Effect of drying temperature on surface roughness of oak (Quercus petraea ssp. iberica (Steven ex Bieb) Krassiln) Veneer

This paper reports the effect of various drying temperatures on the surface roughness (SR) characteristics of veneer samples. Three SR parameters [average roughness (R_a), average maximum height of the profile (R_z), and root mean square roughness (R_q)] were measured on sliced veneer obtained from Oak logs (Quercus petraea ssp. iberica (Steven ex Bieb) Krassiln). The sliced veneers were dried at 100, 115 and 130 °C drying temperatures for 2 min. Roughness measurements were taken from the surface of the samples in across the grain orientation of the veneer. The results showed that the effect of drying temperatures used in practice is statistically significant on SR of the sliced veneers.     

The effects of some manufacturing factors on surface roughness of sliced Makoré (Tieghemella heckelii Pierre Ex A.Chev.) and rotary-cut beech (Fagus orientalis L.) Veneers

In this study, the effects of veneer thickness, cutting speed, knife bevel, vertical and horizontal opening, and drying temperature on surface roughness of sliced Makore veneer and rotary-cut beech veneer were evaluated. Makore logs for sliced veneers and beech logs were used for rotary-cut veneers manufacturing. Before veneer manufacturing, the Makore and beech logs were steamed indirectly at 80 °C for 50 and 36 h, respectively. Roughness measurements were conducted according to DIN standard 4768 by using stylus profilometer. The sliced radial and tangential veneers were grouped and evaluated separately. Results showed that veneer thickness, cutting speed and knife bevel had a significant effect on surface roughness for the sliced veneers, but veneer drying temperature did not affect significantly the surface roughness. In general, surface roughness of the veneer increases with increasing veneer thickness. However, increases in cutting speed decreased the surface roughness. The most suitable knife bevel was 17.5° for manufacturing sliced veneers from Makore. For rotary-cut veneers, vertical and horizontal opening had a significant effect on the surface roughness. The results indicated that vertical opening should be about 50% and horizontal opening about 80–90% of veneer thickness to minimize the surface roughness in manufacturing rotary cut veneer from oriental beech.     

Evaluation of surface roughness of Thai medium density fiberboard (MDF)

Wood composites contain irregularities on their surface due to the sanding process which play an important role when they are used as substrate for thin overlays. The objective of this study is to evaluate surface characteristics of commercially manufactured medium density fiberboard (MDF) panels in Thailand. A skid type profilometer with diamond stylus of 5 μm tip radius and 90° tip angle was employed for the experiment. Roughness average (R_a), average maximum height of the profile (R_z), and maximum roughness depth (R_max) were used to evaluate quantitatively surface characteristics of the specimens. Roughness measurements were taken from both sides of the sanded specimens along and across the sandmarks over 15.2 mm tracing span. Panel type-C had the smoothest surface with average values of 2.39, 21.03, and 26.93 μm for R_a, R_z, and R_max, respectively. It was found that no statistically (p<0.1$p<0.1$) significant difference existed between the values of all three parameters taken in both sandmark directions of all types of panels. Also none of the panels considered in this study had superior surface quality over the other. In further studies, surface roughness of MDF samples exposed to various relative humidity levels could give a better understanding of their roughness behavior for different overlaying applications.     

Effect of machining on surface roughness of wood

The objective of this study is to evaluate effect of various machining techniques on the surface roughness of beech (Fagus orientalis) and aspen (Populus tremula  ) lumber. Surface characteristics of sawn, planed, and sanded samples of both species were determined employing a stylus type profilometer. Average roughness (_Ra$R_{\mathrm{a}}$), mean peak-to-valley height (_Rz$R_{\mathrm{z}}$), core roughness depth (_Rk$R_{\mathrm{k}}$), reduced peak height (_Rpk$R_{\mathrm{pk}}$), and reduced valley depth (_Rvk$R_{\mathrm{vk}}$) roughness parameters were used to determine surface characteristics of the samples. Based on the results of statistical analysis, measurements taken from the surface in tangential and radial directions of both species did not result in significant difference at a 95% confidence level. However, significant statistical difference was found between surface characteristics of aspen and beech samples, machined with four different ways in both grain orientations. This study suggests that stylus method can be successfully used to evaluate and distinguish variations on the surface of wood, due to grain orientation and planning and sanding. Data generated in this study can be used as a quality control tool for further processes such as finishing or gluing of wood from two species.     

