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1.
Tadashi Oikawa Toshiya Matsui Yasunori Matsuda Teruko Takayama Hitoshi Niinuma Yasuyo Nishida Kazuo Hoshi Mitsuyoshi Yatagai 《Journal of Wood Science》2005,51(4):363-369
Wood is generally used as the interior material in museum storage rooms. Recently, however, the effects of volatile organic compounds (VOCs) from wood on artifacts has become a topic of great concern. The VOCs from four species of wood (western red cedar, spruce, kiri, and sugi) and their effects on artifact materials (two types of metal, seven types of pigment) were investigated using a deterioration-accelerating test, gas chromatography-mass spectrometry, X-ray diffraction analysis, and X-ray photoelectron spectroscopy. The results suggested that the influences on artifact materials varied greatly with wood species, and depended on specific components such as hinokitiol or acetic acid rather than the amount of total volatile organic compounds (TVOCs). It is a very serious problem that of the four species of wood, western red cedar (rich in hinokitiol), which has been recommended as an interior material for museum storage rooms, showed the heaviest deterioration on metal samples, and only this type of wood discolored enpaku (white lead) and rokushou (malachite, verdigris). In such storage rooms, museum artifacts should be carefully monitored. When selecting an interior material for a storage room or studying methods of preventing deterioration, it is very important to consider fully the characteristics of wood VOCs, not only the amount of TVOC.Part of this paper was presented at the 24th (Tokyo, June 2002) and 25th (Kyoto, June 2003) Annual Meeting of the Japan Society for the Conservation of Cultural Property 相似文献
2.
This study was designed to investigate the effects of moisture content (MC) and specific gravity (SG) on the bending strength and hardness of six wood species including Japanese cedar (Cryptomeria japonica D. Don), China fir (Cunninghamia lanceolata), western hemlock (Tsuga heterophylla), red meranti (Shorea spp.), Selangan batu (Shorea spp.), and red oak (Quercus spp.). The experimental results are summarized as follows: Effects of MC and SG on the strength (MOR), stiffness (MOE), and hardness (H
B) could be represented by a multiregression formulas. A negative correlation existed between these properties and MC, whereas a postive correlation showed between them and the SG. The changing rate of these properties induced by 1% MC changes varied with the wood species: 2.6% change in MOR was observed in Japanese cedar, China fir, western hemlock, red meranti, and Selangan batu; and 3.9% was found in red oak. For MOE, a 0.58% change was observed in Japanese cedar, China fir, and red meranti; western hemlock and Selangan batu exhibited 1.2% and red oak 2.5%. For hardness, a 1.1% change was observed in Japanese cedar, western hemlock, and red oak; red meranti and China fir exhibited 3.3%; and Selangan batu 1.8%.A part of this report was presented at the 48th annual meeting of the Japan Wood Research Society in Shizuoka, Japan, April 3-5, 1998 相似文献
3.
The effects of pressure and temperature on supercritical fluid impregnation of tebuconazole were evaluated on Douglas-fir,
western red cedar, red alder, white spruce, and white oak. Higher pressure markedly enhanced both the retention and distribution
of tebuconazole in these species. When the rate of pressure release was altered at the ends of treatments of Douglas-fir,
results varied. Generally, a higher rate of venting increased the steepness of the preservative gradient inward from the surface.
Elevated pressures also affected some wood properties. Western red cedar and white spruce showed collapse, while the other
three species were free of such defects. Modulus of Elasticity (MOE) and Modulus of Rupture (MOR) tended to decline with higher
pressure in western red cedar and white spruce, but the differences were rarely significant. No significant changes in MOE/MOR
occurred with the other 3 species.
Received 9 November 1998 相似文献
4.
J. Nault 《Wood Science and Technology》1988,22(1):73-80
Summary Radial distribution of thujaplicins in western red cedar (Thuja plicata Donn) trees of varying ages was studied in order to assess relative decay resistance of their wood. Samples were extracted with ethanol: benzene (1: 2), and the extractives were analyzed for thujaplicin codtent by a new method utilizing capillary gas chromatography of their methylated derivatives. The combined concentration of thujic acid and methyl thujate was also determined for each sample. Distribution of extractives, thujaplicins and thujic acid, generally increased from pith to outside heartwood, then decreased in the sapwood. Maximum extractive and thujaplicin contents were also related to tree age. This suggests that products made from the wood of younger trees will be less resistant to decay than similar products made from the wood of old trees. 相似文献
5.
