Space-Time Discretization of Maxwell's Equations in the Setting of Geometric Algebra

In this dissertation a FIT-like discretisation of Maxwell's equations is performed directly in four-dimensional space-time using the mathematical formalism of Clifford's Geometric Algebra. The thesis extends the Finite Integration Technique (FIT) to 4D space-time without introducing any non-relativistic assumptions. The coordinate-free formulation in terms of geometric algebra enhances explicitly relativistic, i.e., without splitting space and time, treatment, which reveals in the fact that any non-relativistic assumptions are not made. The relation of geometric algebra to the existing concepts from differential geometry in the language of differential forms is established in the context of electromagnetic field description. An alternative to the existing approaches formula for the discretisation of material laws on non-orthogonal mesh pairs is derived, investigated and applied. The developed theory is applied to obtain the condition for 3D problems when material matrices are diagonal, and due to quantitative nature of this condition a mesh optimisation procedure is proposed, as well as its limitations in 3D case, which do not occur in 2D, are derived. The other application is simulation of electromagnetic wave propagation in a rotating reference frame. Due to coordinate-free formalism and encoding the movement of the observer in 4D mesh's geometry, derivation of the numerical scheme for rotating observer's resembles the one for inertial (stationary) observers. In other words, relativistic coordinate-free treatment includes inertial and non-inertial observers as special cases, which do not need to be diversified. The comparison of the obtained numerical results with the ones known from literature is performed in order to validate the theoretical results

Benefits from Implementing the EPLOS System in Logistics Companies

Logistics companies are currently differently using IT tools to assist the planning of their operational activity. The functionalities of tools are also different. The paper presents the results of a research on the use of automated solutions to obtain the data necessary for logistics processes planning. It also presents a review of IT solutions used by TSL (transport, shipping, logistics) companies and the functionality of these tools. This allowed for the assessment of the potential of the EPLOS system to be used in TSL companies, as well as the benefits of implementing this system. In the paper, the selected results of a survey made in companies about the crucial data needed for efficient operating were presented. The summary indicates the main features that software should have in the era of the Industry 4.0 revolution

An Integrated EPLOS Database as a Tool Supporting TSL Companies

The paper presents the conceptual design of a database for the European Portal of Logistics Services (EPLOS) and its application. The database contains the data on logistics companies, the infrastructure for road, railway, inland, and air transport, as well as the data on the nodal elements of logistics infrastructure (warehouse facilities, seaports, transhipment terminals). Complete and verified information is the fundamental condition for rational decisions about the realization of logistics processes on a meso- and macroeconomic scale. Authors present the relations in the making of the EPLOS database, its assumed scope, and the potential benefits for the TSL market from accessing the EPLOS database

Climatic and anthropogenic drivers of zero-flow events in intermittent rivers in Poland

River intermittence was studied based on data from hydrological monitoring in Poland. We screened the entire state database and two another data sources applying the criterion for zero-flow event: discharge less than 0.0005 $m^{3}∙s^{–1}$, and found five intermittent rivers with catchment area from 9.2 to 303.7 $km^{2}$. We aimed at finding associations between intermittence and climatic driving forces (temperature and precipitation), and between intermittence and anthropogenic activity. We used the Spearman correlation coefficient, circular statistics, and statistical tests for trend. The concentration of zero-flow days, mostly in summer, and the decreasing trend in the standardised precipitation evapotranspiration index (SPEI) in all catchments at various aggregation levels, and an increasing trend in the total number of zero-flow days and in the maximum length of zero flow events in two rivers, were detected. The strong negative correlation (-0.62 ≤ ρ < 0) between intermittence and the SPEI backward lagged in time showed that intermittence resulted from prolonged deficits in climatic water balance due to increasing evapotranspiration. The reaction of the Noteć catchment, amplified by the anthropogenic pressure (brown coal mines), was reflected in the atypical shape of the rose diagram and in inhomogeneities in river discharges. The results show that the rose diagram can serve as an indicator of the degree of anthropogenic impact on runoff conditions

Linking soils and streams during events : response of stream water K+K^{+} concentration to soil exchangeable K+K^{+} concentration in small catchments with fragipan soils (Carpathian Foothills, Poland)

