Evaluation of Chemical and Morphological Properties of Spruce Wood Stored in the Natural Environment.

This paper focuses on the changes in chemical structure and fiber morphological properties of spruce wood during 15 months of its storage in an open forest woodshed. From the chemical composition, the extractives, cellulose, holocellulose, and lignin content were determined. The pH value was measured on the wood surface using a contact electrode. Acetic and formic acid, saccharides (glucose, xylose, galactose, arabinose and mannose), and polymerization degree (PD) of cellulose were analyzed using the HPLC method. Fiber length and width were determined using a fiber tester analyzer. After 15 months of storage the content of both cellulose (determined by the Seifert method) and lignin did not change; the quantity of hemicelluloses decreased by 13.2%, due to its easier degradation and less stability compared to cellulose; and the pH value dropped by one degree. HPLC analyses showed a total decrease in the cellulose DP of 9.2% and in saccharides of 40.2%, while the largest decreases were recorded in the quantity of arabinose, by 72%, in the quantity of galactose, by 61%, and in the quantity of xylose, by 43%. Organic acids were not detected due to their high volatility during wood storage. The total decrease in average fiber length was 38.2% and in width was 4.8%. An increase in the proportion of shorter fibers, and a decrease in the proportion of longer fibers, was recorded. It can be concluded that fundamental changes occurred in the wood, which could affect the quality of further products (e.g., chips, pulp, paper, particleboards).

Relation of Chemical Composition and Colour of Spruce Wood.

The visual inspection of fresh cut spruce wood (Picea abies, L. Karst.) showed the variability of its colour. Wood visual inspection is a part of wood quality assessment, for example, prior to or after its processing. The detail spruce wood colour analysis was performed using spectrophotometric data. The colour was measured by the bench-top spectrophotometer CM-5 Konica Minolta. The spectrophotometer was calibrated with a built-in white standard and on air. The whole analysis was performed in an xy chromaticity diagram supplemented with coordinate Y and CIE L*a*b* colour spaces. The ratio of the white chromophore amount to the amount of all achromatic chromophores is related to the Y coordinate. The ratio of the chromatic chromophore amount to all chromophores amount is saturation. The constructed model of the spruce wood colour is composed of four chromophores. The white chromophore belongs to holocellulose. The black chromophore belongs to lignin. The saturation is influenced by two chromophores. One of them belongs to extractives, another to lignin. The amounts of chromophores correlated with the spruce wood chemical composition. The chemical composition was measured using the procedures of Seifert, Wise, Sluiter, and ASTM. Moreover, the wood colour is affected by the moisture content.

Dry-Matter Loss and Changes in the Chemical Composition of Spruce Wood after Long-Term Storing in the Form of Roundwood.

Wood stock in a warehouse is a necessary precondition for reliable manufacturing. However, wood can degrade and lose the matter during storage. "Dry-matter loss (DML)" is used to quantify the degradation following the changes in mass of a wood substance. The proposed calculation of DML is based on using parallel figures. The calculated loss of spruce wood substance harvested in winter during a six-month period was 4.5%. The estimated annual loss of wood substance was 5.7%. The loss was caused by a factor with a gradually eliminated effect. The changes in the chemical composition of wood substance were not proportional to the original amount of the isolated chemical substances. Hemicelluloses and lignin suffered from the loss faster than there was a change in the DML of spruce wood. Hemicelluloses were the most unstable isolated compound, with an increased rate of change during the first four months. The number of extractives significantly decreased during two months of storage. However, there was an increase in the number of extractives after six months of storage. The loss of cellulose was similar to the DML of spruce wood during the whole time of storage. The FTIR analysis confirmed a decrease in the total crystalline index (TCI) and lateral order index (LOI) of cellulose due to the storage of roundwood.

Changes in Chemical Structure of Thermally Modified Spruce Wood Due to Decaying Fungi.

Fungi play a critical role in the decomposition of wood and wood-based products in use. The ability of decaying fungi to cause degradation of polysaccharides and lignin in the thermally modified Norway spruce (Picea abies L. Karst.) wood was examined with pure culture decomposition tests in laboratory conditions using the brown-rot fungus Serpula lacrymans (Schumacher ex Fries) S.F. Gray and white-rot fungus Trametes versicolor (Linnaeus ex Fries) Pilat. Spruce wood samples were primary thermally treated under atmospheric pressure at the temperatures of 100, 150, 200, 220, 240 and 260 °C during 1, 3 and 5 h, whereby larger losses in their mass, holocellulose, mannose and xylose were achieved at harder thermal regimes. Meanwhile, the holocellulose percent content reduced considerably, and the percent content of lignin increased sharply. Spruce wood thermally modified at and above 200 °C better resisted to brown-rot fungus S. lacrymans than the white-rot fungus T. versicolor. Due to the decay processes, the mass fractions of holocellulose, cellulose and hemicelluloses were lower in those spruce wood samples in which thermal degradation was more intensive, with achieving the highest mass loss values after thermal treatments, after which the decay attacks were poorer or even none with the minimal mass loss values due to action by the brown-rot fungus S. lacrymans and the white-rot fungus T. versicolor. The mannose and glucose percent content in thermally-fungally attacked spruce wood was intensive reduced, e.g., by 17% to 98% in wood after thermal treatments at temperature equal and above 200 °C.

