Mechanization techniques for poplar development in Turkey

Annual commercial poplar wood production in Turkey is about 3.6 million cubic meters, half of which comes from hybrid poplar I-214. The poplar plantation areas of Turkey are 70% of the poplar plantation areas of the Near and Middle Eastern countries, and nearly 5% of the world. In this study, unit times of standard operations were investigated in poplar nurseries and plantations in which new mechanical technology was applied and compared with traditional methods. Analyses of unit times were made on 11 treatments for poplar nurseries and nine treatments for poplar plantations; some new methods are also recommended. Mechanization methods based on new technologies give promising results in poplar nurseries and plantations.     

Inversion of a radiative transfer model with hyperspectral observations for LAI mapping in poplar plantations

The potential of radiative transfer modelling and inversion techniques for operational uses is investigated in order to retrieve leaf area index in a poplar plantation. The 1-D bidirectional canopy reflectance model SAIL, coupled with the leaf optical properties model PROSPECT, was inverted with hyperspectral airborne DAIS data by means of an iterative method. The root mean square error in LAI estimation was determined against in situ measurements in order to evaluate the impact of different inversion strategies on the LAI retrieval accuracy. These included the selection of an optimal spectral sampling set, the exploitation of prior knowledge in the inversion process and the use of multiview angle data. We claim that the best configuration is achieved by exploiting multiview DAIS data and prior knowledge information about the model variables (RMSE of 0.39 m² m⁻²). It is also shown that the use of prior knowledge and the selection of a limited number of bands forming the optimal spectral sampling are instrumental in increasing the accuracy of the inversion process. Our analysis confirms the operational potential of model inversion for biophysical parameter retrieval.     

Anatomical characteristics,microfibril angle and micromechanical properties of cottonwood (Populus deltoides) and its hybrids

Samples were prepared using stem xylem from cottonwood (Populus deltoides) and two cottonwood hybrids (P. deltoides × Populus maximowiczii and P. deltoides × Populus trichocarpa), which grew in Tennessee, United States. The anatomical characteristics, microfibril angle, and mechanical properties of the cell wall in juvenile wood (two-year-old) were investigated by means of microscopy image analysis system, X-ray diffraction, and nanoindentation (NI). The results showed that the double-wall thickness of the fiber cells in the hybrid poplars was thicker than that of the pure poplar, and the ratio of wall to lumen of fiber cell (0.40) of the P. deltoides × P. trichocarpa, which had the slowest growth rate, reached the greatest value among the three poplar clones. Their microfibril angles (MFA) of the cell wall in the investigated samples ranged between 11.5° and 16.7°, and they correlated positively with growth rates of the three poplar clones. The average hardness and reduced elastic modulus were 0.25 GPa and 8.58 GPa for P. deltoides, 0.28 GPa and 8.34 GPa for P. deltoides × P. maximowiczii, and 0.31 GPa and 12.2 GPa for P. deltoides × P. trichocarpa, respectively. P. deltoides × P. trichocarpa with the slowest growth rate had the greatest micromechanical values among the three poplar clones. In combination with growth characteristics of the three poplar clones, the findings of the analyses on their wood properties provided information-rich data that not only could describe juvenile wood properties but also could be used in selective breeding for the three poplar clones in Tennessee, USA.     

Influence of the agricultural management practices on the yield and quality of poplar biomass (a 9-year study)

The aim of this work is to study the effect of different agricultural management on the yield and quality of two poplar biomass clones (AF2 and I-214 clones) in short rotation coppices (SRC), which were harvested using different alternatives (with and without cutting and sprouting after the first year), with two fertilisation doses and through three different 3-year rotation cycles. The plantation was established in 2006 in a marginal land at 1100 m above sea level in central-northern Spain. Yields were evaluated and biomass samples were analysed to determine the quality of the biomass for energy purposes. Biomass quality was estimated taking into account calorific value, volatile matter, ash content, carbon, nitrogen, sulphur and chlorine contents, as well as the chemical composition and melting behaviour of their ashes.The highest yields, around 9 dry tons per hectare and year, were obtained in this marginal land during the first and second rotation cycles when plots received a supplementary fertilisation. Both clones (AF2 and I-214) provided similar yield and biomass quality. Plots where poplar was not harvested the first year (without cutting and sprouting after the first year) provided higher accumulated yields. Poplar biomass from SRC can be considered a suitable solid biofuel due to its appropriate ash melting behaviour and its low content of nitrogen (0.44 wt-%), sulphur (0.03 wt-%) and chlorine (around 0.01 wt-%). No important significance effect on the poplar quality can be found depending on the additional fertilisation. Poplar quality varied as a function of root/stem age.     

