Free Energy Definition in Science

Free Energy Definition in Science The phrase free energy has multiple definitions in science: Thermodynamic Free Energy In physics and physical chemistry, free energy refers to the amount of internal energy of a thermodynamic system that is available to perform work. There are different forms of thermodynamic free energy: Gibbs free energy is the energy that may be converted into work in a system that is at constant temperature and pressure. The equation for Gibbs free energy is: G H – TS where G is Gibbs free energy, H is enthalpy, T is temperature, and S is entropy. Helmholtz free energy is energy that may be converted into work at constant temperature and volume. The equation for Helmholtz free energy is: A U – TS where A is the Helmholtz free energy, U is the internal energy of the system, T is the absolute temperature (Kelvin) and S is the entropy of the system. Landau free energy describes energy of an open system in which particles and energy may be exchanged with the surroundings. The equation for Landau free energy is: ÃŽ © A - ÃŽ ¼N U - TS - ÃŽ ¼N where N is the number of particles and  ÃŽ ¼ is  chemical potential. Variational Free Energy In information theory, variational free energy is a construct used in variational Bayesian methods. Such methods are used to appoximate intractable integrals for statistics and machine learning. Other Definitions In environmental science and economics, the phrase free energy is sometimes used to refer to renewable resources or any energy that does not require monetary payment. Free energy may also refer to the energy that powers a hypothetical perpetual motion machine. Such a device violates the laws of thermodynamics, so this definition presently refers to a pseudoscience rather than hard science. Sources Baierlein, Ralph (2003). Thermal Physics. Cambridge University Press. ISBN 0-521-65838-1.Mendoza, E. (1988). Clapeyron, E.; Carnot, R., eds. Reflections on the Motive Power of Fire – and other Papers on the Second Law of Thermodynamics. Dover Publications, Inc. ISBN 0-486-44641-7.Stoner, Clinton D. (2000). Inquiries into the Nature of Free Energy and Entropy in Respect to Biochemical Thermodynamics.  Entropy Vol. 2.

Thing to Consider When Planting A Norway Maple

Thing to Consider When Planting A Norway Maple Norway maple (Acer platanoides) was introduced by botanist John Bartram of Philadelphia from England to the U.S. in 1756. It has been planted on farms and in towns for its shade, hardiness, and adaptability to adverse conditions, which has ensured that the maple, when planted, would spread like wildfire. Because of this, and a variety of other negative factors, the Norway maple has earned itself the title of a Bad Tree, meaning its destruction is often sought out by city governments and concerned landscapers fearing that the large canopy of leaves this particular maple yields will block all other growth underneath it. However, there is a number of redeeming qualities to this type of trees such as its tolerance to multiple types of soil nutrients and climate conditions, its optimal fall foliage, and beautiful yellow flowers in the spring. Why Norway Maples Are Bad Trees The shallow, fibrous root system and dense shade of Norway maple make it virtually impossible for grass to grow under the tree, and the aggressive roots frequently girdle even the parent tree, ultimately choking itself to death, making it a bad tree if youre planning on growing anything else around it. Further, Norway maples are also non-native invasive exotic trees that have escaped the urban environment and is a threat to native maples because of its sun-blocking foliage. Norway maple populations overwhelm sites by displacing native trees, shrubs, and herbaceous understory plants, and once established, creating a canopy of dense shade that prevents regeneration of native seedlings; it is also thought to release root toxins that inhibit or prevent the growth of other plants. Norway maples also reproduce quickly, forming dense root systems in a matter of seasons that are nearly impossible to fully remove without killing the surrounding soil entirely. However, this isnt to say there are no redeeming qualities for this type of tree. Redeeming Features Norway maples are arguably among the most beautiful variety of maple tree currently in North America with rich yellow leaves in the fall under optimal conditions and lovely yellow flowers on leafless branches in the spring. These trees are also highly resistant to climate conditions and lack of nutrition in the soil and can grow almost anywhere as a result, which makes them great for planting on land that usually cannot support much greenery. Also, due to their nature of spreading rapidly, harvesting new trees for distribution is surprisingly easy- just replant one of its many roots and a new tree will begin growing in no time. Plus, Norway maples grow rather quickly and provide lots of shade, so they can be used to generate a quick, natural privacy fence for your property.