The Experts below are selected from a list of 90 Experts worldwide ranked by ideXlab platform

I Budaiwi - One of the best experts on this subject based on the ideXlab platform.

  • modelling of Moisture and thermal transient Behaviour of multi layer non cavity walls
    Building and Environment, 1999
    Co-Authors: I Budaiwi, R Eldiasty, A Abdou
    Abstract:

    Abstract This paper describes a dynamic model for evaluating the transient thermal and Moisture transfer Behaviour in multi-layer non-cavity wall constructions. Both heat and Moisture transfer are simultaneously considered and their interactions are modelled. An implicit finite-difference scheme has been utilized to solve the temperature and air Moisture content distributions across the different layers of the wall system. The model mathematical formulations pertaining to the method of solution are described together with interstitial condensation checking and node distribution criteria for transient Moisture transfer. By employing the developed model, both the Moisture transport process and the material Moisture content within the different layers of a wall system can be evaluated at all possible material Moisture conditions. The model is validated and proven to accurately predict the Moisture Behaviour of composite walls.

  • dynamic modelling of Moisture absorption and desorption in buildings
    Building and Environment, 1993
    Co-Authors: El R Diasty, Paul Fazio, I Budaiwi
    Abstract:

    Abstract Moisture absorption and desorption by building materials in the hygroscopic range have been theoretically modelled. The Biot number which can be defined as the ratio between the material Moisture resistance to the convective mass transfer resistance has a significant meaning in relating where the greater resistance to Moisture transfer occurs. Using Biot number, the dynamic Moisture Behaviour of building materials within the indoor environment has been classified into three main categories. At high Biot number ( Bi → ∞), the material surface attains instantaneous Moisture equilibrium with the surroundings. At low Biot number ( Bi → 0), the material Moisture Behaviour can be described through a lumped-parameter modelling. For most materials in buildings, Moisture interaction with the surroundings occurs through a thin layer of material surface, and the amount of Moisture absorption or desorption is mainly determined by the material surface Moisture conditions. In order to evaluate material surface Moisture conditions, the governing Moisture transfer equation is solved via an approximate analytic technique (i.e. the moment method) in conjunction with numerical formulation. Both the dynamic and the alternating nature of the absorption/desorption processes can be modelled by this proposed analytic-numeric method. Comparison with experimental results and numerical solutions shows satisfactory agreement with the proposed model. Using this model the dynamic effect of Moisture absorption and desorption by interior materials on indoor air humidity can be modelled.

Antti Haapala - One of the best experts on this subject based on the ideXlab platform.

  • Improving the thermal performance of concrete-sandwich envelopes in relation to the Moisture Behaviour of building structures in boreal conditions
    Energy and Buildings, 2015
    Co-Authors: Filip Fedorik, Mikko Malaska, Raimo Hannila, Antti Haapala
    Abstract:

    Abstract The excellent thermal performance and low cost of concrete-sandwich walls have made them widely applied in residential buildings. However, their standard composition may require additional insulation in boreal and arctic climates, where improvements in thermal insulation are achieved mainly by applying additional insulation layers on the envelope surface. Although thick insulation will substantially improve the heat capacity of a structure, elevated temperatures and entrapped humidity can lead to favourable conditions for the initiation of mould growth. The present study simulates the thermal performance of a model house wall structure in relation to increased mould growth risk. The results indicate that added insulation may have a negative impact not only on the structure and material properties of structural elements, but also on the environmental health and comfort of residents. Furthermore, climate conditions are shown to be a significant factor in identifying an optimal insulation design based on thermal performance and structural health.

Maria Fredriksson - One of the best experts on this subject based on the ideXlab platform.

Debora Puglia - One of the best experts on this subject based on the ideXlab platform.

  • thermomechanical antioxidant and Moisture Behaviour of pva films in presence of citric acid esterified cellulose nanocrystals
    International Journal of Biological Macromolecules, 2020
    Co-Authors: Weijun Yang, Francesca Luzi, Weifu Dong, Ting Zheng, J M Kenny, Debora Puglia
    Abstract:

    Abstract In the present work, poly(vinyl alcohol) (PVA) active packaging films containing different amounts (1, 3, 5, 10 and 15% wt.) of unmodified cellulose nanocrystals (CNC) and citric acid modified cellulose nanocrystals (mCNC) were prepared by solvent casting and their effect on thermal, mechanical and wettability Behaviour of the resulted films was investigated. Results showed that both CNC and mCNC improved the thermal stability of the neat PVA matrix, but different mechanical properties and water wettability were found. Thermal stability of the materials was enhanced, by measuring shift of onset and peak temperatures that moved, respectively, from 251.5 to 298.1 °C and from 283.4 to 374.2 °C, in the case of PVA/15CNC and PVA/15mCNC films. The presence of mCNC contribute to increase the crystallinity up to 52% for PVA/10mCNC film, while it was limited to 39% for PVA/10CNC. Interestingly, PVA/mCNC composite films showed a clear UV shielding effect, while no UV resistance Behaviour was detected for PVA/CNC films. Overall migration tests revealed that the migration value was well below the legislative limits (60 mg kg−1) for food contact materials, PVA/mCNC composite films have higher radical scavenging activity than PVA/CNC films and Moisture content of PVA films containing mCNC was reduced at high RH. In conclusion, PVA/mCNC films could be considered as high-performance active food packaging materials.

Filip Fedorik - One of the best experts on this subject based on the ideXlab platform.

  • Improving the thermal performance of concrete-sandwich envelopes in relation to the Moisture Behaviour of building structures in boreal conditions
    Energy and Buildings, 2015
    Co-Authors: Filip Fedorik, Mikko Malaska, Raimo Hannila, Antti Haapala
    Abstract:

    Abstract The excellent thermal performance and low cost of concrete-sandwich walls have made them widely applied in residential buildings. However, their standard composition may require additional insulation in boreal and arctic climates, where improvements in thermal insulation are achieved mainly by applying additional insulation layers on the envelope surface. Although thick insulation will substantially improve the heat capacity of a structure, elevated temperatures and entrapped humidity can lead to favourable conditions for the initiation of mould growth. The present study simulates the thermal performance of a model house wall structure in relation to increased mould growth risk. The results indicate that added insulation may have a negative impact not only on the structure and material properties of structural elements, but also on the environmental health and comfort of residents. Furthermore, climate conditions are shown to be a significant factor in identifying an optimal insulation design based on thermal performance and structural health.