Theoretical designing of novel heterocyclic azo dyes for dye sensitized solar cells

Since, the organic dyes that harness sunlight are generally considered as the heart of the dye sensitized solar cells (DSSC), the present study was carried out with the aim to design heterocyclic azo dyes that can be potentially used in DSSC application. Hereby, the analysis based on density functional theory (DFT) and time-dependent DFT calculations of the geometries, electronic structures and absorption spectra of the dyes before and after binding to titanium oxide \((\hbox {TiO}_{2})\) were carried out and investigated in detail. The data obtained from these analyses were then used to determine the open-circuit photovoltage \((\hbox {V}_\mathrm{OC})\) , and to measure the important parameters such as the light harvesting efficiency (LHE) and the electron injection efficiency associated with the short-circuit photocurrent density \((\hbox {J}_\mathrm{SC})\) . Our investigation reveals that all dyes showed absorbance in the visible region (469–521 nm) with high oscillator strength \((f)\) (1.076–1.564) and LHE (0.9176–0.973). Moreover, we found that the dyes after binding to titanium oxide displayed slightly red-shifted absorption (475–527 nm) with improved oscillator strength \((f)\) (1.121–1.664) and LHE (0.921–0.979). In addition, all dyes showed high \(\hbox {V}_\mathrm{OC}\) (1.068–2.232 eV) and high driving force for the electron injection, thus leading to the larger \(\hbox {J}_\mathrm{SC}\) . Our findings indicate that the heterocyclic azo dyes investigated in the current study can display better light to power conversion efficiency if used in the DSSC system, where the origin or their better performance can be attributed to the high \(\hbox {J}_\mathrm{SC}\) and \(\hbox {V}_\mathrm{OC}\) values found for these potential dyes. Based on the detailed study and investigation, we believe that the theoretical criteria used in the present study can be employed as an initial screening tool not merely to assess the properties of other organic dyes, but also to potentially design the organic azo dyes for their potential application in the DSSC systems.     

Escherichia coli of poultry food origin as reservoir of sulphonamide resistance genes and integrons

The antimicrobial resistance phenotype and genotype, the flanking regions of sulphonamide resistance genes and the integrons were analyzed in 166 Escherichia coli isolates recovered from poultry meat in Tunisia. High percentages of resistance were detected to ampicillin, streptomycin, nalidixic acid, sulphonamide and tetracycline (66-95%), and lower percentages to gentamicin, amoxicillin-clavulanic acid and cefoxitin (1-4%). The bla_TEM, tet(A)/tet(B), aph(3′)-Ia, aac(6′)-Ib-cr, aac(3)-II and cmlA genes were identified in 92, 82, 29, 2, 2 and 7 isolates, respectively. Class 1 and/or class 2 integrons were detected in 52% of E. coli isolates and five different gene cassette arrangements were identified in the variable regions of class 1 integrons, which included antimicrobial resistance determinants. Sixty-eight isolates contained the sul1 gene and 37 of them presented this gene into a class 1 integron structure. The sul3 gene was detected associated with non-classic class 1 integrons in 4 out of 46 sul3-positive isolates. The sul2 gene was detected in 66 isolates, 51 of them were linked to strA/B genes in seven different genetic structures. Seventy-three-per-cent of integron-positive isolates presented resistance to at least five different antimicrobial families versus 38.7% of integron-negative isolates. Our study highlights the role of commensal E. coli isolates from poultry meat as an important reservoir for sulphonamide resistance genes and integrons carrying antimicrobial resistance genes.     

Caracterisation de l'evaporation profondeDeep evaporation characterizationCharakterisierung der verdampfung in der tiefe eines porösen körpersИ/sиapeниe взчne зaглyблeни

Water evaporation from an homogeneous porous media, which is submitted to radiative and convective fluxes on its interface with air, is analysed by the energy balance equations and the classical transfer equations. Two Ievels are considered: the surface of the body, or its interface with air, and the deep front of evaporation. In this first analysis, the part located between these two levels is considered only as the site of a heat conductive flux and a water vapour flux, all liquid water flux is supposed negligible compared with water vapour flux. Then, it is possible to express the density of latent heat flux and the equilibrium values which characterize the level of the evaporation front and the surface of the body, such as temperature and water vapour pressure. These expressions are functions of the characteristics of air flow, radiative balance and coefficients, mainly two unidimensional numbers one of which has been used in the study of heat-transfer phenomena by Luikov [1]; these coefficients are the Brun numbers referred to heat and mass transfer.     

