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Atmospheric composition

Goli Nagaraju, Sung Min Cha, Jae Su Yu
Three-dimensional hierarchical honeycomb-like activated porous carbon pillared ultrathin Ni(OH)2 nanosheets (Ni(OH)2 NSs@HAPC) for use as supercapacitor materials were facilely synthesized. With an aid of pine cone flowers as a biomass source, HAPC conducting scaffolds were prepared by the alkali treatment and pyrolysis methods under an inert gas atmosphere. Subsequently, the Ni(OH)2 NSs were synthesized evenly on the surface of HAPC via a solvothermal method. The resulting HAPC and Ni(OH)2 NSs@HAPC composite materials offered free pathways for effective diffusion of electrolyte ions and fast transportation of electrons when employed as an electrode material...
March 24, 2017: Scientific Reports
Lukasz Szymanski, Zbigniew Kolacinski, Slawomir Wiak, Grzegorz Raniszewski, Lukasz Pietrzak
In this paper, a novel approach to the synthesis of the carbon nanotubes (CNTs) in reactors operating at atmospheric pressure is presented. Based on the literature and our own research results, the most effective methods of CNT synthesis are investigated. Then, careful selection of reagents for the synthesis process is shown. Thanks to the performed calculations, an optimum composition of gases and the temperature for successful CNT synthesis in the CVD (chemical vapor deposition) process can be chosen. The results, having practical significance, may lead to an improvement of nanomaterials synthesis technology...
February 18, 2017: Nanomaterials
Sarah L Newberry, Ulrich E Prechsl, Matthew Pace, Ansgar Kahmen
Cryogenic vacuum extraction is the well-established method of extracting water from soil for isotopic analyses of waters moving through the soil-plant-atmosphere continuum. We investigate if soils can alter the isotopic composition of water through isotope memory effects, and determined which mechanisms are responsible for it. Soils with differing physicochemical properties were re-wetted with reference water and subsequently extracted by cryogenic water distillation. Results suggest some reference waters bind tightly to the soil and not all of this tightly bound water is removed during cryogenic vacuum extraction...
March 23, 2017: Isotopes in Environmental and Health Studies
Ju Ying Li, Qing Song Mei
TiAl₃ and TiN composite nanoparticles were continuously synthesized from Ti-48Al master alloy by hydrogen plasma-metal reaction in a N₂, H₂ and Ar atmosphere. The phase, morphology, and size of the nanoparticles were studied by X-ray diffraction (XRD) and transmission electronic microscopy (TEM). X-ray photoelectron spectroscopy (XPS) and evolved gas analysis (EGA) were used to analyze the surface phase constitution and oxygen content of the nanoparticles. The as-synthesized nanopowders were mainly composed of nearly spherical TiAl₃ and tetragonal TiN phases, with a mean diameter of ~42 nm and mass fractions of 49...
June 1, 2016: Nanomaterials
Alex Plumridge, Steve P Meisburger, Kurt Andresen, Lois Pollack
Single-stranded DNA (ssDNA) is notable for its interactions with ssDNA binding proteins (SSBs) during fundamentally important biological processes including DNA repair and replication. Previous work has begun to characterize the conformational and electrostatic properties of ssDNA in association with SSBs. However, the conformational distributions of free ssDNA have been difficult to determine. To capture the vast array of ssDNA conformations in solution, we pair small angle X-ray scattering with novel ensemble fitting methods, obtaining key parameters such as the size, shape and stacking character of strands with different sequences...
February 25, 2017: Nucleic Acids Research
ChuanYang Cai, JingYa Li, Di Wu, XiLong Wang, Daniel C W Tsang, XiangDong Li, JianTeng Sun, LiZhong Zhu, HuiZhong Shen, Shu Tao, WenXin Liu
243 surface soil samples were collected from the Yangtze River Delta (YRD) region, and the concentration distributions and compositional profiles of 27 parent PAHs (PPAHs), nitro- and oxy-derivatives (NPAHs and OPAHs), respectively, and health risk of 16 PPAHs were determined. Atmospheric samples were collected at two sites with high topsoil concentrations of PAHs to assist in identifying the emission sources of PPAHs. The total concentrations of PPAHs, NPAHs and OPAHs fell in the ranges of 21.0-3563.2 ng/g, 0...
