Comparative moisture and heat sorption properties of fibre and shiv derived from hemp and flax

Abstract: Unlike many mineral-based insulation materials bio-based lignocellulosic fibre and shiv offer a number of benefits including thermal and hygroscopic properties. The microstructure, porosity and chemical compositions of the plant cell walls play a major role in the moisture exchange process. In this paper, the effects of microstructure, chemical composition, porosity and pore size distribution of both fibre and shiv, from hemp and flax plants, on both moisture and heat sorption were studied for the first time. The physical and chemical characteristics of the fibre and shiv from hemp and flax were studied by using scanning electron microscopy, mercury intrusion porosimetry and Fourier transform infrared spectroscopy. Water moisture sorption and heat of sorption were studied using a dynamic vapour sorption apparatus and a simultaneous thermal analysis system, combined with a humidity generator and using a copper furnace. Results showed that both the fibre and shiv of hemp and flax adsorbed a similar amount of moisture at a given relative humidity, which was dependent on the availability of hydroxyl groups for water in the cell wall. The macroscopic surface area and porosity of the specimen on a large scale had little influence on the availability of hydroxyl groups in the cell wall. The water molecules bound with cell wall molecules through hydrogen bonds over the full range of relative humidities, with a consistent hysteresis difference between the first sorption isotherm and subsequent sequential sorption cycles found in the hemp shiv specimens. For both hemp and flax, the isothermic hysteresis of the shiv was much higher than that of the fibre, which was shown to be dependent on the lignin content. The result of heat sorption indicated that some blocked sorption sites become available to water vapour molecules due to the change in molecular structure of the cell wall during the adsorption process. This study has improved understanding of the hemp and flax sorption behaviour and is important for optimal application of bio-based insulation materials for construction

Limeboo: Lime as a Replacement for Cement in Wall-Framing Systems with Bamboo-Guadua (Bahareque Encementado)

Traditional construction systems with the bamboo species Guadua angustifolia Kunth (Guadua) are standardized under the Colombian code for seismic-resistant buildings '1'. These systems are regarded as highly environmentally friendly due to their intensive use of Guadua in the supporting structure and walls. In particular, the plastered cane building system or 'bahareque encementado', which provides a low-cost and low-technology alternative for two-storey dwellings, commonly uses round Guadua for the frame and riven Guadua boards (esterilla) for covering the frame. However, this wall-framing system relies heavily on cement renders for providing combined structural action to resist lateral loads, protecting the material against weathering and ensuring a flat surface for construction finishes. Thick cement renders contribute greatly to the wall mass and together with the foundations result on the highest negative environmental impact in traditional wallframing construction with Guadua. Therefore, the reduction of the use of cement or its complete replacement for alternative binders in the wall-framing 'bahareque' system is a key point for environmental improvement. Widely available materials such as lime, which have less energy intensive production-processes present an alternative to cement. Moreover, lime offers improved breathability within the building and behaves more elastically than cement. This paper explores the potential use of lime as a replacement for cement mortars in 'bahareque' systems and analyses Guadua's anatomical and chemical features when mixed with lime. The paper describes a 'cold process' in which no high temperatures are involved for the improvement of the bonding between lime and bamboo

Oil baron of the Southwest: Edward L. Doheny and the development of the petroleum industry in California and Mexico

(print) x, 302 p. : ill., maps ; 24 cmBased on the author's doctoral dissertation, University of Texas at AustinAcknowledgments -- Introduction. p.1 -- 1. Early years in the West. p.7 -- 2. Oil and railroads in Southern California, 1892-1902. p.23 -- 3. The birth of the Mexican oil industry, 1900-1910. p.52 -- 4. Return to California, 1908-1912. p.87 -- 5. Creating an international oil company, 1912-1915. p.105 -- 6. The Pan American Petroleum & Transport Company, 1916. p.130 -- 7. The Vision of Peace: fuel oil for the war. p.147 -- 8. Promoting an oil policy for Mexico, 1917-1920. p.162 -- 9. Domestic politics and international relations: Ireland and Japan, 1920-1921. p.180 -- 10. Salt water and revolution: Mexico, 1921-1923. p.196 -- 11. The bark of political wolves: Doheny and the oil scandal. p.212 -- Conclusion. p.238 -- App. A. Production and sales of the Mexican and Huasteca Petroleum Companies, 1901-1914. p.245 -- App. B. Oil production and exports for the Mexican petroleum industry, 1916-1924. p.246 -- App. C. Companies owned and controlled by the Pan American Petroleum & Transport Company at its incorporation, 1916. p.250 -- App. D. Relative sizes of the largest American oil companies by total assets. p.252 -- Notes. p.253 -- Index. p.29