Membrane Processing

• Atomizer Types in Spray Drying:
• Two-Fluid (Pneumatic) Atomizers: Utilize high-velocity compressed air or steam to contact and shear a low-rate liquid stream into an extremely fine spray mist.
• They produce very small, uniform droplets (droplet diameters $\le 15-20\,\mu\text{m}$) and operate effectively at very small liquid flow rates, making them standard for pilot-scale, laboratory spray dryers, and specialized encapsulation feeds.
• Centrifugal (Rotary Disk) Atomizers: Handle large commercial capacities, producing droplets between $30-120\,\mu\text{m}$.
• Pressure Nozzles: Require high pressures ($10-30\text{ MPa}$) and produce larger droplet distributions.
• Correct Option: Option 3 (Two fluid atomizers).

• Arrangement of Physical Constants by Increasing Magnitude:
• Evaluating the numerical magnitude of each physical constant in standard SI units:
• Planck's Constant ($h$): $h \approx 6.626 \times 10^{-34}\ \text{J}\cdot\text{s}$ (Order of magnitude: $10^{-34}$)
• Stefan-Boltzmann Constant ($\sigma$): $\sigma \approx 5.670 \times 10^{-8}\ \text{W}\cdot\text{m}^{-2}\cdot\text{K}^{-4}$ (or $\text{kg}\cdot\text{s}^{-3}\cdot\text{K}^{-4}$, Order of magnitude: $10^{-8}$)
• Universal Gas Constant ($R$): $R \approx 8.314\ \text{J}\cdot\text{mol}^{-1}\cdot\text{K}^{-1}$ (Order of magnitude: $10^{0} \approx 8.31$)
• Speed of Light in Vacuum ($c$): $c \approx 2.998 \times 10^{8}\ \text{m/s}$ (Order of magnitude: $10^{8}$)
• Ranking by Numerical Value:

$$6.626 \times 10^{-34} \lt 5.670 \times 10^{-8} \lt 8.314 \lt 2.998 \times 10^{8}$$ $$\text{B} \lt \text{A} \lt \text{D} \lt \text{C}$$

• Conclusion: The increasing order of magnitude is B, A, D, C (Option 1).

Correct option: (1) B,A,D,C

• Far-Infrared (FIR) Heating Mechanisms:
• Far-Infrared (FIR) radiation spans wavelengths from $3\,\mu\text{m}$ to $1000\,\mu\text{m}$.
• The fundamental vibrational frequencies of chemical bonds (stretching and bending of $O-H$ in water, $C-H$, and $C=O$ bonds in organic biomolecules) fall precisely within the infrared spectral region ($2.5-15\,\mu\text{m}$).
• Absorption of FIR photons excites molecular vibrations (stretching, bending, rocking), which rapidly dissipates into kinetic thermal energy, heating the food product efficiently.
• Molecular rotation is excited primarily by microwave radiation.
• Correct Option: Option 2 (Molecular vibration).

Evaluating the Assertion and Reason concerning High pressure processing:

The correct answer is Option 2: Both (A) and (R) are true but (R) is NOT the correct explanation of (A).