scholarly journals Moisture Buffering of Multilayer Internal Wall Assemblies at the Micro Scale: Experimental Study and Numerical Modelling

2019 ◽  
Vol 9 (16) ◽  
pp. 3438 ◽  
Author(s):  
Dobrosława Kaczorek
Keyword(s):  
Penetration Depth ◽  
Buffering Capacity ◽  
Internal Wall ◽  
Simplified Method ◽  
Buffer Value ◽  
Series Of Experiments ◽  
Overall Performance ◽  
Wall Assembly ◽  
Moisture Buffering ◽  
Moisture Buffer Value

In this paper, a series of experiments assessing the moisture buffer value (MBV) of four internal wall assembly samples made from hygroscopic materials was performed. A modified Nordtest protocol was used. Moisture buffer values of all the investigated wall assemblies, with varying moisture loads in the range of 50% to 80%, showed a moderate moisture buffer value (MBV: 0.5–1.0 (g·m−2·%RH−1)). The results showed that in a wall assembly where the MBV of the whole assembly is lower than the MBV of the outer layers, the moisture-buffering capacity of the inner layer is untapped. Outer layers affect inner layers by changing their moisture-buffering capacity, which in turn changes the overall performance of the whole assembly. In addition, it was observed that if the penetration depth value of the outer layer is greater than its thickness, vapour reaches into the deeper layer and wall assemblies made of layers with materials characterized by a lower value of penetration depth reach steady state more slowly. The WUFI Pro tool was used to compare the simulated and experimental results. Despite the discrepancies between these results, it offers a simplified method, helping designers make decisions about which materials to choose to improve the moisture-buffering effect.

Study of Moisture Buffering in Building Materials with Application of Sorption Kinetics Models

2010 ◽  
Vol 297-301 ◽  
pp. 1232-1237 ◽  
Author(s):  
N.M.M. Ramos ◽  
João M.P.Q. Delgado ◽  
V.P. de Freitas
Keyword(s):  
Building Materials ◽  
Moisture Absorption ◽  
Stationary Process ◽  
Sorption Kinetics ◽  
Temperature Level ◽  
Kinetics Models ◽  
Buffer Value ◽  
Experimental Values ◽  
Moisture Buffering ◽  
Moisture Buffer Value

This work presents experimental values of Moisture Buffer Value (MBV) obtained with three different samples of building materials, using a non-stationary process of moisture absorption. The tests carried out at the laboratory tried to explore the importance of some of the variables that can interfere in the final results, such as materials themselves, temperature level and the use of finishing coatings. The experimental data obtained at 15°C and 23°C were then analyzed using the second order sorption kinetic model. The application of kinetics models to the experimental results was explored and several parameters were retrieved. A proposal for the use of these parameters is presented and its practical use is discussed.

scholarly journals The Effects of Natural Paint on the Moisture Buffering Ability of Paper Plaster

2020 ◽  
Vol 57 (5) ◽  
pp. 51-60
Author(s):  
N. Nutt ◽  
A. Kubjas ◽  
L. Nei ◽  
A. Ruus
Keyword(s):  
Relative Humidity ◽  
Indoor Air ◽  
Waste Paper ◽  
Moisture Permeability ◽  
Daily Variations ◽  
Number Of Layers ◽  
Buffer Value ◽  
Moisture Buffering ◽  
Moisture Buffer Value

AbstractThe scope of the Nordtest method is to evaluate the moisture buffer value (MBV) of materials exposed to indoor air. The test is intended to simulate daily variations with relative humidity (RH) between 75 % during 8 hours and 33 % during 16 hours.The specimens follow a recipe that consists of waste paper, glue and water. Specimens made of paper plaster were covered with different colours.The results of the experiment showed that the type of paint used and the number of layers applied affected the MBV. Natural colours have a better moisture permeability than chemical paints, but the number of natural colour layers affects the MBV. The higher the number of layers, the lower the MBV.

scholarly journals A mathematical model for predicting the indoor moisture variation by using moisture buffering theory

2021 ◽  
Vol 2069 (1) ◽  
pp. 012036
Author(s):  
Kan Zu ◽  
Menghao Qin
Keyword(s):  
Mathematical Model ◽  
Energy Consumption ◽  
Indoor Air ◽  
Building Materials ◽  
Air Humidity ◽  
Acceptable Solution ◽  
Moisture Variation ◽  
Buffer Value ◽  
Moisture Buffering ◽  
Moisture Buffer Value

