Briquetting of charcoal from sugar-cane bagasse fly ash (scbfa) as an alternative fuel

Brazil is the largest worldwide producer of alcohol and sugar from sugar-cane and has an extensive alternative program for car fuel which is unique. The objective of this work is to offer one management option of a solid residue produced by this industrial segment. The pressed sugar-cane bagasse is burned to produce steam and electricity by cogeneration. The combustion yields both bottom and fly ashes which contain high amounts of silicon oxide as a major component. Fly ash which contains a high volume (>30% by weight) of charcoal was used in this work. The ash was sieved to separate the thick charcoal from inorganic materials which are concentrated in the thinner fraction. The briquettes were hand pressed using charcoal mixed with a binder (starch) obtained from cassava flour (a tropical root). The results (density, mechanical resistance) obtained with 8% by weight of starch binder are presented here. Thermogravimetric analysis (TGA) and differential scanning calorimetry (DSC) were used to characterize the ashes and the briquettes. The results show that sugar-cane bagasse fly ash (SCBFA) can be used to produce briquettes with an average density of 1.12 g cm^?3 and an average calorific value of 25,551 kJ/kg.     

Lateral movement of soil fumigants 1,3-dichloropropene and chloropicrin from treated agricultural fields

The soil fumigants 1,3-dichloropropene (1,3-D) and chloropicrin (CP) are often used for controlling soil-borne plant pathogens and parasitic nematodes before reestablishing new vineyards and orchards. To evaluate crop safety and environmental risks with the replant fumigation, four field experiments were performed over 2 yr to examine 1,3-D and CP lateral movement away from the treated fields. Shank injection with or without a virtually impermeable film (V1F) was used in two vineyard fumigation experiments, and spot drip application without tarp cover was used in two orchard experiments. Results showed that 1,3-D and CP gases moved laterally to 6 m from the treated fields when the fumigants were applied by shank injection. The maximum 1,3-D or CP soil gas concentration at 6 m was approximately 10 ng cm(-3) when the fumigated plot was not cover with a tarp. With VIF, the measured maximum concentration increased to approximately 100 ng cm(-3). In the spot drip application, maximum 1,3-D and CP gas concentrations reached approximately 100 ng cm(-3) but at 1.5 m radial distance from the point of fumigant injection.     

Quantifying trace gas emissions from composite landscapes: A mass-budget approach with aircraft measurements

Quantifying trace gas emissions and the influence of surface exchange processes on the atmosphere is a necessary step towards the control of global greenhouse gas emissions and reliability of air quality models. This paper proposes a procedure based on the mass balance method and implemented on highly resolved aircraft data. It allows one to estimate surface exchanges on areas of several km² and heterogeneous features exploiting the characteristics of convective boundary layer during steady state conditions that permit the estimation of emission/absorption terms as functions of advective fluxes only. A nonparametric approach is adopted and the fluxes on the surface of a virtual box surrounding the area of interest are reconstructed on the basis of scalar densities and wind vectors using Shepard functions. Two different techniques are also proposed to face lack of data on the top surface of the box. The method has been applied to experimental data coming from measurement campaigns on two different sites. It provides realistic estimates of the CO₂ emission/absorption in the considered areas that are in good agreement with CO₂ fluxes evaluated by Airborne Eddy Covariance and confirm the suitability of the proposed approach for the assessment of turbulent exchange of trace gases by composite landscapes. Uncertainties on the estimated emissions due to both propagation of the experimental error and interpolation have been quantified by bootstrap analysis as 6%.     

