FTIR product study of the Cl-initiated oxidation products of CFC replacements: (/)-1,2,3,3,3-pentafluoropropene and hexafluoroisobutylene.

A product study of the reactions of (/)-1,2,3,3,3-pentafluoropropene ((/)-CFCF[double bond, length as m-dash]CHF) and hexafluoroisobutylene ((CF)C[double bond, length as m-dash]CH) initiated by Cl atoms were developed at 298 ± 2 K and atmospheric pressure. The experiments were carried out in a 1080 L quartz-glass environmental chamber coupled FTIR spectroscopy to monitor the reactants and products. The main products observed and their yields were as follows: CFC(O)F (106 ± 9)% with HC(O)F (100 ± 8)% as a co-product for (/)-CFCF[double bond, length as m-dash]CHF, and CFC(O)CF (94 ± 5)% with HC(O)Cl (90 ± 7)% as a co-product for (CF)C[double bond, length as m-dash]CH.

Degradation mechanism of 2-fluoropropene by Cl atoms: experimental and theoretical products distribution studies.

The gas-phase reaction products of 2-fluoropropene (2FP) with Cl atoms have been determined for the first time at 298 K and atmospheric pressure using a 1080 L quartz-glass photoreactor coupled with FTIR spectroscopy to monitor reactants and products. Acetyl fluoride and formyl chloride were observed as the main products with yields of (106 ± 10)% and (100 ± 11)%, respectively. Electronic structure calculations of reactants, intermediates, products and transition states on a detailed mechanism of the reaction were performed by DFT procedures (BMK, M06, M062X/D3), as well as accurate composite methods on both the addition and abstraction reaction channels.

Preparing Distributed Computing Operations for the HL-LHC Era With Operational Intelligence.

As a joint effort from various communities involved in the Worldwide LHC Computing Grid, the Operational Intelligence project aims at increasing the level of automation in computing operations and reducing human interventions. The distributed computing systems currently deployed by the LHC experiments have proven to be mature and capable of meeting the experimental goals, by allowing timely delivery of scientific results. However, a substantial number of interventions from software developers, shifters, and operational teams is needed to efficiently manage such heterogenous infrastructures.

Influence of Different Alloying Strategies on the Mechanical Behavior of Tool Steel Produced by Laser-Powder Bed Fusion.

Additive manufacturing is a high-potential technique that allows the production of components with almost no limitation in complexity. However, one of the main factors that still limits the laser-based additive manufacturing is a lack of processable alloys such as carbon martensitic hardenable tool steels, which are rarely investigated due to their susceptibility to cold cracking. Therefore, this study aimed to expand the variety of steels for laser powder bed fusion (L-PBF) by investigating an alternative alloying strategy for hot work tool steel powder.

Product distribution and mechanism of the OH initiated tropospheric degradation of three CFC replacement candidates: CHCF[double bond, length as m-dash]CH, (CF)C[double bond, length as m-dash]CH and (/)-CFCF[double bond, length as m-dash]CHF.

The OH radical initiated photodegradation of 2-fluoropropene (CHCF[double bond, length as m-dash]CH), 3,3,3-trifluoro-2-(tri-fluoromethyl)propene ((CF)C[double bond, length as m-dash]CH) and (/)-1,2,3,3,3-pentafluoropropene ((/)-CFCF[double bond, length as m-dash]CHF) has been investigated for the first time using a 1080 L quartz-glass environmental chamber at 298 ± 2 K and atmospheric pressure of synthetic air coupled with FTIR spectroscopy to monitor reactants and products. The major products observed in the OH reaction were CHC(O)F (98 ± 5)% together with HC(O)H (89 ± 7)% as a co-product, CFC(O)F (103 ± 8)% together with HC(O)F (96 ± 7)% as a co-product and CFC(O)CF (91 ± 8)% together with HC(O)H (98 ± 12)% as a co-product from the C-C bond cleavage channel of the intermediate hydroxyalkoxy radical, formed by addition of OH to the terminal carbon of the double bond which is designated C of 2-fluoropropene, (/)-1,2,3,3,3-pentafluoropropene and 3,3,3-trifluoro-2-(tri-fluoromethyl)propene, respectively. The present results are compared with previous studies for the reaction of OH with the separate isomers () and () of 1,2,3,3,3-pentafluoropropene.

Atmospheric sink of β-ocimene and camphene initiated by Cl atoms: kinetics and products at NO free-air.

Rate coefficients for the gas-phase reactions of Cl atoms with β-ocimene and camphene were determined to be (in units of 10 cm per molecule per s) 5.5 ± 0.7 and 3.

Role of Depression and Social Isolation at Time of Waitlisting for Survival 8 Years After Heart Transplantation.

Background: We evaluated depression and social isolation assessed at time of waitlisting as predictors of survival in heart transplant (HTx) recipients.

