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Atmospheric composition

Graham Noctor, Amna Mhamdi
Ongoing human-induced changes in the composition of the atmosphere continue to stimulate interest in the effects of high CO2 on plants, but its potential impact on inducible plant defense pathways remains poorly defined. Recently, several studies have reported that growth at elevated CO2 is sufficient to induce defenses such as the salicylic acid pathway, thereby increasing plant resistance to pathogens. These reports contrast with evidence that defense pathways can be promoted by photorespiration, which is inhibited at high CO2...
August 12, 2017: Trends in Plant Science
Guan Sem Ho, Hasan Mohd Faizal, Farid Nasir Ani
High temperature thermal plasma has a major drawback which consumes high energy. Therefore, non-thermal plasma which uses comparatively lower energy, for instance, microwave plasma is more attractive to be applied in gasification process. Microwave-induced plasma gasification also carries the advantages in terms of simplicity, compactness, lightweight, uniform heating and the ability to operate under atmospheric pressure that gains attention from researchers. The present paper synthesizes the current knowledge available for microwave plasma gasification on solid fuels and waste, specifically on affecting parameters and their performance...
August 12, 2017: Waste Management
João T V Matos, Regina M B O Duarte, Sónia P Lopes, Artur M S Silva, Armando C Duarte
Organic Aerosols (OAs) are typically defined as highly complex matrices whose composition changes in time and space. Focusing on time vector, this work uses two-dimensional nuclear magnetic resonance (2D NMR) techniques to examine the structural features of water-soluble (WSOM) and alkaline-soluble organic matter (ASOM) sequentially extracted from fine atmospheric aerosols collected in an urban setting during cold and warm seasons. This study reveals molecular signatures not previously decoded in NMR-related studies of OAs as meaningful source markers...
August 11, 2017: Environmental Pollution
Pengrui Du, Rui Du, Weishan Ren, Zedong Lu, Pingqing Fu
Bacteria and fungi are primary constituents of airborne microbes in fine particulate matter (PM2.5) and significantly impact human health. However, hitherto, seasonal variation and effect of air pollution on microbial community composition and structure are poorly understood. This study analyzed the bacterial and fungal composition of PM2.5 under different air pollution levels during different seasons in Beijing. We altogether collected 75PM2.5 samples during four seasons from April 2014 to January 2015, under different air pollution levels and employed high-throughput sequencing methods to analyze microbial composition...
August 11, 2017: Science of the Total Environment
Mujahid Ali, Qunxing Huang, Bingcheng Lin, Binhang Hu, Wang Fei, Chi Yong
The aim of this paper is to present the effect of hydrolysis treatment on the thermal reaction characteristics of sludge and the leaching test of heavy metals contained in the sludge. Raw and hydrolysis treated sludge (at temperature of 200 °C and pressure 0.4MPa) samples were collected from local municipal sewage sludge treatment plant. Thermogravimetric analysis (TGA) was carried out between 25 to 900 °C at the heating rate of 10 and 20 °C/min under incineration and pyrolysis atmospheres. The leaching behavior of toxic heavy metals in the sludge was studied along with ash composition...
August 14, 2017: Environmental Technology
Olivier Couvert, Stéphanie Guégan, Bernard Hézard, Véronique Huchet, Adrienne Lintz, Dominique Thuault, Valérie Stahl
The effect of carbon dioxide, temperature, and pH on growth of Listeria monocytogenes and Pseudomonas fluorescens was studied, following a protocol to monitor microbial growth under a constant gas composition. In this way, the CO2 dissolution didn't modify the partial pressures in the gas phase. Growth curves were acquired at different temperatures (8, 12, 22 and 37 °C), pH (5.5 and 7) and CO2 concentration in the gas phase (0, 20, 40, 60, 80, 100% of the atmospheric pressure, and over 1 bar). These three factors greatly influenced the growth rate of L...
December 2017: Food Microbiology
Sanghee Lee, Changhee Han, Daechol Shin, Soon Do Hur, Seong Joon Jun, Young-Taeg Kim, Do-Seong Byun, Sungmin Hong
A total of 82 aerosol samples (PM10-2.5) were collected from June 18, 2015 to October 1, 2016 at the remote sea site, the Ieodo Ocean Research Station (IORS), in the East China Sea. Samples were analyzed for 10 elements (Al, Fe, Cu, Zn, As, Mo, Cd, Sb, Tl, and Pb) as well as Pb isotopic composition to characterize temporal variations in elemental concentration levels, and to identify the potential source regions of atmospheric pollutants transported over the remote East China Sea. The results showed that the annual average element concentrations were lowest compared to those at different sites in East Asia, suggesting a very clean background area of IORS, with values ranging from 114 ng m(-3) for Al to 0...
