Aromaticity, antiaromaticity and chemical bonding in the ground (S0), first singlet excited (S1) and lowest triplet (T1) electronic states of disulfur dinitride, S2N2, were investigated by analysing the isotropic magnetic shielding, σiso(r), in the space surrounding the molecule for each electronic state. The σiso(r) values were calculated by state-optimized CASSCF/cc-pVTZ wave functions with 22 electrons in 16 orbitals constructed from gauge-including atomic orbitals (GIAOs). The S1 and T1 electronic states were confirmed as 11Au and 13B3u, respectively, through linear response CC3/aug-cc-pVTZ calculations of the vertical excitation energies for eight singlet (S1–S8) and eight triplet (T1–T8) electronic states. The aromaticities of S0, S1 and T1 were also assessed using additional magnetic criteria including nucleus-independent chemical shifts (NICS) and magnetic susceptibilities calculated at several levels of theory, the highest of which were CCSDT-GIAO/cc-pVTZ for S0 and CASSCF(22,16)-GIAO/aug-cc-pVQZ for S1 and T1. The results strongly suggest that: 1) the S0 electronic ground state of S2N2 is aromatic but less so than the electronic ground state of benzene; 2) S1 is profoundly antiaromatic, to an extent that removes any bonding interactions that would keep the atoms together; and 3) T1 is also antiaromatic, but its antiaromaticity is more moderate and similar to that observed in the electronic ground state of square cyclobutadiene. S2N2 is the first example of an inorganic ring for which theory predicts substantial changes in aromaticity upon vertical transition from the ground state to the first singlet excited or lowest triplet electronic states.
Recently, important efforts have been made in an attempt to search for the cheapest and ecofriendly alternatives adsorbents. In the present work, waste molasses from Iraqi date palm (Zahdi) had been used as a provenance to produce charcoal for the removal of methylene blue (MB) dye from water. The optimum prepared charcoal was obtained at 150 C, by increasing temperature to 175 C, the charcoal had almost converted to ash. The obtained charcoal have been inspected for properties using scanning electron microscope (SEM), atomic force microscope (AFM), porosity and surface area. Adsorption data were optimized to Langmuir and Freundlich and adsorption parameters have been evaluated. The thermodynamic parameters like a change
... Show MoreThe use of essential services in modern constructions, such pipes, and ducts, became important, placing these pipes and ducts underneath the soffit of the beam. They made a ceiling sandwich, and that causes to reduce the height of the floor, so the presence of the opening in the beam saves the height of the floor. In this paper, the investigation of the beam response of reinforced concrete simply supported rectangle beams with square web openings is presented, including a number of the web openings (two, four, and eight), in addition to its use in strengthening the member at the openings (when the beam is planned before casting, internal deformation steel bar is used, and in case of the opening is existing in the b
... Show MoreIn this article, performing and deriving te probability density function for Rayleigh distribution is done by using ordinary least squares estimator method and Rank set estimator method. Then creating interval for scale parameter of Rayleigh distribution. Anew method using is used for fuzzy scale parameter. After that creating the survival and hazard functions for two ranking functions are conducted to show which one is beast.
A cantilever beam is made from composite material which is consist of (matrix: polyester) and (particles: Silicon-Carbide) with different volume fraction of particles. A force is applied at the free end of beam with different values. The experimental maximum deflection of beam which occurs at the point of the applied load is recorded. The deflection and slope of beam are analyzed by using FEM modeling. MATLAB paltform is built to assemble the equations, vector and matrix of FEM and solving the unknown variables (deflection and slope) at each node. Also ANSYS platform is used to modeling beam in finite element and solve the problem. The numerical methods are used to compare the results with the theoretical and experimental data. A good ag
... Show MoreThe purpose of this preliminary study is to verify the possibility of using Iraqi Zahdi date palm biomass as a resource for biogas production, methane in particular using thermophilic anaerobic digestion with waste water treatment activated sludge. Moreover, is to investigate the influence of extra nutrients addition to the digestion mixture. Biogas was captured in sealed jars with remote sensing modules connected to computer with integrated program to record the gas pressure continuously. A total gas pressure with 67% Methane was produced from date pulp waste fermentation with a yield of 0.57 Lit for each gram volatile solid of substrate. Addition of 1% yeast extract solution as nutrient increased Methane yield in liters by 5.9%. This i
... Show MoreConstruction projects are complicated in nature and require many considerations in contractor selection. One of the complicated interactions is that between performance with the project size, and contractor financial status, and size of projects contracted. At the prequalification stage, the financial requirements restrict the contractors to meet minimum limits in financial criteria such as net worth, working capital and annual turnover, etc. In construction projects, however, there are cases when contractors meet these requirements but show low performance in practice. The model used in the study predicts the performance by training of a neural network. The data used in the study are 72 of the most recent roadw
... Show MorePermanent deformation (Rutting) of asphalt pavements which appears in many roads in Iraq, have caused a major impact on pavement performance by reducing the useful service life of pavement and creating services hazards for highway users. The main objective of this research is investigating the effect of some contributory factors related to permanent deformation of asphalt concrete mixture. To meet the objectives of this research, available local materials are used including asphalt binder, aggregates, mineral filler and modified asphalt binder. The Superpave mix design system was adopted with varying volumetric compositions. The Superpave Gyratory Compactor was used to compact 24 asphalt concrete cylindrical specimens. To collect t
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