## Determination of radiation constant of brass, iron, unpainted and painted glass

Pharmaceutical Engineering Practical Lab Manual PDF Download

### AIM:

To determine the radiation constant of unpainted glass.

### PRINCIPLE:

The flow of heat takes place from the high-temperature region toward the low-temperature region. This is based upon the following three mechanisms.

A) CONDUCTION

It is considered one of the efficient modes of heat transfer this mechanism of heat transfer occurs through this mechanism by heat transfer occurs through transfer of the momentum of each atom or molecule without mixing conduction is limited to solids and fluid.

B) CONVECTION:

In this mode of heat transfer, the warmer parts mix with the colour parts of the same substance heating water by using a coil type of water heater is one of the examples of convections here, the energy is transferred as heat to a flowing fluid by hot surface convection is limited to the flow of heat in fluids(i.e, liquids and gases).

C) RADIATION:

The mechanism of heat transfer through apace by means of electromagnetic waves is called radiation. A good example of radiation is black body radiation which occurs by absorbing all energy incidents upon it, at the same time the quantitatively transferred into heat the radiant thermal energy expressed by “STEFFAN BALOZMANN” equation as given below.

q =bAT4

Where,

q = energy radiated per second (w) A= Area of radiating surface (m2)

T= absolute temperature of the radiating surface (k) b= constant w/m2 x k4

The radiation constant is calculated by using the following equation,

M1 S1 – M2 S2 dq/dt = α A [(T1/100)4-(T2-100)4]+b A (T1-T2)

### REQUIREMENTS:

- Round bottom flask (unpainted)
- Thermometer (1100)
- Hot plate or burner
- Stain with clamp
- Stop clock, Tripod stand
- Weighing balance
- Purified water

### PROCEDURE:

- A round bottom flask is cleaned and dried.
- The weight of the flask is determined(M2/kg)
- The diameter(d) of the neck of the flask is determined
- Boil hot water is prepared and the measured volume of hot water is transferred to the flask (M1). The volume of water is the external surface of the round bottom flask is thoroughly dried the flask with hot water is placed on the tripod stand.
- The thermometer (1100) is dipped in the centre of the flask and tied at the top to an iron
- stand.
- Slowly the temperature of the hot body decreases.
- The decrease in temperature is noted every minute.
- The data are recorded in a table.

- A graph is plotted by taking time (minutes) or X-axis and temperature on Y-axis normally is a curve is obtained.
- Depending on the temperature at which the radiation constant is determined, a tangent is drawn at that temperature the slope is calculated (dq/dt).
- The radiation constant (α) is determined at the temperature.

### Calculations:

Diameter of round bottom flask (d) = Radius of round bottom flask (r) =

Diameter of neck of round bottom flask (d) = Radius of neck of round bottom flask (r) = Surface area of round bottom flask = 4Пr2 – Пr2 Empty weight of round bottom flask (M2) = Volume of heat water with flask (M1) =

Room temperature (t2) = Derived room temperature (t1) = Specific heat of water (r1) = Specific heat of glass (r2) =

M1 S1 – M2 S2 dq /dt = α A [(T1/100)4-(T2-100)4]+b A (T1-T2)

### REPORT:

The radiation constant of unpainted glass α =

**Pharm Engg Chapterwise MCQ:** **UNIT-I** **MCQ *** Flow of fluids * Size reduction * Size separation **UNIT-I**I **MCQ ***Heat transfer *Distillation *Evaporation **UNIT-III** **MCQ ***Drying * Mixing **UNIT-IV** **MCQ *** Filtration * Centrifugation * **UNIT-V** **MCQ **Materials of construction * Corrosion

Pharmaceutical Engineering Practical Lab Manual PDF Download

I. Determination of radiation constant of brass, iron, unpainted and painted glass.

II. Steam distillation – To calculate the efficiency of steam distillation.

III. To determine the overall heat transfer coefficient by the heat exchanger.

IV. Construction of drying curves (for calcium carbonate and starch).

V. Determination of moisture content and loss on drying.

VI. Determination of humidity of the air – i) From wet and dry bulb temperatures –use of Dew point method.

VII. Description of Construction working and application of Pharmaceutical Machinery such as rotary tablet machine, fluidized bed coater, fluid energy mill, dehumidifier.

VIII. Size analysis by sieving – To evaluate size distribution of tablet granulations – Construction of various size frequency curves including arithmetic and logarithmic probability plots.

IX. Size reduction: To verify the laws of size reduction using a ball mill and determining Kicks, Rittinger’s, Bond’s coefficients, power requirement and critical speed of Ball Mill.

X. Demonstration of colloid mill, planetary mixer, fluidized bed dryer, freeze dryer and such other major equipment.

XI. Factors affecting Rate of Filtration and Evaporation (Surface area, Concentration and Thickness/ viscosity)

XII. To study the effect of time on the Rate of Crystallization.

XIII. To calculate the uniformity Index for a given sample by using Double Cone Blender.