Water hyacinth infestation: nuisance or nugget

(11 page document

Using simulations and artificial life algorithms to grow elements of construction

'In nature, shape is cheaper than material', that is a common truth for most of the plants and other living organisms, even though they may not recognize that. In all living forms, shape is more or less directly linked to the influence of force, that was acting upon the organism during its growth. Trees and bones concentrate their material where thy need strength and stiffness, locating the tissue in desired places through the process of self-organization. We can study nature to find solutions to design problems. That’s where inspiration comes from, so we pick a solution already spotted somewhere in the organic world, that closely resembles our design problem, and use it in constructive way. First, examining it, disassembling, sorting out conclusions and ideas discovered, then performing an act of 'reverse engineering' and putting it all together again, in a way that suits our design needs. Very simple ideas copied from nature, produce complexity and exhibit self-organization capabilities, when applied in bigger scale and number. Computer algorithms of simulated artificial life help us to capture them, understand well and use where needed. This investigation is going to follow the question : How can we use methods seen in nature to simulate growth of construction elements? Different ways of extracting ideas from world of biology will be presented, then several techniques of simulated emergence will be demonstrated. Specific focus will be put on topics of computational modelling of natural phenomena, and differences in developmental and non-developmental techniques. Resulting 3D models will be shown and explained

Desire to change one's multimodality and its relationship to the use of different transport means

Using data collected from French employees of a transportation institute and residents of the US San Francisco Bay Area, we operationalize a segmentation of mobility patterns based on objective, subjective, and desired amounts of mobility by various modes and overall. We especially focus on the degree of multimodality in an individual's current modal mix and desired changes to that mix through the use of a "multimodality index". The clusters that result showed some similarities and some differences across countries, where the latter are likely due to disparities in the sampling strategies and in the land use/transportation/cultural milieux. In both cases, however, the clusters have useful policy implications, enabling us, for example, to distinguish car users who might be inclined to reduce car use and increase transit use from those who are largely content with their current modal basket

Single artificial wetland successfully treats different types of wastewater

The world's first full-scale artificial wetland designed to treat both sewage effluent and mine wastewater has been found to continuously remove high levels of pollutants, a recent study concludes. Treating both types of wastewater at the same time proved to be highly beneficial because they contain pollutants which are more easily removed when mixed together

Baseline groundwater chemistry : the Sherwood Sandstone of Devon and Somerset

This report describes the regional geochemistry of groundwater from the Sherwood Sandstone aquifer of Devon and Somerset. In order to assess the likely natural baseline chemistry of the groundwater in the area, information has been gathered from the strategic collection of 21 new groundwater samples, and from collation of existing groundwater, rainfall, mineralogical and geochemical data. The Sherwood Sandstone aquifer results from continental deposition during the early Triassic period. The deposition comprised thick clastic deposits in basins created during the late Permian. There are two distinct units: the Otter Sandstone Formation and the underlying Budleigh Salterton Pebble Beds Formation. These units form the most important aquifer in south-west England. The main chemical properties of the groundwater are determined by rainwater recharge reacting with the aquifer minerals. Of these minerals carbonates are the dominant influence on the water chemistry. While Ca is dominant in groundwaters from both aquifer units, the water types from the two units can be distinguished: the Otter Sandstone Formation aquifer has mainly Ca-HCO3 type waters, with some mixing towards Mg, and the groundwaters in the Budleigh Salterton Pebble Beds Formation aquifer are of Ca-HCO3 type to Na+K-Cl type. There is little variation in the major ion proportion of the groundwaters from the Otter Sandstone Formation, most likely as these represent groundwater in equilibrium with the minerals which give it this character. There is greater variation in the Budleigh Salterton Pebble Beds Formation groundwaters. Besides the difference in groundwater types, the groundwater from the Budleigh Salterton Pebble Beds Formation is more acidic, more oxic, has lower SEC values, and HCO3, Cr, U and Mg concentrations, and higher concentrations of Al, Be, Cd, Cr, Co, Tl and REE than the groundwater from the Otter Sandstone Formation. Human impacts on the water quality are evident. These are mainly visible in the presence of indicator contaminants, such as nitrate. The widespread presence and changes of nitrate concentrations over time indicate the extent to which the unconfined aquifer is influenced by modern farming practices or urban pollution. Concentrations of NO3-N exceeded the current drinking water limit of 11.3 mg L-1 in 25% of the sampled groundwaters, which probably reflects the intensification of agriculture in the study area over the last few decades. Indeed, the dominant land uses of the area are agriculture and grassland. However, recent legislation and the drive towards intelligent farming have meant that in some groundwaters the concentrations of nitrate are decreasing. While many of the groundwaters investigated in this study are of good inorganic quality there are some notable exceptions which contain elevated concentrations of Fe, SO4, Ni, Co and NO3. The distribution of the poor-quality is generally so sporadic that water quality would be difficult to predict prior to drilling a borehole. For many analytes, the 95th percentile of the distributions has been taken as a first approximation of an upper limit of baseline concentrations as this serves to eliminate the most extreme outlier concentrations that likely represent a distinct population