Thermal treatment is an alternative to the chemical treatment in wood preservation, which has been used to some extent in
improving timber quality. Despite the enormous works done so far on the effects of heat treatment on wood properties, very
little is known about the anatomical changes in the various wood species during the process. Wood samples from western red
cedar (Thuja plicata) were heat-treated at a temperature of 220°C for 1 and 2 h. The anatomical structures were examined before and after the
heat treatment process by using scanning electron microscope (SEM) and related to density, water uptake, thickness swelling
and modulus of rupture of wood samples obtained from the same board. Heat treatment of red cedar wood resulted in the destruction
of tracheid walls, ray tissues and pit deaspiration. The destroyed tracheid walls and ray tissues appeared to blow up, thus
increasing the size of the specimen. The process of pit deaspiration also resulted in increasing size of the pits, thus creating
more openings in the wood. These changes in wood anatomy indicate that the well-established chemical degradation is not the
only reason for changes in wood properties during heat treatment. However, it is believed that the effects of the chemical
changes still outweigh those of the anatomical changes based on the modification observed during the process of heat treatment. 相似文献
6.
《Wood material science & engineering》2013,8(1):13-23
Abstract Thermal modification at elevated temperatures changes the chemical, biological and physical properties of wood. In this study, the effects of the level of thermal modification and the decay exposure (natural durability against soft-rot microfungi) on the modulus of elasticity (MOE) and modulus of rupture (MOR) of the sapwood and heartwood of Scots pine and Norway spruce were investigated with a static bending test using a central loading method in accordance with EN 408 (1995). The results were compared with four reference wood species: Siberian larch, bangkirai, merbau and western red cedar. In general, both the thermal modification and the decay exposure decreased the strength properties. On average, the higher the thermal modification temperature, the more MOE and MOR decreased with unexposed samples and increased with decayed samples, compared with the unmodified reference samples. The strength of bangkirai was least reduced in the group of the reference wood species. On average, untreated wood material will be stronger than thermally modified wood material until wood is exposed to decaying fungi. Thermal modification at high temperatures over 210°C very effectively prevents wood from decay; however, strength properties are then affected by thermal modification itself. 相似文献
7.
On the loss factor of wood during radio frequency heating 总被引：2，自引：0，他引：2
The radial direction loss factor of full-size western hemlock sapwood and heartwood, as well as western red cedar heartwood
timbers was measured using the direct calorimetric method with a laboratory-scale radio frequency/vacuum dryer at the frequency
of 13.56 MHz, moisture content range between 10 and 80%, temperature range between 25 and 55 °C, and root mean square (rms)
electrode voltages of 0.8 and 1.1 kV, respectively.
The results indicated that the moisture content, temperature, electric field strength and wood type significantly affected
the loss factor. Empirical regression equations were derived based on the experimental data that made possible the calculation
of the loss factor and power density within wood during RF heating.
Received 18 January 1997 相似文献
8.
Acidity of aqueous extracts of several tree and shrub leaf litterswas determined by titration to pH 7 with 0.01N NaOH. Bases weredetermined by back titration of 0.05N HCl extracts of groundlitters and after ashing. Lowest acidity was found in the broadleavedspecies (except sycamore) and western red cedar; greatest aciditywas found in western hemlock, grand fir, and one sample of Douglasfir. Largest contents of ash bases were found in some broadleavesplus western red cedar; the smallest contents were in most ofthe conifers. Excess ash bases (ash bases minus acidity) weregreatest in elm, hawthorn, western red cedar, hazel, willow,ash, and southern beech, and were smallest in western hemlock,Douglas fir, lodgepole pile, Sitka spruce, grand fir, hybridlarch, Scots pine, and Norway spruce. Acidity, directly titratableand ash bases, and excess ash bases showed significant, andin some cases quite large, variation between sites for somespecies. There is some support for the suggestion that excessash bases are greater in mull-forming than in mor-forming litters.Acidity was significantly greater for litters collected drythan for those collected wet. Litters which were stored airdry for several months showed increased acidity compared withtheir initial values. 相似文献
9.
J. Nault 《Wood Science and Technology》1987,21(4):311-316
Summary A quantitative method for the analysis of thujaplicins and thujic acid is described. The samples were methylated with diazomethane and analyzed using naphthalene as an internal standard. The procedure was useful in the analysis of western red cedar extractives. 相似文献
10.
