Size-exclusion chromatography (SEC) separates polymer molecules and biomolecules based on differences in their molecular size. The separation process in simpliﬁed form is based on the ability of sample molecules to penetrate inside the pores of packing material and is dependent on the relative size of analyte molecules and the respective pore size of the absorbent. The process also relies on the absence of any interactions with the packing material surface. Two types of SEC are usually distinguished: 1.
The closed engine test cell system makes a suitable case for students to study an example of the flow of heat and change in entropy. In almost all engine test cells the vast majority of the energy comes into the system as highly concentrated ‘chemical energy’ entering the cell via the smallest penetration in the cell wall, the fuel line. It leaves the cell as lower grade heat energy via the largest penetrations: the ventilation duct, engine exhaust pipe and the cooling water pipes.
When analyzing kinetic data or designing a chemical reactor, it is important
to state clearly the definitions of reaction rate, conversion, yield, and selectivity.
For a homogeneous reaction, the reaction rate is defined either as the
amount of product formed or the amount of reactant consumed per unit
volume of the gas or liquid phase per unit time. We generally use moles
(g mol, kg mol, or lb mol) rather than mass to define the rate, since
this simplifies the material balance calculations.
Given that the pool of underutilized labour is large in almost
all developing countries (either in the form of open unemployment or in the form of hidden
unemployment in both the agricultural and the informal sector), this then leads to an increase
in employment in the modern sector which in turn leads to more incomes and savings. The
expansion of the production of the modern sector moreover brings about the penetration of
modern technology into the economy and hence an increase in productivity and goods supply,
also adding to higher incomes.
Since its inception in 1997, DOE’s Carbon Sequestration
Program – managed within FE and implemented by
NETL – has been developing both core and supporting
technologies through which CCS can become an
effective and economically viable option for reducing
CO2 emissions from coal-based power plants (NETL,