Quantitative measurement and chemical analysis of wood dust collected in German woodworking companies

Since 1985 dust particles from beech and oak wood have been classified by the Senate Commission of the German Research Council (DFG) as being working materials which are definitely carcinogenic to humans. All other wood dusts, including those from softwoods, are classified as being materials with reasonable suspicion of carcinogenic potential. The carcinogenic principle of action remains unclear despite the partial findings of new studies. The contamination of wood dust with non-genuine substances, like heavy metals, is one of a number of possible triggering principles. This study examines wood dust collected from 33 German wood processing companies with regard to the concentration of dust in the air and its contamination with chromium, copper and boron. The machining of wood treated with preservatives occurred more often than had been expected. Other sources of wood dust contamination, apart from wood preservatives, have been identified. Woodworkers are exposed to higher levels of chromium, copper and boron than the average citizen, but these levels are far from the threshold values. The level of exposure to heavy metals seems unlikely to be the sole carcinogenic principle of action.     

Lateral cutting force during machining of wood due to momentary disturbances in the wood structure and degree of wear of the cutting tool

The paper presents a study of the effect of momentary disturbances due to variations in wood structure on the lateral cutting force. Density, shape and fibre-direction of the disturbances, and the degree of wear of the cutting tool are taken into consideration. The paper shows that high density gradients result in high lateral forces. The highest momentary lateral force noted has a value of approximately 40 N. The geometrical shape of the cutting tool in terms of degree of wear has a big impact on the lateral force. The work indicates a potential to increase the cutting performance by a more accurate supervision of the condition of the cutting tools.     

人造板厂链条式锅炉喷射砂光粉复合燃烧技术

针对人造板厂燃煤链条炉煤种适应性差、热效率普遍较低的现状,提出了将人造板生产过程的剩余物--砂光粉喷入炉膛进行悬浮燃烧,与链条炉上煤的层燃共同组成复合燃烧的技术改造方案,该项技术可显著提高链条炉的煤种适应性,改善燃烧状况,提高锅炉热效率;同时,将砂光粉作为燃料使用,不仅可以减少锅炉的燃煤消耗量,而且也可避免砂光粉对环境的污染。     

木门五金件槽孔数控加工机床的总体设计

介绍了一种木门五金件槽孔数控加工机床的总体布局、传动系统和工作台等主要机械结构的设计。用Solid Edge软件对主机机架建模并用Femap软件进行有限元分析,得到机架的位移和应力云图,表明机架强度满足设计要求。本设计大大提高了木门五金件槽孔加工的质量和生产效率,实现了木门五金件槽孔的数控加工。     

Indoor levels of polycyclic aromatic hydrocarbons in homes with or without wood burning for heating

The aim of this study was to investigate the impact of domestic wood burning on indoor levels of polycyclic aromatic hydrocarbons (PAHs). Indoor and outdoor concentrations of 27 PAHs were measured during wintertime in homes with (n= 13) or without (n 0) wood-burning appliances and at an ambient site in a Swedish residential area where wood burning for space heating is common. Twenty-four hour indoor levels of anthracene, benzo(ghi)fluoranthene, cyclopenta(cd)pyrene, benz(a)anthracene, chrysene/triphenylene, benzo(a)pyrene (BaP), indeno(1,2,3-cd)pyrene, benzo(ghi)perylene, and coronene were significantly (about 3- to 5-fold) higher in homes with, compared with homes without, wood-burning appliances. The outdoor levels of PAHs were generally higher than the indoor levelsfor all PAHs exceptforthe methylated phenanthrenes. The total PAH cancer potency (sum of BaP equivalents) was significantly higher (about 4 times) in the wood-burning homes compared with the reference homes, with BaP being the largest contributor, while phenanthrene made the largest contribution to the total PAH concentration in indoor and outdoor air. The median indoor BaP level in the wood-burning homes (0.52 ng/m3) was 5 times higher than the Swedish health-based guideline of 0.1 ng/m3, which was also exceeded outdoors on all days (median 0.37 ng/m3).     

MRI study of bread baking: experimental device and MRI signal analysis

An oven dedicated to a magnetic resonance imager (MRI) was designed and constructed for continuous monitoring of the entire baking process. The general aim was to test whether response variables conventionally measured on bread loaves, such as temperature, density, and water loss, were consistent with those reported for similar products baked in classical convection ovens. MRI images acquired during baking are presented and discussed, emphasising the need to develop quantitative MRI methods allowing conversion of the MRI signal into one variable of interest, such as local density or local water content.     

Low temperature fluidized wood chip drying with monoterpene analysis

This paper describes the drying of ponderosa pine wood chips at low (20°C and 50°C) temperatures using a bench-scale batch pulsed fluidizer to evaluate both volatile pine oils (monoterpenes) and moisture losses during drying. Ten monoterpenes were measured; anecdotal information on inter-tree differences in monoterpene composition indicate that while overall total monoterpene composition is similar for each tree, the ratios of ??-pinene, ??-pinene, ??-3-carene and limonene differ between individual trees. Results of the drying studies show normal drying curves at 20°C and 50°C; at the air flow rates used, a 20% final moisture content resulted after approximately 45 and 25 min for the two temperatures, respectively. Oil content data were highly variable but indicated that at 50°C, oils start to volatize by approximately 10 min of drying. At 20°C, oil content does not appear to change over drying time.     

