Artigos de Revista
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Mechanical characterization of clear wood from portuguese poplar
Poplar wood is a light, soft, and fast-growing timber from a hardwood species, characteristics that make it suitable for several applications. This study focused on the mechanical characterization of Portuguese poplar species, namely white poplar (Populus Alba) and black poplar (P. nigra), aiming for its structural use. Therefore, a sample of lamellae was assessed to determine its density and dynamic modulus of elasticity, using a non-destructive device, based on longitudinal vibrations. Clear wood specimens were obtained from a set of lamellae to perform tension and compression parallel-to-grain tests. These tests were used to determine the moduli of elasticity in tension and compression and the tensile and compressive strengths and strains. Also, typical stress-strain curves were identified for the sample studied. The results stressed the potential for structural applications of Portuguese poplar.
Ano: 2019
Número Páginas:
9.
Autor(es): Monteiro, S.; Martins, C.; Dias, A.; Cruz, H.
Revista: BioResources
Editor: North Carolina State University
Volume:
Vol. 14, nº 4.
Keywords: Ductile behavior; Tension and compression tests parallel-to-grain; Portuguese poplar; Clear wood; Mechanical characterization
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A Bridge Too Far? An Integrative Framework Linking Classical Protist Taxonomy and Metabarcoding in Lower Termites
N/A
Ano: 2018
Autor(es): Duarte, S.; Nobre, T.; Borges, P.; Lina Nunes
Revista: Frontiers in Microbiology
Editor: Frontiers Editorial Office
Volume:
9:2620..
Keywords: Taxonomy; Metabarcoding; Symbionts; Subterranean termites
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Properties of multilayered sandwich panels with an agglomerated cork core for interior applications in buildings
Four types of sandwich panels with multilayered designs were produced using wood veneer of Aleppo pine as face and inner sheets, and cork agglomerate as core,intended for use in construction as panelling or partition walls in interior applications. These multilayered sandwich panels were characterized regarding static hardnessand dimensional stability when facing changes in relative humidity and when subjected to a deformation. The panels showed a considerable increase in dimensional stability and shear strength with the increase of the number oflayers. The results suggest that the correct design choice, for example number of inner wood sheets and thickness of cork core layers, allows these sandwich panels to be used as non-structural construction elements such as partition walls.
Ano: 2018
Número Páginas:
143-153pp..
Autor(es): Lakreb, N.; Knapic, S.; Saporiti Machado, J.; Bezzazi, B.; Pereira, H.
Revista: European Journal of Wood Products
Editor: Springer
Volume:
76.
Keywords: Strenght; Dimensional stability; Sandwich panels; Cork
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Symbiotic flagellate protists as cryptic drivers of adaptation and invasiveness of the subterranean termite Reticulitermes grassei Clément
Changes in flagellate protist communities of subterranean termite Reticulitermes gras-sei across different locations were evaluated following four predictions: (i) Rural endemic (Portugal mainland) termite populations will exhibit high diversity of symbionts; (ii) invasive urban populations (Horta city, Faial island, Azores), on the contrary, will exhibit lower diversity of symbionts, showing high similarity of symbiont assemblages through environmental filtering; (iii) recent historical colonization of isolated regions
Ano: 2018
Número Páginas:
5242-5253pp.
Autor(es): Duarte, S.; Nobre, T.; Borges, P.; Lina Nunes
Revista: Ecology and Evolution
Editor: Wiley Online Library
Volume:
8 (11).
Keywords: Adaptation; Invasive species; Urban environment; Rural environment; Symbiotic flagellate protists; Subterranean termites
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Using non-destructive testing to predict the strength of poplar glued laminated timber
This paper describes the use of non-destructive methods to assess the mechanical properties of structural glued laminated timber made from poplar. The longitudinal vibration method and transformed section method were considered. Full-scale tests were also performed to determine the most relevant mechanical properties of 18 beams, namely modulus of elasticity and bending strength. In addition, the bonding performance of each beam was checked by delamination and shear strength tests. Detailed analysis of the results was performed and combined with Levene's and Tukey's tests. The accuracy of the two non-destructive test methods was evaluated by linear regression analysis. The transformed section method showed stronger correlations with modulus of elasticity and shear strength. Slightly lower values were presented by the longitudinal vibration method. A strength class of GL24c can be assigned for glued laminated poplar made with timber with lower properties at the inner lamellas.
Ano: 2018
Número Páginas:
16p.
Autor(es): Martins, C.; Dias, A.; Cruz, H.
Revista: Proceedings of the Institution of Civil Engineers - Structures and Buildings
Editor: Institution of Civil Engineers
Volume:
Volume 171 No. 8.
Keywords: Poplar; Non-destructive methodologies; Glued laminated timber; Natural resources; Statistical analysis; Strength & testing of materials; Timber structures
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Densification and heat treatment of maritime pine wood
Pine (Pinus pinaster Ait.) wood samples were subjected to a combined treatment by densification and heat treatment. Samples were densified before and after heat treatment. The heat treatment was made inside an oven at 190ºC during 2 to 6 h and wood densification was made in a hot press at around 48 bar pressure and temperatures between 160ºC and 200ºC for 30 min. Compression-set, compression-set recovery after three cycles of water soaking followed by oven drying, density, hardness, bending strength and stiffness and durability against subterranean termites were determined after the treatment. Results show that densification increases density, hardness, bending strength, stiffness and durability against termites. Heat treatment applied after the densification is more effective in reducing compression-set recovery than if applied before.
