The effect of sectioning and ultrasonication on the mesoporosity of poplar tension wood     

Shan-Shan?ChangEmail author  Fran?oise?Quignard  Bruno?Clair 《Wood Science and Technology》2017,51(3):507-516

Increasing interest in understanding tension stress generation in tension wood with fibres having a gelatinous layer (G-layer) has focused attention on the specific role of this layer. To distinguish its contribution from those of other wall layers, the G-layer of wood sections was isolated by ultrasonication. The aim of this study was to assess the effect of sectioning and of the ultrasonic treatment on the mesoporosity of tension wood using nitrogen adsorption–desorption analysis. The results showed that the process of isolating the G-layer using ultrasonication strongly affects its mesoporosity. Most damage was found to occur during sectioning rather than as a result of the 15-min ultrasonic treatment.  相似文献   

Synergistic effect of melamine polyphosphate and aluminum hypophosphite on mechanical properties and flame retardancy of HDPE/wood flour composites     

Liping?Li  Wei?Guo  Chuigen?GuoEmail author 《Wood Science and Technology》2017,51(3):493-506

In this paper, the influence of melamine polyphosphate (MPP) and aluminum hypophosphite (AHP) on mechanical properties, flame retardancy and thermal degradation of high-density polyethylene/wood flour composites (HDPE/WF) was investigated. The synergistic effect of MPP and AHP was investigated. Polyethylene grafted with maleic anhydride (PE-g-MAH) was used as coupling agent. The experimental data demonstrated that the HDPE/WF composites with 35 wt% MPP/AHP (3:2) could achieve a LOI value of 29.6 % and UL-94 V-0 rating. In addition, the cone value also revealed that the heat release rate and the smoke production rate were clearly reduced. SEM results showed that the synergistic system (MPP/AHP = 3:2) could form a dense and thick char layer and good adhesion between wood flour and HDPE matrix, which prevented the transfer of heat flux and fuel gases. Incorporation of MPP and AHP improved the thermal stability of HDPE/wood flour as observed from the thermogravimetric analysis results and also enhanced the thermal resistance of char layer at high temperature based on scanning electron microscopy observation.  相似文献   

Some geochemical features of soils formed under conditions of abandoned mercury deposits in Krasnodar Krai     

V.?A.?AlekseenkoEmail author  A.?V.?Alekseenko  L.?G.?Bogatyrev  N.?V.?Shvydkaya  A.?I.?Benediktova 《Moscow University Soil Science Bulletin》2017,72(2):84-91

Geochemical features of soils formed under conditions of abandoned cinnabar deposits in the Northwest Caucasus were studied for the first time. It was shown that the predominant elements in them are represented by titanium and manganese in the group of lithophilic elements, nickel and cobalt among siderophilic elements, and zinc and copper among chalcophilic elements. Similar regularities were revealed for the ash composition of tree species. Despite the fact that the modern soil cover is formed on various features of mesotopography, the content of elements is slightly contrasting.  相似文献   

Biological P cycling is influenced by the form of P fertilizer in an Oxisol     

Andrew?J.?MargenotEmail author  Rolf?Sommer  John?Mukalama  Sanjai?J.?Parikh 《Biology and Fertility of Soils》2017,53(8):899-909

Phosphate rock (PR) is an alternative fertilizer to increase the P content of P-deficient weathered soils. We evaluated the effects of fertilizer form on indicators of biological cycling of P using an on-farm trial on a Rhodic Kandiudox in western Kenya. Treatment plots were sampled after 13 cropping seasons of P applications as Minjingu phosphate rock (PR) or as triple super phosphate (?TSP) (50 kg P ha^?1 season^?1), as well as a P-unfertilized control (0 kg P ha^?1 season^?1). Soils (0–15 and 15–30 cm) were analyzed for microbial biomass P (P_mic), activities of acid phosphomonoesterase, alkaline phosphomonoesterase, and phosphodiesterase, and sequentially extractable P fractions. P additions as Minjingu PR yielded 299% greater P_mic than TSP at 0–15-cm depth despite similar labile P concentrations in the two P fertilization treatments and stimulated activities of acid phosphomonoesterase (+39%). When added in the soluble form of TSP, a greater percentage of total soil P was present in mineral-bound forms (+33% Fe- and Al-associated P). Higher soil pH under Minjingu PR (pH 5.35) versus TSP (pH 5.02) and the P-unfertilized treatment (pH 4.69) at 0–15-cm depth reflected a liming effect of Minjingu PR. The form of P fertilizer can influence biological P cycling in weathered soils, potentially improving P availability under Minjingu PR relative to TSP via enhanced microbial biomass P and enzymatic drivers of P cycling.  相似文献   

Long-term changes in land use impact the accumulation of microbial residues in the particle-size fractions of a Mollisol     

Xueli?Ding  Yunfa?Qiao  Timothy?Filley  Haiying?Wang  Xinxin?Lü  Bin?ZhangEmail author  Jingkuan?WangEmail author 《Biology and Fertility of Soils》2017,53(3):281-286

To test the impact of a range of long-term land use types on the partitioning of microbial residues among soil particles, samples from a Mollisol with plots under 100 years of continuous arable cropping, 30 years of simulated overgrazing to severely degraded bare soil, or 30 years of grassland restoration were investigated. The microbial residues, which were assessed among three particle-size fractions (<2, 2–20, and 20–250 μm) by amino sugar extraction, exhibited change with particle size and land use. Converting arable cropping to bare soil induced substantial depletion of amino sugars associated with the clay-size fraction, as a proportion of total carbon (C) and total soil mass, but not the silt- and sand-size fractions. Alternatively, switching arable soil to grassland increased amino sugar stocks in both the clay- and sand-size fractions. Analysis of the relative input of fungal and bacterial derived amino sugars indicated that fungal sources are the most dynamic with respect to land use change. These results highlight the selective vulnerability of microbial C pools in finer fractions under low plant C input and the selective recovery in specific fractions upon restoration, emphasizing the importance of the conversion of plant organic matter into mineral-associated microbial residues to promote stable soil organic C.  相似文献   

