Some thermal engineering aspects of protecting the condensate-feedwater path of a cogeneration station against corrosion

Questions pertinent to making the thermal deaeration of feedwater flows more energy efficient, the advisability of using chemical methods for final deoxygenation of feedwater, and checking the tightness of vacuum systems used in turbine units are considered.     

Improvement of water thermal deaeration technologies

The results of industrial test investigations of an advanced spray-jet deaerator are discussed. The capability of attaining the specified quality of water at a flash-steam flowrate of 0.07 kg/t (that is, at an essential approximation to the theoretical specific flowrate) and the minimum residual oxygen content in the deaerated water is proved to be possible.     

Hydration Shells of DNA from the Point of View of Terahertz Time-Domain Spectroscopy

Hydration plays a fundamental role in DNA structure and functioning. However, the hydration shell has been studied only up to the scale of 10–20 water molecules per nucleotide. In the current work, hydration shells of DNA were studied in a solution by terahertz time-domain spectroscopy. The THz spectra of three DNA solutions (in water, 40 mm MgCl₂ and 150 mM KCl) were transformed using an effective medium model to obtain dielectric permittivities of the water phase of solutions. Then, the parameters of two relaxation bands related to bound and free water molecules, as well as to intermolecular oscillations, were calculated. The hydration shells of DNA differ from undisturbed water by the presence of strongly bound water molecules, a higher number of free molecules and an increased number of hydrogen bonds. The presence of 40 mM MgCl₂ in the solution almost does not alter the hydration shell parameters. At the same time, 150 mM KCl significantly attenuates all the found effects of hydration. Different effects of salts on hydration cannot be explained by the difference in ionic strength of solutions, they should be attributed to the specific action of Mg²⁺ and K⁺ ions. The obtained results significantly expand the existing knowledge about DNA hydration and demonstrate a high potential for using the THz time-domain spectroscopy method.