NOx photocatalytic degradation on active concrete road surface — from experiment to real-scale application

The use of titanium dioxide (TiO₂) as a photocatalyst in concrete pavements has received considerable attention in recent years due to its ability to decontaminate via photocatalytic processes. The objective of this study is to assess the effectiveness of activated concrete road in the degradation of nitrogen oxides (NO_x). We have used a TiO₂ and activated carbon (AC) permeable spray solution to coat concrete to assess its NO_x purifying ability. A number of experiments were undertaken to ascertain the conditions that affect NO_x purification. Indoor simulation experiments with active concrete road at optimum conditions show that it has good purification ability, self-regeneration and repetition ability, with a minimum decontamination rate for NO and NO₂ of 37.4% and 25.84%, respectively. Outdoor experiments show that the photodegradation of NO_x is related to light intensity and temperature. As the light intensity increases the reaction rate increases, and conversely as temperature increases the reaction rate decreases.     

孕鼠PFOS暴露对糖皮质激素水平及胎鼠生长发育的影响

为探究孕期全氟辛烷磺酸(PFOS)暴露与母源糖皮质激素(GC)水平、胎鼠生长发育之间的关系,将孕期为12 d(GD12)的24只SD雌性大鼠,随机分为4组给予不同剂量的PFOS(0,5,10,20 mg·kg-1),连续灌胃7 d,在GD19时对孕鼠和胎鼠的体重、胎鼠肝脏系数和肝脏生化指标、孕鼠血清的生化指标和GC水平、胎盘11β-羟基类固醇脱氢酶2(11β-HSD2)的酶学活性和胰岛素样生长因子-1(IGF-1)的mRNA表达水平分别进行检测。结果表明,与对照组相比:PFOS 20 mg·kg-1组,母鼠体重、胎鼠体重和体长显著下降(P0.001);PFOS 20 mg·kg-1组,胎鼠肝脏脏器系数低于对照组(P0.001);PFOS 10 mg·kg-1组,胎鼠肝脏中的酶活性(ALT、AST和ALP等)显著升高(P0.001);PFOS 20 mg·kg-1组,孕鼠血清GC水平升高(P0.05);胎盘IGF-1的mRNA表达水平随PFOS剂量升高而降低;胎盘11β-HSD2的活性随PFOS剂量升高而降低。研究表明,孕期暴露PFOS可以导致胎鼠肝脏毒性,降低胎盘11β-HSD2氧化活性导致GC浓度升高,进而影响胎鼠的生长发育。     

Investigation of the decomposition reaction and dust explosion characteristics of crystalline dicumyl peroxide

The dicumyl peroxide (DCP) is widely used as a polymerization initiator, catalyst and vulcanizing agent in the chemical industry. A number of accidents have been caused by its thermal instability in storage or manufacturing process. Thus, its hazard characteristics have to be clearly identified. First of all, the differential scanning calorimeter (DSC) is used to measure the heat of decomposition reaction, which can contribute to understanding the reaction characteristics of DCP. The accelerating rate calorimeter (ARC) is used to measure the rates of temperature and pressure rises of decomposition reaction, and then the kinetics parameters are estimated. Furthermore, the MIKE 3 apparatus and the 20-l-Apparatus are used to measure and analyze the dust explosion characteristics of DCP at room temperature and atmospheric pressure. Finally, Semenov's thermal explosion theory is applied to investigate the critical runaway condition and the stability criterion of decomposition reaction, and to build the relationship of critical temperature, convective heat transfer coefficient, heat transfer surface area and ambient temperature. These results contribute to improving the safety in the reaction, transportation and storage processes of DCP.     

Variability and predictability of sea-level extremes in the Hawaiian and U.S.-Trust Islands—a knowledge base for coastal hazards management

The objective of this study is to provide an improved climatology of sea level extremes on seasonal and long-term time scales for Hawaii and the U.S-Trust islands. Observations revealed that the Hawaiian and U.S.-Trust islands, by and large, display a strong annual cycle. For estimating the statistics of return period, the three-parameter generalized extreme value (GEV) distribution is fitted using the method of L-moments. In the context of extremes (20- to 100-year return periods), the deviations in most of the Hawaiian Islands (except at Nawiliwili and Hilo) displayed a moderate sea-level rise (i.e., close to 200 mm), but the deviations in the U.S.-Trust islands displayed a considerably higher rise (i.e., more than 300 mm) in some seasons due to typhoon-related storm surges. This rise may cause damage to roads, harbors, and unstable sandy beaches. Correlations between the El Niño-Southern Oscillation (ENSO) climate cycle and the variability of seasonal sea level have been investigated. Results show that correlation for the station located west of the International Date Line (DL) is strong, but it is moderate or even weaker for stations east of the DL. The skill of SST-based Canonical Correlation Analyses (CCA) forecasts was found to be weak to moderate (0.4–0.6 for Honolulu, Kahului, Hilo, and Wake, and 0.3 or below for Kahului, Mokuoloe, and Johnston). Finally, these findings are synthesized for evaluating the potential implications of sea level variability in these islands.     