March 16, 2017: Chemosphere
Cecilia Sorbello, Petra Gross, Cristian A Strassert, Matías Jobbágy, Beatriz C Barja
A family of Er(III) and Er(III) -Yb(III) based nanophosphors, hosted in monophasic oxidic Ce(IV) -Gd(III) binary solid solutions, was prepared. The samples were formulated with a constant Er(III) content as the activator, with the eventual addition of Yb(III) as a sensitizer. The amorphous Ce0.94-x Gdx Er0.06 (OH)CO3 ⋅H2 O and Ce0.94-x Gdx Er0.05 Yb0.01 (OH)CO3 ⋅H2 O precursors were prepared by following the urea method to obtain monodispersed spheres of tunable size ranging from 30 to 450 nm. After being decomposed at 1273 K under an atmosphere of air, the precursors of 200 nm in diameter evolved into monophasic polycrystalline particles preserving the parent shape and size...
March 23, 2017: Chemphyschem: a European Journal of Chemical Physics and Physical Chemistry
Tobias Spranger, Dominik van Pinxteren, Hartmut Herrmann
Organic carbon in atmospheric particles comprises a large fraction of chromatographically unresolved compounds, often referred to as humic-like substances (HULIS), which influence particle properties and impacts on climate, human health and ecosystems. To better understand its composition, a two-dimensional (2D) offline method combining size-exclusion (SEC) and reversed-phase liquid chromatography (RP-HPLC) using a new spiked gradient profile is presented. It separates HULIS into 55 fractions of different size and polarity, with estimated ranges of molecular weight and octanol/water partitioning coefficient (log P) from 160-900 g/mol and 0...
March 23, 2017: Environmental Science & Technology
E Łokas, R Anczkiewicz, R Kierepko, J W Mietelski
Although the polar regions have not been industrialised, numerous contaminants originating from human activity are detectable in the Arctic environment. This study reports evidence of (240)Pu/(239)Pu atomic ratios in the tundra and initial soils from different parts of west and central Spitsbergen and recognizes possible environmental inputs of non-global fallout Pu. The average atomic ratio of (240)Pu/(239)Pu equal to 0.179 (ranging between 0.129 and 0.201) in tundra soils are comparable to the characteristic ratio for global fallout (0...
March 18, 2017: Chemosphere
Sukrit Ranjan, Dimitar D Sasselov
The UV environment is a key boundary condition to abiogenesis. However, considerable uncertainty exists as to planetary conditions and hence surface UV at abiogenesis. Here, we present two-stream multilayer clear-sky calculations of the UV surface radiance on Earth at 3.9 Ga to constrain the UV surface fluence as a function of albedo, solar zenith angle (SZA), and atmospheric composition. Variation in albedo and latitude (through SZA) can affect maximum photoreaction rates by a factor of >10.4; for the same atmosphere, photoreactions can proceed an order of magnitude faster at the equator of a snowball Earth than at the poles of a warmer world...
March 2017: Astrobiology
Yuan-Qing Li, Pei Huang, Wei-Bin Zhu, Shao-Yun Fu, Ning Hu, Kin Liao
In this work, a wire-shaped flexible strain sensor was fabricated by encapsulating conductive carbon thread (CT) with polydimethylsiloxane (PDMS) elastomer. The key strain sensitive material, CT, was prepared by pyrolysing cotton thread in N2 atmosphere. The CT/PDMS composite wire shows a typical piezo-resistive behavior with high strain sensitivity. The gauge factors (GF) calculated at low strain of 0-4% and high strain of 8-10% are 8.7 and 18.5, respectively, which are much higher than that of the traditional metallic strain sensor (GF around 2)...
