An Analytical Model for Vocs Emission from Porous Building Materials

2010 ◽  
Vol 113-116 ◽  
pp. 1861-1864 ◽  
Author(s):  
Lian Ying Cao ◽  
Jun Shen
Keyword(s):  
Analytical Model ◽  
Laplace Transformation ◽  
Building Materials ◽  
Present Model ◽  
Medium Density ◽  
Porous Building Materials ◽  
Volatile Organic ◽  
Airtight Chamber ◽  
Vocs Emission ◽  
Good Agreement

This paper presented a new analytical model of partial differential equations (pde) for volatile organic compounds (vocs) emission from porous building materials. By applying Laplace transformation the representations for vocs concentration in the chamber and in the porous building material were given. The emission curves and average concentrations of some porous building materials Medium Density Fiberboards (mdf) in an airtight chamber were obtained. Result of the present model shows a good agreement with the experimental data.

An analytical model for VOCs emission from dry building materials

2004 ◽  
Vol 38 (8) ◽  
pp. 1173-1180 ◽  
Author(s):  
Baoqing Deng ◽  
Chang Nyung Kim
Keyword(s):  
Analytical Model ◽  
Building Materials ◽  
Vocs Emission

Performance Analysis and Optimization of a Dual Warhead System

2012 ◽  
Vol 13 (1) ◽  
Author(s):  
Xiao-Jun Guo ◽  
He-Ming Wen
Keyword(s):  
Experimental Data ◽  
Performance Analysis ◽  
Analytical Model ◽  
Present Model ◽  
Shaped Charge ◽  
Weapon Systems ◽  
Model Predictions ◽  
Modern Warfare ◽  
Good Agreement ◽  
Concrete Target

AbstractIn modern warfare earth penetrating weapons are often used to defeat enemy’s hardened and deeply buried targets such as aircraft shelters and bunkers. A dual warhead system (DWS) is one of such weapons composed of a forward shaped charge (FSC) and a following through warhead (FTW). In this paper, an analytical model is first proposed to analyze the penetration of an FTW into concrete targets with pre-drilled holes and a DWS is then optimized in order to achieve its best penetration performance. The effects of various parameters on the performance of a dual warhead system penetrating a concrete target are delineated. It transpires that the present model predictions are in good agreement with available experimental data and that the results obtained may be useful for designing such weapon systems.

Anomalous Diffusion during Water Absorption in Porous Building Materials – Experimental Evidence

2008 ◽  
Vol 273-276 ◽  
pp. 156-161
Author(s):  
N.M.M. Ramos ◽  
João M.P.Q. Delgado ◽  
V.P. de Freitas
Keyword(s):  
Anomalous Diffusion ◽  
Building Materials ◽  
Moisture Diffusion ◽  
Building Structures ◽  
Total Water ◽  
Clay Brick ◽  
Transform Method ◽  
Porous Building Materials ◽  
Aerated Concrete ◽  
Good Agreement

The sorption and transport of water in two porous building materials, clay brick and autoclaved aerated concrete, was studied in detail. The evolution of the distribution of liquid in the porous medium was analysed in terms of the Boltzmann transform method and anomalous diffusion equation proposed by Küntz and Lavallée [1]. The apparent moisture diffusion coefficients of water were determined from the total water profiles using a modified Boltzmann-Matano analysis, and a good agreement with literature values was found. The application of anomalous diffusion model to building materials indicates that the previous 1/ 2 t relation is not entirely accurate to estimate the volume of absorbed water. This result has particular relevance for evaluating the durability of building structures.

scholarly journals Mathematical Model of VOCs Emission in Three-layer Building Materials

2021 ◽  
Vol 257 ◽  
pp. 03047
Author(s):  
Zhehua Du ◽  
Xin Lin
Keyword(s):  
Experimental Data ◽  
Boundary Layer ◽  
Mathematical Model ◽  
Building Materials ◽  
Present Model ◽  
Transfer Resistance ◽  
Model Predictions ◽  
Layer Resistance ◽  
Boundary Layer Resistance ◽  
Good Agreement

A simple mathematical model is proposed to account for emissions of Volatile Organic Compounds (VOCs) from three-layer building materials. The model considers both the diffusion within three layer building materials and the mass transfer resistance through the air boundary layer. A general solution method based on Laplace transform is presented. Compared to other models capable of accounting for emissions of VOCs from multi layer building materials, the present model is fully analytical instead of being numerical. The present model was validated by the experimental data from the specially designed test. The results indicated that there was a good agreement between the model predictions and the experimental data. It can also be seen from calculation that model ignoring the boundary layer resistance cannot fully reflect the real situation.

