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161.
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163.
Zhang F Gu W Xu P Tang S Xie K Huang X Huang Q 《Waste management (New York, N.Y.)》2011,31(6):1333-1338
Composting is the biological degradation and transformation of organic materials under controlled conditions to promote aerobic decomposition. To find effective ways to accelerate composting and improve compost quality, numerous methods including additive addition, inoculation of microorganisms, and the use of biosurfactants have been explored. Studies have shown that biosurfactant addition provides more favorable conditions for microorganism growth, thereby accelerating the composting process. However, biosurfactants have limited applications because they are expensive and their use in composting and microbial fertilizers is prohibited. Meanwhile, alkyl polyglycoside (APG) is considered a “green” surfactant. This study aims to determine whether APG addition into a compost reaction vessel during 28-day composting can enhance the organic matter degradation and composting process of dairy manure. Samples were periodically taken from different reactor depths at 0, 3, 5, 7, 14, 21, and 28 days. pH levels, electrical conductivity (EC), ammonium and nitrate nitrogen, seed germination indices, and microbial population were determined. Organic matter and total nitrogen were also measured.Compared with the untreated control, the sample with APG exhibited slightly increased microbial populations, such as bacteria, fungi, and actinomycetes. APG addition increased temperatures without substantially affecting compost pH and EC throughout the process. After 28 days, APG addition increased nitrate nitrogen concentrations, promoted matter degradation, and increased seed germination indices. The results of this study suggest that the addition of APG provides more favorable conditions for microorganism growth, slightly enhancing organic matter decomposition and accelerating the composting process, improving the compost quality to a certain extent. 相似文献
164.
采用浸渍法制备了四氨基酞菁钯(PdTAPc)/γ-Al_2O_3负载型光催化剂,采用UV-Vis,FTIR,XRD,SEM技术对其进行了表征,并将其用于罗丹明B的可见光催化降解,考察了光催化剂加入量、溶液pH、H_2O_2加入量、反应温度对罗丹明B降解效果的影响,并对光催化剂的稳定性进行了测试。表征结果显示,PdTAPc以圆片状负载于γ-Al_2O_3上,二者的结构均未发生明显变化。实验结果表明:在光催化剂加入量1.6 g/L、溶液pH 7.0、H_2O_2加入量12 mmol/L、反应温度20℃的优化条件下反应120 min,罗丹明B(质量浓度0.05 g/L)的降解率高达95%;光催化剂具有较高的稳定性,使用4次后罗丹明B的降解率仍高于85%。 相似文献
165.
166.
Yajun Lv Weizhun Jin Yan Yang Xinzhong Zhang Fangyi Ding 《International Journal of Green Energy》2017,14(11):916-924
This paper aims to reveal the heat transfer mechanism of low-temperature phase change material (PCM) and design PCM heat storage device in building heating environment. Firstly, low-temperature binary PCMs of lauric acid and stearic acid are prepared, and their thermal properties are investigated by DSC. Then, shell and tube latent heat thermal energy storage units are conducted, and heat transfer experiments are carried out to analyze the heat transfer mechanism of PCM. The results demonstrate that natural convection plays an important role in heat transfer process, and the heat storage efficiency of PCMs can be significantly enhanced by increasing the fin width and improving the inlet heat transfer fluid (HTF) temperature. Furthermore, some proposals are put forward to guide the design of PCM storage device in building heating environment. 相似文献
167.
J.M. Zhang T. Wang A.J. Ding X.H. Zhou L.K. Xue C.N. Poon W.S. Wu J. Gao H.C. Zuo J.M. Chen X.C. Zhang S.J. Fan 《Atmospheric environment (Oxford, England : 1994)》2009,43(2):228-237
Knowledge on atmospheric abundance of peroxyacetyl nitrate (PAN) is important in assessing the severity of photochemical pollution, and for understanding chemical transformation of reactive odd nitrogen and its impact on the budget of tropospheric ozone (O3). In summer 2006, continuous measurements of PAN were made using an automatic GC–ECD analyzer with an on-line calibrator at a suburban site of Lanzhou (LZ) and a remote site of Mt. Waliguan (WLG) in western China, with concurrent measurements of O3, total reactive nitrogen (NOy) and carbon monoxide (CO). At LZ, several photochemical episodes were observed during the study, and the average mixing ratio of PAN (plus or minus standard deviation) was 0.76 (±0.89) ppbv with the maximum value of 9.13 ppbv, compared to an average value of 0.44 (±0.16) ppbv at remote WLG. The PAN mixing ratios in LZ exhibited strong diurnal variations with a maximum at noon, while enhanced concentrations of PAN were observed in the evening and a minimum in the afternoon at WLG. The daily O3 and PAN concentration maxima showed a strong correlation (r2 = 0.91) in LZ, with a regression slope (PAN/O3) of 0.091 ppbv ppbv?1. At WLG, six well-identified pollution plumes (lasting 2–8 h) were observed with elevated concentrations of PAN (and other trace gases), and analysis of backward particle release simulation shows that the high-PAN events at WLG were mostly associated with the transport of air masses that had passed over LZ. 相似文献
168.
