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Vitor Sousa, Celia Dias-Ferreira, João M Vaz, Inês Meireles
Extensive research has been carried out on waste collection costs mainly to differentiate costs of distinct waste streams and spatial optimization of waste collection services (e.g. routes, number, and location of waste facilities). However, waste collection managers also face the challenge of optimizing assets in time, for instance deciding when to replace and how to maintain, or which technological solution to adopt. These issues require a more detailed knowledge about the waste collection services' cost breakdown structure...
May 1, 2018: Waste Management & Research
Zhe Bai, Xinjian Cui, Xinfeng Wang, Huijun Xie, Bing Chen
The estimates of radiative forcing of black carbon (BC) remain great uncertainty, largely due to variations in the absorption enhancement of BC by mixing with organic and inorganic coatings in ambient aerosols. We applied a two-step solvent treatment method that experimentally removed coating materials in aerosol samples to determine the BC absorption enhancement. Aerosol samples were collected at Mt. Tai and a severely polluted urban area (Jinan) in North China Plain (NCP). The mass absorption cross-section (MAC) of BC aerosols was determined before and after the coating removal...
April 21, 2018: Science of the Total Environment
Yi-Chou Tsai, N V Satyachand Harisomayajula, Bo-Han Wu, Duan-Yen Lu, Ting-Shen Kuo, I-Chia Chen
Synthesis and characterization of three hexa-copper(I) extended metal atom chains (EMACs) and two dodecacopper(I) aggregates assembled by two hexadentate bis(pyridylamido)amidinate-supported hexacopper(I) string complexes (monomers) via the ligand-unsupported cuprophilicity are described. The hexa-copper(I) EMACs show distinct coordination chemistry upon coordination of THF molecules. One is ligated by one THF molecule at the Cu3, while one is coordinated by two THF molecules at the Cu2 and Cu5. These Cu-THF bonds are so weak that THF ligands readily dissociate upon dissolution in organic solvents to give dodecacopper(I) aggregates...
April 28, 2018: Angewandte Chemie
Anandi Srinivasan, Miguel Cortijo, Vladimir Bulicanu, Ahmad Naim, Rodolphe Clérac, Philippe Sainctavit, Andrei Rogalev, Fabrice Wilhelm, Patrick Rosa, Elizabeth A Hillard
A simple procedure based on anion exchange was employed for the enantiomeric resolution of the extended metal atom chain (EMAC) [Co3 (dpa)4 (MeCN)2 ]2+ . Use of the chiral salt (NBu4 )2 [As2 (tartrate)2 ], (Λ- 1 or Δ- 1 ), resulted in the selective crystallization of the EMAC enantiomers as [Δ-Co3 (dpa)4 (MeCN)2 ](NBu4 )2 [Λ-As2 (tartarte)2 ]2 , (Δ- 2 ) and [Λ-Co3 (dpa)4 (MeCN)2 ](NBu4 )2 [Δ-As2 (tartrate)2 ]2 (Λ- 2 ), respectively, in the P 421 2 space group, whereas a racemic mixture of 1 yielded [Co3 (dpa)4 (MeCN)2 ][As2 (tartrate)2 ]·2MeCN ( rac - 3 ), which crystallized in the C 2/ c space group...
February 7, 2018: Chemical Science
Orestes Rivada-Wheelaghan, Sandra L Aristizábal, Joaquín López-Serrano, Robert R Fayzullin, Julia R Khusnutdinova
Reversible stepwise chain growth in linear CuI assemblies can be achieved by using the dynamic, unsymmetric naphthyridinone-based ligand scaffolds L1 and L2. With the same ligand scaffolds, the length of the linear copper chain can be varied from two to three and four copper atoms, and the nuclearity of the complex is easily controlled by the stepwise addition of a CuI precursor to gradually increase the chain length, or by the reductive removal of Cu atoms to decrease the chain length. This represents a rare example of a stepwise controlled chain growth in extended metal atom chains (EMACs)...
December 18, 2017: Angewandte Chemie
M Spivak, V Arcisauskaite, X López, C de Graaf
Recently published static DFT and CASSCF/CASPT2 calculations depicted extremely flat Potential Energy Surfaces (PESs) for the Cr-Cr flexibility of Cr3 (dpa)4 X2 (X = NCS- , CN- , NO3 - ) extended metal atom chains (EMACs) (M. Spivak, et al., Dalton Trans., 2017, 46, 6202). We herein explore the thermal and crystal packing effects on the structure of EMACs using ab initio molecular dynamics (MD). Car-Parrinello DFT-based simulations of the isolated molecules show that thermal energy favors asymmetric arrangements of the Cr3 chain due, in part, to the bending of the axial ligands (X) and the increased X-Cr distance, both of which weaken X → Cr σ-donation...
