Use of wax emulsions for improvement of wood durability and sorption properties

Waxes are used for treatment of wood surfaces for several decades predominately as surface treatments because they weakly penetrate into the wood. In order to overcome this issue, water emulsions were applied in the present experiment. Five water emulsions of various concentrations were used, namely montan wax, polyethylene, ethylene copolymer and oxidized polyethylene wax. Performance of wax treated beech (Fagus sylvatica) and Norway spruce (Picea abies) against white rot, brown rot and blue stain fungi was tested. In parallel, sorption properties of wax treated wood were determined. The treated specimens were more resistant to wood decay fungi. Polyethylene and oxidized polyethylene wax were found to be particularly efficient. Although this treatment does not improve resistance to blue stain fungi, it reduces the sorption of water.     

Finite element simulations of the loading and deformation of plywood seat shells

Modern 3D modelling software reduces the need for a large number of prototypes, means fewer product-development cycles and lower costs (time/cost), as well as improving the quality of furniture designs. However, the mechanical testing of final products is still required in order to confirm the simulation results. In this study the theoretical behaviors of different plywood seating shells (using the SolidWorks^® FEM simulation software) were compared with the real results obtained using tests to measure the deformation of the backrest. The deviations of the actual deformation from the simulation were significant for the different shells and increased with loading above the elastic deformation limit of the material. It was concluded that the SolidWorks^® simulation software could be effectively used in the calculation of the component displacements, strains, and stresses of seat designs subject to internal and external loads.     

Tensile behavior of staple fiber yarns part III: comparison of mathematical models

Despite the development of artificial neural network and computer simulation models that predict yarn tensile properties, the mathematical model is still very important being the base for all models. In this research, three mathematical models have been applied for evaluation of coefficient of fiber strength utilization in staple spun yarns before break at same value of yarn strains. The experiments were conducted on cotton, viscose and polyester fibers, and yarns. The results indicated that our model exhibited least prediction error followed by Pan’s and Frydrych’s models for cotton and viscose but for polyester, Pan’s model produced least error followed by Frydrych’s model and our model. The superiority of our model might be resulted from the introduction of the phenomena of fiber directional distribution in the staple spun yarns.     

Effect of polymer concentration on electrospinning of hydroxypropyl-β-cyclodextrins/PEO nanofibres

Hydroxypropyl-β-cyclodextrin (HP-β-CD) is a β-cyclodextrin (β-CD) derivative which is toxicologically harmless to mammals and other animals. In this study, HP-β-CD is electrospun from an aqueous solution by blending with poly(ethylene oxide) (PEO). The aqueous solutions containing different HP-β-CD/PEO blends (50:50–90:10) with varying concentrations (4–12 wt.%) were electrospun at 1 ml/h feed rate, 12 cm working distance and 7 kV applied voltage. The morphology of the nanofibres was investigated by scanning electron microscope. The average diameter of the nanofibres was measured using ImageJ software. It was found from the results that the uniform nanofibres with an average diameter of 264, 244 and 236 nm were obtained from 8 wt.% solution of 50:50, 60:40 and 70:30 HP-β-CD/PEO blends, respectively. The average diameter of the fibre decreases with increasing HP-β-CD/PEO ratio. However, higher proportion of HP-β-CD (i.e. above 70:30 HP-β-CD/PEO blend) in the spinning solution increases the possibility of creating more beads in the fibres. Although the polymer concentrations have not shown a significant effect on fibre diameter, the 8 wt.% solution of 50:50 HP-β-CD/PEO yielded uniform smooth fibres with the narrowest distribution of the diameters. As the aim of this study is to maximize the HP-β-CD content in the fibre, the blend ratio of 70:30 HP-β-CD/PEO and solution concentration of 8 wt.% were optimized to obtain smooth HP-β-CD/PEO nanofibres.     