Effects of logs steaming,veneer drying and aging on the mechanical properties of laminated veneer lumber (LVL)

In this study the effects of steaming and drying condition on the mechanical properties and durability of laminated veneer lumber (LVL) and solid sawn lumber were investigated in a comparative way. Steamed beech and steamed and non-steamed spruce logs were used and two different veneer drying temperatures (20 and 110 °C) were selected for this aim. Aging test was applied according to EN 321 to determine the durability of LVL and solid wood samples. Steaming decreased considerably all investigated strength properties of LVL panels and the least affected was the compression strength. The compression strength and the static bending strength values of both beech and spruce LVL panels were higher than those of the solid wood groups obtained from the same logs. The impact strength values of LVL panels, unlike the static bending strength and the compression strength, were lower than those of the solid samples, which were not steamed and aged.     

Surface characteristics of wood composites manufactured in Thailand

The objective of this study is to evaluate surface characteristics of commercially manufactured particleboard and medium density fiberboard (MDF) panels in Thailand. The surface roughness of both type of panels were measured using a fine stylus technique. Average roughness (R_a), mean peak-to-valley height (R_z), and maximum roughness (R_max) were used to evaluate quantitatively surface characteristics of the specimens. Roughness measurements were taken from both sides of the specimens along and across the sandmarks. It was found that no statistically (p<0.1) significant difference existed between the values of all three parameters taken in two directions. The results showed that panel types C and B had better roughness values that those of panel types A and B for MDF and particleboard, respectively. None of the panels considered within the same type in this study had superior surface quality over the other.     

Accuracy and precision of Legionella isolation by US laboratories in the ELITE program pilot study

A pilot study for the Environmental Legionella Isolation Techniques Evaluation (ELITE) Program, a proficiency testing scheme for US laboratories that culture Legionella from environmental samples, was conducted September 1, 2008 through March 31, 2009. Participants (n = 20) processed panels consisting of six sample types: pure and mixed positive, pure and mixed negative, pure and mixed variable. The majority (93%) of all samples (n = 286) were correctly characterized, with 88.5% of samples positive for Legionella and 100% of negative samples identified correctly. Variable samples were incorrectly identified as negative in 36.9% of reports. For all samples reported positive (n = 128), participants underestimated the cfu/ml by a mean of 1.25 logs with standard deviation of 0.78 logs, standard error of 0.07 logs, and a range of 3.57 logs compared to the CDC re-test value. Centering results around the interlaboratory mean yielded a standard deviation of 0.65 logs, standard error of 0.06 logs, and a range of 3.22 logs. Sampling protocol, treatment regimen, culture procedure, and laboratory experience did not significantly affect the accuracy or precision of reported concentrations. Qualitative and quantitative results from the ELITE pilot study were similar to reports from a corresponding proficiency testing scheme available in the European Union, indicating these results are probably valid for most environmental laboratories worldwide. The large enumeration error observed suggests that the need for remediation of a water system should not be determined solely by the concentration of Legionella observed in a sample since that value is likely to underestimate the true level of contamination.     

