A pilot-scale rubberwood dryer was constructed and injected with superheated steam and hot air to study the effect of the hybrid system on the drying rate and mechanical properties of the wood. A total of 300 pieces of rubberwood boards, each with dimensions of 1000 mm long × 76.2 mm wide × 25.4 mm thick, were stacked in 1.0 m × 1.0 m × 1.7 m (1.7 m3) pallet. The stack was impinged with alternating cycles of superheated steam and hot air. The time required for conventional drying was 168 hours, but the drying time for the hybrid system was only 64 hours, resulting in a 62% reduction. After being dried, the rubberwood boards were mechanically tested for static bending, compression strength, hardness, and shear strengths. From the mechanical tests, the hybrid drying system using superheated steam and hot air had no significant effect on the mean shear strength parallel-to-grain; however; the mean compression strength parallel-to-grain was reduced by 24.2% and the mean MOR by 21.4%. Nonetheless, the mean MOE was increased by 30.4% and the mean of hardness by 16.4%. 相似文献
In this paper, a simple and efficient strategy of one-pot synthesis of Ag doped TiO2/ZnO photocatalyst was developed using hydrothermal process. Simultaneous crystallization of Ag and ZnO crystals from their precursor solution containing P25 (TiO2) NPs could form effectively bonded Ag/TiO2/ZnO composite photocatalyst during hydrothermal treatment. Several analytical techniques, including scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray diffraction (XRD), FT-IR spectroscopy, and photoluminescence spectroscopy have been used to characterize the resulting Ag/TiO2/ZnO photocatalyst. Results showed that ZnO nano-flowers doped with TiO2 and Ag NPs were formed by this simple facile one-step process. The unique properties of Ag NPs on binary semiconductor composite not only provide the decreased rate of electron–hole separation but also prevent from the loss of photocatalyst during recovery due to the fixed attachment of Ag and TiO2 NPs on the surface of flower shaped large ZnO particles. Therefore, as-synthesized composite is an economically and environmentally friendly photocatalyst. 相似文献
Silicon nitride and titanium oxide coatings have been used to reduce the reflection losses from silicon solar cells. Both 100-mm-diameter circular and 100 × 100 mm pseudo-square single crystalline silicon solar cells have been used in the present studies. More than 27% enhancement in the short circuit current has been demonstrated in polished cells using screen printed titanium oxide antireflection coating. Solar cells made from textured silicon wafers were used for plasma enhanced CVD grown silicon nitride antireflection coating on them. In these cells more than 23% enhancement in short-circuit current has been observed after silicon nitride antireflection coating. 相似文献
For a series of catalysts containing 1 wt. % Pt and SnPt ratios ranging from ca. 1 to 8, the only crystalline alloy phase detected by XRD was SnPt (11). The XRD intensity of lines for the SnPt (11) alloy phase increase with increasing SnPt ratios, indicating the presence of unalloyed Pt in the samples containing low tin loadings. 相似文献
Ethanol was used for the extraction and purification of lipids from the biomass of the microalga Phaeodactylum tricornutum. This microalga is an oil‐rich substrate with a high proportion of eicosapentaenoic acid (EPA). The process consisted of two steps. First, ethanol (96% vol/vol) was used to extract the lipids from the lyophilized biomass. Second, a biphasic system was formed by adding water and hexane to the extracted crude oil. In this way, most of the lipids were transferred to the hexanic phase while most impurities remained in the hydroalcoholic phase. The first step was carried out by two consecutive extractions at room temperature, each with 5 mL ethanol per gram of biomass, for 10 and 1.25 h, respectively. Under these conditions, over 90% of the saponifiable lipids in the biomass were extracted. In the second step, the percentage of water in the hydroalcoholic phase, the hexane/hydroalcoholic phase ratio and the number of extraction steps were optimized. A water content of 40% vol/vol in the hydroalcoholic phase provided the highest lipid recovery. A recovery yield of 80% was obtained by four consecutive extractions with a hexane/hydroalcoholic phase ratio of 0.2 (vol/vol). Equilibrium distribution data of the lipids between the hydroethanolic and the hexanic phases were also obtained in order to predict the lipid recovery yield of the extraction. This process is an alternative to the traditional methods of lipid extraction, which uses less toxic solvents and reduces the total amount of solvents used. 相似文献