The influence of material properties on the amount of twist of spruce wood during kiln drying

The development of twist in Norway spruce boards (Picea abies Karst.) during normal temperature kiln drying was researched. Tangentially oriented boards were sawn from diametrical radial planks, from which the basic wood properties, i.e. linear shrinkage and grain angle, were determined. The unrestrained boards were kiln dried using a selected drying schedule. During the controlled drying process the moisture content (MC) and twist of the boards were measured. Twist was generally induced by the shrinkage of wood below the fibre saturation point, and increased in proportional to the decrease in MC. The earlier appearance of twist, with regard to MC and drying time, was confirmed in the case of boards sawn from the central part of logs. The final twist amounted to between 10 and 20°/m in the case of boards close to the pith, and decreased to less than 4°/m in the case of boards sawn at a radius of 70 mm from the centre of the logs. Ring curvature had the highest impact on the final twist of the dried boards, followed by grain angle and tangential shrinkage.     

Characterization of a formaldehyde-free cornstarch-tannin wood adhesive for interior plywood

This study investigated the physical properties (rheological and thermogravimetric analysis) of cornstarch-tannin adhesives and the mechanical properties (dry tensile strength and 3-point bending strength) of plywood made using cornstarch-tannin adhesives. This adhesive was evaluated for its utility in interior plywood manufacture. The optimum cure temperature and cure time of cornstarch-tannin adhesives were 170°C and 4?min, respectively. Plywood bonded with formaldehyde-free cornstarch-tannin adhesive exhibited excellent mechanical properties comparable to commercially available phenol-formaldehyde plywood adhesives. It was found that cornstarch-tannin panels which do not contain formaldehyde and with an emission equal to that of heated but unbound wood can be obtained by the use of hexamethylenetetramine (hexamine) as hardener. The work has indicated that an environmentally friendly wood adhesive can be prepared from a natural renewable resource (cornstarch and wattle tannin) for bonding interior-type plywood.     

宁夏不同品种藜麦中维生素B 1 和维生素B 2 含量分析

藜麦样品经酶解处理后,应用高效液相色谱分析仪对不同品种中维生素B_1和维生素B_2的含量进行测定分析,结果表明,每个供试样品中都含有维生素B_1和维生素B_2,维生素B_1平均含量为0.183 mg/100 g,维生素B_2平均含量为0.077 mg/100 g,此研究为藜麦营养价值的评价提供参考依据。     

Effect of oil heating age on colour and dimensional stability of heat treated Pinus radiata

Pinus radiata specimens with moisture content of 8–11% and dimensions of 90×35×200 mm³ were heat-treated in an oil bath of commercial grade raw linseed oil. The effect of oil aging was investigated under treatment condition of 180°C and 3 hours by using oil that had been preheated for 0, 3, 9, 15, 21, and 27 hours, respectively, before the wood treatment. After treatment using oils of varying ages, wood colour change was examined using a Minolta spectrophotometer through CIE 1976 (L ^* a ^* b) system. Water repellent efficiency and anti swelling efficiency in high humidity conditions were measured to determine the stability of the treated wood. The results show that stability of the treated wood was improved significantly compared to the matched untreated wood but the treated wood tended to be darker. Oil viscosity increased with the heating age resulting in slight decrease in weight percentage gain. Water repellent efficiency was decreased with an increase in heating age of oil. However no significant difference in total colour variation and wood stability (anti swelling efficiency) was observed between specimens treated with oils of varying heating age.     

Mechanical properties of double-layered woven fabrics used in car seat upholstery

The objective of this study is to examine mechanical performance of double-layered woven fabrics used in car seat upholstery. For this purpose, 450 denier polyester yarns were supplied to produce double-layered woven fabrics. For the production of the fabrics, full weft connection, which is warp yarn of the top layer makes a connection with the weft yarn of the bottom layer, was used. To produce such a fabric, four different factors such as bottom layer pattern, number of interlacing warps in a unit report, number of interlacing picks per top warp and number of weft skips were investigated using Taguchi experimental design. After weaving stage, fabrics were stentered. Mechanical and physical properties of the fabrics were measured before and after stentering and the results were analysed with regard to Taguchi experimental analysis.     