Mathematical Modeling the Drying of Poplar Wood Particles in a Closed-Loop Triple Pass Rotary Dryer

Closed-loop drying systems are an attractive alternative to conventional drying systems because they provide a wide range of potential advantages. Consequently, type of drying process is attracting increased interest. Rotary drying of wood particles can be assumed as an incorporated process involving fluid–solid interactions and simultaneous heat and mass transfer within and between the particles. Understanding these mechanisms during rotary drying processes may result in determination of the optimum drying parameters and improved dryer design. In this study, due to the complexity and nonlinearity of the momentum, heat, and mass transfer equations, a computerized mathematical model of a closed-loop triple-pass concurrent rotary dryer was developed to simulate the drying behavior of poplar wood particles within the dryer drums. Wood particle moisture content and temperature, drying air temperature, and drying air humidity ratio along the drums lengths can be simulated using this model. The model presented in this work has been shown to successfully predict the steady-state behavior of a concurrent rotary dryer and can be used to analyze the effects of various drying process parameters on the performance of the closed-loop triple-pass rotary dryer to determine the optimum drying parameters. The model was also used to simulate the performance of industrial closed-loop rotary dryers under various operating conditions.     

BFRP加固新疆杨木柱的抗压试验研究

本文通过14根矩形截面新疆杨木柱的抗压试验,主要研究了BFRP的粘贴层数(一层、两层)和粘贴方式(满贴和间隔贴)对木柱极限承载力、纵向位移和横向挠度等性能指标的影响。结果表明:对新疆杨木柱进行BFRP加固可以提高木柱的极限承载力和纵向延性,其中承载力提高幅度12.1%~94.3%。     

HSQC (heteronuclear single quantum coherence) C-H correlation spectra of whole biomass in perdeuterated pyridinium chloride-DMSO system: An effective tool for evaluating pretreatment

Perdeuterated pyridinium chloride-DMSO-d₆ is an effective solvent system for whole cell biomass dissolution and NMR characterization. Employing this solvent system, semi-quantitative ¹³C-¹H heteronuclear single quantum correlation (HSQC) spectroscopy of untreated, steam, dilute acid and lime pretreated poplar biomass samples was readily accomplished. In an effort to demonstrate the efficacy and usefulness of this fairly new characterization technique, relative spectral intensities of the untreated and pretreated biomass samples were evaluated and compared. From the relative signal intensities of hemicelluloses in each system it was observed that hemicelluloses are being removed in various pretreatment conditions, but complete dissolution of hemicellulose was observed only with acid pretreatment. The relative changes in lignin subunits after pretreatment were estimated from the volume integration of resolved cross peaks of various lignin subunits. The degradation of lignin was observed in all pretreatments, though more significant changes were noticed after dilute acid and lime pretreatment. HSQC analysis results were in agreement with the composition analysis of pretreated biomass samples. Thus, this methodology broadens the application of whole cell NMR analysis in biofuel research.     

Development and validation of HPLC method for determination of salicin in poplar buds: Application for screening of counterfeit propolis

The main plant origins of propolis are the populus species and their hybrids, both located in China. Poplar tree gum, the extract of populus buds, has been widely used as counterfeit propolis, but no efficient method was known for detecting the counterfeit. Salicin is a characteristic marker of the genus populus, which may be hydrolysed by β-glucosidase during propolis collection and processing. A simple, sensitive and specific reversed-phase high-performance liquid chromatography (RP-HPLC) method was developed and validated for the rapid assay of salicin, which was aimed at distinguishing poplar tree gum from propolis. Isocratic elution at a flow rate of 1.0 mL/min was employed on a Sepax HP-C18 column (150 × 4.6 mm, 5 μm) and the column temperature was 30 °C. The mobile phase consisted of acetonitrile and 0.5% aqueous phosphoric acid (5:95, v/v). The UV detection wavelength was 213 nm. Following this method, salicin was detected in populus buds and leaves and 11 poplar tree gum samples, but not in any of the 40 propolis samples, which indicates that salicin was hydrolysed in propolis collection and processing but was stable in the production process of poplar tree gum. The proposed method could be an effective technique for routine analysis of salicin and monitoring the quality of propolis as possible counterfeit poplar tree gum.     

杨树绒毛纤维的性能及其采集应用

探讨杨树绒毛纤维的性能及其采集应用情况。介绍了杨树绒毛纤维的吸湿性能、浸润性能、蓬松性、热学性能和耐洗涤性能以及在纺织中的开发及应用情况。通过对杨树绒毛纤维的采集实践对比,认为:采集穗状花序,且采用晾晒制得杨树绒毛纤维,其杂质较少,便于控制采集的质量和数量。     

脲醛胶杨木/麦秸复合刨花板的工艺研究

采用正交试验的方法,研究了施胶量、热压温度、热压时间、杨木/麦秸刨花质量比例等工艺因素对脲醛胶杨木/麦秸复合刨花板的静曲强度、弹性模量、内结合强度、吸水厚度膨胀率等性能的影响。结果表明：采用杨木和麦秸为原料制造脲醛胶杨木/麦秸复合刨花板是可行的,其优化工艺参数为施胶量14%、单位热压时间40s/mm、热压温度180℃,杨木/麦秸刨花质量比例7/3。