August 8, 2017: Environmental Pollution
Peng Wang, Laifei Cheng, Yani Zhang, Litong Zhang
SiC/Si3N4 composite nanofibers with in situ embedded graphite, which show highly efficient electromagnetic (EM) wave absorption performance in gigahertz frequency, were prepared by electrospinning with subsequent polymer pyrolysis and annealing. By means of incorporating graphite and Si3N4 into SiC , the EM wave absorption properties of the nanofibers were improved. The relationship among processing, fibers microstructure and their superior EM absorption performance were systematically investigated. The EM wave absorption capability, effective absorption bandwidth (EAB) of nanofibers can be simply controlled by adjusting annealing atmosphere and temperature...
August 11, 2017: ACS Applied Materials & Interfaces
Siddharth Iyer, Xucheng He, Noora Hyttinen, Theo Kurtén, Matti P Rissanen
The HO2 radical is an important atmospheric molecule that can potentially influence the termination of autoxidation processes of volatile organic compounds (VOCs) that lead to the formation of highly oxygenated multifunctional compounds (HOMs). In this work, we demonstrate the direct detection of the HO2 radical using an iodide-based chemical ionization mass spectrometer (iodide-CIMS). Expanding on the previously established correlation between molecule-iodide binding enthalpy and iodide-CIMS instrument sensitivity, the experimental detection of the HO2 radical was preceded by the quantum chemical calculation of the HO2*I(-) cluster (PBE/aug-cc-pVTZ-PP level), which showed a reasonably strong binding enthalpy of 21...
August 10, 2017: Journal of Physical Chemistry. A
Kazuya Nishina, Mirai Watanabe, Masami K Koshikawa, Takejiro Takamatsu, Yu Morino, Tatsuya Nagashima, Kunika Soma, Seiji Hayashi
Ecosystems of suburban landscapes (i.e., forest, inland water ecosystem) are threatened by high nitrogen (N) loadings derived from urban air pollutants. Forest ecosystems under high chronic N loadings tend to leach more N via streams. In the northern suburbs of Tokyo, N deposition loading on terrestrial ecosystems has increased over the past 30 years. In this region, we investigated nitrate concentrations in 608 independent small forested catchment water samples from northeastern suburbs of Tokyo. The nitrate concentrations varied from 0...
August 9, 2017: Scientific Reports
Chongjuan Chen, Jiazhu Li, Guoan Wang, Minrui Shi
Atmospheric nitrogen deposition affects nitrogen isotope composition (δ(15)N) in plants. However, both negative effect and positive effect have been reported. The effects of climate on plant δ(15)N have not been corrected for in previous studies, this has impeded discovery of a true effect of atmospheric N deposition on plant δ(15)N. To obtain a more reliable result, it is necessary to correct for the effects of climatic factors. Here, we measured δ(15)N and N contents of plants and soils in Baiwangshan and Mount Dongling, north China...
August 5, 2017: Science of the Total Environment
Katja Guilini, Miriam Weber, Dirk de Beer, Matthias Schneider, Massimiliano Molari, Christian Lott, Wanda Bodnar, Thibaud Mascart, Marleen De Troch, Ann Vanreusel
The unprecedented rate of CO2 increase in our atmosphere and subsequent ocean acidification (OA) threatens coastal ecosystems. To forecast the functioning of coastal seagrass ecosystems in acidified oceans, more knowledge on the long-term adaptive capacities of seagrass species and their epibionts is needed. Therefore we studied morphological characteristics of Posidonia oceanica and the structure of its epibiont communities at a Mediterranean volcanic CO2 vent off Panarea Island (Italy) and performed a laboratory experiment to test the effect of OA on P...
2017: PloS One
Daoran Li, Xiaohui Liang, Wei Liu, Jianna Ma, Yanan Zhang, Guangbin Ji, Wei Meng
In this work, the 3-D honeycomb-like FeCo/C nanocomposites were synthesized through the carbon thermal reduction under an inert atmosphere. The enhanced microwave absorption properties of the composites were mainly attributed to the unique three dimensional structure of the FeCo/C nanocomposites, abundant interfaces and junctions, and the appropriate impedance matching. The Cole-Cole semicircles proved the sufficient dielectric relaxation process. The sample calcinated at 600°C for 4h showed the best microwave absorption properties...
July 31, 2017: Journal of Colloid and Interface Science
Stefan Cwik, Sebastian M J Beer, Stefanie Hoffmann, Michael Krasnopolski, Detlef Rogalla, Hans-Werner Becker, Daniel Peeters, Andreas Ney, Anjana Devi
The application potential of rare earth nitride (REN) materials has been limited due to their high sensitivity to air and moisture leading to facile oxidation upon exposure to ambient conditions. For the growth of device quality films, physical vapor deposition methods, such as molecular beam epitaxy, have been established in the past. In this regard, aluminum nitride (AlN) has been employed as a capping layer to protect the functional gadolinium nitride (GdN) from interaction with the atmosphere. In addition, an AlN buffer was employed between a silicon substrate and GdN serving as a seeding layer for epitaxial growth...