Ano: 2017
Autor(es): Esteves, B.; Ribeiro, F.; Lopes, L.; Ferreira, J.; Domingos, I.; Duarte, M.; Duarte, S.; Lina Nunes
Revista: Wood Research
Editor: Slovak Forest Products Research Institute
Volume:
62 (3): 373-388.
Keywords: Termite resistance; Compression set-recovery; Pinus pinaster; Heat treatment; Densification
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Dietary-driven variation effects on the symbiotic flagellate protist communities of the subterranean termite Reticulitermes grassei Clément
The ability of subterranean termites to digest lignocellulose relies not onlyon their digestive tract physiology, but also on the symbiotic relationshipsestablished with flagellate protists and bacteria. The objective of this workwas to test the possible effect of different cellulose-based diets on the communitystructure (species richness and other diversity metrics) of the flagellateprotists of the subterranean termite Reticulitermes grassei. Termitesbelonging to the same colony were subjected to six different diets (naturaldiet, maritime pine wood, European beech, thermally modified Europeanbeech, cellulose powder and starvation), and their flagellate protist communitywas evaluated after the trials.All non-treated sound woods produced similar flagellate protist communitiesthat were more diverse and of high evenness (low dominance).On the contrary, flagellate protist communities from cellulose-fed termitesand starving termites were considered to be significantly different from allnon-treated woods; they were less diverse and some morphotypes becamedominant as a consequence of flagellate protist communities having sufferedmajor adaptations to these diets. The flagellate protist communitiesof untreated beech and thermally modified beech-fed termites were consideredto be significantly different in terms of abundance and morphotypediversity. This may be caused by a decrease in lignocellulose qualityavailable for termites and from an interference of thermally treated woodwith the chemical stability of the termite hindgut.Our study suggests that as a consequence of the strong division oflabour among these protists to accomplish the intricate process of lignocellulosedigestion, termite symbiotic flagellate protist communities are adynamic assemblage able to adapt to different conditions and diets. Thisstudy is important for the community-level alteration approach, and it isthe first study to investigate the effects of thermally modified wood on theflagellate protist communities of subterranean termites.
Ano: 2017
Número Páginas:
300-307pp.
Autor(es): Duarte, S.; Duarte, M.; Borges, P.; Lina Nunes
Revista: Journal of Applied Entomology
Editor: Wiley Online Library
Volume:
141 (4).
Keywords: Digestion; Thermally modified wood; Symbiotic flagellate protists; Subterranean termites
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Evaluation of cross-sectional variation of timber bending modulus of elasticity by stress waves
Serviceability limit states (related to deformation) rather than ultimate limit states (related to collapse)are often the reason for the need to assess existing timber structures. Prediction of timber members
Ano: 2017
Número Páginas:
617-625pp..
Autor(es): Conde , M.; Saporiti Machado, J.
Revista: Construction and Building Materials
Editor: Elsevier
Volume:
134.
Keywords: Modulus of elasticity; Wood core; Stress waves; Timber variability
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Evaluation of glue line shear strength of laminated timber structures using block and core type specimens
Monitoring and evaluation of glued laminated timber structures in service is essential to warrant its integrity, where non-destructive techniques play an important role. This paper describes the results obtained on glued laminated timber beams of maritime pine, with and without preservative treatment, and of spruce, exposed to naturaloutdoor environment as well as to artificial weathering. The assessment of glue lines
Ano: 2017
Número Páginas:
13p.
Autor(es): Gaspar, F.; Cruz, H.; Gomes, A.
Revista: European Journal of Wood and Wood Products
Editor: Springer-Verlag GmbH Germany 2017
Keywords: Laminated timber structures
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Grading of portuguese maritime pine small-diameter roundwood
This paper presents work carried out with the aim of characterizing the mechanical behavior and developing visual and machine strength grading systems for Portuguese maritime pine roundwood for structural applications. Two samples of forty maritime pine logs each were collected, one in a northern region of Portugal and another in an interior central region. After drying, the logs were visually graded andsubjected to nondestructive tests, using vibration and ultrasounds, for determination of dynamic modulus of elasticity. The logs were then subjected to destructive tests for determining bending and compression strength and bending modulus of elasticity. These results were analyzed in order to identify the features to be considered in the strength grading process. From this analysis, a proposal was developed tovisually grade Portuguese maritime pine roundwood in two strength grades. According to the European strength class standard for solid timber, the upper grade has similar mechanical properties to the C50 class, whereas the lower grade is similar to the C35. The machine grading showed good potential as a result of the good correlation presented between the dynamic modulus of elasticity and the mechanical properties. However, the ultrasounds showed slightly better correlation than the vibration method, whereas the last one is more practical.
Ano: 2017
Autor(es): Morgado, T.; Dias, A.; Saporiti Machado, J.; Negrão, J.; Marques, A.
Revista: Journal of Materials in Civil Engineering
Editor: American Society of Civil Engineers
Volume:
vol. 29 ; n.2.
Keywords: Mechanical properties; Grading; Maritime pine
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Comunicações
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Electro osmotic pulsing technology (PLEOT)
Wood protection and control of infestation in buildings and other wooden cultural heritage objects is mainly based on chemical-, gas- and heat treatments. Degradation of wood is not only caused by fungi or bacteria but also by insects. Termites have been a potential risk to wooden structures not only in the warmer regions of our continents but also beyond the regions of their natural habitat due to transport of wood.A new environmental friendly wood protection system has been tested on wood destroying fungi and termites.Wood protection by means of electro osmotic pulsing technology (PLEOT) can preserve wood in service without using any chemical protection at all. The system can easily be installed and is very low in maintenance costs.The results show no mass loss of PLEOT protected beech and Scots pine sapwood samples exposed to the whiterot Trametes versicolor for 4 and 8 weeks. Termite attack could slightly be reduced by using this technology onScots pine sapwood samples.
