Plasma enhanced vortex fluidic device manipulation of graphene oxide

Open Access Article. This article is licensed under a Creative Commons Attribution 3.0 Unported Licence.A vortex fluid device (VFD) with non-thermal plasma liquid processing within dynamic thin films has been developed. This plasma–liquid microfluidic platform facilitates chemical processing which is demonstrated through the manipulation of the morphology and chemical character of colloidal graphene oxide in water

Differential cross sections for the electron impact excitation of pyrimidine

We report on differential cross section (DCS) measurements for the electron-impact excitation of the electronic states of pyrimidine. The energy range of the present measurements was 15–50 eV with the angular range of the measurements being 10°–90°. All measured DCSs displayed forward-peaked angular distributions, consistent with the relatively large magnitudes for the dipole moment and dipole polarizability of pyrimidine. Excitations to triplet states were found to be particularly important in some energy loss features at the lower incident electron energies. To the best of our knowledge there are no other experimental data or theoretical computations against which we can compare the present results

Experimental and theoretical investigation of the triple differential cross section for electron impact ionization of pyrimidine molecules

Cross-section data for electron impact induced ionization of bio-molecules are important for modelling the deposition of energy within a biological medium and for gaining knowledge of electron driven processes at the molecular level. Triply differential cross sections have been measured for the electron impact ionization of the outer valence 7b2 and 10a1 orbitals of pyrimidine, using the (e, 2e) technique. The measurements have been performed with coplanar asymmetric kinematics, at an incident electron energy of 250 eV and ejected electron energy of 20 eV, for scattered electron angles of −5°, −10°, and −15°. The ejected electron angular range encompasses both the binary and recoil peaks in the triple differential cross section. Corresponding theoretical calculations have been performed using the molecular 3-body distorted wave model and are in reasonably good agreement with the present experiment

Dynamical (e, 2e) studies of tetrahydrofurfuryl alcohol

Cross section data for electron scattering from DNA are important for modelling radiation damage in biological systems. Triply differential cross sections for the electron impact ionization of the highest occupied outer valence orbital of tetrahydrofurfuryl alcohol, which can be considered as an analogue to the deoxyribose backbone molecule in DNA, have been measured using the (e,2e) technique. The measurements have been performed with coplanar asymmetric kinematics at an incident electron energy of 250 eV, an ejected electron energy of 20 eV, and at scattered electron angles of −5°, −10°, and −15°. Experimental results are compared with corresponding theoretical calculations performed using the molecular 3-body distorted wave model. Some important differences are observed between the experiment and calculations

Turbo thin film continuous flow production of biodiesel from fungal biomass

This manuscript version is made available under the CC-BY-NC-ND 4.0 license: http://creativecommons.org/licenses/by-nc-nd/4.0/ which permits use, distribution and reproduction in any medium, provided the original work is properly cited. This author accepted manuscript is made available following 24 month embargo from date of publication (November 2018) in accordance with the publisher’s archiving policyDirect biodiesel production from wet fungal biomass may significantly reduce production costs, but there is a lack of fast and cost-effective processing technology. A novel thin film continuous flow process has been applied to study the effects of its operational parameters on fatty acid (FA) extraction and FA to fatty acid methyl ester (FAME) conversion efficiencies. Single factor experiments evaluated the effects of catalyst concentration and water content of biomass, while factorial experimental designs determined the interactions between catalyst concentration and biomass to methanol ratio, flow rate, and rotational speed. Direct transesterification (DT) of wet Mucor plumbeus biomass at ambient temperature and pressure achieved a FA to FAME conversion efficiency of >90% using 3 wt/v % NaOH concentration, if the water content was ≤50% (w/w). In comparison to existing DT methods, this continuous flow processing technology has an estimated 90–94% reduction in energy consumption, showing promise for up-scaling.Eko K. Sitepu gratefully acknowledges funding through the Australian Award Scholarship. The authors acknowledge funding of the project through the Australian Research Council and the Government of South Australia

Negative ion formation through dissociative electron attachment to the group IV tetrachlorides: Carbon tetrachloride, silicon tetrachloride and germanium tetrachloride

© 2018 Elsevier. This manuscript version is made available under the CC-BY-NC-ND 4.0 license:http://creativecommons.org/licenses/by-nc-nd/4.0/ This author accepted manuscript is made available following 24 month embargo from date of publication (Jan 2018) in accordance with the publisher’s archiving policyThe current contribution constitutes the third and final part of our trilogy of papers on electron attachment reactions of the group IV tetrahalides; XY4 (X = C, Si, Ge and Y = F, Cl, Br). In this context we extend our previous studies on XF4 and XBr4 and report results for electron attachment to the tetrachlorides: CCl4, SiCl4 and GeCl4 in the incident electron energy range from about 0 to 10 eV. At the same time we give a summary of the currently available literature on electron interactions with those latter compounds. Upon electron attachment the formation of Cl−, XCl3−, XCl2− and Cl2− is observed from all the tetrachlorides, and additionally the molecular anion SiCl4− is observed from SiCl4. The main DEA contributions are observed through narrow, threshold peaks (at 0 eV) and we attribute these features to single particle resonances associated with the a1 symmetry LUMOs of those compounds. Contributions from another low-lying resonance, which we assign as a 2T2 shape resonance associated with the t2 symmetry LUMO+1, is also observed in the ion yield curves for all the tetrachlorides. The energy of the peak position of those contributions varies in the range from about 1 to 2 eV, depending on the compound and the fragment formed. In addition to these low energy contributions, higher energy, fairly broad, features are observed for all the tetrachlorides. These contributions exhibit a peak in the energy range between 5 and 8 eV, again depending on the compound and the fragment formed. Further to the experimental data, we report DFT and coupled cluster calculations on the thermochemical thresholds for the individual fragments as well as the respective bond dissociation energies and electron affinities. These calculated values are compared with the experimental appearance energies and literature values, where they are available

