Spectroscopic Electrochemical Properties and DFT Calculation of 1-Aryltriazenes

Electrochromic materials are of great interest for their potential in eyewear protection and data storage devices, as they change colors in response to electrochemical switching. While many of the systems currently used are based on inorganic materials, organic materials such as triazenes have emerged as viable alternatives due to their unique properties, including optical properties. Triazenes are a class of organic compounds with three consecutive nitrogen atoms in an acyclic arrangement, and they have been used for a variety of applications in medicinal and synthetic chemistry. However, the effects of solvents on the UV-visible absorption spectrum of triazenes have not been fully investigated. The neutral molecules of 3,3-diisopropyl-1-phenyltriazene and 1-(4-chlorophenyl)-3-cyclopentyltriazene in acetonitrile, the UV-visible spectra corresponded respectively to HOMO → LUMO transitions with a large maximum absorption at 299.74 nm (4.1364 eV) and 299.57 nm (4.1387 eV) and the most intense oscillator strength (f = 0.6988) and (f = 0.7372). These results suggest that the electronic transitions of the compounds are highly influenced by the nature of the substituents on the triazene unit, as well as the solvent used in the experiment. The redox couple 0.92 and -0.44 V/Ag/AgCl is attributed to the phenyl group. Compound III showed an oxidation and reduction peak respectively -0.27 and -0.8 V/Ag/AgCl attributed to the phenyl molecule. The study concluded that all three compounds were electroactive and exhibited reversible characteristics with oxidizing/reducing couples. This study aims to contribute to research on the optical properties of triazenes compounds and the application of quantum chemical calculation methods for understanding their molecular structures. By investigating the solute-solvent interactions occurring in the solvation shell of the solutes, we aim to gain insights into the effects of solvents on the UV-visible absorption spectrum of triazenes. Our findings may have implications for the development of functionalized triazenes as potential electrochromic materials.

Optimization PV/Batteries System: Application in Wouro Kessoum Village Ngaoundere Cameroon

This paper presents the optimization of the PV/battery system including extrapolation of the electrical demand. Matlab software was chosen to implement the algorithm. PVC, the number of PV modules and battery capacity increase with increasing electrical demand. This makes it possible to predict the device according to the electrical demand. Particle swarm optimization is used to minimize the total cost of the system over 20 years. The average cost of energy is $0.369/kWh.

Greenhouses Gases, Carbonyls, and Volatile Organic Compounds Surface Flux Emissions at Three Final Waste Disposal Sites Located in the Metropolitan Area of Costa Rica

The surface flux emissions for volatile organic compounds (VOC’s) (alcohols and aromatic species), priority carbonyls and greenhouse gases, were measured in three different final disposal sites for urban solid waste located in the metropolitan area of Costa Rica, between July and October 2014. The emissions fluxes were determined using the static sampling chamber technique coupled to two different adsorption tubes: active charcoal (Supelco, ORBO 32) to capture BTEX and alcohols;and 2,4-DNPH coated silica gel (SKC, 226-119) for carbonyls. As for the VOCs, the BTEX, Alcohols, and Carbonyls total fluxes were in the range of 3 to 258, 1 to 318 and 0.4 to 8.5 mg/(m2d&#237a), respectively. The magnitudes per site were in the following order La Carpio > El Huaso > Rio Azul. Ethanol and BTEX presented a high correlation in all the cases because possibly they are sharing the same sources or formation mechanisms. The emission fluxes spatial distributions among the sites were very variable and dependent on the location of the active cells and their age. Only La Carpio showed a more homogeneous distribution due to its middle age.

Use of Orbital Images and Interpolation Techniques: Climate Monitoring in Permanent Preservation Area (Humid Subtropical Climate)

The present work sought to demonstrate the importance using geoprocessing techniques and methodologies in the identification and analysis of the temporal and spatial distribution of air temperature. Therefore, an environment with difficulties for systematic monitoring of climatic elements was selected in the Serra da Esperançaárea, southern region of the State of Paraná. Two methodologies established in geoprocessing were used: the first deals with the interpretation of orbital images and the second makes reference to the interpolation of surface data. These methodologies, used in an integrated way, made it possible to know the relationship between the spatial and temporal distribution of air temperature with vegetation and the terrain altimetry. The air temperature data were monitored at 4 (four) points, following the contours of the federal highway that passes through the study area. Satellite images were obtained of July 26th, 2015 and January 18th, 2016, representing winter and summer southern conditions. The results indicated that this relationship exists and that in the absence of absolute data monitored at conventional collection points, geostatistics techniques allow good estimation. Moreover, this methodology can be used to control land use change in permanent preservation areas.

Multivariate Analyses of Potentially Toxic Elements along an Industrialized Urban River in Northern Taiwan

The Ker-Ya River flows through the high-tech industrial park and urban residential areas of Hsin-Chu in northern Taiwan. Major and trace element concentrations of waste effluents, river water, and sediment samples collected during 2017 along the Ker-Ya River were analyzed to elucidate the distribution pattern of potential pollutants. Principal component analyses were applied, and four major contaminant associations were recognized: 1) Ce, Co, Fe, La, V, and Cr;2) Cu and Ni associated with Hg, Ni, P, Ga, W, In, and Ti;3) B, Li, Ba, Ca, and Ag;and 4) Sn with Zn, In, and Cd. All associations are considered to be mainly anthropogenic. Although the element associations recognized from the water samples are not exactly the same as those from the sediment samples but nevertheless, they are similar, suggesting that the short-term and long-term distribution patterns are consistent. The A association accounts for the most variance in the data and exhibits the widest distribution, suggesting the existence of contaminant sources in the upper and lower reaches, respectively. The sediments near the outlet of the city sewage plant also contain association A elements, signaling incomplete processing of the diverged waters sent to the plant at the river mouth. The B association (mainly Cu and Ni) appeared mainly in the upper and middle reaches, indicative of sources from industries in the upper reaches and the tributary Nan-Men Creek. The C association (B, Ba, Ca, and Li) was limited to the center part of the river, probably attributable to a nearby paper mill. The D association (primarily Sn, In, and Zn) was present in the top point of the middle reaches, suggesting the presence of other contaminant sources in the upper reaches. Although a total of four concomitant associations were recognized, none of the elements exceeded the drinking water standard, suggesting that there was no severe pollution present.

Study of Attapulgite as an Additive in Reinforced Concrete by Substitution of Cement and Its Effects on the Durability Properties of Hardened Concrete

The valorization of Senegalese attapulgite clay in concrete, as a solution against the exhaustion of the cement deposits was studied. In that purpose, attapulgite was first calcined at 800°C to make it reactive and added in concrete by substitution of Portland cement (CEM I 52.5N) at contents of 0, 5 and 10% by conserving a constant water/cement ratio value of 0.65. The effects of the partial replacement of cement by attapulgite on the physicochemical and mechanical properties of the concrete as well as on the steel-concrete bond were examined. For this purpose, the water porosity, the intrinsic permeability and the density of the clay-based concrete were evaluated. Compression, tensile and pull-out tests were carried out to determine the impact of clay on the Young modulus, the compressive and tensile strengths and the steel-concrete bond. This study was completed by a characterization of the pozzolanic reactivity of calcined attapulgite. All the results of these studies were compared with those of Portland cement as a reference. The substitution of cement by attapulgite up to 10% in concrete has only a small influence on its porosity and permeability and confers to the concrete gain in compressive strength of 11%. However, it caused a loss of steel-concrete bond of 10%.