March 21, 2017: Scientific Reports
Eva-Maria Köck, Michaela Kogler, Thomas Götsch, Lukas Schlicker, Maged F Bekheet, Andrew Doran, Aleksander Gurlo, Bernhard Klötzer, Benedikt Petermüller, Daniel Schildhammer, Nevzat Yigit, Simon Penner
The surface chemical properties of undoped tetragonal ZrO2 and the gas-phase dependence of the tetragonal-to-monoclinic transformation are studied using a tetragonal ZrO2 polymorph synthesized via a sol-gel method from an alkoxide precursor. The obtained phase-pure tetragonal ZrO2 is defective and strongly hydroxylated with pronounced Lewis acidic and Brønsted basic surface sites. Combined in situ FT-infrared and electrochemical impedance measurements reveal effective blocking of coordinatively unsaturated sites by both CO and CO2, as well as low conductivity...
March 20, 2017: Dalton Transactions: An International Journal of Inorganic Chemistry
Peng Mei, Malay Pramanik, Jaewoo Lee, Toshiaki Takei, Yusuke Ide, Md Shahriar A Hossain, Jung Ho Kim, Yusuke Yamauchi
Recently, a layered material with composition Li1+xV1-xO2 has been discovered as a promising alternative anode material to graphite due to its high volumetric capacity and low operation potential. Herein, we demonstrate a mild and cost-effective synthetic methodology to construct a novel nanoporous anode material (P-LVO@C), comprising Li1+xV1-xO2 nanocrystals embedded in a porous carbon matrix. The thermal decomposition of organic materials, including a triblock copolymer (P123) and citric acid, in a N2 atmosphere is the source of the nanoporous carbon in the porous composite material, while citric acid also plays a crucial role in maintaining the reductive environment of the synthetic medium...
March 20, 2017: Physical Chemistry Chemical Physics: PCCP
Meikang Han, Xiaowei Yin, Zexin Hou, Changqing Song, Xinliang Li, Litong Zhang, Laifei Cheng
Three-dimensional (3D) flexible foams consisting of reduced graphene oxides (rGO) and in-situ grown SiC nanowires (NWs) were prepared using freeze-drying and carbothermal reduction process. By means of incorporating SiC nanowires into rGO foams, both the thermostability and electromagnetic absorption of the composites were improved. It was demonstrated that rGO/SiC NWs foams were thermostable beyond ~630 °C (90% weight retention in air atmosphere). As expected, rGO/SiC NWs foams in the poly (dimethylsiloxane) matrix achieved effective absorption in the entire X-band (8...
March 20, 2017: ACS Applied Materials & Interfaces
Rongfu Li, Xiaohong Ruan, Ying Bai, Tianhai Ma, Congqiang Liu
Straw return is becoming a routine practice in disposing of crop residues worldwide. However, the potential effect of such operation on the chemistry of local groundwater is not well documented. Here, shallow groundwater in an area where wheat-maize straw return is practiced was analyzed, and the seasonal changes in the nitrate concentration and the isotope compositions of NO3(-) and H2O were determined along two flow paths. Measured δD and δ(18)O in waters indicated that the groundwater was mainly recharged by atmospheric precipitation, while measured δ(15)N and δ(18)O in nitrate suggested that the sources for groundwater NO3(-) included urea fertilizer, soil nitrogen, and sewage/manure...
March 14, 2017: Science of the Total Environment
N G Semaltianos, R Chassagnon, V Moutarlier, V Blondeau-Patissier, M Assoul, G Monteil
Laser irradiation of a mixture of single-element micro/nanomaterials may lead to their alloying and fabrication of multi-element structures. In addition to the laser induced alloying of particulates in the form of micro/nanopowders in ambient atmosphere (which forms the basis of the field of additive manufacturing technology), another interesting problem is the laser-induced alloying of a mixture of single-element nanoparticles in liquids since this process may lead to the direct fabrication of alloyed-nanoparticle colloidal solutions...
