Assessment of wood surface roughness: comparison of tactile roughness and three-dimensional parameters derived using a robust Gaussian regression filter

Japanese oak and Japanese beech were sanded by hand with abrasive papers of varying grit number. Two three-dimensional parameters selected to characterize their surface roughness – one parameter for the distribution of roughness-profile peaks and the other for the relative area of the roughness-profile peaks above the threshold height – were compared against tactile roughness. The parameters were obtained from roughness profiles as determined by a robust Gaussian regression filter (RGRF) using seven cutoffs. The RGRF filtering process was adjusted specifically for the evaluation of wood surface roughness. Except for a cutoff wavelength of 0.25mm, the RGRF lent itself well to the determination of roughness profiles. No distortion of roughness profiles occurred around deep valleys, and there was a good correlation between the parameters and tactile roughness.Part of this study was presented at the 2002 Kansai Branch Office lecture meeting of the Japan Society for Precision Engineering, Kyotanabe, August 2002     

Effect of thermomechanical densification on surface roughness of wood veneers

The effect of short-term thermomechanical densification of veneer on the surface roughness and surface anatomical changes in four wood species – alder (Alnus glutinosa Gaertn.), beech (Fagus sylvatica L.), birch (Betula verrucosa Ehrh.), and pine (Pinus sylvestris L.) – was studied. Veneer sheets were densified at a temperature of 100, 150, or 200°C and at a pressure of 4, 8, or 12 MPa for 4 minutes. Seven roughness parameters such as R_a, R_z, R_q, R_p, R_v, R_sk, and R_ku were determined. Profile surface was recorded using a modified Carl Zeiss ME-10 profile gauging profilometer. Surface anatomical changes of veneer were examined using scanning electron microscopy. The results showed that densification temperature and pressure affect surface roughness of veneer. The surface became smoother, and roughness values decreased significantly (except for R_ku which increased slightly) with increasing temperature and pressure of densification. The effect of temperature on surface roughness changes is more pronounced compared with that of densification pressure. The lowest values of surface roughness were recorded for pine veneer samples followed by alder, birch, and beech samples. These results can be used to provide initial data for adhesive application processes in woodworking industry.     

Feeding responses of the western dry-wood termite <Emphasis Type="Italic">Incisitermes minor</Emphasis> (Hagen) (Isoptera: Kalotermitidae) against ten commercial timbers

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.     

沙柳重组木表面粗糙度的二维和三维分析对比

沙柳是我国东北地区广泛分布的一种速生沙生灌木,它具有耐寒、耐旱、砂埋藏高、适应性强、生长迅速等优良特性。高性能重组木是将沙柳在保留原有纤维排列的前提下,经过精细化疏解、浸胶、干燥、热压等工序加工成一种大截面、高强度、高耐候的均质结构材。作为一种建筑结构材料,其密度和尺寸可控,在一定程度上可以替代实木,大大提高了其附加值和利用率。木质材料具有独特而复杂的表面纹理,因此对其表面粗糙度进行全面的评价尤为重要。笔者研究了一种利用超景深三维显微镜测量木材表面粗糙度的新方法,主要分析了测试的特点和原理,并与传统的二维探针式表面粗糙度测量仪的结果进行了对比。此外,还研究了相对湿度对重组木表面粗糙度测量的影响。结果表明:超景深三维显微镜是一种有效测量木材表面粗糙度的方法。同时发现,高相对湿度环境对样品的表面粗糙度有不利的影响,而湿度的变化对沙柳重组木的表面纹理均匀性影响较大。并且,考虑相对湿度对测量过程的影响是十分必要的。     

Variations in compression strength and surface roughness of heat-treated Turkish river red gum (Eucalyptus camaldulensis) wood

This article reports the effects of heat treatment on compression strength parallel to the grain, the surface roughness [average roughness (R_a)], and the air-dry den-sity of wood from the river red gum tree (Eucalyptus camaldulensis Dehn.) planted in Turkey. Eucalyptus wood was heat-treated at temperatures varying from 120° to 180°C for durations of 2–10 h. Samples cut from the heat-treated wood were tested for air-dry density, compression strength parallel to grain, and surface roughness properties. Roughness measurements by the stylus method were made in the direction perpendicular to the fiber. Based on the findings in this study, the results showed that density, compression strength, and surface roughness values decreased with increasing treatment temperature and treatment times. Eucalyptus wood could be utilized by using proper heat treatment techniques without any losses in strength values in areas where working, stability, and surface smoothness, such as in window frames, are important factors.     