Ano: 2010
Número Páginas:
5.
Autor(es): Treu, A.; Lina Nunes; Duarte, S.; Larnoy, E.
Keywords: Térmitas subterrâneas; Fungos destruidores de madeira; Electro osmotic pulsing technology; Subterranean termites; Wood destroying fungi
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Estrategias no uso do encamisamento localizado com chapas de aço que previlegiem a ductilidade ou o aumento diferenciado da resistência
O reforço selectivo materializado através de encamisamento localizado com chapas de aço, em pilares de betão armado de secção rectangular, pode induzir o aumento de ductilidade ou promover o aumento da resistência e da ductilidade.Aborda-se nesta comunicação alguns dos factores que podem influenciar o aumento da resistência do encamisamento localizado com chapas de aço, permitindo ao projectista direccionar a intervenção apenas para o aumento de ductilidade, para o aumento de ductilidade e um aumento de resistência moderado (+20%), para o aumento da ductilidade e aumento significativo da resistência (+80%) e ainda a possibilidade de utilizar a ligação do encamisamento à base/nó como
Ano: 2010
Número Páginas:
263-265.
Autor(es): Cardoso, A.
Editor: GPBE, LNEC
Keywords: Ductilidade; Reforço anti-sismico; Encamisamento localizado
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Influência na aderência aço-betão da alteração local da configuração geométrica das nervuras de armaduras de aço
N/A
Ano: 2010
Número Páginas:
12p.
Autor(es): André, J.; Pipa, M.
Editor: Grupo Português de Betão Estrutural
Keywords: Ensaios pull-out; Configuração geométrica; Armaduras de aço; Aderência aço-betão
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Laboratory study of fipronil baits against Reticulitermes grassei (Isoptera: Rhinotermitidae)
Fipronil is currently used as chemical barrier against subterranean termites, in this paper their possible use as bait has been tested. Their efficacy with Reticulitermes grassei Clément in feed forced and feed choice tests has been analyzed, evaluating the mortality caused by administration of fipronil at 1 and 10 ppm (wt/wt). Our results show that 90% mortality is achieved at 6 days with feed forced test at 10 ppm and 16 days at 1 ppm; but with choice test the time to achieve that level of mortality is increased to 17 days for 10 ppm and only 50% mortality in 28 day is obtained with 1 ppm. Moreover the filter paper consumed by termite/day has been evaluated, founding a diminution of ingestion with the increase of concentration. This suggests a possible unpalatability of product at all tested concentrations. Fipronil is currently used as chemical barrier against subterranean termites, in this paper their possible use as bait has been tested. Their efficacy with Reticulitermes grassei Clément in feed forced and feed choice tests has been analyzed, evaluating the mortality caused by administration of fipronil at 1 and 10 ppm (wt/wt). Our results show that 90% mortality is achieved at 6 days with feed forced test at 10 ppm and 16 days at 1 ppm; but with choice test the time to achieve that level of mortality is increased to 17 days for 10 ppm and only 50% mortality in 28 day is obtained with 1 ppm. Moreover the filter paper consumed by termite/day has been evaluated, founding a diminution of ingestion with the increase of concentration. This suggests a possible unpalatability of product at all tested concentrations.
Ano: 2010
Número Páginas:
10p.
Autor(es): Gaju, M.; Moyano, L.; Patiño, C.; Diz, J.; Lina Nunes; Bach de Roca, C.; Molero, R.
Keywords: Reticulitermes grassei; Termites; Baits; Fipronil
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Monotonic tests of structural carpentry joints
An experimental campaign on traditional diagonal front notched timber joints was carried out in order toassess their rotational behaviour. This campaign included ten different test conditions, comprising some of the mostfrequently observed configurations of the rafter and tie beam joint in Portuguese roof structures. The joints' mechanicalbehaviour was appraised with regard to their geometric parameters, presence of metal fastening devices and moisturecontent of timber. The experimental results show that the joint's response is different when opening or closing the skewangle and that specific load bearing mechanisms dictate the different performances exhibited by each typology.
Ano: 2010
Número Páginas:
6p.
Autor(es): Palma, P.; Gomes Ferreira, J.; Cruz, H.
Keywords: Mechanical behaviour; Tests; Carpentry joints; Connections; Timber structures
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On the use of wood protection by means of electro osmotic pulsing technology against subterranean termites
Wood protection in the last century has been mainly based on chemical treatments. Additionally, the type of construction of wooden buildings and the choice of wood species plays an important role.Degradation of wood is not only caused by fungi or bacteria but also by insects. Termites have been a poten¬tial risk to wooden structures not only in the warmer regions of our continents but also beyond the regions of their natural habitat due to transport of wood.A new environmental friendly wood protection system has been tested. Wood protection by means of electro osmotic pulsing technology can preserve wood in service without using any chemical protection at all. The system can easily be installed and is extremely low in maintenance costs.The technology [EOP] has been preliminary tested on Scots pine sapwood [Pinus sylvestris] against subter¬ranean termites [Reticulitermes grasseiJ in the laboratory. Two choice and non-choice tests were carried out using different initial wood moisture content, 4 weeks of exposure and 6 replicates per variable.The results show heavy growth of mould fungi on wood samples with higher moisture content that probably contribute to higher termite mortality on wetter samples. EOP treatment strongly reduced the development of moulds and gave variable results in terms of termite survival and feeding.Further testing is needed to better understand the possibilities of this method to subterranean termite control.
