The production methods and materials ratio effect on the mechanical and physical properties of bamboo-plastic waste composites use for infrastructure development

Abstract: Plastic waste management has become a major concern environmentally across the globe, especially in developing countries. Plastic waste is synthetic and non-degradable material. However, it has great economic importance when recycle and used with other environmentallyfriendly materials to produce composites for structural engineering works. The production and application of this product will minimise the environmental problems of plastic waste. The usage of this composite material globally, will help reduce the high dependency on the limited forest timbers of soft and hardwoods. Bamboo fibre and plastic waste can be used to produce this composite which will be used for all load carrying elements. Bamboo fibre as reinforcement in polymers is on the increase because is biodegradable and environmentally friendly. This study looks at the effects of the production methods and the materials ratio effect on the mechanical and the physical properties of bamboo fibre and plastic waste composites boards. The fibres were extracted by mechanical method, whilst the wastes plastics are clean, dried and shredded before melting to mix with the fibres. The molten plastics wastes were poured into moulds mixed with fibres and then allowed to cool completely, after removed from the case of open casting. In compression moulding, the mould charge was pressed using the mould cover. Water absorption, bending strength, impact strength and thickness swelling were carried according to standard measures. The fibre content and production method influenced the mechanical and physical properties of the composites. Higher fibre content in the composite resulted in higher water absorption and thickness swelling. It was observed that water absorption was significantly influenced by the fibre content at α = 0.05. The hydrophilic nature of the fibres has increased water absorption and thickness swelling significantly leading to dimensional instability of the composites. Moulded composites showed better physical properties than open casting method, possibly due to reduced void space during polymerization. These tests suggested that reducing void space and incorporating fibres into the plastic improves the end use properties. These findings could be used to develop alternative materials for construction and manufacturing industries where load bearing is required

Left main bronchus compression due to main pulmonary artery dilatation in pulmonary hypertension: two case reports

Abstract. Pulmonary arterial dilatation associated with pulmonary hypertension may result in significant compression of local structures. Left main coronary artery and left recurrent laryngeal nerve compression have been described. Tracheobronchial compression from pulmonary arterial dilatation is rare in adults, and there are no reports in the literature of its occurrence in idiopathic pulmonary arterial hypertension. Compression in infants with congenital heart disease has been well described. We report 2 cases of tracheobronchial compression: first, an adult patient with idiopathic pulmonary arterial hypertension who presents with symptomatic left main bronchus compression, and second, an adult patient with Eisenmenger ventricular septal defect and right-sided aortic arch, with progressive intermedius and right middle lobe bronchi compression in association with enlarged pulmonary arteries

Lossless Astronomical Image Compression and the Effects of Noise

We compare a variety of lossless image compression methods on a large sample of astronomical images and show how the compression ratios and speeds of the algorithms are affected by the amount of noise in the images. In the ideal case where the image pixel values have a random Gaussian distribution, the equivalent number of uncompressible noise bits per pixel is given by Nbits =log2(sigma * sqrt(12)) and the lossless compression ratio is given by R = BITPIX / Nbits + K where BITPIX is the bit length of the pixel values and K is a measure of the efficiency of the compression algorithm. We perform image compression tests on a large sample of integer astronomical CCD images using the GZIP compression program and using a newer FITS tiled-image compression method that currently supports 4 compression algorithms: Rice, Hcompress, PLIO, and GZIP. Overall, the Rice compression algorithm strikes the best balance of compression and computational efficiency; it is 2--3 times faster and produces about 1.4 times greater compression than GZIP. The Rice algorithm produces 75%--90% (depending on the amount of noise in the image) as much compression as an ideal algorithm with K = 0. The image compression and uncompression utility programs used in this study (called fpack and funpack) are publicly available from the HEASARC web site. A simple command-line interface may be used to compress or uncompress any FITS image file.Comment: 20 pages, 9 figures, to be published in PAS