Sterol production and phytosterol bioconversion in two species of heterotrophic protists, Oxyrrhis marina and Gyrodinium dominans

The kinetics and efficiency of sterol production and bioconversion of phytosterols in two heterotrophic protists Oxyrrhis marina and Gyrodinium dominans were examined by feeding them two different algal species (Rhodomonas salina and Dunaliella tertiolecta) differing in sterol profiles. R. salina contains predominantly brassicasterol (?99%) and <2% cholesterol. The major sterols in D. tertiolecta are ergosterol (45–49%), 7-dehydroporiferasterol (29–31%) and fungisterol (21–26%). O. marina fed R. salina metabolized dietary brassicasterol to produce 22-dehydrocholesterol and cholesterol. O. marina fed D. tertiolecta metabolized dietary sterols to produce cholesterol, 22-dehydrocholesterol, brassicasterol and stigmasterol. G. dominans fed either R. salina or D. tertiolecta metabolized dietary sterols to make cholesterol, brassicasterol and a series of unknown sterols. When protists were fed R. salina, which contains cholesterol, the levels of cholesterol were increased to a magnitude of nearly 5- to 30-fold at the phytoplankton-heterotrophic protist interface, equivalent to a production of 172.5 ± 16.2 and 987.7 ± 377.7 ng cholesterol per mg R. salina carbon consumed by O. marina and G. dominans, respectively. When protists were fed D. tertiolecta, which contains no cholesterol, a net production of cholesterol by the protists ranged from 123.2 ± 30.6 to 871.8 ± 130.8 ng per mg algal C consumed. Cholesterol is not only the dominant sterol, but a critical precursor for many physiologically functional biochemicals in higher animal. As intermediates, these heterotrophic protists increase the amount of cholesterol at the phytoplankton–zooplankton interface available to higher trophic levels relative to zooplankton feeding on algae directly.     

硫磺回收装置扩能改造及效果分析

介绍了回收酸性气体生产硫磺的工艺原理与工艺流程,论述了影响硫磺回收装置生产能力的诸多因素与扩能改造的情况。扩能改造后,该装置的酸性气体处理量平均为976m^3／h,瞬时处理量可达1200m^3／h,硫磺的生产能力从4450t／a提高到7500t／a,生产能力提高了68．5％,装置总硫回收率达到93．5％。     

A review of 20-year applications of multi-attribute decision-making in environmental and water resources planning and management

Environment, Development and Sustainability - Multi-attribute decision-making (MADM) is an umbrella term to describe a series of mathematical frameworks that, in essence, enable the decision-makers...     

Comparison of the Photodegradation of Imazethapyr in Aqueous Solution,on Epicuticular Waxes,and on Intact Corn (Zea Mays) and Soybean (Glycine Max) Leaves

A direct, controlled comparison of the photodegradation of imazethapyr has been made between imazethapyr in aqueous solutions, imazethapyr on the surface of epicuticular waxes of corn and soybean plants, and imazethapyr on the surface of intact corn and soybean plant leaves. In some experiments, the imazethapyr solutions were allowed to evaporate partially or fully after application to better model environmental conditions. The photodegradation of imazethapyr was fastest in aqueous solutions (k?=?0.16?±?0.02?h^?1) and slowest on the surface of corn and soybean plants (k_corn?=?0.00048?±?0.001?h^?1 and k_soy?=?0.00054?±?0.003?h^?1). Experiments allowing evaporation during irradiation have intermediate rate constants (e.g., k_corn?=?0.082?±?0.005?h^?1). Finally, identification of photoproducts was also examined on epicuticular waxes of corn and soybean plants for the first time.     

中国农村居民煤炭消费及影响因素研究

农村居民煤炭消费牵涉到农村居民生活方式与能源转型、北方供暖清洁化改革、大气污染治理等重大改革实践,如何准确理解和研判现有的农村居民煤炭消费现状,并进而识别出科学、有效的减煤措施,已成为改善农村居民能源结构、治理农村地区煤炭消费、改善北方地区大气质量的重要手段之一。然而,现有对农村居民煤炭消费的统计数据可能存在一定低估,基础性数据的匮乏与不足严重阻碍了科学研究和公共决策。为了准确了解我国农村居民煤炭消费的现状、特征与空间分布,本文采用第三次中国家庭能源消费调查数据对农村居民的煤炭消费进行了核算,并针对户均煤炭消费量和地区农村居民煤炭消费总量进行了比较,在此基础上还考察了气候差异、资源禀赋、收入水平等因素对农村居民煤炭需求的影响。研究结果表明,2014年中国农村居民生活用煤炭消费总量为6 585.7万tce,平均每户煤炭消费量为347.2 kgce,其中供暖用煤占比96.9%,烹饪用煤占比3.1%。各省的户均煤炭消费和煤炭消费总量呈现显著的空间差异,其中:东北、西部地区农村居民户均煤炭消费量显著高于其他地区,北京及周边的河北、山东、山西、内蒙、辽宁和天津7个省、市的农村居民共消费了全国55%的农村生活用煤,其中北京周边的河北、山东和山西三省农村居民消费了全国46.6%的农村煤炭消费。地区煤炭资源禀赋、农村居民住房面积与供暖用煤需求显著正相关,而冬季户外温度、居民收入水平同煤炭需求之间关系不显著。未来政府应通过改善农村居民民生需求、推动农村能源转型、提高农村能源统计水平等途径来有效治理农村散煤消费。