Comparative analysis of modern and ancient buried Phoebe zhennan wood:surface color,chemical components,infrared spectroscopy,and essential oil composition

We compared the chemical components and essential oils of ancient buried Zhennan（Phoebe zhennan）wood with those in samples from living trees.After removal of the carbon layer the recovered Zhennan exhibited a dark green color,which differed from the yellow color of the living samples.Low molecular weight components（including hot-water and toluene-alcohol extractives）,hemicellulose,and 1 % Na OH solubility in the recovered wood were greatly degraded.Degradation of cellulose was minor.Moreover,the ancient wood had somewhat more klason lignin than the modern wood.Fourier transform infrared（FTIR） analysis gave further evidence on the differences in chemical components.According to the GC–MS results,naphthalene derivatives were detected in the essential oils from both the modern and recovered wood.The delicate fragrance of the modern and recovered wood may be attributed to the aromatic constituents as identified by GC–MS.

Effects of characteristic inhomogeneity of bamboo culm nodes on mechanical properties of bamboo fiber reinforced composite

Dendrocalamus farinosus and Phyllostachys heterocycla bamboo logs were subjected to a novel treat- ment process for the preparation of bamboo fiber mats （BFMs）, and the obtained BFM were used to fabricate bamboo fiber reinforced composite （BFRC）. We studied the mechanical properties of the BFRCs manufactured from the mats with and without bamboo nodes. The pres- ence of nodes in BFM greatly reduced tensile strength, compressive strength, modulus of elasticity, and modulus of rupture of the BFRCs, while the BFRCs fabricated from BFMs with nodes possessed higher horizontal shear strength. Therefore, the nodes in bamboo culms were an important factor in the uniform distribution of mechanical properties, and BFMs should be homogeneously arranged to reduce the impact of nodes on the mechanical strengths of BFRCs.

Optimization for microwave-assisted direct liquefaction of bamboo residue in glycerol/methanol mixtures

Bamboo residues were liquefied in a mixture of glycerol and methanol in the presence of sulfuric acid using microwave energy. We investigated the effects of liquefaction conditions, including glycerol/methanol ratio, liquefaction temperature, and reaction time on the conversion yield. The optimal liquefaction conditions were under the temperature of 120 °C, the reaction time of 7 min, the glycerol–methanol–bamboo ratio of 8/0/2（W/W）, and the microwave power of 300 W. Maximum conversion yield was 96.7 %. The liquid products were separated into two contents（water soluble part and precipitate part） by addition of a sufficient amount of water. By Fourier transform infrared（FT-IR）, the water soluble content mainly contained glycerol and its derivate and carbohydrate degradation products, and the precipitate content was mainly lignin derivatives.

Preliminary evaluation of liquefaction behavior of Eucalyptus grandis bark in glycerol

Eucalyptus grandis W.Hill ex Maiden bark was liquefied in glycerol with two types of catalysts.The chemical components of the residues with respect to temperature were examined to investigate the liquefaction behavior of bark.The results reveal that sulfuric acid was more efficient in converting bark into fragments in glycerol at low temperatures B 433.15 K,equivalent to 160C than phosphoric acid.The liquefaction order of chemical components was lignin,hemicelluloses,and cellulose.The decrease of liquefaction yields at high temperatures(≤453.15 K)catalyzed by sulfuric acid was possibly a result of the recondensation of lignin and/or hemicelluloses.

Optimization of Extraction and Characterization of Pectin from Grapefruit Peels

In this study, pectin was extracted from grapefruit peels with hydrochloric acid and precipitated with 95% ethanol solution and 5% tartaric acid. The physical and chemical properties of pectin obtained were analyzed, including color, texture, degree of esterification, and water solubility. The effects of peel to sol- vent ratio, pH of the solvent, extraction temperature and extraction duration on pectin extraction rate were investigated. On the basis of single-factor experiments, an L9 （34） orthogonal experiment was performed to screen the optimal extraction conditions. According to the results, the optimal combination of technical parame- ters was A1B3 C1 D3, i. e. , solid to liquid ratio 1：40 （g： ml）, pH 2.0, extraction duration 70 rain, extraction temperature 90 ℃. The average pectin extraction rate was 68.60% ; the color of pectin extracted under the optimal conditions varied from milky white to light yellow; the degree of esterification of pectin extracts was 65. 71% ; the extracted pectin exhibited good water solubility. Key words Pomelo peel; Pectin extraction; Optimum conditions; Esterification degree; Water solubility

Effect of Fertilization on Anatomical and Physical-mechanical Properties of Neosinocalamus Affinis Bamboo

In order to maintain soil fertility of Neosinocalamus affinis plantations,fertilizers of N,P,and K were applied.The anatomical and physical-mechanical properties of N.affinis bamboo wood from different fertilization treatments were measured.The aim of this study was to elucidate the effect of fertilization practice on the properties of N.affinis bamboo wood.The results revealed that the fertilization of P and K resulted in a slight reduction in fiber length.The application of P,K,and low level(0.3 kg/clump)of N fertilizers had no significant effect on the fiber morphology,while high level(0.9 kg/clump)of N fertilizer contributed to short fibers.The specific gravity was significantly decreased by fertilization,while the volume shrinkage was increased.Since the effect of various fertilization treatments had different influence patterns on the properties of N.affinis,specific evaluations on the quality of the fertilized bamboo wood should be performed prior to its utilization.