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  • Author: Peter Koleda x
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Abstract

The aim of the research was to verify a new method of measuring the colour of wood. The method was designed to automate wood colour measurement. In the experiments birch wood was used, which was heat treated with saturated water steam. Nikon D3200 camera was used in conjunction with the MATLAB program to implement the method. The assessments were conducted in the colour space of CIE L* a* b*. The measured values confirmed the decrease in lightness from natural to thermally modified wood. The trends of the colour values a* and b* were the same as those reported by the authors who conducted experiments with birch wood. Differences were found in the magnitude of the measured chromatic component a* values. It will be necessary to verify the above facts and determine the reasons for these differences by measuring the colour of other wood species.

Abstract

The paper deals with the research of the influence of thermal modification temperature of spruce wood on the electric energy consumption of its face milling. Samples of spruce wood heat treated at temperatures of 160, 180, 200 and 220°C were milled at the cutting speed of 20, 40 and 60 m.s-1, the feed rate of 6, 10 and 15 m.min-1, the rake angle of 15° with the depth of the cut of 1 mm. The energy consumption was evaluated from the cutting power, which was based on the difference during milling and idle cycle. The analysis of variance showed a decrease in cutting power with an increasing temperature of thermal modification. The average cutting power value is 137.7 W at the native sample and 80.8 W at the sample treated at 220°C. The Duncan’s test of statistical significance has shown that the thermal modification has a statistically significant effect on the cutting power values.

Abstract

Soil organic carbon (SOC) in agricultural land forms part of the global terrestrial carbon cycle and it affects atmospheric carbon dioxide balance. SOC is sensitive to local agricultural management practices that sum up into regional SOC storage dynamics. Understanding regional carbon emission and sequestration trends is, therefore, important in formulating and implementing climate change adaptation and mitigation policies. In this study, the estimation of SOC stock and regional storage dynamics in the Ondavská Vrchovina region (North-Eastern Slovakia) cropland and grassland topsoil between 1970 and 2013 was performed with the RothC model and gridded spatial data on weather, initial SOC stock and historical land cover and land use changes. Initial SOC stock in the 0.3-m topsoil layer was estimated at 38.4 t ha−1 in 1970. The 2013 simulated value was 49.2 t ha−1, and the 1993–2013 simulated SOC stock values were within the measured data range. The total SOC storage in the study area, cropland and grassland areas, was 4.21 Mt in 1970 and 5.16 Mt in 2013, and this 0.95 Mt net SOC gain was attributed to inter-conversions of cropland and grassland areas between 1970 and 2013, which caused different organic carbon inputs to the soil during the simulation period with a strong effect on SOC stock temporal dynamics.