickly recover its performance (i.e. rapidity), the latter attracted less attention than robustness. The present paper focuses on quantifying the impacts of recovery processes and, more specifically, link-repair strategies on resilience. Several link-repair strategies are compared across a multitude of perturbation scenarios in the well-known Sioux Falls network. The strategies considered include: (i) the optimal (minimising the disruption consequences over the recovery process), (ii) average (representing a recovery process where the disrupted links are repaired in random order), (iii) flow-based (where the links with the highest traffic flow in the undisrupted network are repaired first), and (iv) criticality-based (where the links whose individual failure result in the highest impacts on the system performance are repaired first) recovery. The results of this comparison are subsequently used to evaluate the correlation between robustness and resilience, and characterise the optimal repair strategy

Using a random road graph model to understand road networks robustness to link failures

Disruptions to the transport system have a greater impact on society and the economy now than ever before due to the increased interconnectivity and interdependency of the economic sectors. The ability of transport systems to maintain functionality despite various disturbances (i.e. robustness) is hence of tremendous importance and has been the focus of research seeking to support transport planning, design and management. These approaches and findings may nevertheless be only valid for the specific networks studied. The present study attempts to find universal insights into road networks robustness by exploring the correlation between different network attributes and network robustness to single, multiple, random and targeted link failures. For this purpose, the common properties of road graphs were identified through a literature review. On this basis, the GREREC model was developed to randomly generate a variety of abstract networks presenting the topological and operational characteristics of real-road networks, on which a robustness analysis was performed. This analysis quantifies the difference between the link criticality rankings when only single-link failures are considered as opposed to when multiple-link failures are considered and the difference between the impact of targeted and random attacks. The influence of the network attributes on the network robustness and on these two differences is shown and discussed. Finally, this analysis is also performed on a set of real road networks to validate the results obtained with the artificial networks

Co-existence Of Ants And Termites In Cecropia Pachystachya Trécul (urticaceae)