April 18, 2017: Nanotechnology
Rui Li, Haijian Bing, Yanhong Wu, Jun Zhou, Zhongxiang Xiang
The aim of this study is to reveal the effects of regional human activity on trace metal accumulation in remote alpine ecosystems under long-distance atmospheric transport. Trace metals (Cd, Pb, and Zn) in soils of the Mt. Luoji, Southwest China, were investigated along a large altitudinal gradient [2200-3850 m above sea level (a.s.l.)] to elaborate the key factors controlling their distribution by Pb isotopic composition and statistical models. The concentrations of Cd, Pb, and Zn in the surface soils (O and A horizons) were relatively low at the altitudes of 3500-3700 m a...
March 16, 2017: Environmental Geochemistry and Health
Shang-Yang Yu, Hariyanto Gunawan, Shiao-Wen Tsai, Yun-Ju Chen, Tzu-Chen Yen, Jiunn-Woei Liaw
Through the light-driven geometrically oriented attachment (OA) and self-assembly of Au nanorods (NRs) or nanoparticles (NPs), single-crystalline Au nanowires (NWs) were synthesized by the irradiation of a linearly-polarized (LP) laser. The process was conducted in a droplet of Au colloid on a glass irradiated by LP near-infrared (e.g. 1064 nm and 785 nm) laser beam of low power at room temperature and atmospheric pressure, without any additive. The FE-SEM images show that the cross sections of NWs are various: tetragonal, pentagonal or hexagonal...
March 16, 2017: Scientific Reports
L René Corrales, Thomas D Yi, Samantha K Trumbo, David Shalloway, Jonathan I Lunine, David A Usher
The atmosphere of Titan, Saturn's largest moon, exhibits interesting UV- and radiation-driven chemistry between nitrogen and methane, resulting in dipolar, nitrile-containing molecules. The assembly and subsequent solvation of such molecules in the alkane lakes and seas found on the moon's surface are of particular interest for investigating the possibility of prebiotic chemistry in Titan's hydrophobic seas. Here we characterize the solvation of acetonitrile, a product of Titan's atmospheric radiation chemistry tentatively detected on Titan's surface [H...
March 14, 2017: Journal of Chemical Physics
Julia Schmale, Silvia Henning, Bas Henzing, Helmi Keskinen, Karine Sellegri, Jurgita Ovadnevaite, Aikaterini Bougiatioti, Nikos Kalivitis, Iasonas Stavroulas, Anne Jefferson, Minsu Park, Patrick Schlag, Adam Kristensson, Yoko Iwamoto, Kirsty Pringle, Carly Reddington, Pasi Aalto, Mikko Äijälä, Urs Baltensperger, Jakub Bialek, Wolfram Birmili, Nicolas Bukowiecki, Mikael Ehn, Ann Mari Fjæraa, Markus Fiebig, Göran Frank, Roman Fröhlich, Arnoud Frumau, Masaki Furuya, Emanuel Hammer, Liine Heikkinen, Erik Herrmann, Rupert Holzinger, Hiroyuki Hyono, Maria Kanakidou, Astrid Kiendler-Scharr, Kento Kinouchi, Gerard Kos, Markku Kulmala, Nikolaos Mihalopoulos, Ghislain Motos, Athanasios Nenes, Colin O'Dowd, Mikhail Paramonov, Tuukka Petäjä, David Picard, Laurent Poulain, André Stephan Henry Prévôt, Jay Slowik, Andre Sonntag, Erik Swietlicki, Birgitta Svenningsson, Hiroshi Tsurumaru, Alfred Wiedensohler, Cerina Wittbom, John A Ogren, Atsushi Matsuki, Seong Soo Yum, Cathrine Lund Myhre, Ken Carslaw, Frank Stratmann, Martin Gysel
Cloud condensation nuclei (CCN) number concentrations alongside with submicrometer particle number size distributions and particle chemical composition have been measured at atmospheric observatories of the Aerosols, Clouds, and Trace gases Research InfraStructure (ACTRIS) as well as other international sites over multiple years. Here, harmonized data records from 11 observatories are summarized, spanning 98,677 instrument hours for CCN data, 157,880 for particle number size distributions, and 70,817 for chemical composition data...
March 14, 2017: Scientific Data
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