The James Webb Space Telescope Mission

Twenty-six years ago a small committee report, building on earlier studies, expounded a compelling and poetic vision for the future of astronomy, calling for an infrared-optimized space telescope with an aperture of at least $4m$. With the support of their governments in the US, Europe, and Canada, 20,000 people realized that vision as the $6.5m$ James Webb Space Telescope. A generation of astronomers will celebrate their accomplishments for the life of the mission, potentially as long as 20 years, and beyond. This report and the scientific discoveries that follow are extended thank-you notes to the 20,000 team members. The telescope is working perfectly, with much better image quality than expected. In this and accompanying papers, we give a brief history, describe the observatory, outline its objectives and current observing program, and discuss the inventions and people who made it possible. We cite detailed reports on the design and the measured performance on orbit.Comment: Accepted by PASP for the special issue on The James Webb Space Telescope Overview, 29 pages, 4 figure

Finishing the euchromatic sequence of the human genome

The sequence of the human genome encodes the genetic instructions for human physiology, as well as rich information about human evolution. In 2001, the International Human Genome Sequencing Consortium reported a draft sequence of the euchromatic portion of the human genome. Since then, the international collaboration has worked to convert this draft into a genome sequence with high accuracy and nearly complete coverage. Here, we report the result of this finishing process. The current genome sequence (Build 35) contains 2.85 billion nucleotides interrupted by only 341 gaps. It covers ∼99% of the euchromatic genome and is accurate to an error rate of ∼1 event per 100,000 bases. Many of the remaining euchromatic gaps are associated with segmental duplications and will require focused work with new methods. The near-complete sequence, the first for a vertebrate, greatly improves the precision of biological analyses of the human genome including studies of gene number, birth and death. Notably, the human enome seems to encode only 20,000-25,000 protein-coding genes. The genome sequence reported here should serve as a firm foundation for biomedical research in the decades ahead

Orbital based electronic structural signatures of the guanine keto G-7H/G-9H tautomer pair as studied using dual space analysis

Electronic structural signatures of the guanine-7H and guanine-9H tautomers have been investigated on an orbital by orbital basis using dual space analysis. A combination of density functional theory (B3LYP/TZVP), the statistical average of model orbital potentials (SAOP/TZ2P) method and outer valence Green's function theory (OVGF/TZVP) has been used to generate optimal tautomer geometries and accurate ionization energy spectra for the guanine tautomer pair. The present work found that the non-planar form for both of the guanine keto pair possesses lower energies than their corresponding planar counterparts, and that the canonical form of the guanine-7H tautomer has slightly lower total energy than guanine-9H. This latter result is in agreement with previous experimental and theoretical findings. In the planar guanine pair the geometric parameters and anisotropic molecular properties are compared, focusing on changes caused by the mobile proton transfer. It is demonstrated that the mobile proton only causes limited disturbance to isotropic properties, such as geometry and the energetics, of the guanine keto tautomer pair. The exception to this general statement is for related local changes such as the N(7)-C(8) and C(8)-N(9) bond length resonance between the single and double bonds, reflecting the nitrogen atom being bonded with the mobile proton in the tautomers. The mobile proton distorts the electron distribution of the tautomers, which leads to significant changes in the molecular anisotropic properties. The dipole moment of guanine-7H is altered by about a factor of three, from 2.23 to 7.05 D (guanine-9H), and the molecular electrostatic potentials also reflect significant electron charge distortion. The outer valence orbital momentum distributions, which were obtained using the plane wave impulse approximation (PWIA), have demonstrated quantitatively that the outer valence orbitals of the tautomer pair can be divided into three groups. That is orbitals 1a''-7a'' and 18a', which do not have visible alternations in the tautomeric process (which consist of either pi orbitals or are close to the inner valence shell); a second group comprising orbitals 19a'-22a', 25a', 26a', 28a', 29a' and 31a', which show small perturbations as a result of the mobile hydrogen locations; and group three, orbitals 23a', 24a', 27a', 30a' and 32a', which demonstrate significant changes due to the mobile proton transfer and are therefore considered as signature orbitals of the G-7H/G-9H keto tautomeric process

Understanding the Role of Electron-Driven Processes in Atmospheric Behaviour

MELVILLE, US