Determination of correction coefficient for dynamic modulus of elasticity obtained by analysing the frequency response of a clamped cantilever specimen

In most cases, the analyses and calculations performed by numerous authors dealing with the dynamic methods of determining the modulus of elasticity E were based on cases where the requirements resulting from the boundary conditions of analytical solutions were met in full. However, in the case of cantilever clamping, there is a problem of how to realize the rigid clamping boundary conditions requiring zero flexure and the incline of the specimen in the clamping region. When calculating a dynamic module, it is therefore necessary either to take into account – in the case of low clamping ratios – a correction factor depending on the test sample, or to clamp the test sample so as to provide for a greater ratio of the sample free length to thickness. In our case, the error in calculating the modulus of elasticity decreases from 20% at the clamping ratio of 18 to just 5% at the clamping ratio of about 100.     

Validation of a lateral flow test (MRLAFMQ) for the detection of aflatoxin M1 at 50 ng l−1 in raw commingled milk

Aflatoxin M₁ contamination in dairy products is a risk when feedstuff contaminated with aflatoxin B₁ produced by moulds is consumed by milk-producing animals. Milk can be screened for aflatoxin M₁ at the European Union maximum limit of 50 ng l^?1 by a lateral flow test, the MRLAFMQ (Aflatoxin M1) Test. The method takes 15 min with no milk dilution or a sample preparation step. The lateral flow assay was validated at the Technology and Food Science Unit of the Institute for Agricultural and Fisheries Research (ILVO-T&V) according to European Union guidelines using fortified raw milk samples. A detection capability of 50 ng l^?1 was demonstrated with a false negative rate lower than 2% at 50 ng l^?1 and a false positive rate of less than 0.3%. Quantitative readings had a mean bias of +2 to 6 ng l^?1 at 50 ng l^?1 with a standard deviation of 5–8 ng l^?1. Based on the validation results, the test could be considered appropriate for milk screening prior to milk unload at dairies.     

Development and optimization of a new formaldehyde-free cornstarch and tannin wood adhesive

The development and optimization of a new, environment-friendly adhesive made from abundant and renewable cornstarch and tannin is described in this study. At present, the production of wood composites mainly relies on petrochemical- and formaldehyde-based adhesives such as phenol-formaldehyde (PF) resins and urea-formaldehyde (UF) resins. Formaldehyde-free cornstarch plus tannin adhesives were evaluated for mechanical and physical properties (shear strength, rheological characterisation and thermogravimetric analysis). First, optimized conditions for the preparation of cornstarch-sodium hydroxide wood adhesives were determined. The parameters studied were the following: total solids content of the adhesives, sodium hydroxide concentration and sodium hydroxide/cornstarch volume ratio. The highest shear strength results appeared to be 0.5 sodium hydroxide/cornstarch volume ratio when using concentrations of cornstarch (65% p/v H₂O) and sodium hydroxide (33% p/v H₂O). The optimum cure temperature was 170 °C and the cure time 4 min. The addition of two types of tannin-based adhesives, Mimosa and Quebracho, with hexamethylenetetramine (hexamine) hardener to the cornstarch-sodium hydroxide formulation improved the shear strength and decreased the viscosity of adhesives.     

