Forensic Microscope

In this study, the effects of sodium carbonate (Na₂CO₃ ) solution with different concentrations (10, 15, 20, and 25 wt%) as liquid phase on the setting time and compressive strength of tricalcium silicate bone cements are investigated. The in vitro bioactivity and degradability of the resultant Ca₃SiO₅-Na₂CO₃ solution paste was also studied. The results indicate that as the concentration of Na₂CO₃ solution varies from 0 to 25 wt%, the initial and final setting time of the cement decrease significantly from 90 to 20 min and from 180 to 45min, respectively. After setting for 24 h, the compressive strength of Ca₃SiO₅-Na₂CO₃ solution paste reaches 5.1MPa, which is significantly higher than that of Ca ₃SiO₅-water cement system. The in vitro bioactivity of the cements is investigated by soaking in simulated body fluid (SBF) for 7 days. The results show that the Ca₃SiO₅-Na₂CO ₃ solution bone cement has a good bioactivity and can degrade in Ringer's solution. The results indicate that Na₂CO₃ solution as a liquid phase significantly improves the self-setting properties of Ca ₃SiO₅ cement as compared to water. The Ca₃SiO ₅ cement paste prepared using Na₂CO₃ solution shows good bioactivity and moderate degradability, and the Ca₃SiO ₅-Na₂CO₃ solution system may be used as degradable and bioactive bone defect filling materials.

This study of estimation of the sawlog volume of clear-cut stands from airborne laser scanning data considers both theoretical and factual recoveries. Theoretical sawlog volume estimates for the trees were calculated with a taper curve and factual estimates were obtained by multiplying the result by a model-based sawlog reduction factor, to allow for defects. Dominant tree species-specific models for the estimation of sawlog volumes per hectare were constructed with laser-based canopy height metrics as independent variables. The models were tested with the use of independently collected test data that consisted of 14 harvester-measured forest stands. Test data included information on the tapering of the stems and the volumes of the actually harvested assortments. The results indicate that the direct laser models are capable of producing satisfactory estimates for both the theoretical and the factual sawlog volumes of a clear-cut stand, with root mean squared errors of 9.1 and 18.0 per cent in the test data, respectively. In conclusion, the method presented here is quite suitable for pre-harvest estimation of sawlog volume, even though in cases where unpredictable defects (e.g. decay as a result of disease) exist the sawlog recoveries may be significantly overestimated.