ALBERT

Description: Aromatic hydrocarbons are important anthropogenic precursors of tropospheric ozone and secondary organic aerosols. Here, we measured ambient aromatic hydrocarbons from March 2012 to February 2014 at six rural sites in China's developed coastal regions. On average, benzene (B) comprised 〉 50% of total benzene (B), toluene (T), ethylbenzene (E), and xylenes (X) (BTEX) at sites in the Northeast China Plain (NECP) or in the North China Plain (NCP), whereas T, E, and X accounted for 〉 77% of total BTEX at sites in the Yangtze River Delta (YRD) and the Pearl River Delta (PRD) in the south. BTEX at the northern sites was significantly correlated ( p  〈 0.01) with combustion tracer-carbon monoxide (CO) but weakly correlated with traffic marker-methyl tert-butyl ether (MTBE), suggesting that their main sources were coal and biofuel/biomass burning with substantially elevated B levels during the winter heating period. In contrast, BTEX at the southern sites originated mainly from traffic-related and/or industrial emission sources, as indicated by the poor correlations with CO but highly significant ( p  〈 0.01) correlations with MTBE and tetrachloroethylene, an industrial emission tracer. The B/CO emission ratios from measurement agreed within a factor of two with that of a previous widely used emission inventory of China, but the T/CO ratio at the NECP site and the o-X/CO ratio at the NCP site were 29% and 38% of that in the inventory, respectively; the E/CO and X/CO ratios at the YRD site were 3.2-3.5 fold that in the emission inventory.

Description: The resource-development trajectory of developed countries after the Industrial Revolution of the eighteenth and nineteenth centuries can be portrayed as an “ environmental mountain ” (EM). It is important for developing countries to decouple their resource use from economic growth and tunnel through the EM. In this study, we embedded the decoupling indicators for resource use and waste emissions into EM curves to quantify China's progress in tunneling through the EM over a specific time period. Five case studies regarding the conditions required for decoupling energy consumption, crude steel production, cement production, CO 2 emissions, and SO 2 emissions from economic growth in China were conducted. The results indicated that during 1985–2010 the trajectories of energy consumption, and CO 2 and SO 2 emissions in China met the requirements for tunneling through the EM, but the trajectories of cement and steel production did not. Based on these results, suggestions regarding China's environmental policies are provided to enable the country to tunnel through the EM.

Description: Abstract Theory predicts Cu‐doped ZnO (ZnO:Cu) has p‐conductivity; however, this has only been demonstrated in a small number of experimental and mechanistic studies. In this paper, ZnO:Cu films were grown in situ with varying Cu content, prepared using radiofrequency atomic source–assisted molecular‐beam vapor deposition. The results indicate that ZnO:Cu films with dopant of Cu2+ only had n‐type behavior. As the Cu content increased, Cu+ was the major dopant and the ZnO:Cu films had p‐type behavior. However, excess Cu dopant resulted in the formation of second phases of Cu2O and Cu–Zn. The formation of a Cu–Zn phase increased the content of Zn vacancy, thus increasing hole concentration. Stronger alloy scattering decreased carrier mobility. Therefore, Cu+ dopant and Zn vacancy give ZnO:Cu films p‐conductivity properties.

Description: The mechanisms underlying the neurotoxicology of endemic fluorosis still remain obscure. To explore lactate dehydrogenase (LDH) leakage, intracellular Ca 2+ concentration ([Ca 2+ ] i ) and reactive oxygen species (ROS) production induced by fluoride, human neuroblastoma (SH-SY5Y) cells were incubated with sodium fluoride (NaF, 20, 40, 80 mg/L) for 24 h, with 40 mg/L NaF for 3, 6, 12, 18, 24 h, and N -acetyl- L -cysteine (NAC), ethyleneglycol-bis-(β-aminoethyl ether)- N , N , N ′, N ′-tetraacetic acid (EGTA), 1,2-bis( O -aminophenoxy)ethane- N , N , N ′, N ′-tetraacetic acid tetra(acetoxymethyl) ester (BAPTA-AM) alone or combined with fluoride (40 mg/L) respectively for 12 h in vitro . The results showed that the LDH levels in the 40 and 80 mg/L fluoride-treated groups were significantly higher than that of the control group (in the test level of 0.05, the difference were statistical significance). [Ca 2+ ] i and ROS reached a peak at 3 h and 12 h respectively after exposure to 40 mg/L fluoride. Fluoride coincubated with NAC (antioxidant) dramatically decreased ROS and LDH levels compared with the fluoride only group (in the test level of 0.05, the difference were statistical significance). However, fluoride-induced increase in [Ca 2+ ] i was not affected by NAC. BAPTA-AM (intracellular calcium chelator) markedly lowered fluoride-induced increase of [Ca 2+ ] i , ROS and LDH levels while EGTA (extracellular calcium chelator) have no effects on them. These results indicate that fluoride-related Ca 2+ release from the site of intracellular calcium storage causes the elevation of ROS contributing to the cytotoxicity in SH-SY5Y cells. © 2011 Wiley Periodicals, Inc. Environ Toxicol, 2011.

