Preparation of bi-polar membranes and their application to hypochlorite production

Abstract

Flutter is a dangerous phenomenon encountered in flexible structures subjected to aerodynamic forces. This includes aircraft, helicopter blades, engine rotors, buildings and bridges. Flutter occurs as a result of interactions between aerodynamic, stiffness and inertia forces on a structure. The conventional method for designing a rotor blade to be free from flutter instability throughout the helicopter's flight regime is to design the blade so that the aerodynamic center (AC), elastic axis (EA) and center of gravity (CG) are coincident and located at the quarterchord. While this assures freedom from flutter, it adds constraints on rotor blade design which are not usually followed in fixed wing design. Periodic Structures have been in the focus of research for their useful characteristics and ability to attenuate vibration in frequency bands called "stop-bands". A periodic structure consists of cells which differ in material or geometry. As vibration waves travel along the structure and face the cell boundaries, some waves pass and some are reflected back, which may cause destructive interference with the succeeding waves. In this work, we analyze the flutter characteristics of a helicopter blades with a periodic change in their sandwich material using a finite element structural model. Results shows great improvements in the flutter forward speed of the rotating blade obtained by using periodic design and increasing the number of periodic cells.

Study on Acid/Base Formation by Using Sulfonated Polyether Ether Ketone/Aminated Polysulfone Bipolar Membranes in Water Splitting Electrodialysis

“…To characterize the electric and physical properties of the synthesized SPEEK and APSf, the swelling degree, ion-exchange capacity, and ion conductivity were measured. Measurement procedures followed previously adopted standards. , …”

Studies on Composite PVA-CA-NH4CF3SO3-Al2O3 Polymer Electrolyte for Electrochemical Devices

“…This confirms the complexation between the -OH groups of PVA-CA blend spectrum. The broad peak in this region indicates the significant number of -OH groups due to the unreacted -OH groups of PVA [11].…”

“…The transport of H + ions by Grottus mechanism through the coordinating sites of polymer matrix is the main reason for selecting this salt as a dopant in our system. From the earlier works reported by many researchers [9][10][11], the incorporation of inorganic fillers over the organic fillers reduces the cost of polymer electrolyte and thus the nano alumina was chosen to be a filler material. It helps to enhance H + transport through the expected interaction between the surface group of fillers and the migrating ions.…”