Individuals of Cecropia pachystachya Trécul (Urticaceae) host Azteca (Hymenoptera: Formicidae) colonies in their hollow internodes and feed them with glycogen bodies produced in modified petiole bases (trichilia). In turn, ants keep trees free from herbivores and lianas. Here, we report for the first time the association of nests of Nasutitermes ephratae Rambur (Isoptera: Termitidae) with these trees, in South-Pantanal (Brazil). We aimed to describe the Cecropia-ant-termite relationship and to investigate how their coexistence is made possible. We hypothesize that: 1) The frequency of termite nests in C. pachystachya is lower than in neighbor trees; 2) Termite nests occur in trees with lower density of foraging ants; 3) The time that ants take to find and remove live termite baits in C. pachystachya trees is lower in leaves (close to trichilia) than in trunks; 4) Termite nests are fixed preferentially in the smallest and less branched trees; and 5) Termite nests are fixed preferentially distant from the canopies. Unexpectedly, termitaria occurred in C. pachystachya at the same frequency as in other tree species; there was no relationship between ant patrol activity and the occurrence of termite nests in C. pachystachya; and they occurred mainly in the tallest and more branched trees. However, termite nests generally were fixed in the trunk, fork or basal branches, where there is better physical support and ant patrol is more modest. The segregation of termite and ant life-areas may represent a escape strategy of termites in relation to ants inhabiting C. pachystachya, specially during nest establishment. The isolation of termites in fibrous nests and galleries may complete their defense strategy.6118894Agrawal, A.A., Leaf damage and associated cues induce aggressive ant recruitment in a neotropical ant-plant (1998) Ecology, 79, pp. 2100-2112Agrawal, A.A., Dubin-Thaler, B.J., Induced Responses to Herbivory in the Neotropical Ant-Plant Association between Azteca Ants and Cecropia Trees: Response of Ants to Potential Inducing Cues (1999) Behavioral Ecology and Sociobiology, 45, pp. 47-54Alho, C.J.R., Gonçalves, H.C., (2005) Biodiversidade Do Pantanal: Ecologia e Conservação, p. 135. , Campo Grande: Editora UniderpBerg, C.C., Rosselli, P.F., Davidson, D.W., (2005) Flora Neotropica: Cecropia, 94, p. 236. , New York: New York Botanical Garden PressBraekman, J.C., Daloze, D., Dupont, A., Pasteels, J.M., Le-Feuve, P., Borderau, C., Declercq, J.P., Van Meerssche, M., Chemical composition of the frontal gland secretion from soldiers of Nasutitermes lujae (Termitidae: Nasutermi-tinae) (1983) Tetrahedron, 39, pp. 4237-4241Carroll, C.R., Janzen, D.H., Ecology of foraging by ants (1973) Annual Review of Ecology and Systematics, 4, pp. 231-257Cunha, H.F., (2000) Estudo de Colônias de Constrictotermes Cyphergaster (Isoptera, Termitidae: Nasutitermitinae) No Par-que Estadual da Serra de Caldas Novas, GO, p. 51. , Dissertação de mestrado, Univ. Federal de Goiás, Instituto de Ciências Bio-lógicas/DBG, GoiâniaDavidson, D.W., Fisher, B.L., Symbiosis of ants with Cecropia as a function of light regime (1991) Ant-Plant Interactions, pp. 289-309. , Huxley, C. & Cutler, D. K. (eds.), New York: Oxford University PressDavidson, D.W., McKey, D., The evolutionary ecology of symbiotic ant-plant relationships (1993) Journal of Hymenoptera Research, 2, pp. 13-83Dejean, A., Fénéron, R., Predatory behaviour in the ponerine ant, Centromyrmex bequaerti: A case of termitolesty (1999) Behavioural Processes, 47, pp. 125-133Dejean, A., Grangier, J., Leroy, C., Orivel, J., Preda-tion and aggressiveness in host plant protection: A generalization using ants of the genus Azteca (2009) Naturwissenschaften, 96, pp. 57-63Delabie, J.H.C., Inquilinismo simultâneo de duas es-pécies de Centromyrmex (Hymenoptera: Formicinae: Pone-rinae) em cupinzeiros de Syntermes sp. (Isoptera: Termitidae: Nasutiterminae) (1995) Revista Brasileira de Entomologia, 39, pp. 605-609Downhower, J.F., The distribution of ants on Cecropia leaves (1975) Biotropica, 7, pp. 59-62Eisner, T., Kriston, I., Aneshansley, D.J., Defensive Behavior of a Termite (Nasutitermes exitiosus) (1976) Behavioral Ecology and Sociobiology, 1, pp. 83-125Folgarait, P.J., Johnson, H.L., Davidson, D.W., Responses of Cecropia to experimental removal of mullerian bodies (1994) Functional Ecology, 8, pp. 22-28Gonçalves, T.T., Reis, R., Desouza, O., Ribeiro, S.P., Predation and interference competition between ants (Hymenoptera: Formicidae) and