Question 34 (Textile Engineering & Fibre Science)
Which of the following combination of statements from options A, B, C, and D is correct ?
1. X-ray Diffraction gives information about crystallinity and crystal size in semicrystalline polymers.
2. Differential Scanning Calorimetery gives information about Tg, Tm and Tc as well as enthalpy of melting and crystallization.
3. In Scanning Election Microscopy the sample has to be coated with silver to make it conducting.
4. Birefringence is measure of molecular orientation in amorphous phase only
| (A) | 1, 2 and 3 are correct |
| (B) | 1, 3 and 4 are correct |
| (C) | 2, 3 and 4 are correct |
| (D) | All are correct |
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Frequently Asked Questions | FAQs
What are the applications of X-ray diffraction(XRD)?
X-ray diffraction (XRD) has a wide range of applications in materials science, chemistry, physics, geology, and biology. Some of the most common applications of XRD include:
Material identification: XRD can be used to identify the crystalline structure of materials, including minerals, metals, ceramics, and polymers. This information can be used to determine the composition, purity, and quality of a material.
Crystal structure determination: XRD is a powerful tool for determining the atomic and molecular structure of crystals. This information can be used to understand the physical and chemical properties of materials, as well as to design new materials with specific properties.
Phase analysis: XRD can be used to analyze the different phases of a material, including their relative proportions and crystal structures. This information can be used to understand the behavior of materials under different conditions, such as changes in temperature or pressure.
Texture analysis: XRD can be used to analyze the texture and preferred orientation of crystalline materials. This information can be used to optimize manufacturing processes and to design materials with specific properties.
Thin film analysis: XRD can be used to analyze the crystal structure of thin films and coatings, which are used in a wide range of applications, including electronics, optics, and solar cells.
Protein crystallography: XRD is a key tool in protein crystallography, which is used to determine the three-dimensional structure of proteins. This information is essential for understanding protein function and for designing drugs that target specific proteins.
Overall, XRD is a versatile and powerful tool for studying the structure and properties of materials across a wide range of fields and applications.
What is differential scanning calorimeter used for?
A differential scanning calorimeter (DSC) is a type of thermal analysis instrument that is used to measure the thermal behavior of materials as a function of temperature or time. DSC measures the heat flow into or out of a sample as it is subjected to a controlled temperature program, and can provide information about a range of material properties.
Some common applications of DSC include:
Melting and crystallization behavior: DSC can be used to study the melting and crystallization behavior of materials, including polymers, metals, and ceramics. By measuring the heat flow during a controlled heating or cooling cycle, DSC can provide information about the melting point, crystallization temperature, and degree of crystallinity of a material.
Glass transition temperature: DSC is often used to measure the glass transition temperature (Tg) of polymers and other materials. Tg is the temperature at which a material transitions from a rigid, glassy state to a more flexible, rubbery state. This information is important for understanding the mechanical and physical properties of a material.
Reaction kinetics: DSC can be used to study the kinetics of chemical reactions, such as curing, cross-linking, and oxidation. By monitoring the heat flow during a reaction, DSC can provide information about the reaction rate, activation energy, and other kinetic parameters.
Stability and shelf life: DSC can be used to study the stability and shelf life of materials, such as pharmaceuticals, food products, and cosmetics. By subjecting a sample to a controlled temperature and humidity program, DSC can provide information about the stability of a material over time.
Overall, DSC is a powerful tool for studying the thermal behavior of materials and can provide valuable information about their physical and chemical properties.
What is scanning electron microscopy used for?
Scanning electron microscopy (SEM) is a powerful imaging technique that uses a focused beam of electrons to scan the surface of a sample and produce high-resolution images. SEM is used in a wide range of fields and applications, including materials science, nanotechnology, biology, and geology.
Some common applications of SEM include:
Surface morphology: SEM can be used to study the surface morphology and topography of materials at high magnification. This information can be used to understand the microstructure of materials and to identify surface features such as cracks, pores, and defects.
Elemental analysis: SEM can be used to analyze the elemental composition of a sample using energy-dispersive X-ray spectroscopy (EDS). By measuring the characteristic X-rays emitted by the sample when it is bombarded with electrons, EDS can provide information about the elemental composition and distribution of a sample.
Chemical imaging: SEM can be used to produce chemical images of a sample using electron energy loss spectroscopy (EELS) or X-ray photoelectron spectroscopy (XPS). These techniques can provide information about the chemical composition and distribution of a sample.
Nanoparticle characterization: SEM is often used to study the morphology and size distribution of nanoparticles, which are used in a wide range of applications, including electronics, medicine, and environmental remediation.
Biological imaging: SEM can be used to image biological samples, including cells, tissues, and organs. This information can be used to study the structure and function of biological systems at the cellular and molecular level.
Overall, SEM is a versatile and powerful imaging technique that is used in a wide range of fields and applications to study the structure, composition, and properties of materials and biological systems.
What do you mean by birefringence?
Birefringence, also known as double refraction, is a property of anisotropic materials that causes a beam of light to split into two perpendicular polarization components with different refractive indices when it passes through the material. This effect is due to the anisotropic nature of the material, which means that its optical properties vary with direction.
The difference in refractive index between the two polarization components is called the birefringence of the material. Birefringence can be quantified by measuring the difference between the ordinary index of refraction (n_o) and the extraordinary index of refraction (n_e).
Birefringence is commonly observed in materials such as calcite, quartz, and many liquid crystals. It can be used to create polarizing filters, which are used in many optical applications, including LCD displays, photography, and microscopy.
In addition, birefringence can provide valuable information about the structure and properties of materials. For example, by measuring the birefringence of a material under stress, it is possible to determine the stress distribution within the material. Birefringence can also be used to study the molecular orientation and alignment in polymers and other anisotropic materials.