Approaches to Environmental Management: Aspects and Types Article shared by:
Approaches[ edit ] De-icing can be accomplished by mechanical methods scraping, pushing ; through the application of heat ; by use of dry or liquid chemicals designed to lower the freezing point of water various salts or brinesalcoholsglycols ; or by a combination of these different techniques.
Trains and rail switches[ edit ] Ice build up in train brakes jeopardizes braking efficiency. Trains and rail switches in arctic regions have large problems with snow and ice build up. They need a constant heat source in cold days to assure functionality.
On trains it is primarily the brakessuspension and couplers that require heaters for de-icing. On rails it is primarily the switches that are sensitive to ice.
These high-powered electrical heaters efficiently prevent ice formation and rapidly melt any ice that forms. The heaters are preferably made of PTC material, e.
PTC rubberto avoid overheating and potentially destroying the heaters. These heaters are self-limiting and require no regulating electronics; they cannot overheat and require no overheat protection. Gulfstream G gets de-iced before departing Alaska in January On the ground, when there are freezing conditions and precipitationde-icing an aircraft is crucial.
Frozen contaminants cause critical control surfaces to be rough and uneven, disrupting smooth air flow and greatly degrading the ability of the wing to generate liftand increasing drag.
This situation can cause a crash. If large pieces of ice separate when the aircraft is in motion, they can be ingested in engines or hit propellers and cause catastrophic failure. Frozen contaminants can jam control surfaces, preventing them from moving properly. In flight, droplets of supercooled water often exist in stratiform and cumulus clouds.
They form into ice when they are struck by the wings of passing airplanes and abruptly crystallize. This disrupts airflow over the wing, reducing lift, so aircraft that are expected to fly in such conditions are equipped with a de-icing system.
De-icing techniques are also employed to ensure that engine inlets and various sensors on the outside of the aircraft are clear of ice or snow. Chemical de-icing[ edit ] De-icing fluids consisting of propylene glycol PG and additives are widely used by airlines for de-icing aircraft.
However, PG is more common because it is less toxic than ethylene glycol. Even though PG is classified as non-toxic, it pollutes waterways since it consumes large amounts of oxygen as it decomposes, causing aquatic life to suffocate.
See Environmental impacts and mitigation. Anti-icing of aircraft is accomplished by applying a protective layer, using a viscous fluid called anti-ice fluid, over a surface to absorb the contaminant.
All anti-ice fluids offer only limited protection, dependent upon frozen contaminant type and prevailing weather conditions. A fluid has failed when it no longer can absorb the contaminant and it essentially becomes a contaminant itself.
Even water can be a contaminant in this sense, as it dilutes the anti-icing agent until it is no longer effective. Infrared heating de-icing[ edit ] Direct infrared heating has also been developed as an aircraft de-icing technique.
This heat transfer mechanism is substantially faster than conventional heat transfer modes used by conventional de-icing convection and conduction due to the cooling effect of the air on the de-icing fluid spray. One infrared de-icing system requires that the heating process take place inside a specially-constructed hangar.
This system has had limited interest among airport operators, due to the space and related logistical requirements for the hangar. In the United States, this type of infrared de-icing system has been used, on a limited basis, at two large hub airports and one small commercial airport.
However, urea is a significant pollutant in waterways and wildlife, as it degrades to ammonia after application, and it has been largely been phased out at U. In the U. Environmental Protection Agency EPA prohibited use of urea-based deicers at most commercial airports.
Sodium chloride rock salt is normally used, as it is inexpensive and readily available in large quantities. It also has a strong tendency to cause corrosionrusting the steel used in most vehicles and the rebar in concrete bridges. Depending on the concentration, it can be toxic to some plants and animals, and some urban areas have moved away from it as a result.
More recent snowmelters use other salts, such as calcium chloride and magnesium chloridewhich not only depress the freezing point of water to a much lower temperature, but also produce an exothermic reaction. They are somewhat safer for sidewalksbut excess should still be removed.
More recently, organic compounds have been developed that reduce the environmental issues connected with salts and have longer residual effects when spread on roadways, usually in conjunction with salt brines or solids.
These compounds are generated as byproducts of agricultural operations such as sugar beet refining or the distillation process that produces ethanol.Environmental Management Approaches Preliminary Summary of the Results of two Projects for the German Federal Environment Ministry and the.
Point-of-decision prompts were evaluated in a range of settings including shopping malls, train and bus stations, airports, an office building, a bank, a healthcare facility, a medical school, a .
The Community Preventive Services Task Force (CPSTF) recommends built environment strategies that combine one or more interventions to improve pedestrian or bicycle transportation systems with one or more land use and environmental design interventions to increase physical activity.
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Definition of ENVIRONMENTAL APPROACH: Identifying risks in the external environment, then conducting an. The Chronic Disease Prevention & Health Promotion Bureau coordinated environmental approaches page. It does this through the formulation of policy, coordinating and monitoring environmental issues, environmental planning and policy-oriented environmental attheheels.com National Environment Management Council (NEMC) is an institution that was initiated when the National Environment Management Act was first introduced in year
A critical resource for approaching sustainability across the disciplines Sustainability and social justice remain elusive even though each is unattainable without the other.
Across the industrialized West and the Global South. National Institute of Environmental Health Sciences | The mission of the NIEHS is to discover how the environment affects people in order to promote healthier lives.
Definition of ENVIRONMENTAL APPROACH: Identifying risks in the external environment, then conducting an.