Experimental study of combustion performances and emissions of a spark ignition cogeneration engine operating in lean conditions using different fuels

This work presents an experimental study describing a six-cylinder spark ignition engine running with a lean equivalence ratio, high compression ratio, ignition delay and used in a cogeneration system (heat and electricity production). Three types of fuels; natural gas, pure methane and methane/hydrogen blend (85% CH₄ and 15% H₂ by volume), were used for comparison purposes. Each fuel has been investigated at 1500 rpm and for various engine loads fixed by electrical power output conditions. CO, CO₂, HC, and NOx emissions values, and exhaust gas temperature were measured. The effect of fuel composition on engine characteristics has been studied. The results show, that the hydrogen addition increased HC emissions (around 18%), as well as performance, whilst it reduced NO_x (around 31%), exhaust gas temperature, CO and CO₂.     

The impact of cooling water types on the cement clinker properties

This paper studied the influence of the different water types on clinker properties. It concern with cement plants which are using the water for cooling the clinker (El-Minia white cement plant). The water types are Nile, ground and deionized water. The cooling was mad suddenly for clinker by three water types at the same time. The paper discusses the physical and chemical analysis and algal detection of all water types. It also discusses the chemical and physical analysis for kiln feed, clinker. The analysis of water showed that the concentration of dissolved salts in groundwater is higher than Nile water. The concentration of algae gave opposite direction; the algae concentration in Nile water is higher than groundwater. While the deionized is completely free from dissolved salts and algae. The cement tests for clinker which treated by the different water types showed that the cement strength was reducing when used the Nile water with high algae count. From another side, the high concentration of dissolved salts in groundwater does not affect on strength. The water contained the algae prevent the complete crystallization of calcium silicate for clinker. The results also showed that the best type of water, which improved cement compressive strength ranged according to algae count by the sequence deionized water > groundwater > Nile water.     

Reactions of 4-Benzylidene-3-methyl-5-oxopyrazoline,pyrazole blue,and rubazoic acid with GRIGNARD reagents

While 4-benzylidene-3-methyl-5-oxopyrazoline 1 and pyrazole blue 2 with GRIGNARD reagents gave 1,4-addition, rubazoic acid 3 gave 1, 2-addition on both sides with ethylmagnesium bromide.     

Analysis matching of 5 GHz operating planar antenna EM characteristics between rigorous raw model,simulation and measurements

Journal of Computational Electronics - One of the challenges in antenna analysis is achieving concordance between the results of a purely theoretical numerical method application and commercial...     

Hybrid spatial‐spectral MoM analysis of microstrip structures

In this paper, a new hybrid method formulation to resolve the mixed potential integral equation in an efficient and a fast approach, which is based on a simultaneous formulation in both spatial and spectral domains, is proposed. The entries of the method of moments matrix are then given by the sum of two integrals. The first one is expressed in the spatial domain. This part is analytically evaluated after a development in Taylor series of the exponential terms in the function to integrate. The integrals expressed in the spectral domain have a finite range, and they are calculated using numerical integration. Then the convergence problem is avoided in this approach. A good agreement between the simulated and measured results has been achieved. Copyright © 2015 John Wiley & Sons, Ltd.     

Structure-Activity Studies Reveal Scope for Optimisation of Ebselen-Type Inhibition of SARS-CoV-2 Main Protease

The reactive organoselenium compound ebselen is being investigated for treatment of coronavirus disease 2019 (COVID-19) and other diseases. We report structure-activity studies on sulfur analogues of ebselen with the Severe Acute Respiratory Syndrome coronavirus 2 (SARS-CoV-2) main protease (M^pro), employing turnover and protein-observed mass spectrometry-based assays. The results reveal scope for optimisation of ebselen/ebselen derivative- mediated inhibition of M^pro, particularly with respect to improved selectivity.