A critical look at residential electricity conservation campaigns in a developing country environment

This paper analyses survey results of the effectiveness of information campaigns to promote energy efficiency among residential consumers in Brazil. The survey found that consumers have a relatively good knowledge of conservation measures to improve electricity usage. Nevertheless, other approaches are needed to promote energy conservation in the household sector.     

CRITICAL EVALUATION OF CERTAIN METHODS OF UNSTEADY GROUNDWATER HYDRAULICS1

The basic theories and fundamental assumptions usually employed in the solution of unsteady groundwater flow problems are reviewed critically. The best known method of analysis for such problems is based on the Dupuit-Forchheimer approximation and leads to a nonlinear parabolic differential equation which is generally solved by linearization or numerical methods. The accuracy of the solution to this equation can be improved by use of a different approach which does not employ the Dupuit Forchheimer assumption, but rather is based on a semi-numerical solution of the Laplace equation for quasi-steady conditions. The actual unsteady process is replaced by a sequence of steady-state conditions, and it is assumed that the actual unsteady flow characteristics during a short time interval can be approximated by those associated with “average” steady state flow. The Laplace equation is solved by a semi-discretization method according to which the horizontal coordinate is divided into subintervals, while the vertical coordinate is maintained continuous. The proposed method is applied to a typical tile drainage problem, and, based on a comparison of calculated results with experimental data, the method is evaluated and practical conclusions regarding its applicability are advanced.     

Miscibility and Biodegradability of Poly(Butylene Succinate)/Poly(Butylene Terephthalate) Blends

As one of the biodegradable polymers, the blend of poly(butylene succinate) and poly(butylene terephthalate) is dealt with in this study. In our previous work, it was demonstrated that PBS and PBT are immiscible not only from the changes of T _g but also from logG–log G plots. It is expected that the biodegradability of the blends could be improved by enhancing the miscibility. We tried to induce the transesterification reaction between two polyesters with various time intervals to enhance the miscibility of the blends. The extent of transesterification reaction was examined by ¹H-NMR. We utilized a dynamic mechanical thermal analyzer and a rotational rheometer to investigate the changes in miscibility. We also verified the biodegradability of PBS/PBT blends after the transesterification reaction by the composting method.     

Prediction of syngas quality for two-stage gasification of selected waste feedstocks

This paper compares the syngas produced from methane with the syngas obtained from the gasification, in a two-stage reactor, of various waste feedstocks. The syngas composition and the gasification conditions were simulated using a simple thermodynamic model. The waste feedstocks considered are: landfill gas, waste oil, municipal solid waste (MSW) typical of a low-income country, the same MSW blended with landfill gas, refuse derived fuel (RDF) made from the same MSW, the same RDF blended with waste oil and a MSW typical of a high-income country. Energy content, the sum of H2 and CO gas percentages, and the ratio of H2 to CO are considered as measures of syngas quality. The simulation shows that landfill gas gives the best results in terms of both H2+CO and H2/CO, and that the MSW of low-income countries can be expected to provide inferior syngas on all three quality measures. Co-gasification of the MSW from low-income countries with landfill gas, and the mixture of waste oil with RDF from low-income MSW are considered as options to improve gas quality.     

Nitrogen cycling through swine production systems: ammonia, dinitrogen, and nitrous oxide emissions

Ammonia (NH(3)) emissions from animal systems have become a primary concern for all of livestock production. The purpose of this research was to establish the relationship of nitrogen (N) emissions to specific components of swine production systems and to determine accurate NH(3) emission factors appropriate for the regional climate, geography, and production systems. Micrometeorological instrumentation and gas sensors were placed over two lagoons in North Carolina during 1997-1999 to obtain information for determining ammonia emissions over extended periods and without interfering with the surrounding climate. Ammonia emissions varied diurnally and seasonally and were related to lagoon ammonium concentration, acidity, temperature, and wind turbulence. Conversion of significant quantities of ammonium NH(4)(+) to dinitrogen gas (N(2)) were measured in all lagoons with the emission rate largely dependent on NH(4)(+) concentration. Lagoon NH(4)(+) conversion to N(2) accounted for the largest loss component of the N entering the farm (43% as N(2)); however, small amounts of N(2)O were emitted from the lagoon (0.1%) and from field applications (0.05%) when effluent was applied nearby. In disagreement with previous and current estimates of NH(3) emissions from confined animal feeding operation (CAFO) systems, and invalidating current assumptions that most or all emissions are in the form of NH(3), we found much smaller NH(3) emissions from animal housing (7%), lagoons (8%), and fields (2%) using independent measurements of N transformation and transport. Nitrogen input and output in the production system were evaluated, and 95% of input N was accounted for as output N from the system.     

