poster - International Conference of Agricultural Engineering

The density analysis was performed with the aid of a 25 mL beaker where the sample was
weighed and measured, then subjected to the desired temperature, -15, -10, -5, and 0 o C in
vertical freezer, 20, 40 and 60 o C in B.O.D, 80 o C in an oven, monitored by a thermocouple,
after get the temperature, the sample was weighed again and it was checked to made a
relationship between the mass and volume (Equation 1) to obtain the density.
m
ρ =
v
(1)
where:
ρ = Density (g/cm 3 );
m = mass (g);
v = volume (cm 3 )
Determination of the point of minimum flow was second 1149 NBR- Oil Product - The
point of minimum flow is the lowest temperature at which the lubricating oil is still flowing. In
the test, it cooled the oil sample within a tube and each decrease of 3 °C in temperature, it
was observed whether or not the movement of the surface of the oil inside the tube and, after
5 seconds is lacking movement that temperature, it will have reached the freezing point and
a temperature of 3 °C above this temperature will be at the point of minimum flow.
It was used to determine the viscosity, the B3 Hoppler viscosimeter. The viscosity of
castor oil was determined in a temperature range of -15, -10, -5, 0, 20, 40, 60 and 80 0 C with
the aid of a thermostated bath for obtaining the same. This is done through the time interval
(Δt) that particular sphere of specific mass (ρ), constant (K) and diameter (D) known travels a
distance (ΔL). The calculation is done by Equation 2:
µ = K (δ 2 - δ 1 ) ∆t (2)
which:
μ = viscosity, mPas -1
K = constant of the sphere, mPacm -3
δ 2 = specific mass of the sphere, gcm -3
δ 1 = density of sample, gcm -3
∆t = fall time, s.
The specific heat was determined using a handmade colorimeter constructed in a
thermical bottle with a layer of glass fiber placed inside of a PVC tube, where a digital
thermometer measures the temperature inside the calorimeter.
To determine the heat capacity of the calorimeter are placed 100 g of water at
environmental temperature (25 °C) within the calorimeter; this, in turn, it is sealed with a
rubber coupled to a thermometer indicating a temperature T 1 within the calorimeter and then
are placed in the container in 100 g of water at an average temperature of approximately 3
°C, corresponding to the temperature T 2 ; stir the calorimeter at the time of 10 min until they
reach the equilibrium temperature T 3 . The heat capacity was determined by Equation 3:
C 1 m 1 (T 1 -T 3 ) + Ccal (T 1 -T 3 ) = C 2 m 2 (T 3 -T 2 ) (3)