November 14, 2017: Dalton Transactions: An International Journal of Inorganic Chemistry
Nayar Musfera Abdul Masjeed, Siddhi Gaurish Sinai Khandeparkar, Avinash R Joshi, Maithili Mandar Kulkarni, Nidhi Pandya
INTRODUCTION: Endometrial carcinoma is the second most common gynecologic malignancy in the developing countries. Endometrial Hyperplasia (EH) is a precursor to Endometrioid Adenocarcinoma (EMAC). A 23% of Atypical Hyperplasias (AEH) progress to EMAC. AIM: This study was undertaken to analyse ER, PR, p53 and Ki67 in EH and endometrial carcinomas and attempt correlation with clinical and histopathological findings. MATERIALS AND METHODS: The present study was conducted over a period of seven years...
August 2017: Journal of Clinical and Diagnostic Research: JCDR
M Spivak, V Arcisauskaite, X López, J E McGrady, C de Graaf
Density functional theory, Complete Active Space Self-Consistent Field (CASSCF) and perturbation theory (CASPT2) methodologies have been used to explore the electronic structure of a series of trichromium Extended Metal Atom Chains (EMACS) with different capping ligands. The study is motivated by the very different structural properties of these systems observed in X-ray experiments: the CN- -capped example has a symmetric Cr3 unit while for the NO3 - -capped analogue the same unit has two very different Cr-Cr bond lengths...
May 16, 2017: Dalton Transactions: An International Journal of Inorganic Chemistry
Manabu Shiraiwa, Ying Li, Alexandra P Tsimpidi, Vlassis A Karydis, Thomas Berkemeier, Spyros N Pandis, Jos Lelieveld, Thomas Koop, Ulrich Pöschl
Secondary organic aerosols (SOA) are a large source of uncertainty in our current understanding of climate change and air pollution. The phase state of SOA is important for quantifying their effects on climate and air quality, but its global distribution is poorly characterized. We developed a method to estimate glass transition temperatures based on the molar mass and molecular O:C ratio of SOA components, and we used the global chemistry climate model EMAC with the organic aerosol module ORACLE to predict the phase state of atmospheric SOA...
April 21, 2017: Nature Communications
Benjamin Schweitzer, Chantal Daniel, Christophe Gourlaouen
A topological analysis based on density functional electronic and spin densities of the bonding characteristics in a series of Fe, Ru, Os, Tc and Rh dimers and trimers bridged, respectively, by μ-1,8-naphthyridine (nap) and μ-2,2'-dipyridylamine (dpa) is presented. By this simple qualitative analysis, we were able to determine the electronic ground state and correlated bonding order for a number of complexes potentially involved in extended metal atom chains (EMAC). Furthermore, we showed in the Ru dimer that it was possible to control the spin state simply by changing the bonded counter-anion...
May 2017: Journal of Molecular Modeling
Po-Jung Chen, Marc Sigrist, Er-Chien Horng, Geng-Min Lin, Gene-Hsiang Lee, Chun-Hsien Chen, Shie-Ming Peng
Striding to extend the length of metal-atom strings, oligo-α-pyridylamino ligands are modulated with naphthyridyl moieties leading to the undeca-nickel mixed-valence complexes [Ni11 (bnatpya)4 Cl2 ]4+ (1) and [Ni11 (bnatpya)4 Cl2 ]2+ (2). The first single-molecule conductance measurements of a linear undeca-nickel chain were performed.
April 25, 2017: Chemical Communications: Chem Comm
Bing Chen, Zhe Bai, Xinjuan Cui, Jianmin Chen, August Andersson, Örjan Gustafsson
Atmospheric black carbon (BC) is an important pollutant for both air quality and Earth's energy balance. Estimates of BC climate forcing remain highly uncertain, e.g., due to the mixing with non-absorbing components. Non-absorbing aerosols create a coating on BC and may thereby act as a lens which may enhance the light absorption. However, this absorption enhancement is poorly constrained. To this end a two-step solvent dissolution protocol was employed to remove both organic and inorganic coatings, and then investigate their effects on BC light absorption...
February 2017: Environmental Pollution
Heejae Kim, Wilfred Chen
Protein purification using inverse phase transition of elastin-like polypeptide (ELP) domains is a useful alternative to chromatography. Genetic fusions of ELP domains to various proteins have the ability to reversibly transition between soluble monomers and micron-sized aggregates and this has been used to selectively purify many ELP fusions. Affinity domains can enhance this technology by using specific protein binding domains to enable ELP mediated affinity capture (EMAC) of proteins of interest (POI) that have been fused to corresponding affinity ligands...
