19 research outputs found
Impacts of Waste from Concentrated Animal Feeding Operations on Water Quality
Waste from agricultural livestock operations has been a long-standing concern with respect to contamination of water resources, particularly in terms of nutrient pollution. However, the recent growth of concentrated animal feeding operations (CAFOs) presents a greater risk to water quality because of both the increased volume of waste and to contaminants that may be present (e.g., antibiotics and other veterinary drugs) that may have both environmental and public health importance. Based on available data, generally accepted livestock waste management practices do not adequately or effectively protect water resources from contamination with excessive nutrients, microbial pathogens, and pharmaceuticals present in the waste. Impacts on surface water sources and wildlife have been documented in many agricultural areas in the United States. Potential impacts on human and environmental health from long-term inadvertent exposure to water contaminated with pharmaceuticals and other compounds are a growing public concern. This work-group, which is part of the Conference on Environmental Health Impacts of Concentrated Animal Feeding Operations: Anticipating HazardsâSearching for Solutions, identified needs for rigorous ecosystem monitoring in the vicinity of CAFOs and for improved characterization of major toxicants affecting the environment and human health. Last, there is a need to promote and enforce best practices to minimize inputs of nutrients and toxicants from CAFOs into freshwater and marine ecosystems
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Sensing and actuation of smart chiral honeycombs
A novel concept of auxetic (negative Poissonâs ratio) honeycomb for active microwave absorbers and structural health monitoring applications has been developed within the European FP6 project CHISMACOMB (CHIral SMArt honeyCOMB). The honeycomb concept is made of tessellating cylinders and joining ligaments to form a noncentresymmetric structure, with PMC devices embedded in the core. The honeycomb features a negative Poissonâs ratio effect, synclastic curvature, enhanced compressive strength properties and sensing and actuation characteristics because of the piezo elements embedded. A tetrachiral demonstrator is developed and manufactured, subjected to dynamic testing (modal analysis). The response of the piezosensors under broadband white noise excitation is measured to evaluate the sensing capabilities of the honeycomb. Actuation authority is probed using progressive voltage loading. Numerical models are developed to simulate the piezoelectric response of the smart honeycombs and their mechanical performance