A polymer waveguide with 4-channel graded-index circular cores is fabricated by the preform method. Very low loss (0.028 dB/cm at a wavelength of 850 nm) and high bandwidth (83 Gbps for 1 m, estimated) properties are experimentally demonstrated by the new waveguide for the first time. By densely aligning the cores during the preform fabrication, a waveguide with a pitch size of 56 mum and a cor...

The investigation of occupational Noise in a Petrochemical industry has been carried out. The noise levels were measured following standard procedure using calibrated sound pressure level meter Smart Sensor (Model AR854), Noise levels were measured at Gas plant, Olefin plant area, and Preform machine area of a petrochemical industry then questionnaires were designed to determine the health impa...

Calcium hexaluminate (CA6) was incorporated into the matrix of magnesio aluminate spinel-alumina (MA-A) via infiltration of a porous preform fabricated from α-Al2O3 and MgO powders with a saturated calcium acetate solution and subsequent firing, forming CA6/(MA-A) functionally composites with graded fracture toughness. Actually, the porous preform was partially and perpendicularly immersed (1/4...

3D weaving is a manufacturing technique for producing near net shape fiber preforms. These preforms can be processed into composite components using liquid molding techniques such as resin transfer molding (RTM) or the vacuum assisted process (VAP). One of the main advantages of 3D woven preforms is that the touch labor required to assemble them is minimal, leading to rapid and highly automated...

Composites consisting of Mg and MgB2 phases were fabricated by liquid-metal infiltration following two routes. First, a preform of MgB2 powders was pressure infiltrated at 800 °C with liquid Mg, which was subsequently solidified. Second, a preform of B powders was pressure infiltrated with liquid Mg at 700 °C, resulting in partial, in situ formation of the MgB2 phase. Subsequent annealing at 95...

The paper addresses the experimental investigation of the unit cell architecture in a structurally stitched multilayer carbon-fibre preform. Each layer is a multiaxial multiply non-crimp fabric (NCF) knit with a non-structural stitching. The term “structural” presumes here that the stitching yarn does not only consolidate the plies (as the non-structural one does) but also forms a 3D reinforcem...

Resin Transfer Molding (RTM) is widely used to manufacture polymer composite materials. In this process, the fiber preform is placed in a closed mold and thermoset resin is injected to saturate the preform. After the resin cures the mold is opened and the net shape composite part is obtained. With RTM, one is capable of making complex and high quality composite parts with short cycle times. How...