This study examined the autonomy of branches with respect to the control of transpiration (E) in Douglas-fir (Pseudotsuga menziesii (Mirb.) Franco) and western red cedar (Thuja plicata Donn) seedlings. Experiments were conducted on whole seedlings in a gas exchange system with a dual-cuvette that permitted independent manipulation and measurement of E in the upper and lower cuvettes. The value of E in one cuvette was manipulated by varying vapor pressure deficit (D) between 2.2 and 0.2 kPa, whereas D in the other cuvette was held at 2.2 kPa. Reducing D, while increasing stomatal conductance (gs), resulted in an overall decrease in E. In western red cedar, this decrease was almost threefold, and in Douglas-fir, approximately fourfold. In well-watered western red cedar, a reduction of whole-plant E by 46% (brought about by reducing D in the upper cuvette) resulted in a 12% increase in gs, a 12% increase in E and a 7% increase in net assimilation (A) of untreated foliage in the lower cuvette. Responses of gs, E and A of untreated foliage were similar irrespective of whether foliage was at the top or bottom of the seedling. When D in the treatment cuvette was restored to 2.2 kPa, gs, E and A of foliage in the untreated cuvette returned to pretreatment values. In contrast, in well-watered Douglas-fir, there was almost no change in gs, E or A of untreated foliage in one cuvette when D in the other cuvette was reduced, causing a 52% reduction in whole-plant E. However, similar manipulations on drought-stressed Douglas-fir led to 7-19% increases in gs, E and A of untreated foliage. In well-watered western red cedar, daytime leaf water potential (Psil) was maintained near -0.9 MPa over a wide range of D, whereas Psil of Douglas-fir decreased from -1.2 to -1.5 MPa as D increased. The tighter (isohydric) regulation of Psil in western red cedar may partly explain its greater stomatal response to D and variation in whole-plant E compared with Douglas-fir. In response to a reduction in E, measured increases in Psil and gs of unmanipulated foliage were less than predicted by a model assuming complete hydraulic connectivity of foliage. Our results suggest the foliage of both species is partially autonomous with respect to water. 相似文献
11.
Survival after freezing was measured for seeds and germinants of four seedlots each of interior spruce (Picea glauca x engelmannii complex), lodgepole pine (Pinus contorta Dougl. ex Loud.), Douglas-fir (Pseudotsuga menziesii (Mirb.) Franco) and western red cedar (Thuja plicata Donn ex D. Donn). Effects of eight seed treatments on post-freezing survival of seeds and germinants were tested: dry, imbibed and stratified seed, and seed placed in a growth chamber for 2, 5, 10, 15, 20 or 30 days in a 16-h photoperiod and a 22/17 degrees C thermoperiod. Survival was related to the water content of seeds and germinants, germination rate and seedlot origin. After freezing for 3 h at -196 degrees C, dry seed of most seedlots of interior spruce, Douglas-fir and western red cedar had 84-96% germination, whereas lodgepole pine seedlots had 53-82% germination. Freezing tolerance declined significantly after imbibition in lodgepole pine, Douglas-fir and interior spruce seed (western red cedar was not tested), and mean LT50 of imbibed seed of these species was -30, -24.5 and -20 degrees C, respectively. Freezing tolerance continued to decline to a minimum LT50 of -4 to -7 degrees C after 10 days in a growth chamber for interior spruce, Douglas-fir and lodgepole pine, or after 15 days for western red cedar. Minimum freezing tolerance was reached at the stage of rapid hypocotyl elongation. In all species, a slight increase in freezing tolerance of germinants was observed once cotyledons emerged from the seed coat. The decrease in freezing tolerance during the transition from dry to germinating seed correlated with increases in seed water content. Changes in freezing tolerance between 10 and 30 days in the growth chamber were not correlated with seedling water content. Within a species, seedlots differed significantly in freezing tolerance after 2 or 5 days in the growth chamber. Because all seedlots of interior spruce and lodgepole pine germinated quickly, there was no correlation between seedlot hardiness and rate of germination. Germination rate and freezing tolerance of Douglas-fir and western red cedar seedlots was negatively correlated. There was a significant correlation between LT50 after 10 days in the growth chamber and minimum spring temperature at the location of seedlot origin for interior spruce and three seedlots of western red cedar, but no relationship was apparent for lodgepole pine and Douglas-fir. 相似文献
12.
13.