The influences of circular saws with sawteeth of mic-zero-degree radial clearance angles on surface roughness in wood rip sawing

Key message

The sawtooth parameters of the side edges likely affect surface roughness to a large extent in wood sawing. Our results point out the need to optimize the parameters of the side edges in order to maximize wood surface quality.

Context

Improving surface roughness of wood in rip sawing by optimizing the sawtooth parameters is a significant topic of focus in the research of wood processing. However, existing research focuses mainly on the optimization of the sawtooth parameters of the major cutting edges without taking into account the influences of length and angle of the side edges on surface roughness. Thus, adaptive parameters for the side edges should be proposed.

Aims

This study analyzes how the different parameters of side edges influence surface roughness when circular saws are used, and aims to resolve disparities between high feed speeds and better surface roughness.

Methods

In particular, this article presents the use of a sawtooth with a mic-zero-degree radial clearance angle. Northeast China ash (Fraxinus spp.) serves as the material for conducting this rip-sawing experiment. Nine types of sawtooth geometries at different feed speeds are used to study the influences of both the different radial clearance angles and the straight length of the zero-degree radial clearance angle on surface roughness (Ra).

Results

Surface roughness increases with the increase in feed speed, and the smaller the radial clearance angle of the sawteeth, the smaller the surface roughness. When the sawteeth have a mic-zero-degree radial clearance angle, the sawing surface roughness is lower than that of the value of sawteeth with radial clearance angles, especially when the straight length of the zero-degree radial clearance increases from 0 to 0.5 mm, in which case the decrease is most obvious.

Conclusion

Surface roughness depends, to a certain extent, on the depth of the saw notch. A small part of the side edge that forms the sawing surface participates in the actual cutting, and the length of this section is approximately equal to the feed per tooth. Sawteeth with mic-zero-degree radial clearance angles can improve the surface quality of sawing. Also, if the other cutting factors remain unchanged, surface roughness can be improved and friction can be reduced between the side edges and the wood by increasing the feed speed.

     

The impact of road geometry and surface roughness on fuel consumption of logging trucks

Fuel accounts for more than 35% of transport costs in Swedish forestry, and reduced fuel consumption would provide immediate economic and environmental benefits. The objective of this study was to quantify the effect of road gradient, curvature and surface roughness on fuel consumption of a conventional 60-ton logging truck. The study used a 320-km test track on both public and forest roads. The track was driven with various load weights in both dry summer and wet autumn conditions. Fuel consumption data were retrieved from the truck's CAN-bus system, and road data were measured with a profilograph. Average fuel consumption was 71.4?litres/100?km. A regression analysis showed that the most important factor was the interaction between vehicle weight and gradient, explaining the 86% increase between empty and fully loaded truck. In addition, the regression analysis quantified the individual effects of undulation, curvature and surface roughness, explaining the 107% increase in fuel consumption between the highest and lowest road class. Results from the proposed regression model (R² of 84% for a road section length of 1000?m) were consistent with predictions given by the European ARTEMIS model, and the proposed model can be used to improve cost estimation and route selection.     

The influence of silane coupling agent and poplar particles on the wet-tability,surface roughness,and hardness of UF-bonded wheat straw （Triticum aestivum L.）/poplar wood particleboard

We used silane coupling agents to improve the bonding ability between wheat straw particles and UF resin, and investigated surface properties （wettability and surface roughness） and hardness of parti-cleboard made from UF-bonded wheat straw （Triticum aestivum L.） combined with poplar wood as affected by silane coupling agent content and straw/poplar wood particle ratios. We manufactured one-layered particleboard panels at four different ratios of straw to poplar wood par-ticles （0%, 15%, 30% and 45% wheat straw） and silane coupling agent content at three levels of 0, 5% and 10%. Roughness measurements, average roughness （Ra）, mean peak-to-valley height （Rz）, and root mean square roughness （Rq） were measured on unsanded samples by using a fine stylus tracing technique. We obtained contact angle measurements by using a goniometer connected to a digital camera and computer sys-tem. Boards containing greater amounts of poplar particles had superior hardness compared to control samples and had lower wettability. Panels made with higher amounts of silane had lower Rq values.     

