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Although highly developed countries are trying to diversify away from coal-based energy, many economies rely on this resource. Its consumption results in the production of carbon dioxide, which promotes global warming, necessitating its sequestration. This paper presents the sorption–dilatometric relationships of hard coal samples differing in vitrinite and inertinite content. The studies were carried out under isothermal conditions (298 K) at a free pressure drop complemented by measurements under non-isothermal conditions (298 K to 323 K). The tests were performed on an original apparatus, based on the operation of an Arduino microcontroller. For the natural porosity to be preserved and for a better representation of the behaviour of the coal–gas system, samples in the form of cuboidal blocks were used, making this apparatus unique worldwide. Based on the study, it appears that the difference in petrographic composition affects the behaviour of the coal structure, influencing differences in the sorption–dilatometric properties. In the case of the sample with higher vitrinite content, the amount of adsorbed gases is higher. [ABSTRACT FROM AUTHOR]

The aim of this study was to investigate the ability of kinetic equations to describe the sorption kinetics and expansion rate of solid coal samples. In order to address his issue the sorption kinetics of methane and carbon dioxide on bituminous coals were studied. At the same time, the changes occurring in the sample’s overall dimensions, which accompanied sorption processes, were monitored. Experiments were carried out at high pressure by means of the volumetric method on a cubicoid solid samples. Several literature-based modeling approaches and equations are proposed to fit the kinetic curves of gas deposition, as well as the adequate kinetics of coal swelling. First equation represents the traditional approach to interpret experimental data in terms of fast and slow sorption process and consider the combination of two first-order rate functions. The other empirical kinetic equations are: the pseudo-second-order kinetic equation (PSOE), Elovich equation and the stretched exponential equation (SE). Two of the four equations are suitable to describe the kinetics of methane and carbon dioxide sorption and have been successfully used to quantify the observed dilatometric phenomena rates. The stretched exponential equation gave the best fit to the experimental data.

Expansion/contraction of coal, induced by the sorption of carbon dioxide and methane in isothermal and non-isothermal conditions, was measured. The investigation is of great importance in the context of validating the potential CO2 sequestration in unmined coal seams. Changes in temperature in underground coal beds can influence the sorption balance, resulting in strains in coal strata, which could lead to the desorption of gas and leaks to the ground surface. The research shows that the strains induced by CO2 sorption are about twice the size of those resulting from the sorption of CH4. The linear strains are anisotropic and greater in the direction perpendicular to the bedding plane. The results of the non-isothermal experiments show that a temperature increase gives rise to the sample swelling in the presence of methane, but a different pattern is observed for coal–CO2 systems, where sample contraction occurs. This behaviour is explained by the different mechanism of CH4 and CO2 deposition and by the diversity in the maceral composition of the samples. [ABSTRACT FROM AUTHOR]

Introduction: Cigarette smoking is one of the most common habits of the modern world. The World Health Organization (WHO) showed that about 30% of the world's population over the age of 15 smoked cigarettes. That gives the number of 1.1 billion smokers. It is known that the habit of smoking is a serious risk to human health and life. Cigarette smoke induces the formation of reactive oxygen species (ROS). ROS can cause direct damage of DNA chain and leads to the mutagenic and carcinogenic effect., The Aim of the Study: To evaluate the concentration of 8-hydroxy-2'-deoxyguanosine (8-OHdG) in the urine of smokers. Based on the obtained results an attempt to determine whether the concentration of 8-OH-dG in the urine can be an indicator of genotoxicity of tobacco smoke., Material and Methods: The study was conducted in 83 healthy volunteers, 63 smokers and 20 non-smokers (control group). The age of patients in both groups were in the range 20-60 years. Average age of women and men in the control group and the test group was 34 years. Duration of smoking was 1-30 years, the number of cigarettes smoked from 1 to over 20 per day. In the urine the concentration of 8-OH-dG was determined using Bioxytech® 8-OH-dG-EIA™Kit (manufactured by OXIS International, Inc., Portland, USA) and the concentration of creatinine using in vitro diagnostic kit BIOLABO. The concentration of 8-OHdG in urine was expressed in ng/g creatinine., Results: More than 3-fold increase in the concentration of 8-OHdG in the urine of smokers was found. The increase in the concentration of 8-OHdG in the urine depended on age, the amount of smoked cigarettes per 24 hours, duration of smoking and cigarette brands., Conclusions: The increase in the concentration of 8-OHdG in the urine of smokers, both women and men indicates DNA damage and the genotoxicity action of cigarette smoke. According to our previously conducted studies and examinations of other authors, it can be suggested that the concentration of 8-OHdG in urine may be considered as the sensitive and specific marker of oxidative DNA damage.