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91.
Cynthia Salas 《Drying Technology》2014,32(3):301-310
Tectona grandis and Gmelina arborea are common in commercial reforestation in the tropics. However, color variations, moisture content, and drying defects are also present in dried lumber. Moisture content variations, drying defects, and color changes were evaluated in the present work for three drying methods (kiln, solar, and air drying) during three seasons (dry, rainy, and transition season) in Costa Rica. According to the results, kiln drying had the fastest drying times, regardless of the season. On the other hand, air drying had slower drying time and higher final moisture content. With regard to defects, kiln drying produced the highest number and magnitude of defects in both species, whereas air drying showed the lowest quantity and severity of defects. No variations due to the drying methods or the season were observed in check and split, though solar drying presented intermediate values in all drying defects. The seasons of the year did not present any effect on drying defects. Finally, T. grandis dried lumber is darker than green lumber, and dried G. arborea wood is clearer. In addition, there is an increase in red ( a * ) and yellow ( L * ) tonalities, and color changes (Δ E * ) are considered perceptible or very perceptible in both species. No differences were found among the three drying methods in Δ E * , although the season of the year affected dif L * and dif C * significantly. 相似文献
92.
Hasan Kouchakzadeh Seyed Abbas Shojaosadati Fazel Shokri 《Chemical Engineering Research and Design》2014
Herein, the poorly water-soluble drug, Tamoxifen (Tmx), was loaded in the amphipathic matrix of human serum albumin (HSA) nanoparticles by a modified desolvation method. In order to enhance the drug loading (DL) and drug entrapment efficiency (DEE) (<2% and 10%, respectively), ultrasonication of Tmx-HSA mixture was performed prior to desolvation process. Tmx loading and entrapment efficiency were optimized by employment of the response surface methodology (RSM)-central composite design (CCD) of experiments. Under the optimum conditions of 1.59 mg Tmx/ml concentration, 7.76 pH and 5 h incubation of HSA-Tmx, the DL of 6.7% and DEE of 74% are achievable. Particles with the average size of 195 nm, zeta potential of −21 mV and polydispersity index of 0.09 were produced under these conditions. A more sustained Tmx release behavior was observed from polyethylene glycol (PEG) conjugated nanoparticles in comparison to the non-PEGylated ones. The short-term stability investigation showed no alteration in physicochemical properties of nanoparticles at 4 and 37 °C, but small increase in nanoparticles size was observed after three months of storage at room temperature. This is the first report for efficient production of a Tmx delivery system based on HSA nanoparticles. 相似文献
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文章于2014年4月1日~4月30日在吉林师范大学对大气污染物PM10、NOX和SO2进行监测。采暖期,PM10、NOx和SO2的浓度分别为150.9μg/m3、46.4μg/m3和27.3μg/m3,虽没有超过空气质量标准,但是其数值都比非采暖期高。采暖期PM10浓度为非采暖期的1.6倍,NOx和SO2的浓度分别为非采暖期的1.3倍和1.8倍。无论是采暖期还是非采暖期,AQI指数与PM10浓度呈强相关性,说明PM10为四平市首要大气污染物。 相似文献
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98.
矿山生态环境保护与恢复治理评价指标体系的构建 总被引:1,自引:0,他引:1
由于矿山生态保护与恢复治理涉及的范围广、要素多、联系复杂,因此在矿山生态环境保护与恢复治理评价指标体系的构建过程中,指标的选取与量化具有模糊性和不确定性。利用层次分析法理论建立了矿山生态环境保护与恢复治理评价指标体系,经过专家打分,采用层次分析法计算出各评价指标的权重,从而定量分析了各指标对矿山生态环境保护与恢复治理影响的重要性。该研究可为矿山生态环境保护与恢复治理效果评价提供参考依据。 相似文献
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100.
Cement-fly ash-gravel (CFG) piles comprise one of the novel ground-improvement methods. They are attracting considerable attention, as their beneficial role in accessible soft foundations is being increasingly exploited by the surging urban industrial development in China. Despite their recognised significance, however, the load-settlement behaviour of CFG piles is poorly understood, particularly in the context of probabilistic assessments. This study focuses on six full-scale CFG pile load test datasets, consisting of 245 samples collected at six sites in the Beijing region, under static axial compression loading. As a part of this investigation, a regression curve is applied to the load-settlement data for each load test in the database using a two-parametric hyperbolic or power law curve-fitting equation. Moreover, an assessment of the multiple load-displacement curves, based on the full set of pile load measurements conducted at a particular test site, reveals that the scatter observed in the regression parameter values is mainly caused by the inherent soil variability.Thus, a bivariate copula-based mixed distribution is chosen to represent the dependence between these regression parameters. A simple copula-based simulation model is used to estimate the reliability index at any specific allowable settlement for the serviceability limit state (SLS) design. The correlation coefficients in the copula-based distributions of the regression parameters are proven to have an impact on the reliability index of this pile foundation. A scatter analysis of the load-displacement behaviour provides insight into the probabilistic design of site-specific CFG pile foundations. 相似文献