Machining properties and surface roughness of various wood species planed in different conditions

This study was carried out to determine the planing properties and surface roughness of naturally grown Oriental beech (Fagus orientalis Lipsky.), Anatolian chestnut (Castenea sativa Mill), Black alder (Alnus glutinosa subsp. Barbata (C.A.Mey.) Yalt.), Scotch pine (Pinus sylvestris L.), and Oriental spruce (Picea orientalis (L.) Link.) grown in the eastern Black sea region of Turkey. The tests were conducted according to ASTM 1666 and DIN 4768. Test specimens were prepared from the lumber cut tangentially from logs. The machining process was carried out on a cabinet planer machine. Mainly, the effects of the rake angle and the feed speed were investigated. The cutting depth was constant with 1.6 mm. The Oriental spruce resulted in the lowest machining performance among the samples. The machining performance of the specimen increased as the feed speed or the rake angle decreased. All of the samples except the Anatolian chestnut showed lower surface roughness values. The surface roughness is found not to be affected by the feed speed, but by the rake angle. In addition, lower surface roughness values were observed for the latewood than the earlywood.     

Evaluation of surface characteristics of laminated flooring

In this study, surface characteristics of commercially manufactured laminated flooring were evaluated. The surface roughness of samples consisting of high-density fiberboard (HDF) base and melamine resin saturated paper overlay was investigated. Here, 10 cm×10 cm samples of two types of panels were used for the experiments. A fine stylus technique was employed for the measurements. Three roughness parameters, namely average roughness (_Ra$R_{\mathrm{a}}$), mean peak to valley height (_Rz$R_{\mathrm{z}}$), and maximum roughness (_Rmax$R_{\max }$) were considered to determine roughness of the flooring panels. It was found that statistically significant difference existed between two types of samples as well as values taken along and across the sandmarks of the HDF and overlaid panels. Average _Ra$R_{\mathrm{a}}$, _Rz$R_{\mathrm{z}}$, and _Rmax$R_{\max }$ values for HDF were found as 2.73, 26.04, and 27.27 μm, respectively. Overlaid samples resulted in 15.6%, 26.0%, and 21.0% lower values of above parameters than those of HDF panels.     

Some of the properties of wood–plastic composites

In this study some of the important properties of experimentally manufactured wood–plastic composites (WPC) were determined. Specimen having 60% and 80% particle and fiber of radiata pine (Pinus radiata ) were mixed with polypropylene (plastic) and four different additives, namely Structor TR 016 which is coupling agent, CIBA anti-microbial agent (IRGAGUARD F3510) as fungicide, CIBA UV filter coating (TINUVIN 123S), CIBA blue pigment (Irgalite), and their combinations. Based on the initial finding of this work static bending properties of the samples enhanced as above chemicals were added into both particle and fiber-based specimens. Thickness swelling of the samples were also improved with having additives in the panels. Micrographs taken on scanning electron microscope (SEM) revealed that coupling agent and pigment resulted in more homogeneous mixture of wood and plastic together. Two surface roughness parameters average roughness (R_a) and maximum roughness (R_max) used to evaluate surface characteristics of the samples showed that particle based samples had rougher surface characteristics than those of fiber based ones. No significant influence of chemicals added in the samples was found on surface roughness values of the samples manufactured from particle and fiber of radiata pine.     

Feasible method,utilizing density changes,for estimating in situ dynamic strength and deformation properties of sand samples

Laboratory tests and design reliability are directly controlled by sample quality. The frozen sampling (FS) method is useful for dynamic strength and deformation tests of undisturbed clean sand. However, it is very expensive and requires considerable equipment. The sample quality of Toyoura sands obtained from 48 mm and 75 mm samplers are scrutinized based on void ratio, dynamic strength and deformation properties through model and cyclic undrained triaxial tests. A conventional method for estimating in-situ dynamic strength and deformation properties of sand samples utilizing density changes is examined and the applicability of the proposed method is discussed for the samples obtained from Niigata sand deposits.The main conclusions obtained from this study are summarized as follows:(1) A conventional method for estimating in-situ void ratio (e₀), D_r, stress ratio (R_L20) in a 20 cyclic time frame and the initial modulus of rigidity (G₀) of sand samples utilizing density changes is proposed.(2) The in-situ R_L20 and G₀ estimated from the proposed method for sand samples from tube samplers were similar to those of frozen sampling and the in-situ modulus of initial rigidity was calculated from the secondary wave velocity for Niigata sand deposits.Therefore, dynamic strength and deformation properties changes, caused by sampling, can be modified appropriately to an in-situ condition by this proposed method.     