Microwave testing of moist and oven-dry wood to evaluate grain angle,density, moisture content and the dielectric constant of spruce from 8 GHz to 12 GHz

The scope of this work is to discuss the challenges and demonstrate the potential of microwave testing for applications in the wood processing industry. Microwave technology benefits from the anisotropic dielectric properties of wood to simultaneously identify grain angle, density, and moisture content of wood. Therefore, the theory of free space transmission measurement is thoroughly discussed with emphasis on the characteristics of (and how to deal with) reflections occurring in real measurements. A more sophisticated calculation method for the derivation of the desired physical wood properties is presented. The advantages of a modern laboratory style setup are shown and its possible transition in an industrial-style application is discussed. Moist (moisture content 7.6–14%) and oven-dry spruce samples are tested. The detection of grain angle for moist and oven-dry wood yields an RMSE (root-mean-squared-error) of 0.14° and 0.4°, respectively. Moisture content is evaluated with density- and thickness-independent methods. Adapted regression models are proposed yielding an RMSE for moisture content of 0.45% for a single frequency measurement. The promising advantages of wood moisture estimation with frequency sweeps instead of fixed frequency signals are discussed and demonstrated for all samples (RMSE 0.39%). The dielectric constant of moist and oven dry spruce in the range from 8 to 12 GHz is evaluated in respect to density, moisture content and temperature. The respective constants ε′, ε′′, and tan(δ) are formulated in a general form via a non-linear regression and compared to existing data in literature.     

Bulk Optical Properties of Potato Flesh in the 500–1900 nm Range

In this study, the optical properties of potato flesh tissue were estimated using double-integrating sphere (DIS) measurements combined with an inverse adding-doubling (IAD) light propagation model. Total reflectance, total transmittance, and unscattered transmittance were measured for the wavelength range 500–1900 nm with 5-nm resolution. From these measurements, the bulk optical properties (absorption coefficient, scattering coefficient, and anisotropy factor) of 53 potato tubers of the Hermes cultivar were estimated. The estimated absorption coefficient spectra were dominated by water and starch absorption bands, the main chemical components of potato tissue. Comparison of these values to those reported in literature for similar products showed comparable absorption profiles. The obtained scattering coefficient spectra showed a smooth decrease from 166 to 160 cm^?1 in the near-infrared (NIR) spectral range with increasing wavelength, which is common for biological tissues. The anisotropy factor spectra obtained for the full wavelength range studied ranged between 0.949 and 0.959 with a maximum variability of 0.009 among the set of samples used. The information obtained in this study is essential to understand the effects of absorption and scattering on the propagation of light through the potato tubers in order to design more efficient sensors for non-destructive quality evaluation.     

Determination of meat pH - temperature relationship using ISFET and glass electrode instruments

pH measurements of beef, pork and lamb were made over the range 0-35°C in order to establish the dependence of pH on temperature (ΔpH/ΔT). Measurements were made using a newly developed ISFET pH probe and a conventional glass probe. The results indicated values of ΔpH/ΔT in the range of -0.006 to -0.007 pH units/°C, and are compared to the few other values of ΔpH/ΔT reported for meat and to values generally reported in physiological studies of animal tissue. It is suggested that in meat studies and in industrial monitoring of pH, greater attention be given to potential sources of error that can arise from unrecognised temperature-related pH effects. It is also suggested that consideration be given by the industry to establishing an agreed temperature at which meat pH is reported so that valid comparisons of different pH measurements may be made.     

Use of a highly sensitive latex reagent with amino acid spacer for determination of C-reactive protein concentration in a variety of liver diseases

C-reactive protein (CRP) is a major acute-phase protein, which is extremely important in inflammatory disease diagnosis. CRP is rapidly elevated in various diseases as a result of tissue injury, infection and inflammation. Recently, many reports have shown its usefulness as a risk marker for arteriosclerosis and metabolic syndrome. However, the lack of sensitivity of existing CRP assays has hampered CRP testing in conditions associated with viral infections, where CRP levels typically elevate only marginally. In this report, we prepared a novel, ultra-sensitive latex-based CRP test using amino acid spacers with a high sensitivity and a wider assay range. Our method of conjugating latex beads enabled us to measure CRP in the range of 5-500?ng/mL in patient sera. Furthermore, we studied CRP levels in patients with various liver diseases, such as chronic hepatitis, liver cirrhosis and hepatic carcinoma, in order to examine the correlation between severity of liver dysfunction and CRP levels, and to examine the likelihood of recurrence of liver dysfunction. The reagent was simple to prepare and sensitive during clinical investigation, where it discriminated clearly between normal subjects and those with liver diseases. Therefore, we conclude that our ultra-sensitive CRP assay will contribute greatly to the clinical study of hepatic disorders.     