Yuliati Indrayani Tsuyoshi Yoshimura Yoshiyuki Yanase Yuji Imamura 《Journal of Wood Science》2007,53(3):239-248
Five Japanese timbers, four timbers from the USA, and one Malaysian timber were evaluated for their resistance to the invasive
dry-wood termite Incisitermes minor (Hagen) using laboratory choice and no-choice feeding tests with holed specimens. The highest survival rates of I. minor in both the heartwood and sapwood no-choice feeding tests were more than 70% after 3 months. When offered sapwood and heartwood
choice feeding tests and the combined choice feeding tests, the highest survival rates of I. minor were more than 75% after 3 months. With regards to the percentage of wood mass losses in the no-choice and choice feeding
tests, karamatsu (Larix leptolepsis), buna (Fagus crenata), and Douglas fir (Pseudotsuga menziesii) were classified as “resistant” species among the ten sapwood specimens. In the heartwood no-choice and choice feeding tests,
the resistant species were buna, karamatsu, Douglas fir, sugi (Cryptomeria japonica), akamatsu (Pinus densiflora), and western red cedar (Thuja plicata). The ranking of the resistance of the ten commercial timbers against I. minor was buna > karamatsu > sugi > western red cedar > Douglas fir > rubber > western hemlock > hinoki > spruce. 相似文献
14.
Tetsuya Sano Satoru Miura Hitomi Furusawa Shinji Kaneko Takahiro Yoshida Takashi Nomura Seiji Ohara 《Journal of Wood Science》2013,59(4):307-320
To evaluate the characteristics of wood ash as fertilizer, composition of inorganic elements and the leaching behavior were studied. The leaching behavior was evaluated by three leaching methods using different solvents (water, hydrochloric acid, and acetic acid: Japanese leaching test Nos. 18 and 19 and modified toxicity characteristic leaching procedure prescribed by the US Environmental Protection Agency). The ash composition varied according to raw materials for fuel and ash collection systems. Concentration of Na, Al, Si, and V became higher in bark ashes while that of K became higher in wood ashes. Pb, Cd, Se, and Zn were more volatile and enriched in fly ashes. Of the nutrient elements, K showed high water solubility and its phytoavailability also appeared high, although the amount of water-soluble K was low in bark ash. Ca and Mg had intermediate solubility while P was less soluble in both water and acetic acid. The amount of hazardous substances having leached was low for most, but not all the ashes, in terms of Pb, Cr and As. Nevertheless, the phytoavailability of these hazardous substances after their application to the forest appeared low, due to their amphoteric leaching behavior and the acidity of Japanese forest soils. 相似文献
15.
Sandor Poncsak Duygu Kocaefe Ramdane Younsi Yasar Kocaefe Louis Gastonguay 《Wood Science and Technology》2009,43(5-6):471-486
Thermal treatment is used to preserve the wood without any addition of any toxic chemicals. This process increases the dimensional stability and darkens the color of the wood. The improvement of the resistance to decay of wood by thermal treatment is also often suggested in the literature. However, some latest works contested if the durability of heat-treated wood is improved when it is used in contact with ground. The objective of this study was to investigate the possibility of thermally treating electrical poles which are larger compared to the standard wood lumber. One of the applications for thermally treated wood poles could be their use in environmental sensitive areas (along rivers, for example) as a replacement for untreated western red cedar (WRC) poles which are more expensive. Green and pre-dried red pine (Pinus resinosa) and jack pine (Pinus banksiana) poles, both with circular and square cross-sections, were heated to high temperatures under humid and inert atmosphere. Operating parameters such as maximum treatment temperature, maintenance time at this temperature, heating rate and gas humidity were varied in order to find most suitable treatment conditions for the poles. The tests showed that most of the cracks are formed during the drying process while thermal treatment only widened already existing cracks. The circular shape seems to promote crack formation during the drying period since the directional dependence of shrinking creates more stresses in circular poles compared to the square poles. A slight decrease in flexibility of the wood with increasing temperatures was observed. The protecting effect of gas humidity against oxidation of wood and the importance of the application of a moderate heating rate for poles with large cross-sections are also demonstrated in this article. The impact of the heat treatment on the resistance to decay of electrical wood pole will be presented in a future publication. 相似文献
16.
