Analysis of timber as sustainable material for construction

Comunicació presentada a IN-TECH 2014 International Conference on Innovative Technologies (Leiria, Portugal 10-13, september 2014).Facing the climate change scenario, professionals and technicians of civil engineering and architecture are searching for ecological solutions and construction methods that would allow for higher energy-efficiency and then reduce environmental impacts. Timber represents one of the best choices for energy-efficient construction, since it also functions as a material with good thermal transmittance properties if compared to other construction materials. This work analyses the possibilities and benefits that wood offers for the construction industry, in terms of sustainability. On the one hand, the sustainable forest management system contributes to ensure the quality and well-management in the exploitation of the forest in order to produce timber and other sub-products such as cork, paper and tree resins. In relation to this, the construction industry has an important role to increase the level of sustainable products by demanding certified timber. On the other hand, due to its Life Cycle Assessment (LCA), timber has the lower energy consumption compared to other building materials, as well as the CO2 stored and saved contributes to mitigate climate change. The LCA stages for the production of timber, the potential of saving carbon emissions and its comparison with other building products are presented. Concerning energy efficiency, once timber is implemented in a building taking part of the structure or as cladding material, it provides a high insulation decreasing the thermal transmittance of the walls, roofs, floors and windows. Its versatility as construction material also enables obtaining innovative solutions which can be implemented in buildings, as it is presented in this study. The optimum energy performance and low carbon emissions of timber make from this product a suitable and sustainable material to be highly considered for the construction industry

Material implication of Chile’s economic growth: combining material flow accounting (MFA) and structural decomposition analysis

Over the last three decades, the economic integration of the Chilean economy into global markets has been taking place at a rapid pace. For example, in 1986, exports represented 29% of GDP while in 1996 they had increased to 38% of GDP. This period of time was characterized by strong economic growth with an average annual growth rate of about 10%. From a physical perspective, material requirements more than doubled from 220 to 500 million tons of direct material inputs (DMI) during the same decade (the rate of material growth requirements was around 13% per year). The main objective of this study is to explain the changes in DMI by using a structural decomposition analysis (SDA). The changes in material flow accounting (MFA) were broken down into the effects caused by changes in resource use per unit of output (material intensity effect), changes between and within sectors (structural change effect), changes in the composition of final demand (mix effect), changes due to shifting shares of domestic final demand and export categories (category effect) and finally changes in the overall level of economic activities (level effects). The results, as a percentage of the total level of DMI used in 1986, indicate that economic growth was the major source of material changes (109%). The material intensity and category effects explained 31% and 14% of the increase, respectively. The increase in the material intensity is mainly due to a declining quality of ores in copper production. However, these components were partly compensated by the structure (− 14%) and mix (− 13%) effects. Therefore, for a Southern American country such as Chile, the main causes of these changes in material consumption have been a combination of the nature of economic growth along with an increase in export production and material intensity of production

Experimental analysis of lateral impact on planar brittle material

The fragmentation of alumina and glass plates due to lateral impact is studied. A few hundred plates have been fragmented at different impact velocities and the produced fragments are analyzed. The method employed in this work allows one to investigate some geometrical properties of the fragments, besides the traditional size distribution usually studied in former experiments. We found that, although both materials exhibit qualitative similar fragment size distribution function, their geometrical properties appear to be quite different. A schematic model for two-dimensional fragmentation is also presented and its predictions are compared to our experimental results. The comparison suggests that the analysis of the fragments' geometrical properties constitutes a more stringent test of the theoretical models' assumptions than the size distribution

Finite element analysis of a composite material interface

A finite element model of a composite material interface is developed to study the influence of the interface on the thermal strain in the composite. A plane stress model is used with an axisymmetric model as a check. The interface thickness, thermal coefficient, modulus, Poisson's ratio and the percent of mineral in the composite are variables in the study. The results confirmed the usability of the finite element model in studying the polymer-mineral interface

Surface analysis of space telescope material specimens

Qualitative and quantitative data on Space Telescope materials which were exposed to low Earth orbital atomic oxygen in a controlled experiment during the 41-G (STS-17) mission were obtained utilizing the experimental techniques of Rutherford backscattering (RBS), particle induced X-ray emission (PIXE), and ellipsometry (ELL). The techniques employed were chosen with a view towards appropriateness for the sample in question, after consultation with NASA scientific personnel who provided the material specimens. A group of eight samples and their controls selected by NASA scientists were measured before and after flight. Information reported herein include specimen surface characterization by ellipsometry techniques, a determination of the thickness of the evaporated metal specimens by RBS, and a determination of trace impurity species present on and within the surface by PIXE

Quantitative micro-luminescence analysis of lunar surface material

Quantitative microluminescence analysis of lunar glasses and fine

Bayesian changepoint analysis for atomic force microscopy and soft material indentation

Material indentation studies, in which a probe is brought into controlled physical contact with an experimental sample, have long been a primary means by which scientists characterize the mechanical properties of materials. More recently, the advent of atomic force microscopy, which operates on the same fundamental principle, has in turn revolutionized the nanoscale analysis of soft biomaterials such as cells and tissues. This paper addresses the inferential problems associated with material indentation and atomic force microscopy, through a framework for the changepoint analysis of pre- and post-contact data that is applicable to experiments across a variety of physical scales. A hierarchical Bayesian model is proposed to account for experimentally observed changepoint smoothness constraints and measurement error variability, with efficient Monte Carlo methods developed and employed to realize inference via posterior sampling for parameters such as Young's modulus, a key quantifier of material stiffness. These results are the first to provide the materials science community with rigorous inference procedures and uncertainty quantification, via optimized and fully automated high-throughput algorithms, implemented as the publicly available software package BayesCP. To demonstrate the consistent accuracy and wide applicability of this approach, results are shown for a variety of data sets from both macro- and micro-materials experiments--including silicone, neurons, and red blood cells--conducted by the authors and others.Comment: 20 pages, 6 figures; submitted for publicatio

Finite element analysis of compressible solids with nonlinear material properties

Finite-element computer program solves for nodal point displacements in an axisymmetric solid. The options in the program include plane stress analysis, axisymmetric solids analysis, nonlinear /plastic/ analysis, and equivalent stress and strain