Utilising biological geotextiles: Introduction to the BORASSUS project and global perspectives

Field and laboratory studies indicate that utilisation of biological geotextiles constructed from palm-leaves and other selected organic materials are an effective, sustainable and economically viable soil conservation technique. The three-year plus (1 July 2005–28 February 2009) EU-funded BORASSUS Project (contract no. INCO-CT-2005-510745) evaluated the long-term effectiveness of biological geotextiles in controlling soil erosion and assessing their sustainability and economic viability. These studies progressed in ten countries, both in the ‘industrial north’ (in Europe) and in the ‘developing south’ (Africa, South America and South East Asia). The studied countries in the ‘developing south’ included Brazil, China, The Gambia, South Africa, Thailand and Vietnam. The ‘industrial north’ countries included Belgium, Hungary, Lithuania and the UK. The main findings of these studies are summarised in this paper and thematic information is presented in the other four papers in this Special Issue. Biological geotextiles offer potentially novel bioengineering solutions to environmental problems, including technologies for soil conservation, sustainable plant production and use of indigenous plants, improved ecosystem management by decreasing deforestation, improving agroforestry and cost-effective biogeotextile applications in diverse environments. Biogeotextiles may provide socio-economic platforms for sustainable development and the benefits for developing countries may include poverty alleviation, engagement of local people as stakeholders, employment for disadvantaged groups, small and medium enterprise (SME) development, earning hard currency, environmental education and local community involvement in land reclamation and environmental education programmes. These benefits are achieved through: (i) promotion of sustainable and environmentally friendly palm-agriculture to discourage deforestation, promoting both reforestation and agroforestry; (ii) construction of biogeotextiles enabling development of a rural labour-intensive industry, particularly encouraging employment of socially disadvantaged groups and (iii) export of biogeotextiles to industrialised countries could earn hard currency for developing economies, based on the principles of fair trade. Research and development activities of the BORASSUS Project have improved our knowledge on the effect of biogeotextile mats on the micro- and macro-soil environments and at larger scales through controlled laboratory and field experiments in diverse environments

Rainfall simulator study of the erosion control potential of palm geotextiles for mine dam slope stabilization

Proceedings of the Green5 Conference, Vilnius, Lithuania 1 July - 4 July 2008Mining has been the backbone of the South African economy since the late 19th century. Large volumes of mine waste, such as tailings, have been generated in some areas. Mine waste is highly susceptible to both water and wind erosion, it may create moderate to severe chemical imbalances or toxicities and has a severe abrasive effect on seedlings, a low water-holding capacity and is prone to compaction and crusting. Biogeotextiles are potentially effective and economically-viable erosion control products. The main objective of the study reported herein was to establish the erosion control properties of palm-mats by determining erosion-related variables via rainfall simulation. The textiles were manufactured from the leaves of the Lala palm (Hyphaene coriacea) and covered about 40% of the tailing surface. Ten representative samples of South African mine waste materials were collected for the rainfall simulator studies. Measured erosion parameters included; runoff, sediment load in runoff and interrill erodibility. Seven samples were sand-textured and three were silty. Sediment load was not dependent on exchangeable sodium or organic matter contents, but prominently associated with pH, silt percentage and the quartz content in the clay fraction. When the samples were covered with palm-mats the amount of runoff was similar to that of bare materials, but sediment yield was reduced by about 55%. These results confirm the suitability of palm geotextiles for erosion control on tailing dam slopes

Active axial stress in mouse aorta

The study verifies the development of active axial stress in the wall of mouse aorta over a range of physiological loads when the smooth muscle cells are stimulated to contract. The results obtained show that the active axial stress is virtually independent of the magnitude of pressure, but depends predominately on the longitudinal stretch ratio. The dependence is non-monotonic and is similar to the active stress-stretch dependence in the circumferential direction reported in the literature. The expression for the active axial stress fitted to the experimental data shows that the maximum active stress is developed at longitudinal stretch ratio 1.81, and 1.56 is the longitudinal stretch ratio below which the stimulation does not generate active stress. The study shows that the magnitude of active axial stress is smaller than the active circumferential stress. There is need for more experimental investigations on the active response of different types of arteries from different species and pathological conditions. The results of these studies can promote building of refined constrictive models in vascular rheology. (C) 2012 Elsevier Ltd. All rights reserved