Using Landsat Imagery to Analyse Land Cover Change in the Njoro Watershed, Kenya

In developing nations where resources are scarce and increased population pressures create stress on available resources, methods are needed to examine effects of human migration and resultant changes in land cover. Widespread availability and low cost of remotely sensed imagery and Geographic Information Systems (GIS) are making such methods a reality to develop quantitative resource mapping and land cover change detection in developing nations (Sheng et al., 1997). However, difficulties arise in tropical regions when trying to analyse traditional vegetation bands (Bands 3 and 4), or indices such as NDVI because saturated pixels limit spectral distinction

Transition phenomena in unstably stratified turbulent flows

We study experimentally and theoretically transition phenomena caused by the external forcing from Rayleigh-Benard convection with the large-scale circulation (LSC) to the limiting regime of unstably stratified turbulent flow without LSC whereby the temperature field behaves like a passive scalar. In the experiments we use the Rayleigh-B\'enard apparatus with an additional source of turbulence produced by two oscillating grids located nearby the side walls of the chamber. When the frequency of the grid oscillations is larger than 2 Hz, the large-scale circulation (LSC) in turbulent convection is destroyed, and the destruction of the LSC is accompanied by a strong change of the mean temperature distribution. However, in all regimes of the unstably stratified turbulent flow the ratio $\big[(\ell_x \nabla_x T)^2 + (\ell_y \nabla_y T)^2 + (\ell_z \nabla_z T)^2\big] /$ varies slightly (even in the range of parameters whereby the behaviour of the temperature field is different from that of the passive scalar). Here $\ell_i$ are the integral scales of turbulence along x, y, z directions, T and \theta are the mean and fluctuating parts of the fluid temperature. At all frequencies of the grid oscillations we have detected the long-term nonlinear oscillations of the mean temperature. The theoretical predictions based on the budget equations for turbulent kinetic energy, turbulent temperature fluctuations and turbulent heat flux, are in agreement with the experimental results.Comment: 14 pages, 14 figures, REVTEX4-1, revised versio

Impact of Land Use on Water Quality in River Njoro Watershed, Kenya

Water resources within the River Njoro watershed have become degraded due to high population growth rate and change in land use upsetting environmental stability. Land cover classification using Landsat images (Baldyga et al., 2004) shows loss of about 20% of forested areas between 1986 and 2003 in the watershed. The forested and large-scale farm areas have been converted mainly into small-scale mixed agriculture and human settlements. These changes have impacted negatively on the ecological integrity and hydrologic processes in the watershed (Shivoga, 2001) but little is known about the influence of specific land uses on water quality of the river

Biodegradation pretreatment of wood of E. grandis, E. dunnii, and E. benthamii to work in biorefinery processes

Nowadays, there is a great interest in using lignocellulosic materials as substrate for the production of biorefi nery products. Eucalypti are good options to use as crops to obtain different kinds of biofuels and derivatives, since their plantations show high adaptation potential to soil and weather conditions in Uruguay. The basic process steps involved in the obtainment of biorefi nery materials are: pretreatment, hydrolysis, fermentation and products separation. As delignifi cation is an important process to obtain biorefi nery products, in this context the evaluation of the biological (BT) and hydrothermal (TT) pretreatment of different species of Eucaliptus was studied. The possibility of obtaining sugars, alcohols and organic acids was the main focus. The results of these investigations show a good production of reducing sugars (4-5 mg/mL for both BT and TT pretreatments), acetic acid (3-8 mg/mL for BT and 3-7 mg/mL for TT) and isopropanol (18-48 mg/mL for BT and 20-30 mg/mL for TT). In conclusion, the results show similar behaviours for BT and TT pretreatments, which is a quite important result since BT is cheaper and cleaner and thus a more attractive technology

Review: The Journal of Dramaturgy, volume 23, issue 2

Contents include: Editor\u27s Note; LMDA Conference 2013 Re-defining Risk, A Keynote Address; Ellliott Hayes Award for Outstanding Achievement in Dramaturgy Introduction; Ellliott Hayes Award for Outstanding Achievement in Dramaturgy Staging Latina/o Classrooms and Culture: DNA and Dangerous Dramaturgy at the U.S.-Mexico Border; Early Career Dramaturgs Envision the Future of Dramaturgy: An Ensemble-Created Manifesto; What is the Future of Dramaturgy? A Manifesto; Juan Radigan and the Gringo, or Why Chilean Theatre Deserves our Attention; Behind the Scenes in Bollywood: An Interview with Brian Quirt; National Theatre: Center Stage\u27s My America Project; Crowdsourcing a New Hamburg Dramaturgy, A Preview of The Hamburg Dramaturgy: A New & Complete English Translation. Issue editors: Sydney Cheek-O\u27Donnell, Debra Cardona, Janine Sobeckhttps://soundideas.pugetsound.edu/lmdareview/1046/thumbnail.jp

Statistical description of the bubble cloud resulting from the injection of air into a turbulent water jet

The final bubble size distribution, resulting from the break-up of an air jet injected into the central axis of a fully developed, high Reynolds number turbulent water jet has been measured using a Phase Doppler Particle Analyzer (PDPA). The shape of the final size distribution is shown to depend not only on the dissipation rate of turbulent kinetic energy, ε, but also on the global void fraction, αH. It has been shown that such a dependence can be expressed as a function of two dimensionless numbers, namely the jet Weber number, Wen=ρUJ2DJ/σ, and the ratio between the initial bubble's size and the critical diameter, D0/Dc. The statistical properties of the time and distance separating two bubbles of the same diameter, after the turbulent break process is complete, have also been measured. The probability density function of the inter-arrival time between two consecutive bubbles was found to follow an exponential distribution with intensity factor, λ, depending on the number density of bubbles of a certain diameter and on the velocity of the flow

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