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1.
以两种水载铜基防腐剂季铵铜和铜唑对竹集成材进行防腐处理,分析了不同药剂和载药量对竹集成材耐腐性能的影响,以及不同干燥温度对处理材抗流失性能的影响,以筛选适宜的竹集成材防腐后处理工艺,显著提高处理材的耐久性.结果表明,经防腐处理后,竹集成材的耐腐性能大幅度提高,当季铵铜载药量≥2.6 kg/m3或铜唑载药量≥1.3 kg/m3时,竹集成材可以达到强耐腐等级;处理材的铜固着率随着载药量的增加而提高,不同干燥温度对铜的抗流失性能影响不显著.总体上看,防腐后处理工艺能够满足提高竹集成材耐久性能的要求,但其防腐剂的抗流失性能有待提高. 相似文献
2.
本文针对掺加不同外加剂的混凝土的含气量、抗冻性能、抗压强度、抗折强度等方面的试验研究,提出掺入外加剂是提高水泥混凝土路面耐久性的必要措施。 相似文献
3.
Shuichi Doi Masakazu Aoyama Shigeru Yamauchi Yasuji Kurimoto 《Journal of Wood Science》2005,51(5):526-530
We investigated the effects of high-temperature drying schedules (120°–130°C) on decay and termite feeding of Japanese larch
timbers. Thermogravimetric analysis was conducted to investigate changes of the wood components. Decay and termite feeding
tests showed that specimens dried under high-temperature schedules were susceptible against a decaying fungus Fomitopsis palustris and attacks from termites Coptotermes formosanus and Reticulitermes speratus. These drying schedules changed chemical components, which were suggested by the thermal analytical result compared to the
control sample. The results of this study indicated that the acceleration of termite feeding takes place even under temperatures
that are comparatively lower than that used in our previous research in which 170°C steaming treatment was applied to Japanese
larch wood. Decay durability against a brown rot fungus also decreased, possibly from production of low molecular weight fragments
when hemicellulose decreased during the high-temperature drying processes. 相似文献
4.
Christian Brischke Carola Hesse Linda Meyer-Veltrup Miha Humar 《Wood material science & engineering》2018,13(4):222-230
The overall aim of this study was to provide comprehensive durability characteristics of wood species underutilized but frequently occurring in Central and Northern Europe: Common juniper (Juniperus communis L.), Black cherry (Prunus serotina Ehrh.), English yew (Taxus baccata L.), and Rowan (Sorbus aucuparia L.). Decay resistance was tested against white and brown rot causing basidiomycetes and soft rot causing micro-fungi in terrestrial microcosms. Their wetting ability was determined in terms of capillary water uptake at the end-grain, the liquid water uptake during submersion, the water vapor uptake at high humidity, and the water release during drying. All tests were performed with unleached and leached specimens. Durability classes were assigned based on results from the different tests. Juniper and Yew were classified very durable (Durability class DC 1); Black cherry and Rowan were found to be less durable (DC 3–5). Leaching did not affect the durability classification significantly. Durability characteristics were completed with different indicators for the wetting ability of the four wood species. The combined effect of wetting ability and inherent decay resistance was considered for service life modeling based on a resistance model using dose–response relationships between material climate (dose) and fungal decay above ground (response). 相似文献
5.