Cellular energy allocation in zebra mussels exposed along a pollution gradient: linking cellular effects to higher levels of biological organization

Organisms exposed to suboptimal environments incur a cost of dealing with stress in terms of metabolic resources. The total amount of energy available for maintenance, growth and reproduction, based on the biochemical analysis of the energy budget, may provide a sensitive measure of stress in an organism. While the concept is clear, linking cellular or biochemical responses to the individual and population or community level remains difficult. The aim of this study was to validate, under field conditions, using cellular energy budgets [i.e. changes in glycogen-, lipid- and protein-content and mitochondrial electron transport system (ETS)] as an ecologically relevant measurement of stress by comparing these responses to physiological and organismal endpoints. Therefore, a 28-day in situ bioassay with zebra mussels (Dreissena polymorpha) was performed in an effluent-dominated stream. Five locations were selected along the pollution gradient and compared with a nearby (reference) site. Cellular Energy Allocation (CEA) served as a biomarker of cellular energetics, while Scope for Growth (SFG) indicated effects on a physiological level and Tissue Condition Index and wet tissue weight/dry tissue weight ratio were used as endpoints of organismal effects. Results indicated that energy budgets at a cellular level of biological organization provided the fastest and most sensitive response and energy budgets are a relevant currency to extrapolate cellular effects to higher levels of biological organization within the exposed mussels.     

Development and validation of a method for analysis of "dioxin-like" PCBs in environmental samples from the steel industry

A method, previously used for determination of 2,3,7,8-substituted polychlorinated dibenzo-p-dioxins (PCDDs) and polychlorinated dibenzofurans (PCDFs), has been modified for quantitative analysis of "dioxin-like" polychlorobiphenyls (PCBs) in environmental samples from the steel industry. The existing sample clean-up procedure, involving liquid chromatography on multi-layered silica and Florisil columns, has been extended to include a third chromatography stage on a basic alumina stationary phase. The additional clean-up stage is required for PCB analysis in order to eliminate interferences from relatively large concentrations of saturated cyclic and aliphatic hydrocarbons. Samples were analysed for WHO-12 congeners using high resolution gas chromatography/high resolution mass spectrometry (HRGC/HRMS) and standard solutions of the method US EPA 1668A. Replicate analysis of method blanks revealed background contamination for PCBs 118, 105 and 77, which are generally abundant in ambient air. These contaminants were taken into account using a subtraction method. The entire procedure was validated by replicate analysis (N = 3) of a certified reference sediment. The RSD for each WHO-12 congener was below 15%, 13C12-labelled PCB internal standard recoveries were in the range 70-95%. A waste dust sample collected in the electrostatic precipitator of a UK sinter plant was analysed for determination of PCDD/Fs and WHO-12 PCBs and exhibited a PCDD/F I-TEQ of 148.5 +/- 21.2 ngkg(-1) and a WHO-TEQ of 7.2 +/- 1.5 ngkg(-1). WHO-12 congeners contributed only 4.6% to the overall TEQ and PCB 126 was the major congener contributing to the WHO-TEQ (96%). The contribution to the overall TEQ of the waste dust sample was mainly attributed to PCDF followed by PCDD, which accounted for 86.6% and 8.7% to the overall TEQ, respectively.     

Geomorphological evolution and environmental reclamation of Fusaro Lagoon (Campania Province, southern Italy)

Analysis of morphological, geological and environmental characteristics of the Fusaro Lagoon has shown the present degraded condition of the lagoon and the perilagoon area. The lagoon developed during the mid-Holocene within a wide marine bay confined between the coastal volcanic structures of Mt. Cuma to the north and Torregaveta to the south in the western part of the Phlegrean Fields. Subsequently, the bay was gradually filled with pyroclastic materials from phlegrean eruptive vents and sediments carried by the rivers Volturno and Clanis, thus, creating an open lagoon. It then evolved into a partially closed lagoon due to the formation of a continuous littoral spit during the late Holocene, probably wider than the present-day one and surrounded by marshlands. Finally, the total closure of the lagoon took place in the Graeco-Roman period, following the stabilization of the dune ridge, and it assumed a shape similar to present-day one only towards the end of the 18th century.Between the Roman period and 1941, three lagoon channels were opened in order to avoid the frequent environmental crises which continue to affect, although for different reasons, this salt-water basin. The basin has been exploited for more than 2000 years not only for mollusc culture and pisciculture, but also for the maceration of hemp and flax. In the 1980s, in order to reduce the effects of the environmental crises, dredging of the lagoon bottom has been carried out, altering the hydrogeological equilibrium and that of the ecosystem. Over the past 30 years, the supply of raw sewage of domestic, agricultural and industrial origin has ensured the presence of a high concentration of pollutants, including heavy metals.On the basis of the data obtained and in order to restore this sensitive transitional environment, eco-compatible interventions are proposed which aim at morphological and hydrologic resettlement, abatement of pollutants on the bottom of the basin, reintroduction of endemic molluscs, together with monitoring the quality of sediments and both sea-lagoon waters and groundwater.     

137Cs contamination in tea and yerba mate in South America

Gamma-ray spectra from more than 50 samples of food products available in stores of Buenos Aires city were measured using a germanium detector. Activity concentrations of 137Cs up to 10 Bq/kg were found in tea and yerba mate manufactured in Apóstoles, Argentina. Further measurements of tea leaves, yerba mate leaves and soils, all coming from a cultivated area in that region, also show the presence of 137Cs contamination. The results suggest that the area was fertilized with a product that originated in a region affected by the fallout from the Chernobyl nuclear plant accident.