Comparison of surface roughness of Locust acacia (Robinia pseudoacacia L.) and European oak (Quercus petraea (Mattu.) Lieble.) in terms of the preparative process by planing

Effects of number of the cutters (planing knives), feed rate (operational speed) and cutting depth (biting thickness) on the surface roughness of Locust acacia (Robinia pseudoacacia L.) and European oak (Quercus petraea (Mattu.) Lieble.) were investigated on the base of the preparative differences by planing. The specimens were prepared by planing with two and four knives at 5 and 9 m/min feed rates in 1, 2 and 4 mm cutting depths. Surface roughness was measured from the radial face of each sample according to TS 930 (1989) by using Mitutoyo SJ-301 stylus scanner device. These measurements were performed perpendicular to the fibers by the sampling length of 12.5 mm at a sensitivity level of ±0.01 μm. Considering between all types of the experimental preparations, Locust acacia had the smoothest surfaces than that of European oak. Comparing the results of the surface roughness of both species, it has been obtained that the surface roughness decreases when the feed rate and the cutting depth decreases, whereas it increases when the knives on the cutter heads decreases. Therefore, it may be suggested that the perfect faces could be particularly prepared for this considered species by the greater number of the knives (four) at the slow feed rate (5 m/min) in the condition of the light cutting depth (1 mm).     

Deposition of aerosol particles on rough surfaces inside a test chamber

We investigated the deposition rate of aerosol particles (diameter between 0.03 and 5 μm) on rough surfaces of wallpapers, wall-plasters, and two types of carpets inside a test chamber. Compared to a smooth aluminum surface, the deposition rate of aerosol particles on the tested surfaces was up to 20 times depending on the surface roughness, mixing intensity, and particle size. A rough surface with a dimensionless surface roughness height k⁺ < 0.06 can be treated as a hydraulically smooth. The estimated deposition rates in this study and those predicted by a deposition model, which incorporates surface roughness, were in good agreement for coarse mode particles (diameter > 1 μm) when k⁺ < 1.04 and for ultrafine particles (diameter < 0.1 μm) when k⁺ < 0.48. The agreement between the model prediction and our estimation was better for coarse mode particles than for ultrafine particles. Deposition of aerosol particles, especially fine particles, needs more empirical investigations aiming at improving the existing models.     

Mapping of background air pollution at a fine spatial scale across the European Union

Background

There is a need to understand much more about the geographic variation of air pollutants. This requires the ability to extrapolate from monitoring stations to unsampled locations. The aim was to assess methods to develop accurate and high resolution maps of background air pollution across the EU.

Methods

We compared the validity of ordinary kriging, universal kriging and regression mapping in developing EU-wide maps of air pollution on a 1 × 1 km resolution. Predictions were made for the year 2001 for nitrogen dioxide (NO₂), fine particles < 10 µm (PM₁₀), ozone (O₃), sulphur dioxide (SO₂) and carbon monoxide (CO) using routine monitoring data in Airbase. Predictor variables from EU-wide databases were land use, road traffic, population density, meteorology, altitude, topography and distance to sea. Models were developed for the global, rural and urban scale separately. The best method to model concentrations was selected on the basis of predefined performance measures (R², Root Mean Square Error (RMSE)).

Results

For NO₂, PM₁₀ and O₃ universal kriging performed better than regression mapping and ordinary kriging. Validation of the final universal kriging estimates with results from all validation sites gave R²-values and RMSE-values of 0.61 and 6.73 µg/m³ for NO₂; 0.45 and 5.19 µg/m³ for PM₁₀; and 0.70 and 7.69 µg/m³ for O₃. For SO₂ and CO none of the three methods was able to provide a satisfactory prediction.

Conclusion

Reasonable prediction models were developed for NO₂, PM₁₀ and O₃ on an EU-wide scale. Our study illustrates that it is possible to develop detailed maps of background air pollution using EU-wide databases.     