A mechanism for symmetry breaking in antiferromagnetic Heisenberg systems

An approximation method, based on dimer coverings, for the ground state of the antiferromagnetic Heisenberg lattice is described. The working of the method is demonstrated by some small-system calculations. The method introduces a possible mechanism for symmetry breaking for two- and higher-dimensional systems

Exact spectrum for n electrons in the single band Hubbard model

The energy spectrum and the correlation functions for n electrons in the one-dimensional single band Hubbard model with periodic boundary conditions are calculated exactly. For that purpose the Hamiltonian is transformed into a set of Hamiltonians, corresponding to systems of spinless fermions.\ud Our results include the results of Mei and Chen, presented in a recent paper

Can you take the heat? – Geothermal energy in mining

In 2013, there are less than 20 documented examples of operational geothermal systems on mine sites worldwide. This is surprising, since on remote mine sites, where fuels may have to be shipped in over great distances, heating and cooling from low-enthalpy geothermal sources may have a significant advantage in operational cost over conventional energy sources. A review of factors affecting the feasibility of geothermal systems on mining projects has been undertaken, and has identified the possible configurations of geothermal systems suitable for the exploration, operational and closure phases of mine development. The geothermal opportunities associated with abandoned or legacy mines are also discussed. The potential categories of heat reservoirs associated with mine sites are: natural ground; backfilled workings; mine waste; dewatering pumping; and flooded workings/pit lakes. The potentially lower operational costs for heating and cooling must be offset against the capital cost of a geothermal system. The focus for mine operators should therefore be on identifying at feasibility stage those projects where conditions are favourable for geothermal systems, the potential risks are understood, the economics are likely to be beneficial, and geothermal systems can be established while minimising additional capital costs

Mussel eggs as indicators of mutagen exposure in coastal and estuarine environments

The aim of this study was to develop a short-term genotoxicity assay for monitoring the marine environment for mutagens. Based on the developing eggs and embryos of the marine mussel Mytilus edulis, an important pollution indicator species, the test employs the sensitive sister chromatid exchange (SCE) technique as its end-point, and exploits the potential of mussel eggs to accumulate mutagenic pollutants from the surrounding sea water. Mussel eggs take up to 6 months to develop while in the gonad, which provides scope for DNA damage to be accumulated over an extended time interval; chromosome damage is subsequently visualised as SCEs in 2-cell-stage embryos after these have been spawned in the laboratory. Methods which measure biological responses to pollutant exposure are able to integrate all the factors (internal and external) which contribute to the exposure. The new cytogenetic assay allows the effects of adult exposure to be interpreted in cells destined to become part of the next generation

Elementary excitations in antiferromagnetic Heisenberg systems

The structure of the (eigen)states of antiferromagnetic Heisenberg systems is discussed. These systems are shown to be equivalent to classical systems of coupled harmonic oscillators. Most attention will be paid to the first excited state. This state is supposed to be a triplet. An approximation method, which is a generalization of a method, used to describe the ground state of Heisenberg systems, will be used to describe elementary excitations. The working of the method is demonstrated by some small-system calculations