Ano: 2010
Número Páginas:
1.
Autor(es): Treu, A.; Lina Nunes; Larnoy, E.
Editor: Universidade Fernando Pessoa
Keywords: Subterranean termites; Electro osmotic pulsing technology
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Performance of Paraloid B72® combined with the application of biocides on wood degraded by fungi
When timber elements in heritage buildings are moderately degraded by fungi and assuming underlying moisture problems are solved, two actions can be taken: i) use a biocide product to stop fungi activity ii) consolidate the degraded elements so that the timber keeps on fulfilling its structural and decorative functions. Indeed, the option of maintaining in the building the original (even though deteriorated) timber has been gaining more and moreimportance, as the loss any element may contribute to the loss of the historical identity of the building.This paper presents the laboratory work performed with the purpose of understanding the mechanical performance of maritime pine timber degraded by fungi (with mass losses lower than 20%) when subjected to consolidation by impregnation with Paraloid B72®, combined with the previous application of a biocide.Three commercially available pre-selected biocide products were used: a light organic solvent (X), a boron water-based (BC) and a water-based emulsion (A). After the products were applied to five sets of specimens (Control, PB72, X+PB72, BC+PB72, A+PB72) these were subjected to mechanical tests: axial compression test (NP618) and resistance to indentation (ISO 3350). Four similar sets of replicates were subjected to an evaporation ageing procedure (EN73) after the products were applied and equally tested.An increase in mechanical strength was observed for the consolidation product with no significant influence of the previous use of biocide product. The specimens subjected to ageing showed a slightly better general mechanical performance than those not aged.
Ano: 2010
Número Páginas:
8.
Autor(es): Henriques, J. D.; Lina Nunes; Brito, J.
Keywords: Biocidas; Madeira degradada por fungos; Biocides; Wood degraded by fungi; Paraloid b72®
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Predicting the mechanical behaviour of solid pine timber elements thyough non and semi-destructive methods
Timber elements can be foreseen as lengthwise composites of clear and knot zones, being the clear wood zones greatly responsible for stiffness and the weakest zones (worst knots shown by the timber element) for the ultimate strength capacity. In the present study non destructive techniques (ultrasounds and visual grading) and semi-destructive techniques (tension meso-specimens and core drilling) are used and tested as tools for evaluating clear wood properties. These properties are then used to predict the global modulus of elasticity of maritime pine timber beams. The results obtained delivered important information concerning variability within and between timber pieces. The non and semidestructive techniques used have shown a reasonable capability to predict the clear wood properties and to deliver a good prediction of the global bending modulus of elasticity.
Ano: 2010
Número Páginas:
6p.
Autor(es): Saporiti Machado, J.; Palma, P.
Keywords: Tension testing; Meso-specimens; Core drilling; Ultrasounds; Visual grading
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Preventing decay in termite monitoring stations
In-ground monitoring stations and termite baits are widely used in the southern United States with the intent of detecting and eradicating subterranean termite activity near buildings. These stations comprise a wood (or other cellulose material) substrate (monitor) and perhaps a termiticidal toxicant (bait) held m a plastic cage that allows for both, easy examination and access by termites. The usual practice is to inspect the station monitors for termite aetiv1ty every few months. If termites are detected, a bait is added to ar replaces the untreated monitor. However, in addition to termite attack, the monitors are subject to fungal decay, and rapid decay in high hazard areas is interfering with the usefulness of this baiting approach.This paper reports on an evaluation of the relative decay susceptibility of termite baiting systems used in commercial monitoring stations. Some monitors are very susceptible to wetting and fungal decay. corroborating anecdotal evidence from the field. It was eonc1uded that decay in high hazard areas is likely to interfere with the usefulness of some of these systems. To be used successfully, possible approaches to overcome the decay issue are: careful selection of the system used; placement on or above ground rather than in the ground; recognition that monitors and/or baits need to be changed every few months; avoiding remote sensing systems that do not allow a visual check of the monitor; developing durable m0nitors and baits, e.g., with the addition of a non-termite-repellent fungicide.
Ano: 2010
Número Páginas:
12p.
Autor(es): Taylor, A.; Kim, J.; Duarte, S.; Lina Nunes; Lloyd, J.
Keywords: Termiticide; Subterranean termites; Monitor stations; Fungicide; Decay; Baits
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Reabilitação de ligações em estruturas antigas de madeira - avaliação experimental
Apresentam-se os resultados de uma campanha experimental realizada no LNEC com oobjectivo de avaliar a viabilidade técnica de algumas soluções de reparação e reforço deligações tradicionais em estruturas de madeira, por meio entalhes, com e sem ferragens. Os resultados obtidos permitem avaliar o desempenho destas intervenções relativamente ao comportamento das ligações originais.
Ano: 2010
Número Páginas:
11p.
Autor(es): Palma, P.; Garcia, H.; Appleton, J.; Cruz, H.
Keywords: Reforço; Reparação; Ensaios; Ligações; Estruturas de madeira
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Livros
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Térmita-de-madeira-seca. West Indian drywood termite
N/A
Ano: 2019
Número Páginas:
144-145pp.