Physical properties of pellets made from sorghum stalk, corn stover, wheat straw, and big bluestem 总被引:1,自引:0,他引:1
K. TheerarattananoonF. Xu J. WilsonR. Ballard L. MckinneyS. Staggenborg P. VadlaniZ.J. Pei D. Wang 《Industrial Crops and Products》2011,33(2):325-332
Densification of biomass feedstocks, such as pelleting, can increase bulk density, improve storability, reduce transportation costs, and make these materials easier to handle using existing handling and storage equipment for grains. The objectives of this research were to study (1) the physical properties of pellets made from corn stover, sorghum stalk, wheat straw, and big bluestem, (2) the effect of moisture content on bulk density, true density, and durability of the biomass pellets, and (3) the effect of hammer mill screen size and die thickness on bulk density, true density, and durability of the pellets. Biomass pelleting can significantly improve the bulk density from 47 to 60 kg/m3 for biomass grinds to 360 to 500 kg/m3 for biomass pellets. Of the four types of biomass pellets, wheat straw pellets had the highest bulk density value of 495.8 kg/m3, and sorghum stalk pellets had the lowest bulk density value of 365.2 kg/m3. An increase in moisture level resulted in a decrease in bulk density and true density of the pellets. The effect of moisture content on durability of the pellets made from corn stover, wheat straw, and big bluestem showed a similar trend; the maximum durability value was 96.8% at the equilibrium moisture content (EMC) range of 9% (d.b.) to 14% (d.b.) for corn stover and wheat straw, and 9% (d.b.) to 11% (d.b.) for big bluestem. A further increase in EMC value resulted in a decrease in pellet durability. For sorghum stalk pellets, the durability value increased initially with increased EMC and reached a maximum of 89.5% at EMC values between 14% (d.b.) and 16% (d.b.). Use of a larger hammer mill screen size (from 3.2 mm to 6.5 mm screen openings) resulted in increases of bulk density, true density, and durability of biomass pellets, but not in significant levels. Use of a thicker die size (from 31.8 mm to 44.5 mm in thickness) resulted in significant increase of bulk density, true density, and durability of biomass pellets. 相似文献
6.
Previously, we have reported a method for producing photochromic wool fabric by applying a thin layer of hybrid silica-photochromic
dye onto the wool surface. While the photochromic coating showed a very fast optical response and had little influence on
the fabric handle, its durability was poor. In this study, the durability of the photochromic coating layer was improved by
introducing epoxy groups into the silica matrix via co-hydrolysis and co-condensation of an alkyl trialkoxysilane compound
(ATAS) and 3-glycidoxypropyltrimethoxysilane (GPTMS). The presence of epoxy groups in the silica enhanced both washing and
abrasion durability or fastness. In addition, the optical response speed was slightly increased as well. Effects of the type
of alkyl silane and the GPTMS/alkyl silane ratio on the coating durability, fabric handle and optical response were examined. 相似文献
7.
《Wood material science & engineering》2013,8(1):34-38
Abstract Five mineral fillers were tested for wood–plastic composites (WPCs): calcium carbonate, two different types of wollastonite, soapstone and talc. The impact of the fillers on the mechanical properties of the composites was studied. The experiments included bending tests, tensile tests, Brinell hardness and scanning electron microscopy experiments. The amount of wood, mineral and plastic (polypropylene) was kept steady. Only the mineral type was changed during the tests. A control sample without any mineral added was also manufactured. The mineral addition improved the tensile strength of the WPCs. The hardness of the composite was also improved when the minerals were added, and along with the increasing mineral hardness, the hardness of the composite increased. The wollastonite acicular shape was crushed during the manufacturing process, so the phase of the process in which the minerals are added requires careful consideration. 相似文献
8.
Reaction between maleic anhydride (MA) and wood specimens was carried out in a vapor phase reaction system. Reaction conditions
such as the ratio of supplied MA to wood, initial moisture content, and reaction temperature were optimized. The MA supplied
to the reaction system was effectively absorbed by the wood, and a satisfactorily high dimensional stability was achieved
even at a low MA/wood ratio. The dimensional stability increased with rising initial moisture content. When the reaction was
conducted at an elevated temperature (180°C), high dimensional stability was attained without remarkable weight increase and
bulking. The mechanism of dimensional stabilization was discussed on the basis of the dimensional changes at high humidity
and during repeated water soaking and drying. It was shown that the dimensional stabilization arises mainly from a decrease
of hygroscopicity. When the reaction was conducted at 180°C, the formation of cross-links in the cell wall was apparent. Following
the MA treatment, the antifungal property was remarkably enhanced and met the Japanese Industrial Standard K1571. Therefore,
MA treatment in the vapor phase is an effective method to attain antifungal properties as well as high dimensional stability
with a small amount of nontoxic reagent. 相似文献
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本文从结构设计,材料学和工艺学等方面考虑原材料的性质,拌和物的配比,混凝土的结构,工艺因素,营运和气候作用等方面的相互联系,论述了影响刚性路面耐久性的因素和提高刚性路面耐久性的对策。 相似文献