Biological properties of an OSB eco-product manufactured from a mixture of durable and non durable species and natural resins

OSB panels were manufactured with a mixture of pine and cypress heartwood and lignin and tannin based resins in order to propose an eco-friendly wood composite. The resistance of OSB panels against Reticulitermes santonensis was tested according to EN 118 and EN 117 as well as in a field test. OSB made from cypress showed more resistance against the tested termite, the resistance decreased as the percentage of pine increased. The degree of attack differed according to the choice of standard procedure. The field test results revealed that in outdoor conditions and when the termites had a feeding choice, all mixtures showed the same behaviour. The decay resistance was assessed according to EN 12038, and the results revealed that the resistance increases when the percentage of cypress increases.     

Identification of yeast and acetic acid bacteria isolated from the fermentation and acetification of persimmon (Diospyros kaki)

Persimmon (Diospyros kaki) is a seasonal fruit with important health benefits. In this study, persimmon use in wine and condiment production was investigated using molecular methods to identify the yeast and acetic acid bacteria (AAB) isolated from the alcoholic fermentation and acetification of the fruit. Alcoholic fermentation was allowed to occur either spontaneously, or by inoculation with a commercial Saccharomyces cerevisiae wine strain, while acetification was always spontaneous; all these processes were performed in triplicates. Non-Saccharomyces yeast species were particularly abundant during the initial and mid-alcoholic fermentation stages, but S. cerevisiae became dominant toward the end of these processes. During spontaneous fermentation, S. cerevisiae Sc1 was the predominant strain isolated throughout, while the commercial strain of S. cerevisiae was the most common strain isolated from the inoculated fermentations. The main non-Saccharomyces strains isolated included Pichia guilliermondii, Hanseniaspora uvarum, Zygosaccharomyces florentinus and Cryptococcus sp. A distinct succession of AAB was observed during the acetification process. Acetobacter malorun was abundant during the initial and mid-stages, while Gluconacetobacter saccharivorans was the main species during the final stages of these acetifications. Four additional AAB species, Acetobacter pasteurianus, Acetobacter syzygii, Gluconacetobacter intermedius and Gluconacetobacter europaeus, were also detected. We observed 28 different AAB genotypes, though only 6 of these were present in high numbers (between 25%–60%), resulting in a high biodiversity index.     

Properties of oriented strandboard made of wood species from Brazilian planted forests: Part 1: 80 mm-long strands of Pinus taeda L.

This research is part of a general study on the properties of oriented strandboard (OSB) using wood strands of species from Brazilian planted forests. The OSB industry is the latest wood related activity established in Brazil. In this particular part of the study, 80 mm long strands of Pinus taeda L. were bonded using two resin types (urea-formaldehyde and phenol-formaldehyde) at two levels of resin content (5% and 8%) to produce three-layer cross-aligned OSB to a face to core layer ratio of 1:2 and target density of 0.75 g/cm³. Physical and mechanical properties of the boards were evaluated according to ASTM standard D 1037-96a (1997) and the results compared to standards available as requirements for commercial structural panels. The results indicate that all the mechanical properties evaluated were above the requirements set forth by the Canadian standard CSA O437.0 (1993) for structural panels. The results of Janka hardness were in average 4 folds higher than the minimal requirements for Grade R-1 waferboard. Screw withdrawal values were also above the minimum required by grade M-3 of ANSI A208.1 standard (1993). Nevertheless, values of thickness swelling and water absorption were very high. The low dimensional stability may be related to the high density of the boards (“springback” effect) and also to the fact that no wax was used.