Engineering Innovations Vol. 3

Abstract: In this paper, the axially-symmetric MHD (magnetohydrodynamic) slip fluid flow and heat transfer between a rotating disk and a stationary permeable disk has been examined. The physical system is comprised of a free-fluid region with an underlying fluid-saturated porous bed with a solid base. The fluid flow within the free-fluid region is modeled using the Navier-Stokes equation, whereas the flow within the porous bed is described using the Brinkman equation. The governing equations of fluid flow and heat transfer, along with the associated boundary conditions, are reduced to a system of ordinary differential equations using suitable similarity transformations. A series expansion technique is then employed in order to obtain analytical approximations for the velocity and temperature distributions. The results produced in this study are presented in graphical form. Unless otherwise stated, the following non-dimensional values are used for the numerical calculations: Hartmann number M=1, Reynolds number R=0.1, Darcy parameter beta=0.05, thermal conductivity ratio lambda=0.5, Eckert number Ec=10, slip parameter N^*=0.05, eta=1, and Prandtl numbers Pr_1=Pr_2=10. The influence of the Darcy parameter, Hartmann number and thermal conductivity ratio on the flow velocity and fluid temperature are investigated.

Abstract: Reverse Osmosis (RO) Brine is waste generated from the desalination process using the RO method. RO Brine is generally directly thrown back into the sea, even though it has the potential to be reprocessed because it still contains a variety of ions in it. The best method in RO Brine processing is Electrodialysis. But it has a problem of decreased membrane performance caused by the formation of fouling. The fouling problem can be overcome by doing a pretreatment process to eliminate impurities contained in RO Brine, one of which is Ca²⁺. The existence of Ca²⁺ can trigger the formation of CaSO₄ deposits. Therefore, it needs excess reagent Na2CO3 with a certain amount to eliminate the whole Ca²⁺. Currently, it isn’t yet known the best pretreatment conditions that can eliminate impurities ions and produce high concentrations of NaCl. Pretreatment trials are needed in various variations of reagents amount to reduce impurities. The purpose of this study is to find out the best RO Brine pretreatment process that will later be used for the electrodialysis process to produce high NaCl recovery. The best results were obtained in the pretreatment process with variations NaOH excesses by 15% and Na₂CO₃ by 30% from the ideal stoichiometry.

Abstract: This paper presents the results of research and test of the self-designed and manufactured rotary friction welding machine. Tensile test results show that the tensile strength of the material after welding is satisfactory according to the standards of the material; the elongation is within the elongation limit of the welding specimen; the yield limit is greater than the minimum yield limit of the material. The parameters of the welding equipment are guaranteed according to the design requirements.

Abstract: The use of viscoelastic sheets in the hull of vessels built from GFRP has been raised in previous works as an option to protect the vessel from the destructive damage of slamming. The present work proposes its use in boats previously built by adhering to the outside of the hulls of the ships. Its installation process is shown, and this new type of installation is compared. Through impact tests with GFRP panels, it is shown that the viscoelastic material maintains its property of absorbing slamming energy and protecting the interior of the laminate. Fatigue tests on the order of 5x10⁴ cycles are carried out to evaluate the impact force, the accelerations that deform the laminate and the virtual energy work imposed on the panel. This option shows that designers have a new option to protect the hull of already built boats.

Abstract: The performance of the SiO₂ MOSFET-based absorber as a solution to arching within transmission lines (used for RF signal transportation) has been realized and analyzed at 28 GHz using the reflected signal from the R_X branch of 5G massive MIMO base station. The reflected signal from the receiver (R_X) branch of base stations may lead to interference, thus creating a performance reducing condition (arching) within the transmission lines. For optimum performance in the 5G regime, the SiO₂ MOSFET has been used to solve the problem of arching within the transmission line under large field intensities of a standing wave resulting from the impedance. The SiO₂ MOSFET-based absorber has been observed for a reflectivity of -79.5 dB and a rectification efficiency greater than 17 %