Description: The separation of liquid-gas flows is essential for many industrial processes. Computational fluid dynamics method that contains Algebraic Slip Mixture model and Reynolds Stress model is firstly adopted to analyze the impact of number of inlets, column-diameter ratio on the degassing performance of hydrocyclone. For separating the bubbles that are 5-50µm in size, the structures with 1-6 inlets and seven different column-diameter ratios (2.0-5.0) are simulated. The results show that multiport designs are more suitable for liquid-gas separation, particularly separation of small bubbles. However, as the number of inlets increases, the growth trend of separation efficiency becomes slow. In addition, the structure with H c =3.9·D n obtains the optimal separation performance. Moreover, a longer column section is beneficial to small bubbles, but results in a greater loss of fluid energy.

Description: Current chemical transport models commonly under-simulate the atmospheric concentration of nitrous acid (HONO), which plays an important role in atmospheric chemistry, due to the lack or inappropriate representations of some sources in the models. In the present study, we parameterized up-to-date HONO sources into a state-of-the-art three-dimensional chemical transport model (WRF-Chem). These sources included (1) heterogeneous reactions on ground surfaces with the photo-enhanced effect on HONO production, (2) photo-enhanced reactions on aerosol surfaces, (3) direct vehicle and vessel emissions, (4) potential conversion of NO 2 at the ocean surface, and (5) emissions from soil bacteria. The revised WRF-Chem was applied to explore the sources of the high HONO concentrations (0.45-2.71 ppb) observed at a suburban site located within complex land types (with artificial land covers, ocean, and forests) in Hong Kong. With the addition of these sources, the revised model substantially reproduced the observed HONO levels. The heterogeneous conversions of NO 2 on ground surfaces dominated HONO sources contributing about 42% to the observed HONO mixing ratios, with emissions from soil bacterial contributing around 29%, followed by the oceanic source (~9%), photochemical formation via NO and OH (~6%), conversion on aerosol surfaces (~3%), and traffic emissions (~2%). The results suggest that HONO sources in suburban areas could be more complex and diverse than those in urban or rural areas and that the bacterial and/or ocean processes need to be considered in HONO production in forested and/or coastal areas. Sensitivity tests showed that the simulated HONO was sensitive to the uptake coefficient of NO 2 on the surfaces. Incorporation of the aforementioned HONO sources significantly improved the simulations of ozone, resulting in increases of ground-level ozone concentrations by 6-12% over urban areas in Hong Kong and the Pearl River Delta region. This result highlights the importance of accurately representing HONO sources in simulations of secondary pollutants over polluted regions.

Description: Condensate oil is a kind of light crude oil with API gravity higher than 50 degrees. The increasing production of condensate oil due to shale gas/natural gas booming has economically motivate refiners to add this valuable and abundant crude source into their feedstock. Many refineries, however, were originally built to process heavier crudes, whose design must be retrofitted to enable the processing of the changed feedstock. In this paper, the conceptual retrofit design of crude distillation units for processing condensate oil has been studied. Four retrofit designs are proposed and simulated including facilities of preflash column, atmospheric distillation unit, and vacuum distillation unit. All retrofit designs are comprehensively evaluated by steady-state modeling for feasibility check, energy consumption analysis for operating cost evaluation, and retrofit cost evaluation. With the help of Aspen Plus, Aspen Energy Analyzer, and Aspen Capital Cost Estimator, the developed methodology provides a quantitative technology support to identify the optimal retrofit design. A comparison of the results shows that the retrofit design with preflash columns in sequence potentially could be the most economical case.

Description: The mechanisms underlying the neurotoxicology of endemic fluorosis still remain obscure. To explore lactate dehydrogenase (LDH) leakage, intracellular Ca 2+ concentration ([Ca 2+ ] i ) and reactive oxygen species (ROS) production induced by fluoride, human neuroblastoma (SH-SY5Y) cells were incubated with sodium fluoride (NaF, 20, 40, 80 mg/L) for 24 h, with 40 mg/L NaF for 3, 6, 12, 18, 24 h, and N -acetyl- L -cysteine (NAC), ethyleneglycol-bis-(β-aminoethyl ether)- N , N , N ′, N ′-tetraacetic acid (EGTA), 1,2-bis( O -aminophenoxy)ethane- N , N , N ′, N ′-tetraacetic acid tetra(acetoxymethyl) ester (BAPTA-AM) alone or combined with fluoride (40 mg/L) respectively for 12 h in vitro . The results showed that the LDH levels in the 40 and 80 mg/L fluoride-treated groups were significantly higher than that of the control group (in the test level of 0.05, the difference were statistical significance). [Ca 2+ ] i and ROS reached a peak at 3 h and 12 h respectively after exposure to 40 mg/L fluoride. Fluoride coincubated with NAC (antioxidant) dramatically decreased ROS and LDH levels compared with the fluoride only group (in the test level of 0.05, the difference were statistical significance). However, fluoride-induced increase in [Ca 2+ ] i was not affected by NAC. BAPTA-AM (intracellular calcium chelator) markedly lowered fluoride-induced increase of [Ca 2+ ] i , ROS and LDH levels while EGTA (extracellular calcium chelator) have no effects on them. These results indicate that fluoride-related Ca 2+ release from the site of intracellular calcium storage causes the elevation of ROS contributing to the cytotoxicity in SH-SY5Y cells. © 2011 Wiley Periodicals, Inc. Environ Toxicol, 2011.