September 20, 2016: Journal of Biotechnology
Paweł Szarek, Wojciech Wegner, Wojciech Grochala
Theoretical calculations for the first tri-iron-based extended metal atom chain (EMAC) molecule are reported. The studied triple-high-spin (S = 6) complex exhibits ferromagnetic ordering (according to Ising and spin-projection approximations), which renders it unique among all previously prepared and theoretically calculated EMAC compounds. This ordering originates from the prevailing ferromagnetic nearest-neighbor interactions, while the magnetic superexchange between terminal Fe(2+) sites is weaker and antiferromagnetic...
March 2016: Journal of Molecular Modeling
Xinjuan Cui, Xinfeng Wang, Lingxiao Yang, Bing Chen, Jianmin Chen, August Andersson, Örjan Gustafsson
The radiative absorption enhancement of ambient black carbon (BC), by light-refractive coatings of atmospheric aerosols, constitutes a large uncertainty in estimates of climate forcing. The direct measurements of radiative absorption enhancement require the experimentally-removing the coating materials in ambient BC-containing aerosols, which remains a challenge. Here, the absorption enhancement of the BC core by non-absorbing aerosol coatings was quantified using a two-step removal of both inorganic and organic matter coatings of ambient aerosols...
May 1, 2016: Science of the Total Environment
Vivek Dhand, J Sarada Prasad, Venkateswer M Rao, Sujith Kalluri, Pawan Kumar Jain, B Sreedhar
Carbon nanofibers (CNF) have been synthesized under partial combustion conditions in a flame reactor using different mixtures of hydrocarbon gases in the presence and absence of precursors. The hydrogen (H2) adsorption studies have been carried out using a high pressure Sievert's apparatus maintained at a constant temperature (24 degrees C). The flame synthesized CNFs showed high degree of H2 adsorption capacities at 100 atm pressure. The highest H2 capacities recorded have been 4.1 wt% [for CNF produced by liquefied petroleum gas (LPG)-Air (E-17)], 3...
January 2015: Journal of Nanoscience and Nanotechnology
P Szarek, W Grochala
The relationship between equatorial ligands structures and magnetic response of [Ni3]6+ extended metal atom chain core has been investigated. The distances between metal ions in Ni metal strings are largely predefined by framework provided through equatorial ligands. The equatorial ligands thus have primary influence on the magnitude of magnetic coupling between terminal high spin centers. Since the σ channel has greatest contribution to J, the variations in Ni–Ni bond lengths have immediate and strong effect on magnetic properties...
September 3, 2015: Journal of Physical Chemistry. A
C Brühl, J Lelieveld, H Tost, M Höpfner, N Glatthor
Multiyear simulations with the atmospheric chemistry general circulation model EMAC with a microphysical modal aerosol module at high vertical resolution demonstrate that the sulfur gases COS and SO2, the latter from low-latitude and midlatitude volcanic eruptions, predominantly control the formation of stratospheric aerosol. Marine dimethyl sulfide (DMS) and other SO2 sources, including strong anthropogenic emissions in China, are found to play a minor role except in the lowermost stratosphere. Estimates of volcanic SO2 emissions are based on satellite observations using Total Ozone Mapping Spectrometer and Ozone Monitoring Instrument for total injected mass and Michelson Interferometer for Passive Atmospheric Sounding (MIPAS) on Envisat or Stratospheric Aerosol and Gases Experiment for the spatial distribution...
March 16, 2015: Journal of Geophysical Research. Atmospheres: JGR
Ivan A Popov, Boris B Averkiev, Alyona A Starikova, Alexander I Boldyrev, Ruslan M Minyaev, Vladimir I Minkin
Theoretical investigations to evaluate the viability of extended nonmetal atom chains on the basis of molecular models with the general formula Mn F4n+2 (M=S and Se) and corresponding solid-state systems exhibiting direct SS or SeSe bonding were performed. The proposed high-symmetry molecules were found to be minima on the potential energy surface for all Sn F4n+2 systems studied (n=2-9) and for selenium analogues up to n=6. Phonon calculations of periodic structures confirmed the dynamic stability of the -(SF4 -SF4 )∞ - chain, whereas the analogous -(SeF4 -SeF4 )∞ - chain was found to have a number of imaginary phonon frequencies...
January 26, 2015: Angewandte Chemie
Liyi Li, Xueying Zhao, Ching-Ping Wong
In this work, a novel wet silicon (Si) etching method, electric bias-attenuated metal-assisted chemical etching (EMaCE), is demonstrated to be readily available for three-dimensional (3D) electronic integration, microelectromechinal systems, and a broad range of 3D electronic components with low cost. On the basis of the traditional metal-assisted chemical etching process, an electric bias was applied to the Si substrate in EMaCE. The 3D geometry of the etching profile was effectively controlled by the bias in a real-time manner...
October 8, 2014: ACS Applied Materials & Interfaces
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