Fundamentals Of Nanoscience Set 2

Answer: heat distortion point

Explaination:
heat distortion point is the temperature at which plastics begin to become softer and defer under a load. the softening point is the temperature at which a flat-ended needle of 1 mm2 penetrates the test same at 1 mm2 depth. eutectic point the temperature at which a mixture freezes or melts. the melting point is the temperature at which the state of the body changes from solid to liquid.

Answer: bulk -> powder – > nano-particles

Explaination:
top-down approach is the one in which a material of regular size is converted into a nano-particle. in the bottom-up approach, the atoms are joined to form nano-particles.

Answer: colloidal dispersion

Explaination:
colloidal dispersion is an example of bottom up approach in the synthesis of nano particles. attrition, milling and etching are typical top down methods.

Answer: inert

Explaination:
milling is the process of particle size reduction with the objective of mixing or blending and change of particle size. an inert environment is preferred for this process.

Answer: hard and brittle

Explaination:
for the milling operation, normally hard brittle materials with fracture, deform and cold weld are used. the reason for choosing dense materials is the fact that the kinetic energy of balls depends upon their mass and velocity.

Answer: microfabrication

Explaination:
the given process is the process of microfabrication. the water is prepared and then photoresist is applied. the product is exposed to the uv light which after a series of processes, results in the fabrication of nanomaterials.

Answer: chemical vapour deposition

Explaination:
chemical vapour deposition, or cvd, is a chemical process used to produce high-purity, high-performance solid materials. the process is often used to produce carbon nanotubes.

Answer: true

Explaination:
photolithography has been the predominant patterning technique for a long time. it will require the use liquid immersion and a host of resolution enhancement technologies.

Answer: sol-gel

Explaination:
sol-gel, or chemical solution deposition, is used primarily for the fabrication of material starting from a chemical solution that acts as the precursor for an integrated network.

Answer: metal alkoxides

Explaination:
metal alkoxides and metal chlorides are basically used as precursors in sol- gel. furthermore, a colloidal suspension is formed when they undergo hydrolysis or poly- condensation.

Answer: true

Explaination:
sol-gel is a bottom-up approach in which a precursor is used to for wither a network or a colloidal suspension, so as to form desired nanoparticles.

Answer: cvc

Explaination:
cvc stands for chemical vapour condensation. it involves pyrolysis of vapours of metal organic precursors in a reduced pressure atmosphere.

Answer: helium

Explaination:
laser ablation has been extensively used for the preparation of nanoparticles. in the device, there is a pulsed flow of helium gas. it serves as a buffer gas in which clusters of the target material form, thermalize.

Answer: usm

Explaination:
usm stands for ultrasonic machining process and it is an unconventional process of machining.

Answer: all of the mentioned

Explaination:
ultrasonic machining is more versatile and can be used for the metal as well as non metal.

Answer: none of the mentioned

Explaination:
all of the mentioned are unconventional process of machining.

Answer: ultrasonic machining

Explaination:
ultrasonic machining is more versatile and can be used for the metal as well as non metal.

Answer: increase in volume of work material per impact

Explaination:
material removal rate in usm is proportional to the volume of work material per impact.

Answer: increase in number of particle making impact per cycle

Explaination:
material removal rate in usm is proportional to the number of particle making impact per cycle.

Answer: increases in frequency

Explaination:
material removal rate in ultrasonic machining is proportional to frequency.

Answer: transducer

Explaination:
transducer is a device which is used to convert one form of energy to other.

Answer: feeding unit

Explaination:
feeding unit is used to apply working force during a machining operation.

Answer: increase in amplitude

Explaination:
material removal rate in ultrasonic machining is proportional to amplitude.

Answer: 10-20 nm

Explaination:
since colloidal are intermediate between powdered particles and suspension particles, they have a size in between these particles of about 10 to 20 nm. these are considered to be intermediate size of molecules.

Answer: it forms turbid layers

Explaination:
since a colloidal particle does not from a single layer with solvents, the only possibility is to form a turbid layer where the solution is an intermediate between a miscible and immiscible solution.