Behavior of cantilever and geosynthetic-reinforced walls on deformable foundations

A series of plane-strain model tests was performed to investigate the behavior of cantilever soil retaining walls (CWs) and geosynthetic-reinforced soil retaining walls with a rigid facing (GRS-RWs) placed on non-deformable and deformable foundations with various subgrade reaction moduli (k_v). The walls were designed to have configurations similar to those used in practice, with similar controlling safety factors against sliding. Screw jacks and springs were used to simulate undeformable and deformable grounds, respectively, with various maximum foundation settlements of S_max ≒ 0, 2.5, 5, and 10% of the backfill height (H). Test results show that the GRS-RW has better settlement-tolerating performances, in terms of the tilting angle (θ), the horizontal displacement (D_h), and the settlement of the crest of the backfill (D_v1), than those of the CW. For both CWs and GRS-BWs, the worst scenario of the wall performance, in terms of D_h, θ and D_v1, occurred at a moderate foundation settlement of S_max/H ≒ 5% (or k_v = 1.8 kPa/mm), rather than at a greater foundation settlement of S_max/H ≒ 10%, which facilitates a tilting-backward displacement mode. Experimental results also indicate that local lateral pressure coefficients against facing (K_f,z) for CWs may reach the at-rest (or K_o) state at the central portion; values of K_f,z may reach the passive (or K_p) state at the lower portion of the wall. In the case of CWs, the measured values of local and global lateral pressure coefficients (K_f,z and K_f) tend to increase with increasing maximum foundation settlement. This is not the case for GRS-RWs, which exhibited a relatively settlement-independent response, in terms of K_f and K_f,z, against facing. To develop relevant limit-equilibrium-based design methods for CWs and GRS-RWs placed on deformable foundations, knowledge of lateral pressure coefficients associated with various displacement and tilting induced by the foundation settlement are required.     

Characterisation of atmospheric deposition as a source of contaminants in urban rainwater tanks

To characterise atmospheric input of chemical contaminants to urban rainwater tanks, bulk deposition (wet + dry deposition) was collected at sixteen sites in Brisbane, Queensland, Australia on a monthly basis during April 2007-March 2008 (N = 175). Water from rainwater tanks (22 sites, 26 tanks) was also sampled concurrently. The deposition/tank water was analysed for metals, soluble anions and selected samples were additionally analysed for PAHs, pesticides, phenols, organic & inorganic carbon. Flux (mg/m²/d) of total solids mass was found to correlate with average daily rainfall (R² = 0.49) indicating the dominance of the wet deposition contribution to total solids mass. On average 97% of the total mass of analysed components was accounted for by Cl⁻ (25.0%), Na (22.6%), organic carbon (20.5%), NO₃⁻ (10.5%), SO₄²⁻ (9.8%), inorganic carbon (5.7%), PO₄³⁻ (1.6%) and NO₂⁻ (1.5%). For other minor elements the average flux from highest to lowest was in the order of Fe > Al > Zn > Mn > Sr > Pb > Ba > Cu > Se. There was a significant effect of location on flux of K, Sb, Sn, Li, Mn, Fe, Cu, Zn, Ba, Pb and SO₄²⁻ but not other metals or anions. Overall the water quality resulting from the deposition (wet + dry) was good but 10.3%, 1.7% and 17.7% of samples had concentrations of Pb, Cd and Fe respectively greater than the Australian Drinking Water Guidelines (ADWG). This generally occurred in the drier months. In comparison 14.2% and 6.1% of tank samples had total Pb and Zn concentrations exceeding the guidelines. The cumulative mean concentration of lead in deposition was on average only 1/4 of that in tank water over the year at a site with high concentrations of Pb in tank water. This is an indication that deposition from the atmosphere is not the major contributor to high lead concentrations in urban rainwater tanks in a city with reasonable air quality, though it is still a significant portion.     

