Search results for "Wood"
showing 10 items of 818 documents
Analysis of mechanical behaviour of wood species by speckle interferometry
2007
The understanding of the mechanical behaviour of wood is a very important task in modern structural engineering. This is due to the increasing role played by wood structures in modern architecture as well as to its use in the restoration of ancient buildings. However, solid mechanics of wood is very difficult since it is a complex, polymer-based, cellular, inhomogeneous material. Moreover, at the cellular scale wood is not a continuum due to the presence of vascular vacuums and it can be regarded as an anisotropic material. Conversely, at a macroscopic scale when the analysis is carried out on a structural member which is large in comparison to the size of cell, wood is usually considered a…
Experimental analysis of flexural behaviour of glued lamellar wood by speckle interferometry
2009
The smallest singular value of a shifted $d$-regular random square matrix
2017
We derive a lower bound on the smallest singular value of a random d-regular matrix, that is, the adjacency matrix of a random d-regular directed graph. Specifically, let $$C_1<d< c n/\log ^2 n$$ and let $$\mathcal {M}_{n,d}$$ be the set of all $$n\times n$$ square matrices with 0 / 1 entries, such that each row and each column of every matrix in $$\mathcal {M}_{n,d}$$ has exactly d ones. Let M be a random matrix uniformly distributed on $$\mathcal {M}_{n,d}$$ . Then the smallest singular value $$s_{n} (M)$$ of M is greater than $$n^{-6}$$ with probability at least $$1-C_2\log ^2 d/\sqrt{d}$$ , where c, $$C_1$$ , and $$C_2$$ are absolute positive constants independent of any other parameter…
Investigation on a low environmental impact solvent mixture applied to a wooden painted slab
2016
Cleaning is one of the most complex and delicate step in a restoration project, often due to the manufacturing techniques of the artifacts and their advanced state of decay. Eco-friendly solvents can permit to execute the cleaning operations with a reduced health impact for the restorers and for the environment. In this work, the performance of the 1,3- dioxolane/methylal (DIOX-MET) solvent mixture is evaluated over a wooden painted slab that had been covered with a thin layer of a protective varnish, probably during a previous conservation work performed in the Sixties. Removal of this varnish has been considered on behalf of its yellowing degradation process, which caused chromatic change…
Labile carbon alleviates wood ash effects on soil fauna
2008
The combined effects of wood ash, sucrose and oxalic acid on enchytraeid size and biomass, the abundance of microbial-feeding nematodes and pH were studied in a full three-factorial design in laboratory microcosms containing 30 g of Norway spruce forest humus. Wood ash treatment reduced enchytraeid size and abundance, but these effects were offset by sucrose without any change in pH or moisture. The positive effects of sucrose were partially counteracted by oxalic acid. Both carbon compounds increased the abundance of obligate microbial-feeding nematodes, indicating enhanced microbial production.
Bridging scales with thermodynamics: from nano to macro
2014
We have recently developed a method to calculate thermodynamic properties of macroscopic systems by extrapolating properties of systems of molecular dimensions. Appropriate scaling laws for small systems were derived using the method for small systems thermodynamics of Hill, considering surface and nook energies in small systems of varying sizes. Given certain conditions, Hill's method provides the same systematic basis for small systems as conventional thermodynamics does for large systems. We show how the method can be used to compute thermodynamic data for the macroscopic limit from knowledge of fluctuations in the small system. The rapid and precise method offers an alternative to curre…
Kirkwood–Buff Integrals Using Molecular Simulation: Estimation of Surface Effects
2020
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Woodcuts and Some Words: Edward Gordon Craig’s lasting impressions
2019
This article examines Edward Gordon Craig’s analogy between drama and wood engraving, stage and printed page in his autobiographical handbook on wood engraving, Woodcuts and Some Words (1924). Taking as a premise Craig’s interest in the world of print as materialization of his “new theatre”, it explores the semantic shift of the notion of impression from the symbolist realm of suggestion to that of modernist imprint. It finally seeks to determine the significance of engraving in Craig’s career, a medium that was the matrix, the relic and the archive of the images and of the ideal vision he pursued all his life.
On the origin and systematics of the northern African wood mouse (<i>Apodemus sylvaticus</i>) populations: a comparative study of mtDNA r…
2001
Conflicting hypotheses have been formulated regarding the origin of wood mouse (Apodemus sylvaticus) populations in northern Africa. In this study, the mtDNA restriction patterns of mice (n = 28) collected in Tunisia and Morocco are compared with those of representatives from southern Europe (n = 102). The neighbour-joining tree confirms the existence of the three lineages previously found in the Mediterranean area: western, TyrrhenianBalkan, and Sicilian. The western group is isolated from the two others, with bootstrap values of 89 and 95%. Northern African patterns are included in the western group. Their variability is low, the same pattern being shared by five Tunisian and all Morocca…
An analytical model of a new packet marking algorithm for TCP flows
2005
In Differentiated Services networks, packets may receive a different treatment according to their Differentiateo Services Code Point (DSCP) label. As a consequence, packet marking schemes can also be devised to differentiate packets belonging to a same TCP flow, with the goal of improving the performance experienced. This paper presents an analytical model for an adaptive packet marking scheme proposed in our previous work. The model combines three specific sub-models aimed at describing (i) the TCP sources aggregate, (ii) the marker, and (iii) the network status. Preliminary simulation results show quite accurate predictions for throughput and average queue occupancy. Besides, the research…