Autor(es): Duarte, S.; Lina Nunes
Revista: Guia Prático da Fauna Terrestre dos Açores
Editor: Instituto Acoriano da Cultura
Keywords: Cryptotermes brevis
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Térmita-de-pescoço-amarelo. Yellow-necked drywood termite; European drywood termite
N/A
Ano: 2019
Número Páginas:
146-147pp.
Autor(es): Duarte, S.; Lina Nunes
Revista: Guia Prático da Fauna Terrestre dos Açores
Editor: Instituto Açoriano da Cultura
Keywords: Kalotermes flavicollis
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Térmita-subterrânea-americana. Easten subterranean termite
N/A
Ano: 2019
Número Páginas:
148-149pp.
Autor(es): Duarte, S.; Lina Nunes
Revista: Guia Prático da Fauna Terrestre dos Açores
Editor: Instituto Açoriano da Cultura
Keywords: Reticulitermes flavipes
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Térmita-subterrânea-ibérica. Iberian subterrarean termite
N/A
Ano: 2019
Número Páginas:
150-151pp.
Autor(es): Duarte, S.; Lina Nunes
Revista: Guia Prático da Fauna Terrestre dos Açores
Editor: Instituto Açoriano da Cultura
Keywords: Reticulitermes grassei
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Estudo histórico e científico da Xiloteca da Academia das Ciências de Lisboa construída por José Aniceto Rapozo - nota preliminar
O Museu da Academia das Ciências de Lisboa possui uma preciosa xiloteca assinada pelo Mestre dos marceneiros portugueses, José Aniceto Rapozo contendo 1213 amostras de madeiras do Brasil e 12 de outras origens. A sua importância no progresso do conhecimento dos recursos florestais do Brasil naviragem dos séculos dezoito e dezanove conduziu ao estudo em curso. Dada a devastação verificada em vastas áreas florestais brasileiras, surgem dificuldades por certas espécies poderem ter distribuiçãogeográfica diferente (com eventual extinção, geral ou localizada), por insuficiência do material de comparação, e por ambiguidade das designações comerciais.Foi possível identificar esta xiloteca como uma de quatro encomendadas a Aniceto Rapozo pelo Príncipe Regente. A análise das amostras de madeira e a informação documental mostram que a colecçãotem por base uma remessa de 5008 amostras de madeiras do Brasil enviada em 1784 para o Arsenal Real do Exército, em Lisboa, pelo Vice-Rei do Brasil, Luís de Vasconcellos e Souza.O valor científico do conjunto é evidenciado pela identificação botânica das espéciesrepresentadas. Na situação actual, a identificação das espécies florestais representadas na amostragem foiinteiramente conseguida em 14% dos casos, conseguida mas ainda por confirmar em 27%. Dado o carácter preliminar deste estudo, os seus resultados serão ulteriormente publicados com mais pormenor. Among the Lisbon Academy of Sciences Museum collection there is a valuable xylarium by theleading Portuguese master cabinet-maker José Aniceto Rapozo (1756-1824), comprising 1213 wood samples from Brazil plus 12 from elsewhere. This collection is most important since it allows us to improve the knowledge on Brazilian forest resources by the end of the eighteenth century and thebeginning of the next. This study aims to establish its historical framework and scientific value. Owing tooverexploitation and even devastation of very large forest areas in Brazil, difficulties for our study aroseeither as some species may have now a different geographical distribution (and eventually may have underwent local or general extinction), by lack of adequate comparison material, or because of ambiguityof the commercial names.Results so far obtained allowed us to recognize the xylarium as one of the four commanded Rapozo by the Regent Prince, later King João VI (1767-1826). Taking into account the wood samples analyses as well as bibliographic data it is possible to conclude that the collection was prepared from a set 3 of 5008 Brazilian wood samples sent to the Royal Arsenal in Lisbon in 1784 by the Brazil
Ano: 2013
Número Páginas:
9.
Autor(es): Saporiti Machado, J.; Antunes, M.
Editor: Academia das Ciências de Lisboa (ACL)
Keywords: Identification; History; Brazil; Woods; Xylarium; Lisbon academy of sciences; Identificação; História; Brasil; Madeiras; Xiloteca; Academia das ciências de lisboa
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Capítulos de Livros
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A Review of Laboratory Tests to Evaluate Agro-Industrial Wastes Properties as Building Materials
This work collects information about laboratory tests to evaluate the properties of agro-industrial wastes used for thermal insulation building materials considering them individually and in composits. It focuses on bio-susceptibility, as one of the main aspects to consider for bio-based building products.
Ano: 2023
Número Páginas:
2p..
Autor(es): Cintura, E.; Lina Nunes; Faria, P.
Revista: Testing and Experimentation in Civil Engineering
Editor: Springer Nature
Volume:
Volume 41.
Keywords: Test methods; Bio-wastes; Bio-susceptibility; Bio-based materials
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Innovative Durability Tests on Construction Materials
Innovation in structures and construction materials demands a more accurate performance analysis during the life cycle. In addition, climatic changes pose new challenges to civil infrastructures that were not so relevant in the past. In most cases, the traditional test methods cannot accurately assess the complex phenomena involved in durability. The modern and complex factors require a different approach to durability analysis. The purpose of this chapter is to present innovative durability tests on construction materials: wood; rammed earth, cob and unfired blocks; natural stone; bituminous binders and mixtures; and Fibre Reinforced Polymers (FRP) to concrete bonded connections. Most of these tests concern the accelerated simulation of the main phenomena involved in durability performance
Ano: 2023
Número Páginas:
53-73pp..