arboreal termites (Isoptera: Termitidae) (2005) Sociobiology, 46, pp. 409-419Higashi, S., Ito, F., Defense of termitaria by termito-philous ants (1989) Oecologia, 80, pp. 145-147Hölldobler, B., Wilson, E.O., (1990) The Ants, p. 732. , Berlin: Harvard University PressJanzen, D.H., Coevolution of mutualism between ants and acacias in Central America (1966) Evolution, 20, pp. 249-275Janzen, D.H., Allelopathy by myrmecophytes: The ant Azteca as an allelopathic agent of Cecropia (1969) Ecology, 50, pp. 147-153Janzen, D.H., Dissolution of mutualism between Cecropia and its Azteca ants (1973) Biotropica, 5, pp. 15-28Lemaire, M., Lange, C., Lefevre, J., Clement, J.L., Stra-tegie de camoufage du prédateur Hypoponera eduardi dans les sociétés de Reticulitermes européens (1986) Actes Coll. Insectes So-ciaux., 2, pp. 97-101Longino, J.T., Azteca ants in Cecropia trees: Taxonomy, colony structure and behaviour (1991) Ant-Plant Interactions, pp. 198-212. , Cutler, D. F. & C. R. Huxley (eds.), New York: Oxford University PressNoirot, C., Darlington, J.P.E.C., Termites nests: Architecture, regulation and defence (2000) Termites: Evolution, Sociality, Symbioses, Ecology, pp. 121-139. , Abe, T., et al. (eds.), Dordrecht: Kluwer Academic PublishersOliveira, P.S., Oliveira-Filho, A.T., Cintra, R., Ant foraging on ant-inhabited Triplaris (Polygonaceae) in western Brazil: A feld experiment using live termite-baits (1987) Journal of Tropical Ecology, 3, pp. 193-200Pott, A., Pott, V.J., Plantas do Pantanal (1994) Brasília: Embrapa-SPI, p. 320Putz, F.E., Holbrook, N.M., Further observations on the dissolution of mutualism between Cecropia and its ants: The Malaysian case (1988) Oikos, 53, pp. 121-125Quinet, Y., Tekule, N., Biseau, J.C., Behavioural interactions between Crematogasterbrevispinosa rochai Forel (Hymenoptera: Formicidae) and two Nasutitermes species (Isoptera: Termitidae) (2005) Journal of Insect Behavior, 18, pp. 1-17. , doi: 10.1007/s10905-005-9343-yRico-Gray, V., Oliveira, P.S., (2007) The Ecology and Evolution of Ant-plant Interactions, p. 320. , Chicago: University of Chicago PressRickson, F.R., Glycogen plastids in Müllerian body cells of Cecropia peltata-a higher green plant (1971) Science, 173 (3994), pp. 344-347. , doi: 10.1126/science.173.3994.344Sagers, C.L., Ginger, S.M., Evans, R.D., Carbon and nitrogen isotopes trace nutrient exchange in an ant-plant mutualism (2000) Oecologia, 123, pp. 582-586Sheppe, W., Invertebrate predation on termites of the African savanna (1970) Insectes Sociaux, 17, pp. 205-218Schupp, E.W., Azteca protection of Cecropia: Ant occupation benefts juvenile trees (1986) Oecologia, 70, pp. 319-385Soriano, B.M.A., Oliveira, H., Catto, J.B., Comastri-Filho, J.A., Galdino, S., Salis, S.M., (1997) Plano de Utilização da Fazenda Nhumirim (Documento 21), p. 72. , http://www.cpap.embrapa.br/publicacoes/online/DOC21.pdf, Corumbá: Embrapa-CPAP, (accessed date: 12 November, 2013)Thorne, B.L., Diferences in nest architecture between the neotropical arboreal termites Nasutitermes corniger and N. Ephrateae (Isoptera, termitideae) (1980) Psyche, 87, pp. 235-244Thorne, B.L., Haverty, M.I., Nest growth and survivorship in three species of neotropical Nasutitermes (Isoptera: Termitidae) (2000) Environmental Entomology, 29, pp. 256-264Vasconcelos, H.L., Casimiro, A.B., Infuence of Azteca alfari ants on the exploitation of Cecropia trees by a leaf-cutting ant (1997) Biotropica, 29, pp. 84-92Vasconcellos, A., Moura, F.M.S., Wood litter consumption by three species of Nasutitermes termites in an area of the Atlantic Coastal Forest in northeastern Brazil (2010) Journal of Insect Science, 10, p. 72. , http://insectscience.org/10.72/Vieira, A.S., Faccenda Antonialli-Junior O, W.F., Fernandes, W.D., Nest structure and occurrence of three species of Azteca (Hymenoptera, Formicidae) in Cecropia pachystachya (Urticaceae) in non-foodable and foodable pantanal areas (2010) Revista Brasileira de Entomologia, 54, pp. 441-445. , doi: 10.1590/S0085-56262013000100013Weber, N.A., Termite prey of some African ants (1964) Entomological News, 75, pp. 197-204Wheeler, W.M., Ecological relations of ponerinae and other ants to termites (1936) Proceedings of the American Academy of Arts and Science, 71, pp. 159-243Wheeler, W.M., Studies of neotropical ant-plants interactions ant their ants (1942) Bulletin of the Museum of Comparative Zoology Harvard, 90, pp. 1-262Wilson, E., (1971) The Insect Societies, p. 560. , Cambridge: Belknap Press of Harvard University Pres

