1.
APPLICATION OF
IRREVERSIBLE PROCESS TO
BIOLOGICAL SYSTEM
PRESENTED TO PRESENTED BY
Dr. Reena singh Akash kumar singh
M.Sc.(III sem)
DAC BBAU LUCKNOW
ASSIONMENT
2.
From the greek therme (heat) and dynamis (power,force)
- The capacity of hot bodies to produce work
The power of heat
Sadi Carnot
(1796-1832)
Réflexions sur la puissance motrice du feu et
sur les machines propres à développer cette puissance
3.
Reversible (ideal)
system and surroundings can be restored to the initial state
from the final state without producing any changes in the
thermodynamics properties
it should occur infinitely slowly due to infinitesimal gradient
all the changes in state occurred in the system are in
thermodynamic equilibrium with each other
Irreversible (natural)
All processes in nature are irreversible
Finite gradient between the two states of the system
heat flow between two bodies occurs due to temperature gradient
between the two bodies;
Reversible and Irreversible
Processes
4.
• Some factors that cause a reversible process to become
irreversible:
• Friction
• Unrestrained expansion and compression
• Mixing
• Heat transfer (finite ΔT)
• Inelastic deformation
• Chemical reactions
5.
In a reversible process things happen very slowly,
without any resisting force, without any space limitation
→ everything happens in a highly organized way (it is
not physically possible ‐ it is an idealization).
6.
Examples: Some examples of nearly reversible processes
are:
(i) Frictionless relative motion.
(ii) Expansion and compression of spring.
(iii) Frictionless adiabatic expansion or compression of
fluid.
(iv) Polytropic expansion or compression of fluid.
(v) Isothermal expansion or compression.
(vi) Electrolysis.
7.
An irreversible process is one in which heat is
transferred through a finite temperature. In
summary, processes that are not reversible are
called irreversible.
Examples of irreversible process.
(i) Relative motion with friction
(ii) Combustion
(iii) Diffusion
(iv) Free expansion
(v) Throttling
(vi) Electricity flow through a resistance
(vii) Heat transfer
(viii) Plastic deformation.
8.
Laws of
thermodynamics
0th
Definition of temperature
Systems at different temperatures exchange energy until
reaching a thermal equilibrium
1st
Conservation of energy
heat is a form of energy
2nd
Entropy of an isolated system never decreases
perpetual motions of machines is impossible
3rd
Entropy at absolute zero temperature (0 K)
it is impossible to cool a system until zero
9.
App. Of irreversible Therm. To biological system
OR
Biological importance for irreversible system
Biological system are open system which exchange
both matter and energy with the environment
The growth of a living organism or cell is
characterized by transition resulting in greater order
and thus decrease of entropy from the initial state
If we treat a biological system as an isolated system
,rather than as an open system , then it appears to
violate the basic principal of thermodynamic.
10.
The theory of stationary non-equilibrium states leads to
a better understanding of the global behavior of living
organism
Regardless of the nature of the constant parameters , the
stationary state may be regarded as the state of min.
entropy production per time
In a biological system , the main contribution to entropy
production , diS/dt , is positive arises from the process
of metabolism whereby the assimilated food is degraded
into simple substances such as CO2 , accompanied by an
energy release .
11.
As the organism grows , though diS/dt is positive ,
deS/dt is negative and greater than diS/dt.
