Open Access Original Research Article

Density Functional Theory Investigation of the Doping Effects of Bromine and Fluorine on the Electronic and Optical Properties of Neutral and Ionic Perylene

Auwal A. Abubakar, A. B. Suleiman, A. S. Gidado

Physical Science International Journal, Page 1-13
DOI: 10.9734/psij/2021/v25i830273

Perylene and its derivatives are some of the promising organic semiconductors. They have found vast applications in many areas such as photovoltaic systems, organic light-emitting diodes, and so on. The instability of organic molecules under ambient conditions is one factor deterring the commercialization of organic semiconductor devices. Currently, most of the investigation of Perylene and its derivatives concentrated on its diimide and bisimide derivatives. In this work, an investigation of the effects of doping Bromine and Fluorine on the electronic and non-linear optical properties was carried out based on Density Functional Theory (DFT) as implemented in the Gaussian 09 software package. We computed the Molecular geometries of the molecules, HOMO-LUMO energy gap, global chemical indices and non-linear optical properties using the same method. The bond lengths and angles of the mono-halogenated molecules at different charge states were found to be less than that of the isolated Perylene. 1-fluoroperylene was found to be the most stable amongst the studied molecule for having the least bond angles and bond lengths. In the calculation of the energy bandgap neutral 1-fluoroperylene was observed to have the highest energy gap 3.0414 eV and 3.0507 eV for 6-31++G(d,p) and 6-311++G(d,p) basis sets respectively. These results were found to agree with the existing literature. This reconfirmed 1-fluoroperylene as the most stable molecule. The computations of the ionic molecules reported small values of the energy gap. The molecule with the most chemical hardness was obtained to be the neutral 1-fluoroperylene with a chemical hardness of 1.5253eV. All the ionic molecules results were found to be more reactive than their neutral form for having lower values of chemical hardness. For NLO calculations, the results showed an increment in their values with the ionic hybrid molecules having the largest values.  In the case of first-order hyper-polarizability, 1-bromoperylene (neutral), 1-fluoroperylene (neutral), 1-bromoperylene (anionic), 1-fluoroperylene (anionic), 1-bromoperylene (cationic) and 1-fluoroperylene (cationic) were found to be 73.93%, 1.71%, 83.9%, 39.2%,38.7% and 41.7% larger than that of Urea respectively. These calculated results make these hybrid molecules suitable for a wide range of optoelectronic applications.

Open Access Original Research Article

Two-Dimensional Modeling of Heat Transfers in a Ventilated Test Cell Built with Various Local Materials

Arouna Kaboré, Zoma Vincent, Palm Kalifa, Bathiebo Dieudonné Joseph

Physical Science International Journal, Page 14-31
DOI: 10.9734/psij/2021/v25i830275

The main objective of this work is to find a material that attenuates heat transfer and provides an acceptable indoor environment in the habitat of countries with a hot and dry climate like Burkina Faso. The absence of thermal regulations in Burkina Faso leads to the development of buildings constructed with materials that do not provide thermal comfort. This study therefore aims to compare the thermal performance of local materials such as BLT, BTC, concrete block and adobe in order to propose a material adapted to the hot climate. In this work, a modelling and simulation is conducted with the COMSOL software. The modelling is done on a building of dimensions 4m×3m×3m, built successively with cut laterite block (BLT), compressed earth block (BTC), hollow concrete block, and adobe. As for the simulation, it concerns the evolution of the internal and external temperature of the building. The heat flows on the Northern and Southern sides are neglected due to the overhang of the roof. The results obtained show that the cell built with BTC allows a 4°C reduction, the one built with BLT a 2°C reduction and the one built with adobe a 1.5°C gain compared to the one built with concrete block. Thus, the material that best meets the criteria is BTC.

Open Access Original Research Article

Study and Design of a Mobile Hydraulic Lift Table with Single Scissors

Guy Clarence Semassou, Roger Ahouansou, Edmond Claude Vodounnou, Guidi Tognon Clotilde

Physical Science International Journal, Page 32-43
DOI: 10.9734/psij/2021/v25i830276

The “BENIN TERMINAL” machines are maintained by company technicians who encounter difficulties in the operations carried out on these machines. In fact, it is about improving the procedure for installing and removing engines and gearboxes for BENIN TERMINAL mobile vehicles through the study and design of a single scissor lift table. It has a lifting capacity of 2 tons, a width of 900 mm, a total length of 1900 mm and a maximum height of 2000 mm using a hydraulic system. It works with 12 V batteries, simple and height-adjustable workspace. The lifting table also allows certain operations requiring an average height to be carried out.This device was developed for the BENIN TERMINAL garage in order to reduce the efforts and risks encountered by technicians when installing or removing engines and gearboxes on certain machines, in particular heavy machines such as Reach Stackers and 16ton forklifts.