Methods And Results: Between 2005 and 2006, 318 adult HTx candidates were enrolled in the Waiting for a New Heart Study, and 164 received transplantation. Patients were followed until February 2013.

Slipping on pedestrian surfaces: methods for measuring and evaluating the slip resistance.

Tripping, slipping and falling accidents are among the types of accident with a high incidence. This article describes the requirements concerning slip resistance, as well as the state of the art of slip resistance measurement standards in the European Community and the USA. The article also describes how risk assessment can be performed in the field.

Kinetic study of gas-phase reactions of OH and NO3 radicals and O3 with iso-butyl and tert-butyl vinyl ethers.

Using a relative rate technique, kinetic studies on the gas-phase reactions of OH radicals, ozone, and NO(3) radicals with iso-butyl vinyl ether (iBVE) and tert-butyl vinyl ether (tBVE) have been performed in a 405 L Duran glass chamber at (298 ± 3) K and atmospheric pressure (750 ± 10 Torr) in synthetic air using in situ FTIR spectroscopy to monitor the reactants. The following rate coefficients (in units of cm(3) molecule(-1) s(-1)) have been obtained: (1.08 ± 0.

Atmospheric oxidation of vinyl and allyl acetate: product distribution and mechanisms of the OH-initiated degradation in the presence and absence of NO(x).

The products formed from the reactions of OH radicals with vinyl acetate and allyl acetate have been studied in a 1080 L quartz-glass chamber in the presence and absence of NO(x) using in situ FTIR spectroscopy to monitor the reactant decay and product formation. The yields of the primary products formed in the reaction of OH with vinyl acetate were: formic acetic anhydride (84 ± 11)%; acetic acid (18 ± 3)% and formaldehyde (99 ± 15)% in the presence of NO(x) and formic acetic anhydride (28 ± 5)%; acetic acid (87 ± 12)% and formaldehyde (52 ± 8)% in the absence of NO(x). For the reaction of OH with allyl acetate the yields of the identified products were: acetoxyacetaldehyde (96 ± 15)% and formaldehyde (90 ± 12)% in the presence of NO(x) and acetoxyacetaldehyde (26 ± 4)% and formaldehyde (12 ± 3)% in the absence of NO(x).

Ab initio spin-orbit configuration interaction calculations for high-lying states of the HeNe quasimolecule.

Multireference configuration interaction (MRD-CI) calculations are reported for a large series of electronic states of the HeNe quasimolecule up to 170000 cm(-1) excitation energy, including those that dissociate to the 3S1 and 2 1S0 excited states of the He atom. Spin-orbit coupling is included through the use of relativistic effective core potentials (RECPs). Good agreement is obtained with experimental spectroscopic data for the respective atomic levels, although there is a tendency to systematically underestimate the energies of the Ne atom by 1000-1500 cm(-1) because of differences in the correlation effects associated with its ground and Rydberg excited states.

Positron binding energies for alkali hydrides.

Ab initio multireference single- and double-excitation configuration interaction (MRD-CI) calculations are carried out to study the interactions of positrons with the members of the alkali hydride class of molecules. A new computer program has been constructed for this purpose that makes use of the Table-Direct-CI method for construction of the required Hamiltonian matrixes and electronic/positronic wave functions. The calculations indicate that the binding energy (positron affinity PA) of a single positron to these systems increases by an increment of 0.

Biotechnology and molecular biology of the alpha-glucosidase inhibitor acarbose.

The alpha-glucosidase inhibitor acarbose, O-[4,6-dideoxy-4[1 s-(1,4,6/5)-4,5,6-trihydroxy-3-hydroxymethyl-2-cyclohexen-1-yl]-amino-alpha-D-glucopyranosyl]-(1-->4)- O-alpha-D-glucopyranosyl-(1-->4)-D-glucopyranose, is produced in large-scale fermentation by the use of strains derived from Actinoplanes sp. SE50. It has been used since 1990 in many countries in the therapy of diabetes type II, in order to enable patients to better control blood sugar contents while living with starch-containing diets.

Use of exchange maximization to generate starting vectors for self-consistent field calculations on metal cluster/adsorbate systems.

Localized molecular orbitals (LMOs) derived from exchange maximization with respect to all atom-centered basis functions in the basis set are shown to generate a good starting electronic field for self-consistent field calculations on extended systems such as metal clusters, for which well-defined chemical bonds are not present. Examples studied are a cluster of 20 Ni atoms and the Pt(97)CO, Ag(43)/H(3)CNON, Ag(91)/H(2)CO, and vinylidene/Ni metal cluster plus adsorbate systems. It is also shown that improved starting vectors can be obtained by remixing a subset of the LMOs with the largest exchange eigenvalues through diagonalization of the Fock matrix computed with a null electronic field.