Bezpieczeństwo: wymiar współczesny i perspektywy badań

Praca recenzowana / peer-reviewed paperPrezentowane wydawnictwo stanowi efekt obrad międzynarodowej konferencji naukowej zorganizowanej w dniach 12–13 października 2008 roku przez Katedrę Zarządzania Informacją, działającą w ramach Wydziału Ekonomii i Zarządzania, oraz, jak już wspomniano, przez Międzynarodowe Stowarzyszenie „Edukacja dla Obronności i Bezpieczeństwa”. Ambicją organizatorów konferencji było włączenie w tok dyskusji licznych przedstawicieli organów administracji państwa i samorządu, praktyki gospodarczej, nauki, mediów oraz studentów, zarówno z kraju, jak i z zagranicy

The application of natural zeolite to cement concrete intended for communications surfaces

The article presents the application of a cement substitute in the form of natural zeolite to cement concrete. The reference mix design intended for communications surfaces and a mix of modified composition taking into consideration zeolite content were prepared. The basic parameters of concrete mix components were specified, including basalt aggregate, cement and zeolite. The influence of the applied zeolite of a grain-size distribution up to 50μm on the obtained parameters of concrete mix and hardened concrete was determined. It was observed that the applied zeolite contributes to the modification of the internal structure of concrete composite and consequently to the increase of the mechanical and physical parameters of hardened concrete tested within diversified standard periods of time. Due to the fact that the resistance of concrete to cyclic freezing and thawing is the determinant of concrete durability, in the case of pavement structure, hardened concretes were subject to a frost resistance assessment. The influence of zeolite content on both internal and external frost resistance of hardened concrete was specified. SEM observations of the internal structure of concretes exposed to the influence of freezingthawing cycles proved the advantageous changes of zeolite occurrence in concrete mix. A reduction of cement quantity and its replacement thereof with the suggested zeolite allows obtaining a pavement quality concrete of a more favourable internal micro structure and distinguished by higher parameters

The Influence of the Aircraft Operating Fluids on the Mechanical Parameters of the Airport Surface Concrete

The authors of the article assessed the impact of operating fluids used to service aircraft on changing mechanical parameters of cement concrete intended for airport pavement. The research concerned concrete designed with the use of CEM I 42.5N LH NA low-alkali cement, broken granite aggregate, fine washed aggregate, and admixtures. The analysis included the assessment of changes in differences in endurance parameters over various research periods of up to 140 days. The obtained results allowed to carry out statistical analysis using the student’s T-test. Research has shown a significant impact of operational fluids used in aircraft on the surface concrete properties of the airport. A reduction in the compressive strength of concrete exposed to one of the tested operating liquid to a reduction of 7.2% was observed over a period of 140 days, while there was no significant impact of operating fluids on tensile strength at splitting

Usefulness of porphyry and amphibolites as a component of concrete for airfield pavements

Coarse aggregate used as part of cement concrete is of primary significance for the obtained parameters of hardened concrete. In case of concretes intended for airfield pavements, the application of granite grit is recommended. Alternative to this type of aggregate in the form of porphyry and amphibolites aggregate was suggested. In order to assess the suitability of different aggregate types for concrete mixes, their bulk density, absorbability, polishing resistance, abrasion and crushing resistance were determined. Also, the internal structure of the suggested aggregates and its influence on changes of hardened concrete composite structure were subject to the assessment. The influence of aggregate type on the structure of cement matrix and contact areas between the matrix and aggregate grains were specified. The observed changes, in case of the internal structure of concretes based on porphyry and amphibolites aggregates, with reference to granite aggregate, resulted in changes of mechanical and physical parameters. Analyses included the determination of bulk density, absorbability, compression, bending and splitting resistance. According to the obtained laboratory test results, the significant influence of the aggregate type applied to the mix on parameters of hardened concrete, with regard to the application thereof to the airfield pavements was proved

Influence of Operating Media on the Parameters of Cement Concrete Intended for Airfield Pavements

The article presents the influence of the suggested operating media on the modification of parameters of cement concrete intended for airfield pavements. Cement concrete contains cement CEM I 42,5, granite grit, fine washed aggregate, water and air entraining as well as plasticizing additive. Analyses included the assessment of changes in mechanical and physical parameters (weight absorbability and water capillary action) of hardened concrete. The observed changes were associated with the internal structure of concrete composite. Based on the obtained results, different influence of the applied operating media on mechanical parameters of hardened concrete was determined

Usefulness of porphyry and amphibolites as a component of concrete for airfield pavements

Coarse aggregate used as part of cement concrete is of primary significance for the obtained parameters of hardened concrete. In case of concretes intended for airfield pavements, the application of granite grit is recommended. Alternative to this type of aggregate in the form of porphyry and amphibolites aggregate was suggested. In order to assess the suitability of different aggregate types for concrete mixes, their bulk density, absorbability, polishing resistance, abrasion and crushing resistance were determined. Also, the internal structure of the suggested aggregates and its influence on changes of hardened concrete composite structure were subject to the assessment. The influence of aggregate type on the structure of cement matrix and contact areas between the matrix and aggregate grains were specified. The observed changes, in case of the internal structure of concretes based on porphyry and amphibolites aggregates, with reference to granite aggregate, resulted in changes of mechanical and physical parameters. Analyses included the determination of bulk density, absorbability, compression, bending and splitting resistance. According to the obtained laboratory test results, the significant influence of the aggregate type applied to the mix on parameters of hardened concrete, with regard to the application thereof to the airfield pavements was proved

The Influence of the Management (Motivational) Function on the Implementation of New Concepts of Management in Business Practices

The aim of the article is to discuss the results of a study about the influence of one of the management functions, the motivational function, on the implementation of new concepts in enterprises. The research includes such issues as the use of new concepts in accomplishing objectives as well as factors, which make companies work more effectively once these concepts have been introduced. This presentation and the detailed analysis of the empirical research conducted gives insight into how new concepts of management are used in practice

Antioxidant Activity of Bilirubin in Micellar and Liposomal Systems Is pH-Dependent

Bilirubin (BR), a product of heme catabolism, plays a critical role in biological systems. Although increased levels of BR result in hyperbilirubinemia or jaundice, there is increasing evidence that lower concentrations substantially decrease the risk of oxidative stress-mediated diseases due to antioxidant functions of BR. We studied the radical-trapping ability of BR in two model systems, micellar and liposomal, at a broad pH range. At pH kinh) within the range from 1.2 × 104 M−1 s−1 to 3.5 × 104 M−1 s−1, and in liposomal system, the activity of BR is comparable to α-tocopherol. This transition is likely facilitated by the ionization of carboxyl groups, leading to a conformational shift in BR and improved solubility/localization at the water/lipid interface. This is the first experimental evidence of the role of pH on the antioxidant activity of bilirubin, and the observed pH-dependent radical-trapping ability of BR holds practical significance, particularly in jaundice treatment where light therapy targets the skin’s weakly acidic surface. Minor adjustments toward neutral or alkaline pH can enhance radical-trapping action of BR, thereby mitigating oxidative stress induced with blue or violet light exposure