A PROPOSAL OF ESTIMATE EQUATIONS FOR FORMALDEHYDE EMISSION RATE CHANGED BY ENVIRONMAL FACTORS : A study on prediction method of indoor formaldehyde concentration based on formaldehyde emission rate measured by the test chamber method

The static headspace method using a small enclosed chamber has been extensively used to estimate the emission characteristics of formaldehyde, e.g., emission rates from building materials. The formation of the transient formaldehyde concentration by emission, diffusion and sorption in a small confined chamber was investigated using three-dimensional modelling and numerical analyses. Here, five types of glass desiccators were adopted as the small chamber for the headspace method. The inner geometries of the desiccator with the emission source (the building material) and sorbent (water in a Petri dish) were precisely modelled. Transient numerical analyses were performed to determine the formaldehyde emission from different building materials of the external (evaporative) diffusion control type, molecular diffusion and sorption on the water in the confined desiccators. In order to clarify the effect of the desiccator inner geometry on the formaldehyde emission characteristics, the equivalent diffusion length ( Ld) concept, which could be identified as the representative one-dimensional diffusion length scale, was proposed. The results of the numerical analyses showed that Ld and the formaldehyde concentration in the sorbent solution over a 24 h numerical experiment were significantly affected by the desiccator geometry. These results confirmed that the calibration of the emission rate with external diffusion control using Ld is appropriate when measuring the formaldehyde emission rate in an enclosed desiccator with different geometries.

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Study on prediction method of gas emission rate in layered mining of extremely thick coal seam

Arabian Journal of Geosciences ◽

10.1007/s12517-021-08436-x ◽

2021 ◽

Vol 14 (19) ◽

Author(s):

Chaohui Ji ◽

Meng Zhang

Keyword(s):

Coal Seam ◽

Emission Rate ◽

Prediction Method ◽

Gas Emission ◽

Thick Coal Seam

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The Influence of Thickness of Nitrocellulose Wood Lacquer on Formaldehyde Emission Rates

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.354-355.231 ◽

2011 ◽

Vol 354-355 ◽

pp. 231-235 ◽

Cited By ~ 1

Author(s):

Xue Jiao Xiao ◽

Bao Qing Deng ◽

Peng Zhang ◽

Yun Lin Zang ◽

Meng Ling Zhu ◽

...

Keyword(s):

Film Thickness ◽

Emission Rate ◽

Paint Film ◽

Formaldehyde Emission ◽

Small Scale ◽

Airflow Rate ◽

Emission Rates ◽

Double Exponential ◽

Exponential Decay Model ◽

Set Up

This study aimed to investigate the influence of the paint film thickness on formaldehyde emission rates. A small-scale environmental chamber was set up to test the formaldehyde emission from wood lacquer with different thicknesses. In all experiments, the temperature, the airflow rate and the relative humidity were the same, which were set to 23 °C, 1000 L/s, 45 %, respectively. The emission rates of formaldehyde were calculated through the double exponential decay model. Results showed that the peak concentration was dependent of the paint film thickness. The thicker the film thickness was, the slower the emission rate was.

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Study on the Prediction Method for Brittle Failure of Hard Rock Based on Acoustic Emission Test

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.594-597.376 ◽

2012 ◽

Vol 594-597 ◽

pp. 376-379 ◽

Cited By ~ 6

Author(s):

S C. Xu ◽

B R. Chen ◽

C Y. Jin

Keyword(s):

Acoustic Emission ◽

Main Shock ◽

Hard Rock ◽

Emission Rate ◽

Prediction Method ◽

Triaxial Tests ◽

True Triaxial ◽

Acoustic Emission Test ◽

Different Characteristics ◽

Ae Signals

In this paper, a series of true triaxial tests indoor with acoustic emission mornitoring were conducted and the characteristics of acoustic emission rate and energy releasing rate in the section adjacent to failure were gained. According to the different characteristics of acoustic emission rate, we divided the events rate into three types which were main shock, foreshock-main shock and cluster shocks. And then, a prediction method for hard rock was put forward according to different events rate types based on the trends of AE signals in the section adjacent to failure for hard rock.

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