August 16, 2017: ACS Applied Materials & Interfaces
Xiaohui Guo, Min Zhang, Jing Zheng, Jingli Xu, Tasawar Hayat, Njud S Alharbi, Baojuan Xi, Shenglin Xiong
In this paper, an extended Stöber method has been developed to fabricate a Ni(2+)-polydopamine (PDA) complex coated on Co3[Co(CN)6]2@SiO2 composites. After one-step carbonization involving the heat treatment of a Prussian blue analogue (PBA) of Co3[Co(CN)6]2 cores and the PDA-Ni(2+) shell under a nitrogen atmosphere, homogeneous Co@SiO2@C/Ni submicrorattles were synthesized. Notably, the silica interlayer played a vital role in the formation of such Co@SiO2@C/Ni submicrorattle structures. Without the protection of SiO2, Co-Ni@C composites were obtained instead and aggregated seriously due to sintering at high temperature...
August 7, 2017: Dalton Transactions: An International Journal of Inorganic Chemistry
David H Brooks, Deborah Baker, Lidia van Driel-Gesztelyi, Harry P Warren
The elemental composition in the coronae of low-activity solar-like stars appears to be related to fundamental stellar properties such as rotation, surface gravity, and spectral type. Here we use full-Sun observations from the Solar Dynamics Observatory, to show that when the Sun is observed as a star, the variation of coronal composition is highly correlated with a proxy for solar activity, the F10.7 cm radio flux, and therefore with the solar cycle phase. Similar cyclic variations should therefore be detectable spectroscopically in X-ray observations of solar analogs...
August 3, 2017: Nature Communications
Sonia Abreu, Audrey Solgadi, Pierre Chaminade
One important challenge in lipid class analysis is to develop a method suitable or, at least adaptable, for a vast diversity of samples. In the current study, an improved normal-phase liquid chromatography (NPLC) method allowed analyzing the lipid classes present in mammalian, vegetable as well as microorganism (yeast and bacteria) lipid samples. The method effectively separated 30 lipid classes or subclasses with a special focus on medium polarity lipids. The separation was carried out with bare silica stationary phase and was coupled to evaporative light scattering detection (ELSD), charged aerosol detection (Corona-CAD(®)) and mass spectrometry...
July 24, 2017: Journal of Chromatography. A
Qian Yu, Ting Zhang, Xiaoxiao Ma, Ronghua Kang, Jan Mulder, Thorjørn Larssen, Lei Duan
Following Europe and North America, East Asia has become a global hotspot of acid deposition, with very high deposition of both sulfur (S) and nitrogen (N) occurring in large areas in southwest and southeast China. Great efforts have been made in reducing national emission of sulfur dioxide (SO2) since 2006 in China. However, the total emission of nitrogen oxides (NOx) continued to increase until 2011. In order to evaluate the effects of SO2 and NOx emission abatement on acid deposition and acidification of soil and water, we monitored the chemical composition of throughfall, soil water, and stream water from 2001 to 2013 in a small, forested catchment near Chongqing city in Southwestern China...
August 3, 2017: Environmental Science & Technology
Claudio Badini, Silvia M Deambrosis, Elisa Padovano, Monica Fabrizio, Oxana Ostrovskaya, Enrico Miorin, Giuseppe C D'Amico, Francesco Montagner, Sara Biamino, Valentina Zin
A High Power Impulse Magnetron Sputtering (HiPIMS) method for depositing TiAlN environmental barrier coatings on the surface of Ti-48Al-2Cr-2Nb alloy was developed in view of their exploitation in turbine engines. Three differently engineered TiAlN films were processed and their performance compared. Bare intermetallic alloy coupons and coated specimens were submitted to thermal cycling under oxidizing atmosphere up to 850 °C or 950 °C, at high heating and cooling rates. For this purpose, a burner rig able to simulate the operating conditions of the different stages of turbine engines was used...
November 25, 2016: Materials
Taro Shimonosono, Hikari Imada, Hikaru Maeda, Yoshihiro Hirata
The gas permeability of α-alumina, yttria-stabilized zirconia (YSZ), and silicon carbide porous ceramics toward H₂, CO₂, and H₂-CO₂ mixtures were investigated at room temperature. The permeation of H₂ and CO₂ single gases occurred above a critical pressure gradient, which was smaller for H₂ gas than for CO₂ gas. When the Knudsen number (λ/r ratio, λ: molecular mean free path, r: pore radius) of a single gas was larger than unity, Knudsen flow became the dominant gas transportation process...
November 16, 2016: Materials
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