Autor(es): Chastre, C.; Faria, P.; Neves, J.; Ludovico-Marques, M.; Biscaia, H.; Lina Nunes
Revista: Advances on Testing and Experimentation in Civil Engineering
Editor: Springer
Keywords: Performance; Innovation; Durability; ccelerated durability tests; Accelerated durability tests; Ageing techniques
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Optimisation of Production Parameters to Develop Innovative Eco-efficient Boards
Laboratory tests were carried out to define production parameters of innovative eco-efficient composites made up of hazelnut shells as aggregate and a sodium silicate solution as adhesive. The aim was to maximize the content of bio-aggregates and minimize the amount of adhesive, guaranteeing the feasibility of producing samples. Therefore, after preliminary testing, the percentages of hazelnut shells and the sodium silicate solution were kept constant: 70% and 30% of the total volume, respectively. However, the characteristics of the considered composites did not allow the production of uniform samples. The sodium silicate solution was not rapidly absorbed by the bio-aggregates; during the drying process, it was deposited on the bottom side of the samples. The uniformity of the samples is required to guarantee a correct evaluation of their performance and future homogeneous panels. Hence, different production parameters were investigated, such as drying at T
Ano: 2023
Número Páginas:
11p..
Autor(es): Cintura, E.; Faria, P.; Molari, L.; Lina Nunes
Revista: Bio-Based Building Materials
Editor: Springer
Volume:
Volume 45.
Keywords: Sodium silicate; Hazelnut shells; Bio-waste
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Testing Durability on Construction Materials
The durability of construction materials is a key concern and can be related to different actions such as weathering conditions outdoors enhanced by climatic change, chemical and biological attack, abrasion, and other conditions of service over time. Frequently, several actions develop simultaneously, making it difficult to reproduce in situ conditions in laboratory. Furthermore, testing to assess durability depends largely on the nature of the material itself or on the way it has been assembled with other materials. The ageing techniques to assess long-term durability performance of construction materials are based on accelerated durability tests, which include, for example, thermal stress, freeze
Ano: 2023
Número Páginas:
29-51pp..
Autor(es): Chastre, C.; Faria, P.; Neves, J.; Ludovico-Marques, M.; Biscaia, H.; Lina Nunes
Revista: Advances on Testing and Experimentation in Civil Engineering
Editor: Springer
Keywords: Wood; UV radiation; Frost; Weathering; Salts; Natural stone; Polymeric composites; Clayish materials; Cementitious composites; Brick; Bituminous binders and mixtures; Biological agents
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Structural gluing of portugueses timbers
This paper presents an overview of research carried out to assess the bonding suitability of Portuguese timbers.Most work developed in the last decades has focused Maritime pine timber, due to its traditional use in building construction, good mechanical properties and availability. Untreated, as well as preservative treated Maritime pine have been studied, as its impregnability allows deep treatment suitable for applications in Use Classes 3 and 4.Recent results on bonding preservative treated Maritime pine wood are discussed.Preliminary results regarding other species that are becoming available in the Portuguese market are also presented, as an attempt to reduce pressure on Maritime pine timber as well as to seek more valuable alternatives for their traditional uses.
Ano: 2018
Número Páginas:
171-183pp.
Autor(es): Cruz, H.; Martins, C.; Dias, A.
Revista: Timber: Bonds, Connections and Structures
Editor: Material Testing Institute (MPA), University of Stuttgart
Keywords: Structural gluing; Portuguese timbers
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Teses de Doutoramento
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Caracterização da aderência de varões nervurados sujeitos a ações repetidas e alternadas
No presente trabalho apresentam-se os resultados mais relevantes obtidos num programa experimental desenvolvido no LNEC com o objetivo de caracterizar a aderência dos varões nervurados do tipo A500NR SD existentes no mercado, fundamentalmente para melhorar a modelação do comportamento dos elementos de betão armado de zonas críticas de estruturas inseridas em zonas sísmicas.O programa experimental desenvolvido pretende simular as condições de aderência existentes num varão horizontal de uma ligação viga-pilar e tem como principais variáveis varões de dois diâmetros frequentemente utilizados (16 e 25 mm), dois níveis diferentes de área relativa das nervuras (A e B) e duas classes de betão (C1 e C2), ambos representativos do betão utilizado nas construções mais relevantes.Os resultados obtidos quer nos ensaios monotónicos quer nos ensaios cíclicos apontam para um decréscimo da tensão de aderência com o aumento do diâmetro da ordem dos 10%. O aumento da área relativa das nervuras transversais traduz-se num incremento da tensão máxima de aderência da ordem dos 15%, com uma redução do deslizamento que ronda os 15%. Nesse sentido, este estudo propôs que, no caso dos varões com maior área relativa das nervuras, a tensão de aderência máxima possa variar entre 2,35 e 2,65 vezes a raiz quadrada da resistência do betão à compressão e que o patamar onde a tensão de aderência é máxima se situe entre 0,5 e 1,5 mm de deslizamento.Explorou-se também o fenómeno da entrada em cedência da armadura tendo-se concluído que, em provetes que pretendem simular as condições de aderência existentes num varão horizontal de uma ligação viga-pilar, a entrada em cedência da armadura conduz a uma redução da tensão de aderência máxima inferior a 10%, quer regime monotónico quer em regime cíclico.
Ano: 2014
Número Páginas:
435p.
Autor(es): Louro, A. S.