Yu Ren Aijun Ding Tao Wang Xinhua Shen Jia Guo Jiamin Zhang Yan Wang Pengju Xu Xinfeng Wang Jian Gao Jeffrey L. Collett 《Atmospheric environment (Oxford, England : 1994)》2009,43(9):1702-1711
Measurement of ambient gas-phase total peroxides was performed at the summit of Mount Tai (Mt. Tai, 1534 m above sea level) in central-eastern China during March 22–April 24 and June 16–July 20, 2007. The hourly averaged concentration of peroxides was 0.17 ppbv (± 0.16 ppbv, maximum: 1.28 ppbv) and 0.55 ppbv (± 0.67 ppbv, maximum: 3.55 ppbv) in the spring and summer campaigns, respectively. The average concentration of peroxides at Mt. Tai, which is in a heavily polluted region, was much lower than hydrogen peroxide measurements made at some rural mountain sites, suggesting that significant removal processes took place in this region. An examination of diurnal variation and a correlation analysis suggest that these removal processes could include chemical suppression of peroxide production due to the scavenging of peroxy and hydroxy radicals by high NOx, wet removal by clouds/fogs rich in dissolved sulfur dioxide which reacts quickly with peroxides, and photolysis. These sinks competed with photochemical sources of peroxides, resulting in different mean concentrations and diurnal pattern of peroxides in the spring and summer. A principal component analysis was conducted to quantify the major processes that influenced the variation of peroxide concentrations. This analysis shows that in the spring photochemical production was an important source of peroxides, and the major sink was scavenging during upslope transport of polluted and humid air from the lower part of the planetary boundary layer (PBL) and wet removal by synoptic scale clouds. During the summer, highly polluted PBL air (with high NOx) was often associated with very low peroxides due to the chemical suppression of HO2 by high NOx and wet-removal by clouds/fogs in this sulfur-rich atmosphere, especially during the daytime. Higher concentrations of peroxides, which often appeared at mid-nighttime, were mainly associated with subsidence of air masses containing relatively lower concentrations of NOy. 相似文献
169.
A new direct thermal desorption-GC/MS method: Organic speciation of ambient particulate matter collected in Golden, BC 总被引:1,自引:0,他引:1
Luyi C. Ding Fu Ke Daniel K.W. Wang Tom Dann Claire C. Austin 《Atmospheric environment (Oxford, England : 1994)》2009,43(32):4894-4902
Particulate matter having an aerodynamic diameter less than 2.5 μm (PM2.5) is thought to be implicated in a number of medical conditions, including cancer, rheumatoid arthritis, heart attack, and aging. However, very little chemical speciation data is available for the organic fraction of ambient aerosols. A new direct thermal desorption-gas chromatography/mass spectrometry (TD-GC/MS) method was developed for the analysis of the organic fraction of PM2.5. Samples were collected in Golden, British Columbia, over a 15-month period. n-Alkanes constituted 33–98% by mass of the organic compounds identified. PAHs accounted for 1–65% and biomarkers (hopanes and steranes) 1–8% of the organic mass. Annual mean concentrations were: n-alkanes (0.07–1.55 ng m−3), 16 PAHs (0.02–1.83 ng m−3), and biomarkers (0.02–0.18 ng m−3). Daily levels of these organics were 4.89–74.38 ng m−3, 0.27–100.24 ng m−3, 0.14–4.39 ng m−3, respectively. Ratios of organic carbon to elemental carbon (OC/EC) and trends over time were similar to those observed for PM2.5. There was no clear seasonal variation in the distribution of petroleum biomarkers, but elevated levels of other organic species were observed during the winter. Strong correlations between PAHs and EC, and between petroleum biomarkers and EC, suggest a common emission source – most likely motor vehicles and space heating. 相似文献
170.
Liming Zhang Dongsheng Yu Xuezheng Shi David C. Weindorf Limin Zhao Weixin Ding Hongjie Wang Jianjun Pan Changsheng Li 《Atmospheric environment (Oxford, England : 1994)》2009,43(17):2737-2746
Quantifying greenhouse gas (GHG) emissions from wetland ecosystems is a relatively new issue in global climate change studies. China has approximately 22% of the world's rice paddies and 38% of the world's rice production, which are crucial to accurately estimate the global warming potential (GWP) at regional scale. This paper reports an application of a biogeochemical model (DeNitrification and DeComposition or DNDC) for quantifying GWP from rice fields in the Tai-Lake region of China. For this application, DNDC is linked to a 1:50,000 soil database, which was derived from 1107 paddy soil profiles compiled during the Second National Soil Survey of China in the 1980–1990s. The simulated results show that the 2.34 Mha of paddy soil cultivated in rice–wheat rotation in the Tai-Lake region emitted about ?1.48 Tg C, 0.84 Tg N and 5.67 Tg C as CO2, N2O, and CH4 respectively, with a cumulative GWP of 565 Tg CO2 equivalent from 1982 to 2000. As for soil subgroups, the highest GWP (26,900 kg CO2 equivalent ha?1 yr?1) was linked to gleyed paddy soils accounting for about 4.4% of the total area of paddy soils. The lowest GWP (5370 kg CO2 equivalent ha?1 yr?1) was associated with submergenic paddy soils accounting for about 0.32% of the total area of paddy soils. The most common soil in the area was hydromorphic paddy soils, which accounted for about 53% of the total area of paddy soils with a GWP of 12,300 kg CO2 equivalent ha?1 yr?1. On a regional basis, the annual averaged GWP in the polder, Tai-Lake plain, and alluvial plain soil regions was distinctly higher than that in the low mountainous and Hilly soil regions. As for administrative areas, the average annual GWP of counties in Shanghai city was high. Conversely, the average annual GWP of counties in Jiangsu province was low. The high variability in soil properties throughout the Tai-Lake region is important and affects the net greenhouse gas emissions. Therefore, the use of detailed soil data sets with high-resolution digital soil maps is essential to improve the accuracy of GWP estimates with process-based models at regional and national scales. 相似文献