A parameterization of dust concentration (PM₁₀) of dust events observed at Erdene in Mongolia using the monitored tower data

Hourly mean time series of dust concentration (PM₁₀) measured at 3 m high and a sonic-anemometer measured momentum and kinematic heat fluxes at 8 m high above the surface have been obtained from a 20-m monitoring tower located at Erdene in the Asian dust source region of Mongolia for years of 2009 and 2010. These time series were used to identify dust events and to develop optimal regression equations for the dust concentration of dust events with the friction velocity (u_*) and the convective velocity scale (w_*). In total, 68 dust events were identified in 2009 (except for November) and 43 dust events for the period from March to August in 2010. The duration of each dust event ranged from 3-29 h in 2009 and 5-35 h in 2010. The maximum hourly mean dust concentration of the dust event was found to be 4,107 μg m^− 3 in May in 2009 and 4,708 μg m^− 3 in March in 2010 while a minimum of 251 μg m^− 3 in August in 2009 and 662 μg m^− 3 in June in 2010. The optimal regression equation for the dust concentration (C) of dust events was found to have the form of log C = a + b(u_* + cw_*)ⁿ, where a, b, c and n are constants that vary month to month. The convective velocity scale (w_*) that has not been taken into account in most dust modelings was found to enhance the dust concentration of dust events during the cold period from December to March when the soil temperature was below the freezing level for both the stable (w_* < 0) and unstable (w_* > 0) stratifications, whereas the convective velocity caused a reduction in the dust concentrations during the warm period from April to October, suggesting the importance of the convective velocity to estimate dust concentration of dust events.     

Experimental and DEM assessment of the stress-dependency of surface roughness effects on shear modulus

This contribution assesses the effect of particle surface roughness on the shear wave velocity (V_S) and the small-strain stiffness (G₀) of soils using both laboratory shear plate dynamic tests and discrete element method (DEM) analyses. Roughness is both controlled and quantified to develop a more comprehensive understanding than was achieved in prior contributions that involved binary comparisons of rough and smooth particles. Glass beads were tested to isolate surface roughness effects from other shape effects. V_S and G₀ were accurately determined using a new design configuration of piezo-ceramic shear plates. Both the experimental and the DEM results show that increasing surface roughness reduces G₀ particularly at low stress levels; however, the effect is less marked at high pressures. For the roughest particles, the Hertzian theory does not describe the contact behaviour even at high pressures; this contributes to the fact that the exponent in the G₀ – mean effective stress relationship exceeds 0.33 for sand particles. Particle-scale analyses show that the pressure-dependency of the surface roughness effects on G₀ can be interpreted using roughness index α which enables the extent of the reduction in G₀ due to surface roughness to be estimated.     

Assessment of rock fracture surface roughness using Riemannian statistics of linear profiles

The mechanical behaviour of rock masses is complex, due partly to the presence of discontinuities within them. Of the geometrical parameters of discontinuities, surface roughness, which encapsulates the topographical features of a rock surface, is known to play a significant role. Here, a new parameter for quantitative roughness determination based on the distribution of unit normal vectors to a rock profile is presented.The analysis of unit normal vectors in terms of directional statistics is customarily performed in Euclidean space using a Cartesian co-ordinate system. Here, the analysis is developed using Riemannian geometry, with Mahalanobis distances being proposed for discrimination between different rock profiles. Statistical parameters on the unit circle are extracted using Riemannian geometry, and from that a roughness parameter, D_R1, is obtained. This parameter corresponds to 1D Riemannian dispersion, and as such D_R1 increases as profile roughness increases.D_R1 is applied to the analysis of synthetic profiles and some real rock profiles. Conclusions are drawn that demonstrate the advantages of the new method in terms of investigating the scale effect in roughness determination as well as in comparing different profiles.A preliminary study into the correlation between D_R1 and the shear strength of a fracture, using analytical and numerical investigation of the strength of profiles comprising symmetric triangular asperities sheared at different normal stress levels, shows a clear relation between Riemannian roughness parameter and profile shear strength.