Effect of sample thickness on carbon ejection from ultrathin graphite bombarded by keV C_{60}

Molecular dynamics computer simulations are employed to investigate the effect of a sample thickness on the ejection process from ultrathin graphite. The thickness of graphite varies from 2 to 16 graphene layers and the system is bombarded by 10 keV C₆₀ projectiles at normal incidence. The ejection yield and the kinetic energy of emitted atoms are monitored. The implications of the results to a novel analytical approach in secondary ion mass spectrometry based on the ultrathin free-standing graphene substrates and transmission geometry are discussed

A probabilistic approach to assessment of the quality of drinking water

Knowledge of uncertainty in analytical results is of prime importance in assessments of compliance with requirements set out for the quality of water intended for human consumption. Assessments of drinking water quality can be performed using either a deterministic or a probabilistic method. In the former approach, every single result is referred directly to the parametric value, while in the probabilistic method uncertainty related to analytical results is taken into account during the decision-making process. In the present research, laboratory uncertainty and uncertainty determined on the basis of results of analyses of duplicate samples collected in two Polish cities were compared and used in the probabilistic approach of water quality assessment. Using the probabilistic method, more results were considered to be “above the parametric value”. Most excesses were observed when the maximum allowable uncertainty as set out in the Regulation of the Minister of Health of 7 December 2017 was used, which is due to the highest values of these uncertainties. The lowest values above parametric values in the probabilistic approach were observed when measurement uncertainty was considered

Molecular dynamics simulations of energetic Ar cluster bombardment of Ag(111)

Large-scale molecular dynamics computer simulations are used to investigate the dynamics of material ejection during high-energy Ar_{n} cluster bombardment of Ag(111) at normal incidence. The silver sample containing 7 million atoms is bombarded with Ar_{n} projectiles (n=45-30000) with kinetic energy spanning from a few keV up to 1 MeV. Such a wide range of projectile parameters allows probing processes taking place during low-density collision cascade as well as during high-density events characteristic of micrometeorite bombardment in space. The material modifications and total sputtering yield of ejected particles are investigated. While at low-energy impacts, ejection of individual silver atoms is the main emission channel, the ejection of large clusters from the corona of the created crater dominates for the high-energy impacts

Department of Hydrogeology and Engineering Geology

The author describes a history and present activities of the Department of Hydrogeology and Engineering Geolog

Sputtering of benzene sample by large Ne, Ar and Kr clusters : molecular dynamics computer simulations

Molecular dynamics simulations are employed to probe the role of an impact angle on emission efficiency of organic molecules sputtered from benzene crystal bombarded by 15 keV $Ne_{2953}$, $Ar_{2953}$, and $Kr_{2953}$ clusters. It is found that both the cluster type and the angle of incidence have significant effect on the emission efficiency. The shape of the impact angle dependence does not resemble the dependence characteristic for medium size clusters ($C_{60}, Ar_{366}$), where sputtering yield only moderately increases with the impact angle, has a shallow maximum around 40° and then decreases. On the contrary, for the large projectiles ($Ne_{2953}, Ar_{2953}$, and $Kr_{2953}$) the emission efficiency steeply increases with the impact angle, has a pronounced maximum around 55° followed by rapid signal decay. It has been found that the sputtering yield is the most sensitive to the impact angle change for Kr cluster projectiles, while change of the impact angle of Ne projectile has the smallest effect on the efficiency of material ejection

Selected hydrochemical ratios of waters from inflows at level VI in "Wieliczka" Salt Mine

Relationships between major ions, such as Cl− , SO4 2− and Na+ and some microelements, may serve as good indicators of genesis and chemical transformations occurring during groundwater flow. The chemical composition of water from inflows at the level VI of “Wieliczka” Salt Mine is formed mainly by the dissolution of different types of salts caused by waters circulating in complicated systems of semipermeable rocks and fractured sandstones. This complicated geological structure is additionally disturbed by seven centuries of mining activity. Individual inflows are recharged by different flow systems, thus water/rock contact times are different. The authors analysed basic hydrochemical ratios: sodium/ chlorides (rNa+ /rCl− ), sulphides/chlorides (rSO4 2−·100/rCl− ) and chlorides/iodides (Cl− /I− ). The obtained results proved that hydrochemical ratios may serve as a supporting tool for better assessment of water threats in the western part of “Wieliczka” Salt Mine