THE EFFECT OF WOOD SURFACE ROUGHNESS OF DIFFERENT SPECIES OF TREES ON WOOD COLOR IN WORKING OPERATION

Woodsurfaceroughnessisthemicrogeometrypropertycomposedbyalittlespacingandpeak-tovalley.Generallythesurfaceroughnesswascomposedbytheworkingmethodandotherfactorst123.Woodsurfaceroughnesswasnotonlyanimportantindexwhichmeasuredthesur-facesmoothextentofwoodproductandtheworkingqualitybutalsothewoodsur-fitceroughnessaffectedwoodsurfacefeel--lngandpsychologicalfeeling[3'4,lo,ll:.Th,'quantitativesurftlceproPertyparametersweretheimportantpartwhichmarkedthewoodsurfacevisualpsycho1ogicalmagni-tude,whichha…     

木工圆锯片锯齿侧刃参数对锯切表面粗糙度的影响

【目的】分析锯齿侧刃参数对锯切表面粗糙度的影响,通过优化锯齿侧刃参数,解决圆锯锯切时进给速度提高与表面粗糙度增大之间的矛盾,为新型木工圆锯片设计提供参考和指导。【方法】提出微量零径向侧后角锯齿的概念,使用9种不同锯齿侧刃参数的圆锯片,以水曲柳和高密度纤维板为对象进行锯切试验,研究不同进给速度下径向侧后角和零径向侧后角段对锯切表面粗糙度的影响。【结果】随着进给速度增加,锯切表面粗糙度增大,径向侧后角减小,锯切表面粗糙度降低,无零径向侧后角段锯齿锯切形成的表面粗糙度均高于具有零径向侧后角段锯齿,特别是当零径向侧后角段由0 mm增加到0.5 mm时,锯切表面粗糙度下降最为明显。当零径向侧后角段大于0.5 mm时,侧刃的零径向侧后角段具有"以锯代刨"的作用,与零径向侧后角锯齿相比同样可起到改善锯切表面质量的作用。【结论】锯切表面粗糙度一定程度上取决于锯痕深度。在实际锯切过程中,仅有长度近似等于每齿进给量的锯齿侧刃部分参与切削,占侧刃总长度的很小一部分,微量零径向侧后角锯齿中零径向侧后角段长度比每齿进给量略大且越接近每齿进给量越理想。具有微量零径向侧后角段锯齿的圆锯片与零径向侧后角锯齿相比,同样可起到改善锯切表面质量的作用;在保持其他切削参数不变的情况下,微量零径向侧后角段锯齿还可以减小锯齿侧刃与锯路壁之间的摩擦。     

Predicting spatio-temporal variability in fire return intervals using a topographic roughness index

The shapes of landscapes are fundamental to ecosystem processes at various spatial scales. Topographic roughness index (TRI) is a measure of variability in the landscape surface and a proxy of the potential of disturbances to propagate across the earth's surface, such as a wildland fire burning across a landscape. We describe the significance of TRI, present methods for calculation, and demonstrate the utility of the index in a fire frequency prediction model. The model was used to show how the relationships between topography, fire, and humans changed during the period of AD 1620–1850 for a study area (5180 km²) in Missouri, USA. The model predicted historic mean fire return intervals from TRI and two human population variables. The model explained 46% of the variation in mean fire return intervals and demonstrated that topographic roughness was most important in controlling fire frequency during the period AD 1620–1780 when human population density was lowest (<0.35 humans/km²). Due to increases in human population, mean fire return intervals were shortened by up to one-fourth of their original length and the landscape became more homogeneous with respect to fire frequency despite topographic roughness. The use of TRIs in wildland fire research aid in quantifying and visualizing topographic variability and could be applicable to multiple scales and ecosystem processes.     

Some of the properties of particleboard made from paulownia

The objective of this study was to determine some of the properties of experimental particleboard panels made from low-quality paulownia (Paulownia tomentosa). Chemical properties including holocellulose, cellulose, lignin contents, water solubility, and pH level of the wood were also analyzed. Three-layer experimental panels were manufactured with two density levels using urea–formaldehyde as a binder. Modulus of elasticity (MOE), modulus of rupture (MOR), internal bond strength (IB), screw-holding strength, thickness swelling, and surface roughness of the specimens were evaluated. Panels with densities of 0.65 g/cm³ and manufactured using a 7-min press time resulted in higher mechanical properties than those of made with densities of 0.55 g/cm³ and press times of 5 min. Based on the initial findings of this study, it appears that higher values of solubility and lignin content of the raw material contributed to better physical and mechanical properties of the experimental panels. All types of strength characteristics of the samples manufactured from underutilized low-quality paulownia wood met the minimum strength requirements of the European Standards for general uses.     