Performance Analysis and Optimization of a Dual Warhead System

2012 ◽  
Vol 13 (1) ◽  
Author(s):  
Xiao-Jun Guo ◽  
He-Ming Wen
Keyword(s):  
Experimental Data ◽  
Performance Analysis ◽  
Analytical Model ◽  
Present Model ◽  
Shaped Charge ◽  
Weapon Systems ◽  
Model Predictions ◽  
Modern Warfare ◽  
Good Agreement ◽  
Concrete Target

AbstractIn modern warfare earth penetrating weapons are often used to defeat enemy’s hardened and deeply buried targets such as aircraft shelters and bunkers. A dual warhead system (DWS) is one of such weapons composed of a forward shaped charge (FSC) and a following through warhead (FTW). In this paper, an analytical model is first proposed to analyze the penetration of an FTW into concrete targets with pre-drilled holes and a DWS is then optimized in order to achieve its best penetration performance. The effects of various parameters on the performance of a dual warhead system penetrating a concrete target are delineated. It transpires that the present model predictions are in good agreement with available experimental data and that the results obtained may be useful for designing such weapon systems.

scholarly journals A semi-analytical model for diffuse reflectance in marine and inland waters

2015 ◽  
Vol 12 (4) ◽  
pp. 1893-1912 ◽  
Author(s):  
J. D. Pravin ◽  
P. Shanmugam ◽  
Y.-H. Ahn
Keyword(s):  
Optical Properties ◽  
Water Column ◽  
Analytical Model ◽  
Diffuse Reflectance ◽  
Present Model ◽  
Open Ocean ◽  
Inherent Optical Properties ◽  
Wide Range ◽  
Good Agreement

Abstract. A semi-analytical model for predicting diffuse reflectance of coastal and oceanic waters is developed based on the water-column optical properties and illumination conditions. Diffuse reflectance (R) is an apparent optical property that is related to the Gordon's parameter (bb/(a+bb)) through a proportionality factor "f". The conventional assumption of "f" as a constant (0.33) yields large errors in case of turbid and productive coastal waters and a predictive model based on this assumption is generally restricted to open-ocean waters (low chlorophyll case). In this paper, we have sorted the dependent factors that influence "f" values in the water column. Here, the parameter "f" is modeled as a function of wavelength, depth, inherent optical properties (IOPs) and illumination conditions. This work eliminates the spectral constants (KChl and KSS) associated with our previous model and constrains the present model to be solely dependent on the IOPs and illumination conditions. Data used for parameterization and validation are obtained from in situ measurements in different waters within coastal environments. Validation shows good agreement between the model R and in situ R values with the overall mean relative error of less than a few percent. The model is valid for a wide range waters within coastal and open-ocean environments.

An Analytical Model for Thermoelastic Damping in Microresonators Based on Entropy Generation

2014 ◽  
Vol 136 (3) ◽  
Author(s):  
Yongpeng Tai ◽  
Pu Li
Keyword(s):  
Analytical Model ◽  
Entropy Generation ◽  
Present Model ◽  
Stress Fields ◽  
Accurate Estimation ◽  
Solution Technique ◽  
Thermoelastic Damping ◽  
Micromechanical Resonators ◽  
Parameter Measuring ◽  
Good Agreement

This paper presents an analytical model for thermoelastic damping (TED) in micromechanical resonators, which is based on entropy generation, a thermodynamic parameter measuring the irreversibility in heat conduction. The analytical solution is derived from the entropy generation equation and provides an accurate estimation of thermoelastic damping in flexural resonators. This solution technique for estimation of thermoelastic damping is applied in beams and plates resonators. The derivation shows that the analytical expression for fully clamped and simply supported plates is similar to that for beams, but not the same as the latter due to different strain and stress fields. The present model is verified by comparing with Zener's approximation and the LR (Lifshitz and Roukes) method. The effect of structural dimensions on entropy generation corresponding to thermoelastic damping is investigated for beam resonators. The results of the present model are found to be in good agreement with the numerical and experimental results.

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