The relative influence of nutrients and habitat on stream metabolism in agricultural streams

Stream metabolism was measured in 33 streams across a gradient of nutrient concentrations in four agricultural areas of the USA to determine the relative influence of nutrient concentrations and habitat on primary production (GPP) and respiration (CR-24). In conjunction with the stream metabolism estimates, water quality and algal biomass samples were collected, as was an assessment of habitat in the sampling reach. When data for all study areas were combined, there were no statistically significant relations between gross primary production or community respiration and any of the independent variables. However, significant regression models were developed for three study areas for GPP (r ² = 0.79–0.91) and CR-24 (r ² = 0.76–0.77). Various forms of nutrients (total phosphorus and area-weighted total nitrogen loading) were significant for predicting GPP in two study areas, with habitat variables important in seven significant models. Important physical variables included light availability, precipitation, basin area, and in-stream habitat cover. Both benthic and seston chlorophyll were not found to be important explanatory variables in any of the models; however, benthic ash-free dry weight was important in two models for GPP.     

The reliability of experts' opinions in constructing a composite environmental index: The case of ESI 2005

The complexity of the environment demands a well-constructed composite environmental index (CEI) to provide a useful tool to draw attention to environmental conditions and trends for policy purposes. Among the common difficulties in constructing a proper CEI are uncertainties due to the selection of the most representative underlying variables or indicators. A degree of uncertainty accompanies experts' judgments, and to deal with vague, subjective or inconsistent information, logic other than classic is required. This study analyzes a procedure that uses different experts' opinions in constructing a CEI, with the use of paraconsistent annotated logic. For this, a sensitivity analysis of the Environmental Sustainability Index (ESI 2005) was used as an example to assess the reliability of experts' opinions. The uncertainty due to the disagreement in experts' opinions clearly indicates that the forms we presently use to measure and monitor the actual environment are insufficient, that is, there is a lack of a “science of sustainability”.     

Modelling Temperature Trends in New Zealand

If global warming is accelerating, then one might expect temperatures for most stations to be accelerating and perhaps variability to be increasing. In this study, we examine 57 New Zealand temperature time series for evidence of non-linearity and changing variability. These correspond to time series for annual minima, annual means and annual maxima for 19 stations. Estimation is by an extended least-squares method. We find a surprising diversity of behaviour of these series – presumably reflecting their different geographic factors as well as series length. We give evidence of regions where temperatures are decreasing. For series where a linear trend is significant, it is downwards in about one third of the cases. This proportion was higher in the South Island, especially for series of minima. Where a non-linear trend is significant, temperatures are decelerating in about one half of the cases. The ratio of downward to upward trends is highest among annual maxima and South Island minima and smallest in annual means. Where a linear trend in the variability is significant, it is decreasing in 13 cases and increasing in 5 cases, although possibly this is partly due to poorer quality data last century. Where a non-linear trend in the variability is significant, variability is decelerating in about two thirds of the cases. The results are used to project upper and lower return levels of minima, means and maxima for each of the series to the year 2010.     

Analysis of arable land loss and its impact on rural sustainability in Southern Jiangsu Province of China

Rapid urbanization and industrialization in southern Jiangsu Province have consumed a huge amount of arable land. Through comparative analysis of land cover maps derived from TM images in 1990, 2000 and 2006, we identified the trend of arable land loss. It is found that most arable land is lost to urbanization and rural settlements development. Urban settlements, rural settlements, and industrial park-mine-transport land increased, respectively, by 87 997 ha (174.65%), 81 041 ha (104.52%), and 12 692 ha (397.99%) from 1990 to 2006. Most of the source (e.g., change from) land covers are rice paddy fields and dryland. These two covers contributed to newly urbanized areas by 37.12% and 73.52% during 1990–2000, and 46.39% and 38.86% during 2000–2006. However, the loss of arable land is weakly correlated with ecological service value, per capita net income of farmers, but positively with grain yield for some counties. Most areas in the study site have a low arable land depletion rate and a high potential for sustainable development. More attention should be directed at those counties that have a high depletion rate but a low potential for sustainable development. Rural settlements should be controlled and rationalized through legislative measures to achieve harmonious development between urban and rural areas, and sustainable development for rural areas with a minimal impact on the ecoenvironment.