Mechanics
Holmarc's Young's modulus apparatus (Model No: HO-ED-M-02) is used to measure the Young's modulus of a bar. Young's modulus is a measure of stiffness of an elastic material and is a quantity used to characterize materials. It can vary considerably depending on the exact composition of the material. If the beam is loaded at its mid-point, the depression produced will not form an arc of a circle. This type of bending is called non-uniform bending. If the beam is loaded at both ends, the elevation produced will form an arc of a circle. This type of bending is called uniform bending. Two methods are used to measure Young's modulus of the bar in both uniform and non-uniform bending. They are Pin and Microscope method and Optic lever method.
Lee's Disc Apparatus comprises of a brass disc resting on another slab of the same dimension with special heating coil. Both metallic discs have radial holes for the sensitive thermistors. Material under test is placed in between two discs. The heater is turned on and the apparatus is left idle until the temperature gets stabilized. At this point the heat energy passing through the heat sample will be exactly equal to the heat flowing out of the lower block.
Maximum temperature the disc can achieve during the experiment is around 60 degree Celsius to make it safe for handling with even bare hands. Similarly, operating voltage for heating coil sandwiched between the discs is fixed as 50V for safety. The temperature sensors used are highly sensitive and accurate with least count as low as 0.2 degree Celsius. Front panel is equipped with digital display and keyboard for user friendly operation.
This Apparatus provides the facility for performing experiments using different kinds of sample materials. The front panel includes LCD display and keyboard for readouts and settings.
There are three operation modes for this Equipment - Manual mode, Auto mode and PC mode. In manual mode, the user can calculate thermal conductivity using the acquired data manually. In auto mode, the user can retrieve result directly from the system once the temperature stabilized. In PC mode, one can monitor progress of the experiment through a computer and can calculate thermal conductivity with the help of Holmarc’s software. This diversity of usage makes the equipment user friendly.
Caution : Do NOT touch the discs with bare hands during the time of heating. High temperature can make severe burns in the body. Try to use gloves for handling the discs.
Experiment
To determine thermal conductivity of bad conductors (Glass, Nylon, Plywood, etc.) in the form of a disc using Lee's method.
Thermal conductivity,
k = (Mc dT / dt ) / (πr2 (T2 - T3) ) × (r + 2h) d / 2( r + h) W / mK-1
Where,
M = Mass of the metallic disc
c = Specific heat capacity of the metallic disc
h = Height of the metallic disc
r = Radius of the metallic disc
dT / dt = Rate of cooling of the metallic disc at T2
d = Thickness of the sample
T2 - T3 = Steady temperatures recorded at T2 and T3 respectively
Scope of Supply
Model No: ED-M-03-LDCU
Input : 230V 5Amp AC
Quantity : 1 no.
Model No: ED-M-03-HUD
Operating Voltage (Manual Model) : 50 V
Quantity : 1 no.
Model No: ED-M-03-BD
Material : Cartridge Brass
Diameter : 76.2 mm
Height : (Block, B1) & 8 mm (Block B4)
Quantity : 1 no. each
Model No: ED-M-03-APC
Type : 3 core 3 Pin
Least Count : 1 mm
Quantity : 1 no.
Model No: ED-M-03-TS
Material : Borofloat glass, Teflon, Nylon
Quantity : 1 no. each
RS 232 PC cable and connector
Heat Sink Compound
software CD
Instruction Manual
Established in 1993, Holmarc Opto-Mechatronics Ltd manufactures variety of scientific and engineering instruments for research, industry and education.
ISO 9001:2015 Made in INDIA
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B.7., H.M.T. Industrial Estate
H.M.T. P.O, Kalamassery, Kochi
Kerala, India - 683 503
+91 920-719-7772 / 6 / 1
sales@holmarc.com
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