Nitrogen cycle of effluent-irrigated energy crop plantations:from wastewater treatment to thermo-chemical conversion processes

This paper reviews nitrogen (N) cycle of effluent-irrigated energy crop plantations, starting from wastewater treatment to thermo-chemical conversion processes. In wastewater, N compounds contribute to eutrophication and toxicity in water cycle. Removal of N via vegetative filters and specifically in short-rotation energy plantations, is a relatively new approach to managing nitrogenous effluents. Though combustion of energy crops is in principle carbon neutral, in practice, N content may contribute to NOx emissions with significant global warming potential. Intermediate pyrolysis produces advanced fuels while reducing such emissions. By operating at intermediate temperature (500°C), it retains most N in char as pyrrolic-N, pyridinic-N, quaternary-N and amines. In addition, biochar provides long-term sequestration of carbon in soils.

Energy conservation measures on an industrial site

World and UK energy resources and use are reviewed and the role of energy conservation in energy policy identified. In considering various energy conservation measures, a distinction is made between energy intensive and non-intensive industries and also between direct and indirect uses of energy. Particular attention is given to the non-intensive user of energy. Energy use on one such industrial site has been studied to determine the most effective energy saving measures in the short term. Here it is estimated that over 65% of energy is consumed for indirect purposes, mainly for heating and lighting buildings. Emphasis is placed on energy auditing techniques and those energy saving measures requiring greater technical, economic and organisational resources to secure their implementation. Energy auditing techniques include the use of aerial thermography and snow formation surveys to detect heat losses. Qualitative and quantitative interpretations are carried out, but restricted mainly to evaluating building roof heat losses. From the energy auditing exercise, it is confirmed that the intermittent heating of buildings is the largest and most cost effective fuel saving measure. This was implemented on the site and a heat monitoring programme established to verify results. Industrial combined heat and power generation is investigated. A proposal for the site demonstrates that there are several obstacles to its successful implementation. By adopting an alternative financial rationale, a way of overcoming these obstacles is suggested. A useful by-product of the study is the classification of industrial sites according to the nature of industrial energy demand patterns. Finally, energy saving measures implemented on the site are quantlfied using comparative verification methods. Overall fuel savings of 13% are indicated. Cumulative savings in heating fuel amount to 26% over four years although heated area increased by approximately 25%.

Short- and long-term changes in corneal aberrations and axial length induced by orthokeratology in children are not correlated

PURPOSE: To assess the correlation between changes in corneal aberrations and the 2-year change in axial length in children fitted with orthokeratology (OK) contact lenses. METHODS: Thirty-one subjects 6 to 12 years of age and with myopia −0.75 to −4.00DS and astigmatism ≤1.00DC were fitted with OK. Measurements of axial length and corneal topography were taken at regular intervals over a 2-year period. Corneal topography at baseline and after 3 and 24 months of OK lens wear was used to derive higher-order corneal aberrations (HOA) that were correlated with OK-induced axial length changes at 2 years. RESULTS: Significant changes in C3, C4, C4, root mean square (RMS) secondary astigmatism and fourth and total HOA were found with both 3 and 24 months of OK lens wear in comparison with baseline (all P0.05). Coma angle of orientation changed significantly pre-OK in comparison with 3 and 24 months post-OK as well as secondary astigmatism angle of orientation pre-OK in comparison with 24 months post-OK (all P0.05). DISCUSSION: Short-term and long-term OK lens wear induces significant changes in corneal aberrations that are not significantly correlated with changes in axial elongation after 2-years.