The composite membranes of PVDF/TiO2 were prepared by a phase-inversion technique. Different amounts of TiO2 with respect to the weight of the polymer were incorporated in the casting solution to study qualitatively and quantitatively the antifouling property of the membrane. The membrane morphology was studied using a high-resolution scanning electron microscopy and atomic force microscopy, whereas the crystalline nature was studied using X-ray diffraction method. The interfacial interactions between foulants and TiO2 immobilized membranes were also evaluated using the extended Derjaguin–Landau–Verwey–Overbeek (XDLVO) approach. The XDLVO theory revealed an increase in repulsive interactive energy barrier with an increase in TiO2 loading, thus causing to improve the antifouling property of the membrane. Intercalation of TiO2 nanoparticles efficiently improved the porosity and wettability of the polymeric membranes, which could be confirmed by the contact angle analyzer analysis. The modified PVDF membranes exhibited excellent antimicrobial properties against Gram-negative Escherichia coli as confirmed from the halo zone and activity test. The permeation experimental results also showed high protein rejection of bovine serum albumin and humic acid (foulant) for membranes with optimum TiO2 loading of 0.01 g/g of PVDF polymer. However, at a concentration of 0.02 g TiO2/g of PVDF a negative effect on the membrane property was observed due to the former non-uniform distribution.
The periportal (PP) and perivenous (PV) zones of the liver acinus differ in enzyme complements and capacities for cholesterol
and bile acid synthesis and other metabolic processes. The aim of this investigation was to determine the acinar distribution
of the catalytic activity of the enzymes governing the formation and hydrolysis of cholesteryl esters using PP and PV hepatocytes
from normal or cholestyramine-fed rats. The hepatocyte subpopulations were isolated by centrifugal elutriation, characterized
according to the distribution pattern of a number of cell parameters and marker enzymes, and assayed for acyl-CoA: cholesterol
acyltransferase (ACAT) and lysosomal, cytosolic and microsomal cholesteryl ester hydrolase (CEH). In normally fed rats, no
zonation was found in the activity of lysosomal CEH and ACAT, and the activity of both cytosolic and microsomal CEH zonated
toward the PV zone of the acinus. Concentrations of free and esterified cholesterol in homogenates, cytosol, and microsomes
of PP and PV cells were, however, similar. Cholestyramine raised significantly the PV/PP ratio of ACAT because of an exclusive
PP reduction of activity and abolished the heterogeneity in microsomal CEH because of a greater inhibitory PV response, whereas
the PV dominance of cytosolic CEH and the homogeneous distribution of lysosomal CEH were unaffected. These results demonstrated
homogeneity within the liver acinus for the enzymatic degradation of endocyted lipoprotein-derived cholesteryl esters, a structural
zonation of the cytosolic CEH and a dynamic zonation of ACAT and the microsomal CEH, with a PV dominance of the enzymatic
capacity for the degradation of stored cholesteryl esters in normal livers. 相似文献
In this work, an electrically conductive powder mixture of alumina, silicon carbide whiskers, and titanium carbide has been used to obtain cutting tools with a standard SNGN geometry after machining spark plasma sintered disks with 150 mm in diameter and 10 mm height. The obtained cutting inserts from the sintered blanks were used in real conditions in order to make a wear study of this composition compared to the alumina‐silicon carbide whiskers inserts available in the market. In parallel, pin on disk wear studies were performed. Results are discussed in terms of the different properties and microstructural features of the different ceramic composites. 相似文献
As part of a program to identify as many as possible of the components of the pecan weevil,Curculio caryae (Horn), the hydrocarbons from males, females, and larvae were isolated by solvent extraction and column chromatography and subjected to gas liquid chromatographymass spectrometry analysis. n-Alkanes from C14−C32 in the larvae and unsaturated and branched chain hydrocarbons from C20−C32 in males and females were found. There are no significant differences between the hydrocarbons of the male and female pecan weevils. 相似文献