Effects of fire-retardant treatment and wood grain on three-dimensional changes of sandwich panels made from bubinga decorative veneer

ABSTRACT

The effects of a fire-retardant treatment (FRT) and wood grain on three-dimensional changes of aircraft sandwich panels were evaluated. Unvarnished and varnished panels having the outer decorative layer made with bubinga (Guibourtia spp.) were studied. Half of the samples from each type of panel received an FRT (phosphate-based) on all three layers of the decorative plywood. The other half had the two inner layers treated and the outer layer untreated. Three different figures formed by the rotary cutting and grain orientation were identified and separately studied on veneer surfaces. Samples pre-conditioned to 20°C and 40% relative humidity (RH) underwent an adsorption (25°C, 90% RH) and then a desorption (25°C, 40% RH) treatments. Changes in moisture content (MC), swelling, shrinkage, roughness, and waviness were measured after each moisture exposure condition. The results showed that the FRT increased significantly MC, swelling, and shrinkage of unvarnished and varnished panels. This treatment as well as the type of wood figure affected roughness and waviness variations of unvarnished panels. However, the effects of these two factors were not noticeable once panels were varnished.     

Friction velocityu⋆ and roughness length zo of atmospheric surface boundary layer in sparse-tree land

Sparse-tree land is one of the typical lands and can be considered as one typical rough surface in boundary layer meteorology. Many lands can be classified into the kind surface in the view of scale and distribution feature of the roughness elements such as agroforest, scatter planted or growing trees, savanna and so on. The structure of surface boundary layer in sparse-tree land is analyzed and the parameters, friction velocityu⋆and roughness length z_o are deduced based on energy balance law and other physical hypothesis. The models agree well with data of wind tunnel experiments and field measurements. This project is supported by Chinese Academy of Science Responsible editor: Chai Ruihai     

STUDY ON MEASUREMENT OF WOOD SURFACEROUGHNESS BY COMPUTER VISION

The working processes,machining devices and tools,cutting amount,consumptionof materials,productivity and quality of products are directly affected wood surface roughness.This paper gives an extensive review of methods used previously to measure wood surfaceroughness,and concludes that computer vision is the most suitable.The preliminarystudy shows that computer vinon method has the advantages of a noncontact,three--dimensionalmeasurement,high speed and well correlates with stylus tracing method.The method can be usedin classification and in-time measurement of wood surface roughness after being improved.     

Transverse shape analysis of xylem ground tissues by Fourier transform image analysis II: cell wall directions and reconstruction of cell shapes

Cell wall directions of tracheids in transverse sections of Agathis sp. and Cryptomeria japonica and fiber bodies in Magnolia obovata were quantified by Fourier transform image analysis (FTIA). Three kinds of information about cell shapes were determined from the angular distribution functions of the net map-power spectrum pattern (NM-PSP): (1) the peak angle expresses the most frequent cell wall direction, (2) the area of the peak is indicative of cell wall length, and (3) the dispersion of the peak indicates the fluctuation of cell wall orientation. Fluctuations were expressed as the standard deviation (σ) by the use of statistical analysis. Cell wall directions in Agathis, that is, directions of the tangential and radial walls (three orientations were detected) were 0° (σ = 7°), 59° (12°), 91° (9°), and 122° (12°), respectively. Pentagonal and hexagonal models were reconstructed as cell shape models in a calculated ratio of 60 : 40. On the other hand, directions were 0° (5°), 76° (12°), 89° (5°), and 102° (12°) in a calculated ratio of 45 : 55 in Cryptomeria. Fiber bodies were extracted in Magnolia and their wall directions were 0° (5°), 50° (7°), 90° (6°), and 131° (7°), respectively. The ordinary accumulated image analysis (OAIA) was checked at the same time in Agathis, and indicated that FTIA could be used as a method of reconstruction of cell shape.     