Improvement of paddy field drainage for mechanization   总被引：1，自引：1，他引：1  

Toshio?TabuchiEmail author 《Paddy and Water Environment》2004,2(1):5-10

In Japan, land consolidation and drainage improvement for farm mechanization in paddy fields began during the 1960 s. It was not easy to use big machines in the muddy conditions caused by the clayey soil and heavy rainfall during the harvesting period. A number of investigations were carried out by many researchers, and factors relating to drainage were clarified. Not only surface drainage but also underdrainage was planned. However, drainage was not always sufficient, because the clayey surface soil was impermeable to ponding water. It became clear that underdrainage for a clayey paddy field for the harvest is quite different from underdrainage for an ordinary field. Field and soil characteristics, as well as water conditions, should be examined carefully before planning drainage improvement for farm mechanization.Dr. Toshio Tabuchi is an honorable member of the Japanese Society of Irrigation, Drainage and Reclamation Engineering (JSIDRE), a former Professor of the University of Tokyo, and a former President of JSIDRE  相似文献   

Nutritional Evaluation of Wheat–Fenugreek Blends for Product Making     

Hooda S  Jood S 《Plant foods for human nutrition (Dordrecht, Netherlands)》2004,59(4):149-154

Wheat flour was separately substituted with fenugreek flour (raw, soaked, and germinated) at 5–20% levels for product making. Nutrient analysis of the blends, product development, and their acceptability were carried out. Replacement of wheat flour with fenugreek flour increased the protein, fat, lysine, minerals, and dietary fibre contents proportionately to the level of substitution. Among the composite flours, the blends containing germinated fenugreek flour were found superior in nutritional quality compared to others. However, products, viz., bread, biscuits, noodles, and macaroni prepared from the wheat–fenugreek blends at 10, 15, and 20% levels, were found organoleptically acceptable.  相似文献   

Abundance of rare earth elements in rice paddy soils from three regions of Sri Lanka     

Rohana?ChandrajithEmail author  Chandrasekara?Bandara?Dissanayake  Heinz?Jürgen?Tobschall 《Paddy and Water Environment》2004,2(3):163-169

Very few studies deal with the rare earth element (REE) content within paddy soil systems. This paper presents, for the first time, the distribution of REEs in paddy soils from three different regions in Sri Lanka. Seventy samples from the Kalutara and Kandy regions located in the Wet Zone and Anuradhapura region in the Dry Zone were selected for this study. ICP-MS measurements were performed on the soil samples to determine their respective REE concentrations. The sum content of all the REEs (REE) in these three regions were 182, 186 and 132 g/g, respectively. The mean concentrations for the 70 soil samples in µg/g were 35(La), 77 (Ce), 7.6 (Pr), 27.6 (Nd), 4.8 (Sm), 0.87 (Eu), 4.1 (Gd), 0.54 (Tb), 2.91 (Dy), 0.56 (Ho), 1.57 (Er), 0.21(Tm), 1.44 (Tb), and 0.23 (Lu). The chondrite-normalized REE patterns of the paddy soils from the three study areas were similar, which may be a reflection of comparable parent materials. Kalutara soils, which are richer in organic matter and kaolinite, showed a higher lighter REE content and lower heavy REE content with a more pronounced negative Eu anomaly with respect to the other regions. Whilst this may be a result of subtle differences in soil parent materials, it could also reflect secondary processes related to clay mineral and organic matter adsorption of REEs in paddy soils  相似文献   

Dyeing performance of disperse dyes based on 2-aminothiazole for cellulose triacetate and nylon fibers     

Hari?Raghav?MaradiyaEmail author  Vithal?Soma?Patel 《Fibers and Polymers》2002,3(1):43-48

A series of monoazo disperse dyes based on 2-amino-4-phenylthiazole was prepared using variousN,N-dialkylaniline derivatives as the coupling component. The dyes were characterized by IR spectral studies, visible absorption spectroscopy and elemental analysis. The dyeing performance of these dyes was assessed on cellulose triacetate and nylon fibers. These dyes were found to give a wide range of colour shades varying from bright red to royal blue with very good depth, brightness and levelness on fibers. The dyed fibers showed good to very good light fastness and very good to excellent fastness to washing, perspiration, rubbing and sublimation. The dyebath exhaustion and fixation on the fibers were found to be very good.  相似文献   

Polyphenol-Rich Extract of Fenugreek Seeds Protect Erythrocytes from Oxidative Damage     

Kaviarasan S  Vijayalakshmi K  Anuradha CV 《Plant foods for human nutrition (Dordrecht, Netherlands)》2004,59(4):143-147

A polyphenol-rich extract from the seeds of fenugreek was evaluated for its protective effect against hydrogen peroxide(H₂O₂)-induced oxidation in normal and diabetic human erythrocytes (RBCs). RBCs, preincubated with increasing amounts of fenugreek seed extract and challenged with H₂O_2, were analyzed for hemolysis and lipid peroxidation. RBCs from diabetic subjects were more susceptible to oxidative hemolysis and lipid peroxidation than those from normal subjects. However preincubation with the polyphenol-rich extract significantly reduced the oxidative modifications in both the groups. The inhibition of lipid peroxidation was concentration-dependent up to 100 l of extract, which contained 0.75mM gallic acid equivalent (GAE) of phenolic compounds. These findings demonstrate the potent antioxidant properties of the fenugreek seeds.  相似文献