05-07-2012, 10:15 AM
Write a report on latest material being studied under nano-technology
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INTRODUCTION :-
Nanomaterials is a field that takes a materials science-based approach to nanotechnology. It studies materials with morphological features on the nanoscale, and especially those that have special properties stemming from their nanoscale dimensions. Nanoscale is usually defined as smaller than a one tenth of a micrometer in at least one dimension, though this term is sometimes also used for materials smaller than one micrometer.
On 18 October 2011, the European Commission adopted the following definition of a nanomaterial:
A natural, incidental or manufactured material containing particles, in an unbound state or as an aggregate or as an agglomerate and where, for 50% or more of the particles in the number size distribution, one or more external dimensions is in the size range 1 nm – 100 nm. In specific cases and where warranted by concerns for the environment, health, safety or competitiveness the number size distribution threshold of 50% may be replaced by a threshold between 1 and 50%.
TYPES OF NANOMATERIALS :-
In most cases, nanomaterials are broken down into two categories to include inorganic nanoparticles and fullerenes. First, nanoparticles, which are sometimes referred to as “nanocrystals” consist of oxides, metals, or semiconductors because of their optical, chemical, mechanical, electrical, and magnetic properties, among others. Because of their characteristics, nanoparticles are vital in bridging the gap between atomic or molecular structures and bulk materials. Second, the fullerenes class consists of allotropes of carbons, which usually include carbon nanotubes that are grapheme sheets rolled into sphere or tubes. Because of their incredible strength in electrical and mechanical arenas, fullerenes are extremely beneficial.
Nanoparticles and steel
Steel has been widely available material and has a major role in the construction industry. The use of nanotechnology in steel helps to improve the properties of steel. The fatigue, which led to the structural failure of steel due to cyclic loading, such as in bridges or towers.The current steel designs are based on the reduction in the allowable stress, service life or regular inspection regime. This has a significant impact on the life-cycle costs of structures and limits the effective use of resources.The Stress risers are responsible for initiating cracks from which fatigue failure results .The addition of copper nanoparticles reduces the surface un-evenness of steel which then limits the number of stress risers and hence fatigue cracking. Advancements in this technology using nanoparticles would lead to increased safety, less need for regular inspection regime and more efficient materials free from fatigue issues for construction.
Nanoparticles in glass
Glass is also an important material in construction. Research is being carried out on the application of nanotechnology to glass. Titanium dioxide (TiO2) nanoparticles are used to coat glazing since it has sterilizing and anti-fouling properties. The particles catalyze powerful reactions which break down organic pollutants, volatile organic compounds and bacterial membranes. The TiO2 is hydrophilic (attraction to water) which can attract rain drops which then wash off the dirt particles. Thus the introduction of nanotechnology in the Glass industry, incorporates the self cleaning property of glass.
Risks of using nanoparticles in construction :-
In building construction nanomaterials are widely used from self-cleaning windows to flexible solar panels to wi-fi blocking paint. The self-healing concrete, materials to block ultraviolet and infrared radiation, smog-eating coatings and light-emitting walls and ceilings are the new nanomaterials in construction. Nanotechnology is a promise for making the “smart home” a reality. Nanotech-enabled sensors can monitor temperature, humidity, and airborne toxins which needs nanotech based improved batteries.