Efficacy of radio frequency treatment and its potential for control of sapstain and wood decay fungi on red oak,poplar, and southern yellow pine wood species

The effectiveness of radio frequency (RF) treatment in the control of wood decay fungi (Gloeophyllum trabeum, Ganoderma lucidum, and Irpex lacteus) and sapstain fungus (Ceratocystis fimbriata) in red oak (Quercus spp.), poplar (Populus alba), and southern yellow pine (Pinus spp.) was evaluated in the laboratory as an alternative to methyl bromide (MB) treatment. Wood samples (15.5 x 10 x 10 cm) were inoculated with fungi from a 7-day culture by dipping them to a depth of one face deep (2 cm) into inoculum and incubating them at 25°C for 14 days. Identical wood samples were left uninoculated as controls. Subsequent to incubation, the wood blocks were exposed to RF radiation in an industrial 40-kW dielectric oven at temperatures between 60° and 70°C for 2 min. The test fungi were recovered and reisolated from all of the control wood blocks but not from RF-treated wood blocks. RF treatment resulted in complete inhibition of the fungus in 98%-100% of the wood samples. Moisture content loss (≥1%) was noted after wood had been exposed to RF treatment. Moisture content may be an important factor to consider with RF treatments. RF treatment can, therefore, potentially provide an effective and rapid quarantine treatment as an alternative to MB fumigation for certain pathogen-wood combinations. This article reports the results of research only. Mention of a product does not constitute an endorsement or recommendation by USDA for its use.     

Evidence that subsistence farmers have domesticated indigenous fruits (Dacryodes edulis and Irvingia gabonensis) in Cameroon and Nigeria

Ten fruit and kernel traits were measured in 152 Irvingia gabonensis and 293 Dacryodes edulis trees from 6 villages in Cameroon and Nigeria. Frequency distribution curves were used to examine the range of variation of each trait of each species in each village and aggregated into national and regional populations. There were differences between the village sub-populations, with regard to the normality (e.g., mean kernel mass of D. edulis) or skewness (e.g., mean flesh depth of D. edulis) of the distribution curves and in the degree of separation between the individual village populations along the x axis, resulting in the development of a bimodal distribution in the regional population. For all traits, populations of both species differed significantly between countries, but only in D. edulis were there significant differences between the Cameroon populations. On the basis of the results of this study, D. edulis can be said to be virtually wild in Nigeria but semi-domesticated in Cameroon, while I. gabonensis is wild in Cameroon and semi-domesticated in Nigeria. These results are discussed with regard to a hypothesis that the range and frequency of variation in the different populations can be used to identify five stages of domestication. From a comparison of the frequency distribution curves of desirable versus undesirable traits, and statistically identifyable changes in skewness and kurtosis, it is concluded that as a result of the farmers’ own efforts by truncated selection, D. edulis is between Stages 2 and 3 of domestication (with a 67% relative gain in flesh depth) in Cameroon, while I. gabonensis in Nigeria is at Stage 2 (with a 44% relative gain in flesh depth). In this study, genetic diversity seems to have been increased, and not reduced, by domestication. This revised version was published online in June 2006 with corrections to the Cover Date.     

A comparison of selected acoustic signal analysis techniques to evaluate wood surface roughness produced during routing

This study examines the applicability of several signal analyzing methods applied to audio signals to establish relationships between audio signals generated during machining and the surface roughness produced. One-third octave passband filters were also used to condition audio signals acquired during routing of Japanese beech (Fagus crenata Blume) at different machining conditions. The one-third octave analysis was essential for gaining satisfactory results. Three different analyzing strategies were investigated: the RMS averaging method and the count rate method combined with static and dynamic thresholds. The count rate method at constant threshold could not be applied to the sound intensity signal due to its substantial range in magnitude during machining at different states, although the dynamic threshold strategy can be applied to both the sound intensity and the sound pressure signals, and adjusts flexibly to the variable signal generated. Linear regression of data obtained during each of the analyzing strategies shows that the RMS averaging method is most suitable for analyzing audio signals, as shown by its highest correlation coefficient with surface roughness produced. The results suggest that measurement of sound intensity is a promising method for monitoring surface roughness and determining optimum feed rates.     

Prediction of the surface roughness of wood for machining

The surface quality of solid wood is very important for its effective response in manufacturing processes. The effects of feed rate, cutting depth and rake angle on surface roughness and power consumption were investigated and modeled. Neuro-fuzzy methodology was applied and shown that it could be useful, reliable and an effective tool for modeling the surface roughness of wood. Thus, the results of the present research can be successfully applied in the wood industry to reduce time, energy and high experimental costs.