Applications of Nanotechnology

Nanotechnology has found wide-ranging applications in many fields. There are following some of the important applications discussed below.

1) Electronics: Nanosized electronic components show unique properties which are different from the larger semiconductor components. The semiconductor devices are based on the concept of charge transport only whereas the nanosized components work on the concept of charge as well as spin transport of electrons. This has been used in devices like spin FET, Spin LED etc. These devices have increased the data storage capacities of hard disks and have led to small and faster microprocessors.

2) Energy: Attempts are being made to increase the efficiency of solar cells by using nanotechnology. Another important area of research is the use of hydrogen as a fuel. The main problem with hydrogen is that it is highly combustible and hence cannot be stored easily. Efforts are being made to use carbon nanotubes to trap and store hydrogen. Nanoparticles are also being used to increase the energy density of rechargeable batteries which are used in laptops and mobile phones.

3) Automobiles: Nanotube composites have better mechanical strength compared to steel but are costly at present. Efforts are being made to develop cheaper nanotube composites that can replace steel which is used to construct the body structure of automobiles. The use of nanoparticles in paints provides thin and smooth coatings. Nanoparticles are being used to develop lightweight and less rubber-consuming tyres for automobiles which will increase the mileage of the automobiles. The use of carbon nanotubes for storing hydrogen is being explored so that automobiles can be run on hydrogen as a fuel. Nanomaterial catalysts can be used as catalysts to convert the harmful emissions from automobiles to less harmful gases.

4) Space and defence: Aerogels are porous materials with nanosized pores. They have very low density and are poor conductors of heat. They can be used in spacecraft, lightweight suits and jackets. Polymer composites using silica fibres and nanoparticles have larger mechanical strength and low-temperature coefficient of expansion. They can be used in spacecrafts which have to withstand high temperature and stress conditions during launching and re-entry into the earth's atmosphere. Satellites and spacecrafts use solar energy. The efficiency of solar cells can be increased using nanoparticles. The use of nanoparticles will also make the solar cells smaller in size and lightweight.

5) Medical: Nanoparticles can be used for the detection and treatment of cancers and tumours. The nanoparticles are injected into the body and guided towards a specific part. Drugs can be encapsulated in nanocapsules and guided towards any specific part where the drug can be delivered in a controlled manner by opening the capsule at a desired rate using magnetic fields or infrared light. This targeted drug delivery does not affect healthy organs. Nanotechnology-based tests are being developed for fast detection of viruses and antibodies.

6) Environmental: Nanoparticle-based sensors are capable of detecting water and air pollution due to toxic ions and pesticides with a very high sensitivity. Nanomaterial catalysts can be used as catalysts to convert the harmful emissions from industries and automobiles to less harmful gases. Nanotubes can be used to store hydrogen fuel which, when used in automobiles, will reduce harmful emissions.

7) Textiles: The use of nanotechnology in the textile industry has led to the development of water-repellent and wrinkle-free clothes.

8) Cosmetics: Zinc oxide and titanium oxide nanoparticles are used in sunscreen lotions which protect the skin from ultraviolet radiation. These nanoparticles absorb ultraviolet radiation. Nanoparticle-based dyes and colours are harmless to the skin and hence are used in hair creams, gels and hair dyes.

Numerical Aperture and Acceptance Angle of the Optical Fibre

Angle of Acceptance → If incident angle of light on the core for which the incident angle on the core-cladding interface equals the critical angle then incident angle of light on the core is called the "Angle of Acceptance. Transmission of light when the incident angle is equal to the acceptance angle If the incident angle is greater than the acceptance angle i.e. $\theta_{i}>\theta_{0}$ then the angle of incidence on the core-cladding interface will be less than the critical angle due to which part of the incident light is transmitted into cladding as shown in the figure below Transmission of light when the incident angle is greater than the acceptance angle If the incident angle is less than the acceptance angle i.e. $\theta_{i}<\theta_{0}$ then the angle of incidence on the core-cladding interface will be greater than the critical angle for which total internal reflection takes place inside the core. As shown in the figure below Transmission of lig

click here »

Fraunhofer diffraction due to a single slit

Let $S$ be a point monochromatic source of light of wavelength $\lambda$ placed at the focus of collimating lens $L_{1}$. The light beam is incident normally from $S$ on a narrow slit $AB$ of width $e$ and is diffracted from it. The diffracted beam is focused at the screen $XY$ by another converging lens $L_{2}$. The diffraction pattern having a central bright band followed by an alternative dark and bright band of decreasing intensity on both sides is obtained. Analytical Explanation: The light from the source $S$ is incident as a plane wavefront on the slit $AB$. According to Huygens's wave theory, every point in $AB$ sends out secondary waves in all directions. The undeviated ray from $AB$ is focused at $C$ on the screen by the lens $L_{2}$ while the rays diffracted through an angle $\theta$ are focussed at point $p$ on the screen. The rays from the ends $A$ and $B$ reach $C$ in the same phase and hence the intensity is maximum. Fraunhofer diffraction due to

click here »

Particle in one dimensional box (Infinite Potential Well)

Let us consider a particle of mass $m$ that is confined to one-dimensional region $0 \leq x \leq L$ or the particle is restricted to move along the $x$-axis between $x=0$ and $x=L$. Let the particle can move freely in either direction, between $x=0$ and $x=L$. The endpoints of the region behave as ideally reflecting barriers so that the particle can not leave the region. A potential energy function $V(x)$ for this situation is shown in the figure below. Particle in One-Dimensional Box(Infinite Potential Well) The potential energy inside the one -dimensional box can be represented as $\begin{Bmatrix} V(x)=0 &for \: 0\leq x \leq L \\ V(x)=\infty & for \: 0> x > L \\ \end{Bmatrix}$ $\frac{d^{2} \psi(x)}{d x^{2}}+\frac{2m}{\hbar^{2}}(E-V)\psi(x)=0 \qquad(1)$ If the particle is free in a one-dimensional box, Schrodinger's wave equation can be written as: $\frac{d^{2} \psi(x)}{d x^{2}}+\frac{2mE}{\hbar^{2}}\psi(x)=0$ $\frac{d^{2} \psi(x)}{d x

click here »

Physics Vidyapith ✍️

Search This Blog