Effect of Sunlight on the Change in Color of Unsteamed and Steamed Beech Wood with Water Steam.

This paper presents the differences in the color changes of unsteamed and steamed beech wood (Fagus sylvatica L.) caused by long-term exposure to sunlight on the surface of wood in interiors for 36 months. The light white-gray color of the yellow tinge of native beech wood darkened under the influence of sunlight, and the wood took on a pale brown color of yellow tinge. The degree of darkening and browning is quantified by the value of the total color difference ∆E* = 13.0. The deep brown-red color of steamed beech under the influence of sunlight during the exposure brightened, and the surface of the wood took on a pale brown hue. The degree of lightening of the color of steamed beech wood in the color space CIE L*a*b* is quantified by the value of the total color difference ∆E* = 7.1. A comparison of the color changes of unsteamed and steamed beech wood through the total color difference ∆E* due to daylight shows that the surface of steamed beech wood shows 52.2% smaller changes than unsteamed beech wood. The lower value of the total color difference of steamed beech wood indicates the fact that steaming of beech wood with saturated water steam has a positive effect on the color stability and partial resistance of steamed beech wood to the initiation of photochemical reactions induced by UV-VIS wavelengths of solar radiation. Spectra ATR-FTIR analyses declare the influence of UV-VIS components of solar radiation on unsteamed and steamed beech wood and confirm the higher color stability of steamed beech wood.

Chemical and Morphological Composition of Norway Spruce Wood (Picea abies, L.) in the Dependence of Its Storage.

Chemical composition and morphological properties of Norway spruce wood and bark were evaluated. The extractives, cellulose, hemicelluloses, and lignin contents were determined by wet chemistry methods. The dimensional characteristics of the fibers (length and width) were measured by Fiber Tester. The results of the chemical analysis of wood and bark show the differences between the trunk and top part, as well as in the different heights of the trunk and in the cross section of the trunk. The biggest changes were noticed between bark trunk and bark top. The bark top contains 10% more of extractives and 9.5% less of lignin. Fiber length and width depends on the part of the tree, while the average of these properties are larger depending on height. Both wood and bark from the trunk contains a higher content of fines (fibers <0.3 mm) and less content of longer fibers (>0.5 mm) compared to the top. During storage, it reached a decrease of extractives mainly in bark. Wood from the trunk retained very good durability in terms of chemical composition during the storage. In view of the morphological characteristics, it occurred to decrease both average fibers length and width in wood and bark.

Physicochemical Properties of Biobutanol as an Advanced Biofuel.

Biobutanol is a renewable, less polluting, and potentially viable alternative fuel to conventional gasoline. Biobutanol can be produced from same sources as bioethanol, and it has many advantages over the widespread bioethanol. This paper systematically analyzes biobutanol fuel as an alternative to bioethanol in alcohol-gasoline mixtures and the physicochemical properties. Based on the conducted analyses, it was found that biobutanol mixtures have a more suitable behavior of vapor pressure without the occurrence of azeotrope, do not form a separate phase in lower temperature, it has higher energy density, but slightly reduce the octane number and a have higher viscosity. However, in general, biobutanol has many advantageous properties that could allow its use in gasoline engines instead of the commonly used bioethanol.

Determination of Tractor Engine Oil Change Interval Based on Material Properties.

This article focuses on the issue of motor oils used in the engines of non-road mobile machinery (NRMM), more specifically tractors. The primary goal of the paper is to determine the appropriate replacement interval for these oils. The physical properties of the examined samples were first determined by conventional instruments. Furthermore, the concentrations of abrasive metals, contaminants, and additive elements were measured using an optical emission spectrometer. Lastly, the content of water, fuel, and glycol and the products of oxidation, nitration, and sulfation were determined by using infrared spectrometry. The measured values were compared to the limit values. Based on the processing and evaluation of these analyses, the overall condition of the oils was assessed and subsequently the optimal exchange interval of the examined oils was determined. In addition, a risk analysis of the outage was performed. Due to the high yields of crops, farmers can lose a significant amount of product when a tractor is not functioning during the harvest period. This loss is calculated in the paper.