Power generation from low-temperature heat sources (80–300 °C) like thermal solar, geothermal, biomass or waste heat has been becoming more and more significant in the last few decades. Organic ...Rankine Cycle (ORC) uses organic working fluids, obtaining higher thermal efficiency than with water used in traditional Rankine Cycles, because of the physical (thermodynamic) properties of these fluids. The traditional classification of pure (one-component) working fluids is based on the quality of the expanded vapour after an isentropic (adiabatic and reversible) expansion from saturated vapour state, and distinguishes merely three categories: wet, dry and isentropic working fluids. The purpose of this paper is to show the deficiencies of this traditional classification and to introduce novel categorisation mostly to help in finding the thermodynamically optimal working fluid for a given heat source.
•The need for a refined working fluid classification (beyond the classical categories wet/isentropic/dry) is demonstrated.•A novel classification based on characteristic points is introduced.•Potential technical applications for the new classification are presented.•Categories and characteristic points for 57 pure working fluids are provided.
Samples of whole blood were obtained from 51 patients with newly diagnosed colorectal cancer as well as from 76 patients with neoplastic colorectal polyp, and from 30 healthy blood bank donors. ...Selenium was determined by the fluorimetric method. Significantly decreased selenium concentrations of blood samples from patients with colorectal cancer and villous adenoma were found. There was not any correlation between the blood selenium levels of patients with adenomatous polyp and the severity of dysplasia in removed polyps. The lowest mean selenium level in patients with villous adenoma indicates that selenium deficiency may be an important factor in the development of colorectal cancer arising from villous adenomas.