《Scandinavian Journal of Forest Research》2012,27(1-4):209-216
Seedlings of 22 species of conifers from across Canada were inoculated with m and r form isolates of the pinewood nematode (Bursaphelenchus xylophilus). In an experiment made under ambient (summer‐fall) temperatures in a shadehouse at Victoria, British Columbia, Canada, 8 of the 22 conifer species were killed by the nematodes, but mortality was low, i.e. 4–30%. Pines (eastern white, Jack and red) were more susceptible than other conifers. Yellow cypress, eastern white cedar, western red cedar and western hemlock were not killed by the nematodes. In a second experiment made at elevated temperatures (30°C‐16h long days, 25°C‐8 h long nights) in a greenhouse, 18 of the 22 conifer species died following nematode inoculation. Again, pines (lodgepole, eastern white, western white and red) were among the most susceptible tree species and the four conifers that were unaffected in the first experiment were not killed. Tamarack and western larch, both immune at ambient temperatures, were the two most susceptible conifers at elevated temperatures. Compared to ambient temperatures, seedlings at elevated temperatures died quicker and contained more nematodes. M and r form nematodes were equally pathogenic in both experiments. 相似文献
17.
Masahiro Takatani Osamu Kato Takashi Kitayama Tadashi Okamoto Mitsuhiko Tanahashi 《Journal of Wood Science》2000,46(3):210-214
The effect of steam-exploded wood flour (SE) added to wood flour/plastic composite was examined using SE from beech, Japanese cedar, and red meranti and three kinds of thermoplastic polymer: polymethylmethacrylate, polyvinyl chloride, and polystyrene. Addition of SE increased the fracture strength and water resistance of the composite board to an extent dependent on the polymer species and the composition of wood/SE/polymer. However, water resistance decreased with the increasing proportion of SE when SE meranti was added. Effects of the wood species of SE on the properties of resulting board were small. An increased moisture content of wood flour or SE (or both) increased the variation of board performance. 相似文献
18.
19.
Isoko Takahashi Takanori Sugimoto Yasuo Takasu Mariko Yamasaki Yasutoshi Sasaki Youji Kikata 《Wood Science and Technology》2012,46(1-3):419-429
The thermoplastic flow behavior of cedar flour steamed at different temperatures in the range of 160–220°C was measured using a rheometer and compared with that of beech flour. The temperature at which the cedar flour starts to flow was approximately 70°C higher than that of beech flour, and the cedar flour exhibited low flowability. Furthermore, thermoplastic moldings were prepared from cedar and beech flours, and their physical properties were examined. Similar to the case of beech, a resin-like molding with a density of approximately 1.45?g/cm3 was obtained from the cedar flour steamed at 180°C or higher, and it was revealed by SEM observation that in these moldings wood flour particles adhere to each other. The specific bending strength was maximum for the moldings obtained from 180°C-steamed flour for both types of wood. 相似文献
20.
Compressive deformation of wood impregnated with low molecular weight phenol formaldehyde (PF) resin IV: Species dependency 总被引：1，自引：0，他引：1
Flat-sawn specimens of eight wood species, albizia (Paraserianthes falkata, 0.23 g/cm3), Japanese cedar (Cryptomeria japonica, 0.31 g/cm3), red lauan (Shorea sp., 0.36 g/cm3), European spruce (Picea abies, 0.44 g/cm3), Douglas fir (Pseudotsuga douglasii, 0.50 g/cm3), elm (Ulmus sp., 0.51 g/cm3), Japanese beech (Fagus crenata, 0.64 g/cm3), and Japanese birch (Betula maximowicziana, 0.71 g/cm3), were impregnated with low molecular weight phenol-formaldehyde (PF) resin and their compressive deformations were compared.
The volume gain (VG) and weight gain due to 20% resin solution impregnation were different among species. Furthermore, the
specific volume gain (VG/specific gravity), indicating the degree of swelling of the cell wall, also varied from 17.7% for
European spruce to 26.4% for elm. Oven-dried specimens of each species were compressed using hot plates fixed to an Instron
testing machine. The deformation behavior of resin-impregnated wood up to 10MPa was significantly different among the species.
Stress development during cell wall collapse for low density wood was minimal. As a consequence, a significant increment of
density occurred up to 2MPa for low density wood such as albizia and Japanese cedar. When PF resin-impregnated wood was compressed
up to 2MPa and the pressure was kept constant for 30min, the density of Japanese cedar reached 1.18g/cm3, about 30% higher than the density of compressed Japanese birch, which possesses an original density that is 2.5 times higher
than that of Japanese cedar. The mechanical properties of resin-impregnated wood, especially low density wood, increased with
density. Hence, it is manifested that low density wood species have an advantage as raw materials for obtaining high-strength
wood at low pressing pressure. 相似文献