Benchmarking Multiconfiguration Dirac–Hartree–Fock Calculations for Astrophysics: Si-like Ions from Cr xi to Zn xvii

The multiconfiguration Dirac–Hartree–Fock (MCDHF) and relativistic configuration interaction methods are used to provide excitation energies, lifetimes, and radiative transition data for the 604 (699, 702, 704, 704, 704, and 699) lowest levels of the 3s 23p 2, 3s3p 3, 3s 23p3d, 3p 4, 3s3p 23d, 3s 23d 2, 3p 33d, 3s3p3d 2, 3s3d 3, 3p3d 3, 3p 23d 2, 3s 23p4s, 3s 23p4p, 3s 23p4d, 3s 23p4f, 3s3p 24s, 3s3p 24p, 3s3p 24d, 3s3p 24f, 3s 23d4s, 3s 23d4p, 3p 34s, 3p 34p, 3s3p3d4s, 3s 23p5s, and 3s 23p5p configurations in Cr xi, (Mn xii, Fe xiii, Co xiv, Ni xv, Cu xvi, and Zn xvii). Previous line identifications of Fe xiii and Ni xv in the EUV and X-ray wavelength ranges are reviewed by comprehensively comparing the MCDHF theoretical results with available experimental data. Many recent identifications of Fe xiii and Ni xv lines are confirmed, and several new identifications for these two ions are proposed. A consistent atomic data set with spectroscopic accuracy is provided for the lowest hundreds of levels for Si-like ions of iron-group elements of astrophysical interest, for which experimental values are scarce. The uncertainty estimation method suggested by Kramida, applied to the comparison of the length and velocity line strength values, is used for ranking the transition data. The correlation of the latter with the gauge dependency patterns of the line strengths is investigated.

Application of Myrcia splendens tannins in the composition of urea-formaldehyde adhesive for sustainable wood bonding

Tannins from Myrcia splendens from the Amazon rainforest were used for the first time in the formulation of a urea-tannin-formaldehyde (UTF) resin. The objective was to evaluate the effect of different tannin proportions on the glue line performance in Pinus sp. woods, glued with UTF adhesive. The tannins were extracted in a water bath, using 1500 mL of water and 100g of dry bark (liquor/bark 15:1), with addition of 3% Na2SO3, at a temperature of 70 °C for three hours. The adhesives formulations were based on the gradual replacement of mass of the urea-formaldehyde (UF) adhesive by tannin powder, totalizing four compositions and one control treatment. UTF adhesives were evaluated for their physicochemical properties, shear bond strength (wet and dry) and wood failure. The addition of M. splendens tannins to the urea formaldehyde adhesive promoted an increase in glue line strength. The proportion of 5.0% of tannins proved to be ideal in the formulation of the UTF adhesive, considering all the parameters evaluated. Thus, this study proves the potential use of Amazonian tannins from Myrcia splendens in the partial composition of more sustainable UTF adhesives.

Towards an Optical Gas Standard for Traceable Calibration-Free and Direct NO2 Concentration Measurements

We report a direct tunable diode laser absorption spectroscopy (dTDLAS) instrument developed for NO2 concentration measurements without chemical pre-conversion, operated as an Optical Gas Standard (OGS). An OGS is a dTDLAS instrument that can deliver gas species amount fractions (concentrations), without any previous or routine calibration, which are directly traceable to the international system of units (SI). Here, we report NO2 amount fraction quantification in the range of 100–1000 µmol/mol to demonstrate the current capability of the instrument as an OGS for car exhaust gas application. Nitrogen dioxide amount fraction results delivered by the instrument are in good agreement with certified values of reference gas mixtures, validating the capability of the dTDLAS-OGS for calibration-free NO2 measurements. As opposed to the standard reference method (SRM) based on chemiluminescence detection (CLD) where NO2 is indirectly measured after conversion to NO, titration with O3 and the detection of the resulting fluorescence, a dTDLAS-OGS instrument has the benefit of directly measuring NO2 without distorting or delaying conversion processes. Therefore, it complements the SRM and can perform fast and traceable measurements, and side-by-side calibrations of other NO2 gas analyzers operating in the field. The relative standard uncertainty of the NO2 results reported in this paper is 5.1% (k = 1, which is dominated (98%) by the NO2 line strength), the repeatability of the results at 982.6 µmol/mol is 0.1%, the response time of the instrument is 0.5 s, and the detection limit is 825 nmol/mol at a time resolution of 86 s.

COMPARISON STUDY BETWEEN SPECTROSCOPIC ANALYSIS FOR (ZN,SN) PLASMA BY LIBS

this article a spectroscopic research on laser-produced Tin and Zinc plasmas using the optical emission spectroscopy (OES) technique. Plasmas can be produced from a solid tin and zinc targets irradiated with a pulsed laser in room environments. The spectrum is recorded for the Sn, Zn laser plasma Nd: YAG with a wavelength of (1064) nm, a duration of (9) ns, and a frequency of (6) Hz and a focal length of (10) cm within the energy range (300-800)mj. By using the ratio line strength formula, the electron temperature (Te) can be calculated and the result is for Zinc (Zn) plasma (2.11 ev) and tin (Sn) plasma (1,227 ev). The Saha-Boltzmann equation will be used to calculate electron density (ne) in this method and the values for zinc (Zn) (3.3 cm-3)and tin (Sn) (2.1 cm-3). The plasma parameters, such as plasma (fp), Debye duration (λD), and Debye number (ND), were calculated in the proposed document.

Gender Faultline Strength on Boards of Directors and Strategic Change: The Role of Environmental Conditions

Drawing on the notion of “fault lines” and the upper echelons perspective, we argue that the gender fault line strength of a board of directors is negatively related to strategic change. More interestingly, while gender fault line strength negatively relates to strategic change under low levels of environmental complexity, environmental dynamism, and environmental munificence, it is positively related to strategic change when environmental complexity, environmental dynamism, and environmental munificence are at high levels. The analyses of panel data of 5781 firm-year observations of 1171 Chinese firms provide support for the hypotheses.