The Third Conference for Engineering Sciences and Technology
http://dspace.elmergib.edu.ly/xmlui/handle/123456789/189
CEST 20202024-03-28T14:13:16ZCyclic Voltammetry Studies of PEO Processes in Alkaline and Silicate/Phosphate Electrolytes and Resulting Coatings
http://dspace.elmergib.edu.ly/xmlui/handle/123456789/241
Cyclic Voltammetry Studies of PEO Processes in Alkaline and Silicate/Phosphate Electrolytes and Resulting Coatings
Meshreghi, Husein; Gorbatkov, M.; Yerokhin, A.; Matthews, A.
A cyclic voltammetry (CV) method was employed to clarify the electrochemical behaviour of Al in alkaline silicate/phosphate electrolytes over a voltage range of 0 to 550V and study the growth process of plasma electrolytic oxidation (PEO) coatings on rectangular shape Al foil samples. The non-linear behaviour of the current – voltage curve reflects a combination of three processes, including dissolution, passivation and formation of PEO coating under discharge conditions. Different thickness distributions of oxide layer and residual aluminium along the sample length were observed. Similarly, the total Al consumed for the coating process at the edge of sample was more than in the middle. Silicate addition obstruct anodic dissolution of Al, which enhanced the oxide growth. While phosphate, in addition of promoting alpha phase formation it is also enhancing strong metal passivation and allow the breakdown voltage to be easily obtained. Breakdown voltage depends on the concentration and electrolyte composition. Under the studied conditions, we can also conclude that the sparking voltage decreases when electrolyte resistivity decrease which is consistent with Ikonopisov equation. However, which’s more surprising and unexpected in K electrolyte, is the earlier emission starting prior to the current starts increasing. There are a number of considerations used to determine the breakdown voltage such as reaching of maximum voltage, rapid voltage fluctuation. However, the appearance of visible sparking is not a criteria for detecting the dielectric breakdown as concluded in our study although many literatures considered this as criteria.
2020-12-03T00:00:00ZLammps as Nano-scale Lab to Estimate Fluid Thermal Properties from Molecular Dynamics
http://dspace.elmergib.edu.ly/xmlui/handle/123456789/238
Lammps as Nano-scale Lab to Estimate Fluid Thermal Properties from Molecular Dynamics
Alkhwaji, Abdusalam; Elbahloul, Salem; Farhat, Mohamed S.
On the one hand the complexity of nano-scale thermofluid system considered as an expensive to investigate experimentally, on the other there are available discrete models such as Molecular Dynamics model offers an affordable and accurate choice for researchers to perform nano-scale investigation to look at different fluid aspects. In this paper we demonstrate how engineers can benefit from the Molecular Dynamics simulation to estimate water thermal properties. Lammps software was used in this study to calculate water thermal properties. The atomistic model type of water which has been used is the four-site transferable intermolecular potential water molecules (TIP4PEW). The thermal properties of water to be estimated are thermal conductivity, viscosity, density, specific isochoric and isobaric heat capacities, Prandtl Number, and Volumetric thermal expansion coefficient. Results compared to experimental data, and showed very good agreement. That prove the usefulness of molecular dynamics simulation as an engineering research tools to investigate thermal properties of any fluid. This study suggests Lammps as an excellent simulation tools to perform computational studies of Thermofluid properties and consider Lammps as a cost affordable nanoscale lab, since it is an opensource software. The accuracy of Lammps depends on the quality of the force field. The results of these study were compared to experimental published water properties at temperatures of 288, 300, 312 and 324 K and pressure 1 atm.
2020-12-03T00:00:00ZSimulation of Butanol Production through Hydrogenation of Butanal: Effects of Different Reactor Schemes and Operating Conditions
http://dspace.elmergib.edu.ly/xmlui/handle/123456789/237
Simulation of Butanol Production through Hydrogenation of Butanal: Effects of Different Reactor Schemes and Operating Conditions
Saeid, Mohammed Faraj; Chin, Sim Yee
The simulation was performed to evaluate the impact of by-passing the second liquid phase reactor in the series due to the catalyst blockage problem leading to the shutdown in a butanol production plant. Butanal hydrogenation for the production of butanol was simulated using the Aspen Plus software package. The process thermodynamics was described by NRTL property model while the kinetic of the main and side reactions was represented by Pseudo-homogeneous model. The attested packed bed reactor model was subsequently used to simulate butanal hydrogenation at different reactor configuration, reactor operating conditions and reactor size. The targeted final total conversion was 99.5% of butanal. The butanal conversion increased with the increase of reaction temperature and residence time. On the other hand, the reactor pressure only affected the performance of the vapour phase reactor but not the liquid phase reactor. Conclusively, the idea of bypassing liquid phase reactor for hydrogenation of butanal in the series could be adopted to achieve the total targeted conversion, provided the plant is allowed to operate at a more severe operating condition. In the modified configuration I, the last reactor should operate at 166.5℃ and 16 bar whereas, in the modified configuration II, the reactor should operate at 285℃ and 30 bar, considering the safety factor.
2020-12-03T00:00:00ZSCARA Robot Links Length Optimization by Using MATLAB and Verification with SimMechanics and Solidworks
http://dspace.elmergib.edu.ly/xmlui/handle/123456789/236
SCARA Robot Links Length Optimization by Using MATLAB and Verification with SimMechanics and Solidworks
Mashali, Mustafa; Addeif, Miftah; Embarak, Mohamed
This paper aims for optimizing links length that consumed the minimum energy, for a customized SCARA robot. Nine link length combinations are tested and simulated. This research is a part of a project of designing a robotic arm for a packing task. Kinematic and dynamic studies are performed for a 2R robotic arm. The results of kinematic study which are angular displacement, angular velocity and angular acceleration for each joint are determined and exported to the dynamic study to obtain the torque and power consumed. The dynamic study is performed with the aid of MATLAB code, MATLAB/SimMechanics and Solidworks are used to simulate and analyze the dynamic of the robotic arm. The energy consumed for each link length combination using the three methods is calculated.
2020-12-03T00:00:00Z