Estimation of skin phototypes with optical parameters: an experimental study using newly developed fibre optic detection device

In an experimental study (October 2010 Mannheim Germany) with 99 Caucasian volunteers, the skin colour (L*, a*, b*) and the reflectance spectra of human skin were compared to the Fitzpatrick's sun‐reactive skin photo types (SPT). For this purpose, the skin colour and the reflectance spectra of human skin were determined using non‐invasive method with a newly developed fibre optic detection device. The device, based on reflectance spectroscopy, was designed and optimized using a commercial optical analysis Software. By means of the measured spectra of scattered light, the colour values and the absorption spectra of the skin were calculated. Neither any of the L*, a*, b* colour values nor any of the parameters of the absorbance spectra can be used alone to assess the skin type properly. Therefore, an ordinal logistic regression analysis was performed, using the statistical computing software r , to correlate the skin types with the measured optical parameters. It turned out that the detection device combined with the extended statistical analysis gives a better estimate of skin type in respect of the measured optical parameters than a procedure with only L*, a*, b* colour values. Even with the extended methodology, the procedure gives only a rough estimation of the skin type.     

Comparative investigation on wood production of eleven poplar clones in an experimental planting in North Greece

3 /tree respectively) in comparison to the widely cultivated clone `I-214' (1.3551 m<sup>3</sup>/tree), whereas clone `I-262' produced the lowest (0.193 m³/tree). The other clones presented a variety in volume of 0.438 to 1.662 m³/tree. The Greek clones `He-X/3' and `He-X/34' presented a lower volume (1.1662 and 1.1578 m³/tree) compared to the clone `I-214', whereas the clone `He-X/10' had a much lower one (0.438 m³/tree). It is recommended that more clones with high wood production are used for better exploitation of the microenvironmental and biological stability.

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3 /Baum) im Vergleich mit dem weit verbreiteten Klon `I-214' (1,3551 m<sup>3</sup>/Baum). Die niedrigsten Werte zeigte Klon `I-262' (0,193 m³/Baum). Die Holzmenge der übrigen Klone lag zwischen 0,438 und 1,662 m³/Baum. Die griechischen Klone `He-X/3' und `He-X/34' produzierten ebenfalls ein niedrigeres Holzvolumen (1,1662 and 1,1578 m³/Baum) als `I-214'. Die Werte des Klons `He-X/10' lagen sehr viel niedriger (0,438 m³/Baum). Es wird empfohlen, Klone mit der h?chsten Holzproduktion zu pflanzen, um die Gegebenheiten der Mikroumwelt und die biologischen Stabilit?t besser zu nutzen.

     

Improving Wood/Polypropylene fiberboards properties with an original MAPP coating process

In this work, which is part of a project about WPC fibreboard (Wood Polymer Composites) with post mouldable ability, we focused on the role of interface modification in improving physical and mechanical properties. To reach these goals, an original coating process was developed. Rather than randomly disperse a coupling agent powder in the mat, the coupling agent was aimed at the interface by coating MAPP onto PP fibre, which is less important in quantity than natural fibre in our WPC. In that way the bonding improvement was concentrated at the interface where the stress transfer occurs. Results of internal bond, flexion and tensile testing showed improvements of WPC fibreboards mechanical characteristic. SEM corroborated the presence of MAPP coating and validated experimental process.     

戊唑醇和IPBC防腐处理材的FTIR分析

分别经戊唑醇和3-碘-2-丙炔基丁基氨基甲酸丁酯(IPBC)防腐剂处理的杉木、马尾松,采用傅立叶红外光谱(FTIR),对戊唑醇和IPBC在木材内的结合状况进行分析.结果表明,杉木、马尾松和戊唑醇或IPBC防腐剂没有发生任何化学官能团的结合,仅仅是靠物理吸附作用留着在木材中.     

含胶类纤维成膜装置的设计及实验

针对现有含胶类纤维成膜装置所存在的缺陷,研制了新型的含胶类纤维成膜装置,并阐述了其制作方法.实践证明:此装置结构简单,操作简便、快速,可循环利用水,节约资源,环保,具有较高的应用及推广价值.     

Photostability of white oak wood stained with metal salts during indoor sunlight exposure

Wood products that are used in indoor environments can be exposed during their use to UV–vis light through window glass. Exposure of wood products to UV–vis light can cause discoloration due to changes in structures of wood components such as extractives and lignin. In this study, the color stability during artificial aging of white oak wood stained with iron (III) and nickel (II) salts with and without a standard UV-curable finishing system was evaluated for indoor applications. To do so, color measurements were performed at different stages of the aging process. Fourier transform mid and near infrared and X-ray photoelectron spectroscopies were used to compare the rate of degradation of wood and to analyze the metals on wood’s surface. The results of this study showed that the addition of metal ions to wood had a photoprotective effect on lignin’s degradation during the first stages of artificial aging. Higher protection of lignin was shown for nickel (II) acetate-stained wood at 4% w/v. During the first 24 h, Δa* and Δb* increased for all uncoated samples, which indicates that the color of wood surface was modified to redder and yellower hues. For wood stained with iron (III) sulfate, the color of wood samples shifted from blue to dark brown. The addition of a standard UV-curable finishing system decreased the color changes for all samples. For nickel-stained wood, color changes were not perceptible after the first 24 h of aging with a UV-curable finishing system in contrary to iron-stained wood.