The study aimed to determine the linkage between soil exchangeable potassium ($K^{+}$) concentration and stream water $K^{+}$ concentration during rainfall and snowmelt events in small catchments with different land use (Carpathian Foothills, Poland). The complementary geochemical and hydrochemical approach used in the study produced new information on the role of particular soil horizons and contributing areas such as hillslope or riparian areas in $K^{+}$ delivery to stream channels during events. Horizons lying above the nearly impermeable fragipan (Btx) play the most important role in the process of $K^{+}$ influx to streams during most event types except snowmelts with frozen soils, in all the studied catchments. In the woodland catchment, rapid flushing of $K^{+}$ from the topsoil Ah horizon with higher hydraulic conductivity ($K_{sat}$) and higher exchangeable K+ concentrations than in the lying lower E horizon resulted in a clockwise hysteresis of $K^{+}$ in stream water during most events. In agricultural catchments, changes in stream water $K^{+}$ concentration during events were determined by distinct differences between soil exchangeable $K^{+}$ concentrations on hillslopes and in riparian areas

Regular black holes in an asymptotically de Sitter universe

A regular solution of the system of coupled equations of the nonlinear electrodynamics and gravity describing static and spherically-symmetric black holes in an asymptotically de Sitter universe is constructed and analyzed. Special emphasis is put on the degenerate configurations (when at least two horizons coincide) and their near horizon geometry. It is explicitly demonstrated that approximating the metric potentials in the region between the horizons by simple functions and making use of a limiting procedure one obtains the solutions constructed from maximally symmetric subspaces with different absolute values of radii. Topologically they are $AdS_{2}\times S^{2}$ for the cold black hole, $dS_{2}\times S^{2}$ when the event and cosmological horizon coincide, and the Pleba\'nski- Hacyan solution for the ultraextremal black hole. A physically interesting solution describing the lukewarm black holes is briefly analyze

Differential associations of inflammatory and endothelial biomarkers with disease activity in rheumatoid arthritis of short duration

Objectives. To estimate endothelial dysfunction in patients with rheumatoid arthritis (RA) of short duration in relation to disease activity based on the assessment of 28 joints (DAS28). Methods. We studied 29 patients (22 women, mean age 41 (SD, 9) years) with RA of short duration and 29 healthy controls. The RA subjects were divided into those with low (DAS28: 2.6–5.1, n=18) or high (DAS28>5.1, n=11) disease activity. Exclusion criteria included clinically overt atherosclerosis and other coexistent diseases. Biochemical markers of inflammatory activation and endothelial dysfunction were measured. Results. There were no significant intergroup differences in the majority of classical cardiovascular risk factors. High-sensitivity C-reactive protein, tumor necrosis factor-α, and interleukin-6 were increased in RA subjects. Compared to the controls, levels of soluble vascular cell adhesion molecule-1, von Willebrand factor, and pentraxin-3 were significantly elevated in RA subjects with low disease activity, exhibiting no further significant rises in those with high disease activity. Asymmetric dimethyl-L-arginine, soluble E-selectin, monocyte chemotactic protein-1, and osteoprotegerin were increased only in RA patients with high disease activity. Conclusions. Our findings might suggest a dissociation of pathways governing generalized and joint-specific inflammatory reactions from those involved in endothelial activation and inflammation within the vascular wall

Search for dark matter produced in association with bottom or top quarks in √s = 13 TeV pp collisions with the ATLAS detector

A search for weakly interacting massive particle dark matter produced in association with bottom or top quarks is presented. Final states containing third-generation quarks and miss- ing transverse momentum are considered. The analysis uses 36.1 fb−1 of proton–proton collision data recorded by the ATLAS experiment at √s = 13 TeV in 2015 and 2016. No significant excess of events above the estimated backgrounds is observed. The results are in- terpreted in the framework of simplified models of spin-0 dark-matter mediators. For colour- neutral spin-0 mediators produced in association with top quarks and decaying into a pair of dark-matter particles, mediator masses below 50 GeV are excluded assuming a dark-matter candidate mass of 1 GeV and unitary couplings. For scalar and pseudoscalar mediators produced in association with bottom quarks, the search sets limits on the production cross- section of 300 times the predicted rate for mediators with masses between 10 and 50 GeV and assuming a dark-matter mass of 1 GeV and unitary coupling. Constraints on colour- charged scalar simplified models are also presented. Assuming a dark-matter particle mass of 35 GeV, mediator particles with mass below 1.1 TeV are excluded for couplings yielding a dark-matter relic density consistent with measurements