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Bearing plates made from plastic composites can be used as an alternative to their steel counterparts in rock bolt or soil nail applications. To achieve this goal, an existing recycled high-density polyethylene bearing plate was investigated and later modified to improve its engineering properties. Laboratory studies were conducted to determine the failure load of the existing and modified plates, and a numerical model was developed for complementary analysis. The results of both efforts clearly showed that the existing bearing plate was not adequate in terms of strength and creep properties, as it quickly yielded with large displacements at relatively low loads. In order to enhance the strength of the plate, both geometric and material modifications are made by our research group to obtain a more efficient plate. Numerical models were used to determine the frame layout, and a series of analyses were performed to evaluate the effects of frame thickness, number and arrangement. Once the design was optimized and finalized, a mold was created to match the new geometry for manufacturing new plates through injection molding. A test setup was also established in the laboratory and numerous compression tests were performed on the manufactured new plates. The measured load-displacement behavior of plates made of polyethylene and polyamide with a variety of additives were discussed separately. It was determined that the new plastic plates reinforced with polyamide through various additives have the potential to reach a strength up to 200–240 kN, which is at least two times higher than the existing one, with distinct economic advantages.

The purpose of this research is to establish a processing method for a wide-area nanometer scale periodic structure on the surface of a plastic plate in order to improve its hydrophobicity. We also evaluated the effect of a nanoperiodic structure applied in the uniaxial direction. Plastic plates of acrylonitrile–ethylene–styrene with dimensions of 100 × 100 mm2with a nanoperiodic structure on their surfaces were fabricated using a femtosecond laser and an injection molding technique. In the injection molding, the maximum transfer ratio for the depth reached as high as 0.79. When the nanoperiodic structure was applied in the uniaxial direction, the apparent contact angles did not decrease with respect to the direction of the ridges. As a result, the apparent contact angle increased by 20.4°, from 77.2° to 97.6° which is equivalent to 26%. In the six-month duration test, the sliding angle was initially decreased by applying the nanoperiodic structure. Additionally, the sliding angle was maintained between 20° and 38.3° during the duration test, which was lower than the angle for the flat plate at 42.7°. It can be considered that the depth was sufficient to maintain the sliding angle. In this condition, the contact angle hysteresis did not differ with or without the nanoperiodic structure on the surfaces, an effect that could be caused by surface dirt. In summary, the plastic plate was well drained and the characteristics were maintained for several months by forming the nanoperiodic structure on the surface. [ABSTRACT FROM AUTHOR]

A true-time-delay system for wideband continuous phased array beamforming employing a novel multiwavelength tunable fiber laser source with equally increased or decreased wavelength spacing is proposed. The wavelength tuning is realized by stretching or compressing the fiber Bragg gratings cascaded in the laser cavity. To ensure a wavelength tuning with equally increased or decreased wavelength spacing, the gratings are mounted onto a plastic plate with angles between adjacent gratings selected such that the forces applied to the gratings has an equal force increment. Time delays with equally increased or decreased time delay difference for the equally spaced wavelengths are obtained when the modulated lightwaves are reflected at different locations of a linearly chirped grating. A four-channel chirped grating based true-time-delay system using the proposed light source has been constructed and experimented. Equally increased or decreased time delays are obtained when the wavelengths are tuned [ABSTRACT FROM PUBLISHER]