Principles, thermal separation

If your laboratory does not have access to a spectrophotometer with a thermoprogrammer, use the quick cool method described in steps 3 through 6 below to obtain a melting curve for your DNA. This method does not observe a true equilibrium between native and denatured ( melted ) DNA and is appreciably less accurate than the method described in step 1, but it will suffice to illustrate the principles underlying the thermal separation of DNA strands. 

A general problem of thermal separation teehnology is the identification of the most econontical process for the separation of mixtures into pure components or specified fractions. The separation principles are based on ... 

A. Mersm m et al.. Thermal Separation Technology Principles, Methods, Process Design, VDI-Buch, DOI 10.1007/978-3-642-12525-6 1,... 

All thermal separation processes follow this order of events. The basic principles of thermal separation processes Me now formulated and will be discussed in detail. 

The basic principles of mass transfer are discussed in detail in [1.95-1.97]. Thermal separation processes are actually mass transfer processes matter is transported between phases and across phase interfaces. Mass transfer is caused by differences in concentration within a phase and by disturbances of the phase equilibrium. The time taken to return to the phase equilibrium depends mainly on mass transfer, but also on heat transfer (heat is transported not only by convection and radiation at higher temperature, but also by mass). For the design of thermal separation processes, along with a knowledge of phase equilibria, it is also important to have a detailed understanding of how equilibrium is reached and the time required, taking into account restrictions in the mass transfer rate. 

Electrothermal atomization (ETA) for use with atomic absorption (AA) has proved to be a very sensitive technique for trace element analysis over the last three decades. However, the possibility of using the atomization/heating device for electrothermal vaporization (ETV) sample introduction into an ICP mass spectrometer was identified in the late 1980s. The ETV sampling process relies on the basic principle that a carbon furnace or metal filament can be used to thermally separate the analytes... 

Additionally, there are a number of useful electrochemical reactions for desulfurization processes (185). Solar—thermal effusional separation of hydrogen from H2S has been proposed (188). The use of microporous Vicor membranes has been proposed to effect the separation of H2 from H2S at 1000°C. These membrane systems function on the principle of upsetting equiUbrium, resulting in a twofold increase in yield over equiUbrium amounts. 

Although the continuous casting of steel appears deceptively simple in principle, many difficulties are inherent to the process. When molten steel comes into contact with a water-cooled mold, a thin soHd skin forms on the wall (Eig. 10). However, because of the physical characteristics of steel, and because thermal contraction causes the skin to separate from the mold wall shortly after solidification, the rate of heat abstraction from the casting is low enough that molten steel persists within the interior of the section for some distance below the bottom of the mold. The thickness of the skin increases because the action of the water sprays as the casting moves downward and, eventually, the whole section solidifies. 

General Principles There are two main types of mass flowmeters (1) the so-called true mass flowmeter, which responds directly to mass flow rate, and (2) the inferential mass flowmeter, which commonly measures volume flow rate aud flmd density separately. A variety of types of true mass flowmeters have been developed, including the following (a) the Maguus-effect mass flowmeter, (b) the axial-flow, transverse-momentum mass flowmeter, (c) the radial-flow, transverse-momentum mass flowmeter, (d) the gyroscopic transverse-momentum mass flowmeter, aud (e) the thermal mass flowmeter. Type b is the basis for several commercial mass flowmeters, one version of which is briefly described here. 

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