Modeling of the emission rates of methyl ethyl ketone and effects of additives on the emission rate

Abstract

VOC(Volatile organic compound) emission rate was modelled in this study. The effects of the different environmental factors and the additives upon the emission rates were also determined. The study was conducted in a test chamber and in the field for determination of the emission rate of methyl ethyl ketone (MEK). Additionally, the theory of mass transfer was used to derive an MEK emission model with three variables (temperature, humidity, ventilation rate) and five coefficients (T ₁, R ₁, K_B , ACH_std and C_std ); these were determined by the results of emission rate in a test chamber. The emission rate of MEK ranged from 16.1 × 10³ to 101.0 × 10³ mg/m²/hr/(g‐MEK) for those cases which used solvents and plasticizer, and from 5.6×10³ to 58.1×10³ mg/m²/hr/(g‐MEK) when PVC powder was added. Additionally, the MEK emission rates increased with an increase in temperature, humidity, and ventilation rate. The mass transfer coefficients of MEK determined from the VOC emission model were approximately 0.00246 m/sec for those cases which used solvents and plasticizer, and decreased by a factor of 0.67 to 0.00164 m/sec for those cases which used solvents, plasticizer and PVC powder.     

Dynamic impedance of pile and caisson foundations

Abstract

The dynamic impedance of a pile or caisson foundation embedded in a homogeneous visco elastic half‐space was evaluated using the hybrid method. The soil‐foundation system is partitioned into a near‐field and a far‐field by choosing a cylindrical interface passing through the soil region very close to the foundation. The near‐field is modeled by the finite element method while the far‐field is characterized by a frequency‐dependent impedance matrix through the continuum approach. From the results presented, it is shown that the proposed method is very effective and can be widely used for parameter studies in engineering applications.