Optimization of FAME production from blends of waste cooking oil and refined palm oil using biomass fly ash as a catalyst

One of the problems associated with biomass combustion is the amount of fly ashes generated and its subsequent management. The search for ways of valorizing these ashes has been a challenge for the academic and industrial community. On the other hand, used cooking oils are wastes which management is quite difficult, by they have a very important energetic potential. The goal of this work was to optimize the Fatty Acid Methyl Esters (FAME) process, recovering two residual materials (waste cooking oils (WCO), and biomass fly flash (BFA)). The optimization of the process was achieved using the response surface methodology and a Box-Benhken experimental design applied to mixtures of WCO and refined palm oil (RPO), using BFA as catalyst. The influence on FAME yield of four variables (catalyst loading, methanol/oil molar ratio, RPO/WCO ratio and reaction temperature) was studied. The higher FAME yield achieved was 73.8% for the following operating conditions: 13.57 wt% of catalyst loading, 6.7 of methanol/oil molar ratio, 28.04 wt% of RPO in the oil mixture with WCO and 55 °C for the reaction temperature. The reusability of the BFA catalyst in the process was also studied through three successive usage cycles finding no loss of catalytic activity.publishe

Smart coating for detection of early-stage corrosion of steel

ABSTRACT: The work describes the investigation of LDH-based nanoadditives for early-stage corrosion detection of steel, and subsequent development of a multi-layer functional protection coating. A systematic study on the level of degradation and the detected colorimetric signal was performed using electrochemical characterisation. The protection properties and detection functionality were also studied in conditions relevant to exploitation of metallic structures.info:eu-repo/semantics/publishedVersio

Implementation and calibration of finite-length plastic hinge elements for use in seismic structural collapse analysis

Finite-length plastic hinge (FLPH) models have shown advantages over the concentrated plasticity hinge (CPH) models. However, empirical phenomenological relationships, such as Modified Ibarra–Medina–Krawinkler (ModIMK) deterioration model, were mainly calibrated for use in CPH models. ModIMK relationships are versatile and have been applied to steel, reinforced concrete, and timber structures. Herein, a calibration procedure of FLPH models and a unified algorithm for use of ModIMK relationships in CPH and FLPH models are presented. Results from included examples validate the proposed algorithms, which were implemented in OpenSees. Additionally, results highlight that FPLH models avoid errors and convergence pitfalls of CPH models

Predicting olive phenology in Portugal in a warming climate

Prediction of flowering of olive trees should account for chilling requirements, using an appropriate chilling unit for the accounting of chilling accumulation. After chilling requirements are satisfied, dormancy break takes place. Thereafter, the trees enter the forcing phase, in which the thermal time approach is used, but an appropriate base temperature must be determined. Such a model was developed, calibrated and validated for many olive cultivars (De Melo-Abreu et al., 2004). After flowering, the occurrence of developmental stages may be predicted using a thermal time approach, but for warm regions a saw-tooth model, which is a model that reduces the effect of supra-optimal temperatures, is mandatory (Garcia-Huidobro et al., :1.982). According to the simulations of the model HadCM3, developed by the Hadley Centre, global climate warming will result in average temperature anomalies in winter, in Continental Portugal, of about 2°C, in SRES scenarios 81 and 82, 3°C in scenario A2, and 4 °C in scenario A:tFI, by the end of XXI century. (Miranda et al., 2006). In this study, we discuss the prediction of flowering and subsequent phenological stages and calculate and map the times of occurrence of flowering under three warming scenarios. No flowering or abnormal flowering events are also predicted.Portuguese Foundation for Science and Technology (FCT) under Project Futurolive (PTDC/AGR-AAM/:1.04562/2008)

Using a hazard-independent approach to understand road-network robustness to multiple disruption scenarios

A range of predictable and unpredictable events can cause road perturbations, disrupting traffic flows and more generally the functioning of society. To manage this threat, stakeholders need to understand the potential impact of a multitude of predictable and unpredictable events. The present paper adopts a hazard-independent approach to assess the robustness (ability to maintain functionality despite disturbances) of the Sioux Falls network to all possible disruptions. This approach allows understanding the impact of a wide range of disruptive events, including random, localised, and targeted link failures. The paper also investigates the predictability of the link combinations whose failure would lead to the highest impacts on the network performance, as well as, the correlation between the link-criticality rankings derived when only single-link failures are considered as opposed to when multiple-link failures are considered. Finally, the sensitivity of the robustness-assessment results to the intensity and distribution of the travel demand is evaluated