Volume 12 Issue 1

Potent antibacterial activities of solvent extracts (methanol:n-hexane) from the branch, leaf, and root-wood of Salvadora persica were examined against potato phytopathogenic bacteria, namely Pectobacterium carotovorum subsp. carotovorum, Dickeya solani, Ralostonia solanacerum, Enterobacter cloacae, and Bacillus pumilus. The main chemical constituents analyzed by gas chromatography–mass spectrometry (GC/MS) in the branch extracts were N-benzylbenzamide (71.08%), decane (3.17%), stigmasterol (3.17%), 9-desoxo-9-x-acetoxy-3,8,12-tri-O-acetylingol (2.33%), and β-sitosterol (2.15%). The main components in the leaf extracts were 2,6-dimethyl-N-(2-methyl-α-phenylbenzyl)aniline (28.65%), spiculesporic acid (13.60%), homo-γ-linolenic acid (12.63%), and methyl hexadecanoate (11.01%). The root-wood extracts contained, as primary parts, benzeneacetonitrile (71.47%), 4-aminocarbonyl-5-fluoro-1-α-D-ribofuranosyl-imidazole (10.99%), and benzylisothiocyanate (5.05%). The extracts from the root-wood showed moderate antibacterial activity against the potato bacterial pathogens, which was followed by leaf and branch extracts. The results suggested that S. persica plant extracts could be used as bioagents against potato soft and brown rot bacterial pathogens.

The modulus of elasticity (MOE) of wood is a sensitive indicator of rot-fungal attack. To develop an alternative method of rapid assessment of fungal decay in the laboratory, changes in static MOE of untreated and preservative-treated wood were measured during exposure to the brown-rot fungus, Gloeophyllum trabeum, and the white-rot fungus, Trametes versicolor, in a standard soil bottle assay. Static MOE loss was compared with mass loss. The results showed that the MOE of wood was a sensitive and reliable indicator of rot-fungal attack, regardless of fungus or wood species. The MOE analysis of untreated wood reduced the 12- to 16-week exposure time necessary for the standard mass loss measurement to four weeks. Also, the exposure time for preservative-treated wood was reduced to eight weeks. Untreated wood was determined to be susceptible to decay if the MOE loss was 40% or more after a four-week exposure, while treated wood was considered susceptible to decay if the MOE loss was 40% or more after an eight-week exposure.

This study examined the changes in the properties of beech wood (Fagus sylvatica L.) after intense drying. Beech wood with false red heartwood was selected as the test specimen. The test samples had dimensions of 50 mm thickness, 180 mm width, and 350 mm length. The specimens were divided into two groups, false red heartwood and sapwood. These specimens were selected with different angles of the growth rings (radial and tangential). The results showed that samples with red heartwood, in comparison to samples with sapwood content, had a remarkable effect in covering. Observation of specimens with false red heartwood and sapwood before and after drying process revealed significant differences in color changes and measured values during the covering-slicing test, but not between samples with different growth ring angles.

Combustion experiments were performed in a bubbling bed combustor to explore the effects of various oxygen concentrations (21% to 40%), temperatures (850 °C to 950 °C), and mixing ratios (0% to 30%) on the formation of NO gas. In order to correspond to different combustion stages, the generated NO were distinguished as volatile-NO and coke-NO, respectively, and the total amount and the conversion rate of NO were analyzed. The results indicated that NO comes mainly from fixed carbon combustion, and an increased oxygen concentration in the environment could produce more NO during the combustion process, regardless of the blending of biomass. The temperature increase promoted the conversion of nitrogen in the anthracite and accelerated the release of volatiles from the pine powder. During mixed combustion with increasing temperature, the volatiles formed had diluted the environmental oxygen concentration, which led to suppressed NO emissions. In addition, increasing the blending ratio also resulted in decreased NO emissions due to the large amount of intermediates released by the burning pine powder that induced a deoxidation effect on the NO emission.

Sawnwood of teak (Tectona grandis L. f.) from a Costa Rica plantation was thermally treated at different process conditions using thermo-vacuum technology. The main objectives of the study were to find the optimal combination of the process parameters, i.e. temperature (T), and duration (t), in order to minimise the colorimetric difference between sapwood and heartwood, and to evaluate the influence of the treatment on the modification pattern of physical properties of the material. The resulting mass loss (ML), hygroscopicity (H), dimensional stability (ASE), and lightness (L) were measured and compared. As expected, the temperature (T) is the main parameter influencing the extent of modification. The measured ML values turned out to be moderate even at high T values if compared with other hardwoods. The temperature range between 180 °C and 190 °C minimizes the colorimetric difference between treated sapwood and not treated heartwood.

Two raw materials, sago palm bark (SPB) and date pits, were utilized as precursors to prepare high porosity activated carbon (AC). The porosity of these two raw materials was compared with that of commercial AC made from coconut shells. The physicochemical activation method was used for AC preparation, and it consisted of two steps, carbonization and activation. The activation process was performed using zinc chloride (ZnCl2) as an activation agent. N2 adsorption-desorption analysis was carried out to characterize the porosity of AC. Thermogravimetric analysis (TGA) was conducted for the two raw materials. The adsorbent made from SPB, which showed the maximum surface area of 1634 m2/g at the 700 °C activation temperature for one hour, while the surface area of prepared AC from date pits was 1367 m2/g. Both prepared ACs had a larger surface area than commercial AC made with coconut shell (1348 m2/g).

This study explored the potential of natural light to enhance wooden interior environments. Under Nordic light, natural materials such as wood finishes present an opportunity to create warm, bright, and pleasant atmospheres, enhancing psychological well-being and comfort. The objectives of this project were twofold: first, to study the diversity of northern sky conditions in terms of cloud cover and thickness, and, second, to evaluate the impacts of the diversity of natural light on five wooden scale models. The methodology involved weather data collection that took place during the spring equinox in Quebec City. In order to create a cloudiness scale, sky condition data and photometric measurements were collected. A photographic survey occurred in five scale models made with interior wooden finishes of varying color combinations, documenting the impact of sky diversity on brightness, hue, and contrast. Simultaneous scale model studies under a real sky allowed direct comparison under the same lighting conditions. There was a remarkable diversity of visual ambiences for a southeast-oriented space depending on the position of the sun and sky conditions. Gray-dyed wooden finishes created dull and unchanging atmospheres, while yellow oaked surfaces allowed various dynamic ambiences.