Keywords: Estudo experimental; Modelação analítica; Ações repetidas e alternadas; Varões nervurados; Aderência
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Tratamento e consolidação de madeira de pinho degradada em elementos estruturais de edifícios antigos
O presente trabalho de investigação refere-se à conservação de elementos estruturais de madeira medianamente degradados por fungos em edifícios antigos. Propõe-se estudar a compatibilidade entre produtos de tratamento e de consolidação por impregnação, aplicados sequencialmente. A avaliação do processo foi realizada maioritariamente em laboratório e na óptica do desempenho mecânico conjunto da madeira e produtos aplicados, por intermédio de ensaios físico-mecânicos destrutivos e não destrutivos e também por ensaios mecânicos não destrutivos realizados in situ. Foram utilizados produtos comerciais, aplicando-os às espécies de madeira correntemente encontradas nos edifícios antigos da zona de Lisboa: Pinho bravo e Casquinha. Procedeu-se à avaliação mecânica de madeira nova e antiga, em estado são e degradado; ao desenvolvimento de um método de medição da profundidade de penetração de produtos de tratamento; à avaliação da capacidade consolidante de madeira degradada por produtos poliméricos fluidos e à avaliação da sua actuação conjunta, estudada com e sem envelhecimento artificial. Os resultados obtidos indicaram significativos aumentos de capacidade mecânica da madeira degradada, quando submetida a tratamento e consolidação Este trabalho desenvolve, assim, uma proposta de solução para a madeira que não se encontra sã, mas que ainda possui capacidade resistente, não necessitando, por isso, de ser removida. O processo de tratamento e consolidação promove resistência aos agentes biológicos e, simultaneamente, recuperação de alguma resistência mecânica da madeira, conferindo-lhe capacidade para continuar em serviço.
Ano: 2011
Número Páginas:
404
Autor(es): Henriques, M. D.
Keywords: Elementos estruturais; Resistência mecânica; Tratamento; Consolidação; Edifícios antigos; Conservação; Degradação por fungos; Madeira
Info
Foraging ecology of Reticulitermes grassei (clément) with re feren ce to its management as a pest of timber
Subterranean termites from the genus Reticulitermes are an important pest ofwood in service throughout southern Europe and elsewhere. For effective termitecontrol with long term protection but minimal environmental damage, newintegrated approaches to termite management are needed. Baiting-based systemsseem to be promising non-traditional methods for termite control, targeting thecolony as a whole. However, control through baiting is only feasible when it isknown that the toxicant can be transferred to all the colonies foraging on theinfested area and also throughout each individual colony. Accordingly, the workdescribed is specifically designed to achieve a better understanding of thedistribution and delimitation of colonies within a population of Reticulitermes,with parallel insights into foraging behaviour and colony organization.Initially, the species/subspecies spectrum present within the notionalReticulitermes group in Portugal was reassessed. It was shown that Reticulitermesgrassei is the only species encountered. Foraging activity was then assessed in anexperimental woodland site over two successive annual cycles, both by thesampling of natural lying dead wood and by a standard baiting grid. R. grasseiseem to select wood with larger diameter, with an apparent preference for materialalready decayed by fungi. Both termite and fungal attack on wood seems to bepromoted by higher moisture levels, such as prevail in larger litter items andduring seasonal rains. Termites were unable to detect and direct their foragingtowards sound wood in laboratory conditions, suggesting that the network ofinfochemical signals is more complex than just volatiles emanating from soundwood. Mark-release-recapture (MRR) was used to delineate foraging groups,which were then allocated to their parent colonies by the use of microsatellitemarkers. The results suggest that resource sharing is a facultative behaviour,specifically when food is not a limiting factor for colony development. Theimplications of all these findings for bait technology and protocols are discussed,with reference to the local population ecology of Reticulitermes.
Ano: 2009
Autor(es): Nobre, T.
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Relatórios
Info
Project
The project CircularBuild -
Ano: 2023
Autor(es): Lina Nunes; Duarte, M.; Duarte, S.
Keywords: Moulds; Biological durability; Subterranean termites; Decay fungi; AGEPAN® DWD PROTECT
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Monitor
Relatório final do projeto PTDC/ECM/099121/2008
Ano: 2014
Autor(es): Lina Nunes; Duarte, S.; Saporiti Machado, J.
Keywords: Deteção; Monitorização; Térmitas subterrâneas; Uso sustentável de estruturas de madeira
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Materiais metálicos. Ensaio de tracção. 2ª Parte: Verificação do sistema de medição da força da máquina de ensaio de tracção. Projecto de versão portuguesa da Norma Europeia EN 10002-2 (1991)
O presente trabalho apresenta um projecto de versão portuguesa da Norma Europeia EN 10002-2, e insere-se numa série de estudos programados pelo autor, enquanto coordenador da normalização nacional no domínio dos ensaios mecânicos, físicos e não-destrutivos de materiais metálicos.O texto do projecto de norma apresentado consiste na versão final de uma proposta redigida pelo autor, na sequência dos estudos efectuados ao nível da Comissão Técnica de Normalização competente.
Ano: 1992
Autor(es): Baptista, A. M.
Keywords: Normalização; Ensaio de tracção; Materiais metálicos
Info
Materiais metálicos. Ensaio de tracção. 5ª Parte: método de ensaio a temperatura elevada. Projecto de versão portuguesa da Norma Europeia EN 10002-5 (1991)
O presente trabalho apresenta um projecto de versão portuguesa da Norma Europeia EN 10002-5, e insere-se numa série de estudos programados pelo autor, enquanto coordenador da normalização nacional no domínio dos ensaios mecânicos, físicos e não-destrutivos de materiais metálicos.O texto do projecto de revisão apresentado consiste na versão final de uma proposta redigida pelo autor, na sequência dos estudos efectuados ao nível da Comissão Técnica de Normalização competente.
