Water logging

Water logging is the situation when the productivity of agricultural land gets affected by the high waterablity. Water logging results in ill-aeration of plants. Water logging also makes tilling and ploughing processes difficult. Water logging also leads to the growth of unwanted plants like grass, weeds etc. and affects the growth of the crops. Water logging is responsible for bacterial activity retardation. Water logging also leads to salinity of soils. A saline soil reduces osmotic activity of the plants. Thus crop yield is very much affected by water logging. Some important causes for water logging are intensive irrigation, seepage of water from the adjoining high lands, inadequate surface drainage, inadequate natural drainage, impervious obstruction, seepage of water through canals, irregular topography, submergence due to the floods and excessive rains. The important measures employed for water logging control are introduction of lift irrigation, reducing the intensity of irrigation, provision of intercepting drains, introduction of crop rotation, lining of canals, provision of an efficient drainage system, improving the natural drainage and optimum use of water.

Plastic deformation mechanisms in metals

The permanent changes in shape and dimensions of metals can be carried out by plastic deformation mechanisms. Crystal structure and lattice parameters remain unaltered during plastic deformation. Plastic deformation increases the number of imperfections in metals. The two main processes involved in plastic deformation are slip and twinning. In slip, atoms move over a number of interatomic distances relative to their initial positions. The displacement step magnitude is equal to full interatomic distance. The orientation of displaced region and undeformed region remains the same. Movement by an atom is a fraction of interatomic distance in twinning process. The orientation of twinned region and untwined regions are not same. Slip mechanism is preferred during high temperature and lower strain rate cases. At lower temperature, high strain rate cases, twinning is employed.

Nanobuds

Nanotechnology has already become an important field in the medical field for diagnostic and drug delivery applications. Carbon-60 molecules which are also known as fullerene promises good appliance in medical field. Cylindrical fullerenes are known as carbon nanotubes. Carbon nanotubes can be synthesized in many forms. Single walled nanotubes and multi walled nanotubes are two important materials. A carbon nanotubes bent into a torus is known as nanotorus. Carbon nanobuds are latest member in Nanomaterials category which is created by the combination of carbon nanotubes and fullerenes. Fullerene in the form of buds is connected to carbon nanotubes by covalent bonding in nanobuds. Bonding is achieved between fullerene buds and sidewalls of carbon nanotubes. The main application of nanobuds is in field emission applications since they are excellent field emitters. Since the fullerene buds prevents slipping of nanotubes, nanobuds can be used as molecular anchors.