Evangelos I. Gkanas

Modeling and Simulation for Absorption- Desorption Cyclic Process on a Three-Stage Metal Hydride Hydrogen Compressor

Abstract In the current work a mathematical and a simulation study on a three – stage metal hydride hydrogen compressor (MHHC) is presented. Multistage MHHC uses a combination of different materials acting as metal hydrides in order to increase the final compression ratio, while maximizing the absorption capacity of every single stage supply pressure. The performance of a MHHC can be predicted by solving simultaneously the heat, mass and momentum differential equations. The materials used for the current study are LaNi 5 , MmNi 4.6 Al 0.4 and Ti 0.99 Zr 0.01 V 0.43 Fe 0.99 Cr 0.05 Mn 1.5 . This three – stage compression system yields a pressure ratio of 25:1, for supply conditions 20 ° C and 5 bar. The delivery pressure achieved is 115 bar for 100 ° C desorption temperature.

Chemical characterization of particulate matter (PM) and source apportionment study during winter and summer period for the city of Kozani, Greece

Eordaia basin located in northwest of Greece, comprises an area which is characterized by intense energy related activities, including coal burning at four power plants and the associated mining operations. Air samples of inhalable (PM10) and respirable particles (PM2.5) were collected in cold and warm periods in 2010 at an urban background site of Kozani, the major city and capital of the region which is located close to the power plants. Particulate matter concentration, particle-bound polycyclic aromatic hydrocarbons and anionic species concentrations were determined using gravimetric, GC-MS in SIM mode and Ion Chromatography analysis, respectively. For the cold period, the mean PM10 and PM2.5 mass concentration was found to be 19.62 and 14.68 µg m−3, respectively. Correspondingly, for the warm period, the mean PM10 and PM2.5 values were 35.29 and 25.75 µg m−3, respectively. In general, the results indicated that the major sources of air pollution in Kozani are traffic, combustion from agricultural activities and lignite power plants emissions, contributing by different percentages to each particle fraction.

In vitro magnetic hyperthermia response of iron oxide MNP’s incorporated in DA3, MCF-7 and HeLa cancer cell lines

AbstractIn the current work, iron oxide magnetic nanoparticles (MNP’s) were synthesized by thermal decomposition of Fe(acac)3-(iron acetylacetonate) compounds in high-boiling organic solvents containing stabilizing surfactants and examined as possible agents for magnetic hyperthermia treatment, according to their structural, magnetic and heating properties. Three different cancer cell lines (DA3, MCF-7 and HeLa cell lines) were used to assess the suitability of the MNP’s. The experimental results proved that the synthesized MNPs are non-toxic and the uptake efficiency was extremely good. Further, from in vitro hyperthermia results, very fast thermal response was observed (reaching hyperthermia levels in less than 200 s), which minimize the duration of the cell and human body exposure in a high frequency AC external magnetic field.

Microstuctural analysis and determination of PM10 emission sources in an industrial Mediterranean city

AbstractScientists are interested in knowing more about the control of sources which contribute to environmental pollution. Air pollution has two main sources: anthropogenic and natural sources. The natural contributions to environmental pollution can be assessed, but cannot be totally controlled. while the emissions from the anthropogenic sources can be controlled. These air pollutants can be dispersed and transferred by winds in the atmosphere. The focus area of this study is the Mediterranean basin. The most important winds in this area are the land and sea breezes. Scanning Electron Microscopy (SEM) was applied to characterize the morphology of the PM10 samples in order to identify possible emission sources for the occuring pollution. Energy Dispersive X-ray Spectroscopy (EDS) was performed for the elemental analysis and chemical characterization of the PM10 samples. The analysis showed that the PM10 samples can be divided into three different groups: the samples containing mineral phases, the compounds from combustion processes and the particles emitted from high-temperature processes.