Ano: 1992
Autor(es): Baptista, A. M.
Keywords: Normalização; Ensaio de tracção; Materiais metálicos
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Metrologia de Forças. Participação do LNEC no 2nd WECC Audit on Force Measurement
O presente relatório descreve a participação do LNEC no programa europeu de intercomparação de calibrações de forças
Ano: 1992
Autor(es): Baptista, A. M.
Keywords: WECC Audit; Metrologia de forças
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Materiais metálicos. Arames. Ensaio de enrolamento. Projecto de revisão da NP 850 (1985)
O presente trabalho apresenta um projecto de revisão da Norma Portuguesa NP 850 (1985)
Ano: 1991
Autor(es): Baptista, A. M.
Keywords: Ensaio de Enrolamento; Arames; Materiais metálicos
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Materiais metálicos. Ensaios de resistência mecânica. Símbolos. Projecto de revisão da NP 386 (1965)
O presente trabalho apresenta um projecto de revisão da Norma Portuguesa NP 386 (1965)
Ano: 1991
Autor(es): Baptista, A. M.
Keywords: Normalização; Simbologia; Ensaios mecânicos; Materiais metálicos
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Materiais metálicos. Tubos. Ensaio de Abocardamento. Projecto de revisão das NP 449 (1966) e NP 451 (1966)
O presente trabalho apresenta um projecto de revisão das Normas Portuguesas NP 449 (1966)
Ano: 1991
Autor(es): Baptista, A. M.
Keywords: Normalização; Ensaio de Abocardamento; Tubos; Materiais metálicos
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Materiais metálicos. Tubos. Ensaio de Achatamento. Projecto de revisão da NP 450 (1966)
O presente trabalho apresenta um projecto de revisão da Norma Portuguesa NP 450 (1966)
Ano: 1991
Autor(es): Baptista, A. M.
Keywords: Normalização; Ensaio de Achatamento; Tubos; Materiais metálicos
Info
Materiais metálicos. Tubos. Ensaio de Dilatação de Anéis. Projecto de Norma Portuguesa
O presente trabalho apresenta um projecto de Norma Portuguesa relativo ao ensaio de dilatação de anéis de tubos metálicos, e insere-se numa série de estudos programados pelo autor, enquanto coordenador da normalização nacional no domínio dos ensaios mecânicos, físicos e não-destrutivos de materiais metálicos, com a finalidade de preencher lacunas da Normalização Portuguesa neste domínio que a indústria e as instituições ligadas ao controlo da qualidade considerem ser mais urgente colmatar.O texto apresentado consiste na versão final de uma proposta redigida pelo autor, na sequência dos estudos efectuados ao nível da Comissão Técnica de Normalização competente.
Ano: 1991
Autor(es): Baptista, A. M.
Keywords: Normalização; Ensaio de dilatação de anéis; Tubos; Materiais metálicos
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Outros
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BST 500S (A500 NR)
N/A
Ano: 2010
Número Páginas:
2pp.
Autor(es): DE/NCE
Editor: LNEC
Keywords: Varão nervurado; Varão para betão armado
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BSW 500S (A500 NR)
N/A
Ano: 2010
Número Páginas:
2pp.
Autor(es): DE/NCE
Editor: LNEC
Keywords: Varão nervurado; Varão para betão armado
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CELSA 400S (A400 NR)
N/A
Ano: 2010
Número Páginas:
2pp.
Autor(es): DE/NCE
Editor: LNEC
Keywords: Varão nervurado; Varão para betão armado
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CELSA 400SD (A400 NR de Ductilidade Especial)
N/A
Ano: 2010
Número Páginas:
2pp.
Autor(es): DE/NCE
Editor: LNEC
Keywords: Ductilidade; Varão nervurado; Varão para betão armado
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CELSA 500S (A500 NR)
N/A
Ano: 2010
Número Páginas:
2pp.
Autor(es): DE/NCE
Editor: LNEC
Keywords: Varão nervurado; Varão para betão armado
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Celsa 500SD (A500 NR de Ductilidade Especial)
N/A
Ano: 2010
Número Páginas:
2pp.
Autor(es): DE/NCE
Editor: LNEC
Keywords: Ductilidade; Varão nervurado; Varão para betão armado
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CELSA HO 500S (A500 NR)
N/A
Ano: 2010
Número Páginas:
2pp.
Autor(es): DE/NCE
Editor: LNEC
Keywords: Varão nervurado; Varão para betão armado
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CELSAMAX 500SD - CELSA ATLANTIC (A500 NR de Ductilidade Especial)
N/A
Ano: 2010
Número Páginas:
2pp.
Autor(es): DE/NCE
Editor: LNEC
Keywords: Ductilidade; Varão nervurado; Varão para betão armado
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CELSAMAX 500SD - CELSA BARCELONA (A500 NR de Ductilidade Especial)
N/A
Ano: 2010
Número Páginas:
2pp.
Autor(es): DE/NCE
Editor: LNEC
Keywords: Ductilidade; Varão nervurado; Varão para betão armado
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ÇOLAKOGLU 400S (A400 NR)
N/A
Ano: 2010
Número Páginas:
2pp.
Autor(es): DE/NCE
Editor: LNEC
Keywords: Varão nervurado; Varão para betão armado
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