Abstract Indoor air humidity evaluation plays an of great importance role on the thermal comfort and building energy consumption. The utilization of hygroscopic materials as building materials acts on the indoor air humidity by regulating its humidity fluctuations, and then reduces a certain fraction of energy consumption on the air conditioning systems. Based on the Fick’s law, the physical process inside these hygroscopic materials requires the determinations of hygrothermal properties, which signify the extensive and reiterative experiments. While in many building simulation toolboxes, moisture buffering behavior has been evaluated by either simple approximations or complicated heat and mass model. In this case, we developed a mathematical model about the moisture transport with acceptable solution time and accuracy in terms of the moisture buffer value (MBV) theory. Considering that MBV originally represents the moisture buffering capacity of those hygroscopic materials, we did some mathematical deduction about MBVs under different boundary conditions. Then the definition of time-average MBV has been used, and all the required parameters was obtained from the practical MBV test. By comparing the new moisture buffer value model (MBM) with HAMT model, the results indicated that MBM could provide reasonably accurate prediction for indoor moisture variation.

Experimental Investigation on Rotary Punching by the Compression of Polyurethane Pad

2014 ◽  
Vol 941-944 ◽  
pp. 1802-1807 ◽  
Author(s):  
Qian Liu ◽  
Jing Tao Han ◽  
Jing Liu ◽  
Xiao Xiong Wang
Keyword(s):  
Penetration Depth ◽  
Process Parameters ◽  
High Load ◽  
Large Area ◽  
Bear Capacity ◽  
Hole Edge ◽  
Quality Degradation ◽  
Series Of Experiments ◽  
Blanking Process ◽  
The Relationship

Rotary punching is a sheet metal blanking process which utilizes shearing tools fixed to a pair of rollers. The polyurethane pad is adopted as the die instead of rigid mold because it has the advantages of wide hardness range and high load-bear capacity. Due to the application of polyurethane pad, the surrounding region adjacent to the pierced hole will occur to plastically deform and deflect, which greatly differs from that in the conventional blanking. In this paper, the effects of blank material and thickness, polyurethane hardness, punch penetration depth on deformation behavior were mathematically analyzed and modeled, and then a series of experiments through varying process parameters were conducted to validate the relationship between process parameters and product quality. The degree of sample deflection was exactly measured by scanning electron microscope (SEM). The results show that the deformed area varies with different blank elongations and increases with increasing blank thickness for a given material. When polyurethane pad with low hardness level is employed, it results in large area deformation and quality degradation. Moreover, the deflection degree around the hole edge becomes more severe along with punch penetration, but the penetration depth along blank thickness is not in proportion to the amount of punch advancement.

Verbalizable Knowledge of Skilled Task Performance

1986 ◽  
Vol 30 (5) ◽  
pp. 512-516
Author(s):  
Penelope M. Sanderson ◽  
Kim J. Vicente
Keyword(s):  
Task Performance ◽  
Question Answering ◽  
Skilled Performance ◽  
Noticeable Improvement ◽  
Series Of Experiments ◽  
Overall Performance

It has recently been shown that variables which affect skilled performance of a task can have no effect on subjects' ability to answer questions about the task and that variables which affect question answering can have no effect on skilled performance. When seen in the same task, this is termed a ‘dissociation’. However, for those concerned with the elicitation of knowledge for engineering purposes, these results are disturbing. The present paper argues that judgments of dissociation may be premature if important parts of an expert's knowledge are not being probed. A series of experiments using a simulated city transport task shows that overall performance on more detailed questionnaires generally does not improve with practice on the transport task. However, there is noticeable improvement on some individual auestions. The reasons for this are discussed.

scholarly journals Moisture Buffer Value of Building Materials

2009 ◽  
pp. 33-33-12
Author(s):  
Carsten Rode ◽  
Ruut Peuhkuri ◽  
Berit Time ◽  
Kaisa Svennberg ◽  
Tuomo Ojanen
Keyword(s):  
Building Materials ◽  
Buffer Value ◽  
Moisture Buffer Value
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