Special Issue Nanofiltration Membranes
Nanofiltration (NF) is a de novo class of membrane filtrations with unique properties ranging from ultrafiltration to reverse osmosis. Thanks to their high removal performance, NF membranes have gained increasing attention from both academia and industry for various applications, especially in water and wastewater treatment and desalination. However, the NF process still requires further improvement in terms of selectivity, separation efficiency, membrane fabrication, operation requirements, and sustainability.
This Special Issue on “Nanofiltration Membranes: Recent Advances and Environmental Applications” of the Membranes seeks to include but is not limited to recent progress in emerging NF membranes fabrication and modification, polymeric and ceramic NF membrane, hybrid and composite NF membranes, organic solvent NF, positively charged NF membranes, NF module and process design, NF removal mechanisms, fouling mitigation strategies, new environmental applications of NF, and predictive modelling of NF membrane processes. Authors are invited to submit their latest original results as full papers or short communications. Furthermore, state-of-the-art and critical reviews and analysis papers are welcome.
Advantages of GRE pipes
Glass Reinforced Epoxy or GRE pipes are a valid alternative to carbon steel pipes especially for corrosive, aggressive and normal environments.
GRE pipe technology is based on the Discontinuous Filament Winding process using high strength fiberglass (E-glass) and amine cured epoxy resin as basic material. Numerically controlled machines manufacture the product on a mandrel according to the cross section filament winding process. The continuous glass fibers are helically wound at predetermined angles and bonded with the epoxy resin.
Lightweight and easy to handle and install GRE pipes have a smooth internal surface that reduces friction and enables a high pipe flow capacity. Low thermal conductivity of GRE pipes in comparison to steel (only 1% of steel values), minimizes the cost of insulation and the heat loss. Another major benefit of GRE pipes is that once installed they are virtually maintenance-free.
GRE pipe is well suited for environments where the corrosion resistance at competitive prices is required.
GRE pipes offer a unique combination of high mechanical, thermal and chemical resistance which is obtained by the selection of high performance components and a proper design of the structure. The inner liner, which is made by a resin rich layer reinforced with C-glass or synthetic veil, guarantees the pipe water tightness, its chemical and temperature resistance. The mechanical resistant layer is composed of successive layers of pre-stressed glass roving impregnated with epoxy resin and orientated with a precise, predetermined angle selected in order to achieve the properties required. The resin and the hardener system are selected with the consideration of the combination of properties required from the finished product. The glass reinforcement in the form of continuous roving is chosen base on its compatibility with epoxy resin. It is applied on the rotating mandrel following the hoop (radial) winding pattern combined with a helical winding pattern at an angle ranging from 45?° to 90?°.
Glass tape or unidirectional reinforcements can be used to obtain local reinforcement. An external resin coating reinforced with a synthetic veil adds a finish to the pipe. Should weathering be a problem a UV inhibitor will be added to the coating.
The Early Rotor Blades
Early helicopters like the famous Bell 47 came with main rotor blades made of wood. The inherent characteristic of wood being strong and flexible provided the perfect material for early rotor blade designs.
There were problems however as wood can easily be damaged by woodpeckers, dust and stones, and even rain causing the blade to swell leading to severe vibrations from an out of balance rotor system.
1. When the RO system is working or there is pressure in the frp membrane housing, it is strictly prohibited to knock, disassemble or move the membrane housings. The surrounding vibration source environment must be strictly controlled.
2. In order to ensure the inner surface of the fiberglass membrane housing clean, manufacturer use a neutral cleaning solution to clean. It is strictly forbidden to use concentrated hydrochloric acid, concentrated sulfuric acid, etc. as cleaning fluid.