The analysis of research results concerning heat release rates of ship materials with regard to dynamic parameters of the research station
The analysis of research results concerning heat release rates of ship materials with regard to dynamic parameters of the research station Based on the results of author's research it was stated that significant differences between heat release rates measured according to ISO 5660-1 and FTP Code Part 5 (Res. A. 653 (16)) are not caused by measurement uncertainties. A basic factor determining the lack of correlation is treating the heat release rate in the category of static measurements in the normalized measurement methods. Taking into account dynamic parameters of the test station allowed the coincidence rate (reproducibility and correlation) of the results of heat release rates measured using different methods to be improved, without changing test stations and procedures. Author's research performed on 42 materials has revealed that the relative dynamic errors of the heat release rate measurements are significant (2%÷120%). The average value of these changes for the tested group of materials was equal to 39%.
Effect of instrument response time on heat release rate measurements
A linear hereditary integral technique provides simple analytic solutions for deconvoluting thermopile and oxygen consumption data to remove the effect of instrument response time on peak and integrated heat release rate values. A comparison of corrected and uncorrected thermopile and oxygen sensor data obtained on an Ohio State University (OSU) apparatus for various materials indicates that significant errors in peak and integrated heat release rate can result from delayed instrument response to repidly changing heat flows. However, correcting for temporal effects alone using this procedure does not account for differences between heat release rate values obtained by thermopile and oxygen consumption methods.
Experimental investigation of the geotechnical properties and microstructure of lime-stabilized saline soils under freeze-thaw cycling
Abstract The Song-Nen Plain in northeastern China holds one of the three largest expanses of soda saline-alkali soil in the world. Due to its disadvantageous geotechnical properties, the saline soil in this area is unable to meet the needs of construction projects. This study evaluates the stabilizing effect of adding lime to such soils. Specifically, it investigates how the physicochemical and mechanical properties and microstructure of soda saline-alkali soil are altered by lime and how these changes are affected by both freeze-thaw cycling and the duration of curing. The results reveal that adding lime to saline soil transforms clay particles into sand and silt particles and causes the pore size distribution (PSD) to become bimodal, with small-pore and macropore populations. An increase in lime content leads to an increase in the unconfined compressive strength (UCS) but a gradual decrease in both the cation exchange capacity (CEC) and plastic index. Freeze-thaw cycles break up coarse particles and aggregate finer particles, increasing the diameter of macropores and decreasing the USC; however, the effect on specimens with >9% lime is negligible. It is further shown that the geotechnical properties of the soil change immediately after the addition of lime, indicating that the cation exchange reaction takes place very quickly. Furthermore, the pozzolanic reaction leads to an increase in the percentage of sand-sized particles and a decrease in porosity after 28 days of curing. Overall, these results indicate that it is feasible to use lime to improve the engineering properties of soda saline-alkali soil in this area.